A N A T () M Y, 
DESCRIPTIVE AND SURGICAL. 
BY 
HENRY (JRAY, F.R.S., 
FELLOW OF THE ROYAL COLLEGE OB' SURGEONS; LECTURER ON ANATOMY AT ST. GEORGE'S 
HOSPITAL MEDICAL SCHOOL, LONDON. 
EDITED BY 
T. PICKERING PICK, F.R.C.S., 
consulting surgeon to st. george's hospital and to the victoria hospital for children, London; 
H. M. INSPECTOR OF ANATOMY IN ENGLAND AND WALES, 
AND 
ROBERT HOWDEN, M.A., M.B., C.M., 
PROFESSOR OF ANATOMY IN THE UNIVERSITY OF DURHAM; EXAMINER IN ANATOMY IN THE UNIVERSITIES 
OF DURHAM AND EDINBURGH, AND TO THE BOARD OF EDUCATION, SOUTH KENSINGTON. 
NEW AMERICAN EDITION. 
THOROUGHLY REVISED AND RE-EDITED WITH ADDITIONS 
BY 
JOHN CHALMERS DaCOSTA, M.D., 
PROFESSOR OF PRINCIPLES OF SURGERY AND PROFESSOR OF CLINICAL SURGERY IN JEFFERSON MEDICAL COLLEGE, 
PHILADELPHIA; SURGEON TO THE PHILADELPHIA HOSPITAL; CONSULTING SURGEON 
to st Joseph's hospital 
ILLUSTRATED WITH 1132 ELABORATE ENGRAVINGS. 
LEA BROTHERS & CO., 
PHILADELPHIA AND NEW YORK. 
1905. Entered according to Act of Congress, in the year 1905, by 
LEA BROTHERS & CO., 
in the office of the Librarian of Congress at Washington. All rights reserved. 
DORNAN, PRINTER. THIS 
NEW AMERICAN EDITION OF GRAY'S ANATOMY 
IS DEDICATED TO 
WILLIAM W. KEEN, M.D., LL.D., Hon. F.R.C.S. Eng. and Scot. 
THE DISTINGUISHED PROFESSOR OF SURGERY IN JEFFERSON 
MEDICAL COLLEGE 
AS AN EVIDENCE OF 
THE ADMIRATION, THE AFFECTION AND THE GRATITUDE OF HIS COLLEAGUE 
AND FORMER ASSISTANT 
THE EDITOR PREFACE. 
In this revision of Gray's Anatomy, the Editor has endeavored to reflect the 
development of the subject since the appearance of the last edition, and has 
sought to accomplish this without sacrificing those practical and didactic char- 
acteristics that have ever been the most notable features of the book. Radical 
innovations were undesirable, and original exposition was neither desirable nor 
possible. The Editor is responsible for some eliminations, many alterations, 
and a great number of additions; and it has been deemed unwise even to attempt 
to designate, by brackets or any other device, so great a number of changes and 
additions. 
In order that its pages might represent the world's best knowledge, American, 
English, French, and German text-books, monographs, and journal-articles have 
been freely consulted. In using statements from these numerous sources, the 
aim has been to give, in every instance, proper credit to the author. If, in some 
cases, this has not been done, the failure is the result of accident, and never of 
design. 
Among the many works thus utilized may be mentioned the three composite 
treatises edited by Gerrish, Cunningham, and Morris, respectively; Poirier and 
Charpy, Testut, Spalteholz (which has recently been translated into English 
and edited by Professor Barker); Hughes's Practical Anatomy, edited and com- 
pleted by Keith; McClellan's Regional Anatomy; Deaver's Surgical Anatomy ; 
Treves's Applied Anatomy; Owens's Manual of Anatomy; Eisendrath's Clinical 
Anatomy; Byron Robinson, on the Peritoneum; and the text-books of Quain 
and MacAllister. Special credit is due to the chapter on the "Lymphatics" in 
Poirier and Charpy (translated and edited by Leaf); to the admirable section 
on the "Nervous System," written by Professor Cunningham in his text-book; 
and to Professor Santee's extremely valuable monograph on the Anatomy of the 
Brain and Spinal Cord. 
The Latin, new or international nomenclature has been introduced in 
parentheses, following the names still currently used in English-speaking coun- 
tries. This system of coupling the current and the new names answers the needs 
of all students, and will facilitate the much-to-be-desired adoption of the new 
nomenclature. The Latin nomenclature was recommended by an international 
committee, was published by Wilhelm His, and has been generally accepted by 
anatomists. Owing to its accuracy and its simplicity, it seems destined eventu- 
ally to succeed the older methods of designation; but in this country at least, 
the older nomenclature is still too firmly fixed to be entirely and suddenly 
abandoned. 
Gray's Anatomy has been noted for the extent and the elaborate nature of its 
illustrations. This new edition exceeds its predecessor in the number of engrav- 
ings and in the use of colors. The series now aggregates over eleven hundred, of 
which about five hundred are new in this edition. Particular acknowledgment for 
originals is due to Spalteholz, Cunningham, Poirier and Charpy, Testut, Gerrish, 
Byron Robinson, and the Atlas of Human Anatomy by Carl Toldt, assisted by 
V VI 
PREFACE 
A. D. Rosa (recently translated into English and edited by M. Eden Paul). The 
pictures taken from these various sources have been re-engraved, and in some 
instances have been modified. 
In this edition the special articles on "Histology" and "Embryology," hitherto 
placed at the end of the book, have been eliminated. The extent, the importance, 
and the technical nature of these great subjects have led to the creation of special 
chairs for their teaching; and it seems desirable that the text-books used by 
the students should be those written by men devoted to these specialties. No 
single volume, in these days, can offer adequate instruction on anatomy, histology, 
and embryology; and to attempt it would be unwise. The bearings of histology 
and embryology upon anatomy are close and highly important. The Editor has 
.set forth the essential points of these subjects when the elucidation of the text 
(demanded it by means of resumes. For these, he has drawn chiefly upon the 
♦excellent sections in the previous edition of Gray (which were edited by Robert 
Howden), supplementing them from the Histology and Microscopic Anatomy 
"by Szymonowicz (translated by John Bruce MacCallum), the text-book of 
Histology by Bohm and von Davidoff (edited by G. Carl Huber), and the text- 
book of Embryology by John Clement Heisler. The clear and instructive surgical 
notes of Mr. Pick have, of course, been retained; although, here and there, they 
have been modified or added to, in accordance with the views of the day. 
Because of an oversight the foot-notes, thirty-five in number, from page 49 to 
page 497 inclusive, are not credited to the Editors of the 15th English edition. 
Subsequent to page 497 proper credit is given for foot-notes from the English 
editors. 
The Editor desires cordially to express his sense of indebtedness and gratitude 
to Dr. Howard Dehoney, Senior Assistant Demonstrator of Anatomy in the 
Jefferson Medical College, for his able and conscientious aid and collaboration. 
When a book has been edited many times by many men, the views and the 
style of the author are sure to be more or less obscured. The Editor of this 
edition hopes that Gray's Anatomy has not suffered too many things at his 
hands. 
John Chalmers Da Costa. 
Philadelphia, 1905. PUBLISHERS' NOTE. 
Henry Gray died young, but left in his masterpiece imperishable evidence 
of his two-fold genius, on the one hand a profound capacity to grasp the structure 
of the human body, and on the other an equal insight into the mind and the best 
method of imparting knowledge. His work immediately attained its merited 
pre-eminence, a position which the many excellent treatises of the past fifty years 
have only rendered more conspicuous. 
During this period frequent revisions have kept Gray always abreast of the 
active development of its subject. Among its editors it has numbered many of 
the ablest anatomists on both sides of the Atlantic. The services of Dr. DaCosta 
were sought by the Publishers by reason of his combined qualifications as an 
anatomist, a teacher and a surgeon. He has borne in mind the Author's original 
purpose, namely, to facilitate to the utmost the work of instructors and students, 
and to afford the physician and surgeon the assistance necessary in practice. 
He has revised every page, elaborating the text where necessary to cover the 
latest developments, and to ensure due proportion, and has greatly enriched the 
illustrations both in number and in the use of colors. The names of the parts 
are engraved directly upon them, a feature original with Gray and peculiar to 
his work. The advantage is obvious. Ample directions are given for dissection. 
The new nomenclature has been introduced in parentheses following the names 
still in common use, an arrangement preferable to either system alone. The 
book is thoroughly organized in its headings and with heavy type catchwords 
in the text, so that the student readily gains a knowledge of the parts in their 
anatomical dependence. 
From the foregoing outline it is not difficult to appreciate the reasons for the 
fact often observed that Gray is the easiest work from which to teach, to learn, 
to prepare for examinations for collegiate degrees and state licenses, and to use 
for reference in the practice of medicine and surgery. 
VII CONTENTS. 
DESCRIPTIVE AND SURGICAL ANATOMY, 
OSTEOLOGY-THE SKELETON. 
PAGE 
The Skeleton 33 
Number of the Bones 33 
Form of Bones 33 
Long Bones 33 
Short Bones 33 
Flat Bones 34 
Irregular Bones 34 
Surfaces of Bones 34 
Structure of Bone 34 
Bloodvessels of Bone ....... 39 
Chemical Composition of Bone .... 41 
Ossification and Growth of Bone ... 42 
I 
The Vertebral or Spinal Column. 
General Characters of a Vertebra. 
The Cervical Vertebrae ...... 49 
Atlas 50 
Axis 52 
Seventh Cervical 53 
The Thoracic or Dorsal Vertebrae ... 53 
Peculiar Dorsal Vertebrae .... 55 
The Lumbar Vertebrae 56 
•Structure of the Vertebrae 58 
Development of the Vertebrae .... 58 
Development of the Atlas 59 
Development of the Axis 59 
Development of the Seventh Cervical . . 60 
Development of the Lumbar Vertebrae . 60 
Progress of Ossification in the Spine Gener- 
ally 60 
The Sacral and Coccygeal Vertebrae . 61 
Sacrum 61 
Differences in the Sacrum of the 
Male and Female .... 64 
Peculiarities of the Sacrum . . 64 
Coccyx 65 
The Vertebral Column or Spine in General . 67 
Surface Form of the Vertebral Column . . 69 
Surgical Anatomy of the Vertebral Column 69 
The Skull. 
The Cerebral Cranium. 
The Occipital Bone 71 
The Parietal Bone 76 
The Frontal Bone 79 
Vertical Portion of the Frontal Bone . 79 
Horizontal or Orbital Portion of the 
Frontal Bone 81 
The Temporal Bone 83 
Squamous Portion of the Temporal 
Bone 831 
The Mastoid Portion of the Temporal 
Bone 851 
The Petrous Portion of the Temporal 
Bone 88 I 
PAGE 
The Sphenoid Bone 92 
The Body of the Sphenoid Bone . . 92 
The Greater or Temporal Wings of the 
Sphenoid Bone 95 
The Lesser or Orbital Wings of the 
Sphenoid Bone 96 
The Pterygoid Processes of the Sphe- 
noid Bone 96 
The Sphenoidal Spongy Bone ... 97 
The Ethmoid Bone 98 
The Horizontal Lamina or Cribriform 
Plate of the Ethmoid Bone ... 99 
The Vertical or Perpendicular Lamina 
or Plate of the Ethmoid Bone . . 100 
The Lateral Mass or Labyrinth of the 
Ethmoid Bone . . . . . 100 
Development of the Cranium . 102 
The Fontanelles . . . . . . 102 
Supernumerary or Wormian Bones . 103 
Congenital Fissures and Gaps . . . 104 
Bones of the Face. 
The Nasal Bones 104 
The Superior Maxillary Bones . . . 105 
The Body of the Superior Maxilla . . 105 
The Processes of the Superior Maxillae 109 
Malar Process of the Superior Max- 
illa 109 
Nasal Process of the Superior Max- 
illa 109 
Alveolar Process of the Superior 
Maxilla 109 
Palate Process of the Superior 
Maxilla 110 
Changes Produced in the Upper Jaw by Age 112 
The Lachrymal Bone 112 
The Malar Bone 113 
The Palate Bone 115 
The Horizontal Plate of the Palate 
Bone 116 
The Vertical or Perpendicular Plate of 
the Palate Bone 117 
The Inferior Turbinated Bone . . . 119 
The Vomer 120 
The Maxillary Bone, Inferior Maxilla, Man- 
dible or Lower Jaw 122 
The Horizontal Portion or Body of the 
Mandible 122 
The Perpendicular Portion or Rami of 
the Mandible 124 
Changes Produced in the Lower Jaw by 
Age .125 
The Sutures 127 
The Skull as a Whole. 
The Vertex of the Skull 129 
The Base of the Skull 130 
IX CONTENTS 
X 
PAGE 
The Lateral Region of the Skull . 136 
The Temporal Fossa 137 
The Mastoid Portion 138 
The Zygomatic or Infratemporal Fossa 138 
The Spheno-maxillary or Pterygo-pala- 
tine Fossa 139 
The Anterior Region of the Skull . . 139 
Orbits, Orbital Cavities or Orbital Fossae 140 
The Nasal Cavity 142 
Difference in Size and Form of the Cranium 146 
Surface Form of the Skull 147 
Fixed Points for Measurement of the Skull 149 
Surgical Anatomy of the Skull . . . . 149 
The Hyoid or Lingual Bone 153 
The Thorax. 
The Sternum 155 
The Ribs 159 
Common Characters of the Ribs . . 161 
Peculiar Ribs 162 
The Costal Cartilages 164 
Surface Form of the Chest 165 
Surgical Anatomy of the Chest . . . . 165 
The Upper Extremity. 
The Shoulder Girdle. 
The Clavicle .167 
Surface Form of the Clavicle . . . 170 
Surgical Anatomy of the Clavicle . . 170 
The Scapula 171 
Surface Form of the Scapula . . . 176 
Surgical Anatomy of the Scapula . . 177 
The Arm. 
The Humerus . 177 
Surface Form of the Humerus . . . 183 
Surgical Anatomy of the Humerus . 183 
The Forearm. 
The Ulna 184 
Surface Form of the Ulna .... 189 
The Radius 190 
Surface Form of the Radius . 192 
Surgical Anatomy of the Radius and 
Ulna 192 
The Hand. 
The Carpus 193 
Common Characters of the Carpal Bones 193 
Bones of the Upper Row .... 195 
Scaphoid or Navicular Bone . . 195 
Semilunar Bone 196 
Cuneiform Bone 197 
Pisiform Bone 197 
Bones of the Lower Row .... 198 
Trapezium 198 
Trapezoid 198 
Os Magnum 199 
Unciform 199 
PAGE 
The Metacarpus 200 
Common Characters of the Metacarpal 
Bones 200 
Peculiar Characters of the Metacarpal 
Bones 201 
The Phalanges of the Hand 204 
Surface Form of the Bones of the Hand . 204 
Surgical Anatomy of the Bones of the Hand 205 
Development of the Bones of the Hand . 205 
The Lower Extremity. 
The Pelvic Girdle. 
The Os Innominatum 207 
The Ilium 207 
The Ischium 210 
The Pubis 212 
The Cotyloid Cavity or Acetabulum . 213 
The Obturator or Thyroid Foramen . 214 
The Pelvis 215 
The False Pelvis 215 
The True Pelvis . . . < 216 
Position of the Pelvis 218 
Axes of the Pelvis 218 
Differences between the Male and the 
Female Pelvis 219 
Surface Form of the Pelvis .... 220 
Surgical Anatomy of the Pelvis . . 220 
The Thigh. 
The Femur or Thigh Bone 221 
Surface Form of the Femur . . . 229 
Surgical Anatomy of the Femur . . 229 
The Leg. 
The Patella or Knee-cap 230 
Surface Form of the Patella . . .231 
Surgical Anatomy of the Patella . . 231 
The Tibia or Shin Bone 233 
Surface Form of the Tibia .... 236 
The Fibula or Calf Bone 237 
Surface Form of the Fibula . 239 
Surgical Anatomy of Bones of the Leg 239 
The Foot. 
The Tarsus 242 
The Calcaneus or Heel Bone . . . 242 
The Astragalus or Ankle Bone . . . 244 
The Cuboid 245 
Scaphoid or Navicular Bone . . 246 
Cuneiform or Wedge Bones .... 247 
The Metatarsal Bones 249 
Common Characters of Metatarsal Bones 249 
Peculiar Characters of Metatarsal Bones 249 
The Phalanges of the Foot 252 
Development of the Foot 253 
Construction of the Foot as a Whole . 254 
Surface Form of the Foot 255 
Surgical Anatomy of the Foot .... 256 
Sesamoid Bones 257 
THE ARTICULATIONS OR JOINTS. 
Structures Composing the Joints . . . 259 
Bone 259 
Cartilage 259 
Ligaments 261 
Synovial Membranes 262 
Forms of Articulation: 
Synarthrosis 264 
Amphiarthrosis 264 
Diarthrosis 265 
The Kinds of Movement Admitted in 
Joints 266 
Ligamentous Action of Muscles .... 268 
Articulations of the Trunk. 
Articulations of the Vertebral Column . 269 
Articulations of the Atlas with the Axis 274 
Articulations of the Spine with the Cranium. 
Articulation of the Atlas with the Occipital 
Bone 276 
Articulation of the Axis with the Occipital 
Bone 278 
Surgical Anatomy of Articulations of the 
Spine . . 279 CONTENTS 
XI 
PAGE 
Articulation of the Lower Jaw or the Tem- 
poro-mandibular Articulation . . 280 
Surface Form 282 
Surgical Anatomy 282 
Articulations of the Ribs with the Vertebrae 
or the Costo-vertebral Articulations . . 283 
Articulation of the Cartilages of the Ribs 
with the Sternum, etc., or the Costo- 
sternal Articulations 287 
Articulations of the Cartilages of the 
Ribs with Each Other or the Inter- 
chondral Articulations .... 289 
Articulations of the Ribs with their Car- 
tilages or the Costo-chondral Artic- 
ulations 290 
Articulations of the Sternum .... 290 
Articulations of the Vertebral Column with 
the Pelvis 290 
Articulations of the Pelvis 292 
Articulation of the Sacrum and Ilium . 292 
Ligaments passing between the Sacrum 
and Ischium 292 
Articulation of the Sacrum and Coccyx 294 
Articulation of the Ossa Pubis . . . 296 
Articulations of the Upper Extremity. 
Sterno-clavicular Articulation .... 297 
Surface Form 299 
Surgical Anatomy 299 
Acromio-clavicular Articulation or Scapulo- 
clavicular Articulation .... 299 
Surface Form 301 
Surgical Anatomy 301 
Proper Ligaments of the Scapula . . 301 
The Shoulder-joint 303 
Surface Form of the Shoulder-joint . 307 
Surgical Anatomy of the Shoulder- 
joint 307 
The Elbow-joint 308 
Surface Form of the Elbow-joint . . 312 
Surgical Anatomy of the Elbow-joint . 312 
Radio-ulnar Articulation 313 
Superior or Proximal Radio-ulnar Artic- 
ulation 314 
Surface Form 314 
Surgical Anatomy 314 
Middle Radio-ulnar Ligaments . . 314 
Inferior or Distal Radio-ulnar Artic- 
ulation 315 
Surface Form 317 
Radio-carpal or Wrist-joint 317 
Surface Form of Wrist-joint . . . 318 
Surgical Anatomy of Wrist-joint . . 318 
Articulations of the Carpus 319 
Articulations of the First Row of Carpal 
Bones 319 
Articulations of the Second Row of Car- 
pal Bones 319 
Articulations of the Two Rows of Car- 
pal Bones 320 
PAGE. 
Carpo-metacarpal Articulations . . . .321 
Articulation of the Metacarpal Bone of 
the Thumb with the Trapezium 321 
Articulations of the Metacarpal Bones of 
the Four Inner Fingers with the Carpus 322 
Articulations of the Metacarpal Bones 
with Each Other 324 
Metacarpo-phalangeal Articulations . . 324 
Surface Form of Metacarpo-phalangeal 
Articulations 324 
Articulations of the Phalanges .... 325 
Articulations of the Lower Extremity. 
The Hip-joint 325 
Surface Form of the Hip-joint . . . 333 
Surgical Anatomy of the Hip-joint . 333 
The Knee-joint 334 
Surface Form of the Knee-joint . 343 
Surgical Anatomy of the Knee-joint . 343 
Tibio-fibular Articulation 345 
Superior Tibio-fibular Articulation . 345 
Middle Tibio-fibular Ligament or Inter- 
osseous Membrane 346 
Inferior Tibio-fibular Articulation . . 346 
The Tibio-tarsal Articulation or Ankle-joint 347 
Surface Form of Ankle-joint . . . 351 
Surgical Anatomy of Ankle-joint . . 351 
Articulations of the Tarsus 352 
Articulation of the Os Calcis and As- 
tragalus or the Calcaneo-astragaloid 
Articulation 352 
Articulation of the Os Calcis with the 
Cuboid or the Calcaneo-cuboid Artic- 
ulation 353 
The Ligaments connecting the Os Calcis 
and Scaphoid or the Calcaneo- 
scaphoid Articulation Ligaments 353 
Surgical Anatomy 354 
Articulation of the Astragalus with the 
Scaphoid Bone or the Astragalo- 
scaphoid Articulation .... 354 
The Articulation of the Scaphoid with 
the Cuneiform Bones 355 
The Articulation of the Scaphoid with 
the Cuboid 355 
The Articulations of the Cuneiform 
Bones with Each Other or the Inter- 
cuneiform Articulations .... 355 
The Articulation of the External Cunei- 
form Bone with the Cuboid . 356 
Surgical Anatomy 356 
Tarso-metatarsal Articulations .... 357 
Articulations of the Metatarsal Bones with 
Each Other 358 
The Synovial Membranes in the Tarsal 
and Metatarsal Joints 358 
Metatarso-phalangeal Articulations . . 359 
Articulations of the Phalanges .... 359 
Surface Form 360 
Surgical Anatomy 360 
THE MUSCLES AND FASCIAE. 
General Description of Muscles . . . .361 
General Description of Tendons . . . 363 
General Description of Aponeuroses . . 363 
General Description of Fasciae .... 364 
Muscles and Fasciae of the Cranium and 
Face. 
Subdivision into Groups 365 
The Cranial Region 366 
Dissection 366 
Superficial Fascia 366 
Surgical Anatomy 367 
The Occipito-frontalis 367 
Surgical Anatomy 368 
The Auricular Region 369 
Dissection 369 
Attrahens Auriculam or Aurem . . 369 
Attollens Auriculam or Aurem. . . 369 
Retrahens Auriculam or Aurem . . 369 
The Palpebral Region 370 
Dissection 370 
Orbicularis Palpebrarum .... 370 
Corrugator Supercilii 371 
Levator Palpebrse 371 
Tensor Tarsi or Horner's Muscle . 371 
The Orbital Region 372 
Levator Palpebrse Superioris . 372 
Superior Rectus 373 
Inferior Rectus 373 XII 
CONTENTS 
PAGE 
The Orbital Region- 
External Rectus 373 
Superior Oblique 373 
Inferior Oblique 374 
Fasciae of the Orbit 374 
Surgical Anatomy 575 
The Nasal Region 575 
Pyramidalis Nasi 375 
Levator Labii Superioris Alaeque Nasi 375 
Dilator Naris Posterior 376 
Dilator Naris Anterior 376 
Compressor Nasi 376 
Compressor Narium Minor . . . . 376 
Depressor Alae Nasi 376 
The Superior Maxillary Region .... 376 
Levator Labii Superioris .... 376 
Levator Anguli Oris 377 
Zygomaticus Major 377 
Zygomaticus Minor 377 
The Mandibular Region 377 
Dissection 377 
Levator Labii Inferioris or Levator 
Menti 378 
Depressor Labii Inferioris or Quadratus 
Menti 378 
Depressor Anguli Oris or Triangularis 
Menti 378 
The Intermaxillary Region 378 
Dissection 378 
Orbicularis Oris 378 
Buccinator 380 
Risorius or Santorini's Muscle . . . 380 
The Temporo-mandibular Region . . . 381 
Masseteric Fascia 381 
Masseter Muscle 381 
Temporal Fascia 381 
Dissection 382 
Temporal Muscle 382 
The Pterygo-mandibular Region . . 383 
Dissection 383 
External Pterygoid Muscle .... 383 
Internal Pterygoid Muscle .... 383 
Surface Form of Muscles of Head and Face 385 
Muscles and Fascia of the Neck. 
Subdivision in Groups 385 
The Superficial Cervical Region .... 386 
Dissection 386 
Superficial Cervical Fascia .... 386 
Platysma Myoides 386 
Deep Cervical Fascia 387 
Surgical Anatomy 389 
Sterno-mastoid or Sterno-cleido-mastoid 389 
Surface Form 391 
Surgical Anatomy . . . . .391 
The Infra-hyoid Region . . . . . .391 
Dissection 391 
Sterno-hyoid 391 
Sterno-thyroid 392 
Thyro-hyoid 392 
Omo-hyoid 393 
The Supra-hyoid Region 393 
Dissection 393 
Digastric 393 
Stylo-hyoid 394 
Mylo-hyoid 394 
Dissection 395 
Genio-hyoid 395 
The Lingual Region 396 
Dissection 396 ] 
Genio-hyo-glossus 396 I 
Hyo-glossus 397 ' 
Chondro-glossus 397 
Stylo-glossus 397 
Palato-glossus or Constrictor Isthmi 
Faucium 398 I 
Muscular Substance of the Tongue . 398 
Surgical Anatomy 400 | 
PAGE 
The Pharyngeal Region 7 400 
Dissection 400 
Inferior Constrictor 400 
Middle Constrictor 401 
Superior Constrictor 401 
Stylo-pharyngeus 403 
The Palatal Region 403 
Dissection 403 
Levator Palati 403 
Circumflexus or Tensor Palati . . 404 
Palatine Aponeurosis 404 
Azygos Uvulae 405 
Palato-glossus or Constrictor Isthmi 
F aucium 405 
Palato-pharyngeus 405 
Salpingo-pharyngeus 405 
Surgical Anatomy 406 
The Anterior Vertebral Region .... 406 
Rectus Capitis Anticus Major or Longus 
Capitis 406 
Rectus Capitis Anticus Minor . . 407 
Rectus Capitis Lateralis .... 407 
Longus Colli 407 
The Lateral Vertebral Region .... 408 
Scalenus Anticus 408 
Scalenus Posticus 409 
Surface Form of Muscles of the Neck . . 409 
Muscles and Fascia of the Trunk. 
Subdivision into Groups 410 
Muscles of the Back. 
Subdivision into Groups 410 
The First Layer 410 
Dissection 410 
Superficial Fascia 411 
Deep Fascia 411 
Trapezius 411 
Ligamentum Nuchae 413 
Latissimus Dorsi 413 
The Second Layer 414 
Dissection 414 
Levator Anguli Scapulae .... 414 
Rhomboideus Minor 414 
Rhomboideus Major 414 
The Third Layer 415 
Dissection 415 
Serratus Posticus Superior . 415 
Serratus Posticus Inferior .... 415 
Vertebral Aponeurosis 416 
Lumbar Fascia or Aponeurosis 416 
Splenius 416 
Splenius Capitis 416 
Splenius Colli 416 
The Fourth Layer 417 
Dissection 417 
Erector Spinae 417 
Uio-costalis or Sacro-lumbalis . . 419 
Musculus Accessorius ad llio-cos- 
talem 419 
Cervicalis Ascendens .... 419 
Longissimus Dorsi 419 
Transversalis Cervicis or Trans- 
versalis Colli 419 
Trachelo-mastoid 419 
Spinalis Dorsi 419 
Spinalis Colli 420 
Complexus 420 
The Fifth Layer 420 
Dissection 420 
Semispinalis Dorsi 421 
Semispinalis Colli 421 
Multifidus Spinae 421 
Rota tores Spinae 421 
Supraspinales 421 
Interspinales 421 
Extensor Coccygis 422 
Intertransversales 422 
Rectus Capitis Posticus Major . 422 CONTENTS 
XIII 
PAGE 
The Fifth Layer- 
Rectus Capitis Posticus Minor . . . 422 
Obliquus Capitis Inferior . . . . 422 
Obliquus Capitis Superior .... 422 
Surface Form of Muscles of the Back . . 424 
Muscles and Fasciae of the Thorax. 
Intercostal Fascia 424 
Intercostal Muscles 425 
External Intercostals 425 
Internal Intercostals 425 
Infracostales 425 
Triangularis Stemi 425 
Levatores Costarum 426 
Diaphragm 427 
Ligamentum Arcuatum Internum . . 427 
Ligamentum Arcuatum Externum . 427 
Central Tendon of the Diaphragm . . 429 
The Openings of the Diaphragm . . 429 
Muscles of Inspiration and Expiration 432 
Muscles of the Abdomen. 
The Superficial Muscles of the Abdomen . 432 
Dissection 432 
Superficial Fascia 433 
Deep Fascia ........ 433 
External or Descending Oblique . . 433 
Aponeurosis of External Oblique . 434 
External Abdominal Ring . . 436 
External Pillar or Inferior Crus . 436 
Internal Pillar or Superior Crus . 436 
Intercolumnar Fibres .... 436 
Poupart's Ligament .... 436 
Gimbernat's Ligament . . . 437 
Triangular Fascia or Colles's Liga- 
ment 437 
Ligament of Cooper .... 437 
Suspensory Ligament of the Penis 437 
Suspensory Ligament of the Clitoris 437 
Internal or Ascending Oblique . . . 437 
Aponeurosis of Internal Oblique . 439 
Cremaster Muscle 439 
Transversalis 442 
Dissection 442 
Rectus Abdominis 442 
Pyramidalis 444 
The Linea Alba 444 
The Line® Semilunares . . . 445 
The Lineae Transversae .... 445 
The Transversalis Fascia .... 445 
Internal or Deep Abdominal Ring 446 
The Inguinal or Spermatic Canal . . 448 
The Deep Crural Arch 448 
Cooper's Ligament 448 
Surface Forms of Muscles of the Abdomen 448 
The Deep Muscles of the Abdomen . . 449 
The Fascia Covering the Quadratus 
Lumborum 449 
Quadratus Lumborum 449 
Muscles of the Pelvic Outlet. 
The Muscles of the Ischio-rectal Region 7 449 
The Corrugator Cutis Ani .... 449 
External Sphincter Ani 450 
Internal Sphincter Ani 451 
Levator Ani 451 
Pubococcygeus Muscle .... 452 
Iliococcygeus Muscle .... 454 
Coccygeus 455 
The Muscles and Fasciae of the Perinaeum in 
the Male 455 
Superficial Fascia 455 
The Central Tendinous Point of the 
Perinaeum 456 
Transversus Perinei Superficialis . 457 
Accelerator Urinae 457 
Erector Penis 458 
Triangular Ligament .... 458 
Compressor or Constrictor Urethrae . 460 
PAGE 
The Muscles of the Perinaeum in the Female 460 
Transversus Perinei Superficialis . . 460 
Sphincter Vaginae 461 
Erector Clitoridis 461 
Triangular Ligament .... 462 
Compressor Urethrae 462 
Muscles and Fasci.e of the Upper 
Extremity. 
Subdivision into Groups 462 
Dissection of Pectoral Region and Axilla . 463 
The Muscles and Fascia: of the Thoracic 
Region. 
The Anterior Thoracic Region .... 463 
Superficial Fascia 463 
Deep Fascia 463 
Pectoralis Major 464 
Dissection 467 
Costo-coracoid Membrane or Clavipec- 
toral Fascia 467 
Pectoralis Minor 468 
Subclavius 468 
The Lateral Thoracic Region .... 468 
Serratus Magnus 468 
Surgical Anatomy 469 
Dissection 470 
Muscles and Fascia of Shoulder and Arm. 
Superficial Fascia 470 
Deep Fascia 470 
The Acromial Region 470 
Deep Fascia 470 
Deltoid 470 
Surgical Anatomy 471 
The Anterior Scapular Region . . . .471 
Dissection 471 
The Subscapular Fascia 471 
Subscapularis 471 
The Posterior Scapular Region .... 472 
Dissection 472 
Supraspinatus Fascia 472 
Supraspinatus Muscle 472 
Infraspinatus Fascia 472 
Infraspinatus Muscle 472 
Teres Minor 473 
Teres Major 474 
The Muscles and Fasciae of the Arm. 
The Anterior Humeral Region .... 474 
Dissection 474 
Deep Fascia 474 
Coraco-brachialis 475 
Biceps or Biceps Flexor Cubiti . .475 
Brachialis Anticus 476 
The Posterior Humeral Region .... 477 
Triceps or Triceps Extensor Cubiti . 477 
Subanconeus 478 
Surgical Anatomy 478 
Muscles and Fascia of the Forearm. 
Dissection 478 
Deep Fascia ' . . 478 
The Anterior Radio-ulnar Region . . 479 
The Superficial Layer 479 
Pronator Radii Teres .... 479 
Surgical Anatomy .... 479 
Flexor Carpi Radialis . . . .479 
Palmaris Longus 480 
Flexor Carpi Ulnaris .... 480 
Flexor Sublimis Digitorum . 481 
The Deep Layer 482 
Dissection 482 
Flexor Profundus Digitorum . 482 
Flexor Longus Pollicis .... 482 
Pronator Quadratus .... 483 
Surgical Anatomy 484 XIV 
CONTENTS 
PAGE 
The Radial Region . 484 
Dissection 484 
Supinator Longus 484 
Extensor Carpi Radialis Longior . . 485 
Extensor Carpi Radialis Brevier . . 485 
The Posterior Radio-ulnar Region . . . 486 
The Superficial Layer 486 
Extensor Communis Digitorum . 486 
Extensor Minimi Digiti . . . 487 
Extensor Carpi Ulnaris . . 487 
Anconeus 487 
The Deep Layer 487 
Supinator Radii Brevis . . . 487 
Extensor Ossis Metacarpi Pollicis 489 
Extensor Brevis Pollicis . . . 489 
Extensor Longus Pollicis . . . 489 
Extensor Indicis 490 
Surgical Anatomy 490 
Muscles and Fasciae of the Hand. 
Dissection 491 
Ligamentum Carpi Volare 491 
Anterior Annular Ligament 491 
The Synovial Membranes of the Flexor Ten- 
dons at the Wrist 492 
Surgical Anatomy 492 
Bursae about the Hand and Wrist . . . 492 
Posterior Annular Ligament 493 
The Deep Palmar Fascia 493 
The Superficial Transverse Ligament of 
the Fingers 494 
Surgical Anatomy 494 
The Radial Region 495 
Abductor Pollicis 495 
Opponens Pollicis 496 
Flexor Brevis Pollicis 497 
Adductor Obliquus Pollicis .... 497 
Adductor Transversus Pollicis . 497 
The Ulnar Region 498 
Palmaris Brevis 498 
Abductor Minimi Digiti 498 
Flexor Brevis Minimi Digiti . . 498 
Opponens Minimi Digiti .... 498 
The Middle Palmar Region 499 
Lumbricales 499 
Interossei 499 
Surface Form of Muscles of the Upper Ex- 
tremity 500 
Surgical Anatomy of Muscles of the Upper 
Extremity 503 
Muscles and Fasciae of the Lower 
Extremity. 
Subdivision into Groups 507 
Muscles and Fasciae of the Iliac Region. 
Dissection 508 
Iliac Fascia 508 
Psoas Magnus 509 
Psoas Parvus 510 
Iliacus 510 
Surgical Anatomy 511 
Muscles and Fasciae of the Thigh. 
The Anterior Femoral Region , 512 
Dissection 512 
Superficial Fascia 512 
Deep Fascia or Fascia Lata 513 
Surgical Anatomy 515 
Tensor Fasciae Femoris 515 
Sartorius 516 
Quadriceps Extensor 516 
Rectus Femoris 516 
Vastus Externus 517 
Vastus Internus 517 
Crureus 517 
Subcrureus 518 
Surgical Anatomy 518 
PAGE: 
The Internal Femoral Region .... 519 
Dissection 519 
Gracilis 519 
Pectineus 519 
Adductor Longus 519 
Adductor Brevis 520 
Adductor Magnus 520 
Hunter's Canal 521 
Surgical Anatomy 522. 
The Muscles and Fasciae of the Hip. 
The Gluteal Region 522' 
Dissection 522 
Gluteus Maximus 523 
Gluteus Medius 523 
Gluteus Minimus 523 
Pyriformis 524 
Obturator Internus 525 
Gemelli 526 
Gemellus Superior 526 
Gemellus Inferior 527 
Quadratus Femoris 527 
Obturator Externus 528 
Surgical Anatomy 528 
The Posterior Femoral Region .... 529 
Dissection 529 
Biceps or Biceps Flexor Cruris . . . 529 
Semitendinosus 530' 
Semimembranosus 530 
Surgical Anatomy 531 
Muscles and Fasciae of the Leg. 
The Anterior Tibio-fibular Region . . .531 
Dissection 532 
Deep Fascia of the Leg 532 
Tibialis Anticus 532 
Extensor Proprius Hallucis .... 532 
Extensor Longus Digitorum . . . 533 
Peroneus Tertius 534 
The Posterior Tibio-fibular Region . . 534 
Dissection 534 
The Superficial Layer 534 
Gastrocnemius 534 
Soleus 535 
Tendo-Achillis 535 
The Deep Layer 537 
Dissection 537 
Deep Transverse Fascia . . . 537 
Popliteus 537 
Flexor Longus Hallucis . . . 538 
Flexor Longus Digitorum . . . 538 
Tibialis Posticus 538 
The Fibular Region 539 
Dissection 539 
Peroneus Longus 539 
Peroneus Brevis 540 
Surgical Anatomy of Tendons around Ankle 541 
Muscles and Fasciae of the Foot. 
Dissection 541 
Anterior Annular Ligament 541 
Internal Annular Ligament 542 
External Annular Ligament 542 
Dissection of the Sole of the Foot . 542 
Plantar Fascia 542 
Central Portion of Plantar Fascia . 542 
Lateral Portions of Plantar Fascia 543 
Bursae about the Ankle and Foot . 543 
Surgical Anatomy 543 
The Dorsal Region 543 
Fascia 543 
Extensor Brevis Digitorum .... 543 
The Plantar Region 544 
The First Layer 544 
Dissection 544 
Abductor Hallucis 544 
Flexor Brevis Digitorum . . 544 
Fibrous Sheaths of the Flexor 
Tendons 545 
Abductor Minimi Digiti . . . 545- CONTENTS 
XV 
PAGE 
The Plantar Region- 1 
The Second Layer . .7 7 7 . 546 
Flexor Accessorius 546 
Lumbricales 546 
The Third Layer 546 
Flexor Brevis Hallucis .... 546 
Adductor Obliquus Hallucis . . 546 
Flexor Brevis Minimi Digiti . . 547 
Adductor Transversus Hallucis . 548 
PAGE 
The Plantar Region- 
The Fourth Layer 548 
Interossei Muscles 548 
Dorsal Interossei .... 548 
Plantar Interossei 548 
Surface Form of Muscles of the Lower Ex- 
tremity 549 
Surgical Anatomy of Muscles of the Lower 
Extremity 551 
THE BLOOD-VASCULAR SYSTEM. 
The Circulation of the Blood .... 555 
The Cavity of the Thorax 556 
The Upper Opening of the Thorax . . . 556 
The Lower Opening of the Thorax . . . 556 
The Pericardium. 
Structure of the Pericardium .... 558 
Fibrous Layer 558 
Serous Pericardium 560 
Arteries of the Pericardium . . .561 
Nerves of the Pericardium .... 561 
The Vestigial Fold of the Pericardium 561 
Surgical Anatomy of the Pericardium . . 561 
The Heart. 
Position of the Heart 562 
Size and Weight of the Heart .... 564 
Capacity of the Cavities of the Heart . . 564 
Fat upon the Heart 564 
Component Parts of the Heart .... 565 
Right Auricle 565 
Left Auricle 568 
Right Ventricle 569 
Left Ventricle 571 
Structure of the Heart 574 
Endocardium 574 
Myocardium 574 
Muscular Structure of the Heart . . 575 
Fibres of the Auricles . . . .575 
Fibres of the Ventricles . . 575 
Vessels and Nerves of the Heart . . . 577 
Surface Form of the Heart 577 
Surgical Anatomy of the Heart .... 578 
Peculiarities of Vascular System in Foetus. 578 
The Foramen Ovale 578 
The Eustachian Valve 578 
The Ductus Arteriosus 579 
The Umbilical Arteries 579 
Foetal Circulation 579 
Changes in the Vascular System at Birth . 581 
THE ARTERIES. 
Distribution of the Arteries 7 7 7 . . 583 
Anastomosis of the Arteries ..... 583 
Histology of the Capillaries and Arteries . 584 
Blood-vessels of the Blood-vessel Wall . 586 
Lymphatics of Arteries 586 
Nerves of Arteries 586 
Arterial Sheath 586 
Pulmonary Artery. 
Right Pulmonary Artery 587 
Left Pulmonary Artery 587 
The Aorta. 
The Ascending Aorta. 
Relations of the Ascending Aorta . . . 589 
Branches of the Ascending Aorta . . 590 
The Coronary Arteries 590 
Right Coronary Artery 590 
Left Coronary Artery 590 
Peculiarities of Coronary Arteries . 591 
The Arch of the Aorta. 
Relations of the Arch of the Aorta . . . 591 
Peculiarities of the Arch of the Aorta . 591 
Surgical Anatomy of the Arch of the Aorta 592 
Branches of the Arch of the Aorta . . 593 
Peculiarities of the Branches . . . 593 
The Innominate Artery 593 
Relations 593 
Branches 594 
Thyroidea Ima 594 
Peculiarities 594 
Surgical Anatomy 594 
Arteries of the Head and Neck. 
The Common Carotid Artery. 
Relations of the Common Carotid Artery . 596 
Peculiarities of the Common Carotid Artery 598 
Surface Marking of the Common Carotid 
Artery 598 
Surgical Anatomy of the Common Carotid 
Artery 598 
The External Carotid Artery .... 600 
Relations 600 
Surface Marking 601 
Surgical Anatomy 601 
Branches 601 
Superior Thyroid Artery . .601 
Branches 602 
Surgical Anatomy .... 603 
Lingual Artery 603 
Relations 603 
Branches 603 
Surgical Anatomy .... 604 
Facial or External Maxillary Artery 604 
Relations 605 
Branches 605 
Peculiarities 607 
Surgical Anatomy .... 607 
Occipital Artery 608 
Branches 609 
Posterior Auricular Artery 609 
Branches 610 
Ascending Pharyngeal Artery . 610 
Branches 610 
Surgical Anatomy . . . . 611 
Superficial Temporal Artery . . 611 
Branches 611 
Surgical Anatomy . . . 612 
Internal Maxillary Artery . . .612 
Branches of First Portion . 613 
Surgical Anatomy . 614 
Branches of Second Portion . 614 
Branches of Third Portion . 615 
Surgical Anatomy . 615 
Surgical Anatomy of the Triangles of the 
Neck 616 
Anterior Triangle of the Neck . 616 
Posterior Triangle of the Neck . 618 XVI 
CONTENTS 
PAGE 
The Internal Carotid Artery 619 
Cervical Portion 620 
Relations 620 
Petrous Portion 620 
Cavernous Portion 621 
Cerebral Portion 621 
Peculiarities 621 
Surgical Anatomy 621 
Branches 621 
Tympanic 622 
Arterise Receptaculi .... 622 
Anterior Meningeal .... 622 
Ophthalmic . 622 
Branches 622 
Anterior Cerebral 626 
Branches 626 
Middle Cerebral 627 
Branches 628 
Posterior Communicating . . . 628 
Anterior Choroid 628 
The Bloodvessels of the Brain. 
The Central Ganglionic System .... 630 
The Cortical Arterial System . . . .631 
Arteries of the Upper Extremity. 
The Subclavian Artery. 
First Part of the Right Subclavian Artery . 632 
Relations 632 
First Part of the Left Subclavian Artery . 633 
Relations 633 
Second and Third Parts of Subclavian Artery 633 
Relations ......... 634 
Third Portion of the Subclavian Artery . 634 
Peculiarities of the Subclavian Artery . . 635 
Surface Marking of the Subclavian Artery . 635 
Surgical Anatomy of the Subclavian Artery 635 
Branches of the Subclavian Artery . . .637 
Vertebral Artery 637 
Relations 637 
Branches 638 
Surgical Anatomy 639 
Basilar Artery 639 
Branches 639 
Circle of Willis 640 
Thyroid Axis 640 
Branches 641 
Internal Mammary Artery .... 643 
Relations 644 
Branches 644 
Surgical Anatomy 644 
Superior Intercostal Artery .... 645 
Deep Cervical Branch . . . ,. 645 
Surgical Anatomy of the Axilla .... 645 
Boundaries 645 
Contents 646 
Surgical Anatomy 646 
The Axillary Artery. 
Relations of the Axillary Artery . . . 648 
Peculiarities of the Axillary Artery . . 649 
Surface Marking of the Axillary Artery 649 
Surgical Anatomy of the Axillary Artery . 649 
Branches of the Axillary Artery . . 650 
Superior Thoracic Artery .... 650 
Acromial Thoracic Artery or Thoracic 
Axis 651 
Branches 651 
Long Thoracic or External Mammary 
Artery 651 
Alar Thoracic Artery 651 
Subscapular Artery 651 
Circumflex Arteries 651 
The Brachial Artery. 
Relations of the Brachial Artery . . . 652 
Surgical Anatomy of the Bend of the Elbow 653 
Peculiarities of the Brachial Artery . . 653 
Surface Marking of the Brachial Artery . 654 
Surgical Anatomy of the Brachial Artery . 654 
PAGE 
Branches of the Brachial Artery . . . 655 
Superior Profunda Artery .... 655 
Nutrient Artery 656 
Inferior Profunda Artery .... 656 
Anastomotica Magna 656 
Muscular Branches 656 
The Anastomosis around the Elbow-joint 657 
The Radial Artery 657 
Relations 657 
The Deep Palmar Arch 658 
Peculiarities 658 
Surface Marking 658 
Surgical Anatomy 658 
Branches 659 
Radial Recurrent 659 
Muscular Branches 659 
Anterior Radial Carpal . . . 659 
Superficialis Voise 659 
Posterior Radial Carpal . . . 659 
Dorsalis Pollicis 659 
Dorsalis Indicis 659 
Princeps Pollicis 660 
Radialis Indicis 660 
Perforating Arteries .... 660 
Palmar Interosseous .... 660 
Palmar Recurrent Branches . . 660 
The Ulnar Artery 660 
Relations . . . 661 
Peculiarities 661 
Surface Marking 661 
Surgical Anatomy 661 
Branches 662 
Anterior Ulnar Recurrent . . 662 
Posterior Ulnar Recurrent . . 662 
Interosseous Artery .... 662 
Muscular Branches 663 
Anterior Carpal 663 
Posterior Carpal 663 
Deep Palmar Arch 664 
Superficial Palmar Arch . 664 
Relations 664 
Branches • 664 
Surface Marking .... 665 
Surgical Anatomy .... 665 
Arteries of the Trunk. 
The Descending Aorta. 
The Thoracic Aorta 665 
Relations 665 
Surface Marking - • . . 666 
Surgical Anatomy 666 
Branches 666 
Bronchial Arteries 666 
(Esophageal Arteries .... 666 
Pericardiac Arteries .... 666 
Posterior Mediastinal Arteries 666 
Intercostal Arteries and Branches 667 
Surgical Anatomy .... 668 
The Abdominal Aorta 668 
Relations 669 
Surface Marking 670 
Surgical Anatomy 670 
Branches 671 
The Coeliac Axis or Artery . . 671 
Relations 671 
Branches 671 
Surgical Anatomy . . . .674 
The Superior Mesenteric Artery 675 
Branches '. . . . . .675 
Blood-supply of the Right Iliac 
Fossa 676 
The Inferior Mesenteric Artery . 677 
Suprarenal Artery 678 
The Renal Arteries .... 678 
The Spermatic Arteries . . . 679 
The Ovarian Arteries .... 680 
The Inferior Phrenic Arteries . . 680 
The Lumbar Arteries .... 680 
Branches 681 CONTENTS 
XVII 
PAGE 
The Common Iliac Arteries. 
Branches of Common Iliac Arteries . . 682 
Peculiarities of Common Iliac Arteries. . 682 
Surface Marking of Common Iliac Arteries 682 
Surgical Anatomy of Common Iliac Arteries 682 
The Internal Iliac Artery 683 
Relations 683 
Peculiarities 685 
Surgical Anatomy 685 
Branches 686 
Superior Vesical Artery . . . 686 
Middle Vesical Artery .... 686 
Inferior Vesical Artery .... 686 
Middle Haemorrhoidal Artery . 687 
Uterine Artery 687 
Vaginal Artery 687 
Surgical Anatomy .... 688 
Obturator Artery 688 
Branches 688 
Peculiarities 689 
Internal Pudic Artery .... 689 
Relations 690 
Peculiarities 690 
Surgical Anatomy .... 690 
Branches 690 
Sciatic Artery 692 
Branches 693 
Lateral Sacral Artery .... 693 
Branches 693 
Gluteal Artery 694 
Branches 694 
Surface Marking .... 694 
Surgical Anatomy .... 694 
The External Iliac Artery 694 
Relations 694 
Surface Marking 695 
Surgical Anatomy 695 
Branches 696 
Internal or Deep Epigastric Artery 696 
Branches 696 
Peculiarities 696 
Surgical Anatomy .... 697 
Deep Circumflex Iliac Artery . . 697 
Arteries of the Lower Extremity. 
The Femoral Artery. 
Scarpa's Triangle . 697 
Hunter's Canal or the Adductor Canal . 698 
The Common Femoral Artery . . . ,. 699 
Relations 700 
The Superficial Femoral Artery .... 700 
Relations 700 
Peculiarities 700 
Surface Marking 701 
Surgical Anatomy 701 
Branches 704 
Superficial Epigastric . . . .704 
Superficial Circumflex Iliac . . 704 
Superficial External Pudic . 704 
Deep External Pudic .... 704 
Deep Femoral or Profunda Femoris 704 
Relations 704 
Branches 705 
PAGE 
The Superficial Femoral Artery- 
Muscular Branches 707 
Anastomotica Magna .... 707 
Branches 707 
The Popliteal Artery. 
The Popliteal Space 707 
Dissection 707 
Boundaries 707 
Position of Contained Parts . . .708 
Peculiarities 70C 
Surface Marking 709 
Surgical Anatomy . . . . . . 709 
Branches 710 
Superior Muscular Branches . . 710 
Inferior Muscular Branches . . 710 
Cutaneous Branches . . . . 710 
Superior Articular Arteries . . 710 
Azygos Articular Artery . . . 711 
Inferior Articular Arteries . . . 711 
Circumpatellar Anastomosis . . 711 
The Anterior Tibial Artery . . . . . 711 
Relations 711 
Peculiarities 712 
Surface Marking 712 
Surgical Anatomy 712 
Branches 712 
Posterior Recurrent Tibial . . 713 
Superior Fibular 713 
Anterior Recurrent Tibial . . . 713 
Muscular Branches 713 
Malleolar Arteries 713 
The Dorsalis Pedis Artery 714 
Relations 714 
Peculiarities 715 
Surface Marking 715 
Surgical Anatomy 715 
Branches 715 
Cutaneous Branches .... 715 
Tarsal Artery 715 
Metatarsal Artery 715 
Communicating Artery . . . 716 
The Posterior Tibial Artery 716 
Relations 716 
Peculiarities 717 
Surface Marking 717 
Surgical Anatomy 717 
Branches 717 
Peroneal Artery 717 
Relations 718 
Peculiarities 718 
Branches 718 
Cutaneous Branches .... 718 
Nutrient Artery 719 
Muscular Branches 719 
Communicating Branch . 719 
Malleolar or Internal Malleolar 
Artery 719 
Internal Calcanean Arteries . . 719 
Internal Plantar Artery . . .719 
External Plantar Artery . . . 720 
Surface Marking . . . .720 
Surgical Anatomy .... 720 
Branches 720 
THE VEINS. 
Subdivisions of the Veins 721 
Anastomosis of Veins 722 
Histology of the Veins 723 
The Superficial or Cutaneous Veins . . . 723 
The Deep Veins 723 
The Pulmonary Veins. 
The Systemic Veins. 
Veins of the Head and Neck.' 
Veins of the Exterior of the Head and Face 725 
Veins of the Exterior of the Head and Face- 
Frontal Vein 725 
Supraorbital Vein 726 
Angular Vein 726 
Anterior Facial Vein 726 
Common Facial Vein 726 
Superficial Temporal Vein .... 727 
The Pterygoid Plexus and the Internal 
Maxillary Vein 727 
Temporo-maxillary Vein .... 727 
Posterior Auricular Vein .... 727 
Occipital Vein 727 XVIII 
CONTENTS 
PAGE 
'.The Veins of the Neck 728 
External Jugular Vein 728 
Posterior External Jugular Vein 728 
Anterior Jugular Vein 728 
Internal Jugular Vein 729 
Lingual Veins 729 
Pharyngeal Veins 730 
Superior Thyroid Vein .... 730 
Middle Thyroid Vein .... 730 
Veins of the Thyroid Gland . . 731 
Surgical Anatomy 732 
Vertebral Vein 732 
Anterior Vertebral or Anterior 
Deep Cervical Vein .... 733 
Posterior Vertebral or Posterior 
Deep Cervical Vein .... 733 
'The Veins of the Diploe 733 
The Meningeal Veins 734 
The Cerebral Vein 734 
Superficial or Cortical Cerebral Veins . 735 
Superior Cerebral Veins . . . 735 
Median Cerebral Veins .... 735 
Inferior Cerebral Veins . 735 
Deep Cerebral, Central or Ventricular 
Veins, Veins of Galen . . . 735 
Vena Corporis Striati .... 735 
Choroid Vein 735 
Basilar Vein 735 
Superficial Cerebellar Veins .... 736 
Deep Cerebellar Veins 736 
Veins of the Pons Varoli . 736 
Veins of the Medulla Oblongata . 736 
The Sinuses of the Dura Mater, Ophthalmic 
Veins and Emissary Veins . . . 736 
Superior Longitudinal Sinus . . . 736 
Torcular Herophili 737 
Inferior Longitudinal Sinus .... 738 
Straight Sinus 738 
Lateral Sinus 738 
Surgical Anatomy 739 
Occipital Sinus 739 
Cavernous Sinus 739 
Surgical Anatomy 740 
Spheno-parietal Sinus or Sinus Al® 
Parv® 740 
Ophthalmic Veins - 740 
Circular Sinus 742 
Superior Petrosal Sinus 742 
Inferior Petrosal Sinus 742 
Transverse or Basilar Sinus . . 743 
Emissary Veins 743 
Surgical Anatomy . . . .743 
Veins of the Upper Extremity and Thorax. 
The Superficial Veins of Upper Extremity . 745 
Superficial Veins of the Hand and Fin- 
gers 745 
Anterior Ulnar Vein 745 
Posterior or Dorsal Ulnar Vein . . 745 
Common Ulnar Vein 745 
Radial Vein 745 
Median Vein 745 
Median Cephalic Vein 746 
Median Basilic Vein . .746 
Basilic Vein 746 
Cephalic Vein 747 
The Deep Veins of the Upper Extremity . 747 
Interosseous Veins 747 
Deep Palmar Veins 747 
Brachial Veins . 747 
Axillary Vein 747 
Branches 748 
Surgical Anatomy ...... 748 
Subclavian Vein 749 
Innominate or Brachio-cephalic Veins 750 
Right Innominate Vein 750 
Left Innominate Vein . 750 
Peculiarities . . . 750 
PAGE 
The Deep Veins of the Upper Extremity- 
Internal Mammary Vein 750 
Inferior Thyroid Veins 751 
Intercostal Veins 752 
Superior Vena Cava 752 
Relations 752 
Azygos Veins 752 
Surgical Anatomy 753 
Bronchial Veins 753 
The Spinal Veins 753 
Dorsi-spinal Veins 753 
Meningo-rachidian Veins .... 754 
Veins of the Bodies of the Vertebrae or 
Venae Basis Vertebrarum .... 755 
Veins of the Spinal Cord or Medulli- 
spinal Veins 755 
Veins of the Lower Extremity, Abdomen 
and Pelvis. 
The Superficial Veins of the Lower Extrem- 
ity 756 
The Superficial Veins of the Foot . 756 
Internal or Long Saphenous Vein . 756 
External or Short Saphenous Vein 756 
Surgical Anatomy 757 
The Deep Veins of the Lower Extremity . 758 
The Deep Veins of the Foot . .758 
Posterior Tibial Veins 758 
Anterior Tibial Veins : 758 
Popliteal Vein 758 
Femoral Vein 758 
External Iliac Vein 759 
Deep Epigastric Vein 759 
Deep Circumflex Iliac Vein 759 
Hypogastric or Internal Iliac Vein . 760 
Surgical Anatomy 761 
Obturator Vein 761 
Sciatic Veins 761 
Gluteal Veins 761 
Superior Vesical Plexus .... 761 
Prostatic or Prostatico-vesical Plexus . 761 
Inferior Vesical Plexus 762 
Surgical Anatomy 762 
The Dorsal Veins of the Penis . . 762 
The Vaginal Plexuses and Veins . 763 
The Uterine Plexuses and Veins 763 
Common Iliac Vein 764 
Peculiarities 764 
Ascending or Inferior Vena Cava . 764 
Relations 764 
Peculiarities 764 
Lumbar Veins 765 
Spermatic Veins 765 
Surgical Anatomy . . 766 
Ovarian Veins 766 
Renal Veins 767 
Suprarenal Veins 767 
Phrenic Veins 767 
Hepatic Veins 767 
The Portal System of Veins. 
Superior Mesenteric Vein 768 
Splenic Vein 768 
Inferior Mesenteric Vein 768 
Gastric Veins 768 
Cystic Vein 769 
Portal Vein 769 
The Cardiac Veins. 
Great Cardiac or Left Coronary Vein . . 770 
Posterior or Middle Cardiac Vein .771 
Left Cardiac Vein 771 
Anterior Cardiac Vein 771 
Right Cardiac or Small Coronary Vein . 771 
Coronary Sinus 771 
Ven® Thebesii 771 CONTENTS 
XIX 
THE LYMPHATIC SYSTEM. 
PAGE 
Subdivision into Superficial and Deep Sets 773 
Lymphatic or Conglobate Glands . . . 774 
The Thoracic Duct and the Right 
Lymphatic Duct. 
Radicals of Origin and Tributaries of Tho- 
racic Duct 777 
Structure of the Thoracic Duct .... 778 
The Right Lymphatic Duct 778 
Tributaries 779 
Lymphatics of the Cranial Region, Face 
and Neck. 
The Lymphatic Glands of the Head and 
Face 780 
The Occipital or Suboccipital Glands . 780 
The Posterior Auricular, Retro-auricu- 
lar or Mastoid Glands .... 780 
Parotid Lymph Glands 781 
The Subparotid Glands 782 
The Internal Maxillary or Zygomatic 
Glands 782 
The Facial Glands or Genial Glands . 782 
The Lymphatic Vessels of the Cranial Region 782 
The Lymphatic Vessels of the Face, the In- 
terior of the Nose, Tongue, Floor of the 
Mouth, Pharynx, Larynx and Thyroid 
Gland 782 
The Lymphatic Glands of the Neck . 784 
The Superficial Cervical Glands . 784 
The Submaxillary or Lateral Supra- 
hyoid Glands . . ... . . . 784 
The Submental or Median Suprahyoid 
Glands 785 
The Retro-pharyngeal or Post-pharyn- 
geal Glands 785 
The Deep Cervical, Carotid, or Sterno- 
mastoid Glands 786 
The Lymphatic Vessels of the Neck . 787 
Surgical Anatomy 787 
The Lymphatics of the Upper Extremity. 
The Lymphatic Glands of the Upper Ex- 
tremity 788 
The Superficial Lymphatic Glands . 788 
The Deep Lymphatic or the Axillary 
Glands 790 
The Lymphatic Vessels of the Upper Ex- 
tremity 792 
The Superficial Lymphatic Vessels of 
the Upper Extremity 792 
The Deep Lymphatic Vessels of the 
Upper Extremity .... 792 
Surgical Anatomy 792 
The Lymphatics of the Lower Extremity. 
The Lymphatic Glands of the Lower Ex- 
tremity 793 
The Superficial Inguinal Lymphatic 
Glands 793 
Surgical Anatomy 794 
The Deep Lymphatic Glands of the 
Lower Extremity .... 795 
The Deep Inguinal or Deep Fem- 
oral Lymphatic Glands . . . 795 
The Anterior Tibial Gland . . 795 
The Popliteal Glands .... 795 
The Gluteal and Ischiatic Glands 797 
The Lymphatic Vessels of the Lower Ex- 
tremity 797 
The Superficial Lymphatic Vessels of 
the Lower Extremity 797 
The Deep Lymphatic Vessels of the 
Lower Extremity 797 
PAGE 
The Lymphatics of the Pelvis and 
Abdomen. 
The Iliac or Ilio-pelvic Glands .... 797 
The External Iliac Glands .... 797 
The Internal Iliac or Hypogastric Glands 799 
The Common Iliac Gland .... 799 
The Abdomino-aortic Glands .... 799 
The Right Juxta-aortic Glands 800 
The Left Juxta-aortic Glands . . 800 
The Retro-aortic Glands .... 800 
The Pre-aortic Glands 800 
The Glands along the Mesenteric 
Arteries 800 
The Glands connected with the 
Cceliac Axis and its Branches . 800 
The Gastric Glands 800 
The Splenic Glands 800 
The Hepatic Glands . . . .801 
The Lymphatic Vessels of the Abdomen and 
Pelvis 801 
The Superficial Lymphatic Vessels of 
the Walls of the Abdomen . . 801 
The Superficial Lymphatic Vessels 
of the Gluteal Region . . .801 
The Superficial Lymphatic Vessels 
of the Scrotum and Perinaeum . 801 
The Superficial Lymphatic Vessels 
of the Penis 801 
The Deep Lymphatic Vessels of the 
Abdominal Wall 801 
The Lymphatic Vessels of the Um- 
bilicus 802 
The Lymphatic Vessels of the Peri- 
toneum 802 
The Lymphatic Vessels of the 
Bladder 802 
The Lymphatic Vessels of the Pros- 
tate Gland 803 
The Lymphatic Vessels of the Male 
Urethra 803 
The Lymphatic Vessels of the Fe- 
male Urethra 803 
The Lymphatic Vessels of the 
Uterus 803 
The Lymphatic Vessels of the Fal- 
lopian Tube 804 
The Lymphatic Vessels of the 
Ovary 804 
The Lymphatic Vessels of the 
Vagina 804 
The Lymphatic Vessels of the 
Testicle 804 
The Lymphatic Vessels of the 
Vas Deferens . . . . . 804 
The Lymphatic Vessels of the 
Seminal Vesicles 804 
The Lymphatic Vessels of the 
Kidney, Ureter, and Suprarenal 
Capsule 804 
The Lymphatic Vessels of the Liver 805 
The Lymphatic Vessels of the 
Bile-ducts 806 
The Lymphatic Vessels of the 
Stomach 806 
The Lymphatic Vessels of the 
Pancreas 807 
The Lymphatic Vessels of the 
Spleen 807 
The Lymphatic System of the Intestines. 
The Lymphatic Glands of the Small Intestine 807 
The Lymphatic Vessels of the Small Intestine 808 
The Lymphatic Glands of the Large Intestine 808 
The Colic Glands 808 
The Rectal Glands 809 XX 
CONTENTS 
PAGE 
The Lymphatic Vessels of the Large Intestine 809 
Lymphatics of the Anus and Rectum . 809 
The Lymphatics of the Thorax. 
The Lymphatic Glands of the Thoracic Wall 
or the Parietal Lymphatics . . . 810 
The Internal Mammary Glands . . 810 
The Intercostal Glands 810 
The Diaphragmatic Lymphatics . . 810 
The Visceral Lymphatics .811 
The Anterior Mediastinal Glands . 811 
The Posterior Mediastinal Glands 812 
The Peritracheo-bronchial Glands 812 
The Lymphatic Vessels of the Thoracic Wall 812 
The Cutaneous Lymphatics 812 
Lymphatics of the Mammary Gland 812 
Lymphatics of the Great Pectoral 
Muscle 814 
Surgical Anatomy 814 
The Pulmonary Lymphatics . 815 
The Pleural Lymphatics . . 815 
The Cardiac Lymphatics . . . . 815 
The Thymic Lymphatic Vessels . 815 
The Lymphatic Vessels of the (Esoph- 
agus 815 
The Lymphatic Vessels of the Thoracic 
Trachea 815 
THE NERVOUS SYSTEM. 
Structure of the Cerebro-spinal Nervous 
System 817 
Nerve-cells or the Cell-bodies of the 
Neurones 818 
Unipolar cells 820 
Bipolar cells 820 
Multipolar cells 821 
The Axone 821 
The Dendrites 821 
The Theory of Neurones . . . .821 
Nerve-fibres 822 
Development of Nerve-cells and Fibres . 823 
Chemical Composition of Nervous Tissue . 824 
Origin and Termination of Nerves . 826 
Peripheral Termination of Nerves . 826 
Termination in Fibrillae 827 
Neuro-tendinous Spindles .... 829 
Neuro-muscular Spindles .... 829 
The Cerebro-spinal Axis. 
The Spinal Cord and its Membranes. 
Dissection 832 
Membranes of the Cord. 
The Spinal Dura Mater 832 
Structure 834 
The Arachnoid Membrane 834 
Structure 834 
The Pia Mater of the Cord 835 
Structure 835 
Surgical Anatomy 836 
The Spinal Cord. 
Fissures and Grooves 837 
Columns of the Cord 838 
Structures of the Cord 839 
Blood Supply of the Cord 840 
Minute Anatomy of the Cord .... 840 
The Meninges or Meningeal Membranes of 
the Brain. 
Dissection 847 
The Dura Mater of the Brain .... 847 
Structure 848 
Processes of the Dura Mater . . . 849 
The Arachnoid Membrane 851 
The Subarachnoid Space .... 852 
Structure 853 
Glandulae Pacchioni, Luschka's Villi or the 
Arachnoid Villi 854 
The Pia Mater of the Brain 854 
The Velum Interpositum or the Tela 
Chorioidea Superior 854 
The Brain. 
The Development of the Brain .... 857 
General Considerations and Divisions . . 864 
The Hemispheres of the Cerebrum . 864 
The Constituent Parts of the Hemi- 
sphere 864 
The Hemispheres of the Cerebrum- 
The Surface of the Cerebrum . 865 
Fissures and Sulci of the Outer Surface 
of the Hemisphere 865 
The Lobes on the External Surface 869 
The Fissures, Sulci and Lobes of the 
Mesial and Tentorial Surfaces 869 
The Frontal Lobe 872 
The Parietal Lobe 875 
The Occipital Lobe 876 
The Temporal Lobe 877 
The Central Lobe or Island of Reil 
(Insula) 878 
Limbic Lobe 878 
The Olfactory Lobe or Rhinencephalon 880 
Under Surface or Base of Encephalon . 881 
General Arrangement of the Parts 
composing the Cerebrum .... 885 
Fibres of the Internal Capsule . 892 
The Inter-brain 901 
The Third Ventricle 901 
The Optic Thalamus 903 
The Pineal Body, Epiphysis Cerebri, 
Conarium or Pineal Gland . 905 
The Mid-brain 906 
Crusta or Pes 907 
The Tegmentum 908 
The Substantia Nigra 910 
The Corpora or Tubercula Quadri- 
gemina 911 
The Corpora Geniculata 911 
The Aqueduct of Sylvius or Iter a Tertio 
ad Quartuni Ventriculum 912 
Subthalamic region 913 
Structure of the Cerebrum . 913 
The Hind-brain 922 
Pons Varolii 923 
The Cerebellum or Little Brain 926 
The Medulla Oblongata 938 
The Pyramid 939 
The Lateral Column or Lateral Area . 940 
The Olive, Olivary Body or Olivary 
Eminence 941 
The Funiculus or Fasciculus of Ro- 
lando 941 
The Cuneate Fasciculus . . .941 
The Fasciculus Gracilis 941 
The Restif onn Body 941 
The Posterior Surface of the Medulla 
Oblongata 942 
The Fourth Ventricle 942 
The Roof or Posterior Wall 943 
The Floor or Anterior Wall 944 
The Internal Structure of the Medulla 
Oblongata 945 
The Posterior Area .... 946 
The Lower Part of the Medulla 946 
The Upper Part of the Medulla 948 
Cerebral Localization and Topography. 
Cranio-cerebral Topography 954 CONTENTS 
XXI 
PAGE 
The Nerve-paths. 
The Motor, Efferent or Descending Tract . 959 
The Sensory, Afferent or Ascending Tract . 961 
The Spinal Nerves. 
The Roots of the Spinal Nerves . . . 965 
The Anterior or Ventral Root . 965 
The Posterior or Dorsal Root . . 965 
The Ganglia of the Spinal Nerves . . . 966 
Distribution of the Spinal Nerves . 967 
Points of Emergence of the Spinal Nerve . 967 
The Cervical 'Nerves. 
The Roots of the Cervical Nerves . . 968 
The Posterior or Dorsal Division of the 
Cervical Nerves 968 
The Anterior Division of the Cervical Nerves 971 
The Cervical Plexus 972 
Superficial Branches 972 
Deep Branches, Internal Series . 974 
Surgical Anatomy 976 
Deep Branches, External Series . 976 
Surgical Anatomy 977 
The Brachial Plexus 977 
Relations 980 
Branches 981 
Surgical Anatomy 991 
The Thoracic or Dorsal Nerves. 
The Roots of the Thoracic or Dorsal Nerves 993 
The Posterior Divisions of the Thoracic or 
Dorsal Nerves 993 
The Internal Branches 993 
The External Branches 993 
The Cutaneous Branches .... 993 
The Anterior Divisions of the Thoracic or 
Dorsal Nerves or the Intercostal 
Nerves 993 
The Anterior Division of the First 
Thoracic or First Dorsal Nerve . . 995 
The Anterior Divisions of the Upper 
Thoracic or Dorsal Nerves . . . 995 
The Anterior Divisions of the Lower 
Thoracic or Dorsal Nerves . 996 
The Last Thoracic or Dorsal Nerve . 996 
Surgical Anatomy 996 
The Lumbar Nerves. 
The Roots of the Lumbar Nerves . . 997 
The Posterior Divisions of the Lumbar 
Nerves 997 
Internal Branches 998 
External Branches 998 
The Anterior Divisions of the Lumbar Nerves 998 
The Lumbar Plexus 998 
Branches 999 
The Sacral and Coccygeal Nerves. 
The Roots of the Upper Sacral Nerves . 1006 
The Posterior Divisions of the Sacral Nerves 1006 
The Upper Sacral Nerves .... 1006 
The Lower Sacral Nerves .... 1007 
The Anterior Divisions of the Sacral Nerves 1007 
The Posterior Divisions of the Coccygeal 
Nerve . 1008 
The Anterior Division of the Coccygeal 
Nerve 1009 
The Sacral or Sciatic Plexus and the Pudic 
or Pudendal Plexus 1009 
Branches 1010 
Surgical Anatomy 1017 
The Cerebral or Cranial Nerves. 
The First or Olfactory Nerve. 
Surgical Anatomy 1021 
PAGE 
The Second or Optic Nerve. 
The Optic Tract 1021 
The Optic Commissure 1021 
The Optic Path 1022 
Surgical Anatomy 1022 
The Third or Motor Ocidi Nerve. 
Surgical Anatomy 1025 
The Fourth or Trochlear Nerve. 
Branches of Communication 1026 
Branches of Distribution 1026 
Surgical Anatomy . . . 1026 
The Fifth, Trigeminal or Trifacial Nerve. 
The Gasserian or Semilunar Ganglion . . 1027 
Ophthalmic Nerve 1028 
Branches 1028 
The Superior Maxillary Nerve .... 1031 
Branches 1032 
The Mandibular or Inferior Maxillary Nerve 1036 
Branches 1036 
Surface Marking 1041 
Surgical Anatomy 1041 
The Sixth or Abducent Nerve. 
Branches of Communication 1043 
Surgical Anatomy 1044 
The Seventh or Facial Nerve. 
Branches of Communication 1046 
Branches of Distribution 1046 
Surgical Anatomy 1049 
The Eighth or Auditory Nerve. 
The Origin of the Eighth Nerve . 1050 
The Auditory Paths 1053 
Surgical Anatomy 1054 
The Ninth or Glosso-Pharyngeal Nerve. 
The Superior or Jugular Ganglion . . 1056 
The Inferior or Petrous Ganglion . . 1056 
Branches of Communication . . . 1056 
Branches of Distribution .... 1056 
The Gustatory Path 1056 
Surgical Anatomy 1057 
The Tenth or Pneumogastric Nerve. 
The Ganglion of the Root of the Pneumo- 
gastric Nerve 1059 
Connecting Branches 1059 
The Ganglion of the Trunk of the Pneumo- 
gastric Nerve 1059 
Connecting Branches 1059 
Surgical Anatomy 1062 
The Eleventh or Spinal Accessory Nerve. 
The Bulbar or Accessory Part of the Spinal 
Accessory Nerve 1063 
The Spinal Portion of the Spinal Accessory 
Nerve 1063 
Surgical Anatomy 1063 
The Twelfth or Hypoglossal Nerve. 
Branches of Communication 1065 
Branches of Distribution 1066 
Surgical Anatomy 1066 
The Sympathetic Nerve. 
Structure of the Sympathetic System . . 1068 
The Gangliated Cord. 
The Cervical Portion of the Gangliated Cord 1071 
The Superior Cervical Ganglion . 1072 
The Inferior Cervical Ganglion . . 1077 
Surgical Anatomy 1077 XXII 
CONTENTS 
PAGE 
The Thoracic Portion of the Gangliated Cord 1078 
The Lumbar Portion of the Gangliated Cord 1079 
The Pelvic or Sacral Portion of the Gangli- 
ated Cord 1080 
The Great Plexuses of the Sympathetics. 
The Cardiac Plexus 1081 
The Great or Deep Cardiac Plexus . 1081 
PAGE 
The Cardiac Plexus- 
The Superficial or Anterior Cardiac 
Plexus 1081 
The Pulmonary Plexus 1081 
The (Esophageal Plexus 1082 
The Epigastric or Solar Plexus .... 1083 
The Hypogastric Plexus 1085 
The Pelvic or Sacral Plexus .... 1086 
THE ORGANS OF SPECIAL SENSE. 
The Tongue. 
The Body 1087 
The Base or Root 1087 
The Apex or Tip 1087 
The Margin of the Tongue 1087 
The Under or Inferior Surface .... 1087 
Structure of the Tongue 1088 
Surgical Anatomy 1093 
The Nose. 
The Outer Nose. 
Structure 1096 
The Nasal Fossce. 
The Anterior Nares 1098 
The Posterior Nares 1098 
Outer Wall 1099 
The Inner Wall 1100 
Surgical Anatomy 1102 
The Eye. 
The Fascia or Capsule of T^non . .1103 
The Tunics of the Eye. 
The Fibrous or External Coat: The Sclerotic 
and Cornea 1107 
The Sclera or Sclerotic Coat . .1107 
The Cornea 1108 
Dissection 1111 
The Choroid, Ciliary Body, and Iris; the 
Tunica Media; the Uveal Tract . . 1111 
The Choroid 1111 
The Ciliary Body 1115 
The Iris 1117 
The Tunica Interna or Retina .... 1120 
The Refracting Media. 
The Aqueous Humor 1128 
The Vitreous Body 1129 
The Crystalline Lens 1130 
Surgical Anatomy of the Eye .... 1134 
The Appendages of the Eye 
The Eyebrow 1137 
The Eyelid 1137 
The Meibomian or Tarsal Glands . 1139 
The Conjunctiva 1140 
The Lachrymal Apparatus 1141 
The Lachrymal Glands 1141 
The Lachrymal Sac 1142 
The Nasal Duct 1142 
Surface Form 1142 
Surgical Anatomy 1143 
The Ear. 
The External Ear. 
The Pinna or Auricle 1144 
Structure of the Pinna 1146 
The External Auditory Canal .... 1148 
The Cartilaginous Portion .1148 
The Osseous Portion 1149 
Surface Form 1150 
The Middle Ear, Drum or Tympanum. 
The Tympanic Cavity 1150 
The Drumhead or Membrana Tympani . 1155 
The Ossicles of the Tympanum .... 1158 
The Malleus or Hammer . . . .1158 
The Incus or Anvil 1159 
The Stapes or Stirrup 1160 
The Internal Ear or Labyrinth. 
The Osseous Labyrinth 1164 
The Vestibule 1164 
The Semicircular Canals .... 1165 
The Cochlea 1165 
The Membranous Labyrinth 1169 
The Utricle 1169 
The Saccule 1170 
The Membranous Semicircular Canals . 1170 
Surgical Anatomy 1176 
The Skin. 
The Corium, Cutis Vera, Dermis or True 
Skin 1180 
The Cuticle, Scarf Skin or Epidermis . . 1181 
The Appendages of the Skin .... 1185 
The Nails 1185 
The Hairs 1187 
The Sudoriferous or Sweat-glands . . 1190 
The Sebaceous Glands 1191 
The Alimentary Canal. 
The. Mouth, Oral or Buccal Cavity. 
The Vestibule 1194 
The Cavity of the Mouth Proper .1194 
The Lips 1194 
The Cheeks 1195 
The Gums 1195 
The Teeth 1195 
General Characters 1195 
Temporary, Deciduous or Milk Teeth . 1196 
Permanent Teeth 1196 
Arrangement of the Teeth . . .1198 
Structure of the Teeth 1290 
Development of the Teeth . .1294 
The Palate 1210 
The Hard Palate 1210 
THE ORGANS OF DIGESTION 
The Palate- 
The Soft Palate or Velum Pendulum 
Palati 1211 
The Tonsil or Amygdala .... 1213 
The Salivary Glands 1214 
The Parotid Gland 1214 
Surface Form 1215 
The Submaxillary Gland .... 1216 
The Sublingual Gland 1217 
Structure of Salivary Glands . . 1217 
Surface Form 1219 
The Pharynx. 
The Nasal Part 1221 
The Oral Part 1221 
The Laryngeal Part 1222 
Structure 1222 CONTENTS 
XXIII 
PAGE 
Surgical Anatomy of the Mouth, Cheeks, 
Lips, Gums, Tonsils, Palate, Salivary 
Glands and Pharynx 1224 
The (Esophagus. 
Relations 1227 
Anomalies 1228 
Structure 1228 
Movements and Innervations of the Oesoph- 
agus 1230 
Surgical Anatomy 1230 
The Abdomen. 
Boundaries 1231 
Development of the Alimentary Canal, Vis- 
cera and Peritoneum 1235 
Development of the Alimentary Canal . . 1236 
The Peritoneum. 
Structure of the Peritoneum .... 1245 
Retro-peritoneal Fossae 1260 
Surgical Anatomy 1264 
The Stomach. 
Relations of the Stomach 1269 
Surfaces 1269 
The Cardia 1270 
The Pylorus 1270 
Alterations in Position 1271 
Supports of the Stomach 1272 
Structure 1273 
Movements and Innervation of Stomach . 1280 
Surface Form 1280 
Surgical Anatomy 1280 
The Small Intestine. 
The Duodenum 1282 
The First or Superior Portion . . . 1284 
The Second or Descending Portion . 1285 
The Third, Pre-aortic, Horizontal or 
Transverse Portion 1285 
The Fourth or Ascending Portion . 1286 
The Jejunum and Ileum 1289 
Differences between the Jejunum and 
Ileum 1289 
The Jejunum 1289 
The Ileum 1289 
Structure of the Small Intestine, including 
the Duodenum 1290 
PAGE 
The Large Intestine. 
The Caecum 1300 
The Vermiform Appendix .... 1303 
The Ileo-csecal Valve or the Valve of 
Bauhin 1308 
The Colon 1309 
The Ascending Colon 1309 
The Transverse Colon 1309 
The Descending Colon 1309 
The Sigmoid Flexure, Pelvic Colon or 
Sigmoid Colon 1311 
The Rectum 1312 
The Common Anal Canal .... 1315 
Structure of the Large Intestine . 1316 
Movements and Innervations of the Intes- 
tines 1322 
Surface Form of the Intestines .... 1323 
Surgical Anatomy of the Intestines . 1324 
The Liver. 
The Superior Area or Surface .... 1327 
The Anterior Area or Surface .... 1327 
The Lateral or Right Area or Surface . . 1329 
The Under or Visceral Area or Surface . 1329 
The Posterior Area or Surface .... 1329 
Fissures of the Liver 1331 
Lobes of the Liver 1332 
Supports and Movability of the Liver . . 1334 
Abnormalities of the Liver 1335 
Structure of the Liver 1337 
The Excretory Apparatus of the Liver . 1342 
The Hepatic Duct 1342 
The Gall-bladder ...... 1342 
The Cystic Duct 1344 
Surface Relations of the Liver .... 1346 
Surgical Anatomy of the Liver .... 1346 
The Pancreas. 
Dissection 1348 
The Right Extremity or Head of the Pan- 
creas 1348 
The Neck of the Pancreas 1350 
The Body and Tail of the Pancreas . 1350 
Structure of the Pancreas 1352 
Surface Form 1353 
Surgical Anatomy 1353 
The Spleen. 
Surface of the Spleen 1354 
Supports and Movability of the Spleen . 1356 
Surface Form 1359 
Surgical Anatomy 1359 
ORGANS OF VOICE AND RESPIRATION. 
The Larynx. 
The Cartilages of the Larynx .... 1362 
The Thyroid Cartilage 1362 
The Cricoid Cartilage 1363 
The Arytenoid Cartilages .... 1364 
The Cornicula Laryngis or Cartilages 
of Santorini 1365 
The Cuneiform Cartilages or Cartilages 
of Wrisberg 1365 
The Epiglottis or the Cartilage of Epi- 
glottis 1365 
Structure of the Larynx 1365 
Interior of the Larynx 1368 
The Trachea and Bronchi. 
Relations 1376 
The Right Bronchus 1376 
The Left Bronchus 1378 
Structure of the Trachea 1378 
Surface Form of Larynx 1380 
Surgical Anatomy of Larynx and Trachea . 1381 
The Pleur.e. 
Reflections of the Pleura 1384 
Structure of the Pleura 1387 
Surgical Anatomy 1387 
The Mediastinal Space, Interpleural Space 
or Mediastinum. 
The Superior Mediastinum 1388 
The Anterior Mediastinum 1389 
The Middle Mediastinum 1389 
The Posterior Mediastinum 1389 
The Lungs. 
Apex of the Lungs 1390 
Base of the Lungs 1391 
Surfaces of the Lungs 1391 
Borders of the Lungs . 1392 
Lobes of the Lungs . 1392 XXIV 
CONTENTS 
PAGE 
The Root of the Lung 1394 
The Foetal Lung 1394 
Structure of the Lung 1394 
The Bronchus 1395 
page 
Changes in the Structure of the Bronchi in 
the Lungs 1395 
Surface Form of the Lungs 1397 
Surgical Anatomy of the Lungs . 1397 
THE DUCTLESS GLANDS. 
The Thyroid Body or Gland. 
Accessory Thyroids 1403 
Structure of the Thyroid 1403 
Surgical Anatomy 1405 
Parathyroids 1406 
Structure of 1406 
The Thymus Gland. 
Structure of the Thymus Gland . . . 1408 
The Carotid Gland or Carotid Body. 
Surgical Anatomy 1409 
The Coccygeal Gland or Coccygeal Body 1410 
THE URINARY ORGANS. 
The Kidneys. 
Surfaces of the Kidneys 1412 
Borders of the Kidneys 1415 
General Structure of the Kdney . 1415 
Surface Form 1425 
Surgical Anatomy 1425 
The Ureter. 
The Ureter Proper 1426 
Relations of the Ureter 1427 
Structure of the Ureter 1427 
Surgical Anatomy 1428 
The Suprarenal Capsule or Gland. 
Relations of the Suprarenal Capsule . 1428 
Accessory Suprarenal Glands .... 1430 
Structure of Suprarenal Glands .... 1430 
The Cavity of the Pelvis. 
Boundaries 1431 
Contents 1431 
The Urinary Bladder. 
Surfaces 1433 
The Fundus or Base 1433 
The Summit or Apex 1435 
The Urachus or Middle Umbilical Ligament 1435 
Structure of the Bladder 1437 
Objects Seen on the Inner Surface of Bladder 1438 
Surface Form 1440 
Surgical Anatomy 1440 
The Male Urethra. 
The First or Prostatic Portion .... 1441 
The Second, Muscular or Membranous Por- 
tion 1442 
The Third, Penile, Pendulous, Cavernous or 
Spongy Portion 1443 
Structure of Male Urethra 1444 
Surgical Anatomy 1445 
The Female Bladder and Urethra. 
The Female Urethra 1446 
Structure 1446 
THE MALE ORGANS OF GENERATION. 
The Prostate Gland. 
The Base 1451 
The Apex 1451 
Surfaces 1451 
The Lateral Lobes 1451 
The So-called Middle Lobe 1451 
Structure 1452 
Surgical Anatomy 1452 
Cowper's Glands. 
Structure 1453 
The Penis. 
The Root 1454 
The Body of the Penis 1455 
Structure of the Penis 1455 
Surgical Anatomy 1460 
The Testicles and their Coverings. 
Descent of the Testis. 
Surgical Anatomy 1462 
The Coverings of the Testicle. 
The Testicular Bag or Scrotum .... 1462 
The Intercolumnar or Spermatic Fascia . 1463 
The Cremasteric Fascia 1464 
The Infundibuliform Fascia 1464 
The Tunica Vaginalis 1465 
The Spermatic Cord. 
Structure 1466 
Surgical Anatomy 1468 
The Testicles. 
Structure of the Testicle and Epididymis . 1471 
Surgical Anatomy 1473 
The Seminal Vesicles. 
The Ejaculatory Ducts 1476 
Structure 1476 
THE FEMALE ORGANS OF GENERATION. 
External Organs. 
The Mons Veneris 1477 
The Large Lips or Labia Maj ora . 1477 
The Small Lips, Nymphae or Labia Minora 1478 
The Clitoris 1479 
The Vestibule 1481 
The Orifice of the Urethra or the Meatus 
Urinarius 1481 
The Hymen 1481 
Glands of Bartholin 1482 
The Vaginal Bulb or Bulb of the Vestibule 1483 CONTENTS 
XXV 
PAGE 
Internal Organs. 
The Vagina. 
Relations 1484 
Structure 1484 
The Womb or Uterus. 
The Fundus 1487 
The Body of the Uterus 1487 
The Neck or Cervix Uteri 1488 
Folds and Ligaments 1489 
The Cavity of the Uterus 1491 
The Cavity of the Cervix or Cervical Canal 1491 
Surgical Anatomy 1496 
The Adnexa or Appendages of Uterus. 
The Fallopian Tube. 
Structure of the Fallopian Tube . . . 1498 
PAGE 
The Epo-ophoron, Parovarium or Organ of 
Rosenmuller 1499 
The Paro-ophoron 1499 
The Ovary. 
Supports and Connections of the Ovary 1500 
Descent of the Ovary 1501 
The Ovary at Different Ages . 1501 
Structure 1501 
Surgical Anatomy of the Appendages . . 1503 
The Mammary Gland. 
Description of a Well-developed Breast . 1503 
The Nipple 1504 
Prolongation of Mammary Tissue . 1505 
Structure of Mammary Gland and Nipple . 1505 
Surgical Anatomy 1508 
The Male Breast 1509 
Surgical Anatomy 1509 
THE SURGICAL ANATOMY OF INGUINAL AND FEMORAL 
HERNIA. 
Dissection 1511 
Inguinal Hernia. 
Oblique Inguinal Hernia 1520 
Congenital Hernia 1523 
Infantile and Encysted Hernia . 1523 
Hernia into Funicular Process .... 1523 
Direct Inguinal Hernia 1523 
Femoral Hernia. 
Varieties of Femoral Hernia .... 1534 
SURGICAL ANATOMY OF THE PERINEUM. 
Dissection 1535 
Ischio-rectal Region. 
Dissection 1536 
The Perinceum Proper in the Male. 
Position of the Viscera at the Outlet of the 
Pelvis 1540 
Surgical Anatomy 1541 
The Female Perinoeum. 
The Pelvic Fascia 1544 
The Obturator Fascia 1546 
The Recto-vesical Fascia or the Visceral 
Layer of the Pelvic Fascia .... 1546 
Chronological Table of the Development of the Fcetus 1547 
Index 1549 DESCRIPTIVE AND SURGICAL 
ANATOMY. 
OSTEOLOGY-THE SKELETON 
FJ1HE entire skeleton in the adult consists of 200 distinct bones. These are: 
The spine or vertebral column (sacrum and coccyx included) .... 26 
Cranium 8 
Face 14 
Hyoid bone, sternum, and ribs 26 
Upper extremities 64 
Lower extremities 62 
200 
In this enumeration the patelhe are included as separate bones, but the smaller 
sesamoid bones and the ossicula auditus are not reckoned. The teeth belong to 
the tegumentary system. Different anatomists make different computations as 
to the number of bones in the skeleton. Some describe the skeleton as containing 
206 distinct bones, adding the ossicles of the ear to the previously stated number. 
By adding the epipteric bones, the sphenoidal turbinal bones, the sesamoid bones, 
and others, the number may be greatly augmented. 
Bones are divisible, according to their shape, into four classes: long, short, flat, 
and irregular. 
Long Bones.-The long bones are found in the limbs, where they form a 
system of levers, which sustain the weight of the trunk and confer the power 
of locomotion. A long bone consists of a shaft and two extremities. The shaft 
is a hollow cylinder, contracted and narrowed to afford greater space for the 
bellies of the muscles; the walls consist of dense, compact tissue of great thick- 
ness in the middle, but becoming thinner toward the extremities; the spongy 
tissue is scanty, and the bone is hollowed out in its interior to form the medullary 
canal. The extremities are generally somewhat expanded for greater convenience 
of mutual connection, for the purpose of articulation, and to afford a broad 
surface for muscular attachment. Here the bone is made up of spongy tissue 
with only a thin coating of compact substance. The long bones are not straight, 
but curved, the curve generally taking place in two directions, thus affording 
greater strength to the bone. The bones belonging to this class are the clavicle, 
humerus, radius, ulna, femur, tibia, fibula, metacarpal and metatarsal bones, and 
the phalanges. 
Short Bones.-Where a part of the skeleton is intended for strength and com- 
pactness, and its motion is at the same time slight and limited, it is divided into 
a number of small pieces united together by ligaments, and the separate bones 
are short and compressed, such as the bones of the carpus and tarsus. These 
bones, in their structure, are spongy throughout, excepting at their surface, where 
33 34 
THE SKELETON 
there is a thin crust of compact substance. The patellae also, together with the 
other sesamoid bones, are bv some regarded as short bones. 
Flat Bones.-Where the principal requirement is either extensive protection 
or the provision of broad surfaces for muscular attachment, we find the osseous 
structure expanded into broad, flat plates, as is seen in the bones of the skull 
and the shoulder-blades. Flat bones are composed of two thin layers of com- 
pact tissue enclosing between them a variable quantity of cancellous tissue. In 
the cranial bones these layers of compact tissue are familiarly known as the tables 
of the skull; the outer table is thick and tough; the inner table is thinner, denser, 
and more brittle, and hence is termed the vitreous table. The intervening can- 
cellous tissue is called the diploe. The flat bones are: the occipital, parietal, frontal, 
nasal, lachrymal, vomer, scapula, os innominatum, sternum, ribs, and patella. 
Irregular Bones.-The irregular or mixed bones are such as, from their pecu- 
liar form, cannot be grouped under either of the preceding heads. Their structure 
is similar to that of other bones, consisting of a layer of compact tissue externally 
and of spongy, cancellous tissue within. The irregular bones are: the vertebrae, 
sacrum, coccyx, temporal, sphenoid, ethmoid, malar, superior maxilla, inferior maxilla, 
palate, inferior turbinated, and hyoid. 
Surfaces of Bones.-If the surface of any bone is examined, certain eminences 
and depressions are seen, to which descriptive anatomists have given the following 
names. 
These eminences and depressions are of two kinds: articular and non-articular. 
Well-marked examples of articular eminences are found in the heads of the 
humerus and femur and of articular depressions in the glenoid cavity of the 
scapula and the acetabulum. Non-articular eminences are designated according 
to their form. Thus a broad, rough, uneven elevation is called a tuberosity; a 
small, rough prominence, a tubercle; a sharp, slender, pointed eminence, a spine; 
a narrow, rough elevation, running some way along the surface, a ridge, line, or 
crest. 
The non-articular depressions are also of very variable form, and are described 
as fossae, grooves, furrows, fissures, notches, sulci, etc. These non-articular emi- 
nences and depressions may receive blood-vessels, nerves, tendons, ligaments, or 
portions of organs, or may serve to increase the extent of surface for the attach- 
ment of ligaments and muscles. They are usually well marked in proportion to 
the muscular development of the subject. 
A prominent process projecting from the surface of a bone which it has never 
been separate from or movable upon is termed an apophysis (from d-b^ooK;, an 
excrescence); but if such process is developed as a separate piece from the rest of 
the bone, to which it is afterward joined, it is termed an epiphysis (from 
an accretion). The main part of the bone, or shaft, which is formed from the 
primary centre of ossification, is termed the diaphysis, and is separated, during 
growth, from the epiphysis by a layer of cartilage, at which growth in length of 
the bone takes place. Some bones are hollow and contain sinuses, which are 
spaces for air. Canals or foramina are channels or openings in bone through 
which nerves or vessels pass. 
Structure of Bone.-Bone is a highly specialized form of connective tissue. 
In reality, it is white fibrous tissue, calcified and structurally modified until it 
becomes osseous tissue. Bone is not simply a crude mass resulting from the 
calcification of cartilage or fibrous tissue; it is a distinct tissue, of a definite struc- 
ture, the constituent parts of which are arranged symmetrically. Its structure 
varies somewhat in different vertebrates.1 
1 Arquitectura del Aparato de Sustentacion en los Vertebrados. Por el Dr. Saturnino Garcia Hurtado. Our 
description applies to human bone. STRUCTURE OF BONE 
35 
There are two varieties of bone: dense or compact bone (substantia compacta), 
and cancellous, loose, or spongy bone (substantia spongiosa). 
Compact Bone is dense, like ivory, and is always placed upon the exterior of 
bones. Even this apparently compact tissue is porous; it differs from cancellous 
bone in the greater density of its tissue and in the arrangement of its osseous 
plates into Haversian systems. Compact bone is surrounded by periosteum. 
OSTEOGEN ETIC, 
CELLS * 
aggT"'" 
Mm 
LAMELl<f 
AREA 
OCCUPIED BY 
A HAVERSIAN 
SYSTEM 
^naucul, 
contents 
Of canal 
lacuna 
LAMELLA 
LACUNAE H 
CANALICULlJ 
HAVERSIAN - 
CANAL ' 
-COMPLETE 
'HAVERSIAN 
SYSTEM 
Fig. 1.-Diagram of the structure of osseous tissue. A small part of a transverse section of the shaft of a long 
bone is shown. At the uppermost part is the periosteum covering the outside of the bone ; at the lowermost part 
is the endosteum lining the marrow-cavity. Between these is the compact tissue, consisting largely of a series of 
Haversian systems, each being circular in outline and perforated by a central canal. In the first one is shown 
only the area occupied by a system; in the second is seen the concentric arrangement of the lamellae; and in the 
others, respectively, canaliculi; lacunae; lacunae and canaliculi; the contents of the canal, artery, vein, lymphatic 
and areolar tissue; lamellae, lacunae, and canaliculi; and, finally, all of the structures composing a complete sys- 
tem. Between the systems are circumferential and intermediate lamellae, only a few of which are represented as 
lodging lacunae, though it is to be understood that the lacunae are in all parts. The periosteum is seen to be 
made up of a fibrous layer and a vascular layer, and to have upon its attached surface a stratum of cells. From 
the fibrous layer project inward the rivet-like fibres of Sharpey. (F. H. Gerrish.) 
The outer portion of the wall of a long bone, the cortex of the head of a bone, 
and the outer and inner layers of a flat bone are composed of compact osseous 
tissue, which is the hardest substance in the body with the exception of dentine 
and enamel; it is tough and elastic, and much force is required to break it. 
Cancellous Bone is found in the interior of bones. The name, which means 
lattice-work, indicates the structure, which consists of slender fibres and lamellae 
joined to form a reticulum, the small meshes of which are marrow-spaces. The 36 
THE SKELETON 
spicules of cancellous bone contain lacunae and canaliculi, but no Haversian 
systems. In some regions the inner portion of the wall of a long bone, about the 
marrow-cavity, is composed of cancellous bone. Toward each extremity of the 
shaft the amount of cancellous tissue increases, the marrow-cavity diminishes in 
size, and the cancellous tissue is arranged in lines that approach each other toward 
the extremity, like the sides of an arch, and form a support for the epiphysis 
(Fig. 131). In the epiphysis the bone-plates are, as a rule, at right angles to 
the plane of the articular surface (the lines of greatest pressure); and they are 
bound together or strengthened by other bone-fibres, which are usually in corre- 
spondence with the planes of the articulation (the lines of greatest tension) (Fig. 
163). The nearer the bone-spicules are to the medullary cavity the stronger they 
are (Hurtado). 
In the flat and the irregular bones, the cancellous tissue is between the layers 
of compact bone, and is called the diploe. 
A Short Bone is composed chiefly of cancellous tissue, which is encased in a 
thin coat of compact substance (substantia corticalis). 
A Long Bone consists of a shaft, or diaphysis, and two extremities, or epiphyses. 
The shaft is an osseous tube, the outer layer of which is compact, and the inner 
layer of which is cancellous. It surrounds the medullary cavity (cavum medullare), 
which, in the recent condition, contains the medulla, or marrow (medulla ossium), 
which substance enters into the nearest Haversian canals. This cavity is widest 
at the centre of the shaft, and narrows toward the ends, where it is encroached 
upon by the cancellous layer which lies within the compact layer. 
There are two varieties of marrow: Yellow marrow (medulla ossium flava) is 
found in the medullary cavities of the shafts of the long bones. It is composed 
of a network of fibrous tissue carrying many blood-vessels, fat-cells, and a few 
large nucleated masses of protoplasm-the true marrow-cells, or myelocytes. 
The yellow color of the marrow is due to fat. Yellow marrow is derived from 
red marrow by an increase in fat and diminution in marrow elements; it plays 
no part in blood-formation. At the periphery of the marrow cavity the fibrous 
tissue of the network forms a firm, fibrous membrane lining the cavity. This 
represents an inner periosteum, and is called the endosteum. 
Red marrow (medulla ossium rubra) is found in the diploe of the cranial bones, in 
the cancellous tissue of the vertebra, ribs, and sternum, and in the articular ends 
of the long bones. Red marrow contains much less fat and is less solid than yellow 
marrow. It consists of a delicate network of connective tissue, supporting a 
dense capillary plexus; some fat; and numerous cellular elements. The delicate 
fibrous membrane surrounding red marrow is called the endosteum. The 
cellular elements of red marrow (Fig. 2) comprise, first, marrow-cells, or myelocytes, 
which are protoplasmic masses, capable of amoeboid movements, and containing 
large nuclei. They are not found in normal blood, but are abundant in leuksemia; 
second, small, nucleated, reddish cells called erythroblasts, resembling the nucleated 
red cells of the blood of the embryo, and eventually by the loss of their nuclei 
becoming red blood-corpuscles; third, non-nucleated red blood-corpuscles; fourth, 
giant-cells containing one or more nuclei. They are varieties of leukocytes. The 
leukocyte group also contains the osteoclasts, eosinophiles, and mast-cells. 
Gelatinous or mucoid marrow is formed by the absorption of the fat and the 
cellular elements of yellow marrow, and by the serous infiltration of the inter- 
cellular substance. It is produced by starvation, old age, and certain pathological 
conditions. 
Each extremity of a long bone is separated from the shaft by a layer of car- 
tilage known as the cambium layer, the epiphysial cartilage, or the epiphysial 
disk (Fig. 8). Growth from the cartilages causes an increase in the length of 
the bone. The cartilages ossify during development, and effect a bony union STRUCTURE OF BONE 
37 
between the shaft and the head of the bone. Certain bony processes are 
separated from the bone by cartilage, which later ossifies. 
A Flat Bone is composed of two layers of compact bone with a layer of can- 
cellous bone (the diploe) interposed. There is no general marrow-cavity; but 
the spaces between the bone-spicules intercomm.unicate and contain marrow. 
Fig. 2.-Cells of red marrow of the guinea-pig. a-d. Myelo-plaques. e-i. Marrow-cells proper, j-t. Erythro- 
blasts-some in process of division. (Schafer.) 
The Periosteum is a fibrous membrane adhering to the surface of the bone in 
nearly every part except at the cartilage-covered extremities. When strong ten- 
dons or ligaments are attached to the bone, the periosteum is incorporated with 
them. By means of the periosteum many vessels reach and enter the hard bone 
through Volkmann's canals. This is shown by stripping the periosteum from the 
surface of living bone, when small bleeding points are seen, each of which 
marks the entrance of a vessel from the periosteum. It thus becomes obvious 
that the loosening of the periosteum, by depriving a portion of the bone of its 
nourishment, may produce necrosis. The membrane is firmly attached to the 
bone by trabeculae of fibrous tissue, which pene- 
trate the bone at right angles to its surface, and 
carry blood-vessels. These trabeculae are called 
the fibres of Sharpey (Fig. 3). They do not di- 
rectly enter the Haversian systems, but only the 
circumferential and intermediate lamellae-parts 
that are formed by periosteal action. Prolonga- 
tions from some of these vessels reach the Haver- 
sian canals, and even the bone-marrow. In the 
extremities of a long bone, vessels from the peri- 
osteum penetrate the layer of compact bone and 
reach the cancellous tissue. In the newborn and 
in the young the periosteum is composed of three 
layers: an outer or fibrous layer, containing some 
blood-vessels, and composed of bundles of white 
fibrous tissue; a middle or fibro-elastic layer, con- 
taining some blood-vessels, fibrous tissue, and 
much elastic tissue; and an inner or osteogenetic layer, which is very vascular and 
contains numerous cells, which are converted into osteoblasts. These are the 
cells that form osseous tissue. 
Fig. 3.-Fibres of Sharpey from the 
parietal bone (adult man) isolated by 
dissociation. (After Kiilliker.) 38 
THE SKELETON 
Transverse Section of Compact Bone (Figs. 1, 4, and 6).-As previously stated, 
dense bone differs from cancellous bone in the fact that the bone-plutes of the 
former are arranged in Haversian systems, so named from the anatomist 
Havers. A Haversian system consists of a central canal, running in a more or 
less longitudinal or slightly curved or spiral direction and called the Haversian 
canal; from five to ten bone-plates, or lamellae, arranged concentrically around the 
canal; gaps, called lacunae, between the lamelke, which spaces contain bone-cor- 
puscles; minute channels, or canaliculi, radiating from the lacunae and passing 
through the lamellae-some reaching other lacunae, some reaching the Haver- 
sian canal, and others passing to adjacent Haversian systems. The canaliculi 
contain processes from the bone-corpuscle. From a study of transverse sections 
it would be thought that the lamellae always run longitudinally in straight lines 
or in curves determined by pressure and tension; but Prof. Dixon proved that 
in the human femur many of the bone-plates are arranged spirally, and thus 
increased strength is obtained. The same is probably true of other bones. 
Fig. 4.-Transverse section of compact tissue of bone. Magnified about 150 diameters. (Sharpey.) 
There are four varieties of lamellae: (1) the periosteal, peripheral, superficial, 
or external; (2) the Haversian, or concentric; (3) the interstitial, ground, or inter- 
mediate; and (4) the perimedullary, or internal. The periosteal lamellae are some- 
times called primary, as they are the first to appear, and are formed by the direct 
transformation of the inner layer of the periosteum into bone. In the shaft of 
a long bone there are several layers of periosteal lamellae, but no one layer is 
extensive enough to surround the bone completely. 
In the outer surface of the layer of periosteal lamellae depressions exist that 
are known as Howship's foveolae, or lacunae. These depressions are made by 
large cells, called osteoclasts, which destroy bone. There are no Haversian 
canals in this outer layer, but there are some large channels that convey blood- 
vessels into the bone, and are known as Volkmann's canals. Many small arteries 
from the periosteum enter the periphery of the shaft, and also of the epiphyses. 
A large trunk enters the shaft by the nutrient foramen (joramen nutricius), pass 
along the nutrient canal (canalis nutricius), and reaches the medullary canal. 
This vessel is called the nutrient artery. 
The Haversian or concentric lamellae are circular layers arranged around a 
central space, or canal, known as the Haversian canal. There is no fixed num- 
ber of these layers, there being usually from five to ten. The layers of each system 
are parallel to one another, but the layers of different systems cross at various BLOOD-VESSELS OE BONE 
angles. Between these layers are small, irregular spaces, called lacunae; and 
extending radially out from the lacunae and piercing the various lamellae are 
delicate canals, known as canaliculi, which connect the lacunae. The lacuna 
nearest to the Haversian canal communicates with it by means of canaliculi; 
and canaliculi also communicate with other Haversian systems. The Haversian 
canal contains blood-vessels-an artery or a vein, or both an artery and a vein- 
and a nerve. The vessel in the canal is covered with endothelial cells, and the 
canal itself is lined with them. The space thus formed is a lymph-space, and 
into these lymph-spaces the canaliculi empty. Beneath the periosteum and at 
the periphery of the medullary cavity there are lymph-spaces that are in direct 
communication with the canaliculi of the Haversian systems. In each lacuna is 
a bone-cell-a corpuscle that almost fills the space, and sends arms, or processes, 
out into the canaliculi (Fig. 5). This bone-cell is an osteoblast. 
The interstitial or intermediate lamellae occupy the spaces between the 
Haversian systems. They represent the remains of peripheral lamellae. They 
are usually short and very 
irregular, but possess lacunae 
and canaliculi, which are ar- 
ranged as in the Haversian 
systems. The perimedullary 
lamellae are irregular and few 
in number. 
39 
Fig. 5.-Nucleated bone-cells and their 
processes, contained in the bone-lacunae and 
their canaliculi, respectively. From a section 
through the vertebra of an adult mouse. 
(Klein and Noble Smith.) 
Fig. 6.-Combined transverse and longitudinal section of 
compact bone. CH. Longitudinal Haversian canal and 
anastomosing canals, o. Communicating with medullary 
cavity. Si. Intermediate systems. Spe. Circumferential 
lamellae. Spi. Perimedullary lamellae. os. Osteoblasts. 
(Poirier and Charpy.) 
The osteoblasts are irregular, flattened, stellate masses of protoplasm, pos- 
sessing a number of processes. The protoplasm is granular, and each cell con- 
tains a large and distinct nucleus. Osteoblasts are met with in the deeper layer 
of the periosteum, in the endosteum, and in the lacunae. 
Longitudinal Section of Compact Bone (Figs. 6 and 7).-We do not see con- 
centric rings, as in a transverse section, but rows of lacunae parallel to the course 
of the Haversian canals-and these canals appear like half-tubes instead of 
circular spaces. The tubes are seen to branch and communicate, so that each 
separate Haversian canal runs only a short distance. In other respects the 
structure closely resembles that of a transverse section. 
Lamellae of Cancellous Bone.-There are no Haversian canals, and canaliculi 
open into the medullary spaces, which act as do the Haversian canals in com- 
pact bone. 
Blood-vessels of Bone.-Small arteries derived from the periosteum enter 
the minute orifices of the compact bone (Volkmann's canals) and reach the THE SKELETON 
40 
Haversian canals of the bony substance. Prolongations from these vessels 
reach the marrow and communicate with branches from the nutrient artery. 
The cancellous tissue is supplied by fewer but larger vessels, which are derived 
from the periosteum, and which often penetrate the cortex of compact bone 
and ramify in the cavities of the spongy tissue. 
Fig. 7.-From a ground longitudinal section through the diaphysis of the human ulna. All canals are filled 
with pigment, which is here black. Haversian canals are cut longitudinally. X 90. (Szymonowicz.) 
The medullary canal of a long bone is supplied by a large artery (sometimes 
more than one) called the nutrient artery. It enters the bone by the nutrient 
foramen, which is usually near the centre of the shaft, runs in an oblique canal 
through the compact structure, giving off branches to this structure, and enters 
the medullary cavity, and sends branches upward and downward. These branches 
communicate with branches from the periosteal vessels and subdivide into capil- 
laries, which pass into comparatively large vessels. The walls of the vessels are 
very thin, and in some places deficient; the venous blood enters the spaces of 
the red marrow, and the current becomes extremely slow. Small veins collect 
the venous blood and emerge from the bone. 
In the humerus the nutrient canal is directed toward the elbow-joint; in the 
radius and the ulna the nutrient canals are directed toward the elbow-joint; in 
the femur, the canal is directed toward the hip-joint; and in the tibia and the 
fibula, the canals are directed toward the ankle-joint. As Professor Cunningham 
states it: "In the upper limb the vessels flow toward the elbow; while in the CHEMICAL COMPOSITION OF BONE 
41 
lower limb they pass from the knee." The red marrow of the extremities and 
the medulla of the entire shaft, and the bone of the shaft, except the circum- 
ferential lamellae, are supplied by the nutrient artery. The circumferential 
lamellae, wholly, and the cancellous tissue of the extremities, in part, and the 
medulla of the shaft to a very small extent are supplied by vessels from the 
periosteum. The extremities of a bone also receive articular arteries. In most 
of the flat bones, and in some of the short bones, one or more large apertures exist 
for the passage of blood-vessels to the central parts of the bone. 
Veins emerge from the long bones in three places: 1. One or two large veins 
accompany the nutrient artery. 2. Numerous veins emerge at the articular 
extremities. 3. Many small veins arise in and emerge from compact substance. 
The latter two classes do not accompany arteries. The veins in the marrow 
and in the bone are devoid of valves; but immediately after emerging from the 
bone they have numerous valves. 
In the flat cranial bones the veins are numerous and large; as seen in diploic 
canals, the walls of which are composed of osseous tissue, perforated, here and 
there, for branches from adjacent cancelli. In all cancellous tissue the venous 
channels are similarly arranged, and the veins have very thin coats and are 
without valves. When the bone is divided, the vessels remain open; they do 
not retract into their bony canals, and readily absorb any septic matter that 
may be present. 
The lymphatics are chiefly periosteal; but some enter the bone, along with the 
vessels. Cruikshank has traced them into the substance of the bone and Klein 
has described them as running in the Haversian canals. The perivascular spaces 
of the Haversian canals are lymph-spaces. 
Nerves are partly medullated and partly non-medullated, are distributed freely 
to the periosteum, and some of the fibres terminate in this structure as Pacinian 
corpuscles. Nerves accompany the nutrient arteries into the interior of the 
bone, and also reach the marrow from the periosteum by way of Volkmann's 
canals and the Haversian canals. They certainly supply the arterial coats. 
It is not, as yet, determined whether nerves do or do not terminate in bone-tissue. 
Stroh maintains that occasionally they terminate in bone-corpuscles. According 
to Kolliker nerves are most numerous in the articular extremities of the long 
bones, in the vertebrae, and the large flat bones. 
Chemical Composition of Bone.-Bone consists of an animal and an earthy 
part intimately combined. 
The animal part may be obtained by immersing the bone for a considerable 
time in dilute mineral acid, after which process the bone comes out exactly the 
same shape as before, but perfectly flexible, so that a long bone (one of the ribs, 
for example) can easily be tied into a knot. If now a transverse section is made, 
the same general arrangement of the Haversian canals, lamellae, lacunae, and 
canaliculi is seen, though not so plainly, as in the ordinary section. 
The earthy part may be obtained separate by calcination, by which the animal 
matter is completely burned out. The bone will still retain its original form, but 
it will be white and brittle, will have lost about one-third of its original weight, 
and will crumble with the slightest force. The earthy matter confers on bone 
its hardness and rigidity, and the animal matter its tenacity. 
The mineral matter consists of phosphate, carbonate, and fluoride of calcium, 
chloride of sodium, and phosphate of magnesium. 
The animal basis is largely composed of ossein, or fat collagen. When boiled 
with water, especially under pressure, fat collagen is almost entirely resolved 
into gelatin. 
The organic matter of bone forms about one-third; the inorganic matter, 
two-thirds. The exact composition, according to Professor Cunningham, is, of 42 
THE SKELETON 
organic matter, 31.04 parts; of inorganic matter, 68.97 parts. Of the earthy 
matter, five-sixths is calcium phosphate. Even after the removal of all the 
marrow a small percentage of fat is still found in bone. 
Some of the diseases to which bones are liable mainly depend on the dispro- 
portion between the two constituents of bone. Thus in the disease called rickets, 
so common in the children of the poor, the bones become bent and curved, either 
from the superincumbent weight of the body or under the action of certain mus- 
cles. This depends upon some defect of nutrition by which bone becomes deprived 
of its normal proportion of earthy matter, while the animal matter is of unhealthy 
quality. In the vertebrae of a rickety subject Bostock found in 100 parts 79.75 
animal and 20.25 earthy matter. Osteomalacia is a disease of adults charac- 
terized by the decalcification of existing bone and by the failure in calcification 
of new osteoid material. In this disease the bone shows a diminution in 
inorganic and an increase in organic material. Senile atrophy renders bones 
porous and brittle, and portions of bone may actually be absorbed, as is seen in 
the disappearance of the alveolne in old age. In senile atrophy of the calvaria 
the outer table becomes very thin, porous, and brittle, and the inner table often 
becomes rough and thicker from the formation of new bone. In senile atrophy 
of a long bone there is absorption of bone from the surface by osteoclasts in 
Howship's lacunae, and absorption of the inner surface. The bone becomes 
porous and the medulla becomes more fatty. This change is not, as was so 
long taught, a decrease in organic matter 
and an increase in mineral matter, but is an 
actual alteration in the structure of the bone. 
Ossification and Growth of Bone.-For 
the early development of the skeleton the 
reader is referred to text-books on embry- 
ology. Embryonic connective-tissue cells of 
the mesoblast develop membrane. Membrane 
may become bone directly or cartilage may be 
deposited, which cartilage by the process of 
ossification is formed into bone. The tissue 
which is eventually to become bone contains 
cellular elements which evolve into osteoblasts, 
or bone-forming cells. Osteoblasts exist in the 
connective tissues which become bone by in- 
tramembranous ossification, and in the deeper 
layers of the tissue called perichondrium which 
invests cartilage and which becomes the osteo- 
genetic layer of the periosteum. In view of 
the fact that in the foetal skeleton some bones 
are preceded by membrane (parietal bones, frontal bone, upper part of tabular 
surface of occipital bone, most of bones of the face), and others are preceded by 
rods of cartilage (the long bones), two kinds of ossification are described-viz., 
the intramembranous and the intracartilaginous. Professor Cunningham says all 
true bone may be correctly regarded as of membranous origin, though its appear- 
ance is preceded in some instances by the deposition of cartilage; in this case 
calcification of the cartilage is an essential stage in the process of bone forma- 
tion, but the ultimate conversion into true bone, with characteristic Haversian 
systems, leads to the absorption and disappearance of this primitive calcified 
cartilage. Intramembranous ossification forms membrane bones, that is, forms 
bone directly from fibrous tissue, there being no intermediate cartilaginous 
stage. 
Intracartilaginous ossification consists in the ossification of cartilage. 
Fig. 8.-Schematic diagram, showing epi- 
physis and diaphysis and line of ossification. 
Ep. Epiphysis of endochondral bone. zpt. 
Zone of proliferation, zc. Zone of calcifica- 
tion. ca. Cartilage. (Poirier and Charpy.) OSSIFICA TION A ND GROWTH OF BONE 
43 
Intramembranous Ossification.-In the case of bones which are developed in 
membrane no cartilaginous mould precedes the appearance of the bone-tissue. 
The membrane, which occupies the place of the future bone, is of the nature of 
connective tissue, and ultimately forms the periosteum. At this stage it is seen 
to be composed of fibres and granular cells in a matrix. The outer portion is 
more fibrous, while internally the cells or osteoblasts predominate; the whole 
tissue is richly supplied with blood-vessels. At the outset of the process of bone- 
formation a little network of bony spiculre is first noticed radiating from the point 
or centre of ossification. When these rays of growing bone are examined with a 
microscope, they are found to consist at their growing point of a network of fine, 
clear fibres and granular corpuscles, with an intervening ground substance 
(Fig. 9). The fibres are termed osteogenetic fibres, and are made up of fine fibrils 
Union of. 
adjacent 
spicules. 
Osteogenetic 
fibres. 
Calcific deposit 
between the 
fibres. 
Osteoblasts.* 
Bony 
spicules. 
Fig. 9.-Part of the growing edge of the developing parietal bone of a foetal cat. (After J. Lawrence.) 
differing little from those of white fibrous tissue. Like them, they are probably 
deposited in the matrix through the influence of the cells-in this case the osteo- 
blasts. The osteogenetic fibres soon assume a dark and granular appearance from 
the deposition of calcareous granules in the fibres and in the intervening matrix, 
and as they calcify they are found to enclose some of the granular corpuscles or 
osteoblasts. By the fusion of the calcareous granules the bony tissue again assumes 
a more transparent appearance, but the fibres are no longer so distinctly seen. 
The involved osteoblasts form the corpuscles of the future bone, the spaces in 
which they are enclosed constituting the lacunae. As the osteogenetic fibres grow 
out to the periphery they continue to calcify, and give rise to fresh bone-spicules. 
Thus a network of bone is formed, the meshes of which contain the blood-vessels 
and a delicate connective tissue crowded with osteoblasts. The bony trabeculae 
thicken by the addition of fresh layers of bone formed by the osteoblasts on their 
surface, and the meshes are correspondingly encroached upon. Subsequently 
successive layers of bony tissue are deposited under the periosteum and around 
the larger vascular channels, which become the Haversian canals, so that the bone 
increases much in thickness. 
Intracartilaginous Ossification.-Just before ossification begins the bone is 
entirely cartilaginous, and in the long bone, which may be taken as an example, the 
process commences in the centre and proceeds toward the extremities, which for 
some time remain cartilaginous. Subsequently a similar process commences in one 44 
THE SKELETON 
or more places in those extremities and gradually extends through them. The 
extremities do not, however, become joined to the shaft by bony tissue until growth 
has ceased, but are attached to it by a layer of cartilaginous tissue termed the 
epiphysial cartilage (Fig. 8). 
The first step in the ossification of the cartilage is that the cartilage-cells, at 
the point where ossification is commencing and which is termed a centre of ossifica- 
tion, enlarge and arrange themselves in rows (Fig. 10). The matrix in which they 
are embedded increases in quantity, so that the cells become further separated 
from each other. A deposit of calcareous material now takes place in this matrix. 
Fig. 11.-Part of a longitudinal section of 
the developing femur of a rabbit, a. Flat- 
tened cartilage-cells, b. Enlarged cartilage- 
cells. c, d. Newly formed bone. e. Osteo- 
blasts. f. Giant-cells or osteoclasts, g, h. 
Shrunken cartilage-cells. (From Atlas of His- 
tology, Klein and Noble Smith.) 
Fig. 10.-Section of foetal bone of cat. ir. Irruption 
of the subperiosteal tissue, p. Fibrous layer of the peri- 
osteum. o. Layer of osteoblasts. im. Subperiosteal 
bony deposit. (From Quain's Anatomy, E. A. Schafer.) 
between the rows of cells, so that they become separated from each other by longi- 
tudinal columns of calcified matrix, presenting a granular and opaque appearance. 
Here and there the matrix between two cells of the same row also becomes calci- 
fied, and transverse bars of calcified substance stretch across from one calcareous 
column to another. Thus there are longitudinal groups of the cartilage-cells 
enclosed in oblong cavities, the walls of which are formed of calcified matrix, 
which cuts off all nutrition from the cells, and they, in consequence, waste, leav- 
ing spaces called the primary areolae (Sharpey). 
At the same time that this process is going on in the centre of the solid bar of 
cartilage of which the foetal bone consists, certain changes are taking place on OSSIFICATION AND GROWTH OF BONE 
45 
its surface. This is covered by a very vascular membrane, the perichondrium, 
entirely similar to the embryonic connective tissue already described as constituting 
the basis of membrane-bone, on the inner surface of which, that is to say, on the 
surface in contact with the cartilage, are gathered the formative cells, the osteo- 
blasts. By the agency of these cells a thin layer of bony tissue is being formed 
between the perichondrium and the cartilage, by the intramembranous mode of 
ossification just described. There are, then, in this first stage of ossification, two 
processes going on simultaneously: in the centre of the cartilage the formation 
of a number of oblong spaces, formed of calcified matrix and containing the 
withered cartilage-cells, and on the surface of the cartilage the formation of a 
layer of true membrane-bone. The second stage consists in the prolongation 
into the cartilage of processes of the 
deeper or osteogenetic layer of the 
perichondrium, which has now be- 
come periosteum (Fig. 10, ir). The 
processes consist of blood-vessels and 
cells-osteoblasts, or bone-formers, and 
osteoclasts, or bone-destroyers. The 
latter are similar to the giant-cells 
(myelo-plaques) found in marrow, 
and they excavate passages through 
Fig. 13.-Vertical section from the edge of the 
ossifying portion of the diaphysis of a metatar- 
sal bone from a foetal calf. a. Ground-mass of 
the cartilage, b. Of the bone. c. Newly formed 
bone-cells in profile, more or less embedded in in- 
tercellular substance, d. Medullary canal in pro- 
cess of formation, with vessels and medullary 
cells. e,f. Bone-cells on their broad aspect, g. 
Cartilage-capsules arranged in rows, and partly 
with shrunken cell-bodies. (After Muller.) 
Fig. 12.-Transverse section from the femur of a 
human embryo about eleven weeks old. a. A med- 
ullary sinus cut transversely, and b, another, longi- 
tudinally. C. Osteoblasts, d. Newly formed osseous 
substance of a lighter color, e. That of greater age. 
f. Lacuna- with their cells, g. A cell still united to 
an osteoblast. 
the new-formed bony layer by absorption, and pass through it into the cal- 
cified matrix (Fig. 10). Wherever these processes come in contact with the 
calcified walls of the primary areolte they absorb it, and thus cause a fusion 
of the original cavities and the formation of larger spaces, which are termed 
the secondary areolae (Sharpey), or medullary spaces (Miiller). In these second- 
ary spaces the original cartilage-cells, having disappeared, become filled 
with embryonic marrow, consisting of osteoblasts and vessels, and derived in 46 
THE SKELETON 
the manner described above, from the osteogenetic layer of the periosteum 
(Fig. 11). 
Thus far there has been traced the formation of enlarged spaces (secondary 
areolae), the perforated walls of which are still formed by calcified cartilage- 
matrix, containing an embryonic marrow, derived from the processes sent in 
from the osteogenetic layer of the periosteum, and consisting of blood-vessels 
and round-cells, osteoblasts (Fig. 11). The walls of these secondary areolae are 
at this time of only inconsiderable thickness, but they become thickened by 
the deposition of layers of new bone on their interior. This process takes place 
in the following manner: Some of the osteoblasts of the embryonic marrow, 
after undergoing rapid division, arrange themselves as an epithelioid layer on 
the surface of the wall of the space (Fig. 12). This layer of osteoblasts form a 
bony stratum, and thus the wall of the space becomes gradually covered with a 
layer of true osseous substance. On this a second layer of osteoblasts arrange 
themselves, and in their turn form an osseous layer. By the repetition of this 
process the original cavity becomes very much reduced in size, and at last only 
remains as a small circular hole in the centre, containing the remains of the 
embryonic marrow-that is, a blood-vessel and a few osteoblasts. This small 
cavity constitutes the Haversian canal of the perfectly ossified bone. The successive 
layers of osseous matter which have been laid down and which encircle this central 
canal constitute the lamellae of 
which, as we have seen, each 
Haversian system is made up. 
As the successive layers of os- 
teoblasts form osseous tissue, 
certain of the osteoblastic cells 
remain included between the 
various bony layers. These 
persist as the corpuscles of the 
future bone, the spaces enclos- 
ing them forming the lacunae 
(Figs. 12 and 14). The canal- 
iculi, at first extremely short, are 
supposed to be extended by ab- 
sorption, so as to meet those of 
neighboring lacunae. 
Such are the changes which 
may be observed at one partic- 
ular point, the centre of ossifi- 
cation. While they have been going on here a similar process has been set up 
in the surrounding parts and has been gradually proceeding toward the end of 
the shaft, so that in the ossifying bone all the changes described above may be 
seen in different parts, from the true bone in the centre of the shaft to the hyaline 
cartilage at the extremities. The bone thus formed differs from the bone of the 
adult in being more spongy and less regularly lamellated. 
Thus far, then, we have followed the steps of a process by which a solid bony 
mass is produced, having vessels running into it from the periosteum, Haversian 
canals in which those vessels run, medullary spaces filled with foetal marrow, 
lacunae with their contained bone-cells, and canaliculi growing out of these 
lacunae. 
This process of ossification, however, is not the origin of the whole of the 
skeleton, for even in those bones in which the ossification proceeds in a great 
measure from a single centre, situated in the cartilaginous shaft of a long bone, a 
considerable part of the original bone is formed by intramembranous ossification 
Fig. 14.-Osteoblasts from the parietal bone of a human embryo 
thirteen weeks old. a. Bony septa with the cells of the lacun®. 
b. Layers of osteoblasts, c. The latter in transition to bone- 
corpuscles. (After Gegenbauer.) OSSIFICATION AND GROWTH OF BONE 
47 
beneath the perichondrium or periosteum; so that the girth of the bone is increased 
by bony deposit from the deeper layer of this membrane. The shaft of the bone 
is at first solid, but a tube is hollowed out in it by absorption around the vessels 
passing into it, which becomes the medullary canal. This absorption is supposed 
to be brought about by large "giant-cells," the so-called osteoclasts of Kblliker 
(Fig. 11). They vary in shape and size, and are known by containing a large 
number of clear nuclei, sometimes as many as twenty. The occurrence of 
similar cells in some tumors of bones has led to such tumors being denominated 
" myeloid." 
As more and more bone is removed by this process of absorption from the 
interior of the bone to form the medullary canal, so more and more bone is 
deposited on the exterior from the periosteum, until at length the bone has attained 
the shape and size which it is destined to retain during adult life. As the ossifi- 
cation of the cartilaginous shaft extends toward the articular ends it carries with 
it, as it were, a layer of cartilage, or the cartilage grows as it ossifies, and thus the 
bone is increased in length. During this period of growth the articular end, or 
epiphysis, remains for some time entirely cartilaginous; then a bony centre appears 
in it, and it commences the same process of intracartilaginous ossification; but 
this process never extends to any great distance. The epiphyses remain separated 
from the shaft by a narrow cartilaginous layer for a definite time (Fig. 8). 
This layer ultimately ossifies, the distinction between shaft and epiphysis is. 
obliterated, and the bone assumes its completed form and shape. The same 
remarks also apply to the processes of bone which are separately ossified, such as 
the trochanters of the femur. The bones, having been formed, continue to 
grow until the body has acquired its full stature. They increase in length by 
ossification continuing to extend in the epiphysial cartilage, which goes on grow- 
ing in advance of the ossifying process. They increase in circumference by 
deposition of new bone, from the deeper layer of the periosteum, on their external 
surface, and at the same time an absorption takes place within, by which the 
medullary cavity is increased. 
The medullary spaces which characterize the cancellous tissue are produced by 
the absorption of the original foetal bone in the same way as the original medul- 
lary canal is formed. The distinction between the cancellous and compact tissue 
appears to depend essentially upon the extent to which this process of absorption 
has been carried; and we may perhaps remind the reader that in morbid states of 
the bone inflammatory absorption produces exactly the same change, and con- 
verts portions of bone naturally compact into cancellous tissue. 
The number of ossific centres is different in different bones. In most of the 
short bones ossification commences by a single point in the centre, and proceeds 
toward the circumference. In the long bones there is a central point of ossifica- 
tion for the shaft or diaphysis; and one or more for each extremity, the epiphysis. 
That for the shaft is the first to appear. The union of the epiphyses with the 
shaft takes place in the reverse order to that in which their ossification began, with 
the exception of the fibula, and appears to be regulated by direction of the nutrient 
artery of the bone. Thus the nutrient arteries of the bones of the arm and fore- 
arm are directed toward the elbow, and the epiphyses of the bones forming this 
joint become united to the shaft before those at the shoulder and wrist. In the 
lower limb, on the other hand, the nutrient arteries pass in a direction from the 
knee; that is, upward in the femur, downward in the tibia and fibula; and in 
them it is observed that the upper epiphysis of the femur and the lower epiphysis 
of the tibia and fibula become first united to the shaft. 
Where there is only one epiphysis, the medullary artery is directed toward 
that end of the bone where there is no additional centre, as toward the acromial 
end of the clavicle, toward the distal end of the metacarpal bone of the thumb THE SKELETON 
48 
and great toe, and toward the proximal end of the other metacarpal and meta- 
tarsal bones. 
Besides these epiphyses for the articular ends, there are others for projecting 
parts or processes, which are formed separately from the bulk of the bone. For 
an account of these the reader is referred to the description of the individual 
bones in the sequel. 
A knowledge of the exact periods when the epiphyses become joined to the 
shaft is often of great importance in medico-legal inquiries. It also aids the sur- 
geon in the diagnosis of many of the injuries to which the joints are liable; for it 
not infrequently happens that on the application of severe force to a joint the 
epiphysis becomes separated from the shaft, and such an injury may be 
mistaken for a fracture or dislocation. 
THE VERTEBRAL OR SPINAL COLUMN (THE SPINE) 
(COLUMNA VERTEBRALIS). 
The spine is a flexuous and flexible column formed of a series of bones called 
vertebrae (from vertere, to turn). 
The vertebrae are thirty-three in number, and have received the names cervical, 
dorsal or thoracic, lumbar, sacral, and coccygeal, according to the position which 
they occupy; seven being found in the cervical region, twelve in the dorsal, five 
in the lumbar, five in the sacral, and four in the coccygeal. 
This number is sometimes increased by an additional vertebra in one region, or 
the number may be diminished in one region, the deficiency being supplied by 
an additional vertebra in another. These observations do not apply to the cervical 
portion of the spine, the number of bones forming which is seldom increased or 
diminished. 
The vertebrae in the upper three regions of the spine remain separate through- 
out life, and are known as true or movable vertebrae; but those found in the 
sacral and coccygeal regions are in the adult firmly united, so as to form two 
bones-five entering into the formation of the upper bone or sacrum, and four into 
the terminal bone of the spine or coccyx. The fused vertebrae are known as 
false or immovable vertebrae. 
GENERAL CHARACTERS OF A VERTEBRA. 
Each vertebra consists of two essential parts-an anterior solid segment, the 
body, or centrum, and a posterior segment, the arch (arcus vertebrae), or the neural 
arch. The neural arch is formed of two pedicles and two laminae, supporting 
seven processes-viz., four articular, two transverse, and one spinous. 
The bodies of the vertebrae are piled one upon the other, forming a strong 
pillar for the support of the cranium and trunk; the arches forming a hollow 
cylinder behind the bodies for the protection of the spinal cord (spinal canal or 
neural canal). The different vertebrae are connected together by means of the 
articular processes and the intervertebral fibrocartilages; while the transverse 
and spinous processes serve as levers for the attachment of muscles which 
move the different parts of the spine. Lastly, between each pair of vertebrae 
apertures exist through which the spinal nerves pass from the cord. Each of 
these constituent parts must now be separately examined. 
Body, or Centrum (corpus vertebrae).-The body is the largest part of a vertebra. 
Above and below it is flattened; its upper and lower surfaces are rough for the 
attachment of the intervertebral fibro-cartilages, and each presents a rim around 
its circumference. In front it is convex from side to side, concave from above 
downward. Behind it is flat from above downward and slightly concave from THE CER VIC AL VERTEBRAE 
49 
side to side. Its anterior surface is perforated by a few small apertures, for 
the passage of nutrient vessels; while on the posterior surface is a single large, 
irregular aperture, or occasionally more than one, for the exit of veins from the 
body of the vertebra-the venae basis vertebrae. 
Pedicles.-The pedicles are two short, thick pieces of bone, which project 
backward, one on each side, from the upper part of the body of the vertebra, at 
the line of junction of its posterior and lateral surfaces. Each pedicle (radix 
arcus vertebra?) is a root of the vertebral arch. The concavities above and below 
the pedicles are the superior and inferior intervertebral notches or grooves (incisura 
vertebralis superior et inferior); they are four in number, two on each side, the 
inferior ones being generally the deeper. When the vertebrae are articulated the 
notches of each contiguous pair of bones form the intervertebral foramina (fora- 
mina intervertebralia), which communicate with the spinal canal and transmit 
the spinal nerves and bloodvessels. 
Laminae.-The lamime are two broad plates of bone which complete the neural 
arch by fusing together in the middle line behind. They enclose a foramen, the 
spinal or vertebral foramen (foramen vertebrate), which serves for the protection of 
the spinal cord. When the vertebra* are joined they form, with their ligaments, 
the vertebral canal (spinal or neural canal, canalis vertebralis). The laminae are 
connected to the body by means of the pedicles. Their upper and lower borders 
are rough, for the attachment of the ligamenta subflava. 
Processes. Spinous Process (processus spinosus).-The spinous process projects 
backward from the junction of the two laminae, and serves for the attachment of 
muscles and ligaments. 
Articular Processes.-The articular processes (zyg apophyses), four in number, 
two on each side, spring from the junction of the pedicles with the laminae. Each 
superior process (processus articularis superior) projects upward, its articular 
surface (facies articularis superior) being directed more or less backward; each 
inferior process (processus articularis inferior) projects downward, its articular 
surface (facies articularis inferior) looking more or less forward.1 
Transverse Processes (processus transversi).-The transverse processes, two in 
number, project one at each side from the point where the lamina joins the 
pedicle, between the superior and inferior articular processes. They also serve 
for the attachment of muscles and ligaments. 
The Cervical Vertebrae (Vertebrae Cervicales) (Fig. 15). 
The cervical vertebrae are smaller than those in any other region of the spine, 
and may be readily distinguished by the foramen in the transverse process, which 
does not exist in the transverse process of either a dorsal or lumbar vertebra. 
Body.-The body (centrum) is small, comparatively dense, and broader from 
side to side than from before backward. The anterior and posterior surfaces 
are flattened and of equal depth; the former is placed on a lower level than the 
latter, and its inferior border is prolonged downward, so as to overlap the upper 
and fore part of the vertebra below. Its upper surface is concave transversely, 
and presents a projecting lip on each side; its lower surface is convex from side 
to side, concave from before backward, and presents laterally a shallow concavity 
which receives the corresponding projecting lip of the adjacent vertebra. 
Pedicles.-The pedicles are directed outward and backward, and are 
attached to the body midway between the upper and lower borders, so that 
the superior intervertebral notch is as deep as the inferior, but it is, at the same 
time, narrower. 
1 It may, perhaps, be as well to remind the reader that the direction of a surface is determined by that of a 
line drawn at right angles to it. 50 
THE SKELETON 
Laminae.-The lamime are narrow, long, thinner above than below, and 
overlap each other, enclosing the spinal foramen, which is very large, and of a 
triangular form. 
Processes. Spinous Process.-The spinous process is short, and bifid at the 
extremity, to afford greater extent of surface for the attachment of muscles, the 
two divisions being often of unequal size. They increase in length from the fourth 
to the seventh vertebra. 
Anterior tubercle of trans- 
verse process.' 
Costal cartilage. 
Costo-transverse foramen for 
vertebral artery and vein and' 
sympathetic plexus.i 
Body 
Transverse process. 
Posterior tubercle of' 
transverse process. 
Peaicle 
Spinal Foramen 
Superior articular 
process. 
v 
■Inferior articular process. 
Spinous 
process. 
Fig. 15.-Cervical vertebra. 
Articular Processes.-The articular processes are flat, oblique, and of an oval 
form: the superior are directed backward and upward; the inferior forward and 
downward. 
Transverse Processes.-The transverse processes are short, directed down- 
ward, outward, and forward, bifid at their extremity, and marked by a 
groove along their upper surface, which runs downward and outward from the 
superior intervertebral notch and serves for the transmission of one of the cer- 
vical nerves. They are situated in front of the articular processes and on the 
outer side of the pedicles. The transverse processes are pierced at their base by 
a foramen, for the transmission of the vertebral artery, vein, and a plexus of 
sympathetic nerves. This foramen is known as the transverse foramen, the costo- 
transverse foramen, and the vertebrarterial foramen (foramen transversariuni). 
Each process is formed by two roots: the anterior root, sometimes called the 
costal process, arising from the side of the body, and is the homologue of the rib 
in the dorsal region of the spine; the posterior root springs from the junction of 
the pedicle with the lamina, and corresponds with the transverse process in the 
dorsal region. It is by the junction of the two that the foramen for the vertebral 
vessels is formed. The extremity of each of the anterior roots forms the anterior 
tubercle (tuberculum anterius) and the extremity of each of the posterior roots the 
posterior tubercle (tuberculum posterius} of the transverse processes.1 
The peculiar vertebrae in the cervical regions are the first, or atlas; the second, 
or axis; and the seventh, or vertebra prominens. The great modifications in the 
form of the atlas and axis are designed to admit of the nodding and rotatory 
movements of the head. 
Atlas.-The atlas (Fig. 16) is so named from supporting the globe of the head. 
The chief peculiarities of this bone are that it has neither body nor spinous process. 
The body is detached from the rest of the bone, and forms the odontoid process of 
_ 1 The anterior tubercle of the transverse process of the sixth cervical vertebra is of large size, and is some- 
times known as " Chassaignac's " or the "carotid tubercle" (tuberculum caroticum). It is in close relation 
with the carotid artery, which lies in front and a little external to it; so that, as was first pointed out by 
Chassaignac, the vessel can with ease be compressed against it. THE CERVICAL VERTEBRAE 
51 
the second vertebra; while the parts corresponding to the pedicles join in front to 
form the anterior arch. The atlas is ring-like, and consists of an anterior arch, a 
posterior arch, and two lateral masses. The anterior arch (arcus anterior) forms about 
one-fifth of the ring; its anterior surface is convex, and presents about its centre a 
tubercle (tuberculum anterius), for the attachment of the Longus colli muscle; pos- 
teriorly it is concave, and marked by a smooth, oval facet, called the circular facet 
(fovea dentis), covered with cartilage, for articulation with the odontoid process of the 
Diagram of section of odontoid 
process. 
Tubercle.- 
Diagram of section of 
transverse ligament. 
Transverse 
process' 
Foramen for 
vertebral artery. 
Groove for vertebral artery 
and 1st cervical nerve. 
Rudimentary spinous process.. 
Fig. 16.-First cervical vertebra, or atlas. 
axis. The upper and lower borders give attachment to the anterior occipito-atlantal 
and the anterior atlanto-axial ligaments, which connect it with the occipital bone 
above and the axis below. The posterior arch (arcus posterior) forms about two- 
fifths of the circumference of the bone; it terminates behind in a tubercle (tuber- 
culum posterius), which is the rudiment of a spinous process, and gives origin to 
the Rectus capitis posticus minor. The diminutive size of this process prevents 
any interference in the movements between the atlas and the cranium. The pos- 
terior part of the arch presents above and behind a rounded edge for the attach- 
ment of the posterior occipito-atlantal ligament, while in front, immediately 
behind each superior articular process, is a groove (sulcus arteries vertebralis), 
sometimes converted into a foramen by a delicate bony spiculum, which arches 
backward from the posterior extremity of the superior articular process. These 
grooves represent the superior intervertebral notches, and are peculiar from being 
situated behind the articular processes, instead of in front of them, as in the 
other vertebra'. They serve for the transmission of the vertebral artery, which, 
ascending through the foramen in the transverse process, winds round the lateral 
mass in a direction backward and inward. They also transmit the suboccipital 
(first spinal) nerve. On the under surface of the posterior arch, in the same 
situation, are two other grooves, placed behind the lateral masses, and repre- 
senting the inferior intervertebral notches of other vertebrae. They are much 
less marked than the superior. The lower border also gives attachment to the 
posterior atlanto-axial ligament, which connects it with the axis. The lateral 
masses (masses laterales) are the most bulky and solid parts of the atlas, in order 
to support the weight of the head; they present two articulating surfaces above, 
and two below. Each superior process (fovea articularis superior) is of large size, 
oval, concave, and approaches its companion in front, but diverges from it 
behind; it is directed upward, inward, and a little backward, forming a kind of 
cup for the corresponding condyle of the occipital bone. The two processes are 
admirably adapted to the nodding movements of the head. Not infrequently 
they are partially subdivided by a more or less deep indentation, which encroaches 
upon each lateral margin. Each inferior articular process (facies articularis inferior) THE SKELETON 
52 
is circular in form, flattened or slightly concave, and directed downward and 
inward, articulating with the axis. The inferior processes permit the rotatory 
movements. Just below the inner margin of each superior articular surface is 
a small tubercle, for the attachment of the transverse ligament, which, stretching 
across the ring of the atlas, divides it into two unequal parts or arches; the anterior 
or smaller segment receiving the odontoid process of the axis, the posterior allow- 
ing the transmission of the spinal cord and its membranes. This part of the 
spinal canal is of considerable size, to afford space for the spinal cord; and hence 
lateral displacement of the atlas may occur without compression of this structure. 
The transverse processes are of large size, project directly outward and down- 
ward from the lateral masses, and serve for the attachment of special muscles 
which assist in rotating the head. They are long, not bifid, and perforated at 
their base by a canal for the vertebral artery, which is directed from below, 
upward, and backward. 
Odontoid process. 
Bough surface for check ligaments.- 
Articular surface for 
atlas. 
Articular surface for transverse ligament. 
Lamina. 
■Body. 
Spinous process.' 
* Transverse process. 
Inferior articular process. 
Fig. 17.-Second cervical vertebra, or axis. 
Axis.-The axis {epistropheus') (Fig. 17) is the pivot upon which the first 
vertebra, carrying the head, rotates, hence the name, axis. The most distinctive 
character of this bone is the strong, prominent process, tooth-like in form (hence 
the name odontoid process, or dens), which rises perpendicularly from the upper 
surface of the body. The body is deeper in front than behind, and prolonged 
downward anteriorly so as to overlap the upper and fore part of the next 
vertebra. It presents in front a median longitudinal ridge, separating two 
lateral depressions, for the attachment of the Longus colli muscle of either side. 
The odontoid process presents two articulating surfaces covered with cartilage: 
one in front, of an oval form, for articulation with the atlas {facies articularis 
anterior)', another behind {facies articularis posterior), for the transverse ligament 
-the latter frequently encroaching on the sides of the process. The apex is 
pointed, and gives attachment to the middle odontoid ligament {lipamentum 
apicis dentis). Below the apex the process is somewhat enlarged, and presents 
on either side a rough impression for the attachment of the lateral fasciculi of 
the odontoid or check ligaments, which connect it to the occipital bone; the base 
of the process, where it is attached to the body, is constricted, so as to prevent 
displacement from the transverse ligament, which binds it in this situation to the 
anterior arch of the atlas. Sometimes, however, this process does become dis- 
placed, especially in children, in whom the ligaments are more relaxed: instant 
death is the result of this accident. The internal structure of the odontoid process 
is more compact than that of the body. The pedicles are broad and strong, espe- 
cially their anterior extremities, which coalesce with the sides of the body and the THE THORACIC OR DORSAL VERTEBRAE 
53 
root of the odontoid process. 1 he laminae are thick and strong, and the spinal 
foramen large, but smaller than that of the atlas. The transverse processes are very 
small, not bifid, and each is perforated by the foramen for the vertebral artery, 
which is directed obliquely upward and outward. The superior articular surfaces 
(jacies articulares superiores) are round, slightly convex, directed upward and 
outward, and are peculiar in being supported on the body, pedicles, and trans- 
verse processes. The inferior 
articular surfaces facies articu- 
lares inferiores) have the same 
direction as those of the other 
cervical vertebrae. The superior 
intervertebral notches are very 
shallow, and He behind the artic- 
ular processes; the inferior in 
front of them, as in the other 
cervical vertebrae. The spinous 
process is of large size, very 
strong, deeply channelled on its 
under surface, and presents a 
bifid, tubercular extremity for 
the attachment of muscles which 
serve to rotate the head upon 
the spine. 
Seventh Cervical (Fig. 18).- 
The most distinctive character 
of this vertebra is the existence 
of a very long and prominent 
spinous process; hence the name vertebra prominens. This process is thick, nearly 
horizontal in direction, not bifurcated, and has attached to it the lower end of the 
ligamentum nuchae. The transverse process is usually of large size, its posterior 
tubercles are large and prominent, while the anterior are small and faintly marked; 
its upper surface has usually a hollow groove, and it seldom presents more than a 
trace of bifurcation at its extremity. The foramen in the transverse process is 
sometimes as large as in the other cervical vertebrae, but is usually smaller on one 
or both sides, and is sometimes wanting. On the left side it occasionally gives 
passage to the vertebral artery; more frequently the vertebral vein traverses it on 
both sides; but the usual arrangement is for both artery and vein to pass in front 
of the transverse process, and not through the foramen. Occasionally the anterior 
root of the transverse process exists as a separate bone, and attains a large size. 
It is then known as a cervical rib. 
Body. 
Anterior root. 
Spinal 
foramen. 
Fig. 18.-Seventh cervical vertebra, or vertebra prominens. 
Spinous process. 
The Thoracic or Dorsal Vertebrae (Vertebrae Thoracales). 
The dorsal vertebrae are intermediate in size between those in the cervical and 
those in the lumbar region, and increase in size from above downward, the upper 
vertebrae in this segment of the spine being much smaller than those in the 
lower part of the region. The dorsal vertebrae may be at once recognized by the 
presence on the sides of the body of one or more facets or half-facets for the heads 
of the ribs. 
Bodies.-The bodies of the dorsal vertebrae resemble those in the cervical and 
lumbar regions at the respective ends of this portion of the spine; but in the middle 
of the dorsal region their form is very characteristic, being heart-shaped, and as 
broad in the anteroposterior as in the lateral direction. They are thicker behind 
than in front, flat above and below, convex and prominent in front, deeply con- THE SKELETON 
54 
cave behind, slightly constricted in front and at the sides, and marked on each 
side, near the root of the pedicle, by two demi-facets, one above, the other below 
(jovea costalis superior et inferior). These are covered with cartilage in the recent 
state, and, when articulated with the adjoining vertebrae, form, with the inter- 
vening fibro-cartilage, oval surfaces for the reception of the heads of the corre- 
sponding ribs. The tenth, eleventh, and twelfth dorsal vertebrae each possesses 
one complete facet for the head of the rib, instead of two demi-facets. 
Superior articular process.. 
De mi-facet for head of rib. 
Trans. 
Proc. 
Facet for tubercle of rib. 
Demi-facet for head of rib. 
Inferior articular process. 
Fig. 19.-A dorsal vertebra. 
Pedicles.-The pedicles are directed backward, and the inferior intervertebral 
notches are of large size, and deeper than in any other region of the spine. 
Laminae.-The laminae are broad, thick, and imbricated-that is to say, over- 
lapping one another like tiles on a roof. The spinal foramen is small, and of a 
circular form. 
Processes. Spinous Processes.-Each spinous process is long, triangular on 
transverse section, directed obliquely downward, and terminates in a tubercular 
extremity. They overlap one another from the fifth to the eighth vertebra, but 
are less oblique in direction above and below. 
Articular Processes.-The articular processes are flat, nearly vertical in 
direction, and project from the upper and lower part of the pedicles; the 
superior being directed backward and slightly outward and upward, the inferior 
forward and a little inward and downward. 
Transverse Processes.-The transverse processes arise from the same parts 
of the arch as the posterior roots of the transverse processes in the neck, and 
are situated behind the articular processes and pedicles; they are thick, strong, 
and of great length, directed obliquely backward and outward, presenting a 
clubbed extremity, which is tipped on its anterior part by a small concave surface, 
for articulation with the tubercle of a rib (javea costalis transversalis\ The 
twelfth, the eleventh, and sometimes the tenth dorsal vertebra has no facet on 
the transverse process. Besides the articular facet for the rib, three indistinct 
tubercles may be seen arising from the transverse processes: one at the upper 
border, one at the lower border, and one externally. In man they are compara- 
tively of small size, and serve only for the attachment of muscles. But in some 
animals they attain considerable magnitude, either for the purpose of more closely THE THORACIC OR DORSA^ VERTEBRAE 
55 
connecting the segments of this portion of the spine or for muscular and liga- 
mentous attachment. 
The peculiar dorsal vertebrie are the first, ninth, tenth, eleventh, and twelfth 
(Fig. 20). 
( An entire facet above; 
| a demi-facet below. 
-A demi-facet above. 
One entire facet. 
An entire facet. 
No facet on transverse 
process, which is ru- 
dimentary. 
An entire facet. 
No facet on trans- 
verse process. 
Inferior articular 
process, convex 
and turned out- 
ward. 
Fig. 20.-Peculiar dorsal vertebrae. 
First Dorsal Vertebra.-The first dorsal vertebra presents, on each side of 
the body, a single entire articular facet for the head of the first rib and a half 
facet for the upper half of the second. The body is like that of a cervical vertebra, 
being broad transversely its upper surface is concave, and lipped on each side. 
The articular surfaces are oblique, and the spinous process thick, long, and almost 
horizontal. 
Ninth Dorsal Vertebra.-The ninth dorsal has no demi-facet below. In some 
subjects, however, the ninth has two demi-facets on each side; when this occurs 
the tenth has only a demi-facet at the upper part. 56 
Tenth Dorsal Vertebra.-The tenth dorsal has (except in the cases just men- 
tioned) an entire articular facet on each side, above, which is partly placed on 
the outer surface of the pedicle. It has no demi-facet below. 
Eleventh Dorsal Vertebra.-In the eleventh dorsal the body approaches in its 
form and size to the lumbar. The articular facets for the heads of the ribs, one 
on each side, are of large size, and placed chiefly on the pedicles, which are 
thicker and stronger in this and the next vertebra than in any other part of the 
dorsal region. The spinous process is short, and nearly horizontal in direction. 
The transverse processes are very short, tubercular at their extremities, and have 
no articular facets for the tubercles of the ribs. 
Twelfth Dorsal Vertebra.-The twelfth dorsal has the same general characters 
as the eleventh, but may be distinguished from it by the inferior articular processes, 
being convex and turned outward, like those of the lumbar vertebra?; by the 
general form of the body, laminae, and spinous process, approaching to that of 
the lumbar vertebrae; and by the transverse processes being shorter, and marked 
by three elevations, the superior, inferior, and external tubercles, which corre- 
spond to the mammillary, accessory, and transverse processes of the lumbar ver- 
tebrae. Traces of similar elevations are usually to be found upon the other dorsal 
vertebrae (yide ut supra). 
THE SKELETON 
The Lumbar Vertebrae (Vertebrae Lumbales). 
The lumbar vertebrae (Fig. 21) are the largest segments of the vertebral 
column, and can at once be distinguished by the absence of the foramen in 
the transverse process, the characteristic point of the cervical vertebrae, and by 
the absence of any articulating facet on the side of the body, the distinguishing 
mark of the dorsal vertebrae. 
Superior articular process. 
Fig. 21.-Lumbar vertebra. 
Body.-The body is large, and has a greater diameter from side to side than 
from before backward, slightly thicker in front than behind, flattened or slightly 
concave above and below, concave behind, and deeply constricted in front and at 
the sides, presenting prominent margins, which afford a broad basis for the sup- 
port of the superincumbent weight. 
Pedicles.-The pedicles are very strong, directed backward from the upper 
part of the bodies; consequently, the inferior intervertebral notches are of con- 
siderable depth. 
Laminae.-The laminae are broad, short, and strong, and the spinal fora- 
men triangular, larger than in the dorsal, smaller than in the cervical, region. THE LUMBAR VERTEBRA 
57 
Processes. Spinous Processes.-The spinous processes are thick and broad, 
somewhat quadrilateral, horizontal in direction, thicker below than above, and 
terminating by a rough, uneven border. 
Articular Processes.-The superior articular processes are concave, and look 
backward and inward; the inferior are convex, and look forward and outward; 
the former are separated by a much wider interval than the latter, embracing 
the lower articulating processes of the vertebra above. 
Transverse Processes.-The transverse processes are long, slender, directed 
transversely outward in the upper three lumbar vertebrae, slanting a little upward 
in the lower two. They are situated in front of the articular processes, instead 
of behind them, as in the dorsal vertebrae, and are homologous with the ribs. Of 
the three tubercles noticed in connection with the transverse processes of the 
twelfth dorsal vertebra, the superior one on each side becomes connected in this 
region with the back part of the superior articular process, and has received the 
Inf. articular process. 
Costal process. 
Mammillary process. 
Accessory process. 
Sup. articular process. 
Fig. 22.-Lumbar vertebra. 
name of mammillary process [processus mammillari s)-, the inferior is represented 
by a small process pointing downward, situated at the back part of the base of 
the transverse process, and called the accessory process [processus accessorius'): 
these are the true transverse processes, which are rudimental in this region of 
the spine. The external one is the so-called transverse process, the homologue 
of the rib, and hence sometimes called the costal process [processus costarius) 
(Fig. 22). Although in man the costal processes are comparatively small, in some 
animals they attain considerable size, and serve to lock the vertebra? more 
closely together. 
Fifth Lumbar Vertebra.-The fifth lumbar vertebra is characterized by having 
the body much thicker in front than behind, which accords with the prominence 
of the sacro-vertebral articulation; by the smaller size of its spinous process; by 
the wide interval between the inferior articulating processes; and by the greater 
size and thickness of its transverse processes, which spring from the body as well 
as from the pedicles. THE SKELETON 
58 
Structure of the Vertebrae.-The body is composed of light, spongy, cancel- 
lous tissue, having a thin coating of compact tissue on its external surface per- 
forated by numerous orifices, some of large size, for the passage of vessels; its 
interior is traversed by one or two large canals, for the reception of veins, which 
converge toward a single large, irregular aperture or several small apertures at the 
posterior part of the body of each bone. The arch and processes projecting from 
it have, on the contrary, an exceedingly thick covering of compact tissue (Fig. 23). 
Fig 23.-Bony structure of a lumbar vertebra. (Poirier and Charpy.) 
Development.-Each vertebra is formed of four primary centres of ossification 
(Fig. 24), one for each lamina and its processes, and two for the body.1 Ossifica- 
tion commences in the laminae about the sixth week of foetal life, in the situation 
where the transverse processes afterward project, the ossific granules shooting 
backward to the spine, forward into the pedicles, and outward into the transverse 
and articular processes. Ossification in the body commences in the middle of 
the cartilage about the eighth week by two closely approximated centres, which 
By 4 primary centres. 
2 for body (8th week). 
By 4 secondary centres. 
Ifor each lamina (6th week). 
1 for each trans- 
verse process, 
16 years. 
By 2 additional plates. 
Fig. 24.-Development of a vertebra. 
1 for upper surface 
of body, 
.1 for under surface 
of body, 
21 years. 
2 (sometimes 1) for spinous process (16 years). 
Fig. 25. 
Fig. 26. 
speedily coalesce to form one central ossific point. According to some authors, 
ossification commences in the laminae only in the upper vertebrae-i. e., in the 
cervical and upper dorsal. The first ossific points in the lower vertebrae are those 
which are to form the body, the osseous centres for the laminae appearing at a 
subsequent period. At birth these three pieces are perfectly separate. During 
the first year the laminae become united behind, the union taking place first in 
the lumbar region and then extending upward through the dorsal and lower cer- 
vical regions. About the third year the body is joined to the arch on each side in 
such a manner that the body is formed from the three original centres of ossifica- 
1 By many observers it is asserted that the bodies of the vertebra are developed from a single centre which 
speedily becomes bilobed, so as to give the appearance of two nuclei; but that there are two centres, at all 
events sometimes, is evidenced by the fact that the two halves of the body of the vertebra may remain distinct 
throughout life and be separated by a fissure through which a protrusion of the spinal membrane may take 
place, constituting an anterior spina bifida. THE LUMBAR VERTEBRAE 
59 
tion, the amount contributed by the pedicles increasing in extent from below 
upward. Thus the bodies of the sacral vertebrae are formed almost entirely from 
the central nuclei; the bodies of the lumbar are formed laterally and behind by the 
pedicles; in the dorsal region the pedicles advance as far forward as the articular 
depressions for the head of the ribs, forming these cavities of reception; and in 
the neck the lateral portions of the bodies are formed entirely by the advance of 
the pedicles. The line along which union takes place between the body and the 
neural arch is named neuro-central suture. Before puberty no other changes occur, 
excepting a gradual increase in the growth of these primary centres; the upper 
and under surfaces of the bodies and the ends of the transverse and spinous pro- 
cesses being tipped with cartilage, in which ossific granules are not as yet deposited. 
At sixteen years (Fig. 26) three secondary centres appear, one for the tip of 
each transverse process, and one for the extremity of the spinous process. In 
some of the lumbar vertebrae, especially the first, second, and third, a second 
ossifying centre appears at the base of the spinous process. At twenty-one years 
(Fig. 25) a thin, circular, epiphysial plate of bone is formed in the layer of cartilage 
situated on the upper and under surfaces of the body, the former being the thicker 
of the two. All these become joined, and the bone is completely formed between 
the twenty-fifth and thirtieth year of life. 
Exceptions to this mode of development occur in the first, second, and seventh 
cervical, and in the vertebra? of the lumbar region. 
Atlas (Fig. 27).-The number of centres of ossification of the atlas is very vari- 
able. It may be developed from two, three, four, or five centres. The most 
frequent arrangement is by three 
centres. Two of these are destined 
for the two lateral or neural masses, 
the ossification of which commences 
about the seventh week near the 
articidar processes, and extend 
backward; these portions of bone 
are separated from one another be- 
hind, at birth, by a narrow interval 
filled in with cartilage. Between 
the third and fourth years they unite 
either directly or through the me- 
dium of a separate centre developed 
in the cartilage in the middle line. 
The anterior arch, at birth, is al- 
together cartilaginous, and in this 
a separate nucleus appears about 
the end of the first year after birth, 
and, extending laterally, joins the 
neural processes in front of the pedi- 
cles. Sometimes there are two nu- 
clei developed in the cartilage, one 
on either side of the median line, 
which join to form a single mass. 
And occasionally there is no sepa- 
rate centre, but the anterior arch is formed by the gradual extension forward 
and ultimate junction of the two neural processes. 
Axis.-The axis (Fig. 28) is developed by seven centres. The body and arch 
of this bone are formeci in the same manner as the corresponding parts in the other 
vertebrae: one centre (or two, which speedily coalesce) for the lower part of the 
body, and one for each lamina. The centres for the laminae appear about the 
By 3 centres. 
1 for anterior arch {1st year), 
not constant. 
' 1 for each 
lateral mass 
before birth. 
Fig. 27.-Atlas. 
By 7 centres. 
2d year. 
6th month. 
1 for each lateral mass. 
1 for body (4th month). 
Exceptional cases. 
1 for under surface of 
body. 
2 additional centres. 
Fig. 28.-Axis. 
for tubercles on superior articular process. 
Fig. 29.-Lumbar vertebra. THE SKELETON 
60 
seventh or eighth week, that for the body about the fourth month. The odontoid 
process consists originally of an extension upward of the cartilaginous mass in 
which the lower part of the body is formed. At about the sixth month of foetal 
life two osseous nuclei make their appearance in the base of this process; they 
are placed laterally, and join before birth to form a conical bilobed mass deeply 
cleft above; the interval between the cleft and the summit of the process is formed 
by a wedge-shaped piece of cartilage, the base of the process being separated 
from the body by a cartilaginous interval, which gradually becomes ossified at 
its circumference, but remains cartilaginous in its centre until advanced age.1 
Finally, as Humphry has demonstrated, the apex of the odontoid process has 
a separate nucleus, which appears in the second year and joins about the twelfth 
year. In addition to these there is a secondary centre for a thin epiphysial plate 
on the under surface of the body of the bone. J. Bland Sutton and others main- 
tain that the odontoid process is the "dissociated body of the atlas."2 
Seventh Cervical.-The anterior or costal part of the transverse process of the 
seventh cervical is developed from a separate osseous centre at about the sixth 
month of foetal life, and joins the body and posterior division of the transverse 
process between the fifth and sixth years. Sometimes this process continues as 
a separate piece, and, becoming lengthened outward, constitutes what is known 
as a cervical rib. This separate ossific centre for the costal process has also been 
found in the fourth, fifth, and sixth cervical vertebrae. 
Lumbar Vertebrae.-The lumbar vertebrae (Fig. 29) have two additional centres 
(besides those peculiar to the vertebrae generally) for the mammillary tubercles, 
which project from the back part of the superior articular processes. The trans- 
verse process of the first lumbar is sometimes developed as a separate piece, which 
may remain permanently unconnected with the remaining portion of the bone, 
thus forming a lumbar rib-a peculiarity that is rarely met with. 
Progress of Ossification in the Spine Generally.-Ossification of the laminae of 
the vertebrae commences in the cervical region of the spine, and proceeds gradually 
downward. Ossification of the bodies, on the other hand, commences a little 
below the centre of the spinal column (about the ninth or tenth dorsal vertebra), 
and extends both upward and downward. Although the ossific nuclei make their 
first appearance in the lower dorsal vertebrae, the lumbar and first sacral ver- 
tebrae are those in which these nuclei are largest at birth. 
Attachment of Muscles.-To the Atlas are attached nine pairs: the Longus 
colli, Rectus capitis anticus minor, Rectus lateralis, Obliquus capitis superior and 
inferior, Splenius colli, Levator anguli scapulae, First Intertransverse, and Rectus 
capitis posticus minor. 
To the Axis are attached eleven pairs: the Longus colli, Levator anguli scapulae, 
Splenius colli, Scalenus medius, Transversalis colli, Intertransversales, Obliquus 
capitis inferior, Rectus capitis posticus major, Semispinalis colli, Multifidus spinae, 
Interspinales. 
To the remaining vertebrae, generally, are attached thirty-five pairs and a 
single muscle: anteriorly, the Rectus capitis anticus major, Longus colli, Scalenus 
anticus medius and posticus, Psoas magnus and parvus, Quadratus lumborum, 
Diaphragm, Obliquus abdominis internus, and Transversalis abdominis; pos- 
teriorly, the Trapezius, Latissimus dorsi, Levator anguli scapulae, Rhomboideus 
major and minor, Serratus posticus superior and inferior, Splenius, Erector spinae, 
Ilio-costalis, Longissimus dorsi, Spinalis dorsi, Cervicalis ascendens, Transversalis 
colli, Trachelo-mastoid, Complexus, Biventer cervicis, Semispinalis dorsi and colli, 
Multifidus spinae, Rotatores spinae, Interspinales,Supraspinales, Intertransversales, 
Levatores costarum. 
1 See Cunningham, Jour. Anat., vol. xx. p. 238. 2 Ligaments: their Nature and Morphology. THE SACRAL AND COCCYGEAL VERTEBRA 
61 
The Sacral and Coccygeal Vertebrse (False or Immovable Vertebrae). 
The sacral and coccygeal vertebrae consist, at an early period of life, of nine 
separate pieces, which are united in the adult so as to form two bones, five enter- 
ing into the formation of the sacrum, four into that of the coccyx. Occasionally, 
the coccyx consists of five bones.1 
Sacrum (os sacrum).-The os sacrum (sacer, sacred), the sacred bone. 
So called, according to some, because it was the part selected in sacrifices. 
Another view is that the name is derived from an opinion of the Jewish rabbis, 
that this part of the skeleton strongly resists decay and becomes the germ from 
which the new body will be raised. The sacrum is a large, triangular bone (Fig. 
30), situated at the lower part of the vertebral column, and at the upper and 
back part of the pelvic cavity, where it is inserted like a wedge between the two 
innominate bones; its upper part or base articulating with the last lumbar ver- 
tebra, its apex with the coccyx. It is composed of five segments of bone (sacral 
vertebrae, or vertebra; sacrales). The sacrum is curved upon itself, and placed 
very obliquely, its upper extremity projecting forward, and forming, with the 
last lumbar vertebra, a very prominent angle, called the promontory (promontorium), 
or sacro-vertebral angle; while its central part is directed backward, so as to give 
increased capacity to the pelvic cavity. It presents for examination an anterior and 
posterior surface, two lateral surfaces, a base, an apex, and a central canal. 
Fig. 30.-Sacrum, anterior surface. 
Surfaces. Anterior or Pelvic Surface (jacies pelvina).-The anterior surface 
is concave from above downward, and slightly so from side to side. In the 
middle are seen four transverse ridges (linece transverse), indicating the original 
division of the bone into five separate pieces. The portions of bone intervening 
1 Sir George Humphry describes this as the usual composition of the coccyx. On the Skeleton, p. 456. THE SKELETON 
62 
between the ridges correspond to the bodies of the vertebrae. The body of the first 
segment is of large size, and in form resembles that of a lumbar vertebra; the suc- 
ceeding ones diminish in size from above downward, are flattened from before 
backward, and curved so as to accommodate themselves to the form of the sacrum, 
being concave in front, convex behind. At each end of the ridges above men- 
tioned are seen the anterior sacral foramina (foramina sacralia anteriora), analogous 
to the intervertebral foramina, four in number on each side, somewhat rounded 
in form, diminishing in size from above downward, and directed outward and 
forward; they transmit the anterior branches of the sacral nerves and the lateral 
sacral arteries. External to these foramina is the lateral mass {pars lateralis), 
consisting at an early period of life of separate segments; these become blended, 
in the adult, with the bodies, with each 
other, and with the posterior transverse 
processes. Each lateral mass is traversed 
by four broad, shallow grooves, which 
lodge the anterior sacral nerves as they 
pass outward, the grooves being sepa- 
rated by prominent ridges of bone, which 
give attachment to the slips of the 
Pyriformis muscle. 
If a vertical section is made through 
the centre of the sacrum (Fig. 31), the 
bodies are seen to be united at their cir- 
cumference by bone, a wide interval being 
left centrally, which, in the recent state, 
is filled by intervertebral substance. In 
some bones this union is more complete 
between the lower segments than between 
the upper ones. 
Posterior or Dorsal Surface facies dor- 
salis).-The posterior surface (Fig. 32) is 
convex and much narrower than the ante- 
rior. In the middle line are three or four 
tubercles, which represent the rudimen- 
tary spinous processes of the sacral verte- 
brae. Of these tubercles, the first is 
usually prominent, and perfectly distinct 
from the rest; the second and third are 
either separate or united into a tubercular 
ridge (crista sacralis media), which dimin- 
ishes in size from above downward; the 
fourth usually, and the fifth always, 
remaining undeveloped. The gap which results from failure of the laminae to 
meet in the mid-line is called the hiatus sacralis. External to the spinous pro- 
cesses on each side are the laminae, broad and well marked in the first three 
pieces; sometimes the fourth, and generally the fifth, are only partially developed 
and fail to meet in the middle line. These partially developed laminae are prolonged 
downward as rounded processes, the sacral cornua (cornua sacralia), and are con- 
nected to the cornua of the coccyx. Between them the bony wall of the lower end 
of the sacral canal is imperfect. External to the laminae is a linear series of 
indistinct tubercles representing the articular processes (crista sacrales articulares)} 
the upper pair are large, well developed, and correspond in shape and direction 
to the superior articulating processes of a lumbar vertebra; the second and third 
are small; the fourth and fifth (usually blended together) are situated on each 
Fig. 31.-Vertical section of the sacrum. THE SACRAL AND COCCYGEAL VERTEBRA 
63 
side of the sacral canal and assist in forming the sacral cornua. External to the 
articular processes are the four posterior sacral foramina (foramina sacralia pos- 
ter iora); they are smaller in size and less regular in form than the anterior, 
and transmit the posterior branches of the sacral nerves. On the outer side of 
Auricular 
■Latissimus dor si. 
Surface 
Erector spinx. 
Erector spinx. 
Upper half of fifth 
posterior sacral foramen. 
Fig. 32.-Sacrum, posterior surface. 
the posterior sacral foramina is a series of tubercles, the rudimentary transverse 
processes of the sacral vertebrae (or istte sacr ales later ales). The first pair of trans- 
verse tubercles are large, very distinct, and correspond with each superior angle of 
the bone;.they together with the second pair, which are of small size, give attach- 
ment to the horizontal part of the sacro-iliac ligament; the third gives attachment 
to the oblique fasciculi of the posterior sacro-iliac ligaments ; and the fourth 
and fifth to the great sacro-sciatic ligaments. The interspace between the spinous 
and transverse processes on the back of the sacrum presents a wide, shallow 
concavity, called the sacral groove: it is continuous above with the vertebral 
groove, and lodges the origin of the Multifidus spin®. 
Lateral Surface.-The lateral surface, broad above, becomes narrowed into a 
thin edge below. Its upper half presents in front a broad, ear-shaped surface for 
articulation with the ilium. This is called the auricular surface (facies auricularis), 
and in the fresh state is coated with fibro-cartilage. It is bounded posteriorly by 
deep and uneven impressions, for the attachment of the posterior sacro-iliac liga- 
ments. The chief prominence is called the tuberosity (tuberositas sacralis). The 
lower half is thin and sharp, and terminates in a projection called the inferior lateral 
angle; below this angle is a notch, which is converted into a foramen by articula- 
tion with the transverse process of the upper piece of the coccyx, and transmits 
the anterior division of the fifth sacral nerve. This lower, sharp border gives 
attachment to the greater and lesser sacro-sciatic ligaments, and to some fibres 
of the Gluteus maximus posteriorly, and to the Coccygeus in front. THE SKELETON 
64 
Base (basis oss. sacri).-The base of the sacrum, which is broad and expanded, is 
directed upward and forward. In the middle is seen a large oval articular surface, 
which is connected with the under surface of the body of the last lumbar vertebra 
by a fibro-cartilaginous disk. It is bounded behind by the large, triangular orifice 
of the sacral canal. The orifice is formed behind by the laminae and spinous process 
of the first sacral vertebra: the superior articular processes project from it on each 
side; they are oval, concave, directed backward and inward, like the superior 
articular processes of a lumbar vertebra; and in front of each articular process is 
an intervertebral notch, which forms the lower part of the foramen between the 
last lumbar and first sacral vertebra. Lastly, on each side of the large oval articular 
plate is a broad and flat triangular surface of bone, which extends outward, 
supports the Psoas magnus muscle and lumbo-sacral cord, and is continuous 
on each side with the iliac fossa. This is called the ala of the sacrum (ala 
sicralis), and gives attachment to a few of the fibres of the Iliacus muscle. The 
posterior part of the ala represents the transverse process of the first sacral 
segment. 
Apex (apex oss. sacri).-The apex, directed downward and slightly forward, 
presents a small, oval, concave surface for articulation with the coccyx. 
Spinal Canal.-The spinal canal in this region is called the sacral canal (canalis 
sacralis). It runs throughout the greater part of the bone; it is large and tri- 
angular in form above, small and flattened, from before backward, below. In 
this situation its posterior wall is incomplete, from the non-development of the 
laminae and spinous processes (hiatus sacralis). It lodges the sacral nerves, 
and is perforated by the anterior and posterior sacral foramina, through which 
these pass out. 
Structure.-It consists of much loose, spongy tissue within, invested externally 
by a thin layer of compact tissue. 
Differences in the Sacrum of the Male and Female.-The sacrum in the 
female is shorter and wider than in the male; the lower half forms a greater 
angle with the upper, the upper half of the bone being nearly straight, the lower 
half presenting the greatest amount of curvature. The bone is also directed more 
obliquely backward, which increases the size of the pelvic cavity; but the sacro- 
vertebral angle projects less. In the male the curvature is more evenly dis- 
tributed over the whole length of the bone, and is altogether greater than in 
the female. 
Peculiarities of the Sacrum.-This bone, in some cases, consists of six pieces; 
occasionally, the number is reduced to four. Sometimes the bodies of the first 
and second segments are not joined or the laminae and spinous processes have not 
coalesced. Occasionally, the upper pair of transverse tubercles are not joined to 
the rest of the bone on one or both sides; and, lastly, the sacral canal may be open 
for nearly the lower half of the bone, in consequence of the imperfect development 
of the laminae and spinous processes. The sacrum, also, varies considerably with 
respect to its degree of curvature. From the examination of a large number of 
skeletons it would appear that in one set of cases the anterior surface of this bone 
was nearly straight, the curvature, which was very slight, affecting only its lower 
end. In another set of cases the bone was curved throughout its whole length, 
but especially toward its middle. Tn a third set the degree of curvature was less 
marked, and affected especially the lower third of the bone. 
Development (Fig. 33).-The sacrum, formed by the union of five vertebrae, 
has thirty-five centres of ossification. 
The bodies of the sacral vertebrae have each three ossific centres: one for the 
central part, and one for the epiphysial plates on its upper and under surface. 
Occasionally the primary centres for the bodies of the first and second piece of the 
sacrum are double. SACRAL AND COCCYGEAL VERTEBRAE 
65 
The arch of each sacral vertebra is developed by two centres, one for each 
lamina. These unite with each other behind, and subsequently join the body. 
The lateral masses have six additional centres, two for each of the first three 
vertebrae. These centres make their appearance above and to the outer side of 
the anterior sacral foramina (Fig. 33), and are developed into separate segments 
(Fig. 34); they are subsequently blended with each other, and with the bodies 
and transverse processes to form the lateral mass. 
Lastly, each lateral surface of the sacrum is developed by two epiphysial plates 
(Fig. 35): one for the auricular surface, and one for the remaining part of the 
thin lateral edge of the bone. 
Two epiphysial laminae 
for each lateral surfaced 
Additional centres 
for the first three pieces.* 
At birth. 
At 
25th year. 
At years. 
Fig. 34. 
Fig. 33.-Development of the sacrum. 
Fig. 35. 
Period of Development.-At about the eighth or ninth week of foetal life ossifi- 
cation of the central part of the bodies of the first three vertebrae commences, 
and at a somewhat later period that of the last two. Between the sixth and 
eighth months ossification of the laminae takes place; and at about the same 
period the centres for the lateral masses for the first three sacral vertebrae make 
their appearance. The period at which the arch becomes completed by the junc- 
tion of the laminae with the bodies in front and with each other behind varies in 
different segments. The junction between the laminae and the bodies takes place 
first in the lower vertebrae as early as the second year, but is not affected in the 
uppermost until the fifth or sixth year. About the sixteenth year the epiphyses 
for the upper and under surfaces of the bodies are formed, and between the eigh- 
teenth and twentieth years those for each lateral surface of the sacrum make their 
appearance. The bodies of the sacral vertebrae are, during early life, separated 
from each other by intervertebral disks. But about the eighteenth year the two 
lowest segments become joined together by ossification extending through the 
disk. This process gradually extends upward until all the segments become 
united, and the bone is completely formed from the twenty-fifth to the thirtieth 
year of life. 
Articulations.-With four bones: the last lumbar vertebra, coccyx, and the 
two innominate bones. 
Attachment of Muscles.-To eight pairs: in front, the Pyriformis and Coc- 
cygeus, and a portion of the Iliacus to the base of the bone; behind, the Gluteus 
maximus, Latissimus dorsi, Multifidus spinae, and Erector spinae, and sometimes 
the Extensor coccygis. 
Coccyx (os coccygis).-The coccyx (xoxxo^, cuckoo), so called from having 
been compared to a cuckoo's beak (Fig. 36), is usually formed of four small 
segments of bone, the most rudimentary parts of the vertebral column (vertebrae 
coccygeae or caudate vertebrae). In each of the first three segments may be traced 
a rudimentary body, articular and transverse processes; the last piece (some- 66 
THE SKELETON 
times the third) is a mere nodule of bone, without distinct processes. All the 
segments are destitute of pedicles, laminae, and spinous processes, and, conse- 
quently, of intervertebral foramina and spinal canal. The first segment is the 
largest; it resembles the lowermost sacral vertebra, and often exists as a separate 
Cornua. 
Rudim. 
trans, 
process. 
Anterior surface. 
Fig. 36.--Coccyx. 
Posterior surface. 
piece; the last three, diminishing in size from above downward, are usually 
blended together so as to form a single bone. The gradual diminution in the size 
of the pieces gives this bone a triangular form, the base of the triangle joining 
the end of the sacrum. It presents for examination an anterior and posterior sur- 
face, two borders, a base, and an apex. 
Surfaces. Anterior Surface.-The anterior surface is slightly concave, and 
marked with three transverse grooves, indicating the points of junction of the 
different pieces. It has attached to it the anterior sacro-coccygeal ligament and 
Levator ani muscle, and supports the lower end of the rectum. 
Posterior Surface.-The posterior surface is convex, marked by transverse grooves 
similar to those on the anterior surface; and presents on each side a lineal row 
of tubercles, the rudimentary articular processes of the coccygeal vertebrae. Of 
these, the superior pair are large, and are called the cornua of the coccyx (cornua 
coccygea); they project upward, and articulate with the cornua of the sacrum, the 
junction between these two bones completing the fifth posterior sacral foramen for 
the transmission of the posterior division of the fifth sacral nerve. 
Borders.-The lateral borders are thin, and present a series of small eminences, 
which represent the transverse processes of the coccygeal vertebne. Of these, 
the first on each side is the largest, flattened from before backward, and often 
ascends to join the lower part of the thin lateral edge of the sacrum, thus com- 
pleting the fifth anterior sacral foramen for the transmission of the anterior 
division of the fifth sacral nerve; the others diminish in size from above down- 
ward, and are often wanting. The borders of the coccyx are narrow, and give 
attachment on each side to the sacro-sciatic ligaments, to the Coccygeus muscles 
in front of the ligaments, and to the Gluteus maximus behind them. 
Base.-The base presents an oval surface for articulation with the sacrum. 
This articulation is known as the sacro-coccygeal symphysis (symphysis sacro- 
coccygea). 
Apex.-The apex is rounded, and has attached to it the tendon of the external 
Sphincter muscle. It is occasionally bifid, and sometimes deflected to one or 
other side. 
Development.-The coccyx is developed by four centres, one for each piece. 
Occasionally one of the first three pieces of this bone is developed by two centres, 
placed side by side. The ossific nuclei make their appearance in the following 
order: in the first segment, shortly after birth; in the second piece, at from five THE VERTEBRAL COLUMN 
67 
to ten years; in the third, from ten to fifteen 
years; in the fourth, from fifteen to twenty 
years. As age advances these various seg- 
ments become united with each other from 
below upward, the union between the first 
and second segments being frequently delayed 
until after the age of twenty-five or thirty. 
At a late period of life, especially in females, 
the coccyx often becomes joined to the end 
of the sacrum. 
Articulation.-With the sacrum. 
Attachment of Muscles.-To four pairs 
and one single muscle : on either side, the 
Coccygeus; behind, the Gluteus maximus 
and Extensor coccygis, when present; at the 
apex, the Sphincter ani; and in front, the 
Levator ani. 
1st cervical 
or Atlas. 
2nd cervical 
or Axis. 
1st dorsal. 
The Vertebral Column or Spine in General. 
The spinal column (columna vertebralis), 
formed by the junction of the vertebrae, is 
situated in the median line, at the posterior 
part of the trunk; its average length is about 
two feet two or three inches, measuring along 
the curved anterior surface of the column. 
Of this length the cervical part measures 
about five, the dorsal about eleven, the lum- 
bar about seven inches, and the sacrum and 
coccyx the remainder. The female spine is 
about one inch less than that of the male. 
Viewed in front, the ventral surface presents 
two pyramids joined together at their bases, 
the upper one being formed by all the verte- 
bne from the second cervical to the last lum- 
bar, the lower one by the sacrum and coccyx. 
When examined more closely, the upper 
pyramid is seen to be formed of three smaller 
pyramids. The uppermost of these consists 
of the six lower cervical vertebrae, its apex 
being formed by the axis or second cervical, 
its base by the first dorsal. The second 
pyramid, which is inverted, is formed by the 
four upper dorsal vertebrae, the base being at 
the first dorsal, the smaller end at the fourth. 
The third pyramid commences at the fourth 
dorsal, and gradually increases in size to the 
fifth lumbar. 
Viewed laterally (Fig. 37), the spinal column 
presents several curves which correspond to 
the different regions of the column, and are 
called cervical, dorsal, lumbar, and pelvic. 
The cervical curve commences at the apex of 
the odontoid process, and terminates at the 
1st lumbar. 
Sacrum. 
Coccyx. 
Fig. 37.-Lateral view of the spine. 68 
THE SKELETON 
middle of the second dorsal vertebra; it is convex in front, and is the least 
marked of all the curves. The dorsal curve, which is concave forward, com- 
mences at the middle of the second, and terminates at the middle of the twelfth 
dorsal vertebra. Its most prominent point behind corresponds to the spine 
of the seventh dorsal vertebra. The lumbar curve commences at the middle 
of the last dorsal vertebra, and terminates at the sacro-vertebral angle. It is 
convex anteriorly; the convexity of the lower three vertebrae being much greater 
than that of the upper two. The pelvic curve commences at the sacro-verte- 
bral articulation and terminates at the point of the coccyx. It is concave 
anteriorly. The dorsal and pelvic curves are the primary curves, and begin to 
be formed at an early period of foetal life, and are due to the shape of the bodies 
of the vertebrae. The cervical and lumbar curves are compensatory or secondary, 
and are developed after birth in order to maintain the erect position. They are 
due mainly to the shape of the intervertebral disks. 
Some writers teach that the spine has a normal deviation to the right side. 
Quain, Hyrtl, and others maintain this view. The curve is said to be in the 
dorsal region. Bichat assigned muscular action as the chief cause of the curve. 
Most persons use the right arm in preference to the left, especially in making 
long-continued efforts, when the body is curved to the right side. In support 
of this explanation is the observation made by Beclard that in some individuals 
who were left-handed the lateral curvature was directed to the left side. Sappey 
and others deny the existence of this curve. 
The movable part of the spinal column presents for examination an anterior, 
a posterior, and two lateral surfaces; a base, a summit, and the spinal canal. 
Surfaces. Anterior Surface.-The anterior or ventral surface presents the bodies 
of the vertebra? separated in the recent state by the intervertebral disks. The bodies 
are broad in the cervical region, narrow in the upper part of the dorsal, and 
broadest in the lumbar region. The whole of this surface is convex transversely, 
concave from above downward in the dorsal region, and convex in the same 
direction in the cervical and lumbar regions. 
Posterior Surface.-The posterior or dorsal surface presents in the median line 
the spinous processes. These are short, horizontal, with bifid extremities, in the 
cervical region. In the dorsal region they are directed obliquely above, assume 
almost a vertical direction in the middle, and are horizontal below, as are also 
the spines of the lumbar vertebrae. They are separated by considerable intervals 
in the loins, by narrower intervals in the neck, and are closely approximated in 
the middle of the dorsal region. Occasionally one of these processes deviates a 
little from the median line-a fact to be remembered in practice, as irregularities 
of this sort are attendant also on fractures or displacements of the spine. On 
either side of the spinous processes, extending the whole length of the column, 
is the vertebral groove formed by the laminae in the cervical and lumbar regions, 
where it is shallow, and by the lamina? and transverse processes in the dorsal 
region, where it is deep and broad. In the recent state these grooves lodge the 
deep muscles of the back. External to each vertebral groove are the articular 
processes, and still more externally is the transverse process. In the dorsal region 
the latter processes stand backward, on a plane considerably posterior to the 
same processes in the cervical and lumbar regions. In the cervical region the 
transverse processes are placed in front of the articular processes, and on the 
outer side of the pedicles, between the intervertebral foramina. In the dorsal 
region they are posterior to the pedicles, intervertebral foramina, and articular 
processes. In the lumbar region they are placed also in front of the articular 
processes, but behind the intervertebral foramina. 
Lateral Surfaces.-The lateral surfaces are separated from the posterior surface 
by the articular processes in the cervical and lumbar regions, and by the trans- THE VERTEBRAL COLUMN 
69 
verse processes in the dorsal region. These surfaces present in front the sides of 
the bodies of the vertebrae, marked in the dorsal region by the facets for articula- 
tion with the heads of the ribs. More posteriorly are the intervertebral foramina, 
formed by the juxtaposition of the intervertebral notches, oval in shape, smallest 
in the cervical and upper part of the dorsal regions, and gradually increasing in 
size to the last lumbar vertebra. They are situated between the transverse pro- 
cesses in the neck, and in front of them in the back and loins, and transmit the 
spinal nerves. 
Base.-The base of that portion of the vertebral column formed by the twenty- 
four movable vertebrae is formed by the under surface of the body of the fifth 
lumbar vertebra; and the summit by the upper surface of the atlas. 
Spinal Canal (canalis vertebralis).-The vertebral or spinal canal follows the 
different curves of the spine; it is largest in those regions in which the spine 
enjoys the greatest freedom of movement, as in the neck and loins, where it is 
wide and triangular; and is narrow and rounded in the back, where motion is 
more limited. The centre of gravity of the spine is in the upper lumbar region, 
slightly to the right of the median plane (Struthers). 
Surface Form.-The only parts of the vertebral column which lie closely under the skin, and 
so directly influence surface form, are the apices of the spinous processes. These are always distin- 
guishable at the bottom of a median furrow, which, more or less evident, runs down the mesial 
line of the back from the external occipital protuberance above to the middle of the sacrum below. 
In the cervical region the furrow is between the Trapezii muscles; in the back and loins it is between 
the Erector spinae muscles. In the neck the furrow is broad, and terminates in a conspicuous 
projection, which is caused by the spinous process of the seventh cervical vertebra (vertebra 
prominens). Above this the spinous process of the sixth cervical vertebra may sometimes be 
seen to form a projection; the other cervical spines are sunken, and are not visible, though the 
spine of the axis can be felt, and generally also the spines of the third, fourth, and fifth cervical 
vertebrae. In the dorsal region the furrow is shallow, and during stooping disappears, and then 
the spinous processes become more or less visible. The markings produced by these spines are 
small and close together. In the lumbar region the furrow is deep, and the situation of the lumbar 
spines is frequently indicated by little pits or depressions, especially if the muscles in the loins 
are well developed and the spine incurved. They are much larger and farther apart than in the 
dorsal region. In the sacral region the furrow is shallower, presenting a flattened area which 
terminates below at the most prominent part of the posterior surface of the sacrum, formed by 
the spinous process of the third sacral vertebra. At the bottom of the furrow may be felt the 
irregular posterior surface of the bone. Below this, in the deep groove leading to the anus, the 
coccyx may be felt. The only other portions of the vertebral column which can be felt from the 
surface are the transverse processes of three of the cervical vertebrae-viz., the first, the sixth, 
and the seventh. The transverse process of the atlas can be felt as a rounded nodule of bone 
just below and in front of the apex of the mastoid process, along the anterior border of the sterno- 
mastoid. The transverse process of the sixth cervical vertebra is of surgical importance. If 
deep pressure be made in the neck in the course of the carotid artery, opposite the cricoid carti- 
lage, the prominent anterior tubercle of the transverse process of the sixth cervical vertebra can 
be felt. This has been named Chassaignac's tubercle, and against it the carotid artery may be 
most conveniently compressed by the finger. The transverse process of the seventh cervical 
vertebra can also often be felt. Occasionally the anterior root, or costal process, is large and 
segmented off, forming a cervical rib. 
Surgical Anatomy.-It is frequently necessary to locate certain vertebrae. Several of them 
can be easily found and identified. The seventh cervical spine is conspicuously prominent, and 
when the skin above it has been marked with a blue pencil the spine of the sixth cervical above 
and of the first dorsal below may be located. The spine of the third dorsal vertebra is on- a level 
with the root of the spine of the scapula. The spine of the fourth lumbar vertebra is on a level 
with the highest point of the iliac crest. When one or two vertebrae have been definitely recog- 
nized the other ones can be found by counting the spines from a fixed point or from fixed points. 
Over the fifth lumbar spine there is no prominence, but a depression. The third sacral spine 
is on a level with the posterior superior spines of the ilium. The level at which the spinal cord 
terminates should be known to the surgeon if he proposes to tap the dural sac (lumbar puncture), 
for diagnostic or therapeutic purposes or as a preliminary to the injection of cocaine oreucaine 
(spinal anaesthesia). In an adult the cord terminates at the lower border of the first lumbar 
vertebra, and the dural sac terminates opposite the body of the third sacral vertebra. In a child 
the cord terminates opposite the body of the third lumbar vertebra, and the dural sac ends at 70 
THE SKELETON 
about the same level as in an adult. Hence, in either a child or an adult, a puncture below the 
level of the fourth lumbar vertebra will inflict no injury upon the cord. In children the puncture 
is made just beneath the vertebral spine, and in adults about one-half an inch to either side of 
the vertebral spine, although, even in adults, the needle is made to enter the dura in the middle 
line. In either case the needle is directed upward and forward. As previously pointed out, the 
surgical anatomy of an infant's spine is not identical with the surgical anatomy of an adult's 
spine. An infant's spine is larger comparatively than an adult's spine, because the lower limbs 
are less developed in the former (A. H. Tubby). The umbilicus of an infant is opposite the body 
of the fourth lumbar vertebra; in an adult it is opposite the spine of the third lumbar vertebra. 
In an infant the base of the sternum is on a level with the top of the seventh cervical spine, and 
in an adult of the second dorsal spine (A. H. Tubby). 
Occasionally the coalescence of the laminse is not completed, and consequently a cleft is left 
in the arches of the vertebrae, through which a protrusion of the spinal membranes (dura mater 
and arachnoid), and sometimes of the spinal cord itself, takes place, constituting a malformation 
known as spina bifida or hydrorrhachitis. This disease is most common in the lumbosacral 
region; but it may occur in the dorsal or cervical region, or the arches throughout the whole 
length of the canal may remain unapproximated. In some rare cases, in consequence of the 
non-coalescence of the two primary centres from which the body is formed, a similar condition 
may occur in front of the canal, the bodies of the vertebrae being found cleft and the tumor pro- 
jecting into the thorax, abdomen, or pelvis, between the lateral halves of the bodies affected. 
The construction of the spinal column of a number of pieces, securely connected together 
and enjoying only a slight degree of movement between any two individual pieces, though per- 
mitting of a very considerable range of movement as a whole, allows a sufficient degree of 
mobility w'ithout any material diminution of strength. The main joints of which the spine is 
composed, together with the very varied movements to which it is subjected, render it liable to 
sprains, which may complicate other injuries or may exist alone; but so closely are the individual 
vertebrae articulated that these sprains are seldom severe, and an amount of violence sufficiently 
great to produce tearing of the ligaments would tend to cause a dislocation or fracture. The 
further safety of the column and its less liability to injury is provided for by its disposition 
in curves instead of in one straight line. For it is an elastic column, and must first bend before 
it breaks: under these circumstances, being made up of three curves, it represents three columns, 
and greater force is required to produce bending of a short column than of a longer one that is 
equal to it in breadth and material. Again, the safety of the column is provided for by the inter- 
position of the intervertebral disks between the bodies of the vertebra, which act as admirable 
buffers in counteracting the effects of violent jars or shocks. Fracture dislocation of the spine 
may be caused by direct or indirect violence, or by a combination of the two, as when a person, 
falling from a height, strikes against some prominence and is doubled over it. The fractures 
from indirect violence are the more common, and here the bodies of the vertebra are compressed, 
whilst the arches are torn asunder; whilst in fractures from direct violence the arches are com- 
pressed and the bodies of the vertebra separated from each other. It will therefore be seen that 
in both classes of injury the spinal marrow is the part least likely to be injured, and may escape 
damage even where there has been considerable lesion of the bony framework. For, as Mr. 
Jacobson states, "being lodged in the centre of the column, it occupies neutral ground in respect 
to forces which might cause fracture. For it is a law in mechanics that when a beam, as of timber, 
is exposed to breakage and the force does not exceed the limits of the strength of the material, 
one division resists compression, another laceration of the particles, while the third, between 
the two, is in a negative condition."1 Applying this principle to the spine it will be seen that, 
whether the fracture dislocation be produced by direct violence or by indirect force, one segment, 
either the anterior or posterior, will be exposed to compression, the other to laceration, and the 
intermediate part, where the cord is situated, will be in a neutral state. When a fracture dis- 
location is produced by indirect violence the displacement is almost always the same, the upper 
segment being driven forward on the lower, so that the cord is compressed between the body of 
the vertebra below and the arch of the vertebra above. 
The parts of the spine most liable to be injured are (1) the dorso-lumbar region, for this part 
is near the middle of the column, and there is therefore a greater amount of leverage, and more- 
over the portion above is comparatively fixed, and the vertebra which form it, though much 
smaller, have nevertheless to bear almost as great a weight as those below; (2) the cervico-dorsal 
region, because here the flexible cervical portion of the spine joins the more fixed dorsal region; 
and (3) the atlanto-axial region, because it enjoys an extensive range of movement, and, being 
near the skull, is influenced by violence applied to the head. In fracture dislocation spinous 
processes and portions of the laminfe may be removed (laminectomy) in order to free the cord 
from pressure, and to permit the surgeon to explore, to arrest hemorrhage, to remove bone 
fragments, or to apply sutures. Laminectomy is also resorted to in some cases of paraplegia due 
to Pott's disease of the spine. 
1 Holmes's System of Surgery, vol. i. p. 529, 1883. THE OCCIPITAL BONE 
71 
THE SKULL. 
The skeleton of the head is called the skull. The cranium is the skull without 
the mandible. The calvaria or cerebral cranium is the skull without the bones of 
the face. The skull is supported on the summit of the vertebral column, and is 
of an oval shape, wider behind than in front. It is composed of a series of flat- 
tened or irregularly shaped bones which, with one exception (the lower jaw), are 
immovably joined together. It is divided into two parts, the cerebral cranium or 
calvaria and the visceral cranium or face, the former of which constitutes a case 
for the accommodation and protection of the brain, while opening on the face 
are the orifices of the nose and mouth; between the cerebral cranium above and 
the face below the orbital cavities are situated. The cerebral cranium (xpdvo^, a 
helmet) is composed of eight bones-viz., the occipital, two parietal, frontal, two 
temporal, sphenoid, and ethmoid. The face is composed of fourteen bones- 
viz., the two nasal, two superior maxillary, two lachrymal, two malar, two palate, 
two inferior turbinated, vomer, and inferior maxillary or mandible. The ossiculi 
auditus, the teeth, and Wormian bones are not included in this enumeration. 
Occipital. 
Two Parietal. 
Frontal. 
Two Temporal. 
Sphenoid. 
Ethmoid. 
'Cranium, 8 bones 
Skull, 22 bones 
Two Nasal. • 
Two Superior Maxillary. 
Two Lachrymal. 
Two Malar. 
Two Palate. 
Two Inferior Turbinated. 
Vomer. 
Inferior Maxillary or Mandible. 
Face, 14 bones 
The Hyoid Bone, situated at the root of the tongue and attached to the base 
of the skull by ligaments, has also to be considered in this section. 
THE CEREBRAL CRANIUM (CRANIUM CEREBRALE) (THE CALVARIA). 
The Occipital Bone (Os Occipitale). 
The occipital bone (ob, caput, against the head) is situated at the back part 
and base of the cranium, is trapezoid in shape and is much curved on itself (Fig. 
38). It presents at its front and lower part a large oval aperture, the foramen 
magnum (foramen occi pitale magnum), by which the cranial cavity communicates 
with the spinal canal. The portion of bone behind this opening is flat and 
expanded and forms the tabula, tabular portion, or squamous part (squama 
occipitalis); the portion in front is a thick, elongated mass of bone, the basilar 
process (pars basilaris); while on each side of the foramen is situated a lateral 
or condylic portion (pars lateralis), bearing the condyle, by which the bone articu- 
lates with the atlas. The bone presents for examination two surfaces, four borders, 
and four angles. 
Surfaces. External Surface.-'Jhe external surface is convex. Midway between 
the summit of the bone and the posterior margin of the foramen magnum is a 
prominent tubercle, the inion or external occipital protuberance (protuberantia 72 
THE SKELETON 
occipitalis externa, and, descending from it as far as the foramen, a vertical 
ridge, the external occipital crest (crista occipitalis externa). This protuberance 
and crest give attachment to the ligamentum nuchie, and vary in prominence 
in different skulls. Passing outward from the occipital protuberance is a semi- 
circular ridge on each side, the superior curved or superior nuchal line (linea 
nuchce superior). Above this line there is often a second less distinctly 
marked ridge, called the highest curved line (linea nuchce suprema); to it the epi- 
cranial aponeurosis is attached. The bone between these two lines is smoother 
and denser than the rest of the surface. Running parallel with these from the 
middle of the crest is another semicircular ridge on each side, the inferior curved 
or inferior nuchal line (linea nuchce inferior). The surface of the bone above the 
linea suprema is rough and porous, and in the recent state is covered by the 
Linea 
suprema. 
Foramen 
Magnum. 
Tubercles for 
Check 
Ligaments. 
Anterior condyloid 
foramen. 
SUPERIOR 
CONSTRICTOR 
-o/ Pharynx. 
Fig. 38.-Occipital bone. Outer surface. 
Occipitofrontalis muscle. It is called the occipital portion or the planum 
occipitale. The superior and inferior curved lines, together with the surfaces of 
bone between and below them, serve for the attachment of several muscles. 
The superior curved line gives attachment internally to the Trapezius, externally 
to the muscular origin of the Occipitofrontalis, and to the Sternocleidomastoid 
to the extent shown in Fig. 38; the depressions between the curved lines to the 
Coinplexus internally, the Splenius capitis and Obliquus capitis superior exter- 
nally. The inferior curved line and the depressions below it afford insertion to 
the Rectus capitis posticus, major and minor. The portion of the tabula below 
the superior curved line is called the nuchal plane (planum nuchale), and it gives 
attachment to certain of the neck muscles. , 
The foramen magnum (foramen occipitale magnum) is a large, oval aperture, its 
long diameter extending from before backward. It transmits the lower portion THE OCCIPITAL BONE 
73 
of the medulla oblongata and its membranes, the spinal accessory nerves, the 
vertebral arteries, the anterior and posterior spinal arteries, and the occipito- 
axial ligaments. Its back part is wide for the transmission of the medulla, and 
the corresponding margin rough for the attachment of the dura mater enclosing 
it; the fore part is narrower, being encroached upon by the condyles; it has pro- 
jecting toward it, from below, the odontoid process, and its margins are smooth 
and bevelled internally to support the medulla oblongata. The middle of the 
anterior wall of the foramen magnum is called by Broca the basion. The lateral 
or condylic portions {partes later ales') are on either side of the foramen magnum 
and bear the condyles for articulation with the atlas. Each condyle {condylus 
occipitalis) is convex, oval, or reniform in shape, and directed downward and 
outward. The condyles converge in front, and encroach slightly upon the anterior 
segment of the foramen. On the inner border of each condyle is a rough tubercle 
for the attachment of the ligaments {check) which connect this bone with the 
odontoid process of the axis; while external to them is a rough tubercular promi- 
nence, the transverse or jugular process {processus jugularis), channelled in front 
by a deep notch {incisura jugularis), which forms part of the jugular foramen 
or foramen lacerum posterius. The under surface of this process presents an 
eminence {processus intrajugularis) which represents the paramastoid process of 
some mammals. The eminence is occasionally large, and extends as low as the 
transverse process of the atlas. This surface affords attachment to the Rectus 
capitis lateralis muscle and to the lateral occipito-atlantal ligament; its upper or 
cerebral surface presents a deep groove which lodges part of the lateral sinus, 
while its external surface is marked by a quadrilateral rough facet, covered with 
cartilage in the fresh state, and articulating with a similar surface on the petrous 
portion of the temporal bone. On the outer side of each condyle, near its fore 
part, is a foramen, the anterior condyloid foramen {canalis hypoglossi or the hypo- 
glossal canal); it is directed downward, outward, and forward, and transmits the 
hypoglossal nerve, and occasionally a meningeal branch of the ascending pharyn- 
geal artery. This foramen is sometimes double. Behind each condyle is a 
fossa1 {fossa condyloideus), sometimes perforated at the bottom by a foramen, 
the posterior condyloid foramen {canalis condyloideus), for the transmission of a 
vein to the lateral sinus. The basilar process {pars basilaris) is a strong quadri- 
lateral plate of bone, which is wider behind than in front, and is situated in front 
of the foramen magnum. Its under surface, which is rough, presents in the 
median line a tubercular ridge, the pharyngeal spine or tubercle (tubercidum 
pharyngeum), for the attachment of the tendinous raphe and Superior con- 
strictor of the pharynx; and on each side of it rough depressions for the attach- 
ment of the Rectus capitis anticus, major and minor. 
Internal Surface.-The internal or cerebral surface (Fig. 39) is deeply concave. 
The posterior or tabular part is divided by a crucial ridge into four fossa?. The 
two superior fossae receive the occipital lobes of the cerebrum, and present slight 
eminences and depressions corresponding to their convolutions. The two inferior, 
which receive the hemispheres of the cerebellum, are larger than the former, and 
comparatively smooth; both are marked by slight grooves for the lodgement of 
arteries. At the point of meeting of the four divisions of the crucial ridge is an 
eminence, the internal occipital protuberance {protuberantia occipitalis interna). It 
nearly corresponds to that on the outer surface, though it is often on a slightly 
higher level, and is perforated by one or more large vascular foramina. From 
this eminence the superior division of the crucial ridge runs upward to the supe- 
rior angle of the bone; it presents a deep groove, the sagittal sulcus {sidcus sagit- 
1 This fossa presents many variations in size. It is usually shallow, and the foramen small; occasionally 
wanting on one or both sides. Sometimes both fossa and foramen are large, but confined to one side only; 
more rarely, the fossa and foramen are very large on both sides. 74 
THE SKELETON 
tails), for the superior longitudinal sinus. The margins of the groove give attach- 
ment to the falx cerebri. The inferior division, the internal occipital crest (crista 
occipitalis interna), runs to the posterior margin of the foramen magnum, on the 
edge of which it becomes gradually lost; this ridge, which is bifurcated below,serves 
Superior angle. 
8u^>-io 
A?' 
Lateral 
Augie. 
/ 
z 
f 
i 
Fo ramen 
Magn um. 
/ 
C? 
y 
Antr. Condyloid 
foramina. 
z° 
X 
X 
Fig. 39.-Occipital bone. Inner surface. 
Inferior anole. 
for the attachment of the falx cerebelli. It is usually marked by a single groove, 
which commences at the back part of the foramen magnum and lodges the occip- 
ital sinus. Occasionally the groove is double where two sinuses exist. A 
transverse groove (sulcus transversus) passes outward on each side to the lateral 
angle. The grooves are deep channels for the lodgement of the lateral sinuses, their 
prominent margins affording attachment to the tentorium cerebelli.1 At the point 
of meeting of these grooves is a depression, the torcular Herophili,2 placed a little 
to one or the other side of the internal occipital protuberance. More anteriorly 
is the foramen magnum, and on each side of it, but nearer its anterior than its 
posterior part, the internal openings of the anterior condyloid foramen. On the 
superior aspect of the lateral portion of the bone the jugular tubercle (tuberculum 
jugulars) is seen. This corresponds to the portion of bone which roofs in the 
anterior condyloid foramen. The internal openings of the posterior condyloid 
1 Usually one of the transverse grooves is deeper and broader than the other; occasionally, both grooves are 
of equal depth and breadth, or both equally indistinct. The broader of the two transverse grooves is nearly 
always continuous with the vertical groove for the superior longitudinal sinus. 
2 The columns of blood coming in different directions were supposed to be pressed together at this point 
(torcular, a wine-press). THE OCCIPITAL BONE 
75 
foramina are a little external and posterior to the openings of the anterior con- 
dyloid foramina, protected by a small arch of bone. At this part of the internal 
surface there is a very deep groove in which the posterior condyloid foramen, 
when it exists, has its termination. This groove is continuous, in the complete 
skull, with the transverse groove on the posterior part of the bone, and lodges 
the end of the same sinus, the lateral. In front of the foramen magnum is the 
basilar process, presenting a shallow depression, the basilar groove {clivus), which 
slopes from behind, upward and forward, and supports the medulla oblongata 
and part of the pons Varolii, and on each side of the basilar process is a narrow 
channel, which, when united with a similar channel on the petrous portion of 
the temporal bone, forms a groove {sulcus petrosus inferior) which lodges the 
inferior petrosal sinus. 
Borders. Superior Border.-The superior border, lambdoidal margin (margo 
lambdoideus), extends on each side from the superior to the lateral angle, is 
deeply serrated for articulation with the parietal bone, and forms, by this union, 
the lambdoid suture. 
Inferior Border.-The inferior border extends from the lateral to the inferior 
angle; its upper half, mastoid margin (margo mastoideus), is rough, and articu- 
lates with the mastoid portion of the temporal, forming the masto-occipital suture; 
the inferior half articulates with the petrous portion of the temporal, forming 
the petro-occipital suture; these two portions are separated from one another by 
the jugular process. In front of this process is a deep notch, which, with a 
similar one on the petrous portion of the temporal, forms the jugular foramen 
(foramen lacerum posterius). This notch is occasionally subdivided into two 
parts by a small process of bone (processus intra jugular is), and it generally 
presents an aperture at its upper part, the internal opening of the posterior 
condyloid foramen. 
Angles. Superior Angle.-The superior angle is received into the interval 
between the posterior superior angles of the two parietal bones; it corresponds 
with that part of the skull in the foetus which is called the posterior fontanelle 
(lambda). 
Inferior Angle.-The inferior angle is represented by the square-shaped surface 
of the basilar process. At an early period of life a layer of cartilage separates this 
part of the bone from the sphenoid, 
but in the adult the union between 
them is osseous. 
Lateral Angles.-The lateral an- 
gles correspond to the outer ends of 
the transverse grooves, and are re- 
ceived into the interval between the 
posterior inferior angles of the pari- 
etal and the mastoid portion of the 
temporal. The junction of the oc- 
cipital, parietal, and temporal bones 
was named the asterion by Broca. 
Structure. - The occipital bone 
consists of two compact laminae, 
called the outer and inner tables, having between them the diploic tissue; this bone 
is especially thick at the ridges, protuberances, condyles, and anterior part of the 
basilar process; while at the bottom of the fossae, especially the inferior, it is thin, 
semitransparent, and destitute of diploe. 
Development (Fig. 40).-At birth the bone consists of four distinct parts: a 
tabular squamous or expanded portion, which lies behind the foramen magnum; two 
condylic parts, which form the sides of the foramen; and a basilar part, which lies 
•4 for occipital 
' portion. 
Join about 4 yr. Join 5-6yr. 
At birth 
the 4 pieces 
separate. 
1 for each condyloid 
portion. 
Fig. 40.-Development of occipital bone. By seven centres. 
1 for basilar portion. THE SKELETON 
76 
in front of the foramen. The number of nuclei for the tabular part vary. As 
a rule, there are four, but there may be only one (Blandin) or as many as eight 
(Meckel). They appear about the eighth week of foetal life, and soon unite to 
form a single piece, which is, however, fissured in the direction indicated in 
Fig. 40. The basilar and two condyloid portions are each developed from a single 
nucleus, which appears a little later. The upper portion of the tabular surface 
-that is to say, the portion above the transverse fissure-is developed from mem- 
brane, and may remain separated from the rest of the bone throughout life, when 
it constitutes the interparietal bone, which is called the os incae, because of its fre- 
quent occurrence in Peruvian skulls. The rest of the bone is developed from 
cartilage. At about the fourth year the tabular and the two condyloid pieces 
join, and about the sixth year the bone consists of a single piece. At a later period, 
between the eighteenth and twenty-fifth years, the occipital and sphenoid become 
united, forming a single bone. 
Articulations.-With six bones: two parietal, two temporal,sphenoid,and atlas. 
Attachment of Muscles.-To twelve pairs: to the superior curved line are 
attached the Occipito-frontalis, Trapezius, and Sterno-cleido-mastoid. To the 
space between the curved lines, the Complexus,1 Splenitis capitis, and Obliquus 
capitis superior; to the inferior curved line, and the space between it and the 
foramen magnum, the Rectus capitis posticus, major and minor; to the transverse 
process, the Rectus capitis lateralis; and to the basilar process, the Rectus capitis 
anticus, major and minor, and Superior constrictor of the pharynx. 
The Parietal Bone (Os Parietale). 
The parietal bones {paries, a wall) are paired bones and form, by their union, the 
sides and roof of the cerebral cranium. Each bone is of an irregular quadrilateral 
form, and presents for examination two surfaces, four borders, and four angles. 
Surfaces. External Surface (facies parietalis).-The external surface (Fig. 41) 
is convex, smooth, and marked about its centre by an eminence called the 
parietal eminence (tuber parietale), which indicates the point where ossification 
commenced. Crossing the middle of the bone in an arched direction are two 
well-marked curved lines or ridges, the upper and lower temporal lines or ridges 
(linea temporalis superior et inferior); the former gives attachment to the tem- 
poral fascia, while the latter indicates the upper limit of the origin of the 
Temporal muscle. These lines form the temporal crest. Above these ridges 
the surface of the bone is rough and porous, and covered by the aponeurosis 
of the Occipito-frontalis; between them the bone is smoother and more polished 
than the rest; below them the bone forms part of the temporal fossa. This 
portion of bone is called the planum temporale, and affords attachment to the 
Temporal muscle. The superior stephanion is the intersection of the upper 
temporal ridge with the coronal suture. The inferior stephanion is the intersec- 
tion of the lower temporal ridge with the coronal suture. At the back part of 
the superior border, close to the sagittal suture, is a small foramen, the parietal 
foramen (foramen parietale), which transmits the emissary vein of Santorini from 
the scalp to the superior longitudinal sinus. It sometimes also transmits a 
small branch of the occipital artery. Its existence is not constant, and its 
size varies considerably. The point on the sagittal suture, between the parietal 
foramina, is the obelion. 
Internal or Cerebral Surface (facies cerebralis).-The internal surface (Fig. 42) is 
concave, presents depressions for lodging the convolutions of the cerebrum and 
numerous furrows, for the ramifications of the middle meningeal artery; the 
1 To these the Biventer cervicis should be added, if it is regarded as a separate muscle. THE PARIETAL BONE 
t. culates with opposite parietal 
A1 
77 
Articulates 
with 
frontal 
bone. 
Articulates 
with 
occipital bone. 
Squamous portion of 
temporal bone. 
Sphenoid 
Fig. 41.-Left parietal bone. External surface. 
Posterior 
superior 
angle. 
.Anterior 
superior 
angle. 
Posterior 
inferior 
angle. 
Groove for 
Mid. Melting 
Arty. 
Anterior 
inferior 
। angle. 
Fig. 42.-Left parietal bone. Internal surface. THE SKELETON 
78 
latter runs upward and backward from the anterior inferior angle and from the 
central and posterior part of the lower border of the bone. The depression for 
the middle meningeal artery at the anterior and inferior portions of the cerebral 
surface of the bone is called the sulcus arteriosus. Sometimes a distinct canal 
exists for the artery, but it never remains a canal for a long distance. Along 
the upper margin of the bone is part of a shallow groove, which, when joined 
to the opposite parietal, forms a channel for the superior longitudinal sinus (the 
sulcus sagittalis). The elevated edges of the groove afford attachment to the 
falx cerebri. Near the groove are seen several depressions, Pacchionian depressions 
[foveolae granulares [Pacchioni]). They are most frequently found in the skulls 
of old persons, and lodge the Pacchionian bodies. The internal opening of the 
parietal foramen is also seen when that aperture exists. On the inner surface of 
the posterior inferior portion of the bone is a portion of the groove for the lodge- 
ment of the lateral sinus [sulcus transversus). 
Borders. Superior Border.-The superior border, sagittal margin [margo sagit- 
talis), the longest and thickest, is dentated to articulate with its fellow of the 
opposite side, forming the sagittal suture. 
Inferior Border.-The inferior border, squamous margin [margo squamosus), is 
divided into three parts: of these, the anterior is thin and pointed, bevelled at 
the expense of the outer surface, and overlapped by the tip of the great wing 
of the sphenoid; the middle portion is arched, bevelled at the expense of the 
outer surface, and overlapped by the squamous portion of the temporal; the 
posterior portion is thick and serrated for articulation with the mastoid portion 
of the temporal. 
Anterior Border.-The anterior border, frontal margin [margo frontalis), deeply 
serrated, is bevelled at the expense of the outer surface above and of the inner 
below; it articulates with the frontal bone, forming the coronal suture. 
Posterior Border.-The posterior border, occipital margin [margo occipitalis), 
deeply denticulated, articulates with the occipital, forming the lambdoid suture. 
Angles. Anterior Superior Angle [angulus frontalis).-The anterior superior 
or frontal angle, thin and pointed, corresponds with that portion of the skull 
which in the foetus is membranous, and is called the anterior fontanelle [bregma). 
Anterior Inferior Angle [angulus sphenoidalis).-The anterior inferior or 
sphenoidal angle is thin and lengthened, being received in the interval between 
the great wing of the sphenoid and the frontal. Its inner surface is marked by a 
deep groove, sometimes a canal, for the anterior branch of the middle meningeal 
artery. At the anterior inferior angle the parietal, temporal, and frontal bones 
and the greater wing of the sphenoid bone meet. This spot is called the 
pterion. 
Posterior Superior Angle [angulus occipitalis).-The posterior superior or occip- 
ital angle corresponds with the junction of the sagittal and lambdoid sutures. In 
the fetus this part of the skull is membranous, and is called the posterior fonta- 
nelle [lambda). 
Posterior Inferior Angle [angulus mastoideus.-The posterior inferior or mas- 
toid angle articulates with the mastoid portion of the temporal bone, and 
generally presents on its inner surface a broad, shallow groove for lodging part 
of the lateral sinus. 
Development.-The parietal bone is formed in membrane, being developed 
by one centre, which corresponds with the parietal eminence, and makes its first 
appearance about the seventh or eighth week of foetal life. Ossification gradually 
extends from the centre to the circumference of the bone: the angles are conse- 
quently the parts last formed, and it is in their situation that the fontanelles exist 
previous to the completion of the growth of the bone. Occasionally the parietal 
bone is divided into two parts, upper and lower, by an antero-posterior suture. THE FRONTAL BONE 
79 
Articulations.-With five bones: the opposite parietal, the occipital, frontal, 
temporal, and sphenoid. 
Attachment of Muscles.-One only, the Temporal. 
The Frontal Bone (Os Frontale). 
The frontal bone (frons, the forehead) resembles a cockle-shell in form, and 
consists of two portions-a vertical or frontal portion, situated at the anterior 
part of the cranium, forming the forehead; and a horizontal or orbital portion, 
which enters into the formation of the roof of the orbits and nasal fossse. 
Vertical Portion of the Frontal Bone (Pars Frontalis). 
Surfaces. External Surface (facies frontalis) (Fig. 43).-In the median line, 
traversing the bone from the upper to the lower part, is occasionally seen a 
slightly elevated ridge, and in young subjects a suture, the frontal (metopic) 
suture, which represents the line of union of the two lateral halves of which the 
E^Onta! 
Eminence. 
ORBICULARIS, 
PALPEBRARUM. 
Internal 
annular process. 
External 
angular process. 
Nasal spine. 
Fig. 43.-Frontal bone. Outer surface. 
bone consists at an early period of life; in the adult this suture is usually oblit- 
erated and the bone forms one piece; traces of the obliterated suture are, how- 
ever, generally perceptible at the lower part. On either side of this ridge, a little 
below the centre of the bone, is a rounded eminence, the frontal eminence (tuber 
frontale). These eminences vary in size in different individuals, and are occa- 
sionally unsymmetrical in the same subject. They are especially prominent in 
cases of well-marked cerebral development. The whole surface of the bone 
above this part is smooth, and covered by the aponeurosis of the Occipito- 
frontalis muscle. Below the frontal eminence and separated from it by a slight 80 
THE SKELETON 
groove is the superciliary ridge (arcus s uper ciliar is), broad internally, where it 
is continuous with the nasal eminence, but less distinct as it arches outward. 
These ridges are caused by the projection outward of the frontal air sinuses,1 
and give attachment to the Orbicularis palpebrarum and Corrugator supercilii. 
Between the two superciliary ridges is a smooth, flat surface, the glabella. 
Nearly corresponding with the glabella is the ophryon, a point in the mid-line 
on a level with the upper border of the eyebrows, which is the centre of the 
narrowest transverse diameter of the forehead. Beneath the superciliary ridge 
is the orbital margin or supraorbital arch (margo supraorb italis), a curved and 
prominent margin, which forms the upper boundary of the orbit and separates 
the vertical from the horizontal portion of the bone. The outer part of the 
arch is sharp and prominent, affording to the eye, in that situation, considerable 
protection from injury; the inner part is less prominent. At the junction of the 
internal and middle third of this arch is a notch, sometimes converted into a 
foramen, and called the supraorbital notch or foramen (incisura supraorbitalis or 
foramen supraorbitale). It transmits the supraorbital artery, vein, and nerve. A 
small aperture is seen in the upper part of the notch, which transmits a vein 
from the diploe to join the supraorbital vein. To the median side of the 
supraorbital notch there is often a notch (incisura frontalis) for the passage 
of the frontal artery and frontal nerve. The supraorbital arch terminates 
externally in the external angular process (processus zygomaticus) and internally 
in the internal angular process. The external angular process is strong, prominent, 
and articulates with the malar bone; running upward and backward from it are 
two well-marked lines, which, commencing together from the external angular 
process as the temporal ridge, crest or line (linea temporalis), soon diverge from 
each other and run in a curved direction across the bone. These are the 
upper and lower temporal ridges; the upper gives attachment to the temporal 
fascia, the lower to the Temporal muscle. Beneath them is a slight concavity 
that forms the anterior part of the temporal fossa and gives origin to the 
Temporal muscle. The internal angular processes are less marked than the 
external, and articulate with the lachrymal bones. Between the internal angular 
processes is a rough, uneven interval, the nasal notch, which articulates in the 
middle line with the nasal bone, and on either side with the nasal process of the 
superior maxillary bone. From the concavity of this notch projects a process, 
the nasal process, which extends beneath the nasal bones and nasal processes of 
the superior maxillary bones and supports the bridge of the nose. On the under 
surface of this is a long, pointed process, the nasal or frontal spine (spina nasalis 
or frontalis), and on either side a small grooved surface enters into the formation 
of the roof of the nasal fossa. The nasal spine forms part of the septum of the 
nose, articulating in front with the nasal bones and behind with the perpen- 
dicular plate of the ethmoid. The junction of the nasal and frontal bones is 
called the nasion. 
Internal Surface (cerebral surface, facies cerebralis) (Fig. 44).-Along the middle 
line is a vertical groove, the sulcus sagittalis, the edges of which unite below to 
form a ridge, the frontal crest (crista frontalis); the groove lodges the superior 
longitudinal sinus, whilst its margins afford attachment to the falx cerebri. The 
crest terminates below at a small notch which is converted into a foramen by 
articulation with the ethmoid. It is called the foramen caecum, and varies in 
size in different subjects: it is sometimes partially or completely impervious, 
1 Some confusion is occasioned to students commencing the study of anatomy by the name " sinuses " having 
been given to two perfectly different kinds of spaces connected with the skull. It may be as well, therefore, to 
state here at the outset, that the " sinuses" in the interior of the cranium which produce the grooves on the 
inner surface of the bones are venous channels along which the blood runs in its passage back from the brain, 
while the " sinuses " external to the cranial cavity (the frontal sphenoidal, ethmoidal, and maxillary) are hollow 
spaces in the bones themselves which communicate with the nostrils, and contain air. THE FRONTAL BONE 
81 
lodges a process of the falx cerebri, and when open transmits a vein from the 
lining membrane of the nose to the superior longitudinal sinus. On either 
side of the groove the bone is deeply concave, presenting depressions for the 
convolutions of the brain, and numerous small furrows for lodging the rami- 
With superior maxillary. 
Frontal sinus. 
With perpendicular plate of ethmoid. 
With nasal.' 
\Under surface of nasal process, 
forming part of roof of nose. 
Fig. 44.-Frontal bone. Inner surface. 
fications of the anterior branches of the middle meningeal arteries. Several 
small irregular fossse are seen also on either side of the groove, for the reception 
of the Pacchionian bodies. 
Border.-The border of the vertical portion is thick, strongly serrated, bevelled 
at the expense of the internal table above, where it rests upon the parietal bones, 
and at the expense of the external table at each side, where it receives the lateral 
pressure of those bones; this border is continued below into a triangular rough 
surface which articulates with the great wing of the sphenoid. 
Structure.-The vertical portion and external angular processes are very thick, 
consisting of diploic tissue contained between two compact laminae. 
Horizontal or Orbital Portion of the Frontal Bone (Pars Orbitalis). 
This portion of the bone consists of two thin plates, the orbital plates, which 
form the vault of the orbit, separated from one another by a median gap, the 
ethmoidal notch. 
Surfaces. External Surface.-The inferior or external surface of each orbital 
plate (facies orbitalis) consists of a smooth, concave, triangular lamina of bone, 
marked at its anterior and external part (immediately beneath the external 
angular process) by a shallow depression, the lachrymal fossa (fossa glandule? 
lacrimalis) for lodging the lachrymal gland; and at its anterior and internal part THE SKELETON 
82 
by a depression (sometimes a small tubercle), the trochlear fossa (fovea trochlearis), 
for the attachment of the cartilaginous pulley of the Superior oblique muscle of 
the eye. The ethmoidal notch (incisura ethmoidalis) separates the two orbital 
plates; it is quadrilateral, and filled up, when the bones are united, by the cribri- 
form plate of the ethmoid. The margins of this notch present several half-cells, 
which, when united with corresponding half-cells on the upper surface of the eth- 
moid, complete the ethmoidal cells; two grooves are also seen crossing these edges 
transversely; they are converted into canals by articulation with the ethmoid, and 
are called the anterior and posterior ethmoidal foramina or canals (foramen ethmoi- 
dale anterius and foramen ethmoidale posterius) : they open on the inner wall of the 
orbit. The anterior one transmits the nasal nerve and anterior ethmoidal vessels, 
the posterior one the posterior ethmoidal vessels. In front of the ethmoidal 
notch, on each side of the nasal spine, is the opening of the frontal air sinus (sinus 
frontalis). These are two irregular cavities, which extend upward and outward, a 
variable distance, between the two tables of the skull, and are separated from one 
another by a thin, bony septum (septum sinuum frontalium), which is often dis- 
placed to one side. Within the sinuses imperfect trabeculae of bone often exist. The 
sinuses are beneath and give rise to the prominences above the supraorbital arches 
called the superciliary ridges (arcus superciliares). The frontal air sinuses are absent 
at birth, become apparent about the seventh year of life, and from this period until 
the age of twenty increase gradually in size. Sometimes, however, the sinuses 
remain very small or never develop at all-or one side may be large and the other 
small-or one may exist on one side and be absent on the other.1 'The right sinus 
is usually the larger. These cavities are larger in men than in women. The floor 
of each sinus is very thin and is over the orbit and the upper border of the lateral 
mass of the ethmoid. The thinnest portion of the floor is at the upper and 
inner angle of the orbit, and at this point pus is apt to point in cases of 
empyema of the sinus. The frontal sinuses are lined by mucous membrane 
and each sinus communicates with the middle meatus of the nose by the infun- 
dibulum and part of the semilunar hiatus. In some cases the sinuses commu- 
nicate with each other by means of an aperture in the septum and occasionally 
join the sinus in the crista galli of the ethmoid.2 
Internal Surface (cerebral surface, facies cerebralis).-1The internal surface of 
the horizontal portion presents the convex upper surfaces of the orbital plates, 
separated from each other in the mid- 
dle line by the ethmoidal notch, and 
marked by eminences and depressions for 
the convolutions of the frontal lobes of 
the brain. 
Border.-The border of the horizontal 
portion is thin, serrated, and articulates 
with the lesser wing of the sphenoid. 
Structure.-The horizontal portion is 
thin, translucent, and composed entirely 
of compact tissue; hence the facility with 
which instruments can penetrate the 
cranium through this part of the orbit. 
Development (Fig. 45).-The frontal 
bone is formed in membrane, being 
developed by two centres, one for each lateral half, which make their appearance 
about the seventh or eighth week, above the orbital arches. From this point 
ossification extends, in a radiating manner, upward into the forehead and back- 
Fig. 45.-Frontal bone at birth. Developed by 
two lateral halves. 
1 Dr. D. Kerfoot Shute. Article on the Skull, in Reference Handbook of the Medical Sciences. 2 Ibid. THE TEMPORAL BONE 
83 
ward over the orbit. At birth the bone consists of two pieces, which afterward 
become united, along the middle line, by a suture which runs from the vertex 
to the root of the nose. This suture usually becomes obliterated within a few 
years after birth; but it occasionally remains throughout life, constituting the 
metopic suture. Secondary centres of ossification appear for the nasal spine- 
one on either side of the internal angular process where it articulates with the 
lachrymal bone; and sometimes there is one on either side at the lower end of 
the coronal suture. This latter centre sometimes remains ununited, and is 
known as the pterion ossicle, or it may join with the parietal, sphenoid, or tem- 
poral bone. 
Articulations.-With twelve bones: two parietal, the sphenoid, the ethmoid, 
two nasal, two superior maxillary, two lachrymal, and two malar. 
Attachment of Muscles.-To three pairs: the Corrugator supercilii, Orbicu- 
laris palpebrarum, and Temporal, on each side. 
The Temporal Bone (Os Temporale). 
The temporal ones (tempus, time) are paired bones, situated at the sides and 
base of the skull. Each presents for examination a squamous, mastoid, and petrous 
portion. 
The squamous portion (squama, a scale), the anterior and upper part of the 
bone, is scale-like in form, and thin and translucent in texture (Fig. 46). 
Squamous Portion of the Temporal Bone (Squama Temporalis). 
SQUAMOUS SUTURE 
TEMPORAL FASCIA 
SPHENOIDAL MARGIN 
SULCUS FOR MIDDLE 
TEMPORAL ARTERY' 
REMAINS OF 
SQUAMOSO- 
MASTOID' 
SUTURE I 
MASTOID 
fossa' 
SUPRA- 
MEATAL' 
SPINE 
\APEX OF PETROUS 
PORTION 
MASTOID 
FORAMEN 
VAGINAL PORTION 
OF STYLOID 
^PETROTYMPANIC OR 
GLASERIAN FISSURE 
MASTOI D 
PORTION 
EXTERNAL AUDITORY MEATUS TYMPANIC PORTION 
Surfaces. Outer Surface (facies temporalis).-Its outer surface is smooth, convex, 
and grooved at its back part for the middle or deep temporal artery {sulcus a. 
temporalis mediae)-, it affords attachment to the Temporal muscle and forms part 
of the temporal fossa. At its back part may be seen a curved ridge-part of the 
temporal ridge or line; it serves for the attachment of the temporal fascia and 
Fig. 46.-Right temporal bone, from without. (Spalteholz.) THE SKELETON 
84 
limits the origin of the Temporal muscle. The boundary between the squamous 
and mastoid portions of the bone, as indicated by traces of the original suture, 
lies fully half an inch below this ridge. Projecting from the lower part of the 
squamous portion is a long, arched process of bone, the zygoma or zygomatic 
process {processus zygomaticus). This process is at first directed outward, its 
two surfaces looking upward and downward; it then appears as if twisted 
upon itself, and runs forward, its surfaces now looking inward and outward. 
The superior border of the process is long, thin, and sharp, and serves for the 
attachment of the temporal fascia. The inferior, short, thick, and arched, has 
attached to it some fibres of the Masseter muscle. Its outer surface is convex 
and subcutaneous; its inner is concave, and also affords attachment to the 
Masseter. The extremity, broad and deeply serrated, articulates with the malar 
bone. The zygomatic process is connected to the temporal bone by three divi- 
sions, called its roots-an anterior, middle, and posterior. The anterior, which 
is short, but broad and strong, is directed inward, to terminate in a rounded 
eminence, the eminentia articularis or articular eminence (tuberculum articulare) 
(Fig. 46). This eminence forms the front boundary of the glenoid or mandibular 
fossa (fossa mandibular is), and in the recent state is covered with cartilage. 
The middle root is known as the post-glenoid process or tubercle, and is very 
prominent in young bones. It separates the mandibular portion of the glenoid 
fossa from the external auditory meatus, and terminates at the commencement 
of a well-marked fissure, the Glaserian (petro-tympanic) fissure (fissura petro- 
tympanica [Glaseri]). The posterior root, which is strongly marked, runs from 
the upper border of the zygoma backward over the external auditory meatus. 
It is termed the supramastoid or temporal crest, and forms part of the lower 
temporal ridge. At the junction of the anterior root with the zygoma is a 
projection, called the tubercle, for the attachment of the external lateral liga- 
ment of the lower jaw; and between the anterior and middle roots is an oval 
depression, forming part of the glenoid (mandibular) fossa (pWpry, a socket), for 
the reception of the condyle of the lower jaw. This fossa is bounded, in front, 
by the eminentia articularis; behind, by the tympanic plate, which separates it 
from the external auditory meatus; it is divided into two parts by a narrow slit, 
the Glaserian or petro-tympanic fissure. The anterior or mandibular part, formed 
by the squamous portion of the bone, is smooth, covered in the recent state with 
cartilage, and articulates with the condyle of the lower jaw. This part of the 
glenoid fossa presents posteriorly a small conical eminence, the post-glenoid 
process, already referred to. This process is the representative of a prominent 
tubercle which, in some of the mammalia, descends behind the condyle of the 
jaw, and prevents it being displaced backward during mastication (Humphry). 
The posterior part of the glenoid fossa, which lodges a portion of the parotid 
gland, is formed chiefly by the tympanic plate, which constitutes the anterior 
wall of the tympanum and external auditory meatus. The plate of bone termi- 
nates above in the Glaserian fissure, and below forms a sharp edge, the vaginal 
process of the styloid (vagina processus styloidei), which gives origin to sortie of 
the fibres of the Tensor palati muscle. The Glaserian fissure, which leads into 
the tympanum, lodges the processus gracilis of the malleus, and transmits the 
tympanic branch of the internal maxillary artery. The chorda tympani nerve 
passes through a separate canal, parallel to the Glaserian fissure, the canal of 
Huguier (canaliculus chordcc tympani), on the outer side of the Eustachian 
tube, in the retiring angle between the squamous and petrous portions of the 
temporal bone.1 Between the posterior bony wall of the external auditory meatus 
1 This small fissure must not be confounded with the large canal which lies above the Eustachian tube and 
transmits the Tensor tympani muscle. THE TEMPORAL BONE 
85 
and the posterior root of the zygoma is the area called the suprameatal triangle of 
Prof. Macewen. Through this space the surgeon pushes the gauge in order to 
carry it into the antrum of the mastoid process. 
Internal Surface (cerebral surface, jacies cerebralis).-rlL\\e internal surface of 
the squamous portion (Fig. 47) is concave, presents numerous eminences and 
depressions for the convolutions of the cerebrum, and two well-marked grooves 
for the branches of the middle meningeal artery. 
Aqueeductus vestibuli. 
Eminence for superior semicircular canal. 
Hiatus Fallopii. 
Depression for dura mater. 
Meatus auditorius internus. 
Opening for smaller petrosal nerve. 
Depression for Gasserian Ganglion. 
Bristle passed through carotid canal. 
Fig. 47.-Left temporal bone. Inner surface. 
Borders. Superior Border.-The superior border, parietal margin (margo 
parietalis), is thin, bevelled at the expense of the internal surface, so as to 
overlap the lower border of the parietal bone, forming the squamous suture. 
Anterior Inferior Border.-The anterior inferior border, sphenoidal margin (margo 
sphenoidalis), is thick, serrated, and bevelled, alternately at the expense of the 
inner and outer surfaces, for articulation with the great wing of the sphenoid. 
Posterior Inferior Border.-The posterior inferior border, occipital margin 
(margo occipitalis'), is serrated and articulates with the occipital bone. 
The Mastoid Portion of the Temporal Bone (Pars Mastoidea). 
The mastoid portion (paaroq, a nipple or teat) is situated at the posterior part 
of the bone (Figs. 46, 48, and 49). 
Surfaces. Outer Surface.-The outer surface of the mastoid is rough, and 
gives attachment to the Occipito-frontalis and Retrahens aurem muscles. It 
is perforated by numerous foramina; one of these, of large size, situated at the 
posterior border of the bone, is termed the mastoid foramen (j or amen mastoideum); 
it transmits a vein to the lateral sinus and a small artery from the occipital to 
supply the dura mater. The position and size of this foramen are very variable. 
It is not always present; sometimes it is situated in the occipital bone or in the 
suture between the temporal and the occipital. The mastoid portion is con- 86 
THE SKELETON 
tinned below into a conical projection, the mastoid process (processus mastoideus), 
the size and form of which vary somewhat. The mastoid process begins to 
develop during the second year and does not attain full size until after puberty. 
This process serves for the attachment of the Sterno-mastoid, Splenius capitis, 
and Trachelo-mastoid muscles. On the inner side of the mastoid process is a 
deep groove, the digastric fossa (incisura mastoidea), for the attachment of the 
Digastric muscle; and, running parallel with it, but more internal, the occipital 
groove (sulcus a. occipitalis), which lodges the occipital artery. The suprameatal 
triangle of Prof. Macewen is bounded by the posterior root of the zygoma, the 
posterior bony wall of the external auditory meatus, and an imaginary line join- 
ing these two. Through this triangle the surgeon enters his instrument in order 
to reach the mastoid antrum. Behind the suprameatal spine is a depression 
known as the mastoid fossa (fossa mastoidea), which contains numerous small 
openings for bloodvessels. 
Canal for tensor tympan 
Aqueductus Fallopii* 
Opening into antrum. 
Processus, 
cochleariformis. 
Eustachian tube 
Promontory. 
Stapes. 
Antrum. 
Malleus. 
.Incus. 
Tensor tympani. 
■Proc, cochleariformis. 
Eustachian tribe. 
'Carotid canal. 
Carotid canal. 
Fenestra rotunda. 
■Styloid process. 
Pyramid. 
' Aqueductus Fallopii. 
Fig. 48.-Section through the petrous and mastoid portions of the temporal bone, showing the communication 
of the cavity of the tympanum with the mastoid antrum. 
'Marrow cells. 
Internal Surface.-The internal surface of the mastoid portion presents a deep, 
curved groove, the sigmoid fossa or sulcus (sulcus sigmoideus), which lodges part 
of the lateral sinus; and into it may be seen opening the mastoid foramen, 
which transmits an emissary vein from the lateral sinus to the posterior auricular 
or occipital vein and a small artery, the mastoid branch of the occipital artery 
(ramus mastoideus). The groove for the lateral sinus is separated from the inner- 
most of the mastoid air-cells by only a thin lamina of bone, and even this may be 
partly deficient. A section of the mastoid process (Figs. 48 and 49) shows it to be 
hollowed out into a number of cellular spaces, communicating with each other, 
called the mastoid cells (cellules mastoideoe), which exhibit the greatest possible 
variety as to their size and number, and which do not exist at birth, but develop 
with the growth of the mastoid process. At the upper and front part of the 
bone these cells are large and irregular, and contain air. They diminish in size 
toward the lower part of the bone, those situated at the apex of the mastoid 
process being quite small and usually containing marrow. These pneumatic 
cells extend far beyond the mastoid. Some may reach the floor of the Eustachian THE TEMPORAL BONE 
87 
canal; others the jugular portion of the occipital bone; others the roof of the 
external auditory canal, and some pass up toward the squamous portion? Occa- 
sionally they are entirely absent, and the mastoid is solid throughout. In addi- 
tion to these pneumatic cells may be seen a large, irregular cavity (Figs. 48 and 
49), situated at the upper and front part of the section. It is called the mastoid or 
tympanic antrum (antrum tympanicum), and must be distinguished from the mas- 
toid cells, though it communicates with them. The mastoid cells are not developed 
until after puberty, but the mastoid antrum is almost as large at birth as it is in 
the adult. 
It is filled with air, and is lined with a prolongation of the mucous membrane 
of the tympanum, which extends into it through an opening, by which it com- 
municates with the cavity of the tympanum. The mastoid antrum is bounded 
above by a thin plate of bone, the tegmen tympani, which separates it from the 
middle fossa of the base of the skull on the anterior surface of the petrous portion 
PROMINENCE OVER 
SEMICIRCULAR CANAL 
FENESTRA OVALIS 
OR VESTIBULI 
TEGMEN 
TYM PANI 
AQUEDUCT OF 
FALLOPIUS 
PROCESSUS 
COCH LEAR I FO R M IS 
SEPTUM OF 
EUSTACHIAN TUBE 
PROBE IN 
TYMPANIC 
CANAL 
EMINENTIA 
PYRAMIDALIS 
SEMICANAL FOR 
TENSOR TYMPANI 
FENESTRA ROTUNDA 
OR COCHLEA 
promontoryI 
PROBE IN 
TYMPANIC CANAL 
^MASTOID 
CELLS 
Fig. 49.-Right temporal bone cut open. Lateral view of medial half of bone. X 2. (Spalteholz.) 
of the temporal bone; below by the mastoid process; externally by the squamous 
portion of the bone just below the supramastoid crest; and internally by the 
external semicircular canal of the internal ear, which projects into its cavity. 
The opening by which it communicates with the tympanum is situated at the 
superior internal angle of the posterior wall of that cavity; it is a triangular 
opening into that portion of the tympanic cavity which is known as the tympanic 
attic or epitympanic recess or space (aditus ad antrum)-that is to say, that 
portion of the tympanum which is above the level of the membrana tympani. 
In consequence of the communication which exists between the tympanum and mastoid cells, 
inflammation of the lining membrane of the former cavity may easily travel backward to that 
of the antrum, leading to caries and necrosis of their walls and the risk of transference of the 
inflammation to the lateral sinus or encephalon. 
1 Dr. D. Kerfoot Shute, in Reference Handbook of the Medical Sciences. 88 
THE SKELETON 
Borders. Superior Border.-The superior border of the mastoid portion is 
broad and rough, its serrated edge sloping outward, for articulation with the 
posterior inferior angle of the parietal bone. 
Posterior Border.-The posterior border, also, uneven and serrated, articu- 
lates with the inferior border of the occipital bone between its lateral angle and 
jugular process. 
The Petrous Portion of the Temporal Bone (Pars Petrosa [Pyramis]) (Fig. 47). 
The petrous portion (xerpot;, a stone), so named from its extreme density and 
hardness, is a pyramidal process of bone wedged in at the base of the skull 
between the sphenoid and occipital bones. Its direction from without is inward, 
forward, and a little downward. It presents for examination a base, an apex, 
three surfaces, and three borders, and contains, in its interior, the essential parts 
of the organ of hearing. 
Base.-The base is applied against the internal surface of the squamous and 
mastoid portions, its upper half being concealed; but its lower half is exposed 
by the divergence of those two portions of the bone, which brings into view the 
oval, expanded orifice of a canal leading into the tympanum, the meatus audi- 
torius externus (meatus acusticus externus). The curved tympanic plate or part 
(pars tympanica) forms the anterior wall, the floor, and a part of the posterior 
wall of this meatus, while the squamous portion of the temporal completes it 
above and behind. The entrance to the meatus is bounded throughout the 
greater part of its circumference by the auditory process, which is the name 
applied to the free rough margin of the tympanic plate, and which gives attach- 
ment to the cartilaginous portion of the meatus. Superiorly the entrance to 
the meatus is limited by the posterior root of the zygoma. At the upper and 
posterior portion of the bony meatus is a spine of bone known as the suprameatal 
spine or spine of Henle (spina suprameatum), which is a valuable surgical land- 
mark. In most skulls it is distinctly marked. 
Apex (apex pyramidis).-The apex of the petrous portion, rough and uneven, 
is received into the angular interval between the posterior border of the greater 
wing of the sphenoid and the basilar process of the occipital; it presents the anterior 
or internal orifice of the carotid canal (foramen caroticum internum), and forms 
the posterior and external boundary of the foramen lacerum medium. 
Surfaces. Anterior Surface (facies anterior pyramidis).-The anterior surface 
of the petrous portion (Fig. 47) forms the posterior part of the middle fossa of 
the skull. This surface is continuous with the squamous portion, to which it is 
united by a suture, the petro-squamous suture, the remains of which are distinct even 
at a late period of life. It presents six points for examination: (1) An eminence 
(eminentia arcuata) near the centre, which indicates the situation of the 
superior semicircular canal. (2) In front and a little to the outer side of this 
eminence a depression indicating the position of the tympanum; here the layer 
of bone which separates the tympanum from the cranial cavity is extremely thin, 
and is known as the tegmen tympani. (3) A shallow groove, sometimes double, 
leading outward and backward to an oblique opening, the hiatus Fallopii (hiatus 
canalis facialis), for the passage of the greater petrosal nerve and the petrosal 
branch of the middle meningeal artery. (4) A smaller opening (apertura superior 
canalicidi tympanici), occasionally seen external to the latter, for the passage of 
the smaller petrosal nerve. (5) Near the apex of the bone, the termination of the 
carotid canal, the internal carotid foramen (foramen caroticum internum), the wall 
of which in this situation is deficient in front. (6) Above the canal a shallow 
depression, the trigeminal depression (impressio trigemini), for the reception of the 
Gasserian ganglion. THE TEMPORAL BONE 
89 
Posterior Surface (facies posterior pyramidis).-The posterior surface forms the 
front part of the posterior fossa of the skull, and is continuous with the inner 
surface of the mastoid portion of the bone. It presents three points for exami- 
nation: 1. About its centre, a large orifice, the meatus auditorius internus (meatus 
acusticus internus), whose size varies considerably; its margins are smooth and 
rounded, and it leads into a short canal, about four lines in length, which runs 
directly outward and is closed by a vertical plate, the lamina cribrosa, which is 
divided by a horizontal crest, the falciform crest (crista falciformis), into two unequal 
portions (Fig. 50). Each portion is subdivided by a little vertical crest into two parts, 
named, respectively, anterior and posterior. The lower portion presents three sets 
of foramina: one group just below the poste- 
rior part of the crest, the area cribrosa media, 
consisting of a number of small openings 
for the nerves to the saccule; below and 
posterior to this, the foramen singulars, or 
opening for the nerve to the posterior semi- 
circular canal; in front and below the first, 
the tractus spiralis foraminosus, consisting 
of a number of small, spirally arranged 
openings which terminate in the canalis 
centralis cochleae and transmit the nerve to 
the cochlea; the upper portion, that above 
the crista, presents behind a series of small 
openings the area cribrosa superior, for the 
passage of filaments to the utricle and supe- 
rior and external semicircular canal, and, in 
front, one large opening, the commence- 
ment of the aquaeductus Fallopii (canalis 
facialis), for the passage of the facial nerve. 
2. Behind the meatus auditorius, a small 
slit (apertura externa aquaeductus vestibuli), 
almost hidden by a thin plate of bone, lead- 
ing to a canal, the aquaeductus vestibuli, 
which transmits the ductus endolymphaticus 
together with a small artery and vein. In 
the interval between these two openings, but above them, is an angular depression 
(fossa suharcuata) which lodges a process of the dura mater, and transmits a 
small vein into the cancellous tissue of the bone. In the child this depression 
is represented by a large fossa, the floccular fossa, which extends backward as a 
blind tunnel under the superior semicircular canal. 
Inferior Surface (facies inferior pyramidis).-The inferior or basilar surface (Fig. 
51) is rough and irregular, and forms part of the base of the skull. Passing from 
the apex to the base, this surface presents eleven points for examination: 1. A 
rough surface, quadrilateral in form, which serves partly for the attachment of 
the Levator palati and Tensor tympani muscles. 2. The large, circular aperture 
of the carotid canal, the external carotid foramen (foramen caroticum externum); the 
canal ascends at first vertically, and then, making a bend, runs horizontally for- 
ward and inward; it transmits the internal carotid artery and the carotid plexus. 
Within the carotid canal are several openings (canaliculi carotico tympanici) which 
transmit tympanic branches of the internal carotid artery and of the carotid plexus. 
3. The opening of the aquaeductus cochleae (apertura externa canaliculi cochleae), a 
small triangular opening, lying on the inner side of the latter, close to the posterior 
border of the petrous portion; it transmits a vein from the cochlea, which joins 
the internal jugular. 4. Behind these openings a deep depression, the jugular fossa 
Fig. 50.-Diagrammatic view of the fundus 
of the internal auditory meatus: 1. Falciform 
crest. 2. Anterior superior cribriform area. 2'. 
Internal opening of the aquaeductus Fallopii. 
3. Vertical crest which separates the anterior 
and posterior superior cribriform areas. 4. Pos- 
terior superior cribriform area, with (4') open- 
ings for nerve-filaments. 5. Anterior inferior 
cribriform area. 5'. Spirally arranged, sieve-like 
openings for the nerves to the cochlea. 5". Open- 
ing of the central canal of the cochlea. 6. Crest 
which separates the anterior and posterior infe- 
rior cribriform areas. 7. Posterior inferior crib- 
riform area. 7'. Orifices for the branches of the 
nerve to the saccule. 8. Foramen singulare of 
Morgagni, with the anterior portion of the canal 
which gives passage to the nerve to the posterior 
semicircular canal. (Testut) THE SKELETON 
90 
(fossa jugularis), which varies in depth and size in different skulls; it lodges the 
lateral sinus, and, with a similar depression on the margin of the jugular process of 
the occipital bone, forms the foramen lacerum posterius or jugular foramen. 5. A 
foramen which is the opening of a small canal {canaliculus tympanicus), for the 
Canals for Eustachian tube and 
TENSOR TYMPANI MUSCLE. 
LEVATOR PALATI. 
tensor' 
iTYMPANI 
Rough quadrilateral surface. 
Opening of carotid canal. 
Canal for Jacobson's nerve. 
Aquseductus cochlese. 
Canal for Arnold's nerve. 
STYLO-PHARYNQEU8. 
Vaginal process. 
Jugular fossa.- 
Styloid process. 
Stylo-mastoid foramen.' 
Jugular surface.' 
Auricular fissure.. 
Fig. 51.-Petrous portion. Inferior surface. 
passage of Jacobson's nerve (the tympanic branch of the glosso-pharyngeal); 
this foramen is seen in front of the bony ridge dividing the carotid canal from 
the jugular fossa. 6. A small foramen on the wall of the jugular fossa, for the 
entrance of the auricular branch of the pneumogastric {Arnold's) nerve. 7. Behind 
the jugular fossa a smooth, square-shaped facet, the jugular surface; it is covered 
with cartilage in the recent state, and articulates with the jugular process of 
the occipital bone. 8. The vaginal process {vagina processus siyloidea), a very 
broad, sheath-like plate of bone, which extends backward from the carotid canal 
and gives attachment to part of the Tensor palati muscle; this plate divides 
behind into two laminae, the outer of which is continuous with the tympanic 
plate, the inner with the jugular process. 9. Between these laminae is the ninth 
point for examination, the styloid process {processus styloideus), a sharp spine, 
about an inch in length; it is directed downward, forward, and inward, varies 
in size and shape, and sometimes consists of several pieces united by cartilage; it 
affords attachment to three muscles, the Stylo-pharyngeus, Stylo-hyoideus, and 
Stylo-glossus, and two ligaments, the stylo-hyoid and stylo-maxillary. 10. The 
stylo-mastoid foramen {foramen stylomastoideum), a rather large orifice, placed 
between the styloid and mastoid processes; it is the termination of the aquaeductus 
Fallopii, and transmits the facial nerve and stylo-mastoid artery. 11. The auricular 
fissure {fosura tympanomastoidea), situated between the tympanic plate and 
mastoid processes, for the exit of the auricular branch of the pneumogastric nerve THE TEMPORAL BONE 
91 
(Arnold's nerve). This fissure is the external opening of the canaliculus mas- 
toideus, which passes to the aqueduct of Fallopius. 
Borders. Superior Border (angulus superior pyramidis).-The superior, the 
longest, is grooved for the superior petrosal sinus, and has attached to it the ten- 
torium cerebelli; at its inner extremity is a semilunar notch, upon which the fifth 
nerve lies. 
Posterior Border (angulus posterior pyramidis).-The posterior border is inter- 
mediate in length between the superior and the anterior. Its inner half is marked 
by a groove, which, when completed by its articulation with the occipital, forms 
the channel for the inferior petrosal sinus. Its outer half presents a deep excava- 
tion, the jugular fossa (fossa jugularis), which, with a similar notch on the occipital, 
forms the foramen lacerum posterius. A projecting eminence of bone occasionally 
stands out from the centre of the notch, and divides the foramen into two parts. 
Anterior Border (angulus anterior pyramidis).-The anterior border is divided 
into two parts-an outer, joined to the squamous portion by a suture, the remains 
of which are distinct; an inner, free, articulating with the spinous process of the 
sphenoid. At the angle of junction of the petrous and squamous portions is 
seen the opening of the canalis musculotubarius. This canal is completely or 
partially divided into two canals, separated from one another by a thin plate of 
bone, the processus cochleariformis (septum canalis musculotubarii); they both lead 
into the tympanum, the upper one (semicanalis m. tensoris tympani) transmitting 
the Tensor tympani muscle, the lower 
one (semicanalis tuboe auditivoe) form- 
ing the bony part of the Eustachian 
tube or canal. 
Structure.-The squamous portion 
is like that of the other cranial bones: 
the mastoid portion, cellular; and the 
petrous portion, dense and hard. 
Development (Fig. 52).-The tem- 
poral bone is developed by ten centres, 
exclusive of those for the internal ear 
and the ossicula - viz., one of the 
squamous portion including the zygo- 
ma, one for the tympanic plate, six for 
the petrous and mastoid parts, and two 
for the styloid process. Just before the 
close of foetal life the temporal bone 
consists of four parts: 1. The squamo- 
zygomatic part, ossified in membrane 
from a single nucleus, which appears 
at its lower part about the second 
month. 2. The tympanic plate, an imperfect ring, in the concavity of which is 
a groove, the sulcus tympanicus, for the attachment of the circumference of the 
tympanic membrane. This is also ossified from a single centre, which appears 
about the third month. 3. The petro-mastoid part is developed from six cen- 
tres, which appear about the fifth or sixth month. Four of these are for the 
petrous portion, and are placed around the labyrinth, and two for the mastoid 
(Vrolik). According to Huxley, the centres are more numerous, and are dis- 
posed so as to form three portions: (1) including most of the labyrinth, with a 
part of the petrous and mastoid, he has named prootic; (2) the rest of the petrous, 
the opisthotic; and (3) the remainder of the mastoid, the epiotic. The petro- 
mastoid is ossified in cartilage. 4. The styloid process is also ossified in cartilage 
from two centres: one for the base, which appears before birth, and is termed the 
1 for 
squamous 
portion, 
including' 
zygoma: 
2d month. 
Unite about 
time of birth. 
At birth 3 pieces separate ; 
unite during 1st year. 
1 for tympanic 
plate. 
6 for petrous 
and mastoid 
portions. 
2 for styloid process. 
Fig. 52.-Development of the temporal bone. By 
ten centres. 92 
THE SKELETON 
tympanohyal; the other, comprising the rest of the process, is named the stylohyal, 
and does not appear until after birth. Shortly before birth the tympanic plate joins 
with the squamous. The petrous and mastoid join with the squamous during 
the first year, and the tympanohyal portion of the styloid process about the same 
time. The stylohyal does not join the rest of the bone until after puberty, and 
in some skulls never becomes united. The subsequent changes in this bone are, 
that the tympanic plate extends outward and backward, so as to form the meatus 
auditorius. The extension of the tympanic plate, however, does not take place at 
an equal rate all around the circumference of the ring, but occurs most rapidly 
on its anterior and posterior portions, and these outgrowths meet and blend, and 
thus, for a time, there exists in the floor of the meatus a foramen, the foramen of 
Huschke; this foramen may persist throughout life. The glenoid cavity is at first 
extremely shallow, and looks outward as well as downward; it becomes deeper 
and is ultimately directed downward. Its change in direction is accounted for 
as follows: the part of the squamous temporal which supports it lies at first below 
the level of the zygoma. As, however, the base of the skull increases in width, 
this lower part of the squama is directed horizontally inward to contribute to 
the middle fossa of the skull, and its surfaces therefore come to look upward and 
downward. The mastoid portion is at first quite flat, and the stylo-mastoid fora- 
men and rudimentary styloid process lie immediately behind the entrance to the 
auditory meatus. With the development of the air-cells the outer part of the 
mastoid portion grows downward and forward to form the mastoid process, and 
the styloid process and stylo-mastoid foramen now come to lie on the under sur- 
face. The descent of the foramen is necessarily accompanied by a corresponding 
lengthening of the aqueduct of Fallopius. 
The downward and forward growth of the mastoid process also pushes forward 
the tympanic plate, so that the portion of it which formed the original floor of 
the meatus and containing the foramen of Huschke is ultimately found in the 
anterior wall. With the gradual increase in size of the petrous portion the floc- 
cular fossa or tunnel under the superior semicircular canal becomes filled up 
and almost obliterated. 
Articulations.-With five bones-occipital, parietal, sphenoid, inferior maxil- 
lary, and malar. 
Attachment of Muscles.-To fifteen : to the squamous portion, the Tem- 
poral; to the zygoma, the Masseter; to the mastoid portion, the Occipito- 
frontalis, Sterno-mastoid, Splenius capitis, Trachelo-mastoid, Digastricus, and 
Retrahens aurem; to the styloid process, the Stylo-pharyngeus, Stylo-hyoideus, 
and Stylo-glossus ; and to the petrous portion, the Levator palati, Tensor 
tympani, Tensor palati, and Stapedius. 
The Sphenoid Bone (Os Sphenoidale). 
The sphenoid bone (fftpyv, a wedge) is situated at the anterior part of the base 
of the skull, articulating with all the other cranial bones, which it binds firmly 
and solidly together. In its form it somewhat resembles a bat with its wings 
extended; and is divided into a central portion or body, two greater and two lesser 
wings extending outward on each side of the body, and two processes-the ptery- 
goid processes-which project from it below. 
The Body of the Sphenoid Bone. 
The body (corpus) is of large size and hollowed out in its interior so as to form a 
mere shell of bone. It presents for examination four surfaces-a superior, an 
inferior, an anterior, and a posterior. THE SPHENOID BONE 
93 
Surfaces. Superior Surface (facies cerebralis) (Fig. 53).-In front is seen a promi- 
nent spine, the ethmoidal spine, for articulation with the cribriform plate of the eth- 
moid; behind this a smooth surface presenting, in the median line, a slight longi- 
tudinal eminence, with a depression on each side for lodging the olfactory lobes. 
This surface is bounded behind by a ridge, which forms the anterior border of a 
narrow, transverse groove, the optic groove (sulcus chiasmatis), behind which lies the 
optic chiasm; the groove is continuous on each side with the optic foramen (foramen 
opticum), for the passage of the optic nerve and ophthalmic artery. Behind the 
Posterior clinoid process. 
Middle clinoid process. 
Groove for 
olfactory 
tract. 
Ethmoidal 
spine. 
Foramen opticum.. 
Foramen lacerum ante- 
rius or Sphenoidal' 
fissure. 
Foramen rotundum.' 
Foramen spinosum. 
Foramen Vesalii.' 
Foramen ovale.' 
For 6th nerve. 
Petrosal 
process. 
Fig. 53.-Sphenoid bone. Superior surface. 
optic groove is a small eminence, olive-like in shape, the olivary process or eminence 
(tuberculum sella); and still more posteriorly, a deep depression, the pituitary fossa, 
or sella turcica (fossa hypophyseos), which lodges the circular sinus and the pituitary 
body (hypophysis'). This fossa is perforated by numerous foramina, for the trans- 
mission of nutrient vessels into the substance of the bone. It is bounded in front 
by the olivary eminence, and also by two small eminences, one on either side, called 
the middle clinoid processes (processus clinoidei medii) (xAivy, a bed), which are 
sometimes connected by a spiculum of bone to the anterior clinoid processes. It 
is bounded behind by a square-shaped plate of bone, the dorsum ephippii or dorsum 
sellae, terminating at each superior angle in a tubercle, the posterior clinoid process 
(processus clinoideus posterior). The size and form of these processes vary con- 
siderably in different individuals. They deepen the pituitary fossa, and serve for 
the attachment of prolongations from the tentorium cerebelli. The sides of the 
dorsum ephippii are notched for the passage of the sixth pair of nerves, and 
below present a sharp process, the petrosal process, which is joined to the apex 
of the petrous portion of the temporal bone, forming the inner boundary of the 
middle lacerated foramen. Behind this plate the bone presents a shallow depres- 
sion, which slopes obliquely backward, and is continuous with the basilar groove 
of the occipital bone; it is called the clivus, and supports the upper part of the 
pons Varolii. On either side of the body is a broad groove, curved something like 
the italic letter f; it lodges the internal carotid artery and the cavernous sinus, 
and is called the carotid or cavernous groove (sulcus caroticus). Along the outer 
margin of this groove, at its posterior part, is a ridge of bone in the angle 
between the body and greater wing, called the lingula (lingula sphenoidalis). 
Posterior Surface.-The posterior surface, quadrilateral in form, is joined to the 
basilar process of the occipital bone. During childhood these bones are separated 94 
THE SKELETON 
by a layer of cartilage; but in after-life (between the eighteenth and twenty-fifth 
years) this becomes ossified, ossification commencing above and extending down- 
ward; and the two bones then form one piece. 
Anterior Surface.-The anterior surface (Fig. 54) presents, in the middle line, a 
vertical ridge of bone, the ethmoidal or sphenoidal crest (crista sphenoidalis), which 
articulates in front with the perpendicular plate of the ethmoid, forming part of 
the septum of the nose. On either side of it are irregular openings leading into 
the sphenoidal cells or sinuses (sinus sphenoidales). These are two large, irregular 
cavities hollowed out of the interior of the body of the sphenoid bone, often 
Ethmoidal crest. 
Articulates with perpendicular 
plate of ethmoid. 
Orbital 
surface of 
greater wing. 
Pterygoid ridge.' 
Pterygo- 
palatine 
canal. 
\ Artic. with 
vomer. 
Groove for ala^ 
of vomer. 
Rostrum- 
Internal pterygoid plate.. 
Hamv.lar process. 
Fig. 54.-Sphenoid bone. Anterior surface.1 
extending into the pterygoid processes and base of the greater wings of the bone, 
and separated from one another by a more or less complete perpendicular bony 
septum (septum sinuum s pheno idalium). Occasionally they extend into the basilar 
process of the occipital nearly as far as the foramen magnum. Their form and 
size vary considerably; they are seldom symmetrical, and are often partially sub- 
divided by irregular, osseous lamime. One sinus or both sinuses may be absent. 
The septum is seldom quite vertical, being commonly bent to one or the other 
side. These sinuses do not exist in very young children, but appear, according 
to Laurent, in the seventh year, and, according to Tillaux, not until the twen- 
tieth year. After once appearing they increase in size as age advances. They 
are partially closed, in front and below, by two thin, curved plates of bone, 
the sphenoidal, spongy, or turbinated bones (conchae sphenoidales'). At the upper 
part of each is a round opening (apertura sinus sphenoidalis) by which the sinus 
communicates with the upper and back part of the nose, and occasionally with 
the posterior ethmoidal cells or sinuses. The lateral margins of this surface 
present a serrated edge, which articulates with the os planum of the ethmoid, 
completing the posterior ethmoidal cells; the lower margin, also rough and ser- 
rated, articulates with the orbital process of the palate bone, and the upper 
margin with the orbital plate of the frontal bone. 
Inferior Surface.-The inferior surface presents, in the middle line, a triangular 
spine, the rostrum (rostrum sphenoidalis), which is continuous with the sphenoidal 
crest on the anterior surface, and is received into a deep fissure between the alte 
1 In this figure, both the anterior and inferior surfaces of the body of the sphenoid bone are shown, the bone 
being held with the pterygoid processes almost horizontal. THE SPHENOID BONE 
95 
of the vomer. On each side may be seen a projecting lamina of bone, which runs 
horizontally inward from near the base of the pterygoid process: these plates, termed 
the vaginal processes, articulate with the edges of the vomer. Close to the root of 
the pterygoid process is a groove (sulcus pterygopalatinus), formed into a complete 
canal when articulated with the sphenoidal process of the palate bone; it is called 
the pterygo-palatine canal, and transmits the pterygo-palatine vessels and pharyngeal 
nerve. 
The Greater or Temporal Wings of the Sphenoid Bone (Alse Magnae). 
The greater wings are two strong processes of bone which arise from the sides 
of the body, and are curved in a direction upward, outward, and backward, each 
being prolonged behind into a sharp-pointed extremity, the alar or sphenoidal 
spine (spina angularis). Each wing presents three surfaces and a circumference. 
Surfaces. Superior Surface (facies cerebralis).-The superior or cerebral surface 
(Fig. 53) forms part of the middle fossa of the skull; it is deeply concave, and pre- 
sents eminences and depressions for the convolutions of the brain. At its anterior 
and internal part is seen a circular aperture, the foramen rotundum, for the transmis- 
sion of the second division of the fifth nerve. Behind and external to this is a large, 
oval foramen, the foramen ovale, for the transmission of the third division of the 
fifth nerve, the small meningeal artery, and sometimes the small petrosal nerve.1 
At the inner side of the foramen ovale a small aperture may occasionally be seen 
opposite the root of the pterygoid process; it is the foramen Vesalii, transmitting 
a small vein. Lastly, in the posterior angle, near to the spine of the sphenoid, is 
a short canal, sometimes double, the foramen spinosum; it transmits the middle 
meningeal artery. 
External Surface.-The external surface (Fig. 54) is convex and divided by a 
transverse ridge, the pterygoid ridge or infratemporal crest (crista infratemporalis), 
into two portions. The superior or larger, convex from above downward, concave 
from before backward, enters into the formation of the temporal fossa, and gives 
attachment to part of the Temporal muscle. The inferior portion, smaller in size 
and concave, enters into the formation of the zygomatic fossa, and affords attach- 
ment to the External pterygoid muscle. It presents, at its posterior part, a sharp- 
pointed eminence of bone, the spine, to which are connected the internal lateral 
ligament of the lower jaw and the Tensor palati muscle. The pterygoid ridge, 
dividing the temporal and zygomatic portions, gives attachment to part of the 
External pterygoid muscle. At its inner and anterior extremity is a triangular 
spine of bone, which serves to increase the extent of origin of this muscle. 
Anterior Surface (facies orbitalis).-The anterior or orbital surface, smooth and 
quadrilateral in form, assists in forming the outer wall of the orbit. It is bounded 
above by a serrated edge, for articulation with the frontal bone; below,by a rounded 
border which enters into the formation of the spheno-maxillary fissure. Internally, it 
presents a sharp border, which forms the lower boundary of the sphenoidal fissure, 
and has projecting from about its centre a little tubercle of bone, which gives 
origin to one head of the External rectus muscle of the eye; and at its upper part 
is a notch for the transmission of a recurrent branch of the lachrymal artery; 
externally it presents a serrated margin for articulation with the malar bone. One 
or two small foramina may occasionally be seen for the passage of branches of 
the deep temporal arteries; they are called the external orbital foramina. 
Circumference (Fig. 53).-Commencing from behind, that portion of the cir- 
cumference from the body of the sphenoid to the spine is serrated and articulates 
by its outer half with the petrous portion of the temporal bone, while the inner 
half forms the anterior boundary of the foramen lacerum medium, and presents 
1 The small petrosal nerve sometimes passes through a special foramen between the foramen ovale and 
foramen spinosum. 96 
THE SKELETON 
the posterior aperture of the Vidian canal (canalis pterygoideus) for the passage of the 
Vidian nerve and artery. In front of the spine the circumference of the great wing 
presents a serrated edge, bevelled at the expense of the inner table below and of the 
external above, which articulates with the squamous portion of the temporal bone. 
At the tip of the great wing a triangular portion is seen, bevelled at the expense of 
the internal surface, for articulation with the anterior inferior angle of the parietal 
bone. Internal to this is a triangular, serrated surface, for articulation with the 
frontal bone; this surface is continuous internally with the sharp inner edge of 
the orbital plate, which assists in the formation of the sphenoidal fissure, and 
externally with the serrated margin for articulation with the malar bone. 
The Lesser or Orbital Wings of the Sphenoid Bone (Alae Parvae). 
The lesser wings (processes of Ingrassias) are two thin, triangular plates of 
bone which arise from the upper and lateral parts of the body of the sphenoid, 
and, projecting transversely outward, terminate in a sharp point (Fig. 53). The 
superior surface of each is smooth, flat, broader internally than externally, and 
supports part of the frontal lobe of the brain. The inferior surface forms the 
back part of the roof of the orbit and the upper boundary of the orbital or sphe- 
noidal fissure or foramen lacerum anterius (fissura orbitalis superior). This fissure is 
of a triangular form, and leads from the cavity of the cranium into the orbit; it is 
bounded internally by the body of the sphenoid-above, by the lesser wing; 
below, by the internal margin of the orbital surface of the great wing-and is 
converted into a foramen by the articulation of this bone with the frontal. It 
transmits the third, the fourth, the three branches of the ophthalmic division 
of the fifth, the sixth nerve, some filaments from the cavernous plexus of the 
sympathetic, the orbital branch of the middle meningeal artery, a recurrent 
branch from the lachrymal artery to the dura mater and the ophthalmic vein. 
The anterior border of the lesser wing is serrated for articulation with the 
frontal bone; the posterior border, smooth and rounded, is received into the fissure of 
Sylvius of the brain. Each inner extremity of this border forms an anterior clinoid 
process (processus clinoideus anterior). The lesser wing is connected to the side 
of the body by two roots, the upper thin and flat, the lower thicker, obliquely 
directed, and presenting on its outer side, near its junction with the body, a small 
tubercle, for the attachment of the common tendon of origin of three of the muscles 
of the eye. Between the two roots is the optic foramen (foramen opticum), for 
the transmission of the optic nerve and ophthalmic artery. 
The Pterygoid Processes of the Sphenoid Bone (Processus Pterygoidei). 
The pterygoid processes a wing; likeness), one on each side, 
descend perpendicularly from the point where the body and greater wing unite 
(Fig. 55). Each process consists of an external and an internal lamina or plate, 
which are joined together by their anterior borders above, but are separated below, 
leaving an angular cleft, the pterygoid notch or fissure (fissura pterygoidea), in which 
the pterygoid process or tuberosity of the palate bone is received. The two plates 
diverge from each other from their line of connection in front, so as to form a V- 
shaped fossa, the pterygoid fossa (fossa pterygoidea). The external pterygoid plate 
(lamina lateralis processus pterygoidei) is broad and thin, turned a little outward, 
and, by its outer surface, forms part of the inner wall of the zygomatic fossa, giving 
attachment to the External pterygoid; its inner surface forms part of the pterygoid 
fossa, and gives attachment to the Internal pterygoid. The internal pterygoid plate 
(lamina medialis processus pterygoidei) is much narrower and longer, curving 
outward, at its extremity, into a hook-like process of bone, the hamular process THE SPHENOID BONE 
97 
(hamulus pterygoideus), around which turns the tendon of the Tensor palati 
muscle. The outer surface of this plate forms part of the pterygoid fossa, the 
inner surface forming the outer boundary of the posterior aperture of the nares. 
On the posterior surface of the base of the process, above the pterygoid fossa, is a 
small, oval, shallow depression, the scaphoid fossa (fossa scaphoidea), from which 
arises the Tensor palati, and above which is seen the posterior orifice of the Vidian 
canal (canalis pterygoideus [Vidii]). Below and to the inner side of the Vidian 
Fig. 55.-Sphenoid bone. Posterior surface. 
canal, on the posterior surface of the base of the internal plate, is a little promi- 
nence, which is known by the name of the pterygoid tubercle. The Superior 
constrictor of the pharynx is attached to the posterior edge of the internal plate. 
The anterior surface of the pterygoid process is very broad at its base, and forms 
the posterior wall of the spheno-maxillary fossa. It supports Meckel's ganglion. 
It presents, above, the anterior orifice of the Vidian canal; and below, a rough 
margin, which articulates with the perpendicular plate of the palate bone. 
The Sphenoidal Spongy Bone. 
The sphenoidal spongy, turbinal or turbinated bones (the bones of Bertin, concha; 
sphenoidales) are two thin, curved plates of bones, which exist as separate pieces 
until puberty, and occasionally are not joined to the sphenoid in the adult. They 
are situated at the anterior and inferior part of the body of the sphenoid, an 
aperture (apertura sinus sphenoidalis) of variable size being left in the anterior wall 
of each, through which the sphenoidal sinuses open into the nasal fossae. They are 
irregular in form and taper to a point behind, being broader and thinner in front. 
Their upper surface, which looks toward the cavity of the sinus, is concave; their 
under surface convex. Each bone articulates in front with the ethmoid, exter- 
nally with the palate; its pointed posterior extremity is placed above the vomer, 
and is received between the root of the pterygoid process on the outer side and 
the rostrum of the sphenoid on the inner.1 
Development.-Up to about the eighth month of foetal life the sphenoid bone 
consists of two distinct parts: a posterior or post-sphenoid part, which comprises 
the pituitary fossa, the greater wings, and the pterygoid processes; and an anterior 
or pre-sphenoid part, to which the anterior part of the body and lesser wings 
belong. It is developed by fourteen centres: eight for the posterior sphenoid, 
division, and six for the anterior sphenoid. The eight centres for the posterior 
1 A small portion of the sphenoidal turbinated bone sometimes enters into the formation of the inner wall of 
the orbit, between the os planum of the ethmoid in front, the orbital plate of the palate below, and the frontal 
above.-Cleland, Roy. Soc. Trans., 1862. 98 
THE SKELETON 
sphenoid are: one for each greater wing and external pterygoid plate, one for 
each internal pterygoid plate, two for the posterior part of the body, and one on 
each side for the lingula. The six for the anterior sphenoid are: one for each 
lesser wing, two for the anterior part of the body, and one for each sphenoidal 
turbinated bone. 
Post-sphenoid Division.-The first nuclei to appear are those for the greater 
wings (ali-sphenoids). They make their appearance between the foramen rotun- 
dmn and foramen ovale about the eighth 
week, and from them the external pterygoid 
plates are also formed. Soon after, the 
nuclei for the posterior part of the body 
appear, one on either side of the sella turcica, 
and become blended together about the 
middle of foetal life. About the fourth 
month the remaining four centres appear, 
those for the internal pterygoid plates being 
ossified in membrane and becoming joined 
to the external pterygoid plate about the 
sixth month. The centres for the linguke 
speedily become joined to the rest of the 
bone. 
Pre-sphenoid Division.-The first nuclei 
to appear are those for the lesser wings 
{orbito-sphenoids). They make their appearance about the ninth week, at the 
outer borders of the optic foramina. A second pair of nuclei appear on the inner 
side of the foramina shortly after, and, becoming united, form the front part of 
the body of the bone. The remaining two centres for the sphenoidal turbinated 
bones make their appearance about the fifth month. At birth they consist of small 
triangular laminae, and it is not till the third year that they become hollowed out 
and cone-shaped. About the fourth year they become fused with the lateral 
masses of the ethmoid, and hence, from an embryological point of view, may be 
regarded as belonging to the ethmoid. 
The pre-sphenoid is united to the body of the post-sphenoid about the eighth 
month, so that at birth the bone consists of three pieces-viz., the body in the 
centre, and on each side the great wings with the pterygoid processes. The lesser 
wings become joined to the body at about the time of birth. At the first year 
after birth the greater wings and body are united. From the tenth to the twelfth 
year the spongy bones are partially united to the sphenoid, their junction being 
complete by the twentieth year. Lastly, the sphenoid joins the occipital from the 
eighteenth to the twenty-fifth year. 
Articulations.-The sphenoid articulates with all the bones of the cranium, 
and five of the face-the two malar, the two palate, and vomer; the exact extent 
of articulation with each bone is shown in the accompanying figures.1 
Attachment of Muscles.-To eleven pairs: the Temporal, External pterygoid, 
Internal pterygoid, Superior constrictor, Tensor palati, Levator palpebne, Ob- 
liquus oculi superior, Superior rectus, Internal rectus, Inferior rectus, External 
rectus. 
one for each 
lesser wing. 
two for anterior 
part of body. 
one for each internal. 
pterygoid plate. 
one for 
each great wing and external ptery- 
[goid plate. 
one 
for each lingula. 
one for each Sphenoidal turbinated bone. 
Fig. 56.-Plan of development of the sphenoid. 
By fourteen cehtres. 
The Ethmoid Bone (Os Ethmoidale). 
The ethmoid a sieve) is an exceedingly light, spongy bone, of a cubical 
form, situated at the anterior part of the base of the cranium, between the two 
orbits at the root of the nose, and contributing to form each of these cavities. 
1 It also sometimes articulates with the tuberosity of the superior maxilla. THE ETHMOID BONE 
99 
It consists of three parts: a horizontal plate, which forms part of the base of the 
cranium; a perpendicular plate, which forms part of the septum nasi; and two 
lateral masses of cells. 
The Horizontal Lamina or Cribriform Plate (lamina cribrosa) (Fig. 57) forms 
part of the anterior fossa of the base of the skull, and is received into the ethmoid 
notch of the frontal bone be- 
tween the two orbital plates. 
Projecting upward from the 
middle line of this plate is a 
thick, smooth, triangular pro- 
cess of bone, the crista galli, so 
called from its fancied resem- 
blance to a cock's comb. Its 
base joins the cribriform plate. 
Its posterior border, long, thin, 
and slightly curved, serves for 
the attachment of the falx cere- 
bri. Its anterior border, short 
and thick, articulates with the 
frontal bone, and presents two 
small projecting alae (processus 
alares), which are received in- 
to corresponding depressions 
in the frontal, completing the 
fcramen caecum behind. Its sides are smooth and sometimes bulging; in which 
case it is found to enclose a small sinus.1 On each side of the crista galli the cribri- 
form plate is narrow and deeply grooved, to support the bulb of the olfactory tract, 
and is perforated by foramina for the passage of the olfactory nerves. These fora- 
With inferior turbinated bone. 
Fig. 57.-Ethmoid bone. Outer surface of right lateral mass 
(enlarged). 
LAMINA CRIBROSA 
CRISTA GALLI 
ALAR PROCESS 
POSTERIOR 
ETHMOIDAL 
FORAMEN 
lamina cribrosa 
ANTERIOR 
ETH MOI DAL 
FORAMEN 
CRISTA GALLI 
UNCIFORM 
PROCESS 
ALAR PROCESS 
ETHMOIDAL 
LABYRINTH 
PERPENDICU- 
LAR LAMINA 
Fig. 58.-Ethmoid bone from behind, somewhat 
schematic. (Spalteholz.) 
Fig. 59.-Ethmoid bone from above. (Spalteholz.) 
mina are arranged in three rows: the innermost, which are the largest and least 
numerous, are lost in grooves on the upper part of the septum; the foramina of the 
outer row are continued on to the surface of the upper spongy bone. The fora- 
mina of the middle row are the smallest; they perforate the bone and transmit 
nerves to the roof of the nose. At the front part of the cribriform plate, on each 
1 Sir George Humphry states that the crista galli is commonly inclined to one side, usually the opposite to 
that toward which the lower part of the perpendicular plate is bent.-The Human Skeleton, 1858, p. 277. 100 
THE SKELETON 
side of the crista galli, is a small fissure, which transmits the nasal branch of the 
ophthalmic nerve; and at its posterior part a triangular notch, which receives the 
ethmoidal spine of the sphenoid. 
The Vertical or Perpendicular Lamina or Plate (lamina perpendicular is or 
me s ethmoid) (Fig. 60) is a thin, flattened lamella of bone, which descends from the 
under surface of the cribriform plate, and assists in forming the septum of the nose. 
It is much thinner in the middle than at the circumference, and is generallydeflected 
a little to one side. Its anterior border articulates with the nasal spine of the frontal 
bone and crest of the nasal bones. Its posterior border, divided into two parts, 
articulates by its upper 
half with the sphenoidal 
crest of the sphenoid, by 
its lower half with the 
vomer. The inferior bor- 
der serves for the attach- 
ment of the triangular car- 
tilage of the nose. On 
each side of the perpen- 
dicular plate numerous 
grooves and canals are 
seen, leading from the for- 
amina on the cribriform 
plate; they lodge filaments 
of the olfactory nerves. 
The Lateral Mass or 
Labyrinth (labyrinthus 
ethmoidalis) of the ethmoid 
consists of a number of 
thin-walled cellular cavities, the ethmoidal cells (cellulm ethmoidales) interposed be- 
tween two vertical plates of bone, the outer one of which forms part of the orbit, 
and the inner one part of the nasal fossa of the corresponding side. There are two 
lateral masses, one on each side. The ethmoidal cells are not present at birth, 
but appear during the fifth year. In the disarticulated bone many of these cells 
appear to be broken; but when the bones are articulated they are closed in at 
every part, except where they open into the nasal fossae. The upper surface of 
each lateral mass presents a number of apparently half-broken cellular spaces; 
these are closed in, when articulated, by the edges of the ethmoidal notch of the 
frontal bone. Crossing this surface are two grooves on each side, converted into 
canals by articulation with the frontal; they are the anterior and posterior ethmoidal 
canals (canalis ethmoidale anterius and posterius), and open on the inner wall of 
the orbit. The posterior surface also presents large, irregular cellular cavities, 
which are closed in by articulation with the sphenoidal turbinated bones and 
the orbital process of the palate. The cells at the anterior surface are completed 
by the lachrymal bone and nasal process of the superior maxillary, and those 
below also by the superior maxillary. The outer surface of each lateral mass is 
formed of a thin, smooth, oblong plate of bone, called the os planum (lamina 
papyracea); it forms part of the inner wall of the orbit, and articulates, above, 
with the orbital plate of the frontal; below, with the superior maxillary; in 
front, with the lachrymal; and behind, with the sphenoid and orbital process of 
the palate. 
From the inferior part of each lateral mass, immediately beneath the os planum, 
there projects downward and backward an irregular lamina of bone, called the 
unciform process (processus uncinafus), from its hook-like form; it serves to close 
in the upper part of the orifice of the antrum, and articulates wTith the ethmoidal 
Perpendicular Plate 
Fig. 60.-Perpendicular plate of ethmoid (enlarged), shown by 
removing the right lateral mass. THE ETHMOID BONE 
101 
process of the inferior turbinated bone. It is often broken in disarticulating the 
bones. 
The inner surface of each lateral mass forms part of the outer wall of the nasal 
fossa of the corresponding side. It is formed of a thin lamella of bone, which 
descends from the under surface of the cribriform plate, and terminates below in 
a free, convoluted margin, the middle turbinated or the inferior ethmoidal turbinate 
bone (concha nasalis media). The middle turbinated bone may contain a cell or 
cells, which are really ethmoidal cells. Howard A. Lothrop1 studied 1000 speci- 
mens, and found cells in 9 per cent. 
of them. He never found cells in 
children. As a rule, a turbinate cell 
communicates with a posterior eth- 
moidal cell, but may join an anterior 
ethmoidal cell. The cells may open 
into the superior meatus or into the 
middle meatus. The whole of this 
surface is rough and marked above 
by numerous grooves, which run nearly 
vertically downward from the cribri- 
form plate; they lodge branches of the 
olfactory nerve, which are distributed 
on the mucous membrane covering the 
bone. The back part of this surface is subdivided by a narrow oblique fissure, the 
superior meatus of the nose (meatus nasi superior), bounded above by a thin, curved 
plate of bone, the superior turbinated bone (.concha nasalis superior). By means of an 
orifice at the upper part of this fissure the posterior ethmoidal cells open into the 
nose. Below, and in front of the superior meatus, is seen the convex surface of 
the middle turbinated bone. It extends along the whole length of the inner sur- 
face of each lateral mass; its lower margin is free and thick, and its concavity, 
directed outward, assists in forming the middle meatus. It is by a large orifice 
at the upper and front part of the middle meatus that the anterior ethmoidal cells, 
and through them the frontal sinuses, communicate with the nose by means of a 
funnel-shaped canal, the infundibulum (infundibulum ethmoidale). The cellular 
cavities of each lateral mass, thus walled in by the os planum on the outer side and 
by the other bones already mentioned, are divided by a thin transverse bony parti- 
tion into two sets, which do not communicate with each other; they are termed 
the anterior and posterior ethmoidal cells or sinuses. The former, more numerous, 
communicate with the frontal sinuses above and the middle meatus below by 
means of a long, flexuous canal, the infundibulum; the posterior, less numerous, 
open into the superior meatus and communicate (occasionally) with the sphe- 
noidal sinuses. In some cases the ethmoidal sinuses communicate with the maxil- 
lary sinus. In some cases the os planum never develops, and the ethmoidal 
sinuses are separated from the orbit merely by membrane. 
Development.-By three centres: one for the perpendicular lamella, and one 
for each lateral mass. The lateral masses are first developed, ossific granules 
making their appearance in the os planum between the fourth and fifth months 
of foetal life, and extending into the spongy bones. At birth the bone consists of 
the two lateral masses, which are small and ill-developed. During the first year 
after birth the perpendicular plate and crista galli begin to ossify, from a single 
nucleus, and become joined to the lateral masses about the beginning of the second 
year. The cribriform plate is ossified partly from the perpendicular plate and 
partly from the lateral masses. The formation of the ethmoidal cells, which com- 
pletes the bone, does not commence until the end of the fourth year. 
Fig. 61.-Ethmoid bone. Inner surface of right lateral 
mass (enlarged). 
1 Annals of Surgery, May, 1903. 102 
THE SKELETON 
Articulations.-With fifteen bones: the sphenoid, two sphenoidal turbinated, 
the frontal, and eleven of the face-the two nasal, two superior maxillary, two 
lachrymal, two palate, two inferior turbinated, and the vomer. No muscles are 
attached to this bone. 
The cerebral vesicles became enclosed by an envelope of membrane derived from the em- 
bryonic connective tissue about the head end of the chorda. This sac from the mesoderm 
is converted into fibrous tissue, and is known as the membranous cranium. In adult life 
the dura mater represents the membranous cranium. 
In mammals the base and part of the sides of the membranous cranium become cartilaginous, 
but the roof and the remaining part of the sides remain membranous. Ossification com- 
mences in the roof and begins at a later period in the base. Although ossification begins in 
the membrane bones before it does in the cartilage bones, and the bones of the roof appear 
before the bones of the base and make considerable progress in their growth, at birth ossification 
is more advanced in the base, this portion of the skull forming a solid, immovable groundwork. 
The Skull at Different Ages. -The skull at birth is relatively of large size as compared 
with the body. The cerebral cranium is large and the face is small. The fontanelles are 
open (see below). There are no sutures, but the margins of adjacent bones are widely sepa- 
rated by fibrous tissue which runs from the periosteum to the dura mater. The bones of the 
vault have no diploe and digital impressions are absent on the cranial surfaces. The parietal 
eminences and the frontal eminences are very distinct.1 
The orbits and parietal bones are large. If the base is examined it is noted that the 
mastoid processes are absent, that the lower border of the symphysis of the jaw is on a level 
with the condyles of the occipital bone, and that the pterygoid plates form " a large angle with 
the skull base, whereas in the adult the angle is almost a right one." 2 The lower jaw at birth 
is shown in Fig. 91. 
The development of individual bones is considered under the appropriate headings. At 
puberty various pneumatic cells develop in bone and alter the form of the head and face. 
After the eruption of the first set of teeth the age can be determined with reasonable cer- 
tainty, and the degree of obliteration of the sutures will also give valuable information. In 
the vast majority of individuals the metopic suture becomes a mere trace during the fifth or 
sixth years. Ossification at the junction of the coronal and sagittal sutures and osseous union 
of the sphenoid and basilar portion of the occipital occur during maturity. The lower jaw of 
an adult is shown in Fig. 93. 
In old age much of the diploe disappears and the bones become thinner and more porous. 
The alveolar surfaces of the jaws are absorbed if the teeth are lost, and the lower jaw alters 
its form (Fig. 94). 
Sexual Differences.-It is not always possible to tell with certainty a woman's skull from 
a man's, but certain features are of value in reaching a conclusion. Virchow maintained that 
in non-European races it is very difficult to determine the sex from the skull, though among 
some savage races the differences may be great.3 It is always to be borne in mind that a 
woman's skull may he of the masculine type and a man's skull may be of the feminine type. 
There is no constant characteristic significant of the male or female skull. As a general rule, 
the female skull is smaller than the male; it is lighter, the muscular ridges and processes are 
less distinct, the mastoid processes are of less size, the orbital margins are thin and sharp 
(Cunningham), the forehead is more vertical and the vertex is more flattened (Cunningham), 
and the edge of the tympanic plate is " rounder and more tuberculous " (Cunningham). The 
frontal air sinuses are smaller in women than in men, one reason why the glabella is more 
prominent in men. The flattening of the vertex in women, previously referred to, causes 
the top of the head to be at a more marked angle with the forehead than in men (Ecker). 
This characteristic was recognized by the Greek sculptors (Havelock Ellis). The cephalic 
index, which shows the relation of skull breadth to skull length, is of doubtful value in 
determining sex. 
DEVELOPMENT OF THE CRANIUM 
The Fontanelles (Fonticuli). 
Before birth the bones at the vertex and side of the skull are separated from each other by 
membranous intervals in which bone is deficient. These intervals are principally found at the 
four angles of the parietal bones. Hence there are six fontanelles. Their formation is due to 
the wave of ossification being circular and the bones quadrilateral; the ossific matter first meets 
at the margins of the bones, at the points nearest to their centres of ossification, and vacuities 
1 J. Bland Sutton in Henry Morris' Human Anatomy. 2 Ibid. 
3 Man and Woman, by Havelock Ellis. SUPERNUMERARY, WORMIAN OR SUTURAL BONES 
103 
or spaces are left at the angles, which are called fontanelles, so named from the pulsations of 
the brain, which are perceptible at the anterior fontanelle, were likened to the rising of water 
in a fountain. The anterior or bregmatic fontanelle (jonticulus frontalis) is the largest; it is 
lozenge-shaped, and corresponds to the junction of the sagittal and coronal sutures; the pos- 
terior fontanelle (fonticulus occipitalis), of smaller size, is triangular, and is situated at the 
junction of the sagittal and lambdoid sutures; the remaining ones, the antero-lateral and the 
postero-lateral fontanelles (jonticulus sphenoidalis et jonticulus mastoideus), are situated at the 
inferior angles of each parietal bone. The latter are closed soon after birth; the two at the two 
superior angles remain open longer; the posterior being closed in a few months afterbirth; the 
anterior remaining open until the first or second year. These spaces are gradually filled in by an 
extension of the ossifying process or by the development of a Wormian bone. Sometimes the ante- 
rior fontanelle remains open beyond two years, and is occasionally persistent throughout life. 
Supernumerary, Wormian,1 Sutural or Epactal Bones (Ossa Triquetra). 
In addition to the constant centres of ossification of the skull, additional ones are occasion- 
ally found in the course of the sutures. These form irregular, isolated bones, interposed between 
the cranial bones, and have been termed Wormian bones or ossa triquetra. They are most 
Fig. 62.-Skull at birth, showing the anterior and 
posterior fontanelles. 
Fig. 63.-The lateral fontanelles. 
frequently found in the course of the lambdoid suture, but occasionally also occupy the situation 
of the fontanelles, especially the posterior and, more rarely, the anterior. Frequently one is 
found between the anterior inferior angle of the parietal bone and the greater wing of the 
Fig. 64.-Wormian bones. 
Fig. 65. 
Fig. 66. 
sphenoid, the epicteric bone or the pterion ossicle (Fig. 63). They have a great tendency to be 
symmetrical on the two sides of the skull, and they vary much in size, being in some cases not 
larger than a pin's head, and confined to the outer table; in other cases so large that one pair of 
these bones may form the whole of the occipital bone above the superior curved lines, as described 
1 Wormius, a physician of Copenhagen, is said to have given the first detailed description of these bones. 104 
THE SKELETON 
by Beclard and Ward. Their number is generally limited to two or three, but more than a 
hundred have been found in the skull of an adult hydrocephalic skeleton. In their development, 
structure, and mode of articulation they resemble the other cranial bones. 
Congenital Fissures and Gaps. 
An arrest in the ossifying process may give rise to deficiencies or gaps; or to fissures, which 
are of importance in a medico-legal point of view, as they are liable to be mistaken for fractures. 
The fissures generally extend from the margins toward the centre of the bone, but the gaps 
may be found in the middle as well as at the edges. In course of time they may become covered 
with a thin lamina of bone. 
The Facial Bones are fourteen in number-viz., the 
BONES OF THE FACE (OSSA FACIEI). 
Two Nasal. 
Two Superior Maxillae. 
Two Lachrymal. 
Two Malar. 
Two Palate. 
Two Inferior Turbinated. 
Vomer. 
Inferior Maxilla or Mandible. 
"Of these, the upper and lower jaws are the fundamental bones for mastication, 
and the others are accessories; for the chief function of the facial bones is to 
provide an apparatus for mastication, while subsidiary functions are to provide for 
the sense organs (eye, nose, tongue) and a vestibule to the respiratory and vocal 
organs. Hence the variations in the shape of the face in man and the lower 
animals depend chiefly on the question of the character of their food and their 
mode of obtaining it."1 
The Nasal Bones (Ossa Nasalia). 
The nasal (nasus, the nose) are two small oblong bones, varying in size and 
form in different individuals; they are placed side by side at the middle and upper 
Nasal bone- 
Nasal proc. 
Lachrymal bone. 
Orbital surface. 
Infra-orbital 
groove. 
Infra-orbital 
foramen. 
Artic, with malar. 
Ant. nasal spine. 
Post, dental 
canals. 
Maxillary 
tuberosity. 
Alveolar 
process. 
Fig. 67.-Nasal and lachrymal bones in situ. 
part of the face, forming, by their junction, "the bridge" of the nose (Fig. 67). 
Each bone presents for examination two surfaces and four borders. 
1 W. W. Keen, American edition, 1887, p. 185. THE SUPERIOR MAXILLARY BONES 
105 
Surfaces. Outer Surface.-The outer surface is concave from above downward, 
convex from side to side; it is covered by the Pyramidalis and Compressor nasi 
muscles, and gives attachment at its upper part to a few fibres of the Occipito- 
frontalis muscle (Theile). It is marked by numerous small arterial furrows, and 
perforated about its centre by a foramen (foramen nasale), sometimes double, 
for the transmission of a small vein. 
Inner Surface.-The inner surface is concave from side to side, convex from 
above downward; in which direction it is traversed by a longitudinal groove 
(sometimes a canal), for the 
passage of a branch of the nasal 
nerve. 
Borders. Superior Border.- 
The superior border is narrow, 
thick, and serrated, for articula- 
tion with the nasal notch of the 
frontal bone. 
Inferior Border.-The inferior 
border is broad, thin, sharp, in- 
clined obliquely downward, out- 
ward, and backward, and serves 
for the attachment of the lateral 
cartilage of the nose. This bor- 
der presents, about its middle, a notch, through which passes the branch of the 
nasal nerve above referred to, and is prolonged at its inner extremity into a sharp 
spine, which, when articulated with the opposite bone, forms the nasal angle. 
External Border.-The external border is serrated, bevelled at the expense of 
the internal surface above and of the external below, to articulate with the nasal 
process of the superior maxillary. 
Internal Border.-The internal border, thicker above than below, articulates 
with its fellow of the opposite side, and is prolonged behind into a vertical crest, 
which forms part of the septum of the nose; this crest articulates above down- 
ward with the nasal spine of the frontal above, and the perpendicular plate of 
the ethmoid, and the triangular septal cartilage of the nose. 
Development.-By one centre for each bone, which appears about the eighth week. 
Articulations.-With four bones: two of the cranium, the frontal and ethmoid, 
and two of the face, the opposite nasal and the superior maxillary. 
Attachment of Muscles.-A few fibres of the Occipito-frontalis muscle. 
With frontal bone. 
With 
frontal spine. 
With 
opposite bone. 
Crest. 
With 
■perpendicular 
plate of 
ethmoid. 
Groove for nasal nerve. 
Outer Surface. 
Inner Surface. 
Fig. 68.-Right nasal bone. 
Fig. 69.-Left nasal bone. 
The Superior Maxillary Bones (Upper Jaw Bones or Maxillae). 
The superior maxillae (maxilla, the jaw bone) are the most important bones 
of the face from a surgical point of view, on account of the number of diseases to 
which some of their parts are liable. Their careful examination becomes, there- 
fore, a matter of considerable interest. They are the largest bones of the face, 
excepting the lower jaw, and form, by their union, the whole of the upper jaw. 
Each maxilla assists in the formation of three cavities, the roof of the mouth, the 
floor and outer wall of the nasal fossie, and the floor of the orbit, and also enters 
into the formation of two fossae, the zygomatic and spheno-maxillary, and two 
fissures, the spheno-maxillary and pterygo-maxillary. The bone presents for exam- 
ination a body and four processes-malar, nasal, alveolar, and palate. 
The body is somewhat cuboid and is hollowed out in its interior to form a 
large cavity, the antrum of Highmore (sinus maxillaris). Its surfaces are four- 
The Body of the Superior Maxilla u (Corpus Maxillae). 106 
THE SKELETON 
an external or facial, a posterior or zygomatic, a superior or orbital, and an 
internal or nasal. 
Surfaces. External Surface {facies anterior).-The external anterior or facial 
surface (Fig. 70) is directed forward and outward. It presents at its lower part a 
series of eminences corresponding to the position of the anterior five alveoli (juga 
alveolar ia). Just above those1 for the incisor teeth is a depression, the incisive or 
myrtiform fossa, which gives origin to the Depressor ahe nasi; and below it to the 
alveolar border is attached a slip of the Orbicularis oris. Above and a little exter- 
nal to it the Compressor nasi arises. More external is another depression, the 
canine fossa (fossa canina), larger and deeper than the incisive fossa, from which it 
is separated by a vertical ridge, the canine eminence, corresponding to the socket of 
the canine tooth. The canine fossa gives origin to the Levator anguli oris. Above 
the canine fossa is the infraorbital foramen (foramen infraorbitale), the termination 
Outer Surface. 
Lachrymal tubercle. 
TENDO OCULI.< 
Orbital Surfa ce 
Posterior dental 
canals. 
Incisive fossa.- 
Maxillary tuberosity. 
Bicuspids. 
Fig. 70.- Left superior maxilla. Outer surface. 
of the infraorbital canal; it transmits the infraorbital vessels and nerve. Some- 
times the infraorbital canal opens by two, very rarely by three, orifices on the 
face. Above the infraorbital foramen is the margin of the orbit (margo infraor- 
bitalis), which affords partial attachment to the Levator labii superioris proprius. 
To the sharp margin of bone which bounds this surface in front and separates 
it from the internal surface is attached the Dilator naris posterior. 
Posterior Surface (facies infratemporalis).-The posterior or zygomatic or infra- 
temporal surface is convex, directed backward and outward, and forms part of the 
zygomatic fossa. It is separated from the facial surface by a strong ridge of bone, 
the malar process, which extends upward from the socket of the second molar 
tooth. It presents about its centre several apertures leading to canals in the 
substance of the bone; they are termed the posterior dental canals (foramina alveo- 
laria), and transmit the posterior dental vessels and nerves. At the lower part of 
this surface is a rounded eminence, the maxillary tuberosity (tuber maxi Hare), 
especially prominent after the growth of the wisdom-tooth, rough on its inner THE SUPERIOR MAXILLARY BOXES 
107 
side for articulation with the tuberosity of the palate bone, and sometimes with 
the external pterygoid plate. It gives attachment to a few fibres of origin of 
the Internal pterygoid muscle. Immediately above this is a smooth surface, 
which forms the anterior boundary of the spheno-maxillary fossa; it presents a 
groove which, running obliquely downward, is converted into a canal by articu- 
lation with the palate bone, forming the posterior palatine or palato-maxillary canal 
for the descending palatine artery and great palatine nerve. 
Superior Surface (facies orbitalis).-The superior or orbital surface is thin, 
smooth, triangular, and forms part of the floor'of the orbit. It is bounded in- 
ternally by an irregular margin which in front presents a notch, the lachrymal notch 
(incisura lacrimalis), which receives the lachrymal bone; in the middle articulates 
with the os planum of the ethmoid, and behind with the orbital process of the 
palate bone; bounded externally by a smooth, rounded edge which enters into the 
formation of the spheno-maxillary fissure, and which sometimes articulates at its 
anterior extremity with the orbital plate of the sphenoid; bounded in front by part 
of the circumference of the orbit, which is continuous on the inner side with the 
nasal, on the outer side with the malar process. Along the middle line of the orbital 
surface is a deep groove, the infraorbital groove (sulcus infraorbitalis), for the pas- 
sage of the infraorbital vessels and nerve. The groove commences at the middle 
of the outer border of this surface, and, passing forward, terminates in a canal, 
which subdivides into two branches. One of the canals, the infraorbital canal 
(canalis infraorbitalis), opens just below the margin of the orbit; the other, which 
is smaller, runs downward in the substance of the anterior wall of the antrum; 
it is called the anterior dental canal, and transmits the anterior dental vessels 
and nerve to the front teeth of the upper jaw. From the back part of the 
infraorbital canal a second small canal is sometimes given off, which runs down- 
ward in the outer wall of the antrum, and conveys the middle dental nerve to 
the bicuspid teeth. Occasionally this canal is derived from the anterior dental. 
At the inner and fore part of the orbital surface, just external to the lachrymal 
groove for the nasal duct, is a depression which gives origin to the Inferior oblique 
muscle of the eye. 
Internal Surface (facies nasalis).-The internal or nasal surface (Fig. 71) is 
unequally divided into two parts by a horizontal projection of bone, the palate 
process (processus palatinus): the portion above the palate process forms part of 
the outer wall of the nasal fossa?; that below it forms part of the cavity of the 
mouth. The superior division of this surface presents a large, irregular opening, 
the maxillary hiatus (hiatus maxillaris), leading into the antrum of Highmore. 
At the upper border of this aperture are numerous broken cellular cavities, which 
in the articulated skull are closed in by the ethmoid and lachrymal bones. Below 
the aperture is a smooth concavity which forms part of the inferior meatus of the 
nasal fosste, and behind it is a rough surface which articulates with the perpendic- 
ular plate of the palate bone, traversed by a groove which, commencing near the 
middle of the posterior border, runs obliquely downward and forward, and forms, 
when completed by its articulation with the palate bone, the posterior palatine or 
palato-maxillary canal. In front of the opening of the antrum is a deep groove, 
converted into a canal (canalis nasolacrimalis) by the lachrypaal and inferior 
turbinated bones. The groove is called the lachrymal groove (sulcus lacrimalis), 
and lodges the nasal duct. More anteriorly is a well-marked rough ridge, the 
inferior turbinated crest (crista conchalis), for articulation with the inferior turbin- 
ated bone. The shallow concavity above this ridge forms part of the middle 
meatus of the nose, while that below it forms part of the inferior meatus. The 
portion of this surface below the palate process is concave, rough, and uneven, 
and perforated by numerous small foramina for the passage of nutrient vessels. 
It enters into the formation of the roof of the mouth. 108 
THE SKELETON 
The Antrum of Highmore, Maxillary Antrum, or Maxillary Sinus (sinus maxil- 
laris), is a pyramidal cavity hollowed out of the body of the maxillary bone. 
It varies much in size. It is in most cases a large cavity, but in some is very 
small. The apex of the antrum, directed outward, is formed by the malar process; 
Bones partially closing orifice of antrum 
marked in outline. 
Ethmoid. 
Inferior turbinated.. 
Palate. 
Anterior nasal spine. 
Bristle passed 
.through anterior 
palatine canal. 
Fig. 71.-Left superior maxilla. Internal surface. 
its base by the outer wall of the nose. Its walls are everywhere exceedingly thin, 
and correspond to the orbital, facial, and zygomatic surfaces of the body of the 
bone. The antral floor is, in most persons, on a level with the floor of the nasal 
fossa, but in some individuals it is on a lower level. Not unusually the inner 
wall of the antrum will be found to contain depressions or pockets. In rare 
instances an antral cavity is made into two by a bony septum. Its inner wall or 
base presents, in the disarticulated bone, a large, irregular aperture {hiatus 
maxillaris), which communicates with the nasal fossa. The margins of this 
aperture are thin and ragged, and the aperture itself is much contracted by its 
articulation with the ethmoid above, the inferior turbinated below, and the 
palate bone behind.1 In the articulated skull this cavity communicates with 
the middle meatus of the nasal cavity, generally by two small apertures left 
between the above-mentioned bones. In the recent state usually only one small 
opening exists, near the upper part of the cavity, sufficiently large to admit the 
end of a probe, the other being closed by the lining membrane of the sinus. That 
the opening into the nasal fossa does not afford the best drainage is demon- 
strated, when we note that it is at the highest and not at the lowest point of the 
antrum. "In rare instances the antrum communicates with the anterior eth- 
moidal cells, or the orbital and posterior ethmoidal cells and sphenoidal sinuses.''2 
At birth the antrum exists, though in a rudimentary state. It attains its full 
size from the twelfth to the fourteenth year. 
Crossing the cavity of the antrum are often seen several projecting laminae of 
bone, similar to those seen in the sinuses of the cranium; and on its posterior wall 
1 In some cases, at any rate, the lachrymal bone encroaches slightly on the anterior superior portion of the 
opening, and assists in forming the inner wall of the antrum. 
2 D. Kerfoot Shute, in the Reference Handbook of the Medical Sciences. THE SUPERIOR MAXILLARY BOXES 
109 
are the posterior dental canals, transmitting the posterior dental vessels and nerves 
to the teeth. Projecting into the floor are several conical processes, corresponding 
to the roots of the first and second molar teeth;1 in some cases the floor is per- 
forated by the teeth in this situation. 
It is from the extreme thinness of the walls of this cavity that we are enabled to explain how 
a tumor growing from the antrum encroaches upon the adjacent parts, pushing up the floor of 
the orbit, and displacing the eyeball, projecting inward into the nose, protruding forward on 
to the cheek, and making its way backward into the zygomatic fossa and downward into the 
mouth. 
The Processes of the Superior Maxillae. 
Malar Process {processus zygomaticus).-The malar process is a rough, trian- 
gular eminence, situated at the angle of separation of the facial from the zygo- 
matic surface. In front it is concave, forming part of the facial surface; behind 
it is also concave, and forms part of the zygomatic fossa; above it is rough and 
serrated for articulation with the malar bone; whilst below a prominent ridge 
marks the division between the facial and zygomatic surfaces. A small part of 
the Masseter muscle arises from this process. 
Nasal Process {processus frontalis).-The nasal process is a strong, triangular 
plate of bone, which projects upward, inward, and backward by the side of the 
nose, forming part of its lateral boundary. Its external surface is concave, smooth, 
perforated by numerous foramina, and gives attachment to the Levator labii 
superioris alaeque nasi, the Orbicularis palpebrarum, and Tendo oculi. Its 
internal surface forms part of the outer wall of the nasal fossae; at its upper 
part it presents a rough, uneven surface, which articulates with the ethmoid 
bone, closing in the anterior ethmoidal cells; below this is a transverse ridge, the 
superior turbinated crest {crista ethmoidalis), for articulation with the middle tur- 
binated bone of the ethmoid, bounded below by a shallow, smooth concavity 
which forms part of the middle meatus; below this again is the inferior turbinated 
crest (already described), where the process joins the body of the bone. Its upper 
border articulates with the frontal bone. The anterior border of the nasal process 
is thin, directed obliquely downward and forward, and presents a serrated edge for 
articulation with the nasal bone; its posterior border is thick, and hollowed into 
a groove, the lachrymal groove {sulcus lacrimalis), for the naso-lachrymal duct: of 
the two margins of this groove, the inner one articulates with the lachrymal bone; 
the outer one forms part of the circumference of the orbit. Just where the latter 
joins the orbital surface is a small tubercle, the lachrymal tubercle; this serves as 
a guide to the position of the lachrymal sac in the operation for fistula lachrymalis. 
The lachrymal groove in the articulated skull is converted into a canal {canalis 
lacrimalis) by the lachrymal bone and lachrymal process of the inferior turbin- 
ated; it is directed downward, and a little backward and outward, is about the 
diameter of a goose-quill, slightly narrower in the middle than at either extremity, 
and terminates below in the inferior meatus. It lodges the nasal duct. 
Alveolar Process {processus alveolaris).-The alveolar process is the thickest 
and most spongy part of the bone, broader behind than in front, and excavated 
into deep cavities for the reception of the teeth {alveoli dentales). These cavities 
are eight in number, and vary in size and depth according to the teeth they con- 
tain. That for the canine tooth is the deepest; those for the molars are the 
widest, and subdivided into minor cavities by septa; those for the incisors are 
single, but deep and narrow. The limbus alveolaris is the broad inferior margin 
of the alveolar process. On the anterior surface are five projections correspond- 
1 The number of teeth whose fangs are in relation to the floor of the antrum is variable. The antrum " may 
extend so as to be in relation to all the teeth of the true maxilla, from the canine to the dens sapiential." (See 
Mr. Salter on Abscess of the Antrum, in a System of Surgery, edited by T. Holmes, 2d ed., vol. iv. p. 356). THE SKELETON 
110 
ing to the five anterior alveoli. They are called juga alveolaria. The cavities 
for the teeth are separated by septa interalveolaria. The Buccinator muscle arises 
from the outer surface of this process as far forward as the first molar tooth. 
Palate Process (processus palatinus).-The palate process, thick and strong, 
projects horizontally inward from the inner surface of the bone. It is much thicker 
in front than behind, and 
forms a considerable part 
of the floor of the nostril 
and the roof of the mouth. 
Its inferior surface (Fig. 
72) is concave, rough and 
uneven, contains numer- 
ous little cavities for the 
glands of the mucous 
membrane, and forms 
part of the roof of the 
mouth. This surface is 
perforated by numerous 
foramina for the passage 
of the nutrient vessels, 
channelled at the back 
part of its alveolar bor- 
der by a longitudinal 
groove,sometimes a canal, 
for the transmission of 
the posterior palatine 
vessels, and the great pos- 
terior palatine nerve from 
Meckel's ganglion, and 
presents little depressions 
for the lodgement of the palatine glands. When the two superior maxilhe 
bones are articulated together, a large orifice may be seen in the middle 
line, immediately behind the incisor teeth. This is the anterior palatine fossa 
(foramen incisivum). On examining the bottom of this fossa four canals are 
seen: two branch off laterally to the right and left nasal fosste, and two, one in 
front and one behind, lie in the middle line. The former pair of these openings 
are named the incisor foramina or foramina of Stenson; they are the openings of 
the forking incisor canal (canalis incisivus), through which pass the anterior or 
terminal branches of the descending or posterior palatine arteries, which ascend 
from the mouth to the nasal fossae, and they contain the remains of Jacobson's 
organ. The canals in the middle line are termed the foramina of Scarpa, and 
transmit the naso-palatine nerves, the left passing through the anterior, and the 
right through the posterior, canal. Occasionally in adults' skulls, often in chil- 
dren's skulls, on the palatal surface of the process a delicate linear suture may 
sometimes be seen extending from the anterior palatine fossa to the interval 
between the lateral incisor and the canine tooth. This marks out the inter- 
maxillary or pre-maxillary bones or the incisive bone (os incisivum) on each side. 
It is the portion of the upper jaw which is in front of the anterior palatine 
foramen, and which in some animals exists permanently as a separate piece. 
It includes the whole thickness of the alveolus, the corresponding part of the floor 
of the nose, and the anterior nasal spine, and contains the sockets of the incisor 
teeth. The pre-maxillary bone has a separate centre of ossification and develops 
in association with the vertical plate of the ethmoid and the vomer. The incisive 
bones, which are always present in the foetus, usually join the rest of the bone 
Anterior palatine canal. 
Foramen of Stenson. 
Foramen of Scarpa. 
Palate process of 
maxillary bone. 
Horizontal plate' 
of palate bone. 
Posterior palatine canal. 
Accessory palatine foramen. 
Fig. 72.-The palate and alveolar arch. THE SUPERIOR MAXILLARY BONES 
111 
early in development, more or less well-marked sutures (sutura incisiva) indi- 
cating the lines of union. In double hare-lip the incisive bones covered by the 
median part of the lip are frequently not joined to the palate processes of the 
superior maxillary bones, but are fixed to the nasal septum. Albrecht maintains 
that instead of two intermaxillary seg- 
ments or incisive bones, each carrying 
two incisor teeth, there are originally 
four, each carrying the rudiment of 
one tooth and each of a triangular 
shape, the apices approaching at the 
anterior palatine canal. The seg- 
ments are separated by five sutures. 
The maxilla is called the exo-gnathion, 
each mesial segment is called an endo- 
gnathion, and each lateral segment 
a meso-gnathion. In hare-lip the cleft 
may be purely in the soft parts, but may pass into the nostril, the alveolar portion 
of the maxilla, or through the palate bone (cleft palate). In hare-lip with cleft 
palate (alveolar hare-lip') Kolliker believes that the cleft is between the maxilla and 
the intermaxillary bone; that is, between the exo-gnathion and the meso-gnathion. 
Albrecht is of the opinion that the cleft is between the endo-gnathion and the meso- 
gnathion. In some cases of double hare-lip the pre-maxillary segment contains the 
germs of four incisors, and in such a case the cleft must be between the exo- 
gnathion and the meso-gnathion. In other cases it contains but two, and in such 
a case the cleft must be as indicated by Albrecht, as Fergusson's explanation is 
not in accordance with our knowledge of development. Fergusson believed that 
if the germs of four incisors are not present the missing ones were lost in the gap. 
The upper surface oi the palate process is concave from side to side, smooth, and 
forms part of the floor of the nose. It presents the upper orifices of the foramina of 
ENDOGNATHION. 
ENDOGNATHION 
SUTURE 
EN DO-MESOGNATHION 
SUTURE 
MESOGNATHION 
EXOGNATHION 
ENDO-EXOGNATHION 
SUTURE 
MESO-EXOGNATHION 
SUTURE 
Fig. 73.-The pre-maxilla and its sutures. (Albrecht.) 
Fig. 74.-Kolliker's theory of alveolar hare-lip. 
(Poirier and Charpy.) 
Fig. 75.-Alveolar hare-lip according to the theory of 
Albrecht. (Poirier and Charpy.) 
Stenson and Scarpa, the former being on each side of the middle line, the latter 
being situated in the intermaxillary suture, and therefore not visible unless the two 
bones are placed in apposition. The outer border of the palate process is incorpor- 
ated with the rest of the bone. The inner border is thicker in front than behind, and 
is raised above into a ridge, the nasal crest {crista nasalis), which, with the corre- 
sponding ridge in the opposite bone, forms a groove for the reception of the vomer. 
In front this crest rises to a considerable height, and this portion is named the incisor 
crest. The anterior margin is bounded by the thin, concave border of the opening 
of the nose, prolonged forward internally into a sharp process, forming, with a 
similar process of the opposite bone, the anterior nasal spine {spina nasalis anterior). 
The posterior border is serrated for articulation with the horizontal plate of the 
palate bone. THE SKELETON 
112 
Development.-This bone commences to ossify at a very early period, and 
ossification proceeds in it with great rapidity, so that it is difficult to ascertain with 
certainty its precise number of centres. It appears, however, probable that it is 
ossified from four centres, which are deposited in membrane. 1. One which forms 
that portion of the body of the bone which lies internal 
to the infraorbital canal, including the floor of the orbit, 
the outer wall of the nasal fossa, and the nasal process. 
2. A second which gives origin to that portion of the 
bone which lies external to the infraorbital canal and the 
malar process. 3. A third from which is developed the 
palatine process posterior to Stenson's canal and the ad- 
joining part of the nasal wall. 4. And a fourth for the 
front part of the alveolus which carries the incisor teeth 
and corresponds to the pre-maxillary bone of the lower 
animals. These centres appear about the eighth week, 
and by the tenth week the three first-named centres 
have become fused together and the bone consists of two 
portions, one the maxilla proper, and the other the pre- 
maxillary portion. The suture between these two por- 
tions on the palate persists till middle life, but is not to 
be seen on the facial surface. This is believed by Cal- 
lender to be due to the fact that the front wall of the 
sockets of the incisive teeth is not formed by the pre- 
maxillary bone, but by an outgrowth from the facial part 
of the superior maxilla. The antrum appears as a shal- 
low groove on the inner surface of the bone at an earlier 
period than any of the other nasal sinuses, its development commencing about 
the fourth month of foetal life. The sockets for the teeth are formed by the 
growing downward of two plates from the dental groove, which subsequently 
becomes divided by partitions jutting across from the one to the other. If the 
two palate processes fail to unite partially or completely, a partial or complete 
cleft palate results. 
Articulations.-With nine bones: two of the cranium, the frontal and ethmoid, 
and seven of the face-viz., the nasal, malar, lachrymal, inferior turbinated, palate, 
vomer, and its fellow of the opposite side. Sometimes it articulates with the orbital 
plate of the sphenoid, and sometimes with its external pterygoid plate. 
Attachment of Muscles.-To twelve: the Orbicularis palpebrarum, Obliquus 
oculi inferior, Levator labii superioris aheque nasi, Levator labii superioris pro- 
prius, Levator anguli oris, Compressor nasi, Depressor ahe nasi, Dilatator naris 
posterior, Masseter, Buccinator, Internal pterygoid, and Orbicularis oris. 
Anterior Surface. 
Inferior Surface. 
Fig. 76. - Development of 
superior maxillary bone. At 
birth. 
CHANGES PRODUCED IN THE UPPER JAW BY AGE. 
At birth and during infancy the diameter of the bone is greater in an antero-posterior than 
in a vertical direction. Its nasal process is long, its orbital surface large, and its tuberosity 
well marked. In the adult the vertical diameter is the greater, owing to the development of 
the alveolar process and the increase in size of the antrum. In old age the bone approaches 
again in character tQ the infantile condition: its height is diminished, and after the loss of the 
teeth the alveolar process is absorbed, and the lower part of the bone contracted and diminished 
in thickness. 
The Lachrymal Bone (Os Lacrimale). 
The lachrymal (lachryma, a tear) is the smallest and most fragile bone of 
the face. There are two lachrymal bones. They are situated at the front part 
of the inner wall of the orbit (Fig. 67), and resemble somewhat in form, thinness, THE MALAR BONE 
113 
and size a finger-nail; hence they are termed the ossa unguis. Each bone presents 
for examination two surfaces and four borders. 
Surfaces. External Surface.-The external or orbital surface (Fig. 77) is divided 
by a vertical ridge, the lachrymal crest {crista lacrimalis posterior), into two parts. 
The portion of bone in front of this ridge, the lachrymal sulcus {sulcus lacrimalis), 
presents a smooth, concave, longitudinal groove, the free margin of which unites 
with the nasal process of the superior maxillary bone, completing the lachrymal 
groove. The upper part of this groove {fossa sacci lacrimalis) 
lodges the lachrymal sac; the lower part {sulcus lacrimalis) 
lodges the nasal duct. The portion of bone behind the ridge 
is smooth, slightly concave, and forms part of the inner wall 
of the orbit. The ridge, with a part of the orbital surface 
immediately behind it, affords attachment to the Tensor tarsi 
muscle: it terminates below in a small, hook-like projection, 
the hamular process {hamulus lacrimalis), which articulates 
with the lachrymal tubercle of the superior maxillary bone, 
and completes the upper orifice of the lachrymal groove. 
It sometimes exists as a separate piece, which is then called 
the lesser lachrymal bone. 
Internal Surface.-The internal or nasal surface presents 
a depressed furrow, corresponding to the ridge on its outer 
surface. The surface of bone in front of this forms part of 
the middle meatus, and that behind it articulates with the ethmoid bone, fill- 
ing in the anterior ethmoidal cells. 
Borders.-Of the four borders, the anterior is the longest, and articulates with 
the nasal process of the superior maxillary bone. The posterior, thin and uneven, 
articulates with the os planum of the ethmoid. The superior, the shortest and 
thickest, articulates with the internal angular process of the frontal bone. The 
inferior is divided by the lower edge of the vertical crest into two parts; the poste- 
rior part articulates with the orbital plate of the superior maxillary bone; the 
anterior portion is prolonged downward into a pointed process, which articulates 
with the lachrymal process of the inferior turbinated bone and assists in the forma- 
tion of the lachrymal groove. 
Development.-By a single centre, which makes its appearance soon after ossifi- 
cation of the vertebrae has commenced. 
Articulations.-With four bones: two of the cranium, the frontal and ethmoid, 
and two of the face, the superior maxillary and the inferior turbinated. 
Attachment of Muscles.-To one muscle, the Tensor tarsi. 
With frontal. 
Fig. 77. - Left lachry- 
mal bone. External sur- 
face. (Slightly enlarged.) 
The Malar Bone (Os Zygomaticum). 
The name malar is derived from mala, the cheek. The malar or yoke bone is 
also called the cheek bone. There are two malar bones. Each is a small, quad- 
rangular bone, situated at the upper and outer part of the face. They form 
the prominence of the cheek, part of the outer wall and floor of the orbit, and 
part of the temporal and zygomatic fossae (Tig. 78). Each bone presents for 
examination an external and an internal surface; four processes, the frontal, 
orbital, maxillary, and zygomatic processes; and four borders. 
Surfaces. External or Malar Surface {fades malar is).-The external surface 
(Fig. 79) is smooth, convex, perforated near its centre by a small aperture, the 
malar foramen {foramen zygomaticofadale), for the passage of nerves and vessels 
from the orbit. The malar surface is covered by the Orbicularis palpebrarum 
muscle, and affords attachment to the Zygomaticus major and minor muscles. 114 
THE SKELETON 
Internal or Temporal Surface (facies temporalis).-The internal surface (Fig. 80), 
directed backward and inward, is concave, presenting internally a rough, 
triangular surface, for articulation with the superior maxillary bone; and exter- 
nally, a smooth concave surface, which above forms the anterior boundary of 
Zygoma- 
tic proc. 
Fig. 78.-Malar bone in situ. 
the temporal fossa, and below, where it is wider, forms part of the zygomatic 
fossa. This surface presents, a little above its centre, the aperture of a malar 
canal (foramen zygomaticotemporale), and affords attachment to a portion of the 
Masseter muscle at its lower part. 
With frontal. 
Bristles passed 
through temporo- 
malar canals. 
Fio. 79.-Left malar bone. Outer surface. 
Fig. 80.-Left malar bone. Inner surface. 
Processes. Frontal Process (processus frontosphenoidal is).-Of the four 
processes, the frontal is thick and serrated, and articulates with the external 
angular process of the frontal bone. To its orbital margin is attached the 
external tarsal ligament. 
Orbital Process.-The orbital process is a thick and strong plate, which projects 
backward from the orbital margin of the bone. Its supero-internal surface (facies THE PALATE BONE 
115 
orbital is), smooth and concave, forms, by its junction with the orbital surface of the 
superior maxillary bone and with the great wing of the sphenoid, part of the floor 
and outer wall of the orbit. Its injero-external surface, smooth and convex, forms part 
of the zygomatic and temporal fossae. Its anterior margin is smooth and rounded, 
forming part of the circumference of the orbit. Its superior margin, rough and 
directed horizontally, articulates with the frontal bone behind the external angular 
process. Its posterior margin is rough and serrated for articulation with the 
sphenoid; internally it is also serrated for articulation with the orbital surface of 
the superior maxillary. At the angle of junction of the sphenoidal and maxillary 
portions a short, rounded, non-articular margin is generally seen; this forms the 
anterior boundary of the spheno-maxillary fissure: occasionally no such non- 
articular margin exists, the fissure being completed by the direct junction of the 
maxillary and sphenoid bones or by the interposition of a small Wormian bone in 
the angular interval between them. On the upper surface of the orbital process 
are seen a single or double temporo-malar foramen rf or amen zygomaticoorbitale), 
the entrance of the temporo-malar canal. This canal may be bifurcated, or 
there may be two canals from the beginning; one of these usually opens on the 
posterior surface, the other (occasionally two) on the facial surface: they transmit 
filaments (temporo-malar) of the orbital branch of the superior maxillary nerve. 
Maxillary Process.-The maxillary process is a rough, triangular surface which 
articulates with the malar process of the superior maxillary bone. 
Zygomatic Process (processus temporalis).-The zygomatic process, long, narrow, 
and serrated, articulates with the zygomatic process of the temporal bone. 
Borders.-Of the four borders, the antero-superior or orbital border is smooth, 
arched, and forms a considerable part of the circumference of the orbit. The 
antero-injerior or maxillary border is rough, and bevelled at the expense of its 
inner table, to articulate with the superior maxillary bone; affording attachment 
by its margin to the Levator labii superioris proprius, just at its point of junction 
with the superior maxillary. The postero-superior or temporal border, curved like 
an italic letter j, is continuous above with the commencement of the temporal 
ridge; below, with the upper border of the zygomatic arch: it affords attachment 
to the temporal fascia. The postero-inferior or zygomatic border is continuous 
with the lower border of the zygomatic arch, affording attachment by its rough 
edge to the Masseter muscle. 
Development.-The malar bone ossifies generally from three centres, which 
appear about the eighth week-one for the zygomatic and two for the orbital 
portion-and fuse about the fifth month of festal life. The bone is sometimes, 
after birth, seen to be divided by a horizontal suture into an upper and larger 
and a lower and smaller division. In some quadrumana the malar bone consists 
of two parts, an orbital and a malar, which are ossified by separate centres. 
Articulations.-With four bones: three of the cranium, frontal, sphenoid, and 
temporal; and one of the face, the superior maxillary. 
Attachment of Muscles.-To four: the Levator labii superioris proprius, 
Zygomaticus major and minor, and Masseter. 
The Palate Bone (Os Palatinum) 
The palate bones (palatum, the palate) are situated at the back part of the 
nasal fossae: they are wedged in between the superior maxillary bones and the 
pterygoid processes of the sphenoid (Fig. 81). Each bone assists in the formation 
of three cavities: the floor and outer wall of the nose, the roof of the mouth, and 
the floor of the orbit, and enters into the formation of two fossae, the spheno- 
maxillary (fossa pterygopalatina) and pterygoid fossae (fossa pterygoidea); and one 
fissure, the spheno-maxillary fissure (fissura orbitalis inferior). In form the palate 116 
THE SKELETON 
bone somewhat resembles the letter L, and may be divided into an inferior or 
horizontal plate and a superior or vertical plate. 
Orbital process., 
Nasal process. 
'Sup. turbinated crest. 
Spheno-palatine for.. 
Sphenoidal process.-. 
Sup. turbinated crest.'' 
Inf. turbinated crest. 
Inf. turbinated crest., 
■Ant. nasal spine. 
Fig. 81.-Palate bone in situ. 
The Horizontal Plate of the Palate Bone (Pars Horizontalis) (Fig. 83). 
The horizontal plate is of a quadrilateral form, and presents two surfaces and 
four borders. 
Surfaces. Superior Surface {facies nasalis).-The superior or nasal surface, 
concave from side to side, forms the back part of the floor of the nasal cavity. 
Inferior Surface {facies palatind).-The inferior or palatine surface, slightly 
concave and rough, forms the back part of the hard palate. At its posterior part 
may be seen a transverse ridge, more or less marked, for the attachment of part 
of the aponeurosis of the Tensor palati muscle. At the outer extremity of this 
ridge is a deep groove, the pterygopalatine groove {sulcus pterygopalatinus), 
converted into a canal by its articulation with the tuberosity of the superior 
maxillary bone, and forming the lower end of the posterior palatine canal {canalis 
pterygopalatinus), the opening of which is called the great palatine foramen {fora- 
men palatinum majus). Near this groove the orifices {foramina palatina minora) 
of one or two small canals, accessory posterior palatine canals {canales palatini) 
may be seen. Through the posterior palatine canal emerge the descending 
palatine artery and the great posterior palatine nerve. 
Borders.-The anterior border is serrated, bevelled at the expense of its inferior 
surface, and articulates with the palate process of the superior maxillary bone. 
The posterior border is concave, free, and serves for the attachment of the soft 
palate. Its inner extremity is sharp and pointed, and, when united with the 
opposite bone, forms a projecting process, the posterior nasal or palatine spine 
{spina nasalis posterior), for the attachment of the Azygos uvulae muscle. The 
external border is united with the lower part of the perpendicular plate almost 
at right angles. The internal border, the thickest, is serrated for articulation with 
its fellow of the opposite side; its superior edge is raised into a ridge, which, united 
with the opposite bone, forms a crest {crista nasalis) into which the vomer is 
received. THE PALATE BONE 
117 
The Vertical or Perpendicular Plate of the Palate Bone (Pars Perpendicularis). 
The vertical or perpendicular plate (Figs. 82 and 83) is thin, of an oblong 
form, and directed upward and a little inward. It presents two surfaces, an 
external and an internal, and four borders. 
Surfaces. Internal, Medial, or Nasal Surface (jacies nasalis).-The internal sur- 
face presents at its lower part a broad, shallow depression, which forms part of 
the inferior meatus of the nose. 
Immediately above this is a 
well-marked horizontal ridge, 
the inferior turbinated crest 
(crista conchalis), for articula- 
tion with the inferior turbin- 
ated bone; above this, a second 
broad, shallow depression, 
which forms part of the mid- 
dle meatus, surmounted above 
by a horizontal ridge less 
prominent than the inferior, 
the superior turbinated crest 
(crista ethmoidalis), for articu- 
lation with the middle turbin- 
ated bone. Above the superior 
turbinated crest is a narrow, 
horizontal groove, which forms 
part of the superior meatus. 
External, Lateral, or Maxillary 
Surface (jacies maxillaris}.- 
The external surface is rough and irregular throughout the greater part of its extent, 
for articulation with the inner surface of the superior maxillary bone, its upper 
and back part being smooth where it enters 
into the formation of the spheno-maxillary 
fossa; it is also smooth in front, where it 
covers the orifice of the antrum. Toward 
the back part of this surface is a deep 
groove, the pterygo-palatine groove, converted 
into a canal, the posterior palatine canal, by 
its articulation with the superior maxillary 
bone. It transmits the posterior or descend- 
ing palatine vessels and the great posterior 
palatine nerve from Meckel's ganglion. 
Borders. Anterior Border (Fig. 82).-The 
anterior border is thin, irregular, and pre- 
sents opposite the inferior turbinated crest 
a pointed, projecting lamina, the maxillary 
process (processus maxillaris), which is di- 
rected forward, and closes in the lower and 
back part of the opening of the antrum. 
Posterior Border.-The posterior border 
(Fig. 83) presents a deep groove, the edges 
of which are serrated for articulation with 
the pterygoid process of the sphenoid. At the lower part of this border is seen a 
pyramidal process of bone, the pterygoid process or tuberosity of the palate (processus 
pyramidalis), which is received into the angular interval between the two pterygoid 
Orbital process. 
Orbital surface. 
Maxillary surface. 
Superior meatus. 
Spheno-palatine foramen. 
Vertical Plate. 
Maxillary 
' process. 
Horizontal Plate. 
Fig. 82.-Left palate bone. Internal view. (Enlarged.) 
Orbital process. 
'Sphenoidal palatine 
foramen. 
Vertical Plate. 
Posterior 
palatine' 
canal. 
Sphenoidal process. 
Articular portion. 
■ Non-articular portion. 
External Surface. 
"azygos uvula.i 
Horizontal 
Plate. 
' Posterior 
nasal spine. 
Fig. 83.-Left palate bone. Posterior view. 
(Enlarged.) 118 
THE SKELETON 
plates of the sphenoid at their inferior extremity. This process presents at its back 
part a median groove and two lateral surfaces. The groove is smooth, and forms 
part of the pterygoid fossa, affording attachment to the Internal pterygoid muscle; 
whilst the lateral surfaces are rough and uneven, for articulation with the anterior 
border of each pterygoid plate. A few fibres of the Superior constrictor arise from 
the tuberosity of the palate bone. The base of this process, continuous with the 
horizontal portion of the bone, presents the aperture of the accessory descending 
palatine canals, through which pass the two smaller descending branches of 
Meckel's ganglion ; whilst its outer surface is rough for articulation with the 
inner surface of the body of the superior maxillary bone. 
Superior Border.-The superior border of the vertical plate presents two well- 
marked processes separated by an intervening notch or foramen. The anterior, 
or larger, is called the orbital process; the posterior, the sphenoidal process. 
Processes. Orbital Process (processus orbital is).-The orbital process, directed 
upward and outward, is placed on a higher level than the sphenoidal. It presents 
five surfaces, which enclose a hollow cellular cavity, and is connected with the per- 
pendicular plate by a narrow, constricted neck. Of these five surfaces, three are 
articular, two non-articular or free surfaces. The three articular are the anterior or 
maxillary surface, which is directed forward, outward, and downward, is of an 
oblong form, and rough for articulation with the superior maxillary bone. The pos- 
terior or sphenoidal surface is directed backward, upward, and inward. It ordinarily 
presents a small, open cell, the orbital sinus (sinus orbitalis), which communicates 
with the sphenoidal cells, and the margins of which are serrated for articulation with 
the vertical partof the sphenoidal turbinated bone. "The orbital may communicate 
not only with the sphenoidal sinus and the ethmoidal cells, but, in rare instances, 
with the maxillary antrum."1 The internal or ethmoidal surface is directed inward, 
upward, and forward, and articulates with the lateral mass of the ethmoid bone. 
In some cases the cellular cavity opens on the internal surface of the bone; it then 
communicates with the posterior ethmoidal cells. More rarely it opens on both 
surfaces, and then communicates with both the posterior ethmoidal and the 
sphenoidal cells. The non-articular or free surfaces are the superior or orbital 
surface, directed upward and outward, of triangular form, concave, smooth, and 
forming the back part of the floor of the orbit; and the external or zygomatic surface, 
directed outward, backward, and downward, of an oblong form, smooth, lying in 
the spheno-maxillary fossa, and looking into the zygomatic fossa. The latter 
surface is separated from the orbital by a smooth, rounded border, which enters 
into the formation of the spheno-maxillary fissure. 
Sphenoidal Process (processus sphenoidalis).-The sphenoidal process of the 
palate bone is a thin, compressed plate, much smaller than the orbital, and 
directed upward and inward. It presents three surfaces and two borders. The 
superior surface, the smallest of the three, articulates with the under surface of 
the sphenoidal turbinated bone; it presents a groove, which contributes to the 
formation of the pterygo-palatine canal. The internal surface is concave, and 
forms part of the outer wall of the nasal fossa. The external stirface is divided 
into an articular and a non-articular portion: the former is rough, for articulation 
with the inner surface of the internal pterygoid plate of the sphenoid; the latter is 
smooth, and forms part of the spheno-maxillary fossa. The anterior border forms 
the posterior boundary of the spheno-palatine notch. The posterior border, 
serrated at the expense of the outer table, articulates with the inner surface of 
the internal pterygoid plate. 
The orbital and sphenoidal processes are separated from one another by a deep 
notch, the spheno-palatine notch (incisura s pheno palatinum), which is converted 
1 Dr. D. Kerfoot Shute, in the Reference Handbook of the Medical Sciences. THE INFERIOR TURBINATED BONE 
119 
into a foramen, the spheno-palatine foramen (foramen sphenopalatinum), by articu- 
lation with the under surface of the body of the sphenoid bone. Sometimes the 
two processes are united above, and form between them a complete foramen (Figs. 
82 and 83), or the notch is crossed by one or more spiculae of bone, so as to form 
two or more foramina. In the articulated skull this foramen is seen to pass from 
the spheno-maxillary fossa into the back part of the superior meatus. It trans- 
mits the spheno-palatine vessels and the superior nasal and naso-palatine nerves. 
Development.-From a single centre, which makes its appearance about the 
second month at the angle of junction of the two plates of the bone. From this 
point ossification spreads inward to the horizontal plate, downward into the 
tuberosity, and upward into the vertical plate. In the foetus the horizontal plate 
is much larger than the vertical, and even after it is fully ossified the whole bone 
is at first remarkable for its shortness. 
Articulations.-With six bones: the sphenoid, ethmoid, superior maxillary, 
inferior turbinated, vomer, and opposite palate. 
Attachment of Muscles.--To four: the Tensor palati, Azygos uvulae, Internal 
pterygoid, and Superior constrictor of the pharynx. 
The Inferior Turbinated Bone (Concha Nasalis Inferior). 
The inferior turbinal or turbinated bones (turbo, a whirl) are situated one on 
each side of the outer wall of the nasal fossae. Each inferior turbinated bone 
(concha nasalis inferior) consists of a layer of thin, spongy bone, curled upon 
SU PERIOR 
MEATUS 
MIDDLE 
MEATUS 
APERTURE OF 
SPHENOIDAL SINUS 
SPHENO- 
PALATINE 
FORAMEN 
NASO-PHARYNGEAL 
MEATUS 
Fig. 84.-Nasal cavity, right lateral wall, from the left. (Spalteholz.) 
itself like a scroll-hence its name "turbinated"-and extends horizontally 
along the outer wall of the nasal fossa, immediately below the orifice of the 
antrum (Fig. 84). Each bone presents two surfaces, two borders, and two 
extremities. 120 
THE SKELETON 
Surfaces.-The internasal surface (Fig. 85) is convex, perforated by numerous 
apertures, and traversed by longitudinal grooves and canals for the lodgement 
of arteries and veins. In the recent state it is covered by the lining membrane of 
the nose. The external surface is concave (Fig. 86), and forms part of the inferior 
meatus. 
Fig. 85.-Right inferior turbinated bone. Internal 
surface. 
Fig. 86.-Right inferior turbinated bone. 
External surface. 
Borders.-Its upper border is thin, irregular, and connected to various bones 
along the outer wall of the nose. It may be divided into three portions: of these, 
the anterior articulates with the inferior turbinated crest of the superior maxillary 
bone; the posterior with the inferior turbinated crest of the palate bone; the middle 
portion of the superior border presents three well-marked processes, which vary 
much in their size and form. Of these, the anterior and smallest is situated at 
the junction of the anterior fourth with the posterior three-fourths of the bone: 
it is small and pointed, and is called the lachrymal process (processus lacrimalis); 
it articulates by its apex with the anterior inferior angle of the lachrymal bone, 
and by its margins with the groove on the back of the nasal process of the supe- 
rior maxillary, and thus assists in forming the canal for the nasal duct. At the 
junction of the two middle fourths of the bone, but encroaching on its posterior 
fourth, a broad, thin plate, the ethmoidal process (processus ethmoidalis), ascends 
to join the unciform process of the ethmoid; from the lower border of this pro- 
cess a thin lamina of bone curves downward and outward, hooking over the 
lower edge of the orifice of the antrum, which it narrows below: it is called the 
maxillary process (processus maxiliar is), and fixes the bone firmly to the outer wall 
of the nasal fossa. The injerior border is free and thick, more especially in the 
middle of the bone. Bone extremities are more or less narrow and pointed, the 
posterior being the more tapering. If the bone is held so that its outer concave 
surface is directed backward (i. e., toward the holder), and its superior border, from 
which the lachrymal and ethmoidal processes project, upward, the lachrymal pro- 
cess will be directed to the side to which the bone belongs.1 In a study of 1000 speci- 
mens, Howard A. Lothrop2 did not discover cells in the inferior turbinated bone. 
Development.-By a single centre, which makes its appearance about the 
middle of foetal life. 
Articulations.-With four bones: one of the cranium, the ethmoid, and three 
of the face, the superior maxillary, lachrymal, and palate. 
No muscles are attached to this bone. 
The Vomer (Ploughshare Bone) 
The vomer (vomer, a ploughshare) is a single bone, situated vertically at the 
back part of the nasal fossae, forming part of the septum of the nose (Fig. 87). 
It is thin, somewhat like a ploughshare in form; but it varies in different indi- 
viduals, being frequently bent to one or the other side; it presents for examination 
two surfaces and four borders. 
1 If the lachrymal process is broken off, as is often the case, the side to which the bone belongs may be known 
by recollecting that the maxillary process is nearer the back than the front of the bone. 
2 Annals of Surgery, May, 1903. THE VOMER 
121 
Surfaces.-The lateral surfaces are smooth, marked by small furrows for the 
lodgement of blood-vessels, and by a groove on each side, sometimes a canal, the 
naso-palatine groove or canal, which runs obliquely downward and forward to the 
intermaxillary suture; it transmits the naso-palatine nerve. 
Frontal sinuses. 
Crista galli. 
Sphenoidal sinuses. 
Perpendicular 
plate of eth- 
moid. 
Space for triangular 
cartilage of septum. 
Vomer. 
'Rostrum of sphenoid. 
Palate process. 
Int. pterygoid plate. 
Fig. 87.-Vomer in situ. 
Borders.-The superior border, the thickest, presents a deep groove, bounded 
on each side by a horizontal projecting leaf of bone; these leaves are the alae 
(alee vomeris}. The groove formed by the ahe receives the rostrum of the 
sphenoid, while the alae are overlapped and retained by the vaginal processes, which 
project from the under surface of the body of the sphenoid at the base of the 
pterygoid processes. At the front 
of the groove a fissure is left for 
the transmission of blood-vessels 
to the substance of the bone. The 
inferior border, the longest, is 
broad and uneven in front, where 
it articulates with the two supe- 
rior maxillary bones; thin and 
sharp behind, where it joins with 
the palate bones. The upper 
half of the anterior border usually 
consists of two laminae of bone, 
in the groove between which is 
received the perpendicular plate 
of the ethmoid; the lower half, 
also separated into two lamellae, receives between them the lower margin of the 
septal cartilage of the nose. The posterior border is free, concave, and separates 
the nasal fossae behind. It is thick and bifid above, thin below. 
The surfaces of the vomer are covered by mucous membrane, which is inti- 
mately connected with the periosteum, with the intervention of very little, if any, 
Alee. 
With sup. maxill. bones and palate. 
Fig. 88.-The vomer. 122 
THE SKELETON 
submucous connective tissue. Hence polypi are rarely found growing from this 
surface, though they frequently grow from the outer wall of the nasal fosste, 
where the submucous tissue is abundant. 
Development.-The vomer at an early period consists of two laminae, separated 
by a very considerable interval, and enclosing between them a plate of cartilage, 
the vomerine cartilage, which is prolonged forward to form the remainder of the 
septum. Ossification commences in the membrane at the postero-inferior part of 
this cartilage by two centres, one on each side of the middle line, which extend 
to form the two laminae. They begin to coalesce at the lower part, but their 
union is not complete until after puberty. 
Articulations.-With^'a; bones: two of the cranium, the sphenoid and ethmoid; 
and four of the face, the superior maxillary and the two palate bones; and with 
the cartilage of the septum. 
The vomer has no muscles attached to it. 
The Maxillary Bone, Inferior Maxilla, Mandible or Lower Jaw (Mandibula). 
The mandible, the largest and strongest bone of the face, serves for the 
reception of the lower teeth. It consists of a curved, horizontal portion, the 
body, and two perpendicular portions, the rami, which join the back part of 
the body nearly at right angles. 
The Horizontal Portion or Body of the Mandible (Corpus Mandibulae). 
The horizontal portion or body (Fig. 89) is convex in its general outline, and 
curved somewhat like a horseshoe. It presents for examination two surfaces and 
two borders. 
Coronoid process. 
Condyle. 
MASSETER 
Ramus. 
Body 
Mental 
process. 
-Angle. 
Fig. 89.-The mandible. Outer surface. Side view. 
Groove for facial artery. 
Surfaces. External Surface.-The external surface is convex from side to side, 
concave from above downward. In the median line is a vertical ridge, the symphy- 
sis, which extends from the upper to the lower border of the bone, and indicates 
the point of junction of the two pieces of which the bone is composed at an early 
period of life. The lower part of the ridge terminates in a prominent triangular 
eminence, the mental process or protuberance (protuberantia mentalis). This emi- 
nence is rounded below, and often presents a median depression separating two 
processes, the mental tubercles (tubera mentalia). It forms the chin, a feature 
peculiar to the human skull. On either side of the symphysis, just below the THE MAXILLARY BONE 
123 
cavities for the incisor teeth, is a depression, the incisive or incisor fossa, for the 
attachment of the Levator menti (or Levator labii inferioris); more externally is 
attached a portion of the Orbicularis oris (accessorii orbicularis injerioris), and, 
still more externally, a foramen, the mental foramen (foramen mentale), for the 
passage of the mental vessels and nerve. This foramen is placed just below the 
interval between the two bicuspid teeth. Running outward from the base of the 
mental process on each side is a ridge, the external oblique line (linea obliqua). 
The ridge is at first nearly horizontal, but afterward inclines upward and back- 
ward, and is continuous with the anterior border of the ramus: it affords attach- 
ment to the Depressor labii inferioris and Depressor anguli oris; below it the 
Platysma myoides is attached. 
Internal Surface.-The internal surface (Fig. 90) is concave from side to side, 
convex from above downward. In the middle line is an indistinct linear depres- 
Pterygoid 
depression. 
TEM PORALj 
GENlO-MVO-t LOSS 
GtNIO-HYOlOEUB. 
Mylo-hyoid ridge. 
Body. 
Fig. 90.-The mandible. Inner surface. Side view. 
sion, corresponding to the symphysis externally; on either side of this depression, 
just below its centre, are four prominent tubercles, placed in pairs, two above and 
two below; they are called the genial tubercles or mental spines (spina mentales), and 
afford attachment, the upper pair to the Genio-hyo-glossi, the lower pair to the 
Genio-hyoidei, muscles. Sometimes the tubercles on each side are blended into 
one; at others they all unite into an irregular eminence; or, again, nothing but an 
irregularity may be seen on the surface of the bone at this part. On either side of 
the genial tubercles is an oval depression, the sublingual fossa (fovea sublinguc hs}, 
for lodging the sublingual gland; and beneath the fossa a rough depression on 
each side which gives attachment to the anterior belly of the Digastric muscle, 
the digastric fossa (fossa digastrica). At the back part of the sublingual fossa the 
internal oblique line or mylo-hyoid ridge (tinea mylohyoidea) commences; it is at 
first faintly marked, but becomes more distinct as it passes upward and outward, 
and is especially prominent opposite the last two molar teeth; it affords attach- 
ment throughout its whole extent to the Mylo-hyoid muscle; the Superior con- 
strictor of the pharynx with the pterygo-maxillary ligament being attached above 
its posterior extremity, near the alveolar margin. The portion of the bone above 
this ridge is smooth and covered by the mucous membrane of the mouth; the 
portion below presents an oblong depression, the submaxillary fossa (fovea sub- 
max illar is), wider behind than in front, for the lodgement of the submaxillary THE SKELETON 
124 
gland. The external oblique line and the internal or mylo-hyoidean line divide 
the body of the bone into a superior or alveolar and an inferior or basilar portion. 
Borders.-The superior or alveolar portion of the body (pars alveolaris) has 
above a narrow border which is wider and the margins of which are thicker 
behind than in front. Its narrow margin is called the limbus alveolaris. It is 
hollowed into numerous cavities (alveoli dentales), for the reception of the teeth; 
these cavities are sixteen in number, and vary in depth and size according to the 
teeth which they contain. The cavities are separated from one another by septa 
interalveolaria. The juga alveolaria are prominences on the outer surface over the 
three front alveoli. To the outer side of the alveolar border the Buccinator muscle 
is attached upon the buccinator crest (crista buccinatoria) as far forward as the 
first molar tooth. The inferior or basilar portion (basis mandibuloe) is rounded, 
longer than the superior, and thicker in front than behind; it presents a shallow 
groove, just where the body joins the ramus, over which the facial artery turns. 
The Perpendicular Portions or Rami of the Mandible (Rami Mandibulae). 
The perpendicular portions or rami are of a quadrilateral form. Each presents 
for examination two surfaces, four borders, and two processes. 
Surfaces. External Surface.-The external surface is flat, marked with ridges, 
and gives attachment throughout nearly the whole of its extent to the Masseter 
muscle. 
Internal Surface.-The internal surface presents about its centre an oblique 
foramen (foramen mandibulare) of the inferior dental canal (canalis mandibidoe}, for 
the passage of the inferior dental vessels and nerve. The margin of this opening 
is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, 
the lingula (lingula mandibidce), which gives attachment to the internal lateral 
ligament of the lower jaw, and at its lower and back part a notch leading to 
a groove, the mylo-^voidean groove (sulcus mglohyoideus), which runs obliquely 
downward to the 1 X part of the submaxillary fossa, and lodges the mylo-hyoid 
vessels and nerve. Behind the groove is a rough surface, for the insertion of the 
Internal pterygoid muscle. The inferior dental canal runs obliquely downward 
and forward in the substance of the ramus, and then horizontally forward in the 
body; it is here placed under the alveoli, with which it communicates by small 
openings. On arriving at the incisor teeth, it turns back to communicate with 
the mental foramen, giving off two small canals, which run forward, to be lost in 
the cancellous tissue of the bone beneath the incisor teeth. This canal, in the 
posterior two-thirds of the bone, is situated nearer the internal surface of the 
jaw; and in the anterior third, nearer its external surface. Its walls are com- 
posed of compact tissue at either extremity, and of cancellous in the centre. It 
contains the inferior dental vessels and nerve, from which branches are distributed 
to the teeth through small apertures at the bases of the alveoli. 
Borders.-The lower border of the ramus is thick, straight, and continuous 
with the body of the bone. At its junction with the posterior border is the angle 
of the jaw (angulus mandibidce). The outer portion of the angle is called the 
gonion. The angle is either inverted or everted, and marked by rough, oblique 
ridges on each side, for the attachment of the Masseter externally, and the 
Internal pterygoid internally; the stylo-maxillary ligament is attached to the angle 
between these muscles. The anterior border is thin above, thicker below, and 
continuous with the external oblique line. The posterior border is thick, 
smooth, rounded, and covered by the parotid gland. The upper border of the 
ramus is thin, and presents two processes, separated by a deep concavity, the 
sigmoid notch (incisura mandibulw). Of these processes, the anterior is the 
coronoid, the posterior the condyloid. THE MAXILLARY BONE 
125 
Coronoid Process (processus coronoideus).-The coronoid process is a thin, flat- 
tened, triangular eminence of bone, which varies in shape and size in different 
subjects, and serves chiefly for the attachment of the Temporal muscle. Its external 
surface is smooth, and affords attachment to the Temporal and Masseter muscles. 
Its internal surface gives attachment to the Temporal muscle and presents the 
commencement of a longitudinal ridge, which is continued to the posterior part 
of the alveolar process. On the outer side of this ridge is a deep groove, con- 
tinued below on the outer side of the alveolar process; this ridge and part of the 
groove afford attachment, above, to the Temporal; below, to the Buccinator 
muscle. 
Condyloid Process (processus condyloideus).-The condyloid process, shorter but 
thicker than the coronoid, consists of two portions: the condyle (capitulum man- 
dibular), and the constricted portion which supports the condyle, the neck (collum 
mandibular). The condyle is of an oblong form, its long axis being transverse, and 
set obliquely on the neck in such a manner that its outer end is a little more 
forward and a little higher than its inner. It is convex from before backward 
and from side to side, the articular surface extending farther on the posterior 
than on the anterior aspect. At its outer extremity is a small tubercle for the 
attachment of the external lateral ligament of the temporo-mandibular joint. 
The neck of the condyle is flattened from before backward, and strengthened 
by ridges which descend from the fore part and sides of the condyle. Its lateral 
margins are narrow, the external one giving attachment to part of the external 
lateral ligament. Its posterior surface is convex; its anterior is hollowed out on 
its inner side by a depression, the pterygoid depression (fovea pterygoidea), for the 
attachment of the External pterygoid muscle. 
The Sigmoid Notch (incisura mandibular), separating the two processes, is a 
deep semilunar depression, crossed by the masseteric vessels and nerve. 
Development.-The lower jaw is developed principally from membrane, but 
partly from cartilage. The process of ossification comm^avrs early-earlier than 
in any other bone except the clavicle. The greater part of the bone is formed from 
a centre of ossification (dentary), which appears between the and sixth week 
in the membrane on the outer surface of Meckel's cartilageA second centre 
(splenial) appears in the membrane on the inner surface of the cartilage, and 
from this centre the inner wall of the sockets of the teeth is formed; this termi- 
nates above in the lingula. The anterior extremity of Meckel's cartilage becomes 
ossified, forming the body of the bone on each side of the symphysis. Two supple- 
mental patches of cartilage appear at the condyle and at the angle, in each of 
which a centre of ossification for these parts appears; the coronoid process is also 
ossified from a separate centre. At birth the bone consists of two halves, united 
by a fibrous symphysis, in which ossification takes place during the first year. 
Articulation.-With the glenoid fossae of the two temporal bones. 
Attachment of Muscles.-To fifteen pairs: to its external surface, commencing 
at the symphysis, and proceeding backward: Levator menti, Depressor labii infe- 
rioris, Depressor anguli oris, Platysma myoides, Buccinator, Masseter; a portion 
of the Orbicularis oris (Accessorii orbicularis inferioris) is also attached to this 
surface. To its internal surface, commencingat the same point: Genio-hyo-glossus, 
Genio-hyoideus, Mylo-hyoideus, Digastric, Superior constrictor, Temporal, Inter- 
nal pterygoid, External pterygoid. 
The changes which the lower jaw undergoes after birth relate (1) to the alterations effected 
in the body of the bone by the first and second dentitions, the loss of the teeth in the aged, and 
the subsequent absorption of the alveoli; (2) to the size and situation of the dental canal; and 
(3) to the angle at which the ramus joins with the body. 
CHANGES PRODUCED IN THE LOWER JAW BY AGE. 126 
THE SKELETON 
Side View of the Lower Jaw at Different Periods of Life. 
At birth (Fig. 91) the bone consists of lateral halves, united by fibrous tissue. The body is 
a mere shell of bone, containing the sockets of the two incisor, the canine, and the two tem- 
porary molar teeth, imperfectly partitioned from one another. The dental canal is of large size, 
and runs near the lower border of the bone, the mental foramen opening beneath the socket of 
the first molar. The angle is obtuse (175 degrees), and the condyloid portion nearly in the 
same horizontal line with the body; the neck of the condyle is short, and bent backward. The 
coronoid process is of comparatively large size, and situated at right angles with the rest of 
the bone. 
Fig. 91.-Lower jaw bone in newborn. (Spalteholz.) 
Fig. 92.-In child six to seven years of age. 
(Spalteholz.) 
After birth (Fig. 92) the two segments of the bone become joined at the symphysis, from 
below upward, in the first year; but a trace of separation may be visible in the beginning of the 
second year near the alveolar margin. The body becomes elongated in its whole length, but 
more especially behind the mental foramen, to provide space for the three additional teeth 
developed in this part. The depth of the body becomes greater, owing to increased growth of 
the alveolar part, to afford room for the fangs of the teeth, and by thickening of the subdental 
portion, which enables the jaw to withstand the powerful action of the masticatory muscles; but 
the alveolar portion is the deeper of the two, and, consequently, the chief part of the body lies 
above the oblique line. The dental canal after the second dentition is situated just above the 
level of the mylo-hyoid ridge, and the mental foramen occupies the position usual to it in the 
adult. The angle becomes less obtuse, owing to the separation of the jaws by the teeth. (About 
the fourth year it is 40 degrees.) 
Fig. 93.-In the adult. (Spalteholz.) 
In the adult (Fig. 93) the alveolar and basilar portions of the body are usually of equal 
depth. The mental foramen opens midway between the upper and lower border of the bone, THE SUTURES 
127 
and the dental canal runs nearly parallel with the mylo-hyoid line. The ramus is almost vertical 
in direction, and joins the body nearly at right angles. 
In old age (Fig. 94) the bone becomes greatly reduced in size; for with the loss of the teeth 
the alveolar process is absorbed, and the basilar part of the bone alone remains, consequently, 
Fig. 94.-In old age. (Spalteholz.) 
the chief part of the bone is below the oblique line. The dental canal, with the mental foramen 
opening from it, is close to the alveolar border. The rami are oblique in direction, the angle 
obtuse, and the neck of the condyle more or less bent backward. 
The Sutures. 
The bones of the cranium and face are connected to each other by means of 
sutures. That is, the articulating surfaces or edges of the bones are more or less 
roughened or uneven, and are closely adapted to each other, , small amount of 
intervening fibrous tissue, the sutural ligament, fastening them together. The 
cranial sutures may be divided into three sets: 1. Those at the vertex of the 
skull. 2. Those at the side of the skull. 3. Those at the base. 
The sutures at the vertex of the skull are four: the metopic, the sagittal, the 
coronal, and the lambdoid. 
The Metopic or Frontal Suture (sutura frontalis} is usually noted in adults as a 
trivial fissure, just above the glabella. At birth the two halves of the frontal 
bone are separated by the suture. This suture is, as a rule, almost completely 
or completely closed during the fifth or sixth year, but occasionally it remains 
intact (in about 8 per cent, of Europeans according to Prof. Cunningham). 
The Interparietal or Sagittal Suture (sutura sagittalis} is formed by the junction 
of the two parietal bones, and extends from the middle of the frontal bone back- 
ward to the superior angle of the occipital. This suture is sometimes perforated, 
near its posterior extremity, by the parietal foramen; and in front, where it joins 
the coronal suture, a space is occasionally left which encloses a large Wormian 
bone. 
The Fronto-parietal or Coronal Suture {sutura coronalis} extends transversely 
across the vertex of the skull, and connects the frontal with the parietal bones. 
It commences at the extremity of the greater wing of the sphenoid on one side, 
and terminates at the same point on the opposite side. The dentations of the 
suture are more marked at the sides than at the summit, and are so constructed 
that the frontal rests on the parietal above, whilst laterally the frontal supports 
the parietal. 128 
THE SKELETON 
The Occipito-parietal or Lambdoid Suture (sutura lambdoidea), so called from 
its resemblance to the Greek letter A, connects the occipital with the parietal 
bones. It commences on each side at the mastoid portion of the temporal bone, 
and inclines upward to the end of the sagittal suture. The dentations of this 
suture are very deep and distinct, and are often interrupted by several small 
Wormian bones. 
The sutures at the side of the skull extend from the external angular process of 
the frontal bone to the lower end of the lambdoid suture behind. 'The anterior portion 
is formed between the lateral part of the frontal bone above and the malar and great 
wing of the sphenoid below, forming the fronto-malar suture (sutura zygomatico- 
jrontalis) and fronto-sphenoidal suture (sutura s pheno jront alls). These sutures 
can also be seen in the orbit, and form part of the so-called transverse facial 
suture. The posterior portion is formed between the parietal bone above and 
the great wing of the sphenoid, the squamous and mastoid portions of the temporal 
bone below, forming the spheno-parietal, squamo-parietal, and masto-parietal sutures. 
The spheno-parietal (sutura sphenoparietalis) is very short; it is formed by the 
tip of the great wing of the sphenoid, which overlaps the anterior inferior angle 
of the parietal bone. 
The squamo-parietal or squamous suture (sutura squamosa) is arched. It is 
formed by the squamous portion of the temporal bone overlapping the middle 
division of the lower border of the parietal. 
The masto-parietal (sutura parietomastoidea) is a short suture, deeply dentated, 
formed by the posterior inferior angle of the parietal and the superior border of 
the mastoid portion of the temporal. 
The sutures at the base of the skull are the basilar in the centre, and on each 
side the petro-occipital, the masto-occipital, the petro-sphenoidal, and the squamo- 
sphenoidal. 
The Basilar Suture (fissura sphenooccipitalis) is formed by the junction of the 
basilar surface of the occipital bone with the posterior surface of the body of 
the sphenoid. At an early period of life a thin plate of cartilage exists between 
these bones, but in the adult they become fused into one (synchondrosis spheno- 
occipitalis). Between the outer extremity of the basilar suture and the termina- 
tion of the lambdoid an irregular suture exists, which is subdivided into two por- 
tions. The inner portion, formed by the union of the petrous part of the temporal 
with the occipital bone, is termed the petro-occipital fissure (fissura petrooccip ital is). 
The outer portion, formed by the junction of the mastoid part of the temporal 
with the occipital, is called the masto-occipital suture (sutura occipitomastoidea). 
Between the bones forming the petro-occipital suture a thin plate of cartilage 
exists; in the masto-occipital is occasionally found the opening of the mastoid 
foramen. Between the outer extremity of the basilar suture and the spheno- 
parietal an irregular suture may be seen, formed by the union of the sphenoid 
with the temporal bone. The inner and smaller portion of this suture is termed 
the petro-sphenoidal fissure (fissura sphenopetrosa); it is formed between the 
petrous portion of the temporal and the great wing of the sphenoid; the outer 
portion, of greater length and arched, is formed between the squamous portion 
of the temporal and the great wing of the sphenoid; it is called the squamo- 
sphenoidal suture (sutura sphenosquamosa). 
The cranial bones are connected with those of the face, and the facial bones 
with each other, by numerous sutures, which, though distinctly marked, have 
received no special names. The only remaining suture deserving especial con- 
sideration is the transverse suture. This extends across the upper part of the face, 
and is formed by the junction of the frontal with the facial bones: it extends from 
the external angular process of one side to the same point on the opposite side, 
and connects the frontal with the malar, the sphenoid, the ethmoid, the lachrymal, THE VERTEX OF THE SKULL 
129 
the superior maxillary, and the nasal bones on each side (sutura zygomatico- 
jrontalis-, the orbital portion of the sutura sphenofrontalis, sutura fronto- 
ethmoldalis, sutura frontolacrimalis, sutura frontomaxillaris, sutura nasofrontalis). 
The sutures remain separate for a considerable period after the complete for- 
mation of the skull. It is probable that they serve the purpose of permitting the 
growth of the bones at their margins, while their peculiar formation, together 
with the interposition of the sutural ligament between the bones forming them, 
prevents the dispersion of blows or jars received upon the skull. Humphry 
remarks, "that, as a general rule, the sutures are first obliterated at the parts in 
which the ossification of the skull was last completed-viz., in the neighborhood 
of the fontanelles; and the cranial bones seem in this respect to observe a similar 
law to that which regulates the union of the epiphyses to the shafts of the long 
bones." The same author remarks that the time of their disappearance is ex- 
tremely variable: they are sometimes found well marked in skulls edentulous 
with age, while in others which have only just reached maturity they can hardly 
be traced. The obliteration of the sutures takes place sooner on the inner than 
on the outer surface of the skull. The sagittal and coronal sutures are as a rule 
the first to become ossified-the process starting near the posterior extremity of 
the former and the lower ends of the latter. 
THE SKULL AS A WHOLE. 
The skull, formed by the union of the several cranial and facial bones already 
described, when considered as a whole is divisible into five regions: a superior 
region or vertex, an inferior region or base, two lateral regions, and an anterior 
region, the face. 
The Vertex of the Skull. 
The superior region, or vertex, presents two surfaces, an external and an 
internal. 
Surfaces. External Surface. (This surface as seen from above is called the 
norma verticalis.)-The external surface is bounded, in front, by the glabella 
and supraorbital ridges; behind, by the occipital protuberance and superior 
curved lines of the occipital bone; laterally, by an imaginary line extending from 
the outer end of the superior curved line, along the temporal ridge, to the exter- 
nal angular process of the frontal bone. This surface includes the greater part of 
the vertical portion of the frontal, the greater part of the parietal, and the superior 
third of the occipital bone; it is smooth, convex, of an elongated oval form, crossed 
transversely by the coronal suture, and from before backward by the sagittal, 
which terminates behind in the lambdoid. The point of junction of the coronal 
and sagittal sutures is named the bregma, and is represented by a line drawn verti- 
cally upward from the external auditory meatus, the head being in its normal posi- 
tion. The point of junction of the sagittal and lambdoid sutures is called the 
lambda, and is about 2f inches above the external occipital protuberance. From 
before backward may be seen the frontal eminences and remains of the suture 
connecting the two lateral halves of the frontal bone; on each side of the sagittal 
suture are the parietal foramen and parietal eminence, and still more posteriorly 
the convex surface of the occipital bone. In the neighborhood of the parietal 
foramen the skull is often flattened, and the name of obelion is sometimes given 
to that point of the sagittal suture which lies exactly opposite to the parietal 
foramen. 
Internal or Cerebral Surface.-The internal surface is concave, presents depres- 
sions for the convolutions of the cerebrum, and numerous furrows for the lodge- 
ment of branches of the meningeal arteries. Along the middle line of this 130 
THE SKELETON 
surface is a longitudinal groove, narrow in front, where it commences at the 
frontal crest, but broader behind, where it lodges the superior longitudinal 
sinus, and by its margin affords attachment to the falx cerebri. On either side 
of it are several depressions for the Pacchionian bodies, and at its back part 
the internal openings of the parietal foramina. This surface is crossed, in front, 
by the coronal suture; from before backward by the sagittal; behind, by the 
lambdoid. 
The Base of the Skull (the Skull being without the Mandible). 
The inferior region, or base of the skull, presents two surfaces-an internal 
or cerebral, and an external or basilar. 
Surfaces. Internal Upper or Cerebral Surface.-The internal or cerebral surface 
(Fig. 95) presents three fossae, called the anterior, middle, and posterior fossae of the 
cranium. 
Anterior Fossa (fossa cranii anterior).-The anterior fossa is formed by the 
orbital plates of the frontal, the cribriform plate of the ethmoid, the anterior 
third of the superior surface of the body, and the upper surface of the lesser wings 
of the sphenoid bone. It is the most elevated of the three fossae, convex exter- 
nally where it corresponds to the roof of the orbit, concave in the median line in 
the situation of the cribriform plate of the ethmoid. It is traversed by three sutures, 
the ethmo-frontal, ethmo-sphenoidal, and fronto-sphenoidal, and lodges the frontal 
lobe of the cerebrum. It presents, in the median line, from before backward, the 
commencement of the groove for the superior longitudinal sinus and the frontal 
crest for the attachment of the falx cerebri; the foramen caecum, an aperture formed 
between the frontal bone and the crista galli of the ethmoid, which, if pervious, 
transmits a small vein from the nose to the superior longitudinal sinus; behind the 
foramen caecum, the crista galli, the posterior margin of which affords attachment 
to the falx cerebri; on either side of the crista galli, the cribriform plate, which sup- 
ports the olfactory bulb, and presents three rows of foramina for the transmission 
of its nervous filaments, and in front a slit-like opening for the nasal branch of 
the ophthalmic division of the fifth nerve. On the outer side of each olfactory 
groove are the internal openings of the anterior and posterior ethmoidal foramina; 
the former, situated about the middle of the outer margin of the olfactory 
groove, transmits the anterior ethmoidal vessels and the nasal nerve, which latter 
runs in a depression along the surface of the ethmoid to the slit-like opening above 
mentioned; while the posterior ethmoidal foramen opens at the back part of this 
margin under cover of the projecting lamina of the sphenoid, and transmits the 
posterior ethmoidal vessels. Farther back in the middle line is the ethmoidal spine, 
bounded behind by a slight elevation, separating two shallow longitudinal grooves 
which support the olfactory lobes. Behind this is a transverse sharp ridge, run- 
ning outward on either side to the anterior margin of the optic foramen, and sepa- 
rating the anterior from the middle fossa of the base of the skull. The anterior 
fossa presents, laterally, depressions for the convolutions of the brain and grooves 
for the lodgement of the anterior meningeal arteries. 
Middle Fossa (fossa cranii media).-The middle fossa, deeper than the pre- 
ceding, is narrow in the middle line, but becomes wider at the side of the skull. It 
is bounded in front by the posterior margin of the lesser wing of the sphenoid, the 
anterior clinoid process, and the ridge forming the anterior margin of the optic 
groove; behind, by the superior border of the petrous portion of the temporal and 
the dorsum ephippii; externally by the squamous portion of the temporal anterior 
inferior angle of the parietal bone, and greater wing of the sphenoid. It is trav- 
ersed by four sutures, the squamo-parietal, spheno-parietal, squamo-sphenoidal, 
and petro-sphenoidal. In the middle line, from before backward, is the optic THE BASE OF THE SKULL 
groove, behind which lies the optic commissure; the groove terminates on each side 
in the optic foramen, for the passage of the optic nerve and ophthalmic artery; 
131 
Groove for superior longitudinal sinus. 
Grooves for anterior meningeal artery.. 
Foramen ceecum.. 
Slit for nasal nerve.. 
Crista galli.. 
Groove for nasal nerve. - 
Anterior ethmoidal foramen.- 
Orifices for olfactory nerves. 
Posterior ethmoidal foramen. 
Ethmoidal spine. 
Olfactory grooves. 
Optic foramen,. 
Optic groove.. 
Anterior clinoid process.. 
Olivary process.. 
Middle clinoid process., 
Posterior clinoid process. 
Groove for 6th nerve. 
Foramen lacerum medium. 
Depression for Gasserian ganglion. 
Orifice of carotid canal. 
Meatus auditorius internus.. 
Foramen lacerum poster ius. 
Slit for dura mater.- 
Superior petrosal groove- 
Anterior condyloid foramen. 
Posterior condyloid foramen. 
Aqu&ductus vestibuli. 
Fo ramen 
magnum. 
Mastoid foramen.- 
Posterior meningeal grooves.- 
Fig. 95.-Base of the skull. Inner or cerebral surface. 
behind the optic groove is the olivary process and laterally the anterior clinoid pro- 
cesses, to which are attached processes of the tentorium cerebelli. Farther back is 
the sella turcica, a deep depression which lodges the pituitary gland, bounded in 132 
THE SKELETON 
front by a small eminence on either side, the middle clinoid process, and behind by 
a broad, square plate of bone, the dorsum ephippii, surmounted at each superior 
angle by a tubercle, the posterior clinoid process; beneath the latter process is 
a notch, for the sixth nerve. On each side of the sella turcica is the cavernous 
groove: it is broad, shallow, and curved somewhat like the italic letter f; it com- 
mences behind at the foramen lacerum medium, and terminates on the inner 
side of the anterior clinoid process, and presents along its outer margin a ridge 
of bone. This groove lodges the cavernous sinus, the internal carotid artery, 
and the nerves of the orbit. The sides of the middle fossa are of considerable 
depth; they present depressions for the convolutions of the brain and grooves 
for the branches of the middle meningeal artery; the latter commence on the 
outer side of the foramen spinosum, and consist of two large branches, an anterior 
and a posterior; the former passing upward and forward to the anterior inferior 
angle of the parietal bone, the latter passing upward and backward. The fol- 
lowing foramina may also be seen from before backward: Most anteriorly is the 
foramen lacerum anterius, or sphenoidal fissure (fissura orbitalis superior), formed 
above by the lesser wing of the sphenoid; below, by the greater wing; internally, by 
the body of the sphenoid; and sometimes completed externally by the orbital plate 
of the frontal bone. It transmits the third, the fourth, the three branches of the 
ophthalmic division of the fifth, the sixth nerve, some filaments from the cavernous 
plexus of the sympathetic, the orbital branch of the middle meningeal artery, a 
recurrent branch from the lachrymal artery to the dura mater, and the ophthalmic 
vein. Behind the inner extremity of the sphenoidal fissure is the foramen rotundum, 
for the passage of the second division of the fifth or the superior maxillary nerve; 
still more posteriorly is seen a small orifice, the foramen Vesalii,an opening situated 
between the foramen rotundum and ovale, a little internal to both: it varies in size 
in different individuals, and is often absent; when present it transmits a small vein. 
It opens below into the pterygoid fossa, just at the outer side of the scaphoid 
depression. Behind and external to the latter opening is the foramen ovale, which 
transmits the third division of the fifth or the inferior maxillary nerve, the small 
meningeal artery, and the small petrosal nerve.1 On the outer side of the foramen 
ovale is the foramen spinosum, for the passage of the middle meningeal artery; and 
on the inner side of the foramen ovale is the foramen lacerum medium. The lower 
part of this aperture is filled with cartilage in the recent state. The Vidian nerve 
and a meningeal branch from the ascending pharyngeal artery pierce this car- 
tilage. On the anterior surface of the petrous portion of the temporal bone is 
seen, from without inward, the eminence caused by the projection of the superior 
semicircular canal; in front of and a little outside this is a depression corresponding 
to the roof of the tympanum; the groove leading to the hiatus Fallopii, for the 
transmission of the petrosal branch of the Vidian nerve and the petrosal branch 
of the middle meningeal artery; beneath it, the smaller groove, for the passage 
of the lesser petrosal nerve; and, near the apex of the bone, the depression for 
the Gasserian ganglion; and the internal orifice of the carotid canal (foramen 
caroticum internum), for the passage of the internal carotid artery and carotid 
plexus of nerves. 
Posterior Fossa (fossa cranii posterior).-The posterior fossa, deeply concave, 
is the largest of the three, and situated on a lower level than either of the preceding. 
It is formed by the posterior third of the superior surface of the body of the sphe- 
noid, by the occipital, the petrous and mastoid portions of the temporal, and the 
posterior inferior angle of the parietal bone; it is crossed bv four sutures, the petro- 
occipital, the masto-occipital, the masto-parietal, and the basilar; and lodges the 
cerebellum, pons Varolii, and medulla oblongata. It is separated from the middle 
1 See footnote, p. 95. THE BASE OE THE SKULL 
133 
fossa in the median line by the dorsum ephippii, and on each side by the superior 
border of the petrous portion of the temporal bone. This border serves for the 
attachment of the tentorium cerebelli, is grooved for the superior petrosal sinus, 
and at its inner extremity presents a notch, upon which rests the fifth nerve. The 
circumference of the fossa is bounded posteriorly by the grooves for the lateral 
sinuses. In the centre of this fossa is the foramen magnum, bounded on either 
side by a rough tubercle, which gives attachment to the odontoid or check liga- 
ments; and a little above these are seen the internal openings of the anterior 
condyloid foramina, through which pass the hypoglossal nerves and meningeal 
branches from the ascending pharyngeal arteries. In front of the foramen mag- 
num is a grooved surface, formed by the basilar process of the occipital bone and 
by the posterior third of the superior surface of the body of the sphenoid, which 
supports the medulla oblongata and pons Varolii, and articulates on each side 
with the petrous portion of the temporal bone, forming the petro-occipital suture, 
the anterior half of which is grooved for the inferior petrosal sinus, the posterior 
half being encroached upon by the foramen lacerum posterius or jugular foramen 
(foramen jugular e). This foramen presents three compartments: through the ante- 
rior passes the inferior petrosal sinus; through the posterior, the lateral sinus and 
some meningeal branches from the occipital and ascending pharyngeal arteries; 
and through the middle, the glosso-pharyngeal, pneumogastric, and spinal acces- 
sory nerves. Above the jugular foramen is the internal auditory meatus, for the 
facial and auditory nerves and auditory artery; behind and external to this is the 
slit-like opening leading into the aquseductus vestibuli, which lodges the ductus 
endolymphaticus; while between the two latter, and near the superior border of 
the petrous portion, is a small, triangular depression, the remains of the floccular 
fossa, which lodges a process of the dura mater and occasionally transmits a small 
vein into the substance of the bone. Behind the foramen magnum are the inferior 
occipital fossae, which lodge the hemispheres of the cerebellum, separated from 
one another by the internal occipital crest, which serves for the attachment of the 
falx cerebelli and lodges the occipital sinus. The posterior fossae are surmounted 
above by the deep transverse grooves for the lodgement of the lateral sinuses. 
These channels, in their passage outward, groove the occipital bone, the posterior 
inferior angle of the parietal, the mastoid portion of the temporal, and the jugular 
process of the occipital, and terminate at the back part of the jugular foramen. 
Where this sinus grooves the mastoid portion of the temporal bone the orifice of 
the mastoid foramen may be seen. Just previous to the termination of the groove 
the posterior condyloid foramen opens into it. Neither foramen is constant. 
External Under or Basilar Surface (the view from below is called the norma 
basalis).-The external surface of the base of the skull (Fig. 96) is extremely 
irregular. It is bounded in front by the incisor teeth in the upper jaw; behind 
by the superior curved lines of the occipital bone; and laterally by the alve- 
olar arch, the lower border of the malar bone, the zygoma, and an imaginary line 
extending from the zygoma to the mastoid process and extremity of the superior 
curved line of the occiput. It is formed by the palate processes of the superior 
maxillary and palate bones, the vomer, the pterygoid processes, under surface 
of the great wing, spinous processes and part of the body of the sphenoid, the 
under surface of the squamous, mastoid, and petrous portions of the temporal, 
and the under surface of the occipital bone. The anterior part of the base of the 
skull is raised above the level of the rest of this surface (when the skull is turned 
over for the purpose of examination), surrounded by the alveolar process, which is 
thicker behind than in front, and excavated by sixteen depressions for lodging the 
teeth of the upper jaw, the cavities varying in depth and size according to the teeth 
they contain. Immediately behind the incisor teeth is the anterior palatine fossa 
(foramen incisivum). At the bottom of this fossa may usually be seen four apertures: THE SKELETON 
134 
two placed laterally, the foramina of Stenson, which open above, one in the floor of 
each nostril, and transmit the anterior branch of the posterior palatine vessels, and 
'Anterior palatine fossa. 
Transmits left naso-palatine nerve. 
Transmits anterior palatine vessel. 
Transmits right naso-palatine nerve. 
Accessory palatine foramina. 
Posterior nasal spine. 
AZYQOS UVULAE. 
'Hamular process. 
-Sphenoid process of palate. 
■Ptery go-palatine canal. 
-TENSOR TYMPANI, 
■Pharyngeal spine for 
SUPERIOR constrictor. 
.Situation of Eustachian tube and 
canal for tensor tympani. 
TENSOR PALATI. 
Canal for Jacobson's nerve. 
Aquxductus cochlex. 
Foramen lacerum poster ius. 
■Canalfor Arnold's nerve. 
■Auricular fissure. 
Foramen 
magnum. 
Fig. 96.-Base of the skull. External surface. THE BASE OE THE SKULL 
135 
two in the median line in the intermaxillary suture, the foramina of Scarpa, one 
in front of the other, the anterior transmitting the left, and the posterior (the 
larger) the right, naso-palatine nerve. These two lateral canals are sometimes 
wanting, or they may join to form a single one, or one of them may open into one 
of the lateral canals above referred to. The palatine vault is concave, uneven, 
perforated by numerous foramina, marked by depressions for the palatine glands, 
and crossed by a crucial suture, formed by the junction of the four bones of which 
it is composed. At the front part of this surface a delicate linear suture may 
frequently be seen, passing outward and forward from the anterior palatine fossa 
to the interval between the lateral incisor and canine teeth, and marking off the 
pre-maxillary portion of the bone. At each posterior angle of the hard palate is 
the posterior palatine foramen, for the transmission of the posterior palatine vessels 
and great descending palatine nerve; and running forward and inward from it a 
groove, for the same vessels and nerve. Behind the posterior palatine foramen 
is the tuberosity of the palate bone, perforated by one or more accessory posterior 
palatine canals, and marked by the commencement of a ridge which runs trans- 
versely inward, and serves for the attachment of the tendinous expansion of the 
Tensor palati muscle. Projecting backward from the centre of the posterior 
border of the hard palate is the posterior nasal spine, for the attachment of the 
Azygos uvulte muscle. Behind and above the hard palate is the posterior aper- 
ture of the nares, divided into two parts by the vomer, bounded above by the 
body of the sphenoid, below by the horizontal plate of the palate bone, and lat- 
erally by the internal pterygoid plate of the sphenoid. Each aperture measures 
about an inch in the vertical and about half an inch in the transverse direction. 
At the base of the vomer may be seen the expanded ala* of this bone, receiving 
between them, on each side, the rostrum of the sphenoid. Near the lateral margins 
of the vomer, at the root of the pterygoid processes, are the pterygo-palatine canals. 
The pterygoid process, which bounds the posterior nares on each side, presents 
near its base the pterygoid or Vidian canal (canalis pterygoideus) the Vidian nerve 
and artery. Each process consists of two plates, which bifurcate at the extremity to 
receive the tuberosity of the palate bone, and are separated behind by the ptery- 
goid fossa, which lodges the Internal pterygoid muscle. The internal plate is 
long and narrow, presenting on the outer side of its base the scaphoid fossa, for 
the origin of the Tensor palati muscle, and at its extremity the hamular process, 
around which the tendon of this muscle turns. The external pterygoid plate is 
broad, forms the inner boundary of the zygomatic fossa, and affords attachment 
by its outer surface to the External pterygoid muscle. 
Behind the nasal fossa? in the middle line is the basilar surface of the occipital 
bone, presenting in its centre the pharyngeal spine, for the attachment of the 
Superior constrictor muscle of the pharynx, with depressions on each side for 
the insertion of the Rectus capitis anticus major and minor. At the base of the 
external pterygoid plate is the foramen ovale, for the transmission of the third 
division of the fifth nerve, the small meningeal artery, and sometimes the small 
petrosal nerve; behind this, the foramen spinosum, which transmits the middle 
meningeal artery, and the prominent spinous process of the sphenoid, which gives 
attachment to the internal lateral ligament of the lower jaw and the Tensor palati 
muscle. External to the spinous process is the glenoid fossa, divided into two parts 
by the Glaserian fissure (page 84), the anterior portion concave, smooth, bounded 
in front by the eminentia articularis, and serving for the articulation of the condyle 
of the lower jaw; the posterior portion rough, bounded behind by the tympanic 
plate, and serving for the reception of part of the parotid gland. Emerging from 
between the laminae of the vaginal process of the tympanic plate is the styloid 
process, and at the base of this process is the stylo-mastoid foramen, for the exit of 
the facial nerve and entrance of the stylo-mastoid artery. External to the stylo- 136 
THE SKELETON 
mastoid foramen is the auricular fissure, for the auricular branch of the pneumo- 
gastric, bounded behind by the mastoid process. Upon the inner side of the mas- 
toid process is a deep groove, the digastric fossa; and a little more internally the 
occipital groove, for the occipital artery. At the base of the internal pterygoid plate 
is a large and somewhat triangular aperture, the foramen lacerum medium, bounded 
in front by the great wing of the sphenoid, behind by the apex of the petrous por- 
tion of the temporal bone, and internally by the body of the sphenoid and basilar 
process of the occipital bone: it presents in front the posterior orifice of the Vidian 
canal; behind, the aperture of the carotid canal. The basilar surface of this open- 
ing is filled in the recent state by fibro-cartilaginous substance; across its upper 
or cerebral aspect passes the internal carotid artery. External to this aperture the 
petro-sphenoidal suture is observed, at the outer termination of which is seen the 
orifice of the canal for the Eustachian tube and that for the Tensor tympani 
muscle. Behind this suture is seen the under surface of the petrous portion of the 
temporal bone, presenting, from within outward, the quadrilateral, rough surface, 
part of which affords attachment to the Levator palati and Tensor tympani mus- 
cles; external to this surface the orifices of the carotid canal (foramen caroticum 
externum) and the aquseductus cochleae, the former transmitting the internal 
carotid artery and the ascending branches of the superior cervical ganglion 
of the sympathetic, the latter serving for the passage of a small artery and vein 
to the cochlea. Behind the carotid canal is a large aperture, the jugular foramen, 
formed in front by the petrous portion of the temporal, and behind by the 
occipital; it is generally larger on the right than on the left side, and is divided 
into three compartments by processes of dura mater. The anterior is for the 
passage of the inferior petrosal sinus; the posterior, for the lateral sinus and 
some meningeal branches from the occipital and ascending pharyngeal arteries; 
the central one, for the glosso-pharyngeal, pneumogastric, and spinal accessory 
nerves. On the ridge of bone dividing the carotid canal from the jugular fora- 
men is the small foramen for the transmission of Jacobson's nerve; and on the 
wall of the jugular foramen, near the root of the styloid process, is the small 
aperture for the transmission of Arnold's nerve. Behind the basilar surface of 
the occipital bone is the foramen magnum, bounded on each side by the con- 
dyles, rough internally for the attachment of the check or odontoid ligaments, and 
presenting externally a rough surface, the jugular process, which serves for the 
attachment of the Rectus capitis lateralis muscle and the lateral occipito-atlantal 
ligament. On either side of each condyle anteriorly is the anterior condyloid fossa, 
perforated by the anterior condyloid foramen, for the passage of the hypoglossal 
nerve and often a meningeal branch of the ascending pharyngeal artery. Behind 
each condyle is the posterior condyloid fossa, perforated by the posterior condyloid 
foramen, for the transmission of a vein to the lateral sinus. Behind the foramen 
magnum is the external occipital crest, terminating above at the external occipital 
protuberance, whilst on each side are seen the superior and inferior curved lines; 
these, as well as the surfaces of bone between them, are rough for the attachment 
of the muscles, which are enumerated on page 76. 
The Lateral Region of the Skull. 
The view of the lateral region of the skull from the side is known as the norma 
lateralis. The lateral region is of a somewhat triangular form, the base of the tri- 
angle being formed by a line extending from the external angular process of the 
frontal bone along the temporal ridge backward to the outer extremity of the supe- 
rior curved line of the occiput; and the sides by two lines, the one drawn down- 
ward and backward from the external angular process of the frontal bone to the 
angle of the lower jaw, the other from the angle of the jaw upward and back- THE LATERAL REGION OF THE SKULL 
ward to the outer extremity of the superior curved line. This region is divisible into 
three portions-temporal fossa, mastoid portion, and zygomatic or infratemporal fossa. 
The Temporal Fossa Qossa temporalis}.-The temporal fossa is bounded above 
and behind by the temporal ridges, which extend from the external angular process 
of the frontal upward and backward across the frontal and parietal bones, curving 
downward behind to terminate in the posterior root of the zygomatic process, supra- 
137 
Fig. 97.-Side view of the skull. (Cryer.) 
mastoid crest. Tn front it is bounded by the frontal, malar, and great wing of the 
sphenoid; externally by the zygomatic arch formed conjointly by the malar and 
temporal bones; below, it is separated from the zygomatic fossa by the pterygoid 
ridge, seen on the outer surface of the great wing of the sphenoid. This fossa is 
formed by five bones, part of the frontal, great wing of the sphenoid, parietal, squa- 
mous portion of the temporal and malar bones, and is traversed by six sutures, part of 
the transverse facial, spheno-malar, coronal, spheno-parietal, squamo-parietal, and 
squamo-sphenoidal. The point where the coronal suture crosses the superior tem- 
poral ridge is sometimes named the stephanion; and the region where the four bones, 
the parietal, the frontal, the squamous, and the greater wing of the sphenoid, meet, 
at the anterior inferior angle of the parietal bone, is named the pterion. This point 
is about on a level with the external angular process of the frontal bone and about 
one and a half inches behind it. This fossa is deeply concave in front, convex 
behind, traversed by grooves which lodge branches of the deep temporal arteries, 
and filled by the Temporal muscles. 138 
THE SKELETON 
The Mastoid Portion.-The mastoid portion of the side of the skull is bounded 
in front by the tubercle of the zygoma; above, by a line which runs from the pos- 
terior root of the zygoma to the end of the mastoid-parietal suture; behind and 
below by the masto-occipital suture. It is formed by the mastoid and part of the 
scpiamous and petrous portions of the temporal bone; its surface is convex and 
rough for the attachment of muscles, and presents, from behind forward, the 
mastoid foramen, the mastoid process, the external auditory meatus surrounded by 
the tympanic plate, and, most anteriorly, the temporo-maxillary articulation. The 
point where the posterior inferior angle of the parietal meets the occipital bone 
and mastoid portion of the temporal is named the asterion. 
The Zygomatic or Infratemporal Fossa (fossa infratemporalis).-The zygo- 
matic fossa is an irregularly shaped cavity, situated below and on the inner side 
of the zygoma; bounded in front by the zygomatic surface of the superior maxil- 
lary bone and the ridge which descends from its malar process; behind, by the 
posterior border of the external pterygoid plate and the eminentia articularis; 
above, by the pterygoid ridge on the outer surface of the great wing of the 
sphenoid and the under part of the squamous portion of the temporal; below, 
by the alveolar border of the superior maxilla; internally, by the external pterygoid 
plate; and externally, by the zygomatic arch and ramus of the lower jaw (Fig. 98). 
Spheno- 
maxillary 
fissure. 
Ext. auditory 
meatus. 
Styloid 
process. 
Ext. 
pterygoid 
plate. 
Fig. 98.-Zygomatic fossa. 
It contains the lower part of the Temporal, the External and Internal pterygoid 
muscles, the internal maxillary artery and vein, and inferior maxillary nerve and 
their branches. At its upper and inner part may be observed two fissures, the 
spheno-maxillary and pterygo-maxillary fissures. 
The Spheno-maxillary Fissure (fissura orbitalis inferior), horizontal in direction, 
opens into the outer and back part of the orbit. It is formed above by the lower 
border of the orbital surface of the great wing of the sphenoid; below, by the exter- 
nal border of the orbital surface of the superior maxilla and a small part of the 
palate bone; externally, by a small part of the malar bone:1 internally, it joins at 
1 Occasionally the superior maxillary bone and the sphenoid articulate with each other at the anterior 
extremity of this fissure ; the malar is then excluded from entering into its formation. THE ANTERIOR REGION OF THE SKULL 
139 
right angles with the pterygo-maxillary fissure. This fissure opens a communication 
from the orbit into three fossae-the temporal, zygomatic, and spheno-maxillary fossa; 
it transmits the superior maxillary nerve and its orbital branch, the infraorbital 
vessels, and ascending branches from the spheno-palatine or Meckel's ganglion. 
The Pterygo-maxillary Fissure is vertical, and descends at right angles from the 
inner extremity of the preceding; it is a V-shaped interval, formed by the diver- 
gence of the superior maxillary bone from the pterygoid process of the sphenoid. 
It serves to connect the spheno-maxillary fossa with the zygomatic fossa, and 
transmits the internal maxillary artery. 
The Spheno-maxillary or Pterygo-palatine Fossa (fossa pterygopalatina) 
The spheno-maxillary fossa is a small, triangular space situated at the angle 
of junction of the spheno-maxillary and pterygo-maxillary fissures, and placed 
beneath the apex of the orbit. It is formed above by the under surface of the 
body of the sphenoid and by the orbital process of the palate bone; in front, 
by the superior maxillary bone; behind, by the anterior surface of the base of 
the pterygoid process and lower part of the anterior surface of the great wing of 
the sphenoid; internally, by the vertical plate of the palate. This fossa has 
three fissures terminating in it-the sphenoidal, spheno-maxillary, and pterygo- 
maxillary; it communicates with the orbit by the spheno-maxillary fissure; with the 
nasal fossae by the spheno-palatine foramen, and with the zygomatic fossa by the 
pterygo-maxillary fissure. It also communicates with the cavity of the cranium, 
and has opening into it five foramina. Of these, there are three on the posterior 
wall: the foramen rotundum above; below and internal to this, the Vidian canal; and 
still more inferiorly and internally, the pterygo-palatine canal. On the inner wall 
is the spheno-palatine foramen, by which the spheno-maxillary communicates with 
the nasal fossa; and below is the superior orifice of the posterior palatine canal, 
besides occasionally the orifices of the accessory posterior palatine canals. The 
fossa contains the superior maxillary nerve and Meckel's ganglion, and the termi- 
nation of the internal maxillary artery. 
The Anterior Region of the Skull. 
The view of the anterior region of the skull from the front is known as the 
norma frontalis. It forms the face, is of an oval form, presents an irregular 
surface, and is excavated for the reception of two of the organs of sense, the 
eye and the nose. It is bounded above by the glabella and margins of the 
orbit; below, by the prominence of the chin; on each side by the malar bone 
and anterior margin of the ramus of the jaw. In the median line are seen from 
above downward the glabella, and diverging from it are the superciliary ridges, 
which indicate the situation of the frontal sinuses and supports the eyebrow. 
Beneath the glabella is the fronto-nasal suture, the mid-point of which is termed 
the nasion, and below this is the arch of the nose, formed by the nasal bones, and 
the nasal processes of the superior maxillary. The nasal arch is convex from side 
to side, concave from above downward, presenting in the median line the inter- 
nasal suture (sutura internasalis), formed between the nasal bones, laterally the 
naso-maxillary suture (sutura nasomaxillaris), formed between the nasal bone and 
the nasal process of the superior maxillary bone. Below the nose is seen the 
opening of the anterior nares, which is heart-shaped, with the narrow end 
upward, and presents laterally the thin, sharp margins serving for the attach- 
ment of the lateral cartilages of the nose, and in the middle line below a 
prominent process, the anterior nasal spine, bounded by two deep notches. 
Below this is the intermaxillary suture {sutura inter maxiliar is), and on each side 
of it the incisive fossa. Beneath this fossa are the alveolar processes of the 
upper and lower jaws, containing the incisor teeth, and at the lower part of the 140 
THE SKELETON 
median line the symphysis of the chin, the mental process, with its two mental 
tubercles, separated by a median groove, and the incisive fossa of the lower jaw. 
On each side, proceeding from above downward, is the supraorbital ridge, 
terminating externally in the external angular process at its junction with the 
malar, and internally in the internal angular process; toward the inner third of 
this ridge is the supraorbital notch or foramen, for the passage of the supraorbital 
vessels and nerve. Beneath the supraorbital ridge is the opening of the orbit, 
bounded externally by the orbital ridge of the malar bone; below, by the orbital 
ridge formed by the malar and superior maxillary bones; internally, by the nasal 
process of the superior maxillary and the internal angular process of the frontal 
bone. On the outer side of the orbit is the quadrilateral anterior surface of the 
malar bone, perforated by one or two small malar foramina. Below the inferior 
margin of the orbit is the infraorbital foramen, the termination of the infraorbital 
canal, and beneath this the canine fossa, which gives attachment to the Levator 
anguli oris; still lower are the alveolar processes, containing the teeth of the upper 
and lower jaws. Beneath the alveolar arch of the lower jaw is the mental foramen, 
for the passage of the mental vessels and nerve, the external oblique line, and at 
the lower border of the bone, at the point of junction of the body with the ramus, 
a shallow groove for the passage of the facial artery. 
Orbits, Orbital Cavities, or Orbital Fossae.-The orbits (from orbis, a circle) 
(Fig. 99) are two quadrilateral pyramidal cavities, situated at the upper and anterior 
Greater wing 
..sphenoid bone. 
; Ethmoid^ 
Temporal 
bone 
TENDO OOULI 
Anterior nares 
Anterior . 
nasal spine\ 
Incisive fossa 
Groove for 
facial artery 
Fig. 99.-Antero-lateral region of the skull. (Cryer.) THE ANTERIOR REGION OF THE SKULL 
141 
part of the face, their bases being directed forward and outward, and their apices 
backward and inward, so that the axes of the two, if continued backward, would 
meet over the body of the sphenoid bone. The wide orbital opening or mouth is 
called the aditus orbitoe. The orbit is lined with periosteum, the periorbita. Each 
orbit (orbita) is formed of seven bones, the frontal, sphenoid, ethmoid, superior 
maxillary, malar, lachrymal, and palate; but three of these, the frontal, ethmoid, 
and sphenoid, enter into the formation of both orbits, so that the two cavities are 
formed of eleven bones only. Each cavity presents for examination a roof, a floor, 
an inner and an outer wall, four angles, a circumference or base, and an apex. 
The Roof (paries superior).-The roof is concave, directed downward and 
slightly forward, and formed in front by the orbital plate of the frontal; behind, 
by the lesser wing of the sphenoid. This surface presents internally the depres- 
sion for the cartilaginous pulley of the Superior oblique muscle; externally, the 
depression for the lachrymal gland; and posteriorly, the suture connecting the 
frontal and lesser wing of the sphenoid. 
The Floor (paries inferior).-The floor is directed upward and outward, and 
is of less extent than the roof; it is formed chiefly by the orbital process of 
the superior maxillary; in front, to a small extent, by the orbital process of the 
malar, and behind, by the superior surface of the orbital process of the palate. 
This surface presents at its anterior and internal part, just external to the lachrymal 
groove, a depression for the attachment of the Inferior oblique muscle; externally, 
the suture between the malar and superior maxillary bones; near its middle, the infra- 
orbital groove; and posteriorly, the suture between the maxillary and palate bones. 
Inner or Medial Wall (paries medialis).-The inner wall is flattened, nearly 
vertical, and formed from before backward by the nasal process of the superior 
maxillary, the lachrymal, os planum of the ethmoid, and a small part of the body of 
the sphenoid. This surface presents the lachrymal groove and crests of the lachrymal 
bone, and the sutures connecting the lachrymal with the superior maxillary, the 
ethmoid with the lachrymal in front, and the ethmoid with the sphenoid behind. 
Outer or Lateral Wall (paries lateralis).-The outer wall is directed forward 
and inward, and is formed in front by the orbital process of the malar bone; 
behind, by the orbital surface of the greater wing of the sphenoid. On it are 
seen the orifices of one or two malar canals, and the suture connecting the sphenoid 
and malar bones. 
Angles.-The superior external angle is formed by the junction of the upper 
and outer walls; it presents from before backward, the suture connecting the 
frontal with the malar in front and with the great wing of the sphenoid behind; 
quite posteriorly is the foramen lacerum anterius, or sphenoidal fissure, which 
transmits the third, the fourth, the three branches of the ophthalmic division of 
the fifth, the sixth nerve, some filaments from the cavernous plexus of the sym- 
pathetic, the orbital branch of the middle meningeal artery, a recurrent branch 
from the lachrymal artery to the dura mater, and the ophthalmic vein. The 
superior internal angle is formed by the junction of the upper and inner wall, and 
presents the suture connecting the frontal bone with the lachrymal in front and 
with the ethmoid behind. The point of junction of the anterior border of the 
lachrymal with the frontal has been named the dacryon. This angle presents two 
foramina, the anterior and posterior ethmoidal foramina, the former transmitting the 
anterior ethmoidal vessels and nasal nerve, the latter the posterior ethmoidal vessels. 
The inferior external angle, formed by the junction of the outer wall and floor, pre- 
sents the spheno-maxillary fissure, which transmits the superior maxillary nerve and 
its orbital branches, the infraorbital vessels, and the ascending branches from the 
spheno-palatine or Meckel's ganglion. The inferior internal angle is formed by 
the union of the lachrymal bone and the os planum of the ethmoid with the 
superior maxillary and palate bones. 142 
THE SKELETON 
Circumference.-The circumference or base of the orbit, quadrilateral in form, 
is bounded above (margo supraorbitalis) by the supraorbital ridge; below (margo 
infraorbitalis), by the anterior border of the orbital plate of the malar and supe- 
rior maxillary bones; externally, by the external angular process of the frontal 
and malar bones; internally, by the internal angular process of the frontal and the 
nasal process of the superior maxillary. The circumference is marked by three 
sutures, the fronto-maxillary internally, the fronto-malar externally, and the malo- 
maxillary below; it contributes to the formation of the lachrymal groove, and 
presents, above, the supraorbital notch (or foramen), for the passage of the supra- 
orbital vessels and nerve. 
Apex.-The apex, situated at the back of the orbit, corresponds to the optic 
foramen,1 a short circular canal which transmits the optic nerve and ophthalmic 
artery. It will thus be seen that there are nine openings communicating with each 
orbit-viz., the optic foramen, sphenoidal fissure, spheno-maxillary fissure, supra- 
orbital foramen, infraorbital canal, anterior and posterior ethmoidal foramina, 
malar foramina, and the canal for the nasal duct. 
PROBE FROM FRONTAL 
SINUS IN THE 
INFUNDIBULUM 
DIBULUM 
-SITE OF ACTUAL OPENING 
OF MAXILLARY SINUS 
PROBE IN NASO- 
LACHRYMAL CANAL 
SEMILUNAR HIATUS 
PROBE FROM FRONTAL 
.SINUS IN THE INFUN- 
OPENING OF POSTERIOR 
ETHMOI DAL CELLS 
PROBE IN APERTURE OF 
SPHENOIDAL SINUS 
SPHENOPALATINE 
FORAMEN 
PROBE IN NASO- 
LACHRYMAL CANAL 
VERTICAL PLATE OF 
PALATE BONE 
Fig. 100.-Nasal cavity, right lateral wall, from the left. (Spalteholz.) 
The Nasal Cavity (cavurn nasi).-The nasal cavities or nasal fossae (Figs. 
84 and 100) are two large, irregular cavities situated on either side of the middle 
line of the face, extending from the base of the cranium to the roof of the 
mouth, and separated from each other by a thin vertical septum, the septum of 
the nose (septum nasi osseum), formed by the perpendicular plate of the ethmoid 
and by the vomer. Each cavity communicates by a large aperture, the anterior 
nasal aperture (apertura pyrijormis) with the front of the face, and by the two 
posterior nares (choana) with the naso-pharynx behind. These fossae are much 
1 Quain, Testut, and others give the apex of the orbit as corresponding with the inner end of the sphenoidal 
fissure. It seems better, however, to adopt the statement in the text, since the muscles of the eyeball take 
origin around the optic foramen, and diverge from it to the globe of the eye. 
2 In the skull freed of soft parts, the anterior nasal cavities open in front by the apertura pyriformis. In the 
skull with the soft parts in place they open by the antenoi nares THE ANTERIOR REGION OF THE SKULL 
143 
narrower above than below, and in the middle than at the anterior or posterior 
openings; their depth, which is considerable, is much greater in the middle than at 
either extremity. "The nasal fossae are surrounded by four other fossae-above is 
the cranial fossa; laterally, the orbital fossae; and below, the cavity of the mouth."1 
Each nasal fossa communicates with four sinuses, the frontal above, the sphenoidal 
behind, and the maxillary and ethmoidal on the outer wall. Each fossa also com- 
municates with four cavities: with the orbit by the lachrymal groove, with the 
mouth by the anterior palatine canal, with the cranium by the olfactory foramina, 
and with the spheno-m axillary fossa by the spheno-palatine foramen; and they occa- 
sionally communicate with each other by an aperture in the septum. The bones 
entering into their formation are fourteen in number: three of the cranium, the 
frontal, sphenoid, and ethmoid, and all the bones of the face, excepting the malar 
and lower jaw. Each cavity is bounded by a roof, a floor, an inner and an outer wall. 
Upper Wall.-The upper wall, or roof (Fig. 101), is long, narrow, and horizontal 
in its centre, but slopes downward at its anterior and posterior extremities; it is 
formed in front by the nasal bones and nasal spine of the frontal, which are 
directed downward and forward; in the middle, by the cribriform plate of the 
ethmoid, which is horizontal; and behind, by the under surface of the body of the 
sphenoid and sphenoidal turbinated bones, the ala of the vomer and the sphenoidal 
process of the palate bone, which are directed downward and backward. This 
surface presents, from before backward, the internal aspect of the nasal bones; 
on their outer side, the suture formed between the nasal bone and the nasal process 
of the superior maxillary; on their inner side, the elevated crest which receives the 
nasal spine of the frontal and the perpendicular plate of the ethmoid, and articu- 
lates with its fellow of the opposite side; whilst the surface of the bonesis perforated 
by a few small vascular apertures, and presents the longitudinal groove for the 
nasal nerve; farther back is the transverse suture, connecting the frontal with the 
nasal in front, and the ethmoid behind, the olfactory foramina and nasal slit on 
the under surface of the cribriform plate, and the suture between it and the sphe- 
noid behind; quite posteriorly are seen the sphenoidal turbinated bones, the ori- 
fices of the sphenoidal sinuses, and the articulation of the alae of the vomer with 
the under surface of the body of the sphenoid. 
Floor (Figs. 84, 100, and 101).- The floor is flattened from before backward, 
concave from side to side, and wider in the middle than at either extremity. It 
is formed in front by the palate process of the superior maxillary; behind, by the 
palate process of the palate bone. This surface presents, from before backward, 
the anterior nasal spine; behind this, the upper orifices of the anterior palatine canal; 
internally, the elevated crest which articulates with the vomer; and behind, the 
suture between the palate and superior maxillary bones, and the posterior nasal spine. 
Inner or Medial Wall.-The inner wall, or septum (Figs. 101 and 103), is a thin 
vertical partition which separates the nasal fossae from each other; it is occasionally 
perforated, so that the fossae communicate, and it is frequently deflected consid- 
erably to one side.2 It is formed, in front, by the crest of the nasal bones and 
nasal spine of the frontal; in the middle, by the perpendicular plate of the ethmoid; 
behind, by the vomer and rostrum of the sphenoid; below, by the crests of the 
superior maxillary and palate bones. It presents, in front, a large, triangular 
notch, which receives the septal cartilage of the nose; and behind, the grooved 
edge of the vomer. Its surface is marked by numerous vascular and nervous 
canals and the groove for the naso-palatine nerve, and is traversed by sutures 
connecting the bones of which it is formed. 
Outer or Lateral Wall.-The outer wall' (Figs. 84 and 101) is formed, in front, 
by the nasal process of the superior maxillary and lachrymal bones; in the middle, 
1 Howard A. Lothrop, in Annals of Surgery, May, 1903. 2 See footnote, p. 99. 144 
THE SKELETON 
by the ethmoid and inner surface of the body of the superior maxillary and inferior 
turbinated bones; behind, by the vertical plate of the palate bone and the internal 
pterygoid plate of the sphenoid. Upon this outer wall are two marked projections 
FRONTAL 
ETHMOID 
ORBIT 
UNCIFORM 
PROCESS OF 
ETHMOID 
MIDDLE 
TURBINATED 
INFERIOR 
TURBINATED 
I NF. 
MEATUS 
THIRD MOLAR 
tooth' 
Fig. 101.-Coronal section of the face, passing through the third molar tooth. (Poirier and Charpy.) 
of bone (Figs. 84 and 101). One is known as the inferior turbinated bone and the 
other as the middle turbinated bone. The superior turbinated bones or bodies appear 
BRISTLE PASSED THROUGH 
INFUNDIBULUM FROM 
FRONTAL SI NUS TO 
MIDDLE MEATUS 
IPROBE PASSED 
THROUGH LACH- 
RYMAL CANAL 
FRONTAL- 
SINUS 
"FRONTAL CANAL 
ANTRUM O F- 
MIGHMORE 
-NASAL CANAL 
Fig. 102.-Cranial section through the frontal sinus and nasal fossa. (Poirier and Charpy.) 
as less distinct bony projections. This surface presents three irregular longitudinal 
passages, or meatuses, termed the superior, middle, and inferior meatuses of the 
nose (Figs. 84, 101, and 102). The superior meatus (meatus nasi superior), the THE ANTERIOR REGION OF THE SKULL 
145 
smallest of the three, is situated at the upper and back part of each nasal fossa, occu- 
pying the posterior third of the outer wall. It is situated between the superior 
turbinated bone, and has opening into it two foramina, the spheno-palatine foramina 
at the back of its outer wall, and the posterior ethmoidal cells at the front part of 
the outer wall. The sphenoidal sinus opens into a recess, the spheno-ethmoidal 
recess (recessus sphenoethmoidalis), which is situated above and behind the 
superior turbinated bone. The middle meatus (meatus nasi medius) is situated 
external to the middle turbinated bone, and above the inferior turbinated bone, 
and extends from the anterior end of the inferior turbinated bone to the spheno- 
palatine foramen of the outer wall of the nasal fossa. Anteriorly it terminates in 
a depression, the atrium of the nasal meatus. The bulla ethmoidalis, an elevated 
area disclosed by removing the middle turbinated bone. Below and in front of the 
bulla is a groove, the semilunar hiatus (hiatus semilunaris), into which open the 
antrum and the anterior ethmoidal cells. The middle meatus presents in front 
the orifice of the infundibulum (infundibulum ethmoidale), by which the middle 
meatus communicates with the anterior ethmoidal cells, and through these with 
Rostrum of sphenoid. 
Crest of nasal bone. 
Nasal spine of 
frontal bone. 
Perpendicular plate 
of ethmoid. 
Space for triangular^ 
cartilage of septum. 
Vomer.' 
Crest of palate bone. 
.Crest of superior maxilla. 
Fig. 103.-Inner wall of nasal fossae, or septum of nose. 
the frontal sinuses. The middle ethmoidal cells also open into this meatus, while 
at the centre of the outer wall is the orifice of the maxillary antrum (hiatus maxil- 
laris), which varies somewhat as to its exact position in different skulls. The 
inferior meatus (meatus nasi inferior), the largest of the three, is the space between 
the inferior turbinated bone and the floor of the nasal fossa. It extends along 
the entire length of the outer wall of the nose, is broader in front than behind, 
and presents anteriorly the lower orifice of the canal for the nasal duct (canalis 
nasolacrimalis). The anterior nares present a heart-shaped or pyriform opening 
(apertura piriformis) whose long axis is vertical and narrow extremity upward. 
This opening in the recent state is much contracted by the cartilages of the nose. 
It is bounded above by the inferior border of the nasal bone; laterally by the thin, 
sharp margin which separates the facial from the nasal surface of the superior 146 
THE SKELETON 
maxillary bone; and below by the same border, where it slopes inward to join its 
fellow' of the opposite side at the anterior nasal spine. The posterior nares, or 
choanae, are the two posterior oval openings of the nasal fossae, by which they 
communicate with the upper part of the naso-pharynx. They are situated imme- 
diately in front of the basilar process, and are bounded above by the under 
surface of the body of the sphenoid and alte of the vomer; below, by the posterior 
border of the horizontal plate of the palate bone; externally, by the inner surface 
of the internal pterygoid plate; and internally, in the middle line, they are 
separated from each other by the posterior border of the vomer. 
Difference in Size and Form of the Cranium.-These differences are thus 
set forth by Mr. Arthur Thomson in Professor D. J. Cunningham's Text-book 
of Anatomy: 
Microcephalic skulls have a capacity of less than 1350 c.c. Mesocephalic skulls 
have a capacity of from 1350 c.c. to 1450 c.c. Megacephalic skulls have a capacity 
over 1450 c.c. 
What is known as the cephalic index is the proportion borne by the greatest 
breadth of the skull to the greatest length, assuming that the latter is equal to 100. 
Thomson gives the following formula: 
Maximum length X 100 , ,. . , 
* 7 j5 - = cephalic index, 
maximum breadth 
The cephalic index is used to determine the form of the skull: Dolichocephalic 
(long antero-posterior diameter) (Figs. 105 and 107), having a cephalic index 
Fig. 104.-Brachycephalic cranium. 
(Poirier and Charpy.) 
Fig. 105.-Dolichocephalic cranium. 
(Poirier and Charpy.) 
Fig. 106.-Brachycephalic cranium. 
(Poirier and Charpy.) 
Fig. 107.-Dolichocephalic cranium. 
Poirier and Charpy.) THE ANTERIOR REGION OF THE SKULL 
147 
below 75. Mesaticephalic (median head), having a cephalic index from 75 to 80. 
Brachycephalic (short antero-posterior diameter) (Figs. 104 and 106), having a 
cephalic index over 80. 
Surface Form.-The various bony prominences or landmarks which are to be easily felt and 
recognized in the head and face, and which afford the means of mapping out the important 
structures comprised in this region, are as follows: 
1. Supraorbital arch. 
2. Internal angular process. 
3. External angular process. 
4. Zygomatic arch. 
5. Mastoid process. 
6. External occipital protuberance. 
7. Superior curved line of occipital bone. 
8. Parietal eminences. 
9. Temporal ridge. 
10. Frontal eminences. 
11. Superciliary ridges. 
12. Nasal bones. 
13. Lower margin of orbit. 
14. Lower jaw. 
1. The supraorbital arches are to be felt throughout their entire extent, covered by the eye- 
brows. They form the upper boundary of the circumference or base of the orbit, and separate 
the face from the forehead. They are strong and arched, and terminate internally on each side 
of the root of the nose in the internal angular process, which articulates with the lachrymal 
bone. Externally they terminate in the external angular process, which articulates with the 
malar bone. This arched ridge is sharper and more defined in its outer than in its inner half, 
and forms an overhanging process which protects and shields the lachrymal gland. It thus pro- 
tects the eye in its most exposed situation and in the direction from which blows are most likely 
to descend. The supraorbital arch varies in prominence in different individuals. It is more 
marked in the male than in the female, and in some races of mankind than others. In the less 
civilized races, as the forehead recedes backward, the supraorbital arch becomes more prominent, 
and approaches more to the characters of the monkey tribe, in which the supraorbital arches are 
very largely developed, and acquire additional prominence from the oblique direction of the 
frontal bone. 2. The internal angular process is scarcely to be felt. Its position is indicated 
by the angle formed by the supraorbital arch with the nasal process of the superior maxillary 
bone and the lachrymal bone at the inner side of the orbit. Between the internal angular pro- 
cesses of the two sides is a broad surface which assists in forming the root of the nose, and 
immediately above this a broad, smooth, somewhat triangular surface, the glabella, situated 
between the superciliary ridges. 3. The external angular process is much more strongly marked 
than the internal, and is plainly to be felt. It is formed by the junction or confluence of the supra- 
orbital and temporal ridges, and, articulating with the malar bone, it serves to a very consider- 
able extent to support the bones of the face. In carnivorous animals the external angular pro- 
-cess does not articulate with the malar, and therefore this lateral support to the bones of the face 
is not present. 4. The zygomatic arch is plainly to be felt throughout its entire length, being 
situated almost immediately under the skin. It is formed by the malar bone and the zygomatic 
process of the temporal bone. At its anterior extremity, where it is formed by the malar bone, 
it is broad and forms the prominence of the cheek; the posterior part is narrower, and termi- 
nates just in front and a little above the tragus of the external ear. The lower border is 
more plainly to be felt than the upper, in consequence of the dense temporal fascia being 
attached to the latter, which somewhat obscures its outline. Its shape differs very much in indi- 
viduals and in different races of mankind. In the most degraded type of skull-as, for instance, 
in the skull of the negro of the Guinea Coast-the malar bones project forward and not outward, 
and the zygoma at its posterior extremity extends farther outward before it is twisted on itself to 
be prolonged forward. This makes the zygomatic arch stand out in bold relief, and affords 
greater space for the Temporal muscle. In skulls which have a more pyramidal shape, as in the 
Esquimaux or Greenlander, the malar bones do not project forward and downward under the 
eyes, as in the preceding form, but take a direction outward, forming with the zygoma a large, 
rounded sweep or segment of a circle. Thus it happens that if two lines are drawn from the 
zygomatic arches, touching the temporal ridges, they meet above the top of the head, instead of 
being parallel, or nearly so, as in the European skull, in which the zygomatic arches are not 
nearly so prominent. This gives to the face a more or less oval type. 5. Behind the ear is the 
mastoid portion of the temporal bone, plainly to be felt, and terminating below in a nipple- 
shaped process. Its anterior border can be traced immediately behind the concha, and its apex 
is on about a level with the lobule of the ear. It is rudimentary in infancy, but gradually 
develops in childhood, and is more marked in the negro than in the European. 6. The external 
occipital protuberance is always plainly to be felt just at the level where the skin of the neck 
joins that of the head. At this point the skull is thick for the purposes of safety, while radiating 
from it are numerous curved arches or buttresses of bone which give to this portion of the 
skull further security. 7. Running outward on either side from the external occipital protu- 
berance is an arched ridge of bone, which can be more or less plainly perceived. This is the 
superior curved line of the occipital bone, and gives attachment to some of the muscles which 148 
THE SKELETON 
keep the head erect on the spine; accordingly, we find it more developed in the negro tribes, in 
whom the jaws are much more massive, and therefore require stronger muscles to prevent their 
extra weight carrying the head forward. Below this line the surface of bone at the back of the 
head is obscured by the overlying muscles. Above it, the vault of the cranium is thinly covered 
with soft structures, so that the form of this part of the head is almost exactly that of the upper 
portion of the occipital, the parietal, and the frontal bones themselves; and in bald persons, 
even the lines of junction of the bones, especially the junction of the occipital and parietal at 
the lambdoid suture, may be defined as a slight depression, caused by the thickening of the 
borders of the bones in this situation. 8. In the line of the greatest transverse diameter of the 
head, on each side of the middle line, are generally to be found the parietal eminences, one on 
each side of the middle line, though sometimes these eminences are not situated at the point of 
the greatest transverse diameter, which is at some other prominent part of the parietal region. 
They denote the point where ossification of the parietal bone began. They are much more 
prominent and well-marked in early life, in consequence of the sharper curve of the bone at 
this period, so that it describes the segment of a smaller circle. Later in life, as the bone grows, 
the curve spreads out and forms the segment of a larger circle, so that the eminence becomes 
less distinguishable. In consequence of this sharp curve of the bone in early life, the whole of 
the vault of the skull has a squarer shape than it has in later life, and this appearance may per- 
sist in some rickety skulls. The eminence is more apparent in the negro's skull than in that of 
the European. This is due to greater flattening of the temporal fossa in the former skull to 
accommodate the larger Temporal muscle which exists in these races. The parietal eminence 
is particularly exposed to injury from blows or falls on the head, but fracture is to a certain 
extent prevented by the shape of the bone, which forms an arch, so that the force of the blow 
is diffused over the bone in every direction. 9. At the side of the head may be felt the temporal 
ridge. Commencing at the external angular process, it may be felt as a curved ridge, passing 
upward and then curving backward, on the frontal bone, separating the forehead from the 
temporal fossa. It may then be traced passing backward in a curved direction, over the parietal 
bone, and, though less marked, still generally to be recognized. Finally, the ridge curves down- 
ward, and terminates in the posterior root of the zygoma, which separates the squamous from 
the subcutaneous mastoid portion of the temporal bone. Sir Victor Horsley has recently shown 
in an article on the "Topography of the Cerebral Cortex," that the second temporal ridge (see 
page 76) can be made out on the living body. 10. The frontal eminences varya good deal in 
different individuals, being considerably more prominent in some than in others, and they are 
often not symmetrical on the two sides of the body, the one being much more pronounced than 
the other. This is often especially noticeable in the skull of the young child or infant, and 
becomes less marked as age advances. The prominence of the frontal eminences depends 
more upon the general shape of the whole bone than upon the size of the protuberances them- 
selves. As the skull is more highly developed in consequence of increased intellectual capacity, 
so the frontal bone becomes more upright and the frontal eminences stand out in bolder relief. 
Thus they may be considered as affording, to a certain extent, an indication of the development 
of the hemispheres of the brain beneath, and of the mental powers of the individual. They 
are not so much exposed to injury as the parietal eminences. In falls forward the upper extrem- 
ities are involuntarily thrown out, and break the force of the fall, and thus shield the frontal 
bone from injury. 11. Below the frontal eminences on the forehead are the superciliary ridges, 
which denote the position of the frontal sinuses, and vary according to the size of the sinuses 
in different individuals, being, as a rule, small in the female, absent in children, and some- 
times unusually prominent in the male, when the frontal sinuses are largely developed. They 
commence on either side of the glabella, and at first present a rounded form, which gradually 
fades away at their outer ends. 12. The nasal bones form the prominence of the nose. They 
vary much in size and shape, and to them is due the varieties in the contour of this organ and 
much of the character of the face. Thus, in the Mongolian or Ethiopian they are flat, broad^ 
and thick at their base, giving to these races the flattened nose by which they are characterized, 
and differing very decidedly from the Caucasian, in whom the nose, owing to the shape of the 
nasal bones, is narrow, elevated at the bridge, and elongated downward. Below, the nasal 
bones are thin and connected with the cartilages of the nose, and the angle or arch formed by 
their union serves to throw out the bridge of the nose, and is much more marked in some indi- 
viduals than others. 13. The lower margin of the orbit, formed by the superior maxillary bone 
and the malar bone, is plainly to be felt throughout its entire length. It is continuous inter- 
nally with the nasal process of the superior maxillary bone, which forms the inner boundary 
of the orbit. At the point of junction of the lower margin of the orbit with the nasal process 
is to be felt a little tubercle of bone, which can be plainly perceived by running the finger along 
the bone in this situation. This tubercle serves as a guide to the position of the lachrymal sac, 
which is situated above and behind it. 14. The outline of the lower jaw is to be felt throughout 
its entire length. Just in front of the tragus of the external ear, and below the zygomatic arch, 
the condyle can be made out. When the mouth is opened this prominence of bone can be per- 
ceived advancing out of the glenoid fossa on to the eminentia articularis, and receding again THE ANTERIOR REGION OF THE SKULL 
149 
when the mouth is closed. From the condyle the posterior border of the ramus can be felt 
extending down to the angle. A line drawn from the condyle to the angle would indicate the 
exact position of this border. From the angle to the symphysis of the chin the lower, rounded 
border of the body of the bone is plainly to be felt. At the point of junction of the two halves 
of the bone is a well-marked triangular eminence, the mental process, which forms the promi- 
nence of the chin. 
Fixed Points for Measurement.-In order to determine the location of regions of surgical 
importance within the skull (bony spaces, vessels, fissures, centres, and convolutions of the 
brain) and in order to estimate cranial capacity, measurements are made and these measure- 
ments are taken from fixed points. The following are the chief fixed points: 
The Nasion. The middle of the naso-frontal suture. 
The Glabella. Midway between the two superciliary ridges. 
The Obelion. A point in the sagittal suture between the parietal foramina. 
The Inion. The external occipital protuberance. 
The Basion. The middle of the anterior edge of the foramen magnum. 
The Opisthion. The middle of the posterior edge of the foramen magnum. 
The Lambda. The point of junction of the sagittal and lambdoid sutures. 
The Pterion. The site of the antero-lateral fontanelle, where the frontal, parietal, squa- 
mous portion of the temporal and greater wing of the sphenoid are in relation. 
The Asterion. The region of the postero-lateral fontanelle, at the posterior inferior margin 
of the parietal bone. 
The Bregma. The site of the anterior fontanelle, where the sagittal and coronal sutures 
meet. 
The Superior Stephanion. The point where the superior temporal ridge meets the coronal 
suture. 
The Inferior Stephanion. The point where the inferior temporal ridge meets the coronal 
suture. 
The Gonion. The outer surface of the angle of the mandible. 
The Ophryon. The middle of the narrowest transverse diameter of the forehead. 
The Vertex. The highest point of the vault of the skull. 
Besides these points we use the mastoid process, the nasal spine, the zygomatic arch, the 
frontal eminences, the parietal eminences, the supraorbital ridges, the superciliary ridges, the 
mental process, suprameatal spine, the external and internal angular processes, and the canine 
fossa. 
Surgical Anatomy.-The thickness of the skull varies greatly in different regions of the same 
skull and in different individuals. The average thickness of the skull-cap is about one-fifth 
of an inch. The thickest portions are the occipital protuberance, the inferior portion of the 
frontal bone, and the mastoid process. The thinnest portions are the occipital fossae, the squa- 
mous portion of the temporal bone, and over certain sinuses and arteries. An arrest in the 
ossifying process may give rise to deficiencies or gaps, or to fissures, which are of importance 
in a medico-legal point of view, as they are liable to be mistaken for fractures. The fissures 
generally extend from the margin toward the centre of the bone, but gaps may be found in the 
middle as well as at the edges. In course of time they may become covered with a thin lamina 
of bone. 
Occasionally a protrusion of the brain or its membranes may take place through one of these 
gaps in an imperfectly developed skull. When the protrusion consists of membranes only, and 
is filled with cerebro-spinal fluid, it is called a meningocele ; when the protrusion consists of brain 
as well as membranes, it is termed an encephalocele and when the protruded brain is a prolonga- 
tion from one of the ventricles, and is distended by a collection of fluid from an accumulation in 
the ventricle, it is termed an hydrencephalocele. This latter condition is sometimes found at the 
root of the nose, where a protrusion of the anterior horn of the lateral ventricle takes place 
through a deficiency of the fronto-nasal suture. These malformations are usually found in the 
middle line, and most frequently at the back of the head, the protrusion taking place through 
the fissures which separate the four centres of ossification from which the tabular portion of the 
occipital bone is originally developed (see page 75). They most frequently occur through the 
upper part of the vertical fissure, which is the last to ossify, but not uncommonly through the 
lower part, when the foramen magnum may be incomplete. More rarely these protrusions 
have been met with in other situations than those above mentioned, both through normal 
fissures, as the sagittal, lambdoid, and other sutures, and also through abnormal gaps and 
deficiencies at the sides, and even at the base of the skull. Force may be responsible in a young 
person for separating a suture. This accident, seldom met with even in the young, is only occa- 
sionally encountered in older persons. 
Fractures of the skull may be divided into those of the vault and those of the base. Frac- 
tures of the vault are usually produced by direct violence. This portion of the skull varies in 
thickness and strength in different individuals, but, as a rule, is sufficiently strong to resist a very 
considerable amount of violence without being fractured. This is due to several causes: the 150 
THE SKELETON 
rounded shape of the head and its construction of a number of secondary elastic arches, each 
made up of a single bone; the fact that it consists of a number of bones, united, at all events in 
early life, by a sutural ligament, which acts as a sort of buffer and interrupts the continuity of 
any violence applied to the skull; the presence of arches or ridges, both on the inside and outside 
of the skull, which materially strengthen it; and the mobility of the head upon the spine, which 
further enables it to withstand violence. The elasticity of the bones of the head is especially 
marked in the skull of the child, and this fact, together with the wide separation of the indi- 
vidual bones from each other, and the interposition between them of other and softer structures 
render fracture of the bones of the head a very uncommon event in infants and quite young 
children; as age advances and the bones become joined, fracture is more common, though still 
less liable to occur than in the adult. Fractures of the vault may, and generally do, involve the 
whole thickness of the bone; but sometimes one table may be fractured without any correspond- 
ing injury to the other. Thus, the outer table of the skull may be splintered and driven into the 
diploe, or in the frontal or mastoid regions into the frontal or mastoid cells, without any injury 
to the internal table. And on the other hand, the internal table has been fractured, and por- 
tions of it depressed and driven inward, without any fracture of the outer table. As a rule, in 
fractures of the skull the inner table is more splintered and comminuted than the outer, and 
this is due to several causes. It is thinner and more brittle; the force of the violence as it passes 
inward becomes broken up, and is more diffused by the time it reaches the inner table; the 
bone, being in the form of an arch, bends as a whole and spreads out, and thus presses the 
particles together on the convex surface of the arch-i. e., the outer table-and forces them 
asunder on the concave surface or inner table; and, lastly, there is nothing firm under the inner 
table to support it and oppose the force. Fractures of the vault may be simple fissures or starred 
and comminuted fractures, and these may be depressed or elevated. These latter cases of 
fracture with elevation of the fractured portion are uncommon, and can only be produced by 
direct wound. In comminuted fracture a portion of the skull is broken into several pieces, 
the lines of fracture radiating from a centre where the chief impact of the blow was felt; if 
depressed, a fissure circumscribes the radiating line, enclosing a portion of skull. If this area 
is circular, it is termed a pond fracture, and would in all probability have been caused by 
a round instrument, as a life-preserver or hammer; if elliptical in shape, it is termed a gutter 
fracture, and would owe its shape to the instrument which had produced it, as a poker. A 
fracture may take place along the line of an ossified or partly ossified suture. When a surgeon 
explores the vault of the skull through a wound he must not mistake a Wormian bone for a frag- 
ment produced by a fracture. A Wormian bone which may lead to mistake is encountered at 
the anterior inferior angle of the parietal bone. Wormian bones are most frequently found 
along the lambdoid suture. 
Fractures of the base are most frequently produced by the extension of a fissure from the 
vault, as in falls on the head, where the fissure starts from the part of the vault which first 
struck the ground. Sometimes, however, they are caused by direct violence, when foreign 
bodies have been forced through the thin roof of the orbit, through the cribriform plate of the 
ethmoid from being thrust up the nose, or through the roof of the pharynx. Other cases of 
fracture of the base occur from indirect violence, as in fracture of the occipital bone from impac- 
tion of the spinal column against its condyles in falls on the buttocks, knees, or feet, or in cases 
where the glenoid cavity has been fractured by the violent impact of the condyle of the lower jaw 
against it from blows on the chin. 
The most common place for fracture of the base to occur is through the middle fossa, and 
here the fissure usually takes a fairly definite course. Starting from the point struck, which is 
generally somewhere in the neighborhood of the parietal eminence, it runs downward through the 
parietal bone and the squamous portion of the temporal bone and across the petrous portion of this 
bone, frequently traversing and implicating the internal auditory meatus, to the middle lacerated 
foramen. From this it may pass across the body of the sphenoid, through the pituitary fossa to 
the middle lacerated foramen of the other side, and may indeed travel round the whole cranium, 
so as to completely separate the anterior from the posterior part. The course of the fracture 
should be borne in mind, as it explains the symptoms to which fracture in this region may give 
rise; thus, if the fissure pass across the internal auditory meatus, injury to the facial and auditory 
nerves may result, with consequent facial paralysis and deafness; or the tubular prolongation 
of the arachnoid around these nerves in the meatus may be torn, and thus permit of the escape 
of the cerebro-spinal fluid should there be a communication between the internal ear and the 
tympanum and the membrana tympani be ruptured, as is frequently the case; again, if the 
fissure passes across the pituitary fossa and the muco-periosteum covering the under surface 
of the body of the sphenoid is torn, blood will find its way into the pharynx and be swallowed, 
and after a time vomiting of blood will result. Fractures of the anterior fossa, involving the 
bones forming the roof of the orbit and nasal fossa, are generally the results of blow's on the fore- 
head; but fracture of the cribriform plate of the ethmoid may be a complication of fracture of 
the nasal bone. When the fracture implicates the roof of the orbit, the blood finds its way 
into this cavity, and, travelling forward, appears as a subconjunctival ecchymosis. Subcon- THE ANTERIOR REGION OF THE SKULL 
151 
junctival ecchymosis can also be caused by fracture of the malar bone. If the roof of the nasal 
fossa be fractured, the blood escapes from the nose. In rare cases there may be also escape of 
cerebro-spinal fluid from the nose where the dura mater and arachnoid have been torn. In 
fractures of the posterior fossa extravasation of blood takes place beneath the deep fascia and 
discoloration of the skin is soon observed in the course of the posterior auricular artery, the dis- 
coloration first appearing in the skin over the tip of the mastoid process of the temporal bone 
(Battle's sign). Some of the blood which was extravasated beneath the deep fascia approaches 
the surface through the openings in the deep fascia for the passage of vessels and nerves. 
The bones of the skull are frequently the seat of nodes, and not uncommonly necrosis results 
from this cause, also from injury. Necrosis may involve the entire thickness of the skull, but 
is usually confined to the external table. Necrosis of the internal table alone is rarely met with. 
The bones of the skull are also sometimes the seat of sarcomatous tumor. 
The skull in rickets is peculiar: the forehead is high, square, and projecting, and the antero- 
posterior diameter of the skull is long in relation to the transverse diameter. The bones of the 
face are small and ill-developed, and this gives the appearance of a larger head than actually 
exists. The bones of the head are often thick, especially in the neighborhood of the sutures, 
and the anterior fontanelle is late in closing, sometimes remaining unclosed till the fourth year. 
The condition of craniotabes has by some been also believed to be the result of rickets, by others 
is believed to be due to inherited syphilis. In all probability it is due to both. In these cases 
the bone undergoes atrophic changes in patches, so that it becomes greatly thinned in places, 
generally where there is pressure, as from the pillow or nurse's arm. It is, therefore, usually 
met with in the parietal bone and vertical plate of the occipital bone. 
In congenital syphilis deposits of porous bone are often found at the angles of the parietal 
bones and two halves of the frontal bone which bound the anterior fontanelle. These deposits 
are separated by the coronal and sagittal sutures, and give to the skull an appearance like a hot 
cross bun. They are known as Parrot's nodes, and such a skull has received the name of nati- 
form, from its fancied resemblance to the buttocks. When the surgeon wishes to effect an entrance 
into the interior of the mastoid antrum (Fig. 108) he applies his bur or gouge in the suprameatal 
triangle 1 cm. posterior to the suprameatal spine, being careful to keep below the posterior root of 
the zygoma and the level of the superior wall of the bony meatus. If the instrument is entered 
at a higher level it will open the cerebral cavity; the instrument should be carried inward, for- 
ward, and a little upward, that is, in the direction of the auditory canal. The antrum is usually 
reached after the penetration of from 1 to 1J cm. of bone. The depth at which the antrum is sit- 
uated is not constant. "It is safe to say that if the instrument penetrates deeper than 1 j cm. and 
be directed too far forward or downward, the horizontal semicircular canal or the aquaeductus 
Fallopii will be encountered. If the 
former were opened in a purulent otitis 
media the pus would travel along it to 
the vestibule and from there into the 
internal auditory meatus, producing a 
pachymeningitis or extradural (epidural) 
abscess of the posterior fossa of the skull; 
or from the vestibule through the perpen- 
dicular semicircular canal, which if ac- 
companied by erosion of its bony cover- 
ing would lead to involvement of the 
meninges of the middle fossa; the same 
would hold good for the posterior semi- 
circular canal, affecting the posterior 
fossa. If the latter (the aquteductus Fal- 
lopii) were opened an inflammation of 
the facial nerve which is contained there- 
in would result, producing paralysis of 
that side of the face. The inflammatory 
process might also find its way through 
the entire canal to the internal auditory 
meatus, causing a pachymeningitis or 
extradural abscess as mentioned above; 
or, travelling along the nerve to its cere- 
bral attachment, would produce a men- 
ingitis or subdural (intradural) abscess. 
The direction of the penetrating instru- 
ment must also be forward, in order to avoid injuring the lateral cinus" ("Anatomy and Sur- 
gery of the Temporal Bone," by A. E. Schmitt, M.D., American Journal oj the Medical Sciences, 
April, 1903). In the operation for infective thrombosis of the lateral sinus the sinus is deliber- 
ately exposed and opened (Fig. 108). 
Fig. 108.-Division of the mastoid process into four equal 
parts. An opening in the upper anterior quadrant reaches the 
mastoid antrum ; into the upper posterior quadrant reaches 
the lateral sinus ; the lower anterior quadrant into mastoid 
cells ; a superficial opening into the lower posterior quadrant 
reaches mastoid cells ; a deep opening reaches the descending 
limb of the lateral sinus. (A. E. Schmitt.) THE SKELETON 
152 
Hartley divides the mastoid process into four parts as follows: The upper margin is the 
posterior root of the zygoma. The anterior margin is the anterior border of the mastoid. The 
posterior margin is a vertical line dropped from the masto-occipital junction. The lower mar- 
gin is an imaginary line backward from the mastoid tip. This space is divided into four equal 
parts. Points upon it may be designated as on a map. Take the left side for demonstration. 
An opening in the N. W. quadrant enters the antrum, one into the N. E. quadrant exposes the 
lateral sinus, one into the S. W. quadrant enters mastoid cells, and a superficial one into the 
S. E. quadrant enters mastoid cells, but a deep one exposes the descending portion of the lateral 
sinus. 
When pus breaks through the mastoid process it may enter the sheath of the digastric or sterno- 
cleido-mastoid muscle and point a considerable distance away from the bone, Bezold's abscess. 
In connection with the bones of the face a common malformation is cleft palate, owing to 
the non-union of the palatal processes of the maxillary or pre-oral arch. This cleft may involve 
the whole or only a portion of the hard palate, and usually involves the soft palate also. The 
cleft is in the middle line, except it involves the alveolus in front, when it follows the suture 
between the main portion of the bone and the pre-maxillary bone. Sometimes the cleft runs 
on either side of the pre-maxillary bone, so that this bone is quite isolated from the maxillary 
bones and hangs from the end of the vomer. In such a case the pre-maxillary bone usually 
contains the germs of the central incisors only. In some cases there is no pre-maxillary bone 
and the great gap in the lip is in the median line. Cleft palate (Fig. 92) is usually associated 
with hare-lip, which, when single, is almost always on one side, corresponding to the position 
of the suture between the lateral incisor and canine tooth. Some few cases of median hare- 
lip have been described. In double hare-lip there is a cleft on each side of the middle line (see 
page 111). 
The outlines and the height of the arch of the palate vary greatly in different persons. A 
narrow palate with a high arch is common in idiots and certain degenerates. 
The bones of the face are sometimes fractured as the result of direct violence. The two 
most commonly broken are the nasal bone and the mandible, and of these the latter is by 
far the most frequently fractured of all the bones of the face. Fracture of the nasal bone is 
for the most part transverse, and takes place about half an inch from the free margin. The 
broken portion may be displaced backward or more generally to one side by the force which 
produced the lesion, as there are no muscles here which can cause displacement. The malar 
bone is probably never broken alone; that is to say, unconnected with a fracture of the other 
bones of the face. The zygomatic arch is occasionally fractured, and when this occurs from 
direct violence, as is usually the case, the fragments may be displaced inward. This lesion is 
often attended with great difficulty or even inability to open and shut the mouth, and this has 
been stated to be due to the depressed fragments perforating the temporal muscle, but would 
appear rather to be caused by the injury done to the bony origin of the Masseter muscle. 
Fractures of the superior maxilla may vary much in degree, from the chipping off of a portion 
of the alveolar arch, a frequent accident when the "old key" instrument was used for the 
extraction of teeth, to an extensive comminution of the whole bone from severe violence, as 
the kick of a horse. The most common situation for a fracture of the mandible bone is in the 
neighborhood of the canine tooth, as at this spot the jaw is weakened by the deep socket for 
the fang of this tooth; it is next most frequently fractured at the angle; then at the symphysis, 
and finally the neck of the condyle or the coronoid process may be broken. Occasionally a 
double fracture may occur, one in either half of the bone. The fractures are usually compound, 
from laceration of the mucous membrane covering the gums. The displacement is mainly the 
result of the same violence as produced the injury, but may be further increased by the action 
of the muscles passing from the neighborhood of the symphysis to the hyoid bone. 
The superior and inferior maxillary bones are both of them frequently the seat of necrosis, 
though the disease affects the lower much more frequently than the upper jaw. It may be the 
result of periostitis, from tooth irritation, injury, or the action of some specific poison, as syphilis, 
or from salivation by mercury; it not infrequently occurs in children after attacks of the exan- 
thematous fevers, and a special form occurs from the action of the fumes of phosphorus in 
persons engaged in the manufacture of matches. 
Tumors attack the jaw bones not infrequently, and these may be either innocent or malig- 
nant: in the upper jaw cysts may occur in the antrum, constituting the so-called dropsy of the 
antrum; or, again, cysts may form in either jaw in connection with the teeth: either cysts con- 
nected with the roots of fully developed teeth, the "dental cyst;" or cysts connected with im- 
perfectly developed teeth, the "dentigerous cyst." Solid innocent tumors include the fibroma, 
the chondroma, and the osteoma. Of malignant tumors there are the endotheliomata, the 
sarcomata, and the epitheliomata. The sarcomata are of various kinds, the spindle-celled, 
the round-celled, which are of a very malignant character, and the myeloid sarcomata, prin- 
cipally affecting the alveolar margin of the bone. Of the epitheliomata we find the squamous 
variety spreading to the bone from the palate or gum, and the cylindrical epithelioma origin- 
ating in the antrum or nasal fossae. THE HYOID OR LINGUAL BONE 
153 
Both superior and inferior maxillary bones occasionally require excision for tumors and in 
some other conditions. The upper jaw is removed by an incision from the inner canthus of the 
eye, along the side of the nose, round the ala, and down the middle line of the upper lip. A 
second incision is carried outward from the inner canthus of the line along the lower margin of 
the orbit as far as the prominence of the malar bone. The flap thus formed is reflected outward 
and the surface of the bone exposed, and the central incisor of the diseased side is removed. 
The connections of the bone to the other bones of the face are then divided with a narrow saw and 
bone-cutting forceps. They are (1) the junction with the malar bone, passing into the spheno- 
maxillary fissure; (2) the nasal process; a small portion of its upper extremity, connected with the 
nasal bone in front, the lachrymal bone behind, and the frontal bone above, being left; (3) the 
connection with the bone on the opposite side and the palate in the roof of the mouth. The 
bone is now firmly grasped with lion-jaw forceps, and by means of a rocking movement upward 
and downward the remaining attachments of the orbital plate with the ethmoid and the 
back of the bone with the palate, broken through. The soft palate is first separated from 
the hard with a scalpel, and is not removed. Occasionally in removing the upper jaw it 
will be found that the orbital plate can be spared, and this should always be done if possible. 
A horizontal saw-cut is to be made just below the infraorbital foramen and the bone cut through 
with a chisel and mallet. Lockwood has pointed out that in removing the upper jaw the sur- 
geon must be careful in dividing the nasal process of the superior maxilla to preserve the inter- 
nal orbital or palpebral ligament (Tendo oculi), because this ligament arises from the palpebral 
fascia, and if it is interfered with the eye will inevitably drop downward. Removal of one-half 
of the lower jaw is sometimes required. If possible, the section of the bone should be made 
to one side of the symphysis, so as to save the genial tubercles and the origin of the genio-hyo- 
glossus muscle, as otherwise the tongue tends to fall backward and may produce suffocation. 
Having extracted the central or preferably the lateral incisor tooth, a vertical incision is made 
down to the bone, commencing at the free margin of the lip, and carried to the lower border 
of the bone; it is then carried along its lower border to the angle and up the posterior margin 
of the ramus to a level with the lobule of the ear. The flap thus formed is raised by separating 
all the structures attached to the outer surface of the bone. The jaw is now sawn through 
at the point where the tooth has been extracted, and the knife passed along the inner side of 
the jaw, separating the structures attached to this surface. The jaw is then grasped by the 
surgeon and strongly depressed, so as to bring down the coronoid process and enable the operator 
to sever the tendon of the Temporal muscle. The jaw can be now further depressed, care being 
taken not to evert it nor rotate it outward, which would endanger the internal maxillary artery, 
and the External pterygoid muscle is torn through or divided. The capsular ligament is now 
opened in front and the lateral ligaments divided, and the jaw removed with a few final touches 
of the knife. 
The antrum of Highmore occasionally requires tapping for suppuration. This may be done 
through the socket of a tooth, preferably the first molar, the fangs of which are most intimately 
connected with the antrum, or through the facial aspect of the bone above the alveolar process. 
This latter method does not perhaps afford such efficient drainage, but there is less chance of 
food finding its way into the cavity. The operation may be performed by incising the mucous 
membrane above the second molar tooth, and driving a trocar or any sharp-pointed instrument 
into the cavity. 
THE HYOID OR LINGUAL BONE (OS HYOIDEUM). 
The hyoid bone (Fig. 109) is named from its resemblance to the Greek upsilon; 
it is also called the lingual hone, because it supports the tongue and gives attach- 
ment to its numerous muscles. It is a bony arch, shaped like a horseshoe, and 
consisting of five segments: a body, two greater cornua, and two lesser cornua. It 
is suspended from the tip of the styloid processes of the temporal bone by liga- 
mentous bands, the stylo-hyoid ligaments. 
Body {corpus ossei hyoidei}.-The body, or basi-hyal, forms the central part 
of the bone, and is of a quadrilateral form. 
Surfaces.-Its anterior surface (Fig. 109), convex, directed forward and upward, 
is divided into two parts by a vertical ridge which descends along the median 
line and is crossed at right angles by a horizontal ridge, so that this surface is 
divided into four spaces or depressions. At the point of meeting of these two lines 
is a prominent elevation, the tubercle. The portion above the horizontal ridge is 
directed upward, and is sometimes described as the superior border. The anterior 
surface gives attachment to the Genio-hyoid in the greater part of its extent; above, 154 
THE SKELETON 
to the Genio-hyo-glossus; below, to the Mylo-hyoid, Stylo-hyoid, and aponeurosis of 
the Digastric (suprahyoid aponeurosis); and between these to part of the Hvo- 
glossus. The posterior surface is smooth, concave, directed backward and down- 
ward, and separated from the epiglottis by the thyro-hyoid membrane and by a 
quantity of loose areolar tissue. The lateral surfaces after middle life are joined 
to the greater cornua. In early life they are connected to the cornua by carti- 
laginous surfaces, and held together by ligaments, and occasionally a synovial 
membrane is found between them. 
Borders.-The superior border is rounded, and gives attachment to the thvro- 
hyoid membrane, part of the Genio-hyo-glossi and Chondro-glossi muscles. The 
inferior border gives attachment, in front, to the Sterno-hyoid; behind, to the Omo- 
hyoid and to the part of the Thyro- 
hyoid at its junction with the great 
cornu. It also gives attachment to 
the Levatore glanduhe thyroideae 
when this muscle is present. 
Greater Cornuafcornwa majord). 
-The greater cornua or thyro-hyals 
project backward from the lateral 
surfaces of the body; they are flat- 
tened from above downward, di- 
minish in size from before back- 
ward, and terminate posteriorly in 
a tubercle for the attachment of 
the lateral thyro-hyoid ligament. 
The outer surface gives attachment 
to the Hyo-glossus, their upper border to the Middle constrictor of the pharynx, 
their lower border to part of the Thyro-hyoid muscle. 
Lesser Cornua (cornua minora).-The lesser cornua, or cerato-hyals, are two 
small, conical-shaped eminences attached by their bases to the angles of junc- 
tion between the body and greater cornua, and giving attachment by their apices 
to the stylo-hyoid ligaments.1 The smaller cornua are connected to the body of 
the bone by a distinct diarthrodial joint, which usually persists throughout life, 
but occasionally becomes ankylosed. 
Development.-By five centres: one for the body, and one for each cornu. 
Ossification commences in the body about the eighth month, and in the greater 
cornua toward the end of festal life. Ossification of the lesser cornua commences 
some years after birth. Sometimes there are two centres for the body. 
Attachment of Muscles.-Sterno-hyoid, Thyro-hyoid, Omo-hyoid, aponeurosis 
of the Digastric, Stylo-hyoid, Mylo-hyoid, Genio-hyoid, Genio-hyo-glossus, Chon- 
dro-glossus, Hyo-glossus, Middle constrictor of the pharynx, and occasionally a 
few fibres of the Inferior lingualis. It also gives attachment to the thyro-hyoidean 
membrane and the stylo-hyoid, thyro-hyoid, and hyo-epiglottic ligaments. 
Greater Cornu. 
middle constrictor of Pharynx.' 
HYO-GLOSSUS.s 
Lesser Cornu. 
CHONDRO- 
GLOSSUS. 
GENIO-HYO-GLOSSUS. 
THYRO-HYOID 
Body. 
STYLO-HYOID. 
OMO-HYOlD. 
QENJO-HYOID 
STERNO-HYOID. 
MYLO-HYOID. 
Fig. 109.-Hyoid bone. Anterior surface. (Enlarged.) 
Surface Form.-The hyoid bone can be felt in the receding angle below the chin, and the 
finger can be carried along the whole length of the bone to the greater cornu, which is situated 
just below the angle of the jaw. This process of bone is best perceived by making pressure on 
one cornu, and so pushing the bone over to the opposite side, when the cornu of this side will 
be distinctly felt immediately beneath the skin. This process of bone is an important landmark 
in ligature of the lingual artery. 
Surgical Anatomy.-The hyoid bone is occasionally fractured, generally from direct vio- 
lence, as in the act of garroting or throttling. It is frequently found broken in those who have 
been hung. The great cornu is the part of the bone most frequently broken, but sometimes 
the fracture takes place through the body of the bone. In consequence of the muscles of the 
1 These ligaments in many animals are distinct bones, and in man are occasionally ossified to a certain extent. THE STERNUM 
155 
tongue having important connections with this bone, there is great pain upon any attempt being 
made to move the tongue, as in speaking or swallowing. 
THE THORAX. 
The thorax, or chest, is an osseo-cartilaginous cage the cavity of which (cavum 
thoracis) contains and protects the principal organs of respiration and circula- 
tion. It is conical in shape, being narrow above and broad below, flattened 
from before backward, and longer behind than in front. It is somewhat 
reniform on transverse section. 
Boundaries.-The posterior surface is formed by the twelve dorsal vertebrae and 
the posterior part of the ribs. It is concave from above downward, and presents 
on each side of the middle line a deep groove, the vertebral groove, in conse- 
quence of the direction backward and outward which the ribs take from their 
vertebral extremities to their angles. The anterior surface is flattened or slightly 
convex, and inclined forward from above downward. It is formed by the sternum 
and costal cartilages. The lateral surfaces are convex; they are formed by the 
ribs, separated from each other by spaces. Each space is called an intercostal 
space (spatium intercostale). These are eleven in number, and are occupied by 
the intercostal muscles. 
The superior or upper opening or aperture of the thorax, the inlet (apertura 
thoracis superior), is reniform in shape, being broader from side to side than 
from before backward. It is formed by the first dorsal vertebra behind, the 
upper margin of the sternum in front, and the first rib on each side. It slopes 
downward and forward, so that the anterior part of the ring is on a lower level 
than the posterior. The antero-posterior diameter is about two inches, and the 
transverse about four. The inferior or lower opening (apertura thoracis inferior) 
is formed by the twelfth dorsal vertebra behind, by the twelfth rib at the sides, 
and in front by the cartilages of the eleventh, tenth, ninth, eighth, and seventh 
ribs, which ascend on either side and form an angle, the subcostal angle (ancjulus 
inf rasternalis), from the apex of which the ensiform cartilage projects. It is 
wider transversely than from before backward. It slopes obliquely downward 
and backward, so that the cavity of the thorax is much deeper behind than in 
front. The Diaphragm closes in the opening forming the floor of the thorax. 
In the female the thorax differs as follows from the male: 1. Its general capa- 
city is less. 2. The sternum is shorter. 3. The upper margin of the sternum 
is on a level with the lower part of the body of the third dorsal vertebra, whereas 
in the male it is on a level with the lower part of the body of the second dorsal 
vertebra. 4. The upper ribs are more movable, and so allow a greater enlarge- 
ment of the upper part of the thorax than in the male. 
The Sternum or Breast Bone 
The sternum (<rr£pvov, the chest), or breast bone (Figs. HO, 111), is a flat, 
narrow bone, situated in the median line of the front of the chest, and con- 
sisting, in the adult, of three portions. It has been likened to an ancient 
sword; the upper piece, representing the handle, is termed the manubrium 
sterni (presternum); the middle and largest piece, which represents the chief 
part of the blade, is termed the gladiolus (mesosternum or corpus sterni); and 
the inferior piece, which is likened to the point of the sword, is termed the 
ensiform or xiphoid process or appendix (processus xiphoideus or metasternum). 
In early youth the sternum is composed of six pieces or stemebrae. In adult life 
the upper piece remains as the manubrium; the inferior piece remains as the 
xiphoid; and the other four pieces fuse together to form the gladiolus. In its 156 
THE SKELETON 
SUBCLAVIUS. 
STERNO-CLEIDOMASTOID.' 
STERNC- 
. HYOID. 
forlst 
Costal 
Cartilage 
Fig. 110.-Sternum and costal cartilages. 
Fig. 111.--Posterior surface of sternum. THE STERNUM 
157 
natural position its inclination is oblique from above downward and forward. It 
is slightly convex in front, concave behind, broad above, becoming narrowed at 
the point where the first and second pieces are connected, after which it again 
widens a little, and is pointed at its extremity. Its average length in the adult is 
about seven inches, being rather longer in the male than in the female. At the 
junction of the manubrium and gladiolus is a distinct angle, the angulus sterni 
(angle of Ludovic or angle of Louis), the manubrium looking forward, the 
gladiolus also looking forward, but to a less degree. This angle is on a level 
with the second rib, and is produced by retraction of the upper portion of the 
thorax. 
First Piece.-The first piece of the sternum, or the manubrium sterni (pre- 
sternum), is of a somewhat triangular form, broad and thick above, narrow 
below at its junction with the middle piece. 
Surfaces.-Its anterior surface, convex from side to side, concave from above 
downward, is smooth, and affords attachment on each side to the Pectoralis 
major and sternal origin of the Sterno-cleido-mastoid muscle. In well-marked 
bones the ridges limiting the attachment of these muscles are very distinct. Its 
posterior surface, concave and smooth, affords attachment on each side to the 
Sterno-hyoid and Sterno-thyroid muscles. 
Borders.-The superior border, the thickest, presents at its centre the pre-sternal 
notch (incisura jugularis), and on each side an oval articular surface, the 
clavicular facet (incisura clavicularis), directed upward, backward, and outward, 
for articulation with the sternal end of the clavicle. The inferior border presents 
an oval, rough surface, covered in the recent state with a thin layer of cartilage, 
for articulation with the second portion of the bone (synchondrosis sternalis). 
The junction of the manubrium with the gladiolus is marked by a transverse 
ridge, which corresponds to the attachment on each side of the cartilage of 
the second rib. The lateral borders are marked above by a depression (incisura 
costalis 1) for the first costal cartilage, and below by a small facet, which, with a 
similar facet on the upper angle of the middle portion of the bone, forms a 
notch (incisura costalis II) for the reception of the costal cartilage of the second 
rib. These articular surfaces are separated by a narrow, curved edge, which 
slopes from above downward and inward. 
Second Piece.-The second piece of the sternum, the corpus sterni or gladiolus 
(mesosternum), considerably longer, narrower, and thinner than the first piece, is 
broader below than above. 
Surfaces.-Its anterior surface (planum sternale) is nearly flat, directed upward 
and forward, and marked by three transverse lines which cross the bone opposite 
the third, fourth, and fifth articular depressions. These lines are produced by the 
union of the four separate pieces of which this part of the bone consists at an early 
period of life. At the junction of the third and fourth pieces is occasionally seen 
an orifice, the sternal foramen; it varies in size and form in different individuals, 
and pierces the bone from before backward. This surface affords attachment 
on each side to the sternal origin of the Pectoralis major. The posterior surface, 
slightly concave, is also marked by three transverse lines, but they are less dis- 
tinct than those in front: this surface affords attachment below, on each side, 
to the Triangularis sterni muscle, and occasionally presents the posterior opening 
of the sternal foramen. 
Borders.-The superior border presents an oval surface for articulation with the 
manubrium. The inferior border is narrow, and articulates with the ensiform 
appendix. Each lateral border presents, at each superior angle, a small facet, 
which, with a similar facet on the manubrium, forms a cavity for the cartilage of 
the second rib; the four succeeding angular depressions receive the cartilages of 
the third, fourth, fifth, and sixth ribs; whilst each inferior angle presents a small 158 
THE SKELETON 
facet, which, with a corresponding one on the ensiform appendix, forms a notch 
for the cartilage of the seventh rib. These articular depressions are known as 
incisura? costales. They are separated by a series of curved interarticular inter- 
vals, which diminish in length from above downward, and correspond to the 
intercostal spaces. Most of the cartilages belonging to the true ribs, as will be 
seen from the foregoing description, articulate with the sternum at the line of 
junction of two of its primitive component segments. This is well seen in many 
of the lower animals, where the separate parts of the bone remain ununited 
longer than in man. In this respect a striking analogy exists between the mode 
of connection of the ribs with the vertebral column and the connection of the 
costal cartilages with the sternum. 
Third Piece.-The third piece of the sternum, the ensiform or xiphoid appendix 
{processus xiphoideus or metasternum), is the smallest of the three; it is thin and 
elongated in form, cartilaginous in structure in youth, but more or less ossified 
at its upper part in the adult. 
Surfaces.-Its anterior surface affords attachment to the chondro-xiphoid 
ligament; its posterior surface, to some of the fibres of the Diaphragm and 
Triangularis sterni muscles; its lateral borders, to the aponeurosis of the abdom- 
inal muscles. Above it articulates with the lower end of the gladiolus, and at each 
superior angle presents a facet (incisura costalis VII), for the lower half of the 
cartilage of the seventh rib; below, by its pointed extremity, it gives attachment 
to the linea alba. This portion of the sternum is very various in appearance, 
being sometimes pointed, broad, and thin, sometimes bifid or perforated by a 
round hole, occasionally curved or deflected considerably to one or the other side. 
Structure.-The bone is composed of delicate cancellous structure, covered by 
a thin layer of compact tissue, which is thickest in the manubrium between the 
articular facets for the clavicles. 
Development.-The cartilaginous sternum originally consists of two bars, situ- 
ated one on either side of the mesial plane and connected with the rib cartilages of 
its own side. These two bars fuse with each other along the middle line, and 
the bone, including the ensiform appendix, is developed by six centres: one for the 
first piece or manubrium, four for the second piece or gladiolus, and one for the 
ensiform appendix. Up to the middle of foetal life the sternum is entirely car- 
for first piece, two or more centres. 
for second piece, usually one. 
Arrest of development 
of lateral pieces, producing 
for third 
for fourth 
for fifth 
2, placed laterally. 
Sternal fissure, and 
.Sternal foramen. 
Fig. 112.-Development of the sternum by six 
centres. Time of appearance. 
Fig. 113.-Time of union of sternum. 
tilaginous, and when ossification takes place the ossific granules are deposited in 
the middle of the intervals between the articular depressions for the costal car- 
tilages, in the following order (Fig. 112): In the first piece, between the fifth and 
sixth months; in the second and third, between the sixth and seventh months; in 
the fourth piece, at the ninth month; in the fifth, within the first year or between 
the first and second years after birth; and in the ensiform appendix, between the THE RIBS 
159 
second and the seventeenth or eighteenth years, by a single centre which makes 
its appearance at the upper part and proceeds gradually downward. To these 
may be added the occasional existence, as described by Breschet, of two small 
episternal centres, which make their appearance one on each side of the pre-sternal 
notch. They are probably vestiges of the episternal bone of the monotremata 
and lizards. It occasionally happens that some of the segments are formed from 
more than one centre, the number and position of which vary (Fig. 114). Thus, 
the first piece may have two, three, or even six centres. When two are present, 
they are generaly situated one above the other, the upper one being the larger;1 
the second piece has seldom more than one; the third, fourth, and fifth pieces 
are often formed from two centres placed laterally, the irregular union of which 
will serve to explain the occasional occurrence of the sternal foramen (Fig. 113), 
1 for 1st piece 
'or manubrium 
5-6th month foetal. 
Rarely unite, 
except in old age. 
2 
3 
4 for 2nd piece 
or gladiolus 
6-7th month. 
4 9th month. 
5 1st year after 
birth. 
Between puberty 
1 and the 25th year. 
Soon after puberty. 
1 for ensiform 
cartilage 
2nd to 18th year 
Partly cartilaginous to 
advanced life. 
Fig. 114.-Peculiarities in number of centres of 
sternum. 
Fig. 115.-Peculiarities in mode of union 
of sternum. 
or of the vertical fissure which occasionally intersects this part of the bone (Fig. 113), 
and which is further explained by the manner in which the cartilaginous matrix, 
in which ossification takes place, is formed. Union of the various centres of the 
gladiolus commences about puberty, from below, and proceeds upward, so that by 
the age of twenty-five they are all united, and this portion of bone consists of one 
piece. The ensiform cartilage becomes joined to the gladiolus about forty. The 
manubrium is occasionally but seldom joined to the gladiolus in advanced life 
by bone. When this union takes place, however, it is generally only superficial, a 
portion of the centre of the sutural cartilage remaining unossified. 
Articulations.-With the clavicles and seven costal cartilages on each side. 
Attachment of Muscles.-To nine pairs and one single muscle: the Pectoralis 
major, Sterno-cleido-mastoid, Sterno-hyoid, Sterno-thyroid, Triangularis sterni, 
aponeuroses of the Obliquus externus, Obliquus internus, Transversalis, Rectus 
muscles, and Diaphragm. 
The Ribs (Costae). 
The ribs are elastic arches of bone, which form the chief part of the thoracic 
walls. They are twelve in number on each side; but this number may be increased 
by the development of a cervical or lumbar rib, or may be diminished to eleven. 
The first seven are connected behind with the spine and in front with the sternum, 
through the intervention of the costal cartilages; they are called true, sternal, or 
vertebro-sternal ribs (costae verce).2 The remaining five are false ribs (costae 
1 Sir George Humphry states that this is "probably the more complete condition." 
2 Sometimes the eighth rib cartilage articulates with the sternum; this condition occurs more frequently on 
the right than on the left side. 160 
THE SKELETON 
spuria:); of these, the first, three have their cartilages attached to the cartilage of 
the rib above, and are called the vertebro-chondral ribs; the last two are free at their 
Angle.. 
'Tuberosity. 
Articular part of tuberosity.' 
Heck. 
•Subcostal groove 
Head.- 
anterior extremities; they are termed floating or 
vertebral ribs. The ribs vary in their direction, 
the upper ones being less oblique than the lower. 
The extent of obliquity reaches its maximum at 
the ninth rib, and gradually decreases from that 
rib to the twelfth. The ribs are situated one be- 
low the other in such a manner that spaces are 
left between them. Each space is called an inter- 
costal space (spatium intercostale}. The length of 
these spaces corresponds to the length of the ribs 
and their cartilages; their breadth is greater in 
front than behind, and between the upper than 
between the lower ribs. The ribs increase in 
length from the first to the seventh, when they 
again diminish to the twelfth. In breadth they 
decrease from above downward; in the upper ten 
the greatest breadth is at the sternal extremity. 
Common Characters of the Ribs. 
A rib from the middle of the series should be 
taken in order to study the common characters of 
the ribs (Figs. 116, 117, and 118). Each rib 
presents two extremities, a posterior or vertebral, 
an anterior or sternal, and an intervening portion 
-the body or shaft. 
Posterior Extremity.-The posterior or ver- 
tebral extremity presents for examination a head, 
neck, and tuberosity. 
The Head (capitulum costce).-The head (Fig. 
118) is marked by a kidney shaped articular 
surface, divided by a horizontal ridge (crista 
capituli) into two facets for articulation with the 
costal cavity formed by the junction of the bodies 
of two contiguous dorsal vertebrae; the upper 
facet is small, the inferior one of larger size; 
the ridge separating them serves for the attach- 
ment of the interarticular ligament. 
The Neck (collum costoc).-The neck is that flattened portion of the rib which 
extends outward from the head; it is about an inch long, and is placed in front 
Body 
or shaft. 
Fig. 116.-A central rib of right side. COMMON CHARACTERS OF THE RIBS 
161 
of the transverse process of the lower of the two vertebrae with which the head 
articulates. Its anterior surface is flat and smooth, its posterior surface is rough 
for the attachment of the middle costo-transverse ligament, and is perforated by 
numerous foramina, the direction of which is less constant than those found on 
the inner surface of the shaft. Of its two borders the 
superior border presents a rough crest (crista colli costa;) 
for the attachment of the anterior costo-transverse liga- 
ment; its inferior border is rounded. On the posterior 
surface of the neck, just where it joins the shaft, and 
nearer the lower than the upper border, is an eminence 
-the tuberosity, or tubercle. 
Tuberosity (tuberculum costoe).- The tuberosity, or 
tubercle, consists of an articular and a non-articular por- 
tion. The articular portion (facies articularis tuberculi 
costoe), the more internal and inferior of the two, pre- 
sents a small, oval surface for articulation with the ex- 
tremity of the transverse process of the lower of the two 
vertebrae to which the head is connected. The non- 
articular portion is a rough elevation, which affords at- 
tachment to the posterior costo-transverse ligament. 
The tubercle is much more prominent in the upper than 
in the lower ribs. 
Anterior Extremity.-The anterior or sternal extremity is flattened, and pre- 
sents a porous, oval, concave depression, into which the costal cartilage is received. 
The Shaft (corpus costoe).-The shaft is thin and flat, so as to present two sur- 
faces, an external and an internal, and two borders, a superior and an inferior. 
Fig. 117.-Ribs and ar- 
ticulations of the vertebrae. 
(Sappey.) 
■Facet for body of upper dorsal vertebra. 
■Ridge for interarticular ligament. 
■Facet for body of lower dorsal vertebra. 
Articular part of tuberosity. 
Non-articular part of tuberosity. 
Fig. 118.-Vertebral extremity of a rib. External surface. 
Surfaces.-The external surface is convex, smooth and marked at its back part, a 
little in front of the tuberosity, by a prominent line, directed obliquely from above 
downward and outward; this gives attachment to a tendon of the Ilio-costalis 
muscle or of one of its accessory portions, and is called the angle (angulus costa?). 
At this point the rib is bent in two directions. If the rib is laid upon its lower 
border, it will be seen that the portion of the shaft in front of the angle rests upon 
this border, while the portion of the shaft behind the angle is bent inward and at 
the same time tilted upward. The interval between the angle and the tuberosity 
increases gradually from the second to the tenth rib. The portion of bone between 
these two parts is rounded, rough, and irregular, and serves for the attachment of 
the Longissimus dorsi muscle. The portion of bone between the tubercle and 
sternal extremity is also slightly twisted upon its own axis, the external surface 
looking downward behind the angle, a little upward in front of it. This surface 
presents, toward its sternal extremity, an oblique line, the anterior angle. The 
internal surface is concave, smooth, directed a little upward behind the angle, a 
little downward in front of it. This surface is marked by a ridge which com- 162 
THE SKELETON 
mences at the lower extremity of the head; it is strongly marked as far as the 
inner side of the angle, and gradually becomes lost at the junction of the anterior 
with the middle third of the bone. The interval between it and the inferior border 
presents a groove, subcostal groove (sulcus costae), for the intercostal vessels and 
nerve. At the back part of the bone this groove belongs to the inferior border, 
but just in front of the angle, where it is deepest and broadest, it corresponds to 
the internal surface. The superior edge of the groove is rounded; it serves for 
the attachment of the Internal intercostal muscle. The inferior edge corresponds 
to the lower margin of the rib and gives attachment to the External intercostal 
muscle. Within the groove are seen the orifices of numerous small foramina 
which traverse the wall of the shaft obliquely from before backward. 
Borders.-The superior border, thick and rounded, is marked by an external 
and an internal lip, more distinct behind than in front; they serve for the attach- 
ment of the External and Internal intercostal muscles. The inferior border, thin 
and sharp, has attached to it the External intercostal muscle. 
Peculiar Ribs. 
The ribs which require especial consideration are five in number-viz., the 
first, second, tenth, eleventh, and twelfth. 
First Rib.-The first rib (Fig. 119) is the shortest and the most curved of 
all the ribs; it is broad and flat, its surface looking upward and downward, and 
its borders inward and outward. The head is of small size, rounded, and presents 
only a single articular facet for articulation with the body of the first dorsal ver- 
tebra. The neck is narrow and rounded. The tuberosity, thick and prominent, 
rests on the outer border. There is no angle, but in this situation the rib is slightly 
bent, with the convexity of the bend upward, so that the head of the bone is 
directed downward. The upper surface of the shaft is marked by two shallow 
depressions, separated by a small rough surface (tuberculum scaleni) for the 
attachment of the Scalenus anticus muscle-the shallow groove in front of it 
transmitting the subclavian vein, the deeper groove behind it (sulcus subclaviee) 
the subclavian artery. Between the groove for the subclavian artery and 
the tuberosity is a rough surface, for the attachment of the Scalenus medius 
muscle. The under surface is smooth, and destitute of the groove observed on the 
other ribs. The outer border is convex, thick, and rounded, and at its posterior 
part gives attachment to the first serration of the Serratus magnus; the inner is 
concave, thin, and sharp, and marked about its centre by the commencement of 
the rough surface for the Scalenus anticus. The anterior extremity is larger and 
thicker than any of the other ribs. 
Second Rib.-The second rib (Fig. 120) is much longer than the first, but bears 
a very considerable resemblance to it in the direction of its curvature. The non- 
articular portion of the tuberosity is occasionally only slightly marked. The angle 
is slight and situated close to the tuberosity, and the shaft is not twisted, so that 
both ends touch any plane surface upon which it may be laid; but there is a similar 
though slighter bend, with its convexity upward, to that found in the first rib. The 
shaft is not horizontal, like that of the first rib, its outer surface, which is convex, 
looking upward and a little outward. It presents, near the middle, a rough emi- 
nence, tuberositas costae II, for the attachment of the second and third digitations 
of the Serratus magnus; behind and above which is attached the Scalenus 
posticus. The inner surface, smooth and concave, is directed downward and a 
little inward; it presents a short groove toward its posterior part. 
Tenth Rib.-The tenth rib (Fig. 121) has only a single articular facet on its head. 
Eleventh and Twelfth Ribs.-The eleventh and twelfth ribs (Figs. 122 and 
123) have each a single articular facet on the head, which is of rather large size; PECULIAR RIBS 
163 
they have no neck or tuberosity, and are pointed at the extremity. The eleventh 
has a slight angle and a shallow groove on the lower border. The twelfth has 
neither, and is much shorter than the eleventh, and the head has a slight inclina- 
tion downward. Sometimes the twelfth rib is even shorter than the first. 
Shortest 
Surfaces horizontal- 
Fig. 119. 
Angle 
slightly marked 
and close to 
tuberosity. 
First serration 
of Serratus magnus. 
Fig. 120. 
Second 
Serration 
Fig.121. 
Single articular facet- 
Fig. 122. 
Single articular facet. 
no 
Tuberosity 
Fig. 123. 
Single articular facet. 
Figs. 119-123.-Peculiar ribs. 
Structure.-The ribs consist of cancellous tissue enclosed in a thin, compact 
layer. 
Development.-Each rib, with the exception of the last two, is developed by 
three centres: one for the shaft, one for the head, and one for the tubercle. The 
last two have only two centres, that for the tubercle being wanting. Ossification 
commences in the shaft of the ribs at a very early period, before its appearance in 
the vertebrae. The epiphysis of the head, which is of slightly angular shape, and 
that for the tubercle, of a lenticular form, make their appearance between the six- 
teenth and twentieth years, and are not united to the rest of the bone until about 
the twenty-fifth year. 164 
THE SKELETON 
Attachment of Muscles.-To nineteen: The Internal and External intercostals, 
Scalenus anticus, Scalenus medius, Scalenus posticus, Pectoralis minor, Serratus 
magnus, Obliquus externus, Quadratus lumborum, Diaphragm, Latissimus dorsi, 
Serratus posticus superior, Serratus posticus inferior, Ilio-costalis, Musculus acces- 
sorius ad ilio-costalem, Longissimus dorsi, Cervicalis ascendens, Levatores costa- 
rum, and Infracostales. 
The Costal Cartilages. 
The costal cartilage (cartilago costalis) (Fig. 110) is white, hyaline cartilage. The 
cartilages serve to prolong the ribs forward to the front of the chest, and they 
contribute very materially to the elasticity of its walls. The first seven are con- 
nected with the sternum, the next three with the lower border of the cartilage of 
the preceding rib. The cartilages of the last two ribs have pointed extremities, 
which terminate in free ends in the walls of the abdomen. Like the ribs, the 
costal cartilages vary in their length, breadth, and direction. They increase in 
length from the first to the seventh, then gradually diminish to the last. They 
diminish in breadth, as well as the intervals between them, from the first to the 
last. They are broad at their attachment to the ribs, and taper toward their sternal 
extremities, excepting the first two, which are of the same breadth throughout, 
and the sixth, seventh, and eighth, which are enlarged where their margins are 
in contact. In direction they also vary: the first descends a little, the second is 
horizontal, the third ascends slightly, while all the rest follow the course of the 
ribs for a short extent, and then ascend to the sternum or preceding cartilage. 
Each costal cartilage presents two surfaces, two borders, and two extremities. 
Surfaces.-The anterior surface is convex, and looks forward and upward: that 
of the first gives attachment to the costo-clavicular ligament and the Subclavius 
muscle; that of the second, third, fourth, fifth, and sixth, at their sternal ends, 
to the Pectoralis major.1 The others are covered by, and give partial attachment 
to, some of the great flat muscles of the abdomen. The posterior surface is con- 
cave, and directed backward and downward, the first giving attachment to the 
S ter no-thyroid, the third to the sixth inclusive to the Triangularis sterni, and 
the six or seven inferior ones to the Transversalis muscle and the Diaphragm. 
Borders.-Of the two borders, the superior border is concave, the inferior con- 
vex; they afford attachment to the internal Intercostal muscles, the upper border 
of the sixth giving attachment to the Pectoralis major muscle. The contiguous 
borders of the sixth, seventh, and eighth, and sometimes the ninth and tenth, 
costal cartilages present small, smooth, oblong-shaped facets at the points where 
they articulate. 
Extremities.-Of the two extremities, the outer extremity is continuous with the 
osseous tissue of the rib to which it belongs. The inner extremity of the first is 
continuous with the sternum; the six succeeding ones have rounded extremities, 
which are received into shallow concavities on the lateral margins of the sternum. 
The inner extremities of the eighth, ninth, and tenth costal cartilages are pointed, 
and are connected with the cartilage above. Those of the eleventh and twelfth 
are free and pointed. 
The costal cartilages are most elastic in youth, those of the false ribs being 
more so than the true. In old age they become of a deep yellow color, and are 
prone to calcify. 
Attachment of Muscles.-To nine: the Subclavius, Sterno-thyroid, Pectoralis 
major, Internal oblique, Transversalis, Rectus, Diaphragm, Triangularis sterni, 
and Internal intercostals. 
1 The first and seventh also, occasionally, give origin to the same muscle. THE COSTAL CARTILAGES 
165 
Surface Form.-The bones of the chest are to a very considerable extent covered by mus- 
cles, so that in the strongly developed muscular subject they are for the most part concealed. 
In the emaciated subject, on the other hand, the ribs, especially in the lower and lateral region, 
stand out as prominent ridges with the sunken, intercostal spaces between them. 
In the middle line, in front, the superficial surface of the sternum is to be felt throughout 
its entire length, at the bottom of a deep median furrow situated between the two great pectoral 
muscles and called the sternal furrow. These muscles overlap the anterior surface somewhat, so 
that the whole of the sternum in its entire width is not subcutaneous; and this overlapping is 
greater opposite the centre of the bone than above and below, so that the furrow is wider at its 
upper and lower parts, but narrower in the middle. The centre of the upper border of the ster- 
num is visible, constituting the pre-sternal notch, but the lateral parts of this border are obscured 
by the tendinous origins of the Sterno-mastoid muscles, which present themselves as oblique 
tendinous cords, which narrow and deepen the notch. Lower down on the subcutaneous surface 
a well-defined transverse ridge, the angle of Ludovic, is always to be felt. This denotes the line 
of junction of the manubrium and body of the bone, and is a useful guide to the second costal 
cartilage, and thus to the identity of any given rib. The second rib being found through its 
costal cartilage, it is easy to count downward and find any other. From the middle of the 
sternum the furrow spreads out, and, exposing more of the surface of the body of the bone, 
terminates below in a sudden depression, the infrasternal depression or pit of the stomach 
(scrobiculus cordis}, which corresponds to the ensiform cartilage. This depression lies between 
the cartilages of the seventh ribs, and in it the ensiform cartilage may be felt. The sternum in 
its vertical diameter presents a general convexity forward, the most prominent point of which 
is at the joint between the manubrium and gladiolus. 
On each side of the sternum the costal cartilages and ribs on the front of the chest are par- 
tially obscured by the great pectoral muscles; through which, however, they are to be felt as 
ridges, with yielding intervals between them, corresponding to the intercostal spaces. Of these 
spaces, the one between the second and third ribs is the widest, the next two somewhat nar- 
rower, and the remainder, with the exception of the last two, comparatively narrow. 
The lower border of the Pectoralis major muscle corresponds to the fifth rib, and below 
this, on the front of the chest, the broad, flat outline of the ribs, as they begin to ascend, and 
the more rounded outline of the costal cartilages, are often visible. The lower boundary of 
the front of the thorax, the abdomino-thoracic arch, which is most plainly seen by arching the 
body backward, is formed by the ensiform cartilage and the cartilages of the seventh, eighth, 
ninth, and tenth ribs, and the extremities of the eleventh and twelfth ribs or their cartilages. 
On each side of the chest, from the axilla downward, the flattened external surfaces of the 
ribs may be defined in the form of oblique ridges, separated by depressions corresponding to the 
intercostal spaces. They are, however, covered by muscles, which obscure their outline to a 
certain extent in the strongly developed. Nevertheless, the ribs, with the exception of the first, 
can generally be followed over the front and sides of the chest without difficulty. The first rib, 
being almost completely covered by the clavicle and scapula, can only be distinguished in a 
small portion of its extent. At the back the angles of the ribs form a slightly-marked oblique 
line on each side of and some distance from the vertebral spines. This line diverges some- 
what as it descends, and external to it is a broad, convex surface caused by the projection of 
the ribs beyond their angles. Over this surface, except where covered by the scapula, the 
individual ribs can be distinguished. 
Surgical Anatomy.-Malformations of the sternum present nothing of surgical importance 
beyond the fact that abscesses of the mediastinum may sometimes escape through the sternal 
foramen. Fractures of the sternum are by no means common, owing, no doubt, to the elasticity 
of the ribs and their cartilages, which support it like so many springs. When broken it is fre- 
quently associated with fracture of the spine, and may be caused by forcibly bending the body 
either backward or forward until the chin becomes impacted against the top of the sternum. It 
may also be fractured by direct violence or by muscular action. The fracture usually occurs in 
the upper half of the body of the bone. Dislocation of the gladiolus from the manubrium also 
takes place, and is sometimes described as a fracture. 
The bone, cancellous in structure and being subcutaneous, is frequently the seat of gummatous 
tumors, and not uncommonly is affected with caries. Occasionally the bone, and especially 
its ensiform appendix, becomes altered in shape and driven inward by the pressure, in work- 
men, of tools against the chest. 
The ribs are frequently broken, though from their connections and shape they are able to 
withstand great force, yielding under the injury and recovering themselves like a spring. The 
middle of the series are the ones most liable to fracture. The first, and to a less extent the 
second, being protected by the clavicle, are rarely fractured; and the eleventh and twelfth, on 
account of their loose and floating condition, enjoy a like immunity. The fracture generally 
occurs from indirect violence, from forcible compression of the chest-wall, and the bone then 
gives way at its weakest part-i. e., just in front of the angle. But the ribs may also be broken 
by direct violence, when the bone gives away and is driven inward at the point struck, or they 166 
THE SKELETON 
may be broken by muscular action. It seems probable, however, that in the latter case the 
bone has undergone some atrophic changes. Fracture of the ribs is frequently complicated with 
some injury to the viscera contained within the thorax or upper part of the abdominal cavity, 
and this is most likely to occur in fractures from direct violence. 
Fracture of the costal cartilages may also take place, though it is a comparatively rare injury. 
The thorax is frequently found to be altered in shape in certain diseases. 
The shape of the rickety thorax is produced chiefly by atmospheric pressure. The balance 
between the air on the inside of the chest and the outside during some stage of respiration is not 
equal, the preponderance being in favor of the air outside; and this, acting on the softened ribs, 
causes them to be forced in at the junction of the cartilages with the bones, which is the weakest 
part. In consequence of this the sternum projects forward, with a deep depression on either side 
caused by the sinking in of the softened ribs. The depression is less on the left side, on account 
of the ribs being supported by the heart. The condition is known as pigeon-breast. The 
lower ribs, however, are not involved in this deformity, as they are prevented from falling in by 
the presence of the stomach, liver, and spleen. And when the liver and spleen are enlarged, 
as they sometimes are in rickets, the lower ribs may be pushed outward: this causes a trans- 
verse constriction just above the costal arch. The anterior extremities of the ribs are usually 
enlarged in rickets, giving rise to what has been termed the rickety rosary. The phthisical 
chest is often long and narrow, flattened from before backward, and with great obliquity of the 
ribs and projection of the scapulae. In pulmonary emphysema the chest is enlarged in all its 
diameters, and presents on section an almost circular outline. It has received the name of the 
barrel-shaped chest. In severe cases of lateral curvature of the spine the thorax becomes 
much distorted. In consequence of the rotation of the bodies of the vertebrm which takes 
place in this disease the ribs opposite the convexity of the dorsal curve become extremely con- 
vex behind, being thrown out and bulging, and at the same time flattened in front, so that the 
two ends of the same rib are almost parallel. Coincident with this, the ribs on the opposite 
side, on the concavity of the curve, are sunk and depressed behind and bulging and convex in 
front. In addition to this the ribs become occasionally welded together by bony material. 
The ribs are frequently the seat of caries leading to abscesses and sinuses, which may 
burrow to a considerable extent over the wall of the chest. The only special anatomical point 
in connection with abscesses and sinuses is that care must be taken in dealing with them that 
the intercostal space is not punctured and the pleural cavity opened or the intercostal vessels 
wounded, as the necrosed portion of bone is generally situated on the internal surface of the rib. 
In cases of empyema the chest requires opening to evacuate the pus. There is consider- 
able difference of opinion as to the best position to do this. Probably the best place for inter- 
costal drainage is between the fifth and sixth ribs, in or a little in front of the mid-axillary line. 
This is the last part of the cavity to be closed by the expansion of the lung; it is not thickly 
covered by soft parts; the space between the two ribs is sufficiently great to allow of the intro- 
duction of a fair-sized drainage-tube, and when the patient is confined to bed he does not He 
upon the drainage-tube as he does when the opening is posterior. Better than intercostal drain- 
age in the vast majority of cases is rib resection and drainage. A portion of the fifth or sixth 
rib should be removed in the mid-axillary line. In chronic empyema the lung becomes shrunken 
and adherent and simple drainage will not bring about a cure. It is necessary in such cases 
to do an operation that will permit of collapse of the chest wall. Estlander's operation consists 
in resecting a portion of every rib which overlies the cavity of the empyema. Schede's opera- 
tion consists in removing ribs from the second rib down over the empyema cavity- The ribs 
are removed from cartilages to angles, and intercostal muscles and the parietal layer of the 
pleura are also taken away. Fowler and de Lorme not only practice extensive rib resection 
and remove the parietal layer of the pleura, but also remove the pulmonary pleura (total pleu- 
rectomy or pulmonary decortication). 
THE EXTREMITIES. 
The extremities, or limbs, are those long, jointed appendages of the bodv 
which are connected with the trunk by one end and free in the rest of their extent. 
They are four in number: an upper or thoracic pair, connected with the thorax 
through the intervention of the shoulder, and subservient mainly to prehension; 
and a lower pair, connected with the pelvis, intended for support and locomotion. 
Both pairs of limbs are constructed after one common type, so that they present 
numerous analogies, while at the same time certain differences are observed 
between the upper and lower pair, dependent on the peculiar offices they have 
to perform. THE CLAVICLE 
167 
The bones by which the upper and lower limbs are attached to the trunk are 
named respectively the shoulder and pelvic girdles, and they are constructed on the 
same general type, though presenting certain modifications relating to the different 
uses to which the upper and lower limbs are respectively applied. The shoulder 
girdle is formed by the scapulae and clavicles, and is imperfect in front and behind. 
In front, however, the girdle is completed by the upper end of the sternum, with 
which the inner extremities of the clavicle articulate. Behind, the girdle is widely 
imperfect and the scapula is connected to the trunk by muscles only. The pelvic 
girdle is formed by the innominate bones, and is completed in front through the 
symphysis pubis, at which the two innominate bones articulate with each other. 
It is imperfect behind, but the intervening gap is filled in by the upper part of 
the sacrum. The pelvic girdle, therefore, presents, with the sacrum, a complete 
ring, comparatively fixed, and presenting an arched form which confers upon it a 
solidity manifestly intended for the support of the trunk, and in marked contrast 
to the lightness and mobility of the shoulder girdle. 
With regard to the morphology of these girdles, the blade of the scapula is 
generally believed to correspond to the ilium; but with regard to the clavicles 
there is some difference of opinion: formerly it was believed that they corre- 
sponded to the ossa pubis, meeting at the symphysis, but it is now generally 
taught that the clavicle has no homologue in the pelvic girdle, and that the os 
pubis and ischium are represented by the small coracoid process in man and 
most mammals. 
THE UPPER EXTREMITY 
The bones of the upper extremity consist of those of the shoulder girdle, of the 
arm, the forearm, and the hand. 
The shoulder girdle consists of the clavicle and the scapula. 
THE SHOULDER GIRDLE. 
The Clavicle or Collar Bone (Clavicula). 
The clavicle or key bone (clavis, a key) obtains it name from its supposed 
resemblance to the key used by the Romans. It forms the anterior portion of the 
shoulder girdle. It is a long bone, curved somewhat like the italic letter /, and 
placed nearly horizontally at the upper and anterior part of the thorax, imme- 
diately above the first rib. It articulates by its inner extremity with the upper 
border of the sternum, and by its outer extremity with the acromion process of the 
scapula, serving to sustain the upper extremity in the various positions which it 
assumes, whilst at the same time it allows of great latitude of motion in the arm.1 
It presents a double curvature when looked at in front, the convexity being for- 
ward at the sternal end and the concavity at the scapular end. Its outer third is 
flattened from above downward, and extends, in the natural position of the bone, 
from a point opposite the coracoid process to the acromion. Its inner two-thirds 
are of a prismatic form, and extend from the sternum to a point opposite the cora- 
coid process of the scapula. 
Outer, External, or Flattened Portion.-The outer third is flattened from above 
downward, so as to present two surfaces, an upper and a lower; and two borders, 
an anterior and a posterior. 
1 The clavicle acts especially as a fulcrum to enable the muscles to give lateral motion to the arm. It is 
accordingly absent in those animals whose fore limbs are used only for progression, but is present for the most 
part in those animals whose anterior extremities are clawed and used for prehension, though in some of them- 
as, for instance, in a large number of the carnivora-it is merely a rudimentary bone suspended among the 
muscles, and not articulating with the scapula or sternum. 168 
THE SKELETON 
Surfaces.-The upper surface is flattened, rough, marked by impressions for the 
attachment of the Deltoid in front and the Trapezius behind; between these two 
impressions, externally, a small portion of the bone is subcutaneous. The under 
surface is flattened. At its posterior border, a little external to the point where the 
prismatic joins with the flattened portion, is a rough eminence, the conoid tuber.de 
(tuberositas coracoidea); this, in the natural position of the bone, surmounts the 
coracoid process of the scapula and gives attachments to the conoid ligament. 
From this tubercle an oblique line, occasionally a depression, passes forward 
and outward to near the outer end of the anterior border; it is called the oblique 
line or trapezoid ridge, and affords attachment to the trapezoid ligament. 
Borders.-The anterior border is concave, thin, and rough, and gives attachment 
to the Deltoid; it occasionally presents, at its inner end, at the commencement of 
the deltoid impression, a tubercle, the deltoid tubercle, which is sometimes to be 
felt in the living subject. The posterior border is convex, rough, broader than the 
anterior, and gives attachment to the Trapezius. 
Inner, Internal, or Prismatic Portion.-The prismatic portion forms the inner 
two-thirds of the bone. It is curved so as to be convex in front, concave behind, 
and is marked by three borders, separating three surfaces. 
Borders.-The anterior border is continuous with the anterior margin of the flat 
portion. At its commencement it is smooth, and corresponds to the interval 
between the attachment of the Pectoralis major and Deltoid muscles; at the inner 
half of the clavicle it forms the lower boundary of an elliptical space for the 
attachment of the clavicular portion of the Pectoralis major, and approaches the 
posterior border of the bone. The superior border is continuous with the posterior 
margin of the flat portion, and separates the anterior from the posterior surface. 
At its commencement it is smooth and rounded, becomes rough toward the inner 
third for the attachment of the Sterno-mastoid muscle, and terminates at the 
upper angle of the sternal extremity. The posterior or subclavian border separates 
the posterior from the inferior surface, and extends from the conoid tubercle to 
the rhomboid impression. It forms the posterior boundary of the groove for the 
Subclavius muscle, and gives attachment to a layer of cervical fascia covering 
the Omo-hyoid muscle. 
Surfaces.-The anterior surface is included between the superior and anterior 
borders. It is directed forward and a little upward at the sternal end, outward 
and still more upward at the acromial extremity, where it becomes continuous 
with the upper surface of the flat portion. Externally, it is smooth, convex, 
nearly subcutaneous, being covered only by the Platysma; but, corresponding 
to the inner half of the bone, it is divided by a more or less prominent line into 
two parts: a lower portion, elliptical in form, rough, and slightly convex, for the 
attachment of the Pectoralis major; and an upper part, which is rough, for the 
attachment of the Sterno-cleido-mastoid. Between the two muscular impressions 
is a small subcutaneous interval. The posterior or cervical surface is smooth, 
flat, and looks backward toward the root of the neck. It is limited, above, by the 
superior border; below, by the subclavian border; internally, by the margin of the 
sternal extremity; externally, it is continuous with the posterior border of the flat 
portion. It is concave from within outward, and is in relation, by its lower part, 
with the suprascapular vessels. This surface, at about the junction of the inner 
and outer curves, is also in close relation with the brachial plexus and subclavian 
vessels. It gives attachment, near the sternal extremity, to part of the Sterno-hyoid 
muscle; and presents, at or near the middle, a foramen, nutrient foramen (foramen 
nutricium). It opens into a canal, nutrient canal (canalis nutricius), which is 
directed obliquely outward and transmits the chief nutrient artery of the bone. 
Sometimes there are two foramina on the posterior surface, or one on the 
posterior, and one on the inferior surface. The inferior or subclavian surface THE CLAVICLE 
169 
is bounded, in front, by the anterior border; behind, by the subclavian border. 
It is narrow internally, but gradually increases in width externally, and is 
continuous with the under surface of the flat portion. Commencing at the 
sternal extremity may be seen a small facet, the costal facet, for articulation 
with the cartilage of the first rib. This is continuous with the articular surface 
Acromial extremity. 
Sternal extremity. 
Fig. 124.-Left clavicle. Superior surface. 
at the sternal end of the bone. External to this is a broad, rough surface, the 
rhomboid impression (tuberositas costalis), rather more than an inch in length, for 
the attachment of the costo-clavicular (rhomboid) ligament. The remaining part 
of this surface is occupied by a longitudinal groove, the subclavian groove, broad 
and smooth externally, narrow and more uneven internally; it gives attachment to 
the Subclavius muscle, and by its margins to the costo-coracoid membrane, 
which splits to enclose the muscle. Not infrequently this groove is subdivided 
into two parts by a longitudinal line, which gives attachment to the intermuscular 
septum of the Subclavius muscle. 
o' 
2 
Fig. 125.-Left clavicle. Inferior surface. 
Internal or Sternal Extremity (extremitas sternalis).-The internal or sternal 
extremity of the clavicle is triangular in form, directed inward and a little down- 
ward and forward; and presents an articular facet (jacies articularis sternalis), 
concave from before backward, convex from above downward, which articulates 
with the sternum through the intervention of an interarticular fibro-cartilage; 
the circumference of the articular surface is rough, for the attachment of 
numerous ligaments. The posterior border of this surface is prolonged back- 
ward, so as to increase the size of the articular facet; the upper border gives 
attachment to the interarticular fibro-cartilage, and the lower border is con- 
tinuous with the costal facet on the inner end of the inferior or subclavian sur- 
face, which articulates with the cartilage of the first rib. 
Outer or Acromial Extremity (extremitas acromialis).-The outer or acromial 
extremity, directed outward and forward, presents a small, flattened, oval facet, 170 
THE SKELETON 
acromial surface (facies articularis acromialis), which looks obliquely downward, 
for articulation with the acromion process of the scapula. The circumference 
of the articular facet is rough, especially above, for the attachment of the 
acromio-cla vicular ligaments. 
Peculiarities of the Bone in the Sexes and in Individuals.-In the female the 
clavicle is generally shorter, thinner, less curved, and smoother than in the male. 
In those persons who perform considerable manual labor, which brings into con- 
stant action the muscles connected with this bone, it becomes thicker and more 
curved, its ridges for muscular attachment become prominently marked. The 
right clavicle is generally longer, thicker, and rougher than the left. 
Structure.-The shaft, as well as the extremities, consists of cancellous tissue, 
invested in a compact layer much thicker in the middle than at either end. The 
clavicle is highly elastic, by reason of its curves. From the experiments of Mr. 
Ward it has been shown that it possesses sufficient longitudinal elastic force to 
project its own weight nearly two feet on a level surface when a smart blow is 
struck on it; and sufficient transverse elastic force, opposite the centre of its 
anterior convexity, to throw its own weight about a foot. This extent of elastic 
power must serve to moderate very considerably the effect of concussions received 
upon the point of the shoulder. 
Development.-By two centres: one for the shaft and outer extremity and 
one for the sternal extremity. The centre for the shaft appears very early, 
before any other bone-according to Beclard, as early as the thirtieth day. 
The centre for the sternal end makes its appearance about the eighteenth or 
twentieth year, and unites with the rest of the bone about the twenty-fifth year. 
Articulations.-With the sternum, scapula, and cartilage of the first rib. 
Attachment of Muscles.-To six : the Sterno-cleido-mastoid, Trapezius, 
Pectoralis major, Deltoid, Subclavius, and Sterno-hyoid. 
Surface Form.-The clavicle can be felt throughout its entire length, even in persons who 
are very fat. Commencing at the inner end, the enlarged sternal extremity, where the bone 
projects above the upper margin of the sternum, can be felt, forming with the sternum and the 
rounded tendon of the Sterno-mastoid a V-shaped notch, the pre-sternal notch. Passing out- 
ward, the shaft of the bone can be felt immediately under the skin, with its convexity forward 
in the inner two-thirds, the surface partially obscured above and below by the attachments of 
the Sterno-mastoid and Pectoralis major muscles. In the outer third it forms a gentle curve 
backward, and terminates at the outer end in a somewhat enlarged extremity which articulates 
with the acromial process of the scapula. The direction of the clavicle is almost, if not quite, 
horizontal when the arm is lying quietly by the side, though in well-developed subjects it may 
incline a little upward at its outer end. Its direction is, however, very changeable, altering 
with the varying movements of the shoulder-joint. 
Surgical Anatomy.-The clavicle is the most frequently fractured of any single bone in the 
body. This is due to the fact that it is much exposed to violence, and is the only bony connec- 
tion between the upper limb and the trunk. The bone, moreover, is slender, and is very super- 
ficial. The bone may be broken by direct or indirect violence or by muscular action. The most 
common cause is, however, from indirect violence, and the bone then gives way at the junction 
of the fixed outer one-third with the movable inner two-thirds of the bone. This is the weakest 
anil most slender part of the bone. The fracture is generally oblique, and the displacement 
of the outer fragments is inward, away from the surface of the body; hence compound 
fracture of the clavicle is of rare occurrence. The inner fragment as a rule is little displaced 
(page 503). Beneath the bone the main vessels of the upper limb and the great nerve-cords of 
the brachial plexus lie on the first rib, and are liable to be wounded in fracture, especially in 
fracture from direct violence, when the force of the blow drives the broken ends inward. For- 
tunately, the Subclavius muscle is interposed between these structures and the clavicle, and 
this often protects them from injury. ' 
The clavicle is not uncommonly the seat of sarcomatous tumors, rendering the operation 
of excision of the entire bone necessary. This operation is best performed by exposing the 
bone freely, disarticulating at the acromial end, and turning it inward. The removal of 
the outer part is comparatively easy, but resection of the inner part is fraught with difficulty, the 
main danger being the risk of wounding the great veins which are in relation with its under 
surface. THE SCAPULA 
171 
The Scapula or Shoulder Blade. 
The scapula (axarAvr^ a spade), or blade bone, forms the back part of 
the shoulder girdle. It is a large, flat bone, triangular in shape, situated at 
the posterior aspect and side of the thorax, between the second and seventh, or 
sometimes the eighth, ribs, its internal border or base being about an inch from 
and nearly but not quite parallel with the spinous processes of the vertebrae, so 
that it is rather closer to them above than below. It presents for examination 
two surfaces, three borders, and three angles. 
Fig. 126.-Left scapula. Anterior surface or venter. 
Surfaces. Anterior or Costal Surface, Ventral Aspect or Venter (facies costalis).- 
The anterior surface (Fig. 126) presents a broad concavity, the subscapular 
fossa (fossa subscapularis). It is marked, in the inner two-thirds, by several 
oblique ridges (Unece musculares), which pass from behind outward and upward; 
the outer third is smooth. The oblique ridges give attachment to the tendinous 
intersections, and the surfaces between them to the fleshv fibres, of the Sub- 172 
THE SKELETON 
scapularis muscle. The anterior third of the fossa, which is smooth, is covered 
by, but does not afford attachment to, the fibres of this muscle. The venter is 
separated from the internal border by a smooth, triangular margin at the supe- 
rior and inferior angles, and in the interval between these by a narrow edge which 
is often deficient. This marginal surface affords attachment throughout its entire 
extent to the Serratus magnus muscle. The subscapular fossa presents a trans- 
verse depression at its upper part, where the bone appears to be bent on itself, 
forming a considerable angle, called the subscapular angle (angulus subscapular is), 
thus giving greater strength to the body of the bone from its arched form, whilst 
the summit of the arch serves to support the spine and acromion process. It is in 
this situation that the fossa is deepest, so that the thickest part of the Subscapu- 
laris muscle lies in a line perpendicular to the plane of the glenoid cavity, and 
must consequently operate most effectively on the head of the humerus, which 
is contained in that cavity. The portion of bone between the suprascapular 
notch and the infraglenoid tubercle is sometimes called the surgical neck. 
Posterior or Dorsal Surface or Dorsum (facies dorsalis).-The posterior or dorsal 
surface (Fig. 127) is arched from above downward, alternately concave and 
convex from side to side. It is subdivided unequally into two parts by the 
spine; the portion above the spine is called the supraspinous fossa, and that below 
it the infraspinous fossa. 
The supraspinous fossa (fossa supraspinata), the smaller of the two, is concave, 
smooth, and broader at the vertebral than at the humeral extremity. It affords 
attachment by its inner two-thirds to the Supraspinatus muscle. 
The infraspinous fossa (fossa infraspinata) is much larger than the preceding; 
toward its vertebral margin a shallow concavity is seen at its upper part; its centre 
presents a prominent convexity, whilst toward the axillary border is a deep groove 
which runs from the upper toward the lower part. The inner two-thirds of this 
surface affords attachment to the Infraspinatus muscle; the outer third is only cov- 
ered by it, without giving origin to its fibres. This surface is separated from the 
axillary border by an elevated ridge, which runs from the lower marginof the glenoid 
cavity downward and backward to the posterior border, about an inch above the in- 
ferior angle. The ridge serves for the attachment of a strong aponeurosis which 
separates the Infraspinatus from the two Teres muscles. The surface of bone between 
this line and the axillary border is narrow in the upper two-thirds of its extent, 
and traversed near its centre by a groove for the passage of the dorsalis scapula* 
vessels; it affords attachment to the Teres minor muscle. Its lower third presents a 
broader, somewhat triangular surface, which gives origin to the Teres major, and 
over which the Latissimus dorsi glides; sometimes the latter muscle takes origin 
by a few fibres from this part. The broad and narrow portions of bone above 
alluded to are separated by an oblique line which runs from the axillary border, 
downward and backward, to meet the elevated ridge: to it is attached the 
aponeurosis separating the two Teres muscles from each other. 
The spine (spina scapulae) is a prominent plate of bone which crosses obliquely 
the inner four-fifths of the dorsum of the scapula at its upper part, and separates the 
supra-from the infraspinous fossa: it commences at the vertebral border by a smooth, 
triangular surface, over which the Trapezius glides, separated from the bone by a 
bursa, and, gradually becoming more elevated as it passes outward, terminates in 
the acromion process, which overhangs the shoulder-joint. The spine is triangular 
and flattened from above downward, its apex corresponding to the vertebral 
border, its base (which is directed outward) to the neck of the scapula. It pre- 
sents two surfaces and three borders. Its superior surface is concave, assists 
in forming the supraspinous fossa, and affords attachment to part of the Supra- 
spinatus muscle. Its inferior surface forms part of the infraspinous fossa, gives 
origin to part of the Infraspinatus muscle, and presents near its centre the orifice THE SCAPULA 
173 
of a nutrient canal. Of the three borders, the anterior is attached to the dorsum 
of the bone; the posterior, or crest of the spine, is broad, and presents two lips 
and an intervening rough interval. To the superior lip is attached the Trapezius 
to the extent shown in the figure. A rough tubercle is generally seen occupying 
that portion of the spine which receives the insertion of the middle and inferior 
fibres of this muscle. To the inferior lip, throughout its whole length, is attached 
Groove for Dorsalis 
Scapulx Artery. 
Fig. 127. Left scapula. Posterior surface or dorsum. 
the Deltoid. The intervals between the lips is also partly eovered by the tendinous 
fibres of these muscles. 'The external border, or base, the shortest of the three, is 
slightly concave, its edge thick and round, continuous above with the under sur- 
face of the acromion process, below with the neck of the scapula. The narrow 
portion of bone external to this border, and separating it from the glenoid cavity, 
is called the great scapular notch, and serves to connect the supra- and infraspinous 
fossae. 174 
THE SKELETON 
The acromion process (acromion), so called from forming the summit of the 
shoulder (axpov, a summit; a>po^, the shoulder), is a large and somewhat triangular 
or oblong process, flattened from behind forward, directed at first a little outward, 
and then curving forward and upward, so as to overhang the glenoid cavity. Its 
upper surface, directed upward, backward, and outward, is convex, rough, and 
gives attachment to some fibres of the Deltoid, and in the rest of its extent it is 
subcutaneous. Its under surface is smooth and concave. Its outer border is thick 
and irregular, and presents three or four tubercles for the tendinous origins of the 
I )eltoid muscle. Its inner margin, shorter than the outer, is concave, gives attach- 
ment to a portion of the Trapezius muscle, and presents about its centre a small 
oval surface for articulation with the acromial end of the clavicle. Its apex, which 
corresponds to the point of meeting of these two borders in front, is thin, and 
has attached to it the coraco-acromial ligament. 
Margins or Borders of the Scapula. Superior Border (margo superior).-Of the 
three borders of the scapula, the superior is the shortest and thinnest; it is concave 
and extends from the superior angle to the coracoid process. At its outer part is a 
deep, semicircular notch, the suprascapular notch (incisura scapula;), formed partly 
by the base of the coracoid process. This notch is converted into a foramen by the 
transverse ligament, and serves for the passage of the suprascapular nerve. Some- 
times this foramen is entirely surrounded by bone. The adjacent margin of the 
superior border affords attachment to the Omo-hyoid muscle. 
External or Axillary Border (margo axillaris).-The external or axillary border 
is the thickest of the three. It commences above at the lower margin of the 
glenoid cavity, and inclines obliquely downward and backward to the inferior 
angle. Immediately below the glenoid cavity is a rough impression, the infra- 
glenoid tubercle (tuberositas infraglenoidalis), about an inch in length, which 
affords attachment to the long head of the Triceps muscle; in front of this is 
a longitudinal groove, which extends as far as the lower third of the axillary 
border and affords origin to part of the Subscapularis muscle. The inferior 
third of this border, which is thin and sharp, serves for the attachment of a few 
fibres of the Teres major behind and the Subscapularis in front. 
Internal or Vertebral Border (margo vertebralis).-The internal or vertebral bor- 
der, also named the base, is the longest of the three, and extends from the superior to 
the inferior angle of the bone. It is arched, is intermediate in thickness between the 
superior and the external borders, and the portion of it above the spine is bent con- 
siderably outward, so as to form an obtuse angle with the lower part. The vertebral 
border presents an anterior lip, a posterior lip, and an intermediate space. The ante- 
rior lip affords attachment to the Serratus magnus; the posterior lip, to the Supra- 
spinatus above the spine, the Infraspinatus below; the interval between the two lips, 
to the Levator anguli scapulae above the triangular surface at the commencement 
of the spine, the Rhomboideus minor to the edge of that surface; the Rhomboideus 
major being attached by means of a fibrous arch connected above to the lower 
part of the triangular surface at the base of the spine, and below to the lower part 
of the posterior border. 
Angles. Superior or Mesial Angle (angulus medialis).-Of the three angles, the 
superior, formed by the junction of the superior and internal borders, is thin, 
smooth, rounded, somewhat inclined outward, and gives attachment to a few 
fibres of the Levator anguli scapulae muscle. 
Inferior Angle (angulus inferior).-The inferior angle, thick and rough, is 
formed by the union of the vertebral and axillary borders, its outer surface 
affording attachment to the Teres major and frequently to a few fibres of the 
Latissimus dorsi. 
Anterior or Lateral Angle (angulus lateralis).-The anterior angle is the thickest 
part of the bone, and forms what is called the head of the scapula. The head THE SCAPULA 
175 
presents a shallow, pyriform, articular surface, the glenoid surface or cavity (cav- 
itas glenoidalis, from a socket), whose longest diameter is from above 
downward, and its direction outward and forward. It is broader below than 
above. Just above it is a rough surface, the supraglenoid tubercle or tuberosity 
(tuberositas supraglenoidalis), to which is attached the long tendon of the Biceps 
muscle. The glenoid cavity is covered with cartilage in the recent state; and 
its margins are slightly raised and give attachment to a fibro-cartilaginous struc- 
ture, the glenoid ligament, by which its cavity is deepened. The anatomical neck 
of the scapula (collum scapuloe) is the slightly depressed surface which surrounds 
the head; it is more distinct on the posterior than on the anterior surface, and 
below than above. In the latter situation it has arising from it a thick prominence, 
the coracoid process. 
The coracoid process (processus coracoideus), so called from its fancied resemblance 
to a crow's beak (xbpaz, a crow), is a thick, curved process of bone which arises by 
a broad base from the upper part of the neck of the scapula; it is directed at first 
upward and inward, then, becoming smaller, it changes its direction and passes for- 
ward and outward. The ascending portion, flattened from before backward, pre- 
sents in front a smooth, concave 
surface over which passes the 
Subscapularis muscle. The 
horizontal portion is flattened 
from above downward, its upper 
surface is convex and irregular, 
and gives attachment to the 
Pectoralis minor; its under sur- 
face is smooth; its inner border 
is rough, and gives attachment 
to the Pectoralis minor; its outer 
border is also rough for the 
coraco-acromial ligament, while 
the apex is embraced by the 
conjoined tendon of origin of 
the short head of the Biceps 
and of the Coraco-brachialis 
and gives attachment to the 
costo-coracoid ligament. At the 
inner side of the root of the 
coracoid process is a rough im- 
pression for the attachment of 
the conoid ligament; and run- 
ning from it obliquely forward 
and outward on the upper sur- 
face of the horizontal portion, 
an elevated ridge for the attach- 
ment of the trapezoid ligament. 
Structure.-In the head, pro- 
cesses, and all the thickened 
parts of the bone the scapula is composed of cancellous tissue, while in the rest of 
its extent it is composed of a thin layer of dense, compact tissue. The centre part 
of the supraspinous fossa and the upper part of the infraspinous fossa, but especially 
the former, are usually so thin as to be semitransparent; occasionally the bone is 
found wanting in this situation, and the adjacent muscles come into contact. 
Development (Fig. 128).-By seven or more centres: one for the body, two for 
the coracoid process, two for the acromion, one for the vertebral border, and one 
17th year. 
7 for Body 
8 week 
Fig. 128.-Plan of the development of the scapula. By seven 
centres. The epiphyses (except one for the coracoid process) 
appear from fifteen to seventeen years, and unite between twenty- 
two and twenty-five years of age. 176 
THE SKELETON 
for the inferior angle. Ossification of the body of the scapula commences about 
the second month of fcetal life by the formation of an irregular quadrilateral 
plate of bone immediately behind the glenoid cavity. This plate extends itself so 
as to form the chief part of the bone, the spine growing up from its posterior, 
surface about the third month. At birth a large part of the scapula is osseous, 
but the glenoid cavity, coracoid and acromion processes, the posterior border, and 
inferior angle are cartilaginous. From the fifteenth to the eighteenth month after 
birth ossification takes place in the middle of the coracoid process, which usually 
becomes joined with the rest of the bone at the time when the other centres make 
their appearance. Between the fourteenth and twentieth years ossification of the 
remaining centres takes place in quick succession, and in the following order: 
first, in the root of the coracoid process, in the form of a broad scale; secondly, 
near the base of the acromion process; thirdly, in the inferior angle and contigu- 
ous part of the posterior border; fourthly, near the extremity of the acromion; 
fifthly, in the posterior border. The acromion process, besides being formed of 
two separate nuclei, has its base formed by an extension into it of the centre of 
ossification which belongs to the spine, the extent of which varies in different 
cases. The two separate nuclei unite, and then join with the extension from the 
spine. These various epiphyses become joined to the bone between the ages of 
twenty-two and twenty-five years. Sometimes failure of union between the 
acromion process and spine occurs, the junction being effected by fibrous tissue 
or by an imperfect articulation; in some cases of supposed fracture of the acromion 
with ligamentous union it is probable that the detached segment was never united 
to the rest of the bone. The upper third of the glenoid cavity is usually ossified 
from a separate centre (subcoracoid) which makes its appearance between the 
tenth and eleventh years. Very often, in addition, an epiphysis appears for the 
lower part of the glenoid cavity. 
Articulations.-With the humerus and clavicle. 
Attachment of Muscles.-To seventeen: to the anterior surface, the Subscapu- 
laris; posterior surface, Supraspinatus, Infraspinatus; spine, Trapezius, Deltoid; 
superior border, Omo-hyoid; vertebral border, Serratus magnus, Levator anguli 
scapulae, Rhomboideus minor and major; axillary border, Triceps, Teres minor, 
Teres major; apex of glenoid cavity, long head of the Biceps; coracoid process, 
short head of the Biceps, Coraco-brachialis, Pectoralis minor; and to the inferior 
angle occasionally a few fibres of the Latissimus dorsi. 
Surface Form.-The only parts of the scapula which are truly subcutaneous are the spine 
and acromion process, but, in addition to these, the coracoid process, the internal or vertebral 
border and inferior angle, and, to a less extent, the axillary border, may be defined. The acro- 
mion process and spine of the scapula are easily felt throughout their entire length, forming, 
with the clavicle, the arch of the shoulder. The acromion can be ascertained to be connected 
to the clavicle at the acromio-clavicular joint by running the finger along it, its position being 
often indicated by an irregularity or bony outgrowth from the clavicle close to the joint. The 
acromion can be felt forming the point of the shoulder, and from this can be traced backward to 
join the spine of the scapula. The place of junction is usually denoted by a prominence, which is 
sometimes called the acromial angle. From here the spine of the scapula can be felt as a promi- 
nent ridge of bone, marked on the surface as an oblique depression, which becomes less and less 
distinct, and terminates a little external to the spinous processes of the vertebrae. Its termination is 
usually indicated by a slight dimple in the skin on a level with the interval between the third and 
fourth dorsal spines. Below this point the vertebral border of the scapula may be traced, running 
downward and outward, and thus diverging from the vertebral spines, to the inferior angle of 
the bone, which can be recognized, although covered by the Latissimus dorsi muscle. From 
this angle the axillary border can usually be traced through this thick muscular covering, form- 
ing, with the muscles, the posterior fold of the axilla. The coracoid process may be felt about 
an inch below the junction of the middle and outer thirds of the clavicle. Here it is covered by 
the anterior border of the deltoid and lies a little to the outer side of a slight depression which 
corresponds to the interval between the Pectoralis major and Deltoid muscles. When the arms 
are hanging by the side, the upper angle of the scapula corresponds to the upper border of the THE HUMERUS 
177 
second rib or the interval between the first and second dorsal spines, the inferior angle to the 
upper border of the eighth rib or the interval between the seventh and eighth dorsal spines. 
Surgical Anatomy.-Fractures of the body of the scapula are rare, owing to the mobility of the 
bone, the thick layer of muscles by which it is encased on both surfaces, and the elasticity of the 
ribs on which it rests. Fracture of the neck of the bone is also uncommon. The most frequent 
course of a line of fracture of the neck is from the suprascapular notch to the infraglenoid 
tubercle (surgical neck), and it derives its principal interest from its simulation to a subglenoid 
dislocation of the humerus. The diagnosis can be made by noting the alteration in the position 
of the coracoid process. A fracture of the neck external to, and not including, the coracoid 
process (anatomical neck) is said to occur, but it is exceedingly doubtful whether such an 
accident ever takes place. The acromion process is more frequently broken than any other 
part of the bone, and there is sometimes, in young subjects, a separation of the epiphysis. It 
is believed that many of the cases of supposed fracture of the acromion, with fibrous union, 
which have been found on post-mortem examination are really cases of imperfectly united 
epiphysis. Sir Astley Cooper believed that most fractures of this bone united by fibrous 
tissue, and the cause of this mode of union was the difficulty there was in keeping the frac- 
tured ends in constant apposition. The coracoid process is occasionally broken off, either from 
direct violence or perhaps, rarely, from muscular action. 
Tumors of various kinds grow from the scapula. Of the innocent form of tumors probably 
the osteomata are the most common. When an osteoma grows from the venter of the scapula, as it 
sometimes does, it is of the compact variety, such as usually grows from membrane-formed bones, 
as the bones of the skull. This would appear to afford evidence that this portion of the bone 
is formed from membrane, and not, like the rest of the bone, from cartilage. Sarcomatous 
tumors sometimes grow from the scapula, and may necessitate removal of the bone, with or 
without amputation of the upper limb. Removal of the upper limb with the scapula and the 
outer two-thirds of the clavicle is known as the interscapulo-thoracic amputation. The 
scapula may be partially resected or completely excised. There are several methods of com- 
plete excision. The bone may be excised by a T-shaped incision, and, the flaps being reflected, 
the removal is commenced from the posterior or vertebral border, so that the subscapular 
vessels which lie along the axillary border are among the last structures divided, and can be 
at once secured. 
THE ARM. 
The arm is that portion of the upper extremity which is situated between the 
shoulder and the elbow. Its skeleton consists of a single bone, the humerus. 
The Humerus or Upper Arm Bone (Figs. 129, 130). 
The humerus (from humerus, or more correctly umerus, the shoulder) is the 
longest and largest bone of the upper extremity; it presents for examination a 
shaft and two extremities. 
Upper Extremity.-The upper extremity presents a large, rounded head, 
joined to the shaft by a constricted portion, called the neck, and two other emi- 
nences, the greater and lesser tuberosities. 
The Head (caput humeri).--'The head, nearly hemispherical in form,1 is directed 
upward, inward, and slightly backward, and articulates with the glenoid cavity 
of the scapula; its surface is smooth and coated with cartilage in the recent state. 
The circumference of its articular surface is slightly constricted, and is termed 
the anatomical neck, in contradistinction to the constriction which exists below the 
tuberosities. The latter is called the surgical neck (collum chirurgicum), from its 
often being the seat of fracture. It should be remembered, however, that frac- 
ture of the anatomical neck does sometimes, though rarely, occur. 
Anatomical Neck (collum anatomicum).-The anatomical neck is obliquely 
directed, forming an obtuse angle with the shaft. It is more distinctly marked in 
the lower half of its circumference than in the upper half, where it presents a nar- 
row groove, separating the head from the tuberosities. Its circumference affords 
1 Though the head is nearly hemispherical in form, its margin, as Sir G. Humphry has shown, is by no means 
a true circle. Its greatest measurement is from the top of the bicipital groove in a direction downward, inward, 
and backward. Hence it follows that the greatest elevation of the arm can be obtained by rolling the articular 
surface in this direction-that is to say, obliquely upward, outward, and forward. 178 
THE SKELETON 
Surgical neck.- 
•SUPINATOR RADII LONGUS. 
• EXTENSOR CARPI RADIALIS 
LONGIOR. 
Common origin of 
FLEXOR CARPI RADIALIS. 
PALMARIS LONQUS. 
FLEXOR SUBLIMIS DIQITORUM. 
FLEXOR CARPI ULNARIS. 
F Common origin of 
EXTENSOR CARPI RADIALIS BREVIS, 
" COMMUNIS DIGITORUM. 
" MINIMI DIGITI. 
" CARPI ULNARIS. 
SUPINATOR BREVIS. 
Fig. 129.-Left humerus. Anterior view. THE HUMERUS 
179 
attachment to the capsular ligament and is perforated by numerous vascular 
foramina. 
Greater Tuberosity (tuberculum ma jus).-The greater tuberosity is situated on 
the outer side of the head and lesser tuberosity. Its upper surface is rounded and 
marked by three flat facets, separated by two slight ridges: the highest facet gives 
attachment to the tendon of the Supraspinatus; the middle one, to the Infra- 
spinatus; the inferior facet and the shaft of the bone below it, to the Teres minor. 
The outer surface of the great tuberosity is convex, rough, and continuous with 
the outer side of the shaft. 
Lesser Tuberosity (tuberculum minus).-The lesser tuberosity is more promi- 
nent, although smaller than the greater: it is situated in front of the head, and 
is directed inward and forward. Its summit presents a prominent facet for the 
insertion of the tendon of the Subscapularis muscle. The tuberosities are sepa- 
rated from one another by a deep groove, the bicipital groove (sulcus intertuber- 
cular is). This groove lodges the long tendon of the Biceps muscle, with which 
runs a branch of the anterior circumflex artery. It commences above between 
the two tuberosities, passes obliquely downward and a little inward, and ter- 
minates at the junction of the upper with the middle third of the bone. It is 
deep and narrow at the commencement, and becomes shallow and a little broader 
as it descends. Its borders are called, respectively, the external or posterior bicipital 
ridge (crista tuberculi majoris) and the internal or anterior bicipital ridge (crista 
tuberculi minoris), and form the upper part of the anterior and internal borders 
of the shaft of the bone. In the recent state it is covered with a thin layer of 
cartilage, lined by a prolongation of the synovial membrane of the shoulder- 
joint, and receives the tendon of insertion of the Latissimus dorsi muscle. 
The Shaft (corpus humeri).-The shaft of the humerus is almost cylindrical in 
the upper half of its extent, prismatic and flattened below, and presents three 
borders and three surfaces for examination. 
Anterior Border.-The anterior border runs from the front of the great tuber- 
osity above to the coronoid depression below, separating the internal from the 
external surface. Its upper part is very prominent and rough, and forms the 
outer lip of the bicipital groove. It is sometimes called the posterior bicipital, 
external bicipital, or pectoral ridge (crista tuberculi majoris), and serves for the 
attachment of the tendon of the Pectoralis major. About its centre it forms the 
anterior boundary of the rough deltoid eminence or impression (tuberositas deltoidea); 
below, it is smooth and rounded, affording attachment to the Brachialis anticus 
muscle. 
External Border (margo lateralis).-The external border runs from the back 
part of the greater tuberosity to the external condyle, and separates the external 
from the posterior surface. It is rounded and indistinctly marked in its upper 
half, serving for the attachment of the lower part of the insertion of the Teres 
minor muscle, and below this of the external head of the Triceps muscle; its centre is 
traversed by a broad but shallow, oblique depression, the musculo-spiral groove 
(sulcus nervi radialis); its lower part is marked by a prominent, rough margin, 
a little curved from behind forward, the external supracondylar or epicondylic ridge 
(margo lateralis), which presents an anterior lip for the attachment of the Supin- 
ator longus above and Extensor carpi radialis longior below, a posterior lip for 
the Triceps, and an intermediate space for the attachment of the external inter- 
muscular septum. 
Internal Border (margo medialis).-The internal border extends from the lesser 
tuberosity to the internal condyle. Its upper third is marked by a prominent 
ridge, forming the posterior lip of the bicipital groove, and gives attachment to 
the tendon of the Teres major. About its centre is an impression for the attach- 
ment of the Coracobrachialis, and just below this is seen the entrance of the 180 
THE SKELETON 
nutrient canal, directed downward. Sometimes 
there is a second canal situated at the com- 
mencement of the musculo-spiral groove, for a 
nutrient artery derived from the superior pro- 
funda branch of the brachial artery. The in- 
ferior third of this border is raised into a slight 
ridge, the internal supracondylar or epicondylic 
ridge (margo medialis), which becomes very 
prominent below; it presents an anterior lip 
for the attachment of the Brachialis anticus 
muscle, a posterior lip for the internal head of 
the Triceps muscle, and an intermediate space 
for the attachment of the internal intermuscular 
septum. 
External Surface (facies anterior lateralis).- 
The external surface is directed outward above, 
where it is smooth, rounded, and covered by the 
Deltoid muscle; forward and outward below, 
where it is slightly concave from above down- 
ward, and gives origin to part of the Brachi- 
alis anticus muscle. About the middle of this 
surface is seen a rough, triangular impression 
for the insertion of the Deltoid muscle, deltoid 
impression (tuberositas deltoidea)', and below it 
the musculo-spiral groove, directed obliquely 
from behind, forward and downward, and trans- 
mitting the musculo-spiral nerve and superior 
profunda artery. 
Internal Surface (facies anterior medialis).- 
The internal surface, less extensive than the ex- 
ternal, is directed inward above, forward and 
inward below; at its upper part it is narrow and 
forms the floor of the bicipital groove: to it is 
attached the Latissimus dorsi. The middle part 
of this surface is slightly rough for the attach- 
ment of some of the fibres of the tendon of 
insertion of the Coraco-brachialis; its lower 
part is smooth, concave from above downward, 
and gives attachment to the Brachialis anticus 
muscle.1 A little below the middle of the shaft 
is the nutrient foramen (foramen nutricium). 
1 A small, hook-shaped process of bone, the supracondylar pro- 
cess, varying from '/io to 3/< of an inch in length, is not infrequently 
found projecting from the inner surface of the shaft of the humerus 
two inches above the internal condyle. It is curved downward, 
forward, and inward, and its pointed extremity is connected to 
the internal border, just above the inner condyle, by a ligament 
or fibrous band, which gives origin to a portion of the Pronator 
radii teres; through the arch completed by this fibrous band the 
median nerve and brachial artery pass when these structures 
deviate from their usual course. Sometimes the nerve alone is 
transmitted through it, or the nerve may be accompanied by the 
ulnar artery in cases of high division of the brachial. A well-marked 
groove is usually found behind the process in which the nerve and 
artery are lodged. This space is analogous to the supracondyloid 
foramen in many animals, and probably serves in them to protect 
the nerve and artery from compression during the contraction 
of the muscles in this region. A detailed account of this process 
is given by Dr. Struthers, in his Anatomical and Physiological 
Observations, p. 202. An accessory portion of the Coraco-bra- 
chialis muscle is frequently connected with this process, according 
to Mr. J. Wood (Journal of Anat, and Phys., No. 1, November, 
1866, p. 47). 
Fig. 130.-Left humerus. Posterior surface. THE HUMERUS 
This leads into a nutrient canal (canalis nutricius), which is directed toward the 
elbow-joint (distally). 
Posterior Surface (facies posterior).-The posterior surface (Fig. 130) appears 
somewhat twisted, so that its upper part is directed a little inward, its lower part 
backward and a little outward. Nearly the whole of this surface is covered by 
the external and internal heads of the Triceps, the former of which is attached 
to its upper and outer part, the latter to its inner and back part, the two being 
separated by the musculo-spiral groove. 
Lower Extremity.-The lower extremity is flattened from before back- 
ward, and curved slightly forward; it terminates below in a broad, articular 
surface which is divided into two parts by a slight ridge. Projecting on 
either side are the external and internal condyles (epicondylus lateralis and 
epicondylus medialis). By some anatomists the external condyle is called the 
external epicondyle and the internal condyle is called the internal epicondyle. 
Others call the internal condyle the epitrochlea. The articular surface extends a 
little lower than the condyles, and is curved slightly forward, so as to occupy the 
more anterior part of the bone; its greatest breadth is in the transverse diameter, 
and it is obliquely directed, so that its inner extremity occupies a lower level than 
the outer. The outer portion of the articular surface presents a smooth, rounded 
eminence, which has received the name of the capitellum, or radial head of the 
humerus (capitulum humeri); it articulates with the cup-shaped depression on 
the head of the radius, and is limited to the front and lower part of the bone, 
not extending as far back as the other portion of the articular surface. On the 
inner side of this eminence is a shallow groove, in which is received the inner 
margin of the head of the radius. Above the front part of the capitellum is a 
slight depression, the radial fossa (fossa radialis), which receives the anterior 
border of the head of the radius when the forearm is flexed. The inner por- 
tion of the articular surface, the trochlea (trochlea humeri), presents a deep 
depression between two well-marked borders. This surface is convex from 
before backward, concave from side to side, and occupies the anterior, lower, 
and posterior parts of the bone. The external border, less prominent than the 
internal, corresponds to the interval between the radius and the ulna. The 
internal border is thicker, more prominent, and consequently of greater length, 
than the external. The grooved portion of the articular surface fits accurately 
within the greater sigmoid cavity of the ulna: it is broader and deeper on the pos- 
terior than on the anterior aspect of the bone, and is inclined obliquely from 
behind forward and from without inward. Above the front part of the trochlear 
surface is seen a smaller depression, the coronoid fossa (fossa coronoidea), which 
receives the coronoid process of the ulna during flexion of the forearm. Above 
the back part of the trochlear surface is a deep, triangular depression, the 
olecranon fossa (fossa olecrani), in which is received the summit of the olecranon 
process in extension of the forearm. These fossae are separated from one another by 
a thin, transparent lamina of bone, which is sometimes perforated by a foramen, 
the supratrochlear foramen; their upper margins afford attachment to the anterior 
and posterior ligaments of the elbow-joint, and they are lined, in the recent state, 
by the synovial membrane of this articulation. The articular surfaces, in the 
recent state, are covered with a thin layer of cartilage. The external epicon- 
dyle (epicondylus lateralis) is a small, tubercular eminence, less prominent 
than the internal, curved a little forward, and giving attachment to the external 
lateral ligament of the elbow-joint, and to a tendon common to the origin of some 
of the extensor and supinator muscles. The internal epicondyle (epitrochlea or 
epicondylus medialis), larger and more prominent, and therefore more liable to 
fracture, than the external, is directed a little backward: it gives attachment to 
the internal lateral ligament, to the Pronator radii teres, and to a tendon common 
181 182 
THE SKELETON 
to the origin of some of the flexor muscles of the forearm. The ulnar nerve runs 
in a groove, the ulnar groove {sulcus nervi ulnaris), at the back of the internal 
condyle, or between it and the olecranon process. These condyles are directly 
continuous above with the external and internal supracondylar ridges. 
Structure.-The extremities consist of cancellous tissue, covered with a thin 
compact layer; the shaft is composed of a cylinder of compact tissue, thicker at 
the centre than at the extremities, and hollowed out by a large medullary canal, 
which extends along its whole length. In the head of the humerus the plates 
of the cancellous tissue are arranged in 
curves (Fig. 131) known as pressure curves. 
Most of the bone-plates are at right angles 
to the plane of the articular surface (the 
lines of greatest pressure), and they are 
bound together by other bone-fibres, which 
usually correspond to the plane of the 
Epiphyses of head and 
tuberosities blend at 
5th year, and unite 
with shaft at 20th 
year. 
Unites with shaft 
at 18th year. 
Fig. 131.-Diagram showing the architecture of the supe- 
rior extremity of the humerus. (Poirier and Charpy.) 
Fig. 132.-Plan of the development of the 
humerus by seven centres. 
articulation (the lines of greatest tension). This arch-like arrangement strength- 
ens the head of the bone, and it is further strengthened by the binding fibres. 
Development.-By seven, or occasionally eight, centres (Fig. 132): one for the 
shaft, one for the head, one for the tuberosities, one for the radial head, one for 
the trochlear portion of the articular surface, and one for each condyle. The 
nucleus for the shaft appears near the centre of the bone in the eighth week, and 
soon extends toward the extremities. At birth the humerus is ossified nearly in 
its whole length, the extremities remaining cartilaginous. During the first year, 
sometimes even before birth, ossification commences in the head of the bone, and 
during the third year the centre for the tuberosities makes its appearance, usually 
by a single ossific point, but sometimes, according to Beclard, by one for each 
tuberosity, that for the lesser being small and not appearing until the fifth year. 
By the sixth year the centres for the head and tuberosities have increased in size 
and become joined, so as to form a single large epiphysis. 
The lower end of the humerus is developed in the following manner: At the 
end of the second year ossification commences in the capitellum, and from this 
point extends inward, so as to form the chief part of the articular end of the bone, THE HUMERUS 
183 
the centre for the inner part of the trochlea not appearing until about the age of 
twelve. Ossification commences in the internal condyle about the fifth year, and 
in the external one not until about the thirteenth or fourteenth year. About six- 
teen or seventeen years the outer condyle and both portions of the articulating 
surface (which have already joined) unite with the shaft; at eighteen years the inner 
condyle becomes joined; while the upper epiphysis, although the first formed, is 
not united until about the twentieth year. 
Articulations.-With the glenoid cavity of the scapula and with the ulna and 
radius. 
Attachment of the Muscles.-To twenty-four: to the greater tuberosity, the 
Supraspinatus, Infraspinatus, and Teres minor; to the lesser tuberosity, the 
Subscapularis; to the anterior bicipital ridge, the Pectoralis major; to the posterior 
bicipital ridge, the Teres major; to the bicipital groove, the Latissimus dorsi; to 
the shaft, the Deltoid, Coraco-brachialis, Brachialis anticus, external and internal 
heads of the Triceps; to the internal condyle, the Pronator radii teres, and common 
tendon of the Flexor carpi radialis, Palmaris longus, Flexor sublimis digitorum, 
and Flexor carpi ulnaris; to the external condyloid ridge, the Supinator longus 
and Extensor carpi radialis longior; to the external condyle, the common tendon 
of the Extensor carpi radialis brevior, Extensor communis digitorum, Extensor 
minimi digiti, Extensor carpi ulnaris, and Supinator brevis; to the back of the 
external condyle, the Anconeus. 
Surface Form.-The humerus is almost entirely clothed by the muscles which surround it, 
and the only parts of this bone which are strictly subcutaneous are small portions of the 
internal and external condyles. In addition to these, the tuberosities and a part of the head 
of the bone can be felt under the skin and muscles by which they are covered. Of these the 
greater tuberosity forms the most prominent bony point of the shoulder, extending beyond the 
acromion process and covered by the Deltoid muscle. It influences materially the surface form 
of the shoulder. It is best felt while the arm is lying loosely by the side; if the arm be raised, 
it recedes from under the finger. The lesser tuberosity, directed forward and inward, is to be 
felt to the inner side of the greater tuberosity, just below the acromio-clavicular joint. Between 
the two tuberosities lies the bicipital groove. This can be defined by placing the finger and 
making firm pressure just internal to the greater tuberosity; then, by rotating the humerus, the 
groove will be felt to pass under the finger as the bone is rotated. With the arm abducted from 
the side, by pressing deeply in the axilla the lower part of the head of the bone is to be felt. 
On each side of the elbow-joint, and just above it, the internal and external condyles of the 
bone are to be felt. Of these the internal is the more prominent, but the ridge passing upward 
from it, the internal condyloid ridge, is much less marked than the external, and, as a rule, is 
not to be felt. Occasionally, however, we find along this border the hook-shaped process men- 
tioned above. The external condyle is most plainly to be seen during semiflexion of the fore- 
arm, and its position is indicated by a depression between the attachment of the adjacent mus- 
cles. From it is to be felt a strong bony ridge running up the outer border of the shaft of the 
bone. This is the external supracondylar ridge; it is concave forward, and corresponds with 
the curved direction of the lower extremity of the humerus. 
Surgical Anatomy.-There are several points of surgical interest connected with the 
humerus. First, as regards its development. The upper end, though the first to ossify, is the 
last to join the shaft, and the length of the bone is mainly due to growth from this upper 
epiphysis. Hence, in cases of amputation of the arm in young subjects the humerus continues 
to grow considerably, and the end of the bone, which immediately after the operation was cov- 
ered with a thick cushion of soft tissue, begins to project, thinning the soft parts and rendering 
the stump conical. This may necessitate another operation, which consists in the removal of a 
couple of inches or so of the bone, and even after this operation a recurrence of the conical stump 
may take place. 
There are several points of surgical interest in connection with fractures. First, as regard 
their causation: the bone may be broken by direct or indirect violence like the other long bones, 
but, in addition to this, it is probably more frequently fractured by muscular action than any 
other of this class of bone in the body. It is usually the shaft, just below the insertion of the 
Deltoid, which is thus broken. Mr. Pick has seen the accident happen from throwing a stone, and 
in an apparently healthy adult from cutting a piece of hard "cake tobacco" on a table. In this 
latter case there was no disease of the bone that could be discovered. Fractures of the upper 
end may take place through the anatomical neck, through the surgical neck, or separation of the 184 
THE SKELETON 
greater tuberosity may occur. Fracture of the anatomical neck is a very rare accident; in fact, 
it is doubted by some whether it ever occurs. These fractures are usually considered to be 
intracapsular, but they are probably partly within and partly without the capsule, as the lower 
part of the capsule is inserted some little distance below the anatomical neck, while the upper 
part is attached to it. They may be impacted or non-impacted. In most cases there is little or 
no displacement on account of the capsule, in whole or in part, remaining attached to the lower 
fragment. But occasionally a very remarkable alteration in position takes place; the upper 
fragment turns on its own axis, so that the cartilaginous surface of the head rests against the 
upper end of the lower fragment. When the fractured end is entirely separated from all its 
surroundings, its vascular supply must be entirely cut off, and one would expect it, theoretically, 
to necrose. But this must be exceedingly rare, for Gurlt was unable to find a single authenti- 
cated case recorded. Separation of the upper epiphysis of the humerus sometimes occurs in the 
young subject, and is marked by a characteristic deformity by which the lesion may be at once 
recognized. This consists in the presence of an abrupt projection at the front of the joint some 
short distance below the coracoid process, caused by the upper end of the lower fragment. In 
fractures of the shaft of the humerus the lesion may take place at any point, but appears to be 
more common in the lower than in the upper part of the bone. The points of interest in con- 
nection with these fractures are: (1) That the musculo-spiral nerve may be injured as it lies in the 
groove on the bone, or may become involved in the callus which is subsequently thrown out; 
and (2) the frequency of non-union. This is believed to be more common in the humerus than 
jn any other bone, and various causes have been assigned for it. It would seem most probably 
to be due to the difficulty that there is in fixing the shoulder-joint and the upper fragment, and 
possibly the elbow-joint and lower fragment also. Other causes which have been assigned 
for the non-union are: (1) That in attempting passive motion of the elbow-joint to overcome 
any rigidity which may exist, the movement does not take place at the articulation, but at the 
seat of fracture; or that the patient, in consequence of the rigidity of the elbow, in attempting 
to flex or extend the forearm moves the fragment and not the joint. (2) The presence of small 
portions of muscular tissue between the broken ends. (3) Want of support to the elbow, so 
that the weight of the arm tends to drag the lower fragment away from the upper. An impor- 
tant distinction to make in fractures of the lower end of the humerus is between those that 
involve the elbow-joint and those which do not; the former are always serious, as they may lead 
to stiffness of the joint and impairment of the utility of the limb. They include the T-shaped 
fracture and oblique fractures which involve the articular surface. The fractures which do not 
involve the joint are the transverse above the condyles and the so-called epitrochlear fracture, 
in which the tip of the internal condyle is broken off, generally by direct violence. 
Under the head of separation of the lower epiphysis two separate injuries have been described: 
One where the whole of the four ossific centres which form the lower extremity of the bone are 
separated from the shaft; and secondly, where the articular portion is alone separated, the two 
condyles remaining attached to the shaft of the bone. The epiphysial line between the shaft 
and lower end runs across the bone just above the tips of the condyles, a point to be borne in 
mind in performing the operation of excision. 
Tumors originating from the humerus are of frequent occurrence. A not uncommon place 
for a chondroma to grow from is the shaft of the bone somewhere in the neighborhood of the 
insertion of the deltoid. Sarcomata frequently grow from this bone. 
THE FOREARM. 
The forearm is that portion of the upper extremity which is situated between 
the elbow and the wrist. Its skeleton is composed of two bones, the ulna and 
radius. 
The Ulna or Elbow Bone. 
The ulna (Figs. 133 and 134), so called from its forming the elbow is a 
long bone, prismatic in form, placed at the inner side of the forearm, parallel with 
the radius. It is the larger and longer of the two bones. Its upper extremity, of 
great thickness and strength, forms a large part of the articulation of the elbow- 
joint; it diminishes in size from above downward, its lower extremity being very 
small, and excluded from the wrist-joint by the interposition of an interarticular 
fibro-cartilage. It is divisible into a shaft and two extremities. 
Upper Extremity.-The upper extremity, the strongest part of the bone, 
presents for examination two large, curved processes, the olecranon process and THE ULNA 
185 
Radius. 
FLEXOR DlQITORUM_ 
SUBLIMlS. 
PRONATOR 
RADII TERES. 
Occasional or igin of 
FLEXOR LONGUS POLLICIS. 
Radial origin 0/flexor 
DIQITORUM SUBLIMIS. 
ISUPINATOR LONGUS. 
Styloid process. 
Groove for ext. ossis 
METAOARPl POLLICIS 
I and EXT BREV. POLL 
Fig. 133.-Bones of the left forearm. Anterior surface. 
Styloid process. THE SKELETON 
186 
the coronoid process; and two concave, articular cavities, the greater and lesser 
sigmoid cavities. 
Olecranon Process (olecranon).-The olecranon process ((b/.s^, elbow; xpaviov, 
head) is a large, thick, curved eminence situated at the upper and back part of 
the ulna. It is curved forward at the summit so as to present a prominent tip 
which is received into the olecranon fossa of the humerus in extension of the fore- 
arm; its base being contracted where it joins the shaft. This is the narrowest part 
of the upper end of the ulna, and, consequently, the most usual seat of fracture. 
The posterior surface of the olecranon, directed backward, is triangular, smooth, 
subcutaneous, and covered by a bursa. Its upper surface is of a quadrilateral 
form, marked behind by a rough impression for the attachment of the Triceps 
muscle; and in front, near the margin, by a slight transverse groove for the 
attachment of part of the posterior ligament of the elbow-joint. Its interior sur- 
face is smooth, concave, covered with cartilage in the recent state, and forms the 
upper and back part of the great sigmoid cavity. The lateral borders present 
a continuation of the same groove that was seen on the margin of the superior 
surface; they serve for the attachment of ligaments-viz., the back part of the 
internal lateral ligament internally, the posterior ligament externally. To the 
inner border is also attached a part of the Flexor carpi ulnaris, while to the outer 
border is attached the Anconeus muscle. 
Coronoid Process (processus coronoideus).-The coronoid process (xopibw], any- 
thing hooked like a crow's beak) is a triangular eminence of bone which projects 
horizontally forward from the upper and front part of the ulna. Its base is con- 
tinuous with the shaft, and of considerable strength; so much so that fracture of 
it is an accident of rare occurrence. Its apex is pointed, slightly curved upward, 
and is received into the coronoid depression of the humerus in flexion of the forearm. 
Its upper surface is smooth, concave, and forms the lower part of the greater sig- 
moid cavity. The under surface is concave. At the junction of this surface with 
the shaft is a rough eminence, the tubercle of the ulna (tuberositas ulna;), for the 
attachment of the oblique ligament of the superior radio-ulnar articulation and the 
Brachialis anticus muscle. Its outer surface presents a narrow, oblong, articular 
depression, the lesser sigmoid cavity. The inner surface, by its prominent, free 
margin, serves for the attachment of part of the internal lateral ligament. At 
the front part of this surface is a small, rounded eminence for the attachment of 
one head of the Flexor sublimis digitorum; behind the eminence, a depression for 
part of the origin of the Flexor profundus digitorum; and, descending from the 
eminence, a ridge which gives attachment to one head of the Pronator radii teres. 
Generally, the Flexor longus pollicis has an origin from the lower part of the 
coronoid process by a rounded bundle of muscular fibres. 
Greater Sigmoid Cavity (incisura semilunaris).-The greater sigmoid cavity, so 
called from its resemblance to the old shape of the Greek letter 2', is a semi- 
lunar depression of large size, formed by the olecranon and coronoid processes, 
and serving for articulation with the trochlear surface of the humerus. About 
the middle of either lateral border of this cavity is a notch which contracts it 
somewhat, and serves to indicate the junction of the two processes of which it is 
formed. The cavity is concave from above downward, and divided into two 
lateral parts by a smooth, elevated ridge which runs from the summit of the 
olecranon to the tip of the coronoid process. Of these two portions, the internal 
is the larger, and is slightly concave transversely; the external portion is convex 
above, slightly concave below. The articular surface, in the recent state, is 
covered with a thin layer of cartilage. 
Lesser Sigmoid Cavity (incisura radialis).-The lesser sigmoid cavity is a narrow, 
oblong, articular depression, placed on the outer side of the coronoid process, and 
receives the lateral articular surface of the head of the radius. It is concave from THE ULNA 
187 
Ulna. 
Radius. 
■FLEXOR SUBLIMI3 DIGITORUM. 
Posterior border of ulna: giving attachment to an aponeurosis common to- 
EXTENSOR CARPI ULNARIS. 
FLEXOR CARPI ULNARIS. 
FLEXOR PROFUNDUS DIGITORUM. 
For EXTENSOR CARPI ULNARI9. 
Vor EXTENSOR MINIMI DIGITI. 
For EXT. CARPI RAD. LONGIOR. 
EXTENSOR CARPI RADIALIS BREVIOR. 
EXTENSOR LONGOS POLLICIS. 
For 
EXTENSOR INDICIS. 
EXTENSOR COMMUNIS DIGITORUM. 
Fig. I*-Bones of the left forearm. HPosterior surface. THE SKELETON 
188 
before backward, and its extremities, which are prominent, serve for the attach- 
ment of the orbicular ligament. In the recent state it is covered with a thin layer 
of cartilage. 
The Shaft (corpus ulnae).-The shaft, at its upper part, is prismatic in form, and 
curved from behind forward and from without inward, so as to be convex behind 
and externally; its central part is cpiite straight; its lower part rounded, smooth, 
and bent a little outward; it tapers gradually from above downward, and presents 
for examination three borders and three surfaces. 
Anterior or Palmar Border (margo volaris).-The anterior border commences 
above at the prominent inner angle of the coronoid process, and terminates below 
in front of the styloid process. It is well marked above, smooth and rounded in 
the middle of its extent, and affords attachment to the Flexor profundus digitorum: 
its lower fourth, marked off from the rest of the border by the commencement of 
an oblique ridge on the anterior surface, serves for the attachment of the Pronator 
quadratus. It separates the anterior from the internal surface. 
Posterior or Dorsal Border (margo dorsalis).-The posterior border commences 
above at the apex of the triangular subcutaneous surface at the back part of the 
olecranon, and terminates below at the back part of the styloid process; it is well 
marked in the upper three-fourths, and gives attachment to the aponeurosis com- 
mon to the Flexor carpi ulnaris, the Extensor carpi ulnaris, and the Flexor pro- 
fundus digitorum muscles; its lower fourth is smooth and rounded. This border 
separates the internal from the posterior surface. 
External or Interosseous Border (crista interossea).-The external or interosseous 
border commences above by the union of two lines, which converge one from each 
extremity of the lesser sigmoid cavity, enclosing between them a triangular space 
for the attachment of part of the Supinator brevis. The external line is the 
crista m. supinatoris. The interosseous border of the ulna terminates below at 
the middle of the head of the ulna. Its two middle fourths are very prominent; 
its lower fourth is smooth and rounded. This border gives attachment to the 
interosseous membrane, and separates the anterior from the posterior surface. 
Anterior or Palmar Surface (facies volaris).-The anterior surface, much broader 
above than below, is concave in the upper three-fourths of its extent, and affords 
attachment to the Flexor profundus digitorum; its lower fourth, also concave, is 
covered by the Pronator quadratus. The lower fourth is separated from the 
remaining portion of the bone by a prominent ridge, directed obliquely from 
above downward and inward; this ridge, the oblique or pronator ridge, marks the 
extent of attachment of the Pronator quadratus. At the junction of the upper 
with the middle third of the bone is the nutrient foramen (foramen nutricium). 
It opens into the nutrient canal (canalis nutricius), which is directed obliquely 
upward and inward (proximally). 
Posterior or Dorsal Surface (faciesdorsalis).-The posterior surface, directed back- 
ward and outward, is broad and concave above, somewhat narrower and convex in 
the middle of its course, narrow, smooth, and rounded below. It presents, above, an 
oblique ridge, which runs from the posterior extremity of the lesser sigmoid cavity, 
downward to the posterior border; the triangular surface above this ridge receives 
the insertion of the Anconeus muscle, whilst the upper part of the ridge itself affords 
attachment to the Supinator brevis. The surface of bone below this is subdivided 
by a longitudinal ridge, sometimes called the perpendicular line, into two parts; 
the internal part is smooth, and covered by the Extensor carpi ulnaris; the exter- 
nal portion, wider and rougher, gives attachment from above downward to part 
of the Supinator brevis, the Extensor ossis metacarpi pollicis, the Extensor longus 
pollicis, and the Extensor indicis muscles. 
Internal Surface (facies medial is).-The internal surface is broad and concave 
above, narrow and convex below. It gives attachment by its upper three-fourths THE ULNA 
189 
to the rlexor profundus digitorum muscle: its lower fourth is subcutaneous. 
The anterior and the inner surfaces constitute the flexor surface. 
Lower Extremity.-The lower extremity of the ulna is of small size, and 
excluded from the articulation of the wrist-joint. It presents for examination two 
eminences, the outer and larger of which is a rounded, articular eminence, termed 
the head of the ulna (capitulum ulnae}, the inner, narrower and more projecting, 
is a non-articular eminence, the styloid process (processus styloideus}. The head 
presents an articular facet, part of which, of an oval or semilunar form, is 
directed downward, and articulates with the upper surface of the interarticular 
fibro-cartilage which separates it from the wrist-joint; the remaining portion, 
directed outward, is narrow, convex, and received into the sigmoid cavity of the 
radius. The peripheral margin of the portion of the head which articulates with 
the ulna is called the articular circumference (circumjerentia articularis}. The 
styloid process projects from the inner and back part of the bone, and descends 
a little lower than the head, terminating in a rounded summit, which affords 
attachment to the internal lateral ligament of the wrist. The head is separated 
from the styloid process by a depression for the attachment of the triangular 
interarticular fibro-cartilage; and behind, by a shallow groove for the passage of 
the tendon of the Extensor carpi ulnaris. 
Structure.-Similar to that of the other long bones. 
Development.-By three centres: one for the shaft, one for the inferior extrem- 
ity, and one for the olecranon (Fig. 135). Ossification commences near the 
middle of the shaft about the eighth week, and 
soon extends through the greater part of the bone. 
At birth the ends are cartilaginous. About the 
fourth year a separate osseous nucleus appears in 
the middle of the head, which soon extends into the 
styloid process. About the tenth year ossific matter 
appears in the olecranon near its extremity, the chief 
part of this process being formed from an extension 
of the shaft of the bone into it. At about the six- 
teenth year the upper epiphysis becomes joined, and 
at about the twentieth year the lower one. 
Articulations.-With the humerus and radius. 
Attachment of Muscles.-To sixteen: to the ole- 
cranon, the Triceps, Anconeus, and one head of the 
Flexor carpi ulnaris. To the coronoid process, the 
Brachialis anticus, Pronator radii teres, Flexor sub- 
limis digitorum, and Flexor profundus digitorum; 
generally also the Flexor longus pollicis. To the 
shaft, the Flexor profundus digitorum, Pronator 
quadratus, Flexor carpi ulnaris, Extensor carpi 
ulnaris, Anconeus, Supinator brevis, Extensor ossis 
metacarpi pollicis, Extensor longus pollicis, and 
Extensor indicis. 
Appears at 
10th year. 
Olecranon. 
■Joins shaft at 
16th year. 
Appears at 
4th year. 
Joins shaft at 
20th year. 
Fig. 135.-Plan of the development 
of the ulna. By three centres. 
Inferior extremity. 
Surface Form.-The most prominent part of the ulna on 
the surface of the body is the olecranon process, which can 
always be felt at the back of the elbow-joint. When the forearm is flexed, the upper quadri- 
lateral surface can be felt, directed backward; during extension it recedes into the olecranon 
fossa, and the contracting fibres of the triceps prevent its being perceived. At the back of 
the olecranon is the smooth, triangular, subcutaneous surface, which below is continuous 
with the posterior border of the shaft of the bone, and felt in every position of the forearm. 
During extension the upper border of the olecranon is slightly above the level of the internal 
condyle, and the process itself is nearer to this condyle than the outer one. Running down 
the back of the forearm, from the apex of the triangular surface which forms the posterior 190 
THE SKELETON 
surface of the olecranon, is a prominent ridge of bone, the posterior border of the ulna. 
This is to be felt throughout the entire length of the shaft of the bone, from the olecranon 
above to the styloid process below. As it passes down the forearm it pursues a sinuous course 
and inclines to the inner side, so that, though it is situated in the middle of the back of 
the limb above, it is on the inner side of the wrist at its termination. It becomes rounded off 
in its lower third, and may be traced below to the small, subcutaneous surface of the styloid 
process. Internal to this border the lower fourth of the inner surface is to be felt. The styloid 
process is to be felt as a prominent tubercle of bone, continuous above with the posterior sub- 
cutaneous border of the ulna, and terminating below in a blunt apex, which lies a little internal 
and behind, but on a level with, the wrist-joint. The styloid process is best felt when the hand 
is in the same line as the bones of the forearm, and in a position midway between supination 
and pronation. If the forearm is pronated while the finger is placed on the process, it will be 
felt to recede, and another prominence of bone will appear just behind and above it. This 
is the head of the ulna, which articulates with the lower end of the radius and the triangular 
interarticular fibro-cartilage, and now projects between the tendons of the Extensor carpi ulnaris 
and the Extensor minimi digiti muscles. 
The Radius. 
The radius (radius, a ray, or spoke of a wheel) is so called because it is the 
rotary bone of the forearm. It is situated on the outer side of the forearm, lying 
side by side with the ulna, which exceeds it in length and size (Figs. 133 and 
134). Its upper end is small, and forms only a small part of the elbow-joint; 
but its lower end is large, and forms the chief part of the wrist. It is one of the 
long bones, prismatic in form, slightly curved longitudinally, and, like other 
long bones, has a shaft and two extremities. 
Upper Extremity.-The upper extremity presents a head, neck, and tuberosity. 
The Head.-The head (capitulum radii) is of a cylindrical form, depressed on 
its upper surface into a shallow cup (fovea capituli radii), which articulates with 
the capitellum or radial head of the humerus. In the recent state it is covered 
with a layer of cartilage which is thinnest at its centre. Around the circumference 
of the head is a smooth, articular surface (circumferentia articularis), broad inter- 
nally where it articulates with the lesser sigmoid cavity of the ulna; narrow in 
the rest of its circumference, where it rotates within the orbicular ligament. It 
is coated with cartilage in the recent state. The head is supported on a round, 
smooth, and constricted portion of bone, called the neck (collum radii), which 
presents, behind, a slight ridge, for the attachment of part of the Supinator brevis. 
Beneath the neck, at the inner and front aspect of the bone, is a rough eminence, 
the bicipital tuberosity (tuberositas radii). Its surface is divided into two parts by 
a vertical line-a posterior, rough portion, for the insertion of the tendon of the 
Biceps muscle; and an anterior, smooth portion, on which a bursa is interposed 
between the tendon and the bone. 
The Shaft (corpus radii).-The shaft of the bone is prismoid in form, narrower 
above than below, and slightly curved, so as to be convex outward. It presents 
three surfaces, separated by three borders. 
Anterior or Palmar Border (margo volaris).-The anterior border extends from 
the lower part of the tuberosity above to the anterior part of the base of the styloid 
process below. It separates the anterior from the external surface. Its upper 
third is very prominent; and from its oblique direction, downward and outward, 
has received the name of the oblique line of the radius. It gives attachment exter- 
nally to the Supinator brevis, internally to the Flexor longus pollicis, and between 
these to the Flexor sublimis digitorum. The middle third of the anterior border 
is indistinct and rounded. Its lower fourth is sharp, prominent, affords attach- 
ment to the Pronator quadratus and to the posterior annular ligament of the wrist, 
and terminates in a small tubercle at the base of the styloid process, into which 
is inserted the tendon of the Supinator longus. THE RADIUS 
191 
Posterior or Dorsal Border (margo dorsalis).-The posterior border commences 
above at the back part of the neck of the radius, and terminates below at the 
posterior part of the base of the styloid process; it separates the posterior from 
the external surface. It is indistinct above and below, but well marked in the 
middle third of the bone. 
Internal or Interosseous Border {crista interossed).-The internal or interosseous 
border commences above at the back part of the tuberosity, where it is rounded 
and indistinct, becomes sharp and prominent as it descends, and at its lower part 
divides into two ridges, which descend to the anterior and posterior margins of 
the sigmoid cavity. This border separates the anterior from the posterior sur- 
face, and has the interosseous membrane attached to it throughout the greater 
part of its extent. 
Anterior or Palmar or Flexor Surface (facies volaris).-The anterior surface is 
concave for its upper three-fourths, and gives attachment to the Flexor longus 
pollicis muscle; it is broad and flat for its lower fourth, and gives attachment to 
the Pronator quadratus. A prominent ridge limits the attachment of the Pro- 
nator quadratus below, and between this and the inferior border is a triangular 
rough surface for the attachment of the anterior ligament of the wrist-joint. At 
the junction of the upper and middle third of this surface is the nutrient foramen 
(foramen nutricium), the opening of the nutrient canal (canalis nutricius), which 
is directed obliquely upward (proximally). 
Posterior or Dorsal or Extensor Surface (facies dorsalis).-The posterior surface 
is rounded, convex, and smooth in the upper third of its extent, and covered by 
the Supinator brevis muscle. Its middle third is broad, slightly concave, and gives 
attachment to the Extensor ossis metacarpi pollicis above, the Extensor brevis pol- 
licis below. Its lower third is broad, convex, and covered by the tendons of the 
muscles, which subsequently run in the grooves on the lower end of the bone. 
External Surface (facies lateralis).-The external surface is rounded and convex 
throughout its entire extent. Its upper third gives attachment to the Supinator 
brevis muscle. About its centre is seen a rough ridge, for the insertion of the Pro- 
nator radii teres muscle. Its lower part is narrow, and covered by the tendons 
of the Extensor ossis metacarpi pollicis and Extensor brevis pollicis muscles. 
Lower Extremity.-The lower extremity of the radius is large, of quadri- 
lateral form, and provided with two articular surfaces-one at the extremity, for 
articulation with the carpus, and one at the inner side of the bone, for articulation 
with the ulna. The carpal articular surface (facies articularis carpea) is of tri- 
angular form, concave, smooth, and divided by a slight antero-posterior ridge 
into two parts. Of these, the external is of a triangular form, and articulates with 
the scaphoid bone; the inner is quadrilateral and articulates with the semilunar 
bone. The articular surface for the head of the ulna is called the sigmoid cavity 
of the radius (incisura ulnaris)-, it is narrow, concave, smooth, and articulates 
with the head of the ulna. The circumference of this end of the bone presents 
three surfaces-an anterior, external, and posterior. The anterior surface, rough 
and irregular, affords attachment to the anterior ligament of the wrist-joint. The 
external surface is prolonged obliquely downward into a strong, conical projec- 
tion, the styloid process (processus styloideus), which gives attachment by its base 
to the tendon of the Supinator longus, and by its apex to the external lateral liga- 
ment of the wrist-joint. The outer surface of this process is marked by a flat 
groove, which runs obliquely downward and forward, and gives passage to the 
tendons of the Extensor ossis metacarpi pollicis and the Extensor brevis pollicis. 
The posterior surface is convex, affords attachment to the posterior ligament of 
the wrist, and is marked by three grooves. Proceeding from without inward, the 
first groove is broad but shallow, and subdivided into two by a slightly elevated 
ridge: the outer of these two transmits the tendon of the Extensor carpi radialis 192 
THE SKELETON 
longior, the inner the tendon of the Extensor carpi radialis brevior. The second, 
which is near the centre of the bone, is a deep but narrow groove, bounded on its 
outer side by a sharply-defined ridge; it is directed obliquely from above, down- 
ward and outward, and transmits the tendon of the Extensor longus pollicis. 
The third, lying most internally, is a broad groove, for the passage of the tendons 
of the Extensor indicis and Extensor communis digitorum. 
Structure.-Similar to that of the other long bones. 
Development (Fig. 136).-By three centres: one for the shaft and one for each 
extremity. That for the shaft makes its appearance near the centre of the bone, 
about the eighth week of foetal life. About 
the end of the second year ossification com- 
mences in the lower epiphysis, and about the 
fifth year in the upper end At the age of 
seventeen or eighteen the upper epiphysis be- 
comes joined to the shaft, the lower epiphysis 
becoming united about the twentieth year. 
Articulation.-With four bones: the humerus, 
ulna, scaphoid, and semilunar. 
Attachment of Muscles.-To nine: to the 
tuberosity, the Biceps, to the oblique ridge, the 
Supinator brevis, Flexor sublimis digitorum, 
and Flexor longus pollicis: to the shaft (its 
anterior surface), the Flexor longus pollicis 
and Pronator quadratus; (its posterior surface), 
the Extensor ossis metacarpi pollicis and Exten- 
sor brevis pollicis; (its outer surface), the Pro- 
nator radii teres; and to the styloid process, 
the Supinator longus. 
Appears at 
5th year. ' 
Head. 
Unites with shaft 
about puberty 
Appears at 
2d year. 
Surface Form.-Just below and a little in front of 
the posterior surface of the external condyle a part of 
the head of the radius may be felt, covered by the 
orbicular and external lateral ligaments. There is in 
this situation a little dimple in the skin, which is most 
visible when the arm is extended, and w'hich marks the 
position of the head of the bone. If the finger is placed on this dimple and the forearm pro- 
nated and supinated, the head of the bone will be distinctly perceived rotating in the lesser 
sigmoid cavity. The upper half of the shaft of the radius cannot be felt, as it is surrounded by 
the fleshy bellies of the muscles arising from the external condyle. The lower half of the shaft 
can be readily examined, though covered by tendons and muscles and not strictly subcutaneous. 
If traced downward, the shaft will be felt to terminate in a lozenge-shaped, convex surface 
on the outer side of the base of the styloid process. This is the only subcutaneous part of the 
bone, and from its lower extremity the apex of the styloid process will be felt bending inward 
toward the wrist. About the middle of the posterior aspect of the lower extremity of the bone 
is a well-marked ridge, best perceived when the hand is slightly flexed on the wrist. It forms 
the outer boundary of the oblique groove on the posterior surface of the bone, through which 
the tendon of the Extensor longus pollicis runs, and serves to keep that tendon in place. 
Surgical Anatomy of the Radius and Ulna. -The two bones of the forearm are more often 
broken together than is either the radius or ulna separately. It is therefore convenient to consider 
fractures of both bones in the first instance, and subsequently to mention the principal fractures 
which take place in each bone individually. These fractures may be produced by either direct 
or indirect violence, though more commonly by direct violence. When indirect force is applied 
to the forearm the radius generally alone gives way, though both bones may suffer. The 
fracture from indirect force generally takes place somewhere about the middle of the bones; 
fracture from direct violence may occur at any part, more often, howrever, in the lower half of 
the bone. The fracture is usually transverse, but may be more or less oblique. A point of 
interest in connection with these fractures is the tendency that there is for the two bones to unite 
across the interosseous membrane; the limb should therefore be put up in a position midway 
between supination and pronation, which is not only the most comfortable position, but also sep- 
arates the bones most widely from each other, and therefore diminishes the risk of the bones 
Unites with shaft 
about 20th year. 
Fig. 136.-Plan of the development of the 
radius. By three centres. 
Lower extremity. THE CARPUS 
193 
becoming united across the interosseous membrane. The splints, anterior and posterior, which 
are applied in these cases should be rather wider than the limb, so as to prevent any lateral 
pressure on the bones. In these cases there is a greater liability to gangrene from the pressure 
of the splints than in other parts of the body. This is no doubt due principally to two causes: 
(1) the flexion of the forearm compressing to a certain extent the brachial artery and retarding 
the flow of blood to the limb; and (2) the superficial position of the two main arteries of the 
forearm in a part of their course, and their liability to be compressed by the splints. The special 
fractures of the ulna are-(1) Fracture of the olecranon. This may be caused by direct violence, 
falls on the elbow, with the forearm flexed, or by muscular action by the sudden contraction of 
the triceps. The most common place for the fracture to occur is at the constricted portion 
where the olecranon joins the shaft of the bone, and the fracture may be either transverse or 
oblique; but any part may be broken, even a thin shell may be torn off. Fractures from direct 
violence are occasionally comminuted. The displacement is sometimes very slight, owing to the 
fibrous structures around the process not being torn. (2) Fracture of the coronoid process some- 
times occurs as a complication of dislocation backward of the bones of the forearm, but it is 
doubtful if it ever occurs as an uncomplicated injury. (3) Fractures of the shaft of the ulna 
may occur at any part, but usually takes place at the middle of the bone or a little below it. 
They are almost always the result of direct violence. (4) The styloid process may be knocked 
off by direct violence. Fractures of the radius consist of-(1) Fracture of the head of the bone; 
this generally occurs in conjunction with some other lesion, but may occur as an uncomplicated 
injury. (2) Fracture of the neck may also take place, but is generally complicated with other 
injury. (3) Fractures of the shaft of the radius are very common, and may take place at any 
part of the bone. They may take place from either direct or indirect violence. In fractures of the 
upper third of the shaft of the bone, that is to say, above the insertion of the Pronator radii teres, 
the displacement is very great. The upper fragment is strongly supinated by the Biceps and Supi- 
nator brevis, and flexed by the Biceps; while the lower fragment is pronated and drawn toward 
the ulna by the two pronators. If such a fracture is put up in the ordinary position, midway 
between supination and pronation, the fracture will unite with the upper fragment in a position 
of supination, and the lower one in the mid-position, and thus considerable impairment of the 
movements of the hand will result. The limb should be put up with the forearm supinated. (4) 
The most important fracture of the radius is that of the lower end (Colles's fracture}. The 
fracture is transverse, and generally takes place about an inch from the lower extremity. It is 
caused by falls on the palm of the hand, and is an injury of advanced life, occurring more fre- 
quently in the female than the male. In consequence of the manner in which the fracture is 
caused, the upper fragment becomes driven into the lower, and impaction is the result; or else 
the lower fragment becomes split up into two or more pieces, so that no fixation occurs. Sepa- 
ration of the lower epiphysis of the radius may take place in the young. This injury and Colles's 
fracture may be distinguished from other injuries in this neighborhood-especially dislocation, 
with which it is liable to be confounded-by observing the relative positions of the styloid 
processes of the ulna and radius. In the natural condition of parts, with the arm hanging by the 
side, the styloid process of the radius is on a lower level than that of the ulna; that is to say, 
nearer the ground. After fracture or separation of the epiphysis this process is on the same or 
a higher level than that of the ulna, whereas it would be unaltered in position in dislocation. 
THE HAND. 
The skeleton of the hand is subdivided into three segments-the carpus or wrist 
bones; the metacarpus or bones of the palm; and the phalanges or bones of the digits. 
The Carpus (Ossa Carpi) (Figs. 137, 138). 
The bones of the carpus (xao~o', the wrist), eight in number, are arranged 
in two rows. Those of the upper row, enumerated from the radial to the ulnar 
side, are the scaphoid, semilunar, cuneiform, and pisiform; those of the lower 
row, enumerated in the same order, are the trapezium, trapezoid, os magnum, 
and unciform. 
Common Characters of the Carpal Bones.-Each bone (excepting the pisiform) 
presents six surfaces. Of these the anterior, palmar, or volar, and the posterior or 
dorsal are rough for ligamentous attachment, the dorsal surface being the broader, 
except in the scaphoid and semilunar. The superior or proximal and inferior or 
distal are articular, the superior generally convex, the inferior concave; and the THE SKELETON 
194 
internal and external are also articular when in contact with contiguous bones, 
otherwise rough and tubercular. The structure in all is similar, consisting of 
Carpus. 
EXTENSOR CARPI 
RADIALIS LONQIOR. 
EXTENSOR CARPI 
ULNARIS. 
EXTENSOR CARPI 
RADIALIS BREVIOR. 
Metacarpus. 
EXTENSOR BREVIS 
POLLICIS. 
EXTENSOR LONQUS 
POLLIClS. 
Phalanges. 
1st Row. 
EXTENSOR 
DIGITORUM 
COMMUNIS 
and 
EXTENSOR 
MINIMI 
DIGITI. 
2nd Row. 
EXTENSOR DIGITORUM 
communis and < 
EXTENSOR INDICIS. 
EXTENSOR 
DIGITORUM, 
COMMUNIS. 
J 3rd Row 
EXTENSOR 
DIGITORUM^ 
COMMUNIS. 
Fig. 137.-Bones of the left hand. Dorsal surface. 
cancellous tissue enclosed in a layer of compact bone. Each bone is also developed 
from a single centre of ossification. THE CARPUS 
195 
Bones of the Upper Row. 
Scaphoid or Navicular Bone (os naviculare manus, the boat-like bone) (Fig. 
139).-The scaphoid (axdip^, a boat, eldo^, like) is the largest bone of the first 
Carpus. 
Groove for tendon of 
FLEXOR CARPI RADIALIS 
FLEXOR CARPI ULNARIS. 
FLEXOR OSSIS 
^METACARPI POLLICIS. 
FLEXOR BREVIS MINIMI DIGITI.. 
•FLEXOR BREVIS POLL. 
EXTEN. OS. METACARP. POLL. 
FLEXOR OSSIS METACARPI, 
MINIMI DIGITI. 
EXTENSOR OSSIS 
METACARPI POLLICIS. 
Metacarpus. 
ADDUCTOR 
TRANSVERS 
and 
OBLIQUUS 
POLLICIS. 
Sesamoid 
bones. 
FLEX. BREVIS 
and 
ABDUCTOR 
MINIMI DIGTI. 
ABDUCTOR 
" POLLICIS. 
FLEXOR 
BREVIS POLLICIS. 
FLEXUS 
LONQUS- 
POLLICIS 
FLEXOR 
DIGITORUM 
SUBLIMIS. 
FLEXOR 
DIGITORUM 
PROFUNDUS. 
, FLEXOR 
DIGITORUM 
8UBLIMIS. 
FLEXOR 
DIQITORUM 
PROFUNDUS. 
Fig. 138.-Bones of the left hand. Palmar surface. 
row. It has received its name from its fancied resemblance to a boat, being 
broad at one end and narrowed like a prow at the opposite. It is situated at 196 
THE SKELETON 
the upper and outer part of the carpus, its long axis being from above down- 
ward, outward, and forward. 
Surfaces.-The superior surface is convex, smooth, of triangular shape, and 
articulates with the lower end of the radius. The inferior surface, directed 
Tuberosity. 
For radius. 
For semilunar. 
For trapezium.' 
For os magnum. 
For trapezoid. 
Fig. 139.-The left scaphoid. 
downward, outward, and backward, is smooth, convex, also triangular, and 
divided by a slight ridge into two parts, the external of which articulates with 
the trapezium, the inner with the trapezoid. The posterior or dorsal surface 
presents a narrow, rough groove which runs the entire length of the bone and 
serves for the attachment of ligaments. The anterior or palmar surface is concave 
above, and elevated at its lower and outer part into a prominent rounded tuber- 
osity (tuberculum ossis navicularis), which projects forward from the front of the 
carpus and gives attachment to the anterior annular ligament of the wrist and 
sometimes a few fibres of the Abductor pollicis. The external surface is rough 
and narrow, and gives attachment to the external lateral ligament of the wrist. 
The internal surface presents two articular facets: of these, the superior or smaller 
one is flattened, of semilunar form, and articulates with the semilunar; the inferior 
or larger is concave, forming, with the semilunar bone, a concavity for the head 
of the os magnum. 
To ascertain to which side the bone belongs, hold it with the superior or radial 
convex, articular surface upward, and the posterior surface-i. e., the narrow, 
non-articular, grooved surface-toward you. The tubercle on the outer surface 
points to the side to which the bone belongs.1 
Articulations.-With five bones: the radius above, trapezium and trapezoid 
below, os magnum and semilunar internally. 
Attachment of Muscles.-Occasionally a few fibres of the Abductor pollicis. 
Semilunar (os lunatum) (Fig. 140).-The semilunar (semi, half; luna, moon) 
bone may be distinguished by its deep concavity and crescentic outline. It is 
For cuneiform. 
For radius. 
For 
scaphoid. 
For unciform. 
For os magnum. 
Fig. 140.-The left semilunar. 
situated in the centre of the upper row of the carpus, between the scaphoid and 
cuneiform. 
Surfaces.-The superior surface, convex, smooth, and bounded by four edges, 
articulates with the radius. The inferior surface is deeply concave, and of greater 
1 In these directions each bone is supposed to be placed in its natural position-that is, such a position as it 
would occupy when the arm is hanging by the side, the forearm in a position of supination, the thumb being 
directed outward, and the palm of the hand looking forward. THE CARPUS 
197 
extent from before backward than transversely: it articulates with the head of the 
os magnum and by a long, narrow facet (separated by a ridge from the general 
surface) with the unciform bone. The anterior or palmar and posterior or dorsal 
surfaces are rough, for the attachment of ligaments, the former being the broader 
and of a somewhat rounded form. The external surface presents a narrow, flat- 
tened, semilunar facet for articulation with the scaphoid. The internal surface 
is marked by a smooth, quadrilateral facet, for articulation with the cuneiform. 
Hold it with the convex articular surface for the radius upward, and the nar- 
rowest non-articular surface toward you. The semilunar facet for the scaphoid 
will be on the side to which the bone belongs. 
Articulations.-With five bones: the radius above, os magnum and unciform 
below, scaphoid and cuneiform on either side. 
Cuneiform (os triquetrum, the wedge-shaped bone) (Fig. 141).-The cuneiform 
(cuneus, a wedge; forma, likeness) may be distinguished by its pyramidal 
shape, and by its having an oval, isolated facet for articu- 
lation with the pisiform bone. It is situated at the upper 
and inner side of the carpus. 
Surfaces.-The superior surface presents an internal, rough, 
non-articular portion, and an external or articular portion, 
which is convex, smooth, and articulates with the triangular 
interarticular fibro-cartilage of the wrist. The inferior sur- 
face, directed outward, is concave, sinuously curved, and 
smooth for articulation with the unciform. The posterior 
or dorsal surface is rough, for the attachment of ligaments. The anterior or 
palmar surface presents, at its inner side, an oval facet, for articulation with 
the pisiform; and is rough externally, for ligamentous attachment. The exter- 
nal surface, the base of the pyramid, is marked by a flat, quadrilateral, smooth 
facet, for articulation with the semilunar. The internal surface, the summit of 
the pyramid, is pointed and roughened, for the attachment of the internal lateral 
ligament of the wrist. 
Hold the bone with the surface supporting the pisiform facet away from you, 
and the concavo-convex surface for the unciform downward. The base of the 
wedge (i. e., the broad end of the bone) will be on the side to which it belongs. 
Articulations.-With three bones: the semilunar externally, the pisiform in 
front, the unciform below; and with the triangular, interarticular fibro-cartilage 
which separates it from the lower end of the ulna. 
Pisiform (os pisiforme) (Fig. 142).-The pisiform (pisum, a pea; forma, like- 
ness) may be known by its small size and by its presenting a single articular 
facet. It is situated on a plane anterior to the other bones of 
the carpus; it is spheroidal in form, with its long diameter 
directed vertically. 
Surfaces.-Its posterior surface is a smooth, oval facet, for 
articulation with the cuneiform. This facet approaches the 
superior, but not the inferior border of the bone. The anterior 
or palmar surface is rounded and rough, and gives attachment 
to the anterior annular ligament and to the Flexor carpi 
ulnaris and Abductor minimi digiti muscles. The outer and inner surfaces are 
also rough, the former being concave, the latter usually convex. 
Hold the bone with the posterior surface-that which presents the articular 
facet-toward you, in such a manner that the faceted portion of the surface is 
uppermost. The outer, concave surface will point to the side to which it belongs. 
Articulations.-With one bone, the cuneiform. 
Attachment of Muscles.-To two: the Flexor carpi ulnaris and Abductor 
minimi digiti; and to the anterior annular ligament. 
For pisiform 
For semilunar. 
Fig. 141.-The left cunei- 
form. 
For unciform. 
For 
cuneiform. 
Fig. 142.-The left 
pisiform. 198 
THE SKELETON 
Bones of the Lower Row. 
Trapezium (os multangulum majus) (Fig. 143).-The trapezium (Tpdne'a, a 
table) is of very irregular form. It may be distinguished by a deep groove, for 
For trapezoid. 
Groove. 
Ridge. 
For scaphoid. 
For trapezoid. 
For 2d 
metacarpal. 
For 1st metacarpal. 
Fig. 143.-The left trapezium. 
For 3d metacarpal. 
the tendon of the Flexor carpi radialis muscle. It is situated at the external and 
inferior part of the carpus between the scaphoid and first metacarpal bone. 
Surfaces.-The superior surface, concave and smooth, is directed upward and 
inward, and articulates with the scaphoid. The inferior surface, directed down- 
ward and inward, is oval, concave from side to side, convex from before backward, 
so as to form a saddle-shaped surface, for articulation with the base of the first 
metacarpal bone. The anterior or palmar surface is narrow and rough. At its 
upper part is a deep groove running from above obliquely downward and inward; 
it transmits the tendon of the Flexor carpi radialis, and is bounded externally 
by a prominent ridge, the oblique ridge of the trapezium (tuberculum ossis mul- 
tanguli major is). This surface gives attachment to the Abductor pollicis, Flexor 
ossis metacarpi pollicis, and Flexor brevis pollicis muscles, and the anterior 
annular ligament. The posterior or dorsal surface is rough. The external sur- 
face is also broad and rough, for the attachment of ligaments. The internal 
surface presents two articular facets: the upper one, large and concave, articu- 
lates with the trapezoid; the lower one, small and oval, with the base of the 
second metacarpal bone. 
Hold the bone with the saddle-shaped surface downward and the grooved 
surface away from you. The prominent, rough, non-articular surface points to 
the side to which the bone belongs. 
Articulations.-With four bones: the scaphoid above, the trapezoid and second 
metacarpal bones internally, the first metacarpal below. 
Attachment of Muscles.-Abductor pollicis, Flexor ossis metacarpi pollicis, and 
part of the Flexor brevis pollicis. 
Trapezoid (os multangulum minus') (Fig. 144).-The trapezoid is the smallest 
bone in the second row. It may be known by its wedge-shaped form, the broad 
Anterior surface. 
For scaphoid. 
For trapezium. 
For os magnum. 
Post, surface. 
For 3d metacarpal. 
Fig. 144.-The left trapezoid. 
end of the wedge forming the dorsal, the narrow end the palmar, surface, and by 
its having four articular surfaces touching each other and separated by sharp 
edges. 
Surfaces.-The superior surface, quadrilateral in form, smooth, and slightly con- 
cave, articulates with the scaphoid. The inferior surface articulates with the upper THE CARPUS 
199 
end of the second metacarpal bone; it is convex from side to side, concave from before 
backward, and subdivided by an elevated ridge into two unequal lateral facets. 
The posterior or dorsal and anterior or palmar surfaces are rough, for the attach- 
ment of ligaments, the former being the larger of the two. The external surface, 
convex and smooth, articulates with the trapezium. The internal surface is con- 
cave and smooth in front, for articulation with the os magnum; rough behind, 
for the attachment of an interosseous ligament. 
Hold the bone with the larger, non-articular surface toward you, and the 
smooth, quadrilateral articular surface upward. The convex articular surface 
will point to the side to which the bone belongs.1 
Articulations.-With four bones: the scaphoid above, second metacarpal bone 
below, trapezium externally, os magnum internally. 
Os Magnum (os capitatum) (Fig. 145).-The os magnum is the largest bone 
of the carpus, and occupies the centre of the wrist. It presents, above, a rounded 
For scaphoid.. 
For semilunar. 
For semilunar. 
For 
trapezoid. 
For unciform. 
For 2d 
metacarpal. 
For 3d For 4th metacarpal, 
metacarpal. 
For 4th 
metacarpal. 
Fig. 145.-The left os magnum. 
Ant. surface. 
portion or head, which is received into the concavity formed by the scaphoid and 
semilunar bones; a constricted portion or neck; and, below, the body. 
Surfaces.-The superior surface is rounded, smooth, and articulates with the semi- 
lunar. The inferior surface is divided by two ridges into three facets for articulation 
with the second, third, and fourth metacarpal bones, that for the third (the middle 
facet) being the largest of the three. The posterior or dorsal surface is broad and 
rough; the anterior or palmar, narrow, rounded, and also rough, for the attachment 
of ligaments and a part of the Adductor obliquus pollicis. The external surface 
articulates with the trapezoid by a small facet at its anterior inferior angle, behind 
which is a rough depression for the attachment of an interosseous ligament. 
Above this is a deep and rough groove, which forms part of the neck and serves 
for the attachment of ligaments, bounded superiorly by a smooth, convex stirface, 
for articulation with the scaphoid. The internal surface articulates with the unci- 
form by a smooth, concave, oblong facet which occupies its posterior and superior 
parts, and is rough in front, for the attachment of an interosseous ligament. 
Hold the bone with the broader, non-articular surface toward you, and the 
head upward. The small, articular facet at the anterior inferior angle of the 
external surface will point to the side to which the bone belongs. 
Articulations.-With seven bones: the scaphoid and semilunar above; the 
second, third, and fourth metacarpal below; the trapezoid on the radial side; and 
the unciform on the ulnar side. 
Attachment of Muscles.-Part of the Adductor obliquus pollicis. 
Unciform (os hamatum) (Fig. 146).-The unciform or hook bone (uncus, a hook; 
forma, likeness) may be readily distinguished by its wedge-shaped form and the 
hook-like process that projects from its palmar surface. It is situated at the inner 
1 Occasionally in a badly marked bone there is some difficulty in ascertaining to which side the bone belongs; 
the following method will sometimes be found useful : Hold the bone with its broader, non-articular surface 
upward, so that its sloping border is directed toward you. The border will slope to the side to which the bone 
belongs. THE SKELETON 
200 
and lower angle of the carpus, with its base downward, resting on the two inner 
metacarpal bones, and its apex directed upward and outward. 
Surfaces.-The superior surface, the apex of the wedge, is narrow, convex, 
smooth, and articulates with the semilunar. The inferior surface articulates with 
For semilunar. 
For os magnum.- 
For cuneiform. 
For fourth meta-^ 
tarsal. 
Unciform process. 
For fifth 
metatarsal. 
Fig. 146.-The left unciform. 
the fourth and fifth metacarpal bones, the concave surface for each being sepa- 
rated by a ridge which runs from before backward. The posterior or dorsal 
surface is triangular and rough, for ligamentous attachment. The anterior or 
palmar surface presents, at its lower and inner side, a curved, hook-like pro- 
cess of bone, the unciform process (hamulus ossis hamati), directed from the 
palmar surface forward and outward. It gives attachment by its apex to the 
annular ligament and Flexor carpi ulnaris; by its inner surface to the Flexor brevis 
minimi digiti and the Opponens minimi digiti; and is grooved on its outer 
side, for the passage of the Flexor tendons into the palm of the hand. This is 
one of the four eminences on the front of the carpus to which the anterior 
annular ligament is attached, the others being the pisiform internally, the oblique 
ridge of the trapezium and the tuberosity of the scaphoid externally. The internal 
surface articulates with the cuneiform by an oblong facet cut obliquely from above, 
downward and inward. The external surface articulates with the os magnum by 
its upper and posterior part, the remaining portion being rough, for the attach- 
ment of ligaments. 
Hold the bone with the hooked process away from you, and the articular sur- 
face, divided into two parts, for the metacarpal bones, downward The concavity 
of the process will be on the side to which the bone belongs. 
Articulations.-With five bones: the semilunar above, the fourth and fifth 
metacarpal below, the cuneiform internally, the os magnum externally. 
Attachment of Muscles.-To three: the Flexor brevis minimi digiti, the Opponens- 
minimi digiti, the Flexor carpi ulnaris. 
The Metacarpus (Ossa Metacarpalia) (Figs. 137, 138). 
The metacarpal bones are five in number, and they are numbered from 1 to 
5 inclusive, the first being the metacarpal bone of the thumb, the fifth the 
metacarpal bone of the index finger. They are long, cylindrical bones, pre- 
senting for examination a shaft and two extremities. 
Common Characters of the Metacarpal Bones. The Shaft (corpus).-The 
shaft is prismoid in form and curved longitudinally, so as to be convex in the 
longitudinal direction behind, concave in front. It presents three surfaces: 
two lateral and one posterior. The two lateral surfaces constitute the palmar or 
volar surface. The lateral surfaces are concave, for the attachment of the Inter- 
ossei muscles, and separated from one another by a prominent anterior ridge. 
The posterior or dorsal surface presents in its distal half a smooth, triangular, flat- 
tened area which is covered, in the recent state, by the tendons of the Extensor 
muscles. This triangular surface is bounded by two lines, which commence in THE METACARPUS 
201 
small tubercles situated on the dorsal aspect on either side of the digital extremity, 
and, running backward, converge to meet together a little behind the centre of 
the bone and form a ridge which runs along the rest of the dorsal surface to the 
carpal extremity. This ridge separates two lateral, sloping surfaces for the 
attachment of the Dorsal interossei muscles.1 To the tubercles on the digital 
extremities are attached the lateral ligaments of the metacarpo-phalangeal joints. 
On the palmar surface of each metacarpal bone is a nutrient foramen (foramen 
nutricium), which opens into a nutrient canal (canalis nutricius). In the thumb 
metacarpal the direction of this foramen is toward the periphery (distally). In 
each of the other metacarpals it is from the periphery (proximally). 
Carpal or Proximal Extremity or Base (basis).-The carpal extremity, or base, 
is of a cuboidal form, and broader behind than in front; it articulates above 
with the carpus, and on each side with the adjoining metacarpal bones; its dorsal 
and palmar surfaces are rough, for the attachment of tendons and ligaments. 
Digital or Distal Extremity or Head (capitulum).-The digital extremity, or head, 
presents an oblong surface, markedly convex from before backward, less so from 
side to side, and flattened laterally; it articulates with the proximal phalanx; it is 
broader and extends farther forward on the palmar than on the dorsal aspect. It 
is longer in the antero-posterior than in the transverse diameter. On either side of 
the head is a tubercle for the attachment of the lateral ligament of the metacarpo- 
phalangeal joint. The posterior surface, broad and flat, supports the Extensor 
tendons; the anterior surface is grooved in the middle line for the passage of the 
Flexor tendons, and marked on each side by an articular eminence continuous with 
the terminal articular surface. The metacarpal spaces (spatia interossea metacarpi) 
are the intervals between the metacarpal bones. They are occupied by the 
Interossei muscles. The broadest space is between the metacarpal bones of the 
thumb and index finger. 
Peculiar Characters of the Metacarpal Bones.-The Metacarpal Bone of the 
Thumb (os metacarpale I) (Fig. 147) is shorter and wider than the rest, diverges to a 
greater degree from the carpus, and its palmar sur- 
face is directed inward toward the palm. The shaft 
is flattened and broad on its dorsal aspect, and 
does not present the ridge which is found on the 
other metacarpal bones; it is concave from above 
downward, on its palmar surface. The carpal 
extremity, or base, presents a concavo-convex sur- 
face, for articulation with the trapezium; it has 
no lateral facets, but presents externally a tubercle 
for the insertion of the Extensor ossis metacarpi 
pollicis. The digital extremity is less convex than 
that of the other metacarpal bones, broader from 
side to side than from before backward. It pre- 
sents on its palmar aspect two distinct articular 
eminences for the two sesamoid bones in the ten- 
dons of the Flexor brevis pollicis, the outer one 
being the larger of the two. 
The side to which this bone belongs may be known by holding it in the position 
it occupies in the hand, with the carpal extremity upward and the dorsal surface 
backward; the tubercle for the Extensor ossis metacarpi pollicis will point to the 
side to which it belongs. 
Attachment of Muscles.-To four: the Flexor ossis metacarpi pollicis, the Extensor 
ossis metacarpi pollicis, the Flexor brevis pollicis, and the First dorsal interosseous. 
Tubercle. 
For trapezium. 
For trapezium. 
Fig. 147.-The first metacarpal. (Left.) 
1 By these sloping surfaces the metacarpal bones of the hand may be at once differentiated from the meta- 
tarsal bone of the foot. 202 
THE SKELETON 
The Metacarpal Bone of the Index Finger (os metacarpale II) (Fig. 148) is the 
longest and its base the largest of the other four. Its carpal extremity is prolonged 
upward and inward, forming a prominent ridge. The dorsal and palmar surfaces 
of this extremity are rough, for the attachment of tendons and ligaments. It pre- 
sents four articular facets: three on the upper aspect of the base: the middle one of 
the three is the largest, concave from side to side, convex from before backward, for 
articulation with the trapezoid; the external one is a small, flat, oval facet, for 
articulation with the trapezium; the internal one on the summit of the ridge is long 
and narrow, for articulation with the os magnum. The fourth facet is on the inner 
or ulnar side of the extremity of the bone, and is for articulation with the third 
metacarpal bone. 
The side to which this bone belongs is indicated by the absence of the lateral 
facet on the outer (radial) side of its base, so that if the bone is placed with the 
base toward the student and the palmar surface upward, the side on which there 
is no lateral facet will be that to which it belongs. 
For trapezoid. 
For trapezium. 
For os magnum. 
For third metacarpal. 
Styloid 
process. 
For second 
metacarpal. 
For os magnum. 
For fourth 
metacarpal. 
Fig. 148.-The second metacarpal. (Left.) 
Fig. 149.-The third metacarpal. (Left.) 
Attachment of Muscles.-To six: Flexor carpi radialis, Extensor carpi radialis 
longior, Adductor obliquus pollicis, First and Second dorsal interosseous, and 
First palmar interosseous. 
The Metacarpal Bone of the Middle Finger (os metacarpale III) (Fig. 149) is a 
little smaller than the preceding: it presents a pyramidal eminence, the styloid 
process (processus styloideus), on the radial side of its base (dorsal aspect), which 
extends upward behind the os magnum; immediately below this, on the dorsal 
aspect, is a rough surface for the attachment of the Extensor carpi radialis brevior. 
The carpal, articular facet is concave behind, flat in front, and articulates with the 
os magnum. On the radial side is a smooth, concave facet, for articulation with 
the second metacarpal bone, and on the ulnar side two small, oval facets, for articu- 
lation with the fourth metacarpal. 
The side to which this bone belongs is easily recognized by the styloid process 
on the radial side of its base. With the palmar surface uppermost and the base 
toward the student, this process points toward the side to which the bone belongs. THE METACARPUS 
203 
Attachment of Muscles.-To six: Extensor carpi radialis brevior, Flexor carpi 
radialis, Adductor transversus pollicis, Adductor obliquus pollicis, and Second and 
Third dorsal interosseous. 
The Metacarpal Bone of the Ring Finger (os metacarpale IV) (Fig. 150) is shorter 
and smaller than the preceding, and its base small and quadrilateral; the carpal 
surface of the base presenting two facets, a large one externally, for articulation 
with the unciform, and a small one internally, for the os magnum. On the radial 
side are two oval facets, for articulation with the third metacarpal bone; and on 
the ulnar side a single concave facet, for the fifth metacarpal. 
If this bone is placed with the base toward the student and the palmar surface 
upward, the radial side of the base, which has two facets for articulation with the 
third metacarpal bone, will be on the side to which it belongs. If, as sometimes 
happens in badly marked bones, one of these facets is indistinguishable, the side 
may be known by selecting the surface on which the larger articular facet is present. 
This facet is for the fifth metacarpal bone, and would therefore be situated on the 
ulnar side-that is, the one to which the bone does not belong. 
For third 
metacarpal. 
For on 
magnum. 
For fift h meta- 
carpal 
For fourth 
metacarpal. 
For cuneiform. 
Fig. 150.-The fourth metacarpal. (Left.) 
For unciform. 
Fig. 151.-The fifth metacarpal. (Left.) 
Attachment of Muscles.-To three: the Third and Fourth dorsal and Second 
palmar interosseous. 
The Metacarpal Bone of the Little Finger (os metacarpale V) (Fig. 151) presents on 
its base one facet, which is concavo-convex, and which articulates with the unciform 
bone, and one lateral, articular facet, which articulates with the fourth metacarpal 
bone. On its ulnar side is a prominent tubercle, for the insertion of the tendon of 
the Extensor carpi ulnaris. The dorsal surface of the shaft is marked by an oblique 
ridge which extends from near the ulnar side of the upper extremity to the radial 
side of the lower. The outer division of this surface serves for the attachment of 
the Fourth dorsal interosseous muscle; the inner division is smooth and covered 
by the Extensor tendons of the little finger. 
If this bone is placed with its base toward the student and its palmar surface 
upward, the side of the head which has a lateral facet will be that to which the 
bone belongs. 
Attachment of Muscles.-To five: the Extensor carpi ulnaris, Flexor carpi 
ulnaris, Flexor ossis metacarpi minimi digiti, Fourth dorsal, and Third palmar 
interosseous. THE SKELETON 
204 
Articulations.-Besides the phalangeal articulations, the first metacarpal bone 
articulates with the trapezium; the second with the trapezium, trapezoid, os 
magnum, and third metacarpal bones; the third with the os magnum and second 
and fourth metacarpal bones; the fourth with the os magnum, unciform, and 
third and fifth metacarpal bones; and the fifth with the unciform and fourth 
metacarpal. 
The first has no lateral facets on its carpal extremity; the second has no lateral 
facet on its radial side, but one on its ulnar side; the third has one on its radial 
and two on its ulnar side; the fourth has two on its radial and one on its ulnar 
side; and the fifth has only one on its radial side. 
The Phalanges of the Hand (Phalanges Digitorum Manus). 
The phalanges (internodia) are the bones of the fingers; they are fourteen in 
number, three for each finger, and two for the thumb. In numbering them the 
proximal bone is designated as the first phalanx (phalanx 1). They are long bones, 
and present for examination a shaft and two extremities. The shaft (corpus 
phalangis) tapers from above downward, is convex posteriorly, concave in front 
from above downward, flat from side to side, and marked laterally by rough 
ridges, which give attachment to the fibrous sheaths of the Flexor tendons. A 
nutrient foramen on the palmar surface leads into a nutrient canal which runs 
toward the periphery (distalward). The metacarpal extremity or base (basis 
phalangis) of each phalanx in the first row presents an oval, concave, articular 
surface, broader from side to side than from before backward; and the same 
extremity in the other two rows, a double concavity, separated by a longitudinal 
median ridge, extending from before backward. The distal extremity of the first 
phalanx of the thumb and of the first and second phalanx of each of the fingers is 
smaller than the base, and terminates in two small, lateral condyles, separated 
by a slight groove (trochlea phalangis); the articular surface being prolonged far- 
ther forward on the palmar than on the dorsal surface, especially in the first row. 
The Ungual Phalanges (distal) are convex on their dorsal, flat on their palmar, 
surfaces; they are recognized by their small size and by a roughened, elevated 
surface of a horseshoe form on the palmar aspect of their ungual extremity 
(tuberositas unguicularis), which serves to support the sensitive pulp of the finger. 
Articulations.-The first row, with the metacarpal bones and the second row of 
phalanges; the second row, with the first and third; the third, with the second row. 
Attachment of Muscles.-To the base of the first phalanx of the thumb, five 
muscles: the Extensor brevis pollicis, Flexor brevis pollicis, Abductor pollicis, 
Adductor transversus and Obliquus pollicis. To the second phalanx, two: the 
Flexor longus pollicis and the Extensor longus pollicis. To the base of the first 
phalanx of the index finger, the First dorsal and the First palmar interosseous; to 
that of the middle finger, the Second and Third dorsal interosseous; to that of 
the ring finger, the Fourth dorsal and the Second palmar interosseous; and to that 
of the little finger, the Third palmar interosseous, the Flexor brevis minimi digiti, 
and Abductor minimi digiti. To the second phalanges, the Extensor sublimis digi- 
torum, Extensor communis digitorum, and, in addition, the Extensor indicis to 
the index finger, the Extensor minimi digiti to the little finger. To the third 
phalanges, the Flexor profundus digitorum and Extensor communis digitorum. 
Surface Form.-On the front of the wrist are two subcutaneous eminences, one on the 
radial side, the larger and flatter, due to the tuberosity of the scaphoid and the ridge on the 
trapezium; the other, on the ulnar side, caused by the pisiform bone. The tubercle of the 
scaphoid is to be felt just below and in front of the apex of the styloid process of the radius. It 
is best perceived by extending the hand on the forearm. Immediately below is to be felt 
another prominence, better marked than the tubercle; this is the ridge on the trapezium which 
gives attachment to some of the short muscles of the thumb. On the inner side of the front of DEVELOPMENT OF THE BONES OF THE HAND 
205 
the wrist the pisiform bone is to be felt, forming a small but prominent projection in this situa- 
tion. It is some distance below the styloid process of the ulna, and may be said to be just below 
the level of the styloid process of the radius. The rest of the front of the carpus is covered by 
tendons and the annular ligament, and entirely concealed, with the exception of the hooked 
process of the unciform, which can only be made out with difficulty. The back of the carpus is 
convex and covered by the Extensor tendons, so that none of the posterior surfaces of the bones 
are to be felt, with the exception of the cuneiform on the inner side. Below the carpus the 
dorsal surfaces of the metacarpal bones, except the fifth, are covered by tendons, and are scarcely 
visible except in very thin hands. The dorsal surface of the fifth is, however, subcutaneous 
throughout almost its whole length, and is plainly to be perceived and felt. In addition to this, 
slightly external to the middle line of the hand, is a prominence, frequently well marked, but 
occasionally indistinct, formed by the base of the metacarpal of the middle finger. The heads of 
the metacarpal bones are plainly to be felt and seen, rounded in contour and standing out in bold 
relief under the skin, when the fist is clenched. It should be borne in mind that when the fin- 
gers are flexed on the hand, the articular surfaces of the first phalanges glide off the heads of the 
metacarpal bones on to their anterior surfaces, so that the head of these bones form the prom- 
inence of the knuckles and receive the force of any blow which may be given. The head of the 
third metacarpal bone is the most prominent, and receives the greater part of the shock of the 
blow. This bone articulates with the os magnum, so that the concussion is carried through this 
bone to the scaphoid and semilunar, with which the head of the os magnum articulates, and by 
these bones is transferred to the radius, along which it may be carried to the capitellum of the 
humerus. The enlarged extremities of the phalanges are to be plainly felt: they form the 
joints of the fingers. When the digits are bent the proximal phalanges of the joints form 
prominences, which in the joint between the first and second phalanges is slightly hollowed, in 
accordance with the grooved shape of their articular surfaces, whilst at the last row the prom- 
inence is flattened and square-shaped. In the palm of the hand the four inner metacarpal bones 
are covered by muscles, tendons, and the palmar fascia, and no part of them but their heads 
is to be distinguished. With regard to the thumb, on the dorsal aspect the base of the meta- 
carpal bone forms a prominence below the styloid process of the radius; the shaft is to be felt, 
covered by tendons, terminating at its head in a flattened prominence, in front of which can be 
felt the sesamoid bones. 
Surgical Anatomy.-The carpal bones are not very liable to fracture, except from extreme 
violence, when the parts may be so comminuted as to necessitate amputation. Occasionally they 
are the seat of tuberculous disease. The metacarpal bones and the phalanges are not unfrequently 
broken by direct violence. The first metacarpal bone is the one most commonly fractured; 
then the second, the fourth, and the fifth, the third being the one least frequently broken. There 
are two diseases of the metacarpal bones and phalanges which require special mention on 
account of the frequency of their occurrence. One is tuberculous dactylitis, consisting in a 
deposit of tuberculous material in the medullary canal, expanding the bone, with subsequent 
caseation and resulting necrosis. The other is chondroma, which is perhaps more frequently 
found in connection with the metacarpal bones and phalanges than with any other bones. When 
chondromatous growth takes place there are usually multiple tumors, and they may spring 
either from the medullary canal or from the periosteum. 
Development of the Bones of the Hand. 
The Carpal Bones are each developed by a single centre. At birth they are 
all cartilaginous. Ossification proceeds in the following order (Fig. 152): In the 
os magnum and unciform an ossific point appears during the first year, the former 
preceding the latter; in the cuneiform, at the third year; in the trapezium and 
semilunar, at the fifth year, the former preceding the latter; in the scaphoid, at 
the sixth year; in the trapezoid, during the eighth year; and in the pisiform, about 
the twelfth year. 
Occasionally an additional bone, the os centrale, is found in the carpus, lying 
between the scaphoid, trapezoid, and os magnum. During the second month of 
foetal life it is represented by a small cartilaginous nodule, which, however, 
fuses with the cartilaginous scaphoid about the third month. Sometimes the 
styloid process of the third metacarpal is detached and forms an additional 
ossicle. 
The Metacarpal Bones are each developed by two centres: one for the shaft 
and one for the digital extremity for the four inner metacarpal bones; one for the 
shaft and one for the base for the metacarpal bone of the thumb, which in this THE SKELETON 
206 
respect resembles the phalanges.1 Ossification commences in the centre of the 
shaft about the eighth or ninth week, and gradually proceeds to either end of the 
bone: about the third year the digital extremities of the four inner metacarpal 
bones and the base of the first metacarpal begin to ossify, and they unite about 
the twentieth year. 
Carpus. 
One centre for each bone. 
All cartilaginous at birth. 
, Appears 3rd year. 
Unite 20th year. 
Metacarpus. 
Two centres for each bone: 
One for shaft, 
One for digital extremity, 
except first. 
.Appears 8th week. 
Appears 
'8th week. 
Phalanges. 
Two centres for each bone: 
One for shaft, 
One for metacarpal 
extremity. 
Unite 
20th year. 
\ Appears 3rd year. 
Appears Srd-^th 
year. 
Unite 18lhr-eotb 
year. 
1st Row. 
.Appears 8th week. 
■Appears Uh-5th year. 
2nd Row. 
Unite 18th-20th year. 
Appears 8th week. 
3rd Row. 
Appears Mh-5th year. 
Unite 18th-~0 year. 
■Appears 8th week. 
Fig. 152.-Plan of the development of the hand. 
The Phalanges are each developed by two centres; one for the shaft and one 
for the base. Ossification commences in the shaft, in all three rows, at about the 
eighth week, and gradually involves the whole of the bone excepting the upper 
extremity. Ossification of the base commences in the first row between the third 
and fourth years, and a year later in those of the second and third rows. The two 
centres become united, in each row, between the eighteenth and twentieth years. 
In the ungual phalanges the centre for the shaft appears at the distal extremity 
of the phalanx, instead of at the middle of the shaft, as is the case with the other 
phalanges. 
THE LOWER EXTREMITY. 
The bones of the lower extremity consist of those of the pelvic girdle, of the 
thigh, of the leg, and of the foot. 
1 Allan Thomson has demonstrated the fact that the first metacarpal bone is often developed from three 
centres; that is to say, there is a separate nucleus for the distal end, forming a distinct epiphysis, visible at the 
age of seven or eight years. He also states that there are traces of a proximal epiphysis in the second meta- 
carpal bone.-Journal of Anatomy, 1869. THE OS INNOMINATUM 
207 
THE PELVIC GIRDLE. 
The pelvic girdle consists of a single bone, the os innominatum, by which the 
thigh is connected to the trunk. 
The Os Innominatum, called also Os Coxae, Hip Bone, Haunch Bone, 
the Nameless Bone (Figs. 153, 154). 
The os innominatum (in, not; nomino, I name) is so called from bearing no 
resemblance to any known object. It is a large, irregularly shaped, flat bone, con- 
stricted in the centre and expanded above and below. With its fellow of the 
opposite side it forms the sides and anterior wall of the pelvic cavity. In young 
subjects it consists of three separate parts, which meet and form the large, cup- 
like cavity, the acetabulum, situated near the middle of the outer surface of the 
bone; and, although in the adult these have become united, it is usual to describe 
the bone as divisible into three portions-the ilium, the ischium, and the pubis. 
The ilium, so called from its supporting the flank (ilium or ileum, the flank), 
is the superior, broad, and expanded portion which runs upward from the 
acetabulum and forms the prominence of the hip. 
The ischium (ia^tov, the hip) is the inferior and strongest portion of the bone; 
it proceeds downward from the acetabulum, expands into a large tuberosity, and 
then, curving forward, forms, with the descending ramus of the os pubis, a large 
aperture, the obturator foramen. 
The os pubis is that portion which extends inward and downward from the 
acetabulum to articulate in the middle line with the bone of the opposite side: it 
forms the front of the pelvis, supports the external organs of generation, and has 
received its name from the skin over it being covered with hair (pubes). 
The Ilium (os ilium).-The lower or constricted part of the ilium is thick, 
though narrower than the expanded portion. It aids in the formation of the 
acetabulum and is called the body (corpus ossis ilium). The broad expanded 
portion of the ilium is thin in many places. It is called the ala (ala ossis ilium). 
The ilium presents for examination two surfaces, an external and an internal; a 
crest, and two borders, an anterior and a posterior. 
External Surface or Dorsum of the Ilium (Fig. 153).-The posterior part of this 
surface is directed backward and outward; its front part, downward and outward. 
It is smooth, convex in front, deeply concave behind; bounded above by the crest, 
below by the upper border of the acetabulum; in front and behind by the anterior 
and posterior borders. This surface is crossed in an arched direction by three 
semicircular lines-the superior, middle, and inferior curved lines. The superior 
curved line, or the posterior gluteal line (linea glutoea posterior), the shortest of the 
three, commences at the crest, about two inches in front of its posterior extremity; 
it is at first distinctly marked, but as it passes downward and backward to the 
upper part of the great sacro-sciatic notch, where it terminates, it becomes less 
marked, and is often altogether lost. Behind this line is a narrow semilunar 
surface, the upper part of which is rough and affords attachment to part of 
the Gluteus maximus; the lower part is smooth and has no muscular fibres 
attached to it. The middle curved line, or the anterior gluteal line (linea glulam 
anterior), the longest of the three, commences at the crest, about an inch 
behind its anterior extremity, and, taking a curved direction downward and 
backward, terminates at the upper part of the great sacro-sciatic notch. The 
space between the superior and middle curved lines and the crest is concave, 
and affords attachment to the Gluteus medius muscle. Near the central part 
of this line may often be observed the orifice of a nutrient foramen. The inferior THE SKELETON 
208 
curved or inferior gluteal line (tinea glulam inferior) ,the least distinct of the three, 
commences in front at the notch on the anterior border, and, taking a curved 
direction backward and downward, terminates at the middle of the great sacro- 
sciatic notch. The surface of bone included between the middle and inferior 
Anterior superior 
spine. 
Posterior 
superior 
spine. 
Posterior 
inferior- 
spine. 
■Anterior inferior spine. 
Ilio-pectineal line 
for GimbernaVs ligament. 
GEMELLUS SUPERIOR. 
Spine of ischium. 
'RECTUS ABDOMINIS. 
• PYRAMIDALIS. 
•ADDUCTOR LONQUS. 
GEMELLUS INFERIOR." 
Fig. 153.-Right os innominatum. External surface. 
curved lines is concave from above downward, convex from before backward, and 
affords attachment to the Gluteus minimus muscle. Beneath the inferior curved 
line, and corresponding to the upper part of the acetabulum, is a roughened sur- 
face (sometimes a depression), to which is attached the reflected tendon of the 
Rectus femoris muscle. 
Internal Surface.-The internal surface (Fig. 154) of the ilium is bounded above 
by the crest; below it is continuous with the pelvic surface of the os pubis and 
ischium, a faint line only indicating the place of union; and before and behind it THE OS INNOMINATUM 
209 
is bounded by the anterior and posterior borders. It presents a large, smooth, 
concave surface, called the iliac fossa, or venter ilii (fossa iliaca), which lodges the 
Iliacus muscle, and presents at its lower part the orifice of a nutrient canal (fora- 
men nutricium); and below this a smooth, rounded border, the ilio-pectineal line 
LEVATOR ANI. 
COMPRESSOR URETHRXE. 
Crus penis. 
TRANSVERSUS PERINEI. 
ERECTOR PENIS. 
Fig. 154.-Right os innominatum. Internal surface. 
or the linea ilio-pectinea (lined arcuata), which separates the iliac fossa from that 
portion of the internal surface which enters into the formation of the true pelvis, 
and which gives attachment to part of the Obturator internus muscle. Behind 
the iliac fossa is a rough surface divided into two portions, an anterior and 
a posterior. The anterior or auricular surface (facies auricular is), so called from 
its resemblance in shape to the ear, is coated with cartilage in the recent state, 
and articulates with a surface of similar shape on the side of the sacrum. The 
posterior portion (tuberositas iliaca) is rough, for the attachment of the posterior 
sacro-iliac ligaments and for a part of the origin of the Erector and Multifidus 210 
THE SKELETON 
spinae. In many bones a furrow exists in front, under and behind the auricular 
surface. This furrow is the paraglenoid sulcus (sulcus paraglenoidalis), and it 
affords attachment to the sacro-sciatic ligaments. 
The Crest of the Ilium (crista iliaca).-The crest of the ilium is convex in its 
general outline and sinuously curved, being concave inward in front, concave 
outward behind. It is longer in the female than in the male, very thick behind, 
and thinner at the centre than at the extremities. It terminates at either end in 
a prominent eminence, the anterior superior and posterior superior spinous process 
(spina iliaca anterior superior et spina iliaca posterior superior). The surface of 
the crest is broad, and divided into an external lip (labium externum), an inter- 
nal lip (labium internum), and an intermediate space (linea intermedia). About 
two inches behind the anterior superior spinous process there is a prominent 
tubercle on the outer lip. To the external lip is attached the Tensor fasciae 
femoris, Obliquus externus abdominis, and Latissimus dorsi, and along its 
whole length, the fascia lata; to the space between the lips, the Internal oblique; 
to the internal lip, the Transversalis, Quadratus lumborum, and Erector spinae, 
the Iliacus, and the fascia iliaca. 
Anterior Border.-The anterior border of the ilium is concave. It presents two 
projections, separated by a notch. Of these, the uppermost, situated at the junc- 
tion of the crest and anterior border, is called the anterior superior spinous process 
of the ilium (spina iliaca anterior superior), the outer border of which gives 
attachment to the fascia lata and the origin of the Tensor fasciae femoris (tensor 
vagina? femoris)', its inner border, to the Iliacus; while its extremity affords attach- 
ment to Poupart's ligament and the origin of the Sartorius. Beneath this emi- 
nence is a notch which gives attachment to the Sartorius muscle, and across 
which passes the external cutaneous nerve. Below the notch is the anterior 
inferior spinous process (spina iliaca anterior inferior), which terminates in the 
upper lip of the acetabulum; it gives attachment to the straight tendon of 
the Rectus femoris muscle and the ilio-femoral ligament. On the inner side of the 
anterior inferior spinous process is a broad, shallow groove, over which passes 
the Ilio-psoas muscle. This groove is bounded internally by an eminence, the 
ilio-pectineal eminence (eminentia iliopectinea), which marks the point of union 
of the ilium and os pubis. 
Posterior Border.-The posterior border of the ilium, shorter than the anterior, 
also presents two projections separated by a notch, the posterior superior spinous 
process (spina iliaca posterior superior) and the posterior inferior spinous process 
(spina iliaca posterior inferior). The former corresponds with that portion of 
the inner surface of the ilium which serves for the attachment of the oblique 
portion of the sacro-iliac ligaments and the Multifidus spinre muscle; the latter, 
to the auricular portion which articulates with the sacrum. Below the pos- 
terior inferior spinous process is a deep notch, the great sciatic, ilio-sciatic, or 
the great sacro-sciatic notch (incisura ischiadica major). 
The Ischium (os ischii).-The ischium forms the lower and back part of the 
os innominatum. It is divisible into a thick and solid portion-the body; a large, 
rough eminence, on which the trunk rests in sitting-the tuberosity; and a thin 
part which passes forward and slightly upward-the ramus. 
The Body (corpus ossis ischii).-The body, somewhat triangular in form, pre- 
sents three surfaces, external, internal, and posterior; and three borders, external, 
internal, and posterior. The external surface corresponds to that portion of the 
acetabulum formed by the ischium; it is smooth and concave, and forms a 
little more than two-fifths of the acetabular cavity; its outer margin is bounded 
by a prominent rim or lip, the external border, to which the cotyloid fibro- 
cartilage is attached. Below the acetabulum, between it and the tuberosity, is 
a deep groove, along which the tendon of the Obturator externus muscle runs THE OS INNOMINATUM 
211 
as it passes outward to be inserted into the digital fossa of the femur. The 
internal surface is smooth, concave, and enters into the formation of the lateral 
boundary of the true pelvic cavity. This surface is perforated by two or three 
large, vascular foramina, and affords attachment to part of the Obturator inter- 
nus muscle. The posterior surface is quadrilateral in form, broad and smooth. 
Below, where it joins the tuberosity, it presents a groove, the obturator groove 
(sulcus obturatorius), continuous with that on the external surface, for the tendon 
of the Obturator externus muscle. The lower edge of this groove is formed by 
the tuberosity of the ischium, and affords attachment to the Gemellus inferior 
muscle. This surface is limited, externally, by the margin of the acetabulum; 
behind, by the posterior border; it supports the Pyriformis, the two Gemelli, and 
the Obturator interims muscles in their passage outward to the great trochanter. 
The external border forms the prominent rim of the acetabulum, and separates 
the posterior from the external surface. To it is attached the cotyloid fibro- 
cartilage. The internal border is thin, and forms the outer circumference of the 
obturator foramen. The posterior border of the body of the ischium presents, a 
little below the centre, a thin and pointed, triangular eminence, the spine of the 
ischium (spina ischiadica), more or less elongated in different subjects; its exter- 
nal surface gives attachment to the Gemellus superior, its internal surface to 
the Coccygeus and Levator ani; whilst to the pointed extremity is connected the 
lesser sacro-sciatic ligament. Above the spine is a notch of large size, the great 
sacro-sciatic notch (incisura ischiadica major), converted into a foramen, the great 
sacro-sciatic foramen (foramen ischiadicum majus), by the lesser sacro-sciatic liga- 
ment; it transmits the Pyriformis muscle, the gluteal vessels, and superior and 
inferior gluteal nerves; the sciatic vessels, the greater and lesser sciatic nerves, 
the internal pudic vessels and nerve, and the nerves to the Obturator interims and 
Quadratus femoris. Of these, the gluteal vessels and superior gluteal nerve pass 
out above the Pyriformis muscle, the other structures, below it. Below the spine 
is a smaller notch, the lesser sacro-sciatic notch (incisura ischiadica minor); it is 
smooth, coated in the recent state with cartilage, the surface of which presents 
two or three ridges corresponding to the subdivisions of the tendon of the Obtu- 
rator internus, which winds over it. It is converted into a foramen, the lesser 
sacro-sciatic foramen (foramen ischiadicum minus), by the sacro-sciatic ligaments, 
and transmits the tendon of the Obturator internus, the nerve which supplies 
that muscle, and the internal pudic vessels and nerve. 
The Tuberosity of the Ischium (tuber ischiadicum).-The tuberosity of the 
ischium is the portion of bone between the body and the ascending ramus. 
Some anatomists name this portion of bone the descending or superior ramus 
(ramus superior ossis ischii), and restrict the term tuberosity to the surface of 
the bone which is rough, and is directed backward and outward. The tuber- 
osity presents for examination three surfaces: external, internal, and posterior. 
The external surface is quadrilateral in shape, and rough for the attachment of 
muscles. It is bounded above by the groove for the tendon of the Obturator 
externus; in front it is limited by the posterior margin of the obturator foramen, 
and below it is continuous with the ramus of the bone; behind, it is bounded by 
a prominent margin which separates it from the posterior surface. In front of 
this margin the surface gives attachment to the Quadratus femoris, and anterior 
to this to some of the fibres of origin of the Obturator externus. The lower part 
of the surface gives origin to part of the Adductor magnus. The internal sur- 
face forms part of the bony wall of the true pelvis. In front it is limited by the 
posterior margin of the obturator foramen. Behind, it is bounded by a sharp 
ridge, for the attachment of a falciform prolongation of the great sacro-sciatic 
ligament; it sometimes presents a groove on the inner side of this ridge for the 
lodgement of the internal pudic vessels and nerve; and, more anteriorly, has 212 
THE SKELETON 
attached the Transversus perinsei and Erector penis muscles. The posterior 
surface is divided into two portions-a lower rough, somewhat triangular part, 
and an upper smooth, quadrilateral portion. The anterior portion is subdivided 
by a prominent vertical ridge, passing from base to apex, into two parts; the 
outer one gives attachment to the Adductor magnus; the inner to the great sacro- 
sciatic ligament. The upper portion is subdivided into two facets by an oblique 
ridge which runs downward and outward; from the upper and outer facet arises 
the Semimembranosus; from the lower and inner, the Biceps and Semitendinosus. 
The Ramus or Inferior Ramus or Ascending Ramus of the Ischium (ramus inferior 
ossis ischii).-The ramus is the thin, flattened part of the ischium which ascends 
from the tuberosity upward and inward, and joins the descending ramus of the 
os pubis, their point of junction being indicated in the adult by a rough line. 
The outer surface of the ramus is rough, for the attachment of the Obturator 
externus muscle, and also some fibres of the Adductor magnus; its inner sur- 
face forms part of the anterior wall of the pelvis. Its inner border is thick, 
rough, slightly everted, forms part of the outlet of the pelvis, and presents two 
ridges and an intervening space. The ridges are continuous with similar ones 
on the descending ramus of the os pubis: to the outer one is attached the deep 
layer of the superficial perineal fascia, and to the inner, the superficial layer of 
the triangular ligament of the urethra. If these two ridges are traced downward, 
they will be found to join with each other just behind the point of origin of the 
Transversus perinsei muscle; here the two layers of fascia are continuous behind 
the posterior border of the muscle. To the intervening space, just in front of the 
point of junction of the ridges, is attached the Transversus perinsei muscle, and 
in front of this a portion of the crus penis vel clitoridis and the Erector penis vel 
clitoridis muscle. Its outer border is thin and sharp, and forms part of the inner 
margin of the obturator foramen. 
The Pubis (bs pubis).-The os pubis forms the anterior part of the os innomi- 
natum, and, with the bone of the opposite side, forms the front boundary of the 
true pelvic cavity. It is divisible into a body, an ascending and a descending ramus. 
The Body (corpus ossis pubis).-The body is the broad portion of bone formed 
by the junction of the two rami. It is somewhat quadrilateral in shape, and 
presents for examination two surfaces and three borders. The anterior surface 
is rough, directed downward and outward, and serves for the attachment of 
various muscles. To the upper and inner angle, immediately below the crest, 
is attached the Adductor longus; lower down, from without inward, are attached 
the Obturator externus, the Adductor brevis, and the upper part of the Gracilis. 
The posterior surface, convex from above downward, concave from side to side, 
is smooth, and forms part of the anterior wall of the pelvis. It gives attach- 
ment to the Levator ani, Obturator internus, a few muscular fibres prolonged 
from the bladder, and the pubo-prostatic ligaments. The upper border presents 
for examination a prominent tubercle, which projects forward and is called the 
spine (tuber culum pubicum); to it are attached the outer pillar of the external 
abdominal ring and Poupart's ligament. Passing upward and outward from 
this is a prominent ridge, forming part of the ilio-pectineal line (tinea arcuata), 
and called the pecten ossis pubis. It marks the brim of the true pelvis: to it are 
attached a portion of the conjoined tendon of the Internal oblique and Trans- 
versalis muscles, Gimbernat's ligament, and the triangular fascia of the abdomen. 
Internal to the spine of the os pubis is the crest, which extends from this process 
to the inner extremity of the bone. It affords attachment, anteriorly, to the con- 
joined tendon of the Internal oblique and Transversalis; and posteriorly, to the 
Rectus and Pyramidalis muscles. The point of junction of the crest with the 
inner border of the bone (symphysis) is called the angle; to it, as well as to the 
symphysis, is attached the internal pillar of the external abdominal ring. The THE OS 1NNOMINATUM 
213 
internal border is articular; it is oval, covered by eight or nine transverse ridges, 
or a series of nipple-like processes arranged in rows, separated by grooves; they 
serve for the attachment of a thin layer of cartilage, placed between it and the 
central fibro-cartilage. The outer border presents a sharp margin, which forms 
part of the circumference of the obturator foramen and affords attachment to 
the obturator membrane. 
The Ascending or Superior Ramus of the Pubis (ramus superior ossis pubis).- 
The ascending or superior ramus extends from the body to the point of junction 
of the os pubis with the ilium, and forms the upper part of the circumference of 
the obturator foramen. It presents for examination a superior, inferior, and 
posterior surface, and an outer extremity. The superior surface presents a con- 
tinuation of the ilio-pectineal line, already mentioned as commencing at the 
pubic spine. In front of this ridge the surface of bone is triangular in form, 
wider externally than internally, smooth, and is covered by the Pectineus muscle. 
The surface is bounded externally by a rough eminence, the ilio-pectineal emi- 
nence (eminentia iliopectinea), which serves to indicate the point of junction of 
the ilium and os pubis, and gives attachment to the Psoas parvus, when this 
muscle is present. The triangular surface is bounded below by a prominent 
ridge, the obturator crest (crista obturatoria), which extends from the cotyloid 
notch to the spine of the os pubis. The inferior surface forms the upper bound- 
ary of the obturator foramen, and presents externally a broad and deep oblique 
groove, the obturator groove (sulcus obturatorius), for the passage of the obturator 
vessels and nerve; and internally a sharp margin which forms part of the cir- 
cumference of the obturator foramen, and to which the obturator membrane is 
attached. The posterior surface forms part of the anterior boundary of the true 
pelvis. It is smooth, convex from above downward, and affords attachment to 
some fibres of the Obturator internus. The outer extremity, the thickest part of 
the ramus, forms one-fifth of the cavity of the acetabulum. 
The Descending or Inferior Ramus of the Pubis (ramus inferior ossis pubis).- 
The descending or inferior ramus of the os pubis is thin and flattened. It passes 
outward and downward, becoming narrower as it descends, and joins with the 
ramus of the ischium. Its anterior surface is rough, for the attachment of muscles 
-the Gracilis along its inner border; a portion of the Obturator externus where it 
enters into the formation of the foramen of that name; and between these two 
muscles the Adductores brevis and magnus from within outward. The posterior 
surface is smooth, and gives attachment to the Obturator internus, and, close to 
the inner margin, to the Compressor urethrae. The inner border is thick, rough, 
and everted, especially in females. It presents two ridges, separated by an inter- 
vening space. The ridges extend downward, and are continuous with similar 
ridges on the ascending ramus of the ischium; to the external one is attached 
the deep layer of the superficial perineal fascia, and to the internal one the super- 
ficial layer of the triangular ligament of the urethra. The older border is thin 
and sharp, forms part of the circumference of the obturator foramen, and gives 
attachment to the obturator membrane. 
The Cotyloid Cavity or Acetabulum.-The cotyloid cavity, or acetabulum, is 
a deep, cup-shaped, hemispherical depression, directed downward, outward, and 
forward; formed internally by the os pubis, above by the ilium, behind and below 
by the ischium, a little less than two-fifths being formed by the ilium, a little more 
than two-fifths by the ischium, and the remaining fifth by the pubic bone. It is 
bounded by a prominent, uneven rim, which is thick and strong above, and serves 
for the attachment of the cotyloid ligament, which contracts its orifice and deepens 
the surface for articulation. It presents below a deep notch, the cotyloid notch 
(incisura acetabuli), which is continuous with a circular depression, the fossa cf 
the acetabulum (fossa acetabuli), at the bottom of the cavity: this depression is THE SKELETON 
214 
perforated by numerous apertures, lodges a mass of fat, and its margins, as well 
as those of the notch, serve for the attachment of the ligamentum teres. In front, 
above and behind the fossa acetabuli, is a concave rim of bone (facies lunata). The 
cotyloid notch is converted, in the natural state, into a foramen by a dense liga- 
mentous band which passes across it. Through this foramen the nutrient vessels 
and nerves enter the joint. 
The Obturator or Thyroid Foramen (foramen obturatum).-The obturator or 
thyroid foramen is a large aperture situated between the ischium and os pubis. 
In the male it is large, of an oval form, its longest diameter being obliquely from 
before backward; in the female it is smaller and more triangular. It is bounded 
by a thin, uneven margin, to which a strong membrane is attached, and presents, 
anteriorly, a deep groove, the obturator groove (sulcus obturatorius), which runs 
from the pelvis obliquely inward and downward. This groove is converted into 
a foramen by the obturator membrane, and transmits the obturator vessels and 
nerve. 
Structure.-This bone consists of much cancellous tissue, especially where it 
is thick, enclosed between two layers of dense, compact tissue. In the thinner 
parts of the bone, as at the bottom of the acetabulum and centre of the iliac 
fossa, it is usually semitransparent, and composed entirely of compact tissue. 
Development (Fig. 155).-By eight centres: three primary-one for the ilium, 
one for the ischium, and one for the os pubis; and five secondary-one for the 
By eight centres 
Three primary (Ilium, Ischium, and Os Pubis). 
Five secondary. 
Off 
Anterior inferior spine.. 
8. Symphysis pubis.\ 
The three primary centres unite through a Y-shaped piece about puberty. 
Epiphyses appear about puberty, and unite about the twenty-fifth year. 
Fig. 155.-Plan of the development of the os innominatum. 
crest of the ilium, one for the anterior inferior spinous process (said to occur more 
frequently in the male than in the female), one for the tuberosity of the ischium, 
one for the symphysis pubis (more frequent in the female than the male), and one 
or more for the Y-shaped piece at the bottom of the acetabulum. These various 
centres appear in the following order: First, in the ilium, at the lower part of THE PELVIS 
215 
the bone, immediately above the sciatic notch, at about the eighth or ninth week; 
secondly, in the body of the ischium, at about the third month of foetal life; 
thirdly, in the body of the os pubis, between the fourth and fifth months. At 
birth the three primary centres are quite separate, the crest, the bottom of the 
acetabulum, the ischial tuberosity, and the rami of the ischium and pubes being 
still cartilaginous. At about the seventh or eighth year the rami of the os pubis 
and ischium are almost completely united by bone. About the thirteenth or 
fourteenth year the three divisions of the bone have extended their growth into 
the bottom of the acetabulum, being separated from each other by a Y-shaped 
portion of cartilage, which now presents traces of ossification, often by two or 
more centres. One of these, the os acetabuli, appears about the age of twelve, 
between the ilium and os pubis, and fuses with them about the age of eighteen. 
It forms the pubic part of the acetabulum. The ilium and ischium then become 
joined, and lastly the os pubis to the ischium, through the intervention of this 
Y-shaped portion. At about the age of puberty ossification takes place in each 
of the remaining portions, and they become joined to the rest of the bone 
between the twentieth and twenty-fifth years. Separate centres are frequently 
found for the pubic and ischial spines 
Articulations.-With its fellow of the opposite side, the sacrum, and femur. 
Attachment of Muscles.-To the ilium, sixteen. To the outer lip of the crest, 
the Tensor vaginae femoris, Obliquus externus abdominis, and Latissimus dorsi; 
to the internal lip, the Iliacus, Transversalis, Quadratus lumborum, and Erector 
spinae; to the interspace between the lips, the Obliquus interims. To the outer 
surface of the ilium, the Gluteus maximus, Gluteus medius, Gluteus minimus, 
reflected tendon of the Rectus; to the upper part of the great sacro-sciatic notch, a 
portion of the Pyriformis; to the internal surface, the Iliacus; to that portion of 
the internal surface below the linea ilio-pectinea, the Obturator internus to the 
internal surface of the posterior superior spine, and the Multifidus spinae; to the 
anterior border, the Sartorius and straight tendon of the Rectus. To the ischium, 
thirteen. To the outer surface of the ramus, the Obturator externus and Adductor 
magnus; to the internal surface, the Obturator internus and Erector penis. To the 
spine, the Gemellus superior, Levator ani, and Coccygeus. To the tuberosity, the 
Biceps, Semitendinosus, Semimembranosus, Quadratus femoris, Adductor mag- 
nus, Gemellus inferior, Transversus perimei, Erector penis. To the pubis, 
sixteen: Obliquus externus, Obliquus internus, Transversalis, Rectus, Pyramid- 
alis, Psoas parvus, Pectineus, Adductor magnus, Adductor longus, Adductor 
brevis, Gracilis, Obturator externus and internus, Levator ani, Compressor 
urethne, and occasionally a few fibres of the Accelerator urinse. 
The Pelvis (Figs. 156, 157). 
The pelvis, so called from its resemblance to a basin (L. pelvis), is stronger 
and more massively constructed than either the cranial or thoracic cavity; it is a 
bony ring, interposed between the lower end of the spine, which it supports, and 
the lower extremities, upon which its rests. It is composed of four bones: the two 
ossa innominata, which bound it on either side and in front, and the sacrum and 
coccyx, which complete it behind. The pelvis is divided by an oblique plane 
passing through the prominence of the sacrum, the linea ilio-pectinea, and the 
upper margin of the symphysis pubis into the false and true pelvis. 
The False Pelvis (pelvis major).-The false pelvis is the expanded portion of 
the pelvic cavity which is situated above this plane. It is bounded on each side 
by the ossa ilii; in front it is incomplete, presenting a wide interval between the 
spinous processes of the ilia on either side, which is filled up in the recent state by 
the parietes of the abdomen; behind, in the middle line, is a deep notch. This THE SKELETON 
216 
broad, shallow cavity is fitted to support the intestines and to transmit part of 
their weight to the anterior wall of the abdomen, and is, in fact, really a portion 
of the abdominal cavity. The term false pelvis is incorrect, and this space ought 
Fig. 156.-Male pelvis (adult). 
more properly to be regarded as part of the hypogastric and iliac regions of the 
abdomen. 
The True Pelvis (pelvis minor).-The true pelvis is that part of the pelvic 
cavity which is situated beneath the plane. It is smaller than the false pelvis, 
Fig. 157.-Female pelvis (adult). 
but its walls are more perfect. For convenience of description it is divided 
into a superior circumference or inlet, an inferior circumference or outlet, and a 
cavity. THE PELVIS 
217 
The Superior Circumference or Inlet (apertura pelvis superior).-The superior cir- 
cumference forms the brim of the pelvis, the included space being called the inlet. 
It is formed by the linea ilio-pectinea, completed in front by the crests of the 
pubic bones, and behind by the anterior margin of the base of the sacrum and 
sacro-vertebral angle. The brim of the pelvis is the name often given to the 
margin of the inlet. The inlet of the pelvis is somewhat heart-shaped, obtusely 
pointed in front, diverging on either side, and encroached upon behind by the 
projection forward of the promontory of the sacrum. It has three principal 
diameters: antero-posterior (sacro-pubic), transverse, and oblique. The antero- 
posterior or conjugate diameter (conjugata) extends from the sacro-vertebral angle 
to the symphysis pubis. The anatomical conjugate (conjugata anatomica) is the 
distance between the sacro-vertebral angle and the top of the symphysis pubis. 
Its average measurement is four inches in the male and four and three-fifths inches 
in the female. The true, available, or obstetric conjugate (conjugata gyncecologica) 
is the distance between the sacro-vertebral angle and the nearest point upon the 
symphysis. This point is a little behind and below the upper margin (Webster). 
The average distance in women is four and three-eighths inches. The diagonal 
conjugate (diagonalconjugata) is measured from the sacro-vertebral angle to the 
subpubic ligament. The distance exceeds the true conjugate by one-half or two- 
thirds of an inch. The transverse diameter (diameter transversa) extends across 
the greatest width of the inlet, from the middle of the brim on one side to the 
same point on the opposite; its average measurement is five inches in the male, 
five and one-fourth inches in the female. The oblique diameter (diameter obliqua) 
extends from the margin of the pelvis, corresponding to the ilio-pectineal eminence 
on one side, to the sacro-iliac articulation on the opposite side; its average 
measurement is four and a quarter inches in the male and five in the female. The 
oblique diameters are named right or left oblique, according to the sacro-iliac 
joint from which the measurement is taken. 
The Cavity.-The cavity of the true pelvis is bounded in front by the symphysis 
pubis; behind, by the concavity of the sacrum and coccyx, which, curving forward 
above and below, contracts the inlet and outlet of the canal; and laterally it is 
bounded by a broad, smooth, quadrangular surface of bone, corresponding to the 
inner surface of the body of the ischium and that part of the ilium which is below 
the ilio-pectineal line. The cavity is shallow in front, measuring at the symphy- 
sis an inch and a half in depth, three inches and a half in the middle, and four 
inches and a half posteriorly. From this description it will be seen that the cavity 
of the pelvis is a short, curved canal, considerably deeper on its posterior than 
on its anterior wall. This cavity contains, in the recent subject, the rectum, 
bladder, and part of the organs of generation. The rectum is placed at the back 
of the pelvis, and corresponds to the curve of the sacro-coccygeal column; the 
bladder in front, behind the symphysis pubis. In the female the uterus and 
vagina occupy the interval between these viscera. 
The Lower Circumference or Outlet (apertura pelvis inferior).-The lower cir- 
cumference of the pelvis is very irregular, and forms what is called the outlet. 
It is bounded by three prominent eminences: one posterior, formed by .the point 
of the coccyx; and one on each side, the tuberosities of the ischia. These emi- 
nences are separated by three notches; one in front, the pubic arch (arcus pubis), 
formed by the convergence of the rami of the ischia and pubic bones on each 
side. The other notches, one on each side, are formed by the sacrum and coccyx 
behind, the ischium in front, and the ilium above; they are called the sacro-sciatic 
notches; in the natural state they are converted into foramina by the lesser and 
greater sacro-sciatic ligaments. In the recent state, when the ligaments are in 
situ, the outlet of the pelvis is lozenge-shaped, bounded in front by the subpubic 
ligament and the rami of the os pubis and ischium; on each side by the tuber- THE SKELETON 
218 
osities of the ischia; and behind by the great sacro-sciatic ligaments and the tip 
of the coccyx. 
The diameters of the outlet of the pelvis are two, antero-posterior and trans- 
verse. The antero-posterior (conjugate) diameter (diameter recta of the outlet) 
extends from the tip of the coccyx to the lower part of the symphysis pubis; its 
average measurement is three and three-quarter inches in the male and four and 
one-half inches in the female. The antero-posterior diameter varies with the 
length of the coccyx, and is capable of increase or diminution on account of the 
mobility of that bone. During labor the coccyx may be bent back so that the 
conjugate is increased one inch, or even one and one-fourth inches. The trans- 
verse diameter extends from the posterior part of one ischiatic tuberosity to the 
same point on the opposite side: the average measurement is three and a half 
inches in the male and four and three-fourths in the female.1 
Oblique diameters are not employed, as there are no fixed points from which 
to measure them. 
Position of the Pelvis.-In the erect posture the pelvis is placed obliquely with 
regard to the trunk of the body: the bony ring, which forms the brim of the true 
pelvis, is placed so as to form an angle of about 60 to 65 degrees with the ground 
on which we stand (inclinatio pelvis). The pelvic surface of the symphysis pubis 
looks upward and backward, the concavity of the sacrum and coccyx downward 
and forward, the base of the sacrum in well-formed female bodies being nearly 
four inches above the upper border of the symphysis pubis, and the apex of the 
coccyx a little more than half an inch above its 
lower border. In consequence of the obliquity 
of the pelvis the line of gravity of the head, 
which passes through the middle of the odontoid 
process of the axis and through the points of 
junction of the curves of the vertebral column to 
the sacro-vertebral angle, descends toward the 
front of the cavity, so that it bisects a line 
drawn transversely through the middle of the 
heads of the thigh bones. And thus the centre 
of gravity of the head is placed immediately 
over the heads of the thigh bones on which the 
trunk is supported. 
Axes of the Pelvis (Fig. 158).-The plane of 
the inlet of the true pelvis will be represented by 
a line drawn from the base of the sacrum to the 
upper margin of the symphysis pubis. A line 
carried at right angles with this at its middle 
would correspond at one extremity with the 
umbilicus, and at the other with the middle of 
the coccyx: the axis of the inlet is therefore directed downward and backward. 
The axis of the outlet, produced upward, would touch the base of the sacrum, 
and is therefore directed downward and forward. The axis of the cavity is curved 
like the cavity itself: this curve corresponds to the concavity of the sacrum 
and coccyx, the extremities being indicated by the central points of the inlet and 
Fig. 158.-Vertical section of the pelvis, 
with lines indicating the axis of the pelvis. 
1 The measurements of the pelvis given above are, I believe, fairly accurate, but different measurements are 
given by various authors, no doubt due in a great measure to differences in the physique and stature of the 
population from whom the measurements have been taken. The accompanying chart has been formulated to 
show the measurements of the pelvis which are adopted by many obstetricians.-Ed. 
Antero-posterior. 
Oblique. 
Transverse. 
Of inlet 
. 43/s inches (118 mm.) 
5 inches (127 mm.) 
5)4 inches (135 mm.) 
Of outlet . 
. 4% inches (115 mm.) 
4% inches (120 mm.) 
Diameters of the True Pelvis in Woman. THE PELVIS 
219 
outlet. A knowledge of the direction of these axes serves to explain the course 
of the foetus in the passage through the pelvis during parturition. It is also 
important to the surgeon, as indicating the direction of the force required in the 
removal of calculi from the bladder by the sub-pubic operation, and as deter- 
mining the direction in which instruments should be used in operations upon the 
pelvic viscera. 
Differences between the Male and the Female Pelvis.-The female pelvis, 
looked at as a whole, is distinguished from the male by the bones being more 
delicate, by its width being greater and its depth smaller. The whole pelvis is 
less massive, and its bones are lighter and more slender, and its muscular impres- 
sions are slightly marked. The iliac fossre are shallow, and the anterior iliac spines 
widely separated; hence the greater prominence of the hips. The inlet in the 
female is larger than in the male; it is more nearly circular, and the sacro-vertebral 
angle projects less forward. The cavity is shallower and wider; the sacrum is 
shorter, wider, and less curved; the obturator foramina are triangular, and smaller 
in size than in the male. The outlet is larger and the coccyx more movable. The 
spines of the ischia project less inward. The tuberosities of the ischia and the 
acetabula are wider apart. The pubic arch is wider and more rounded than in the 
male, where it is an angle rather than an arch. In consequence of this the width of 
the fore part of the pelvic outlet is much increased and the passage of the foetal 
head facilitated. 
The size of the pelvis varies, not only in the two sexes, but also in different 
members of the same sex. This does not appear to be influenced in any way by 
Fig. 159.-Diameters of the pelvic inlet. 
the height of the individual. Women of short stature, as a rule, have broad pelves. 
Occasionally the pelvis is equally contracted in all its dimensions, so much so that 
all its diameters measure an inch less than the average, and this even in women 
of average height and otherwise well formed. The principal divergences, however, 
are found at the inlet, and affect the relation of the antero-posterior to the trans- 
verse diameter. Thus we may have a pelvis the inlet of which is elliptical either 
in a transverse or antero-posterior direction; the transverse diameter in the former 
and the antero-posterior in the latter greatly exceeding the other diameters. Again, 
the inlet of the pelvis in some instances is seen to be almost circular. The same 
differences are found in various races. European women are said to have the 220 
THE SKELETON 
most roomy pelves. That of the negress is smaller, circular in shape, and with a 
narrow pubic arch. The Hottentots and Bushwomen possess the smallest pelves. 
In the foetus and for several years after birth the pelvis is small in proportion 
to that of the adult. The cavity is deep, and the projection of the sacro-vertebral 
angle less marked. The generally accepted opinion that the female pelvis does 
not acquire its sexual characters until after puberty has been shown by recent 
Fig. 160.-Diameters of the pelvic outlet. 
observations1 to be erroneous, the characteristic differences between the male and 
female pelvis being distinctly indicated as early as the fourth month of foetal life. 
At birth these differences are distinct (Romiti), the female pelvis possessing less 
straight ilia, a broader subpubic arch, and less height than the male. 
Surface Form.-The pelvic bones are so thickly covered with muscles that it is only at 
certain points that they approach the surface and can be felt through the skin. In front, 
the anterior superior spinous process is easily recognized; a portion of it is subcutaneous, 
and in thin subjects may be seen to stand out as a prominence at the outer extremity of the fold 
of the groin. In fat subjects its position is marked by an oblique depression amongst the sur- 
rounding fat, at the bottom of which the bony process may be felt. Proceeding upward and 
outward from this process, the crest of the ilium may be traced throughout its whole length, 
sinuously curved. It is represented, in muscular subjects, on the surface, by a groove or fur- 
row, the iliac furrow, caused by the projection of fleshy fibres of the External oblique muscles 
of the abdomen; the iliac furrow lies slightly below the level of the crest. It terminates behind 
in the posterior superior spinous process, the position of which is indicated by a slight depression 
on a level with the spinous process of the second sacral vertebra. Between the two posterior 
superior spinous processes, but at a lower level, is to be felt the spinous process of the third 
sacral vertebra (see page 69). Another part of the bony pelvis easily accessible to touch is the 
tuberosity of the ischium, situated beneath the gluteal fold, and, when the hip is flexed, it is 
easily felt, as it is then to a great extent uncovered by muscle. Finally, the spine of the os 
pubis can always be readily felt, and constitutes an important surgical guide, especially in con- 
nection with the subject of hernia. It is nearly in the same horizontal line with the upper edge 
of the great trochanter. In thin subjects it is very apparent, but in the obese it is obscured by 
the pubic fat. It can, however, be detected by following up the tendon of origin of the 
Adductor longus muscle. 
Surgical Anatomy.-There is arrest of development in the bones of the pelvis in cases 
of extroversion of the bladder; the anterior part of the pelvic girdle being deficient, the bodies 
of the pubic bones imperfectly developed, and the symphysis absent. The pubic bones are 
separated to the extent of from two to four inches, the superior rami shortened and directed 
forward, and the obturator foramen diminished in size, narrowed, and turned outward. The 
1 Fehling, Zeitschr. fiir Geburt. u. Gynaek., Bd. ix. und x.; and Arthur Thomson, Journal of Anatomy and 
Physiology, vol. xxxiii. THE FEMUR, OR THIGH BONE 
221 
iliac bones are straightened out more than normal. The sacrum is very peculiar. The lateral 
curve, instead of being concave, is flattened out or even convex, with the ilio-sacral facets turned 
more outward than normal, while the vertical curve is straightened.1 
Fractures of the pelvis are divided into fractures of the false pelvis and of the true pelvis. 
Fractures of the false pelvis vary in extent: a small portion of the iliac crest may be broken or 
one of the spinous processes may be torn off, and this may be the result of muscular action; or 
the bone may be extensively comminuted. This latter accident is the result of some crushing 
violence, and may be complicated with fracture of the true pelvis. These cases may be accom- 
panied by injury to the intestine as it lies in the hollow of the bone, or to the iliac vessels as 
they course along the margin of the true pelvis. Fractures of the true pelvis generally occur 
through the ascending ramus of the os pubis and the ramus of the ischium, as this is the weakest 
part of the bony ring, and may be caused either by crushing violence applied in an antero- 
posterior direction, when the fracture occurs from direct force, or by compression laterally, 
when the acetabula are pressed together, and the bone gives way in the same place from indirect 
violence. Occasionally the injury may be double, a break occurring on both sides of the body. 
In fracture of the true pelvis the contained viscera are liable to be damaged: the small intestines, 
the urethra, the bladder, the rectum, the vagina, and even the uterus, in the female, have all 
been lacerated by a displaced fragment. Fractures of the acetabulum are occasionally met with: 
either a portion of the rim may be broken off, or a fracture may take place through the bottom 
of the cavity, and the head of the femur may be driven inward and project into the pelvic cavity. 
Separation of the Y-shaped cartilage at the bottom of the acetabulum may also occur in the 
young subject, dispersing the bone into its three anatomical portions. 
The sacrum is seldom broken. The cause is direct violence-i. e., blows, kicks, or falls 
on the part. The lesion may be complicated with injury to the nerves of the sacral plexus, 
leading to paralysis and loss of sensation in the lower extremity or to incontinence of faeces from 
paralysis of the Sphincter ani. 
The pelvic bones often undergo important deformity in rickets, the effect of which in the 
adult woman may interfere seriously with childbearing. The deformity is due mainly to the 
weight of the spine and trunk, which presses on the sacro-vertebral angle and greatly increases 
it, so that the antero-posterior diameter of the pelvis is diminished. But, in addition to this, 
the weight of the viscera on the venter ilii causes those bones to expand and the tuberosities of 
the ischia to incurve. In osteomalacia also great deformity may occur. The weight of the 
trunk causes an increase in the sacro-vertebral angle and a lessening of the antero-posterior 
diameter of the inlet, and at the same time the pressure of the acetabula on the heads of the 
thigh-bones causes these cavities, with the adjacent bone, to be pushed upwrard and backward, 
so that the oblique diameters of the pelvis are also diminished, and the cavity of the pelvis 
assumes a triradiate shape, with the symphysis pubis pushed forward. 
THE THIGH. 
The thigh is that portion of the lower extremity which is situated between the 
pelvis and the knee. It consists in the skeleton of a single bone, the femur. 
The Femur, or Thigh Bone (Figs. 161, 162). 
The femur (jemur, the thigh) is the longest,2 largest, and strongest bone in the 
skeleton, and almost perfectly cylindrical throughout the greater part of its extent. 
In the erect posture it is not vertical, being separated from its fellow above by 
a considerable interval, which corresponds to the entire breadth of the pelvis, but 
inclining gradually downward and inward, so as to approach its fellow toward 
its lower part, for the purpose of bringing the knee-joint near the line of gravity 
of the body. The degree of this inclination varies in different persons, and 
is greater in the female than the male, on account of the greater breadth of 
the pelvis. The femur, like other long bones, is divisible into a shaft and two 
extremities. 
Upper Extremity.-The upper extremity presents for examination a head, 
a neck, and a great and lesser trochanters. 
Head of the Femur (caput femoris).-The head, which is globular, and 
forms rather more than a hemisphere, is directed upward, inward, and a little 
1 Wood. Heath's Dictionary of Practical Surgery, i., 426. 
2 In a man six feet high it measures eighteen inches-one-fourth of the whole body. 222 
THE SKELETON 
OBTURATOR INTERNUS 
and qemelli. 
PYRIFORMIS. 
forward, the greater part of its 
convexity being above and in front. 
Its surface is smooth, coated with 
cartilage in the recent state, ex- 
cept at a little behind and below its centre, 
where is an ovoid depression '(fovea capitis 
femoris), for the attachment for the Ligamen- 
tum teres. 
The Neck of the Femur (collum femoris}.-The 
neck is a flattened pyramidal process of bone 
which connects the head with the shaft. It 
varies in length and obliquity at various periods 
in life and under different circumstances. The 
angle is widest in infancy, and becomes lessened 
during growth, so that at puberty it forms a 
gentle curve from the axis of the shaft. In the 
adult it forms an angle of about 130 degrees 
with the shaft, but varies in inverse proportion 
to the development of the pelvis and the stature. 
In consequence of the prominence of the hips 
and widening of the pelvis in the female, the 
neck of the thigh bone forms more nearly a right 
angle with the shaft than it does in man. It has 
been stated that the angle diminishes in old age 
and the direction of the neck becomes hori- 
zontal, but this statement is founded on insuffi- 
cient evidence. Sir George Humphry states 
that the angle decreases during the period of 
growth, but after full growth has been attained 
it does not usually undergo any change, even 
in old age. He further states that the angle 
varies considerably in different persons of the 
same age. It is smaller in short than in long 
bones, and when the pelvis is wide.1 The neck 
is flattened from before backward, contracted in 
the middle, and broader at its outer extremity, 
where it is connected with the shaft, than at 
its summit, where it is attached to the head. 
The vertical diameter of the outer half is in- 
creased bv the thickening of the lower edge, 
which slopes downward to join the shaft at the 
lesser trochanter, so that the outer half of the 
neck is flattened from before backward, and its 
vertical diameter measures one-third more than 
the antero-posterior. The inner half is smaller 
and of a more circular shape. The anterior 
surface of the neck is perforated by numerous 
vascular foramina. The posterior surface is 
smooth, and is broader and more concave than 
the anterior; it gives attachment to the posterior 
part of the capsular ligament of the hip-joint, 
about half an inch above the posterior intertro- 
chanteric line. The superior border is short and 
Depression for 
LIGAMENTUN TERES. 
Fig. 161.-Right femur. Anterior surface. 
1 Journal of Anatomy and Physiology. THE FEMUR, OR THIGH BONE 
223 
thick, and terminates externally at the great trochanter; its surface is perforated 
by large foramina. The inferior border, long and -narrow, curves a little back- 
ward, to terminate at the lesser trochanter. 
The Trochanters.-The trochanters (rpoyda), to run or roll) are prominent pro- 
cesses of bone which afford leverage to the muscles which rotate the thigh on its 
axis. They are two in number, the greater and the lesser. 
The great trochanter (trochanter major) is a large, irregular, quadrilateral eminence, 
situated at the outer side of the neck, at its junction with the upper part of the shaft. 
It is directed a little outward and backward, and in the adult is about three-quarters 
of an inch lower than the head. It presents for examination two surfaces and four 
borders. The external surface, quadrilateral in form, is broad, rough, convex, and 
marked by a prominent diagonal impression, which extends from the posterior 
superior to the anterior inferior angle, and serves for the attachment of the tendon 
of the Gluteus medius. Above the impression is a triangular surface, sometimes 
rough for part of the tendon of the same muscle, sometimes smooth for the inter- 
position of a bursa between that tendon and the bone. Below and behind the 
diagonal line is a smooth, triangular surface, over which the tendon of the Gluteus 
maximus muscle plays, a bursa being interposed. The internal surface is of much 
less extent than the external, and presents at its base a deep depression, the digital 
or trochanteric fossa (fossa troc hunt erica), for the attachment of the tendon of the 
Obturator externus muscle: above and in front of this an impression for the attach- 
ment of the Obturator internus and Gemelli. The superior border is free; it is thick 
and irregular, and marked near the centre by an impression for the attachment of 
the Pyriformis. The inferior border corresponds to the point of junction of the base 
of the trochanter with the outer surface of the shaft; it is marked by a rough, promi- 
nent, slightly curved ridge, which gives attachment to the upper part of the Vastus 
externus muscle. The anterior border is prominent, somewhat irregular, as well 
as the surface of bone immediately below it; it affords attachment at its outer 
part to the Gluteus minimus. The posterior border is very prominent, and appears 
as a free, rounded edge, which forms the back part of the digital fossa. 
The lesser trochanter (trochanter minor) is a conical eminence which varies in size 
in different subjects; it projects from the lower and back parts of the base of the neck. 
Its base is triangular, and connected with the adjacent parts of the bone by three 
well-marked borders: two of these are above-the internal border, continuous with 
the lower border of the neck, the external border with the posterior intertrochan- 
teric line-while the inferior border is continuous with the middle division of the 
linea aspera. Its summit, which is directed inward and backward, is rough, and 
gives insertion to the tendon of the Ilio-psoas. The Iliacus is also inserted into 
the shaft below the lesser trochanter between the Vastus internus in front and the 
Pectineus behind. 
A well-marked prominence of variable size, which projects from the upper and 
front part of the neck at its junction with the great trochanter, is called the tuber- 
cle of the femur; it is the point of meeting of five muscles: the Gluteus minimus 
externally, the Vastus externus below, and the tendon of the Obturator internus 
and Gemelli above. Running obliquely downward and inward from the tubercle 
is the spiral line of the femur, or anterior intertrochanteric line (linea intertrochan- 
terica); it winds round the inner side of the shaft, below the lesser trochanter, and 
terminates in the linea aspera, about two inches below this eminence. Its upper 
half is rough, and affords attachment to the ilio-femoral ligament of the hip-joint; 
its lower half is less prominent, and gives attachment to the upper part of the 
Vastus internus. Running obliquely downward and inward from the summit of 
the great trochanter on the posterior surface of the neck is a very prominent, 
well-marked ridge, the posterior intertrochanteric line (crista intertrochanterica). 
Its upper half forms the posterior border of the great trochanter, and its lower 224 
THE SKELETON 
OBTURATOR EXTERNUS. 
half runs downward and inward 
to the upper and back part of 
the lesser trochanter. A slight 
ridge sometimes commences about 
the middle of the posterior inter- 
trochanteric line, and passes ver- 
tically downward for about two 
inches along the back part of the 
shaft: it is called the linea quadrati, 
and gives attachment to the 
Quadratus femoris and a few 
fibres of the Adductor magnus 
muscles? 
The Shaft of the Femur {corpus 
femoris).-The shaft, almost cylin- 
drical in form, is a little broader 
above than in the centre, and 
somewhat flattened below, from 
before backward. It is slightly 
arched, so as to be convex in front 
and concave behind, where it is 
strengthened by a prominent lon- 
gitudinal ridge, the linea aspera. 
It presents for examination three 
borders, separating three surfaces. 
Of the three borders, one, the linea 
aspera, is posterior; the other two 
are placed laterally. 
The Linea Aspera. - The linea 
aspera (Fig. 162) is a prominent 
longitudinal ridge or crest, on the 
middle third of the bone, present- 
ing an external lip (labium laterale), 
an internal lip (labium mediale), 
and a rough intermediate space. 
Above, this crest is prolonged by 
three ridges. The most external 
ridge is very rough, and is con- 
tinued almost vertically upward to 
the base of the great trochanter. 
It is sometimes termed the gluteal 
ridge (tuberositas glutcea), and gives 
attachment to part of the Gluteus 
maximus muscle; its upper part is 
sometimes elongated into a rough- 
ened crest, on which is a more or 
less well-marked, rounded tuber- 
cle, a rudimental third trochanter 
(trochanter tertius). The middle 
ridge (linea pectinea), the least dis- 
Groove for tendon of 
POPLITEUS. 
1 Generally there is merely a slight thickening 
about the centre of the intertrochanteric line, 
marking the point of attachment of the Quad- 
ratus femoris. This is termed by some anato- 
mists the tubercle of the Quadratus. 
Fig. 162.-Right femur. Posterior surface. THE FEMUR, OR THIGH BONE 
225 
tinct, is continued to the base of the trochanter minor, and the internal ridge is 
lost above in the spiral line of the femur. Below, the linea aspera is prolonged 
by two ridges, which pass to the condyles and enclose between them a triangular 
space, the popliteal surface {planum popliteum), upon which rests the popliteal 
artery. Of these two ridges, the outer one is the more prominent, and descends 
to the summit of the outer condyle. The inner one is less marked, especially at 
its upper part, where it is crossed by the femoral artery. It terminates, below, 
at the summit of the internal condyle, in a small tubercle, the adductor tubercle, 
which affords attachment to the tendon of the Adductor magnus. To the inner 
lip of the linea aspera and its inner prolongation above and below is attached 
the Vastus internus, and to the outer lip and its outer prolongation above is 
attached the Vastus externus. The Adductor magnus is attached to the linea 
aspera, to its outer prolongation above and its inner prolongation below. Be- 
tween the Vastus externus and the Adductor magnus are attached two muscles 
-viz., the Gluteus maximus above, and the short head of the Biceps below. 
Between the Adductor magnus and the Vastus internus four muscles are attached: 
the Iliacus and Pectineus above, the Adductor brevis and Adductor longus below. 
A little below the centre of the linea aspera is the nutrient foramen (foramen 
nutriciurn), the orifice of the nutrient canal (canalis nutricius), which is directed 
obliquely upward (proximally). 
Lateral Borders.-The two lateral borders of the femur are only slightly marked, 
the outer one extending from the anterior inferior angle of the great trochanter 
to the anterior extremity of the external condyle; the inner one from the spiral line 
at a point opposite the trochanter minor, to the anterior extremity of the internal 
condyle. The internal border marks the limit of attachment of the Crureus muscle 
internally. 
Anterior Surface.-The anterior surface includes that portion of the shaft which 
is situated between the two lateral borders. It is smooth, convex, broader above 
and below than in the centre, slightly twisted, so that its upper part is directed 
forward and a little outward, its lower part forward and a little inward. To the 
upper three-fourths of this surface the Crureus is attached; the lower fourth is 
separated from the muscle by the intervention of the synovial membrane of the 
knee-joint and a bursa, and affords attachment to the Subcrureus to a small extent. 
External Surface.-The external surface includes the portion of bone between 
the external border and the outer lip of the linea aspera: it is continuous above 
with the outer surface of the great trochanter, below with the outer surface of 
the external condyle; to its upper three-fourths is attached the outer portion of 
the Crureus muscle. 
Internal Surface.-The internal surface includes the portion of bone between 
the internal border and the inner lip of the linea aspera; it is continuous above 
with the lower border of the neck, below with the inner side of the internal con- 
dyle: it is covered by the Vastus internus muscle. 
Lower Extremity.-The lower extremity, larger than the upper, is of a cuboid 
form, flattened from before backward, and divided into two large eminences, 
the condyles (condyli, from xwdoAo^, a knuckle), by an interval which presents a 
smooth depression in front called the trochlea (facies patellaris), and a notch of con- 
siderable size behind-the intercondyloid notch (fossa intercondyloidea). The exter- 
nal condyle (condylus lateralis) is the more prominent anteriorly, and is the broader 
both in the antero-posterior and transverse diameters. The internal condyle (con- 
dylus medians') is the narrower, longer, and more prominent inferiorly. This 
difference in the length of the two condyles is only observed when the bone is 
perpendicular and depends upon the obliquity of the thigh bones, in consequence 
of their separation above at the articulation with the pelvis. If the femur is 
held obliquely, the surfaces of the two condyles will be seen to be nearly hori- 226 
THE SKELETON 
zontal. The two condyles are directly continuous in front, and form a smooth, 
trochlear surface, the trochlea, which articulates with the patella. It presents 
a median groove, which extends downward and backward to the intercondyloid 
notch; and two lateral convexities, of which the external is the broader, more 
prominent, and prolonged farther upward upon the front of the outer condyle. 
The external border of this articular surface is also more prominent, and ascends 
higher than the internal one. The intercondyloid notch lodges the crucial liga- 
ments; it is bounded laterally by the opposed surfaces of the two condyles, and 
in front by the lower end of the shaft. Between the popliteal surface and the 
floor of the intercondyloid notch is an elevation (linea intercondyloidea), which 
affords attachment to the posterior ligament of the knee-joint. 
Outer or External Condyle (condylus lateralis).-1The outer surface of the external 
condyle presents, a little behind its centre, an eminence, the outer tuberosity (epi- 
condylus lateralis); it is less prominent than the inner tuberosity, and gives attach- 
ment to the external lateral ligaments of the knee. Immediately beneath it is a 
groove, the popliteal groove (sulcus popliteus), which commences at a depression a 
little behind the centre of the lower border of this surface: the front part of this 
depression gives origin to the Popliteus muscle, the tendon of which is lodged 
in the groove during flexion of the knee. The groove is smooth, covered with 
cartilage in the recent state, and runs upward and backward to the posterior 
extremity of the condyle. The inner surface of the outer condyle forms one of 
the lateral boundaries of the intercondyloid notch, and gives attachment, by its 
posterior part, to the anterior crucial ligament. The inferior surface is convex, 
smooth, and broader than that of the internal condyle. The posterior extremity 
is convex and smooth: just above and to the outer side of the articular surface 
is a depression for the tendon of the outer head of the Gastrocnemius, above 
which is the origin of the Plantaris. 
Inner or Internal Condyle (condylus medialis).-The inner surface of the inner 
condyle presents a convex eminence, the inner tuberosity (epicondylus medialis), 
rough for the attachment of the internal lateral ligament. The outer side of the 
inner condyle forms one of the lateral bound- 
aries of the intercondyloid notch, and gives 
attachment, by its anterior part, to the posterior 
crucial ligament. Its inferior or articular sur- 
face is convex, and presents a less extensive 
surface than the external condyle. Just above 
the articular surface of the condyle, behind, 
is a depression for the tendon of origin of the 
inner head of the Gastrocnemius. 
Structure.-The shaft of the femur is a 
cylinder of compact tissue, hollowed by a 
large medullary canal. The cylinder is of great 
thickness and density in the middle third of 
the shaft, where the bone is narrowest and the 
medullary canal well formed; but above and 
below this the cylinder gradually becomes 
thinner, owing to a separation of the layers of 
the bone into cancelli, which project into the 
medullary canal and finally obliterate it, so 
that the upper and lower ends of the shaft, and 
the articular extremities more especially, consist of cancellated tissue invested 
by a thin, compact layer. 
The arrangement of the cancelli in the ends of the femur is remarkable. In 
the upper end they are arranged in two sets. One, starting from the top of the 
Shaft. 
Tension 
planes. 
Pressure 
planes. 
Fig. 163.-Diagram showing the arrangement 
of the bone-fibres of the neck of the femur. THE FEMUR, OR THIGH BONE 
227 
head, the upper surface of the net k, and the great-trochanter, converge to the inner 
circumference of the shaft (Figs. 163 and 164); these are placed in the direction of 
greatest pressure, and serve to support the vertical weight of the body. The second 
set are planes of lamellae intersecting the former nearly at right angles, and are 
Fig. 164.-Right femur, upper extremity, ground frontal section, from in front. (Spalteholz.) 
situated in the line of the greatest tension-that is to say, along the lines in which 
the muscles and ligaments exert their traction. In the head of the bone these 
planes are arranged in a curved form, in order to strengthen the bone when exposed 
to pressure in all directions. In the midst of the cancellous tissue of the neck is 
a vertical plane of compact bone, the femoral spur (calcar j emorale}, which com- 228 
THE SKELETON 
inences at the point where the neck joins the shaft midway between the lesser 
trochanter and the internal border of the shaft of the bone, and extends in the 
direction of the digital fossa (Fig. 165). This materially strengthens this portion 
of the bone. Another point in connection with the structure of the neck of the 
femur requires mention, especially on account of its influence on the production 
of fracture in this situation. It will be noticed that a considerable portion of the 
great trochanter lies behind the level of the posterior surface of the neck; and if a 
section be made through the trochanter at this level, it will be seen that the pos- 
terior wall of the neck is prolonged into the trochanter. This prolongation is 
termed by Bigelow the true neck,1 and forms a thin, dense plate of bone, which 
passes beneath the posterior intertrochanteric ridge toward the outer surface of 
the bone. In the lower end the cancelli spring on all sides from the inner surface 
of the cylinder, and descend in a perpendicular direction to the articular surface, 
Appears at end 
of 1st year; 
joins shaft about 
18th year. 
Great trochanter. 
Appears at 4th 
year; joins shaft 
about 18th year. 
Digital fossa. 
Appears 13th-14th year ; 
joins shaft about 18th 
year. 
i Lesser 
trochanter. 
Calcar 
femorale. 
Appears at 
9th month' 
(foetal). 
I Joins shaft at 20th 
year. 
Lower extremity. 
Fig. 165.-Calcar femorale. 
Fig. 166.-Plan of the development of the femur. By 
five centres. 
the cancelli being strongest and having a more accurately perpendicular course 
above the condyles. In addition to this, however, horizontal planes of cancellous 
tissue are to be seen, so that the spongy tissue in this situation presents an appear- 
ance of being mapped out into a series of rectangular areas. 
Articulations.-With three bones: the os innominatum, tibia, and patella. 
Development (Fig. 166).-The femur is developed by five centres: one for the 
shaft, one for each extremity, and one for each trochanter. Of all the long bones, 
except the clavicle, it is the first to show traces of ossification: this commences in 
the shaft, at about the seventh week of foetal life, the centres of ossification in the 
epiphyses appearing in the following order: First, in the lower end of the bone, 
at the ninth month of fietal life2 (from this the condyles and tuberosities are 
1 Bigelow on the Hip, p. 121. 
2 This is said to be the only epiphysis in which ossification begins before birth; though according to some 
observers, the centre for the upper epiphysis of the tibia also appears before birth. THE FEMUR, OR THIGH BONE 
229 
formed); in the head at the end of the first year after birth; in the great tro- 
chanter, during the fourth year; and in the lesser trochanter, between the thir- 
teenth and fourteenth. The order in which the epiphyses are joined to the shaft 
is the reverse of that of their appearance: their junction does not commence until 
after puberty, the lesser trochanter being first joined, then the great, then the 
head, and, lastly, the inferior extremity (the first in which ossification commenced), 
which is not united until the twentieth year. 
Attachment of Muscles.-To twenty-three. To the great trochanter: the Glu- 
teus medius, Gluteus minimus, Pyriformis, Obturator interims, Obturator externus, 
Gemellus superior, Gemellus inferior, and Quadratus femoris. To the lesser 
trochanter: the Psoas magnus and the Iliacus below it. To the shaft: the Vastus 
externus, Gluteus maximus, short head of the Biceps, Vastus internus, Adductor 
magnus, Pectineus, Adductor brevis, Adductor longus, Crureus, and Subcrureus. 
To the condyles: the Gastrocnemius, Plantaris, and Popliteus. 
Surface Form.-The femur is covered with muscles, so that in fairly muscular subjects the 
shaft is not to be detected through its fleshy covering, and the only parts accessible to the touch 
are the outer surface of the great trochanter and the lower expanded end of the bone. The 
external surface of the great trochanter is to be felt, especially in certain positions of the limb. Its 
position is generally indicated by a depression, owing to the thickness of the Gluteus medius and 
minimus, which project above it. When, however, the thigh is flexed, and especially if crossed 
over the opposite one, the trochanter produces a blunt eminence on the surface. The upper 
border is about on a line with the spine of the os pubis, and its exact level is indicated by a 
line drawn from the anterior superior spinous process of the ilium, over the outer side of the 
hip, to the most prominent point of the tuberosity of the ischium. This is known as Nelaton's 
line. The outer and inner condyles of the lower extremity are easily to be felt. The outer one 
is more subcutaneous than the inner one and readily felt. The tuberosity on it is comparatively 
little developed, but can be more or less easily recognized. The inner condyle is more thickly 
covered, and this gives a general convex outline to this part, especially when the knee is flexed. 
The tuberosity on it is easily felt, and at the upper part of the condyle the sharp tubercle for the 
insertion of the tendon of the Adductor magnus can be recognized without difficulty. When 
the knee is flexed, and the patella situated in the interval between the condyles and the upper 
end of the tibia, a part of the trochlear surface of the femur can be made out above the patella. 
Surgical Anatomy.-There are one or two points about the ossification of the femur bear- 
ing on practice to which allusion must be made. It has been stated above that the lower end 
of the femur is the only epiphysis in which ossification has commenced at the time of birth. 
The presence of the ossific centre in newly born children found dead is, therefore, a proof 
that the child has arrived at the full period of utero-gestation, and is always relied upon in 
medico-legal investigations. The position of the epiphysial line should be carefully noted. It 
is on a level with the adductor tubercle, and the epiphysis does not, therefore, form the whole 
of the cartilage-clad portion of the lower end of the bone. It is essential to bear this point in 
mind in performing excision of the knee, since growth in length of the femur takes place chiefly 
from the lower epiphysis, and any interference with the epiphysial cartilage in a young child 
would involve such ultimate shortening of the limb, from want of growth, as to render it almost 
useless. Separation of the lower epiphysis may take place up to the age of twenty, at which 
time it becomes completely joined to the shaft of the bone; but, as a matter of fact, few cases 
occur after the age of sixteen or seventeen. The epiphysis of the head of the femur is of interest 
principally on account of its being the seat of origin of a large number of cases of tuberculous 
disease of the hip-joint. The disease commences in the majority of cases in the highly vascular 
and growing tissue in the neighborhood of the epiphysis, and from here extends into the joint. 
In the condition known as coxa vara the head of the femur falls to a lower level than normal. 
The angle between the neck and shaft is greatly diminished and may become a right angle or 
the head may actually descend to a lower level than that of the trochanter. The neck is also 
bent with a convexity forward; coxa vara is due to rickets. 
Fractures of the femur are divided, like those of the other long bones, into fractures of the 
upper end; of the shaft; and of the lower end. The fractures of the upper end may be classi- 
fied into (1) fracture of the neck; (2) fracture at the junction of the neck with the great trochanter; 
(3) fracture of the great trochanter; and (4) separation of the epiphysis, either of the head or 
of the great trochanter. The first of these, fracture of the neck, is usually termed intracapsular 
fracture, but this is scarcely a correct designation, as owing to the attachment of the capsular 
ligament, the fracture may be partly within and partly without the capsule, when the fracture 
occurs at the lower part of the neck. It generally occurs in old people, principally women, and 
usually from a very slight degree of indirect violence. Probably the main cause of the fracture 230 
THE SKELETON 
taking place in old people is in consequence of the degenerative changes which the bone has 
undergone. Merkel believes that it is mainly due to the absorption of the calcar femorale. 
These fractures are occasionally impacted. As a rule they unite by fibrous tissue, and frequently 
no union takes place, and the surfaces of the fracture become smooth and eburnated. The 
lack of reparative power in intracapsular fracture is due to lack of apposition of the fragments and 
diminution in the amount of blood sent to the smaller fragment. The head of the bone receives 
blood from the neck through the reflected portions of the capsule and through the Ligamentum 
teres. A fracture cuts off the supply by the neck and by the reflected portions of the capsule. 
Fractures at the junction of the neck with the great trochanter are usually termed extra- 
capsular, but this designation is also incorrect, as the fracture is partly within the capsule, 
owing to its attachment in front to the anterior intertrochanteric line, which is situated below 
the line of fracture. These fractures are produced by direct violence to the great trochanter, as 
from a blow or fall laterally on the hip. From the manner in which the accident is caused, the 
neck of the bone is driven into the trochanter, where it may remain impacted or the trochanter 
may be split up into two or more fragments, and thus no fixation takes place. 
Fractures of the great trochanter may be either 'oblique fracture through the trochanter 
major, without implicating the neck of the bone'5 (Astley Cooper), or separation of the great 
trochanter. Most of the recorded cases of this latter injury occurred in young persons, and 
were probably cases of separation of the epiphysis of the great trochanter. Separation of the 
epiphysis of the head of the femur has been said to occur, but has probably never been verified 
by post-mortem examination. 
Fractures of the shaft may occur at any part, but the most usual situation is at or near the 
centre of the bone. They may be caused by direct or indirect violence or by muscular action. 
Fractures of the upper third of the shaft are almost always the result of indirect violence, whilst 
those of the lower third are the result, for the most part, of direct violence. In the middle third 
fractures occur from both forms of injury in about equal proportions. Fractures of the shaft 
are generally oblique, but they may be transverse, longitudinal, or spiral. The transverse 
fracture occurs most frequently in children. The fractures of the lower end of the femur include 
transverse fracture above the condyles, the most common; and this may be complicated by a 
vertical fracture between the condyles, constituting the T-shaped fracture. In these cases the 
popliteal artery is in danger of being wounded. Oblique fracture, separating either the internal 
or external condyle, and a longitudinal incomplete fracture between the condyles, may also take 
place. 
The femur and also the bones of the leg are frequently the seat of acute osteomyelitis in young 
children. This is no doubt due to their greater exposure to injury, which is often the exciting 
cause of this disease. Tumors not unfrequently are found growing from the femur: the most 
common forms being sarcoma, which may grow either from the periosteum or from the medullary 
tissue within the interior of the bone; and exostosis, which is commonly found originating in 
the neighborhood of the epiphysial cartilage of the lower end. 
Genu varum is a form of bow-leg in which the tibia and femur are curved outward, the knees 
being widely separated. Both extremities are usually affected. In early life the disease is due 
to rickets. In elderly people it may be due to arthritis deformans. Genu valgum (knock-knee) 
is a condition in which the knees are close together, the feet are wide apart, and the internal 
lateral ligament of the knee-joint is stretched. It is due to excessive growth of the inner con- 
dyle of the femur, the shaft of the femur curving inward. It may be due to rickets, attitude of 
an occupation, or flat-foot, and one or both knees may be affected. 
THE LEG. 
The skeleton of the leg consists of three bones; the patella, a large sesamoid 
bone, placed in front of the knee; the tibia; and the fibula. 
The Patella, or Knee-cap (Figs. 167, 168). 
The patella {patella, a small pan), the knee-cap or knee-pan, is a flat, triangular 
bone, situated at the anterior part of the knee-joint. It is usually regarded as a 
sesamoid bone, developed in the tendon of the Quadriceps extensor. It resembles 
these bones (1) in its being developed in a tendon; (2) in its centre of ossification 
presenting a knotty or tuberculated outline; (3) in its structure being composed 
mainly of dense cancellous tissue, as in the other sesamoid bones. It serves to 
protect the front of the joint, and increases the leverage of the Quadriceps extensor 
by making it act at a greater angle. It presents an anterior and a posterior sur- 
face, three borders, and an apex. THE PATELLA, OB KNEE-CAP 
231 
Surfaces. Anterior Surface.-The anterior surface is convex, perforated by 
small apertures, for the passage of nutrient vessels, and marked by numerous 
rough, longitudinal striae. This surface is covered, in the recent state, by an 
expansion from the tendon of 
the Quadriceps extensor, which 
is continuous below with the 
superficial fibres of the liga- 
mentum patellae. It is sepa- 
rated from the integument by 
a bursa. 
Posterior Surface.-The pos- 
terior surface presents a 
smooth, oval-shaped, articular 
surface (jacies articular is), cov- 
ered with cartilage in the re- 
cent state, and divided into two facets by a vertical ridge, which descends from 
the superior border toward the inferior angle of the bone. The ridge corresponds 
to the groove on the trochlear surface of the femur, and the two facets to the 
articular surfaces of the two condyles; the outer facet, for articulation with the 
outer condyle, being the broader and deeper. This character serves to indicate 
the side to which the bone belongs. Below the articular surface is a rough, convex, 
non-articular depression, the lower half of which gives attachment to the liga- 
mentum patellie, the upper half being separated from the head of the tibia by 
adipose tissue. 
Borders. Superior Border.-The superior border (basis patella?) is thick, and 
sloped from behind, downward and forward: it gives attachment to that portion 
of the Quadriceps extensor which is derived from the Rectus and Crureus muscles. 
Lateral Borders.-The lateral borders are thinner, converging below. They 
give attachment to that portion of the Quadriceps extensor derived from the 
external and internal Vasti muscles. 
The Apex (apex patellae).-The apex is pointed, and gives attachment to the 
ligamentum patellae. 
Structure.-It consists of a nearly uniform, dense cancellous tissue covered 
by a thin compact lamina. The cancelli immediately beneath the anterior surface 
are arranged parallel with it. In the rest of the bone they radiate from the pos- 
terior articular surface toward the other parts of the bone. 
Development.-By a single centre, which makes its appearance, according to 
B^clard, about the third year. In two instances Mr. Pick has seen this bone car- 
tilaginous throughout, at a much later period (six years). More rarely, the bone is 
developed by two centres, placed side by side. Ossification is completed about 
the age of puberty. 
Articulations.-With the two condyles of the femur. 
Attachment of Muscles.-To four: the Rectus, Crureus, Vastus internus, and 
Vastus externus. These muscles, joined at their insertion, constitute the Quadri- 
ceps extensor cruris. 
Fig. 167.-Right patella. 
Anterior surface. 
Fig. 168.-Right patella. 
Posterior surface. 
Surface Form.-The external surface of the patella can be seen and felt in front of the 
knee. In the extended position of the limb the internal border is a little more prominent than 
the outer, and if the Quadriceps extensor is relaxed the bone can be moved from side to side and 
appears to be loosely fixed. If the joint is flexed, the patella recedes into the hollow between the 
condyles of the femur and the upper end of the tibia, and becomes firmly fixed against the femur. 
Surgical Anatomy.-The main surgical interest about the patella is in connection with 
fractures, which are of common occurrence. They may be produced by muscular action; that 
is to say, by violent contraction of the Quadriceps extensor while the limb is in a position of 
semi-flexion, so that the bone is snapped across the condyles; or by direct violence, such as 232 
THE SKELETON 
Head. 
Head. 
Styloid process.' 
•Styloid process. 
EXTERNAL' 
LATERAL 
LIGAMENT. 
Fibula. 
Tibia. 
Tibia. 
Fibula. 
Internal malleolus. 
External malleolus. 
Fig. 169.-Bones of the right leg. Anterior surface. 
Fig. 170.-Bones of the right leg. Posterior surface. THE TIBIA, OR SHIN BONE 
233 
falls on the knee. Most fractures are due to muscular action; in fact, the patella is more often 
broken by muscular action than is any other bone. In fractures by muscular action the line of 
fracture is transverse. In fractures by direct force the line of fractuure may be oblique, longi- 
tudinal, stellate, or the bone variously comminuted. The principal interest in these cases 
attaches to their treatmennt. Owing to the wide separation of the fragments, and the diffi- 
culty there is in maintaining them in apposition, union takes place by fibrous tissue, and this 
may subsequently stretch, producing wide separation of the fragments and permanent lame- 
ness. Various plans, including opening the joint and suturing the fragments, have been advo- 
cated for overcoming this difficulty. In many cases a portion of fascia or capsule gets between 
the fragments. In such a condition operation is necessary. 
In the larger number of cases of fracture of the patella the knee-joint is involved, the car- 
tilage which covers its posterior surface being torn, the synovial membrane lacerated, the lateral 
fibrous expansions ruptured, and the patellar bursa torn open. In cases of fracture from 
direct violence, however, this need not necessarily happen, the lesion may involve only the 
superficial part of the bone; and, as Morris has pointed out, it is an anatomical possibility, in 
complete fracture, if the lesion involve only the lower and non-articular part of the bone, for 
it to take place without injury to the synovial membrane. 
The Tibia, or Shin Bone (Figs. 169, 170). 
The tibia (tibia, a flute or pipe) is situated at the front and inner side of the 
leg, and, excepting the femur, is the longest and largest bone in the skeleton. It 
is prismoid in form, expanded above, where it enters into the knee-joint, more 
slightly enlarged below. In the male its direction is vertical and parallel with 
the bone of the opposite side; but in the female it has a slightly oblique direction 
downward and outward, to compensate for the oblique direction of the femur 
inward. It presents for examination a shaft and two extremities. 
Upper Extremity.-The upper extremity, or head, is large, and expanded 
on each side into two lateral eminences, the internal and external tuberosities 
(condylus medialis and condylus lateralis). Superiorly, each tuberosity presents 
a smooth, concave surface (facies articularis superior), which articulates with 
ATTACHMENT OF POSTERIOR 
EXTREMITY OF EXTERNAL 
SEMILUNAR CARTILAGE 
ORIGIN OF POSTERIOR 
OR INTERNAL 
CRUCIAL LIGAMENT 
ATTACHMENT OF POSTERIOR 
EXTREMITY OF INTERNAL 
SEMILUNAR CARTILAGE 
ATTACHMENT OF ANTERIOR' 
EXTREMITY OF EXTERNAL 
SEMILUNAR CARTILAGE 
ORIGIN OF ANTE- 
RIOR OR EXTERNAL 
CRUCIAL LIGAMENT 
'ATTACHMENT OF ANTERIOR 
EXTREMITY OF INTERNAL 
SEMILUNAR CARTILAGE 
Fig. 171.-Upper articular surface of the tibia, showing the attachments of the ligaments. 
(Poirier and Charpy.) 
a condyle of the femur. The internal, articular surface is longer, deeper, and 
narrower than the external, oval from before backward, to articulate with the in- 
ternal condyle; the external one is broader and more circular, concave from side 
to side, but slightly convex from before backward, especially at its posterior part, 
where it is prolonged on to the posterior surface for a short distance, to articulate 
with the external condyle. Between the two articular surfaces, and nearer the pos- 
terior than the anterior aspect of the bone, is an eminence, the spinous process 
of the tibia (eminentia intercondyloided)-, surmounted by a prominent tubercle on 
each side (the tuberculum intercondyloideum mediate and the tuberculum inter- 
condyloideum laterale), on to the lateral aspect of which the facets just described 
are prolonged; in front and behind the spinous process is a rough depression 234 
THE SKELETON 
(fossa intercondyloidea anterior and the fossa intercondyloidea posterior") for the 
attachment of the anterior and posterior crucial ligaments and the semilunar 
fibro-cartilages (Fig. 171). 
The anterior surfaces of the tuberosities are continuous with one another, form- 
ing a single large surface, which is somewhat flattened: it is triangular, broad 
above, and perforated by large vascular foramina; narrow below, where it ter- 
minates in a prominent oblong elevation of large size, the tubercle of the tibia 
(tuberositas tibce); the lower half of this tubercle is rough, for the attachment of 
the ligamentum patella?; the upper half presents a smooth facet supporting, in the 
recent state, a bursa which separates the ligament from the bone. Posteriorly the 
tuberosities are separated from each other by a shallow depression, the popliteal 
notch (incisura poplitea), which gives attachment to part of the posterior crucial 
ligament and part of the posterior ligament of the knee-joint. The inner tuberosity 
presents posteriorly a deep transverse groove, for the insertion of one of the fas- 
ciculi of the tendon of the Semi-membranosus. Its lateral surface is convex, 
rough, and prominent, and gives attachment to the internal lateral ligament. The 
outer tuberosity presents posteriorly a flat articular facet (facies articular is fibularis"), 
nearly circular in form, directed downward, backward, and outward, for articu- 
lation with the fibula. Its lateral surface is convex and rough, more prominent 
in front than the internal, and presents a prominent rough eminence, situated on 
a level with the upper border of the tubercle of the tibia at the junction of its 
anterior and outer surfaces, for the attachment of the ilio-tibial band. Just below 
this the Extensor longus digitorum and a slip from the Biceps are attached. The 
infraglenoid margin (margo infraglenoidalis) is at the outer edge of the superior 
articular surface. From this point the bone rapidly narrows distally. 
Shaft of the Tibia (corpus tibice).-The shaft of the tibia is of a triangular 
prismoid form, broad above, gradually decreasing in size to its most slender part, 
at the commencement of its lower fourth, where fracture most frequently occurs; 
it then enlarges again toward its lower extremity. It presents for examination 
three borders and three surfaces. 
Anterior Border.- The anterior border, the most prominent of the three, is 
called the crest of the tibia (crista anterior"), or, in popular language, the shin; it 
commences above at the tubercle, and terminates below at the anterior margin 
of the inner malleolus. This border is very prominent in the upper two-thirds of 
its extent, smooth and rounded below. It presents a very flexuous course, being 
usually curved outward above and inward below; it gives attachment to the 
deep fascia of the leg. 
Internal Border (margo medialis").-The internal border is smooth and rounded 
above and below, but more prominent in the centre; it commences at the back 
part of the inner tuberosity, and terminates at the posterior border of the inter- 
nal malleolus; its upper part gives attachment to the internal lateral ligament of 
the knee to the extent of about two inches, and to some fibres of the Popliteus 
muscle, and its middle third to some fibres of the Soleus and Flexor longus 
digitorum muscles. 
External Border (crista interossea).-The external border, or interosseous ridge, 
is thin and prominent, especially its central part, and gives attachment to the 
interosseous membrane; it commences above in front of the fibular articular facet, 
and bifurcates below, to form the boundaries of a triangular rough surface, for 
the attachment of the interosseous ligament connecting the tibia and fibula. 
Internal Surface (facies medialis").-The internal surface is smooth, convex, 
and broader above than below; its upper third, directed forward and inward, is 
covered by the aponeurosis derived from the tendon of the Sartorius, and by the 
tendons of the Gracilis and Semitendinosus, all of which are inserted nearly as 
far forward as the anterior border; in the rest of its extent it is subcutaneous. THE TIBIA, OR SHIN BONE 
235 
External Surface (facies lateralis).-The external surface is narrower than the 
internal; its upper two-thirds presents a shallow groove for the attachment of 
the Tibialis anticus muscle; its lower third is smooth, convex, curves gradually 
forward to the anterior aspect of the bone, and is covered from within outward by 
the tendons of the following muscles: Tibialis anticus, Extensor proprius hallucis, 
Extensor longus digitorum. 
Posterior Surface (facies posterior).-The posterior surface (Fig. 170) presents, 
at its upper part, a prominent ridge, the popliteal line or the oblique line of the 
tibia (linea poplitea), which extends from the back part of the articular facet 
for the fibula obliquely downward, to the internal border, at the junction of 
its upper and middle thirds. It marks the lower limit for the insertion of the 
Popliteus muscle, and serves for the attachment of the popliteal fascia and part 
of the Soleus, Flexor longus digitorum, and Tibialis posticus muscles; the tri- 
angular concave surface, above and to the inner side of this line, gives attach- 
ment to the Popliteus muscle. The middle third of the posterior surface is 
divided by a vertical ridge into two lateral halves: the ridge is well marked at 
its commencement at the oblique line, but becomes gradually indistinct below; 
the inner and broader half gives attachment to the Flexor longus digitorum, the 
outer and narrower to part of the Tibialis posticus. The remaining part of the 
bone presents a smooth surface covered by the Tibialis posticus, Flexor longus 
digitorum, and Flexor longus hallucis muscles. Immediately below the oblique 
line is the nutritive foramen (foramen nutricium), which is large and directed 
obliquely downward. It is the opening of the nutrient canal, which is directed 
toward the periphery. 
Lower Extremity.-The lower extremity, much smaller than the upper, 
presents five surfaces; it is prolonged downward, on its inner side, to a strong 
process, the internal malleolus (malleolus medial is). 
Inferior Surface (facies articularis inferior).-The inferior surface of the bone 
is quadrilateral, and smooth for articulation with the astragalus. This surface 
is concave from before backward, and broader in front than behind. It is trav- 
ersed from before backward by a slight elevation, separating two lateral depres- 
sions. It is narrow internally, where the articular surface becomes continuous 
with that on the inner malleolus (facies articularis malleolaris). 
Anterior Surface.-The anterior surface of the lower extremity is smooth and 
rounded above, and covered by the tendons of the Extensor muscles of the toes; 
its lower margin presents a rough transverse depression, for the attachment of 
the anterior ligament of the ankle-joint. 
Posterior Surface.-The posterior surface presents a superficial groove directed 
obliquely downward and inward, continuous with a similar groove on the posterior 
surface of the astragalus, and serving for the passage of the tendon of the Flexor 
longus hallucis. 
External Surface.-The external surface presents a triangular rough depression 
for the attachment of the interior interosseous ligament, connecting it with the 
fibula; the lower part of this depression, the fibular notch (incisura fibularis), is 
smooth, covered with cartilage in the recent state, and articulates with the fibula. 
This surface is bounded by two prominent borders, continuous above with the 
interosseous ridge; they afford attachment to the anterior inferior and posterior 
inferior tibio-fibular ligaments. 
Internal Surface.-The internal surface of the lower extremity is prolonged 
downward to form a strong pyramidal process, flattened from without inward- 
the internal malleolus (malleolus medialis). The inner surface of this process is 
convex and subcutaneous; its outer surface is smooth and slightly concave, and 
articulates with the astragalus; its anterior border is rough, for the attachment of 
the anterior fibres of the internal lateral or Deltoid ligament; its posterior border 236 
THE SKELETON 
presents a broad and deep groove {sulcus malleolar is), directed obliquely down- 
ward and inward, which is occasionally double: this groove transmits the tendons 
of the Tibialis posticus and Flexor longus digitorum muscles. The summit of the 
internal malleolus is marked by a rough depression behind, for the attachment of 
the internal lateral ligament of the ankle-joint. 
Structure.-Like that of the other long bones. At the junction of the middle 
and lower third, where the bone is smallest, the wall of the shaft is thicker than 
in other parts, in order to compensate for the smallness of the calibre of the bone. 
Development.-By three centres (Fig. 172): one for the shaft and one for 
each extremity. Ossification commences in the centre of the shaft about the 
seventh week, and gradually extends to- 
ward either extremity. The centre for 
the upper epiphysis appears before or 
shortly after birth; it is flattened in form, 
and has a thin, tongue-shaped process in 
front which forms the tubercle. That 
for the lower epiphysis appears in the 
second year. The lower epiphysis joins 
the shaft at about the eighteenth, and 
the upper one about the twentieth year. 
Two additional centres occasionally exist 
-one for the tongue-shaped process of 
the upper epiphysis, which forms the 
tubercle, and one for the inner malleolus. 
Articulations.-With three bones: the 
femur, fibula, and astragalus. 
Attachment of Muscles.-To twelve: 
to the inner tuberosity, the Semimem- 
branosus; to the outer tuberosity, the 
Tibialis anticus and Extensor longus digi- 
torum and Biceps; to the shaft, its in- 
ternal surface, the Sartorius, Gracilis, and 
Semitendinosus; to its external surface, 
the Tibialis anticus; to its posterior sur- 
face, the Popliteus, Soleus, Flexor longus 
digitorum, and Tibialis posticus; to the 
tubercle, the ligamentum patellae, by which the Quadriceps extensor muscle is 
inserted into the tibia. In addition to these muscles, the Tensor fasciae femoris is 
inserted indirectly into the tibia, through the ilio-tibial band, and the Peroneus 
longus occasionally derives a few fibres of origin from the outer tuberosity. 
Upper extremity. 
Appears at_ 
birth. 
.Joins shaft about 
20th year. 
Appears at 2nd. 
year. 
Joins shaft about 
18th year. 
Lower extremity. 
Fig. 172.-Plan of the development of the tibia. 
By three centres. 
Surface Form.-A considerable portion of the tibia is subcutaneous and easily to be felt. 
At the upper extremity the tuberosities are to be recognized just below the knee. The internal 
one is broad and smooth, and merges into the subcutaneous surface of the shaft below. The 
external one is narrower and more prominent, and on it, about midway between the apex of the 
patella and the head of the fibula, may be felt a prominent tubercle for the insertion of the ilio- 
tibial band. In front of the upper end of the bone, between the tuberosities, is the tubercle of 
the tibia, forming an oval eminence which is continuous below with the anterior border or crest 
of the bone. This border can be felt, forming the prominence of the shin, in the upper two- 
thirds of its extent as a sharp and flexuous ridge, curved outward above and inward below. In 
the lower third of the leg the border disappears, and the bone is concealed by the tendons of 
the muscles on the front of the leg. Internal to the anterior border is to be felt the broad 
internal surface of the tibia, slightly encroached upon by the muscles in front and behind. It 
commences above at the wide expanded inner tuberosity, and terminates below at the internal 
malleolus. The internal malleolus is a broad prominence situated on a higher level and some- 
what farther forward than the external malleolus. It overhangs the inner border of the arch 
of the foot. Its anterior border is nearly straight; its posterior border presents a sharp edge 
which forms the inner margin of the groove for the tendon of the Tibialis posticus muscle. THE FIBULA, OR CALF BONE 
237 
The Fibula, or Calf Bone (Figs. 169, 170). 
The fibula (fibula, a clasp) is situated at the outer side of the leg. It is the 
smaller of the two bones, and, in proportion to its length, the most slender of all 
the long bones; it is placed on the outer side of the tibia, with which it is con- 
nected above and below. Its upper extremity is small, placed toward the back of 
the head of the tibia and below the level of the knee-joint, and excluded from its 
formation; the lower extremity inclines a little forward, so as to be on a plane 
anterior to that of the upper end, projects below the tibia, and forms the outer 
ankle. It presents for examination a shaft and two extremities. 
Upper Extremity.-The upper extremity, or head (capitulum fibulae), is of 
an irregular quadrate form, presenting above a flattened articular facet, directed 
upward, forward, and inward, for articulation with a corresponding facet on the 
external tuberosity of the tibia. On the outer side is a thick and rough promi- 
nence, continued behind into a pointed eminence, the styloid process of the fibula 
(apex capituli fibulae), which projects upward from the posterior part of the 
head. The prominence gives attachment to the tendon of the Biceps muscle 
and to the long external lateral ligament of the knee, the ligament dividing the 
tendon into two parts. The summit of the styloid process gives attachment to 
the short external lateral ligament. The remaining part of the circumference of the 
head is rough, for the attachment of muscles and ligaments. It presents in front 
a tubercle for the origin of the upper and anterior part of the Peroneus longus, and 
the adjacent surface gives attachment to the anterior superior tibio-fibular liga- 
ment; and behind, another tubercle for the attachment of the posterior superior 
tibio-fibular ligament and the upper fibres of the Soleus muscle. 
Shaft of the Fibula (corpus fibulae).-The shaft presents four borders- 
the antero-external, the antero-internal, the postero-external, and the postero- 
internal; and four surfaces-anterior, posterior, internal, and external. 
Antero-external Border (crista anterior) .-The antero-external border commences 
above in front of the head, runs vertically downward to a little below the middle of 
the bone, and then, curving somewhat outward, bifurcates so as to embrace the 
triangular subcutaneous surface immediately above the outer surface of the exter- 
nal malleolus. This border gives attachment to an intermuscular septum, which 
separates the extensor muscles on the anterior surface of the leg from the Peroneus 
longus and brevis muscles on the outer surface. 
Antero-internal Border (crista interossea).-The antero-internal border, or inter- 
osseous ridge, is situated close to the inner side of the preceding, and runs nearly 
parallel with it in the upper third of its extent, but diverges from it so as to 
include a broader space in the lower two-thirds. It commences above, just 
beneath the head of the bone (sometimes it is quite indistinct for about an 
inch below the head), and terminates below at the apex of a rough triangular 
surface immediately above the articular facet of the external malleolus. It serves 
for the attachment of the interosseous membrane, which separates the extensor 
muscles in front from the flexor muscles behind. 
Postero-external Border (crista lateralis).-The postero-external border is promi- 
nent; it commences above at the base of the styloid process, and terminates below 
in the posterior border of the outer malleolus. It is directed outward above, back- 
ward in the middle of its course, backward and a little inward below, and gives 
attachment to an aponeurosis which separates the Peronei muscles on the outer 
surface of the shaft from the flexor muscles on its posterior surface. 
Postero-intemal Border (crista medialis).-The postero-internal border, some- 
times called the oblique line, commences above at the inner side of the head, 
and terminates by becoming continuous with the antero-internal border or inter- 238 
THE SKELETON 
osseous ridge at the lower fourth of the bone. It is well marked and promi- 
nent at the upper and middle parts of the bone. It gives attachment to an 
aponeurosis which separates the Tibialis posticus from the Soleus above and the 
Flexor longus hallucis below. 
Anterior Surface (facies anterior).-The anterior surface is the interval between 
the antero-external and antero-internal borders. It is extremely narrow and flat 
in the upper third of its extent; broader and grooved longitudinally in its lower 
third; it serves for the attachment of three muscles, the Extensor longus digitorum, 
Peroneus tertius, and Extensor proprius hallucis. 
External Surface (facies lateralis).-The external surface is the space between 
the antero-external and postero-external borders. It is much broader than the 
preceding, and often deeply grooved, is directed outward in the upper two-thirds 
of its course, backward in the lower third, where it is continuous with the poste- 
rior border of the external malleolus. This surface is completely occupied by 
the Peroneus longus and brevis muscles. 
Internal Surface (facies medialis).-The internal surface is the interval included 
between the antero-internal and the postero-internal borders. It is directed 
inward, and is grooved for the attachment of the Tibialis posticus muscle. 
Posterior Surface (facies posterior).-The posterior surface is the space included 
between the postero-external and the postero-internal borders, it is continuous 
below with the rough triangular surface above the articular facet of the outer 
malleolus; it is directed backward above, backward and inward at its middle, 
directly inward below. Its upper third is rough, for the attachment of the Soleus 
muscle; its lower part presents a triangular rough surface, connected to the tibia 
by a strong interosseous ligament, and between these two points the entire surface 
is covered by the fibres of origin of the Flexor longus hallucis muscle. At about 
the middle of this surface is the nutrient foramen (foramen nutricium). It opens 
into the nutrient canal (canalis nutricius), which is directed downward. 
Lower Extremity.-The lower extremity, or external malleolus (malleolus 
lateralis), is of a pyramidal form, somewhat flattened from without inward, and 
is longer, and descends lower than the internal malleolus. Its external surface is 
convex, subcutaneous, and continuous with the triangular (also subcutaneous) 
surface on the outer side of the shaft. The internal surface presents in front a 
smooth triangular facet (facies articularis malleoli), broader above than below, and 
convex from above downward, which articulates with a corresponding surface on 
the outer side of the astragalus. Behind and beneath the articular surface is a 
rough depression which gives attachment to the posterior fasciculus of the external 
lateral ligament of the ankle. The anterior border is thick and rough, and marked 
below by a depression for the attachment of the anterior fasciculus of the external 
lateral ligament. The posterior border is broad and marked by a shallow groove 
(sulcus malleolaris), for the passage of the tendons of the Peroneus longus and 
brevis muscles. The summit is rounded, and gives attachment to the middle 
fasciculus of the external lateral ligament. 
In order to distinguish the side to which the bone belongs, hold it with the 
lower extremity downward and the broad groove for the Peronei tendons back- 
ward-i. e., toward the holder; the triangular subcutaneous surface will then be 
directed to the side to which the bone belongs. 
Articulations.-With two bones: the tibia and astragalus. 
Development.-By three centres (Fig. 173): one for the shaft, and one for 
each extremity. Ossification commences in the shaft about the eighth week of 
foetal life, a little later than in the tibia, and extends gradually toward the extrem- 
ities. At birth both ends are cartilaginous. Ossification commences in the lower 
end in the second year, and in the upper one about the fourth year. The lower 
epiphysis, the first in which ossification commences, becomes united to the shaft THE FOOT 
239 
about the twentieth year; the upper epiphysis joins about the twenty-fifth year. 
Ossification appearing first in the lower epiphysis is contrary to the rule which 
prevails with regard to the commencement of ossification in epiphyses-viz., 
that epiphysis toward which the nutrient artery is 
directed commences to ossify last; but it follows the 
rule which prevails with regard to the union of epi- 
physes, by uniting first. 
Attachment of Muscles.-To nine: to the head, 
the Biceps, Soleus, and Peroneus longus; to the shaft, 
its anterior surface, the Extensor longus digitorum, 
Peroneus tertius, and Extensor proprius hallucis; to 
the internal surface, the Tibialis posticus; to the 
posterior surface, the Soleus and Flexor longus 
hallucis; to the external surface, the Peroneus longus 
and brevis. 
Upper extremity. 
Appears about 
4th year. 
Unites about 
' 25th year. 
Surface Form.-The only parts of the fibula which are to 
be felt are the head and the lower part of the external surface 
of the shaft and the external malleolus. The head is to be 
seen and felt behind and to the outer side of the outer tuber- 
osity of the tibia. It presents a small, prominent triangular 
eminence slightly above the level of the tubercle of the tibia. 
The external malleolus presents a narrow elongated promi- 
nence, situated on a plane posterior to the internal malleolus 
and reaching to a lower level. From it may be traced the 
lower third or half of the external surface of the shaft of the 
bone in the interval between the Peroneus tertius in front and 
the other two Peronei tendons behind. 
Surgical Anatomy.-In fractures of the bones of the leg both 
bones are usually fractured, but either bone may be broken 
separately, the fibula more frequently than the tibia. Fracture 
of both bones may be caused either by direct or indirect violence. When it occurs from indirect 
force, the fracture in the tibia is usually at the junction of the middle and lower third of the bone. 
Many causes conduce to render this the weakest part of the bone. The fracture of the fibula 
is usually at rather a higher level. These fractures present great variety, both as regards 
their direction and condition. They may be oblique, transverse, longitudinal, or spiral. When 
oblique, they are usually the result of indirect violence, and the direction of the fracture is from 
behind, downward, forward, and inward in many cases, but may be downward and outward 
or downward and backward. When transverse, the fracture is often at the upper part of the 
bone, and is the result of direct violence. The spiral fracture usually commences as a vertical 
fissure, involving the ankle-joint, and is associated with fracture of the fibula higher up. It is 
the result of torsion, from twisting of the body whilst the foot is fixed. 
Fractures of the tibia alone are almost always the result of direct violence, except where the 
malleolus is broken off by twists of the foot. Fractures of the fibula alone may arise from indi- 
rect or direct force, those of the lower end being usually the result of the former, and those 
higher up being caused by a direct blow on the part. 
The tibia and fibula, like the femur, are frequently the seat of acute osteomyelitis. Tuberculous 
abscess is more frequently met with in the cancellous tissue of the head and lower end of the 
tibia than in any other bone of the body. The abscess is of small size, very chronic, and prob- 
ably the result of tuberculous osteitis in the highly vascular growing tissue at the end of the shaft 
near the epiphysial cartilage in the young subject. Such an abscess in bone is called Brodie's 
abscess. 
The tibia is the bone which is most frequently and most extensively distorted in rickets. It 
gives way at the junction of the middle and lower third, its weakest part, and presents a curve 
forward and outward. Bow-leg is due to outward curvature of the femur, tibia, and fibula, 
the bend being about the junction of the shafts and lower extremities. 
Unites about 
20th year. 
Appears at 
2nd year. 
Fig. 173.-Plan of the development 
of the fibula. By three centres. 
Lower extremity. 
THE FOOT (Figs. 174, 175). 
The skeleton of the foot consists of three divisions: the tarsus, metatarsus, and 
phalanges. 240 
THE SKELETON 
, Groove for tendon of 
FLEXOR LONQUS HALLUCIS. 
Groove for peroneus lonqus.. 
Groove for peroneus brevis.' 
Tarsus. 
PERONEUS TERTIUS. 
PERONEUS BREVIS. 
Metatarsus. 
Innermost tendon of 
EXTENSOR BREVIS DlGITORUM. 
Phalanges. 
EXTENSOR LONQUS HALLUCIS. 
Fig. 174.-Bones of the right foot. Dorsal surface. THE FOOT 
241 
ABDUCTOR HALLUCIS.' 
OUTER HEAD OF ACCESSORIUS. 
,FLEXOR BREVIS HALLUCIS. 
Tubercle of, 
navicular. I 
TIBIALIS ANTIOUS.' 
FLEXOR BREVIS 
and ABDUCTOR 
MINIMI DIGITI. 
Two 
sesamoid- 
bones. 
-FLEXOR BREVIS DIGITORUM. 
,FLEXOR LONGUS DIGITORUM. 
Fig. 175.-Bones of the right foot. Plantar surface. 242 
THE SKELETON 
The Tarsus (Ossa Tarsi) 
The bones of the tarsus are seven in number-viz., the calcaneus or os calcis, 
astragalus, cuboid, scaphoid, internal, middle, and external cuneiform. 
The Calcaneus, or Heel Bone (Fig. 176).-It is also called the os calcis. The 
name is derived from calx, the heel. The heel bone is the largest and strongest of 
the tarsal bones. It is irregularly cuboidal in form, having its long axis directed for- 
A 
Peroneal tubercle. 
Groove for 
Peroneus brevis. 
Groove for 
Peroneus longus. 
Tubercle for ext. lat. lig. 
For tendo 
Achillis. 
B 
For astragalus. 
Sustentaculum 
tali. 
For cuboid. 
Groove for Flex, 
long, hallucis. 
Fig. 176.-The left os calcis. A. Postero-external view. B. Antero-internal view. 
ward and outward. It is situated at the lower and back hart of the foot, serving to 
transmit the weight of the body to the ground, and forming a strong lever for the 
muscles of the calf. It is composed of a body (corpus calcanei), an anterior extremity 
or greater process, and a posterior extremity or tuberosity (tuber calcanei). It pre- 
sents for examination six surfaces: superior, inferior, external, internal, anterior, 
and posterior. 
Superior Surface.-The superior surface is formed behind by the upper aspect 
of that part of the os calcis which projects backward to form the heel. It varies 
in length in different individuals; is convex from side to side, concave from before 
backward, and corresponds above to a mass of adipose substance placed in 
front of the tendo Achillis. In the middle of the superior surface are two (some- 
times three) articular facets, separated by a broad shallow groove (sulcus cal- 
canei), which is directed obliquely forward and outward, and is rough for the 
attachment of the interosseous ligament connecting the astragalus and os calcis. 
When the calcaneus is in contact with the astragalus this groove is converted into 
a canal (sinus tarsi). Of the articular surfaces, the external or posterior articular 
surface (facies articularis calcanea posterior) is the larger, and is situated on the body THE TARSUS 
243 
of the bone: it is of an oblong form, wider behind than in front, and convex from 
before backward. The internal or anterior articular surface is usually divided into 
two facets. The anterior facet is the facies articularis calcanea anterior, and it 
supports the head of the astragalus. The more posteriorly situated facet is the 
jacies articularis calcanea media. It articulates with the middle facet on the 
under surface of the astragalus. The internal articular surface is supported on 
a projecting process of bone, called the lesser process of the calcaneus (susten- 
taculum tali); it is also oblong, concave longitudinally, and sometimes subdivided 
into two parts, which differ in size and shape. More anteriorly is seen the upper 
surface of the greater process of the calcaneus, marked by a rough depression 
for the attachment of numerous ligaments, and a tubercle for the origin of the 
Extensor brevis digitorum muscle. 
Inferior Surface.-The inferior surface is narrow, rough, uneven, wider behind 
than in front and convex from side to side, it is bounded posteriorly by two tuber- 
cles separated by a rough depression; the external tubercle (processus lateralis tuberis 
calcanei), small, prominent, and rounded, gives attachment to part of the Abductor 
minimi digiti: the internal tubercle (processus medialis tuberis calcanei), broader 
and larger, for the support of the heel, gives attachment, by its prominent inner 
margin, to the Abductor hallucis, and in front to the Flexor brevis digitorum 
muscles and plantar fascia; the depression between the tubercles gives attach- 
ment to the Abductor minimi digiti. The rough surface in front of the tubercles 
gives attachment to the long plantar ligament and to the outer head of the Flexor 
accessorius muscle; while to a prominent tubercle nearer the anterior part of 
this surface, as well as to a transverse groove in front of it, is attached the 
short plantar ligament. 
External Surface.-The external surface is broad, flat, and almost subcutaneous; 
it presents near its centre a tubercle, for the attachment of the middle fasciculus 
of the external lateral ligament. At its upper and anterior part this surface 
gives attachment to the external calcaneo-astragaloid ligament; and in front of 
the tubercle it presents a narrow surface marked by two oblique grooves, sepa- 
rated by an elevated ridge which varies much in size in different bones; it is 
named the peroneal spine or tubercle (processus trochlearis), and gives attachment 
to a fibrous process from the external annular ligament. The superior groove 
transmits the tendon of the Peroneus brevis; the inferior groove the tendon of 
the Peroneus longus. 
Internal Surface.-The internal surface is deeply concave; it is directed obliquely 
downward and forward, and serves for the transmission of the plantar vessels 
and nerves into the sole of the foot; it affords attachment to part of the Flexor 
accessorius muscle. At its upper and fore part it presents an eminence of bone, 
the lesser process of the calcaneum (sustentaculum tali), which projects horizon- 
tally inward, and to it a slip of the tendon of the Tibialis posticus is attached. 
This process is concave above, and supports the anterior articular surface of 
the astragalus; below, it is grooved for the tendon of the Flexor longus hallucis. 
Its free margin is rough, for the attachment of part of the internal lateral liga- 
ment of the ankle-joint. 
Anterior Surface (facies articularis cuboidea).-The anterior surface, of a some- 
what triangular form, articulates with the cuboid. It is concave from above 
downward and outward, and convex in the opposite direction. Its inner border 
gives attachment to the inferior calcaneo-scaphoid ligament. 
Posterior Surface.-The posterior surface is rough, prominent, convex, and 
wider below than above. The posterior extremity is the projection of the heel. 
It is called the tuberosity (tuber calcanei). Its lower part is rough, for the attach- 
ment of the tendo Achillis and the tendon of the Plantaris muscle; its upper part 
is smooth, and is covered by a bursa which separates the tendons from the bone. THE SKELETON 
244 
Articulations.-With two bones: the astragalus and cuboid. 
Attachment of Muscles.-To eight: part of the Tibialis posticus, the tendo 
Achillis, Plantaris, Abductor hallucis, Abductor minimi digiti, Flexor brevis digi- 
torum, Flexor accessorius, and Extensor brevis digitorum. 
The Astragalus, or Ankle Bone (talus) (Fig. 177).-The astragalus (aarpdfaio', 
a die) is the largest of the tarsal bones, next to the os calcis. It occupies the 
middle and upper part of the tarsus, supporting the tibia above, articulating 
with the malleoli on either side, resting below upon the os calcis, and joined in 
front to the scaphoid. This bone may easily be recognized by its large rounded 
head, by the broad articular facet on its upper convex surface, and bv the two 
articular facets separated by a deep groove on its under concave surface. It 
For 
navicular. 
Neck. 
Sup. surface 
for tibia. 
For inner 
malleolus. 
For navicular. 
A 
B 
For ext. 
malleolus. 
For 
os calcis. 
For inferior 
calc, navic. lig. 
Groove for 
Flex. long. hall. 
Fig. 177.-The left astragalus. A. Superior and external view. B. Inferior and internal view. 
is divided into a body (corpus tali), which supports the trochlear surface; the 
head (caput tali), which is in front of the body; and the neck (collum tali), the 
constricted part between the head and body. The astragalus presents six 
surfaces for examination. 
Superior Surface.-The superior surface presents, behind, a broad smooth 
trochlear surface (trochlea tali) for articulation with the tibia. The trochlea is 
broader in front than behind, convex from before backward, slightly concave 
from side to side; in front of it is the upper surface of the neck of the 
astragalus, rough for the attachment of ligaments. 
Inferior Surface.-The inferior surface presents two articular facets separated 
by a deep groove (sulcus tali). The groove runs obliquely forward and outward, 
becoming gradually broader and deeper in front: it corresponds with a similar 
groove upon the upper surface of the calcaneus, and forms, when articulated with 
that bone, a canal (sinus tarsi), filled up in the recent state by the interosseous 
calcaneo-astragaloid ligament. Of the two articular facets, the posterior articular 
facet (facies articularis calcanea posterior) is the larger, of an oblong form and 
deeply concave from side to side; the anterior articular facet is shorter and nar- 
rower, of an elongated oval form, convex longitudinally, and often subdivided into 
two by an elevated ridge; of these, the posterior (facies articularis calcanea media) 
articulates with the lesser process of the os calcis; the anterior (facies articularis 
calcanea anterior), with the upper surface of the inferior calcaneo-scaphoid ligament. 
Internal Surface.-The internal surface presents at its upper part a pear-shaped 
articular facet (facies malleolaris medialis) for the inner malleolus, continuous 
above with the trochlear surface; below the articular surface is a rough 
depression, for the attachment of the deep portion of the internal lateral ligament. 
External Surface.-The external surface presents a large triangular facet (facies 
malleolaris lateralis), covered with cartilage and concave from above downward TILE TARSUS 
245 
for articulation with the external malleolus; it is called the external process (pro- 
cessus lateralis tali), and passes outward and downward from the triangular facet. 
The triangular facet is continuous above with the trochlear surface; and in front 
of it is a rough depression for the attachment of the anterior fasciculus of the 
external lateral ligament of the ankle-joint. 
Anterior Surface (facies articularis navicularis).-The anterior surface of the 
head of the astragalus is convex and rounded, smooth, of an oval form, and 
directed obliquely inward and downward; it articulates with the scaphoid. On 
its under and inner surface is a small facet, continuous in front with the articular 
surface of the head, and behind with the smaller facet for the os calcis. This 
rests on the inferior calcaneo-scaphoid ligament, being separated from it by the 
synovial membrane, which is prolonged from the anterior calcaneo-astragaloid 
joint to the astragalo-scaphoid joint. The head is surrounded by a constricted 
portion, the neck of the astragalus (collum tali). 
Posterior Surface.-The posterior surface is narrow, and traversed by a groove 
(sulcus m. flexoris hallucis longi), which runs obliquely downward and inward, 
and transmits the tendon of the Flexor longus hallucis, external to which is 
the prominent external tubercle (processus posterior tali), to which the posterior 
fasciculus of the external lateral ligament is attached. This tubercle is some- 
times separated from the rest of the astragalus, and is then known as the os 
trigonum. To the inner side of the groove is the less marked internal tubercle. 
To ascertain to which foot the bone belongs, hold it with the broad articular 
surface upward, and the rounded head forward; the lateral triangular articular 
surface for the external malleolus will then point to the side to which the bone 
belongs. 
Articulations.-With four bones: tibia, fibula, os calcis, and scaphoid. 
The Cuboid (os cuboideum) (Fig. 178).-The cuboid, from xuf^o^, a cube; 
eFJoC, like, is placed on the outer side of the foot, in front of the os calcis, and 
For ext. 
cuneiform. 
For fourth 
metatarsal. 
Occasional facet, 
for navicular. 
B 
A 
Groove for 
Peroneus longus. 
For os calcis. 
For fifth metatarsal. 
Fig. 178.-The left cuboid. A. Antero-internal view. B. Postero-external view. 
behind the fourth and fifth metatarsal bones. It is of a pyramidal shape, its 
base being directed inward, its apex outward. It may be distinguished from 
the other tarsal bones by the existence of a deep groove on its under surface, 
for the tendon of the Peroneus longus muscle. It presents for examination six 
surfaces: three articular and three non-articular. 
Non-articular Surfaces.-The non-articular surfaces are the superior, inferior, and 
external. The superior or dorsal surface, directed upward and outward, is rough, 
for the attachment of numerous ligaments. The inferior or plantar surface presents 
in front a deep groove, the peroneal groove (sulcus m. peroncei longi), which 
runs obliquely from without, forward and inward; it lodges the tendon of the 
Peroneus longus, and is bounded behind by a prominent ridge, to which is 
attached the long calcaneo-cuboid ligament. The ridge terminates externally 
in an eminence, the tuberosity of the cuboid (tuberositas ossis cuboidei), the sur- 
face of which presents a convex facet, for articulation with the sesamoid bone THE SKELETON 
246 
of the tendon contained in the groove. The surface of bone behind the groove 
is rough, for the attachment of the short plantar ligament, a few fibres of the 
Flexor brevis hallucis, and a fasciculus from the tendon of the Tibialis posticus. 
The external surface, the smallest and narrowest of the three, presents a deep 
notch formed by the commencement of the peroneal groove. 
Articular Surfaces.-The articular surfaces are the posterior, anterior, and 
internal. The posterior surface is smooth, triangular, and concavo-convex, for 
articidation with the anterior surface of the os calcis. The anterior surface, of 
smaller size, but also irregularly triangular, is divided by a vertical ridge into 
two facets; the inner one, quadrilateral in form, articulates with the fourth 
metatarsal bone; the outer one, larger and more triangular, articulates with 
the fifth metatarsal. The internal surface is broad, rough, irregularly quadri- 
lateral, presenting at its middle and upper part a smooth oval facet, for articula- 
tion with the external cuneiform bone; and behind this ('occasionally) a smaller 
facet, for articulation with the navicular; it is rough in the rest of its extent, for 
the attachment of strong interosseous ligaments. 
To ascertain to which foot the bone belongs, hold it so that its under surface, 
marked by the peroneal groove, looks downward, and the large concavo-convex 
articular surface backward toward the holder: the narrow non-articular surface, 
marked by the commencement of the peroneal groove, will point to the side to 
which the bone belongs. 
Articulations.-With four bones: the os calcis, external cuneiform, and the 
fourth and fifth metatarsal bones; occasionally with the scaphoid. 
Attachment of Muscles.-Part of the Flexor brevis hallucis and a slip from 
the tendon of the Tibialis posticus. 
Scaphoid or Navicular Bone (os naviculare pedis) (Fig. 179).-The scaphoid 
is situated at the inner side of the tarsus, between the astragalus behind and 
For mid. cuneiform. 
For int. 
cuneiform. 
For ext. 
'cuneiform. 
B 
A 
For cuboid 
(occasional). 
Fig. 179.-The left scaphoid. A. Antero-external view. B. Postero-internal view. 
For astragalus. 
the three cuneiform bones in front. It may be distinguished by its form, being 
concave behind, convex and subdivided into three facets in front. 
Surfaces.-The anterior surface, of an oblong form, is convex from side to side, 
and subdivided by two ridges into three facets, for articulation with the three 
cuneiform bones. The posterior surface is oval, concave, broader externally 
than internally, and articulates with the rounded head of the astragalus. The 
superior surface is convex from side to side, and rough for the attachment of 
ligaments. The inferior is irregular, and also rough for the attachment of liga- 
ments. The internal surface presents a rounded tubercular eminence, the 
tuberosity (tuberositas ossis navicularis), the lower part of which projects, and 
gives attachment to part of the tendon of the Tibialis posticus. The external 
surface is rough and irregular, for the attachment of ligamentous fibres, and 
occasionally presents a small facet for articulation with the cuboid bone. THE TARSUS 
247 
To ascertain to which foot the bone belongs, hold it with the concave articular 
surface backward, and the convex dorsal surface upward; the external surface- 
i. e., the surface opposite the tubercle-will point to the side to which the bone 
belongs. 
Articulations.-With four bones: astragalus and three cuneiform; occasionally 
also with the cuboid. 
Attachment of Muscles.-Part of the Tibialis posticus. 
Cuneiform or Wedge Bones.-The cuneiform bones have received their 
name from their wedge-like shape {cuneus, a wedge; forma, likeness). They 
form, with the cuboid, the anterior row of the tarsus, being placed between 
the scaphoid behind, the three innermost metatarsal bones in front, and the 
cuboid externally. They are called the first, second, and third, counting from 
the inner to the outer side of the foot, and, from their position, internal, middle, 
and external. 
Internal or First Cuneiform (os cuneiforme primum) (Fig. 180).-The inter- 
nal cuneiform is the largest of the three. It is situated at the inner side of 
the foot, between the scaphoid behind and the base of the first metatarsal in 
front. It may be distinguished from 
the other two by its large size, and 
by its not presenting such a distinct 
wedge-like form. Without the others 
it may be known by the large, kidney- 
shaped anterior articulating surface 
and by the prominence on the in- 
ferior or plantar surface for the at- 
tachment of the Tibialis posticus. It 
presents for examination six surfaces. 
Surfaces.-The internal surface is 
subcutaneous, and forms part of the 
inner border of the foot; it is broad, 
quadrilateral, and presents at its an- 
terior inferior angle a smooth oval facet, into which the tendon of the Tibialis 
anticus is partially inserted; in the rest of its extent it is rough, for the attachment 
of ligaments. The external surface is concave, presenting, along its superior and 
posterior borders, a narrow, reversed, L-shaped surface, for articulation with the 
middle cuneiform behind and second metatarsal bone in front; in the rest of its 
extent it is rough, for the attachment of ligaments and part of the tendon of the 
Peroneus longus. The anterior surface, kidney-shaped, much larger than the poste- 
rior, articulates with the metatarsal bone of the great toe. The posterior surface 
is triangular, concave, and articulates with the innermost and largest of the three 
facets on the anterior surface of the scaphoid. The inferior or plantar surface 
is rough, and presents a prominent tuberosity at its back part for the attachment 
of part of the tendon of the Tibialis posticus. It also gives attachment in front 
to part of the tendon of the Tibialis anticus. The superior surface is the narrow- 
pointed end of the wedge, which is directed upward and outward; it is rough 
for the attachment of ligaments. 
To ascertain to which side the bone belongs, hold it so that its superior narrow 
edge looks upward, and the long, kidney-shaped, articular surface forward; the 
external surface, marked by its vertical and horizontal articular facets, will 
ooint to the side to which it belongs. 
Articulations.-With four bones: scaphoid, middle cuneiform, first and second 
metatarsal bones. 
Attachment of Muscles.-To three: the Tibialis anticus and posticus, and 
Peroneus longus. 
For first 
metatarsal. 
For second 
metatarsal. 
For middle 
cuneiform. 
A 
B 
For tendon of Tibialis ant. 
Fig. 180.-The left internal cuneiform. A. Antero- 
internal view. B. Postero-external view. 
For navicular. 248 
THE SKELETON 
Middle or Second Cuneiform (os Cuneiforms secundum) (Fig. 181).-The 
middle cuneiform, the smallest of the three, is of very regular wedge-like form, 
the broad extremity being placed upward, the narrow end downward. It is 
situated between the other two bones of the same name, and articulates with the 
scaphoid behind and the second metatarsal in front. It is smaller than the external 
cuneiform bone, from which it may be further distinguished by the L-shaped 
articular facet, which runs round the upper and back part of its inner surface. 
Surfaces.-The anterior surface, triangular in form and narrower than the poste- 
rior, articulates with the base of the second metatarsal bone. The posterior sur- 
face, also triangular, articulates with the scaphoid. The internal surface presents 
a reversed L-shaped articular facet, running along the superior and posterior 
borders, for articulation with the internal cuneiform, and is rough in the rest 
of its extent, for the attachment of ligaments. The external surface presents 
posteriorly a smooth facet for articulation with the external cuneiform bone. 
The superior surface forms the base of the wedge; it is quadrilateral, broader 
behind than in front, and rough for the attachment of ligaments. The inferior 
surface, pointed and tubercular, is also rough for ligamentous attachment and 
for the insertion of a slip from the tendon of the Tibialis posticus. 
For int. cuneiform 
For navicular. 
For navicular. 
For fourth 
metatarsal. 
For cuboid. 
For mid. ctmeiform. 
A 
B 
A 
B 
For 
second metatarsal. 
For third 
. metatarsal. 
For second 
metatarsal. 
For ext. cuneiform. 
Fig. 181.-The left middle cuneiform. A. Antero- 
internal view. B. Postero-external view. 
Fig. 182.-The left external cuneiform. A. Postero-internal 
view. B. Antero-external view. 
To ascertain to which foot the bone belongs, hold its superior or dorsal surface 
upward, the broadest edge being toward the holder: the smooth facet (limited 
to the posterior border) will then point to the side to which it belongs. 
Articulations.-With four bones: scaphoid, internal and external cuneiform, 
and second matatarsal bone. 
Attachment of Muscles.-A slip from the tendon of the Tibialis posticus is 
attached to this bone. 
External or Third Cuneiform (os cuneiforme tertium) (Fig. 182).-The exter- 
nal cuneiform, intermediate in size between the two preceding, is of a very 
regular wedge-like form, the broad extremity being placed upward, the narrow 
end downward. It occupies the centre of the front row of the tarsus, between 
the middle cuneiform internally, the cuboid externally, the scaphoid behind, and 
the third metatarsal in front. It is distinguished from the internal cuneiform 
bone by its more regular wedge-like shape and by the absence of the kidney- 
shaped articular surface: from the middle cuneiform, by the absence of the 
reversed L-shaped facet, and by the two articular facets which are present on 
both its inner and outer surfaces. It has six surfaces for examination. 
Surfaces.-The anterior surface, triangular in form, articulates with the third 
metatarsal bone. The posterior surface articulates with the most external facet 
of the scaphoid, and is rough below for the attachment of ligamentous fibres. 
The internal surface presents two articular facets, separated by a rough depres- 
sion; the anterior one, sometimes divided into two, articulates with the outer side 
of the base of the second metatarsal bone; the posterior one skirts the posterior 
border and articulates with the middle cuneiform; the rough depression between THE METATARSAL BONES 
249 
the two gives attachment to an interosseous ligament. The external surface also 
presents two articular facets, separated by a rough non-articular surface; the 
anterior facet, situated at the superipr angle of the bone, is small, and articulates 
with the inner side of the base of the fourth metatarsal; the posterior and larger 
one articulates with the cuboid; the rough, non-articular surface serves for the 
attachment of an interosseous ligament. The three facets for articulation with 
the three metatarsal bones are continuous with one another, and covered by a 
prolongation of the same cartilage; the facets for articulation with the middle 
cuneiform and scaphoid are also continuous, but that for articulation with he 
cuboid is usually separate. The superior or dorsal surface is of an oblong square 
form, its posterior external angle being prolonged backward. The inferior or 
plantar surface is an obtuse rounded margin, and serves for the attachment of 
part of the tendon of the Tibialis posticus, part of the Flexor brevis hallucis, 
and ligaments. 
To ascertain to which side the bone belongs, hold it with the broad dorsal 
surface upward, the prolonged edge backward; the separate articular facet for 
the cuboid will point to the proper side. 
Articulations.-With six bones: the scaphoid, middle cuneiform, cuboid, and 
second, third, and fourth metatarsal bones. 
Attachment of Muscles.-To two: part of the Tibialis posticus, and Flexor 
brevis hallucis. 
The number of tarsal bones may be reduced owing to congenital ankylosis 
which may occur between the os calcis and cuboid, the os calcis and scaphoid, 
the os calcis and astragalus, or the astragalus and scaphoid. 
The Metatarsal Bones (Ossa Metatarsalia). 
The metatarsal bones are five in number, and are numbered one to five, in 
accordance with their position from within outward; they are long bones, and 
present for examination a shaft and two extremities. 
Common Characters.-The shaft (corpus) is prismoid in form, tapers gradually 
from the tarsal to the phalangeal extremity, and is slightly curved longitudinally, 
so as to be concave below, slightly convex above. On the plantar surface of the 
shaft of each bone is a nutrient foramen corresponding to the nutrient foramen 
in each metacarpal bone. The posterior or proximal extremity, or base (basis), 
is wedge-shaped, articulating by its terminal surface with the tarsal bones, and 
by its lateral surfaces with the contiguous metatarsal bones, its dorsal and plantar 
surfaces being rough for the attachment of ligaments. The anterior or distal 
extremity, or head (capitulum), presents a terminal rounded articular surface, 
oblong from above downward, and extending farther backward below than 
above. Its sides are flattened and present a depression, surmounted by a 
tubercle, for ligamentous attachment. Its under surface is grooved in the 
middle line for the passage of the Flexor tendon, and marked on each side by 
an articular eminence continuous with the terminal articular surface. 
Peculiar Characters. First Metatarsal Bone or the Metatarsal Bone of the Great 
Toe (os metatarsale I).-The first (Fig. 183) is remarkable for its great thickness, 
but is the shortest of all the metatarsal bones. The shaft is strong and of well- 
marked prismoid form. The posterior extremity presents, as a rule, no lateral 
articular facet, but occasionally on the outer side there is an oval facet by which 
it articulates with the second metatarsal bones. Its terminal articular surface is of 
large size and kidney-shaped; its circumference is grooved, for the tarso-metatarsal 
ligaments, and internally gives attachment to part of the tendon of the 'Tibialis 
anticus muscle; its inferior angle presents a rough oval prominence, the tuberosity 
(tuberositas ossis metatarsalis I), for the insertion of the tendon of the Peroneus 250 
THE SKELETON 
longus. The head is of large size; on its plantar surface are two grooved facets, 
over which glide sesamoid bones; the facets are separated by a smooth elevated 
ridge. 
This bone is known by the single kidney-shaped articular surface on its base, 
the deeply grooved appearance of the plantar surface of its head, and its great 
thickness relatively to its length. 
When it is placed in its natural 
position, the concave border of 
the kidney-shaped articular sur- 
face on its base points to the 
side to which the bone belongs. 
Attachment of Muscles.-To 
three-, part of the Tibialis anti- 
cus, the Peroneus longus, and 
the First dorsal interosseous. 
Second Metatarsal (os metatar- 
sale II).-The second (Fig. 184) 
is the longest and largest of the 
remaining metatarsal bones, be- 
ing prolonged backward into the 
recess formed between the three 
cuneiform bones. Its tarsal ex- 
tremity is broad above, narrow 
and rough below. It presents 
four articular surfaces: one be- 
hind, of a triangular form, for articulation with the middle cuneiform; one at the 
upper part of its internal lateral surface, for articulation with the internal cunei- 
For 
peroneus 
longus. 
For internal cuneiform. 
Occasional facet Jot- 
second metatarsal. 
Fig. 183.-The first metatarsal. (Left.) 
For third 
metatarsal. 
For internal 
cuneiform. 
Occasional 
facet for first 
metatarsal. 
For middle cuneiform. 
For external 
cuneiform. 
For second metatarsal. 
For middle cuneiform. 
For fourth 
metatarsal. 
Fig. 184.-The second metatarsal. (Left.) 
Fig. 185.-The third metatarsal. (Left.) 
form; and two on its external lateral surface-an upper and a lower, separated by 
a rough non-articular interval. Each of these articular surfaces is divided by a 
vertical ridge into two facets, thus making four facets; the two anterior of these THE METATARSAL BONES 
251 
articulate with the third metatarsal; the two posterior (sometimes continuous) with 
the external cuneiform. In addition to these articular surfaces there is occasion- 
ally a fifth when this bone articulates with the first metatarsal bone. It is oval in 
shape, and is situated on the inner side of the shaft near the base. 
The facets on the tarsal extremity of the second metatarsal bone serve at once 
to distinguish it from the rest, and to indicate the foot to which it belongs; there 
being one facet at the upper angle of the internal surface, and two facets, each 
subdivided into two parts, on the external surface, pointing to the side to which 
the bone belongs. The fact that the two posterior subdivisions of these external 
facets sometimes run into one should not be forgotten. 
Attachment of Muscles.-To four: the Adductor obliquus hallucis, First and 
■Second dorsal interosseous, and a slip from the tendon of the Tibialis posticus; 
occasionally also a slip from the Peroneus longus. 
Third Metatarsal (os metatarsale III).-The third metatarsal (Fig. 185) articu- 
lates behind, by means of a triangular smooth surface, with the external cunei- 
form; on its inner side, by two facets, with the second metatarsal; and on its 
outer side, by a single facet, with the fourth metatarsal. The latter facet is of 
circular form and situated at the upper angle of the base. 
The third metatarsal is known by its having at its tarsal end two undivided 
facets on the inner side, and a single facet on the outer. This distinguishes it 
from the second metatarsal, in which the two facets, found on one side of its 
tarsal end, are each subdivided into two. The single facet (when the bone is put 
in its natural position) is on the side to which the bone belongs. 
Attachment of Muscles.-To five: Adductor obliquus hallucis, Second and 
Third dorsal, and First plantar interosseous, and a slip from the tendon of the 
Tibialis posticus. 
Fourth Metatarsal (os metatarsale IV).-The fourth metatarsal (Fig. 186) is 
smaller in size than the preceding; its tarsal extremity presents a terminal quad- 
For third 
metatarsal. 
For ext. cuneiform. 
For cuboid. 
For fifth 
metatarsal. 
For fourth 
metatarsal. 
Tuberosity. 
Fig. 186.-The fourth metatarsal. (Left.) 
Fig. 187.-The fifth metatarsal. (Left.) 
For cuboid. 
rilateral surface, for articulation with the cuboid; a smooth facet on the inner 
side, divided by a ridge into an anterior portion for articulation with the third THE SKELETON 
252 
metatarsal, and a posterior portion for articulation with the external cuneiform; 
on the outer side a single facet, for articulation with the fifth metatarsal. 
The fourth metatarsal is known by its having a single facet on either side of 
the tarsal extremity, that on the inner side being divided into two parts. If this 
subdivision be not recognizable, the fact that its tarsal end is bent somewhat 
outward will indicate the side to which it belongs. 
Attachment of Muscles.-To five: Adductor obliquus hallucis, Third and 
Fourth dorsal, and Second plantar interosseous, and a slip from the tendon of the 
Tibialis posticus. 
Fifth Metatarsal Bone, or the Metatarsal Bone of the Little Toe (os metatarsale V). 
-The fifth metatarsal (Fig. 187) is recognized by the tubercle (tuberositas ossis 
metatarsalis F) on the outer side of its base. It articulates behind, by a tri- 
angular surface cut obliquely from without inward, with the cuboid, and inter- 
nally with the fourth metatarsal. 
The projection on the outer side of this bone at its tarsal end at once distin- 
guishes it from the others, and points to the side to which it belongs. 
Attachment of Muscles.-To six: the Peroneus brevis, Peroneus tertius, 
Flexor brevis minimi digiti, Adductor transversus hallucis, Fourth dorsal, and 
Third plantar interossei. 
Articulations.-Each bone articulates with the tarsal bones by one extremity, 
and by the other with the first row of phalanges. The number of tarsal bones 
with which each metatarsal articulates is one for the first, three for the second, 
one for the third, two for the fourth, and one for the fifth. 
The Phalanges of the Foot (Phalanges Digitorum Pedis). 
The phalanges of the foot, both in number and general arrangement, resemble 
those in the hand; there being two in the great toe and three in each of the 
other toes. The nutritive foramina correspond to those in the phalanges of the 
hand. 
The first or proximal phalanx (phalanx prima) resembles closely the correspond- 
ing bone of the hand. The shaft also is compressed from side to side, convex 
above, concave below. The posterior extremity is concave; and the anterior 
extremity presents a trochlear surface, for articulation with the second phalanx. 
The second phalanx (phalanx secunda) is remarkably small and short, but 
rather broader than the first phalanx. 
The ungual or distal phalanx (phalanx tertia) in form resembles the bone of the 
corresponding finger, but is smaller, flattened from above downward, presenting a 
broad base for articulation with the second phalanx, and an expanded extremity 
for the support of the nail and end of the toe. 
Articulation.-The first row, with the metatarsal bones behind and second 
phalanges in front; the second row of the four outer toes, with the first and third 
phalanges; of the great toe, with the first phalanx; the third row of the four outer 
toes, with the second phalanges. 
Attachment of Muscles.-To the first phalanges. Great toe, five muscles: 
innermost tendon of Extensor brevis digitorum, Abductor hallucis, Adductor 
obliquus hallucis, Flexor brevis hallucis, Adductor transversus hallucis. Second 
toe, three muscles: First and Second dorsal interosseous and First lumbrical. 
Third toe, three muscles: Third dorsal and First plantar interosseous and Second 
lumbrical. Fourth toe, three muscles: Fourth dorsal and Second plantar inter- 
osseous and Third lumbrical. Fifth toe, four muscles: Flexor brevis minimi 
digiti, Abductor minimi digiti, and Third plantar interosseous, and Fourth 
lumbrical.-Second phalanges. Great toe; Extensor longus hallucis, Flexor 
longus hallucis. Other toes; Flexor brevis digitorum, one slip of the common DEVELOPMENT OF THE FOOT 
253 
tendon of the Extensor longus and brevis digitorum.1-Third phalanges: two slips 
from the common tendon of the Extensor longus and Extensor brevis digitorum, 
and the Flexor longus digitorum. 
Development of the Foot (Fig. 188). 
The Tarsal Bones are each developed by a single centre, excepting the os calcis 
which has an epiphysis for its posterior extremity. The centres make their appear- 
ance in the following order: os calcis, at the sixth month of foetal life; astragalus, 
Appears 10th year; 
unites after puberty. 
Tarsus. 
One centre for each bone, 
except os calcis. 
Metatarsus. 
Two centres for each bone: 
One for shaft, 
One for digital extremity 
except 1st. 
Appears 5th year. 
Unite 18th-20 year. 
Appears 7th week. 
Appears 7 th week.' 
Unite 18th-20th year. 
Appears 3rd year. 
Appears 4th year.. 
Phalanges. 
Two centres for each bone: 
One for shaft, 
One for metatarsal 
extremity. 
Unite 17-18th year. 
Appears 2nd-4th month.- 
' g 
Appears 6th-7th year.^ 
Unite 17th-18th year. 
,5 
I * 
Appears 2nd~4th month. 
Appears 6th year. 
I 
SO 
Unite 17th-18th year. 
Appears 7th week. 
Fig. 188.-Plan of the development of the foot. 
about the seventh month; cuboid, at the ninth month; external cuneiform, dur- 
ing the first year; internal cuneiform in the third year; middle cuneiform and 
scaphoid in the fourth year. The epiphysis for the posterior tuberosity of the 
os calcis appears at the tenth year, and unites with the rest of the bone soon 
after puberty. 
The Metatarsal Bones are each developed by two centres: one for the shaft 
and one for the digital extremity in the four outer metatarsal; one for the shaft 
and one for the base in the metatarsal bone of the great toe.2 Ossification com- 
1 Except the second phalanx of the fifth toe, which receives no slip from the Extensor brevis digitorum. 
2 As was noted in the first metacarpal bone, so in the first metatarsal, there is often to be observed a tendency 
to the formation of a second epiphysis in the distal extremity. 254 
THE SKELETON 
mences in the centre of the shaft about the ninth week, and extends toward 
either extremity. The centre in the proximal end of the first metatarsal bone 
appears about the third year, the centre in the distal end of the other bones 
between the fifth and eighth years; they become joined between the eighteenth 
and twentieth years. 
The Phalanges are developed by two centres for each bone: one for the shaft 
and one for the metatarsal extremity. The centre for the shaft appears about the 
tenth week, that for the epiphysis between the fourth and tenth years; they join 
the shaft about the eighteenth year. 
Construction of the Foot as a Whole (Figs. 189, 190). 
The foot is constructed on the same principles as the hand, but modified to form 
a firm basis of support for the rest of the body when in the erect position. It 
is more solidly constructed, and its component parts are less movable on each 
other than in the hand. This is especially the case with the great toe, which has 
Fig. 189.-Skeleton of the foot, internal border. (Poirier and Charpy.) 
to assist in supporting the body, and is therefore constructed with greater solidity; 
it lies parallel with the other toes, and has a very limited degree of mobility, 
whereas the thumb, which is occupied in numerous and varied movements, is 
constructed in such a manner as to permit of great mobility. Its metacarpal bone 
SECOND CUNEIFORM 
SECOND METATARSAL 
Fig. 190.-Skeleton of the foot, external border. (Poirier and Charpy.) 
is directed away from the others, so as to form an acute angle with the second, 
and it enjoys a considerable range of motion at its articulation with the carpus. 
The foot is placed at right angles to the leg-a position which is almost peculiar 
to man, and has relation to the erect position which he maintains. In order to 
allow of its supporting the weight of the whole body in this position with the 
least expenditure of material, it is constructed in the form of an arch. This 
antero-posterior or longitudinal arch is made up of two unequal limbs. The CONSTRUCTION OF THE FOOT AS A WHOLE 
255 
hinder one, which is made up of the os calcis and the posterior part of the 
astragalus, is about half the length of the anterior limb, and measures about 
three inches. The anterior limb consists of the rest of the tarsal and the meta- 
tarsal bones, and measures about seven inches. It may be said to consist of two 
parts, an inner segment made up of the head of the astragalus, the scaphoid, 
the three cuneiform, and the three inner metatarsal bones; and an outer segment 
composed of the os calcis, the cuboid, and the two outer metatarsal bones. The 
summit of the arch is at the superior articular surface of the astragalus; and its 
two extremities-that is to say, the two piers on which the arch rests in standing 
-are the tubercles on the under surface of the os calcis posteriorly, and the heads 
of the metatarsal bones anteriorly. The weakest part of the arch is the joint 
between the astragalus and scaphoid, and here it is more liable to yield in those 
who are overweighted, and in those in whom the ligaments which complete and 
preserve the arch are relaxed. This weak point in the arch is braced on its con- 
cave surface by the inferior calcaneo-scaphoid ligament, which is more elastic 
than most other ligaments, and thus allows the arch to yield from jars or shocks 
applied to the anterior portion of the foot and quickly restores it to its pristine 
condition. This ligament is supported internally by blending with the Deltoid 
ligament, and inferiorly by the tendon of the Tibialis posticus muscle, which is 
spread out into a fan-shaped insertion, and prevents undue tension of the ligament 
or such an amount of stretching as would permanently elongate it. 
In addition to this longitudinal arch the foot presents a transverse arch, at the 
anterior part of the tarsus and hinder part of the metatarsus. This, however, can 
scarcely be described as a true arch, but presents more the character of a half- 
dome. The inner border of the central portion of the longitudinal arch is elevated 
from the ground, and from this point the bones arch over to the outer border, 
which is in contact with the ground, and, assisted by the longitudinal arch, pro- 
duce a sort of rounded niche on the inner side of the foot, which gives the appear- 
ance of a transverse as well as a longitudinal arch. 
The line of the foot, from the point of the heel to the toes, is not quite straight, 
but is directed a little outward, so that the inner border is a little convex and the 
outer border concave. This disposition of the bones becomes more marked when 
the longitudinal arch of the foot is lost, as in the disease known under the name 
of "flat-foot." 
Surface Form.- On the dorsum of the foot the individual bones are not to be distinguished 
with the exception of the head of the astragalus, which forms a rounded projection in front of 
the ankle-joint when the foot is forcibly extended. The whole surface forms a smooth convex 
outline, the summit of which is the ridge formed by the head of the astragalus, the scaphoid, 
the middle cuneiform, and the second metatarsal bones; from this it gradually inclines outward 
and more rapidly inward. On the inner side of the foot, the internal tuberosity of the os calcis 
and the ridge separating the inner from the posterior surface of the bone may be felt most poste- 
riorly. In front of this, and below the internal malleolus, may be felt the projection of the 
sustentaculum tali. Passing forward is the well-marked tuberosity of the scaphoid bone, situ- 
ated about an inch or an inch and a quarter in front of the internal malleolus. Further toward 
the front, the ridge formed by the base of the first metatarsal bone can be obscurely felt, and 
from this the shaft of the bone can be traced to the expanded head articulating with the base 
of the first phalanx of the great toe. Immediately beneath the base of this phalanx, the internal 
sesamoid bone is to be felt. Lastly, the expanded ends of the bones forming the last joint of 
the great toe are to be felt. On the outer side of the foot the most posterior bony point is the 
outer tuberosity of the os calcis, with the ridge separating the posterior from the outer surface 
of the bone. In front of this the greater part of the external surface of the os calcis is subcu- 
taneous; on it, below and in front of the external malleolus, may be felt the peroneal ridge, when 
this process is present. Farther forward, the base of the fifth metatarsal bone forms a prom- 
inent and well-defined landmark, and in front of this the shaft of the bone, with its expanded 
head, and the base of the first phalanx may be defined. The sole of the foot is almost entirely 
covered by soft parts, so that but few bony parts are to be made out, and these somewhat 
obscurely. The hinder part of the under surface of the os calcis and the heads of the metatarsal 256 
THE SKELETON 
bones, with the exception of the first, which is concealed by the sesamoid bones, may be recog- 
nized. 
Surgical Anatomy.-Considering the injuries to which the foot is subjected, it is surpris- 
ing how seldom the tarsal bones are fractured. This is no doubt due to the fact that the tarsus 
is composed of a number of bones, articulated by a considerable extent of surface and joined 
together by very strong ligaments, which serve to mitigate the intensity of violence applied to this 
part of the body. When fracture does occur, these bones, being composed for the most part 
of a soft cancellous structure, covered only by a thin shell of compact tissue, are often extensively 
comminuted, especially as most of the fractures are produced by direct violence. As the bones 
have only a very scanty amount of soft parts over them, fractures are very often compound, and 
amputation is frequently necessary. 
When fracture occurs in the anterior group of tarsal bones, it is almost invariably the result 
of direct violence; but fractures of the posterior group, that is, of the calcaneum and astrag- 
alus, are most frequently produced by falls from a height on to the feet; though fracture of the 
os calcis may Be caused by direct violence or by muscular action. The posterior part of the 
bone, that is, the part behind the articular surfaces, is almost always the seat of the fracture, 
though some few cases of fracture of the sustentaculum tali and of vertical fracture between 
the two articulating facets have been recorded. The neck of the astragalus, being the weakest 
part of the bone, is most frequently fractured, though fractures may occur in any part and 
almost in any direction, either associated or not with fracture of other bones. 
In cases of club-foot, especially in congenital cases, the bones of the tarsus become altered 
in shape and size, and displaced from their proper positions. This is especially the case in con- 
genital equino-varus, in which the astragalus, particularly about the head, becomes twisted and 
atrophied, and a similar condition may be present in the other bones, more especially the sca- 
phoid. The tarsal bones are peculiarly liable to become the seat of tuberculous caries, and this 
condition may arise after comparatively trivial injuries. There are several reasons to account 
for this. They are composed of a delicate cancellated structure, surrounded by intricate synovial 
membranes. They are situated at the farthest point from the central organ of the circulation 
and exposed to vicissitudes of temperature; and, moreover, on their dorsal surface are thinly 
clad with soft parts which have but a scanty blood-supply. And finally, after slight injuries, 
they are not maintained in a condition of rest to the same extent as structures suffering from 
similar injuries in some other parts of the body. Caries of the calcaneus or astragalus 
may remain limited to the one bone for a long period, but when one of the other bones is 
affected, the remainder frequently become involved, in consequence of the disease spreading 
through the large and complicated synovial membrane which is more or less common to these 
bones. 
Amputation of the whole or a part of the foot is frequently required either for injury or 
disease. The principal amputations are as follows: (1) Syme's : amputation at the ankle-joint 
by a heel-flap, with removal of the malleoli and a thin slice from the lower end of the tibia. 
(2) Roux's: amputation at the ankle-joint by a large internal flap. (3) Pirogoff's amputa- 
tion : removal of the whole of the tarsal bones, except the posterior part of the os calcis.. A thin 
slice is sawn from the tibia and fibula, including the two malleoli. The sawn surface of the os 
calcis is then turned up and united to the similar surface of the tibia. (4) Subastragaloid 
amputation : removal of the foot below the astragalus through the joint between it and the os 
calcis. This operation has been modified by Hancock, who leaves the posterior third of the os 
calcis and turns it up against the denuded surface of the astragalus. This latter operation is of 
doubtful utility and is rarely performed. (5) Chopart's or medio-tarsal: removal of the ante- 
rior part of the foot with all the tarsal bones except the os calcis and astragalus; disarticula- 
tion being effected through the astragalo-scaphoid and calcaneo-cuboid joints. (6) Lisfranc's : 
amputation of the anterior part of the foot through the tarso-metatarsal joints. This was 
modified by Hey, who disarticulated through the joints of the four outer metatarsal bones with 
the tarsus, and sawed off the projecting internal cuneiform; and by Skey, who sawed off the base 
of the second metatarsal bone and disarticulated the others. 
The bones of the tarsus occasionally require removal individually. This is especially the 
case with the astragalus and os calcis for disease limited to the one bone, or again the astragalus 
may require excision in cases of subastragaloid dislocation, or, as recommended by M.r Lund, 
in cases of inveterate talipes. The cuboid has been removed for the same reason by Mr. Solly. 
But the latter two operations have fallen into disuse, and have been superseded by resection 
of a wedge-shaped piece of bone from the outer side of the tarsus. Finally, Mickulicz and 
Watson have devised operations for the removal of more extensive portions of the tarsus. 
Mickulicz's operation consists in the removal of the os calcis and astragalus, along with the 
articular surfaces of the tibia and fibula, and also of the scaphoid and cuboid. The remain- 
ing portion of the tarsus is then brought into contact with the sawn surfaces of the tibia and 
fibula, and fixed there. The result is a position of the shortened foot resembling talipes 
equinus. IFa^on's operation is adapted to those cases where the disease is confined to the 
anterior tarsal bones. By two lateral incisions he saws through the bases of the metatarsal SESAMOID BONES 
257 
bones in front and opens up the joints between the scaphoid and astragalus, and the cuboid and 
os calcis, and removes the intervening bones. 
Fractures of the metatarsal bones and phalanges are nearly always due to direct violence, and 
in many cases the injury is the result of severe crushing accidents, necessitating amputation. 
The metatarsal bones, and especially the metatarsal bone of the great toe, are frequently dis- 
eased, either in tuberculous subjects or in perforating ulcer of the foot. 
Sesamoid Bones (Ossa Sesamoidea) (Figs. 191, 192). 
These are small rounded masses, cartilaginous in early life, osseous in the adult, 
which are developed in those tendons which exert a great amount of pressure upon 
the parts over which they glide. It is said that they are more commonly found in 
the male than in the female, and in persons of an active muscular habit than in 
those who are weak and debilitated. They are invested throughout their whole 
surface by the fibrous tissue of the tendon in which they are found, excepting upon 
that side which lies in contact with the part over which they play, where they 
present a free articular facet. They may be divided into two kinds: those which 
glide over the articular surfaces of the joints, and those which play over the cartilag- 
inous facets found on the surfaces of certain bones. 
Fig. 191.-Sesamoid bones of the hand. (Poirier 
and Charpy.) 
Fig. 192.-Sesamoid bones of the 
foot. (Poirier and Charpy.) 
The sesamoid bones of the joints in the upper extremity are two on the palmar 
surface of the metacarpo-phalangeal joint in the thumb, developed in the tendons 
of the Flexor brevis pollicis; one on the palmar surface of the interphalangeal 
joint of the thumb; occasionally one or two opposite the metacarpo-phalangeal 
articulations of the fore and little fingers; and, still more rarely, one opposite 
the same joints of the third and fourth fingers. In the lower extremity, the 
patella, which is developed in the tendon of the Quadriceps extensor; two 
small sesamoid bones, found in the tendons of the flexor brevis hallucis, opposite 
the metatarso-phalangeal joint of the great toe; one sometimes over the inter- 
phalangeal joint of the great toe; and occasionally one in the metatarso-phalan- 
geal joint of the second toe, the little toe, and, still more rarely, the third and 
fourth toes. 258 
THE SKELETON 
Those found in the tendons which glide over certain bones occupy the following 
situations: one sometimes found in the tendon of the Biceps cubiti, opposite the 
tuberosity of the radius: one in the tendon of the Peroneus longus, where it glides 
through the groove in the cuboid bone; one appears late in life in the tendon of the 
Tibialis anticus, opposite the smooth facet of the internal cuneiform bone; one is 
found in the tendon of the Tibialis posticus, opposite the inner side of the head 
of the astragalus; one in the outer head of the Gastrocnemius, behind the outer 
condyle of the femur; and one in the conjoined tendon of the Psoas and Iliacus, 
where it glides over the os pubis. Sesamoid bones are found occasionally in the 
tendon of the Gluteus maximus, as it passes over the great trochanter, and in 
the tendons which wind round the inner and outer malleoli. THE ARTICULATIONS OR JOINTS. 
THE various bones of which the Skeleton consists are connected together at 
different parts of their surfaces, and such a connection is designated by the 
name of joint or articulation. Arthrology is the branch of anatomy which treats of 
the joints. If the joint is immovable, as between the cranial and most of the 
facial bones, the adjacent margins of the bones are applied in almost close con- 
tact, a thin layer of fibrous membrane, the sutural ligament, and, at the base of 
the skull, in certain situations, a thin layer of cartilage, being interposed. Where 
slight movement is required, combined with great strength, the osseous surfaces 
are united by tough and elastic fibro-cartilages, as in the joints between the 
vertebral bodies and interpubic articulations; but in the movable joints the bones 
forming the articulation are generally expanded for greater convenience of mutual 
connection, covered by cartilage, held together by strong bands or capsules of 
fibrous tissue called ligaments, and partially lined by a membrane, the synovial 
membrane, which secretes a fluid to lubricate the various parts of which the joint 
is formed; so that the structures which enter into the formation of a joint are 
bone, cartilage, fibro-cartilage, ligament, and synovial membrane. 
Bone.-Bone constitutes the fundamental element of all the joints. In the 
long bones the extremities are the parts which form the articulations; they are 
generally somewhat enlarged, consisting of spongy cancellous tissue, with a thin 
coating of compact substance. In the flat bones the articulations usually take 
place at the edges, and, in the short bones, at various parts of their surface. The 
layer of compact bone which forms the articular surface, and to which the car- 
tilage is attached, is called the articular lamella. It is of a white color, extremely 
dense, and varies in thickness. Its structure differs from ordinary bone-tissue 
in this respect, that it contains no Haversian canals, and its lacunae are much 
larger than in ordinary bone and have no canaliculi. The vessels of the can- 
cellous tissue, as they approach the articular lamella, turn back in loops, and 
do not perforate it; this layer is consequently more dense and firmer than ordinary 
bone, and is evidently designed to form a firm and unyielding support for the 
articular cartilage. 
Cartilage.-Cartilage is material which is a transition stage of connective tissue 
into bone. When boiled it yields chondrin. Cartilage is not vascular and is found 
in various parts of the body; in adult life chiefly in the joints, in the parietes of 
the thorax, and in various tubes, which are to be kept permanently open, such as 
the air passages, nostrils, and ears. In the foetus in an early period the greater part 
of the skeleton is cartilaginous. As this cartilage is replaced by bone, it is called 
temporary in contradistinction to that which remains unossified during life, and 
which is called permanent. Cartilage is divided into: 
1. Hyaline cartilage. 
2. Elastic cartilage. 
3. Fibro-cartilage. 
Hyaline Cartilage.-This structure is found in the nose, larynx, trachea, bronchi, 
and in symphyses and synchondroses; costal cartilage and epiphyseal cartilage 
are composed of it, and as articular cartilage (cartilago articularis) it covers joint 
259 THE ARTICULATIONS OR JOINTS 
260 
surfaces. It is a bluish or pearly hued substance, in reality a modified connective 
tissue, but much harder than most connective tissues. The investing membrane, 
the perichondrium, is composed of two layers: an outer fibrous layer which carries 
blood-vessels and an inner or chondrogenetic layer, which contains cartilage- 
forming cells (chondroblasts). 
Cartilage does not contain blood-vessels except in regions of very active growth 
or of ossification. In such regions vessels may be formed. Hyaline cartilage is 
composed of round or oval cells and intercellular substance. Each cell contains 
granular protoplasm and a nucleus, and the nucleus contains one or two nucleoli. 
The cells are placed in the so-called cartilage spaces of the ground substance, and the 
ground substance immediately surrounding a space is called a cartilage capsule. 
The cells are placed in groups and near the surface are arranged in rows, and in 
some regions are flattened by pressure. 'The intercellular or ground substance 
(matrix) is an apparently homogeneous and structureless material between the 
cartilage spaces. By certain methods, however, fibres can be demonstrated in it. 
These fibrils in general are parallel. In some of the lower animals canals have 
been demonstrated. In man it has not been proved that canals exist, and it has 
been suggested that the fibrils act as paths of conduction for nutritive fluid. 
Articular cartilage forms a thin incrustation upon the joint-surfaces of the 
bones, and its elasticity enables it to break the force of any concussion, while its 
smoothness affords ease and freedom of movement. It varies in thickness accord- 
ing to the shape of the articular surface on which it lies; where this is convex the 
cartilage is thickest at the centre, where the greatest pressure is received; and the 
reverse is the case on the concave articular surfaces. Articular cartilage appears 
to derive its nutriment partly from the vessels of the neighboring synovial mem- 
brane, partly from those of the bone upon which it is implanted. Toynbee has 
shown that the minute vessel of the cancellous tissue as they approach the articular 
lamella dilate and form arches, and then return into the substance of the bone. 
The hyaline cartilages, especially in adult and advanced life, are prone to 
calcify-that is to say, to have their matrix permeated by the salts of lime without 
any appearance of true bone. The process of calcification occurs also, and still 
more frequently, according to Rollett, in such cartilages as those of the trachea 
and in the costal cartilages, which are prone afterward to conversion into true 
bone. 
Elastic Cartilage.-In this structure there are elastic fibres in the matrix, which 
fibres at the periphery of the cartilage enter into the perichondrium. Such carti- 
lage is not blue-white in color, but is a very light yellow, and is not to be regarded 
as identical with elastic fibrous tissue. Elastic cartilage is found in the epiglottis 
and the cartilages of the larynx. 
Fibro-cartilage is composed of white fibrous tissue and cartilage in varying pro- 
portions; it is to the first of these two constituents that its flexibility and toughness are 
chiefly owing, and to the latter its elasticity; the cells are fewer in number, but are 
possessed of more definite capsules than are those of hyaline cartilage, and they 
are usually arranged in groups surrounded by small islands of hyaline matrix, 
which may be concentrically striated. The hyaline islands are separated from 
one another by bundles of white fibrous tissue that pursue a markedly wavy 
course. 
Fibro-cartilage is found at the point of insertion of the ligamentum teres into 
the head of the femur, in the intervertebral disks, in the pubic symphysis, and in 
the interarticular cartilages. 
The fibro-cartilages admit of arrangement into four groups: interarticular, con- 
necting, circumferential, and stratiform. 
1. The interarticular fibro-cartilages {menisci) are flattened, fibro-cartilaginous 
plates, of a round, oval, triangular, or sickle-like form, interposed between the LIGAMENTS 
261 
articular cartilages of certain joints. They are free on both surfaces, thinner 
toward their centre than at their circumference, and held in position by the attach- 
ment of their margins and extremities to the surrounding ligaments. The synovial 
membrane of the joint is prolonged over them a short distance from their attached 
margins. They are found in the temporo-mandibular, sterno-clavicular, acromio- 
clavicular, wrist- and knee-joints. These cartilages are usually found in those 
joints which are most exposed to violent concussion and subject to frequent move- 
ment. Their use is to maintain the apposition of the opposed surfaces in their 
various motions; to increase the depth of the articular surfaces and give ease to 
the gliding movement; to moderate the effects of great pressure and deaden the 
intensity of the shocks to which the parts may be subjected. Humphry has pointed 
out that these interarticular fibro-cartilages serve an important purpose in increasing 
the variety of movements in a joint. Thus, in the knee-joint there are two kinds 
of motion-viz., angular movement and rotation-although it is a hinge joint, in 
which, as a rule, only one variety of motion is permitted; the former movement takes 
place between the condyles of the femur and the interarticular cartilage, the latter 
between the cartilage and the head of the tibia. So, also, in the temporo-man- 
dibular joint, the upward and downward movement of opening and shutting the 
mouth takes place between the fibro-cartilage and the jaw-bone, the grinding 
movement between the glenoid cavity and the fibro-cartilage, the latter moving 
with the jaw-bone. 
Interarticular cartilages may divide the joint into two distinct cavities, as in the 
temporo-maxillary articulation. The periphery of an articular cartilage is attached 
particularly to the capsule and may also be attached to the non-articular portion 
of the bone. The semilunar cartilages of the knee resemble tendon more than 
they do cartilage. The fibres are arranged in dense, more or less parallel bundles, 
separated by small, scattered hyaline cells, and the disks are attached to the bone 
by thin layers of hyaline cartilage. 
2. The connecting fibro-cartilages are interposed between the bony surfaces of 
those joints which admit of only slight mobility, as between the bodies of the 
vertebrae and between the pubic bones. They form disks which adhere closely to 
both of the opposed surfaces, and are composed of concentric rings of fibrous 
tissue, with cartilaginous laminae interposed, the former tissue predominating 
toward the circumference, the latter toward the centre. 
3. The circumferential fibro-cartilages consist of a rim of fibro-cartilage, which 
surrounds the margin of some of the articular cavities, as the cotyloid cavity of 
the hip and the glenoid cavity of the shoulder; they serve to deepen the articular 
surface, and to protect its edges. 
4. The stratiform fibro-cartilages are those which form a thin coating to osseous 
grooves through which the tendons of certain muscles glide. Small masses of 
fibro-cartilages are developed also in the tendons of some muscles, where they 
glide over bones, as in tendons of the Peroneus longus and the Tibialis posticus. 
Ligaments.-Ligaments consist of bands of various forms, serving to connect 
together the articular extremities of bones, and are composed mainly of coarse 
bundles of very dense white fibrous tissue placed parallel with, or closely inter- 
laced with, one another, and presenting a white, shining, silvery aspect. These 
bundles are called fasciculi. They are held together by a cement substance 
containing cells which resemble those of tendon. A ligament is pliant and 
flexible, so as to allow of the most perfect freedom of movement, but it is 
strong, tough, and inextensile, so as not readily to yield under the most 
severely applied force; it is consequently well adapted to serve as the connecting 
medium between the bones. Some ligaments consist entirely of yellow elastic 
tissue (elastic fibrous tissue), the elastic fibres branching considerably, but main- 
taining in general a parallel course. The fibres are in bundles, between which 262 
THE ARTICULATIONS OR JOINTS 
areolar connective tissue lies. The ligamenta subflava, which connect together 
the adjacent arches of the vertebrae in man and the ligamentum nuchae in the 
lower animals are composed of yellow elastic tissue. In these cases it will be 
observed that the elasticity of the ligament is intended to act as a substitute for 
muscular power. 
Synovial Membranes.-These membranes are serous in character. A synovial 
membrane consists of loose connecting tissue (subendothelial tissue), containing fat, 
vessels, and nerves, its inner surface being lined with a single layer of flat endothelial 
cells. The endothelial cells are polyhedral, and each cell possesses a flattened oval 
nucleus. The cells are held together by intercellular cement. It is believed by some 
that little openings occur at intervals in the intercellular cement, but it is held by 
many that the supposed openings are artifacts. Synovial cavities contain a little 
fluid. A non-articular synovial membrane does not actually secrete fluid, but it is 
moistened by lymph which passes through the membrane and into the cavity by 
osmosis. 
Joint cavities and bursa? communicating with joints contain a characteristic 
fluid which is a secretion of the membrane. It is yellowish-white or slightly red- 
dish, somewhat cloudy, viscid like the white of an egg, having a strongly alkaline 
reaction and a slightly saline taste. It consists of fats, salts, albumins, extract- 
ives from lymph, a mucinous body known as synovin,1 and another mucin-like 
body, which is rich in phosphorus (Simon). 'The nature of synovin is uncertain, 
but it is neither a nucleo-albumin nor a mucin (Simon). The second mucin-like 
body is probably a nucleo-albumin (Simon). The quantitative composition of 
synovial fluid varies with motion and rest (Frerichs, Simon). During exercise the 
mucin-like bodies, the albumins, and the extractives increase, and the salts and 
water diminish.2 The synovial membranes found in the body admit of sub- 
division into three kinds-articular, bursal, and vaginal. 
Articular Synovial Membrane.-Articular synovial membrane is found in every 
freely movable joint. It lines the capsule of the joint and is reflected upon the 
non-articular intracapsular portion of the bones which enter into the formation 
of the joint. In the foetus this membrane is said, by Toynbee, to be continued 
over the surface of the cartilages; but in the adult it merely encroaches for a 
short distance upon the margins of the cartilages, to which it is firmly attached; 
it then invests the inner surface of the capsular or other ligaments enclosing the 
joint, and is reflected over the surface of any tendons passing through its cavity, as 
the tendon of the Popliteus in the knee and the tendon of the Biceps in the 
shoulder. Hence the articular synovial membrane may be regarded as a short 
wide tube, attached by its open ends to the margins of the articular cartilages, and 
covering the inner surface of the various ligaments which connect the articular 
surfaces, so that along with the cartilages it completely encloses the joint-cavity. 
In some of the joints the synovial membrane is thrown into folds, which pass 
across the cavity. They are called synovial ligaments, and are especially distinct in 
the knee. In some joints there are flattened folds, subdivided at their margins into 
fringe-like processes (synovial villi), the vessels of which have a convoluted arrange- 
ment. These latter generally project from the synovial membrane near the margin 
of the cartilage and lie flat upon its surface. They consist of connective tissue cov- 
ered with endothelium, and contain fat-cells in variable quantities, and, more rarely, 
isolated cartilage-cells. The larger folds often contain considerable quantities of 
fat. They were described by Clopton Havers as mucilaginous glands, and as the 
source of the synovial secretion. Under certain diseased conditions similar pro- 
cesses are found covering the entire surface of the synovial membrane, forming a 
1 Simon's Physiological Chemistry. 
2 Frerichs' analysis, in Simon's Physiological Chemistry. SYNO VIAL MEMBRANES 
263 
mass of pedunculated fibro-fatty growths which project into the joint. Similar 
structures are also found in some of the bursal and vaginal synovial membranes. 
Bursal Synovial Membrane.-The bursal synovial membranes are sacs inter- 
posed between surfaces which move upon each other, producing friction, as in the 
gliding of a tendon or of the integument over projecting bony surfaces. There are 
two groups of synovial bursae designated according to situation: 1. Those situated 
between the integument and a prominent process of bone. Such a bursa is called 
a subcutaneous synovial bursa {bursa mucosa subcutanea) (Fig. 246). Subcuta- 
neous bursae are found between the integument and the front of the patella, 
over the olecranon, the malleoli, and other prominent parts. 2. Those situated 
between tendons or muscles and the bony or cartilaginous surfaces over which 
the tendons or muscles glide (Figs. 193 and 194). Such a bursa is called a 
SUBTENDINOUS 
BURSA 
Fig. 193.-Scheme of a serous bursa. (Poirier 
and Charpy.) 
Fig. 194.-Scheme of a serous bursa. (Poirier 
and Charpy.) 
subtendinous synovial bursa (bursa mucosa subtendinea). For example, a bursa 
is placed between the Glutei muscles and the surface of the great trochanter. 
Subtendinous bursae are found often about joints and not unusually communicate 
directly with the cavity of the joint by means of an opening in the joint capsule, 
the synovial membrane of the joint being continuous with the synovial mem- 
brane of the bursa. For instance, the bursa between the tendon of the Psoas 
and Iliacus muscles and the capsular ligament of the hip communicates with 
the hip-joint; and the bursa between the under surface of the Subscapularis 
muscle and the neck of the scapula communicates with the shoulder-joint. 
Bursse consist of a thin wall of connective tissue, partially covered by patches 
of cells, and contain a viscid fluid. 
Vaginal Synovial Membrane (Fig. 326).-A vaginal synovial membrane (synovial 
sheath, thecal synovial bursa, vagina mucosa tendinis) serves to facilitate the gliding 
of a tendon in the osseo-fibrous canal through which it passes. The membrane 
is here arranged in the form of a sheath, one layer of which adheres to the wall 
of the canal, and the other is reflected upon the surface of the contained tendon, 
the space between the two free surfaces of the membrane containing synovia. 
These sheaths are chiefly found surrounding the tendons of the Flexor and Ex- 
tensor muscles of the fingers and toes as they pass through the osseo-fibrous 
canals in the hand or foot. A vaginal sheath covers the long head of the biceps 
muscle from its origin to the surgical neck of the humerus (Fig. 222). 
Pads of adipose tissue (synovial fat pads) are found in certain joints between 
the synovial membrane and the surface beneath it. These pads fill up certain 
joint intervals, and by adapting themselves to changes of position maintain the 
form of the joint during movement. 
The articulations are divided into three classes: synarthrosis, or immovable; 
amphiarthrosis, or mixed; and diarthrosis, or movable joints. 264 
THE ARTICULATIONS OR JOINTS 
Synarthrosis (Immovable Articulation). 
Synarthrosis includes all those articulations in which the surfaces of the bones 
are in almost direct contact, being fastened together by an intervening mass of 
connective tissue, and in which there is no joint cavity and no appreciable motion. 
Examples of synarthrosis are the joints between the bones of the cranium and 
of the face, excepting those of the lower jaw. The varieties of synarthrosis are 
four in number: sutura, schindylesis, gomphosis, and synchondrosis. 
Sutura.-Sutura (a seam) is that form of articulation met with only in the 
skull, where the contiguous margins of flat bones are apparently but not really 
in immediate contact, a thin layer of fibrous tissue, sutural membrane, being 
interposed. This membrane is continuous externally with the pericranium and 
internally with the dura mater. In some of the sutures the sutural membrane 
gradually disappears as age advances and the two bones form an osseous fusion. 
Where the articulating surfaces are connected by a series of processes and inden- 
tations interlocked together, it is termed a true suture or sutura vera, of which there 
are three varieties: sutura dentata, serrata, and limbosa. The sutura dentata (dens, 
a tooth) is so called from the tooth-like form of the projecting articular processes, 
as in the suture between the parietal bones. In the sutura serrata (serra, a saw) 
the edges of the two bones forming the articulation are serrated like the teeth 
of a fine saw, as between the two portions of the frontal bone. In the sutura 
limbosa (limbus, a selvage), besides the dentated processes, there is a certain 
degree of bevelling of the articular surfaces, so that the bones overlap one another, 
as in the suture between the parietal and frontal bones. When the articulation 
is formed by roughened surfaces placed in apposition with one another, it is 
termed the false suture (sutura notha), of which there are two kinds: the sutura 
squamosa (squama, a scale), formed by the overlapping of two contiguous bones 
by broad bevelled margins, as in the squamo-parietal (squamous) suture; and 
the sutura harmonia (dpptmla, a joining together), where there is simple apposition 
of two contiguous, rough, bony surfaces, as in the articulation between the two 
superior maxillary bones or of the horizontal plates of the palate bones. 
Schindylesis.-Schindylesis (ayiuda^aiz, a fissure) is that form of articulation 
in which a thin plate of bone is received into a cleft or fissure formed by the sep- 
aration of two laminae in another bone, as in the articulation of the rostrum of the 
sphenoid and perpendicular plate of the ethmoid with the vomer, or in the recep- 
tion of the latter in the fissure between the superior maxillary and palate bones. 
Gomphosis.-Gomphosis (fopnpo^, a nail) is an articulation formed by the 
insertion of a conical process into a socket, as a nail is driven into a board; this 
is not illustrated by any articulation between bones, properly so called, but is 
seen in the articulation of the teeth with the alveoli of the maxillary bones. 
Synchondrosis.-Where the connecting medium is cartilage the joint is termed 
a synchondrosis. This is a temporary form of joint, because the hyaline cartilage 
becomes converted into bone before adult life. Such a joint is found between 
the epiphyses and shafts of long bones. Another example of a synchondrosis is 
the occipito-sphenoid articulation. 
Amphiarthrosis (Mixed Articulation). 
In this form of articulation the contiguous osseous surfaces may be connected 
together by broad flattened disks of fibro-cartilage, of a more or less complex 
structure, which adhere to the end of each bone, as in the articulation between 
the bodies of the vertebra? and the pubic symphyses. This is termed symphysis. 
In a symphysis there is a partial joint cavity which may exhibit an incomplete 
synovial membrane. Each constituent bone is coated with hyaline cartilage and DIARTHROSIS 
265 
the bones are held together by ligaments and intervening fibro-cartilage. The 
bony surfaces of an amphiarthrodial joint may be united by an interosseous liga- 
ment, as in the inferior tibio-fibular articulation. To such an articulation the 
term syndesmosis is applied. A mixed articulation permits limited motion. 
Diarthrosis (Movable Articulation). 
This form of articulation includes the greater number of the joints in the body, 
mobility being their distinguishing character. They are formed by the approxi- 
mation of two contiguous bony surfaces covered with cartilage, connected by 
ligaments and lined by synovial membrane. The varieties of joints in this class 
have been determined by the kind of motion permitted in each. There are two 
varieties in which the movement is uniaxial; that is to say, all movements take 
place Wound one axis. In one form, the ginglymus or hinge-joint, this axis is, 
practically speaking, transverse; in the other, the trochoid or pivot-joint, it is 
longitudinal. There are two varieties where the movement is biaxial or around 
two horizontal axes at right angles to each other or at any intervening axis 
between the two. These are the condyloid-joint and the saddle-joint. There is 
one form of joint where the movement is polyaxial, the enarthrosis or ball-and- 
socket joint. And finally there are the arthrodia or gliding joints. In a diarthrosis 
there is always a joint cavity lined with synovial membrane-the articular sur- 
faces of the bones are covered with hyaline cartilage and the bones are held in 
contact by ligaments. 
Ginglymus or Hinge-joint a hinge)..-In this form of joint the 
articular surfaces are moulded to each other in such a manner as to permit motion 
only in one plane, forward and backward; the extent of motion at the same time 
being considerable. The direction which the distal bone takes in this motion is 
never in the same plane as that of the axis of the proximal bone, and there is 
always a certain amount of alteration from the straight line during flexion. The 
articular surfaces are connected together by strong lateral ligaments, which form 
their chief bond of union. The most perfect forms of ginglymus are the inter- 
phalangeal joints and the joint between the humerus and ulna; the knee and 
ankle are less perfect, as they allow a slight degree of rotation or lateral move- 
ment in certain positions of the limb. 
Trochoid or Pivot-joint or Rotary-joint.-Where the movement is limited to 
rotation, the joint is formed by a pivot-like process turning within a ring, or the 
ring on the pivot, the ring being formed partly of bone, partly of ligament. In 
the superior radio-ulnar articulation the ring is formed partly by the lesser sig- 
moid cavity of the ulna; in the rest of its extent, by the orbicular ligament; here 
the head of the radius rotates within the ring. In the articulation of the odontoid 
process of the axis with the atlas the ring is formed in front by the anterior arch 
of the atlas; behind, by the transverse ligament; here the ring rotates round the 
odontoid process. 
Condyloid or Biaxial Articulation.-In this form of joint an ovoid articular 
head, or condyle, is received into an elliptical cavity in such a manner as to per- 
mit of flexion and extension, adduction and abduction and circumduction, but 
no axial rotation. The articular surfaces are connected together by anterior, 
posterior, and lateral ligaments. An example of this form of joint is found in 
the wrist. 
Articulation by Reciprocal Reception or Saddle-joint.-In this variety the 
articular surfaces are concavo-convex; that is to say, they are inversely convex in 
one direction and concave in the other. The movements are the same as in the 
preceding form; that is to say, there is flexion, extension, adduction, abduction, 
and circumduction, but no axial rotation. The articular surfaces are connected THE ARTICULATIONS OR JOINTS 
266 
by a capsular ligament. The best example of this form of joint is the carpo- 
metacarpal joint of the thumb. 
Enarthrosis, or Ball-and-socket-joint, is that form of joint in which the distal 
bone is capable of motion around an indefinite number of axes which have one 
common centre. It is formed by the reception of a globular head into a deep 
cup-like cavity (hence the name "ball-and-socket"), the parts being kept in 
apposition by a capsular ligament strengthened by accessory ligamentous bands. 
Examples of this form of articulation are found in the hip and shoulder. 
Arthrodia.-Arthrodia is that form of joint which admits of a gliding move- 
ment; it is formed by the approximation of plane surfaces or one slightly concave, 
the other slightly convex, the amount of motion between them being limited by 
the ligaments, or osseous processes, surrounding the articulation; as in the articu- 
lar processes of the vertebrae, the carpal joints, except that of the os magnum 
with the scaphoid and semilunar bones, and the tarsal joints with the exception 
of the joint between the astragalus and the scaphoid. 
Below, in tabular form, are the names, distinctive characters, and examples 
of the different kinds of articulations. 
The Kinds of Movement Admitted in Joints. 
The movements admissible in joints may be divided into four kinds: gliding, 
angular movement, circumduction, and rotation. These movements are often, 
however, more or less combined in the various joints, so as to produce an infinite 
variety, and it is seldom that we find only one kind of motion in any particular joint. 
D entat a, having 
tooth-like processes. 
As in interparietal 
suture. 
Serrata, having ser- 
rated edges like the 
teeth of a saw. 
As in interfrontal 
suture. 
Limb os a, having 
bevelled margins and 
dentated processes. 
As in fronto-parie- 
tal suture. 
S utura ver a 
(true), articulate 
by indented bor- 
ders. 
S utura. Ar- 
ticulation by 
processes and 
indentations 
i nterlocked 
together. 
Synarthrosis, or 
Immovable Joint. 
Surfaces separated 
by fibrous mem- 
brane or by line 
of cartilage, with- 
out any interven- 
ing synovial 
cavity, and im- 
m o v a b 1 y c o n- 
nected with each 
other. 
As in joints of 
cranium and face 
(except lower 
jaw). 
Squamosa, formed 
by thin bevelled mar- 
gins, overlapping each 
other. 
As in squamo-parie- 
tal suture. 
Harmonia, formed by 
the apposition of con- 
tiguous rough surfaces. 
As in intermaxillary 
suture. 
S utura notha 
(false), articulate 
by rough surfaces. 
Schindylesis.-Articulation formed by the reception of a 
thin plate of one bone into a fissure of another. 
As in articulation of rostrum of sphenoid with vomer. 
Gomphosis.-Articulation formed by the insertion of a 
conical process into a socket: the teeth. THE KINDS OF MOVEMENT ADMITTED IN JOINTS 
Symphysis.-Surfaces connected by fibro-cartilage. There 
is a partial joint cavity and may be an incomplete synovial 
membrane. Has limited motion. As in joints between 
bodies of vertebrae. 
Syndesmosis.-Surfaces united by an interosseous liga- 
ment. As in the inferior tibio-fibular articulation. 
267 
A mphiart hr os is, 
Mixed Articula- * 
tion. 
Ginglymus.-Hinge-joint; motion limited to two directions, 
forwaid and backward. Articular surfaces fitted together 
so as to permit of movement in one plane. As in the inter- 
phalangeal joints and the joint between the humerus and the 
ulna. 
Trochoides, or Pivot-joint.-Articulation by a pivot process 
turning within a ring or ring around a pivot. As in superior 
radio-ulnar articulation and atlanto-axial joint. 
Condyloid.-Ovoid head received into elliptical cavity. 
Movements in every direction except axial rotation. As the 
wrist-joint. 
Reciprocal Reception (saddle-joint).-Articular surfaces 
inversely convex in one direction and concave in the other. 
Movement in every direction except axial rotation. As in 
the carpo-metacarpal joint of the thumb. 
Enarthrosis.-Ball-and-socket joint; capable of motion in 
all directions. Articulations by a globular head received 
into a cup-like cavity. As in hip- and shoulder-joints. 
Arthrodia.-Gliding joint; articulations by plane surfaces, 
which glide upon each other. As in carpal and tarsal articu- 
lations. 
Diarthro sis, 
Movable Joint. 
Gliding movement is the most simple kind of motion that can take place in a 
joint, one surface gliding or moving over another without any angular or rotatory 
movement. It is common to all movable joints, but in some, as in the articu- 
lations of the carpus and tarsus, it is the only motion permitted. This movement 
is not confined to plane surfaces, but may exist between any two contiguous 
surfaces, of whatever form, limited by the ligaments which enclose the articu- 
lation. Gliding over a wide range, as is seen in the sliding of the patella over 
the femur, is called coaptation. 
Angular movement occurs only between the long bones, and by it the angle 
between the two bones is increased or diminished. It may take place in four 
directions: forward and backward, constituting flexion or bending and extension 
or straightening, or inward toward and outward from the mesial line of the body, 
constituting adduction and abduction. Abduction of a limb is movement away from 
the mesial line of the body. Adduction of a limb is movement toward the mesial 
line of the body. In the fingers and toes the significance of the terms are different; 
abduction means movement of the fingers away from the middle finger or of the 
toes away from the second toe; adduction means movement of fingers toward 
the middle finger or of the toes toward the second toe. The strictly ginglymoid 
or hinge-joints admit of flexion and extension only. Abduction and adduction, 
combined with flexion and extension, are met with in the more movable joints; 
as in the hip-, shoulder-, and metacarpal-joint of the thumb, and partially in 
the wrist. When two anterior surfaces are brought nearer together, as by 
bending the elbow or wrist, we speak of the movement as ventral, anterior, or 
palmar flexion. If two posterior surfaces are brought nearer together, as by 
bending the knee or wrist, we speak of the movement as posterior or dorsal! 
flexion. 268 
THE ARTICULATIONS OR JOINTS 
At the wrist-joint the bending of the ulnar margin of the hand toward the 
ulnar side of the forearm is ulnar flexion; the bending of the radial margin of 
the hand toward the radial side of the forearm is radial flexion. 
Circumduction is that limited degree of motion which takes place between the 
head of the bone and its articular cavity, whilst the extremity and sides of the limb 
are made to circumscribe a conical space, the base of which corresponds with the 
inferior extremity of the limb, the apex with the articular cavity; this kind of 
motion is best seen in the shoulder- and hip-joints. 
Rotation is the movement of a bone upon an axis, which is the axis of the pivot 
on which the bone turns, as in the articulation between the atlas and axis, when 
the odontoid process serves as a pivot around which the atlas turns; or else is the 
axis of a pivot-like process which turns within a ring, as in the rotation of the 
radius upon the humerus. 
Ligamentous Action of Muscles.-The movements of the different joints of 
a limb are combined by means of the long muscles which pass over more than one 
joint, and which, when relaxed and stretched to their greatest extent, act as 
elastic ligaments in restraining certain movements of one joint, except when 
combined with corresponding movements of the other, these latter movements 
being usually in the opposite direction. Thus the shortness of the hamstring 
muscles prevents complete flexion of the hip, unless the knee-joint is also flexed, 
so as to bring their attachments nearer together. The uses of this arrangement 
are threefold: 1. It co-ordinates the kinds of movement which are the most 
habitual and necessary, and enables them to be performed with the least expendi- 
ture of power. "Thus in the usual gesture of the arms, whether in grasping or 
rejecting, the shoulder and the elbow are flexed simultaneously, and simultane- 
ously extended," in consequence of the passage of the Biceps and Triceps cubiti 
over both joints. 2. It enables the short muscles which pass over only one joint 
to act upon more than one. "Thus, if the Rectus femoris remain tonically of 
such length that, when stretched over the extended hip, it compels extension of 
the knee, then the Gluteus maximus becomes not only an extensor of the hip, but 
an extensor of the knee as well." 3. It provides the joints with ligaments which, 
while they are of very great power in resisting movements to an extent incom- 
patible with the mechanism of the joint, at the same time spontaneously yield 
when necessary. "Taxed beyond its strength, a ligament will be ruptured, 
whereas a contracted muscle is easily relaxed; also, if neighboring joints be 
united by ligaments, the amount of flexion or extension of each must remain in 
constant proportion to that of the other; while, if the union be by muscles, the 
separation of the points of attachment of those muscles may vary considerably 
in different varieties of movement, the muscles adapting themselves tonically 
to the length required." The quotations are from a very interesting paper by 
Dr. Cleland in the Journal of Anatomy and Physiology, No. 1, 1866, p. 85; by 
whom I believe this important fact in the mechanism of joints was first clearly 
pointed out, though it has been independentlv observed afterward by other 
anatomists. Dr. W. W. Keen points out how important it is "that the surgeon 
should remember this ligamentous action of muscles in making passive motion- 
for instance, at the wrist after Colles's fracture. If the fingers be extended, the 
wrist can be flexed to a right angle. If, however, they be first flexed, as in 'mak- 
ing a fist,' flexion at the wrist is quickly limited to from 40 to 50 degrees in 
different persons, and is very painful beyond that point. Hence passive motion 
here should be made with the fingers extended. In the leg, when flexing the hip, 
the knee should be flexed." Dr. Keen further points out that "a beautiful illus- 
tration of this is seen in the perching of birds, whose toes are forced to clasp the 
perch by just such a passive ligamentous action so soon as they stoop. Hence 
they can go to sleep and not fall off the perch." ARTICULATIONS OF THE VERTEBRAL COLUMN 
269 
The articulations may be arranged into those of the trunk, those of the upper 
extremity, and those of the lower extremity. 
ARTICULATIONS OF THE TRUNK. 
These may be divided into the following groups, viz.: 
I. Of the vertebral column. 
II. Of the atlas with the axis. 
III. Of the atlas with the occipital 
bone. 
IV. Of the axis with the occipital bone. 
V. Of the lower jaw. 
VI. Of the ribs with the vertebrae. 
VIL Of the cartilages of the ribs with 
the sternum and with each other. 
VIII. Of the sternum. 
IX. Of the vertebral column with the 
pelvis. 
X. Of the pelvis. 
I. Articulations of the Vertebral Column. 
The different segments of the spine are connected together by spinal ligaments 
(ligamenta columnar vertebralis}, which may be divided into five sets: 1. d'hose 
connecting the bodies of the vertebrae. 2. Those connecting the laminae. 
3. Those connecting the articular processes. 4. Those connecting the spinous 
processes. 5. Those of the transverse processes. 
The articulations of the bodies of the vertebrae with each other form a series of 
amphiarthrodial joints; those between the articular processes form a series of 
arthrodial joints. 
1. The Ligaments of the Vertebral Bodies or Centra (Intercentral 
Ligaments). 
Anterior Common Ligament (anterior longitudinal ligament). 
Posterior Common Ligament (posterior longitudinal ligament). 
Intervertebral Substance (intervertebral disk, fi bro-cartilage). 
The Anterior Common or Anterior Longitudinal Ligament (ligamentum longitu- 
dinals anterius) (Figs. 197, 199, and 203) is a broad and strong band of longi- 
tudinal fibres which extends along the anterior (ventral) surface of the bodies of 
the vertebrae from the axis to the sacrum. It is broader below than above, thicker 
in the dorsal than in the cervical or lumbar regions, and somewhat thicker 
opposite the front of the body of each vertebra than opposite the intervertebral 
substance. It is attached, above, to the body of the axis by a pointed process, 
where it is continuous with the anterior atlanto-axial ligament, is connected 
with the tendon of insertion of the Longus colli muscle, and extends down as far 
as the upper bone of the sacrum. It consists of dense longitudinal fibres, which 
are intimately adherent to the intervertebral substance and the prominent margins 
of the vertebrae, but less closely to the middle of the bodies. In the latter 
situation the fibres are exceedingly thick, and serve to fill up the concavities 
on their front surface and to make the anterior surface of the spine more even. 
This ligament is composed of several layers of fibres, which vary in length, but 
are closely interlaced with each other. The most superficial or longest fibres 
extend between four or five vertebrae. A second subjacent set extends between 
two or three vertebrae, whilst a third set, the shortest and deepest, extends from 
one vertebra to the next. At the side of the bodies the ligament consists of a 
few short fibres, which pass from one vertebra to the next, separated from the 
median portion by large oval apertures for the passage of vessels. 270 
THE ARTICULATIONS OR JOINTS 
The Posterior Common or Posterior Longitudinal Ligament (ligamentum longi- 
tudinale poster ius) (Figs. 195, 197, 202, and 203) is situated within the spinal 
canal, and extends along the posterior (dorsal) surface of the bodies of the ver- 
tebrje from the body of the axis above, where it is continuous with the posterior 
INTERVERTE- 
BRAL FIBRO- 
CARTILAGE 
ROOT OF 
•VERTEBRAL 
ARCH 
Fig. 196.-Intervertebral disk, with the adjacent 
vertebral bodies, from in front. (Spalteholz.) 
occipito-axial ligament, to the sacrum 
below. It can be separated from the 
posterior occipito-axial ligament, as is 
shown in Fig. 203, and may be regarded 
as really arising from the clivus. It is 
broader above than below, and thicker in 
the dorsal than in the cervical or lumbar 
regions. In the situation of the intervertebral substance and contiguous margins 
of the vertebrae, where the ligament is more intimately adherent, it is broad, and 
presents a series of dentations with intervening concave margins; but it is narrow 
and thick over the centre of the bodies, from which it is separated by the venae 
basis vertebrae. This ligament is composed of smooth, shining, longitudinal 
fibres, denser and more compact than those of the anterior ligament, and formed 
of a superficial layer occupying the interval between three or four vertebrae, and 
of a deeper layer which extends between one vertebra and the next adjacent 
to it. It is separated from the dura mater of the spinal cord by some loose 
connective tissue, which is very liable to serous infiltration. 
The Intervertebral Fibro-cartilages, Disks, or Substances (fibrocartilagines inter- 
vertebrates') (Figs. 196 and 197).-Each fibrocartilaginous disk is of lenticular 
form and of composite structure. The disks are interposed between the adjacent 
surfaces of the bodies of the vertebrae from the axis to the sacrum, and form 
the chief bonds of connection between those bones. In young children inter- 
vertebral substance exists in the coccyx. These disks vary in shape, size, and 
thickness in different parts of the spine. In shape they accurately correspond 
with the surfaces of the bodies between which they are placed, being oval in the 
cervical and lumbar regions, and circular in the dorsal. Their size is greatest 
in the lumbar region. In thickness they vary not only in the different regions 
of the spine, but in different parts of the same disk: thus, they are thicker in 
front than behind in the cervical and lumbar regions, while they are uniformly 
thick in the dorsal region. The intervertebral disks form about one-fourth of 
the spinal column, exclusive of the first two vertebra?; they are not equally dis- 
tributed, however, between the various bones; the dorsal portion of the spine 
POSTERIOR COMMON 
LIGAMENT 
Fig. 195.-Vertebral bodies with ligaments, from 
behind. (Spalteholz.) ARTICULATIONS OF THE VERTEBRAL COLUMN 
271 
having, in proportion to its length, a much smaller quantity than in the cervical 
and lumbar regions, which necessarily gives to the latter parts greater pliancy 
and freedom of movement. The intervertebral disks are adherent, by their sur- 
faces, to a thin layer of hyaline cartilage which covers the upper and under sur- 
faces of the bodies of the vertebrae, and in which, in early life, the epiphysial 
plate develops, and by their circumference are closely connected in front to the 
anterior, and behind to the posterior common ligament; whilst in the dorsal 
region they are connected laterally, by means of the interarticular ligament, to 
the heads of those ribs which articulate with two vertebrae; they, consequentlv, 
form part of the articular cavities in which the heads of these bones are received. 
POSTERIOR COMMON 
LIGAMENT 
Fig. 197.-Median section of a piece of the lumbar spinal column, right half of sections viewed from the 
left. (Spalteholz.) 
Structure of the Intervertebral Substance.-The outer portion of the intervertebral 
substance is composed of many layers of fibrous connective tissue. This envel- 
oping portion is called the annulus fibrosus. The central portion of the disk is 
composed of soft, pulpy, highly elastic fibro-cartilage, containing some bands of 
connective tissue. It is called the nucleus pulposus, is of a yellowish color, and 
rises up considerably above the surrounding level when the disk is divided hori- 
zontally. This pulpy substance, which is especially well developed in the lumbar 
region, is the remains of the chorda dorsalis, and, according to Luschka, contains a 
small synovial cavity in its centre. The outer layers of the disk are arranged con- 
centrically one within the other, the outermost consisting of ordinary fibrous tissue, 
but the others and more numerous consisting of white fibro-cartilage. These 
plates are not quite vertical in their direction, those near the circumference being 
curved outward and closely approximated; whilst those nearest the centre curve 
in the opposite direction, and are somewhat more widely separated. The fibres of 
which each plate is composed are directed, for the most part, obliquely from above 
downward, the fibres of adjacent plates passing in opposite directions and varying 
in every layer; so that the fibres of one layer are directed across those of another, 
like the limbs of the letter X. This laminar arrangement belongs to about the 
outer half of each disk. The pulpy substance presents no concentric arrangement, 
and consists of a fine fibrous matrix, containing angular cells, united to form a 272 
THE ARTICULATIONS OR JOINTS 
reticular structure. J. Bland Sutton1 calls attention to the fact that in the human 
foetus a transverse ligamentous band crosses the dorsal aspect of the intervertebral 
disk and is continuous with the interosseous ligaments of the heads of the ribs; 
and also that a foetal ligamentous band exists in the ventral surface of the inter- 
vertebral disk which, after development, becomes the middle fasciculus of the 
stellate ligament. These bands are named by Sutton the posterior conjugal 
ligaments and the anterior conjugal ligaments. 
Interneural Articulations include the ligaments of the laminae; articular 
processes, spinous processes, and transverse processes. 
2. Ligaments connecting the Laminac. 
Ligamenta Subflava. 
The Ligamenta Subflava (ligamenta fava, ligamenta intercruralid) (Figs. 197 
and 198) are interposed between the laminae of the vertebrae, from the axis to 
the sacrum. They are most distinct when seen from the interior of the spinal 
canal; when viewed from the outer surface they appear short, being over- 
lapped by the laminae. Each ligamentum subflavum consists of two lateral 
portions, which commence on each side at the root of either articular process, 
and pass backward to the point where the laminae converge to form the spi- 
nous process, where their margins are in contact and to a certain extent united; 
slight intervals being left for the passage of small vessels. These ligaments 
consist of yellow elastic tissue, the 
fibres of which, almost perpendic- 
ular in direction, are attached to 
the anterior surface of the laminae 
above, some distance from its in- 
ferior margin, and to the posterior 
surface, as well as to the margin 
of the lamina below. In the cer- 
vical region they are thin in tex- 
ture, but very broad and long; 
they become thicker in the dorsal 
region, and in the lumbar acquire 
veryconsiderable thickness. Their 
highly elastic property serves to 
preserve the upright posture and 
to assist in resuming it after the 
spine has been flexed. These liga- 
ments do not exist between the 
occiput and atlas or between the 
atlas and axis. 
3. Ligaments connecting the 
Articular Processes. 
Capsular Ligaments. 
The Capsular Ligaments (capsula 
articulares) (Fig. 198) are thin and 
loose ligamentous sacs, attached 
to the contiguous margins of the articulating processes of each vertebra through 
the greater part of their circumference, and completed internally by the ligamenta 
Fig. 198.-Vertebral arches with ligamenta flava. 
(Spalteholz.) 
1 J. Bland Sutton. Ligaments: Their Nature and Morphology. ARTICULATIONS OF THE VERTEBRAL COLUMN 
273 
subflava. They are longer and looser in the cervical than in the dorsal or lumbar 
regions. The capsular ligaments are lined on their inner surface by synovial 
membrane. 
4. Ligaments connecting the Spinous Processes. 
Supraspinous Ligament. Interspinous Ligaments. 
The Supraspinous Ligament (ligamentum supraspinale) (Fig. 197) is a strong 
fibrous cord, which connects together the apices of the spinous processes from the 
seventh cervical to the spinous processes of the sacrum. It is thicker and broader 
in the lumbar than in the dorsal region, and intimately blended, in both situa- 
tions, with the neighboring aponeurosis. The most superficial fibres of this 
ligament connects three or four vertebra?; those deeper-seated pass between two 
or three vertebrae; whilst the deepest connect the contiguous extremities of 
neighboring vertebrae. It is continued upward to the external occipital protu- 
berance as the ligamentum nuchae, which, in the human subject, is thin and 
forms merely an intermuscular septum. 
The Interspinous Ligaments (ligamenta interspinalia) (Fig. 197), thin and 
membranous, are interposed between the spinous processes. Each ligament 
extends from the root to the summit of each spinous process and connects together 
their adjacent margins. They meet the ligamenta subflava in front and the 
supraspinous ligament behind. They are narrow and elongated in the dorsal 
region; broader, quadrilateral in form, and thicker in the lumbar region; and 
only slightly developed in the neck. 
5. Ligaments connecting the Transverse Processes. 
Intertransverse Ligaments. 
The Intertrans verse Ligaments (ligamenta intertransversaria) (Fig. 210) consist 
of bundles of fibres interposed between the transverse processes. In the cervical 
region they consist of a few irregular, scattered fibres; in the dorsal, they are 
rounded cords intimately connected with the deep muscles of the back; in the 
lumbar region they are thin and membranous. 
Actions.-The movements permitted in the spinal column are, flexion, exten- 
sion, lateral movement, circumduction, and rotation. 
In flexion (florward flexion), or movement of the spine forward, the anterior 
common ligament is relaxed, and the intervertebral substances are compressed 
in front, while the posterior common ligament, the ligamenta subflava, and the 
inter- and supra-spinous ligaments are stretched, as well as the posterior fibres 
of the intervertebral disks. The interspaces between the laminae are widened, 
and the inferior articular processes of the vertebrae above glide upward upon 
the articular processes of the vertebrae below. Flexion is the most extensive of 
all the movements of the spine. 
In extension (backward flexion), or movement of the spine backward, an exactly 
opposite disposition of the parts takes place. This movement is not extensive, 
being limited by the anterior common ligament and by the approximation of the 
spinous processes. 
Flexion and extension are free in the lower part of the lumbar region between 
the third and fourth and fourth and fifth lumbar vertebrae; above the third 
they are much diminished, and reach their minimum in the middle and upper 
part of the back. They increase again in the neck, the capability of motion 
backward from the upright position being in this region greater than that of the 
motion forward, whereas in the lumbar region the reverse is the case. 
In lateral flexion, the sides of the intervertebral disks are compressed, the 
extent of motion being limited by the resistance offered by the surrounding liga- 274 
THE ARTICULATIONS OR JOINTS 
ments and by the approximation of the transverse processes. This movement 
may take place in any part of the spine, but is most free in the neck and loins. 
Circumduction is very limited, and is produced merely by a succession of the 
preceding movements. 
Rotation is produced by the twisting of the intervertebral substances; this, 
although only slight between any two vertebra1, produces a considerable extent of 
movement when it takes place in the whole length of the spine, the front of the 
upper part of the column being turned to one or the other side. This movement 
takes place only to a slight extent in the neck, but is freer in the upper part of 
the dorsal region, and is altogether absent in the lumbar region. 
It is thus seen that the cervical region enjoys the greatest extent of each varietv 
of movement, flexion and extension especially being very free. In the dorsal 
region the three movements of flexion, extension, and circumduction are per- 
mitted only to a slight extent, while rotation is very free in the upper part and 
ceases below. In the lumbar region there is free flexion, extension, and lateral 
movement, but no rotation. 
As Sir George Humphry has pointed out, the movements permitted are mainly 
due to the shape and position of the articulating processes. In the loins the infe- 
rior articulating processes are turned outward and are embraced by the superior; 
this renders rotation in this region of the spine impossible, while there is nothing 
to prevent a sliding upward and downward of the surfaces on each other, so as to 
allow of flexion and extension. In the dorsal region, on the other hand, the 
articulating processes, by their direction and mutual adaptation, especially at the 
upper part of the series, permit of rotation, but prevent extension and flexion, 
while in the cervical region the greater obliquity and lateral slant of the articular 
processes allow not only flexion and extension, but also rotation. 
The principal muscles which produce flexion are the Sterno-mastoid, Rectus 
capitis anticus major, and Longus colli; the Scaleni; the abdominal muscles and 
the Psoas magnus. Extension is produced by the fourth layer of the muscles 
of the back, assisted in the neck by the Splenius, Semispinalis dorsi et colli, and 
the Multifidus spinie. Lateral motion is produced by the fourth layer of the 
muscles of the back, by the Splenius and the Scaleni, the muscles of one side only 
acting; and rotation by the action of the following muscles of one side only-viz. 
the Sterno-mastoid, the Rectus capitis anticus major, the Scaleni, the Multifidus 
spinie, the Complexus, and the abdominal muscles. 
II. Articulation of the Atlas with the Axis (Articulatio Atlantoepistrophica). 
The articulation of the atlas with the axis is of a complicated nature, compris- 
ing no fewer than four distinct joints. There is a pivot articulation between the 
odontoid process of the axis and the ring formed between the anterior arch of the 
atlas and the transverse ligament (see Fig. 201). Here there are two joints: one in 
front between the posterior surface of the anterior arch of the atlas and the front 
of the odontoid process, the atlanto-odontoid joint of Cruveilhier; the other between 
the anterior surface of the transverse ligament and the back of the process, the 
syndesmo-odontoid joint. Between the articular processes of the two bones there 
is a double arthrodia or gliding joint. The ligaments which connect these bones 
are the 
Anterior Atlanto-axial. 
Posterior Atlanto-axial. 
Transverse. 
Two Capsular. 
The Anterior Atlanto-axial or the Anterior Atlo-axoid Ligament (Figs. 199 and 203) 
is a strong, membranous layer, attached, above, to the lower border of the anterior 
arch of the atlas; below, to the base of the odontoid process and to the front of ARTICULATION OF THE ATLAS WITH THE AXIS 
275 
the body of the axis. It is strengthened in the middle line by a rounded cord, which 
is attached, above, to the tubercle on the anterior arch of the atlas, and below to 
the body of the axis, being a continuation upward of the anterior common liga- 
ment of the spine. Some anatomists regard this ligament as being a part of the 
anterior common ligament. The ligament is in relation, in front, with the Recti 
antici majores. 
The Posterior Atlanto-axial or the Posterior Atlo-axoid Ligament (Figs. 200 and 
203) is a broad and thin membranous layer, attached, above, to the lower border 
of the posterior arch of the atlas; below, to the upper edge of the laminae of 
the axis. This ligament supplies the place of the ligamenta subflava, and is 
in relation, behind, with the Inferior oblique muscles. 
The Transverse Ligament of the Atlas1 (ligamentum transversum atlantis) (Figs. 
201, 202, and 203) is a thick, strong band, which arches across the ring of the 
atlas, and serves to retain the odontoid process in firm connection with its anterior 
arch. This ligament is flattened from before backward, broader and thicker in 
the middle than at either extremity, and firmly attached on each side to a small 
tubercle on the inner surface of the lateral mass of the atlas. As it crosses the 
odontoid process, a small fasciculus is derived from its upper, and another from 
its lower, border; the former passing upward, to be inserted into the anterior sur- 
PHARYNGEAL 
TUBERCLE 
BASILAR PORTION OF 
OCCI PITAL BONE 
ANTERIOR OCCIPITO- 
ATLANTAL LIGAMENT 
ANTERIOR CONDYLOID 
FORAMEN 
CAPSULAR. 
LIGAMENT 
OCC I PITO-ATLANTAL 
"articulation 
TRANSVERSE 
-PROCESS OF 
ATLAS 
CAPSULAR 
LIGAMENT* 
-ANTERIOR ATLANTO- 
AXIAL LIGAMENT 
TRANSVERSE 
-PROCESS OF 
AXIS 
JOINT BETWEEN! 
BODY OF VERTEBRA 
AND INTERVER-. 
TEBRAL FIBRO- 
CARTILAGE 
TRANSVERSE PROCESS 
.OFTHIRD CERVICAL 
VERTEBRA 
INTERVERTEBRAL 
Fl BROCA RTI LAGE 
ANTERIOR COMMON 
LIGAMENT 
Fig. 199.-Occipital bone and first three cervical vertebrae with ligaments, from in front. (Spalteholz.) 
face of the foramen magnum of the occipital bone; the latter, downward, to be 
attached to the posterior surface of the body of the axis; hence, the whole ligament 
has received the name of cruciform ligament (ligamentum cruciatum atlantis). 
A synovial surface is interposed between the odontoid process and the trans- 
verse ligament, and one is placed between the anterior surface of the odontoid 
process and the anterior arch of the atlas. The transverse ligament divides the 
1 It has been found necessary to describe the transverse ligament with those of the atlas and axis; but the 
student must remember that it is really a portion of the mechanism by which the movements of the head on the 
spine are regulated; so that the connections between the atlas and axis ought always to be studied together with 
those between the latter bones and the skull. THE ARTICULATIONS OR JOINTS 
276 
ring of the atlas into two unequal parts: of these, the posterior and larger serves 
for the transmission of the cord and its membranes and the spinal accessory 
nerves; the anterior and smaller contains the odontoid process. Since the space 
between the anterior arch of the atlas and the transverse ligament is smaller at 
the lower part than the upper (because the transverse ligament embraces tightly 
the narrow neck of the odontoid process), this process is retained in firm connec- 
tion with the atlas after all the other ligaments have been divided. 
The Capsular Ligaments (capsules articulares) (Figs. 199, 200, and 202) are two 
thin and loose capsules, connecting the lateral masses of the atlas with the superior 
articular surfaces of the axis, the fibres being strengthened at the posterior and 
inner part of each articulation by an accessory ligament, which is attached below 
to the body of the axis near the base of the odontoid process. 
Synovial Membranes (Fig. 201).-There are jour synovial membranes in this 
articulation: one lining the inner surface of each of the capsular ligaments; one 
between the anterior surface of the odontoid process and the anterior arch of 
the atlas, the atlanto-odontoid joint; and one between the posterior surface of 
the odontoid process and the transverse ligament, the syndesmo-odontoid joint. 
The latter often communicates with those between the condyles of the occipital 
bone and the articular surfaces of the atlas. 
Actions.-This joint allows the rotation of the atlas (and, with it, of the cra- 
nium) upon the axis, the extent of rotation being limited by the odontoid ligaments. 
The principal muscles by which this action is produced are the Sterno-mastoid 
and Complexus of one side, acting with the Rectus capitis anticus major, Sple- 
nius, Trachelo-mastoid, Rectus capitis posticus major, and Inferior oblique of the 
other side. 
ARTICULATIONS OF THE SPINE WITH THE CRANIUM. 
The ligaments connecting the spine with the cranium may be divided into two 
sets-those connecting the occipital bone with the atlas, and those connecting the 
occipital bone with the axis. 
III. Articulation of the Atlas with the Occipital Bone (Articulatio 
Atlantooccipitalis). 
This articulation is a double condyloid joint. Its ligaments are the 
Anterior Occipito-atlantal. Posterior Occipito-atlantaL 
Two Capsular. 
The Anterior Occipito-atlantal Ligament or Membrane (membrana atlantooccipitalis 
anterior, anterior occipito-atloid ligament) (Figs. 199 and 203) is a broad membra- 
nous layer, composed of densely woven fibres, which passes between the anterior 
margin of the foramen magnum above, and the whole length of the upper border 
of the anterior arch of the atlas below. Laterally, it is continuous with the cap- 
sular ligaments. In the middle line in front it is strengthened by a strong, narrow, 
rounded cord, which is attached, above, to the basilar process of the occiput, and, 
below, to the tubercle on the anterior arch of the atlas, and which is a continua- 
tion of the anterior common ligament. This ligament is in relation, in front, 
with the Recti antici minores; behind, with the odontoid ligaments. 
The Posterior Occipito-atlantal Ligament or Membrane {membrana atlantooccipitalis 
posterior, posterior occipito-atloid ligament) (Figs. 200 and 20.3) is a very broad but 
thin membranous lamina intimately blended with the dura mater. It is connected, 
above, to the posterior margin of the foramen magnum; below, to the upper border ARTICULATION OF THE ATLAS WITH THE OCCIPITAL BONE 
277 
of the posterior arch of the atlas. This ligament is incomplete at each side, and 
forms, with the superior intervertebral notch, an opening for the passage of the 
vertebral artery and suboccipital nerve. The fibrous band which arches over the 
artery and nerve sometimes becomes ossified. The ligaments are in relation, 
behind, with the Recti postici minores and Obliqui superiores; in front, with the 
dura mater of the spinal canal, to which they are intimately adherent. 
POSTERIOR OC- 
Cl PITO-ATLANTAL' 
LIGAMENT 
TRANSVERSE 
PROCESS OF 
ATLAS 
POSTERIOR OC- 
CIPITO-ATLANTAL 
LIGAMENT 
TRANSVERSE 
'PROCESS OF 
AXIS 
POSTERIOR 
ATLANTOAXIAL** 
LIGAMENT 
Fig. 200.-Occipital bone, first and second cervical vertebrae with ligaments from behind. (Spalteholz.) 
The Capsular Ligaments (capsuloe articulares) (Fig. 202) surround the condyles 
of the occipital bone, and connect them with the articular processes of the atlas; 
they consist of thin and loose capsules, which enclose the synovial membranes 
of the articulations. 
Synovial Membranes.-There are two synovial membranes in this articulation, 
one lining the inner surface of each of the capsular ligaments. These occasionally 
communicate with that between the posterior surface of the odontoid process and 
the transverse ligament. 
For Spinal Cord and 
its Membranes. 
Fig. 201.-Articulation between odontoid process and atlas. 
Actions.-The movements permitted in this joint are flexion and extension, 
which give rise to the ordinary forward and backward nodding of the head. Slight 
lateral motion to one or the other side may also take place. When either of these 
actions is carried beyond a slight extent, the whole of the cervical portion of the spine 
assists in its production. Flexion is mainly produced by the action of the Rectus 
capitis anticus major et minor and the Sterno-mastoid muscles; extension by the 278 
THE ARTICULATIONS OR JOINTS 
Rectus capitis posticus major et minor, the Superior oblique, the Coinplexus, Sple- 
nius, and upper fibres of the Trapezius. The Recti laterales are concerned in the 
lateral movement, assisted by the Trapezius, Splenitis, Complexus, and the Sterno- 
mastoid of the same side, all acting together. According to Cruveilhier, there is 
a slight motion of rotation in this joint. 
IV. Articulation of the Axis with the Occipital Bone. 
The ligaments of this articulation are the 
Occipito-axial. Three Odontoid. 
To expose these ligaments the spinal canal should be laid open by removing 
the posterior arch of the atlas, the laminae and spinal process of the axis, and the 
portion of the occipital bone behind the foramen magnum, as seen in Fig. 192. 
The Posterior Occipito-axial Ligament (posterior occipito-axoid ligament, membrana 
tectoria, apparatus ligamentosus colli) (Figs. 202 and 203) is situated within the spinal 
canal. It is a broad, strong band, which covers the odontoid process and its liga- 
ments, and appears to be a prolongation upward of or a membrane due to fusion 
with the posterior common ligament of the spine. It is attached, below, to the 
posterior surface of the body of the axis, and, becoming expanded as it ascends, 
is inserted into the basilar groove of the occipital bone, in front of the foramen 
magnum, where it becomes blended with the dura mater of the skull. 
occipito-axoid ligament, divided and turned back. 
The vertical portion of 
ODONTOID LIGAMENTS. 
OCCIPITO 
ATLANTAL 
CAPSULAR LIGAMENT 
and synovial 
membrane. 
ATLANTO- 
AXIAL 
CAPSULAR LIGAMENT 
and synovial 
membrane. 
Fig. 202.-Occipito-axial and atlanto-axial ligaments. Posterior view, obtained by removing the arches of 
the vertebrae and the posterior part of the skull. 
Relations.-By its anterior surface with the transverse ligament; by its posterior 
surface with the posterior common ligament. 
The Lateral Odontoid or Check Ligaments (ligamenta alarid) (Figs. 202 and 203) 
are strong, rounded, fibrous cords, which arise one on either side of the upper 
part of the odontoid process, and, passing obliquely upward and outward, are 
inserted into the rough depressions on the inner side of the condyles of the ARTICULATION OF THE AXIS WITH THE OCCIPITAL BONE 
279 
occipital bone. In the triangular interval left between these ligaments another 
strong fibrous cord, ligamentum suspensorium, or middle odontoid ligament (liga- 
mentum apicis dentis), may be seen, which passes almost perpendicularly from 
the apex of the odontoid process to the anterior margin of the foramen mag- 
num, being intimately blended with the deep portion of the anterior occipito- 
atlantal ligament and upper fasciculus of the transverse ligament of the atlas. 
Actions.-The odontoid ligaments serve to limit the extent to which rotation 
of the cranium may be carried; hence, they have received the name of check 
ligaments. 
In addition to these ligaments, which connect the atlas and axis to the skull, 
the ligamentum nuchse must be regarded as one of the ligaments by which the 
spine is connected with the cranium. It is described on page 273. 
Surgical Anatomy.-The ligaments which unite the component parts of the vertebrae 
together are so strong, and these bones are so interlocked by the arrangement of their articu- 
lating processes, that dislocation is very uncommon, and, indeed, unless accompanied by fracture, 
seldom occurs, except in the upper part of the neck. Dislocation of the occiput from the atlas 
THIN LAYER OF POSTERIOR COMMON 
LIGAM ENT SEPARATED FROM THE 
POSTERIOR OCCIPITO-AXIAL LIGAMENT 
HYPOGLOSSAL 
NERVE 
ANTERIOR OCCIPITO-- 
ATLOID LIGAMENT 
POSTERIOR OCCIPITO- 
AXIAL LIGAMENT 
CRUCIFORM . 
LIGAM ENT 
MIDDLE ODONTOID. 
LIGAMENT 
ANTERIOR ARCH. 
OF ATLAS 
.POSTERIOR OCCIP- 
ITO- ATLANTAL 
LIGAMENT 
ODONTOID PROC- 
ESS OF AXIS 
ARTICULAR 
cavity' 
POSTERIOR 
-ARCH OF 
ATLAS 
TRANSVERSE LIGA- 
MENT OF ATLAS 
ANTERIOR ATLO- 
AXOID LIGAMENT 
SUBOCCIPITAL 
NERVE 
-INTERVERTE- 
BRAL FORAMEN 
FNTERVERTEBRAL 
Fl B RO-CA RTI LAGE 
ANTERIOR COMMON 
LIGAMENT' 
POSTERIOR COMMON 
LIGAMENT 
Fig. 203.-Median section through the occipital bone and first three cervical vertebrae with ligaments. 
(Spalteholz.) 
has only been recorded in one or two cases; but dislocation of the atlas from the axis, with rup- 
ture of the transverse ligament, is much more common: it is the mode in which death is produced 
in many cases of execution by hanging. Occipito-atloid dislocation is certainly fatal. Recoveries 
are on record after atlo-axoid dislocation. Immediate death occurs if the transverse ligament 
is torn or the odontoid process is broken. In the lower part of the neck-that is, below the 
third cervical vertebra-dislocation unattended by fracture occasionally takes place. 280 
THE ARTICULATIONS OR JOINTS 
V. Articulation of the Lower Jaw, or the Temporo-mandibular Articulation 
(Articulatio Mandibularis). 
This is a ginglymo-arthrodial joint: the parts entering into its formation on 
each side are, above, the anterior part of the glenoid cavity of the temporal bone 
and the eminentia articularis; and, below, the condyle of the lower jaw. The 
ligaments are the following: 
o o 
External Lateral. 
Internal Lateral. 
Stylo-mandibular. 
Capsular. 
Interarticular Fibro-cartilage. 
The External Lateral Ligament (ligamentum temporo mandibular e) (Fig. 204) is a 
short, thin, and narrow fasciculus, attached, above, to the outer surf ace of the zygoma 
and to the tubercle on its lower border; below, to the outer surface and posterior 
border of the neck of the lower jaw. It is broader above than below; its fibres are 
Temporal bone. 
Inferior 
maxilla. 
Fig. 204.-Temporomandibular articulation. 
placed parallel with one another, and directed obliquely downward and backward. 
Externally, it is covered by the parotid gland and by the integument. Internally 
it is in relation with, the capsular ligament, of which it is an accessory band, and 
from which it is not separable. 
The Internal Lateral Ligament (ligamentum sphenomandibulare) (Fig. 205) is a 
flat, thin band which is attached above to the spinous process of the sphenoid 
bone, and, becoming broader as it descends, is inserted into the margin of the 
mandibular or dental foramen and the portion of bone, the lingula, which over- 
hangs the foramen in front. Its outer surface is in relation, above, with the 
External pterygoid muscle; lower down it is separated from the neck of the 
condyle by the internal maxillary artery; and still more inferiorly, the inferior 
dental vessels and nerve separate it from the ramus of the jaw. The inner surface 
is in relation with the Internal pterygoid. It is really the fibrous covering of a 
part of Meckel's cartilage. ARTICULATION OF THE LOWER JAW 
281 
The Stylo-mandibular or Stylo-maxillary Ligament (ligamentum stylomandibulare) 
(Fig. 205) is a specialized band of the cervical fascia, which extends from near the 
apex of the styloid process of the temporal bone to the angle and posterior border 
of the ramus of the lower jaw, between the Masseter and Internal pterygoid mus- 
cles. This ligament separates the parotid from the submaxillary gland, and has 
attached to its inner side part of 
the fibres of origin of the Stylo- 
glossus muscle. Although usually 
classed among the ligaments of the 
jaw, it can be considered only as 
an accessory to the articulation. 
The Capsular Ligament (capsula 
articularis) (Figs. 204 and 205) 
forms a thin and loose capsule, 
passing from the circumference of 
the glenoid cavity and the articular 
surface immediately in front to the 
upper margin of the articular disk, 
and from the lower margin of the 
articular disk to the neck of the 
condyle of the lower jaw. It con- 
sists of very thin fibres, and is com- 
plete. It forms two joint cavities, 
distinct from each other, and sepa- 
rated by the articular disk. So 
thin is it that it is hardly to be 
considered as a distinct ligament; it is thickest at the back part, and thinnest 
on the inner side of the articulation.1 
1 he Interarticular Fibro-cartilage or Meniscus (discus articularis} (Fig. 206) is a 
thin plate of an oval form, placed horizontally between the condyle of the jaw and 
the glenoid cavity. Its upper surface 
is concavo-convex from before back- 
ward, and a little convex transversely, 
to accommodate itself to the form of 
the glenoid cavity. Its under surface, 
where it is in contact with the con- 
dyle, is concave. Its circumference is 
connected to the capsular ligament, 
and in front to the tendon of the Ex- 
ternal pterygoid muscle. It is thicker 
at its circumference, especially be- 
hind, than at its centre. The fibres 
of which it is composed have a con- 
centric arrangement, more apparent 
at the circumference than at the 
centre. Its surfaces are smooth. It divides the joint into two cavities, each 
of which is furnished with a separate synovial membrane from the capsular 
ligament. 
Synovial Membranes (Fig. 206).-The synovial membranes, two in number, are 
placed, one above, and the other below, the fibro-cartilage. The upper one, the 
larger and looser of the two, is continued from the margin of the cartilage covering 
Fig. 205.-Temporo-mandibular articulation. Internal view 
Fig. 206.-Vertical section of temporo-mandibular 
articulation. 
1 Sir G. Humphry describes the internal portion of the capsular ligament separately as the short internal lateral 
ligament: and it certainly seems as deserving of a separate description as is the external lateral ligament. 282 
THE ARTICULATIONS OR JOINTS 
the glenoid cavity and eminentia articularis on to the upper surface of the fibro- 
cartilage. The lower one passes from the under surface of the fibro-cartilage to 
the neck of the condyle of the jaw, being prolonged downward a little farther 
behind than in front. The interarticular cartilage is sometimes perforated in its 
centre; the two synovial sacs then communicate with each other. 
The nerves of this joint are derived from the auriculo-temporal and masseteric 
branches of the inferior maxillary. The arteries are derived from the temporal 
branch of the external carotid. 
Actions.-The movements possible in this articulation are very extensive. 'Thus, 
the jaw may be depressed or elevated, or it may be carried forward or backward. 
It must be borne in mind that there are two distinct joints in this articula- 
tion-that is to say, one between the condyle of the jaw and the interarticular 
fibro-cartilage, and another between the fibro-cartilage and the glenoid fossa; 
when the jaw is depressed, as in opening the mouth, the movements which take 
place in these two joints are not the same. In the lower compartment, that between 
the condyle and the fibro-cartilage, the movement is of a ginglymoid or hinge-like 
character, the condyle rotating on a transverse axis on the fibro-cartilage; while in 
the upper compartment the movement is of a gliding character, the fibro-cartilage, 
together with the condyle, gliding forward on to the eminentia articularis. These 
two movements take place simultaneously-the condyle and fibro-cartilage move 
forward on the eminence, and at the same time the condyle revolves on the fibro- 
cartilage. In the opposite movement of shutting the mouth the reverse action takes 
place; the fibro-cartilage glides back, carrying the condyle with it, and this at the 
same time revolves back to its former position. When the jaw is carried horizon- 
tally forward, as in protruding the lower incisors in front of the upper, the move- 
ment takes place principally in the upper compartment of the joint: the fibro- 
cartilage, carrying with it the condyle, glides forward on the glenoid fossa. This 
is because this movement is mainly effected by the External pterygoid muscles, 
which are inserted into both condyle and interarticular fibro-cartilage. The grind- 
ing or chewing movement is produced by the alternate movement of one condyle, 
with its fibro-cartilage, forward and backward, while the other condyle moves 
simultaneously in the opposite direction; at the same time the condyle undergoes a 
vertical rotation on its own axis on the fibro-cartilage in the lower compartment. 
One condyle advances and rotates, the other condyle recedes and rotates, in alter- 
nate succession. 
The lower jaw is depressed by its own weight, assisted by the Platysma, the 
Digastric, the Mylo-hyoid, and the Genio-hyoid muscles. It is elevated by the 
anterior part of the Temporal, Masseter, and Internal pterygoid. It is drawn for- 
ward by the simultaneous action of the External pterygoid and the superficial fibres 
of the Masseter; and it is drawn backward by the deep fibres of the Masseter and 
the posterior fibres of the Temporal muscle. The grinding movement is caused by 
the alternate action of the two External pterygoids. 
Surface Form.-The temporomandibular articulation is quite superficial, situated below the 
base of the zygoma, in front of the tragus and external auditory meatus, and behind the poste- 
rior border of the upper part of the Masseter muscle. Its exact position can be at once ascer- 
tained by feeling for the condyle of the jaw, the working of which can be distinctly felt in the 
movements of the lower jaw in opening and shutting the mouth. When the mouth is opened 
wide, the condyle advances out of the glenoid fossa on to the eminentia articularis, and a depres- 
sion is felt in the situation of the joint. 
Surgical Anatomy.-Genuine dislocation of the lower jaw is always forward. Croker, 
King, and Theim, however, have reported posterior displacement. Dislocation is caused by 
violence or muscular action. When the mouth is open, the condyle is situated on the eminentia 
articularis, and any sudden violence, or even a sudden muscular spasm, as during a convulsive 
yawn, may displace the condyle forward into the zygomatic fossa. The displacement may be 
unilateral or bilateral, according as one or both of the condyles are displaced. The latter of ARTICULATIONS OF THE RIBS WITH THE VERTEBRAE 
283 
the two is the more common. The interarticular fibro-cartilage adheres to the condyle till it 
passes over the eminentia articularis, but at this point remains behind. 
Sir Astley Cooper described a condition which he termed " subluxation." It occurs princi- 
pally in delicate women, and is believed by some to be due to the relaxation of the ligaments, 
permitting too free movement of the bone. Others believe it is due to displacement of the inter- 
articular fibro-cartilage. Still others attribute the symptoms to gouty or rheumatic changes in 
the joint. In close relation to the condyle of the jaw' is the external auditory meatus and the 
tympanum; any force, therefore, applied to the bone is liable to be attended with damage to 
these parts, or inflammation in the joint may extend to the ear, or on the other hand inflam- 
mation of the middle ear may involve the articulation and cause its destruction, thus leading 
to ankylosis of the joint. In children, arthritis of this joint may follow the exanthemata, and 
in adults it occurs as the result of some constitutional conditions, as rheumatism or gout. The 
temporo-mandibular joint is also occasionally the seat of osteo-arthritis, leading to great suffer- 
ing during efforts of mastication. A peculiar affection sometimes attacks the neck and condyle 
of the lower jaw, consisting in hypertrophy and elongation of these parts and consequent protru- 
sion of the chin to the opposite side. 
VI. Articulations of the Ribs with the Vertebrae or the Costo-vertebral 
Articulations (Articulationes Costovertebrales). 
The articulations of the ribs with the vertebral column may be divided into 
two sets: 1. Those which connect the heads of the ribs with the bodies of the 
vertebrae; costo-central. 2. Those which connect the necks and tubercles of the 
ribs with the transverse processes; costo-transverse. 
1. Articulations between the Heads of the Ribs and the Bodies of 
the Vertebrae or the Costo-central Articulations (Articu- 
lationes Capitulorum) (Figs. 207 and 208). 
These constitute a series of arthrodial joints, formed by the articulation of the 
heads of the ribs with the cavities on the contiguous margins of the bodies of the 
FOVEA COSTALIS 
TRANSVERSALIS 
ANTERIOR 
COSTOTRANS- 
VERSE LIGAMENT 
INTERVERTEBRAL 
^Fl B ROC A RTI LAG E 
Fig. 207.-Spinal column with ligament, from in front. (Spalteholz.) 284 
THE ARTICULATIONS OR JOINTS 
dorsal vertebrae and the intervertebral substance between them, except in the case 
of the first, tenth, eleventh, and twelfth ribs, where the cavity is formed by a single 
vertebra. The bones are connected by the following ligaments: 
Anterior Costo-vertebral or Stellate. 
Capsular. Interarticular. 
The Anterior Costo-vertebral or Stellate Ligament (ligamentum capituli costoe radi- 
atum) (Figs. 207 and 210) connects the anterior part of the head of each rib with the 
sides of the bodies of two vertebne and the intervertebral disk between them. It 
consists of three flat bundles of ligamentous fibres, which are attached to the ante- 
rior part of the head of the rib, just beyond the articular surface. The superior 
fibres pass upward to be con- 
nected with the body of the 
vertebra above; the inferior 
one descends to the body of 
the vertebra below; and the 
middle one, the smallest and 
least distinct, passes horizon- 
tally inward, to be attached 
to the intervertebral sub- 
stance. 
Relations.-In front, with 
the thoracic ganglia of the 
sympathetic, the pleura, and, 
on the right side, with the vena 
azygos major; behind, with 
the interarticular ligament 
and synovial membranes. 
On the first rib, which 
articulates with a single ver- 
tebra, this ligament does not 
present a distinct division 
into three fasciculi; its fibres, 
however, radiate, and are at- 
tached to the body of the last cervical vertebra, as well as to the body of the 
vertebra with which the rib articulates. In the tenth, eleventh, and twelfth ribs 
also, which likewise articulate with a single vertebra, the division does not exist; 
but the fibres of the ligament in each case radiate and are connected with the 
vertebra above, as well as that with which the ribs articulate. 
The Capsular Ligament (capsula articularis) is a thin and loose ligamentous bag, 
which surrounds the joint between the head of the rib and the articular cavity 
formed by the intervertebral disk and the adjacent vertebra. It is very thin, 
firmly connected with the anterior ligament, and most distinct at the upper and 
lower parts of the articulation. Behind, some of its fibres pass through the inter- 
vertebral foramen to the back of the intervertebral disk. This is the analogue of 
the ligamentum conjugale of some mammals, which unites the heads of opposite 
ribs across the back of the intervertebral disk. 
The Interarticular Ligament (ligamentum capituli costoe interarticular e} (Figs. 208 
and 209) is situated in the interior of the joint. It consists of a short band of 
fibres, flattened from above downward, attached by one extremity to the sharp 
crest which separates the two articular facets on the head of the rib, and by the 
other to the intervertebral disk. It divides the joint into two cavities, which 
have no communication with each other. In the first, tenth, eleventh, and 
INTERARTICULAR liga- 
ment OF HEAD OF RIB 
Fig. 208.-Ribs and corresponding vertebral bodies with their 
ligaments, viewed from the right. (Spalteholz.) ARTICULATIONS OF THE RIBS WITH THE VERTEBRAE 
285 
twelfth ribs the interarticular ligament does not exist; consequently there is but 
one synovial membrane. 
Synovial Membranes (Figs. 208 and 209).-There are two synovial membranes 
in each of the articulations in which there is an interarticular ligament, one on 
each side of this structure. 
2. Articulations of the Necks and Tubercles of the Ribs with the 
Transverse Processes or the Costo-transverse Articulations 
(Articulationes Costotransversarle) (Fig. 209). 
The articular portion of the tubercle of the rib and adjacent transverse process 
form an arthrodial joint. 
In the eleventh and twelfth ribs this articulation is wanting. 
The ligaments connecting these parts are the 
Anterior Superior Costo-transverse. 
Middle Costo-transverse (Interosseous). 
Posterior Costo-transverse 
Capsular. 
The Anterior Superior or Long Costo-transverse Ligament (ligamentum costo- 
transversarium ant er ins) (Figs. 207,208,209, and 210) consists of two sets of fibres: 
the one (anterior) is attached below to the sharp crest on the upper border 
INTERARTICULAR 
LIGAMENT 
SYNOVIAL 
MEMBRANE 
ANTERIOR COSTO-TRANSVERSE 
LIGAMENT DIVIDED. 
MIDDLE COSTO-TRANSVERSE 
CT INTEROSSEOUS. 
POSTERIOR COSTO- 
TRANSVERSE LIGAMENT. 
Vertebral 
Foramen. 
SYNOVIAL CAVITY. 
CAPSULAR MEMBRANE. 
Fig. 209.-Costo-transverse articulation. Seen from above. 
of the neck of each rib, and passes obliquely upward and outward to the lower 
border of the transverse process immediately above; the other (posterior) is 
attached below to the neck of the rib, and passes upward and inward to the base 
of the transverse process and outer border of the lower articular process of the 
vertebra above. This ligament is in relation, in front, with the intercostal vessels 
and nerves; behind, with the Longissimus dorsi muscle. Its internal border is 
thickened and free, and bounds an aperture through which pass the posterior 
branches of the intercostal vessels and nerves. Its external border is continuous 
with a thin aponeurosis which covers the External intercostal muscle. 
The first rib has no anterior costo-transverse ligament. In the twelfth rib the 
ligament is absent or is a mere vestige. 286 
THE ARTICULATIONS OR JOINTS 
The Middle Costo-transverse or Interosseous Ligament (lig amentum colli costoe) 
(Fig. 209) consists of short but strong fibres which pass between the rough sur- 
face on the posterior part of the neck of each rib and the anterior surface of the 
adjacent transverse process. In order fully to expose this ligament, a horizontal 
section should be made across the transverse process and corresponding part of 
the rib; or the rib may be forcibly separated from the transverse process and the 
fibres of the ligament put on the stretch. 
In the eleventh and twelfth ribs this ligament is quite rudimentary or wanting. 
The Posterior Costo-transverse Ligament (ligamentumcostotransversarium posterius) 
(Fig. 209) is a short but thick and strong fasciculus which passes obliquely from the 
summit of the transverse 
process to the rough non- 
articular portion of the 
tubercle of the rib. This 
ligament is shorter and 
more oblique in the upper 
than in the lower ribs. 
Those corresponding to 
the superior ribs ascend, 
while those of the inferior 
ribs descend slightly. 
In the eleventh and 
twelfth ribs this ligament 
is wanting. 
The Capsular Ligament 
(capsula articular is) is a 
thin, membranous sac at- 
tached to the circumfer- 
ence of the articulari sur- 
faces, and enclosing a 
small synovial membrane. 
In the eleventh and 
twelfth ribs this ligament 
is absent. 
Actions.-The heads of 
the ribs are so closely 
connected to the bodies 
of the vertebrae by the 
stellate and interarticular 
ligaments, and the necks 
and tubercles of the ribs to the transverse processes, that only a slight sliding 
movement of the articular surfaces on each other can take place in these articula- 
tions. The result of this gliding movement with respect to the six upper ribs con- 
sists in an elevation of the front and middle portion of the rib, the hinder part 
being prevented from performing any upward movement by its close connection 
with the spine. In this gliding movement the rib rotates on an axis corresponding 
with a line drawn through the two articulations, costo-central and costo-transverse, 
which the rib forms with the spine. With respect to the seventh, eighth, ninth, and 
tenth ribs, each one, besides rotating in a similar manner to the upper six, also 
rotates on an axis corresponding with a line drawn from the head of the rib to the 
sternum. By the first movement-that of rotation of the rib on an axis correspond- 
ing with a line drawn through the two articulations which this bone forms with 
the spine-an elevation of the anterior part of the rib takes place, and a consequent 
enlargement of the antero-posterior diameter of the chest. None of the ribs lie in 
ARTICULAR SURFACE 
FOR TUBERCLE 
OF RIB 
SUPERIOR ARTICULAR 
SURFACE FOR HEAD 
OF RIB 
ANTERIOR 
COSTO-TRANS- 
VERSE LIGAMENT- 
INTERTRANS- 
VERSE LIGAMENT' 
INTERVERTE- 
•BRAL FIBRO- 
CARTILAGE 
INFERIOR ARTICULAR 
SURFACE FOR HEAD 
OF RIB 
I N FERIOR ARTIC- 
ULAR PROCESS 
F,G 210,-Rib. ™wed ARTICULATION OF CARTILAGES OF RIBS WITH STERNUM 
287 
a truly horizontal plane; they are all directed more or less obliquely, so that their 
anterior extremities lie on a lower level than their posterior, and this obliquity 
increases from the first to the seventh, and then again decreases. If we examine 
any one rib-say, that in which there is the greatest obliquity-we shall see that 
it is obvious that as its sternal extremity is carried upward, it must also be thrown 
forward; so that the rib may be 
regarded as a radius moving on 
the vertebral joint as a centre, and 
causing the sternal attachment to 
describe an arc of a circle in the 
vertical plane of the body. Since 
all the ribs are oblique and con- 
nected in front to the sternum by 
the elastic costal cartilages, they 
must have a tendency to thrust 
the sternum forward, and so in- 
crease the antero-posterior diam- 
eter of the chest. By the second 
movement-that of the rotation 
of the rib on an axis correspond- 
ing with a line drawn from the 
head of the rib to the sternum- 
an elevation of the middle portion 
of the rib takes place, and conse- 
quently an increase in the trans- 
verse diameter of the chest. For 
the ribs not only slant downward 
and forward from their vertebral 
attachment, but they are also ob- 
lique in relation to their transverse 
plane-that is to say, their middle 
is on a lower level than either 
their vertebral or sternal extremi- 
ties. It results from this that when 
the ribs are raised, the centre por- 
tion is thrust outward, somewhat 
after the fashion in which the 
handle of a bucket is thrust away 
from the side when raised to a 
horizontal position, and the lateral 
diameter of the chest is increased 
(see Fig. 211). The mobility of the different ribs varies very much. The first rib 
is more fixed than the others, on account of the weight of the upper extremity and 
the strain of the ribs beneath; but on the freshly dissected thorax it moves as freely 
as the others. From the same causes the movement of the second rib is also not 
very extensive. In the other ribs this mobility increases successively down to the 
last two, which are very movable. The ribs are generally more movable in the 
female than in the male. 
a A 
B 
A 
Fig. 211.-Diagrams showing the axis of rotation of the 
ribs in the movements of respiration. The one axis of rota- 
tion corresponds with the line drawn through the two articu- 
lations which the rib forms with the spine (a, b), and the other 
with a line drawn from the head of the rib to the sternum 
(A, B). (From Kirke's Handbook of Physiology.) 
VII. Articulation of the Cartilages of the Ribs with the Sternum, etc., or 
the Costo-sternal Articulations (Articulationes 
Sternocostales) (Fig. 212). 
The articulations of the cartilages of the true ribs with the sternum are arthro- 
dial joints, with the exception of the first, in which the cartilage is almost always 288 
THE ARTICULATIONS OR JOINTS 
directly united with the sternum, and which must therefore be regarded as a 
synarthrodial articulation. The ligaments connecting them are the 
Anterior Chondro-sternal. 
Posterior Chondro-sternal. 
Capsular. 
Interarticular Chondro-sternal. 
Chondro-xiphoid. 
The Anterior Chondro-sternal or Sterno-costal Ligament (ligamentum sternocostale 
radiatum) (Fig. 212) is a broad and thin membranous band that radiates from 
the front of the inner extremity of the cartilages of the true ribs to the anterior 
surface of the sternum. It is composed of fasciculi which pass in different direc- 
tions. The superior fasciculi ascend obliquely, the inferior fasciculi pass obliquely 
downward, and the middle fasciculi pass horizontally. The superficial fibres of this 
ligament are the longest: they intermingle with the fibres of the ligaments above 
and below them, with those of the opposite side, and with the tendinous fibres of 
origin of the Pectoralis major, forming a thick fibrous membrane which covers 
the surface of the sternum (membrana sterni). This is more distinct at the lower 
than at the upper part. According to the modern nomenclature, this ligament 
and the posterior chondro-sternal ligament are called ligamenta sternoccstalia 
radiata. The two chondro-sternal ligaments form a sheath for the sternum 
anteriorly and posteriorly, the membrana sterni. 
The Posterior Chondro-sternal or Sterno-costal Ligament (ligamentum sterno- 
costale radiatum), less thick and distinct than the anterior, is composed of fibres 
which radiate from the posterior surface of the sternal end of the cartilages of 
the true ribs to the posterior surface of the sternum, becoming blended with the 
periosteum. 
The Capsular Ligament (capsula articularis) surrounds the joint formed between 
the cartilage of a true rib and the sternum. It is very thin, intimately blended 
with the anterior and posterior ligaments, and strengthened at the upper and lower 
part of the articulation by a few fibres which pass from the cartilage to the side 
of the sternum. These ligaments protect the synovial membranes. 
The Interarticular Chondro-sternal or Sterno-costal Ligament (ligamentum sterno- 
costale interarticulare) (Fig. 212).-This is found between the second costal car- 
tilage and the sternum. The cartilage of the second rib is connected with the 
sternum by means of an interarticular ligament attached by one extremity to the 
cartilage of the second rib, and by the other extremity to the cartilage which unites 
the first and second pieces of the sternum. This articulation is provided with two 
synovial membranes. The cartilage of the third rib is also connected with the ster- 
num by means of an interarticular ligament which is attached by one extremity to 
the cartilage of the third rib, and by the other extremity to the point of junction 
of the second and third pieces of the sternum. This articidation may be provided 
with two synovial membranes. In the other joints interarticular ligaments may 
exist, but they rarely completely divide the joint into two cavities. 
The Anterior Chondro-xiphoid or Costo-xiphoid Ligament (ligamentum costo- 
xiphoided) (Fig. 212).-This is a band of ligamentous fibres which connects 
the anterior surface of the seventh costal cartilage, and occasionally also that 
of the sixth, to the anterior surface of the ensiform appendix. It varies in 
length and breadth in different subjects. A similar band of fibres on the inter- 
nal or posterior surface, though less thick and distinct, may be demonstrated. 
It is spoken of as the posterior chondro-xiphoid or costo-xiphoid ligament. 
Synovial Membranes (Fig. 212).-There is no synovial membrane between the 
first costal cartilage and the sternum, as this cartilage is directly continuous with 
the sternum. There are two synovial membranes, both in the articulation of the 
second and third costal cartilages to the sternum. There is generally one syno- 
vial membrane in each of the joints between the fourth, fifth, sixth, and seventh ARTICULATION OF CARTILAGES OF RIBS WITH STERNUM 
289 
costal cartilages to the sternum; but it is sometimes absent in the sixth and 
seventh chondro-sternal joints. Thus there are usually eight synovial cavities on 
each side in the articulations between the costal cartilages of the true ribs and 
the sternum. After middle life the articular surfaces lose their polish, become 
I NTERARTICU LAR 
CHONDROSTERNAL 
LIGAMENT 
ANTERIOR CHONDRO- 
STERNAL LIGAMENT 
STERNOCOSTAL 
'ARTICULATION 
.1 NTERCHON DRAL 
ARTICULATION 
ANTERIOR CHONDRO- 
XIPHOID LIGAMENT 
Fig. 212.-Sternum and ribs with ligaments, from in front. In the left half of the figure the most anterior 
layer has been removed and the joint slits have been opened ; the parts are separated somewhat from one 
another on the left side. (Spalteholz.) 
roughened, and the synovial membranes appear to be wanting. In old age the 
articulations do not exist, the cartilages of most of the ribs becoming continuous 
with the sternum. 
Actions.-The movements which are permitted in the chondro-sternal articu- 
lations are limited to elevation and depression, and these only to a slight extent. 
Articulations of the Cartilages of the Ribs with Each Other or the Inter- 
chondral Articulations {articulationes inter chondr ales) (Fig. 212).-The con- 290 
THE ARTICULATIONS OU JOINTS 
tisuous borders of the sixth, seventh, and eighth, and sometimes the ninth and 
tenth, costal cartilages articulate with each other by small, smooth, oblong-shaped 
facets. Each articulation is enclosed in a thin capsular ligament lined by syno- 
vial membrane, and strengthened externally and internally by ligamentous fibres, 
external and internal interchondral ligaments (ligamenta intercostalia externa et 
interna), which pass from one cartilage to the other. Sometimes the fifth costal 
cartilage, more rarely that of the ninth, articulates, by its lower border, with the 
adjoining cartilage by a small oval facet; more frequently they are connected 
together by a few ligamentous fibres. Occasionally the articular surfaces above 
mentioned are wanting. 
Articulations of the Ribs with their Cartilages or the Costo-chondral 
Articulations (Fig. 212).-The outer extremity of each costal cartilage is re- 
ceived into a depression in the sternal ends of the ribs, and the two are held 
together by the periosteum. There is no real joint. Occasionally a synovial 
membrane exists between the first rib and the corresponding cartilage. 
VIII. Articulations of the Sternum (Fig. 212). 
The first piece of the sternum is united to the second either by an amphi- 
arthrodial joint-a single piece of true fibro-cartilage uniting the segments-or 
by a diarthrodial joint, in which each bone is clothed with a distinct lamina of 
cartilage, adherent on one side, free and lined with synovial membrane on the 
other. In the latter case the cartilage covering the gladiolus is continued without 
interruption on to the cartilages of the second ribs. Mr. Rivington has found the 
diarthrodial form of joint in about one-third of the specimens examined by him; 
Mr. Maisonneuve more frequently. It appears to be rare in childhood, and is 
formed, in Mr. Rivington's opinion, from the amphiarthrodial form by absorption. 
The diarthrodial joint seems to have no tendency to ossify at any age, while the 
amphiarthrodial is more liable to do so, and has been found ossified as early as 
thirty-four years of age. Professor Cunningham1 says: " It is not usual to find the 
manubri-gladiolar joint obliterated by the ossification of the two bony segments. 
Even in advanced life it remains open, and the joint partakes of the nature of 
an amphiarthrosis, although a joint cavity is not found under any circumstances 
in the plate of fibro-cartilage which intervenes between the manubrium and the 
gladiolus.'' The two segments are further connected by an 
Anterior Intersternal Ligament. Posterior Intersternal Ligament. 
The Anterior Intersternal Ligament consists of a layer of fibres, having a longi- 
tudinal direction; it blends with the fibres of the anterior chondro-sternal liga- 
ments on both sides (membrani sterni), and with the tendinous fibres of origin 
of the Pectoralis major muscle. This ligament is rough, irregular, and much 
thicker below than above. 
The Posterior Intersternal Ligament is disposed in a somewhat similar manner 
on the posterior surface of the articulation. 
IX. Articulation of the Vertebral Column with the Pelvis. 
The ligaments connecting the last lumbar vertebra with the sacrum are similar 
to those which connect the segments of the spine with each other-viz.: 1. The 
continuation downward of the anterior and posterior common ligaments. 2. The 
intervertebral substance connecting the flattened oval surfaces of the two bones 
1 Text-book of Anatomy, p. 264. ARTICULATION OF VERTEBRAL COLUMN WITH PELVIS 
291 
and forming an amphiarthrodial joint. 3. Ligamenta subflava, connecting the 
arch of the last lumbar vertebra with the posterior border of the sacral canal. 
4. Capsular ligaments connecting the articulating processes and forming a double 
arthrodia. 5. Inter- and supraspinous ligaments. 
The two proper ligaments connecting the pelvis with the spine are the lumbo- 
sacral and ilio-lumbar. 
The Lumbo-sacral Ligament (Fig. 213) is a short, thick, triangular fascic- 
ulus, which is connected above to the lower and front part of the trans- 
verse process of the last lumbar vertebra, passes obliquely outward, and is 
attached below to the lateral surface of the base of the sacrum. It is closely 
blended with the anterior sacro-iliac ligament and with the ilio-lumbar 
ligament, and is to be regarded as a portion of the ilio-lumbar ligament. 
This ligament is in relation, in front, with the Psoas muscle. The in- 
ternal border of the lumbo-sacral ligament margins the foramen of the last 
lumbar nerve. 
The Ilio-lumbar Ligament (ligamentum iliolumbale) (Fig. 213) passes horizon- 
tally outward from the apex of the transverse process of the last lumbar vertebra 
Aperture of communication 
with 
Bursa of psoas and iliacus 
Fig. 213.-Articulations of the pelvis and hip. Anterior view. 
Femur. 
to the crest of the ilium immediately in front of the sacro-iliac articulation. It 
is of a triangular form, thick and narrow internally, broad and thinner exter- 
nally. It is in relation, in front, with the Psoas muscle; behind, with the 
muscles occupying the vertebral groove; above, with the Quadratus lum- 
borum. It blends in places with the lumbo-sacral ligament, and its cres- 
centic inner margin marks the limit of the foramen for the fourth lumbar nerve. 
These ligaments are thick prolongations from the anterior layer of the lumbar 
fascia. 292 
THE ARTICULATIONS OR JOINTS 
X. Articulations of the Pelvis. 
The ligaments connecting the bones of the pelvis with each other may be 
divided into four groups: 1. Those connecting the sacrum and ilium. 2. Those 
passing between the sacrum and ischium. 3. Those connecting the sacrum and 
coccyx. 4. 'Those between the two pubic bones. 
1. Articulation of the Sacrum and Ilium (Articulatio Sacroiliaca.) 
The sacro-iliac articulation is an amphiarthrodial joint, formed between the 
lateral surfaces of the sacrum and ilium. The anterior or auricular portion of each 
articular surface is covered with a thin plate of cartilage, thicker on the sacrum 
than on the ilium, These are in close contact with each other, and to a certain 
extent united together by irregular patches of softer fibro-cartilage, and at their 
upper and posterior part by fine fibres of interosseous fibrous tissue. Throughout 
a considerable part of their extent, especially in advanced life, they are not 
connected together, but are separated by a space containing a synovial-like fluid, 
and hence the joint presents the characters of a diarthrosis. 
The ligaments connecting these surfaces are the 
Anterior Sacro-iliac. Posterior Sacro-iliac. 
Interosseous. 
The Anterior Sacro-iliac Ligaments (ligamenta sacroiliaca anteriora) (Fig. 213) 
consists of numerous thin bands which connect the anterior surfaces of the sacrum 
and ilium. 
The Posterior Sacro-iliac Ligament (ligamentum sacroiliacum posterius) (Fig. 214) 
is a strong interosseous ligament, situated in a deep depression between the sacrum 
and ilium behind, and forming the chief bond of connection between those bones. 
It consists of numerous strong fasciculi which pass between the bones in various 
directions. Three of these are of large size: the two superior fasciculi constitute 
the short sacro-iliac ligament (ligamentum sacroiliacum posterius breve). They are 
nearly horizontal in direction, arise from the first and second transverse tuber- 
cles on the posterior surface of the sacrum, and are inserted into the rough, 
uneven surface at the posterior part of the inner surface of the ilium, The 
third fasciculus, oblique in direction, is attached by one extremity to the third 
transverse tubercle on the posterior surface of the sacrum, and by the other to 
the posterior superior spine of the ilium; it is sometimes called the long or oblique 
sacro-iliac ligament (ligamentum sacroiliacum posterius longum). 
The Interosseous Ligaments (ligamenta sacroiliaca interossea) are completely 
covered by the posterior sacro-iliac ligament, and are not visible when the joint 
is unopened. The fibres are short and run obliquely and completely fill the 
hollow which exists posterior to the joint. 
The position of the sacro-iliac joint is indicated by the posterior superior spine of the ilium. 
This process is immediately behind the centre of the articulation. 
2. Ligaments passing between the Sacrum and Ischium (Fig. 214). 
The Great Sacro-sciatic (Posterior). 
The Lesser Sacro-sciatic (Anterior). 
The Great or Posterior Sacro-sciatic Ligament (ligamentum sacrotuberosum) (Figs. 
214 and 215) is situated at the lower and back part of the pelvis. It is flat, and 
triangular in form; narrower in the middle than at the extremities; attached by its 
broad base to the posterior inferior spine of the ilium, to the fourth and fifth trans- ARTICULATIONS OF THE PELVIS 
293 
verse tubercles of the sacrum, and to the lower part of the lateral margin of that bone 
and the coccyx. Passing obliquely downward, outward, and forward, it becomes 
narrow and thick, and at its insertion into the inner margin of the tuberosity of 
the ischium it increases in breadth, and is prolonged forward along the inner 
margin of the ramus, forming what is known as the falciform precess of the 
great sacro-sciatic ligament or the falciform ligament (processus falciformis). The 
free concave edge of this prolongation has attached to it the obturator fascia, 
with which it forms a kind of groove, protecting the internal pudic vessels and 
nerve. One of its surfaces is turned toward the perinaeum, the other toward 
the Obturator internus muscle. 
ANTERIOR Or LESSER 
SACRO-SCIATIC 
LIGAMENT. 
Femur.' 
Fig. 214.-Articulations of pelvis and hip. Posterior view. 
The posterior surface of this ligament gives origin, by its whole extent, to fibres 
of the Gluteus maximus muscle. Its anterior surface is united to the lesser sacro- 
sciatic ligament. Its external border forms, above, the posterior boundary of the 
great sacro-sciatic foramen, and, below, the posterior boundary of the lesser sacro- 
sciatic foramen. Its lower border forms part of the boundary of the perinaeum. It 
is pierced by the coccygeal branch of the sciatic artery and the coccygeal nerve. 
The Lesser or Anterior Sacro-sciatic Ligament (ligamentuni sacrospinosum) (Figs. 
214 and 215), much shorter and smaller than the preceding, is thin, triangular in 
form, attached by its apex to the spine of the ischium, and internally, by its broad 
base, to the lateral margin of the sacrum and coccyx, anterior to the attachment 
of the great sacro-sciatic ligament, with which its fibres are intermingled. 
It is in relation, anteriorly, with the Coccygeus muscle; posteriorly, it is covered 
by the great sacro-sciatic ligament and crossed by the internal pudic vessels and 
nerve. Its superior border forms the lower boundary of the great sacro-sciatic 
foramen; its inferior border, part of the lesser sacro-sciatic foramen. 294 
THE ARTICULATIONS OR JOINTS 
These two ligaments convert the sacro-sciatic notches into foramina. The 
superior or great sacro-sciatic foramen (foramen ischiadicum majus) (Figs. 214 and 
215) is bounded, in front and above, by the posterior border of the os innominatum; 
behind, by the great sacro-sciatic ligament; and below, by the lesser sacro-sciatic 
ligament. It is partially filled up, in the recent state, by the Pyriformis muscle, 
which passes through it. Above this muscle the gluteal vessels and superior gluteal 
nerve emerge from the pelvis, and, below it, the sciatic vessels and nerves, the inter- 
nal pudic vessels and nerve, the inferior gluteal nerve, and the nerves to the obtu- 
rator internus and quadratus femoris. The inferior or lesser sacro-sciatic foramen 
(foramen ischiadicum minus) (Figs. 214 and 215) is bounded, in front, by the 
ANT. SACRO-ILIAC 
LIGAM ENT. 
GREAT SACRO- 
SCIATIC LIGA- 
MENT. 
POUPART'S- 
LIGAM ENT. 
LESSER SACRO- 
SCIATIC LIGA- 
MENT. 
GREAT SACRO- 
SCIATIC LIGA- 
MENT. 
Obturator 
membrane. 
Fig. 215.-Side view of pelvis, showing the greater and lesser sacro-sciatic ligaments. 
tuber ischii; above, by the spine and lesser sacro-sciatic ligament; behind, by the 
greater sacro-sciatic ligament. It transmits the tendon of the Obturator internus 
muscle, its nerve, and the internal pudic vessels and nerve. 
3. Articulation of the Sacrum and Coccyx (Symphysis Sacrococcygea). 
This articulation is an amphiarthrodial joint, formed between the oval surface 
at the apex of the sacrum and the base of the coccyx. It is analogous to the 
joints between the bodies of the vertebrae. The ligaments are the 
Anterior Sacro-coccygeal. 
Posterior Sacro-coccygeal. 
Lateral Sacro-coccygeal. 
Interposed Fibro-cartilage 
The Anterior Sacro-coccygeal Ligament (lig amentum sacrococcygeum anterius) 
consists of a few irregular fibres which descend from the anterior surface of the 
sacrum to the front of the coccyx, becoming blended with the periosteum. It is 
a continuation of the anterior common ligament. 
The Posterior Sacro-coccygeal Ligament (ligamentum sacrococcygeum posterius) 
(Fig. 216) is divided into two portions, the deep and the superficial. The deep ARTICULATIONS OF THE PELVIS 
295 
portion of the posterior sacro-coccygeal ligament (ligamentum sacrococcygeum posterius 
projundum), which is a continuation of the posterior common ligament, is a flat 
band of a pearly tint, which arises from the margin of the lower orifice of the sacral 
canal, and descends to be inserted into the posterior surface of the coccyx. This 
ligament completes the lower and back part of the sacral canal. Its superficial 
fibres are much longer than the more deeply seated. This ligament is in rela- 
tion, behind, with the Gluteus maximus. 
The superficial portion of the posterior sacro-coccygeal ligament (ligamentum 
sacrococcygeum posterius superficiale} is composed of longitudinal fibrous bands 
which extend from the lower portion of the middle sacral ridge to the posterior 
surface of the coccyx and closes partly the hiatus sacralis; and of fibrous bands 
which extend from the sacral cornua to the coccygeal cornua. A portion of this 
ligament corresponds to the ligamenta subflava and the balance to the capsular 
ligament. 
A Lateral Sacro-coccygeal or Intertransverse Ligament (ligamentum sacrococcygeum 
laterale) (Fig. 216) connects the transverse process of the coccyx to the lower 
lateral angle of the sacrum on each side. 
APEX OF SACRUM 
LATERAL SACRO- 
COCCYGEAL LIGAMENT 
SUPERFICIAL PORTION OF POST 
SACRO-COCCYGEAL LIGAMENT 
DEEP PORTION OF POSTERIOR 
SACRO-COCCYGEAL LIGAMENT 
Fig. 216.-Ligaments between the sacrum and the coccyx. (Spalteholz.) 
A Fibro-cartilage is interposed between the contiguous surfaces of the sacrum 
and coccyx; it differs from that interposed between the bodies of the vertebrae in 
being thinner, and its central part firmer in texture. It is somewhat thicker in 
front and behind than at the sides. Occasionally, a synovial membrane is found 
and the coccyx is freely movable. This is especially the case during pregnancy. 
The different segments of the coccyx are connected together by an extension 
downward of the anterior and posterior sacro-coccygeal ligaments, a thin annular 
disk of fibro-cartilage being interposed between each of the bones. In the adult 
male all the pieces become ossified, but in the female this does not commonly 
occur until a later period of life. The separate segments of the coccyx are first 
united, and at a more advanced age the joint between the sacrum and coccyx is 
obliterated. 
Actions.-The movements which take place between the sacrum and coccyx, 
and between the different pieces of the latter bone, are forward and backu'ard, 
and are very limited. Their extent increases during pregnancy. 296 
THE ARTICULATIONS OR JOINTS 
4. Articulation of the Ossa Pubis (Symphysis Ossium Pubis) (Figs. 213,217). 
The articulation between the pubic bones is an amphiarthrodial joint, formed 
by the junction of the two oval articular surfaces of the ossa pubis. The liga- 
ments of this articulation are the 
Anterior Pubic. 
Posterior Pubic. 
Superior Pubic. 
Inferior Pubic. 
Interpubic Disk. 
The Anterior Pubic Ligament (ligamentum pubicum antenus) (Fig. 213) consists 
of several superimposed layers which pass across the front of the articulation. The 
superficial fibres pass obliquely from one bone to the other, decussating and form- 
ing an interlacement with the fibres of the aponeurosis of the External oblique and 
the tendon of the Rectus muscles. The deep fibres pass transversely across the 
symphysis, and are blended with the fibro-cartilage. 
The Posterior Pubic Ligament (ligamentum pubicum postering) consists of a 
few thin, scattered fibres which unite the two pubic bones posteriorly. 
The Superior Pubic Ligament (liga- 
mentum pubicum superius) (Fig. 213) 
is a band of fibres which connects to- 
gether the two pubic bones superiorly. 
The Inferior Pubic or Subpubic 
Ligament (ligamentum arcuatum 
pubis) (Fig. 213) is a thick, tri- 
angular arch of ligamentous fibres, 
connecting together the two pubic 
bones below and forming the upper 
boundary of the pubic arch. Above, 
it is blended with the interarticular 
fibro-cartilage; laterally it is united 
jvith the descending rami of the 
pubis. Its fibres are closely con- 
nected and have an arched direction. 
Its lower margin is separated from 
the triangular ligament of the per- 
inreum by a gap, through which runs 
the dorsal vein of the penis. 
The Interpubic Disk (lamina fibrocartilaginea interpubica) (Fig. 217) consists of a 
disk of cartilage and fibro-cartilage connecting the surfaces of the pubic bones in 
front. Each of the two surfaces is covered by a thin layer of hyaline cartilage which 
is firmly connected to the bone by a series of nipple-like processes which accu- 
rately fit within corresponding depressions on the osseous surfaces. These opposed 
cartilaginous surfaces are connected together by an intermediate stratum of fibrous 
tissue and fibro-cartilage which varies in thickness in different subjects. It often 
contains a cavity (cavum articulare) in its centre, probably formed by the soften- 
ing and absorption of the fibro-cartilage, since it rarely appears before the tenth 
year of life, and is not lined by synovial membrane. It is larger in the female 
than in the male, but it is very questionable whether it enlarges, as was formerly 
supposed, during pregnancy. It is most frequently limited to the upper and back 
part of the joint, but it occasionally reaches to the front, and may extend the 
entire length of the cartilage. This cavity may be easily demonstrated by making 
a vertical section of the symphysis pubis near its posterior surface (Fig. 217). 
The Obturator Ligament is more properly regarded as analogous to the muscular 
fasciae, with which it will be described. 
Hyaline cartilage covering bone. 
Intermediate fib ro-cart Hage. 
Cavity at upper 
and back part.v 
Fig. 217.-Vertical section of the symphysis pubis. 
Made near its posterior surface. STERNO-CLA VICULAR ARTICULA TION 
297 
ARTICULATIONS OF THE UPPER EXTREMITY. 
The articulations of the upper extremity may be arranged in the following 
groups: 
I. Sterno-clavicular Articulation. 
II. Acromio-clavicular Articulation. 
III. Ligaments of the Scapula. 
IV. Shoulder-joint. 
V. Elbow-joint. 
VI. Radio-ulnar Articulations. 
VII. Wrist-joint. 
VIII. Articulations of the Carpal Bones. 
IX. Carpo-metacarpal Articulations. 
X. Metacarpo-phalangeal Articula- 
tions. 
XI. Articulations of the Phalanges. 
I. Sterno-clavicular Articulation (Articulatio Sternoclavicularis) (Fig. 218). 
The sterno-clavicular is regarded by most anatomists as an arthrodial joint, 
but Cruveilhier considers it to be an articulation by reciprocal reception. Probably 
Fig. 218.-Sterno-clavicular articulation. Anterior view. 
the former opinion is the correct one, the varied movement which the joint enjoys 
being due to the interposition of an interarticular fibro-cartilage between the 
joint surfaces. The parts entering into its formation are the sternal end of the 
clavicle, the upper and lateral part of the first piece of the sternum, and the 
cartilage of the first rib. The articular surface of the sternum is covered with 
cartilage. The articular surface of the clavicle is much larger than that of the 
sternum, and invested with a layer of cartilage1 which is considerably thicker than 
that on the latter bone. The ligaments of this joint are the 
Capsular. 
Anterior Sterno-clavicular. 
Posterior Sterno-clavicular. 
Interclavicular. 
Costo-clavicular. 
Interarticular Fibro-cartilage. 
The Capsular Ligament (capsula articularis) completely surrounds the articula- 
tion, consisting of fibres of varying degrees of thickness and strength. Those in 
front and behind are of considerable thickness, and form the anterior and posterior 
sterno-clavicular ligaments; but those above and below, especially in the latter 
situation, are thin and scanty, and partake more of the character of connective 
tissue than true fibrous tissue. 
'According to Bruch, the sternal end of the clavicle is covered by a tissue which is rather fibrous than 
cartilaginous in structure. 298 
THE ARTICULATIONS OR JOINTS 
The Anterior Sterno-clavicular Ligament (ligamentum sternoclaviculare) (Fig. 218) 
is a part of the capsule. It is a broad band of fibres which covers the anterior sur- 
face of the articulation, being attached, above, to the upper and front part of the 
inner extremity of the clavicle, and, passing obliquely downward and inward, 
is attached, below, to the upper and front part of the first piece of the sternum. 
This ligament is covered, in front, by the sternal portion of the Sterno-cleido- 
mastoid and the integument; behind, it is in relation with the interarticular 
fibro-cartilage and the two synovial membranes. 
The Posterior Sterno-clavicular Ligament, also a part of the capsule, is a band of 
fibres which covers the posterior surface of the articulation, being attached, above, 
to the upper and back part of the inner extremity of the clavicle, and, passing 
obliquely downward and inward, is attached, below, to the upper and back part 
of the first piece of the sternum. It is in relation, in front, with the interartic- 
ular fibro-cartilage and synovial membranes; behind, with the Sterno-hyoid and 
Sterno-thyroid muscles. 
The Interclavicular Ligament (ligamentum interclaviculare} (Fig. 218) is a flat- 
tened band which varies considerably in form and size in different individuals; it 
passes in a curved direction from the upper part of the inner extremity of one 
clavicle to the other, and is also attached to the upper margin of the sternum. It 
is in relation, in front, with the integument; behind, with the Sterno-thyroid 
muscles. 
The Costo-clavicular or Rhomboid Ligament (ligamentum costoclaviculare) 
(Fig. 218) is short, flat, and strong; it is of a rhomboid form, attached, below, to 
'O' J J O' 7 7 7 
the upper and inner part of the cartilage of the first rib: it ascends obliquely back- 
ward and outward, and is attached, above, to the rhomboid depression on the 
under surface of the clavicle. It is in relation, in front, with the tendon of 
origin of the Subclavius; behind, with the subclavian vein. 
The Interarticular Fibro-cartilage (discus articularis) (Fig. 218) is a flat and nearly 
circular meniscus, interposed between the articulating surfaces of the sternum and 
clavicle. It is attached, above, to the upper and posterior border of the articular 
surface of the clavicle; below, to the cartilage of the first rib, at its junction with the 
sternum; and by its circumference, to the anterior and posterior sterno-clavicular 
and the interclavicular ligaments. It is thicker at the circumference, especially 
its upper and back part, than at its centre or below. It divides the joint into two 
cavities, each of which is furnished with a separate synovial membrane. 
Synovial Membrane.-Of the two synovial membranes found in this articulation, 
one is reflected from the sternal end of the clavicle over the adjacent surface of the 
fibro-cartilage and cartilage of the first rib; the other is placed between the articular 
surface of the sternum and adjacent surface of the fibro-cartilage; the latter is the 
larger of the two. 
Actions.-This articulation is the centre of the movements of the shoulder, and 
admits of a limited amount of motion in nearly every direction-upward, down- 
ward, backward, forward-as well as circumduction. When these movements take 
place in the joint, the clavicle in its motion carries the scapula with it, this bone 
gliding on the outer surface of the chest. This joint therefore forms the centre 
from which all movements of the supporting arch of the shoulder originate, and 
is the only point of articulation of this part of the skeleton with the trunk. "The 
movements attendant on elevation and depression of the shoulder take place 
between the clavicle and the interarticular fibro-cartilage, the bone rotating upon 
the ligament on an axis drawn from before backward through its own articular 
facet. When the shoulder is moved forward and backward, the clavicle, with 
the interarticular fibro-cartilage, rolls to and fro on the articular surface of the 
sternum, revolving, with a sliding movement, round an axis drawn nearly vertically 
through the sternum. In the circumduction of the shoulder, which is compounded A CR OMIO CL A VICULA R AR TICULA TION 
299 
of these two movements, the clavicle revolves upon the interarticular fibro-carti- 
lage, and the latter, with the clavicle, rolls upon the sternum."1 Elevation of the 
clavicle is principally limited by the costo-clavicular ligament; depression by the 
interclavicular. The muscles which raise the clavicle, as in shrugging the shoulder, 
are the upper fibres of the Trapezius, the Levator anguli scapulae, the clavicular 
head of the Sterno-mastoid, assisted to a certain extent by the two Rhomboids, 
which pull the vertebral border of the Scapula backward and upward, and so 
raise the clavicle. The depression of the clavicle is principally effected by gravity, 
assisted by the Subclavius, Pectoralis minor, and lower fibres of the Trapezius. 
It is drawn backward by the Rhomboids and the middle and lower fibres of the 
Trapezius; and forward by the Serratus magnus and Pectoralis minor. 
Surface Form.-The position of the stemo-clavicular joint may be easily ascertained by feel- 
ing the enlarged sternal end of the collar-bone just external to the long, cord-like, sternal origin 
of the Sterno-mastoid muscle. If this muscle is relaxed by bending the head forward, a depres- 
sion just internal to the end of the clavicle, and between it and the sternum, can be felt, indi- 
cating the exact position of the joint, which is subcutaneous. When the arm hangs by the side, 
the cavity of the joint is V-shaped. If the arm is raised, the bones become more closely approx- 
imated, and the cavity becomes a mere slit. 
Surgical Anatomy.-The strength of this joint mainly depends upon its ligaments, and 
it is because of the ligaments and because the force of a blow is generally transmitted along the 
long axis of the clavicle, that dislocation so rarely occurs, and that the bone is generally broken 
rather than displaced. When dislocation does occur, the course which the displaced bone takes 
depends more upon the direction in which the violence was applied than upon the anatomical 
construction of the joint; it may be either forward, backward, or upward. A complete upward 
dislocation is also inward. A complete forward or backward dislocation is also inward and 
downward. The chief point worthy of note, as regards the construction of the joint, in regard 
to dislocations, is the fact that, owing to the shape of the articular surfaces being so little 
adapted to each other, and that the strength of the joint mainly depends upon the ligaments, 
the displacement when reduced is very liable to recur, and hence it is extremely difficult to 
keep the end of the bone in its proper place, and it may be necessary to incise the soft parts 
and wire the bone in place. 
II. Acromio-clavicular Articulation or Scapulo-clavicular Articulation 
(Articulatio Acromioclavicularis) (Fig. 219). 
The acromio-clavicular is an arthrodial joint formed between the outer extrem- 
ity of the clavicle and the inner margin of the acromion process of the scapula. 
The ligaments which surround the joint form a capsule. The ligaments of this 
articulation are the 
Superior Acromio-clavicular. 
Inferior Acromio-clavicular. 
Interarticular Fibro-cartilage. 
Coraco-clavicular 
Trapezoid, 
and 
Conoid. 
The Superior Acromio-clavicular Ligament (ligamentum acromioclaviculare) (Figs. 
219 and 220) is a portion of the joint capsule. It is a quadrilateral band which 
covers the superior part of the articulation, extending between the upper part of 
the outer end of the clavicle and the adjoining part of the upper surface of the 
acromion. It is composed of parallel fibres which interlace with the aponeurosis 
of the Trapezius and Deltoid muscles; below, it is in contact with the inter- 
articular fibro-cartilage (when it exists) and the synovial membranes. 
The Inferior Acromio-clavicular Ligament, somewhat thinner than the pre- 
ceding, and like it a portion of the capsule, covers the under part of the articula- 
tion, and is attached to the adjoining surfaces of the two bones. It is in relation, 
above, with the synovial membranes, and in rare cases with the interarticular 
fibro-cartilage; below, with the tendon of the Supraspinatus. These two liga- 
1 Humphry. On the Human Skeleton, p. 402. 300 
THE ARTICULATIONS OR JOINTS 
ments are continuous with each other in front and behind, and form a complete 
capsule round the joint. 
The Interarticular Fibro-cartilage (discus articularis) is frequently absent in this 
articulation. When the meniscus exists it is generally incomplete and only par- 
tially separates the articular surfaces, and occupies the upper part of the articu- 
lation. More rarely it completely separates the joint into two cavities. 
SUPERIOR, 
TRANSVERSE 
LIGAMENT 
Fig. 219.-The left shoulder-joint, scapulo-clavicular articulations, and proper ligaments of scapula. 
The Synovial Membrane.-There is usually only one synovial membrane in 
this articulation, but when a complete interarticular fibro-cartilage exists there are 
two synovial membranes. 
The Coraco-clavicular Ligament (ligamentum coracoclaviculare) (Figs. 219 and 
220) serves to connect the clavicle with the coracoid process of the scapula. It does 
not properly belong to this articulation, but as it forms a most efficient means in 
retaining the clavicle in contact with the acromial process, it is usually described 
with it. It consists of two fasciculi, called the trapezoid and conoid ligaments. 
The trapezoid ligament (ligamentum trapezoideum), the anterior and external 
fasciculus, is broad, thin, and quadrilateral; it is placed obliquely between the 
coracoid process and the clavicle. It is attached, below, to the upper surface 
of the coracoid process; above, to the oblique line on the under surface of the 
clavicle. Its anterior border is free; its posterior border is joined with the conoid 
ligament, the two forming by their junction a projecting angle. 
The conoid ligament (ligamentum conoideum), the posterior and internal fas- 
ciculus, is a dense band of fibres, conical in form, the base being directed upward, 
the summit downward. It is attached by its apex to a rough impression at the 
base of the coracoid process, internal to the preceding; above, by its expanded PROPER LIGAMENTS OF THE SCAPULA 
301 
base, to the conoid tubercle on the under surface of the clavicle, and to a line 
proceeding internally from it for half an inch. These ligaments are in relation, 
in front, with the Subclavius and Deltoid; behind, with the Trapezius. They 
serve to limit rotation of the scapula, the Trapezoid limiting rotation forward, 
and the Conoid backward. 
Actions.-The movements of this articulation are of two kinds: 1. A gliding 
motion of the articular end of the clavicle on the acromion. 2. Rotation of the 
scapula forward and backward upon the clavicle, the extent of this rotation being 
limited by the two portions of the coraco-clavicular ligament. 
The acromio-clavicular joint has important functions in the movements of the 
upper extremity. It has been well pointed out by Sir George Humphry that if 
there had been no joint between the clavicle and scapula the circular movement of 
the scapula on the ribs (as in throwing both shoulders backward or forward) would 
have been attended with a greater alteration in the direction of the shoulder than is 
consistent with the free use of the arm in such position, and it would have been 
impossible to give a blow straight forward with the full force of the arm; that is to 
say, with the combined force of the scapula, arm, and forearm. "This joint," as 
he happily says*, "is so adjusted as to enable either bone to turn in a hinge-like 
manner upon a vertical axis drawn through the other, and it permits the surfaces 
of the scapula, like the baskets in a roundabout swing, to look the same way in 
every position or nearly so." Again, when the whole arch formed by the clavicle 
and scapula rises and falls (in elevation or depression of the shoulders), the joint 
between these two bones enables the scapula still to maintain its lower part in 
contact with the ribs. 
Surface Form.-The position of the acromio-clavicular joint can generally be ascertained by 
the slightly enlarged extremity of the outer end of the clavicle, which causes it to project above 
the level of the acromion process of the scapula. Sometimes this enlargement is so considerable 
as to form a rounded eminence, which is easily to be felt. The joint lies in the plane of a ver- 
tical line passing up the middle of the front of the arm. 
Surgical Anatomy.-Owing to the slanting shape of the articular surfaces of this joint, 
the commonest dislocation is the passing of the acromion process of the scapula under the 
outer end of the clavicle; but dislocations in the opposite direction have been described. The 
first form of dislocation is produced by violent force applied to the scapula, so as to drive the 
shoulder forward. The displacement in acromio-clavicular dislocation is often incomplete, on 
account of the strong coraco-clavicular ligaments which remain untorn. The same difficulty 
exists, as in the sterno-clavicular dislocation, in maintaining the ends of the bone in apposition after 
reduction, and it may become necessary to wire them in place after incision of the soft parts. 
III. Proper Ligaments of the Scapula (Figs. 219,220). 
The proper ligaments of the scapula pass between portions of that bone, but 
are not parts of an articulation. They are the 
Coraco-acromial. Superior Transverse. 
Inferior Transverse. 
The Coraco-acromial Ligament (lig amentum coracoacromiale) is a strong trian- 
gular band, extending between the coracoid and acromial processes. It is attached, 
by its apex, to the summit of the acromion just in front of the articular surface 
for the clavicle, and by its broad base to the whole length of the outer border of 
the coracoid process. Its posterior fibres are directed inward, its anterior fibres 
forward and inward. This ligament completes the vault formed by the coracoid and 
acromion processes for the protection of the head of the humerus. It is in relation, 
above, with the clavicle and under surface of the Deltoid muscle; below, with the 
tendon of the Supraspinatus muscle, a bursa being interposed. Its outer border is 
continuous with a dense lamina that passes beneath the Deltoid upon the tendons 302 
THE ARTICULATIONS OR JOINTS 
of the Supra- and Infraspinatus muscles. This ligament is sometimes described as 
consisting of two marginal bands and a thinner intervening portion, the two bands 
being attached respectively to the apex and base of the coracoid process, and join- 
ing together at their attachment into the acromion process. When the Pectoralis 
minor is inserted, as sometimes is the case, into the capsule of the shoulder-joint 
instead of into the coracoid process, it passes between these two bands, and the 
intervening portion is then deficient. 
The Superior Transverse, Coracoid or Suprascapular Ligament (lig amentum trans- 
versum scapula? superius) (Figs. 219, 220, and 222) converts the suprascapular 
SUPERIOR 
ACROMIOCLAVICULAR 
LIGAMENT 
SUPERIOR 
TRANSVERSE. 
/LIGAMENT 
GLENOID 
LIGAMENT 
Fig. 220.-Right clavicle and shoulder-blade with ligament, from without and somewhat from in front. 
(Spalteholz.) 
notch into a foramen. It is a thin and flat fasciculus, narrower at the middle 
than at the extremities, attached by one end to the base of the coracoid process, 
and by the other to the inner extremity of the scapular notch. The suprascapular 
nerve passes through the foramen; the suprascapular vessels pass over the liga- 
ment. 
An additional ligament, the Inferior Transverse or Spino-glenoid Ligament (liga- 
mentum transversum scapulae inferius), is sometimes found on the scapula, stretch- 
ing from the outer border of the spine to the margin of the glenoid cavity. When 
present, it forms an arch under which the suprascapular vessels and nerve pass as 
they enter the infraspinous fossa. 
Movements of Scapula.-The scapula is capable of being moved upward and 
downward, forward and backward, or, by a combination of these movements, cir- 
cumducted on the wall of the chest. The muscles which raise the scapula are the 
upper fibres of the Trapezius, the Levator anguli scapuhe, and the two Rhom- 
boids; those which depress it are the lower fibres of the Trapezius, the Pectoralis 
minor, and, through the clavicle, the Subclavius. The scapula is drawn backward 
by the Rhomboids and the middle and lower fibres of the Trapezius, and forward THE SHOULDER-JOINT 
303 
by the Serratus magnus and Pectoralis minor, assisted, when the arm is fixed, by 
the Pectoralis major. The mobility of the scapula is very considerable, and 
greatly assists the movements of the arm at the shoulder-joint. Thus, in raising 
the arm from the side the Deltoid and Supraspinatus can only lift it to a right 
CORACO-ACROMIAL 
LIGAMENT. 
BICEPS. 
GLENOID LIGAMENT. 
DELTOID. 
SU PR A-S PI N ATUS. 
DELTOID 
TERES MAJOR.' 
SU B- 
SCAPULA- 
RIS. 
TRICEPS. 
TRICEPS/ 
teres major. Circumflex vessels. 
Circumflex vessels 
SUB- 
SCAPULARIS. 
Fig. 221.-Vertical sections through the shoulder-joint, the arm being vertical and horizontal. (After Henle.) 
angle with the trunk, the further elevation of the limb being effected by the 
Trapezius and Serratus magnus moving the scapula on the wall of the chest. 
This mobility is of special importance in ankylosis of the shoulder-joint, the 
movement of this bone compensating to a very great extent for the immobility 
of the joint. 
IV. The Shoulder-joint (Articulatio Humeri) (Figs. 219, 220, 221, 222). 
The shoulder is an enarthrodial or ball-and-socket joint. The bones entering 
into its formation are the large globular head of the humerus, which is received 
into the shallow glenoid cavity of the scapula-an arrangement which permits of 
very considerable movement, whilst the joint itself is protected against displace- 
ment by the tendons which surround it and by atmospheric pressure. The liga- 
ments do not maintain the joint surfaces in apposition, because when they alone 
remain the humerus can be separated to a considerable extent from the glenoid 
cavity; their use, therefore, is to limit the amount of movement. Above, the joint 
is protected by an arched vault, formed by the under surfaces of the coracoid and 
acromion processes, and the coraco-acromial ligament. The articular surfaces 
are covered by a layer of cartilage: that on the head of the humerus is thicker at 
the centre than at the circumference, the reverse being the case in the glenoid 
cavity. The ligaments of the shoulder are the 
Capsular. 
Coraco-humeral. 
Transverse humeral 
Glenoid.1 
The Capsular Ligament (capsula articularis) (Figs. 219, 220, and 222) completely 
encircles the articulation, being attached, above, to the circumference of the glenoid 
cavity beyond the glenoid ligament, below, to the anatomical neck of the humerus, 
approaching nearer to the articular cartilage above than in the rest of its extent. 
It is thicker above and below than elsewhere, and is remarkably loose and lax, and 
1 The long tendon of origin of the Biceps muscle also acts as one of the ligaments of this joint. See the 
observations on p. 268 on the function of the muscles passing over more than one joint. 304 
THE ARTICULATIONS OR JOINTS 
much larger and longer than is necessary to keep the bones in contact, allowing 
them to be separated from each other more than an inch-an evident provision 
for that extreme freedom of movement which is peculiar to this articulation. Its 
superficial surface is strengthened, above, by the Supraspinatus; below, by the 
long head of the Triceps; behind, by the tendons of the Infraspinatus and Teres 
minor; and in front, by the tendon of the Subscapularis. The capsular ligament 
usually presents three openings: One anteriorly, below the coracoid process, 
establishes a communication between the synovial membrane of the joint and a. 
ARTICULAR 
CAPSULE 
LONG HEAD OF 
BICEPS MUSCLE 
SUPERIOR 
TRANSVERSE 
LIGAMENT 
SPINE OF SCAPULA 
(sawed otr at its origin) 
GLENO D 
LIGAMENT 
ARTICULAR 
CAPSULE 
Fig. 222.-Right shoulder-joint, frontal section, from behind. (Spalteholz.) 
bursa beneath the tendon of the Subscapularis muscle. The second, which is 
not constant, is at the posterior part, where a communication sometimes exists 
between the joint and a bursal sac belonging to the Infraspinatus muscle. The 
third is seen between the two tuberosities, for the passage of the long tendon 
of the Biceps muscle. It transmits a sac-like prolongation of the synovial 
membrane, which ends as a blind pouch opposite the surgical neck of the bone. 
This synovial sac is called the vagina mucosa intertubercularis. 
The Coraco-humeral Ligament (ligamentum coracohumerale) (Fig. 219) is a broad 
band which strengthens the upper part of the capsular ligament. It arises from 
the outer border of the coracoid process, and passes obliquely downward and out- 
ward to the front of the great tuberosity of the humerus, being blended with the 
tendon of the Supraspinatus muscle. This ligament is intimately united to the 
capsular ligament throughout the greater part of its extent. 
Supplemental Bands of the Capsular Ligament.-In addition to the coraco- 
humeral ligament, the capsular ligament is strengthened by supplemental bands in 
the interior of the joint. One of these bands is situated on the inner side of the 
joint, and passes from the inner edge of the glenoid cavity to the lower part of the 
lesser tuberosity of the humerus. This is sometimes known as Flood's ligament, THE SHOULDER- JOINT 
305 
and is supposed to correspond with the ligamentum teres of the hip-joint. A 
second of these bands is situated at the lower part of the joint, and passes from the 
under edge of the glenoid cavity to the under part of the neck of the humerus, and 
is known as Schlemm's ligament. A third, called the gleno-humeral ligament, is 
situated at the upper part of the joint, and projects into its interior, so that it can 
be seen only when the capsule is opened. It is attached above to the apex of the 
glenoid cavity, close to the root of the coracoid process, and, passing downward 
along the inner edge of the tendon of the Biceps, is attached below to the lesser 
tuberosity of the humerus, where it forms the inner boundary of the upper part of 
the bicipital groove. It is a thin, ribbon-like band, occasionally quite free from 
the capside. 
The Transverse Humeral Ligament is a prolongation of the capsular ligament. 
It is a broad band of fibrous tissue passing from the lesser to the greater tuber- 
osity of the humerus, and always limited to that portion of the bone which lies 
above the epiphysial line. It converts the bicipital groove into an osseo-aponeu- 
rotic canal, and is the analogue of the strong process of bone which connects the 
summits of the two tuberosities in the musk ox. 
The Glenoid Ligament (labrum glenoidale) (Figs. 220 and 222) is a fibro- 
cartilaginous rim, attached round the margin of the glenoid cavity. It is trian- 
gular on section, the thickest portion being fixed to the circumference of the cavity, 
the free edge being thin and sharp. It is continuous above with the long tendon 
of the Biceps muscle, which bifurcates at the upper part of the cavity into two 
fasciculi, and becomes continuous with the fibrous tissue of the glenoid ligament. 
This ligament deepens the cavity for articulation, and protects the edges of the 
bone. It is lined by the synovial membrane. 
Synovial Membrane (Fig. 222).-The synovial membrane is reflected from the 
margin of the glenoid cavity over the fibro-cartilaginous rim surrounding it: it is 
then reflected over the internal surface of the capsular ligament, covers the lower 
part and sides of the anatomical neck of the humerus as far as the cartilage cover- 
ing the head of the bone. The long tendon of the Biceps muscle which passes 
through the capsular ligament is enclosed in a tubular sheath of synovial membrane 
(vagina mucosa intertubercular is), which is reflected upon it at the point where it 
perforates the capsule, and is continued around it as far as the level of the surgical 
neck of the humerus. The tendon of the Biceps is thus enabled to traverse the 
articulation, but it is not contained in the interior of the synovial cavity. 
Bursse.-A large bursa exists between the joint capsule and the tendon of the 
Subscapularis muscle. It is called the subscapular bursa. This sac communicates 
with the shoulder-joint by means of an opening at the inner side of the capsular 
ligament. The subscapular bursa is constant. Occasionally another and smaller 
bursa exists beneath the tendon of the infraspinatus. It is called the infraspinatus 
bursa, and communicates with the shoulder-joint by means of an opening in the outer 
surface of the capsule. The subdeltoid or subacromial bursa is placed between the 
under surface of the Deltoid muscle and the outer surface of the capsule. It does 
not communicate with the joint. The subcutaneous acromial bursa is between the 
surface and the summit of the acromion process. There is a bursa beneath 
the Coraco-brachialis muscle-one beneath the teres major-and one beneath 
the tendinous portion of the latissimus dorsi. There is also a bursa between the 
tendon of insertion of the Pectoralis major muscle and the long head of the 
biceps. 
The Muscles in relation with the joint are, above, the Supraspinatus; below, the 
long head of the Triceps; in front, the Subscapularis; behind, the Infraspinatus 
and Teres minor; within, the long tendon of the Biceps. The Deltoid is placed 
most externally, and covers the articulation on its outer side, as well as in front 
and behind. 306 
THE ARTICULATIONS OR JOINTS 
The Arteries supplying the joint are articular branches of the anterior and 
posterior circumflex, and the suprascapular. 
The Nerves are derived from the circumflex and suprascapular. 
Actions.-The shoulder-joint is capable of movement in every direction, forward, 
backward, abduction, adduction, circumduction, and rotation. The humerus is 
drawn forward by the Pectoralis major, anterior fibres of the Deltoid, Coraco- 
brachialis, and by the Biceps when the forearm is flexed; backward, by the Latis- 
simus dorsi, Teres major, posterior fibres of the Deltoid, and by the Triceps when 
the forearm is extended; it is abducted (elevated) by the Deltoid and Supraspinatus; 
it is adducted (depressed) by the Subscapularis, Pectoralis major, Latissimus dorsi, 
and Teres major; it is rotated outward by the Infraspinatus and Teres minor; 
and it is rotated inward by the Subscapularis, Latissimus dorsi, Teres major, and 
Pectoralis major. 
The most striking peculiarities in this joint are: 1. The large size of the head 
of the humerus in comparison with the depth of the glenoid cavity, even when 
supplemented by the glenoid ligament. 2. The looseness of the capsule of the 
joint. 3. The intimate connection of the capsule with the muscles attached to the 
head of the humerus. 4. The peculiar relation of the biceps tendon to the joint. 
It is in consequence of the relative size of the two articular surfaces that the 
joint enjoys such free movement in every possible direction. When these move- 
ments of the arm are arrested in the shoulder-joint by the contact of the bony sur- 
faces and by the tension of the corresponding fibres of the capsule, together with 
that of the muscles acting as accessory ligaments, they can be carried considerably 
farther by the movements of the scapula, involving, of course, motion at the 
acromio- and sterno-clavicular joints. These joints are therefore to be regarded 
as accessory structures to the shoulder-joint.1 The extent of these movements of 
the scapula is very considerable, especially in extreme elevation of the arm, which 
movement is best accomplished when the arm is thrown somewhat forward and 
outward, because the margin of the head of the humerus is by no means a true 
circle; its greatest diameter is from the bicipital groove downward, inward, and 
backward, and the greatest elevation of the arm can be obtained by rolling its 
articular surface in the direction of the measurement. The great width of the 
central portion of the humeral head also allows of very free horizontal movement 
when the arm is raised to a right angle, in which movement the arch formed by the 
acromion, the coracoid process, and the coraco-acromial ligament constitutes a 
sort of supplemental articular cavity for the head of the bone. 
The looseness of the capsule is so great that the arm will fall about an inch 
from the scapula when the muscles are dissected from the capsular ligament and 
an opening made in it to remove the atmospheric pressure. The movements of 
the joint, therefore, are not regulated by the capsule so much as by the surrounding 
muscles and by the pressure of the atmosphere-an arrangement which "renders 
the movements of the joint much more easy than they would otherwise have been, 
and permits a swinging, pendulum-like vibration of the limb when the muscles 
are at rest" (Humphry). The fact, also, that in all ordinary positions of the joint 
the capsule is not put on the stretch enables the arm to move freely in all direc- 
tions. Extreme movements are checked by the tension of appropriate portions of 
the capsule, as well as by the interlocking of the bones. Thus it is said that 
" abduction is checked by the contact of the great tuberosity with the upper edge of 
the glenoid cavity, adduction by the tension of the coraco-humeral ligament" 
(Beaunis et Bouchard). Cleland2 maintains that the limitations of movement at 
the shoulder-joint are due to the structure of the joint itself, the glenoid ligament 
fitting, in different positions of the elevated arm, into the anatomical neck of the 
humerus. 
1 See p. 301. 2 Journal of Anatomy and Physiology, 1884, vol. xviii. THE SHOULDER- JOINT 
307 
Cathcart1 has pointed out that in abducting the arm and raising it above the 
head, the scapula rotates throughout the whole movement with the exception of 
a short space at the beginning and at the end; that the humerus moves on the 
scapula not only from the hanging to the horizontal position, but also in passing 
upward as it approaches the vertical above; that the clavicle moves not only 
during the second half of the movement but in the first as well, though to a less 
extent-i. e., the scapula and clavicle are concerned in the first stage as well as in 
the second; and that the humerus is partly involved in the second as well as 
chiefly in the first. 
The intimate union of the tendons of the four short muscles with the capsule 
converts these muscles into elastic and spontaneously acting ligaments of the joint, 
and it is regarded as being also intended to prevent the folds into which all portions 
of the capsule would alternately fall in the varying positions of the joint from being 
driven between the bones by the pressure of the atmosphere. 
The peculiar relations of the Biceps tendon to the shoulder-joint appear to sub- 
serve various purposes. In the first place, by its connection with both the shoulder 
and elbow the muscle harmonizes the action of the two joints, and acts as an 
elastic ligament in all positions, in the manner previously adverted to.2 Next, it 
strengthens the upper part of the articular cavity, and prevents the head of the 
humerus from being pressed up against the acromion process, when the Deltoid 
contracts, instead of forming the centre of motion in the glenoid cavity. By its 
passage along the bicipital groove it assists in rendering the head of the humerus 
steady in the various movements of the arm. When the arm is raised from the 
side it assists the Supra- and Infraspinatus in rotating the head of the humerus in 
the glenoid cavity. It also holds the head of the bone firmly in contact with the 
glenoid cavity, and prevents its slipping over its lower edge, or being displaced by 
the action of the Latissimus dorsi and Pectoralis major, as in climbing and many 
other movements. 
Surface Form.-The direction and position of the shoulder-joint may be indicated by a line 
drawn from the middle of the coraco-acromial ligament, in a curved direction, with its con- 
vexity inward, to the innermost part of that portion of the head of the humerus which can be 
felt in the axilla when the arm is forcibly abducted from the side. When the arm hangs by the 
side, not more than one-third of the head of the bone is in contact with the glenoid cavity, and 
three-quarters of its circumference is in front of a vertical line drawn from the anterior border 
of the acromion process. 
Surgical Anatomy.-Owing to the construction of the shoulder-joint and the freedom of 
movement which it enjoys, as well as in consequence of its exposed situation, it is more frequently 
dislocated than any other joint in the body. Dislocations of the shoulder contribute about forty 
per cent, of the cases in tables of dislocations. Dislocation occurs when the arm is thrown into 
extreme abduction, and when, therefore, the head of the humerus presses against the lower and 
front part of the capsule, which is the thinnest and least supported part of the ligament. The 
rent in the capsule almost invariably takes place in this situation, between the tendon of the Sub- 
scapularis and the Triceps, and through it the head of the bone escapes, so that the dislocation 
in most instances is primarily subglenoid. The head of the bone does not usually remain in this 
situation, but generally assumes some other position, which varies according to the direction and 
amount of force producing the dislocation and the relative strength of the muscles in front and 
behind the joint. In consequence of the muscles at the back being weaker than those in front, 
and especially on account of the long head of the Triceps preventing the bone passing backward, 
dislocation forward is much more common than backward. The most frequent position which 
the head of the humerus ultimately assumes is on the front of the neck of the scapula, beneath 
the coracoid process, and hence named subcoracoid dislocation. Occasionally, in consequence 
probably of a greater amount of force being brought to bear on the limb, the head is driven 
farther inward, and rests on the upper part of the front of the chest, beneath the clavicle (sub- 
clavicular). If the head of the bone passes under the Subscapularis muscle and also under 
the Teres major or the lower border of the Pectoralis major, the arm remains abducted, or even 
with the elbow raised above the head (luxatio erecta). Sometimes the humerus remains in the 
position in which it was primarily displaced, resting on the axillary border of the scapula (sub- 
1 Journal of Anatomy and Physiology, 1884, vol. xviii. 2 See p. 268 THE ARTICULATIONS OR JOINTS 
308 
glenoid), and rarely it passes backward and remains in the infraspinatous fossa beneath the 
spine (subspinous). If dislocation frequently recurs the condition may be amended in some 
cases by exposing the capsule and putting tucks in it by means of sutures. 
An old unreduced dislocation is sometimes treated by incising the soft parts and returning 
the head of the humerus into the glenoid cavity. In other cases the head of the humerus is 
excised. Dislocation of the long tendon of the Biceps muscle from the bicipital groove is a rare 
accident. When it occurs the arm is rigid in abduction, but the head of the humerus is found 
to be in the glenoid cavity. It is reduced by flexion of the elbow and rotation of the arm. 
Rupture of the long tendon of the biceps is more common than dislocation of the tendon. 
After this injury the belly of the muscle is relaxed and is nearer than normal to the elbow; 
flexion of the forearm is much weakened, and is weaker in supination than it is in pronation. 
The head of the humerus passes forward and inward, and the condition is often mistaken for 
dislocation of the bone. 
If we desire to aspirate the shoulder-joint, place the arm against the side, flex the forearm at 
a right angle to the arm, carry the forearm across the front of the chest, and enter the trocar 
below the acromion (De Vos). 
The shoulder-joint is sometimes the seat of all those inflammatory affections, both acute and 
chronic, which attack joints, though perhaps it suffers less frequently than some other joints of 
equal size and importance. Acute synovitis may result from injury, rheumatism, or pyaemia, or 
may follow secondarily on the so-called acute epiphysitis of infants. It is attended with effusion 
into the joint, and when this occurs the capsule is evenly distended and the contour of the joint 
rounded. Special projections may occur at the site of the openings in the capsular ligament. 
Thus a swelling may appear just in front of the joint, internal to the lesser tuberosity, from effu- 
sion into the bursa beneath the Subscapularis muscle; or, again, a swelling which is sometimes 
bilobed may be seen in the interval between the Deltoid and Pectoralis major muscles, from effu- 
sion into the diverticulum, which runs down the bicipital groove with the tendon of the biceps. 
The effusion into the synovial membrane can be best ascertained by examination from the axilla, 
where a soft, elastic, fluctuating swelling can usually be felt. The bursa beneath the deltoid is 
sometimes ruptured by violence, and sometimes inflames, suppurates, or becomes tuberculous. 
Tuberculous arthritis not unfrequently attacks the shoulder-joint, and may lead to total 
destruction of the articulation, when ankylosis may result or long-protracted suppuration may 
necessitate excision. This joint is also one of those which is most liable to be the seat of osteo- 
arthritis, and may also be affected in gout and rheumatism; or in locomotor ataxia, when it 
occasionally becomes the seat of Charcot's disease. 
Excision of the shoulder-joint may be required in cases of arthritis (especially the tuber- 
culous form) which have gone on to destruction of the articulation; in compound dislocations and 
fractures, particularly those arising from gunshot injuries, in which there has been extensive 
injury to the head of the bone; in some cases of old unreduced dislocation, where there is much 
pain; and possibly in some few cases of growth connected with the upper end of the bone. The 
operation is best performed by making an incision from the middle of the coraco-acromial liga- 
ment down the arm for about three inches: this will expose the bicipital groove and the tendon 
of the Biceps, which may be either divided or hooked out of the way, according as to whether it 
is implicated in the disease or not. The capsule is then freely opened, and the muscles attached 
to the greater and lesser tuberosities of the humerus divided. The head of the bone can then 
be thrust out of the wound and sawn off, or divided with a narrow saw in situ and subsequently 
removed. The section should be made, if possible, just below the articular surface, so as to 
leave the bone as long as possible. The glenoid cavity must then be examined, and gouged 
if carious. 
V. The Elbow-joint (Articulatio Cubiti) (Figs. 223, 224, 225, 226). 
The elbow is a ginglymus or hinge-joint. The bones entering into its forma- 
tion are the trochlea of the humerus, which is received into the greater sigmoid 
cavity of the ulna (articulatio humeroulnaris), and admits of the movements 
peculiar to this joint-viz., flexion and extension; whilst the capitellum or radial 
head of the humerus articulates with the cup-shaped depression on the head of 
the radius (articulatio humeroradialis); the circumference of the head of the 
radius articulates with the lesser sigmoid cavity of the ulna (articulatio radio- 
ulnaris proximalis), allowing of the movement of rotation of the radius on the 
ulna, the chief action of the superior radio-ulnar articulation. The articular 
surfaces are covered with a thin layer of cartilage, and connected together by a 
capsular ligament (capsula articuLaris) (Fig. 225) of unequal thickness, being 
especially thickened on its two sides and, to a less extent, in front and behind. THE ELBOW-JOINT 
309 
These thickened portions are usually described as distinct ligaments under the 
following names: 
Anterior. 
Posterior. 
Internal Lateral 
External Lateral. 
The orbicular ligament of the upper radio-ulnar articulation must also be 
reckoned among the ligaments of the elbow. 
The Anterior Ligament (Fig. 223) is a broad and thin fibrous layer which covers 
the anterior surface of the joint. It is attached to the front of the internal condyle 
and to the front of the humerus immediately above the coronoid and radial fossae; 
below, to the anterior surface of the coronoid process of the ulna and to the 
orbicular ligament, being continuous on each side with the lateral ligaments. Its 
Fig. 223.-Left elbow-joint, showing anterior 
and internal ligaments. 
Fig. 224.-Left elbow-joint, showing posterior 
and external ligaments. 
superficial fibres pass obliquely from the inner condyle of the humerus outward to 
the orbicular ligament. The middle fibres, vertical in direction, pass from the 
upper part of the coronoid depression and become partly blended with the pre- 
ceding, but are mainly inserted into the anterior surface of the coronoid process. 
The deep or transverse set intersects these at right angles. This ligament is in 
relation, in front, with the Brachialis anticus muscle, except at its outermost 
part; behind, it is in relation with the synovial membrane. 
The Posterior Ligament (Fig. 224) is a thin and loose membranous fold, attached, 
above, to the lower end of the humerus, above and at the sides of the olecranon 310 
THE ARTICULATIONS OR JOINTS 
fossa; below, to the groove on the upper and outer surfaces of the olecranon. The 
superficial or transverse fibres pass between the adjacent margins of the olecranon 
fossa. The deeper portion consists of vertical fibres, some of which, thin and 
weak, pass from the upper part of the olecranon fossa to the margin of the olec- 
ranon; others, thicker and stronger, pass from the back of the capitellum of the 
humerus to the posterior border of the lesser sigmoid cavity of the ulna. This 
ligament is in relation, behind, with the tendon of the Triceps muscle and the 
Anconeus muscle; in front, with the synovial membrane. 
The Internal Lateral Ligament (ligamentum coUaterale ulnare) (Fig. 223) is a 
thick triangular band consisting of two portions, an anterior and posterior, united 
by a thinner intermediate portion. The anterior portion, directed obliquely forward, 
is attached, above, by its apex, 
to the front part of the in- 
ternal condyle of the humerus; 
and, below, by its broad base, 
to the inner margin of the 
coronoid process. The poste- 
rior portion, also of triangular 
form, is attached, above, by 
its apex, to the lower and back 
part of the internal condyle; 
below, to the inner margin of 
the olecranon. Between these 
two bands a few intermediate 
fibres descend from the inter- 
nal condyle to blend with a 
transverse band of ligament- 
ous tissue which bridges 
across the notch between the 
olecranon and coronoid pro- 
cesses. This ligament is in 
relation, internally, with the 
Triceps and Flexor carpi 
ulnaris muscles and the ulnar 
nerve, and gives origin to part 
of the Flexor sublimis digi- 
torum muscle. 
The External Lateral Liga- 
ment (ligamentum coUaterale 
radiale) (Fig. 224) is a short 
and narrow fibrous band less 
distinct than the internal, at- 
tached, above, to a depression 
below the external condyle of 
the humerus; below, to the 
orbicular ligament, some of its 
most posterior fibres passing over that ligament, to be inserted into the outer 
margin of the ulna. This ligament is intimately blended with the tendon of 
origin of the Supinator brevis muscle. 
Synovial Membrane (Fig. 225).-The synovial membrane is very extensive. It 
covers the margin of the articular surface of the humerus, and lines the coronoid 
and olecranon fossa on that bone; from these points it is reflected over the anterior, 
posterior, and lateral ligaments, and forms a pouch (recessus sacciformis) between 
the lesser sigmoid cavity, the internal surface of the orbicular ligament, and the 
CORONOID 
PROCESS' 
OLECRANON 
' FOSSA 
ARTICULAR 
/CAPSULE 
EPIPHYSEAL 
junction' 
EPI PHYSEAL 
JUNCTION 
Fio. .225--Right elbow-joint, cut through at right angles to the 
axis of the trochlea humeri, from the ulnar side. (Spalteholz.) THE ELBOW-JOINT 
311 
circumference of the head of the radius. Projecting into the cavity is a crescentic 
fold of synovial membrane, between the radius and ulna, suggesting the division of 
the joint into two: one the humero-radial, the other the humero-ulnar. 
Between the capsular ligament and the synovial membrane are three masses 
of fat: one, the largest, above the olecranon fossa, which is pressed into the fossa by 
the Triceps during flexion; a second, over the coronoid fossa; and a third, over 
the radial fossa. Ihe two last-named pads are pressed into their respective fossae 
during extension. 
The muscles (Fig. 226) in relation with the joint are, in front, the Brachialis 
anticus; behind, the Triceps and Anconeus; externally, the Supinator brevis and 
the common tendon of origin of the Ex- 
tensor muscles ; internally, the common 
tendon of origin of the Flexor muscles, and 
the Flexor carpi ulnaris, with the ulnar 
nerve. 
The arteries supplying the joint are de- 
rived from the anastomosis between the 
superior profunda, inferior profunda, and 
anastomotica magna, branches of the 
brachial, with the anterior, posterior, and 
interosseous recurrent branches of the 
rdnar and the recurrent branch of the 
radial. These vessels form a complete 
chain of inosculation around the joint. 
The nerves are derived from the ulnar 
as it passes between the internal condyle 
and the olecranon ; a filament from the 
musculo-cutaneous (Riidinger), and two 
filaments from the median (Macalister). 
Bursae.-The olecranon bursa (bursa sub- 
cutaneous olecrani) is placed between the 
olecranon process and the cutaneous sur- 
face. A bursa exists between the tendon 
of the Biceps and the tubercle of the 
radius (bursa bicipitoradialis)-another 
between the Triceps tendon and the olec- 
ranon process (bursa subtendinea olecrani) 
-another between the cutaneous surface 
and the external condyle (bursa subcutanea epicondyli humeri lateralis)-another 
between the cutaneous surface and the internal condyle (bursa subcutanea 
epicondyli humeri medialis-another within the Triceps tendon at its insertion on 
the olecranon (bursa intratendinea olecrani). 
Actions.-The elbow-joint comprises three different portions-viz., the joint 
between the ulna and humerus, that between the head of the radius and the 
humerus, and the superior radio-ulnar articulation, described below. All these 
articular surfaces are invested by a common synovial membrane, and the move- 
ments of the whole joint should be studied together. The combination of the 
movements of flexion and extension of the forearm with those of pronation and 
supination of the hand, which is ensured by the two being performed at the 
same joint, is essential to the accuracy of the various minute movements of the 
hand. 
The portion of the joint between the ulna and humerus is a simple hinge- 
joint, and allows of movements of flexion and extension only. Owing to the 
obliquity of the trochlear surface of the humerus, this movement does not take 
Median 
cephalic 
vein. 
Head of 
radius. 
Radial 
nerve. 
Fig. 226.-Sagittal section of the right elbow- 
joint, taken somewhat obliquely and seen from the 
radial aspect. (After Braune.) THE ARTICULATIONS OR JOINTS 
312 
place in a straight line; so that when the forearm is extended and supinated 
the axis of the arm and forearm is not in the same line, but the one portion of the 
limb forms an angle with the others, and the hand, with the forearm, is directed 
outward. During flexion, on the other hand, the forearm and the hand tend to 
approach the middle line of the body, and thus enable the hand to be easily 
carried to the face. The shape of the articular surface of the humerus, with its 
prominences and depressions accurately adapted to the opposing surfaces of 
the olecranon, prevents any lateral movement. Flexion is produced by the 
action of the Biceps and Brachialis anticus, assisted by the muscles arising from 
the internal condyle of the humerus and the Supinator longus; extension, by the 
Triceps and Anconeus, assisted by the extensors of the wrist and by the Extensor 
communis digitorum and Extensor minimi digiti. 
The joint between the head of the radius and the capitellum or radial head of 
the humerus is an arthrodial joint. The bony surfaces would of themselves con- 
stitute an enarthrosis, and allow of movement in all directions were it not for the 
orbicular ligament by which the head of the radius is bound down firmly to the 
sigmoid cavity of the ulna, and which prevents any separation of the two bones 
laterally. It is to the same ligament that the head of the radius owes its security 
from dislocation, which would otherwise constantly occur as a consequence of the 
shallowness of the cup-like surface on the head of the radius. In fact, but for 
this ligament the tendon of the biceps would be liable to pull the head of the 
radius out of the joint.1 In complete extension the head of the radius glides so 
far back on the outer condyle that its edge is plainly felt at the back of the articu- 
lation. Flexion and extension of the elbow-joint are limited by the tension of 
the structures on the front and back of the joint, the limitation of flexion being 
also aided by the soft structures of the arm and forearm coming in contact. 
In combination with any position of flexion or extension the head of the radius 
can be rotated in the upper radio-ulnar joint, carrying the hand with it. The 
hand is directly articulated to the lower surface of the radius only, and the concave 
or sigmoid surface on the lower end of the radius travels round the lower end of 
the ulna. The latter bone is excluded from the wrist-joint (as will be seen in 
the sequel) by the interarticular fibro-cartilage. Thus, rotation of the head of the 
radius round an axis which passes through the centre of the radial head of the 
humerus imparts circular movement to the hand through a very considerable 
arc. 
Surface Form.-If the forearm be slightly flexed on the arm, a curved crease or fold with 
its convexity downward may be seen running across the front of the elbow, extending from one 
condyle to the other. The centre of this fold is some slight distance above the line of the joint. 
The position of the radio-humeral portion of the joint can be at once ascertained by feeling for a 
slight groove or depression between the head of the radius and the capitellum of the humerus at 
the back of the articulation. 
Surgical Anatomy.-From the great breadth of the joint, and the manner in which the 
articular surfaces are interlocked, and also on account of the strong lateral ligaments and 
the support which the joint derives from the mass of muscles attached to each condyle of the 
humerus, lateral displacement of the bones is very uncommon, whereas antero-posterior disloca- 
tion, on account of the shortness of the antero-posterior diameter, the weakness of the anterior 
and posterior ligaments, and the want of support of muscles, much more frequently takes place, 
dislocation backward taking place when the forearm is in a position of extension, and forward 
when in a position of flexion. For, in the former position, that of extension, the coronoid process 
is not interlocked into the coronoid fossa, and loses its grip to a certain extent, whereas the 
olecranon process is in the olecranon fossa, and entirely prevents displacement forward. On 
the other hand, during flexion, the coronoid process is in the coronoid fossa, and prevents dis- 
location backward, while the olecranon loses its grip and is not so efficient, as during extension, 
in preventing a forward displacement. When lateral dislocation does take place, it is generally 
incomplete. 
1 Humphry, op cit., p. 419. RADIO- ULNAR ARTICULATION 
313 
Dislocation of the elbow-joint is of common occurrence in children, far more common than 
dislocation of any other articulation, for, as a rule, fracture of a bone more frequently takes 
place, under the application of any severe violence, in young persons than dislocation. In 
lesions of this joint there is often very great difficulty in ascertaining the exact nature of the 
injury. Sprain of the elbow is a very common injury in childhood. Injury to the radio- 
humeral joint is frequently produced by lifting a child by the hand, as in swinging it over a 
gutter. The supinator brevis, which under normal circumstances would retain the head of the 
radius against the capitellum of the humerus, is unable to do so, the radio-humeral articulation 
receives the force and the orbicular ligament undergoes upward displacement, is caught 
between the head of the radius and the capitellum and jams the joint.1 This injury is often 
called subluxation of the head of the radius. 
The elbow-joint is occasionally the seat of acute synovitis. The synovial membrane then 
becomes distended with fluid, the bulging showing itself principally around the olecranon process; 
that is to say, on its inner and outer sides and above, in consequence of the laxness of the poste- 
rior ligament. Occasionally a well-marked, triangular projection may be seen on the outer 
side of the olecranon, from bulging of the synovial membrane beneath the Anconeus muscle. 
Again, there is often some swelling just above the head of the radius, in the line of the radio- 
humeral joint. There is generally not much swelling at the front of the joint, though sometimes 
deep-seated fulness beneath the Brachialis anticus may be noted. When suppuration occurs the 
abscess usually points at one or other border of the Triceps muscle; occasionally the pus dis- 
charges itself in front, near the insertion of the Brachialis anticus muscle. Chronic synovitis, 
usually of tuberculous origin, is of common occurrence in the elbow-joint: under these circum- 
stances the forearm tends to assume the position of semi-flexion, which is that of greatest ease 
and relaxation of ligaments. It should be borne in mind that should ankylosis occur in this or 
the extended position, the limb will not be nearly so useful as if it becomes ankylosed in a position 
of rather less than a right angle. Loose cartilages are sometimes met with in the elbow-joint, not 
so commonly, however, as in the knee; nor do they, as a rule, give rise to such urgent symptoms. 
They rarely require operative interference. The elbow-joint is also sometimes affected with 
osteo-arthritis, but this affection is less common in this articulation than in some other of the 
larger joints. Bursitis about the elbow is not uncommon. Enlargement of the subcutaneous 
bursa over the olecranon is known as miners' elbow. Enlargement of any one of the bursae 
may occur. 
Excision of the elbow is principally required for one of three conditions-viz., tuberculous 
arthritis, injury and its results, and ankylosis in a position which greatly impairs the useful- 
ness of the limb; but may be necessary for some other rarer conditions, such as disorganizing 
arthritis after pyaemia, unreduced dislocation, and osteo-arthritis. The results of the opera- 
tion are, as a rule, more favorable than those of excision of any other joint, and it is one, 
therefore, that the surgeon should never hesitate to perform, especially in the first three of 
the conditions mentioned above. The operation is best performed by a single vertical incision 
down the back of the joint, a transverse incision, over the outer condyle, being added if the 
parts are much thickened and fixed. A straight incision is made about four inches long, the 
mid-point of which is on a level with and a little to the inner side of the tip of the olecra- 
non. This incision is made down to the bone, through the substance of the Triceps muscle. 
The operator with the point of his knife, and guarding the soft parts with his thumb-nail, 
separates them from the bone. In doing this there are two structures which he should 
carefully avoid: the ulnar nerve, which lies parallel to his incision, but a little internal, as it 
courses dowm between the internal condyle and the olecranon process, and the prolongation of 
the Triceps into the deep fascia of the forearm over the Anconeus muscle. Having cleared the 
bones and divided the lateral and posterior ligaments, the forearm is strongly flexed and the 
ends of the bone turned out and sawn off. The section of the humerus should be through 
the base of the condyles, that of the ulna and radius should be just below the level of the lesser 
sigmoid cavity of the ulna and the neck of the radius. In this operation the object is to obtain 
such fibrous union as shall allow' free motion of the bones of the forearm; and, therefore, passive 
motion must be commenced early, that is to say, about the tenth day. 
VI. Radio-ulnar Articulation (Articulatio Radioulnaris). 
The articulation of the radius with the ulna is effected by ligaments which 
connect together both extremities as well as the shafts of these bones. It may, 
consequently, be subdivided into three articulations: (1) the superior radio-ulnar, 
which is a portion of the elbow-joint; (2) the middle radio-ulnar; and (3) the infe- 
rior radio-ulnar articulations. 
1 Mr. Jonathan Hutchinson. Jr., in Annals of Surgery, August, 1885. 314 
THE ARTICULATIONS OR JOINTS 
1. Superior or Proximal Radio-ulnar Articulation (Articulatio 
Radioulnaris Proximalis). 
This articulation is a trochoid or pivot-joint. The bones entering into its forma- 
tion are the inner side of the circumference of the head of the radius rotating within 
the lesser sigmoid cavity of the ulna. Its only ligament is the annular or orbicular. 
The Orbicular or Annular Ligament (ligamentum annulare radii) (Figs. 223, 224, 
and 227) is a strong, flat band of ligamentous fibres which surrounds the head of 
the radius and retains it in firm connection with the lesser sigmoid cavity of the 
ulna. It forms about four-fifths of an osseo-fibrous ring, attached by each end to 
the extremities of the lesser sigmoid cavity, and is smaller at the lower part of its 
circumference than above, by which means the head of the radius is more securely 
held in its position. Its outer surface is strengthened by the external lateral 
ligament of the elbow, and affords origin to part of the Supinator brevis muscle. 
Its inner surface is smooth, and lined by synovial membrane. The synovial 
membrane is continuous with that which lines the elbow-joint. 
Actions.-The movement which takes place in this articulation is limited to 
rotation of the head of the radius within the orbicular ligament, and upon the 
lesser sigmoid cavity of the ulna, rotation forward being called pronation; rotation 
backward, supination. Supination is performed by the Biceps and Supinator 
brevis, assisted to a slight extent by the Extensor muscles of the thumb and, 
in certain positions, by the Supinator longus. Pronation is performed by the 
Pronator radii teres and the Pronator quadratus, assisted, in some positions, by 
the Supinator longus. 
Surface Form.-The position of the superior radio-ulnar joint is marked on the surface of 
the body by the little dimple on the back of the elbow which indicates the position of the head 
of the radius. 
Surgical Anatomy.--Dislocation of the head of the radius alone is not an uncommon acci- 
dent, and occurs most frequently in young persons from falls on the hand when the forearm is 
extended and supinated, the head of the bone being displaced forward. It is attended by rup- 
ture of the orbicular ligament. Occasionally a peculiar injury, which is supposed to be a sub- 
luxation, occurs in young children in lifting them from the ground by the hand or forearm. It 
is believed that the head of the radius is displaced downward or the orbicular ligament upward, 
and the upper border of the ligament becomes folded over the head of the radius, between it and 
the capitellum of the humerus. 
2. Middle Radio-ulnar Ligaments. 
The interval between the shafts of the radius and ulna is occupied by two 
ligaments. 
Oblique. Interosseous. 
The Oblique or Round Ligament {chorda obligua) (Figs. 223 and 225) is a small, 
flattened fibrous band which extends obliquely downward and outward from the 
tubercle of the ulna at the base of the coronoid process to the radius a little below 
the bicipital tuberosity. Its fibres run in the opposite direction to those of the 
interosseous ligament, and it appears to be placed as a substitute for it in the 
upper part of the interosseous interval. This ligament is sometimes wanting. 
The Interosseous Membrane (membrana interossea antibrachii) (Fig. 227) is a 
broad and thin plane of fibrous tissue descending obliquely downward and inward, 
from the interosseous ridge on the radius to that on the ulna. It is deficient above, 
commencing about an inch beneath the tubercle of the radius; is broader in the 
middle than at either extremity; and presents an oval aperture just above its 
lower margin for the passage of the anterior interosseous vessels to the back of 
the forearm. This ligament serves to connect the bones and to increase the 
extent of surface for the attachment of the deep muscles. Between its upper RADIO- ULNAR ARTICULATION 
315 
border and the oblique ligament an interval exists through which the posterior 
interosseous vessels pass to the dorsum of the forearm. Two or three 
fibrous bands are occasionally found 
on the posterior surface of this mem- 
brane which descend obliquely from 
the ulna toward the radius, and which 
have consequently a direction contrary 
to that of the other fibres. It is in 
relation, in front, by its upper three- 
fourths with the Flexor longus pollicis 
on the outer side, and with the Flexor 
profundus digitorum on the inner, lying 
upon the interval between which are 
the anterior interosseous vessels and 
nerve ; by its lower fourth, with the 
Pronator quadratus; behind, with the 
Supinator brevis, Extensor ossis meta- 
carpi pollicis, Extensor brevis pollicis, 
Extensor longus pollicis, Extensor in- 
dicis; and, near the wrist, with the 
anterior interosseous artery and poste- 
rior interosseous nerve. 
ANNULAR LIGAMENT 
OF RADIUS 
TENDON OF 
BICEPS MUSCLE" 
(cut through) 
OBLIQUE 
LIGAMENT' 
3. Inferior or Distal Radio-ulnar 
Articulation (Articulatio Ra- 
DIOULNARIS DlSTALIs). 
INTEROSSEOUS 
MEMBRANE 
This is a pivot-joint, formed by the 
sigmoid cavity at the inner side of the 
lower end of the radius receiving the 
head of the ulna. The articular sur- 
faces are covered by a thin layer of 
cartilage, and connected together by a 
capsule (capsula articular is), portions 
of which are usually described as dis- 
tinct ligaments. The ligaments of the 
articulation are: 
Anterior Radio-ulnar. 
Posterior Radio-ulnar. 
Triangular Interarticular Fibro- 
cartilage. 
The Anterior Radio-ulnar Ligament 
(Fig. 228) is a narrow band of fibres 
extending from the anterior margin of 
the sigmoid cavity of the radius to the 
anterior surface of the head of the ulna. 
The Posterior Radio-ulnar Ligament 
(Fig. 229) extends between similar 
points on the posterior surface of the 
articulation. 
The Triangular Interarticular Fibro-cartilage {discus articular is} (Figs. 227 and 231) 
is triangular in shape, and is placed transversely beneath the head of the ulna, 
binding the lower end of this bone and the radius firmly together. Its periphery 
STYLOID 
.PROCESS 
OF ULNA 
TRIANGULAR 
I NTERARTICULAR 
Fl B ROC A RTI LAG E 
Fig. 227.-Bones of the right forearm, with ligaments 
from the volar surface. (Spalteholz.) 
STYLOID PROCESS 
OF RADIUS THE ARTICULATIONS OR JOINTS 
316 
is thicker than its centre, which is thin and occasionally perforated. It is attached 
by its apex to a depression which separates the styloid process of the ulna from 
the head of that bone; and by its base, which is thin, to the prominent edge of 
Inferior radio-ulnar 
articulation. 
Wrist-joint. 
\Carpal articulations. 
Carpo-metacarpal 
articulations. 
Fig. 228.-Ligaments of wrist and hand. Anterior view. 
the radius, which separates the sigmoid cavity from the carpal articulating sur- 
face. Its margins are united to the ligaments of the wrist-joint. Its upper sur- 
face, smooth and concave, articulates with the head of the ulna, forming an 
Inferior radio-ulnar 
articulation. 
Wrist-joint. 
Carpal articulations. 
Carpo-metacarpal 
articulations! 
Fig. 229.-Ligaments of wrist and hand. Posterior view. 
arthrodial joint; its under surface, also concave and smooth, forms part of the 
wrist-joint and articulates with the cuneiform and inner part of the semilunar 
bone. Both surfaces are lined by a synovial membrane-the upper surface, by RADIO - CARPAL OR WRIST-JOINT 
317 
one peculiar to the radio-ulnar articulation; the under surface, by the synovial 
membrane of the wrist. 
Synovial Membrane.-rl he synovial membrane (Fig. 231) of this articulation 
has been called, from its extreme looseness, the membrana sacciformis. It projects 
horizontally inward between the head of the ulna and the interarticular fibro- 
cartilage, and upward between the radius and the ulna, forming a very loose 
cul-de-sac (recessus saccijormis). The quantity 
of synovia which it contains is usually consider- 
able. The inferior radio-ulnar joint does not 
communicate with the wrist-joint. 
Actions.-The movement in the inferior radio- 
ulnar articulation is just the reverse of that in 
the superior radio-ulnar joint. It consists of a 
movement of rotation of the lower end of the 
radius round an axis which corresponds to the 
centre of the head of the ulna. When the radius 
rotates forward, pronation of the forearm and 
hand is the result; and when backward, supina- 
tion. It will thus be seen that in pronation and 
supination of the forearm and hand the radius 
describes a segment of a cone, the axis of which 
extends from the centre of the head of the radius 
to the middle of the head of the ulna. In this 
movement, however, the ulna is not quite sta- 
tionary, but rotates a little in the opposite direc- 
tion. So that it also describes the segment of a 
cone, though of smaller size than that described 
by the radius. The movement which causes this 
alteration in the position of the head of the ulna 
takes place principally at the shoulder-joint by a 
rotation of the humerus, but possibly also to a 
slight extent at the elbow-joint.1 
Surface Form.-The position of the inferior radio- 
ulnar joint may be ascertained by feeling for a slight 
groove at the back of the wrist, between the prominent 
head of the ulna and the lower end of the radius, when 
the forearm is in a state of almost complete pronation. 
VII. Radio-carpal or Wrist-joint (Articulatio 
Radiocarpea) (Figs. 228, 229, 231). 
The wrist is a condyloid articulation. The 
parts entering into its formation are the lower 
end of the radius and under surface of the 
interarticular fibro-cartilage, which form together 
the receiving cavity, and the scaphoid, semilunar, 
and the cuneiform bones, which form the condyle. The articular surface of the 
radius and the under surface of the interarticular fibro-cartilage are the receiving 
cavity, forming together a transversely elliptical concave surface. The articular 
surfaces of the scaphoid, semilunar, and cuneiform bones form together a smooth, 
convex surface, the condyle, which is received into the concavity above men- 
tioned. All the bony surfaces of the articulation are covered with cartilage, and 
Fig. 230.-Longitudinal section of the 
right forearm, hand, and third finger, 
viewed from the ulnar aspect. (After 
Braune.) 
1 See Journal of Anatomy and Physiology, vol. xix., parts ii., iii., and iv. 318 
THE ARTICULATIONS OR JOINTS 
connected together by a loose capsule (capsula articularis), which is divided into 
the following ligaments: 
External Lateral. 
Internal Lateral. 
Anterior. 
Posterior. 
The External Lateral Ligament (ligamentum collaterale carpi radiale) (Fig. 228) 
extends from the summit of the styloid process of the radius to the outer side of 
the scaphoid, some of its fibres being prolonged to the trapezium and annular 
ligament. 
The Internal Lateral Ligament (ligamentum collaterale carpi idnare) (Fig. 228) 
is a rounded cord, attached, above, to the extremity of the styloid process of the 
ulna, and dividing below into two fasciculi, which are attached, one to the inner 
side of the cuneiform bone, the other to the pisiform bone and annular ligament. 
The Anterior or Volar Ligament (ligamentum radiocarpeum volare) (Fig. 228) 
is a broad, membranous band, attached, above, to the anterior margin of the 
lower end of the radius, its styloid process, and the ulna: its fibres pass downward 
and inward to be inserted into the palmar surface of the scaphoid, semilunar, 
and cuneiform bones, some of the fibres being continued to the os magnum. In 
addition to this broad membrane there is a distinct rounded fasciculus, superficial 
to the rest, which passes from the base of the styloid process of the ulna to 
the semilunar and cuneiform bones. This ligament is perforated by numerous 
apertures for the passage of vessels, and is in relation, in front, with the tendons 
of the Flexor profundus digitorum and Flexor longus pollicis; behind, with the 
synovial membrane of the wrist-joint. 
The Posterior or Dorsal Ligament (ligamentum radiocarpeum dorsale) (Fig. 229), 
less thick and strong than the anterior, is attached, above, to the posterior border 
of the lower end of the radius; its fibres pass obliquely downward and inward, to 
be attached to the dorsal surface of the scaphoid, semilunar, and cuneiform bones, 
being continuous with those of the dorsal carpal ligaments. This ligament is in 
relation, behind, with the extensor tendons of the fingers; in jront, with the syno- 
vial membrane of the wrist. 
Synovial Membrane.-The synovial membrane (Fig. 231) lines the inner sur- 
face of the ligaments above described, extending from the lower end of the radius 
and interarticular fibro-cartilage above to the articular surfaces of the carpal bones 
below. It is loose and lax, and presents numerous folds, especially behind. 
Relations.-The wrist-joint is covered in front by the flexor and behind by the 
extensor tendons (Fig. 230); it is also in relation with the radial and ulnar 
arteries. 
The arteries supplying the joint are the anterior and posterior carpal branches 
of the radial and ulnar, the anterior and posterior interosseous, and some ascend- 
ing branches from the deep palmar arch. 
The nerves are derived from the ulnar and posterior interosseous. 
Actions.-The movements permitted in this joint are flexion, extension, abduc- 
tion, adduction, and circumduction. Its actions will be further studied with those 
of the carpus, with which they are combined. 
Surface Form.-The line of the radio-carpal joint is on a level with the apex of the styloid 
process of the ulna. 
Surgical Anatomy.-The wrist-joint is rarely dislocated, its strength depending mainly 
upon the numerous strong tendons which surround the articulation. Its security is further pro- 
vided for by the number of small bones of which the carpus is made up, and which are united 
by very strong ligaments. The slight movement which takes place between the several bones 
serves to break the jars that result from falls or blows on the hand. Dislocation backward, 
which is the more common dislocation, simulates to a considerable extent Colles's fracture of the 
radius, and is liable to be mistaken for it. The diagnosis can be easily made out by observing 
the relative position of the styloid processes of the radius and the ulna. In the natural condition ARTICULATIONS OF THE CARPUS 
319 
the styloid process of the radius is on a lower level-i. e., nearer the ground-when the arm hangs 
by the side, than that of the ulna, and the same would be the case in dislocation. In Colles's 
fracture, on the other hand, the styloid process of the radius is on the same or even a higher 
level than that of the ulna. 
The wrist-joint is occasionally the seat of acute synovitis, the result of traumatism or arising 
in the rheumatic or pysemic state. When the synovial sac is distended with fluid, the swelling 
is greatest on the dorsal aspect of the wrist, showing a general fulness, with some bulging between 
the tendons. The inflammation is prone to extend to the intercarpal joints and to attack also 
the sheaths of the tendons in the neighborhood. Chronic inflammation of the wrist is generally 
tuberculous, and often leads to similar disease in the synovial sheaths of adjacent tendons and of 
the intercarpal joints. The disease, therefore, when progressive, often leads to necrosis of the 
•carpal bones, and the result is often unsatisfactory. 
VIII. Articulations of the Carpus (Articulatio Intercarpea) 
(Figs. 228, 229, 231). 
These articulations may be subdivided into three sets: 
1. The Articulations of the First Row of Carpal Bones. 
2. The Articulations of the Second Row of Carpal Bones. 
3. The Articulations of the Two Rows with each other. 
1. Articulations of the First Row of Carpal Bones. 
These are arthrodial joints. The ligaments connecting the scaphoid, semi- 
lunar, and cuneiform bones are- 
Dorsal. Palmar. 
Two Interosseous 
The Dorsal Ligaments (ligamenta intercarpea dorsalia') are placed transversely 
behind the bones of the first row; they connect the scaphoid and semilunar and 
the semilunar and cuneiform. 
The Palmar or Volar Ligaments (ligamenta intercarpea volaria) connect the 
scaphoid and semilunar and the semilunar and cuneiform bones; they are less 
strong than the dorsal, and placed very deeply below the anterior ligament of 
the wrist. 
The Interosseous Ligaments (ligamenta intercarpea interossea) (Fig. 231) are two 
narrow bundles of fibrous tissue connecting the semilunar bone on one side with 
the scaphoid, and on the other with the cuneiform. They are on a level with 
the superior surfaces of these bones, and close the upper part of the spaces 
between them. Their upper surfaces are smooth, and form with the bones the 
convex articular surfaces of the wrist-joint. 
The ligaments connecting the pisiform bone are- 
Capsular. Two Palmar Ligaments. 
The Capsular Ligament (capsula articularis) is a thin membrane which con- 
nects the pisiform bone to the cuneiform. It is lined with a separate synovial 
membrane. 
The Two Palmar Ligaments are two strong fibrous bands which connect the 
pisiform to the unciform, the piso-uncinate ligament (ligamentum pisohamatum), 
and to the base of the fifth metacarpal bone, the piso-metacarpal ligament (liga- 
mentum pisometacarpeum). 
2. Articulations of the Second Row of Carpal Bones. 
These are also arthrodial joints. The articular surfaces are covered with 
cartilage, and connected by the following ligaments: 
Dorsal. Palmar. 
Three Interosseous. 320 
THE ARTICULATIONS OR JOINTS 
The Dorsal Ligaments Jigamenta intercarpea dorsalid) extend transversely from 
one bone to another on the dorsal surface, connecting the trapezium with the trape- 
zoid, the trapezoid with the os magnum, and the os magnum with the unciform. 
The Palmar or Volar Ligaments Jigamenta intercarpca volaria) have a similar 
arrangement on the palmar surface. 
The Three Interosseous Ligaments Jigamenta intercarpea intcrossea) (Fig. 231) 
much thicker than those of the first row, are placed one between the os magnum 
and the unciform, a second between the os magnum and the trapezoid, and a 
third between the trapezium and trapezoid. The first of these is much the 
strongest, and the third is sometimes wanting. 
3. Articulations of the Two Rows of Carpal Bones with Each Other 
(Figs. 228, 229, 231). 
The joint between the scaphoid, semilunar, and cuneiform, and the second row 
of the carpus, or the mid-carpal joint, is made up of three distinct portions; in the 
centre the head of the os magnum and the superior surface of the unciform 
articulate with the deep, cup-shaped cavity formed by the scaphoid and semi- 
lunar bones, and constitute a sort of ball-and-socket joint. On the outer side 
the trapezium and trapezoid articulate with the scaphoid, and on the inner side 
the unciform articulates with the cuneiform, forming gliding joints. 
The ligaments are: 
Anterior. 
Posterior. 
External Lateral. 
Internal Lateral. 
The Anterior, Palmar, or Volar Ligaments (Jigamenta intercarpea volaria} consist 
of short fibres, which pass, for the most part, from the palmar surface of the bones 
of the first row to the front of the os magnum. 
The Posterior or Dorsal Ligaments Jigamenta intercarpca dorsalid) consist of 
short, irregular bundles of fibres passing between the bones of the first and second 
row on the dorsal surface of the carpus. 
The Lateral Ligaments are very short: they are placed, one on the radial, the 
other on the ulnar side of the carpus; the former, the stronger and more distinct, 
connecting the scaphoid and trapezium bones, the latter the cuneiform and unci- 
form; they are continuous with the lateral ligaments of the wrist-joint. In addi- 
tion to these ligaments, a slender interosseous band sometimes connects the os 
magnum and the scaphoid. 
Synovial Membrane (Fig. 231).-The synovial membrane of the carpus is very 
extensive: it passes from the undersurface of the scaphoid, semilunar, and cunei- 
form bones to the upper surface of the bones of the second row, sending upward 
two prolongations-between the scaphoid and semilunar and the semilunar and 
cuneiform; sending downward three prolongations between the four bones of the 
second row, which are further continued onward into the carpo-metacarpal 
joints of the four inner metacarpal bones, and also for a short distance between 
the metacarpal bones. There is a separate synovial membrane between the 
pisiform and cuneiform bones. 
Actions.-The articulation of the hand and wrist, considered as a whole, is 
divided into three parts: (1) the radius and the interarticular fibro-cartilage; 
(2) the meniscus, formed by the scaphoid, semilunar, and cuneiform, the pisiform 
bone having no essential part in the movements of the hand; (3) the hand proper, 
the metacarpal bones with the four carpal bones on which they are supported-viz., 
the trapezium, trapezoid, os magnum, and unciform. These three elements form 
two joints: (1) the superior, wrist-joint proper, between the meniscus and bones 
of the forearm; (2) the inferior, between the hand and meniscus, transverse or 
mid-carpal joint. CARPO - META CARPAL ARTICULA TIONS 
321 
(1) The articulation between the forearm and carpus is a true condyloid artic- 
ulation, and therefore all movements but rotation are permitted. Flexion and 
extension are the most free, and of these a greater amount of extension than 
flexion is permitted on account of the articulating surfaces extending farther on 
the dorsal than on the palmar aspect of the carpal bones. In this movement the 
carpal bones rotate on a transverse axis drawn between the tips of the styloid 
processes of the radius and ulna. A certain amount of adduction (or ulnar 
flexion) and abduction (or radial flexion) is also permitted. Of these the former 
is considerably greater in extent than the latter. In this movement the carpus 
revolves upon an antero-posterior axis drawn through the centre of the wrist. 
Finally, circumduction is permitted by the consecutive movements of adduction, 
extension, abduction, and flexion, with intermediate movements between them. 
There is no rotation, but this is provided for by the supination and pronation 
of the radius on the ulna. The movement of flexion is performed by the Flexor 
carpi radialis, the Flexor carpi ulnaris, and the Palmaris longus; extension, 
by the Extensor carpi radialis longior et brevior and the Extensor carpi 
ulnaris; adduction (ulnar flexion), by the Flexor carpi ulnaris and the Ex- 
tensor carpi ulnaris ; and abduction (radial flexion), by the Extensors of the 
thumb and the Extensor carpi radialis longior et brevior and the Flexor carpi 
radialis. 
(2) The chief movements permitted in the transverse or mid-carpal joint are 
flexion and extension and a slight amount of rotation. In flexion and extension, 
which is the movement most freely enjoyed, the trapezium and trapezoid on the 
radial side and the unciform on the ulnar side glide forward and backward on the 
scaphoid and cuneiform respectively, while the head of the os magnum and the 
superior surface of the unciform rotate in the cup-shaped cavity of the scaphoid 
and semilunar. Flexion at this joint is freer than extension. A very trifling 
amount of rotation is also permitted, the head of the os magnum rotating round a 
vertical axis drawn through its own centre, while at the same time a slight gliding 
movement takes place in the lateral portions of the joint. 
IX. Carpo-metacarpal Articulations (Articulationes Carpometacarpeae) 
(Figs. 228, 229, 231). 
1. Articulation of the Metacarpal Bone of the Thumb with the 
Trapezium (Articulatio Carpometacarpea Pollicis). 
This is a joint of reciprocal reception, and enjoys great freedom of movement, 
on account of the configuration of its articular surfaces, which are saddle-shaped, 
so that, on section, each bone appears to be received into a cavity in the other, 
according to the direction in which they are cut. The joint is surrounded by a 
capsular ligament. 
The Capsular Ligament (capsula articidaris) is thick and fibrous, but loose, 
and passes from the circumference of the upper extremity of the meta- 
carpal bone to the rough edge bounding the articular surface of the trape- 
zium; it is thickest externally and behind, and lined by a separate synovial 
membrane. 
Movements.-In the articulation of the metacarpal bone of the thumb with the 
trapezium the movements permitted are flexion, extension, adduction, abduction, 
and circumduction. When the joint is flexed the metacarpal bone is brought in 
front of the palm and the thumb is gradually turned to the fingers. It is by this 
peculiar movement that the tip of the thumb is opposed to the other digits; for 
by slightly flexing the fingers the palmar surface of the thumb can be brought in 
contact with their palmar surfaces one after another. THE ARTICULATIONS OR JOINTS 
322 
2. Articulations of the Metacarpal Bones of the Four Inner Fingers 
with the Carpus (Articulationes Carpometacarpea). 
The joints formed between the carpus and four inner metacarpal bones are 
arthrodial joints. The ligaments are- 
Dorsal. Palmar. 
Interosseous. 
The Dorsal Ligaments {ligamenta carpometacarpea dorsalia), the strongest and 
most distinct, connect the carpal and metacarpal bones on their dorsal surface. 
EPIPHYSEAL 
JUNCTION 
MEMBRANA SACCI- 
FORM IS OF INFERIOR 
RADIO-ULNAR 
ARTICULATION 
EPIPHYSEAL 
JUNCTION 
TRIANGULAR 
Fl BRO-CARTI LAGE . 
RADIO-CARPAL 
"ARTICULATION 
STYLOID PROCESS 
OF ULNA 
INTERCARPAL 
"ARTICULATION 
INTEROSSEOUS 
LIGAMENT 
ARTICULATION OF 
TRAPEZIUM AND 
METACARPAL BONE 
"OF THUMB 
INTEROSSEOUS 
LIGAMENT 
•CARPO-METACAR PAL 
ARTICULATION 
INTERMETACARPAL 
ARTICULATION' 
METACARPAL BONES 
Fig. 231.-Joints of the right hand, from the back of the hand. (Spalteholz.) 
The second metacarpal bone receives two fasciculi-one from the trapezium, 
the other from the trapezoid; the third metacarpal receives two-one from 
the trapezoid and one from the os magnum; the fourth two-one from the os 
magnum and one from the unciform; the fifth receives a single fasciculus from 
the unciform bone, which is continuous with a similar ligament on the palmar 
surface, forming an incomplete capsule. 
The Palmar or Volar Ligaments (ligamenta carpometacarpea volaria) have a 
somewhat similar arrangement on the palmar surface, with the exception of 
the third metacarpal, which has three ligaments-an external one from the CARPO - META CARPAL ARTICULA TIONS 
323 
trapezium, situated above the sheath of the tendon of the Flexor carpi radialis; 
a middle one, from the os magnum; and an internal one, from the unciform. 
The Interosseous Ligaments consist of short, thick fibres, which are limited to 
one part of the carpo-metacarpal articulation; they connect the contiguous inferior 
angles of the os magnum and unciform with the adjacent surfaces of the third 
and fourth metacarpal bones. 
Synovial Membrane.-The synovial membrane is a continuation of that between 
the two rows of carpal bones. Occasionally, the articulation of the unciform 
with the fourth and fifth metacarpal bones has a separate synovial membrane. 
The synovial membranes of the wrist and carpus (Fig. 231) are thus seen to 
be five in number. The first, the membrana sacciformis or the recessus sacciformis 
of the inferior radio-ulnar articulation, passes from the lower end of the ulna to 
TENDON OF FLEXOR 
SUBLIMIS DIGITORUM 
TENDON OF FLEXOR 
PROFUNDUS DIGITORUM 
LATERAL 
LIGAMENT 
ANTERIOR 
OR VAGINAL' 
LIGAMENT 
TRANSVERSE/ 
METACARPAL 
LIGAMENT 
SECOND LUM- 
BRICAL MUSCLE 
TRANSVERSE META- 
CARPAL LIGAMENT 
ANTERIOR OR 
VAGINAL LIGAMENT 
ANTERIOR OR 
VAGINAL LIGAMENT 
SECOND 
PALMAR 
I NTEROSSEOUS 
MUSCLE 
Fig. 232.-Metacarpal bones and first phalanges of the second to the fifth finger of the right hand, with 
ligaments, from the volar surface. (Spalteholz.) 
the sigmoid cavity of the radius, and lines the upper surface of the interarticular 
fibro-cartilage. The second passes from the lower end of the radius and inter- 
articular fibro-cartilage above to the bones of the first row below, The third, 
the most extensive, passes between the contiguous margins of the two rows of 
carpal bones-between the bones of the second row to the carpal extremities of 
the four inner metacarpal bones. The fourth, from the margin of the trapezium 
to the metacarpal bone of the thumb. The fifth, between the adjacent margins 
of the cuneiform and pisiform bones. 
Actions.-The movement permitted in the carpo-metacarpal articulations of the 
four inner fingers is limited to a slight gliding of the articular surfaces upon each 
other, the extent of which varies in the different joints. Thus the articulation of the 
metacarpal bone of the little finger is most movable, then that of the ring finger. 
The metacarpal bones of the index and middle fingers are almost immovable. 324 
THE ARTICULATIONS OR JOINTS 
3. Articulations of the Metacarpal Bones with Each Other (Articu- 
lationes Intermetacarpe.e (Figs. 228, 229, 231). 
The carpal extremities of the four inner metacarpal bones articulate with 
one another at each side by small surfaces covered with cartilages, and connected 
together by dorsal, palmar, and interosseous ligaments. 
The Dorsal Ligaments (ligamenta basium oss. metacarp, dorsalid) and Palmar 
Ligaments {ligamenta basium oss. metacarp, volarid) pass transversely from one 
bone to another on the dorsal and palmar sur- 
faces. 
The Interosseous Ligaments (ligamenta basium 
oss. metacarp, interossed) pass between their con- 
tiguous surfaces, just beneath their lateral artic- 
ular facets. 
Synovial Membrane (Fig. 231).-The synovial 
membrane between the lateral facets is a reflec- 
tion from that between the two rows of carpal 
bones. 
The Transverse Metacarpal Ligament (liga- 
mentum capitulorum oss. metacarpalium trans- 
versum) (Fig. 232) is a narrow, fibrous band 
which passes transversely across the anterior sur- 
faces of the digital extremities of the four inner 
metacarpal bones, connecting them together. It 
is blended anteriorly with the palmar ligaments 
of the metacarpo-phalangeal articulations. To 
its posterior border is connected the fascia which 
covers the Interossei muscles. Its anterior sur- 
face is concave where the flexor tendons pass 
over it. Behind it the tendons of the Interossei 
muscles pass to their insertion. 
X. Metacarpo-phalangeal Articulations (Artic- 
ulationes Metacarpo-phalangeae) 
(Figs. 232, 233). 
These articulations are of the condyloid kind, 
formed by the reception of the rounded head of 
the metacarpal bone into a shallow cavity in the 
extremity of the first phalanx. The expansion 
of the extensor tendon acts as a dorsal ligament. 
There is a capsular ligament which at certain 
points has strengthening ligaments. The liga- 
ments are- 
Anterior. Two Lateral. 
The Anterior, Palmar, or Vaginal Ligament 
(glenoid ligament of Cruveilhier, ligamentum 
vaginate) is a thick, dense, fibrous structure, 
placed on the palmar surface of the joint in the 
interval between the lateral ligaments, to which 
it is connected; it is loosely united to the meta- 
carpal bone, but very firmly to the base of the first phalanx. Its palmar surface 
is intimately blended with the transverse metacarpal ligament, and presents a 
ARTICULAR 
CAPSULE 
LATERAL 
"LIGAMENT 
LATERAL 
'LIGAMENT 
ARTICULAR. 
CAPSULE 
ARTICULAR 
CAPSULE 
LATERAL 
LIGAMEN 
Fig. 233. - Metacarpal bones and first 
phalanges of the third finger of the right 
hand, with ligaments, from the radial side. 
(Spalteholz.) THE HIP-JOINT 
325 
groove for the passage of the flexor tendons, the sheath surrounding which is 
connected to each side of the groove. By its deep surface it forms part of the 
articular surface for the head of the metacarpal bone, and is lined by a synovial 
membrane. 
The Lateral or Collateral Ligaments (ligamenta collateralia) are strong, rounded 
cords placed one on each side of the joint, each being attached by one extremity 
to the posterior tubercle on the side of the head of the metacarpal bone, and by 
the other to the contiguous extremity of the phalanx. 
Actions.-The movements which occur in these joints are flexion, extension, 
adduction, abduction, and circumduction; the lateral movements are very limited. 
Surface Form.-The prominences of the knuckles do not correspond to the position of the 
joints either of the metacarpo-phalangeal or interphalangeal articulations. These prominences 
are invariably formed by the distal ends of the proximal bone of each joint, and the line indi- 
cating the position of the joint must be sought considerably in front of the middle of the knuckle. 
The usual rule for finding these joints is to flex the distal phalanx on the proximal one to a right 
angle; the position of the joint is then indicated by an imaginary line drawn along the middle of 
the lateral aspect of the proximal phalanx. 
XI. Articulations of the Phalanges (Articulationes Digitorum Manus) 
(Fig. 233). 
These are ginglymus joints. Each joint has a capsule, and certain accentuated 
portions are regarded as definite ligaments. These ligaments are- 
Anterior or Palmar. Two Lateral (fligamenta collateralia). 
The arrangement of these ligaments is similar to those in the metacarpo- 
phalangeal articulations; the extensor tendon supplies the place of a dorsal 
ligament. 
Actions.-The only movements permitted in the phalangeal joints are -flexion 
and extension; these movements are more extensive between the first and second 
phalanges than between the second and third. The movement of flexion is very 
considerable, but extension is limited by the anterior and lateral ligaments. 
ARTICULATIONS OF THE LOWER EXTREMITY. 
The articulations of the Lower Extremity comprise the following groups: 
I. The Hip-joint. 
II. The Knee-joint. 
III. The Articulations between the 
Tibia and Fibula. 
IV. The Ankle-joint. 
V. The Articulations of the Tarsus. 
VI. TheTarso-metatarsal Articulations. 
VII. Articulations of the Metatarsal 
Bones with each other. 
VIII. The Metatarso-phalangeal Artic- 
ulations. 
IX. The Articulations of the Phalanges. 
I. The Hip-joint (Articulatio Coxae' (Figs. 234, 235, 236, 237, 238, 239). 
This articulation is an enarthrodial or ball-and-socket joint, formed by the 
reception of the head of the femur into the cup-shaped cavity of the acetabulum. 
The articulating surfaces are covered with cartilage, that on the head of the femur 
being thicker at the centre than at the circumference, and covering the entire 
surface, with the exception of a depression just below its centre for the ligamen- 
tum teres; that covering the acetabulum is much thinner at the centre than at 
the circumference. It forms an incomplete cartilaginous ring of a horseshoe 
shape, being deficient below, where there is a circular depression, which is occu- 326 
THE ARTICULATIONS OR JOINTS 
pied in the recent state by a mass of fat covered by synovial membrane. The 
ligaments of the joints are the 
Capsular. Teres. 
Ilio-femoral. Cotyloid. 
Transverse. 
The Capsular Ligament (capsula art ic ular is} (Figs. 234, 235, 237, and 239) is a 
strong, dense, ligamentous capsule, embracing the margin of the acetabulum 
above and surrounding the neck of the femur below. Its upper circumference 
ANTERIOR INFERIOR 
SPINE OF ILIUM 
ANTERIOR 
INTERTRO-, 
CHANTERIC LINE 
<LESSER 
TROCHANTER 
Fig. 234.-Right hip-joint, from in front. (Spalteholz.) 
is attached to the acetabulum, above and behind, two or three lines external 
to the cotyloid ligament; but in front it is attached to the outer margin of 
this ligament, and opposite to the notch, where the margin of this cavity is 
deficient, it is connected to the transverse ligament, and by a few fibres to 
the edge of the obturator foramen. Its lower circumference surrounds the neck 
of the femur, being attached, in front, to the spiral or anterior intertrochanteric 
line; above, to the base of the neck; behind, to the neck of the bone, about half THE HIP-JOINT 
327 
an inch above the posterior intertrochanteric line. From this insertion the fibres 
are reflected upward over the neck of the femur, forming a sort of tubular sheath, 
the cervical reflection, which blends with the periosteum and can be traced as far 
as the articular cartilage. On the surface of the neck of the femur some of these 
reflected fibres are raised into longitudinal folds, termed retinacula. It is much 
thicker at the upper and forepart of the joint, where the greatest amount of 
POSTERIOR INTER- 
TROCHANTERIC LINE 
LESSER 
trochanter' 
Fig. 235.-Right hip-joint, from behind. (The joint capsule, except for the strengthening ligaments, has 
been removed.) (Spalteholz.) 
resistance is required, than below and internally, where it is thin, loose, and 
longer than in any other part. It consists of two sets of fibres, circular and lon- 
gitudinal. The circular fibres, zona orbicularis (Fig. 237), are most abundant at the 
lower and back part of the capsule, and form a sling or collar around the neck of 
the femur. Anteriorly they blend with the deep surface of the ilio-femoral liga- 
ment, and through its medium reach the anterior inferior spine of the ilium. The 
longitudinal fibres are greatest in amount at the upper and front part of the cap- 
sule, where they form distinct bands or accessory ligaments, of which the most 
important is the ilio-femoral. Other accessory bands are known as the pubo- 328 
THE ARTICULATIONS OR JOINTS 
femoral or pubo-capsular ligament (ligamentum pubocapsidare), passing from the 
outer portion of the horizontal pubic ramus, the ilio-pectineal eminence, the 
obturator crest and the obturator membrane, to the front of the capsule; and 
ischio-capsular ligament or ligament of Bertin (ligamenturn ischiocapsulare), 
passing from the ischium, just below the acetabulum, to blend with the circular 
fibres at the lower part of the joint. The external surface is rough, covered by 
numerous muscles, and separated in front from the Psoas and Iliacus muscles by 
a synovial bursa, which not infrequently communicates, by a circular aperture, 
with the cavity of the joint. It differs from the capsular ligament of the shoulder 
in being much less loose and lax, and in not being perforated for the passage of 
a tendon. 
ANTERIOR 
IN FERIOR. 
SPINE OF ILIUM 
SPINE OF 
ISCHIUM 
TRANSVERSE 
LIGAMENT OF- 
ACETABULUM 
TUBEROSITY 
"of ischium 
Fig. 236.-Right hip-joint from the medial side. (The bottom of the acetabulum has been chiselled away 
sufficiently to make the head of the femur visible.) (Spalteholz.) 
The Ilio-femoral or Y-ligament or Ligament of Bigelow (ligamentum ilio- 
femorale) (Figs. 234, 235, 237, and 238) is an accessory band of fibres extending 
obliquely across the front of the joint; it is intimately connected with the cap- 
sular ligament, and serves to strengthen it in this situation. It is attached, 
above, to the lower part of the anterior inferior spine of the ilium and the 
adjacent rim of the acetabulum; and, diverging below, forms two bands, of 
which one passes downward to be inserted into the lower part of the anterior 
intertrochanteric line; the other passes downward and outward to be inserted 
into the upper part of the same line and the adjacent part of the neck of the 
femur. Between the two bands is a thinner part of the capsule. Sometimes 
there is no division, but the ligament spreads out into a flat, triangular band, 
which is attached below into the whole length of the anterior intertrochanteric 
line. This ligament is frequently called the Y-shaped ligament of Bigelow; and THE HIP-JOINT 
329 
the outer or upper of the two bands is sometimes described as a separate liga- 
ment, under the name of the ilio-trochanteric ligament. 
The Ligamentum Teres, or the Interarticular Ligament (Iigamentum teres femoris) 
(Figs. 236, 237, and 239) is a triangular band implanted by its apex into the 
depression a little behind and below the centre of the head of the femur, and by 
its broad base into the margins of the cotyloid notch, becoming blended with the 
transverse ligament. It is formed of connective tissue, surrounded by a tubular 
sheath of synovial membrane. Sometimes only the synovial fold exists. Very 
rarely it is absent. The ligament is made tense when the hip is semiflexed, 
ILIOLUMBAR LIGAMENT 
ANTERIOR SACRO- 
ILIAC LIGAMENT 
ANTERIOR INFERIOR 
ILIAC SPINE 
FOSSA OF 
'ACETABULUM 
CAPSULAR LIGAMENT, 
FIBROUS PORTION* 
OBTURATOR 
CANAL 
COTYLOID 
'NOTCH 
CAPSULAR LIGAMENT, 
SYNOVIAL PORTION 
/COOPER'S LIGAMENT 
GREAT 
TROCHANTER 
ZONA 
ORBICULARIS 
SPINE OF PUBIS 
ILIOFEMORAL 
ligament 
PUBOFEMORAL 
LIGAMENT 
SMALL 
TROCHANTER 
SYNOVIAL MEMBRANE COVERING 
NECK OF FEMUR 
ZONA ORBICULARIS 
OBTURATOR LIGAMENT 
Fig. 237.-The right hip-joint, seen from before. (Toldt.) 
and the limb adducted and rotated outward; it is, on the other hand, relaxed 
when the limb is abducted. It has, however, but little influence as a ligament, 
though it may to a certain extent limit movement, and would appear to be 
merely a "vestigial and practically useless ligament."1 It is probably a modifi- 
cation of the folds which in other joints fringe the margins of reflection of synovial 
membranes. 
The Cotyloid Ligament (labrum glenoid ale) (Fig. 239) is a fibro-cartilaginous rim 
attached to the margin of the acetabulum, the cavity of which it deepens; at the 
1 J. Bland Sutton. Ligaments: Their Nature and Morphology. 330 
THE ARTICULATION OR JOINTS 
same time it protects the edges of the bone and fills up the inequalities on its sur- 
face. It bridges over the notch as the transverse ligament of the acetabulum, and 
thus forms a complete circle, which closely sur- 
rounds the head of the femur, and assists in 
holding it in its place, acting as a sort of valve. 
It is prismoid on section, its base being attached 
to the margin of the acetabulum and its op- 
posite edge being free and sharp; whilst its 
two surfaces are invested by synovial mem- 
brane, the external one being in contact with 
the capsular ligament, the internal one being 
inclined inward, so as to narrow the acetab- 
ulum and embrace the cartilaginous surface 
of the head of the femur. It is much thicker 
above and behind than below and in front, 
and consists of close, compact fibres, which 
arise from different points of the circumference 
of the acetabulum and interlace with each other 
at very acute angles. 
The transverse ligament of the acetabulum 
(ligamentum transversum acetabuli) (Figs. 236 
and 239) is in reality a portion of the cotyloid 
ligament, though differing from it in having 
no cartilage-cells amongst its fibres. It con- 
sists of strong, flattened fibres, which cross the 
notch at the lower part of the acetabulum and 
convert it into a foramen. Thus an interval 
is left beneath the ligament for the passage of 
nutrient vessels to the joint. 
Synovial Membrane (Figs. 237 and 239).-The synovial membrane is very 
extensive. Commencing at the margin of the cartilaginous surface of the head 
of the femur, it covers all that portion of the neck which is contained within the 
joint; from the neck it is reflected on the internal surface of the capsular liga- 
ment, covers both surfaces of the cotyloid ligament and the mass of fat contained 
in the depression at the bottom of the acetabulum, and is prolonged in the form 
of a tubular sheath around the ligamentum teres, as far as the head of the femur. 
It sometimes communicates through a hole in the capsular ligament between 
the inner band of the Y-shaped ligament and the pubo-femoral ligament with 
a bursa situated on the under surface of the Ilio-psoas muscle. 
The muscles in relation with the joint (Fig. 240) are, in front, the Psoas and 
Iliacus, separated from the capsular ligament by a synovial bursa; above, the 
reflected head of the Rectus and Gluteus minimus, the latter being closely adherent 
to the capsule; internally, the Obturator externus and Pectineus; behind, the Pyri- 
formis, Gemellus superior, Obturator interims, Gemellus inferior, Obturator exter- 
nus, and Quadratus femoris. 
The arteries supplying the joint are derived from the obturator, sciatic, internal 
circumflex, and gluteal. 
The nerves are articular branches from the sacral plexus, great sciatic, obtu- 
rator, accessory obturator, and a filament from the branch of the anterior crural 
supplying the rectus. 
Bursae.-Numerous bursae exist in the neighborhood of the hip-joint. Some 
anatomists have counted twenty-one (Synnestredt). The chief ones are: 1. The 
ilio-pectineal bursa (bursa iliopectinea) (Fig. 240), between the ilio-psoas tendon 
and the capsule of the joint. It often communicates with the hip-joint. 2. The 
Fig. 238 -Hip-joint, showing the ilio-femoral 
ligament. (After Bigelow.) THE HIP-JOINT 
331 
subtendinous iliac bursa (bursa iliaca subtendined), between the tendon of the psoas 
and iliacus and the lesser trochanter. 3. The ischio-gluteal bursa (bursa ischiadica 
m. glutoei maximi), between the Gluteus maximus muscle and the tuberosity of the 
ischium (not constant). 4. The bursa of the great trochanter (bursa trochanterica m. 
glutcei maximi), between the great trochanter and the Gluteus maximus muscle 
near the muscular insertion. 5. Two or three gluteo-femoral bursae (bursce 
glutoeof emorales) below. 6. The obturator bursa (bursa m. obturatorii interni), 
between the margin of the great sacro-sciatic notch and the tendon of the 
Obturator internus muscle. 7. The subcutaneous trochanteric bursa (bursa tro- 
COTYLOID. 
LIGAMENT 
GREAT 
TROCHANTER 
EPIPHYSEAL 
JUNCTION 
LIGAMENTUM 
TERES 
EPIPHYSEAL 
JUNCTION 
TRANSVERSE 
LIGAMENT OF 
ACETABULUM 
ARTICULAR 
CAPSULE 
Fig. 239.-Right hip-joint. Frontal section. Posterior half, viewed from in front. (The joint surfaces 
have been somewhat pulled apart.) (Spalteholz.) 
chanterica subcutanea), between the cutaneous surface and the great trochanter. 
Besides these there is a bursa between the great trochanter and the anterior part 
of the Gluteus medius-between the great trochanter and the posterior part of 
the Gluteus medius-between the great trochanter and the Gluteus minimus- 
beneath the Pyriformis muscle-between the small trochanter and the Quad- 
ratus femoris muscle, and there are bursae beneath the Biceps femoris muscle. 
Actions.-The movements of the hip are very extensive, and consist of flexion, 
extension, adduction, abduction, circumduction, and rotation. THE ARTICULATIONS OR JOINTS 
332 
The hip-joint presents a very striking contrast to the shoulder-joint in the 
much more complete mechanical arrangements for its security and for the limita- 
tion of its movements. In the shoulder, as we have seen, the head of the humerus 
is not adapted at all in size to the glenoid cavity, and is hardly restrained in any 
of its ordinary movements by the capsular ligament. In the hip-joint, on the 
contrary, the head of the femur is closely fitted to the acetabulum for a distance 
extending over nearly half a sphere, and at the margin of the bony cup it is still 
more closely embraced by the cotyloid ligament, so that the head of the femur 
is held in its place by that ligament even when the fibres of the capsule have been 
quite divided (Humphry). The anterior portion of the capsule, described as the 
ilio-femoral ligament, is the strongest of all the ligaments in the body, and is put 
on the stretch by any attempt to extend the femur beyond a straight line with the 
trunk. That is to say, this ligament is the chief agent in maintaining the erect 
position without muscular fatigue; for a vertical line passing through the centre 
of gravity of the trunk falls behind the centres of rotation in the hip-joints, and 
/RECT. FEM 
■Ileo-fem. ligament 
■Bursa 
Iseh. caps, 
ligament. 
Pub. fem. ligament 
Fig. 240.-Relation of muscles to hip-joint. (Henle.) 
therefore the pelvis tends to fall backward, but is prevented by the tension of 
the ilio-femoral and capsular ligaments. The security of the joint may be also 
provided for by the two bones being directly united through the ligamentum 
teres; but it is doubtful whether this so-called ligament can have much influence 
upon the mechanism of the joint. Flexion of the hip-joint is arrested by the soft 
parts of the thigh and abdomen being brought into contact when the leg is flexed 
on the thigh; and by the action of the hamstring muscles when the leg is extended;1 
extension, by the tension of the ilio-femoral ligament and front of the capsule; 
adduction, by the thighs coming into contact; adduction, with flexion by the 
outer band of the ilio-femoral ligament, the outer part of the capsular ligament; 
1 The hip-joint cannot be completely flexed, in most persons, without at the same time flexing the knee, on 
account of the shortness of the hamstring muscles.-Cleland, Jour, of Anat, and Phys., No. 1, Old Series, p. 87. THE HIP-JOINT 
333 
abduction, by the inner band of the ilio-femoral ligament and the pubo-femoral 
band; rotation outward, by the outer band of the ilio-femoral ligament; and 
rotation inward, by the ischio-capsular ligament and the hinder part of the cap- 
sule. The muscles which flex the femur on the pelvis are the Psoas, Iliacus, 
Rectus, Sartorius, Pectineus, Adductor longus and brevis, and the anterior fibres 
of the Gluteus medius and minimus. Extension is mainly performed by the 
Gluteus maximus, assisted by the hamstring muscles. The thigh is adducted by 
the Adductor magnus, longus, and brevis, the Pectineus, the Gracilis, and lower 
part of the Gluteus maximus, and abducted by the Gluteus medius and minimus 
and upper part of the Gluteus maximus. The muscles which rotate the thigh 
inward are the anterior fibres of the Gluteus medius, the Gluteus minimus, and the 
Tensor fasciae femoris; while those which rotate it outward are the posterior fibres 
of the Gluteus medius, the Pyriformis, Obturator externus and internus, Gemellus 
superior and inferior, Quadratus femoris, Iliacus, Gluteus maximus, the three 
Adductors, the Pectineus, and the Sartorius. 
Surface Form.-A line drawn from the anterior superior spinous process of the ilium to 
the most prominent part of the tuberosity of the ischium (Nelaton's line) runs through the 
centre of the acetabulum, and would, therefore, indicate the level of the hip-joint; or, in other 
words, the upper border of the great trochanter, which lies on Nelaton's line, is on a level with 
the centre of the hip-joint. 
Surgical Anatomy.-Inflammation of bursoe about the hip-joint gives rise to confusing 
symptoms. Inflammation of one of the bursae over the great trochanter is not uncommon. 
Great pain is produced if any movement of the gluteal muscles is permitted. 
Enlargement of the bursa over the ischial tuberosity was long called weaver's button. Enlarge- 
ment of the bursa beneath the ilio-psoas may produce a large swelling. Bursal inflammation is 
not unusually mistaken for hip-joint disease 
In dislocation of the hip "the head of the thigh bone may rest at any point around its socket" 
(Bryant); but whatever position the head ultimately assumes, the primary displacement is 
generally downward and inward, the capsule giving way at its weakest-that is, its lower and 
inner-part. The situation that the head of the bone subsequently assumes is determined 
by the degree of flexion or extension, and of outward or inward rotation of the thigh at the 
moment of luxation, influenced, no doubt, by the ilio-femoral ligament, which is not easily 
ruptured. When, for instance, the head is forced backward, this ligament forms a fixed axis, 
round which the head of the bone rotates, and the head is thus driven on to the dorsum of the ilium. 
The ilio-femoral ligament also influences the position of the thigh in the various dislocations: 
in the dislocations backward it is tense, and produces inversion of the limb; in the dislocation 
on to the pubes it is relaxed, and therefore allows the external rotators to evert the thigh; while 
in the thyroid dislocation it is tense and produces flexion. The muscles inserted into the upper 
part of the femur, with the exception of the Obturator internus, have very little direct influence 
in determining the position of the bone. But Bigelow has endeavored to show that the Obtu- 
rator internus is the principal agent in determining whether in the backward dislocations the 
head of the bone shall be ultimately lodged on the dorsum of the ilium or in or near the sciatic 
notch. In both dislocations the head passes, in the first instance, in the same direction; but, 
as Bigelow asserts, in the displacement on to the dorsum, the head of the bone travels up behind 
the acetabulum, in front of the muscle; while in the dislocation into the sciatic notch, the head 
passes behind the muscle, and is therefore prevented from reaching the dorsum, in consequence 
of the tendon of the muscle arching over the neck of the bone, and so remains in the neighbor- 
hood of the sciatic notch. Bigelow, therefore, distinguishes these two forms of dislocation by 
describing them as dislocations backward, "above and below," the Obturator internus. 
The ilio-femoral ligament is rarely torn in dislocations of the hip, and this fact is taken 
advantage of by the surgeon in reducing these dislocations by manipulation. It is made to act 
as a fulcrum to a lever, of which the long arm is the shaft of the femur, and the short arm the 
neck of the bone. 
The hip-joint is rarely the seat of acute synovitis from injury, on account of its deep position 
and its thick covering of soft parts. Acute inflammation may, and does, frequently occur as 
the result of constitutional conditions, as rheumatism, pyaemia, etc. When, in these cases, 
effusion takes place, and the joint becomes distended with fluid, the swelling is not very easy 
to detect on account of the thickness of the capsule and the depth of the articulation. It is 
principally to be found on the front of the joint, just internal to the ilio-femoral ligament; or 
behind, at the lower and back part. In these two places the capsule is thinner than elsewhere. 
Disease of the hip-joint is much more frequently of a chronic character and is usually of tuber- 
culous origin. It begins either in the bones or in the synovial membrane, more frequently in the 334 
THE ARTICULATIONS OR JOINTS 
former, and probably, in most cases, in the growing, highly vascular tissue in the neighborhood 
of the epiphysial cartilage. In this respect it differs very materially from tuberculous arthritis 
of the knee, where the disease often commences in the synovial membrane. The reasons why 
hip-disease so frequently begins near the epiphysial cartilage are twofold: first, this part being 
the centre of rapid growth, its nutrition is unstable and inflammation is easily awakened; 
and, secondly, great strain is thrown upon it, from the frequency of falls and blows upon the hip, 
which causes crushing of the epiphysial cartilage or the cancellous tissue in its neighborhood, 
with the results likely to follow such an injury. In addition to these, the depth of the joint 
protects it from the causes of synovitis. 
In chronic hip-disease the affected limb assumes an altered position, the cause of which it 
is important to understand. In the early stage of a typical case the limb is flexed, abducted, 
and rotated outward. In this position all the ligaments of the joint are relaxed: the front of 
the capsule by flexion; the outer band of the ilio-femoral ligament by abduction; and the inner 
band of this ligament and the back of the capsule by rotation outward. It is, therefore, the 
position of the greatest ease. The condition is not quite obvious at first upon examining a 
patient. If the patient is laid in the supine position, the affected limb will be found to be 
extended and parallel with the other. But it will be found that the pelvis is tilted downward 
on the diseased side and the limb apparently longer than its fellow, and that the lumbar spine 
is arched forward (lordosis). If now the thigh is abducted and flexed, the tilting down- 
ward and the arching forward of the pelvis disappears. The condition is thus explained. A 
limb which is flexed and abducted is obviously useless for progression, and, to overcome the 
difficulty, the patient depresses the affected side of his pelvis in order to produce parallelism 
of his limbs, and at the same time rotates his pelvis on its transverse horizontal axis, so as to 
direct the limb downward instead of forward. In the latter stages of the disease the limb 
becomes flexed, adducted, and inverted. The position probably depends upon muscular 
action, at all events as regards the adduction. The Adductor muscles are supplied by the 
obturator nerve, which also largely supplies the joint. These muscles are therefore thrown into 
reflex action by the irritation of the peripheral terminations of this nerve in the inflamed artic- 
ulation. Osteo-arthritis is not uncommon in the hip-joint, and it is said to be more common in 
the male than in the female, in whom the knee-joint is more frequently affected. It is a disease 
of middle age or more advanced period of life. 
Congenital dislocation is more commonly met with in the hip-joint than in any other articula- 
tion. The displacement usually takes place on to the dorsum ilii. It gives rise to extreme 
lordosis, and a waddling gait is noticed as soon as the child commences to walk. 
Excision of the hip may be required for disease or for injury, especially for gunshot wound. 
It may be performed either by an anterior or an external incision. The former one entails 
less interference with important structures, especially muscles, than the posterior one, but permits 
of less efficient drainage. In these days, however, when the surgeon aims at securing healing 
of his wound without suppuration, this second advantage is not of so much importance. In 
the operation in front the surgeon makes an incision three or four inches in length, starting 
immediately below and external to the anterior superior spinous process of the ilium, down- 
ward and inward between the Sartorius and Tensor fasciae femoris, to the neck of the bone, 
dividing the capsule at its upper part. A narrow-bladed saw now divides the neck of the femur, 
and the head of the bone is extracted with sequestrum forceps. All diseased tissue is carefully 
removed with a sharp spoon or scissors, and the cavity thoroughly flushed with a hot aseptic 
fluid. 
The external method consists in making an incision three or four inches long, commencing 
midway between the top of the great trochanter and the anterior superior spine, and ending 
over the shaft, just below the trochanter. The muscles are detached from the great trochanter, 
and the capsule opened freely. The head and neck are freed from the soft parts and the bone 
sawn through just below the top of the trochanter with a narrow saw. The head of the bone is 
then levered out of the acetabulum. In both operations, if the acetabulum is eroded, it must be 
freely gouged. 
II. The Knee-joint (Articulatio Genu). 
The knee-joint was formerly described as a ginglymus or hinge-joint, but is 
really of a much more complicated character. It must be regarded as consist- 
ing of three articulations in one: one between each condyle of the femur and the 
corresponding tuberosity of the tibia, which are condyloid joints, and one between 
the patella and the femur, which is partly arthrodial, but not completely so, since 
the articular surfaces are not mutually adapted to each other, so that the movement 
is not a simple gliding one. This view of the construction of the knee-joint receives 
confirmation from the study of the articulation in some of the lower mammals, THE KNEE-JOINT 
335 
where three synovial membranes are sometimes found, corresponding to these 
three subdivisions, either entirely distinct or only connected together by small 
communications. This view is further rendered probable by the existence 
of the two crucial ligaments within the joint, which must be regarded as the 
external and internal lateral ligaments of the inner and outer joints respectively. 
The existence of the ligamentum mucosum would further indicate a tendency 
to separation of the synovial cavity into two minor sacs, one corresponding to 
each joint. 
The bones entering into the formation of the knee-joint are the condyles of the 
femur above, the head of the tibia below, and the patella in front. The bones are 
connected together by ligaments, some of which are placed on the exterior of the 
joint, while others occupy its interior. 
External Ligaments. 
Anterior, or Ligamentum Patella?. 
Posterior. 
Internal Lateral. 
Two External Lateral. (The long 
external ligament is constant. The 
short external ligament is not always 
present.) 
Capsular. 
Interior Ligaments. 
Anterior, or External Crucial. 
Posterior, or Internal Crucial. 
Two Semilunar Fibro-cartilages. 
Transverse. 
Coronary. 
Ligamentum mucosum. 
Ligamenta alaria. 
Processes of 
Synovial 
Membrane. 
The Anterior Ligament, or Ligamentum Patellae (Figs. 241, 245, and 246), is the 
central portion of the common tendon of the Extensor muscles of the thigh, which 
is continued from the patella to the tubercle of the tibia, supplying the place of an 
anterior ligament. It is a strong, flat, ligamentous band about three inches in 
length, attached, above, to the apex of the patella and the rough depression on its 
posterior surface; below, to the lower part of the tubercle of the tibia, its superficial 
fibres being continuous over the front of the patella with those of the tendon of the 
Quadriceps extensor. The lateral portions of the tendon of the Extensor muscles 
pass down on either side of the patella, and are attached to the borders of this bone. 
The deep fascia and the quadriceps extensor muscle are inserted into the patella. 
Prolongations from the fascia and from the fibrous expansion of the muscle pass 
from the edges of the patella and from the ligament of the patella to the upper 
extremity of the tibia on each side of the tubercle; externally, and to the head of 
the fibula. They are termed lateral patellar ligaments (retinaculum patellae mediate 
and retinaculum patella: laterale), and merge into the capsule. The posterior 
surface of the ligamentum patellae is separated from the front of the capsular 
ligament by a mass of fat. 
'fhe Posterior Ligament (ligamentum popliteum obliquum') (Fig. 241) is a broad, 
flat, fibrous band, formed of fasciculi separated from one another by apertures 
for the passage of vessels and nerves. It is attached, above, to the upper margin 
of the intercondyloid notch of the femur, and, below, to the posterior margin of 
the head of the tibia. Superficial to the main part of the ligament and forming 
a portion of it is a strong fasciculus derived from the tendon of the Semi- 
membranosus, and passing from the back part of the inner tuberosity of the tibia 
obliquely upward and outward to the back part of the outer condyle of the femur. 
This expansion from the tendon of the Semimembranosus muscle is called the 
posterior ligament of Winslow (ligamentum posticum Winslowii), and it merges 
with the posterior ligament. The posterior ligament forms part of the floor of 
the popliteal space, and the popliteal artery rests upon it. 
'Fhe Internal Lateral Ligament (ligamentum collaterale tibiale) (Figs. 241 and 242) 
is a broad, flat, membranous band, thicker behind than in front, and situated 336 
THE ARTICULATIONS OR JOINTS 
nearer to the back than the front of the joint. It is attached, above, to the inner 
tuberosity of the femur; below, to the inner tuberosity and inner surface of the 
shaft of the tibia to the extent of about two inches. It is crossed, at its lower 
part, by the tendons of the Sartorius, Gracilis, and Semitendinosus muscles, a 
synovial bursa being interposed. Its deep surface covers the anterior portion of 
the tendon of the Semimembranosus, with which it is connected by a few fibres, 
the synovial membrane of the joint, and the inferior internal articular vessels and 
nerve; it is intimately adherent to the internal semilunar fibro-cartilage. 
Fig. 241.-Right knee-joint. Anterior view. 
Fig. 242.-Right knee-joint. Posterior view. 
The External Lateral or Long External Lateral Ligament (ligamentum collaterale 
fibulare) (Figs. 242 and 246) is a strong, rounded, fibrous cord situated nearer 
to the back than the front of the joint. It is attached, above, to the back part 
of the outer tuberosity of the femur; below, to the outer part of the head of the 
fibula. Its outer surface is covered by the tendon of the Biceps, which divides at 
its insertion into two parts, separated by the ligament. The ligament has, pass- 
ing beneath it, the tendon of the Popliteus muscle and the inferior external 
articular vessels and nerve. 
The Short External Lateral Ligament (ligamentum laterale externum breve seu 
posticum) (Fig. 242) is not a constant structure. It is an accessory bundle of 
fibres placed behind and parallel with the preceding, attached, above, to the 
lower and back part of the outer tuberosity of the femur; below, to the summit 
of the styloid process of the fibula. This ligament is intimately connected with 
the capsular ligament, and has, passing beneath it, the tendon of the Popliteus 
muscle and the inferior external articular vessels and nerve. THE KNEE-JOINT 
337 
The Capsular Ligament (capsula articularis) (Fig. 241) consists of an exceedingly 
thin but strong, fibrous membrane which fills in the intervals left between the 
stronger bands above described, and is inseparably connected with them. In front 
it blends with and forms part of the lateral 
patellar ligaments and fills in the interval 
between the anterior and lateral ligaments of 
the joints, with which latter structures it is 
closely connected. It is deficient above the 
joint and beneath the tendon of the quadri- 
ceps extensor. Behind, it is formed chiefly 
of vertical fibres, which arise above from 
the condyles and intercondyloid notch of 
the femur, and is connected below with the 
back part of the head of the tibia, being 
closely united with the origins of the Gas- 
trocnemius, Plantaris, and Popliteus muscles. 
It passes in front of, but is inseparably con- 
nected with, the posterior ligament. 
The Crucial Ligaments (ligament a cruciata 
genu) (Figs. 171, 243, and 244) are two inter- 
osseous ligaments of considerable strength 
situated in the interior of the joint, nearer its 
posterior than its anterior part. They are 
called crucial because they cross each other 
somewhat like the lines of the letter X; and 
have received the names anterior crucial and 
posterior crucial, from the position of their at- 
tachment to the tibia. 
The anterior or external crucial ligament 
(ligamentum cruciatum anterius) (Fig. 243) is 
attached to the depression in front of the 
spine of the tibia, being blended with the anterior extremity of the external 
semilunar fibro-cartilage, and, passing obliquely upward, backward, and out- 
ward, is inserted into the inner and back part of the outer condyle of the femur. 
The posterior or internal crucial ligament (ligamentum cruciatum posterius) 
is stronger, but shorter and less oblique in its direction than the anterior. It 
is attached to the back part 
of the depression behind the 
spine of the tibia, to the pop- 
liteal notch, and to the poste- 
rior extremity of the external 
semilunar fibro-cartilage; and 
passes upward, forward, and 
inward, to be inserted into 
the outer and forepart of the 
inner condyle of the femur. 
It is in relation, in jront, with 
the anterior crucial ligament; 
behind, with the capsular liga- 
ment. 
The Semilunar Fibro-cartil- 
ages(menww) (Figs. 171,243, 
244, 245, and 246) are two crescentic lamellae which serve to deepen the surface 
of the head of the tibia, for articulation with the condyles of the femur. The 
Fig. 243.-Right knee-joint. Showing internal 
ligaments. 
Fig. 244.-Head of tibia, with semilunar cartilages, etc. Seen 
from above. Right side. 338 
THE ARTICULATIONS OR JOINTS 
circumference of each cartilage is thick, convex, and attached to the inside of the 
capsule of the knee; the inner border is thin, concave, and free. Their upper 
surfaces are concave, and in relation with the condyles of the femur; their lower 
surfaces are flat, and rest upon the head of the tibia. Each cartilage covers 
nearly the outer two-thirds of the corresponding articular surface of the tibia, 
leaving the inner third uncovered ; both surfaces are smooth and invested by 
synovial membrane. 
SUPRAPATELLAR 
BURSA 
TENDON OF QUADRICEPS 
EXTENSOR FEMORIS 
MUSCLE 
ARTICULAR 
CAPSULE 
EPI PHYSEAL_ 
junction' 
ARTICULAR 
CAVITY 
LIGAM ENTA 
ALARIA 
LIGAMENTUM 
PATELLXE 
EXTERNAL 
SEMILUNAR 
Fl BRO-CARTI LAGE 
DEEP INFRA- 
PATELLAR BURSA 
EPIPHYSEAL 
junction' 
TUBEROSITY 
OF TIBIA 
Fig. 245.-Right knee-joint. Sagittal section through the external condyle of the femur. Medial half of 
section, from the lateral side. (The knee is slightly flexed; the joint surfaces have been pulled a little apart.) 
(Spalteholz.) 
The internal semilunar fibro-cartilage (meniscus medial is) is nearly semicircular 
in form, a little elongated from before backward, and broader behind than in front; 
its anterior extremity, thin and pointed, is attached to a depression on the anterior 
margin of the head of the tibia, in front of the anterior crucial ligament; its 
posterior extremity is attached to the depression behind the spine, between the 
attachments of the external semilunar fibro-cartilage and the posterior crucial 
ligaments. THE KNEE-JOINT 
339 
The external semilunar fibro-cartilage (meniscus lateralis) forms nearly an 
entire circle, covering a larger portion of the articular surface than the internal 
one. It is grooved on its outer side for the tendon of the Popliteus muscle. Its 
extremities, at their insertion, are interposed between the two extremities of the 
internal semilunar fibro-cartilage; the anterior extremity being attached in front 
of the spine of the tibia to the outer side of, and behind, the anterior crucial 
TENDON OF QUAD- 
RICEPS EXTENSOR 
FEMORIS 
SUPRAPATELLAR 
BURSA 
ARTICULAR 
CAVITY 
PATELLA 
PREPATELLAR 
BURSA 
LONG EXTERNAL^ 
LATERAL- 
LIGAMENT 
EXTERNAL SEMI- 
LUNAR FIBRO- 
CARTILAGE 
TENDON OF 
POPLITEUS" 
MUSCLE 
LIGAMENTUM 
PATELLXE 
POPLITEAL 
BURSA' 
DEEP INFRAPATEL- 
LAR BURSA 
HEAD OF 
FIBULA' 
TUBEROSITIES 
OF TIBIA 
Fig. 246.-Right knee-joint, from the lateral surface. (The joint cavity and several bursae have been injecteu 
with a stiffening medium and then dissected out.) (Spalteholz.) 
ligament, with which it blends; the posterior extremity being attached behind the 
spine of the tibia, in front of the posterior extremity of the internal semilunar 
fibro-cartilage. Just before its insertion posteriorly it gives off a strong fasciculus, 
the ligament of Wrisberg, which passes obliquely upward and outward, to be 
inserted into the inner condyle of the femur, close to the attachment of the poste- 
rior crucial ligament. Occasionally a small fasciculus is given off which passes 
forward to be inserted into the back part of the anterior crucial ligament. The 340 
THE ARTICULATIONS OR JOINTS 
external semilunar fibro-cartilage gives off from its anterior convex margin a 
fasciculus which forms the transverse ligament. 
The Transverse Ligament (ligamentum transversum genu) (Fig. 244) is a band of 
fibres which passes transversely from the anterior convex margin of the external 
semilunar fibro-cartilage to the anterior convex margin of the internal semilunar 
fibro-cartilage; its thickness varies considerably in different subjects, and it is 
sometimes absent altogether. 
The Coronary Ligaments (ligamenta coronaria) are merely portions of the cap- 
sular ligament, which connect the circumference of each of the semilunar fibro- 
cartilages with the margin of the head of the tibia. 
Synovial Membrane (Figs. 245 and 246).-The synovial membrane encloses the 
articular cavity (cavum articulare) of the knee-joint. It is the largest and most 
extensive synovial membrane in the body. Commencing above the upper border 
of the patella, it forms a short cul-de-sac beneath the Quadriceps extensor tendon of 
the thigh, on the lower part of the front of the shaft of the femur; this communi- 
cates, by an orifice of variable size, with a synovial bursa interposed between the 
tendon and the front of the femur (bursa suprapatellaris). On each side of the 
patella the synovial membrane extends beneath the aponeurosis of the Vasti 
muscles, and more especially beneath that of the Vastus internus. Below the 
patella it is separated from the anterior ligament by the anterior part of the 
capsule and a considerable quantity of adipose tissue, known as the infrapatellar 
pad (Fig. 245). In this situation the synovial membrane sends off a triangular 
prolongation, containing a few ligamentous fibres, which extends from the ante- 
rior part of the joint below the patella to the front of the intercondyloid notch. 
This fold has been termed the ligamentum mucosum (plica synovialis patellaris). 
It also sends off two fringe-like folds, called the ligamenta alaria (plicae alares) 
(Fig. 245), which extend from the sides of the ligamentum mucosum, upward 
and laterally between the patella and femur. On either side of the joint it passes 
downward from the femur, lining the capsule to its point of attachment to the 
semilunar cartilages; it may then be traced over the upper surfaces of these car- 
tilages to their free borders, and from thence along their under surfaces to the 
tibia. At the back part of the external one it forms a cul-de-sac between the 
groove on its surface and the tendon of the Popliteus; it surrounds the crucial 
ligaments and lines the inner surface of the ligaments which enclose the joint. 
The pouch of synovial membrane between the Extensor tendon and front of the 
femur is supported, during the movements of the knee, by a small muscle, the 
Subcrureus, which is inserted into the upper part of the capsular ligament. 
The folds of synovial membrane and the fatty processes contained in them act, 
as it seems, mainly in padding to fill up interspaces and obviate concussions. 
Sometimes the bursa beneath the Quadriceps extensor is completely shut off from 
the rest of the synovial cavity, thus forming a closed sac between the Quadriceps 
and the lower part of the front of the femur; sometimes it communicates with the 
synovial cavity by a minute aperture; usually the two cavities are incompletely 
separated by a synovial fold. 
Bursae.-The bursae about the knee-joint are the following: In front there 
are jour bursae: one is interposed between the patella and the skin. It is 
known as the prepatellar bursa (bursa proc patellar is subcutanea); another, of 
small size, between the upper part of the tuberosity of the tibia and the 
ligamentum patellae is called the deep infrapatellar bursa (bursa injrapatellaris 
projunda); and a third between the lower part of the tuberosity of the tibia 
and the skin, the subcutaneous tibial bursa (bursa subcutanea tuberositatis tibiae). 
A fourth bursa exists in front, the suprapatellar bursa (bursa suprapatellaris). 
It lies between the anterior surface of the lower end of the femur and the 
posterior surface of the quadriceps femoris. Spalteholz says that the supra- THE KNEE-JOINT 
341 
patellar bursa is closely connected with the quadriceps tendon and is usually 
incompletely shut off from the cavity of the joint.1 Occasionally there is a 
bursa between the expansion of the fascia lata and the Quadriceps and the 
patella (bursa prapatellaris subfascialis), and sometimes one between the tendon 
of the quadriceps and the anterior surface of the patella (bursa prcepateUaris 
subtendinea). On the outer side there are four bursae: (1) one beneath the outer 
head of the Gastrocnemius (which sometimes communicates with the joint); 
(2) one above the external lateral ligament between it and the tendon of the 
Biceps; (3) one beneath the external lateral ligament between it and the tendon 
of the Popliteus (this is sometimes only an expansion from the next bursa); 
(4) one beneath the tendon of the Popliteus (bursa musculi poplitei) between it 
and the condyle of the femur, which is almost always an extension from the syno- 
vial membrane of the joint. On the inner side there are five bursae: (1) one 
beneath the inner head of the Gastrocnemius, which sends a prolongation between 
the tendons of the Gastrocnemius and Semimembranosus: this bursa often com- 
municates with the joint; (2) one above the internal lateral ligament between it 
and the tendons of the Sartorius, Gracilis, and Semitendinosus; (3) one beneath 
the internal lateral ligament between it and the tendon of the Semimembra- 
nosus: this is sometimes only an expansion from the next bursa; (4) one beneath 
the tendon of the Semimembranosus, between it and the head of the tibia; 
(5) sometimes there is a bursa between the tendons of the Semimembranosus 
and of the Semitendinosus. 
Structures around the Joint.-In front and at the sides, the Quadriceps extensor; 
on the outer side, the tendons of the Biceps and the Popliteus and the external 
popliteal nerve; on the inner side, the Sartorius, Gracilis, Semitendinosus, and 
Semimembranosus; behind, an expansion from the tendon of the Semimembra- 
nosus, the popliteal vessels, and the internal popliteal nerve, the Popliteus, the 
Plantaris, and the inner and outer heads of the Gastrocnemius, some lymphatic 
glands, and fat. 
The arteries supplying the joint are derived from the anastomotica magna 
branch of the femoral, articular branches of the popliteal, anterior and posterior 
recurrent branches of the anterior tibial, and a descending branch from the 
external circumflex of the Profunda. 
The nerves are derived from the obturator, anterior crural, and external and 
internal popliteal. 
Actions.-The knee-joint permits of movements of flexion and extension, and, 
in certain positions, of slight rotation inward and outward. The movement of 
flexion and extension does not, however, take place in a simple, finger-like man- 
ner, as in other joints, but is a complicated movement, consisting of a certain 
amount of gliding and rotation; so that the same part of one articular surface is 
not always applied to the same part of the other articular surface, and the axis 
of motion is not a fixed one. If the joint is examined while in a condition of 
extreme flexion, the posterior part of the articular surfaces of the tibia will be 
found to be in contact with the posterior rounded extremities of the condyles of 
the femur; and if a simple hinge-like movement were to take place, the axis, 
round which the revolving movement of the tibia occurs, would be in the back 
part of the condyle. If the leg is now brought forward into a position of semi- 
flexion, the upper surface of the tibia will be seen to glide over the condyles of 
the femur, so that the middle part of the articular facets are in contact, and the 
axis of rotation must therefore have shifted forward to nearer the centre of the 
condyles. If the leg is now brought into the extended position, a still further 
gliding takes place and a further shifting forward of the axis of rotation. This 
1 Spalteholz's Hand Atlas of Human Anatomy. Translated by Lewellys F. Barker. 342 
THE ARTICULATIONS OR JOINTS 
is not, however, a simple movement, but is accompanied by a certain amount of 
rotation outward round a vertical axis drawn through the centre of the head of 
the tibia. This rotation is due to the greater length of the internal condyle, and 
to the fact that the anterior portion of its articular surface is inclined obliquely 
outward. In consequence of this it will be seen that toward the close of the 
movement of extension-that is to say, just before complete extension is effected 
-the tibia glides obliquely upward and outward over this oblique surface on the 
inner condyle, and the leg is therefore necessarily rotated outward. In flexion 
of the joint the converse of these movements takes place: the tibia glides backward 
round the end of the femur, and at the commencement of the movement the tibia 
is directed downward and inward along the oblique curve of the inner condyle, 
thus causing an inward rotation to the leg. 
During flexion and extension the patella moves on the lower end of the femur, 
but this movement is not a simple gliding one; for if the articular surface of this 
bone is examined, it will be found to present on each side of the central vertical 
ridge two less marked transverse ridges, which divide the surface, except a small 
portion along the inner border, which is cut off by a slight vertical ridge into 
six facets (see Fig. 247), and therefore does not present a uniform curved surface 
as would be the case if a simple gliding movement took 
place. These six facets-three on each side of the 
median vertical ridge-correspond to and denote the 
parts of the bone respectively in contact with the con- 
dyles of the femur during flexion, semiflexion, and exten- 
sion. In flexion only the upper facets on the patella are 
in contact with the condyles of the femur; the lower 
two-thirds of the bone rests upon the mass of fat which 
occupies the space between the femur and tibia. In the 
semiflexed position of the joint the middle facets on the 
patella rest upon the most prominent portion of the con- 
dyles, ami thus afford greater leverage to the Quadriceps 
by increasing its distance from the centre of motion. In 
complete extension the patella is drawn up, so that only 
the lower facets are in contact with the articular sur- 
faces of the condyles. The narrow strip along the inner border is in contact 
with the outer aspect of the internal condyle when the leg is fully flexed at 
the knee-joint. As in the elbow, so it is in the knee-the axis of rotation in 
flexion and extension is not precisely at right angles to the axis of the bone, but 
during flexion there is a certain amount of alteration of plane; so that, whereas in 
flexion the femur and tibia are in the same plane, in extension the one bone forms 
an angle of about 10 degrees with the other. There is, however, this difference 
between the two extremities: that in the upper, during extension, the humeri are 
parallel and the bones of the forearm diverge; in the lower, the femora converge 
below and the tibia are parallel. 
In addition to the slight rotation during flexion and extension, the tibia enjoys 
an independent rotation on the condyles of the femur in certain positions of the 
joint. This movement takes place between the interarticular fibro-cartilages and 
the tibia, whereas the movement of flexion and extension takes place between the 
interarticular fibro-cartilages and the femur. So that the knee may be said to 
consist of two joints, separated by the fibro-cartilages: an upper, menisco-femoral, 
in which flexion and extension take place; and a lower, menisco-tibial, allowing 
of a certain amount of rotation. This latter movement can only take place in the 
semiflexed position of the limb, when all the ligaments are relaxed. 
During flexion the ligamentum patellae is put upon the stretch, as is also the 
posterior crucial ligament in extreme flexion. The other ligaments are all relaxed 
Fig. 247.-View of the pos- 
terior surface of the patella, 
showing diagrammatically the 
areas of contact with the femur 
in different positions of the 
knee. THE KNEE-JOINT 
343 
by flexion of the joint, though the relaxation of the anterior crucial ligament is 
very trifling. During life flexion is checked by the contact of the leg with the 
thigh. In the act of extending the leg upon the thigh the ligamentuni patellae is 
tightened by the Quadriceps extensor; but when the leg is fully extended, as in the 
erect posture, the ligament becomes relaxed, so as to allow free lateral movement to 
the patella, which then rests on the front of the lower end of the femur. The other 
ligaments, with the exception of the posterior crucial, which is partly relaxed, are all 
on the stretch. When the limb has been brought into a straight line, extension is 
checked mainly by the tension of all the ligaments except the posterior crucial and 
ligamentum patellae. The movements of rotation of which the knee is capable are 
permitted in the semiflexed condition by the partial relaxation of both crucial liga- 
ments, as well as of the lateral ligaments. Rotation inward appears to be limited 
by the tension of the anterior crucial ligament, and by the interlocking of the two 
ligaments; but rotation outward does not appear to be checked by either crucial 
ligament, since they uncross during the execution of this movement, but it is 
checked by the lateral ligaments, especially the internal. The main function of 
the crucial ligaments is to act as a direct bond of union between the tibia and 
femur, preventing the former bone from being carried too far backward or 
forward. Thus the anterior crucial ligament prevents the tibia being carried 
too far forward by the extensor tendons, and the posterior crucial checks too 
great movement backward by the flexors. They also assist the lateral ligaments 
in resisting any lateral bending of the joint. The interarticular cartilages are 
intended, as it seems, to adapt the surface of the tibia to the shape of the femur 
to a certain extent, so as to fill up the intervals which would otherwise be felt 
in the varying positions of the joint, and to interrupt the jars which would be 
so frequently transmitted up the limb in jumping or falls on the feet; also to 
permit of the two varieties of motion, flexion and extension, and rotation, as 
explained above. The patella is a great defence to the knee-joint from any 
injury inflicted in front, and it distributes upon a large and tolerably even sur- 
face during kneeling the pressure which would otherwise fall upon the prominent 
ridges of the condyles; it also affords leverage to the Quadriceps extensor muscle 
when it acts upon the tibia; and Mr. Ward has pointed out1 how this leverage 
varies in the various positions of the joint, so that the action of the muscles pro- 
duces velocity at the expense of force in the commencement of extension, and, on 
the contrary, at the close of extension tends to diminish velocity, and therefore 
the shock to the ligaments at the moment tension of the structures takes place. 
Extension of the leg on the thigh is performed by the Quadriceps extensor; 
flexion by the hamstring muscles, assisted by the Gracilis and Sartorius, and, 
indirectly, by the Gastrocnemius, Popliteus, and Plantaris; rotation outward, by 
the Biceps; and rotation inward by the Popliteus, Semitendinosus, and, to a slight 
extent, the Semimembranosus, the Sartorius, and the Gracilis. 
Surface Form.-The interval between the two bones entering into the formation of the knee- 
joint can always easily be felt. If the limb is extended, it is situated on a slightly higher level 
than the apex of the patella; but if the limb is slightly flexed, a knife carried horizontally back- 
ward immediately below the apex of the patella would pass directly into the joint. When the 
knee-joint is distended with fluid, the outline of the synovial membrane at the front of the knee 
may be fairly well mapped out. 
Surgical Anatomy.-The bursa! about the knee are frequently the seat of inflammation. 
Enlargement of the prepatellar bursa constitutes housemaid's knee. The bursa beneath the 
Semimembranosus may enlarge greatly. It communicates with the knee-joint and can frequently 
be made to disappear by pressure when the knee is flexed. Treves points out that enlargement 
of the bursa between the biceps tendon and the external lateral ligament causes great pain 
because the peroneal nerve crosses the sac.'2 
From a consideration of the construction of the knee-joint it would at first sight appear to be 
1 Human Osteology, p. 405. 2 Applied Anatomy. 344 
THE ARTICULATIONS OR JOINTS 
one of the least secure of any of the joints in the body. It is formed between the two longest 
bones, and therefore the amount of leverage which can be brought to bear upon it is very con- 
siderable; the articular surfaces are but ill adapted to each other, and the range and variety of 
motion which it enjoys is great. All these circumstances tend to render the articulation very 
insecure; but, nevertheless, on account of the very powerful ligaments which bind the bones 
together, the joint is one of the strongest in the body, and dislocation from traumatism is of 
very rare occurrence. When, on the other hand, the ligaments have been softened or destroyed 
by disease, partial displacement is very liable to occur, and is frequently brought about by the 
mere action of the muscles displacing the articular surfaces from each other. The tibia may 
be dislocated in any direction from the femur-forward, backward, inward, or outward; or a 
combination of two of these dislocations may occur-that is, the tibia may be dislocated for- 
ward and laterally, or backward and laterally, and any of these dislocations may be complete 
or incomplete. As a rule, however, the antero-posterior dislocations are complete, the lateral 
ones incomplete. 
One or other of the semilunar cartilages may become displaced and nipped between the 
femur and tibia. The accident is produced by a twist of the leg when the knee is flexed, and is 
accompanied by a sudden pain and fixation of the knee in a flexed position. The cartilage may 
be displaced either inward or outward: that is to say, either inward toward the tibial spine, so 
that the cartilage becomes lodged in the intercondyloid notch; or outward, so that the car- 
tilage projects beyond the margin of the articular surface. Acute synovitis, the result of trau- 
matism or exposure to cold, is very common in the knee, on account of its superficial position. 
When distended with fluid, the swelling shows itself above and at the sides of the patella, reach- 
ing about an inch or more above the trochlear surface of the femur, and extending a little higher 
under the Vastus internus than the Vastus externus. Occasionally the swelling may extend 
two inches or more. At the sides of the patella the swelling extends lower at the inner side 
than it does on the outer side. The lower level of the synovial membrane is just above the 
level of the upper part of the head of the fibula. In the middle line it covers the upper third 
of the ligamentum patellae, being separated from it, however, by the capsule and a pad of fat. 
Chronic synovitis principally shows itself in the form of pulpy degeneration of the synovial mem- 
brane, the result of tuberculous arthritis. The reasons why tuberculous disease of the knee 
so often commences in the synovial membrane appear to be the complex and extensive nature of 
this sac; the extensive vascular supply to it; and the fact that injuries are generally diffused 
and applied to the front of the joint rather than to the ends of the bones. Syphilitic disease 
not unfrequently attacks the knee-joint. In the hereditary form of the disease it is usually 
symmetrical, attacking both joints, which become filled with synovial effusion, and is very intract- 
able and difficult to cure. In the tertiary stage of acquired syphilis gummatous infiltration of 
the synovial membrane may take place. The knee is one of the joints most commonly affected with 
osteo-arthritis, and is said to be more frequently the seat of this disease in women than in men. 
The occurrence of the so-called loose cartilage is almost confined to the knee, though loose cartilages 
are occasionally met with in the elbow, and, rarely, in some other joints. Many of them occur in 
cases of osteo-arthritis, in which calcareous or cartilaginous material is formed in one of the synovial 
fringes and constitutes the foreign body, and may or may not become detached, in the former 
case only meriting the usual term, "loose" cartilage. In other cases they have their origin in the 
exudation of inflammatory lymph, and possibly, in some rare instances, a portion of the articular 
cartilage or one of the semilunar cartilages becomes detached and constitutes the foreign body. 
Genu valgum, or knock-knee, is a common deformity of childhood, in which, owing to 
changes in and about the joint, the angle between the outer border of the tibia and femur is 
diminished, so that as the patient stands the two internal condyles of the femora are in contact, 
but the two internal malleoli of the tibiae are more or less widely separated from each other. 
When, however, the knees are flexed to a right angle, the two legs are practically parallel with 
each other. At the commencement of the disease there is a yielding of the internal lateral liga- 
ment and other fibrous structures on the inner side of the joint; as a result of this there is a 
constant undue pressure of the outer tuberosity of the tibia against the outer condyle of the 
femur. This extra pressure causes arrest of growth and, possibly, wasting of the outer con- 
dyle, and a consequent tendency for the tibia to become separated from the internal condyle. 
To prevent this the internal condyle becomes depressed; probably, as was first pointed out by 
Mikulicz, by an increased growth of the lower end of the diaphysis on its inner side, so that the 
line of the epiphysis becomes oblique instead of transverse to the axis of the bone, with a direc- 
tion downward and inward. It is often said that the deformity is produced by undue length 
of the inner condyle, but in reality the condyle grows as the deformity progresses. 
Excision of the knee-joint is most frequently required for tuberculous disease of this articula- 
tion, but is also practised in cases of disorganization of the knee after rheumatic fever, pyaemia, 
etc., in osteo-arthritis, and in ankylosis. It is also occasionally called for in cases of injury, gun- 
shot or otherwise. The operation is best performed either by a horseshoe incision, starting from 
one condyle, descending as low as the tubercle of the tibia, where it crosses the leg, and is then 
carried upward to the other condyle; or by a transverse incision across the patella. In this TIBIO - FIB ULAR ARTICULA TION 
345 
latter incision the patella is either removed or sawn across, and the halves subsequently sutured 
together. The bones having been cleared, and in those cases where the operation is performed 
for tuberculous disease all pulpy tissue having been carefully removed, the section of the femur 
is first made. This should never include, in children, more than, at the most, two-thirds of 
the articular surface, otherwise the epiphysial cartilage will be involved, with disastrous results 
as regards the growth of the limb. Afterward a thin slice should be removed from the upper 
end of the tibia, not more than half an inch. If any diseased tissue still appears to be left in the 
bones, it should be removed with the gouge rather than by making a further section of the bones. 
III. Tibio-fibular Articulation 
(Articulatio Tibiofibularis). 
ANTERIOR 
SUPERIOR 
LIGAMENT 
The articulations between the tibia 
and fibula are effected by ligaments 
which connect both extremities, as 
well as the shafts of the bones. It 
may, consequently, be subdivided 
into three articulations: 1. The 
superior tibio-fibular articulation. 2. 
The middle tibio-fibular ligament or 
interosseous membrane. 3. The 
inferior tibio-fibular articulation. 
TUBEROSITY 
'OF TIBIA 
1. Superior Tibio-fibular Artic- 
ulation (Articulatio 
Tibiofibularis). 
This articulation is an arthrodial 
joint. The contiguous surfaces of 
the bones present two flat, oval 
facets covered with cartilage, and 
connected together by the following 
ligaments: 
Capsular. 
Anterior Superior Tibio-fibular. 
Posterior Superior Tibio-fibular. 
The Capsular Ligament (capsula 
articularis) consists of a membra- 
nous bag which surrounds the artic- 
ulation, being attached around the 
margins of the articular facets on 
the tibia and fibula, and is much 
thicker in front than behind. 
The new nomenclature considers 
the anterior and posterior ligaments 
as one ligament (ligamentum capituli 
fibula). 
The Anterior Superior Ligament 
(Fig. 248) consists of two or three 
broad and flat bands which pass 
obliquely upward and inward from 
the front of the head of the fibula 
to the front of the outer tuberosity 
of the tibia. 
'Phe Posterior Superior Ligament 
(Fig. 241) is a single thick and 
INTEROSSEOUS 
membrane 
INNER 
MALLEOLUS 
OUTER 
malleolus' 
ANTERIOR LIGAMENT 
OF LATERAL 
MALLEOLUS 
Fig. 248.-Ligaments of the right leg, from in front. 
(Spalteholz.) 346 
THE ARTICULATIONS OR JOINTS 
broad band which passes upward and inward from the back part of the head of 
the fibula to the back part of the outer tuberosity of the tibia. It is covered by 
the tendon of the Popliteus muscle. 
Synovial Membrane.-A synovial membrane lines this articulation, which at its 
upper and back part is occasionally continuous with that of the knee-joint. 
2. Middle Tibio-fibular Ligament or Interosseous Membrane 
(Membrana Interossea Cruris) (Fig. 248). 
An interosseous membrane extends between the contiguous margins of the 
tibia, and fibula and separates the muscles on the front from those on the back 
of the leg. It consists of a thin, aponeurotic lamina composed of oblique fibres 
which for the most part pass downward and outward between the interosseous 
ridges on the two bones; some few fibres, however, pass in the opposite direction, 
downward and inward. It is broader above than below. Its upper margin does 
not quite reach the superior tibio-fibular joint, but presents a free concave border, 
above which is a large, oval aperture for the passage of the anterior tibial vessels 
forward to the anterior aspect of the leg. At its lower part is an opening for the 
passage of the anterior peroneal vessels. It is continuous below with the inferior 
interosseous ligament, and is perforated in numerous places for the passage of small 
vessels. It is in relation, in jront, with the Tibialis anticus, Extensor longus digi- 
torum, Extensor proprius hallucis, Peroneus tertius, and the anterior tibial vessels 
and nerve; behind, with the Tibialis posticus and Flexor longus hallucis. 
3. Inferior Tibio-fibular Articulation (Syndesmosis Tibiofibularis) 
(Figs. 250, 251, 252). 
This articulation is formed by the rough, convex surface of the inner side of 
the lower end of the fibula, connected with a concave rough surface on the outer 
side of the tibia. Below, to the extent of about two lines, these surfaces are smooth, 
and covered with cartilage, which is continuous with that of the ankle-joint. The 
ligaments of this joint are- 
Anterior Inferior Tibio-fibular. 
Posterior Inferior Tibio-fibular. 
Transverse or Inferior. 
Inferior Interosseous. 
The Anterior Inferior Ligament {I ig amentum malleoli lateralis anterius) (Figs. 248 
and 252) is a flat, triangular band of fibres, broader below than above, which extends 
obliquely downward and outward, between the adjacent margins of the tibia and 
fibula, on the front aspect of the articulation. It is in relation, in front, with the 
Peroneus tertius, the aponeurosis of the leg, and the integument; behind, with 
the inferior interosseous ligament; and lies in contact with the cartilage covering 
the astragalus. 
The Posterior Inferior Ligament (ligamentum malleoli lateralis posterius) (Fig. 
252), smaller than the preceding, is disposed in a similar manner on the posterior 
surface of the articulation. 
The Transverse Ligament or Inferior Ligament lies under cover of the posterior 
ligament, and is a strong, thick band of yellowish fibres which passes transversely 
across the back of the joint, from the external malleolus to the posterior border of 
the articular surface of the tibia, almost as far as its malleolar process. This liga- 
ment projects below the margin of the bones, and forms part of the articulating 
surface for the astragalus. 
The Inferior Interosseous Ligament (Fig. 250) consists of numerous short, strong, 
fibrous bands which pass between the contiguous rough surfaces of the tibia and 
fibula, and constitute the chief bond of union between the bones. This ligament 
is continuous above with the interosseous membrane. THE TIBIO-TARSAL ARTICULATION 
347 
Synovial Membrane.-The synovial membrane lining the articular surface is 
derived from that of the ankle-joint (Fig. 250). 
Actions.-The movement permitted in these articulations is limited to a very 
slight gliding of the articular surfaces one upon another. 
IV. The Tibio-tarsal Articulation or Ankle-joint (Articulatio Talocruralis) 
(Figs. 249, 250, 251, 252). 
The ankle is a ginglymus or hinge-joint. The bones entering into its formation 
are the lower extremity of the tibia and its malleolus and the external malleolus 
Ankle-joint.- 
Tarsal articulations. 
Ta rso- metatarsal 
articulations. X 
Fig. 249.-Ankle-joint: tarsal and tarso-metatarsal articulations. Internal view. Right side. 
of the fibula, which forms a mortise (Fig. 248) to receive the upper convex surface 
of the astragalus and its two lateral facets. The bony surfaces are covered with car- 
tilage and connected together by a capsule (capsula articularis), which in places 
forms thickened bands constituting the following ligaments: 
Anterior. 
Posterior. 
Internal Lateral. 
External Lateral. 
The Anterior Tibio-tarsal Ligament (ligamentum talotibiale anterius) is a broad, 
thin, membranous layer, attached, above, to the anterior margin of the lower 
extremity of the tibia; below, to the margin of the astragalus, in front of its artic- 
ular surface. It is in relation, in front, with the Extensor tendons of the toes, with 
the tendons of the Tibialis anticus and Peroneus tertius, and the anterior tibial 
vessels and nerve; behind, it lies in contact with the synovial membrane. 
The Posterior Tibio-tarsal Ligament (lig amentum talotibiale posterius) is very 
thin, and consists principally of transverse fibres. It is attached, above, to the 
margin of the articular surface of the tibia, blending with the transverse tibio- 
fibular ligament; below, to the astragalus, behind its superior articular facet. 
Externally, where a somewhat thickened band of transverse fibres is attached to 
the hollow on the inner surface of the external malleolus, it is thicker than inter- 
nallv. THE ARTICULATIONS OR JOINTS 
348 
The Internal Lateral or Deltoid Ligament (ligamentumcalcaneotibialeorligamentum 
deltoideum) (Figs. 249, 250, and 251) is a strong, flat, triangular band, attached, 
above, to the apex and anterior and posterior borders of the inner malleolus. 
The most anterior fibres pass forward to be inserted into the scaphoid bone and 
the inferior calcaneo-scaphoid ligament; the middle descend almost perpendicu- 
larly to be inserted into the sustentaculum tali of the os calcis; and the posterior 
fibres pass backward and outward to be attached to the inner side of the astragalus. 
This ligament is covered by the tendons of the Tibialis posticus and Flexor longus 
digitorum muscles. 
The External Lateral Ligament (ligamenta talofibularia et calcaneofibulare) (Figs. 
251 and 252) consists of three distinctly specialized fasciculi of the capsule, 
taking different directions and separated by distinct intervals; for which reason 
it is described by some anatomists as three distinct ligaments.1 
The anterior fasciculus (ligamentum talofibulare anterius), the shortest of the 
three, passes from the anterior margin of the external malleolus forward and 
inward to the astragalus, in front of its external articular facet. 
INTEROSSEOUS, 
LIGAMENT 
SYNOVIAL. 
ADIPOSE PAD 
INTERNAL LATERAL 
LIGAMENT 
INTEROSSEOUS CAL- 
CAN EO-ASTRAGALOID 
LIGAMENT 
TIBIALIS POSTICUS 
FLEXOR LONGUS 
'digitorum 
PERINEUS- 
BREVIS MUSCLE 
FLEXOR LONGUS 
HALLUCIS 
PERINEUS- 
LONGUS MUSCLE 
POSTERIOR 
TIBIAL VESSELS 
Fig. 250.-Frontal section through the ankle-joint and the calcaneo-astragaloid articulation. 
(Poirier and Charpy). 
The posterior fasciculus (I ig amentum talofibulare posterius), the most deeply seated, 
passes inward from the depression at the inner and back part of the external mal- 
leolus to a prominent tubercle on the posterior surface of the astragalus. Its fibres 
are almost horizontal in direction. 
The middle fasciculus (tigamentum calcaneofibulare) (Figs. 251 and 252), the 
longest of the three, is a narrow, rounded cord passing from the apex of the 
external malleolus downward and slightly backward to a tubercle on the outer 
surface of the os calcis. It is covered by the tendons of the Peroneus longus and 
brevis. 
Synovial Membrane.-The synovial membrane (Fig. 250) invests the inner 
surface of the ligaments, and sends a duplicature upward between the lower 
extremities of the tibia and fibula for a short distance. 
1 Humphry. On the Skeleton, p. 559. THE TIBIO - TARSAL ARTICULATION 
349 
Relations.-The tendons, vessels, and nerves in connection with the joint are, 
in front, from within outward, the Tibialis anticus, Extensor proprius hallucis, 
anterior tibial vessels, anterior tibial nerve, Extensor longus digitorum, and Pero- 
neus tertius; behind, from within outward, the Tibialis posticus, Flexor longus 
n. 
X- 
in. 
IV. 
INTERNAL 
INTEROSSEOUS 
LIGAM ENT 
. V. 
INTEROSSEOUS 
'ligaments 
TARSO- 
M ETATARSAL 
ARTICULATIONS 
INTERMETATARSAL 
ARTICULATIONS 
I NTEROSSEOUS 
LIGAMENT' 
INTEROSSEOUS 
LIGAMENT 
ASTRAGALO- 
SCAPHOID 
ARTICULATION 
CALOANEO-SCAPHOID 
LIGAMENT 
CALCAN EO-CUBOID 
ARTICULATION 
DELTOI D 
LIGAMENT 
INTEROSSEOUS 
LIGAMENT 
ASTRAGALO-CALCANEAL 
"ARTICULATION 
ANKLE-JOINT 
MIDDLE FASCICULUS 
-OF THE EXTERNAL 
LATERAL LIGAMENT 
INFERIOR TIBIO- 
FIBULAR ARTICULATION 
TENDON OF POS- 
TERIOR TIBIAL 
MUSCLE 
Fig. 251.-Joints of the right foot, from the back of the foot. (Spalteholz.) 
digitorum, posterior tibial vessels, posterior tibial nerve, Flexor longus hallucis; 
and in the groove behind the external malleolus, the tendons of the Peroneus 
longus and brevis. 
The arteries supplying the joint are derived from the malleolar branches of 
the anterior tibial and the peroneal. 350 
THE ARTICULATIONS OR JOINTS 
The nerves are derived from the anterior and posterior tibial. 
Actions.-The movements of the joint are those of flexion and extension. 
Flexion consists in the approximation of the dorsum of the foot to the front of the 
leg, while in extension the heel is drawn up and the toes pointed downward. The 
malleoli tightly embrace the astragalus in all positions of the joint, so that any 
slight degree of lateral movement which may exist is simply due to stretching 
of the inferior tibio-fibular ligaments and slight bending of the shaft of the fibula. 
Of the ligaments, the internal, or deltoid, is of very great power-so much so 
that it usually resists a force which fractures the process of bone to which it is 
attached. Its middle portion, together with the middle fasciculus of the external 
lateral ligament, binds the bones of the leg firmly to the foot and resists displace- 
ment in every direction. Its anterior and posterior fibres limit extension and 
flexion of the foot respectively, and the anterior fibres also limit abduction. The 
posterior portion of the external lateral ligament assists the middle portion in 
resisting the displacement of the foot backward, and deepens the cavity for the 
^Inferior tibio-fibular articulation. 
-Ankle-joint. 
Tarsal articulations. 
Tar so- met ata rsal 
articulations. 
Fig. 252.-Ankle-joint: tarsal and tarso-metatarsal articulations. External view. Right side. 
reception of the astragalus. The anterior fasciculus is a security against the dis- 
placement of the foot forward, and limits extension of the joint. The movements 
of inversion and eversion of the foot, together with the minute changes in form by 
which it is applied to the ground or takes hold of an object in climbing, etc., are 
mainly effected in the tarsal joints, the one which enjoys the greatest amount of 
motion being that between the astragalus and os calcis behind and the scaphoid 
and cuboid in front. This is often called the transverse or medio-tarsal joint, and 
it can, with the subordinate joints of the tarsus, replace the ankle-joint in a great 
measure when the latter has become ankylosed. 
Extension of the tarsal bones upon the tibia and fibula is produced by the 
Gastrocnemius, Soleus, Plantaris, Tibialis posticus, Peroneus longus and brevis, 
Flexor longus digitorum, and Flexor longus hallucis; flexion, by the Tibialis anti- 
cus, Peroneus tertius, Extensor longus digitorum, and Extensor proprius hallucis1 
1 The student must bear in mind that the Extensor longus digitorum and Extensor proprius hallucis are 
extensors of the toes, but flexors of the ankle, and that the Flexor longus digitorum and Flexor longus hallucis are 
flexors of the toes, but extensors of the ankle. TILE TIB IO- TARSAL ARTICULATION 
351 
(Fig. 251); inversion, in the extended position, is produced by the Tibialis anticus 
and posticus; and eversion by the Peronei. 
Fig. 253.-Section of the right foot near its inner border, dividing the tibia, astragalus, scaphoid, internal 
cuneiform, and first metatarsal bone, and the first phalanx of the great toe. (After Braune.) 
Surface Form.-The line of the ankle-joint may be indicated by a transverse line drawn 
across the front of the lower part of the leg, about half an inch above the level of the tip of the 
internal malleolus. 
Surgical Anatomy.-Displacement of the trochlear surface of the astragalus from the tibio- 
fibular mortise is not of common occurrence, as the ankle-joint is a very strong and powerful 
articulation, and great force is required to produce dislocation. Nevertheless, dislocation does 
occasionally occur, both in an antero-posterior and a lateral direction. In the latter, which is the 
most common, fracture is a necessary accompaniment of the injury. The dislocation in these cases 
is somewhat peculiar, and is not a displacement in a horizontally lateral direction, such as usually 
occurs in lateral dislocations of ginglymoid joints, but the astragalus undergoes a partial rotation 
round an antero-posterior axis drawn through its own centre, so that the superior surface, instead 
of being directed upward, is inclined more or less inward or outward according to the variety of 
the displacement. 
The ankle-joint is more frequently sprained than any joint in the body, and this may lead 
to acute synovitis. In these cases, when the synovial sac is distended with fluid, the bulging 
appears principally in the front of the joint, beneath the anterior tendons, and on either side, 
between the tibialis anticus and the internal lateral ligament on the inner side, and between the 
Peroneus tertius and the external lateral ligament on the outer side. In addition to this, bulging 
frequently occurs posteriorly, and a fluctuating swelling may be detected on either side of the 
tendo Achillis. 
Chronic synovitis may result from frequent sprains, and when once this joint has been 
sprained it is more liable to a recurrence of the injury than it was before; chronic synovitis 
may be tuberculous in its origin, the disease usually commencing in the astragalus and extending 
to the joint, though it may commence as a synovitis the result probably of some slight strain in 
a tuberculous subject. 
Excision of the ankle-joint is not often performed for two reasons. In the first place, disease 
of the articulation for which this operation is indicated is frequently associated with disease of 
the tarsal bones, which prevents its performance; and, secondly, the foot after excision is fre- 
quently of very little use; far less, in fact, than after a Syme's amputation, which is often, there- 
fore, a preferable operation in these cases. Excision may, however, be attempted in a case of 
tuberculous arthritis in a young and otherwise healthy subject, where the disease is limited to 
the bones forming the joint. It may also be required after injury where the vessels and nerves 
have not been damaged and the patient is young and free from visceral disease. The excision is 
best performed through two lateral incisions. One commencing two and a half inches above the 
external malleolus, carried down the posterior border of the fibula, round the end of the bone, 
and then forward and downward as far as the calcaneo-cuboid joint, midway between the tip 
of the external malleolus and the tuberosity on the fifth metatarsal bone. Through this incision 352 
THE ARTICULATIONS OR JOINTS 
the fibula is cleared, the external lateral ligament is divided, and the bone sawn through about 
half an inch above the level of the ankle-joint and removed. A similar curved incision is now 
made on the inner side of the foot, commmencing two and a half inches above the lower end of 
the tibia, carried down the posterior border of the bone, round the internal malleolus, and for- 
ward and downward to the tuberosity of the scaphoid bone. Through this incision the tibia is 
cleared in front and behind, the internal lateral, the anterior and posterior ligaments divided, 
and the end of the tibia protruded through the wound by displacing the foot outward, and sawn 
off sufficiently high to secure a healthy section of bone. The articular surface of the astragalus 
is now to.be sawn off or the whole bone removed. In cases where the operation is performed 
for tuberculous arthritis the latter course is probably preferable, as the injury done by the saw is 
frequently the starting point of fresh caries; and after removal of the whole bone the shortening 
is not appreciably increased, and the result as regards union appears to be as good as when two 
sawn surfaces of bone are brought into apposition. 
V. Articulations of the Tarsus (Articulationes Intertarseae) (Figs. 249, 
251, 252, 254, 255). 
1. Articulation of the Os Calcis and Astragalus or the Calcaneo- 
astragaloid Articulation (Articulatio Talocalcanea) (Fig. 251). 
The articulations between the os calcis and astragalus are two in number- 
anterior and posterior. They are arthrodial joints. The bones are connected 
together by a capsule (capsula articularis), which is at certain points accentuated 
into definite ligaments. There are five ligaments in this articulation: 
External Calcaneo-astragaloid. Anterior Calcaneo-astragaloid. 
Internal Calcaneo-astragaloid. Posterior Calcaneo-astragaloid. 
Interosseous. 
The External Calcaneo-astragaloid Ligament (ligamentum talocalcaneum laterale) 
(Fig. 252) is a short, strong, fasciculus passing from the outer surface of the 
astragalus, immediately beneath its external malleolar facet, to the outer surface 
of the os calcis. It is placed in front of the middle fasciculus of the external 
lateral ligament of the ankle-joint, with the fibres of which it is parallel. 
The Internal Calcaneo-astragaloid Ligament (ligamentum talocalcaneum mediate) 
is a band of fibres connecting the internal tubercle of the back of the astragalus 
with the back of the sustentaculum tali. Its fibres blend with those of the inferior 
calcaneo-scaphoid ligament. 
The Anterior Calcaneo-astragaloid Ligament (ligamentum talocalcaneum anterius) 
passes from the front and outer surface of the neck of the astragalus to the supe- 
rior surface of the os calcis. 
The Posterior Calcaneo-astragaloid Ligament (ligamentum talocalcaneum postering 
connects the external tubercle of the astragalus with the upper and inner part 
of the os calcis; it is a short band, the fibres of which radiate from their narrow 
attachment to the astragalus. 
The Interosseous Ligament (ligamentum talocalcaneum interosseum) (Figs. 250, 
251, and 255) forms the chief bond of union between the bones. It consists of 
numerous vertical and oblique fibres attached by one extremity to the groove 
between the articulating facets on the under surface of the astragalus; by the 
other to a corresponding depression on the upper surface of the os calcis. It 
is very thick and strong, being at least an inch in breadth from side to side, 
and serves to unite the os calcis and astragalus solidly together. 
Synovial Membrane.-The synovial membranes (Fig. 255) are two in num- 
ber: one for the posterior calcaneo-astragaloid articulation; a second for the 
anterior calcaneo-astragaloid joint. The latter synovial membrane is con- 
tinued forward between the contiguous surfaces of the astragalus and scaphoid 
bones. ARTICULATIONS OF THE TARSUS 
353 
Actions.-The movements permitted between the astragalus and os calcis are 
limited to a gliding of the one bone on the other in a direction from before back- 
ward, and from side to side. 
2. Articulation of the Os Calcis with the Cuboid or the Calcaneo- 
cuboid Articulation (Articulatio Calcaneocuboidea) (Fig. 251). 
In this joint the articular capsule (capsula articularis) is strengthened at 
certain points by definite ligaments. 
The ligaments connecting the os calcis with the cuboid are four in number: 
Dorsal or Superior Calcaneo-cuboid. f Long Calcaneo-cuboid. 
The Internal Calcaneo-cuboid. "° an ar ( Short Calcaneo-cuboid. 
The Superior Calcaneo-cuboid Ligament (ligamentum calcaneocuboideum dorsale) 
(Fig. 252) is a broad portion of the capsule which passes between the contiguous 
surfaces of the os calcis and cuboid on the dorsal surface of the joint. 
The Internal Calcaneo-cuboid or the Interosseous Ligament (pars calcaneo- 
cuboidea ligamenti bifurcati) is a short but thick and strong band of fibres 
arising from the os calcis, in the deep hollow which intervenes between it and 
the astragalus, and closely blended, at its origin, with the superior calcaneo- 
scaphoid ligament. These two ligaments are often regarded as a single bifur- 
cated ligament (ligamentum bifurcation). The internal calcaneo-cuboid liga- 
ment is inserted into the inner side of the cuboid bone. This ligament forms 
one of the chief bonds of union between the first and second rows of the tarsus. 
The Long Calcaneo-cuboid or Long Plantar or Superficial Long Plantar Ligament 
(ligamentum, plantare longum) (Fig. 254), the more superficial of the two plantar 
ligaments, is the longest of all the ligaments of the tarsus: it is attached to 
the under surface of the os calcis, from near the tuberosities, as far forward as 
the anterior tubercle; its fibres pass forward to be attached to the ridge on the 
under surface of the cuboid bone, the more superficial fibres being continued 
onward to the bases of the second, third, and fourth metatarsal bones. This 
ligament crosses the groove on the under surface of the cuboid bone, converting 
it into a canal for the passage of the tendon of the Peroneus longus. 
The Short Calcaneo-cuboid or Short Plantar Ligament (ligamentum calcaneo- 
cuboideum plantare) (Fig. 254) lies nearer the bones than the preceding, from 
which it is separated by a little areolar tissue. It is exceedingly broad, about 
an inch in length, and extends from the tubercle and the depression in front of 
it, on the forepart of the under surface of the os calcis, to the inferior surface of 
the cuboid bone behind the peroneal groove. 
Synovial Membrane (Fig. 255).-The synovial membrane in this joint is distinct. 
It lines the inner surface of the ligaments. 
Actions.-The movements permitted between the os calcis and cuboid are 
limited to a slight gliding upon each other. 
3. The Ligaments Connecting the Os Calcis and Scaphoid or the 
Calcaneo-scaphoid Articulation Ligaments. 
Though these two bones do not directly articulate, they are connected together 
by two ligaments: 
Superior or External Calcaneo-scaphoid. 
Inferior or Internal Calcaneo-scaphoid. 
The Superior or External Calcaneo-scaphoid or Calcaneo-navicular (pars cal- 
caneonavicularis ligamenti bifurcati) arises, as already mentioned, with the 
internal calcaneo-cuboid in the deep hollow between the astragalus and os calcis, 354 
THE ARTICULATIONS OR JOINTS 
constituting a part of the ligamentum bifurcatum; it passes forward from the 
upper surface of the anterior extremity of the os calcis to the outer side of the 
scaphoid bone. These two ligaments resemble the letter Y, being blended together 
behind, but separated in front. 
The Inferior or Internal Calcaneo-scaphoid or Calcaneo-navicular (ligamentum 
calcaneonaviculare plantare) (Fig. 254) is by far the larger and stronger of the two 
ligaments between these bones; it is a broad and thick band of fibres, which 
passes forward and inward from the anterior 
margin of the sustentaculum tali of the os 
calcis to the under surface of the scaphoid 
bone. This ligament not only serves to 
connect the os calcis and scaphoid, but sup- 
ports the head of the astragalus, forming 
part of the articular cavity in which it is 
received. The upper surface presents a 
fibrocartilaginous facet, lined by the syn- 
ovial membrane continued from the ante- 
rior calcaneo-astragaloid articulation, upon 
which a portion of the head of the astragalus 
rests. Its under surface is in contact with 
the tendon of the Tibialis posticus muscle;1 
its inner border is blended with the forepart 
of the Deltoid ligament, thus completing 
the socket for the head of the astragalus. 
Surgical Anatomy.-The inferior calcaneo- 
scaphoid ligament, by supporting the head of the 
astragalus, is principally concerned in maintaining 
the arch of the foot, and when it yields the head of 
the astragalus is pressed downward, inward, and 
forward by the weight of the body, and the foot 
becomes flattened, expanded, and turned outward, 
constituting the disease known as flat-foot. This 
ligament contains a considerable amount of elastic 
fibre, so as to give elasticity to the arch and spring to 
the foot; hence it is sometimes called the "spring" 
ligament. It is supported, on its under surface, by 
the tendon of the Tibialis posticus, which spreads 
out at its insertion into a number of fasciculi which 
are attached to most of the tarsal and metatarsal 
bones; this prevents undue stretching of the ligament 
and is a protection against the occurrence of flat-foot. 
Fig. 254.-Ligaments of the plantar surface 
of the foot. 
4. Articulation of the Astragalus with the Scaphoid Bone or the 
Astragalo-scaphoid Articulation (Articulatio Talonavicularis) 
(Fig. 251). 
The articulation between the astragalus and scaphoid is an arthrodial joint: 
the rounded head of the astragalus being received into the concavity formed by 
the posterior surface of the scaphoid, the anterior articulating surface of the 
calcaneum, and the upper surface of the inferior calcaneo-scaphoid ligament, 
which fills up the triangular interval between these bones. The only ligament of 
this joint is the superior astragalo-scaphoid (Fig. 249). It is a broad band, 
which passes obliquely forward from the neck of the astragalus to the superior 
surface of the scaphoid bone. It is thin, and weak in texture, and covered by the 
Extensor tendons. The inferior calcaneo-scaphoid ligament supplies the place of 
an inferior astragalo-scaphoid ligament. 
1 Mr. Hancock describes an extension of this ligament upward on the inner side of the foot, which completes 
the socket of the joint in that direction (Lancet, 1866, vol. i. p. 618). ARTICULATIONS OF THE TARSUS 
355 
Synovial Membrane (Fig. 255).-The synovial membrane which lines the joint 
is continued forward from the anterior calcaneo-astragaloid articulation. 
Actions.-This articulation permits of considerable mobility, but its feebleness 
is such as to allow occasionally of dislocation of the other bones of the tarsus 
from the astragalus. 
'The transverse tarsal or medio-tarsal joint (articulatio tarsi transversa [Choparti]) 
(Figs. 251 and 256) is formed by the articulation of the os calcis with the cuboid, 
and by the articulation of the astragalus with the scaphoid. The movement which 
takes place in this joint is more extensive than that in the other tarsal joints, and 
consists of a sort of rotation by means of which the sole of the foot may be 
slightly flexed and extended or carried inward (inverted) and outward (everted). 
5. The Articulation of the Scaphoid with the Cuneiform Bones 
(Articulatio Cuneonavicularis) (Fig. 251). 
The scaphoid is connected to the three cuneiform bones by 
Dorsal and Plantar ligaments. 
The Dorsal Ligaments (ligamenta navicularicuneiformia dorsalia) (Figs. 249 and 
251) are small, longitudinal bands of fibrous tissue arranged as three bundles, one 
to each of the cuneiform bones. That bundle of fibres which connects the scaphoid 
with the internal cuneiform is continued round the inner side of the articulation to 
be continuous with the plantar ligament which connects these two bones. 
The Plantar Ligaments (ligamenta navicularicuneijormia plantaria) (Fig. 254) 
have a similar arrangement to those on the dorsum. They are strengthened by 
processes given off from the tendon of the Tibialis posticus. 
Synovial Membrane (Fig. 255).-The synovial membrane of these joints is 
part of the great tarsal synovial membrane. 
Actions.-The movements permitted between the scaphoid and cuneiform 
bones are limited to a slight gliding upon each other. 
6. The Articulation of the Scaphoid with the Cuboid (Articulatio 
CUBONAVICULARIS). 
The scaphoid bone is connected with the cuboid by 
Dorsal, Plantar, and Interosseous ligaments. 
The Dorsal Ligament (ligamentum cuboideonaviculare dorsale) (Fig. 252) con- 
sists of a band of fibrous tissue which passes obliquely forward and outward 
from the scaphoid to the cuboid bone. 
The Plantar Ligament (ligamentum cuboideonaviculare plantare) consists of a 
band of fibrous tissue which passes nearly transversely between these two bones. 
The Interosseous Ligament (Figs. 251 and 255) consists of strong transverse 
fibres which pass between the rough non-articular portions of the lateral sur- 
faces of these two bones. 
Synovial Membrane (Fig. 255).-The synovial membrane of this joint is part 
of the great tarsal synovial membrane. 
Actions.-The movements permitted between the scaphoid and cuboid bones 
are limited to a slight gliding upon each other. 
7. The Articulations of the Cuneiform Bones with Each Other or 
the Intercuneiform Articulations (Fig. 251). 
These bones are connected together by 
Dorsal, Plantar, and Interosseous ligaments. 356 
THE ARTICULATIONS OR JOINTS 
The Dorsal Ligaments (ligamenta inter cuneiformia dorsalia) consist of two bands 
of fibrous tissue which pass transversely, one connecting the internal with the 
middle cuneiform, and the other connecting the middle with the external cunei- 
form. 
The Plantar Ligaments (ligamenta intercuneiformia plantaria) have a similar 
arrangement to those on the dorsum. They are strengthened by the processes 
given off from the tendon of the Tibialis posticus. 
The Interosseous Ligaments (ligamenta intercuneiformia interossea) consist of 
strong transverse fibres which pass between the rough non-articular portions of 
the lateral surfaces of the first and second and the second and third cuneiform 
bones. The outer portion of the third cuneiform is attached to the cuboid by 
the ligamentum cuneocuboideum interosseum. 
Synovial Membrane (Fig. 255).-The synovial membrane of these joints is part 
of the great tarsal synovial membrane. 
Actions.-The movements permitted between the cuneiform bones are limited 
to a slight gliding upon each other. 
8. The Articulation of the External Cuneiform Bone with the 
Cuboid (Fig. 251). 
These bones are connected together by 
Dorsal, Plantar, and Interosseous ligaments. 
The Dorsal Ligament (ligamentum cuneocuboideum dorsale) (Fig. 252) consists 
of a band of fibrous tissue which passes transversely between these two bones. 
The Plantar Ligament (ligamentum cuneocuboideum plantare) has a similar 
arrangement. It is strengthened by a process given off from the tendon of the 
Tibialis posticus. 
The Interosseous Ligament (ligamentum cuneocuboideum interosseum) (Fig. 251) 
consists of strong transverse fibres which pass between the rough non-articular 
portions of the lateral surfaces of the adjacent sides of these two bones. 
Synovial Membrane (Fig. 255).-The synovial membrane of this joint is part 
of the great tarsal synovial membrane. 
Actions.-The movements permitted between the external cuneiform and 
cuboid are limited to a slight gliding upon each other. 
Nerve-supply.-All the joints of the tarsus are supplied by the anterior tibial 
nerve. 
Surgical Anatomy.-In spite of the great strength of the ligaments which connect the tarsal 
bones together, dislocation at some of the tarsal joints does occasionally occur; though, on 
account of the spongy character of the bones, they are more frequently broken than dislocated, 
as the result of violence. When dislocation does occur, it is most commonly in connection with 
the astragalus; for not only may this bone be dislocated from the tibia and fibula at the ankle- 
joint, but the other bones may be dislocated from it, the trochlear surface of the bone remaining 
in situ in the tibio-fibular mortise. This constitutes what is known as the subastragaloid dis- 
location. Or, again, the astragalus may be dislocated from all its connections-from the tibia 
and fibula above, the os calcis below, and the scaphoid in front-and may even undergo a 
rotation, either on a vertical or horizontal axis. In the former case the long axis of the bone 
becoming directed across the joint, so that the head faces the articular surface on one or other 
malleolus; or, in the latter, the lateral surfaces becoming directed upward and downward, so 
that the trochlear surface faces to one or the other side. Finally, dislocation may occur at 
the medio-tarsal joint, the anterior tarsal bones being luxated from the astragalus and cal- 
caneum. The other tarsal bones are also, occasionally, though rarely, dislocated from their 
connections. 
Pes planus, flat-foot, or splay-foot is a condition in which there is abduction, eversion, and 
loss of both the longitudinal and the transverse arch. The head of the astragalus passes down- 
ward and inward; the anterior portion of the foot is turned outward and the inner side of the 
foot is lengthened and broadened. Deformity is increased when standing. In severe cases TARSO - META TARSAL AR TICULA TIONS 
357 
the patient walks on the inner side of the foot. The condition is due to yielding of the tarsal 
ligaments. Abduction is permitted by yielding of the internal lateral and calcaneo-astragaloid 
ligaments. Yielding of the calcaneo-scaphoid ligament permits the head of the astragalus to pass 
downward and forward, and the entire arch falls. Further deformity is induced by the yielding 
of the ligaments. 
VI. Tarso-metatarsal Articulations (Articulationes Tarsometatarseae 
[Lisfranci]) (Figs. 249, 251, 252, 254, 257). 
These are arthrodial joints. The bones entering into their formation are four 
tarsal bones-viz., the internal, middle, and external cuneiform and the cuboid- 
which articulate with the metatarsal bones of the five toes. The metatarsal bone 
of the great toe articulates with the internal cuneiform; that of the second is 
deeply wedged in between the internal and external cuneiform, resting against the 
middle cuneiform, and being the most strongly articulated of all the metatarsal 
bones; the third metatarsal articulates with the extremity of the external cunei- 
form; the fourth, with the cuboid and external cuneiform; and the fifth, with 
the cuboid. The articular surfaces are covered with cartilage, lined by 
synovial membrane, and connected together by capsules and by the following 
ligaments: 
Dorsal. Plantar. Interosseous. 
The Dorsal Ligaments (ligamenta tarsometatarsea dorsalia) consist of strong, 
flat, fibrous bands, which connect the tarsal with the metatarsal bones. The 
first metatarsal is connected to the internal cuneiform by a single broad, thin, 
fibrous band; the second has three dorsal ligaments, one from each cuneiform 
bone; the third has one from the external cuneiform; the fourth has two, one 
from the external cuneiform and one from the cuboid; and the fifth, one from 
the cuboid. 
The Plantar Ligaments (ligamenta tarsometatarsea plantaria) consist of longi- 
tudinal and oblique fibrous bands connecting the tarsal and metatarsal bones, 
but disposed with less regularity than on the dorsal surface. Those for the first 
and second metatarsal are the most strongly marked; the second and third meta- 
tarsal receive strong fibrous bands which pass obliquely across from the internal 
cuneiform; the plantar ligaments of the fourth and fifth metatarsal consist of a 
few scanty fibres derived from the cuboid. 
The Interosseous Ligaments (ligamenta cuneometatarsea interossea) are three in 
number-internal, middle, and external. The internal one is the strongest of the 
three, and passes from the outer extremity of the internal cuneiform to the 
adjacent angle of the second metatarsal. The middle one, less strong than the 
preceding, connects the external cuneiform with the adjacent angle of the second 
metatarsal. The external interosseous ligament connects the outer angle of the 
external cuneiform with the adjacent side of the third metatarsal. 
Synovial Membrane (Fig. 255).-The synovial membrane between the internal 
cuneiform bone and the first metatarsal bone is a distinct sac. The synovial 
membrane between the middle and external cuneiform behind, and the second 
and third metatarsal bones in front, is part of the great tarsal synovial membrane. 
Two prolongations are sent forward from it-one between the adjacent sides of 
the second and third metatarsal bones, and one between the third and fourth 
metatarsal bones. The synovial membrane between the cuboid and the fourth 
and fifth metatarsal bones is a distinct sac. From it a prolongation is sent for- 
ward between the fourth and fifth metatarsal bones. 
Actions.- The movements permitted between the tarsal and metatarsal bones 
are limited to a slight gliding upon each other. 358 
THE ARTICULATIONS OR JOINTS 
VII. Articulations of the Metatarsal Bones with Each Other 
(Articulationes Intermetatarseae) (Figs. 251, 252, 254). 
The base of the first metatarsal bone is not connected with the second meta- 
tarsal bone by any ligaments; in this respect it resembles the thumb. 
The bases of the four outer metatarsal bones are connected together by dorsal, 
plantar, and interosseous ligaments. 
The Dorsal Ligaments (ligamenta basium [055. metatars.] dorsalid) consist of 
bands of fibrous tissue which pass transversely between the adjacent metatarsal 
bones. 
The Plantar Ligaments (ligamenta basium [oss. metatars.] plantar ia) have a 
similar arrangement to those on the dorsum. 
The Interosseous Ligaments (ligamenta basium [055. metatars.] interossed) con- 
sist of strong transverse fibres which pass between the rough non-articular portions 
of the lateral surfaces. 
Synovial Membrane.-The synovial membrane between the second and third 
and the third and fourth metatarsal bones is part of the great tarsal synovial mem- 
brane. The synovial membrane between the fourth and fifth metatarsal bones is 
a prolongation of the synovial membrane of the cubo-metatarsal joint (Fig. 255). 
Actions.-The movement permitted in the tarsal ends of the metatarsal bones 
is limited to a slight gliding of the articular surfaces upon one another. 
The Synovial Membranes in the Tarsal and Metatarsal Joints. 
The synovial membranes (Fig. 255) found in the articulations of the tarsus 
and metatarsus are six in number; one for the posterior calcaneo-astragaloid 
Fig. 255.-Oblique section of the articulations of the tarsus and metatarsus. Showing the six synovial 
membranes. 
articulation; a second for the anterior calcaneo-astragaloid and astragalo- 
scaphoid articulations; a third for the calcaneo-cuboid articulation; and a fourth 
for the articulations of the scaphoid with the three cuneiform, the three cunei- 
form with each other, the external cuneiform with the cuboid, and the middle and 
external cuneiform with the bases of the second and third metatarsal bones, and 
the lateral surfaces of the second, third, and fourth metatarsal bones with each 
other; a fifth for the internal cuneiform with the metatarsal bone of the great toe; 
and a sixth for the articulation of the cuboid with the fourth and fifth metatarsal 
bones. A small synovial membrane is sometimes found between the contiguous 
surfaces of the scaphoid and cuboid bones. ARTICULATIONS OF THE PHALANGES 
359 
Nerve-supply.-The nerves supplying the tarso-metatarsal joints are derived 
from the anterior tibial. 
The digital extremities of all the metatarsal bones are connected together by 
the transverse metatarsal ligament. 
The Transverse Metatarsal Ligament is a narrow fibrous band which passes 
transversely across the anterior extremities of all the metatarsal bones, connecting 
them together. It is blended anteriorly with the plantar (glenoid) ligament of 
each metatarso-phalangeal articulation. To its posterior border is connected the 
fascia covering the Interossei muscles. Its inferior surface is concave where the 
Flexor tendons pass over it. Above it the tendons of the Interossei muscles pass 
to their insertion. It differs from the transverse metacarpal ligament in that it 
connects the metatarsal bone of the great toe with the rest of the metatarsal bones. 
VIII. Metatarso-phalangeal Articulations (Articulationes Metatarso- 
phalangeae). 
The metatarso-phalangeal articulations are of the condyloid kind, formed by 
the reception of the rounded head of the metatarsal bone into a superficial cavity 
in the extremity of the first phalanx. Each joint has a capsule and certain 
other ligaments. 
These ligaments are- 
Plantar. Two Lateral. 
The Plantar Ligaments or the Glenoid Ligaments of Cruveilhier (ligamenia 
accessoria plantaria) are thick, dense, fibrous structures. Each is placed on 
the plantar surface of the joint in the interval between the lateral ligaments, 
to which it is connected. The plantar ligaments are loosely united to the meta- 
tarsal bones, but very firmly to the bases of the first phalanges. The plantar 
surface of each is intimately blended with the transverse metatarsal ligament, 
and, except in the great toe, presents a groove for the passage of the Flexor 
tendons, the sheath surrounding which is connected to each side of the groove. 
The plantar ligament of the great toe contains two large sesamoid bones. By 
their deep surface they form part of the articular surface for the head of the 
metatarsal bone, and are lined by synovial membrane. 
The Lateral Ligaments (ligamenta collateralia) are strong, rounded cords, placed 
one on each side of the joint, each being attached, by one extremity, to the poste- 
rior tubercle on the side of the head of the metatarsal bone; and, by the other, to 
the contiguous extremity of the phalanx. 
The place of a Posterior Ligament is supplied by the extensor tendon over the 
back of the joint. 
Actions.-The movements permitted in the metatarso-phalangeal articulations 
are flexion, extension, abduction, and adduction. 
IX. Articulations of the Phalanges (Articulationes Digitorum Pedis). 
The articulations of the phalanges are ginglymoid joints. Besides the cap- 
sular the ligaments are- 
Plantar. Two Lateral (ligament a collateralia). 
The arrangement of these ligaments is similar to those in the metatarso-phalan- 
geal articulations; the extensor tendon supplies the place of a posterior ligament. 
Actions.-The only movements permitted in the phalangeal joints are flexion 
and extension; these movements are more extensive between the first and second 
phalanges than between the second and third. The movement of flexion is very 
considerable, but extension is limited by the plantar and lateral ligaments. 360 
THE ARTICULATIONS OR JOINTS 
Surface Form.-The principal joints which it is necessary to distinguish, with regard to 
the surgery of the foot, are the medio-tarsal and the tarso-metatarsal. The joint between the 
astragalus and the scaphoid is best found by means of the tubercle of the scaphoid, for 
the line of the joint is immediately behind this process. If the foot is grasped and forcibly 
extended, a rounded prominence, the head of the astragalus, will appear on the inner side of 
the dorsum in front of the ankle-joint, and if a knife is carried downward, just in front of this 
prominence and behind the line of the scaphoid tubercle, it will enter the astragalo-scaphoid 
joint. The calcaneo-cuboid joint is situated midway between the external malleolus and the 
prominent end of the fifth metatarsal bone. The plane of the joint is in the same line as that 
of the astragalo-scaphoid. The position of the joint between the fifth metatarsal bone and the 
cuboid is easily found by the projection of the fifth metatarsal bone, which is the guide to it. 
The direction of the line of the joint is very oblique, so that, if continued onward, it would 
pass through the head of the first metatarsal bone. The joint between the fourth metatarsal, 
bone and the cuboid and external cuneiform is the direct continuation inward of the previous 
joint, but its plane is less oblique; it would be represented by a line drawn from the outer side 
of the articulation to the middle of the first metatarsal bone. The plane of the joint between 
the third metatarsal bone and the external cuneiform is almost transverse. It would be repre- 
CUBOID" 
OS CALCIS" 
ASTRAG. 
FIFTH- 
METATARSAL 
•EXTERNAL 
CUNEIFORM 
ICUBOI Dz 
SCAPHO I D 
FIRST 
METATARSAL 
Fig. 256.-Line of Chopart's amputation. 
(Poirier.) 
Fig. 257.-Line of Lisfranc's amputation. 
(Poirier.) 
sented by a line drawn from the outer side of the joint to the base of the first metatarsal bone. 
The tarso-metatarsal articulation of the great toe corresponds to a groove which can be felt by 
making firm pressure on the inner side of the foot one inch in front of the tubercle on the 
scaphoid bone; and the joint between the second metatarsal bone and the middle cuneiform is 
to be found on the dorsum of the foot, half an inch behind the level of the tarso-metatarsal joint 
of the great toe. The line of the joints between the metatarsal bones and the first phalanges 
is about an inch behind the webs of the corresponding toes. 
Surgical Anatomy.-Chopart's amputation passes through the middle tarsal joint (astragalo- 
scaphoid and calcaneo-cuboid articulation). Fig. 256 shows the line of Chopart. Lisfranc 
amputated at the tarso-metatarsal articulation. Fig. 257 shows the line of Lisfranc. In Hey's 
amputation the fifth, fourth, third, and second metatarsal bones are disarticulated from the 
tarsus and the internal cuneiform is sawn through. In the operation of Forbes, of Toledo, the 
cuneiform bones are disarticulated from the scaphoid, the cuboid is sawn through on a line 
with the surface exposed by the disarticulation. THE MUSCLES AND FASCLE.' 
MYOLOGY is the branch of anatomy which treats of the muscles. The 
muscles are formed of bundles of reddish fibres, endowed with the property 
of contractility. The two principal kinds of muscular tissue found in the 
body are voluntary and involuntary. The former of these, from the character- 
istic appearances which its fibres exhibit under the microscope, is known as 
striated or striped muscle, and from the fact that it is capable of being put into 
action and controlled by the will, as voluntary muscle. The fibres of the latter 
do not present any cross-striped appearance, and for the most part are not 
under the control of the will; hence they are known as unstriated, unstriped, or 
involuntary muscle. The muscular fibres of the heart differ in certain partic- 
ulars from both these groups, and they are therefore separately described as 
cardiac muscular fibres. 
Thus it will be seen that there are three varieties of muscular fibres: (1) 
Transversely striated muscular fibres, which are for the most part voluntary and 
under the control of the will, but some of which are not so, such as the muscles 
of the pharynx and upper part of the oesophagus. This variety of muscle is 
sometimes called skeletal. (2) Transversely striated muscular fibres, which are 
not under the control of the will-i. e., the cardiac muscles. (3) Plain or unstriped 
muscular fibres, which are involuntary and controlled by a different part of the 
nervous system from that which controls the activity of the voluntary muscles. 
Such are the muscular walls of the stomach and intestine, of the uterus and bladder, 
of the blood-vessels, etc. 
In this section we treat of the skeletal or voluntary muscles only. A muscle is 
composed of numerous long, narrow muscle cells which shorten when stimulated. 
The wall of a muscle cell is called the sarcolemma. Muscle cells end either by 
blending with tendon or aponeurosis or else by rounded or tapering extremities, 
which are connected to neighboring cells by means of the sarcolemma. Each 
muscle is composed of bundles or fasciculi of cells or fibres. These bundles are 
connected together by a connective tissue which is known as the epimysium or 
external perimysium (perimysium externum), and which is continuous with the 
sheath of the muscle. Each bundle of muscle fibres is surrounded by the internal 
perimysium (perimysium internum). The internal perimysium joins the external 
perimysium externally and the sarcolemma, or tubular sheath, of each fibre 
internally. 
Each muscle cell (fibre) contains numerous nuclei and also fibrillated striated 
protoplasm. A muscle cell may be 10 cm. in length, and may even extend the 
entire length of a small muscle (Szymonowicz). The diameter of a cell is from 
40/z to 60/2. The striated portion of a cell is differentiated protoplasm, each cell is 
a portion of unchanged protoplasm (sarcoplasm). In man most muscles are of 
1 The Muscles and Fasci® are described conjointly, in order that the student may consider the arrangement 
of the latter in his dissection of the former. It is rare for the student of anatomy in this country to have 
the opportunity of dissecting the fasci® separately; and it is for this reason, as well as from the close con- 
nection that exists between the muscles and their investing sheaths, that they are considered together. Some 
general observations are first made on the histology and anatomy of the muscles and fasci®, the special 
description being given in connection with the different regions. 
361 362 
THE MUSCLES AND FASCIAE 
the red type, but some (mixed muscles) contain red and white fibres. A red 
muscle fibre contains a considerable quantity of sarcoplasm, and the nuclei are 
toward the centre of the cell; in a white muscle fibre there is less sarcoplasm, the 
nuclei are toward the periphery, and striation is very distinct.1 Striation is due 
to alteration in the parts of the fibre, so that the altered material has a different 
refractive index and stains differently from the unaltered portions of the cell. 
The Arteries of voluntary muscles pierce the external perimysium and form 
superficial and deep plexuses that anastomose with each other. These vessels 
follow the trabeculae between the bundles. Branches enter the bundles and 
form capillary plexuses, which here and there possess dilatations for the relief 
of tension during muscular action. 
Veins accompany the arteries, and even the smaller ones possess valves 
(Spalteholz). 
The Nerve Endings in voluntary muscle comprise both motor and sensory ter- 
minations. A motor nerve pierces the external perimysium and breaks up into 
numerous branches to form an interfascicular plexus in the internal perimysium. 
From this plexus nerve fibrils arise and usually one nerve fibril passes to each 
muscle fibre. The nerve fibril pierces the sarcolemma, the neurilemma and 
medullary sheath disappearing before the nerve fibril reaches the muscle fibre, 
and probably being lost by fusing with the sarcolemma. The naked axis-cylinder 
beneath the sarcolemma of a fibre continues to the surface of the muscle fibre and 
undergoes arborization to form an end organ. Around the end organ is a quantity 
of granular sarcoplasm, which, with the nerve end organ, constitutes a sole-plate. 
A sensory nerve takes origin from a muscle spindle, which consists of a bundle 
of encapsuled muscle fibre about sensory nerve twigs. From a muscle spindle 
arise from two to eight large medullated nerve fibres. 
The muscles are connected with the bones, cartilages, ligaments, and skin, 
either directly or through the intervention of fibrous structures called tendons 
or aponeuroses. Where a muscle is attached to bone or cartilage, the fibres ter- 
minate in blunt extremities upon the periosteum or perichondrium, and do not 
come into direct relation with the osseous or cartilaginous tissue. Where muscles 
are connected with the skin, they either lie as a flattened layer beneath it, or are 
connected with its areolar tissue by larger or smaller bundles of fibres, as in the 
muscles of the face. The direct continuation of the tendon of a muscle is known 
as the belly or venter. The origin of a muscle is its head (caput). 
The muscles vary extremely in their form. In the limbs they are of consid- 
erable length, especially the more superficial ones, the deep ones being generally 
broad; they surround the bones and form an important protection to the various 
joints. In the trunk they are broad, flattened, and expanded, forming the parietes 
of the cavities which they enclose; hence the reason of the terms long, broad, 
short, etc., used in the description of a muscle. 
There is a considerable variation in the arrangement of the fibres of certain 
muscles with reference to the tendons to which they are attached. In some, the 
fibres are parallel and run directly from their origin to their insertion; these are 
quadrilateral muscles, such as the Thyro-hyoid. A modification of these is found in 
the fusiform muscles (m. fusiformis), in which the fibres are not quite parallel, but 
slightly curved, so that the muscle tapers at each end; in their action, however, they 
resemble the quadrilateral muscles. Secondly, in other muscles the fibres are con- 
vergent; arising by a broad origin, they converge to a narrower pointed insertion. 
This arrangement of fibres is found in the triangular muscles-e. g., the Temporal. 
Tn some muscles, which otherwise would belong to the quadrilateral or triangular 
type, the origin and insertion are not in the same plane, but the plane of the line 
1 A Text-book of Histology. By Dr. Ladislaus Szymonowicz. Translated and edited by Dr. John Bruce 
MacCallum. APONEUROSES 
363 
of origin intersects that of their insertion; such is the case in the Pectineus muscle. 
Thirdly, in some muscles the fibres are oblique and converge, like the plumes 
of a pen, to one side of a tendon, which runs the entire length of the muscle. 
Such a muscle is rhomboidal or penniform (m. unipennatus), as the Peronei. A 
modification of these rhomboidal muscles is found in those cases where oblique 
fibres converge to both sides of a central tendon which runs down the middle of 
the muscle; these are called bipenniform (in. bipennatus), and an example is afforded 
in the Rectus femoris. Finally, we have muscles in which the fibres are arranged 
in curved bundles in one or more planes, as in an orbicular muscle (m. orbicularis) 
and in that variety of orbicular muscle called a sphincter muscle (m. sphincter). 
The arrangement of the muscular fibres is of considerable importance in respect 
to their relative strength and range of movement. Those muscles where the 
fibres are long and few in number have great range, but diminished strength; 
where, on the other hand, the fibres are short and more numerous, there is 
great power, but lessened range. 
Muscles differ much in size: the Gastrocnemius forms the chief bulk of the 
back of the leg, and the fibres of the Sartorius are nearly two feet in length, whilst 
the Stapedius, a small muscle of the internal ear, weighs about a grain, and its 
fibres are not more than two lines in length. 
The names applied to the various muscles have been derived-1, from their 
situation, as the Tibialis, Radialis, Ulnaris, Peroneus; 2, from their direction, as 
the Rectus abdominis, Obliquus capitis,Transversalis; 3, from their uses, as Flexors, 
Extensors, Abductors, etc.; 4, from their shape, as the Deltoid, Trapezius, Rhom- 
boideus; 5, from the number of their divisions, as the Biceps, the Triceps; 6, 
from their points of attachment, as the Sterno-cleido-mastoid, Sterno-hyoid, 
Sterno-thyroid. 
In the description of a muscle the term origin is meant to imply its more fixed 
or central attachment, and the term insertion, the movable point to which the 
force of the muscle is directed; but the origin is absolutely fixed in only a very 
small number of muscles, such as those of the face, which are attached by one 
extremity to the bone and by the other to the movable integument; the greater 
number of muscles can be made to act from either extremity. 
In the dissection of the muscles the student should pay especial attention to 
the exact origin, insertion, and actions of each, and its more important relations 
with surrounding parts. An accurate knowledge of the points of attachment of 
the muscles is of great importance in the determination of their action. By a 
knowledge of the action of the muscles the surgeon is able to explain the causes 
of displacement in various forms of fracture and the causes which produce dis- 
tortion in various deformities, and, consequently, to adopt appropriate treatment 
in each case. The relations, also, of some of the muscles, especially those in 
immediate apposition with the larger blood-vessels, and the surface-markings they 
produce, should be especially remembered, as they form useful guides to the 
surgeon who operates to expose and ligate them. 
Tendons.-Tendons are white, glistening, fibrous cords, varying in length and 
thickness, sometimes round, sometimes flattened, of considerable strength, and 
devoid of elasticity. They consist almost entirely of white fibrous tissue, the fibrils 
of which have an undulating course parallel with each other and are firmly united 
together. They are very sparingly supplied with blood-vessels, the smaller ten- 
dons presenting in their interior not a trace of them. Nerves also are not present 
in the smaller tendons, but the larger ones, as the tendo Achillis, receive nerves 
which accompany nutrient vessels. The tendons consist principally of a sub- 
stance which yields gelatin. 
Aponeuroses.-Aponeuroses are flattened or ribbon-shaped tendons, of a 
pearly-white color, iridescent, glistening, and similar in structure to the tendons. THE MUSCLES AMD FASCIAE 
364 
They are destitute of nerves, and the thicker ones are only sparingly supplied 
with blood-vessels. 
The tendons and aponeuroses are connected, on the one hand, with the mus- 
cles, and, on the other hand, with movable structures, as the bones, cartilages, 
ligaments, fibrous membranes (for instance, the sclerotic). Where the muscular 
fibres are in a direct line with those of the tendon or aponeurosis, the two are 
directly continuous, the muscular fibre being distinguishable from that of the 
tendon only by its striation. But where the muscular fibres join the tendon or 
aponeurosis at an oblique angle the former terminate, according to Kolliker, in 
rounded extremities, which are received into corresponding depressions on the 
surface of the latter, the connective tissue between the fibres being continuous 
with that of the tendon. The latter mode of attachment occurs in all the penni- 
form and bipenniform muscles, and in those muscles the tendons of which com- 
mence in a membranous form, as the Gastrocnemius and Soleus. 
Fasciae.-The fasciae (fascia, a bandage) are fibro-areolar or aponeurotic 
laminae of variable thickness and strength, found in all regions of the body, 
investing the softer and more delicate organs. The fasciae have been sub- 
divided, from the situation in which they are found, into two groups, superficial 
and deep. 
Superficial Fascia (panniculus adiposus).-The superficial fascia is found imme- 
diately beneath the integument over almost the entire surface of the body. It 
connects the skin with the deep or aponeurotic fascia, and consists of fibro-areolar 
tissue, containing in its meshes pellicles of fat in varying quantity. In the eyelids 
and scrotum, where adipose tissue is rarely deposited, this tissue is very liable to 
serous infiltration. The superficial fascia varies in thickness in different parts 
of the body: in the groin it is so thick as to be capable of being subdivided in 
several laminae. Beneath the fatty layer of the superficial fascia, which is imme- 
diately subcutaneous, there is generally another layer of the same structure, com- 
paratively devoid of adipose tissue, in which the trunks of the subcutaneous vessels 
and nerves are found, as the superficial epigastric vessels in the abdominal region, 
the radial and ulnar veins in the forearm, the saphenous veins in the leg and 
thigh, and the superficial lymphatic glands; certain cutaneous muscles also are 
situated in the superficial fascia, as the Platysma myoides in the neck, and the 
Orbicularis palpebrarum around the eyelids. This fascia is most distinct at the 
lower part of the abdomen, the scrotum, perineum, and extremities; is very thin 
in those regions where muscular fibres are inserted into the integument, as on 
the side of the neck, the face, and around the margin of the anus. It is very 
dense in the scalp, in the palms of the hands and soles of the feet, forming a fibro- 
fatty layer which binds the integument firmly to the subjacent structure. The 
superficial fascia connects the skin to the subjacent parts, facilitates the move- 
ment of the skin, serves as a soft medium for the passage of vessels and nerves 
to the integument, and retains the warmth of the body, since the fat contained in 
its areolae is a bad conductor of heat. 
Degp Fascia.-The deep or aponeurotic fascia is a dense, inelastic, unyielding 
fibrous membrane, forming sheaths for the muscles and affording them broad 
surfaces for attachment. It consists of shining tendinous fibres, placed parallel 
with one another, and connected together by other fibres disposed in a rectilinear 
manner. It is usually exposed on the removal of the superficial fascia, forming a 
strong investment, which not only binds down collectively the muscles in each 
region, but gives a separate sheath to each, as well as to the vessels and nerves. 
The fasciae are thick in unprotected situations, as on the outer side of a limb, and 
thinner on the inner side. The deep fasciae assist the muscles in their action by 
the degree of tension and pressure they make upon their surface; and in certain 
situations this is increased and regulated by muscular action; as, for instance, by MUSCLES AND FASCIAE OF THE CRANIUM AND FACE 
365 
the Tensor fasciae femoris and Gluteus maximus in the thigh, by the Biceps in 
the upper and lower extremities, and Palmaris longus in the hand. In the limbs 
the fasciae not only invest the entire limb, but give off septa which separate the 
various muscles, and are attached beneath to the periosteum: these prolongations 
of fasciae are usually spoken of as' intermuscular septa. 
The Muscles and Fasciae may be arranged, according to the general division 
of the body, into those of the cranium, face, and neck; those of the trunk; those of 
the upper extremity; and those of the lower extremity. 
MUSCLES AND FASCIAE OF THE CRANIUM AND FACE. 
The muscles of the cranium and face consist of ten groups, arranged according 
to the region in which they are situated: 
1. Cranial Region. 
2. Auricular Region. 
3. Palpebral Region. 
4. Orbital Region. 
5. Nasal Region 
6. Maxillary Region. 
7. Mandibular Region. 
8. Intermaxillary Region. 
9. Temporo-mandibular Region. 
10. Pterygo-mandibular Region. 
The muscles contained in each of these groups are the following: 
1. Cranial Region. 
Occipito-frontalis. 
2. Auricular Region. 
Attrahens auriculam. 
Attollens auriculam. 
Retrahens auriculam. 
3. Palpebral Region. 
Orbicularis palpebrarum. 
Corrugator supercilii. 
Tensor tarsi. 
4. Orbital Region. 
Levator palpebrae. 
Rectus superior. 
Rectus inferior. 
Rectus internus. 
Rectus externus. 
Obliquus superior. 
Obliquus inferior. 
5. Nasal Region. 
Pyramidalis nasi. 
Levator labii superioris alaeque 
nasi. 
Dilatator naris posterior. 
Dilatator naris anterior. 
Compressor nasi. 
Compressor narium minor. 
Depressor alae nasi. 
6. Maxillary Region. 
Levator labii superioris. 
Levator anguli oris. 
Zygomaticus major. 
Zygomaticus minor. 
7. Mandibular Region. 
Levator labii inferioris. 
Depressor labii inferioris. 
Depressor anguli oris. 
8. Intermaxillary Region. 
Buccinator. 
Risorius. 
Orbicularis oris. 
9. Temporo-mandibular Region. 
Masseter. 
Temporal. 
10. Pterygo-mandibular Region. 
Pterygoideus externus. 
Pterygoideus internus. 366 
THE MUSCLES AND FASCIA 
1. The Cranial Region. 
Occipito-frontalis. 
Dissection (Fig. 258).-The head being shaved, and a block placed beneath the back of 
the neck, make a vertical incision through the skin from before backward, commencing at 
1. Dissection of scalp. 
2, 3, of auricular region. 
4, 5, 6, of face. 
7, 8, of neck. 
Fig. 258.-Dissection of the head, face, and neck. 
the root of the nose in front, and terminating behind at the occipital protuberance; make a 
second incision in a horizontal direction along the forehead and round the side of the head, 
from the anterior to the posterior extremity of the preceding. Raise the skin in front, from 
the subjacent muscle, from below upward; this must be done with extreme care, removing 
the integument from the outer surface of the vessels and the nerves which lie immediately 
beneath the skin. 
The Skin of the Scalp.-This is thicker than in any other part of the body. It 
is intimately adherent to the superficial fascia, which attaches it firmly to the 
underlying aponeurosis and muscle. Movements of the muscle move the skin. 
The hair-follicles are very closely set together, and extend throughout the whole 
thickness of the skin. It also contains a number of sebaceous glands. 
SUBCUTANEOUS ADI- 
POSE TISSUE 
APONEUROSIS OF 
X>CCI PITO-FRONTALIS 
MUSCLE 
OCCI PITO-FRONTALIS 
MUSCLE 
SUBAPON EUROTIC 
TISSUE 
-PERIOSTEUM 
-OCCIPITO- FRONTALIS 
MUSCLE 
- BONE 
Superficial Fascia.-The superficial fascia in the cranial region is a firm, 
dense, fibro-fatty layer, intimately adherent to the integument, and to the occipito- 
frontalis and its tendinous aponeurosis; it is continuous, behind, with the super- 
Fig. 259.-Epicranial aponeurosis. Antero-posterior section. (Schematic.) (Poirier and Charpy.) THE CRANIAL REGION 
367 
ficial fascia at the back part of the neck; and, laterally, is continued over the 
temporal fascia. It contains between its layers the superficial vessels and nerves 
and much granular fat. 
Surgical Anatomy.-The subcutaneous tissue is composed of bands of fibrous tissue enclos- 
ing spaces filled with fat. The fibrous character of this tissue greatly limits discoloration and 
swelling when inflammation occurs. The edges of a wound which does not involve the apon- 
eurosis or muscle do not retract, hence the wound does not gap. The blood-vessels run practi- 
cally in the skin, and as they lie in very dense tissue and are adherent to it, wounds bleed 
profusely, the arteries being unable to freely contract and retract. It is very difficult or 
impossible to pick up with forceps a vessel in the skin of the scalp, and bleeding must be 
arrested by suture ligatures or by the stitches which close the wound. Sebaceous glands in 
the skin of the scalp may develop into sebaceous cysts (wens). 
The Occipito-frontalis (m. epicranius') (Fig. 260).-The Occipito-frontalis 
is a broad musculo-fibrous layer, which covers the whole of one side of the 
CORRUGATOR SUPERCILII- 
DILATATOR NARIS ANTERIOR. 
DILATATOR NARIS POSTERIOR. 
COMPRESSOR NARIUM MINOR. 
DEPRESSOR AL/E NASI. 
LEVATOR MENTL- 
Fig. 260.-Muscles of the head, face, and neck. 368 
THE MUSCLES AND FASCIA 
vertex of the skull, from the occiput to the eyebrow. It consists of two mus- 
cular slips, separated by an intervening tendinous aponeurosis. The occipital 
portion, the occipitalis muscle (m. occipitalis), is thin, quadrilateral in form, and 
about an inch and a half in length; it arises from the outer two-thirds of the 
superior curved line of the occipital bone, and from the mastoid portion of the 
temporal bone. Its fibres of origin are tendinous, but they soon become muscular, 
and ascend in a parallel direction to terminate in a tendinous aponeurosis. The 
frontal portion, the frontalis muscle (m. frontalis), is thin, of a quadrilateral 
form, and intimately adherent to the superficial fascia. It is broader, its fibres 
are longer, and their structure paler than the occipital portion. Its internal 
fibres are continuous with those of the Pyramidalis nasi. Some anatomists con- 
sider the Pyramidalis muscle as simply the lower fibres of the frontalis, and 
give these bundles of muscle fibre the name of musculus procerus. Its middle 
fibres become blended with the Corrugator supercilii and Orbicularis palpebra- 
rum ; and the outer fibres are also blended with the latter muscle over the external 
angular process. According to Theile, the innermost fibres are attached to the 
nasal bones, the outer to the external angular process of the frontal bone. From 
these attachments the fibres are directed upward, and join the aponeurosis below 
the coronal suture. The inner margins of the frontal portions of the two muscles 
are joined together for some distance above the root of the nose; but between the 
occipital portions there is a considerable, though variable, interval, which is occu- 
pied by the aponeurosis. 
The middle portion of the Occipito-frontalis muscle or the aponeurosis (epi- 
cranial aponeurosis, Galea aponeurotica) covers the upper part of .the vertex 
of the skull, being continuous across the middle line with the aponeurosis of the 
opposite muscle. Behind, it is attached, in the interval between the occipital 
origins, to the occipital protuberance and highest curved lines of the occipital 
bone; in front, it forms a short and narrow prolongation between the frontal por- 
tions; and on each side it has connected with it the Attollens and Attrahens 
auriculam muscles. This aponeurosis is closely connected to the integument by 
the firm, dense, fibro-fatty layer which forms the superficial fascia; it is connected 
with the pericranium by loose cellular tissue, which allows of a considerable 
degree of movement of the integument. It is continuous with the temporal 
fascia below the temporal ridge, and it is in reality the representative of the 
deep fascia. 
Nerves.-The frontal portion of the Occipito-frontalis is supplied by the facial 
nerve; its occipital portion by the posterior auricular branch of the facial. 
Actions.-The frontal portion of the muscle raises the eyebrows and the skin 
over the root of the nose, and at the same time draws the scalp forward, throwing 
the integument of the forehead into transverse wrinkles. The posterior portion 
draws the scalp backward. By bringing alternately into action the frontal and 
occipital portions the entire scalp may be moved forward and backward. In the 
ordinary action of the muscles, the eyebrows are elevated, and at the same time 
the aponeurosis is fixed by the posterior portion, thus giving to the face the 
expression of surprise: if the action is more exaggerated, the eyebrows are still 
further raised, and the skin of the forehead thrown into transverse wrinkles, as in 
the expression of fright or horror. 
Surgical Anatomy.-The skull is covered by the scalp (Fig. 259). This consists of five layers: 
(1) the pericranium; (2) a layer of connective tissue beneath the Occipito-frontalis aponeurosis 
(subaponeurotic tissue); (3) the Occipito-frontalis muscle and aponeurosis; (4) subcutaneous fat; 
(5) skin. If a wound involves the muscle or aponeurosis, it gaps widely, the greatest amount 
of gaping being observed in transverse wounds. The space between the aponeurosis and the 
pericranium is called by Treves the dangerous area of the scalp. It contains a layer of con- 
nective tissue and suppuration in this tissue spreads widely. An abscess in the dangerous area THE AURICULAR REGION 
369 
should be opened above the superior curved line of the occipital bone, above the eyebrow 
or above the zygoma. In a wound or contusion above the aponeurosis but little blood can be, 
effused in the tissue because the fibrous structure prevents it, and abscesses do not tend to 
spread widely. Between the aponeurosis and the pericranium a great amount of blood can be 
effused. An effusion of blood beneath the pericranium is called a cephalhematoma. Such 
a condition may occur from pressure during birth. An extravasation beneath the pericranium 
is limited to the surface of one bone. The pericranium is tightly attached to the sutures, but 
adheres lightly to the surface of the bone, and abscess beneath the pericranium is restricted 
to the surface of one bone. 
2. The Auricular Region (Fig. 260) 
Attrahens auriculam. Attollens auriculam. 
Retrahens auriculam. 
These three small muscles are placed immediately beneath the skin around the 
external ear. In man, in whom the external ear is almost immovable, they are 
rudimentary. They are the analogues of large and important muscles in some 
of the mammalia. 
Dissection.-This requires considerable care, and should be performed in the following 
manner: To expose the Attollens auriculam, draw the pinna, or broad part of the ear, downward, 
when a tense band will be felt beneath the skin, passing from the side of the head to the upper 
part of the concha; by dividing the skin over this band in a direction from below upward, 
and then reflecting it on each side, the muscle is exposed. To bring into view the Attrahens 
auriculam, draw the helix backward by means of a hook, when the muscle will be made 
tense, and may be exposed in a similar manner to the preceding. To expose the Retrahens 
auriculam, draw the pinna forward, when the muscle, being made tense, may be felt beneath 
the skin at its insertion into the back part of the concha, and may be exposed in the same 
manner as the other muscles. 
The Attrahens Auriculam or Aurem (m. auricularis anterior), the smallest of the 
three, is thin, fan-shaped, and its fibres pale and indistinct; they arise from the 
lateral edge of the aponeurosis of the Occipito-frontalis, and converge to be inserted 
into a projection on the front of the helix. 
Relations.-Superficially, with the skin; deeply, with the areolar tissue derived 
from the aponeurosis of the Occipito-frontalis, beneath which are the temporal 
artery and vein and the temporal fascia. 
The Attollens Auriculam or Aurem (m. auricularis superior), the largest of the 
three, is thin and fan-shaped: its fibres arise from the aponeurosis of the Occipito- 
frontalis and converge to be inserted by a thin, flattened tendon into the upper 
part of the cranial surface of the pinna. 
Relations.-Superficially, with the integument; deeply, with the areolar tissue 
derived from the aponeurosis of the Occipito-frontalis, beneath which is the tem- 
poral fascia. 
The Retrahens Auriculam or Aurem (m. auricularis posterior) consists of two or 
three fleshy fasciculi, which arise from the mastoid portion of the temporal bone 
by short aponeurotic fibres. They are inserted into the lower part of the cranial 
surface of the concha. 
Relations.-Superficially, with the integument; deeply, with the mastoid portion 
of the temporal bone and the posterior auricular artery and nerve. 
Nerves.-The Attrahens and Attollens auriculam are supplied by the temporal 
branch of the facial; the Retrahens auriculam is supplied by the posterior auricu- 
lar branch of the same nerve. 
Actions.-In man, these muscles possess very little action: the Attrahens auric- 
ulam draws the ear forward and upward; the Attollens auriculam slightly raises 
it; and the Retrahens auriculam draws it backward. 370 
THE MUSCLES AND FASCIxE 
3. The Palpebral Region (Fig. 260). 
Orbicularis palpebrarum. 
Corrugator supercilii. 
Levator palpebrae. 
Tensor tarsi. 
Dissection (Fig. 257).-In order to expose the muscles of the face, continue the longi- 
tudinal incision made in the dissection of the Occipito-frontalis down the median line of the 
face to the tip of the nose, and from this point onward to the upper lip; and carry another 
incision along the margin of the lip to the angle of the mouth, and transversely across the face 
to the angle of the jaw. Then make an incision in front of the external ear, from the angle of 
the jaw upward, to join the transverse incision made in exposing the Occipito-frontalis. These 
incisions include a square-shaped flap, which should be removed in the direction marked in 
the figure, with care, as the muscles at some points are intimately adherent to the integument. 
The Orbicularis Palpebrarum (m. orbicularis oculi) is a sphincter muscle, which 
surrounds the circumference of the orbit and eyelids. It arises from the internal 
angular process of the frontal bone, from the nasal process of the superior maxil- 
lary bone in front of the lachrymal groove for the nasal duct, and from the anterior 
surface and borders of a short tendon, the tendo oculi, or internal tarsal ligament, 
placed at the inner angle of the orbit. From this origin the fibres are directed 
outward, forming a broad, thin, and flat layer, which covers the eyelids, surrounds 
the circumference of the orbit, and spreads out over the temple and downward on 
the cheek. The internal or palpebral portion (pars palpebralis) of the Orbicularis is 
thin and pale; it arises from the bifurcation of the tendo palpebrarum, and forms 
a series of concentric curves, which are on the outer side of the eyelids inserted into 
the external tarsal ligament. The external or orbital portion (pars orbitalis) is 
thicker and of a reddish color: its fibres are well developed, and form complete 
ellipses. The upper fibres of this portion blend with the Occipito-frontalis and 
Corrugator supercilii. 
Relations.-By its superficial surface, with the integument. By its deep surface, 
above, with the Occipito-frontalis and Corrugator supercilii, with which it is inti- 
mately blended, and with the supraorbital vessels and nerve; below, it covers the 
lachrymal sac, and the origin of the Levator labii superioris abeque nasi, the 
Levator labii superioris, and the Zygomaticus minor muscles. Internally, it is 
occasionally blended with the Pyramidalis nasi. Externally, it lies on the temporal 
fascia. On the eyelids it is separated from the conjunctiva by the Levator palpe- 
bne, the tarsal ligaments, the tarsal plates, and the Meibomian glands. 
The tendo oculi or internal tarsal ligament (Uyamentum palpebrale mediate) is a 
short tendon, about two lines in length and one in breadth, attached to the nasal 
process of the superior maxillary bone in front of the lachrymal groove. Crossing 
the lachrymal sac, it divides into two parts, each division being attached to the 
inner extremity of the corresponding tarsal plate. As the tendon crosses the lach- 
rymal sac, a strong aponeurotic lamina is given off from the posterior surface, 
which expands over the sac, and is attached to the ridge on the lachrymal bone. 
This is the reflected aponeurosis of the tendo oculi. 
The external tarsal ligament (raphe palpebralis lateralis) is a much weaker struc- 
ture than the tendo oculi. It is attached to the margin of the frontal process of 
the malar bone, and passes inward to the outer commissure of the eyelids; it 
connects together the outer extremities of the two tarsal cartilages. 
Use of Tendo Oculi.-Besides giving attachment to part of the Orbicularis 
palpebrarum and to the tarsal plates, it serves to suck the tears into the lachrymal 
sac, by its attachment to the sac. Thus, each time the eyelids are closed, the tendo 
oculi becomes tightened, through the action of the Orbicularis, and draws the wall 
of the lachrymal sac outward and forward, so that a vacuum is made in the sac, 
and the tears are sucked along the lachrymal canals into it. THE PALPEBRAL REGION 
371 
The Corrugator Supercilii (Figs. 259 and 260) is a small narrow, pyramidal 
muscle, placed at the inner extremity of the eyebrow, beneath the Occipito- 
frontalis and Orbicularis palpebrarum muscles. It arises from the inner extrem- 
ity of the superciliary ridge, from whence its fibres pass upward and outward, 
and are inserted into the deep surface of the skin, opposite the middle of the 
orbital arch. 
Relations.-By its anterior surface with the Occipito-frontalis and Orbicularis 
palpebrarum muscles; by its posterior surface, with the frontal bone and supra- 
trochlear nerve. 
The Levator Palpebrae will be described with the muscles of the orbital region. 
The Tensor Tarsi or Homer's Muscle (pars lacrimalis of the orbicularis pal- 
pebrarum) (Fig. 261) is a small thin muscle about three lines in breadth and six 
in length, situated at the inner side of the orbit, behind the tendo oculi. It is 
usually considered to be composed of fibres derived from the Orbicularis palpe- 
brarum. It arises from the crest and adjacent part of the orbital surface of the 
FRONTAL SINUS 
CORRUGATOR 
SUPERCI Lil 
PALPEBRAL PORTION 
OF ORBICULARIS 
PALPEBRARUM 
ORBITAL 
'arch 
PUNCTA 
LACHRYMALIA 
TENSOR 
"TARSI 
LACHRYMAL 
SAC 
-LACHRYMAL 
GROOVE 
ORBITAL PORTION OF 
ORBICULARIS PALPEBRARUM 
ANTRUM OF 
HIGHMORE 
Fig. 261.-The three portions of the Orbicularis palpebrarum muscle, and the relation of this muscle to the 
Corrugator supercilii muscle, seen from behind. (Left side.) (Toldt.) 
lachrymal bone, and, passing across the lachrymal sac, divides into two slips, 
which cover the lachrymal canals and are inserted into the tarsal plates internal 
to the puncta lachrymalia. Its fibres appear to be continuous with those of the 
palpebral portion of the Orbicularis palpebrarum; it is occasionally very indistinct. 
Nerves.-The Orbicularis palpebrarum, Corrugator supercilii, and Tensor tarsi 
are supplied by the facial nerve. Recent investigations tend to show that the 
Orbicularis palpebrarum, Corrugator supercilii, and frontal part of the Occipito- 
frontalis are in reality supplied by fibres of the third nerve, which descend through 
the pons varolii to join the facial nerve. 
Actions.-The Orbicularis palpebrarum is the sphincter muscle of the eyelids. 
The palpebral portion acts involuntarily, closing the lids gently, as in sleep or in 
blinking; the orbicular portion is subject to the will. When the entire muscle is 
brought into action, the skin of the forehead, temple, and cheek is drawn inward 
toward the inner angle of the orbit, and the eyelids are firmly closed as in photo- 372 
THE MUSCLES AND FASCIAE 
phobia. When the skin of the forehead, temple, and cheek is thus drawn inward 
by the action of the muscle it is thrown into folds, especially radiating from the 
outer angle of the eyelids, which give rise in old age to the so-called "crow's feet." 
The Levator palpebrae is the direct antagonist of this muscle; it raises the upper 
eyelid and exposes the globe. The Corrugator supercilii draws the eyebrow 
downward and inward, producing the vertical wrinkles of the forehead. It is the 
" frowning" muscle, and may be regarded as the principal agent in the expression 
of suffering. The Tensor tarsi draws the eyelids inward and compresses the eye- 
lids and the extremities of the lachrymal canals against the surface of the globe 
of the eye; thus placing the canals in the most favorable situation for receiving 
the tears. It serves, also, to compress the lachrymal sac. 
4. The Orbital Region (Fig. 262). 
Levator palpebne superioris. Rectus internus. 
Rectus superior. Rectus externus. 
Rectus inferior. Obliquus oculi superior. 
Obliquus oculi inferior. 
Dissection.-To open the cavity of the orbit, remove the skull-cap and brain; then saw 
through the frontal bone at the inner extremity of the supraorbital ridge, and externally at its 
junction with the malar. Break in pieces the thin roof of the orbit by a few slight blows of 
the hammer, and take it away; drive forward the superciliary portion of the frontal bone 
Fig. 262.-Muscles of the right orbit. 
by a smart stroke, but do not remove it, as that would destroy the pulley of the Obliquus 
superior. When the fragments are cleared away, the periosteum of the orbit will be exposed; 
this being removed, together with the fat which fills the cavity of the orbit, the several muscles 
of this region can be examined. The dissection will be facilitated by distending the globe 
of the eye. In order to effect this, puncture the optic nerve near the eyeball with a curved 
needle, and push the needle onward into the globe; insert the point of a blowpipe through 
this aperture, and force a little air into the cavity of the eyeball; then apply a ligature round 
the nerve so as to prevent the air escaping. The globe being now drawn forward, the muscles 
will be put upon the stretch. 
The Levator Palpebrse Superioris is thin, flat, and triangular in shape. It 
arises from the under surface of the lesser wing of the sphenoid, above and in 
front of the optic foramen, from which it is separated by the origin of the Superior 
rectus (Fig. 263). At its origin it is narrow and tendinous, but soon becomes 
broad and fleshy, and finally terminates in a wide aponeurosis, which is inserted 
into the upper margin of the superior tarsal plate. From this aponeurosis a thin 
expansion is continued onward, passing between the fibres of the Orbicularis THE ORBITAL REGION 
373 
to be inserted into the skin of the hd, and some deeper fibres blend with an 
expansion from the sheath of the Superior rectus muscle, and are with it pro- 
longed into the conjunctiva. 
Relations.-By its upper surface, with the frontal nerve and supraorbital 
artery, the periosteum of the orbit and lachrymal gland; and, in the lid, with the 
inner surface of the tarsal ligament; by its under surface, with the Superior rectus, 
and, in the lid, with the conjunctiva. A small branch of the third nerve enters 
its under surface. 
The Superior Rectus (m. rectus superior), the thinnest and narrowest of the 
four Recti, arises from the upper margin of the optic foramen (Tig. 263) beneath 
the Levator palpebrte, and from the fibrous sheath of the optic nerve; and is 
inserted by a tendinous expansion into the sclerotic coat, about three or four 
lines from the margin of the cornea. 
Relations.-By its upper surface, with the Levator palpebrse; by its under sur- 
face, with the optic nerve, the ophthalmic artery, the nasal nerve, and the branch 
of the third nerve which supplies it; and, in front, with the tendon of the Superior 
oblique and the globe of the eye. 
The Inferior Rectus (m. rectus inferior) and the Internal Rectus (m. rectus 
medialis) arise by a common tendon, the ligament of Zinn1 (annulus tendineus 
communis), which is attached round the circumference of the optic foramen, 
except at its upper and outer part (Fig. 263). 
The External Rectus (m. rectus lateralis) has two heads: the upper one arises 
from the outer margin of the optic foramen immediately beneath the Superior 
rectus; the lower head, partly from the ligament of Zinn and partly from a small 
pointed process of bone on the lower margin 
of the sphenoidal fissure (Fig. 263). Each 
muscle passes forward in the position implied by 
its name, to be inserted by a tendinous expan- 
sion, the tunica albuginea, into the sclerotic coat, 
about three or four lines from the margin of 
the cornea. Between the two heads of the Ex- 
ternal rectus is a narrow interval, through 
which passes the third, the nasal branch of 
the ophthalmic division of the fifth and sixth 
nerves, and the ophthalmic vein. Although 
nearly all of these muscles present a common 
origin and are inserted in a similar manner 
into the sclerotic coat, there are certain differences to be observed in them as 
regards their length and breadth. The Internal rectus is the broadest, the 
External is the longest, and the Superior is the thinnest and narrowest. 
The Superior Oblique (m. obliquus superior) is a fusiform muscle placed at the 
upper and inner side of the orbit, internal to the Levator palpebrse. It arises 
about a line above the inner margin of the optic foramen (Fig. 263), and, pass- 
ing forward to the inner angle of the orbit, terminates in a rounded tendon, 
which plays in a ring or pulley, the trochlea (trochlea m. obliqui superioris), 
formed by a cartilaginous tissue attached to a depression beneath the internal 
angular process of the frontal bone, the contiguous surfaces of the tendon and 
ring being lined by a delicate synovial membrane and enclosed in a thin fibrous 
investment. The tendon is reflected backward, outward, and downward beneath 
the Superior rectus to the outer part of the globe of the eye, and is inserted into 
Levator 
palpebroe superior. 
Rectus superior. 
Obliquus superior. 
Rectus 
internus. 
Its upper head. 
Rectus inferior. 
'Lower head. 
Fig. 263.- The relative position and attach- 
ment of the muscles of the left eyeball. 
1 The ligament of Zinn ought, perhaps more appropriately, to be termed the aponeurosis or tendon of Zinn, 
Mr. C. B. Lockwood has described a somewhat similar structure on the under surface of the Superior rectus 
muscle, which is attached to the lesser wing of the sphenoid, forming the upper and outer margin of the optic 
foramen. This superior tendon gives origin to the Rectus superior, the superior head of the External rectus, 
and the upper part of the Internal rectus.-Journal of Anatomy and Physiology, vol. xx. part i. p. 1. THE MUSCLES AND FASCIAE 
374 
the sclerotic coat, behind the equator of the eyeball, the insertion of the muscle 
lying between the Superior and External recti. 
Relations.-By its upper surface, with the periosteum covering the roof of the 
orbit and the fourth nerve: the tendon, where it lies on the globe of the eye, 
is covered by the Superior rectus; by its under surface, with the nasal nerve, 
ethmoidal arteries, and the upper border of the internal rectus. 
The Inferior Oblique (m. obliquus inferior) is a thin, narrow muscle placed near 
the anterior margin of the orbit. It arises from a depression on the orbital plate 
of the superior maxillary bone, external to the lachrymal groove (Fig. 262). 
Passing outward, backward, and upward between the Inferior rectus and the 
floor of the orbit, and then between the eyeball and the External rectus, it is 
inserted into the outer part of the sclerotic coat between the Superior and External 
recti, near to, but somewhat behind, the tendon of insertion of the Superior oblique. 
Relations.-By its ocular surface, with the globe of the eye and with the Inferior 
rectus; by its orbital surface, with the periosteum covering the floor of the orbit, 
and with the External rectus. Its borders look forward and backward; the poste- 
rior one receives a branch of the third nerve. 
The orbital muscle or Muller's muscle (musculus orbitalis), which spans the 
spheno-maxillary fissure and infraorbital groove, is composed of non-striated 
fibres, and is a rudimentary structure continuous with the periosteum of the orbit.1 
Nerves.-The Levator palpebrae, Inferior oblique, and all the Recti excepting 
the External, are supplied by the third nerve; the Superior oblique, by the fourth; 
the External rectus, by the sixth. 
Actions.-The Levator palpebrae raises the upper eyelid, and is the direct 
antagonist of the Orbicularis palpebrarum. The four Recti muscles are attached 
in such a manner to the globe of the eye that, acting singly, they will turn it either 
upward, downward, inward, or outward, as expressed by their names. The 
movement produced by the Superior or Inferior rectus is not quite a simple one, 
for, inasmuch as they pass obliquely outward and forward to the eyeball, the 
elevation or depression of the cornea must be accompanied by a certain deviation 
inward, with a slight amount of rotation, which, however, is corrected by the 
Oblique muscles, the Inferior oblique correcting the deviation inward of the 
Superior rectus, and the Superior oblique that of the Inferior rectus. The con- 
traction of the External and Internal recti, on the other hand, produces a purely 
horizontal movement. If any two contiguous recti of one eye act together, they 
carry the globe of the eye in the diagonal of these directions-viz., upward and 
inward, upward and outward, downward and inward, or downward and outward. 
The movement of circumduction, as in looking round a room, is performed by 
the alternate action of the four Recti. The Oblique muscles rotate the eyeball 
on its antero-posterior axis, this kind of movement being required for the correct 
viewing of an object when the head is moved laterally, as from shoulder to shoidder, 
in order that the picture may fall in all respects on the same part of the retina of 
each eye.2 It should be noted that sometimes the corresponding Recti and some- 
times the opposite ones of the two eyes act together; for instance, the two superior 
and inferior Recti carry both eyeballs upward and downward, respectively. In 
looking toward the right the right External and left Internal recti act together, 
the reverse being the case in looking toward the left. In turning both eyes toward 
the middle line, as in directing our vision toward an object less than twenty feet 
distant, the two internal recti act together. 
Fasciae of the Orbit.-The connective tissue of the orbit is in various places 
condensed into thin membranous layers, which may be conveniently described as 
1 See F. Groyer, in the Vienna Sitzungsberichte der Kaiserlichen Akademie derWissenschaften, 1903, Band cxii. 
2 On the Oblique Muscles of the Eye in Man and Vertebrate Animals, by John Struthers, M.D., in Anatom- 
ical and Physiological Observations. For a fuller account of the various co-ordinate actions of the muscles of 
a single eye and of both eyes than our space allows see Dr. M. Foster's Text-book of Physiology. THE NASAL REGION 
375 
(1) the orbital fascia; (2) the sheaths of the muscles; and (3) the covering of the 
eyeball. 
(1) The Orbital Fascia.-This forms the periosteum of the orbit. It is loosely 
connected to the bones, from which it can be readily separated. Behind, it is 
connected with the dura mater by processes which pass through the optic foramen 
and sphenoidal fissure, and with the sheath of the optic nerve. In front it is 
connected with the periosteum at the margin of the orbit, and sends off a process 
which assists in forming the palpebral fascia. From its internal surface two 
processes are given off-one to enclose the lachrymal gland, the other to hold the 
pulley of the Superior oblique muscle in position. 
(2) The Sheaths of the Muscles.-The sheaths of the muscles give off expansions 
to the margins of the orbit which limit the action of the muscles. 
(3) The Covering of the Eyeball - Tenon's capsule-surrounds the posterior 
two-thirds of the eyeball; it will be described in the sequel. 
Surgical Anatomy.-The position and exact point of insertion of the tendons of the 
Internal and External recti muscles into the globe should be carefully examined from the front 
of the eyeball, as the surgeon is often required to divide the one or the other muscle for the cure 
of strabismus (squint). In convergent strabismus, which is the more common form of the disease, 
the eye is turned inward, requiring the division of the Internal rectus. In the divergent form, 
which is more rare, the eye is turned outward, the External rectus being especially implicated. 
The deformity produced in either case is to be remedied by division of one or the other muscle. 
The operation is thus performed: The lids are to be well separated; the eyeball being rotated 
outward or inward, the conjunctiva should be raised by a pair of forceps and divided immediately 
beneath the lower border of the tendon of the muscle to be divided, a little behind its insertion 
into the sclerotic; the submucous areolar tissue is then divided, and into the small aperture 
thus made a blunt hook is passed upward between the muscle and the globe, and the tendon of 
the muscle and conjunctiva covering it divided by a pair of blunt-pointed scissors. Or the 
tendon may be divided by a subconjunctival incision, one blade of the scissors being passed 
upward between the tendon and the conjunctiva, and the other between the tendon and the 
sclerotic. The student, when dissecting these muscles, should remove on one side of the subject 
the conjunctiva from the front of the eye, in order to see more accurately the position of the 
tendons, while on the opposite side the operation may be performed. Inflammation of the 
synovial membrane lining the trochlea of the Superior oblique may lead to the formation of 
a cyst of considerable size. 
In performing enucleation of the eyeball the conjunctiva is clipped with scissors near the 
cornea and the capsule of Tenon is divided with it. One rectus muscle after another is caught 
up on a blunt hook and divided. The scissors are now pushed well in along the outer orbital 
wall and the optic nerve is divided. Finally the oblique muscles, the ciliary vessels and nerves, 
and fragments of tissue helping to retain the globe are cut and the eyeball is enucleated. 
An orbital abscess is evacuated by making an incision close to the border of the orbit, above 
or below the eyeball. 
5. The Nasal Region (Fig. 260). 
Pyramidalis nasi. 
Levator labii superioris alre^ue nasi. 
Dilatator naris posterior. 
Dilatator naris anterior. 
Compressor nasi. 
Compressor narium minor. 
The Pyramidalis Nasi is a small pyramidal slip placed over the nasal bone. 
Its origin is by tendinous fibres from the fascia covering the lower part of the nasal 
bone and upper part of the cartilage, where it blends with the Compressor nasi, 
and it is inserted into the skin over the lower part of the forehead between the 
two eyebrows, its fibres decussating with those of the Occipito-frontalis (see 
page 368). 
Relations.-By its upper surface, with the skin; by its under surface, with the 
frontal and nasal bones. 
The Levator Labii Superioris Alaeque Nasi is a thin triangular muscle placed 
by the side of the nose, and extending between the inner margin of the orbit and 
Depressor alte nasi. 376 
THE MUSCLES AND FASCIAE 
upper lip. It arises by a pointed extremity from the upper part of the nasal 
process of the superior maxillary bone, and, passing obliquely downward and 
outward, divides into two slips, one of which is inserted into the cartilage of the 
ala of the nose and the under surface of the skin over the ala; the other is pro- 
longed into the upper lip, becoming attached to the under surface of the skin 
and blended with the Orbicularis oris and Levator labii superioris proprius. 
Relations.-In front, with the integument, and with a small part of the Orbicu- 
laris palpebrarum above. 
The Dilatator Naris Posterior is a small muscle which is placed partly beneath 
the elevator of the nose and lip. It arises from the margin of the nasal notch of 
the superior maxilla and from the sesamoid cartilages, and is inserted into the 
skin near the margin of the nostril. 
The Dilatator Naris Anterior is a thin delicate fasciculus passing from the 
cartilage of the ala of the nose to the integument near its margin. This muscle is 
situated in front of the preceding. 
'rhe Compressor Nasi is a small, thin, triangular muscle arising by its apex 
from the superior maxillary bone, above and a little external to the incisive fossa; 
its fibres proceed upward and inward, expanding into a thin aponeurosis which 
is attached to the fibro-cartilage of the nose and is continuous on the bridge of 
the nose with that of the muscle of the opposite side and with the aponeurosis of 
the Pyramidalis nasi. His uses the term musculus nasalis to include the Com- 
pressor nasi (transverse portion of the nasal muscle), and the Dilatator naris 
posterior and the Dilatator naris anterior (alar portion of the nasal muscle). 
The Compressor Narium Minor is a small muscle attached by one end to the 
alar cartilage, and by the other to the integument at the end of the nose. 
The Depressor Alae Nasi (depressor septi} is a short radiated muscle arising 
from the incisive fossa of the superior maxilla; its fibres ascend to be inserted into 
the septum and back part of the ala of the nose. This muscle lies between the 
mucous membrane and muscular structure of the lip. 
Nerves.-All of the muscles of this group are supplied by the facial nerve. 
Actions.-The Pyramidalis nasi draws down the inner angle of the eyebrows 
and produces transverse wrinkles over the bridge of the nose. The Levator labii 
superioris akeque nasi draws upward the upper lip and ala of the nose; its most 
important action is upon the nose, which it dilates to a considerable extent. The 
action of this muscle produces a marked influence over the countenance, and it is 
the principal agent in the expression of contempt and disdain. The two Dilatatores 
nasi enlarge the aperture of the nose. Their action in ordinary breathing is to 
resist the tendency of the nostrils to close from atmospheric pressure, but in 
difficult breathing they may be noticed to be in violent action, as well as in some 
emotions, as anger. The Depressor alae nasi is a direct antagonist of the other 
muscles of the nose, drawing the ala of the nose downward, and thereby constrict- 
ing the aperture of the nares. The Compressor nasi depresses the cartilaginous 
part of the nose and compresses the alae together. 
Levator labii superioris. 
Levator anguli oris. 
6. The Superior Maxillary Region (Fig. 260). 
Zygomaticus major. 
Zygomaticus minor. 
By the term musculus quadratus labii superioris, His includes three muscles. 
The caput angulare is called in this book the Levator labii superioris akeque nasi. 
The caput infraorbitale is called the Levator labii superioris. The caput zygomati- 
cum is called the Zygomaticus minor. 
The Levator Labii Superioris (proprius} is a thin muscle of a quadrilateral 
form. It arises from the lower margin of the orbit immediately above the infra- THE MANDIBULAR REGION 
377 
orbital foramen, some of its fibres being attached to the superior maxilla, others 
to the malar bone; its fibres converge to be inserted into the muscular substance 
of the upper lip. 
Relations.-By its superficial surface above, with the lower segment of the 
Orbicularis palpebrarum; below, it is subcutaneous. By its deep surface it con- 
ceals the origin of the Compressor nasi and Levator anguli oris muscles, and the 
infraorbital vessels and nerve, as they escape from the infraorbital foramen. 
The Levator Anguli Oris (m. caninus) arises from the canine fossa immediately 
below the infraorbital foramen; its fibres incline downward and a little outward, to 
be inserted into the deep surface of the skin and into the subcutaneous tissue 
near the angle of the mouth and intermingles with the fibres of the Zygomaticus 
major, the Depressor anguli oris, and the Orbicularis. 
Relations.-By its superficial surface, with the Levator labii superioris and 
the infraorbital vessels and nerves; by its deep surface, with the superior maxilla, 
the Buccinator, and the mucous membrane. 
The Zygomaticus Major (m. zygomaticus) is a slender fasciculus which 
arises from the malar bone, in front of the zygomatic suture, and, descending 
obliquely downward and inward, is inserted into the deep surface of the skin 
and subcutaneous tissue at the outer portion of the upper lip and into the angle 
of the mouth, where it blends with the fibres of the Levator anguli oris, the 
Orbicularis oris, and the Depressor anguli oris. 
Relations.-By its superficial surface, with the subcutaneous adipose tissue; 
by its deep surface, with the Masseter and Buccinator muscles and the facial artery 
and vein. 
The Zygomaticus Minor, which is often absent, arises from the malar bone 
immediately behind the maxillary suture, and, passing downward and inward, is 
inserted into the deep surface of the skin and the adjacent muscles at the upper 
margin of the exposed vermilion surface of the lip midway between the middle 
line of the lip and the angle of the mouth. It is continuous with the Orbicularis 
oris at the outer margin of the Levator labii superioris. It lies in front of the 
preceding. 
Relations.-By its superficial surface, with the integument and the Orbicularis 
palpebrarum above; by its deep surface, with the Masseter, Buccinator, and 
Levator anguli oris, and the facial artery and vein. 
Nerves.-This group of muscles is supplied by the facial nerve. 
Actions.-The Levator labii superioris is the proper elevator of the upper lip, 
carrying it at the same time a little forward. It assists in forming the naso-labial 
ridge, which passes from the side of the nose to the upper lip and gives to the 
face an expression of sadness. The Levator anguli oris raises the angle of the 
mouth and draws it inward, and assists the Levator labii superioris in producing 
the naso-labial ridge. The Zygomaticus major draws the angle of the mouth 
backward and upward, as in laughing; whilst the Zygomaticus minor, being 
inserted into the outer part of the upper lip and not into the angle of the 
mouth, draws it backward, upward, and outward, and thus gives to the face 
an expression of sadness. 
7. The Mandibular Region (Fig. 260). 
Levator labii inferioris. Depressor labii inferioris. 
Depressor anguli oris. 
Dissection.-The muscles in this region may be dissected by making a vertical incision 
through the integument from the margin of the lower lip to the chin; a second incision should 
then be carried along the margin of the lower jaw as far as the angle, and the integument care- 
fully removed in the direction shown in Fig. 258. 378 
THE MUSCLES AND FASCIAE 
The Levator Labii Inferioris or Levator Menti (m. mentalis) is to be dissected 
by everting the lower lip and raising the mucous membrane. It is a small conical 
fasciculus placed on the side of the frsenum of the lower lip. It arises from the 
incisive fossa, external to the symphysis of the lower jaw; its fibres descend to 
be inserted into the integument of the chin. 
Relation.-On its inner surface, with the mucous membrane; in the median 
line, it is blended with the muscle of the opposite side; and on its outer side, with 
the Depressor labii inferioris. 
The Depressor Labii Inferioris or Quadratus Menti (m. quadratus labii 
inferioris) (Fig. 264) is a small quadrilateral muscle. It arises from the external 
oblique line of the lower jaw, between the symphysis and mental foramen, and 
passes obliquely upward and inward, to be inserted into the integument of the 
lower lip, its fibres blending with the Orbicularis oris and with those of its fellow 
of the opposite side. It is continuous with the fibres of the Platysma at its origin. 
This muscle contains much yellow fat intermingled with its fibres. 
Relations.-By its superficial surface, with part of the Depressor anguli oris 
and with the integument, to which it is closely connected; by its deep surface, 
with the mental vessels and nerves, the mucous membrane of the lower lip, the 
labial glands, and the Levator menti, with which it is intimately united. 
The Depressor Anguli Oris or Triangularis Menti (m. triangularis) (Fig. 260) 
is triangular in shape, arising, by its broad base, from the external oblique line of 
the lower jaw, from whence its fibres pass upward, to be inserted, by a narrow 
fasciculus, into the angle of the mouth. It is continuous with the Platysma at 
its origin and with the Orbicularis oris and Risorius at its insertion, and some of 
its fibres are directly continuous with those of the Levator anguli oris. Muscular 
fibres connecting the two muscles below the chin are occasionally met with; they 
constitute the Musculus transversus menti of His and Waldeyer. 
Relations.-By its superficial surface, with the integument; by its deep surface, 
with the Depressor labii inferioris and Buccinator. 
Nerves.-This group of muscles is supplied by the facial nerve. 
Actions.-The Levator labii inferioris raises the lower lip and protrudes it 
forward, and at the same time wrinkles the integument of the chin, expressing 
doubt or disdain. The Depressor labii inferioris draws the lower lip directly 
downward and a little outward, as in the expression of irony. The Depressor 
anguli oris depresses the angle of the mouth, being the antagonist to the Levator 
anguli oris and Zygomaticus major; acting with these muscles, it will draw the 
angle of the mouth directly backward. 
8. The Intermaxillary Region. 
Orbicularis oris. Buccinator. Risori us. 
Dissection.-The dissection of these muscles may be considerably facilitated by filling the 
cavity of the mouth with tow, so as to distend the cheeks and lips; the mouth should then be 
closed by a few stitches and the integument carefully removed from the surface. 
The Orbicularis oris (Figs. 260 and 264) is not a sphincter muscle, like the Orbic- 
ularis palpebrarum, but consists of numerous strata of muscular fibres, having dif- 
ferent directions, which surround the orifice of the mouth. These fibres are par- 
tially derived from the other facial muscles which are inserted into the lips, and are 
partly fibres proper to the lips themselves. Of the former, a considerable number 
are derived from the Buccinator and form the deeper stratum of the Orbicularis. 
Some of them-namely, those near the middle of the muscle-decussate at the 
angle of the mouth, those arising from the upper jaw passing to the lower lip, and 
those from the lower jaw to the upper lip. Other fibres of the muscle, situated at THE INTERMAXILLARY REGION 
379 
its upper and lower part, pass across the lips from side to side without decussation. 
Superficial to this stratum is a second, formed by the Levator and Depressor 
anguli oris, which cross each other at the angle of the mouth, those from the 
Depressor passing to the upper lip, and those from the Levator to the lower lip, 
along which they run to be inserted into the skin near the median line. In addi- 
Fig. 264.-Temporal and deep muscles about the mouth. (Testut.) 
tion to these there are fibres from the other muscles inserted into the lips-the 
Levator labii superioris, the Levator labii superioris abeque nasi, the Zygomatici, 
and the Depressor labii inferioris; these intermingle with the transverse fibres 
above described, and have principally an oblique direction. The proper fibres of 
the lips are oblique, and pass from the under surface of the skin to the mucous 
membrane through the thickness of the lip. And in addition to these are fibres 380 
THE MUSCLES AND FASCIAE 
by which the muscle is connected directly with the maxillary bones and the 
septum of the nose. These consist, in the upper lip, of four bands, two of 
which (m. incisivus superior) arise from the alveolar border of the superior 
maxilla, opposite the lateral incisor tooth, and, arching outward on each side, 
are continuous at the angles of the mouth with the other muscles inserted into 
this part. The two remaining muscular slips, called the Nasolabialis, connect 
the upper lip to the back of the septum of the nose: as they descend from the 
septum an interval is left between them. It is this interval which forms the depres- 
sion seen on the surface of the skin beneath the septum of the nose, which is 
called the philtrum. The additional fibres for the lower segment (m. incisivus 
inferior) arise from the inferior maxilla, externally to the Levator labii inferioris, 
and arch outward to the angles of the mouth, to join the Buccinator and the other 
muscles attached to this part. 
Relations.-By its superficial surface, with the integument, to which it is closely 
connected; by its deep surface, with the buccal mucous membrane, the labial 
glands, and coronary vessels; by its outer circumference it is blended with the 
numerous muscles which converge to the mouth from various parts of the face. 
Its inner circumference is free, and covered by the mucous membrane. 
The Buccinator (Fig. 264) is a broad, thin muscle, quadrilateral in form, 
which occupies the interval between the jaws at the side of the face. It arises 
from the outer surface of the alveolar processes of the upper and lower jaws, 
corresponding to the three molar teeth, and, behind, from the anterior border of 
the pterygo-maxillary ligament. The fibres converge toward the angle of the 
mouth, where the central fibres intersect each other, those from below being 
continuous with the upper segment of the Orbicularis oris, and those from above 
with the inferior segment; the highest and lowest fibres continue forward uninter- 
ruptedly into the corresponding segment of the lip, without decussation. 
Relations.-By its superficial surface, behind, with a large mass of fat, the sucking 
or suctorial pad (corpus adiposum buccoe), which separates it from the ramus of the 
lower jaw, the Masseter, and a small portion of the Temporal muscle. The suck- 
ing pad is much more developed relatively in children than in adults. It assists 
sucking by aiding the cheek to resist atmospheric pressure. The buccinator 
muscle is in relation, anteriorly, with the Zygomatici, Risorius, Levator anguli 
oris, Depressor anguli oris, and Stenson's duct, which pierces it opposite the 
second molar tooth of the upper jaw; the facial artery and vein cross it from below 
upward; it is also crossed by the branches of the facial and buccal nerves; by 
its internal surface, with the buccal glands and mucous membrane of the mouth. 
The Pterygo-maxillary or Pterygo-mandibular Ligament {raphe pterygomandib- 
ularis) separates the Buccinator muscle from the Superior constrictor of the 
pharynx. It is a tendinous thickening of the bucco-pharyngeal fascia, attached by 
one extremity to the apex of the internal pterygoid plate, and by the other to the 
posterior extremity of the internal oblique line of the lower jaw. Its inner surface 
corresponds to the cavity of the mouth, and is lined by mucous membrane. Its 
outer surface is separated from the ramus of the jaw by a quantity of adipose 
tissue. Its posterior border gives attachment to the Superior constrictor of the 
pharynx; its anterior border, to the fibres of the Buccinator. 
The Bucco-pharyngeal fascia (fascia buccopharyngea) is a thin fascia covering 
the external surface of the Buccinator muscle. It is gradually lost in front of the 
angle of the mouth. Posteriorly it is continued over the external surface of the 
throat muscles. Its thickened cord-like portion is the stylo-mandibular ligament. 
The Risorius or Santorini's Muscle (m. risorius) (Fig. 260) consists of a 
narrow bundle of fibres which arises in the fascia over the Masseter muscle, 
and, passing horizontally forward, is inserted with the Depressor anguli oris into 
the subcutaneous and muscular tissue at the angle of the mouth. It is placed THE TEMPORO-MANDIBULAR REGION 
381 
superficial to the Platysma, and is broadest at its outer extremity. This muscle 
varies much in its size and form. 
Nerves.-The muscles in this group are all supplied by the facial nerve. The 
buccal branch of the inferior maxillary nerve pierces the Buccinator muscle, and 
by some anatomists is regarded as partly supplying this muscle. Probably it 
merely pierces it on its way to the mucous membrane of the cheek. 
Actions.-The Orbicularis oris in its ordinary action produces the direct closure 
of the lips; by its deep fibres, assisted by the oblique ones, it closely applies the 
lips to the alveolar arch. The superficial part, consisting principally of the decus- 
sating fibres, brings the lips together and also protrudes them forward. The Buc- 
cinators contract and compress the cheeks, so that, during the process of mastica- 
tion, the food is kept under the immediate pressure of the teeth. When the cheeks 
have been previously distended with air, the Buccinator muscles expel it from 
between the lips, as in blowing a trumpet. Hence the name (buccina, a trumpet). 
The Risorius retracts the angles of the mouth, and produces the unpleasant 
expression which is sometimes seen in tetanus, and is known as risus sardonicus, the 
sardonic laugh. 
9. The Temporo-mandibular Region. 
Masseter. Temporal. 
The Masseteric Fascia (fascia par otideomasset erica) covers the outer and inner 
surfaces of the parotid gland as a thick membrane, called the parotid fascia. It 
passes forward, and becomes thinner to cover the Masseter muscle, to which it 
is firmly connected. It is derived from the deep cervical fascia. Above, this 
fascia is attached to the lower border of the zygoma. It is lost in front below 
the Risorius and Platysma. 
The Masseter Muscle is exposed by the removal of this fascia (Fig. 260); it is a 
short, thick muscle, somewhat quadrilateral in form, consisting of two portions, 
superficial and deep. The superficial portion, the larger, arises by a thick, tendinous 
aponeurosis from the malar process of the superior maxilla, and from the anterior 
two-thirds of the lower border of the zygomatic arch: its fibres pass downward 
and backward, to be inserted into the angle and lower half of the outer surface 
of the ramus of the jaw. The deep portion is much smaller and more muscular 
in texture; it arises from the posterior third of the lower border and the whole of 
the inner surface of the zygomatic arch; its fibres pass downward and forward, 
to be inserted into the upper half of the ramus and outer surface of the coronoid 
process of the jaw. The deep portion of the muscle is partly concealed, in front 
by the superficial portion; behind, it is covered by the parotid gland. The fibres 
of the two portions are united at their insertion. 
Relations.-By its superficial surface, with the Zygomatici, the parotid gland 
and Socia parotidis, and Stenson's duct; the branches of the facial nerve and 
the transverse facial vessels, which cross it; the masseteric fascia; the Risorius, 
Platysma myoides, and the integument; by its deep surface, with the Temporal 
muscle at its insertion, the ramus of the jaw, the Buccinator and the long 
buccal nerve, from which it is separated by a mass of fat (suctorial or sucking pad). 
The masseteric nerve and artery enter in on its under surface. Its posterior margin 
is overlapped by the parotid gland. Its anterior margin projects over the Bucci- 
nator muscle, and the facial vein lies on it below. 
Temporal Fascia (fascia temporalis).-The temporal fascia is seen, at this stage 
of a dissection, covering in the Temporal muscle. It is a strong, fibrous invest- 
ment, covered, on its outer surface, by the Attrahens and Attollens auriculam mus- 
cles, the aponeurosis of the Occipito-frontalis, and by part of the Orbicularis palpe- 
brarum. The temporal vessels and the auriculo-temporal nerve cross it from below 
upward. Above, it is a single layer, attached to the entire extent of the upper tern- THE MUSCLES AND EASCILE 
382 
poral ridge; but below, where it is attached to the zygoma, it consists of two layers, 
one of which is inserted into the outer, and the other into the inner, border of the 
zygomatic arch. A small quantity of fat, the orbital branch of the temporal artery, 
and a filament from the orbital, or temporo-malar, branch of the superior maxillary 
nerve are contained between these two layers. It affords attachment by its inner 
surface to the superficial fibres of the Temporal muscle. 
Dissection.-In order to expose the Temporal muscle, remove the temporal fascia, which 
may be effected by separating it at its attachment along the upper border of the zygoma, and 
dissecting it upward from the surface of the muscle. The zygomatic arch should then 
be divided in front at its junction with the malar bone, and behind near the external auditory 
meatus, and drawn downward with the Masseter, which should be detached from its inser- 
tion into the ramus and angle of the jaw. The whole extent of the Temporal muscle is then 
exposed. 
The Temporal Muscle (m. temporalis) (Figs. 264 and 265) is a broad, radiating 
muscle situated at the side of the head and occupying the entire extent of the tem- 
poral fossa. It arises from the whole of the temporal fossa except that portion of it 
that is formed by the malar bone. Its attachment extends from the external angular 
process of the frontal in front to the mastoid portion of the temporal behind, and 
from the curved line on the frontal and parietal bones above to the pterygoid ridge 
on the great wing of the sphenoid below. It is also attached to the inner surface of 
the temporal fascia. Its fibres converge as they descend, and terminate in an apon- 
eurosis, the fibres of which, radiated at its commencement, converge into a thick 
and flat tendon, which is inserted into the inner surface, apex, and anterior border 
of the coronoid process of the jaw, nearly as far forward as the last molar tooth. 
Relations.-By its superficial surjace, with the integument, the Attrahens and 
Attollens auriculam muscles, the temporal vessels and nerves, the aponeurosis of 
the Occipito-frontalis, the temporal fascia, the zygoma, and Masseter; by its 
deep surjace, with the temporal fossa, the External pterygoid and part of the 
Buccinator muscles, the internal maxillary artery and its deep temporal branches, 
and the deep temporal nerves. Behind the tendon are the masseteric vessels and 
nerve, and in front of it the buccal vessels and nerve. Its anterior border is sepa- 
rated from the malar bone by a mass of fat. 
Nerves.-Both muscles are supplied by the inferior maxillary nerve. 
Fig. 265.-The Temporal muscle, the zygoma and Masseter having been removed. THE PTERYGO-MANDIBULAR REGION 
383 
10. The Pterygo-mandibular Region (Figs. 266, 267). 
External pterygoid. Internal pterygoid. 
Dissection.-The Temporal muscle having been examined, saw through the base of the 
coronoid process, and draw it upward, together with the Temporal muscle, which should be 
detached from the surface of the temporal fossa. Divide the ramus of the jaw just below the 
condyle, and also, by a transverse incision extending across the middle, just above the dental 
foramen; remove the fragment, and the Pterygoid muscles will be exposed. 
The External Pterygoid Muscle (m. pterygoideus externus) is a short, thick 
muscle, somewhat conical in form, which extends almost horizontally between the 
zygomatic fossa and the condyle of the jaw. It arises by two heads, separated 
by a slight interval: the upper head arises from the inferior surface of the greater 
wing of the sphenoid and from the pterygoid ridge, which separates the zygo- 
matic from the temporal fossa; the lower head from the outer surface of the external 
pterygoid plate. Its fibres pass horizontally backward and outward, to be inserted 
into a depression in front of the neck of the condyle of the lower jaw and into the 
corresponding part of the interarticular fibro-cartilage. 
Fig. 266.-The Pterygoid muscles, the zygomatic arch, and a portion of the ramus of the jaw having 
been removed. 
Relations.-By its external surface, with the ramus of the lower jaw, the internal 
maxillary artery, which crosses it,1 the tendon of the Temporal muscle, and the 
Masseter; by its internal surface it rests against the upper part of the Internal 
pterygoid muscle, the internal lateral ligament, the middle meningeal artery, and 
inferior maxillary nerve; by its upper border it is in relation with the temporal and 
masseteric branches of the inferior maxillary nerve; by its lower border it is in 
relation with the inferior dental and gustatory nerves. Through the interval 
between the two portions of the muscle, the buccal nerve emerges and the internal 
maxillary artery passes, when the trunk of this vessel lies on the muscle. 
The Internal Pterygoid Muscle (m. pterygoideus internus) is a thick, quadri- 
lateral muscle, and resembles the Masseter in form. It arises from the pterygoid 
fossa, being attached to the inner surface of the external pterygoid plate and to 
1 This is the usual relation, but in many cases the artery will be found below the muscle. THE MUSCLES AND EASCEE 
384 
the grooved surface of the tuberosity of the palate bone, and by a second slip from 
the outer surface of the tuberosities of the palate and superior maxillary bones; 
its fibres pass downward, outward, and backward, to be inserted, by a strong, ten- 
dinous lamina, into the lower and back part of the inner side of the ramus and 
angle of the lower jaw, as high as the dental foramen. 
Relations.-By its external surface, with the ramus of the lower jaw, from 
which it is separated, at its upper part, by the External pterygoid muscle, the 
internal lateral ligament, the internal maxillary artery, the dental vessels and 
nerves, and the lingual nerve, and a process of the parotid gland. By its internal 
surface, with the Tensor palati, being separated from the Superior constrictor of 
the pharynx by a cellular interval. 
Fig. 267.-Pterygoid muscles, viewed from behind, the back portion of the skull having been removed. 
(Testut.) 
Nerves.-These muscles are supplied by the inferior maxillary nerve. 
Actions.-The Temporal and Masseter and Internal pterygoid raise the lower 
jaw against the upper with great force. The superficial portion of the Masseter 
assists the External pterygoid in drawing the lower jaw forward upon the upper, 
the jaw being drawn back again by the deep fibres of the Masseter and posterior 
fibres of the Temporal. The External pterygoid muscles are the direct agents in 
the trituration of the food, drawing the lower jaw directly forward, so as to make 
the lower teeth project beyond the upper. If the muscle of one side acts, the 
corresponding side of the jaw is drawn forward, and, the other condyle remaining 
fixed, the symphysis deviates to the opposite side. The alternation of these move- 
ments on the two sides produces trituration. MUSCLES AND FASCIAE OF THE NECK 
385 
Surface Form.-The outline of the muscles of the head and face cannot be traced on the 
surface of the body, except in the case of two of the masticatory muscles. Those of the head 
are thin, so that the outline of the bone is perceptible beneath them. Those in the face are 
small, covered by soft skin, and often by a considerable layer of fat, so that their outline is con- 
cealed, but they serve to round off and smooth prominent borders and to fill up what would be 
otherwise unsightly angular depressions. Thus, the Orbicularis palpebrarum rounds off the 
prominent margin of the orbit, and the Pyramidalis nasi fills in the sharp depression beneath 
the glabella, and thus softens and tones down the abrupt depression which is seen on the 
unclothed bone. In like manner, the labial muscles, converging to the lips and assisted by the 
superimposed fat, fill in the sunken hollow of the lower part of the face. Although the muscles 
of the face are usually described as arising from the bones and inserted into the nose, lips, and 
corners of the mouth, they have fibres inserted into the skin of the face along their whole 
extent, so that almost every point of the skin of the face has its muscular fibre to move it; 
hence it is that when in action the facial muscles produce alterations in the skin-surface, 
giving rise to the formation of various folds or wrinkles, or otherwise altering the relative 
position of the parts, so as to produce the varied expressions with which the face is endowed; 
hence these muscles are termed the muscles of expression. The only two muscles in this 
region which greatly influence surface form are the Masseter and the Temporal. The Masseter 
is a quadrilateral muscle, which imparts fulness to the hinder part of the cheek. When the 
muscle is firmly contracted, as when the teeth are clenched, its outline is plainly visible; 
the anterior border forms a prominent vertical ridge, behind which is a considerable fulness, 
especially marked at the lower part of the muscle; this fulness is entirely lost when the 
mouth is opened and the muscle no longer in a state of contraction. The Temporal muscle 
is fan-shaped, and fills the Temporal fossa, substituting for it a somewhat convex form, the 
anterior part of which, on account of the absence of hair over the temple, is more marked than 
the posterior, and stands out in strong relief when the muscle is in a state of contraction. 
MUSCLES AND FASCIA OF THE NECK 
The muscles of the neck may be arranged into groups corresponding with the 
region in which they are situated. 
These groups are nine in number: 
1. Superficial Cervical Region. 
2. Depressors of the Os Hyoideum 
and Larynx. 
3. Elevators of the Os Hyoideum 
and Larynx. 
4. Muscles of the Tongue. 
5. Muscles of the Pharynx. 
6. Muscles of the Soft Palate. 
7. Muscles of the Anterior Ver- 
tebral Region. 
8. Muscles of the Lateral Ver- 
tebral Region. 
9. Muscles of the Larynx. 
The muscles contained in each of these groups are the following: 
1. Superficial Region. 
Platysma myoides. 
Sterno-cleido-mastoid. 
Infra-hyoid Region. 
2. Depressors of Os hyoideum and 
Larynx. 
Sterno-hyoid. 
Sterno-thyroid. 
Thyro-hyoid. 
Omo-hyoid. 
Supra-hyoid Region. 
3. Elevators of Os hyoideum and Larynx. 
Digastric. 
Stylo-hyoid. 
Mylo-hyoid. 
Genio-hyoid. 
Lingual Region. 
4. Muscles of the Tongue. 
Genio-hyo-glossus. 
Hyo-glossus. 
Chondro-glossus. 
Stylo-glossus. 
Palato-glossus. 
5. Muscles of the Pharynx. 
Inferior constrictor. 
Middle constrictor. 
Superior constrictor. 
Stylo-pharyngeus. 
Palato-pharyngeus. THE MUSCLES AND EASCLE 
386 
6. Muscles of the Soft Palate. 
Levator palati. 
Tensor palati. 
Azygos uvulae. 
Palato-glossus. 
Palato-pharyngeus. 
Salpingo-pharyngeus. 
7. Musclesof theAnteriorVertebral Region. 
Rectus capitis anticus major. 
Rectus capitis anticus minor. 
Rectus capitis lateralis. 
Longus colli. 
8. Muscles of the Lateral Vertebral 
Region. 
Scalenus anticus. 
Scalenus medius. 
Scalenus posticus. 
9. Muscles of the Larynx. 
Included in description of the 
Larynx. 
1. The Superficial Cervical Region. 
Dissection.-A block having been placed at the back of the neck, and the face turned to 
the side opposite that to be dissected, so as to place the parts upon the stretch, make two trans- 
verse incisions: one from the chin, along the margin of the lower jaw, to the mastoid process, 
and the other along the upper border of the clavicle. Connect these by an oblique incision 
made in the course of the Sterno-mastoid muscle, from the mastoid process to the sternum; the 
two flaps of integument having been removed in the direction shown in Fig. 257, the superficial 
fascia will be exposed. 
Platysma myoides. Sterno-cleido-mastoid. 
Superficial Cervical Fascia.-The superficial cervical fascia is a thin, apon- 
eurotic lamina which is hardly demonstrable as a separate membrane. Beneath 
it is found the Platysma myoides muscle. 
The Platysma Myoides (m. platysma) (Fig. 260) is a broad, thin plane of mus- 
cular fibres placed immediately beneath the superficial fascia on each side of the 
neck. It arises by thin, fibrous bands from the fascia covering the upper part of the 
Pectoral and Deltoid muscles; its fibres pass over the clavicle and proceed obliquely 
upward and inward along the side of the neck. The anterior fibres interlace, 
below and behind the symphysis menti, with the fibres of the muscle of the oppo- 
site side; the posterior fibres pass over the lower jaw, some of them being attached 
to the bone below the external oblique line, others passing on to be inserted into 
the skin and subcutaneous tissue of the lower part of the face, many of these fibres 
blending with the muscles about the angle and lower part of the mouth. Some- 
times fibres can be traced to the Zygomatic muscles or to the margin of the 
Orbicularis oris. Beneath the Platysma the external jugular vein may be seen 
descending in a line from the angle of the jaw to the middle of the clavicle. 
Relations.-By its external surface, with the integument, to which it is united 
more closely below than above; by its internal surface, with the Pectoralis major 
and Deltoid, and with the clavicle. In the neck, with the external and anterior 
jugular veins, the deep cervical fascia, the superficial branches of the cervical 
plexus, the Sterno-mastoid, Sterno-hyoid, Omo-hyoid, and Digastric muscles; 
behind the Sterno-mastoid muscle it covers in the posterior triangle of the neck. 
On the face it is in relation with the parotid gland, the facial artery and vein, 
and the Masseter and Buccinator muscles. 
Nerves.-The lower division of the facial nerve chiefly innervates this muscle, 
and superficial branches from the cervical plexus also reach it. 
Action.-The Platysma myoides produces a slight wrinkling of the surface of 
the skin of the neck, in an oblique direction, when the entire muscle is brought 
into action. Its anterior portion, the thickest part of the muscle, depresses the 
lower jaw; it also serves to draw down the lower lip and angle of the mouth on 
each side, being one of the chief agents in the expression of melancholy. In the 
pressure upon the blood-vessels of the neck induced by strong inspiratory effort. THE SUPERFICIAL CERVICAL REGION 
387 
this muscle draws away the skin and fascia, and by so doing, greatly diminishes 
the pressure on the veins. 
Deep Cervical Fascia fascia colli) (Fig. 268).-The deep cervical fascia 
lies under cover of the Platysma myoides muscle and constitutes a complete 
investment for the neck. It also forms a sheath for the carotid vessels, and, in 
addition, is prolonged deeply in the shape of certain processes or lamellae, which 
come into close relation with the structures situated in front of the vertebral column. 
SPACE BETWEEN THE 
TWO LAYERS OF FASCIA 
STERNOTHYROID 
DEEP FASCIA OF NECK 
STERNOHYOID 
OMOHYOID 
COMMON CAROTID 
ARTERY 
DESCENDENS HYPO- 
GLOSSI NERVE 
TRACHEA 
PNEUMOGASTRIC 
NERVE 
OESOPHAGUS- 
.LYMPHATIC 
GLANDS 
SYMPATHETIC 
NERVE 
PREVERTEBRAL 
FASCIA 
PHRENIC 
NERVE 
. INTERNAL 
JUGULAR 
VEIN 
BRACHIAL 
'PLEXUS 
-PLATYSMA 
SUPERFICIAL 
FASCIA OF 
N ECK 
Fig. 268.-Transverse section through the neck at the level of the seventh cervical vertebra. (Spalteholz.) 
The investing portion of the fascia is attached, behind, to the ligamentum 
nuchae and to the spine of the seventh cervical vertebra. Along this line it splits 
to enclose the Trapezius muscle, at the anterior border of which the two enclosing 
lamellae unite and form a strong membrane, which extends forward so as to roof 
in the posterior triangle of the neck. Along the hinder edge of the Sterno-mastoid 
the membrane divides to enclose this muscle, at the anterior edge of which it once 
more forms a single lamellae, which roofs in the anterior triangle of the neck, 
and, reaching forward to the middle line, is continuous with the corresponding 
part from the opposite side of the neck. In the middle line of the neck it is attached 
to the symphysis menti and to the body of the hyoid bone. 388 
THE MUSCLES AND FASCLE 
Above, the fascia is attached to the superior curved line of the occiput, to the 
mastoid process of the temporal, and to the whole length of the body of the jaw. 
Opposite the angle of the jaw the fascia is very strong, and binds the anterior 
edge of the Sterno-mastoid firmly to that bone. Between the jaw and the mastoid 
process it ensheaths the parotid gland-the layer which covers the gland extending 
upward under the name of the parotid fascia to be fixed to the zygomatic arch. 
The parotid fascia is prolonged forward to cover the masseter muscle, the masse- 
teric jascia. From the layer which passes under the parotid a strong band, 
the stylo-mandibular ligament, reaches from the styloid process to the angle of 
the jaw. The parotid and masseteric fascia? constitute the fascia parotideo- 
masseterica. 
Below, the cervical fascia is attached to the acromion process, the clavicle, and 
to the manubrium sterni. Some little distance above the last-named point, how- 
ever, it splits into two layers, superficial and deep. The former is attached to 
the anterior border of the manubrium, the latter to its posterior border and to 
the interclavicular ligament. Between these two layers is a slit-like interval, the 
suprasternal space or space of Burns (spatium suprasternale}. It contains a small 
quantity of areolar tissue, and sometimes a lymphatic gland; the lower portions 
of the anterior jugular veins and their transverse connecting branch; and also 
the sternal heads of the Sterno-mastoid muscles. 
The fascia which lines the deep aspect of the Sterno-mastoid gives off certain 
important processes, viz.: (1) A process to envelop the tendon of the Omo-hyoid, 
and bind it down to the sternum and first costal cartilage. (2) A strong sheath, 
the carotid sheath, for the large vessels of the neck, enclosed within which are the 
carotid artery, internal jugular vein, the vagus, and descendens hypoglossi nerves. 
(3) The prevertebral fascia (jascia pravertebralis), which extends inward behind 
the carotid vessels, where it assists in forming their sheath, and passes in front 
of the prevertebral muscles. It thus forms the posterior limit of a fibrous com- 
partment which contains the larynx and trachea, the thyroid gland, and the 
pharynx and oesophagus. The prevertebral fascia is fixed above to the base of 
the skull, while below it is continued into the thorax in front of the Longus colli 
muscles. Parallel to the carotid vessels and along their inner aspect it gives off 
a thin lamina, the bucco-pharyngeal fascia (jascia buccopharynged), which closely 
invests the constrictor muscles of the pharynx, and is continued forward from 
the Superior constrictor on to the Buccinator. It is attached to the prever- 
tebral layer by loose connective tissue only, and thus an easily distended space, 
the retro-pharyngeal space (spatium retropharynged), is found between them. This 
space is limited above by the base of the skull, while below it extends behind the 
oesophagus into the thorax, where it is continued into the posterior mediastinum. 
The prevertebral fascia is prolonged downward and outward behind the carotid 
vessels and in front of the Scaleni muscles, and forms a sheath for the brachial 
plexus of nerves and for the subclavian vessels in the posterior triangle of the neck, 
and, continuing under the clavicle as the axillary sheath, is attached to the deep 
surface of the costo-coracoid membrane. Immediately above the clavicle an 
areolar space exists between the investing layer and the sheath of the subclavian 
vessels, and in it are found the lower part of the external jugular vein, the descend- 
ing clavicular nerves, the suprascapular and transversalis colli vessels, and the 
posterior belly of the Omo-hyoid muscle. This space extends downward behind 
the clavicle, and is limited below by the fusion of the costo-coracoid membrane 
with the anterior wall of the axillary sheath. (4) The pre-tracheal fascia, which 
extends inward in front of the carotid vessels, and assists in forming the carotid 
sheath. It is further continued behind the Depressor muscles of the hyoid bone, 
and, after enveloping the thyroid body, is prolonged in front of the trachea to 
meet the corresponding layer of the opposite side. Above, it is fixed to the hyoid THE SUPERFICIAL CERVICAL REGION. 
389 
bone, while below it is carried downward in front of the trachea and large vessels 
at the root of the neck, and ultimately blends with the fibrous pericardium. 
Surgical Anatomy.-The cervical fascia is of considerable importance from a surgical 
point of view. As will be seen from the foregoing description, it may be divided into three 
layers: (1) A superficial layer; (2) a layer passing in front of the trachea, and forming with 
the superficial layer a sheath for the depressors of the hyoid bone; (3) a prevertebral layer 
passing in front of the bodies of the cervical vertebrae, and forming with the second layer a 
space in which are contained the trachea, oesophagus, etc. The superficial layer forms a com- 
plete investment for the neck. It is attached behind to the ligamentum nuchse and the spine 
of the seventh cervical vertebra; above it is attached to the external occipital protuberance, to 
the superior curved line of the occiput, to the mastoid process, to the zygoma and the lower 
jaw; below it is attached to the manubrium sterni, the clavicle, the acromion process, and 
the spine of the scapula; in front it blends with the fascia of the opposite side. This layer 
opposes the extension of abscesses or new-growths toward the surface, and pus forming beneath 
it has a tendency to extend laterally. If pus is in the posterior triangle, it might extend 
backward under the Trapezius, forward under the Sterno-mastoid, or downward under the 
clavicle for some distance, until stopped by the junction of the cervical fascia to the Costo- 
coracoid membrane. If the pus is contained in the anterior triangle, it might find its way into 
the anterior mediastinum, being situated in front of the layer of fascia which passes down into 
the thorax to become continuous with the pericardium; but owing to the lesser density and 
thickness of the fascia in this situation it more frequently finds its way through it and points 
above the sternum. The second layer of fascia is connected above with the hyoid bone. It 
passes down beneath the depressors and in front of the thyroid body and trachea to become 
continuous with the fibrous layer of the pericardium. Laterally it invests the great vessels of 
the neck and is connected with the superficial layer beneath the Sterno-mastoid. Pus forming 
beneath this layer would in all probability find its way into the posterior mediastinum. The 
third layer (the prevertebral fascia) is connected above to the base of the skull. Pus forming 
beneath this layer, in cases, for instance, of caries of the bodies of the cervical vertebrae, might 
extend toward the posterior and lateral part of the neck and point in this situation, or might 
perforate this layer of fascia and the pharyngeal fascia and point into the pharynx (retro- 
pharyngeal abscess'). 
In cases of cut throat the cervical fascia is of considerable importance. When the wound 
involves only the superficial layer the injury is usually trivial, the only special danger being 
injury to the external jugular vein, and the only special complication being diffuse cellulitis. 
But where the second of the two layers has been opened up, important structures may have 
been injured, which may lead to serious results. 
It may be worth while mentioning that in Burns's space is contained the sternal head of 
origin of the Sterno-mastoid muscle, so that this space is opened in division of this tendon. 
The anterior jugular vein is also contained in the same space. 
The Sterno-mastoid or Sterno-cleido-mastoid (m. sternocleidomastoideus) 
(Fig. 269) is a large, thick muscle, which passes obliquely across the side of the 
neck, being enclosed between two layers of the deep cervical fascia. It is thick 
and narrow at its central part, but is broader and thinner at each extremity. It 
arises, by two heads, from the sternum and clavicle. The sternal portion is a 
rounded fasciculus, tendinous in front, fleshy behind, which arises from the 
upper and anterior part of the first piece of the sternum, and is directed 
upward, outward, and backward. The clavicular portion arises from the inner 
third of the superior border and anterior surface of the clavicle, being com- 
posed of fleshy and aponeurotic fibres; it is directed almost vertically upward. 
These two portions are separated from one another, at their origin, by a triangular 
cellular interval, but become gradually blended, below the middle of the neck, 
into a thick, rounded muscle, which is inserted, by a strong tendon, into the outer 
surface of the mastoid process of the temporal bone, from its apex to its superior 
border, and by a thin aponeurosis into the outer half of the superior curved line of 
the occipital bone. The Sterno-mastoid varies much in its extent of attachment 
to the clavicle: in one case the clavicular may be as narrow as the sternal portion; 
in another, the former may be as much as three inches in breadth. When the 
clavicular origin is broad, it is occasionally subdivided into numerous slips separ- 
ated by narrow intervals. More rarely, the corresponding margins of the Sterno- 
mastoid and Trapezius have been found in contact. In the application of a ligature 390 
THE MUSCLES AND FASCIAE 
to the third part of the subclavian artery it will be necessary, where the Sterno- 
mastoid and 'Trapezius come close together, to divide a portion of one or of both. 
This muscle divides the quadrilateral space at the side of the neck into two 
triangles, an anterior and a posterior. The boundaries of the anterior triangle 
are, in front, the median line of the neck; above, the lower border of the body of 
the jaw, and an imaginary line drawn from the angle of the jaw to the mastoid 
process; behind, the anterior border of the Sterno-mastoid muscle. The apex of 
the triangle is at the upper border of the sternum. The boundaries of the posterior 
triangle are, in front, the posterior border of the Sterno-mastoid; below, the middle 
third of the clavicle; behind, the anterior margin of the Trapezius.1 The apex corre- 
sponds with the meeting of the Sterno-mastoid and Trapezius on the occipital bone. 
Fig. 269.-Muscles of the neck and boundaries of the triangles. 
Relations.-By its superficial surface, with the integument and Platysma, 
from which it is separated by the external jugular vein, the superficial branches 
of the cervical plexus, and the anterior layer of the deep cervical fascia. By its 
deep surface it is in relation with the Sterno-clavicular articulation; a process of 
the deep cervical fascia; the Sterno-hyoid, Sterno-thyroid, Omo-hyoid, posterior 
belly of the Digastric, Levator anguli scapulae, Splenius and Scaleni muscles; 
common carotid artery, internal and anterior jugular veins, commencement of the 
internal and external carotid arteries, the occipital, subclavian, transversalis colli, 
and suprascapular arteries and veins; the phrenic, pneumogastric, hypoglossal, 
descendens and communicans hypoglossi nerves; the spinal accessory nerve, which 
pierces its upper third; the cervical plexus, parts of the thyroid and parotid glands, 
and deep lymphatic glands. 
Nerves.-The Sterno-cleido-mastoid is supplied by the spinal accessory nerve 
and deep branches of the cervical plexus. 
1 The anatomy of these triangles will be more exactly described with that of the vessels of the neck. THE INFRA-HYOID REGION 
391 
Actions.-When only one Sterno-mastoid muscle acts, it draws the head toward 
the shoulder of the same side, assisted by the Splenitis and the Obliquus capitis 
inferior of the opposite side. At the same time it rotates the head so as to carry 
the face toward the opposite side. When the two muscles act together they 
Hex the head upon the neck. If the head is fixed, the two muscles assist in 
elevating the thorax in forced inspiration. 
Surface Form.-The anterior edge of the muscle forms a very prominent ridge beneath the 
skin, which it is important to notice, as it forms a guide to the surgeon in making the necessary 
incisions for ligature of the common carotid artery and for oesophagotomy. 
Surgical Anatomy.-The relations of the sternal and clavicular parts of the Sterno-mastoid 
should be carefully examined, as the surgeon is sometimes required to divide one or both portions 
of the muscle in wry-neck (torticollis). One variety of this distortion is produced by spasmodic 
contraction or rigidity of the Sterno-mastoid; the head being carried down toward the shoulder 
of the same side, and the face turned to the opposite side and fixed in that position. When there 
is permanent shortening, subcutaneous division of the muscle is resorted to by some surgeons. 
This is performed by introducing a tenotomy knife beneath it, close to its origin, and dividing 
it from behind forward whilst the muscle is put well upon the stretch. There is seldom any 
difficulty in dividing the sternal portion by making a puncture on the inner side of the tendon, 
and then pushing a blunt tenotome behind it, and cutting forward. In dividing the clavicular 
portion care must be taken to avoid wounding the external jugular vein, which runs parallel 
with the posterior border of the muscle in this situation, or the anterior jugular vein, which 
crosses beneath it. If the external jugular vein lies near the muscle, it is safer to make the 
first puncture at the outer side of the tendon, and introduce a blunt tenotome from without 
inward. Many surgeons prefer dividing the muscle by open incision, because by this method 
all of the contracted fibres, muscular and facial, can be certainly and safely divided. An incision 
is made over the origin of the muscle, the origin is exposed, a director is passed underneath it, 
and it is then divided. With care and attention to asepsis this plan of treatment is devoid of 
risk, and in this way the accidental division of vessels can be avoided. Some of the fibres of 
the Sterno-mastoid muscle are occasionally torn during birth, especially in breech presenta- 
tions; this is accompanied by hemorrhage and formation of a swelling within the substance of 
the muscle. This by some is believed to be one of the causes of wry-neck, the scar tissue 
which is formed contracting and shortening the muscle. 
2. The Infra-hyoid Region (Figs. 269, 270). 
Depressors of the Os Hyoideum and Larynx 
Sterno-hyoid. 
Sterno-thyroid. 
Thyro-hyoid. 
Omo-hyoid. 
Dissection.-The muscles in this region may be exposed by removing the deep fascia from the 
front of the neck. In order to see the entire extent of the Omo-hyoid it is necessary to divide 
the sterno-mastoid at its centre, and turn its ends aside, and to detach the Trapezius from the 
clavicle and scapula. This, however, should not be done until the Trapezius has been dissected. 
The Stemo-hyoid (m. sternohyoideus) is a thin, narrow, ribbon-like muscle, 
which arises from the inner extremity of the clavicle, the posterior sterno- 
clavicular ligament, and the upper and posterior part of the first piece of the 
sternum; passing upward and inward, it is inserted, by short, tendinous fibres, 
into the lower border of the body of the hyoid bone. This muscle is separated, 
below, from its fellow by a considerable interval; but the two muscles come into 
contact with one another in the middle of their course, and from this upward 
lie side by side. It sometimes presents, immediately above its origin, a trans- 
verse tendinous intersection, like those in the Rectus abdominis. As a rule, 
two bursae, the stemo-hyoid bursae (bursae sternohyoidii), lie between the crico- 
thyroid membrane, on one hand, and the Sterno-hyoid muscle and the cervical 
fascia, on the other. Sometimes there is one large median bursa instead of two 
lateral bursae. Not unusually there is no bursa at all. 
Relations.-By its superficial surface, below, with the sternum, the sternal end 
of the clavicle, and the Sterno-mastoid; and above, with the Platysma and deep 
cervical fascia; by its deep surface, with the Sterno-thyroid, Crico-thyroid, and 392 
THE MUSCLES AND EASCEE 
Thyro-hyoid muscles, the thyroid gland, the superior thyroid vessels, the thyroid 
cartilage, the crico-thyroid and thyro-hyoid membranes. 
The Sterno-thyroid (m. sternothyreoideus) is situated beneath the preceding 
muscle, but is shorter and wider than it. It arises from the posterior surface of 
the first piece of the sternum, below the origin of the Sterno-hyoid, and from the 
edge of the cartilage of the first rib, occasionally of the second rib also, and is 
inserted into the oblique line on the side of the ala of the thyroid cartilage. 
This muscle is in close contact with its fellow at the lower part of the neck, and 
is occasionally traversed by a transverse or oblique tendinous intersection, like 
those in the Rectus abdominis. 
Symphysis 
of jaw. 
Scapula, i 
Sternum. 
Fig. 270.-Muscles of the neck. Anterior view. 
Relations.-By its anterior surface, with the Sterno-hyoid, Omo-hyoid, and 
Sterno-mastoid; by its posterior surface, from below upward, with the trachea, 
vena innominata, common carotid (and on the right side the arteria innominata), 
the thyroid gland and its vessels, and the lower part of the larynx and pharynx. 
The inferior thyroid vein lies along its inner bonier, a relation which it is impor- 
tant to remember in the operation of tracheotomy. On the left side the deep 
surface of the muscle is in relation to the cesophagus. 
The Thyro-hyoid (m. thyreohyoideus) is a small, quadrilateral muscle appear- 
ing like a continuation of the Sterno-thyroid. It arises from the oblique line on 
the side of the thyroid cartilage, and passes vertically upward to be inserted into 
the lower border of the body and greater cornu of the hyoid bone. The thyro- 
hyoid bursae (bursae thyreohyoidii) lie inferior to the greater cornua of the hyoid 
bone and upon the thyro-hyoid membrane. There is one bursa on each side 
beneath the corresponding Thyro-hyoid muscle. 
Relations.-By its external surface, with the Sterno-hyoid and Omo-hyoid 
muscles; by its internal surface, with the thyroid cartilage, the thyro-hyoid mem- 
brane, and the superior laryngeal vessels and nerve. THE SUPRA-HYOID REGION 
393 
The Omo-hyoid (m. omohyoideus) passes across the side of the neck, from 
the scapula to the hyoid bone. It consists of two fleshy bellies, united by a 
central tendon. It arises from the upper border of the scapula, and occasionally 
from the transverse ligament which crosses the suprascapular notch, its extent of 
attachment to the scapula varying from a few lines to an inch. From this origin 
the posterior belly (venter inferior) forms a flat, narrow fasciculus, which inclines 
forward and slightly upward across the lower part of the neck, behind the Sterno- 
mastoid muscle, where it becomes tendinous; it then changes its direction, forming 
an obtuse angle, and terminates in the anterior belly (venter superior), which 
passes almost vertically upward, close to the outer border of the Sterno-hyoid, 
to be inserted into the lower border of the body of the hyoid bone, just external to 
the insertion of the Sterno-hyoid. The central tendon of this muscle, which varies 
much in length and form, is held in position by a process of the deep cervical 
fascia, which includes it in a sheath. This process is prolonged down, to be 
attached to the clavicle and first rib. It is by this means that the angular form of 
the muscle is maintained. 
This muscle subdivides each of the two large triangles at the side of the neck 
into two smaller triangles; the two posterior ones being the posterior superior or 
occipital triangle, and the posterior inferior or subclavian triangle; the two anterior, 
the anterior superior or superior carotid triangle, and the anterior inferior or inferior 
carotid triangle. 
Relations.-By its superficial surface, with the Trapezius, the Sterno-mastoid, 
deep cervical fascia, Platysma, and integument; by its deep surface, with the 
Scaleni muscles, phrenic nerve, lower cervical nerves, which go to form the brachial 
plexus, the suprascapular vessels and nerve, sheath of the common carotid artery 
and internal jugular vein, the Sterno-thyroid and Thyro-hyoid muscles. 
Nerves.-The Thyro-hyoid is supplied by the hypoglossal; the other muscles 
of this group by branches from the loop of communication between the descendens 
and communicans hypoglossi. 
Actions.-These muscles depress the larynx and hyoid bone, after they have 
been drawn up with the pharynx in the act of deglutition. The Omo-hyoid 
muscles not only depress the hyoid bone, but carry it backward and to one side. 
It is concerned especially in prolonged inspiratory efforts; for by tensing the 
lower part of the cervical fascia it lessens the inward suction of the soft parts, 
which would otherwise compress the great vessels and the apices of the lungs. 
This action is synergistic with that of the Platysma. The Thyro-hyoid may act 
as an elevator of the thyroid cartilage when the hyoid bone ascends, drawing 
upward the thyroid cartilage, behind the hyoid bone. The Sterno-thyroid acts as 
a depressor of the thyroid cartilage. 
3. The Supra-hyoid Region (Figs. 269, 270). 
Elevators of the Os Hyoideum-Depressors of the Lower Jaw. 
Digastric. 
Stylo-hyoid. 
Mylo-hyoid. 
Genio-hyoid. 
Dissection.-To dissect these muscles a block should be placed beneath the back of the 
neck, and the head drawn backward and retained in that position. On the removal of the deep 
fascia the muscles are at once exposed. 
The Digastric (m. digastricus) consists of two fleshy bellies united by an inter- 
mediate, rounded tendon. It is a small muscle, situated below the side of the 
body of the lower jaw, and extending, in a curved form, from the side of the 
head to the symphysis of the jaw. The posterior belly (venter posterior), longer 
than the anterior, arises from the digastric groove on the inner side of the mas- 
toid process of the temporal bone, and passes downward, forward, and inward. 394 
THE MUSCLES AND FASCIAE 
The anterior belly {venter anterior) arises from a depression on the inner side 
of the lower border of the jaw, close to the symphysis, and passes downward 
and backward. The two bellies terminate in the central tendon which per- 
forates the Stylo-hyoid, and is held in connection with the side of the body 
and the greater cornu of the hyoid bone by a fibrous loop, lined by a synovial 
membrane. A broad aponeurotic layer is given off from the tendon of the 
Digastric on each side, which is attached to the body and great cornu of the 
hyoid bone: this is termed the supra-hyoid aponeurosis. It forms a strong layer 
of fascia between the anterior portion of the two muscles, and a firm investment 
for the other muscles of the supra-hyoid region which lie deeper. 
The Digastric muscle divides the anterior superior triangle of the neck into 
two smaller triangles; the upper, or submaxillary triangle, being bounded, above, by 
the lower border of the body of the jaw, and a line drawn from its angle to the 
mastoid process; below, by the posterior belly of the Digastric and the Stylo- 
hyoid muscles; in front, by the middle line of the neck and the anterior belly of the 
Digastric, the lower or superior carotid triangle being bounded above by the poste- 
rior belly of the Digastric, behind by the Sterno-mastoid, below by the anterior 
belly of the Omo-hyoid. 
Relations.-By its superficial surface, with the mastoid process, the Platysma, 
Sterno-mastoid, part of the Splenius, Trachelo-mastoid, and Stylo-hyoid muscles, 
and the parotid gland. By its deep surface, the anterior belly lies on the Mylo- 
hyoid; the posterior belly on the Stylo-glossus, Stylo-pharyngeus, and Hyo-glossus 
muscles, the external carotid artery and its occipital, lingual, facial, and ascending 
pharyngeal branches, the internal carotid artery, internal jugular vein, and hypo- 
glossal nerve. 
The Stylo-hyoid (m. stylohyoideus) is a small, slender muscle, lying in front 
of, and above, the posterior belly of the Digastric. It arises from the back and 
outer surface of the styloid process of the temporal bone, near the base; and, 
passing downward and forward, is inserted into the body of the hyoid bone, 
just at its junction with the greater cornu, and immediately above the Omo- 
hyoid. This muscle is perforated, near its insertion, by the tendon of the 
Digastric. 
Relations.-By its superficial surface above with the parotid gland and deep 
cervical fascia; below it is superficial, being situated immediately beneath the deep 
cervical fascia. By its deep surface, with the posterior belly of the Digastric, the 
external carotid artery, with its lingual and facial branches, the Hyo-glossus 
muscle, and the hypoglossal nerve. 
The Stylo-hyoid Ligament (lig amentum stylohyoideus).-In connection with the 
Stylo-hyoid muscle may be described a ligamentous band, the stylo-hyoid ligament. 
It is a fibrous cord, often containing a little cartilage in its centre, which continues 
the styloid process down to the hyoid bone, being attached to the tip of the former 
and the small cornu of the latter. It is often more or less ossified, and in many 
animals forms a distinct bone, the epihyal. 
The anterior belly of the Digastric should be removed, in order to expose the next muscle. 
The Mylo-hyoid (m. mylohyoideus) (Fig. 271) is a flat, triangular muscle, 
situated immediately beneath the anterior belly of the Digastric, and forming, 
with its fellow of the opposite side, a muscular floor for the cavity of the mouth. 
It arises from the whole length of the mylo-hyoid ridge of the lower jaw, extend- 
ing from the symphysis in front to the last molar tooth behind. The posterior 
fibres pass inward and slightly downward, to be inserted into the body of the 
hyoid bone. The middle and anterior fibres are inserted into a median fibrous 
raphe, extending from the symphysis of the lower jaw to the hyoid bone, where 
they join at an angle with the fibres of the opposite muscle. The median raphe THE SUPRA-HYOID REGION 
395 
is sometimes wanting; the muscular fibres of the two sides are then directly 
continuous with one another. 
Relations.-By its cutaneous or under surface, with the Platysma, the anterior 
belly of the Digastric, the supra-hyoid aponeurosis, the submaxillary gland, sub- 
mental vessels, and mylo-hyoid vessels and nerve; by its deep or superior surface, 
with the Genio-hyoid, part of the Hyo-glossus and Stylo-glossus muscles, the hypo- 
glossal and lingual nerves, the submaxillary ganglion, the sublingual gland, the 
deep portion of the submaxillary gland, and Wharton's duct; the sublingual and 
ranine vessels, and the buccal mucous membrane. 
Dissection.-The Mylo-hyoid should now be removed, in order to expose the muscles which 
lie beneath; this is effected by reflecting it from its attachments to the hyoid bone and jaw, and 
separating it by a vertical incision from its fellow of the opposite side. 
Fig. 271.-Mylo-hyoid muscle. (Poirier and Charpy.) 
The Genio-hyoid (m. geniohyoideus) (Fig. 272) is a narrow, slender muscle, 
situated immediately beneath1 the inner border of the preceding. It arises from 
the inferior genial tubercle on the inner side of the symphysis of the jaw, and 
passes downward and backward, to be inserted into the anterior surface of the 
body of the hyoid bone. This muscle lies in close contact with its fellow of the 
opposite side, and increases slightly in breadth as it descends. 
Relations.-It is covered by the Mylo-hyoid and lies along the lower border 
of the Genio-hyo-glossus. 
Nerves.-The anterior belly of the Digastric is supplied by the mylo-hyoid 
branch of the inferior dental; its posterior belly, by the facial; the Stylo-hyoid 
is supplied by the facial; the Mylo-hyoid, by the mylo-hyoid branch of the 
inferior dental; the Genio-hyoid, by the hypoglossal. 
Actions.-This group of muscles performs two very important actions. They 
raise the hyoid bone, and with it the base of the tongue, during the act of degluti- 
tion; or, when the hyoid bone is fixed by its depressors and those of the larynx, 
they depress the lower jaw. During the first act of deglutition, when the mass 
is being driven from the mouth into the pharynx, the hyoid bone, and with it the 
tongue, is carried upward and forward by the anterior belly of the Digastric, the 
Mylo-hyoid, and Genio-hyoid muscles. In the second act, when the mass is pass- 
1 This refers to the depth of the muscles from the skin in the order of dissection. In the erect position of 
the body the Genio-hyoid is above the Mylo-hyoid. 396 
THE MUSCLES AND FASCIA 
ing through the pharynx, the direct elevation of the hyoid bone takes place by the 
combined action of all the muscles; and after the food has passed, the hyoid bone 
is carried upward and backward by the posterior belly of the Digastric and Stylo- 
hyoid muscles, which assist in preventing the return of the morsel into the mouth. 
4. The Lingual Region (Figs. 272, 273, 274). 
Genio-hyo-glossus. 
Hyo-glossus. 
Stylo-glossus. 
Palato-glossus. 
Chondro-glossus. 
Dissection.-After completing the dissection of the preceding muscles, saw through the 
lower jaw just external to the symphysis. Then draw the tongue forward, and attach it, by a 
stitch, to the nose; when its muscles, which are thus put on the stretch, may be examined. 
Fig. 272.-Muscles of the tongue. Left side. 
The Genio-hyo-glossus (m. genioglossus) has received its name from its triple 
attachment to the jaw, hyoid bone, and tongue, but it is better to name it the 
Genio-glossus, since its attachment to the hyoid bone is very slight or altogether 
absent. It is a flat, triangular muscle, placed vertically on either side of the 
middle line, its apex corresponding with its point of attachment to the lower jaw, its 
base with its insertion into the tongue and hyoid bone. It arises by a short tendon 
from the superior genial tubercle on the inner side of the symphysis of the jaw, im- 
mediately above the Genio-hyoid; from this point the muscle spreads out in a fan- 
like form, a few of the inferior fibres passing downward, to be attached by a thin 
aponeurosis into the upper part of the body of the hyoid bone, a few fibres passing 
between the Hyo-glossus and Chondro-glossus to blend with the Constrictor mus- 
cles of the pharynx; the middle fibres passing backward, and the superior ones 
upward and forward, to enter the whole length of the under surface of the tongue, 
from the base to the apex. The two muscles lie on either side of the median plane; THE LINGUAL REGION 
397 
behind (Fig. 273), they are quite distinct from each other, and are separated at 
their insertion into the under surface of the tongue by a tendinous raph£, which 
extends through the middle of the organ; in front, the two muscles are more or 
less blended: distinct fasciculi are to be seen passing off from one muscle, 
crossing the middle line, and intersecting with bundles of fibres derived from 
the muscle on the other side. 
Relations.-By its internal surface it is in contact with its fellow of the opposite 
side; by its external surface, with the Inferior lingualis, the Hyo-glossus, the lin- 
gual artery and hypoglossal nerve, the lingual 
nerve, and sublingual gland; by its upper bor- 
der, with the mucous membrane of the floor of 
the mouth (fraenum linguae); by its lower border 
with the Genio-hyoid. 
The Hyo-glossus (m. hyoglossus) is a thin, 
flat, quadrilateral muscle which arises from the 
side of the body and whole length of the greater 
cornu of the hyoid bone, and passes almost ver- 
tically upward to enter the side of the tongue, 
between the Stylo-glossus and Lingualis. Those 
fibres of this muscle which arise from the body 
are directed upward and backward, overlap- 
ping those arising from the greater cornu, which 
are directed upward and forward. 
Relations.-By its external surface, with the 
Digastric, the Stylo-hyoid, Stylo-glossus, and 
Mylo-hyoid muscles, the submaxillary ganglion, 
the lingual and hypo-glossal nerves, Wharton's 
duct, the ranine vein, the sublingual gland, and 
the deep portion of the submaxillary gland. By 
its deep surface, with the Stylo-hyoid ligament, 
the Genio-hyo-glossus, Lingualis, and Middle 
constrictor, the lingual vessels, and the glosso- 
pharyngeal nerve. 
The Chondro-glossus (nt. chondroglossus) is 
a distinct muscular slip, though it is sometimes 
described as a part of the Hyo-glossus, from 
which, however, it is separated by the fibres of 
the Genio-hyo-glossus, which pass to the side of 
the pharynx. It is about three-quarters to an inch in length, and arises from the 
inner side and base of the lesser cornu and contiguous portion of the body of the 
hyoid bone, and passes directly upward to blend with the intrinsic muscular 
fibres of the tongue, between the Hyo-glossus and Genio-hyo-glossus. A small 
slip of muscular fibre is occasionally found, arising from the cartilage triticia 
in the thyro-hyoid ligament, and passing upward and forward to enter the 
tongue with the hindermost fibres of the Hyo-glossus. 
The Stylo-glossus (m. styloglossus), the shortest and smallest of the three styloid 
muscles, arises from the anterior and outer side of the styloid process, near its apex, 
and from the stylo-mandibular ligament, to which its fibres, in most cases, are 
attached by a thin aponeurosis. Passing downward and forward between the inter- 
nal and external carotid arteries, and becoming nearly horizontal in its direction, 
it divides upon the side of the tongue into two portions: one longitudinal, which 
enters the side of the tongue near its dorsal surface, blending with the fibres of the 
Lingualis in front of the Hyo-glossus; the other oblique, which overlaps the 
Hyoglossus muscle and decussates with its fibres. 
CHON DRO-G LOSS US. 
Fig. 273.-Muscles of the tongue from be- 
low. (From a preparation in the Museum of 
the Royal College of Surgeons of England.) 398 
THE MUSCLES AND FASCHE 
Relations.-By its external surface, from above downward, with the parotid 
gland, the Internal pterygoid muscle, the lingual nerve, and the mucous membrane 
of the mouth; by its internal surface, with the tonsil, the Superior constrictor, and 
the Hyo-glossus muscle. 
The Palato-glossus or Constrictor Isthmi Faucium (m. glossopalatinus}, 
although it is one of the muscles of the tongue, serving to draw its base upward 
during the act of deglutition, is more nearly associated with the soft palate, both 
in its situation and function; it will consequently be described with that group of 
muscles. 
Nerves.-The Palato-glossus is probably innervated by the spinal accessory 
nerve, through the pharyngeal plexus; the remaining muscles of this group, by the 
hypo-glossal. 
Muscular Substance of the Tongue (Figs. 273, 274, and 275).-The muscular 
fibres of the tongue run in various directions. These fibres are divided into two 
sets-Extrinsic and Intrinsic. The extrinsic muscles of the tongue are those 
which have their origin external, and only their terminal fibres contained in the 
substance of the organ. They are: the Stylo-glossus, the Hyo-glossus, the Palato- 
glossus, the Genio-hyo-glossus, and part of the 
Superior constrictor of the pharynx (Pharyngeo- 
glossus). The intrinsic muscles are those which 
are contained entirely within the tongue, and 
form the greater part of its muscular struc- 
ture. 
CUT EDGE OF SUPERIOR LINGUALIS. 
Fig. 275.-Coronal section of tongue. Showing intrinsic 
muscles, a, lingual artery; b, Inferior lingualis, cut through; 
c, fibres of Hyo-glossus; d, oblique fibres of Stylo-glossus; e, in- 
sertion of Transverse lingualis; f, Superior lingualis; g, papillae 
to tongue; h, vertical fibres of Genio-hyo-glossus intersecting 
Transverse lingualis; l, septum. (Altered from Krause.) 
Fig. 274.-Muscles on the dorsum of the 
tongue. 
The tongue consists of symmetrical halves separated from each other in the 
middle line by a fibrous septum (septum linguce). Each half is composed of 
muscular fibres arranged in various directions, containing much interposed fat, 
and supplied by vessels and nerves. 
To demonstrate the various fibres of the tongue, the organ should be subjected to 
prolonged boiling, in order to soften the connective tissue; the dissection may then 
be commenced from the dorsum (Figs. 274 and 275). Immediately beneath the 
mucous membrane is a submucous, fibrous layer, into which the muscular fibres 
which terminate on the surface of the tongue are inserted. Upon removing this, THE LINGUAL REGION 
399 
with the mucous membrane, the first stratum of muscular fibres is exposed. 
This belongs to the group of intrinsic muscles, and has been named the Superior 
lingualis (m. longitudinalis superior). It consists of a thin layer of oblique and 
longitudinal fibres which arise from the submucous fibrous layer, close to the 
Epiglottis, and from the fibrous septum, and pass forward and outward to the 
edges of the tongue. Between its fibres pass some vertical fibres derived from 
the Genio-hyo-glossus and from the vertical intrinsic muscle, which will be de- 
scribed later on. Beneath this layer is the second stratum of muscular fibres, 
derived principally from the extrinsic muscles. In front it is formed by the fibres 
derived from the Stylo-glossus, running along the side of the tongue, and sending 
one set of fibres over the dorsum which run obliquely forward and inward to the 
middle line, and another set of fibres seen at a later period of the dissection, on to 
the under surface of the sides of the anterior part of the tongue, which run forward 
and inward, between the fibres of the Hyo-glossus, to the middle line. Behind this 
layer of fibres, derived from the Stylo-glossus, are fibres derived from the Hyo- 
glossus, assisted by some few fibres of the Palato-glossus. The Hyo-glossus, enter- 
ing the side of the under surface of the tongue, between the Stylo-glossus and 
Inferior lingualis, passes round its margin and spreads out into a layer on the dor- 
sum, which occupies the middle third of the organ, and runs almost transversely 
inward to the septum. It is reinforced by some fibres from the Palato-glossus; 
other fibres of this muscle pass more deeply and intermingle with the next layer. 
The posterior part of the second layer of the muscular fibres of the tongue is 
derived from those fibres of the Hyo-glossus which arise from the lesser cornu of 
the hyoid bone, and are here described as a separate muscle-the Chondro-glossus. 
The fibres of this muscle are arranged in a fan-shaped manner, and spread out over 
the posterior third of the tongue. Beneath this layer is the great mass of the intrin- 
sic muscles of the tongue, intersected at right angles by the terminal fibres of one of 
the extrinsic muscles-the Genio-hyo-glossus. This portion of the tongue is paler 
in color and softer in texture than that already described, and is sometimes 
designated the medullary portion in contradistinction to the firmer superficial part, 
which is termed the cortical portion. It consists largely of transverse fibres, the 
Transverse lingualis (m. transversus linguae), and of vertical fibres, the Vertical 
lingualis (m. verticalis linguae). The Transverse lingualis forms the largest portion 
of the third layer of muscular fibres of the tongue. The fibres arise from the 
median septum, and pass outward to be inserted into the submucous fibrous layer 
at the sides of the tongue. Intermingled with these transverse intrinsic fibres are 
transverse extrinsic fibres derived from the Palato-glossus and the Superior con- 
strictor of the pharynx. These transverse extrinsic fibres, however, run in the 
opposite direction, passing inward toward the septum. Intersecting the transverse 
fibres are a large number of vertical fibres derived partly from the Genio-hyo- 
glossus and partly from intrinsic fibres, the Vertical lingualis. The fibres derived 
from the Genio-hyo-glossus enter the under surface of the tongue on each side of 
the median septum from base to apex. They ascend in a radiating manner to the 
dorsum, being inserted into the submucous fibrous layer covering the tongue on 
each side of the middle line. The Vertical lingualis is found only at the borders 
of the forepart of the tongue, external to the fibres of the Genio-hyo-glossus. 
Its fibres extend from the upper to the under surface of the organ, decussating 
with the fibres of the other muscles, and especially with the Transverse lingualis. 
The fourth layer of muscular fibres of the tongue consists partly of extrinsic fibres 
derived from the Stylo-glossus, and partly of intrinsic fibres, the Inferior lingualis 
(m. longitudinalis inferior). At the sides of the under surface of the organ are 
some fibres derived from the Stylo-glossus, which, as it runs forward at the side of 
the tongue, gives off fibres which, passing forward and inward between the fibres 
of the Hyo-glossus, form an inferior oblique stratum which joins in front with the 400 
THE MUSCLES AND FASCIAE 
anterior fibres of the Inferior lingualis. The Inferior lingualis is a longitudinal 
band, situated on the under surface of the tongue, and extending from the base to 
the apex of the organ. Behind, some of its fibres are connected with the body of 
the hyoid bone. It lies between the Hyo-glossus and the Genio-hyo-glossus, and 
in front of the Hyo-glossus it enters into relation with the Stylo-glossus, with the 
fibres of which it blends. It is in relation by its under surface with the ranine 
artery. 
Surgical Anatomy.-The fibrous septum which exists between the two halves of the tongue 
is very complete, so that the anastomosis between the two lingual arteries is not very free, 
a fact often illustrated by injecting one-half of the tongue with colored size, while the other 
half is left uninjected or is injected with size of a different color. 
This is'a point of considerable importance in connection with removal of one-half of the 
tongue for cancer, an operation which is now frequently resorted to when the disease is strictly 
confined to one side of the anterior portion of the tongue. If the mucous membrane is divided 
longitudinally exactly in the middle line, the tongue can be split into halves along the median 
raph^ without any appreciable hemorrhage, and the diseased half can then be removed. 
Actions.-The movements of the tongue, although numerous and complicated, 
may be understood by carefully considering the direction of the fibres of its 
muscles. The Genio-hyo-glossi muscles, by means of their posterior fibres, draw 
the base of the tongue forward, so as to protrude the apex from the mouth. The 
anterior fibres draw the tongue back into the mouth. The whole length of these 
two muscles, acting along the middle line of the tongue, draw it downward, so as to 
make it concave from side to side, forming a channel along which fluids may pass 
toward the pharynx, as in sucking. The Ilyo-glossi muscles depress the tongue 
and draw down its sides, so as to render it convex from side to side. The Stylo- 
glossi muscles draw the tongue upward and backward. The Palato-glossi muscles 
draw the base of the tongue upward. With regard to the intrinsic muscles, both 
the Superior and Inferior linguales tend to shorten the tongue, but the former, in 
addition, turn the tip and sides upward so as to render the dorsum concave, while 
the latter pull the tip downward and cause the dorsum to become convex. The 
Transverse lingualis narrows and elongates the tongue, and the Vertical lingualis 
flattens and broadens it. The complex arrangement of the muscular fibres of 
the tongue, and the various directions in which they run, give to this organ the 
power of assuming the various forms necessary for the enunciation of the different 
consonantal sounds; and Dr. Macalister states that "there is reason to believe 
that the musculature of the tongue varies in different races owing to the hereditary 
practice and habitual use of certain motions required for enunciating the several 
vernacular languages." 
5. The Pharyngeal Region (Figs. 276, 277, 27S). 
Inferior constrictor. 
Middle constrictor. 
Superior constrictor. 
Stylo-pharyngeus. 
Palato-pharyngeus. 
Salpingo-pharyngeus. 
(See next section.) 
Dissection (Fig. 276).-In order to examine the muscles of the pharynx, cut through the 
trachea and oesophagus just above the sternum, and draw them upward by dividing the loose 
areolar tissue connecting the pharynx with the front of the vertebral column. The parts being 
drawn well forward, apply the edge of the saw immediately behind the styloid processes, and 
saw the base of the skull through from below upward. The pharynx and mouth should then 
be stuffed with tow, in order to distend its cavity and render the muscles tense and easier of 
dissection. 
The Inferior Constrictor (m. constrictor pharyngis inferior), the most superficial 
and thickest of the three constrictors, arises from the sides of the cricoid and 
thyroid cartilages. To the cricoid cartilage it is attached in the interval between THE PHARYNGEAL REGION 
401 
the Crico-thyroid muscle in front and the articular facet for the thyroid cartilage 
behind. To the thyroid cartilage it is attached to the oblique line on the side of 
the great ala, the cartilaginous surface behind it, nearly as far as its posterior border, 
and to the inferior cornu. From these attachments the fibres spread backward and 
inward, to be inserted into the fibrous raph£ in the posterior median line of the 
pharynx. The inferior fibres are horizontal, and continuous with the fibres of the 
(esophagus: the rest ascend, increasing in obliquity, and overlap the Middle con- 
strictor. 
Relations.-It is covered by a thin membrane which surrounds the entire 
pharynx, bucco-pharyngeal fascia {fascia buccopharyngea). Behind, it is in 
relation with the vertebral column 
and the prevertebral fascia and mus- 
cles; laterally, with the thyroid gland, 
the common carotid artery, and the 
Sterno-thyroid muscle; by its internal 
surface, with the Middle constrictor, 
the Stylo-pharyngeus, Palato-pharyn- 
geus, the fibrous coat and mucous 
membrane of the pharynx. The in- 
ternal laryngeal nerve and the laryn- 
geal branch of the Superior Thyroid 
artery pass near the upper border, and 
the inferior, or recurrent laryngeal 
nerve, and the laryngeal branch of the 
Inferior Thyroid artery, beneath the 
lower border of this muscle, previous to 
their entering the larynx. 
The Middle Constrictor {m. constric- 
tor pharyngis medius) is a flattened, 
fan-shaped muscle, smaller than the 
preceding. It arises from the whole 
length of the upper border of the 
greater cornu of the hyoid bone, from 
the lesser cornu, and from the stylo- 
hyoid ligament. The fibres diverge 
from their origin, the lower ones de- 
scending beneath the Inferior con- 
strictor, the middle fibres passing 
transversely, and the upper fibres ascending and overlapping the Superior con- 
strictor. The muscle is inserted into the posterior median fibrous raphe, blending 
in the middle line with the one of the opposite side. 
Relations.-Between this muscle and the Superior constrictor are the glosso- 
pharyngeal nerve, the Stylo-pharyngeus muscle and the stylo-hyoid ligament; 
and between it and the Inferior constrictor is the superior laryngeal nerve. 
Behind, it lies on the vertebral column, the Longus colli, and the Rectus capitis 
.anticus major. On each side it is in relation with the carotid vessels, the pharyn- 
geal plexus, and some lymphatic glands. Near its origin it is covered by the 
Hyo-glossus, the lingual vessels being placed between the two muscles. It lies 
upon the Superior constrictor, the Stylo-pharyngeus, the Palato-pharyngeus, the 
fibrous coat, and the mucous membrane of the larynx. 
'rhe Superior Constrictor {m. constrictor pharyngis superior) is a quadrilateral 
muscle, thinner and paler than the other constrictors, and situated at the upper 
part of the pharynx. It arises from the lower third of the posterior margin of the 
internal pterygoid plate and its hamular process, from the contiguous portion of the 
Fig. 276.-Muscles of the pharynx. External view. 402 
THE MUSCLES AND FASCIAE 
palate bone and the reflected tendon of the Tensor palati muscle, from the pterygo- 
maxillary ligament, from the alveolar process above the posterior extremity of the 
mylo-hyoid ridge, and by a few fibres from the side of the tongue. From these 
points the fibres curve backward, to be inserted into the median raphe, being also 
prolonged by means of a fibrous aponeurosis to the pharyngeal spine on the basilar 
process of the occipital bone. The superior fibres arch beneath the Levator palati 
and the Eustachian tube, the interval between the upper border of the muscle and 
the basilar process being deficient in muscular fibres and closed by a portion 
of the pharyngeal aponeurosis (fascia pharyngobasilaris). This interval is known as 
the sinus of Morgagni. 
ACCESSORY BUNDLE 
FROM PETROSAL POR-. 
TION OF TEMPORAL 
STYLOID PROCESS- 
EXPANSION OF 
STYLO-PHARYNGEUS 
EXPANSION OF 
PALATO-PH ARYNGEUS 
Fig. 277.-The muscles of the pharynx. On the right side most of the inferior constrictor has been removed, 
on the left side the Digastric and Stylo-hyoid have been removed. (Spalteholz.) 
Relations.-By its outer surface, with the prevertebral fascia and muscles, 
the vertebral column, the internal carotid and ascending pharyngeal arteries, the 
internal jugular vein and pharyngeal venous plexus, the glosso-pharyngeal, pneu- 
mogastric, spinal accessory, hypoglossal, lingual, and sympathetic nerves, the 
Middle constrictor and Internal pterygoid muscles, the Styloid process, the Stylo- THE PALATAL LEGION 
403 
hyoid ligament, and the Stylo-pharyngeus. By its internal surjace, with the 
Palato-pharyngeus, the tonsil, the fibrous coat and mucous membrane of the 
pharynx. 
The Stylo-pharyngeus (m. stylopharyngeus) is a long, slender muscle, round 
above, broad and thin below. It arises from the inner side of the base of the 
styloid process of the temporal bone, passes downward along the side of the 
pharynx between the Superior and Middle constrictors, and spreads out beneath 
the mucous membrane, where some of its fibres are lost in the Constrictor muscles; 
and others, joining with the Palato-pharyngeus, are inserted into the posterior 
border of the thyroid cartilage. The glosso-pharyngeal nerve runs on the outer 
side of this muscle, and crosses over it in passing forward to the tongue. 
Relations.-Externally, with the Stylo-glossus muscle, the parotid gland, the 
external carotid artery, and the Middle constrictor; internally, with the internal 
carotid, the internal jugular vein, the Superior constrictor, Palato-pharyngeus, 
and mucous membrane. 
Nerves.-The Constrictors are supplied by branches from the pharyngeal 
plexus. The Inferior constrictor also receives an additional branch from the 
external laryngeal nerve and one from the recurrent laryngeal. The Stylo- 
pharyngeus is supplied by the glosso-pharyngeal nerve. 
Actions.-When deglutition is about to be performed, the pharynx is drawn 
upward and dilated in different directions, to receive the morsel propelled into it 
from the mouth. The Stylo-pharyngei, which are much farther removed from 
one another at their origin than at their insertion, draw the sides of the pharynx 
upward and outward, and so increase its transverse diameter, its breadth in the 
antero-posterior direction being increased by the larynx and tongue being carried 
forward in their ascent. As soon as the morsel is received in the pharynx, the 
Elevator muscles relax, the bag descends, and the Constrictors contract upon 
the morsel, and convey it gradually downward into the oesophagus. Besides its 
action in deglutition, the pharynx also exerts an important influence in the modu- 
lation of the voice, especially in the production of the higher tones. 
6. The Palatal Region (Fig. 278.) 
Levator palati. 
Tensor palati. 
Azygos uvulae. 
Palato-glossus. 
Palato-pharyngeus. 
Salpingo-pharyngeus. 
Dissection (Fig. 278).-Lay open the pharynx from behind by a vertical incision extending 
from its upper to its lower part, and partially divide the occipital attachment by a transverse 
incision on each side of the vertical one; the posterior surface of the soft palate is then exposed. 
Having fixed the uvula so as to make it tense, the mucous membrane and glands should be 
carefully removed from the posterior surface of the soft palate, and the muscles of this part 
are at once exposed. 
The Levator Palati (m. levator veli palatini) is a long, thick, rounded muscle, 
placed on the outer side of the posterior nares. It arises from the under surface of 
the apex of the petrous portion of the temporal bone, and from the inner surface 
of the cartilaginous portion of the Eustachian tube; after passing into the pharynx, 
above the upper concave margin of the Superior constrictor, it passes obliquely 
downward and inWard, its fibres spreading out in the soft palate as far as the 
middle line, where they blend with those of the opposite side. 
Relations.-Externally, with the Tensor palati and Superior constrictor and 
Eustachian tube; internally, with the mucous membrane of the pharynx; pos- 
teriorly, with the posterior fasciculus of the Palato-pharyngeus, the Azygos uvulae, 
and the mucous lining of the soft palate. 404 
THE MUSCLES AND EASCLE 
The Circumflexus or Tensor Palati (m. tensor veli palatini) is a broad, thin, 
ribbon-like muscle, placed on the outer side of the Levator palati, and consisting of 
a vertical and a horizontal portion. The vertical portion arises by a flat lamella 
from the scaphoid fossa at the base of the internal pterygoid plate; from the spine 
of the sphenoid and the outer side of the cartilaginous portion of the Eustachian 
tube: descending vertically between the internal pterygoid plate and the inner sur- 
face of the Internal pterygoid muscle, it terminates in a tendon, which winds round 
the hamular process, being retained in this situation by some of the fibres of origin 
of the Internal pterygoid muscle. Between the hamular process and the tendon is 
a small bursa (bursa m. tensoris veli palati). The tendon or horizontal portion then 
Fig. 278.-Muscles of the soft palate, the pharynx being laid open from behind. 
passes horizontally inward, and is inserted into a broad aponeurosis, the palatine 
aponeurosis, and into the transverse ridge on the horizontal portion of the palate 
bone. 
Relations.-Externally, with the Internal pterygoid; internally, with the Levator 
palati, from which it is separated by the Eustachian tube and Superior constrictor 
and with the internal pterygoid plate. In the soft palate its tendon and the pala- 
tine aponeurosis are anterior to those of the Levator palati, being covered by the 
Palato-glossus and the mucous membrane. 
Palatine Aponeurosis.-Attached to the posterior border of the hard palate is 
a thin, firm, fibrous lamella which supports the muscles and gives strength to the 
soft palate. It is thicker above than below, where it becomes very thin and 
difficult to define. Laterally, it is continuous with the pharyngeal aponeurosis. THE PALATAL REGION 
405 
rhe Azygos Uvulae (m. uvulae) is not a single muscle, as would be inferred from 
its name, but a pair of narrow cylindrical fleshy fasciculi placed on either side of the 
median line of the soft palate. Each muscle arises from the posterior nasal spine 
of the palate bone and from the contiguous tendinous aponeurosis of the soft palate, 
and descends to be inserted into the uvula. 
Relations.-Anteriorly, with the tendinous expansion of the Levatores palati; 
behind, with the posterior fasciculus of the Palato-pharyngeus and the mucous 
membrane. 
The next two muscles are exposed by removing the mucous membrane from the pillars of 
the fauces throughout nearly their whole extent. 
The Palato-glossus or the Constrictor Isthmi Faucium (m. glossopalatinus) 
is a small fleshy fasciculus, narrower in the middle than at either extremity, 
forming, with the mucous membrane covering its surface, the anterior pillar of 
the soft palate. It arises from the anterior surface of the soft palate on each 
side of the uvula, and, passing downward, forward, and outward in front of the 
tonsil, is inserted into the side of the tongue, some of its fibres spreading over 
the dorsum, and others passing deeply into the substance of the organ to inter- 
mingle with the Transverse lingualis. In the soft palate the fibres of this muscle 
are continuous with those of the muscle of the opposite side. 
The Palato-pharyngeus ^n. pharyngopalatinus) is a long, fleshy fasciculus, 
narrower in the middle than at either extremity, forming, with the mucous 
membrane covering its surface, the posterior pillar of the soft palate. It is sepa- 
rated from the Palato-glossus by an angular interval, in which the tonsil is 
lodged. It arises from the soft palate by an expanded fasciculus, which is 
divided into two parts by the Levator palati and Azygos uvulae. The posterior 
fasciculus lies in contact with the mucous membrane, and also joins with the 
corresponding muscle in the middle line; the anterior fasciculus, the thicker, lies 
in the soft palate between the Levator and Tensor, and joins in the middle line 
the corresponding part of the opposite muscle. Passing outward and downward 
behind the tonsil, the Palato-pharyngeus joins the Stylo-pharyngeus, and is 
inserted with that muscle into the posterior border of the thyroid cartilage, some 
of its fibres being lost on the side of the pharynx, and others passing across the 
middle line posteriorly to decussate with the muscle of the opposite side. 
Relations.-In the soft palate its posterior surface is covered by mucous mem- 
brane, from which it is separated by a layer of palatine glands. By its anterior 
surface it is in relation with the Tensor palati. Where it forms the posterior pillar 
of the fauces it is covered by mucous membrane, excepting on its outer surface. In 
the pharynx it lies between the mucous membrane and the Constrictor muscles. 
The Salpingo-pharyngeus arises from the inferior part of the Eustachian tube 
near its orifice; it passes downward and blends with the posterior fasciculus of 
the Palato-pharyngeus. 
In a dissection of the soft palate from its posterior or nasal surface to its ante- 
rior or oral surface, the muscles would be exposed in the following order-viz., the 
posterior fasciculus of the Palato-pharyngeus, covered over by the mucous mem- 
brane reflected frorh the floor of the nasal fossae; the Azygos uvulae; the Levator 
palati; the anterior fasciculus of the Palato-pharyngeus; the aponeurosis of the 
Tensor palati, and the Palato-glossus, covered over by a reflection from the oral 
mucous membrane. 
Nerves.-The Tensor palati is supplied by a branch from the otic ganglion; 
the remaining muscles of this group are in all probability supplied by the internal 
branch of the spinal accessory, whose fibres are distributed along with certain 
branches of the pneumogastric through the pharyngeal plexus.1 It is possible, 
1 Journal of Anatomy and Physiology, vol. xxiii. p. 523. 406 
THE MUSCLES AND FASCIAE 
however, that the Levator palati may be supplied by the facial through the Petrosal 
branch of the Vidian. 
Actions.-During the first stage of deglutition the morsel of food is driven 
back into the fauces by the pressure of the tongue against the hard palate, the 
base of the tongue being, at the same time, retracted, and the larynx raised with 
the pharynx, and carried forward under it. During the second stage the entrance 
to the larynx is closed, not, as was formerly supposed, by the folding backward 
of the epiglottis over it, but, as Anderson Stuart has shown, by the drawing 
forward of the arytenoid cartilages toward the cushion of the epiglottis-a move- 
ment produced by the contraction of the External thyro-arytenoid, the Arytenoid, 
and Aryteno-epiglottidean muscles. 
The morsel of food after leaving the tongue passes on to the posterior or laryn- 
geal surface of the epiglottis, and glides along this for a certain distance;1 then 
the Palato-glossi muscles, the constrictors of the fauces, contract behind the food; 
the soft palate is slightly raised by the Levator palati, and made tense by the 
Tensor palati; and the Palato-pharyngei, by their contraction, pull the pharynx 
upward over the morsel of food, and at the same time come nearly together, the 
uvula filling up the slight interval between them. By these means the food is 
prevented passing into the upper part of the larynx or the posterior nares; at 
the same time the latter muscles form an inclined plane, directed obliquely down- 
ward and backward, along the under surface of which the morsel descends into 
the lower part of the pharynx. The Salpingo-pharyngeus raises the upper and 
lateral part of the pharynx-i. e., that part which is above the point where the 
Stylo-pharyngeus is attached to the pharynx. 
Surgical Anatomy.-The muscles of the soft palate should be carefully dissected, the rela- 
tions they bear to the surrounding parts especially examined, and their action attentively studied 
upon the dead subject, as the surgeon is required to divide one or more of these muscles in the 
operation of staphylorraphy. Sir W. Fergusson was the first to show that in the congenital 
deficiency called cleft palate the edges of the fissure are forcibly separated by the action of the 
Levatores palati and Palato-pharyngei muscles, producing very considerable impediment to the 
healing process after the performance of the operation for uniting their margins by adhesion; he 
consequently recommended the division of these muscles as one of the most important steps in 
the operation. This he effected by an incision made with a curved knife introduced behind the 
soft palate. The incision is to be half-way between the hamular process and Eustachian tube 
and perpendicular to a line drawn between them. This incision perfectly accomplishes the 
division of the Levator palati. The Palato-pharyngeus may be divided by cutting across the 
posterior pillar of the soft palate, just below the tonsil, with a pair of blunt-pointed curved 
scissors; and the anterior pillar may be divided also. To divide the Levator palati the plan 
recommended by Mr. Pollock is to be greatly preferred. The soft palate being put upon the 
stretch, a double-edged knife is passed through it just on the inner side of the hamular process 
and above the line of the Levator palati. The handle being now alternately raised and depressed, 
a sweeping cut is made along the posterior surface of the soft palate, and the knife withdrawn, 
leaving only a small opening in the mucous membrane on the anterior surface. If this operation 
is performed on the dead body and the parts afterward dissected, the Levator palati will be 
found completely divided. In the present day, however, this division of the muscles, as part 
of the operation of staphylorraphy, is not so much insisted upon. All tension is prevented by 
making longitudinal incisions on either side, parallel to the cleft and just internal to the hamular 
process, in such a position as to avoid the posterior palatine artery. 
7. The Anterior Vertebral Region (Fig. 279). 
Rectus capitis anticus major. 
Rectus capitis anticus minor. 
Rectus capitis lateralis. 
Longus colli. 
The Rectus Capitis Anticus Major or the Longus Capitis, broad and 
thick above, narrow below, appears like a continuation upward of the Sca- 
1 We now know that normal deglutition can be carried out when the epiglottis is so small that it cannot cover 
the opening into the larynx, or when it has been removed surgically. In such cases the sphincter muscles which 
surround the laryngeal aperture contract during swallowing and prevent the entrance of foreign bodies into the 
larynx.-Ed. THE ANTERIOR VERTEBRAL REGION 
407 
lenus anticus. It arises by four tendinous slips from the anterior tubercles of 
the transverse processes of the third, fourth, fifth, and sixth cervical vertebrae, and 
ascends, converging toward its fellow of the opposite side, to be inserted into the 
basilar process of the occipital bone. 
Relations.-By its anterior surface, with the pharynx, the sympathetic nerve, 
and the sheath enclosing the internal and common carotid artery, internal jugular 
vein, and pneumogastric nerve; by its posterior surface, with the Longus colli, the 
Rectus capitis anticus minor, and the upper cervical vertebrae. 
Fig. 279.-The prevertebral muscles. 
The Rectus Capitis Anticus Minor is a short, flat muscle, situated imme- 
diately behind the upper part of the preceding. It arises from the anterior 
surface of the lateral mass of the atlas and from the root of its transverse process, 
and, passing obliquely upward and inward, is inserted into the basilar process 
immediately behind the preceding muscle. 
Relations.-By its anterior surface, with the Rectus capitis anticus major; by 
its posterior surface, with the front of the occipito-atlantal articulation. 
The Rectus Capitis Lateralis is a short, flat muscle, which arises from the 
upper surface of the transverse process of the atlas, and is inserted into the under 
surface of the jugular process of the occipital bone. 
Relations.-By its anterior surface, with the internal jugular vein; by its pos- 
terior surface, with the vertebral artery. On its outer side lies the occipital artery; 
on its inner side, the suboccipital nerve. 
The Longus Colli is a long, flat muscle, situated on the anterior surface of the 
spine, between the atlas and the third dorsal vertebra. It is broad in the middle. 408 
THE MUSCLES AND FASCIAE 
narrow and pointed at each extremity, and consists of three portions: a superior 
oblique, an inferior oblique, and a vertical portion. The superior oblique portion 
arises from the anterior tubercles of the transverse processes of the third, fourth, 
and fifth cervical vertebra?, and, ascending obliquely inward, is inserted by a nar- 
row tendon into the tubercle on the anterior arch of the atlas. The inferior oblique 
portion, the smallest part of the muscle, arises from the front of the bodies of the 
first two or three dorsal vertebra?, and, ascending obliquely outward, is inserted 
into the anterior tubercles of the transverse processes of the fifth and sixth cervi- 
cal vertebrae. The vertical portion lies directly on the front of the spine; it arises, 
below, from the front of the bodies of the upper three dorsal and lower three cer- 
vical vertebra?, and is inserted above into the front of the bodies of the second, 
third, and fourth cervical vertebrae. 
Relations.-By its anterior surface, with the prevertebral fascia, the pharynx, 
the oesophagus, sympathetic nerve, the sheath of the great vessels of the neck, 
the inferior thyroid artery, and recurrent laryngeal nerve; by its posterior surface, 
with the cervical and dorsal portions of the spine. Its inner border is separated 
from the opposite muscle by a considerable interval below, but they approach 
each other above. 
8. The Lateral Vertebral Region (Figs. 279, 280). 
Scalenus anticus. Scalenus medius. Scalenus posticus. 
The Scalenus Anticus (m. scalenus anterior) is a conical-shaped muscle, 
situated deeply at the side of the neck, behind the Sterno-mastoid. It 
arises from the anterior tubercles of 
the transverse processes of the third, 
fourth, fifth, and sixth cervical verte- 
bra?, and, descending almost vertically, 
is inserted by a narrow, Hat tendon 
into the Scalene tubercle on the inner 
border and upper surface of the first 
rib. The lower part of this muscle sep- 
arates the subclavian artery and vein, 
the latter being in front, and the former, 
with the brachial plexus, behind. 
Relations.-In jront, with the clav- 
icle, the Subclavius, Sterno-mastoid, 
and Omo-hyoid muscles, the Trans- 
versalis colli, the suprascapular and 
ascending cervical arteries, the subcla- 
vian vein, and the phrenic nerve; by 
its posterior surjace, with the Scalenus 
medius, pleura, subclavian artery, and 
brachial plexus of nerves. It is sep- 
arated from the Longus colli, on the 
inner side, by the vertebral artery. 
On the anterior tubercles of the trans- 
verse processes of the cervical vertebrae, 
between the attachments of the Scale- 
nus anticus and Longus colli, lies the 
ascending cervical branch of the infe- 
rior thyroid artery. 
The Scalenus Medius, the largest and longest of the three Scaleni, arises from 
the posterior tubercles of the transverse processes of the lower six cervical vertebrae, 
-SUBCLAVIAN 
^ARTERY 
Fig. 280.-Scaleni muscles. (Poirier and Charpy.) THE LATERAL VERTEBRAL REGION 
409 
and, descending along the side of the vertebral column, is inserted by a broad 
attachment into the upper surface of the first rib, behind the groove for the sub- 
clavian artery, as far back as the tubercle. It is separated from the Scalenus 
anticus by the subclavian artery below and the cervical nerves above. The pos- 
terior thoracic, or nerve of Bell, is formed in the substance of the Scalenus medius 
and emerges from it. The nerve to the Rhomboids also pierces it. 
Relations.-By its anterior surface, with the Sterno-mastoid; it is crossed by 
the clavicle, the Omo-hyoid muscle, subclavian artery, and cervical nerves. To 
its outer side is the Levator anguli scapula? and the Scalenus posticus muscle. 
The Scalenus Posticus (m. scalenus posterior}, the smallest of the three Scaleni, 
arises, by two or three separate tendons, from the posterior tubercles of the trans- 
verse processes of the lower two or three cervical vertebrae, and, diminishing as it 
descends, is inserted by a thin tendon into the outer surface of the second rib, 
behind the attachment of the Serratus magnus. This is the most deeply placed of 
the three Scaleni, and is occasionally blended with the Scalenus medius. 
Nerves.-The Rectus capitis anticus major and minor and the Rectus lateralis 
are supplied by the first cervical nerve, and from the loop formed between it and 
the second; the Longus colli and Scaleni, by branches from the anterior divisions 
of the lower cervical nerves (fifth, sixth, seventh, and eighth) before they form the 
brachial plexus. The Scalenus medius also receives a filament from the deep 
external branches of the cervical plexus. 
Actions.-The Rectus anticus major and minor are the direct antagonists of the 
muscles at the back of the neck, serving to restore the head to its natural position 
after it has been drawn backward. These muscles also serve to flex the head, and, 
from their obliquity, rotate it, so as to turn the face to one or the other side. The 
Longus colli flexes and slightly rotates the cervical portion of the spine. The 
Scaleni muscles, when they take their fixed point from above, elevate the first and 
second ribs, and are, therefore, inspiratory muscles. When they take their fixed 
point from below, they bend the spinal column to one or the other side. If the 
muscles of both sides act, lateral movement is prevented, but the spine is slightly 
flexed. The Rectus lateralis, acting on one side, bends the head laterally. 
Surface Form.-The muscles in the neck, with the exception of the Platysma myoides, are 
invested by the deep cervical fascia, which softens down their form, and is of considerable 
importance in connection with deep cervical abscesses and tumors, modifying the direction of 
the growth of tumors and of the enlargement of abscesses, and causing them to extend 
laterally instead of toward the surface. The Platysma myoides does not influence surface 
form except when in action, when it produces wrinkling of the skin of the neck, which is 
thrown into oblique ridges parallel with the fasciculi of the muscle. Sometimes this con- 
traction takes place suddenly and repeatedly as a sort of spasmodic twitching, the result of 
a nervous habit. The Sterno-cleido-mastoid is the most important muscle of the neck as 
regards its surface form. If the muscle is put into action by drawing the chin downward and 
to the opposite shoulder, its surface form will be plainly outlined. The sternal origin will 
stand out as a sharply-defined ridge, while the clavicular origin will present a flatter and not so 
prominent an outline. The fleshy middle portion will appear as an oblique roll or elevation, 
with a thick rounded anterior border gradually becoming less marked above. On the opposite 
side-i. e., on the side to which the head is turned-the outline is lost, its place being occupied 
by an oblique groove in the integument. When the muscle is at rest its anterior border is still 
visible, forming an oblique rounded ridge, terminating below in the sharp outline of the sternal 
head. The posterior border of the muscle does not show above the clavicular head. The 
anterior border is defined by drawing a line from the tip of the mastoid process to the sterno- 
clavicular joint. It is an important surface-marking in the operation of ligature of the common 
carotid artery and in some other operations. Between the sternal and clavicular heads is a slight 
depression, most marked when the muscle is in action. This is bounded below by the prominent 
sternal extremity of the clavicle. Between the sternal origins of the two muscles is a V-shaped 
space, the suprasternal notch, more pronounced below, and becoming toned down above, where 
the Sterno-hyoid and Sterno-thyroid muscles, lying upon the trachea, become more prominent. 
Above the hyoid bone, in the middle line, the anterior belly of the Digastric to a certain extent 
influences surface form. It corresponds to a line drawn from the symphysis of the lower jaw to 410 
THE MUSCLES AND FASCIAE 
the side of the body of the hyoid bone, and renders this part of the hyo-mental region convex. 
In the posterior triangle of the neck, the posterior belly of the Omo-hyoid, when in action, forms 
a conspicuous object, especially in thin necks, presenting a cord-like form running across this 
region, almost parallel with, and a little above, the clavicle. 
MUSCLES AND FASCIA OF THE TRUNK. 
The muscles of the Trunk may be arranged in four groups, corresponding 
with the region in which they are situated. 
I. The Back. 
IL The Thorax. 
ITT. The Abdomen. 
IV. The Perinseum. 
I. MUSCLES OF THE BACK. 
The muscles of the Back are very numerous, and may be subdivided into five 
layers: 
First Layer. 
Trapezius. 
Latissimus dorsi. 
Second Layer. 
Levator anguli scapula;. 
Rhomboideus minor. 
Rhomboideus major. 
Third Layer. 
Serratus posticus superior. 
Serratus posticus inferior. 
Splenitis capitis. 
Splenius colli. 
Fourth Layer. 
Sacral and Lumbar Regions. 
Erector spinse. 
Dorsal Region. 
Ilio-costalis. 
Musculus accessorius ad ilio-costalem. 
Longissimus dorsi. 
Spinalis dorsi. 
Cervical Region. 
Cervicalis ascendens. 
Transversalis cervicis. 
Trachelo-mastoid. 
Complexus. 
Biventer cervicis. 
Spinalis colli. 
Fifth Layer. 
Semispinalis dorsi. 
Semispinalis colli. 
Multifidus spinae. 
Rotatores spinae. 
Supraspinales. 
Interspinales. 
Extensor coccygis. 
I ntertransversalis. 
Rectus capitis posticus major. 
Rectus capitis posticus minor. 
Obliquus capitis inferior. 
Obliquus capitis superior. 
The First Layer (Fig. 282). 
Trapezius. Latissimus dorsi. 
Dissection (Fig. 281).-Place the body in a prone position, with the arms extended over 
the sides of the table, and the chest and abdomen supported by several blocks, so as to render 
the muscles tense. Then make an incision along the middle line of the back from the occipital 
protuberance to the coccyx. Make a transverse incision from the upper end of this to the mas- 
toid process, and a third incision from its lower end, along the crest of the ilium to about its 
middle. This large intervening space should, for convenience of dissection, be subdivided by 
a fourth incision, extending obliquely from the spinous process of the last dorsal vertebra, upward 
and outward, to the acromion process. This incision corresponds with the lower border of the 
Trapezius muscle. The Haps of integument are then to be removed in the direction shown in 
the figure. OF THE BACK 
411 
Superficial Fascia.-The superficial fascia is exposed upon removing the skin 
from the back. It forms a layer of considerable thickness and strength, in which 
a quantity of granular pinkish fat is contained. It is continuous with the super- 
ficial fascia in other parts of the body. 
Deep Fascia.-The deep fascia is a dense fibrous layer attached to the 
occipital bone, the spines of the vertebrae, the crest of the ilium, and the spine 
of the scapula. It covers over the superficial 
muscles, forming sheaths for them, and in the 
neck forms the posterior part of the deep cer- 
vical fascia; in the thorax it is continuous with 
the deep fascia of the axilla and chest, and in 
the abdomen with that covering the abdominal 
muscles. In the back of the thoracic region 
the deep fascia is called the vertebral aponeurosis 
or the aponeurosis of the latissimus dorsi muscle. 
It covers the erector spime muscles, and is the 
posterior layer of the lumbar fascia. 
The Trapezius is a broad, flat, triangular 
muscle, placed immediately beneath the skin 
and fascia, and covering the upper and back 
part of the neck and shoulders. It arises from 
the external occipital protuberance and the 
inner third of the superior curved line of the 
occipital bone; from the ligamentum nuchie, the 
spinous process of the seventh cervical, and the 
spinous processes of all the dorsal vertebrae; and 
from the corresponding portion of the supra- 
spinous ligament. From this origin the supe- 
rior fibres proceed downward and outward, 
the inferior ones upward and outward, and 
the middle fibres horizontally, and are in- 
serted, the superior ones into the outer third of 
the posterior border of the clavicle; the middle 
fibres into the inner margin of the acromion 
process, and into the superior lip of the posterior border or crest of the spine 
of the scapula; the inferior fibres converge near the scapula, and terminate in a 
triangular aponeurosis, which glides over a smooth surface at the inner extremity 
of the spine, to be inserted into a tubercle at the outer part of this smooth surface. 
The Trapezius is fleshy in the greater part of its extent, but tendinous at its origin 
and insertion. At its occipital origin it is connected to the bone by a thin fibrous 
lamina, firmly adherent to the skin, and wanting the lustrous, shining appearance 
of aponeuroses. At its origin from the spines of the vertebrae it is connected to 
the bones by means of a broad semi-elliptical aponeurosis, which occupies the 
space between the sixth cervical and the third dorsal vertebrae, and forms, with 
the aponeurosis of the opposite muscle, a tendinous ellipse. The rest of the 
muscle arises by numerous short tendinous fibres. If the Trapezius is dissected 
on both sides, the two muscles resemble a trapezium or diamond-shaped quad- 
rangle; two angles corresponding to the shoulders; a third to the occipital pro- 
tuberance; and the fourth to the spinous process of the last dorsal vertebra. The 
clavicular insertion of this muscle varies as to the extent of its attachment; it 
sometimes advances as far as the middle of the clavicle, and may even become 
blended with the posterior edge of the Sterno-mastoid or overlap it. This should 
be borne in mind in the operation for tying the third part of the subclavian 
artery. 
Fig. 281.-Dissection of the muscles of 
the back. 412 
THE MUSCLES AND FASCHE 
Triangle 
of Petit. 
Fig. 282.-Muscles of the back. On the left side is exposed the first layer; on the right side, the second layer 
and part of the third. OF THE BACK 
413 
Relations.-By its superficial surface, with the integument; by its deep sur- 
face, in the neck, with the Complexus, Splenius, Levator anguli scapulae, and 
Rhomboideus minor; in the back, with the Rhomboideus major, Supraspinatus, 
Infraspinatus, and Vertebral aponeurosis (which separates it from the prolonga- 
tions of the Erector spinae), and the Latissimus dorsi. The spinal accessory nerve 
and the superficial cervical artery and branches from the third and fourth cervical 
nerves pass beneath the anterior border of this muscle. The anterior margin of its 
cervical portion forms the posterior boundary of the posterior triangle of the neck, 
the other boundaries being the Sterno-mastoid in front and the clavicle below. 
The Ligamentum nuchae (Fig. 282) is a fibrous membrane, which, in the neck, 
represents the supraspinous and interspinous ligaments of the lower vertebrae. 
It extends from the external occipital protuberance to the spinous process of the 
seventh cervical vertebra. From its anterior border a fibrous lamina (fascia 
nucha') is given off, which is attached to the external occipital crest, the posterior 
tubercle of the atlas, and the spinous process of each of the cervical vertebrae, so 
as to form a septum between the muscles on each side of the neck. In man it is 
merely the rudiment of an important elastic ligament, which, in some of the lower 
animals, serves to sustain the weight of the head. 
The Latissimus Dorsi is a broad flat muscle, which covers the lumbar and the 
lower half of the dorsal regions, and is gradually contracted into a narrow fascic- 
ulus at its insertion into the humerus. It arises by tendinous fibres from the 
spinous processes of the six inferior dorsal vertebrae and from the posterior layer 
of the lumbar fascia (see page 416), by which it is attached to the spines of the 
lumbar and sacral vertebrae and to the supraspinous ligament. It also arises 
from the external lip of the crest of the ilium, behind the origin of the External 
oblicjue, and by fleshy digitations from the three or four lower ribs, which are 
interposed between similar processes of the External oblique muscle (Fig. 289, 
page 434). From this extensive origin the fibres pass in different directions, the 
upper ones horizontally, the middle obliquely upward, and the lower vertically 
upward, so as to converge and form a thick fasciculus, which crosses the inferior 
angle of the scapula, and occasionally receives a few fibres of origin from it. The 
muscle then curves around the lower border of the Teres major, and is twisted 
upon itself so that the superior fibres become at first posterior and then inferior, 
and the vertical fibres at first anterior and then superior. It then terminates in a 
short quadrilateral tendon, about three inches in length, which, passing in front of 
the tendon of the Teres major, is inserted into the bottom of the bicipital groove 
of the humerus, its insertion extending higher on the humerus than that of the 
tendon of the Pectoralis major. The lower border of the tendon of this muscle is 
united with that of the Teres major, the surfaces of the two being separated by a 
bursa; another bursa is sometimes interposed between the muscle and the inferior 
angle of the scapula. This muscle at its insertion gives off an expansion to the 
deep fascia of the arm. 
A muscular slip, the axillary arch, varying from 3 to 4 inches in length, and from | to | of an 
inch in breadth, occasionally arises from the upper edge of the Latissimus dorsi about the mid- 
dle of the posterior fold of the axilla, and crosses the axilla in front of the axillary vessels and 
nerves, to join the under surface of the tendon of the Pectoralis major, the Coraco-byachialis, 
or the fascia over the Biceps. The position of this abnormal slip is a point of interest in its 
relation to the axillary artery, as it crosses the vessel just above the spot usually selected for the 
application of a ligature, and may mislead the surgeon during the operation. It may be easily 
recognized by the transverse direction of its fibres. Dr. Struther found it, in 8 out of 105 sub- 
jects, occurring seven times on both sides. In most subjects there is a fibrous axillary arch, 
in only a few is the arch muscular. 
There is usually a fibrous slip which passes from the lower border of the tendon of the Latis- 
simus dorsi, near its insertion, to the long head of the Triceps. This is occasionally muscular, 
and is the representative of the Dorso-epitrochlearis muscle of apes. 414 
THE MUSCLES AND FASCIA 
Relations.-Its superficial surjace is subcutaneous, excepting at its upper part, 
where it is covered by the 'Trapezius, and at its insertion, where its tendon is 
crossed by the axillary vessels and the brachial plexus of nerves. By its deep 
surjace it is in relation with the lumbar fascia, the Serratus posticus inferior, 
the lower External intercostal muscles and ribs, inferior angle of the scapula, 
Rhomboideus major, Infraspinatus, and Teres major. Its outer margin is sepa- 
rated below from the External oblique by a small triangular interval, the triangle 
of Petit (trigonum lumbale [Petiti]); and another triangular interval exists between 
its upper border and the margin of the Trapezius, in which the Rhomboideus 
major muscle is exposed. 
Nerves.-The Trapezius is supplied by the spinal accessory, and by branches 
from the anterior divisions of the third and fourth cervical nerves: the Latissimus 
dorsi, by the middle or long subscapular nerve. 
The Second Layer (Fig. 282). 
Levator anguli scapulae. 
Rhomboideus minor. 
Rhomboideus major. 
Dissection.-The Trapezius must be removed, in order to expose the next layer; to effect 
this, detach the muscle from its attachment to the clavicle and spine of the scapula, and turn 
it back toward the spine. 
The Levator Anguli Scapulae (m. levator scapulae) is situated at the back part 
and side of the neck. It arises by tendinous slips from the transverse process of 
the atlas, and from the posterior tubercles of the transverse processes of the second, 
third, and fourth cervical vertebrae; these, becoming fleshy, are united so as to 
form a flat muscle, which, passing downward and backward, is inserted into the 
posterior border of the scapula, between the superior angle and the triangular 
smooth surface at the root of the spine. 
Relations.-By its superficial surjace, with the integument, Trapezius, and 
Sterno-mastoid; by its deep surface, with the Splenius colli, Transversalis cervicis, 
Cervicalis ascendens, and Serratus posticus superior muscles, and with the pos- 
terior scapular artery and the nerve to the Rhomboids. 
The Rhomboideus Minor arises from the ligamentum nuchse and spinous 
processes of the seventh cervical and first dorsal vertebrae. Passing downward 
and outward, it is inserted into the margin of the triangular smooth surface at the 
root of the spine of the scapula. This small muscle is usually separated from the 
Rhomboideus major by a slight cellular interval. 
Relations.-By its superficial {posterior) surjace, with the Trapezius; by its deep 
(anterior) surjace, with the same structures as the Rhomboideus major. 
The Rhomboideus Major is situated immediately below the preceding, the 
adjacent margins of the two being occasionally united. It arises by tendinous 
fibres from the spinous processes of the four or five upper dorsal vertebrae and the 
supraspinous ligament, and is inserted into a narrow tendinous arch attached 
above to the lower part of the triangular surface at the root of the spine; below, 
to the inferior angle, the arch being connected to the border of the scapula by a 
thin membrane. When the arch extends, as it occasionally does, but a short 
distance, the muscular fibres are inserted into the scapula itself. 
Relations.-By its superficial (posterior) surjace, with the Latissimus dorsi; by 
its deep (anterior) surjace, with the Serratus posticus superior, posterior scapular 
artery, the vertebral aponeurosis which separates it from the prolongations from 
the Erector spime, the Intercostal muscles, and ribs. 
Nerves.-The Rhomboid muscles are supplied by branches from the anterior 
division of the fifth cervical nerve; the Levator anguli scapulae, by the anterior OF THE BACK 
415 
divisions of the third and fourth cervical nerves, and frequently by a branch from 
the nerve to the Rhomboids. 
Actions.-The movements effected by the preceding muscles are numerous, as 
may be conceived from their extensive attachment. The whole of the Trapezius 
when in action retracts the scapula and braces back the shoulder; if the head is 
fixed, the upper part of the Trapezius will elevate the point of the shoulder, as in 
supporting weights; when the lower fibres are brought into action, they assist 
in depressing the bone. The middle and lower fibres of the muscle rotate the 
scapula, causing elevation of the acromion process. If the shoulders are fixed, both 
Trapezii, acting together, will draw the head directly backward; or if only one 
acts the head is drawn to the corresponding side. The Latissimus dorsi, when it 
acts upon the humerus, depresses it, draws it backward, adducts, and at the same 
time rotates it inward. It is the muscle which is principally employed in giving a 
downward blow, as in felling a tree or in sabre practice. If the arm is fixed, the 
muscle may act in various ways upon the trunk; thus, it may raise the lower ribs 
and assist in forcible inspiration; or, if both arms are fixed, the two muscles may 
assist the Abdominal and great Pectoral muscles in suspending and drawing the 
whole trunk forward, as in climbing or walking on crutches. The Levator anguli 
scapulae raises the superior angle of the scapula, and by so doing depresses the 
point of the shoulder. It assists the Trapezius in bearing weights and in shrugging 
the shoulders. If the shoulder be fixed, the Levator anguli scapulae inclines the 
neck to the corresponding side and rotates it in the same direction. The Rhom- 
boid muscles carry the inferior angle backward and upward, thus producing a 
slight rotation of the scapula upon the side of the chest, the Rhomboideus major 
acting especially on the lower angle of the scapula through the tendinous arch by 
which it is inserted. The Rhomboid muscles, acting together with the middle and 
inferior fibres of the Trapezius, will draw the scapula directly backward toward 
the spine. 
The Third Layer. 
Serratus posticus superior. 
Splenius capitis. 
Splenius colli. 
Serratus posticus inferior. 
Splenius 
Dissection.-To bring into view the third layer of muscles, remove the whole of the second, 
together with the Latissimus dorsi, by cutting through the Levator anguli scapulae and Rhom- 
boid muscles near their origin, and reflecting them downward, and by dividing the Latissimus 
dorsi in the middle by a vertical incision carried from its upper to its lower part, and reflecting 
the two halves of the muscle. 
The Serratus Posticus Superior (m. serratus posterior superior") is a thin, flat, 
quadrilateral muscle situated at the upper and back part of the thorax. It arises 
by a thin and broad aponeurosis from the ligamentum nuchae, and from the spinous 
processes of the last cervical and two or three upper dorsal vertebrae and from the 
supraspinous ligament. Inclining downward and outward, it becomes muscular, 
and is inserted, by four fleshy digitations into the upper borders of the second, 
third, fourth, and fifth ribs, a little beyond their angles. 
Relations.-Bv its superficial surface, with the Trapezius, Rhomboidei, and 
Levator anguli scapulae; by its deep surface, with the Splenius and the vertebral 
aponeurosis, which separates it from the prolongations of the Erector spinae, and 
with the Intercostal muscles and ribs. 
The Serratus Posticus Inferior (m. serratus posterior inferior") (Fig. 282) is 
situated at the junction of the dorsal and lumbar regions; it is of an irregularly 
quadrilateral form, broader than the preceding, and separated from it by a consid- 
erable interval. It arises by a thin aponeurosis from the spinous processes of the 
last two dorsal and two or three upper lumbar vertebrae, and from the supra- THE MUSCLES AND FASCIAE 
416 
spinous ligaments. Passing obliquely upward and outward, it becomes fleshy, 
and divides into four flat digitations, which are inserted into the lower borders of 
the four lower ribs, a little beyond their angles. The thin aponeurosis of origin 
is intimately blended with the lumbar fascia. 
Relations.-By its superficial surface, with the Latissimus dorsi. By its deep 
surface, with the Erector spinse, ribs, and Intercostal muscles. Its upper margin 
is continuous with the vertebral aponeurosis. 
The vertebral aponeurosis is a thin, fibrous lamina, extending along the whole 
length of the back part of the thoracic region, serving to bind down the long 
Extensor muscles of the back which support the spine and head, and separate them 
from those muscles which connect the spine to the upper extremity. It consists of 
longitudinal and transverse fibres blended together, forming a thin lamella, which 
is attached in the median line to the spinous processes of the dorsal vertebrae; 
externally, to the angles of the ribs; and below, to the upper border of the Serratus 
posticus inferior and a portion of the lumbar fascia, which gives origin to the Latis- 
simus dorsi; above, it passes beneath the Serratus posticus superior and the Splenius, 
and blends with the deep fascia of the neck. 
The lumbar fascia or aponeurosis (Figs. 282 and 295), which may be regarded 
as the posterior aponeurosis of the Transversalis abdominis muscle, consists 
of three laminae, which are attached as follows: the posterior layer, to the 
spines of the lumbar and sacral vertebrae and their supraspinous ligaments; the 
middle layer, to the tips of the transverse processes of the lumbar vertebrae and 
their intertransverse ligaments; the anterior layer, to the roots of the lumbar 
transverse processes. The posterior layer is continued above as the vertebral 
aponeurosis, while inferiorly it is fixed to the outer lip of the iliac crest. With this 
layer are blended the aponeurotic origin of the Serratus posticus inferior and part 
of that of the Latissimus dorsi. The middle layer is attached above to the last 
rib, and below to the iliac crest; the anterior layer is fixed below to the ilio-lumbar 
ligament and iliac crest; while above it is thickened to form the external arcuate 
ligament of the Diaphragm, and stretches from the tip of the last rib to the trans- 
verse process of the first or second lumbar vertebra. These three layers, together 
with the vertebral column, enclose two spaces, the posterior of which is occupied 
by the Erector spime muscle, and the anterior by the Quadratus lumborum. 
Now detach the Serratus posticus superior from its origin, and turn it outward, when the 
Splenius muscle will be brought into view. 
The Splenius (Fig. 282) is situated at the back of the neck and upper part 
of the dorsal region. At its origin it is a single muscle, which soon after its 
origin becomes broad, and divides into two portions, which have separate inser- 
tions. It arises, by tendinous fibres, from the lower half of the ligamentum 
nuchte, from the spinous processes of the last cervical and of the six upper 
dorsal vertebrae, and from the supraspinous ligament. From this origin the fleshy 
fibres proceed obliquely upward and outward, forming a broad flat muscle, which 
divides as it ascends into two portions, the Splenius capitis and Splenius colli. 
The Splenius capitis (m. splenius capitis") is inserted into the mastoid process of 
the temporal bone, and into the rough surface on the occipital bone just beneath 
the superior curved line. 
The Splenius colli (m. splenius cervicis) is inserted, by tendinous fasciculi, into the 
posterior tubercles of the transverse processes of the two or three upper cervical 
vertebrae. 
The Splenius is separated from its fellow of the opposite side by a triangular 
interval, in which is seen the Complexus. 
Relations.-By its superficial surface, with the Trapezius, from which it is sepa- 
rated below by the Rhomboidei and the Serratus posticus superior. It is covered OF THE BACK 
417 
at its insertion by the Sterno-mastoid, and at the lower and back part of the neck 
by the Levator anguli scapulae; by its deep surjace, with the Spinalis dorsi, Longis- 
simus dorsi, Semispinalis colli, Complexus, Trachelo-mastoid, and Transversalis 
cervicis. 
Nerves.-The Splenius is supplied from the external branches of the posterior 
divisions of the cervical nerves; the Serratus posticus superior is supplied by the 
external branches of the posterior divisions of the upper dorsal nerves; the Ser- 
ratus posticus inferior by the external branches of the posterior divisions of the 
lower dorsal nerves. 
Actions.-The Serrati are respiratory muscles. The Serratus posticus supe- 
rior elevates the ribs; it is therefore an inspiratory muscle; while the Serratus 
inferior draws the lower ribs downward and backward, and thus elongates the 
thorax. It also fixes the lower ribs, thus aiding the downward action of the 
diaphragm and resisting the tendency which it has to draw the lower ribs upward 
and forward. It must therefore be regarded as a muscle of inspiration. This 
muscle is also probably a tensor of the vertebral aponeurosis. The Splenii muscles 
of the two sides, acting together, draw the head directly backward, assisting the 
Trapezius and Complexus; acting separately, they draw the head to one or the 
other side, and slightly rotate it, turning the face to the same side. They also 
assist in supporting the head in the erect position. 
The Fourth Layer (Fig. 283). 
I. Erector spinse. 
a. Outer Column. 
Ilio-costalis. 
Musculus accessorius. 
Cervicalis ascendens. 
b. Middle Column. 
Longissimus dorsi. 
Transversalis cervicis. 
Trachelo-mastoid. 
Spinalis dorsi. 
c. Inner Column. 
Spinalis colli. 
II. Complexus. 
Dissection.-To expose the muscles of the fourth layer, remove entirely the Serrati and the 
vertebral and lumbar fasciae. Then detach the Splenius by separating its attachment to the 
spinous processes and reflecting it outward. 
The Erector Spinae (m. sacrospinalis) and its prolongations in the dorsal 
and cervical regions fill up the vertebral groove on each side of the spine. It 
is covered in the lumbar region by the lumbar fascia; in the dorsal region, by 
the Serrati muscles and the vertebral aponeurosis; and in the cervical region, by 
a layer of cervical fascia continued beneath the Trapezius and the Splenius. This 
large muscular and tendinous mass varies in size and structure at different parts 
of the spine. In the sacral region the Erector spinae is narrow and pointed, and 
its origin chiefly tendinous in structure. In the lumbar region the muscle becomes 
enlarged, and forms a large fleshy mass. In the dorsal region it subdivides into 
two parts, which gradually diminish in size as they ascend to be inserted into the 
vertebrae and ribs. 
The Erector spinae arises from the anterior surface of a very broad and thick 
tendon, which is attached, internally, to the spines of the sacrum, to the spinous 
processes of the lumbar and the eleventh and twelfth dorsal vertebrae, and the 
supraspinous ligament; externally, to the back part of the inner lip of the crest of 
the ilium, and to the series of eminences on the posterior part of the sacrum, which 
represents the transverse processes, where it blends with the great sacro-sciatic and 
posterior sacro-iliac ligaments. Some of its fibres are continuous with the fibres 418 
THE MUSCLES AND EASCEE 
Occipital bone. 
MULTIFIDUS SPINXE. 
First dorsal vertebra.- 
1st rib. 
■2nd. 
\3rd. 
First lumbar vertebra. 
First sacral vertebra. 
Fig. 283.--Muscles of the back. Deep layers. OF THE BACK 
419 
of origin of the Gluteus maximus. The muscular fibres form a single large fleshy 
mass, bounded in front by the transverse processes of the lumbar vertebra? and by 
the middle lamella of the lumbar fascia. Opposite the last rib it divides into two 
parts, the Ilio-costalis and the Longissimus dorsi; the Spinalis dorsi is given off 
from the latter in the upper dorsal region. 
The Ilio-costalis or Sacro-lumbalis (m. iliocostalis lumborum), the external por- 
tion of the Erector spinae, is inserted, generally, by six or seven flattened tendons into 
the inferior borders of the angles of the six or seven lower ribs. The number of the 
tendons of this muscle is, however, very variable, and therefore the number of ribs 
into which it is inserted vary. Frequently it is found to possess nine or ten 
tendons, and sometimes as many tendons as there are ribs, and is then inserted 
into the angles of all the ribs. If this muscle is reflected outward, it will be 
seen to be reinforced by a series of muscular slips which arise from the angles 
of the ribs; by means of these the Ilio-costalis is continued upward to the upper 
ribs and cervical portion of the spine. The accessory portions form two additional 
muscles, the Musculus accessorius and the Cervicalis ascendens. 
The Musculus accessorius ad ilio-costalem (m. iliocostalis dorsi) arises, by separate 
flattened tendons, from the upper borders of the angles of the six lower ribs: these 
become muscular, and are finally inserted, by separate tendons, into the upper 
borders of the angles of the six upper ribs and into the back of the transverse 
processes of the seventh cervical vertebra. 
The Cervicalis ascendens1 (m. iliocostalis cervicis) is the continuation of the Acces- 
sorius upward into the neck; it is situated on the inner side of the tendons of the 
Accessorius, arising from the angles of the four or five upper ribs, and is inserted 
by a series of slender tendons into the posterior tubercles of the transverse processes 
of the fourth, fifth, and sixth cervical vertebrae. 
The Longissimus dorsi is the middle and largest portion of the Erector spinae. 
In the lumbar region, where it is as yet blended with the Ilio-costalis, some of the 
fibres are attached to the whole length of the posterior surface of the transverse 
processes and the accessory processes of the lumbar vertebrae, and to the middle 
layer of the lumbar fascia. In the dorsal region, the Longissimus dorsi is inserted, 
by long thin tendons, into the tips of the transverse processes of all the dorsal ver- 
tebrae, and into from seven to eleven of the lower ribs between their tubercles and 
angles. This muscle is continued upward to the cranium and cervical portion of 
the spine by means of two additional muscles, the Transversalis cervicis and 
Trachelo-mastoid. 
The Transversalis cervicis or Transversalis colli (m. longissimus cervicis), placed 
on the inner side of the Longissimus dorsi, arises by long thin tendons from the 
summits of the transverse processes of the six upper dorsal vertebrae, and is 
inserted by similar tendons into the posterior tubercles of the transverse pro- 
cesses of the cervical vertebrae, from the second to the sixth inclusive. 
The Trachelo-mastoid (m. longissimus capitis) lies on the inner side of the preced- 
ing, between it and the Com plexus muscle. It arises, by tendons, from the trans- 
verse processes of the five or six upper dorsal vertebrae, and the articular processes 
of the three or four lower cervical. The fibres form a small muscle, which ascends 
to be inserted into the posterior margin of the mastoid process, beneath the Splenius 
and Sterno-mastoid muscles. This small muscle is almost always crossed by a 
tendinous intersection near its insertion into the mastoid process.2 
The Spinalis dorsi connects the spinous processes of the upper lumbar and the 
dorsal vertebrae together by a series of muscular and tendinous slips which are 
1 This muscle is sometimes called "Cervicalis descendens." The student should remember that these long 
muscles take their fixed point from above or from below, according to circumstances. 
2 These two muscles (Transversalis cervicis and Trachelo-mastoid) are sometimes described as one, having 
a common origin, but dividing above at their insertion. The Trachelo-mastoid is then termed the Transver- 
salis capitis. 420 
THE MUSCLES AND FASCIAE 
intimately blended with the Longissimus dorsi. It is situated at the inner side 
of the Longissimus dorsi, arising, by three or four tendons, from the spinous 
processes of the first two lumbar and the last two dorsal vertebrae: these, 
uniting, form a small muscle, which is inserted, by separate tendons, into spinous 
processes of the dorsal vertebra:, the number varying from four to eight. It is 
intimately united with the Semispinalis dorsi, which lies beneath it. 
The Spinalis colli (m. spinalis cervicis) is a small muscle, connecting together the 
spinous processes of the cervical vertebrae, and analogous to the Spinalis dorsi in 
the dorsal region. It varies considerably in its size and in its extent of attachment 
to the vertebrae, not only in different bodies, but on the two sides of the same body. 
It usually arises by fleshy or tendinous slips, varying from two to four in number, 
from the spinous processes of the fifth, sixth, and seventh cervical vertebrae, and 
occasionally from the first and second dorsal, and is inserted into the spinous 
process of the axis, and occasionally into the spinous processes of the two vertebrae 
below it. This muscle was found absent in five cases out of twenty-four. 
Relations.-The Erector spime and its prolongations are bound down to the 
vertebrae and ribs in the lumbar and dorsal regions by the lumbar fascia and 
the vertebral aponeurosis. The inner part of these muscles covers the muscles 
of the fifth layer. In the neck they are in relation, by their superficial surjace, with 
the Trapezius and Splenius; by their deep surjace, with the Semispinalis dorsi et 
colli and the Recti and Obliqui. 
The Complexus (m. semispinalis capitis) is a broad thick muscle, situated at the 
upper and back part of the neck, beneath the Splenius, and internal to the Trans- 
versalis cervicis and Trachelo-mastoid. It arises, by a series of tendons, from 
the tips of the transverse processes of the upper six or seven dorsal and the last 
cervical vertebrae, and from the articular processes of the three cervical above 
this. The tendons, uniting, form a broad muscle, which passes obliquely upward 
and inward, and is inserted into the innermost depression between the two curved 
lines of the occipital bone. This muscle, about its middle, is traversed by a trans- 
verse tendinous intersection. The biventer cervicis is a small fasciculus, situated 
on the inner side of the preceding, and in the majority of cases blended with it; 
it has received its name from having a tendon intervening between two fleshy 
bellies. It is sometimes described as a part of the Complexus. It arises by from 
two to four tendinous slips, from the transverse processes of as many of the upper 
dorsal vertebrae, and is inserted, on the inner side of the Complexus, into the supe- 
rior curved line of the occipital bone. 
Relations.-The Complexus is covered by the Splenius and the Trapezius. It 
lies on the Rectus capitis posticus major and minor, the Obliquus capitis superior 
and inferior, and on the Semispinalis colli, from which it is separated by the pro- 
funda cervicis artery, the princeps cervicis artery, and branches of the posterior 
primary divisions of the cervical nerves. The Biventer cervicis is separated from 
its fellow of the opposite side by the ligamentum nuchae. 
The Fifth Layer (Fig. 283). 
Semispinalis dorsi. 
Semispinalis colli. 
Multifidus spime. 
Rotatores spinae. 
Supraspinales. 
Interspinales. 
Extensor coccygis. 
Intertransversales. 
Rectus capitis posticus major. 
Rectus capitis posticus minor. 
Obliquus capitis inferior. 
Obliquus capitis superior. 
Dissection.-Remove the muscles of the preceding layer by dividing and turning aside the 
Complexus; then detach the Spinalis and Longissimus dorsi from their attachments, divide the 
Erector spinse at its connection below to the sacral and lumbar spines and turn it outward. The 
muscles filling up the interval between the spinous and transverse processes are then exposed. OF THE BACK 
The Semispinalis Dorsi consists of thin, narrow, fleshy fasciculi interposed 
between tendons of considerable length. It arises by a series of small tendons 
from the transverse processes of the lower dorsal vertebrae, from the tenth or 
eleventh to the fifth or sixth; and is inserted, by five or six tendons, into the 
spinous processes of the upper four dorsal and lower two cervical vertebrae. 
The Semispinalis Colli {m. semispinalis cervicis), thicker than the preceding, 
arises by a series of tendinous and fleshy fibres from the transverse processes of 
the upper five or six dorsal vertebrae, and is inserted into the spinous processes of 
four cervical vertebrae, from the axis to the fifth cervical. The fasciculus con- 
nected with the axis is the largest, and chiefly muscular in structure. 
Relations.-By their superficial surjace, from below upward, with the Spinalis 
dorsi, Longissimus dorsi, Splenius, Complexus, the profunda cervicis artery, the 
princeps cervicis artery, and the internal branches of the posterior divisions of 
the first, second, and third cervical nerves; by their deep surjace, with the Mul- 
tifidus spinae. 
The Multifidus Spinae (m. multifidus) consists of a number of fleshy and ten- 
dinous fasciculi which fill up the groove on either side of the spinous processes of the 
vertebrae, from the sacrum to the axis. In the sacral region these fasciculi arise from 
the back of the sacrum, as low as the fourth sacral foramen, and from the aponeu- 
rosis of origin of the Erector spinae; from the inner surface of the posterior superior 
spine of the ilium and posterior sacro-iliac ligaments; in the lumbar regions, from 
the articular processes; in the dorsal region, from the transverse processes; and in 
the cervical region, from the articular processes of the three or four lower vertebrae. 
Each fasciculus, passing obliquely upward and inward, is inserted into the whole 
length of the spinous process of one of the vertebrae above. These fasciculi vary 
in length: the most superficial, the longest, pass from one vertebra to the third or 
fourth above; those next in order pass from one vertebra to the second or third 
above; whilst the deepest connect two contiguous vertebrae. 
Relations.-By its superficial surjace, with the Longissimus dorsi, Spinalis dorsi, 
Semispinalis dorsi, and Semispinalis colli; by its deep surjace, with the laminae 
and spinous processes of the vertebrae, and with the Rotatores spinae in the dorsal 
region. 
The Rotatores Spinae (mm. rotatores) are found only in the dorsal region of the 
spine, beneath the Multifidus spinae; they are eleven in number on each side. Each 
muscle is small and somewhat quadrilateral in form; it arises from the upper and 
back part of the transverse process, and is inserted into the lower border and outer 
surface of the lamina of the vertebra above, the fibres extending as far inward as 
the root of the spinous process. The first is found between the first and second 
dorsal; the last, between the eleventh and twelfth. Sometimes the number of these 
muscles is diminished by the absence of one or more from the upper or lower end. 
The Supraspinales consist of a series of fleshy bands which lie on the spinous 
processes in the cervical region of the spine. 
The Interspinales are short muscular fasciculi, placed in pairs between the 
spinous processes of the contiguous vertebrae, one on each side of the interspinous 
ligament. In the cervical region they are most distinct, and consist of six pairs, 
the first being situated between the axis and third vertebra, and the last between 
the last cervical and the first dorsal. They are small narrow bundles, attached, 
above and below, to the apices of the spinous processes. In the dorsal region 
they are found between the first and second vertebrae, and occasionally between 
the second and third; and below, between the eleventh and twelfth. In the 
lumbar region there are four pairs of these muscles in the intervals between the 
five lumbar vertebrae. There is also occasionally one in the interspinous space, 
between the last dorsal and first lumbar, and between the fifth lumbar and the 
sacrum. 
421 422 
THE MUSCLES AND FASCIAE 
The Extensor Coccygis is a slender muscular fasciculus, occasionally present, 
which extends over the lower part of the posterior surface of the sacrum and 
coccyx. It arises by tendinous fibres from the last bone of the sacrum or first 
piece of the coccyx, and passes downward to be inserted into the lower part of 
the coccyx. It is a rudiment of the Extensor muscle of the caudal vertebrae of 
the lower animals. 
The Intertransversales (mm. intertransversarii) are small muscles placed 
between the transverse processes of the vertebrae. I n the cervical region they are 
most developed, consisting of rounded muscular and tendinous fasciculi, which are 
placed in pairs, passing between the anterior and the posterior tubercles of the 
transverse processes of two contiguous vertebrae, separated from one another by 
the anterior division of the cervical nerve, which lies in the groove between them. 
In this region there are seven pairs of these muscles, the first pair being between 
the atlas and axis, and the last pair between the seventh cervical and first dorsal 
vertebrae. In the dorsal region they are least developed, consisting chiefly of 
rounded tendinous cords in the intertrans verse spaces of the upper dorsal vertebrae; 
but between the transverse processes of the lower three dorsal vertebrae, and 
between the transverse processes of the last dorsal and the first lumbar, they are 
muscular in structure. In the lumbar region they are arranged in pairs, on either 
side of the spine, one set occupying the entire interspace between the transverse 
processes of the lumbar vertebrae, the intertransversales laterales (mm. intertrans- 
versarii laterales); the other set, intertransversales mediales (mm. intertransversarii 
mediales), passing from the accessory process of one vertebra to the mammillary 
process of the next. 
The Rectus Capitis Posticus Major (m. rectus capitis posterior major) arises by 
a pointed tendinous origin from the spinous process of the axis, and, becoming 
broader as it ascends, is inserted into the inferior curved line of the occipital bone 
and the surface of bone immediately below it. As the muscles of the two sides pass 
upward and outward, they leave between them a triangular space, in which are 
seen the Recti capitis postici minores muscles. 
Relations.-By its superficial surface, with the Complexus, and, at its insertion, 
with the Superior oblique; by its deep surface, with part of the Rectus capitis 
posticus minor, the posterior arch of the atlas, the posterior occipito-atlantal liga- 
ment, and part of the occipital bone. 
The Rectus Capitis Posticus Minor (m. rectus capitis posterior minor), the small- 
est of the four muscles in this region, is of a triangular shape; it arises by a narrow 
pointed tendon from the tubercle on the posterior arch of the atlas, and, becom- 
ing broader as it ascends, is inserted into the rough surface beneath the inferior 
curved line, nearly as far as the foramen magnum, nearer to the middle line than 
the preceding. 
Relations.-By its superficial surface, with the Complexus and the Rectus capitis 
posticus major; by its deep surface, with the posterior occipito-atlantal ligament. 
The Obliquus Capitis Inferior, the larger of the two Oblique muscles, arises 
from the apex of the spinous process of the axis, and passes outward and slightly 
upward, to be inserted into the lower and back part of the transverse process of 
the atlas. 
Relations.-By its superficial surface, with the Complexus and with the pos- 
terior division of the second cervical nerve, which crosses it; by its deep surface, 
with the vertebral artery and posterior atlanto-axial ligament. 
The Obliquus Capitis Superior, narrow below, wide and expanded above, 
arises by tendinous fibres from the upper surface of the transverse process of the 
atlas, joining with the insertion of the preceding, and, passing obliquely upwrard 
and inward, is inserted into the occipital bone, between the two curved lines, 
external to the Complexus. OF THE BACK 
423 
Relations.-By its superficial surjace, with the Complexus and Trachelo-mastoid 
and occipital artery. By its deep surjace, with the posterior occipito-atlantal ligament. 
Between the two oblique muscles and the Rectus capitis posticus major a trian- 
gular interval exists, the suboccipital triangle. This triangle is bounded, above 
and internally, by the Rectus capitis posticus major; above and externally, by the 
Obliquus capitis superior; below and externally, by the Obliquus capitis inferior. 
It is covered in by a layer of dense fibro-fatty tissue, situated beneath the Com- 
plexus muscle. The floor is formed by the posterior occipito-atlantal ligament 
and the posterior arch of the atlas. It contains the vertebral artery, as it runs in 
a deep groove on the upper surface of the posterior arch of the atlas, and the pos- 
terior division of the suboccipital nerve. 
Nerves.-The third, fourth, and fifth layers of the muscles of the back are 
supplied by the posterior primary divisions of the spinal nerves. 
Actions.-When both the Spinales dorsi contract, they extend the dorsal region 
of the spine; when only one muscle contracts, it helps to bend the dorsal por- 
tion of the spine to one side. The Erector spime, comprising the Ilio-costalis and 
the Longissimus dorsi with their accessory muscles, serves, as its name implies, 
to maintain the spine in the erect posture; it also serves to bend the trunk back- 
ward when it is required to counterbalance the influence of any weight at the 
front of the body, as, for instance, when a heavy weight is suspended from the 
neck, or when there is any great abdominal distention, as in pregnancy or dropsy; 
the peculiar gait under such circumstances depends upon the spine being drawn 
backward by the counterbalancing action of the Erector spinae muscles. The 
muscles which form the continuation of the Erector spinae upward steady the 
head and neck, and fix them in the upright position. If the Ilio-costalis and 
Longissimus dorsi of one side act, they serve to draw down the chest and spine to 
the corresponding side. The Cervicales ascendens, taking their fixed points from 
the cervical vertebrae, elevate those ribs to which they are attached; taking their 
fixed points from the ribs, both muscles help to extend the neck; while one muscle 
bends the neck to its own side. The Transversalis cervicis, when both muscles act, 
taking their fixed point from below, bend the neck backward. The Trachelo- 
mastoid, when both muscles act, taking their fixed point from below, bend the head 
backward; while, if only one muscle acts, the face is turned to the side on which 
the muscle is acting, and then the head is bent to the shoulder. The two Recti 
muscles draw the head backward. The Rectus capitis posticus major, owing to 
its obliquity, rotates the cranium, with the atlas, round the odontoid process, 
turning the face to the same side. The Multifidus spime acts successively upon the 
different parts of the spine; thus, the sacrum furnishes a fixed point from which 
the fasciculi of this muscle act upon the lumbar region; these then become the 
fixed points for the fasciculi moving the dorsal region, and so on throughout the 
entire length of the spine; it is by the successive contraction and relaxation of 
the separate fasciculi of this and other muscles that the spine preserves the erect 
posture without the fatigue that would necessarily have been produced had this 
position been maintained by the action of a single muscle. The Multifidus spinae, 
besides preserving the erect position of the spine, serves to rotate it, so that the 
front of the trunk is turned to the side opposite to that from which the muscle 
acts, this muscle being assisted in its action by the Obliquus externus abdominis. 
The Complexi draw the head directly backward: if one muscle acts, it draws 
the head to one side, and rotates it so that the face is turned to the opposite 
side. The Superior oblique draws the head backward, and, from the obliquity 
in the direction of its fibres, will slightly rotate the cranium, turning the face to 
the opposite side. The Obliquus capitis inferior rotates the atlas, and with it the 
cranium, round the odontoid process, turning the face to the same side. The 
Semispinales, when the muscles of the two sides act together, help to extend the 424 
THE MUSCLES AND FASCIAE 
spine; when the muscles of one side only act, they rotate the dorsal and cervical 
parts of the spine, turning the body to the opposite side. The Supraspinales and 
Interspinales by approximating the spinous processes help to extend the spine. 
The Intertransversales approximate the transverse processes, and help to bend the 
spine to one side. The Rotatores spinae assist the Multifidus spinae to rotate the 
spine, so that the front of the trunk is turned to the side opposite to that from 
which the muscle acts. 
Surface Forms.-The surface forms produced by the muscles of the back are numerous and 
difficult to analyze unless they are considered in systematic order. The most superficial layer, 
consisting of large strata of muscular substance, influences to a certain extent the surface form, 
and at the same time reveals the forms of the layers beneath. The Trapezius at the upper part 
of the back, and in the neck, covers over and softens down the outline of the underlying muscles. 
Its anterior border forms the posterior boundary of the posterior triangle of the neck. It forms 
a slight undulating ridge which passes downward and forward from the occiput to the junction 
of the middle and outer third of the clavicle. The tendinous ellipse formed by a part of the 
origin of the two muscles at the back of the neck is always to be seen as an oval depression, 
more marked when the muscle is in action. A slight dimple on the skin opposite the interval 
between the spinous processes of the third and fourth dorsal vertebrse marks the triangular 
aponeurosis by which the inferior fibres are inserted into the root of the spine of the scapula. 
From this point the inferior border of the muscle may be traced as an undulating ridge to the 
spinous process of the twelfth dorsal vertebra. In like manner the Latissimus dorsi softens 
down and modulates the underlying structures at the lower part of the back and lower part of 
the side of the chest. In this way it modulates the outline of the Erector spinae; of the Serratus 
posticus inferior, which is sometimes to be discerned through it, and is sometimes entirely 
obscured by it; of part of the Serratus magnus and Superior oblique, which it covers; and of 
the convex oblique ridges formed by the ribs with the intervening intercostal spaces. The 
anterior border of the muscle is the only part which gives a distinct surface form. This border 
may be traced, when the muscle is in action, as a rounded edge, starting from the crest of the 
ilium, and passing obliquely forward and upward to the posterior border of the axilla, where it 
combines with the Teres major in forming a thick rounded fold, the posterior boundary of the 
axillary space. The muscles in the second layer influence to a very considerable extent the sur- 
face form of the back of the neck and upper part of the trunk. The Levator anguli scapulae 
reveals itself as a prominent divergent line, running downward and outward, from the trans- 
verse processes of the upper cervical vertebrae to the angle of the scapula, covered over and 
toned down by the overlying Trapezius. The Rhomboidei produce, when in action, a vertical 
eminence between the vertebral border of the scapula and the spinal furrow, varying in intensity 
according to the condition of contraction or relaxation of the Trapezius muscle, by which they 
are for the most part covered. The lowermost part of the Rhomboideus major is uncovered 
by the Trapezius, and forms on the surface an oblique ridge running upward and inward from 
the inferior angle of the scapula. Of the muscles of the third layer of the back, the Serratus 
posticus superior does not in any way influence surface form. The Serratus posticus inferior, 
when in strong action, may occasionally be revealed as an elevation beneath the Latissimus 
dorsi. The Splenii by their divergence serve to broaden out the upper part of the back of the 
neck and produce a local fulness in this situation, but do not otherwise influence surface form. 
Beneath all these muscles those of the fourth layer-the Erector spinoe and its continuations- 
influence the surface form in a decided manner. In the loins, the Erector spinae, bound down 
by the lumbar fascia, forms a rounded vertical eminence, which determines the depth of the 
spinal furrow, and which below tapers to a point on the posterior surface of the sacrum and 
becomes lost there. In the back it forms a flattened plane which gradually becomes lost. In 
the neck the only part of this group of muscles which influences surface form is the Trachelo- 
mastoid, which produces a short convergent line across the upper part of the posterior triangle 
of the neck, appearing from under cover of the posterior border of the Sterno-mastoid and 
being lost below beneath the Trapezius. 
The muscles belonging exclusively to this region are few in number. They are the 
II. MUSCLES AND FASCIA OF THE THORAX. 
Intercostales externi. 
Intercostales interni. 
Infracostales. 
Triangularis sterni. 
Levatores costarum. 
Diaphragm. 
Intercostal Fascia.-A thin but firm layer of fascia covers the outer surface of 
the External intercostal and the inner surface of the Internal intercostal muscles; OF THE THORAX 
425 
and a third layer, more delicate, is interposed between the two planes of muscular 
fibres. These are the intercostal fasciae, external, middle, and internal; they are best 
marked in those situations where the muscular fibres are deficient, as between the 
External intercostal muscles and sternum, in front, and between the Internal 
intercostals and spine, behind. 
The Intercostal Muscles (Figs. 291 and 315) are two thin planes of muscular 
and tendinous fibres, placed one over the other, filling up the intercostal spaces, 
and being directed obliquely between the margins of the adjacent ribs. They 
have received the name external and internal from the position they bear to one 
another. The tendinous fibres are longer and more numerous than the muscular; 
hence the walls of the intercostal spaces possess very considerable strength, to 
which the crossing of the muscular fibres materially contributes. 
The External Intercostals (mm. intercostales externi) are eleven in number on 
each side. They extend from the tubercles of the ribs, behind, to the commence- 
ment of the cartilages of the ribs, in front, where they terminate in a thin mem- 
brane, the anterior intercostal membrane, which is continued forward to the sternum. 
They arise from the lower border of the rib above, and are inserted into the upper 
border of the rib below. In the two lowest spaces they extend to the ends of the 
cartilages, and in the upper two or three spaces they do not quite extend to the ends 
of the ribs. Their fibres are directed obliquely downward and forward, in a 
similar direction with those of the External oblique muscle of the abdomen. 
They are thicker than the Internal intercostals. 
Relations.-By their order surface, with the muscles which immediately invest 
the chest-viz., the Pectoralis major and minor, Serratus magnus, and Rhom- 
boideus major, Serratus posticus superior and inferior, Scalenus posticus, Ilio- 
costalis, Longissimus dorsi, Cervicalis ascendens, Transversalis cervicis, Leva- 
tores costarum, Obliquus externus abdominis, and the Latissimus dorsi; by their 
internal surface, with the middle intercostal fascia, which separates them from the 
intercostal vessels and nerve and the Internal intercostal muscles, and, behind, 
from the pleura. 
The Internal Intercostals (mm. intercostales interni) are also eleven in number on 
each side. They commence anteriorly at the sternum in the interspaces between 
the cartilages of the true ribs, and from the anterior extremities of the cartilages 
of the false ribs, and extend backward as far as the angles of the ribs, whence they 
are continued to the vertebral column by a thin aponeurosis, the posterior inter- 
costal membrane. They arise from the ridge on the inner surface of the rib above, 
as well as from the corresponding costal cartilage, and are inserted into the upper 
border of the rib below. Their fibres are directed obliquely downward and back- 
ward, passing in the opposite direction to the fibres of the External intercostal 
muscle. 
Relations.-By their external surface, with the intercostal vessels and nerves 
and the External intercostal muscles; near the sternum, with the anterior inter- 
costal membrane and the Pectoralis major. By their internal surface, with the 
pleura costalis, Triangularis sterni, and Diaphragm. 
The Infracostales (mm. subcostales) consist of muscular and aponeurotic fas- 
ciculi, which vary in number and length; they are placed on the inner surface of the 
ribs, where the Internal intercostal muscles cease; they arise from the inner sur- 
face of one rib, and are inserted into the inner surface of the first, second, or third 
rib below. Their direction is most usually oblique, like the Internal intercostals. 
They are most frequent between the lower ribs. 
The Triangularis Sterni (m. transversus thoracis) (Fig. 284) is a thin plane of 
muscular and tendinous fibres, situated upon the inner wall of the front of the chest. 
It arises from the lower third of the posterior surface of the sternum, from the 
posterior surface of the ensiform cartilage, and from the sternal ends of the costal 426 
THE MUSCLES AND FASCIAE 
cartilages of the three or four lower true ribs. Its fibres diverge upward and out- 
ward, to be inserted by digitations into the lower borders and inner surfaces of the 
costal cartilages of the second, third, fourth, fifth, and sixth ribs. The lowest 
fibres of this muscle are horizontal in their direction, and are continuous with 
those of the Transversalis; those which succeed are oblique, whilst the superior 
fibres are almost vertical. This muscle varies much in its attachment, not only in 
different bodies, but on opposite sides of the same body. 
Relations.-In front, with the sternum, ensiform cartilage, costal cartilages, 
Internal intercostal muscles, and internal mammary vessels; behind, with the 
pleura, pericardium, and anterior mediastinum. 
STERNO-MASTOID. 
STERNO-MASTOID. 
STERNO- 
HYOID. 
SUBCLAVIUS. 
SU BCLAVIUS. 
Internal mam- 
mary artery. 
TRIANGULARIS 
STERNI. 
TR A N SV E RSA LIS ABDOMINIS. 
Fig. 284.-Posterior surface of sternum and costal cartilages, showing Triangularis sterni muscle. (From a 
preparation in the Museum of the Royal College of Surgeons of England.) 
The Levatores Costarum (Fig. 283), twelve in number on each side, are small 
tendinous and fleshy bundles which arise from the extremities of the transverse 
processes of the seventh cervical and eleven upper dorsal vertebrae, and, passing 
obliquely downward and outward, are inserted into the upper border of the rib 
below them, between the tubercle and the angle. The Inferior levatores divide 
into two fasciculi, one of which is inserted as above described; the other fasciculus 
passes down to the second rib below its origin; thus, each of the lower ribs receives 
fibres from the transverse processes of two vertebrae. 
Nerves.-The muscles of this group are supplied by the intercostal nerves. OF THE THORAX 
427 
The Diaphragm (diaphragma, from 8id<ppappa, a partition wall) (Figs. 285, 286, 
and 287) is a thin, musculo-fibrous septum, consisting of muscular fibres externally, 
which arise from the circumference of the thoracic cavity and pass upward and 
inward to converge to a central tendon. It is placed obliquely at the junction of 
the upper with the middle third of the trunk, and separates the thorax from the 
abdomen, forming the floor of the former cavity and the roof of the latter. It is 
elliptical, its longest diameter being from side to side; is somewhat fan-shaped, the 
broad elliptical portion being horizontal, the narrow part, the crura, which repre- 
sents the handle of the fan, vertical, and joined at right angles to the former. It 
is from this circumstance that some anatomists describe it as consisting of two 
portions, the upper or great muscle of the Diaphragm, and the lower or lesser 
muscle* It arises from the whole of the internal circumference of the thorax, 
being attached, in front, by fleshy fibres to the ensiform cartilage, sternal portion 
of the Diaphragm {pars sternalisy, on either side, to the inner surface of the 
cartilages and bony portions of the six or seven inferior ribs, costal portion (pars 
costalis), interdigitating with the Transversalis; and behind, to two aponeurotic 
arches, named the ligamentum arcuatum externum and the ligamentum arcuatum 
internum, and by the crura, to the lumbar vertebrae, lumbar portion (pars lumbalis). 
The fibres from these sources vary in length: those arising from the ensiform 
appendix are very short and occasionally aponeurotic; those from the ligamenta 
arcuata, and more especially those from the cartilages of the ribs at the side 
of the chest, are longer, describe well-marked curves as they ascend, and finally 
converge to be inserted into the circumference of the central tendon. Between 
the sides of the muscular slip from the ensiform appendix and the cartilages of 
the adjoining ribs the fibres of the Diaphragm are deficient, the interval being 
filled by areolar tissue, covered on the thoracic side by the pleurae; on the abdom- 
inal, by the peritoneum. This is, consequently, a weak point, and a portion of 
the contents of the abdomen may protrude through it into the chest, forming a 
phrenic or diaphragmatic hernia, or a collection of pus in the mediastinum may 
descend through it, so as to point at the epigastrium. A triangular gap is some- 
times seen between the fibres springing from the internal and those arising from 
the external arcuate ligament. When it exists, the kidney is separated from the 
pleura only by fatty and areolar tissue. 
A congenital deficiency in the Diaphragm may produce diaphragmatic hernia; 
in deficiency of the central tendon the hernia passes into the pericardial sac; in 
deficiency of one of the lateral portions the hernia passes into the pleural sac. 
There are five arcuate ligaments, two internal, two external, and one middle. 
The Ligamentum Arcuatum Internum (arcus lumbocostalis medialis) is a tendinous 
arch, thrown across the upper part of the Psoas magnus muscle, on each side of 
the spine. It is connected, by one end, to the outer side of the body of the first or 
second lumbar vertebra, being continuous with the outer side of the tendon of 
the corresponding crus; and, by the other end, to the front of the transverse process 
of the first, and sometimes also to that of the second, lumbar vertebra. 
The Ligamentum Arcuatum Externum (arcus lumbocostalis lateralis) is the thick- 
ened upper margin of the anterior lamella of the lumbar fascia; it arches across 
the upper part of the Quadratus lumborum, being attached, by one extremity, to 
the front of the transverse process of the first lumbar vertebra, and, by the other, 
to the apex and lower margin of the last rib. 
The arch of fibrous tissue which connects the crura of the diaphragm in front 
of the aorta is sometimes called the middle arcuate ligament. The Diaphragm is 
connected to the spine by two crura or pillars, which are situated on the bodies of 
lumbar vertebrae, on each side of the aorta. The crura, at their origin, are ten- 
dinous in structure; the right crus, larger and longer than the left, arising from 
the anterior common ligament and intervertebral substances of the three or four THE MUSCLES AND FASCIAE 
428 
upper lumbar vertebrae; the left, from the two upper lumbar vertebrae. These 
tendinous portions of the crura pass forward and inward, and gradually con- 
(ESOPHAGUS 
FORAMEN QUADRATUM 
FOR VENA CAVA 
CENTRAL TENDON, 
LEFT SIDE 
AORTA 
CENTRAL TENDON, 
RIGHT SIDE 
Fig. 285.-The Diaphragm, seen from above. (Poirier and Charpy.) 
Fig. 286.-The Diaphragm, viewed from in front. (Testut.) 
verge to meet in the middle line, forming an arch, beneath which passes the 
aorta, vena azygos major, and thoracic duct. From this tendinous arch muscular 
fibres arise, which diverge, the outermost portion being directed upward and OF THE THORAX 
429 
outward to the central tendon; the innermost decussating in front of the aorta 
and then diverging, so as to surround the oesophagus before ending in the central 
tendon. The fibres derived from the right crus are the most numerous and pass 
in front of those derived from the left. His and Spalteholz teach that three crura 
exist on each side-viz., the crus mediale, arising from the third and fourth lumbar 
vertebrae; the crus intermedium, from the second and third lumbar vertebrae; and 
the crus laterale, from the second or first lumbar vertebrae, and from the band of 
fascia which is stretched between the lateral part of the body of the first lumbar 
vertebra and the transverse process of the second lumbar vertebra in front of the 
Psoas muscle. 
The Central or Cordiform Tendon of the Diaphragm (centrum tendineum) is a thin 
but strong tendinous aponeurosis, situated at the centre of the vault formed by 
the muscle, immediately below the pericardium, with which it is partly blended. 
It is shaped somewhat like a trefoil leaf, consisting of three divisions, or leaflets. 
Fig. 287.-The Diaphragm, viewed from below. (Testut.) 
separated from one another by slight indentations. The right leaflet is the largest; 
the middle one, directed toward the ensiform cartilage, the next in size; and the 
left, the smallest. In structure, the tendon is composed of several planes of fibres 
which intersect one another at various angles, and unite into straight or curved 
bundles--an arrangement which affords it additional strength. 
The Openings.-The openings connected with the Diaphragm are three large 
and several smaller apertures. The former are the aortic, the oesophageal, and the 
opening for the vena cava. 
The Aortic Opening (hiatus aorticus) is the lowest and the most posterior of the 
three large apertures connected with this muscle, being at the level of the first 
lumbar vertebra. It is situated slightly to the left of the middle line, immediately 
in front of the bodies of the vertebrae; and is, therefore, behind the Diaphragm, not 
in it. It is an osseo-aponeurotic aperture, formed by a tendinous arch thrown 
across the front of the bodies of the vertebrae, from the crus on one side to that 
on the other, and transmits the aorta, vena azygos major, and thoracic duct. 
Sometimes the vena azygos major is transmitted upward through the right crus. 430 
THE MUSCLES AND FASCIA 
Occasionally some tendinous fibres are prolonged across the bodies of the ver- 
tebrae from the inner part of the lower end of the crura, passing behind the aorta, 
and thus converting the opening into a fibrous ring. 
The (Esophageal Opening (hiatus cesophageus) is situated at the level of the tenth 
dorsal vertebrae; it is elliptical in form, oblique in direction, muscular in structure, 
and, formed by the decussating fibres of the two crura, is placed above, and, at 
the same time, anterior, and a little to the left of the preceding. It transmits the 
oesophagus and pneumogastric nerves and some small oesophageal arteries. The 
anterior margin of this aperture is occasionally tendinous, being formed by the 
margin of the central tendon. The posterior and lateral margins are thick and 
the gullet is in contact with them for about half an inch. The right margin of 
the oesophageal opening is particularly prominent and lies in the oesophageal 
groove on the posterior surface of the left lobe of the liver. 
The Opening for the Vena Cava or the Foramen Quadratum (joramen vents caves) 
is the highest opening, being about on the level of the disk between the eighth 
and ninth dorsal vertebrae; it is quadrilateral in form, tendinous in structure, and 
placed at the junction of the right and middle leaflets of the central tendon, 
its margins being adherent to the wall of the inferior vena cava. 
The right crus transmits the greater and lesser splanchnic nerves of the right 
side; the left crus transmits the greater and lesser splanchnic nerves of the left 
side, and the vena azygos minor. The gangliated cords of the sympathetic 
usually enter the abdominal cavity by passing behind the internal arcuate liga- 
ments. 
Serous Membranes.-The serous membranes in relation with the Diaphragm are 
four in number: three lining its upper or thoracic surface; one, its abdominal. The 
three serous membranes on its upper surface are the pleura on either side and the 
pericardium, which covers the middle portion of the tendinous centre. The 
serous membrane covering the under surface of the Diaphragm is a portion of 
the general peritoneal membrane of the abdominal cavity. 
The 1 )iaphragm is arched, being convex toward the chest and concave toward the 
abdomen. 'The right portion forms a complete arch from before backward, being 
accurately moulded over the convex surface of the liver, and having resting upon 
it the concave base of the right lung. The left portion is arched from before back- 
ward in a similar manner; but the arch is narrower in front, being encroached upon 
by the pericardium, and lower than the right, at its summit, by about three-quarters 
of an inch. It supports the base of the left lung, and covers the great end of the 
stomach, the spleen, and left kidney. At its circumference the Diaphragm is 
higher in the mesial line of the body than at either side; but in the middle of the 
thorax the central portion, which supports the heart, is on a lower level than the 
two lateral portions. 
Nerves.-The Diaphragm is supplied by the phrenic nerves, the lower inter- 
costal nerves and the phrenic plexus of the sympathetic. 
Actions.-The Intercostals are the chief agents in the movement of the ribs 
in ordinary respiration. When the first rib is elevated and fixed by the Scaleni, the 
External intercostals raise the other ribs, especially their forepart, and so increase 
the capacity of the chest from before backward; at the same time they evert their 
lower borders, and so enlarge the thoracic cavity transversely. The Internal 
intercostals, at the side of the thorax, depress the ribs and invert their lower 
borders, and so diminish the thoracic cavity; but at the forepart of the chest these 
muscles assist the External intercostals in raising the cartilages.1 The Levatores 
1 The view of the action of the Intercostal muscles given in the text is that which is taught by Hutchinson 
(Cycl. of Anat, and Phys., art. Thorax), and is usually adopted in our schools. It is, however, much dis- 
puted. Hamberger believed that the External intercostals act as elevators of the ribs, or muscles of inspira- 
tion, while the internal act in expiration. Haller taught that both sets of muscles act in common-viz., as muscles 
of inspiration-and this view is adopted by many of the best anatomists of the Continent, and appears sup- OF THE THORAX 
431 
costarum assist the External intercostals in raising the ribs. The Triangularis 
sterni draws down the costal cartilages; it is therefore an expiratory muscle. 
The Diaphragm is the principal muscle of inspiration. When in a condition 
of rest the muscle presents a domed surface, concave toward the abdomen; and 
consists of a circumferential muscular and a central tendinous part. When 
the muscular fibres contract, they become less arched, or nearly straight, and 
thus cause the central tendon to descend, and in consequence the level of the 
chest-wall is lowered, the vertical diameter of the chest being proportionally 
increased. In this descent the different parts of the tendon move unequally. 
The left leaflet descends to the greatest extent; the right to a less extent, on 
account of the liver; and the central leaflet the least, because of its connection to 
the pericardium. In descending the Diaphragm presses on the abdominal viscera, 
and so to a certain extent causes a projection of the abdominal wall; but in conse- 
quence of these viscera not yielding completely, the central tendon becomes a fixed 
point, and enables the circumferential muscular fibres to act jrom it, and so elevate 
the lower ribs and expand the lower part of the thoracic cavity; and Duchenne 
has shown that the Diaphragm has the power of elevating the ribs, to which it 
is attached, by its contraction, if the abdominal viscera are in situ, but that if these 
organs are removed, this power is lost. When at the end of inspiration the Dia- 
phragm relaxes, the thoracic walls return to their natural position in consequence 
of their elastic reaction and of the elasticity and weight of the displaced viscera.1 
In all expulsive acts the Diaphragm is called into action, to give additional 
power to each expulsive effort. Thus, before sneezing, coughing, laughing, and 
crying, before vomiting, previous to the expulsion of the urine and faeces, or of 
the foetus from the womb, a deep inspiration takes place. 
The height of the Diaphragm is constantly varying during respiration, the 
muscle being carried upward or downward from the average level; its height also 
varies according to the degree of distention of the stomach and intestines, and the 
size of the liver. After a forced expiration, the right arch is on a level, in front, 
with the fourth costal cartilage; at the side, with the fifth, sixth, and seventh 
ribs; and behind, with the eighth rib, the left arch being usually from one to two 
ribs' breadth below the level of the right one. In a forced inspiration, it descends 
from one to two inches; its slope would then be represented by a line drawn 
from the ensiform cartilage toward the tenth rib. Prof. Wm. S. Forbes2 is of the 
opinion that the Diaphragm is an appendage of the circulatory apparatus rather 
than the chief agent in respiration. He maintains that the opening in the 
vena cava is stationary and holds a constant relation to the ninth dorsal verte- 
bra. He emphasizes the fact that the base of the pericardium is attached to the 
central tendon of the Diaphragm, and on the anterior and left side. The muscular 
fibres of the Diaphragm ascend upon and are attached to the pericardium. Pro- 
longations of the fibrous pericardium pass upward as the pericardial ligaments. 
These ligaments form fibrous planes reaching from each side of the central 
tendon of the Diaphragm to the " bony apex of the thoracic line " and to the 
fascia stretched across the thoracic apex, and they may be called the " superior 
tendinous crura." It is thus evident that the deep cervical fascia is connected 
to the lateral and superior parts of the pericardium. At birth the muscular 
ported by many observations made on the human subject under various conditions of disease, and on living 
animals after the muscles have been exposed under chloroform. The reader may consult an interesting paper 
by Dr. Cleland in the Journal of Anat, and Phys., No. II., May, 1867, p. 209, On the Hutchinsonian Theory 
of the Action of the Intercostal Muscles, who refers also to Henle, Luschka, Budge, and Baumler, Observa- 
tions on the Action of the Intercostal Muscles, Erlangen, 1860. (In New Syd. Soc.'s Year-book for 1861, p. 69.) 
Dr. W. W. Keen has come to the conclusion, from experiments made upon a criminal executed by hanging, 
that the External intercostals are muscles of expiration, as they pulled the ribs down, while the Internal inter- 
costals pulled the ribs up and are muscles of inspiration (Trans. Coll. Phys., Philadelphia, Third Series, vol. i., 
1875, p. 97). . . . 
1 For a detailed description of the general relations of the Diaphragm, and its action, refer to Dr. Sibson s 
Medical Anatomy. 
2 American Journal of the Medical Sciences, July, 1880. 432 
THE MUSCLES AND EAS CHE 
fibres of the Diaphragm contract at the first inspiration. The ductus arteriosus 
is lodged in an elliptical opening of a tendinous scaffolding. The contractions 
of the Diaphragm cause the tendinous scaffolding to compress the ductus arteri- 
osus 11 and eventually close it." The chief agents in the compression are the 
muscular fibres which pass from the Diaphragm to the pericardium. When the 
lateral wings of the Diaphragm descend they tend to form a vacuum in the thorax 
and thus assist the venous circulation. 
"The descent of the Diaphragm is not necessary to respiration," but it "is 
necessary in order to protect the heart from the movement of surrounding 
viscera, and in order to promote the free circulation of the blood through the 
vessels forming the cardiac roots." 
Muscles of Inspiration and Expiration.-The muscles which assist the action 
of the Diaphragm in ordinary tranquil inspiration are the Intercostals and the 
Levatores costarum, as above stated, and the Scaleni. When the need for more 
forcible action exists, the shoulders and the base of the scapula are fixed, and then 
the powerful muscles of forced inspiration come into play; the chief of these are 
the Trapezius, the Pectoralis minor, the Serratus posticus superior and inferior, 
and the Rhomboidei. The lower fibres of the Serratus magnus may possibly assist 
slightly in dilating the chest by raising and everting the ribs. The Sterno-mastoid 
also, when the head is fixed, assists in forced inspiration by drawing up the sternum 
and by fixing the clavicle, and thus affording a fixed point for the action of the 
muscles of the chest. The Ilio-costalis and Quadratus lumborum assist in forced 
inspiration by fixing the last rib. 
The ordinary action of expiration is hardly effected by muscular force, but 
results from a return of the walls of the thorax to a condition of rest, owing to 
their own elasticity and to that of the lungs. Forced expiratory actions are per- 
formed mainly by the flat muscles (Obliqui and Transversalis) of the abdomen, 
assisted by the Rectus. Other muscles of forced expiration are the Internal 
intercostals and Triangularis sterni (as above mentioned).1 
III. MUSCLES OF THE ABDOMEN 
The muscles of the abdomen may be divided into two groups: 1. The super- 
ficial muscles of the abdomen. 2. The deep muscles of the abdomen. 
1. The Superficial Muscles of the Abdomen. 
The Muscles in this region are, the 
External Oblique. 
Internal Oblique. 
Transversalis 
Rectus. 
Pyramidalis. 
Dissection (Fig. 288).-To dissect the abdominal muscles, make a vertical incision from the 
ensiform cartilage to the symphysis pubis; a second incision from the umbilicus obliquely upward 
and outward to the outer surface of the chest, as high as the lower border of the fifth or sixth 
rib; anti a third, commencing midway between the umbilicus and pubes, transversely outward 
to the anterior superior iliac spine, and along the crest of the ilium as far as its posterior third. 
Then reflect the three flaps included between these incisions from within outward, in the lines 
of direction of the muscular fibres. If necessary, the abdominal muscles may be made tense 
by inflating the peritoneal cavity through the umbilicus. 
1 A. M. Patterson (article on Myology, in D. J. Cunningham's Text-book of Anatomy) states that the move- 
ment of expiration is performed by the elasticity of the lungs, the weight of the chest-wall, the elevation of 
the Diaphragm, the action of the Triangularis sterni and muscles of the abdominal wall, possibly aided by the 
interosseous fibres of the Internal intercostal muscles. The same author states that the movement of inspira- 
tion is performed ordinarily by the descent of the Diaphragm and the action of this muscle in elevating the 
ribs, the action of the External intercostals and Levatores costarum, probably the action of the whole of each 
Internal intercostal, of the Scaleni, and of the Serrati postici. The accessory muscles of respiration are employed 
when voluntary respiratory effort is necessary. Patterson names them as follows: The Quadratus lumborum, 
Pectorales, Serratus magnus, Sterno-mastoid, Latissimus dorsi, Infra-hyoid muscles, Extensors of the spine. OE THE ABDOMEN 
433 
Superficial Fascia.-The superficial fascia of the abdomen consists, over the 
greater part of the abdominal wall, of a single layer of fascia, which contains a 
variable amount of fat; but as this layer approaches the groin it is easily divisible 
into two layers, between which are found the superficial vessels and nerves and 
the superficial inguinal lymphatic glands. The superficial layer of the superficial 
fascia, or the fascia of Camper, is thick, areolar in texture, containing adipose tissue 
in its meshes, the quantity of which varies in different subjects. Below it passes 
over Poupart's ligament, and is continuous with the outer layer of the superficial 
fascia of the thigh. In the male this fascia is continued over the penis and outer sur- 
face of the cord to the scrotum, where it helps to 
form the dartos. As it passes to the scrotum it 
changes its character, becoming thin, destitute of 
adipose tissue, and of a pale hue, it has a reddish 
color, and in the scrotum it acquires some invol- 
untary muscular fibres. From the scrotum it may 
be traced backward to be continuous with the 
superficial fascia of the perinseum. In the female 
this fascia is continued into the labia majora. 
The deep layer of the superficial fascia or the fascia 
of Scarpa, is thinner and more membranous in 
character than the superficial layer. In the mid- 
dle line it is intimately adherent to the linea alba 
and to the symphysis pubis, and is prolonged on 
to the dorsum of the penis, forming the suspen- 
sory ligament of the penis; above, it joins the 
superficial layer and is continuous with the 
superficial fascia over the rest of the trunk; 
below, it blends with the fascia lata of the 
thigh a little below Poupart's ligament; and 
below and internally it is continued over the 
penis and spermatic cord to the scrotum, where 
it helps to form the dartos. From the scrotum 
it may be traced backward to be continuous with the deep layer of the super- 
ficial fascia of the perimeum. In the female it is continued into the labia 
majora. 
Deep Fascia.-The deep fascia invests the external oblique muscle, but is so 
thin over the aponeurosis of the muscle as to be scarcely recognizable. 
The External or Descending Oblique Muscle (m. obliquus ext emus abdominis) 
(Fig. 289) is situated on the side and forepart of the abdomen; being the largest 
and the most superficial of the three flat muscles in this region. It is broad, thin, 
and irregularly quadrilateral, its muscular portion occupying the side, its aponeu- 
rosis the anterior wall, of the abdomen. It arises, by eight fleshy digitations, 
from the external surface and lower borders of the eight inferior ribs; these 
digitations are arranged in an oblique line running downward and backward; 
the upper ones being attached close to the cartilages of the corresponding ribs; 
the lowest, to the apex of the cartilage of the last rib; the intermediate ones, to 
the ribs at some distance from their cartilages. The five superior serrations 
increase in size from above downward, and are received between corresponding 
processes of the Serratus magnus; the three lower ones diminish in size from 
above downward, receiving between them corresponding processes from the Latis- 
simus dorsi. From these attachments, the fleshy fibres proceed in various direc- 
tions. Those from the lowest ribs pass nearly vertically downward, to be inserted 
into the anterior half of the outer lip of the crest of the ilium; the middle and 
upper fibres, directed downward and forward, terminate in an aponeurosis, oppo- 
3. Dis- 
section of 
inguinal 
hernia. 
Fig. 288.-Dissection of abdomen. 434 
THE MUSCLES AND FASCIAE 
site a line drawn from the prominence of the ninth costal cartilage to the anterior 
superior spinous process of the ilium. 
Aponeurosis of External Oblique.-The aponeurosis of the external oblique is a 
thin, but strong membranous aponeurosis, the fibres of which are directed 
obliquely downward and inward. It is joined with that of the opposite muscle 
along the median line, covers the whole of the front of the abdomen; above, it is 
connected with the lower border of the Pectoralis major; below, its fibres are closely 
PETIT'S 
TRIANGLE 
External abdo- 
minal ring. 
GimbernaV s 
ligament. 
Pubes. 
Fig. 289.-The External oblique muscle. 
aggregated together, and extend obliquely across from the anterior superior spine 
of the ilium to the spine of the os pubis and the linea ilio-pectinea. In the median 
line it interlaces with the aponeurosis of the opposite muscle, forming the linea 
alba, which extends from the ensiform cartilage to the symphysis pubis. 
That portion of the aponeurosis which extends between the anterior superior 
spine of the ilium and the spine of the os pubis is a broad band, folded inward, 
and continuous below with the fascia lata; it is called Poupart's ligament or the OF THE ABDOMEN 
435 
ligament of Fallopius. The portion which is reflected from Poupart's ligament 
at the spine of the os pubis along the pectineal line is called Gimbernat's ligament. 
From the point of attachment of the latter to the pectineal line, a few fibres 
pass upward and inward, behind the inner pillar of the ring, to the linea alba. 
They diverge as they ascend, and form a thin, triangular, fibrous layer, which is 
called the triangular fascia of the abdomen or Calles's ligament (Jigamentum 
inguinale reflexum). The point of the triangle is at the origin of Colles's ligament; 
the base is at the linea alba. Colles's ligament is in front of the conjoined tendon, 
the Rectus muscle, and the Pyramidalis muscle. 
In the aponeurosis of the External oblique, immediately above the crest of the 
os pubis, is a triangular opening, the external abdominal ring, formed by a separa- 
tion of the fibres of the aponeurosis in this situation. 
POUPART'S 
LIGAMENT 
INTERCOLUMNAR 
FIBRES 
FEMORAL 
RING" 
EXTERNAL 
ABDOMINAL 
RING 
<JIM BERN AT'S. 
LIGAMENT 
SAPHENOUS. 
OPENING 
FEMORAL 
VEIN 
LONG- 
SAPHENOUS 
VEIN 
Relations.-By its external surface, with the superficial fascia, superficial epi- 
gastric and circumflex iliac vessels, and some cutaneous nerves; by its internal 
surface, with the Internal oblique, the lower part of the eight inferior ribs, and 
Intercostal muscles, the Cremaster, the spermatic cord in the male, and round liga- 
ment in the female. Its posterior border, extending from the last rib to the crest 
of the ilium, is fleshy throughout and free; it is occasionally overlapped by the 
Latissimus dorsi, though generally a triangular interval exists between the two 
muscles near the crest of the ilium, in which is seen a portion of the internal 
oblique. This triangle, Petit's triangle (trigonum lumbxle), is therefore bounded 
in front by the External oblique, behind by the Latissimus dorsi, below by the 
crest of the ilium, while its floor is formed by the Internal oblique (Fig. 289). 
The following parts of the aponeurosis of the External oblique muscle require 
to be further described-viz., the external abdominal ring, the intercoiumnar fibres 
and fascia, Poupart's ligament, Gimbernat's ligament, and the triangular fascia of 
the abdomen. 
Fig. 290.-Right external abdominal ring and saphenous opening in the male. (Spalteholz.) THE MUSCLES AND FASCIAE 
436 
The External Abdominal Ring (annulus inguinalis subcutaneous') (Fig. 290).- 
Just above and to the outer side of the crest of the os pubis an interval is seen in the 
aponeurosis of the External oblique, called the external abdominal ring. The aper- 
ture is oblique in direction, somewhat triangular in form, and corresponds with 
the course of the fibres of the aponeurosis. It usually measures from base to apex 
about an inch, and transversely about half an inch. It is bounded below by the 
crest of the os pubis; above, by a series of curved fibres, the external spermatic, or 
the intercolumnar fibres (fibres intercrurales), which pass across the upper angle of 
the ring, so as to increase its strength; and on each side, by the margins of the 
opening in the aponeurosis, which are called the columns or pillars of the ring. 
The External Pillar or inferior crus (crus inferius) is inferior from the obliquity 
of its direction. It is stronger than the internal pillar; it is formed by that 
portion of Poupart's ligament which is inserted into the spine of the os pubis; it is 
curved so as to form a kind of groove, upon which the spermatic cord rests. 
The Internal Pillar or superior crus (crus superius) is a broad, thin, flat band, 
which is attached to the front of the symphysis pubis, interlacing with its fellow 
of the opposite side. 
The external abdominal ring gives passage to the spermatic cord in the male 
(funiculus spermaticus) and round ligament in the female (lig amentum teres uteri): 
it is much larger in men than in women, on account of the large size of the sper- 
matic cord, and hence the greater frequency of inguinal hernia in men. 
Intercolumnar Fibres (fibres intercrurales) (Fig. 290).-The intercolumnar fibres 
are a series of curved tendinous fibres, which arch across the lower part of 
the aponeurosis of the External oblique. They have received their name from 
stretching across between the two pillars of the external ring, describing a curve 
with the convexity downward. They are much thicker and stronger at the outer 
margin of the external ring, where they are connected to the outer third of Pou- 
part's ligament, than internally, where they are inserted into the linea alba. They 
are more strongly developed in the male than in the female. The inter- 
columnar fibres increase the strength of the lower part of the aponeurosis, 
and prevent the divergence of the pillars from one another. 
These intercolumnar fibres as they pass across the external abdominal ring 
are themselves connected together by delicate fibrous tissue, thus forming a fascia, 
which as it is attached to the pillars of the ring covers it in, and is called the 
intercolumnar fascia or the external spermatic fascia. This intercolumnar fascia 
is continued down as a tubular prolongation around the outer surface of the 
cord and testis or of the round ligament, and encloses them in a distinct sheath. 
The sac of an inguinal hernia, in passing through the external abdominal ring, receives an 
investment from the intercolumnar fascia. 
If the finger is introduced a short distance into the external abdominal ring 
and the limb is then extended and rotated outward, the aponeurosis of the External 
oblique, together with the iliac portion of the fascia lata, will be felt to become 
tense, and the external ring much contracted; if the limb is, on the contrary, Hexed 
upon the pelvis and rotated inward, this aponeurosis will become lax and the 
external abdominal ring sufficiently enlarged to admit the finger with compara- 
tive ease; hence the patient should always be put in the latter position when the 
taxis is applied for the reduction of an inguinal hernia in order that the abdominal 
walls may be relaxed as much as possible. 
Poupart's Ligament (ligamentum inguinale).-The portion of Poupart's ligament 
in front of the crural ring is called the superficial crural arch. Poupart's ligament 
is the lower border of the aponeurosis of the External oblique muscle, and extends 
from the anterior superior spine of the ilium to the pubic spine. From this 
latter point it is reflected outward to be attached to the pectineal line for about OF THE ABDOMEN 
437 
half an inch, forming Gimbernat's ligament. Its general direction is curved down- 
ward toward the thigh, where it is continuous with the fascia lata. Its outer half 
is rounded and oblique in direction. Its inner half gradually widens at its attach- 
ment to the os pubis, is more horizontal in direction, and lies beneath the spermatic 
cord. Nearly the whole of the space included between the crural arch and the 
innominate bone is filled in by the parts which descend from the abdomen into 
the thigh (Fig. 298). These will be referred to again on a subsequent page. 
Gimbernat's Ligament (ligamentum lacunare) (Figs. 290 and 298).-Gimbernat's 
ligament is that part of the aponeurosis of the External oblique muscle which is 
reflected upward and outward from the spine of the os pubis to be inserted into the 
pectineal line. It is about half an inch in length, larger in the male than in the 
female, almost horizontal in direction in the erect posture, and of a triangular form 
with the base directed outward. Its base, or outer margin, is concave, thin, and 
sharp, and lies in contact with the crural sheath, forming the inner boundary of 
the femoral or crural ring (annulus jemoralis). Its apex corresponds to the spine 
of the os pubis. Its posterior margin is attached to the pectineal line, and is con- 
tinuous with the pubic portion of the fascia lata. Its anterior margin is continuous 
with Poupart's ligament. Its surfaces are directed upward and downward. 
Triangular Fascia or Colles's Ligament (ligamentum inguinal refexum).-The 
triangular fascia of the abdomen is a layer of tendinous fibres of a triangular 
shape, which is attached by its apex to the pectineal line, where it is continuous 
with Gimbernat's ligament. It passes inward beneath the spermatic cord, and 
expands into a somewhat fan-shaped fascia, lying behind the inner pillar of the 
external abdominal ring, and in front of the conjoined tendon, and interlaces with 
the ligament of the other side at the linea alba. 
Ligament of Cooper (Fig. 298).-This is a strong ligamentous band, which was 
first described by Sir Astley Cooper. It extends upward and backward from the 
base of Gimbernat's ligament along the ilio-pectineal line, to which it is attached. 
It is strengthened by the fascia transversalis, by the pectineal aponeurosis, and 
by a lateral expansion from the lower attachment of the linea alba (adminiculum 
linear alboe). 
Suspensory Ligament of the Penis (ligamentum jundiforme penis).-The suspen- 
sory ligament of the penis arises from the linea alba, the anterior portion of 
the sheath of the Rectus muscle, and the superficial fascia. It splits into two 
portions, blends with the inserting fascia of the penis, and passes into the scrotum. 
Suspensory Ligament of the Clitoris (ligamentum jundijorme clitoridis).-The 
suspensory ligament of the clitoris corresponds in the female to the suspen- 
sory ligament of the penis in the male. 
Dissection-Detach the External oblique by dividing it across, just in front of its attach- 
ment to the ribs, as far as its posterior border, and separate it below from the crest of the ilium 
as far as the anterior superior spine; then separate the muscle carefully from the Internal oblique, 
which lies beneath, and turn it toward the opposite side. 
The Internal or Ascending Oblique Muscle (m. obliquus internus abdominis) 
(Fig. 291), thinner and smaller than the preceding, beneath which it lies, is of 
an irregularly quadrilateral form, and is situated at the side and forepart of the 
abdomen. It arises, by fleshy fibres, from the outer half of Poupart's ligament, 
being attached to the groove on its upper surface; from the anterior two-thirds 
of the middle lip of the crest of the ilium, and from the posterior lamella of the 
lumbar fascia (Fig. 295). From this origin the fibres diverge: those from Poupart's 
ligament, few in number and paler in color than the rest, arch downward and 
inward across the spermatic cord in the male and the round ligament in the 
female, and, becoming tendinous, are inserted, conjointly with those of the Trans- 
versalis, into the crest of the os pubis and pectineal line, to the extent of half an inch 
or more, forming what is known as the conjoined tendon of the Internal oblique and 438 
THE MUSCLES AND FASCIAE 
Transversalis; those from the anterior third of the iliac origin are horizontal in 
their direction, and, becoming tendinous along the lower fourth of the linea 
semilunaris, pass in front of the Rectus muscle to be inserted into the linea alba; 
those which arise from the middle third of the origin from the crest of the 
ilium pass obliquely upward and inward, and terminate in an aponeurosis which 
divides at the outer border of the Rectus muscle into two lamellie (Fig. 296), 
which are continued forward, in front and behind this muscle, to the linea alba, 
the posterior lamella being also connected to the cartilages of the seventh, eighth, 
and ninth ribs; the most posterior fibres pass almost vertically upward, to be 
inserted into the lower borders of the cartilages of the three lower ribs, being con- 
tinuous with the Internal intercostal muscles. 
Conjoined tendon. 
CREMASTER. 
Pubes. 
Fig. 291.-The Internal oblique muscle. 
The conjoined tendon of the Internal oblique and Transversalis is inserted into 
the crest of the os pubis and pectineal line, immediately behind the external 
abdominal ring, serving to protect what would otherwise be a weak point in the 
abdominal wall. Sometimes this tendon is insufficient to resist the pressure from 
within, and is carried forward in front of a protrusion through the external ring, 
forming one of the coverings of direct inguinal hernia; or the hernia forces its way 
through the fibres of the conjoined tendon. The conjoined tendon is sometimes 
divided into an outer and an inner portion-the former being termed the liga- 
ment of Hesselbach (Jigamentum inter foveolar e)', the latter, the ligament of Henle 
(Fig. 292). OE THE ABDOMEN 
439 
Aponeurosis of Internal Oblique.-The aponeurosis of the Internal oblique is 
continued forward to the middle line of the abdomen, where it joins with the 
aponeurosis of the opposite muscle at the linea alba, and extends from the margin 
of the thorax to the os pubis. At the outer margin of the Rectus muscle this 
aponeurosis, for the upper three-fourths of its extent, divides into two lamellae, 
which pass, one in front and the other behind the muscle, enclosing it in a kind of 
sheath, and reuniting on its inner border of the linea alba; the anterior layer is 
blended with the aponeurosis of the External oblique muscle; the posterior layer 
with that of the Transversalis. Along the lower fourth the aponeurosis passes 
altogether in front of the Rectus without any separation. Where the aponeurosis 
SEMILUNAR FOLD 
OF DOUGLAS 
TR A N S V E RS A LI S 
RECTUS 
ABDOMINIS' 
INTERNAL 
OBLIQUE 
DEEP EPI- 
GASTRIC ARTERY 
AND VEIN 
LIGAMENT OF HENLE 
LIGAMENT OF HESSELBACH 
Fig. 292.-The deep epigastric artery and veins, ligament of Henle and ligament of Hesselbach, seen 
from in front. (Modified from Braune.) 
ceases to split, and passes altogether in front of the Rectus muscle, a deficiency is 
left in the sheath of the muscle behind; this is marked above by a sharp lunated 
margin having its concavity downward. This is known as the semilunar fold of 
Douglas (linea semicircular is} (Fig. 293). 
Relations.-By its external surface, with the External oblique, Latissimus dorsi, 
spermatic cord, and external ring; by its internal surface, with the Transversalis 
muscle, the lower intercostal vessels and nerves, the ilio-hypogastric and the ilio- 
inguinal nerves. Near Poupart's ligament it lies on the fascia transversalis, 
internal ring, and spermatic cord. Its lower border forms the upper boundary 
of the inguinal canal. 
The Cremaster muscle (Fig. 291) is a thin, muscular layer, composed of a num- 
ber of fasciculi which arise from the inner part of Poupart's ligament, where its 
fibres are continuous with those of the Internal oblique and also occasionally with 
the Transversalis. It passes along the outer side of the spermatic cord, descends 
with it through the external abdominal ring upon the front and sides of the cord, 
and forms a series of loops which differ in thickness and length in different sub- 
jects. Those at the upper part of the cord are exceedingly short, but they become 
in succession longer and longer, the longest reaching down as low as the testicle, 
where a few are inserted into the tunica vaginalis. These loops are united together 
by areolar tissue, and form a thin covering over the cord and testis, the middle 440 
THE MUSCLES AND FASCIAE 
spermatic fascia (fascia cremaster ica). The fibres ascend along the inner side of 
the cord, and are inserted by a small pointed tendon into the crest' of the os 
pubis and front of the sheath of the Rectus muscle. 
LINE A ALBA 
POSTERIOR LEAF 
OF SHEATH OF 
RECTUS ABDOMINIS 
LINEA SEMILUNARIS 
-TRANSVERSALIS 
SEMILUNAR FOLD 
OF DOUGLAS 
RECTUS ABDOMINIS 
(cut through) 
ANTERIOR LEAF 
■OF SHEATH OF 
RECTUS ABDOMINIS 
Fig. 293.-The muscles of the abdomen, showing the semilunar fold of Douglas. Viewed from in front. 
(Spalteholz.) 
It will be observed that the origin and insertion of the Cremaster is precisely 
similar to that of the lower fibres of the Internal oblique. This fact affords an easy 
explanation of the manner in which the testicle and cord are invested by this 
muscle. At an early period of foetal life the testis is placed at the lower and back 
part of the abdominal cavity, but during its descent toward the scrotum, which 
takes place before birth, it passes beneath the arched fibres of the Internal oblique. 
In its passage beneath this muscle some fibres are derived from its lower part 
which accompany the testicle and cord into the scrotum. It occasionally happens OF THE ABDOMEN 
441 
that the loops of the Cremaster surround the cord, some lying behind as well as in 
front. It is probable that under these circumstances the testis, in its descent, 
passed through instead of beneath the fibres of the Internal oblique. 
In the descent of an oblique inguinal hernia, which takes the same course as 
the spermatic cord, the Cremaster muscle forms one of its coverings. This muscle 
becomes largely developed in cases of hydrocele and large old scrotal hernia. The 
Cremaster muscle is found only in the male, but almost constantly in the female 
Fig. 294.-The Transversalis, Rectus, and Pyramidalis muscles. 
a few muscular fibres may be seen on the surface of the round ligament, which 
correspond to this muscle, and in cases of oblique inguinal hernia in the female a 
considerable amount of muscular fibre may be found covering the sac. 
Dissection.-Detach the Internal oblique in order to expose the Transversalis beneath. This 
may be effected by dividing the muscle, above, at its attachment to the ribs; below, at its con- 
nection with Poupart's ligament and the crest of the ilium; and behind, by a vertical incision 442 
THE MUSCLES AND FASCIAE 
extending from the last rib to the crest of the ilium. The muscle should previously be made 
tense by drawing upon it with the fingers of the left hand, and if its division is carefully effected, 
the cellular interval between it and the Transversalis, as well as the direction of the fibres of the 
latter muscle, will afford a clear guide to their separation; along the crest of the ilium the cir- 
cumflex iliac vessels are interposed between them, and form an important guide in separating 
them. The muscle should then be thrown inward toward the linea alba. 
The Transversalis Muscle (m. transversus abdominis} (Fig. 294), so called 
from the direction of its fibres, is the most internal flat muscle of the abdomen, 
being placed immediately beneath the Internal oblique. It arises by fleshy fibres 
from the outer third of Poupart's ligament; from the inner lip of the crest of the 
ilium for its anterior three-fourths; from the inner surface of the cartilages of the 
six lower ribs, interdigitating with the Diaphragm; and from the lumbar fascia 
(Fig. 295), which may be regarded as the posterior aponeurosis of the muscle. 
The muscle terminates in front in a broad aponeurosis, the lower fibres of 
which curve downward and inward, and are inserted, together with those of the 
Internal oblique, into the lower part of the linea alba, the crest of the os pubis 
and pectineal line forming what is known as the conjoined tendon of the Internal 
oblique and Transversalis. The lowermost fibres help to form the posterior wall 
of the inguinal canal. Throughout the rest of its extent the aponeurosis passes 
horizontally inward, and is inserted into the linea alba, its upper three-fourths 
passing behind the Rectus muscle, blending with the posterior lamella of the 
Internal oblique; its lower fourth passing in front of the Rectus. The external 
portion of the lower fibres of the conjoined tendon is known as the ligament of 
Hesselbach; the internal portion as the ligament of Henle. 
Relations.-By its external surface, with the Internal oblique, the lower inter- 
costal nerves, and the inner surface of the cartilages of the lower ribs; by its 
internal surface, with the fascia transversalis, which separates it from the periton- 
eum. Its lower border forms the upper boundary of the inguinal canal. 
Dissection.-To expose the Rectus muscle, open its sheath by a vertical incision extending 
from the margin of the thorax to the os pubis, and then reflect the two portions from the surface 
of the muscle, which is easily done, excepting at the linese transversae, where so close an adhesion 
exists that the greatest care is requisite in separating them. Now raise the outer edge of the 
muscle, in order to examine the posterior layer of the sheath. By dividing the muscle in the 
centre, and turning its lower part downward, the point where the posterior wall of the sheath 
terminates in a thin curved margin will be seen. 
The Rectus Abdominis (Figs. 292, 294 and 296) is a long flat muscle, which 
extends along the whole length of the front of the abdomen, being separated from 
its fellow of the opposite side by the linea alba. It is much broader, but thinner, 
above than below, and arises by two tendons, the external or larger being attached 
to the crest of the os pubis, the internal, smaller portion interlacing with its fellow of 
the opposite side, and being connected with the ligaments covering the front of the 
symphysis pubis. The fibres ascend, and the muscle is inserted by three portions of 
unequal size into the cartilages of the fifth, sixth, and seventh ribs. The upper por- 
tion, attached principally to the cartilage of the fifth rib, usually has some fibres of 
insertion into the anterior extremity of the rib itself. Some fibres are occasionally 
connected with the costo-xiphoid ligaments and side of the ensiform cartilage. 
The Rectus muscle is traversed by tendinous intersections, three in number, 
which have received the name of linese transversae. One of these is usually 
situated opposite the umbilicus, and two above that point; of the latter, one 
corresponds to the extremity of the ensiform cartilage, and the other to the inter- 
val between the ensiform cartilage and the umbilicus. These intersections pass 
transversely or obliquely across the muscle in a zigzag course; they rarely extend 
completely through its substance, sometimes they pass only half-way across it, and 
are intimately adherent in front to the sheath in which the muscle is enclosed. OF THE ABDOMEN 
443 
Sometimes one or two additional lines may be seen, one usually below the 
umbilicus; the position of the other, when it exists, is variable. These addi- 
tional lines are for the most part incomplete. 
Fig. 295.-A transverse section of the abdomen in the lumbar region. 
The Rectus is enclosed in a sheath, the rectus sheath {vagina m. recti abdominis) 
(Figs. 295 and 296), formed by the aponeurosis of the Oblique and Transversalis 
SHEATH OF 
RECTUS ABDOMINIS 
(anterior leaf) 
Posterior leaf 
Anterior leaf 
Fig. 296.-Transition of the tendon of the right internal oblique into the sheath of the rectus. (Spalteholz.) 
SHEATH OF RECTUS ABDOMINIS 
muscles, which are arranged in the following manner. When the aponeurosis of the 
Internal oblique arrives at the outer margin of the Rectus it divides into two lamella1, THE MUSCLES AND FASCIAE 
444 
one of which passes in front of the Rectus, blending with the aponeurosis of the 
External oblique; the other, behind it, blending with the aponeurosis of the Trans- 
versalis; and these, joining again at its inner border, are inserted into the linea alba. 
This arrangement of the aponeuroses exists along the upper three-fourths of the 
muscle: at the commencement of the lower fourth, the posterior wall of the sheath 
terminates in a thin curved margin, the semilunar fold of Douglas (linea semicir- 
cular is) (Fig. 293), the concavity of which looks downward toward the pubes; the 
aponeuroses of all three muscles passing in front of the Rectus without any sepa- 
ration. A very thin aponeurotic layer does pass behind the lower one-fourth of 
the muscle, but it is trivial as compared with the thickness of the layer behind the 
upper three-fourths of the muscle. This sudden thinning causes the semilunar 
fold of Douglas. The extremities of the fold of Douglas descend as pillars to the 
os pubis. The inner pillar is attached to the symphysis pubis; the outer pillar 
passes downward as a distinct band on the inner side of the internal abdominal 
ring to join with the outer fibres of the conjoined tendon, and assist to form 
the ligament of Hesselbach. There its fibres divide into two sets, internal 
and external; the internal fibres are attached to the ascending ramus of the os 
pubis and the pectineal fascia; the external ones pass to the Psoas fascia, to 
the deep surface of Poupart's ligament, and to the tendon of the Transversalis on 
the outer side of the ring. The Rectus muscle, in the situation where its sheath 
is deficient, is separated from the peritoneum by the transversalis fascia. The 
convex outer border of the Rectus muscle corresponds to the linea semilunaris. 
The Pyramidalis is a small muscle, triangular in shape, placed at the lower 
part of the abdomen, in front of the Rectus, and contained in the same sheath 
with that muscle. It arises by tendinous fibres from the front of the os pubis 
and the anterior pubic ligament; the fleshy portion of the muscle passes upward, 
diminishing in size as it ascends, and terminates by a pointed extremity, which is 
inserted into the linea alba, midway between the umbilicus and the os pubis. This 
muscle is sometimes found wanting on one or both sides; the lower end of the 
Rectus then becomes proportionately increased in size. Occasionally it has been 
found double on one side, or the muscles of the two sides are of unequal size. 
Sometimes its length exceeds what is stated above. 
Besides the Rectus and Pyramidalis muscles, the sheath of the Rectus contains 
the superior and deep epigastric arteries, the terminations of the lumbar arteries 
and of the lower intercostal arteries and nerves. 
Nerves.-The abdominal muscles are supplied by the lower intercostal nerves. 
The Transversalis and Internal oblique also receive filaments from the hypogastric 
branch of the ilio-hypogastric and sometimes from the ilio-inguinal. The Cremas- 
ter is supplied by the genital branch of the Genito-crural. 
In the description of the abdominal muscles mention has frequently been made 
of the linea alba, lineae semilunares, and lineae transversae; when the dissection of 
the muscles is completed these structures should be examined. 
The Linea Alba (Figs. 293 and 296).-The linea alba is a tendinous raph^ seen 
along the middle line of the abdomen, extending from the ensiform cartilage to the 
symphysis pubis, to which it is attached. It is placed between the inner borders of 
the Recti muscles, and is formed by the blending of the aponeuroses of the Obliqui 
and Transversales muscles. It is narrow below, corresponding to the narrow inter- 
val existing between the Recti; but broader above, as these muscles diverge from one 
another in their ascent, becoming of considerable breadth when there is great dis- 
tention of the abdomen from pregnancy or ascites. It presents numerous apertures 
for the passage of vessels and nerves: the largest of these is the umbilicus (Fig. 297). 
The umbilicus is a fibrous ring formed by the fibres of the aponeurosis of the linea 
alba, is filled with scar tissue; in the foetus transmits the umbilical vein, the two 
hypogastric arteries, the allantoic duct, and the vitello-intestinal duct; but in the OF THE ABDOMEN 
445 
adult is obliterated, the cicatrix being stronger than the neighboring parts; hence 
umbilical hernia occurs in the adult near the umbilicus, whilst in the foetus it occurs 
at the umbilicus. The remains of the foetal structures are cord-like in character, 
and they diverge from the umbilicus within the 
abdomen. The remains of the umbilical vein con- 
stitute the round ligament of the liver, and this 
cord passes upward (Fig. 297). The remains of 
the hypogastric arteries pass downward (Fig. 297). 
The remains of the allantois become the urachus, 
which passes to the summit of the bladder (Fig. 
297). The depression of the umbilicus was 
created by the urachus. The linea alba is in re- 
lation, in front, with the integument, to which it 
is adherent, especially at the umbilicus; behind, 
it is separated from the peritoneum by the trans- 
versalis fascia; and below, by the urachus, and 
the bladder when that organ is distended. 
Ths Lineae Semilunares (Fig. 289).-The line® 
semilunares are two curved tendinous lines placed 
one on each side of the linea alba. Each corre- 
sponds with the outer border of the Rectus mus- 
cle, extends from the cartilage of the ninth rib 
to the pubic spine, and is formed by the aponeu- 
rosis of the Internal oblique at its point of division to enclose the Rectus, where 
it is reinforced in front by the External oblique and behind by the Transversalis. 
The Line® Transvers® (inscriptiones tendinew) (Fig. 289).-The line® trans- 
vers® are narrow transverse lines which intersect the Recti muscles, as already 
mentioned; they connect the line® semilunares with the linea alba. 
Actions.-The abdominal muscles perform a threefold action: 
When the pelvis and thorax are fixed, they compress the abdominal viscera, by 
constricting the cavity of the abdomen, in which action they are materially assisted 
by the descent of the Diaphragm. By these means the foetus is expelled from the 
uterus, the f®ces from the rectum, the urine from the bladder, and the contents of 
the stomach in vomiting. 
If the pelvis and spine are fixed, these muscles compress the lower part of the 
thorax, materially assisting expiration. If the pelvis alone is fixed, the thorax is 
bent directly forward when the muscles of both sides act, or to either side when 
those of the two sides act alternately, rotation of the trunk at the same time taking 
place to the opposite side. 
If the thorax is fixed, these muscles, acting together, draw the pelvis upward, 
as in climbing; or, acting singly, they draw the pelvis upward, and bend the 
vertebral column to one side or the other. The Recti muscles, acting from below, 
depress the thorax, and consequently flex the vertebral column; when acting from 
above, they flex the pelvis upon the vertebral column. The Pyramidalis are 
tensors of the linea alba. 
The Transversalis Fascia (fascia transversalis}.-The fascia transversalis is a 
thin aponeurotic membrane which lies between the inner surface of the Transversalis 
muscle and the extra-peritoneal fat. It forms part of the general layer of fascia 
which lines the interior of the abdominal and pelvis cavities, and is directly continu- 
ous with the iliac and pelvic fasci®. In the inguinal region the transversalis fascia is 
thick and dense in structure, and joined by fibres from the aponeurosis of the Trans- 
versalis muscle, but it becomes thin and cellular as it ascends to the Diaphragm, 
and blends with the fascia covering this muscle. In front, it unites across the 
middle line with the fascia on the opposite side of the body, and behind it becomes 
UMBILICAL 
VEIN 
LINEA ALBA 
-UMBILICUS 
-I NTE RVASCU LAR 
FOSSA 
HYPOGASTRIC 
ARTERY 
-URACHUS 
Fig. 297.-The umbilicus of the foetus 
seen from within the abdomen. (Poirier 
and Charpy.) 446 
THE MUSCLES AND FASCIA 
lost in the fat which covers the posterior surfaces of the kidneys. Below, it has 
the following attachments: posteriorly, it is connected to the whole length of the 
crest of the ilium, between the attachments of the Transversalis and Iliacus 
muscles; between the anterior superior spine of the ilium and the femoral vessels 
it is connected to the posterior margin of Poupart's ligament, and is there con- 
tinuous with the iliac fascia. Internal to the femoral vessels it is thin and attached 
to the os pubis and pectineal line, behind the conjoined tendon, with which it is 
united; and, corresponding to the point where the femoral vessels pass into the 
thigh, this fascia descends in front of them, forming the anterior wall of the crural 
sheath. Beneath Poupart's ligament it is strengthened by a band of fibrous tissue, 
which is only loosely connected to Poupart's ligament, and is specialized as the 
deep crural arch. The spermatic cord in the male and the round ligament in the 
female pass through this fascia; the point where they pass through is called the 
internal abdominal ring. This opening is not visible externally, owing to a pro- 
longation of the transversalis fascia on these structures, forming the infundibuliform 
fascia. 
The internal or deep abdominal ring (annulus inguinalis abdominis) (Figs. 292 
and 298) is situated in the transversalis fascia, midway between the anterior 
TRANSVERSALIS 
FASCIA 
INTERNAL 
ABDOMINAL 
RING 
CRURAL NERVE 
.ILIAC FASCIA 
■FEMORAL ARTERY 
7EMORAL VEIN 
CRURAL 
SEPTUM 
GIMBERNAT'S 
LIGAMENT 
COOPER'S 
LIGAMENT 
Fig. 298.-The relation of the femoral and internal abdominal rings, seen from within the abdomen after 
removal of the peritoneum. (Poirier and Charpy.) 
superior spine of the ilium and the symphysis pubis, and about half an inch above 
Poupart's ligament. It is of an oval form, the extremities of the oval directed 
upward and downward, varies in size in different subjects, and is much larger in 
the male than in the female. Its lower border is strengthened by the collection of 
fibres called Hesselbach's ligament, lying directly in front of the deep epigastric 
artery. It is the outer portion of the conjoined tendon fused with the outer 
pillar of the semilunar fold of Douglas. The internal ring is bounded, above 
and externally, by the arched fibres of the Transversalis; below and internally, 
by the deep epigastric vessels. It transmits the spermatic cord in the male 
and the round ligament in the female. From its circumference a thin funnel- 
shaped membrane, the infundibuliform or internal spermatic fascia, is continued 
round the cord and testis, enclosing them in a distinct pouch. OF THE ABDOMEN 
447 
EXTERNAL OBLIQUE 
(reflected inward) 
EXTERNAL OBLIQUE 
(reflected downward) 
POSTERIOR WALL OF 
INGUINAL CANAL 
INTERNAL ORIGIN 
OF CRENASTER 
Fig. 299.-The right inguinal canal in the male, second layer, viewed from in front. (The first layer 
is shown in Fig. 290.) (Spalteholz.) 
INTERNAL OBLIQUE 
(reflected inward) 
EXTERNAL OBLIQUE 
(reflected inward) 
INTERNAL 
OBLIQUE 
EXTERNAL 
OBLIQUE' 
(reflected 
downward) 
Fig. 300.-The right inguinal canal in the male, third layer, viewed from in front. (Spalteholz.) 448 
THE MUSCLES AND FASCIA 
When the sac of an oblique inguinal hernia passes through the internal or deep abdominal 
ring, the infundibuliform process of the transversalis fascia forms one of its coverings. 
The Inguinal or Spermatic Canal (canalis inguinalis} (Figs. 299 and 300).-The 
inguinal or spermatic canal contains the spermatic cord (funiculus spermaticus} in 
the male and the round ligament (ligamentum teres uteri} in the female. It is an 
oblique canal about an inch and a half in length, directed downward and inward, 
and placed parallel to and a little above Poupart's ligament. It commences above 
at the internal or deep abdominal ring, which is the point where the cord enters 
the spermatic canal, and terminates below at the external ring. It is bounded 
in front by the integument and superficial fascia, by the aponeurosis of the 
External oblique throughout its whole length, and by the Internal oblique for 
its outer third; behind, by the triangular fascia, the conjoined tendon of the 
Internal oblique and Transversalis, transversalis fascia, and the subperitoneal 
fat and peritoneum; above, by the arched fibres of the Internal oblique and Trans- 
versalis; below, by Gimbernat's ligament, and by the union of the fascia trans- 
versalis with Poupart's ligament. The median aspect of the floor of the canal is 
strengthened by dense fibres which are attached to the pubis and to the Rectus 
muscle. These fibres constitute the falx inguinalis. The deep epigastric artery 
passes upward and inward behind the canal lying close to the inner side of the 
internal abdominal ring (Fig. 292). The interval between this artery and the 
outer edge of the Rectus is named Hesselbach's triangle, the base of which is 
formed by Poupart's ligament. 
That form of protrusion in which the intestine follows the course of the spermatic cord along 
the spermatic canal is called oblique inguinal hernia. 
The Deep Crural Arch.-Curving over the vessels, just at the point where they 
become femoral, on the abdominal side of Poupart's ligament and loosely con- 
nected with it, is a thickened band of fibres called the deep crural arch. It is 
apparently a thickening of the fascia transversalis, joining externally to the centre 
of Poupart's ligament, and arching across the front of the crural sheath to be 
inserted by a broad attachment into the spine of the os pubis and ilio-pectineal 
line, behind the conjoined tendon. In some subjects this structure is not very 
prominently marked, and not infrequently it is altogether wanting. 
Cooper's Ligament or the Reflected Tendon of Cooper (Fig. 298) is a small reflection 
from the tendon of the Transversalis which passes downward and outward behind 
Gimbernat's ligament. 
Surface Form.-The only two muscles of this group which have any considerable influ- 
ence on surface form are the External oblique and Rectus muscles of the abdomen. With 
regard to the External oblique, the upper digitations of its origin from the ribs are well marked, 
intermingled with the serrations of the Serratus magnus; the lower digitations are not visible, 
being covered by the thick border of the Latissimus dorsi. Its attachment to the crest of the 
ilium, in conjunction with the Internal oblique, forms a thick oblique roll, which determines the 
iliac jurrow. Sometimes on the front of the lateral region of the abdomen an undulating out- 
line marks the spot where the muscular fibres terminate and the aponeurosis commences. The 
outer border of the Rectus is defined by the linea semilunaris, which may be exactly defined by 
putting the muscle into action. It corresponds with a curved line, with its convexity outward, 
drawn from the end of the cartilage of the ninth rib to the spine of the os pubis, so that the 
centre of the line, at or near the umbilicus, is three inches from the median line. The inner 
border of the Rectus corresponds to the linea alba, marked on the surface of the body by a 
groove, the abdominal furrow, which extends from the infrasternal fossa to, or to a little below, 
the umbilicus, where it gradually becomes lost. The surface of the Rectus presents three trans- 
verse furrows, the linese transversae. The upper two of these, one opposite or a little below the 
tip of the ensiform cartilage, and another, midway between this point and the umbilicus, are 
usually well marked; the third, opposite the umbilicus, is not so distinct. The umbilicus, situ- 
ated in the linea alba, varies very much in position as regards its level. It is always situated 
above a zone drawn round the body opposite the highest point of the crest of the ilium, gen- 
erally being about three-quarters of an inch to an inch above this line. It usually corresponds, 
therefore, to the fibro-cartilage between the third and fourth lumbar vertebrae. OF THE 1SCHIO- RECTAL REGION 
449 
2. The Deep Muscles of the Abdomen. 
Psoas magnus. 
Psoas parvus. 
Iliacus. 
Quadratus lumborum. 
The Psoas magnus, the Psoas parvus, and the Iliacus muscles, with the fascia 
covering them, will be described with the Muscles of the Lower Extremity. 
The Fascia Covering the Quadratus Lumborum (Fig. 295).-This is the most 
anterior of the three layers of the lumbar fascia. It is a thin layer of fascia, which, 
passing over the anterior surface of the Quadratus lumborum, is attached, inter- 
nally, to the bases of the transverse processes of the lumbar vertebrae; below, to 
the ilio-Iumbar ligament; and above, to the apex and lower border of the last rib. 
The portion of this fascia which extends from the transverse process of the 
first lumbar vertebra to the apex and lower border of the last rib constitutes the 
ligamentum arcuatum externum. 
The Quadratus Lumborum (Fig. 283) is situated in the lumbar region. It is 
irregularly quadrilateral in shape, and broader below than above. It arises by 
aponeurotic fibres from the ilio-lumbar ligament and the adjacent portion of the 
crest of the ilium for about two inches, and is inserted into the lower border of 
the last rib for about half its length, and by four small tendons, into the apices 
of the transverse processes of the four upper lumbar vertebrae. Occasionally a 
second portion of this muscle is found situated in front of the preceding. This 
arises from the upper borders of the transverse processes of three or four of the 
lower lumbar vertebrae, and is inserted into the lower margin of the last rib. The 
Quadratus lumborum is contained in a sheath formed by the anterior and middle 
lamellae of the lumbar fasciae. 
Relations.-Its anterior surface (or rather the fascia which covers its anterior 
surface) is in relation with the colon, the kidney, the Psoas muscle, and the 
Diaphragm. Between the fascia and the muscle are the last dorsal, ilio-hypogas- 
tric, and ilio-inguinal nerves. Its posterior surface is in relation with the middle 
lamella of the lumbar fascia, which separates it from the Erector spinae. The 
Quadratus lumborum extends, however, beyond the outer border of the Erector 
spinae. 
Nerve-supply.-The anterior branches of the last dorsal and first lumbar nerves; 
sometimes also a branch from the second lumbar nerve. 
Actions.-The Quadratus lumborum draws down the last rib. It acts as a 
muscle of inspiration by helping to fix the origin of the Diaphragm. If the thorax 
and spine are fixed, it may act upon the pelvis, raising it toward its own side 
when only one muscle is put in action; and when both muscles act together, either 
from below or above, they flex the trunk. 
IV. MUSCLES OF THE PELVIC OUTLET. 
The muscles of this region are situated at the pelvic outlet in the ischio-rectal 
region and the perinseum. They include the following: 
1. Muscles of the ischio-rectal region. 
2. Muscles of the perineum in the male. 
3. Muscles of the perinseum in the female. 
Corrugator cutis ani. 
External sphincter ani. 
1. The Muscles of the Ischio-rectal Region, 
Internal sphincter ani. 
Levator ani. 
The Corrugator Cutis Ani.-Around the anus is a thin stratum of involuntary 
muscular fibre, which radiates from the orifice. Internally, the fibres fade off 
Coccygeus. 450 
THE MUSCLES AND FASCIAE 
into the submucous tissue, while externally they blend with the true skin. By 
its contraction it raises the skin into ridges around the margin of the anus. 
The External Sphincter Ani (m. sphincter ani externus) (Figs. 301, 306,307, and 
308) is a thin, flat plane of muscular fibres, elliptical in shape and intimately adher- 
FRAENUM OF 
PREPUCE 
SHEATH OF 
RECTUS ABDOMINIS 
EXTERNAL 
ABDOMINAL RING 
FASCIA OF 
'penis 
INFERIOR 
RAMUS OF- 
ISCHIUM 
INFERIOR 
LAYER OF 
TRIANGULAR 
LIGAMENT 
TRANSVERSUS 
PERINEI 
SU PE R Fl CIA LI S 
TUBE ROSITY 
OF ISCHIUM 
OBTURATOR 
FASCIA 
ISC H IO - R E CTAL 
' FOSSA 
Fig. 301.-The muscles of the male perinseum, viewed from below. (Spalteholz.) 
ANO-COCCYGEAL LIGAMENT 
ent to the integument surrounding the margin of the anus. It measures about 
three or four inches in length from its anterior to its posterior extremity, being 
about an inch in breadth opposite the anus. It arises from the tip and back of 
the coccyx by a narrow tendinous band, and from the superficial fascia in front OF THE ISCHIO RECTAL REGION 
451 
of that bone; and is inserted into the raphe of the Accelerator urinae muscle and 
into the central tendinous point of the perimeum, joining with the two Superficial 
transverse perineal, the Levator ani, and the Accelerator urinae muscles. Many 
of the fibres are continuous with the Accelerator urinae in the male and with the 
Sphincter vaginae in the female. Often some of the fibres are continuous with the 
Transverse perineal muscles. It is continuous above with the Levator ani. Like 
other sphincter muscles, it consists of two planes of muscular fibre, which sur- 
round the margin of the anus and join in a commissure in front and behind, 
some fibres crossing from side to side in front and behind the anus. 
Nerve-supply.-A branch from the anterior division of the fourth sacral and 
the inferior haemorrhoidal branch of the internal pudic. 
Actions.-The action of this muscle is peculiar: 1. It is, like other sphincter 
muscles, always in a state of tonic contraction, and having no antagonistic muscle, 
it keeps the anal orifice closed. 2. It can be put into a condition of greater con- 
Ureter. 
PECTINEUS. 
Spermatic 
vessels. 
GRACILIS., 
ADDUCTOR 
LONGUS. 
Ampulla. 
Epididymis. 
Ampulla of vasa 
deferens. 
Testicle. 
OBTURATOR INTERNUS. 
Ascending ramus of. 
ISCHIUM. 
Coccyx. 
Internal pudic 
vessels and nerve. 
Fig. 302.--Side view of pelvis, showing Levator ani. (From a preparation in the Museum of the Royal 
College of Surgeons.) 
traction under the influence of the will, so as to occlude more firmly the anal 
aperture in expiratory efforts unconnected with defecation. 3. Taking its fixed 
point at the coccyx, it helps to fix the central point of the perinseum, so that the 
Accelerator urinae may act from this fixed point. 
'rhe Internal Sphincter Ani {m. sphincter ani internus) is a muscular ring 
which surrounds the lower extremity of the rectum for about an inch, its inferior 
border being contiguous to, but quite separate from, the External sphincter. 
'Phis muscle is about two lines in thickness, and is formed by an aggregation 
of the involuntary circular fibres of the intestine. It is paler in color and less 
coarse in texture than the External sphincter. 
Actions.-Its action is entirely involuntary. It helps the External sphincter 
to occlude the anal aperture. 
The Levator Ani (Figs. 302, 303, 304, and 305) is a broad, thin muscle, 
situated on each side of the pelvis. It is attached to the inner surface of the 452 
THE MUSCLES AND FASCIA 
sides of the true pelvis, and, descending, unites with its fellow of the opposite side 
to form the floor of the pelvic cavity. It supports the viscera in this cavity and 
surrounds the various structures which pass through it. It is usually possible to 
detect an interval between the fibres rising from the pubis and those rising from 
the pelvic fascia, and this interval marks the fact that the muscle described as one 
is really two. The pubic fibres constitute the Pubococcygeus muscle and the 
other fibres the Iliococcygeus muscle.1 
The Pubococcygeus muscle takes origin from the posterior aspect of the ramus 
of the pubis and from the most anterior portion of the tendinous arch of the 
Levator ani muscle. The fibres of origin from the pubis surround anteriorly the 
origin of the Internal obturator muscle. The muscle is a band, about one inch in 
width, thickest at its outer border, where it overlaps the Iliococcygeus. It passes 
backward, downward, and inward, "near the prostate in the male, the urethra 
and vagina in the female,"2 and near to the rectum. Most of the fibres pass back 
ANTERIOR SACRO- 
COCCYGEAL LIGAMENT 
GREAT SACRO- 
SCIATIC LIGAMENT 
TENDINOUS 
ARCH OF 
LEVATOR ANI 
OBTURATOR 
CANAL 
URETHRA 
SUPERIOR LAYER 
OF TRIANGULAR 
LIGAMENT 
Fig. 303.-The Levator ani of the male, viewed from above. (Spalteholz.) 
of the rectum, where they meet and join with the corresponding fibres of the 
opposite side. These united fibres form a thick, tendinous aponeurosis. "This 
is continued upward in front of the coccyx for some distance, and finally divides 
into two lateral portions, which have been named the ligamenta sacro-coccygea 
anterior. They are situated on either side of the middle sacral artery, and are 
finally inserted into the last one or two pieces of the sacrum and the first piece 
of the coccyx.''3 A few of the fibres of the Pubococcygeus muscle pass to the 
1 Peter Thompson. The Myology of the Pelvic Floor. 
2 Spalteholz's Atlas. Translated and edited by Barker. 
3 Peter Thompson. The Myology of the Pelvic Floor. OF THE ISCHIO-RECTAL REGION 
453 
central tendon of the perinaeum, come in contact with but do not terminate in the 
rectal wall, descend in front of and close to the anterior rectal wall, and terminate 
in the anterior portion of the sphincter ani and in the skin of the anus (Peter 
Thompson). 
Luschka and others believe that these anterior fibres descend among the longi- 
tudinal fibres of the rectum. It is certain that the most anterior fibres of the 
OBTURATOR 
CANAL 
URETHRA 
COWPER'S 
GLAN DS 
SUPERFICIAL TRANS- 
VERSUS PERINEI 
Fig. 304.-The right Levator ani in the male, viewed from the left. (Spalteholz.) 
Pubococcygeus muscle pass to the central point of the perinaeum. They pass 
"backward and downward on the side of the prostate, and in some cases on the 
side of the urethra immediately it emerges from the prostate."1 These anterior 
fibres in the female descend upon the side of the vagina. The anterior fibres 
are the preanal fibres of the Levator ani, They constitute what Santorini named 
1 Peter Thompson. The Myology of the Pelvic Floor. 454 
THE MUSCLES AND EASCEE 
the levator prostatse, because he regarded them as constituting a distinct 
muscle, which surrounds the prostate as a sling. Krause calls these fibres 
the levator urethrae; Testut, the fibres pre-rectales, and Prout, the Recto-urethralis 
muscle. 
The Iliococcygeus muscle arises from the tendinous arch of the Levator ani muscle 
(arcus tendineus m. levatoris ani). This arch is concave upward. The anterior 
end of the arch begins on the posterior surface of the superior ramus of the 
pubis. "The posterior end can be followed as far as the linea arcuata of the 
ilium, between these two points it descends for a variable distance, but always 
leaves the canalis obturatorius free."1 The fibres, coursing internally and down- 
ward, pass below the posterior portion of the Pubococcygeus. The anterior 
fibres join the fibres of the other side, between the anus and the tip of the coccyx 
in a median raphe. 
The posterior fibres are inserted into the sides of the last two pieces and into 
the tip of the coccyx. Peter Thompson points out that the Iliococcygeus muscle 
is liable to variations. It is strongly developed in but few, is usually thin, the 
muscular bundles being separated by membranous intervals; it may be replaced 
by fibrous tissue and may even be absent.2 
INTERNAL 
ILIAC ARTERY' 
OBTURATOR 
NERVE 
PARIETAL 
'PELVIC FASCIA 
.ATTACHMENT TO 
ISCHIAL SPINE 
ANTERIOR LAYER OF 
TRIANGULAR LIGAMENT' 
WHITE LINE 
POSTERIOR LAYER OF 
TRIANGULAR LIGAMENT 
WHITE LINE 
ORIGIN OF 
LEVATOR ANI 
VISCERAL 
PELVIC FASCIA 
OBTURATOR 
FASCIA 
Fig. 305.-The outer wall of the pelvis (pelvic fascia). (Cunningham.) 
Relations of the Levator Ani.-By its inner or pelvic surface, with the recto- 
vesical fascia, which separates it from the viscera of the pelvis and from the 
peritoneum. By its outer or perineal surface, it forms the inner boundary 
of the ischio-rectal fossa, and is covered by a thin layer of fascia, the ischio- 
rectal or anal fascia, given off from the obturator fascia. Its posterior border is 
free and separated from the Coccygeus muscle by a cellular interspace. Its 
anterior border is separated from the muscle of the opposite side by a triangular 
space, through which the urethra, and in the female the vagina, passes from the 
pelvis. 
Nerve-supply.-A branch from the anterior division of the fourth sacral nerve 
and a branch from the pudic nerve, which is sometimes derived from the perineal 
and sometimes from the inferior hemorrhoidal division. 
Actions.-The entire Levator ani muscle enters into the formation of the 
diaphragm of the pelvis and aids in supporting the rectum, vagina, and bladder. 
1 Spalteholz's Atlas. Translated and edited by Barker. 2 Myology of Muscles. OF THE PERINEUM IN THE MALE 
455 
The two parts of the muscle have different functions. The Iliococcygei have 
no other function than that of supporting the viscera. In early life they flex the 
vertebrae of the coccyx on one another and Hex the coccyx on the sacrum, but do 
not act directly at any age on the rectum or pelvic viscera (Peter Thompson). 
The Pubococcygei, especially in the female, have most important functions. 
They are the most influential supports of the pelvic floor and restore the pelvic 
floor to its proper position after the depression induced by parturition, defecation, 
and efforts at urination.1 Normally, they pull the perinaeum upward after the 
descending head has pulled it down. In some cases the contraction of the muscles 
actually obstructs the descent of the head (Peter Thompson). The muscles are 
strongly developed in females, and, acting with the Sphincter vaginae, they aid 
in contracting the vaginal canal. The muscles constrict the rectum and also lift 
the rectum with the pelvic floor. During defecation the position of the rectal 
contents is maintained by intra-abdominal pressure, the muscles lift the perinaeum 
over the fecal matter (Goffe). The Levator ani is also a muscle of forced 
expiration. 
The Coccygeus is a flat, triangular muscle situated behind and parallel with 
the preceding. It is a triangular plane of muscular and tendinous fibres, arising, 
by its apex, from the spine of the ischium, the obturator fascia, the edge of the 
great sacro-sciatic notch, and from the lesser sacro-sciatic ligament, and inserted, 
by its base, into the side of the lower two vertebrae of the sacrum and the upper 
two vertebrae of the coccyx. It assists the Levator ani and Pyriformis in closing 
in the back part of the outlet of the pelvis. 
Relations.-By its inner or pelvic surface, with the rectum. By its external 
surface, with the lesser sacro-sciatic ligament. The lower border is in relation 
with the posterior border of the Levator ani, but separated from it by a 
cellular interval: its upper border is in relation with the lower border of the 
Pyriformis, but separated from it by the sciatic and internal pudic vessels and 
nerve. 
Nerve-supply.-A branch from the fourth and fifth sacral nerves. 
Action.-The Coccygei muscles raise and support the coccyx, after it has been 
pressed backward during defecation or parturition. 
2. The Muscles and Fasciae of the Perinaeum in the Male (Figs. 301, 
306, 307, 308). 
Transversus perinei superficialis. 
Accelerator urinae. 
Erector penis. 
Compressor urethrae. 
Superficial Fascia (fascia superficialis perinei).-Th^ superficial fascia of the 
perinaeum consists of two layers, superficial and deep, as in other regions of the 
body. The superficial fascia over the posterior portion of the perinaeum is 
arranged in fatty layers which fill the ischio-rectal fossa on each' side of the 
rectum and anus. The superficial fascia over the anterior portion of the peri- 
naeum (urethral region) requires fuller consideration. 
The Superficial Layer is thick, loose, areolar in texture, and, except toward the 
scrotum, contains much adipose tissue in its meshes, the amount of which varies 
in different subjects. In front, it is continuous with the dartos of the scrotum; 
behind, it is continuous with the subcutaneous areolar tissue surrounding the 
anus; and, on either side, with the same fascia on the inner side of the thighs. In 
the middle line it is adherent to the skin of the raphe and to the deep layer of 
1 Peter Thompson. The Myology of the Pelvic Floor. THE MUSCLES AND FASCIAE 
456 
the superficial fascia. This layer should be carefully removed after it has been 
examined, when the deep layer will be exposed. 
The Deep Layer of Superficial Fascia or the Fascia of Colles is thin, aponeurotic 
in structure, and of considerable strength, serving to bind down the muscles of the 
root of the penis. It is continuous, in front, with the deep fascia of the penis, 
and the dartos of the scrotum, the fascia of the spermatic cord, and Scarpa's 
fascia upon the anterior portion of the abdomen; on either side it is firmly 
attached to the margins of the rami of the os pubis and ischium, external to 
the crus penis, and as far back as the tuberosity of the ischium; posteriorly, 
it curves down behind the Superficial transverse perineal muscles (reflected 
portion of fascia) to join the lower margin of the triangular ligament, which 
structure is a prolongation of the deep layer of the superficial fascia. The 
deep layer is attached to the superficial layer in the median line and to the 
Fig. 306.-The perinseum. The integument and superficial layer of superficial fascia reflected. 
median septum of the Accelerator urinse muscle. At the central tendon of the 
perinseum the reflected portion of the fascia becomes blended with the inser- 
tions of the External anal sphincter, the two Superficial transverse perineal 
muscles, and the Accelerator urime. This fascia not only covers the muscles 
in this region, but sends upward a vertical septum from its deep surface, which 
separates the back part of the subjacent space into two, the septum being 
incomplete in front. 
The Central Tendinous Point of the Perinaeum.-This is a fibrous point in the 
middle line of the perinaeum, between the urethra and the rectum, being about 
half an inch in front of the anus. At this point four muscles converge and are 
attached-viz., the External sphincter ani, the Accelerator urinae, and the two 
Superficial transverse perineal; so that by the contraction of these muscles, which 
extend in opposite directions, it serves as a fixed point of support. OF THE PERINEUM IN THE MALE 
The Transversus Perinei Superficialis is a narrow muscular slip, which passes 
more or less transversely across the back part of the perineal space. It arises 
by a small tendon from the inner and forepart of the tuberosity of the ischium, 
and, passing inward, is inserted into the central tendinous point of the perimeum, 
joining in this situation with the muscle of the opposite side, the External 
sphincter ani behind, and the Accelerator urinae in front. The base of the tri- 
angular ligament lies just beneath this muscle. 
Nerve-supply.-The perineal branch of the internal pudic. 
Actions.-By their contraction they serve to fix the central tendinous point of 
the perinaeum. 
The Accelerator Urinae, called also the Ejaculator seminis and the Ejaculator 
urinae (m. bulbocavernosus), is placed in the middle line of the perimeum, imme- 
diately in front of the anus. It consists of two symmetrical halves, united 
along the median line by a tendinous raphe. It arises from the central tendon 
457 
Transversus perinei 
superficialis.' 
■Superficial perineal artery 
■Superficial perineal nerve. 
GREAT SACRO- 
SCIATIC LIGAMENT 
.Internal pudic nerve. 
Internal pudic artery. 
Fig. 307.-The superficial muscles and vessels of the perinseum. 
of the perinseum, and from the median raph£ in front. From this point its fibres 
diverge like the plumes of a pen; the most posterior form a thin layer, which is 
lost on the anterior surface of the triangular ligament; the middle fibres encircle 
the bulb and adjacent parts of the corpus spongiosum, and join with the fibres 
of the opposite side, on the upper part of the corpus spongiosum, in a strong 
aponeurosis; the anterior fibres, the longest and most distinct, spread out over 
the sides of the corpus cavernosum, to be inserted partly into that body, anterior 
to the Erector penis, occasionally extending to the os pubis; partly terminating 
in a tendinous expansion, which covers the dorsal vessels of the penis. The latter 
fibres are best seen by dividing the muscle longitudinally, and dissecting it out- 
ward from the surface of the urethra. Many fibres of the External sphincter 
ani and of the Superficial transverse perineal muscles pass into this muscle. 
Action.-This muscle serves to empty the canal of the urethra, after the 
bladder has expelled its contents; during the greater part of the act of micturition 458 
THE MUSCLES AND FASCIAE 
its fibres are relaxed, and it only comes into action at the end of the process. 
The middle fibres are supposed, by Krause, to assist in the erection of the corpus 
spongiosum, by compressing the erectile tissue of the bulb. "The anterior fibres, 
on each side, which are known as Houston's • muscles, according to Tyrrel, also 
contribute to the erection of the penis, as they are inserted into, and continuous 
with, the fascia of the penis, compressing the dorsal vein during the contraction 
of the muscle. 
The Erector Penis (m. ischiocavernosus) covers part of the crus penis. It is an 
elongated muscle, broader in the middle than at either extremity, and situated on 
either side of the lateral boundary of the perinseum. It arises by tendinous and 
fleshy fibres from the inner surface of the tuberosity of the ischium, behind the 
crus penis, from the surface of the crus, and from the adjacent portion of the 
ramus of the ischium. From these points fleshy fibres succeed, which end 
in an aponeurosis which is inserted into the sides and under surface of the 
crus penis. 
Nerve-supply.-The perineal branch of the internal pudic. 
Anterior layer of 
deep perineal fascia removed, 
showing 
COMPRESSOR URETHRAE 
.Internal pudic artery. 
-Artery of the bulb. 
'Cowper's gland. 
Fig. 308.-Triangular ligament or deep perineal fascia. On the left side the anterior layer has been removed. 
Actions.-It compresses the crus penis and retards the return of the blood 
through the veins, and thus serves to maintain the organ erect. 
Between the muscles just examined a triangular space exists, bounded inter- 
nally by the Accelerator urinse, externally by the Erector penis, and behind by 
the Transversus perinei superficialis. The floor of this space is formed by the 
triangular ligament of the urethra (deep perineal fascia), and running from behind 
forward in it are the superficial perineal vessels and nerves, the long pudendal 
nerve, and the transverse perineal artery coursing along the posterior boundary 
of the space on the Transversus perinei suoerficial's. 
The Triangular Ligament or the Deep Perirel Fascia (trigomim or diaphragma 
urogenitale) (Figs. 305, 309, a d 310) is stretched almost horizontally across the 
pubic arch, so as to close in the front part of the outlet of the pelvis. It con- OF THE PERINEUM IN THE MALE 
459 
sists of two dense musculo-membranous laminae, which are united along their 
posterior borders, but are separated in front by intervening structures. The 
superficial of these two layers, the superficial, anterior, or inferior layer of the 
triangular ligament (fascia trigoni urogenitalis inferior}, is triangular in shape 
and about an inch and a half in depth. Its apex is directed forward, and is 
separated from the subpubic ligament by an oval opening for the transmission 
of the dorsal vein of the penis. The apex of the triangular ligament is called the 
PERITONEUM 
PROSTATIC 
FASCIA 
DEEP LAYER 
OF TRIANGULAR 
LIGAMENT 
COMPRESSOR 
URETH R/E 
MUSCLE 
DEEP LAYER OF 
SUPERFICIAL FASCIA 
SUPERFICIAL LAYER OF 
TRIANGULAR LIGAMENT 
Fig. 309.-The aponeurosis of the perinaeum. (Denonvilliers.) 
transverse perineal or transverse pelvic ligament (ligamentum transversum pelvis}. 
The lateral margins of the inferior layer of the triangular ligament are attached 
on each side to the rami of the ischium and os pubis, above the crura penis. 
The fusion of the two leaves posteriorly takes place beneath the Superficial 
transverse perineal muscles. The region of fusion of the two leaflets posteriorly 
is called the base. The base is directed toward the rectum, and connected to 
URETHRA- 
CORPUS 
SPONGIOSUM 
ERECTOR 
PEN IS 
DORSAL VEIN 
OF PENIS 
DORSAL NERVE 
OF PENIS 
DORSAL ARTERY 
OF PENIS 
CORPUS 
-CAVERNOSUM 
TRIANGULAR 
"LIGAMENT 
(upper margin) 
ARTERY TO 
BULB 
COM PRESSOR 
URETHRXE 
TRIANGULAR LIGAMENT 
(superficial layer) 
Fig. 310. The superficial layer of the triangular ligament. The Compressor urethrae muscle lies behind the 
superficial layer of the triangular ligament and is shown in the figure for convenience. (Poirier and Charpy.) 
the central tendinous point of the perinaeum. It is continuous with the deep 
layer of the superficial fascia behind the Superficial transverse perineal muscles, 
and with a thin fascia which covers the cutaneous surface of the Levator ani 
muscle, the anal or ischio-rectal fascia. 
This layer of the triangular ligament is perforated, about an inch below the 
symphysis pubis, by the urethra, the aperture for which is circular in form and 460 
THE MUSCLES AND FASCIAE 
about three or four lines in diameter; by the arteries to the bulb and the ducts of 
Cowper's glands close to the urethral orifice; by the arteries to the corpora caver- 
nosa-one on each side, close to the pubic arch and about half-way along the 
attached margin of the ligament; by the dorsal arteries and nerves of the penis near 
the apex of the ligament. Its base is also perforated by the superficial perineal 
vessels and nerves, while between its apex and the subpubic ligament the dorsal 
nerve of the penis and the dorsal vein of the penis passes upward into the 
pelvis. 
If this superficial or inferior layer of the triangular ligament is detached on 
either side, the following structures will be seen between it and the deeper 
layer: the dorsal vein of the penis; the membranous portion of the urethra, 
and the Compressor urethrae muscle; Cowper's glands and their ducts; the 
pudic vessels and dorsal nerve of the penis; the artery and nerve of the bulb, 
and a plexus of veins. The two layers join the urethral wall and vagina 
medianward. 
The deep, posterior, or superior layer (fascia trigoni urogenitalis superior) of the 
triangular ligament is derived from the obturator fascia and stretches across 
the pubic arch. If the obturator fascia is traced inward after covering the 
Obturator internus muscle, it will be found to be attached by some of its 
deeper or anterior fibres to the inner margin of the ischio-pubic ramus, while its 
superficial or posterior fibres pass over this attachment to become the superior 
layer of the triangular ligament. Behind, this layer of the fascia is continuous 
with the inferior layer and with the fascia of Colles, and in front it is separated 
from the apex of the prostate gland through the intervention of a prolongation of 
the recto-vesical fascia. It is pierced by the urethra, or rather consists of two 
halves which are separated in the middle line by the urethra passing between 
them. 
The Compressor or Constrictor Urethrae (m. constrictor urethra*) in the male 
surrounds the whole length of the membranous portion of the urethra, and is 
contained between the two layers of the triangular ligament. It arises, by apon- 
eurotic fibres, from the junction of the rami of the os pubis and ischium, to the 
extent of half or three-quarters of an inch: the point where the crura penis joins 
the transverse ligament of the perineum and the layers of the triangular liga- 
ment; each segment of the muscle passes inward, and divides into two fasciculi, 
which surround the membranous urethra and unite,, at the upper and lower 
surfaces of this tube, with the muscle of the opposite side by means of a tendinous 
raphC The Compressor urethrae is continuous posteriorly with the m. prostaticus 
and is continuous anteriorly with the circular fibres of the cavernous portion of 
the urethra. This muscle is frequently in two portions, an anterior and a 
posterior, separated by a distinct interval. In such cases the posterior fibres are 
called the transversus perinei profundus, and the anterior fibres are called the 
sphincter urethrae membranaceae. 
Nerve-supply.-The perineal branch of the internal pudic. 
Actions.-The muscles of both sides act together as a sphincter, compressing 
the membranous portion of the urethra. During the transmission of fluids they, 
like the Acceleratores urime, are relaxed, and come into action only at the end of 
the process, to eject the last drops of the fluid. 
3. The Muscles of the Perinaeum in the Female (Fig. 311). 
Transversus perinei superficialis. 
Sphincter vagina. 
Erector clitoridis. 
Compressor urethra 
The Transversus Perinei Superficialis in the female is a narrow muscular slip, 
which passes more or less transversely across the back part of the perineal space. OF THE PERINEUM IN THE FEMALE 
461 
It arises by a small tendon from the inner and forepart of the tuberosity of the 
ischium, and, passing inward, is inserted into the central point of the perinaeum, 
joining in this situation with the muscle of the opposite side, the External sphinc- 
ter ani behind, and the Sphincter vaginae in front. 
Nerve-supply.-The perineal branch of the internal pudic. 
Actions.-By their contraction they serve to fix the central tendinous point of 
the perinaeum. 
The Sphincter Vaginae (m. bzdbocavernosus) surrounds the orifice of the 
vagina, and is analogous to the Accelerator urinae in the male. It is attached 
posteriorly to the central tendinous point of the perinaeum, where it blends with 
TRANSVERSUS 
PERI NXEI. 
TUBER ISCHII. 
Fig. 311.-Muscles of the female perinaeum. 
the External sphincter ani. Its fibres pass forward on each side of the vagina, to 
be inserted into the corpora cavernosa of the clitoris, a fasciculus crossing over 
the body of the organ so as to compress the dorsal vein. 
Nerve-supply.-The perineal branch of the internal pudic. 
Actions.-It diminishes the orifice of the vagina. The anterior fibres contribute 
to the erection of the clitoris, as they are inserted into and are continuous with the 
fascia of the clitoris; compressing the dorsal vein during the contraction of the 
muscle. 
'The Erector Clitoridis (m. ischiocavernosus) resembles the Erector penis in the 
male, but is smaller than it. It covers the unattached part of the crus clitoridis. 
It is an elongated muscle, broader at the middle than at either extremity, and 
situated on either side of the lateral boundary of the perinaeum. It arises by 
tendinous and fleshy fibres from the inner surface of the tuberosity of the ischium, 
behind the crus clitoridis from the surface of the crus, and from the adjacent 
portion of the ramus of the ischium. From these points fleshy fibres succeed, THE MUSCLES AND FASCIAE 
462 
which end in an aponeurosis, which is inserted into the sides and under surface 
of the crus clitoridis. 
Nerve-supply.-The perineal branch of the internal pudic. 
Actions.-It compresses the crus clitoridis and retards the return of blood 
through the veins, and thus serves to maintain the organ erect. 
The Triangular Ligament (trigonum urogenitale) in the female is not so strong 
as in the male. It is divided in the middle line by the aperture of the vagina, 
with the external coat of which it becomes blended, and in front of this is 
perforated by the urethra. Its posterior border is continuous, as in the male, 
with the deep layer of the superficial fascia around the Transversus perinei 
muscle. 
Like the triangular ligament in the male, it consists of two layers, between 
which are to be found the following structures: the dorsal vein of the clitoris, 
a portion of the urethra and the Compressor urethrae muscle, the glands of Bar- 
tholin and their ducts; the pudic vessels and the dorsal nerve of the clitoris; the 
arteries of the bulbi vestibuli, and a plexus of veins. 
The Compressor Urethrae (m. constrictor urethrae) arises on each side from the 
margin of the descending ramus of the os pubis. The fibres, passing inward, 
divide into two sets: those of the forepart of the muscle are directed across the 
subpubic arch in front of the urethra to blend with the muscular fibres of the 
opposite side; while those of the hinder and larger part pass inward to blend with 
the wall of the vagina behind the urethra. 
Nerve-supply.-The perineal branch of the internal pudic. 
MUSCLES AND FASCI2E OF THE UPPER EXTREMITY. 
The muscles of the Upper Extremity are divisible into groups, corresponding 
with the different regions of the limb. 
I. Of the Thoracic Region. 
1. Anterior Thoracic Region. 
Pectoralis major. Pectoralis minor. 
Subclavius. 
2. Lateral Thoracic Region. 
Serratus magnus. 
II. Of the Shoulder and Arm. 
3. Acromial Region. 
Deltoid. 
4. Anterior Scapular Region. 
Subscapularis. 
5. Posterior Scapular Region. 
6. Anterior Humeral Region. 
Coraco-brachialis. Biceps. 
Brachialis anticus. 
7. Posterior Humeral Region. 
Triceps. Subanconeus. 
III. Of the Forearm. 
8. Anterior Radio-ulnar Region. 
Superficial 
Layer. 
Pronator radii teres. 
Flexor carpi radialis. 
Palmaris longus. 
Flexor carpi ulnaris. 
Flexor sublimis digitorum. 
Deep 
Layer. 
Flexor profundus digitorum. 
Flexor longus pollicis. 
Pronator quadratus. 
9. Radial Region. 
Supinator longus. 
Extensor carpi radialis longior. 
Extensor carpi radialis brevior. 
Supraspinatus. 
Infraspinatus. 
Teres minor. 
Teres major. THE ANTERIOR THORACIC REGION 
463 
10. Posterior Radio-Ulnar Region. 
Flexor brevis pollicis. 
Adductor obliquus pollicis. 
Adductor transversus pollicis. 
Extensor communis digitorum. 
Extensor minimi digiti. 
Extensor carpi ulnaris. 
Anconeus. 
Supinator brevis. 
Superficial 
Layer. 
12. Ulnar Region. 
Extensor ossis metacarpi pollici 
Extensor brevis pollicis. 
Extensor longus pollicis. 
Extensor indicis. 
Palmaris brevis. 
Abductor minimi digiti. 
Flexor brevis minimi digiti. 
Flexor ossis metacarpi minimi digiti 
(Opponens minimi digiti). 
Deep 
Layer. 
IV. Of the Hand. 
11. Radial Region. 
Abductor pollicis. 
Flexor ossis metacarpi pollicis 
(Opponens pollicis). 
13. Middle Palmar Region. 
Lumbricales. 
Interossei palmares. 
Interossei dorsales. 
Dissection of Pectoral Region and Axilla (Fig. 312).-The arm being drawn away from 
the side nearly at right angles with the trunk and rotated outward, make a vertical incision 
through the integument in the median line of the chest, from the upper to the lower part of the 
sternum; a second incision along the lower border of the Pectoral muscle, from the ensiform 
cartilage to the inner side of the axilla; a third, from the sternum along the clavicle, as far as its 
centre; and a fourth, from the middle of the clavicle obliquely downward, along the interspace 
between the Pectoral and Deltoid muscles, as low as the fold of the armpit. The flap of integu- 
ment is then to be dissected off in the direction indicated in the figure, but not entirely removed, 
as it should be replaced on completing the dissection. If a transverse incision is now made 
from the lower end of the sternum to the side of the chest, as far as the posterior fold of the 
armpit, and the integument reflected outward, the axillary space will be more completely exposed. 
I. THE MUSCLES AND FASCIA OF THE THORACIC REGION 
1. The Anterior Thoracic Region. 
Pectoralis major. 
Pectoralis minor. 
Superficial Fascia.-The superficial fascia of the thoracic region is a loose 
cellulo-fibrous layer enclosing masses of fat in its spaces. It is continuous with 
the superficial fascia of the neck and upper extremity above, and of the abdomen 
below. Opposite the mamma it divides into two layers, one of which passes in 
front, the other behind, that gland; and from both of these layers numerous septa 
pass into its substance, supporting its various lobes: from the anterior layer fibrous 
processes pass forward to the integument and nipple. These processes were called 
by Sir A. Cooper the suspensory ligaments (ligamenta suspensoria), from the sup- 
port they afford to the gland in this situation. 
Deep Fascia.-The deep thoracic fascia is a thin aponeurotic lamina, cover- 
ing the surface of the great Pectoral muscle, and sending numerous prolongations 
between its fasciculi: it is attached, in the middle line, to the front of the sternum, 
and above to the clavicle; externally and below it becomes continuous with the 
fascia over the shoulder, axilla, and thorax. It is very thin over the upper part 
of the muscle, thicker in the interval between the Pectoralis major and Latissimus 
dorsi, where it closes in the axillary space, and is known as the axillary fascia (jascia 
axillaris). It passes behind into the fascia of the Latissimus dorsi and Teres 
major, in front into the fascia of the deltoid and outward into the brachial 
fascia. The fascia of the Latissimus dorsi divides at the outer margin of the 
muscle into two layers, one of which passes in front and the other behind it; these 
proceed as far as the spinous processes of the dorsal vertebrae, to which they are 
Subclavius. THE MUSCLES AND FASCIA 
464 
attached. As the axillary fascia leaves the lower edge of the Pectoralis major to 
pass across the floor of the axilla it sends a layer upward under cover of the 
muscle, deep pectoral fascia: this lamina splits to envelop the Pectoralis minor, at 
the upper edge of which it becomes continuous with the costo-coracoid membrane, 
or the clavi-pectoral fascia. The hollow of the armpit, seen when the arm is 
abducted, is mainly produced by the traction of this fascia on the axillary floor, 
the axillary fascia (fascia axillaris), and hence it is sometimes named the 
suspensory ligament of the axilla. The axillary fascia (Fig. 313) is not a dis- 
tinct and complete rigid floor of the axillary space. Like all other fasciae, it 
follows muscular planes, and splits to encompass vessels, nerves, and muscles. 
In it are numerous perforations. In this fascia is a curved arch which often 
contains muscular fibres and which passes from the tendon of the great Pectoral, 
3. Dissection of 
Shoulder and Arm. 
1. Dissection of 
Pectoral Region 
and Axilla. 
2. Bend of Elbow. 
4 Forearm. 
5. Palm of Hand. 
Fig. 312.-Dissection of upper extremity. 
the Coraco-brachialis or the fascia over the biceps to the tendon of the Latissimus 
dorsi. This is called the axillary arch. Langer showed many years ago that there 
is an opening in the centre of the dense axillary fascia, the foramen of Langer. 
Through this opening axillary glands not unusually protrude. The axillary arch 
is the inner margin of the foramen of Langer. At the lower part of the thoracic 
region the deep thoracic fascia is well developed, and is continuous with the 
fibrous sheath of the Recti muscles. 
The Pectoralis Major (Fig. 314) is a broad, thick, triangular muscle, situated 
at the upper and forepart of the chest, in front of the axilla. It arises from the 
anterior surface of the sternal half of the clavicle; from half the breadth of the 
anterior surface of the sternum, as low down as the attachment of the cartilage 
of the sixth or seventh rib; this portion of its origin consists of aponeurotic fibres, 
which intersect with those of the opposite muscle; it also arises from the carti- THE ANTERIOR THORACIC REGION 
465 
lages of all true ribs, with the exception, frequently, of the first or of the seventh, 
or both; and from the aponeurosis of the External oblique muscle of the abdo- 
men. The fibres from this extensive origin converge toward its insertion, giving 
to the muscle a radiated appearance. 'Those fibres which arise from the clavicle 
pass obliquely outward and downward and are usually separated from the rest 
by a cellular interval: those from the lower part of the sternum, and the cartilages 
of the lower true ribs, pass upward and outward, whilst the middle fibres pass 
horizontally. They all terminate in a flat tendon, about two inches broad, which 
is inserted into the outer bicipital ridge of the humerus. This tendon consists of 
two laminae, placed one in front of the other, and usually blended together below. 
'The anterior, the thicker, receives the clavicular and upper half of the sternal 
portion of the muscle; and its fibres are inserted in the same order as that in 
which they arise; that is to say, the outermost fibres of origin from the clavicle are 
SUBSCAPULAR 
ARTERY AND VEIN 
PECTORALIS 
"MAJOR 
AXILLARY 
"ARCH 
AXILLARY 
"FASCIA 
TENDON OF 
LATISSIMUS DORSI 
Fig. 313.-The fascia of the right axilla, viewed from below. (Spalteholz.) 
inserted at the uppermost part of the tendon; the upper fibres of origin from the 
sternum pass down to the lowermost part of this anterior lamina of the tendon 
and extend as low as the tendon of the Deltoid and join with it. The posterior 
lamina of the tendon receives the attachment of the lower half of the sternal por- 
tion and the deeper part of the muscle from the costal cartilages. These deep 
fibres, and particularly those from the lower costal cartilages, ascend, the higher, 
turning backward successively behind the superficial and upper ones, so that the 
tendon appears to be twisted. The posterior lamina reaches higher on the humerus 
than does the anterior one, and from it an expansion is given off which covers 
the bicipital groove and blends with the capsule of the shoulder-joint. From the 
deepest fibres of this lamina at its insertion an expansion is given off which lines 
the bicipital groove of the humerus, while from the lower border of the tendon a 
third expansion passes downward to the fascia of the arm. Between the poste- 466 
THE MUSCLES AND EASCEE 
rior surface of the tendon of the great pectoral and the anterior surface of the 
long head of the biceps there is usually a bursa (bursa m. pectoralis major is). 
Relations.-By its anterior surface, with the integument, the superficial fascia, 
the Platysma, some of the branches of the descending cervical nerves, the mam- 
mary gland, and the deep fascia; by its posterior surface: its thoracic portion, with 
the sternum, the ribs and costal cartilages, the costo-coracoid membrane, the Sub- 
clavius, Pectoralis minor, Serratus magnus, and the Intercostals; its axillary por- 
Fig. 314.-Muscles of the chest and front of the arm. Superficial view. 
lion forms the anterior wall of the axillary space, and covers the axillary vessels and 
nerves, the Biceps and Coraco-brachialis muscles. Its upper border lies parallel 
with the Deltoid, from which it is separated by a slight interspace in which lie the 
cephalic vein and humeral branch of the acromial thoracic artery. Its lower border 
forms the anterior margin of the axilla, being at first separated from the Latissimus 
dorsi by a considerable interval; but both muscles gradually converge toward the 
outer part of the space. THE ANTERIOR THORACIC REGION 
467 
Dissection.-Detach the Pectoralis major by dividing the muscle along its attachment to 
the clavicle, and by making a vertical incision through its substance a little external to its line of 
attachment to the sternum and costal cartilages. The muscle should then be reflected outward, 
and its tendon carefully examined. The Pectoralis minor is now exposed, and immediately 
above it, in the interval between its upper border and the clavicle, a strong fascia, the costo- 
coracoid membrane. 
The Costo-coracoid Membrane or the Clavipectoral Fascia is a strong fascia, 
situated under cover of the clavicular portion of the Pectoralis major muscle. It 
occupies the interval between the Pectoralis minor and Subclavius muscle, and pro- 
tects the axillary vessels and nerves. Traced upward, it splits to enclose the Sub- 
clavius muscle, and its two layers are attached to the clavicle, one in front of and 
the other behind the muscle; the latter layer fuses with the deep cervical fascia and 
Fig. 315.-Muscles of the chest and front of the arm, showing some of the boundaries of the axilla. 
with the sheath of the axillary vessels. Internally, it blends with the fascia covering 
the first two intercostal spaces, and is attached also to the first rib internal to the 
origin of the Subclavius muscle. Externally it is very thick and dense, and is 
attached to the coracoid process. The portion extending from its attachment to 
the first rib to the coracoid process is often whiter and denser than the rest; this 
is sometimes called the costo-coracoid ligament. Below, it is thin, and at the upper 
border of the Pectoralis minor it splits into two layers to invest the muscle; from 
the lower border of the Pectoralis minor it is continued downward to join the axil- 
lary fascia, and outward to join the fascia over the short head of the Biceps. The 
costo-coracoid membrane is pierced by the cephalic vein, the acromial thoracic 
artery and vein, superior thoracic artery, and anterior thoracic nerves. 468 
THE MUSCLES AND FASCEE 
'The Pectoralis Minor (Fig. 315) is a thin, flat, triangular muscle, situated at 
the upper part of the thorax, beneath the Pectoralis major. It arises by three 
tendinous digitations from the upper margin and outer surface of the third, fourth, 
and fifth ribs, near their cartilages, and from the aponeurosis covering the Inter- 
costal muscles; the fibres pass upward and outward, and converge to form a flat 
tendon, which is inserted into the inner border and upper surface of the coracoid 
process of the scapula. 
Relations.-By its anterior surface, w'ith the Pectoralis major and the thoracic 
branches of the acromial thoracic artery. By its posterior surface, with the 
ribs, Intercostal muscles, Serratus magnus, the axillary space, and the axillary 
vessels and brachial plexus of nerves. Its upper border is separated from the 
clavicle by a triangular interval, broad internally, narrow externally, which is 
occupied by the costo-coracoid membrane. This space contains the first part of 
the axillary vessels and the axillary nerves. Running parallel to the lower border 
of the muscle is the long thoracic artery. 
The costo-coracoid membrane should now be removed, when the Subclavius muscle will 
be seen. 
The Subclavius is a small triangular muscle, placed in the interval between the 
clavicle and the first rib. It arises by a short, thick tendon from the first rib and 
its cartilage at their junction, in front of the rhomboid ligament; the fleshy fibres 
proceed obliquely upward and outward, to be inserted into a deep groove on the 
under surface of the clavicle. An extension from the aponeurosis of this muscle 
lies upon the subclavian vein. 
Relations.-By its upper surface, with the clavicle. By its deep surface it is 
separated from the first rib by the subclavian vessels and brachial plexus of nerves. 
Its anterior surface is separated from the Pectoralis major by the costo-coracoid 
membrane, which, with the clavicle, forms an osseo-fibrous sheath in which the 
muscle is enclosed. 
If the costal attachment of the Pectoralis minor is divided across, and the muscle reflected 
outward, the axillary vessels and nerves are brought fully into view, and should be examined. 
Nerves.-The Pectoral muscles are supplied by the anterior thoracic nerves; 
the Pectoralis major through these nerves receives filaments from all the spinal 
nerves entering into the formation of the brachial plexus; the Pectoralis minor 
receives its fibres from the eighth cervical and first dorsal nerves. The Subclavius 
is supplied by a filament from the fifth cervical nerve. 
Actions.-If the arm has been raised by the Deltoid, the Pectoralis major will, 
conjointly with the Latissimus dorsi and 'Teres major, depress it to the side of the 
chest. If acting alone, it adducts and draws forward the arm, bringing it across 
the front of the chest, and at the same time rotates it inward. The Pectoralis minor 
depresses the point of the shoulder, drawing the scapula downward and inward 
to the thorax, and throwing the inferior angle backward. The Subclavius de- 
presses the shoulder, drawing the clavicle downward and forward. When the 
arms are fixed, all three muscles act upon the ribs, drawing them upward and 
expanding the chest, and thus becoming very important agents in forced inspira- 
tion. Asthmatic patients always assume an attitude which fixes the shoulders, so 
that all these muscles may be brought into action to assist in dilating the cavity 
of the chest. 
2. The Lateral Thoracic Region. 
Serratus magnus. 
The Serratus Magnus (m. serratus anterior) (Figs. 315 and 316) is a thin, irregu- 
larly quadrilateral muscle, situated between the ribs and the scapula at the upper THE LATERAL THORACIC REGION 
469 
and lateral part of the chest. It arises by nine digitations or slips from the outer 
surface and upper border of the eight upper ribs (the second rib giving origin to 
two slips), and from the aponeurosis covering the corresponding intercostal muscles. 
From this extensive attachment the fibres pass backward, closely applied to the 
chest-wall, and reach the vertebral border of 
the scapula, and are inserted into its ventral 
aspect in the following manner. The upper 
two digitations-i. e., the one from the first 
rib and the higher of the two from the second 
rib-converge to be inserted into a triangular 
area on the ventral aspect of the superior 
angle. The next two digitations spread out 
to form a thin triangular sheet, the base of 
which is directed backward and is inserted 
into nearly the whole length of the ventral 
aspect of the vertebral border. The lower 
five digitations converge, as they pass back- 
ward from the ribs, to form a fan-shaped 
structure, the apex of which is inserted, 
partly by muscular and partly by tendinous 
fibres, into a triangular impression on the 
ventral aspect of the inferior angle. The 
lower four slips interdigitate at their origin 
with the upper five slips of the External 
oblique muscle of the abdomen. 
Relations.-This muscle is partly covered, 
in front, by the Pectoral muscles; behind, 
by the Subscapularis. The axillary vessels 
and nerves lie upon its upper part, while its 
deep surface rests upon the ribs and inter- 
costal muscles. 
Nerve.-The Serratus magnus is supplied 
by the posterior thoracic nerve, which is de- 
rived from the fifth, sixth, and generally the 
seventh cervical nerves. 
Actions.-The Serratus magnus, as a 
whole, carries the scapula forward, and at 
the same time raises the vertebral border of 
the bone. It is therefore concerned in the 
action of pushing. Its lower and stronger fibres move forward the lower angle 
and assist the Trapezius in rotating the bone round an axis through its centre, 
and thus assists this muscle in raising the acromion and supporting weights upon 
the shoulder. It is also an assistant to the Deltoid in raising the arm, inasmuch as 
during the action of this latter muscle it fixes the scapula and so steadies the glen- 
oid cavity on which the head of the humerus rotates. After the Deltoid has raised 
the arm to a right angle with the trunk, the Serratus magnus and the Trapezius, 
by rotating the scapula, raise the arm into an almost vertical position. It is pos- 
sible that when the shoulders are fixed the lower fibres of the Serratus magnus may 
assist in raising and everting the ribs; but it is not the important inspiratory muscle 
which it was formerly believed to be. 
Slip of SERRATUS 
magnus to first rib. 
Spine of 
scapula. 
i 
8 ■ 
SQ 
,EXTERNAL 
OBLIQUE. 
Eighth rib. 
Fig. 316.-Serratus magnus. (From a prepa- 
ration in the Museum of the Royal College of Sur- 
geons of England.) 
Surgical Anatomy.-When the muscle is paralyzed, the vertebral border, and especially 
the lower angle of the scapula, leaves the ribs and stands out prominently on the surface, giving 
a peculiar "winged" appearance to the back. The patient is unable to raise the arm, and an 470 
THE MUSCLES AND FASCIA 
attempt to do so is followed by a further projection of the lower angle of the scapula from the 
back of the thorax. 
Dissection.-After completing the dissection of the axilla, if the muscles of the back have 
been dissected, the upper extremity should be separated from the trunk. Saw through the 
clavicle at its centre, and then cut through the muscles which connect the scapula and arm with 
the trunk-viz., the Pectoralis minor in front, Serratus magnus at the side, and the Levator 
anguli scapulae, the Rhomboids, Trapezius, and Latissimus dorsi behind. These muscles should 
be cleaned and traced to their respective insertions. Then make an incision through the integu- 
ment, commencing at the outer third of the clavicle, and extending along the margin of that 
bone, the acromion process, and spine of the scapula; the integument should be dissected from 
above downward and outward, when the fascia covering the Deltoid is exposed (Fig. 312, No. 3). 
II. MUSCLES AND FASCIA OF THE SHOULDER AND ARM. 
Superficial Fascia.-The superficial fascia of the upper extremity is a thin 
cellulo-fibrous layer, containing the superficial veins and lymphatics, and the 
cutaneous nerves. It is most distinct in front of the elbow, and contains very large 
superficial veins and nerves; in the hand it is hardly demonstrable, the integument 
being closely adherent to the deep fascia by dense fibrous bands. Small sub- 
cutaneous bursae are found in this fascia over the acromion, the olecranon, and 
the knuckles. 
Deep Fascia.-The deep fascia of the upper extremity comprises the aponeurosis 
of the shoulder, arm, and forearm, the anterior and posterior annular ligaments of 
the carpus, and the palmar fascia. These will be considered in the description 
of the muscles of the several regions. 
3. The Acromial Region. 
Deltoid. 
Deep Fascia.-The deep fascia covering the Deltoid, and known as the deltoid 
aponeurosis, is a fibrous layer which covers the outer surface of the muscle, thick 
and strong behind, where it is continuous with the infraspinatus fascia, thinner 
over the rest of its extent. Tt sends down numerous prolongations between the 
fasciculi of the muscle. In front, it is continuous with the fascia covering the 
great Pectoral muscle; behind, with that covering the Infraspinatus; above, it 
is attached to the clavicle, the acromion, and spine of the scapula; below, it is 
continuous with the deep fascia of the arm. 
'The Deltoid (m. deltoideus) (Fig. 314) is a large, thick, triangular muscle, which 
gives the rounded outline to the shoulder, and has received its name from its resem- 
blance to the Greek letter a reversed. It surrounds the shoulder-joint in the greater 
part of its extent, covering it on its outer side, and in front and behind. It arises 
from the outer third of the anterior border and upper surface of the clavicle; from 
the outer margin and upper surface of the acromion process, and from the lower lip 
of the posterior border of the spine of the scapula, as far back as the triangular sur- 
face at its inner end. From this extensive origin the fibres converge toward their 
insertion, the middle passing vertically, the anterior obliquely backward, the pos- 
terior obliquely forward; they unite to form a thick tendon, which is inserted into 
a rough triangular prominence on the middle of the outer side of the shaft of the 
humerus. At its insertion the muscle gives off an expansion to the deep fascia of 
the arm. This muscle is remarkably coarse in texture, and the arrangement of 
its muscular fibres is somewhat peculiar; the central portion of the muscle-that 
is to say, the part arising from the acromion process-consists of oblique fibres, 
which arise in a bipenniform manner from the sides of tendinous intersections, 
generally four in number, which are attached above to the acromion process and 
pass downward parallel to one another in the substance of the muscle. The THE ANTERIOR SCAPULAR REGION 
471 
oblique muscular fibres thus formed are inserted into similar tendinous intersec- 
tions, generally three in number, which pass upward from the insertion of the 
muscle into the humerus and alternate with the descending septa. The portions 
of the muscle which arise from the clavicle and spine of the scapula are not 
arranged in this manner, but pass from their origin above, to be inserted into the 
margins of the inferior tendon. 
Relations.-By its superficial surjace, with the integument, the superficial and 
deep fasciae, Platysma, and supra-acromial nerves. Its deep surface is separated 
from the head of the humerus by a large sacculated synovial bursa, the subdeltoid, 
bursa (bursa subdeltoidea). It often communicates with the subacromial bursa 
(bursa subacromialis), which is between the acromial process and the coraco- 
acromial ligament above and the capsule of the shoulder-joint and the Supra- 
spinatus muscle below. The deep surface of the deltoid covers the coracoid 
process, coraco-acromial ligament, Pectoralis minor, Coraco-brachialis, both heads 
of the Biceps, the tendon of the Pectoralis major, the insertions of the Supra- 
spinatus, Infraspinatus, and 'Teres minor, the scapular and external heads of the 
Triceps, the circumflex vessels and nerve, and the humerus. Its anterior border 
is separated at its upper part from the Pectoralis major by a cellular interspace, 
which lodges the cephalic vein and humeral branch of the acromial thoracic artery: 
lower down the two muscles are in close contact. Its posterior border rests on the 
Infraspinatus and Triceps muscles. 
Nerves.-The Deltoid is supplied by the fifth and sixth cervical through the 
circumflex nerve. 
Actions.-The Deltoid raises the arm directly from the side, so as to bring it 
at right angles with the trunk, but this act cannot be performed without the aid 
of the Serratus magnus, which muscle steadies the lower angle of the scapula. 
Its anterior fibres, assisted by the Pectoralis major, draw the arm forward; and its 
posterior fibres, aided by the Teres major and Latissimus dorsi, draw it backward. 
Surgical Anatomy.-The Deltoid is very liable to atrophy, and when in this condition 
simulates dislocation of the shoulder-joint, as there is flattening of the shoulder and apparent 
prominence of the acromion process; upon examination, however, it will be found that the 
relative position of the great tuberosity of the humerus to the acromion and coracoid process is 
unchanged. Atrophy of the Deltoid may be due to disuse or loss of trophic influence, either 
from injury to the circumflex nerve or cord lesions, as in infantile paralysis. 
4. The Anterior Scapular Region. 
Subscapularis. 
Dissection.- Divide the Deltoid across, near its upper part, by an incision carried along the 
margin of the clavicle, the acromion process and spine of the scapula, and reflect it downward, 
when the structures under cover of it will be seen. 
The Subscapular Fascia (fascia subscapular is).-The subscapular fascia is a 
thin membrane attached to the entire circumference of the subscapular fossa, and 
affording attachment by its inner surface to some of the fibres of the Subscapu- 
laris muscle: when this is removed, the Subscapularis muscle is exposed. 
The Subscapularis (Fig. 315) is a large triangular muscle which fills up the 
subscapular fossa, arising from its internal two-thirds, with the exception of a 
narrow margin along the posterior border, and the surfaces at the superior and 
inferior angles which afford attachment to the Serratus magnus: it also arises from 
the lower two-thirds of the groove on the axillary border of the bone. Some fibres 
arise from tendinous laminae, which intersect the muscle, and are attached to ridges 
on the bone; and others from an aponeurosis, which separates the muscles from the 
Teres major and the long head of the Triceps. The fibres pass outward, and, 
gradually converging, terminate in a tendon, which is inserted into the lesser THE MUSCLES AND FASCIAE 
472 
tuberosity of the humerus. Those fibres which arise from the axillary border of 
the scapula are inserted into the neck of the humerus to the extent of an inch below 
the tuberosity. The tendon of the muscle is in close contact with the anterior part 
of the capsular ligament of the shoulder-joint, and glides over a large bursa, the 
bursa of the subscapularis muscle (bursa m. subscapularis, which separates it from 
the base of the coracoid process. This bursa communicates with the cavity of the 
joint by an aperture in the capsular ligament. 
Relations.-Its anterior surface forms a considerable part of the posterior wall 
of the axilla, and is in relation with the Serratus magnus, Coraco-brachialis, and 
Biceps, the axillary vessels and brachial plexus of nerves, and the subscapular 
vessels and nerves. By its posterior surface, with the scapula and the capsular 
ligament of the shoulder-joint. Its lower border is contiguous with the Teres major 
and Latissimus dorsi. 
Nerves.-It is supplied by the fifth and sixth cervical nerves through the upper 
and lower subscapular nerves. 
Actions.-The Subscapularis rotates the head of the humerus inward; when 
the arm is raised, it draws the humerus forward and downward. It is a powerful 
defence to the front of the shoulder-joint, preventing displacement of the head of 
the bone. 
5. The Posterior Scapular Region (Fig. 317). 
Supraspinatus. 
Infraspinatus. 
Teres minor. 
Teres major. 
Dissection.-To expose these muscles, and to examine their mode of insertion into the 
humerus, detach the deltoid and Trapezius from their attachment to the spine of the scapula 
and acromion process. Remove the clavicle by dividing the ligaments connecting it with the 
coracoid process, and separate it at its articulation with the scapula: divide the acromion process 
near its root with a saw. The fragments being removed, the tendons of the posterior Scapular 
muscles will be fully exposed, and can be examined. A block should be placed beneath the 
shoulder-joint, so as to make the muscles tense. 
The Supraspinatus Fascia (fascia supraspinata).-The supraspinatus fascia is 
a thick and dense membranous layer, which completes the osseo-fibrous case 
in which the Supraspinatus muscle is contained, affording attachment, by its 
inner surface, to some of the fibres of the muscle. It is thick internally, but 
thinner externally under the coraco-acromial ligament. When this fascia is 
removed, the Supraspinatus muscle is exposed. 
The Supraspinatus Muscle occupies the whole of the supraspinatus fossa, 
arising from its internal two-thirds and from the strong fascia which covers its sur- 
face. The muscular fibres converge to a tendon which passes across the upper 
part of the capsular ligament of the shoulder-joint, to which it is intimately adher- 
ent, and is inserted into the highest of the three facets on the great tuberosity of 
the humerus. 
Relations.-By its upper surface, with the Trapezius, the clavicle, the acromion, 
the coraco-acromial ligament, and the Deltoid; by its under surface, with the 
scapula, the suprascapular vessels and nerve, and upper part of the shoulder-joint. 
The Infraspinatus Fascia (fascia infraspinata).-The infraspinatus fascia is 
a dense fibrous membrane, covering in the Infraspinatus muscle and attached 
to the circumference of the infraspinatus fossa; it affords attachment, by its inner 
surface, to some fibres of that muscle. At the point where the Infraspinatus 
commences to be covered by the Deltoid, this fascia divides into two layers: one 
layer passes over the Deltoid muscle, helping to form the Deltoid fascia already 
described; the other passes beneath the Deltoid to the capsule of the shoulder-joint. 
The Infraspinatus is a thick, triangular muscle, which occupies the chief part 
of the infraspinatus fossa, arising by fleshy fibres from its internal two-thirds, and THE POSTERIOR SCAPULAR REGION 
473 
by tendinous fibres from the ridges on its surface: it also arises from a strong 
fascia which covers it externally, and separates it from the Teres major and minor. 
The fibres converge to a tendon which glides over the external border of the 
spine of the scapula, and, passing across the posterior part of the capsular ligament 
of the shoulder-joint, is inserted into the middle facet on the great tuberosity of 
the humerus. The tendon of this muscle has interposed between it and the joint 
capsule a synovial bursa, the bursa of the Infraspinatus muscle (bursa m. infra- 
spinati), which communicates with the synovial cavity of the shoulder-joint. 
Relations.-By its posterior surface, with the Deltoid, the Trapezius, Latissimus 
dorsi, and the integument; by its anterior surface, with the scapula, from which 
it is separated by the suprascapular and dorsalis scapulae vessels, and with the 
Fig. 317.-Muscles on the dorsum of the Scapula and the Triceps. 
capsular ligament of the shoulder-joint. Its lower border is in contact with the 
Teres minor, occasionally united with it, and with the Teres major. 
The Teres Minor is a narrow, elongated muscle, which arises from the dorsal 
surface of the axillary border of the scapula for the upper two-thirds of its extent, 
and from two aponeurotic laminae, one of which separates this muscle from the 
Infraspinatus, the other from the Teres major; its fibres pass obliquely upward 
and outward, and terminate in a tendon which is inserted into the lowest of the 
three facets on the great tuberosity of the humerus, and, by fleshy fibres, into the 
humerus immediately below it. The tendon of this muscle passes across the 
posterior part of the capsular ligament of the shoulder-joint. 
Relations.-By its posterior surface, with the Deltoid and the integument; 
by its anterior surface, with the scapula and dorsal branch of the subscapular 
artery, the long head of the Triceps, and the shoulder-joint; by its upper border, 474 
THE MUSCLES AND FASCIAE 
with the Infraspinatus; by its lower border, with the Teres major, from which it 
is separated anteriorly by the long head of the Triceps. 
The Teres Major is a thick but somewhat flattened muscle, which arises from 
the oval surface on the dorsal aspect of the inferior angle of the scapula, and from 
the fibrous septa interposed between it and the Teres minor and Infraspinatus; the 
fibres are directed upward and outward, and terminate in a flat tendon, about two 
inches in length, which is inserted into the inner bicipital ridge of the humerus. 
The tendon of this muscle, at its insertion into the humerus, lies behind that of the 
Latissimus dorsi, from which it is separated by a synovial bursa, the bursa of the 
Latissimus dorsi muscle (bursa m. latissimi dorsi), the two tendons being, however, 
united along their lower borders for a short distance. Between the tendon of 
the Teres major and the bone is the bursa m. teretis majoris. 
Relations.-By its posterior surface, with the Latissimus dorsi below, and the 
long head of the Triceps above. By its anterior surface, with the Subscapularis, 
Latissimus dorsi, Coraco-brachialis, short head of the Biceps, the axillary vessels, 
and brachial plexus of nerves. Its upper border is at first in relation with the 
Teres minor, from which it is afterward separated by the long head of the Triceps. 
Its lower border forms, in conjunction with the Latissimus dorsi, part of the pos- 
terior boundary of the axilla. The Latissimus dorsi at first covers the origin of 
the Teres major, then wraps itself obliquely round its lower border, so that its 
tendon ultimately comes to lie in front of that of the Teres major. 
Nerves.-The Supra- and Infraspinatus muscles are supplied by the fifth and 
sixth cervical nerves through the suprascapular nerve; the Teres minor, by the 
fifth cervical, through the circumflex; and the Teres major, by the fifth and sixth 
cervical, through the lower subscapular. 
Actions.-The Supraspinatus assists the Deltoid in raising the arm from the 
side, and fixes the head of the humerus in the glenoid cavity. The Infraspinatus 
and Teres minor rotate the head of the humerus outward: when the arm is raised, 
they assist in retaining it in that position and carrying it backward. One of the 
most important uses of these three muscles is the great protection they afford to 
the shoulder-joint, the Supraspinatus supporting it above, and preventing displace- 
ment of the head of the humerus upward, while the Infraspinatus and Teres minor 
protect it behind, and prevent dislocation backward. The Teres major assists the 
Latissimus dorsi in drawing the humerus downward and backward, when pre- 
viously raised, and rotating it inward; when the arm is fixed, it may assist the 
Pectoral and Latissimus dorsi muscles in drawing the trunk forward. 
THE MUSCLES AND FASCIA OF THE ARM. 
6. The Anterior Humeral Region (Fig. 315). 
Coraco-brachialis. 
Biceps. 
Brachialis anticus. 
Dissection.-The arm being placed on the table, with the front surface uppermost, make 
a vertical incision through the integument along the middle line, from the clavicle to about 
two inches below the elbow-joint, where it should be joined by a transverse incision, extending 
from the inner to the outer side of the forearm; the two flaps being reflected on either side, 
the fascia should be examined (Fig. 312). 
Deep Fascia (fascia bracbii).-The deep fascia of the arm is continuous with 
that covering the Deltoid and the great Pectoral muscles, by means of which it is 
attached, above, to the clavicle, acromion, and spine of the scapula, and is also 
continuous with the axillary fascia. It forms a thin, loose, membranous sheath 
investing the muscles of the arm, sending down septa between them, and com- 
posed of fibres disposed in a circular or spiral direction, and connected together 
by vertical and oblique fibres. It differs in thickness at different parts, being THE ANTERIOR HUMERAL REGION 
475 
thin over the Biceps, but thicker where it covers the Triceps, and over the 
condyles of the humerus; it is strengthened by fibrous aponeuroses, derived 
from the Pectoralis major and Latissimus dorsi on the inner side, and from the 
Deltoid externally. On either side it gives off a strong intermuscular septum, 
which is attached to the supracondylar ridge and condyle of the humerus. These 
septa serve to separate the muscles of the anterior from those of the posterior 
brachial region. The external intermuscular septum {septum intermuscidare 
laterale) extends from the lower part of the anterior bicipital ridge, along the 
external supracondylar ridge, to the outer condyle; it is blended with the tendon 
of the Deltoid, gives attachment to the Triceps behind, to the Brachialis anticus, 
Supinator longus, and Extensor carpi radialis longior, in front, and is perforated 
by the musculo-spiral nerve and superior profunda artery. The internal inter- 
muscular septum {septum intermuscular e mediate), thicker than the preceding, 
extends from the lower part of the posterior lip of the bicipital groove below the 
Teres major, along the internal supracondylar ridge to the inner condyle; it is 
blended with the tendon of the Coraco-brachialis, and affords attachment to the 
Triceps behind, and the Brachialis anticus in front. It is perforated by the ulnar 
nerve and the inferior profunda and anastomotic arteries. At the elbow the deep 
fascia is attached to all the prominent points round the joint-viz., the condyles of 
the humerus and the olecranon process of the ulna-and is continuous with the 
deep fascia of the forearm. Just below the middle of the arm, on its inner side, in 
front of the intermuscular septum, is an oval opening in the deep fascia which 
transmits the basilic vein and some lymphatic vessels. On the removal of this 
fascia the muscles, vessels, and nerves of the anterior humeral region are exposed. 
The Coraco-brachialis, the smallest of the three muscles in this region, is 
situated at the upper and inner part of the arm. It arises by fleshy fibres from 
the apex of the coracoid process, in common with the short head of the Biceps, 
and from the intermuscular septum between the two muscles; the fibres pass 
downward, backward, and a little outward, to be inserted by means of a flat 
tendon into an impression at the middle of the inner surface and internal border 
of the shaft of the humerus between the origins of the Triceps and Brachialis 
anticus. It is perforated by the musculo-cutaneous nerve. The inner border of 
the muscle forms a guide to the position of the brachial artery in tying the vessel 
in the upper part of its course. Between the tendon of the subscapularis, 
the coracoid process and the tendon of the Coraco-brachialis, is the bursa of the 
Coraco-brachialis muscle {bursa m. coracobrachialis). 
Relations.-By its anterior surface, with the Pectoralis major above, and at 
its insertion with the brachial vessels and median nerve which cross it; by its 
posterior surface, with the tendons of the Subscapularis, Latissimus dorsi, and 
Teres major, the inner head of the Triceps, the humerus, and the anterior circum- 
flex vessels; by its inner border, with the brachial artery, and the median and 
musculo-cutaneous nerves; by its outer border, with the short head of the Biceps 
and Brachialis anticus. 
The Biceps or the Biceps Flexor Cubiti {m. biceps brachii) is a long fusiform 
muscle, occupying the whole of the anterior surface of the arm, and divided above 
into two portions or heads, from which circumstance it has received its name. The 
short head {caput breve) arises by a thick flattened tendon from the apex of the cora- 
coid process, in common with the Coraco-brachialis. The long head {caput longum) 
arises from the upper margin of the glenoid cavity, and is continuous with the 
glenoid ligament. This tendon arches over the head of the humerus, being enclosed 
in a special sheath of the synovial membrane of the shoulder-joint; it then passes 
through an opening in the capsular ligament at its attachment to the humerus, 
and descends in the bicipital groove, in which it is retained by a fibrous prolonga- 
tion from the tendon of the Pectoralis major. Each tendon is succeeded by an 476 
THE MUSCLES AND FASCIAE 
elongated muscular belly, and the two bellies, although closely applied to each 
other, can readily be separated until within about three inches of the elbow-joint. 
Here they end in a flattened tendon, which is inserted into the back part of the 
tuberosity of the radius, a synovial bursa (bursa bicipito-radialis), being interposed 
between the tendon and the front of the tuberosity, and another bursa (bursa 
cubitalis interossea) is often interposed between the ulna and the tendon. As the 
tendon of the muscle approaches the radius it becomes twisted upon itself, so that 
its anterior surface becomes external and is applied to the tuberosity of the 
radius at its insertion: opposite the bend of the elbow the tendon gives off, from 
its inner side, a broad aponeurosis, the bicipital or semilunar fascia (lacertus 
fibrosus), which passes obliquely downward and inward across the brachial 
artery, and is continuous with the deep fascia of the forearm (Fig. 314). The 
inner border of this muscle forms a guide to the position of the vessel in tying the 
brachial artery in the middle of the arm.1 
Relations.-Its anterior surface is overlapped above by the Pectoralis major 
and Deltoid; in the rest of its extent it is covered by the superficial and deep 
fasciae and the integument. Its posterior surface rests above on the shoulder- 
joint and upper part of the humerus; below it rests on the Brachialis anticus, 
with the musculo-cutaneous nerve intervening between the two, and on the 
Supinator brevis. Its inner border is in relation with the Coraco-brachialis, and 
overlaps the brachial vessels and median nerve; its outer border, with the Deltoid 
and Supinator longus. 
The Brachialis Anticus (m. brachialis) is a broad muscle, which covers the elbow- 
joint and the lower half of the front of the humerus. It is somewhat compressed 
from before backward, and is broader in the middle than at either extremity. It 
arises from the lower half of the outer and inner surfaces of the shaft of the humerus, 
and commences above at the insertion of the Deltoid, which it embraces by two 
angular processes. Its origin extends below, to within an inch of the margin of 
the articular surface, and is limited on each side by the external and internal 
borders of the shaft of the humerus. It also arises from the intermuscular septa 
on each side, but more extensively from the inner than the outer, from which it is 
separated below by the Supinator longus and Extensor carpi radialis longior. Its 
fibres converge to a thick tendon, which is inserted into a rough depression on 
the anterior surface of the coronoid process of the ulna, being received into an 
interval between two fleshy slips of the Flexor profundus digitorum. 
Relations.-By its anterior surface, with the Biceps, the brachial vessels, mus- 
culo-cutaneous, and median nerves; by its posterior surface, with the humerus 
and front of the elbow-joint; by its inner border, with the Triceps, ulnar nerve, 
and Pronator radii teres, from which it is separated by the intermuscular septum; 
by its outer border, with the musculo-spiral nerve, radial recurrent artery, the 
Supinator longus, and Extensor carpi radialis longior. 
Nerves.-The muscles of this group are supplied by the musculo-cutaneous 
nerve. The Brachialis anticus usually receives an additional filament from the 
musculo-spiral. The Coraco-brachialis receives its supply primarily from the 
seventh cervical, the Biceps and Brachialis anticus from the fifth and sixth cer- 
vical nerves. 
Actions.-The Coraco-brachialis draws the humerus forward and inward, and 
at the same time assists in elevating it toward the scapula. The Biceps is a flexor 
of the forearm; it is also a powerful supinator, and serves to render tense the 
deep fascia of the forearm by means of the broad aponeurosis given off from 
1 A third head to the Biceps is occasionally found (Theile says as often as once in eight or nine subjects), 
arising at the upper and inner part of the Brachialis anticus, with the fibres of which it is continuous, and inserted 
into the bicipital fascia and inner side of the tendon of the Biceps. In most cases this additional slip passes 
behind the brachial artery in its course down the arm. Occasionally the third head consists of two slips which 
pass down, one in front, the other behind the artery, concealing the vessel in the lower half of the arm. THE POSTERIOR HUMERAL REGION 
477 
its tendon. The Brachialis anticus is a flexor of the forearm, and forms an impor- 
tant defence to the elbow-joint. When the forearm is fixed, the Biceps and 
Brachialis anticus flex the arm upon the forearm, as is seen in efforts at climbing. 
7. The Posterior Humeral Region 
Triceps. 
Subanconeus. 
The Triceps or the Triceps Extensor Cubiti (m. triceps brachii) (Fig. 317) is 
situated on the back of the arm, extending the entire length of the posterior surface 
of the humerus. It is of large size, and divided above into three parts; hence its 
name. These three portions have been named (1) the middle, scapular, or long head; 
(2) the external or long humeral head; and (3) the internal or short humeral head. 
The Middle, Long, or Scapular Head (caput longum) arises, by a flattened tendon, 
from a rough triangular depression on the scapula, immediately below the glenoid 
cavity, being blended at its upper part with the capsular ligament; the muscular 
fibres pass downward between the two other portions of the muscle, and join with 
them in the common tendon of insertion. 
The External Head (caput laterale) arises from the posterior surface of the shaft 
of the humerus, between the insertion of the Teres minor and the upper part of 
the musculo-spiral groove; from the external border of the humerus and the 
external intermuscular septum: the fibres from this origin converge toward the 
common tendon of insertion. 
The Internal Head (caput mediate) arises from the posterior surface of the shaft 
of the humerus, below the groove for the musculo-spiral nerve; commencing above, 
narrow and pointed, below the insertion of the Teres major, and extending to 
within an inch of the trochlear surface: it also arises from the internal border of 
the humerus, and from the back of the whole length of the internal and lower part 
of the external intermuscular septum. The fibres of this portion of the muscle are 
directed, some downward to the olecranon, whilst others converge to the common 
tendon of insertion. 
The Common Tendon of the Triceps commences about the middle of the back part 
of the muscle: it consists of two aponeurotic laminae, one of which is subcutaneous 
and covers the posterior surface of the muscle for the lower half of its extent; the 
other is more deeply seated in the substance of the muscle: after receiving the 
attachment of the muscular fibres, they join together above the elbow, and are 
inserted, for the most part, into the back part of the upper surface of the olecranon 
process; a band of fibres is, however, continued downward, on the outer side, 
over the Anconeus, to blend with the deep fascia of the forearm. A small bursa 
(bursa subtendinea olecrani) occasionally multilocular, is situated on the front part 
of this surface, beneath the tendon. The subcutaneous olecranon bursa (bursa sub- 
cutanea olecrani) is situated between the olecranon process and the skin. Within 
the tendon of the triceps is often found the bursa intratendinea olecrani. 
The long head of the Triceps descends between the Teres minor and Teres 
major, dividing the triangular space between these two muscles and the humerus 
into two smaller spaces, one triangular, the other quadrangular (Fig. 317). The 
triangular space contains the dorsalis scapulae vessels; it is bounded by the Teres 
minor above, the Teres major below, and the scapular head of the Triceps exter- 
nally: the quadrangular space transmits the posterior circumflex vessels and the 
circumflex nerve; it is bounded by the Teres minor above, the Teres major below, 
the scapular head of the Triceps internally, and the humerus externally. 
Relations.-By its posterior surface, with the Deltoid above: in the rest of its 
extent it is subcutaneous; by its anterior surface, with the humerus, musculo- 
spiral nerve, superior profunda vessels, and back part of the elbow-joint. Its 478 
THE MUSCLES AND FASCIAE 
middle or long head is in relation, behind, with the Deltoid and Teres minor; in 
front, with the Subscapularis, Latissimus dorsi, and Teres major. 
The Subanconeus (m. anconoeus) is a name given to a few fibres from the under 
surface of the lower part of the Triceps muscle, which are inserted into the posterior 
ligament of the elbow-joint. By some authors it is regarded as the analogue of 
the Subcrureus in the lower limb, but it is not a separate muscle. 
Nerves.-The Triceps is supplied by the seventh and eighth cervical nerves 
through the musculo-spiral nerve. 
Actions.-The Triceps is the great extensor muscle of the forearm, serving, 
when the forearm is flexed, to extend the elbow-joint. It is the direct antagonist 
of the Biceps and Brachialis anticus. When the arm is extended the long head 
of the muscles may assist the Teres major and Latissimus dorsi in drawing the 
humerus backward and in adducting it to the thorax. The long head of the Tri- 
ceps protects the under part of the shoulder-joint, and prevents displacement of 
the head of the humerus downward and backward. The Subanconeus draws 
up the posterior ligament during extension of the forearm. 
Surgical Anatomy.-The existence of the band of fibres from the Triceps to the fascia of 
the forearm is of importance in excision of the elbow, and should always be carefully preserved 
from injury by the operator, as by means of these fibres the patient is enabled to extend the 
forearm, a movement which would otherwise mainly be accomplished by gravity; that is to say, 
allowing the forearm to drop from its own weight. 
Dissection.-To dissect the forearm, place the limb in the position indicated in Fig. 312, 
make a vertical incision along the middle line from the elbow to the wrist, and a transverse 
incision at the extremity of this; the superficial structures being removed, the deep fascia of 
the forearm is exposed. 
III. MUSCLES AND FASCIA OF THE FOREARM. 
Deep Fascia {fascia antibrachii).-The deep fascia of the forearm, continuous 
above with that enclosing the arm, is a dense, highly glistening aponeurotic 
investment, which forms a general sheath enclosing the muscles in this region; 
it is attached, behind, to the olecranon and posterior border of the ulna, and gives 
off from its inner surface numerous intermuscular septa, which enclose each mus- 
cle separately. Below, it is continuous in front with the anterior annular ligament 
(ligamentum carpi volare), and forms a sheath for the tendon of the Palmaris longus 
muscle, which passes over the annular ligament to be inserted into the palmar 
fascia. Behind, near the wrist-joint, it becomes much thickened by the addition 
of many transverse fibres, and forms the posterior annular ligament (ligamentum 
carpi dorsale). It consists of circular and oblique fibres, connected together by 
numerous vertical fibres. It is much thicker on the dorsal than on the palmar sur- 
face, and at the lower than at the upper part of the forearm, and is strengthened 
above by tendinous fibres derived from the Brachialis anticus and Biceps in front, 
and from the Triceps behind. Its deep surface gives origin to muscular fibres, 
especially at the upper part of the inner and outer sides of the forearm, and forms 
the boundaries of a series of conical-shaped cavities, in which the muscles are 
contained. Besides the vertical septa separating each muscle, transverse septa are 
given off on the anterior and posterior stirfaces of the forearm, separating the 
deep from the superficial layer of muscles. Numerous apertures exist in the fascia 
for the passage of vessels and nerves; one of these, of large size, situated at the 
front of the elbow, serves for the passage of a communicating branch between 
the superficial and deep veins. 
The muscles of the forearm may be subdivided into groups corresponding to 
the region they occupy. One group occupies the inner and anterior aspect of the 
forearm, and comprises the Flexor and Pronator muscles. Another group occupies 
its outer side, and a third its posterior aspect. The two latter groups include all 
the Extensor and Supinator muscles. THE ANTERIOR RADIO-ULNAR REGION 
479 
8. The Anterior Radio-ulnar Region. 
The muscles in this region are divided for convenience of description into two 
groups or layers, superficial and deep. 
The Superficial Layer. 
Pronator radii teres. 
Flexor carpi radialis. 
Palmaris longus. 
Flexor carpi ulnaris. 
These muscles take origin from the internal condyle of the humerus by a 
common tendon. 
The Pronator Radii Teres (m. pronator teres} arises by two heads. One, the 
larger and more superficial, humeral head (caput humerale}, arises from the humerus, 
immediately above the internal condyle, and from the tendon common to the 
origin of the other muscles; also from the fascia of the forearm and the inter- 
muscular septum between it and the Flexor carpi radialis. The other head, the 
ulnar head {caput ulnare), is a thin fasciculus which arises from the inner side of 
the coronoid process of the ulna, joining the preceding at an acute angle. 
Between the two heads the median nerve enters the forearm. The muscle passes 
obliquely across the forearm from the inner to the outer side, and terminates in a 
fiat tendon, which turns over the outer margin of the radius, and is inserted into 
a rough impression at the middle of the outer surface of the shaft of that bone. 
Relations.-By its anterior surface, throughout the greater part of its extent, 
with the deep fascia; at its insertion it is crossed by the radial vessels and nerve, 
and is covered by the Supinator longus; by its posterior surface, with the Brachialis 
anticus, Flexor sublimis digitorum, the median nerve, and ulnar artery, the small 
or deep head being interposed between the two latter structures. Its outer border 
forms the inner boundary of a triangular space in which are placed the brachial 
artery, median nerve, and tendon of the Biceps muscle. Its inner border is in 
contact with the Flexor carpi radialis. 
Flexor sublimis digitorum. 
Surgical Anatomy.-This muscle, when suddenly brought into very active use, as in the 
game of lawn tennis, is apt to be strained, producing slight swelling and tenderness, and pain 
on putting the muscle into action. This is known as lawn-tennis arm. 
The Flexor Carpi Radialis lies on the inner side of the preceding muscle. It 
arises from the internal condyle by the common tendon, from the fascia of the fore- 
arm, and from the intermuscular septa between it and the Pronator radii teres, on 
the outside, the Palmaris longus internally, and the Flexor sublimis digitorum 
beneath. Slender and aponeurotic in structure at its commencement, it increases 
in size, and terminates in a tendon which forms rather more than the lower half 
of its length. This tendon passes through a canal on the outer side of the annular 
ligament, runs through a groove in the os trapezium (which is converted into a 
canal by a fibrous sheath, and is lined by a synovial membrane), and is inserted 
into the base of the metacarpal bone of the index finger, and by a slip into the base 
of the metacarpal bone of the middle finger. The radial artery lies between the 
tendon of this muscle and the Supinator longus, and may easily be tied in this 
situation. In the hand a bursa (bursa m. flexoris carpi radialis) lies between the 
base of the second metacarpal bone and the tendon (Spalteholz). 
Relations.-By its superficial surface, with the deep fascia and the integument; 
by its deep surface, with the Flexor sublimis digitorum, Flexor longus pollicis, 
and wrist-joint; by its outer border, with the Pronator radii teres and the radial 
vessels; by its inner border, with the Palmaris longus above and the median 
nerve below. 480 
THE MUSCLES AND EASULE 
1 he Palmaris Longus (Fig. 318) is a slender, fusiform muscle lying on the inner 
side of the preceding. It arises from the inner condyle of the humerus by the com- 
mon tendon, from the deep fascia, and the inter- 
muscular septa between it and the adjacent mus- 
cles. It terminates in a slender flattened tendon, 
which passes over the upper part of the annular 
ligament, to end in the central part of the palmar 
fascia and lower part of the annular ligament, 
frequently sending a tendinous slip to the short 
muscles of the thumb. This muscle is often 
absent, and is subject to very considerable varia- 
tions; it may be tendinous above and muscular 
below; or it may be muscular in the centre, with 
a tendon above and below; or it may present two 
muscular bundles with a central tendon; or 
finally it may consist simply of a mere tendinous 
band. 
Relations.-By its superficial surface, with the 
deep fascia. By its deep surface, with the Flexor 
sublimis digitorum. Internally, with the Flexor 
carpi ulnaris. Externally, with the Flexor carpi 
radialis. The median nerve lies close to the 
tendon, just above the wrist, on its inner and 
posterior side. 
The Flexor Carpi Ulnaris (Fig. 318) lies along 
the ulnar side of the forearm. It arises by two 
heads, connected by a tendinous arch, beneath 
which pass the ulnar nerv§ and posterior ulnar 
recurrent artery. One head arises from the inner 
condyle of the humerus, humeral head {caput 
humerale), by the common tendon; the other from 
the inner margin of the olecranon and from the 
upper two-thirds of the posterior border of the 
ulna, ulnar head {caput ulnare), by an aponeu- 
rosis, common to it and the Extensor carpi 
ulnaris and Flexor profundus digitorum; and from 
the intermuscular septum between it and the 
Flexor sublimis digitorum. The fibres terminate 
in a tendon which occupies the anterior part of 
the lower half of the muscle, and is inserted into 
the pisiform bone, and is prolonged from this to 
the fifth metacarpal and unciform bones, by the 
piso-metacarpal and piso-uncinate ligaments: it is 
also attached by a few fibres to the annular liga- 
ment. The ulnar artery lies on the outer side of 
the tendon of this muscle, in the lower two-thirds 
of the forearm, the tendon forming a guide in tying the vessel in this situation. 
A bursa {bursa m. flexoris carpi ulnaris) is placed between the tendon and a 
part of the pisiform bone. 
Relations.-By its superficial surface, with the deep fascia, with which it is 
intimately connected for a considerable extent; by its deep surface, with the Flexor 
sublimis digitorum, the Flexor profundus digitorum, the Pronator quadratus, and 
the ulnar vessels and nerve; by its outer or radial border, with the Palmaris longus 
above and the ulnar vessels and nerve below. 
Fig. 318.-Front of the left forearm. 
Superficial muscles. THE ANTERIOR RADIO-ULNAR REGION 
481 
Ihe Flexor Subhmis Digitorum (m. flexor digitorum sublimis) (Fig. 318) 
is placed beneath the preceding muscles, which therefore must be removed 
in order to bring its attachment into view. It is the largest of the muscles of the 
superficial layer, and arises by three heads. One head, the humeral head (caput 
humerale), arises from the internal condyle of the humerus by the common ten- 
don, from the internal lateral ligament of the elbow-joint, and from the intermus- 
cular septum common to it and the preceding muscles. The second head, ulnar 
head (caput ulnare), arises from the inner side of the coronoid process of the ulna, 
above the ulnar origin of the Pronator radii teres (Fig. 133, p. 185). The third 
head, radial head (caput radiale), arises from the oblique line of the radius, extend- 
ing from the tubercle to the insertion of the Pronator radii teres. The fibres pass 
vertically downward, forming a broad and thick muscle, which speedily divides into 
two planes of muscular fibres, superficial and deep: the superficial plane divides 
into two parts which end in tendons for the middle and ring fingers; the deep 
plane also divides into two parts, which end in tendons for the index and little 
fingers, but previously to having done so it gives off a muscular slip, which joins 
that part of the superficial plane which is intended for the ring finger. As the 
four tendons thus formed pass beneath the annular ligament into the palm of the 
hand, they are arranged in pairs, the superficial pair corresponding to the middle 
and ring fingers, the deep pair to the index and little fingers. The tendons diverge 
from one another as they pass onward. Opposite the bases of the first phalanges 
each tendon divides into two slips (chiasma tendinum') to allow of the passage of 
the corresponding tendon of the Flexor profundus digitorum; the two portions of 
the tendon then unite and form a grooved channel for the reception of the accom- 
panying deep flexor tendon. Finally they subdivide a second time, to be inserted 
into the sides of the second phalanges 
about their middle. The insertion in the 
index finger is shown in Fig. 324. After 
leaving the palm the tendons of the 
superficial flexor, accompanied by the deep 
flexor tendons, lie in osseo-aponeurotic 
canals (Fig. 320). Each canal or theca 
extends from the metacarpo-phalangeal 
articulation to the proximal end of the 
distal phalanx (Fig. 231). It is formed 
by strong fibrous bands, which arch across 
the tendons, and are attached on each side 
to the margins of the phalanges. Oppo- 
site the middle of the proximal and second 
phalanges the sheath is very strong, and 
the fibres pass transversely; but opposite the joints it is much thinner, and the 
fibres pass obliquely. It is very thin over the metacarpo-phalangeal articulation. 
It is absent over the distal phalanx. Each sheath is lined by a synovial mem- 
brane, which is reflected on the contained tendons. 
Relations.-In the forearm, by its superficial surface, with the deep fascia and 
all the preceding superficial muscles; by its deep surface, with the Flexor profundus 
digitorum, Flexor longus pollicis, the ulnar vessels and nerve, and the median 
nerve. In the hand its tendons are in relation, in front, with the palmar fascia, 
superficial palmar arch, and the branches of the median nerve; behind, with the 
tendons of the deep Flexor and the Lumbricales. 
FLEXOR PROFUNDUS 
DIGITORUM 
SHEATH OR 
flexor' 
TENDONS 
FLEXOR 
SUBLI MIS 
DIGITORUM 
DIGITAL 
ARTERIES 
AND NERVES 
COMMON TENDON OF 
EXTENSOR MUSCLE 
OF FINGERS 
Fig. 319. - Section passing through the middle 
third of the first phalanx of the middle finger (frozen 
section). The tendon of the Flexor sublimis digi- 
torum is divided into two small bands, which spread 
laterally and engage themselves between the osse- 
ous plane and the Flexor profundus digitorum. 
(Poirier and Charpy.) 
FIRST PHALANX 482 
THE MUSCLES AND FASCIAE 
The Deep Layer (Fig. 320). 
Flexor profundus digitorum. Flexor longus pollicis. 
Pronator quadratus. 
Dissection.-Divide each of the superficial muscles at its centre, and turn either end aside; 
the deep layer of muscles, together with the median nerve and ulnar vessels, will then be exposed. 
The Flexor Profundus Digitorum (m. flexor digitorum profundus) (Fig. 320) 
is situated on the ulnar side of the forearm, immediately beneath the superficial 
Flexors. It arises from the upper three-fourths of the anterior and inner 
surfaces of the shaft of the ulna, embracing the insertion of the Brachialis anticus 
above, and extending, below, to within a short distance of the Pronator quadratus. 
It also arises from a depression on the inner side of the coronoid process; by an apo- 
neurosis from the upper three-fourths of the posterior border of the ulna, in common 
with the Flexor and Extensor carpi ulnaris; and from the ulnar half of the inter- 
osseous membrane. The fibres form a fleshy belly of considerable size, which divides 
into four tendons: these pass under the annular ligament beneath the tendons of the 
Flexor subliinis digitorum. Opposite the first phalanges the tendons pass through 
the openings in the two slips of the tendons of the Flexor sublimis digitorum, and 
are finally inserted into the bases of the last phalanges. The portion of the muscle 
for the index finger (Fig. 324) is usually distinct throughout, but the tendons for 
the three inner fingers are connected together by cellular tissue and tendinous slips 
as far as the palm of the hand. The tendons of this muscle and those of the Flexor 
sublimis digitorum, whilst contained in the osseo-aponeurotic canals of the fingers, 
are invested in a synovial sheath, and are connected to each other and to the 
phalanges by slender tendinous filaments, called vincula accessoria tendinum (vin- 
culum tendinum). One of these connects the deep tendon to the bone before it 
passes through the superficial tendon; a second connects the two tendons together, 
after the deep tendons have passed through; and a third connects the deep ten- 
don to the head of the second phalanx. This last consists largely of yellow elastic 
tissue, and may assist in drawing down the tendon after flexion of the finger.1 
Four small muscles, the Lumbricales, are connected with the tendons of the Flexor 
profundus in the palm. They will be described with the muscles in that region. 
Relations.-By its superficial surface, in the forearm, with the Flexor sublimis 
digitorum, the Flexor carpi ulnaris, the ulnar vessels and nerve, and the median 
nerve; and in the hand, with the tendons of the superficial Flexor; by its deep 
surface, in the forearm, with the ulna, the interosseous membrane, the Pronator 
quadratus; and in the hand, with the Interossei, Adductor pollicis, and deep 
palmar arch; by its ulnar border, with the Flexor carpi ulnaris; by its radial border, 
with the Flexor longus pollicis, the anterior interosseous vessels and nerve being 
interposed. 
The Flexor Longus Pollicis (m. flexor pollicis longus) (Fig. 320) is situated on 
the radial side of the forearm, lying on the same plane as the preceding. It arises 
from the grooved anterior surface of the shaft of the radius, commencing above, 
immediately below the tuberosity and oblique line, and extending below to within 
a short distance of the Pronator quadratus. It also arises from the adjacent part 
of the interosseous membrane and generally by a fleshy slip from the inner border 
of the coronoid process or from the internal condyle of the humerus. The fibres 
pass downward, and terminate in a flattened tendon which passes beneath the 
annular ligament, is then lodged in the interspace between the outer head of the 
Flexor brevis pollicis and the Adductor obliquus pollicis, and, entering an osseo- 
aponeurotic canal similar to those for the other flexor tendons, is inserted into the 
base of the last phalanx of the thumb. 
1 Marshall, Brit, and For. Med -Chir. Rev., 1853. THE ANTERIOR RADIO-ULNAR REGION 
483 
Relations.-By its superficial sur- 
face, with the Flexor sublimis digi- 
torum, Flexor carpi radialis, Supi- 
nator longus, and radial vessels; by 
its deep surface, with the radius, 
interosseous membrane, and Pro- 
nator quadratus; by its ulnar border, 
with the Flexor profundus digitorum, 
from which it is separated by the 
anterior interosseous vessels and 
nerve. 
The Pronator Quadratus (Figs. 
320 and 329) is a small, flat, quadri- 
lateral muscle, extendingtransversely 
across the front of the radius and 
ulna, above their carpal extremities. 
It arises from the oblique or pronator 
ridge on the lower part of the ante- 
rior surface of the shaft of the ulna; 
from the lower fourth of the anterior 
surface and the anterior border of 
the ulna; and from a strong aponeu- 
rosis which covers the inner third of 
the muscle. The fibres pass out- 
ward and slightly downward, to be 
inserted into the lower fourth of the 
anterior surface and anterior border 
of the shaft of the radius. 
Relations.-By its superficial sur- 
face, with the Flexor profundus digi- 
torum, the Flexor longus pollicis, 
Flexor carpi radialis, and the radial 
vessels; by its deep surface, with the 
radius, ulna, and interosseous mem- 
brane. 
Nerves. - All the muscles of the 
superficial layer are supplied by the 
median nerve, excepting the Flexor 
carpi ulnaris, which is supplied by the 
ulnar nerve. The Pronator radii teres 
and the Flexor carpi radialis derive 
their supply primarily from the sixth 
cervical; the Palmaris longus from 
the eighth cervical; the Flexor sub- 
limis digitorum from the seventh and 
eighth cervical and first dorsal, and 
the Flexor carpi ulnaris from the 
eighth cervical and first dorsal nerves. 
Of the deep layer, the Flexor pro- 
fundus digitorum is supplied by the 
eighth cervical and first dorsal 
through the ulnar and anterior in- 
terosseous branch of the median. 
The remaining two muscles, the 
Fig. 320.-Front of the left forearm. Deep muscles. 484 
THE MUSCLES AND FASCINE 
Flexor longus pollicis and Pronator quadratus, are also supplied by the eighth 
cervical and first dorsal through the anterior interosseous branch of the median. 
Actions.-These muscles act upon the forearm, the wrist, and hand. The 
Pronator radii teres helps to rotate the radius upon the ulna, rendering the hand 
prone: when the radius is fixed it assists the other muscles in flexing the forearm. 
The Flexor carpi radialis is one of the flexors of the wrist; when acting alone it 
flexes the wrist, inclining it to the radial side. It can also assist in pronating the 
forearm and hand, and, by continuing its action, in bending the elbow. The Flexor 
carpi ulnaris is one of the flexors of the wrist: when acting alone it flexes the wrist, 
inclining it to the ulnar side (adducts the wrist), and, by continuing to contract, 
it bends the elbow. The Palmaris longus is a tensor of the palmar fascia, and 
tension of this fascia protects the parts beneath it. It also assists in flexing the 
wrist and elbow. The Flexor sublimis digitorum flexes the middle phalanx and 
then assists in flexing the wrist and elbow. The Flexor profundus digitorum is 
the flexor of the distal phalanx. After the Flexor sublimis has bent the second 
phalanx, the Flexor profundus flexes the terminal one, but it cannot do so until 
after the contraction of the superficial muscle. After flexing the distal phalanx, 
it assists in flexing the middle phalanx, the proximal phalanx, and the wrist. The 
Flexor longus pollicis is the flexor of the distal phalanx of the thumb. When the 
thumb is fixed it also assists in flexing the wrist. The Pronator quadratus helps 
to rotate the radius upon the ulna, rendering the hand prone. 
Surgical Anatomy.-When a finger is amputated so that the fibrous sheath of the flexor ten- 
dons is divided in a region in which it is firm and dense, the tendon contracts but the theca does 
not, and the rigid theca constitutes a permeable passage to the palm. If the parts should be 
infected the theca will draw pus toward the palm. Hence it is best to close the theca by sutures. 
"Over the terminal phalanx, and over the joint between the middle and terminal phalanges, 
there is no fibrous sheath. In front of the metacarpo-phalangeal joint it is scarcely evident. 
Over the first and second (proximal and middle) phalanges, and in front of the joint between 
these bones, the fibrous sheath is well marked, and appears as a rigid tube when cut across. 
As the sheath crosses the metacarpo-phalangeal and first interphalangeal joints, it is adherent 
to the glenoid ligament, and is easily closed by two fine catgut sutures passed vertically-i. e., 
from the dorsal to the palmar wall. Opposite the shafts of the first and second phalanges, 
however, there is much difficulty in effecting closure, since the sheath is united to the periosteum, 
and that membrane is very thin. In these situations the periosteum should be stripped up a 
little from the palmar aspect of the bone, and the orifice of the tube secured by two fine sutures 
passed either vertically or transversely, as may appear the more convenient. This stripping 
off of periosteum should be effected before the bone is divided."1 
9. The Radial Region (Figs. 318,321,322). 
Supinator longus. Extensor carpi radialis longior. 
Extensor carpi radialis brevior. 
Dissection.-Divide the integument in the same manner as in the dissection of the anterior 
brachial region, and, after having examined the cutaneous vessels and nerves and deep fascia, 
remove all those structures. The muscles will then be exposed. The removal of the fascia 
will be considerably facilitated by detaching it from below upward. Great care should be 
taken to avoid cutting across the tendons of the muscles of the thumb, which cross obliquely 
the larger tendons running down the back of the radius. 
The Supinator Longus (m. brachioradialis} (Fig. 318) is the most superficial 
muscle on the radial side of the forearm; it is fleshy for the upper two-thirds of 
its extent, tendinous below. It arises from the upper two-thirds of the external 
supracondylar ridge of the humerus, and from the external intermuscular septum, 
being limited above by the musculo-spiral groove. The fibres terminate above 
the middle of the forearm in a flat tendon, which is inserted into the outer side 
of the base of the styloid process of the radius. 
1 Operative Surgery. By Sir Frederick Treves. THE RADIAL REGION 
485 
Relations.-By its superficial sur- 
face, with the integument and fascia 
for the greater part of its extent; near 
its insertion it is crossed by the Ex- 
tensor ossis metacarpi pollicis and the 
Extensor brevis pollicis; by its deep 
surface, with the humerus, the Ex- 
tensor carpi radialis longior and bre- 
vior, the insertion of the Pronator 
radii teres, and the Supinator brevis; 
by its inner border, above the elbow, 
with the Brachialis anticus, the mus- 
culo-spiral nerve, and the radial recur- 
rent artery; and in the forearm with 
the radial vessels and nerve. 
The Extensor Carpi Radialis 
Longior (m. extensor carpi radialis 
longus) (Fig. 321) is placed partly 
beneath the preceding muscle. It 
arises from the lower third of the ex- 
ternal supracondylar ridge of the 
humerus, and from the external in- 
termuscular septum by a few fibres 
from the common tendon of origin of 
the Extensor muscles of the forearm. 
The fibres terminate at the upper third 
of the forearm in a flat tendon, which 
runs along the outer border of the 
radius, beneath the extensor tendons 
of the thumb; it then passes through 
a groove common to it and the Ex- 
tensor carpi radialis brevior, immedi- 
ately behind the styloid process, and 
is inserted into the base of the meta- 
carpal bone of the index finger, on 
its radial side. 
Relations.-By its superficial sur- 
face, wit^ the Supinator longus and 
fascia of the forearm; its outer side 
is crossed obliquely by the extensor 
tendons of the thumb; by its deep 
surface, with the elbow-joint, the 
Extensor carpi radialis brevior, and 
back part of the wrist. 
The Extensor Carpi Radialis 
Brevior (m. extensor carpi radialis 
brevis) (Fig. 321) is shorter, as its 
name implies, and thicker than the 
preceding muscle, beneath which it is 
placed. It arises from the external 
condyle of the humerus by a tendon 
common to it and the three following 
muscles; from the external lateral 
ligament of the elbow-joint, from a 
strong aponeurosis which covers its 
Fig. 321.-Posterior surface of the forearm. Superficial 
muscles. 486 
TILE MUSCLES AND FASCIAE 
surface, and from the intermuscular septa between it and the adjacent muscles. 
The fibres terminate about the middle of the forearm in a flat tendon which is 
closely connected with that of the preceding muscle, and accompanies it to the 
wrist, lying in the same groove on the posterior surface of the radius; it passes 
beneath the extensor tendons of the thumb, then beneath the annular ligament, 
and, diverging somewhat from its fellow, is inserted into the base of the meta- 
carpal bone of the middle finger, on its radial side. There is often a bursa 
(bursa m. extensoris carpi radialis brevis) between a portion of the base of the 
bone and the tendon. 
The tendons of the two preceding muscles pass through the same compartment 
of the annular ligament, and are lubricated by a single synovial membrane, but are 
separated from each other by a small vertical ridge of bone as they lie in the groove 
at the back of the radius. 
Relations.-By its superficial surface, with the Extensor carpi radialis longior, 
and with the Extensor muscles of the thumb which cross it; by its deep surface, 
with the Supinator brevis, tendon of the Pronator radii teres, radius, and wrist- 
joint; by its ulnar border, with the Extensor communis digitorum. 
The muscles in this region are divided for purposes of description into two 
groups or layers, superficial and deep. 
10. The Posterior Radio-ulnar Region (Fig. 321). 
The Superficial Layer. 
Extensor communis digitorum. 
Extensor minimi digiti. 
Extensor carpi ulnaris 
Anconeus. 
The Extensor Communis Digitorum (m. extensor digitorum communis) is 
situated at the back part of the forearm. It arises from the external condyle of 
the humerus by the common tendon, from the deep fascia, and the intermus- 
cular septa between it and the adjacent muscles. Just below the middle of 
the forearm it divides into three fleshy masses, from which tendons proceed; 
these pass, together with the Extensor indicis, through a separate compartment 
of the annular ligament, lubricated by a synovial membrane. The tendons 
then diverge, the innermost one dividing into two; and all, after passing across the 
back of the hand, are inserted into the second and third phalanges of the fingers in 
the following manner: the outermost tendon, accompanied by the Extensor indicis, 
goes to the index finger (Figs. 321, 323, and 324); the second tendon is sometimes 
connected to the first by a thin transverse band, and receives a slip from the third 
tendon (Fig. 321); it goes to the middle finger; the third tendon gives off the slip 
to the second (Fig. 321), and receives a very considerable part of the fourth tendon; 
the fourth, or innermost tendon, divides into two parts: one goes to join the third 
tendon; the other, reinforced by the Extensor minimi digiti, goes to the little 
finger. Each tendon opposite the metacarpo-phalangeal articulation becomes 
narrow and thickened, and gives off a thin fasciculus upon each side of the joint, 
which blends with the lateral ligaments and serves as the posterior ligament; 
after having passed the joint it spreads out into a broad aponeurosis, which covers 
the whole of the dorsal surface of the first phalanx, being reinforced, in this 
situation, by the tendons of the Interossei and Lumbricales. Opposite the first 
phalangeal joint this aponeurosis divides into three slips, a middle and two 
lateral: the former is inserted into the base of the second phalanx; and the two 
lateral, which are continued onward along the sides of the second phalanx, unite 
by their contiguous margins, and are inserted into the dorsal surface of the last 
phalanx. As the tendons cross the phalangeal joints they furnish them with pos- 
terior ligaments. The accessory slips or lateral vincula which join the tendon THE POSTERIOR RADIO-ULNAR REGION 
487 
of the ring finger to the tendon of the little finger and the tendon of the middle 
finger are constant. If the middle and little fingers are held flexed the lateral 
vincula greatly limit the range of extension possible in the ring finger-a limi- 
tation which interferes with a piano-player (Prof. William S. Forbes). 
Relations.-By its superficial surface, with the fascia of the forearm and hand, 
the posterior annular ligament, and integument; by its deep surjace, with the 
Supinator brevis, the Extensor muscles of the thumb and index finger, the pos- 
terior interosseous vessels and nerve, the wrist-joint, carpus, metacarpus, and 
phalanges; by its radial border, with the Extensor carpi radialis brevior; by its 
ulnar border, with the Extensor minimi digiti and Extensor carpi ulnaris. 
'The Extensor Minimi Digiti (m. extensor digiti quinti proprius) is a slender 
muscle placed on the inner side of the Extensor communis, with which it is gen- 
erally connected. It arises from the common tendon by a thin, tendinous slip, and 
from the intermuscular septa between it and the adjacent muscles. Its tendon 
runs through a separate compartment in the annular ligament behind the inferior 
radio-ulnar joint, then divides into two as it crosses the hand, the outermost 
division being joined by the slip from the innermost tendon of the common exten- 
sor. The two slips thus formed spread into a broad aponeurosis, which after 
receiving a slip from the Abductor minimi digiti is inserted into the second and 
third phalanges. The tendon is situated on the ulnar side of, and somewhat more 
superficial than, the common extensor. 
The Extensor Carpi Ulnaris is the most superficial muscle on the ulnar side of 
the forearm. It arises from the external condyle of the humerus by the common 
tendon; by an aponeurosis from the posterior border of the ulna in common 
with the Flexor carpi ulnaris and the Flexor profundus digitorum; and from the 
deep fascia of the forearm. This muscle terminates in a tendon which runs 
through a groove behind the styloid process of the ulna, passes through a separate 
compartment in the annular ligament, and is inserted into the prominent tubercle 
on the ulnar side of the base of the metacarpal bone of the little finger. 
Relations.-By its superficial surface, with the deep fascia of the forearm; by 
its deep surface, with the ulna and the muscles of the deep layer. 
The Anconeus (m. anconceus) is a small triangular muscle placed behind and 
below the elbow-joint, and appears to be a continuation of the external portion of 
the Triceps. It arises by a separate tendon from the back part of the outer condyle 
of the humerus, and is inserted into the side of the olecranon and upper fourth of 
the posterior surface of the shaft of the ulna; its fibres diverge from their origin, 
the upper ones being directed transversely, the lower obliquely inward. 
Relations.-By its superficial surface, with a strong fascia derived from the 
Triceps; by its deep surface, with the elbow-joint, the orbicular ligament, the 
ulna, and a small portion of the Supinator brevis. 
The Deep Layer (Fig. 323) 
Supinator radii brevis. 
Extensor ossis metacarpi pollicis. 
Extensor brevis pollicis. 
Extensor longus pollicis. 
Extensor indicis 
The Supinator Radii Brevis (nt. supinator) (Figs. 322 and 323) is a broad muscle, 
of hollow cylindrical form, curved round the upper third of the radius. It consists of 
two distinct planes of muscular fibres, between which lies the posterior interosseous 
nerve (Fig. 322). The two planes arise in common: the superficial one by tendin- 
ous, and the deeper by muscular, fibres from the external condyle of the humerus; 
from the external lateral ligament of the elbow-joint and the orbicular ligament of 
the radius; from the ridge on the ulna, which runs obliquely downward from the 488 
THE MUSCLES AND FASCIAE 
posterior extremity of the lesser sigmoid cavity; from the triangular depression in 
front of it; and from a tendinous expansion which covers the surface of the muscle. 
Ini. 
Condyle." 
.Olecranon. 
Coronoid 
proc. 
Head of 
radius.' 
TENDON OF. 
BICEPS. 
Fig. 322.-Supinator brevis. (From a prepa- 
ration in the Museum of the Royal College of 
Surgeons of England.) 
The superficial fibres surround the 
upper part of the radius, and are in- 
serted intothe outer edge of the bicip- 
ital tuberosity and into the oblique 
line of the radius, as low down as the 
insertion of the Pronator radii teres. 
The upper fibres of the deeper plane 
form a sling-like fasciculus, which 
encircles the neck of the radius 
above the tuberosity and is at- 
tached to the back part of its inner 
surface: the greater part of this por- 
tion of the muscle is inserted into 
the posterior and external surface 
of the shaft, midway between the 
oblique line and the head of the bone. Between the insertion of the two 
planes the posterior interosseous nerve lies on the shaft of the bone (Fig. 322). 
EXTENSOR 
CARPI ULNARIS 
Fig. 323.-Posterior surface of the forearm. Deep muscles. THE POSTERIOR RADIO-ULNAR REGION 
489 
Relations.-By its superficial surface, with the superficial Extensor and Supina- 
tor muscles, and the radial vessels and nerve; by its deep surface, with the elbow- 
joint, the interosseous membrane, and the radius. 
The Extensor Ossis Metacarpi Pollicis (m. abductor pollicis longus) is the most 
external and the largest of the deep extensor muscles: it lies immediately below 
the Supinator brevis, with which it is sometimes united. It arises from the outer 
part of the posterior surface of the shaft of the ulna below the insertion of the 
Anconeus, from the interosseous membrane, and from the middle third of the 
posterior surface of the shaft of the radius. Passing obliquely downward and 
outward, it terminates in a tendon which runs through a groove on the outer side 
of the styloid process of the radius, accompanied by the tendon of the Extensor 
brevis pollicis, and is inserted into the base of the metacarpal bone of the thumb. 
It occasionally gives off two slips near its insertion-one to the Trapezium, and the 
other to blend with the origin of the Abductor pollicis. 
Relations.-By its superficial surface, with the Extensor communis digitorum, 
Extensor minimi digiti, and fascia of the forearm, and with the branches of the 
posterior interosseous artery and nerve which cross it; by its deep surface, with 
the ulna, interosseous membrane, radius, the tendons of the Extensor carpi radialis 
longior and brevior, which it crosses obliquely, and, at the outer side of the wrist, 
with the radial vessels; by its upper border, with the Supinator brevis; by its 
lower border, with the Extensor brevis pollicis. 
The Extensor Brevis Pollicis, often called the extensor primi internodii pollicis 
(m. extensor pollicis brevis), the smallest muscle of this group, lies on the inner 
side of the preceding. It arises from the posterior surface of the shaft of the radius, 
below the Extensor ossis metacarpi 
pollicis, and from the interosseous 
membrane. Its direction is similar to 
that of the Extensor ossis metacarpi 
pollicis, its tendon passing through the 
same groove on the outer side of the 
styloid process, to be inserted into the 
base of the first phalanx of the thumb. 
Relations.-The same as those of 
the Extensor ossis metacarpi pollicis. 
The Extensor Longus Pollicis, 
often called the extensor secundi inter- 
nodii pollicis (m. extensor pollicis longus) 
is much larger than the preceding 
muscle, the origin of which it partly 
covers in. It arises from the outer 
part of the posterior surface of the 
shaft of the ulna, below the origin of 
the Extensor ossis metacarpi pollicis, 
and from the interosseous membrane. 
It terminates in a tendon which passes 
through a separate compartment in 
the annular ligament, lying in a nar- 
row, oblique groove at the back part 
of the lower end of the radius. It then crosses obliquely the tendons of the 
Extensor carpi radialis longior and brevior, being separated from the other 
extensor tendons of the thumb by a triangular interval, in which the radial artery 
is found, and is finally inserted into the base of the last phalanx of the thumb. 
Relations.-By its superficial surface, with the same parts as the Extensor ossis 
metacarpi pollicis; by its deep surface, with the ulna, interosseous membrane, the 
LIGAMENTUM 
BREVIS 
LIGAMENTUM 
LONGUS 
LIGAMENTUM BREVIS 
FLEXOR SUBLIMIS 
DIGITORUM 
EXPANSION OF 
EXTENSOR TENDON 
FLEXOR PROFUNDUS 
DIGITORUM 
FIRST LUMBRICAL 
MUSCLE 
FIRST DORSAL 
INTEROSSEOUS 
MUSCLE 
EXTENSOR INDICIS 
TENDON 
EXTENSOR COMMUNIS 
DIGITORUM TENDON 
Fig. 324.-The tendons attached to the index finger. 
(Cunningham.) 490 
THE MUSCLES AND FASCIAE 
posterior interosseous nerve, radius, the wrist, the radial vessels, and metacarpal 
bone of the thumb. 
The Extensor Indicis (m. extensor indicts proprius) (Figs. 321, 323, and 324) is 
a narrow, elongated muscle placed on the inner side of, and parallel with, the 
preceding. It arises from the posterior surface of the shaft of the ulna, below 
the origin of the Extensor longus pollicis and from the interosseous membrane. 
Its tendon passes with the Extensor communis digitorum through the same canal 
in the annular ligament, and subsequently joins the tendon of the Extensor 
communis which belongs to the index finger, opposite the lower end of the 
corresponding metacarpal bone, lying to the ulnar side of the tendon from the 
common extensor. 
Relations.-The relations are similar to those of the preceding muscles. 
Nerves.-The Supinator longus js supplied by the sixth, the Extensor carpi 
radialis longior by the sixth and seventh, and the Anconeus by the seventh and 
eighth cervical nerves, all through the musculo-spiral nerve; the remaining muscles 
of the radial and posterior brachial region are supplied through the posterior 
interosseous nerve, the Supinator brevis being supplied by the sixth cervical, the 
Extensor carpi radialis brevior by the sixth and seventh cervical, and all the other 
muscles by the seventh cervical. 
Actions.-The muscles of the radial and posterior brachial regions, which 
comprise all the extensor and supinator muscles, act upon the forearm, wrist, and 
hand; they are the direct antagonists of the pronator and flexor muscles. The 
Anconeus assists the Triceps in extending the forearm. The chief action of the 
Supinator longus is that of a flexor of the elbow-joint, but in addition to this it 
may act both as a supinator or a pronator; that is to say, if the forearm is forcibly 
pronated it will act as a supinator, and bring the bones into a position midway 
between supination and pronation; and vice versa, if the arm is forcibly supinated, 
it will act as a pronator, and bring the bones into the same position, midway 
between supination and pronation. The action of the muscle is therefore to throw 
the forearm and hand into the position they naturally occcupy when placed across 
the chest. The Supinator brevis is a supinator; that is to say, when the radius 
has been carried across the ulna in pronation and the back of the hand is directed 
forward, this muscle carries the radius back again to its normal position on the 
outer side of the ulna, and the palm of the hand is again directed forward. The 
Extensor carpi radialis longior extends the wrist and abducts the hand. It may 
also assist in bending the elbow-joint; at all events, it serves to fix or steady this 
articulation. The Extensor carpi radialis brevior assists the Extensor carpi 
radialis longior in extending the wrist, and may also act slightly as an abductor of 
the hand. The Extensor carpi ulnaris helps to extend the hand, but when acting 
alone inclines it toward the ulnar side; by its continued action it extends the 
elbow-joint. The Extensor communis digitorum extends the phalanges, then the 
wrist, and finally the elbow. It acts principally on the proximal phalanges, the 
middle and terminal phalanges being extended by the Interossei and Lumbri- 
cales. It has also a tendency to separate the fingers as it extends them. The 
Extensor minimi digiti extends similarly the little finger, and by its continued 
action it assists in extending the wrist. It is owing to this muscle that the little 
finger can be extended or pointed whilst the others are flexed. The chief action of 
the Extensor ossis metacarpi pollicis is to carry the thumb outward and backward 
from the palm of the hand, and hence it has been called the abductor pollicis longus. 
By its continued action it helps to extend and abduct the wrist. The Extensor 
brevis pollicis extends the proximal phalanx of the thumb. By its continued 
action it helps to extend and abduct the wrist. The Extensor longus pollicis 
extends the terminal phalanx of the thumb. By its continued action it helps to 
extend and abduct the wrist. The Extensor indicis extends the index finger, and OF THE HAND 
491 
by its continued action assists in extending the wrist. It is owing to this muscle 
that the index finger can be extended or pointed while the others are flexed. 
Surgical Anatomy.-The tendons of the extensor muscles of the thumb are liable to become 
strained and their sheaths inflamed after excessive exercise, producing a sausage-shaped swell- 
ing along the course of the tendon, and giving a peculiar creaking sensation to the finger when 
the muscle acts. In consequence of its often being caused by such movements as wringing 
clothes, it is known as washerwoman's sprain. In piano-players the slips which join the ten- 
dons of the Extensor communis digitorum may limit freedom of motion in individual fingers. 
" When the middle finger and little finger of the hand are brought down by the flexor muscles, 
and their balls are held down firmly against the keys of a musical instrument, as in perform- 
ing on a piano for the purpose of producing continuous sounds, and when at the same time 
it is necessary to extend and then to flex the ring-finger in order to produce accompanying 
sounds, it will be found that in the still-flexed position of the middle and little fingers, the 
ring finger can be but very slightly extended. Its complete extension, without operative inter- 
ference, can only be brought about by long-continued exertion in practice, when elongation 
of certain accessory, but restricting, tendons is made by nutritive growth."1 If there is much 
limitation division of the hindering slips is proper. This was suggested by Prof. William S. 
Forbes in 1857. 
IV. MUSCLES AND FASCIJE OF THE HAND 
The muscles of the hand are subdivided into three groups: 1. Those of the 
thumb, which occupy the radial side and produce the thenar eminence. 2. Those 
of the little finger, which occupy the ulnar side and give rise to the hypothenar 
eminence. 3. Those in the middle of the palm and within the interosseous spaces. 
Dissection (Fig. 312).-Make a transverse incision across the front of the wrist, and a 
second across the heads of the metacarpal bones: connect the two by a vertical incision in the 
middle line, and continue it through the centre of the middle finger. The anterior and poste- 
rior annular ligaments and the palmar fascia should then be dissected. 
ANTERIOR 
ANNULAR 
LIGAMENT, 
FLEXOR LONGUS POLLICIS. 
FLEXOR CARPI RADIALIS. 
Median nerve. 
IJlnar vessels. 
MUSCLES OF THUMB^ 
/PALMARIS BREVIS. 
MUSCLES OF 
LITTLE 
FINGER. 
1st Metacarpal. 
EXT. PRIM 
INTERNOD.' 
POLL. 
EXT. SEC. 
INTERNOD/ 
POLL. 
EXT. CARPI 
ULNARIS. 
Trapezium' 
Radial vessels. 
EXTENSOR 
MINIMI 
DIGITI. 
EXT. CARP. RAD. LONG. 
Trapezoid. 
EXTENSOR 
'COMMUNIS 
DIGITORUM. 
EXTENSOR CARPI RADIALIS 
BREVIOR. 
EXTENSOR INDICIS. 
Os magnum. 
Fig. 325.-Transverse section through the carpus, showing the relative positions of the tendons, vessels, 
and nerves. (Henle.) 
The Ligamentum Carpi Volare is a thickening of the deep fascia of the forearm 
(fascia antibrachii) by deep fibres just above the wrist (Fig. 330). It covers the 
flexor muscles and joins the anterior annular ligament. 
The Anterior Annular Ligament (ligamentum carpi transversum) (Fig. 325) is a 
strong, fibrous band which arches over the carpus, converting the deep groove 
on the front of the carpal bones into a canal, beneath which pass the flexor 
tendons of the fingers. It is attached, internally, to the pisiform bone and 
1 Prof. William S. Forbes in the Philadelphia Medical Journal, January 15, 1898. 492 
THE MUSCLES AND FASCIA 
the hook of the unciform bone (eminentia carpi ulnaris), and externally to the 
tuberosity of the scaphoid and to the inner part of the anterior surface and 
the ridge of the trapezium (eminentia carpi radialis). It is continuous, above, 
with the deep fascia of the forearm, of which it may be regarded as a thickened 
portion, and, below, with the palmar fascia. It is crossed by the ulnar vessels and 
nerve and the cutaneous branches of the median and ulnar nerves. At its outer 
extremity is the tendon of the Flexor carpi radialis, which lies in the groove on the 
trapezium between the attachments of 
the annular ligaments to the bone. It 
has inserted into its anterior surface a 
part of the tendon of the Palmaris longus 
and part of the tendon of the Flexor 
carpi ulnaris, and has arising from it, 
below, the small muscles of the thumb 
and little finger. Beneath it pass the 
tendons of the Flexor sublimis and Pro- 
fundus digitorum, the Flexor longus 
pollicis, and the median nerve. 
The Synovial Membranes of the Flexor 
Tendons at the Wrist.-There are two 
vaginal synovial membranes which en- 
close all the tendons as they pass be- 
neath this ligament-one for the Flexor 
sublimis and Profundus digitorum, the 
other for the Flexor longus pollicis. 
They extend up into the forearm for 
about an inch above the annular liga- 
ment, and downward about half-way 
along the metacarpal bone, where they 
terminate in a blind diverticulum around 
each pair of tendons, with the exception 
of that of the thumb and those of the 
little finger-in each of these two digits the diverticulum is continued on, and 
communicates with the synovial sheath of the tendons in the fingers. In the other 
three fingers the synovial sheath of the tendons begins as a blind pouch without 
communication with the large synovial sac (Fig- 326). 
Fig. 326.-Diagram showing the arrangement of the 
synovial sheaths of the palm and fingers. 
Surgical Anatomy.-This arrangement of the synovial sheaths explains the fact that thecal 
abscess in the thumb and little finger is liable to be followed by abscesses in the forearm, from 
extension of the inflammation along the continuous synovial sheaths. Tuberculous inflamma- 
tion is apt to occur in this situation, constituting compound palmar ganglion; it presents an hour- 
glass outline, with a swelling in front of the wrist and in the palm of the hand, and a constriction 
corresponding to the annular ligament between the two. The fluid can be forced from the one 
swelling to the other under the ligament. 
Bursae about the Hand and Wrist.-Bursae usually exist between the distal 
extremities of the metacarpal bones (bursa; intermefacarpophalangea), and a sub- 
cutaneous bursa often exists over the dorsal surface of the head of the fifth 
metacarpal bone. Subcutaneous digital dorsal bursae occur " almost constantly 
in the first finger-joints (between the first and second phalanx), occasionally in 
the second joint of the second and fourth fingers"1 (bursa' subcutaneos digitorum 
dorsales). A bursa exists between the tendon of the Extensor carpi radialis 
brevior and the base of the third metacarpal bone; another between the Flexor 
carpi ulnaris and the pisiform bone; another between the Flexor carpi radialis 
and the base of the second metacarpal bone. 
1 Hand Atlas of Human Anatomy. By Werner Spalteholz. Translated and edited by Lewellys F. Barker. OF THE HAND 
493 
Lhe Posterior Annular Ligament (Itg amentum carpi dorsale) is a strong fibrous 
band extending obliquely downward and inward across the back of the wrist, and 
consisting of the deep fascia of the back of the forearm, strengthened by the 
addition of some transverse fibres. It binds down the extensor tendons in their 
passage to the fingers, being attached, internally, to the styloid process of the ulna, 
the cuneiform and pisiform bones; externally, to the margin of the radius; and, in 
its passage across the wrist, to the elevated ridges on the posterior surface of the 
radius. It presents six compartments for the passage of tendons, each of which is 
lined by a separate synovial membrane 
(Fig. 327). These are, from without 
inward: 1. On the outer side of the 
styloid process, for the tendons of the 
Extensor ossis metacarpi and Extensor 
brevis pollicis. 2. Behind the styloid 
process, for the tendons of the Ex- 
tensor carpi radialis longior and bre- 
vior. 3. About the middle of the 
posterior surface of the radius, for the 
tendon of the Extensor longus pollicis. 
4. To the inner side of the latter, for 
the tendons of the Extensor communis 
digitorum and Extensor indicis. 5. 
Opposite the interval between the 
radius and ulna, for the Extensor minimi digiti. 6. Grooving the back of the 
ulna, for the tendon of the Extensor carpi ulnaris. The synovial membranes 
lining these sheaths are usually very extensive, reaching from above the annular 
ligament down upon the tendons for a variable distance on the back of the 
hand. 
The Deep Palmar Fascia (aponeurosis palmar is).-The deep palmar fascia 
(Fig. 328) forms a common sheath which invests the muscles of the hand. 
It consists of a central and two lateral portions. 
The Central Portion occupies the middle of the palm, is triangular in shape, of 
great strength and thickness, and binds down the tendons and protects the vessels 
and nerves in this situation. It is narrow above, where it is attached to the lower 
margin of the annular ligament, and receives the expanded tendon of the Pal- 
maris longus muscle. Below, it is broad and expanded, and divides into four 
slips for the four fingers. Each slip gives off superficial fibres, which are inserted 
into the skin of the palm and finger, those to the palm joining the skin at the 
furrow corresponding to the metacarpo-phalangeal articulation, and those to the 
fingers passing into the skin at the transverse fold at the base of the fingers. The 
deeper part of each slip subdivides into two processes, which are inserted into the 
lateral margins of the anterior (glenoid.)'ligament of the metacarpo-phalangeal 
joint. From the sides of these processes offsets are sent backward, to be attached 
to the borders of the lateral surfaces of the metacarpal bones at their distal extrem- 
ities. By this arrangement short channels are formed on the front of the lower 
ends of the metacarpal bones, through which the flexor tendons pass. Dr. W. W. 
Keen describes a fifth slip as frequently found passing to the thumb. The inter- 
vals left in the fascia between the four fibrous slips transmit the digital vessels 
and nerves and the tendons of the Lumbricales. At the points of division of the 
palmar fascia into the slips above mentioned numerous strong, transverse fibres 
bind the separate processes together. The palmar fascia is intimately adherent 
to the integument bv dense fibro-areolar tissue, forming the superficial palmar 
fascia, and gives origin by its inner margin to the Palmaris brevis: it covers the 
superficial palmar arch, the tendons of the flexor muscles, and the branches of 
Fig. 327.-Transverse section through the wrist, show- 
ing the annular ligaments and the canals for the passage 
of the tendons. 494 
THE MUSCLES AND FASCIAE 
the median and ulnar nerves, and on each side it gives off a vertical septum, which 
is continuous with the interosseous aponeurosis and separates the lateral from 
the middle palmar group of muscles. 
The Lateral Portions of the Palmar Fascia are thin, fibrous layers, which cover, 
on the radial side, the muscles of the ball of the thumb, and, on the ulnar side, the 
muscles of the little finger; they are continuous with the dorsal fascia, and in the 
palm with the central portion of the palmar fascia. 
Digital artery. 
Digital nerves.' 
Fig. 328.-Palmar fascia. (From a preparation in the Museum of the Royal College of Surgeons of England.) 
4 
The Superficial Transverse Ligament of the Fingers is a thin, fibrous band which 
stretches across the roots of the four fingers, and is closely attached to the skin 
of the clefts, and internally to the fifth metacarpal bone, forming a sort of rudi- 
mentary web. Beneath it the digital vessels and nerves pass onward to their 
destination. 
Surgical Anatomy.-The palmar fascia is liable to undergo contraction, producing a very 
inconvenient deformity known as Dupuytren's contraction. The ring and little fingers are most 
frequently implicated, but the middle, index, and the thumb may be involved. The proximal 
phalanx is drawn down and cannot be straightened, and the two distal phalanges become simi- 
larly flexed as the disease advances. THE RADIAL REGION 
495 
11. The Radial Region (Figs. 329, 330). 
Abductor pollicis. 
Opponens pollicis. 
Flexor brevis pollicis. 
Adductor obliquus pollicis. 
Adductor transversus pollicis. 
The Abductor Pollicis (m. abductor pollicis brevis) (Fig. 330) is a thin, flat 
muscle, placed immediately beneath the integument. It arises from the anterior 
annular ligament, the tuberosity of the scaphoid, and the ridge of the trapezium, 
Fig. 329.-Adductor pollicis, Opponens pollicis, and Pronator quadrat us. (Testut.) 
frequently by two distinct slips; and, passing outward and downward, is inserted 
by a thin, flat tendon into the radial side of the base of the first phalanx of the 
thumb, sending a slip to join the tendon of the Extensor longus pollicis. 496 
THE MUSCLES AND FASCIAE 
Relations.-By its superficial surface, with the palmar fascia and superficialis 
volae artery, which frequently perforates it. By its deep surface, with the Opponens 
pollicis, from which it is separated by a thin aponeurosis. Its inner border is 
separated from the Flexor brevis pollicis by a narrow cellular interval. 
Fig. 330.-Muscles of the left hand. Palmar surface. 
The Opponens Pollicis (Figs. 329 and 330), often called the flexor ossis meta- 
carpi pollicis, is a small, triangular muscle, placed beneath the preceding. It arises 
from the palmar surface of the ridge on the trapezium and from the annular 
ligament, passes downward and outward, and is inserted into the whole length of 
the metacarpal bone of the thumb on its radial side. THE RADIAL REGION 
497 
Relations.-By its superflcial surface, with the Abductor and Flexor brevis 
pollicis. By its deep surface, with the trapezio-metacarpal articulation. By its 
inner border, with the Adductor obliquus pollicis. 
The Flexor Brevis Pollicis (m. flexor pollicis brevis) (Fig. 330) consists of two 
portions, outer and inner. The outer and more superficial portion arises from the 
outer two-thirds of the lower border of the anterior annular ligament, and passes 
along the outer side of the tendon of the Flexor longus pollicis; and, becoming 
tendinous, has a sesamoid bone developed in its tendon, and is inserted into the 
outer side of the base of the first phalanx of the thumb. The inner and deeper 
portion of the muscle is very small, and arises from the ulnar side of the first 
metacarpal bone beneath the Adductor obliquus pollicis, and is inserted into the 
inner side of the base of the first phalanx with this muscle. 
Relations.-By its superficial surface, with the palmar fascia. By its deep sur- 
face, with the tendon of the Flexor longus pollicis. By its external surface, with 
the Opponens pollicis. Behind, with the Adductor obliquus pollicis. 
The Adductor Obliquus Pollicis (m. adductor pollicis) (Figs. 329 and 330) 
arises by several slips from the os magnum, the bases of the second and third 
metacarpal bones, the anterior carpal ligaments, and the sheath of the tendon 
of the Flexor carpi radialis. From this origin the greater number of fibres 
pass obliquely downward and converge to a tendon, which, uniting with the 
tendons of the deeper portion of the Flexor brevis pollicis and the Adductor 
transversus, is inserted into the inner side of the base of the first phalanx of the 
thumb, a sesamoid bone being developed in the tendon of insertion. A consid- 
erable fasciculus, however, passes more obliquely outward beneath the tendon 
of the long flexor to join the superficial portion of the short flexor and the 
Abductor pollicis.1 
Relations.-By its superficial surface, with the Flexor longus pollicis and the 
outer head of the Flexor brevis pollicis. Its deep surface is in relation with the 
deep palmar arch, which passes between the two adductors. 
The Adductor Transversus Pollicis (Figs. 329 and 330) is the most deeply 
seated of this group of muscles. It is of a triangular form, arising, by its broad 
base, from the lower two-thirds of the metacarpal bone of the middle finger on 
its palmar surface; the fibres, proceeding outward, converge to be inserted, with 
the inner part of the Flexor brevis pollicis, and the Adductor obliquus pollicis, 
into the ulnar side of the base of the first phalanx of the thumb. From the 
common tendon of insertion a slip is prolonged to the Extensor longus pollicis. 
'rhe name adductor pollicis is frequently used to mean both of the adductors 
(Figs. 329 and 330). 
Relations.-By its superficial surface, with the Adductor obliquus pollicis, the 
tendons of the Flexor profundus, and the Lumbricales. Its deep surface covers 
the first two interosseous spaces, from which it is separated by a strong aponeu- 
rosis. 
Three of these muscles of the thumb, the Abductor, the Adductor transversus, 
and the Flexor brevis pollicis, at their insertions give off fibrous expansions which 
join the tendon of the Extensor longus pollicis. This permits of flexion of the 
proximal phalanx and extension of the terminal phalanx at the same time. These 
expansions, originally figured by Albinus, have been more recently described by 
M. Duchenne.2 
Nerves.-The Abductor, Opponens, and outer head of the Flexor brevis pollicis 
are supplied by the sixth cervical through the median nerve; the inner head of the 
Flexor brevis, and the Adductors, by the eighth cervical through the ulnar nerve. 
1 This muscle is described by some as the deep portion of the Flexor brevis pollicis. 
2 Physiologic des Mouvements. 498 
THE MUSCLES AND FASCIAE 
Actions.-The actions of the muscles of the thumb are almost sufficiently indi- 
cated by their names. This segment of the hand is provided with three extensors 
-an extensor of the metacarpal bone, an extensor of the first, and an extensor of 
the second phalanx; these occupy the dorsal surface of the forearm and hand. 
There are also three flexors on the palmar surface-a flexor of the metacarpal 
bone, a flexor of the proximal, and a flexor of the terminal phalanx; there is also 
an Abductor and two Adductors. The Abductor pollicis moves the metacarpal 
bone of the thumb outward; that is, away from the index finger. The Flexor 
ossis metacarpi pollicis flexes the metacarpal bone-that is, draws it inward over 
the palm-and at the same time rotates the bone, so as to turn the ball of the 
thumb toward the fingers, thus producing the movement of opposition. The 
Flexor brevis pollicis flexes and adducts the proximal phalanx of the thumb. The 
Adductores pollicis move the metacarpal bone of the thumb inward; that is, 
toward the index finger. These muscles give to the thumb its extensive range of 
motion. It will be noticed, however, that in consequence of the position of the 
first metacarpal bone, these movements differ from the corresponding movements 
of the metacarpal bones of the other fingers. Thus extension of the thumb more 
nearly corresponds to the motion of abduction in the other fingers, and flexion to 
adduction. 
12. The Ulnar Region (Fig. 330) 
Palmaris brevis. 
Abductor minimi digiti. 
Flexor brevis minimi digiti. 
Opponens minimi digiti. 
The Palmaris Brevis is a thin quadrilateral muscle placed beneath the integu- 
ment on the ulnar side of the hand. It arises by tendinous fasciculi from the 
anterior annular ligament and palmar fascia; the fleshy fibres pass inward, to be 
inserted into the skin on the inner border of the palm of the hand. 
Relations.-By its superficial surface, with the integument, to which it is inti- 
mately adherent, especially by its inner extremity; by its deep surface, with the 
inner portion of the palmar fascia, which separates it from the ulnar vessels and 
nerve, and from the muscles of the ulnar side of the hand. 
The Abductor Minimi Digiti (m. abductor digiti quinti) is situated on the ulnar 
border of the palm of the hand. It arises from the pisiform bone and from the 
tendon of the Flexor carpi ulnaris, and terminates in a flat tendon, which divides 
into two slips; one is inserted into the ulnar side of the base of the first phalanx 
of the little finger. The other slip is inserted into the ulnar border of the aponeu- 
rosis of the Extensor minimi digiti. 
Relations.-By its superficial surface, with the inner portion of the palmar fascia 
and the Palmaris brevis; by its deep surface, with the Opponens minimi digiti; 
by its outer border, with the Flexor brevis minimi digiti. 
The Flexor Brevis Minimi Digiti (m. flexor digiti quinti brevis) lies on the same 
plane as the preceding muscle, on its radial side. It arises from the convex aspect 
of the hook of the unciform bone and anterior surface of the annular ligament, 
and is inserted into the inner side of the base of the first phalanx of the little finger. 
It is separated from the Abductor at its origin by the deep branches of the ulnar 
artery and nerve. This muscle is sometimes wanting; the Abductor is then, 
usually, of large size. 
Relations.-By its superficial surface, with the internal portion of the palmar 
fascia and the Palmaris brevis; by its deep surface, with the Opponens. The deep 
branch of the ulnar artery and the corresponding branch of the ulnar nerve pass 
between the Abductor and Flexor brevis minimi digiti muscles. 
The Opponens Minimi Digiti (m. opponens digiti quinti).-This muscle is 
sometimes called the flexor ossis metacarpi (Fig. 320), is of a triangular form, and 
placed immediately beneath the preceding muscles. It arises from the convexity THE MIDDLE PALMAR REGION 
499 
of the hook of the unciform bone and the contiguous portion of the anterior 
annular ligament; its fibres pass downward and inward, to be inserted into the 
whole length of the metacarpal bone of the little finger, along its ulnar margin. 
Relations.-By its superficial surface, with the Flexor brevis and Abductor 
minimi digiti; by its deep surface, with the Interossei muscles in the fourth meta- 
carpal space, the metacarpal bone, and the Flexor tendons of the little finger. 
Nerves.-All the muscles of this group are supplied by the eighth cervical nerve 
through the ulnar nerve. 
Actions.-The Abductor minimi digiti abducts the little finger from the middle 
line of the hand. It corresponds to a dorsal interosseous muscle. It also assists 
in flexing the proximal phalanx and extending the second and third phalanges. 
The Flexor brevis minimi digiti abducts the little finger from the middle line of 
the hand. It also assists in flexing the proximal phalanx. The Opponens minimi 
digiti draws forward the fifth metacarpal bone, so as to deepen the hollow of the 
palm. The Palmaris brevis corrugates the skin on the inner side of the palm of 
the hand and probably serves to protect the ulnar nerve and artery from damage 
by the pressure of grasping a hard object. 
Lumbricales. 
13. The Middle Palmar Region 
Interossei dorsales. 
Interossei palmares 
The Lumbricales (Fig. 330) are four small fleshy fasciculi, accessories to the 
deep Flexor muscle. They arise from the tendons of the deep Flexor: the first and 
second, from the radial side and palmar surface of the tendons of the index and 
middle fingers respectively; the third, from the contiguous sides of the tendons of 
the middle and ring fingers; and the fourth, from the contiguous sides of the 
tendons of the ring and little fingers. They pass to the radial side of the corre- 
sponding fingers and opposite the metacarpo-phalangeal articulation each tendon 
is inserted into the tendinous expansion of the Extensor communis digitorum, 
covering the dorsal aspect of each finger. 
The Interossei Muscles (Figs. 331 and 332) are so named from occupying 
the intervals between the metacarpal bones, and are divided into two sets, dorsal 
and palmar. 
The Dorsal interossei (mm. interossei dor sales') are four in number, larger than the 
palmar, and occupy the intervals between the metacarpal bones. They are bipen- 
niform muscles, arising by two heads from the adjacent sides of the metacarpal 
bones, but more extensively from the metacarpal bone of the finger into which the 
muscle is inserted. They are inserted into the bases of the first phalanges and into 
the aponeurosis of the common Extensor tendon. Between the double origin of 
each of these muscles is a narrow triangular interval, through the first of which 
passes the radial artery; through each of the other three passes a perforating 
branch from the deep palmar arch. 
The First dorsal interosseous muscle or Abductor indicis is larger than the 
others. It is flat, triangular in form, and arises by two heads, separated by a 
fibrous arch, for the passage of the radial artery from the dorsum to the palm of 
the hand. The outer head arises from the upper half of the ulnar border of the 
first metacarpal bone; the inner head, from almost the entire length of the radial 
border of the second metacarpal bone; the tendon is inserted into the radial side 
of the index finger. The second and third dorsal interossei are inserted into the 
middle finger, the former into its radial, the latter into its ulnar side. The fourth 
is inserted into the ulnar side of the ring finger. 
The Palmar interossei (mm. interossei volares), three in number, are smaller than 
the Dorsal, and placed upon the palmar surface of the metacarpal bones, rather 500 
THE MUSCLES AND EASCHE 
than between them. Each muscle arises from the entire length of the meta- 
carpal bone of one finger, and is inserted into the side of the base of the first 
phalanx and aponeurotic expansion of the common extensor tendon of the same 
finger. The first arises from the ulnar side of the second metacarpal bone, and 
is inserted into the same side of the first phalanx of the index finger. The second 
arises from the radial side of the fourth metacarpal bone, and is inserted into the 
Fig. 331.-The Dorsal interossei of left hand. 
Fig. 332.-The Palmar interossei of left hand. 
same side of the ring finger. The third arises from the radial side of the fifth 
metacarpal bone, and is inserted into the same side of the little finger. From 
this account it may be seen that each finger is provided with two Interosseous 
muscles, with the exception of the little finger, in which the Abductor muscle 
takes the place of one of the pair. 
Nerves.-The two outer Lumbricales are supplied by the sixth cervical nerve, 
through the third and fourth digital branches of the median nerve: the two inner 
Lumbricales and all the Interossei are supplied by the eighth cervical nerve, 
through the deep palmar branch of the ulnar nerve. Brooks states that the third 
lumbrical received a twig from the median in twelve out of twenty-one cases. 
Actions.-The Palmar interossei muscles adduct the fingers to an imaginary 
line drawn longitudinally through the centre of the middle finger; and the Dorsal 
interossei abduct the fingers from that line. In addition to this, the Interossei, in 
conjunction with the Lumbricales, flex the first phalanges at the metacarpo-phalan- 
geal joints, and extend the second and third phalanges in consequence of their 
insertion into the expansion of the extensor tendons. The Extensor communis 
digitorum is believed to act almost entirely on the first phalanges. 
SURFACE FORM OF THE UPPER EXTREMITY. 
The Pectoralis major muscle largely influences surface form and conceals a considerable part 
of the thoracic wall in front. Its sternal origin presents a festooned border which bounds and 
determines the width of the sternal furrow. Its clavicular origin is somewhat depressed and flat- 
tened, and between the two portions of the muscle is often an oblique depression which differen- 
tiates the one from the other. The outer margin of the muscle is generally well marked above, 
and bounds the infraclavicular fossa, a triangular interval which separates the Pectoralis major SURFACE FORM OF THE UPPER EXTREMITY 
501 
from the Deltoid. It gradually becomes less marked as it approaches the tendon of insertion, 
and becomes more closely blended with the Deltoid muscle. The lower border of the Pectoralis 
major forms the rounded anterior axillary fold, and corresponds with the direction of the fifth rib. 
The Pectoralis minor muscle influences surface form. When the arm is raised its lowest slip 
of origin produces a local fulness just below the border of the anterior fold of the axilla, and so 
serves to break the sharp line of the lower border of the Pectoralis major muscle, which is pro- 
duced when the arm is in this position. The origin of the Serratus magnus muscle produces a 
very characteristic surface marking. When the arm is raised from the side in a well-developed 
subject, the five or six lower serrations are plainly discernible, forming a zigzag line, caused by 
the series of digitations, which diminish in size from above downward, and have their apices 
arranged in the form of a curve. When the arm is lying by the side, the first serration to 
appear, at the lower margin of the Pectoralis major, is the one attached to the fifth rib. The 
Deltoid muscle, with the prominence of the upper extremity of the humerus, produces the 
rounded outline of the shoulder. It is rounder and fuller in front than behind, where it presents 
a somewhat flattened form. Its anterior border, above, presents a rounded, slightly curved 
eminence, which bounds externally the infraclavicular fossa; below, it is closely united with the 
Pectoralis major. Its posterior border is thin, flattened, and scarcely marked above; below, it 
is thicker and more prominent. When the muscle is in action, the middle portion becomes 
irregular, presenting alternate longitudinal elevations and depressions, the elevations correspond- 
ing to the fleshy portions, the depressions to the tendinous intersections of the muscle. The 
insertion of the Deltoid is marked by a depression on the outer side of the middle of the arm. 
Of the scapular muscles, the only one which materially influences surface form is the Teres 
major, which assists the Latissimus dorsi in forming the thick, rounded fold of the posterior 
boundary of the axilla. When the arm is raised, the Coraco-brachialis reveals itself as a long, 
narrow elevation which emerges from under cover of the anterior fold of the axilla and runs 
downward, internal to the shaft of the humerus. When the arm is hanging by the side, its 
front and inner part presents the prominence of the Biceps, bounded on either side by an inter- 
muscular depression. This muscle determines the contour of the front of the arm, and extends 
from the anterior margin of the axilla to the bend of the elbow. Its upper tendons are con- 
cealed by the Pectoralis major and the Deltoid, and its lower tendon sinks into the space at the 
bend of the elbow. When the muscle is in a state of complete contraction-that is to say, 
when the forearm has been flexed and supinated-it presents a rounded convex form, bulged 
out laterally, and its length is diminished. On each side of the Biceps, at the lower part of 
the arm, the Brachialis anticus is discernible. On the outer side it forms a narrow eminence 
which extends some distance up the arm along the border of the Biceps. On the inner side it 
shows itself only as a little fulness just above the elbow. On the back of the arm the long head 
of the Triceps may be seen as a longitudinal eminence emerging from under cover of the Deltoid, 
and gradually merging into the longitudinal flattened plane of the tendon of the muscle on the 
lower part of the back of the arm. The tendon of insertion of the muscle extends about half- 
way up the back of the arm, where it forms an elongated flattened plane when the muscle is in 
action. Under similar conditions the surface forms produced by the three heads of the muscle 
are well seen. On the anterior aspect of the elbow are to be seen two muscular elevations, 
one on each side, separated above and converging below so as to form a triangular space. 
Of these, the inner elevation, consisting of the flexors and pronator, forms the prominence 
along the inner side and front of the forearm. It is a fusiform mass, pointed above at the 
internal condyle and gradually tapering off below. The Pronator radii teres, the innermost 
muscle of the group, forms the boundary of the triangular space at the bend of the elbow. It 
is shorter, less prominent, and more oblique than the outer boundary. The most prominent 
part of the eminence is produced by the Flexor carpi radialis, the muscle next in order on the 
inner side of the preceding one. It forms a rounded prominence above, and can be traced 
downward to its tendon, which can be felt lying on the front of the wrist, nearer to the radial 
than to the ulnar border, and to the inner side of the radial artery. The Palmaris longus pre- 
sents no surface marking above, but below is the most prominent tendon on the front of the 
wrist, standing out, when the muscle is in action, as a sharp, tense cord beneath the skin. The 
Flexor sublimis digitomm does not directly influence surface form. The position of its four 
tendons on the front of the lower part of the forearm is indicated by an elongated depression 
between the tendons of the Palmaris longus and the Flexor carpi ulnaris. The Flexor carpi 
ulnaris occupies a small part of the posterior surface of the forearm, and is separated from the 
extensor and supinator group, which occupies the greater part of this surface, by the ulnar 
furrow, produced by the subcutaneous posterior border of the ulna. Its tendon can be perceived 
along the ulnar border of the front of the forearm, and is most marked when the hand is flexed 
and adducted. The deep muscles of the front of the forearm have no direct influence on sur- 
face form. The external group of muscles of the forearm, consisting of the extensors and supi- 
nators, occupy the outer and a considerable portion of the posterior surface of this region. It 
has a fusiform outline, which is altogether on a higher level than the pronato-flexor group. Its 
apex emerges from between the Triceps and Brachialis anticus muscles some distance above the 502 
THE MUSCLES AND FASCIAE 
elbow-joint, and acquires its greatest breadth opposite the external condyle, and thence gradually 
shades off into a flattened surface. About the middle of the forearm it divides into two 
longitudinal eminences which diverge from each other, leaving a triangular interval between 
them. The outer of these two groups of muscles consists of the Supinator longus and the 
Extensor carpi radialis longior et brevior, which form a longitudinal eminence descending from 
the external condylar ridge in the direction pf the styloid process of the radius. The other and 
more posterior group consists of the Extensor communis digitorum, the Extensor minimi digiti, 
and the Extensor carpi ulnaris. It commences above as a tapering form at the external con- 
dyle of the humerus, and is separated behind at its upper part from the Anconeus by a well- 
marked furrow, and below, from the pronato-flexor mass, by the ulnar furrow. In the triangular 
interval left between these two groups the extensors of the thumb and index finger are seen. 
The only two muscles of this region which require special mention as independently influencing 
surface form are the Supinator longus and the Anconeus. The inner border of the Supinator 
longus forms the outer boundary of the triangular space at the bend of the elbow. It com- 
mences as a rounded border above the condyle, and is longer, less oblique, and more prominent 
than the inner boundary. Lower down, the muscle forms a full fleshy mass on the outer side of 
the upper part of the forearm, and below tapers into a tendon, which may be traced down to 
the styloid process of the radius. The Anconeus presents a well-marked and characteristic 
surface form in the shape of a triangular, slightly elevated surface, immediately external to the 
subcutaneous posterior surface of the olecranon, and differentiated from the common extensor 
group by a well-marked oblique longitudinal depression. The upper angle of the triangle corre- 
sponds to the external condyle, and is marked by a depression or dimple in this situation. In 
the interval caused by the divergence from each other of the two groups of muscles into which 
the extensor and supinator group is divided at the lower part of the forearm an oblique elongated 
eminence is seen, caused by the emergence of two of the extensors of the thumb from their 
deep origin at the back of the forearm. This eminence, full above and becoming flattened 
out and partially subdivided below, runs downward and outward over the back and outer sur- 
face of the radius to the outer side of the wrist-joint, where it forms a ridge, especially marked 
when the thumb is extended, which passes onward to the posterior aspect of the thumb. The 
tendons of most of the extensor muscles are to be seen and felt at the level of the wrist-joint. 
Most externally are the tendons of the Extensor ossis metacarpi pollicis and the Extensor brevis 
pollicis, forming a vertical ridge over the outer side of the joint from the styloid process of the 
radius to the thumb. Internal to this is the oblique ridge produced by the tendon of the Exten- 
sor longus pollicis, very noticeable when the muscle is in action. The Extensor carpi radialis 
longior is scarcely to be felt, but the Extensor carpi radialis brevior can be distinctly perceived 
as a vertical ridge emerging from under the inner border of the tendon of the Extensor longus 
pollicis, when the hand is forcibly extended at the wrist. Internal to this, again, can be felt 
the tendons of the Extensor indicis, Extensor communis digitorum, and Extensor minimi digiti; 
the latter tendon being separated from those of the common extensor by a slight furrow. The 
muscles of the hand are principally concerned, as far as regards surface-form, in producing 
the thenar and hypothenar eminences, and individually are not to be distinguished, on the sur- 
face, from each other. The Adductor transversus pollicis is, however, an exception to this; 
its anterior border gives rise to a ridge across the web of skin connecting the thumb to the rest 
of the hand. The thenar eminence is much larger and rounder than the hypothenar one, which 
i>resents a longer and narrower eminence along the ulnar side of the hand. When the Palmaris 
>revis is in action it produces a wrinkling of the skin over the hypothenar eminence, and a deep 
dimple on the ulnar border of the hand. The anterior extremities of the Lumbrical muscles 
help to produce the soft eminences just behind the clefts of the fingers, separated from each 
other by depressions corresponding to the flexor tendons in their sheaths. Between the thenar 
and hypothenar eminences, at the wrist-joint, is a slight groove or depression, widening out as 
it approaches the fingers; beneath this we have the strong central part of the palmar fascia. 
Here we have some furrows, which are pretty constant in their arrangement, and bear some 
resemblance to the letter M. One of these furrows passes obliquely outward from the groove 
between the thenar and hypothenar regions near the wrist to the head of the metacarpal bone 
of the index finger. A second passes inward, with a slight inclination upward, from the ter- 
mination of the first to the ulnar side of the hand. A third runs nearly parallel with the second 
and about three-quarters of an inch below it. Lastly, crossing these two latter furrows, is an 
oblique furrow parallel with the first. The skin of the palm of the hand differs considerably 
from that of the forearm. At the wrist it suddenly becomes hard and dense, and covered with 
a thick layer of cuticle. The skin in the thenar region presents these characteristics less than 
elsewhere. In spite of this hardness and density, the skin of the palm is exceedingly sensitive 
and very vascular. It is destitute of hair, and no sebaceous follicles have been found in this 
region. Over the fingers the skin again becomes thinner, especially at the flexures of the joints, 
and over the terminal phalanges it is thrown into numerous ridges in consequence of the arrange- 
ment of the papillae in it. These ridges form, in different individuals, distinctive and permanent 
patterns, which may be used for purposes of identification. The superficial fascia in the palm SURGICAL ANATOMY OF THE UPPER EXTREMITY 
503 
is made up of dense fibro-fatty tissue. This tissue binds down the skin so firmly to the deep 
palmar fascia that very little movement is permitted between the two. On the back of the hand 
the Dorsal interossei produce elongated swellings between the metacarpal bones. The first 
dorsal interosseous (Abductor indicis), when the thumb is closely adducted to the hand, forms 
a prominent fusiform bulging; the other interossei are not so marked. 
SURGICAL ANATOMY OF THE UPPER EXTREMITY. 
I he student, having completed the dissection of the muscles of the upper extremity, should 
consider the effects likely to be produced by the action of the various muscles in fracture of the 
bones. 
In considering the actions of the various muscles upon fractures of the upper extremity, the 
most common forms of injury have been selected both for illustration and description. 
Fracture of the middle of the clavicle (Fig. 333) is always attended with considerable dis- 
placement; the inner end of the outer fragment is displaced inward and backward, while the 
outer end of the same fragment is rotated forward. The whole outer fragment is somewhat 
depressed. The deformity is described by saying that the shoulder goes downward, forward, 
and inward. 
The displacement is produced as follows: inward, by the muscles passing from the chest to 
the outer fragment of the clavicle, to the scapula, and to the humerus-viz., the Subclavius and 
the Pectoralis minor, and, to a less extent, the Pectoralis major and the Latissimus dorsi; back- 
ward, in consequence of the rotation of the outer fragment. The Serratus magnus causes the 
scapula to rotate on the wall of the chest; this carries the acromion and outer end of the outer 
fragment of the clavicle forward and causes the piece of bone to rotate round a vertical axis 
through its centre, and so carries the inner end of the outer portion backward. The depression 
of the whole outer fragment is produced by the weight 
of the arm and by the contraction of the Deltoid. The 
outer end of the inner fragment appears to be elevated, 
the skin being drawn tensely over it ; this is owing to 
the depression of the outer fragment, as the inner frag- 
ment is usually kept fixed by the costo-clavicular liga- 
ment and by the antagonism between the Sternomastoid 
and Pectoralis major muscles. But it may be raised by 
an unusually strong Sterno-mastoid, or by the inner end 
of the outer fragment getting below and behind it. The 
causes of displacement having been ascertained, it is 
easy to apply the appropriate treatment. The outer 
fragment is to be drawn outward, and, together with the 
scapula, raised upward to a level with the inner frag- 
ment, and retained in that position. The formula for 
correcting the deformity is as follows: carry the shoulder 
upward, outward, and backward. 
In fracture of the acromial end of the clavicle, between 
the conoid and trapezoid ligaments, only slight displace- 
ment occurs, as these ligaments, from their oblique in- 
sertion, serve to hold both portions of the bone in appo- 
sition. Fracture, also, of the sternal end, internal to 
the costoclavicular ligament, is attended with only slight 
displacement, this ligament serving to retain the frag- 
ments in close apposition. 
Fracture of the acromion process usually arises from 
violence applied to the upper and outer part of the 
shoulder; it is generally known by the rotundity of the 
shoulder being lost, from the Deltoid drawing the fractured portion downward and forward; 
and the displacement may easily be discovered by tracing the margin of the clavicle outward, 
when the fragment will be found resting on the front and upper part of the head of the 
humerus. In order to relax the anterior and outer fibres of the Deltoid (the opposing muscle), 
the arm should be drawn forward across the chest and the elbow well raised, so that the head 
of the bone may press the acromion process upward and retain it in its position. 
Fracture of the coracoid process is an extremely rare accident, and is usually caused by a 
sharp blow on the point of the shoulder. Displacement is here produced by the combined 
actions of the Pectoralis minor, short head of the Biceps, and Coraco-brachialis, the former 
muscle drawing the fragment inward, and the latter muscles directly downward, the amount of 
displacement being limited by the connection of this process to the acromion by means of the 
coraco-acromial ligament. In many cases there appears to have been little or no displacement, 
Fig. 333.-Fracture of the middle of the 
clavicle. 504 
THE MUSCLES AND FASCIA 
from the fact that the coraco-clavicular ligament has remained intact, and has kept the separated 
fragment from displacement. In order to relax these muscles and replace the fragments in 
close apposition, the forearm should be flexed so as to relax the Biceps, and the arm drawn 
forward and inward across the chest, so as to relax the Coraco-brachialis; the humerus should 
then be pushed upward against the coraco-acromial ligament, and the arm retained in that 
position. 
Fracture of the surgical neck of the humerus (Fig. 334) is very common, is attended with 
considerable displacement, and its appearances correspond somewhat with those of dislocation 
of the head of the humerus into the axilla. The upper fragment is slightly elevated under the 
coraco-acromial ligament by the muscles attached to the greater and lesser tuberosities; the 
lower fragment is drawn inward by the Pectoralis major, Latissimus dorsi, and Teres major; and 
the humerus is thrown obliquely outward from the side by the Deltoid, and occasionally elevated 
so as to cause the upper end of the lower fragment to project 
beneath and in front of the coracoid process. The deformity 
is reduced by fixing the shoulder, and drawing the arm out- 
ward and downward. To counteract the opposing muscles, 
and to keep the fragments in position, a conical-shaped pad 
should be placed with the apex in the axilla; while the fore- 
arm is flexed to an angle of 90 degrees the shoulder is padded 
with cotton, a shoulder-cap of plaster-of-Paris is applied to 
cover the shoulder, a portion of the chest and back, and the 
arm down to the external condyle (Scudder). The arm, with 
the elbow slightly forward, is bandaged to the side. In some 
cases a splint is placed between the axillary pad and the 
inner side of the arm. 
In fracture of the shaft of the humerus below the insertion 
of the Pectoralis major, Latissimus dorsi, and Teres major, 
and above the insertion of the Deltoid, there is also consider- 
able deformity, the upper fragment being drawn inward by 
the first-mentioned muscles, and the lower fragment upward 
and outward by the Deltoid, producing shortening of the limb 
and a considerable prominence at the seat of fracture, from 
the fractured ends of the bone riding over one another, espe- 
cially if the fracture takes place in an oblique direction. The 
fragments may be brought into apposition by extension from 
the elbow, and are retained in that position by adopting the same means as in the preceding 
injury, or by the use of an internal angular splint with three short humeral splints. 
In fractures of the shaft of the humerus immediately below the insertion of the Deltoid, the 
amount of deformity depends greatly upon the direction of the fracture. If it occurs in a trans- 
verse direction, only slight displacement takes place, the upper fragment being drawn a little 
forward; but in oblique fracture the combined actions of the Biceps and Brachialis anticus 
muscles in front and the Triceps behind draw upward the lower fragment, causing it to glide 
over the upper fragment, either backward or forward, according to the direction of the fracture. 
Simple extension reduces the deformity, and the application of an internal angular splint and 
three short humeral splints will retain the fragments in apposition. Care should be taken not 
to raise the elbow, but the forearm and hand may be supported in a sling. 
Fracture of the humerus (Fig. 335) above the condyle deserves very attentive considera- 
tion, as the general appearances correspond somewhat with those produced by separation 
of the epiphysis of the humerus, and with those of dislocation of the radius and ulna back- 
ward. if the direction of the fracture is oblique from above, downward and forward, the 
lower fragment is drawn upward by the Brachialis anticus and Biceps in front and the Triceps 
behind; and at the same time is drawn backward behind the upper fragment by the Triceps. 
This injury may be diagnosticated from dislocation by the increased mobility in fracture, the 
existence of crepitus, and the fact of the deformity being remedied by extension, on the discon- 
tinuance of which it is reproduced. The age of the patient is of importance in distinguishing 
this form of injury from separation of the epiphysis. If fracture occurs in the opposite direc- 
tion to that shown in Fig. 335, the lower fragment is drawn upward and forward, causing a 
considerable prominence in front, and the upper fragment projects backward beneath the 
tendon of the Triceps muscle. 
Fractures of the lower extremity of the humerus are spoken of as fractures in the neighbor- 
hood of the elbow-joint. The term includes fracture of the external condyle, of the internal condyle, 
at the base of the condyles, and T- or Y-shaped fracture, the two condyles being separated 
from each other and from the shaft of the humerus. Such injuries are followed by great and 
rapid swelling. Whenever possible the x-rays are used to aid in diagnosis, and the patient is 
placed under ether, to set and dress the fracture. 
In fracture of the inner condyle the fragment with the ulna passes up and back, and when 
Fig. 334.-Fracture of the surgical 
neck of the humerus. SURGICAL ANATOMY OF THE UPPER EXTREMITY 
505 
the forearm is extended the ulna projects posteriorly. The " carrying function " of the arm is 
lost, because the forearm deviates to the ulnar side. 
In all cases of fracture of the lower end of the humerus, except fracture at the base of 
the condyles, effect reduction by traction upon the forearm, and supination, extension, and 
bending the forearm slowly into acute flexion. In transverse fracture above the condyles 
draw the forearm and the lower fragment downward and forward and push the upper frag- 
ment back. A case can be treated by maintaining a position of acute flexion (Jones's position) 
or by using an anterior angular splint. Allis and others treat in extension. 
Fracture of the olecranon process (Fig. 336) is a frequent accident. The detached fragment 
is displaced upward, by the action of the Triceps muscle, from half an inch to two inches; the 
prominence of the elbow is consequently lost, and a deep hollow is felt at the back part of the 
joint, which is much increased on flexing the limb. The patient at the same time loses, more 
or less, the power of extending the forearm. The treatment consists in relaxing the Triceps by 
extending the limb, and retaining it in the extended position by means of a long straight splint 
applied to the front of the arm; the fragments are thus brought into close apposition, and 
may be further approximated by drawing down the upper fragment. Union is generally 
ligamentous. 
Fracture of the neck of the radius is an exceedingly rare accident, and is generally caused 
by direct violence. Its diagnosis is somewhat obscure, on account of the slight deformity visible, 
the injured part being surrounded by a large number of muscles; but the movements of prona- 
tion and supination are entirely lost. The upper fragment is drawn outward by the Supinator 
Fig. 335.-Fracture of the humerus above 
the condyles. 
Fig. 336.-Fracture of the olecranon. 
brevis, the extent of displacement being limited by the attachment of the orbicular ligament. 
The lower fragment is drawn forward and slightly upward by the Biceps, and inward by the 
Pronator radii teres, its displacement forward and upward being counteracted in some degree 
by the Supinator brevis. The treatment essentially consists in relaxing the Biceps, Supinator 
brevis, and Pronator radii teres muscles by flexing the forearm, and placing it in a position mid- 
way between pronation and supination, extension having been previously made so as to bring 
the parts in apposition. 
In fracture of the radius below the insertion of the Biceps, but above the insertion of the 
Pronator radii teres, the upper fragment is strongly supinated by the Biceps and Supinator 
brevis, and at the same time drawn forward and flexed by the Biceps; the lower fragment is 
pronated and drawn inward toward the ulna by the pronators. Thus there is extreme dis- 
placement with very little deformity. In treating such a fracture the arm must be put up in 
a position of supination, otherwise union will take place with great impairment of the move- 
ments of the hand. In fractures of the radius below the insertion of the Pronator radii teres 
(Fig. 337), the upper fragment is drawn upward by the Biceps and inward by the Pronator 
radii teres, holding a position midway between pronation and supination, and a degree of fulness 
in the upper half of the forearm is thus produced; the lower fragment is drawn downward and 
inward toward the ulna by the Pronator quadratus, and thrown into a state of pronation by the 
same muscle; at the same time, the Supinator longus, by elevating the styloid process, into which 506 
THE MUSCLES AND FASCIAE 
it is inserted, will serve to depress the upper end of the lower fragment still more toward the ulna. 
In order to relax the opposing muscles the forearm should be bent, and the limb placed in a 
position midway between pronation and supination; the fracture is then easily reduced by 
extension from the wrist and elbow: well-padded splints should be applied on both sides of 
the forearm from the elbow to the wrist; the hand being allowed to fall, will, by its own weight, 
counteract the action of the Pronator quadratus and Supinator longus, and elevate the lower 
fragment to the level of the upper one. 
In fracture of the shaft of the ulna the upper fragment retains its usual position, but the 
lower fragment is drawn outward toward the radius by the Pronator quadratus, producing a 
well-marked depression at the seat of fracture and some fulness on the dorsal and palmar sur- 
faces of the forearm The fracture is easily 
reduced by extension from the wrist and fore- 
arm. The forearm should be flexed, and 
placed in a position midway between pronation 
and supination, and well-padded splints ap- 
plied from the elbow to the ends of the fingers. 
In fracture of the shafts of the radius and 
ulna together the lower fragments are drawn 
upward, sometimes forward, sometimes back- 
ward, according to the direction of the frac- 
ture, by the combined actions of the Flexor and 
Extensor muscles, producing a degree of ful- 
ness on the dorsal or palmar surface of the 
forearm; at the same time the two fragments are drawn into contact by the Pronator quad- 
ratus, the radius being in a state of pronation : the upper fragment of the radius is drawn 
upward and inward by the Biceps and Pronator radii teres to a higher level than the ulna; 
the upper portion of the ulna is slightly elevated by the Brachialis anticus. The fracture may 
be reduced by extension from the wrist and elbow, and the forearm should be placed in the 
same position as in fracture of the ulna. 
In fracture of the lower end of the radius {Colles'' fracture} (Fig. 338) the displacement 
which is produced is very considerable, and bears some resemblance to dislocation of the 
carpus backward, from which it should be carefully distinguished. The lower fragment is 
displaced backward and upward, but this displacement is probably due to the force of the 
blow driving the portion of the bone into this position and not to any muscular influence. 
The upper fragment projects forward, often lacerating the substance of the Pronator quad- 
ratus, and is drawn by this muscle into close contact with the lower end of the ulna, causing a 
Fig. 337.-Fracture of the shaft of the radius. 
Fig. 338.-Fracture of the lower end of the radius. 
projection on the anterior surface of the forearm, immediately above the carpus, from the flexor 
tendons being thrust forward. This fracture may be distinguished from dislocation by the 
deformity being removed on making sufficient extension, when crepitus may be occasionally 
detected; at the same time, on extension being discontinued, the parts immediately resume 
their deformed appearance. The age of the patient will also assist in determining whether 
the injury is fracture or separation of the epiphysis. Reduction is effected by hyperextension, 
longitudinal traction, and forced flexion.1 The posterior straight splint with suitable pads is 
the best dressing. 
1 R. J. Levis. OF THE LOWER EXTREMITY 
507 
MUSCLES AND FASCIA OF THE LOWER EXTREMITY 
The Muscles of the Lower Extremity are subdivided into groups corresponding 
with the different regions of the limb. 
I. Iliac Region. 
Psoas magnus. 
Psoas parvus. 
Iliacus. 
II. Thigh. 
1. Anterior Femoral Region. 
Tensor fasciae Femoris. 
Sartorius. 
6. Posterior Tibio-fibular Region. 
Superficial Layer. 
Gastrocnemius. 
Soleus. 
Plantaris. 
Deep Layer. 
Popliteus. 
Flexor longus hallucis. 
Flexor longus digitorum. 
Tibialis posticus. 
7. Fibular Region. 
Peroneus longus. 
Peroneus brevis. 
IV. Foot. 
8. Dorsal Region. 
Extensor brevis digitorum. 
9. Plantar Region. 
First Layer. 
Abductor hallucis. 
Flexor brevis digitorum. 
Abductor minimi digiti. 
Second Layer. 
Flexor accessorius. 
Lumbricales. 
Third Layer. 
Flexor brevis hallucis. 
Adductor obliquus hallucis. 
Flexor brevis minimi digiti. 
Adductor transversus hallucis. 
Fourth Layer. 
The Interossei- 
Quadriceps 
extensor. 
Rectus. 
Vastus externus. 
Vastus internus. 
Crureus. 
Subcrureus. 
2. Internal Femoral Region. 
Gracilis. 
Pectineus. 
Adductor longus. 
Adductor brevis. 
Adductor magnus. 
3. Gluteal Region. 
Gluteus maximus. 
Gluteus medius. 
Gluteus minimus 
Pyriformis. 
Obturator internus. 
Gemellus superior. 
Gemellus inferior. 
Quadratus femoris. 
Obturator externus. 
4. Posterior Femoral Region. 
Biceps. 
Semitendinosus. 
Semimembranosus. 
III. Leg. 
5. Anterior Tib io-fibular Region. 
Tibialis anticus. 
Extensor proprius hallucis. 
Extensor longus digitorum. 
Peroneus tertius. 508 
THE MUSCLES AND FASCIAE 
I. MUSCLES AND FASCIA OF THE ILIAC REGION. 
Psoas magnus. Psoas parvus. Iliacus. 
Dissection.-No detailed description is required for the dissection of these muscles. On 
the removal of the viscera from the abdomen they are exposed, covered by the peritoneum and 
a thin layer of fascia, the iliac fascia. 
Iliac Fascia (fascia iliaca).-The iliac fascia1 is the aponeurotic layer which 
lines the back part of the abdominal cavity, and covers the Psoas and Iliacus 
muscles throughout their whole extent. It is thin above, and becomes gradually 
thicker below as it approaches the crural arch. 
The Portion Covering the Psoas is attached, above, to the ligamentum arcuatum 
internum; internally, by a series of arched processes to the intervertebral sub- 
stances and prominent margins of the bodies of the vertebrae, and to the upper part 
of the sacrum, the intervals so left, opposite the constricted portions of the bodies, 
ILIACUS 
PELVIC 
PERITONEUM 
FASCIA ILIACA 
EXTRA-PERITONEAL 
TISSUE 
PELVIC FASCIA 
PARIETAL LAYER 
OF PELVIC FASCIA 
VISCERAL LAYER 
OF PELVIC FASCIA 
FASCIAL CANAL 
FAT OF ISCHIO- 
RECTAL FOSSA 
ANAL 
FASCIA 
SPHINCTER 
ANI EXTERNUS 
Fig. 339.-Oblique section across the pelvis, to show the disposition of the pelvic fascia and the 
boundaries of the ischio-rectal fossa. (Cunningham.) 
transmitting the lumbar arteries and veins and filaments of the sympathetic cord. 
Externally, above the crest of the ilium, this portion of the iliac fascia is continu- 
ous with the anterior lamella of the lumbar fascia, but below the crest of the 
ilium it is continuous with the fascia covering the Iliacus. 
The Portion Investing the Iliacus is connected externally to the whole length 
of the inner border of the crest of the ilium, and internally to the brim of the true 
pelvis, where it is continuous with the periosteum; and at the ilio-pectineal emi- 
nence it receives the tendon of insertion of the Psoas parvus, when that muscle 
exists. External to the femoral vessels, this fascia is intimately connected to the 
posterior margin of Poupart's ligament, and is continuous with the fascia transver- 
salis. Immediately to the outer side of the femoral vessels the fascia iliaca is pro- 
longed backward and inward from Poupart's ligament as a band, the ilio-pectineal 
ligament, which is attached to the ilio-pectineal eminence. This ligament divides 
the space between Poupart's ligament and the innominate bone into two parts, the 
inner of which (lacuna vasorum) transmits the femoral vessels, and contains the 
1 The student must not confound this fascia with the iliac portion of the fascia lata (see p. 515). THE ILIAC REGION 
509 
margin of Gimbernat's ligament and also the femoral ring; the outer (lacuna 
musculorum) the ilio-psoas and the anterior crural nerve (Fig. 340). Internal to 
the vessels the iliac fascia is attached to the ilio-pectineal line behind the con- 
joined tendon, where it is again continuous with the transversalis fascia; and, 
corresponding to the point where the femoral vessels pass into the thigh, this 
fascia descends behind them, forming the posterior wall of the femoral sheath. 
This portion of the iliac fascia which passes behind the femoral vessels is also 
attached to the ilio-pectineal line beyond the limits of the attachment of the con- 
joined tendon; at this part it is continuous with the pubic portion of the fascia lata 
of the thigh. The external iliac vessels lie in front of the iliac fascia, but all the 
branches of the lumbar plexus behind it; it is separated from the peritoneum by a 
quantity of loose areolar tissue. The femoral or crural sheath (fascia cruris) is 
POUPART'S 
LIGAM ENT 
ANTERIOR 
CRURAL NERVE 
-FEMORAL ARTERY 
ILIAC FASCIA 
FEMORAL VEIN 
GIMBERNAT'S 
LIGAMENT 
PECTINEUS 
Fig. 340.-Poupart's ligament and the relation of the parts passing beneath it. (Poirier and Charpy.) 
formed by the transversalis fascia in front of the vessels and the iliac fascia back 
of them. The fascia? join to the inner side of the femoral vein, a space, the 
femoral canal, intervening between the vein and the junction. 
Between the femoral vein and the edge of Gimbernat's ligament is the femoral or 
crural ring (annulus femoralis) (Fig. 342). The crural or femoral canal (canalis 
femoralis) is the interval between the femoral vein and the inner wall of the femoral 
(crural) sheath. This canal extends from the femoral ring to the saphenous 
opening. The femoral ring is closed by the septum crurale of Cloquet (septum 
f emorale [Cloqueti]), which is a process of transversalis fascia. 
The Psoas Magnus (m. psoas major) (Fig. 343) is a long fusiform muscle placed 
on the side of the lumbar region of the spine and the margin of the pelvis. It arises 
from the front of the bases and lower borders of the transverse processes of the 510 
THE MUSCLES AND FASCIAE 
lumbar vertebne by five fleshy slips; also from the sides of the bodies and the corre- 
sponding intervertebral substances of the last dorsal and all the lumbar vertebne. 
The muscle is connected to the bodies of the vertebrae by five slips; each slip is 
attached to the upper and lower margins of two vertebrae, and to the intervertebral 
substance between them, the slips themselves being connected by the tendinous 
arches which extend across the constricted part of the bodies, and beneath which 
pass the lumbar arteries and veins and filaments of the sympathetic cord. These 
tendinous arches also give origin to muscular fibres, and protect the blood-vessels 
and nerves from pressure during the action of the muscle. The first slip is attached 
to the contiguous margins of the last dorsal and first lumbar vertebrae; the last 
to the contiguous margins of the fourth and fifth lumbar vertebrae, and to the 
intervertebral substance. From these points the muscle descends across the 
brim of the pelvis, and, diminishing gradually in size, passes beneath Pou- 
part's ligament, and terminates in a tendon which, after receiving nearly the 
whole of the fibres of the Iliacus, is inserted into the lesser trochanter of the 
femur. 
Relations.-In the lumbar region: by its anterior surface, which is placed behind 
the peritoneum, with the iliac fascia, the ligamentum arcuatuminternum, the kidney, 
Psoas parvus, renal vessels, ureter, spermatic vessels, genito-crural nerve, and the 
colon. In many cases the vermiform appendix rests upon the Psoas muscle (page 
511). By its posterior surface, with the transverse processes of the lumbar vertebne 
and the Quadratus lumborum muscle, from which it is separated by the anterior 
lamella of the lumbar fascia. The lumbar plexus is situated in the posterior part 
of the substance of the muscle. By its inner side the muscle is in relation with the 
bodies of the lumbar vertebne, the lumbar arteries, the ganglia of the sympathetic 
nerve, and their branches of communication with the spinal nerves; the lumbar 
glands; the vena cava inferior on the right and the aorta on the left side, and along 
the brim of the pelvis with the external iliac artery. In the thigh it is in relation, 
in front, with the fascia lata; behind, with the capsular ligament of the hip, from 
which it is separated by a synovial bursa (bursa ilio-pectinea), which frequently 
communicates with the cavity of the joint through an opening of variable size; 
between the tendon and part of the lesser trochanter is the bursa iliaca sub- 
tendinea ; by its inner border, with the Pectineus and internal circumflex artery, 
and also with the femoral artery, which slightly overlaps it: by its outer border, 
with the anterior crural nerve and Iliacus muscle. 
The Psoas Parvus (m. psoas minor) (Fig. 343) is a long slender muscle placed 
in front of the Psoas magnus. It arises from the sides of the bodies of the last 
dorsal and first lumbar vertebrae and from the intervertebral substance between 
them. It forms a small flat muscular bundle, which terminates in a long flat 
tendon inserted into the ilio-pectineal eminence, and, by its outer border, into 
the iliac fascia. This muscle is often absent, and, according to Cruveilhier, is 
sometimes double. 
Relations.-It is covered by the peritoneum, and, at its origin, by the ligamentum 
arcuatum internum; it rests on the Psoas magnus. 
The Iliacus (Fig. 343) is a flat, triangular muscle which fills up the whole of the 
iliac fossa. It arises from the upper two-thirds of this fossa and from the inner 
margin of the crest of the ilium; behind, from the ilio-lumbar ligament and base 
of the sacrum; in front, from the anterior superior and anterior inferior spinous 
processes of the ilium, from the notch between them. The fibres converge to be 
inserted into the outer side of the tendon of the Psoas, some of them being pro- 
longed on to the shaft of the femur for about an inch below and in front of the 
lesser trochanter.1 The most external fibres are inserted into the capsule of the 
1 The Psoas magnus, Psoas parvus, and Iliacus are regarded by His and others as a single muscle, the Ilio- 
psoas (Fig. 340). THE ILIAC REGION 
511 
hip-joint. If these fibres are separate they constitute the Ilio-capsularis muscle or 
the Iliacus minor. 
Relations.-Within the abdomen: by its anterior surface, with the iliac fascia, 
which separates the muscle from the peritoneum, and with the external cutaneous 
nerve; on the right side, with the caecum; on the left side, with the sigmoid flexure 
of the colon; by its posterior surface, with the iliac fossa; by its inner border, with 
the Psoas magnus and anterior crural nerve. In the thigh, it is in relation, by its 
anterior surface, with the fascia lata, the Rectus and Sartorius muscles, and the 
profunda femoris artery; behind, with the capsule of the hip-joint, a synovial 
bursa common to it and the Psoas magnus being interposed. 
Nerves.-The Psoas magnus is supplied by the anterior branches of the second 
and third lumbar nerves; the Psoas parvus, when it exists, is supplied by the 
anterior branch of the first lumbar nerve; and the Iliacus by the anterior branches 
of the second and third lumbar nerves through the anterior crural. 
Actions.-The Psoas and Iliacus muscles, acting from above, flex the thigh 
upon the pelvis. Acting from below, the femur being fixed, the muscles of 
both sides bend the lumbar portion of the spine and pelvis forward. They also 
serve to maintain the erect position, by supporting the spine and pelvis upon 
the femur, and assist in raising the trunk when the body is in the recumbent 
posture. 
The Psoas parvus is a tensor of the iliac fascia. It assists in flexing the lumbar 
spine laterally, the pelvis being its fixed point. 
Surgical Anatomy.-There is no definite septum between the portions of the iliac fascia 
covering the Psoas and Iliacus respectively, and the fascia is only connected to the subjacent 
muscles by a quantity of loose connective tissue. When an abscess forms beneath this fascia, 
as it is very apt to do, the matter is contained in an osseo-fibrous cavity, which is closed on all 
sides within the abdomen, and is open only at its lower part, where the fascia is prolonged over 
the muscle into the thigh. 
Abscess within the sheath of the Psoas muscle (psoas abscess') is generally due to tuberculous 
caries of the bodies of the lower dorsal or of the lumbar vertebrae. When the disease is in the dorsal 
region, the matter tracts down the posterior mediastinum, in front of the bodies of the vertebrae, 
and, passing beneath the ligamentum arcuatum internum, enters the sheath of the Psoas muscle, 
down which it passes as far as the pelvic brim; it then gets beneath the iliac portion of the fascia 
and fills up the iliac fossa. In consequence of the attachment of the fascia to the pelvic brim, it 
rarely finds its way into the pelvis, but passes by a narrow opening under Poupart's ligament 
into the thigh, to the outer side of the femoral vessels. It thus follows that a Psoas abscess may 
be described as consisting of four parts: (1) a somewhat narrow channel at its upper part, in the 
Psoas sheath; (2) a dilated sac in the iliac fossa; (3) a constricted neck under Poupart's ligament; 
and (4) a dilated sac in the upper part of the thigh. When the lumbar vertebrae are the seat of the 
disease, the matter finds its way directly into the substance of the muscle. If a Psoas abscess 
forms the muscular fibres are destroyed, and the nervous cords contained in the abscess are isolated 
and exposed in its interior; the femoral vessels which lie in front of the fascia remain intact, and 
the peritoneum seldom becomes implicated. All Psoas abscesses do not, however, pursue this 
course: the matter may leave the muscle above the crest of the ilium, and, tracking backward, 
may point in the loin (lumbar abscess); or it may point above Poupart's ligament in the inguinal 
region; or it may follow the course of the iliac vessels into the pelvis, and, passing through the 
great sacro-sciatic notch, discharge itself on the back of the thigh; it may open into the bladder 
or find its way into the perinseum, or it may pass down the thigh to the popliteal space or even 
lower. Strain of the Psoas muscle is not unusual, and induces pain which may be mistaken 
for appendicitis. The bursa beneath the tendon of the Psoas and Iliacus and the hip-joint or 
that between the tendon and the lesser trochanter may greatly enlarge and produce pain and 
disablement. Byron Robinson1 pointed out that trauma of the Psoas muscle may be an 
important factor in the etiology of appendicitis, trauma may induce periappendicular adhe- 
sions and adhesions interfere with the circulation of blood and ffeces. Robinson says, in the 
previously quoted article, that in 46 per cent, of men and in 20 per cent, of women the 
appendix rests on the Psoas muscle. 
1 Annals of Surgery, April, 1901. THE MUSCLES AND FASCIA 
512 
II. MUSCLES AND FASCIA! OF THE THIGH. 
1. The Anterior Femoral Region. 
Tensor fasciae femoris. 
Sartorius. 
Quadriceps 
extensor. 
Rectus. 
Vastus externus. 
Vastus internus. 
Crureus. 
Subcrureus. 
Dissection.-To expose the muscles and fasciae in this region, make an incision along 
Poupart's ligament, from the anterior superior spine of the ilium to the spine of the os pubis; 
a vertical incision from the centre of this, along the middle of the thigh to below the knee-joint; 
and a transverse incision from the inner to the outer side of the leg, at the lower end of the ver- 
tical incision. The flaps of integument having been removed, the superficial and deep fasciae 
should be examined. The more advanced student should commence the study of this region by 
an examination of the anatomy of femoral hernia and Scarpa's triangle, the incisions for the 
dissection of which are marked out in Fig. 341. 
Superficial Fascia.-The superficial fascia forms a continuous layer over the 
whole of the thigh. It consists of areolar tissue, containing in its meshes much fat, 
and is capable of being separated into two or 
more layers, between which are found the super- 
ficial vessels and nerves. It varies in thickness 
in different parts of the limb: in the groin it 
is thick, and the two layers are separated from 
one another by the superficial inguinal lymphatic 
glands, the internal saphenous vein, and several 
smaller vessels. One of these two layers, the 
superficial, is continuous above with the super- 
ficial fascia of the abdomen and the back. In- 
ternally it is continuous with the superficial 
fascia of the perineum. The deep layer of the 
superficial fascia is a very thin fibrous layer, 
best marked on the inner side of the long 
saphenous vein and below Poupart's ligament. 
It is placed beneath the subcutaneous vessels 
and nerves and upon the surface of the fascia 
lata. It is intimately adherent to the fascia lata 
a little below Poupart's ligament. It covers the 
saphenous opening (Fig. 342) in the fascia lata, 
being closely united to the margins of the open- 
ing, and is connected to the sheath of the fem- 
oral vessels by its under surface. The portion 
of the fascia covering this aperture is perforated 
by the internal saphenous vein and by numer- 
ous blood- and lymphatic vessels; hence it has 
been termed the cribriform fascia fascia cribrosa), 
theopenings for these vessels having been likened 
to the holes in a sieve. The cribriform fascia 
adheres closely both to the superficial fascia and 
to the fascia lata, so that it is described by some 
anatomists as partof the fascia lata, but is usually 
considered (as in this work) as belonging to the 
superficial fascia. It is not until the cribriform 
fascia has been cleared away that the saphenous opening is seen, so that this open- 
ing does not in ordinary cases exist naturally, but is the result of dissection. Mr. 
1. Dissection of 
femoral hernia, 
and Scarpa's 
triangle. 
. 
tront of thigh. 
3. Front of leg. 
-4- Dorsum of foot. 
Fig. 341, Dissection^ oHower extremity. THE ANTERIOR FEMORAL REGION 
Callender, however, speaks of cases in which, probably as the result of pressure 
from enlarged inguinal lymphatic glands, the fascia has become atrophied, and a 
saphenous opening exists independent of dissection. A femoral hernia in passing 
through the saphenous opening receives the cribriform fascia as one of its cover- 
ings. A large subcutaneous bursa (bursa prepatellar is subcutanea) is found in the 
superficial fascia over the patella, and another (bursa trochanterica subcutanea) 
in the superficial fascia over the great trochanter. 
Deep Fascia or Fascia Lata (Fig. 342).- 1 he deep fascia of the thigh is exposed 
on the removal of the superficial fascia, and is named, from its great extent, the fascia 
lata; it forms a uniform investment for the whole of this region of the limb, but varies 
in thickness in different parts; thus, it is thicker in the upper and outer part of 
the thigh, where it receives a fibrous expansion from the Gluteus maximus muscle, 
and the Tensor fasciae femoris is inserted between its layers: it is very thin behind, 
and at the upper and inner part where it covers the Adductor muscles, and again 
513 
POUPART'S 
LIGAMENT 
INTERCOLUMNAR 
FIBRES 
FEMORAL 
RING' 
EXTERNAL 
'ABDOMINAL 
RING 
GIM BERNAT'S. 
LIGAMENT 
SAPHENOUS 
OPENING 
FEMORAL 
vein" 
LONG- 
SAPHENOUS 
VEIN 
Fig. 342.-Right external abdominal ring and saphenous opening in the male. (Spalteholz). 
becomes stronger around the knee, receiving fibrous expansions from the tendon of 
the Biceps externally, from the Sartorius internally, and from the Quadriceps 
extensor in front. The fascia lata is attached, above and behind, to the back of 
the sacrum and coccyx; externally, to the crest of the ilium; in front, to Pou- 
part's ligament and to the body of the os pubis; and internally, to the descend- 
ing ramus of the os pubis, to the ramus and tuberosity of the ischium, and to the 
lower border of the great sacro-sciatic ligament. From its attachment to the crest 
of the ilium it passes down over the Gluteus medius muscle to the upper border 
of the Gluteus maximus, where it splits into two layers, one passing superficial to 
and the other beneath this muscle. At the lower border of the muscle the two layers 
reunite. Externally the fascia lata receives the greater part of the tendon of inser- 
tion of the Gluteus maximus, and becomes proportionately thickened. The 
portion of the fascia lata arising from the front part of the crest of the ilium, cor- THE MUSCLES AND FASCJHJ 
514 
responding to the origin of the Tensor fasciie 
femoris, passes down the outer side of the thigh 
as two layers, one superficial to and the other 
beneath this muscle. The deep layer is a con- 
tinuation of the tendinous fibres of the Gluteus 
maximus muscle and the superficial layer is 
chiefly a continuation of the tendinous fibres of 
the Tensor fasciae femoris, but receives some 
fibres from the fascia covering the Gluteus 
medius muscle.1 These layers at the lower 
end of the muscle become blended into a thick 
and strong band, having first received the in- 
sertion of the muscle. This band is continued 
downward, under the name of the ilio-tibial band 
(tractus iliotibialis [Maissiati]), to be inserted 
into the external tuberosity of the tibia. A 
strengthening band of transverse fibres is placed 
in the gluteal groove or sulcus (sulcus glutceus) and 
another is placed across the roof of the popliteal 
space. Below, the fascia lata is attached to all 
the prominent points around the knee-joint- 
viz., the condyles of the femur, tuberosities of 
the tibia, and head of the fibula. On each side 
of the patella it is strengthened by transverse 
fibres given off from the lower part of the Vasti 
muscles, which are attached to and support this 
bone. Of these the outer fibres are the stronger, 
and are continuous with the ilio-tibial band. 
From the inner surface of the fascia lata are 
given off two strong intermuscular septa, which 
are attached to the whole length of the linea 
aspera and its prolongations above and below: 
the external intermuscular septum (septum in- 
termusculare laterale) is the stronger. It extends 
from the insertion of the Gluteus maximus to 
the outer condyle, separates the Vastus externus 
in front from the short head of the Biceps be- 
hind, and gives partial origin to these muscles; 
the internal intermuscular septum (septum inter- 
musculare mediate}, the thinner of the two, 
separates the Vastus internus from the Adductor 
and Pectineus muscles. Besides these there 
are numerous smaller septa, separating the in- 
dividual muscles and enclosing each in a dis- 
tinct sheath. At the upper and inner part of 
the thigh, a little below Poupart's ligament, a 
large oval-shaped aperture is observed after 
the superficial fascia has been cleared off: it 
transmits the internal saphenous vein and other 
smaller vessels, and is termed the saphenous 
opening (fossa ovalis) (Fig- 342). This opening 
is covered by a portion of the deep layer of the 
Fig. 343.-Muscles of the iliac and anterior 
femoral region. 
1 Werner Spalteholz's Hand Atlas of Human Anatomy. Edited 
and translated by Lewellys F. Barker. THE ANTERIOR FEMORAL REGION 
515 
superficial fascia, the cribriform fascia. In order more correctly to consider the 
mode of formation of this aperture, the fascia lata in this part of the thigh is 
described as consisting of two portions-an iliac portion and a pubic portion. 
Iliac Portion.-The iliac portion, the superficial layer of the fascia lata or the 
Sartorial portion of the fascia lata, is all that part of the fascia lata on the outer 
side of the saphenous opening. It is attached, externally, to the crest of the 
ilium and its anterior superior spine, to the whole length of Poupart's ligament as 
far internally as the spine of the os pubis, and to the pectineal line in conjunction 
with Gimbernat's ligament. From the spine of the os pubis it is reflected down- 
ward and outward, forming an arched margin, the falciform process or the falciform 
margin of Burns (margo jalcijormis), or the superior cornu of the saphenous opening 
(cornu superius). This margin overlies and is adherent to the anterior layer of 
the sheath of the femoral vessels: to its edge is attached the cribriform fascia; 
and, below, it is continuous with the pubic portion of the fascia lata. 'The 
femoral ligament, or the ligament of Hey, is the point at which the falciform 
process joins the base of Gimbernat's ligament. 
Pubic Portion.-The pubic portion, or the pectineal portion, or the deep layer of 
the fascia lata, is situated at the inner side of the saphenous opening: at the lower 
margin of this aperture it is continuous with the iliac portion. The lower concave 
margin of the saphenous opening where the two layers of fascia are continuous is 
called the inferior cornu {cornu injerius). Traced upward, the pubic portion covers 
the surface of the Pectineus, Adductor longus, and Gracilis muscles, and, passing 
behind the sheath of the femoral vessels, to which it is closely united, is continu- 
ous with the sheath of the Psoas and Iliacus muscles, and is attached above to 
the ilio-pectineal line, where it becomes continuous with the iliac fascia. From 
this description it may be observed that the iliac portion of the fascia lata passes 
in front of the femoral vessels, and the pubic portion behind them, so that an 
apparent aperture exists between the two, through which the internal saphenous 
joins the femoral vein.1 
Surgical Anatomy.-The ilio-tibial band at a point between the crest of the ilium and the 
great trochanter is so tense that it is impossible to sink the fingers in deeply in this region. Dr. 
Allis points out that in fracture of the neck of the femur the great trochanter mounts toward 
the iliac crest, the ilio-tibial band relaxes, and the fingers can be sunk deeply into the space 
between the great trochanter and the iliac crest-Allis's sign. Allis's sign indicates shorten- 
ing. A Psoas abscess usually points at the termination of the Psoas muscle, but the tuberculous 
matter may be directed down the thigh beneath the fascia lata, and it may reach the popliteal 
space or even lower. 
The fascia should now be removed from the surface of the muscles. This may be effected by 
pinching it up between the forceps, dividing it, and separating it from each muscle in the course 
of its fibres. 
The Tensor Fasciae Femoris (m. tensor justice latoe, m. tensor vaginae Uemoris') 
(Fig. 343) arises from the anterior part of the outer lip of the crest of the ilium, 
and from the outer surface of the anterior superior spinous process, and part of 
the outer border of the notch below it, between the Gluteus medius and Sartorius, 
and from the surface of the fascia covering the Gluteus medius. It is inserted 
between two layers of the fascia lata, about one-fourth down the outer side of 
the thigh. From the point of insertion the fascia is continued downward to the 
external tuberosity of the tibia as a thickened band, the ilio-tibial band. 
Relations.-By its superficial surface, with the fascia lata and the integument; 
by its deep surface, with the Gluteus medius, Rectus femoris, and Vastus externus 
muscles, and the ascending branches of the external circumflex artery; by its 
anterior border, with the Sartorius, from which it is separated below by a triangular 
1 These parts will be again more particularly described with the anatomy of Hernia. THE MUSCLES AND FASCIA 
516 
space, in which is seen the Rectus femoris; by its posterior border, with the 
Gluteus medius. 
The Sartorius (Fig. 343), the longest muscle in the body, is flat, narrow, and 
ribbon-like; it arises by tendinous fibres from the anterior superior spinous process 
of the ilium and the upper half of the notch below it, passes obliquely across the 
upper and anterior part of the thigh, from the outer to the inner side of the limb, 
then descends vertically, as far as the inner side of the knee, passing behind the 
inner condyle of the femur, and terminates in a tendon which, curving obliquely 
forward, expands into a broad aponeurosis, inserted in front of the Gracilis and 
Semitendinosus, into the upper part of the inner surface of the shaft of the tibia, 
nearly as far forward as the crest. The upper part of the tendon is curved back- 
ward over the upper edge of the tendon of the Gracilis so as to be inserted behind 
it. An offset is derived from the upper margin of this aponeurosis, which blends 
with the fibrous capsule of the knee-joint, and another, given off from its lower 
border, blends with the fascia on the inner side of the leg. 
The relations of this muscle to the femoral artery should be carefully examined, 
as it constitutes the chief guide in tying the vessel. In the upper third of the 
thigh it forms the outer side of a triangular space, Scarpa's triangle (trigonum 
femorale), the inner side of which is formed by the inner border of the Adductor 
longus, and the base, which is turned upward, by Poupart's ligament; the femoral 
artery passes perpendicularly through the middle of this space from its base to 
its apex. In the middle third of the thigh the femoral artery lies first along 
the inner border, and then behind the Sartorius. 
Relations.-By its superficial surface, with the fascia lata and integument; by 
its deep surface, with the Rectus, Iliacus, Vastus internus, anterior crural nerve, 
sheath of the femoral vessels, Adductor longus, Adductor magnus, Gracilis, 
Semitendinosus, long saphenous nerve, and internal lateral ligament of the knee- 
joint. Frequently there is a bursa (bursa m. sartorii propria) between the tendon 
of the Sartorius and the tendons of the Gracilis and Semimembranosus. It may 
be in communication with the bursa anserina. 
The Quadriceps Extensor (m. quadriceps femoris) (Fig. 343) includes the four 
remaining muscles on the front of the thigh. It is the great Extensor muscle 
of the leg, forming a large fleshy mass which covers the front and sides of the 
femur, being united below into a single tendon, attached to the patella, and 
above subdivided into separate portions, which have received distinct names. 
Of these, one occupying the middle of the thigh, connected above with the ilium, 
is called the Rectus femoris, from its straight course. The other divisions lie in 
immediate connection with the shaft of the femur, which they cover from the 
trochanters to the condyles. The portion on the outer side of the femur is 
termed the Vastus externus; that covering the inner side, the Vastus internus; 
and that covering the front of the femur, the Crureus. 
The Rectus Femoris is situated in the middle of the anterior region of the thigh; 
it is fusiform in shape, and its superficial fibres are arranged in a bipenniform 
manner, the deep fibres running straight down to the deep aponeurosis. It arises 
by two tendons: one, the anterior or straight, from the anterior inferior spinous 
process of the ilium; the other, the posterior or reflected tendon, from a groove 
above the brim of the acetabulum; the two unite at an acute angle and spread 
into an aponeurosis, which is prolonged downward on the anterior surface of the 
muscle and from which the muscular fibres arise.1 The muscle terminates in a 
broad and thick aponeurosis, which occupies the lower two-thirds of its posterior 
surface, and, gradually becoming narrowed into a flattened tendon, is inserted 
1 Mr. W. R. Williams, in an interesting paper in the Journ. of Anat, and Phys., vol. xiii. p. 204, points 
out that the reflected tendon is the real origin of the muscle, and is alone present in early foetal life. The 
direct tendon is merely an accessory band of condensed fascia. The paper will well repay perusal, though in 
some particulars I think the description in the text more generally accurate.-Ed. of 15th English edition. THE ANTERIOR FEMORAL REGION 
517 
into the patella in common with the Vasti and Crureus. Beiween the tendon of 
origin and the acetabulum there is often a bursa (bursa m. recti femoris). 
Relations.-By its superficial surface, with the anterior fibres of the Gluteus 
minimus, the Tensor fasciae femoris, the Sartorius, and the Iliacus; by its lower 
three-fourths, with the fascia lata. By its posterior surface, with the hip-joint, 
the external circumflex vessels, branches of the anterior crural nerve, and the 
Crureus and Vasti muscles. 
The Vastus Extemus (m. vastus lateralis) is the largest part of the Quadriceps 
extensor. It arises by a broad aponeurosis, which is attached to the upper half 
of the anterior intertrochanteric line, to the anterior and inferior borders of the 
root of the great trochanter, to the outer lip of the gluteal ridge, and to the upper 
half of the outer lip of the linea aspera; this aponeurosis covers the upper three- 
fourths of the muscle, and from its inner surface many fibres take origin. A few 
additional fibres arise from the tendon of the Gluteus maximus, and from the 
external intermuscular septum between the Vastus externus and short head of the 
Biceps. The fibres form a. large fleshy mass, which is attached to a strong aponeu- 
rosis, placed on the under surface of the muscle at its lower part: this becomes 
contracted and thickened into a flat tendon, which is inserted into the outer 
border of the patella, blending with the great Extensor tendon, and giving an 
expansion to the capsule of the knee-joint. Some of the fibres run down by the 
side of the patella to the condyle of the tibia, and are called the retinacula patellae 
laterale. 
Relations.-By its superficial surface, with the Rectus, the Tensor fasciae femoris, 
the fascia lata, and the tendon of the Gluteus maximus, from which it is separated 
by a synovial bursa. By its deep surface, with the Crureus, some large branches 
of the external circumflex artery and anterior crural nerve being interposed. 
The Vastus Internus and Crureus appear to be inseparably united, but when 
the Rectus femoris has been reflected, a narrow interval will be observed extending 
upward from the inner border of the patella between the two muscles. Here they 
can be separated, and the separation should be continued upward as far as the 
lower part of the anterior intertrochanteric line, where, however, the two muscles 
are frequently continuous. 
The Vastus Internus (m. vastus medial is) arises from the lower half of the 
anterior intertrochanteric line, the spiral line, the inner lip of the linea aspera, 
the upper part of the internal supra-condylar line, and the tendon of the Adductor 
magnus and the internal intermuscular septum. Its fibres are directed downward 
and forward, and are chiefly attached to an aponeurosis which lies on the deep 
surface of the muscle and is inserted into the inner border of the patella and 
the Quadriceps extensor tendon, an expansion being sent to the capsule of the 
knee-joint. Some of the fibres run down by the side of the patella to the con- 
dyle of the tibia and are called the retinacula patellae mediale. 
The Crureus (m. vastus intermedins) arises from the front and outer aspect of 
the shaft of the femur in its upper two-thirds and from the lower part of the 
external intermuscular septum. Its fibres end in a superficial aponeurosis, which 
forms the deep part of the Quadriceps extensor tendon. 
Relations.-The inner edge of the Crureus is in contact with the anterior edge 
of the Vastus internus, but when separated from each other, as directed above, the 
latter muscle is seen merely to overlap the inner aspect of the femoral shaft without 
taking any fibres of origin from it. The Vastus internus is partly covered by the 
Rectus and Sartorius, but where these separate near the knee it becomes superficial, 
and produces a well-marked prominence above the inner aspect of the knee. In 
the middle third of the thigh it forms the outer wall of Hunter's canal (canalis 
adductorius [Ilunteri]), which contains the femoral vessels and the long saphenous 
nerve-the roof of the canal being formed by a strong fascia which extends from THE MUSCLES AND FASCIAE 
518 
the Vastus internus to the Adductores longus and magnus. The Crureus is almost 
completely hidden by the Rectus femoris and Vastus externus. The deep surface 
of the two muscles is in relation with the femur and Subcrureus muscles. A 
synovial bursa (bursa suprapatellaris) is situated between the femur and the 
portion of the Quadriceps extensor tendon above the patella; in the adult it 
communicates with the synovial cavity of the knee-joint. 
The tendons of the different portions of the Quadriceps extensor unite at the 
lower part of the thigh, so as to form a single strong tendon, which is inserted into 
the upper part of the patella, some few fibres passing over it to blend with the 
Ligamentum patellae. More properly, the patella may be regarded as a sesamoid 
bone, developed in the tendon of the Quadriceps; and the Ligamentum patellae, 
which is continued from the lower part of the patella to the tuberosity of the tibia, 
as the proper tendon of insertion of the muscle. A synovial bursa, the deep patel- 
lar bursa (bursa infrapatellaris profunda), is interposed between the tendon and 
the upper part of the tuberosity of the tibia; and another, the pre-patellar bursa 
(bursa pros patellar is subcufanea), is placed over the patella itself. This latter 
bursa often becomes enlarged, constituting "housemaid's knee." 
The Subcrureus (m. articularis genu) is a small muscle, usually distinct from 
the Crureus, but occasionally blended with it, which arises from the anterior sur- 
face of the lower part of the shaft of the femur, and is inserted into the upper 
part of the cid-de-sac of the capsular ligament which projects upward beneath 
the Quadriceps for a variable distance. It sometimes consists of several separate 
muscular bundles. 
Nerves.-The Tensor fasciae femoris is supplied by the fourth and fifth lumbar 
and first sacral nerves through the superior gluteal nerve; the other muscles of 
this region, by the second, third, and fourth lumbar nerves, through branches of 
the anterior crural. 
Actions.-The Tensor fasciae femoris is a tensor of the fascia lata; continuing 
its action, the oblique direction of its fibres enables it to abduct and to rotate the 
thigh inward. In the erect posture, acting from below, it will serve to steady the 
pelvis upon the head of the femur, and by means of the ilio-tibial band it steadies 
the condyles of the femur on the articular surfaces of the tibia, and assists the 
Gluteus maximus in supporting the knee in the extended position. The Sartorius 
flexes the leg upon the thigh, and, continuing to act, flexes the thigh upon the 
pelvis; it next rotates the thigh outward. It was formerly supposed to adduct the 
thigh, so as to cross one leg over the other, and hence received its name of Sar- 
torius, or tailor's muscle (sartor, a tailor),because it was supposed to assist in cross- 
ing the legs in the squatting position. When the knee is bent the Sartorius assists 
the Semitendinosus, Semimembranosus, and Popliteus in rotating the tibia inward. 
'Faking its fixed point from the leg, it flexes the pelvis upon the thigh, and, if one 
muscle acts, assists in rotating the pelvis. The Quadriceps extensor extends the 
leg upon the thigh. The Rectus muscle assists the Psoas and Iliacus in supporting 
the pelvis and trunk upon the femur. It also assists in flexing the thigh on the 
pelvis, or if the thigh is fixed it will flex the pelvis. The Vastus internus draws 
the patella inward as well as upward. 
Surgical Anatomy.-A few fibres of the Rectus muscle are liable to be ruptured from 
severe strain. This accident is especially liable to occur during the games of football and cricket, 
and is sometimes known as cricket thigh. The patient experiences a sudden pain in the part, 
as if he had been struck, and the Rectus muscle stands out and is felt to be tense and rigid. The 
accident is often followed by considerable swelling from inflammatory effusion. Occasionally the 
Quadriceps extensor may be torn away from its insertion into the patella, or the tendon of the 
quadriceps may be ruptured about an inch above the bone. This accident is caused in the same 
manner that fracture of the patella by muscular action is produced-viz., by a violent muscular 
effort to prevent falling whilst the knee is in a position of semiflexion. A distinct gap can be THE INTERNAL FEMORAL REGION 
519 
felt above the patella, and, owing to the retraction of the muscular fibres, union may fail to take 
place. Sudden and powerful contraction of the Quadriceps extensor femoris is the cause of 
transverse fracture of the patella. 
2. The Internal Femoral Region 
Gracilis. 
Pectineus. 
Adductor longus. 
Adductor brevis. 
Adductor magnus 
Dissection.-These muscles are at once exposed by removing the fascia from the forepart 
and inner side of the thigh. The limb should be abducted, so as to render the muscles tense 
and easier of dissection. 
The Gracilis (Figs. 343, 346, and 349) is the most superficial muscle on the 
inner side of the thigh. It is thin and flattened, broad above, narrowing and taper- 
ing below. It arises by a thin aponeurosis from the lower half of the margin of the 
symphysis and the anterior half of the pubic arch. The fibres pass vertically down- 
ward, and terminate in a rounded tendon which passes behind the internal condyle 
of the femur, and, curving round the inner tuberosity of the tibia, becomes flattened, 
and is inserted into the upper part of the inner surface of the shaft of the tibia, below 
the tuberosity. A few of the fibres of the lower part of the tendon are prolonged 
into the deep fascia of the leg. The tendon of this muscle is situated immediately 
above that of the Semitendinosus, and its upper edge is overlapped by the tendon 
of the Sartorius, with which it is in part blended. As it passes across the internal 
lateral ligament of the knee-joint it is separated from it by a synovial bursa 
(bursa anserina) common to it and the Semitendinosus muscle. 
Relations.-By its superficial surface, with the fascia lata and the Sartorius below: 
the internal saphenous vein crosses it obliquely near its lower part, lying superficial 
to the fascia lata; the internal saphenous nerve emerges between its tendon and 
that of the Sartorius; by its deep surface, with the Adductor brevis and the Adductor 
magnus and the internal lateral ligament of the knee-joint. 
The Pectineus (Fig. 343) is a flat, quadrangular muscle, situated at the anterior 
part of the upper and inner aspect of the thigh. It arises from the linea ilio-pec- 
tinea, and to a slight extent from the surface of the bone in front of it between the 
pectineal eminence and spine of the os pubis, and from the fascia covering the 
anterior surface of the muscle; the fibres pass downward, backward, and outward, 
to be inserted into a rough line leading from the lesser trochanter to the linea aspera. 
Relations.-By its anterior surface, with the pubic portion of the fascia lata, 
which separates it from the femoral vessels and internal saphenous vein; by its 
posterior surface, with the capsular ligament of the hip-joint, the Adductor brevis 
and Obturator externus muscles, the obturator vessels and nerve being interposed; 
by its outer border, with the Psoas, a cellular interval separating them, through 
which pass the internal circumflex vessels; by its inner border, with the margin of 
the Adductor longus. There is usually a bursa (bursa m. pectinei) between the 
pectineus and the tendon of the psoas and iliacus. 
The Adductor Longus (Figs. 343 and 344), the most superficial of the three 
Adductors, is a flat triangular muscle lying on the same plane as the Pectineus. 
It arises, by a flat narrow tendon, from the front of the os pubis, at the angle of 
junction of the crest with the symphysis; and soon expands into a broad fleshy 
belly, which, passing downward, backward, and outward, is inserted, by an 
aponeurosis, into the linea aspera, between the Vastus interims and the Adductor 
magnus, with both of which it is usually blended. 
Relations.-By its anterior surface, with the fascia lata, the Sartorius, and, near 
its insertion, with the femoral artery and vein; by its posterior surface, with the 
Adductor brevis and magnus, the anterior branches of the obturator nerve, and THE MUSCLES AND FASCIAE 
520 
with the profunda artery and vein near its insertion; by its outer border, with the 
Pectineus; by its inner border, with the Gracilis. 
The Pectineus and Adductor longus should now 
be divided near their origin, and turned down- 
ward, when the Adductor brevis and Obturator ex- 
ternus will be exposed. 
The Adductor Brevis (Fig. 344) is situ- 
ated immediately behind the two preceding 
muscles. It is somewhat triangular in 
form, and arises by a narrow origin from 
the outer surface of the body and descend- 
ing ramus of the os pubis, between the 
Gracilis and Obturator externus. Its fibres 
passing backward, outward, and downward, 
are inserted, by an aponeurosis, into the 
lower part of the line leading from the lesser 
trochanter to the linea aspera and the upper 
part of the same line, immediately behind 
the Pectineus and upper part of the Ad- 
ductor longus. 
Relations.-By its anterior surface, with 
the Pectineus, Adductor longus, profunda 
femoris artery, and anterior branches of the 
obturator nerve; by its posterior surface, 
with the Adductor magnus and posterior 
branch of the obturator nerve; by its outer 
border, with the internal circumflex artery, 
the Obturator externus, and conjoined ten- 
don of the Psoas and Iliacus; by its inner 
border, with the Gracilis and Adductor 
magnus. This muscle is pierced, near its 
insertion, by the second or by the first and 
second perforating branches of the pro- 
funda femoris artery. 
The Adductor brevis should now be cut away 
near its origin, and turned outward, when the en- 
tire extent of the Adductor magnus will be exposed. 
The Adductor Magnus (Fig. 344) is a 
large triangular muscle forming a septum 
between the muscles on the inner and those 
on the back of the thigh. It arises from a 
small part of the descending ramus of the 
os pubis, from the ramus of the ischium, 
and from the outer margin of the inferior 
part of the tuberosity of the ischium. Those 
fibres which arise from the ramus of the os 
pubis are very short, horizontal in direction, 
and are inserted into the rough line leading 
from the great trochanter to the linea aspera, 
internal to the Gluteus maximus. They are 
considered by some a distinct muscle and called the Adductor minimus. The fibres 
taking origin from the ramus of the ischium are directed downward and outward 
Fig. 344. - Deep muscles of the internal femoral 
region. THE INTERNAL FEMORAL REGION 
521 
with different degrees of obliquity, to be inserted, by means of a broad aponeurosis, 
into the linea aspera and the upper part of its internal prolongation below. The 
internal portion of the muscle, consisting principally of those fibres which arise from 
the tuberosity of the ischium, forms a thick fleshy mass consisting of coarse bundles 
which descend almost vertically, and terminate about the lower third of the thigh 
in a rounded tendon, which is inserted into the Adductor tubercle on the inner 
condyle of the femur, being connected by a fibrous expansion to the line leading 
upward from the tubercle to the linea aspera. Between the two portions of the 
muscle an interval is left, tendinous in front, fleshy behind, for the passage of the 
femoral vessels from Hunter's canal into the popliteal space. The external portion 
of the muscle at its attachment to the femur presents three or four osseo-aponeurotic 
openings, formed by tendinous arches attached to the bone, from which muscular 
fibres arise. The three superior of these apertures are for the three perforating 
arteries, and the fourth, when it exists, is for the terminal branch of the profunda. 
Relations.-By its anterior surface, with the Pectineus, Adductor brevis, Ad- 
ductor longus, and the femoral and profunda vessels and obturator nerve; by its 
posterior surface, with the great sciatic nerve, the Gluteus maximus, Biceps, Semi- 
tendinosus, and Semimembranosus. By its superior or shortest border it lies 
parallel with the Quadratus femoris, the internal circumflex artery passing between 
them; by its internal or longest border, with the Gracilis, Sartorius, and fascia 
lata; by its ex ernal or attached border it is inserted into the femur behind the Ad- 
ductor brevis and Adductor longus, which separate it from the Vastus internus, 
and in front of the Gluteus maximus and short head of the Biceps, which sep- 
arate it from the Vastus externus. 
Nerves. The three Adductor muscles and the Gracilis are supplied by the 
third and fourth lumbar nerves through the obturator nerve; the Adductor mag- 
nus receiving an additional branch from the sacral plexus through the great sciatic. 
The Pectineus is supplied by the second, third, and fourth lumbar nerves through 
the anterior crural, and by the accessory obturator, from the third lumbar, when 
it exists. Occasionally it receives a branch from the obturator nerve.1 
Actions.-The Pectineus and three Adductors adduct the thigh powerfully; 
they are especially used in horse exercise, the flanks of the horse being grasped 
between the knees by the actions of these muscles. In consequence of the obliquity 
of their insertion into the linea aspera they rotate the thigh outward, assisting 
the external Rotators, and when the limb has been abducted they draw it inward, 
carrying the thigh across that of the opposite side. The Pectineus and Adductor 
brevis and longus assist the Psoas and Hiacus in flexing the thigh upon the pelvis. 
In progression, also, all these muscles assist in drawing forward the hinder limb. 
The Gracilis assists the Sartorius in flexing the leg and rotating it inward; it is 
also an adductor of the thigh. If the lower extremities are fixed, these muscles 
may take their fixed point from below and act upon the pelvis, serving to maintain 
the body in an erect posture, or, if their action is continued, to flex the pelvis 
forward upon the femur. 
Hunter's Canal {canalis adductorius\II unteri\) extends from the apex of Scarpa's 
triangle to the opening in the Adductor magnus muscle. The antero-internal 
boundary or roof of Hunter's canal is the Sartorius and the aponeurotic expan- 
sion from the Adductors to the Vastus internus. It is bounded externally by the 
Vastus internus. The Adductor longus and Magnus constitute its floor or the 
postero-internal boundary. The canal contains the femoral artery, femoral vein, 
the long saphenous nerve, and the nerve to the Vastus internus. The anterior 
opening of Hunter's canal is called the hiatus tendineus. 
1 Professor Paterson describes the Pectineus as consisting of two incompletely separated strata, of which 
the outer or dorsal stratum, which is constant, is supplied by the anterior crural nerve, or in its absence by the 
accessory obturator, with which it is intimately related; while the inner or ventral stratum, when present, is 
supplied by the obturator nerve.-Journ. of Anat, and Phys., vol. xxvi. p. 43.-Ed. of 15th English edition. 522 
THE MUSCLES AND FASCIAE 
Surgical Anatomy.-The Adductor longus is liable to be severely strained in those who ride 
much on horseback, or its tendon to be ruptured by suddenly gripping the saddle. Occasionally, 
especially in cowboys and cavalry soldiers, the tendon of insertion of the Adductor magnus 
may become ossified, constituting the rider's bone. 
THE MUSCLES AND FASCIA OF THE HIP. 
3. The Gluteal Region (Figs. 346, 347). 
Gluteus maximus. 
Gluteus medius. 
Gluteus minimus. 
Pyriformis. 
Obturator internus. 
Gemellus superior. 
Gemellus inferior. 
Quadratus femoris. 
Obturator externus. 
Dissection (Fig. 345).-The subject should be turned on its face, a block placed beneath 
the pelvis to make the buttocks tense, and the limbs allowed to hang over the end of the table, 
with the foot inverted and the thigh abducted. Make an incision through the integument along 
the crest of the ilium to the middle of the sacrum, and 
thence downward to the tip of the coccyx, and carry a 
second incision from that point obliquely downward and 
outward to the outer side of the thigh, four inches be- 
low the great trochanter. The portion of integument 
included between these incisions is to be removed in 
the direction shown in the figure. 
The Gluteus Maximus (m. glutoeus maximus) 
(Fig. 346), the most superficial muscle in the 
gluteal region, is a very broad and thick, fleshy 
mass of a quadrilateral shape, which forms the 
prominence of the buttock. Its large size is one 
of the most characteristic points in the mus- 
cular system of man, connected as it is with 
the power he has of maintaining the trunk in 
the erect posture. In structure the muscle is 
remarkably coarse, being made up of muscular 
fasciculi lying parallel with one another, and 
collected together into large bundles, separated 
by deep cellular intervals. It arises from the 
superior curved line of the ilium and the por- 
tion of bone, including the crest, immediately 
above and behind it; from the posterior sur- 
face of the lower part of the sacrum, the side of 
the coccyx, the aponeurosis of the Erector spina* 
muscle, the great sacro-sciatic ligament, and 
the fascia covering the Gluteus medius. The 
fibres are directed obliquely downward and 
outward; those forming the upper and large 
portion of the muscle, together with the super- 
ficial fibres of the lower portion, terminate in 
a thick tendinous lamina, which passes across 
the great trochanter and is inserted into the 
fascia lata covering the outer side of the thigh; 
the deeper fibres of the lower portion of the muscles are inserted into the rough 
line leading from the great trochanter to the linea aspera between the Vastus 
externus and Adductor magnus. 
1. Dissection of 
gluteal region. 
3. Back of thigh. 
2. Popliteal space. 
4. Back of leg. 
5. Sole of foot. 
Fig. 345.-Dissection of lower extremity. 
Posterior view. THE GLUTEAL REGION 
523 
Several synovial bursae are found in relation with this muscle. One of these 
(bursa trochanterica m. glutoei maximi), of large size, and generally multilocular, 
separates it from the great trochanter. A second (bursa ischiadica m. glutai 
maximi), often wanting, is situated on the tuberosity of the ischium. A third 
bursa is found between the tendon of this muscle and the Vastus externus. Two 
or three small bursae (bursce glutawfemorales) are placed between the tendon of 
the muscle and the gluteal ridge. 
Relations.-By its superficial surface, with a thin fascia, which separates it from 
the subcutaneous tissue; by its deep surface, from above downward, with the ilium, 
sacrum, coccyx, and great sacro-sciatic ligament, part of the Gluteus medius, 
Pyriformis, Gemelli, Obturator internus, Quadratus femoris, the tuberosity of 
the ischium, great trochanter, the origin of the Biceps, Semitendinosus, Semimem- 
branosus, and Adductor magnus muscles. The superficial part of the gluteal 
artery reaches the deep surface of the muscle by passing between the Pyriformis 
and the Gluteus medius; the sciatic and internal pudic vessels and nerves and 
muscular branches from the sacral plexus issue from the pelvis below the Pyri- 
formis. The first perforating artery and the terminal branches of the internal cir- 
cumflex artery are also found under cover of the muscle. Its upper border is thin, 
and connected with the Gluteus medius by the fascia lata. Its lower border is free 
and prominent. 
Dissection.-Divide the Gluteus maximus near its origin by a vertical incision carried from 
its upper to its lower border; a cellular interval will be exposed, separating it from the Gluteus 
medius and External rotator muscles beneath. The upper portion of the muscle is to be alto- 
gether detached, and the lower portion turned outward; the loose areolar tissue filling up the 
interspace between the trochanter major and tuberosity of the ischium being removed, the parts 
already enumerated as exposed by the removal of this muscle will be seen. 
The Gluteus Medius (m. glutceus medius) (Fig. 346) is a broad, thick, radiated 
muscle, situated on the outer surface of the pelvis. Its posterior third is covered by 
the Gluteus maximus; its anterior two-thirds by the fascia lata, which separates 
it from the integument. It arises from the outer surface of the ilium, between the 
superior and middle curved lines, and from the outer lip of that portion of the 
crest which is between them; it also arises from the dense fascia, the gluteal aponeu- 
rosis, covering its outer surface. The fibres converge to a strong flattened tendon 
which is inserted into the oblique line which traverses the outer surface of the 
great trochanter. A synovial bursa (bursa trochanterica m. glutoei medii anterior) 
separates the tendon of the muscle from the summit of the great trochanter. 
There is frequently a bursa (bursa trochanterica m. glutoei medii posterior) between 
the tendons of the Gluteus medius and Pyriformis. 
Relations.-By its superficial surface, with the Gluteus maximus behind, the 
Tensor fasciae femoris and deep fascia in front; by its deep surface, with the Glu- 
teus minimus and the gluteal vessels and superior gluteal nerve. Its anterior border 
is blended with the Gluteus minimus. Its posterior border lies parallel with the 
Pyriformis, the gluteal vessels intervening. 
This muscle should now be divided near its insertion and turned upward, when the Gluteus 
minimus will be exposed. 
The Gluteus Minimus (m. glutceus minimus) (Fig. 346), the smallest of the 
three Glutei, is placed immediately beneath the preceding. It is fan-shaped, 
arising from the outer surface of the ilium, between the middle and inferior 
curved lines, and behind, from the margin of the great sacro-sciatic notch; the 
fibres converge to the deep surface of a radiated aponeurosis, which, terminating 
in a tendon, is inserted into an impression on the anterior border of the great 
trochanter. 524 
THE MUSCLES AND FASCIA 
Relations.-By its superficial 
swrface,w'\\h the Gluteus medius 
and the gluteal vessels and supe- 
rior gluteal nerve; by its deep 
surface, with the ilium, the re- 
flected tendon of the Rectus 
femoris, and the capsular liga- 
ment of the hip-joint. Its ante- 
rior margin is blended with the 
Gluteus medius; its posterior 
margin is in contact and some- 
times joined with the tendon of 
the Pyriformis. There is a 
synovial bursa (bursa m. glutoei 
minimi) between the tendon of 
the Gluteus minimus and the 
great trochanter. 
The Pyriformis (m. pirifor- 
mis) (Figs. 346 and 347) is 
a flat muscle, pyramidal in 
shape, lying almost parallel 
with the posterior margin of the 
Gluteus medius. It is situated 
partly within the pelvis at its 
posterior part and partly at the 
back of the hip-joint. It arises 
from the front of the sacrum 
by three fleshy digitations at- 
tached to the portions of bone 
between the first, second, third, 
and fourth anterior sacral fora- 
mina, and also from the groove 
leading from the foramina: a 
few fibres also arise from the 
margin of the great sacro-sciatic 
foramen and from the anterior 
surface of the great sacro-sciatic 
ligament. The muscle passes 
out of the pelvis through the 
great sacro-sciatic foramen, the 
upper part of which it fills, and 
is inserted by a rounded tendon 
into the upper border of the 
great trochanter, behind, but 
often partly blended with, the 
tendon of the Obturator in- 
terims and Gemelli muscles. 
Relations. - By its anterior 
surface, within the pelvis, with 
the Rectum (especially on the 
left side), the sacral plexus of 
nerves, and the branches of the 
internal iliac vessels; external 
to the pelvis, with the posterior 
Inner hamstring 
tendons. 
Outer 
hamstring 
tendon. 
SARTORIUS. 
GRACILIS. 
BICEPS. 
SEMITENDINOSUS 
SEMIMEMBRA- 
NOSUS. 
Fig. 346.-Muscles of the hip and thigh. THE GLUTEAL REGION 
525 
surface of the ischium and the capsular ligament of the hip-joint; by its posterior 
surface, within the pelvis, with the sacrum, and external to it, with the Gluteus 
maximus; by its upper border, with the Gluteus medius, from which it is 
separated by the gluteal vessels and superior gluteal nerve; by its lower border, 
with the Gemellus superior and Coccygeus, the sciatic vessels and nerves, the 
internal pudic vessels and nerve, and muscular branches from the sacral plexus, 
passing from the pelvis in the interval between the two muscles. There is 
usually a bursa (bursa m. piriformis} between the tendon of the pyriformis and 
the ilium. 
The Obturator Membrane (membrana obturatoria} (Fig. 215) is a thin layer of 
interlacing fibres which closes almost completely the obturator foramen. It is 
attached, externally, to the margin of the foramen; internally, to the posterior 
surface of the ischio-pubic ramus, below and internal to the margin of the 
foramen. It presents at its upper and outer part a small canal, obturator canal 
(canalis obturatorius} for the passage of the obturator vessels and nerve. Both 
obturator muscles are connected with this membrane. 
Dissection.-The next muscle, as well as the origin of the Pyriformis, can only be seen when 
the pelvis is divided and the viscera removed. 
The Obturator Internus(Figs. 34G and 347), like the preceding muscle, is situated 
partly within the cavity of the pelvis, and partly at the back of the hip-joint. It arises 
from the inner surface of the anterior and external wall of the pelvis, where it sur- 
rounds the greater part of the obturator foramen, being attached to the descending 
ramus of the os pubis and the ramus of the ischium, and at the side to the inner sur- 
face of the innominate bone below and behind the pelvic brim, reaching from the 
upper part of the great sacro-sciatic foramen above and behind to the thyroid 
foramen below and in front. It also arises from the inner surface of the obturator 
membrane except at its posterior part, from the tendinous arch which completes 
the canal for the passage of the obturator vessels and nerve and to a slight extent 
from the obturator layer of the pelvic fascia, which covers it. The fibres converge 
rapidly, and are directed backward and downward, and terminate in four or five 
tendinous bands, which are found on its deep surface; these bands are reflected at 
a right angle over the inner surface of the tuberosity of the ischium, which is 
grooved for their reception; the groove is covered with cartilage, and lined by a 
synovial bursa (bursa m. obturatoris interni). The muscle leaves the pelvis by 
the lesser sacro-sciatic foramen; and the tendinous bands unite into a single flat- 
tened tendon, which passes horizontally outward, and, after receiving the attach- 
ment of the Geinelli, is inserted into the forepart of the inner surface of the great 
trochanter in front of the Obturator externus. A synovial bursa, narrow and 
elongated in form, is usually found between the tendon of this muscle and the 
capsular ligament of the hip: it occasionally communicates with the bursa 
between the tendon and the tuberosity of the ischium, the two forming a 
single sac. 
In order to display the peculiar appearances presented by the tendon of this muscle, it must 
be divided near its insertion and reflected inward. 
Relations.-Within the pelvis this muscle is in relation, by its anterior surface, 
with the obturator membrane and inner surface of the anterior wall of the pelvis; 
by its posterior surface, with the pelvic and obturator fasciae, which separate it 
from the Levator ani; and it is crossed by the internal pudic vessels and nerve. 
This surface forms the outer boundary of the ischio-rectal fossa (Fig. 339). 
External to the pelvis it is covered by the Gluteus maximus, is crossed by the 
great sciatic nerve, and rests on the back part of the hip-joint. As the tendon 
of the Obturator internus emerges from the lesser sacro-sciatic foramen it is over- THE MUSCLES AND FASCIAE 
526 
lapped by the two Gemelli, while nearer its insertion the Gemelli pass in front of it 
and form a groove in which the tendon lies. 
The Gemelli (Fig. 346) are two small muscular fasciculi, accessories to the 
tendon of the Obturator internus, which is received into a groove between them. 
They are called superior and inferior. 
The Gemellus Superior, the smaller of the two, arises from the outer surface 
of the spine of the ischium, and, passing horizontally outward, becomes blended 
SACRO-SPINAL 
LIGAMENT WITH 
COCCYGEUS 
MUSCLE 
GREATER 
TROCHANTER 
INTERTROCHANTERIC 
LINE 
TUBEROSITY^ 
OF ISCHIUM 
LESSER 
TROCHANTER 
Fig. 347.-Muscles of the small or true pelvis on the right side, viewed from without and below. (Spalteholz.) 
with the upper part of the tendon of the Obturator internus, and is inserted with 
it into the inner surface of the great trochanter. This muscle is sometimes wanting. 
Relations.-By its superficial surface, with the Gluteus maximus and the sciatic 
vessels and nerves; by its deep surface, with the capsule of the hip-joint; by its THE GLUTEAL REGION 
527 
upper border, with the lower margin of the Pyriformis; by its lower border, with 
the tendon of the Obturator internus. 
The Gemellus Inferior arises from the upper part of the tuberosity of the ischium, 
where it forms the lower edge of the groove for the Obturator internus tendon, 
and, passing horizontally outward, is blended with the lower part of the tendon 
of the Obturator internus, and is inserted with it into the inner surface of the great 
trochanter. 
Relations.-By its superficial surface, with the Gluteus maximus and the sciatic 
vessels and nerves; by its deep surface, with the scapular ligament of the hip-joint; 
by its upper border, with the tendon of the Obturator internus; by its lower border, 
with the tendon of the Obturator externus and Quadratus femoris. 
The Quadratus Femoris (I ig. 346) is a short, flat muscle, quadrilateral in shape 
(hence its name), situated between the Gemellus inferior and the upper margin 
of the Adductor magnus. It arises from the upper part of the external lip of the 
tuberosity of the ischium, and, proceeding horizontally outward, is inserted into 
the upper part of the linea quadrata; that is, the line which crosses the posterior 
intertrochanteric line. A synovial bursa is often found between the under surface 
of this muscle and the lesser trochanter, which it covers. 
Obturator 
artery. 
Anterior division of 
obturator nerve. 
Anterior inferior 
iliac spine. 
Capsular liga- 
ment partly 
cut away. 
Posterior division 
of obturator 
nerve. 
Internal circum- 
flex artery. 
Fig. 348.-Obturator externus muscle. (From a preparation in the Museum of the Royal College of 
Surgeons of England.) 
Relations.-By its posterior surface, with the Gluteus maximus and the sciatic 
vessels and nerves; by its anterior surface, with the tendon of the Obturator exter- 
nus and trochanter minor and with the capsule of the hip-joint; by its upper 
border, with the Gemellus inferior. Its lower border is separated from the Adductor 
magnus by the terminal branches of the internal circumflex vessels. 
Dissection.-In order to expose the next muscle (the Obturator externus) it is necessary 
to remove the Psoas, Iliacus, Pectineus, and Adductor brevis and longus muscles from the front 528 
THE MUSCLES AND FASCIAE 
and inner side of the thigh, and the Gluteus maximus and Quadratus femoris from the back 
part. Its dissection should, consequently, be postponed until the muscles of the anterior and 
internal femoral regions have been explained. 
The Obturator Externus (Figs. 347 and 348) is a flat, triangular muscle, which 
covers the outer surface of the anterior wall of the pelvis. It arises from the margin 
of bone immediately around the inner side of the obturator foramen-viz., from the 
body and ramus of the os pubis and the ramus of the ischium; it also arises from 
the inner two-thirds of the outer surface of the obturator membrane, and from 
the tendinous arch which completes the canal for the passage of the obturator 
vessels and nerves. The fibres from the pubic arch extend on to the inner sur- 
face of the bone, from which they obtain a narrow origin between the margin of 
the foramen and the attachment of the membrane. The fibres converging 
pass backward, outward, and upward, and terminate in a tendon which runs 
across the back part of the hip-joint, and is inserted into the digital fossa of the 
femur. 
Relations.--By its anterior surface, with the Psoas, Iliacus, Pectineus, Adductor 
magnus, and Adductor brevis; and more externally, with the neck of the femur 
and capsule of the hip-joint. The obturator artery and vein lie between this 
muscle and the obturator membrane; the superficial part of the obturator nerve 
lies above the muscle, and the deep branch perforates it; by its posterior surface, 
with the obturator membrane and Quadratus femoris. 
Nerves.-The Gluteus maximus is supplied by the fifth lumbar and first and 
second sacral nerves through the inferior gluteal nerve from the sacral plexus; 
the Gluteus medius and minimus, by the fourth and fifth lumbar and first sacral 
nerves through the superior gluteal; the Pyrifonnis is supplied by the first and 
second sacral nerves; the Gemellus inferior and Quadratus femoris by the last 
lumbar and first sacral nerve; the Gemellus superior and Obturator internus by 
the fifth lumbar and first and second sacral nerves, and the Obturator externus 
by the second, third, and fourth lumbar nerves through the obturator. 
Actions.-The Gluteus maximus, when it takes its fixed point from the pelvis, 
extends the femur and brings the bent thigh into a line with the body. Taking 
its fixed point from below, it acts upon the pelvis, supporting it and the whole 
trunk upon the head of the femur, which is especially obvious in standing on one 
leg. Its most powerfid actions are to hold the head of the femur in close approxi- 
mation to the acetabulum in walking and to cause the body to regain the erect 
position after stooping by drawing the pelvis backward, being assisted in this action 
by the Biceps, Semitendinosus, and Semimembranosus. The Gluteus maximus 
is a tensor of the fascia lata, and by its connection with the ilio-tibial band it steadies 
the femur on the articular surface of the tibia during standing, when the Extensor 
muscles are relaxed. The lower part of the muscle also acts as an adductor and 
external rotator of the limb. The Gluteus medius and minimus abduct the thigh 
when the limb is extended, and are principally called into action in supporting 
the body on one limb, in conjunction with the Tensor fasciie femoris. Their 
anterior fibres, by drawing the great trochanter forward, rotate the thigh inward, 
in which action they are also assisted by the Tensor fasciae femoris. The remain- 
ing muscles are powerful rotators of the thigh outward. In the sitting posture, 
when the thigh is flexed upon the pelvis, their action as rotators cease, and they 
become abductors, with the exception of the Obturator externus, which still 
rotates the femur outward. When the femur is fixed, the Pyriformis and Obturator 
muscles serve to draw the pelvis forward if it has been inclined backward, and 
assist in steadying it upon the head of the femur. 
Surgical Anatomy.-The fascia over the gluteal region is extremely dense and an abscess 
beneath it may pass far down into the thigh. THE POSTERIOR FEMORAL REGION 
529 
4. The Posterior Femoral Region. 
Biceps. 
Semitendinosus. 
(Hamstring muscles.) 
Semimembranosus. 
Dissection (Fig. 345).-Make a vertical incision along the middle of the back of the thigh, 
from the lower fold of the buttock to about three inches below the back of the knee-joint, and 
there connect it with a transverse incision, carried from the inner to the outer side of the leg. 
Make a third incision transversely at the junction of the middle with the lower third of the 
thigh. The integument having been removed from the back of the knee, and the boundaries 
of the popliteal space having been examined, the removal of the integument from the remaining 
part of the thigh should be continued, when the fascia and muscles of this region will be exposed. 
GASTROCNEMIUS 
(inner head) 
BURSA OF INNER 
HEAD OF 
GASTROCNEMIUS 
BURSA OF 
SEMIMEMBRANOSUS" 
BURSA OF 
APONEUROTIC 
EXPANSION" 
OF SARTORIUS 
DEEP FASCIA 
OF LEG 
Fig. 349.-Region of the knee, seen obliquely from behind and within. Right limb. (Toldt.) 
The Biceps or Biceps Flexor Cruris (m. biceps femoris) is a large muscle, of 
considerable length, situated on the posterior and outer aspect of the thigh 
(Figs. 346 and 349). It arisesby two heads. One, the long head (caput longum), 
arises from the lower and inner impression on the back part of the tuberosity 530 
THE MUSCLES AND EASCEE 
of the ischium, by a tendon common to it and the Semitendinosus, and from 
the lower part of the great sacro-sciatic ligament. Between this tendon of 
origin and the Semimembranosus there is often a bursa (bursa m. bicipitis 
fernoris superior). The femoral, or short head (caput breve), arises from the 
outer lip of the linea aspera, between the Adductor magnus and Vastus externus, 
extending up almost as high as the insertion of the Gluteus maximus; from 
the outer prolongation of the linea aspera to within two inches of the outer con- 
dyle, and from the external intermuscular septum. The fibres of the long head 
form a fusiform belly, which, passing obliquely downward and a little out- 
ward, terminates in an aponeurosis which covers the posterior surface of the 
muscle, and receives the fibres of the short head: this aponeurosis becomes 
gradually contracted into a tendon, which is inserted into the outer side of the 
head of the fibula, and by a small slip into the lateral surface of the external 
tuberosity of the tibia. At its insertion the tendon divides into two portions, which 
embrace the long external lateral ligament of the knee-joint. From the posterior 
border of the tendon a thin expansion is given off to the fascia of the leg. The 
tendon of this muscle forms the outer hamstring. Sometimes there is a bursa 
(bursa bicipifogastrocnemialis) between the tendon of insertion of the Biceps and 
the origin of the Gastrocnemius, and there is a bursa (bursa m. bicipitis femoris 
inferior) between the tendon of the biceps and the external lateral ligament. 
Relations.-By its superficial surface, with the Gluteus maximus and the small 
sciatic nerve, the fascia lata, and integument. By its deep surface, with the Semi- 
membranosus, Adductor magnus, and Vastus externus, the great sciatic nerve, 
and, near its insertion, with the external head of the Gastrocnemius, the Plantaris, 
the superior external articular artery, and the external popliteal nerve. 
The Semitendinosus (Figs. 346 and 349), remarkable for the great length 
of its tendon, is situated at the posterior and inner aspect of the thigh. It 
arises from the lower and inner impression on the tuberosity of the ischium 
by a tendon common to it and the long head of the Biceps; it also arises from 
an aponeurosis which connects the adjacent surfaces of the two muscles to 
the extent of about three inches after their origin. There is a bursa (bursa 
m. bicipitis femoris superior) between the tendons of origin of the Biceps and 
Semitendinosus on one side and the tendon of origin of the Semimembranosus 
on the other. The Semitendinosus is a fusiform muscle, which, passing down- 
ward and inward, terminates a little below the middle of the thigh in a long 
round tendon which lies along the inner side of the popliteal space, then 
curves around the inner tuberosity of the tibia, and is inserted into the upper 
part of the inner surface of the shaft of that bone nearly as far forward as its 
anterior border. At its insertion it gives off from its lower border a prolongation 
to the deep fascia of the leg. This tendon lies behind the tendon of the Sar- 
torius, and below that of the Gracilis, to which it is united. A tendinous inter- 
section is usually observed about the middle of the muscles. The bursa anserina 
lies between the tendon of the Semitendinosus and the tibia. This bursa was 
referred to in speaking of the Gracilis, p. 519. 
Relations.-By its superficial surface, with the Gluteus maximus and fascia lata; 
by its deep surface, with the Semimembranosus, Adductor magnus, inner head of 
the Gastrocnemius, and internal lateral ligament of the knee-joint. 
The Semimembranosus (Figs. 346 and 349), so called from its membranous 
tendon of origin, is situated at the back part and inner side of the thigh. It 
arises by a thick tendon from the upper and outer impression on the back part 
of the tuberosity of the ischium, above and to the outer side of the Biceps and 
Semitendinosus, and is inserted into the groove on the inner and back part of the 
inner tuberosity of the tibia, beneath the internal lateral ligament. The tendon of 
the muscle at its origin expands into an aponeurosis which covers the upper part THE ANTERIOR TIBIO-FIBULAR REGION 
531 
of its anterior surface: from this aponeurosis muscular fibres arise, and converge 
to another aponeurosis, which covers the lower part of its posterior surface and 
contracts into the tendon of insertion. The tendon of the muscle at its insertion 
gives off certain fibrous expansions; one of these, of considerable size, passes 
upward and outward to be inserted into the back part of the outer condyle of 
the femur, forming part of the posterior ligament of the knee-joint; a second is 
continued downward to the fascia which covers the Popliteus muscle. The 
tendon also sends a few fibres to join the internal lateral ligament of the joint. 
The tendons of the two preceding muscles, with that of the Gracilis, form 
the inner hamstrings. 
Relations.-By its superficial surface, with the Gluteus maximus, Semitendinosus, 
Biceps, and fascia lata; by its deep surface, with the origin of the Quadratus 
femoris, popliteal vessels, Adductor magnus, and inner head of the Gastroc- 
nemius; by its inner border, with the Gracilis; by its outer border, with the great 
sciatic nerve, and its internal popliteal branch. There is a bursa between the 
Gastrocnemius and Semimembranosus and another bursa between the Semi- 
membranosus and the inner condyle of the tibia. The first bursa usually com- 
municates with the knee-joint. These two bursae are in communication and in 
reality constitute a double bursa (bursa m. semimembranosi). 
Nerves.-The muscles of this region are supplied by the first, second, and 
third sacral nerves through the great sciatic nerve. 
Actions.-'Idle hamstring muscles flex the leg upon the thigh. When the knee 
is semiflexed, the Biceps, in consequence of its oblique direction downward and 
outward, rotates the leg slightly outward; and the Semitendinosus, and to a 
slight extent the Semimembranosus, rotate the leg inward, assisting the Popliteus. 
Taking their fixed point from below, these muscles, especially the Semimem- 
branosus, serve to support the pelvis upon the head of the femur and to draw 
the trunk directly backward, as in raising it from the stooping position or in 
feats of strength, when the body is thrown backward in the form of an arch. 
When the leg is extended on the thigh, they limit the amount of flexion of the 
trunk on the lower limbs. 
Surgical Anatomy.-The hamstring tendons are occasionally ruptured. In disease of the 
knee-joint the hamstrings may contract, flexing the knee, drawing the tibia backward, and some- 
times causing incomplete dislocation. The tendons of these muscles occasionally require sub- 
cutaneous division in some forms of spurious ankylosis of the knee-joint dependent upon 
permanent contraction and rigidity of the Flexor muscles, or from stiffening of the ligamentous 
and other tissues surrounding the joint, the result of disease. • Division of a tendon is effected 
by putting the tendon upon the stretch, and inserting a narrow sharp-pointed knife between 
it and the skin: the cutting edge being then turned toward the tendon, it should be divided, 
taking great care that the wound in the skin is not at the same time enlarged. The relation of the 
external popliteal nerve to the tendon of the Biceps must always be borne in mind in dividing this 
tendon. 
These may be divided into three groups: those on the anterior, those on the 
posterior, and those on the outer side of the leg. 
III. MUSCLES AND FASCIA OF THE LEG. 
5. The Anterior Tibio-fibular Region (Fig. 350). 
Tibialis anticus. Extensor longus digitorum. 
Extensor proprius hallucis.1 Peroneus tertius. 
1 There is no such word as "Hallux, -cis." It is the result of some ignorant blunder, copied until it has become 
established by usage; it has been thought better, therefore, to retain it. According to Lewis and Short, the 
word is Allex, masculine; genitive, Allicis, the great toe, and the correct rendering would be Extensor pro- 
prius allicis. It is a rare word, and is sometimes spelt, but not so correctly, "Hallex." It is used by Plautus, 
in the "Poenulus," V.,v. 31, of a little man, as we might say "a hop-o'-my-thumb." "Tunc hie amator audes 
esse, allex viri" (To think of you daring to make up to her, you hop-o'-my-thumb!). The word "alex," some- 
times spelt "allex," a fish sauce, is probably a different word altogether. It is used by Horace and Pliny. 
-Ed. of 15th English edition. 532 
THE MUSCLES AND EASCIxE 
Dissection (Fig. 341).-The knee should be bent, a block placed beneath it, and the foot 
kept in an extended position; then make an incision through the integument in the middle line 
of the leg to the ankle, and continue it along the dorsum of the foot to the toes. Make a second 
incision transversely across the ankle, and a third in the same direction across the bases of the 
toes; remove the flaps of integument included between these incisions in order to examine the 
deep fascia of the leg. 
The Deep Fascia of the Leg (fascia cruris) forms a complete investment to 
the muscles, but is not continuous over the subcutaneous surfaces of the bones. 
It is continuous above with the fascia lata, receiving an expansion from the tendon 
of the Biceps on the outer side, and from the tendons of the Sartorius, Gracilis, 
and Semitendinosus on the inner side; in front it blends with the periosteum 
covering the subcutaneous surface of the tibia, and with that covering the head 
and external malleolus of the fibula; below it is continuous with the annular liga- 
ments of the ankle. It is thick and dense in the upper and anterior part of the leg, 
and gives attachment, by its deep surface, to the Tibialis anticus and Extensor 
longus digitorum muscles, but is thinner behind, where it covers the Gastrocnemius 
and Soleus muscles. Over the popliteal space it is much strengthened by trans- 
verse fibres which stretch across from the inner to the outer hamstring muscles, 
and it is here perforated by the external saphenous vein. Its deep surface gives 
off, on the outer side of the leg, two strong intermuscular septa which enclose the 
Peronei muscles, and separate them from the muscles of the anterior and posterior 
tibial regions. It also gives off several smaller and more slender processes 
which enclose the individual muscles in each region; at the same time a broad 
transverse intermuscular septum, called the deep transverse fascia of the leg, 
intervenes between the superficial and deep muscles in the posterior tibio-fibular 
region. 
Remove the fascia by dividing it in the same direction as the integument, excepting opposite 
the ankle, where it should be left entire. Commence the removal of the fascia from below, 
opposite the tendons, and detach it in the line of direction of the muscular fibres. 
The Tibialis Anticus (hi. tibialis anterior) is situated on the outer side of the 
tibia; it is thick and fleshy at its upper part, tendinous below. It arises from the 
outer tuberosity and upper two-thirds of the external surface of the shaft of the 
tibia; from the adjoining part of the interosseous membrane; from the deep 
surface of the fascia; and from the intermuscular septum between it and the 
Extensor longus digitorum: the fibres pass vertically downward, and terminate 
in a tendon which is apparent on the anterior surface of the muscle at the lower 
third of the leg. After passing through the innermost compartment of the anterior 
annular ligament, it is inserted into the inner and under surface of the internal 
cuneiform bone and base of the metatarsal bone of the great toe. There is 
usually a bursa (bursa subtendinea m. tibialis anterioris) between the tendon of 
the tibialis anticus and the internal cuneiform bone. 
Relations.-By its anterior surface, with the fascia and with the annular liga- 
ment; by its posterior surjace, with the interosseous membrane, tibia, ankle-joint, 
and inner side of the tarsus: this surface also overlaps the anterior tibial vessels 
and nerve in the upper part of the leg. By its inner surface, with the tibia; by 
its outer surface, with the Extensor longus digitorum and Extensor proprius 
hallucis, and the anterior tibial vessels and nerve. 
The Extensor Proprius Hallucis (m. extensor hallucis longus) is a thin, elon- 
gated, and flattened muscle situated between the Tibialis anticus and Extensor 
longus digitorum. It arises from the anterior surface of the fibula for about the 
middle two-fourths of its extent, its origin being internal to that of the Extensor 
longus digitorum; it also arises from the interosseous membrane to a similar 
extent. The fibres pass downward, and terminate in a tendon which occupies THE ANTERIOR TIBIO-FIBULAR REGION 
533 
the anterior border of the muscle, passes through a 
distinct compartment in the lower portion of the 
annular ligament, crosses the anterior tibial vessels 
near the bend of the ankle, and is inserted into the 
base of the last phalanx of the great toe. Opposite 
the metatarso-phalangeal articulation the tendon 
gives off a thin prolongation on each side, which 
covers the surface of the joint. It usually sends an 
expansion from the inner side of the tendon, to be 
inserted into the base of the first phalanx. 
Relations.-By its anterior surjace, with the fascia 
and the anterior annular ligament; by its posterior 
surjace, with the interosseous membrane, fibula, 
tibia, and ankle-joint; by its outer side, with the 
Extensor longus digitorum above, the dorsalis pedis 
vessels, anterior tibial nerve, and Extensor brevis 
digitorum below; by its inner side, with the Tibialis 
anticus and the anterior tibial vessels above. The 
muscle is external to the anterior tibial vessels in 
the upper part of the leg; but in the lower third its 
tendon crosses over them, so that it lies internal to 
them on the dorsum of the foot. 
The Extensor Longus Digitorum (m. extensor 
digitorum longus) is an elongated, flattened, penni- 
form muscle situated the most externally of all the 
muscles on the forepart of the leg. It arises from 
the outer tuberosity of the tibia; from the upper 
three-fourths of the anterior surface of the shaft of 
the fibula; from the interosseous membrane; from 
the deep surface of the fascia; and from the inter- 
muscular septa between it and the Tibialis anticus 
on the inner and the Peronei on the outer side. 
The tendon enters a canal in the annular ligament 
with the Peroneus tertius, and divides into four 
slips, which run across the dorsum of the foot and 
are inserted into the second and third phalanges of 
the four lesser toes. The mode in which the tendons 
are inserted is the following: Each of the three 
inner tendons opposite the metatarso-phalangeal 
articulation is joined, on its outer side, by a ten- 
don from the Extensor brevis digitorum. The outer 
tendon does not receive such a tendinous slip. They 
all receive a fibrous expansion from the Interossei 
and Lumbricales, and then spread out into a broad 
aponeurosis, which covers the dorsal surface of the 
first phalanx: this aponeurosis, at the articulation of 
the first with the second phalanx, divides into three 
slips-a middle one, which is inserted into the base 
of the second phalanx, and two lateral slips, which, 
after uniting on the dorsal surface of the second 
phalanx, are continued onward, to be inserted into 
the base of the third. 
Relations.-By its anterior surjace, with the fascia 
and the annular ligament; by its posterior surjace, 
Fig. 350.-Muscles of the front of 
the leg. THE MUSCLES AND FASCIAE 
534 
with the fibula, interosseous membrane, ankle-joint, and Extensor brevis digi- 
torum; by its inner side, with the Tibialis anticus, Extensor proprius hallucis, 
and anterior tibial vessels and nerve; by its outer side, with the Peroneus longus 
and brevis. 
The Peroneus Tertius (m. peronceus tertius) is a part of the Extensor longus 
digitorum, and might be described as its fifth tendon. The fibres belonging to 
this tendon arise from the lower fourth of the anterior surface of the fibula, from 
the lower part of the interosseous membrane, and from an intermuscular septum 
between it and the Peroneus brevis. The tendon, after passing through the same 
canal in the annular ligament as the Extensor longus digitorum, is inserted into 
the dorsal surface of the base of the metatarsal bone of the little toe. This 
muscle is sometimes wanting. 
Nerves.-These muscles are supplied by the fourth and fifth lumbar and first 
sacral nerves through the anterior tibial nerve. 
Actions.-The Tibialis anticus and Peroneus tertius are the direct flexors of the 
foot at the ankle-joint; the former muscle, when acting in conjunction with the 
Tibialis posticus, raises the inner border of the foot (i.e., inverts the foot); and 
the latter, acting with the Peroneus brevis and longus, draws the outer border of 
the foot upward and the sole outward (i. e., everts the foot). The Extensor longus 
digitorum and Extensor proprius hallucis extend the phalanges of the toes, and, 
continuing their action, flex the foot upon the leg. Taking their fixed point from 
below, in the erect posture, all these muscles serve to fix the bones of the leg in the 
perpendicular position, and give increased strength to the ankle-joint. 
6. The Posterior Tibio-fibular Region (Figs. 349, 352). 
Dissection (Fig. 345).-Make a vertical incision along the middle line of the back of the 
leg, from the lower part of the popliteal space to the heel, connecting it below by a transverse 
incision extending between the two malleoli; the flaps of integument being removed, the fascia 
and muscles should be examined. 
The muscles in this region of the leg are subdivided into two layers-superficial 
and deep. The superficial layer constitutes a powerful muscular mass, forming 
the calf of the leg. Their large size is one of the most characteristic features of 
the muscular apparatus in man, and bears a direct connection with his ordinary 
attitude and mode of progression. 
The Superficial Layer. 
Gastrocnemius 
Soleus. 
Plantaris. 
The Gastrocnemius is the most superficial muscle, and forms the greater part 
of the calf. It arises by two heads, which are connected to the condyles of the femur 
by two strong flat tendons. The inner and larger head (caput mediate) arises from 
a depression at the upper and back part of the inner condyle and from the 
adjacent part of the femur. There is a bursa (bursa m. gastrocnemii medialis) 
between the tendon of origin and the inner condyle. The outer head (caput 
laterals) arises from an impression on the outer side of the external condyle and 
from the posterior surface of the femur immediately above the condyle. There 
is a bursa (bursa m. gasfrocnemii lateralis) between the tendon of origin and the 
outer condyle. Both heads, also, arise by a few tendinous and fleshy fibres 
from the ridges which are continued upward from the condyles to the linea aspera. 
Each tendon spreads out into an aponeurosis, which covers the posterior surface 
of that portion of the muscle to which it belongs; the muscular fibres of the 
inner head being thicker and extending lower than those of the outer. From 
the anterior surface of these tendinous expansions muscular fibres are given off. THE POSTERIOR TIBIO-FIBULAR REGION 
535 
The fibres in the median line, which correspond to the accessory portions of the 
muscle derived from the bifurcations of the linea aspera, unite at an angle 
upon a median tendinous raphe below: the remaining fibres converge to an 
aponeurosis which covers the anterior surface of the muscle, and this, gradually 
contracting, unites with the tendon of the Soleus, and forms with it the tendo 
Achillis. 
Relations.-By its superficial surface, with the fascia of the leg, which separates 
it from the external saphenous vein and nerve; by its deep surface, with the pos- 
terior ligament of the knee-joint, the Popliteus, Soleus, Plantaris, popliteal vessels, 
and internal popliteal nerve. The tendon of the inner head corresponds with the 
back part of the inner condyle, from which it is separated by a synovial bursa, 
which, in some cases, communicates with the cavity of the knee-joint. The 
tendon of the outer head contains a sesamoid fibro-cartilage (rarely osseous) 
where it plays over the corresponding outer condyle; and one is occasionally 
found in the tendon of the inner head. 
The Gastrocnemius should he divided across, just below its origin, and turned downward, 
in order to expose the next two muscles. 
The Soleus is a broad flat muscle situated immediately beneath the Gastroc- 
nemius. It has received its name from its resemblance in shape to a sole-fish. It 
arises by tendinous fibres from the back part of the head of the fibula and from 
the upper third of the posterior surface of its shaft; 
from the oblique line of the tibia and from the mid- 
dle third of its internal border; some fibres also arise 
from a tendinous arch placed between the tibial and 
fibular origins of the muscle, beneath which the 
popliteal vessels and internal popliteal nerve pass. 
The fibres pass backward to an aponeurosis which 
covers the posterior surface of the muscle, and this, 
gradually becoming thicker and narrower, joins with 
the tendon of the Gastrocnemius, and forms with it 
the tendo Achillis. 
The triceps sura? is the designation in the new 
nomenclature of the Gastrocnemius and Soleus. 
Relations. - By its superficial surface, with the 
Gastrocnemius and Plantaris; by its deep surface, 
with the Flexor longus digitorum, Flexor longus 
hallucis, Tibialis posticus, and posterior tibial 
vessels and nerve, from which it is separated by 
the transverse intermuscular septum or deep transverse fascia of the leg. 
The Tendo Achillis (tendo calcaneus), the common tendon of the Gastrocnemius 
and Soleus,1 is the thickest and strongest tendon in the body. It is about six 
inches in length, and commences about the middle of the leg, but receives fleshy 
fibres on its anterior surface nearly to its lower end. Gradually becoming con- 
tracted below, it is inserted into the lower part of the posterior surface of the os 
calcis, a synovial bursa, the retro-calcaneal bursa (bursa tendinis calcanei 
[Achillis]} (Fig. 351), being interposed between the tendon and the upper part 
of this surface. The tendon spreads out somewhat at its lower end, so that its 
narrowest part is usually about an inch and a half above its insertion. The tendon 
is covered by the fascia and the integument, a bursa (bursa subcutanea calcanea) 
(big. 351) being often interposed between the tendon and the fascia. The tendon 
BURSA BETWEEN 
FASCIA AND 
TENDON 
BURSA BETWEEN 
TENDON AND 
OS CALCIS 
Fig. 351. - Bursae of the tendo 
Achillis. (Poirier and Charpy.) 
1 These two muscles with a common tendon are by some anatomists classed together as one muscle, the- 
Trirtps surx, the two heads of origin of the Gastrocnemius and the Soleus constituting the three heads of the 
Triceps, and the tendo Achillis the single tendon of insertion.-Ed. of 15th English edition. 536 
THE MUSCLES AND FASCIAE 
is separated from the deep muscles and vessels by a considerable interval filled 
up with areolar and adipose tissue. Along its outer side, but superficial to it, is 
the external saphenous vein. 
1- Tendons of 
PERONEUS LONGUS 
; and BREVIS. 
Fig. 352.-Muscles of the back of the leg. 
Superficial layer. 
Fig. 353.-Muscles of the back 
of the leg. Deep layer. 
The Plantaris is an extremely diminutive muscle placed between the Gas- 
trocnemius and Soleus, and remarkable for its long and delicate tendon. It arises THE POSTERIOR TIBIO-FIBULAR REGION 
537 
from the lower part of the outer prolongation of the linea aspera and from the pos- 
terior ligament of the knee-joint. It forms a small fusiform belly, about three or 
four inches in length, terminating in a long slender tendon which crosses obliquely 
between the two muscles of the calf, and, running along the inner border of the 
tendo Achillis, is inserted with it into the posterior part of the os calcis. This 
muscle is occasionally double, and is sometimes wanting. Occasionally its tendon 
is lost in the internal annular ligament or in the fascia of the leg. 
Nerves.-The Gastrocnemius is supplied by the first and second sacral nerves, 
and the Plantaris by the fourth and fifth lumbar and first sacral nerves through the 
internal popliteal. The Soleus is supplied by the fifth lumbar and first and second 
sacral nerves through the internal popliteal and posterior tibial. 
Actions.-The muscles of the calf are the chief extensors of the foot at the 
ankle-joint. They possess considerable power, and are constantly called into use 
in standing, walking, dancing, and leaping; hence the large size they usually pre- 
sent. In walking these muscles draw powerfully upon the os calcis, raising the 
heel, and with it the entire body, from the ground; the body being thus supported 
on the raised foot, the opposite limb can be carried forward. In standing, the 
Soleus, taking its fixed point from below, steadies the leg upon the foot, and pre- 
vents the body from falling forward, to which there is a constant tendency from the 
superincumbent weight. The Gastrocnemius, acting from below, serves to flex the 
femur upon the tibia, assisted by the Popliteus. The Plantaris is the rudiment of 
a large muscle which exists in some of the lower animals and is continued over the 
os calcis to be inserted into the plantar fascia. In man it is an accessory to the 
Gastrocnemius, extending the ankle if the foot is free, or bending the knee if the 
foot is fixed. Possibly, acting from below, by its attachment to the posterior liga- 
ment of the knee-joint, it may pull that ligament backward during flexion, and so 
protect it from being compressed between the two articular surfaces. 
The Deep Layer (Fig. 353). 
Popliteus. 
Flexor longus hallucis. 
Flexor longus digitorum. 
Tibialis posticus. 
Dissection.-Detach the Soleus from its attachment to the fibula and tibia, and turn it down- 
ward, when the deep layer of muscles is exposed, covered by the deep transverse fascia of the 
leg- 
Deep Transverse Fascia.-The deep transverse fascia of the leg is a trans- 
versely placed, intermuscular septum, between the superficial and deep muscles 
in the posterior tibio-fibular region. On either side it is connected to the margins 
of the tibia and fibula. Above, where it covers the Popliteus, it is thick and dense, 
and receives an expansion from the tendon of the Semimembranosus; it is thinner 
in the middle of the leg, but below, where it covers the tendons passing behind the 
malleoli, it is thickened and continuous with the internal annular ligament. 
This fascia should now be removed, commencing from below opposite the tendons, and 
detaching it from the muscles in the direction of their fibres. 
The PopliteilS (Fig. 349) is a thin, flat, triangular muscle, which forms part of 
the floor of the popliteal space. It arises by a strong tendon, about an inch in 
length, from a deep depression on the outer side of the external condyle of the 
femur, and from the posterior ligament of the knee-joint. A bursa (bursa m. 
poplitei) is placed between the condyle and the muscle. The muscle is inserted 
into the inner two-thirds of the triangular surface above the oblique line on the 
posterior surface of the shaft of the tibia, and into the tendinous expansion 
covering the surface of the muscle. The tendon of the muscle is covered by 
that of the Biceps and by the external lateral ligament of the knee-joint; it grooves THE MUSCLES AND FASCIAE 
538 
the posterior border of the external semilunar fibro-cartilage, and is invested by 
the synovial membrane of the knee-joint. 
Relations.-By its superficial surface, with the fascia covering it, which separates 
it from the Gastrocnemius, Plantaris, popliteal vessels, and internal popliteal nerve; 
by its deep surface, with the knee-joint and back of the tibia. 
The Flexor Longus Hallucis (m. flexor hallucis longus) is situated on the fibular 
side of the leg, and is the most superficial and largest of the three next muscles. 
It arises from the lower two-thirds of the posterior surface of the shaft of the 
fibula, with the exception of an inch at its lowest part; from the lower part of 
the interosseous membrane; from an intermuscular septum between it and the 
Peronei, externally; and from the fascia covering the Tibialis posticus internally. 
The fibres pass obliquely downward and backward, and terminate in a tendon 
which occupies nearly the whole length of the posterior surface of the muscle. 
This tendon occupies a groove on the posterior surface of the lower end of the 
tibia; it then lies in a second groove on the posterior surface of the astragalus, and 
finally in a third groove, beneath the sustentaculum tali of the os calcis, and 
passes into the sole of the foot, where it runs forward between the two heads of 
the Flexor brevis hallucis, and is inserted into the base of the last phalanx of the 
great toe (Fig. 355,). The grooves in the astragalus and os calcis, which contain 
the tendon of the muscle, are converted by tendinous fibres into distinct canals 
lined by synovial membrane; and as the tendon crosses the sole of the foot, it is 
connected to the common flexor by a tendinous slip. 
Relations.-By its superficial surface, with the Soleus and tendo Achillis, from 
which it is separated by the deep transverse fascia; by its deep surface, with the 
fibula, Tibialis posticus, the peroneal vessels, the lower part of the interosseous 
membrane, and the ankle-joint; by its outer border, with the Peronei; by its inner 
border, with the Tibialis posticus and posterior tibial vessels and nerve. In the 
sole of the foot it lies above the Abductor hallucis and Flexor longus digitorum. 
The Flexor Longus Digitorum fm. flexor digitorum longus) is situated on 
the tibial side of the leg. At its origin it is thin and pointed, but gradually 
increases in size as it descends. It arises from the posterior surface of the shaft 
of the tibia, immediately below the oblique line to within three inches of its 
extremity, internal to the tibial origin of the Tibialis posticus; some fibres also 
arise from the fascia covering the Tibialis posticus. The fibres terminate in a 
tendon which runs nearly the whole length of the posterior surface of the muscle. 
This tendon passes behind the internal malleolus in a groove, common to it and 
the Tibialis posticus, but separated from the latter by a fibrous septum, each 
tendon being contained in a special sheath lined by a separate synovial membrane. 
It then passes obliquely forward and outward, superficial to the internal lateral 
ligament, into the sole of the foot (Fig. 355), where, crossing superficially to the 
tendon of the Flexor longus hallucis,1 to which it is connected by a strong 
tendinous slip, it becomes expanded, is joined by the Flexor accessorius, and finally 
divides into four tendons which are inserted into the bases of the last phalanges 
of the four lesser toes, each tendon passing through a fissure in the tendon of the 
Flexor brevis digitorum opposite the base of the first phalanges (Fig. 354). 
Relations.-In the leg: by its superficial surface, with the posterior tibial vessels 
and nerve, and the deep transverse fascia, which separates it from the Soleus 
muscle; by its deep surface, with the Tibia and Tibialis posticus. In the foot it is 
covered by the Abductor hallucis and Flexor brevis digitorum, and crosses super- 
ficial to the Flexor longus hallucis. 
The Tibialis Posticus (m. tibialis posterior) lies between the two preceding 
muscles, and is the most deeply seated of all the muscles in the leg. It com- 
1 That is, in the order of dissection of the sole of the foot. THE FIBULAR REGION 
539 
mences above by two pointed processes, separated by an angular interval, 
through which the anterior tibial vessels pass forward to the front of the leg. 
It arises from the whole of the posterior surface of the interosseous membrane, 
excepting its lowest part, from the outer portion of the posterior surface of the 
shaft of the tibia, between the commencement of the oblique line above, and the 
junction of the middle and lower third of the shaft below; and from the upper 
two-thirds of the internal surface of the fibula; some fibres also arise from the 
deep transverse fascia and from the intermuscular septa, separating it from the 
adjacent muscles on each side. This muscle, in the lower fourth of the leg, 
passes in front of the Flexor longus digitorum, and terminates in a tendon which 
passes through a groove behind the inner malleolus with the tendon of that 
muscle, but enclosed in a separate sheath; it then passes through another sheath, 
over the internal lateral ligament into the foot, and then beneath the inferior 
calcaneo-scaphoid ligament, and is inserted into the tuberosity of the scaphoid 
and internal cuneiform bones (Fig. 356). The tendon of this muscle contains a 
sesamoid fibro-cartilage as it passes over the scaphoid bone, and gives off fibrous 
expansions, one of which passes backward to the sustentaculum tali of the os calcis, 
others outward to the middle and external cuneiform and cuboid, and some 
forward to the base of the second, third, and fourth metatarsal bones (Fig. 355). 
Relations.-By its superficial surjace, with the Soleus, from which it is separated 
by the deep transverse fascia, the Flexor longus digitorum, the posterior tibial 
vessels and nerve, and the peroneal vessels; by its deep surjace, with the inter- 
osseous ligament, the tibia, fibula, and ankle-joint. 
Nerves.-The Popliteus is supplied by the fourth and fifth lumbar and first sacral 
nerves, through the internal popliteal; the Flexor longus digitorum and Tibialis 
posticus by the fifth lumbar and first sacral; and the Flexor longus hallucis by the 
fifth lumbar and first and second sacral nerves through the posterior tibial. 
Actions.-The Popliteus assists in flexing the leg upon the thigh; when the leg 
is flexed, it will rotate the tibia inward. It is especially called into action at the 
commencement of the act of bending the knee, inasmuch as it produces a slight 
inward rotation of the tibia, which is essential in the early stage of this movement. 
The Tibialis posticus is a direct extensor of the foot at the ankle-joint; acting in 
conjunction with the Tibialis anticus, it turns the sole of the foot inward (i. e., 
inverts the foot), antagonizing the Peronei, which turn it outward (evert it). In 
the sole of the foot the tendon of the Tibialis posticus lies directly below the inferior 
calcaneo-scaphoid ligament, and is therefore an important factor in maintaining 
the arch of the foot. The Flexor longus digitorum and Flexor longus hallucis are 
the direct flexors of the phalanges, and, continuing their action, extend the foot 
upon the leg; they assist the Gastrocnemius and Soleus in extending the foot, as in 
the act of walking or in standing on tiptoe. In consequence of the oblique direction 
of the tendon of the long flexor the toes would be drawn inward were it not for the 
Flexor accessorius muscle, which is inserted into the outer side of its tendon and 
draws it to the middle line of the foot during its action. "Faking their fixed point 
from the foot, these muscles serve to maintain the upright posture by steadying 
the tibia and fibula perpendicularly upon the ankle-joint. They also serve to raise 
these bones from the oblique position they assume in the stooping posture. 
7. The Fibular Region (Fig. 353). 
Peroneus longus. 
Peroneus brevis. 
Dissection.-The muscles are readily exposed by removing the fascia covering their surface, 
from below upward, in the line of direction of their fibres. 
The Peroneus Longus (m. peronaus longus) is situated at the upper part of 
the outer side of the leg, and is the more superficial of the two muscles. It arises 540 
THE MUSCLES AND FASCIAE 
from the head and upper two-thirds of the outer surface of the shaft of the fibula, 
from the deep surface of the fascia, and from the intermuscular septa between it 
and the muscles on the front, and those on the back of the leg, occasionally also 
by a few fibres from the outer tuberosity of the tibia. Between its attachment 
to the head and to the shaft of the fibula there is a small interval of bone from 
which no muscular fibres arise; through this gap the external popliteal nerve passes 
beneath the muscle. The muscle terminates in a long tendon, which passes behind 
the outer malleolus, in a groove common to it and the tendon of the Peroneus 
brevis, behind which it lies, the groove being converted into a canal by a fibrous 
band, and the tendons being invested by a common synovial membrane; it is 
then reflected obliquely forward across the outer side of the os calcis, below its 
peroneal tubercle, being contained in a separate fibrous sheath, lined by a pro- 
longation of the synovial membrane which lines the groove behind the malleolus. 
Having reached the outer side of the cuboid bone, it runs in a groove on the 
under surface of that bone, which is converted into a canal by the long calcaneo- 
cuboid ligament, and is lined by a synovial membrane: the tendon then crosses 
the sole of the foot obliquely, and is inserted into the outer side of the base of the 
metatarsal bone of the great toe and the internal cuneiform bone (Figs. 355 and 
356). Occasionally it sends a slip to the base of the second metatarsal bone. The 
tendon changes its direction at two points: first, behind the external malleolus; 
secondly, on the outer side of the cuboid bone; in both of these situations the 
tendon is thickened, and in the latter a sesamoid fibro-cartilage, or sometimes a 
bone, is usually developed in its substance. 
Relations.-By its superficial surface, with the fascia and integument; by its 
deep surface, with the fibula, external popliteal nerve, the Peroneus brevis, os 
calcis, and cuboid bone; by its anterior border, with an intermuscular septum,, 
which intervenes between it and the Extensor longus digitorum; by its posterior 
border, with an intermuscular septum, which separates it from the Soleus above 
and the Flexor longus hallucis below. 
The Peroneus Brevis (m. peronoeus brevis) lies beneath the Peroneus longus, 
and is shorter and smaller than it. It arises from the lower two-thirds of the 
external surface of the shaft of the fibula, internal to the Peroneus longus, and 
from the intermuscular septa separating it from the adjacent muscles on the front 
and back part of the leg. The fibres pass vertically downward, and terminate in 
a tendon which runs in front of that of the preceding muscle through the same 
groove, behind the external malleolus, being contained in the same fibrous 
sheath and lubricated by the same synovial membrane. It then passes through 
a separate sheath on the outer side of the os calcis, above that for the tendon of 
the Peroneus longus, the two tendons being here separated by the peroneal 
tubercle, and is finally inserted into the tuberosity at the base of the metatarsal 
bone of the little toe, on its outer side. 
Relations.-By its superficial surface, with the Peroneus longus and the fascia 
of the leg and foot; by its deep surface, with the fibula and outer side of the os 
calcis. 
Nerves.-The Peroneus longus and brevis are supplied by the fourth and fifth 
lumbar and first sacral nerves through the musculo-cutaneous branch of the 
external popliteal nerve. 
Actions.-The Peroneus longus and brevis extend the foot upon the leg, in 
conjunction with the Tibialis posticus, antagonizing the Tibialis anticus and 
Peroneus tertius, which are flexors of the foot. The Peroneus longus also everts 
the sole of the foot; hence the extreme eversion occasionally observed in fracture 
of the lower end of the fibula, where that bone offers no resistance to the action 
of this muscle. From the oblique direction of the Peroneus longus tendon across 
the sole of the foot it is an important agent in the maintenance of the transverse OF THE FOOT 
541 
arch of the foot. Taking their fixed point below, the Peronei serve to steady the 
leg upon the foot. This is especially the case in standing upon one leg, when 
the tendency of the superincumbent weight is to throw the leg inward: the 
Peroneus longus overcomes this tendency by drawing on the outer side of the 
leg, and thus maintains the perpendicular direction of the limb. 
Surgical Anatomy.-The student should now consider the position of the tendons of the 
various muscles of the leg, their relation with the ankle-joint and surrounding blood-vessels, and 
especially their action upon the foot, as their rigidity and contraction give rise to one or other of 
the kinds of deformity known as club-foot. The most simple and common deformity, and one 
that is rarely, if ever, congenital, is the talipes equinus, the Keel being raised by rigidity and con- 
traction of the Gastrocnemius muscle, and the patient walking upon the ball of the foot. In the 
talipes varus the foot is forcibly adducted and the inner side of the sole raised, sometimes to a 
right angle with the ground, by the action of the Tibialis anticus and posticus. In the talipes 
valgus the outer edge of the foot is raised by the Peronei muscles, and the patient walks on the 
inner ankle. In the talipes calcaneus the toes are raised by the Extensor muscles, the heel is 
depressed, and the patient walks upon it. Other varieties of deformity are met with, as the 
talipes equino-varus, equino-valgus, and calcaneo-valgus, whose names sufficiently indicate their 
nature. Of these, the talipes equino-varus is the most common congenital form: the heel is 
raised by the tendo Achillis, the inner border of the foot drawn upward by the Tibialis anticus, 
the anterior two-thirds twisted inward by the Tibialis posticus, and the arch increased by the 
contraction of the plantar fascia, so that the patient walks on the middle of the outer border of 
the foot. Each of these deformities may sometimes be successfully relieved by division of the 
opposing tendons and fascia; by this means the foot regains its proper position, and the tendons 
subsequently heal. The operation is easily performed by putting the contracted tendon upon 
the stretch, and dividing it by means of a narrow, sharp-pointed knife inserted beneath it. 
Pes cavus or hollow foot is accentuation of the longitudinal arch. Pes planus or flat-foot has 
been discussed elsewhere. 
Rupture of a few of the fibres of the Gastrocnemius may take place. Rupture of the Plantaris 
tendon not uncommonly occurs, especially in men somewhat advanced in life, from some sudden 
exertion, and frequently occurs during the game of lawn tennis, and is hence known as lawn- 
tennis leg. The accident is accompanied by a sudden pain, and produces a sensation as if the 
individual had been struck a violent blow on the part. The tendo Achillis is also sometimes 
ruptured. It is stated that John Hunter ruptured his tendo Achillis whilst dancing at the 
age of forty. The retro-calcaneal bursa is interposed between the posterior surface of the os 
calcis and the tendo Achillis, just above the point of insertion of the tendon. If it inflames 
it produces disabling pain (achillodynia, or Albert's disease, retro-calcaneal bursitis'). This bursa 
may become cartilaginous or osteophytes may form on the surface toward the os calcis. 
IV. MUSCLES AND FASCIA OF THE FOOT. 
The fibrous bands, or thickened portions of the fascia of the leg, which bind down the tendons 
in front of and behind the ankle in their passage to the foot should now be examined; they are 
termed the annular ligaments, and are three in number-anterior, internal, and external. 
The Anterior Annular Ligament (Fig. 350) consists of a superior or transverse portion 
(ligamentum transversum cruris) which binds down the Extensor tendons as they 
descend on the front of the tibia and fibula; and an inferior or Y-shaped portion 
(ligamentum cruciatum cruris), which retains them in connection with the tarsus, 
the two portions being connected by a thin intervening layer of fascia. The 
transverse portion is attached externally to the lower end of the fibula and inter- 
nally to the tibia; above it is continuous with the fascia of the leg; it contains 
only one synovial sheath, for the tendon of the Tibialis anticus; the other tendons 
and the anterior tibial vessels and nerve passing beneath it, but without any dis- 
tinct synovial sheath. The Y-shaped portion is placed in front of the ankle-joint, 
the stem of the Y, the fundiform ligament of Retzius, being attached externally to 
the upper surface of the os calcis, in front of the depression for the interosseous 
ligament; it is directed inward, as a double layer, one lamina passing in front, 
and the other behind, the tendons of the Peroneus tertius and Extensor longus 
digitorum. At the inner border of the latter tendon these two layers join together, THE MUSCLES AND FASCIA 
542 
forming a sort of loop or sheath in which the tendons are enclosed, surrounded 
by a synovial membrane. From the inner extremity of this loop the two limbs 
of the Y diverge: one passes upward and inward, to be attached to the internal 
malleolus, passing over the Extensor proprius hallucis and the vessels and nerves, 
but enclosing the Tibialis anticus and its synovial sheath by a splitting of its 
fibres. The other limb extends downward and inward to be attached to the 
inner border of the plantar fascia, and passes over the tendons of the Extensor 
proprius hallucis and Tibialis anticus and also the vessels and nerves. These 
two tendons are contained in separate synovial sheaths situated beneath the 
ligament. 
The Internal Annular Ligament (ligamentum laciniatum) is a strong fibrous 
band which extends from the inner malleolus above to the internal margin of the 
os calcis below, converting a series of grooves in this situation into canals for the 
passage of the tendons of the Flexor muscles and vessels into the sole of the foot. 
It is continuous by its upper border with the deep fascia of the leg, and by its lower 
border with the plantar fascia and the fibres of origin of the Abductor hallucis 
muscle. The four canals which it forms transmit, counting from before back- 
ward, first, the tendon of the Tibialis posticus;'second, the tendon of the Flexor 
longus digitorum; third, the posterior tibial vessels and nerve, which run through 
a broad space beneath the ligament; lastly, in a canal formed partly by the 
astragalus, the tendon of the Flexor longus hallucis. The canals for the tendons 
are lined by a separate synovial membrane. 
The External Annular Ligament is divided into two portions; a superior por- 
tion (retinaculum mm. peronoeorum superius), which extends from the extremity 
of the outer malleolus to the outer surface of the os calcis: it binds down the 
tendons of the Peroneus longus and brevis muscles in their passage behind the 
external malleolus. The two tendons are enclosed in one synovial sac. An 
inferior portion (retinaculum mm. peronoeorum injerius), which bridges the Peronei 
on the side of the os calcis and is attached to the bone above and below them. 
Dissection of the Sole of the Foot.-The foot should be placed on a high block with the 
sole uppermost, and firmly secured in that position. Carry an incision round the heel and along 
the inner and outer borders of the foot to the great and little toes. This incision should divide 
the integument and thick layer of granular fat beneath until the fascia is visible; the skin and fat 
should then be removed from the fascia in a direction from behind forward, as seen in Fig. 345. 
Plantar Fascia (aponeurosis plantaris).-The plantar fascia, the densest of all 
the fibrous membranes, is of great strength, and consists of pearly-white glisten- 
ing fibres, disposed, for the most part, longitudinally: it is divided into a central 
and two lateral portions. 
Central Portion.-The central portion, the thickest, is narrow behind and 
attached to the inner tubercle of the os calcis, posterior to the origin of the 
Flexor brevis digitorum, and, becoming broader and thinner in front, divides 
near the heads of the metatarsal bones into five processes, one for each of the toes. 
Each of these processes divides opposite the metatarso-phalangeal articulation 
into two strata, superficial and deep. The superficial stratum is inserted into 
the skin of the transverse sulcus which divides the toes from the sole. The 
deeper stratum divides into two slips which embrace the sides of the flexor tendons 
of the toes, and blend with the sheaths of the tendons, and laterally with the 
transverse metatarsal ligament, thus forming a series of arches through which 
the tendons of the short and long flexors pass to the toes. The intervals left 
between the five processes allow the digital vessels and nerves and the tendons 
of the Lumbricales muscles to become superficial. At the point of division of the 
fascia into processes and slips numerous transverse fibres are superadded, which 
serve to increase the strength of the fascia at this part by binding the processes THE DORSAL REGION 
543 
together and connecting them with the integument. The central portion of the 
plantar fascia is continuous with the lateral portions at each side, and sends 
upward into the foot, at their point of junction, two strong vertical intermuscular 
septa, broader in front than behind, which separate the middle from the external 
and internal plantar group of muscles; from these, again, thinner transverse 
septa are derived, which separate the various layers of muscles in this region. 
The upper surface of this fascia gives attachment behind to the Flexor brevis 
digitorum muscle. 
Lateral Portions.-The lateral portions of the plantar fascia are thinner than 
the central piece, and cover the sides of the foot. The outer portion covers the 
under surface of the Abductor minimi digiti; it is thick behind, thin in front, and 
extends from the os calcis, forward, to the base of the fifth metatarsal bone, into 
the outer side of which it is attached; it is continuous internally with the middle 
portion of the plantar fascia, and externally with the dorsal fascia. The inner 
portion is very thin, and covers the Abductor hallucis muscle; it is attached 
behind to the internal annular ligament, and is continuous around the side of 
the foot with the dorsal fascia, and externally with the middle portion of the 
plantar fascia 
Bursse about the Ankle and Foot.-(1) A subcutaneous bursa on the sole of 
the foot, beneath the tuberosity of the os calcis. (2) A subcutaneous bursa 
over the tendo Achillis (bursa subcutanea calcanea). (3) The retrocalcaneal 
bursa, between the posterior surface of the os calcis and the insertion of the 
tendo Achillis (bursa tendinis calcanei [Achillis]). (4) A bursa between the 
internal cuneiform bone and the tendon of the Tibialis anticus (bursa subten- 
dinea m. tibialis anterior is). (5) Bursae between the heads of the metatarsal 
bones (bursx intermetatarsophalangex). (6) A subcutaneous bursa over the 
internal malleolus (bursa subcutanea malleoli medialis). (7) Bursae between the 
scaphoid and middle cuneiform bones on the one hand and the tendon of the 
Tibialis posticus on the other (bursa subtendinea m. tibialis posterior is). (8) Bursae 
between the Lumbricales and the transverse ligaments (bursa' mm. lumbricalium 
ped is). (9) A bursa over the external malleolus (bursa subcutanea malleoli lateralis). 
(10) A bursa over the head of the first metatarsal bone. Various muscles have 
tendon-sheaths lined with synovial membrane (vaginal sheaths). 
Surgical Anatomy.-The dense plantar fascia aids powerfully in maintaining the arch of the 
foot. When this fascia stretches or gives way flat-foot forms. In some forms of club-foot 
the plantar fascia is contracted. This contraction is usually a secondary change. 
When inflammation causes tenderness and enlargement of the bursa over the metatarso- 
phalangeal articulation of the great toe, the enlargement is called a bunion. Enlargement of 
the retro-calcaneal bursa is known as Albert's disease, or achillodynia. 
8. The Dorsal Region (Fig. 350). 
Extensor brevis digitorum. 
Fascia (fascia dorsalis pedis).-The fascia on the dorsum of the foot is a thin 
membranous layer continuous above with the anterior margin of the annular 
ligament; it becomes gradually lost opposite the heads of the metatarsal bones, 
and on each side blends with the lateral portions of the plantar fascia; it forms a 
sheath for the tendons placed on the dorsum of the foot. On the removal of this 
fascia the muscles and tendons of the dorsal region of the foot are exposed. 
The Extensor Brevis Digitorum (m. extensor digitorum brevis) (Fig. 350) 
is a broad thin muscle which arises from the forepart of the upper and 
outer surfaces of the os calcis, in front of the groove for the Peroneus brevis, 
from the external calcaneo-astragaloid ligament, and from the common limb of 
the Y-shaped portion of the anterior annular ligament. It passes obliquely 544 
THE MUSCLES AND EASCLE 
across the dorsum of the foot, and terminates in four tendons. The innermost, 
which is the largest, is inserted into the dorsal surface of the base of the first 
phalanx of the great toe, crossing the dorsalis pedis artery; the other three, into 
the outer sides of the long extensor tendons of the second, third, and fourth toes. 
Relations.-By its superficial surjace, with the fascia of the foot, the tendons 
of the Extensor longus digitorum and Peroneus tertius; by its deep surjace, with 
the tarsal and metatarsal arteries and bones and the Dorsal interossei muscles. 
Nerves.-It is supplied by the anterior tibial nerve. 
Actions.-The Extensor brevis digitorum is an accessory to the long Extensor, 
extending the phalanges of the four inner toes, but acting only on the first phalanx 
of the great toe. The obliquity of its direction counteracts the oblique movement 
given to the toes by the long Extensor, so that, both muscles acting together, the 
toes are evenly extended. 
9. The Plantar Region (Figs. 354, 355, 356, 357, 358). 
The muscles in the plantar region of the foot may be divided into three groups, 
in a similar manner to those in the hand. Those of the internal plantar region 
are connected with the great toe, and correspond with those of the thumb; those 
of the external plantar region are connected with the little toe, and correspond 
with those of the little finger; and those of the middle plantar region are con- 
nected with the tendons intervening between the two former groups. But in order 
to facilitate the dissection of these muscles it will be found more convenient to 
divide them into four layers, as they present themselves, in the order in which 
they are successively exposed. 
The First Layer 
Abductor hallucis. 
Flexor brevis digitorum 
Abductor minimi digiti. 
Dissection.-Remove the fascia on the inner and outer sides of the foot, commencing in 
front over the tendons and proceeding backward. The central portion should be divided 
transversely in the middle of the foot, and the two flaps dissected forward and backward. 
The Abductor Hallucis lies along the inner border of the foot. It arises from 
the inner tubercle on the under surface of the os calcis; from the internal annular 
ligament; from the plantar fascia; and from the intermuscular septum between it 
and the Flexor brevis digitorum. The fibres terminate in a tendon which is 
inserted, together with the innermost tendon of the Flexor brevis hallucis, into 
the inner side of the base of the first phalanx of the great toe. 
Relations.-By its superficial surjace, with the plantar fascia; by its deep sur- 
face, with the Flexor brevis hallucis, the Flexor accessorius, and the tendons of 
the Flexor longus digitorum and Flexor longus hallucis, the Tibialis anticus and 
posticus, the plantar vessels and nerves. Its outer border is in relation to the 
Flexor brevis digitorum. 
The Flexor Brevis Digitorum (m. flexor digitorum brevis) lies in the 
middle of the sole of the foot, immediately beneath1 the plantar fascia, with 
which it is firmly united. It arises by a narrow tendinous process, from the 
inner tubercle of the os calcis, from the central part of the plantar fascia, and 
from the intermuscular septa between it and the adjacent muscles. It passes 
forward, and divides into four tendons, one for each of the four outer toes. 
Opposite the bases of the first phalanges each tendon divides into two slips, to 
allow of the passage of the corresponding tendon of the Flexor longus digitorum; 
1 That is, in order of dissection of the sole of the foot. THE PLANTAR REGION 
545 
the two portions of the tendon then unite and form a grooved channel for the 
reception of the accompanying long flexor tendon. Finally, they divide a second 
time, to be inserted into the sides of the second phalanges about their middle. The 
mode of division of the tendons of the Flexor brevis digitorum and their insertion 
into the phalanges is analogous to the division 
and insertion of the Flexor sublimis digitorum 
in the hand. 
Relations.-By its superficial surface, with 
the plantar fascia; by its deep surface, with the 
Flexor accessorius, the Lumbricales, the ten- 
dons of the Flexor longus digitorum, and the 
external plantar vessels and nerve, from which 
it is separated by a thin layer of fascia. The 
outer and inner borders are separated from the 
adjacent muscles by means of vertical pro- 
longations of the plantar fascia. 
Fibrous Sheaths of the Flexor Tendons.- 
These are not so well marked as in the fingers. 
The flexor tendons of the toes as they run 
along the phalanges are retained against the 
bones by a fibrous sheath, forming osseo- 
aponeurotic canals. These sheaths are formed 
by strong fibrous bands which arch across the 
tendons and are attached on each side to the 
margins of the phalanges. Opposite the mid- 
dle of the proximal and second phalanges the 
sheath is very strong, and the fibres pass 
transversely, but opposite the joints it is 
much thinner, and the fibres pass obliquely. 
Each sheath is lined by a synovial mem- 
brane which is reflected on the contained 
tendon. 
The Abductor Minimi Digiti (m. abductor 
digiti quinti) lies along the outer border of the 
foot. It arises, by a very broad origin, from 
the outer tubercle of the os calcis, from the 
under surface of the os calcis between the two 
tubercles, from the forepart of the inner 
tubercle, from the plantar fascia and the in- 
termuscular septum, between it and the Flexor 
brevis digitorum. Its tendon, after gliding 
over a smooth facet on the under surface of 
the base of the fifth metatarsal bone, is inserted 
with the short Flexor of the little toe into the outer side of the base of the first 
phalanx of this toe. 
Relations.-By its superficial surface, with the plantar fascia; by its deep sur- 
face, with the Flexor accessorius, the Flexor brevis minimi digiti, the long plantar 
ligament, and the tendon of the Peroneus longus. On its inner side are the 
external plantar vessels and nerve, and it is separated from the Flexor brevis 
digitorum by a vertical septum of fascia. 
Dissection.-The muscles of the superficial layer should be divided at their origin by insert- 
ing the knife beneath each, and cutting obliquely backward, so as to detach them from the 
bone; they should then be drawn forward, in order to expose the second layer, but not cut away 
at their insertion. The two layers are separated by a thin membrane, the deep plantar fascia, 
Fig. 354.-Muscles of the sole of the foot. 
First layer. 546 
THE MUSCLES AND FASCIAE 
on the removal of which is seen the tendon of the Flexor longus digitorum, the Flexor accessorius, 
the tendon of the Flexor longus hallucis, and the Lumbricales. The long flexor tendons 
diverge from each other at an acute angle; the Flexor longus hallucis runs along the inner side 
of the foot, on a plane superior to that of the Flexor longus digitorum, the direction of which is 
obliquely outward. 
The Second Layer. 
Flexor accessorius. 
Lumbricales. 
The Flexor Accessorius (m. quadratus planta') arises by two heads, which are 
separated from each other by the long plantar ligament: the inner or larger head, 
which is muscular, being attached to the inner concave surface of the os calcis 
below the groove which lodges the tendon of the Flexor longus digitorum; the 
outer head, flat and tendinous, to the outer surface of the os calcis, in front of its 
lesser tubercle, and to the long plantar ligament; the two portions join at an 
acute angle, and are inserted into the outer margin and upper and under sur- 
faces of the tendon of the Flexor longus digitorum, forming a kind of groove in 
which the tendon is lodged.1 
Relations.-By its superficial surface, with the muscles of the superficial layer, 
from which it is separated by the external plantar vessels and nerves; by its deep 
surface, with the os calcis and long calcaneo-cuboid ligament. 
The Lumbricales are four small muscles accessory to the tendons of the Flexor 
longus digitorum: they arise from the tendons of the long Flexor, as far back as 
their angle of division, each arising from two tendons, except the internal one. 
Each muscle terminates in a tendon, which passes forward on the inner side of 
the four lesser toes and is inserted into the expansion of the long Extensor tendon 
on the dorsum of the first phalanx of the corresponding toe. 
Dissection.-The flexor tendons should be divided at the back part of the foot, and the 
Flexor accessorius at its origin, and drawn forward, in order to expose the third layer. 
The Third Layer. 
Flexor brevis hallucis. 
Adductor obliquus hallucis. 
Flexor brevis minimi digiti. 
Adductor transversus hallucis. 
The Flexor Brevis Hallucis (m. flexor hallucis brevis) arises, by a pointed 
tendinous process, from the inner part of the under surface of the cuboid bone, 
from the contiguous portion of the external cuneiform, and from the prolongation 
of the tendon of the Tibialis posticus, which is attached to that bone. The 
muscle divides, in front, into two portions, which are inserted into the inner 
and outer sides of the base of the first phalanx of the great toe, a sesamoid bone 
being developed in each tendon at its insertion. The inner portion of this 
muscle is blended with the Abductor hallucis previous to its insertion, the outer 
portion with the Adductor obliquus hallucis, and the tendon of the Flexor 
longus hallucis lies in a groove between them. 
Relations.-By its superficial surface, with the Abductor hallucis and the ten- 
don of the Flexor longus hallucis; by its deep surface, with the tendon of the 
Peroneus longus and metatarsal bone of the great toe; by its inner border, with 
the Abductor hallucis; by its outer border, with the Adductor obliquus hallucis. 
The Adductor Obliquus Hallucis is a large, thick, fleshy mass passing obliquely 
across the foot and occupying the hollow space between the four inner meta- 
tarsal bones. It arises from the tarsal extremities of the second, third, and fourth 
metatarsal bones, and from the sheath of the tendon of the Peroneus longus, 
1 According to Turner, the fibres of the Flexor accessorius end in aponeurotic bands, which contribute slips 
to the second, third, and fourth digits. THE PLANTAR REGION 
547 
and is inserted, together with the outer portion of the Flexor brevis hallucis, into 
the outer side of the base of the first phalanx of the great toe. 
The small muscles of the great toe, the Abductor, Flexor brevis, Adductor 
obliquus, and Adductor transversus, like the similar muscles of the thumb, give 
□ff fibrous expansions, at their insertions, to blend with the long Extensor tendon. 
Fig. 355.-Muscles of the sole of the foot. 
Second layer. 
Fig. 356.-Muscles of the sole of the foot. 
Third layer. 
The Flexor Brevis Minimi Digiti (m. flexor digiti quinti brevis) lies on the meta- 
tarsal bone of the little toe, and much resembles one of the Interossei. It arises 
from the base of the metatarsal bone of the little toe, and from the sheath of the 
Peroneus longus; its tendon is inserted into the base of the first phalanx of 
the little toe on its outer side. Occasionally some of the deeper fibres of the 
muscle are inserted into the outer part of the distal half of the fifth metatarsal 
bone; these are described by some as a distinct muscle, the Opponens minimi 
digiti. 
Relations.-By its superficial surface, with the plantar fascia and tendon of 
the Abductor minimi digiti; by its deep surface, with the fifth metatarsal bone. 548 
THE MUSCLES AND FASCIAE 
The Adductor Transversus Hallucis (m. transversus pedis) is a narrow, flat, 
muscular fasciculus, stretched transversely across the heads of the metatarsal bones, 
between them and the flexor tendons. It arises from the inferior metatarso- 
phalangeal ligaments of the three outer toes, sometimes only from the third and 
fourth and from the transverse ligament of the metatarsus; and is inserted into 
the outer side of the first phalanx of the great toe, its fibres being blended with 
the tendon of insertion of the Adductor obliquus hallucis. 
Relations.-By its superficial surface, with the tendons of the long and short 
Flexors and Luinbricales; by its deep surface, with the Interossei. 
The Fourth Layer. 
The Interossei. 
The Interossei Muscles in the foot are similar to those in the hand, with this 
exception, that they are grouped around the middle line of the second toe, instead 
of the middle line of the third finger, as in the hand. They are seven in number, 
and consist of two groups, Dorsal and Plantar. 
Fig. 357.-The Dorsal interossei. Left foot. 
Fig. 358.-The Plantar interossei. Left foot. 
The Dorsal Interossei (m. interossei dor sales') Jour in number, are situated between 
the metatarsal bones. They are bipenniform muscles, arising by two heads from 
the adjacent sides of the metatarsal bones, between which they are placed; their 
tendons are inserted into the bases of the first phalanges, and into the aponeurosis 
of the common extensor tendon. In the angular interval left between the heads 
of each muscle at its posterior extremity the perforating arteries pass to the 
dorsum of the foot, except in the First interosseous muscle, where the interval 
allows the passage of the communicating branch of the dorsalis pedis artery. The 
First dorsal interosseous muscle is inserted into the inner side of the second toe; 
the other three are inserted into the outer sides of the second, third, and fourth toes. 
The Plantar Interossei (m. interossei plantares), three in number, lie beneath, 
rather than between, the metatarsal bones. They are single muscles, and are 
each connected with but one metatarsal bone. They arise from the base and SURFACE FORM OF THE LOWER EXTREMITY 
549 
inner sides of the shaft of the third, fourth, and fifth metatarsal bones, and are 
inserted into the inner sides of the bases of the first phalanges of the same toes, 
and into the aponeurosis of the common extensor tendon. 
Nerves.-The Flexor brevis digitorum, the Flexor brevis and Abductor hallucis, 
and the innermost Lumbrical1 are supplied by the internal plantar nerve. All 
the other muscles in the sole of the foot by the external plantar. The first dorsal 
interosseous muscle frequently receives an extra filament from the internal 
branch of the anterior tibial nerve on the dorsum of the foot, and the second 
dorsal interosseous a twig from the external branch of the same nerve. 
Actions.-All the muscles of the foot act upon the toes, and for purposes of 
description as regard their action may be grouped as Abductors, Adductors, 
Flexors, or Extensors. The Abductors are the Dorsal interossei, the Abductor 
hallucis, and the Abductor minimi digiti. The Dorsal interossei are abductors 
from an imaginary line passing through the axis of the second toe, so that the 
first muscle draws the second toe inward, toward the great toe; the second muscle 
draws the same toe outward; the third draws the third toe, and the fourth draws 
the fourth toe, in the same direction. lake the interossei in the hand, they also 
flex the proximal phalanges and extend the two terminal phalanges. The Abduc- 
tor hallucis abducts the great toe from the others, and also flexes the proximal 
phalanx of this toe. And in the same way the action of the Abductor minimi 
digiti is twofold-as an abductor of this toe from the others, and also as a flexor 
of the proximal phalanx. The Adductors are the Plantar interossei, the Adductor 
obliquus hallucis, and the Adductor transversus hallucis. The Plantar inter- 
osseous muscles adduct the third, fourth, and fifth toes toward the imaginary 
line passing through the second toe, and by means of their insertion into the 
aponeurosis of the extensor tendon they, with the dorsal interossei, flex the prox- 
imal phalanges and extend the two terminal phalanges. The Adductor obliquus 
hallucis is chiefly concerned in adducting the great toe toward the second one, 
but also assists in flexing this toe. The Adductor transversus hallucis approxi- 
mates all the toes, and thus increases the curve of the transverse arch of the 
metatarsus. The Flexors are the Flexor brevis digitorum, the Flexor accessorius, 
the Flexor brevis hallucis, the Flexor brevis minimi digiti, and the Lumbricales. 
The Flexor brevis digitorum flexes the second phalanges upon the first, and, con- 
tinuing its action, may flex the first phalanges also and bring the toes together. 
The Flexor accessorius assists the Long flexor of the toes, and converts the 
oblique pull of the tendons of that muscle into a direct backward pull upon the 
toes. The Flexor brevis hallucis flexes and slightly adducts the first phalanx of 
the great toe. The Flexor brevis minimi digiti flexes the little toe and draws its 
metatarsal bone downward and inward. The Lumbricales, like the correspond- 
ing muscles in the hand, assist in flexing the proximal phalanx, and by their 
insertion into the long Extensor tendon aid in straightening the two terminal 
phalanges. The only muscle in the Extensor group is the Extensor brevis digi- 
torum. It extends the first phalanx of the great toe, and assists the long Exten- 
sor in extending the next three toes, and at the same time gives to the toes an 
outward direction when they are extended. 
SURFACE FORM OF THE LOWER EXTREMITY. 
Of the muscles of the thigh, those of the iliac region have no influence on surface form, 
while those of the anterior femoral region, being to a great extent superficial, largely con- 
tribute to the surface form of this part of the body. The Tensor fasciae femoris pro- 
1 Formerly the two inner Lumbricales were described as being supplied by the internal plantar nerve. Brooks 
(Journal of Anatomy, vol. xxi. p. 575) in ten dissections found that in nine of them only the inner Lumbrical 
obtained its nerve supply from this source. In the tenth instance the first and second Lumbricales were 
supplied by both external and internal plantar. 550 
THE MUSCLES AND FASCIAE 
duces a broad elevation immediately below the anterior portion of the crest of the ilium and 
behind the anterior superior spinous process. From its lower border a longitudinal groove, 
corresponding to the ilio-tibial band, may be seen running down the outer side of the thigh to 
the outer side of the knee-joint. The Sartorius muscle, when it is brought into action by flexing 
the leg on the thigh and the thigh on the pelvis, and rotating the thigh outward, presents a 
well-marked surface form. At its upper part, where it constitutes the outer boundary of 
Scarpa's triangle, it forms a prominent oblique ridge, which becomes changed into a flattened 
plane below, and this gradually merges in a general fulness on the inner side of the knee-joint. 
When the Sartorius is not in action, a depression exists between the Quadriceps extensor and the 
Adductor muscles, running obliquely downward and inward from the apex of Scarpa's triangle 
to the inner side of the knee, which depression corresponds to this muscle. In the depressed angle 
formed by the divergence of the Sartorius and Tensor fasciae femoris muscles, just below the 
anterior superior spinous process of the ilium, the Rectus femoris muscle appears, and, below 
this, determines to a great extent the convex form of the front of the thigh. In a well-developed 
subject the borders of the muscle, when in action, are clearly to be defined. The Vastus externus 
forms a long flattened plane on the outer side of the thigh, traversed by the longitudinal groove 
formed by the ilio-tibial band. The Vastus internus, on the inner side of the lower half of the 
thigh, gives rise to a considerable prominence, which increases toward the knee and terminates 
somewhat abruptly in this situation with a full, curved outline. The Crureus and Subcrureus 
are completely hidden, and do not directly influence surface form. The Adductor muscles, 
constituting the internal femoral group, are not to be individually distinguished from each 
other, with the exception of the upper tendon of the Adductor longus and the lower tendon of 
the Adductor magnus. The upper tendon of the Adductor longus, when the muscle is in action, 
stands out as a prominent ridge, which runs obliquely downward and outward from the neigh- 
borhood of the pubic spine, and forms the inner boundary of a flattened triangular space on 
the upper part of the front of the thigh, known as Scarpa's triangle. The lower tendon of the 
Adductor magnus can be distinctly felt as a short ridge extending down to the Adductor tubercle 
on the internal condyle, between the Sartorius and Vastus internus. The Adductor group 
of muscles fills in the triangular space at the upper part of the thigh, formed between the oblique 
femur and the pelvic wall, and to them is due the contour of the inner border of the thigh, the 
Gracilis largely contributing to the smoothness of the outline. These muscles are not marked 
off on the surface from those of the posterior femoral region by any intermuscular marking; but 
on the outer side of the thigh these latter muscles are defined from the Vastus externus by a 
distinct marking, corresponding to the external intermuscular septum. The Gluteus maximus 
and a part of the Gluteus medius are the only muscles of the buttock which influence surface 
form. The other part of the Gluteus medius, the Gluteus minimus, and the External rotators 
are completely hidden. The Gluteus maximus forms the full rounded outline of the buttock; 
it is more prominent behind, compressed in front, and terminates at its tendinous insertion in 
a depression immediately behind the great trochanter. Its lower border does not correspond 
to the gluteal fold, but is much more oblique, being marked by a line drawn from the side of 
the coccyx to the junction of the upper with the lower two-thirds of the thigh on the outer side. 
From beneath the lower margin of this muscle the Hamstring muscles appear, at first narrow 
and not well marked, but as they descend becoming more prominent and widened out, and 
eventually dividing into two well-marked ridges, which constitute the upper boundaries of the 
popliteal space, and are formed by the tendons of the inner and outer hamstring muscles respect- 
ively. In the upper part of the thigh these muscles are not to be individually distinguished 
from each other, but lower down the separation between the Semitendinosus and Semimem- 
branosus is denoted by a slight intermuscular marking. The external hamstring tendon formed 
by the Biceps is seen as a thick cord running down to the head of the fibula. The inner ham- 
string tendons comprise the Semitendinosus, the Semimembranosus, and the Gracilis. The 
Semitendinosus is the most internal of these, and can be felt, in certain positions of the limb, 
as a sharp cord; the Semimembranosus is thick, and the Gracilis is situated a little farther 
forward than the other two. All the muscles on the front of the leg appear to a certain extent 
somewhere on the surface, but the form of this region is mainly dependent upon the Tibialis 
anticus and the Extensor longus digitorum. The Tibialis anticus is well marked, and presents 
a fusiform enlargement at the outer side of the tibia, and projects beyond the crest of the shin- 
bone. From the muscular mass its tendons may be traced downward, standing out boldly, 
when the muscle is in action, on the front of the tibia and ankle-joint, and coursing down to its 
insertion along the inner border of the foot. A well-marked groove separates this muscle exter- 
nally from the Extensor longus digitorum, which fills up the rest of the space between the upper 
part of the shaft of the tibia and fibula. It does not present so bold an outline as the Tibialis 
anticus, and its tendon below, diverging from the tendon of the Tibialis anticus, forms with the 
latter a sort of plane, in which may be seen the tendon of the Extensor proprius hallucis. A 
groove on the outer side of the extensor longus digitorum, seen most plainly when the muscle 
is in action, separates the tendon from a slight eminence corresponding to the Peroneus tertius. 
The fleshy fibres of the Peroneus longus are strongly marked at the upper part of the outer SURGICAL ANATOMY OF THE LOWER EXTREMITY 
551 
side of the leg, especially when the muscle is in action. It forms a bold swelling, separated by 
furrows from the Extensor longus digitorum in front and the Soleus behind. Below, the fleshy 
fibres terminate abruptly in a tendon which overlaps the more flattened form of the Peroneus 
brevis. At the external malleolus the tendon of the Peroneus brevis is more marked than that 
of the Peroneus longus. On the dorsum of the foot the tendons of the Extensor muscles, 
emerging from beneath the anterior annular ligament, spread out and can be distinguished 
in the following order: The most internal and largest is the Tibialis anticus, then the Extensor 
proprius hallucis ; next comes the Extensor longus digitorum, dividing into four tendons to 
the four outer toes; and lastly, most externally, is the Peroneus tertius. The flattened form of 
the dorsum of the foot is relieved by the rounded outline of the fleshy belly of the Extensor 
brevis digitorum, which forms a soft fulness on the outer side of the tarsus in front of the external 
malleolus, and by the Dorsal interossei, which bulge between the metatarsal bones. At the 
back of the knee is the popliteal space, bounded above by the tendons of the hamstring muscle; 
below, by the two heads of the Gastrocnemius. Below this space is the prominent fleshy mass 
of the calf of the leg, produced by the Gastrocnemius and Soleus. When these muscles are 
in action, as in standing on tiptoe, the borders of the Gastrocnemius are well defined, presenting 
two curved lines, which converge to the tendon of insertion. Of these borders, the inner is 
more prominent than the outer. The fleshy mass of the calf terminates somewhat abruptly 
below in the tendo Achillis, which stands out prominently on the lower part of the back of the 
leg. It presents a somewhat tapering form in the upper three-fourths of its extent, but widens 
out slightly below. When the muscles of the calf are in action, the lateral portions of the Soleus 
may be seen, forming curved eminences, of which the outer is the longer, on either side of the 
Gastrocnemius. Behind the inner border of the lower part of the shaft of the tibia a well- 
marked ridge, produced by the tendon of the Tibialis posticus, is visible when this muscle is in 
a state of contraction. On the sole of the foot the superficial layer of muscles influences surface 
form; the Abductor minimi digiti most markedly. This muscle forms a narrow rounded 
elevation along the outer border of the foot, while the Abductor hallucis does the same, though 
to a less extent, on the inner side. The Flexor brevis digitorum, bound down by the plantar 
fascia, is not very apparent; it produces a flattened form, covered by the thickened skin of the 
sole, which is here thrown into numerous wrinkles. 
SURGICAL ANATOMY OF THE LOWER EXTREMITY 
The student should now consider the effects produced by the action of the various muscles 
in fractures of the bones of the lower extremity. The more common forms of fractures are 
selected for illustration and description. 
PYRIFORMIS. 
-GEMELLUS SUPERIOR. 
OBTURATOR INTERNUS. 
GEMELLUS INFERIOR. 
OBTURATOR EXTERNUS. 
QUADRATUS FEMORIS. 
Fig. 359.--Fracture of the neck of the femur within the capsular ligament. 
In fracture of the neck of the femur internal to the capsular ligament (Fig. 359) the charac- 
teristic marks are slight shortening of the limb and eversion of the foot, neither of which symp- 552 
THE MUSCLES AND FASCIAE 
toms occurs, however, in some cases until some time after the injury. The eversion is caused 
by the weight of the limb rotating it outward. The shortening is produced by the action of the 
Glutei, and by the Rectus femoris in front and the Biceps, Semitendinosus, and Semimem- 
branosus behind. The treatment is extension by means of adhesive plaster and weights and 
counter-extension by raising the foot of the bed, eversion being corrected by sand-bags. In 
some cases Thomas's splint is used. 
In fracture of the femur just below the trochanters (Fig. 3G0) the upper fragment, the por- 
tion chiefly displaced, is tilted forward almost at right angles with the pelvis by the combined 
action of the Psoas and Iliacus, and, at the same time, everted 
and drawn outward by the External rotator and Glutei muscles, 
causing a marked prominence at the upper and outer side of the 
thigh, and much pain from the bruising and laceration of the 
muscles. The limb is shortened, in consequence of the lower 
fragment being drawn upward by the rectus in front, and the 
Biceps, Semimembranosus, and Semitendinosus behind, and is 
at the same time everted. This fracture may be reduced by 
direct relaxation of all the opposing muscles, to effect which the 
limb should be put up in such a manner that the thigh is flexed 
on the pelvis and the leg on the thigh, the extremity being placed 
SEMI- 
MEM BRANOSUS. 
SEMI* 
TENDINOSUS. 
Fig. 360.-Fracture of the femur 
below the trochanters. 
Fig. 361.-Fracture of the femur 
above the condyles. 
Fig. 362.-Fracture of 
the patella 
upon a double inclined plane and extension being made in the axis of the partly flexed 
thigh by means of adhesive plaster and weights. In some cases it is necessary to incise and 
wire the fragments together. 
Oblique fracture of the femur immediately above the condyles (Fig. 361) is a formidable 
injury, and attended with considerable displacement. On examination of the limb the lower 
fragment may be felt deep in the popliteal space, being drawn backward by the Gastrocnemius 
and Plantaris muscles, and upward by the Hamstring and Rectus muscles. The pointed end 
of the upper fragment is drawn inward by the Pectineus and Adductor muscles, and tilted for- 
ward by the Psoas and Iliacus, piercing the Rectus muscle and occasionally the integument. 
Relaxation of these muscles and direct approximation of the broken fragments are effected by 
placing the limb on a double inclined plane. The greatest care is requisite in keeping the 
pointed extremity of the upper fragment in proper position; otherwise, after union of the 
fracture, the power of extension of the limb is partially destroyed from the Rectus muscle being 
held down by the fractured end of the bone, and from the patella, when elevated, being drawn 
upward against the projecting fragment. 
In fracture of the patella (Fig. 362) the fragments are separated by the effusion which takes 
place into the joint, and by the action of the Quadriceps extensor; the extent of separation of 
the two fragments depending upon the degree of laceration of the ligamentous structures 
around the bone. Some cases may be treated by a posterior straight splint, the fragments 
being pulled together by strips of adhesive plaster. In many cases it is advisable to incise, 
remove intervening pieces of fibrous tissue and wire the fragments together. SURGICAL ANATOMY OF THE LOWER EXTREMITY 
553 
The tibia is fractured most commonly by indirect force at the junction of the middle third 
with the lower third of the shaft. Compound fractures are more common in the leg than 
in any other region of the body because the tibia is such a superficial bone and is so much 
exposed to injury. Most fractures from indirect force are oblique. 
In oblique fracture of the shaft of the tibia (Fig. 363), if the fracture has taken place obliquely 
from above, downward and forward, the fragments ride over one another, the lower fragments 
being drawn backward and upward by the powerful action of the muscles of the calf; the 
pointed extremity of the upper fragment projects forward immediately beneath the integu- 
ment, often protruding through it and rendering the fracture a compound one. If the direc- 
tion of the fracture is the reverse of that shown in the figure, the pointed extremity of the lower 
fragment projects forward, riding upon the lower end of the upper one. By bending the knee. 
Fig. 363.-Oblique fracture of 
the shaft of the tibia. 
Fig. 364.-Fracture of the fibula with dislocation of 
the foot outward-" Pott's fracture." 
which relaxes the opposing muscles, and making extension from the ankle and counter- 
extension at the knee, the fragments may be brought into apposition. It is often necessary, 
however, in a compound fracture, to remove a portion of the projecting bone with the saw 
before complete adaptation can be effected. 
Fracture of the fibula with dislocation of the foot outward (Fig. 364), commonly known as 
Pott's fracture, is one of the most frequent injuries of the ankle-joint. The fibula is frac- 
tured about three inches above the ankle; in addition to this the internal malleolus is broken 
off, or the deltoid ligament torn through, and the end of the tibia displaced from the correspond- 
ing surface of the astragalus. The foot is markedly everted, and the sharp edge of the upper 
end of the fractured malleolus presses strongly against the skin; at the same time, the heel is 
drawn up by the muscles of the calf. This injury can generally be reduced by flexing the leg at 
right angles with the thigh, which relaxes all the opposing muscles, and by making extension 
from the ankle and counter-extension at the knee. THE BLOOD-VASCULAR SYSTEM. 
ANGIOLOGY is the branch of anatomy which treats of the blood-vessels. 
The blood-vascular system comprises the heart and blood-vessels with 
their contained fluid, the blood. 
The Heart is the central organ of the entire system, and is a hollow muscle; 
by its contraction the blood is pumped to all parts of the body through a com- 
plicated series of tubes, termed arteries. The arteries undergo almost infinite 
ramification in their course throughout the body, and end in very minute vessels, 
called arterioles, which in their turn open into a close-meshed network of micro- 
scopic vessels, termed capillaries. After the blood has passed through the capil- 
laries it enters into minute vessels called venules and from them it is collected 
into a series of larger vessels, called veins, by which it is returned to the heart. 
The passage of the blood through the heart and blood-vessels constitutes what is 
termed the circulation of the blood, of which the following is an outline. 
The human heart is divided by a septum into two halves, right and left, each 
half being further constricted into two cavities, the upper of the two being termed 
the auricle and the lower the ventricle. The heart therefore consists of four 
chambers or cavities, two forming the right half, the right auricle and right 
ventricle; and two the left half, the left auricle and left ventricle. The right 
half of the heart contains venous or impure blood; the left, arterial or pure blood. 
From the cavity of the left ventricle the pure blood is carried into a large artery, 
the aorta, through the numerous branches of which it is distributed to all parts 
of the body, with the exception of the lungs. In its passage through the capil- 
laries of the body the blood gives up to the tissues the materials necessary for 
their growth and nourishment, and at the same time receives from the tissues the 
waste products resulting from their metabolism, and in doing so becomes changed 
from arterial or pure blood into venous or impure blood, which is collected by the 
veins and through them returned to the right auricle of the heart. From this 
cavity the impure blood passes into the right ventricle, from which it is conveyed 
through the pulmonary arteries to the lungs. In the capillaries of the lungs it 
again becomes arterialized, and is then carried to the left auricle by the pulmonary 
veins. From this cavity it passes into that of the left ventricle, from which the 
cycle once more begins. 
The course of the blood from the left ventricle through the body generally to 
the right side of the heart constitutes the greater or systemic circulation, while its 
passage from the right ventricle through the lungs to the left side of the heart is 
termed the lesser or pulmonary circulation. 
It is necessary, however, to state that the blood which circulates through the 
spleen, pancreas, stomach, small intestine, and the greater part of the large intes- 
tine is not returned directly from these organs to the heart, but is collected into 
a large vein, termed the portal vein, by which it is carried to the liver. In the 
liver this vein divides, after the manner of an artery, and ultimately ends in 
capillary vessels, from which the rootlets of a series of veins, called the hepatic 
veins, arise; these carry the blood into the inferior vena cava, which conveys it 
to the right auricle. 
555 556 
THE BLOOD- VASCULAR SYSTEM 
From this it will be seen that the blood contained in the portal vein passes 
through two sets of capillary vessels: (1) those in the spleen, pancreas, stomach, 
etc., and (2) those in the liver. 
Speaking generally, the arteries may be said to contain pure, and the veins 
impure, blood. This is true of the systemic, but not of the pulmonary, vessels, 
since it has been seen that the impure blood is conveyed from the heart to the 
lungs by the pulmonary arteries, and the pure blood returned from the lungs to 
the heart by the pulmonary veins. Arteries, 
therefore, must be defined as vessels which 
convey blood from the heart, and veins as 
vessels which return blood to the heart. 
The heart and lungs are contained within 
the cavity of the thorax, the walls of which 
afford them protection (Fig. 366). The heart 
lies between the two lungs, and is there 
enclosed within a sero-membranous bag, the 
pericardium, while each lung is invested by a 
serous membrane, the pleura. The skeleton 
of the thorax was described on page 155. 
The Cavity of the Thorax (cavum tho- 
racis).-The capacity of the cavity of the 
thorax does not correspond with its apparent 
size externally, because (1) the space en- 
closed by the lower ribs is occupied by some 
of the abdominal viscera; and (2) the cavity 
extends above the first rib into the neck. 
The size of the cavity of the thorax is con- 
stantly varying during life, with the move- 
ments of the ribs and diaphragm, and with 
the degree of distention of the abdominal 
viscera. From the collapsed state of the 
lungs, as seen when the thorax is opened, 
in the dead body, it would appear as if the 
viscera only partly filled the cavity of the 
thorax, but during life there is no vacant 
space, that which is seen after death being 
filled up during life by the expanded lungs. 
The Upper Opening of the Thorax 
(apertura thoracis superior). - The parts 
which pass through the upper opening of 
the thorax are, from before backward in or 
near the middle line, the Sterno-hyoid and 
Sterno-thyroid muscles, the remains of the 
thymus gland, the trachea, oesophagus, thoracic duct, the inferior thyroid veins, 
and the Longus colli muscle of each side; at the sides, the innominate artery, 
the left common carotid, and left subclavian arteries, the internal mammary 
and superior intercostal arteries, the right and left innominate veins, the pneu- 
mogastric, cardiac, phrenic, and sympathetic nerves, the anterior branch of the 
first dorsal nerve, and the recurrent laryngeal nerve of the left side. The 
apex of each lung, covered by the pleura, also projects through this aperture, a 
little above the margin of the first rib. 
The Lower Opening of the Thorax (apertura thoracis inferior) is wider trans- 
versely than from before backward. It slopes obliquely downward and back- 
ward, so that the cavity of the thorax is much deeper behind than in front. The 
Pulmonary Capillaries 
Pulmonary 
Arteries 
Pulmonary 
Veins 
Systemic Veins 
Hepatic Veins 
Portal 
Vein 
Fig. 365.-Diagram to show the course of the 
circulation of the blood. THE PERICARDIUM 
557 
Diaphragm (see page 427) closes in the opening, forming the floor of the thorax. 
The floor is flatter at the centre than at the sides, and is higher on the right side 
than on the left, corresponding in the dead body to the upper border of the fifth 
Fig. 366.-Front view of the thorax. The ribs and sternum are represented in relation to the lungs, heart, 
and other internal organs. 1.' Pulmonary orifice. 2. Aortic orifice. 3. Left auriculo-ventricular orifice. 4. 
Right auriculo-ventricular orifice. 
costal cartilage on the former, and to the corresponding part of the sixth costal 
cartilage on the latter. From the highest point on each side the floor slopes sud- 
denly downward to the attachment of the Diaphragm to the ribs; this is more 
marked behind than in front, so that only a narrow space is left between it and 
the wall of the thorax. 
THE PERICARDIUM. 
The pericardium (Figs. 367, 368, 369, 370, 371, and 372) is a conical sero- 
membranous sac, placed in the middle mediastinum. In this sac the heart and 
the commencement of the great vessels are contained. It is placed behind the 
sternum and the cartilages of the third, fourth, fifth, sixth, and seventh ribs of 
the left side, in the interval between the pleurte. 
Its apex is directed upward, and surrounds the great vessels about two inches 
above their origin from the base of the heart. Its base is attached to the central 
tendon and to the left part of the adjoining muscular structure of the Diaphragm. 
In front it is separated from the sternum by the remains of the thymus gland 558 
THE BLOOD-VASCULAR SYSTEM 
above and a little loose areolar tissue below, and is covered by the margins of the 
lungs, especially the left. Behind, it rests upon the bronchi, the oesophagus, and 
the descending aorta. Laterally, it is covered by the pleurae, and is in relation to 
the inner surface of the lungs; the phrenic nerve with its accompanying vessels 
descends between the pericardium and pleura on either side (Fig. 371). 
Structure of the Pericardium.-The pericardium is a fibro-serous membrane, 
and consists, therefore, of two layers, an external fibrous and an internal serous. 
Right sub- 
'clavian art. 
Left common 
carotid art. 
Right common 
carotid artery. 
Left sub- 
clavian 
artery. 
Inferior thyroid 
vein. 
Left innomi-' 
nate vein. 
Right innomi-. 
nate vein. 
Superior vena- 
cava. 
Right pulmo- 
nary veins. 
Left pul- 
monary 
veins. 
Fio. 367.-Pericardium from in front. The sac has been distended with plaster. (From a preparation 
in the Museum of the Royal College of Surgeons of England.) 
The Fibrous Layer is a strong, dense, connective-tissue membrane. Above, it 
surrounds the great vessels arising from the base of the heart, on which it is 
continued in the form of tubular prolongations which are gradually lost upon 
their external coat, the strongest being that which encloses the aorta. The peri- 
cardium may be traced over these vessels, to become continuous with the deep 
layer of the cervical fascia. The prolongations to the cervical fascia constitute the 
vertebro-pericardial ligaments (Fig. 370). In front the pericardium is connected to 
the posterior surface of the sternum by two fibrous bands, the superior and inferior 
sterno-pericardiac ligaments or ligaments of Luschka (ligamenta sternopericardiaca) 
(Fig. 370). The superior sterno-pericardial ligament, called also the sternocosto- THE PERICARDIUM 
559 
pericardial ligament (Fig. 370), passes to the manubrium. The inferior sterno- 
pericardial ligament, called also the xipho-pericardial ligament (Fig. 370), passes to 
the ensiform cartilage. On each side of the ascending aorta the pericardium sends 
upward a diverticulum: the one on the left side, somewhat conical in shape, passes 
upward and outward, between the arch of the aorta and the pulmonary artery, 
as far as the ductus arteriosus, where it terminates in a caecal extremity, which is 
attached by loose connective tissue to the obliterated duct (Fig. 367). The one on 
the right side passes upward and to the right, between the ascending aorta and 
Right subclavian artery. 
Left subclavian artery.. 
Left common 
carotid artery. 
Right pulmonary artery. 
Right common 
carotid artery. 
Inferior thyroid 
vein. 
Vena azygos 
major. 
Right pulmonary 
veins. 
Fig. 368.-Pericardium from behind. (From the same preparation as the preceding figure.) 
vena cava superior, and also terminates in a caecal extremity. Below, the fibrous 
layer is attached to the central tendon of the Diaphragm, and on the left side to 
its muscular fibres. The pericardium is fixed to the Diaphragm by the anterior 
phreno-pericardial ligament and by the lateral phreno-pericardial ligaments (Fig. 370). 
The vessels receiving fibrous prolongations from this membrane are the aorta 
the superior vena cava, the right and left pulmonary arteries, and the four pulmo- 
nary veins. The inferior vena cava enters the pericardium through the central 
tendon of the Diaphragm, and consequently it receives no covering from the 
fibrous layer (Fig. 371). 560 
THE BLOOD-VASCULAR SYSTEM 
The Serous Pericardium invests the heart, and is then reflected on the inner sur- 
face of the fibrous pericardium. It consists, therefore, of a visceral layer (epicar- 
dium) and a parietal layer. The former invests the surface of the heart, and the 
commencement of the great vessels, to the extent of an inch and a half from 
their origin; from these it is reflected upon the inner surface of the fibrous layer. 
The serous membrane encloses the aorta and pulmonary artery in a single tube, 
so that a passage, termed the great transverse sinus of the pericardium (sinus trans- 
versus pericardii), exists between these vessels in front and the auricle behind. 
This sinus is closed above and below but often to the right and left. The mem- 
brane only partially covers the superior vena cava and the four pulmonary veins, 
TRANSVERSE 
"sinus 
RIGHT 
PULMONARY^ 
VEIN 
PARIETAL/ 
PERICARDIUM 
Fig. 369.-The line of reflection of the serous pericardium. (Modified from Poirier and Charpy.) 
and scarcely covers the inferior cava, as this vessel enters the heart almost directly 
after it has passed through the Diaphragm. A deep blind recess formed by the 
serous pericardium is found behind the heart when that organ is raised up. 
This recess runs backward between the left auricle and the posterior portion of 
the fibrous pericardium, and forms a diverticulum between the heart and the 
oesophagus. This recess is called the oblique sinus. It passes upward between 
the inferior vena cava and the lower left pulmonary vein and terminates between 
the right and left pulmonary veins. The inner surface of the pericardium 
is covered with endothelium, which rests upon a mixture of fibrous and 
elastic tissue, which is smooth and glistening, and secretes a serous fluid (liquor THE PERICARDIUM 
561 
pericardii), which serves to facilitate the movements of the heart. Tn the serous 
layer of the pericardium are many blood-vessels, lymph vessels, and nerves. 
Arteries of the Pericardium.-These are derived from the internal mammary and 
its musculo-phrenic branch, and from the descending thoracic aorta. 
Nerves of the Pericardium.-These are branches from the vagus, the phrenic, 
and the sympathetic. 
The Vestigial Fold of the Pericardium.-Between the left pulmonary artery and 
subjacent pulmonary vein and behind the left extremity of the transverse sinus is 
a triangular fold of the serous pericardium; it is known as the vestigial fold of 
Marshall (ligamentum v. cavce sinistroe). It is formed by the duplicature of the 
serous layer over the remnant of the lower part of the left superior vena cava 
VERTEBRO- 
pericardial 
LIGAM ENTS 
AORTA 
SUPERIOR 
VENA CAVA 
SUPERIOR STERNO- 
PERICARDIAL LIG- 
AMENTS 
ANTERIOR 
•SURFACE OF 
PERICARDIUM 
INFERIOR 
VENA CAVA 
PHRENO- 
PERICARDIAL 
LIGAMENTS 
XIPHO- 
PERICARDIAL 
LIGAMENTS 
Fig. 370.-Ligaments of the pericardium. (Modified from Teutleben.) Right lateral view, showing the right 
vertebra-pericardial ligaments, the right phreno-pericardial, and the superior and inferior sterno-pericardial 
ligaments. (Poirier and Charpy.) 
(y. cava sinistra) or the duct of Cuvier, which, after birth, becomes obliterated, 
and remains as a fibrous band stretching from the left superior intercostal vein 
to the left auricle, where it is continuous with a small vein, the oblique vein of 
Marshall (y. obliqua atrii sinistri [Marshalli]), which opens into the coronary 
sinus and is a remnant of the foetal left superior vena cava. 
Surgical Anatomy.-Aspiration of the pericardium {paracentesis of the pericardium) is occa- 
sionally though seldom performed. It is only to be thought of when pericardial effusion endangers 
life. The operation is very dangerous, because the effusion lifts the heart and pushes it forward, 562 
THE BLOOD-VASCULAR SYSTEM 
and the needle is apt to wound the heart or even enter one of the cavities. There is also danger 
of wounding the internal mammary artery. The operation is never to be thought of in puru- 
lent pericarditis. The safest way to aspirate is to introduce the needle in the fifth interspace 
two inches to the left of the sternum and push it straight backward. 
A better operation, even in a case of serous effusion, and one invariably selected in purulent 
pericarditis, is incision (pericardotomy). A portion of the cartilage of the fifth rib of the left 
side is excised. The pericardium is exposed and is punctured, to learn the nature of the 
contained fluid, and is then incised. By this method the surgeon avoids opening the pleural 
cavity, and can obtain free drainage if pus is found. 
Porter maintains that by "reason of the uncertain and varying relations of the pleura, and 
also of the anterior position of the heart, whenever the pericardial sac is distended with fluid, 
aspiration of the pericardium is a much more dangerous procedure than open incision when 
done by skilled hands." 
.LEFT PHRENIC 
NERVE 
RIGHT PHRENIC. 
NERVE 
.LEFT VAGUS 
NERVE 
LEFT PULMONARY 
'artery 
LEFT BRONCHUS 
LEFT PULMONARY 
VEINS IN ROOT 
OF LUNG 
RIGHT 
PULMONARY' 
VEINS 
LEFT PULMONARY 
VEINS 
PERICARDIUM 
PERICARDIUM 
DIAPHRAGM 
Fig. 371.-Posterior wall of the pericardium, after the removal of the heart, showing the relation of the serous 
pericardium to the great vessels. (From a formalin preparation by Prof. Birmingham.) (Cunningham.) 
THE HEART (COR). 
The heart is a hollow muscular organ of a conical form, placed between the 
lungs, and enclosed in the cavity of the pericardium. 
Position (Fig. 372).-The heart is placed obliquely in the chest: the broad 
attached end, or base (basis cordis), is directed upward, backward, and to the right, 
and corresponds with the dorsal vertebra, from the fifth to the eighth inclusive; the 
apex (apex cordis) is directed downward, forward, and to the left, and corresponds 
to the space between the cartilages of the fifth and sixth ribs, three-quarters of an THE HEART 
563 
inch to the inner side, and an inch and a half below the left nipple, or about three 
and a half inches from the middle line of the sternum. The heart is placed behind 
the sternum, and projects farther into the left than into the right half of the cavity 
of the chest, extending from the median line about three inches in the former 
direction, and only one and a half in the latter; about one-third of the heart lies 
to the right and two-thirds to the left of the mesial plane. The antero-superior 
surface (jacies sternocostalis) is round and convex, directed upward and forward, 
is formed chiefly by the right auricle and ventricle, together with a small part of 
the left ventricle. It lies behind the middle portion of the sternum and the costal 
cartilages of the third, fourth, fifth, and sixth ribs on both sides. On account of 
Fig. 372.-Position of the heart. The pericardium laid open. Adult male. (Poirier and Charpy.) 
the heart's inclination to the left side, only a small part of it lies behind the carti- 
lages of the right ribs. Lying in front of the heart, between it and the anterior 
chest-wall, is the thin anterior margin of the lungs, covered by the pleura. On 
the left side, however, owing to the notch in the anterior margin of the left 
lung (incisura cardiaca), there is a portion of the pericardium lying in contact 
with the Triangularis sterni muscle. This area is called the area of greatest or 
of absolute cardiac dulness or the area of superficial cardiac dulness. The postero- 
inferior surface of the heart (jacies diaphragmatica), which looks downward rather 564 
THE BLOOD-VASCULAR SYSTEM 
than backward, is flattened and rests upon the Diaphragm, and is formed chiefly 
by the left ventricle. The right or lower border is long, thin, and sharp; the left 
or upper border short, but thick and round. 
Size and Weight.-The heart, in the adult, measures five inches in length, 
three inches and a half in breadth in the broadest part, and two inches and a half 
in thickness. The prevalent weight, in the male, varies from ten to twelve ounces; 
in the female, from eight to ten: its proportions to the body being as 1 to 169 in 
males; 1 to 149 in females. The heart continues increasing in weight, and also 
in length, breadth, and thickness, up to an advanced period of life: this increase 
is more marked in men than in women. 
AZYGOS 
VEIN 
LEFT APPENDIX 
AURICULAE 
LEFT AURICULA 
VENTRICULA 
GROOVE 
SULCUS 
TERMINALES 
CORONARY 
SINUS 
- INTERARTICULAR 
SULCUS 
Fig. 373.-Base of the heart in place. The attachments of the pericardium are outlined in red. 
(Poirier and Charpy.) 
OESOPHAGUS 
Capacity of the Cavities of the Heart.-This matter is in dispute. Professor 
Cunningham believes that during life the capacity of the ventricles is nearly iden- 
tical, each holding about four ounces of blood. Each auricle holds a little less 
than four ounces. Stewart maintains that at each heart beat each ventricle 
throws out only eighty-seven grams of blood. Morrant Baker1 says that, "taking 
the mean of various estimates, it may be inferred that each ventricle is able to 
contain four to six ounces of blood.'' 
Fat upon the Heart.-Normally there is a certain amount of fat upon the 
surface of the heart. This begins to appear in the early weeks of life and 
increases in amount as age advances. It is found upon the surface of the 
muscles and along the course of the vessels. Poirier is of the opinion that the 
cardiac fat on the anterior surface of the heart is arranged in three movable 
1 Kirke's Physiology, 10th ed., p. 156. THE HEART 
565 
pads, which act as valves and fill vacant spaces about the heart created during 
the cardiac contractions.1 
Component Parts.-The heart is subdivided by a muscular septum into two 
lateral halves, which are named respectively the right or pulmonary heart and the 
left or systemic heart; and a transverse constriction subdivides each half of the 
organ into two cavities, the upper cavity on each side being called the auricle, 
the lower the ventricle. The course of the blood through the heart cavities and 
blood-vessels has already been described (page 555). 
The division of the heart into four cavities is indicated by grooves upon its sur- 
face. The groove separating the auricles from the ventricles is called the auriculo- 
ventricular groove (sulcus coronarius). It is deficient, in front, where it is crossed 
by the root of the pulmonary artery. It contains the trunks of the nutrient vessels 
of the heart. The auricular portion occupies the base of the heart, and is sub- 
divided into two cavities by a median septum. The two ventricles are also sepa- 
rated into a right and left by two furrows, the interventricular grooves (sulci longi- 
tudinales), which are situated one on the anterior (sulcus longitudinalis anterior), 
the other on the posterior (sulcus longitudinalis posterior) surface; these extend 
from the base of the ventricular portion to near the apex of the organ; the former 
being situated nearer to the left border of the heart, and the latter to the right. 
It follows, therefore, that the right ventricle forms the greater portion of the 
anterior surface of the heart, and the left ventricle more of its posterior surface. 
The internal surface of the heart is lined with endocardium. 
The auricular portion occupies the base of the heart and is subdivided into two 
cavities or auricles (atria) by a septum. As before stated, this portion of the heart 
corresponds to the middle segment of the dorsal spine. Its form is quadrilateral 
in shape, and has two processes extending upward from its two upper angles, 
called the auricular appendices (appendices auricula;), between which are found 
the aorta and the pulmonary artery. The greater part of the base of the heart 
is formed by the left auricle. Its boundaries are, above, the pulmonary artery; 
below, the coronary sinus; on the left it is bounded by the left superior and 
inferior pulmonary veins, while on the right side it is limited by the sulcus 
terminalis. The latter corresponds to a ridge in the interior of the auricle, 
called the crista terminalis. Running vertically on this surface, just to the 
left of the openings of the two venae cavae, is the interauricular furrow, which 
exactly indicates the proportion of the base of the heart formed by each 
auricle. 
Each of the cavities should now be separately examined. 
The Right Auricle2 (atrium dextrum) is a little larger than the left, its walls 
somewhat thinner, measuring about one line. It consists of two parts: a principal 
cavity, the sinus venosus, situated posteriorly, and an anterior, smaller portion, 
the appendix auriculae. The right auricle is separated from the left auricle by 
the interauricular septum (septum afriorum). Part of this septum is muscular; 
part is composed of connective tissue. 
The sinus venosus (sinus venarum) is the large quadrangular cavity, placed 
between the two venae cavae; its walls are extremely thin; it is connected below 
with the right ventricle, and internally with the left auricle, being free in the 
rest of its extent. It is derived from a portion of the sinus reuniens of the 
foetal heart. 
The right auricular appendix (auricula dextro), so-called from its fancied resem- 
blance to a dog's ear, is a small conical muscular pouch, the margins of which 
present a dentated edge. It projects from the sinus forward and to the left 
side, overlapping the root of the aorta. 
1 L'appariel sero-graisseux. La Presse M6dicale, December 7, 1904. 
2 In the new nomenclature the auricle is called the atrium, and auricular appendix is called the auricle. 566 
THE BLOOD - VASCULAR SYSTEM 
To examine the interior of the right auricle, an incision should be made along its right border, 
from the entrance of the superior vena cava to that of the inferior. A second cut is to be made 
from the centre of this first incision to the tip of the auricular appendix, and the flaps raised. 
The internal surface of the right auricle is smooth, except in the appendix 
and adjacent part of the anterior wall of the sinus venosus, where the muscular 
wall is thrown into parallel ridges resembling the teeth of a comb and hence 
named the musculi pectinati. These end behind on a vertical smooth ridge, the 
Foramina, 
The besii 
Tubercle 
of Lower.. 
Bristle passed through 
Right Auricula- Ventricular opening. 
Fig. 374.-The right auricle and ventricle laid open, the anterior walls of both being removed. 
crista terminalis of His, the position of which is indicated on the surface of the 
distended auricle by a furrow, the sulcus terminalis of His. The sulcus terminalis 
passes from in front of the superior vena cava to the left of the inferior vena cava. 
It represents the line of fusion of the sinus venosus of the embryo with the primi- 
tive auricle proper. 
The right auricle presents the following parts for examination: 
Superior cava. 
Inferior cava. 
Coronary sinus. 
Foramini Thebesii. 
Auriculo-ventricular. 
Eustachian. 
Coronary. 
Openings 
Valves 
Fossa ovalis. 
Annulus ovalis. 
Tuberculum Loweri. 
Musculi pectinati. 
The superior vena cava returns the blood from the upper half of the body, and 
opens into the upper and back part of the auricle, the direction of its orifice being 
downward and forward. The superior vena cava does not possess valves. 
The inferior vena cava, larger than the superior, returns the blood from the 
lower half of the body, and opens into the lowest part of the auricle near the THE HEART 
567 
septum, the direction of its orifice being upward and inward. The direction of 
a current of blood through the superior vena cava would consequently be toward 
the auriculo-ventricular orifice, whilst the direction of the blood through the 
inferior cava would be toward the auricular septum. This is the normal direction 
of the two currents in fetal life. The inferior vena cava does not possess valves 
until its termination at the right auricle. 
The coronary sinus (sinus coronarius) opens into the auricle, between the inferior 
vena cava and the auricido-ventricular opening. It returns the blood from the 
substance of the heart, and is protected by a semicircular fold of the lining mem- 
brane of the auricle, the coronary valve or valve of Thebesius. The sinus, before 
entering the auricle, is considerably dilated-nearly to the size of the end of the 
little finger. Its wall is partly muscular, and at its junction with the great coronary 
vein it is somewhat constricted and is furnished with a valve consisting of two 
unequal segments. 
The foramini Thebesii (foramina venarum minimarum) are numerous minute 
fossae or apertures on various parts of the inner surface of the auricle. Many of 
these foramina have at their points the minute openings of small veins (vence 
minimoe cordis). They return the blood directly from the muscular substance 
of the heart. Some of these foramina are minute depressions in the walls of the 
heart, presenting a closed extremity. 
The right auriculo-ventricular opening or the tricuspid orifice (ostium venosum 
dextrum) is the large oval aperture of communication between the right auricle 
and the ventricle, to be presently described. 
The Eustachian valve (valvida vence cavoe inferioris [Eustachii]) is situated 
between the anterior margin of the inferior vena cava and the auriculo-ventricular 
orifice. It is semilunar in form, its convex margin being attached to the wall 
of the vein; its concave margin, which is free, terminating in two cornua, of 
which the left is attached to the anterior edge of the annulus ovalis, the right 
being lost on the wall of the auricle. The valve is formed by a duplicature of the 
lining membrane of the auricle and contains a few muscular fibres. 
In the joetus this valve is of large size, and serves to direct the blood from the 
inferior vena cava, through the foramen ovale, into the left auricle. 
In the adult it is occasionally large, and may assist in preventing the reflux 
of blood into the inferior vena cava; more commonly it is small, and its free 
margin presents a cribriform or filamentous appearance; occasionally it is alto- 
gether wanting. 
The coronary valve or valve of Thebesius (valvuloe sinus coronarii [Thebesii]) 
is a semicircular fold of the lining membrane of the auricle, protecting 
the orifice of the coronary sinus. It prevents the regurgitation of blood 
into the sinus during the contraction of the auricle. This valve is occasionally 
double. 
The fossa ovalis is an oval depression corresponding to the situation of the 
foramen ovale in the fetus. It is situated at the lower part of the septum atriorum, 
above and to the left of the orifice of the inferior vena cava. In fetal life an 
opening, the foramen ovale, exists at this point between the two auricles; almost 
immediately after birth the valve-like edge is pressed down by the increased 
pressure in the left auricle and by the tenth day it passes to the annulus and 
closes the opening. 
'The annulus ovalis (limbus fossae ovalis [F/ew^enu]) is a prominent oval margin 
which surrounds anteriorly and superiorly the fossa ovalis. It is most distinct 
above and at the sides; below, it is deficient. A small slit-like valvular opening 
is occasionally found, at the upper margin of the fossa ovalis, which leads 
upward beneath the annulus into the left auricle, and is the remains of the 
aperture between the two auricles in the fetus. 568 
THE BLOOD-VASCULAR SYSTEM 
The tubercle of Lower (tuberculum intervenosum [Loweri]) is a small projection 
on the interauricular septum between the fossa ovalis and the opening of the 
superior vena cava. It is most distinct in the hearts of quadrupeds; in man it 
is scarcely visible. It was supposed by Lower to direct the blood from the 
superior cava toward the auriculo-ventricular opening. 
The Left Auricle (atrium sinistrum) is rather smaller than the right; its walls 
are thicker, measuring about one line and a half; and it consists, like the right, 
of two parts, a principal cavity, or sinus, and an appendix auriculae. 
The sinus is cuboidal in form, and concealed in front by the pulmonary artery 
and aorta; internally, it is separated from the right auricle by the septum auricu- 
larum (septum atriorum); behind, it receives on each side two pulmonary veins, 
being free in the rest of its extent. 
The left auricular appendix (auricula sinistra) is somewhat constricted at its 
junction with the auricle; it is longer, narrower, and more curved than that of 
the right side, and its margins are more deeply indented, presenting a kind of 
foliated appearance. Its direction is forward and toward the right side, over- 
lapping the root of the pulmonary artery. 
Within the auricle the following parts present themselves for examination: 
The openings of the four pulmonary veins. 
Auriculo-ventricular opening. 
Musculi pectinati. 
Foramina Thebesii. 
The pulmonary veins, four in number, open, two into the right and two into 
the left side of the auricle. The two left veins frequently terminate by a common 
opening. They are not provided with valves. 
The auriculo-ventricular opening or mitral orifice (ostium venosum ventriculi 
sinistri) is the large oval aperture of communication between the left auricle 
and the left ventricle. It is rather smaller than the corresponding opening on 
the opposite side (see note, page 569). 
The musculi pectinati are fewer in number and smaller than on the right side; 
they are confined to the inner surface of the auricular appendix. 
On the inner surface of the septum atriorum may be seen a lunated impres- 
sion bounded below by a crescentic ridge the concavity of which is turned upward. 
The depression is just above the fossa ovalis in the right auricle. The inner sur- 
face of the auricle shows foramini Thebesii and venae minimis cordis. 
To examine the interior of the left ventricle, make an incision a little to the left of the anterior 
interventricular groove from the base to the apex of the heart, and carry it up from thence, 
a little to the left of the posterior interventricular groove, nearly as far as the auriculo-ventricular 
groove. 
The ventricular portion of the heart is conical in shape with its base extending 
backward and upward and fitting against the atrii of the auricles. Its apex 
constitutes the apex of the heart (apex cordis) and extends to the fifth intercostal 
space three and a quarter inches to the left of the middle line. The ventricles 
are thick and muscular and have an antero-superior surface (fades sternalis) and 
a postero-inferior surface (fades diaphragmatici) and two borders, a right and a 
left border. The antero-superior surface is composed mainly of the right ven- 
tricle; coursing on this surface, nearer the left border than the right from the 
auriculo-ventricular groove to the apex, is the anterior interventricular groove 
(sulcus longitudinalis anterior). The inferior surface rests on the diaphragm and 
is chiefly made by the left ventricle; it is also traversed by a groove called the 
inferior or posterior interventricular groove (sulcus longitudinalis posterior). 'The 
two grooves meet in a groove (incisura apicis cordis) at the right side of the THE HEART 
569 
apex of the heart. Of the two borders of the ventricular portion the right is 
sharp and thin (margo acutus) and is a continuation of the sulcus terminalis of 
the base of the heart. It extends from right to left. The left border is thick 
and rounded (margo obtusus). The base of the ventricles is perforated by four 
large openings, namely, the aorta, the pulmonary artery, the right and left 
auriculo-ventricular openings. 
The Right Ventricle (ventriculus dexter) is triangular in form, and extends 
from the right auricle to near the apex of the heart. Its antero-superior surface 
is rounded and convex, and forms the larger part of the front of the heart. Its 
inferior surface is flattened, rests upon the Diaphragm, and forms only a small 
part of the back of the heart. Its posterior wall is formed by the partition between 
the two ventricles, the interventricular septum (septum ventriculorum), so that a 
transverse section of the cavity presents a semilunar outline. The surface of 
the septum is convex and bulges into the cavity of the right ventricle. The 
upper and inner angle of the ventricle is prolonged into a conical pouch, the 
infundibulum (conus arteriosus), from which the pulmonary artery arises. The 
balance of the ventricle, the body, is the portion into which the auriculo- 
ventricular orifice opens. The conus arteriosus is marked off from the body of 
the ventricle by a muscular projection (crista supraventricularis). The walls of 
the right ventricle are thinner than those of the left, the proportion between them 
being as 1 to 3. The wall is thickest at the base, and gradually becomes thinner 
toward the apex. 
To examine the interior of the right ventricle, its anterior wall should be turned downward 
and to the right in the form of a triangular flap. This is accomplished by making two incisions: 
(1) from the pulmonary artery to the apex of the ventricle parallel to, but a little to the right 
of, the anterior interventricular furrow; (2) another, starting from the upper extremity of the 
first and carried outward parallel to, but a little below, the auriculo-ventricular furrow, care 
being taken not to injure the auriculo-ventricular valve. 
The following parts present themselves for examination: 
Openings 
Auriculo-ventricular. 
Opening of the pulmonary artery. 
Tricuspid. 
Semilunar. 
Valves 
And a muscular and tendinous apparatus connected with the tricuspid valve: 
Columnse carneae. Chordae tendineae. 
The right auriculo-ventricular opening or the tricuspid orifice (ostium venosum ven- 
triculi dextri) is the large oval aperture of communication between the auricle and 
ventricle. It is situated at the base of the ventricle, near the right border of 
the heart. It is about an inch and a half in diameter,1 oval from side to side, 
surrounded by a fibrous ring and covered by the lining membrane of the heart; 
it is considerably larger than the corresponding aperture on the left side, being 
sufficient to admit the ends of four fingers. It is guarded by the tricuspid 
valve. 
The opening of the pulmonary artery (ostium arteriosum) is circular in form, 
and is situated at the summit of the conus arteriosus, close to the septum ven- 
triculorum. It is placed above and on the left side of the auriculo-ventricular 
1 In the Pathological Transactions, vol. vi. p. 119, Dr. Peacock has given some careful researches upon the 
weight and dimensions of the heart in health and disease. He states, as a result of his investigations, that 
in the healthy adult heart the right auriculo-ventricular aperture has a mean circumference of 54.4 lines, or 
420/24 inches; the left auriculo-ventricular aperture a mean circumference of 44.3 lines, or 34/»4 inches; the pulmonic 
orifice of 40 lines, or 3'3/aj inches; and the aortic orifice of 35.5 lines, or 32-/o4 inches; but the dimensions of the 
orifices varied greatly in different cases, the right auriculo-ventricular aperture having a range of from 40 to 50 
lines, and the others in the same proportion.-Ed. of 15th English edition. 570 
THE BLOOD-VASCULAR SYSTEM 
opening, upon the anterior aspect of the heart. Its orifice is guarded by the 
pulmonary semilunar valves. 
The tricuspid valve (valvula tricuspidalis) consists of three segments or cusps 
(cuspides) of a triangular or trapezoidal shape, each formed by a duplicature of 
the lining membrane of the heart, strengthened by a layer of fibrous tissue, which 
contains, according to Kiirschner and Senac, muscular fibres. These segments 
are connected by their bases to the oval fibrous ring surrounding the auriculo- 
ventricular orifice (annulus fibrosus dexter), and by their sides with one another, 
so as to form a continuous annular membrane, which is attached round the 
margin of the auriculo-ventricular opening, their free margins and ventricular 
surfaces affording attachment to a number of delicate tendinous cords, the 
chordae tendineae. The largest and most movable segment is placed toward 
the left side of the auriculo-ventricular opening, and is interposed between that 
opening and the infundibulum; hence it is called the left or infundibular cusp 
(cuspis medialis). Another segment corresponds to the right part of the front 
of the ventricle, the right or marginal cusp (cuspis anterior), and a third to its 
posterior wall, the posterior or septal cusp (cuspis posterior). The central part of 
each segment is thick and strong: the lateral margins are thin and translucent. 
The chordae tendineae are connected with the adjacent margins of the principal 
segments of the valve, and are further attached to each segment in the following 
manner: 1. Three or four reach the attached margin of each segment, where 
they are continuous with the auriculo-ventricular tendinous ring. 2. Others, four 
to six in number, are attached to the central thickened part of each segment. 3. 
The most numerous and finest are connected with the marginal portion of each 
segment. 
The columnae cameae (trabeculae carnece) are the rounded muscular columns 
which project from nearly the whole of the inner surface of the ventricle, except- 
ing near the opening of the pulmonary artery, where the wall is smooth. They 
may be classified, according to their mode of connection with the ventricle, into 
three sets. The first set merely forms prominent ridges on the inner surface of 
the ventricle, being attached by their entire length on one side, as well as by 
their extremities. The second set are attached by their two extremities, but are 
free in the rest of their extent; while the third set (musculi papillares) are attached 
by one extremity to the wall of the heart, the opposite extremity giving attach- 
ment to the chordae tendineae. There are two papillary muscles, the anterior and 
the posterior: of these, the anterior is the larger; its chordae tendinae are connected 
with the right and left segments of the tricuspid valve. The posterior is not 
always single, but sometimes consists of two or three muscular columns; its 
chordae tendineae are connected with the posterior and the right segments of the 
tricuspid valve. In addition to these, some few chordae may be seen springing 
directly from the ventricular septum, or from small eminences on it, and passing 
to the left and posterior segments. A fleshy band, well marked in the ox and 
some other animals, is frequently seen passing from the base of the anterior 
papillary muscle to the interventricular septum. From its attachments it may 
assist in preventing overdistention of the auricle, and so has been named the 
moderator band. 
The right auriculo-ventricular orifice allows the blood to pass freely from the 
right auricle into the right ventricle, and it will be noted that the surface of the 
tricuspid valve next the blood-current is quite smooth. When the right ventricle 
contracts to force the blood into the pulmonary artery, the segments of the tri- 
cuspid valve come together and close the auriculo-ventricular opening, and so 
prevent the blood from passing back into the auricle. The papillary muscles 
and chordae tendineae moor the segments of the valve and prevent their being 
forced through into the auricle by the weight of blood behind them. THE HEART 
571 
The semilunar valves (valvula? semilunares a. pulmonalis), three in number,1 
guard the orifice of the pulmonary artery. They consist of three semicircular 
folds: two of which are anterior and one of which is posterior. They are formed 
by duplicatures of the lining membrane of the ventricle, strengthened by fibrous 
tissue. They are attached, by their convex margins, to the wall of the artery, at its 
junction with the ventricle, the straight border being free, and directed upward in 
the lumen of the vessel. The free margin of each is somewhat thicker than the rest 
of the valve, is strengthened by a bundle of tendinous fibres, and presents, at its 
middle, a small projecting thickened nodule, consisting of bundles of interlacing 
connective-tissue fibres with branched connective-tissue cells and some few elastic 
fibres. Such a nodule is called the corpus Arantii or body of Arangi (nodulus valvula? 
semilunaris [Arantii]). From this nodule tendinous fibres radiate through the valve 
to its attached margin, and these fibres form a constituent part of its substance 
throughout its whole extent, excepting two narrow lunated portions, the lunulae 
(lunulae valvularum semilunarium), placed one on each side of the nodule imme- 
diately adjoining tlje free margin; here the valve is thin, and formed merely by the 
lining membrane. During the passage of the blood along the pulmonary artery 
these valves are opened, and the course of the blood along the tube is uninter- 
rupted; but during the ventricular diastole, when the current of blood along the 
pulmonary artery is checked and partly thrown back by its elastic walls, these 
valves become immediately expanded, and effectually close the entrance of the 
tube. When the valves are closed, the lunated portions of each are brought into 
contact with one another by their opposed surfaces, the three corpora Arantii fill- 
ing up the small triangular space that would be otherwise left by the approxima- 
tion of the three semilunar valves. 
Between the semilunar valves and the commencement of the pulmonary artery 
are three pouches or dilatations, one behind each valve. These are the pulmonary 
sinuses of Valsalva. Similar sinuses exist between the semilunar valves and the 
commencement of the aorta; they are larger than the pulmonary sinuses. The 
blood, in its regurgitation toward the heart, finds its way into these sinuses, and 
so shuts down the valve-flaps. 
In order to examine the interior of the left auricle, make an incision on the posterior surface 
of the auricle from the pulmonary veins on one side to those on the other, the incision being 
carried a little way into the vessels. Make another incision from the middle of the horizontal 
one to the appendix. 
The Left Ventricle (ventriculus sinister} is longer and more conical in shape 
than the right ventricle, and on transverse section its cavity presents an oval or 
nearly circular outline. It forms a small part of the anterior surface of the heart 
and a considerable part of its posterior surface. It also forms the apex of the 
heart by its projection beyond the right ventricle. Its walls are much thicker 
than those of the right side, the proportion being as 3 to 1. They are thickest oppo- 
site the widest part of the ventricle, becoming gradually thinner toward the base, 
and also toward the apex, which is the thinnest part. 
The following parts present themselves for examination: 
Openings 
Auriculo-ventricular. 
Aortic. 
Valves 
Mitral. 
Semilunar. 
Chord® tendine®. 
Column® carne®. 
The left auriculo-ventricular opening or the mitral orifice (ostium venosum ven- 
triculi sinistri) is placed below and to the left of the aortic orifice. It is a little 
1 The pulmonary semilunar valves have been found to be two in number instead of three (Dr. Hand, of St. 
Paul, Minn., in North Western Med. and Surg. Journ., July, 1873), and the same variety is more frequently 
noticed in the aortic semilunar valves.-Ed. of 15th English edition. 572 
THE BLOOD-VASCULAR SYSTEM 
smaller than the corresponding aperture of the opposite side, admitting only two 
fingers; but, like it, is broader in the transverse than in the antero-posterior 
diameter. Its right, posterior, and left sides are surrounded by a dense horseshoe- 
shaped fibrous ring (annulus fibrosus sinister). The orifice is guarded by the 
mitral valves, which are covered with endocardium. 
The aortic opening (ostium arteriosum) is a circular aperture, in front and to 
the right side of the auriculo-ventricular opening, from which it is separated by 
one of the segments of the mitral valve. Its orifice is guarded by the semilunar 
valves. The portion of the ventricle immediately below the aortic orifice is often 
termed the aortic vestibule of Sibson. It possesses fibrous instead of muscular 
walls, and so does not collapse during the ventricular diastole; it thus gives space 
for the segments of the aortic valve during its closure. 
Bristle passed through left 
auriculo-ventricular opening. 
Passed through aortic opening. 
Fig. 375.-The left auricle and ventricle laid open, the posterior walls of both being removed. 
The mitral or bicuspid valve (valvula bicuspidalis) is attached to the circumfer- 
ence of the auriculo-ventricular orifice in the same way that the tricuspid valve is 
on the opposite side. It is formed by a duplicature of the lining membrane, 
strengthened by fibrous tissue, and contains a few muscular fibres. It is larger 
in size, thicker, and altogether stronger than the tricuspid, and consists of two 
segments of unequal size. The larger segment, the anterior or aortic cusp (cuspis 
anterior}, is placed in front and to the right between the auriculo-ventricular and 
aortic orifices, the smaller, the posterior or marginal cusp (cuspis posterior), is 
placed to the left and behind the opening, close to the wall of the ventricle. Two 
smaller segments are usually found at the angles of junction of the larger. The 
mitral valve-flaps are furnished with chordae tendineae, the mode of attachment 
of which is precisely similar to those on the right side; but they are thicker, 
stronger, and less numerous. 
The aortic semilunar valves (valvuloe semilunares aorfcc) surround the orifice of 
the aorta; one is posterior (valvula semilunaris posterior)', one right (valvula TILE HEART 
573 
semilunaris dextra), and one left (valvula semilunaris sinistra): they are similar in 
structure and in their mode of attachment to those of the pulmonary artery. They 
are, however, larger, thicker, and stronger than those of the right side; the lunulae 
are more distinct and the corpora Arantii larger and more prominent. Opposite 
each segment the wall of the aorta presents a slight dilatation or bulging, the 
sinus of Valsalva. 
The columnae cameae admit of a subdivision into three sets, like those upon 
the right side; but they are smaller, more numerous, and present a dense inter- 
lacement, especially at the apex, and upon the posterior wall. Those attached by 
one extremity only, the musculi papillares, are two in number, being connected 
Pulmonary 
artery. 
Musculi 
pectinati. 
Coronary 
sinus. 
Fig. 376.-Section of the heart, showing the interventricular septum. 
one to the anterior, the other to the posterior wall; they are of large size, and 
terminate by free rounded extremities, from which the chordae tendineae arise. 
The septum between the two ventricles (septum ventri culorum) is thick and 
muscular, especially below (Fig. 376). At its upper part it suddenly tapers off, 
becomes destitute of muscular fibres, and consists only of fibrous tissue, covered 
by two layers of endocardium; and on the right side also covered, during dias- 
tole, by one of the flaps of the tricuspid valve. This upper portion is termed 
the undefended or membranous part of the septum (septum membranaceum ven- 
triculorum), and is continued upward and forms the septum between the 
aortic vestibule and the right auricle. It is derived from the lower part of 
the aortic septum of the fetus, and an abnormal communication may exist at 
this part, owing to defective development of this septum. THE BLOOD-VASCULAR SYSTEM 
574 
Structure of the Heart.-The heart is a hollow muscular organ and its walls 
are divisible into three layers: the endocardium, myocardium, and visceral layer of 
the pericardium (page 560). 
The Endocardium is the lining membrane of the heart. It is composed of 
endothelial cells resting upon a connective-tissue membrane which contains 
unstriated muscle cells and elastic tissue. This connective-tissue membrane of 
the endocardium is attached to the myocardium by loose elastic tissue. The endo- 
thelial layer of the endocardium is continuous with the endothelial coat of the 
blood-vessels. The endocardium is more opaque on the left than on the right 
side of the heart, thicker in the auricles than in the ventricles, and thickest in 
the left auricle. It is thin on the musculi pectinati and on the columnse carnete, 
but thicker on the smooth parts of the auricular and ventricular walls and on the 
tips of the musculi papillares. 
The Fibrous Rings (annuli fibrosi) surround the auriculo-ventricular and arterial 
orifices; they are stronger upon the left than on the right side of the heart. The 
auriculo-ventricular rings serve for the attachment of the muscular fibres of the 
auricles and ventricles, and also for the mitral and tricuspid valves; the ring on the 
RIGHT AURICULO- 
VENTRICULAR ORIFICE 
PULMONARY 
ORIFICE ' 
AORTIC 
ORIFICE 
LEFT 
NODULE ' 
LEFT AURICULO- 
VENTRICULAR ORIFICE 
RIGHT 
NODULE 
left side is closely connected by its right margin with the aortic arterial ring. Be- 
tween these and the right auriculo-ventricular ring is a mass of fibrous tissue, and in 
some of the larger animals, as the ox and elephant, a nodule of bone, the os cordis. 
The fibrous rings surrounding the arterial orifices serve for the attachment of 
the great vessels and semilunar valves. Each ring receives, by its ventricular 
margin, the attachment of the muscular fibres of the ventricles; its opposite margin 
presents three deep semicircular notches, within which the middle coat of the 
artery (which presents three convex semicircular segments) is firmly fixed, the 
attachment of the artery to its fibrous ring being strengthened bv the thin cellular 
coat and serous membrane externally and by the endocardium within. It is 
opposite the margins of these semicircular notches, in the arterial rings, that the 
endocardium by its reduplication forms the semilunar valves, the fibrous structure 
of the ring being continued into each of the segments of the valve at this part. 
The middle coat of the artery in this situation is thin, and the sides of the vessel are 
dilated to form the sinuses of Valsalva. 
The Myocardium is composed of muscle fibres which differ from ordinary striated 
muscle fibres, and are called cardiac fibres. Between individual fibres and be- 
tween bundles of fibres is connective tissue carrying capillaries. 
Fig. 377.-Fibrous zones at the base of the ventricles. (Poirier and Charpy.) THE HEART 
575 
The Muscular Structure of the heart consists of bands of fibres which present 
an exceedingly intricate interlacement. They are of a deep red color and marked 
with transverse striae. 
The muscular fibres of the heart admit of a subdivision into two groups, those 
of the auricles and those of the ventricles, which are quite independent of one 
another. 
Fibres of the Auricles (Fig. 378).-These are disposed in two layers-a 
superficial layer common to both cavities, and a deep layer proper to each. The 
superficial fibres are more distinct on the anterior surface of the auricles, across 
the bases of which they run in a transverse direction, forming a thin but incomplete 
layer. Some of these fibres pass into the septum atriorum. The internal or deep 
fibres proper to each auricle consist of two sets, looped and annular fibres. The 
looped fibres pass upward over each auricle, being attached by two extremities 
to the corresponding auriculo-ventricular rings in front and behind. The annular 
fibres surround the whole extent of the auricular appendices, and are continued 
upon the walls of the veme cava? and coronary sinus on the right side, and upon 
the pulmonary veins on the left side, at their connection with the heart. In the 
appendices they interlace with the longitudinal fibres. 
Fig. 378.-The arrangement of the muscles of the auricles. (Poirier and Charpy.) 
Fibres of the Ventricles.-These are arranged in an exceedingly complex 
manner, and the accounts given by various anatomists differ considerably. This 
is probably due partly to the fact that the various layers of muscular fibres of 
which the heart is said to be composed are not independent, but their fibres are 
interlaced to a considerable extent, and therefore any separation into layers must 
be to a great extent artificial; and also partly to the fact, pointed out by Henle, 
that there are varieties in the arrangement due to individual differences. If the 
epicardium and the subjacent fat are removed from a heart which has been sub- 
jected to prolonged boiling, so as to dissolve the connective tissues, the superficial 
fibres of the ventricles will be exposed. They will be seen to commence at the base 
of the heart, where they are attached to the tendinous rings around the orifices, 
and to pass obliquely downward toward the apex, with a direction from right to 
left. At the apex the fibres turn suddenly inward into the interior of the ventricle, 
forming what is called the vortex (Fig. 379). On the back of the heart it will be 
seen that the fibres pass continuously from one ventricle to the other over the inter- 
ventricular groove; and the same thing will be noticed on the front of the heart at 
the upper and lower end of the anterior interventricular groove, but in the middle 
portion of this groove the fibres passing from one ventricle to the other are inter- 576 
THE BLOOD-VASCULAR SYSTEM 
rupted by fibres emerging from the septum along the groove; many of the super- 
ficial fibres pass in also at this groove to the septum. The vortex is produced, 
as stated above, by the sudden turning 
inward of the superficial fibres in a 
peculiar spiral manner into the deepest 
portion of the wall of the ventricle. 
Those fibres which descended on the 
posterior surface of the heart enter the 
left ventricle at the vortex, and, ascend- 
ing, form the posterior part of the inner 
layer of muscular fibres lining this 
cavity and the right (posterior) mus- 
culus papillaris; those fibres which 
descend on the front of the heart to 
reach the apex also pass, at the vortex, 
into the interior of the ventricle, where 
they form the remainder of the inner- 
most layer of the ventricle and the left 
(anterior) musculus papillaris. The 
fibres forming the inner layer of the wall of the ventricle ascend to be attached 
to the fibrous rings around the orifices. 
By dissection these superficial fibres may be removed as a thin stratum, and it 
will then be found that the ventricles are made up of oblique fibres (Fig. 380), super- 
Fig. 379.-The muscular arrangement of the apex 
of the heart. (Poirier and Charpy.) 
Fig. 380.-The muscular arrangement of the ventricle. (Poirier and Charpy.) 
imposed in layers one on the top of another, and assuming gradually a less oblique 
direction as they pass to the middle of the thickness of the ventricular wall, so that THE HEART 
577 
in the centre of the wall the fibres are transverse. Internal to this central transverse 
layer the fibres become oblique again, but in the opposite direction to the external 
ones. This division into distinct layers is, however, to a great extent artificial, as the 
fibres pass across from one layer to another, and have therefore to be divided in 
the dissection, and the change in the direction of the fibres is very gradual. These 
oblique fibres commence above at the fibrous rings at the base of the heart, and, 
descending toward the apex, they enter the septum near its lower end. In the 
septum the fibres which form the left ventricle may be traced in three directions: 
1. Some pass upward to be attached to the central mass of fibrous tissue. 2. 
Others pass through the septum to become continuous with the fibres of the right 
ventricle. 3. The remainder pass through the septum to encircle the ventricle 
as annular fibres. Of the fibres of the right ventricle, some on entering the septum 
pass upward to be attached to the central mass of fibrous tissue; some, entering 
the septum from behind, pass forward to become continuous with the fibres on 
the anterior surface of the left ventricle; and others, entering in front, pass back- 
ward to join the fibres on the posterior wall of the left ventricle. The septum 
therefore consists of three varieties of fibres-viz., annular fibres, special to the left 
ventricle; ascending fibres, derived from both ventricles and ascending through 
the septum to the central fibro-cartilage; and decussating fibres, derived from the 
anterior wall of one ventricle and passing to the posterior wall of the other ven- 
tricle, or from the posterior wall of the right ventricle and passing to the anterior 
wall of the left. In addition to these fibres there are a considerable number 
which appear to encircle both ventricles and which pass across the septum without 
turning into it. 
Vessels and Nerves.-The arteries supplying the heart are the right and left 
coronary from the aorta. Branches from the coronary vessels supply the mus- 
cular structure, the subendocardial, and the subepicardial tissue. There are no 
vessels in the endocardium. The valves contain no vessels unless they contain 
muscle, in which case minute vessels enter them. There are numerous capillary 
networks about the muscular fibres. 
The veins accompany the arteries. They are: the anterior or great, the posterior, 
the left, and the anterior cardiac veins, the right or small, and the left or great, 
coronary sinuses. The coronary sinus receives most of the veins of the heart and 
empties into the right auricle. Some few small veins open directly into the right 
and left auricles and into the ventricles. They are the vense minimse cordis. The 
oblique vein of the left auricle is known as the oblique vein of Marshall. 
The lymphatics are arranged in two networks: one in the muscle beneath the 
endocardium, another in the muscle beneath the epicardium. The deep empties 
into the superficial network, the anterior collecting trunks from the subepicardial 
network pass to the tracheo-bronchial glands. The posterior collecting trunk 
terminates in the.same group of glands.1 
The nerves are derived from the superficial and deep cardiac plexuses, and from 
these plexuses obtain fibres of the pneumogastric, spinal accessory, and sympa- 
thetic. The superficial cardiac plexus lies under the arch of the aorta. The 
deep cardiac plexus is in front of the tracheal bifurcation. The nerves from the 
plexuses are freely distributed both on the surface and in the substance of the 
heart, the separate filaments being furnished with small ganglia. 
Surface Form.-In order to show the extent of the heart in relation to the front of the chest, 
draw a line from the lower border of the second left costal cartilage, one inch from the sternum, 
to the upper border of the third right costal cartilage, half an inch from the sternum. This 
represents the base-line or upper limit of the organ. Take a point an inch and a half below 
and three-quarters of an inch internal to the left nipple-that is, about three and a half inches 
to the left of the median line of the body. This represents the apex of the heart. Draw a line 
1 The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. 578 
THE BLOOD-VASCULAR SYSTEM 
from this apex-point, with a slight convexity downward, to the junction of the seventh right 
costal cartilage to the sternum. This represents the lower limit of the heart. Join the right 
extremity of the first line-that is, the base-line-with the right extremity of this line-that is, 
to the seventh right chondro-sternal joint-with a slight curve outward, so that it projects about 
an inch and a half from the middle line of the sternum. Lastly, join the left extremity of the 
base-line and the apex-point by a line curved slightly to the left. 
The position of the various orifices is as follows-viz., the pulmonary orifice is situated in 
the upper angle formed by the articulation of the third left costal cartilage with the sternum; 
the aortic orifice is a little below and internal to this, behind the left border of the sternum, 
close to the articulation of the third left costal cartilage to this bone. The left auriculo-ventric- 
ular opening is behind the sternum, rather to the left of the median line, and opposite the fourth 
costal cartilages. The right auriculo-ventricular opening is a little lower, opposite the fourth 
interspace and in the middle line of the body (Fig. 3G6). 
A portion of the area of the heart thus mapped out is uncovered by lung, and therefore 
gives a dull note on percussion; the remainder, being overlapped by the lung, gives a more or 
less resonant note. The former is known as the area of superficial cardiac dulness; the latter 
as the area of deep cardiac dulness. The area of superficial cardiac dulness is included between 
a line drawn from the centre of the sternum, on a level with the fourth costal cartilages, to the 
apex of the heart and a line drawn from the same point down the lower third of the middle line 
of the sternum. Below, this area merges into the dulness which corresponds to the liver. Dr. 
McClellan states that the area of superficial cardiac dulness may be mapped out " by draw- 
ing a line from the middle of the sternum opposite the fourth left costal cartilage to the point 
of junction of the fifth rib and its cartilage, and from this point horizontally back to the mid- 
sternal line." 
Surgical Anatomy.-Wounds of the heart are often immediately fatal, but not necessarily 
so. They may be non-penetrating, when death may occur from hemorrhage, if one of the coro- 
nary vessels has been wounded, or subsequently from pericarditis; or, on the other hand, the 
patient may recover. Even a penetrating wound is not necessarily fatal, if the wound is a small 
one. An attempt should be made to save the patient by means of a surgical operation. A 
trap-door flap comprising the whole thickness of the thoracic wall should be made. The hinges 
of the trap-door are the rib cartilages. The pericardium is exposed and opened freely, clots are 
removed, the wound in the heart is sought for, and when discovered is sutured. In a pene- 
trating wound the sutures include the whole thickness of the heart, except the endocardium. 
Interrupted sutures should be used, and each one had better be tied during diastole. A number 
of successful operations of this character have been performed. 
Peculiarities in the Vascular System of the Foetus (Fig. 382). 
The chief peculiarities in the heart of the foetus are the direct communication 
between the two auricles through the foramen ovale, and the large size of the 
Eustachian valve. There are also several minor peculiarities. Thus, the position 
of the heart is vertical until the fourth month, when it commences to assume an 
oblique direction. Its size is also very considerable as compared with the body, 
the proportion at the second month being 1 to 50; at birth it is as 1 to 120; whilst 
in the adult the average is about 1 to 160. At an early period of festal life the 
auricular portion of the heart is larger than the ventricular, the right auricle being 
more capacious than the left; but toward birth the ventricular portion becomes 
the larger. The thickness of both ventricles is at first about equal, but toward 
birth the left becomes much the thicker of the two. 
The foramen ovale (Fig. 381) is situated at the lower and back part of the septum 
atriorum, forming a communication between the auricles. It remains as a free 
oval opening until the middle period of foetal life. About this period a fold 
grows up from the posterior wall of the auricle to the left of the foramen ovale, and 
advances over the opening so as to form a sort of valve, which allows the blood 
to pass only from the right to the left auricle, and not in the opposite direction. 
The Eustachian valve (Fig. 381) is directed upward on the left side of the 
opening of the inferior vena cava, and serves to direct the blood from this vessel 
through the foramen ovale into the left auricle. 
The peculiarities in the arterial system of the foetus are the communication 
between the pulmonary artery and the descending aorta by means of the ductus THE HEART 
579 
arteriosus, and the communication between the internal iliac arteries and the 
placenta by means of the umbilical arteries. 
The Ductus Arteriosus (Fig. 382).-The ductus arteriosus is a short tube, about 
half an inch in length at birth, and of the diameter of a goose-quill. In the early 
condition it forms the continuation of the pulmonary artery, and opens into the 
descending aorta just below the origin of the left subclavian artery, and so con- 
ducts the chief part of the blood from the right ventricle into this vessel. When 
the branches of the pulmonary artery have become larger relatively to the ductus 
arteriosus, the latter is chiefly connected to the left pulmonary artery; and the 
fibrous cord (ligamentum arteriosum), which is all that remains of the ductus 
arteriosus in later life, will be found to be attached to the root of that vessel. 
The Umbilical Arteries.-The umbilical or hypogastric arteries arise from the 
internal iliacs, in addition to the branches given off from those vessels in the 
adult. Ascending along the sides of the bladder to its apex, they pass out of 
the abdomen at the umbilicus and are continued along the umbilical cord to 
the placenta, coiling round the umbilical vein. They carry to the placenta the 
blood which has circulated in the system of the foetus. 
CONUS 
ARTERIOSUS 
LEFT 
AURICLE 
VALVE OF 
FORAMEN OVALE 
VALVE OF 
CORONARY SINUS 
AU RICU LO-V E NTRICU LA R 
OPENING 
Fig. 381.-The right auricle of a foetal heart (eighth month). Enlarged. (Spalteholz.) 
The peculiarity in the venous system of the foetus is the communication estab- 
lished between the placenta and the liver and portal vein through the umbilical 
vein, and the inferior vena cava through the ductus venosus. 
Foetal Circulation.-The blood destined for the nutrition of the foetus is 
returned from the placenta to the foetus by the umbilical vein. This vein enters 
the abdomen at the umbilicus, and passes upward along the free margin of the 
suspensory ligament of the liver to the under surface of that organ, where it gives 
off two or three branches to the left lobe, one of which is of large size, and others 
to the lobus quadratus and lobulus Spigelii. At the transverse fissure it divides 
into two branches: of these, the larger is joined by the portal vein and enters the 
right lobe; the smaller branch continues outward, under the name of the ductus 
venosus, and joins the left hepatic vein at the point of junction of that vessel with 
the inferior vena cava. The blood, therefore, which traverses the umbilical vein 
reaches the inferior vena cava in three different ways: the greater quantity cir- 
culates through the liver with the portal venous blood before entering the vena THE BLOOD-VASCULAR SYSTEM 
580 
cava by the hepatic veins; some enters the liver directly, and is also returned to 
the inferior cava by the hepatic veins; the smaller quantity passes directly into the 
vena cava by the junction of the ductus venosus with the left hepatic vein. 
.Ductus arteriosus. 
Internal iliac artery. 
Fig. 382.-Plan of the foetal circulation. In this plan the figured arrows represent the kind of blood, as well 
as the direction which it takes in the vessels. Thus, arterial blood is figured >>- --> J venous blood, 
>> >; mixed (arterial and venous) blood, >> •• - •• ->. 
In the inferior cava the blood carried by the ductus venosus and hepatic veins 
becomes mixed with that returning from the lower extremities and wall of the 
abdomen. It enters the right auricle, and, guided by the Eustachian valve, passes 
through the foramen ovale into the left auricle, where it becomes mixed with a 
small quantity of blood returned from the lungs by the pulmonary veins. From 
the left auricle it passes into the left ventricle, and from the left ventricle into THE HEART 
581 
the aorta, by means of which it is distributed almost entirely to the head and 
upper extremities, a small quantity being probably carried into the descending 
aorta. From the head and upper extremities the blood is returned by the tribu- 
taries of the superior vena cava to the right auricle, where it becomes mixed 
with a small portion of the blood from the inferior cava. From the right auricle 
it descends over the Eustachian valve into the right ventricle, and from the right 
ventricle passes into the pulmonary artery. The lungs of the foetus being inactive, 
only a small quantity of the blood of the pulmonary artery is distributed to them 
by the right and left pulmonary arteries, and is returned by the pulmonary veins 
to the left auricle; the greater part passes through the ductus arteriosus into the 
commencement of the descending aorta, where it becomes mixed with a small 
quantity of blood transmitted by the left ventricle into the aorta. Through this 
vessel it descends to supply the lower extremities and viscera of the abdomen 
and pelvis, the chief portion being, however, conveyed by the umbilical arteries 
to the placenta. 
From the preceding account of the circulation of the blood in the foetus it will 
be seen- 
1. That the placenta serves the purposes of nutrition and excretion, receiving 
the impure blood from the foetus, and returning it charged with additional nutri- 
tive material. 
2. That nearly the whole of the blood of the umbilical vein traverses the liver 
before entering the inferior cava; hence the large size of this organ, especially at 
an early period of foetal life. 
3. That the right auricle is the point of meeting of a double current, the blood 
in the inferior cava being guided by the Eustachian valve into the left auricle, 
whilst that in the superior cava descends into the right ventricle. At an early 
period of the foetal life it is highly probable that the two streams are quite dis- 
tinct, for the inferior cava opens almost directly into the left auricle, and the 
Eustachian valve would exclude the current along the vein from entering the 
right ventricle. At a later period, as the separation between the two auricles 
becomes more distinct, it seems probable that some mixture of the two streams 
must take place. 
4. The pure blood carried from the placenta to the foetus by the umbilical vein, 
mixed with the blood from the portal vein and inferior cava, passes almost directly 
to the arch of the aorta, and is distributed by the branches of that vessel to the 
head and upper extremities; hence the large size and perfect development of 
those parts at birth. 
5. The blood contained in the descending aorta, chiefly derived from that 
which has already circulated through the head and upper limbs, together with a 
small quantity from the left ventricle, is distributed to the lower extremities; 
hence the small size and imperfect development of these parts at birth. 
Changes in the Vascular System at Birth. 
At birth, when respiration is established, an increased amount of blood from 
the pulmonary artery passes through the lungs, which now perform their office 
as respiratory organs, and at the same time the placental circulation is cut off. 
Almost immediately after birth the foramen ovale is closed by the valvular edge 
being pressed against the annulus ovalis, the pressure being due to respiration, 
which increases the pressure in the left auricle. The structures fuse, and closure 
is complete by about the tenth day after birth. The valvular fold above men- 
tioned becomes adherent to the margins of the foramen for the greater part of its 
circumference, but above a slit-like opening is left between the two auricles which 
sometimes remains persistent. 582 
THE BLOOD-VASCULAR SYSTEM 
The ductus arteriosus begins to contract immediately after respiration is estab- 
lished, becomes completely closed from the fourth to the tenth day, and ultimately 
degenerates into an impervious cord which serves to connect the left pulmonary 
artery to the descending aorta. W hen respiration begins, the caval opening of 
the diaphragm being fixed and the balance of the muscle rising and falling, the 
ductus arteriosus is compressed by the muscular structures which pass from the 
diaphragm to the pericardium, is narrowed, and is finally obliterated (Forbes). 
Of the umbilical or hypogastric arteries, the portion continued on to the bladder 
from the trunk of the corresponding internal iliac remains pervious as the superior 
vesical artery, and the part extending from the side of the bladder to the umbilicus 
becomes obliterated between the second and fifth days after birth, and projects 
as a fibrous cord toward the abdominal cavity, carrying on it a fold of peritoneum 
and separating two of the fossae of the peritoneum spoken of in the section on the 
surgical anatomy of direct inguinal hernia. 
The umbilical vein and the ductus venosus become completely obliterated 
between the second and fifth days after birth, and ultimately dwindle to fibrous 
cords, the former becoming the round ligament of the liver, the latter the fibrous 
cord, which in the adult may be traced along the fissure of the ductus venosus. THE ARTERIES. 
The Arteries are cylindrical tubular vessels which serve to convey blood from 
both ventricles of the heart to every part of the body. These vessels were named 
arteries (dqp, air; to contain) from the belief entertained by the ancients 
that they contained air. To Galen is due the honor of refuting this opinion; he 
showed that these vessels, though for the most part empty after death, contain 
blood in the living body. 
The distribution of the systemic arteries is like a highly ramified tree, the 
common trunk of which, formed by the aorta, commences at the left ventricle of 
the heart, the smallest ramifications corresponding to the circumference of the 
body and the contained organs. The arteries are found in nearly every part of 
the body, with the exception of the hairs, nails, epidermis, cartilages, and cornea; 
and the larger trunks usually occupy the most protected situations, running, in 
a limb, along the flexor side, where they are less exposed to injury. 
There is considerable variation in the mode of division of the arteries: occa- 
sionally a short trunk subdivides into several branches at the same point, as 
we observe in the coeliac and thyroid 
axes; or the vessel may give off several 
branches in succession, and still con- 
tinue as the main trunk, as is seen in 
the arteries of the limbs; but the usual 
division is dichotomous; as, for instance, 
the aorta dividing into the two common 
iliacs, and the common carotid into the 
external and internal carotids. 
The branches of arteries arise at very 
variable angles: some, as the superior 
intercostal arteries from the aorta, arise 
at an obtuse angle: others, as the lumbar 
arteries, at a right angle; or, as the 
spermatic, at an acute angle. An artery 
from below the point at which a branch 
is given off is smaller in size than be- 
fore. It retains a uniform diameter 
until a second branch is derived from 
it. A branch of an artery is smaller 
than the trunk from which it arises; but 
if an artery divides into two branches, 
the combined area of the two vessels is, in nearly every instance, somewhat 
greater than that of the trunk; and the combined area of all the arterial branches 
greatly exceeds the area of the aorta; so that the arteries collectively may be 
regarded as a cone, the apex of wfliich corresponds to the aorta, the base to the 
capillary system. 
The arteries, in their distribution, communicate with one another, forming 
what is called an anastomosis (d>a, between; aTopa, mouth) or inosculation (Fig. 
383); and this communication is very free between the larger as well as between the 
A B 
D 
C E 
Fig. 383.-Diagram showing the anastomosis of 
arteries. (Poirier and Charpy.) 
583 584 
THE BLOOD-VASCULAR SYSTEM 
smaller branches. An anastomosis between trunks of equal size is found where 
great activity of the circulation is requisite, as at the base of the brain; here the 
two vertebral arteries unite to form the basilar, and the two internal carotid 
arteries are connected by a short communicating trunk; it is also found in the 
abdomen, the intestinal arteries having very ample anastomoses between their 
larger branches. In the limbs the anastomoses are most numerous and of 
largest size around the joints, the branches of an artery above inosculating 
with branches from the vessels below; these anastomoses are of considerable 
interest to the surgeon, as it is by their enlargement that a collateral circula- 
tion is established after the application of a ligature to an artery for the cure 
of aneurism. The smaller branches of arteries anastomose more frequently 
than the larger, and between the smallest twigs these inosculations become so 
numerous as to constitute a close network 
that pervades nearly every tissue of the body. 
A terminal artery is one which forms no 
anastomoses. Such vessels are found in the 
brain, spleen, kidneys, lungs, and mesen- 
tery. 
Throughout the body generally the larger 
arterial branches pursue a perfectly straight 
course, but in certain situations they are tor- 
tuous; thus the facial arteries in their course 
over the face, and the arteries of the lips, 
are extremely tortuous in their course, to 
accommodate themselves to the movements 
of the parts. The uterine arteries are also 
tortuous, to accommodate themselves to the 
increase of size which the organ undergoes 
during pregnancy. Again, the internal 
carotid and vertebral arteries, previous to 
their entering the cavity of the skull, de- 
scribe a series of curves, which are evidently 
intended to diminish the velocity of the cur- 
rent of blood by increasing the extent of 
surface over which it moves and adding to 
the resistance which is produced by friction. 
The arteries are dense in structure, of 
considerable strength, highly elastic, and, 
when divided, they preserve, although empty, 
their cylindrical form. 
Histology of the Capillaries and Ar- 
teries. The Capillaries (Fig. 386).-The 
capillaries are very small endothelial tubes 
which connect the venous system with the 
arterial system. In diameter they vary from ^o °f an inch, in length 
from to of an inch. The nucleated endothelial cells which constitute the 
wall of a capillary are flat, irregular in outline, and are united by a cement 
material. Small openings (stomata) are frequently noted between these cells, 
but they are probably artifacts and do not exist during life. 
The capillaries anastomose and form vast networks. When an artery is about 
to become a capillary the muscular coat disappears. The endothelial coat which 
constitutes the capillaries extends as a system of endothelial tubes throughout the 
entire blood-vascular system. The heart is a great muscular thickening around 
a portion of the system of endothelial tubes. An artery consists of an endothelial 
V 
A 
Fig. 384.-Transverse section through a small 
artery and vein of the mucous membrane of the 
epiglottis of a child. Magnified about 350 diame- 
ters. A, artery, showing the nucleated endothe- 
lium e, which lines it: the vessel being con- 
tracted, the endothelial cells appear very thick. 
Underneath the endothelium is the wavy elastic 
intima. The chief part of the wall of the vessel 
is occupied by the circular muscle-coat m; the 
staff-shaped nuclei of the muscle-cells are well 
seen. Outside this is a, part of the adventitia. 
This is composed of bundles of connective-tissue 
fibres, shown in section, with the nuclei of the 
connective-tissue corpuscles. The adventitia 
gradually merges into the surrounding connective- 
tissue. V, vein showing a thin endothelial mem- 
brane e, raised accidentally from the intima, 
which on account of its delicacy is seen as a mere 
line on the media m. This latter is composed of 
a few circular unstriped muscle-cells ; a, the ad- 
ventitia, similar in structure to that of an artery. 
(Klein and Noble Smith.) THE ARTERIES 
585 
tube covered by certain accessory coats. The wall of an artery diminishes 
greatly in thickness (Fig. 387) and is found to be composed of endothelial cells 
and scattered unstriated muscle-fibres, covered merely by thin connective tissue 
or elastic-tissue sheath (adventitia capillaris). Such a structure is known as an 
arteriole or a precapillary artery. By the loss of its thin sheath of connective or 
elastic tissue it becomes a capillary. A capillary takes on a thin sheath and 
becomes a venule or precapillary vein. Nerves do not terminate in capillaries, 
but networks of nerve-filaments often encompass these small vessels. 
An artery consists of an internal coat or tunica intima, a middle coat or tunica 
media, and an external coat or tunica adventitia (Figs. 384 and 385). 
'The Inner Coat (tunica intima) consists of endothelial cells and yellow elastic 
tissue. In some cases the elastic fibres are arranged longitudinally, but, as a rule, 
they form a distinct fenestrated membrane known as the fenestrated membrane of 
Endothelial and sub- 
endothelial layer of 
' inner coat. 
'Elastic layer. 
Innermost layers of 
middle coat. 
Outermost layers of 
middle coat. 
Innermost part 
outer coat. 
Outer part of outer 
coat. 
Fig. 385.-Section of a medium-sized artery. (After Griinstein.) 
Henle, or the internal elastic coat. In medium-sized vessels the elastic layer of the 
intima is separated from the endothelial layer by a layer of connective tissue. 
In the large arteries the interposed layer of connective tissue is thicker and con- 
tains elastic fibres. 
The Middle Coat (tunica media) consists of muscle, elastic tissue, and white 
fibrous tissue, and it is often called the elastomuscular coat. The arterioles con- 
tain scattered unstriated muscle fibres. In the small arteries they constitute a 
thin but definite coat. In larger arteries the muscular coat is much thicker. The 
muscle is unstriated and the fibres are arranged circularly, and in the larger 
vessels form layers which are separated by elastic fibres. Here and there longi- 
tudinally-disposed muscle-fibres exist. The larger the artery the greater is the 
amount of elastic tissue existing in the middle coat. In the aorta and in some 
of the very large arteries the amount of elastic tissue exceeds the amount of THE BLOOD-VASCULAR SYSTEM 
586 
muscular tissue. " In the first part of the aorta, in the pulmonary artery and in 
the arteries of the retina, the muscular fibres are entirely replaced by elastic 
tissue."1 The arteries within the skull have no elastic tissue in the media, 
although they have some in the adventitia. 
The External Coat (tunica adventitia) is called the fibrous coat. It contains 
fibrous connective tissue, elastic tissues, and in some arteries fibres of unstriated 
muscle arranged longitudinally. The circular elastic membrane which sepa- 
rates the outer coat from the middle coat is known as the external elastic mem- 
brane. 
Blood-vessels of the Blood-vessel Wall.-Many small blood-vessels course in the 
external and middle coats of arteries of large and of moderate size. They are 
mostly in the adventitia. They may arise from the vessel to which they are dis- 
Fig. 386.-Capillaries from the 
mesentery of a guinea-pig after treat- 
ment with solution of nitrate of silver. 
a, cells; b, their nuclei. 
Fig. 387.-Finest vessels on the arterial side. From the human 
brain. Magnified 300 times. 1, small artery; 2, transition vessel; 
3, coarser capillaries; 4, finer capillaries; a, structureless mem- 
brane still with some nuclei, representative of the tunica adven- 
titia; b, nuclei of the muscular fibre-cells; c, nuclei within the 
small artery, perhaps appertaining to an endothelium; d, nuclei 
in the transition vessels. 
tributed or take origin from an adjacent vessel. These small arteries are called 
the vasa vasorum. The blood is returned from the walls of the vessels by small 
veins. 
Lymphatics.-Distinct lymphatic vessels may exist in the adventitia, but are 
not found in either of the other coats. Lymph-capillaries often surround small 
blood-vessels or a small blood-vessel may lie in a perivascular lymph-space. 
Nerves.-Arteries are supplied with nerves, medullated and non-medullated. 
A network of nerve-fibres may surround a vessel and usually capillaries are so 
surrounded. In the arteries a network of nerves exists in the media. These nerves 
supply the muscle-fibres and are called vasomotor nerves. 
The Arterial Sheath (vagina vasis) surrounds the artery. It is composed of con- 
nective tissue and is attached to the vessel at numerous points by fibrous tissue. 
1 D. J. Cunningham. Text-book of Anatomy. 77/A' AORTA 
587 
PULMONARY ARTERY (A. PULMONALIS) (Fig. 389, 391). 
In the description of the arteries we shall first consider the efferent trunk of 
the pulmonic circulation, the pulmonary artery, and then the efferent trunk of the 
systemic circulation, the aorta and its branches. 
The pulmonary artery conveys the venous blood from the right side of the heart 
to the lungs. It is a short, wide vessel, about 2 inches in length and Id inches 
(30 mm.) in diameter, arising from the left side of 4he base (conus arteriosus) 
of the right ventricle, in front of the aorta. It extends obliquely upward and 
backward, passing at first in front of and then to the left of the ascending 
aorta, as far as the under surface of the arch, where it divides, about on a level 
with the intervertebral substance between the fifth and sixth dorsal vertebrae, 
into two branches of nearly equal size, the right and left pulmonary arteries. 
The Right Pulmonary Artery (ramus dexter a. pulmonalis), longer and 
larger than the left, runs horizontally outward to the root of the right lung, where 
it divides into two branches, of which the lower and larger supplies the middle 
and lower lobes; the upper and smaller is distributed to the upper lobe. It has 
in front of it the ascending aorta, the superior vena cava, and the right phrenic 
nerve. It has behind it the right bronchus. Above it is the transverse portion of 
the arch of the aorta. Below it is the right auricle. 
The Left Pulmonary Artery (ramus sinister a. pulmonalis), shorter and 
somewhat smaller than the right, passes horizontally to the root of the left lung, 
where it divides into two branches for the two lobes. In front of it and below it 
are the pulmonary veins of the left side. Behind are the descending aorta and the 
left bronchus. Above it are the arch of the aorta, the left recurrent laryngeal 
nerve, and the ductus arteriosus. The left bronchus in a portion of its course lies 
below as well as behind. 
Relations.-The whole of the vessel is contained, together with the ascending 
aorta, in the pericardium. It is enclosed with the aorta in a single tube of the 
serous pericardium, which is continued upward upon them from the base of the 
heart and connects them together. The fibrous layer of the pericardium becomes 
gradually lost upon the external coats of its two branches. In jront, the pulmonary 
artery is separated from the anterior extremity of the second left intercostal space 
by the pleura and left lung, in addition to the pericardium; it rests at first upon 
the ascending aorta, and higher up lies in front of the left auricle on a plane 
posterior to the ascending aorta. On each side of its origin is the appendix of 
the corresponding auricle and a coronary artery, the left coronary artery passing, 
in the first part of its course, behind the vessel. 
The root of the left pulmonary artery is connected to the under surface of the 
arch of the aorta by a short fibrous cord, the ligamentum arteriosum; this is the 
remains of a vessel peculiar to foetal life, the ductus arteriosus. 
The terminal branches of the pulmonary artery will be described with the 
anatomy of the lung. 
THE AORTA (Figs. 388, 389, 390, 391). 
The aorta or arteria magna (dopr^) is the main trunk of a series of vessels which 
convey the oxygenated blood to the tissues of the body for their nutrition. This 
vessel commences at the upper part of the left ventricle, where it is about one and 
one-eighth inches in diameter, and, after ascending for a short distance, arches 
backward and to the left side, over the root of the left lung, then descends within 
the thorax on the left side of the vertebral column, passes through the aortic open- 
ing in the Diaphragm, and, entering the abdominal cavity, terminates, consider- 588 
THE BLOOD-VASCULAR SYSTEM 
ably diminished in size (about seven-tenths of an inch in diameter), opposite the 
lower border of the fourth lumbar vertebra, where it divides into the right and left 
common iliac arteries. Hence it is divided into the ascending aorta, the arch of 
the aorta, and the descending aorta, which last is again divided into the thoracic aorta 
and the abdominal aorta, from the position of these parts. 
THE ASCENDING AORTA (AORTA ASCENDENS). 
The ascending aorta is about two inches in length. It commences at the 
upper part of the left ventricle, on a level with the lower border of the third 
costal cartilage, behind the left half of the sternum; it passes obliquely upward, 
forward, and to the right, in the direction of the heart's axis, as high as the 
PNEUMOGASTRIC 
NERVE 
CARDIAC NERVE 
SUPERIOR INTER* 
COSTAL VEIN 
CARDIAC NERVE 
ARTERIAL 
LIGAMENTS 
VENA AZYGOS 
MINOR 
.SYMPATHETIC 
GANGLION 
SYM PATHETIC 
NERVE 
PHRENIC 
NERVE 
Fig. 388.-Arch of the aorta and its relations. (Poirier and Charpy.) 
upper border of the second right costal cartilage, describing a slight curve in 
its course, and being situated, when distended, about a quarter of an inch behind 
the posterior surface of the sternum. A little above its commencement it is some- 
what enlarged (bulbus aortce), and presents three small dilatations, one of which is 
anterior, two of which are posterior, which are called the sinuses of Valsalva (sinus 
aortce). Opposite to the sinuses are attached the three semilunar valves (Fig. 376), THE ASCENDING AORTA 
589 
which serve the purpose of preventing any regurgitation of blood into the cavity 
of the ventricle. These valves are placed one in front and two behind. At the 
union of the ascending with the transverse part of the aorta the calibre of the vessel 
is increased, owing to a bulging outward of its right wall. This dilatation is termed 
the great sinus of the aorta. A section of the aorta opposite this part has a some- 
what oval figure; but below the attachment of the valves it is circular. This por- 
tion of the aorta is contained in the cavity of the pericardium, and, together with 
the pulmonary artery, is invested in a tube of serous membrane, continued on to 
them from the surface of the heart. 
Left vagus. 
Recurrent laryngeal.. 
Right vagus.' 
■Left phrenic. 
Thoracic duct. 
Right Coronary 
Artery 
.Left Coronary 
Artery 
Fig. 390.-Plan of the 
branches. 
Fig. 389.-The arch of the aorta and its branches. 
Relations.-The ascending aorta is covered at its commencement by the trunk 
of the pulmonary artery and the right auricular appendix, and, higher up, is 
separated from the sternum by the pericardium, the right pleura, and anterior 
margin of the right lung, some loose areolar tissue, and the remains of the thymus 
gland; behind, it rests upon the right pulmonary artery, left auricle, and the right 
bronchus. On the right side it is in relation with the superior vena cava and right 
auricle; on the left side, with the pulmonary artery 590 
THE BLOOD-VASCULAR SYSTEM 
Plan of the Relations of the Ascending Aorta 
In front. 
Pulmonary artery. 
Right auricular appendix. 
Pericardium. 
Right pleura and lung. 
Remains of the thymus gland 
Right side. 
Superior vena cava. 
Right auricle. 
Ascending 
Aorta. 
Left side. 
Pulmonary artery. 
Behind. 
Right pulmonary artery. 
Left auricle. 
Right bronchus. 
Branches-The only branches of the ascending aorta are the coronary arteries. 
They supply the heart, and are two in number, right and left, arising near the com- 
mencement of the aorta, immediately above the free margin of the semilunar 
valves. 
The Coronary Arteries (Fig. 389). 
The Right Coronary Artery (a. coronaria [cort/w] dextra), about the size of a 
crow's quill, arises from the anterior sinus of Valsalva. It passes forward between 
the pulmonary artery and the right auricular appendix, then runs obliquely to the 
right side, in the groove between the right auricle and ventricle, and, curving 
around the right border of the heart, runs to the left along its posterior surface as 
far as the posterior interventricular groove, where it divides into two branches, one 
of which, the transverse, continues onward in the groove between the left auricle 
and ventricle, and anastomoses with the left coronary; the other, the descending 
(ramus descendens posterior a. coronaricc [corc/w] dextroe), courses along the posterior 
interventricular furrow, supplying branches to both ventricles and to the septum, 
and anastomosing at the apex of the heart with the descending branches of the left 
coronary. This vessel sends a large branch, the marginal, along the thin margin 
of the right ventricle to the apex, which in its course gives off numerous small 
branches to the anterior and posterior surfaces of the ventricle. It also gives off 
a branch, the infundibular, which ramifies over the front part of the conus arte- 
riosus of the right ventricle. 
The Left Coronary Artery (a. coronaria [cort/u1] sinistra), larger than the 
former, arises from the left posterior sinus of Valsalva; it passes forward between 
the pulmonary artery- and the left auricular appendix, and divides into two 
branches. Of these, one, the transverse, passes transversely outward in the left 
auriculo-ventricular groove, and winds around the left border of the heart to its 
posterior surface, where it anastomoses with the transverse branch of the right 
coronary; the other, the descending (ramus descendens anterior a. coronarice [corah's1] 
sinistrce), passes along the anterior interventricular groove to the apex of the heart, 
where it anastomoses with the descending branches of the right coronary. The left 
coronary supplies the left auricle and its appendix, gives branches to both ventri- 
cles, and numerous small branches to the pulmonary artery and commencement 
of the aorta.1 
1 According to Dr. Samuel West, there is a very free and complete anastomosis between the two coronary 
arteries (Lancet, June 2, 1883, p. 945). This, however, is not the view generally held by anatomists, for, with 
the exception of the anastomosis mentioned above in the auriculo-ventricular and interventricular grooves, it 
is believed that the two arteries only communicate by very small vessels in the substance of the heart.-Ed. of 
15th English edition. THE ARCH OF THE AORTA 
591 
Peculiarities.-These vessels occasionally arise by a common trunk, or their number may 
be increased to three, the additional branch being of small size. More rarely there are two 
additional branches. 
THE ARCH OF THE AORTA 
The arch, or transverse aorta (arcus aort(e), commences at the upper border of 
the second chondro-sternal articulation of the right side, and passes at first upward 
and backward and from right to left, and then from before backward, to the left 
side of the lower border of the fourth dorsal vertebra behind. Its upper border is 
usually about an inch below the upper margin of the sternum. 
Between the origin of the left subclavian artery and the attachment of the 
ductus arteriosus the lumen of the foetal aorta is considerably narrowed, forming 
what is termed the aortic isthmus (isthmus aorta1), while immediately beyond the 
ductus arteriosus the vessel presents a fusiform dilatation which His has named 
the aortic spindle (aortenspiudel)-the point of junction of the two parts being 
marked in the concavity of the arch by an indentation or angle. These con- 
ditions persist, to some extent, in the adult, where His found that the average 
diameter of the spindle exceeded that of the isthmus by 3 mm. (about one-eighth 
of an inch). 
Relations.-Its anterior surface is covered by the pleurae and lungs (much 
more by the left lung than by the right) and the remains of the thymus gland, and 
crossed toward the left side by the left pneumogastric and phrenic nerves and 
superficial cardiac branches of the left sympathetic and vagus, and by the left 
superior intercostal vein. Its posterior surface lies on the trachea, just above its 
bifurcation, on the great, or deep, cardiac plexus, the oesophagus, thoracic duct, 
and left recurrent laryngeal nerve. Its upper border is in relation with the left 
innominate vein, and from its upper part are given off the innominate, left com- 
mon carotid and left subclavian arteries. Its lower border is in relation with the 
bifurcation of the pulmonary artery, the remains of the ductus arteriosus, which 
is connected with the left division of that vessel, and the superficial cardiac plexus; 
the left recurrent laryngeal nerve winds round it from before backward, whilst 
the left bronchus passes below it. 
Plan of the Relations of the Arch of the Aorta. 
Above. 
Left innominate vein. 
Innominate artery. 
Left carotid. 
Left subclavian. 
In Front. 
Pleurte and lungs. 
Remains of thymus gland. 
Left pneumogastric nerve. 
Left phrenic nerve. 
Superficial cardiac nerves. 
Left superior intercostal vein. 
Behind. 
Trachea. 
Deep cardiac plexus. 
(Esophagus. 
Thoracic duct. 
Left recurrent nerve. 
Arch of 
Aorta. 
Below. 
Bifurcation of pulmonary artery. 
Remains of ductus arteriosus. 
Superficial cardiac plexus. 
Left recurrent nerve. 
Left bronchus. 
Peculiarities.-The height to which the aorta rises in the chest is usually about an inch below 
the upper border of the sternum; but it may ascend nearly to the top of that bone. Occasionally 
it is found an inch and a half, more rarely two or even three inches, below this point. 592 
THE BLOOD-VASCULAR SYSTEM 
In Direction.-Sometimes in man, as is normal in birds, the aorta arches over the root of 
the right instead of the left lung, and passes down on the right side of the spine. In such cases 
all of the viscera of the thoracic and abdominal cavities are transposed. Less frequently, the 
aorta, after arching over the root of the right lung, is directed to its usual position on the left 
side of the spine, this peculiarity not being accompanied by any transposition of the viscera. 
In Conformation.-The aorta occasionally divides, as in some quadrupeds, into an ascend- 
ing and descending trunk, the former of which is directed vertically upward, and subdivides 
into three branches, to supply the head and upper extremities. Sometimes the aorta subdivides 
soon after its origin into two branches, which soon reunite. In one of these cases the oesophagus 
and trachea were found to pass through the interval left by the division of the aorta; this is 
the normal condition of the vessel in the reptilia. 
Surgical Anatomy.-Of all the vessels of the arterial system, the aorta, and more especially 
its arch, is most frequently the seat of disease; hence it is important to consider some of the 
consequences that may ensue from aneurism of this part. 
It will be remembered that the ascending aorta is continued in the pericardium, just behind 
the sternum, being crossed at its commencement by the pulmonary artery and right auricular 
appendix, and having the right pulmonary artery behind, the vena cava on the right side, and 
the pulmonary artery and left auricle on the left side. 
Right pulmonary 
vein. 
Right pulmonary 
vein. . 
Left subclavian 
artery. 
Left common 
carotid artery. 
Vena azygos' 
major. 
-Left innomi- 
nate vein. 
Inferior thyroid 
vein. 
Right innomi- 
nate vein. 
Right subclavian artery. 
Right common carotid artery. 
Fig. 391.-Relation of great vessels at base of heart, seen from above. (From a preparation in the Museum 
of the Royal College of Surgeons of England.) 
Aneurism of the ascending aorta, in the situation of the sinuses of Valsalva, in the great major- 
ity of cases, affects the anterior sinus; this is mainly owing to the fact that the regurgitation 
of blood upon the sinuses takes place chiefly on the anterior aspect of the vessel. As the aneuris- 
mal sac enlarges it may compress any or all of the structures in immediate proximity to it, 
but chiefly projects toward the right anterior side, and, consequently, interferes mainlv with 
those structures that have a corresponding relation with the vessel. In the majority of cases it 
bursts into the cavity of the pericardium, the patient suddenly drops dead, and, upon a post- 
mortem examination, the pericardial sac is found full of blood; or it may compress the right 
auricle, or the pulmonary artery and adjoining part of the right ventricle, and open into one or 
the other of these parts, or may press upon the superior vena cava. 
Aneurism of the ascending aorta, originating above the sinuses, most frequently implicates 
the right anterior wall of the vessel, where, as has been explained, there exists a normal dilata- 
tion, the great sinus of the aorta; this is probably mainly owing to the blood being impelled 
against this part. The direction of the aneurism is also chiefly toward the right of the median 
line. It attains a large size and projects forward, it may absorb the sternum and the cartilages 
of the ribs, usually on the right side, and appear as a pulsating tumor on the front of the chest, 
just below the manubrium; or it may burst into the pericardium, or may compress or open into 
the right lung, the trachea, bronchi, or oesophagus. THE INNOMINATE ARTERY 
593 
Regarding the transverse aorta, the student is reminded that the vessel lies on the trachea, 
the oesophagus, and thoracic duct; that the recurrent laryngeal nerve winds around it; and that 
from its upper part are given off three large trunks, which supply the head, neck, and upper 
extremities. An aneurismal tumor, taking origin from the posterior part of the vessel, its most 
usual site, may press upon the trachea, impede the breathing, or produce cough, haemoptysis, 
or stridulous breathing, or it may ultimately burst into that tube, producing fatal haemorrhage. 
Again, its pressure on the laryngeal nerves may give rise to symptoms which so accurately 
resemble those of laryngitis that the operation of tracheotomy has in some cases been resorted 
to, from the supposition that disease existed in the larynx; or it may press upon the thoracic 
duct and destroy life by inanition; or it may involve the oesophagus, producing dysphagia; or 
may burst into the oesophagus, when fatal hemorrhage will occur. Again, the innominate 
artery, or the subclavian, or left carotid, may be so obstructed by clots as to produce a weakness, 
or even a disappearance, of the pulse in one or the other wrist or in the left temporal artery; or 
the tumor may present itself at or above the manubrium, generally either in the median line 
or to the right of the sternum, and may simulate an aneurism of one of the arteries of the neck. 
Branches (Figs. 389 and 390).-The branches given off from the arch of the 
aorta are three in number: the innominate, the left common carotid, and the left 
subclavian arteries. 
Peculiarities. Position of the Branches.-The branches, instead of arising from the high- 
est part of the arch (their usual position), may be moved more to the right, arising from the 
commencement of the transverse or upper part of the ascending portion; or the distance from 
one another at their origin may be increased or diminished, the most frequent change in this 
respect being the approximation of the left carotid toward the innominate artery. 
The Number of the primary branches may be reduced to a single vessel, or more commonly 
two: the left carotid arising from the innominate artery, or (more rarely) the carotid and sub- 
clavian arteries of the left side arising from the innominate artery. But the number may be 
increased to four, from the right carotid and subclavian arteries arising directly from the aorta, 
the innominate being absent. In most of these latter cases the right subclavian has been found 
to arise from the left end of the arch; in other cases it was the second or third branch given off 
instead of the first. Another common form in which there are four primary branches is that 
in which the left vertebral artery arises from the arch of the aorta between the left carotid and 
subclavian arteries. Lastly, the number of trunks from the arch may be increased to five or 
six; in these instances, the external and internal carotids arise separately from the arch, the 
common carotid being absent on one or both sides. In some cases, where six branches have 
been found, it has been due to a separate origin of the vertebral on both sides. 
Number as Usual, Arrangement Different.-When the aorta arches over to the right 
side, the three branches have an arrangement the reverse of what is usual, the innominate sup- 
plying the left side, and the carotid and subclavian (which arise separately) the right side. In 
other cases, where the aorta takes its usual course, the two carotids may be joined in a common 
trunk, and the subclavians arise separately from the arch, the right subclavian generally arising 
from the left end of the arch.1 
In some instances other arteries are found to arise from the arch of the aorta. Of these the 
most common are the bronchial, one or both, and the thyroidea ima; but the internal mammary 
and the inferior thyroid have been seen to arise from this vessel. 
The Innominate Artery (A. Anonyma) (Figs. 389, 390, 391). 
The innominate or brachio-cephalic artery is the largest branch given off 
from the arch of the aorta. It arises, on a level with the upper border of 
the second right costal cartilage, from the commencement of the arch of the 
aorta in front of the left carotid, and, ascending obliquely to the upper border of 
the right sterno-clavicular articulation, divides into the right common carotid and 
right subclavian arteries. This vessel varies from an inch and a half to two inches 
in length. 
Relations.-In front, it is separated from the first piece of the sternum by the 
Sterno-hyoid and Sterno-thyroid muscles, the remains of the thymus gland, the 
left innominate and right inferior thyroid veins which cross its root, and some- 
times the inferior cervical cardiac branch of the right pneumogastric. Behind, it 
1 The anomalies of the aorta and its branches are minutely described by Krause in Henle's Anatomy (Bruns- 
wick, 1868), vol. iii. p. 203 et seq.-Ed. of 15th English edition 594 
THE BLOOD-VASCULAR SYSTEM 
lies upon the trachea, which it crosses obliquely, and continuing upward it lies 
in the right pleura. On the right side is the right innominate vein, right pneumo- 
gastric nerve, and the pleura; and on the left side, the remains of the thymus gland, 
the origin of the left carotid artery, the left inferior thyroid vein, and the trachea. 
Branches.-The innominate usually gives off no branches, but occasionally a 
small branch, the thyroidea ima, is given off from this vessel. It also sometimes 
gives off a thymic or bronchial branch. 
The Thyroidea Ima (a. thyroidea ima), which is occasionally present, ascends in 
front of the trachea to the lower part of the thyroid body, which it supplies. It 
varies greatly in size, and appears to compensate for the deficiency or absence of 
one of the other thyroid vessels. It occasionally is found to arise from the right 
common carotid or from the aorta, the subclavian, or internal mammary vessels. 
Plan of the Relations of the Innominate Artery. 
In front. 
Sternum. 
Sterno-hyoid and Sterno-thyroid muscles. 
Remains of the thymus gland. 
Left innominate and right inferior thyroid veins. 
Inferior cervical cardiac branch from right pneumogastric nerve. 
Right side. 
Right innominate vein. 
Right pneumogastric nerve. 
Pleura. 
Innominate 
Artery. 
Left side. 
Remains of thymus. 
Left carotid. 
Left inferior thyroid vein. 
Trachea. 
Behind. 
Trachea. 
Right pleura. 
Peculiarities in Point of Division.-When the bifurcation of the innominate artery varies 
from the point above mentioned it sometimes ascends a considerable distance above the sternal 
end of the clavicle; less frequently it divides below it. In the former class of cases its length 
may exceed two inches, and in the latter be reduced to an inch or less. These are points of con- 
siderable interest for the surgeon to remember in connection with the operation of tying this 
vessel. 
Position.-When the aorta arches over to the right side, the innominate is directed to the 
left side of the neck instead of the right. 
Collateral Circulation.-Allan Burns demonstrated, on the dead subject, the possibility of 
the establishment of the collateral circulation after ligature of the innominate artery, by tying 
and dividing that artery, after which, he says, "Even coarse injection, impelled into the aorta, 
passing freely by the anastomosing branches into the arteries of the right arm, filling them and 
all the vessels of the head completely."1 The branches by which this circulation would be car- 
ried on are very numerous; thus, all the communications across the middle line between the 
branches of the carotid arteries of opposite sides would be available for the supply of blood to 
the right side of the head and neck; while the anastomosis between the superior intercostal of 
the subclavian and the first aortic intercostal (see infra on the collateral circulation after oblitera- 
tion of the thoracic aorta) would bring the blood, by a free and direct course, into the right 
subclavian: the numerous connections, also, between the intercostal arteries and the branches 
of the axillary and internal mammary arteries would, doubtless, assist in the supply of blood to 
the right arm, while the deep epigastric, from the external iliac, would, by means of its anasto- 
mosis with the internal mammary, compensate for any deficiency in the vascularity of the wall 
of the chest. 
Surgical Anatomy.-The innominate artery has been tied at least thirty times and in six 
instances, according to Mr. Jacobson, the patient survived. Mott's patient, however, on 
whom the operation was first performed, lived nearly four weeks, and Graefe's more than 
two months. In 1895 Burrell, of Boston, resected the right sterno-clavicular articulation with 
the upper end of the sternum and tied the innominate. The patient lived 104 days. The 
1 Surgical Anatomy of the Head and Neck, p. 62. THE COMMON CAROTID ARTERY 
595 
ligation was first successfully performed by A. W. Smyth, of New Orleans, in 1864, for sub- 
clavian aneurism. The patient died ten years later of the original aneurism, which was reformed 
by the collaterals. The chief danger of the operation appears to be the frequency of secondary 
hemorrhage; but in the present day, with the practice of aseptic surgery and our greater 
knowledge of the use of the ligature, more favorable results may be anticipated. Other causes 
of death after operation are pleurisy, pericarditis, and suppurative cellulitis. The main 
obstacles to the operation are, as the student will perceive from his dissection of this vessel, 
the deep situation of the artery behind and beneath the sternum, and the number of important 
structures which surround it in every part. 
In order to apply a ligature to this vessel, the patient is to be placed upon his back, with the 
thorax slightly raised, the head bent a little backward, and the shoulder on the side of the aneu- 
rism strongly depressed, so as to draw out the artery from behind the sternum into the neck. 
An incision three or more inches long is then made along the anterior border of the Sterno-mas- 
toid muscle, terminating at the sternal end of the clavicle. From this point a second incision is 
carried about the same length along the upper border of the clavicle. The skin is then dissected 
back, and the Platysma divided on a director: the sternal end of the Sterno-mastoid is now 
brought into view, and, a director being passed beneath it and close to its under surface, so as to 
avoid any small vessels, it is to be divided; in like manner the clavicular origin is to be divided 
throughout the whole or greater part of its attachment. By pressing aside any loose cellular 
tissue or vessels that may now appear the Sterno-hyoid and Sterno-thyroid muscles will be 
exposed, and must be divided, a director being previously passed beneath them. The inferior 
thyroid veins may come into view, and must be carefully drawn, either upward or downward, by 
means of a blunt hook, or tied with double ligatures and divided. After tearing through a 
strong fibro-cellular lamina, the right carotid is brought into view, and, being traced downward, 
the arteria innominata is arrived at. The left innominate vein should now be depressed; the 
right innominate vein, the internal jugular vein, and the pneumogastric nerve drawn to the right 
side; and a curved aneurism needle may then be passed around the vessel, close to its surface, 
and in a direction from below upward and inward, care being taken to avoid the right pleural 
sac, the trachea, and cardiac nerves. The ligature should be applied to the artery as high as 
possible, in order to allow room between it and the aorta for the formation of the coagulum. 
The importance of avoiding the thyroid plexus of veins during the primary steps of the opera- 
tion, and the pleural sac whilst including the vessel in the ligature, should be most carefully borne 
in mind. After the artery has been secured, the common carotid should be tied about half an 
inch above its origin, and also the thyroidea ima if the vessel is of any size. The several muscles 
are united by buried sutures. An easier and safer plan than the above is that employed by 
Burrell-viz., resection of the right sterno-clavicular articulation and of the upper end of the 
sternum. 
ARTERIES OF THE HEAD AND NECK. 
The chief artery which supplies the head and neck is the common carotid: it 
ascends in the neck and divides into two branches: the External Carotid, supply- 
ing the superficial parts of the head and face and the greater part of the neck; 
and the Internal Carotid, supplying to a great extent the parts within the cranial 
cavity. 
THE COMMON CAROTID ARTERY (A. CAROTIS COMMUNIS) (Figs. 388, 389, 
390, 392). 
The common carotid arteries, although occupying a nearly similar position in 
the neck, differ in position, and, consequently, in their relation at their origin. 
The right common carotid (a. carotis communis dextra) arises from the innom- 
inate artery, behind the right sterno-clavicular articulation. The left common 
carotid (a. carotis communis sinistra) arises from the highest part of the arch of 
the aorta, and is, consequently, longer, and at its origin is contained within 
the thorax. The course and relations of that portion of the left carotid which 
intervenes between the arch of the aorta and the left sterno-clavicular articulation 
will first be described. (See Figs. 388, 389, and 390.) 
The left carotid within the thorax ascends obliquely outward from the arch of 
the aorta to the root of the neck. In front, it is separated from the first piece 
of the sternum by the Sterno-hyoid and Sterno-thyroid muscles, the left innomi- 596 
THE BLOOD-VASCULAR SYSTEM 
nate vein, and the remains of the thymus gland; behind, it lies on the trachea, 
oesophagus, thoracic duct, and the left recurrent laryngeal nerve. Internally, it 
is in relation with the innominate artery, inferior thyroid veins and remains of the 
thymus gland; externally, with the left pneumogastric nerve, left pleura, and left 
lung. The left subclavian artery is posterior and slightly external to it. 
Plan of the Relations of the Left Common Carotid. 
Thoracic Portion. 
In front. 
Sternum. 
Sterno-hyoid and Sterno-thyroid muscles. 
Left innominate vein. 
Remains of the thymus gland. 
Internally. 
Innominate artery. 
Inferior thyroid veins. 
Remains of the thymus gland 
'Left Common 
Carotid. 
Thoracic 
Portion. 
Externally. 
Left pneumogastric nerve. 
Left pleura and lung. 
Left subclavian artery. 
Behind. 
Trachea. 
(Esophagus. 
Thoracic duct. 
Left recurrent laryngeal nerve. 
In the neck the two common carotids resemble each other so closely that one 
description will apply to both. Each vessel passes obliquely upward from behind 
the sterno-clavicular articulation to a level with the upper border of the thyroid 
cartilage, opposite the fourth cervical vertebra, where it divides into the external 
and internal carotid; these names being derived from the distribution of the arteries 
to the external parts of the head and face and to the internal parts of the cranium 
and orbit respectively. 
At the lower part of the neck the two common carotid arteries are separated 
from each other by a small interval, which contains the trachea; but at the upper 
part, the thyroid body, the larynx and pharynx project forward between the 
two vessels, and give the appearance of their being placed farther back in this 
situation. The common carotid artery is contained in a sheath derived from the 
deep cervical fascia, which also encloses the internal jugular vein and pneumo- 
gastric nerve, the vein lying on the outer side of the artery, and the nerve between 
the artery and vein, on a plane posterior to both. On opening the sheath these 
three structures are seen to be separated from one another, each being enclosed in 
a separate fibrous investment. 
Relations.-At the lower part of the neck the common carotid artery is very 
deeply seated, being covered by the integument, superficial fascia, Platysma, and 
deep cervical fascia, the Sterno-mastoid, Sterno-hyoid, and Sterno-thyroid muscles, 
and by the Omo-hyoid, opposite the cricoid cartilage; but in the upper part of its 
course, near its termination, it is more superficial, being covered merely by the 
integument, the superficial fascia, Platysma, deep cervical fascia, and inner margin 
of the Sterno-mastoid, and, when the latter is drawn backward, it is seen to be 
contained in a triangular space, bounded behind by the Sterno-mastoid, above by 
the posterior belly of the Digastric, and below by the anterior belly of the Omo- 
hyoid. This part of the artery is crossed obliquely, from within outward, by the 
sterno-mastoid artery; it is crossed also by the superior and middle thyroid veins, 
which terminate in the internal jugular; and, descending on its sheath in front, is 
seen the descendens hypoglossi nerve, this filament being joined by one or two 
branches from the cervical nerves, which cross the vessel from without inward. THE COMMON CAROTID ARTERY 
597 
Sometimes the descendens hypoglossi is contained within the sheath. The middle 
thyroid vein crosses the artery about its middle, and the anterior jugular vein below; 
the latter, however, is separated from the artery by the Sterno-hyoid and Sterno- 
thyroid muscles. Behind, the artery is separated from the transverse processes of 
the vertebrie by the Longus colli and Rectus capitis anticus major muscles, the 
sympathetic nerve being interposed between it and the muscles. The recurrent 
Hypo- 
glossal N. 
Crico-thyroid 
artery. 
Fig. 393.-Plan of the 
branches of the external 
carotid. 
Fig. 392.-Surgical anatomy of the arteries of the neck, showing the carotid and subclavian arteries. 
laryngeal nerve and inferior thyroid artery cross behind the vessel at its lower part. 
Internally, it is in relation with the trachea and thyroid gland, the latter overlapping 
it> the inferior thyroid artery and recurrent laryngeal nerve being interposed: 
higher up, with the larynx and pharynx. On its outer side are placed the internal 
jugular vein and pneumogastric nerve. At the lower part of the neck the internal 
jugular vein on the right side diverges from the artery, but on the left side it 598 
THE BLOOD -VASCULAR SYSTEM 
approaches it, and often overlaps its lower part. This is an important fact to bear 
in mind during the performance of any operation on the lower part of the left 
common carotid artery. In this region the relation which the right and left recur- 
rent laryngeal nerves bear to the arteries is not identical. The left recurrent laryn- 
geal nerve lies behind the thoracic portion of the left common carotid artery and 
internal to the cervical portion of the vessel. The right nerve passes obliquely 
upward and inward behind the right common carotid to reach its inner side. 
Plan of the Relations of the Common Carotid Artery. 
Integument and superficial fascia. 
Deep cervical fascia. 
Platysma. 
Sterno-mastoid. 
Sterno-hyoid. 
Sterno-thyroid. 
In front. 
Omo-hyoid. 
Descendens and Communicans hypoglossi 
nerves. 
Sterno-mastoid artery. 
Superior and middle thyroid veins. 
Anterior jugular vein. 
Externally. 
Internal jugular vein. 
Pneumogastric nerve. 
Internally. 
Trachea. 
Thyroid gland. 
Recurrent laryngeal nerve. 
Inferior thyroid artery. 
Larynx. 
Pharynx. 
Common 
Carotid. 
Behind. 
Longus colli. 
Rectus capitis anticus major. 
Sympathetic nerve. 
Inferior thyroid artery. 
Recurrent laryngeal nerve. 
Peculiarities as to Origin.-The right common carotid may arise above or below the upper 
border of the sterno-clavicular articulation. This variation occurs in one out of about eight 
cases and a half, and the origin is more frequently below than above; or the artery may arise 
as a separate branch from the arch of the aorta or in conjunction with the left carotid. The 
lejt common carotid varies more frequently in its origin than the right. In the majority of abnor- 
mal cases it arises with the innominate artery, or, if the innominate artery is absent, the two 
carotids arise usually by a single trunk. It rarely joins with the left subclavian, except in cases 
of transposition of the arch. 
Peculiarities as to Point of Division.-The most important peculiarities of this vessel, in 
a surgical point of view, relate to its place of division in the neck. In the majority of abnormal 
cases this occurs higher than usual, the artery dividing into two branches opposite the hyoid 
bone, or even higher; more rarely it occurs below, opposite the middle of the larynx or the lower 
border of the cricoid cartilage; and one case is related by Morgagni where the common carotid, 
only an inch and a half in length, divided at the root of the neck. Very rarely the common 
carotid ascends in the neck without any subdivision, the internal carotid being wanting; and 
in a few cases the common carotid has been found to be absent, the external and internal carotids 
arising directly from the arch of the aorta. This peculiarity existed on both sides in some instances, 
on one side in others. 
Occasional Branches.-The common carotid usually gives off no branch previous to its 
bifurcation; but it occasionally gives origin to the superior thyroid or its laryngeal branch, the 
ascending pharyngeal, the inferior thyroid, or, more rarely, the vertebral artery. 
Surface Marking.-The carotid arteries are covered throughout their entire extent by the 
Sterno-mastoid muscle, but their course does not correspond- to the anterior border of the muscle, 
which passes in a somewhat curved direction from the mastoid process to the sterno-clavicular 
joint. The course of the artery is indicated more exactly by a line drawn from the sternal end 
of the clavicle below, to a point midway between the angle of the jaw and the mastoid process 
above. That portion of the line below the level of the upper border of the thyroid cartilage 
would represent the course of the vessel. 
Surgical Anatomy.-The operation of tying the common carotid artery may be necessary 
in a case of wound of that vessel or its branches, in aneurism, or in a case of pulsating tumor of 
the orbit or skull. If the wound involves the trunk of the common carotid, it will be necessary 
to tie the artery through the wound above and below the wounded part. If the wound is too small 
to admit of safe and rapid work it must be enlarged. In cases of aneurism, or where one of THE COMMON CAROTID ARTERY 
599 
the branches of the common carotid is wounded in an inaccessible situation, it may be judged 
necessary to tie the trunk. In such cases the whole of the artery is accessible, and any part may 
be tied except close to either end. When the case is such as to allow of a choice being made, 
the lower part of the carotid should never be selected as the spot upon which to place a ligature, 
for not only is the artery in this situation placed very deeply in the neck, but it is covered by 
three layers of muscles, and, on the left side, in the great majority of cases, the internal jugular 
vein passes obliquely in front of it. Neither should the upper end be selected, for here the 
superior thyroid vein and its tributaries would give rise to very considerable difficulty in the appli- 
cation of a ligature. The point most favorable for the operation is that part of the vessel which 
is at the level of the cricoid cartilage. It occasionally happens that the carotid artery bifurcates 
below its usual position: if the artery be exposed at its point of bifurcation, both divisions of 
the vessel should be tied near their origin, in preference to tying the trunk of the artery near its 
termination; and if, in consequence of the entire absence of the common carotid or from its 
early division, two arteries, the external and internal carotids, are met with, the ligature should 
be placed on that vessel which is found on compression to be connected with the disease. 
Ligation of the Carotid at the Level of the Cricoid Cartilage (Ligation in the Triangle of 
Election).-The triangle of election is bounded posteriorly by the anterior edge of the sterno- 
cleido-mastoid; is bounded above by the posterior belly of the digastric; is bounded below by the 
anterior belly of the omohyoid. In this operation the direction of the vessel and the inner 
margin of the Sterno-mastoid are the chief guides to its performance. The patient should be 
placed on his back with the head thrown back and turned slightly to the opposite side: an 
incision is to be made, three inches long, in the direction of the anterior border of the Sterno- 
mastoid, so that the centre corresponds to the level of the cricoid cartilage; after dividing the 
integument, superficial fascia, and Platysma, the deep fascia must be cut through on a director, 
so as to avoid wounding numerous small veins that are usually found beneath. The head 
may now be brought forward so as to relax the parts somewhat, and the margins of the wound 
are held asunder by retractors. The descendens hypoglossi nerve may now be exposed, and must 
be avoided, and, the sheath of the vessel having been raised by forceps, is to be opened to a small 
extent over the artery at its inner side. The internal jugular vein may present itself alternately 
distended and relaxed; this should be compressed both above and below, and drawn outward, 
in order to facilitate the operation. The aneurism needle is passed from the outside, care 
being taken to keep the needle in close contact with the artery, and thus avoid the risk of 
injuring the internal jugular vein or including the vagus nerve. Before the ligature is tied it 
should be ascertained that nothing but the artery is included in it. 
Ligation of the Common Carotid at the Lower Part of the Neck (Ligation in the Triangle 
of Necessity).-The triangle of necessity is bounded above by the anterior belly of the omo- 
hyoid; is bounded behind by the anterior margin of the sterno-cleido-mastoid; is bounded 
in front by the mid-line of the neck. This operation is sometimes required in cases of 
aneurism of the upper part of the carotid, especially if the sac is of large size. It is best 
performed by dividing the sternal origin of the Sterno-mastoid muscle, but may be done 
in some cases, if the aneurism is not of very large size, by an incision along the anterior 
border of the Sterno-mastoid, extending down to the sterno-clavicular articulation, and by 
then retracting the muscle. The easiest and best plan, however, is to make an incision two 
or three inches long down the lower part of the anterior border of the Sterno-mastoid muscle 
to the sterno-clavicular joint, and a second incision, starting from the termination of the first, 
along the upper border of the clavicle for about two inches. This incision is made through the 
superficial and deep fascia, and the sternal origin of the muscle is exposed. This is to be divided 
on a director, and turned up, with the superficial structures, as a triangular flap. Some loose 
connective tissue is to be divided or torn through, and the outer border of the Sterno-hyoid 
muscle exposed. In doing this care must be taken not to wound the anterior jugular vein, which 
crosses the muscle to reach the external jugular or subclavian vein. The Sterno-hyoid, and with 
it the Sterno-thyroid, are to be drawn inward by means of a retractor, and the sheath of the 
vessel is exposed. This must be opened with great care on its inner or tracheal side, so as to 
avoid the internal jugular vein. This is especially necessary on the left side, where the artery 
is commonly overlapped by the vein. On the right side there is usually an interval between the 
artery and the vein, and not the same risk of wounding the latter. 
The common carotid artery, being a long vessel without any branches, is particularly suitable 
for the performance of Brasdor's operation for the cure of an aneurism of the lower part of the 
vessel. Brasdor's procedure consists in ligaturing the artery on the distal side of the aneurism, 
and in the case of the common carotid there are no branches given off from the vessel between 
the aneurism and the site of the ligature; hence the flow of blood through the sac of the aneurism 
is diminished and cure takes place in the usual way, by the deposit of laminated fibrin. 
Collateral Circulation.-After ligature of the common carotid the collateral circulation 
can be perfectly established, by the free communication which exists between the carotid arteries 
of opposite sides, both without and within the cranium, and by enlargement of the branches of 
the subclavian artery on the side corresponding to that on which the vessel has been tied-the 600 
THE BLOOD-VASCULAR SYSTEM 
chief communication outside the skull taking place between the superior thyroid from the 
external carotid and the inferior thyroid from the subclavian, the profunda cervicis from the 
subclavian and the superior intercostal with the arteria princeps cervicis of the occipital; 
the vertebral taking the place of the internal carotid within the cranium. 
Sir A. Cooper had an opportunity of dissecting, thirteen years after the operation, the case 
in which he first successfully tied the common carotid (the second case in which he performed 
the operation).1 The injection, however, does not seem to have been a successful one. It showed 
merely that the arteries at the base of the brain (circle of Willis) were much enlarged on the 
side of the tied artery, and that the anastomosis between the branches of the external carotid on 
the affected side and those of the same artery on the sound side was free, so that the external 
carotid was pervious throughout. 
The Intercarotid Body (carotid gland, retrocarotid corpuscle) (see the Ductless 
Glands). 
The External Carotid Artery (A. Carotis Externa) (Figs. 392, 393, 394). 
The external carotid artery commences opposite the upper border of the thyroid 
cartilage, and, taking a slightly curved course, passes upward and forward, and 
then inclines backward to the space between the neck of the condyle of the lower 
jaw and the external meatus, where it divides into the superficial temporal and 
internal maxillary arteries. It rapidly diminishes in size in its course up the 
neck, owing to the number and large size of the branches given off from it. In 
the child it is somewhat smaller than the internal carotid, but in the adult the 
two vessels are of nearly equal size. At its commencement this artery is more 
superficial, and placed nearer the middle line than the internal carotid, and is 
contained in the triangular space bounded by the Sterno-mastoid behind, the 
anterior belly of the Omo-hyoid below, and the posterior belly of the Digastric 
and the Stylo-hyoid above. 
Relations.-It is covered by the skin, superficial fascia, Platysma, deep fascia 
and anterior margin of the Sterno-mastoid, and is crossed by the hypoglossal nerve, 
and by the lingual and facial veins; it is afterward crossed by the Digastric and 
Stylo-hyoid muscles, and higher up passes deeply into the substance of the parotid 
gland, where it lies beneath the facial nerve and the junction of the temporal and 
internal maxillary veins. Internally is the hyoid bone, wall of the pharynx, the 
superior laryngeal nerve, and the ramus of the jaw, from which it is separated by 
a portion of the parotid gland. Externally, in the lower part of its course, is the 
internal carotid artery. Behind it, near its origin, is the superior laryngeal nerve; 
and higher up, it is separated from the internal carotid by the Stylo-glossus and 
Stylo-pharyngeus muscles, the glosso-pharyngeal nerve, and part of the parotid 
gland. 
Plan of the Relations of the External Carotid. 
In front. 
Skin, superficial fascia. 
Platysma and deep fascia. 
Anterior border of Sterno-mastoid. 
Hypoglossal nerve. 
Lingual and facial veins. 
Digastric and Stylo-hyoid muscles. 
Parotid gland with facial nerve and temporo-maxillary vein 
in its substance. 
Internally. 
Hyoid bone. 
Pharynx. 
Superior laryngeal nerve 
Parotid gland. 
Ramus of jaw. 
Externally. 
Internal carotid artery. 
External 
Carotid. 
1 Guy's Hospital Reports, i., 56. THE EXTERNAL CAROTID ARTERY 
601 
Superior laryngeal nerve. 
Stylo-glossus. 
Stylo-pharyngeus. 
Glosso-pharyngeal nerve. 
Parotid gland. 
Behind. 
Surface Marking.-The position of the external carotid artery may be marked out with 
sufficient accuracy by a line drawn from the front of the meatus of the external ear to the side 
of the cricoid cartilage, slightly arching the line forward. 
Surgical Anatomy.-The application of a ligature to the external carotid may be required 
in case of wounds of this vessel, or of its branches when these cannot be tied, and in some cases 
of pulsating tumor of the scalp or face. The operation has not received the attention which it 
deserves, owing to the fear which surgeons have entertained of secondary hemorrhage, on account 
of the number of branches given off from the vessel. This fear, however, has been shown by 
Mr. Cripps not to be well founded.1 Ligation is often very useful as a means of prevent- 
ing excessive hemorrhage in operations about the face, jaws, and mouth. It is sometimes 
employed with the hope of lessening the growth of tumors by cutting off the blood supply, but 
ligation is useless for this purpose. Ligation of one external carotid artery arrests the circu- 
lation for only a brief period, and within a very few' days the circulation is practically freely 
re-established. This result is seen to be inevitable when we recall the numerous branches of the 
external carotid, their free anastomoses, and the fact that a very great number of extremely minute 
vessels in the middle line join the external carotid system of one side to that of the other side. 
Robert H. M. Dawbarn points out that ligation of both external carotids produces only temporary 
anaemia, for "inside of a week or ten days thereafter the pulse can again be felt in the temporals and 
facials upon both sides."2 Dawbarn points out that even after excision of the external carotids, 
with separate ligation of each of the eight branches, blood can still reach the nose, tongue, etc., 
from outside systems by twenty-nine distinct routes. Whereas ligation of even both carotids will 
not prevent the growth of a malignant tumor, excision of each external carotid, with separate 
control of its eight branches, will sometimes prove of great value in retarding the progress of a 
growth. It " starves " the growth and may cause it to shrink (Daw7barn's operation). To tie the 
external carotid near its origin, below the point where it is crossed by the Digastric, an incision 
about three inches in length should be made along the margin of the Sterno-mastoid, from the 
angle of the jaw to the upper border of the thyroid cartilage. The ligature should be applied 
between the lingual and superior thyroid branches. To tie the vessel above the Digastric, 
between it and the parotid gland, an incision should be made, from the lobe of the ear to the 
great cornu of the os hyoides, dividing successfully the skin, Platysma, and fascia. By drawing 
the Sterno-mastoid outward, the posterior belly of the Digastric and Stylo-hyoid muscles down- 
ward, and separating them from the parotid gland, the vessel will be exposed, and a ligature may 
be applied to it. The circulation is at once re-established by the free communication between 
most of the large branches of the artery (facial, lingual, superior thyroid, occipital) and the corre- 
sponding arteries of the opposite side and by the anastomosis of its branches with those of the 
internal carotid, and of the occipital with the branches of the subclavian, etc. 
Branches.- The external carotid artery gives off eight branches, which, for 
convenience of description, may be divided into four sets. (See Fig. 393, Plan of 
the Branches.) 
Anterior. 
Superior Thyroid. 
Ungual. 
Facial. 
Posterior. 
Occipital. 
Posterior Auric- 
ular. 
Ascending. 
Ascending Phar- 
yngeal. 
Terminal. 
Superficial Temporal. 
Internal Maxillary. 
The student is here reminded that many variations are met with in the number, 
origin, and course of these branches in different subjects; but the above arrange- 
ment is that which is found in the great majority of cases. 
The Superior Thyroid Artery (a. thyreoidea superior} (Figs. 392, 393, and 3( 6) 
is the first branch given off from the external carotid, being derived from that vessel 
just below the great cornu of the hyoid bone. At its commencement it is quite 
superficial, being covered by the integument, fascia, and Platysma, and is contained 
1 Med.-Chir Trans., Ixi., 229. 2 The Treatment of Certain Malignant Growths. THE BLOOD-VASCULAR SYSTEM 
602 
in the triangular space bounded by the Sterno-mastoid, Digastric, and Omo-hyoid 
muscles. After running upward and inward for a short distance, it curves down- 
ward and forward, in an arched and tortuous manner, to the upper part of the 
thyroid gland, passing beneath the Omo-hyoid, Sterno-hyoid, and Sterno-thyroid 
muscles, and supplying them. It distributes numerous branches to the upper part 
of the gland, anastomosing with its fellow of the opposite side and with the 
inferior thyroid arteries. The terminal branches supplying the gland are generally 
two in number: one, the largest, the anterior branch (ramus anterior), descends 
at the anterior border of the lateral lobe of the gland, reaches the upper border 
of the isthmus, and then passes in the substance of the isthmus to the middle 
line of the neck, where it anastomoses with the corresponding artery of the 
opposite side: the posterior branch (ramus posterior) descends along the posterior 
border of the lateral lobe of the gland, the anterior and posterior branches 
anastomose with each other and with blanches of the inferior thyroid, and both 
of them send branches to the thyroid gland (rami glandidares). Besides the 
arteries distributed to the muscles by which it is covered and to the substance 
of the gland, the branches of the superior thyroid are the following: 
Hyoid. 
Superficial Descending Branch (Sterno-mastoid). 
Superior Laryngeal. 
Crico-thyroid. 
The Hyoid or Infra-hyoid (ramus hyoideus) is a small branch which runs along 
the lower border of the os hyoides beneath the Thyro-hyoid muscle; after sup- 
plying the muscles connected to that bone, it forms an arch, by anastomosing 
with the vessel of the opposite side. 
The Superficial Descending or Sterno-mastoid Branch (ramus sternocleidomas- 
toideus) runs downward and outward across the sheath of the common carotid 
artery, and supplies the Sterno-mastoid and neighboring muscles and integument. 
There is frequently a separate branch from the external carotid distributed to the 
Sterno-mastoid muscle. 
The Superior Laryngeal (a. laryngea superior), larger than either of the preceding, 
accompanies the internal laryngeal nerve, beneath the Thyro-hyoid muscle: it 
pierces the thyro-hyoid membrane, and supplies the muscles, mucous membrane, 
and glands of the larynx, anastomosing with the branch from the opposite 
side. 
The Crico-thyroid (ramus cricothyreoideus) is a small branch which runs trans- 
versely across the crico-thyroid membrane, communicating with the artery of the 
opposite side. 
Arteries of the Thyroid Gland.-The thyroid gland is supplied by the two 
superior thyroids from the external carotid; the two inferior thyroids from the 
subclavian, and sometimes also by the thyreoidea ima from the innominate. 
The superior thyroid joins the gland at the summit of the upper horn, passes 
down the posterior surface of the gland toward the inner surface of the upper horn, 
comes forward to the anterior margin of the inner surface, descends to the isthmus, 
and on the superior border of the isthmus anastomoses with the artery from the 
other side. The superior thyroid artery sends numerous branches across the 
anterior surface of the gland. 
The inferior thyroid artery is larger than the superior artery. It passes to 
the posterior surface of the gland and divides into branches. Some of the branches 
enter the hilus; others track across the posterior surface of the gland. The inferior 
thyroid artery is close to the recurrent laryngeal nerve. The artery, as a rule, 
passes behind the nerve before it divides into branches. It may divide first and 
then one or two branches may be in front of the nerve. In unusual cases the 
artery before division is in front of the nerve, or all the branches are in front.1 
1 Berry. Diseases of the Thyroid Gland. THE EXTERNAL CAROTID ARTERY 
603 
The thyreoidea ima passes to the lower portion of the gland. Berry points out 
that the thyroid arteries communicate very freely with each other; only the small 
branches pass into the interior of the gland; the larger branches "ramify on the 
surface of the gland, just beneath the capsule."1 
Surgical Anatomy.-The superior thyroid, or one of its branches, is often divided in cases 
of cut throat, giving rise to considerable hemorrhage. In such cases the artery should be secured, 
the wound being enlarged for that purpose, if necessary. The operation may be easily per- 
formed, the position of the artery being very superficial, and the only structures of importance 
covering it being a few small veins. The operation of tying the superior thyroid artery to lessen 
the size of a bronchocele has been performed in numerous instances with partial or temporary 
success. When, however, the collateral circulation between this vessel and the artery of the 
opposite side, and the inferior thyroid, is completely re-established, the tumor usually regains 
its former size, and hence the operation has been given up, especially as better results are 
obtained by other means. Both thyroid arteries on the same side, and indeed all the four 
thyroid arteries, have been tied in enlarged thyroid. The superior and inferior thyroid arteries 
of the involved side are ligated before extirpating a goitrous lobe of the thyroid. 
The position of the superficial descending branch is of importance in connection with the 
operation of ligation of the common carotid artery. It crosses and lies on the sheath of this 
vessel, and may chance to be wounded in opening the sheath. The position of the crico-thyroid 
branch should be remembered, as it may prove the source of troublesome hemorrhage during 
the operation of laryngotomy. In performing the operation of quick laryngotomy the crico- 
thyroid membrane should be incised transversely in order to avoid this vessel. 
The Lingual Artery (a. lingualis) (Figs. 392 and 393) arises from the external 
carotid between the superior thyroid and facial; it first runs obliquely upward 
and inward to the great cornu of the hyoid bone; it then curves downward and 
forward, forming a loop which is crossed by the hypoglossal nerve, and, passing 
beneath the Digastric and Stylo-hyoid muscles, it runs horizontally forward, 
beneath the Hyo-glossus, and finally, ascending almost perpendicularly to the 
tongue, turns forward on its under surface as far as the tip, under the name of 
the ranine artery. 
Relations.-Its first, or oblique, portion is superficial, being contained in the 
same triangular space as the superior thyroid artery, resting upon the middle con- 
strictor of the pharynx, and covered by the Platysma and fascia of the neck. Its 
second, or curved, portion also lies upon the middle constrictor, being covered at 
first by the tendon of the Digastric and the Stylo-hyoid muscle, and afterward by 
the Hyo-glossus, the latter muscle separating it from the hypoglossal nerve. Its 
third, or horizontal, portion lies between the Hyo-glossus and Genio-hyo-glossus 
muscles. The fourth, or terminal, part, under the name of the ranine, runs along 
the under surface of the tongue to its tip: it is very superficial, being covered 
only by the mucous membrane, and rests on the Lingualis on the outer side of 
the Genio-hyo-glossus. The hypoglossal nerve crosses the lingual artery, and then 
becomes separated from it, in the second part of its course, by the Hyo-glossus 
muscle. 
Branches.-The branches of the lingual artery are-the 
Hyoid. 
Dorsalis Linguae. 
Sublingual. 
Ranine. 
The Hyoid or Supra-hyoid Branch (ramus hyoideus) runs along the upper border 
of the hyoid bone, supplying the muscles attached to it and anastomosing with 
its fellow of the opposite side. 
The Dorsalis Linguae (ramus dorsalis linguae) (Fig. 445) arises from the lingual 
artery beneath the Hyo-glossus muscle (which, in the figure, has been partly cut 
away, to show the vessel); it ascends to the dorsum of the tongue, and supplies the 
mucous membrane, the tonsil, soft palate, and epiglottis, anastomosing with its 
1 Berry. Diseases of the Thyroid Gland 604 
THE BLOOD-VASCULAR SYSTEM 
fellow from the opposite side. This artery is frequently represented by two or 
three small branches. 
The Sublingual (a. sublingualis), which may be described as a branch of bifur- 
cation of the lingual artery, arises at the anterior margin of the Hyo-glossus muscle, 
and runs forward between the Genio-hyo-glossus and the sublingual gland. It 
supplies the substance of the gland, giving branches to the Mylo-hyoid and 
neighboring muscles, the mucous membrane of the mouth and gums. One 
branch runs behind the alveolar process of the lower jaw in the substance of the 
gum to anastomose with a similar artery from the other side. 
The Ranine or Deep Lingual (a. profunda linguae) may be regarded as the other 
branch of bifurcation. It is usually described as the continuation of the lingual 
artery; it runs along the under surface of the tongue, resting on the Inferior 
lingualis, and covered by the mucous membrane of the mouth; it lies on the outer 
side of the Genio-hyo-glossus, accompanied by the lingual nerve. On arriving 
at the tip of the tongue it is said to anastomose with the artery of the opposite 
side, but this is denied by HyrtL These vessels in the mouth are placed one on 
each side of the fraenum. 
Surgical Anatomy.-The lingual artery may be divided near its origin in cases of cut throat, 
a complication that not unfrequently happens in this class of wounds; or severe hemorrhage 
which cannot be restrained by ordinary means may ensue from a wound or deep ulcer of the 
tongue. In the former case the primary wound may be enlarged if necessary, and the bleeding 
vessels secured. In the latter case it has been suggested that the lingual artery should be tied 
near its origin. Ligature of the lingual artery is also occasionally practised, as a palliative measure, 
in cases of cancer of the tongue, in order to check the progress of the disease by starving the 
growth, and it is sometimes tied as a preliminary measure to removal of the tongue. The operation 
is a somewhat difficult one, on account of the depth of the artery, the number of important 
structures by which it is surrounded, the loose and yielding nature of the parts upon which it is 
supported, and its occasional irregularity of origin. An incision is to be made in a curved direc- 
tion from a point one finger's breadth external to the symphysis of the jaw downward to the 
cornu of the hyoid bone, and then upward to near the angle of the jaw. Care must be taken not 
to carry this incision too far backward, for fear of endangering the facial vein. In the first 
incision the skin, superficial fascia, and Platysma will be divided, and the deep fascia exposed. 
The deep fascia is then to be incised and the submaxillary gland exposed and pulled upward by 
retractors. A triangular space is now exposed, Lesser s triangle, bounded internally by the pos- 
terior border of the Mylo-hyoid muscle: below and externally, by the tendon of the Digastric; 
and above, by the hypoglossal nerve. The floor of the space is formed by the Hyo-glossus muscle, 
beneath which the artery lies. The fibres of this muscle are now to be cut through horizontally 
and the vessel exposed, care being taken, while near the vessel, not to open the pharynx. 
Troublesome hemorrhage may occur in the division of the fraenum in children if the ranine 
arteries, which lie on each side of it, are wounded. The student should remember that the opera- 
tion is always to be performed with a pair of blunt-pointed scissors, and the mucous membrane 
only is to be divided by a very superficial cut, which cannot endanger any vessel. The scissors, 
also, should be directed away from the tongue. Any further liberation of the tongue which may 
be necessary can be effected by tearing. 
The Facial or External Maxillary Artery (a. maxillaris externa) (Figs. 392, 
393, 394, and 395) arises a little above the lingual, and passes obliquely upward, 
beneath the Digastric and Stylo-hyoid muscles, and frequently beneath the hypo- 
glossal nerve; it now runs forward under cover of the body of the lower jaw, lodged 
in a groove on the posterior surface of the submaxillary gland; this may be called 
the cervical part of the artery. It then curves upward over the body of the jaw 
at the anterior inferior angle of the Masseter muscle; passes forward and upward 
across the cheek to the angle of the mouth, then upward along the side of the nose, 
and terminates at the inner canthus of the eye, under the name of the angular artery 
(a. angularis). The facial artery, both in the neck and on the face, is remarkably 
tortuous: in the former situation its tortuosity enables it to accommodate itself to 
the movements of the pharynx in deglutition, and in the latter to the movements 
of the jaw and the lips and cheeks. THE EXTERNAL CAROTID ARTERY 
605 
Relations.-In the neck its origin is superficial, being covered by the integu- 
ment, Platysma, and fascia; it then passes beneath the Digastric and Stylo-hyoid 
muscles and part of the submaxillary gland. It lies upon the middle constrictor 
of the pharynx, and is separated from the Stylo-glossus and Hyo-glossus muscles 
by a portion of the submaxillary gland. On the face, where it passes over the 
body of the lower jaw, it is comparatively superficial, lying immediately beneath 
the Platysma. In this situation its pulsation may be distinctly felt, and compres- 
sion of the vessel against the bone can be effectually made. In its course over the 
face it is covered by the integument, the fat of the cheek, and, near the angle of the 
Angular. 
Lateralis 
nasi. 
-Arteria septi nasi. 
.Superior coronary. 
Inferior coronary. 
Inferior labial. 
Fig. 394.-The arteries of the face and scalp.1 
mouth, by the Platysma, Risorius, and Zygomatic muscles. It rests on the Bucci- 
nator, the Levator anguli oris, and the Levator labii superioris (sometimes piercing 
or else passing under this last muscle). The facial vein lies to the outer side of 
the artery, and takes a more direct course across the face, where it is separated 
from the artery by a considerable interval. In the neck it lies superficial to the 
artery. The branches of the facial nerve cross the artery, and branches of the 
infraorbital nerve lie beneath it. 
Branches.-The branches of this vessel may be divided into two sets: those 
given off below the jaw (cervical), and those on the face (facial). 
1 The muscular tissue of the lips must be supposed to have been cut away, in order to show the course of the 
coronary arteries 606 
THE BLOOD-VASCULAR SYSTEM 
Cervical Branches. 
Inferior or Ascending Palatine. 
Tonsillar. 
Submaxillary. 
Submental. 
Muscular. 
Facial Branches. 
Muscular. 
Inferior Labial. 
Inferior Coronary. 
Superior Coronary. 
Lateral Nasal. 
Angular. 
The Inferior or Ascending Palatine (a. palatine ascendens) passes up between 
the Stylo-glossus and Stylo-pharyngeus to the outer side of the pharynx, along 
which it is continued between the Superior constrictor and the Internal ptery- 
goid to near the base of the skull. It supplies the neighboring muscles, the 
tonsil, and Eustachian tube, and divides, near the. Levator palati, into two 
branches: one follows the course of the Levator palati, and, winding over the 
upper border of the Superior constrictor, supplies the soft palate and the palatine 
glands, anastomosing with its fellow of the opposite side and with the posterior 
palatine branch of the internal maxillary artery; the other pierces the Superior 
constrictor and supplies the tonsil, anastomosing with the tonsillar and ascending 
pharyngeal arteries. 
The Tonsillar (ramus tonsillaris) passes up between the Internal pterygoid 
and Stylo-glossus, and then ascends along the side of the pharynx, perforating 
the Superior constrictor, to ramify in the substance of the tonsil and root of the 
tongue. 
Fig. 395.-The coronary arteries, the glands of the lips, and the nerves of the right side seen from the 
posterior surface after removal of the mucous membrane. (Poirier and Charpy.) 
The Submaxillary or Glandular Branches (rami glandulares) consist of three 01 
four large vessels, which supply the submaxillary gland, some being prolonged to 
the neighboring muscles, lymphatic glands, and integument. 
'The Submental (a. submentalis) (Fig. 392), the largest of the cervical branches, 
is given off from the facial artery just as that vessel quits the submaxillary gland: 
it runs forward upon the Mylo-hyoid muscle, just below the body of the jaw and 
beneath the Digastric; after supplying the surrounding muscles, and anastomosing 
with the sublingual artery by branches which perforate the Mylo-hyoid muscle, it 
arrives at the symphysis of the chin, where it turns over the border of the jaw and 
divides into a superficial and a deep branch; the former passes between the integu- 
ment and Depressor labii inferioris, supplies both, and anastomoses with the 
inferior labial. The deep branch passes between the latter muscle and the bone, 
supplies the lip, and anastomoses with the inferior labial and mental arteries. 
The Muscular Branches are distributed to the Internal pterygoid and Stylo- 
hyoid in the neck, and to the Masseter and Buccinator on the face. THE EXTERNAL CAROTID ARTERY 
607 
The Inferior Labial (a. labialis inferior) (Fig. 394) passes beneath the Depressor 
anguli oris, to supply the muscles and integument of the chin and lower lip, anas- 
tomosing with the inferior coronary and submental branches of the facial, and with 
the mental branch of the inferior dental artery. 
The Inferior Coronary (Figs. 394 and 395) is derived from the facial artery, near 
the angle of the mouth: it passes upward and inward beneath the depressor anguli 
oris, and, penetrating the Orbicularis oris muscle, runs in a tortudus course along 
the edge of the lower lip between this muscle and the mucous membrane, inoscu- 
lating with the artery of the opposite side. This artery supplies the labial glands, 
the mucous membrane, and muscles of the lower lip, and anastomoses with the 
inferior labial from the facial and the mental branch of the inferior dental artery. 
The Superior Coronary (a. labialis superior) (Figs. 394 and 395) is larger and more 
tortuous in its course than the preceding. It follows the same course along the 
edge of the upper lip, lying between the mucous membrane and the Orbicularis 
oris, and anastomoses with the artery of the opposite side. It supplies the textures 
of the upper lip, and gives off in its course two or three vessels which ascend to the 
nose. One, named the inferior artery of the septum, ramifies on the septum of the 
nostrils as far as the point of the nose, and there anastomoses with the naso- 
palatine artery; another, the artery of the ala, supplies the ala of the nose. 
The Lateralis Nasi is derived from the facial, as that vessel is ascending along 
the side of the nose; it supplies the ala and dorsum of the nose, anastomosing 
with its fellow, the nasal branch of the ophthalmic, the inferior artery of the sep- 
tum, the artery of the ala, and the infraorbital. 
The Angular Artery (a. angularis) is the termination of the trunk of the facial; 
it ascends to the inner angle of the orbit, embedded in the fibres of the Levator 
labii superioris alseque nasi, and accompanied by a large vein, the angular vein; 
it distributes some branches on the cheek which anastomose with the infraorbital. 
After supplying the lachrymal sac and Orbicularis palpebrarum muscle, the 
angular artery terminates by anastomosing with the nasal branch of the oph- 
thalmic artery. 
The anastomoses of the facial artery are very numerous, not only with the 
vessel of the opposite side, but, in the neck, with the sublingual branch of the 
lingual; with the ascending pharyngeal; and with the posterior palatine, a branch of 
the internal maxillary, by its inferior or ascending palatine and tonsillar branches; 
on the face, with the mental branch of the inferior dental as it emerges from the 
mental foramen, with the transverse facial, a branch of the temporal; with the 
infraorbital, a branch of the internal maxillary, and with the nasal branch of 
the ophthalmic. 
Peculiarities.-The facial arterv not unfrequentlv arises bv a common trunk with the lingual. 
This vessel is also subject to some variations in its size and in the extent to which it supplies 
the face. It occasionally terminates as the submental, and not unfrequently supplies the face 
only as high as the angle of the mouth or nose. The deficiency is then supplied by enlargement 
of one of the neighboring arteries. 
Surgical Anatomy.-The passage of the facial artery over the body of the jaw would appear 
to afford a favorable position for the application of pressure in case of hemorrhage from the 
lips, the result either of an accidental wound or during an operation; but its application is useless, 
except for a very short time, on account of the free communication of this vessel with its fellow 
and with numerous branches from different sources. In a wound involving the lip it is better 
to seize the part between the fingers, and evert it, when the bleeding vessel may be at once secured 
with pressure-forceps. In order to prevent hemorrhage in cases of removal of diseased growths 
from the part, the lip should be compressed on each side between the fingers and thumb or by 
a pair of specially devised clamp-forceps, whilst the surgeon excises the diseased part. In order 
to stop hemorrhage where the lip has been divided in an operation, it is necessary, in uniting 
the edges of the wound, to pass the sutures through the cut edges from the skin almost as deep 
as the mucous surface; by these means not only are the cut surfaces more neatly and securely 
adapted to each other, but the possibility of hemorrhage is prevented by including in the suture 608 
THE BLOOD-VASCULAR SYSTEM 
the divided artery. If the suture is, on the contrary, passed through merely the cutaneous 
portion of the wound, hemorrhage occurs into the cavity of the mouth. The student should, 
lastly, observe the relation of the angular artery to the lachrymal sac, and it will be seen that, 
as the vessel passes up along the inner margin of the orbit, it ascends on its nasal side. In 
operating for fistula lacrimalis the sac should always be opened on its outer side, in order that 
this vessel may be avoided. 
The Occipital Artery (a. occipitalis) (Figs. 392, 393, 394, and 396) arises from 
the posterior part of the external carotid, opposite the facial, near the lower margin 
Internal jugular vein. 
Occipital artery. 
Internal maxil- 
lary artery. 
Facial 
nerve. 
Lingual 
nerve. 
Inferior dental 
nerve. 
Mylo-hyoid 
k nerve. 
SUPERIOR OBLIQUE 
MUSCLE. 
COM PLEXUS. 
MUSCLE. 
Sub-occipital- 
nerve. 
Vertebral artery. 
INFERIOR OBLIQUE 
MUSCLE. 
Pneumogastric 
nerve. 
Facial artery. 
Lingual artery. 
Hypo-glossal' 
nerve. 
'External carotid 
artery. 
'Superior thyroid 
artery. 
Internal carotid- 
artery. 
STERNO-MASTOID' 
MUSCLE. 
Fig. 396.-The occipital artery and its relations. (From a dissection by Mr. Gerald S. Hughes.) 
of the Digastric muscle. At its origin it is covered by the posterior belly of the 
Digastric muscle and the Stylo-hyoid muscle, and the hypoglossal nerve winds 
around it from behind forward; higher up, it passes across the internal carotid 
artery, the internal jugular vein, and the pneumogastric and spinal accessory nerves; THE EXTERNAL CAROTID ARTERY 
609 
it then ascends to the interval between the transverse process of the atlas and the 
mastoid process of the temporal bone, and passes horizontally backward, groov- 
ing the surface of the latter bone, being covered by the Sterno-mastoid, Splenius, 
Trachelo-mastoid, and Digastric muscles, and resting upon the Rectus lateralis, the 
Superior oblique, and Complexus muscles; it then changes its course and passes 
vertically upward, pierces the fascia which connects the cranial attachment of 
the Trapezius with the Sterno-mastoid, and ascends in a tortuous course over 
the occiput, as high as the vertex, where it divides into numerous branches (rami 
occipitales). It is accompanied in the latter part of its course by the great occip- 
ital nerve, and occasionally by a cutaneous filament from the suboccipital nerve. 
Branches.-The branches given off from this vessel are- 
Muscular. 
Sterno-mastoid. 
Auricular. 
Meningeal. 
Mastoid. 
Arteria Princeps Cervicis. 
The Muscular Branches (rami musculares) supply the Digastric, Stylo-hyoid, 
Splenius, and Trachelo-mastoid muscles. 
The Sterno-mastoid (a. sternocleidomastoidea) is a large and constant branch, 
generally arising from the artery close to its commencement, but sometimes 
springing directly from the external carotid. It first passes downward and back- 
ward over the hypoglossal nerve, and enters the substance of the muscle in com- 
pany with the spinal accessory nerve. 
The Auricular Branch (ramus auricularis) supplies the back part of the concha. 
It frequently gives off a branch, which enters the skull through the mastoid 
foramen and supplies the dura mater, the diploe, and the mastoid cells. 
The Meningeal Branch (ramus meningeus) ascends with the internal jugular 
vein, and enters the skull through the foramen lacerum posterius, or through the 
anterior condyloid foramen, to supply the dura mater in the posterior fossa. 
The Mastoid Branch (ramus mastoideus) is a small vessel, by no means constant. 
It passes into the skull through the mastoid foramen and is distributed upon the 
dura mater of the posterior fossa. 
The Arteria Princeps Cervicis (ramus descendens), the largest branch of the 
occipital, descends along the back part of the neck and divides into a super- 
ficial and a deep portion. The former runs beneath the Splenius, giving off 
branches which perforate that muscle to supply the Trapezius, which anastomose 
with the superficial cervical artery, a branch of the Transversalis colli: the latter 
passes beneath the Complexus between it and the Semispinalis colli, and anasto- 
moses with branches from the vertebral and with the deep cervical artery, a 
branch of either the superior intercostal or the subclavian. The anastomosis 
between these vessels serves mainly to establish the collateral circulation after 
ligation of the carotid or subclavian artery. 
rhe cranial branches (rami occipitales) of the occipital artery are distributed 
upon the occiput; they are very tortuous, and lie between the integument and 
Occipito-frontalis, anastomosing with the artery of the opposite side, the pos- 
terior auricular and temporal arteries. They supply the back part of the 
Occipito-frontalis muscle, the integument, and pericranium. 
The Posterior Auricular Artery (a. auricularis posterior) (Figs. 392, 393, and 
394) is a small vessel which arises from the external carotid, above the Digastric 
and Stylo-hyoid muscles, opposite the apex of the styloid process. It ascends, 
under cover of the parotid gland, on the styloid process of the temporal bone, to 
the groove between the cartilage of the ear and the mastoid process, immediately 
above which it divides into its two terminal branches, the auricular and mastoid. 
Just before arriving at the mastoid process, this artery is crossed by the facial 
nerve, and has beneath it the spinal accessory nerve. 610 
THE BLOOD-VASCULAR SYSTEM 
Branches.-Besides several small branches to the Digastric, Stylo-hyoid, and 
Sterno-mastoid muscles and to the parotid gland, this vessel gives off three 
branches: 
Stylo-mastoid. Auricular. Mastoid. 
The Stylo-mastoid Branch (a. stylomastoidea) enters the stylo-mastoid foramen, 
and supplies the tympanum, mastoid cells, and semicircular canals. In the 
young subject a branch from this vessel forms, with the tympanic branch from 
the internal maxillary, a vascular circle, which surrounds the membrana tympani, 
and from which delicate vessels ramify on that membrane. It anastomoses with 
the petrosal branch of the middle meningeal artery by a twig, which enters the 
hiatus Fallopii. 
The Auricular Branch (ramus aurimdaris), one of the terminal branches, ascends 
behind the ear, beneath the Retrahens auriculam muscle, and is distributed to 
the back part of the cartilage of the ear, upon which it ramifies minutely, some 
branches curving round the margin of the fibro-cartilage, others perforating it, 
to supply its anterior surface. It anastomoses with the posterior branch nf the 
superficial temporal and also with the anterior auricular branches. 
The Mastoid Branch (ramus mastoideus) passes backward, over the Sterno- 
mastoid muscle, to the scalp above and behind the ear. It supplies the posterior 
belly of the Occipito-frontalis muscles and the scalp in this situation. It anasto- 
moses with the occipital artery. 
The Ascending Pharyngeal Artery (a. pharyngea ascendens) (Figs. 392 and 
393), the smallest branch of the external carotid, is a long, slender vessel, deeply 
seated in the neck, beneath the other branches of the external carotid and the 
Stylopharyngeus muscle. It.arises from the back part of the external carotid, near 
the commencement of that vessel, and ascends vertically between the internal 
carotid and the side of the pharynx, to the under surface of the base of the skull, 
lying on the Rectus capitis anticus major muscle. 
Branches.-Its branches may be subdivided into four sets: 
Prevertebral. Pharyngeal. Tympanic. Meningeal. 
The Prevertebral Branches are numerous small vessels which supply the Recti 
capitis antici and Longus colli muscles, the sympathetic, hypoglossal, and pneu- 
mogastric nerves, and the lymphatic glands. They anastomose with the ascending 
cervical artery. 
The Pharyngeal Branches (rami pharyngei) are three or four in number. Two 
of these descend to supply the middle and inferior Constrictors and the Stylo- 
pharyngeus, ramifying in the substance of the muscles and in the submucous 
tissue of tfie mucous membrane lining them. The largest of the pharyngeal 
branches passes inward, running upon the Superior constrictor, and sends rami- 
fications to the soft palate and tonsil, which take the place of the ascending 
palatine branch of the facial artery when that vessel is of small size. A twig 
from this branch supplies the Eustachian tube. 
The Tympanic Branch (a. tympanica inferior) is a small artery which passes 
through a minute foramen in the petrous portion of the temporal bone, in com- 
pany with the tympanic branch of the Glosso-pharyngeal nerve to supply the 
inner wall of the tympanum and anastomose with the other tympanic arteries. 
The Meningeal Branches consist of several small vessels, which pass through 
foramina in the base of the skull, to supply the dura mater. One, the posterior 
meningeal (a. meningea posterior), enters the cranium through the foramen lacerum 
posterius; a second passes through the foramen lacerum medium; and occasion- 
allv a third through the anterior condyloid foramen. They are all distributed 
to the dura mater. THE EXTERNAL CAROTID ARTERY 
Surgical Anatomy.-The ascending pharyngeal artery has been wounded from the throat, 
as in the case in which the stem of a tobacco-pipe was driven into the vessel, causing fatal hemor- 
rhage. After removal of the tonsil there is sometimes severe bleeding. This is almost never 
due to wounding of the internal carotid artery, as the latter vessel, if normally placed, is too 
far away to be damaged. The bleeding comes from branches of the ascending pharyngeal, 
tonsillar, or ascending palatine arteries. 
611 
The Superficial Temporal Artery (a. temporalis superficialis) (Fig. 392,393, and 
394), the smaller of the two terminal branches of the external carotid, appears, from 
its direction, to be the continuation of that vessel. It commences in the substance 
of the parotid gland, in the interspace between the neck of the lower jaw and the 
external auditory meatus, crosses over the posterior root of the zygoma, passes 
beneath the Attrahens auriculam muscle, lying on the temporal fascia, and 
divides, about two inches above the zygomatic arch, into two branches, an anterior 
and a posterior. This vessel is accompanied by the auriculo-temporal nerve. 
The Anterior Temporal runs tortuously upward and forward to the forehead, 
supplying the muscles, integument, and pericranium in this region, and anasto- 
moses with the supra-orbital and frontal arteries. The terminal portion of the 
anterior branch is called the frontal artery (ramus frontalis). 
The Posterior Temporal, larger than the anterior, curves upward and backward 
along the side of the head, lying superficial to the temporal fascia, and inosculates 
with its fellow of the opposite side, and with the posterior auricular and occipital 
arteries. The terminal portion of the posterior branch is named the parietal 
artery (ramus parietalis). 
The superficial temporal artery, as it crosses the zygoma, is covered by the 
Attrahens auriculam muscle, and by a dense fascia given off from the parotid 
gland: it is crossed by the temporo-facial division of the facial nerve and one or 
two veins, and is accompanied by the auriculo-temporal nerve, which lies behind 
it. Besides some twigs to the parotid gland, the articulation of the jaw, and the 
Masseter muscle. 
Branches.-The branches of the superficial temporal artery are the- 
Transverse Facial. 
Middle Temporal. 
Orbital. 
Anterior Auricular. 
The Transverse Facial Branch (a. transversa faciei) is given off from the tem- 
poral before that vessel quits the parotid gland; running forward through its 
substance, it passes transversely across the face, between Stenson's duct and 
the lower border of the zygoma, and divides on the side of the face into numerous 
branches, which supply the parotid gland, the Masseter muscle, and the integu- 
ment, anastomosing with the facial, masseteric, and infra-orbital arteries. This 
vessel rests on the Masseter, and is accompanied by one or two branches of the 
facial nerve. It is sometimes a branch of the external carotid. 
The Middle Temporal Artery (a. temporalis media) arises immediately above 
the zygomatic arch, and, perforating the temporal fascia, gives branches to the 
Temporal muscle, anastomosing with the deep temporal branches of the internal 
maxillary. It occasionally gives off an orbital branch, which runs along the upper 
border of the zygoma, between the two layers of the temporal fascia, to the outer 
angle of the orbit. This branch, which may arise directly from the superficial 
temporal artery, supplies the Orbicularis palpebrarum, and anastomoses with 
the lachrymal and palpebral branches of the ophthalmic artery. 
The Orbital Artery (a. zygomaticoorbitalis) comes off from the temporal just 
above the zygoma and is distributed to the upper orbital margin. 
The Anterior Auricular Branches (rami auriculares anteriores) are distributed 
to the anterior portion of the pinna, the lobule, and part of the external meatus, 
anastomosing with branches of the posterior auricular. 612 
THE BLOOD-VASCULAR SYSTEM 
Surgical Anatomy.-Formerly the operation of arteriotomy was performed upon this vessel 
in cases of inflammation of the eye or brain, but at the present time the operation is obsolete. 
If the student will consider the relations of the trunk of the vessels as it crosses the zygomatic 
arch, with the surrounding structures, he will observe that it is covered by a thick and dense 
fascia, crossed by one of the main divisions of the facial nerve and one or two veins, and accom- 
panied by the auriculo-temporal nerve. The anterior branch, on the contrary, is subcutaneous, 
and is a large vessel. 
The Internal Maxillary Artery (a. maxillaris interna) (Figs. 397 and 398), the 
larger of the two terminal branches of the external carotid, arises from that vessel 
opposite the neck of the condyle of the lower jaw, and is at first imbedded in the 
Incisor. 
Mental. 
Fig. 397.-The internal maxillary artery and its branches. 
Pterygopalatine 
Deep Temporal 
Vidian 
/Descending Palatine 
Middle Meningeal^ 
Small Meningeal^ 
Pterygoid 
Sphf no-palatine 
Tympanic 
Inferior Dental- 
Fig. 398.-Plan of the branches. 
substance of the parotid gland; it passes inward between the ramus of the jaw 
and the internal lateral ligament, and then upon the outer surface of the External 
pterygoid muscle to the spheno-maxillary fossa, to supply the deep structures 
of the face. For convenience of description it is divided into three portions: a 
maxillary, a pterygoid, and spheno-maxillary. 
In the first part of its course, the maxillary portion, the artery passes horizontally 
forward and inward, between the ramus of the jaw and the internal lateral liga- 
ment. The artery here lies parallel to and a little below the auriculo-temporal 
nerve; it crosses the inferior dental nerve, and lies along the lower border of the 
External pterygoid muscle. THE EXTERNAL CAROTID ARTERY 
613 
In the second part of its course, the pterygoid portion, it runs obliquely forward, 
and upward upon the outer surface of the External pterygoid muscle, being 
covered by the ramus of the lower jaw and lower part of the Temporal muscle; 
or it may pass on the inner surface of the External pterygoid muscle to reach the 
interval between its two heads, between which it passes to reach the spheno- 
maxillary fossa. 
In the third part of its course, the spheno-maxillary portion, it approaches the 
superior maxillary bone, and enters the spheno-maxillary fossa in the interval 
between the two heads of the External pterygoid muscle, where it lies in relation 
with Meckel's ganglion, and gives off its terminal branches. 
The branches of this vessel may be divided into three groups, corresponding 
with its three divisions. 
Branches of the First or Maxillary Portion (Fig. 398): 
Anterior Tympanic. 
Deep Auricular. 
Middle Meningeal. 
Small Meningeal. 
Inferior Dental. 
The Anterior Tympanic Branch (a. tympanica anterior} passes upward behind 
the articulation of the lower jaw, enters the tympanum through the Glaserian 
fissure, and ramifies upon the membrana tympani, forming a vascular circle 
around the membrane with the stylo-mastoid artery, and anastomosing with 
the Vidian and the tympanic branch from the internal carotid. 
The Deep Auricular Branch (a. auricidaris profunda} often arises in common 
with the preceding. It passes upward in the substance of the parotid gland, 
behind the temporo-maxillary articulation, pierces the cartilaginous or bony wall 
of the external auditory meatus, and supplies its cuticular lining and the outer 
surface of the membrana tympani. 
The Middle Meningeal Branch (a. meningea media} is the largest of the branches 
which supply the dura mater. It arises from the internal maxillary, between the 
internal lateral ligament and the neck of the jaw, and passes vertically upward 
between the two roots of the auriculo-temporal nerve to the foramen spinosum of 
the sphenoid bone. On entering the cranium it divides into two branches, anterior 
and posterior. The anterior branch, the larger, crosses the great ala of the sphenoid, 
and reaches the groove, or canal, in the anterior inferior angle of the parietal 
bone; it then divides into two branches which spread out between the dura mater 
and internal surface of the cranium, one passing upward over the parietal bone as 
far as the vertex, and sending rami backward to the occipital bone, the other 
passing front to the inner surface of the frontal bone. The posterior branch 
crosses the squamous portion of the temporal, and on the inner surface of the 
parietal bone divides into branches which supply the posterior part of the dura 
mater and cranium. The branches of this vessel arc distributed partly to the 
dura mater, but chiefly to the bones; they anastomose with the arteries of the 
opposite side, and with the anterior and posterior meningeal arteries. 
The middle meningeal on entering the cranium gives off the following collateral 
branches: 1. Numerous small vessels to the Gasserian ganglion, and to the dura 
mater in this situation. 2. A branch, the petrosal branch {ramus petrosus super- 
ficialis}, which enters the hiatus Fallopii, supplies the facial nerve, and anasto- 
moses with the stylo-mastoid branch of the posterior auricular artery. 3. A 
minute superior tympanic branch {a. tympanica superior}, which runs in the canal 
for the Tensor tympani muscle, and supplies this muscle and the lining mem- 
brane of the canal. 4. Orbital branches, which pass through the sphenoidal fissure, 
or through separate canals in the great wing of the sphenoid to anastomose 
with the lachrymal or other branches of the ophthalmic artery. 5. Temporal 
or anastomotic branches, which pass through foramina in the great wing of the 614 
THE BLOOD-VASCULAR SYSTEM 
sphenoid bone and anastomose in the temporal fossa with the deep temporal 
arteries. 
Surgical Anatomy.-The middle meningeal is an artery of considerable surgical importance, 
as it may be injured in fractures of the temporal region of the skull. The vessel may be ruptured 
by traumatism, even though the skull escapes fracture. Rupture of the middle meningeal artery 
will be followed by considerable hemorrhage between the bone and dura mater, which may cause 
compression of the brain and require the operation of trephining for its relief. This artery 
crosses the anterior inferior angle of the parietal bone at a point 1j inches behind the external 
angular process of the frontal bone, and If inches above the zygoma. From this point the ante- 
rior branch passes upward and slightly backward to the sagittal suture, lying about | inch to 
f inch behind the coronal suture. The posterior branch passes upward and backward over the 
squamous portion of the temporal bone. In order to expose the artery as it lies in the groove in 
the parietal bone, a semilunar incision, with its convexity upward, should be made, commencing 
an inch behind the external angular process, and carried backward for two inches. The struc- 
tures cut through are: (1) skin; (2) superficial fascia, with branches of the superficial temporal 
vessels and nerves; (3) the fascia continued down from the aponeurosis of the Occipito-frontalis; 
(4) the two layers of the temporal fascia; (5) the temporal muscle; (6) the deep temporal vessels; 
(7) the pericranium. The bone is trephined, the clot removed, and the vessel secured by 
ligatures, suture ligatures, or gauze packing. 
The Small Meningeal Branch (ramus meningeus accessorius) is sometimes derived 
from the preceding, usually from the internal maxillary. It enters the skull 
through the foramen ovale, and supplies the Gasserian ganglion and dura mater. 
The Mandibular, Inferior Alveolar or Inferior Dental Branch (a. alveolaris injerior) 
descends with the inferior dental nerve to the foramen on the inner side of the 
ramus of the jaw. It runs along the dental canal in the substance of the bone, 
accompanied by the nerve, and opposite the first bicuspid tooth divides into two 
branches, the incisor and mental; the incisor branch is continued forward beneath 
the incisor teeth as far as the symphysis, where it anastomoses with the artery 
of the opposite side; the mental branch (a. mentalis) escapes with the nerve at the 
mental foramen, supplies the structures composing the chin, and anastomoses 
with the submental, inferior labial and inferior coronary arteries. Near its origin 
the inferior dental artery gives off a lingual branch, which descends with the lingual 
(gustatory) nerve and supplies the mucous membrane of the mouth. As the 
inferior dental artery enters the foramen it gives off a mylo-hyoid branch (ramus 
mylohyoideus), which runs in the mylo-hyoid groove, and ramifies on the under 
surface of the Mylo-hyoid muscle. The dental and incisor arteries during their 
course through the substance of the bone give off a few twigs which are lost in 
the cancellous tissue, and a series of branches which correspond in number to 
the roots of the teeth: these enter the minute apertures at the extremities of the 
fangs and supply the pulp of the teeth. 
Branches of the Second or Pterygoid Portion (Fig. 398): 
Deep Temporal. 
Pterygoid. 
Masseteric. 
Buccal. 
These branches are distributed, as their names imply, to the muscles in the 
maxillary region. 
The Deep Temporal Branches, two in number, anterior (a. temporalis projunda 
anterior) and posterior (o. temporalis projunda posterior), each occupy that part 
of the temporal fossa indicated by its name. Ascending between the Temporal 
muscle and pericranium, they supply that muscle and anastomose with the middle 
temporal artery. The anterior branch communicates with the lachrymal artery 
through small branches which perforate the malar bone and great wing of the 
sphenoid. 
The Pterygoid Branches (rami pterygoidei), irregular in their number and 
origin, supply the Pterygoid muscles. THE EXTERNAL CAROTID ARTERY 
615 
The Masseteric (a. masseterica) is a small branch which passes outward, above 
the sigmoid notch of the lower jaw, to the deep surface of the Masseter muscle. 
It supplies that muscle, and anastomoses with the masseteric branches of the 
facial and with the transverse facial artery. 
The Buccal (a. buccinatoria) is a small branch which runs obliquely forward 
between the Internal pterygoid and the ramus of the jaw, to the outer surface of 
the Buccinator, to which it is distributed, anastomosing with branches of the 
facial artery. 
Branches of the Third or Spheno-maxillary Portion (Fig. 398): 
Superior Alveolar or Alveolar. 
Infraorbital. 
Descending or Posterior Palatine. 
Vidian. 
Pterygo-palatine. 
Naso- or Spheno-palatine. 
The Superior Alveolar, Alveolar or Posterior Dental Branch (a. alveolaris superior 
posterior) is given off from the internal maxillary by a common branch with the 
infraorbital, and just as the trunk of the vessel is passing into the spheno-maxillary 
fossa. Descending upon the tuberosity of the superior maxillary bone, it divides 
into numerous branches, some of which enter the posterior dental canals, to supply 
the upper molar and bicuspid teeth and the lining of the antrum, and others are 
continued forward on the alveolar process to supply the gums of the upper jaw. 
The Infraorbital (a. injraorbitalis) appears, from its direction, to .be the con- 
tinuation of the trunk of the internal maxillary. It arises from that vessel by a 
common trunk with the preceding branch, and runs along the infra-orbital 
canal with the superior maxillary nerve, emerging upon the face at the infra- 
orbital foramen, beneath the Levator labii superioris muscle. Whilst contained 
in the canal, it gives off branches which ascend into the orbit, and assist 
in supplying the Inferior rectus and Inferior oblique muscles and the lachrymal 
gland. Other branches, anterior dental (aa. alveolares superiores anteriores), descend 
through the anterior dental canals in the bone, to supply the mucous membrane of 
the antrum and the front teeth of the upper jaw. On the face, some branches pass 
upward to the inner angle of the orbit and the lachrymal sac, anastomosing with 
the angular branch of the facial artery; other branches pass inward toward the 
nose, anastomosing with the nasal branch of the ophthalmic; and other branches 
descend beneath the Levator labii superioris muscle, and anastomose with the 
transverse facial and buccal arteries. 
The four remaining branches arise from that portion of the internal maxillary 
which is contained in the spheno-maxillary fossa. 
The Descending or Posterior Palatine (a. palatina descendens) descends through 
the posterior palatine canal with the anterior palatine branch of Meckel's ganglion, 
and, emerging from the posterior palatine foramen, runs forward in a groove on 
the inner side of the alveolar border of the hard palate to the anterior palatine 
canal, where the terminal branch of the artery passes upward through the fora- 
men of Stenson to anastomose with the naso-palatine artery. Its branches are 
distributed to the gums, the mucous membrane of the hard palate, and the 
palatine glands. Whilst it is contained in the palatine canal it gives off branches 
which descend in the accessory palatine canals to supply the soft palate and 
tonsil, anastomosing with the ascending palatine artery. 
Surgical Anatomy.-The position of the descending palatine artery on the hard palate 
should be borne in mind in performing an operation for the closure of a cleft in the hard 
palate, as the vessel is in danger of being wounded, and may give rise to formidable hemor- 
rhage. In case it should be wounded it may be necessary to plug the posterior palatine 
canal in order to arrest the bleeding. This artery may bleed furiously in the operation of 
resection of the upper jaw. 616 
THE BLOOD-VASCULAR SYSTEM 
The Vidian Branch (a. canalis pterygoidei) passes backward along the Vidian 
canal with the Vidian nerve. It is' distributed to the upper part of the pharynx 
and Eustachian tube, sending a small branch into the tympanum, which anasto- 
moses with the other tympanic arteries. 
The Pterygo-palatine is a very small branch, which passes backward through 
the pterygo-palatine canal with the pharyngeal nerve, and is distributed to the 
upper part of the pharynx and Eustachian tube. 
The Naso- or Spheno-palatine (a. spheno palatind) passes through the spheno- 
palatine foramen into the cavity of the nose, at the back part of the superior 
meatus, and divides into two branches: one internal, the naso-palatine or artery of 
the septum, passes obliquely downward and forward along the septum nasi, supplies 
the mucous membrane, and anastomoses in front with the terminal branch of the 
descending palatine and the inferior artery of the septum, which is a branch 
of the superior coronary. The external branches, two or three in number, supply 
the mucous membrane covering the lateral wall of the nose, the antrum, and 
the ethmoid and sphenoid cells. 
SURGICAL ANATOMY OF THE TRIANGLES OF THE NECK 
(Fig. 269). 
The student having considered the relative anatomy of the large arteries of the 
neck and their branches, and the relations they bear to the veins and nerves, should 
now examine these structures collectively, as they present themselves in certain 
regions of the neck, in each of which important operations are constantly being 
performed. 
The side of the neck presents a somewhat quadrilateral outline, limited, above. 
by the lower border of the body of the jaw, and an imaginary line extending from 
the angle of the jaw to the mastoid process; belote, by the prominent upper border 
of the clavicle; in front, by the median line of the neck; behind, by the anterior 
margin of the Trapezius muscle. This space is subdivided into two large triangles 
by the Sterno-mastoid muscle, which passes obliquely across the neck, from the 
sternum and clavicle below to the mastoid process above. The triangular space 
in front of this muscle is called the anterior triangle; and that behind it, the poste- 
rior triangle. 
Anterior Triangle of the Neck.-The anterior triangle is bounded in front, 
by an imaginary line extending from the chin to the sternum; behind, by the 
anterior margin of the Sterno-mastoid; its base, directed upward, is formed by 
the lower border of the body of the jaw and an imaginary line extending from 
the angle of the jaw to the mastoid process; its apex is below, at the sternum. 
This space is subdivided into three smaller triangles by the Digastric muscle 
above and the anterior belly of the Omo-hyoid below.- These smaller triangles 
are named, from below upward, the inferior carotid, the superior carotid, and the 
submaxillary triangle. 
The Inferior Carotid Triangle or the Triangle of Necessity is bounded, in front, 
by the median line of the neck; behind, by the anterior margin of the Sterno- 
mastoid; above, by the anterior belly of the Omo-hyoid; and is covered by the 
integument, superficial fascia, Platysma, and deep fascia, ramifying between 
which are some of the descending branches of the superficial cervical plexus. 
Beneath these superficial structures are the Sterno-hyoid and Sterno-thyroid 
muscles, which, together with the anterior margin of the Sterno-mastoid, conceal 
the lower part of the common carotid artery.1 The floor of this triangle is formed 
1 Therefore the common carotid artery and internal jugular vein are not, strictly speaking, contained in this 
triangle, since they are covered by the Sterno-mastoid muscle, that is to say, lie behind the anterior border of 
that muscle, which forms the posterior border of the triangle. But, as they lie very close to the structures 
which are really contained in the triangle, and whose position it is essential to remember in operating on this 
part of the artery, it has seemed expedient to study the relations of all these parts together.-Ed. of 15th 
English edition. SURGICAL ANATOMY OF THE T1UANGLES OF THE NECK 
617 
by the Longus colli muscle below and by the Scalenus anticus muscle above, between 
which muscles the vertebral artery and vein will be found passing into the foramen 
of the transverse process of the sixth cervical vertebra. A small portion of the origin 
of the Rectus capitis anticus major may also be seen on the floor of the space. 
The common carotid artery is enclosed within its sheath, together with the 
internal jugular vein and pneumogastric nerve; the vein lying on the outer side 
of the artery on the right side of the neck, but overlapping it below on the left side; 
the nerve lying between the artery and vein, on a plane posterior to both. In 
front of the sheath are a few filaments descending from the loop of communica- 
tion between the Descendens and communicans hypoglossi; behind the sheath 
are seen the inferior thyroid artery, the recurrent laryngeal nerve, and the sym- 
pathetic nerve; and on its inner side, the trachea, the thyroid gland-much more 
prominent in the female than in the male-and the lower part of the larynx. By 
cutting into the upper part of this space and slightly displacing the Sterno-mastoid 
muscle the common carotid artery may be tied below the Omo-hyoid muscle. 
The Superior Carotid Triangle or the Triangle of Election is bounded, behind, 
by the Sterno-mastoid; below, by the anterior belly of the Omo-hyoid; and 
above, by the posterior belly of the Digastric muscle. It is covered by the 
integument, superficial fascia, Platysma, and deep fascia, ramifying between 
which are branches of the facial and superficial cervical nerves. Its floor is 
formed by parts of the Thyro-hyoid and Hyo-glossus muscles, and the Inferior 
and Middle constrictor muscles of the pharynx. This space, when dissected, 
is seen to contain the upper part of the common carotid artery, which bifur- 
cates opposite the upper border of the thyroid cartilage into the external and 
internal carotid. These vessels are occasionally somewhat concealed from view 
by the anterior margin of the Sterno-mastoid muscle, which overlaps them. 
The external and internal carotid lie side by side, the external being the more 
anterior of the two. The following branches of the external carotid are also 
met with in this space: the superior thyroid, running forward and downward; the 
lingual, directly forward; the facial, forward and upward; the occipital, back- 
ward; and the ascending pharyngeal directly upward on the inner side of the 
internal carotid. The veins met with are: the internal jugular, which lies on the 
outer side of the common and internal carotid arteries, and veins corresponding to 
the above-mentioned branches of the external carotid-viz., the superior thyroid, 
the lingual, facial, ascending pharyngeal, and sometimes the occipital, all of 
which accompany their corresponding arteries and terminate in the internal jugular. 
The nerves in this space are the following: In front of the sheath of the common 
carotid is the descendens hypoglossi. The hypoglossal nerve crosses both the 
internal and external carotids above, curving round the occipital artery at its 
origin. Within the sheath, between the artery and vein, and behind both, is the 
pneumogastric nerve; behind the sheath, the sympathetic. On the outer side of 
the vessels the spinal accessory nerve runs for a short distance before it pierces 
the Sterno-mastoid muscle; and on the inner side of the external carotid, just 
below the hyoid bone, may be seen the internal laryngeal nerve; and, still more 
inferiorly, the external laryngeal nerve. The upper part of the larynx and lower 
part of the pharynx are also found in the front part of this space. 
The Submaxillary Triangle corresponds to the part of the neck immediately 
beneath the body of the jaw. It is bounded, above, by the lower border of the 
body of the jaw and a line drawn from its angle to the mastoid process; below, by 
the posterior belly of the Digastric muscle and the Stylo-hyoid muscle; in front, 
by the anterior belly of the Digastric. It is covered by the integument, superficial 
fascia, Platysma, and deep fascia, ramifying between which are branches of the 
facial and ascending filaments of the superficial cervical nerves. Its floor is formed 
by the Mylo-hyoid and Hyo-glossus muscles. This space contains, in front, the sub- 618 
THE BLOOD-VASCULAR SYSTEM 
maxillary gland, superficial to which is the facial vein, while imbedded in it are the 
facial artery and its glandular branches; beneath this gland, on the surface of the 
Mylo-hyoid muscle, are the submental artery and the mylo-hyoid artery and nerve, 
'rhe posterior part of this triangle is separated from the anterior part by the stylo- 
maxillary ligament: it contains the external carotid artery, ascending deeply in 
the substance of the parotid gland: this vessel here lies in front of, and superficial 
to, the internal carotid, being crossed by the facial nerve, and gives off in its 
course the posterior auricular, temporal, and internal maxillary branches: more 
deeply are the internal carotid artery, the internal jugular vein, and the pneumo- 
gastric nerve, separated from the external carotid by the Stylo-glossus and Stylo- 
pharyngeus muscles and the glosso-pharyngeal nerve.1 
Posterior Triangle of the Neck.-The posterior triangle is bounded, in jront, 
by the Sterno-mastoid muscle; behind, by the anterior margin of the Trapezius; 
its base corresponds to the middle third of the clavicle; its apex, to the occiput. 
The space is crossed, about an inch above the clavicle, by the posterior belly of 
the Omo-hyoid, which divides it unequally into two, an upper or occipital and a 
lower or subclavian triangle. 
The Occipital Triangle, the larger division of the posterior triangle, is bounded, 
in jront, by the Sterno-mastoid; behind, by the Trapezius; below, by the Omo- 
hyoid. Its floor is formed from above downward by the Splenius, Levator anguli 
scapula?, and the Middle and posterior scaleni muscles. It is covered by the 
integument, the Platysma below, the superficial and deep fascise; the spinal 
accessory nerve is directed obliquely across the space from the Sterno-mastoid, 
which it pierces, to the under surface of the Trapezius; below, the descending 
branches of the cervical plexus and the transversalis colli artery and vein cross the 
space. A chain of lymphatic glands is also found running along the posterior 
border of the Sterno-mastoid, from the mastoid process to the root of the neck. 
The Subclavian Triangle, the smaller of the two posterior triangles, is bounded, 
above, by the posterior belly of the Omo-hyoid; below, by the clavicle, its base, 
directed forward, being formed by the Sterno-mastoid. The size of the subclavian 
triangle varies according to the extent of attachment of the clavicular portion of the 
Sterno-mastoid and Trapezius muscles, and also according to the height at which 
the Omo-hyoid crosses the neck above the clavicle. Its height also varies much 
according to the position of the arm, being much diminished by raising the limb, 
on account of the ascent of the clavicle, and increased by drawing the arm down- 
ward, when that bone is depressed. 'Phis space is covered by the integument, 
the Platysma, the superficial and deep fascia1, and crossed by the descending 
branches of the cervical plexus. Just above the level of the clavicle the third 
portion of the subclavian artery curves outward and downward from the outer 
margin of the Scalenus anticus, across the first rib, to the axilla. Sometimes this 
vessel rises as high as an inch and a half above the clavicle, or to any point inter- 
mediate between this and its usual level. Occasionally it passes in front of the 
Scalenus anticus or pierces the fibres of that muscle. The subclavian vein lies 
behind the clavicle, and is usually not seen in this space; but it occasionally rises 
as high up as the artery, and has even been seen to pass with that vessel behind 
the Scalenus anticus. The brachial plexus of nerves lies above the artery, and 
in close contact with it. Passing transversely behind the clavicle are the supra- 
scapular vessels, and traversing its upper angle in the same direction, the trans- 
versalis colli artery and vein. The external jugular vein runs vertically downward 
behind the posterior border of the Sterno-mastoid muscle, to terminate in the 
1 The same remark will apply to this triangle as was made about the inferior carotid triangle. The structures 
enumerated as contained in the back part of the space lie, strictly speaking, beneath the muscles which form 
the posterior boundary of the triangle; but as it is very important to bear in mind their close relation to the 
parotid gland and its boundaries (on account of the frequency of surgical operations on this gland), all these 
parts are spoken of together.-Ed. of 15th English edition. THE INTERNAL CAROTID ARTERY 
619 
subclavian vein; it receives the transverse cervical and suprascapular veins, which 
occasionally form a plexus in front of the artery, and a small vein which crosses 
the clavicle from the cephalic. The small nerve to the Subclavius muscle also 
crosses this triangle about its middle. A lymphatic gland is also found in the space. 
Its floor is formed by the first rib with the first digitation of the Serratus magnus. 
The Internal Carotid Artery (A. Carotis Interna). 
The internal carotid artery supplies the anterior part of the brain, the eye, 
and its appendages, and sends branches to the forehead and nose. Its size 
in the adult is equal to that of the external carotid, though in the child it is 
larger than that vessel. It is remarkable for the number of curvatures that it 
presents in different parts of its course. It occasionally has one or two flexures 
Fig. 399.-The internal carotid and vertebral arteries. Right side. 620 
THE BLOOD-VASCULAR SYSTEM 
near the base of the skull, whilst in its passage through the carotid canal and 
along the side of the body of the sphenoid bone it describes a double curve 
which resembles somewhat the letter S placed horizontally. These curvatures most 
probably diminish the velocity of the current of blood, by increasing the extent of 
surface over which it moves and adding to the impediment produced from friction. 
In considering the course and relations of this vessel it may be conveniently 
divided into four portions: the cervical, petrous, cavernous, and cerebral portions. 
Cervical Portion.-This portion of the internal carotid commences at the 
bifurcation of the common carotid, opposite the upper border of the thyroid 
cartilage, and runs perpendicularly upward, in front of the transverse processes 
of the three upper cervical vertebrae, to the carotid canal in the petrous portion 
of the temporal bone. It is superficial at its commencement, being contained in the 
superior carotid triangle, and lying on the same level as the external carotid, but 
behind that artery overlapped by the Sterno-mastoid and covered by the deep 
fascia, Platysma, and integument: it then passes beneath the parotid gland, being 
crossed by the hypoglossal nerve, the Digastric and Stylo-hyoid muscles, and 
the occipital and posterior auricular arteries. Higher up, it is separated from the 
external carotid by the Stylo-glossus and Stylo-pharyngeus muscles, the glosso- 
pharyngeal nerve, and pharyngeal branch of the pneumogastric. 
Relations.-It is in relation, behind, with the Rectus capitis anticus major, the 
superior cervical ganglion of the sympathetic, and superior laryngeal nerve; exter- 
nally, with the internal jugular vein and pneumogastric nerve, the nerve lying 
on a plane posterior to the artery; internally, with the pharynx, tonsil, the superior 
laryngeal nerve, and ascending pharyngeal artery. At the base of the skull the 
glosso-pharyngeal, vagus, spinal accessory, and hypoglossal nerves lie between 
the artery and the internal jugular vein. 
Plan of the Relations of the Internal Carotid Artery in the Neck. 
In front. 
Skin, superficial and deep fasciae. 
Platysma. 
Sterno-mastoid. 
Occipital and posterior auricular arteries. 
Hypoglossal nerve. 
Parotid gland. 
Stylo-glossus and Stylo-pharyngeus muscles, 
Glosso-pharyngeal nerve. 
Pharyngeal branch of the pneumogastric. 
Externally. 
Internal jugular vein. 
Pneumogastric nerve. 
Internally. 
Pharynx. 
Superior laryngeal nerve. 
Ascending pharyngeal artery. 
Tonsil. 
Internal 
Carotid 
Artery.. 
Behind. 
Rectus capitis anticus major, 
Sympathetic. 
Superior laryngeal nerve. 
Petrous Portion.-When the internal carotid artery enters the canal in the 
petrous portion of the temporal bone, it first ascends a short distance, then curves 
forward and inward, and again ascends as it leaves the canal to enter the cavity of 
the skull between the lingula and petrosal process. In this canal the artery lies 
at first in front of the cochlea and tympanum; from the latter cavity it is separated 
by a thin, bony lamella, which is cribriform in the young subject, and is often 
absorbed in old age. Farther forward it is separated from the Gasserian ganglion 
by a thin plate of bone, which forms the floor of the fossa for the ganglion and the 
roof of the horizontal portion of the canal. Frequently this bony plate is more THE INTERNAL CAROTID ARTERY 
621 
or less deficient, and then the ganglion is separated from the artery by a fibrous 
membrane. The artery is separated from the bony wall of the carotid canal by a 
prolongation of dura mater, and is surrounded by a number of small veins and 
by filaments of the carotid plexus, derived from the ascending branch of the 
superior cervical ganglion of the sympathetic. 
Cavernous Portion.-The internal carotid artery in this part of its course is 
situated between the layers of the dura mater forming the cavernous sinus, but is 
covered by the lining membrane of the sinus. It at first ascends to the posterior 
clinoid process, then passes forward by the side of the body of the sphenoid bone, 
and again curves upward on the inner side of the anterior clinoid process, and 
perforates the dura mater, forming the roof of the sinus. In this part of its course 
it is surrounded by filaments of the sympathetic nerve, and has in relation with it 
externally the sixth nerve. 
Cerebral Portion.-Having perforated the dura mater, on the inner side of the 
anterior clinoid process, the internal carotid passes between the second and third 
cranial nerves to the anterior perforated spot at the inner extremity of the fissure 
of Sylvius, where it gives off its terminal or cerebral branches. This portion 
of the artery has the optic nerve on its inner side, and the third nerve externally. 
Peculiarities.-The length of the internal carotid varies according to the length of the neck, 
and also according to the point of bifurcation of the common carotid. Its origin sometimes 
takes place from the arch of the aorta; in such rare instances this vessel has been found to be 
placed nearer the middle line of the neck than the external carotid, as far upward as the larynx, 
when the latter vessel crossed the internal carotid. The course of the vessel, instead of being 
straight, may be very tortuous. A few instances are recorded in which this vessel was altogether 
absent: in one of these the common carotid passed up the neck, and gave off the usual branches 
of the external carotid, the cranial portion of the internal carotid being replaced by two branches 
of the internal maxillary, which entered the skull through the foramen rotundum and the foramen 
ovale and joined to form a single vessel. 
Surgical Anatomy.-The cervical part of the internal carotid is very rarely wounded. Mr. 
Cripps, in an interesting paper in the Medico-Chirurgical Transactions, compares the rareness 
of a wound of the internal carotid with one of the external carotid or its branches. It is, however, 
sometimes injured by a stab or gunshot wound in the neck, or even occasionally by. a stab from 
within the mouth, as when a person receives a thrust from the end of a parasol or falls down 
with a tobacco-pipe in his mouth. It used to be believed that the internal carotid was occa- 
sionally wounded in the removal of the tonsil. Such an accident cannot happen if the artery is 
normally placed. The severe and sometimes fatal hemorrhage which has followed this opera- 
tion in a few instances probably had as its source enlarged branches of the ascending pharyn- 
geal, tonsillar, or ascending palatine arteries. Recently, however, Dr. Gwilym G. Davis, of 
Philadelphia, demonstrated a specimen in which the internal carotid could have been wounded 
by incision of the tonsil. The indications for ligature are wounds, when the vessel should be 
exposed by a careful dissection and tied above and below the bleeding point; and aneurism, 
which if non-traumatic may be treated by ligature of the common carotid, but if traumatic in 
origin by exposing the sac and tying the vessel above and below. The incision for ligature of 
the cervical portion of the internal carotid should be made along the anterior border of the 
Sterno-mastoid, from the angle of the jaw to the upper border of the thyroid cartilage. The 
superficial structures being divided and the Sterno-mastoid defined and drawn outward, the 
cellular tissue must be carefully separated and the posterior belly of the Digastric muscle and 
the hypoglossal nerve sought for as guides to the vessel. When the artery is found the external 
carotid should be drawn inward and the Digastric muscles upward, and the aneurism needle 
passed from without inward. 
Branches.-The branches given off from the internal carotid artery are- 
From the Petrous portion 
Tympanic (internal or deep). 
From the Cavernous portion 
Arteriae Receptaculi. 
Anterior Meningeal. 
Ophthalmic. 
Anterior Cerebral. 
Middle Cerebral. 
Posterior Communicating. 
Anterior Choroid. 
From the Cerebral portion 622 
THE BLOOD-VASCULAll SYSTEM 
The cervical portion of the internal carotid gives off no branches. 
The Tympanic (ramus caroticotympanicus) is a small branch from the petrous 
portion, which enters the cavity of the tympanum through a minute foramen in 
the carotid canal, and anastomoses with the tympanic branch of the internal 
maxillary, and with the stylo-mastoid artery. 
The Arteriae Receptaculi are numerous small vessels, derived from the inter- 
nal carotid in the cavernous sinus; they supply the pituitary body, the Gasserian 
ganglion, and the walls of the cavernous and inferior petrosal sinuses. Some of 
these branches anastomose with branches of the middle meningeal. 
The Anterior Meningeal (a. meningea anterior) is a small branch which 
passes over the lesser wing of the sphenoid to supply the dura mater of the ante- 
rior fossa; it anastomoses with the meningeal branch from the posterior ethmoidal 
artery. 
The Ophthalmic Artery (a. ophthalmica) arises from the internal carotid, 
just as that vessel is emerging from the cavernous sinus, on the inner side of the 
anterior clinoid process, and enters the orbit through the optic foramen, below and 
Nasal. 
Frontal. 
Palpebral. 
Supra-orbital. 
Anterior ethmoidal.- 
Posterior ethmoidal.- 
Temporal branches 
of lachrymal. 
Arteria 
centralis retinae. 
Lachrymal. 
Muscular. 
•Ophthalmic. 
Internal carotid. 
Fig. 400.-The ophthalmic artery and its branches, the roof of the orbit having been removed. 
on the outer side of the optic nerve. It then passes over the nerve to the inner wall 
of the orbit, and thence horizontally forward, beneath the lower border of the 
Superior oblique muscle, to a point behind the internal angular process of the 
frontal bone, where it divides into two terminal branches, the frontal and nasal 
branches. As the artery crosses the optic nerve it is accompanied by the nasal 
nerve, and is separated from the frontal nerve by the Rectus superior and 
Levator palpebrae superioris muscles. 
Branches.-The branches of this vessel may be divided into an orbital group, 
which are distributed to the orbit and surrounding parts, and an ocular group, 
which supply the muscles and globe of the eye: THE INTERNAL CAROTID ARTERY 
623 
Orbital ^Group. 
Lachrymal. 
Supraorbital. 
Posterior Ethmoidal. 
Anterior Ethmoidal. 
Internal Palpebral. 
Frontal. 
Nasal. 
Ocular Group. 
Short Ciliary. 
Long Ciliary. 
Anterior Ciliary. 
Arteria Centralis Retinae. 
Muscular. 
The Lachrymal (a. lachrimalis) is one of the largest branches derived from the 
ophthalmic, arising close to the optic foramen; not infrequently it is given off from 
the ophthalmic artery before it enters the orbit. It accompanies the lachrymal nerve 
along the upper border of the External rectus muscle, and is distributed to the 
lachrymal gland. Its terminal branches, escaping from the gland, are distributed to 
the eyelids and conjunctiva: of those supplying the eyelids, two are of considerable 
size and are named the external palpebral; they run inward in the upper and lower 
lids respectively, and anastomose with the internal palpebral arteries, forming an 
arterial circle in this situation. The lachrymal artery gives off one or two malar 
branches, one of which passes through a foramen in the malar bone, to reach the 
temporal fossa, and anastomoses with the deep temporal arteries; the other appears 
on the cheek through the malar foramen, and anastomoses with the transverse facial. 
A branch, the recurrent, is also sent backward through the sphenoidal fissure to the 
dura mater, which anastomoses with a branch of the middle meningeal artery. 
Peculiarities.-The lachrymal artery is sometimes derived from one of the anterior branches 
of the middle meningeal artery. 
The Supraorbital Artery (a. supraorb italis) arises from the ophthalmic as that 
vessel is crossing over the optic nerve. Ascending so as to arise above all the muscles 
of the orbit, it passes forward, with the supraorbital nerve, between the periosteum 
and Levator palpebrse muscle; and, passing through the supraorbital foramen, 
divides into a superficial and deep branch, which supply the integument, the 
muscles, and the pericranium of the forehead, anastomosing with the frontal, the 
anterior branch of the temporal, and the supraorbital artery of the opposite side. 
This artery in the orbit supplies the Superior rectus and the Levator palpebne 
muscles, and sends a branch inward, across the pulley of the Superior oblique 
muscle, to supply the parts at the inner canthus. At the supraorbital foramen 
it frequently transmits a branch to the diploe. 
'The Ethmoidal Branches are two in number-posterior (a. ethmoidalis posterior) 
and anterior (a. ethmoidalis anterior). The former, which is the smaller, passes 
through the posterior ethmoidal foramen, supplies the posterior ethmoidal cells, 
and, entering the cranium, gives off a meningeal branch, which supplies the adja- 
cent dura mater, and nasal branches which descend into the nose through aper- 
tures in the cribriform plate, anastomosing with branches of the spheno-palatine. 
The anterior ethmoidal artery accompanies the nasal nerve through the anterior 
ethmoidal foramen, supplies the anterior ethmoidal cells and frontal sinuses, and, 
entering the cranium, gives off a meningeal branch, which supplies the adjacent 
dura mater and nasal branches, which descend into the nose, through the slit by 
the side of the crista galli, and, running along the groove on the under surface of 
the nasal bone, supply the skin of the nose. 
The Internal Palpebral Arteries (aa. palpebrales mediates), two in number, supe- 
rior and inferior, arise from the ophthalmic, opposite the pulley of the Superior 
oblique muscle; they leave the orbit to encircle the eyelids near their free margin, 
forming a superior tarsal arch (arcus tarseus superior) anti an inferior tarsal arch (arcus 
tarseus inferior), which lie between the Orbicularis muscle and the tarsal plates; 624 
THE BLOOD-VASCUL AH SYSTEM 
the superior palpebral inosculating at the outer angle of the orbit with the orbital 
branch of the temporal artery, and with the upper of the two external palpebral 
branches from the lachrymal artery-the inferior palpebral inosculating, at the 
outer angle of the orbit, with the lower of the two external palpebral branches 
Longitudinal 
Fissure. 
Fig. 401.- The arteries of the base of the brain. The right half of the cerebellum and pons have been removed. 
N. B.-It will be noticed that the two anterior cerebral arteries have been drawn at a considerable distance from 
each other: this makes the anterior communicating artery appear very much longer than it really is. 
from the lachrymal and with the transverse facial artery, and at the inner side 
of the lid with a branch from the angular artery. From this last anastomosis a 
branch passes to the nasal duct, ramifying in its mucous membrane, as far as the 
inferior meatus. THE INTERNAL CAROTID ARTERY 
625 
The Frontal Artery (a. frontalis), one of the terminal branches of the ophthal- 
mic, passes from the orbit at its inner angle, and, ascending on the forehead, sup- 
plies the integument, muscles, and pericranium, anastomosing with the supra- 
orbital artery and with the frontal artery of the opposite side. 
The Nasal Artery (a. dorsalis nasi), the other terminal branch of the ophthalmic, 
emerges from the orbit above the tendo oculi, and, after giving a branch to the 
upper part of the lachrymal sac, divides into two branches, one of which crosses 
the root of the nose, the transverse nasal, and anastomoses with the angular artery; 
the other, the dorsalis nasi, runs along the dorsum of the nose, supplies its outer 
surface, and anastomoses with the artery of the opposite side and with the lateral 
nasal branch of the facial. 
Lower 
Frontal 
Fissure of 
Rolando 
Fig. 402.-Vascular area of the upper surface of the cerebrum. I. The part supplied by the external and 
inferior frontal artery. II. The part supplied by the ascending frontal. III. The part supplied by the ascending 
parietal. IV. The part supplied by the parieto-sphenoidal artery. (After Duret.) 
The Ciliary Arteries (a. ciliares) are divisible into three groups, the short, long, 
and anterior. The short ciliary arteries (aa. ciliaris posteriores breves'), from six 
to twelve in number, arise from the ophthalmic or some of its branches; they sur- 
round the optic nerve as they pass forward to the posterior part of the eyeball, 
pierce the sclerotic coat around the entrance of the nerve, and supply the choroid 
coat and ciliary processes. The long ciliary arteries (aa. ciliares posteriores longat), 
two in number, pierce the posterior part of the sclerotic at some little distance from 
the optic nerve, and run forward, along each side of the eyeball, between the 
sclerotic and choroid, to the ciliary muscle, where they divide into two branches; 
these form an arterial circle, the circulus major, around the circumference of the 
iris, from which numerous radiating branches pass forward, in its substance, to 
its free margin, where they form a second arterial circle, the circulus minor, around 
its pupillary margin. The anterior ciliary arteries (aa. ciliares anteriores) are 626 
THE BLOOD-VASCULAR SYSTEM 
derived from the muscular branches; they pass to the front of the eyeball in com- 
pany with the tendons of the Recti muscles, form a vascular zone beneath the 
conjunctiva, and then pierces the sclerotic a short distance from the cornea and 
terminate in the circulus major of the iris. 
The Arteria Centralis Retinae is the first and one of. the smallest branches of the 
ophthalmic artery. It runs for a short distance within the dural sheath of the 
optic nerve, but about half an inch behind the eyeball it pierces the optic nerve 
obliquely, and runs forward in the centre of its substance, and enters the globe 
of the eye through the porus opticus. Its mode of distribution will be described 
in the account of the anatomy of the eye. 
The Muscular Branches (rami musculares), two in number, superior and inferior, 
frequently spring from a common trunk. The superior, the smaller, often wanting, 
supplies the Levator palpebne, Superior rectus, and Superior oblique. The infe- 
rior, more constant in its existence, passes forward, between the optic nerve and 
the Inferior rectus muscle, and is distributed to the External, Internal, and 
Inferior recti, and Inferior oblique. This vessel gives off most of the anterior 
ciliary arteries. Additional muscular branches are given off from the lachrymal 
and supraorbital arteries or from the ophthalmic itself. 
Fissure of Rolando 
Parieto- 
occipital 
fFissure 
Fig. 403.-Vascular area of the internal surface of the cerebrum. I. The part supplied by the anterior 
internal frontal. II. The part supplied by the middle internal frontal. III. The part supplied by the posterior 
internal frontal. IV. The part supplied by the posterior temporal. V The part supplied by the occipital, both 
terminal branches of the posterior cerebral. (After Duret.) 
The Anterior Cerebral (a. cerebri anterior) arises from the internal carotid 
at the inner extremity of the fissure of Sylvius. It passes forward and inward across 
the anterior perforated space, above the optic nerve, to the commencement of the 
great longitudinal fissure. Here it comes into close relationship with the anterior 
cerebral artery of the opposite side, and the two vessels are connected together by 
a short anastomosing trunk, about two lines in length, the anterior communicating 
artery. From this point the two vessels run side by side in the longitudinal fissure, 
curve round the genu of the corpus callosum, and, turning backward, continue 
along its upper surface to its posterior part, where they terminate by anastomosing 
with the posterior cerebral arteries. 
Branches.-In their course the anterior cerebral arteries give off the following 
branches: 
Antero-median ganglionic 
Inferior internal frontal. 
Anterior internal frontal. 
Middle internal frontal. 
Posterior internal frontal. THE INTERNAL CAROTID ARTERY 
627 
The Antero-median Ganglionic is a group of small arteries which arise at the 
commencement of the anterior cerebral artery; they pierce the anterior perforated 
space and lamina cinerea, and supply the head of the caudate nucleus. 
The Inferior Internal Frontal Branches or the Internal Orbital Arteries, two or 
three in number, are distributed to the orbital surface of the frontal lobe, where 
they supply the olfactory lobe, gyrus rectus, and internal orbital convolution. 
The Anterior Internal Frontal supplies a part of the marginal convolution, and 
sends branches over the edge of the hemisphere to the superior and middle frontal 
convolutions and upper part of the ascending frontal convolution. 
The Middle Internal Frontal supplies the corpus callosum, the convolution of the 
corpus callosum, the inner surface of the first frontal convolution, and the upper 
part of the ascending frontal convolution. 
Fig. 404.-Vascular area of the inferior surface of the cerebrum. I. The part supplied by the anterior tem- 
poral from the posterior cerebral artery. II. The part supplied by the posterior temporal from the posterior 
cerebral artery. III. The part supplied by the occipital from the posterior cerebral artery. (After Duret.) 
The Posterior Internal Frontal supplies the lobus quadratus and adjacent outer 
surface of the hemisphere. 
The Anterior Communicating Artery (a. communicans anterior) is a short branch, 
about two lines in length, but of moderate diameter, connecting together the two 
anterior cerebral arteries across the longitudinal fissure. Sometimes this vessel is 
wanting, the two arteries joining together to form a single trunk, which afterward 
divides. Or the vessel may be wholly or partially divided into two; frequently it 
is longer and smaller than usual. It gives off some of the antero-median gan- 
glionic group of vessels, which are, however, principally derived from the anterior 
cerebral. 
The Middle Cerebral Artery (a. cerebri media) (Fig. 405), the largest branch 
of the internal carotid, passes obliquely outward along the fissure of Sylvius, and 
opposite the island of Reil divides into its terminal branches. 628 
THE BLOOD-VASCULAR SYSTEM 
Branches.-The branches of the middle cerebral artery are- 
Antero-lateral ganglionic. 
Inferior external frontal. 
Ascending frontal. 
Ascending parietal. 
Parieto-temporal. 
The Antero-lateral Ganglionic Branches are a group of small arteries which arise 
at the commencement of the middle cerebral artery; they pierce the anterior 
perforated space and supply the greater part of the caudate nucleus, the lenticular 
nucleus, the internal capsule, and a part of the optic thalamus. One artery of this 
group (one of the lenticulo-striate arteries) is of larger size than the rest, and is of 
special importance, as being the artery in the brain most frecjuently ruptured; it 
has been termed by Charcot the artery of cerebral hemorrhage. It passes up between 
the lenticular nucleus and the external capsule, and ultimately ends in the caudate 
nucleus. 
FISSURE OF 
ROLANDO. 
Antero-lateral 
Ganglionic or Per- 
forating Branches. 
Middle Cerebral 
Artery. 
Fig. 405.-The distribution of the middle cerebral artery. (After Charcot.) 
The Inferior External Frontal supplies the third or inferior frontal convolution, 
Broca's convolution, and the outer part of the orbital surface of the frontal lobe. 
The Ascending Frontal supplies the ascending frontal convolution. 
The Ascending Parietal supplies the ascending parietal convolution and the 
lower part of the superior parietal convolution. 
The Parieto-temporal or Parieto-sphenoidal supplies the supramarginal, the 
superior, and part of the middle temporal convolutions, and the angular gyrus. 
It sends branches to the temporal lobe. 
The Posterior Communicating Artery (a. communicans posterior) arises 
from the back part of the internal carotid, runs directly backward, and anasto- 
moses with the posterior cerebral, a branch of the basilar. This artery varies 
considerably in size, being sometimes small, and occasionally so large that the 
posterior cerebral may be considered as arising from the internal carotid rather 
than from the basilar. It is frequently larger on one side than on the other side. 
From the posterior half of this vessel are given off a number of small branches, 
the postero-median ganglionic branches, which, with similar vessels from the pos- 
terior cerebral, pierce the posterior perforated space and supply the internal sur- 
faces of the optic thalami and the walls of the third ventricle. 
Phe Anterior Choroid (a. chorioidea) is a small but constant branch which 
arises from the back part of the internal carotid, near the posterior communicating 
artery. Passing backward and outward between the temporal lobe and the crus THE BLOOD-VESSELS OF THE BRAIN 
629 
cerebri, it enters the descending horn of the lateral ventricle through the trans- 
verse fissure and ends in the choroid plexus. It is distributed to the hippocampus 
major, corpus fimbriatum, velum interpositum, and choroid plexus. 
THE BLOOD-VESSELS OF THE BRAIN. 
Recent investigations have tended to show that the mode of distribution of 
the vessels of the brain has an important bearing upon a considerable number of 
the anatomical lesions of which this part of the nervous system may be the seat; 
it therefore becomes important to consider a little more in detail the way in which 
the cerebral vessels are distributed. 
The cerebral arteries are derived from the internal carotid and the vertebral, 
which at the base of the brain form a remarkable anastomosis known as the circle 
■Anterior cerebral artery. 
Mniernal'earotid artery. 
Middle cerebral artery. 
/Posterior cei'ebral artery. 
Vertebral artery. 
Fig. 406.-Diagram of the arterial circulation at the base of the brain. I. Antero-median group of ganglionic 
branches. II. Postero-median group. III. Right and left antero-lateral group. IV. Right and left postero- 
lateral group. The dotted line shows the limit of the ganglionic circle. (After Charcot.) 
of Willis (circulus arteriosus [IFiZZm]). The tortuosity of the constituent vessels 
of the anastomosis lessens the impact of the circulation and saves the brain from 
damage. The outline of the vessels forming the so-called circle is said by Sappey 
to be hexagonal, and by Testut to be heptagonal. The circle of Willis is formed 
in front by the anterior cerebral arteries, branches of the internal carotid, which 
are connected together by the anterior communicating; behind by the two posterior 
cerebrals, branches of the basilar which are connected on each side to the internal 
carotid by the posterior communicating (Fig. 401). The parts of the brain 
included within this arterial circle are the lamina cinerea, the commissure of the 
optic nerves, the infundibulum, the tuber cinereum, the corpora albicantia, and 
the posterior perforated space. This arrangement of the vessels of the circle of 
Willis is not invariable; according to Windle it is maintained in little more than 
half the recorded cases. In the other cases there are various anomalies. 630 
THE BLOOD-VASCULAR SYSTEM 
From the circle of Willis arise the three trunks which together supply each 
cerebral hemisphere. From its anterior part proceed the two anterior cerebrals, 
from its antero-lateral part the middle cerebrals, and from its posterior part the 
posterior cerebrals. Each of these principal arteries gives origin to two very 
different systems of secondary vessels. One of these systems has been named the 
central ganglionic system, and the vessels belonging to it supply the central ganglia 
of the brain; the other has been named the cortical arterial system, and its vessels 
ramify in the pia mater and supply the cortex and subjacent medullary matter. 
These two systems, though they have a common origin, do not communicate at any 
point of their peripheral distribution, and are entirely independent of each other. 
Though some of the arteries of the cortical system approach, at their terminations, 
the regions supplied by the central ganglionic system, no communication between 
the two sets of vessels takes place, and there is between the parts supplied by the 
two systems a borderland of diminished nutritive activity, where, it is said, 
softening is especially liable to occur in the brains of old people. 
The Central Ganglionic System.-All the vessels belonging to this system 
are given off from the circle of Willis or from the vessels immediately after their 
origin from it, so that if a circle is drawn at a distance of about an inch from the 
circle of Willis, it will include the origin of all the arteries belonging to this system 
(Fig. 406). 'Fhe vessels of this system form six principal groups: (I.) the antero- 
median group, derived from the anterior cerebrals and anterior communicating; 
(II.) the postero-median group, from the posterior cerebrals and posterior communi- 
cating; (III.) the right and left antero-lateral group, from the middle cerebrals; and 
(IV.) the right and left postero-lateral group, from the posterior cerebrals, after they 
have wound round the crura cerebri. The vessels belonging to this system are 
Fig. 407.-Distribution of the cortical arteries. 1. Medullary arteries. 1'. Group of medullary arteries in 
the sulcus between two adjacent convolutions. 1". Arteries situated among the short association fibres. 2,2. 
Cortical arteries, a. Capillary network with fairly wide meshes, situated beneath the pia mater, b. Net- 
work with more compact, polygonal meshes, situated in the cortex, c. Transitional network with wider 
meshes, d. Capillary network in the white matter. (After Charcot.) 
larger than those of the cortical system, and are what Cohnheim has termed 
terminal arteries; that is to say, vessels which from their origin to their termination 
neither supply nor receive any anastomotic branches, so that by one of the small THE SUBCLAVIAN ARTERY 
631 
vessels only a limited area of the central ganglia can be injected; and the injection 
cannot be driven beyond the area of the part supplied by the particular vessel which 
is the subject of the experiment. 
The Cortical Arterial System.-The vessels forming this system are the ter- 
minal branches of the anterior, middle, and posterior cerebral arteries, described 
above. These vessels divide and ramify in the substance of the pia mater, and give 
off nutrient arteries which penetrate the cortex perpendicularly. 'These nutrient 
vessels are divisible into two classes-the long and short. The long-or, as they 
are sometimes called, the medullary-arteries pass through the gray matter to pene- 
trate the centrum ovale to the depth of about an inch and a half, without intercom- 
municating otherwise than by very fine capillaries, and thus constitute so many 
independent small systems. The short vessels are confined to the cortex, where 
they form with the long vessels a compact network in the middle zone of the gray 
matter, the outer and inner zones being sparingly supplied with blood (Fig. 407). 
The vessels of the cortical arterial system are not so strictly terminal as those of the 
central ganglionic system, but they approach this type very closely, so that injec- 
tion of one area from the vessel of another area, though it may be possible, is fre- 
quently very difficult, and is only effected through vessels of small calibre. As a 
result of this, obstruction of one of the main branches or its divisions may have 
the effect of producing softening in a very limited area of the cortex.1 
ARTERIES OF THE UPPER EXTREMITY. 
The artery which supplies the upper extremity continues as a single trunk 
from its commencement down to the elbow, but different portions of it have 
received different names according to the region through which it passes. That 
part of the vessel which extends from its origin to the outer border of the first 
rib is termed the subclavian artery; beyond this point to the lower border of the 
axilla it is termed the axillary artery; and from the lower margin of the axillary space 
to the bend of the elbow it is termed the brachial artery; here the single trunk 
terminates by dividing into two branches, the radial and ulnar-an arrangement 
precisely similar to what occurs in the lower limb. 
THE SUBCLAVIAN ARTERY (A. SUBCLAVIA) (Fig. 408). 
The subclavian artery on the right side arises from the innominate artery 
opposite the right sterno-clavicular articulation; on the left side it arises from 
the arch of the aorta. It follows, therefore, that these two vessels must, in the first 
part of their course, differ in their length, their direction, and their relation with 
neighboring parts. 
In order to facilitate the description of these vessels, more especially from a 
surgical point of view, each subclavian artery has been divided into three parts. 
The first portion, on the right side, passes upward and outward from the origin 
of the vessel to the inner border of the Scalenus anticus. On the left side it ascends 
nearly vertically, to gain the inner border of that muscle. The second part passes 
outward, behind the Scalenus anticus; and the third part passes from the outer 
margin of that muscle, beneath the clavicle, to the outer border of the first rib, 
where it becomes the axillary artery. The first portion of these two vessels differs 
so much in its course and in its relations with neighboring parts that it will be 
described separately. The second and third parts are alike on the two sides. 
1 The student who desires further information on this subject is referred to Charcot's Localization of Cerebral 
and Spinal Diseases, p. 42 el seq., whence the facts above given have been principally derived.-En. of 15th 
English edition. 632 
THE BLOOD-VASCULAR SYSTEM 
First Part of the Right Subclavian Artery (Figs. 389, 390, 392, 408). 
On the right side the subclavian artery arises from the arteria innominata, oppo- 
site the upper part of the right sterno-clavicular articulation, and passes upward 
and outward to the inner margin of the Scalenus anticus muscle (Figs. 389, 390, 
and 408). In this part of its course it ascends a little above the clavicle, the extent 
to which it does so varying in different cases. 
Phrenic nerve. 
Vertebral artery. 
Inferior thyroid artery. 
Supra-scapular 
artery. 
.Pneumo- 
gastric 
nerve. 
Supra- 
scapular 
nerve. 
Subclavian 
artery. 
External jugu- 
lar vein. 
Right innomi- 
nate vein. 
Innomi- 
nate artery. 
Musculo- 
cutaneous 
nerve. 
■Subscapular 
artery. 
Profunda artery. 
Musculo-spiral nerve. 
Fig. 408.-The subclavian artery, showing its relations. (From a preparation in the Museum of the Royal 
College of Surgeons of England.) 
Relations.-It is covered,in front,by the integument, superficial fascia, Platysma, 
deep fascia, the clavicular origin of the Sterno-mastoid, the Sterno-hyoid, and 
Sterno-thyroid muscles, and a second layer of deep fascia. It is crossed by the 
internal jugular and vertebral veins, and by the pneumogastric nerve and the 
cardiac branches of the sympathetic nerve. A loop of the sympathetic nerve 
itself also crosses the artery, forming a ring around the vessels. The anterior 
jugular vein passes outward in front of the artery but is not in contact with it, 
being separated from it by the Sterno-hyoid and Sterno-thyroid muscles. Below 
and behind the artery is the pleura, which separates it from the apex of the lung; 
behind is the cord of the sympathetic nerve; the recurrent laryngeal nerve winds 
round the lower and back part of the vessel. THE SUBCLAVIAN ARTERY 
633 
Plan of the Relations of First Portion of the Right Subclavian Artery. 
In front. 
Skin, superficial fascia. 
Platysma, deep fascia. 
Clavicular origin of Sterno-mastoid. 
Sterno-hyoid and Sterno-thyroid. 
Anterior jugular, Internal jugular, and vertebral veins. 
Pneumogastric and cardiac nerves. 
Loop from the sympathetic. 
Right 
Subclavian 
Artery. 
First Portion. 
Beneath. 
Pleura. 
Recurrent laryngeal nerve. 
Behind. 
Recurrent laryngeal nerve. 
Sympathetic. 
Pleura and apex of lung. 
First Part of the Left Subclavian Artery (Figs. 388, 389). 
The left subclavian artery arises from the end of the arch of the aorta, opposite 
the fourth dorsal vertebra, and ascends nearly vertically to the inner margin of 
the Scalenus anticus muscle. This part of the vessel is, therefore, longer than the 
right, is situated deeply in the cavity of the chest, and is directed nearly vertically 
upward, instead of arching outward like the vessel of the opposite side. 
Relations.-It is in relation, in front, with the pneumogastric, cardiac,and phrenic 
nerves, which lie parallel with it, the left carotid artery, left internal jugular 
and vertebral veins, and the commencement of the left innominate vein and is 
covered by the Sterno-thyroid, Sterno-hyoid, and Sterno-mastoid muscles; behind, 
it is in relation with the oesophagus, thoracic duct, inferior cervical ganglion of the 
sympathetic, and Longus colli muscle; higher up, however, the oesophagus and 
thoracic duct lie to its right side; the latter ultimately arching over the vessel to 
join the angle of union between the subclavian and internal jugular veins. To 
its inner side are the oesophagus, trachea, and thoracic duct; to its outer side, the 
left pleura and lung. 
Plan of the Relations of First Portion of the Left Subclavian Artery. 
In front. 
Pneumogastric, cardiac, and phrenic nerves. 
Left carotid artery. 
Thoracic duct. 
Left internal jugular, vertebral, and innominate veins. 
Sterno-thyroid, Sterno-hyoid, and Sterno-mastoid muscles. 
Inner side. 
Trachea. 
(Esophagus. 
Thoracic duct. 
Left 
Subclavian 
Artery. 
Outer side. 
Pleura and left lung. 
Behind. 
(Esophagus and thoracic duct. 
Inferior cervical ganglion of sympathetic. 
Longus colli. 
Second and Third Parts of the Subclavian Artery (Figs. 392, 408). 
The Second Portion of the Subclavian Artery lies behind the Scalenus anticus 
muscle; it is very short, and forms the highest part of the arch described by that 
vessel. THE BLOOD-VASCULAR SYSTEM 
634 
Relations.-It is covered, in front, by the skin, superficial fascia, Platysma, 
deep cervical fascia, the Sterno-mastoid and the Scalenus anticus muscles. On 
the right side the phrenic nerve is separated from the second part of the artery by 
the Scalenus anticus muscle, while on the left side the nerve crosses the first part 
of the artery immediately to the inner edge of the muscle. Behind, it is in rela- 
tion with the pleura and the Scalenus medius muscle. Above, with the brachial 
plexus of nerves. Below, with the pleura. The subclavian vein lies below and 
in front of the artery, separated from it by the Scalenus anticus muscle. 
Plan of the Relations of Second Portion of Subclavian Artery. 
In front. 
Skin and superficial fascia. 
Platysma and deep cervical fascia. 
Stern o-mastoid. 
Phrenic nerve. 
Scalenus anticus. 
Subclavian vein. 
Above. 
Brachial plexus. 
Subclavian 
Artery. 
Second 
portion. 
Below. 
Pleura. 
Behind. 
Pleura and Middle Scalenus. 
The Third Portion of the Subclavian Artery passes downward and outward 
from the outer margin of the Scalenus anticus muscle to the outer border of the 
first rib, where it becomes the axillary artery. This portion of the vessel is the 
most superficial, and is contained in the subclavian triangle (see page 618). 
Relations.-It is covered, in front, by the skin, the superficial fascia, the Platysma 
the descending clavicular branches of the cervical plexus, and the deep cervical 
fascia; by the clavicle, the Subclavius muscle, the suprascapular artery and 
vein, and the transverse cervical vein; the nerve to the Subclavius muscle passes 
vertically downward in front of the artery. The external jugular vein crosses 
the artery at its inner side, and receives the suprascapular and transverse cervical 
veins, which frequently form a plexus in front of it. The subclavian vein is 
below and in front of the artery, lying close behind the clavicle. Behind, it lies on 
the Middle scalenus muscle and the lowest cord of the brachial plexus, formed 
by the union of the last cervical and first dorsal nerves. Above it, and to its 
outer side, is the brachial plexus and Omo-hyoid muscle. Below, it rests on the 
upper surface of the first rib. 
Plan of the Relations of Third Portion of Subclavian Artery. 
In front. 
Skin and superficial fascia. 
Platysma and deep cervical fascia. 
Descending branches of cervical plexus. Nerve to Subclavius muscle. 
Subclavius muscle, suprascapular artery, and vein. 
The external jugular and transverse cervical veins. 
The clavicle. 
Above. 
Brachial plexus. 
Omo-hyoid. 
Subclavian 
Artery. 
Third 
portion. 
Below. 
First rib. 
Behind. 
Scalenus medius. 
Lower cord of brachial plexus. THE SUBCLAVIAN ARTERY 
635 
Peculiarities.-The subclavian arteries vary in their origin, their course, and the height to 
which they rise in the neck. 
The origin of the right subclavian from the innominate takes place, in some cases, above the 
sterno-clavicular articulation, and occasionally, but less frequently, in the cavity of the thorax, 
below that point. Or the artery may arise as a separate trunk from the arch of the aorta. In 
such cases it may be either the first, second, third, or even the last branch derived from that 
vessel; in the majority of cases it is the first or last, rarely the second or third. When it is the first 
branch, it occupies the ordinary position of the innominate artery; when the second or third, it 
gains its usual position by passing behind the right carotid; and when the last branch, it arises 
from the left extremity of the arch, at its upper or back part, and passes obliquely toward the 
right side, usually behind the trachea, oesophagus, and right carotid, sometimes between the 
oesophagus and trachea to the upper border of the first rib, whence it follows its ordinary course. 
In very rare instances this vessel arises from the thoracic aorta, as low down as the fourth 
dorsal vertebra. Occasionally it perforates the Scalenus anticus muscle; more rarely it passes 
in front of that muscle. Sometimes the subclavian vein passes with the artery behind the 
Scalenus anticus muscle. The artery may ascend as high as an inch and a half above the 
clavicle or any intermediate point between this and the upper border of the bone, the right 
subclavian usually ascending higher than the left. 
The left subclavian is occasionally joined at its origin with the left carotid. 
Surface Marking.-The course of the subclavian artery in the neck may be mapped out 
by describing a curve, with its convexity upward at the base of the posterior triangle. The inner 
end of this curve corresponds to the sterno-clavicular joint, the outer end of the centre of the 
lower border of the clavicle. The curve is to be drawn with such an amount of convexity that 
its mid-point reaches half an inch above the upper border of the clavicle. The left subclavian 
artery is more deeply placed than the right in the first part of its course, and, as a rule, does not 
reach quite as high a level in the neck. It should be borne in mind that the posterior border of 
the Sterno-mastoid muscle corresponds to the outer border of the Scalenus anticus muscle, so 
that the third portion of the artery, that part most accessible for operation, lies immediately 
external to the posterior border of the Sterno-mastoid muscle. 
Surgical Anatomy.-The relations of the subclavian arteries of the two sides having been 
examined, the student should direct his attention to a consideration of the best position in which 
compression of the vessel may be effected, or in what situation a ligature may fie best applied in 
cases of aneurism or wound. 
Compression oj the subclavian artery is required in cases of operations about the shoulder, 
in the axilla, or at the upper part of the arm; and the student will observe that there is only 
one situation in which it can be effectually applied-viz., where the artery passes across the 
upper surface of the first rib. In order to compress the vessel in this situation, the shoulder 
should be depressed, and the surgeon, grasping the side or the neck, should press with his thumb 
in the angle formed by the posterior border of the Sterno-mastoid with the upper border of 
the clavicle, downward, backward, and inward against the rib; if from any cause the shoulder 
cannot be sufficiently depressed, pressure may be made from before backward, so as to compress 
the artery against the Scalenus medius muscle and the transverse process of the seventh cervical 
vertebra. In appropriate cases, a preliminary incision may be made through the cervical 
fascia, and the finger may be pressed down directly upon the artery. 
Ligature of the subclavian artery may be required in cases of wounds or of aneurism in 
the axilla, or in cases of aneurism on the cardiac side of the point of ligature; and the third part 
of the artery is that which is most favorable for an operation, on account of its being compara- 
tively superficial and most remote from the origin of the large branches. In those cases where 
the clavicle is not displaced, this operation may be performed with comparative facility; but 
where the clavicle is pushed up by a large aneurismal tumor in the axilla the artery is placed at 
a great depth from the surface, which materially increases the difficulty of the operation. Under 
these circumstances it becomes a matter of importance to consider the height to which this 
vessel reaches above the bone. In ordinary cases its arch is about half an inch above the clavicle, 
occasionally it is as high as an inch and a half, and sometimes so low as to be on a level with 
the upper border of the clavicle. If the clavicle is displaced, these variations will necessarily 
make the operation more or less difficult according as the vessel is more or less accessible. 
The chief points in the operation of tying the third portion of the subclavian artery are as 
follows: The patient being placed on a table in the supine position, with the head drawn over to 
the opposite side and the shoulder depressed as much as possible, the integument should be 
drawn downward over the clavicle, and an incision made through it, upon that bone, from the 
anterior border of the Trapezius to the posterior border of the Sterno-mastoid, to which may be 
added a short vertical incision meeting the inner end of the preceding. The object in drawing 
the skin downward is to avoid any risk of wounding the external jugular vein, for as it perforates 
the deep fascia above the clavicle, it cannot be drawn downward with the skin. The soft parts 
should now be allowed to glide up, and the cervical fascia should be divided upon a director, 
and if the interval between the Trapezius and Sterno-mastoid muscles be insufficient for the per- 636 
THE BLOOD-VASCULAR SYSTEM 
formance of the operation, a portion of one or both may be divided. The external jugular vein 
will now be seen toward the inner side of the wound: this and the suprascapular and transverse 
cervical veins, which terminate in it, should be held aside. If the external jugular vein is at all 
in the way and exposed to injury, it should be tied in two places and divided. The suprascapu- 
lar artery should be avoided, and the Omo-hyoid muscle held aside if necessary. In the space 
beneath this muscle careful search must be made for the vessel: a deep layer of fascia and some 
connective tissue having been divided carefully, the outer margin of the Scalenus anticus muscle 
must be felt for, and, the finger being guided by it to the first rib, the pulsation of the subcla- 
vian artery will be felt as it passes over the rib. The sheath of the vessels having been opened, 
the aneurism needle may then be passed around the artery from above downward and inward, so 
as to avoid including any of the branches of the brachial plexus. If the clavicle is so raised by 
the tumor that the application of the ligature cannot be effected in this situation, the artery may 
be tied above the first rib, or even behind the Scalenus anticus muscle; the difficulties of the 
operation in such a case will be materially increased, on account of the greater depth of the artery 
and the alteration in position of the surrounding parts. 
The second part of the subclavian artery, from being that portion which rises highest in 
the neck, has been considered favorable for the application of the ligature when it is difficult to 
tie the artery in the third part of its course. There are, however, many objections to the opera- 
tion in this situation. It is necessary to divide the Scalenus anticus muscle, upon which lies 
the phrenic nerve, and at the inner side of which is situated the internal jugular vein; and a 
wound of either of these structures might lead to the most dangerous consequences. Again, 
the artery is in contact, below, with the pleura, which must also be avoided; and, lastly, the 
proximity of so many of its large branches arising internal to this point must be a still further 
objection to the operation. In cases, however, where the sac of an axillary aneurism encroaches 
on the neck, it may be necessary to divide the outer half or two-thirds of the Scalenus anticus 
muscle, so as to place the ligature on the vessel at a greater distance from the sac. The opera- 
tion is performed exactly in the same way as a ligature of the third portion, until the Scalenus 
anticus is exposed, when it is to be divided on a director (never to a greater extent than its outer 
two-thirds), and it immediately retracts. The operation is therefore merely an extension of 
ligature of the third portion of the vessel. 
In those cases of aneurism of the axillary or subclavian artery in which the aneurism 
encroaches upon the outer portion of the Scalenus muscle to such an extent that a ligature 
cannot be applied in that situation, it may be deemed advisable, as a last resource, to tie the 
first portion of the subclavian artery. On the left side this operation has been regarded as 
almost impracticable; the great depth of the artery from the surface, its intimate relation 
with the pleura, and its close proximity to the thoracic duct and to so many important veins 
and nerves, present a series of difficulties which it is very difficult to overcome. Nevertheless, 
Professor Halsted and Schumpert have each tied successfully the first portion of the left sub- 
clavian for aneurism. J. K. Rodgers, of New York, also did it successfully. On the right 
side the operation is practicable, and has been performed. Dr. Nassau, of Philadelphia, suc- 
cessfully ligated the first part of the right subclavian. The main objection to the operation 
in this situation is the smallness of the interval which usually exists between the com- 
mencement of the vessel and the origin of the nearest branch. The operation may be per- 
formed in the following manner: The patient being placed on the table in the supine position 
with the neck extended, an incision should be made along the upper border of the inner part 
of the clavicle, and a second along the inner border of the Sterno-mastoid, meeting the 
former at an angle. The attachment of both heads of the Sterno-mastoid must be divided 
on a director and turned outward; a few small arteries and veins, and occasionally the 
anterior jugular vein, must be avoided, or, if necessary, ligatured in two places and divided, 
and the Sterno-hyoid and Sterno-thyroid muscles are to be divided in the same manner as the 
preceding muscle. After tearing through the deep fascia with the finger-nail, the internal jugular 
vein will be seen crossing the subclavian artery; this should be pressed aside and the artery 
secured by passing the needle from below upward, by which the pleura is more effectually 
avoided. The exact position of the vagus, the recurrent laryngeal, the phrenic and sympa- 
thetic nerves should be remembered, and the ligature should be applied near the origin of the 
vertebral, in order to afford as much room as possible for the formation of a coagulum 
between the ligature and the orgin of the vessel. It should be remembered that the right sub- 
clavian artery is occasionally deeply placed in the first part of its course when it arises from 
the left side of the aortic arch, and passes in such cases behind the oesophagus or between it 
and the trachea. 
Collateral Circulation.-After ligature of the third part of the subclavian artery the col- 
lateral circulation is mainly established by three sets of vessels, thus described in a dissection: 
"1. A posterior set, consisting of the suprascapular and posterior scapular branches of the 
subclavian, anastomosing with the subscapular from the axillary. 
"2. An internal set produced by the connection of the internal mammary on the one hand, 
with the superior and long thoracic arteries, and the branches from the subscapular on the other. THE SUBCLAVIAN ARTERY 
637 
" 3. A middle or axillary set, which consisted of a number of small vessels derived from branches 
of the subclavian, above, and, passing through the axilla, terminated either in the main trunk 
or some of the branches of the axillary below. This last set presented most conspicuously the 
peculiar character of the newly formed or, rather, dilated arteries, being excessively tortuous, 
and forming a complete plexus. 
"The chief agent in the restoration of the axillary artery below the tumor was the subscapular 
artery, which communicated most freely with the internal mammary, suprascapular, and pos- 
terior scapular branches of the subclavian, from all of which is received so great an influx of 
blood as to dilate it to three times its natural size."1 
When a ligature is applied to the first part of the subclavian aretry, the collateral circulation 
is carried on by-1, the anastomosis between the superior and inferior thyroid; 2, the anasto- 
mosis of the two vertebrals; 3, the anastomosis of the internal mammary with the deep epi- 
gastric and the aortic intercostals; 4, the superior intercostal anastomosing with the aortic inter- 
costals; 5, the profunda cervicis anastomosing with the princeps cervicis; 6, the scapular branches 
of the thyroid axis anastomosing with the branches of the axillary; and 7, the thoracic branches 
of the axillary anastomosing with the aortic intercostals. 
Branches.-The branches given off from the subclavian artery are: 
Vertebral. 
Thyroid axis. 
Internal mammary. 
Superior intercostal. 
On the left side all four branches generally arise from the first portion of the 
vessel; but on the right side, the superior intercostal usually arises from the second 
portion of the vessel. On both sides of the body the first three branches arise close 
together at the inner margin of the Scalenus anticus; in the majority of cases a 
free interval of from half an inch to an inch exists between the commencement of 
the artery and the origin of the nearest branch; in a smaller number of cases an 
interval of more than an inch exists, but it never exceeds an inch and three-quarters. 
Ina very few instances the interval has been found to be less than half an inch. 
The vertebral artery arises from the upper and posterior part of the subclavian 
artery, the internal mammary from the lower part of the artery; the thyroid axis 
from in front and the superior intercostal from behind. 
The Vertebral Artery (a. vertebralis) (Fig. 399) is generally the first and 
largest branch of the subclavian; it arises from the upper and back part of the 
first portion of the vessel, and, passing upward, enters the foramen in the trans- 
verse process of the sixth cervical vertebra,2 and ascends through the foramina 
in the transverse processes of all the vertebra? above this. Above the upper border 
of the axis it inclines outward and upward to the foramen in the transverse process 
of the atlas, through which it passes; it then winds backward behind its articular 
process, runs in a deep groove on the upper surface of the posterior arch of this 
bone (Fig. 16), and, passing beneath the posterior occipito-atlantal ligament 
(Figs. 199 and 202), pierces the dura mater and arachnoid, and enters the skull 
through the foramen magnum. It then passes forward and upward, inclining 
from the lateral aspect to the front of the medulla oblongata. It unites in the 
middle line with the vessel of the opposite side at the lower border of the pons 
Varolii to form the basilar artery (Fig. 401). 
Relations.-At its origin it is situated behind the internal jugular and vertebral 
veins, and is crossed by the inferior thyroid artery: it lies between the Longus 
colli and Scalenus anticus muscles, having the thoracic duct in front of it on the 
left side. It rests on the transverse process of the seventh cervical vertebra and 
the sympathetic nerve. Within the foramina formed by the transverse processes 
of the vertebrae it is accompanied by a plexus of nerves from the inferior cervical 
ganglion of the sympathetic, and is surrounded by a dense plexus of veins which 
unite to form the vertebral vein at the lower part of the neck. It is situated in 
1 Guy's Hospital Reports, vol. i.. 1836: case of axillary aneurism, in which Mr. Aston Key had tied the sub- 
clavian artery on the outer edge of the Scalenus muscle twelve years previously. 
2 The vertebral artery sometimes enters the foramen in the transverse process of the fifth vertebra. Dr. Smyth, 
who tied this artery in the living subject, found it, in one of his dissections, passing into the foramen in the 
seventh vertebra.-Ed. of 15th English edition. 638 
THE BLOOD-VASCULAR SYSTEM 
front of the cervical nerves, as they issue from the intervertebral foramina. While 
winding round the articular process of the atlas, it is contained in a triangular 
space, the suboccipital triangle, formed by the Rectus capitis posticus major, the 
Superior oblique and the Inferior oblique muscles; and at this point is covered 
by the Complexus muscle (Fig. 283). The suboccipital nerve here lies between 
the artery and the bone. Within the skull, as the artery winds round the medulla 
oblongata, it is placed between the hypoglossal nerve and the anterior root of the 
suboccipital nerve, beneath the first digitation of the ligamentmn denticulatum, 
and finally ascends between the basilar process of the occipital bone and the 
anterior surface of the medulla oblongata. 
Branches.-These may be divided into two sets-those given off in the neck 
and those within the cranium. 
Cervical Branches. 
Lateral Spinal. 
Muscular. 
Cranial Branches. 
Posterior Meningeal. 
Anterior Spinal. 
Posterior Spinal. 
Posterior Inferior Cerebellar. 
Bulbar. 
The Lateral Spinal Branches (rami spinales) enter the spinal canal through the 
intervertebral foramina and divide into two branches. Of these, one passes along 
the roots of the nerves to supply the spinal cord and its membranes, anastomosing 
with the other arteries of the spinal cord; the other divides into an ascending and 
a descending branch, which unite with similar branches from the artery above and 
below, so that two lateral anastomotic chains are formed on the posterior surface 
of the bodies of the vertebrae near the attachment of the pedicles. From these 
anastomotic chains branches are given off to supply the periosteum and the bodies 
of the vertebrae, and to communicate with similar branches from the opposite side; 
from these communicating branches small branches are given off which join 
similar branches above and below, so that a central anastomotic chain is formed 
on the posterior surface of the bodies of the vertebrae. 
Muscular Branches are given off to the deep muscles of the neck, where the 
vertebral artery curves round the articular process of the atlas. They anastomose 
with the occipital and with the ascending and deep cervical arteries. 
The Posterior Meningeal (ramus meningeus) is a small branch given off from 
the vertebral opposite the foramen magnum. It ramifies between the bone and 
dura mater in the cerebellar fossa*, and supplies the falx cerebelli. 
The Anterior Spinal (a. spinalis anterior) is a small branch which arises near 
the termination of the vertebral, and, descending in front of the medulla oblongata, 
unites with its fellow on the opposite side at about the level of the foramen magnum. 
One of these vessels is usually larger than the other, but occasionally they are about 
equal in size. The single trunk thus formed descends on the front of the spinal 
cord, and is reinforced by a succession of small branches which enter the spinal 
canal through the intervertebral foramina; these branches are derived from the 
vertebral artery and the ascending cervical branch of the inferior thyroid artery 
in the neck; from the intercostal in the dorsal region; and from the lumbar, 
ilio-lumbar, and lateral sacral arteries in the lower part of the spine. They unite, 
by means of ascending and descending branches, to form a single anterior median 
artery, which extends as far as the lower part of the spinal cord. This vessel is 
placed in the pia mater along the anterior median fissure; it supplies that mem- 
brane and the substance of the cord, and sends off branches at its lower part to 
be distributed to the cauda ecpiina, and ends on the central fibrous prolongation 
of the cord. THE SUBCLAVIAN ARTERY 
639 
The Posterior Spinal (a. spinalis posterior) arises from the vertebral at the side 
of the medulla oblongata: passing backward to the posterior aspect of the spinal 
cord, it descends on each side, lying behind the posterior roots of the spinal 
nerves, and is reinforced by a succession of small branches which enter the 
spinal canal through the intervertebral foramina, and by which it is continued to 
the lower part of the cord and to the cauda equina. Branches from these vessels 
form a free anastomosis round the posterior roots of the spinal nerves, and com- 
municate, by means of very tortuous transverse branches, with the vessel of the 
opposite side. At its commencement it gives off an ascending branch, which 
terminates on the side of the fourth ventricle. 
The Posterior Inferior Cerebellar Artery (a. cerebelli injerior posterior) (Fig. 401), 
the largest branch of the vertebral, winds backward round the upper part of the 
medulla oblongata, passing between the origin of the pneumogastric and spinal 
accesssory nerves, over the restiform body to the under surface of the cerebellum, 
where it divides into two branches-an internal, which is continued backward 
to the notch between the two hemispheres of the cerebellum; and an external, 
which supplies the under surface of the cerebellum as far as its outer border, 
where it anastomoses with the anterior inferior cerebellar and the superior cere- 
bellar branches of the basilar artery. Branches from this artery supply the 
choroid plexus of the fourth ventricle. 
The Bulbar Arteries comprise several minute vessels which spring from the 
vertebral and its branches and are distributed to the medulla oblongata. 
Surgical Anatomy.-The vertebral artery has been tied in several instances: 1, for wounds 
or traumatic aneurism; 2, after ligation of the innominate, either immediately to prevent hem- 
orrhage, or later on to arrest bleeding where it has occurred at the seat of ligation; and 3, 
in epilepsy. In these latter cases the treatment has been recommended by Dr. Alexander, of 
Liverpool, in the hope that by diminishing the supply of blood to the posterior part of the brain 
and the spinal cord.a diminution or cessation of the epileptic fits would result. But, on account 
of the uncertainty as to what cases, if any, derived benefit from the operation, it has now been 
abandoned as a treatment for epilepsy. The operation of ligation of the vertebral is performed 
by making an incision along the posterior border of the Sterno-mastoid muscle, just above the 
clavicle. The muscle is pulled to the inner side, and the anterior tubercle of the transverse 
process of the sixth cervical vertebra is sought for. A deep layer of fascia being now divided, 
the interval between the Scalenus anticus and the Longus colli muscles just below their attach- 
ment to the tubercle is defined, and the artery and vein are found in the interspace. The vein 
is to be drawn to the outer side, and the aneurism needle is passed from without inward. Drs. 
Ramskill and Bright have pointed out that severe pain at the back of the head may be symp- 
tomatic of disease of the vertebral artery just before it enters the skull. This is explained by 
the close connection of the artery with the suboccipital nerve in the groove on the posterior 
arch of the atlas. Disease of the same artery has been also said to affect speech, from pressure 
on the hypoglossal nerve where it is in relation with the vessel, leading to paralysis of the muscles 
of the tongue. 
The Basilar Artery (a. hasilaris) (Fig. 401), so named from its position at the 
base of the skull, is a single trunk formed by the junction of the two vertebral 
arteries; it extends from the posterior to the anterior border of the pons Varolii, 
lying in the median pontine groove, under cover of the arachnoid. It ends by 
dividing into the two posterior cerebral arteries. 
Branches.-Its branches are, on each side, the following: 
Transverse. 
Internal Auditory. 
Anterior Inferior Cerebellar. 
Superior Cerebellar. 
Posterior Cerebral. 
The Transverse or Pontal Branches (rami ad pontem) supply the substance of 
the pons Varolii. 
The Internal Auditory (a. auditiva interna) accompanies the auditory nerve 
into the internal auditory meatus. It supplies the internal ear. 640 
THE BLOOD-VASCULAR SYSTEM 
The Anterior Inferior Cerebellar Artery (a. cerebelli inferior anterior) passes back- 
ward across the crus cerebelli, to be distributed to the anterior border of the under 
surface of the cerebellum, anastomosing with the posterior inferior cerebellar 
branch of the vertebral. 
The Superior Cerebellar Artery (a. cerebelli superior) on each side arises near 
the termination of the basilar. It passes outward, immediately behind the third 
nerve, which separates it from the posterior cerebral, winds round the crus 
cerebri, close to the fourth nerve, and, arriving at the upper surface of the 
cerebellum, divides into branches which ramify in the pia mater and, reaching 
the circumference of the cerebellum, anastomose with the branches of the inferior 
cerebellar arteries. Several branches are given to the pineal gland, the valve of 
Vieussens, and the velum interpositum. 
The Posterior Cerebral Artery (a. cerebri posterior) (Figs. 401,403,404, and 406), on 
each side, is the terminal branch of the basilar. It is larger than the preceding, from 
which it is separated near its origin by the third nerve. Passing outward, parallel 
to the superior cerebellar artery, and receiving the posterior communicating from 
the internal carotid, it winds round the crus cerebri, and passes to the under surface 
of the occipital lobes of the cerebrum, and break up into branches for the supply of 
the temporal and occipital lobes. The branches of the posterior cerebral artery are: 
Postero-median ganglionic. 
Posterior choroid. 
Postero-lateral ganglionic. 
Anterior temporal. 
Posterior temporal. 
Occipital. 
Three terminal 
The postero-median ganglionic branches (Fig. 406) are a group of small arteries 
which arise at the commencement of the posterior cerebral artery; these, with simi- 
lar branches from the posterior communicating, pierce the posterior perforated 
space, and supply the internal surfaces of the optic thalamus and the walls of the 
third ventricle. The posterior choroid enters the interior of the brain beneath the 
splenium of the corpus callosum, and supplies the velum interpositum and the 
choroid plexus. The postero-lateral ganglionic branches are a group of small 
arteries which arise from the posterior cerebral artery, after it has turned round the 
crus cerebri; they supply a considerable portion of the optic thalamus. The 
terminal branches are distributed as follows: the first, or the anterior temporal 
branches, to the under surface of the anterior portion of the temporal lobe; the 
second, or the posterior temporal branches, to the external occipital and the third 
temporal convolutions; and the third, or the occipital branches, to the inner and 
outer surfaces of the occipital lobe. 
Circle of Willis (circidus arteriosus [Willisi]).-The remarkable anastomosis 
which exists between the branches of the internal carotid and vertebral arteries at 
the base of the brain constitutes the circle of Willis. It is formed in front, by the 
anterior cerebral arteries, branches of the internal carotid, which are connected 
together by the anterior communicating; behind, by the two posterior cerebrals, 
branches of the basilar, which are connected on each side with the internal carotid 
by the posterior communicating arteries (Fig. 401). It is by this anastomosis 
that the cerebral circulation is equalized, and provision made for effectually 
carrying it on if one or more of the branches are obliterated. The parts of the 
brain included within this arterial circle are-the lamina cinerea, the commissure 
of the optic nerves, the infundibulum, the tuber cinereum, the corpora albicantia, 
and the posterior perforated space. 
The Thyroid Axis (truncus thyreocervicalis) (Figs. 392 and 410) is a short thick 
trunk which arises from the forepart of the first portion of the subclavian artery, 
close to the inner border of the Scalenus anticus muscle, and divides, almost 
immediately after its origin, into three branches-the inferior thyroid, supra- 
scapular, and transversalis colli. THE SUBCLAVIAN ARTERY 
641 
The Inferior Thyroid Artery (a. thyreoidea inferior) (Fig. 392) passes upward, in 
front of the vertebral artery and Longus colli muscle; then turns inward behind the 
sheath of the common carotid artery and internal jugular vein, and also behind 
the sympathetic nerve, the middle cervical ganglion resting upon the vessel, and 
reaching the lower border of the lateral lobe of the thyroid gland it divides into 
two branches, which supply the posterior and under part of the organ, and anasto- 
mose in its substance with the superior thyroid and with the corresponding artery 
of the opposite side. (See page 602.) The recurrent laryngeal nerve passes upward, 
generally behind but occasionally in front of the artery. Its branches are: 
Inferior Laryngeal. 
Tracheal. 
(Esophageal. 
Ascending Cervical. 
Muscular. 
The inferior laryngeal branch (a. laryngea inferior) ascends upon the trachea 
to the back part of the larynx, in company with the recurrent laryngeal nerve, 
and supplies the muscles and mucous membrane of this part, anastomosing with 
the laryngeal branch from the superior thyroid artery and with the inferior laryn- 
geal branch from the opposite side. The tracheal branches (rami trach eales) are 
distributed upon the trachea, anastomosing below with the bronchial arteries. 
The oesophageal branches (rami oesophayei) are distributed to the oesophagus, 
and anastomose with the oesophageal branches of the aorta. The ascending 
cervical (a. cervicalis ascendens) is a small branch which arises from the inferior 
thyroid just where that vessel is passing behind the common carotid artery, and 
runs up on the anterior tubercles of the transverse processes of the cervical 
vertebrae in the interval between the Scalenus anticus and Rectus capitis anticus 
major muscles. It gives muscular branches (rami musculares) to the muscles of 
the neck, which anastomose with branches of the vertebral, and sends one or two 
branches (rami spinales) into the spinal canal through the intervertebral foramina 
to be distributed to the spinal cord and its membranes, and to the bodies of the 
vertebrae in the same manner as the lateral spinal branches from the vertebral. 
It anastomoses with the ascending pharyngeal and occipital arteries. The mus- 
cular branches supply the depressors of the hyoid bone, the Longus colli, the 
Scalenus anticus, and the Inferior constrictor of the pharynx. One of the mus- 
cular branches passes between the transverse processes of the fourth and fifth 
cervical vertebrae and reaches the deep muscles of the neck. It is called the 
ramus profundus. 
Surgical Anatomy.-The inferior thyroid artery has been tied, in conjunction with the 
superior thyroid, in cases of bronchocele. An incision is made along the anterior border of the 
Sterno-mastoid down to the clavicle. After the deep fascia has been divided, the Sterno-mas- 
toid and carotid vessels are drawn outward and the carotid tubercle (Chassaignac's tubercle') 
sought for. The vessel will be found just below this tubercle, between the carotid sheath on the 
outer side of the trachea and oesophagus on the inner side. In passing the ligature great care 
must be exercised to avoid including the recurrent laryngeal nerve, which is occasionally found 
crossing in front of the vessel. Before extirpating a goitrous lobe of the thyroid the superior 
and inferior thyroid arteries of the diseased side are to be ligated. 
The Suprascapular or Transversalis Humeri Artery (a. transversa scapula?) (Figs. 392 
and 409), smaller than the tranversalis colli, passes obliquely from within outward, 
across the root of the neck. It at first passes downward and outward across the 
Scalenus anticus muscle and phrenic nerve, being covered by the Sterno-mastoid; 
it then crosses the subclavian artery and the cords of the brachial plexus, and runs 
outward, behind and parallel with the clavicle and Subclavius muscle, and beneath 
the posterior belly of the Omo-hyoid, to the superior border of the scapula, where 
it passes over the transverse ligament of the scapula, which separates it from the 
suprascapular nerve, and reaches the supraspinous fossa. In this situation it lies 
close to the bone, and ramifies between it and the Supraspinatus muscle, to which it 642 
THE BLOOD-VASCULAR SYSTEM 
supplies branches. It then passes downward behind the neck of the scapula, to 
reach the infraspinous fossa, where it anastomoses with the dorsalis scapula? branch 
of the subscapular artery and branches of the posterior scapular arteries. Besides 
distributing branches to the Sterno-mastoid, Subclavius, and neighboring muscles, 
it gives off a suprasternal branch, which crosses over the sternal end of the clavicle to 
the skin of the upper part of the chest; and a supra-acromial branch (ramus acro- 
mialis), which, piercing the Trapezius muscle, supplies the skin over the acromion, 
anastomosing with the acromial thoracic artery. As the artery passes over the trans- 
verse ligament of the 'scapula, a branch descends into the subscapular fossa, 
ramifies beneath the subscapular muscle, and anastomoses with the posterior and 
subscapular arteries. The suprascapular artery also sends branches to the 
acromio-clavicular and shoulder joints, and a nutrient artery to the clavicle. 
Posterior scapular. 
Suprascapular. 
A cromial branch 
of Thoracico-acromialis. 
Anterior 
^circumflex. 
■ Termination of 
subscapular. 
Fig. 409.-The scapular and circumflex arteries. 
The Transverse Cervical or Transversalis Colli Artery (a. transver sa colli) (Fig. 392) 
passes transversely outward, across the upper part of the subclavian triangle, to 
the anterior margin of the Trapezius muscle, beneath which it divides into two 
branches, the superficial cervical and the posterior scapular. In its passage across 
the neck it crosses in front of the phrenic nerve, Scaleni muscles, and the brachial 
plexus, between the divisions of which it sometimes passes, and is covered by the 
Platysma, Sterno-mastoid, Omo-hyoid, and Trapezius muscles. The superficial 
cervical (ramus ascendens) ascends beneath the anterior margin of the Trapezius, 
distributing branches to it and to the neighboring muscles and glands in the neck, 
and anastomosing with the superficial branch of the arteria princeps cervicis. The 
posterior scapular (ramus descendens) (Fig. 409) passes beneath the Levator anguli 
scapulje muscle to the superior angle of the scapula, and then descends along the 
posterior border of that bone as far as the inferior angle. In its course it is 
covered by the Rhomboid muscles, supplying them and the Latissimus dorsi and 
Trapezius, and anastomosing with the suprascapular and subscapular arteries, 
and with the posterior branches of some of the intercostal arteries. 
Peculiarities.-The superficial cervical frequently arises as a separate branch from the thyroid 
axis; and the posterior scapular, from the third, more rarely from the second, part of the sub- 
clavian. THE SUBCLAVIAN AETERY 
643 
The Internal Mammary (a. mammaria interna) (Fig. 410) arises from the 
under surface of the first portion of the subclavian artery, opposite the thyroid 
Thyroid axis. 
Scalenus 
anticus. 
Common carotid. 
'Innominate. 
■Internal mam- 
mary. 
Anterior intercostal 
branches. 
Perforating 
branches. 
.Superior epi- 
gastric. 
Musculo- 
phrenic.. 
■Deep epi- 
gastric. 
-External 
iliac. 
Fig. 410.-Tho internal mammary artery and its branches. 
axis. It passes downward and inward behind the costal cartilage of the first rib 
to the inner surface of the anterior wall of the chest, resting against the costal 
cartilages about half an inch from the margin of the sternum; and, at the interval 644 
THE BLOOD-VASCULAR SYSTEM 
between the sixth and seventh cartilages, divides into two branches, the musculo- 
phrenic and superior epigastric. 
Relations.-At its origin it is covered by the internal jugular and subclavian 
veins, and as it enters the thorax is crossed from without inward by the phrenic 
nerve, and then passes forward close to the outer side of the innominate vein. In 
the upper part of the thorax it lies behind the costal cartilages and Internal inter- 
costal muscles, and is crossed by the terminations of the upper six intercostal 
nerves. At first it lies upon the pleura, but at the lower part of the thorax the 
Triangularis sterni separates the artery from this membrane. It has two venre 
comites; these unite into a single vein, which joins the innominate vein of its own 
side. 
Branches.-The branches of the internal mammary are- 
Comes Nervi Phrenici (Superior Phrenic) 
Mediastinal. 
Pericardiac. 
Sternal. 
Anterior Intercostal. 
Perforating. 
Musculo-phrenic. 
Superior Epigastric. 
The Comes Nervi Phrenici or Superior Phrenic (a. pericardiacophrenica) is a long 
slender branch which accompanies the phrenic nerve, between the pleura and 
pericardium, to the Diaphragm. It gives branches to the pericardium and is 
distributed upon the Diaphragm, anastomosing with the other phrenic branches 
from the internal mammary and with phrenic branches of the abdominal aorta. 
The Mediastinal Branches (an. mediastinales anteriores) are small vessels 
which are distributed to the areolar tissue and lymphatic glands in the anterior 
mediastinum and to the remains of the thymus gland. 
The Pericardiac Branches supply the upper part of the anterior surface of the 
pericardium, the lower part receiving branches from the musculo-phrenic artery. 
The Sternal Branches (rami sternales') are distributed to the Triangularis sterni 
and to the posterior surface of the sternum. 
The mediastinal, pericardiac, and sternal branches, together with some twigs 
from the comes nervi phrenici, anastomose with branches from the intercostal and 
bronchial arteries, and form a minute plexus beneath the pleura, which has been 
named by Turner the subpleural mediastinal plexus. 
The Anterior Intercostal Arteries (rami intercostales) supply the five or six upper 
intercostal spaces. The branch corresponding to each space soon divides into 
two, or the two branches may come off separately from the parent trunk. The 
small vessels pass outward in the intercostal spaces, one, the larger, lying near 
the lower margin of the rib above, and the other, the smaller, near the upper 
margin of the rib below, and anastomose with the intercostal arteries from the 
aorta. They are at first situated between the pleura and the Internal intercostal 
muscles, and then between the Internal and External intercostal muscles. They 
supply the Intercostal muscles, and, by branches which perforate the External 
intercostal muscle, reach the Pectoral muscles and the mammary gland. 
The Perforating or Anterior Perforating Arteries (rami perforantes) correspond 
to the five or six upper intercostal spaces. They arise trom the internal mam- 
mary, pass forward through the intercostal spaces, and, curving outward, supply 
the Pectoralis major and the integument. Those which correspond to the second, 
third, and fourth spaces are distributed to the mammary gland. In females, 
during lactation, these branches are of large size. 
The Musculo-phrenic Artery (a. musculo phrenica) is directed obliquely down- 
ward and outward, behind the cartilages of the false ribs, perforating the Dia- 
phragm at the eighth or ninth rib, and terminating, considerably reduced in size, 
opposite the last intercostal space. It gives off anterior intercostal arteries to 
each of the intercostal spaces across which it passes; these diminish in size as the SURGICAL ANATOMY OF THE AXILLA 
645 
spaces decrease in length, and are distributed in a manner precisely similar to 
the anterior intercostals from the internal mammary. The musculo-phrenic also 
gives branches to the lower part of the pericardium, and others which run back- 
ward to the Diaphragm and downward to the abdominal muscles. 
The Superior Epigastric (a. epigastrica superior) continues in the original direc- 
tion of the internal mammary; it descends through the cellular interval between 
the costal and sternal attachments of the Diaphragm, and enters the sheath of the 
Rectus abdominis muscle, at first lying behind the muscle, and then perforating 
it and supplying it, and anastomosing with the deep epigastric artery from the 
external iliac. Some branches perforate the sheath of the Rectus, and supply the 
muscles of the abdomen and the integument, and a small branch, which passes 
inward upon the side of the ensiform appendix, anastomoses in front of that 
cartilage with the superior epigastric artery of the opposite side. It also gives 
some twigs to the Diaphragm, while from the artery of the right side small 
branches extend into the falciform ligament of the liver and anastomose with 
the hepatic artery. 
Surgical Anatomy.-The course of the internal mammary artery may be defined by draw- 
ing a line across the six upper intercostal spaces half an inch from and parallel with the sternum. 
The position of the vessel must be remembered, as it is liable to be wounded in stabs of the 
chest-wall. It is most easily reached by a transverse incision in the second intercostal space. 
The Superior Intercostal (truncus costocervicalis) (Figs. 399 and 416) arises from 
the upper and back part of the subclavian artery, behind the Scalenus anticus mus- 
cle on the right side and to the inner side of that muscle on the left side. Passing 
backward, it gives off the deep cervical branch, and then descends behind the 
pleura in front of the necks of the first two ribs, and inosculates with the first 
aortic intercostal. As it crosses the neck of the first rib it lies to the inner side 
of the anterior division of the first dorsal nerve and to the outer side of the first 
thoracic ganglion of the sympathetic. In the first intercostal space it gives off a 
branch which is distributed in a manner similar to the distribution of the aortic 
intercostals. The branch for the second intercostal space usually joins with one 
from the highest aortic intercostal. Each intercostal gives off a branch to the 
posterior spinal muscles, and a small branch which passes through the corre- 
sponding intervertebral foramen to the spinal cord and its membranes. 
The Deep Cervical Branch (a. cervicalis profunda) arises, in most cases, from 
the superior intercostal, and is analogous to the posterior branch of an aortic 
intercostal artery; occasionally it arises as a separate branch from the sub- 
clavian artery. Passing backward, above the eighth cervical nerve and between 
the transverse process of the seventh cervical vertebra and the first rib, it runs 
up the back part of the neck, between the Complexus and Semispinalis colli 
muscles, as high as the axis vertebra, supplying these and adjacent muscles, and 
anastomosing with the deep branch of the arteria princeps cervicis of the occipital, 
and with branches which pass outward from the vertebral. It gives off a special 
branch which enters the spinal canal through the intervertebral foramen between 
the seventh cervical and first dorsal vertebrae. 
SURGICAL ANATOMY OF THE AXILLA. 
The axilla is a pyramidal space, situated between the upper and lateral part 
of the chest and the inner side of the arm. 
Boundaries.-Its apex, which is directed upward toward the root of the neck, 
corresponds to the interval between the first rib, the upper edge of the scapula, 
and the clavicle, through which the axillary vessels, the brachial plexus of nerves, 
and the long thoracic nerve pass. This interval is the cervico-axillary passage. 646 
THE BLOOD VASCULAR SYSTEM 
The base, directed downward, is formed by the integument and a thick layer of 
fascia, the axillary fascia (fascia axillaris) (Fig. 313), extending between the lower 
border of the Pectoralis major in front and the lower border of the Latissimus 
dorsi behind (page 463). The axillary fascia is perforated at several points. 
'The large central opening is called the foramen of Langer. The inner margin of 
the foramen of Langer is dense and constitutes a part of the axillary arch, 
which is a fibro-muscular slip derived from the latissimus dorsi. The axilla 
is broad internally at the chest, but narrow and pointed externally at the 
arm. The anterior boundary is formed by the Pectoralis major and minor mus- 
cles, the former covering the whole of the anterior wall of the axilla, the latter 
covering only its central part, the costo-coracoid membrane, the clavicle, and the 
Subclavius muscle. The posterior boundary, which extends somewhat lower 
than the anterior, is formed by the Subscapularis above, the Teres major and 
Latissimus dorsi below. On the inner side are the first four ribs with their 
corresponding Intercostal muscles, and part of the Serratus magnus. On 
the outer side, where the anterior and posterior boundaries converge, the space 
is narrow, and bounded by the humerus, the Coraco-brachialis and Biceps 
muscles. 
Contents.-This space contains the axillary vessels and brachial plexus of 
nerves, with their branches, some branches of the intercostal nerves, and a large 
number of lymphatic glands, all connected together by a quantity of fat and loose 
areolar tissue. 
Position of the Contents.-The axillary artery and vein, with the brachial plexus 
of nerves, extend obliquely along the outer boundary of the axillary space, from 
its apex to its base, and are placed much nearer the anterior than the posterior wall, 
the vein lying to the inner or thoracic side of the artery and partially concealing 
it. At the forepart of the axillary space, in contact with the Pectoral muscles, and 
along the anterior margin are the thoracic branches of the axillary artery, and 
along the lower margin of the Pectoralis minor the long thoracic artery extends 
to the side of the chest. At the back part, in contact with the lower margin of 
the Subscapularis muscle, are the subscapular vessels and nerves; winding around 
the outer border of this muscle is the dorsalis scapulae artery and veins; and, close 
to the neck of the humerus, the posterior circumflex vessels and the circumflex 
nerve are seen curving backward to the shoulder. 
Along the inner or thoracic side no vessel of any importance exists, the upper 
part of the space being crossed merely by a few small branches from the superior 
thoracic artery. There are some important nerves, however, in this situation- 
viz., the posterior thoracic or external respiratory nerve, descending on the sur- 
face of the Serratus magnus, to which it is distributed; and perforating the upper 
and anterior part of this wall, the intercosto-humeral nerve or nerves, passing 
across the axilla to the inner side of the arm 
The cavity of the axilla is filled by a quantity of loose areolar tissue and a large 
number of small arteries and veins, all of which are, however, of inconsiderable 
size, and numerous lymphatic glands, the position and arrangement of which are 
described on a subsequent page. 
Surgical Anatomy.-The axilla is a space of considerable surgical importance. It trans- 
mits the large vessels and nerves to the upper extremity, and these may be the seat of injury or 
disease: it contains numerous lymphatic glands which may require removal when diseased; in it 
is a quantity of loose connective and adipose tissue which may be readily infiltrated with blood 
or pus. The axilla may be the seat of rapidly growing tumors. Moreover, it is covered at its 
base by thin skin, largely supplied with sebaceous and sweat glands, which is frequently the 
seat of small cutaneous abscesses and boils, and of eruptions due to irritation. 
In suppuration in the axilla the arrangement of the fasciae plays a very important part in the 
direction which the pus takes. As described on page 464, the costo-coracoid membrane, after 
covering in the space between the clavicle and the upper border of the Pectoralis minor, splits 7772? AXILLARY ARTERY 
to enclose this muscle, and, reblending at its lower border, becomes incorporated with the axillary 
fascia at the anterior fold of the axilla. This is known as the clavi-pectoral jascia. Suppura- 
tion may take place either superficial to or beneath this layer of fascia; that is, either between 
the Pectorals or below the Pectoralis minor: in the former case, the pus would point either at the 
anterior border of the axillary fold or in the groove between the Deltoid and the Pectoralis major; 
in the latter, the pus would have a tendency to surround the vessels and nerves and ascend into 
the neck, that being the direction in which there is least resistance. Its progress toward the 
skin is prevented by the axillary fascia; its progress backward, by the Serratus magnus; forward, 
by the clavi-pectoral fascia; inward, by the wall of the thorax; and outward, by the upper limb. 
The pus in these cases, after extending into the neck, has been known to spread through the 
superior opening of the thorax into the mediastinum. 
In opening an axillary abscess the knife should be entered in the floor of the axilla, midway 
between the anterior and posterior margins and near the thoracic side of the space. It is well 
to use a director and dressing forceps after an incision has been made through the skin and fascia 
in the manner directed by the late Mr. Hilton. 
The student should attentively consider the relation of the vessels and nerves in the several 
parts of the axilla, for it is the universal plan, at the present day, to remove the glands from 
the axilla in operating for cancer oj the breast. In performing such an operation it will be 
necessary to proceed with much caution in the direction of the outer wall and apex of the space, 
647 
Anterior 
circumflex. 
Fig. 411.-The axillary artery and its branches. 
as here the axillary vessels will be in danger of being wounded. Toward the posterior wall it 
will be necessary to avoid the subscapular, dorsalis scapulae, and posterior circumflex vessels. 
Along the anterior wall it will be necessary to avoid the thoracic branches. In clearing out the 
axilla the axillary vein should be first defined and cleared up to the apex of the axilla. 
When the apex of the space is reached, all fat and glands must be carefully removed and the 
whole axilla cleared by separating the tissues along the inner and posterior walls, so that when 
the proceeding is completed, the axilla is cleared of all its contents except the main vessels and 
nerves. 
THE AXILLARY ARTERY (A. AXILLARIS) (Fig. 411). 
The axillary artery, the continuation of the subclavian, commences at the 
outer border of the first rib, and terminates at the lower border of the tendon 648 
THE BLOOD-VASCULAR SYSTEM 
of the Teres major muscle, where it takes the name of brachial. Its direction 
varies with the position of the limb: when the arm lies by the side of the 
chest, the vessel forms a gentle curve, the convexity being upward and outward; 
when the arm is directed at right angles with the trunk, the vessel is nearly 
straight; and when the arm is elevated still higher, the arteries describe a curve 
the concavity of which is directed upward. At its commencement the artery is 
very deeply situated, but near its termination it is superficial, being covered only 
by the skin and fascia. The description of the relations of this vessel is facili- 
tated by its division into three portions, the first portion being above the 
Pectoralis minor; the second portion behind; and the third below that muscle. 
Relations.-The first portion of the axillary artery is in relation, in front, with 
the clavicular portion of the Pectoralis major, the costo-coracoid membrane, the 
external anterior thoracic nerve, and the acromio-thoracic and cephalic veins; 
behind, with the first intercostal space, the corresponding Intercostal muscle, 
the second and a portion of the third digitation of the Serratus magnus, and the 
posterior thoracic and internal anterior thoracic nerves; on its outer side, with the 
brachial plexus, from which it is separated by a little cellular interval; on its inner 
or thoracic side, with the axillary vein, which overlaps the artery. 
Relations of the First Portion of the Axillary Artery. 
In front. 
Pectoral is major. 
Costo-coracoid membrane. 
External anterior thoracic nerve. 
Acromio-thoracic and cephalic veins, 
Outer side. 
Brachial plexus. 
Axillary 
Artery. 
First portion. 
Inner side. 
Axillary vein. 
First Intercostal space and Intercostal muscle. 
Second and third digitations of Serratus magnus. 
Posterior thoracic and Internal anterior thoracic nerves. 
Behind. 
The second portion of the axillary artery lies beyond the Pectoralis minor. It 
is covered, in front, by the Pectoralis major and minor muscles; behind, it is 
separated from the Subscapularis by a cellular interval; on the inner side is the 
axillary vein, separated from the artery by the inner cord of the plexus and the 
internal anterior thoracic nerve. The brachial plexus of nerves surrounds the 
artery on three sides, and separates it from direct contact with the vein and 
adjacent muscles. 
Relations of the Second Portion of the Axillary Artery. 
In front. 
Pectoralis major and minor. 
Outer side. 
Axillary 
Artery. 
Second 
portion. 
Inner side. 
Outer cord of plexus. 
Axillary vein. 
Inner cord of plexus. 
Internal anterior thoracic nerve. 
Subscapularis. 
Posterior cord of plexus. 
Behind. THE AXILLARY ARTERY 
649 
The third portion of the axillary artery lies below the Pectoralis minor. It is 
in relation, in front, with the lower part of the Pectoralis major above, being 
covered only by the integument and fascia below, where it is crossed by the inner 
head of the median nerve; behind, with the lower part of the Subscapularis and 
the tendons of the Latissimus dorsi and Teres major; on its outer side, with the 
Coraco-brachialis; on its inner or thoracic side, with the axillary vein. The nerves 
of the brachial plexus bear the following relation to the artery in this part of its 
course: on the outer side is the median nerve, and the musculo-cutaneous for a 
short distance; on the inner side, the ulnar nerve (between the vein and artery) 
and the lesser internal cutaneous nerve (to the inner side of the vein); in front 
is the internal cutaneous nerve, and behind, the musculo-spiral and circumflex, the 
latter extending only to the lower border of the Subscapularis muscle. 
Relations of the Third Portion of the Axillary Artery 
In front. 
Integument and fascia. 
Pectoralis major. 
Inner head of median nerve. 
Internal cutaneous nerve. 
Outer side. 
Coraco-brachialis. 
Median nerve. 
Musculo-cutaneous nerve. 
Inner side. 
Ulnar nerve. 
Axillary vein. 
Lesser internal cutaneous nerve. 
Axillary 
Artery. 
Third portion. 
Behind. 
Subscapularis. 
Tendons of Latissimus dorsi and Teres major. 
Musculo-spiral and circumflex nerves. 
Peculiarities.-The axillary artery, in about one case out of every ten, gives off a large 
branch, which forms either one of the arteries of the forearm or a large muscular trunk. In the 
first set of cases this artery is most frequently the radial (1 in 33), sometimes the ulnar (1 in 72), 
and, very rarely, the interosseous (1 in 506). In the second set of cases the trunk has been 
found to give origin to the subscapular, circumflex, and profunda arteries of the arm. Some- 
times only one of the circumflex, or one of the profunda arteries, arose from the trunk. In 
these cases the brachial plexus surrounded the trunk of the branches and not the main vessel. 
Surface Marking.-The course of the axillary artery may be marked out by raising the 
arm to a right angle with the body and drawing a line from the middle of the clavicle to the 
point where the tendon of the Pectoralis major crosses the prominence caused by the Coraco- 
brachialis as it emerges from under cover of the anterior fold of the axilla. The third portion 
of the artery can be felt pulsating beneath the skin and fascia, at the junction of the anterior 
with the middle third of the space between the anterior and posterior folds of the axilla, close to 
the inner border of the Coraco-brachialis muscle. 
Surgical Anatomy.-The student, having carefully examined the relations of the axillary 
artery in its various parts, should now consider in what situation compression of this vessel 
may be most easily effected, and the best position for the application of a ligature to it when 
necessary. 
Compression of the vessel may be required in the removal of tumors or in amputation of 
the upper part of the arm; and the only situation in which this can be effectually made is in the 
lower part of its course; by pressing on it in this situation from within outward against the 
humerus the circulation may be effectually arrested. 
The axillary artery is perhaps more frequently lacerated than any other artery in the body, 
with the exception of the popliteal, by violent movements of the extremity, especially in those 
cases where its coats are diseased. It has occasionally been ruptured in attempts to reduce old 
dislocations of the shoulder-joint. This accident is most likely to occur during the preliminary 
breaking down of adhesions, in consequence of the artery having become fixed to the capsule 
of the joint. Aneurism of the axillary artery is of frequent occurrence, a large percentage of 
the cases being traumatic in their origin, due to the violence to which the vessel is exposed in 
the varied, extensive, and often violent movements of the limb. 
The application of a ligature to the axillary artery may be required in cases of 
aneurism of the upper part of the brachial or as a distal operation for aneurism of the sub- 650 
THE BLOOD-VASCULAR SYSTEM 
clavian; and there are only two situations in which the vessel can be secured-viz., in the first 
and in the third parts of its course; for the axillary artery at its central part is so deeply seated, 
and, at the same time, so closely surrounded with large nerve trunks, that the application of a 
ligature to it in that situation would be almost impracticable. 
In the third part of its course the operation is most simple, and may be performed in the 
following manner: The patient being placed on a bed and the arm separated from the side, with 
the hand supinated, an incision about two inches in length is made through the integument 
forming the floor of the axilla, the cut being a little nearer to the anterior than the posterior 
fold of the axilla. After carefully dissecting through the areolar tissue and fascia, the median 
nerve and axillary vein are exposed; the former having been displaced to the outer and the 
latter to the inner side of the arm, the elbow being at the same time bent, so as to relax the 
structures and facilitate their separation, the ligature may be passed round the artery from the 
ulnar to the radial side. 
This portion of the artery is occasionally crossed by a muscular slip, the axillary arch, derived 
from the Latissimus dorsi, which may mislead the surgeon during an operation. The occasional 
existence of this muscular fasciculus was spoken of in the description of the muscles. It may 
easily be recognized by the transverse direction of its fibres. 
The first portion of the axillary artery may be tied in cases of aneurism encroaching so far 
upward that a ligature cannot be applied in the lower part of its course. Notwithstanding that 
this operation has been performed in some few cases, and with success, its performance is at- 
tended with much difficulty and danger. The student will remark that in this situation it would 
be necessary to divide a thick muscle, and, after incising the costo-coracoid membrane, the 
artery would be exposed at the bottom of a more or less deep space, with the cephalic and axil- 
lary veins in such relation with it as must render the application of a ligature to this part of 
the vessel particularly hazardous. Under such circumstances it is an easier, and at the same 
time more advisable, operation to tie the subclavian artery in the third part of its course. 
The vessel in the first part of its course can best be secured through a curved incision the 
convexity of which is downward. This incision passes from a point half an inch external to 
the sterno-clavicular joint to a point half an inch internal to the coracoid process. The limb 
is to be well abducted and the head inclined to the opposite side, and this incision is carried 
through the superficial structures, care being taken to avoid the cephalic vein at the outer angle 
of the incision. The clavicular origin of the Pectoralis major is then divided in the whole 
extent of the wound. The arm is now to be brought to the side, and the upper edge of the 
Pectoralis minor defined and drawn downward. The costo-coracoid membrane is to be care- 
fully divided close to the coracoid process, and the axillary sheath exposed; this is to be opened 
with especial care on account of the vein overlapping the artery. The needle should be passed 
from below, so as to avoid wounding the vein. 
In a case of wound of the vessel the general practice of cutting down upon and tying it above 
and below the wounded point should be adopted in all cases. 
Collateral Circulation after Ligature of the Axillary Artery.-If the artery be tied 
above the origin of the acromial thoracic, the collateral circulation will be carried on by the same 
branches as after the ligature of the subclavian; if at a lower point, between the acromial thoracic 
and subscapular arteries, the latter vessel, by its free anastomoses with the other scapular arteries, 
branches of the subclavian, will become the chief agent in carrying on the circulation, to which 
the long thoracic, if it be below the ligature, will materially contribute by its anastomoses with 
the intercostal and internal mammary arteries. If the point included in the ligature be below 
the origin of the subscapular artery, it will most probably also be below the origins of the cir- 
cumflex arteries. The chief agents in restoring the circulation will then be the subscapular and 
the two circumflex arteries anastomosing with the superior profunda from the brachial, which 
will be afterward referred to as performing the same office after ligation of the brachial. The 
cases in which the operation has been performed are few in number, and no published account 
of dissections of the collateral circulation appears to exist. 
Branches.-The branches of the axillary artery are- 
From first part 
Superior Thoracic. 
Acromial Thoracic. 
From second part 
Long Thoracic. 
Alar Thoracic. 
Subscapular. 
Posterior Circumflex. 
Anterior Circumflex. 
From third part 
The Superior Thoracic (a. thoracalis supremo) is a small artery which arises 
from the axillary separately or by a common trunk with the acromial thoracic. 
Running forward and inward along the upper border of the Pectoralis minor, it THE AXILLARY ARTERY 
651 
passes between it and the Pectoralis major to the side of the chest. It supplies 
these muscles and the parietes of the thorax, anastomosing with the internal mam- 
mary and intercostal arteries. 
The Acromial Thoracic or the Thoracic Axis (a. thoracoacromialis} is a 
short trunk which arises from the forepart of the axillary artery, its origin being 
generally overlapped by the upper edge of the Pectoralis minor. Projecting 
forward to the upper border of the Pectoralis minor, it divides into four sets of 
branches-thoracic, acromial, descending, and clavicular. 
The Thoracic Branches (rami pectorales}, two or three in number, are distributed 
to the Serratus magnus and Pectoral muscles, anastomosing with the intercostal 
branches of the internal mammary. 
The Acromial Branch (ramus acromialis} is directed outward toward the acro- 
mion, supplying the Deltoid muscle, and anastomosing, on the surface of the 
acromion, with the suprascapular and posterior circumflex arteries. 
The Descending or Humeral Branch (ramus deltoideus} passes in the space between 
the Pectoralis major and Deltoid, in the same groove as the cephalic vein, and 
supplies both muscles. 
The Clavicular Branch (ramus clavicular is}, which is very small, passes upward 
to the Subclavius muscle. 
The Long Thoracic or the External Mammary (a. thoracalis lateralis} passes 
downward and inward along the lower border of the Pectoralis minor to the side 
of the chest, supplying the Serratus magnus, the Pectoral muscles, and mammary 
gland, and sending branches across the axilla to the axillary glands and Sub- 
scapularis; it anastomoses with the internal mammary and intercostal arteries. 
The Alar Thoracic is a small branch which supplies the glands and areolar 
tissue of the axilla. Its place is frequently supplied by branches from some of the 
other thoracic arteries. 
The Subscapular (a. sub scapular is}, the largest branch of the axillary artery, 
arises opposite the lower border of the Subscapularis muscle, and passes downward 
and backward along its lower margin to the inferior angle of the scapula, where it 
anastomoses with the long thoracic and intercostal arteries and with the posterior 
scapular, a branch of the transversalis colli, from the thyroid axis of the sub- 
clavian. About an inch and a half from its origin it gives off a large branch, the 
dorsalis scapulae, and terminates by supplying branches to the muscles in the 
neighborhood. 
The Dorsalis Scapulae (a. circumfexa scapuloe} is given off from the subscapular 
about an inch and a half from its origin, and is generally larger than the continua- 
tion of the vessel. It curves round the axillary border of the scapula, leaving the 
axilla through the space between the Teres minor above, the Teres major below, 
and the long head of the Triceps externally (Fig. 409), and enters the infraspinous 
fossa by passing under cover of the Teres minor, where it anastomoses with the 
posterior scapular and suprascapular arteries. In its course it gives off two sets 
of branches: one enters the subscapular fossa beneath the Subscapularis, which it 
supplies, anastomosing with the posterior scapular and suprascapular arteries; 
the other is continued along the axillary border of the scapula, between the Teres 
major and minor, and, at the dorsal surface of the inferior angle of the bone, anas- 
tomoses with the posterior scapular. In addition to these, small branches are 
distributed to the back part of the Deltoid muscle and the long head of the 
Triceps, anastomosing with an ascending branch of the superior profunda of the 
brachial. 
The Circumflex Arteries wind round the surgical neck of the humerus. The 
posterior circumflex (a. circumflexa humeri posterior} (Fig. 409), the larger of the 
two, arises from the back part of the axillary opposite the lower border of the 
Subscapularis muscle, and, passing backward with the circumflex veins and nerve 652 
THE BLOOD-VASCULAR SYSTEM 
through the quadrangular space bounded by the Teres major and minor, the 
scapular head of the Triceps and the humerus, winds round the neck of that bone 
and is distributed to the Deltoid muscle and shoulder-joint, anastomosing with the 
anterior circumflex and acromial thoracic arteries, and with the superior profunda 
branch of the brachial artery. The anterior circumflex (a. circum^exa humeri ante- 
rior) (Figs. 409 and 411), considerably smaller than the preceding, arises nearly 
opposite that vessel from the outer side of the axillary artery. It passes horizon- 
tally outward beneath the Coraco-brachialis and short head of the Biceps, lying 
upon the forepart of the neck of the 
humerus, and, on reaching the bicipital 
groove, gives off an ascending branch 
which passes upward along the groove 
to supply the head of the bone and the 
shoulder-joint. The trunk of the vessel 
is then continued outward beneath the 
Deltoid, which it supplies, and anasto- 
moses with the posterior circumflex 
artery. 
Internal 
cutaneous 
nerve. 
THE BRACHIAL ARTERY (A. BRA- 
CHIAL IS) (Fig. 412). 
Musculo- 
spiral nerve. 
The brachial artery (a. brachialis) 
commences at the lower margin of the 
tendon of the Teres major, and, passing 
down the inner and anterior aspect of 
the arm, terminates about half an inch 
below the bend of the elbow, where it 
divides into the radial and ulnar arteries. 
At first the brachial artery lies internal 
to the humerus; but as it passes down 
the arm it gradually gets in front of 
the bone, and at the bend of the elbow 
it lies midway between the two condyles. 
Relations.-This artery is superficial 
throughout its entire extent, being cov- 
ered, in front, by the integument, the 
superficial and deep fasciae; the bicipital 
fascia separates it opposite the elbow 
from the median basilic vein; the median 
nerve crosses it at its middle; behind, it 
is separated from the long head of the 
Triceps by the musculo-spiral nerve and 
superior profunda artery. It then lies 
upon the inner head of the Triceps, next 
upon the insertion of the Coraco-bra- 
chialis, and lastly on the Brachialis an- 
ticus; by its outer side, it is in relation with the commencement of the median 
nerve and the Coraco-brachialis and Biceps muscles, which overlap the artery 
to a considerable extent; by its inner side, its upper half is in relation with the 
internal cutaneous and ulnar nerves, its lower half with the median nerve. The 
basilic vein lies on the inner side of the artery, but is separated from it in the 
lower part of the arm by the deep fascia. The brachial artery is accompanied by 
Superior 
profunda. 
Inferior 
profunda. 
Anastomotica 
magna. 
Fig. 412.-The brachial artery. 'SURGICAL ANATOMY OF THE BEND OF THE ELBOW 
653 
two venae comites, which lie in close contact with the artery, being connected 
together at intervals by short transverse communicating branches. 
Plan of the Relations of the Brachial Artery 
In front. 
Integument and fasciae. 
Bicipital fascia, median basilic vein. 
Median nerve. 
Overlapped by Coraco-brachialis and Biceps. 
Outer side. 
Median nerve (above) 
Coraco-brachialis. 
Biceps. 
Brachial 
Artery. 
Inner side. 
Internal cutaneous and Ulnar nerves. 
Median nerve (below). 
Basilic vein. 
Behind. 
Triceps (long and inner heads). 
Musculo-spiral nerve. 
Superior profunda artery. 
Coraco-brachial is. 
Brachialis anticus. 
SURGICAL ANATOMY OF THE BEND OF THE ELBOW. 
At the bend of the elbow the brachial artery sinks deeply into a triangular inter- 
val, the antecubital space, the base of which is directed upward, and may be repre- 
sented by a line connecting the two condyles of the humerus; the sides are bounded, 
externally, by the inner edge of the Supinator longus; internally, by the outer mar- 
gin of the Pronator radii teres; its floor is formed by the Brachialis anticus and 
Supinator brevis. This space contains the brachial artery with its accompanying 
veins, the radial and ulnar arteries, the median and musculo-spiral nerves, and the 
tendon of the Biceps. The brachial artery occupies the middle line of this space, and 
divides opposite the neck of the radius into the radial and ulnar arteries; it is 
covered, in front, by the integument, the superficial fascia, and the median basilic 
vein, the vein being separated from direct contact with the artery by the bicipital 
fascia. Behind, it lies on the Brachialis anticus, which separates it from the 
elbow-joint. The median nerve lies on the inner side of the artery, close to it 
above, but separated from it below by the coronoid origin of the Pronator radii 
teres. The tendon of the Biceps lies to the outer side of the space, and the mus- 
culo-spiral nerve still more externally, situated upon the Supinator brevis and 
partly concealed by the Supinator longus. 
Peculiarities of the Brachial Artery as Regards its Course.-The brachial artery, accom- 
panied by the median nerve, may leave the inner border of the Biceps and descend toward the 
inner condyle of the humerus, where it usually curves round a prominence of bone, the supra- 
condylar process. From this process, in most subjects, a fibrous arch is thrown over the 
artery. The vessel then inclines outward, beneath or through the substance of the Pronator 
radii teres muscle, to the bend of the elbow. The variation bears considerable analogy to the 
normal condition of the artery in some of the carnivora: it has been referred to in the descrip- 
tion of the humerus (page 180). 
As Regards its Division.-Occasionally, the artery is divided for a short distance at its upper 
part into two trunks, which are united above and below. A similar peculiarity occurs in the main 
vessel of the lower limb. 
The point of bifurcation may be above or below the usual point, the former condition being 
by far the more frequent. Out of 481 examinations recorded by Mr. Quain, some made on the 
right and some on the left side of the body, in 386 the artery bifurcated in its normal position. 
In one case only was the place of division lower than usual, being two or three inches below the 
elbow-joint. "In 94 cases out of 481, or about 1 in 5|, there were two arteries instead of one 
in some part or in the whole of the arm." 654 
THE BLOOD-VASCULAR SYSTEM 
There appears, however, to be no correspondence between the arteries of the two arms with 
respect to their irregular division; for in 61 bodies it occurred on one side only in 43; on both 
sides, in different positions, in 13; on both sides, in the same position, in 5. 
The point of bifurcation takes place at different parts of the arm, being most frequent in 
the upper part, less so in the lower part, and least so in the middle, the most usual point for 
the application of a ligature; under any of these circumstances two large arteries would be found 
in the arm instead of one. The most frequent (in three out of four) of these peculiarities is 
the high origin of the radial. That artery often arises from the inner side of the brachial, 
and runs parallel with the main trunk to the elbow, where it crosses it, lying beneath the fascia; 
or it may perforate the fascia and pass over the artery immediately beneath the integument. 
The ulnar sometimes arises from the brachial high up, and accompanies that vessel to the 
lower part of the arm, and descends toward the inner condyle. In the forearm it generally lies 
beneath the deep fascia, superficial to the flexor muscles; occasionally between the integument 
and deep fascia, and very rarely beneath the flexor muscles. 
The interosseous artery sometimes arises from the upper part of the brachial or axillary; as 
it passes down the arm it lies behind the main trunk, and at the bend of the elbow regains its 
usual position. 
In some cases of high origin of the radial the remaining trunk (ulnar interosseous) occa- 
sionally passes, together with the median nerve, along the inner margin of the arm to the inner 
condyle, and then passing from within outward, beneath or through the Pronator radii teres, 
regains its usual position at the bend of the elbow. 
Occasionally the two arteries representing the brachial are connected at the bend of the elbow 
by a short transverse branch, and are even sometimes reunited. 
Sometimes, long slender vessels, vasa abenantia, connect the brachial or axillary arteries 
with one of the arteries of the forearm or a branch from them. These vessels usually join the 
radial. 
Varieties in Muscular Relations.1-The brachial artery is occasionally concealed in some 
part of its course by muscular or tendinous slips derived from the Coraco-brachialis, Biceps, 
Brachialis anticus, and Pronator radii teres muscles. 
Surface Marking.-The direction of the brachial artery is marked by a line drawn along 
the inner edge of the Biceps from the junction of the anterior and middle thirds of the axillary 
outlet to the middle of the front of the elbow-joint. 
Surgical Anatomy.-Compression of the brachial artery is required in cases of amputation 
and some other operations in the arm and forearm; and it will be observed that it may be effected 
in almost any part of the course of the artery. If pressure is made in the upper part of the 
limb, it should be directed from within outward; and if in the lower part, from before backward, 
as the artery lies on the inner side of the humerus above and in front of the humerus below. 
The most favorable situation is about the middle of the arm, where it lies on the tendon of the 
Coraco-brachialis on the inner flat side of the humerus. 
The application of a ligature to the brachial artery may be required in case of wound of 
the vessel and in some cases of wound of the palmar arch. It is also sometimes necessary in 
cases of aneurism of the brachial, the radial, ulnar, or interosseous arteries. The artery may 
be secured in any part of its course. The chief guides in determining its position are the sur- 
face markings produced by the inner margin of the Coraco-brachialis and Biceps, the known 
course of the vessel, and its pulsation, which should be carefully felt for before any operation is 
performed, as the vessel occasionally deviates from its usual position in the arm. In whatever 
situation the operation is performed, great care is necessary, on account of the extreme thinness 
of the parts covering the artery and the intimate connection which the vessel has throughout its 
whole course with important nerves and veins. Sometimes a thin layer of muscular fibre is 
met with concealing the artery; if such is the case, it must be cut across in order to expose the 
vessel. 
In the upper third of the arm the artery may be exposed in the following manner: The 
patient being placed supine upon a table, the affected limb should be raised from the side and 
the hand supinated. An incision about two inches in length should be made on the inner 
side of the Coraco-brachialis muscle, and the subjacent fascia cautiously divided, so as to avoid 
wounding the internal cutaneous nerve or basilic vein, which sometimes runs on the surface of 
the artery as high as the axillary. The fascia having been divided, it should be remembered that 
the ulnar and internal cutaneous nerves lie on the inner side of the artery, the median on the 
outer side, the latter nerve being occasionally superficial to the artery in this situation, and that 
the venae comites are also in relation with the vessel, one on either side. These being carefully 
separated, the aneurism needle should be passed round the artery from the inner to the outer 
side. 
If two arteries are present in the arm in consequence of a high division, they are usually 
placed side by side: and if they are exposed in an operation, the surgeon should endeavor to 
1 See Struther's Anatomical and Physiological Observations. BRANCHES OF THE BRACHIAL ARTERY 
655 
ascertain, by alternately pressing on each vessel, which of the two communicates with the wound 
or aneurism, when a ligature may be applied accordingly; or if pulsation or hemorrhage ceases 
only when both vessels are compressed, both vessels may be tied, as it may be concluded that 
the two communicate above the seat of disease or are reunited. 
It should also be remembered that two arteries may be present in the arm in a case of high 
division, and that one of these may be found along the inner intermuscular septum, in a line 
toward the inner condyle of the humerus, or in the usual position of the brachial, but deeply 
placed beneath the common trunk: a knowledge of these facts will suggest the precautions 
necessary in every case, and indicate the measures to be adopted when anomalies are met with. 
In the middle oj the arm the brachial artery may be exposed by making an incision along 
the inner margin of the Biceps muscle. The forearm being bent so as to relax the muscle, it 
should be drawn slightly aside, and, the fascia being carefully divided, the median nerve will be 
exposed lying upon the artery (sometimes beneath); this being drawn inward and the muscle 
outward, the artery should be separated from its accompanying veins and secured. In this 
situation the inferior profunda may be mistaken for the main trunk, especially if enlarged, from 
the collateral circulation having become established; this may be avoided by directing the 
incision externally toward the Biceps, rather than inward or backward toward the Triceps. 
I'he lower part oj the brachial artery is of interest in a surgical point of view, on account 
of the relation which it bears to the veins most commonly opened in venesection. Of these 
vessels, the median basilic is the largest and most prominent, and, consequently, the one usually 
selected for the operation. It should be remembered that this vein runs parallel with the 
brachial artery, from which it is separated by the bicipital fascia, and that care should be taken 
in opening the vein not to carry the incision too deeply, so as to endanger the artery. 
Collateral Circulation.-After the application of a ligature to the brachial artery in the 
upper third of the arm, the circulation is carried on by branches from the circumflex and sub- 
scapular arteries, anastomosing with ascending branches from the superior profunda. If the 
brachial is tied below the origin of the profunda arteries, the circulation is maintained by the 
branches of the profundae, anastomosing with the recurrent radial, ulnar, and interosseous 
arteries. In two cases described by Mr. South,1 in which the brachial artery had been tied some 
time previously, in one "a long portion of the artery had been obliterated, and sets of vessels 
are descending on either side from above the obliteration, to be received into others which ascend 
in a similar manner from below it. In the other the obliteration is less extensive, and a single 
curved artery about as big as a crow-quill passes from the upper to the lower open part of the 
artery." 
Branches.-The branches of the brachial artery are-the 
Superior Profunda. 
Nutrient. 
Inferior Profunda. 
Anastomotica Magna. 
Muscular. 
The Superior Profunda Artery (a. projunda brachii') arises from the inner and 
back part of the brachial, just below the lower border of the Teres major, and 
passes backward to the interval between the outer and inner heads of the Triceps 
muscle; accompanied by the musculo-spiral nerve it winds around the back part of 
the shaft of the humerus in the spiral groove, between the outer head of the Triceps 
and the bone, to the outer side of the humerus, where it reaches the external inter- 
muscular septum and divides into two terminal branches. One of these pierces 
the external intermuscular septum, and descends, in company with the musculo- 
spiral nerve, to the space between the Brachialis anticus and Supinator longus, 
where it anastomoses with the recurrent branch of the radial artery; while the 
other, much the larger of the two, descends along the back of the external inter- 
muscular septum to the back of the elbow-joint, where it anastomoses with the 
posterior interosseous recurrent, and across the back of the humerus with the pos- 
terior ulnar recurrent, the anastomotica magna, and inferior profunda (Fig. 415). 
The superior profunda supplies the Triceps muscle and gives off a nutrient artery 
which enters the bone at the upper end of the musculo-spiral groove. Near its 
commencement it sends off a branch which passes upward between the external 
and long heads of the Triceps muscle to anastomose with the posterior circumflex 
1 Chelius's Surgery, vol. ii. p. 254. See also White's engravings, referred to by Mr. South, of the anastomos- 
ing branches after ligature of the brachial, in White's Cases in Surgery. Porta also gives a case (with drawings) 
of the circulation after ligature of both brachial and radial (Alterazioni Patoligiche delle Arterie).-Ed. of 15th 
English edition. THE BLOOD-VASCULAR SYSTEM 
656 
artery, and, while in the groove, a small branch which accompanies a branch of 
the musculo-spiral nerve through the substance of the Triceps muscle and ends 
in the Anconeus below the outer 
condyle of the humerus. 
The Nutrient Artery (a. nutricia 
humeri) of the shaft of the humerus 
arises from the brachial, about the 
middle of the arm. Passing down- 
ward it enters the nutrient canal of 
that bone near the insertion of the 
Coraco-brachialis muscle. 
The Inferior Profunda (a. col- 
lateralis ulnaris superior), of small 
size, arises from the brachial, a little 
below the middle of the arm; pierc- 
ing the internal intermuscular sep- 
tum, it descends on the surface of 
the inner head of the Triceps mus- 
cle to the space between the inner 
condyle and olecranon, accompanied 
by the ulnar nerve, and terminates 
by anastomosing with the posterior 
ulnar recurrent and anastomotica 
magna. It sometimes supplies a 
branch to the front of the internal 
condyle, which anastomoses with 
the anterior ulnar recurrent. 
The Anastomotica Magna (a. 
collateralis ulnaris inferior) arises 
from the brachial about two inches 
above the elbow-joint. It passes 
transversely inward upon the Bra- 
chialis anticus, and, piercing the 
internal intermuscular septum,winds 
round the back of the humerus be- 
tween the Triceps and the bone, 
forming an arch above the olecranon 
fossa by its junction with the poste- 
rior articular branch of the superior 
profunda. As this vessel lies on the 
Brachialis anticus, branches ascend 
to join the inferior profunda, and 
others descend in front of the inner 
condyle to anastomose with the an- 
terior ulnar recurrent. Behind the 
internal condyle an offset is given 
off which anastomoses with the infe- 
rior profunda and posterior ulnar 
recurrent arteries and supplies the 
Triceps. 
The Muscular (rami musculares) 
are three or four large branches, 
which are distributed to the muscles in the course of the artery. They supply 
the Coraco-brachialis, Biceps, and Brachialis anticus muscles. 
Radial recurrent.' 
Deep branch 
of ulnar. 
Superficialis volx.- 
Fig. 413.-The radial and ulnar arteries. THE RADIAL ARTERY 
657 
The Anastomosis around the Elbow-joint (Fig. 415).-The vessels engaged 
in this anastomosis may be conveniently divided into those situated in front and 
behind the internal and external condyles. The branches anastomosing in front 
of the internal condyle are the anastomotica magna, the anterior ulnar recurrent, 
and the anterior terminal branch of the inferior profunda. Those behind the in- 
ternal condyle are the anastomotica magna, the posterior ulnar recurrent, and the 
posterior terminal branch of the inferior profunda. The branches anastomosing 
in front of the external condyle are the radial recurrent and the anterior terminal 
branch of the superior profunda. Those behind the external condyle (perhaps 
more properly described as being situated between the external condyle and the 
olecranon) are the anastomoticamagna, the interosseous recurrent, and the posterior 
terminal branch of the superior profunda. There is also a large arch of anasto- 
mosis above the olecranon, formed by the interosseous recurrent, joining with the 
anastomotica magna and posterior ulnar recurrent. 
From this description it will be observed that the anastomotica magna is the 
vessel most engaged, the only part of the anastomosis in which it is not employed 
being that in front of the external condyle. 
The Radial Artery (A. Radialis) (Figs. 413, 414). 
The radial artery appears, from its direction, to be the continuation of the 
brachial, but in size it is smaller than the ulnar. It commences at the bifurcation of 
the brachial, just below the bend of the elbow, and passes alongthe radial side of the 
forearm to the wrist; it then winds backward, round the outer side of the carpus, 
beneath the extensor tendons of the thumb, to the upper end of the space between 
the metacarpal bones of the thumb and index finger, and finally passes forward, 
between the two heads of the First dorsal interosseous muscle, into the palm of the 
hand, where it crosses the metacarpal bones to the ulnar border of the hand, to form 
the deep palmar arch. At its termination it inosculates with the deep branch of the 
ulnar artery. The relations of this vessel may thus be conveniently divided into 
three parts-viz., in the forearm, at the back of the wrist, and in the hand. 
Relations.-In the forearm this vessel extends from opposite the neck of the 
radius to the forepart of the styloid process, being placed to the inner side of the 
shaft of the bone above and in front of it below. It is overlapped in the upper 
part of its course by the fleshy belly of the Supinator longus muscle; throughout 
the rest of its course it is superficial, being covered by the integument, the super- 
ficial and deep fasciae. In its course downward it lies upon the tendon of the 
Biceps, the Supinator brevis, the Pronator radii teres, the radial origin of the 
Flexor sublimis digitorum, the Flexor longus pollicis, the Pronator quadratus, and 
the lower extremity of the radius. In the upper third of its course it lies between 
the Supinator longus and the Pronator radii teres; in the lower two-thirds, between 
the tendons of the Supinator longus and the Flexor carpi radialis. The radial 
nerve lies close to the outer side of the artery in the middle third of its course, 
and some filaments of the musculo-cutaneous nerve, after piercing the deep fascia, 
run along the lower part of the artery as it winds round the wrist. The vessel is 
accompanied by venre comites throughout its whole course. 
Plan of the Relations of the Radial Artery in the Forearm. 
In front. 
Skin, superficial and deep fasciae. 
Supinator longus. 
Inner side. 
Pronator radii teres. 
Flexor carpi radialis. 
Radial 
Artery in 
Forearm. 
Outer side. 
Supinator longus. 
Radial nerve (middle third). 658 
THE BLOOD-VASCULAR SYSTEM 
Behind. 
Tendon of Biceps. 
Supinator brevis. 
Pronator radii teres. 
Flexor sublimis digitorum. 
Flexor longus pollicis. 
Pronator quadratus. 
Radius. _ 
At the wrist, as it winds round the outer side of the carpus from the styloid 
process to the first interosseous space, it lies upon the external lateral ligament, 
and then upon the scaphoid bone and trapezium, being covered by the extensor 
tendons of the thumb, subcutaneous veins, some filaments of the radial nerve, and 
the integument. It is accompanied by two veins and a filament of the musculo- 
cutaneous nerve. 
In the hand it passes from the upper end of the first interosseous space, 
between the heads of the Abductor indicis or First dorsal interosseous muscle, 
transversely across the palm, to the base of the metacarpal bone of the little 
finger, where it inosculates with the communicating branch from the ulnar artery, 
forming the deep palmar arch. 
The Deep Palmar Arch {arcus volaris profundus) (Fig. 414).-It lies upon the 
carpal extremities of the metacarpal bones and the Interossei muscles, being 
covered by the Adductor obliquus pollicis, the flexor tendons of the fingers, the 
Lumbricales, the Opponens, and Flexor brevis minimi digiti. Alongside of it is 
the deep branch of the ulnar nerve, but running in the opposite direction; that 
is to say, from within outward. The branches of the deep palmar arch are the 
palmar interosseous, perforating and palmar recurrent vessels (page 660). 
Peculiarities.-The origin of the radial artery, according to Quain, is, in nearly one case 
in eight, higher than usual; more frequently arising from the axillary or upper part of the brachial 
than from the lower part of this vessel. The variations in the position of this vessel in the arm 
and at the bend of the elbow have been already mentioned. In the forearm it deviates less fre- 
quently from its position than the ulnar. It has been found lying over the fascia instead of 
beneath it. It has also been observed on the surface of the Supinator longus, instead of under 
its inner border; and in turning round the wrist it has been seen lying over, instead of beneath, 
the extensor tendons of the thumb. 
Surface Marking.-The position of the radial artery in the forearm is represented by a line 
drawn from the outer border of the tendon of the Biceps in the centre of the hollow in front 
of the elbow-joint with a straight course to the inner side of the forepart of the styloid process 
of the radius. 
Surgical Anatomy.-The radial artery is much exposed to injury in its lower third, and is 
frequently wounded by the hand being driven through a pane of glass, by the slipping of a 
knife or chisel held in the other hand, and similar accidents. The injury is often followed by 
a traumatic aneurism, for which the operation of extirpating or laying open the sac after securing 
the vessel above and below is required. 
The operation of tying the radial artery is required in cases of wounds either of its trunk or 
of some of its branches, or for aneurism; and it will be observed that the vessel may be exposed 
in any part of its course through the forearm without the division of any muscular fibres. The 
operation in the middle or inferior third of the forearm is easily performed, but in the upper 
third, near the elbow, it is attended with some difficulty, from the greater depth of the vessel 
and from its being overlapped by the Supinator longus muscle. 
To tie the artery in the upper third an incision three inches in length should be made through 
the integument, in a line drawn from the centre of the bend of the elbow to the front of the 
styloid process of the radius, avoiding the branches of the median vein; the fascia of the arm 
being divided and the Supinator longus drawn a little outward, the artery will be exposed. The 
venae comites should be carefully separated from the vessel, and the ligature passed from the 
radial to the ulnar side. 
In the middle third of the forearm the artery may be exposed by making an incision of similar 
length on the inner margin of the Supinator longus. In this situation the radial nerve lies in close 
relation with the outer side of the artery, and should, as well as the veins, be carefully avoided. 
In the lower third the artery is easily secured by dividing the integument and fascia in the 
interval between the tendons of the Supinator longus and Flexor carpi radialis muscles. THE RADIAL ARTERY 
659 
Branches (Figs. 413, 414, and 415).-The branches of the radial artery may 
be divided into three groups, corresponding with the three regions in which the 
vessel is situated. 
Radial Recurrent. 
Muscular. 
Anterior Radial Carpal. 
Superficialis Voise. 
Posterior Radial Carpal. 
Metacarpal. 
Dorsales Pollicis. 
Dorsalis Indicis. 
In the 
Forearm 
Wrist 
Princeps Pollicis. 
Radialis Indicis. 
Perforating. 
Palmar Interosseous. 
Palmar Recurrent. 
Hand 
The Radial Recurrent (a. recurrens radialis) (Fig. 414) is given off imme- 
diately below the elbow. It ascends between the branches of the musculo-spiral 
nerve lying on the Supinator brevis, and then between the Supinator longus and 
Brachialis anticus, supplying these muscles and the elbow-joint, and anastomosing 
with the terminal branches of the superior profunda. 
The Muscular Branches (rami musculares) are distributed to the muscles on 
the radial side of the forearm. 
The Anterior Radial Carpal (ramus carpeus volaris) (Fig. 414) is a small 
vessel which arises from the radial artery near the lower border of the Pronator 
quadratus, and, running inward in front of the radius, anastomoses with the ante- 
rior carpal branch of the ulnar artery. In this way an arterial anastomosis, the 
anterior carpal arch (rete carpi volare), is formed in front of the wrist; it is joined 
by branches from the anterior interosseous above, and by recurrent branches from 
the deep palmar arch below, and gives off branches which descend to supply the 
articulations of the wrist and carpus. 
The Superficialis Volae (ramus volaris superficialis) (Fig. 414) arises from the 
radial artery, just where this vessel is about to wind round the wrist. Running 
forward, it passes between, occasionally over, the muscles of the thumb, which it 
supplies, and sometimes anastomoses with the palmar portion of the ulnar artery, 
completing the superficial palmar arch. This vessel varies considerably in size: 
usually it is very small, and terminates in the muscles of the thumb; sometimes 
it is as large as the continuation of the radial. 
The Posterior Radial Carpal (ramus carpeus dorsalis) (Fig. 415) is a small 
vessel which arises from the radial artery beneath the extensor tendons of the 
thumb; crossing the carpus transversely to the inner border of the hand, it 
anastomoses with the posterior carpal branch of the ulnar, forming the posterior 
carpal arch (rete carpi dorsale), which is joined by the termination of the anterior 
interosseous artery. From this arch are given off descending branches, the 
dorsal interosseous arteries (aa. metacarpece dorsales) for the second, third, and 
fourth interosseous spaces, which run forward on the Second, Third, and 
Fourth dorsal interossei muscles, and divide into dorsal digital branches (aa. 
digitales dorsales), which supply the adjacent sides of the index, middle, ring, 
and little fingers respectively, communicating with the digital arteries of the 
superficial palmar arch. The dorsal interosseous arteries anastomose with the 
perforating branches from the deep palmar arch (rami perj or antes). 
The Dorsales Pollicis (Fig. 415) are two vessels which run along the sides of 
the dorsal aspect of the thumb. They arise separately, or occasionally by a 
common trunk, near the base of the first metacarpal bone. 
The Dorsalis Indicis (Fig. 415), also a small branch, runs along the radial side 
of the back of the index finger, sending a few branches to the Abductor indicis. 660 
THE BLOOD-VASCULAR SYSTEM 
The Princeps Pollicis (a. princeps pollicis) (Fig. 41A)arises from the radial just as 
it turns inward to the deep part of the hand; it descends between the Abductor indicis 
and Adductor obliquu pollicis, then 
between the Adductor transversus 
pollicis and Adductor obliquus 
pollicis, along the ulnar side of the 
metacarpal bone of the thumb, to 
the base of the first phalanx, where 
it divides into two branches, which 
run along the sides of the palmar 
aspect of the thumb, and form an 
arch on the palmar surface of the 
last phalanx, from which branches 
are distributed to the integument 
and pulp of the thumb. 
The Radialis Indicis (a. volaris 
indicis radialis) (Fig. 414) arises 
close to the preceding, descends 
between the Abductor indicis and 
Adductor transversus pollicis, and 
runs along the radial side of the 
index finger to its extremity, where 
it anastomoses with the collateral 
digital artery from the superficial 
palmar arch. At the lower border 
of the Adductor transversus pollicis 
this vessel anastomoses with the 
princeps pollicis, and gives a com- 
municating branch to the super- 
ficial palmar arch. 
The Perforating Arteries (rami 
perforates) (Fig. 414), three in 
number, pass backward from the 
deep palmar arch between the 
heads of the last three Dorsal inter- 
ossei muscles, to inosculate with 
the dorsal interosseous arteries. 
The Palmar Interosseous (aa. 
metacarpeoe volares)(Fig. 414), three 
or four in number, arise from the 
convexity of the deep palmar arch; 
they run forward upon the Inter- 
ossei muscles,and anastomose at the 
clefts of the fingers with the digital 
branches of the superficial arch. 
The Palmar Recurrent Branches arise from the concavity of the deep palmar 
arch. They pass upward in front of the wrist, supplying the carpal articulations 
and anastomosing with the anterior carpal arch. 
Anastomotica 
magna. 
Radial 
recurrent. 
Anterior ulnar 
recurrent. 
Posterior ulnar 
recurrent. 
Posterior 
interosseous. 
Muscular.. 
Muscular. 
Anterior carpal. 
Superficialis volse. 
■Anterior carpal 
Deep branch of 
ulnar. 
Fig. 414.-Ulnar and radial arteries. Deep view. 
The Ulnar Artery (A. Ulnaris) (Figs. 413, 414). 
The ulnar artery, the larger of the two terminal branches of the brachial, 
commences a little below the bend of the elbow, and crosses obliquely the THE ULNAR ARTERY 
661 
inner side of the forearm to the commencement of its lower half; it then 
runs along its ulnar border to the wrist, crosses the annular ligament on the 
radial side of the pisiform bone, and immediately beyond this bone divides into 
two branches which enter into the formation of the superficial and deep palmar 
arches. 
Relations. In the Forearm.-In its upper half it is deeply seated, being cov- 
ered by all the superficial Flexor muscles, excepting the Flexor carpi ulnaris; the 
median nerve is in relation with the inner side of the artery for about an inch and 
then crosses the vessel, being separated from it by the deep head of the Pronator 
radii teres; it lies upon the Brachialis anticus and Flexor profundus digitorum 
muscles. In the lower half of the forearm it lies upon the Flexor profundus, being 
covered by the integument, the superficial and deep fasciae, and is placed between 
the Flexor carpi ulnaris and Flexor sublimis digitorum muscles. It is accompanied 
by two venae comites; the ulnar nerve lies on its inner side for the lower two- 
thirds of its extent, and a small branch from the nerve descends on the lower part 
of the vessel to the palm of the hand. 
Plan of Relations of the Ulnar Artery in the Forearm. 
In front. 
Superficial layer of flexor muscles. 1 TT , 
•]\t i* * I Upper halt. 
Median nerve. ) 
Superficial and deep fasciae. Lower half. 
Inner side. 
Flexor carpi ulnaris. 
Ulnar nerve (lower two-thirds). 
Ulnar 
Artery in 
Forearm. 
Outer side. 
Flexor sublimis digitorum. 
Behind. 
Brachialis anticus. 
Flexor profundus digitorum. 
At the wrist (Fig. 413) the ulnar artery is covered by the integument and fascia, 
and lies upon the anterior annular ligament. On its inner side is the pisiform bone. 
The ulnar nerve lies at the inner side, and somewhat behind the artery; here the 
nerve and artery are crossed by a band of fibres, which extends from the pisiform 
bone to the anterior annular ligament. 
Peculiarities.-The ulnar artery has been found to vary in its origin nearly in the propor- 
tion of one in thirteen cases, in one case arising lower than usual, about two or three inches 
below the elbow, and in all other cases much higher, the brachial being a more frequent source 
or origin than the axillary. 
Variations in the position of this vessel are more frequent than in the radial. When its origin 
is normal the course of the vessel is rarely changed. When it arises high up it is almost invaria- 
bly superficial to the Flexor muscles in the forearm, lying commonly beneath the fascia, more 
rarely between the fascia and integument. In a few cases its position was subcutaneous in the 
upper part of the forearm, subaponeurotic in the lower part. 
Surface Marking.-On account of the curved direction of the ulnar artery the line on the 
surface of the body which indicates its course is somewhat complicated. First, draw a line from 
the front of the internal condyle of the humerus to the radial side of the pisiform bone; the 
lower two-thirds of this line represents the course of the middle and lower third of the ulnar 
artery. Secondly, draw' a line from the centre of the antecubital space to the junction of the 
upper and middle third of the first line; this represents the course of the upper third of the 
artery. 
Surgical Anatomy.-The application of a ligature to this vessel is required in cases of wound 
of the artery or of its branches, or in consequence of aneurism. In the upper hall of the fore- 
arm the artery is deeply seated beneath the superficial flexor muscles, and the application of a 
ligature in this situation is attended with some difficulty. An incision is to be made in the 
course of a line drawn from the front of the internal condyle of the humerus to the outer side 662 
THE BLOOD VASCULAR SYSTEM 
of the pisiform bone, so that the centre of the incision is three fingers' breadth below the internal 
condyle. The skin and superficial fascia having been divided and the deep fascia exposed, 
the white line which separates the Flexor carpi ulnaris from the other flexor muscles is to be 
sought for, and the fascia incised in this line. The Flexor carpi ulnaris is now to be carefully 
separated from the other muscles, when the ulnar nerve will be exposed, and must be drawn 
aside. Some little distance below the nerve the artery will be found accompanied by its venae 
comites, and it may be ligatured by passing the needle from within outward. In the middle and 
lower third of the forearm this vessel may be easily secured by making an incision on the radial 
side of the tendon of the Flexor carpi ulnaris: the deep fascia being divided, and the Flexor 
carpi ulnaris and its companion muscle, the Flexor sublimis, being separated from each other, 
the vessel will be exposed, accompanied by its venae comites, the ulnar nerve lying on its inner 
side. The veins being separated from the artery, the ligature should be passed from the ulnar 
to the radial side, taking care to avoid the ulnar nerve. 
Branches (Figs. 413, 414, and 415).-The branches of the ulnar artery may 
be arranged in the following groups: 
Anterior Ulnar Recurrent. 
Posterior Ulnar Recurrent. 
Forearm 
Anterior Interosseous. 
Posterior Interosseous. 
Interosseous 
Muscular. 
Anterior Carpal. 
Posterior Carpal. 
Wrist 
Deep Palmar or Communicating. 
Superficial Palmar Arch. 
Hand 
The Anterior Ulnar Recurrent (a. recurrentes ulnaris anterior) (Fig. 414) 
arises immediately below the elbow-joint, passes upward and inward between the 
Brachialis anticus and Pronator radii teres, supplies twigs to those muscles, and, 
in front, of the inner condyle anastomoses with the anastomotica magna and 
inferior profunda. 
The Posterior Ulnar Recurrent (a. recurrentes ulnaris posterior) (Figs. 414 and 
415) is much larger, and arises somewhat lower than the preceding. It passes 
backward and inward, beneath the Flexor sublimis, and ascends behind the inner 
condyle of the humerus. In the interval between this process and the olecranon 
it lies beneath the Flexor carpi ulnaris, and ascending between the heads of that 
muscle, in relation with the ulnar nerve; it supplies the neighboring muscles and 
joint, and anastomoses with the inferior profunda, anastomotica magna, and 
interosseous recurrent arteries. 
The Interosseous Artery (a. interossea communis) (Fig. 414) is a short trunk 
about half an inch in length, and of considerable size, which arises immediately, 
below the tuberosity of the radius, and, passing backward to the upper border of 
the interosseous membrane, divides into two branches, the anterior and posterior 
interosseous. 
The Anterior Interosseous (a. interossea volaris) (Fig. 414) passes down the fore- 
arm on the anterior surface of the interosseous membrane, to which it is connected 
by a thin aponeurotic arch. It is accompanied by the interosseous branch of the 
median nerve, and overlapped by the contiguous margins of the Flexor profundus 
digitorum and Flexor longus pollicis muscles, giving off in this situation muscular 
branches and the nutrient arteries of the radius and ulna. At the upper border 
of the Pronator quadratus a branch, anterior communicating artery, descends 
beneath the muscle to anastomose in front of the carpus with the anterior carpal 
arch. The continuation of the artery passes behind the Pronator quadratus, and, 
piercing the interosseous membrane, reaches the back of the forearm, and anasto- 
moses with the posterior interosseous artery (Fig. 415). It then descends to the 
back of the wrist to join the posterior carpal arch. The anterior interosseous gives THE ULNAR ARTERY 
663 
off a long, slender branch, the median artery or artery comes nervi mediana 
(a. mediana), which accompanies the median nerve and gives offsets to its sub- 
stance. This artery is some- 
times much enlarged, and ac- 
companies the nerve into the 
palm of the hand. 
The Posterior Interosseous 
Artery (a. interossea dorsalis) 
(Figs. 414 and 415) passes 
backward through the inter- 
val between the oblique liga- 
ment and the upper border of 
the interosseous membrane. 
It appears between the con- 
tiguous borders of the Supina- 
tor brevis and the Extensor 
ossis metacarpi pollicis, and 
runs down the back part of 
the forearm, between the su- 
perficial and deep layer of 
muscles, to both of which it 
distributes branches. At the 
lower part of the forearm it 
anastomoses with the termina- 
tion of the anterior interosse- 
ous artery. Then, continuing 
its course over the head of 
the ulna, it joins the posterior 
carpal branch of the ulnar 
artery. This artery gives off, 
near its origin, the interosseous 
recurrent branch. 
The interosseous recurrent 
artery (a. interossea recurrens) 
(Fig.415)is a large vessel which 
ascends to the interval between 
the external condyle and olec- 
ranon, on or through the fibres 
of the Supinator brevis, but 
beneath the Anconeus, anas- 
tomosing with a branch from 
the superior profunda, and 
with the posterior ulnar recur- 
rent and anastomotica magna. 
The Muscular Branches 
(rami musculares) are distri- 
buted to the muscles along 
the ulnar side of the forearm. 
The Anterior Carpal (ramus carpeus volaris) (Fig. 414) is a small vessel 
which crosses the front of the carpus beneath the tendons of the Flexor pro- 
fundus, and inosculates with a corresponding branch of the radial artery. 
The Posterior Carpal (ramus carpeus dorsalis) (Fig. 415) arises immediately 
above the pisiform bone, and winds backward beneath the tendon of the Flexor 
carpi ulnaris: it passes across the dorsal surface of the carpus beneath the extensor 
Descending branch from 
superior profunda. 
Anastomotica. 
magna. 
Posterior ulnar 
recurrent. 
■Posterior interosseous. 
Termination of an- 
terior interosseous. 
Posterior carpal 
(ulnar). 
Posterior carpal 
(radial). 
■Radial. 
.Dorsalis pollicis. 
-Dorsalis indicis. 
Fig. 415.-Arteries of the back of the forearm and.hand. THE BLOOD-VASCULAR SYSTEM 
664 
tendons, anastomosing with a corresponding branch of the radial artery, and 
forming the posterior carpal arch (rete carpi dorsale) (Fig. 415). Immediately after 
its origin it gives off a small branch which runs along the ulnar side of the meta- 
carpal bone of the little finger, forming one of the metacarpal arteries, and supplies 
the ulnar side of the dorsal surface of the little finger. 
The Deep or Communicating Branch to the Deep Palmar Arch (ramus 
volaris profundus) (Fig. 414) passes deeply inward between the Abductor minimi 
digiti and Flexor brevis minimi digiti, near their origins; it anastomoses with the 
termination of the radial artery, completing the deep palmar arch. 
The continuation of the trunk of the ulnar artery in the hand forms the greater 
part of the superficial palmar arch. 
The Superficial Palmar Arch (arcus volaris superficialis) (Fig. 413) is formed 
by the ulnar artery in the hand, and is completed on the outer side by this vessel 
anastomosing with a branch from the radialis indicis, though sometimes the arch 
is completed by the ulnar anastomosing with the superficialis vohe or the princeps 
pollicis of the radial artery. The arch passes across the palm, describing a curve, 
with its convexity forward, to the space between the ball of the thumb and the 
index finger, where the above-mentioned anastomosis takes place. 
Relations.-The superficial palmar arch is covered by the skin, the Palmaris 
brevis, and the palmar fascia. It lies upon the annular ligament, the Flexor 
brevis of the little finger, the tendons of the superficial flexor of the fingers, and 
the divisions of the median and ulnar nerves. 
Plan of the Relations of the Superficial Palmar Arch. 
In front. 
Skin. 
Palmaris brevis. 
Palmar fascia. 
Superficial 
Palmar 
Arch. 
Behind. 
Annular ligament. 
Flexor brevis of little finger. 
Superficial flexor tendons. 
Divisions of median and ulnar nerves. 
Branches.-The branches of the Superficial Palmar Arch are the 
Digital. 
The Digital Branches (aa. digitales volares communes) (Fig. 413), four in number, 
are given off from the convexity of the superficial palmar arch. They supply the 
ulnar side of the little finger and the adjoining sides of the little, ring, middle, and 
index fingers, the radial side of the index finger and thumb being supplied from 
the radial artery. The digital arteries at first lie superficial to the flexor tendons, 
but as they pass forward with the digital nerves to the clefts between the fingers 
they lie between them, and are there joined by the interosseous branches from the 
deep palmar arch. The digital arteries on the sides of the fingers lie beneath the 
digital nerves; and about the middle of the last phalanx the two branches for each 
finger form an arch, from the convexity of which branches pass to supply the 
pulp of the finger. THE THORACIC AORTA 
665 
Surface Marking.-The superficial palmar arch is represented by a curved line, starting 
from the outer side of the pisiform bone and carried downward as far as the middle third of 
the palm, and then curved outward on a level with the upper end of the cleft between the thumb 
and index finger. The deep palmar arch is situated about half an inch nearer to the carpus. 
Surgical Anatomy.-Wounds of the palmar arches are of special interest, and are always 
difficult to deal with. When the superficial arch is wounded it is generally possible, by enlarging 
the wound if necessary, to secure the vessel and tie it; or in cases where it is found impossible to 
encircle the vessel with a ligature, a pair of haemostatic forceps may be applied and left on for 
twenty-four or forty-eight hours. Wounds of the deep arch are not so easily dealt with. It may 
be possible to secure the vessel by ligature or by forcipressure forceps, which may be left on; 
or, failing in this, the wound may be carefully plugged with gauze and an outside dressing care- 
fully bandaged on. The plug should be allowed to remain untouched for three or four days. 
In wounds of the deep palmar arch a ligature may be applied to the bleeding points from the 
dorsum of the hand by resection of the upper part of the third metacarpal bone. It is useless 
in these cases to ligate one of the arteries of the forearm alone, and indeed simultaneous liga- 
tion of both radial and ulnar arteries above the wrist is often unsuccessful, on account of the 
anastomosis carried on by the carpal arches. Therefore, if unable to ligate the divided ends 
of the arch, upon the failure of pressure to arrest hemorrhage, it is expedient to apply a ligature 
to the brachial artery. 
ARTERIES OF THE TRUNK 
THE DESCENDING AORTA (Figs. 416, 417). 
The descending aorta is divided into two portions, the thoracic and abdominal, 
in correspondence with the two great cavities of the trunk in which it is situated. 
The Thoracic Aorta (Aorta Thoracalis) (Fig. 416). 
The thoracic aorta commences at the lower border of the fourth dorsal 
vertebra, on the left side, and terminates at the aortic opening in the Diaphragm, 
in front of the lower border of the last dorsal vertebra. At its commencement it 
is situated on the left side of the spine; it approaches the median line as it 
descends, and at its termination lies directly in front of the spinal column. The 
direction of this vessel being influenced by the spine, upon which it rests, it 
describes a curve which is concave forward in the dorsal region. As the branches 
given off from it are small, the diminution in the size of the vessel is inconsider- 
able. It is contained in the back part of the posterior mediastinum. 
Relations.-It is in relation, in front, from above downward, with the root of 
the left lung, the pericardium, the oesophagus, and the Diaphragm: behind, with 
the vertebral column and the vense azygos minor; on the right side, with the vena 
azygos major and thoracic duct; on the left side, with the left pleura and lung. 
The oesophagus, with its accompanying nerves, lies on the right side of the aorta 
above; but at the lower part of the thorax it gets in front of the aorta, and close 
to the Diaphragm is situated to its left side. 
Plan of the Relations of the Thoracic Aorta. 
In front. 
Root of left lung. 
Pericardium. 
(Esophagus. 
Diaphragm. 
Right side. 
(Esophagus (above). 
Vena azygos major. 
Thoracic duct. 
Left side. 
Pleura. 
Left lung. 
(Esophagus (below). 
Thoracic 
Aorta. 
Behind. 
Vertebral column. 
Superior and inferior azygos minor veins. 666 
THE BLOOD-VASCULAR SYSTEM 
The aorta is occasionally found to be obliterated at a particular spot-viz., at the junction of 
the arch with the thoracic aorta just below the ductus arteriosus. Whether this is the result of 
disease or of congenital malformation is immaterial to our present purpose; it affords an interest- 
ing opportunity of observing the resources of the collateral circulation. The course of the anas- 
tomosing vessels, by which the blood is brought from the upper to the lower part of the artery, 
will be found well described in an account of two cases in the Pathological Transactions, vols. viii. 
and x. In the former (p. 162) Mr. Sydney Jones thus sums up the detailed description of the 
anastomosing vessels: "The principal communications by which the circulation was carried on, 
were--Firstly, the internal mammary, anastomosing with the intercostal arteries, with the phrenic 
of the abdominal aorta by means of the musculo-phrenic and comes nervi phrenici, and largely 
with the deep epigastric. Secondly, the superior intercostal, anastomosing anteriorly by means 
of a large branch with the first aortic intercostal, and posteriorly with the posterior branch of the 
same artery. Thirdly, the inferior thyroid, by means of a branch about the size of an ordinary 
radial, formed a communication with the first aortic intercostal. Fourthly, the transversalis colli, 
by means of very large communications with the posterior branches of the intercostals. Fifthly, 
the branches (of the subclavian and axillary) going to the side of the chest were large, and anas- 
tomosed freely with the lateral branches of the intercostals." In the second case also (vol. x. 
p. 97) Mr. Wood describes the anastomoses in a somewhat similar manner, adding the remark 
that "the blood which was brought into the aorta through the anastomoses of the intercostal 
arteries appeared to be expended principally in supplying the abdomen and pelvis, while the 
supply to the lower extremities had passed through the internal mammary and epigastrics." 
Surgical Anatomy.-The student should now consider the effects likely to be produced by 
aneurism of the thoracic aorta, a disease of common occurrence. When we consider the great 
depth of the vessel from the surface and the number of important structures which surround it 
on every side, it may easily be conceived what a variety of obscure symptoms may arise from dis- 
ease of this part of the arterial system, and how they may be liable to be mistaken for those of 
other affections. Aneurism of the thoracic aorta most usually extends backward along the left 
side of the spine, producing absorption of the bodies of the vertebrae, with curvature of the spine; 
whilst the irritation or pressure on the cord will give rise to pain, either in the chest, back, or 
loins, with radiating pain in the left upper intercostal spaces, from pressure on the intercostal 
nerves; at the same time the tumor may project backward on each side of the spine, beneath the 
integument, as a pulsating swelling, simulating abscess connected with diseased bone, or it may 
displace the oesophagus and compress the lung on one or the other side. If the tumor extend 
forward, it may press upon and displace the heart, giving rise to palpitation and other symptoms 
of disease of that organ; or it may displace, or even compress, the oesophagus, causing pain and 
difficulty of swallowing, as in stricture of that tube; and ultimately even open into it by ulcera- 
tion, producing fatal hemorrhage. If the disease extends to the right side, it may press upon 
the thoracic duct; or it may burst into the pleural cavity or into the trachea or lung; and, lastly, 
it may open into the posterior mediastinum. 
Branches.-Branches of the thoracic aorta supply the thoracic viscera. 
They are known as rami viscerales. 'The rami viscerales are the bronchial, oesoph- 
ageal, pericardial, and mediastinal arteries. Other branches of the thoracic aorta 
supply the walls of the chest. They are known as rami parietales or intercostal arteries. 
The Bronchial Arteries (aa. bronchioles) are the nutrient vessels of the lungs, 
and vary in number, size, and origin. That of the right side arises from the first 
aortic intercostal, or by a common trunk with the left bronchial from the front of 
the thoracic aorta. Those of the left side, usually two in number, arise from the 
thoracic aorta, one a little lower than the other. Each vessel is directed to the 
back part of the corresponding bronchus along which it runs, dividing and sub- 
dividing along the bronchial tube, supplying them, the cellular tissue of the lungs, 
the bronchial glands, and the oesophagus. 
The (Esophageal Arteries (aa. oesophagece), usually four or five in number, 
arise from the front of the aorta, and pass obliquely downward to the oesophagus, 
forming a chain of anastomoses along that tube, anastomosing with the oesoph- 
ageal branches of the inferior thyroid arteries above, and with ascending branches 
from the phrenic and gastric arteries below. 
The Pericardiac (rami pericardiaci) are a few small vessels, irregular in their 
origin, distributed to the pericardium. 
rhe Posterior Mediastinal Arteries (rami mediastinales) are numerous 
small vessels which supply the glands and loose areolar tissue in the mediastinum. THE THORACIC AORTA 
667 
The lower mediastinal branches are known as the superior phrenic arteries (an. 
phrenicce superior es), and are distributed to the posterior portion of the Diaphragm. 
The Intercostal Arteries (aa. inter cost ales) (Fig. 416) arise from the back of the 
aorta. The aortic intercostals are usually nine in number on each side, the two 
superior intercostal spaces being supplied 
by the superior intercostal, a branch of the 
subclavian. The second space usually 
receives a considerable branch from the 
first aortic intercostal, which joins with 
the branch from the superior intercostal 
of the subclavian. The branch which runs 
along the lower border of the last rib is 
named the subcostal artery. The right 
intercostals are longer than the left, on 
account of the position of the aorta on the 
left side of the spine: they pass outward, 
across the bodies of the vertebra?, to the 
intercostal spaces, being covered by the 
pleura, the (esophagus, thoracic duct, 
sympathetic nerve, and the vena azygos 
major; the left, passing outward, are 
crossed by the sympathetic; the upper two 
are also crossed by the superior inter- 
costal vein, the lower by the azygos minor 
veins. In each intercostal space the artery 
passes outward, the External intercostal 
muscle being behind, the pleura and a thin 
fascia being in front. It then passes be- 
tween the two layers of Intercostal mus- 
cles, and, having ascended obliquely to 
the lower border of the rib above it, is 
continued forward in the groove on its 
lower border and anastomoses with the 
anterior intercostal branches of the in- 
ternal mammary. The first aortic inter- 
costal anastomoses with the superior in- 
tercostal branch of the subclavian, and 
the last three intercostals pass between 
the abdominal muscles, inosculating with the epigastric in front and with the 
phrenic and lumbar arteries. Each intercostal artery is accompanied by a vein and 
nerve, the former being above, and the latter below, except in the upper inter- 
costal spaces, where the nerve is at first above the artery. The arteries are pro- 
tected from pressure during the action of the Intercostal muscles by fibrous arches 
thrown across, and attached by each extremity to the bone. The lower intercostal 
arteries are continued anteriorly from the intercostal spaces into the abdominal 
wall, except the subcostal, which lies throughout its whole course in the abdominal 
wall, since it is placed below the last rib. They pass behind the costal cartilages 
between the Internal oblique and Transversalis muscle to the sheath of the Rectus, 
where they anastomose with the internal mammary and the deep epigastric 
arteries. Behind, the subcostal artery anastomoses with the first lumbar artery. 
Branches.-Each intercostal artery gives off numerous muscular branches (rami 
muscular es). 
Fig. 416.-Thoracic aorta. (Testut.) 
Lateral cutaneous. 
Posterior or dorsal branch. 
Muscular. 
Collateral intercostal. 668 
THE BLOOD-VASCULAR SYSTEM 
Lateral Cutaneous Branches {rami cutanei laterales) come off from each intercostal 
and take a similar course to that of the lateral cutaneous branch of the intercostal 
nerve. These arteries are distributed to the walls of the chest and to the mammary 
gland (rami mammarii laterales). 
Small branches pass to the mammary gland through the fourth, fifth, and sixth 
interspaces (rami mammarii medialis), and to the skin to the inner side of the 
nipple (rami cutanei arteriores). 
The portion of the artery considered here as the prolongation of the main trunk 
is called by Spalteholz and others the anterior branch (ramus anterior). 
The Posterior or Dorsal Branch (ramus posterior) of each intercostal artery passes 
backward to the inner side of the anterior costo-transverse ligament, and divides 
into an external branch (ramus cutaneus lateralis), and an internal branch (ramus 
cutaneus medialis), which are distributed to the muscles and integument of the 
back. Muscular branches (rami musculares) are given off by the dorsal branch soon 
after its origin. A spinal branch (ramus spinalis) comes off from the dorsal 
branch of the intercostal. It traverses the vertebral arches and enters the spinal 
canal through the intervertebral foramen, is distributed to the spinal cord and 
its membranes, and to the bodies of the vertebrae in the same manner as the 
lateral spinal branches from the vertebral. It gives off three branches, the 
neural, which accompanies the spinal nerve-roots, and is distributed to the mem- 
branes of the spinal cord. The post-central branch divides into ascending and 
descending branches, which, anastomosing with similar branches above and 
below, form a series of vertical arches in the back of the bodies of the verte- 
brae.1 The prelaminar branch is distributed to "the posterior wall of the spinal 
canal."2 
The Collateral Intercostal Branch comes off from the intercostal artery near the 
angle of the rib, and descends to the upper border of the rib below, along which 
it courses to anastomose with the anterior intercostal branch of the internal 
mammary or its branch, the musculo-phrenic. 
The two lower intercostals on each side have not constant collateral branches. 
Even when present they are of small size and end in the wall of the abdomen. 
Each collateral intercostal branch gives off muscular branches. 
Surgical Anatomy.-The position of the intercostal vessels should be borne in mind in 
performing the operation of paracentesis thoracis. The puncture should never be made nearer 
the middle line posteriorly than the angle of the rib, as the artery crosses the space internal to 
this point. In the lateral portion of the chest, where the puncture is usually made, the artery 
lies at the upper part of the intercostal space, and therefore the puncture should be made just 
above the upper border of the rib forming the lower boundary of the space. 
The Abdominal Aorta (Aorta Abdominalis) (Fig. 417). 
The abdominal aorta commences at the aortic opening of the Diaphragm, in 
front of the lower border of the body of the last dorsal vertebra, and, descending a 
little to the left side of the vertebral column, terminates on the body of the fourth 
lumbar vertebra, commonly a little to the left of the middle line,3 where it 
divides into the two common iliac arteries. It diminishes rapidly in size, in 
consequence of the many large branches which it gives off. As it lies upon the 
bodies of the vertebrae, the curve which it describes is convex forward, the 
greatest convexity corresponding to the third lumbar vertebra, which is a little 
above and to the left side of the umbilicus. 
1 Cunningham's Text-book of Anatomy. 2 Ibid. 
* Lord Lister, having accurately examined 30 bodies in order to ascertain the exact point of termination of 
this vessel, found it " either absolutely, or almost absolutely, mesial in 15, while in 13 it deviated more or less 
to the left, and in 2 was slightly to the right" (System of Surgery, edited by T. Holmes, 2d ed., vol. v. p. 652). 
-Ed. of 15th English edition. THE ABDOMINAL AORTA 
669 
Relations.-It is covered, in front, by the lesser omentum and stomach, behind 
which are the branches of the cceliac axis and the solar plexus; below these, by 
the splenic vein, the pancreas, the left renal vein, the transverse portion of the 
duodenum, the mesentery, and aortic plexus. Behind, it is separated from the 
lumbar vertebrae and intervening disks by the anterior common ligament and left 
Fig. 417.-The abdominal aorta and its branches. 
lumbar veins. On the right side it is in relation with the inferior vena cava (the 
right crus of the Diaphragm being interposed above), the vena azygos major 
thoracic duct, and right semilunar ganglion; on the left side, with the svmnathetic 
nerve and left semilunar ganglion. THE BLOOD-VASCULAR SYSTEM 
670 
Plan of the Relations of the Abdominal Aorta. 
In front. 
Lesser omentum and stomach. 
Branches of the coeliac axis and solar plexus. 
Splenic vein. 
Pancreas. 
Left renal vein. 
Transverse duodenum. 
Mesentery. 
Aortic plexus. 
Right side. 
Right crus of Diaphragm. 
Inferior vena cava. 
Vena azygos major. 
Thoracic duct. 
Right semilunar ganglion. 
Left side. 
Sympathetic nerve. 
Left semilunar ganglion. 
Abdominal 
Aorta. 
Behind. 
Left lumbar veins. 
Vertebral column. 
Surface Marking.-In order to map out the abdominal aorta on the surface of the abdomen, 
a line must be drawn from the middle line of the body, on a level with the distal extremity of 
the seventh costal cartilage, downward and slightly to the left, so that it just skirts the umbilicus, 
to a zone drawn round the body opposite the highest point of the crest of the ilium. This 
point is generally half an inch below and to the left of the umbilicus, but as the position of this 
structure varies with the obesity of the individual, it is not a reliable landmark as to the situation 
of the bifurcation of the aorta. 
Surgical Anatomy.-Aneurisms of the abdominal aorta near the coeliac axis communicate 
in nearly equal proportion with the anterior and posterior parts of the artery. 
When an aneurismal sac is connected with the back part of the abdominal aorta, it usually 
produces absorption of the bodies of the vertebrae, and forms a pulsating tumor that presents 
itself in the left hypochondriac or epigastric regions, and is accompanied by symptoms of dis- 
turbance in the alimentary canal. Pain is invariably present, and is usually of two kinds-a 
fixed and constant pain in the back, caused by the tumor pressing on or displacing the branches 
of the solar plexus and splanchnic nerves; and a sharp lancinating pain, radiating along those 
branches of the lumbar nerves which are pressed on by the tumor; hence the pain in the loins, 
the testes, the hypogastrium, and in the lower limb (usually of the left side). This form of 
aneurism usually bursts into the peritoneal cavity or behind the peritoneum in the left hypo- 
chondriac region; or it may form a large aneurismal sac, extending down as low as Poupart's 
ligament; hemorrhage in these cases being generally very extensive, but slowly produced, and 
not rapidly fatal. 
When an aneurismal sac is connected with the front of the aorta near the coeliac axis it 
forms a pulsating tumor in the left hypochondriac or epigastric regions, usually attended with 
symptoms of disturbance of the alimentary canal, as sickness, dyspepsia, or constipation, and 
is accompanied by pain, which is constant, but nearly always fixed in the loins, epigastrium, or 
some part of the abdomen; the radiating pain being rare, as the lumbar nerves are seldom 
implicated. This form of aneurism may burst into the peritoneal cavity or behind the peri- 
toneum, between the layers of the mesentery, or, more rarely, into the duodenum; it seldom 
extends backward so as to affect the spine. 
The abdominal aorta has been tied 15 times, and although none of the patients permanently 
recovered, still, as Prof. Keen's lived 48 days, the possibility of the re-establishment of the 
circulation is proved. In the lower animals this artery has been often successfully tied. The 
vessel may be reached in several ways. In the original operation, performed by Sir A. Cooper, 
in 1817, an incision was made in the linea alba, the peritoneum opened in front, the finger 
carried down amongst the intestines toward the spine, the peritoneum again opened behind by 
scratching through the mesentery, and the vessel thus reached. Or either of the operations 
described below for securing the common iliac artery may, by extending the dissection a suf- 
ficient distance upward, be made use of to expose the aorta. The chief difficulty in the 
dead subject consists in isolating the artery in consequence of its great depth; but in the 
living subject the embarrassment resulting from the proximity of the aneurismal tumor, and 
the great probability of disease in the vessel itself, add to the dangers and difficulties of this 
formidable operation so greatly that it is very doubtful whether it ought ever to be performed. 
The collateral circulation would be carried on by the anastomosis between the internal mam- THE ABDOMINAL AORTA 
671 
mary and the deep epigastric; by the free communication between the superior and inferior 
mesenteries if the ligature were placed above the latter vessel; or by the anastomosis between 
the inferior mesenteric and the internal pudic when (as is more common) the point of ligature is 
below the origin of the inferior mesenteric; and possibly by the anastomoses of the lumbar 
arteries with the branches of the internal iliac. 
During an amputation at the hip the circulation through the abdominal aorta may be com- 
manded by an assistant, who throws the entire weight of his body upon his rigidly extended 
forearm, the fist of which lies directly upon the patient's aorta (Macewen's method). The 
abdominal tourniquet is no longer used, as modern methods enable the surgeon to do a prac- 
tically bloodless hip-joint amputation (Wyeth's method, Senn's method, McBurney's method). 
Branches (Fig. 417).-The branches of the abdominal aorta are-the 
t>i • 
Phrenic 
r a • 
Coeliac Axis 
Gastric. 
Hepatic 
Splenic. 
Superior Mesenteric. 
Suprarenal. 
Renal. 
Spermatic in male. 
Ovarian in female. 
Inferior Mesenteric. 
Lumbar. 
Sacra Media. 
Branches.-The branches of the abdominal aorta may be divided into two 
sets: 1. Those supplying the viscera {rami vicerales). 2. Those distributed to 
the walls of the abdomen (rami parietales). 
J isceral Branches. 
Coeliac Axis 
Gastric. 
Hepatic. 
Splenic. 
Parietal Branches. 
Inferior Phrenic. 
Lumbar. 
Sacra Media. 
Superior Mesenteric.. 
Inferior Mesenteric. 
Suprarenal. 
Renal. 
Spermatic or Ovarian. 
To expose the eceliac axis raise the liver, draw down the stomach, and then tear through the 
layers of the lesser omentum. 
The Cceliac Axis or Artery (a. coeliaca) (Figs. 417, 418, and 419).-The coeliac 
axis is a short thick trunk, about half an inch in length, which arises from the 
aorta, close to the margin of the opening in the Diaphragm, behind the posterior 
parietal peritoneum, above the pancreas, and below the twelfth dorsal vertebra, 
and, passing nearly horizontally forward (in the erect posture), divides into three 
large branches, the gastric, hepatic, and splenic, occasionally giving off one of the 
phrenic arteries. 
Relations.-It is covered by the lesser omentum. On the right side it is in 
relation with the right semilunar ganglion and the lobus Spigelii; on the lejt side, 
with the left semilunar ganglion and cardiac end of the stomach. Below, it rests 
upon the upper border of the pancreas. 
The Gastric or Coronary Artery (a. gastrica sinistra) (Figs. 418 and 419), the small- 
est of the three branches of the cceliac axis, passes upward and to the left side, 
behind the peritoneum of the lesser peritoneal cavity, raising this portion of the 
peritoneum into a fold, known as the left or secondary pancreatico-gastric fold. It 
continues this course until it nearly reaches the lesser curvature of the stomach just 
below the cardia. It then turns to the front and curves forward to the cardiac 
orifice of the stomach, distributing branches to the oesophagus which anastomose 
with the aortic oesophageal arteries; others supply the cardiac end of the stomach, 
inosculating with branches of the splenic artery; it then passes from left to 
right, along and upon the lesser curvature of the stomach and beneath the 
peritoneum to the pylorus, lying in its course between the layers of the lesser 
omentum, and sometimes dividing into two vessels, which run along each side THE BLOOD-VASCULAR SYSTEM 
672 
of the lesser curvature. One vascular arch gives branches to the anterior wall 
of the stomach and the other to the posterior wall (Fig. 886), and both give 
them to the lesser omentum or the single artery gives branches to both sur- 
faces of the organ and to the lesser omentum: at its termination it anastomoses 
with the pyloric branch or the two pyloric branches of the hepatic. It gives off 
gastric branches to both the anterior and posterior surfaces of the stomach, 
branches to the lesser omentum, a small hepatic branch, to the left lobe of the liver 
and oesophageal branches (rami cesophagei) which anastomose with oesophageal 
branches from the thoracic aorta and the inferior phrenic. 
Cystic artery. 
Probe passed through foramen of Winslow. 
Fig. 418.-The coeliac axis and its branches, the liver having been raised and the lesser omentum removed. 
The Hepatic Artery (a. hepatica) (Figs. 418 and 419) in the adult is intermediate 
in size between the gastric and splenic; in the fcetus it is the largest of the three 
branches of the cceliac axis. It is first directed forward and to the right, in the 
right pancreatico-gastric fold, to the upper margin of the pyloric end of the 
stomach, forming the lower boundary of the foramen of Winslow. It then passes 
upward between the layers of the lesser omentum, and in front of the foramen of 
Winslow, to the transverse fissure of the liver, where it divides into two branches, 
right and left, which supply the corresponding lobes of that organ, accompanying 
the ramifications of the vena portre and hepatic duct. The hepatic artery, in 
its course along the right border of the lesser omentum, is in relation with the 
ductus communis choledochus and portal veins, the duct lying to the right of 
the artery and the vena porta? behind. THE ABDOMINAL AORTA 
673 
Its branches (Figs. 418 and 419) are-the 
Pyloric. 
Gastro-duodenalis 
Gastro-epiploica Dextra. 
Pancreatico-duodenalis Superior 
Cystic. 
The pyloric or superior pyloric branch (a. gastrica dextra) arises from the 
hepatic, above the pylorus, descends between the layers of the lesser omentum 
to the pyloric end of the stomach, and passes from right to left along its lesser cur- 
vature, supplying it with branches and inosculating with the gastric branches of 
the coronary artery. The vessel often divides into two vascular arches to anas- 
tomose with two vascular arches from the gastric. 
Fig. 419.-The cceliac axis and its branches, the stomach having been raised and the transverse mesocolon 
removed (semi-diagrammatic). 
The gastro-duodenalis (Fig. 419) is a short but large branch, which descends 
near the pylorus, behind the first portion of the duodenum, and divides at the 
lower border of this viscus into two branches, the gastro-epiploica dextra and the 
pancreatico-duodenalis superior. Previous to its division, it gives off two or three 
small inferior pyloric branches, to the pyloric end of the stomach and pancreas. 
The gastro-epiploica dextra runs from right to left along but distinctly below 
the greater curvature of the stomach, between the layers of the great omentum, 
anastomosing about the middle of the lower border of the stomach with the gastro- 
epiploica sinistra from the splenic artery. This vessel gives off numerous branches, 674 
THE BLOOD-VASCULAR SYSTEM 
some of which ascend to supply both surfaces of the stomach, whilst others 
descend to supply the great omentum (rami epiploici). 
The pancreatico-duodenalis superior descends between the contiguous margins 
of the duodenum and pancreas. It supplies the head of the pancreas by means 
of the rami pancreatica, and the duodenum by means of the rami duodenalis, 
and anastomoses with the inferior pancreatico-duodenal branch of the superior 
mesenteric artery and with the pancreatic branches of the splenic. 
The cystic artery (a. cystica) (Fig. 418), usually a branch of the right hepatic, 
passes downward and forward along the cystic duct to the gall-bladder, and 
divides into two branches, one of which ramifies on its free surface beneath 
the peritoneum, the other between the gall-bladder and the substance of the 
liver. 
The Splenic Artery (a. lienalis) (Figs. 418 and 419), in the adult, is the largest of 
the three branches of the coeliac axis, and is remarkable for the extreme tortuosity 
of its course. It passes horizontally to the left side, behind the peritoneum and 
along the upper border of the pancreas, accompanied by the splenic vein, which lies 
below it, and on arriving near the spleen divides into branches, some of which 
enter the hilum of that organ to be distributed to its structure, whilst others are 
distributed to the pancreas and great end of the stomach. Its branches are-the 
Pancreaticae Parvae. 
Pancreatica Magna. 
Gastric (Vasa Brevia). 
Gastro-epiploica Sinistra. 
Rami Lienalis. 
The pancreatic branches (rami pancreatici) are numerous small branches 
derived from the splenic as it runs behind the upper border of the pancreas, 
supplying its middle and left parts. One of these, larger than the rest, is given 
off from the splenic near the left extremity of the pancreas; it runs from left 
to right near the posterior surface of the gland, following the course of the pan- 
creatic duct, and is called the pancreatica magna. The others are called the 
pancreaticae parvoe. These vessels anastomose with the pancreatic branches of the 
pancreatico-duodenal arteries, derived from the hepatic on the one hand and 
superior mesenteric on the other. 
The gastric branches or vasa brevia (aa. gastrica; breves) consists of from five to 
seven small branches, which arise either from the termination of the splenic 
artery or from its terminal branches, and, passing from left to right, between 
the layers of the gastro-splenic omentum, are distributed to the great curvature 
of the stomach, anastomosing with branches of the gastric and gastro-epiploica 
sinistra arteries. 
The gastro-epiploica sinistra, the largest branch of the splenic, runs from left 
to right along but distinctly below the great curvature of the stomach, between 
the layers of the great omentum, and anastomoses with the gastro-epiploica 
dextra. In its course it distributes several branches to the stomach, which 
ascend upon both surfaces; others descend to supply the omentum. 
The rami lienales leave the splenic artery in the hilum and pass into the spleen. 
Surgical Anatomy.-The operation of pylorectomy can be made an almost bloodless pro- 
cedure by tying the gastric, the pyloric, and the right and left gastro-epiploic arteries. "The 
gastric is doubly tied about one inch below the cardiac orifice at a point where it joins the lesser 
curvature and is divided between the ligatures. The superior pyloric is doubly tied and divided. 
The fingers are passed beneath the pylorus, raising the gastro-colic omentum from the trans- 
verse mesocolon, and in this way safe ligation behind the pylorus of the right gastro-epiploic 
artery, or in most cases its parent vessel, the gastro-duodenal, is secured. The left gastro- 
epiploic is now tied at an appropriate point, and the necessary amount of gastro-colic omentum 
doubly tied and cut."1 
1 William J. Mayo. Annals of Surgery, March, 1904. THE ABDOMINAL AORTA 
675 
The Superior Mesenteric Artery (a. mesenterica superior) (Figs. 417 and 420). 
-The superior mesenteric artery supplies the whole length of the small intestine, 
except the first part of the duodenum; it also supplies the ciecum and the ascending 
and transverse colon; it is a vessel of large size, arising from the forepart of the 
aorta about a quarter of an inch below the coeliac axis; being covered at its origin 
by the splenic vein and pancreas. It passes forward, between the pancreas and the 
transverse portion of the duodenum, crosses in front of this portion of the intes- 
tine, and descends between the layers of the mesentery to the right iliac fossa, 
where, considerably diminished in size, it anastomoses with one of its own branches 
-viz., the ileo-colic. In its course it forms an arch, the convexity of which is 
directed forward and downward to the left side, the concavity backward and 
upward to the right. It is accompanied by the superior mesenteric vein, and is 
surrounded by the superior mesenteric plexus of nerves. 
In order to expose the superior mesenteric artery raise the great omentum and transverse 
colon, draw down the small intestines, and cut through the peritoneum where the transverse 
mesocolon and mesentery join; the artery will then be exposed just as it issues from beneath 
the lower border of the pancreas 
Branches.-Its branches are-the 
Inferior Pancreatico-duodenal. 
Vasa Intestini Tenuis. 
Ileo-colic. 
Right Colic. 
Middle Colic. 
The Inferior Pancreatico-duodenal (a. pancreaticoduodenalis inferior) is given 
off from the superior mesenteric, or from its first intestinal branch behind the 
pancreas. It courses to the right between the head of the pancreas and duodenum, 
and then ascends to anastomose with the superior pancreatico-duodenal artery. 
It distributes branches to the head of the pancreas and to the transverse and 
descending portions of the duodenum. 
The Vasa Intestini Tenuis (aa. intestinales) arise from the convex side of the 
superior mesenteric artery. They are usually from twelve to fifteen in number, 
and are distributed to the jejunum (aa. jejunales) and ileum (aa. ileoe). They 
run parallel with one another between the layers of the mesentery, each vessel 
dividing into two branches, which unite with similar branches on each side, 
forming a series of arches the convexities of which are directed toward the 
intestine. From this first set of arches branches arise, which again unite with 
similar branches from either side, and thus a second series of arches is formed; 
and from these latter, a third and a fourth, or even a fifth, series of arches is 
constituted, diminishing in size the nearer they approach the intestine. From 
the terminal arches numerous small straight vessels arise which encircle the 
intestine, upon which they are distributed, ramifying between its coats. Through- 
out their course small branches are given off to the glands and other structures 
between the layers of the mesentery. (See the description of the vascular loops 
in the section upon the Intestines. The form and arrangement of the loops 
have been studied by Monks, of Boston.) 
The Ileo-colic Artery (a. ileocolica) is the lowest branch given off from the 
concavity of the superior mesenteric artery. It descends between the layers of 
the mesentery to the right iliac fossa, where it divides into two branches. Of 
these, the inferior division inosculates with the termination of the superior mesen- 
teric artery, forming with it an arch, from the convexity of which branches 
proceed to supply the termination of the ileum, the caecum, the vermiform 
appendix, and the ileo-caecal valve. The superior division inosculates with 
the colica dextra and supplies the commencement of the colon. 
The Right Colic Artery (a. colica dextra) arises from about the middle of the 
concavity of the superior mesenteric artery, and, passing behind the peritoneum THE BLOOD-VASCULAR SYSTEM 
676 
to the middle of the ascending colon, divides into two branches-a descending 
branch, which inosculates with the ileo-colic, and an ascending branch, which 
anastomoses with the colica media. These branches form arches, from the 
convexity of which vessels are distributed to the ascending colon. The branches 
of this vessel are covered with peritoneum only on their anterior aspect. 
The Middle Colic Artery (a. colica media) arises from the upper part of the 
concavity of the superior mesenteric, and, passing forward between the layers 
of the transverse mesocolon, divides into two branches, the one on the right 
side inosculating with the colica dextra; that on the left side, with the colica 
sinistra, a branch of the inferior mesenteric. From the arches formed by their 
inosculation branches are distributed to the transverse colon. The branches 
of this vessel lie between the two layers of the transverse mesocolon. 
Fig. 420.-The superior mesenteric artery and its branches. 
Blood-supply of the Right Iliac Fossa.-The descending branch of the right colic artery by 
anastomosing with the ascending branch of the ileo-colic artery forms a vascular loop. The 
union of the descending branch of the ileo-colic artery with the terminal vessel of the superior 
mesenteric artery forms another vascular loop. These two loops give off secondary loops, and 
from the secondary loops come the vessels which supply the appendix, the caecum, and the 
lower end of the ileum. The branch which goes to the appendix is called the appendicular 
artery (a. appendicularis). If there is a distinct meso-appendix the artery passes along its 
unattached edge. If there is a rudimentary meso-appendix or no meso-appendix the artery THE ABDOMINAL AORTA 
677 
usually lies upon the appendix from base to tip beneath the peritoneal covering. In females 
the appendix may receive an additional vessel from the ovarian, which vessel lies in the 
appendiculo-ovarian ligament. 
The Inferior Mesenteric Artery (a. mesenterica inferior) (Figs. 417 and 421).- 
The inferior mesenteric artery supplies the descending colon, the sigmoid flexure 
of the colon and the greater part of the rectum. It is smaller than the superior 
mesenteric, and arises from the left side of the aorta, between one and two inches 
above the division of that vessel into the common iliacs. It passes downward 
to the left iliac fossa, and then descends between the layers of the mesorectum, 
Middle hxmorrhoidal. 
Inferior hsemorrhoidal.^ 
Fig. 421.-The inferior mesenteric and its branches. 
into the pelvis, under the name of the superior hsemorrhoidal artery. It lies at first 
in close relation with the left side of the aorta, and then passes as the superior 
haemorrhoidal in front of the left common iliac artery. 
In order to expose the inferior mesenteric artery draw the small intestines and mesentery over 
to the right side of the abdomen, raise the transverse colon toward the thorax, and divide the 
peritoneum covering the front of the aorta. 
Branches.-Its branches are-the 
Left Colic. 
Sigmoid. 
Superior Heemorrhoidal. THE BLOOD-VASCULAR SYSTEM 
678 
The Left Colic Artery (a. colica sinistra) passes behind the peritoneum, in 
front of the left kidney, to reach the descending colon, and divides into two 
branches-an ascending branch, which inosculates with the colica media; and 
a descending branch, which anastomoses with the sigmoid artery. From the 
arches formed by these inosculations branches are distributed to the descending 
colon. 
The Sigmoid Arteries (aa. sigmoideoe).-Xs a rule there are two of these vessels, 
but may be three. They run obliquely downward across the Psoas muscle to the 
sigmoid flexure of the colon, and divide into branches which supply that part of 
the intestine, anastomosing above with the left colic, and below with the superior 
hsemorrhoidal artery. 
'The Superior Hsemorrhoidal Artery (a. hoemorrhoidalis superior) (Figs. 421 and 
424), the continuation of the inferior mesenteric, descends into the pelvis between 
the layers of the mesorectum, crossing, in its course, the ureter and left common 
iliac vessels. Opposite the middle of the sacrum it divides into two branches, 
which descend one on each side of the rectum, and about five inches from the 
anus break up into several small branches, which pierce the muscular coat of the 
bowel and run downward, as straight vessels, placed at regular intervals from 
each other in the wall of the gut between its muscular and mucous coat, to the 
level of the internal sphincter; here they form a series of loops around the lower 
end of the rectum, and communicate with the middle hsemorrhoidal arteries which 
are branches of the internal iliac and with the inferior hsemorrhoidal branches 
of the internal pudic. 
Fig. 422.-Corrosion anatomy. Hyrtl's exsanguinated renal zone. (Byron Robinson.) 
The Suprarenal Artery (a. suprarenalis media) (Fig. 417).-A suprarenal or 
capsular artery arises, one on each side of the aorta, opposite the superior mesenteric 
artery. It is a small vessel which passes obliquely upward and outward, over 
the crura of the Diaphragm, to the under surface of the suprarenal capsule, to 
which it is distributed, anastomosing with capsular branches from the phrenic 
and renal arteries. In the adult these arteries are of small size; in the foetus 
they are as large as the renal arteries. 
The Renal Arteries (aa. renales) (Fig. 417).-The renal arteries are two 
large trunks which arise from the sides of the aorta immediately below the superior THE ABDOMINAL AORTA 
679 
mesenteric artery. Fach is directed outward across the crus of the Diaphragm, 
so as to form nearly a right angle with the aorta. The right is longer than the 
left, on account of the position of the aorta; it passes behind the inferior vena 
cava. The left is somewhat higher than the right. Before reaching the hilum 
of the kidney, each artery usually divides into four branches. Two of these vessels 
enter the anterior portion and two the posterior portion of the kidney. There 
may be but one renal artery; there may be two, three, four, or five branches. The 
greater number of the branches generally lie between the renal vein and ureter, the 
vein being in front of the arteries, the ureter behind. The anterior branches supply 
three-fourths of the kidney, the posterior supply one-fourth. Each vessel gives 
off a small branch to the suprarenal capsule (a. suprarenalis inferior) and branches 
to the ureter, ureteral branches, and to the surrounding cellular tissue and muscles, 
perirenal branches. Hyrtl, in 1870, pointed out that the renal artery gives off a 
branch which divides and supplies the dorsal or posterior portion of the kidney and 
Fig. 423.-Corrosion anatomy. The renal vascular blades opened like a book. (Byron Robinson.) 
its pelvis, and a branch which divides and supplies the ventral or anterior portion 
of the kidney and its pelvis. The two circulations are distinct and do not anas- 
tomose even at the periphery. Between these two sets of vessels is a bloodless zone 
called by Byron Robinson the exsanguinated renal zone of Hyrtl, which does not cor- 
respond to the median line, but is "one-half inch dorsal to the lateral longitudinal 
renal border."1 The ventral or anterior segment is much the larger. In very rare 
instances the bloodless zone corresponds to the median line (Kummel). An incision 
of the middle third of the kidney exactly at the junction of the two segments does 
not divide vessels. As the incision approaches either pole there is danger of cutting 
a branch (Schede). Frequently there is a second renal artery, which is given off 
from the abdominal aorta either above or below the renal artery proper, the former 
being the more common position. Instead of entering the kidney at the hilum, 
an accessory renal artery usually pierces the upper or the lower part of the gland. 
The Spermatic Arteries (aa. spermaticoe internee') (Fig. 417).-The internal 
spermatic arteries are distributed to the testes. They are two slender vessels of 
1 Byron Robinson. The Circulation of the Kidney, American Journal of Surgery. 680 
THE BLOOD-VASCULAR SYSTEM 
considerable length, which arise from the front of the aorta a little below the renal 
arteries. Each artery passes obliquely outward and downward behind the peri- 
toneum, resting on the Psoas muscle, the right spermatic lying in front of the 
inferior vena cava, the left behind the sigmoid flexure of the colon. It then crosses 
obliquely over the ureter (to which it sends a few branches) and the lower part 
of the external iliac artery to reach the internal abdominal ring, through which 
it passes, and accompanies the other constituents of the spermatic cord along 
the inguinal canal to the scrotum, where it becomes tortuous and is prolonged 
as the testicular artery, which accompanies the vas deferens, anastomosing with 
the artery of the vas deferens and is distributed to the epididymis, the back part 
of the tunica albuginea, and the substance of the testes. The spermatic artery 
in the inguinal canal gives oft' cremasteric branches to supply the Cremaster muscle. 
In the canal and scrotum the artery lies behind the pampiniform plexus and in 
front of the vas deferens. 
The Ovarian Arteries (aa. ovaricoe).-The ovarian arteries (Fig. 425) are 
the corresponding arteries in the female to the spermatic in the male. They 
supply the ovaries, are shorter than the spermatic, and do not pass out of 
the abdominal cavity. The origin and course of the first part of the artery are the 
same as the spermatic in the male, but on arriving at the margin of the pelvis the 
ovarian artery passes inward, between the two layers of the broad ligament of the 
uterus, to be distributed to the ovary, ovarian branches. Branches go to the Fallopian 
tube,tubal branches, the ureter, ureteral branches, and the broad ligament, ligamentous 
branches. A branch passes on to the side of the uterus and anastomoses with the 
uterine arteries, uterine branch. Other offsets are continued along the round 
ligament through the inguinal canal, to the integument of the labium and groin. 
At an early period of foetal life, when the testes or ovaries lie by the side of 
the spine below the kidneys, the spermatic or ovarian arteries are short; but as 
these organs descend from the abdomen into the scrotum or pelvis, the arteries 
become gradually lengthened. 
The Inferior Phrenic Arteries (aa. phrenicoe infer lores') (Fig. 417).-The inferior 
phrenic arteries are two small vessels which present much variety in their origin. 
They may arise separately from the front of the aorta, immediately above the 
coeliac axis, or by a common trunk, which may spring either from the aorta or 
from the cceliac axis. Sometimes one is derived from the aorta, and the other 
from one of the renal arteries. In only one out of thirty-six cases examined did 
these arteries arise as two separate vessels from the aorta. They diverge from 
one another across the crura of the Diaphragm, and then pass obliquely upward 
and outward upon the under surface of the Diaphragm. The left phrenic passes 
behind the oesophagus and runs forward on the left side of the oesophageal 
opening. The right phrenic passes behind the inferior vena cava, and ascends 
along the right side of the aperture for transmitting that vein. Near the back 
part of the central tendon each vessel divides into two branches. The internal 
branch runs forward to the front of the thorax, supplying the Diaphragm and 
anastomosing with its fellow of the opposite side, and with the musculo-phrenic 
and comes nervi phrenici branches of the internal mammary. The external branch 
passes toward the side of the thorax and inosculates with the intercostal arteries. 
The internal branch of the right phrenic gives off a few vessels to the inferior 
vena cava, and the left one some branches to the oesophagus. Each vessel also 
sends capsular branches (rami suprarenales superior) to the suprarenal capsule 
of its own side. The spleen on the left side and the liver on the right also 
receive a few branches from these vessels. 
The Lumbar Arteries (aa. lumbales).-The lumbar arteries are analogous to 
the intercostals. They are usually four in number on each side, and arise from 
the back part of the aorta, nearly at right angles with that vessel. They pass THE COMMON ILIAC ARTERIES 
681 
outward and backward, around the sides of the bodies of the lumbar vertebrae, 
behind the sympathetic nerve and the Psoas magnus muscle, those on the right 
side being covered by the inferior vena cava, and the two upper ones on each side 
by the crura of the Diaphragm. In the interval between the transverse processes 
of the vertebrae each artery gives off a dorsal branch. 
After the formation of the dorsal branch the artery passes outward, having 
a variable relation to the Quadratus lumborum muscle. Most frequently the 
first lumbar passes in front of the muscle and the others behind it; sometimes 
the order is reversed and the lowest lumbar passes in front of the muscle. At 
the outer border of the Quadratus they are continued between the abdominal 
muscles, anastomose with branches of the epigastric and internal mammary 
in front, the intercostals above, and branches of the ilio-lumbar and circumflex 
iliac below. The lumbar arteries are also distributed to the skin of the sides of 
the abdomen. 
The Dorsal Branch (ramus dorsalis} gives off, immediately after its origin, a 
spinal branch, which enters the spinal canal. The dorsal branch then continues 
its course backward between the transverse processes, and is distributed to the 
muscles and integument of the back, anastomosing with similar branches of the 
adjacent lumbar arteries and with the posterior branches of the intercostal 
arteries. 
The Spinal Branch (ramus spinalis} enters the spinal canal through the inter- 
vertebral foramen, to be distributed to the spinal cord and its membranes and 
to the bodies of the vertebrae in the same manner as the lateral spinal branches 
from the vertebral (see page 638). 
The Middle Sacral Artery (a. sacralis media} (Fig. 424).-The middle sacral 
artery is a small vessel, which arises from the back part of the aorta just at its bifur- 
cation. It descends upon the last lumbar vertebra, and along the middle line of the 
front of the sacrum, to the upper part of the coccyx, where it anastomoses with 
the lateral sacral arteries, and terminates in a minute branch, which runs down 
to the situation of the body described as Luschka's gland. It gives off on each 
side opposite the body of the fifth lumbar vertebra a branch known as the a. 
lumbalis ima. From the middle sacral artery branches arise which run through 
the mesorectum to supply the posterior surface of the rectum. Other branches 
are given off on each side, which anastomose with the lateral sacral arteries, 
and send off small offsets which enter the anterior sacral foramina. 
The artery is the representative of the caudal prolongation of the aorta of 
animals, and its lateral branches correspond to the intercostal and lumbar arteries 
in the dorsal and lumbar regions. 
THE COMMON ILIAC ARTERIES (AA. ILIAC AS COMMUNES) (Figs. 417, 424). 
The abdominal aorta divides into the two common iliac arteries. The bifurca- 
tion usually takes place on the left side of the body of the fourth lumbar ver- 
tebra. The common iliac arteries are about two inches in length; diverging 
from the termination of the aorta, they pass downward and outward to the margin 
of the pelvis, each divides opposite the intervertebral substance, between the last 
lumbar vertebra and the sacrum, into two branches, the internal and external 
iliac arteries, the latter supplying the lower extremity; the former, the viscera and 
parietes of the pelvis. 
The right common iliac is somewhat longer than the left, and passes more 
obliquely across the body of the last lumbar vertebra. In front of it are the 
peritoneum, the small intestines, branches of the sympathetic nerve, and, at its 
point of division, the ureter. Behind, it is separated from the fourth and fifth 682 
THE BLOOD- VASCULAR SYSTEM 
lumbar vertebrae, with the intervening intervertebral disk, by the two common 
iliac veins. On its outer side, it is in relation with the inferior vena cava and 
the right common iliac vein, above, and the Psoas magnus muscle below. 
The left common iliac is in relation, in front, with the peritoneum, branches 
of the sympathetic nerve, and the superior haemorrhoidal artery; and is crossed 
at its point of bifurcation by the ureter. It rests on the bodies of the fourth and 
fifth lumbar vertebrae, with the intervening intervertebral disk. The left common 
iliac vein lies partly on the inner side, and partly beneath the artery; on its outer 
side, the artery is in relation with the Psoas magnus muscle. 
In front. 
Peritoneum. 
Small intestines. 
Sympathetic nerves. 
Ureter. 
Plan of the Relations of the Common Iliac Arteries 
In jront. 
Peritoneum. 
Sympathetic nerves. 
Superior haemorrhoidal artery. 
Ureter. 
Outer side. 
Vena cava. 
Right common 
iliac vein. 
Psoas muscle. 
Inner side. 
Left common 
iliac vein. 
Outer side. 
Psoas magnus 
muscle. 
Right 
Common 
Iliac. 
Left 
Common 
Iliac. 
Behind. 
Fourth and fifth lumbar vertebrae. 
Right and left common iliac veins. 
Behind. 
Fourth and fifth lumbar vertebrae. 
Left common iliac vein. 
Branches.-The common iliac arteries give off small branches to the perito- 
neum, Psoas magnus, ureters, and the surrounding cellular tissue, and occasionally 
give origin to the ilio-lumbar or renal arteries. 
Peculiarities.-The point of origin varies according to the bifurcation of the aorta. In 
three-fourths of a large number of cases the aorta bifurcated either upon the fourth lumbar 
vertebra or upon the intervertebral disk between it and the fifth, the bifurcation being, in one 
case out of nine below, and in one out of eleven above, this point. In ten out of every thirteen 
cases the vessel bifurcated within half an inch above or below the level of the crest of the ilium, 
more frequently below than above. 
The point of division is subject to great variety. In two-thirds of a large number of cases 
it was between the last lumbar vertebra and the upper border of the sacrum, being above that 
point in one case out of eight and below it in one case out of six. The left common iliac artery 
divides lower down more frequently than the right. 
The relative length, also, of the two common iliac arteries varies. The right common iliac 
was the longer in sixty-three cases, the left in fifty-two, whilst they were both equal in fifty- 
three. The length of the arteries varied in five-sevenths of the cases examined from an inch 
and a half to three inches; in about half of the remaining cases the artery was longer and in 
the other half shorter, the minimum length being less than half an inch, the maximum four 
and a half inches. In two instances the right common iliac has been found wanting, the external 
and internal iliacs arising directly from the aorta. 
Surface Marking. -Draw a zone around the body opposite the highest part of the crest of 
the ilium; in this line take a point half an inch to the left of the middle line. From this draw 
two lines to points midway between the anterior superior spines of the ilium and the symphysis 
pubis. These two diverging lines will represent the course of the common and external iliac 
arteries. Draw a second zone round the body corresponding to the level of the anterior superior 
spines of the ilium: the portion of the diverging lines between the two zones will represent the 
course of the common iliac artery; the portion below the lower zone, that of the external iliac 
artery. 
Surgical Anatomy.-The application of a ligature to the common iliac artery may be 
required on account of aneurism or hemorrhage implicating the external or internal iliacs. 
Now that the surgeon no longer dreads opening the peritoneal cavity, there can be no question 
that the easiest and best method of tying the artery is by a transperitoneal route. The abdomen 
is opened by an incision in either the semilunar line or the linea alba; the intestines are drawn 
to one side and the peritoneum covering the artery divided. The sheath is then opened, and 
the needle passed from within outward. On the right side great care must be exercised in THE INTERNAL ILIAC ARTERY 
683 
passing the needle, since both the common iliac veins lie behind the artery. After the vessel 
has been tied the incision in the peritoneum over the artery should be sutured. Formerly there 
were two different methods by which the common iliac artery was tied without opening the 
peritoneal cavity: 1, an anterior or iliac incision, by which the vessel is approached more directly 
from the front; and 2, a posterior abdominal or lumbar incision, by which the vessel is reached 
from behind. If the surgeon select the iliac region, a curved incision, from five to eight inches 
in length, according to the amount of fat, is made, commencing just outside the middle of 
Poupart's ligament and a finger's breadth above it, and carried outward toward the anterior 
superior iliac spine, then upward toward the ribs, and finally curving inward toward the umbili- 
cus. The abdominal muscles and transversalis fascia are divided, and the peritoneum raised 
upward and inward until the Psoas is reached. The artery will be found on the inner side of 
this muscle, and is to be cleared with a director, especial care being taken on the right side, as 
here the common iliac veins lie behind the artery. The aneurism needle is to be passed from 
within outward. But if the aneurismal tumor should extend high up in the abdomen, along 
the external iliac, it is better to select the posterior or lumbar route, making an incision partly in 
the abdomen, partly in the loin. The incision is commenced at the anterior extremity of the 
last rib, proceeding directly downward to the ilium; it is then curved forward along the crest of 
the ilium and a little above it to the anterior superior spine of that bone. The abdominal mus- 
cles having been cautiously divided in succession, the transversalis fascia must be carefully cut 
through, and the peritoneum, together with the ureter, separated from the artery and pushed 
aside; the sacro-iliac articulation must then be felt for, and upon it the vessel will be felt pulsat- 
ing, and may be fully exposed in close connection with the accompanying vein. On the right 
side both common iliac veins, as well as the inferior vena cava, are in close connection with the 
artery, and must be carefully avoided. On the left side the vein usually lies on the inner side 
and behind the artery; but it occasionally happens that the two common iliac veins are joined on 
the left instead of the right side, which would add much to the difficulty of an operation in such 
a case. The common iliac artery may be so short that danger may be apprehended from sec- 
ondary hemorrhage if a ligature is applied to it. It would be preferable, in such a case, to tie 
both the external and internal iliacs near their origin. 
Collateral Circulation.-The principal agents in carrying on the collateral circulation after 
the application of a ligature to the common iliac are-the anastomoses of the hsemorrhoidal 
branches of the internal iliac with the superior hsemorrhoidal from the inferior mesenteric; the 
anastomoses of the uterine and ovarian arteries and of the vesical arteries of opposite sides; of 
the lateral sacral with the middle sacral artery; of the epigastric with the internal mammary, 
inferior intercostal, and lumbar arteries; of the circumflex iliac with the lumbar arteries; of the 
ilio-lumbar with the last lumbar artery; of the obturator artery, by means of its pubic branch, 
with the vessel of the opposite side and with the deep epigastric. 
Compression of the Common Iliac Arteries.-The common iliac arteries may be com- 
pressed by Davy's lever. The instrument consists of a gum-elastic tube about two feet long, 
in which fits a round wooden "lever" considerably longer than the tube. A small quantity 
of olive oil having been injected into the rectum, the gum-elastic tube, softened in hot water, 
is passed into the bowel sufficiently far to permit its pressing upon the common iliac artery 
as it lies in the groove between the last lumbar vertebra and the Psoas muscle. The wooden 
lever is then inserted into the tube, and the projecting end carried toward the opposite thigh 
and raised, when it acts as a lever of the first order, the anus being the fulcrum. In cases where 
the mesorectum is abnormally short it may be impossible, without unjustifiable force, to com- 
press the artery on the right side. In amputation of the hip-joint the common iliac can be 
compressed most certainly and safely by opening the abdomen and compressing the vessel by 
means of the fingers against the Psoas muscle (McBurney's method). 
The Internal Iliac Artery (Figs. 417, 424). 
The internal iliae or hypogastric artery (a. hypogastrica} supplies the walls and 
viscera of the pelvis, the generative organs, and inner side of the thigh. It is 
a short thick vessel, smaller in the adult than the external iliac, and about an 
inch and a half in length. It arises at the point of bifurcation of the common 
iliac, and, passing downward to the upper margin of the great sacro-sciatic 
foramen, divides into two large trunks, an anterior and posterior; from its anterior 
division a partially obliterated cord, a part of the foetal hypogastric artery, extends 
forward to the bladder. 
Relations.-In front, with the ureter, which is between the artery and the 
peritoneum. Behind, with the internal iliac vein, the himbo-sacral cord, and 
Pyriformis muscle. By its outer side, near its origin, with the Psoas magnus muscle. 684 
THE BLOOD-VASCULAR SYSTEM 
Plan of the Relations of the Internal Iliac Artery. 
In front. 
Peritoneum. 
Ureter. 
Outer side. 
Psoas magnus. 
Internal 
Iliac. 
Behind. 
Internal iliac vein. 
Lumbo-sacral cord. 
Pyriformis muscle. 
■Heo-lumbar. 
Gluteal. 
Fig. 424.-Arteries of the pelvis. 
In the foetus the hypogastric artery is twice as large as the external iliac, and 
appears to be the continuation of the common iliac. Instead of dipping into 
the pelvis, it passes forward to the bladder, and ascends along the sides of that 
viscus to its summit, to which it gives branches; it then passes upward along the 
back part of the anterior wall of the abdomen to the umbilicus, converging 
toward its fellow of the opposite side. Having passed through the umbilical THE INTERNAL ILIAC ARTERY 
685 
opening, the two arteries twine round the umbilical vein in the umbilical cord, 
and ultimately ramify in the placenta. The portion of the vessel within the 
abdomen is called the hypogastric artery; the portion external to that cavity, the 
umbilical artery. 
At birth, when the placental circulation ceases, the upper portion of the hypo- 
gastric artery, extending from the summit of the bladder to the umbilicus, con- 
tracts, and ultimately dwindles to a solid fibrous cord; but the lower portion, 
extending from its origin (in what is now the internal iliac artery) for about an 
inch and a half to the wall of the bladder, and thence to the summit of that organ, 
is not totally impervious, though it becomes considerably reduced in size, and 
serves to convey blood to the bladder under the name of the superior vesical 
artery. 
Peculiarities as Regards Length. -In two-thirds of a large number of cases the length of 
the internal iliac varied between an inch and an inch and a half; in the remaining third it was 
more frequently longer than shorter, the maximum length being three inches, the minimum 
half an inch. 
The lengths of the common and internal iliac arteries bear an inverse proportion to each 
other, the internal iliac artery being long when the common iliac is short, and vice versa. 
As Regards its Place of Division.-The place of division of the internal iliac varies 
between the upper margin of the sacrum and the upper border of the sacro-sciatic foramen. 
The arteries of the two sides in a series of cases often differed in length, but neither seemed 
constantly to exceed the other. 
Surgical Anatomy.-The application of a ligature to the internal iliac artery may be 
required in cases of aneurism or hemorrhage affecting one of its branches. The vessel may be 
secured by making an incision through the abdominal parietes in the iliac region in a direction 
and to an extent similar to that for securing the common iliac; the transversalis fascia having 
been cautiously divided, and the peritoneum pushed inward from the iliac fossa toward the 
pelvis, the finger may feel the pulsation of the external iliac at the bottom of the wound, and by 
tracing this vessel upward the internal iliac is arrived at, opposite the sacro-iliac articulation. It 
should be remembered that the vein lies behind and on the right side, a little external to the 
artery, and in close contact with it; the ureter and peritoneum, which lie in front, must also be 
avoided. The degree of facility in applying a ligature to this vessel will mainly depend upon 
the length of the vessel. It has been seen that in the great majority of the cases examined the 
artery was short, varying from an inch to an inch and a half; in these cases the artery is deeply 
seated in the pelvis; when, on the contrary, the vessel is longer, it is found partly above that 
cavity. If the artery is very short, as occasionally happens, it would be preferable to apply a 
ligature to the common iliac or to both the external and internal iliacs at their origin. 
A better method of tying the internal iliac artery is by an abdominal section in the median 
line and reaching the vessel through the peritoneal cavity. This plan has been advocated by 
Dennis, of New York, on the following grounds: (1) It in noway increases the danger of the 
operation; (2) it prevents a series of accidents which have occurred during ligature of the artery 
by the older methods; (3) it enables the surgeon to ascertain the exact extent of disease in the 
main arterial trunk, and select his spot for the application of the ligature; and (4) it occupies 
much less time. 
Collateral Circulation.-In Professor Owen's dissection of a case in which the internal 
iliac artery had been tied by Stevens ten years before death for aneurism of the sciatic artery, 
the internal iliac was found impervious for about an inch above the point where the ligature had 
been applied, but the obliteration did not extend to the origin of the external iliac, as the ilio- 
lumbar artery arose just above this point. Below the point of obliteration the artery resumed 
its natural diameter, and continued so for half an inch, the obturator, lateral sacral, and gluteal 
arising in succession from the latter portion. The obturator artery was entirely obliterated. 
The lateral sacral artery was as large as a crow's quill, and had a very free anastomosis with the 
artery of the opposite side and with the middle sacral artery. The sciatic artery was entirely 
obliterated as far as its point of connection with the aneurismal tumor, but on the distal side of 
the sac it was continued down along the back of the thigh nearly as large in size as the femoral, 
being pervious about an inch below the sac by receiving an anastomosing vessel from the pro- 
funda.1 The circulation was carried on by the anastomoses of the uterine and ovarian arteries; 
of the opposite vesical arteries; of the hemorrhoidal branches of the internal iliac with those 
from the inferior mesenteric; of the obturator artery, by means of its pubic branch, with the 
vessel of the opposite side and with the epigastric and internal circumflex; of the circumflex 
1 Medico-Chirurgical Transactions, vol. xvi. THE BLOOD-VASCULAR SYSTEM 
686 
and perforating branches of the profunda femoris with the sciatic; of the gluteal with the poste- 
rior branches of the sacral arteries; of the ilio-lumbar with the last lumbar; of the lateral sacral 
with the middle sacral; and of the circumflex iliac with the ilio-lumbar and gluteal. 
Branches (Fig. 424).-The branches of the internal iliac are: 
From the Anterior Trunk. 
Superior Vesical. 
Middle Vesical. 
Inferior Vesical. 
Middle HaemorrhoidaL 
Obturator. 
Internal Pudic. 
Sciatic. 
From the Posterior Trunk, 
Uio-lumbar. 
Lateral Sacral. 
Gluteal. 
Uterine. 
Vaginal. 
In female 
The Superior Vesical (a. vesicalis superior) (Fig. 424) is that part of the foetal 
hypogastric artery, which remains pervious after birth. It extends to the side of 
the bladder, distributing numerous branches to the apex and body of the organ. 
From one of these a slender vessel is derived which accompanies the vas deferens 
in its course to the testis, where it anastomoses with the spermatic artery. This is 
the artery of the vas deferens. Other branches supply the ureter. 
Branches to tube. 
Branches to f undus. 
Ovarian artery. 
Branch to round ligament. 
ROUND LIGAMENT. 
Uterine artery. 
Arteries of cervix. 
Uterine artery. 
Vaginal arteries. 
Fig. 425.-The arteries of the internal organs of generation of the female, seen from behind. (After Hyrtl.) 
The Middle Vesical (a. vesicalis medialis} (Fig. 424), usually a branch of the 
superior, is distributed to the base of the bladder and under surface of the vesiculae 
seminales. 
The Inferior Vesical (a. vesicalis inferior} (Fig. 424) arises from the anterior 
division of the internal iliac, frequently in common with the middle hemorrhoidal, 
and is distributed to the base of the bladder, the prostate gland, and vesiculae THE INTERNAL ILIAC ARTERY 
687 
seminales. The branches distributed to the prostate communicate with the 
corresponding vessel of the opposite side. 
'rhe Middle Haemorrhoidal Artery {a. hoemorrhoidalis media) (Fig. 424) 
usually arises together with the preceding vessel. It supplies the anus and 
parts outside the rectum, anastomosing with the other hemorrhoidal arteries. 
The Uterine Artery (a. uterina) (Fig. 425) passes inward from the anterior 
trunk of the internal iliac to the neck of the uterus. Ascending in a tortuous course 
on the side of this viscus, between the layers of the broad ligament, it distributes 
branches to its substance and to the round ligament and the Fallopian tube {ramus 
tubarius), anastomosing, near its termination, with the ovarian artery. It gives a 
branch to the ovary {ramus ovarii), which anastomoses with a branch from the 
ovarian branches to the cervix uteri {cervico-uteri), and a branch which descends 
Fig. 426.-The utero-ovarian artery forming the circle described by Byron Robinson. 
on the vagina (cervico-vaginal), and, joining with branches from the vaginal 
arteries, form a median longitudinal vessel both in front and behind; these 
descend on the anterior and posterior surfaces of the vagina, and are named 
the azygos arteries of the vagina. 
The Vaginal Artery (a. vaginalis) (Fig. 426) is analogous to the inferior vesical 
in the male; it descends upon the vagina, supplying its mucous membrane, and 
sending branches to the neck of the bladder and contiguous part of the rectum. 
There may be several vaginal arteries. The vaginal artery assists in forming the 
azygos arteries of the vagina, which are anterior and posterior vessels, running 
longitudinally, and due to anastomoses of the branches of the vaginal from each 
side and the cervico-vaginal artery. 
Luschka, Hyrtl, Waldeyer, Byron Robinson, and others, instead of describing 
the ovarian and uterine arteries as two distinct vessels, regard them as constituting THE BLOOD-VASCULAR SYSTEM 
688 
the chief parts of one vessel, the arteria uterina ovarica. What has been called " the 
circle of Byron Robinson" is composed of a spiral segment (the arteria uterina 
ovarica), with a portion of the abdominal aorta, common iliacs, and internal iliacs 
(Fig. 426). 
Byron Robinson1 has made a careful study of this vascular circle; he shows 
that it is of great importance in certain surgical procedures, and that its remark- 
able "capacity for extension" saves it from damage when the uterus is enormously 
distended by pregnancy, or when it is " drawn through the pudendum with trac- 
tion forceps for palpation, inspection, or repair." 
The author just quoted says further that the utero-ovarian artery has three 
origins, because it develops from the Wolffian body: The ovarian segment arises 
from the abdominal aorta. The uterine segment arises from the anterior branch 
of the internal iliac artery. The artery of the round ligament arises from the deep 
epigastric. The arteria uterina ovarica artery secures nutrition to the uterus by 
bringing blood from three sources. It is spiral throughout its entire course, in 
certain parts is convoluted or looped, and it is accompanied by the pampiniform 
plexus of veins. 
The three origins of this vessel are freely united by anastomoses, and rami 
laterales are given off, which unite the bilateral vessels in the median line. Robin- 
son describes three bifurcations of the utero-ovarian artery. The distal bifurcation, 
which is "about midway between the uterus and the pelvic wall," and forms an 
acute angle with the main vessel. This bifurcation indicates the point of division 
of the external from the internal genitals. The cervico-vaginal artery supplies the 
external genitals. The proximal bifurcation marks the situation of the ovary. The 
artery bifurcates at an acute angle into two branches to supply the ovary and 
Fallopian tube. The middle bifurcation consists of (1) the division of the uterine 
segment at the angle formed by the uterus and oviduct ("forming the ramus ovi- 
ductus and ramus ovarii") and (2) "the bifurcation of the ramus oviductus form- 
ing the ramus oviductus and the ramus ligamenti teretis, or the segment of the 
round ligament."2 The relations of the utero-ovarian artery and the ureter are 
shown in Fig. 426. 
Surgical Anatomy.-As pointed out by Byron Robinson, the source of bleeding after vaginal 
hysterectomy is usually the torn and unclamped cervico-vaginal artery. 
As previously pointed out, the spiral and convoluted shape of the utero-ovarian artery allows 
the uterus, ovary, and tube to be drawn into the vagina without injury to the vessels. Bryon 
Robinson points out that in vaginal hysterectomy the genital circle is not divided and only the 
rami laterales which go to the uterus are cut, the ovaries retaining a normal blood-supply and 
continuing to functionate. 
The Obturator Artery (a. obturator ia) (Fig. 424) usually arises from the anterior 
trunk of the internal iliac; frequently from the posterior. It passes forward, below 
the brim of the pelvis, to the upper part of the obturator foramen, accompanied by 
the obturator nerve and vein, and, escaping from the pelvic cavity through a short 
canal formed by a groove on the under surface of the ascending ramus of the os 
pubis and the arched border of the obturator membrane, it divides into an internal 
and external branch. In the pelvic cavity this vessel lies upon the pelvic fascia, 
beneath the peritoneum, and a little below the obturator nerve. 
Branches.-Within the pelvis, the obturator artery gives off an iliac branch 
(ramus iliacus) to the iliac fossa, which supplies the bone and the Iliacus muscle, 
and anastomoses with the ilio-lumbar artery; a vesical branch (ramus vesicalis), 
which runs backward to supply the bladder; and a pubic branch (ramus pubicus), 
which is given off from the vessel just before it leaves the pelvic cavity. This 
branch ascends upon the back of the os pubis, communicating with offsets from 
1 The Utero-ovarian Artery. 2 Byron Robinson. The Utero-ovarian Artery. THE INTERNAL ILIAC ARTERY 
689 
the deep epigastric artery and with the corresponding vessel of the opposite 
side. It is placed on the inner side of the femoral ring. External to the pelvis, 
the obturator artery divides into an internal and an external branch, which are 
deeply situated beneath the Obturator externus muscle. 
The Internal Branch (ramus anterior) curves downward along the inner margin 
of the obturator foramen, lying beneath the Obturator externus muscle; it dis- 
tributes branches to the Obturator externus, Pectineus, Adductors, and Gracilis, 
and anastomoses with the external branch and with the internal circumflex artery. 
The External Branch (ramus posterior) curves round the outer margin of the 
obturator foramen, also lying beneath the Obturator externus muscle, to the space 
between the Gemellus inferior and Quadratus femoris, where it divides into two 
branches: one, smaller, courses inward around the lower margin of the foramen 
and anastomoses with the internal branch and with the internal circumflex; the 
other inclines outward in the groove below the acetabulum (a. acetabulis), and 
supplies the muscles attached to the tuberosity of the ischium and anastomoses 
with the sciatic artery. It sends a branch to the hip-joint through the cotyloid 
notch, which ramifies on the round ligament as far as the head of the femur. 
Peculiarities (Fig. 427).-In two out of every three cases the obturator arises from the 
internal iliac; in one case in three and a half from the epigastric; and in about one in seventy- 
two cases by two roots from both vessels. It arises in about the same proportion from the 
external iliac artery. The origin of the obturator from the epigastric is not commonly found 
on both sides of the same body. 
A 
If 
Fig. 427.-Variations in origin and course of the obturator artery. 
When the obturator artery arises at the front of the pelvis from the epigastric, it descends 
almost vertically to the upper part of the obturator foramen. The artery in this course usually 
lies in contact with the external iliac vein and on the outer side of the femoral ring (Fig. 427, A); 
in such cases it would not be endangered in the operation for femoral hernia. Occasionally, 
however, it curves inward along the free margin of Gimbernat's ligament (Fig. 427, B), and 
under such circumstances would almost completely encircle the neck of a hernial sac (supposing 
a hernia to exist in such a case), and would be in great danger of being wounded if an operation 
was performed. 
"The Internal Pudic Artery (a. pudenda interna) (Figs. 424, 428, and 429) is the 
smaller of the two terminal branches of the anterior trunk of the internal iliac, 
and supplies the external organs of generation. Though the course of the artery 
is the same in the two sexes, the vessel is much smaller in the female than in the 
male, and the distribution of its branches somewhat different. The description of 
its arrangement in the male will first be given, and subsequently the differences 
which it presents in the female will be mentioned. 
The Internal Pudic Artery in the Male passes downward and outward to the 
lower border of the great sacro-sciatic foramen, and emerges from the pelvis 
between the Pyriformis and Coccygeus muscles: it then crosses the spine of the 
ischium and re-enters the pelvis through the lesser sacro-sciatic foramen. The 
artery now crosses the Obturator internus muscle along the outer wall of the ischio- 
rectal fossa, being situated about an inch and a half above the lower margin of the 
ischial tuberosity. It is here contained in a sheath of the obturator fascia, and 690 
THE BLOOD-VASCULAR SYSTEM 
gradually approaches the margin of the ramus of the ischium, along which it passes 
forward and upward, pierces the base of the superficial layer of the triangular 
ligament of the urethra, and runs forward along the inner margin of the ramus of 
the os pubis, and divides into its two terminal branches, the dorsal artery of the 
penis and the artery of the corpus cavernosum. 
Relations.-In the first part of its course, within the pelvis, it lies in front of 
the Pyriformis muscle and sacral plexus of nerves, and the sciatic artery, and 
on the outer side of the rectum (on the left side). As it crosses the spine of the 
ischium it is covered by the Gluteus maximus and overlapped by the great sacro- 
sciatic ligament. Here the obturator nerve lies to the inner side and the nerve 
to the Obturator interims to the outer side of the vessel. In the pelvis it lies on 
the outer side of the ischio-rectal fossa, upon the surface of the Obturator internus 
muscle, contained in a fibrous canal, the canal of Alcock, formed by the splitting of 
the obturator fascia. It is accompanied by the pudic veins and the pudic nerve. 
Peculiarities.-The internal pudic is sometimes smaller than usual, or fails to give off one 
or two of its usual branches; in such cases the deficiency is supplied by branches derived from 
an additional vessel, the accessory pudic, which generally arises from the internal pudic artery 
before its exit from the great sacro-sciatic foramen. It passes forward along the lower part of 
the bladder and across the side of the prostate gland to the root of the penis, where it perforates 
the triangular ligament and gives off the branches usually derived from the pudic artery. The 
deficiency most frequently met with is that in which the internal pudic ends as the artery of the 
bulb, the artery of the corpus cavernosum and arteria dorsalis penis being derived from the 
accessory pudic. Or the pudic may terminate as the superficial perineal, the artery of the bulb 
being derived, with the other two branches, from the accessory vessel. Occasionally the acces- 
sory pudic artery is derived from one of the other branches of the internal iliac, most frequently 
the inferior vesical or the obturator. 
Surgical Anatomy.-The relation of the accessory pudic to the prostate gland and urethra 
is of the greatest interest in a surgical point of view, as this vessel is in danger of being wounded 
in the operation of lateral lithotomy. The student should also study the position of the internal 
pudic artery and its branches, when running a normal course with regard to the same operation. 
The superficial and the transverse perineal arteries are, of necessity, divided in this operation, 
but the hemorrhage from these vessels is seldom excessive; should a ligature be required, it 
can readily be applied on account of their superficial position. The artery of the bulb may 
be divided if the incision be carried too far forward, and injury of this vessel may be attended 
with serious or even fatal consequences. The main trunk of the internal pudic artery may be 
wounded if the incision be carried too far outward; but, being bound down by the strong obtura- 
tor fascia and under cover of the ramus of the ischium, the accident is not very likely to occur 
unless the vessel runs an anomalous course. 
Branches.-The branches of the internal pudic artery are-the 
Muscular. 
Inferior H.emorrhoidal. 
Superficial Perineal. 
Transverse Perineal. 
Artery of the Bulb. 
Artery of the Corpus Cavernosum. 
Dorsal Artery of the Penis. 
The Muscular Branches consist of two sets-one given off in the pelvis, the 
other as the vessel crosses the ischial spine. The former are several small offsets 
which supply the Levator ani, the Obturator internus, the Pyriformis, and the 
Coccygeus muscles. The branches given off outside the pelvis are distributed to 
the adjacent part of the Gluteus maximus and External rotator muscles. They 
anastomose with branches of the sciatic artery. 
The Inferior Haemorrhoidal Artery (a. hamorrhoidalis inferior) arises from 
the internal pudic as it passes above the tuberosity of the ischium. Crossing the 
ischio-rectal fossa it is distributed by two or three terminal branches to the 
muscles and integument of the anal region. Instead of one inferior hemor- 
rhoidal artery two or three small vessels may arise from the internal pudic. 
The Superficial Perineal Artery (a. perinei)(Fi^. 428) supplies the scrotum and the 
muscles and integument of the perinaeum. It arises from the internal pudic in front THE INTERNAL ILIAC ARTERY 
691 
of the preceding branches, and turns upward, crossing either over or under the 
Transversus perinei superficialis muscle, and runs forward, parallel to the pubic 
arch, in the interspace between the Accelerator urinse and Erector penis muscles, 
both of which it supplies, and is finally distributed to the skin and dartos of the 
scrotum. In its passage through the perinseuin it lies beneath the superficial 
perineal fascia. 
The Transverse Perineal Artery is a small branch which arises either from the 
internal pudic or from the superficial perineal artery as it crosses the Transversus 
perinsei muscle. It runs transversely inward along the cutaneous surface of the 
Transversus perinei superficialis muscle, which it supplies, as well as the structures 
between the anus and bulb of the urethra, and anastomoses with the like vessel 
of the opposite side. 
Transversus perinei 
superficialis.' 
■Superficial perineal artery. 
GREAT SACRO- 
SCIATIC LIGAMENT. 
■Superficial perineal nerve. 
.Internal pudic nerve. 
Internal pudic artery. 
Fig. 428.-The superficial muscles and vessels of the perinseum. 
The Artery of the Bulb (a. bulbi urethrae) is a large but very short vessel which 
arises from the internal pudic between the two layers of the triangular ligament, 
and, passing nearly transversely inward, between the fibres of the Compressor 
urethrae muscle, it pierces the bulb of the urethra, which it supplies, and con- 
tinues anteriorly in the corpus spongiosum to the glans and anastomoses with its 
fellow of the opposite side. It gives off a small branch which descends to supply 
Cowper's gland. 
Surgical Anatomy.-This artery is of considerable importance in a surgical point of view, 
as it is in danger of being wounded in the median or the lateral operation of lithotomy-an 
accident usually attended in the adult with alarming hemorrhage. The vessel is sometimes 
very small, occasionally wanting, or even double. It sometimes arises from the internal pudic 
earlier than usual, and crosses the perinaeum to reach the back part of the bulb. In such a case 
the vessel could hardly fail to be wounded in the performance of the lateral operation of lith- 
otomy. If, on the contrary, it should arise from an accessory pudic, it lies more forward than 
usual and is out of danger in the operation. 
The Artery of the Corpus Cavernosum (a. profunda penis'), one of the terminal 
branches of the internal pudic, arises from that vessel while it is situated between THE BLOOD-VASCULAR SYSTEM 
692 
the two layers of the triangular ligament; it pierces the superficial layer, and, 
entering the crus penis obliquely, it runs forward in the centre of the corpus 
cavernosum, to which its branches are distributed. 
The Dorsal Artery of the Penis (a. dorsalis penis) ascends between the crus and 
pubic symphysis, and, piercing the triangular ligament, passes between the two 
layers of the suspensory ligament 
of the penis, and runs forward 
on the dorsum of the penis to the 
glans, where it divides into two 
branches which supply the glans 
and prepuce. On the dorsum 
of the penis it lies immediately 
beneath the integument, parallel 
with the dorsal vein and the 
corresponding artery of the op- 
posite side. It supplies the in- 
tegument and fibrous sheath of 
the corpus cavernosum, sending 
branches through the sheath to 
anastomose with the preceding 
vessel. 
The Internal Pudic Artery in 
the Female is smaller than in the 
male. Its origin and course are 
similar, and there is consider- 
able analogy in the distribution 
of its branches. The superficial 
perineal artery supplies the labia 
pudendi; the artery of the bulb 
supplies the bulbi vestibuli and 
the erectile tissue of the vagina; 
the artery of the corpus cav- 
ernosum (a. profunda clitoridis) 
supplies the cavernous body of 
the clitoris; and the arteria 
dorsalis clitoridis supplies the 
dorsum of that organ, and ter- 
minates in the glans and in the 
membranous fold corresponding 
to the prepuce of the male. 
The Sciatic Artery (a. glutcea 
inferior) (Fig. 429), the larger of 
the two terminal branches of the 
anterior trunk of the internal 
iliac, is distributed to the mus- 
cles at the back of the pelvis. 
It passes down to the lower part 
of the great sacro-sciatic fora- 
men behind the internal pudic artery, resting on the sacral plexus of nerves and 
Pyriformis muscle, and escapes from the pelvis through this foramen between the 
Pyriformis and Coccygeus. It then descends in the interval between the tro- 
chanter major and tuberosity of the ischium, accompanied by the sciatic nerves, 
and covered by the Gluteus maximus, and is continued down the back of the thigh 
supplying the skin, and anastomosing with branches of the perforating arteries. 
Termination 
of internal 
circumflex. 
Superior 
perforating 
Middle 
perforating. 
Inferior 
perforating. 
Termination of 
profunda. 
Superior muscular. 
Superior internal 
articular. 
Superior external 
articular. 
Inferior muscular. 
Fig. 429.- The arteries of the gluteal and posterior femoral 
regions. THE INTERNAL ILIAC ARTERY 
693 
Within the pelvis it distributes branches to the Pyriformis, Coccygeus, and 
Levator ani muscles; some hemorrhoidal branches, which supply the rectum, and 
occasionally take the place of the middle hemorrhoidal artery; and vesical 
branches to the base and neck of the bladder, vesiculse seminales, and prostate 
gland. External to the pelvis it gives off the following branches: 
Coccygeal. 
Inferior Gluteal. 
Comes Nervi Ischiadici. 
Muscular. 
Anastomotic. 
Articular. 
The Coccygeal Branch runs inward, pierces the great sacro-sciatic ligament, and 
supplies the Gluteus maximus, the integument, and other structures on the back 
of the coccyx. 
The Inferior Gluteal Branches, three or four in number, supply the Gluteus 
maximus muscle, anastomosing with the gluteal artery in the substance of the 
muscle. 
The Comes Nervi Ischiadici (a. comitans n. ischiadici) is a long, slender vessel 
which accompanies the great sciatic nerve for a short distance; it then penetrates 
it and runs in its substance to the lower part of the thigh. 
The Muscular Branches supply the Gluteus maximus, anastomosing with the 
gluteal artery in the substance of the muscle; the external rotators, anastomosing 
with the internal pudic artery; and the muscles attached to the tuberosity of the 
ischium, anastomosing with the external branch of the obturator and the internal 
circumflex arteries. 
The Anastomotic Artery is directed downward across the external rotators and 
assists in forming the so-called crucial anastomosis by anastomosing with the 
superior perforating and the internal and external circumflex arteries. 
The Articular Branch, generally derived from,the anastomotic, is distributed to 
the capsule of the hip-joint. 
The Ilio-lumbar Artery (a. ilio lumbalis), given off from the posterior trunk 
of the internal iliac, turns upward and outward between the obturator nerve and 
lumbo-sacral cord, to the inner margin of the Psoas muscle, behind which it divides 
into a lumbar and an iliac branch. 
The Lumbar Branch (ramus lumbalis) supplies the Psoas and Quadratus lum- 
borum muscles, anastomosing with the last lumbar artery, and sends a small 
spinal branch (ramus spinalis) through the intervertebral foramen, between the last 
lumbar vertebra and the sacrum, into the spinal canal, to supply the cauda equina. 
The Iliac Branch (ramus iliacus) descends to supply the Iliacus muscle; some 
offsets, running between the muscle and the bone, anastomose with the iliac branch 
of the obturator; one of these enters an oblique canal to supply the diploe, whilst 
others run along the crest of the ilium, distributing branches to the Gluteal and 
Abdominal muscles, and anastomose in their course with the gluteal, circumflex 
iliac, and external circumflex arteries. 
The Lateral Sacral Artery (a. sacralis lateralis) (Fig. 424) runs downward. 
It may be single, but usually there are two on each side, the superior and inferior 
divisions. 
The Superior Division, which is of large size, passes inward, and, after anastomos- 
ing with branches from the middle sacral, enters the first or second anterior sacral 
foramen, gives spinal branches (rami spinalis) to the contents of the sacral canal, 
and, escaping by the corresponding posterior sacral foramen, supplies the skin 
and muscles on the dorsum of the sacrum, anastomosing with the gluteal. 
The Inferior Division passes obliquely across the front of the Pyriformis muscle 
and sacral nerves to the inner side of the anterior sacral foramina, descends on the 
front of the sacrum, and anastomoses over the coccyx with the middle sacral and 
opposite lateral sacral arteries. In its course it gives off spinal branches which THE BLOOD-VASCULAR SYSTEM 
694 
enter the anterior sacral foramina (rami spinales); these, after supplying the con- 
tents of the sacral canal, escape by the posterior sacral foramina, and are dis- 
tributed to the muscles and skin on the dorsal surface of the sacrum, anastomosing 
with the gluteal. 
The Gluteal Artery (a. glutcea superior) (Fig. 429) is the largest branch of 
the internal iliac, and appears to be the continuation of the posterior division of 
that vessel. It is a short thick trunk, which passes out of the pelvis above the 
upper border of the Pyriformis muscle, and immediately divides into a superficial 
and deep branch. Within the pelvis it gives off a few muscular branches to the 
Iliacus, Pyriformis, and Obturator internus, and, just previous to emerging from 
that cavity, a nutrient artery, which enters the ilium. 
The Superficial Branch passes beneath the Gluteus maximus and divides into 
numerous branches, some of which supply that muscle, whilst others perforate its 
tendinous origin, and supply the integument covering the posterior surface of the 
sacrum, anastomosing with the posterior branches of the sacral arteries. 
The Deep Branch runs between the Gluteus medius and minimus, and sub- 
divides into two. Of these, the superior division (ramus superior), continuing the 
original course of the vessel, passes along the upper border of the Gluteus minimus 
to the anterior superior spine of the ilium, anastomosing with the circumflex iliac 
and ascending branches of the external circumflex artery. The inferior division 
(ramus inferior) crosses the Gluteus minimus obliquely to the trochanter major, 
distributing branches to the Glutei muscles, and inosculates with the external 
circumflex artery. Some branches piece the Gluteus minimus to supply the hip- 
joint. 
Surface Marking.-The position of the three main branches of the internal iliac, the 
sciatic, internal pudic, and gluteal, which may occasionally be the object of surgical interference, 
is indicated on the surface in the following way: A line is to be drawn from the posterior supe- 
rior iliac spine to the posterior superior angle of the great trochanter, with the limb slightly 
flexed and rotated inward: the point of emergence of the gluteal artery from the upper part of 
the sciatic notch will correspond with the junction of the upper with the middle third of this 
line. A second line is to be drawn from the same point to the outer part of the tuberosity of 
the ischium; the junction of the lower with the middle third marks the point of emergence of 
the sciatic and pudic arteries from the great sciatic notch. 
Surgical Anatomy.-Any of these three vessels may require ligating for a wound or for 
aneurism, which is generally traumatic. The gluteal artery is ligated by turning the patient 
two-thirds over on his face and making an incision from the posterior superior spine of the ilium 
to the upper and posterior angle of the great trochanter. This must expose the Gluteus maxi- 
mus muscle, and its fibres are to be separated through the whole thickness of the muscle and 
pulled apart with retractors. The contiguous margins of the gluteus medius and Pyriformis 
are now to be separated from each other, and the arterv will be exposed emerging from the 
sciatic notch. In ligation of the sciatic artery, the incision should be made parallel with that 
for ligation of the gluteal, but one inch and a half lower down. After the fibres of the Gluteus 
maximus have been separated, the vessel is to be sought for at the lower border of the Pyri- 
formis; the great sciatic nerve, which lies just above it, forming the chief guide to the artery. 
The internal pudic can be reached through the incision used to reach the sciatic. 
The External Iliac Artery (A. Iliaca Externa) (Fig. 424). 
The external iliac artery is larger in the adult than is the internal iliac. It 
passes obliquely downward and outward along the inner border of the Psoas 
muscle, from the bifurcation of the common iliac to Poupart's ligament, where 
it enters the thigh and becomes the femoral artery. 
Relations.-In front, with the peritoneum, subperitoneal areolar tissue or Aber- 
nethy's fascia, the termination of the ileum on the right side, and the sigmoid flexure 
on the left, and a thin layer of fascia derived from the iliac fascia, which surrounds 
the artery and vein. At its origin it is occasionally crossed by the ureter. The 
spermatic vessels descend for some distance upon it near its termination, and it is THE EXTERNAL ILIAC ARTERY 
695 
crossed in this situation by the genital branch of the genito-crural nerve and the deep 
circumflex iliac vein; the vasdeferens curves down along its inner side. Behind, 
it is in relation with the external iliac vein, which, at Poupart's ligament, lies at 
its inner side; on the left side the vein is altogether internal to the artery. Exter- 
nally, it rests against the Psoas muscle, from which it is separated by the iliac 
fascia. The artery rests upon this muscle, near Poupart's ligament. Numerous 
lymphatic vessels and glands are found lying on the front and inner side of the 
vessel. 
Plan of the Relations of the External Iliac Artery. 
In front. 
Peritoneum, intestines, and fascia. 
Near 
Poupart's 
Ligament. 
Lymphatic vessels and glands. 
Spermatic vessels. 
Genito-crural nerve (genital branch). 
Deep circumflex iliac vein. 
Outer side. 
Psoas magnus. 
Iliac fascia. 
Inner side. 
External iliac vein and vas deferens 
near Poupart's ligament. 
External 
Iliac. 
Behind. 
External iliac vein. 
Psoas magnus. 
Surface Marking.-The surface line indicating the course of the external iliac artery has 
been already given (see page 682). 
Surgical Anatomy.-The application of a ligature to the external iliac may be required in 
cases of aneurism of the femoral artery or for a wound of the artery. This vessel may be 
secured in any part of its course, excepting near its upper end, which is to be avoided on account 
of the proximity of the great stream of blood in the internal iliac, and near its lower end, which 
should also be avoided, on account of the proximity of the deep epigastric and circumflex iliac 
vessels. The patient having been placed in the supine position, an incision should be made, 
commencing below at a point about three-quarters of an inch above Poupart's ligament, and 
a little external to its middle, and running upward and outward, parallel to Poupart's ligament, 
to a point one inch internal and one inch above the anterior superior spine of the ilium. When 
the artery is deeply seated more room will be required, and may be obtained by curving the 
incision from the point last named inward toward the umbilicus for a short distance. Another 
mode of ligating the vessel is the plan advocated by Sir Astley Cooper, by making an incision 
close to Poupart's ligament from about half an inch outside of the external abdominal ring to 
one inch internal to the anterior superior spine of the ilium. This incision, being made in the 
course of the fibres of the aponeurosis of the external oblique, is less likely to be followed by a 
ventral hernia, but there is danger of wounding the epigastric artery, and only the lower end 
of the vessel can be ligated. Abernethy, who first tied this artery, made his incision in the 
course of the vessel. The abdominal muscles and transversalis fascia having been cautiously 
divided, the peritoneum should be separated from the iliac fossa and raised toward the pelvis; 
and on introducing the finger to the bottom of the wound, the artery may be felt pulsating along 
the inner border of the Psoas muscle. The external iliac vein is generally found on the inner 
side of the artery, and must be cautiously separated from it by the finger-nail or handle of the 
knife, and the aneurism needle should be introduced on the inner side, between the artery and 
the vein. 
Ligation of the external iliac artery has recently been performed by a transperitoneal method. 
An incision four inches in length is made in the semilunar line, commencing about an inch 
below' the umbilicus and carried through the abdominal wall into the peritoneal cavity. The 
intestines are then pushed upward and held out of the way by a broad abdominal retractor, and 
an incision is made through the peritoneum at the margin of the pelvis in the course of the artery, 
and the vessel is secured in any part of its course which may seem desirable to the operator. The 
advantages of this operation appear to be that if it is found necessary, the common iliac artery 
can be ligated instead of the external iliac without extension or modification of the incision; 
and secondly, that the vessel can be ligated without in any way interfering with the coverings 
of the sac of an aneurism. Possibly a disadvantage may exist in the greater risk of hernia after 
this method. 696 
THE BLOOD -VASCULAB SYSTEM 
Collateral Circulation.-The principal anastomoses in carrying on the collateral circulation, 
after the application of a ligature to the external iliac, are-the ilio-lumbar with the circumflex 
iliac; the gluteal with the external circumflex; the obturator with the internal circumflex; the 
sciatic with the superior perforating and circumflex branches of the profunda artery; and the 
internal pudic with the external pudic. When the obturator arises from the epigastric it is 
supplied with blood by branches, either from the internal iliac, the lateral sacral, or the internal 
pudic. The epigastric receives its supply from the internal mammary and inferior intercostal 
arteries, and from the internal iliac by the anastomoses of its branches with the obturator. 
In the dissection of a limb eighteen years after the successful ligature of the external iliac 
artery by Sir A. Cooper, the report of which is to be found in Guy's Hospital Reports, vol. 
i. p. 50, the anastomosing branches are described in three sets: An anterior set.-1, a very 
large branch from the ilio-lumbar artery to the circumflex iliac; 2, another branch from the 
ilio-lumbar, joined by one from the obturator, and breaking up into numerous tortuous branches 
to anastomose with the external circumflex; 3, two other branches from the obturator, which 
passed over the brim of the pelvis, communicated with the epigastric, and then broke up into a 
plexus to anastomose with the internal circumflex. An internal set.-Branches given off from 
the obturator, after quitting the pelvis, which ramified among the adductor muscles on the 
inner side of the hip-joint, and joined most freely with branches of the internal circumflex. 
A posterior set.-1, three large branches from the gluteal to the external circumflex; 2, several 
branches from the sciatic around the great sciatic notch to the internal and external circumflex, 
and the perforating branches of the profunda. 
Branches.-Besides several small branches to the Psoas muscle and the neigh- 
boring lymphatic glands, the external iliac gives off two branches of considerable 
size-the deep epigastric and deep circumflex iliac arteries. 
The Internal or Deep Epigastric Artery (a. epigastrica inferior) (Fig. 424) 
arises from the external iliac a few lines above Poupart's ligament. It at first 
descends to reach this ligament, and then ascends obliquely along the inner margin 
of the internal abdominal ring, lying between the transversalis fascia and peri- 
toneum, and, continuing its course upward, it pierces the transversalis fascia, and 
passing over the semilunar fold of Douglas, enters the sheath of the Rectus muscle. 
It then ascends on the posterior surface of the muscle, and finally divides into 
numerous branches which anastomose, above the umbilicus, with the superior 
epigastric branch of the internal mammary and with the inferior intercostal arteries 
(Fig. 410). The deep epigastric artery bears a very important relation to the 
internal abdominal ring as it passes obliquely upward and inward from its origin 
from the external iliac. In this part of its course it lies along the lower and inner 
margin of the ring and beneath the commencement of the spermatic cord. As 
it passes to the inner side of the internal abdominal ring it is crossed by the vas 
deferens in the male and the round ligament in the female. 
Branches.-The branches of this vessel are the following: The cremasteric 
(a. spermatica externa in the male, a. ligamenti teretis uteri in the female), which 
accompanies the spermatic cord, and supplies the Cremaster muscle and other 
coverings of the cord, anastomosing with the spermatic artery in the male, 
and which accompanies the round ligament in the female; a pubic branch 
(ramus puhicus), which runs along Poupart's ligament, and then descends behind 
the os pubis to the inner side of the femoral ring, and anastomoses with offsets 
from the obturator artery; muscular branches, some of which are distributed to the 
abdominal muscles and peritoneum, anastomosing with the lumbar and circum- 
flex iliac arteries; cutaneous branches perforate the tendon of the External oblique, 
and supply the integument, anastomosing with branches of the superficial epi- 
gastric. 
Peculiarities.-The origin of the deep epigastric may take place from any part of the 
external iliac between Poupart's ligament and two inches and a half above it, or it may arise 
below this ligament, from the common femoral or from the deep femoral. 
Union with Branches.-It frequently arises from the external iliac by a common trunk 
with the obturator. Sometimes the epigastric arises from the obturator, the latter vessel being 
furnished by the internal iliac, or the epigastric may be formed by two branches, one derived 
from the external iliac, the other from the internal iliac. THE FEMORAL ARTERY 
697 
Surgical Anatomy.-The deep epigastric artery follows a line drawn from the middle of 
Poupart's ligament toward the umbilicus; but shortly after this line crosses the linea semilunaris 
the direction changes, and the course of the vessel is directly upward in the line of junction of 
the inner third with the outer two-thirds of the Rectus muscle. It has important surgical rela- 
tions, in addition to the fact that it is one of the principal means, through its anastomosis with 
the internal mammary, in establishing the collateral circulation after ligature of either the com- 
mon or external iliac arteries. It lies close to the internal abdominal ring, and is therefore 
internal to an oblique inguinal hernia, but external to a direct inguinal hernia, as the hernia 
emerges from the abdomen. It forms the outer boundary of Hesselbach's triangle. It is in 
close relationship with the spermatic cord, which lies in front of it in the inguinal canal, 
separated only by the transversalis fascia. The vas deferens hooks round its outer side. 
The Deep Circumflex Iliac Artery (a. circumflexa ilium profunda) (Fig. 424) 
arises from the outer side of the external iliac nearly opposite the epigastric artery. 
It ascends obliquely outward behind Poupart's ligament, contained in a fibrous 
sheath formed by the junction of the transversalis and iliac fascife, to the anterior 
superior spinous process of the ilium. It then runs along the inner surface of the 
crest of the ilium to about its middle, where it pierces the Transversalis, and 
runs backward between that muscle and the Internal oblique, to anastomose with 
the ilio-lumbar and gluteal arteries. Opposite the anterior superior spine of the 
ilium it gives off a large branch which ascends between the Internal oblique and 
Transversalis muscles, supplying them, and anastomosing with the lumbar and 
epigastric arteries. It also gives off cutaneous branches. 
ARTERIES OF THE LOWER EXTREMITY. 
The artery which supplies the greater part of the lower extremity is the direct 
continuation of the external iliac. It continues as a single trunk from Poupart's 
ligament to the lower border of the Popliteus muscle, and here divides into two 
branches, the anterior and posterior tibial, an arrangement exactly similar to what 
occuy.s in the upper limb. For convenience of description, the upper part of the 
main trunk is named femoral, the lower part, popliteal. 
THE FEMORAL ARTERY (A. FEMORALIS) (Figs. 430, 431, 432). 
The femoral artery commences immediately behind Poupart's ligament, 
midway between the anterior superior spine of the ilium and the symphysis 
pubis, and, passing down the forepart and inner side of the thigh, terminates 
at the opening in the Adductor magnus, at the junction of the middle with the 
lower third of the thigh, where it becomes the popliteal artery. The vessel, at 
the upper part of the thigh, lies in front of the hip-joint, just on a line with the 
innermost part of the head of the femur; in the lower part of its course it is in close 
relation with the inner side of the shaft of the bone, and between these two parts 
the vessel is some distance from the bone. In the upper third of the thigh it is 
contained in a triangular space called Scarpa's triangle. In the middle third of the 
thigh it is contained in an aponeurotic canal called Hunter's canal. 
Scarpa's Triangle (trigonum femorale).-Scarpa's triangle corresponds to the 
depression seen immediately below the fold of the groin. It is a triangular space, 
the apex of which is directed downward, and the sides formed externally by the 
Sartorius, internally by the inner margin of the Adductor longus, and above by 
Poupart's ligament. The floor of the space is formed from without inward by the 
Iliacus, Psoas, Pectineus (in some cases a small part of the Adductor brevis), and 
the Adductor longus muscles; and it is divided into two nearly equal parts by the 
femoral vessels, which extend from the middle of its base to its apex, the artery 698 
THE BLOOD-VASCULAR SYSTEM 
giving off in this situation its superficial and profunda branches, the vein receiving 
the deep femoral and internal saphenous. On the outer side of the femoral artery 
is the anterior crural nerve dividing into its branches. In the outer corner of the 
space is the external cutaneous nerve. Within the sheath of the artery, and lying 
upon the outer side of the vessel, is the crural branch of the genito-crural nerve. 
At the base of the triangle the vein is to the inner side of the artery; at the apex 
of the triangle it is passing behind the artery. Besides the vessels and nerves, 
this space contains some fat and lymphatics. 
SUPERFICIAL 
EPIGASTRIC 
SUPERFICIAL CIR- 
CUMFLEX ILIAC 
SUPERFICIAL 
EXTERNAL 
PUDIC 
COMMON 
FEMORAL 
DEEP 
EXTERNAL 
PUDIC 
INTERNAL 
CIRCUM FLEX 
EXTERNAL 
CIRCUMFLEX 
FEMORAL 
PROFUN DA 
DESCENDING 
RAMUS OF 
EXTERNAL 
CIRCUMFLEX 
FIRST 
PERFORATING 
SUPERFICIAL 
'femoral 
SECOND 
PERFORATING 
THIRD 
'PERFORATING 
ANASTOMOTICA 
MAGNA 
SUPERIOR INTERNAL 
ARTICU LAR 
■BRANCH OF 
POPLITEAL 
SUPERIOR EXTER- 
NAL ARTICULAR 
BRANCH OF 
POPLITEAL 
Fig. 430.-Scheme of the femoral artery. (Poirier and Charpy.) 
Hunter's Canal or the Adductor Canal (canalis adductorius [Hunteri]).- 
This is the aponeurotic space in the middle third of the thigh, extending from 
the apex of Scarpa's triangle to the femoral opening in the Adductor magnus 
muscle. It is bounded, externally, by the Vastus interims; internally by the 
Adductors longus and magnus muscles; and is covered in by a strong apon- 
eurosis which extends transversely from the Vastus internus across the femoral THE COMMON FEMORAL ARTERY 
699 
vessels to the Adductor longus and magnus; lying on which aponeurosis is the 
Sartorius muscle. It contains the femoral artery and vein enclosed in their own 
sheath of areolar tissue, the vein being behind and on the outer side of the artery, 
and the internal or long saphenous 
nerve lying at first on the outer side 
and then in front of the vessels. 
For convenience of description, 
and also in reference to its surgi- 
cal anatomy, the femoral artery is 
divided into a short trunk, about 
an inch and a half or two inches 
long, which is known as the com- 
mon femoral artery, while the re- 
mainder of the vessel is termed 
the superficial femoral artery, to 
distinguish it from the deep femoral 
(profunda femoris), a large branch 
given off from the common femoral 
at its termination, and which, 
by its derivation, from the parent 
trunk, marks the commencement 
of the superficial femoral artery. 
. Scrotum. 
The Common Femoral Artery 
(Figs. 430, 431, 432). 
The common femoral artery is 
very superficial, being covered by 
the skin and superficial fascia, 
superficial inguinal lymphatic 
glands, the iliac portion of the 
fascia lata, and the prolongation 
downward of the transversalis 
fascia, which forms the anterior 
part of the sheath of the vessels. 
It has in front of it filaments from 
the crural branch of the genito- 
crural nerve, the superficial cir- 
cumflex iliac vein, and occasionally 
the superficial epigastric vein. It 
rests on the inner margin of the 
Psoas muscle, which separates it 
from the capsular ligament of the 
hip-joint, and a little lower on the 
Pectineus muscle ; and crossing 
behind it is the branch to the 
Pectineus from the anterior crural 
nerve. Separating the artery from 
the Pectineus muscles is the pubic portion of the fascia lata and the prolongation 
from the fascia covering the Iliacus muscle, which forms the posterior layer of the 
sheath of the vessels. The anterior crural nerve lies about half an inch to the 
outer side of the common femoral artery, being separated from the artery by a 
small part of the Psoas muscle. To the inner side of the artery is the femoral vein, 
between the margins of the Pectineus and Psoas muscles. The two vessels are 
Long saphenous 
nerve. 
Anastomotica 
magna. 
Superior external 
articular. 
Anastomotica 
magna. 
-Superior internal 
articular. 
Inferior internal 
articular. 
Inferior internal 
articular. 
Anterior tibial 
recurrent. 
Fig. 431.-The femoral artery. 700 
THE BLOOD - VASCULAR SYSTEM 
enclosed in a strong fibrous sheath formed by the proper sheath of the vessels, 
strengthened by fascia (see page 509); the artery and vein are separated, however, 
from one another by a thin fibrous partition. 
Plan of the Relations of the Common Femoral Artery. 
In front. 
Skin and superficial fascia. 
Superficial inguinal glands. 
Iliac portion of fascia lata. 
Prolongation of transversalis fascia. 
Crural branch of genito-crural nerve. 
Superficial circumflex iliac vein. 
Superficial epigastric vein. 
Outer side. 
Small part of Psoas muscle, 
separating the artery from the 
anterior crural nerve. 
Inner side. 
Femoral vein. 
Common 
Femoral 
Artery. 
Behind. 
Prolongation of fascia covering the Iliacus muscle. 
Pubic portion of fascia lata. 
Nerve to Pectineus. 
Psoas muscle. 
Pectineus muscle. 
Capsule of hip-joint. 
The Superficial Femoral Artery (Figs. 430, 431, 432). 
The superficial femoral artery is only superficial where it lies in Scarpa's tri- 
angle. Here it is covered by the skin, superficial and deep fascia, and crossed 
by the internal cutaneous branch of the anterior crural nerve. In Hunter's canal 
it is more deeply seated, being covered by the integument, the superficial and 
deep fascia, the Sartorius and the aponeurotic covering of Hunter's canal. 'The 
internal saphenous nerve crosses the artery from without inward. Behind, the 
artery lies at its upper part on the femoral vein and the profunda artery and 
vein, which separate it from the Pectineus muscle, and lower down on the Adduc- 
tor longus and Adductor magnus muscles. To the outer side is the long saphenous 
nerve and the nerve to the Vastus internus, the Vastus internus muscle, and, 
at its lower part, the femoral vein. To the inner side is the Adductor longus 
above and the Adductor magnus and Sartorius below. 
Plan of the Relations of the Superficial Femoral Artery. 
In front. 
Skin, superficial and deep fascise. 
Internal cutaneous nerve. 
Sartorius. 
Aponeurotic covering of Hunter's canal. 
Internal saphenous nerve. 
Inner side. 
Adductor longus. 
Adductor magnus. 
Sartorius. 
Outer side. 
Long saphenous nerve. 
Nerve to vastus internus. 
Vastus internus. 
Femoral vein (below). 
Superficial 
Femoral 
Artery. 
Behind. 
Femoral vein. 
Profunda artery and vein 
Pectineus muscle. 
Adductor longus. 
Adductor magnus. THE SUPERFICIAL FEMORAL ARTERY 
701 
The femoral vein, at Poupart's ligament, lies close to the inner side of the artery, 
separated from it by a thin fibrous partition; but lower down it is behind it, and 
then to its outer side. 
The internal saphenous nerve is situated on the outer side of the artery, in the 
middle third of the thigh, beneath the aponeurotic covering of Hunter's canal, but 
not usually within the sheath of the vessels. The internal cutaneous nerve passes 
obliquely across the upper part of the sheath of the femoral artery. 
Peculiarities. Double Femoral Reunited.-Several cases are recorded in which the femoral 
artery divided into two trunks below the origin of the profunda, and became reunited near the 
opening of the Adductor magnus so as to form a single popliteal artery. One of them occurred 
in a patient operated upon for popliteal aneurism. 
Change of Position.-A few cases have been recorded in which the femoral artery was 
situated at the back of the thigh, the vessel being continuous above with the internal iliac, escap- 
ing from the pelvis through the great sacro-sciatic foramen, and accompanying the great sciatic 
nerve to the popliteal space, where its division occurred in the usual manner. The external 
iliac in these cases was small, and terminated in the profunda. 
Position of the Vein.-The femoral vein is occasionally placed along the inner side of the 
artery, throughout the entire extent of Scarpa's triangle, or it may be slit so that a large vein is 
placed on each side of the artery for a greater or less extent. 
Origin of the Profunda. -This vessel occasionally arises from the inner side, and, more 
rarely, from the back of the common trunk; but the more important peculiarity, in a surgical 
point of view, is that which relates to the height at which the vessel arises from the femoral. In 
three-fourths of a large number of cases it arose between one or two inches below Poupart's 
ligament; in a few cases the distance was less than an inch; more rarely, opposite the ligament; 
and in one case, above Poupart's ligament, from the external iliac. Occasionally, the distance 
between the origin of the vessel and Poupart's ligament exceeds two inches, and in one case it 
was found to be as much as four inches. 
Surface Marking.-The upper two-thirds of a line drawn from a point midway between 
the anterior superior spine of the ilium and the symphysis pubis to the adductor tubercle on 
the inner condyle of the femur, with the thigh abducted and rotated outward, will indicate the 
course of the femoral artery. 
Surgical Anatomy.-Compression of the femoral artery, which is constantly requisite in 
amputations and other operations on the lower limbs, and also for the cure of popliteal aneurisms, 
is most effectually made immediately below Poupart's ligament. In this situation the artery is 
very superficial, and is merely separated from the ascending ramus of the os pubis by the Psoas 
muscle; so that the surgeon, by means of his thumb or a compressor, may effectually control the 
circulation through it. This vessel may also be compressed in the middle third of the thigh by 
placing a compress over the artery, beneath the tourniquet, and directing the pressure from 
within outward, so as to compress the vessel against the inner side of the shaft of the femur. 
The application of a ligature to the femoral artery may be required in the cases of wound 
or aneurism of the arteries of the leg, of the popliteal or femoral;1 and the vessel may be exposed 
and tied in any part of its course. The great depth of this vessel at its lower part, its close con- 
nection with important structures, and the density of its sheath render the operation in this 
situation one of much greater difficulty than the application of a ligature at its upper part, 
where it is more superficial. 
Ligature of the common femoral artery is usually considered unsafe, on account of the con- 
nection of large branches with it-viz., the deep epigastric and the deep circumflex iliac arising 
just above Poupart's ligament; on account of the number of small branches which arise from 
it in its short course; and on account of the uncertainty of the origin of the profunda femoris, 
which, if it arise high up, would be too close to the ligature for the formation of a firm coagu- 
lum. The profunda sometimes arises higher than the point above mentioned, and rarely between 
two or three inches (in one case four) below Poupart's ligament. It would appear, then, that 
the most favorable situation for the application of a ligature to the femoral is on the superficial 
femoral at the apex of Scarpa's triangle. In order to expose the artery in this situation, an inci- 
sion between three and four inches long should be made in the course of the vessel, the patient 
lying in the recumbent position, with the limb slightly flexed and abducted, and rotated outward. 
A large vein is frequently met with, passing in the course of the artery to join the internal saphe- 
nous vein; this must be avoided, and the fascia lata having been cautiously divided and the 
Sartorius exposed, that muscle must be drawn outward in order to expose fully the sheath of 
the vessels. The finger being introduced into the wound and the pulsation of the artery felt, 
the sheath should be opened on the outer side of the vessel to a sufficient extent to allow of the 
1 Ligation of the femoral artery has been also recommended and performed for elephantiasis of the leg and 
acute inflammation of the knee-joint (Maunder, Clin. Soc. Trans., vol. ii. p. 37).-Ed. of 15th English edition. 702 
THE BLOOD-VASCULAR SYSTEM 
introduction of the ligature, but no farther; otherwise the nutrition of the coats of the vessel 
may be interfered with, or muscular branches which arise from the vessel at irregular intervals 
may be divided. In this part of the operation the long saphenous nerve and the nerve to the 
Vastus internus, which is in close relation with the sheath, should be avoided. The aneurism 
needle must be carefully introduced and kept close to the artery, to avoid the femoral vein, which 
lies behind the vessel in this part of its course. 
To expose the artery in Hunter's canal, an incision should be made between three and four 
inches in length, a finger's breadth internal to the line of the artery, in the middle of the thigh 
-i. e., midway between the groin and the knee. The integument is first divided. The fascia 
lata having been divided, and the outer border of the Sartorius muscle exposed, it should be 
drawn inward, when the strong fascia which is stretched across from the Adductors to the Vastus 
internus will be exposed, and must be freely divided; the sheath of the vessels is now seen, 
and must be opened, and the artery secured by passing the aneurism needle between the vein 
and artery in the direction from without inward. The femoral vein in this situation lies on the 
outer side of the artery and the long saphenous nerve on the anterior and outer side of the 
artery. 
It has been seen that the femoral artery occasionally divides into two trunks below the origin 
of the profunda. If in the operation for tying the femoral two vessels are met with, the surgeon 
should alternately compress each, in order to ascertain which vessel is connected with the 
aneurismal tumor or with the bleeding from the wound, and that one only should be tied which 
controls the pulsation or hemorrhage. If, however, it is necessary to compress both vessels 
before the circulation in the tumor is controlled, both should be tied, as it would be probable that 
they became reunited, as in the instances referred to above. 
In wounds of the femoral artery the question of the mode of treatment is of considerable 
importance. If the wound in the superficial structures is a large one, the injured vessel must 
be exposed and tied; but if the wound is a punctured one and the bleeding has ceased, the ques- 
tion will arise whether to cut down upon the artery or to trust to pressure. Mr. Cripps1 advises 
that if the wound is in the "upper part of the thigh-that is to say, in a position where the 
femoral artery is comparatively superficial-the surgeon may enlarge the opening with a good 
prospect of finding the wounded vessel without an extensive or prolonged operation. If the 
wound be in the lower half of the thigh, owing to the greater depth of the artery and the possi- 
bility of its being the popliteal that is wounded, the search is rendered a far more severe and 
hazardous operation, and it should not be undertaken until a thorough trial of pressure has 
proved ineffectual." 
Great care and attention are necessary for the successful application of pressure. The limb 
should be carefully bandaged from the foot upward to the wound, which is not covered, and then 
onward to the groin. The wound is then dusted with iodoform or boracic powder and a conical 
pad applied over the wound. Rollers the thickness of the index finger are then placed along 
the course of the vessel above and below the wound, and the whole carefully bandaged to a back 
splint with a foot-piece. 
Collateral Circulation.-When the common femoral is tied the main channels for carrying 
on the circulation are the anastomoses of the gluteal and circumflex iliac arteries above with the 
external circumflex below; of the obturator and sciatic above with the internal circumflex below; 
and of the comes nervi ischiadici with the arteries in the ham. 
The principal agents in carrying on the collateral circulation after ligature of the superficial 
femoral artery are, according to Sir A. Cooper, as follows: 
" The arteria profunda formed the new channel for the blood. The first artery sent off 
passed down close to the back of the thigh-bone, and entered the two superior articular branches 
of the popliteal artery. 
"The second new large vessel, arising from the profunda at the same part with the former, 
passed down by the inner side of the Biceps muscle to a branch of the popliteal which was dis- 
tributed to the Gastrocnemius muscle; whilst a third artery, dividing into several branches, 
passed down with the sciatic nerve behind the knee-joint, and some of its branches united them- 
selves with the inferior articular arteries of the popliteal, with some recurrent branches of those 
arteries, with arteries passing to the Gastrocnemii, and, lastly, with the origin of the anterior 
and posterior tibial arteries. 
"It appears, then, that it is those branches of the profunda which accompany the sciatic 
nerve that are the principal supporters of the new circulation."2 
In Porta's work3 (tab. xii., xiii.) is a good representation of the collateral circulation after 
the ligature of the femoral artery. The patient had survived the operation three years. The 
lower part of the artery is at least as large as the upper; about two inches of the vessel appear 
to have been obliterated. The external and internal circumflex arteries are seen anastomosing 
by a great number of branches with the lower branches of the femoral (muscular and anasto- 
' Heath's Dictionary of Practical Surgery, vol. i. p. 525. 2 Med.-Chir. Trans., vol. ii., 1811. 
3 Alterazioni patologiche delle Arterie. THE SUPERFICIAL FEMORAL ARTERY 
703 
motica magna) and with the articular branches of the popliteal. The branches from the external 
circumflex are extremely large and numerous. One very distinct anastomosis can be traced 
between this artery on the outside and the anastomotica magna on the inside through the inter- 
vention of the superior external articular artery, with which they both anastomose; and blood 
reaches even the anterior tibial recurrent from the external circumflex by means of anastomosis 
with the same external articular artery. The perforating branches of the profunda are also 
seen bringing blood round the obliterated portion of the artery into long branches (muscular) 
External iliac artery. 
Deep epigastric artery. 
Spermatic cord. 
Superior 
circumflex' 
iliac artery. 
Common femoral. 
Profunda 
femoris. 
External cir- 
cumflex. 
Superficial 
femoral. 
Opening in 
adductor 
magnus. 
Fig. 432.-Femoral artery and its branches. (From a preparation in the Museum of the Royal College of 
Surgeons of England.) 
which have been given off just below that portion. The termination of the profunda itself 
anastomoses most freely with the superior external articular. A long branch of anastomosis 
is also traced down from the internal iliac by means of the comes nervi ischiadici of the sciatic, 
which anastomoses on the popliteal nerves with branches from the popliteal and posterior tibial 
arteries. In this case the anastomosis had been too free, since the pulsation and growth of the 
aneurism recurred, and the patient died after ligature of the external iliac. 
There is an interesting preparation in the Museum of the Royal College of burgeons of a 
limb on which John Hunter had tied the femoral artery fifty years before the patient's death. 704 
THE BLOOD-VASCULAR SYSTEM 
The whole of the superficial femoral and popliteal artery seems to have been obliterated. The 
anastomosis by means of the comes nervi ischiadici, which is shown in Porta's plate, is distinctly 
seen: the external circumflex and the termination of the profunda artery seem to have been the 
chief channels of anastomoses; but the injection has not been a very successful one. 
Branches (Figs. 430, 431, and 432).-The branches of the femoral artery 
are-the 
Superficial Epigastric. 
Superficial Circumflex Iliac. 
Superficial External Pudic. 
Deep External Pudic. 
Profunda Femoris 
Externa] Circumflex. 
Interna] Circumflex. 
Three Perforating. 
Anastomotica Magna. 
Muscular. 
The Superficial Epigastric (a. epigastrica superficialis) arises from the fem- 
oral about half an inch below Poupart's ligament, and, passing through the 
saphenous opening in the fascia lata, ascends on the abdomen, in the superficial 
fascia covering the External oblique muscle, nearly as high as the umbilicus. It 
distributes branches to the superficial inguinal glands, the superficial fascia, and 
the integument, anastomosing with branches of the deep epigastric. 
The Superficial Circumflex Iliac (a. circumflexa ilium superficialis), the 
smallest of the cutaneous branches, arises close to the preceding, and, piercing the 
fascia lata, runs outward, parallel with Poupart's ligament, as far as the crest of 
the ilium, dividing into branches which supply the integument of the groin, the 
superficial fascia, and the superficial inguinal lymphatic glands, anastomosing 
with the deep circumflex iliac and with the gluteal and external circumflex 
arteries. 
The Superficial External Pudic or the Superior Superficial External Pudic 
(a. pudenda externa superficialis) arises from the inner side of the femoral artery, 
close to the preceding vessels, and, after passing through the saphenous opening, 
courses inward, across the spermatic cord or round ligament, to be distributed to 
the integument on the lower part of the abdomen, the penis and scrotum in the 
male, and the labium in the female, anastomosing with branches of the internal 
pudic. 
The Deep External Pudic or the Deep Superficial External Pudic (a. pudenda 
externa profunda), more deeply seated than the preceding, passes inward across 
the Pectineus and Adductor longus muscles, covered by the fascia lata, which it 
pierces at the inner border of the thigh, its branches being distributed, in the male, 
to the integument of the scrotum and perineeum; and in the female to the labium, 
anastomdsing with branches of the superficial perineal artery. 
The Deep Femoral or the Profunda Femoris (a. profunda femoris) (Figs. 430, 
431, and 432) nearly equals the size of the superficial femoral. It arises from the 
outer and back part of the femoral artery, from one to two inches below Poupart's 
ligament. It at first lies on the outer side of the superficial femoral, and then 
passes behind it and the femoral vein to the inner side of the femur, and, passing 
downward beneath the Adductor longus, terminates at the lower third of the thigh 
in a small branch which pierces the Adductor magnus (and from this circum- 
stance is sometimes called the fourth perforating artery), and is distributed to the 
flexor muscles on the back of the thigh, anastomosing with branches of the 
popliteal and inferior perforating arteries. 
Relations.-Behind, it lies first upon the Iliacus, and then on the Pectineus, 
Adductor brevis, and Adductor magnus muscles. In front, it is separated from 
the superficial femoral artery, above by the femoral and profunda veins, and 
below by the Adductor longus. On its outer side the origin of the Vastus interims 
separates it from the femur. THE SUPERFICIAL FEMORAL ARTERY 
705 
Plan of the Relations of the Profunda Artery. 
In front. 
Superficial femoral artery. 
Femoral and profunda veins. 
Adductor longus. 
Outer side. 
Vastus interims. 
Profunda 
Femoris. 
Behind. 
Iliacus. 
Pectineus. 
Adductor brevis. 
Adductor magnus. 
Branches.-The profunda gives off the following named branches: 
Muscular. 
External circumflex. 
Internal circumflex. 
Four perforating. 
Muscular Branches are given off in Scarpa's triangle, and also from the vessel as 
it lies between the Adductor muscles. 
'The External Circumflex Artery (a. circumflexa femoris lateralis) supplies the 
muscles on the front of the thigh. It arises from the outer side of the profunda, 
passes horizontally outward, between the divisions of the anterior crural nerve and 
behind the Sartorius and Rectus muscles, and divides into three sets of branches- 
ascending, transverse, and descending. 
The ascending branch (ramus ascendens) passes upward, beneath the Tensor 
fasciae femoris muscle, to the outer side of the hip, anastomosing with the terminal 
branches' of the gluteal and deep circumflex iliac arteries. It sends out muscular 
branches. The descending branch (ramus descendens) passes downward, behind 
the Rectus, upon the Vasti muscles, to which its branches are distributed, one 
or two passing beneath the Vastus externus as far as the knee, anastomosing with 
the superior articular branches of the popliteal artery. These are accompanied by 
the branch of the anterior crural nerve to the Vastus externus. The transverse 
branch, the smallest, passes outward over the Crureus, pierces the Vastus externus, 
and winds round the femur to its back part, just below the great trochanter, 
anastomosing at the back of the thigh with the internal circumflex, sciatic, and 
superior perforating arteries. 
The Internal Circumflex Artery (a. circumflexa femoris medialis), smaller than 
the external, arises from the inner and back part of the profunda, and winds 
round the inner side of the femur, between the Pectineus and Psoas muscles. On 
reaching the upper border of the Adductor brevis it gives off two muscular branches, 
one of which passes inward to be distributed to the Adductor muscles, the Gracilis, 
and Obturator externus, anastomosing with the obturator artery; the other 
descends, and passes beneath the Adductor brevis, to supply it and the great 
Adductor; while the continuation of the vessel passes backward and divides into 
an ascending and a transverse branch (Fig. 348). The ascending branch (ramus 
profundus) passes obliquely upward upon the tendon of the Obturator externus 
and under cover of the Quadratus femoris toward the digital fossa, where it 
anastomoses with twigs from the gluteal and sciatic arteries. The transverse 
branch (ramus superflcialis), larger than the ascending, appears between the 
Quadratus femoris and upper border of the Adductor magnus, anastomosing with 
the sciatic, external circumflex, and superior perforating arteries, the crucial anas- 706 
THE BLOOD-VASCULAR SYSTEM 
tomosis. Opposite the hip-joint the artery gives off an articular vessel (ramus 
acetabuli), which enters the joint beneath the transverse ligament; and, after sup- 
plying the adipose tissue, passes along the round ligament to the head of the bone. 
The Perforating Arteries (Figs. 429, 430, and 431), usually three in number, are 
so called from their perforating the tendon of the Adductor magnus muscle to 
Internal 
saphenous, 
vein. 
Femoral 
artery. 
Anasto- 
motica 
magna. 
Long 
saphenous 
nerve. 
Popliteal, 
artery. 
Long 
saphenous 
nerve. 
Fig. 433.-Side view of the popliteal artery. (From a preparation in the Museum of the Royal College of 
Surgeons of England.) 
reach the back of the thigh. They pass backward close to the linea aspera of the 
femur, under cover of small tendinous arches in the Adductor magnus. The 
first is given off above the Adductor brevis, the second in front of that muscle, 
and the third immediately below it. 
The first perforating artery (a. perjorans primal passes backward between the 
Pectineus and Adductor brevis (sometimes perforates the latter); it then pierces THE POPLITEAL SPACE 
707 
the Adductor magnus close to the linea aspera. It gives off branches which supply 
the Adductor brevis, the Adductor magnus, the Biceps, and Gluteus maximus 
muscles, and anastomoses with the sciatic, internal and external circumflex, and 
middle perforating arteries. The second perforating artery (a. perforans secunda), 
larger than the first, pierces the tendons of the Adductor brevis and Adductor 
magnus muscles, and divides into ascending and descending branches, which 
supply the flexor muscles of the thigh, anastomosing with the first and third 
perforating arteries. The second artery frequently arises in common with the first. 
The nutrient artery of the femur is usually given off from this branch. The third 
perforating artery (a. perforans tertia) is given off below the Adductor brevis; it 
pierces the Adductor magnus, and divides into branches which supply the flexor 
muscles of the thigh; anastomosing above with the higher perforating arteries, and 
below with the terminal branches of the profunda and the muscular branches of 
the popliteal. A fourth perforating artery is represented by the termination of the 
profunda femoris artery. 
'fhe nutritive artery of the femur (a. nutricia femoris), if single, comes from the 
second perforating artery; if double, from the first and third perforating arteries. 
If double, one vessel is called superior and the other inferior. 
Muscular Branches (rami musculares) are given off from the superficial femoral 
throughout its entire course. They vary from two to seven in number, and supply 
chiefly the Sartorius and Vastus internus. 
The Anastomotica Magna (a. genu suprema) (Figs. 430,431, and 433) arises 
from the femoral artery just before it passes through the tendinous opening in the 
Adductor magnus muscle, and immediately divides into a superficial and deep branch. 
The Superficial Branch (ramus saphenous) pierces the aponeurotic covering of 
Hunter's canal, and accompanies the long saphenous nerve to the inner side of the 
thigh. It passes between the Sartorius and Gracilis muscles, and, piercing the fascia 
lata, is distributed to the integument of the upper and inner part of the leg, anasto- 
mosing with the inferior internal articidar artery. 
'rhe Deep Branch (ramus musculoarticularis) descends in the substance of the 
Vastus internus, lying in front of the tendon of the Adductor magnus, to the inner 
side of the knee, where it anastomoses with the superior internal articular artery 
and the anterior recurrent branch of the anterior tibial. A branch from this vessel 
crosses outward above the articular surface of the femur, forming an anastomotic 
arch with the superior external articular artery, and supplies branches to the 
knee-joint. 
THE POPLITEAL ARTERY (A. POPLITEA) (Figs. 429, 430, 433) 
The popliteal artery commences at the termination of the femoral at the 
opening in the Adductor magnus, and, passing obliquely downward and out- 
ward behind the knee-joint to the lower border of the Popliteus muscle divides 
into the anterior and posterior tibial arteries. A portion of the artery lies in the 
popliteal space; but above and below, to a considerable extent, it is covered 
by the muscles which form the boundaries of the space, and is therefore beyond 
the confines of the hollow. 
The Popliteal Space (Fig. 434). 
Dissection.-A vertical incision about eight inches in length should be made along the back 
part of the knee-joint, connected above and below by a transverse incision from the inner to the 
outer side of the limb. The flaps of integument included between these incisions should be 
reflected in the direction shown in Fig. 345, page 522. 
Boundaries.-The popliteal space, or the ham, is a lozenge-shaped space, 
widest at the back part of the knee-joint, and deepest above the articular end of THE BLOOD-VASCULAR SYSTEM 
708 
the femur. It is bounded externally, above the joint, by the Biceps, and below 
the joint by the Plantaris and external head of the Gastrocnemius. Internally, 
above the joint, by the Semimembranosus, Semitendinosus, Gracilis, and Sartorius; 
below the joint, by the inner head of the 
Gastrocnemius. 
Above, it is limited by the apposition of the 
inner and outer hamstring muscles; below, by 
the junction of the two heads of the Gastroc- 
nemius. The floor is formed by the lower 
part of the posterior surface of the shaft of 
the femur, the posterior ligament of the knee- 
joint, the upper end of the tibia, and the 
fascia covering the Popliteus muscle, and the 
space is covered in by the fascia lata. 
Contents.-It contains the popliteal vessels 
and their branches, together with the termina- 
tion of the external saphenous vein, the in- 
ternal and external popliteal nerves and some 
of their branches, the lower extremity of the 
small sciatic nerve, the articular branch from 
the obturator nerve, a few small lymphatic 
glands, and a considerable quantity of loose 
adipose tissue. 
Position of Contained Parts.-The in- 
ternal popliteal nerve descends in the middle 
line of the space lying superficial and cross- 
ing the artery from without inward. The 
external popliteal nerve descends on the outer 
side of the upper part of the space, lying 
close to the tendon of the Biceps muscle. 
More deeply at the bottom of the space are 
the popliteal vessels, the vein lying superficial 
to the artery, to which it is closely united by 
dense areolar tissue ; it is a thick-walled 
vessel, and lies at first to the outer side of the 
artery, and then crosses it to gain the inner 
side below; sometimes the vein is double, the 
artery lying between the two vena1 comites, 
which are usually connected by short trans- 
verse branches. More deeply and, at its 
upper part, close to the surface of the bone 
is the popliteal artery, and passing off from 
it at right angles are its articular branches. 
The articular branch from the obturator 
nerve descends upon the popliteal artery to 
supply the knee, and occasionally there is 
found deep in the space an articular filament 
from the great sciatic nerve. 
The popliteal lymphatic glands, four or 
five in number, are found surrounding the 
artery ; one usually lies superficial to the 
vessel ; another is situated between it and 
the bone, and the rest are placed on either 
side of it. 
Sural arteries 
Anterior peroneal. 
Internal calcanean. 
Fig. 434.-The popliteal, posterior tibial, and 
peroneal arteries. THE POPLITEAL SPACE 
709 
The Popliteal Artery, in its course downward from the aperture in the Adductor 
magnus to the lower border of the Popliteus muscle, rests first on the inner surface 
of the femur, and is then separated by a little fat from the hollowed popliteal 
surface of the bone; in the middle of its course it rests on the posterior ligament 
of the knee-joint, and below on the fascia covering the Popliteus muscle. Super- 
ficially, it is covered above by the Semimembranosus; in the middle of its course, 
by a quantity of fat, which separates it from the deep fascia and integument; and 
below it is overlapped by the Gastrocnemius, Plantaris, and Soleus muscles, the 
popliteal vein, and the internal popliteal nerve. The popliteal vein, which is 
intimately attached to the artery, lies superficial and external to it above; it then 
crosses it and lies to its inner side. The internal popliteal nerve is still more 
superficial and external above, but below the joint it crosses the artery and lies 
on its inner side. Laterally, the artery is bounded by the muscles which are 
situated on either side of the popliteal space. 
Plan of the Relations of the Popliteal Artery. 
In front. 
Femur. 
Ligamentum posticum. 
Popliteus. 
Outer side. 
Biceps. 
Outer condyle. 
Gastrocnemius (outer head). 
Plantaris. 
Inner side 
Semimembranosus. 
Internal condyle. 
Gastrocnemius (inner head). 
Popliteal 
Artery. 
Behind. 
Semimembranosus. 
Fascia. 
Popliteal vein. 
Internal popliteal nerve. 
Gastrocnemius. 
Plantaris. 
Soleus. 
Peculiarities in Point of Division.-Occasionally the popliteal artery divides prematurely 
into its terminal branches; this unusual division occurs most frequently opposite the knee-joint. 
The anterior tibial under these circumstances may pass in front of the Popliteus muscle. 
Unusual Branches.-The artery sometimes divides into the anterior tibial and peroneal, the 
posterior tibial being wanting or very small. Occasionally the popliteal is found to divide into 
three branches, the anterior and posterior tibial and peroneal. 
Surface Marking.-The course of the upper part of the popliteal artery is indicated by 
a line drawn from the outer border of the Semimembranosus muscle at the junction of the 
middle and lower third of the thigh obliquely downward to the middle of the popliteal space, 
exactly behind the knee-joint. From this point it passes vertically downward to the level of a 
line drawn through the lower part of the tubercle of the tibia. 
Surgical Anatomy.-The popliteal artery is not infrequently the seat of injury. It may be 
torn by direct violence, as by the passage of a cart-wheel over the knee or by hyper-extension of 
the knee; and in the dead body, at all events, the middle and internal coats may be ruptured by 
extreme flexion. It may also be lacerated by fracture of the lower part of the shaft of the 
femur or by antero-posterior dislocation of the knee-joint. It has been torn in breaking down 
adhesions in cases of fibrous ankylosis of the knee, and is in danger of being wounded, and in 
fact has been wounded, in performing Macewen's operation of osteotomy of the lower end of the 
femur for genu valgum. In addition, Spencer records a case in which the popliteal artery was 
wounded from in front by a stab just below the knee, the knife passing through the interosseous 
space. The popliteal artery is more frequently the seat of aneurism than is any other artery 
in the body, with the exception of the thoracic aorta. This is due no doubt, in a great measure, 
to the amount of movement to which it is subjected, and to the fact that it is supported by loose 
and lax tissue only, and not by muscles, as is the case with most arteries. 
Ligature of the popliteal artery is required in cases of wound of that vessel, but for aneurism 
of the posterior tibial it is preferable to tie the superficial femoral. The popliteal may be tied 
in the upper or lower part of its course; but in the middle of the ham the operation is attended 710 
THE BLOOD-VASCULAR SYSTEM 
with considerable difficulty, from the great depth of the artery and from the extreme degree of 
tension of the lateral boundaries of the space. 
In order to expose the vessel in the upper part of its course, the patient should be placed 
in the supine position, with the knee flexed and the thigh rotated outward, so that it rests on 
its outer surface; an incision three inches in length, beginning at the junction of the middle 
and lower third of the thigh, is to be made parallel to and immediately behind the tendon of 
the Adductor magnus, and the skin, superficial and deep fascia divided The tendon of the 
muscle is thus exposed, and is to be drawn forward and the hamstring tendons backward. A 
quantity of fatty tissue will now be opened up, in which the artery will be felt pulsating. This 
is to be separated with the point of a director until the artery is exposed. The vein and nerve 
will not be seen, as they lie to the outer side of the artery. The sheath is to be opened and 
the aneurism needle passed from before backward, keeping its point close to the artery for fear 
of injuring the vein. The only structure to avoid is the long saphenous vein in the superficial 
incision. The upper part of the popliteal artery may also be tied by an incision on the back of 
the limb, along the outer margin of the Semimembranosus, but the operation is a more difficult 
one, as the internal popliteal nerve and the popliteal vein are first exposed, and great care has 
to be exercised in separating them from the artery. 
To expose the vessel in the lower part of its course, where the artery lies between the two 
heads of the Gastrocnemius, the patient should be placed in the prone position with the limb 
extended. An incision should then be made through the integument in the middle line, com- 
mencing opposite the bend of the knee-joint, care being taken to avoid the external saphenous 
vein and nerve. After dividing the deep fascia and separating some dense cellular membrane, 
the artery, vein, and nerve will be exposed, descending between the two heads of the Gastrocne- 
mius. Some muscular branches of the popliteal should be avoided if possible, or, if divided, 
tied immediately. The leg being now flexed, in order the more effectually to separate the two 
heads of the Gastrocnemius, the nerve should be drawn inward and the vein outward, and the 
aneurism needle passed between the artery and vein from without inward. 
Branches.-The branches of the popliteal artery are-the 
Superior. 
T F . o , 
Interior or Sural. 
Superior External Articular. 
Azygos Articular. 
Inferior Internal Articular. 
Inferior External Articular. 
Muscular 
Cutaneous. 
Superior Internal Articular/ 
The Superior Muscular Branches, two or three in number, arise from the 
upper part of the popliteal artery, and are distributed to the lower part of the 
Adductor magnus and flexor muscles of the thigh, anastomosing with the fourth 
perforating branch of the profunda. 
The Inferior Muscular (aa. surales) are two large branches which are dis- 
tributed to the two heads of the Gastrocnemius and to the Plantaris muscle. They 
arise from the popliteal artery opposite the knee-joint. 
The Cutaneous Branches arise separately from the popliteal artery or from 
some of its branches; they descend between the two heads of the Gastrocnemius 
muscle, and, piercing the deep fascia, are distributed to the integument of the 
calf. One branch usually accompanies the short, or external, saphenous vein, 
the superficial sural artery. 
The Superior Articular Arteries, two in number, arise one on each side of the 
popliteal, and wind round the femur immediately above its condyles to the front 
of the knee-joint. The internal branch (a. genu superior m ed ial is) winds inward 
beneath the hamstring muscles, to which it supplies branches, above the inner 
head of the Gastrocnemius, and, passing beneath the tendon of the Adductor 
magnus, divides into two branches, one of which supplies the Vastus internus, 
inosculating with the anastomotica magna and inferior internal articular; the other 
ramifies close to the surface of the femur, supplying it and the knee-joint, and an- 
astomosing with the superior external articular artery. This branch is frequently 
of small size, a condition which is associated with an increase in the size of the an- 
astomotica magna. The external branch (a. genu superior lateralis) passes above 
the outer condyle, beneath the tendon of the Biceps, and divides into a superficial 
and deep branch: the superficial branch supplies the Vastus externus, and anasto- THE ANTERIOR TIBIAL ARTERY 
711 
moses with the descending branch of the external circumflex and the inferior exter- 
nal articular arteries; the deep branch supplies the lower part of the femur and 
knee-joint, and forms an anastomotic arch across the bone with the anastomotica 
magna and the inferior internal articular arteries. 
The Azygos Articular (a. genu media) is a small branch arising from the pop- 
liteal artery opposite the bend of the knee-joint. It pierces the posterior ligament, 
and supplies the ligaments and synovial membrane in the interior of the articu- 
lation. 
The Inferior Articular Arteries, two in number, arise from the popliteal 
beneath the Gastrocnemius, and wind round the head of the tibia below the joint. 
The internal branch (a. genu inferior medialis) first descends along the upper mar- 
gin of the Popliteus muscle, to which it gives branches; it then passes below the 
inner tuberosity, beneath the internal lateral ligament, at the anterior border of 
which it ascends to the front and inner side of the joint, to supply the head of the 
tibia and the articulation of the knee, anastomosing with the inferior external 
articular and superior internal articular arteries. The external branch (a. genu 
inferior lateralis) passes outward above the head of the fibula, to the front of the 
knee-joint, passing in its course beneath the outer head of the Gastrocnemius, the 
external lateral ligament, and the tendon of the Biceps muscle, and divides into 
branches which anastomose with the inferior internal articular artery, the superior 
external articular artery, and the anterior recurrent branch of the anterior tibial. 
Circumpatellar Anastomosis.-Around and above the patella, and on the con- 
tiguous ends of the femur and tibia, is a large network of vessels, forming a super- 
ficial and a deep plexus. The superficial plexus is situated between the fascia and 
skin round about the patella; the deep plexus, which forms a close network of 
vessels, lies on the surface of the lower end of the femur and upper end of the 
tibia around their articular surfaces, and sends numerous offsets into the interior 
of the joint. The arteries from which this plexus is formed are the two internal and 
two external articular branches of the popliteal, the anastomotica magna, the ter- 
minal branch of the profunda, the descending branch from the external circumflex 
and the anterior recurrent branch of the anterior tibial. 
The Anterior Tibial Artery (A. Tibialis Anterior) (Fig. 435) 
The anterior tibial artery commences at the bifurcation of the popliteal at 
the lower border of the Popliteus muscle, passes forward between the two 
heads of the Tibialis posticus, and through the large oval aperture above the 
upper border of the interosseous membrane to the deep part of the front of the 
leg; it here lies close to the inner side of the neck of the fibula; it then descends on 
the anterior surface of the interosseous membrane, gradually approaching the 
tibia; and at the lower part of the leg lies on this bone, and then on the anterior 
ligament of the ankle to the bend of the ankle-joint, where it lies more superficially, 
and becomes the dorsalis pedis. 
Relations.-In the upper two-thirds of its extent it rests upon the interosseous 
membrane, to which it is connected by delicate fibrous arches thrown across it; 
in the lower third, upon the front of the tibia and the anterior ligament of the 
ankle-joint. In the upper third of its course it lies between the Tibialis anticus 
and Extensor longus digitorum; in the middle third, between the Tibialis anticus 
and Extensor proprius hallucis. At the bend of the ankle it is crossed by the 
tendon of the Extensor proprius hallucis, and lies between it and the innermost 
tendon of the Extensor longus digitorum. It is covered, in the upper two- 
thirds of its course, by the muscles which lie on either side of it and by the 
deep fascia ; in the lower third, by the integument, anterior annular ligament, 
and fascia. THE BLOOD- VASCULAR SYSTEM 
712 
The anterior tibial artery is accompanied by twb veins, venae comites, which 
lie one on each side of the artery; the anterior tibial nerve, coursing round the 
outer side of the neck of the fibula, comes into relation with the outer side of the 
artery shortly after it has passed through the opening in the interosseous mem- 
brane; about the middle of the leg it is placed superficial to it; at the lower part 
of the artery the nerve is generally again on the outer side. 
Plan of the Relations of the Anterior Tibial Artery. 
In front. 
Integument, superficial and deep fasciae. 
Anterior tibial nerve. 
Tibialis anticus (overlaps it in the upper part of the leg). 
Extensor longus digitorum 
Extensor proprius hallucis 
Anterior annular ligament. 
(overlap it slightly). 
Inner side. 
Tibialis anticus. 
Extensor proprius hallucis 
(crosses it at its lower 
part). 
Anterior 
Tibial. 
Outer side. 
Anterior tibial nerve. 
Extensor longus digitorum. 
Extensor proprius hallucis. 
Behind. 
Interosseous membrane. 
Tibia. 
Anterior ligament of ankle-joint. 
Peculiarities in Size.-This vessel may be very small, may be deficient to a greater or less 
extent, or may be entirely wanting, its place being supplied by perforating branches from the 
posterior tibial or by the anterior division of the peroneal artery. 
Course.-The artery occasionally deviates in its course toward the fibular side of the leg, 
regaining its usual position beneath the annular ligament at the front of the ankle. In two 
instances the vessel has been found to approach the surface in the middle of the leg, being covered 
merely by the integument and fascia below that point. 
Surface Marking.-Draw a line from the inner side of the head of the fibula to midway 
between the two malleoli. In this line take a point one inch and a quarter below the head of 
the fibula, and the portion of the line below this point will mark the course of the artery. 
Surgical Anatomy.-The anterior tibial artery may be tied in the upper or lower part of 
the leg. In the upper part the operation is attended with great difficulty, on account of the 
depth of the vessel from the surface. An incision, about four inches in length, should be made 
through the integument, midway between the spine of the tibia and the outer margin of the 
fibula, and the deep fascia exposed. The wound must now be carefully dried, its edges retracted, 
and the white line separating the Tibialis anticus from the Extensor longus digitorum sought 
for. When this has been clearly defined, the deep fascia is to be divided in this line, and the 
Tibialis anticus separated from adjacent muscles with the handle of the scalpel or a director until 
the interosseous membrane is reached. The foot is to be flexed in order to relax the muscles, and 
upon drawing them apart the artery will be found lying on the interosseous membrane with the 
nerve on its outer side or on the top of the artery. The nerve should be drawn outward, and 
the venae comites separated from the artery and the needle passed round it. 
To tie the vessel in the lower third of the leg above the ankle-joint an incision about three 
inches in length should be made through the integument between the tendons of the Tibialis 
anticus and Extensor proprius hallucis muscles, the deep fascia being divided to the same extent. 
The tendon on either side should be held aside, when the vessel will be seen lying upon the 
tibia, with the nerve on the outer side and one of the venae comites on either side. 
Branches.-The branches of the anterior tibial artery are-the 
Posterior Recurrent Tibial. 
Superior Fibular. 
Anterior Recurrent Tibial. 
Muscular. 
Internal Malleolar. 
External Malleolar. THE ANTERIOR TIBIAL ARTER 1 
713 
The Posterior Recurrent Tibial 
(a. recurrens tibialis posterior) is not 
a constant branch, and is given off 
from the anterior tibial before that 
vessel passes through the interosse- 
ous space. It ascends beneath the 
Popliteus muscle, which it supplies, 
and anastomoses with the lower 
articular branches of the popliteal 
artery, giving off an offset to the 
superior tibio-fibular joint. 
The Superior Fibular is some- 
times given off from the anterior 
tibial, sometimes from the posterior 
tibial. It passes outward, round 
the neck of the fibula, through the 
Soleus, which it supplies, and ends 
in the substance of the Peroneus 
longus muscle. 
The Anterior Recurrent Tibial 
(a. recurrens tibialis anterior) arises 
from the anterior tibial as soon as 
that vessel has passed through the 
interosseous space; it ascends in the 
Tibialis anticus muscle, and ramifies 
on the front and sides of the knee- 
joint, anastomosing with the artic- 
ular branches of the popliteal, with 
the anastomotica magna, and the 
external articular branches of the 
popliteal, assisting in the formation 
of the circumpatellar plexus. 
The Muscular Branches are 
numerous ; they are distributed to 
the muscles which lie on each side 
of the vessel, some cutaneous branches 
piercing the deep fascia to supply 
the integument, others passing 
through the interosseous membrane, 
and anastomosing with branches 
of the posterior tibial and peroneal 
arteries. 
The Malleolar Arteries supply 
the ankle-joint. The internal branch 
(a. malleolaris anterior medialis) 
arises about two inches above the 
articulation, and passes beneath the 
tendons of the Extensor proprius 
hallucis and Tibialis anticus to the 
inner ankle, upon which it ramifies, 
anastomosing with branches of the 
posterior tibial and internal plantar arteries and with the internal calcanean 
from the posterior tibial. The external branch (a. malleolaris anterior lateralis) 
passes beneath the tendons of the Extensor longus digitorum and Peroneus 
Inferior 
external • 
articular. 
Inferior internal 
articular. 
Anterior 
tibial 
recurrent 
Anterior peroneal.- 
Internal 
malleolar. 
External 
malleolar. 
Communicating. 
Fig. 435.-Surgical anatomy of the anterior tibial 
and dorsalis pedis arteries. 714 
THE BLOOD-VASCULAR SYSTEM 
tertius, and supplies the outer ankle, anastomosing with the anterior peroneal 
artery and with ascending branches from the tarsal branch of the dorsalis 
pedis. 
The Dorsalis Pedis Artery (A. Dorsalis Pedis) (Figs. 435, 436). 
The dorsalis pedis, the continuation of the anterior tibial, passes forward from 
the bend of the ankle along the tibial side of the foot to the back part of the first 
intermetatarsal space, where it divides into two branches, the dorsalis hallucis and 
communicating. 
INTERNAL 
MALLEOLAR 
ARTERY 
ANTERIOR 
PERONEAL- 
ARTERY 
EXTERNAL 
MALLEOLAR 
ARTERY 
TARSAL, 
ARTERY 
DORSALIS PEDIS 
ARTERY 
METATARSAL 
ARTERY 
COMMUNICATING 
ARTERY 
DORSAL 
INTEROSSEOUS 
DORSALIS 
HALLUCIS 
"ARTERY 
Fig. 436.-Diagram of the arteries of the dorsal surface of the foot. (Poirier and Charpy.) 
Relations.-This vessel, in its course forward, rests upon the astragalus, navic- 
ular, and middle cuneiform bones and the ligaments connecting them, being cov- 
ered by the integument and fascia, anterior annular ligament, and crossed near 
its termination by the innermost tendon of the Extensor brevis digitorum. On 
its tibial side is the tendon of the Extensor proprius hallucis; on its fibular side, 
the innermost tendon of the Extensor longus digitorum, and the termination of 
the anterior tibial nerve. It is accompanied by two veins. THE DORSALIS PEDIS ARTERY 
715 
Plan of the Relations of the Dorsalis Pedis Artery. 
In jront. 
Integument and fascia. 
Anterior annular ligament. 
Innermost tendon of Extensor brevis digitorum. 
Tibial side. 
Extensor proprius hallucis. 
Dorsalis 
Pedis. 
Fibular side. 
Extensor longus digitorum. 
Anterior tibial nerve. 
Behind. 
Astragalus. 
Navicular. 
Middle cuneiform. 
And their ligaments. 
Peculiarities in size.-The dorsal artery of the foot may be larger than usual, to compen- 
sate for a deficient plantar artery; or it may be deficient in its terminal branches to the toes, 
which are then derived from the internal plantar; or its place may be supplied altogether by a 
large anterior peroneal artery. 
Position.-This artery frequently curves outward, lying external to the line between the 
middle of the ankle and the back part of the first interosseous space. 
Surface Marking.-The dorsalis pedis artery is indicated on the surface of the dorsum of 
the foot by a line drawn from the centre of the space between the two malleoli to the back of the 
first intermetatarsal space. 
Surgical Anatomy.-This artery may be tied, by making an incision through the integu- 
ment between two and three inches in length, on the fibular side of the tendon of the Extensor 
proprius hallucis, in the interval between it and the inner border of the short Extensor muscle. 
The incision should not extend farther forward than the back part of the first intermetatarsal 
space, as the artery divides in that situation. The deep fascia being divided to the same extent, 
the artery will be exposed, the nerve lying upon its outer side. 
Branches.-The branches of the dorsalis pedis are-the 
Cutaneous. 
Tarsal. 
Metatarsal-Interosseous. 
Dorsalis Hallucis. 
Communicating. 
Cutaneous Branches go to the skin of the dorsum and inner surface of the 
foot. 
The Tarsal Artery (a. tarsea lateralis) arises from the dorsalis pedis, as that 
vessel crosses the navicidar bone; it passes in an arched direction outward, lying 
upon the tarsal bones, and covered by the Extensor brevis digitorum; it supplies 
that muscle and the articidations of the tarsus, and anastomoses with branches 
from the metatarsal, external malleolar, peroneal, and external plantar arteries. 
The Metatarsal (a. arcuata) arises a little anterior to the preceding; it passes 
outward to the outer part of the foot, over the bases of the metatarsal bones, 
beneath the tendons of the short Extensor, its direction being influenced by its 
point of origin; and it anastomoses with the tarsal and external plantar arteries. 
This vessel gives off three branches, the dorsal interosseous arteries (aa. meta- 
tarsece dorsales), which pass forward upon the three outer Dorsal interossei mus- 
cles, and, in the clefts between the toes, divide into two dorsal collateral branches 
for the adjoining toes (aa. digitales dorsales). At the back part of each inter- 
osseous space these vessels receive the posterior perforating branches from the 
plantar arch, and at the forepart of each interosseous space they are joined by 
the anterior perforating branches from the digital arteries. The outermost 
interosseous artery gives off a branch which supplies the outer side of the little 
toe. 716 
THE BLOOD-VASCULAR SYSTEM 
The Dorsalis Hallucis or the First Dorsal Interosseous (a. dorsalis hallucis') is one 
of the terminal branches of the dorsalis pedis. It runs forward along the outer 
border of the first metatarsal bone, and at the cleft between the first and second 
toes divides into two branches, one of which passes inward, beneath the tendon of 
the Extensor proprius hallucis, and is distributed to the inner border of the great 
toe; the outer branch bifurcates, to supply the adjoining sides of the great and 
second toes. 
The Communicating Artery (ramus plantaris projundus), the other terminal 
branch of the dorsalis pedis, dips down into the sole of the foot, between the two 
heads of the First dorsal interosseous muscle, and inosculates with the termina- 
tion of the external plantar artery, to complete the plantar arch. It here gives 
off its plantar digital branch, which is named the arteria magna hallucis, or the 
princeps hallucis. This artery passes forward along the first interosseous space, 
and, after sending a branch along the inner side of the great toe, bifurcates for 
the supply of the adjacent sides of the great and second toes. 
The Posterior Tibial Artery (A. Tibialis Posterior) (Fig. 434). 
The posterior tibial is an artery of large size, which extends obliquely down- 
ward from the lower border of the Popliteus muscle, along the tibial side of the 
leg, to the fossa between the inner ankle and the heel, where it divides beneath 
the origin of the Abductor hallucis, on a level with a line drawn from the point 
of the internal malleolus to the centre of the convexity of the heel, into the 
internal and external plantar arteries. At its origin it lies opposite the interval 
between the tibia and fibula; as it descends, it approaches the inner side of 
the leg, lying behind the tibia, and, in the lower part of its course, is situated 
midway between the inner malleolus and the tuberosity of the os calcis. 
Relations.-It lies successively upon the Tibialis posticus, the Flexor longus 
digitorum, the tibia, and the back part of the ankle-joint. It is covered by the 
deep transverse fascia, which separates it above from the Gastrocnemius and 
Soleus muscles: at its termination it is covered by the Abductor hallucis muscle. 
In the lower third, where it is more superficial, it is covered only by the integu- 
ment and fascia, and runs parallel with the inner border of the tendo Achillis. 
It is accompanied by two veins and by the posterior tibial nerve, which lies at 
first to the inner side of the artery, but soon crosses it, and is, in the greater part 
of its course, on its outer side. 
Plan of the Relations of the Posterior Tibial Artery. 
In front. 
Tibialis posticus. 
Flexor longus digitorum. 
Tibia. 
Ankle-joint. 
Inner side. 
Posterior tibial nerve, 
upper third. 
Outer side. 
Posterior tibial nerve, 
lower two-thirds. 
Behind. 
Integument and fascia. 
Gastrocnemius. 
Soleus. 
Deep transverse fascia. 
Posterior tibial nerve. 
Abductor hallucis. 
Behind the inner ankle the tendons and blood-vessels are arranged, under 
cover of the internal annular ligament, in the following order, from within out- THE POSTERIOR TIBIAL ARTERY 
717 
ward: First, the tendons of the Tibialis posticus and Flexor longus digitorum, 
lying in the same groove, behind the inner malleolus, the former being the most 
internal. External to these is the posterior tibial artery, having a vein on either 
side: and, still more externally, the posterior tibial nerve. About half an inch 
nearer the heel is the tendon of the Flexor longus hallucis. 
Peculiarities in Size.-The posterior tibial is not unfrequently smaller than usual, or absent, 
its place being supplied by a large peroneal artery which passes inward at the lower end of the 
tibia, and either joins the small tibial artery or continues alone to the sole of the foot. 
Surface Marking.-The course of the posterior tibial artery is indicated by a line drawn from 
a point one inch below the centre of the popliteal space to midway between the tip of the 
internal malleolus and the centre of the convexity of the heel. 
Surgical Anatomy.-The application of a ligature to the posterior tibial may be required 
in cases of wound of the sole of the foot attended with great hemorrhage, when the vessel 
should be tied at the inner ankle. In cases of wound of the posterior tibial it will be necessary 
to enlarge the opening so as to expose the vessel at the wounded point, excepting where the 
vessel is injured by a punctured wound from the front of the leg. In cases of aneurism from 
wound of the artery low down, the vessel should be tied in the middle of the leg. But in aneurism 
of the posterior tibial high up it would be better to tie the femoral artery. 
To tie the posterior tibial artery at the ankle, a semilunar incision, convex backward, should 
be made through the integument, about two inches and a half in length, midway between the 
heel and the inner ankle or a little nearer the latter. The subcutaneous cellular tissue having been 
divided, a strong and dense fascia, the internal annular ligament, is exposed. This ligament is 
continuous above with the deep fascia of the leg, covers the vessels and nerves, and is intimately 
adherent to the sheaths of the tendons. This having been cautiously divided upon a director, 
the sheath of the vessels is exposed, and, being opened, the artery is seen with one of the venae 
comites on each side. The aneurism needle should be passed round the vessel from the heel 
toward the ankle, in order to avoid the posterior tibial nerve, care being at the same time taken 
not to include the venae comites. 
The vessel may also be tied in the lower third of the leg by making an incision, about three 
inches in length, parallel with the inner margin of the tendo Achillis. The internal saphenous 
vein being carefully avoided, the Iwo layers of fascia must be divided upon a director, when the 
artery is exposed along the outer margin of the Flexor longus digitorum, with one of its venae 
comites on either side and the nerve lying external to it. 
To tie the posterior tibial in the middle of the leg is a very difficult operation, on account of 
the great depth of the vessel from the surface. The patient being placed in the recumbent posi- 
tion, the injured limb should rest on its outer side, the knee being partially bent and the foot 
extended, so as to relax the muscles of the calf. An incision about four inches in length should 
then be made through the integument a finger's breadth behind the inner margin of the tibia, 
taking care to avoid the internal saphenous vein. The deep fascia having been divided, the 
margin of the Gastrocnemius is exposed, and must be drawn aside, and the tibial attachment of 
the Soleus divided, a director being previously passed beneath it. The artery may now be 
felt pulsating beneath the deep fascia about an inch from the margin of the tibia. The fascia 
having been divided, and the limb placed in such a position as to relax the muscles of the calf 
as much as possible, the veins should be separated from the artery, and the aneurism needle 
passed round the vessel from without inward, so as to avoid wounding the posterior tibial nerve. 
Branches.-The branches of the posterior tibial artery are-the 
Peroneal. 
Nutrient. 
Muscular. 
Cutaneous. 
Communicating. 
Internal Calcanean. 
Malleolar cutaneous. 
The Peroneal Artery (a. peronaa) (Fig. 434) lies, deeply seated, along the back 
part of the fibular side of the leg. It arises from the posterior tibial about an inch 
below the lower border of the Popliteus muscle, passes obliquely outward to the 
fibula, and then descends along the inner border of that bone, contained in a 
fibrous canal between the Tibialis posticus and the Flexor longus hallucis, or in 
the substance of the latter muscle to the lower third of the leg, where it gives off 
the anterior peroneal. It then passes across the articulation between the tibia and 
fibula to the outer side of the os calcis, where it gives off its terminal branches, the 
external calcanean. 718 
THE BLOOD-VASCULAR SYSTEM 
Relations.-This vessel rests at first upon the Tibialis posticus, and then, for 
the greater part of its course, in a fibrous canal between the origins of the Flexor 
longus hallucis and Tibialis posticus, covered or surrounded by the fibres of the 
Flexor longus hallucis. It is covered, in the upper part of its course, by the Soleus 
and deep transverse fascia; below, by the Flexor longus hallucis. 
Plan of the Relations of the Peroneal Artery. 
In front. 
Tibialis posticus. 
Flexor longus hallucis. 
Outer side. 
Fibula. 
Flexor longus hallucis. 
Inner side. 
Flexor longus hallucis. 
Peroneal 
Artery. 
Behind. 
Soleus. 
Deep transverse fascia. 
Flexor longus hallucis. 
Peculiarities in Origin.-The peroneal artery may arise three inches below the Popliteus, 
or from the posterior tibial high up, or even from the popliteal. 
Its size is more frequently increased than diminished; and then it either reinforces the poste- 
rior tibial by its junction with it, or altogether takes the place of the posterior tibial in the lower 
part of the leg and foot, the latter vessel only existing as a short muscular branch. In those 
rare cases where the peroneal artery is smaller than usual a branch from the posterior tibial 
supplies its place, and a branch from the anterior tibial compensates for the diminished anterior 
peroneal artery. In one case the peroneal artery has been found entirely wanting. 
The anterior peroneal is sometimes enlarged, and takes the place of the dorsal artery of the 
foot. 
Branches.-The branches of the peroneal are-the 
Muscular. 
Nutrient. 
Anterior Peroneal. 
Communicating. 
Posterior Peroneal. 
External Calcanean. 
Muscular Branches.-The peroneal artery in its course gives off branches to the 
Soleus, Tibialis posticus, Flexor longus hallucis, and Peronei muscles. 
The Nutrient Artery (a. nutritia fibulae) supplies the fibula. 
The Anterior Peroneal (ramus perforans) (Fig. 436) pierces the interosseous 
membrane^ about two inches above the outer malleolus, to reach the forepart of 
the leg, and, passing down beneath the Peroneus tertius to the outer ankle, ramifies 
on the front and outer side of the tarsus, anastomosing with the external malleolar 
and tarsal arteries. 
The Communicating (ramus communicans) is given off from the peroneal about 
an inch from its lower end, and, passing inward, joins the communicating branch 
of the posterior tibial. 
The Posterior Peroneal passes down behind the outer ankle to the back of the 
external malleolus, to terminate in branches which ramify on the outer surface 
and back of the os calcis. 
External Calcanean (ramus calcaneus lateralis) are the terminal branches of the 
peroneal artery; they pass to the outer side of the heel, and communicate with the 
external malleolar, and, on the back of the heel, with the internal calcanean 
arteries. 
Cutaneous Branches come from the posterior tibial and supply the skin of 
the inner side and back of the leg. THE POSTERIOR TIBIAL ARTERY 
719 
The Nutrient Artery of the tibia (a. nutricia tibiae) arises from the posterior 
tibial near its origin, and, after supplying a few muscular branches, enters the 
nutrient canal of that bone, which it traverses obliquely from above downward. 
This is the largest nutrient artery of bone in the body. 
The Muscular Branches of the posterior tibial are distributed to the Soleus and 
deep muscles along the back of the leg. 
The Communicating Branch (ramus communicans), to join a similar branch 
of the peroneal, runs transversely across the back of the tibia, about two inches 
above its lower end, passing beneath the Flexor longus hallucis. 
The Malleolar or Internal Malleolar (a. malleolaris posterior medialis) lies 
upon the tibia, sends branches over the inner ankle, and anastomoses with the 
inner malleolar branch of the anterior tibial. 
The Internal Calcanean (rami calcanei mediates) are several large arteries 
which arise from the posterior tibial just before its division: they are distributed 
Communicating 
branch of 
dorsalis pedis. 
Its digital 
branches. 
Fig. 437.-The plantar arteries. Superficial view. 
Fig. 438.-The plantar arteries. Deep view. 
to the fat and integument behind the tendo Achillis and about the heel, and to the 
muscles on the inner side of the sole, anastomosing with the peroneal and internal 
malleolar, and, on the back of the heel, with the external calcanean arteries. 
The Internal Plantar Artery (a. plantaris medialis) (Figs. 437 and 438), much 
smaller than the external, passes forward along the inner side of the foot. It is 
at first situated above1 the Abductor hallucis, and then between it and the Flexor 
brevis digitorum, both of which it supplies. At the base of the first metatarsal 
bone, where it has become much diminished in size, it passes along the inner border 
of the great toe, inosculating with its digital branch. Small superficial digital 
branches accompany the digital branches of the internal plantar nerve and join 
the plantar digital arteries of the three inner spaces. In addition, this vessel gives 
off numerous cutaneous branches. 
1 This refers to the erect position of the body. In the ordinary position for dissection the artery is deeper 
than the muscle. 720 
THE BLOOD-VASCULAR SYSTEM 
The External Plantar Artery (a. plantaris lateralis) (Figs. 437 and 438), much 
larger than the internal, passes oblicpiely outward and forward to the base of the 
fifth metatarsal bone. It then turns obliquely inward to the interval between 
the bases of the first and second metatarsal bones, where it anastomoses with 
the communicating branch from the dorsalis pedis artery, thus completing the 
plantar arch (arcus plantaris) (Fig. 438). As this artery passes outward, it is first 
placed between the os calcis and Abductor hallucis, and then between the Flexor 
brevis digitorum and Flexor accessorius, and as it passes forward to the base of 
the little toe it lies more superficially between the Flexor brevis digitorum and 
Abductor minimi digiti, covered by the deep fascia and integument. The remain- 
ing portion of the vessel is deeply situated: it extends from the base of the meta- 
tarsal bone of the little toe to the back part of the first interosseous space, and 
forms the plantar arch; it is convex forward, lies upon the Interossei muscles 
opposite the tarsal ends of the metatarsal bones, and is covered by the Adductor 
obliquus hallucis, the flexor tendons of the toes, and the Lumbricales. 
Surface Marking.-The course of the internal plantar artery is represented by a line 
drawn from the mid-point between the tip of the internal malleolus and the centre of the con- 
vexity of the heel to the middle of the under surface of the great toe; the external plantar by 
a line from the same point to within a finger's breadth of the tuberosity of the fifth metatarsal 
bone. The plantar arch is indicated by a line drawn from this point-i. e., a finger's breadth 
internal to the tuberosity of the fifth metatarsal bone transversely across the foot to the back of 
the first interosseous space. 
Surgical Anatomy.-Wounds of the plantar arch are always serious, on account of the 
depth of the vessel and the important structures which must be interfered with in an attempt 
to ligate it. They must be treated on similar lines to those of wounds of the palmar arches 
(see page 665). Delorme has shown that the plantar arch may be ligated from the dorsum of the 
foot in almost any part of its course by removing a portion of one of the three middle metatarsal 
bones. 
Branches.-The plantar arch, besides distributing numerous branches to the 
muscles, integument, and fasciae in the sole, gives off the following branches: 
Posterior Perforating. 
Digital. 
The Posterior Perforating (rami perforantes posteriores) are three small branches 
which ascend through the back part of the three outer interosseous spaces, between 
the heads of the Dorsal interossei muscles, and anastomoses with the interosseous 
branches from the metatarsal artery. 
The Digital Branches (aa. metatarseoe plantares) are four in number, and supply 
the three outer toes and half the second toe. It will be remembered that the 
arteria princeps hallucis is the plantar digital branch of the communicating 
arms in the first interosseous space and supplies the adjacent sides of the great 
and little toes. The first digital branch of the plantar arch passes outward 
from the outer side of the plantar arch, and is distributed to the outer side of the 
little toe, passing in its course beneath the Abductor and short Flexor muscles. 
The second, third, and fourth run forward along the interosseous spaces, and on 
arriving at the clefts between the toes divides into collateral digital branches (aa. 
digitales plantares), which supply the adjacent sides of the three outer toes and 
the outer side of the second. At the bifurcation of the toes each digital artery 
sends upward, through the forepart of the corresponding interosseous space, a 
small branch which inosculates with the interosseous branches of the metatarsal 
artery. These are the anterior perforating branches (rami perforantes anterlores). 
From the arrangement already described of the distribution of the vessels to 
the toes it will be seen that both sides of the three outer toes and the outer side 
of the second toe are supplied by branches from the plantar arch; both sides of 
the great toe and the inner side of the second are supplied by the communicating 
branch of the dorsalis pedis. THE VEINS. 
The Veins are the vessels which serve to return the blood from the capillaries 
of the different parts of the body to the heart. They consist of two distinct sets 
of vessels, the pulmonary and systemic veins, and an appendage to the systemic, 
the portal system. 
The Pulmonary Veins are concerned in the circulation in the lungs. Unlike 
other vessels of this kind, they contain arterial blood, which they return from the 
lungs to the left auricle of the heart. The pulmonary veins are four in number. 
Fig. 439.-Valves of a vein. In the lower part 
of the figure is seen the parietal valves; the upper 
part shows the mouth of a vein guarded by a valve. 
(Poirier and Charpy.) 
Fig. 440.--Collateral anastomosis of veins. The arrows 
indicate the direction of the flow of blood (schematic). 
(Poirier and Charpy.) 
The Systemic Veins are concerned in the general circulation; they return the 
venous blood from the body generally to the right auricle of the heart. The sys- 
temic veins are the superior vena cava, the inferior vena cava, and the coronary 
sinus. 
The Portal Vein constitutes the portal system. The portal system is in reality 
an appendage to the systemic venous system. It is confined to the abdominal 
cavity, returning the venous blood from the viscera of digestion, and carrying it 
to the liver by a single trunk of large size, the portal vein or vena portae. This 
vessel ramifies in the substance of the liver and breaks up into a minute network 
721 THE BLOOD-VASCULAR SYSTEM 
722 
of capillaries. These capillaries then re-collect to form the hepatic veins, by 
which the blood is conveyed to the inferior vena cava. 
The veins, like the arteries, are found in nearly every tissue of the body. They 
commence by minute plexuses which receive the blood from the capillaries. The 
branches which have their commencement in these plexuses unite together 
into trunks, and these, in their passage toward the heart, constantly increase in 
size as they receive tributaries or join other veins. The veins are larger and 
altogether more numerous than the arteries; hence the entire capacity of the 
venous system is much greater than that of the arterial, the pulmonary veins 
excepted, which only slightly exceed in capacity the pulmonary arteries. From 
the combined area of the smaller venous branches being greater than the main 
trunks, it results that the venous system represents a cone, the summit of which 
corresponds to the heart, its base to the circumference of the body. In form the 
veins are perfectly cylindrical, like the arteries, their walls being collapsed when 
empty, and the uniformity of their surface being interrupted at intervals by slight 
constrictions, which indicate the existence of valves in their interior (Fig. 439). 
They usually retain, however, about the same calibre as long as they receive no 
branches, but not so uniformly as do the arteries. 
The veins communicate very freely with one another (Fig. 441), especially in 
certain regions of the body, and this communication exists between the larger 
trunks as well as between the smaller 
branches. Thus, in the cavity of the 
cranium and between the veins of the 
neck, where obstruction would be at- 
tended with imminent danger to the 
cerebral venous system, we find that 
the sinuses and larger veins have large 
and very frequent anastomoses (Fig. 
440). The same free communication 
exists between the veins throughout 
the whole extent of the spinal canal, 
and between the veins composing the 
various venous plexuses in the abdo- 
men and pelvis, as the spermatic, 
uterine, vesical, and prostatic. 
Veins have thinner walls than 
arteries, the difference in thickness 
being due to the small amount of 
elastic and muscular tissues which 
the veins contain. The superficial veins usually have thicker coats than the deep 
veins, and the veins of the lower limb are thicker than those of the upper. 
Histology of the Veins.-As previously stated, capillaries enter into venules 
or precapillary veins. The venules empty into larger veins. Vein walls are much 
thinner than arterial walls. A vein has a much thinner media and much less 
elastic tissue than an artery, and a very strongly developed adventitia. The 
intima is a connective-tissue layer containing a small number of elastic fibres 
and lined with endothelium. The media contains some circular muscle fibres 
and some fine elastic fibres. In some veins the media is thoroughly well devel- 
oped (veins of the lower extremities), in others it is practically absent (veins of 
the retina, of the pia mater, of bone, the superior vena cava). The adventitia 
is dense and strong, and is composed of connective-tissue elastic fibres and 
non-striated muscle fibres placed longitudinally. Fig. 442 shows a transverse sec- 
tion of part of the wall of a vein. The vein valves (Fig. 439) are composed 
of intima and contain elastic fibres. The large veins and the veins of medium 
Fig. 441.-The venous circle of Braune (schematic). 
The arrows indicate the direction of the blood current. 
(Poirier and Charpy.) THE PULMONARY VEINS 
723 
size possess vasa vasorum, in the adventitia and to some extent in the media. 
The walls of veins contain vasomotor nerves. " Small blood-vessels are often 
surrounded by lymph capillaries and sometimes by endothelium-lined spaces 
which are in communication with the lymphatic system. These are called peri- 
vascular lymph spaces."1 
The systemic veins are subdivided into three sets: superficial, deep, and sinuses. 
The Superficial or Cutaneous Veins are found between the layers of the super- 
ficial fascia, immediately beneath the integument; they return the blood from 
these structures, and communicate with the deep veins by perforating the deep 
fascia. 
Endothelial and 
z subendothelial 
layers. 
Elastic layer. 
■Middle coat. 
Outer coat. 
Fig. 442.-Transverse section of part of the wall of one of the posterior tibial veins. (After Schafer.) 
The Deep Veins accompany the arteries, and are usually enclosed in the same 
sheath with those vessels. With the smaller arteries-as the radial, ulnar, brachial, 
tibial, and peroneal-they exist generally in pairs, one lying on each side of the 
vessel, and are called vense comites. The larger arteries-as the axillary, sub- 
clavian, popliteal, and femoral-have usually only one accompanying vein. In 
certain organs of the body, however, the deep veins do not accompany the 
arteries; for instance, the veins in the skull and spinal canal, the hepatic veins in 
the liver, and the larger veins returning blood from the osseous tissue. 
Sinuses are venous channels which, in their structure and mode of distribution, 
differ altogether from the veins. They are found only in the interior of the skull, 
and consist of channels formed by a separation of the two layers of the dura mater, 
their outer coat consisting of fibrous tissue, their inner of an endothelial layer 
continuous with the lining membrane of the veins. 
THE PULMONARY VEINS (V. PULMONALES) (Fig. 443). 
The pulmonary veins return the arterial blood from the lungs to the left auricle 
of the heart. They are four in number, two for each lung. The pulmonary veins 
differ from other veins in several respects: 1. They carry arterial instead of 
venous blood. 2. They are destitute of valves. 3. They are only slightly larger 
than the arteries they accompany. 4. They accompany those vessels singly. 
They commence in a capillary network upon the walls of the air-cells, where they 
are continuous with the capillary ramifications of the pulmonary artery, and, 
uniting together, form one vessel for each lobule. These vessels, uniting suc- 
cessively, form a single trunk for each lobe, three for the right and two for the 
left lung. The vein from the middle lobe of the right lung generally unites with 
that from the upper lobe, forming two trunks on each side, which open separately 
into the left auricle. Occasionally they remain separate; there are then three 
1 Histology and Microscopic Anatomy. By Szymonowicz and MacCallum. 724 
THE BLOOD-VASCULAR SYSTEM 
veins on the right side. Not ^infrequently the two left pulmonary veins terminate 
by a common opening. 
Within the lung, the branches of the pulmonary artery are in front, the veins 
behind, and the bronchi between the two. 
At the root of the lung, the veins are in front, the artery in the middle, and the 
bronchus behind. 
ENTRANCE OF 
"VENA AZYGOS 
branch of pul- 
monary ARTERY 
LEFT 
VENTRICLE 
LEFT 
AURICLE 
Fig. 443.-Pulmonary veins, seen in a dorsal view of the heart and lungs. The left lung is pulled to the 
left, and the right lung has been partly cut away to show the ramifications of the air-tubes and blood-vessels. 
(Testut.) 
Within the pericardium, their anterior surface is invested by the serous layer 
of this membrane. The right pulmonary veins pass behind the right auricle and 
ascending aorta and superior vena cava; the left pass in front of the thoracic 
aorta with the left pulmonary artery. 
THE SYSTEMIC VEINS. 
The systemic veins may be arranged into three groups: 1. Those of the head 
and neck, upper extremity, and thorax, which terminate in the superior vena cava. 
2. Those of the lower extremity, abdomen, and pelvis, which terminate in the 
inferior vena cava. 3. The cardiac veins, which open directly into the right auricle 
of the heart. 
VEINS OF THE HEAD AND NECK. 
The veins of the head and neck may be subdivided into three groups: 1. The 
veins of the exterior of the head and face. 2. The veins of the neck. 3. The veins 
of the diploe and interior of the cranium. PA7AW OF THE EXTERIOR OF THE HEAD AND FACE 
725 
Veins of the Exterior of the Head and Face (Fig. 444). 
The veins of the exterior of the head and face are-the 
Frontal. 
Supraorbital. 
Angular. 
Facial. 
Temporal. 
Internal Maxillary. 
Temporo-maxillary. 
Posterior Auricular. 
Occipital. 
The Frontal Vein (v. frontalis) commences on the anterior part of the skull by 
a venous plexus which communicates with the anterior tributaries of the temporal 
vein. The veins converge to form a single trunk, which runs downward near the 
Communicating 
branch with 
ophthalmic vein. 
Frontal 
Angular. 
Anterior 
'facial. 
Common 
■facial 
Anterior division 
of the temporo- 
maxillary. 
■Lingual. 
Laryngeal. 
Superior thyroid. 
Fig. 444.-Veins of the head and neck. 
middle line of the forehead parallel with the vein of the opposite side, and unites 
with it at the root of the nose by a transverse branch called the1 nasal arch (v. naso- 
jrontalis). Occasionally the frontal veins join to form a single trunk, which 726 
THE BLOOD-VASCULAR SYSTEM 
bifurcates at the root of the nose into the two angular veins. At the root of 
the nose the veins diverge and join the supraorbital vein, at the inner angle of 
the orbit, to form the angular vein. 
The Supraorbital Vein (y. supraorbitalis) commences on the forehead, com- 
municating with the anterior temporal vein, and runs downward and inward, 
superficial to the Occipito-frontalis muscle, receiving tributaries from the neigh- 
boring structures, and from the frontal vein of the diploe, and joins the frontal 
vein at the inner angle of the orbit to form the angular vein. 
The Angular Vein (y. angularis), formed by the junction of the frontal and 
supraorbital veins, runs obliquely downward and outward on the side of the root 
of the nose, and receives the veins of the ala nasi on its inner side and the superior 
palpebral veins on its outer side; it moreover communicates with the ophthalmic 
vein, thus establishing an important anastomosis between this vessel and the 
cavernous sinus. Some small veins from the dorsum of the nose terminate in the 
nasal arch. 
The Anterior Facial Vein (y. facialis anterior) commences at the side of the 
root of the nose, being a direct continuation of the angular vein, which is itself 
formed by the union of the frontal vein and the supraorbital vein. It lies behind 
and follows a less tortuous course than the facial artery. It passes obliquely 
downward and outward, beneath the Zygomaticus major and minor muscles, 
descends along the anterior border of the Masseter, crosses over the body of the 
lower jaw, with the facial artery to beneath the angle, and unites with the anterior 
division of the temporo-maxillary vein (y. facialis posterior) to form the common 
facial vein. 
The Common Facial Vein (y. facialis communis) is formed by the union of the 
anterior facial and the anterior division of the temporo-maxillary vein, just beneath 
the angle of the mandible. The vein is covered by the Platysma myoid muscle, 
runs downward and backward beneath the Sterno-cleido-mastoid muscle, crosses 
the external carotid artery, and empties into the internal jugular vein at the level 
of the hyoid line. It receives a large branch at the anterior border of the Sterno- 
cleido-mastoid muscle, which comes from the anterior jugular vein in the supra- 
sternal fossa. 
Tributaries of the Anterior and Common Facial Veins.-The anterior facial vein 
receives, near the angle of the mouth, communicating tributaries of considerable 
size, the deep facial or anterior internal maxillary vein, from the pterygoid 
plexus. It is also joined by the inferior palpebral, the superior and inferior 
labial veins, the buccal veins from the cheek, and the masseteric veins. The 
common facial vein receives the submental; the inferior palatine, which returns 
the blood from the plexus round the tonsil and soft palate; the submaxillary 
vein, which commences in the submaxillary gland; and, generally, the ranine 
vein. 
Surgical Anatomy.-There are some points about the facial vein which render it of great 
importance in surgery. It is not so flaccid as are most superficial veins, and, in consequence of 
this, remains more patent when divided. It has, moreover, no valves. It communicates freely 
with the intracranial circulation, not only at its commencement by its tributaries, the angular 
and supraorbital veins, communicating with the ophthalmic vein, a tributary of the cavernous 
sinus, but also by its deep branch, which communicates through the pterygoid plexus with the 
cavernous sinus by branches which pass through the foramen ovale and foramen lacerum 
medium. These facts have an important bearing upon the surgery of some diseases of the 
face, for on account of its patency the facial vein favors septic absorption, and therefore any 
phlegmonous inflammation of the face following a poisoned wound is liable to set up thrombosis 
in the facial vein, and detached portions of the clot may give rise to purulent foci in other 
parts of the body. And on account of its communications with the cerebral sinuses these 
thrombi are apt to extend upward into them and so induce a fatal issue. VEINS OF THE EXTERIOR OF THE HEAD AND FACE 
727 
The Superficial Temporal Vein (vv. temporales superficiales) commences by a 
minute plexus on the side and vertex of the skull, which communicates with the 
frontal and supraorbital veins in front, the corresponding vein of the opposite 
side, and the posterior auricular and occipital veins behind. From this network 
anterior and posterior branches are formed which unite above the zygoma, form- 
ing the trunk of the vein. The trunk is joined in this situation by a large vein, 
the middle temporal (v. temporalis media), which receives blood from the sub- 
stance of the Temporal muscle and pierces the fascia at the upper border of 
the zygoma. The junction of the superficial temporal and the middle temporal 
veins forms the common temporal vein (v. temporalis communis), which descends 
between the external auditory meatus and the condyle of the jaw, enters the 
substance of the parotid gland, and unites with the internal maxillary vein to form 
the temporo-maxillary vein. 
Tributaries.-The common temporal vein receives in its course some parotid 
veins, an articular branch from the articulation of the jaw, anterior auricular veins 
from the external ear, and a vein of large size, the transverse facial (v. transversa 
faciei), from the side of the face. The middle temporal vein, previous to its junc- 
tion with the temporal vein, receives a branch, the orbital vein (v. orbitalis), which 
is formed by some external palpebral branches, and passes backward between 
the layers of the temporal fascia. 
The Pterygoid Plexus (plexus pterygoideus) and the Internal Maxillary 
Vein.-The internal maxillary vein is a vessel of considerable size, receiving 
branches which correspond with those of the internal maxillary artery. Thus it 
receives the two middle meningeal veins, the deep temporal, the pterygoid, mas- 
seteric, buccal, and alveolar veins, some palatine veins, the spheno-palatine and the 
inferior dental veins. The deep temporal veins (vv. temporales projundoe) come to 
the pterygoid plexus from the temporal muscle. These branches form a large 
plexus, the pterygoid plexus, which is placed between the Temporal and External 
pterygoid and partly between the Pterygoid muscles. This plexus is a tributary 
of the internal maxillary vein, and communicates very freely with the facial vein 
and with the cavernous sinus by branches through the foramen Vesalii, foramen 
ovale, and foramen lacerum medium, at the base of the skull. The trunk of 
the internal maxillary vein comes from the plexus, then passes backward behind 
the neck of the lower jaw, and unites with the temporal vein, forming the 
temporo-maxillary vein. 
The Temporo-maxillary Vein (v. facialis posterior), formed by the union of 
the superficial temporal and internal maxillary veins, descends in the substance of 
the parotid gland on the outer surface of the external carotid artery, between the 
ramus of the jaw and the Sterno-mastoid muscle, and divides into two branches, 
an anterior, which passes inward to join the facial vein, and a posterior, which 
is joined by the posterior auricular vein and becomes the external jugular. 
The Posterior Auricular Vein (v. auricularis posterior) commences upon the 
side of the head by a plexus which communicates with the tributaries of the tem- 
poral and occipital veins. The vein descends behind the external ear and joins 
the posterior division of the temporo-maxillary vein, forming the external jugular. 
This vessel receives the stylo-mastoid vein and some tributaries from the back 
part of the external ear. 
The Occipital Vein (v. occipitalis) commences at the back part of the vertex 
of the skull by a plexus in a similar manner to the other veins. From the plexus 
comes one or two veins, which follow the course of the occipital artery, passing 
deeply beneath the muscles of the back part of the neck, and terminating in the 
suboccipital triangle by becoming continuous with the posterior vertebral vein. 
Sometimes they are more superficial, and in this case they are tributaries of the THE BLOOD-VASCULAR SYSTEM 
728 
external jugular vein. As the outermost occipital vein passes across the mastoid 
portion of the temporal bone, it receives the mastoid vein, which thus establishes 
a communication with the lateral sinus. 
The Veins of the Neck (Fig. 444). 
The veins of the neck, which return the blood from the head and face, are-the 
External Jugular. 
Posterior External Jugular. 
Anterior Jugular. 
Internal Jugular. 
Vertebral. 
The External Jugular Vein (y. jugularis externa) receives the greater part 
of the blood from the exterior of the cranium and deep parts of the face, being 
formed by the junction of the posterior division of the tempo ro-maxillary and 
the posterior auricular veins. It commences in the substance of the parotid gland, 
on a level with the angle of the lower jaw, and runs perpendicularly down the neck 
in the direction of a line drawn from the angle of the jaw to the middle of the 
clavicle. In its course it crosses the Sterno-mastoid muscle, and runs parallel with 
its posterior border as far as its attachment to the clavicle, where it perforates the 
deep fascia, and terminates in the subclavian vein, on the outer side of, or in front 
of, the Scalenus anticus muscle. In the neck it is separated from the Sterno- 
mastoid by the investing layer of the deep cervical fascia, and is covered by the 
Platysma, the superficial fascia, and the integument. This vein is crossed about 
its middle by the superficialis colli nerve, and throughout the upper half of its 
course is accompanied by the auricularis magnus nerve. The external jugular vein 
varies in size, bearing an inverse proportion to that of the other veins of the neck; 
it is occasionally double. It is provided with two pairs of valves, the lower pair 
being placed at its entrance into the subclavian vein, the upper pair in most cases 
about an inch and a half above the clavicle. The portion of vein between the two 
sets of valves is often dilated, and is termed the sinus. These valves do not prevent 
the regurgitation of the blood or the passage of injection from below upward.1 
Tributaries.-This vein receives the occipital occasionally, the posterior external 
jugular, and, near its termination, the suprascapular and transverse cervical veins. 
It communicates with the anterior jugular, and, in the substance of the parotid, 
receives a large branch of communication from the internal jugular. 
The Posterior External Jugular Vein (v. jugularis posterior) commences in 
the occipital region, and returns the blood from the integument and superficial 
muscles in the upper and back part of the neck, lying between the Splenius and 
Trapezius muscles. It runs down the back part of the neck, and opens into the 
external jugular just below the middle of its course. 
The Anterior Jugular Vein (v. jugularis anterior) commences near the 
hyoid bone from the convergence of the inferior coronary, the submental and the 
mental veins, and communicating branches. It passes down between the median 
line and the anterior border of the Sterno-mastoid, and at the lower part of the 
neck passes beneath that muscle to open into the termination of the external 
jugular or into the subclavian vein (Fig. 465). This vein varies considerably in 
size, bearing almost always an inverse proportion to the external jugular. Most 
frequently there are two anterior jugulars, a right and left, but occasionally only 
one. This vein receives some laryngeal veins, and occasionally a small thyroid 
vein. Just above the sternum the two anterior jugular veins communicate by a 
1 The student may refer to an interesting paper by Dr. Struthers, " On Jugular Venesection in Asphyxia. 
Anatomically and Experimentally Considered, including the Demonstration of Valves in the Veins of the Neck," 
in the Edinburgh Medical Journal for November, 1856.-Ed. of 15th English edition. THE VEINS OE THE NECK 
729 
transverse trunk, which receives tributaries from the inferior thyroid veins. It 
also communicates with the internal jugular. There are no valves in this vein. 
The Internal Jugular Vein (v. jugularis interna') collects the blood from 
the interior of the cranium, from the superficial parts of the face, and from the 
neck. It commences just external to the jugular foramen, at the base of the skull, 
being formed by the coalescence of the lateral and inferior petrosal sinuses (Fig. 
458). At its origin it is somewhat dilated, and this dilatation is called the sinus 
or gulf of the internal jugular vein (bulbus v. jugularis superior). It runs down the 
side of the neck in a vertical direction, lying at first on the outer side of the internal 
carotid artery, and then on the outer side of the common carotid artery, and at 
the root of the neck unites with the subclavian vein to form the innominate vein. 
Just before its termination it is distinctly dilated (bulbus v. jugularis inferior). The 
DORSALIS 
LINGUAE ARTERY- 
LINGUAL VEIN 
VEINS OF 
DORSUM OF- 
TONGUE 
HYPOGLOSSAL NERVE 
Fig. 445.-Veins of the tongue. (Testut, modified from Hirschfeld.) 
internal jugular vein, at its commencement, lies upon the Rectus capitis lateralis, 
and behind the internal carotid artery and the nerves passing through the jugular 
foramen; lower down, the vein and artery lie upon the same plane, the glosso- 
pharyngeal and hypoglossal nerves passing forward between them; the pneumo- 
gastric descends between and behind them in the same sheath, and the spinal 
accessory passes obliquely outward, behind or in front of, the vein. At the root of 
the neck the vein of the right side is placed at a little distance from the artery; on 
the left side it usually lies over the artery at its lower part. The right internal 
jugular vein crosses the first part of the subclavian artery. The internal jugular 
vein is of considerable size, but varies in different individuals, the left one being 
usually the smaller. It is provided with a pair of valves, which are placed at its 
point of termination or from half to three-quarters of an inch above it. 
Tributaries.-This vein receives in its course the facial, lingual, pharyngeal, 
superior, and middle thyroid veins. A branch from the cochlea opens into the 
sinus of the internal jugular vein. A venous plexus from the lateral sinus (plexus 
venosus caroticus internus) surrounds the internal carotid artery in the carotid 
canal and empties into the internal jugular vein. At its point of junction with the 
common facial vein it becomes increased in size. (See Facial Veins, p. 726.) 
The Lingual Veins (vv. linguale) (Fig. 445) commence on the dorsum, sides, and 
under surface of the tongue, and, passing backward, following the course of the 
lingual artery and its branches, terminate in the internal jugular. Sometimes the 
ranine vein, which is a branch of considerable size commencing below the tip of the THE BLOOD-VASCULAR SYSTEM 
730 
tongue, joins the lingual. Generally, however, it passes backward, crosses the 
Hyo-glossus muscle in company with the hypoglossal nerve, and joins the internal 
jugular. The lingual vein receives the sublingual vein and the dorsalis linguae veins. 
The Pharyngeal Veins (vv. pharyngeoe) vary in number. They commence in a 
minute plexus, the pharyngeal plexus (plexus pharyngeus), at the back part and 
sides of the pharynx, and, after receiving meningeal tributaries, the meningeal 
veins (vv. meningea), the Vidian veins (vv. canalis pterygoidei), and the spheno- 
palatine veins, terminate in the internal jugular. They occasionally open into the 
facial, lingual, or superior thyroid vein. 
SUBMENTAL 
LINGUAL 
INFERIOR 
PALATINE 
STERNO-CLEIDO- 
MASTOID MUSCLE 
TEMPORO- 
"MAXILLARY 
SUPERIOR 
THYROID' 
DESCEN DENS 
HYPOGLOSSI. 
NERVE 
COMMON 
CAROTID 
ARTERY 
TRANSVERSE 
CERVICAL 
CEPHALIC 
Fig. 446.-The veins of the neck, viewed from in front. (Spalteholz.) 
SUBCLAVIAN 
The Superior Thyroid Vein (v. thyreoidea superiors') (Fig. 446) commences in the 
substance and on the surface of the thyroid gland by tributaries corresponding 
with the branches of the superior thyroid artery, and terminates in the upper 
part of the internal jugular vein. It receives the superior laryngeal and crico- 
thyroid veins. Some anatomists teach that there are two superior thyroid veins 
on each side, the upper vein being the one just considered, the lower vein being 
the one usually pointed out as the middle thyroid. 
The Middle Thyroid Vein (Fig. 448) collects the blood from the lower part of the 
lateral lobe of the thyroid gland, and, being joined by some veins from the larynx 
and trachea, terminates in the lower part of the internal jugular vein. Often in THE VEINS OF THE NECK 
731 
place of the middle thyroid vein there are two veins, the superior and inferior 
accessory thyroid. These veins pass into the internal jugular. 
Fig. 447.-Diagram showing common arrangement of thyroid veins. (Kocher.) 
SUPERIOR 
THYROID 
ARTERY 
CRICO- 
THYROID 
MUSCLE 
STERNO- 
-THYROID 
MUSCLE 
MIDDLE 
THYROID 
VEIN 
INFERIOR 
THYROID 
VEIN 
INFERIOR 
THYROID 
VEIN 
Fig. 448.-The fascia and middle thyroid veins. The veins here designated the inferior thyroid are called by 
Kocher the thyreoidea ima. (Poirier and Charpy.) 
Veins of the Thyroid Gland1 (Fig. 447).-On the surface of the thyroid glands 
the veins form a plexus between the capsule and the gland. A number of veins 
1 See Kocher's description in Langenbeck's Arch. f. klin. Chir., vol. xxix., and James Berry's description in his 
treatise on Diseases of the Thyroid Gland. THE BLOOD-VASCULAR SYSTEM 
732 
penetrate the capsule and pass into adjacent trunks. The most important veins 
coming from the gland are the superior, middle, and inferior thyroids (or instead 
of the middle thyroid the superior and inferior accessory thyroid) and the 
thyreoidea ima. 
The superior thyroid vein emerges from the summit of the superior horn of the 
gland, runs along by the superior thyroid artery, and terminates in the internal 
jugular vein. A large branch which passes along the inner margin of the upper 
horn and across the upper surface of the isthmus joins the superior thyroid veins 
of each side. The middle thyroid vein when present emerges from the side of the 
gland and empties into the internal jugular. This single vein may be replaced by 
two veins, the superior and inferior accessory thyroid veins. The superior vein 
emerges from the outer surface of the upper horn somewhat below the apex. The 
inferior vein comes from the posterior and inferior portion of the gland. Both 
empty into the internal jugular. The lower surface of the isthmus and the inner 
side of each inferior horn is drained by two veins. Each vein is called the thy- 
reoidea ima (Kocher). The left vein empties into the left innominate vein. The 
right vein empties into either the right or left innominate vein. These veins may 
be very small, may be absent, or may join and form one vein which empties into 
the left innominate. An inferior thyroid is often also present. It comes from the 
outer portion of the inferior horn of the gland and empties into the innominate vein. 
The facial and occipital veins have been described on pages 726 and 727. 
Surgical Anatomy.-The internal jugular vein occasionally requires ligature in cases of septic 
thrombosis of the lateral sinus from suppuration in the middle ear. This is done in order to 
prevent septic emboli being carried into the general circulation. This operation has been 
performed in a number of cases, with satisfactory results. The cases are generally those of 
chronic disease of the middle ear, with discharge of pus which perhaps has existed for many 
years. The patient is seized with acute septic inflammation, spreading to the mastoid cells, 
and, consequent on this, septic thrombosis of the lateral sinus extending to the internal jugular 
vein. Such cases are always extremely grave, for there is danger that a portion of the septic 
clot will be detached and cause septic embolism in the thoracic viscera. If thmmbo-phlebitis 
of the sinus is suspected the mastoid should be opened and cleansed and the sinus should be at 
once exposed and explored. If the sinus is found to be thrombosed the surgeon should at 
once proceed to ligate the internal jugular vein, by an incision along the anterior border of the 
sterno-mastoid, the centre of which is on a level with the greater cornu of the hyoid bone. The 
vein should be ligated in two places and divided between. After the vessel has been secured 
and divided the lateral sinus is to be thoroughly cleared out, and, by removing the ligature from 
the upper end of the divided vein, all septic clots may be removed by syringing from the sinus 
through the vein. If hemorrhage occurs from the distal end of the sinus, it can be arrested by 
careful plugging with antiseptic gauze. 
The thyroid veins are small vessels when the gland is of normal size, but become enormous 
when the gland is much enlarged. 
In the operation of thyroidectomy the veins as well as the arteries are ligated before the gland, 
or rather before one lobe of it is extirpated. 
The Vertebral Vein (v. vertebralis') (Fig. 449) commences by numerous small 
veins from the intraspinal venous plexuses (plexus venosi vertebrates'); these pass 
outward and enter the foramen in the transverse process of the atlas, and descend, 
forming a dense plexus around the vertebral artery in the canal formed by the 
foramina in the transverse processes of the cervical vertebrae.' The vessels of this 
plexus unite at the lower part of the neck into two main trunks, one of which 
emerges from the foramen in the transverse process of the sixth cervical vertebra, 
and the other through that of the seventh. Uniting, these two trunks form a 
single vessel which terminates at the root of the neck in the back part of the 
innominate vein near its origin, its mouth being guarded by a pair of valves. 
On the right side it crosses the first part of the subclavian artery. 
Tributaries.-The vertebral vein receives in its course a vein from the inside 
of the skull through the posterior condyloid foramen. It anastomoses with the THE VEINS OF THE DIPLOE 
733 
occipital vein and receives muscular veins from the muscles in the prevertebral 
region; dorsi-spinal veins, from the back part of the cervical portion of the spine; 
meningo-rachidian veins, from the interior of the spinal canal; the anterior and 
posterior vertebral veins; and close to its termination it is joined by a small vein 
from the first intercostal space which accompanies the superior intercostal artery. 
The Anterior Vertebral or Anterior Deep Cervical Vein commences in a plexus 
around the transverse processes of the upper cervical vertebrae, descends in com- 
pany with the ascending cervical artery between the Scalenus anticus and Rectus 
capitis anticus major muscles, and opens into the vertebral vein just before its 
termination. 
VERTEBRAL- 
POSTERIOR 
EXTERNAL 
JUGULAR 
-VERTEBRAL 
-ASCENDING 
"cervical 
POSTERIOR 
DEEP. 
CERVICAL 
Fig. 449.-The vertebral vein. (Poirier and Charpy.) 
The Posterior Vertebral or Posterior Deep Cervical Vein (v. cervicalis profunda) 
(Fig. 449) accompanies the profunda cervicis artery, lying between the Com- 
plexus and Semispinalis colli. It commences in the suboccipital region by com- 
municating branches from the occipital vein and tributaries from the deep muscles 
at the back of the neck. It receives tributaries from the plexuses around the spinous 
processes of the cervical vertebrae, and terminates in the lower end of the vertebral 
vein. 
The Veins of the Diploe (Vense Diploicae) (Fig. 450). 
The diploe of the cranial bones is channelled in the adult by a number of 
tortuous canals, the diploic canals or canals of Breschet (canales diploid [Brescheti]), 
which are lined by a more or less complete layer of compact tissue. The veins 
they contain are large and capacious, their walls being thin, and formed only of 
endothelium resting upon a layer of elastic tissue, and they present at irregular 
intervals pouch-like dilatations, or culs-de-sac, which serve as reservoirs for the 
blood. These are the veins of the diploe; they can only be displayed by removing 
the outer table of the skull. 
In adult life, as long as the cranial bones are distinct and separable, these 
veins are confined to the particular bones; but in old age, when the sutures are 734 
THE BLOOD-VASCULAR SYSTEM 
united, they communicate with each other and increase in size. These vessels 
communicate, in the interior of the cranium, with the meningeal veins and with 
the sinuses of the dura mater, and on the exterior of the skull with the veins of 
the pericranium. They are divided into the frontal diploic vein (v. diploica fron- 
talis}, which opens into the supraorbital vein by an aperture in the supraorbital 
notch and into the superior longitudinal sinus; the anterior temporal diploic vein 
(y. diploica temporalis anterior}, which is confined chiefly to the frontal bone, 
communicates with the spheno-parietal sinus and, after escaping by an aperture 
in the great wing of the sphenoid, opens into one of the deep temporal veins; the 
posterior temporal, or external parietal diploic vein (y. diploica temporalis posterior}, 
is between the emissarium parietale and the emissarium mastoideum; and the 
occipital diploic vein (y. diploica occipitalis}, the largest of the four, which is 
confined to the occipital bone, and opens into the emissarium occipitale. 
Fig. 450.-Veins of the diploe as displayed by the removal of the outer table of the skull. 
The Emissary Veins are considered on page 743. 
The Meningeal Veins (w. meningea}.-They are numerous in the dura mater, 
are without valves, anastomose freely with each other, do not increase in size as 
they reach the sinus which receives them, and bear no regular relation to the 
meningeal arteries. The middle meningeal artery has two venae comites. The 
other meningeal arteries usually have two apiece, but may have but one. The 
middle meningeal veins (yv. meningece media} accompany the middle meningeal 
artery, are united to the spheno-parietal sinus, pass through the foramen spino- 
sum, and join the pterygoid plexus. The other meningeal veins empty into the 
superior longitudinal sinus and communicate with the plexus of the foramen 
ovale. 
The Cerebral Veins (Vense Cerebri). 
The cerebral veins are remarkable for the absence of valves and for the extreme 
thinness of their coats. The coats are thin because they contain no muscular 
tissue. The cerebral veins may be divided into two sets: the superficial veins, 
which are placed on the surface, and the deep veins, which occupy the interior of 
the organ. The veins of the brain do not accompany associated arteries. THE CEREBBAL VEINS 
735 
The Superficial or Cortical Cerebral Veins (venae cerebri externoe) (Fig. 546) 
ramify upon the surface of the brain, being lodged in the sulci between the con- 
volutions, a few running across the convolutions. They receive branches from the 
substance of the brain and terminate in the sinuses. They are named, from the 
position they occupy, superior, median, and inferior cerebral veins. 
The Superior Cerebral Veins (vv. cerebri superiores), eight to twelve in number 
on each side, return the blood from the convolutions on the superior surface of the 
hemisphere; they pass forward and inward toward the great longitudinal fissure, 
where they receive the median cerebral veins; near their termination they become 
invested with a tubular sheath of the arachnoid membrane, and open into the 
superior longitudinal sinus in the opposite direction to the course of the current of 
the blood. 
The Median Cerebral Veins (v. cerebri mediana) return the blood from the con- 
volutions of the mesial surface of the corresponding hemisphere; they open into 
the superior cerebral veins, or occasionally into the inferior longitudinal sinus. 
The Inferior Cerebral Veins (vv. cerebri injeriores) ramify on the lower part of the 
outer surface and on the under surface of the cerebral hemisphere. Some, collecting 
tributaries from the under surface of the anterior lobes of the brain, terminate in 
the cavernous sinus. One vein of large size, the middle cerebral or superficial 
Sylvian vein (v. cerebri media), commences on the under surface of the temporal 
lobe, and, running along a portion of the fissure of Sylvius, opens into the cav- 
ernous sinus. The great anastomotic vein of Trolard or the superficial communi- 
cating vein establishes a union between the sinuses of the vertex and those of the 
base of the brain. It comes from one of the superior cerebral veins, passes down- 
ward into the fissure of Sylvius, and, by means of the middle cerebral vein, effects a 
communication with the cavernous sinus. The posterior anastomotic vein connects 
the middle cerebral vein with the lateral sinus. Other veins commence on the 
under surface of the base of the brain, and unite to form from three to five veins, 
which open into the superior petrosal and lateral sinuses from before backward. 
The Deep Cerebral, Central, or Ventricular Veins, Veins of Galen (venae 
Galeni, vv. cerebri internee) (Fig. 548), are two in number. Each is formed by 
the union of two veins, the vena corporis striati, and the choroid vein, on either side. 
The deep cerebral veins run backward, parallel with one another, between the 
layers of the velum interpositum, and in the region of the pineal body unite 
to form one vein, the vena magna Galeni (v. cerebri magna), which passes out 
of the brain at the great transverse fissure, between the posterior extremity, or 
splenium, of the corpus callosum and the tubercula quadrigemina, to enter the 
straight sinus. The two deep cerebral veins receive branches from the callosal 
region, from a portion of the occipital lobe, and just before their union each vein 
receives the basilar vein. The vena magna Galeni receives the vermian vein from 
the superficial cerebellar veins. 
The Vena Corporis Striati on each side commences in the groove between the 
corpus striatum and thalamus opticus, receives numerous veins from both of these 
parts, and unites behind the anterior pillar of the fornix with the choroid vein to 
form one of the deep cerebral veins. 
The Choroid Vein (v. choroidea) originates in the extreme end of the middle 
cornu of the lateral ventricle and runs along the whole length of the outer border of 
the choroid plexus, receiving veins from the hippocampus major, the fornix, and 
corpus callosum, and unites, at the anterior extremity of the choroid plexus, with 
the vein of the corpus striatum to form the deep cerebral vein of that side. 
The Basilar Vein (v. basalis) commences at the anterior perforated space at the 
base of the brain by the union of a small anterior cerebral vein, which courses 
backward between the anterior lobes of the cerebrum, with the deep Sylvian vein, 
which descends through the lower part of the Sylvian fissure and receives veins from 736 
THE BLOOD-VASCULAR SYSTEM 
the island of Reil. It passes backward over the crus cerebri, receiving the inferior 
striate vein from the corpus striatum, interpeduncular veins from the interpedun- 
cular space, ventricular veins from the middle cornu of the lateral ventricles, and 
tributaries from the uncinate convolution, and enters the vein of Galen just 
before its junction with the vein of the opposite side. 
The Superficial Cerebellar Veins (Fig. 546) occupy the surface of the cere- 
bellum, and are disposed in two sets, superior and inferior. 
The Superior Superficial Cerebellar Veins (w. cerebelli superiores) pass partly 
forward and inward, across the superior vermiform process, to terminate in lateral 
branches which pass partly to the straight sinus and partly outward to the lateral 
and superior petrosal sinuses. 
The Inferior Superficial Cerebellar Veins (w. cerebelli inferiores), of large size, 
terminate in the lateral, inferior petrosal, and occipital sinuses. 
The Deep Cerebellar Veins bring blood from the interior of the cerebellum 
to the superficial veins. 
Veins of the Pons Varolii.-Veins come from the depth of the pons, the deep 
veins, and empty into a plexus of superficial veins. From this superficial venous 
plexus a superior vein passes to the basilar vein, and an inferior vein either into a 
cerebellar vein or into the superior petrosal sinus. 
Veins of the Medulla Oblongata.-Veins pass from the depth of the medulla and 
end in a plexus on the surface. From this plexus comes an anterior median 
vein, which is a prolongation of a like vein of the spinal cord-a posterior median 
vein corresponding to a like vein of the cord-and small branches which pass 
with the roots of the ninth, tenth, eleventh, and twelfth cranial nerves, and empty 
into the occipital and the inferior petrosal sinuses. 
The perivascular lymph-spaces are especially found in connection with the vessels of the brain. 
These vessels are enclosed in a sheath, which acts as a lymphatic channel, through which the 
lymph is carried to the subarachnoid and subdural spaces, from which it is returned into the 
general circulation. 
The Sinuses of the Dura Mater (Sinus Durae Matris)(Figs.451,452,453,456,457) 
Ophthalmic Veins and Emissary Veins. 
The sinuses of the dura mater are venous channels, analogous to the veins. 
The outer coat of a sinus is formed by the dura mater; the inner coat, by a 
continuation of the lining membrane of the veins. The thick walls of a sinus 
resist intracranial pressure.1 They are divided into two sets: (1) those situated 
at the upper and back part of the skull; (2) those at the base of the skull. The 
former are-the 
Superior Longitudinal Sinus. 
Inferior Longitudinal Sinus. 
Straight Sinus. 
Lateral Sinuses. 
Occipital Sinus. 
The Superior Longitudinal Sinus (sinus sagittal is superior) (Figs. 451,452, 
and 453) occupies the attached margin of the falx cerebri. Commencing at the 
foramen caecum, through which, in the child, it constantly communicates by a 
small branch with the veins of the nasal fossae, it runs from before backward, 
grooving the inner surface of the frontal, the adjacent margins of the two parietal, 
and the superior division of the crucial ridge of the occipital bone, and terminates 
by opening into the torcular Herophili. The sinus is triangular on transverse 
section, is narrow in front, and gradually increases in size as it passes backward. 
On examining its inner surface it presents the internal openings of the superior 
cerebral veins, which run, for the most part, from behind forward, and open 
1 A. W. Hughes. THE SINUSES OF THE DURA MATER 
737 
chiefly at the back part of the sinus, their orifices being concealed by fibrous 
folds; numerous fibrous bands, chordae Willisii (Fig. 453), are also seen extend- 
ing transversely across the inferior angle of the sinus; and some small, white, 
projecting bodies, the glandulae Pacchioni (granidationes arachnoidales). This 
sinus communicates by numerous small apertures with spaces in the dura 
mater known as lacunae laterales or parasinoidal spaces (Fig. 453). The 
SUPERIOR 
LONGITUDINAL 
SINUS 
STRAIGHT 
SINUS 
LATERAL 
SINUS 
Fig. 451.-Coronal section of the skull to show the situations and shapes of the chief sinuses. 
(Poirier and Charpy.) 
Pacchionian bodies project into these spaces. This sinus receives the superior 
cerebral veins, numerous veins from the diploe and dura mater, the outlets of the 
parasinoidal spaces, and, at the posterior extremity of the sagittal suture, veins 
from the pericranium, which pass through the parietal foramina. In children a 
twig from the longitudinal sinus passes through the foramen caecum and into 
the nose. 
Foramen cxcurn. 
Torcular herophili 
Fig. 452.-Vertical section of the skull, showing the sinuses of the dura mater. 
The Torcular Herophili or the confluence of the sinuses (Figs. 452 and 456) is the 
dilated extremity of the superior longitudinal sinus. It is of irregular form, and 738 
THE BLOOD-VASCULAR SYSTEM 
is lodged on one side (generally the right) of the internal occipital protuberance. 
From it the lateral sinus of the side to which it is deflected is derived. It receives 
also the blood from the occipital sinus. 
The Inferior Longitudinal Sinus (sinus sagittalis inferior) (Fig. 452), more 
correctly described as the inferior longitudinal vein, is contained in the posterior 
part of the free margin of the falx cerebri. It is of a cylindrical form, increases 
in size as it passes backward, and terminates in the straight sinus. It receives 
several veins from the falx cerebri, and occasionally a few from the mesial surface 
of the hemispheres. 
The Straight Sinus (sinus rectus') (Figs. 451 and 452) is situated at the line of 
junction of the falx cerebri with the tentorium. It is triangular in form, increases 
in size as it proceeds backward, and runs obliquely downward and backward from 
MENINGEAL 
VEIN 
SUPERIOR 
- LONGITUDINAL 
SINUS 
PARASI- 
NOIDAL 
SINUS 
PARASINOIDAL 
SINUS 
Fig. 453. --Superior longitudinal sinus seen from above after removal of the skull-cap. The chordae Willisii 
are clearly visible. The para-sinoidal sinuses are also well shown. Probes passing from the latter to the 
longitudinal sinus show that they communicate. (Poirier and Charpy.) 
the termination of the inferior longitudinal sinus to the lateral sinus of the oppo- 
site side to that into which the superior longitudinal sinus is prolonged. It com- 
municates by a cross-branch with the torcular Herophili. Besides the inferior 
longitudinal sinus, it receives the vena magna Galeni and the superior cerebellar 
veins. A few transverse bands cross its interior. This sinus is usually considered 
to be formed by the union of the great vein of Galen and the inferior longitudinal 
sinus. 
The Lateral Sinus (sinus transversus) (Figs. 451, 452, 456, and 457) is of 
large size. There are two lateral sinuses situated in the attached margin of 
the tentorium cerebelli throughout most of its extent. They commence at THE SINUSES OF THE DURA MATER 
739 
the internal occipital protuberance, one, generally the right, being the direct 
continuation of the superior longitudinal sinus, the other of the straight sinus. 
Each passes outward and forward, describing a slight curve with its convexity 
upward, to the base of the petrous portion of the temporal bone, then, leaving 
the tentorium, curves downward and inward to reach the jugular foramen, 
where it terminates in the internal jugular vein. It rests, in its course, upon 
the inner surface of the occipital, the posterior inferior angle of the parietal, 
and the mastoid portion of the temporal bone, and on the occipital again, at 
the jugular process, just before its termination. The portion of the sinus rest- 
ing on the mastoid process of the temporal and the jugular process of the 
occipital bone is not covered by the tentorium and is often called the sigmoid 
sinus because of its shape, which resembles the letter S. These sinuses are fre- 
quently of unequal size, that formed by the superior longitudinal sinus being 
the larger, and they increase in size as they proceed from behind forward. The 
horizontal portion is of a triangular form, the curved portion semicylindrical. 
Their inner surface is smooth, and not crossed by the fibrous bands found in the 
other sinuses. The lateral sinuses receive the blood from the superior petrosal 
sinuses at the base of the petrous portion of the temporal bone, and they unite 
with the inferior petrosal sinus, just external to the jugular foramen, to form the 
internal jugular vein (Fig. 457). They communicate with the veins of the 
pericranium by means of the mastoid and posterior condyloid veins, and they 
receive some of the inferior cerebral and inferior cerebellar veins, some veins 
from the diploe, and often veins from the internal ear {w. auditivoe internee), 
which come out of the internal auditory meatus. The petro-squamous sinus, when 
present, runs backward along the junction of the petrous and squamous portions 
of the temporal bone, and opens into the lateral sinus. 
Surgical Anatomy.-The lateral sinus may, as a result of middle-ear disease, be attacked by 
suppurative inflammation, which leads to blocking {septic thrombo-phlebitis). In such a case 
the surgeon will be obliged fo open the sinus to remove infected clot and tie the internal jugular 
vein to intercept thrombi. The lines overlying the sinus is as follows: Draw a line horizontally 
outward from the occipital protuberance to a point one inch posterior to a vertical line drawn 
through the external auditory meatus and from this point drop a second line to the mastoid 
process. 
The Occipital Sinus {sinus occipitalis) (Fig. 452) is the smallest of the cranial 
sinuses. There is often but a single occipital sinus, but occasionally there are 
two. It is situated in the attached margin of the falx cerebelli. It commences 
by several small veins around the margin of the foramen magnum, one of which 
joins the termination of the lateral sinus; it communicates with the posterior 
spinal veins and terminates in the torcular Herophili. 
The sinuses at the base of the skull are-the 
Cavernous Sinuses. 
Spheno-parietal Sinuses. 
Circular Sinus. 
Superior Petrosal Sinuses 
Inferior Petrosal Sinuses. 
Transverse Sinus. 
The Cavernous Sinus {sinus cavernosus) (Figs. 456 and 457) is named from 
presenting a reticulated structure, due to being traversed by numerous interlacing 
filaments (Fig. 454). There are two cavernous sinuses, of irregular form, larger 
behind than in front, and placed one on each side of the sella turcica, extending 
from the sphenoidal fissure to the apex of the petrous portion of the temporal bone. 
Each receives anteriorly the ophthalmic vein through the sphenoidal fissure, and 
opens behind into the petrosal sinuses. On the inner wall of each sinus is found 
the internal carotid artery, accompanied by filaments of the carotid plexus and 
by the sixth nerve; and on its outer wall, the third, fourth, and ophthalmic division 740 
THE BLOOD-VASCULAR SYSTEM 
of the fifth nerve (Fig. 454). These parts are separated from the blood flowing 
along the sinus by the lining membrane, which is continuous with the inner coat 
of the veins. The cavernous sinuses receive some of the cerebral veins, and also 
the spheno-parietal sinuses. They communicate with the lateral sinuses by 
means of the superior and inferior petrosal sinuses, and with the facial veins 
through the ophthalmic veins. They also communicate with each other by means 
of the circular sinus. 
CAVERNOUS 
SINUS 
.TH IR D 
NERVE 
TRANSVERSE 
SINUS 
I NT. 
CAR. 
ART. 
-FOURTH 
NERVE 
SIXTH 
'NERVE 
OPHTHALMIC 
DIVISION OF 
FIFTH NERVE 
SUPERIOR MAXIL- 
LARY DIVISION 
OF FIFTH NERVE 
Fig. 454.-Frontal section through the right cavernous sinus. (Spalteholz.) 
Surgical Anatomy.-An arterio-venous communication may be established between the 
cavernous sinus and the carotid artery, as it lies in it, giving rise to a pulsating tumor in the 
orbit. Such a communication may be the result of injury, such as a bullet wound, a stab, or 
a blow or fall sufficiently severe to cause a fracture of the base of the skull in this situation, 
or it may occur from the rupture of an aneurism or a diseased condition of the internal 
carotid artery. The disease begins with sudden noise and pain in the head, followed by 
exophthalmos, swelling and congestion of the lids and conjunctivse. A pulsating tumor 
develops at the margin of the orbit, with thrill and the characteristic bruit; accompanying 
these symptoms there may be impairment of sight, paralysis of the iris and orbital muscles, 
and pain of varying intensity. In some cases the opposite orbit becomes affected by the passage 
of the arterial blood into the opposite sinus by means of the circular sinus. Or the arterial 
blood may find its way through the emissary veins into the pterygoid plexus, and thence into the 
veins of the face. Pulsating tumors of the orbit may also be due to traumatic aneurism of 
one of the orbital arteries, and symptoms resembling those of pulsating tumor may be produced 
by pressure on the ophthalmic vein, as it enters the sinus, by an aneurism of the internal 
carotid artery. 
The Spheno-parietal Sinus or Sinus Alae Parvae {sinus sphenoparietalis).- 
Each of these sinuses is lodged in the dura mater on the under surface of the 
lesser wing of the sphenoid bone. It takes origin from one of the middle menin- 
geal veins, usually receives blood from the diploe of the skull, passes inward, and 
ends in the anterior part of the cavernous sinus. 
The Ophthalmic Veins are two in number, superior and inferior. 
The superior ophthalmic vein {v. ophthalmica superior) (Fig. 455) begins as the 
naso-frontal vein (v. nasofrontalis), at the inner angle of the orbit, which communi- 
cates with the angular vein. It joins the angular vein with the cavernous sinus; 
it pursues the same course as the ophthalmic artery, and receives tributaries corre- 
sponding to the branches derived from that vessel. Forming a short single trunk, 
it passes through the inner extremity of the sphenoidal fissure, and terminates in 
the cavernous sinus. It anastomoses with the inferior ophthalmic vein and receives 
lachrymal, anterior, and posterior ethmoidal and muscular branches, and veins 
of the eyelids and of the bulbus oculi. THE SINUSES OF THE DITA MATER 
741 
The inferior ophthalmic vein (y. ophthalmica inferior) (Fig. 455) arises in the veins 
of the eyelids and lachrymal sac, receives the veins from the floor of the orbit, and 
SUPERIOR 
OPHTHALMIC 
CAVERNOUS 
SINUS 
INFERIOR 
OPHTHALMIC 
Fig. 455 -Veins of the orbit. (Poirier and Charpy.) 
from the portion of the nasal fossa supplied by the anterior and posterior ethmoidal 
arteries. It either passes out of the orbit through the spheno-maxillary fissure to 
join the pterygoid plexus of veins, or else, passing backward through the sphenoidal 
Opening of mastoid 
vein. 
Fig. 456.-The sinuses at the base of the skull. 
Torcular Herophili. 
fissure, it enters the cavernous sinus, either by a separate opening, or, more fre- 
quently, in common with the superior ophthalmic vein. It receives muscular 742 
THE BLOOD-VASCULAR SYSTEM 
branches and veins of the bulbus oculi, and anastomoses with the superior 
ophthalmic vein. 
The Circular Sinus (sinus circularise (Figs. 454 and 456) is formed by two 
transverse vessels, the anterior and posterior intercavernous sinuses (sinus inter- 
cavernous anterior and sinus intercavernous posterior), which connect together the 
two cavernous sinuses; the one passing in front and the other behind the pituitary 
body, and thus forming with the cavernous sinuses a venous circle around that 
body. The anterior one is usually the larger of the two, and one or other is occa- 
sionally found to be absent. 
Falx cerebri 
■Optic nerve 
■lot. carotid artery 
■Motor oculi nerve 
■Dorsum sellte 
Inferior 
petrosal sinus 
9th, 10th, and 11th 
cranial nerves 
Lateral sinus 
The Superior Petrosal Sinus {sinus petrosus superior) (Figs. 452 and 456) 
is situated along the superior border of the petrous portion of the temporal 
bone, in the front part of the attached margin of the tentorium. It is small 
and narrow, and connects together the cavernous and lateral sinuses at each side. 
It receives some cerebellar and inferior cerebral veins, and usually veins from the 
tympanic cavity {vv. auditivce internee). 
The Inferior Petrosal Sinus {sinus petrosus inferior) (Figs. 452 and 456) is 
situated in the groove formed by the junction of the posterior border of the 
petrous portion of the temporal with the basilar process of the occipital bone. 
It commences in front at the termination of the cavernous sinus, and behind joins 
the lateral sinus after it has passed through the jugular foramen; the junction of 
these two sinuses forming the commencement of the internal jugular vein. The 
inferior petrosal sinus receives a vein from the internal ear and also veins from 
the medulla, pons, and under surface of the cerebellum. 
The junction of the two sinuses takes place at the lower border of, or just 
external to, the jugular foramen. The exact relation of the parts to one another 
Fig. 457.-Relation of nerves to sinuses in jugular foramen. (Henle.) THE SINUSES OF THE DURA MATER 
743 
in the foramen is as follows: The inferior petrosal sinus is in front, with the 
meningeal branch of the ascending pharyngeal artery, and is directed obliquely 
downward and backward; the lateral sinus is situated at the back part of the 
foramen with a meningeal branch of the occipital artery, and between the two are 
the glosso-pharyngeal, pneumogastric, and spinal accessory nerves (Fig. 457). 
These three sets of structures are divided from each other by two processes of 
fibrous tissue. The junction of the sinuses takes place superficial to the nerves, 
so that these latter lie a little internal to the venous channels in the foramen (see 
Fig. 457). These sinuses are semicylindrical in form. 
The Transverse or Basilar Sinus (plexus basilar is) (Figs. 456 and 457) con- 
sists of several interlacing veins between the layers of the dura mater over the 
basilar process of the occipital bone, which serve to connect the two inferior 
petrosal sinuses. With them the anterior spinal veins communicate. 
Emissary Veins (emissaria).-The emissary veins are vessels which pass 
through apertures in the cranial wall and establish communications between the 
sinuses inside the skull and the diploic veins in the diploe, and the veins external 
to the skull. Some of these are always present, others only occasionally so. 
They vary much in size in different individuals. The principal emissary veins 
are the following: 1. A vein, almost always present, which passes through the 
mastoid foramen (emissarium viastoideum) and connects the lateral sinus with 
the posterior auricular or with an occipital vein. 2. A constant vein which 
passes through the parietal foramen (emissarium parietale) and connects the 
superior longitudinal sinus with the veins of the scalp. 3. A plexus of minute veins 
which pass through the anterior condyloid foramen (emissarium condyloideum) 
and connect the occipital sinus with the vertebral vein and deep veins of the neck. 
4. An inconstant vein which passes through the posterior condyloid foramen and 
connects the lateral sinus with the deep veins of the neck. 5. One or two veins 
of considerable size which pass through the foramen ovale and connect the cav- 
ernous sinus with the pterygoid and pharyngeal plexuses. 6. Two or three small 
veins which pass through the foramen lacerum medium and connect the cavernous 
sinus with the pterygoid and pharyngeal plexuses. 7. There is sometimes a small 
vein connecting the same parts and passing through the inconstant foramen of 
Vesalius at the root of the pterygoid process of the sphenoid bone. 8. A plexus of 
veins passing through the carotid canal and connecting the cavernous sinus with 
the internal jugular vein. 9. A small vein (emissarium occipitale) usually con- 
nects the occipital vein with tlie lateral sinus or the torcular Herophili and the 
occipital diploic vein. 
Surgical Anatomy.-These emissary veins are of great importance in surgery. In addition 
to them there are, however, other communications between the intra- and extra-cranial circula- 
tion, as, for instance, the communication of the angular and supra-orbital veins with the ophthal- 
mic vein at the inner angle of the orbit, and the communication of the veins of the scalp with 
the diploic veins. Through these communications inflammatory processes commencing on the 
outside of the skull may travel inward, leading to osteo-phlebitis of the diploe and inflammation 
of the membranes of the brain. To this in former days was to be attributed one of the principal 
dangers of scalp wounds and other injuries of the scalp. 
By means of these emissary veins blood may be abstracted almost directly from the intra- 
cranial circulation. For instance, leeches applied behind the ear abstract blood almost directly 
from the lateral sinus by means of the vein passing through the mastoid foramen. Again, 
epistaxis in children will frequently relieve severe headache, the blood which flows from the nose 
being derived from the longitudinal sinus by means of the vein which passes through the foramen 
caecum, which is another communication between the intracranial and extracranial circulation 
constantly found in children. 744 
THE BLOOD-VASCULAR SYSTEM 
VEINS OF THE UPPER EXTREMITY AND THORAX 
The veins of the Upper Extremity are divided into two sets, superficial and 
deep. 
The Superficial Veins are placed immediately beneath the integument between 
the layers of superficial fascia. 
POSTERIOR 
ULNAR- 
.SUPERFICIAL 
RADIAL 
DORSAL 
"VENOUS ARCH 
DORSAL 
INTEROSSEOUS 
.VENOUS 
'arch 
Fig. 458.-The veins on the dorsum of the hand. (Bourgery.) 
The Deep Veins accompany the arteries, and constitute the vente comites of 
those vessels. 
Both sets of vessels are provided with valves, which are more numerous in the 
deep than in the superficial veins. THE SUPERFICIAL VEINS OF THE UPPER EXTREMITY 
745 
The Superficial Veins of the Upper Extremity (Fig. 459). 
The superficial veins of the upper extremity are-the 
Superficial Veins of the Hand. 
Anterior Ulnar. 
Posterior Ulnar. 
Common Ulnar. 
Radial. 
Median. 
Median Cephalic. 
Median Basilic. 
Basilic. 
Cephalic. 
The Superficial Veins of the Hand and Fingers (Figs. 458 and 459) are 
principally situated on the dorsal surface. These dorsal veins begin in each finger 
as a venous plexus, in which are distinct veins running in a longitudinal direction, 
and called dorsal digital veins (yv. digitales dorsales proprice). The dorsal digital 
veins terminate over the first phalanges, in the venous arches of the fingers (arcus 
venosi digitales). From these arches take origin the four dorsal interosseous or 
the interdigital veins (vv. metacarpeoe dorsales). These veins form the dorsal venous 
plexus of the hand (rete venosum dor sale manus). This plexus lies in a line with the 
lower ends of the shafts of the metacarpal bones. It receives the - dorsal inter- 
osseous veins, the radial digital vein of the index finger, and numerous superficial 
veins from the back of the hand. It gives origin to the superficial radial vein and 
the posterior ulnar vein. The superficial veins of the palmar surface are of less 
diameter than the dorsal veins. They arise from each of the phalanges by a 
plexus (vv. digitales volares propriai). Vessels at the edges of the fingers take most 
of the blood to the dorsal veins. There are also veins in the finger webs (vv. inter- 
capitulares), which take blood from the palm to the dorsum. A superficial plexus, 
the palmar plexus, lies upon the palmar fascia, the fascia of the thenar eminence, 
and the fascia of the hypothenar eminence. 
The Anterior Ulnar Vein (v. ulnaris anterior) (Fig. 459) commences on the 
anterior surface of the ulnar side of the hand and wrist, and ascends along the 
anterior surface of the ulnar side of the forearm to the bend of the elbow, where 
it joins with the posterior ulnar vein to form the common ulnar. Occasionally it 
opens separately into the median basilic vein. It communicates with branches 
of the median vein in front and with the posterior ulnar behind. 
The Posterior or Dorsal Ulnar Vein (v. ulnaris posterior) (Fig. 458) commences 
on the posterior surface of the ulnar side of the wrist. It runs on the posterior 
surface of the ulnar side of the forearm, and just below the elbow unites with 
the anterior ulnar vein to form the common ulnar, or else joins the median 
basilic and helps to form the basilic. It communicates with the deep veins 
of the palm by a branch which emerges from beneath the Abductor minimi digiti 
muscle. 
The Common Ulnar Vein (v. ulnaris communis) (Fig. 459) is a short trunk 
which is not constant. When it exists it is formed by the junction of the two 
preceding veins, and, passing upward and outward, joins the median basilic to 
form the basilic vein. When it does not exist the anterior and posterior ulnar 
veins open separately into the median basilic vein. 
The Radial Vein (v. radialis) (Figs. 459 and 460) commences upon the dorsal 
surface of the wrist, communicating with the deep veins of the palm by a branch 
which passes through the first interosseous space. The radial vein soon forms a 
large vessel, which ascends along the radial side of the forearm and receives 
numerous veins from both its surfaces. At the bend of the elbow it unites with 
the median cephalic to form the cephalic vein. Spalteholz considers the ulnar 
vein as a portion of the basilic and the radial vein a portion of the cephalic. 
The Median Vein (v. mediana cubiti) (Fig. 459) ascends on the front of the 
forearm, and communicates with the anterior ulnar and radial veins. At the bend 746 
THE BLOOD-VASCULAR SYSTEM 
of the elbow it receives a branch of 
communication from the deep veins, 
the deep median vein, and divides into 
two branches, the median cephalic and 
median basilic, which diverge from each 
other as they ascend. 
The Median Cephalic (u mediana 
cephalica) (Fig. 459), usually the smaller 
of the two, passes outward in the groove 
between the Supinator longus and Bi- 
ceps muscles, and joins with the radial 
to form the cephalic vein. The branches 
of the external cutaneous nerve pass 
beneath this vessel. 
The Median Basilic Vein (v. mediana 
basilica) (Fig. 459) passes obliquely in- 
ward, in the groove between the Biceps 
and Pronator radii teres muscles, and 
joins the common ulnar to form the 
basilic. This vein passes in front of 
the brachial artery, from which it is 
separated by a fibrous expansion, the 
bicipital fascia, which is given ofi' from 
the tendon of the Biceps to the fascia 
covering the Flexor muscles of the fore- 
arm. Filaments of the internal cuta- 
neous nerve pass in front as well as 
behind this vessel.1 
Internal 
cutaneous 
nerve. 
Median cephalic. 
External 
cutaneous nerve 
Median 
basilic. 
'Common 
ulnar. 
Venesection is usually performed at the 
bend of the elbow, and as a matter of practice 
the largest vein in this situation is commonly 
selected. This is usually the median basilic, 
and there are anatomical advantages and dis- 
advantages in selecting this vein. The advan- 
tages are, that in addition to its being the 
largest, and therefore yielding a greater supply 
of blood, it is the least movable and can be 
easily steadied on the bicipital fascia on which 
it rests. The disadvantages are, that it is in 
close relationship with the brachial artery, 
separated only by the bicipital fascia; and 
formerly, when venesection was frequently 
practised, arterio-venous aneurism was no 
uncommon result of this practice. Another 
disadvantage is. that the median basilic is 
crossed by some of the branches of the internal 
cutaneous nerve, and these may be divided 
in the operation, giving rise to "traumatic 
neuralgia of extreme intensity" (Tillaux). 
The Basilic Vein (v. basilica} (Figs. 
460 and 462) is of considerable size and 
is formed by the coalescence of the 
common ulnar vein with the median 
Fig. 459.-The superficial veins of the flexor aspect 
of the upper extremity. 
1 Cruveilhier says: "Numerous varieties are observed in the disposition of the veins of the elbow; some- 
times the common median vein is wanting; but in those cases its two branches are furnished by the radial vein, 
and the cephalic is almost always in a rudimentary condition. In other cases only two veins are found at the 
bend of the elbow, the radial and ulnar, which are continuous, without any demarcation, with the cephalic and 
basilic."-Ed. of 15th English edition. THE DEEP VEINS OE THE UPPER EXTREMITY 
747 
basilic. It passes upward along the inner side of the Biceps muscle and pierces 
the deep fascia a little below the middle of the arm. The opening in the fascia 
is known as the semilunar hiatus (hiatus semilunaris). The vein ascends in the 
course of the brachial artery to the lower border of the tendons of the Latissimus 
dorsi and Teres major muscles, and is continued onward as the axillary vein. 
The Cephalic Vein (y. cephalica) (Fig. 459) is formed by the union of the 
median cephalic and the radial veins. It courses along the outer border of the 
Biceps muscle, lying in the same groove with the upper external cutaneous branch 
of the musculo-spiral nerve, to the upper third of the arm; it then passes in the 
interval between the Pectoralis major and Deltoid muscles, lying in the same 
groove with the descending or humeral branch of the acromial-thoracic artery. 
It pierces the costo-coracoid membrane, and, crossing the axillary artery, ter- 
minates in-the axillary vein just below the clavicle. This vein is occasionally 
connected with the external jugular or subclavian by a branch which passes 
from it upward in front of the clavicle. 
The Deep Veins of the Upper Extremity (Fig. 460). 
The deep veins of the upper extremity follow the course of the arteries, forming 
their venae comites or companion veins. Usually there is one vein lying on each 
side of the corresponding artery, and they are connected at intervals by short 
transverse branches. 
There are two digital veins accompanying each artery along the sides of the 
fingers: these, uniting at their base, pass along the interosseous spaces in the 
palm, and terminate in the two venae comites which accompany the superficial 
palmar arch. Branches from these vessels on the radial side of the hand accom- 
pany the superficialis volte, and on the ulnar side terminate in the deep ulnar 
veins (Fig. 460). The deep ulnar veins, as they pass in front of the wrist, com- 
municate with the interosseous and superficial veins, and at the elbow unite with 
the deep radial veins to form the vena? comites of the brachial artery. The venae 
comites of the brachial communicate by numerous transverse branches, which 
cross over or under the artery. 
The Interosseous Veins (Fig. 460) accompany the anterior and posterior 
interosseous arteries. The anterior interosseous veins commence in front of the 
wrist, where they communicate with the deep radial and ulnar veins; at the upper 
part of the forearm they receive the posterior interosseous veins, and terminate in 
the venae comites of the ulnar artery. 
The Deep Palmar Veins accompany the deep palmar arch, being formed by 
tributaries which accompany the ramifications of that vessel. At the wrist they 
receive a dorsal and a palmar tributary from the thumb. The deep palmar veins 
communicate with the deep ulnar veins at the inner side of the hand, and on the 
outer side terminate in the deep radial veins (Fig. 460), which are the venae 
comites of the radial artery. Accompanying the radial artery the deep radial 
veins terminate in the venae comites of the brachial artery. 
The Brachial Veins (vv. brachiales) (Fig. 460) are placed one on each side of 
the brachial artery, receiving tributaries corresponding with the branches given off 
from that vessel; at the lower margin of the Subscapularis muscle they join the 
axillary vein. 
These deep veins have numerous anastomoses, not only with each other, but 
also with the superficial veins. One of the brachial veins empties into the 
axillary, the other, usually the smaller, generally unites with the basilic. 
The Axillary Vein (v. axillaris) (Fig. 461) is of large size, and may be regarded 
as the continuation upward of the basilic vein, or as formed by the fusion of a 
brachial vein with the basilic vein. If the first view is accepted a brachial vein 
is described as one of the tributaries of the axillary vein. The axillary vein com- THE BLOOD VASCULAR SYSTEM 
748 
mences at the lower border of the tendons of the Teres major and Latissimus dorsi 
muscles, increases in size as it ascends, by receiving tributaries corresponding with 
the branches of the axillary artery, and terminates immediately beneath the clavicle 
at the outer border of the first rib, where it becomes the subclavian vein. This 
vessel is covered in front by the Pectoral muscles and costocoracoid membrane, 
and lies on the thoracic side of the axillary artery, which it partially overlaps. It 
receives the brachial veins, the venae comites of the axillary artery except the cir- 
cumflex veins; and near its termination the cephalic vein. This vein is provided 
with a pair of valves opposite the lower border of the Subscapularis muscle; valves 
are also found at the termination of the cephalic and subscapular veins. The 
circumflex veins end in the subscapular or one of the brachial veins. 
The Long Thoracic Branch (y. thoracalis lateralis) (Fig. 462) receives the thoracico- 
epigastric vein (y. thoracoepigastrica), which comes all the way from the superficial 
epigastric or from the femoral vein. 
The Costo-axillary Veins (yv. costoaxillares) (Fig. 462) come from the first six 
intercostal spaces and bring blood from the intercostal veins to the axillary. 
VENXE COMITES 
OF BRACHIAL 
ARTERY 
ANASTOMOSIS 
OF RADIAL 
AND ULNAR 
INTEROSSEOUS 
veins" 
RADIAL DEEP 
VEINS 
ULNAR DEEP 
VEINS 
Fig. 460.-The deep veins of the upper extremity. (Bourgery.) 
Surgical Anatomy.-There are several points of surgical interest in connection with the 
axillary vein. Being more superficial, larger, and slightly overlapping the axillary artery, it is 
more liable to be wounded in the operation of extirpation of the axillary glands, especially as 
these glands, when diseased, are apt to become adherent to the vessel. When wounded there 
is always danger of air being drawn into its interior, and death resulting. This is due not only 
to the fact that it is near the thorax, and therefore liable to be influenced by the respiratory 
movements, but also because it is adherent by its anterior surface to the costo-coracoid membrane, 
and therefore if wounded is likely to remain patulous and favor the chance of air being sucked 
in. This adhesion of the vein to the fascia prevents its collapsing, and therefore favors the 
furious bleeding which takes place in these cases. THE DEEP VEINS OF THE UPPER EXTREMITY 
749 
To avoid wounding the axillary vein in the extirpation of glands from the axilla no undue 
force should be used in isolating the glands. If the vein is found to be so embedded in the 
malignant deposit that the latter cannot be removed without taking away a part of the vein, 
this must be done, the vessel having been first ligated above and below. 
AXILLARY 
ARTERY 
MUSCULO- 
CUTANEUS NERVE 
MEDIAN NERVE 
ANTERIOR 
CIRCUMFLEX 
COSTO-AXI LLAR Y 
SUBSCAPULAR 
Fig. 461.-The veins of the right axilla, viewed from in front. (Spalteholz.) 
LONG THORACIC 
COSTO-AXILLARY 
The Subclavian Vein (v. subclavia) (Figs. 421 and 446), the continuation of the 
axillary, extends from the outer border of the first rib to the inner end of the clavicle, 
where it unites with the internal jugular to form the innominate vein. It is in 
relation, in front, with the clavicle and Subclavius muscle; behind and above, with 
the subclavian artery, from which it 
is separated internally by the Scal- 
enus anticus muscle and phrenic 
nerve. Below, it rests in a depres- 
sion on the first rib and upon the 
pleura. Above, it is covered by the 
cervical fascia and integument. 
An expansion of the aponeurosis 
of the Subclavius muscle lies upon 
the vein (Fig. 462). 
The subclavian vein occasionally 
rises in the neck to a level with the 
third part of the subclavian artery, and in two instances has been seen passing 
with this vessel behind the Scalenus anticus. This vessel is usually provided 
with valves about an inch from its termination in the innominate, just external 
to the entrance of the external jugular vein. 
Tributaries.-It receives the external and anterior jugular veins and a small 
branch from the cephalic, outside the Scalenus, and on the inner side of that 
muscle the internal jugular vein. At the angle of junction with the internal 
PECTORALIS 
MAJOR 
MUSCLE 
SUBCLAVIUS 
MUSCLE 
Fig. 462.-The aponeurotic expansion of the Subclavius 
muscle over the subclavian vein. (Poirier and Charpy.) THE BLOOD-VASCULAR SYSTEM 
750 
jugular the left subclavian vein receives the thoracic duct (Fig. 463), while the 
right subclavian vein receives the right lymphatic duct. 
The Innominate or Brachio-cephalic Veins (yv. anonyma?) (Fig. 464) are 
two large trunks, placed one on each side of the root of the neck, and formed by 
the union of the internal jugular and subclavian veins of the corresponding side. 
The Right Innominate Vein (y. anonyma dextro) is a short vessel, an inch 
in length, which commences at the inner end of the clavicle, and, passing almost 
vertically downward, joins with the left innominate vein just below the cartilage 
of the first rib, close to the right border of the sternum, to form the superior vena 
cava. It lies superficial and external to the innominate artery; on its right side 
is the phrenic nerve, and the pleura is here interposed between it and the apex of 
the lung. This vein, at the angle of junction of the internal jugular with the sub- 
clavian, receives the right vertebral vein, and, lower down, the right internal 
mammary, right inferior thyroid, and sometimes the right thyroidea ima and the 
right superior intercostal veins. 
The Left Innominate Vein (y. anonyma sinistra), about two and a half 
inches in length, and larger than the right, passes from left to right across the 
upper and front part of the chest, at the same time inclining downward, and unites 
LONGUS COLLI MUSCLE 
COMMON CAROTID 
"ARTERY 
LEFT PNEUMOGASTRIC 
NERVE 
VERTEBRAL ARTERY 
-VERTEBRAL VEIN 
-THORACIC DUCT 
INTERNAL JUGULAR 
VEIN 
EXTERNAL JUGULAR 
VEIN 
ANTERIOR JUGULAR 
VEIN 
SUBCLAVIAN 
VEIN 
Fig. 463.-The bend of the thoracic duct at its termination in the subclavian vein. (Poirier and Charpy.) 
with the right innominate vein to form the superior vena cava. It is in relation, 
in jront, with the first piece of the sternum, from which it is separated by the 
Sterno-hyoid and Sterno-thyroid muscles, the thymus gland or its remains, and some 
loose areolar tissue. Behind, it lies across the roots of the three large arteries 
arising from the arch of the aorta. This vessel is joined by the left vertebral, 
left internal mammary, left inferior thyroid, left thyroidea ima, and the left 
superior intercostal veins, and occasionally some thymic and pericardiac veins, 
and the right thyroidea ima. There are no valves in the innominate veins. 
Peculiarities.-Sometimes the innominate veins open separately into the right auricle; in such 
cases the right vein takes the ordinary course of the superior vena cava; but the left vein-the left 
superior vena cava, as it is termed-after communicating by a small branch with the right one, 
passes in front of the root of the left lung, and, turning to the back of the heart, receives the 
cardiac veins, and terminates in the back of the right auricle. This occasional condition in the 
adult is due to the persistence of the early foetal condition, and is the normal state of things in 
birds and some mammalia. 
The Internal Mammary Vein (v. mammaria interna) corresponds to the internal 
mammary artery, follows the course of that vessel, and receives branches corre- 
sponding with those derived from it. There are two internal mammary veins in the 
region of the Triangularis sterni muscle, but above this point the vein is single. The 
double vein is formed by the union of the venae comites of the superior epigastric THE DEEP VEINS OF THE UPPER EXTREMITY 
751 
artery (vv. epigastrica; superiores} and the venae comites of the musculo-phrenic 
artery (vv. musculophrenicce}. It receives the twelve anterior intercostal veins from 
the upper six intercostal spaces of the corresponding side-six anterior perforating 
veins (rami perferantes}- 
veins from the surface of the 
sternum (rami sternales} - 
muscular veins, and vessels 
from the mediastinum and 
pleura. The two veins of 
each side unite into a single 
trunk, at the upper margin 
of the triangularis sterni 
muscle, which terminates in 
the innominate vein. 
The Vertebral Vein (see 
p. 732). 
The Inferior Thyroid Veins 
(vv. thyreoidea; injeriores} 
(Fig. 464), two, frequently 
three or four, in number, 
arise in the venous plexus 
on the thyroid body (plexus 
thyreoideus impar}, commu- 
nicating with the middle 
and superior thyroid veins. 
(See Kocher's views, pages 
731 and 732.) Kocher states 
that two thyroidea ima veins 
are present, and that inferior 
thyroid veins may also be 
present. The veins from the 
lower portion of the gland 
form a plexus in front of the 
trachea, behind the Sterno- 
thyroid muscles. From this 
plexus a left vein descends 
and joins the left innomi- 
nate trunk, and a right vein 
passes obliquely downward 
and outward across the in- 
nominate artery to open into 
the right innominate vein, 
just at its junction with the 
superior vena cava. The thy- 
roidea ima vein (v. thyreoidea 
ima} passes downward in 
front of the trachea and ter- 
minates in the left innominate 
vein. These veins receive 
tributaries from the tracheal 
veins(vv.tracheales}, from the 
oesophageal veins (vv.eesopha- 
gea}, from the inferior larjm- 
gQ&\vein(v.laryngea inferior}. 
,Anterior jugular. 
Superior thyroid. 
-External jugular. 
Middle thyroid. 
Mediastinal 
and 
pericardiac. 
Phrenic. 
Suprarenal. 
■Suprarenal. 
Fig. 464.-The venae cavae and azygos veins, with their formative 
branches. 752 
THE BLOOD-VASCULAR SYSTEM 
The Intercostal Veins (w. intercostales) are divided into anterior and posterior 
intercostals. 
The Anterior Intercostal Veins are tributaries of the internal mammary or the 
musculo-phrenic veins (p. 731). 
The Posterior Intercostal Veins (Fig. 464) number eleven on each side, there 
being one vein in each intercostal space. Each vein lies in the groove at the 
lower margin of the rib above the corresponding intercostal artery. On the right 
side the first posterior intercostal vein crosses the neck of the first rib anteriorly 
and opens into the vertebral vein or the innominate vein. The first posterior 
intercostal of the left side follows a like course, and empties into the vertebral 
or innominate vein. The posterior intercostals of the right side, from the fifth 
to the eleventh, inclusive, open individually into the vena azygos major. The 
left upper azygos vein receives the fifth, sixth, seventh, and eighth posterior 
intercostals of the left side. The left lower azygos vein receives the ninth, tenth, 
and eleventh left posterior intercostals. 
The Right Superior Intercostal Vein (v. intercostalis suprema dextra) is formed 
by the union of the second, third, and fourth right posterior intercostals. It 
passes downward and inward and opens into the vena azygos major. 
The Left Superior Intercostal Vein (v. intercostalis suprema sinister) runs across 
the transverse aorta and opens into the left innominate vein. It usually receives 
the left bronchial and left superior phrenic vein, and communicates below with 
the vena azygos minor superior. Each posterior intercostal vein obtains branches 
from the ribs and muscles and also a dorsal branch, which receives blood from the 
muscles of the back, from in front of the vertebral bodies, from back of the ver- 
tebral arches, and from the spinal canal by way of a vein which passes through 
the intervertebral foramen. 
The Superior Vena Cava (v. cava superior) (Fig. 464) receives the blood 
which is conveyed to the heart from the whole of the upper half of the body. 
It is a short trunk, varying from two inches and a half to three inches in length, 
formed by the junction of the two innominate veins. It commences immediately 
below the cartilage of the first rib close to the sternum on the right side, and, 
descending vertically, enters the pericardium about an inch and a half above the 
heart, and terminates in the upper part of the right auricle opposite the upper 
border of the third right costal cartilage. In its course it describes a slight curve, 
the convexity of which is turned to the right side. 
Relations.-In front, with the pericardium and process of cervical fascia which 
is continuous with it: this separates it from the thymus gland and from the ster- 
num; behind, with the root of the right lung; on its right side, with the phrenic 
nerve and right pleura; on its left side, with the commencement of the innominate 
artery and ascending part of the aorta. The portion contained within the peri- 
cardium is covered by the serous layer of that membrane in its anterior three- 
fourths. It receives the vena azygos major just before it enters the pericardium, 
and several small veins from the pericardium and parts in the mediastinum. 'The 
superior vena cava has no valves. 
The Azygos Veins connect together the superior and inferior venue cavse, 
taking the place of those vessels in that part of the chest occupied by the heart. 
The Larger or Right Azygos Vein or the Vena Azygos Major (v. azygos) (Fig. 464) 
commences opposite the first or second lumbar vertebra by a branch from the right 
lumbar veins, called the right ascending lumbar vein (y. lumbalis ascendens dextra); 
sometimes by a branch from the right renal vein or from the inferior vena cava. It 
enters the thorax through the aortic opening in the Diaphragm, and passes along 
the right side of the vertebral column to the fourth dorsal vertebra, where it 
arches forward over the root of the right lung, and terminates in the superior vena 
cava just before that vessel enters the pericardium. Whilst passing through the THE SPINAL VEINS 
753 
aortic opening of the Diaphragm it lies with the thoracic duct on the right side 
of the aorta, and in the thorax it lies upon the intercostal arteries on the right 
side of the aorta and thoracic duct, and is partly covered by pleura. 
Tributaries.-It receives the lower ten posterior intercostal veins of the right side, 
the upper two or three of these opening first of all into the right superior intercostal 
vein. It receives the azygos minor veins, several oesophageal, mediastinal, and 
pericardial veins; near its termination, the right bronchial vein; and generally 
the right superior intercostal vein. A few imperfect valves are found in this vein; 
but its tributaries are provided with complete valves. 
The intercostal veins on the left side, below the three upper intercostal spaces, 
usually form two trunks, named the left lower and the left upper azygos veins. 
The Left Lower or Smaller Azygos Vein or the Vena Azygos Minor (v. hemiazygos') 
(Fig. 464) commences in the lumbar region by a branch from one of the lumbar 
veins, ascending lumbar (v. lumbalis ascendens), or from the left renal. It passes 
into the thorax through the left crus of the Diaphragm, and, descending on the 
left side of the spine as high as the ninth dorsal vertebra, passes across the 
column, behind the aorta and thoracic duct, to terminate in the right azygos vein. 
It receives the four or five lower intercostal veins of the left side, and some 
(esophageal and mediastinal veins. 
The Left Upper Azygos Vein (v. hemiazygos accessoria) varies inversely with the 
size of the left superior intercostal. It receives veins from the intercostal spaces 
between the left superior intercostal vein and highest tributary of the left lower 
azygos. They are usually three or four in number, usually the fourth, fifth, sixth, 
and seventh left posterior intercostal veins. They join to form a trunk which ends 
in the right azygos vein or in the left lower azygos. It sometimes receives the left 
bronchial vein. When this vein is small or altogether wanting, the left superior 
intercostal vein will extend as low as the fifth or sixth intercostal space. 
Surgical Anatomy. -In obstruction of the inferior vena cava the azygos veins are one of the 
principal means by which the venous circulation is carried on, connecting as they do the superior 
and inferior venae cavse, and communicating with the common iliac veins by the ascending lum- 
bar veins, and with many of the tributaries of the inferior vena cava. 
The Bronchial Veins (vv. bronchioles) return the blood from the substance of 
the lungs, except from the smaller bronchial tubes and alveola. The blood from 
them is received by the pulmonary veins. The bronchial vein of the right side 
opens into the vena azygos major near its termination. The bronchial vein of 
the left side opens into the left superior intercostal vein or the left upper azygos 
vein. The bronchial veins are joined by veins from the trachea and medias- 
tinum. 
The Spinal Veins. 
The numerous venous plexuses placed upon and within the spine may be 
arranged into four sets: 
1. Those placed on the exterior of the spinal column, the dorsi-spinal veins. 
2. Those situated in the interior of the spinal canal, between the vertebrae and 
the theca vertebralis, meningo-rachidian veins. 
3. The veins of the bodies of the vertebra?, venae basis vertebrarum. 
4. The veins of the spinal cord, medulli-spinal veins. 
1. The Dorsi-spinal Veins (plexus venosi vertebrates externi) commence by 
small branches which receive their blood from the integument of the back of the 
spine and from the muscles in the vertebral grooves. They constitute two plexuses: 
an anterior plexus (plexus venosi vertebrales anteriores) upon the vertebral bodies 
and a posterior plexus (plexus venosi vertebrales posteriores), which surrounds the 
spinous processes, the laminae, and the transverse and articular processes of 754 
THE BLOOD-VASCULAR SYSTEM 
all the vertebrae. At the bases of the transverse processes they communicate, by 
means of ascending and descending branches, with the veins surrounding the 
contiguous vertebrae, and they join with the veins in the spinal canal by branches 
which perforate the ligamenta subflava. Other branches pass obliquely forward, 
between the transverse processes, and communicate with the intraspinal veins 
through the intervertebral foramina (vv. intervertebrales'). The dorsi-spinal veins 
terminate by joining the vertebral veins in the neck, the intercostal veins in the 
thorax, and the lumbar and sacral veins in the loins and pelvis. 
The dorsi-spinal veins. 
Fig. 465.-Transverse section of a dorsal vertebra, showing the spinal veins. 
2. The Meningo-rachidian Veins (plexus venosi vertebrates interni).-The 
principal veins contained in the spinal canal are situated between the theca verte- 
bralis and the vertebrae. They consist of two longitudinal plexuses, one of which 
runs along the posterior surface of the bodies of the vertebrae, anterior longitudinal 
spinal veins. The other plexus, posterior longitudinal spinal veins, is placed on the 
inner or anterior surface of the laminae of the vertebrae. 
Fig. 466.-Vertical section of two dorsal vertebrae, showing the spinal veins. 
The Anterior Longitudinal Spinal Veins (sinus vertebrates longitudinales} consist 
of two large, tortuous veins which extend along the whole length of the vertebral 
column, from the foramen magnum, where they communicate by a venous ring 
around that opening, to the base of the coccyx, being placed one on each side of 
the posterior surface of the bodies of the vertebrae along the margin of the posterior 
common ligament. These veins communicate together opposite each vertebra by VEINS OF LOWER EXTREMITY, ABDOMEN AND PELVIS 
755 
transverse trunks which pass beneath the ligament. Each transverse trunk 
receives the large vena basis vertebrae (v. basivertebralis) from the interior of the 
body of the vertebra. The anterior longitudinal spinal veins are least developed 
in the cervical and sacral regions. They are not of uniform size throughout, 
being alternately enlarged and constricted. At the intervertebral foramina they 
communicate with the dorsi-spinal veins, and with the vertebral veins in the neck, 
with the intercostal veins in the dorsal region, and with the lumbar and sacral 
veins in the corresponding regions. 
The Posterior Longitudinal Spinal Veins, smaller than the anterior, are situated 
one on each side, between the inner surface of the laminae and the theca verte- 
bralis. They communicate (like the anterior) opposite each vertebra by trans- 
verse trunks, and with the anterior longitudinal veins by lateral transverse branches 
which pass from behind forward. The posterior longitudinal veins, by branches 
which perforate the ligamenta subflava, join with the dorsi-spinal veins. From 
them branches are given off which pass through the intervertebral foramina and 
join the vertebral, intercostal, lumbar, and sacral veins. The anterior and pos- 
terior longitudinal spinal veins join by numerous branches and really constitute 
one plexus, the plexus venosi vertebrates interni. 
The Intervertebral Veins (w. intervertebrales) accompany the spinal nerves 
in the intervertebral foramina, receive veins from the spinal cord, and join the 
meningo-rachidian and the dorsi-spinal veins. 
3. The Veins of the Bodies of the Vertebrae or the Venae Basis Vertebrarum 
(vv. basivertebrales) emerge from the foramen on the posterior surface of each 
vertebra and join the transverse trunk connecting the anterior longitudinal spinal 
veins. They are contained in large, tortuous channels in the substance of the 
bones, similar in every respect to those found in the diploe of the cranial bones. 
These canals lie parallel to the upper and lower surface of the bones. They com- 
mence by small openings on the front and sides of the bodies of the vertebrae, 
through which communicating branches from the veins external to the bone pass 
into its substance, and converge to the principal canal, which is sometimes double 
toward its posterior part. They open into the corresponding transverse branch unit- 
ing the anterior longitudinal veins. They become greatly developed in advanced age. 
4. The Veins of the Spinal Cord or the Medulli-spinal Veins (vv. spinales') 
emerge from the cord substance and enter the pia mater plexus. The pia mater 
plexus is a minute, tortuous, venous plexus which covers the entire surface of the 
cord, being situated between the pia mater and arachnoid. "In this plexus there 
are six longitudinal channels-one antero-median, along the anterior fissure- 
two antero-lateral, immediately behind the anterior nerve roots-two postero- 
lateral, immediately behind the posterior nerve roots-and one postero-median, 
over the postero-septum."1 These vessels are largest in the lumbar region. 
Near the base of the skull they unite and form two or three small trunks, which 
communicate with the vertebral veins, and terminate in the inferior cerebellar 
veins or in the inferior petrosal sinuses. Each of the spinal nerves is accompanied 
by a branch as far as the intervertebral foramina, where it joins the other veins 
from the spinal canal. 
There are no valves in the spinal veins. 
VEINS OF THE LOWER EXTREMITY, ABDOMEN, AND PELVIS 
(Figs. 467, 468). 
The Veins of the Lower Extremity are subdivided, like those of the upper, 
into two sets, superficial and deep, the superficial veins being placed beneath the 
1 D. J. Cunningham. A Text-book of Anatomy. THE BLOOD-VASCULAR SYSTEM 
756 
integument, between the two layers of superficial fascia, the deep veins accom- 
panying the arteries, and forming the vense comites of those vessels. Both sets 
of veins are provided with valves, which are more numerous in the deep than in 
the superficial set. These valves are also more numerous in the lower than in 
the upper limb. 
The Superficial Veins of the Lower Extremity 
The Superficial Veins of the Foot.-On the sole of the foot there is a sub- 
cutaneous venous plexus (rete venosum planfare cutaneum), from which some 
branches go to the deep veins, but most of the branches pass around the margins 
to the dorsum of the foot. There is a transverse venous arch at the root of the 
toes which receives plantar vessels from the toes and sends branches between the 
toes (w. intercapitulares) to the venous arch of the dorsum. On the dorsum of each 
toe the veins gather into two vessels, known as the dorsal digital veins (yv. digitales 
pedis dorsales). The dorsal digital veins from the opposed margins of two toes 
unite to form a dorsal interdigital vein. There are four dorsal interdigital veins 
(yv. digitales communes pedis), and they pass into the venous arch of the dorsum. 
The dorsal digital vein, from the inner surface of the great toe, passes directly 
into the internal saphenous vein, and the dorsal digital vein, from the outer 
surface of the little toe, passes directly into the external saphenous vein. 
On the dorsum of the foot is a venous arch (arcus venosus dorsalis pedis 
[cutaneus\), situated in the superficial structures over the anterior extremities of 
the metatarsal bones. It has its convexity directed forward, and receives digital 
tributaries from the upper surface of the toes; at its concavity it is joined by 
numerous small veins which form a plexus on the dorsum of the foot (rete 
venosum dorsale pedis cutaneum). The arch terminates internally in the long 
saphenous, externally in the short saphenous vein. 
The chief superficial veins of the lower extremity are the internal or long saphenous 
and the external or short saphenous. 
The Internal or Long Saphenous Vein (y. saphena magna) (Figs. 467 and 470) 
commences at the inner side of the arch on the dorsum of the foot; it ascends in front 
of the inner malleolus and along the inner side of the leg, behind the inner margin 
of the tibia, accompanied by the internal saphenous nerve. At the knee it passes 
backward behind the inner condyle of the femur, ascends along the inside of the 
thigh, and, passing through the saphenous opening in the fascia lata, terminates 
in the femoral vein about an inch and a half below Poupart's ligament. This vein 
receives in its course cutaneous tributaries from the leg and thigh, and at the 
saphenous opening receives the superficial epigastric, superficial circumflex iliac, 
and external pudic veins. The veins from the inner and back part of the thigh 
frequently unite to form a large vessel, which enters the main trunk near the 
saphenous opening; and sometimes those on the outer side of the thigh join to form 
another large vessel; so that occasionally three large veins are seen converging from 
different parts of the thigh toward the saphenous opening. The internal saphenous 
vein communicates in the foot with the internal plantar vein; in the leg, with the 
posterior tibial veins by branches which perforate the tibial origin of the Soleus 
muscle, and also with the anterior tibial veins; at the knee, with the articular 
veins; in the thigh, with the femoral vein by one or more branches. The valves 
in this vein vary from two to six in number; they are more numerous in the thigh 
than in the leg. 
The External or Short Saphenous Vein (v. saphena parva) (Fig. 468) com- 
mences at the outer side of the arch on the dorsum of the foot; it ascends behind the 
outer malleolus, and along the outer border of the tendo Achillis, across which it 
passes at an acute angle to reach the middle line of the posterior aspect of the leg. THE SUPERFICIAL VEINS OF THE LOWER EXTREMITY 
757 
Passing directly upward, it perforates the deep fascia in the lower part of the 
popliteal space, and terminates in the popliteal vein, between the heads of the 
Fig. 468.-External or short saphenous vein. 
Gastrocnemius muscle.1 It receives numerous large 
tributaries from the back part of the leg, and com- 
municates with the deep veins on the dorsum of the 
foot and behind the outer malleolus. Before it per- 
forates the deep fascia it gives off a communicating 
branch, which passes upward and inward to join the 
internal saphenous vein. This vein has a variable 
number of valves, from three to nine (Gay), one of 
which is always found near its termination in the 
popliteal vein. The external saphenous nerve lies 
close beside this vein. 
Surgical Anatomy.-The saphenous veins are of consider- 
able surgical importance, since a varicose condition of these 
vessels is more frequently met with than of those in other parts 
Fig. 467. - The internal or long 
saphenous vein and its branches. 
1 Mr. Gay calls attention to the fact that the external saphenous vein often (he says invariably) penetrates 
the fascia at or about the point where the tendon of the Gastrocnemius commences, and runs below the fascia 
in the rest of its course, or sometimes among the muscular fibres, to join the popliteal vein. (See Gay on Vari- 
cose Disease of the Lower Extremities, p. 24, where there is also a careful and elaborate description of the 
branches of the saphena veins.)-Ed. of 15th English edition. 758 
THE BLOOD- VASCULAR SYSTEM 
of the body, except perhaps the spermatic and hemorrhoidal veins. The course of the internal 
saphenous is in front of the tip of the inner malleolus, over the subcutaneous surface of the lower 
end of the tibia, and then along the internal border of this bone to the back part of the internal 
condyle of the femur, whence it follows the course of the Sartorius muscle, and is represented on 
the surface by a line drawn from the posterior border of the Sartorius on a level with the internal 
condyle to the saphenous opening. The external saphenous lies behind the external malleolus, 
and from this follows the middle line of the calf to just below the ham. It is not generally so 
apparent beneath the skin as the internal saphenous. Both these veins in the leg are accom- 
panied by nerves, the internal saphenous being joined by its companion nerve just below the 
level of the knee-joint. No doubt much of the pain of varicose veins in the leg is due to this 
fact. 
The Deep Veins of the Lower Extremity. 
The deep veins of the lower extremity accompany the arteries and their branches 
and are called the venae comites of those vessels. The venae comites in the lower 
extremity pass into one trunk, the popliteal vein, 
whereas in the upper extremity the venae comites con- 
tinue with the artery to the axilla. 
The Deep Veins of the Foot.-The plantar digital 
veins (w. digitales plantares) form the plantar metatarsal 
veins (wx metatar sea plantares), which communicate1 
with the veins of the dorsum of the foot by perfor- 
ating veins and also communicate with the deep venous 
arch of the sole of the foot (arcus venosus plantaris pro- 
fundus). The plantar arch gives off lateral or external 
plantar veins, which unite with median or internal plantar 
veins to form the posterior tibial veins. On the dorsum 
of the foot the deep veins begin as the dorsal metatarsal 
veins (vv. metatarseoe dorsales pedis), which form the 
venae comites of the dorsalis pedis artery. 
'The Posterior Tibial Veins (vv. tibiedes posteriores) 
accompany the posterior tibial artery and are joined 
by the peroneal veins. 
The Anterior Tibial Veins (vv. tibiales anteriores) 
are formed by a continuation upward of the venae 
comites of the dorsalis pedis artery. They pass be- 
tween the tibia and fibula, through the large oval aper- 
ture above the interosseous membrane, and form, by 
their junction with the posterior tibial, the popliteal 
vein. 
The valves in the deep veins are very numerous. 
The Popliteal Vein (v. poplitea) (Fig. 469) is formed 
by the junction of the anterior and posterior tibial 
veins; it ascends through the popliteal space to the 
aperture in the Adductor magnus, where it becomes the femoral vein. In the 
lower part of its course it is placed internal to the artery; between the heads of 
the Gastrocnemius it is superficial to that vessel; but above the knee-joint it is 
close to the outer side of the artery. It receives the sural veins from the Gastroc- 
nemius muscle, the articular veins, and the external saphenous vein. The valves 
in this vein are usually four in number. 
The Femoral Vein (v. jemoralis) (Figs. 470 and 471) accompanies the femoral 
artery through the upper two-thirds of the thigh. In the lower part of its course 
it lies external to the artery; higher up it is behind it; and at Poupart's ligament 
it lies to its inner side and on the same plane. It receives numerous muscular 
tributaries, and about an inch and a half below Poupart's ligament it is joined by 
Fig. 469.-The popliteal vein. 
(Poirier and Charpy.) THE DEEP VEINS OF THE LOWER EXTREMITY 
759 
the profunda femoris (v. profunda femoris)', near its termination it is joined by 
the internal saphenous vein. The valves in this vein are four or five in number. 
The External Iliac Vein (v. iliaca externa) (Figs. 464, 471, and 473) commences 
at the termination of the femoral, beneath the crural arch, and, passing upward 
along the brim of the pelvis, terminates opposite the sacro-iliac synchondrosis by 
uniting with the internal iliac to form the common iliac vein. On the right side it 
lies at first along the inner side of the external iliac artery, but as it passes upward 
gradually inclines behind it. On the left side it lies altogether on the inner side 
of the artery. It receives, immediately above Poupart's ligament, the deep epi- 
UMBILICUS 
SUPERFICIAL 
EPIGASTRIC 
SUPERFICIAL 
EXTERNAL 
CIRCUMFLEX 
SUPERFICIAL 
INTERNAL- 
CIRCUMFLEX 
SUPERFICIAL 
EXTERNAL, 
PUDIC. 
Fig. 470.-The femoral vein and its tributaries. (Poirier and Charpy.) 
gastric and deep circumflex iliac veins and a small pubic vein, corresponding to 
the pubic branch of the obturator artery. According to Friedreich, it frequently 
contains one and sometimes two valves. 
The Deep Epigastric Vein (v. epigastrica inferior) (Fig. 471).-Two veins 
accompany the deep epigastric artery; they usually unite into a single trunk 
before their termination in the external iliac vein. 
The Deep Circumflex Iliac Vein (v. circumflexa ilium profunda) (Fig. 471).- 
Two veins accompany the deep circumflex iliac artery. These unite into a single 
trunk which crosses the external iliac artery just above Poupart's ligament and 
terminates in the external iliac vein. 760 
THE BLOOD-VASCULAR SYSTEM 
The Hypogastric or Internal Iliac Vein (v. iliaca interna or v. hypogastrica) 
(Figs. 464, 471, and 473) is formed by the veins corresponding to all the branches 
of the internal iliac artery except the umbilical branch. It receives the blood 
from the exterior of the pelvis by the gluteal, sciatic, internal pudic, and obturator 
veins, and from the organs in the cavity of the pelvis by the middle hemor- 
rhoidal veins, the superior vesical plexus and the prostatico-vesical plexus in the 
male, and the superior vesical, inferior vesical, uterine and vaginal plexuses in 
the female. The vessels forming these plexuses are remarkable for their large size, 
their frequent anastomoses, and the number of valves which they contain. The 
internal iliac vein lies at first on the inner side, and then behind the internal iliac 
artery, and terminates opposite the sacro-iliac articulation by uniting with the 
external iliac to form the common iliac vein. This vessel has no valves. 
The Internal Pudic Veins (vv. pudenda; internes') (Fig. 471) have the same course as 
the internal pudic artery. They receive tributaries corresponding to the branches 
of the artery, except the tributary corresponding to the dorsal artery of the 
penis; that is, the deep dorsal vein of the penis, which opens into the prostatico- 
vesical plexus. 
CIRCUMFLEX 
ILIAC 
DEEP 
EPIGASTRIC 
LATERAL^ 
sacral" 
MIDDLE 
SACRAL 
Fig. 471.-The iliac veins. (Poirier and Charpy.) 
The Inferior or External Hsemorrhoidal Veins (Figs. 472 and 473) collect blood 
from the anus. They pass outward over the External sphincter muscle, unite with 
numerous subcutaneous veins, and form larger vessels which join the internal 
pudic veins. 
The Middle Haemorrhoidal Veins (Figs. 472 and 473) help to form the hemor- 
rhoidal plexus, perforate the rectal wall, and empty into the internal iliac vein. 
These veins, by their anastomoses in the hemorrhoidal plexus, establish a 
communication between the portal and systemic venous systems. 
The Lateral Sacral Veins.(vu sacrales laterales) (Fig. 471) accompany the lateral 
sacral arteries and terminate in the internal iliac vein. THE DEEP VEINS OF THE LOWER EXTREMITY 
761 
Surgical Anatomy.-The veins of the hemorrhoidal plexus are apt to become dilated and 
varicose, and form piles, hemorrhoids. This is due to several anatomical reasons: the vessels are 
contained in very loose, or connective tissue, so that they obtain less support from surrounding 
structures than most other veins, and are less capable of resisting increased blood pressure: 
the condition is favored by gravitation, being influenced by the erect posture, either sitting or 
standing, and by the fact that the superior hemorrhoidal and portal veins have no valves. The 
veins pass through muscular tissue and are liable to be compressed by its contraction, especially 
during the act of defecation, and they are affected by every form of portal obstruction. 
The Obturator Vein (v. obturatorice) (Figs. 471 and 473) follows the course of 
the obturator artery, lying below the artery as it passes over the side of the 
pelvis; this vein empties into the front part of the internal iliac vein. 
The Sciatic Veins are two in number; they accompany the sciatic artery in 
the upper part of the back of the thigh, and just before their termination in the 
internal iliac the two veins unite. 
The Gluteal Veins (w. glutea) are usually two in number, and return to the 
internal iliac vein the blood that has been distributed by the gluteal artery and 
its branches. 
SUPERIOR 
'HEMORRHOIDAL 
MIDDLE 
hemorrhoidal' 
.MIDDLE 
SACRAL 
INFERIOR. 
HEMORRHOIDAL 
Fig. 472.-Scheme of the anastomosis of the veins of the rectum. (Poirier and Charpy.) 
The Superior Vesical Plexus {Fig. 473) is placed upon the fundus and 
lateral aspects of the bladder on the external aspect of the muscular coat. It 
receives vessels from the mucous membrane and from the muscular walls. It 
empties into the internal pudic vein: in the male it communicates with the 
prostatico-vesical plexus, and in the female with the inferior vesical plexus. 
The Prostatic or the Prostatico-vesical Plexus (Fig. 473) surrounds the 
prostate gland and the neck of the bladder. It is contained between the recto- 
vesical fascia which surrounds the base and sides of the gland and the true capsule 
of the gland. It communicates with the superior vesical plexus behind and 
above, and receives the deep dorsal vein of the penis, which enters the pelvis 
between the subpubic and triangular ligaments. This plexus receives veins from 
the seminal vesicles and vasa deferentia. On each side one or more vessels pass THE BLOOD-VASCULAR SYSTEM 
762 
from the prostatico-vesical plexus to the internal iliac vein. The veins composing 
the prostatic plexus are very liable to become varicose, and often contain hard, 
earthy concretions called phleboliths. 
The Inferior Vesical Plexus exists only in the female, and corresponds to the 
prostatico-vesical plexus in the male, and surrounds the neck of the bladder and 
the upper portion of the urethra. It receives the dorsal vein of the clitoris and 
sends efferents to the internal iliac vein. 
THIRD LUMBAR 
SPERMATIC 
SUPERIOR 
HEMORRHOIDAL 
DEEP, 
circumflex' 
ILIAC 
OBTURATOR 
HEMORRHOIDAL 
PLEXUS 
PROSTATIC 
PLEXUS 
M IDDLE 
HEMORRHOIDAL 
INFERIOR 
HEMORRHOIDAL 
DORSAL VEIN 
OF PENIS 
SCROTAL 
VESICAL PLEXUS 
INTERNAL PUDIC 
Fig. 473.-The veins of the male pelvis, right half, viewed from the left. The psoas muscle has been removed 
and the rectum drawn down somewhat to the side. (Spalteholz.) 
Surgical Anatomy.-The prostatico-vesical plexus is wounded in the lateral operation of 
lithotomy, and it is through it that septic matter finds its way into the general circulation after 
this operation. In enucleating the prostate the gland is shelled out from its capsule of recto- 
vesical fascia. The veins of the plexus remain attached to the sheath. 
The Dorsal Veins of the Penis.-The Superficial Dorsal Vein of the Penis (Fig- 
474) receives blood from the prepuce and runs backward beneath the skin, and 
divides into two branches which terminate in the superficial external pudic vein. 
The Deep Dorsal Vein of the Penis (y. dorsalis penis) (Figs. 473 and 474) is a vessel 
of large size which returns the blood from the body of that organ. At first it con- THE DEEP VEINS OF THE LOWER EXTREMITY 
763 
sists of two branches, which are contained in the groove on the dorsum of the penis, 
and it receives numerous superficial veins and veins from the glans penis and the 
corpus spongiosum. These vessels unite into a single trunk, which passes between 
the two parts of the suspensory ligament of the penis, and through an aperture 
between the subpubic ligament and 
the apex of the triangular ligament, 
and divides into two branches, which 
enter the prostatico-vesical plexus. 
The dorsal vein of the clitoris corre- 
sponds in woman to the dorsal vein 
of the penis in man, and runs into 
the inferior vesical plexus. 
The Vaginal Plexuses and Veins 
(Fig. 475).-The vaginal plexuses are 
placed at the sides of the vagina, being 
especially developed at the orifice of 
the canal. They receive vessels from 
the vaginal walls. The plexuses 
communicate with the uterine plexus above, with the bulbar veins below, with 
the inferior vesical plexus in front and with the hemorrhoidal plexus behind. 
From the upper part of each vaginal plexus comes a vaginal vein which passes 
to the internal iliac. 
The Uterine Plexuses (Fig. 475) are situated along the sides and superior angles 
of the uterus, between the layers of the broad ligament. They receive the veins 
from the uterus, which veins are without valves. During pregnancy these veins 
SUPERFICIAL DOR- 
SAL VEIN 
CORPUS CAVERNOSUM 
DORSAL ARTERY 
.DEEP DORSAL VEIN 
SKIN- 
AREOLAR 
' TISSUE 
CAVERNOUS. 
ARTERY 
DARTOS- 
DEEP 
FASCIA 
BULBO-CAVERNOUS ARTERY, 
- ANTERIOR BRANCH 
URETHRA 
Fig. 474.-The penis in transverse section, showing the 
blood-vessels. (Testut.) 
CORPUS 
SPONGIOSUM 
TUBAL VESSELS 
ANASTOMOSIS OF 
UTE R I N E AND 
OVARIAN ARTERIES 
FALLOPIAN 
TUBE 
HELICINE BRANCHES 
UTERO- 
SACRAL 
LIGA- 
MENT 
-ROUND LIGAMENT 
UTERINE VENOUS PLEXUS/ 
URETER 
UTERINE^ 
VEINS 
^UTERINE ARTERY 
VAGINAL VENOUS PLEXUS 
SUPERIOR VAGINAL 
ARTERIES 
Fig. 475.-Vessels of the uterus and its appendages, rear view. (Testut.) 
OS UTERI 
VAGINA CUT OPEN BEHIND 
become large venous canals known as the uterine sinuses, and bring blood from the 
substance of the placenta. These veins join the ovarian above and the vaginal 
below, and anastomose with each other. They are not tortuous like the artery. 
The Uterine Veins (vv. uterine?) (Fig. 475) arise from the lower part of the 
plexus, and there are usually two veins on each side and they are without valves. 
These veins for the first portion of their course are placed in the base and inner 
portion of the broad ligament; they then pass back with the uterine artery in a 
peritoneal fold between the back of the broad ligament and the recto-uterine 
fold (Cunningham); they then pass upward and enter the internal iliac vein. 764 
THE BLOOD-VASCULAR SYSTEM 
The Common Iliac Vein (v. iliaca communis) (Figs. 464, 471, and 473) on 
each side is formed by the union of the external and internal iliac veins in 
front of the sacro-iliac articulation: passing obliquely upward toward the right 
side, each vein terminates upon the intervertebral substance between the fourth 
and fifth lumbar vertebrae, where the veins of the two sides unite at an acute 
angle to form the inferior vena cava. The right common iliac (y. iliaca communis 
dextra) is shorter than the left, nearly vertical in its direction, and ascends behind 
and then to the outer side of its corresponding artery. The left common iliac 
(y. iliaca communis sinistra), longer and more oblique in its course, is at first 
situated on the inner side of the corresponding artery, and then behind the right 
common iliac. Each common iliac receives the ilio-lumbar, and sometimes the 
lateral sacral, veins. The left receives, in addition, the middle sacral vein. No 
valves are found in these veins. 
The Middle Sacral Veins (Figs. 471 and 472) accompany the corresponding 
artery along the front of the sacrum, and join to form a single vein (y. sacralis 
media), which terminates in the left common iliac vein; occasionally in the angle 
of junction of the two iliac veins. The middle sacral veins communicate with 
the inferior hemorrhoidal. 
The Ilio-lumbar Veins (yv. iliolumbales) receive branches from the iliac fossae, 
spinal muscles, and spinal canal. One vein on each side runs with the artery, 
passes posterior to the psoas muscle, and joins the common iliac vein. 
Peculiarities.-The left common iliac vein, instead of joining with the right in its usual 
position, occasionally ascends on the left side of the aorta as high as the kidney, where, after 
receiving the left renal vein, it crosses over the aorta, and then joins with the right vein to form 
the vena cava. In these cases the two common iliacs are connected by a small communicating 
branch at the spot where they are usually united.1 
The Ascending or Inferior Vena Cava (y. cava inferior) (Figs. 464 and 471) 
returns to the heart the blood from all the parts below the Diaphragm. It is 
formed by the junction of the two common iliac veins on the right side of the 
intervertebral substance between the fourth and fifth lumbar vertebrae. It passes 
upward along the front of the spine on the right side of the aorta, and, having reached 
the under surface of the liver, is contained in a groove on its posterior surface. It 
then perforates the central tendon of the Diaphragm, enters the pericardium, 
where it is covered for a very short distance by the serous layer of the pericardium, 
and terminates in the lower and back part of the right auricle. At its termination 
in the auricle it is provided with a valve, the Eustachian valve (valvula v. cavce 
[inferiorisEustachii]), which is of large size during foetal life. 
Relations.-In front, from below upward, with the mesentery, right spermatic 
artery, transverse portion of the duodenum, the pancreas, portal vein, and the 
posterior surface of the liver, which, in most cases, partly and occasionally com- 
pletely surrounds it; behind, with the vertebral column, the right crus of the 
Diaphragm, the right renal and lumbar arteries, and the right semilunar ganglion; 
on the left side, with the aorta. 
Peculiarities. In Position.-This vessel is sometimes placed on the left side of the aorta, 
as high as the left renal veins, after receiving which it crosses over to its usual position on the 
right side; or it may be placed altogether on the left side of the aorta, as far upward as its ter- 
mination in the heart: in such cases the abdominal and thoracic viscera, together with the great 
vessels, are all transposed. 
Point of Termination.-Occasionally the inferior vena cava joins the right azygos vein, 
which is then of large size. In such cases the superior cava receives the whole of the blood 
from the body before transmitting it to the right auricle, except the blood from the hepatic veins, 
which passes directly into the right auricle. 
1 See two cases which have been described by Mr. Walsham in the St. Bartholomew's Hospital Reports, 
vols. xvi. and xvii.-Ed. of 15th English edition. THE DEEP VEINS OF THE LOWER EXTREMITY 
765 
Tributaries.-It receives in its course the following veins: 
Lumbar. 
Right Spermatic. 
Renal. 
Suprarenal. 
Phrenic. 
Hepatic. 
The Lumbar Veins (vv. lumbales), four in number on each side, collect the 
blood by dorsal tributaries from the muscles and integument of the loins and by 
abdominal tributaries from the walls of the abdomen, where they communicate 
with the epigastric veins. At the spine they receive veins from the spinal plexuses, 
and then pass forward, round the sides of the bodies of the vertebrae beneath the 
Fig. 476.-Spermatic veins. (Testut.) 
Psoas magnus muscle, and terminate at the back part of the inferior cava. The 
left lumbar veins are longer than the right, and pass behind the aorta. The lumbar 
veins of a side are connected together by a longitudinal vein which passes in front 
of the transverse processes of the lumbar vertebrae, and is called the ascending 
lumbar vein (v. lumbalis ascendent) (Fig. 464). It forms the most frequent origin 
of the corresponding vena azygos, and serves to connect the common iliac, ilio- 
lumbar, lumbar, and azygos veins of the corresponding side of the body. 
The Spermatic Veins (w. spermatictF (Fig. 476) emerge from the back of the testis, 
and receive tributaries from the epididymis; they unite and form a convoluted 
plexus called the spermatic plexus (plexus pampiniformis), which forms the chief THE BLOOD-VASCULAR SYSTEM 
766 
mass of the cord: the vessels composing this plexus are very numerous, and ascend 
along the cord in front of the vas deferens; below the external abdominal ring they 
unite to form three or four veins, which pass along the inguinal canal, and, enter- 
ing the abdomen through the internal abdominal ring, coalesce to form two veins, 
which ascend on the Psoas muscle behind the peritoneum, lying one on each side 
of the spermatic artery, and unite to form a single vein, which opens on the right 
side into the inferior vena cava at an acute angle; on the left side into the left renal 
vein at a right angle (Fig. 477). The termination of the left spermatic vein 
VENA 
CAVA 
SPERMATIC VEIN- 
RIGHT SIDE 
SPERMATIC VEIN - 
LEFT SIDE 
Fig. 477.-Terminations of the right and left spermatic veins. (Poirier and Charpy.) 
is called the emulgent vein. Professor John H. Brinton pointed out that a 
valve is usually absent in the emidgent vein (Fig. 478), but regularly present in 
the right spermatic vein.1 The left spermatic vein passes behind the sigmoid 
Hexure of the colon, and is thus exposed to pressure from the contents of that 
bowel. 
Surgical Anatomy.-The spermatic veins are very frequently varicose, constituting the dis- 
ease known as varicocele. Though it is quite possible that the originating cause of this affection 
may be a congenital abnormality either in the size or number of the veins of the pampiniform 
plexus, still it must be admitted that there are many anatomical reasons why these veins should 
become varicose-viz., the imperfect support afforded to them by the loose tissue of the scrotum; 
their great length; their vertical course; their dependent position; their plexiform arrangement 
in the scrotum, with their termination in one small vein in the abdomen; their few and imperfect 
valves; and the fact that they may be subjected to pressure in their passage through the abdominal 
wall. The left veins more often become varicose than the right veins, probably, as Brinton sug- 
gests, because the right spermatic vein practically always has a valve and opens into the vena 
cava at an acute angle, whereas the left spermatic vein is not unusually destitute of a valve at 
its opening and passes into the left renal vein at a right angle. 
The Ovarian Veins (vv. ovaricoe) (Fig. 475) are analogous to the spermatic in the 
male; they form a plexus near the ovary in the broad ligament and about the Fallo- 
pian tube, communicating with the uterine plexus. They terminate in the same way 
as the spermatic veins in the male. Valves are occasionally found in these veins. 
These vessels, like the uterine veins, become much enlarged during pregnancy. 
1 See John H. Brinton in the American Journal of the Medical Sciences, and also Handbuch der Topographi- 
schen Anatomie.von Joseph Hyrtl. Rivington maintains that a valve is usually found at the orifices of both the 
right and left spermatic veins. When no valves exist at the opening of the left spermatic vein into the left renal 
vein, valves are generally present in the left renal vein within a quarter of an inch from the orifice of the 
spermatic vein. (Journal of Anatomy and Physiology, vol. vii. p. 163).-Ed. of 15th English edition. THE DEEP VEINS OF THE LOWER EXTREMITY 
767 
The Renal Veins (w. renales) (Fig. 465) are of large size, and are placed in front 
of the renal arteries.1 The left is longer than the right, and passes in front of the 
aorta, just below the origin of the superior mesenteric artery. It receives the left 
spermatic, the left inferior, and, generally, the left suprarenal veins. It opens into 
the vena cava a little higher than the right. The utero-venous triangle of Byron 
Robinson is formed by the ureter, the renal veins, and the ovarian veins. 
The Suprarenal Veins (w. suprarenales) (Fig. 464) are two in number: that on 
the right side terminates in the vena cava; that on the left side, in the left renal 
or in the left phrenic vein. 
The Phrenic Veins (vv. phrenicoe) follow the course of the phrenic arteries. 
The two superior phrenic veins (vv. phrenicoe superior es), of small size, accom- 
pany the phrenic nerve and comes nervi phrenici artery, and join the internal 
mammary vein. The two inferior phrenic veins (w. phrenicoe injeriores) follow 
the course of the phrenic arteries, and terminate, the right in the inferior vena 
cava, the left in the left renal vein. 
Fig. 478.-Dissection of the vena cava, emulgent and spermatic veins, showing the right spermatic valve 
and its accompanying sinus, c, vena cava; e, emulgent vein; r, right spermatic vein; I, left spermatic vein; 
a, aperture by which the right spermatic vein empties into the vena cava; v, right spermatic valve; s, sinus 
across which the valve is stretched; f, termination of the left spermatic vein in the emulgent vein. (John H. 
Brinton.) 
The Hepatic Veins (w. hepaticoe) commence in the substance of the liver, in 
the capillary terminations of the portal vein and hepatic artery, intralobular veins: 
these tributaries, gradually uniting into sublobular veins; usually form three large 
hepatic veins, which converge toward the posterior surface of the liver and open 
into the inferior vena cava, whilst that vessel is situated in the groove at the back 
part of this organ. Of these three veins, one from the right and another from 
1 The student may observe that all veins above the Diaphragm, which do not lie on the same plane as the 
arteries which they accompany, lie in front of them, and that all veins below the Diaphragm, which do not 
lie on the same plane as the arteries which they accompany, lie behind them, except the renal and profunda 
femoris vein.- Ed. of 15th English edition. 768 
THE BLOOD-VASCULAR SYSTEM 
the left lobe open obliquely into the inferior vena cava, that from the middle of 
the organ and lobulus Spigelii having a straight course. The hepatic veins run 
singly, and are in direct contact with the hepatic tissue. They are destitute of 
valves. 
The Portal System of Veins (Fig. 479). 
The portal venous system is composed of four large veins which collect the venous 
blood from the viscera of digestion (stomach, intestine, and pancreas) and from 
the spleen. The trunk formed by their union, the Portal Vein {vena portce), 
enters the liver and ramifies throughout its substance after the manner of an 
artery and ends in capillaries, from which the blood is collected into the hepatic 
veins, which terminate in the inferior vena cava. The branches of this vein are 
in all cases single, and destitute of valves. 
The veins forming the portal system are-the 
Superior Mesenteric. 
Splenic. 
Inferior Mesenteric. 
Gastric. 
Cystic. 
The Superior Mesenteric Vein (v. mesenterica superior) (Fig. 479) returns the 
blood from the small intestines and from the caecum and ascending and transverse 
portions of the colon, corresponding with the distribution of the branches of the 
superior mesenteric artery. The large trunk formed by the union of these branches 
ascends along the right side and in front of the corresponding artery, passes in front 
of the transverse portion of the duodenum, and unites, behind the upper border 
of the pancreas, with the splenic vein to form the vena portae. It receives the 
right gastro-epiploic vein. The appendicular vein is a trilxitary of the superior 
mesenteric vein. 
The Splenic Vein (v. lienalis) (Fig. 479) commences by five or six large branches 
which return the blood from the substance of the spleen. These, uniting, form a 
single vessel, which passes from left to right, grooving the upper and back part of 
the pancreas below the artery, and terminates at its greater end by uniting at a 
right angle with the superior mesenteric to form the vena portae. The splenic vein 
is of large size, and not tortuous like the artery. It receives the vasa brevia from 
the left extremity of the stomach, the left gastro-epiploic vein, pancreatic branches 
from the pancreas, the pancreatico-duodenal vein, and the inferior mesenteric vein. 
The Inferior Mesenteric Vein (v. mesenterica inferior) (Fig. 479) returns the 
blood from the rectum, sigmoid flexure, and descending colon, corresponding with 
the ramifications of the branches of the inferior mesenteric artery. It lies to the left 
of the artery, and ascends beneath the peritoneum in the lumbar region; it passes 
behind the transverse portion of the duodenum and pancreas, and terminates 
in the splenic vein. Its hemorrhoidal branches, the superior haemorrhoidal veins, 
inosculate with the middle hemorrhoidal branches of the internal iliac, and thus 
establish a communication between the portal and the general venous system.1 
The Gastric Veins (vv. (jastricce) (Fig. 479) are two in number: one, a small vein, 
corresponds to the pyloric branch of the hepatic artery; the other, considerably 
larger, corresponds to the gastric artery. 'The former, the pyloric vein (v. pylorica), 
runs along the lesser curvature of the stomach toward the pyloric end, receives 
branches from the pylorus and duodenum, and ends in the vena portae. The 
latter, the gastric or coronary vein (v. coronaria ventriculi), begins near the pylorus, 
1 Besides this anastomosis between the portal vein and the branches of the vena cava, other anastomoses 
between the portal and systemic veins are formed by the communication between the gastric veins and the 
oesophageal veins, which empty themselves into the vena azygos minor; between the left renal vein and the 
veins of the intestines, especially of the colon and duodenum; between the veins of the round ligament of the 
liver and the portal veins; and between the superficial branches of the portal veins of the liver and the phrenic 
veins, as pointed out by Mr. Kiernan. (See Physiological Anatomy, by Todd and Bowman, 1859, vol. ii. p. 
348).-Ed. of 15th English edition. THE PORTAL SYSTEM OE VEINS 
769 
runs along the lesser curvature of the stomach toward the oesophageal opening 
in the diaphragm, and then passes across the front of the spine from left to right 
to end in the vena portse, at a point a little above the junction of the pyloric vein. 
The Cystic Vein (v. cystica) (Fig. 479).-The vena porta* generally receives the 
cystic vein, although that vessel sometimes terminates in the right branch of the 
vena porta*. 
Fig. 479.-Portal vein and its branches. 
Note.-In this diagram the right gastro-epiploic vein opens into the splenic vein; generally 
it empties itself into the superior mesenteric, close to its termination. 
The Portal Vein {vena portae} (Fig. 479) is formed by the junction of the superior 
mesenteric and splenic veins, their union taking place in front of the vena cava and 
behind the upper border of the head of the pancreas. Passing upward through 
the right border of the lesser omentum to the under surface of the liver, it enters 
the transverse fissure, where it is somewhat enlarged, forming the sinus of the 
portal vein, and divides into two branches which accompany the ramifications of 
the hepatic artery and hepatic duct throughout the substance of the liver. Of THE BLOOD-VASCULAR SYSTEM 
770 
these two branches, the right is the larger, but the shorter, of the two. The portal 
vein is about three or four inches in length, and, whilst contained in the lesser 
omentum, lies behind and between the common bile-duct and the hepatic artery, 
the former being to the right, the latter to the left. These structures are accom- 
panied by filaments of the hepatic plexus of nerves and numerous lymphatics, 
and are surrounded by a quantity of loose areolar tissue, the capsule of Glisson. 
The portal vein divides, in the substance of the liver, like an artery, and its 
minute ramifications end in capillaries, from which the blood is carried to the 
inferior vena cava by the hepatic veins; these veins also collect the blood which 
has been brought to the liver by the hepatic artery. It will therefore be seen 
that the blood which is carried to the liver by the portal vein passes through two 
sets of capillary vessels-viz.: (1) the capillaries in the stomach, intestine, pancreas, 
and spleen, and (2) the capillaries of the portal vein in the liver. 
THE CARDIAC VEINS (Fig. 480). 
The veins which return the blood from the substance of the heart are-the 
Great Cardiac Vein. 
Posterior Cardiac Vein. 
Left Cardiac Veins. 
Anterior Cardiac Veins. 
Right or Small Coronary Vein. 
Coronary Sinus. 
Venae Thebesii. 
The Great Cardiac or Left Coronary Vein (v. cordis magna) is a vessel of 
considerable size, which commences at the apex of the heart, and ascends along 
the anterior interventricular groove to the base of the ventricles. It then curves 
•VENA AZYGOS 
MAJOR 
LEFT AURICULAR. 
APPENDIX 
PULMONARY 
VEINS 
RIGHT CORONARY ARTERY 
.PULMONARY 
VEINS 
LEFT 
AURICLE 
AURICULAR-VENTRICULAR- 
GROOVE 
CORONARY. 
SINUS 
RIGHT 
AURICLE 
LEFT 
VENTRICLE 
POSTERIOR CARDIAC* 
VEIN 
POSTERIOR ; 
INTERVENTRIC- 
ULAR GROOVE 
rig'At coronary 
ARTERY-DESCEND- 
ING BRANCH 
Fig. 480.-Cardiac veins, dorsal view. (Testut.) 
'RIGHT 
VENTRICLE 
to the left side, around the auriculo-ventricular groove, between the left auricle 
and ventricle, to the back part of the heart, and opens into the left extremity 
of the coronary sinus, its aperture being guarded by two valves. It receives, in THE CARDIAC VEINS 
771 
its course, tributaries from both ventricles, but especially from the left, and also 
from the left auricle; one of these ascending along the thick margin of the left 
ventricle is of considerable size, and is called the left marginal vein. The vessels 
joining the great cardiac vein are provided with valves. 
The Posterior or Middle Cardiac Vein (y. cordis media) commences -by small 
tributaries, at the apex of the heart, communicating with those of the preceding. 
It ascends along the posterior interventricular groove to the base of the heart, 
and terminates in the coronary sinus, its orifice being guarded by a valve. It 
receives veins from the posterior surface of both ventricles. 
The Left Cardiac Vein (y. posterior ventriculi sinistri) receives three or four 
small vessels, which collect the blood from the posterior surface of the left ven- 
tricle. It opens into the lower border of the coronary sinus. 
The Anterior Cardiac Veins (yv. cordis anteriores) are three or four small 
vessels, which collect the blood from the anterior surface of the right ventricle. 
One of these, the vein of Galen, larger than the rest, runs along the right border 
of the heart. They open separately into the lower part of the right auricle. 
The Right Cardiac or Small Coronary Vein (y. cordis parva) runs along the 
groove between the right auricle and ventricle, to open into the right extremity of 
the coronary sinus. It receives blood from the back part of the right auricle and 
ventricle. 
The Coronary Sinus (sinus coronarius) is that portion of the anterior or great 
cardiac vein which is situated in the posterior part of the left auriculo-ventricular 
groove. It is about an inch in length, presents a considerable dilatation, and is 
covered by the muscular fibres of the left auricle. It receives most of the veins of 
the heart. Besides those mentioned it receives the oblique vein of Marshall (y. obliqua 
atrii sinistri) from the back part of the left auricle, the remnant of the obliterated 
left Cuvierian duct of the foetus, described by Mr. Marshall. The great coronary 
sinus terminates in the right auricle, between the inferior vena cava and the 
auriculo-ventricular aperture, its orifice being guarded by a semilunar fold of the 
lining membrane of the heart, the Thebesian valve. All the veins joining this 
vessel, excepting the oblique vein above mentioned, are provided with valves. 
The Venae Thebesii (yenoe cordis minimce) are numerous minute veins, which 
return the blood directly from the muscular substance, without entering the venous 
current. They open by minute orifices, foramina Thebesii (joramina venarum 
minamarum), chiefly on the inner surface of the right auricle. THE LYMPHATIC SYSTEM. 
Lymph is obtained from the blood-plasma. From lymph the body cells 
obtain food, into lymph they discharge their waste materials, and there is a 
distinct lymphatic circulation, the constituents of the plasma passing into the 
perivascular lymph-spaces and returning to the heart by way of the lymphatics 
and certain veins. 
The lymphatic system consists of lymphatic glands-large lymph-vessels, small 
lymph-vessels (lymphatic capillaries), the perivascular lymph-spaces, the lymph 
canalicular system, and the body cavities. To this system also belong the lacteal or 
chyliferous vessels. The lacteals are the lymphatic vessels of the small intestine, 
and differ in no respect from the lymphatics generally, excepting that during the 
process of digestion they contain a milk-white fluid, the chyle, which passes into 
the blood through the thoracic duct. 
The lymph canalicular system is the system of spaces in areolar connective 
tissue. The spaces are called lymph-spaces. In these spaces lie the cells of the 
tissue. The larger spaces are lined with endothelium, the smaller spaces are not 
lined with endothelium; they form connections with each other by anastomotic 
channels and constitute a system of spaces and channels which probably join 
the lymphatic capillaries. 
The perivascular lymph-spaces are found around certain blood-vessels. Each 
space is lined with endothelium, and is joined to other spaces by trabeculae of con- 
nective tissue. The spaces form a system which joins the lymphatic capillaries. 
Perivascular lymph-spaces have been demonstrated in the Haversian canals and 
in the subdural space of the pia mater. 
The pleural, pericardial, peritoneal, and synovial cavities belong to the lymphatic 
system. These cavities are lined by endothelial cells. Beneath the layer of lining 
cells are lymph-spaces or lymph-vessels, which communicate with the body cavity 
by means of numerous openings in the lining membrane. These openings are 
called stomata. 
Lymph-capillaries are larger than blood-capillaries, but the diameter of a lymph- 
capillary is different at different points, at some places being much larger than 
at others. Lymph-capillaries are formed of flattened endothelial cells. In some 
situations networks of lymphatic capillaries surround the blood-vessels. The 
lymph-vessels are called the lymphatics. 
The lymphatics have derived their name from the appearance of the fluid con- 
tained in their interior (lympha, water). They are also called absorbents, from the 
property they possess of absorbing certain materials from the tissues and con- 
veying them into the circulation. Larger lymphatics are called trunks and the 
largest are called ducts. 
The lymphatics are exceedingly delicate vessels, the coats of which are so 
transparent that the fluid they contain is readily seen through them, and they 
appear milky-white; hence the name Asellius gave them of lacteal veins. They 
retain a nearly uniform size, and may be cylindrical in shape, but usually are inter- 
rupted at intervals by constrictions which give them a knotted, beaded, or sac- 
like appearance. These constrictions are due to the presence of valves in the 
interior of the vessel. Lymphatic vessels do not invariably contain valves. Valves 
772 THE LYMPHATIC SYSTEM 
773 
are absent at the starting points of lymphatics, are absent in lymphatic capillaries, 
are not numerous in the largest ducts (thoracic duct), and are seldom found in vis- 
ceral lymphatics. The valves are not found in fixed situations and vary in number. 
Between the ends of the fingers and the axillary glands Sappey counted from sixty 
to eighty. "They are arranged in pairs and resemble the aortic semilunar valves.''1 
The lymphatic capillaries are composed purely of endothelium, but the collecting 
trunks possess not only an endothelial inner coat, but an investing elasto-muscular 
coat. Vessels in the subcutaneous connective tissue are devoid of muscle. Lymph- 
atics have been found in nearly every texture and organ of the body which contains 
blood-vessels. Such non-vascular structures as cartilage, the nails, cuticle, and 
hair have none, but with these exceptions it is probable that eventually all parts 
will be found to be permeated by these vessels. 
A larger lymphatic vessel is composed of three coats. The inner coat is 
composed of elastic tissue lined with endothelium. The middle coat is com- 
posed of elastic and muscular fibres. The external coat is composed of connec- 
tive tissue intermixed with smooth muscular fibres longitudinally or obliquely 
placed. 
'fhe thoracic duct possesses a subendothelial layer of connective tissue like that 
found in the arteries, and in the middle coat there is a longitudinal layer of 
connective tissue. The wall of a smaller lymphatic contains no elastic and no 
muscular tissue, and consists merely of connective tissue lined with endothelium. 
The lymphatics are arranged in superficial and deep sets. The superficial lym- 
phatics, on the surface of the body, are placed immediately beneath the integument, 
accompanying the superficial veins; they join the deep lymphatics in certain situa- 
tions by perforating the deep fascia. In the interior of the body the lymphatics 
lie in the submucous areolar tissue throughout the whole length of the gastro- 
puhnonary and genito-urinary tracts, and in the subserous tissue of the thoracic 
and abdominal cavities. In the cranial cavity the perivascular sheaths are lymph- 
spaces. A plexiform network of minute, closed, capillary lymphatics may be found 
interspersed among the proper elements and blood-vessels of the several tissues, the 
vessels composing which, as well as the meshes between them, are much larger than 
those of the capillary blood-vessel plexus. From these networks small collecting 
vessels emerge, pass to a neighboring gland, and divide into a capillary network 
in the gland. Numerous small vessels emerge from the gland, which unite into 
one lymphatic vessel, which joins a larger lymphatic trunk, which empties into 
a branch of the superior vena cava. The deep lymphatics, fewer in number and 
larger than the superficial, accompany the deep blood-vessels. Their mode of 
origin is probably similar to that of the superficial vessels. The lymphatics of 
any part or organ exceed the veins in number and in capacity, but in size they 
are much smaller. Their anastomoses also, especially those of the large trunks, 
are more frequent, and are effected by vessels equal in diameter to those which 
they connect. The continuous trunks retain the same diameter throughout. As 
the lymphatic vessels approach their point of discharge their number diminishes, 
but the calibre of the remainder does not increase in proportion. 
The gaps in the connective tissue, the larger of which are lined with endothelium, 
the smaller of which are devoid of endothelial lining, and all of which communicate 
with the lymphatic capillaries, are known as lymphatic spaces. It is asserted by 
some, but is not proved, that the spaces are continuous with the lymph-capillaries. 
Some hold that lymph gets from the spaces into the capillaries by means of open- 
ings in intervening tissue. The perivascular spaces, the serous cavities, and the 
ventricles of the brain resemble in function lymphatic structures. 
1 Treatise on Anatomy. By P. Poirier and A. Charpy. Article on the Lymphatics. By G. Delamare, P. Poirier, 
and B. Cun6o. 774 
THE LYMPHATIC SYSTEM 
The lymphatic or absorbent glands (lymphoglandulae), named also conglobate 
glands and lymph-nodes, are small, solid, glandular bodies situated in the course of 
the lymphatic and lacteal vessels. They vary from microscopic dimensions to the 
size of an olive, and their color, on section, is of a pinkish-gray tint, excepting the 
bronchial glands, which in the adult are mottled with black, the hepatic glands, 
which are yellow, and the splenic glands, which are brown. Each gland has 
a layer or capsule of cellular tissue investing it, from which prolongations dip 
into its substance, forming partitions. 'The lymphatic and lacteal vessels pass 
through these glands in their passage to the lymph- 
atic ducts. A lymphatic or lacteal vessel, previous to 
entering a gland, divides into several small branches, 
which are named afferent vessels (vasa afferentia). 
As they enter the gland, the external coat of each 
becomes continuous with the capsule of the gland, 
and the vessels becoming much thinned, and consist- 
ing only of their internal or endothelial coat, pass 
into the gland, and branch out upon and in the tissue 
of the capsule, these branches opening into the lymph- 
sinuses of the gland. There is an extensive sinus 
beneath the capsule; from this subcapsular sinus 
numerous branches run inward to a central sinus. 
From both sinuses fine branches proceed to form a 
plexus, the vessels of which unite to form a single 
efferent vessel (vas efferent), which, on emerging 
from the gland, is again invested with an external 
coat from the gland capsule. The lymph-glands are 
filters through which lymph and chyle flow. Car- 
cinoma cells are caught in them, and the dissemina- 
tion of the disease is retarded. In the glands are 
masses of newly formed leukocytes which attack any 
bacteria in the lymph or chyle. 
The size of the lymphatic glands decreases as age 
advances, and in very old individuals many glands 
actually disappear. It is impossible to estimate the 
number of macroscopic glands. Sappey estimated the number to be from 600 to 
700. Glands are embedded in fat and are distinctly movable. Some of them are 
superficial (above the deep fascia); others are deep (below the deep fascia). 
Occasionally a gland exists alone, but, as a rule, they are assembled in com- 
munities or chains of from eight to twelve, or even more. They are usually 
arranged around vessels, and often are upon vessels. The glands have a plen- 
tiful blood-supply, and contain not only vascular nerves, but definite nerve- 
plexuses. Besides the glands, the body contains numerous lymphoid areas, 
which, in structure and function, are allied to lymph-glands (tonsils, Peyer's 
patches, etc.). 
Fig. 481.-A lymph-node with its 
afferent and effeient vessels. (Tes- 
tut.) 
Surgical Anatomy.-In an operation for cancer it is not sufficient to cut wide of the growth 
and remove it; it is imperatively necessary to remove the lymphatic glands which receive lymph 
from the diseased area, and also, when possible, the lymphatic vessels between the cancer and 
the glands. Glands are diseased very early in cancer, long before they are palpably enlarged, 
and are usually infected by emboli of cancer cells. The rule is in any cancer, however recent, 
to regard the associated glands as diseased, whether enlarged or not, and to thoroughly remove 
them, if possible, in one piece, with the intervening lymph-vessels and the area of primary 
malignant growth. THE THORACIC AND RIGHT LYMPHATIC DUCT 
775 
THE THORACIC DUCT AND THE RIGHT LYMPHATIC DUCT. 
The thoracic duct or the left lymphatic duct (ductus thoracicus) (Figs. 482 and 
483) conveys the great mass of lymph and chyle into the blood. It is the common 
trunk of all the lymphatic vessels 
of the body below the Diaphragm, 
and usually, but not always, also 
receives the lymph from the left 
side of the body above the Dia- 
phragm. It does not drain the 
right side of the head and neck, 
the right upper extremity, the right 
lung, right side of the heart, and the 
convex surface of the liver. It partly 
drains the right chest wall. It varies 
in length from fifteen to eighteen 
inches in the adult, and extends from 
the second lumbar vertebra to the 
root of the neck. It commences in the 
abdomen by a triangular dilatation, 
the receptaculum chyli or the reser- 
voir or cistern of Pecquet (cisterna 
chyli), which is situated upon the 
front of the bodies of the first and 
of the second lumbar vertebra1, to 
the right side and behind the aorta, 
by the side of the right crus of the 
Diaphragm. The receptaculum is 
absent in some individuals. The 
thoracic duct ascends into the thorax 
through the aortic opening in the 
Diaphragm, lying to the right of 
the aorta, and is placed in the pos- 
terior mediastinum in front of the 
vertebral column, lying between 
the aorta and vena azygos major. 
Opposite the fourth dorsal vertebra 
it inclines toward the left side, and 
ascends behind the arch of the aorta 
on the left side of the oesophagus, 
and behind the first portion of the 
left subclavian artery, to the upper 
orifice of the thorax. Opposite the 
seventh cervical vertebra it turns 
outward and then curves downward 
over the subclavian artery and in 
front of the Scalenus anticus mus- 
cle, so as to form an arch, and ter- 
minates in the left subclavian vein 
at its angle of junction with the left 
internal jugular vein. It usually 
opens at the apex of the angle in the superior and outer surface, but may open 
on the posterior surface. Sometimes it terminates by two branches. Figs. 482 
Right 
lymphatic 
duct. 
Intercostal 
glands. 
Lumbar 
glands.' 
Fig. 482.-The thoracic and right lymphatic ducts. 776 
THE LYMPHATIC SYSTEM 
and 485 show the termination of the thoracic duct. The thoracic duct, at 
its commencement, is about equal in diameter to that of a goose-quill, dimin- 
ishes considerably in its calibre in the middle of the thorax, and is again 
dilated just before its termination, the ampulla. It is generally flexuous in its 
COMMON LYMPHATIC 
TRUNK FROM HEAD 
AND UPPER LIMB 
THYROID 
AXIS 
VERTEBRAL 
ARTERY 
INTERNAL JUGULAR 
VEIN 
COMMON CAROTID 
ARTERY 
(ESOPHAGUS 
THYROID 
BODY 
TRACHEA 
COMMON CAROTID 
ARTERY 
VERTEBRAL 
ARTERY 
INTERNAL JUGULAR 
VEIN 
THYROID 
AXIS 
PHRENIC 
NERVE 
SCALENUS ANTICUS 
MUSCLE 
CLAVICLE 
SUBCLAVIAN 
ARTERY 
SUBCLAVIAN 
VEIN 
SCALENUS ANTICUS 
MUSCLE 
SUPERIOR INTER- 
COSTAL VEIN 
SUBCLAVIAN 
ARTERY 
MEDIASTINAL LYM- 
PHATIC VESSEL* 
SUPERIOR 
INTERCOSTAL 
jvEIN 
BRONCHIAL 
LYM PHATIC 
VESSEL 
VENA AZYGOS 
MINOR 
SUPERIOR 
VENA AZYGOS. 
MAJOR 
VENA AZYGOS 
MINOR INFERIOR 
DESCENDING 
THORACIC LYM- 
PHATIC TRUNK 
CESOPHAGUS 
DESCENDING THORACIC 
LYM PHATIC TRUNK 
THORACIC 
DUCT 
IN FERIOR 
PHRENIC ARTERY 
RECEPTACULUM 
CHYLI 
SUPRARENAL 
BODY 
SUPRARENAL 
BODY 
CCELIAC AXIS 
SUPERIOR 
M ESENTERIC 
RIGHT RENAL, 
ARTERY 
COMMON INTESTINAL 
LYM PHATIC TRUNK 
LEFT RENAL. 
vein" 
RENAL ARTERY 
LUMBAR. 
VEINS 
COMMON LUMBAR 
lymphatic trunk 
Fig. 483.-Thoracic duct and its tributaries. (Cunningham.) 
course, the older the person the greater the flexuosity, and it is constricted at inter- 
vals so as to present a varicose appearance. The thoracic duct not infrequently 
divides in the middle of its course into two branches of unequal size, which 
soon reunite, or divides into several branches, which form a plexiform interlace- 
ment. It occasionally divides, at its upper part, into two branches, of which the THE THORACIC AND RIGHT LYMPHATIC DUCT 
777 
one on the left side terminates in the usual manner, while that on the right opens 
into the right subclavian vein, in connection with the right lymphatic duct. The 
thoracic duct has several valves throughout its whole course, but they are more 
numerous in the upper than in the lower part, and the lower valves are not com- 
petent; at its termination it is provided with a pair of competent valves, the free 
borders of which are turned toward the vein, so as to prevent the passage of 
venous blood into the duct. 
The common intestinal trunk (truncus intestinalis) (Figs. 483, 484, and 511) 
empties into the receptaculum and brings lymph from the small intestine (lacteals), 
the stomach, the pancreas, and the spleen. 
Radicals of Origin and Tributaries.-In most individuals the juxta-aortic 
glands which are placed on each side of the aorta send a vessel upward and 
inward, which unite to form the thoracic duct. The right vessel is known as 
the truncus lymphaticus lumbalis dextra. The left vessel is known as the truncus 
lymphaticus lumbalis sinistra. A vessel from the glands in front of (pre-aortic) 
and back {retro-aortic) of the aorta empties into each of the above-named vessels. 
In some cases a large vessel forms from the glands in front of the aorta and helps 
form the duct. The receptaculum chyli receives the common intestinal lymphatic 
trunk, which conveys lymph from the small intestine, stomach, spleen, pancreas, 
and a portion of the liver. 
Fig. 484.-Modes of origin of the thoracic duct. a, thoracic duct; a', receptaculum chyli; b, common 
trunk of the efferents of the right juxta-aortic glands; c, common trunk of the efferents of the left juxta- 
aortic glands; d, one of these efferents passing through the left pillar of the diaphragm; e, right juxta-aortic 
gland; /. left juxta-aortic gland; h, retro-aortic gland; i, common trunk of the pre-aortic glands (truncus 
intestinalis); j, collecting trunks of the intercostal lymphatics, which reach the receptaculum chyli by taking 
the downward course. (Poirier and Charpy.) 
The branches of the left lymphatic duct are (Fig. 483): 1. A descending trunk, 
which collects lymph from the posterior intercostal glands of the seven lower 
intercostal spaces. 2. A trunk is formed by vessels coming from the superior juxta- 
aortic glands beneath the Diaphragm. 3. The lymphatic vessels form the upper 
five intercostal spaces. 4. The lymphatic vessels form the posterior mediastinal 
glands and retrosternal glands. 5. The left jugular trunk (truncus jugularis), 
although this may open directly into the junction of the subclavian and internal 
jugular veins. 6. In rare cases the thoracic duct receives near its termination 
the left subclavian trunk (truncus subclavius) and a broncho-mediastinal trunk. 
As a rule, however, the two last-mentioned trunks empty into the jugulo-subclavian 
junction separately or as one duct. 
The thoracic duct receives the lymph from the extremities, the deep portion 
of the abdominal wall and of the pelvic wall, the pelvic viscera, the kidneys and 
suprarenal capsules, the la'ge intestine, the small intestine, the walls of the 
thoracic cavity, the under surface and anterior portion of the liver, the stomach, 778 
THE LYMPHATIC SYSTEM 
the spleen, the pancreas, the sternal and intercostal glands, the left lung, left 
side of the heart, trachea, and oesophagus, and often, just before its termination, 
the lymphatics of the left side of the head and neck, and of the left upper 
extremity. 
Structure.-The thoracic duct is composed of three coats, which differ in some 
respects from those of the lymphatic vessels. The internal coat consists of a single 
layer of flattened endothelial cells; of a subendothelial layer, similar to that found 
in the arteries; and an elastic fibrous coat, the fibres of which run in a longitudinal 
direction. Each endothelial cell is shaped like a lance-head and has serrated 
LONGUS COLLI MUSCLE 
COMMON CAROTI D 
ARTERY 
LEFT PNEUMOGASTRIC 
NERVE 
VERTEBRAL ARTERY 
VERTEBRAL VEIN 
THORACIC DUCT 
INTERNAL JUGULAR 
VEIN 
EXTERNAL JUGULAR 
VEIN 
ANTERIOR JUGULAR 
VEIN 
SUBCLAVIAN 
VEIN 
Fig. 485.-The bend of the thoracic duct at its termination in the subclavian vein. (Poirier and Charpy.) 
borders. The middle coat consists of a longitudinal layer of white connective 
tissue with elastic fibres, external to which are several lamime of muscular 
tissue, the fibres of which are for the most part disposed transversely, but some 
are oblique or longitudinal. The muscular fibres are intermixed with elastic 
fibres. The external coat is composed of areolar tissue, with elastic fibres and 
isolated fasciculi of muscular fibres. 
The Right Lymphatic Duct (Ductus Lymphaticus Dexter) 
(Figs. 482, 486, 487, 511). 
A right lymphatic duct is frequently present. Tt is a short trunk, about half an 
inph in length and a line or a line and a half in diameter. It is formed by the union 
Fig. 486.-Terminal collecting trunks of the right half of the supra-diaphragmatic portion of the body. a. 
jugular trunk; b, subclavian trunk; c, broncho-mediastinal trunk; d, right lymphatic trunk; e, gland of the 
internal mammary chain; f, gland of the deep cervical chain. (Poirier and Charpy.) 
of the right jugular, right broncho-mediastinal, and right subclavian trunks. 
Often on the right side the jugular, subclavian, and broncho-mediastinal trunks LYMPHATICS OF THE CRANIAL REGION, FACE AND NECK 
779 
are double. Usually they open into the junction of the internal jugular and 
subclavian veins separately. Sometimes they unite and open by one duct, and 
that is the right lymphatic duct. The orifice of the right lymphatic duct is 
guarded by two semilunar valves, which prevent the passage of venous blood 
into the duct. 
Tributaries.-The right lymphatic duct, if present, receives lymph from the 
right side of the head and neck, the right upper extremity, the right side of 
the thorax, the right lung, and the right side of the heart, and from part of the 
convex surface of the liver. 
LYMPHATICS OF THE CRANIAL REGION, FACE, AND NECK. 
It is customary to divide the lymphatics of this region into intracranial and 
extracranial lymphatics. The statement is made by Poirier and Cuneo1 that the 
RIGHT 
-LYM PHATIC 
DUCT 
Fig. 487.--The lymphatics of the head and neck. (Sappey.) 
brain and its membranes are without lymphatics. They state that there are 
spaces in the nervous centres comparable to lymphatic channels, but which are 
not truly lymphatic vessels and which are regarded by most as independent of the 
lymphatic system. Other writers2 believe that there are cerebral and meningeal 
lymphatic vessels. It is highly probable that the perivascular spaces around the 
cerebral arteries are the beginning of a cerebral lymph system, and that these peri- 
' Article on the Lymphatics in the Treatise on Human Anatomy. By Poirier and Charpy. 
2 Cunningham's Text-book of Anatomy. 780 
THE LYMPHATIC SYSTEM 
vascular lymph-channels pass out of the cranium with the arteries and the internal 
jugular vein and terminate in the superior deep cervical glands. It is also probable 
that lymph-spaces surround the meningeal blood-vessels and terminate in the 
superior deep cervical and the internal maxillary glands. 
The extracranial lymphatics are divided into superficial and deep, and the two 
systems freely communicate. All of these vessels run into glands about the 
head and neck. The superficial lymphatics take origin in the subcutaneous 
tissue and superficial muscles. The deep vessels arise in the orbit, mouth, nose, 
pharynx, oesophagus, tongue, larynx, and the muscular, ligamentous, and osseous 
structures. 
The Lymphatic Glands of the Head and Face. 
The lymphatic glands of the head and face are as follows: 
1. The Occipital. 
2. The Posterior Auricular. 
3. The Parotid and Subparotid. 
4. The Internal Maxillary. 
5. The Facial. 
The Occipital or Suboccipital Glands (lijmphoglandulae occipitales) (Figs. 
488 and 493).-There are only two or three of these glands on each side. They 
are situated beneath the deep fascia, a little in front of the anterior edge of the 
MASTOID 
OCCIPITAL 
PAROTID 
FACIAL 
SUBMAXILLARY 
DEEP 
CERVICAL 
CHAIN 
SUBMENTAL 
Fig. 488. General arrangement of the lymphatic gland groups of the head and neck. (Poirier and Charpy.) 
1 rapezius muscle, near to but seldom upon the insertion of the Complexus 
muscle. 1 hey receive lymph from the occipital region of the scalp and from 
them it is sent to the upper deep cervical glands. 
The Posterior Auricular Retro-auricular or Mastoid Glands (lymphoglandulae 
aiiriculares posteriores} (Figs. 488,492, and 493).-There are two of these on each 
side. They are situated just beneath the lower margin of the Retrahens aurem 
muscle. They receive lymph from the parietal lymph-vessels, "from the internal THE LYMPHATIC GLANDS OF THE HEAD AND FACE 
781 
surface of the auricle, with the exception of the lobule, and from the posterior 
surface of the external auditory meatus."1 The lymph-vessels from these glands 
empty into the upper deep cervical glands. 
PAROTID- 
FACIAL 
SUBMAXILLARY 
GLANDS OF 
EXTERNAL JUGULAR 
CHAIN 
GLAND OF 
INTERNAL JUGULAR 
CHAIN 
Fig. 489.-The lymphatics of the neck. (Kiittner.) 
The Parotid Lymph-glands (lymphoglandulae auriculares anteriores) (Figs. 
488, 489, and 493) are divided into two groups, the superficial and the deep. 
The Superficial Parotid or Pre-auricular Lymph-glands.-The superficial parotid 
lymph-glands are not the subcutaneous lymph-glands occasionally but very rarely 
SUBORBITAL 
GLAND OF NASO- 
GENIAL GROOVE 
BUCCINATOR 
(posterior mass) 
BUCCINATOR 
(middle mass) 
SUPRAM AXILLARY 
- I N FR AM AXI LLA RY 
Fig. 490.-Facial glands. (Poirier and Charpy.) 
found in this region, and which have been described by Richet, but are lymph- 
nodes situated between the parotid fascia and the parotid salivary gland. There 
may be three glands, two glands, or only one gland. 
1 The Lymphatics. By G. Delamare, P. Poirier, and B. Cun£o. English edition, translated and edited by 
Cecil H. Leaf. 782 
THE LYMPHATIC SYSTEM 
The Deep Parotid Lymph-glands.-The deep parotid lymph-glands are situated 
within the parotid salivary gland. There are from fifteen to twenty of the deep glands. 
The parotid glands receive lymph from the eyelids, eyebrows, the root of the nose, 
upper portion of the cheek, frontal portion of the scalp, temporal portion of the 
scalp, from the outer surface of the pinna, from the external auditory meatus, 
from the tympanum, and possibly from the mucous membrane of the nose, the 
posterior alveolar region of the superior maxillary bone, and the soft palate. 
Lymphatics pass from the superficial parotid glands into the superficial cervical 
and the upper deep cervical glands. Lymphatics pass from the deep parotid 
glands into the upper deep cervical glands. 
The Subparotid Glands (lymphoglandulae parotidae) .-The subparotid glands 
lie between the parotid salivary gland and the pharynx, and they are close to the 
internal carotid artery and the internal jugular vein. They receive lymph from 
the nasal fossae, naso-pharynx, and Eustachian tube, and send vessels to the upper 
deep cervical glands. 
The Internal Maxillary or Zygomatic Glands (lymphoglandulae jaciales pro- 
jundae) (Fig. 493).-The internal maxillary glands lie in the course of the internal 
maxillary artery in the anterior pharyngeal wall. They receive vessels from the 
naso-pharynx, palate, zygomatic fossa, temporal fossa, and orbit. From them 
vessels go to the upper deep cervical glands. 
The Facial Glands or Genial Glands (lymphoglandidae jaciales) (Figs. 488, 
489, and 490).-The facial glands lie in three groups in the course of the lymphatic 
vessels which are passing to the submaxillary glands. According to Poirier and 
Cun£o the supramaxillary or inferior group (Fig. 490) lies upon the outer surface 
of the mandible, at the anterior margin of the Masseter muscle, and beneath the 
Platysma myoides. There may be only one or two glands in this group, but often 
there are ten or twelve. These glands lie about the facial artery and vein and 
are not constantly present. In many cases a salivary gland, the inframaxillary 
(Fig. 490), is interposed between the supramaxillary and submaxillary glands. 
The buccinator, buccal, or middle group (Figs. 490 and 493) is present in about 
one-third of the subjects and lies upon the outer surface of the Buccinator muscle 
external to the buccal fascia. Some of these glands are situated in the region 
where Steno's duct perforates the Buccinator muscle. Others are beneath the 
posterior fibres of the Zygoinaticus major muscle. 
The superior group of facial glands (Fig. 490) includes a malar gland, a suborbital 
gland, and a gland in the naso-genial groove.1 An anterior gland is sometimes 
found, subcutaneous, on the outer surface of the Orbicularis oris muscle, the 
commissural gland. 
The Lymphatic Vessels of the Cranial Region (Figs. 487, 493). 
The lymphatic vessels of the cranial subcutaneous tissues are divided into 
anterior, lateral, and posterior. The anterior or frontal terminate in the parotid 
lymph-glands. The lateral or parietal terminate in the parotid and mastoid lymph- 
glands. The posterior or occipital terminate in the sterno-mastoid and occipital 
glands. 
The Lymphatic Vessels of the Face, the Interior of the Nose, Tongue, Floor 
of the Mouth, Pharynx, Larynx, and Thyroid Gland 
(Figs. 487, 489, 490, 491, 492, 494). 
The lymphatic vessels of the face are more numerous than those of the cranial 
region, and commence over its entire surface. Those from the frontal region 
accompany the frontal vessels; they then pass obliquely across the face, running 
1 Article on the Lymphatics in the Treatise on Human Anatomy. By P. Poirier and B. CunCo. THE LYMPHATIC VESSELS OF THE FACE 
783 
with the facial vein, pass through the glands on the buccal surface of the Buccina- 
tor muscle, and join the submaxillary lymphatic glands. The submaxillary lymph 
glands receive the lymphatic vessels from the lips, and are often found enlarged 
in cases of malignant disease of those parts. 
The lymphatics of the orbit and of the temporal and zygomatic fossae run with 
the branches of the internal maxillary artery to the maxillary glands, and after- 
ward to the deep cervical glands. 
VESSELS FROM 
BASE OF TONGUE 
MARGINAL COL- 
LECTING TRUNKS 
TRUNKS OF 
MARGIN 
TRUNKS 
OF APEX 
PRINCIPAL. 
GLAND 
SUBMENTAL 
TRUNKS OF 
MARGIN 
INTERRUPTING 
NODULE 
CENTRAL 
'TRUNK 
SUPRA-OMO- 
HYOID gland' 
Fig. 491.-The lymphatics of the tongue; anterior view. (Poirier and Charpy.) 
The lymphatics of the nose can be injected from the subdural and subarachnoid 
spaces. They terminate in the retro-pharyngeal and suprahyoid glands. The 
lymphatics of the tongue (Fig. 491) chiefly accompany the ranine vein first to the 
lingual glands and from these to the deep cervical glands. The lymphatics from 
the anterior part of the tongue and floor of the mouth pierce the Mylo-hyoid muscles 
and so reach the submaxillary lymph-glands (p. 1093). From the upper part of 
the pharynx the lymphatics pass to the retro-pharyngeal glands; from the lower 
part of the pharynx to the deep cervical glands. From the larynx two sets of vessels 
arise: an upper, piercing the thyro-hyoid membrane and joining the upper set 
of deep cervical glands; and a lower, perforating the crico-thyroid membrane to 
join the lower set of deep cervical glands. The lymphatics of the thyroid gland 
accompany the superior and inferior thyroid arteries, and open partly into the 
upper and partly into the lower set of deep cervical glands. 784 
THE LYMPHATIC SYSTEM 
The Lymphatic Glands of the Neck. 
The lymphatic glands of the neck are: 
1. The Superficial Cervical, including the external jugular and the superficial 
anterior cervical. 
2. The Submaxillary. 
3. The Submental. 
4. The Retro-pharyngeal. 
5. The Deep Cervical, including the anterior deep cervical. 
The Superficial Cervical Glands (Jymphoglandulae cervicales superfidales) 
(Figs. 492 and 493).-The superficial cervical glands are composed of two groups, 
the external jugular and the superficial anterior cervical glands. 
The External Jugular Glands (Figs. 489 and 492).-The external jugular glands 
are superficial to the Sterno-cleido-mastoid muscle. They are four to six in 
LYMPHATIC VESSELS 
OF AURICLE 
MASTOID GLANDS 
STERNO-MASTOID 
gland (external 
group) 
GLAND OF 
EXTERNAL JUGULAR 
CHAIN 
STERNO-MASTOI D 
gland (internal 
group) 
SUBHYOID GLAND 
Fig. 492.-Deep cervical chain. (Poirier and Charpy.) 
number and lie along the external jugular vein upon the outer surface of the deep 
cervical fascia, each gland occupying a depression in the fascia. The sterno- 
cleido-mastoid muscle is beneath them. They are usually gathered in a group 
a little below the parotid gland, but sometimes extend to the middle of the vein. 
They receive vessels from the occipital, the posterior auricular, the parotid, and 
the submaxillary lymph-glands, from the auricle, and from the skin and subcu- 
taneous structures of the neck. From them lymphatic vessels pass to the upper 
deep cervical and to the lower deep cervical glands. 
The Superficial Anterior Cervical Glands.-The superficial anterior cervical glands 
lie along the anterior jugular vein and from them vessels pass to the deep cervical 
glands. 
The Submaxillary or Lateral Suprahyoid Glands (lymphoglandulae submaxil- 
lares) (Figs. 488, 489, and 493).-The submaxillary glands are in the submaxil- 
lary triangle beneath the deep fascia. They number three to six; are embedded 
in the superficial surface of the sheath of the submaxillary gland, but are not found 
within the sheath. Occasionally one or two are found in the deep portion of the 
sheath toward the floor of the mouth. The middle gland of Stahr is situated at 
the point where the submaxillary group is crossed by the facial artery. This is 
the largest gland of the group. The submaxillary glands receive vessels from the THE LYMPHATIC GLANDS OF THE NECK 
785 
"nose, the cheek, the upper lip, and the external part of the lower lip, almost 
the whole of the gums, and the anterior third of the lateral border of the tongue."1 
They also obtain lymph from the floor of the mouth and from the sublingual and 
submaxillary salivary glands.2 They send vessels to the jugular and to the upper 
deep cervical glands. 
The Submental or Median Suprahyoid Glands (Figs. 488, 491, and 493).- 
There are usually two glands situated between the anterior bellies of the two 
digastric muscles and upon the Mylo-hyoid muscle. They receive lymph from the 
cutaneous surface of the chin, from the cutaneous and mucous surfaces of the 
OCCIPITAL- 
MASTOID. 
-ZYGOMATIC 
SUPERFICIAL 
PAROTID 
SUPERFICIAL 
CERVICAL 
'BUCCAL 
SUBMENTAL 
SUBMAXILLARY 
'DEEP CERVICAL 
INFRALARYNGEAL 
■TRACHEAL 
Fig. 493.-The lymphatic glands and vessels of the head and neck. The deep lymphatics are colored blue 
and the superficial black. In each set the afferent vessels are shown in continuous lines; the efferent and inter- 
glandular vessels are represented by dotted lines. (Cunningham.) 
central portion of the lower lip, from the central portion of the gums, from the 
floor of the mouth, and from the tip of the tongue. They send some vessels to 
the submaxillary lymph-glands, and frequently a gland is interposed on the anterior 
belly of the Digastric muscle. They send other vessels to the upper deep cervical 
glands. 
The Retro-pharyngeal or Post-pharyngeal Glands (Fig. 494).-The retro- 
pharyngeal glands are placed between the upper lateral portion of the posterior 
part of the pharynx and the first two cervical vertebrae. Leaf tells us that, as a 
1 The Lymphatics. By G. Delamare, P. Poirier, and B. Cun6o. Translated and edited by Cecil H. Leaf. 
2 Cunningham's Text-book of Anatomy. THE LYMPHATIC SYSTEM 
786 
rule, there is but one gland on each side, though two may be present. The retro- 
pharyngeal glands lie upon the Rectus capitis anticus major muscle, which sepa- 
rates them from the vertebrae. They receive vessels from the muscles and fascia 
in front of the vertebrae, from the nasal fossae and accessory cavities, from the naso- 
pharynx and Eustachian tube, and possibly from the cavity of the tympanum. 
They send vessels to the upper deep cervical glands. 
The Deep Cervical, Carotid, or Sterno-mastoid Glands (lymphoglandulae 
cervicales projundae) (Figs. 488, 489, 491, 492, 493, and 494).-The deep cervical 
glands are divided into the upper deep cervical and the lower deep cervical, and are 
associated with certain accessory glands, including the jugular and superficial anterior 
cervical, which have been discussed under the head of superficial cervical glands; 
and the anterior deep cervical and the recurrent glands, which have not yet been 
studied. The deep cervical chain extends from the apex of the mastoid process 
of the temporal bone to the junction of the internal jugular and subclavian veins. 
RETRO-PHARYNGEAL 
GLAN DS 
AFFERENT 
VESSEL OF RETRO- 
PHARYNGEAL 
GLANDS 
LYMPHATICS 
OF PHARYNX 
INTERRUPTING 
GLANDULAR 
NODULE 
GLAND OF 
.DEEP CERVICAL 
CHAIN 
.EFFERENT 
VESSEL OF 
RETRO-PHARYNGEAL 
GLANDS 
Fig. 494.-The retro-pharyngeal glands. (Poirier and Charpy.) 
The Upper Deep Cervical or Substerno-mastoid Glands (lymphoglandulae cervi- 
cales projundae superiores).-The upper deep cervical glands extend from the 
tip of the mastoid process of the temporal bone to about the region where the 
common carotid artery is crossed by the Omo-hyoid muscle. One group, 
the external group, is placed external and posterior to the internal jugular vein. 
The glands are small and numerous, are embedded in the fatty tissue about the 
nerves from the deep cervical plexus, and at the posterior margin of the Sterno- 
cleido-mastoid muscle constitute a continuous mass passing to join the subclavian 
glands. Another group, known as the internal group or the internal jugular 
glands, lie directly upon or close by the outer border of the internal jugular vein. 
This group forms a chain along the internal jugular vein, and the glands are 
of larger size than those of the external group. Some glands of this group 
are beneath the vein. The glands of the internal jugular group communicate 
freely with each other and with the external group. The external group receives 
lymph-vessels from the posterior auricular, occipital, and external jugular glands, 
from the occipital region of the scalp, from the auricle, and from the skin, sub- 
cutaneous tissue, and muscles of the upper portion of the neck.1 The internal 
group receives lymph-vessels from the retro-pharyngeal, parotid, subparotid, sub- 
1 The Lymphatics. By G. Delamare, P. Poirier, and B. Cun^o. Translated and edited by Cecil H. Leaf. THE LYMPHATIC VESSELS OF THE NECK 
787 
maxillary, and submental glands, the anterior cervical glands (superficial and 
deep), and the recurrent glands, and from the tongue, naso-pharynx, larynx, soft 
palate, roof of the mouth, oesophagus (cervical portion), nasal fosste, trachea 
(cervical portion), and the thyroid gland.1 The external group terminates in 
the supraclavicular glands. The internal jugular group terminates in the 
jugular trunk, which, on the right side, helps to form the right lymphatic duct 
or empties directly into the junction of the internal jugular and subclavian veins, 
and on the left side empties directly into the venous junction or into the thoracic 
duct. 
The Lower Deep Cervical or Supraclavicular Glands (lymphoglandulae cervicales 
profundae inferiores).-The lower deep cervical glands lie along the internal 
jugular vein in the lower part of its course. They receive lymph-vessels 
from the superficial cervical glands, the upper deep cervical glands, the 
axillary glands, the accessory chain, the occipital region of the scalp, the skin of 
the neck, the lower prevertebral muscles, the skin of the pectoral and mammary 
regions, and the skin of the arm. The supraclavicular glands send vessels which 
unite with the vessels of the upper deep glands to form the jugular lymphatic 
trunk. The jugular trunk on the right side may empty directly into the junc- 
tion of the internal jugular and subclavian veins or may unite with the subclavian 
trunk to form the right lymphatic duct. On the left side it may empty into the 
thoracic duct or directly into the venous junction. 
Accessory Chains to the Deep Cervical Glands.-The accessory chains to the deep 
cervical glands are: 1. The external jugular glands (p. 784). 2. The superficial 
anterior cervical (p. 784). 3. The prelaryngeal or infralaryngeal glands (Fig. 493) 
between the Crico-thyroid muscles. They receive lymph from the trachea, larynx, 
and thyroid gland, and send vessels to the pretracheal glands and to the upper 
deep cervical glands. 4. The tracheal or pretracheal glands (Fig. 493) lie upon the 
front of the trachea, receive vessels from the trachea, thyroid body, and prelaryngeal 
glands, and send vessels to the lower deep cervical glands. Some anatomists speak 
of the prelaryngeal and the pretracheal glands as the anterior deep cervical glands. 
5. The recurrent glands lie on the sides of the oesophagus and trachea, by the recur- 
rent laryngeal nerves. They receive vessels from the larynx, trachea, oesophagus, 
and thyroid gland, and send vessels to the upper and lower deep cervical glands. 
The Lymphatic Vessels of the Neck (Figs. 487, 491, 492, 493). 
The superficial and deep cervical lymphatic vessels are continuations of those 
already described on the cranium and face. After traversing the glands in those 
regions, they pass through the chain of glands which lie along the sheath of the 
carotid vessels, being joined by the lymphatics from the pharynx, (esophagus, 
larynx, trachea, and thyroid gland. At the lower part of the neck, after receiving 
some lymphatics from the thorax, they unite to form the jugular trunk (Fig. 486), 
which often terminates, on the left side, in the thoracic duct, and on the right side, 
in the right lymphatic duct, but which may on either side open directly into the vein. 
Surgical Anatomy.-In secondary syphilis there is general enlargement of the lymphatic 
glands, and in the posterior triangle of the neck the enlarged glands are distinctly palpable. The 
occipital glands may enlarge because of inflammation or suppuration about the occipital region 
of the scalp, and the posterior-auricular glands enlarge from inflammation or suppuration of the 
temporal portion of the scalp, the external ear (except the lobule), and the external auditory meatus. 
Otorrhoea sometimes causes them to enlarge. 
The cervical glands are very frequently the seat of tuberculous disease. This condition is 
usually preceded by a lesion in those parts from which they receive their lymph. The lesion may 
be tuberculous or inflammatory. If tuberculous it furnishes bacilli directly to the lymph. If 
inflammatory it lessens tissue resistance and opens the portals to infection. The glands receive 
1 The Lymphatics. By G. Delamare, P. Poirier, and B. Cun6o. Translated and edited by Cecil H. Leaf. 788 
THE LYMPHATIC SYSTEM 
the lymph from the seat of primary disease and become tuberculous. It is very desirable, there- 
fore, for the surgeon, in dealing with these cases, to possess a knowledge of the relation of the 
respective'groups of glands to the periphery. Some years ago Sir Frederick Treves prepared a 
table to show to what glandular group lymph from each region is sent. The table is practically 
as follows: 
Scalp.-Posterior part = suboccipital and mastoid glands. Frontal and parietal portions = 
parotid glands. 
Lymphatic vessels from the scalp also enter the superficial cervical set of glands. 
Skin of face and neck - submaxillary, parotid, and superficial cervical glands. 
External ear = superficial cervical glands. 
Lower lip = submaxillary and suprahyoid glands. 
Buccal cavity = submaxillary and upper set of deep cervical glands. 
Gums of lower jaw = submaxillary glands. 
Tongue.-Anterior portion = suprahyoid and submaxillary glands. Posterior portion = 
upper set of deep cervical glands. 
Tonsils and palate = upper set of deep cervical glands. 
Pharynx.-Upper part = parotid and retro-pharyngeal glands. Lower part = upper set of 
deep cervical glands. 
Larynx, orbit, and roof of mouth = upper set of deep cervical glands. 
Nasal fossw = retropharyngeal glands, upper set of deep cervical glands. Some lymphatic 
vessels from posterior part of the fossae enter the parotid glands. 
Treves's table indicates the glands usually involved, but the seat of primary disease cannot in- 
variably be affirmed from a knowledge of the seat of glandular involvement, because the course 
of the lymphatic vessels is sometimes varied from that which usually maintains; for instance, in 
some cases lymphatics from the right side of the tongue pass to glands in the left side of the 
neck. 
Glands may enlarge directly because of primary inflammation, injury, or tumor, but usually 
a glandular enlargement is secondary to a bacterial disease or to cancer involving the lymph- 
vessels which come to the gland. The seat of disease may be distant. Disease of the nasal 
fossae may cause retropharyngeal abscess or enlargement of the submaxillary glands. Cancer 
of the breast, stomach, or oesophagus may be followed by disease of the cervical glands. Dis- 
ease of the teeth, tongue, gums, floor of the mouth, and alveolar processes may cause enlarge- 
ment of the submaxillary and other glands, and disease of the tonsil may lead to enlargement 
of the glands at the angle of the jaw. 
The modern radical surgery of cancer depends on a knowledge of these glandular relations, 
and consists in thoroughly removing the growth and also the associated lymphatic glands, and, 
when possible, the lymph-vessels running from the tumor to the glands. The lower deep cer- 
vical glands occasionally enlarge secondarily to malignant growths of the abdomen or medias- 
tinum, but this is not due to a direct flow of lymph, as the mediastinal glands do not send ves- 
sels to the supraclavicular glands. It is due to blocking of lymphatic vessels and reversal of 
the lymph-stream, so that lymph containing cancerous cells regurgitates. 
A retropharyngeal abscess begins to the side of the pharynx. It enlarges toward the centre 
rather than from it, because the constrictions of the pharynx limit the outward progress of the 
pus. 
The glands within the parotid salivary gland not unusually become tuberculous, and the 
surgeon may be led to believe that the salivary gland is the seat of primary disease. 
Sometimes, though seldom, after the extensive removal of lymph-glands the region drained 
by their tributaries becomes the seat of persistent hard cedema {lymph oedema}. It used to be 
thought that wounds of the thoracic duct were of necessity fatal, but it is now known that, unless 
close to the vein, they are seldom even very dangerous. It may be possible to suture a partly 
divided duct.1 In an unsutured wound of the duct recovery follows if a collateral lymphatic 
circulation is established.2 
THE LYMPHATICS OF THE UPPER EXTREMITY. 
The Lymphatic Glands of the Upper Extremity. 
The lymphatic glands of the upper extremity are divided into two sets, super- 
ficial and deep. 
Superficial Lymphatic Glands (Figs. 495 and 503).-The superficial lymphatic 
glands of the upper extremity are few in number and small in size. They lie in the 
1 Dudley P. Allen's case. See Allen and Briggs, in American Medicine, September 21, 1901, 
2 Harvey Cushing, Annals of Surgery, June, 1898. THE LYMPHATIC GLANDS OF THE UPPER EXTREMITY 
789 
subcutaneous tissue. They are not receiving depots of great areas, but interrupt 
lymphatic vessels here and there. The glands in the axilla receive all of the 
lymphatic vessels, superficial and deep. There may be three sets of superficial 
glands. 
One set, the ante-cubital glands, lies in front of the elbow. These glands are 
often absent. When these glands are present they receive vessels from the anterior 
portion of the forearm and the middle of the palm. The vessels from them pass 
upward along the front and inner aspect of the arm. 
Axillary glands.^ 
Fig. 495.-The superficial lymphatics and glands of the upper extremity. 
Another superficial gland lies above the internal condyle. It is the supratrochlear 
or supraepitrochlear gland or group of glands. There is usually but one gland, but 
there may be two or more. It receives vessels from the inner portion of the hand, 
the three inner fingers, and the inner portion of the forearm, but, because of free 
anastomoses, also may receive lymph from any portion of the hand and forearm. 
Lymph-vessels from the supratrochlear gland pass up along the basilic vein to 
the axillary glands. THE LYMPHATIC SYSTEM 
790 
There are sometimes several small glands by the cephalic vein in the groove 
between the Deltoid and great Pectoral muscles. These are called infraclavicular 
glands. The lymph-tract from the infraclavicular glands does not terminate in 
the axillary glands, but ends in the subclavian glands. 
The Deep Lymphatic Glands of the Upper Extremity or the Axillary Glands 
(lymphoglandulae axillares) (Figs. 495, 496, 497, 498, and 503).-The chief deep 
glands are situated adjacent to the axillary vessels. There are also a few small 
glands along the radial, ulnar, and brachial arteries which receive deep lymphatics 
from bones, muscles, and ligaments, and send lymphatics to the axillary glands. 
The axillary glands number from fifteen to thirty-five in each axilla. They are 
embedded in the axillary fat and receive the lymphatic vessels from the upper 
extremity, from the skin of the upper portion of the chest, from the Pectoral 
muscles, and from the mammary gland. The following division of the axillary 
glands is made by Poirier, Cuneo, and Delamare:1 1. An external group, the 
DELTA-PECTORAL 
HUMERAL CHAIN 
HUMERAL 
^CHAIN 
SUBCLAVIAN 
CENTRAL' 
GROUP 
-MAMMARY LYMPHATIC 
ENDING I N SUB- 
CLAVIAN GLANDS 
SCAPULAR 
CHAIN 
THORACIC 
'CHAIN 
THORACIC^ 
CHAIN" 
MAMMARY COL- 
LECTING TRUNKS 
THORACIC. 
CHAIN 
.SUBAREOLAR 
'plexus 
CUTANEOUS COLLECTING 
TRUNK FROM THE 
THORACIC WALL 
CUTANEOUS COL- 
LECTING TRUNKS 
COLLECTING TRUNKS 
PASSING TO INTERNAL 
MAMMARY GLANDS 
Fig. 496.-Axillary glands and lymphatics of the breast. 
humeral chain, lying on the inner surface of the vessels and nerves, particularly the 
axillary vein, to the sheath of which they are adherent. Occasionally one or several 
of these glands are found beneath the vein. Some of the vessels from these glands 
pass into the central group of lymph-nodes; others enter the subclavian glands; 
others pass above the clavicle and terminate in glands situated in that region. 2. 
An anterior group, the thoracic chain, called also the pectoral glands. One mass of this 
chain, the supero-internal, is situated in the second or third intercostal space in 
front of the long thoracic artery and beneath the lower edge of the great Pectoral 
muscle. Another mass, the infero-external, is situated in the fourth and fifth 
intercostal spaces along the course of the long thoracic artery. The vessels from 
this chain end in the central group, and some few of them in the subclavian glands. 
3. A posterior group, the scapular chain, lying along the dorsalis scapulae artery in the 
groove between the Teres major and the Subscapularis muscles. They send vessels 
1 The Lymphatics. Translated and edited by Cecil H. Leaf. THE LYMPHATIC GLANDS OF THE UPPER EXTREMITY 
791 
to the humeral and central chains. 4. A central group, the intermediate glands, placed 
near the base of the axilla, between the previously described chains. Their efferent 
Fig. 497.-Lymphatics of the antero-lateral portion of the thorax. (Sappey.) 
vessels end in the subclavian glands. The glands of the central group in many indi- 
viduals protrude through the opening in the axillary fascia known as the foramen 
SU PRA- 
CLAVICULAR 
LINE OF THE 
CLAVICLE 
SUBCLAVIAN 
HUMERAL 
-CENTRAL GROUP 
SUPERO-INTERNAL 
-PORTION OF 
THORACIC CHAIN 
SCAPULAR 
CHAIN 
IN FERO-EXTERNAL 
■ PORTION OF 
THORACIC CHAIN 
Fig. 498.--Scheme of the axillary glands. The dotted line indicates the position of the clavicle. 
(Poirier and Charpy.) 
of Langer (Fig. 313). 5. A subclavian group, situated above the upper margin 
of the lesser Pectoral muscle. Most of them are internal to the axillary vein, 792 
THE LYMPHATIC SYSTEM 
" between this vein and the first digitation of the Serratus magnus."1 The humeral 
chain and the thoracic chain come together and form the subclavian group of 
glands situated at the apex of the axilla. From the axillary glands come many 
vessels which, by anastomosing, form the infraclavicular plexus, they then unite 
into a trunk, the subclavian trunk, which courses between the subclavian vein and 
Subclavius muscle. On the right side it empties into the junction of the internal 
jugular and subclavian vein or unites with the jugular trunk to form the right 
lymphatic duct. On the left side it may empty into the venous junction or into 
the thoracic duct. 
The Lymphatic Vessels of the Upper Extremity (Figs. 495, 496, 497, 498, 499). 
The lymphatic vessels of the upper extremity are divided into the superficial 
and the deep. 
The Superficial Lymphatic Vessels of the Upper Extremity.-The superficial 
vessels begin as plexuses in the skin and form vessels which ascend in the sub- 
cutaneous tissue. These plexuses are particularly plentiful in the palm and 
palmar surface of the digits (Fig. 499). On each side of each finger two lymph- 
Fig. 499.-Superficial lymphatics of the digits and of the dorsal aspect of the hand. (Cunningham.) 
vessels are formed; they ascend toward the hand, cross the dorsum, and anas- 
tomose frequently with each other. The vessels from the dorsum of the hand 
join the lymph-vessels of the forearm, which ascend chiefly along the superficial 
veins. The lymph-vessels which ascend with the superficial ulnar vein pass into 
the supratrochlear gland. The vessels which accompany the median veins pass 
into the ante-cubital or supratrochlear glands. Some of the lymph-vessels on 
the radial side of the forearm run up along the cephalic vein. All the other 
lymph-vessels of the upper extremity pass direct to the axillary glands. In the 
forearm there are about thirty vessels, in the middle of the arm there are from 
fifteen to eighteen (Sappey). 
The Deep Lymphatic Vessels of the Upper Extremity.-The deep lymph- 
vessels convey the lymph from bone, periosteum, muscle, ligament, etc. They pass 
up the limb with the chief vessels, there usually being two trunks to each arterv. 
In the arm there are two or three vessels. Some few vessels terminate in the 
small glands along the radial, ulnar, and brachial arteries, but most of them pass 
directly to the axillary glands. 
Surgical Anatomy.-In malignant diseases, or other affections implicating the upper part of 
the back and shoulder, the front of the chest and mamma, the upper part of the front and side 
of the abdomen, or the hand, forearm, or arm, the axillary glands are liable to be found enlarged. 
In secondary syphilis the supratrochlear gland is found to be enlarged. This gland is sub- 
cutaneous and readily palpable when enlarged. Normal axillary glands cannot be palpated. 
The Lymphatics. By Poirier, Cuneo, and Delamare. Translated and edited by Cecil H. Leaf. THE LYMPHATIC GLANDS OF THE LOWER EXTREMITY 
793 
The axilla is a passage-way for structures between the neck and the upper extremity, and puru- 
lent collections or tumors may extend from the neck into the axilla or from the axilla into the 
neck. 
The axillary glands are involved early in cases of cancer of the mammary gland, and later 
the lower deep cervical glands are involved, and, as Snow has pointed out, regurgitation of 
lymph containing cancer cells leads to retrosternal involvement and to secondary cancer of the 
head of the humerus. In operating for cancer of the breast, follow the principle of Halsted and 
remove the breast, the skin over it, the muscles and fascia, the lymph-vessels, and the axillary 
glands in one piece. By this plan thorough removal is possible, and as lymph-vessels containing 
carcinoma cells are not cut across, the wound is not grafted with malignant epithelial cells. Dis- 
eased axillary glands are apt to adhere to the sheath of the vein. In removing cancerous glands, 
always excise the sheath of the vein. 
THE LYMPHATICS OF THE LOWER EXTREMITY. 
The Lymphatic Glands of the Lower Extremity. 
The lymphatic glands of the lower extremity are divided into two sets, super- 
ficial and deep. The superficial are confined to the inguinal region, forming the 
superficial inguinal lymphatic glands. 
The Superficial Inguinal Lymphatic Glands (lymphoglandulae inguinale# 
superficiales) (Figs. 500, 501, 502, and 503).-The superficial inguinal lymphatic 
glands, placed immediately beneath the integument in Scarpa's triangle, are of 
SUPERIOR 
EXTERNAL 
GROUP 
SUPERIOR 
.INTERNAL 
GROUP 
I N FERIOR 
INTERNAL 
GROUP 
IN FERIOR 
EXTERNAL 
GROUP 
Fig. 500.-Superficial inguinal glands. Cribriform fascia has been removed so as to expose the femoral 
vessels. (Poirier and Charpy.) 
large size, and vary in number from ten to twenty. It is customary to divide 
these glands into groups according to the region in which they are found. The 
following division is suggested by Poirier, Cuneo, and Delamare:1 A horizontal 
line carried through the saphenous opening divides the glands into two groups, 
a superior group and an inferior group. A vertical line through the saphenous 
opening divides each of the two groups into two secondary groups, an external and 
an internal group. We thus have an external and superior group, and internal and 
superior group, an external and inferior group, and an internal and inferior group. 
1 The Lymphatics. Translated and edited by Cecil H. Leaf. 794 
THE LYMPHATIC SYSTEM 
Directly in the saphenous opening there are often several glands constituting a 
central group. 
Leaf points out that a gland usually exists near the saphenous opening, which 
is interposed between the superficial inguinal and deep inguinal glands. The 
superior group of glands, sometimes called the oblique group, is so placed that the 
glands lie with a certain regularity along and below Poupart's ligament, the long 
axis of each gland corresponding with the direction of the ligament. It is now 
known that each group of the superficial glands does not receive with regularity 
the lymph from and only from a definite and accurately determined area. Hence, it 
is not possible, as was once taught, to determine with certainty the exact situation 
of a lesion by the group of superficial glands involved. The superficial inguinal 
glands receive vessels from the skin of the lower extremity, gluteal region, peri- 
Fig. 501.-Glands of the inguinal region with the afferent and efferent lymphatics. (Poirier and Charpy.) 
neum, abdominal wall, scrotum, anus, and from the prepuce of the clitoris and 
penis. Occasionally, though not normally, they receive vessels from the glans 
penis and glans clitoris. The superficial glands send vessels to the deep inguinal 
glands and to the external iliac glands, and these vessels penetrate the femoral 
sheath. The vessels which go to the iliac glands ascend with the femoral vessels. 
Leaf1 figures some of the efferent vessels from these glands as terminating directly 
in the veins of this region. 
Surgical Anatomy.-The superficial inguinal glands frequently become enlarged in diseases 
implicating the parts from which their lymphatics originate. Thus, in malignant or syphilitic 
affections of the prepuce and penis, or of the labia majora in the female, in cancer scroti, in 
abscess in the perinseum, and in other diseases affecting the integument and superficial structures 
1 The Surgical Anatomy of the Lymphatic Glands, 1898. THE LYMPHATIC GLANDS OF THE LOWER EXTREMITY 
795 
in those parts, or the subumbilical part of the 
abdominal wall or the gluteal region, the upper 
chain of glands is almost invariably enlarged, the 
lower chain being implicated in diseases affecting 
the lower limb. 
The Deep Lymphatic Glands of the 
Lower Extremity.-The deep glands are 
the inguinal, anterior tibial, popliteal, gluteal, 
and ischiatic. 
The Deep Inguinal or Deep Femoral 
Lymphatic Glands (lymphoglandidae in- 
guinales projundae) (Fig. 503).-The deep 
inguinal lymphatic glands are beneath the 
deep fascia. There are only two or three of 
them, and they lie to the inner side of the 
femoral vein, the upper gland being in the 
crural canal and projecting into the pelvis. 
It is called the gland of Cloquet or the 
gland of Rosenmuller. The deep inguinal 
glands receive vessels from the superficial 
inguinal glands, deep lymphatics from 
along the femoral vessels, and vessels from 
the glans penis or clitoris. They send 
vessels to the ilio-pelvic glands. 
The Anterior Tibial Gland (lymph o- 
glandula tibialis anterior) (Fig. 503).-The 
anterior tibial gland is not constant in its 
existence. It is generally found by the 
side of the anterior tibial artery, upon the 
interosseous membrane at the upper part 
of the leg. Occasionally, two glands are 
found in this situation. It receives a deep 
anterior tibial lymphatic trunk and sends 
off a vessel to the popliteal glands. 
The Popliteal Glands (lymphoglandulae 
popliteae).-The popliteal glands are em- 
bedded in the cellular tissue and fat of 
the popliteal space and about the perineal 
vessels The juxta-articular gland receives 
lymph-vessels from the knee-joint. The 
popliteal glands send vessels to the super- 
ficial and deep inguinal glands. 
The popliteal glands are divided into 
three groups:1 1. A gland external to the 
termination of the external saphenous 
vein, the external saphenous gland. 2. A 
middle group of three or four glands on 
the sides of the popliteal vessels. The 
inferior glands of this group are the inter- 
condyloid glands of Leaf. The superior 
glands are the supracondyloid glands of 
Lear. 3. A gland adherent to the posterior 
Superficial 
inguinal 
glands. 
1 The Lymphatics. By Poirier, Cun6o, and Delamare. 
Translated and edited by Cecil H. Leaf. 
Fig. 502.-The superficial lymphatics and glands 
of the lower extremity. 796 
THE LYMPHATIC SYSTEM 
ligament of the knee-joint, the juxta-articular gland of Poirier and Cun6o. The ex- 
ternal saphenous gland receives vessels which ascend along the external saphenous 
INFRACLAVICULAR 
•INFRACLAVICULAR 
EXTERNAL AXILLARY" 
ANTERIOR AXILLARY 
POSTERIOR AXILLARY- 
-SUPRATROCHLEAR 
ANTECUBITAL 
% 
PUBIC 
-SUPERFICIAL FEMORAL 
DEEP FEMORAL 
rURETHRAL 
ANTERIOR TIBIAL 
Fig. 503.-Superficial lymphatic vessels of the trunk, and the lymphatic glands and vessels, superficial and 
deep, of the limbs (diagrammatic). Afferent vessels are represented by continuous lines; efferent and inter- 
glandular vessels by dotted lines. (Cunningham.) THE ILIAC OR ILIO-PELVIC GLANDS 
797 
vein. The middle group receives vessels from the anterior tibial glands and deep 
lymphatic vessels which ascend with the posterior tibial. 
The Gluteal and Ischiatic Glands.-The gluteal and ischiatic glands are placed, 
the former above, the latter below, the Pyriformis muscle, resting on their corre- 
sponding blood-vessels as they pass through the great sacro-sciatic foramen. 
The Lymphatic Vessels of the Lower Extremity (Figs. 502, 503). 
The lymphatic vessels of the lower extremity, like the veins, may be divided 
into two sets, superficial and deep. 
The Superficial Lymphatic Vessels of the Lower Extremity.-The superficial 
lymphatic vessels are placed beneath the integument in the superficial fascia, and 
are divisible into three sets: trunks which follow the course of the internal 
saphenous vein, trunks which accompany the external saphenous vein, and 
trunks from the gluteal region. 1. Trunks which follow the course of the 
internal saphenous vein arise from a plexus on the dorsum of the foot, which 
plexus obtains lymphatics from all the toes, the sole, and both borders of the foot. 
The internal trunks, three or four in number, pass to the superficial inguinal 
glands. Theexternal trunks run upward and inward and end in the internal trunks. 
2. The trunks which follow the external saphenous vein number two or three, and 
they take origin from the heel and from the posterior half of the outer edge of 
the foot. They empty into the superficial inguinal glands. 3. The lymph-trunks 
from the gluteal region join vessels from the anus and enter the superficial 
inguinal glands. 
The Deep Lymphatic Vessels of the Lower Extremity.-The deep lymphatic 
vessels of the lower extremity are few in number and accompany the deep blood- 
vessels. In the leg they consist of three sets, the anterior tibial, peroneal, and 
posterior tibial, which accompany the corresponding blood-vessels, two or three 
to each artery; they ascend with the blood-vessels and enter the lymphatic glands 
in the popliteal space; the efferent vessels from these glands accompany the femoral 
vein and join the deep inguinal glands; from these glands vessels pass beneath Pou- 
part's ligament and communicate with the chain of glands surrounding the exter- 
nal iliac vessels. The deep lymphatic vessels of the gluteal and ischiatic regions 
follow the course of the blood-vessels, and join the gluteal and ischiatic glands at 
the great sacro-sciatic foramen. 
THE LYMPHATICS OF THE PELVIS AND ABDOMEN. 
The lymphatics of the pelvis and abdomen constitute a continuous chain, but 
for convenience of study it is customary to divide them into two groups, which 
we call, with Poirier and Cun^o,1 the ilio-pelvic glands and the abdomino-aortic 
glands; the first group being below and the second above the level of the bifurca- 
tion of the aorta into the two common iliac arteries. 
The Iliac or Ilio-pelvic Glands (Lymphoglandulae Iliacae) (Figs. 504, 505). 
The ilio-pelvic glands are at the level of the inlet of or in the cavity of the 
pelvis. They follow the course of the blood-vessels and are divisible into the 
external iliac, the internal iliac, and the common iliac chains. 
The External Iliac Glands.-The external iliac glands form chains around 
the external iliac vessels. There are three chains of these glands. An external 
chain of three or four glands lies between the artery and the Psoas muscle. 
1 Treatise on Human Anatomy. THE LYMPHATIC SYSTEM 
798 
The lowest gland of the external chain is called by Poirier and Cun^o the external 
retro-crural gland (Fig. 504). A middle chain of three glands lies upon the front 
surface of the external iliac vein. The lowest gland of this group is called bv 
Poirier and Cuneo the middle retro-crural gland. An internal chain of three or 
four glands is placed to the inner side of the external iliac vein. The lowest gland 
of this chain is called the internal retro-crural gland, and is close to the upper gland 
of the deep inguinal chain, the gland of Cloquet. The obturator gland belongs to 
the inner chain of external iliac glands. The external iliac glands receive vessels 
from the superficial and deep iliac glands, from the glans penis or glans clitoris, 
RIGHT JUXTA 
AORTIC 
LEFT JUXTA 
AORTIC 
COMMON 
ILIAC 
PROMONTORY 
COMMON ILIAC 
COMMON ILIAC 
(middle group) 
EXTERNAL ILIAC 
EXTERNAL I LIAC 
(external chain) 
EXTERNAL ILIAC 
(middle chain) 
OBTURATOR 
NERVE 
OBTURATOR 
ARTERY 
EXTERNAL 
RETROCRURAL 
OBTURATOR 
ARTERY 
OBTURATOR 
GLAND 
Fig. 504.-Ilio-pelvic glands. (Poirier and Charpy.) 
deep lymphatics from the umbilicus and lower part of the belly wall, vessels from the 
superior portion of the vagina, the uterine neck, the prostate gland, the bladder, 
the membranous portion of the urethra, and the internal iliac glands, and the 
obturator gland receives deep lymph-vessels from along the course of the obtu- 
rator vessels. The external iliac glands send vessels direct to the common iliac 
glands and also lymphatics to join vessels from the internal iliac glands on their 
way to the common iliac group. The glands along the deep epigastric artery 
and those along the deep circumflex iliac artery are accessory chains to the main 
group of external iliac glands. THE ABDOMINO-AORTIC GLANDS 
799 
The Internal Iliac or Hypogastric Glands.-The internal iliac glands are 
placed along the internal iliac artery and its branches. The gland on the middle 
hsemorrhoidal artery is called the middle hsemorrhoidal gland. The lateral sacral 
gland is on the lateral sacral artery. The internal iliac glands receive lymph from 
the pelvic viscera, perinseum, and penile portion of the urethra, deep tissues of the 
posterior portion of the thigh, and from the buttocks. They send vessels to the 
common iliac glands and also to the external iliac glands. 
The Common Iliac Glands.-The common iliac glands are found about the 
common iliac artery and are divided into an external group, which lies upon the 
INTERPELViC 
GLUTEAL 
PROMONTORY 
LATERAL 
SACRAL 
EXTERNAL ILIAC 
(middle chain) 
EXTERNAL ILIAC 
(middle chain) 
HYPOGASTRIC 
HYPOGASTRIC 
EXTERNAL ILIAC 
(external chain) 
RETROCRURAL 
SATELLITE TRUNK 
OF INTERNAL 
PUDIC VESSELS 
EXTERNAL 
RETROCRURAL- 
INTERNAL 
LYM PHATICS 
OF BLADDER 
TRUNK OF 
MIDDLE HEMOR- 
RHOIDAL VESSELS 
LYMPHATIC FROM- 
GLANS PENIS 
LY M PH ATICS 
OF BLADDER 
PROSTATIC COL- 
LECTING TRUNK 
URETHRAL COL- 
LECTING TRUNKS 
LYMPHATIC GLANDULAR NODULE 
IN FRONT OF SYMPHYSIS 
PROSTATIC COL- 
LECTING TRUNK 
Fig. 505.-Ilio-pelvic glands (lateral view.) (Poirier and Charpy.) 
inner edge of the Psoas muscle; a middle group, behind the artery, and an internal 
group, which lies upon the front of the body of the fifth lumbar vertebra or upon 
the sacro-vertebral junction. They receive vessels from the external and internal 
iliac glands and from the pelvic viscera, the vessels from the pelvic viscera ascend- 
ing to the promontory of the sacrum and containing perhaps, here and there, 
interrupting glands, known as sacral glands {lymphoglandulae sacrales) (Fig. 511). 
They also receive lymph-vessels from the lumbo-sacral region. They send vessels 
to the aortic glands. Some anatomists place the common iliac glands and the 
glands about the lower portion of the aorta and vena cava in a group called the 
lumbar glands (lymphoglandulae lumbales) (Fig. 511). 
The abdomino-aortic glands are placed about the abdominal aorta. There are 
twenty-five or thirty of them. They are divided by Poirier, Cuneo, and Delamare1 
The Abdomino-aortic Glands (Figs. 484, 511). 
' The Lymphatics. Translated and edited by Cecil H. Leaf. THE LYMPHATIC SYSTEM 
800 
into the right and left juxta-aortic glands, the retro-aortic glands, and the pre-aortic 
glands. 
The Right Juxta-aortic Glands.-The right juxta-aortic glands are grouped 
in front of and behind the inferior vena cava, the posterior glands lying upon the 
Psoas muscle and the adjacent pillar of the Diaphragm. They receive lymph- 
vessels from the right common iliac glands, from the right testicle or the right 
half of the uterus, and the right tube, ovary, broad ligament, the right kidney 
and suprarenal capsule, and also lymph-vessels which pass along the lumbar 
arteries. They send vessels to the pre-aortic and the retro-aortic glands and the 
receptaculum chyli. 
The Left Juxta-aortic Glands.-The left juxta-aortic glands lie by the side of 
the abdominal aorta, upon the Psoas muscle, and the left pillar of the Diaphragm. 
They receive tributaries from the left side corresponding to those received by 
the glands of the right side, and also send out corresponding efferent vessels, and 
several additional vessels which pass through the left pillar of the Diaphragm and 
empty into the thoracic duct. 
The Retro-aortic Glands.-The retro-aortic glands are placed beneath the 
receptaculum chyli and in front of the bodies of the fourth and fifth lumbar ver- 
tebrae. They receive lymph-vessels from both juxta-aortic groups, and also from 
the pre-aortic glands, and they send vessels to the receptaculum chyli. 
The Pre-aortic Glands.-The pre-aortic glands lie upon the front of the aorta, 
and in most subjects are divisible into three groups: an inferior, lying at the origin 
of the inferior mesenteric artery; a middle, at the origin of the superior mesenteric 
artery, and a superior, about the cceliac axis, the cceliac glands (lymphoglandulae 
coeliacae). Glands which are found along the course of all the branches of the 
abdominal aorta empty into and belong to the group of pre-aortic glands. The 
pre-aortic glands receive vessels from the juxta-aortic glands and from all the 
glands along the mesenteric vessels and the cceliac axis and its branches, 
and receive lymph from the stomach, intestines, liver, pancreas, and spleen. 
They anastomose with each other and send vessels to the retro-aortic glands and 
to the receptaculum chyli. Instead of the glands terminating in the receptaculum 
by separate vessels, the vessels may unite and form a common trunk, the intes- 
tinal trunk (truncus intestinalis), which runs along with the common trunk from 
the juxta-aortic glands, and empties into the receptaculum (Fig. 484). 
1. The Glands along the Mesenteric Arteries (lymphoglandulae mesentericae) receive 
the lymph from the colon, caecum, appendix, ileum, jejunum, duodenum, and 
perhaps also some from the stomach. 
2. The Glands Connected with the Cceliac Axis and its Branches.-There are three 
groups of these glands: the gastric or coronary, the splenic, and the hepatic (in- 
cluding those of the bile-ducts). 
The Gastric Glands {lymphoglandulae gastricae).-One group is situated in the 
gastro-pancreatic fold; another group is connected with the lesser curvature of the 
stomach (Fig. 508). Some of them are in the lesser omentum close to insertion of 
the thicker part upon the stomach, and lie near the ascending branches of the gastric 
artery, that is to say, upon the vertical portion of the lesser curvature. Others lie 
within the lesser omentum and accompany the descending branches of the gas- 
tric artery, and particularly gather near the point where the gastric artery comes 
toward the stomach wall. The gastric glands receive lymph from most of the 
stomach. They send lymph to the upper group of pre-aortic glands, the cceliac 
glands. 
The Splenic Glands (lymphoglandulae pancreaticolienales').-The splenic glands 
accompany the splenic artery and lie upon the posterior surface of the spleen, 
between the spleen and pancreas. They receive lymph from the fundus of the 
stomach, from the spleen, and from the pancreas, and send it to the cceliac glands. THE LYMPHATIC VESSELS OF THE ABDOMEN AND PELVIS 
801 
The Hepatic Glands {lymphoglandulae hepaticae).-These glands lie along the 
hepatic artery, some on the level of the floor of the foramen of Winslow, others by 
the left side of the portal vein.1 The authors previously quoted point out that there 
is a secondary chain of hepatic glands about the right gastro-epiploic artery, the 
gastro-epiploic chain, and that this comprises a subpyloric group and a retro-pyloric 
group. The subpyloric group (Fig. 508) is placed in the great omentum below the 
pylorus, and is usually distinctly separated from it. The retro-pyloric group is not 
constant. It is placed along the gastro-duodenalis artery back of the pylorus. 
There is also a group of glands, secondary to the hepatic glands, to the right of 
or posterior to the cystic duct and the common bile-ducts. The hepatic glands 
proper receive lymph from the liver and send it to the coeliac glands. The 
subpyloric glands receive lymph from the inferior portion of the stomach and 
from the superior portion of the great omentum. They send lymph to the hepatic 
glands proper, the retro-pyloric glands, and sometimes also to the glands about 
the superior mesenteric artery. The retro-pyloric glands receive lymph from the 
subpyloric glands, from the upper surface and from the posterior surface of 
the pylorus, and from the duodenum. They send lymph to the hepatic glands 
proper and sometimes to the glands along the superior mesenteric artery. The 
glands along the gall-ducts empty into the hepatic glands proper. 
The Lymphatic Vessels of the Abdomen and Pelvis. 
The lymphatic vessels of the abdomen and pelvis may be divided into two sets, 
superficial and deep. 
The Superficial Lymphatic Vessels of the Walls of the Abdomen.-The 
superficial lymphatic vessels of the walls of the abdomen follow the course of the 
superficial blood-vessels. The superficial lymphatics are derived from the integu- 
ment. Those of the lower part of the abdomen below the umbilicus follow the course 
of the superficial epigastric vessels and converge to the superior group of the super- 
ficial inguinal glands (Figs. 501 and 503). Those from the costal margins of the 
abdomen terminate in the axillary glands (Fig. 497). The superficial lymphatics 
from the sides of the lumbar part of the abdominal wall wind around the crest of 
the ilium, accompanying the superficial circumflex iliac vessels, to join the super- 
ficial inguinal glands (Fig. 501). 
The Superficial Lymphatic Vessels of the Gluteal Region.-The superficial lym- 
phatic vessels of the gluteal region turn horizontally around the outer side of the 
nates, and join the superficial inguinal glands. 
The Superficial Lymphatic Vessels of the Scrotum and Perinseum.-The superficial 
lymphatic vessels of the scrotum and perinseum terminate in the superficial inguinal 
glands. 
The Superficial Lymphatic Vessels of the Penis.-The superficial lymphatic vessels 
of the penis occupy the sides and dorsum of the organ, the latter receiving the 
lymphatics from the prepuce; thev all converge to the superficial inguinal glands. 
Lymph vessels from the glans penis empty into the deep inguinal and the external 
iliac glands. 
In the female the lymphatic vessels of the vulva and prepuce of the clitoris pass 
to the superficial inguinal glands; those of the glans of the clitoris pass to the 
deep inguinal and the external iliac glands. 
The Deep Lymphatic Vessels of the Abdominal Wall.-The deep lymphatic 
vessels of the abdominal wall take the course of the principal blood-vessels, and 
arise from muscular or aponeurotic layers. One set of lymph-vessels runs along 
with the deep epigastric artery and terminates in the external iliac glands. Another 
1 The Lymphatics. By Poirier, Cuneo, and Delamare. Translated and edited by Cecil H. Leaf. 802 
THE LYMPHATIC SYSTEM 
accompanies the deep circumflex iliac artery, and also terminates in the external 
iliac glands. Several lymph-vessels accompany the lumbar arteries and empty 
into the juxta-aortic glands. A vessel accompanies the internal mammary artery 
and empties into the internal mammary glands. Lymph-vessels of the parietes of 
the pelvis, which accompany the gluteal, ischiatic, and obturator vessels, follow 
the course of the internal iliac artery, and ultimately join the external iliac, internal 
iliac, and common iliac glands, and the glands about the lower portions of the aorta 
and vena cava. 
The Lymphatic Vessels of the Umbilicus.-The lymphatics of the umbilicus are 
divided into three groups:1 The cutaneous lymphatics, which are very superficial, 
and empty into the superficial inguinal glands. The lymphatics of the fibrous 
nucleus, which pass through the rectus sheath, reach the deep epigastric artery 
and join the deep lymphatics which come from the muscular and aponeurotic 
layers of the belly wall. The lymphatics of the aponeurotic margin are in two sets: 
An anterior set, some of which penetrate the rectus sheath and join the lymphatics 
from the fibrous nucleus; others of which pass outward, penetrate the external and 
internal oblique muscles, and join the posterior lymph-vessels from the aponeu- 
rotic margin. A posterior set, which forms a collection of vessels on the posterior 
aspect of the rectus sheath, from which several trunks emerge. One trunk passes 
outward, penetrates the Transversalis muscle, joins the anterior trunk from the 
aponeurotic margin, and empties into the external iliac glands.2 Other ducts run 
along with the deep epigastric artery and pass into the external iliac glands. 
Glands lie along the lower portion of these lymph-ducts, and are known as 
the superior epigastric glands, and a gland may exist in the subperitoneal tissue 
beneath the umbilicus. 
The Lymphatic Vessels of the Peritoneum.-It seems probable that the peritoneal 
cavity is a lymph-sac and that lymphatics take origin from the peritoneum in 
several ways. Byron Robinson3 points out three modes of origin: 1. By stomata 
between endothelial cells. These stomata are in direct communication with 
lymph-vessels. 2. By interstitial spaces in the subperitoneal tissue. 3. By a 
plexiform origin similar to interstitial spaces. 
Surgical Anatomy.-The fact emphasized by Byron Robinson that the peritoneum is a great 
lymph-sac explains the quick absorption of septic material and the rapid spread of infectious pro- 
cesses. If the exudate clots and blocks the lymph-channels, absorption is slow and life may be 
saved. If it does not clot, absorption is rapid and death is certain. Whether it clots or not 
depends on the nature of the bacteria present.4 Fowler, impressed by the fact that absorption 
takes place most rapidly from the diaphragmatic region and least rapidly from the pelvic region, 
advises placing the victim of peritonitis in bed, with his head and body elevated? 
The Lymphatic Vessels of the Bladder.-No lymphatics exist in the mucous mem- 
brane of the bladder, although they do exist in the mucous membrane of the pros- 
tate. There are some lymphatics in the bladder muscle, and numerous lymphatics 
in the subperitoneal tissue. The network of lymph-vessels in the muscles is con- 
nected with the network beneath the peritoneum and prevesical fascia, and collect- 
ing trunks come from both the anterior and posterior surfaces of the bladder. 
The anterior collecting trunks are divided into two sets. One set comes from the 
inferior portion of the anterior surface and passes outward to terminate in an 
external iliac gland "between the external iliac vein and the obturator nerve."6 
The other set comes from the superior and anterior vesical surface, runs upward 
and outward, and terminates in the external iliac glands. Each set of vessels 
possesses interrupting lymph-nodes, some of which are directly in front of the 
bladder. 
' The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. 
2 Poirier, CunGo, and Delamare. 3 The Peritoneum. 4 Byron Robinson. The Peritoneum. 
5 George Ryerson Fowler, on Diffuse Septic Peritonitis, in the Medical Record, April 14, 1900. 
6 The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. THE LYMPHATIC VESSELS OF THE ABDOMEN AND PELVIS 
803 
The posterior collecting trunks are divided into four sets. The first set comes 
from the superior and posterior portion and passes outward, exhibiting interrupting 
nodes in its course. These trunks terminate in the external iliac glands. The 
second set runs directly back into the external iliac glands. The third set comes 
from the middle of the posterior portion of the bladder and terminates in the 
hypogastric glands. The fourth set comes from the vesical neck, passes back 
and then ascends and terminates in the glands in front of the sacral promontory. 
This fourth set joins with the lymphatics from the prostate and seminal vesicles. 
The Lymphatic Vessels of the Prostate Gland.-These vessels form a peri-pros- 
tatic plexus, which receives its afferents from the gland structure. This plexus is 
drained by four vessels, three of which commence on the posterior surface of the 
gland. Although these vessels begin on the posterior surface of the prostate, their 
termination in each case is different. One passes on the under surface of the 
bladder, crosses the superior vesical artery, runs outward, and ends in the middle 
chain of the external iliac group. Another passes upward, outward, and back- 
ward, and terminates in the hypogastric group. A third passes along the 
floor of the pelvis, runs by the side of the rectum, and ascends on the anterior 
surface of the sacrum to terminate in the lateral sacral glands and in the hypo- 
gastric group. Occasionally a fourth trunk is found on the anterior surface of 
the prostate, which descends and joins the vessels from the membranous urethra 
and ends in the hypogastric glands. 
The Lymphatic Vessels of the Male Urethra.-These vessels are divided into two 
groups: First, those of the penile portion of the urethra; second, those of the bulb 
and membranous portion. The lymphatics of the prostatic urethra belong to those 
of the prostate gland. The lymph-vessels of the penile urethra in front of the 
sulcus all run toward the fraenum, at which point they bend backward to the sul- 
cus; here they run to the dorsal surface of the penis and terminate in the same man- 
ner as the vessels from the glans. The trunks from the remainder of the penile 
urethra emerge from the inferior surface, run around the corpus cavernosa, and 
mostly unite with the vessels from the glans penis. One vessel, though, passes over 
the symphysis and enters in the internal retro-crural gland, whilst another passes 
beneath the symphysis and terminates with the vessels from the bulb and mem- 
branous portion of the urethra. The lymphatics of the bulb and membranous 
portions end in three trunks, one of which accompanies first the artery of the bulb 
and then the internal pudic artery, and ends in the hypogastric gland attached to 
the pelvic portion of this artery. A second trunk runs behind the pubes, to end 
in the internal retro-crural gland. A third trunk runs on the bladder, where it 
joins with vessels from this organ, to end in the internal chain of external iliac 
glands. 
The Lymphatic Vessels of the Female Urethra.-The lymphatics of the female 
urethra terminate in the same manner as do the lymphatics of the bulb and mem- 
branous portions of the male urethra 
The Lymphatic Vessels of the Uterus.-These consist of three sets, each of which 
arises by a network of capillaries. There is a mucous network, a muscular network, 
and a peritoneal network. The vessels from these three regions of origin are col- 
lected in the subperitoneal tissue, from which area the collecting trunks take origin. 
From the cervix, according to Poirier and Cuneo, come from five to eight collecting 
trunks, which pass toward the sides of the body of the uterus, forming on each 
side, by twisting and dilatation, the juxta-cervical lymphatic knot of Cuneo. The 
cervical connecting trunks are divisible into three groups on each side. One group 
is composed of two vessels, which pass to the middle chain of the external iliac 
glands (superior and middle glands). Another group is composed of two vessels, 
which enter the hypogastric glands. A third group is composed of several vessels, 
some of which enter the lateral sacral glands, and the balance of which terminate 804 
THE LYMPHATIC SYSTEM 
in the glands of the sacral promontory. From the body of the uterus come three 
groups on each side. One group is composed of four or five vessels which emerge 
below the uterine cornu, pass beneath the ovary, where they receive the ovarian 
lymphatics, and terminate in the juxta-aortic glands of the same side. One 
so-called accessory lymphatic pedicle terminates in the external iliac glands, the 
other in the inguinal glands. 
The Lymphatic Vessels of the Fallopian Tube.-The lymphatics of the Fallopian 
tube join with those of the uterus and ovary and terminate in the lateral aortic 
glands. 
The Lymphatic Vessels of the Ovary.-The ovary is extremely rich in lymphatics; 
they form a plexus which is superficial to the veins. The vessels leading from this 
plexus, four or five in number, pass upward in company with the ovarian vessels 
and end in the lateral aortic glands. Above the fifth lumbar vertebra these ves- 
sels anastomose with the lymphatics from the fundus of the uterus and Fallopian 
tube. Quite often there is a lymph-vessel which emerges from the ovary, passes 
downward and outward and ends in the middle chain of the internal iliac glands. 
The Lymphatic Vessels of the Vagina.-The lymphatics of the vagina are divided 
into those of the mucous coat and those of the muscular coat; these anastomose 
freely with each other and terminate in a peri-vaginal network, which is drained 
by three groups of trunks. One group drains the upper third of the vagina and 
passes to the middle chain of the external iliac glands. A second group is efferent 
to the middle third of the vagina and ends in the hypogastric glands. A third 
group carries the lymph from the lower third of the vagina to the gland of the 
promontory. 
The Lymphatic Vessels of the Testicle.-The lymphatic vessels of the testicle 
consist of two sets, superficial and deep; the former commence on the visceral sur- 
face of the tunica vaginalis, the latter in the epididymis and body of the testis. 
They form several large trunks which ascend with the spermatic cord, and, accom- 
panying the spermatic vessels into the abdomen, terminate in the juxta-aortic 
and sometimes also in the pre-aortic glands; hence the enlargement of these glands 
in malignant disease of the testis. 
The Lymphatic Vessels of the Vas Deferens.-These lymphatics empty into the 
external iliac glands. 
The Lymphatic Vessels of the Seminal Vesicles.-A network exists on the surface 
of each vesicle, formed by a collection of lymph-vessels from the mucous lining and 
from the muscular structure of the vesicle. The trunks from this network empty 
into the external and internal iliac glands. 
The Lymphatic Vessels of the Kidney, Ureter, and Suprarenal Capsule.-Their 
courses and terminations differ on the two sides. They take origin from a super- 
ficial network just beneath the capsule of the kidney and a deep network in the in- 
terior of .the organ. The superficial network is connected to the collecting vessels 
of the deep network at the hilum. From the superficial network numerous ves- 
sels penetrate the capsule of the kidney and join the lymphatics of the fatty cap- 
sule. According to Poirier, Cun^o, and Delamare,1 anterior and posterior trunks 
come off from the deep lymphatics of the right kidney. The anterior trunk 
usually terminates in the right juxta-aortic glands which lie upon the vena cava. 
The posterior trunks terminate in the juxta-aortic glands which lie behind the 
vena cava. On the left side all the collecting trunks terminate in the juxta-aortic 
glands of the left side of the aorta. 
The lymphatics of the fatty capsule of the kidney communicate with the lym- 
phatics of the kidney, and both terminate in the same glands. The lymphatics of 
the suprarenal capsule terminate in the juxta-aortic glands of the same side. From 
The Lymphatics. Translated and edited by Cecil H. Leaf. THE LYMPHATIC VESSELS OF THE ABDOMEN AND PELVIS 
the ureter lymph-vessels come off and terminate in the juxta-aortic and adjacent 
glands. 
The Lymphatic Vessels of the Liver.-The lymphatic vessels of the liver are 
divisible into two sets, superficial and deep. The former arise in the lobules at the 
periphery of the liver and pass to the subperitoneal connective tissue over the 
entire organ. The latter arise from the deeper lobules, and emerge from the liver 
along the portal vein or the hepatic veins. 
According to Poirier, Cuneo, and Delamare,1 three groups of superficial collect- 
ing trunks arise from the subperitoneal network. The posterior trunks divide 
into three groups. The single right posterior trunk terminates in a gland about the 
coeliac axis. The middle posterior trunks (five to seven in number) pass through 
the opening in the Diaphragm. The lejt posterior trunks pass into glands 
805 
LEFT LATERAL 
LIGAM ENT 
OBLITERATED 
UMBILICAL VEIN 
Fig. 506.-Lymphatics of the inferior surface of the liver. (Sappey.) 
about the subdiaphragmatic portion of the oesophagus. The anterior collecting 
trunks terminate in the lymph-glands of the hilum of the liver. The superior 
trunks ascend. One of these trunks or a posterior trunk passes with the vena cava 
through the Diaphragm and terminates in glands about the vena cava. Another 
trunk, an anterior one, passes over the anterior border of the liver, runs for a time 
with the round ligament, and terminates in the hepatic glands. Numerous middle 
trunks ascend in the suspensory ligament, unite beneath the Diaphragm into a 
short trunk of large size, which passes through the Diaphragm and divides into 
several smaller ducts, which terminate in the glands back of the xiphoid cartilage. 
Trunks from the superficial lymphatic network also emerge from the inferior 
surface of the liver. The posterior trunks from the right lobe reach the vena cava 
and terminate in the glands about the intra-thoracic end of that vessel. The 
middle and anterior trunks from the right lobe reach the glands along the cystic 
duct. The trunks from the left lobe terminate in the glands along the hepatic 
artery. The trunks from the lobus Spigelii reach the glands of the hilum and the 
glands about the lower intra-thoracic portion of the vena cava. The trunks from 
the quadrate lobe terminate in the glands of the hilum. The deep collecting trunks 
' The Lymphatics. Translated and edited by Cecil H. Leaf. THE LYMPHATIC SYSTEM 
806 
are divisible into two groups. One group descends along the portal vein, the other 
ascends along the hepatic veins. 
Sappey pointed out that the deep descending trunks accompany the bile pass- 
ages and the branches of the portal vein, several anastomosing vessels accom- 
panying each branch of the portal vein. The same authority affirmed that from 
fifteen to eighteen trunks emerge from the hilum and terminate in the adjacent 
glands. The deep ascending trunks surround as a sheath the branches of the 
hepatic vein (Sappey). As they approach the Diaphragm they diminish in num- 
ber to five or six, pass through the opening for the vena cava, and terminate in 
the glands about the lower portion of the intra-thoracic cava. 
The Lymphatic Vessels of the Bile-ducts.-The lymphatics of the bile-ducts arise 
from the mucous membrane and from within the muscular tissue, and terminate 
in glands along the cystic and common ducts. 
The Lymphatic Vessels of the Stomach (Figs. 507 and 508).-The lymphatic 
vessels of the stomach consist of two sets, superficial and deep. The superficial 
arise from the outer (serous) and the middle (muscular) coats. The deep arise 
from the mucous membrane and form a network in the submucous tissue. Trunks 
from the submucous network pass through the muscular tunic and terminate in 
the trunks coming from the sero-muscular layers. These latter, the musculo-serous 
CORONARY, 
CURRENT 
SPLENIC 
CURRENT 
RIGHT 
GASTRO-EPI PLOIC 
CURRENT 
Fig. 507.-Lymphatic areas of the stomach. (Cun£o.) 
collecting trunks, are divided into three groups. The first group is composed of six 
or eight vessels which pass toward the lesser curvature (Sappey). There are from 
three to ten glands upon the lesser curvature along the course of the gastric artery 
which receive these superior trunks. Vessels come to these glands from the cardia, 
from the body of the stomach, and from the pyloric end. In the lesser curvature 
the lymphatic vessels lie in the wall of the stomach. According to Cun^o, two- 
thirds of the stomach is drained by the lymph-vessels of group I. The second 
group comprises the trunks from the greater curvature which end in the subpyloric 
glands. The glands along the greater curvature are some distance from the 
stomach wall in the pyloric region, and lymph-streams flow from left to right, that 
is, toward the pylorus and not from it. These lymphatics drain one-third of the 
stomach. The first and second groups send lymph eventually to the coeliac 
glands and juxta-aortic glands. The third group comprises trunks which come 
from the fundus of the stomach and enter the lymphatic glands about the spleen. 
Surgical Anatomy.-Mikulicz pointed out the early infection of the glands of the lesser curva- 
ture in pyloric cancer, and insisted that in operation for pyloric cancer the entire lesser curvature 
must be removed. Cuneo showed us that in pyloric cancer the fundus and two-thirds of the 
greater curvature usually remain free from disease, because the lymph-current is toward the 
pylorus and not from it. Of course, if the lymphatics become blocked, the lymph-current may 
be reversed (regurgitation), and then infection of these parts can occur. William J. Mayo has 
noted the ''lymphatic isolation" of the dome of the stomach. In operating for cancer of the THE LYMPHATIC SYSTEM OF THE INTESTINES 
807 
pylorus, make the section of the stomach as directed by Hartmann, that is, a section which 
removes all of the lesser curvature and cuts the greater curvature well to the left of the subpyloric 
glands. 
The Lymphatic Vessels of the Pancreas.-The lymphatics of the pancreas arise 
from a network about the pancreatic lobules. The collecting trunks anastomose 
freely on the surface of the pancreas. Some of the trunks terminate in the 
splenic glands, which send vessels to the coeliac glands. Others terminate directly 
in the coeliac glands. The lymphatics of the head of the pancreas communicate 
with the duodenal lymphatics and the lymphatics of the lower end of the com- 
mon duct. The pancreatic and splenic lymphatics probably communicate. 
The Lymphatic Vessels of the Spleen.-The lymphatics of the spleen consist of 
two sets, superficial and deep; the former are placed beneath its peritoneal covering, 
the latter in the substance of the organ; they accompany the blood-vessels, passing 
through a series of small glands, and pass into the splenic glands which are placed 
in the omentum between the spleen and pancreas. The gastro-splenic omentum 
contains no glands. 
THE LYMPHATIC SYSTEM OF THE INTESTINES. 
The Lymphatic Glands of the Small Intestine (Fig. 509).-The lymphatic 
glands of the small intestine are placed between the layers of the mesentery, and are 
PRECARDIAL 
GLAN DS 
LEFT PNEUMO-, 
GASTRIC NERVE 
RIGHT PNEUMO-. 
GASTRIC NERVE 
CORONARY 
ARTERY' 
CORONARY 
vein' 
GLANDS OF THE 
LESSER CURVATURE 
HEPATIC 
ARTERY 
RIGHT GASTRO- 
EPIPLOIC ARTERY" 
SUBPYLORIC, 
GLAND 
RIGHT GASTRO- 
EPIPLOIC VEIN 
Fig. 508.-General view of the subperitoneal lymphatic plexus of the stomach prepared by the method of 
Gerota. (Cun6o.) 
called mesentery glands (lymphoglandulae mesentericae). They vary in number from 
a hundred to a hundred and fifty, and in size from that of a pea to that of a small 808 
THE LYMPHATIC SYSTEM 
almond.1 These glands are most numerous and largest above, the glands of the 
jejunum being more numerous than those of the ileum. This latter group becomes 
enlarged and infiltrated with deposit in cases of fever accompanied with ulceration 
of the intestines. The glands diminish in number as we descend until the ileo- 
caecal region is reached, when a number of glands appear about the ileo-csecal 
artery. The mesenteric glands receive the lacteals and send out trunks to the 
receptaculum chyli. The chyle from the intestine passes through the glands on 
its way to the thoracic duct. 
The glands may be divided into: I. A group of glands the members of which 
are chiefly found along the terminal vessels from the vascular loops of the intestinal 
branches of the superior mesenteric artery. Some glands of this group are placed 
upon "the anterior surface of the upper end of the jejunum."2 II. A group of 
glands along the vascular loops of the superior mesenteric artery. Most of them 
are between the primary loops. Some of them are between the secondary and 
tertiary loops. III. A group of glands along the trunk of the superior mesenteric 
artery. 
Fig. 509.-Lymphatics of the small intestine. (Poirier and Charpy.) 
The Lymphatic Vessels of the Small Intestine (Fig. 509).-The lymphatic 
vessels of the small intestine are called lacteals, from the milk-white fluid they 
usually contain. They take origin in the intestinal villi and in lymphatic sinuses 
around the bases of the solitary glands. Lymphatic plexuses exist in the submucous 
tissue, the muscular coat, and the subserous tissue. The lymphatic vessels pass 
between the layers of the mesentery, enter the mesenteric glands, and finally unite 
to form two or three large trunks which terminate separately in the receptaculum 
chyli; frequently, however, they first unite to form a single large trunk, termed the 
intestinal lymphatic trunk (Figs. 483, 484, and 511). 
The Lymphatic Glands of the Large Intestine.-The lymphatic glands of the 
large intestine are divided into the colic glands and rectal glands. 
The Colic Glands {lymphoglandulae coliacae).-The colic glands are subdivided 
into: 1. The ileo-colic or ileo-ca?cal glands (Fig. 510), which lie along the course 
of the ileo-colic artery, one or two of the glands being placed upon the anterior 
surface of the caecum. The mesoappendix also contains a gland which com- 
' Leaf (Surgical Anatomy of the Lymphatic Glands) says it is very common to find not more than forty or 
fifty. 
2 The Surgical Anatomy of the Lymphatic Glands. By Cecil H. Leaf. THE LYMPHATIC SYSTEM OF THE INTESTINES 
municates with glands in the mesocolon, and receives lymph from the appendix 
and, in the female, from the ovary. 2. Glands in the mesocolon along the right 
colic artery, which receive lymph from the ascending colon and the hepatic flexure. 
3. Glands in the mesocolon along the middle colic artery, which receive lymph 
from the hepatic flexure and transverse colon. 4. Glands in the mesocolon 
along the left colic artery, which receive lymph from the descending colon and 
sigmoid flexure. The vessels from the colic glands pass to the pre-aortic 
glands. 
The Rectal Glands.-The rectal glands lie in the mesorectum; they receive lymph 
from the anus and rectum and it passes from them to the lumbar and sacral glands. 
The Lymphatic Vessels of the Large Intestine.-The lymphatic vessels of the 
large intestine consist of three sets: those of the caecum, ascending and transverse 
809 
ILEOCECAL 
ANTERIOR 
LYM PHATICS 
OF C>ECUM 
ANTERIOR 
C>ECAL 
.GLAND OF 
APPENDIX 
APPENDICULAR 
EFFERENT 
LYMPHATICS 
Fig. 510. -Anterior view of the lymphatics of the caecum and appendix. (Poirier and Charpy.) 
colon, which, after passing through their proper glands, enter the mesenteric 
glands; those of the descending colon and sigmoid flexure, which pass to the lumbar 
glands, and those of the rectum and anus, which pass to the sacral and superficial 
inguinal glands. 
Lymphatics of the Anus and Rectum.-These vessels take origin from two 
networks, one from the skin and mucous membrane and the other from the mus- 
cular coat. The lymph-vessels from the skin at the anal margin pass to the super- 
ficial inguinal glands. Some vessels from the skin of the anus ascend and reach 
the submucous plexus of the rectum, from which region lymph-vessels pass to 
the rectal glands, to the glands along the middle haemorrhoidal artery, and along 
the inferior hemorrhoidal artery, and to a pelvic gland near the origin of the 
internal pudic artery.1 The vessels from the anal mucous membrane and from 
the muscular wall of the rectum penetrate the muscular wall of the rectum 
with the arteries and reach the rectal glands. 
1 The Lymphatics. By Poirier, Cuneo, and Delamare. Translated and edited by Cecil H. Leaf. 810 
THE LYMPHATIC SYSTEM 
THE LYMPHATICS OF THE THORAX. 
The thoracic lymphatics are divided into the deep lymphatics of the chest wall, 
the diaphragmatic lymphatics, and the visceral lymphatics. 
The Lymphatic Glands of the Thoracic Wall or the Parietal Lymphatics. 
The lymphatic glands of the thoracic wall include the internal mammary and 
intercostal glands. 
The Internal Mammary Glands.-The internal mammary, retro-sternal, or 
sternal glands form a chain of five or six glands on each side of the sternum along 
the course of the corresponding internal mammary artery, and back of the Internal 
intercostal muscles. The glands are separated from the pleura by cellular tissue. 
The internal mammary glands receive vessels from the diaphragmatic glands, the 
abdominal muscles above the umbilicus, the anterior ends of the intercostal spaces, 
the skin over the sternum, and the mammary gland. The vessels given off by 
each chain form a single trunk. On the right side this trunk terminates at the 
junction of the internal jugular and subclavian veins, unites with the subclavian 
lymph-trunk to form the right lymphatic duct, or empties directly into the sub- 
clavian trunk (Fig. 486). On the left side it empties either at the junction of 
the subclavian and internal jugular veins or into the thoracic duct. 
The Intercostal Glands (lymphoglandulae intercostales) (Fig. 511).-The inter- 
costal glands are small glands lying in the intercostal spaces along the intercostal 
arteries. In the posterior end of each space they are constantly found. These are 
called the posterior glands, and there are one, two, or three in each space. These 
glands are opposite the neck of the rib or over the articulation of the rib with the 
vertebra. The pleura is in front of them, and they lie upon the external inter- 
costal muscles. In the middle of the intercostal spaces are inconstant glands 
which are called lateral glands. They are merely interrupting nodes in the 
trunks from the intercostal muscles. The intercostal glands receive vessels from 
the intercostal muscles and pleura. They send vessels back toward the spine, 
which unite with lymphatics from the back part of the thorax and spinal canal, 
and which pass down the spine and terminate in the thoracic duct. 
The Diaphragmatic Lymphatics.-The diaphragmatic lymph-glands are dis- 
tinct and numerous. These glands are on the convex surface of the Diaphragm 
and are divided into an anterior, a middle, and a posterior group. They receive 
vessels from the Diaphragm and liver and send vessels to the internal mammary 
and posterior mediastinal glands. The lymph-vessels of the Diaphragm take 
origin from a capillary network contained in the spaces between the muscular 
and tendinous fasciculi of the Diaphragm. Numerous lymph-vessels descend 
until they reach the subperitoneal tissues and then ascend. Others immediately 
ascend to beneath the pleura. The collecting trunks are all on the convex surface 
of the Diaphragm. The lymphatic vessels of the Diaphragm anastomose with 
the lymphatic vessels of the pleura and the peritoneum. This subperitoneal 
network is so extensive that absorption in this region is extremely rapid. 
Hence, after an abdominal operation, if salt solution has been left in the ab- 
domen, it will be very rapidly absorbed if the foot of the bed is elevated. 
Influenced by the knowledge that the pelvic peritoneum absorbs comparatively 
slowly and the peritoneum in the upper abdomen very rapidly, and that septic 
processes in the upper abdomen are more rapidly fatal than septic processes in 
the pelvis, Fowler was led to recommend the elevation of the head of the bed 
after operations for abdominal infections. This posture causes poisonous fluids 
to gravitate away from the Diaphragm. THE LYMPHATIC GLANDS OF THE THORACIC WALL 
811 
The Visceral Lymphatics.-The visceral lymphatics include the anterior medi- 
astinal glands, the posterior mediastinal glands, and the peritracheo-bronchial glands. 
The Anterior Mediastinal Glands (Jymphoglandulae mediastinales anterior es).-The 
anterior mediastinal glands are in the upper portion of the anterior mediastinum, 
a group of six or seven glands lying above and upon the front of the transverse 
DEEP CERVICAL 
RIGHT LYMPHATIC 
DUCT' 
SCALENUS ANTICUS 
MUSCLE 
-THORACIC DUCT 
MEDIASTINAL 
GLANDS AND 
VESSELS 
INTERCOSTAL 
GLANDS AND 
VESSELS 
RECEPTACULUM 
CHYLI 
COMMON INTES 
TINAL TRUNK 
PRE-AORTIC 
-GLANDS AND 
VESSELS 
LUMBAR 
COMMON INTES- 
TINAL TRUNK 
SACRAL- 
-INTERNAL ILIAC 
EXTERNAL ILIAC 
Fig. 511.-Deep lymphatic glands and vessels of the thorax and abdomen (diagrammatic). Afferent vessels are 
represented by continuous lines, and efferent and interglandular vessels by dotted lines. (Cunningham.) 
portion of the arch of the aorta and sending glandular chains toward the neck. 
On the right side these glands are found between the innominate artery and vein 
and in front of the vein. On the left side they are in front of and behind the left 
common carotid and left subclavian arteries. They receive lymph from the heart, 
pericardium, thymus gland, and anterior mediastinum. 812 
THE LYMPHATIC SYSTEM 
The Posterior Mediastinal Glands (lymphoglandulae mediastinales posteriores) 
(Fig. 511).-The posterior mediastinal glands are behind the pericardium and 
in front of the oesophagus. Occasionally one or two are placed back of the 
oesophagus. They receive vessels from the intercostal glands, aortic glands, 
deep cervical glands, and pleura, and send vessels to the thoracic duct. 
The Peritracheo-bronchial Glands.-The peritracheo-bronchial glands are divided 
by Barety into four groups. One group is in the angle formed by the junction 
of the trachea and right bronchus. Another group is in a corresponding situation 
on the left side. Another group is below the tracheal bifurcation. The glands of 
the fourth group are about the points of division of the larger bronchi. The 
peritracheo-bronchial glands receive lymph-vessels from the lung, heart, peri- 
cardium, oesophagus, trachea, and thymus. 
In infancy these glands present the same appearance as the lymphatic glands in other situa- 
tions. In early adult life they assume a brownish tinge, and in old age become deep black, 
because they arrest particles of carbon brought from the bronchi. This change is known as 
anthracosis, and the darkened glands are usually sclerotic. In fact, in old age these glands often 
lose all lymphatic characters and become fibrous masses. These glands enlarge from infection, 
and when very large may compress the bronchi, the pulmonary artery, etc. They are often the seat 
of tuberculous deposits. 
The Lymphatic Vessels of the Thoracic Wall.-The lymphatic vessels of the 
thoracic wall include the deep lymphatic vessels, intercostal and internal mammary, 
which have been described, the cutaneous lymphatics, and the lymphatics of the 
mammary gland. 
The Cutaneous Lymphatics (Fig. 497).-The area drained by these lymphatics 
is very extensive. It is divided by Poirier, Cundo, and Delamare into three regions. 
The anterior region extends from over the middle of the sternum to the anterior axil- 
lary line. The trunks pass to the axilla and terminate in the thoracic chain of the 
axillary glands. From this anterior region some accessory trunks pass above the 
clavicle and reach the supra-clavicular glands, and trunks may arise to one side 
of the mid-sternal line and pass to the opposite axilla. From the lateral region the 
trunks ascend to the thoracic chain of axillary glands. This region is between 
the anterior and posterior axillary lines. The posterior region is back of the 
posterior axillary line, and includes the thorax to the mid-line, and the posterior 
portion of the root of the neck. The trunks from the posterior area empty into 
the scapular group of axillary glands. 
Lymphatics of the Mammary Gland (Figs. 496 and 512).-There are two sets 
of lymphatics in this gland, the cutaneous or superficial and the glandular or deep. 
The Peripheral Cutaneous Lymphatics of the Mammary Gland.-The peripheral 
cutaneous lymphatics do not arise from the nipple. Their collecting trunks are 
arranged as are other collecting trunks of the anterior portion of the thorax, and 
end in the thoracic group of axillary glands of the same side. Trunks arising from 
the sternal margin of the skin of the breast may run to the glands of the opposite 
axilla. 
The Central Deep Lymphatics of the Mammary Gland.-The central lymphatics 
form a very extensive network in the nipple and areola, and from this network 
numerous vessels pass into a plexus beneath the areola, Sappey's subareolar plexus; 
most of the trunks coming from the gland also enter the subareolar plexus. 
The Glandular Lymphatics of the Mammary Gland.-The glandular lymphatics 
arise from spaces about the lobules and from networks about the milk-ducts. XX e 
can distinguish a chief lymphatic channel and three accessory channels. 
The chief lymphatic channel takes origin from collecting trunks which begin 
in the spaces about the lobules and in the lymph-capillaries about the milk-ducts. 
These collectors pass toward the nipple and terminate in the subareolar plexus, 
which plexus also receives the vessels from the areola and nipple. Two large THE LYMPHATIC GLANDS OF THE THORACIC WALL 
813 
trunks take origin from the subareolar plexus: one from its inner side, the other 
from its outer side. "The internal trunk runs at first downward and then out- 
ward, turning round the inferior border of the subareolar plexus. It is thus 
directed toward the axilla and runs in the subcutaneous cellular tissue, along the 
lower border of the Pectoralis major, which it crosses at the level of the third 
rib to reach the base of the axilla. This collecting trunk constantly receives as 
afferents one or two fair-sized trunks coming directly from the inferior portion of 
the mammary gland. The external trunk, which is usually smaller than the pre- 
ceding, runs directly outward toward the axilla. Before it reaches the latter it 
is augmented by a vessel coming from the superior part of the gland. At the base 
of the axilla these two collecting trunks perforate the axillary aponeurosis and 
terminate in one or two glands, placed on the inner wall of the axilla on the third 
digitation of the Serratus magnus muscle. These glands (the principal regional 
glands of the breast) may or may not be covered by the lower part of the Pec- 
Fig. 512.-The vessels and lymphatics of the anterior face of the mammary glands. (Sappey.) 
toralis major muscle according to the muscular development of the subject (Sur- 
gius)."1 These glands constitute the supero-internal mass of the anterior axillary 
chain. An interrupting gland is sometimes found in the course of these two 
trunks, the paramammary gland. 
The Accessory Channels from the Mammary Gland.-The accessory channels from 
the mammary gland, according to Poirier, Cun^o, and Delamare, are three. They 
call one the accessory axillary channel. It is not constant, and there may be inter- 
rupting glands on its collectors. Its collectors come off from the inferior portion 
of the mammary gland and pass directly to the axillary glands. Another channel 
is the subclavian channel. Neither is it constant. It comes off from the posterior 
surface of the mammary gland, pierces the great Pectoral muscle, and ascends 
between the greater and lesser Pectorals to reach the subclavian glands. There 
1 The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. THE LYMPHATIC SYSTEM 
814 
are usually interrupting glands along this channel, the retro-pectoral glands. The 
subclavian channel runs along the superior thoracic artery. They call the third 
accessory channel the internal mammary channel. The collecting trunks arise 
from the inner portion of the mammary gland and pass along the vessels sent off 
from the internal mammary artery to the gland. They pierce the Pectoral and 
Intercostal muscles and reach the internal mammary glands. This channel is 
constant and along it there may be interrupting glands. 
Lymphatics of the Great Pectoral Muscle.-The lymphatics of the great Pectoral 
muscle end in the subclavian glands, the thoracic group of axillary glands, and 
the internal mammary glands. 
Surgical Anatomy.-A knowledge of the lymphatics of the breast and of the glands into which 
the lymphatics drain is of the first importance to a surgeon. Certain surgical deductions from 
the anatomy of this region are perfectly obvious-viz.: 1. If the skin of the mammary gland is 
involved in carcinoma, the thoracic group of axillary glands of the same side is involved. If the 
skin over the sternal margin of the gland is involved, the glands of the opposite axilla may be can- 
cerous, as from this point lymph-vessels rise and pass across the mid-line. If the skin of the 
sternal margin is involved the prognosis is worse than if it is free, the opposite axilla may be 
cancerous, and the opposite breast may become diseased. 2. When lymphatic ducts become 
blocked by cancer cells the lymph backs up, flows backward instead of in its proper direc- 
tion, and may cause infecton in the most unsuspected situations. For instance, a block in the 
cutaneous lymphatics of a portion of the breast may lead to infection of the opposite breast and 
axilla, though, of course, it is not so likely to as is cancer of the skin of the sternal margin. By 
regurgitation of lymph the head of the humerus or the retro-sternal structures may become dis- 
eased in mammary cancer. 3. If the nipple or areola is cancerous, the entire gland is sure to be 
diseased, as the lymphatic network of this region empties into the subareolar plexus, and most 
of the trunks coming from the gland also enter this plexus. 4. If the mammary gland is cancer- 
ous, all of the axillary glands are regarded as diseased, as the main lymphatic channel from the 
breast reaches the glands on the inner wall of the axilla upon the third digitation of the Ser- 
ratus magnus. Furthermore, in many cases an accessory lymph-channel comes off from the 
lower portion of the mammary gland and passes directly to the axilla. 5. The subclavian glands 
are to be regarded as diseased, because in a certain proportion of cases (the exact proportion 
being uncertain) an accessory lymph-channel comes off from the posterior surface of the mam- 
mary gland, passes through the great Pectoral muscle and ascends between the greater and 
lesser Pectorals to reach the subclavian glands. 6. The element which greatly interferes with 
the cure of mammary carcinoma is the existence of lymph-channels which arise from the inner 
portion of the mammary gland, pierce the greater Pectoral and Internal intercostal muscles, and 
reach the internal mammary glands. Mediastinal involvement is apt to be earlier in carcinoma 
of the inner portion of the breast than in carcinoma of other portions, and the prognosis is par- 
ticularly bad in cancer of the inner portion of the breast. What is known as the sternal symptom 
of Snow is bulging of the sternum due to involvement of the thymus gland. 7. The sternal 
portion of the great Pectoral and the tissue between it and the lesser Pectoral muscle are to be 
regarded as diseased, because in some cases an accessory lymph-channel from the breast pene- 
trates the greater Pectoral and ascends to the subclavian glands. This trunk has several inter- 
rupting or satellite glands, the retro-pectoral glands, in the tissue back of the great Pectoral 
muscle. 8. When the great Pectoral muscle is diseased, cancer cells soon spread widely through 
the sternal portion of the muscle, and this entire portion of the muscle becomes cancerous. The 
clavicular portion does not suffer early, but escapes until the cancer becomes extensive, as it 
is anatomically distinct from the sternal portion. If the fibres of the great Pectoral are exten- 
sively diseased, the thoracic group of axillary glands, the subclavian glands, and possibly the 
internal mammary glands are involved. 9. The only operation in cancer of the breast which 
offers any real hope of cure is one which is done early and is radical. 10. It must be done 
early, because delay permits involvement of the mediastinum, and if the disease has entered 
the mediastinum operation is hopeless. If the sternum is bulged operation is useless, and 
nothing short of amputation at the shoulder-joint could be of help if the head of the humerus 
is enlarged by the disease. Even this radical procedure is of no avail, because the mediastinum 
is certainly involved if the head of the humerus is diseased. 11. If the lymph-glands above 
the clavicle are extensively diseased operation is useless, as in such cases the mediastinum is 
sure to be involved. 12. A radical operation means the removal of the skin of the breast with 
the nipple and areola, the subcutaneous tissue of this region, the entire breast the sternal 
portion of the great Pectoral with its fascia, the retro-pectoral glands and tissue, all the con- 
tents of the axilla except vessels and nerves, the glands and cellular tissue beneath the anterior 
margin of the Latissimus dorsi, and the subclavian glands. It is probably always wisest to 
open above the clavicle as well as below to facilitate the removal of glands. It is seldom necessary THE LYMPHATIC GLANDS OF THE THORACIC WALL 
815 
to remove the clavicular portion of the greater Pectoral. The lesser Pectoral does not require 
removal, but it should be taken away, because of the added safety and speed thus obtained 
in cleaning the great vessels and because its retention does not improve the functional result. 
The surgeon must remember that the breast is a much larger organ than we used to think, and 
all of its irregular projections and outlying lobules must be removed (p. 793). Formerly, 
surgeons did not completely remove the breast, but only got rid of a large portion of it. 
The Pulmonary Lymphatics.-The pulmonary lymphatics arise from net- 
works between the lobules, around the bronchi and under the mucous membrane. 
The collecting trunks are in two sets, superficial and deep: the former are placed 
beneath the pleura, forming a minute plexus which covers the outer surface of 
the lung; the latter accompany the blood-vessels and run along the bronchi; they 
both terminate at the root of the lungs in the tracheo-bronchial glands. 
The Pleural Lymphatics.-The lymphatics of the pulmonary pleura pass into the 
superficial pulmonary trunks; those from the costal pleura enter the intercostal 
trunks; those from the diaphragmatic pleura enter the diaphragmatic trunks, and 
those from the mediastinal pleura enter the posterior mediastinal glands.1 
The Cardiac Lymphatic Vessels.-The cardiac lymphatic vessels consist of 
two sets, superficial and deep: the former arise in the subpericardial areolar tissue of 
the surface, and the latter in the subendocardial tissue. From the network of deep 
lymphatics trunks pass to the superficial lymphatics. The superficial lymphatics 
follow the course of the coronary vessels. Two trunks are formed: an anterior, 
which lies in the anterior interventricular furrow, and an inferior, which lies in 
the inferior interventricular furrow. These two trunks collect the lymph from the 
ventricles and pass to the base of the heart, where they receive lymph from the 
auricles. The anterior or left trunk ascends between the left auricle and the pul- 
monary artery on the posterior surface of the artery, perforates the pericardium, and 
enters the glands about the tracheal bifurcation. The right, posterior or inferior 
trunk ascends between the aorta and pulmonary artery and terminates in the same 
group of glands as the left trunk. 
The Thymic Lymphatic Vessels.-The thymic lymphatic vessels arise from 
the under surface of the thymus gland, and enter the anterior mediastinal, the 
internal mammary, and the peritracheo-bronchial glands. 
The Lymphatic Vessels of the (Esophagus.-The lymphatics of the thoracic 
oesophagus arise from two networks, one beneath the mucous membrane and one 
beneath the muscular fasciculi. The connecting trunks terminate in the peri- 
oesophageal glands. 
The Lymphatic Vessels of the Thoracic Trachea.-The lymphatics of the 
thoracic trachea take origin from a network in the submucous tissue. From this 
a number of collecting trunks pass through the trachea in the line of junction of 
the cartilaginous with the membranous portion. They terminate the peritracheo- 
bronchial glands. 
The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. THE NERVOUS SYSTEM. 
TPKE nervous system consists of (1) the cerebro-spinal nervous system and (2) 
I the sympathetic nervous system. 
1. The Cerebro-spinal Nervous System is composed of the spinal cord and 
brain and of nerves joined to the brain and cord. The spinal cord and brain 
constitute the cerebro-spinal axis, or, as it is also called, the encephalo-spinal axis, 
the neuraxis, or the central nervous system. The nerves which join the cord and 
which join the brain constitute the peripheral nervous system. The term central 
nervous system is applied to structures contained altogether within the spinal 
and cranial cavities, but this narrow use is not strictly accurate. By far the greater 
part of the central nervous system is contained within those cavities, but any 
centre of energy must be regarded as a portion of the central system, and certain 
ganglia which are centres of energy lie along certain nerves and really belong to 
the central nervous system, though they are discussed with the peripheral nerves. 
The term peripheral nervous system does not mean, as it would seem to, 
structures outside the spinal and cranial cavities. The chief part of the peripheral 
system is outside of the spinal and cerebral cavities, but peripheral nerves 
"sometimes run a considerable distance within these cavities."1 The peripheral 
nervous system is composed of thirty-one pairs of spinal nerves and twelve 
pairs of cranial nerves. Each spinal nerve is joined to the spinal cord by two roots, 
an anterior and a posterior root, and the posterior root at one point has an enlarge- 
ment called a spinal ganglion. The fifth cranial nerve, alone among cranial nerves, 
takes origin by two roots, as does a spinal nerve. Five of the cranial nerves 
possess ganglia similar to the ganglia on the posterior roots of the spinal nerves. 
The cranial nerves which possess ganglia are the trigeminal or fifth, the facial or 
seventh, the auditory or eighth, the glosso-pharyngeal or ninth, and the pneumo- 
gastric or tenth. 
2. The Sympathetic Nervous System consists of a chain of ganglia on either side 
of the vertebral column. The ganglia of each chain are joined by cords of nervous 
matter. The sympathetic system contains, beside the gangliated cords, numerous 
nerve plexuses and ganglia in various regions. The sympathetic nervous system 
is closely connected at many points with the cerebro-spinal nervous system, and 
the two systems in all probability develop from a common origin. 
Structure of the Cerebro-spinal Nervous System.-The spinal cord and 
brain contain gray matter and white matter. The gray matter is vascular and is 
composed chiefly of nerve-cells: the white matter is less vascular and is composed 
chiefly of nerve-fibres. Until recently it was the custom to regard nerve-cells and 
nerve-fibres as definitely distinct elements, but we now know that nerve-fibres are 
processes of nerve-cells. One process, several processes, or many processes come 
off from nerve-cells. If there is but one process from a cell, that process becomes 
Deiters' process, the axis-cylinder or axone of a nerve-fibre. If more than one 
process comes off from a cell, one of the processes becomes an axone, and the 
other processes are known as protoplasmic or dendritic processes, or, as His named 
1 The Nervous System and its Diseases. By Charles K- Mills. 
817 818 
THE NERVOUS SYSTEM 
them, dendrites. There are no nerve-fibres unconnected with cells. The nerve- 
cell, with its axone and its dendrites, constitutes what is called a nerve-unit or 
neurone. The nervous system is said to be composed of aggregations of multitudes 
of neurones. The term neurone was devised by Waldeyer in 1891. 
Gray, vesicular, or cineritious substance is of a dark, reddish-gray color and of a 
soft consistence. It is found in the spinal cord, brain, and various ganglia, in 
some of the nerves of special sense, and in gangliform enlargements in the course 
of certain spinal nerves. It is composed of nerve-cells and contains blood-vessels, 
both the cells and vessels being embedded in a ground substance named by 
Virchow the neuroglia. The nerve-fibres and the vessels in the white substance 
are also embedded in neuroglia. Neuroglia consists of fibres and neuroglia cells. 
Some of the cells are stellate in shape and their fine processes become neuroglia- 
fibres, which extend radially and unbranched (Fig. 513 B) among the nerve-cells 
and fibres, which they aid in supporting. Other cells give off fibres, which branch 
repeatedly (Fig. 513 A). 
A 
B 
Fig. 513.-Neuroglia-cells of brain shown by Golgi's method. A. Cell with branched processes. B. Spider- 
cell with unbranched processes. (After Andriezen.) (Copied from Schafer's Essentials of Histology.) 
In addition to these fibres there are others which do not appear to be connected 
with the neuroglia-cells. They start from the lining ependymal cells, that is, the 
epithelial cells lining the ventricles of the brain and central canal of the spinal 
cord, and pass through the nervous tissue, branching repeatedly, to terminate in 
slight enlargements on the pia mater. Thus, neuroglia is evidently a connective 
tissue in function, though it is not in development; it is epiblastic in origin, whereas 
all true connective tissues are mesoblastic. 
The white or fibrous tissue is composed of nerve-fibres, which, with blood- 
vessels, are embedded in neuroglia. 
Nerve-cells or the Cell-bodies of the Neurones (Figs. 514, 515, 516. 517, 518, and 
519).-Nerve-cells constitute the essential element of nervous tissue. They are the 
originators of nervous impulses and impressions. All nervous conduction is from 
nerve-cell to nerve-cell by contact (Mills), and the transmission of an impulse 
from one nerve-cell to another may be over a long distance. The nerve-cells of 
the brain and cord differ in origin, development, and connections from the nerve- 
cells of the spinal ganglia. They vary greatly in shape and size (Fig. 515). 
Some are so small that they become visible only under a microscope of high STRUCTURE OF THE CEREBRO-SPINAL NERVOUS SYSTEM 
819 
power; some "almost come within the range of unaided vision.''1 The largest 
cells are found in the anterior cornua of the spinal cord, in the vesicular columns 
of Clarke, in the large pyramidal cell-layer of the cerebral cortex, and the Purkin- 
jean cell-layer of the cerebellum. The smallest cells are in the olfactory bulbs, 
in the substantia gelatinosa Rolandi of the cord, and in the granular cortical 
layers of the cerebrum and cerebellum. 
Fig. 514.-Nerve-cells from the Gasserian 
ganglion of the human subject, a. A globu- 
lar one with defined border, b. Its nucleus. 
c. Its nucleolus, d. Caudate cell. e. Elon- 
gated cell with two groups of pigment-par- 
ticles. f. Cell surrounded by its sheath or 
capsule of nucleated particles, q. The same, 
the sheath only being in focus. Magnified 300 
diameters. 
Arone. 
Fig. 515.-Nerve-cells from the inner part of the 
gray matter of the convolutions of the human brain. 
Nerve-cells: a. Larger, b. Smaller, c. Nerve-fibre 
with axis-cylinder. Magnified 350 times. 
.Sheath of 
cell body. 
'Nucleus. 
Cell protoplasm. 
Axone. 
-Myelin sheath. 
Axone. 
Fig. 517.-Motor nerve-cell from ventral horn 
of spinal cord of rabbit. The angular and spindle- 
shaped Nissl bodies are well shown. (After 
Nissl.) 
Fig. 516.-Bipolar nerve-cells from the spinal gan- 
glion of the pike. (After Kolliker.) 
The Body of the nerve-cell may possess a limiting membrane, as is seen in the 
cells of the spinal ganglia (Fig. 516) and sympathetic ganglia, and some of the 
cells of the Gasserian ganglion (Figs. 514, f and 7), but may be devoid of any 
limiting membrane, as is seen in the motor cells of the anterior cornua of the cord 
(Fig. 517). All cell-bodies, like all cell-processes, show intracellular fibrillation, 
and the fibrils of the cell-body are continuous with those of the axone and run in 
1 Text-book of Anatomy. By Prof. D. J. Cunningham. THE NERVOUS SYSTEM 
820 
various directions, rhe cell-body is composed of protoplasm, which contains, 
besides fibrils, many fine spindle-shaped granules. The granules stain deeply 
and are called chromatophile granules, Nissl's bodies, or trigoid bodies (Fig. 517). 
They are probably nucleo-albumins (Held). Most nerve-cells, certainly most large 
nerve-cells, possess considerable pigmented material, a nucleus, and a nucleolus. 
The nucleus (Fig. 514 b) is, as a rule, a large, well-defined, round, vesicular 
body, often presenting an intranuclear network. It contains a nucleolus (Fig. 
514 c), which is peculiarly clear and bril- 
liant. Pigment granules (Fig. 514 e), 
when present, lie by the side of the nu- 
cleus. Masses of pigment are present 
in the cells of the substantia nigra and 
locus caeruleus. 
Nerve-cells are divided for purposes 
of study into three groups, according to 
the number of their processes. 
1. Unipolar Cells.-The single process 
of such a cell, after a short course, divides 
in a T-shaped manner. Unipolar cells 
are found in the spinal ganglia of the 
adult and among the olfactory cells of 
mammals. 
Fig. 518.-Pyramidal cell from the cerebral cortex 
of a mouse. (After Ramon y Cajal.) 
Fig. 519.-Cell of Purkinje from the cerebellum of 
a cat. (After Hamon y Cajal.) 
2. Bipolar cells (Fig. 516) are found in spinal ganglion-cells when the cells are in 
an embryonic condition. They are best demonstrated in the sympathetic ganglion- 
cells of a frog. Sometimes the processes come off from opposite poles of the cell, 
and the cell then assumes a spindle shape; in others they both emerge at the same 
point. In some cases where two fibres are apparently connected with a cell, one 
of the fibres is really derived from an adjoining nerve-cell and is passing to end 
in a ramification around the ganglion-cell, or, again, it may be coiled spirally 
around the nerve-process which is issuing from the cell. STRUCTURE OF THE CEREBRO-SPINAL NERVOUS SYSTEM 
821 
3. Multipolar cells (Fig. 517) are caudate or stellate in shape, and are character- 
ized by their large size and by the tail-like processes which issue from them. The 
processes are of two kinds: one of them is the axis-cylinder or axone; the others 
are the protoplasmic processes or dendrites. 
The Axone (Figs. 515, 516. 517, 518, and 519).-The axone emerges from the 
nerve-cell by a slender stalk; it is smooth and free from Nissl's bodies; it main- 
tains a uniform diameter for a considerable distance; it does not, as a rule, divide 
into branches, although it may possess collaterals, and it becomes the axis-cylinder 
of a nerve-fibre. Cerebro-spinal axones, as a rule, are medullated, except near 
their terminations. Sympathetic axones are non-medullated. Axones may be 
extremely short or may be several feet in length. The fibres of the pyramidal 
tract are axones of great length. Some short axones divide at their terminations 
into many branches. Short axones are called dendraxones, and the cells with den- 
draxones are called the second type of Golgi cells. An axone may remain throughout 
its entire course in the brain or cord or may enter into a spinal or cerebral nerve. 
Most cells possess but one axone, and such a neurone is called monoaxonic. A cell 
may possess two axones, the neurone being called diaxonic, or several axones, the 
neurone being called polyaxonic. The collaterals are branches given off from the 
neurone at right angles to it. Some axones have a number of collaterals; others 
do not have any. They are present everywhere in the central nervous system 
(Cajal, Kolliker). Some collaterals are medullated; others are not. They 
approach the dendrites of the nerve-cells of the neurones. Each axone and col- 
lateral ends in a button-like termination or end-tuft, or in a free arborization, the 
end-brush. If the termination is within the brain or cord, it may wrap around 
nerve-cells or arborize about dendrites. If the axone emerges from the cerebro- 
spinal axis, it terminates about muscle-cell or some other structure. The termi- 
nation of the axone or the collateral is never continued into the structure about 
which it lies. It may surround that tissue; it may touch it; it may lie close against 
it, but the termination is free, and the relation is simply one of contact and not of 
continuity. 
The Dendrites.-The dendrites are protoplasmic processes resembling in struc- 
ture and staining reactions the protoplasm of the body of the cell. Each emerges 
by a thick base (gemmule), and divides into many fine branches, with free ends. 
They are not straight, are not smooth, and do not maintain the same diameter for 
a considerable distance as does the axis-cylinder. A dendrite may branch at 
any distance from the body of the cell, and the branches do not join. The den- 
drites from a single cell vary greatly in number, thickness, and length. Some 
cells are devoid of dendrites; some give off a few; some give off many. As a rule, 
they are non-medullated. 
The Theory of Neurones.-This theory maintains that the nervous system is com- 
posed of a multitude of units called neurones. Each neurone consists of a cell and 
processes. The neurones in aggregation form cell groups and fibre systems. The 
connection of nerve-cells with other nerve-cells is not by continuity of structure. 
It is by contact and not by actual junction; it is physiological and not anatomical. 
"When fully developed in man, perhaps a very small number of neurones are 
united together by concrescence or protoplasmic bridges, but their predominant 
relation is certainly that of contact or synapsis."1 Process comes in contact with 
process, or process with cell. The terminal tufts of the axone of a cortical motor- 
cell surround a cell in the anterior horn of the spinal cord, and this spinal cell 
sends out an axone, the termination of which reaches a muscle. Doubt has of 
late arisen as to the neurone theory, because of the investigations of Apathy and 
others. Apathy claims that ganglion cells join directly and that the ultimate 
1 Anatomy of the Brain and Nervous System. By Harris E. Santee. 822 
THE NERVOUS SYSTEM 
elements of the nervous system are neurofibrils, which pass from cell to cell. 
However, as stated by Szymonowicz,1 Apathy's observations, even if correct, do 
not disprove the neurone theory, but indicate that the nervous units or neurones 
are occasionally connected by neurofibrils. 
Nerve-fibres.-Nerve-fibres serve to conduct nervous impulses and bring nerve- 
cells into relation with each other and into relation with other structures. Nerves 
are composed of numbers of nerve-fibres bound into bundles. There are two sorts 
of fibres: medullated or white and non-medullated or gray. 
The Medullated fibres form the white part of the brain and spinal cord, and 
also the greater part of the cerebro-spinal nerves, and gives to these structures 
their opaque, white aspect. When perfectly fresh they appear to be homoge- 
neous; but soon after removal from the body they present, when examined by 
transmitted light, a double outline or contour, as if consisting of two parts (Figs. 
520 and 521). The central portion is named the axis-cylinder of Purkinje (Fig. 
521); around this is a sort of sheath of fatty material, staining black with osmic 
Fibrils of axis- 
cylinder. 
Neurilemma. 
Segment of 
Lantermann. 
White substance 
of Schwann 
stained black 
by osmic acid. 
Fig. 520.-White or medullated nerve- 
fibres showing the sinuous outline and 
double contours. (After Schafer.) 
Fig. 521.-Longitudinal section through a nerve-fibre 
from the sciatic nerve of a frog. X 830. (After Bohm and 
Davidoff.) 
acid, named the white substance of Schwann (Fig. 521), which gives to the fibre 
its double contour, and the whole is enclosed in a delicate membrane, the neuri- 
lemma, primitive sheath, or nucleated sheath of Schwann (Fig. 521). 
The axis-cylinder is the essential part of the nerve-fibre, and is always present; 
the other parts, the medullary sheath and the neurilemma, being occasionally 
absent, especially at the origin and termination of the nerve-fibre. It undergoes 
no interruption from its origin in the nerve-centre to its peripheral termination, 
and must be regarded as a direct prolongation of a nerve-cell. It constitutes 
about one-half or one-third of the nerve-tube, the whole substance being greater 
in proportion in the nerves than in the central organs. It is perfectly transparent, 
and is therefore indistinguishable in a perfectly fresh and natural state of the 
nerve. It is made up of exceedingly fine fibrils, which stain darkly with gold 
chloride (Fig. 521). At its termination the axis-cylinder of a nerve-fibre may be 
seen to break up into fibrilhe, confirming the accepted view of its structure. These 
fibrilhe have been termed the primitive fibrillae of Schultze. The axis-cylinder is said 
1 Text-book of Histology and Microscopic Anatomy. By Dr. Ladislaus Szymonowicz. 1 ranslated and edited 
by John Bruce MacCallum, M.D. DEVELOPMENT OF NERVE-CELLS AND FIBRES 
823 
by some to be enveloped in a special, reticular sheath, which separates it from the 
white matter of Schwann, and is composed of a substance called neurokeratin. 
The more common opinion is that this network or reticulum is contained in the 
white matter of Schwann, and by some it is believed to be produced by the action 
of the reagents employed to demonstrate it. The medullary sheath or white sub- 
stance of Schwann (Fig. 521) is regarded as being fatty matter in a fluid state, which 
insulates and protects the essential part of the nerve-the axis-cylinder. The white 
matter varies in thickness to a very considerable extent, in some nerve-fibres forming 
a layer of extreme thinness, so as to be scarcely distinguishable; in others forming 
about one-half of the nerve-tube. The size of the nerve-fibres, which varies from 
to T2V7 °f an in(?h, depends mainly upon the amount of the white substance, 
though the axis-cylinder also varies in size within certain limits. The white sub- 
stance of Schwann does not always form a continuous sheath for the axis-cylinder, 
but undergoes interruptions in its continuity at regular intervals, giving to the 
fibre the appearance of constriction at these points. These constrictions were first 
described by Ranvier, and are known as the nodes of Ranvier (Fig. 522). The portion 
Fig. 522.-A node of Ranvier of a medullated nerve-fibre, viewed from above, magnified about 750 diameters. 
The medullary sheath is discontinuous at the node, whereas the axis-cylinder passes from one segment into the 
other. At the node the sheath of Schwann appears thickened. (Klein and Noble Smith.) 
of nerve-fibre between two nodes is called an intemodal segment. The neurilemma 
or primitive sheath is not interrupted at the nodes, but passes over them as a con- 
tinuous membrane. In addition to these interruptions oblique clefts may be seen 
in the medullary sheath, subdividing it into irregular portions, which are termed 
medullary segments or segments of Lantermann (Fig. 521). There is reason to 
believe that these clefts are artificially produced in the preparation of the speci- 
mens. Medullated nerve-fibres, when examined, frequently present a beaded or 
varicose appearance; this is due to manipulation and pressure causing the oily 
matter to collect into drops, and in consequence of the extreme delicacy of the 
primitive sheath, even slight pressure will cause the transudation of the fatty 
matter, which collects as drops of oil outside the membrane. This is, of course, 
promoted by the action of certain reagents. 
The neurilemma or primitive sheath, sometimes called the tubular membrane or 
sheath of Schwann (Fig. 521), presents the appearance of a delicate, structureless 
membrane. Here and there beneath it, and situated in depressions in the white 
matter of Schwann, are nuclei surrounded by a small amount of protoplasm. 
The nuclei are oval and somewhat flattened, and bear a definite relation to the 
nodes of Ranvier; one nucleus generally lying in the centre of each internode. 
The primitive sheath is not present in all medullated nerve-fibres, being absent 
in those fibres which are found in the brain and spinal cord. 
Non-medullated Fibres.-Most of the nerves of the sympathetic system, and 
some of the cerebro-spinal, consist of another variety of nervous fibres, which are 
called the gray or gelatinous nerve-fibres-fibres of Remak (Fig. 523). These con- 
sist of a central core or axis-cylinder enclosed in a nucleated sheath, which tends 
to split into fibrillae, and is probably of the nature of neurokeratin. In external 
appearance the gelatinous nerves are semi-transparent and gray or yellowish- 
gray. The individual fibres vary in size, generally averaging about half the size 
of the medullated fibres. 
Development of Nerve-cells and Fibres.-The nerve-cells are developed 
from certain of the cells which line the neural canal and form the neural crest of the 
embryo. Some of these cells assume a rounded form and are termed neuroblasts, 824 
THE NERVOUS SYSTEM 
and from each neuroblast there grows out a process, the axis-cylinder process or 
axone, and subsequently the branching processes or dendrons. The axis-cylin- 
ders, at first naked, acquire their medullary sheaths, possibly by some metamor- 
phosis of their outer layer. The neurilemma is thought to be derived from 
mesoblastic cells which become flattened and wrapped around the fibre, the 
cement-substance at their opposed ends forming the material which stains with 
silver nitrate at the nodes of Ranvier. Nerve-cells in the sympathetic and periph- 
eral ganglia take their origin from small collections of neuroblasts, which are split 
off from the rudimentary spinal ganglia. Cells which are, originally, similar to 
neuroblasts seem to give rise to neuroglia-cells, numerous processes sprouting from 
the cell to form the neuroglial fibres. 
Chemical Composition.-The amount of water in nervous tissue varies with 
the situation. Thus in the gray matter of the cerebrum it constitutes about 83 per 
cent., in the white matter from the 
same region about 70 per cent., while 
in the peripheral nerves, such as the 
sciatic, it may fall to 60 per cent. 
The solids consist of proteids (in 
the gray matter proteids constitute 
half the total solids), neuro keratin, 
nuclein, protagon, lecithin, cerebrc- 
Fig. 524.-Transverse section through a microscopic 
nerve, representing a compound nerve-bundle, sur- 
rounded by perineurium. Magnified 120 diameters. 
The medullated fibres are seen as circles with a cen- 
tral dot-viz., medullary sheath and axis-cylinder-in 
transverse section. They are embedded in endoneurium, 
containing numerous nuclei, which belong to the con- 
nective-tissue cells of the latter, p. Perineurium, con- 
sisting of laminee of fibrous connective tissues, alter- 
nating with flattened nucleated connective-tissue cells. 
I. Lymph-space between epineurium and surface of 
nerve-bundle. (Klein and Noble Smith.) 
Fig. 523.-A small nervous branch from the 
sympathetic of a mammal, a. Two medullated 
nerve-fibres among a number of gray nerve-fibres, b. 
sides, cholesterin, nitrogenous extractives, and salts, with some gelatin and fat 
from the adherent connective tissue. 
The nervous structures are divided, as before mentioned, into two great systems 
-viz., the cerebro-spinal, comprising the spinal cord and brain, the nerves con- 
nected with these structures and the ganglia situated on them; and the sympa- 
thetic, consisting of a double chain of ganglia and the nerves connected with them. 
All these structures require separate consideration; they are composed of the two 
kinds of nervous tissue above described, intermingled in various proportions, and 
having, in some parts, a very intricate arrangement. 
The nerves are round or flattened cords, formed of a number of nerve-fibres. 
They are connected at one end with the cerebro-spinal centre or with the ganglia, 
and are distributed at the other end to the various textures of the body; they 
are subdivided into two great classes-the cerebro-spinal, which proceed from the 
cerebro-spinal axis, and the sympathetic or ganglionic nerves, which proceed from 
the ganglia of the sympathetic. The cerebro-spinal nerves consist of numerous CHEMICAL COMPOSITION 
825 
nerve-fibres collected together and enclosed in a membranous sheath (Fig. 524). 
A small bundle of primitive fibres,enclosed in a tubular sheath, is called a funiculus: 
if the nerve is of small size, it may consist only of a single funiculus; but if large, 
the funiculi are collected together into larger bundles or fasciculi, which are bound 
together in a common membranous investment. 
In structure the common membranous investment, or sheath of the whole nerve, 
which is called the epineurium, as well as the septa given off from it, and which 
separate the fasciculi, consists of connective tissue, composed of white and yellow 
elastic fibres, the latter existing in great abundance. The tubular sheath of the 
funiculi, called the perineurium,consists of a fine, smooth, transparent membrane, 
which may be easily separated, in the form of a tube, from the fibres it encloses; 
in structure it consists of connective tissue, which has a distinctly lamellar arrange- 
ment, being composed of several lamellae, separated from each other by spaces 
containing lymph. The nerve-fibres are held together and supported within the 
funiculus by delicate connective tissue called the endoneurium. It is continuous 
with septa which pass inward from the innermost layer of the perineurium, and 
consists of a ground-substance in which are embedded fine bundles of fibrous 
connective tissue which run for the most part longitudinally. It serves to support 
the capillary vessels, which are arranged so as to form a network with elongated 
meshes. The cerebro-spinal nerves consist almost exclusively of medullated nerve- 
fibres the non-medullated existing in very small proportions. 
The blood-vessels supplying a nerve terminate in a minute capillary plexus, 
the vessels composing which pierce the perineurium and run, for the most part, 
parallel with the fibres; they are connected together by short, transverse vessels, 
forming narrow, oblong meshes, similar to the capillary system of muscle. Fine 
non-medullated nerve-fibres accompany these capillary vessels, the vaso-motor 
fibres, and break up into elementary fibrils, which form a network around the 
vessel. Horsley has also demonstrated certain medullated fibres as running in the 
epineurium and terminating in small spheroidal tactile corpuscles or end-bulbs of 
Krause. These nerve-fibres, which Marshall believes to be sensory, and which he 
has termed nervi nervorum, are considered by him to have an important bearing 
upon certain neuralgic pains. 
Nerves, in their course, subdivide into branches, and these frequently commu- 
nicate with branches of a neighboring nerve. 
The nerve-fibres, as far as is at present known, do not coalesce, but pursue an 
uninterrupted course from the centre to the periphery. In separating a nerve, 
however, into its component funiculi, it may be seen that they do not pursue a 
perfectly insulated course, but occasionally join at a very acute angle with other 
funiculi proceeding in the same direction; from this, branches are given off, to 
join again in like manner with other funiculi. It must be distinctly understood, 
however, that in these communications the nerve-fibres do not coalesce, but merely 
pass into the sheath of the adjacent nerve, become intermixed with its nerve-fibres, 
and again pass on, to become blended with the nerve-fibres in some adjoining 
funiculus. 
The communications which take place between two or more nerves form what 
is called a plexus. Sometimes a plexus is formed by the primary branches of the 
trunks of the nerves-as the cervical, brachial, lumbar, and sacral plexuses-and 
occasionally by the terminal funiculi, as in the plexuses formed at the periphery 
of the body. In the formation of a plexus the component nerves divide, then 
join, and again subdivide in such a complex manner that the individual funiculi 
become interlaced most intricately; so that each branch leaving a plexus may 
contain filaments from each of the primary nervous trunks which form it. In the 
formation also of smaller plexuses at the periphery of the body there is a free 
interchange of the funiculi and primitive fibres. In each case, however, the 826 
THE NERVOUS SYSTEM 
individual filaments remain separate and distinct, and do not inosculate with one 
another. 
It is probable that through this interchange of fibres the different branches 
passing off from a plexus have a more extensive connection with the spinal cord 
than if they each had proceeded to be distributed without such connection with 
other nerves. Consec|iiently the parts supplied by these nerves have more extended 
relations with the nervous centres; by this means, also, groups of muscles may be 
associated for combined action. 
The sympathetic nerves are constructed in the same manner as the cerebro- 
spinal nerves, but consist mainly of non-medullated fibres, collected into funiculi, 
and enclosed in a sheath of connective tissue. There is, however, in these nerves a 
certain admixture of medullated fibres (Fig. 523), and the amount varies in different 
nerves, and may be known by their color. Those branches of the sympathetic 
which present a well-marked gray color are composed more especially of gelatinous 
nerve-fibres, intermixed with a few medullated fibres; while those of a white 
color contain more of the latter fibres and a few of the former. Occasionally, the 
gray and white cords run together in a single nerve, without any intermixture, as 
in the branches of communication between the sympathetic ganglia and the spinal 
nerves, or in the communicating cords between the ganglia. 
The nerve-fibres, both of the cerebro-spinal and sympathetic system, convey 
impressions of a twofold kind. The sensory nerves, called also centripetal or 
afferent nerves, transmit to the nervous centres impressions made upon the periph- 
eral extremities of the nerves, and in this way the mind, through the medium 
of the brain, becomes conscious of external objects. The motor nerves, called 
also centrifugal or efferent nerves, transmit impressions from the nervous centres 
to the parts to which the nerves are distributed, these impressions either exciting 
muscular contraction, or influencing the processes of nutrition, growth, and 
secretion. 
Origin ^nd Termination of Nerves.-By the expression "the termination of 
nerve-fibres" is signified their connection with the nerve-centres, and with the 
parts they supply. The former are sometimes called their origin, or central 
termination; the latter their peripheral termination. The origin in some cases is 
single-that is to say, the whole nerve emerges from the nervous centre by a single 
root; in other instances the nerve arises by two or more roots, which come off 
from different parts of the nerve-centre, sometimes widely apart from each other, 
and it often happens, when a nerve arises in this way by two roots, that the 
functions of these two roots are different; as, for example, in the spinal nerves, 
each of which arises by two roots, the anterior of which is motor and the posterior 
sensory. The point where the nerve-root or roots emerge from the nervous centre 
is named the superficial or apparent origin, but the fibres of which the nerve con- 
sists can be traced for a certain distance into the nervous centre to some portion 
of the gray substance, which constitutes the deep or real origin of the nerve. 
'The manner in which these fibres arise at their deep origin varies with their 
functions. The centrifugal or efferent nerve-fibres originate in the nerve-cells of 
the gray substance, the axis-cylinder processes of these cells being prolonged to 
form the fibres. In the case of the centripetal or afferent nerves the fibres grow 
inward either from nerve-cells in the organs of special sense (e. g., the retina) 
or from nerve-cells in the ganglia. Having entered the nerve-centre, they branch 
and send their ultimate twigs among the cells, without, however, uniting with 
them. 
Peripheral Terminations of Nerves.-Nerve-fibres terminate peripherally in 
various ways, and these may be conveniently studied in the sensory and motor 
nerves, respectively. Sensory nerves would appear to terminate either in minute 
primitive fibrilla? or networks of fibrillae; or else in special terminal organs, which ORIGIN AND TERMINATION OF NERVES 
827 
have been termed peripheral end-organs, and of which there are several principal 
varieties-viz., the end-bulbs of Krause, the tactile corpuscles of Wagner, the Pacinian 
corpuscles, and the neuro-tendinous and neuro-muscular spindles. 
Termination in Fibrillae.-When a medullated nerve-fibre approaches its termi- 
nation, the white matter of Schwann suddenly disappears, leaving only the axis- 
cylinder, surrounded by the neurilemma, and forming a non-medullated fibre. 
This, after a time, loses its neurilemma, and consists only of an axis-cylinder, 
which can be seen, in preparations stained with chloride of gold, to be made up 
of fine varicose fibrils. Finally, the axis-cylinder breaks up into its constituent 
primitive nerve-fibrilla?, which often present regular varicosities and anastomose 
with one another, thus forming a network. This network passes between the 
elements of the tissue to which the nerves are distributed, which is always epithe- 
lial, the nerve-fibrils lying in the interstitial substance between the epithelial cells, 
and there terminating, though some observers maintain that the actual termina- 
tions are within the cells. In this way nerve-fibres have been found to terminate 
in the epithelium of the skin and mucous membranes, and in the anterior epithe- 
lium of the cornea. 
Fig. 526. -Tactile papilla of the hand treated with acetic 
acid. Magnified 350 times. A. Side view of a papilla of the 
hand. a. Cortical layer, b. Tactile corpuscle, with trans- 
verse nuclei, c. Small nerve of the papilla, with neuri- 
lemma. d. Its two nervous fibres running with spiral 
coils around the tactile corpuscle, e. Apparent termina- 
tion of one of these fibres. B. A tactile papilla seen from 
above, so as to show its transverse section, a. Cortical 
layer b. Nerve-fibre, c. Outer layer of the tactile body, 
with nuclei, d. Clear interior substance. 
Fig. 525.-End-bulb of Krause, a. Medul- 
lated nerve-fibre. b. Capsule of corpuscle. 
(From Klein's Elements of Histology.) 
The End-bulbs of Krause (Fig. 525) are minute cylindrical or oval bodies, con- 
sisting of a capsule formed by the expansion of the connective-tissue sheath of a 
medullated fibre, and containing a soft semifluid core in which the termination of 
the axis-cylinder is situated, ending either as a bulbous extremity, or in a coiled- 
up plexiform mass. End-bulbs are found in the conjunctiva of the eye, where 
they are spheroidal in shape in man, but cylindrical in most other animals, in the 
mucous membrane of the lips and tongue, and in the epineurium of nerve-trunks. 
They are also found in the genital organs of both sexes, the penis in the male, 
and the clitoris in the female. In this situation they have a mulberry-like appear- 
ance, from being constricted by connective-tissue septa into from two to six 
knob-like masses, and have received the name of genital corpuscles. Very similar 
corpuscles are found in the epineurium of nerve-trunks. In the synovial mem- 
brane of certain joints (e. g., those of the fingers) rounded or oval end-bulbs have 
been found; these are designated articular end-bulbs. 
Tactile Corpuscles, known as Grandry's corpuscles, have been described by 
Grandry as occurring in the papilhe of the beak and tongue of birds, and by 
Merkel as occurring in the papilla? and epithelium of the skin of man and animals, 828 
THE NERVOUS SYSTEM 
especially in those parts of the skin devoid of hair. They consist of a capsule com- 
posed of a very delicate, nucleated membrane, and contain two or more granular, 
somewhat flattened cells, between which the medullated nerve-fibre, which enters 
the capsule by piercing its investing membrane, is supposed to terminate. 
Meissner's corpuscles are the tactile corpuscles (Fig. 526), described by Wagner 
and Meissner. They are oval-shaped bodies, made up of connective tissue, 
and consisting of a capsule, and imperfect membranous septa, derived from it, 
which penetrate its interior. The axis-cylinder of the medullated fibres passes 
through the capsule, and having entered the corpuscle terminates in a small 
globular or pyriform enlargement, near the inner surface of the capsule. These 
tactile corpuscles have been described as occurring in the papilla* of the corium 
of the skin, hand, foot, front of the forearm, and skin of the lips, and the mucous 
membrane of the tip of the tongue, the palpebral conjunctiva, and the skin of the 
nipple. They are not found in all the papilhe, but from their existence in those 
parts in which the skin is highly sensitive, it is probable that they are especially 
concerned in the sense of touch, though their absence from the papilhe of other 
tactile parts shows that they are not essential to this sense. They may be regarded 
as end-bulbs. 
Ruffini has described a special variety of nerve-ending in the subcutaneous 
tissue of the human finger (Fig. 527). These are usually known as Ruffini's 
Nerve-fibres. 
Terminal ramifications 
of axis-cylinder. 
Connective-tissue sheath. 
Fig. 527.-Nerve-ending of Ruffini. (After A. Ruffini, Areh. ifal. de Biol., Turin, 1894, t. xxi.) 
nerve-endings. They are principally situated at the junction of the corium with the 
subcutaneous tissue; they are oval in shape, and consist of a strong connective- 
tissue sheath, inside which the nerve-fibre divides into numerous branches, which 
show varicosities and end in small free knobs. They resemble the corpuscles of 
Golgi. 
The Pacinian Corpuscles or Corpuscles of Vater (Fig. 528) are found in the 
human subject chiefly on the nerves of the palm of the hand and sole of the 
foot and in the genital organs of both sexes, lying in the subcutaneous tissue; 
but they have also been described as connected with the nerves of the joints, 
and in some other situations in the lower animals, as the mesentery of the 
cat and along the tibia of the rabbit. Each of these corpuscles is attached 
to and encloses the termination of a single nerve-fibre. The corpuscle which 
is perfectly visible to the naked eye (and which can be most easily demon- 
strated in the mesentery of a cat) consists of a number of lamellae or capsules, 
arranged more or less concentrically around a central clear space, in which the 
nerve-fibre is contained. Each lamella is composed of bundles of fine connective- 
tissue fibres, and is lined on its inner surface by a single layer of cells. 'The central 
clear space, which is elongated or cylindrical in shape, is filled with a transparent 
material, in the middle of which is the single medullated fibre, which traverses 
the space to near its distal extremity. Here it terminates in a rounded knob or 
end, sometimes bifurcating previously, in which case each branch has a similar ORIGIN AND TERMINATION OF NERVES 
829 
arrangement. rl odd and Bowman have described minute arteries as entering by 
the sides of the nerves and forming capillary loops in the intercapsular spaces, 
and even penetrating into the central space. 
Other authors describe the artery as entering the 
corpuscle at the pole opposite to the nerve-fibre. 
Herbst has described a somewhat similar 
'nerve-ending" to the Pacinian corpuscle, as 
being found in the mucous membrane of the 
tongue of the duck and in some other situations. 
It differs, however, from the Pacinian corpuscles 
in being smaller, its capsules thinner and more 
closely approximated, and especially in the fact 
that the axis-cylinder in the central clear space is 
coated with a continuous row of nuclei. These 
bodies are known as the corpuscles of Herbst. 
Neuro-tendinous Spindles.- The nerves supplying 
tendons have a special modification of the terminal 
fibres, especially numerous at the point where the 
tendon is becoming muscular. The tendon bundles 
become enlarged, and the nerve-fibres-one, two, 
or more in number-penetrate between the fas- 
ciculi of the tendon and spread out between the 
fibres to end in irregular disks or varicosities. A 
spindle-shaped body is thus formed, composed of 
tendon bundles and nerve-fibres, which is known 
as the organ of Golgi (Fig. 529). 
Neuro-muscular Spindles. - In the majority of 
voluntary muscles there have been found special 
end-organs consisting of a small bundle of pecu- 
liar muscular fibres (intrafusal fibres), embryonic 
in type, invented by a capsule within which nerve- 
fibres, experimentally shown to be sensory in 
origin, terminate. These neuro-muscular spindles 
vary in length from to F of an inch and have a 
distinctly fusiform appearance. The large medullated nerve-fibres passing to the 
end-organ are from one to three or four in number; entering the fibrous capsule 
Fig. 528.-Pacinian corpuscle, with its 
system of capsules and central cavity. 
a. Arterial twig, ending in capillaries, 
which form loops in some of the inter- 
capsular spaces, and one penetrates to 
the central capsule, b. The fibrous tis- 
sue of the stalk prolonged from the peri- 
neurium. n. Nerve-tube advancing to 
the central capsule, there losing the white 
matter, and stretching along the axis to 
the opposite end, where it is fixed by a 
tuberculous enlargement. 
Nerve-fibres. 
Organ of Golgi, showing 
ramification of nerve-fibrils. 
Tendon bundles. 
Muscular fibres. 
Fig. 529.-Organ of Golgi (neuro-tendinous spindle) from the human tendon Achillis. (After Ciaccio.) 
they divide several times, and, losing their medulla, ultimately end in naked axis- 
cylinders encircling the intrafusal fibres by flattened expansions, or irregular ovoid THE NERVOUS SYSTEM 
830 
or rounded disks (Fig. 530). Neuro-muscular spindles have not yet been demon- 
strated in the tongue or eye muscles. 
In the organs of special sense the nerves appear to terminate in cells which 
belong to the epithelial class, and have received the name of sensory or nerve- 
epithelium cells. This is not, however, the real state of the case; the nerve-fibre 
is in reality a process from the epithelial cell, and terminates by branching around 
a ganglion-cell. The stimulus carried by it is continued onward by an axis- 
cylinder, derived from the ganglion, to the brain. These nerve-epithelium cells 
must therefore be regarded as modified forms of nerve-cells. They will be more 
particularly described in connection with the description of the organs of special 
sense. 
Motor nerves are to be traced either into unstriped or striped muscular fibres. 
In the unstriped or involuntary muscles the nerves are derived from the sympa- 
Dendritic branchings. 
Bings. 
Spirals. 
Binns. 
Fig. 530.--Middle third of a terminal plaque in the muscle spindle of an adult cat. (After Ruffini.) 
Spirals. 
thetic, and are composed mainly of the non-medullated fibres. Near their termi- 
nation they divide into a number of branches, which communicate and form an 
intimate plexus. At the junction of the branches small triangular nuclear bodies, 
the ganglion-cells, are situated. From these plexuses minute branches are given 
off, which divide and break up into the ultimate fibrillae of which the nerve is com- 
posed. These fibrilhe course between the involuntary muscle-cells, and, according 
to Elischer, terminate on the surface of the cell, opposite the nucleus, in a minute 
swelling. Arnold and Frankenhauser believed that these ultimate fibrillae pene- 
trated the muscular cell and ended in the nucleus. More recent observation, 
however, has tended to disprove this. 
In the striped or voluntary muscle the nerves supplying the muscular fibres are 
derived from the cerebro-spinal nerves, and are composed mainly of medullated 
fibres. The nerve, after entering the sheath of the muscle, breaks up into fibres, 
or bundles of fibres, which form plexuses, and gradually divide until, as a rule, 
a single nerve-fibre enters a single muscular fibre. Sometimes, however, if the 
muscular fibre is long, more than one nerve-fibre enters it. Within the muscular 
fibre the nerve-fibre terminates in a special expansion, called by Kuhne, who first ORIGIN AND TERMINATION OF NERVES 
831 
accurately described it, the motorial end-plates (Fig. 531).1 The nerve-fibre, 
on approaching the muscular fibre, suddenly loses its white matter of Schwann, 
which abruptly terminates; the neurilemma becomes continuous with the sarco- 
Fig. 531.-Muscular fibres of Lacerta viridis with the terminations of nerves, a. Seen in profile, p p. The 
nerve end-plates, s s. The base of the plate, consisting of a granular mass with nuclei, b. The same as seen in 
looking at a perfectly fresh fibre, the nervous ends being probably still excitable. (The forms of the variously 
divided plate can hardly be represented in a wood-cut by sufficiently delicate and pale contours to reproduce 
correctly what is seen in nature.) c. The same as seen two hours after death from poisoning by curare. 
lemma of the muscle, and only the axis-cylinder enters the muscular fibre, where 
it immediately spreads out, ramifying like the roots of a tree, immediately beneath 
the sarcolemma, and is embedded in a layer of granular matter, containing a 
number of clear, oblong nuclei, the 
whole constituting an end-plate from 
which the contractile wave of the mus- 
cular fibre is said to start. 
The Ganglia may be regarded as sepa- 
rate small aggregations of nerve-cells, 
connected with each other, with the 
cerebro-spinal axis, and with the nerves 
in various situations. They are found 
on the posterior root of each of the 
spinal nerves; on the posterior or sensory 
root of the fifth cranial nerve; on the 
facial and auditory nerves; and on the 
glosso-pharyngeal and pneumogastric 
nerves. They are also found in a con- 
nected series along each side of the ver- 
tebral column, forming the trunk of the 
sympathetic; and on the branches of 
that nerve, generally in the plexuses or 
at the point of junction of two or more 
nerves with each other or with branches 
of the cerebro-spinal system. On sec- 
tion they are seen to consist of a reddish- 
gray substance, traversed by numerous 
white nerve-fibres; they vary consider- 
ably in form and size; the largest are 
found in the cavity of the abdomen; the smallest, not visible to the naked eye, 
exist in considerable numbers upon the nerves distributed to the different viscera. 
Fig. 532.- Section through a microscopic ganglion. 
Magnified 300 diameters, c. Capsule of the ganglion. 
n. Nerve-fibres passing out of the ganglion. The nerve- 
fibres which entered the ganglion are not represented. 
The nerve-fibres are ordinary medullated fibres, but the 
details of their structure are not shown, owing to the 
low magnifying power. The ganglion-cells are invested 
by special capsules, lined by a few nuclei, which are 
here represented as if contained in the capsule. (Klein 
and Noble Smith.) 
1 They had, however, previously been noticed, though not accurately described, by Doyere, who named them 
■" nerve-hillocks."-Ed. of 15th English edition. 832 
THE NERVOUS SYSTEM 
The ganglia are invested by a smooth and firm, elosely adhering membranous 
envelope, consisting of dense areolar tissue; this sheath is continuous with the 
perineurium of the nerves, and sends numerous processes into the interior of the 
ganglion, which support the blood-vessels supplying its substance. 
In structure all ganglia are essentially similar (Fig. 532), consisting of the same 
structural elements as the other nervous centres-viz., a collection of nerve-cells 
and nerve-fibres. Each nerve-cell has a nucleated sheath, which is continuous 
with the sheath of the nerve-fibre with which the cell is connected. The nerve- 
cells in the ganglia of the spinal nerves are pyriform in shape, and have only one 
process, the axis-cylinder or axone. A short distance from the cell, and while 
still within the ganglion, this process divides in a T-shaped manner, one limb 
of the cross-bar passing centrally and forming the central portion of a sensory 
nerve-fibre; the other limb passing peripherally to form the axis-cylinder process 
of the peripheral nerve-fibre. In the sympathetic ganglia the nerve-cells are 
multipolar and have one axis-cylinder process or axone and several protoplasmic 
processes or dendrons. The former of these emerges from the ganglion as a non- 
medullated nerve-fibre. Similar cells are found in the ganglia connected with the 
fifth cranial nerve, and these ganglia are therefore regarded by some as the cranial 
portions of the sympathetic system. The nerve-cells are disposed in the ganglia 
in groups of varying size, and these groups are separated from each other by 
bundles of nerve-fibres, some of which traverse the ganglia without being con- 
nected with the cells. 
THE CEREBRO-SPINAL AXIS. 
The cerebro-spinal axis consists of the spinal cord and the brain or encephalon, 
which are contained within the sktdl and spinal canal. The spinal cord and its 
coverings will be first considered, and then the brain and its membranes. 
THE SPINAL CORD AND ITS MEMBRANES. 
Dissection.-To dissect the cord and its membranes it will be necessary to lay open the 
whole length of the spinal canal. For this purpose the muscles must be separated from the 
vertebral grooves, so as to expose the spinous processes and laminae of the vertebrae; and the 
latter must be sawed through on each side, close to the roots of the transverse processes, from 
the third or fourth cervical vertebra above to the sacrum below. The vertebral arches having 
been displaced by means of a chisel and the separate fragments removed, the dura mater will be 
exposed, covered by a plexus of veins and a quantity of loose areolar tissue, often infiltrated with 
serous fluid. The arches of the upper vertebra* are best divided by means of a strong pair of 
cutting bone-forceps. 
MEMBRANES OF THE CORD. 
The membranes which envelop the spinal cord are three in number. The most 
external is the dura mater, a strong fibrous membrane which forms a loose sheath 
around the cord. The most internal is the pia mater, a cellulo-vascular membrane 
which closely invests the entire surface of the cord. Between the two is the arach- 
noid membrane, a non-vascular membrane which envelops the cord and is con- 
nected to the pia mater by slender filaments of connective tissue. 
The Spinal Dura Mater (Dura Mater Spinalis) (Figs. 533, 534, 535, 537). 
The spinal dura mater represents only the meningeal or supporting layer of 
the cranial dura mater. The endocranial or endosteal layer ceases at the foramen 
magnum posteriorly, but reaches as low as the third cervical vertebra in front; 
below these levels its place is taken by the periosteum. The dura mater forms a THE SPINAL DURA MATER 
833 
loose sheath which surrounds the cord and the cauda equina, and is loosely con- 
nected with the vertebral periosteum and the ligaments by a quantity of lax 
areolar tissue and a plexus of veins, the meningo-rachidian veins {plexus venosi 
vertebrales intemi). The space containing the fat and veins is called the epidural 
space (cavum epidurale}. The situation of the veins between the dura mater and the 
periosteum of the vertebra? corresponds therefore to that of the cranial sinuses 
between the endocranial and supporting layers. The dura is attached to the 
circumference of the foramen magnum and to the axis and third cervical vertebra; 
it is also fixed to the posterior common ligament, especially near the lower end of 
the spinal canal, by fibrous slips; it extends below as far as the second or third 
piece of the sacrum; here it becomes imper- 
vious, and, ensheathing the filum terminale, 
constitutes the filum durae matris spinalis (Fig. 
537), and descends to the back of the coccyx, 
to blend with the periosteum. This part of 
the dura is called the coccygeal ligament, 
DURA 
MATER 
SPINAL 
GANGLION 
ANTERIOR 
NERVE ROOT 
DENTATE 
LIGAMENT 
Dura 
Mater. 
Fig. 534-The dentate ligament. The dura 
mater has been opened and turned back. The 
anterior surface is seen. (Hirschfeld.) 
Fig. 533.-The spinal cord and its membranes. 
(Fig. 537). The dura mater is much larger than is necessary for its contents, 
and its size is greater in the cervical and lumbar regions than in the dorsal. 
Its inner surface is smooth. On each side may be seen the double openings, 
which transmit the two roots of the corresponding spinal nerve, the fibrous layer 
of the dura mater being continued in the form of a tubular prolongation on 
them as they pass through these apertures. These prolongations of the dura 
mater are short in the upper part of the spine, but become gradually longer 
below, forming a number of tubes of fibrous membrane, which enclose the sacral 
nerves, and are contained in the spinal canal. 
The chief peculiarities of the dura mater of the cord, as compared with that 
investing the brain, are the following: 
The dura mater of the cord is not closely adherent to the bones of the spinal 
canal, and is not, as is the cerebral dura, the internal periosteum of the vertebrae. 
The vertebrae have an independent periosteum. 834 
THE NERVOUS SYSTEM 
It does not send partitions into the fissures of the cord, as the cerebral dura 
sends partitions into certain fissures of the brain. 
Its fibrous laminae do not separate to form venous sinuses, as in the brain. 
It contains no Pacchionian bodies. 
Structure.-The dura mater consists of white fibrous and elastic tissue arranged 
in bands or lamellae, which, for the most part, are parallel with one another and 
have a longitudinal arrangement. Each surface is covered by a layer of endothelial 
cells. It is sparingly supplied with vessels, and some few nerves have been traced 
into it. 
The Arachnoid Membrane (Arachnoidea Spinalis) (Figs. 533, 535). 
The arachnoid is exposed by slitting up the dura mater and reflecting that 
membrane to either side. It is a thin, delicate, tubular membrane which invests 
the surface of the cord, and is connected to the pia mater by slender filaments 
of connective tissue. Above, it is continuous with the cerebral arachnoid; on 
each side it is continued on the various nerves, so as to form a sheath for them 
as they pass outward to the intervertebral foramina. The outer surface of the 
arachnoid is in contact with the inner surface of the dura mater, and the two 
are, here and there, joined together by isolated connective-tissue trabeculae. These 
trabeculae are especially numerous on the posterior surface of the cord. For the 
most part, however, the membranes are not connected together, and the interval 
between them is named the subdural space (cavum subdurale). The subdural 
space contains a very small amount of lymph-like fluid. There is no com- 
munication between the subdural space and the subarachnoid space. The sub- 
dural space is prolonged outward for a short distance on each emerging nerve 
and communicates with the lymph tract of the nerve. The inner surface of the 
arachnoid is separated from the pia mater by a considerable interval, which is 
called the subarachnoid or subarachnoidean space (cavum svbarachnoideale). The 
space is largest at the lower part of the spinal canal, and encloses the mass 
of nerves which form the cauda equina. Superiorly it is continuous with the 
cranial subarachnoid space, and communicates with the general ventricular 
cavity of the brain by means of openings in the pia mater, in the roof of the 
fourth ventricle, foramen of Majendie and foramina of Key and Retzius (p. 852). 
It contains an abundant serous secretion, the cerebro-spinal fluid (liquor cerebro- 
spinalis). This secretion is sufficient in amount to expand the arachnoid mem- 
brane, and thus to distend completely the whole of the space included in the 
dura mater. The subarachnoid space is occupied by trabeculae of delicate 
endothelial covered connective tissue, connecting the pia mater on the one 
hand with the arachnoid membrane on the other. This is named subarachnoid 
tissue. 
In addition to this the space is partially subdivided by a longitudinal mem- 
branous partition, the septum posticum or the posterior fenestrated septum (septum 
subarachnoideale), which serves to connect the arachnoid with the pia mater, 
opposite the posterior median fissure of the spinal cord. It is a partition, but an 
incomplete and cribriform partition, consists of bundles of white fibrous tissue 
interlacing with each other, and is coated with endothelium. The ligamenta 
denticulata, which run from the pia mater to the dura mater on either side of 
the cord, divide the subarachnoid space into an anterior and a posterior space 
(cavum subarachnoideale anterius et posterius), which join like spaces in the cavity 
of the cranium. The medulli-spinal veins (venae spinales erternae) lie in the sub- 
arachnoid space. 
Structure. - The arachnoid is a delicate membrane made up of closely 
arranged interlacing bundles of connective tissue in several layers. It con- THE PIA MATER OF THE CORD 
835 
tains many elastic fibres, and is covered on each side by endothelial cells. 
The arachnoid contains neither vessels or nerves. 
The Pia Mater of the Cord (Pia Mater Spinalis). 
The pia mater of the cord is exposed on the removal of the arachnoid (Figs. 533 
and 535). It covers the entire surface of the cord, to which it is very intimately 
adherent, forming its neurilemma, and sending a process downward into its ante- 
rior fissure. It also forms a sheath for each of the filaments of the spinal nerves, 
and invests the nerves themselves. A longitudinal fibrous band extends along the 
middle line on its anterior surface, called by Haller the linea splendens; and a 
somewhat similar band, the ligamentum denticulatum, is situated on each side. 
At the point where the cord terminates the pia mater becomes contracted, and is 
continued down as a long, slender filament, the filum terminale (Fig. 537), which 
descends within the sheath of the dura and 
the arachnoid and through the centre of the 
mass of nerves forming the cauda equina. It 
unites with the dura and arachnoid about the 
level of the third sacral vertebra, and as the 
central ligament of the spinal cord, the coccygeal 
ligament, or the filum durae matris spinalis the 
fused membranes extend downward as far 
as the base of the coccyx, where they blend 
with the periosteum. It assists in maintain- 
ing the cord in its position during the move- 
ments of the trunk. It contains a little gray 
nervous substance, which may be traced for 
some distance into its upper part, and is ac- 
companied by a small artery and vein. At 
the upper part of the cord the pia mater pre- 
sents a grayish, mottled tint, which is owing to yellow or brown pigment-cells 
scattered among the elastic fibres. 
Structure.-The pia mater of the cord is less vascular in structure, but thicker 
and denser, than the pia mater of the brain, with which it is continuous. It 
consists of two layers: an outer, resembling the arachnoid, composed of bundles 
of connective-tissue fibres, arranged for the most part longitudinally; and an inner 
(intima pia), consisting of stiff circular bundles of the same tissue, which present 
peculiar angular bends. It is covered on both surfaces by a layer of endothelium. 
Between the two layers are a number of cleft-like lymphatic spaces which com- 
municate with the subarachnoid cavity, and a number of blood-vessels which are 
enclosed in a perivascular sheath, derived from the inner layer of the pia mater, 
into which the lymphatic spaces open. The pia mater contains the anterior spinal 
artery and its branches, the two posterior spinal arteries, and numerous veins 
which pass to the medulli-spinal veins. It is also supplied with nerves, which are 
derived in part from the sympathetic and in part from the cerebro-spinal nerves. 
These nerves supply the walls of the blood-vessels and enter the cord with the 
vessels. 
The Dentate Ligament (ligamentum denticulatum) (Figs. 533 and 534) is a narrow 
fibrous band, situated on each side of the spinal cord, throughout its entire length, 
running from the pia mater to the dura mater, and separating the anterior from the 
posterior roots of the spinal nerves. It has received its name from the serrated 
appearance which it presents. Its inner border is continuous with the pia mater 
at the side of the cord. Its outer border presents a series of triangular, dentated 
serrations, the points of which are fixed at intervals to the dura mater. These 
Dura mater 
•Arachnoid 
Ganglion 
intervert 
•Post, root 
•Ant. root 
Dura mater 
Vasa vertebralia 
Plexus venosus 
Ftg. 535.-Transverse section of the spinal cord 
and its membranes. (Gegenbauer.) THE NERVOUS SYSTEM 
836 
serrations are twenty-one in number on each side, the 
first being attached to the dura mater, opposite the 
margin of the foramen magnum between the vertebral 
artery and the hypoglossal nerve, and the last near the 
lower end of the cord. Its use is to support the cord 
in the fluid bv which it is surrounded. 
Surgical Anatomy.-Evidence of value in the diagnosis of 
meningitis may be obtained by the operation of lumbar puncture, 
that is, by puncturing the theca of the cord and withdrawing 
some of the cerebro-spinal fluid, and the operation is regarded 
by some as curative, under the supposition that the draining 
away of the cerebro-spinal fluid relieves the patient by diminish- 
ing the intracranial pressure. Lumbar puncture may give im- 
portant diagnostic aid after a head injury by disclosing bloody 
cerebro-spinal fluid. The operation is performed by inserting a 
trocar, of the smallest size, below the level of the fourth lumbar 
vertebra. In an adult the cord terminates at the lower border 
of the first lumbar vertebra, and in a child opposite the body 
of the third lumbar vertebra. The canal may be punctured 
below the fourth vertebra without any risk of injuring its con- 
tents. The point of puncture is indicated by laying the child on 
its side and dropping a perpendicular line from the highest point 
of the crest of the ilium; this will cross the upper border of the 
spine of the fourth lumbar vertebra. In a child the puncture is 
made just below the vertebral spine. In adults one-half an inch 
to one side of the end of the vertebral spine. However the pre- 
liminary puncture is made, the needle penetrates the dura in the 
middle line. In entering the needle it should be directed up- 
ward and forward in a child; upward, forward, and slightly 
inward in an adult. 
THE SPINAL CORD (MEDULLA SPINALIS) (Fig. 536). 
The spinal cord is the cylindrical, elongated part of 
the cerebro-spinal axis which is contained in the verte- 
bral canal. Its length is usually about seventeen or 
eighteen inches, and its weight, when divested of its 
membranes and nerves, about one ounce and a half, 
its proportion to the encephalon being about 1 to 33. 
It does not nearly fill the canal in which it is con- 
tained, its investing membranes being separated from 
the surrounding walls by areolar tissue and a plexus of 
veins. It occupies, in the adult, the upper two-thirds 
of the vertebral canal, extending from the upper border 
of the atlas to the lower border of the body of the first 
lumbar vertebra, where it terminates in a slender fila- 
ment of gray substance, which is continued for some 
distance into the filum terminale (Fig. 537). In the 
foetus, before the third month, it extends to the bottom 
of the sacral canal, but after this period it gradually 
recedes from below, as the growth of the bones com- 
posing the canal is more rapid in proportion than that 
of the cord, so that in the child at birth the cord extends 
as far as the third lumbar vertebra. Its position varies 
also according to the degree of curvature of the spinal 
column, being raised somewhat in flexion of the spine. 
The spinal cord is cylindrical, being somewhat flattened 
Fig. 536.-Posterior view of the 
spinal cord in situ. THE SPINAL CORD 
837 
anteriorly and posteriorly (Fig. 538). On examining its surface it presents a 
difference in its diameter in different parts, being marked by two enlarge- 
ments, an upper or cervical, and a lower or lumbar. The cervical enlargement 
(intumescentia cervical is) extends from about the third cervical to the first or 
second dorsal vertebra; its greatest diameter is in the transverse direction (13 
mm.), and it corresponds with the origin of the nerves which supply the upper 
extremities. The lumbar enlargement (intumescentia lumbalis) is situated oppo- 
site the last two or three dorsal vertebrae, and corresponds with the origin of 
the nerves which supply the lower extremities. Below the lumbar enlargement 
the cord gradually tapers to form a cone, the conus terminalis (conus medullaris), 
the apex of which is continuous with the filum terminale. 
DURA 
'mater 
FILUM 
TERMINALE 
COCCYGEAL 
"ligament 
Fig. 537.-The filum terminale. (Poirier and Charpy.) 
Fissures and Grooves (Fig. 538).-It presents on its anterior or ventral sur- 
face, along the middle line, a longitudinal fissure, the anterior median or ventro- 
median fissure, and on its posterior or dorsal surface another fissure, which also 
extends along the entire length of the cord, the posterior median or dorso-median 
fissure or sulcus. These fissures penetrate through the greater part of the 
thickness of the cord, and incompletely divide the cord into symmetrical 
halves, united in the middle line by a transverse band of nervous substance, 
the commissure. 
The Anterior Median or Ventro-median Fissure (fissura mediana anterior) (Fig. 
538).-The anterior median fissure is wider, but of less depth, than the posterior, 
extending into the cord for about one-third of its thickness, and is deepest at the 838 
THE NERVOUS SYSTEM 
lower part of the cord. It contains a prolongation from the pia mater, and its 
floor is formed by the anterior or white commissure, which is perforated by numer- 
ous blood-vessels passing to the centre of the cord. 
The Posterior Median or Dorso-median Fissure or Sulcus (sulcus medianus pos- 
terior} (Fig. 538).-The posterior median sulcus is not an actual fissure, as the 
space between the lateral halves of the posterior part of the cord is crossed by 
connective tissue and numerous blood-vessels, so that no actual hiatus exists, 
and there is consequently no prolongation of the pia mater into it. It extends 
into the cord to about one-half its width. The floor of the posterior median 
sulcus is formed by the posterior or gray commissure. 
Lateral Fissures.-On each side of the posterior median fissure, along the line 
of attachment of the posterior roots of the nerves, a delicate fissure may be seen, 
leading down to the gray matter which approaches the surface in this situation; 
this is called the postero-lateral or dorso-lateral sulcus or fissure of the spinal cord 
(sulcus lateralis posterior}. On the posterior surface of the spinal cord, between 
VENTRAL MEDIAN 
FISSURE 
VENTRAL ROOTS 
VENTRAL HORN' 
LATERAL HORN 
RETICULAR- 
FORMATION 
DORSAL HORN- 
DO RSO-LATE R AL. 
FISSURE 
DORSAL ROOTS 
^°z> 
C°LUMN 
DORSAL MEDIAN 
FISSURE 
Fig. 538.-Transverse section of the spinal cord at the middle of the thoracic region. The neuroglia septum 
has been removed from between the dorsal columns. (Testut, after Pierret.) 
the posterior median fissure and the postero-lateral fissure on each side, is a slight 
longitudinal furrow, the posterior intermediate furrow or the posterior paramedian 
groove {sulcus intermedins posterior), marking off two slender tracts, the postero- 
median and postero-lateral columns. These are most distinct in the cervical 
region, but are stated by Foville to exist throughout the whole length of the 
cord. On each side of the anterior median fissure the anterior roots of the spinal 
nerves emerge from the cord, not in one vertical line, but by separate bundles 
which occupy an area of some width. This is called, by some anatomists, the 
antero-lateral fissure of the cord {sulcus lateralis anterior), although no actual 
fissure exists in this situation. 
Columns of the Cord {funiculi medullae spinalis) (Figs. 538 and 539).-Each 
half of the spinal cord is thus divided into four columns: an anterior column, a lateral 
column, a posterior column, and a postero-median column. This division, however, is 
very imperfect, since the limit between the so-called anterior and lateral columns 
cannot be defined on account of the bundles of the anterior roots being spread over THE SPINAL CORD 
839 
a considerable area. It is therefore customary to divide each half of the spinal cord 
into two columns, separated by the postero-lateral sulcus: (1) a small posterior 
column (funiculus posterior), which is bounded internally by the posterior median 
fissure, and externally by the postero-lateral sulcus, and the posterior column is 
subdivided by the posterior intermediate septum into an outer portion, the column 
or tract of Burdach (fasciculus cuneatus), and an inner portion, the column or tract 
of Goll (fasciculus gracilis)', (2) a large antero-lateral column, which comprises 
the rest of the cord. The antero-lateral column is divided arbitrarily into the 
lateral column (funiculus lateralis) and the anterior column (funiculus anterior). 
Structure of the Cord (Fig. 538).-If a transverse section of the spinal cord 
be made, it will be seen to consist of white and gray nervous substance. The 
white matter is situated externally, and constitutes the greater part. The gray 
substance occupies the centre, and is so arranged as to present on the surface of 
the section two crescentic masses, placed one in each lateral half of the cord, united 
together by a transverse band of gray matter, the gray commissure. Each cres- 
centic mass has an anterior or ventral horn (columna grisea anterior) and a posterior 
or dorsal horn (columna grisea. posterior). The posterior horn is long and narrow, and 
approaches the surface of the postero-lateral fissure, near which it presents a slight 
enlargement, the caput cornu; from this it tapers to form the apex cornu (apex 
columna grisea posterior), which at the surface of the cord becomes continuous 
with some of the fibres of the posterior roots of the spinal nerves. The constriction 
near the gray commissure is called the cervix cornu (cervix columna grisea posterior). 
The anterior horn is short and thick, and does not quite reach the surface, but 
extends toward the point of attachment of the anterior roots of the nerves. Its 
margin presents a dentate or stellate appearance. What is known as the lateral 
horn (columna grisea lateralis) projects from the outer aspect of the gray matter 
nearly on the line of the gray commissure. It is distinct in the upper dorsal region; 
in the cervical enlargement it is merged in the anterior horn, but it reappears in 
the upper cervical region. In the lumbar region it merges with the anterior horn. 
Owing to the projections toward the surface of the anterior and posterior horns 
of the gray matter, each half of the cord is divided by the gray matter, more or 
less completely, into three columns, anterior, middle, and posterior, the anterior 
and middle being joined to form the antero-lateral column, as the anterior horn 
does not quite reach the surface. 
The Commissure of the Spinal Cord.-The commissure of the spinal cord is com- 
posed of white and gray matter, and is therefore divided into the white and gray 
commissure. 
The Anterior or White Commissure (commissura anterior alba) is situated at the 
bottom of the anterior median fissure, and is formed of medullated nerve-fibres, 
which pass between the gray matter of the anterior horn and the anterior and 
lateral white columns of one side into similar parts on the other side. The 
fibres are oblique in direction; many which enter at the posterior part of the 
commissure on the one side leave it at the anterior part of the commissure on the 
other, and vice versa, a decussation taking place in the middle line. 
The Posterior or Gray Commissure (commissura grisea), which connects the two 
crescentic masses of gray matter, is separated from the bottom of the anterior 
median fissure by the anterior white commissure. It consists of transverse 
medullated nerve-fibres, with a considerable quantity of neuroglia between them. 
The fibres when they reach the lateral crescents diverge: some pass backward to 
the posterior roots; others spread out, at various angles, into the crescent. The 
portion of the gray commissure in front of the central canal is called the anterior 
gray commissure (commissura grisea anterior); the portion behind the central canal 
is called the posterior gray commissure (commissura grisea posterior). 
Running through the gray commissure of the whole length of the cord is a THE NERVOUS SYSTEM 
840 
minute canal, which is barely visible to the naked eye in the human cord, but is 
proportionately larger in some of the lower vertebrata. It is called the central 
canal (canalis centralis)', it opens above into the fourth ventricle, and terminates 
below in a somewhat dilated extremity, the inferior rhomboid fossa (fossa rhom- 
boidea inferior). It is surrounded by an area of neuroglia, which, in the recent 
state, has a gelatinous appearance, and in which there are no nerve-fibres. This 
is sometimes called the substantia gelatinosa centralis. When hardened in alcohol 
or chromic salts it has a finely reticulated appearance. The canal is lined in the 
foetus by columnar ciliated epithelium, but in the adult the cilia have disappeared, 
and the canal is filled with their remains. 
The mode of arrangement of the gray matter, and its amount in proportion to 
the white, vary in different parts of the cord. Thus, the posterior horns are long 
and narrow in the cervical region; short and narrower in the dorsal; short, but 
wider, in the lumbar region. In the cervical region the crescentic portions are 
small, and the white matter more abundant than in any other region of the cord. 
In the dorsal region the gray matter is least developed, the white matter being 
also small in quantity. In the lumbar region the gray matter is more abundant 
than in any other region of the cord. Toward the lower end of the cord the white 
matter gradually ceases. 'The crescentic portions of the gray matter soon blend 
into a single mass, which forms the only constituent of the extreme point of the 
cord. 
Blood Supply of the Cord.-Spinal branches are given off by the vertebral, 
ascending cervical, deep cervical, intercostal, lumbar, lumbar branches of the ilio- 
lumbar, lateral and middle sacral arteries.1 Many of these spinal arteries give 
branches to the cord and the branches reach the cord in the spinal nerve-roots 
and form three vascular chains in the cord. The arteries of the cord are the 
anterior spinal and the two posterior spinal, which take origin from the vertebral 
arteries (pp. 638 and 639). The anterior spinal lies at the surface of the anterior 
median fissure. The posterior spinal arteries descend on either side of the cord 
behind the posterior nerve-roots. The central supply of the cord is chiefly from 
the anterior spinal artery. It sends sulcal branches inward in the fissure toward 
the cord, and branches of these vessels enter the cord. The vessels of the cord 
are terminal arteries. The gray matter is chiefly supplied by the anterior spinal, 
partly by the posterior spinal. The white matter is supplied by both vessels. From 
the interior of the cord blood is brought by fissural veins (which emerge from the 
fissures), root-veins (which emerge with the fibres of the anterior and posterior 
roots), and a few veins which emerge from different parts of the surface of the 
cord. 'These vessels unite to form the medulli-spinal plexus, which is between the 
pia mater and the arachnoid membrane. (See Spinal Veins.) 
Lymphatics.-There are no lymph-vessels in the cord, but lymph is collected by 
perivascular lymph-spaces and by spaces about the nerve-fibres. 
Minute Anatomy of the Cord.-The cord consists of an outer part, composed 
of medullated nerve-fibres, which is the white substance; and of a central part, the 
gray matter, both supported in a stroma. 
The stroma is composed of connective tissue, which is derived from the pia by 
ingrowth, and hence is of mesodermic origin, and of neuroglia. 
The Neuroglia.-The neuroglia consists of a homogeneous transparent matrix, 
of a network of very delicate fibrillae, and of small stellate or branched cells, the 
neuroglia-cells. 
It takes origin from cells which were derived from the large columnar cells of 
the wall of the neural canal, and hence is of epithelial origin. 
1 A Manual of Practical Anatomy. By the late Prof. Alfred W. Hughes. Edited and completed by Arthur 
Keith, M.D. THE SPINAL CORL 
841 
In addition to forming a ground substance, in which the nerve-fibres, nerve- 
cells, and blood-vessels are embedded, a considerable accumulation of neuroglia 
takes place in three situations: (1) on the surface of the cord, beneath the pia 
mater; (2) around the central canal, the substantia gelatinosa centralis; and (3) 
as a cap over the extremity of the posterior horn, forming the substantia cinerea 
gelatinosa. 
The White Substance of the Cord (substantia alba).-The white substance of the 
cord is placed at the periphery and in the anterior commissure. It consists of 
medullated nerve-fibres, mostly disposed longitudinally, with blood-vessels and 
neuroglia, sustained by a network of connective tissue from the pia. When stained 
with carmine it presents a very striking appearance on transverse section. It is 
seen to be studded all over with minute dots, surrounded by white areas. This 
is due to the longitudinal medullated fibres seen on section. Each dot is an axis- 
cylinder, the white area about it is the substance of Schwann. Externally, the 
neuroglia forms a sheath closely in- 
vesting the outer surface of the cord 
immediately beneath the pia mater; 
from it numerous septa pass in- 
ward and separate the respective 
bundles of fibres and extend between 
the individual nerve-fibres, acting 
as a supporting medium, in which 
they are embedded. There are 
transverse, oblique or dorso-ventral 
and longitudinal fibres in the white 
substance. 
Transverse Fibres. - These fibres 
pass between the longitudinal tracts 
of the cord and the gray matter. 
They constitute the anterior or 
white commissure, which joins the 
anterior and lateral white columns 
and the anterior gray horn of one side 
to like parts of the opposite side. 
As previously stated, it is in front 
of the gray commissure, and is the 
floor of the anterior median fissure. 
It contains four sets of fibres: (1) 
those belonging to the direct pyram- 
idal tract, (2) those belonging to the 
antero-lateral ground bundle, (3) those belonging to the antero-lateral ascending 
cerebellar tract, (4) crossed fibres to the anterior spinal nerve-roots.1 
Oblique or Dorso-ventral Fibres.-These are the anterior root-fibres passing from 
the anterior gray horn to the periphery of the cord and the posterior root-fibres 
passing from the periphery of the cord to the posterior gray horn. 
Longitudinal Fibres.-They constitute the conducting tracts (Fig. 539). 
It is impossible to trace the course of the nerve-fibres in their passage through 
the cord; but the investigation of pathological lesions has shown that the white 
matter of the cord consists of certain columns or tracts of fibres; for it has been 
found that certain lesions are strictly limited to certain well-determined parts of 
the cord without involving neighboring regions. That these parts or fasciculi 
correspond to so many distinct anatomical systems, each endowed with special 
Crossed- 
pyramidal 
tract 
Fig. 539.-Columns of the cord. 
1 Santee. The Anatomy of the Brain and Spinal Cord. THE NERVOUS SYSTEM 
842 
functions, seems abundantly proved by the researches of Flechsig and others on 
the development of the spinal cord during the later periods of utero-gestation and 
in the newly born infant. By these researches several tracts can be traced along 
the greater part of the cord and into or from the encephalon (Fig. 539). Thus (1) in 
the antero-lateral column of the cord, on either side of the anterior median fissure, a 
portion of the column may be divided off as the uncrossed or direct pyramidal tract 
or the fasciculus of Turek (jasciculus cerebrospinalis anterior [ventralis]). This tract 
is a continuation of the corresponding tract in the medulla. It is only found in the 
upper part of the cord; it gradually diminishes as it is traced downward, and dis- 
appears about the middle of the dorsal region. It consists of centrifugal or descend- 
ing fibres which can be traced downward from the pyramid of the medulla of the 
same side, and are derived from the motor area of the cerebral cortex. The fibres 
of this tract decussate in their course down the cord, passing across the middle 
line through the anterior white commissure and terminating in the anterior gray 
horn of the opposite side; this explains the gradual diminution and eventual dis- 
appearance of the tract. (2) In the hinder part of the antero-lateral column is a 
somewhat triangular area, larger than the preceding, which is named the crossed 
pyramidal tract (jasciculus cerebrospinalis lateralis). In the cervical and dorsal 
regions the crossed pyramidal tract is overlaid by the direct cerebellar tract, but 
in the lumbar cord it is at the surface. This also consists of descending fibres, 
which are derived from the pyramid of the medulla of the opposite side, and 
which have crossed in the decussation of the pyramids. After crossing in the 
medulla the fibres descend and terminate about the cells in the anterior cornu 
of the same side as the column. The fibres are derived from the motor area 
of the cerebral cortex of the opposite side. Thus it will be seen that all the 
fibres from the motor area, which descend through the internal capsule, the crus 
cerebri, and the pons Varolii to the pyramidal body of the medulla, decussate. 
Some decussate in the lower part of the medulla, and descend through it as the 
crossed pyramidal tract. Others do not decussate in the medulla but descend as the 
direct pyramidal tract and cross through the anterior commissure of the cord to ter- 
minate in the anterior grayhornof the opposite side, where the fibres end by forming 
synapses around its cells. Investigations render it probable that the crossed pyram- 
idal tract contains some fibres from the main pyramidal tract in the medulla, which 
have descended from the corresponding side of the brain undecussated and terminate 
about the cells of the gray cornu of the same side of the cord. The crossed descending 
tract of the red nucleus is found within the crossed pyramidal tract at the junction of 
its lateral and dorsal portions. This tract from the opposite red nucleus reaches 
the lumbar cord and ends in the gray matter. (3) The antero-lateral tract is an 
extensive crescent-shaped strand which skirts the circumference of the anterior 
three-quarters of the antero-lateral column of the cord. Behind, where it is 
thickest, it lies in the angle formed by the direct cerebellar and crossed pyramidal 
tracts, becoming narrower as it passes forward toward the direct pyramidal tract. 
It contains two sets of fibres, centripetal or ascending, and centrifugal or descend- 
ing, and hence is divided into two tracts, the antero-lateral ascending and the 
antero-lateral descending cerebellar tracts, (a) The antero-lateral ascending cerebellar 
tract or the column of Gowers (jasciculus anterolateralis superficialis ascendens) 
is chiefly in the posterior part of the antero-lateral tract, although some of its 
fibres mingle with the descending tract. The axones which compose this tract 
arise from cells in the central gray matter and the gray matter of the base of the 
anterior horn, chiefly from the opposite side of the cord (Santee), most of the 
fibres crossing soon after their beginning by way of the anterior commissure. The 
fibres of the column of Gowers pass through the dorsal portion of the lateral region 
of the medulla (sending nerve fibres to the lateral nucleus) and the formatio reticu- 
laris of the pons, turn backward over the superior peduncle of the cerebellum, and THE SPINAL CORD 
843 
pass into the superior vermis through the valve of Vieussens (Santee, from Hoche). 
Between the ascending and descending tracts is the olivary bundle of the cord or the 
triangular tract of Helwig (tractus triangularis [Helwigi]}. It arises in the lumbar cord 
and terminates in the olive of the medulla. (6) The antero-lateral descending cere- 
bellar tract or the column of Marchi and Lowenthal (fasciculus anterolateralis super- 
ficialis descendens} is situated chiefly in the anterior portion of the antero-lateral 
tract, but some of its fibres are scattered among the fibres of Gowers' column. The 
axones of the descending tract are derived from Purkin jean cells in the cerebellar 
cortex. The fibres pass through the inferior peduncle of the cerebellum and the 
lateral region of the medulla and terminate in the anterior gray horn. (4) The 
direct cerebellar or dorso-lateral cerebellar tract (fasciculus cerebellospinalis} is situ- 
ated at the circumference of the cord behind the preceding and external to the 
crossed pyramidal tract, occupying a narrow area which extends backward as far 
as the postero-lateral fissure or nearly so. It commences at the upper level of the 
lumbar cord. Below this level it is absent, and where it is absent the crossed pyram- 
idal tract reaches the surface. As the direct cerebellar tract ascends it increases in 
size. It passes through the restiform body of the medulla and terminates in the 
superior vermis of the cerebellum. Its fibres are derived from the cells of the 
posterior vesicular column of Clarke in the gray matter of the cord. (5) Close to 
the point where the posterior roots enter the cord, in the antero-lateral column, is 
a small collection of fibres, which is known as the marginal tract of Spitzka and 
Lissauer (fasciculus 'marginalise, it is formed by some of the outer fibres of the 
posterior roots which run upward in the tract for a short distance, and end about 
the cell-bodies of the substantia gelatinosa (Santee). (6) The rest of the antero- 
lateral column of the spinal cord is occupied by the antero-lateral ground bundle 
(fasciculus proprius anterolateralis}. It surrounds the anterior cornu and sepa- 
rates the antero-lateral tract and the crossed pyramidal tract from the gray matter 
of the cord. Nowhere does it reach the surface of the cord, but at one place it very 
closely approaches it. The direct pyramidal tract separates it from the antero- 
median fissure. The fibres are very short and are commissural and associative. 
The portion of the ground bundle in the anterior column is chiefly commissural, 
its fibres passing between the anterior cornua. The portion in the lateral column 
is chiefly for association, its fibres joining different areas of the cord on the same 
side. It consists of (a) longitudinal fibres. An anterior longitudinal bundle (fas- 
ciculus longitudinalis medialis}, which ascends to reach the motor nuclei of cranial 
nerves and the subthalamic region. A posterior longitudinal bundle (fasciculus 
ventralis}, passing to the posterior corpus quadrigemina and the cilio-spinal and 
other centres (Santee). Longitudinal commissural fibres, which unite the groups 
of cells in the gray matter with one another; (6) of fibres which pass across the 
anterior commissure from the gray matter of the opposite side; and (c) horizontal 
fibres belonging to the anterior roots of the nerves, which pass through it before 
leaving the cord. In the posterior column of the cord there are two definite tracts. 
They are marked off from each other by the posterior intermediate furrow7 on the 
surface of the cord. The part which has been described previously as the posterior 
median column pretty nearly corresponds to the one tract, the tract of Goll, and 
the remainder of the posterior column corresponds to the other, the tract of Bur- 
dach. (7) The postero-median tract or tract of Goll (fasciculus gracilis} increases 
as it ascends, and consists of long, but small, fibres derived from the posterior 
roots of the spinal nerves, which ascend to the medulla oblongata, the fascic- 
ulus gracilis of the medulla, and end in the nucleus gracilis. Some fibres leave 
the tract and end in the gray matter of the cord. A few fibres pass to the 
thalamus and a few to the cerebellum. (8) The postero-lateral tract or the tract 
of Burdach (fasciculus cuneatus} consists of shorter, but larger, fibres than the 
preceding; they are derived from the posterior roots and from cells in the gray 844 
THE NERVOUS SYSTEM 
matter of the cord; some ascend only for a short distance in the tract and then 
enter the gray matter and come into close relationship with the cells of the pos- 
terior vesicular column of Clarke; others incline toward the mesial plane, and, 
entering Goll's column, can be traced as far as the medulla. The tract of Burdach 
becomes in the medulla the fasciculus cuneatus and the fasciculus of Rolando. 
Some of its fibres continue along the interolivary fillet, others along the arciform 
fibres, and some terminate in the gray matter of the cord (Santee). In the cervical 
and upper dorsal regions there is contained in the substance of Burdach's column 
a small strand of fibres, called the descending comma tract. It presents, on trans- 
verse section, the appearance of a comma, the blunt extremity of which is directed 
forward. The fibres forming it probably represent in part descending portions of 
the dorsal nerve-roots, together with descending commissural fibres within the 
cord itself. 
What is known as the cornu commissural tract is in the lumbar and lower dorsal 
regions, between the posterior cornu and the gray commissure. The septo- 
marginal tract is only found in a portion of the lumbar cord. It is between the 
septum and the dorsal surface of the cord (Santee). 
Functions of the Various Tracts in the Cord.-1. The direct pyramidal 
tract is motor, and conveys impulses chiefly to the arms and trunk. It conducts 
motor impulses from the cerebral cortex of one side, along the spinal cord of the 
same side, and to the multipolar nerve-cells of the anterior horn of the opposite 
side of the cord. A given muscular region is supplied chiefly by the crossed 
pyramidal tract of the corresponding side of the cord and partly by the direct 
pyramidal tract of the opposite side of the cord, but both tracts are innervated 
by the same brain area. It is further to be remembered that there are prob- 
ably direct or uncrossed fibres in the crossed pyramidal tracts of the cord which 
convey motor impulse from the cortex to muscles of the same side. 
2. The crossed pyramidal tract conveys motor impulses and impulses which 
control reflex movements. It descends from the cortex, decussates in the lower 
part of the medulla, and descends in the cord on the side opposite to the brain area 
from which it arose. It supplies muscles on the same side of the body as the tract 
is of the cord. This tract also contains a few uncrossed fibres from the same side 
of the brain. Hence the muscles of one side receive their chief innervation from 
the opposite side of the brain by way of the crossed and the direct pyramidal tracts, 
but receive some slight innervation from the same side of the brain by way of the 
direct fibres in the crossed pyramidal tract. Gowers1 says: "There is abundant 
evidence that each hemisphere of the brain is connected with both legs, although 
chiefly with that of the opposite side. 'There is also a similar and even more 
equal connection with the trunk muscles, and a slighter connection with certain 
muscles of the arm. Such muscles invariably regain some power on the paralyzed 
side, even with a complete interruption to the motor path, and they are weakened 
on the unparalyzed side." 
3. The antero-lateral descending cerebellar tract is a "segment of an indirect 
motor path" (Santee). 'The antero-lateral ascending cerebellar tract conveys 
impressions of temperature and pain. 
4. 'The direct cerebellar tract conveys impressions of equilibrium, particularly 
from the viscera. 
5. The antero-lateral ground bundle is associative between the anterior cornua 
and is commissural between different segments of the cord. 'These commissural 
and associative connections are of great importance, for if the regular route of 
nervous conduction is interrupted they may serve to convey the nerve current 
around the block. 
1 Diseases of the Nervous System. THE SPINAL CORD 
845 
6. The marginal tract of Spitzka and Lissauer is composed of ascending fibres 
from the posterior nerve-roots. 
7. The postero-lateral tract conveys impressions of common sensation. 
8. The postero-median tract conveys impressions of muscular sense. 
The Gray Substance of the Cord (substantia grisea).-The gray substance of the 
cord occupies its central part in the shape of two crescentic horns, joined together 
by the gray commissure. Each of these crescents has an anterior or ventral and 
a posterior or dorsal cornu. 
The Posterior or Dorsal Horn (columna grisea posterior) consists of a slightly nar- 
rowed portion, at its base, where it is connected with the rest of the gray substance 
-this is, the cervix cornu; from this it gradually expands into the main part of the 
horn, the caput cornu, and tapers to form the apex cornu; around its extremity is a 
lamina or layer of gelatinous material, which covers the head like a cap, and 
from this it tapers almost to a point, which approaches the surface of the cord at 
the postero-lateral groove. 
The gelatinous substance is a peculiar accumulation of neuroglia (Klein) 
similar to that found around the central canal, and has been named by Rolando 
the substantia cinerea gelatinosa. It probably takes its origin from the columnar 
cells which line the posterior part of the embryonic spinal canal. 
The Anterior or Ventral Horn of the Gray Substance (columna grisea anterior) in 
the cervical and lumbar swellings, where it gives origin to the motor nerves of the 
extremities, is much larger than in any other region, and contains several distinct 
groups of large and variously shaped cells. 
In addition to this, a lateral horn (columna grisea lateralis) is found projecting 
outward from the lateral region of the gray matter on a level with the gray com- 
missure in the upper part of the dorsal region of the cord; in the cervical and 
lumbar regions this lateral horn blends with the anterior horn, which thus becomes 
broad and expanded. From the concavity of the crescent, between the anterior 
and posterior horns, processes of gray matter extend into the white substance, 
where they divide and anastomose to form a network, termed the formatio reticu- 
laris. 
The gray commissure contains the central canal (canalis centralis), and is situated 
behind the white commissure, which separates it from the bottom of the anterior 
median fissure. 
The gray substance of the cord is composed of-(1) the substantia gelatinosa, 
which envelops the head of the posterior horn and which encircles the central canal 
of the cord; (2) the substantia spongiosa, which forms the crescentic horns (except 
the heads of the posterior horns and the envelope of the central canal). Further, 
it may be stated that the gray matter consists of nerve-fibres of variable but 
smaller average diameter than those of the white column; (3) nerve-cells of various 
shapes and sizes, with from two to eight processes; (4) blood-vessels and con- 
nective tissue. 
The nerve-fibres of the gray matter of the posterior horn are for the most part 
composed of a dense interlacement of minute fibrils, intermingled with nerves 
of a larger size. This interlacement is formed partly by the axones and dendrites 
of the cells of the gray matter, and partly by fibres which enter the gray matter 
and which come from various sources. 
The nerve-cells of the gray matter are collected into groups as seen on trans- 
verse section, but they really form columns of cells placed longitudinally; or else 
they are found scattered throughout the whole of the gray matter. 
In the anterior horn the cells consist of two chief groups; one medial, the more 
constant, near the anterior column; the other lateral, near the lateral column. 
The axones of these cells constitute the bulk of the anterior roots of the spinal 
nerves. The spinal nerves obtain axones from the entire lateral gray column and 846 
THE NERVOUS SYSTEM 
from part of the medial gray column of the same side, and also from the gray 
matter of the medial column of the opposite side by way of the white commissure. 
The nerve-fibres from these cells are distributed to the muscles of the trunk and 
extremities. A second lateral group is present in the cervical and lumbar enlarge- 
ments. In the centre of the gray crescent (substantia intermedia grisea) the cells 
are collected into three groups or columns. The intermedio-lateral column runs 
throughout the length of the cord, but is most distinct in the thoracic region. Its 
cells are in relation with fibres from the posterior nerve-roots and send off axones 
to the anterior nerve-roots. It is believed by Morris and others that these fibres are 
sympathetic and pass to glands and blood-vessels. Other axones enter the antero- 
lateral ascending cerebellar tract (Santee). The middle column is most distinct in the 
cervical cord. It certainly receives fibres from the posterior roots, and possibly 
sends fibres to the antero-lateral ascending cerebellar tract. At the base of the pos- 
terior horn on its inner side, adjoining the gray commissure, is a group of nerve- 
cells, called Clarke's posterior or dorsal column or Clarke's vesicular column (nuclei:.} 
dorsalis), which extends from the 
eighth cervical to the second lum- 
bar nerve. In the cervical and 
lumbar cord the nuclei of Stilling 
are its representatives, and in the 
medulla the accessory cuneate nu- 
cleus represents it. This column 
Fig. 540.-Formation of a spinal nerve. 
(Testut.) 
Fig. 541.-Dorsal roots entering cord and dividing into ascend- 
ing and descending branches, a. Stem-fibre, b, b. Ascending and 
descending limbs of bifurcation, c. Collateral arising from stem- 
fibre. (Van Gehuchten.) 
is in relation with the fibres of the posterior nerve-roots, and the axones from 
the cells of the column compose the direct cerebellar tract, and some, which are 
sympathetic, enter the anterior roots of the spinal nerves. In the posterior cornu 
are many cells not definitely arranged, but groups which are named peripheral, 
central, and basal. The axones of the cells of the posterior cornu enter the 
ground bundles, the column of Burdach, the anterior cornu of the same side, and 
the anterior and posterior cornua of the opposite side. Many fibres of the poste- 
rior roots are in relation with the cells of the posterior cornu. 
At the junction of the anterior and posterior cornua, in the outer portion of the 
gray matter, is a third group of cells, the lateral cell column; this is best seen in 
the dorsal region. In certain regions of the cord these cells extend in among 
the fibres of the white matter of the lateral column, and give rise to the lateral 
horn. THE DURA MATER OF THE BRAIN 
847 
In addition to these groups a few large scattered cells are found in the posterior 
horn and in the substantia gelatinosa of Rolando. 
Origin of the Spinal Nerves (Figs. 538 and 540).-The roots of the spinal nerves 
are attached to the surface of the cord, opposite the horns of gray matter. 
A Posterior Nerve-root enters the cord in two bundles, medial and lateral. The 
medial strand consists of coarse fibres which enter the outer part of the column of 
Burdach. The lateral strand is sometimes divided into a middle and an external 
bundle. The former contains large fibres, and passes through the gelatinous sub- 
stance of Rolando into the posterior horn. The external bundle consists of fine 
fibres which assume a longitudinal direction in the Spitzka-Lissauer tract. All the 
posterior root-fibres divide into ascending and descending branches on entering the 
cord, and these in their turn give off collaterals (Fig. 541). The fibres and their 
collaterals terminate by forming arborescences, some around the cells in the 
posterior horn, and others around the cells of Clarke's column, while the long 
ascending branches pass up in the columns of Goll and Burdach, and end by 
arborizing around the cells in the gracile and cuneate nuclei. Some of the fibres, 
however, pass to the gray matter of the opposite horn, and others to the anterior 
horn of the same side of the cord. 
Anterior Nerve-roots.-The majority of the fibres of the anterior nerve-roots are 
the continuations outward of the axones of the large or small multipolar cells in the 
anterior horn of gray matter. Some, however, appear to pass across in the anterior 
a white commissure to the cells in the anterior horn of the opposite side, while others 
extend backward to the posterior horn and outward to the lateral column of the 
same side. 
THE MENINGES OR MENINGEAL MEMBRANES OF THE BRAIN 
(MENINGES ENCEPHALI). 
Dissection.-To examine the brain with its membranes, the skull-cap must be removed. 
In order to effect this, saw through the external table, the section commencing, in front, about 
an inch above the margin of the orbit, and extending, behind, to a little above the level with 
the occipital protuberance. Then break the internal table with the chisel and hammer, to avoid 
injuring the investing membranes or brain; loosen and forcibly detach the skull-cap, when the 
dura mater will be exposed. The adhesion between the bone and the dura mater is very 
jntimate, and much more so in the young subject than in the adult. 
The membranes of the brain are from without inward: the dura mater, arachnoid 
membrane, and the pia mater. 
The Dura Mater of the Brain (Dura Mater Encephali) (Figs. 543,544,545,547). 
The dura mater of the brain is a thick and dense inelastic fibrous membrane 
which lines the interior of the skull. It is a covering for the brain and is also 
the internal periosteum. Its outer surface is rough and fibrillated, and adheres 
closelv to the inner surface of the bones by fibrous processes and blood-vessels. 
The adhesion is most marked on bony projections, opposite the sutures and at 
the base of the skull. Except at the sutures the adhesions are not dense, and 
between the fibrous processes which pass to the bone are spaces which are 
thought to be lymph-spaces, and are called epidural spaces. At these points 
the outer surface of the dura is covered with endothelium. Fibrous tissue 
passes through the open sutures and joins the outer layer of the dura to the 
external periosteum. It is known as the sutural membrane. The inner sur- 
face of the dura limits the subdural space. It is smooth and lined by a layer of 
endothelium. The dura mater sends four processes inward, into the cavity of 
the skull, for the support and protection of the different parts of the brain, and is 
prolonged to the outer surface of the skull through the various foramina which 848 
THE NERVOUS SYSTEM 
exist at the base, and thus becomes continuous with the pericranium; its fibrous 
layer forms sheaths for the nerves which pass through these apertures. At the 
base of the skull it sends a fibrous prolongation into the foramen caecum; it sends 
a series of tubular prolongations around the filaments of the olfactory nerves as 
they pass through the cribriform plate, and also around the nasal nerve as it passes 
through the nasal slit; a prolongation is also continued through the sphenoidal 
fissure into the orbit, and another is continued into the same cavity through the 
optic foramen, forming a sheath for the optic nerve, which is continued as far as the 
eyeball. In the posterior fossa it sends a process into the internal auditory meatus, 
ensheathing the facial and auditory nerves; another through the jugular foramen, 
forming a sheath for the structures which pass through this opening; and a third 
through the anterior condyloid foramen. Around the margin of the foramen mag- 
num it is closely adherent to the bone, and is continuous with the dura mater lining 
the spinal canal. The cavity or cave of Meckel {cavum Meckeli) (Fig. 545) is an 
osteo-fibrous recess near the apex of the petrous portion of the temporal bone, 
formed by folding of the dura mater in a bony depression. It contains the Gas- 
serian ganglion. In certain situations, as already mentioned (p. 736), the fibrous 
layers of this membrane separate to form sinuses for the passage of venous blood. 
Upon the outer surface of the dura mater, in the situation of the longitudinal sinus, 
may be seen numerous small, whitish bodies, the glandulae Pacchioni (p. 854). 
Structure (Fig. 542).-The dura mater consists of white fibrous tissue with 
connective-tissue cells and elastic fibres arranged in flattened lamin®, which are 
imperfectly separated by lacunar spaces and blood-vessels into two layers, 
endosteal and meningeal. The endosteal layer is the internal periosteum for the 
-BONE 
EN DOSTEAL 
LAYER 
DURA 
MATER 
MENINGEAL 
LAYER 
ENDOTHELIAL 
LINING 
Fig. 542.-The structure of the dura mater. Section through the cranial vault of a child, sligntly enlarged. 
(Poirier and Charpy.) 
cranial bones and contains the blood-vessels for their supply. At the margin 
of the foramen magnum it becomes continuous with the periosteum lining the 
spinal canal. The meningeal or supporting layer is lined on its inner surface by a 
layer of nucleated endothelium, similar to that found on serous membranes; 
these cells were formerly regarded as belonging to the arachnoid membrane. 
By its reduplication the meningeal layer forms the falx cerebri, the tentorium 
and falx cerebelli, and the diaphragma sellae. The two layers are connected by 
fibres which intersect each other obliquely. 
The Arteries of the Dura Mater (see section on Arteries).-Its arteries are very 
numerous, but are chiefly distributed to the bones. Those found in the anterior 
fossa are the anterior meningeal branches of the anterior and posterior ethmoidal 
and internal carotid, and a branch from the middle meningeal. In the middle 
fossa are the middle and small meningeal branches of the internal maxillary, a 
branch from the ascending pharyngeal, which enters the skull through the 
foramen lacerum medium basis cranii, branches from the internal carotid, and 
a recurrent branch from the lachrymal. In the posterior fossa are meningeal 
branches from the occipital, one of which enters the skull through the jugular 
foramen, and the other through the mastoid foramen;*the posterior meningeal, THE DURA MATER OE THE BRAIN 
849 
from the vertebral; occasionally meningeal branches from the ascending pharyn- 
geal, which enter the skull, one at the jugular foramen, the other at the anterior 
condyloid foramen, and a branch from the middle meningeal. 
The Veins of the Dura Mater.-The veins which return the blood from the dura 
mater (see p. 734), and partly from the bones, anastomose with the diploic veins 
(see p. 733). These vessels terminate in the various sinuses, with the exception 
of two which accompany the middle meningeal artery, and pass out of the skull 
at the foramen spinosum to join the internal maxillary vein; above, the meningeal 
veins communicate with the superior longitudinal sinus. The sinuses are con- 
sidered on pages 736 to 743 inclusive. On either side of the superior longitu- 
dinal sinus, especially near its middle, and also near the lateral and straight 
sinuses, are numerous spaces in the dura mater which communicate with the 
sinus, either by a small opening or a distinct venous channel. These spaces are 
the parasinoidal sinuses (lacunae laterales} (Fig. 453). Many of the meningeal 
veins do not open directly into the sinuses, but indirectly through the parasinoidal 
sinuses. These venous lacunae are often invaginated by Pacchionian bodies, and 
they communicate with the underlying cerebral veins, and also with the diploic 
and emissary veins. 
The Lymphatics of the Dura Mater.-The existence of lymphatic vessels is not 
proved. Some anatomists claim to have injected such vessels along the middle 
meningeal arteries (Mascagni, Arnold). Perivascular lymph-spaces do exist. 
The Nerves of the Dura Mater.-The nerves of the dura mater are filaments from 
the fourth, the ophthalmic division of the fifth, the Gasserian ganglion, the pneumo- 
gastric, the hypoglossal, and the sympathetic. 
Processes of the Dura Mater (processus durae matris').-The processes of the 
dura mater, sent inward into the cavity of the skull, are four in number: the falx 
cerebri, the tentorium cerebelli, the falx cerebelli, and the diaphragma sellae. 
SUPERIOR LONGI- 
TUDINAL SINUS 
FALX 
CEREBRI 
TENTORIUM 
'CEREBELLI 
LATERAL 
SI NUS 
FALX CEREBELLI 
Fig. 543. Crucial prolongation of the dura mater. Frontal section passing through the tentorium cerebelli. 
The torcular Herophili is seen in the centre. (Poirier and Charpy.) 
The Falx Cerebri (Figs. 543 and 545).-The falx cerebri, so named from its 
sickle-like form, is a strong arched process of the dura mater, which descends 
vertically in the longitudinal fissure between the two hemispheres of the brain. 
It is narrow in front, where it is attached to the crista galli of the ethmoid bone, 
and broad behind, where it is connected with the upper surface of the tentorium. 
Its upper margin is convex, and attached to the inner surface of the skull, in the 850 
THE NEE VO US SYSTEM 
middle line, as far back as the internal occipital protuberance; it contains the 
superior or great longitudinal sinus (sinus sagittalis superior). Its lower margin 
is free, concave, and presents a sharp curved edge, which contains the inferior 
longitudinal sinus (sinus sagittalis inferior). The straight sinus (sinus rectus) is 
formed by the attachment of the falx cerebri to the tentorium cerebelli. 
The Tentorium Cerebelli (Figs. 543, 544, and 545).-The tentorium cerebelli is 
an arched lamina of dura mater, elevated in the middle and inclining downward 
DIAPHRAGMA SELLAE 
ANTERIOR 
-CLINOID 
PROCESS 
INCISURA 
"TENTORII 
TENTORIUM 
CEREBELLI 
TORCULAR 
"HEROPHILI 
Fig. 544.-The tentorium cerebelli. (Poirier and Charpy.) 
toward the circumference. It covers the upper surface of the cerebellum, and 
supports the occipital lobes of the brain, and prevents them pressing upon the 
cerebellum. It is attached, behind, by its convex border to the transverse ridges 
upon the inner surface of the occipital bone, and there encloses on each side the 
lateral sinus (sinus transversus); in front, to the superior margin of the petrous 
portion of the temporal bone on either side, enclosing the superior petrosal 
sinus (sinus petrosus superior); and at the apex of this bone the free or internal 
border and the attached or external border meet, and, crossing one another, are 
continued forward, to be attached to the anterior and posterior clinoid processes 
respectively. Along the middle line of its upper surface the posterior border 
of the falx cerebri is attached, the straight sinus being placed at their point of 
junction. Its anterior border is free and concave, and with the dorsum sellae 
forms a large oval opening. This opening is called the incisura tentorii and 
transmits the mesencephalon. 
The Falx Cerebelli (Fig. 543).-The falx cerebelli is a small triangular process 
of dura mater received into the indentation between the two lateral lobes of the 
cerebellum behind. Its base is attached, above, to the under and back part of THE ARACHNOID MEMBRANE 
851 
the tentorium; its posterior margin, to the lower division of the vertical crest on 
the inner surface of the occipital bone. As it descends it sometimes divides into 
two smaller folds, which are lost on the sides of the foramen magnum. 
The Diaphragma Sellae (Fig. 544).-The diaphragma sellae is a horizontal process 
formed by a reduplication of the meningeal layer of the dura mater. It forms 
a small circular fold, which constitutes a roof for the sella turcica. This almost 
^INTERNAL JUGULAR 
VEIN 
Fig. 545.-Falx cerebri and tentorium, left lateral view. (Testut.) 
completely covers the pituitary body, presenting merely a small central opening 
(foramen diaphragmaiis sellae) for the infundibulum to pass through. 
The Arachnoid Membrane (Arachnoidea Encephali) (Fig. 546). 
The term arachnoid is from the Greek apdyvy etdo$, like a spider's web, so 
named for its extreme thinness. The cranial arachnoid is a delicate membrane 
which envelops the brain, lying between the pia mater internally and the dura 
mater externally; from this latter membrane it is separated by a very fine slit or 
space, the subdural space (cavum subdurale). The subdural space contains a very 
minute quantity of fluid of the nature of lymph. This fluid obtains exit by way 
of the parasinoidal sinuses. The subdural space is prolonged upon emerging 
nerves and joins the lymph spaces of the nerves. The subdural space does not 
communicate with the subarachnoid space. 
The arachnoid invests the brain loosely, being separated from direct contact 
with the cerebral substance by the pia mater, and a quantity of loose areolar 
tissue, the subarachnoidean areolar tissue. On the upper surface of the cere- 
brum the arachnoid is thin and transparent, and may be easily demonstrated by 852 
THE NERVOUS SYSTEM 
injecting a stream of air beneath it by means of a blowpipe; it passes over the 
convolutions without dipping down into the sulci between them, but does pass 
into the Sylvian and great longitudinal fissures and is prolonged upon the nerves 
as a sheath. At the base of the brain the arachnoid is thicker, and slightly 
opaque toward the central part; it covers the orbital surface of the anterior 
lobes, and extends across between the two temporal lobes so as to leave a con- 
siderable interval between it and the brain, the cisterna basalis. 
The Subarachnoid Space (cavum subarachnoideale) (Fig. 547).-The subarach- 
noid space is the interval between the arachnoid and pia mater. It is not only on 
OLFACTORY 
NERVE 
OPTIC 
NERVE 
CAROTID 
ARTERY 
THI RD 
NERVE 
BASILAR 
ARTERY 
VERTEBRAL 
ARTERY 
Fig. 546.-The arachnoid upon the base of the brain. On the right the arachnoid has been partly removed 
to show the cerebrum and cerebellum with their superficial veins. (Poirier and Charpy.) 
SPINAL 
ARACHNOID 
the surface, but dips between the convolutions. It is not, properly speaking, 
a space, for it is occupied everywhere by a spongy tissue consisting of trabeculae 
of delicate connective tissue covered with endothelium, which pass from the pia 
mater to the arachnoid, and in the meshes of which the subarachnoid fluid is con- 
tained. This so-called space is small on the surface of the hemispheres; but at 
the base of the brain the subarachnoid tissue is less abundant and its meshes 
larger. 
In certain regions the arachnoid and pia are farther apart than was previously 
indicated, and these spaces are called subarachnoid cisternae (cisternae subarach- 
noidalis}. The largest space is the continuation of the posterior part of the sub- 
arachnoid space of the spinal cord. It is called the posterior subarachnoid space THE ARACHNOID MEMBRANE 
853 
or cisterna magna (cisterna cerebellomedullaris). It is a space formed by the 
arachnoid passing across the back and under portions of the medulla and cere- 
bellum. It communicates with the fourth ventricle by three foramina. The 
largest opening is the foramen of Majendie (apertura medialis ventriculi quart!). 
It is in the middle line of the tela choroidea inferior. At the end of each recessus 
lateralis of the fourth ventricle there is also an opening, and each opening is 
called the foramen of Key and Retzius (apertura lateralis ventriculi quart!). 
The cisterna pontis is the continuation upward of the anterior part of the sub- 
arachnoid space of the cord. About the medulla it is continuous with the 
cisterna magna, so this important nerve centre is surrounded by a large sub- 
arachnoid space. The cisterna basalis (cisterna interpeduncularis) is formed 
by the arachnoid extending between the two temporal lobes, and it contains the 
arteries forming the circle of Willis. The anterior subarachnoid space (cisterna 
pontis, inter peduncular is et chiasmatis) includes the cisterna pontis, the cisterna 
basalis and the cisterna of the chiasm. There is a cisterna between the inferior 
edge of the falx cerebri and the superior surface of the corpus callosum which 
contains the anterior cerebral arteries, a cisterna in the fissure of Sylvius which 
contains the anterior cerebral artery, and a cisterna between the corpora quad- 
rigemina which contains the vena magna Galeni. 
It is stated by Merkel that the lateral ventricles also communicate with the 
subarachnoid space at the apices of their descending horns. 
ARACHNOID 
PIA MATER 
CONVOLUTION 
OF BRAIN 
Fig. 547.-The subarachnoid space. (Schematic.) (Poirier and Charpy.) 
The cerebro-spinal fluid (liquor cerebrospinalis) fills the subarachnoid space. It 
is a clear, limpid fluid, having a saltish taste and a slightly alkaline reaction. 
According to Lassaigne, it consists of 98.5 parts of water, the remaining 1.5 per 
cent, being solid matters, animal and saline. It varies in quantity, being most 
abundant in old persons, and is quickly reproduced. Its chief use is probably 
to afford mechanical protection to the nervous centres, and to prevent the effects 
of concussions communicated from without. 
Structure.-The arachnoid consists of bundles of connective tissue, the fine 
fibres of which form one layer and cross each other in every direction. At the 
level of the large fissures, and especially around the circle of XX illis, it is reinforced 
by thick fibrous tissue. Both surfaces are covered with endothelium. There are 
no blood-vessels in the arachnoid; the vessels which appear to be in it are really 
in the pia. There is no positive proof that nerves are present in the arachnoid. 
It is true that Bochdalek and Luschka long ago described arachnoid nerves, but 
these observations have never been corroborated. 854 
THE NERVOUS SYSTEM 
Glandulae Pacchioni, Luschka's Villi or the Arachnoid Villi (Granulationes 
Arachnoideales). 
The glandulae Pacchioni are numerous small whitish or purplish projections, 
usually collected into clusters of variable size, which are found in the following 
situations: 1. Upon the outer surface of the dura mater, in the vicinity of the 
superior longitudinal sinus, being received into little depressions on the inner 
surface of the calvarium. 2. On the inner surface of the dura mater. 3. In the 
superior longitudinal sinus and the other sinuses. 4. On the pia mater, near 
the margin of the hemispheres. 
A hasty examination would lead us to suppose that these bodies spring from 
the dura, but, as a matter of fact, they originate from the arachnoid. They are 
not glandular in structure, but are simply enlarged normal villi of the arachnoid. 
In their growth they appear to perforate the dura mater, and when a group of 
villi is of large size it causes absorption of the bone, and comes to be lodged in a 
pit or depression (foveola granularis [Pacchioni]) on the inner table of the skull. 
Their manner of growth is as follows: at an early period they project through 
minute holes in the inner layer of the dura mater, which open into large venous 
spaces situated in the tissues of the membrane, on either side of the longitudinal 
sinus and communicating with it. In their onward growth the villi push the outer 
layer of the dura mater before them, and this forms over them a delicate mem- 
branous sheath. In structure they consist of spongy trabecular tissue, covered 
over by a membrane, which is continuous with the arachnoid. The space between 
these two coverings, derived from the dura mater and arachnoid respectively, 
corresponds to and is continuous with the subdural space. The spongy tissue of 
which they are composed is continuous with the trabecular tissue of the sub- 
arachnoid space; so that fluid injected into the subarachnoid space finds its 
way into the Pacchionian bodies, and through their coverings filters into the 
superior longitudinal sinus. They are supposed to be a means of getting rid of 
an excess of cerebro-spinal fluid-, when its quantity is increased above normal. 
Another means of getting rid of cerebro-spinal fluid is absorption by the lymph- 
spaces of the cranial nerves, which possess sheaths of arachnoid up to the points 
at which they emerge from the skull. 
These bodies are not found in infancy, and very rarely until the third year. 
They are usually found after the tenth year; and from this period they increase 
in number as age advances. Occasionally they are wanting. 
The Pia Mater of the Brain (Pia Mater Encephali) (Figs. 547, 548). 
The pia mater of the brain is a vascular membrane, and derives its blood from 
the internal carotid and vertebral arteries. It consists of a minute plexus of blood- 
vessels, held together by an extremely fine areolar tissue. It invests the entire 
surface of the brain, dipping down between the convolutions and lamina?, and 
is prolonged into the interior, forming the velum interpositum and the choroid 
plexuses of the lateral and fourth ventricles. 
The Velum Interpositum or the Tela Chorioidea Superior (tela chorioidea 
ventriculi tertii) (Fig. 548).-The velum interpositum is the prolongation of the 
pia mater into the interior of the brain through the middle of the transverse 
fissure. It is a double triangular vascular fold, lies between the body of the 
fornix above and the optic thalami and the epithelial roof of the third ventricle 
below, and passes forward to the foramen of Monro. At each edge of the 
velum interpositum is the choroid plexus (plexus chorioideus ventriculi lateralis') 
of the corresponding lateral ventricle. In front the two plexuses join behind THE PIA MATER OF THE BRAIN 
855 
ANTERIOR PILLAR 
OF FORNIX" 
CAUDATE 
NUCLEUS 
FORAMEN OF 
MONRO 
MEDIAN 
PLEXUS 
CHOROID 
"vein 
-.VELUM 
CHOROID 
PLEXUS 
VEINS OF 
GALEN 
VENA MAGNA 
GALENI 
Fig. 548.-Velum interpositum. (Poirier and Charpy.) 
FRONTAL. 
LOBE* 
ANTERIOR 
CEREBRAL 
ARTERY 
ANTERIOR 
'COMMUNICATING 
ARTERY 
MIDDLE 
CEREBRAL 
ARTERY 
INTERNAL 
CAROTID 
ANTERIOR 
CHOROID- 
ARTERY 
POSTERIOR 
COMMUNICATING 
ARTERY 
OPTIC 
TRACT' 
BASI LAR 
ARTERY 
EXTERNAL 
GENICULATE 
BODY- 
INSULA 
POSTERIOR 
CEREBRAL 
ARTERY 
INTERNAL 
GENICULATE 
BODY 
CORPORA 
QUADRIGEMINA 
PULVINAR 
MIDDLE CORNU 
OF LATERAL 
VENTRICLE 
OCCIPITAL 
LOBE 
Fig. 549.-The anterior cerebral and choroid arteries. (Spalteholz.) THE NERVOUS SYSTEM 
856 
the foramen of Monro, and at the point of junction two lesser choroid plexuses 
pass back along the under surface of the velum to the third ventricle, the median 
plexus (plexus chorioideus ventriculi tertii). The veins of Galen or the deep 
cerebral veins (p. 735) are two veins which lie on either side of the middle of the 
velum interpositum and pass back. Each vein of Galen is formed by the union 
of the vein from the corpus striatum and the choroid vein from the choroid 
plexus. The two veins of Galen unite and form the vena magna Galeni, which 
empties into the straight sinus. 
The pia mater of the surfaces of the hemispheres, where it covers the gray 
matter of the convolutions, is very vascular, and gives off from its inner surface 
a multitude of minute vessels, which extend perpendicularly for some distance 
into the cerebral substance. At the base of the brain, in the situation of the 
anterior and posterior perforated spaces, a number of long straight vessels are 
given off, which pass through the white matter to reach the gray substance in the 
CALLOSO-MARGIN AL 
FISSURE 
PA R I ETO-OCCI PITAL 
SULCUS 
.CUNEUS 
ANTERIOR CERE- 
BRAL ARTERY 
OPTIC 
NERVE' 
CALCARINE 
FISSURE 
ANTERIOR COM- 
MUNICATING ARTERY 
INTERNAL 
CAROTID 
ARTERY 
POSTERIOR 
COMMUNICATING 
ARTERY 
POSTERIOR 
CEREBRAL 
ARTERY 
Fig. 550.-The arteries of the medial surface of the right cerebral hemisphere. (Spalteholz.) 
interior. On the cerebellum the membrane is more delicate, and the vessels from 
its inner surface are shorter. The pia mater of the spinal cord is thicker, firmer, 
and less vascular than that of the brain, and as it is traced upward over the 
medulla it is seen to preserve these characters. At the upper border of the medulla 
it is prolonged over the lower half of the fourth ventricle, forming a covering for 
it called the tela chorioidea inferior (tela chorioidea ventriculi quarti), before it is 
reflected on to the under surface of the cerebellum, and which carries the choroid 
plexus of the fourth ventricle (plexus chorioideus ventriculi quarti). 
The arteries of the pia mater (see pp. 626, 627, and 628) (Figs. 549 and 550) 
are the anterior cerebrals, middle cerebrals, posterior cerebrals, anterior choroids, 
posterior choroids, the superior cerebellars, and the anterior and posterior inferior 
cerebellars. (The vessels of the cerebral ganglionic system and of the cortical 
arterial system are considered on pp. 630 and 631.) 
The veins of the pia mater (see pp. 734, 735, and 736) are the basilar vein, 
the veins of Galen (Fig. 548), the veins constituting the choroid plexuses of the IHE BRAIN 
857 
third ventricle, the lateral ventricles, and the fourth ventricle; the cerebral veins 
(Fig. 546) and the cerebellar veins (Fig. 546). 
The nerves of the pia mater accompany the branches of the arteries and are 
derived from the sympathetic and from the third, fifth, sixth, seventh, ninth, tenth, 
and eleventh cranial nerves. 
According to Fohmann, Arnold, and Mascagni, this membrane contains numer- 
ous lymphatic vessels, but the question is uncertain. 
THE BRAIN (ENCEPHALON). 
The encephalon or brain is that portion of the cerebro-spinal axis which is 
contained in the cavity of the cranium. 
The Development of the Brain.-The nervous system (brain, ganglia, spinal 
cord, and nerves) is derived from the ectoderm (the epiblastic layer of the blasto- 
dermic vesicle). This, it will be remembered, is an epithelial layer, and nervous 
structure is composed of epithelial cells variously modified. The embryonal area 
of the surface of the developing germ is a white spot, which at first is round, but 
becomes pear-shaped and develops a transverse ridge, the terminal ridge, on its 
posterior margin. From the embryonal layer, and from this alone, the new indi- 
vidual is developed. 
About the twelfth or the thirteenth day of the development of the human 
embryo, cell-proliferation occurs at a certain portion of the under surface of the 
ectoderm. This proliferation gives rise to a white, longitudinal streak in the 
embryonal area, known as the primitive streak or axis plate. The head process of 
the primitive streak appears somewhat later, and is situated directly in front 
of the anterior end of the streak. 
At the anterior end of the primitive streak is a group of epiblastic cells known 
as Hensen's node. The epiblastic cells of the head-process of the primitive streak 
enlarge and become columnar, and the cells at each side of the streak become 
flat (Heisler). Thus is formed from the ectoderm the medullary plates; and the 
turning up of the edge of the medullary plates forms the spinal or medullary 
furrow or groove. As the curling up of the edges of the medullary plates continues 
the groove deepens, finally becoming a tube known as the medullary or neural tube 
or canal. 
The neural tube lies beneath the ectoderm; is finally separated from it; runs 
from one end of the body to the other; forms the primitive nervous system, and 
gives origin to the entire nervous system. The constricted portion between the 
hind-brain and the mid-brain is known as the isthmus rhombencephali. 
It is thus seen that the medullary or neural groove is converted into a canal, 
the neural canal. Its cephalic end dilates into a sac, from which the brain is 
developed, and the remainder forms the spinal cord. In consequence of the curve 
that the cephalic portion of the embryo undergoes, a marked bend in the canal 
takes place forward, so that the plane of the ventricles is placed almost at a right 
angle with the long axis of the central canal of the cord. The rudimentary brain 
consists of a hollow sac-the rudimentary cord of a hollow canal. The sac and 
the canal communicate freely with each other. 
The sac elongates, and in it appear two constrictions, which partially divide it 
into three portions, namely, the anterior, middle, and posterior primitive cerebral 
vesicles, or the fore-brain (prosencephalon), the mid-brain (mesencephalon), and the 
hind-brain (rhombencephalon) (Fig. 551). Subsequently the anterior and the pos- 
terior vesicles become constricted, each into two, while the middle remains 
undivided (Figs. 553 and 554). It will thus be seen that at the anterior 
extremity of the medullary canal there are five dilatations, separated from each 858 
THE NERVOUS SYSTEM 
other by constrictions, through which, however, they freely communicate with 
one another. These five vesicles are the fundamental or primitive divisions of 
the adult brain. They are named, from before backward, the fore-brain (pros- 
encephalon), the inter-brain (thalamencephalon, formed from the prosencephalon), 
the mid-brain (mesencephalon), the upper portion of the hind-brain (metencephalon), 
Head fold of amnion. 
Forebraiii. 
Optic vesicle. 
Midbrain. 
Hindbrain. 
Auditory vesicle. 
Heart. 
Omphalo-mesenteric vein. 
Protorertebrse or 
mesoblastic somites. 
Medullary ridge. 
■Sinus rhomboidalis. 
Remains of primitive 
streak. 
Fig. 551.-Chick embryo of thirty-three hours' incubation, viewed from the dorsal aspect. X 30. 
(From Duval's Atlas d'Embryologie.) 
and the lower portion of the hind-brain (myelencephalon). The constricted por- 
tion between the hind-brain and the mid-brain is known as the isthmus rhomb- 
encephali. 
These five vesicles are at first fairly uniform in size and in shape, but they soon 
begin to grow at different rates and to assume different forms. The changes are 
most marked in the first vesicle. THE BRAIN 
859 
The first secondary vesicle sends out two hollow protrusions, one on each side, 
from the forepart of its lateral surface. These grow rapidly, spread out, and 
extend forward, laterally, and backward, over the sides of the first and second 
ventricles, forming large cavities, which become the lateral ventricles (Fig. 552, G). 
From each protrusion three prolongations take place: one forward and out- 
ward; the second backward and inward, and the 
third at first backward, outward, and downward, 
and then forward and inward. These prolonga- 
tions form the horns of the lateral ventricles, and 
they far exceed in size the original vesicle from 
which they have taken origin, which does not 
increase to any great extent, but remains as the 
anterior part of the third ventricle. The com- 
munication between it and the future lateral ven- 
tricle persists as the foramen of Monro (Fig. 552). 
The second vesicle or thalamencephalcn be- 
comes elongated from before backward and com- 
pressed laterally, so as to form the greater part 
of the third ventricle (Fig. 552, BY From each 
side of that part of the fore-brain, which ulti- 
mately becomes the lateral ventricle, is budded 
off a hollow projection, the primary optic vesicle, 
that is developed eventually into the optic nerve 
and the retina. It will be considered later. 
The constriction between the first and the 
second vesicle disappears, so as to throw the 
wThole cavity of the future third ventricle, formed 
by the remains of the first ventricle and the whole 
of the second vesicle, into one. 
The third vesicle or mesencephalon forms a 
very insignificant part of the brain of the adult. 
It constitutes a stem of junction between the 
parts that take origin from the rhombencephalon 
and those that arise from the prosencephalon. 
The wall of the mesencephalon is completely 
converted into nerve-tissue, and forms the corpora 
quadrigemina, the two crura cerebri, and the aque- 
duct of Sylvius, which join the third ventricle with 
the fourth. 
The metencephalon gives origin to the cere- 
bellum and the pons Varolii. The cerebellum 
takes origin from a thickening of the superior 
wall of the vesicle, while the pons takes origin from a thickening of the lateral 
and inferior walls of the vesicle. 
The myelencephalon gives origin to the bulb or medulla oblongata, chiefly by a 
thickening of the lateral walls of the vesicle. The original hind-brain remains in 
the brain of the adult as the fourth ventricle. 
As already stated, these vesicles do not remain in the same plane. The formation 
of certain definite flexures alters the position of the vesicles with regard to one another 
(Fig. 554). The cephalic flexure is opposite the base of the mid-brain, which 
becomes sharply bent upon itself over the end of the notochord. This bending 
causes the mid-brain to become the most prominent part of the encephalon on the 
convexity of the curve. The pontine or pontal flexure is a curve in the hind-brain, 
in the opposite direction to that of the cephalic flexure. At the junction of the 
Fig. 552.-Plan showing the mode of 
formation of the ventricles of the brain 
and the central canal of the spinal cord. 
A. Prosencephalon. B. Thalamenceph- 
alon. C. Mesencephalon. D. Metenceph- 
alon. E. Myelencephalon. F. Central canal 
of cord. G. Lateral ventricle. H. Fora- 
men of Monro. (After Gerrish.) 860 
THE NERVOUS SYSTEM 
hind-brain with the spinal cord is the cervical or nuchal flexure. In the develop- 
ment of the brain the cephalic flexure remains permanent, but the other two 
flexures completely disappear. 
The manner in which the different parts of the encephalon are formed from 
the walls of this greatly altered medullary canal will now be considered, it being 
remembered that the ventricles are developed, as previously described, from the 
five secondary vesicles. 
The first vesicle, or prosencephalon, sends out two hollow protrusions, which 
spread rapidly, and in the walls of these nervous matter is developed, which con- 
stitutes the cerebral hemispheres (Fig. 554, H), the cavities remaining as the 
lateral ventricles. As these hemispheres extend they grow forward in front of 
the anterior extremity of the primitive brain, and lie side by side, separated by the 
longitudinal fissure; they also grow upward, and again lying side by side are 
separated by another portion of the same fissure, containing a thin layer of meso- 
blast, which forms the falx cerebri; behind and laterally they overlap the roof 
and sides of the other cerebral vesicles, so that by the seventh month they project 
Fig. 553.-Vertical section of the head in early embryos of the rabbit. Magnified. A. From an embryo five 
millimetres long. B. From an embryo six millimetres long. C. Vertical section of the anterior end of the 
notochord and pituitary body, etc., from an embryo sixteen millimetres long. In A, the faucial opening is still 
closed. In B, it is formed. C. Anterior cerebral vesicle, me. Mesocerebrum, mo. Medulla oblongata, co. 
Corneous layer, m. Medullary layer, if Infundibulum. am. Amnion, spe. Spheno-ethinoidal, 6c, central 
(dorsum sellae), and sp.o, spheno-occipital parts of the basis-cranii. h. Heart, f. Anterior extremity of primi- 
tive alimentary canal and opening (later) of the fauces, i. Cephalic portion of primitive intestine, tha. Thalamus. 
p'. Closed opening or the involuted part of the pituitary body (.py) ch. Notochord, ph. Pharynx. (From 
Mihalkovics.) 
behind them In the floor of each of these hemispheres there occurs a local 
thickening, which forms the corpus striatum, which is continuous behind with the 
optic thalamus presently to be described. The surface of the hemisphere is at 
first smooth, but about the fifth month a sulcus or groove appears in either hemi- 
sphere just external to the corpus striatum; this is the fissure of Sylvius: subse- 
quently other fissures appear on the surface, three of which are of sufficient depth 
to cause a projection into the lateral ventricle. These are the hippocampal fissure, 
corresponding to the hippocampus major of the lateral ventricle, the collateral 
fissure, corresponding with the bend of the posterior horn of the ventricle; and 
the calcarine fissure, corresponding with the projection of the calcar avis. 
The remainder of the first vesicle and the second, as we have seen, form the 
third ventricle, in its normal walls a thickening takes place, which forms the 
optic thalamus. From the floor of this ventricle a hollow protrusion passes down- 
ward, and is intimately connected with a diverticulum from the stomodaeum, to 
form part of the pituitary body (hypophysis cerebri) (Figs 553, 554, and 555). The 
greater part of the roof of the third ventricle is very thin, and with the pia mater THE B11A1N 
861 
Fig. 554.-Profile views of the brain of human embryos at three several stages, reconstructed from sections. 
(Copied from Quain's Anatomy.) A. Brain of an embryo of about fifteen days, magnified 35 diameters. B. 
Brain of an embryo about three and a half weeks old. The optic vesicle has been cut away. C. Brain of 
an embryo about seven and a half weeks old. The optic stalk is cut through. A. Optic vesicle. H. Vesicle of 
cerebral hemisphere, first secondary vesicle. Z. Thalamencephalon, second secondary vesicle. M. Mid-brain. 
J. Isthmus between mid-brain and hind-brain. Hh. Fourth secondary vesicle. N. Fifth secondary vesicle. Gb. 
Otic vesicle. Rf. Fourth ventricle. NK. Neck curvature. Br. Pons curvature. Pm. Mammillary process. 
Tr. Infundibulum. Up. (in B). Outline of hypophysis-fold of buccal epiblast. RI. Olfactory fold. In C the 
basilar artery is represented along its whole course. (His.) 862 
THE NERVOUS SYSTEM 
forms the velum interpositum; from its posterior part an outgrowth of cells forms 
the pineal body {epiphysis cerebri). Where the cerebral hemispheres are not 
separated in the middle line by the falx, in front and for some distance backward 
over the roof of the third ventricle their mesial surfaces come in contact, and to a 
certain extent fuse together, leaving, however, a small portion where no union 
takes place, and thus a slit-like cavity is left; this is termed the fifth ventricle, 
though it will be at once seen that its development is quite different from that 
of the other ventricles. Its lateral walls form the septum lucidum. The roof of 
this cavity becomes thickened, and nerve-fibres pass across from the one hemi- 
sphere to the other to form the corpus callosum, while in its floor longitudinal fibres 
are developed to form the fornix. 
The third vesicle, the cavity of which forms the iter a tertio ad quartum ven- 
triculum, develops in its roof four well-marked thickenings, which together form 
Optic thalamus. 
Posterior commissure. 
Foramen of Monro. 
'Pineal body. 
Crus cerebri. 
Aqueduct of Sylvius. 
Corpora quadrigemina. 
Cerebellum. 
~IV. Ventricle. 
Cerebral hemisphere. 
Olfactory lobe or 
rhinencephalon. 
Pons. 
Medulla ' 
oblongata. 
Lamina cinerea. 
Optic nerve. 
Corpus 
albicans. 
Spinal cord. 
Optic commissure. 
Pituitary body. 
Infundibulum. 
Fig. 555.-Median section of brain of human foetus during the third month. (After His.) 
the corpora quadrigemina, while its lateral regions become thickened to form the 
crura cerebri (Fig. 555). 
The dorsal surface of the fourth vesicle forms the covering of the fourth ventricle, 
and in it a thickening occurs which is developed into the cerebellum; its ventral 
and lateral regions form the pons (Fig. 555). 
In the fifth vesicle the lateral parts increase and grow downward on each side 
toward the middle line, forming the medulla, while the dorsal surface assists in 
forming the roof of the fourth ventricle. 
On making a transverse section of the lower part of the fourth ventricle, the 
alar and basal laminae, already referred to as being present in the cord,are readily 
recognized, while the thin roof-plate is seen to be greatly expanded laterally. 
The dorsal part of the alar lamina becomes folded outward and downward, form- THE BRAIN 
863 
ing what is termed the rhomboid lip (Fig. 556). This is at first separated by a 
groove from the lateral aspect of the alar lamina, but ultimately fuses with it. As 
the central canal of the cord opens out to form the fourth ventricle, the alar and 
basal laminae come to occupy the floor of the ventricle-the basal lamina lying 
nearest the mesial plane. 
Roof. 
Alar lamina.- 
Rhomboid 
lip. 
Basal lamina. 
Tractus 
solitarius. 
.Vagus nerve. 
Raphe. 
Hypoglossal 
nerve. 
Fig. 556.-Transverse section of medulla oblongata of human embryo. (After His.) 
The Communications of the Parts of the Brain,-In the posterior fossa of the 
cranium lies the medulla oblongata, the pons Varolii, and the cerebellum, and 
between these structures and the cerebrum is the tentorium cerebelli. The pons, 
medulla, and cerebellum surround the fourth ventricle. The greater portion of 
the fibres of the medulla are continued into the pons, but some fibres from the 
dorsal aspect of the medulla (the restiform bodies) pass into the cerebellum and 
-Mesencephalon 
•Superior cerebellar peduncle 
Middle cerebellar peduncle 
Inferior cerebellar peduncle 
Fig. 557.-Scheme showing the connections of the several parts of the brain. (Cunningham.) 
become the inferior cerebellar peduncles (Fig. 557). On each side of the pons a 
thick strand of transverse fibres passes to the cerebellum. These strands are the 
middle cerebellar peduncles (Fig. 557). 
The cerebral hemispheres are joined together by the corpus callosum, a com- 
missure lying within the depths of the great longitudinal fissure. Between and 
beneath the cerebral hemispheres is the inter-brain (thalamencephalcn), composed 
chiefly of the optic thalami. In the interior of each hemisphere is a space called 864 
THE NERVOUS SYSTEM 
the lateral ventricle. Between the optic thalami is the third ventricle. The foramen 
of Monro connects the third ventricle with the lateral ventricles. 
The mid-brain connects the cerebrum with the pons, medulla, and cerebellum. 
It is composed of the crura cerebri, which join together the pons and the cere- 
brum; the corpora quadrigemina, and the superior cerebellar peduncles (Fig. 557), 
which connect together the cerebrum and the cerebellum. In the mid-brain the 
aqueduct of Sylvius joins the third ventricle and the fourth ventricle. 
General Considerations and Divisions.-For the purposes of description the 
brain may be divided into five parts, as follows: (1) the two cerebral hemispheres; 
(2) the inter-brain {thalamencephalon}; (3) the mid-brain {mesencephalon}; the hind- 
brain {rhombencephalon}, which includes (4) the pons Varolii and cerebellum; and 
(5) the medulla oblongata. If the student will refer to the section on the Development 
of the Brain he will find that these five portions correspond fairly accurately to 
the five secondary cerebral vesicles, of which the brain at an early period of em- 
bryonal life consisted; the prosencephalon, or first vesicle, by means of a protrusion 
from its front part on either side, forms the cerebral hemispheres and the lateral 
ventricles; the remainder of the prosencephalon, together with the second vesicle, 
the thalamencephalon, form the inter-brain and third ventricle; the third vesicle, 
the mesencephalon, forms the mid-brain, or that portion which connects the inter- 
brain and hemispheres above with the pons Varolii below, and the cavity of the 
vesicle forms the aqueduct of Sylvius, or iter a tertio ad quartum ventriculum; the 
fourth vesicle, the metencephalon, becomes the future pons Varolii and cerebellum, 
and its cavity forms the upper half of the fourth ventricle; and, finally, the fifth 
vesicle, the myelencephalon, develops into the medulla oblongata, and its cavity 
forms the lower half of the fourth ventricle. It will thus be seen that the five 
divisions of the encephalon mentioned above correspond to the five secondary cere- 
bral vesicles, with the exception of the first two, which together form the cerebral 
hemispheres and the inter-brain. In consequence of this these two portions of 
the brain are sometimes grouped together as the cerebrum. 
I. The Hemispheres of the Cerebrum (Hemisphaeria Cerebri). 
General Considerations.-The two hemispheres constitute the largest portion 
of the encephalon, and, together with the parts derived from the inter-brain 
{thalamencephalon} form what is called by some writers the fore-brain {pros- 
encephalon}. They occupy the whole of the vault of the skull, and consist of a 
central cavity, in either hemisphere, surrounded by exceedingly thick and con- 
voluted walls of nervous tissue. The under surface or base of the cerebrum is 
of an irregular form, resting in front on the anterior and middle fossae of the 
skull and behind upon the tentorium cerebelli. The upper surface is of an 
ovoid form, broader behind than in front and convex in general outline. The 
frontal pole {polus frontalis} is the most prominent portion of the anterior end 
of the hemisphere. The most prominent portion of the posterior end is the 
occipital pole {polus occipitalis}. The most prominent part of the temporal 
lobe below the fissure of Sylvius is the temporal pole {polus temporalis}. The 
upper surface is divided into two lateral halves or hemispheres, the right and 
left, by the great longitudinal fissure {fissura longitudinalis cerebri}, which extends 
throughout the entire length of the cerebrum in the middle line, reaching down 
to the base of the brain in front and behind, but interrupted in the middle 
by a broad transverse commissure of white matter, the corpus callosum, which 
connects the two hemispheres together. 
The Constituent Parts of the Hemisphere.-The hemisphere is composed 
of three distinct parts: the brain-mantle (palliumi}, the chief mass of the hemi- 
sphere; the olfactory brain or lobe {rhinencephalon}, composed of the olfactory THE HEMISPHERES OF THE CEREBRUM 
865 
bull), anterior perforated space, a portion of the uncinate gyrus, the hippocampus, 
the septum lucidum, etc., and the corpus striatum. 
The Surface of the Cerebrum.-Each hemisphere presents an outer convex 
surface (facies convexa cerebri), filling the concavity of the corresponding half of 
the vault of the cranium; an inner, flattened surface facies medialis cerebri), which 
is vertical and directed toward the corresponding surface of the opposite hemi- 
sphere (the two inner surfaces forming the sides of the longitudinal fissure); and an 
under surface or base (basis cerebri), of irregular form, which rests in front on the 
anterior and middle fossae of the base of the skull, and behind upon the tentorium 
cerebelli. The hemispheres are composed of an outer stratum of gray matter (sub- 
stantia grisea), called the cortical substance or the cerebral cortex, and in the inte- 
rior of a mass of white matter (substantia alba) called the medullary centre. The 
cortex is thrown into a number of creases or infoldings, which are termed 
fissures and sulci (sulci cerebri), and these separate the surface into a number 
of irregular eminences, named convolutions or gyri (gyri cerebri). 
The infoldings or creases are of two kinds, complete fissures and incomplete 
fissures or sulci. The complete fissures (fissurae) are of large size, and appear 
early in foetal life; they are few in number, nearly constant in their arrangement, 
and are produced by infoldings of the entire thickness of the wall of the cerebrum, 
producing corresponding elevations in the interior of the ventricle, and hence are 
termed complete fissures. They comprise (a) the hippocampal or dentate fissure; 
(b) the anterior part of the calcarine fissure; (c) the collateral fissure. The sulci are 
vastly more numerous than the complete fissures; they are superficial depressions 
of the gray matter, which is folded inward and only indents the central white 
substance. They produce no corresponding elevations in the interior of the 
ventricle, and are therefore spoken of as incomplete fissures. They are fairly con- 
stant in their arrangement, and have received names indicative of their position 
and direction, but at the same time vary, within certain limits, in different indi- 
viduals. They are similar, without being absolutely identical, on the two sides of 
the brain. It therefore follows that the gyri or convolutions (gyri cerebri) which 
lie between these sulci are fairly constant in their general arrangement. The 
gyri upon the surface are called superficial gyri. Within the sulci, adjacent super- 
ficial gyri are joined by deep gyri (gyri profundi). Short gyri, superficial or deep 
which connect two gyri of greater length are called annectant or transitional 
gyri (gyri transitivi). 
The number and extent of the convolutions, as well as the depth of the inter- 
vening sulci, appear to bear a close relation to the intellectual power of the indi- 
vidual, as is shown in their increasing complexity of arrangement as one ascends 
from the lowest mammalia up to man, where they present a most complex arrange- 
ment. Again, in the child, at birth, before the intellectual faculties are exercised, 
the convolutions are simpler, and the sulci between them shallower, than in the 
adult. In old age, when the mental faculties have diminished in activity, the 
gyri and sulci become less prominently marked. By their arrangement the con- 
volutions are adapted to increase the amount of gray matter without occupying 
much additional space, while they also afford a greater extent of surface for the 
termination of white fibres in gray matter. 
It will be convenient in the first instance to describe the fissure which sepa- 
rates the two hemispheres from each other, and those which divide each hemisphere 
into its larger divisions. 
Fissures and Sulci of the Outer Surface of the Hemispheres. The Longitu- 
dinal Fissure (fissura longitudinalis cerebri) (Fig. 560).-This great fissure separates 
the cerebrum into two hemispheres, and reaches from the front to the back of the 
organ; it contains a vertical process of the dura mater, the falx cerebri (p. 849). In 
front and behind the longitudinal fissure extends from the top (dorsal surface) to 866 
THE NERVOUS SYSTEM 
the bottom (ventral surface) of the cerebrum, and completely separates the two 
hemispheres, but its middle portion only separates the hemispheres for about 
half their vertical extent, the floor of this part of the fissure being formed by the 
great central white commissure, the corpus callosum (Figs. 567 and 571), which 
connects the two hemispheres together. 
The remaining fissures are situated in one or other of the two hemispheres, with 
the exception of the transverse fissure, one-half of which is contained in each 
hemisphere. 
Sylvian Fissure (fissura cerebri lateralis [Sylvii]) (Figs. 558, 561, 565, and 570). 
-This fissure is a well-marked cleft on the base and side of the hemisphere. 
Starting at the base of the brain in a depression, the vallecula Sylvii, in which is 
situated the anterior perforated space (Fig. 570). The fissure passes outward 
between the frontal and temporal lobes, along the lesser wing of the sphenoid 
Parieto- 
'occipital 
Sulcus. 
Frontal Lobe 
Parietal Lobe 
Occipital 
Lobe 
Temporal Lobe 
Fig. 558.-Chief fissures and lobes on the external surface of the cerebral hemispheres. 
bone to the external surface of the hemisphere. The point at which it reaches 
the external surface is called the Sylvian point. It here gives off a short anterior 
horizontal limb (ramus anterior horizontalis}, which passes forward, and a short 
ascending or vertical limb (ramus anterior ascendens}, which passes upward into 
the inferior frontal convolution. It also gives off the posterior horizontal limb 
(ramus posterior}, which is the most distinct of the three branches. The posterior 
horizontal limb lies under the middle third of the lateral surface of the hemisphere 
and above the temporal lobe. It passes backward and slightly upward for about 
two and a half inches and terminates by an upward inflexion in the parietal lobe, 
which is called the ascending terminal portion. The anterior horizontal and the 
vertical limbs are separated by the frontal operculum (pars triangularis}, which is the 
foot of the inferior frontal convolution. A portion of the same convolution below 
the anterior limb is calle 1 the orbital operculum (pars orbitalis}. Between the vertical 
and posterior horizontal limbs is the fronto-parietal operculum (pars opercular is}. THE HEMISPHERES OF THE CEREBRUM 
867 
Limiting Sulcus of Reil (sulcus circularis Reili) (Fig. 566).-If the lips of the 
posterior horizontal limb of the Sylvian fissure are widely separated, the island of 
Reil (insula) (Figs. 566 and 568) is seen in the depths, surrounded by the limiting 
sulcus. The upper or external portion of the sulcus separates the island from 
the parietal and frontal lobes, the lower or posterior portion from the temporal 
lobe, and the anterior portion from the frontal lobe. 
The Central Sulcus of Rolando or the Fissure of Rolando (sulcus centralis 
[Rolandi]) (Figs. 558, 559, 561, 565, and 574).-The fissure of Rolando is situ- 
ated about the middle of the outer surface of the hemisphere, and, coursing 
obliquely downward and forward, divides the surface of the hemisphere into 
approximately equal parts. It is between the frontal and parietal lobes. It com- 
mences as a rule on the mesial surface of the longitudinal fissure, runs forward 
a short distance, and ascends to the superior mesial border, which it reaches a 
little behind its mid-point, that is at a point half an inch behind the middle of a 
line drawn from the nasal eminence to the external occipital protuberance. It 
then runs sinuously downward and forward, to terminate a little above the hori- 
INTERLOCKING 
'GYRI 
ASCENDING 
.FRONTAL 
| CONVOLUTION 
ASCENDING 
PARIETAL 
CONVOLUTION 
Fig. 559.-Sulcus of Rolando fully opened up, so as to exhibit the interlocking gyri and deep annectant 
gyrus behind it. (Cunningham.) 
zontal limb of the fissure of Sylvius, and about half an inch behind the ascend- 
ing limb of the same fissure. The angle made by the fissure of Rolando and the 
mesial plane is known as the Rolandic angle, and it varies in the adult between 
69 degrees and 74 degrees (Cunningham). It forms two chief curves: the upper 
or superior curve or genu is concave forward and upward, while the lower or 
inferior curve or genu has its concavity directed backward. If the lips of the 
Rolandic fissure are opened, we will see in the depths frontal gyri interlocked 
with parietal gyri (Fig. 559). Two of these gyri are often fused, and this fused 
gyrus is named the deep annectant gyrus (Fig. 559). 
The Parieto-occipital Sulcus (sulcus occipitoparietalis) (Figs. 558, 562, 564, and 
565).-The parieto-occipital sulcus is only seen to a slight extent on the outer 
surface of the hemisphere, being situated for the most part on its mesial aspect. 
The portion on the outer surface is called the external parieto-occipital sulcus, 
to distinguish it from the part continued on to the internal surface, which is 
termed the internal parieto-occipital sulcus. The external parieto-occipital sulcus 
commences about midway between the posterior extremity or occipital pole of 
the brain and the central sulcus of Rolando, and runs downward and outward for 
about half an inch, and is ended by an arch-shaped convolution (arcus parieto- 868 
THE NERVOUS SYSTEM 
occipitalis). The internal parieto-occipital sulcus is vertical in direction, is very 
distinct, and passes into the calcarine fissure. When its lips are fully separated, 
deep annectant gyri come into view. 
Besides the three fissures which have been discussed, the following must be 
mentioned (the situation of each is shown in Fig. 561). On the outer surface 
of the hemisphere there are the three frontal sulci, the sulcus frontalis superior, 
medius, and inferior. The sulcus paramedialis, the superior and inferior precentral 
sulci, sulcus diagonalis, the superior and inferior temporal sulci, the superior and 
inferior post central sulci, the ramus occipitalis, the sulcus occipitalis transversus, 
OCCIPITAL 
POLE 
LONGITUDI NAL 
FISSURE 
FRONTAL 
POLE 
LONGITUDINAL 
FISSURE 
Fig. 560.-The cerebral hemispheres viewed from above. (Spalteholz.) 
the ramus horizontalis, the calloso-marginal sulcus, the inferior transverse furrow 
(Fig. 561). The sulcus interparietalis (of Turner) is a group of four sulci: the 
sulcus post-centralis inferior, the sulcus post-centralis superior, the ramus horizontalis, 
and the ramus occipitalis. The first two are usually joined; the last two remain 
distinct and separate. When the lips of the intraparietal sulcus are widely 
opened, deep annectant gyri come into view. 
The fissures of Sylvius, of Rolando, and the parieto-occipital sulcus divide 
the external surface of the hemisphere into four lobes: the frontal, the parietal, the 
occipital, and the temporal lobes. To these must be added (1) the central lobe or 
island of Reil, which is situated deeply in the Sylvian fissure, and (2) the olfactory THE HEMISPHERES OF THE CEREBRUM 
869 
lobe, which is found at the base of the brain and was formerly described under the 
name of the olfactory nerve. 
The Lobes on the External Surface.-The lobes on the external surface have 
received their names from the bones of the skull with which they are most nearly 
in relation, but it must be borne in mind that they do not correspond in shape or 
limit with the bone after which they are named. The division is, moreover, to a 
certain extent artificial, as will be seen from the following description. If a line 
is drawn in continuation of the external oarieto-occipital sulcus downward and 
outward to the lower border of the hemisphere, it will impinge on a slight notch, 
the pre-occipital notch, and if a second line is prolonged backward from the hori- 
zontal part of the fissure of Sylvius to join the first line, the division of the outer 
surface of the hemisphere into four lobes will be accomplished (Fig. 558). The 
portion in front of the central sulcus of Rolando is the frontal lobe; that behind the 
central sulcus of Rolando and above the fissure of Sylvius is the parietal lobe; the 
Fig. 561.-Gyri and sulci on the outer surface of the cerebral hemisphere, p, sulcus frontalis superior; 
f2, sulcus frontalis inferior; f.m., sulcus frontalis medius; p.m., sulcus paramedialis; A, pars basilaris; B, pars 
triangularis; C, pars orbitalis; S, Sylvian fissure; s1, anterior horizontal limb (Sylvian fissure); s2, ascending 
limb (Sylvian fissure); s3, posterior horizontal limb (Sylvian fissure); p.c.i., inferior precentral sulcus; p.c.s., 
superior precentral sulcus; r, fissure of Rolando; g.s., superior genu; g.i., inferior genu; d, sulcus diagonals; 
tl, superior temporal sulcus (parallel); t-, inferior temporal sulcus; p1, inferior post-central sulcus; p2, superior 
post-central sulcus; p3, ramus horizontalis; p4, ramus occipitalis; s.o.t., sulcus occipitalis transversus; c.m., 
•calloso-marginal sulcus; c.t.r., inferior transverse furrow. (Cunningham). 
portion behind the parieto-occipital sulcus and its imaginary line of continuation 
to the pre-occipital notch is the occipital lobe; and the part below the fissure of 
Sylvius and in front of the occipital lobe is the temporal lobe. 
The Fissures, Sulci, and Lobes of the Mesial and Tentorial Surfaces.-The 
mesial surface of the cerebrum can only be fully viewed by dividing the corpus 
callosum and the structures beneath it longitudinally in the middle line; in order 
to expose the tentorial surface, the pons Varolii, cerebellum, and medulla must 
be removed, by division of the crus cerebri on either side. The diagram (Fig. 562) 
and the section (Fig. 564) show these fissures and sulci. The parts in the centre, 
below the corpus callosum, belong to the interior of the brain, and will be disre- 
garded for the present, while the lobes and fissures of the remaining portion of the 
hemisphere are considered. The fissures and sulci are ten in number on each side, 
in addition to a small part of the fissure of Sylvius, the commencement of which 
is seen separating the frontal and temporal lobes and the beginning and end of 
the great longitudinal fissure. These fissures and sulci are named the olfactory 870 
THE NERVOUS SYSTEM 
sulci, the orbital sulci, the inferior and middle temporal sulci, the occipito-temporal 
sulci, the calloso-marginal and the internal parieto-occipital sulci, the calcarine, the 
collateral, and the dentate or hippocampal fissures. 
The Olfactory Sulcus (sulcus oljactor ius) (Figs. 563 and 566).-The olfactory 
sulcus is a straight furrow which lodges the olfactory tract and bulb. 
The Orbital Sulcus (sulcus orbitalis) (Figs. 563 and 566).-The orbital sulcus is 
usually shaped somewhat like the letter H, and is then composed of an external 
limb (sulcus orbitalis externus), an internal limb (sulcus orbitalis internus), and 
a transverse portion (sulcus orbitalis transversus). The parts of the orbital sulcus 
are often complicated and irregular, and are sulci rather than parts of a sulcus. 
The Inferior Temporal Sulcus (sulcus temporalis inferior).-The inferior temporal 
sulcus is shown in Fig. 563. 
The Occipito-temporal Sulcus (Fig. 563).-The occipito-temporal sulcus is in 
the tentorial base of the occipital lobe. It is external to the collateral fissure, is 
not limited purely to the temporal lobe, and bounds the occipito-temporal gyrus 
externally. It often consists of two or more portions. 
Fig. 562.-The gyri and sulci on the mesial aspect of the cerebral hemisphere: r, fissure of Rolando; 
r.o., rostral sulcus; i.t., incisura temporalis. (Cunningham.) 
The Calio so-marginal Sulcus (sulcus cingulum) (Figs. 562, 564, and 567).-The 
calloso-marginal sulcus commences below the anterior extremity of the corpus 
callosum; it at first runs forward and upward, parallel with the rostrum of 
the corpus callosum, and, winding round in front of the genu of that body, it 
co'ntinues from before backward, between the upper margin of the hemisphere 
and the convolution of the corpus callosum, to about midway between the ante- 
rior and posterior extremities of the brain, where it ascends to reach the upper 
margin of the hemisphere, a short distance behind the superior extremity of the 
fissure of Rolando. 
The Internal Parieto-occipital Sulcus (sulcus parietooccipitalis) (Figs. 562, 564, 
and 567).-The internal parieto-occipital sulcus extends in an oblique direction 
downward and forward to join the calcarine fissure, on a level with the hinder 
end of the corpus callosum. 
The Calcarine Fissure (fissura calcarina) (Figs. 562, 564, and 567).-The cal- 
carine fissure commences, usually by two branches, close to the posterior extremity 
of the hemisphere. 'These soon unite, and the fissure runs nearly horizontally for- 
ward, and is joined by the parieto-occipital fissure, and continues as far as the THE HEMISPHERES OF THE CEREBRUM 
871 
posterior extremity of the corpus callosum, a little below the level of which it 
terminates in the limbic lobe. Its anterior part causes the prominence in the 
interior of the brain known as the hippocampus minor or calcar avis. 
The Collateral Fissure (fissura collateralis) (Figs. 562, 563, 564, and 567).-The 
collateral fissure is situated on the tentorial surface, below and external to the 
preceding, being separated from it by the subcollateral or uncinate gyrus. It runs 
forward, from the posterior extremity of the brain, nearly as far as the tip of the 
temporal lobe. It lies below the posterior and descending horns of the lateral 
ventricle, and its middle part causes the prominence in the interior of the brain 
known as the eminentia collateralis. 
The Dentate or Hippocampal Fissure (fissura hippocampi) (Figs. 563, 564, and 
567).-The dentate or hippocampal fissure commences immediately behind 
Fig. 563.-Gyri and sulci on the tentorial and orbital aspects of the cerebral hemisphere. (Cunningham.) 
the posterior extremity of the corpus callosum, and runs forward to terminate 
at the recurved part of the hippocampal gyrus. It causes the prominence of the 
hippocampus major in the descending horn of the lateral ventricle. 
In addition to these fissures, which are constant, there is frequently an irregular 
broken fissure, which is sometimes an independent sulcus, but which often appears 
to be a continuation backward of the posterior part of the calloso-m argin al 
fissure, before it ascends to reach the upper edge of the hemisphere. This 
has been termed the post-limbic fissure (Fig. 562). The fissures of the internal 
and tentorial surfaces map off portions of the hemisphere, which form parts 
of the lobes found on the external surfaces. That portion which lies in front and 
above the calloso-marginal fissure belongs almost entirely to the frontal lobe; its 
posterior extremity, which extends for a short distance behind the upper end of the 872 
THE NEU VO US SYSTEM 
fissure of Rolando, forms a small part of the parietal lobe; that portion which lies 
above the internal parieto-occipital fissure and behind the calloso-marginal fissure 
forms apart of the parietal lobe; that between the parietooccipital fissure above 
and the calcarine fissure below is a portion of the occipital lobe; and all the region 
below the calcarine fissure behind and the collateral fissure in front belongs to 
the temporal lobe. The remainder of the mesial and tentorial surfaces of the 
hemisphere constitute what Broca termed the limbic lobe, which is subsequently 
referred to (p. 878). 
The surface of the hemisphere has thus been divided by large sulci and 
fissures into its different parts-viz., the frontal, the parietal, the occipital, the 
temporal, the limbic, the olfactory lobes, and the island of Reil. Each of these 
lobes is further subdivided into convolutions or gyri by smaller fissures, which, 
though less constant in their arrangement than the larger fissures, have a fairly 
definite course. 
1. The Frontal Lobe (lobus frontalis) (Figs. 558,561,562,563,564,565, and 566). 
-It is the largest of the lobes of the cerebrum. Its outer surface is bounded behind 
Frontal Lobe 
Parietal 
v Lo b e 
Op tic 
Thalamus 
Occipital' 
Lobe . 
Fig. 564.-Fissures and lobes on the internal surface of the cerebral hemispheres. 
by the central sulcus of Rolando and below by the posterior horizontal limb of 
the fissure of Sylvius. On the orbital surface the fissure of Sylvius bounds it 
posteriorly. On the mesial surface it is bounded by the calloso-marginal sulcus. 
External Surface.-On its external surface the frontal lobe presents three sulci 
and four gyri or convolutions. The sulci are the precentral, the superior frontal, 
and the inferior frontal. 
The Precentral Sulcus (sulcus praecentralis) is divided into two parts: The 
inferior precentral sulcus (sulcus praecentralis inferior) is composed of two parts 
(Figs. 561 and 565): one part (the vertical) is placed before the Rolandic fissure; 
the other part (the horizontal) passes upward and to the front into the middle 
frontal convolution. The superior precentral sulcus (sulcus praecentralis superior) 
is vertical in direction and is placed in front of the upper part of the Rolandic 
fissure. The other frontal sulci are shown in the diagrams. 
The ascending frontal convolution or praecentral gyrus (gyrus centralis anterior or 
gyrus frontalis ascendens) (Figs. 561 and 565), one of the chief motor areas of the THE HEMISPHERES OF THE CEREBRUM 
873 
cortex, is a simple convolution, and is limited in front by the precentral sulcus and 
behind by the fissure of Rolando. It extends from the upper margin of the hemi- 
sphere above to a little behind the bifurcation of the fissure of Sylvius below. From 
it two sulci, the superior and inferior frontal sulci {sulcus frontalis superior and sulcus 
frontalis inferior), run forward and downward, and divide the remainder of the 
outer surface of the lobe into three parallel principal convolutions, named respect- 
ively the superior, middle, and inferior frontal convolutions (Figs. 561 and 565). 
'The superior or first frontal convolution {gyrus frontalis superior) (Figs. 561 and 
565) is situated between the margin of the longitudinal fissure and the superior 
frontal sulcus. It extends above on to the inner aspect of the hemisphere, forming 
the greater part of the marginal convolution (Figs. 562, 564, and 567), and in front 
on to the orbital surface, forming the internal orbital convolution (Figs. 563 and 
End of calloso- 
marginal fissure. 
Parieto- 
occipital 
fissure. 
Ascending fissure 
of Sylvius. 
Fissure 
of Sylvius. 
Fig. 565.-Convolutions and sulci on the external surface of the cerebral hemisphere. 
566). It is usually more or less completely subdivided into two (pars superior 
and pars inferior) by several depressions of trivial length, the aggregation being 
called by Cunningham the sulcus paramedialis. It is frequently interrupted and 
broken into several parts by bridging convolutions. 
The second or middle frontal convolution (gyrus frontalis medius) (Figs. 561 and 
565) is situated between the superior and inferior frontal sulci, and extends from 
the precentral sulcus on to the orbital surface of the lobe, where it forms the 
anterior orbital convolution (Figs. 563 and 566). The middle frontal convolution 
is frequently subdivided into two (pars superior and pars inferior) by a sagittally 
directed sulcus, the sulcus frontalis medius of Eberstaller. 
The third or inferior frontal convolution (gyrusfrontalis inferior) (Figs. 561 and 565) 
is situated belowtheinferior frontal sulcus, and extends forward from the lower part 
of the precentral sulcus, on to the under surface of the lobe, where it forms the pos- 874 
THE NERVOUS SYSTEM 
terior orbital convolutions (Figs. 563 and 566). The inferior frontal convolution is 
subdivided by the anterior and ascending limbs of the fissure of Sylvius into three 
parts-viz.: (1) anterior part or the orbital operculum (pars orbitalis), below the ante- 
rior limb of the fissure of Sylvius; (2) middle part or "cap" of Broca or the frontal 
operculum (pars triangularis), between the anterior horizontal and the vertical limbs 
of the fissure of Sylvius; and (3) posterior part or the fronto-parietal operculum (pars 
basilaris), behind the posterior horizontal and vertical limbs of the fissure of Sylvius. 
In the basilar part is the sulcus diagonals (d in Fig. 561). The left inferior frontal 
convolution is, as a rule, more highly developed than the right, and is named the 
convolution of Broca, from the fact that in 1861 Broca declared that it was the centre 
for speech. It is now known that the region of speech comprises the posterior part 
of the inferior frontal convolution and the fronto-parietal operculum. 
GYRUS 
RECTUS 
ANTERIOR 
PERFORATED 
SPACE 
Fig. 566.-Convolutions and sulci on the under surface of the anterior lobe. 
Under Surface (Figs. 563 and 566).-The undersurface of the frontal lobe rests 
on the orbital plate of the frontal bone, and is sometimes named the orbital lobe. 
It is divided into three convolutions by a well-marked sulcus, the orbital or 
tri-radiate sulcus (sulci orbitales). These convolutions are named, from their 
position, the internal, anterior, and posterior orbital convolutions, and are the con- 
tinuations respectively of the superior, middle, and inferior frontal convolutions 
of the external surface. The internal orbital convolution presents a well-marked 
antero-posterior groove or sulcus, the olfactory sulcus (sulcus oljactorius), for 
the olfactory bulb and tract; and the portion internal to this is named the gyrus 
rectus, and is continuous with the marginal gyrus, presently to be described. 
Mesial or Internal Surface (Figs. 562 and 567).-The mesial or internal surface 
of the frontal lobe is occupied by a single curved convolution, which from its THE HEMISPHERES OE THE CEREBRUM 
875 
situation is termed the marginal gyrus (gyrus marginal is). It commences in front 
of the anterior perforated space, runs along the margin of the longitudinal fissure 
on the mesial surface of the orbital lobe, where it is continuous with the internal 
orbital convolution; it then ascends, and runs backward to the point where the 
calloso-marginal fissure turns upward to reach the superior border of the hemi- 
sphere. An oval portion at the posterior part of this convolution is sometimes 
marked off by a vertical fissure, and is distinguished as the paracentral lobule 
(lobulus paracentralis), because it is continuous with the convolutions in front and 
behind the central fissure or fissure of Rolando. In the anterior portion of the 
marginal gyrus are two sulci named the sulci rostrales. 
2. The Parietal Lobe (lobus parietalis) (Figs. 558,561,562,564,565, and 567).- 
This lobe includes a considerable portion of the surface of the hemisphere, 
Fig. 567.-Convolutions and sulci on the internal surface of the cerebral hemispheres. 
and it also occupies the portion of the mesial surface known as the quadrate 
lobule or cuneus. It is bounded in front by the central sulcus of Rolando. 
Posteriorly it is partly separated from the occipital lobe by the external parieto- 
occipital sulcus. Below it is partly limited by the posterior horizontal limb of the 
fissure of Sylvius. 
External Surface.-On its external surface the parietal lobe presents for examina- 
tion one sulcus (which is divided into four parts) and three convolutions. 
The Intraparietal Sulcus of Turner (sulcus intra parietalis) (Figs. 561 and 565), 
according to Prof. Cunningham, is a group of four sulci-viz., the superior post- 
central sulcus (sulcus postcentralis superior), the inferior post-central sulcus (sulcus 
postcentralis inferior), the horizontal ramus (ramus horizontalis), and the occipital 
ramus (ramus occipitalis). The first named lies back of the upper portion of the 
central sulcus of Rolando; the second lies back of the lower portion of the same 
sulcus. In front of the post-central sulci is the ascending parietal (post-central) 
convolution (gyrus centralis posterior). The superior and inferior post-central sulci 
are usually continuous. The upper end of the inferior post-central sulcus is pro- 
longed upward and backward as the ramus horizontalis between the superior 
and inferior parietal gyri. The ramus occipitalis may or may not be joined to the 
ramus horizontalis. It is the external boundary of the arcus parieto-occipitalis. THE NERVOUS SYSTEM 
876 
The ascending parietal convolution or the post-central gyrus {gyrus ascendens parie- 
tails or gyrus postcentralis) (Figs. 561 and 565) is usually regarded as one of the 
chief motor areas of the cortex, although Mills, Sherrington and others are of the 
opinion that the motor areas are all in front of the central sulcus of Roland. The 
ascending parietal convolution is bounded in front by the central sulcusof Rolando, 
behind by the superior and inferior post-central sulci. It extends from the great lon- 
gitudinal fissure above to the posterior horizontal limbof the fissureof Sylvius below. 
It lies parallel with the ascending frontal convolution, with which it is connected 
below, and also, sometimes, above the termination of the central sulcus of Rolando. 
The superior parietal convolution {lobulus parietalis superior) (Figs. 561 and 565), 
still regarded by some as a part of the motor area of the cortex, is bounded in front 
by the superior post-central sulcus, which lies between it and the previous convolu- 
tion, but with which it is usually connected above the upper extremity of the sulcus; 
behind, it is joined to the occipital lobe by a narrow convolution, the first annectant 
gyrus {arcus parietooccipitalis); below, it is separated from the inferior parietal con- 
volution by the horizontal portion of the intraparietal sulcus; and above, it is 
continuous on the inner surface of the hemisphere with the quadrate lobe. 
The inferior parietal convolution {lobulus parietalis inferior) (Figs. 561 and 565) is 
that portion of the parietal lobe which is situated between the ascending portion of 
the intraparietal sulcus in front, the horizontal portion of the same sulcus above, the 
horizontal limb of the fissure of Sylvius below, and the posterior boundary of the 
parietal lobe behind. It is divided into three convolutions: the supramarginal, the 
angular, and the post-parietal. One, the supramarginal convolution {gyrus supra- 
marginalis), lies behind the ascending part of the intraparietal sulcus and above the 
horizontal limb of the fissure of Sylvius, over the extremity of which it arches. It is 
connected in front with the ascending parietal convolution below the intraparietal 
sulcus, and behind with the first or superior temporal convolution around the pos- 
terior extremity of the fissure of Sylvius (Fig. 561). The angular convolution or the 
angular gyrus {gyrus angularis) is united anteriorly with the foregoing, while pos- 
teriorly it is continuous with the middle or second temporal convolution by a process 
which curves around the superior temporal or parallel sulcus (Fig. 561). The 
post-parietal convolution or the second annectant gyrus passes around the posterior 
end of the middle temporal convolution and into the inferior temporal convolu- 
tion. It joins the inferior parietal convolution to the occipital lobe. 
The Internal or Mesial Surface (Figs. 562 and 564).-The internal or mesial surface 
of the parietal lobe is continuous with the external surface over the upper edge of 
the hemisphere. It is of small size, and forms one square-shaped convolution, 
which from its shape is termed the quadrate lobe. From its situation above the 
cuneate lobe it is named the precuneus (praecuneus). The post-limbic sulcus imper- 
fectly separates the precuneus from the limbic lobe. 
3. The Occipital Lobe {lobus occipitalis) (Figs. 558, 561, 562, 563, 564, 565, 
and 567).-The occipital lobe is indefinitely separated from the temporal and 
parietal lobes. It is defined by Cunningham as the portion of "the hemisphere 
which encloses the posterior horn of the lateral ventricle." In form it is pyram- 
idal, and it possesses an apex, the occipital pole {polus occipitalis), and three 
surfaces. The inferior surface is directly continuous with the temporal and 
limbic lobes. On the outer surface the external parieto-occipital fissure partly 
separates it from the parietal lobe. On the mesial surface the internal 
parieto-occipital fissure separates it from the precuneus. 
External Surface (Figs. 561 and 565) .-The occipital lobe is divided on its external 
surface into three convolutions by two indistinct sulci, the superior and middle occip- 
ital sulci {sulcus occipitalis transversus and sulcus occipitalis lateralis). They are 
directed backward across the lobe, being frequently small and ill marked; the supe- 
rior is sometimes continuous with the horizontal portion of the intraparietal sulcus. THE HEMISPHERES OE THE CEREBRUM 
877 
The superior occipital convolution {gyrus occipitalis superior) is situated above 
the superior sulcus, and is connected to the superior parietal convolution by the 
first annectant gyrus. 
The middle occipital convolution {gyrus occipitalis medius) is situated between 
the superior and middle occipital sulci, and is connected to the angular convolution 
by the second annectant gyrus, and to the middle temporal convolution by the 
third annectant gyrus. 
The inferior occipital convolution {gyrus occipitalis inferior) is situated below the 
middle occipital sulcus, and is sometimes separated from the external occipito- 
temporal convolution on the under surface of the hemisphere by an inconstant 
sulcus, the inferior occipital sulcus {sulcus occipitalis inferior). The inferior occipi- 
tal convolution is connected to the inferior temporal convolution by the fourth 
annectant gyrus. 
Internal or Mesial Surface (Figs. 562, 564, and 567).-The internal or mesial sur- 
face of the occipital lobe presents a triangular convolution, which is known as the 
cuneate lobule {cuneus). I is situated between the internal parieto-occipital sulcus 
and the calcarine fissure, which, as already mentioned, meet some distance behind 
the posterior extremity of the corpus callosum. 
The lingual gyrus or subcalcarine convolution {gyrus lingualis) is between the 
calcarine and collateral fissures, and runs forward into the hippocampal portion 
of the limbic lobe. A portion of the gyrus lingualis is on the mesial aspect and 
a portion on the inferior aspect of the occipital lobe (Fig. 563). 
Inferior Surface (Fig. 563).-The inferior or tentorial surface of the occipital lobe 
possesses one convolution, the occipito-temporal gyrus, which is continuous with 
the temporal lobe and the limbic lobe (p. 878), and is bounded externally by the 
occipito-temporal sulcus. 
The centre for visual memory is in the external surface of the occipital lobe 
and the angular gyrus. 
4. The Temporal Lobe (lobus temporalis) (Figs. 558, 561, 562, 563, 564, 565, 
and 567).-The temporal lobe is sometimes called the temporo-sphenoidal lobe. 
This lobe lies behind the junction point and below the posterior horizontal limb 
of the Sylvian fissure. On its inferior (tentorial) surface the collateral fissure 
separates it from the hippocampal portion of the limbic lobe. The apex of the 
temporal lobe projects in front of the Sylvian junction. The lobe presents an 
outer and an inferior surface. 
Outer Surface (Figs. 561 and 565).-The outer surface is subdivided by two 
sulci, named respectively the first and second temporal sulci. 
The First Temporal Sulcus {sulcus temporalis superior) is well marked, and runs 
from before backward through the temporal lobe parallel with, but some little 
distance below, the posterior horizontal limb of the fissure of Sylvius; hence it 
is often termed the parallel sulcus. 
The Second Temporal Sulcus {sulcus temporalis medius) takes the same direction 
as the first, but is situated at a lower level, and is often interrupted by one or more 
bridging convolutions. These two sulci subdivide this surface of the temporal lobe 
into three convolutions. 
The first or superior temporal convolution {gyrus temporalis superior) is situated 
between the posterior horizontal limb of the fissure of Sylvius and the first tem- 
poral sulcus, and is continuous behind with the supramarginal convolution. 
The second or middle temporal convolution {gyrus temporalis medius) lies between 
the first and second temporal sulci, and is continued behind into the angular and 
middle occipital convolutions. 
The third or inferior temporal convolution {gyrus temporalis inferior) is placed 
below the second temporal sulcus; it is connected posteriorly with the inferior 
occipital convolution, and is also prolonged on to the under or tentorial surface THE NERVOUS SYSTEM 
878 
of the temporal lobe (Fig. 563), where it is limited internally by the third tem- 
poral sulcus, about to be described. 
Inferior Surface (Fig. 563).-The inferior or tentorial surface presents two 
fissures-viz., the third temporal sulcus and the collateral fissure-the latter fissure 
has already been described (p. 871). 
The Third Temporal Sulcus (sulcus temporalis inferior) extends from near the 
occipital pole behind to near the anterior extremity of the temporal lobe in front, 
but is, however, frequently subdivided by bridging gyri. 
The convolution on the inferior surface is the fourth temporal or subcollateral 
or the occipito-temporal convolution. It is situated between the third temporal 
sulcus and the collateral fissure. 
5. The Central Lobe or Island of Reil (Insula) (Figs. 566, 568, 576, and 577). 
-The central lobe or island of Reil lies deeply in the Sylvian fissure, and can only 
be seen when the lips of that fissure are widely separated, since it is overlapped 
and hidden by the convolutions which bound the fissure. These convolutions are 
termed the opercula of the insula (opercula insulae) (operculum, a lid); they are 
separated from each other by the three limbs of the Sylvian fissure, and are 
named the orbital, frontal, fronto-parietal, and temporal opercula (p. 866). The insula 
Fig. 568.-The island of Reil. Left side. The overlapping parts of the hemisphere have been removed. 
1,2,3. Gyri breves. 4,5. Gyrus longus, bifurcated at its upper extremity. (Dalton.) 
is almost surrounded by a deep limiting sulcus, the limiting sulcus of Reil (sulcus 
circularis Reili) (Fig. 566 and p. 867), which separates it from the frontal, parietal, 
and temporal lobes. When theopercula huve been removed, the insula presents the 
form of a triangular eminence; its apex is directed downward and inward toward 
the anterior perforated space, and is continuous in front with the posterior 
orbital convolution. At the apex of the insula the limiting sulcus does not exist, 
and the gray matter passes into the anterior perforated space. This point is 
called the limen insulae. The insula is continuous behind with the hippocampal 
convolution. It is divided into a pre-central and a post-central lobe by the sulcus 
centralis, which runs backward and upward from the apex of the insula. The pre- 
central lobe is further subdivided by shallow sulci into three or four short con- 
volutions, the gyri breves insulae, while the post-central lobe is named the gyrus 
longus insulae, and is often bifurcated at its upper extremity. The gray matter of 
the insula is continuous with that of the different opercula, while its mesial surface 
corresponds with the external surface of lenticular nucleus of the corpus striatum, 
from which it is separated by the external capsule and claustrum. 
6. Limbic Lobe (Figs. 564 and 569).-The term limbic lobe or grande lobe 
limbigue was introduced by Broca in 1878, and under it he included two convolu- 
tions-viz., the callosal and hippocampal convolutions, which together arch around THE HEMISPHERES OE THE CEREBRUM 
879 
the corpus callosum and the hippocampal fissure. These he separated on the 
morphological ground that they are well developed in animals possessing a keen 
sense of smell (osmatic animals), such as the dog and fox. To the lobe thus de- 
fined the following parts must be added-viz., the laminae of the septum lucidum, 
together with the fornix and its fimbriae, which may be regarded as forming an 
inner or deep arch; the peduncles and 
longitudinal striae of the corpus cal- 
losum, together with the gyrus den- 
tatus, which form a middle arch, while 
the outer arch is constituted by the 
callosal and hippocampal convolutions; 
the first two arches are separated from 
each other by the corpus callosum. 
Convolutions of the Limbic Lobe.- 
(1) The callosal convolution {gyrus 
jornicatus or gyrus cinguli) (Figs. 562 
and 567) is an arch-shaped convolu- 
tion, lying in close relation to the 
superficial surface of the corpus cal- 
losum, from which it is separated by a slit-like sulcus, the callosal sulcus {sulcus 
corporis callosi). It commences belowthe rostrum of the corpus callosum. The inner 
root of the olfactory tract enters the beginning of the convolution. The callosal con- 
volution curves around in front of the genu, extends along the upper surface of the 
body, and finally turns downward behind the splenium, where it becomes narrow 
because the calcarine fissure cuts it. The narrow portion is the isthmus {isthmus 
gyri fornicati). The isthmus connects the callosal convolution with the gyrus hippo- 
campi. The callosal convolution is separated from the marginal convolution by the 
calloso-marginal sulcus, from the precuneus by the post-limbic sulcus, and from the 
lingual gyrus by the anterior portion of the calcarine fissure. 
(2) The hippocampal convolution {gyrus hippocampi) (Figs. 562 and 563) is 
bounded above by the hippocampal or dentate fissure, and below by the anterior 
part of the collateral fissure. Behind, it is continuous superiorly, through the 
isthmus,with the callosal convolution, and inferiorly with the subcalcarine or lingual 
convolution. Its anterior extremity is recurved in the form of a hook, and is named 
the uncinate convolution or uncus (Fig. 567). Running in the substance of the callosal 
and hippocampal convolutions, and connecting them together, is a tract of arched 
fibres, named the fillet of the gyrus fornicatus or the cingulum. The outer root of the 
olfactory tract passes into the anterior extremity of the hippocampal convolution, 
and the inner root into the commencement of the callosal convolution, so that these 
two convolutions, with the addition of the olfactory tract, present a racquet-like 
appearance-the olfactory tract constituting the handle and the two convolutions 
the circumference of the blade. 
(3) The dentate convolution {gyrus dentatus) (Figs. 562 and 581), also called the 
dentate fascia {fascia dentata hippocampi). It is situated above the gyrus hippo- 
campi, from which it is separated by the hippocampal or dentate fissure {fissura 
hippocampi) (Figs. 562, 564, and 567). The dentate convolution is covered by the 
fimbria, a prolongation of the posterior pillar of the fornix, and is a narrow, elon- 
gated convolution, the free surface of which presents a notched or toothed appear- 
ance, hence its name. Posteriorly it is prolonged as a delicate lamina, the fasciola 
cinerea, around the splenium of the corpus callosum, and becomes continuous on 
the upper surface of that body with its mesial and lateral longitudinal striae. 
Anteriorly it is prolonged into the notch produced by the recurving of the uncus, 
where it forms a sharp curve; from here it can be traced as a delicate band, the 
band of Giacomini, over the uncus, on the outer surface of which it is lost. 
LIMBIC 
LOBE 
SUPERIOR 
ARCH 
OLFACTORY 
LOBE 
INFERIOR 
ARCH 
PEDUNCLE 
Fig. 569.-Scheme of the limbic lobe. (Poirier and 
Charpy.) 880 
THE NER VO US SYSTEM 
The remaining structures which contribute to the formation of the limbic lobe 
will be subsequently described. 
7. The Olfactory Lobe or Rhinencephalon (lobus olfactorius) (Figs. 555 and 
569).-The olfactory lobe is situated on the under surface of the frontal lobe. It is 
rudimentary in man and some other mammals, but in vertebrates generally it is well 
developed, and consists of a distinct extension of the cerebral hemisphere, enclosing 
a portion of the anterior horn of the lateral ventricle. In man it is long and slender, 
and may be described as consisting of two parts, the anterior and posterior olfactory 
lobules. 
The Anterior Olfactory Lobule.-The anterior olfactory lobule is made up of: 
(1) the olfactory bulb; (2) the olfactory tract; (3) the trigonum olfactorium; (4) the 
area of Broca. 
OLFACTORY 
'BULB 
GENU OF 
CALLOSUM 
SYLVIAN 
FISSURE 
ANTERIOR PER- 
'FORATED SPACE 
IN FUNDI- 
BULUM 
.POSTERIOR PER- 
FORATED SPACE 
..CRUS CEREBRI 
MIDDLE CEREBEL- 
LAR PEDUNCLE 
.OBLONGATA 
.CEREBELLUM 
Fig. 570.-Under surface of the brain, showing the superficial origins of the cranial nerves. The Roman 
numerals indicate the nerves. (Testut.) 
(1) The Olfactory Bulb (bulbus olfactorius) (Fig. 570) is an oval mass of reddish- 
gray color, which rests on the cribriform plate of the ethmoid bone below and 
the olfactory sulcus of the orbital surface of the frontal lobe above. It forms 
the anterior expanded extremity of the olfactory tract. Its under surface receives 
the olfactory nerves, which pass upward through the cribriform plate from the 
olfactory region of the nose. Its minute structure will be subsequently described. 
(2) The Olfactory Tract (tractus oljact onus') (Fig. 570), often called the olfactory 
nerve or first cranial nerve, is a band of white matter, triangular on section, the 
apex being directed upward. It lies in the olfactory sulcus on the under surface 
of the frontal lobe. Traced backward, it is seen to divide into two roots, an outer THE HEMISPHERES OE THE CEREBRUM 
881 
and an inner. Some have called the olfactory tubercle a middle root. The outer 
root passes across the outer part of the anterior perforated space to the nucleus 
amygdalae and the anterior part of the gyrus hippocampi. The inner root turns 
sharply inward, and ends partly in Broca's area and partly in the callosal convolu- 
tion; in other words, the inner root is continuous with one extremity and the outer 
root with the other extremity of the limbic lobe (Fig. 569). 
(3) The Trigonum Olfactorium or Olfactory Tubercle is situated between the 
diverging roots of the olfactory tract, and is sometimes described at the middle or 
gray root of the tract. It is part of an area of gray matter, which forms the base 
of the anterior olfactory lobule; another portion of it is termed (4) the area of 
Broca (area parol factoria), the portion of gray matter between the internal root 
and the peduncle of the corpus callosum; and a third portion, of no special sig- 
nificance, is situated external to the outer root of the olfactory tract. This area of 
gray matter is bounded internally and posteriorly by a sulcus, the fissura prima 
(sulcus paroljactorius posterior), which separates it from the peduncle of the corpus 
callosum and from the posterior olfactory lobule. The area of Broca is continuous 
with the gyrus fornicatus, and receives fibres from the inner or mesial root. 
The Posterior Olfactory Lobule.-The posterior olfactory lobule corresponds to 
the portion of the hemisphere called the anterior perforated space (locus perforatus 
anticus or substantia perforata anterior) (Figs. 566 and 570). It is marked off from 
the anterior lobule by the sulcus parolfactorius posterior, and is situated at the com- 
mencement of the fissure of Sylvius. Internally, it is bounded by the peduncle of 
the corpus callosum, and is continuous with the lamina cinerea. Posteriorly it is 
bounded by the optic tract, and it is partially concealed by the temporal lobe which 
overlaps it. It has received the name of anterior perforated space from its being 
perforated by numerous openings, which transmit blood-vessels to the interior of 
the brain, and it corresponds to the under surface of the lenticular nucleus. 
Under Surface or Base of the Encephalon (facies basalis encephali) (Fig. 
570).-Having considered the surface of the hemispheres, the student should 
direct his attention to the base of the brain, before commencing the study of the 
component parts which make up the two hemispheres. 
The base of the brain presents for examination the under surfaces of the frontal 
and temporal lobes; the structures contained in the interpeduncular space, with 
the crura cerebri or cerebral peduncles; the under surfaces of the pons Varolii, 
cerebellum, and medulla oblongata; and the superficial origins of the cranial 
nerves. 
The various objects exposed to view (with the exception of the superficial 
origins of the cranial nerves, which will be considered in another section), in the 
middle line and on either side of the middle line, are here arranged in the order 
they are met with from before backward. 
In the Middle Line. 
Longitudinal fissure. 
Rostrum and peduncles of 
corpus callosum. 
Lamina cinerea. 
Optic commissure. 
Tuber cinereum. 
Infundibulum. 
Pituitary body. 
Corpora albicantia. 
Posterior perforated space. 
Pons Varolii. 
Medulla oblongata. 
On Each Side of the Middle Line. 
Frontal lobe. 
Olfactory lobe. 
The anterior perforated space. 
Fissure of Sylvius. 
Optic tracts. 
Crura cerebri. 
Temporal lobe. 
Hemisphere of cerebellum. THE NERVOUS SYSTEM 
882 
The Longitudinal Fissure (fissura longitudinalis cerebri) (p. 865).-The longi- 
tudinal fissure partially separates the two hemispheres from each other. It 
divides completely the anterior portions of the two frontal lobes; and on raising 
the cerebellum and pons it will be seen to separate completely the two occipital 
lobes; of these two portions of the longitudinal fissure, that which separates the 
occipital lobes is the longer. The intermediate part of the fissure is filled up by the 
great transverse band of white matter, the corpus callosum. In the fissure between 
the two frontal lobes the anterior cerebral arteries ascend on the corpus callosum. 
The Corpus Callosum.-The corpus callosum, the transverse commissure which 
joins the two cerebral hemispheres, is described on p. 886. It terminates at the 
base of the brain by a concave margin, which is connected with the tuber cinereum 
through the intervention of a thin layer of gray substance, the lamina cinerea. This 
may be exposed by gently raising and drawing back the optic commissure. A 
white band may be observed on each side, passing backward from the under sur- 
face of the corpus callosum, across the posterior margin of the anterior perforated 
space to the hippocampal gyrus, where it meets the corresponding outer root 
of the olfactory tract; this band is called the peduncle of the corpus callosum or the 
gyrus subcallosus (pedunculus corporis callosi). The band may be traced upward 
around the genu to become continuous with the striae longitudinales on its upper 
surface. Laterally, this portion of the corpus callosum extends into the frontal 
lobe. 
The Lamina Cinerea.-The lamina cinerea is a thin layer of gray substance, 
extending upward in the anterior portion of the great longitudinal fissure from the 
optic commissure to join the rostrum of the corpus callosum. It is continuous on 
each side with the gray matter of the anterior perforated space, and forms the 
anterior part of the inferior boundary of the third ventricle. The portion of the 
lamina cinerea which is turned upward is called the lamina terminalis. 
The Optic Commissure or Optic Chiasma (chiasmaopticum).-The optic commissure 
is situated in the middle line, immediately in front of the tuber cinereum and below 
the lamina cinerea; that is to say, the commissure is superficial to the lamina in 
the order of dissection when the base is uppermost. It is the point of junction 
between the two optic tracts, and will be described with the cranial nerves. Imme- 
diately behind the diverging optic tracts, and between them and the peduncles 
of the cerebrum (crura cerebri or pedunculi cerebri), is a lozenge-shaped interval, 
the interpeduncular space (fossa interpeduncidaris \Tarini\). The posterior recess 
(recessus posterior) of this space passes for a little way underneath the anterior 
margin of the pons; the anterior recess (recessus anterior) passes between the 
corpora albicantia. The floor of the interpeduncular space is the substantia 
perforata posterior, and in the space are found the following parts: the tuber 
cinereum, infundibulum, pituitary body, corpora albicantia, and the posterior 
perforated space. 
The Tuber Cinereum.-The tuber cinereum is an eminence of gray matter, 
situated between the optic tracts, and extending from the corpora albicantia to the 
optic commissure, to which it is attached; it is connected with the surrounding 
parts of the cerebrum, forms part of the floor of the third ventricle, and is con- 
tinuous with the gray substance in that cavity. From the middle of its under sur- 
face a conical tubular process of gray matter, about two lines in length, is con- 
tinued downward and forward to be attached to the posterior lobe of the pituitary 
body. This is the infundibulum, and its canal, which is funnel-shaped, com- 
municates with the third ventricle. 
The Pituitary Body (hypophysis cerebri).-The pituitary body is a small, reddish- 
gray, vascular mass, weighing from five to ten grains, and of an oval form, situated 
in the sella turcica, where it is retained by a process of dura mater, named the 
diaphragma sellae (Fig. 544). This process of the dura covers in the sella turcica, THE HEMISPHERES OE THE CEREBRUM 
883 
and has a small hole in its centre through which the infundibulum passes, the 
foramen diaphragmatis sellae (Fig. 544). 
Structure.-The pituitary body is very vascular, and consists of two lobes, 
separated from one another by a fibrous lamina. Of these, the anterior and the 
larger is of an oblong form, and somewhat concave behind, where it receives 
the posterior lobe, which is round. The two lobes differ both in development 
and structure. The anterior lobe, of a dark, reddish-brown color, is developed 
from the epiblast of the buccal cavity, and resembles to a considerable extent, in 
microscopic structure, the thyroid body. It consists of a number of isolated 
vesicles and slightly convoluted tubules, lined by epithelium and united together 
by a very vascular connective tissue. The epithelium is columnar and occasion- 
ally ciliated. The alveoli sometimes contain a colloid material, similar to that 
found in the thyroid body, and their walls are surrounded by a close network of 
lymphatic and capillary blood-vessels. The posterior lobe is developed as an 
outgrowth from the embryonic brain, and during foetal life contains a cavity 
which communicates through the infundibulum with the cavity of the third 
ventricle. In the adult it becomes firmer and more solid, and consists of a 
sponge-like connective tissue arranged in the form of reticulating bundles, 
between which are branched cells, some of them containing pigment. In the 
lower animals the two lobes are quite distinct, and it is only in the mammalia 
that they become fused together. The pituitary body is believed to be a ductless 
gland, which furnishes an internal secretion. In many cases of acromegaly the 
gland is enlarged or otherwise diseased. 
The Corpora Albicantia or Corpora Mamillaria.-The corpora albicantia or mam- 
illaria are two small, round, white masses, each about the size of a pea, placed 
side by side immediately behind the tuber cinereum, and connected with each 
other across the mesial plane. They are mainly formed by the anterior crura or 
pillars of the fornix, which, after descending to the base of the brain, are 
twisted upon themselves to form loops, and constitute the white covering of the 
corpora albicantia. A second fasciculus, the bundle of Vicq d'Azyr (fasciculus 
thalamomamillaris) (Figs. 574 and 586), converges from the optic thalamus, and 
enters the anterior part of each body on its dorso-mesial surface. The corpora 
albicantia are composed externally of white substance, and internally of gray 
matter; the nerve-cells of the gray matter are arranged in two sets, inner and 
outer, the cells of the former set being the smaller. Each corpus is connected 
to the tegmentum by a small bundle of fibres, the peduncle of the mamillary 
body (pedunculus corporis mamillaris (Fig. 586). At an early period of foetal 
life the corpora albicantia are blended together into one large mass, but become 
separated about the seventh month. In most vertebrates there is only one median 
corpus albicans. 
The Posterior Perforated Space or Lamina or the Pons Tarini (locus perforatus 
posticus, substantia perforata posterior).-The posterior perforated space cor- 
responds to a whitish-gray fossa placed between the corpora albicantia in front, 
the pons Varolii behind, and the crus cerebri on either side. It is in reality a 
visible portion of the substantia nigra and forms the floor of the interpeduncular 
fossa. It forms the posterior part of the floor of the third ventricle, and is per- 
forated by numerous small orifices for the passage of the postero-median ganglionic 
branches of the posterior cerebral and posterior communicating arteries. Slender 
white bands are observed in some subjects coming from the gray matter of the 
posterior perforated space, passing around the crura cerebri, and entering into the 
pons Varolii. The bands bear the name of the taenia pontis. 
The Pons Varolii (p. 922).-The pons Varolii is situated immediately behind the 
two crura of the cerebrum. It consists of a broad band of white fibres, which pass 
transversely from one cerebellar hemisphere to the other; the band becoming 884 
THE NERVOUS SYSTEM 
narrower as it enters the cerebellum. In the middle line on its under surface a 
narrow groove runs from before backward and accommodates the basilar artery. 
The Medulla Oblongata, Medulla Spinalis or Bulb(p. 938).-The medulla oblongata 
emerges from the posterior border of the pons Varolii; it is pyramidal in form, and 
is continuous below with the cervical portion of the spinal cord. It is marked on 
its ventral surface by a median fissure, continuous below with the anterior median 
fissure of the cord, and on either side by secondary fissures and columns, which 
will be described in the sequel. 
The Frontal Lobe.-The under surface of the frontal lobe, sometimes named 
the orbital lobe, is seen on the anterior part of the base of the brain on either side 
of the median line. It has already been described (p. 874). 
The Olfactory Lobe (p. 880). 
The Anterior Perforated Space (p. 881). 
The Fissure of Sylvius (fissura lateralis cerebri).-The fissure of Sylvius at the 
base of the brain separates the frontal from the temporal lobe, and lodges the 
middle cerebral artery. It has also been described (p. 866). 
Fig. 571.-Section of the brain. Made on a level with the corpus callosum. 
The Optic Tracts.-The optic tracts are well-marked, flattened bands of fibres, 
which run obliquely across the crus cerebri on either side, and unite anteriorly to 
form the optic commissure. They will be described in connection with the cranial 
nerves. 
The Crura Cerebri or the Peduncles of the Cerebrum (pedunculi cerebri) (p. 906).- 
The crura cerebri are two thick cylindrical bundles of white matter, which appear THE HEMISPHERES OF THE CEREBRUM 
885 
in front of the anterior border of the pons, and diverge as they pass forward and 
outward to enter the under surface of each hemisphere. They compose the chief 
portion of the mesencephalon. Each crus is about three-quarters of an inch in 
length, and is about the same in breadth anteriorly, but somewhat less posteriorly. 
They are marked upon their surface with longitudinal striae, and each is crossed, 
just before entering the hemisphere, by the fourth nerve and the optic tract, the 
latter of which is adherent by its upper surface to the peduncle. Each crus is 
composed of two parts, a superior or dorsal part, and an inferior, ventral, or pedal part. 
The dorsal part is known as the tegmentum of the crus cerebri (tegmentum), the fibres 
(p. 908) of which pass up into the region beneath the optic thalamus, a region known 
as the1 subthalamic tegmental region. The ventral portion is known as the crusta 
(basis pedunculi), the fibres of which (p. 907) pass up external to the optic thala- 
mus and into the internal capsule. On the surface of the crus are two grooves 
which mark the separation between the tegmentum and the crusta. One groove 
is on the inner (mesial) surface; it is called the sulcus nervi oculo-motorii, and 
from it comes the third or motor oculi nerve. The other groove on the outer 
(lateral) surface is called the sulcus lateralis mesencephali. It passes down into the 
interval between the superior and middle cerebellar peduncles. From the outer 
surface of the tegmentum some slender fibres, called the lateral fillet (lemniscus 
lateralis), pass to the inferior quadrigeminal body. If a transverse section of the 
crus is made, the substantia nigra is seen between the tegmentum and the crusta. 
It is a band of pigmented gray matter which begins somewhat below the 
upper margin of the pons and ascends into the subthalamic area. 
The Temporal Lobe (Fig. 878).-The under surface of the temporal lobe is 
visible at the base of the brain, on either side of the crura and the structures con- 
tained in the interpeduncular space. It is separated anteriorly from the frontal 
lobe by the fissure of Sylvius, and behind is limited by the anterior border of 
the lateral hemispheres of the cerebellum. The fissures and lobes on its surface 
have already been described (p. 877). 
The Hemispheres of the Cerebellum (hemisphaeria cerebelli) (p. 929).-The 
hemispheres of the cerebellum are situated on either side of the middle line, 
and cover the occipital lobes of the cerebrum, when viewed from the base. 
'The cerebellum differs much in appearance from the rest of the encephalon, 
being of a darker color, while its convolutions are smaller and narrower, are 
arranged like the leaves of a book, and hence are called folia. 
General Arrangement of the Parts Composing the Cerebrum.-Each hemi- 
sphere, as already stated, consists of a central cavity, the lateral ventricle, surrounded 
by thick and convoluted walls of nervous tissue. 
Interior of the Cerebrum.-If the upper part of either hemisphere is removed 
with a knife, about half an inch above the level of the corpus callosum, its internal 
white matter will be exposed. It is an oval-shaped centre, of white substance, 
surrounded on all sides by a narrow convoluted margin of gray matter, which 
presents an equal thickness in nearly every part. This white central mass has 
been called the centrum ovale minus. Its surface is studded with numerous minute 
red dots (puncta vasculosa), produced by the escape of blood from divided blood- 
vessels. In inflammation or great congestion of the brain these are very numerous 
and of a dark color. If the remaining portion of one hemisphere is slightly sepa- 
rated from the other, a broad band of white substance will be observed, connect- 
ing them at the bottom of the longitudinal fissure; this is the corpus callosum. The 
margins of the hemispheres which overlap this portion of the brain are called the 
labii cerebri. Each labium is part of the callosal convolution already described; 
and the space between it and the upper surface of the corpus callosum is termed 
the callosal sulcus (sulcus corporis callosi) (Figs. 562 and 567). The hemispheres 
should now be sliced off to a level with the upper surface of the corpus callosum, THE NEU VO US SYSTEM 
886 
when the white substance of that structure will be seen connecting the two 
hemispheres. The large expanse of medullary matter now exposed, surrounded 
by the convoluted margin of gray substance, is called the centrum ovale majus 
of Vieussens (Fig. 571). 
The Corpus Callosum (Figs. 571, 574, and 586).-The corpus callosum is a thick 
stratum of transversely directed nerve-fibres, by which probably almost every 
part of one hemisphere is connected with the corresponding part of the other hemi- 
sphere (Figs. 572 and 573). It connects not only corresponding but also non- 
corresponding portions of the cortices. The fibres of this body, when they pass 
from it into the hemispheres radiate in various directions (radiatio corporis callosi) 
between the fibres of the corona radiata, to terminate in the gray matter of the 
periphery. According to Cajal the termination is in the layer of small pyramidal 
cells of the cortex. The corpus callosum thus connects the two hemispheres of 
the brain, forming their great transverse commissure, and at the same time roofs 
in the lateral ventricles (Fig. 575). The best conception of its size and form is 
Fig. 572.-Diagram of coronal section of cerebrum to 
show course of fibres of callosum. (Testut.) 
Fig. 573.-Diagram of horizontal section of cerebrum 
to show course of fibres of callosum. (Testut.) 
obtained by making an anterior posterior vertical section through the centre of 
the brain (Figs. 574 and 586). It is then seen to be a long, thick, irregularly 
flattened arch, body of the corpus callosum (tr uncus cor ports callosi); in front taking 
a sharp bend, the genu (genu corporis c allo si) (Fig. 577), and dipping downward 
and backward to the base of the brain by a reflected portion, the beak or rostrum 
(rostrum corporis callosi), which is connected with the lamina cinerea; behind it 
terminates by a rounded end, which is folded over and is named the splenium 
(splenium corporis callosi) (Fig. 577). The corpus callosum is about four inches 
in length, and extends to within an inch and a half of the anterior and two 
inches and a half of the posterior extremity of the cerebrum. It is somewhat 
broader behind than in front, and is thicker at either end than in its central 
part. The reflected anterior portion of the corpus callosum is called the beak 
or rostrum; it becomes gradually thinner as it descends, and is attached by 
its lateral margins to the frontal lobes. At its termination, in addition to 
joining the lamina cinerea, the corpus callosum gives off on each side a band 
of white substance, the peduncle of the corpus callosum (gyrus subcallosus or 
pedunculus corporis callosi), already described (p. 882). 
Posteriorly, the corpus callosum forms a thick rounded fold, called the pad or 
splenium, which is free for a little distance as it curves forward, and is then con- 
tinuous by its under surface with the fornix. * The splenium overlaps the mesen- 
cephalon, but is separated from it by the pia mater, which is prolonged forward to THE HEMISPHERES GE THE CEREBRUM 
887 
form the velum interpositum (Fig. 548). On the upper surface of the corpus cal- 
losum the structure is very apparent, the fibres being collected into coarse transverse 
bundles (Fig. 571). Along the middle line is a longitudinal depression, the so-called 
raphe, bounded laterally on each side by two or more slightly elevated longitudinal 
bands (Fig. 571). The internal band on each side is called the stria longitudinalis 
medialis or nerve of Lancisi. The external band is the stria longitudinalis lateralis or 
taenia tectae. The external band is beneath the convolution of the corpus callosum. 
There is an attenuated sheet of gray matter with the external and internal striae, and 
it, with the striae, constitutes the so-called gyrus supra-callosus (pp. 882 and 886). 
On each side of the middle line the under surface of the corpus callosum forms the 
roof of the lateral ventricle, while in the mesial plane it is continuous behind with 
the fornix, being separated from it in front by the septum lucidum, which forms 
1. Convolution of the corpus callosum. Above it is 
the calloso-marginal fissure. 
2. Fissure of Rolando. 
3. The parieto-occipital fissure. 
4, 4, point to the calcarine fissure, which is just 
above the numbers. Between 2 and 3 are the convo- 
lutions of the quadrate lobe. Between 3 and 4 is the 
cuneate lobe. 
5. The corpus callosum. 
6. The septum lucidum. 
7. The fornix. 
8. Anterior crus of the fornix, descending to the 
base of the brain, and turning on itself to form the 
corpus albicans. The bundle of Vicq d'Azyr is indi- 
cated by a dotted line. 
Fig. 574.-Vertical median section of the encephalon, showing the parts of the middle line. 
9. The optic thalamus. Behind the anterior crus of 
the fornix a shaded part indicates the foramen of 
Monro; in front of the number an oval mark shows 
the position of the gray or middle commissure. 
10. The velum interpositum. 
11. The pineal gland. 
12. The corpora quadrigemina. 
13. The crus cerebri. 
14. The valve of Vieussens (to right of the number). 
15. The pons Varolii. 
16. The third nerve. 
17. The'pituitary body. 
18. The optic nerve. 
19 points to the anterior commissure, indicated by 
the oval outline behind the number. 
a vertical partition between the two ventricles (Figs. 574 and 586). On each 
side the fibres of the corpus callosum extend into the substance of the hemispheres, 
connecting them together. The greater thickness of the two extremities of this 
commissure is explained by the fact that the fibres from the anterior and posterior 
parts of each hemisphere cannot pass directly across, but have to take a curved 
direction. The part of the corpus callosum which curves forward on each side 
from the genu into the frontal lobe and covers the front part of the anterior cornu 
of the lateral ventricle is called the forceps anterior or forceps minor. The part which 888 
THE NERVOUS SYSTEM 
curves backward from each side of the splenium into the occipital lobe is known 
as the forceps posterior or forceps major. Between these two parts on each side is 
a collection of fibres, which cover in the body of the lateral ventricle. These 
constitute the tapetum or mat. The tapetum helps to form the roof and outer wall 
of the posterior horn of the lateral ventricle and the outer wall of the posterior 
portion of the descending horn of the ventricle. These fibres were formerly 
regarded as fibres of the callosum, but in reality are the fibres of the fasciculus 
occipito-frontalis which diverge posteriorly. The corpus callosum contains a few 
projection fibres, but is chiefly composed of association fibres and branches 
from both association and projection fibres. 
An incision should now be made through the corpus callosum, on either side of the raph^, 
when two large irregular cavities will be exposed, which extend through a great part of the 
length of each hemisphere. These are the lateral ventricles. 
The Lateral Ventricle (ventriculus lateralis') (Fig. 575).-The lateral ventricle is an 
irregular cavity situated in the lower and inner parts of the cerebral hemisphere. 
Fig. 575.-The lateral ventricles of the brain. 
There are two lateral ventricles, one being placed on either side of the middle line. 
They are separated from each other by a mesial vertical partition, the septum lucidum 
(Figs. 574 and 586), but communicate with the third ventricle and indirectly with 
each other through the foramen of Monro (Figs. 548, 574, and 575). They are lined 
by a thin, diaphanous membrane, the ependyma, which is neuroglia covered by 
ciliated epithelium. The layer of neuroglia is absent over the optic thalamus and 
the choroid plexus. The lateral ventricles communicate with each other and with THE HEMISPHERES OF THE CEREBRUM 
889 
the third ventricle, and are moistened by the cerebro-spinal fluid, which, even in 
health, may be secreted in considerable amount. Each lateral ventricle consists of 
a central cavity or body and three prolongations from it, termed cornua. The 
anterior cornu curves forward and outward into the frontal lobe; the posterior 
backward and inward into the occipital lobe; and the middle descends into the 
temporal lobe. 
The Septum Lucidum (septum pellucidum) (Figs. 574, 586, and 587) is composed 
of two thin, vertical laminae, which lie in the median line with their mesial sur- 
faces almost in contact. These sheets are triangular and can be separated, and 
the cavity thus shown is called the fifth ventricle (cavum septi pellucidi) (Fig. 575). 
It contains a little fluid, but does not communicate with the general ventricular 
cavity. Each lamina of the septum lucidum bears the name of the lamina septi 
pellucidi. The front part of the septum lucidum lies behind the genu of the corpus 
callosum, and below it passes toward the base of the brain between the fornix and 
the posterior margin of the rostrum, to terminate in the subcallosal gyrus. Pos- 
teriorly, the septum lucidum passes back between the fornix and the body of the 
corpus callosum, being attached to each structure. 
The Central Cavity or Body of the lateral ventricle (ventriculus lateralis [pars 
centralis]) (Fig. 575) is situated in the lower part of the parietal lobe. It is an 
irregularly curved cavity, triangular in shape on transverse section, and presents 
a roof, a floor, an inner wall, and an outer wall. Its roof is formed by the under 
surface of the corpus callosum; its mesial wall is the septum lucidum, which sepa- 
rates it from the opposite ventricle and connects the under surface of the corpus 
callosum with the fornix; its external wall is the internal capsule; its floor is formed 
by the following parts, enumerated in their order of position, from before back- 
ward ; the caudate nucleus of the corpus striatum, taenia semicircularis, the epithe- 
lial covered optic thalamus, the epithelial covered choroid plexus, the superior 
surface of the body of the fornix and part of its posterior pillar. 
The Anterior Cornu or Frontal Horn (cornu anterius) (Fig. 575) passes forward and 
outward, with a slight inclination downward, from the foramen of Monro into the 
frontal lobe, curving round the anterior extremity of the caudate nucleus. Its roof 
is the forceps minor of the corpus callosum, and its floor the upper surface of 
the reflected portion of the corpus callosum, the rostrum. It is bounded mesially 
by the anterior portion of the septum lucidum, and externally by the head of 
the caudate nucleus of the corpus striatum. Its apex reaches the posterior surface 
of the genu of the corpus callosum. 
The Foramen of Monro (foramen interventriculare) (Figs. 548, 574, 575, and 587) 
extends from the anterior and superior extremity of the third ventricle and the point 
of junction of the anterior horn with the central cavity of the lateral ventricle. It 
lies between the anterior pillar of the fornix and the anterior margin of the optic 
thalamus This foramen connects the third ventricle with the two lateral ventricles. 
The Posterior Cornu or Occipital Horn (cornu posterius) (Fig. 575) curves backward 
into the substance of the occipital lobe, its direction being backward and outward, 
and then inward; its concavity is therefore directed inward. Its roof is formed by the 
tapetum of the corpus callosum passing to the temporal and occipital lobes, which 
also helps to bound this horn externally. On its mesial wall is seen a longitudinal 
eminence, which is in an involution of the ventricular wall produced by the 
calcarine sulcus; this is called the hippocampus minor (calcar avis). Just above this 
the forceps major of the splenium, sweeping around to enter the occipital lobe, 
causes another projection, which is known as the bulb of the posterior horn (bulbus 
cornu posterius). The hippocampus minor and bulb of the posterior horn are 
extremely variable in their degree of development, being in some cases ill defined, 
while in others they are unusually prominent. The balance of the posterior horn 
is bounded by the white substance of the occipital lobe. 890 
THE NERVOUS SYSTEM 
Between the middle and posterior cornu is a triangular area, called the trigonum 
ventriculi (see Descending Horn). 
The Middle or Descending Cornu or Temporal Horn (cornu inferius) (Figs. 575, 581, 
and 583),the largest of the three traverses thetemporal lobeof the brain,formingin 
its course a remarkable curve around the back of the optic thalamus. It passes at 
first backward, outward, and downward, and then curves around the crus cerebri, 
forward and inward, to within an inch of the apex of the temporal lobe, its direction 
being fairly well indicated on the surface of the brain by that of the parallel sulcus. 
Its antero-external boundary or roof is formed by the under surface of the tapetum of 
the corpus callosum, the pulvinar of the optic thalamus, and the inferior layer of the 
internal capsule. The tail of the nucleus caudatus of the corpus striatum and the 
taenia semicircularis are also prolonged into it, and extend forward in the roof of 
the descending horn to its extremity, where they end in a mass of gray matter, the 
amygdaloid nucleus (nucleus amygdalae); this nucleus is merely a localized thick- 
ening of the adjacent gray cortex. The posterior boundary or floor of the lateral 
ventricle presents for examination the following parts: the hippocampus major 
(hippocampus), pes hippocampi (digitationes hippocampi), eminentia collateralis 
or pes accessorius, corpus fimbriatum (fimbria hippocampi), prolonged from the 
posterior pillar of the fornix, and the choroid plexus. Along the medial aspect of 
the descending cornu there is a cleft-like opening, the choroid fissure, which is 
the lower part of the trans- 
verse fissure, through which 
the choroid plexus of the pia 
mater is invaginated into the 
ventricle, but covered by the 
epithelium of the ependyma, 
which is pushed in before it. 
Upon the inner wall are also 
noted the epithelial covering, 
the pulvinar, and the dentate 
convolution or fascia (fascia 
dentata hippocampi) (Figs. 562 
and 581), which is the irregu- 
lar and free cortical margin. 
'Die Corpus Striatum (Figs. 
575, 576, 577, 580, and 584), 
the basal ganglion of the hemi- 
sphere, has received its name 
from the striped appearance 
which its section presents, 
in consequence of diverging 
white fibres being mixed with 
the gray matter which forms 
the greater part of its sub- 
stance. It is situated to the 
front and to the outside of the 
optic thalamus. The corpus 
striatum measures about two 
inches in its antero-posterior 
diameter andone and a quarter inches transversely.1 The larger portion of this body 
is embedded in the white substance of the hemisphere, and is therefore external 
to the ventricle. It is termed the extra-ventricular portion or the lenticular nucleus 
ANTERIOR PILLARS 
OF FORNIX 
CLAUS-. 
TRUM 
POSTERIOR PILLAR 
OF FORNIX 
Fig. 576.-Horizontal section of left hemisphere through the basal 
ganglia, viewed from above. C.N., caudate nucleus. (Testut.) 
' Anatomy of the Brain and Spinal Cord. By Harris E. Santee. THE HEMISPHERES OF THE CEREBRUM 
891 
(nucleus lentiformis)-, a part, however, is visible in the ventricle and its anterior 
cornu; this is the intra-ventricular portion or the caudate nucleus (nucleus caudatus). 
These two portions are separated by the internal capsule. 
The caudate nucleus (nucleus caudatus) (Figs. 576,577,579, and 580) is a pear- 
shaped, highly arched mass of gray matter; its broad anterior extremity, the bulb 
or head (caput nuclei caudati), is directed forward into the forepart of the body 
and anterior cornu of the lateral ventricle; its narrow posterior end, the tail or 
surcingle (cauda nuclei caudati), is directed outward and backward on the floor 
of the body of the lateral ventricle and on the outer side of the optic thalamus, 
from which structure it is separated by the taenia semicircularis (Fig. 577); it 
is continued downward into the descending cornu of the lateral ventricle and 
Genu of 
Corp. Callosum. 
For- 
nix. 
Tail of • 
Caudate Nucleus 
Splenium of 
Corp. Callosum. 
Mid. Cornu, 
of Lat. Venu 
Fig. 577.-Middle part of a horizontal section through the cerebrum at the level of the dotted line in the 
small figure in one hemisphere. (From Ellis, after Dalton.) 
is continued forward in the roof to terminate in the amygdaloid nucleus, a collec- 
tion of gray matter in the apex of the temporal lobe. It is covered by the lining 
of the ventricle, and crossed by some veins of considerable size. It is separated 
from the extra-ventricular portion, in the greater part of its extent, by a lamina 
of white matter which is called the internal capsule, but the two portions of the 
corpus striatum are united in front. 
The lenticular nucleus (nucleus lentijormis) (Figs. 576, 577, 579, and 580) is a 
mass of gray matter which lies external to the caudate nucleus and the thalamus, 
and is only seen in sections of the hemisphere. The laminae of the internal capsule 
separate it from the ventricle. If a coronal section is made through the anterior 
portion of the lenticular nucleus, it is seen to be continuous below with the head of 
the caudate nucleus (Fig. 578). Above strands of gray matter join the two nuclei, THE NERVOUS SYSTEM 
892 
and these bands pass through the anterior part of the white internal capsule and 
give it a striated appearance; hence the term corpus striatum, which is applied to 
the mass of which the two nuclei are parts. When divided horizontallv, it pre- 
sents, to some extent, the appearance of a biconvex lens, while a vertical trans- 
verse section of it gives a somewhat triangular outline. It does not extend as far 
forward or backward as the nucleus caudatus. It is bounded externally by a 
lamina of white matter called the external capsule (capsula externa) (Figs. 576, 
577, 578, and 579), on the outer surface of which is a thin layer of gray matter 
termed the bulwark or claustrum (Figs. 576, 577, 578, and 579). The claustrum 
presents ridges and furrows on its outer surface, corresponding to the convolu- 
tions and sulci of the island of Reil, from which it is separated by a thin white 
lamina (Figs. 576, 577, and 578). 
Upon making a transverse vertical section through the middle of the lenticular 
nucleus, it is seen to present two white lines, external and internal medullary 
laminae (laminae medullare externa et interna) (Fig. 579), parallel with its lateral 
border, which divide it into three zones, of which the outer and largest is of a 
reddish color, and is known as the putamen, while the two inner are paler and of a 
yellowish tint, and constitute the globus pallidus (Figs. 578 and 579). All three 
zones are marked by fine radiating white fibres, which are most distinct in the 
putamen. The gray matter of the corpus striatum is traversed by nerve-fibres, 
some of which are believed to originate in it. The cells of the corpus striatum 
are multipolar, both large and small; those of the lenticular nucleus containing 
yellow pigment. 
The internal capsule (capsula interna) (Figs. 576, 577, 578, 579, and 580) is 
formed by fibres of the crusta of the crus cerebri, supplemented by fibres derived 
from the corpus striatum and optic thalamus on each side. Sagittal section ex- 
hibits a superior lamina and an inferior lamina, continuous with each other behind, 
but separated in front by the Sylvian fissure. The inferior lamina is thin and 
its fibres terminate in the parietal and temporal lobes. The superior lamina 
is thick, contains most of the crusta, and the term internal capsule as usually 
employed is synonymous with it. In horizontal section (Figs. 576, 577, 578, 
and 579) the internal capsule is seen to be somewhat abruptly curved, with its 
convexity inward; the prominence of the curve is called the knee or genu of the 
internal capsule (genu capsule internal) (Fig. 578), and projects between the cau- 
date nucleus and the optic thalamus. The portion in front of the genu is termed 
the frontal portion, the anterior limb or the lenticulo-striate division (pars frontalis 
capsulae internae), and separates the lenticular from the caudate nucleus; the por- 
tion behind the genu is the occipital portion, the posterior limb or the lenticulo-optic 
division (pars occipitalis capsulae internae), and separates the lenticular nucleus 
from the optic thalamus. 
Fibres of the Internal Capsule (Figs. 578 and 579). Inferior Lamina.-The 
fibres of the inferior lamina of the internal capsule pass externally under the len- 
ticular nucleus, over the amygdala and descending horn of the lateral ventricle, 
and reach the parietal lobe and the temporal lobe. The motor fibres constitute 
a portion of the motor temporo-pontal tract which extend from the temporal cortex 
to the nucleus pontis. The sensory fibres consist of a portion of the acustic radia- 
tion, which passes from the corpus geniculata interna to the auditory cortex in the 
temporal lobe, and ansa peduncularis, a tract of common sensation which passes 
from the optic thalamus to the sensory region of the cortex. Some of the fibres 
of the median fillet join the ansa peduncularis and pass through the inferior lamina. 
Superior Lamina.-This portion is often spoken of as though it were the entire 
internal capsule. It contains the greater part of the crusta and enters the 
corona radiata. The pyramidal tract is in the knee of the internal capsule. Its 
fibres come from the cortical region about the central sulcus of Rolando and THE HEMISPHERES OE THE CEREBRUM 
893 
pass through the knee of the internal capsule; most of them, by way of the 
middle of the crusta, to reach the spinal cord (p. 907); some of them end in the 
pons and medulla. The anterior segment of the superior lamina of the internal 
capsule contains motor fibres which come from the prefrontal region of the 
cortex and pass by way of the inner one-fifth of the crusta to the nucleus pontis 
B. Kn. 
Fs 
Vh. 
.st. a. 
.1. stric. 
Facialis. 
c. ext. 
Knie. ic.. 
Hypoglossus- 
.J. 
Operc. 
cl. 
Arm- 
I. optic 
Bein.. 
S. B. 
■ Ti 
-r. lie. 
• Auditory 
tract 
S.. 
C.A.. 
Hh. 
■SS 
Tt 
calc.. 
Fig. 578.-Horizontal section through the right hemisphere. B. kn, knee of corpus callosum; Vh, anterior 
horn of lateral ventricle; F3, inferior part of third frontal convolution; I. stric, lenticulo-striate division of in- 
ternal capsule; Knie. ic, knee of internal capsule; I. optic, lentieulo-optic division of internal capsule; Th, optic 
thalamus; J, island of Reil; cl, claustrum; Operc, operculum; T\, first temporal convolution; r. lie, retrolenticular 
region of internal capsule; C.A., hippocampus major; calc, calcarine fissure; Hh, posterior horn of lateral ventricle; 
<S»S, optic radiation of Gratiolet; T^, second temporal convolution; Facialis, position in capsule of motor tract 
to the face; Hypoqlossus, position of tract to the tongue; Arm, position of tract to the arm; Bein, position of 
tract to the leg; S.B., sensory fibres; S, visual tract; A, auditory tract. (M. Allen Starr, after von Monakow.) 
and nuclei of cranial nerves. These fibres constitute the fronto-pontal tract 
(tractus cerebrocorticojrontalis pontalis}. In the posterior segment of the supe- 
rior lamina of the internal capsule is a part of the tract from the temporal 
cortex to the nucleus pontis and the nuclei of cranial motor nerves, the balance 894 
THE NERVOUS SYSTEM 
of which tract is in the inferior lamina. This path occupies the outer one-fifth 
of the crust a, and is the temporo-pontal tract (tractus cerebrocorticopontalis tem- 
poralis). 
The sensory fibres include common sensory fibres and fibres of special sense. 
Fibres of common sensation exist in both the anterior and posterior segments, 
and these fibres pass from the optic thalamus to the sensory region of the cortex, 
and are known as the cortical fillet. The fibres of special sense are found where 
the superior lamina joins the inferior lamina. 
The optic radiations of Gratiolet (radiatio occipitothalamica [Gratioletty are in 
the portion back of the lenticular nucleus, and pass from the-optic thalamus 
and corpus geniculatum externum to the cuneus. 
The auditory radiations (radiatio temporothalamica) are also back of the len- 
ticular nucleus and pass from the corpus geniculatum externum to the temporal 
cortex. 
Numerous fibres of the internal capsule give off collaterals which reach the 
opposite hemisphere by way of the corpus callosum, none of them reaching the 
cortex. 
Note.-The above description of the fibres of the internal capsule is largely taken from 
the Anatomy of the Brain and Cord, by Harris E. Santee, M.D. 
As the fibres of the internal eapsule ascend to reach the various convolutions 
of the cerebral hemisphere they spread out like an open fan. This expansion 
is the corona radiata. The constituent parts and fibre-groups of the internal 
capsule are shown in Figs. 578 and 579. 
The external capsule (capsula externa) (Figs. 576, 577, 578 and 579) is a lamina 
of white matter, situated on the outer side of the lenticular nucleus, between it 
and the claustrum, and is continuous' 
with the internal capsule in front 
of and behind the putamen. It is 
made up of fibres derived partly from 
the anterior white commissure (Fig. 
580) and partly from the subthalamic 
region. 
The Claustrum (Figs. 576, 577, 578, 
and 579) is a thin layer of gray mat- 
ter, situated on the outer surface of 
the external capsule. On transverse 
section it is seen to be triangular, 
with its apex directed upward and its 
base downward. Its inner surface, 
which is contiguous to the external 
capsule, is smooth, but its outer sur- 
face presents ridges and furrows 
which correspond with the convolutions and sulci of the island of Reil, with 
which it is in close relationship. The claustrum is regarded as a detached por- 
tion of the gray matter of the island of Reil, from which it is separated by a 
layer of white fibres, the band of Baillarger (capsula extrema) (Figs. 576 and 577). 
The cells of the claustrum are small and spindle-shaped, and contain yellow 
pigment; they are similar to those found in the deepest layer of the cortex. 
The Taenia Semicircularis (stria terminalis) (Figs. 575, 577, and 584) is a narrow, 
whitish band of medullary substance, situated in the depression between the cau- 
date nucleus and the optic thalamus. Anteriorly its fibres are partly continued into 
the anterior pillar of the fornix; some, however, pass over the anterior commissure 
to the gray matter between the caudate nucleus and septum lucidum, while 
Fig. 579.-Scheme of the internal capsule. (Jakob.) THE HEMISPHERES OF THE CEREBRUM 
895 
others penetrate the caudate nucleus. Posteriorly it is continued into the roof of the 
middle or descending horn of the lateral ventricle, at the extremity of which it enters 
the amygdaloid nucleus, an oval mass of gray matter, situated in the roof of the 
lower extremity of the descending horn. Like the corpus striatum, it is formed 
by a localized thickening of the gray matter of the cortex cerebri. Superficial to it 
is a large vein, vena corporis striati, which receives numerous small veins from the 
surface of the corpus striatum and optic thalamus; it unites with the choroid 
vein to form the vein of Galen (p. 856). On the surface of the vein of the 
corpus striatum is a narrow band of white fibres, named the lamina cornea. 
The remains of the corpus callosum should now be removed in order to expose the fornix. 
The Fornix (Figs. 574, 575, 576, 577, 580, 582, 583, 586, and 587).-The fornix 
is a longitudinal, arch-shaped lamella of white matter, situated beneath the 
corpus callosum, with which it is continuous behind, but from which it is sep- 
arated in front by the septum lucidum. It may be described as consisting of 
two symmetrical halves, one for either hemisphere. The two portions are not 
united to each other in front and behind, but their central parts are joined together 
in the middle line. The two anterior, separated parts are called the anterior 
pillars; the intermediate united portions constitute the body of the fornix; and 
the posterior parts, which are also separated from each other, are called the 
posterior pillars. 
The Body of the Fornix (corpus fornicis) is triangular, narrow in front, broad 
behind. Its upper surface is connected, in the median line, to the septum lucidum 
in front, and the corpus callosum behind; laterally this surface forms part of the 
floor of each lateral ventricle. Its under surface rests upon the velum interpositum, 
which separates it from the third ventricle and the inner portion of the upper 
surface of the optic thalami. Its outer edge, on each side, is free, and is connected 
with the choroid plexuses. 
The Anterior Pillars of the Fornix (columnae fornicis') arch downward toward 
the base of the brain and are separated from each other by a narrow interval. 
They are composed of white fibres, which descend immediately behind the 
anterior commissure, where each anterior pillar passes through the inner part of 
the optic thalamus of that side. At the base of the brain each pillar becomes 
twisted upon itself to form a loop, somewhat resembling the figure 8. The lowest 
part of the loop constitutes the white matter of the corresponding corpus albicans, 
from which the fibres can apparently be traced upward and backward, as the bundle 
of Vicq d'Azyr, into the substance of the corresponding optic thalamus (Figs. 574 
and 586). It must be stated, however, that there is probably no direct continuity 
between this bundle and the anterior pillar of the fornix-the latter possibly ending 
in the gray matter of the corpus albicans. The anterior pillars of the fornix are 
joined in their course by the peduncles of the pineal gland and the superficial fibres 
of the taenia semicircularis, and receive fibres from the septum lucidum. Zucker- 
kandl describes an olfactory fasciculus, which becomes detached from the main 
portion of the anterior pillar of the fornix, and passes downward, in front of the 
anterior commissure, to the base of the brain, where it divides into two bundles, 
one joining the inner root of the olfactory tract; the other, the peduncle of the 
corpus callosum, and through it reaching the hippocampal convolution. 
Between the anterior pillars of the fornix and the anterior extremity of the 
optic thalamus an oval aperture is seen on each side; this is the foramen of Monro 
(foramen interventri culare) (Figs. 548, 574, 575, and 587). The two openings 
descend toward the middle line, and lead into the upper part of the third ven- 
tricle. Through this foramen the lateral ventricles communicate with the third 
ventricle, and consequently with each other; through it also the two choroid plex- 
uses become joined with each other across the middle line. The boundaries of the THE NERVOUS SYSTEM 
896 
opening are, above and in front, the anterior pillars of the fornix; behind, the 
anterior extremity of the optic thalamus. 
The Posterior Pillars of the Fornix (crura jornicis) are the backward prolongations 
of the two halves of the body of the fornix. They are flattened bands, and, at their 
commencement, are intimately connected by their upper surfaces with the corpus 
callosum. Diverging from one another, each curves round the posterior extremity 
of the optic thalamus, and then passes downward and forward into the descending 
horn of the lateral ventricle. Here it lies along the concavity of the hippocampus 
major, on the surface of which some of its fibres are spread out, the alveus, while 
the remainder are continued, as the fimbria, the corpus fimbriatum, the taenia 
fornicis or the taenia hippocampi (for it bears these different names) (Figs. 562, 
575, 577, and 583), into the hook or uncus of the hippocampal convolution. Fpon 
examining the under surface of the fornix, between its diverging posterior pillars, 
a triangular portion of the under surface of the corpus callosum may be seen. 
On it are a number of curved or oblique lines passing between the two pillars 
of the fornix. This portion has been termed the lyra or psalterium (Fig. 583), 
from the fancied resemblance it bears to a harp. It is also called the commissura 
hippocampi. In some cases there is a small space intervening between the lyra 
and the under surface of the corpus callosum known as Verga's ventricle. 
The Anterior Commissure of the Cerebrum (commissura anterior cerebri') (Figs. 580, 
584, and 587).-The anterior commissure of the cerebrum is a bundle of white fibres, 
in the anterior wall of the third ven- 
tricle, placed in front of the ante- 
rior pillars of the fornix, behind the 
rostrum of the corpus callosum, 
and resting upon the lamina ter- 
minalis. The anterior commissure 
connects the two hemispheres, and 
in vertebrates possessing a corpus 
callosum is an extremely import- 
ant structure. On transverse sec- 
tion it is oval in shape, its largest 
diameter being vertical in direction 
and measuring about one-fifth of 
an inch. Its fibres pass backward 
and downward through the globus 
pallidus and below the putamen 
on each side, from which point 
most of the fibres radiate to the 
cortex, but some go to the external 
capsule. The fibres of the an- 
terior commissure are divisible into two groups: 1. An anterior group (pars ante- 
rior or pars oljactor ia), the fibres of which join the limbic lobes and connect each 
limbic lobe to the olfactory tract of the opposite side. The fact that the pars 
anterior contains fibres from the olfactory tract of the opposite side may serve to 
explain the condition of crossed anosmia, e. g., where there is a lesion in one 
temporal lobe with a loss of smell in the olfactory area of the opposite side of the 
nose. 2. A posterior group (pars posterior or pars occipitotemporalis), the fibres 
of which pass to the cortex of the temporal lobe and of the lower part of the 
occipital lobe. 
The Septum Lucidum (septum pellucidum) (Figs. 574,586, and 587).-The septum 
lucidum is a thin, double, vertically placed partition, which forms the internal 
boundary of the body and anterior horn of the lateral ventricle. It consists of two 
distinct laminae, separated in part of their extent by a narrow chink or interval, 
a 
o 
-J 
J 
s 
u 
^NTEmon ^llars 
Fig. 580.-Anterior commissure, left half, viewed from above. 
(Testut.) THE HEMISPHERES OF THE CEREBRUM 
897 
called the fifth ventricle. It is a thin, semitransparent septum, attached, above, 
to the under surface of the corpus callosum; in front to the reflected portion of the 
corpus callosum; below it passes between the fornix and the posterior margin of 
the rostrum to terminate in the sub-callosal gyrus; posteriorly it is between the 
fornix and body of the corpus callosum, being attached to each. It is triangular 
in form, broad in front and narrow behind; its inferior angle corresponds with 
the upper part of the anterior commissure. The outer surface of each lamina is 
directed toward the lateral ventricle, and is covered by the ependyma of that 
cavity, while its medial surface bounds the cavity of the fifth ventricle (p. 889). 
Fifth Ventricle (cavum septi pellucidi).-The fifth ventricle was originally a part 
of the great longitudinal fissure, which was shut off by the union of the hemi- 
spheres in the formation of the corpus callosum above and the fornix below. 
Each half of the septum is therefore formed by the medial wall of the hemisphere, 
and consists of an internal layer of gray matter, derived from the gray matter of 
the cortex, and an external layer of white substance continuous with the white 
matter of the cerebral hemispheres. The fifth ventricle differs from the other 
ventricles of the brain, inasmuch as it is not developed from the cavity of the cere- 
Eminentia 1 
collateralis. J 
Hippocampus 
major. 
Fascia 
dentata. 
Uncinate 
convolution. 
Gray matter 
of the 
hippocampus. 
Uncinate 
process or 
uncus. 
Fig. 581.-Transverse section of the middle horn of the lateral ventricle. (From a drawing by 
Mr. F. A. Barton.) 
bral vesicles, it is not lined by ciliated epithelium but by altered pia mater, and 
it does not communicate with the general ventricular cavity; further, the fluid 
it contains is not cerebro-spinal fluid but is of the nature of lymph. 
The structures on the floor of the descending horn of the lateral ventricle will 
now be described. , 
The Hippocampus Major or Cornu Ammonis (Figs. 581 and 583) is a white emi- 
nence, about two inches in length, of a curved elongated form, extending through- 
out the entire length of the floor of the descending horn of the lateral ventricle. 
At its lower extremity it becomes enlarged, and presenting two or three rounded 
elevations with intervening depressions, it resembles the paw of an animal, and 
is called the pes hippocampi (digitationes hippocampi} (Fig. 583). If a transverse 
section is made through the hippocampus major, it will be seen that this eminence 
is produced by the folding of the cortex of the brain to form the dentate or hippo- 
campal sulcus (Figs. 562, 563, 564, and 567). The dentate fissure is separated 
from the choroid fissure by the dentate gyrus or dentate fascia fascia dentata} 
(Figs. 562 and 581). The hippocampal gyrus and the fifth temporal gyrus together 
constitute the uncinate convolution (Figs. 567 and 581). The uncus (Fig. 581) is the 898 
THE NERVOUS SYSTEM 
hook-like anterior extremity of the hippocampal or uncinate gyrus. To the outer 
side and parallel with the hippocampus major an elongated eminence, the 
eminentia collateralis, is frequently recognized (Fig. 581). It corresponds with 
the middle part of the collateral fissure, and its size depends on the direction and 
depth of this fissure. The main mass of the hippocampus major consists of gray 
matter, but on its ventricular surface is a thin layer of white matter, known as 
the alveus, which is continuous with the corpus fimbriatum of the fornix and 
is covered by the ependyma of the ventricle. Dr. J. G. Macarthy, of McGill 
University, Montreal, has shown1 that, if the alveus and superficial strata of gray 
matter be reflected from the surface of the hippocampus by an incision carried 
along its convexity, the "core" of the hippocampus, as he terms it, presents in 
many cases a corrugated or crimped appearance. 
The Corpus Fimbriatum, Taenia Fornicis, or Fimbria (taenia hippocampi or taenia 
fimbriae) (Figs. 562, 575, 577, and 583) has already been mentioned as a part of the 
posterior pillar of the fornix. It consists of a narrow white band, which is placed 
immediately below the choroid plexus, and is attached by its deep surface to the 
Fornix 
Optic thalamus 
Corpora guadrigemina 
Crus 
Fig. 582.-Diagram showing the mode of formation of the velum interpositum. 
white matter or alveus of the hippocampus major as it courses through the descend- 
ing cornu of the lateral ventricle. It can be traced as far as the uncus or hook of 
the hippocampal gyrus. Its inner margin is free, and rests upon the dentate fascia, 
from which it is separated by a slit-like fissure, the fimbrio-dentate fissure. The 
groove between the fimbria and the hippocampal convolution is the defile of the 
dentate fissure. Its outer margin is attenuated and irregular, and forms the line 
along which the ependyma is reflected over the choroid plexus as the latter is 
invaginated through the inferior part of the transverse fissure. When the choroid 
plexus is pulled away it carries the ependyma with it, and the descending horn 
opens on to the surface of the brain through the transverse fissure. If now 
the inner border of the corpus fimbriatum be raised, a notched band of gray 
matter, which is a free border of cortex, and is called the dentate fascia (jascia 
dentata hippocampi (Figs. 562 and 5S1), will be exposed; this has already been 
described as forming part of the limbic lobe (p. 879). 
1 Journal of Anat, and Phys., 1899, vol. xxiii. THE HEMISPHERES OE THE CEREBRUM 
899 
The Choroid Plexus (plexus chorioideus) (Figs. 548, 575, and 583) is a highly 
vascular, fringe-like structure, which is situated partly in the body and partly in 
the descending cornu of the lateral ventricle. It will be desirable to consider these 
two portions separately, in order to get a just conception of how they are formed. 
The portion in the body of the ventricle is the vascular, fringed border of a 
triangular fold of pia mater, the velum interpositum (tela chorioidea superior or tela 
chorioidea ventriculi tertii), which lies on the under surface of the fornix and forms 
the roof of the third ventricle. The developing brain vesicles are covered by pia 
mater. As the prolongation from the first vesicle, which is to form the cerebral 
hemispheres, increases in size, it grows backward and downward and covers the 
other vesicles, with the result that the pia mater covering the hemisphere comes in 
Fig. 583.-The fornix, velum interpositum, and middle or descending cornu of the lateral ventricle. 
contact with that covering the upper surface of the second vesicle. Portions of the 
two layers which are in contact form the velum interpositum. Immediately above is 
the body of the fornix, which is formed by the fusion of the cerebral hemispheres in 
the middle line, and below is the cavity of the second vesicle (the third ventricle), 
with the optic thalamus on either side. Just beyond the free lateral border of the 
fornix, between it and the taenia semicircularis, is a portion of the first cerebral 
vesicle, which is not developed into nervous matter, but is made up only of epen- 
dyma covered by pia mater. The vessels of this portion of the highly vascular pia 
mater become dilated and prolonged, and grow into the ventricle, pushing the 900 
THE NERVOUS SYSTEM 
ependyma before them, and forming an irregular congeries of vessels, apparently 
encroaching on the cavity of the lateral ventricle, but in reality being external to it, 
because they are separated from it by the lining membrane of the cavity, the 
ependyma. This vascular structure is the choroid plexus of the body of the ventricle. 
The part of the choroid plexus seen in the descending cornu is formed in 
exactly the same way-viz., by an ingrowth of the vessels of the pia mater into the 
cavity, pushing the ependyma before it, at a part of the wall of the horn where 
there is a similar absence of nervous tissue and where it consists simply of pia 
mater and ependyma in close contact. This portion lies between the corpus fim- 
briatum in the floor and the taenia semicircularis in the roof of the descending 
horn. This area, destitute of nervous matter, is continuous with the area in the 
body of the ventricle, from which the choroid plexus of this region originated, and 
in it the vessels of its pia mater increase, and, invaginating the ependyma, appear 
in the descending horn as its choroid plexus. In the body of the ventricle the 
choroid plexus is really the vascular fringed margin of the velum; beyond the pos- 
terior margin of the velum the plexus of the descending horn is continuous with 
the pia mater on the surface of the gyrus hippocampi; the two portions of the 
plexus are, however, directly continuous with each other, and constitute the 
choroid plexus of the lateral ventricle (plexus chorioideus ventriculi lateralis'). The 
gap or cleft through which the invagination of the pia mater takes place is called 
the choroid fissure. 
In front the choroid plexus of the lateral ventricle is small and tapering, and 
communicates with the plexus of the opposite side through the foramen of Monro. 
In structure it consists of minute and highly vascular villous processes, contain- 
ing an afferent and efferent vessel, and covered by a single layer of flattened epi- 
thelium, the cells of which often contain yellowish fat molecules. The anterior 
choroidal artery is derived from the internal carotid, and enters the ventricle at the 
extremity of the descending cornu, and, after ramifying in the plexus, sends 
branches into the adjacent parts of the brain. The posterior choroidal arteries, 
one or two in number on each side, are derived from the posterior cerebral artery, 
and reach the plexus by passing forward under the splenium of the corpus cal- 
losum. The veins of the choroid plexus unite to form a prominent vein, the choroid 
vein, which courses from behind forward to the foramen of Monro. On each 
side of the foramen of Monro a deep cerebral vein or vein of Galen is formed by 
the union of the choroid vein and the vein of the corpus striatum. The veins of 
Galen pass back in the velum interpositum, unite to form the common vein of 
Galen or the vena magna Galeni (v. cerebri magna), which empties into the straight 
sinus (p. 735). 
The Transverse Fissure or Fissure of Bichat (fissura cerebri transversa), separates 
the cerebrum from the cerebellum. This fissure passes forward and ends in the 
cerebrum as the lateral part of the transverse fissure or the choroid fissure (fissura 
chorioidea). The posterior part of the transverse fissure is occupied by the 
tentorium. Posteriorly the transverse fissure has above it the mass of the 
cerebral hemisphere and below it the upper surface of the cerebellum, the cor- 
pora quadrigemina, and the pineal gland. The transverse fissure is a complete 
fissure, but it is filled by the invagination of the pia mater, forming laterally 
the velum interpositum and the choroid plexuses, which invagination is covered 
by the lining of the ventricular cavities. If this involution of pia mater is pulled 
out, the ventricular lining will necessarily be torn away with it, and a cleft-like 
space will be left on either side, extending from the foramen of Monro to the 
bottom of the descending horn of the lateral ventricle. The upper part of the 
cleft, that is to say, the part nearest the foramen of Monro, is between the lateral 
border of the body of the fornix and the optic thalamus; below this, at the com- 
inencement of the middle horn, it is between the commencing corpus fimbriatum THE INTER-BRAIN 
901 
of the fornix and the pulvinar of the optic thalamus; and lower still, .in the 
descending horn, between the corpus fimbriatum on the floor and the taenia 
semicircularis in the roof of the cornu. The course of the choroid fissure from 
the foramen of Monro is backward, downward, and forward, to near the apex 
of the temporal lobe. The choroid fissures of the two sides are continuous 
between the fornix and the roof of the third ventricle. 
The Velum Interpositum or Tela Chorioidea Superior (tela chorioidea ventriculi 
tertii) (Fig. 548) is a vascular membrane, and is a prolongation of the pia mater 
into the interior of the brain through the middle part of the transverse fissure. 
It is of a triangular form, and separates the under surface of the body and pos- 
terior pillars of the fornix from the cavity of the third ventricle. Laterally it covers 
the inner part of the upper surface of the optic thalamus. Its posterior border or 
base lies beneath the splenium of the corpus callosum above, and the optic thala- 
mus, the corpora quadrigemina, and pineal body below. The upper layer of the 
base is continuous with the pia mater of the occipital lobe, and the lower layer of 
the base is continuous with the pia mater of the dorsal aspect of the cerebellum 
and mid-brain. Its anterior extremity or apex ends just behind the anterior com- 
missure, where it receives the anterior extremities of the choroid plexuses, which 
are here united through the foramen of Monro, and are then prolonged back- 
ward on the under surface of the velum as the choroid plexus of the third 
ventricle (plexus chorwideus ventriculi tertii). The inferior layer of the velum which 
carries the choroid plexus of the third ventricle is called the superior choroid tela 
(tela chorioidea ventriculi tertii). The external portion of the inferior layer of the 
velum interpositum covers the inner half of the superior surface of the optic 
thalamus. In front the plexuses of the third ventricle lie close to the middle line, 
but diverge from each other behind. Each lateral margin of the velum inter- 
positum constitutes the choroid plexus of the corresponding lateral ventricle. It 
is supplied by the anterior and posterior choroidal arteries, already described. 
The veins of the velum interpositum, the venae Galeni (vv. cerebri internae), two 
in number, run between its layers, each being formed by the union of the vein 
of the corpus striatum (v. corporis striata) with the choroid vein (v. chorioidea). The 
venae Galeni unite posteriorly into a single trunk, the vena magna Galeni or the 
common vein of Galen (v. cerebri magna), which terminates in the straight sinus 
(Fig. 548). The portion of the pia mater prolonged over the lower half of the 
fourth ventricle is known as the tela chorioidea inferior quarti. It carries the 
choroid plexus of the fourth ventricle (plexus chorioideus ventriculi quarti.) 
II. The Inter-brain (Thalamencephalon). 
The inter-brain is the region of the third ventricle, and comprises the parts 
developed from the second cerebral vesicle, together with parts from that portion of 
the first vesicle which is not concerned in the formation of the cerebral hemispheres. 
The inter-brain is connected above and in front with the cerebral hemispheres; 
behind, with the mid-brain or mesencephalon. On its upper surface it is entirely 
concealed from view, as it is covered by those portions of the internal surfaces of 
the cerebral hemispheres which have fused together to form the corpus callosum 
and the fornix, and is separated from the latter by the two layers of pia mater 
which form the velum interposition. Inferiorly it reaches the base of the brain, 
forming the structures contained in the interpeduncular space. 
The Third Ventricle (ventriculus tertius) (Fig. 584).-The third ventricle is 
the cavity of the inter-brain; it is in the mid-line, is at a lower level than the lateral 
ventricles; and the epithelial layer of the ependyma from the lateral ventricles 
is prolonged into the third ventricle through the foramen of Monro. The third ven- 902 
THE NERVOUS SYSTEM 
tricle contains cerebro-spinal fluid. It is a narrow median crevice between the two 
optic thalami, which constitute the side walls of the inter-brain. It is "about an 
inch in length from before backward and one-quarter of an inch broad at its 
widest part."1 Its roof is formed by the velum interpositum, from which is sus- 
pended the choroid plexus of the third ventricle. Its floor, somewhat oblique in 
its direction, is formed, from before backward, by the tuber cinereum, with its 
infundibulum and pituitary body; the corpora albicantia; the posterior perforated 
space; and the tegmenta of the crura cerebri. Its sides are formed by the optic 
thalami, and are limited above by a delicate band of white fibres, the pineal stria 
(stria medullaris thalami), which runs along the junction of the mesial and upper 
Fig. 584.-The third and fourth ventricles. An arrow has been placed in the position of the foramen of Monro. 
surfaces of the optic thalamus to join the anterior pillars of the fornix. Its sides 
are somewhat convex, so that in the middle of the ventricle the two lateral walls 
are almost in contact, and are here united across the middle line by a band of gray 
nervous matter, the middle, gray, or soft commissure (Fig. 584). The ventricle is 
bounded in front by the anterior pillars of the fornix and the lamina cinerea; behind 
by the pineal gland, the posterior commissure, and the upper end of the aqueduct 
of Sylvius, the iter a tertio ad quartum ventriculum. The cavity is much deeper in 
front than behind, and presents a recess at its anterior part, which lies over the optic 
commissure and is, therefore, termed the optic recess (recessus opticus). Behind 
and below this is the conical depression of the infundibulum (Fig. 587), passing 
1 Anatomy of the Brain and Spinal Cord. By Harris E. Santee. THE INTER-BRAIN 
903 
downward and forward to the pituitary body. At its posterior extremity the 
cavity forms another and smaller recess, which extends into the stalk of the 
pineal gland, and is termed the pineal recess (recessus pinealis). The anterior 
part of the third ventricle is called the aula. At the upper and anterior part of 
the third ventricle, immediately behind the anterior pillars of the fornix and in 
front of the optic thalamus, is an opening, the foramen of Monro (foramen inter- 
ventriculare [Monroty, by which this ventricle communicates with the lateral 
ventricle on either side (Figs. 548, 574, 575, and 587). The foramen of Monro 
opens into each lateral ventricleat the point of junction of the anterior horn and 
the body of the ventricle. It lies between the anterior pillar of the fornix and the 
anterior margin of the optic thalamus and ends by opening into the anterior and 
superior extremity of the third ventricle. Running back from the foramen of 
Monro toward the aqueduct of Sylvius is a furrow called the sulcus of Monro 
(sulcus hypothalamicus 1 Monroz]). At the posterior part of the floor of the third 
ventricle, beneath the posterior commissure, is the opening of the aqueduct of 
Sylvius or iter a tertio ad quartum ventriculum (Fig. 587), the channel which joins 
the third and fourth ventricles (p. 912). The roof of the cavity of the third ventricle 
is limited in front and behind by transverse bands of white matter, known 
respectively as the anterior and posterior commissures. The former has already 
been described in connection with the corpus striatum (p. 896). 
The Middle, Gray, or Soft Commissure (massa intermedia or commissura mollis) 
(Fig. 584).-The middle, gray, or soft commissure consists almost entirely of 
gray matter. It connects the two optic thalami, and is continuous with the 
gray matter lining the anterior part of the third ventricle. It is frequently 
broken in examining the brain, and might then be supposed to be wanting; it is 
sometimes double. 
The Posterior Commissure (commissura posterior) (Figs. 584 and 587.-The poste- 
rior commissure is a rounded band of white fibres, which stretches across from one 
optic thalamus to the other, overlying the upper end of the aqueduct of Sylvius. 
It is usually described as belonging to the inter-brain, but would appear to 
belong in part to the mid-brain, since some of its fibres are commissural and 
connect the anterior corpora quadrigemina to the fillet of the opposite side (see 
below). In addition there are other decussating fibres, which come from the 
tegmentum of the crus cerebri on one side and decussate with those of the 
opposite side in the posterior commissure, and passing through the optic 
thalamus reach the cerebral hemispheres. Fibres have also been described as 
taking their origin in the pineal body and ganglion habenulae, and passing across 
to the posterior longitudinal bundle and oculomotor nucleus of the opposite side; 
these fibres occupy the ventral part of the commissure, and receive their myelin 
sheath before those in its dorsal part. But to a certain extent the posterior com- 
missure belongs to the inter-brain, since it contains fibres which serve as com- 
missural fibres between the two optic thalami. 
The Optic Thalamus (thalamus) (Figs. 576,577, 578, 579, 580, 582, and 584). 
-The optic thalami are two large oblong masses, situated on either side of the third 
ventricle, and lying between the diverging portions of the corpora striata. They are 
composed mainly of gray matter, but the free surface of each is coated with a thin 
layer of white nervous tissue, the stratum zonale. They present outer and under 
surfaces, which are not free, but are blended with contiguous parts of the brain, 
and upper, inner, and posterior surfaces, which are free. The anterior extremity 
is narrow, and forms the posterior boundary of the foramen of Monro. The outer 
surface is in contact with the posterior limb of the internal capsule, which sepa- 
rates it from the lenticular nuclues. The inferior surface rests upon and is con- 
tinuous with the tegmentum of the crus cerebri. Its upper surface is free, and 
is separated from the caudate nucleus by a furrow which lodges the vein of the 904 
THE NERVOUS SYSTEM 
corpus striatum, and the taenia semicircularis. It is divided into an outer and an 
inner part by a groove which runs from behind, forward, and inward. The outer 
part forms a portion of the floor of the lateral ventricle, and is covered by the 
ependyma of that cavity; it terminates in front in a tubercle, the anterior tubercle 
of the optic thalamus (tuberculum anterius thalami). The inner part is covered by 
the velum interpositum, which separates it from the fornix, and is excluded from 
both the lateral and third ventricles by the reflection of the lining of these cavities, 
and is therefore destitute of an ependymal covering. 
The internal surface forms the lateral wall of the third ventricle, and running 
along its upper border is the peduncle of the pineal gland, from which the ependyma 
of the third ventricle is reflected on to the under surface of the velum interpositum. 
The shelf-like edge of the ependyma separates the superior from the internal 
surface of the thalamus. The edge is called the taenia thalami, and close to it is a 
narrow band of longitudinal fibres called the pineal striae {striae medullar is thalami). 
The taenia thalami and the pineal striae pass backward and then inward into the 
stalk of the pineal gland. The portion of the taenia which turns inward has pos- 
terior to it a small triangular depression called the trigone of the habenula (trigonum 
habenulae). This depression is just in front of the superior quadrigeminal body. 
Passing in a medial direction from the trigonum habenulae is a collection of 
white fibres, the habenula. The fibres of the anterior portion of this band are 
continuous with those of the opposite side, and constitute the commissure of the 
habenula {commissura habenularum). The fibres of the posterior portion consti- 
tute the peduncle of the pineal gland (p. 906). The posterior surface projects 
beyond the level of the corpora quadrigemina, and forms a well-marked rounded 
prominence, the posterior tubercle or pulvinar. The pulvinar is continued exter- 
nally into a second eminence, the external geniculate body (corpus geniculatum 
laterale), which is placed above and to the outer side of the internal geniculate body 
(corpus geniculatum mediale), and from which it is separated by the superior 
brachium, one of the roots of the optic tract. 
The optic or free upper surface of the thalamus is covered by white fibres derived, 
in part, at least, from the optic tract and radiation. The thalamus is formed chiefly 
of gray matter, which is arranged in three masses partially separated from each 
other by white matter called the internal medullary lamina (lamina medullaris 
interna), which is named internal in contradistinction to a second or external 
medullary lamina (lamina medullaris externa), which coats the outer surface of the 
thalamus and lies between it and the internal capsule. These masses of gray 
matter are the nuclei of the optic thalamus. Twenty nuclei have been described 
(Nissl). The chief nuclei are the following: 
1. The External or Lateral Nucleus (nucleus lateralis thalami).-The external or 
lateral nucleus, the largest of the nuclei, between the external and internal medul- 
lary laminae and extending the entire length of the thalamus, including, as Prof. 
Cunningham points out, the entire pulvinar, most of the tegmental fibres, and one- 
fifth of the optic fibres, terminate in this nucleus, and from it originate the fibres 
of the thalamic radiation. 
2. The Middle or Internal Nucleus (nucleus medialis thalami).-The middle or 
internal nucleus is separated by the internal medullary lamina from the other gray 
nuclei of the same side. It joins the middle nucleus of the opposite thalamus by 
means of the middle commissure. 
3. The Anterior Nucleus (nucleus anterior thalami).-The anterior nucleus is in 
the anterior tubercle, and in it terminate the fibres of the bundle of Vicq d'Azyr 
which come from the corpus mamillare (Fig. 586). 
In the substance of the thalamus are two other distinct nuclei, (4) the central 
nucleus of Luys and (5) the nucleus arcuatus. The nucleus or ganglion of the habenula 
lies in the trigonum habenulae. THE INTER-BRAIN 
905 
Connections of the Optic Thalamus (Figs. 586, 589, and 590).-The optic thalamus 
is a ganglion interposed between the sensory tracts in the tegmentum and the cere- 
bral cortex, being connected also with the optic tract. In this ganglion or in the 
adjacent ganglia of the subthalamic region, " almost every impulse of general sen- 
sation, on its journey to the cerebral cortex, is transferred to a higher neurone."1 
The crusta of the crus cerebri is external to the optic thalamus and passes into 
the internal capsule. The tegmental fibres of the crus (Fig. 586) pass to the under 
surface of the thalamus, and the forward prolongation of the tegmentum which 
becomes continuous with the under surface of the thalamus is called the sub- 
thalamic region, and most of the longitudinal fibres enter this ganglion, some of 
them terminating in it, some of them traversing it and entering the internal 
capsule. The internal capsule (Figs. 578, 589, and 590) is composed of fibres going 
to and coming from the cerebral cortex. Most of these fibres are descending ami 
form the crus cerebri. From all over the external surface of the optic thalamus 
fibres emerge, pass into the internal capsule, and from there go to the cerebral 
cortex. These fibres constitute the thalamic radiation. 
The nuclei of the thalamus have been described (p. 904). The white matter 
receives the fibres of the tegmentum and fillet, the majority of which enter the 
lateral nucleus; it receives fibres (axones) from the entire cerebral cortex and 
sends fibres to the cortical special sense areas of sight, hearing, and smell and 
to the area of general sensation) the somaesthetic area). 
The following groups of fibres of white matter are found in the thalamus: 1. 
The anterior pillar of the fornix, which passes through the inner part of the optic 
thalamus on its way to the corpus mamillare, and the bundle of Vicq d'Azyr, 
(fasciculus thalamomamillaris) (Fig. 586), which arises in the corpus mamil- 
lare and ascends to the anterior gray nucleus. 2. Two bundles of fibres emerging 
from the external surface of the thalamus. The superior bundle (ansa lenticu- 
laris) arises largely in the lateral nucleus, passes through the internal capsule and 
the lenticular nucleus; it then enters the external capsule, and passes to the 
insula, the paracentral lobule, the superior frontal convolution, and "the entire 
limbic lobe"2 (Fig. 589). The inferior bundle (ansa peduncularis) arises in the 
lateral nucleus, passes through the internal capsule below the lenticular nucleus, 
"enters into both the medullary laminae of that nucleus and the external capsule. 
It ends chiefly in the cortex of the ascending frontal and ascending parietal 
convolutions "3 (Fig. 589). These fibres constitute the ventral or inferior stalk 
of the thalamic radiation. 3. The anterior stalk of the thalamic radiation (Figs. 588 
and 590) arises in the lateral nucleus, passes to the frontal portion of the 
internal capsule, and reaches the inferior and middle frontal convolutions, 
the anterior portion of the superior frontal convolution, and the middle of the 
gyrus fornicatus (Santee), and is called the optic radiation (radiatio occipito- 
thalamica). The anterior stalk of the thalamic radiation, plus the ansa lenticularis 
and the ansa peduncularis, constitutes the cortical fillet or the three systems of 
Flechsig (p. 915). 4. The posterior stalk of the thalamic radiation (Fig. 590). 
The afferent part arises in the pulvinar and the external geniculate body, passes 
through the internal capsule, and terminates in the occipital cortex. The 
efferent portion terminates in the superior quadrigeminal body. 5. The acoustic 
radiation (Fig. 590) arises about the internal geniculate body, passes through the 
internal capsule, and reaches the auditory region in the temporal cortex. 
The Pineal Body, Epiphysis Cerebri, Conarium, or Pineal Gland (corpus 
pineale) (Figs. 584 and 587).-The pineal body or gland, so named from 
its peculiar shape (pinus, a fir-cone), is a small reddish-gray body, conical in 
shape (hence its synonym, conarium), placed immediately above and behind the 
1 Anatomy of the Brain and Spinal Cord. By Harris E. Santee. 2 Ibid. 8 Ibid. 906 
THE NERVOUS SYSTEM 
posterior commissure and between the anterior corpora quadrigemina, on which 
it rests. It is covered by the velum interpositum, which intervenes between it 
and the splenium of the corpus callosum. It is an upgrowth from the second 
cerebral vesicle (hence the name epiphysis), and is at first hollow, but soon 
becomes solid and loses its connection with the ventricular cavity. It is 
retained in its position by a duplicature of pia mater, derived from the under 
surface of the velum interpositum, which almost completely invests it. The 
pineal gland is about four lines in length and from two to three in width at 
its base, and is said to be larger in the child than in the adult, and in the 
female than in the male. It is attached on either side by a flattened stalk 
or peduncle of white matter, the pedunculus conarii (habenula). This stalk 
consists of two laminae, upper and lower, separated by a little recess, the 
pineal recess (recessus pinealis). The lower lamina is prolonged into the pos- 
terior commissure. The upper divides into two strands, the peduncles of the 
pineal gland (striae pinealis); these extend on either side along the optic thalamus 
at the junction of its mesial and upper surfaces to the anterior pillars of the 
fornix, with which they blend. The two stalks join together at their posterior 
extremity, in front of the pineal gland, forming a sort of festoon, and the base of 
the gland is connected to their posterior margin at the point of junction. 
Structure.-The pineal gland consists of a number of follicles, lined by epithe- 
lium, and connected together by ingrowths of connective tissue. The follicles con- 
tain a transparent viscid fluid and a quantity of sabulous matter named brain sand 
(acervulus cerebri), composed of phosphate and carbonate of lime, phosphate of 
magnesia and ammonia, with a little animal matter. These concretions are almost 
constant in their existence, and are present at all periods of life. They are found 
upon the surface of the pineal body and occasionally upon its peduncles. 
Morphologically the pineal gland is regarded as the homologue of the structure 
termed the pineal eye of the lizards. In these reptiles the epiphysis cerebri is 
attached by an elongated stalk and projects through the parietal foramen. Its 
extremity lies immediately under the epidermis, and on microscopic examination 
presents, in a rudimentary fashion, structures similar to those found in the eyeball. 
III. The Mid-brain (Mesencephalon) (Figs. 557, 584, 585, 587). 
The mid-brain is the short and constricted portion of the brain which lies in 
the opening of the tentorium cerebelli (incisura tentorii) and which connects the 
pons Varolii with the inter-brain and hemispheres, and hence it is frequently 
called the isthmus cerebri (isthmus rhombencephali). It is developed from the 
third cerebral vesicle, the cavity of which becomes the aqueduct of Sylvius. 
It comprises the crura cerebri, the corpora quadrigemina, the geniculate bodies, 
and the Sylvian aqueduct. Its direction is from before backward and down- 
ward. In front and above it is continuous with the inter-brain; below with 
the pons. Its two surfaces are ventral and dorsal. They are free, but concealed: 
the ventral surface by the apices of the temporal lobes which overlap it; the dorsal, 
by the overhanging cerebral hemispheres. The ventral surface, when exposed by 
drawing aside the temporal lobes, is seen to consist of two cylindrical bundles of 
white matter which emerge from the pons and diverge as they pass forward and out- 
ward to enter the inner and under part of either hemisphere. They are the cerebral 
peduncles (crura cerebri), and between them is a triangular area, already described 
as part of the interpeduncular space (fossa interpeduncularis) (see pp. 884 and 885); 
near the point of divergence of the crura the roots of the third nerve are seen to 
emerge in several bundles from a groove, the sulcus oculomotorius (sulcus nervi 
oculomotorii) (Fig. 570). 'Phe dorsal surface (Fig. 584) is not visible until a con- 
siderable portion of the cerebral hemispheres and other overlying structures have THE MID-BRAIN 
907 
been removed. It then presents four rounded eminences placed in pairs, two in 
front and two behind, and separated from one another by crucial depression. 
These are termed the corpora quadrigemina (tubercula quadrigemina) (Figs. 584 and 
585). The ventral and dorsal surfaces meet on the side of the mid-brain, and 
are separated from each other by a furrow, the lateral groove {sulcus lateralis 
mesencephali), which runs from below upward and forward (Fig. 585). 
If a cross-section be made through the mesencephalon (Fig. 585), it will be seen 
that each lateral half is divided into two unequal portions by a lamina of deeply 
pigmented gray matter, named the substantia nigra. The postero-superior portion 
of the crus is named the tegmentum, and the antero-inferior the crusta or pes. The 
substantia nigra is curved on section with its concavity upward, and extends from 
the lateral groove externally to the oculomotor 
sulcus internally. The two crustae are in con- 
tact in front of the pons, from which point they 
diverge from one another, but the two halves of 
the tegmentum are joined to each other in the 
mesial plane by a prolongation forward of the 
raphe or median septum of the pons. Laterally 
the tegmenta are free, but dorsally they blend 
with the corpora quadrigemina. 
Crusta or Pes (basis pedunculi) (Fig. 585).- 
The crusta is known as the pes of the crus 
cerebri. The crustae are two in number, are 
semilunar on section, and are separated by the 
interpeduncular space (Fig. 570). From the front 
of the pons each crusta passes upward, forward, and outward, enters the cerebrum 
to the outer side of the thalamus, and its fibres enter and spread out in the internal 
capsule (Figs. 589 and 590). The great bulk of the fibres are limited to the superior 
lamina of the capsule. The deep portion of the crusta contains the intermediate 
bundle or tract (Fig. 590), the fibres of which rise in the corpus striatum and 
terminate in motor cranial nuclei and the nucleus pontis, and from this nucleus 
fibres pass by way of the middle peduncle of the cerebellum to the cortex of the 
opposite cerebellar hemisphere. 
The superficial portion of the crusta contains three sets of fibres (Figs. 589 
and 590): 1. The outer one-fifth is composed, according to Dejerine, of fibres 
which take origin in the cortex of the superior, middle, and inferior temporal 
convolutions, the cerebro-cortico-pontal tract (tractus cerebrocorticopontalis tem- 
poralis). They pass through the inferior lamina of the internal capsule and 
through a portion of the superior lamina, and mostly terminate in the nucleus 
pontis. Some few of these fibres terminate in the motor nuclei of the cranial 
nerves.1 2. The middle three-fifths, which is largely composed of motor fibres, 
is known as the pyramidal tract (fasciculus longitudinalis pyramidalis). These 
fibres take origin in the cells of the Rolandic area of the cortex, converge to 
the internal capsule, and pass down through its genu and through the ante- 
rior two-thirds of its posterior limb to the crusta, from which they are pro- 
longed as longitudinal fibres through the ventral portion of the pons and as 
the pyramid through the medulla. Below the medulla they pass into the direct 
and crossed pyramidal tracts of the spinal cord. The median portion of the 
pyramidal tract occupies the genu of the internal capsule and passes to the 
muscles of the face and the muscles of speech. 4416 fibres which pass to the arm 
muscles, in the crusta, are posterior and external to the fibres which go to the face. 
Behind and external to the arm fibres are the fibres to the muscles of the trunk 
C. Quadrigemina. 
Aqueduct 
Tegmentum. 
-Sub- 
I stantia 
| nigra. 
Interpeduncular space. 
Fig. 585.-Transverse section of the 
mid-brain. 
1 Spitzka; Santee. 908 
THE NERVOUS SYSTEM 
and leg. A few fibres from the cerebellum are placed among the pyramidal fibres. 
These fibres reached the pons by way of the middle cerebellar peduncle, ascend 
from the pons with the longitudinal fibres, and reach the crusta. 3. The inner 
one-fifth of the crusta is formed by the fibres of the median fillet (lemniscus 
medialis) and motor fibres coming from the cortex in front of the Rolandic fissure 
(from the prefrontal lobe). This tract from the prefrontal lobe descends through 
the anterior limb of the internal capsule and through the crusta and reaches the 
nucleus pontis, from which point it is connected by fibres with the cerebellar 
hemisphere of the opposite side. It is called the frontal cerebro-cortico-pontal tract 
(tractus cerebrocorticopontalis frontalis). The median fillet is composed of central 
sensory fibres from the spinal nerves and all the cranial nerves, except the 
cochlear branch of the auditory (Santee). It arises from the fillet, and at the 
lower part of the crusta is situated at the mesial border. As it ascends it courses 
obliquely outward to meet the lateral border of the pyramidal tract. It enters 
the sub-thalamic region, and ends in the lateral nucleus of the optic thalamus. 
Some of the fibres of this tract reach the cortex by joining the ansa peduncularis 
and the ansa lenticularis. 
The Tegmentum (Fig. 585).-The tegmentum (the cover) is that portion of the 
mid-brain which is superior to the substantia nigra and covers the two crustae 
and the substantia nigra. Its ventral surface is placed within the concave sur- 
face of the substantia nigra. The internal geniculate bodies and the corpora 
quadrigemina are upon its dorsal surface. The anterior extremity of the 
tegmentum enters the optic thalami, and the posterior extremity is continued 
into the pons. The tegmentum contains the aqueduct of Sylvius (p. 912 and 
Figs. 585 and 587). 
Fibres of the Tegmentum (Fig. 590).-The pontine formatio reticularis, the gray 
matter of the floor of the fourth ventricle, and the longitudinal fibres of the dorsal 
portion of the pons are continued and compose the tegmentum, which structure 
has upon its dorsal aspect the geniculate and quadrigeminal ganglia. Each half 
of the tegmentum consists of strands of longitudinal white fibres separated from 
each other by transversely arched fibres. There is also a considerable quantity of 
gray matter. The peculiarly reticulated structure formed by the gray and white 
matter is named the formatio reticularis, and is similar to the structure met with in 
the pons and medulla, with which it is continuous. 
The Red Nucleus of the Tegmentum (nucleus tegmenti) (Fig. 589).-The red nucleus 
of the tegmentum is a tract of gray matter situated partly in the tegmentum and 
partly in the subthalamic tegmental region on either side of the middle line. It is 
composed of numerous large cells which are deeply pigmented. It is pierced by 
the fibres of the third nerve. The red nucleus sends fibres to the corpus dentatum 
by means of the opposite superior peduncles of the cerebellum, and also gives 
off the crossed descending tract. The nucleus of Luys (nucleus hypothalamicus) 
is above and external to the red nucleus and between it and the crusta. It 
receives fibres from the median fillet and from the corpus striatum, and is con- 
nected by fibres to the lamina cinerea and tuber cinereum, which are known as 
the commissure of Meynert (Santee). 
The longitudinal fibres in some parts of the tegmentum are arranged in six 
fairly well-defined tracts, which are described as follows by Harris E. Santee in 
the Anatomy of the Brain and Spinal Cord: 
1. The Posterior Longitudinal Bundle (fasciculus longitudinalis medialis) (Fig. 
586) is in large part an associated tract. It lies by the side of the raphe just below 
the aqueduct. These fibres ascend from the gray substance of the anterior cornu 
of the spinal cord. In the anterior column of the cord they probably form short 
longitudinal commissures between different segments of the cord. They ascend 
through the pyramid of the medulla, form the posterior longitudinal bundle of the THE MID-BRAIN 
909 
pons, and enter the tegmentum. The posterior longitudinal bundle, while travers- 
ing the pons, receives fibres from the cerebellum, and in the pons and medulla 
receives fibres from the sensory nuclei of cranial nerves. "It carries motor fibres 
from the sixth to the third nerve; also descending motor fibres from the nucleus 
of the motor oculi to the genu of the* seventh or facial nerve." Soon after entering 
the tegmentum the posterior longitudinal bundle decussates across the raph£ with 
the bundle of the opposite side. This constitutes the lower decussation, and the 
decussated fibres pass to the nuclei of the third, fourth, and other cranial nerves. 
The undecussated fibres ascend, and in the posterior commissure decussate. This 
is known as the upper decussation, and the fibres enter "the pineal body and 
stratum dorsale of the hypothalamic region. " 
Fig. 586.-The short tracts in the brain-stem and inter-brain. Sagittal section through the middle of the 
brain-stem: inf, infundibulum; c. mam, corpus mamillare; fasc. Vic, bundles of Vicq d'Azyr; f. tea, tegmental 
bundle; ped. m, peduncle of corpus mamillare; fasc. rt, fasciculus retroflexus; fasc. I. inf, posterior longitudinal 
bundle; II, III, VI, XII, corresponding cranial nerves; c, pineal gland. (Jakob.) 
2. The Anterior Longitudinal Bundle is composed of fibres which pass from the 
superior quadrigeminal body to the ciliary centre (dilator fibres of the pupil) and 
other centres in the spinal cord. 
3. The Fillet or Lemniscus is "a segment in the direct sensory tract. It 
carries spinal and cranial impulses to the corpora quadrigemina and optic 
thalamus." It takes its chief origin from the medulla, and passes through the 
formatio reticularis of the pons to the ventral.portion of the tegmentum, where it 
divides into two portions, the interolivary fillet and the lateral fillet. 
The interolivary fillet (lemniscus inter olivari s') arises from the opposite side of 
the medulla oblongata (from the nucleus gracilis and nucleus cuneatus), decus- 
sates with the sensory fibres, and terminates in the lateral nucleus of the thalamus. 
A bundle of fibres come off from the interolivary fillet soon after its origin and 910 
THE NEIIVOUS SYSTEM 
passes to the superior quadrigeminal bodies. This bundle is the upper or superior 
fillet (lemniscus superior). The interolivary bundle after giving off the superior 
fillet is known as the median or mesial fillet (lemniscus medialis or mesialis). It 
ascends, turns toward the ventral surface of the tegmentum, passes through the 
substantia nigra, and along the inner one-fifth of the crusta to the thalamus, and 
from the thalamus connection with the cortex is established by the ansa lenticularis 
and the ansa peduncularis. 
The lower or lateral fillet (lemniscus lateralis) arises almost entirely from the 
cochlear nuclei, and mostly from the opposite nucleus. It is situated in the ventral 
part of the tegmentum, through which it passes obliquely and emerges at its side, 
and after crossing the superior peduncle of the cerebellum, passes to the inferior 
quadrigeminal bodies. It is reinforced by some fibres from the superior medullary 
velum. It is a path in the conduction of auditory impressions. These impressions 
pass from the auditory nerve to the lateral fillet, from this to the inferior brachium, 
and then to the cortex by the acoustic radiation (Fig. 590). 
4. The Superior Peduncle of the Cerebellum (brachium conjunctivum) (Figs. 590 
and 599) ascends from the dorsal surface of the pons. It is connected to its fellow 
peduncle by a band of white matter called the valve of Vieussens (velum medullare 
anterius) (Fig. 584). The fibres of the superior peduncles of the cerebellum pass 
beneath the quadrigeminal bodies, and to a large extent decussate across the raph^ 
and below the Sylvian aqueduct. It is thus evident that the fibres from one-half 
of the cerebellum pass largely to the opposite half of the cerebrum. The numerous 
crossed and the few uncrossed fibres pass forward, enclosing the red nucleus (in 
which structure many of the fibres terminate and from which structure it obtains 
some fibres), and passes to the "stratum dorsale of the hypothalamic region." 
5. The Olivary Fasciculus (jasciculus tegmenti centralis) (Fig. 589) arises from 
the inferior olivary nucleus of the medulla, ascends through the medulla and 
pons to the tegmentum, passes through the decussation of the superior peduncles 
of the cerebellum, and ascends to the outer side of the posterior longitudinal 
bundle of tegmental fibres, to end in the lenticular nucleus. 
6. The Crossed Descending Tract arises in the red nucleus (Fig. 589), decussates 
with the opposite tract, enters the lateral fillet, reaches the medulla, where it 
"mingles with the antero-lateral ascending cerebellar tract," and passes into the 
pyramidal tract of the cord, to end in "the lateral horn and centre of the gray 
crescent." The nucleus of Luys (Fig. 589) is the anterior termination of the 
substantia nigra. 
The Substantia Nigra (Figs. 585 and 589).-This, as already stated, constitutes 
the central portion of the mid-brain. It is a layer of deeply pigmented gray matter, 
which separates the crusta below from the tegmentum above. It can be seen at 
the base of the brain between the crustae. In this region it is known as the posterior 
perforated lamina (substantia perforata posterior) (Fig. 570). In each lateral sulcus 
the edge of the substantia nigra reaches the surface (Fig. 585). The substantia 
nigra extends from the pons behind to the corpora albicantia and nucleus of Luys 
in front. It is thicker internally than externally, where it is partially divided up 
by the mesial fillet passing from the tegmentum to the crusta. It is traversed 
at its inner part by some of the fibres of origin of the third cranial nerve, which 
emerge from the motor oculi groove. 'The cells are small and multipolar, and are 
characterized by containing a large amount of dark pigment granules. 
The Interpeduncular Ganglion (ganglion interpedunculare) is just in front of the 
pons in the median line. Some fibres (the jasciculus retrojlexus) (Fig. 586) join 
this ganglion to the nucleus habenulae of the thalamus (Forel, Santee). In 
each half of the substantia nigra, laterally and anteriorly, is a nucleus known as 
the nucleus of Luys (nucleus hypothalamicus) (Fig. 589). The zona incerta sepa- 
rates the nucleus of Luys from the red nucleus of the tegmentum. THU MID-BRAIN 
911 
The Corpora or Tubercula Quadrigemina (Figs. 574, 584, 585,586, and 587).- 
Thecorpora or tubercula quadrigemina are four rounded eminences placed in pairs, 
two in front and two behind, and separated from one another by the crucial groove 
or depression. They are situated on the dorsal surface of the mid-brain, imme- 
diately behind the third ventricle and posterior commissure, and beneath the 
splenium of the corpus callosum. The anterior or upper pair (colliculi superiores), 
called the nates, are the larger. They are oval, their long diameter being directed 
forward and outward, and are of a gray color. The posterior or lower pair (col- 
liculi inferiores), called the testes, are hemispherical in form, and lighter in color 
than the preceding. From the outer side of each of these eminences a prominent 
white band, termed the brachium, is continued forward and outward. The band 
from the nates (brachium quadrigemin/um su perius) passes obliquely outward 
between the pulvinar and the inner geniculate bodies into the external geniculate 
body. The band from the testes (brachium quadrigeminum injerius) loses itself 
beneath an oval prominence on the side of the quadrigeminal body. This promi- 
nence is called the internal geniculate body. The corpora quadrigemina are larger in 
the lower animals than in man. In fishes, reptiles, and birds they are hollow, and 
only two in number (corpora bigemina); they represent the anterior quadrigeminals 
of mammals. In these lower animals the corpora bigemina are frequently termed 
the optic lobes, because of their connection with the optic tracts. In the mammalia 
the corpora are four in number, and solid. In the human foetus all four bodies 
are differentiated by the fifth month, and form at this time a considerable propor- 
tion of the brain. In man the anterior quadrigeminal bodies are sometimes called 
the optic lobes and the posterior bodies the auditory lobes. 
Structure.-The corpora quadrigemina are composed of white matter externally, 
and gray matter within. The posterior pair consist almost entirely of gray matter, 
covered over by a very thin stratum of white substance. Beneath the gray matter 
is a thin layer of white fibres, forming a part of the lower fillet. This separates 
the gray matter of the posterior corpora quadrigemina from the central gray 
matter of the aqueduct. The anterior pair are covered superficially by a thin 
stratum of white matter. The stratum zonale, the fibres of which are fine and 
arranged transversely. Beneath this is the stratum cinereum, a layer of gray 
matter which resembles a cup, semilunar in shape, thicker in the centre, and 
thinning off toward the margins, and consisting of numerous multipolar cells, for 
the most part of small size, embedded in a fine network of nerve-fibres. Below7 
this again is the stratum opticum or upper gray-white layer, characterized by the 
large amount of fine nerve-fibres which intersect the gray matter. These fibres 
vary in size in different parts of the layer, but have for the most part a longitudinal 
direction. The nerve-cells between the fibres are larger, and send their axis- 
cylinder processes into the next stratum. Finally there is the stratum lemnisci, 
or deep gray-white layer, which separates the rest of the quadrigeminal body from 
the gray matter around the aqueduct. It consists of fibres partly derived from 
the upper fillet and partly from the cells of the preceding layer. Interspersed 
among these fibres are nerve-cells of large size. 
The anterior quadrigeminal body contains an anterior layer of longitudinal 
fibres, which takes origin in close relation to the optic fibres and ends in the ciliary 
centre of the spinal cord. In the posterior quadrigeminal body the white fibres 
are continuous posteriorly with the lateral fillet, and are continuous laterally with 
the brachium. The anterior quadrigeminal bodies "associate optic fibres with 
the nuclei of the third, fourth, and sixth cranial nerves and with the cilio-spinal 
centre in the cervical cord" (Santee). The posterior bodies constitute "a way- 
station in the auditory conduction path" (Santee) (Fig. 590). 
The Corpora Geniculata.-The corpora geniculata are two small, oblong 
masses on each side, situated behind and beneath the posterior end of the optic 912 
THE NERVOUS SYSTEM 
thalamus, and named, from their position, external and internal geniculate bodies. 
These two bodies are separated from each other by the brachium anterius of the 
anterior quadrigeminal body. It is convenient and customary to describe these 
two bodies together, but the student should bear in mind that the corpus genic- 
ulatum externum belongs in reality to the optic thalamus; the corpus geniculatum 
internum, which is part of the tegmentum, alone belonging to the mid-brain. 
The External Geniculate Body (corpus geniculatum later ale) (Fig. 613).-The 
external geniculate body is of a dark color, and presents a laminated arrangement, 
consisting of alternate layers of gray and white matter. Its cells are large, multi- 
polar, and pigmented; their processes are intimately related with the visual area 
in the cerebral cortex of the occipital region (Fig. 590). It is believed that the 
intercellular gray matter of these bodies is composed, to a considerable extent, of 
the terminations of the optic nerve, which form synapses around the cells. About 
80 percent, of the optic fibres enter the external geniculate body (von Monokow, 
Santee). It is, in fact, the termination of the outer root of the optic tract. 
The Internal Geniculate Body (corpus geniculatum mediale) (Fig. 613).-The inter- 
nal geniculate body is the termination of the inner root of the optic tract. It seems 
FORAMEN 
OF MONRO 
ANTERIOR 
COMMISSURE 
CORPUS 
ALBICANSI 
IN FUN DI BU LUM 
-OPTIC NERVE 
POSTERIOR 
COMMISSURE 
HYPOPHYS'S 
Fig. 587.-Median section through the third and fourth ventricles, left half. M.C., middle commissure. (Testut.) 
to receive some of the fibres of the optic tract and is "a way-station in the auditory 
tract" (Santee). It is smaller in size and lighter in color than the external genicu- 
late body, and does not present a laminated arrangement. It receives the pos- 
terior brachium from the inferior quadrigeminal body. The internal geniculate 
bodies are connected with each other through the optic commissure by a band 
of intercerebral fibres of the optic tract named Gudden's commissure. The anterior 
quadrigeminal body, the pulvinar, and the external geniculate body are intimately 
concerned with vision. They constitute the lower cerebral centre for the optic 
nerve-fibres which end in them. Extirpation of the eyes in newly born animals 
entails an arrest of their development, but has no effect on the posterior quadri- 
geminal body or the internal geniculate body. These latter also are well developed 
in the mole, in which animal the superior quadrigeminal body is rudimentary. 
The Aqueduct of Sylvius or Iter a Tertio ad Quartum Ventriculum (aquae- 
ductus cerebri) (Figs. 574, 584, 585, and 587).-This is a narrow canal, about THE MID BRAIN 
913 
half an inch in length and from one-sixteenth to one-eighth of an inch in height, 
situated between the corpora quadrigemina and the tegmentum, and connecting 
the third with the fourth ventricle. Its shape on transverse section varies, being 
T-shaped below, triangular above, and oval about the middle of its course. It 
is lined by columnar ciliated epithelium, and is surrounded by a layer of gray 
matter, called the central gray matter of the aqueduct, which is continuous with 
the gray matter of the third and fourth ventricles. This gray matter is sepa- 
rated above from that of the corpora quadrigemina by the stratum lemnisci; 
below the central gray matter lie the posterior longitudinal bundle and the 
formatio reticularis of the tegmentum. The central gray matter is more abun- 
dant below the canal than above it. In the gray matter are certain defined groups 
of cells, which are the nuclei of the third and fourth cranial nerves. 
Subthalamic Region.-One other structure, to which allusion has already 
been made, requires mention in this connection; it is the subthalamic region. It is 
a prolongation forward of the tegmentum of the crus cerebri, which becomes con- 
tinuous with the lower surface of the optic thalamus. Toward the anterior part 
of the crus cerebri the tegmentum becomes thinned out, and is blended with the 
superjacent portion of the optic thalamus. To this region, the name subthalamic 
tegmental region has been given. In front it is lost at the base of the brain in 
the gray matter of the anterior perforated space, and is continuous with the gray 
matter of the floor of the third ventricle. The subthalamic tegmental region con- 
tains a forward prolongation of the red nucleus, and consists from above down- 
ward of three layers: (1) stratum dorsale, which is directly applied to the under 
surface of the optic thalamus, and consists of fine longitudinal fibres; (2) the zona 
incerta, a continuation forward of the formatio reticularis of the tegmentum; and 
(3) the corpus subthalamicum or the nucleus of Luys (nucleus of Luys or nucleus 
hypothalamicus), a mass of gray matter which on section presents a lenticular 
shape, and is the termination of the substantia nigra. 
Structure of the Cerebrum.-The cerebrum, like the other parts of the great 
nerve centre, is composed of gray and white matter. In order to give some general 
idea of its construction, at all events in part, it may be compared, for the sake of 
illustration, to a tree, the trunk of which divides into two main divisions, and 
these break up into smaller branches, which finally end in twigs, to which are 
attached the leaves, forming an investment to the branches and covering the whole 
tree. The trunk is represented by the medulla oblongata as it passes through the 
foramen magnum; the two main divisions by the crura cerebri, which break up 
into smaller branches; these diverge from each other, divide and subdivide, 
until they reach the surface of the hemispheres, where they terminate in single 
nerve-fibres, which are continuous with the basal axial cylinder processes of the 
nerve-cells, the representatives of the leaves. These cells are arranged on the 
surface, covering the hemispheres like a cap, and constitute the cerebral cortex. 
But here the analogy ends, for in the cerebrum there are, in addition to this 
cortex, other masses of gray matter situated in the middle of the brain; and 
other white fibres besides the diverging ones that have been mentioned, and which 
serve either to connect the two cerebral hemispheres, or to unite different structures 
in the same hemisphere. 
The White Matter of the Cerebrum.-The white matter-of the cerebrum con- 
sists of medullated fibres, varying in size and arranged in bundles, separated 
by neuroglia. They may be divided into three distinct systems, according to 
the course they take. 1. Projection or peduncular fibres (Figs. 588, 589, and 590), 
which connect the hemisphere with the medulla oblongata and cord. 2. Trans- 
verse or commissural fibres (C.C. in Fig. 588), which unite together the two 
hemispheres. 3. Association fibres (Figs. 591 and 592), which connect different 
structures in the same hemisphere. Many of the association fibres are collateral THE NERVOUS SYSTEM 
914 
branches of the projection fibres, but others are the axones of independent 
cells. 
1. The Projection or Peduncular Fibres (Figs. 588, 589, and 590) are either cen- 
trifugal (motor) or centripetal (sensory), and they connect the cerebral cortex with 
every portion of the body, and either project impulses from the cortex to every por- 
tion of the body or bring impressions from all parts to the cortex. The basal ganglia 
intercept many projection fibres, 
especially centripetal fibres. 'The 
projection fibres are composed first 
of the "medullated axis-cylinders 
of the large and medium-sized pyr- 
amids and a few of the polymor- 
phous neurones in the cerebral cor- 
tex; and second, of medullated ax- 
ones of neurones whose centres are 
situated in masses of gray matter 
below the cerebral cortex."1 These 
fibres form in the hemisphere the 
corona radiata and the internal 
capsule, and in the mid-brain the 
crus. The fibres of the crus are 
arranged in two strata, the ventral 
or superficial stratum or crusta and 
the dorsal or deep stratum or teg- 
mentum. Between the two strata 
is the substantia nigra. 
The Centrifugal or Motor 
Projection Fibres.-Most of 
the motor fibres are included in 
the crusta. The deep portion of 
the crus is composed of the inter- 
mediate bundle or tract (p. 907), 
and the superficial portion of the 
crus is composed of three sets of fibres (p. 907): 1. The temporal cerebro-cortico- 
pontal tract (tractus cerebrocorticopontalis temporalis), occupying the outer one- 
fifth of the crus. 2. 'The pyramidal tract fasciculus longitudinalis pyramidal is), 
occupying the middle three-fifths of the crus. These fibres pass to the pyramid 
of the medulla and to the direct and crossed pyramidal tracts of the spinal 
cord A few fibres from the cerebellum are placed among the pyramidal fibres. 
They reach the pons by way of the middle cerebellar peduncle, ascend from the 
pons with the longitudinal fibres, and reach the crusta. 3. The inner one- 
fifth of the crusta is formed by the median fillet and motor fibres coming from 
the cortex in front of the Rolandic fissure. The tegmentum contains some few 
motor fibres arranged in several bundles-viz., the anterior longitudinal bundle, 
a portion of the superior peduncle of the cerebellum: the descending or motor 
root of the fifth nerve, the crossed descending tract from the red nucleus. To 
these previously mentioned motor fibres in the tegmentum, Santee adds "certain 
fibres in the formatio reticularis."2 
'The Centripetal or Sensory Projection Fibres.-In the tegmentum are 
the sensory fibres, some of the fibres of the formatio reticularis, some of the fibres 
of the posterior longitudinal bundle, the fillets, most of the fibres of the superior 
cerebellar peduncle, the outer root of the optic tract, and the olivary fasciculus. 
Nearly all of the bundles terminate in the basal ganglia, "but the paths of con- 
Fig. 588. - Section through the frontal lobe, showing the be- 
ginning of the most anterior bundles of the corona radiata, 
which contain the first fibres of the pyramidal tract (R). C. C., 
corpus callosum; C. F., centrum semiovale Vieussenii; C. .4., 
anterior limb of the internal capsule; F. I., inferior frontal con- 
volution (base of the third frontal convolution-motor speech 
centre). (Jakob.) 
1 Anatomy of the Brain and Spinal Cord. By Harris E. Santee. 2 Ibid. THE MID-BRAIN 
915 
duction are continued through the internal capsule" (Santee). In the internal 
capsule the sensory projection fibres comprise the three systems of Flechsig (the 
cortical fillet), the optic radiation, 
and the acoustic radiation. 
The Three Systems of Flech- 
sig.-The chief origin of the three 
systems of Flechsig is in the lateral 
nucleus of the thalamus. The first 
system of Flechsig is composed of 
fibres of common sensation and is 
called the ansa peduncularis. It 
passes from the thalamus to the 
cortex of the ascending frontal and 
parietal convolutions. The fibres of 
this first system are in the inferior 
lamina of the internal capsule, and 
are posterior to the pyramidal tract. 
Some fibresof the ansa peduncularis 
pass through the lenticular nucleus, 
others pass through the external 
capsule, but all of them terminate 
as do those in the internal capsule, 
in the cortex. The second system of 
Flechsig is called the ansa lenticularis. 
Its fibres convey impressions of com- 
mon sensation. It arises from the 
thalamus at a higher level than the 
ansa peduncularis, and in the in- 
ternal capsule its fibres are among 
the pyramidal fibres. It terminates 
in the cortex about the central con- 
volution, the superior frontal con- 
volution, the paracentral lobule, and 
the limbic lobe. Some fibres pass 
through the internal capsule to the 
lenticular nucleus and aid in form- 
ing the external capsule. The third 
system of Flechsig is the anterior 
stalk of the thalamic radiation. It 
arises in the thalamus, passes to the 
frontal portion of the internal cap- 
sule, and reaches the inferior, mid- 
dle, and superior frontal convolu- 
tions and the gyrus fornicatus. The 
third system also conveys common 
sensory impressions. 
The optic radiation (D in Fig. 590) 
takes origin in the pulvinar of the 
thalamus and in the internal corpus 
geniculatum. The fibres pass back of the lenticular nucleus and reach the cortex 
of the cuneate lobe, in which region the corresponding half of each retina is 
represented. 
The acoustic radiation (D in Fig. 590) with the inferior brachium from the 
inferior quadrigeminal body, according to Barker, constitute the continuation of 
Fig. 589.-Scheme of the projection fibres of the cerebral 
cortex. Cc. Corpus callosum. Cr. Internal capsule, into 
which fibres pass from the cortex above the Sylvian fissure. 
NC. Caudate nucleus. N L. Lenticular nucleus. Th. Optic 
thalamus, in which many fibres from all parts of the cortex 
end. Cip. Posterior division of the internal capsule (the sen- 
sory tract). Cisl. Sublenticular part of the interna) capsule, 
containing fibres of auditory tract and fibres to the thalamus 
from the cortex below the Sylvian fissure. CL. Luys's body. 
NR. Red nucleus of tegmentum. Ln. Locus niger. VP. 
Tract from capsule to pons. Po. Pons. NP. Gray matter 
of pons. Oi. Olive. Py. Pyramidal tract in medulla, passing 
to FPyd, anterior median column of cord, and to FPyc, 
lateral column of cord of opposite side, and to fPyh, lateral 
column of cord of same side. B. Medulla. (Dejerine, Anat- 
omic des Centres Nerveux, vol. ii. p. 2.) THE NERVOUS SYSTEM 
916 
the auditory path "from the end of the lateral fillet, in the inferior quadrigeminal 
body, to the internal geniculate body, and then, through the retro-lenticular part of 
the internal capsule, to the transverse temporal gyri and the third and fourth 
fifths of the superior temporal convolution.''1 
2. The Transverse or Commissural Fibres (Figs. 572, 573, and C.C. in Fig. 588) 
connect the two hemispheres. They include: (a) the transverse fibres of the 
corpus callosum (p. 886); (6) the anterior commissure (p. 896); (c) the posterior 
commissure (p. 903), and have already been described. 
Fig. 590.-The projection tracts joining the cortex with lower nerve centres. Sagittal section, showing the 
arrangements of tracts in the internal capsule. A, tract from the frontal lobe to the anterior half of the capsule, 
thence in part to the optic thalamus, A2, and in part to the pons, and thus to the cerebellar hemisphere of the 
opposite side; B, motor tract from the central convolutions to the facial nucleus in the pons and to the spinal 
cord; C, sensory tract from posterior columns of the cord, through the posterior part of the medulla, pons, crus, 
and capsule to the parietal lobe; D, visual tract from the optic thalamus (OT) to the occipital lobe; E, auditory 
tract from the int. geniculate body (to which a tract passes from the VIII. N. nucleus) to the temporal lobe; 
E, superior cerebellar peduncle; G, middle cerebellar peduncle; II, inferior cerebellar peduncle; CN, caudate 
nucleus; CQ, corpora quadrigemina. The numerals refer to the cranial nerves. (Starr.) 
3. The Association Fibres (Figs. 591 and 592) connect different structures in the 
same hemispheres, and are in or near to the cortex. They take origin from the 
small pyramidal and polymorphous cells of the deep layer of the cortex. Their 
direction is parallel to the surface of the hemisphere, and in their course they 
cross the projection and commissural fibres. They are of two kinds: (1) those 
which unite adjacent convolutions, short association fibres; (2) those which pass 
between more distant parts in the same hemisphere, long association fibres. 
The short association fibres are situated immediately beneath the gray substance 
of the cortex of the hemispheres, and connect together adjacent convolutions. 
They constitute subcortical tracts and are divided into arcuate fibres and tangen- 
tial fibres. Some of these fibres connect the "visual sensory area with the visual 
memory area, and the auditory sensory with the auditory memory atea."2 
The long association fibres associate cerebral centres which are far apart. They 
are gathered into bundles and dip down deep into the centrum ovale. They 
1 Anatomy of the Brain and Spinal Cord, by Harris E. Santee 2 Ibid. THE MID BRAIN 
917 
include the following: (a) the uncinate fasciculus; (6) the cingulum; (c) the superior 
longitudinal fasciculus; (d) the inferior longitudinal fasciculus; (e) the perpendicular 
fasciculus; (/) the fornix; (g) the occipito-frontal fasciculus. 
(a) The Uncinate Fasciculus (fasciculus uncinatus) (Fig. 592).-The unci- 
nate fasciculus passes across the bottom of the Sylvian fissure and connects the 
Fig. 591.-Diagram showing association-fibres of the hemisphere. (Testut.) 
Fig. 592.-The long association fibres. A shows the bundles contained in the lateral white substance of the 
hemispheres; B, those in the mesial white matter. At the upper border a few short association bundles are 
shown diagrammatically. (Jakob.) 
uncinate convolution with the orbital portion of the frontal lobe. Barker points 
out that this fasciculus joins the third frontal, internal orbital, and posterior 
orbital convolutions with the limbic lobe. THE NERVOUS SYSTEM 
918 
(6) The Cingulum or the Fillet of the Gyrus Fornicatus (Fig. 592) is 
a band of white matter which encircles the hemisphere in an antero-posterior 
direction, lying in the substance of the convolution of the corpus callosum. 
Commencing in front at the anterior perforated space, it passes forward and 
upward parallel with the rostrum, wind around the genu, runs in the convolu- 
tion from before backward, immediately above the corpus callosum, turns around 
its posterior extremity, and passes into the Hippocampus major, through which 
it courses to its anterior extremity. According to Beem there are three sets of 
fibres in the cingulum. The anterior fibres join the internal olfactory root and 
the anterior perforated lamina with the front of the frontal lobe. The horizontal 
fibres join the gyrus fornicatus with the frontal lobe. The posterior fibres join 
the fusiform convolution (the fourth temporal) with the hippocampal convolution 
and the temporal lobe.1 
(c) The Superior Longitudinal Fasciculus {fasciculus longitudinalis supe- 
rior) (Fig. 592).-The superior longitudinal fasciculus is beneath the convex 
surface of the hemisphere. It joins the frontal cortex with the parietal and tem- 
poral cortex and brings into relation the motor speech centres and the centres of 
auditory and visual memories. 
(d) The Inferior Longitudinal Fasciculus (fasciculus longitudinalis infe- 
rior) (Fig. 592).-The inferior longitudinal fasciculus associates the centres of 
auditory and visual memory. It is a collection of fibres which connects the 
temporal and occipital lobes, running along the outer wall of the descending 
and posterior cornua of the lateral ventricle. 
(e) The Perpendicular Fasciculus or Fasciculus Rectus (Fig. 592).- 
The perpendicular fasciculus runs vertically in front of the occipital lobe, and 
connects the inferior parietal lobule with the second and third temporal convolu- 
tions, and also connects the superior occipital convolution with the inferior occipital 
and the fourth temporal convolutions. 
(/) The Fornix (corpus forn icis) (Fig. 586).-The fornix by its anterior pillar is 
connected with the corpus albicans and by means of the bundle of A icq d'Azyr 
with the optic thalamus. Most of the posterior pillar ends in the hippocampus 
major, but some of the fibres (the corpus fimbriatum) go to the uncinate con- 
volution. Through the fibres of the lyra it probably also unites the opposite 
hippocampal convolutions. 
(g) The Occipito-frontal Fasciculus of Forel (fasciculus occipitofron- 
talis) (Fig. 592).-The occipito-frontal fasciculus is placed between the cingulum 
and the superior longitudinal fasciculus. It connects the frontal cortex with the 
occipital cortex. Some regard it as a part of the corpus callosum. 
The Gray Matter of the Cerebrum.-The gray matter of the cerebrum, in 
accordance with its situation, is disposed in three great groups: (1) The gray 
matter of the cerebral cortex or cortical gray matter. (2) The gray matter of the 
ganglia or ganglionar gray matter. (3) The central or ventricular gray matter. 
The Gray Matter of the Cortex.-The cortex, bark or envelope of the cerebrum, 
is a thin layer of gray matter on the surface, which encompasses the white matter 
of the hemispheres (centrum ovale). The cortex has been mapped out into definite 
areas and centres, each of which is connected with a well-defined function 
(p. 952). 
On examining a section through one of the convolutions of the Rolandic area 
with a lens, it is seen to consist of alternating white and gray layers thus disposed 
from the surface inward: (1) a thin layer of white substance; (2) a layer of gray 
substance; (3) a second layer of white substance (outer band of Baillarger or 
band of Gennari); (4) a second gray layer; (5) a third white layer (inner band of 
' Anatomy of the Brain and Nervous System. By Harris E. Santee. THE MID-BRAIN 
919 
Baillarger); (6) a third gray layer, which rests on the medullary substance of the 
convolution. 
The cortex is made up of nerve-cells which vary in size and shape, and of nerve- 
fibres, some of which are medullated, but most of which are non-medullated, 
embedded in a matrix of neuroglia. 
The nerve-cells in a typical section of the cortex are arranged in five layers (Fig. 
593). named from the surface inward as follows: (1) the molecular layer; (2) the layer 
of small pyramidal cells; (3) the layer of large pyramidal cells; (4) the layer of poly- 
morphous cells; (5) the layer of fusiform cell-bodies (Santee) (not shown in Fig. 593). 
The Molecular, the Superficial or the Neuroglia Layer.-This layer 
is immediately adjacent to the pia mater. Neuroglia constitutes the greatest 
amount of the superficial layer; 
hence its other name of neuroglia 
layer. In this layer the cells are 
irregular and are known as the neu- 
rones of Cajal. The cells are polyg- 
onal, triangular, and fusiform in 
shape, and are associative in func- 
tion. Each polygonal cell gives off 
some four or five dendrites, while 
its axones may arise directly from 
the cell or from one of its dendrites. 
The axones and dendrites of these 
cells ramify in the molecular layer. 
Each triangular cell gives off two or 
three dendrites, from one of which 
the axone arises, the dendrites and 
the axone ramifying in the molec- 
ular layer, The fusiform cells are 
placed with their long axes parallel 
to the surface and are mostly bipolar, 
each pole being prolonged into a 
dendrite, which runs horizontally for 
some distance and furnishes ascend- 
ing branches. Their axones, two or 
three in number, arise from the den- 
drites, and, like them, take a hori- 
zontal course, giving off numerous 
ascending collaterals. The distri- 
bution of the axones and dendrites 
of all three sets of cells is limited to 
the molecular layer. 
Besides the neuroglia, the cells, 
and the gray fibres, this layer contains medullated nerve-fibres arranged in a 
network and constituting the superficial white layer. 
The Layer of Small and the Layer of Large Pyramidal Cells.-The 
cells in the second and third layers may be studied together, since, with the excep- 
tion of the difference in size and the more superficial position of the smaller cells, 
they resemble each other. The body of each cell is pyramidal in shape, its base 
being directed to the deeper parts and its apex toward the surface. It contains 
granular pigment, and stains deeply with ordinary reagents. The nucleus is 
nucleolated, of large size, and round or oval in shape. The base of the cell gives 
off the axone, and this passes into the central white substance, giving off collaterals 
in its course, and is distributed as a projection, commissural, or association fibre. 
Molecular layer. 
Layer of small 
pyramidal cells. 
Layer of large 
pyramidal cells. 
Polymorphous 
layer. 
White medullary 
substance. 
Fig. 593.-The four layers of cells in the cerebral cortex. 
Modified from Testut. (After Cajal.) 920 
THE NERVOUS SYSTEM 
Both the apical and basal parts of the cell give off dendrites. The apical dendrite 
is directed toward the surface, and ends in the molecular layer by dividing into 
numerous branches, all of which may be seen, when prepared by the silver or 
methylene-blue method, to be studded with projecting bristle-like processes. The 
larger pyramidal cells, especially in the Rolandic area, may exceed 50/2 in length 
and 40/2 in breadth, and are termed giant cells. The chief function of the small 
pyramids is commissural and associative. The chief function of the large pyramids 
is motor, but they have also commissural and associative functions. 
Layer of Polymorphous Cells.-The cells in this layer, as their name implies, 
are very irregular in contour, the commonest varieties being of a spindle, star, 
oval, or triangular shape. Their dendrites are directed outward, toward, but do 
not reach, the molecular layer; their axones pass into the subjacent white matter. 
From this layer come commissural fibres, long association fibres, and some pro- 
jection fibres. 
There are two other kinds of cells in the cerebral cortex, but their axones pass 
in a direction opposite to that of the pyramidal and polymorphous cells, among 
which they lie. They are: (a) the cells of Golgi, the axones of which do not 
become medullated, but divide immediately after their origin into a large number 
of branches, which are directed toward the surface of the cortex; (b) the cells of 
Martinotti, which are chiefly found in the polymorphous layer. Their dendrites 
are short, and may have an ascending or descending course, while their axones 
pass out into the molecular layer and form an extensive horizontal arborization. 
Layer of Fusiform Cell-bodies.-It receives the name of the claustral 
formation, because it is formed like the claustrum. This layer is not sharply 
defined from the white matter beneath; the change from one to the other is gradual. 
The long axes of most of the cells are perpendicular to the surface of the hemi- 
sphere, but beneath the fissures they are parallel to the surface (Santee). "The 
commissural and long association fibres belong, for the most part, to the fusi- 
form and polymorphous neurones.''1 
Nerve-fibres.-These fill up a large part of the intervals between the cells. Some 
of these fibres form fascicului; some are isolated, and others are arranged in 
plexuses. They may be medullated or non-medullated-the latter comprising 
the axones of the smallest pyramidal cells and the cells of Golgi. In their direction 
the fibres may be either transverse, the transverse tangential or horizontal fibres, 
or vertical, the vertical or radial fibres. The transverse fibres run parallel to the 
surface of the hemisphere, intersecting the vertical fibres at a right angle. They 
consist of several strata, of which the following are the most important: (1) a 
stratum of white fibres covering the superficial aspect of the molecular layer; (2) 
the band of Bechterew, found in certain parts of the superficial portion of the 
layer of the smaller pyramidal cells; (3) the external or outer band of Baillarger 
or th? band of Gennari, which runs through the layer of large pyramidal cells; 
(4) the internal band of Baillarger, which intervenes between the layer of large 
pyramidal cells and the polymorphous layer. According to Cajal, the transverse 
fibres consist of (a) the collaterals of the pyramidal and polymorphous cells and 
of the cells of Martinotti; (b) the arborizations of the axones of Golgi's cells; 
(c) the collaterals and terminal arborizations of the projection, commissural, 
or association fibres. The vertical fibres.-Some of these-viz., the axones of the 
pyramidal and polymorphous cells-are directed toward the central white matter, 
while others, the terminations of the commissural, projection, or association fibres, 
pass outward to end in the cortex. The axones of the cells of Martinotti are also 
ascending fibres. 
In certain parts of the cortex this typical structure is departed from. The chief 
' Anatomy of the Brain and Spinal Cord. By Harris E. Santee. THE MID-BRAIN 
921 
of these regions are: (1) the occipital lobe, (2) the hippocampus major, (3) the 
dentate convolution, and (4) the olfactory bulb. 
Special Types of Gray Matter. 1. The Occipital Lobe.-In the cuneus and 
the calcarine fissure of the occipital lobe, Cajal has recently described as many as 
nine layers. Here the inner band of Baillarger is absent; the outer band of Bail- 
larger or band of Gennari is, on the other hand, of considerable thickness. If a 
section be examined microscopically, an additional layer is seen to be interpolated 
between the molecular layer and the layer of small pyramidal cells. This extra 
layer consists of two or three strata of fusiform cells, the long axes of which are at 
right angles to the surface. Each cell gives off two dendrites, external and internal, 
from the latter of which the axone arises and passes into the white central sub- 
stance. In the layer of small pyramidal cells, fusiform cells, identical with the 
above, are seen, as well as ovoid or star-like cells with ascending axones, the cells 
of Martinotti. This area of the cortex forms the visual centre, and it has been 
shown by Dr. J. S. Bolton1 that in old-standing cases of optic atrophy the thick- 
ness of Gennari's band is reduced by nearly 50 per cent. 
2. The Hippocampus Major.-In the hippocampus major the molecular layer is 
very thick and contains a large number of Golgi cells. It has been divided into 
three strata: (a) S. convolutum or S. granulosum, containing many tangential 
fibres; (b) S. lacunosum, presenting numerous lymphatic or vascular spaces; (c) 
S. radiatum, exhibiting a rich plexus of fibrils. The two layers of pyramidal cells 
are condensed into one, and the cells are mostly of large size. The axones of the 
cells in the polymorphous layer may run in an ascending, descending, or horizontal 
direction. Between the polymorphous layer and the ventricular ependyma is the 
white substance of the alveus. 
3. The Dentate Convolution.-In the rudimentary dentate convolution the molec- 
ular layer contains some pyramidal cells, while the layer of pyramidal cells is 
almost entirely represented by small ovoid cells. 
4. The Olfactory Bulb.-In many of the lower animals this contains a cavity 
which communicates through the hollow olfactory stalk with the cavity of the 
lateral ventricle. In man the original cavity is filled up by neuroglia and its 
wall becomes thickened, but much more so on its ventral than on its dorsal aspect. 
Its dorsal part contains a small amount of gray and white matter, but it is scanty 
and ill defined. A section through the ventral part shows it to consist of the 
following layers from without inward. (1) A layer of olfactory nerve-fibres, which 
are the non-medullated axones prolonged from the olfactory cells of the nose, and 
which reach the bulb by passing through the cribriform plate of the ethmoid bone. 
At first they cover the bulb, and then penetrate it to end by forming synapses 
with the dendrites of the mitral cells, presently to be described. (2) Glomerular 
layer (stratum glomerulosum).-This contains numerous spheroidal reticulated 
enlargements, termed glomeruli, which are produced by the branching and arbor- 
ization of the processes of the olfactory nerve-fibres with the descending dendrites 
of the mitral cells. (3) Molecular layer.-This layer is formed of a matrix of 
neuroglia, embedded in which are the mitral cells. 'These cells are pyramidal in 
shape, and the basal part of each gives off a thick dendrite which descends into 
the glomerular layer, where it arborizes as indicated above, and others which 
interlace with similar dendrites of neighboring mitral cells. The axones pass 
through the next layer into the white matter of the bulb, from which, after becom- 
ing bent on themselves at a right angle, they are continued into the olfactory tract. 
(4) N erve-fibre layer.-This lies next the central core of neuroglia, and its fibres 
consist of the axones or afferent processes of the mitral cells which are passing to 
the brain; some efferent fibres are, however, also present, and terminate in the 
1 Phil. Trans, of Royal Society, Series B, vol. cxciii. p. 165. THE NERVOUS SYSTEM 
922 
molecular layer, but nothing is known as to their exact origin. It is to be remem- 
bered that the olfactory path is uncrossed or almost completely uncrossed. 
The Gray Matter of the Ganglia or the Ganglionar Gray Matter.-These ganglia 
have been previously described. They are as follows: The corpus striatum, the 
optic thalamus, the external geniculate body, the internal geniculate body, the 
nucleus of Luys, the red nucleus of the tegmentum, the anterior quadrigeminal 
body, the posterior quadrigeminal body, the substantia nigra, and the inter- 
peduncular ganglion. 
The Central or Ventricular Gray Matter.-This includes the lamina cinerea, the 
tuber cinereum, the middle commissure, the nuclei of the third and fourth 
cranial nerves, and the gray matter about the aqueduct of Sylvius. 
IV. The Hind-brain (Rhombencephalon). 
From the hind-brain or rhombencephalon, as previously stated, come two vesi- 
cles, the metencephalon, or upper portion of the hind-brain or the hind-brain proper, 
and the myelencephalon, or lower portion of the hind-brain. From the metence- 
phalon come the pons and the cerebellum. From the myelencephalon comes the 
medulla oblongata. The original hind-brain remains in the brain of the adult 
as the fourth ventricle. 
Pons Varolii (Figs. 557, 599, and 693).-The pons Varolii is the bond of union 
between the various segments of the encephalon, connecting the cerebrum above, 
the medulla oblongata below, and the cerebellum behind. It lies upon a portion 
of the clivus, the groove of bone between the foramen magnum and the dorsum 
sellae, and is situated above the medulla oblongata, below the crura cerebri, and 
between the hemispheres of the cerebellum. It is about an inch in length, an 
inch in thickness, and an inch and a half in width. It presents four surfaces: the 
superior surface, which is attached, by direct continuation of fibres, to the mid- 
brain; the inferior surface, which is continuous with the medulla oblongata; the 
anterior or ventral and the posterior or dorsal surfaces are free. 
The Anterior or Ventral Surface, the Tuber Annulare or Base (pars basilaris pontis), 
is very prominent, markedly convex from side to side, but less so from before back- 
ward. It consists of transverse white fibres (Fig. 594), which arch like a bridge 
across the middle line, andon either side are gathered together into a compact mass, 
forming the middle peduncle of the cerebellum (Fig. 599). Above and below it 
presents a well-defined border; below, its transverse fibres slightly overlap the 
pyramidal bodies of the medulla, which disappear into its substance; above, the 
transverse fibres slightly overlap the crura cerebri which emerge from it. This 
surface rests upon the clivus of the sphenoid bone, and presents in the middle 
line a longitudinal groove (sulcus basilaris) (Fig. 603), wider in front than behind, 
in which rests the basilar artery. Slightly in advance of the middle of the ventral 
surface of the pons and at the margin the two roots of the fifth nerve emerge. 
The Posterior or Dorsal Surface (pars dorsalis pontis).-The posterior or dorsal 
surface of the pons is free, but is concealed from view by the cerebellum. It forms 
the upper part of the floor of the fourth ventricle, and will be described with this 
cavity (Fig. 604 and p. 942). 
Structure.-Transverse sections of the pons Varolii show that it consists of two 
parts, which differ in appearance and structure from each other: the anterior or 
ventral portion (Fig. 594) consists for the most part of fibres arranged in transverse 
and longitudinal bundles with a small amount of gray matter; the posterior or dorsal 
portion is chiefly constituted by a continuation upward of the reticular formation 
of the gray matter of the medulla, and is called the tegmental portion, as most 
of its constituents are continued into the tegmentum of the crus cerebri. It is 
subdivided into lateral halves by a median raphe continuous with that of the THE IIIND-BRAIN 
923 
medulla, but the raphe does not extend into the ventral half of the pons, being 
here obliterated by the transverse fibres. 
Transverse Fibres of the Pons.-The transverse fibres are placed in the ventral 
portion of the pons. These are disposed in three sets: 
1. The Superficial or Ventral Transverse Fibres (fibrae pontis supcrficiales) (Fig. 
594) constitute a rather thin layer on the ventral surface of the pons. This thin 
white layer is called the tuber annulare. 
2. The Middle or Deep Transverse Fibres are placed dorsally or above the 
superficial transverse fibres, and form a thick layer, with much gray matter 
between them. These collections of gray matter are named the nuclei pontis. In 
this layer of transverse fibres are longitudinal fibres coming from the middle 
three-fifths of the crustae and passing to the pyramids of the medulla and also 
Superficial 
and middle 
fibres of pons 
reflected. 
Fig. 594 -Superficial dissection of the medulla oblongata and pons. (Ellis.) 
fibres of the fronto-pontal, intermediate, and temporo-frontal tracts (Santee). 
The middle cerebellar peduncles (brachia pontis) (Fig- 599) are formed by the 
superficial and middle transverse fibres. 
3. The Dorsal Transverse or Dorsal Deep Transverse Fibres lie dorsally to the 
middle transverse fibres and the pyramidal fibres between them and the fonnatio 
reticularis. These fibres are collected into a distinct bundle which is most defi- 
nite in the posterior portion of the pons and in which region it is named the trape- 
zium (corpus trapezoidewn), because of its shape. The trapezium is the mark of 
the boundary between the dorsal and ventral surfaces. The chief origin of the 
trapezium is from the cochlear nerve nuclei; they decussate and pass by the 
lateral fillet to the inferior quadrigeminal body. Santee points out that the trape- 
zium and lateral fillet are part of the auditory conduction path. 
Longitudinal Fibres of the Pons.-These are found in both the ventral and dorsal 
portions. There are three sets: 924 
THE NERVOUS SYSTEM 
The Ventral Longitudinal or Ventral Deep Longitudinal Fibres (Fig. 594) are chiefly 
the continuation of the pyramidal fibres of the crustae which reach the pyramids 
of the medulla. They form a thick bundle. Among these fibres are some from 
the opposite cerebellar peduncles and the nuclei pontis. During the descent of 
the pyramidal tract it grows constantly smaller, because it loses here and there 
fibres which pass to motor cranial-nerve nuclei. The pressure of the thick bundle 
of pyramidal fibres causes a bulging of the superficial transverse fibres on the 
ventral surface of the pons and the formation of the mesial groove between them. 
The Middle Longitudinal or Dorsal Deep Longitudinal Fibres are placed in the 
floor of the fourth ventricle in the pontine formatio reticularis, which is continuous 
with the formatio reticularis of the medulla oblongata. The pontine formatio 
reticularis is a network of these longitudinal fibres with some oblique fibres, the 
network containing gray matter. Some of the gray matter of the formatio retic- 
ularis forms the nuclei of certain cranial nerves; the rest of it forms the nuclei 
of the formatio reticularis. Santee describes six bundles of longitudinal fibres in 
the formatio reticularis: l.The fillet (lemniscus), consisting of the lateral, the median, 
and the superior fillet (lemniscus lateralis, lemniscus medialis, lemniscus superior), 
passing to and through the tegmentum to the thalamus and the two quadri- 
geminal bodies. 2. The posterior longitudinal bundle (fasciculus longitudinalis 
medialis) contains both ascending and descending fibres; most of the fibres do 
not decussate but reach the anterior column of the same side of the cord. 
Some of its fibres decussate through the pons, medulla, and mid-brain. 
According to Santee, it receives ascending fibres from the gray matter of the 
anterior cornu of the spinal cord, from the sensory nuclei of cranial nerves, and 
through the middle peduncle from the cerebellum. It terminates in the sub- 
thalamic region. The fibres decussate across the posterior commissure. In this 
bundle are motor fibres passing from the sixth to the third nerves and from the 
third to the seventh. 3. The anterior longitudinal bundle (fasciculus ventralis) 
passes from the superior quadrigeminal body to the gray matter of the anterior 
cornu of the cervical cord. "It is the pupillo-dilator tract."1 4. The olivary 
bundle or the central tegmental tract (fascicidus tegmenti centralis) arises from 
the inferior olivary nucleus of the medulla, ascends to the lenticular nucleus, 
from which situation some of the fibres pass to the cortex. 5. The crossed descend- 
ing tract from the red nucleus. It arises in the red nucleus of the tegmentum, 
soon crosses the raphe, and, as Barker points out, reaches the lumbar region of 
the cord. In the pons the fibres are in the lateral fillet. 6. The ascending or infe- 
rior sensory root of the fifth nerve (tractus spinalis nervi trigemini) arises near the 
Rolandic tubercle in the medulla and effects a junction with the superior root 
ventrally to the superior peduncles of the cerebellum. 
The Dorsal Longitudinal or Superficial Longitudinal Fibres constitute the roof 
of the superior portion of the fourth ventricle, and form the superior peduncles 
of the cerebellum (p. 932) and the valve of Vieussens (p. 933). 
Gray Matter of the Pons.-The nuclei pontis constitute a portion of it, the gray 
matter of the formatio recticularis the balance. 
The Nuclei Pontis, which have been previously referred to, are collections of 
gray matter on each side of the pons, between the fibres of the middle transverse 
bundle and of the ventral longitudinal bundle of the pons. The nucleus pontis 
of each side receives fibres from the crusta-viz., the intermediate bundle, the frontal 
cerebro-cortico-pontal tract (p. 893), and the temporal cerebro-cortico-pontal tract 
(p. 894), and also receives fibres from the middle peduncle of the cerebellum 
(p. 934). It sends fibres by the middle peduncle to the opposite cerebellar hemi- 
sphere. The nuclei pontis contain numerous multipolar ganglion cells. 
' Anatomy of the Brain and Spinal Cord. By Harris E. Santee. THE HIND-BRAIN 
925 
The Gray Matter of the Pontine or Formatio Reticularis forms the superior 
olivary nucleus, the nuclei of the trapezium, numerous nuclei of the formatio reticu- 
laris, and nuclei of certain cranial nerves. The portion of the formatio reticularis 
between the roots of the sixth pair of cranial nerves is called the formatio reticularis 
alba; the portion between the roots of the sixth and seventh nerves is called the 
formatio reticularis grisea. 
The Superior Olivary Nucleus (nucleus olivaris superior) is upon the dorsal surface 
of the outer part of that collection of fibres known as the trapezium. It is not large 
enough to be visible to the naked eye and contains very small nerve-cells. It is a 
part of the auditory pathway, and its fibres enter the accessory auditorv nucleus 
of the opposite side. The nuclei of the trapezium are in the auditory pathway. 
There are numerous other nuclei in the formatio reticularis (nuclei of the formatio 
reticularis, or the nucleus magnocellularis diffusus of Koelliker). The cells of 
these nuclei are large and multipolar, and their axones cross to the opposite side 
of the pons. They receive fibres from cranial-nerve nuclei and axones from the 
cells of the folium of the cerebellum which are called cells of Purkinje. These 
nuclei are probably connected with various pontine tracts. 
The Nuclei of the Fifth Nerve (Fig. 613) in the pons are two in number, one for 
the motor root and the other for the sensory. The motor nucleus is situated in the 
higher portion of the pons, close under the dorsal surface and along the line of the 
lateral margin of the fourth ventricle. The sensory nucleus lies external to the motor 
one, beneath the superior peduncle of the cerebellum, which forms the lateral 
boundary of the upper half of the fourth ventricle. Some of the fibres from these 
nuclei pass to the raphd of the pons, and thence probably to the higher parts of the 
brain; the rest form the nerve-roots of the motor and sensory parts of the fifth 
nerve respectively. They pass through the pons to emerge on its ventral surface 
at its lateral and constricted portion, nearer its superior than its inferior margin. 
It must be mentioned that the whole of the roots of the fifth nerve are not formed 
from these nuclei. The sensory root is partly formed by a long tract of fibres, 
known as the ascending root, which can be traced through the pons to the nucleus 
of Rolando in the medulla. The motor root, in like manner, is partly formed by 
a long tract of fibres, which passes downward from the gray matter in the floor 
of the fourth ventricle and the floor of the Sylvian aqueduct and which is termed 
the descending root. 
The Nucleus of the Sixth Nerve (Fig. 613) is situated beneath the floor of the fourth 
ventricle, on either side of the middle line. It lies close to the root of the facial nerve, 
immediately to be described, being a little external to and beneath it, and corre- 
sponds to the upper half of the fasciculus teres of the floor of the fourth ventricle 
(Fig. 606). The fibres pass through the substance of the pons, and emerge at the 
lower margin of this structure, between it and the upper end of the medulla. 
The Nucleus of the Facial Nerve (nucleus n. facialis) (Fig.613) is of elongated form, 
and is situated deeply in the reticular formation below the superior fovea of the floor 
of the fourth ventricle. The roots of the nerve derived from it pursue a remarkably 
tortuous course in the substance of the pons. At first they pass backward and 
inward till they reach the floor of the fourth ventricle, close to the median groove, 
where they are collected into a rounded bundle. This passes upward and for- 
ward, producing an elevation (fasciculus teres) in the floor of the ventricle, and 
then takes a sharp bend and arches outward through the substance of the pons 
to emerge at its lower border in the interval between the olivary and restiform 
bodies of the medulla. The pars intermedia of Wrisberg takes origin from the 
floor of the fourth ventricle beneath the inferior fovea. 
The Nuclei of the Auditory Nerve (nuclei n. acustici) (Fig. 613) are two in number, 
dorsal and ventral. The origin of the dorsal or vestibular root is from a nucleus situ- 
ated in the medulla, but prolonged upward into the pons, where it lies beneath the THE NERVOUS SYSTEM 
926 
upper half of the floor of the fourth ventricle {nuclei n. vestibularis). The dorsal 
root also takes origin from the cerebellum (from the nucleus fastigii and the 
nucleus globosus). According to Golgi, the vestibular root is also in connection 
with the nucleus of Deiters and the nucleus of Bechterew. The ventral or 
cochlear root arises from the ventral or accessory nucleus (nuclei n. cochlearis) 
which is also partly contained in the medulla and partly in the pons. In the 
medulla it is situated on the antero-external surface of the restiform body, 
lying between the vestibular and cochlear divisions of the auditory nerve, the 
latter being to its outer side. In the pons it is seen to lie beyond the boundary of 
the fourth ventricle on the outer and ventral aspect of the restiform body. A third 
nucleus, nucleus of Deiters, is sometimes termed the outer nucleus of the auditory 
nerve. It is situated below the outer angle of the fourth ventricle, and contains 
multipolar nerve-cells of large size. The outer portion of the nucleus of Deiters 
is called Bechterew's nucleus. The root of the auditory nerve consists of two 
portions, lateral and mesial, which pass, one to the outer and the other to the 
inner side of the restiform body, those from the lateral part arising mainly from 
the ventral nucleus, those from the mesial part arising from the dorsal auditory 
nucleus. They emerge at the lower border of the pons, in the groove between 
the olivary and restiform bodies. 
The Cerebellum or Little Brain (Figs. 557, 595, 596, 597, 598, and 599).- 
"Die cerebellum is contained in the inferior occipital fossae, and is situated beneath 
the occipital lobes of the cerebrum, from which it is separated by the tentorium 
cerebelli. In form it is oblong and flattened from above downward, its great 
diameter being from side to side. It measures from three and a half to four inches 
transversely, two to two and a half inches from before backward, and is about 
two inches thick in the centre, and about six lines thick at the circumference. 
It consists of gray and white matter: the former, darker than that of the cere- 
brum, occupies the surface (substantia corticalis), and masses of it are also 
found in the interior. The white matter is in the interior (corpus medullare). 
The surface of the cerebellum is not convoluted like that of the cerebrum, but 
is traversed by numerous curved furrows or sulci, which vary in depth at dif- 
ferent parts, and separate the laminae of which it is composed. 
Lobes of the Cerebellum.-The cerebellum consists of three parts or lobes, a 
median and two lateral. They are all continuous with each other, and are sub- 
stantially the same in structure. The median portion is called the worm or vermi- 
form process (vermis), from the annulated appearance which it presents, owing to 
transverse ridges and furrows upon it. On the upper surface of the cerebellum, 
the worm is only slightly elevated above the level of the lateral portions, but on the 
under surface it is sunk almost out of sight in a deep depression, which is called 
the valley or vallecula (vallecula cerebelli). The lateral parts of the cerebellum are 
called hemispheres (hemisphaeria cerebelli); they attain a considerable size, overlap- 
ping and obscuring the inferior part of the worm. Below and behind they are 
separated by a deep notch, the posterior cerebellar notch or the incisura marsupialis 
(incisura cerebelli posterior), and in front by a broader, shallower notch, the anterior 
cerebellar notch or the incisura semilunaris (incisura cerebelli anterior). The anterior 
notch lies close to the pons and upper part of the medulla, and its upper edge encir- 
cles the posterior corpora quadrigemina. The posterior notch is free, and contains, 
in the recent state, the upper part of the falx cerebelli. The sides of the notches are 
formed by the margins of the hemispheres, while the bottom of the notches is 
formed by the anterior and posterior extremities of the worm respectively. The 
cerebellum is characterized by its laminated or foliated appearance; it is everywhere 
marked by deep, transverse, somewhat curved fissures, which lie close together, 
and extend fora considerable depth into the substance of the cerebellum, dividing 
it into a series of layers or leaves. Upon making sections across the laminae THE HIND-BRAIN 
927 
it will be seen that the folia, though differing in appearance from the convolu- 
tions of the cerebrum, are homologous with them, inasmuch as they consist of a 
central white substance, with a covering or cortex of gray matter. 
The largest and deepest fissure is the great horizontal fissure (sulcus horizontalis 
cerebelli) (Figs. 595 and 596). It commences in front at the pons, and passes hori- 
zontally around the free margin of the hemisphere to the middle line behind, and 
divides the cerebellum into an upper and lower portion. Several secondary but 
deep fissures separate the cerebellum into lobes, and these are further subdivided by 
shallower sulci, which separate the individual folia or laminae from each other. 
When the cerebellum is removed from the pons and medulla, the transverse 
fissure (fissura transversa cerebelli) is seen upon its anterior margin. This fissure 
is between the superior and inferior medullary laminae. 
The white matter in the interior of the cerebellum is known as the medullary 
body (corpus medullareY About the middle it divides into a superior and an inferior 
lamina (laminae medullares). These laminae help to form the fourth ventricle. 
The superior lamina is composed of the superior medullary velum and the 
peduncles of the cerebellum. The inferior lamina constitutes the inferior 
medullary velum. 
The cerebellum is connected to the cerebrum, pons, and medulla by three pairs 
of peduncles, which will be described in the sequel; a superior pair connect it 
with the cerebrum; a middle pair, with the pons; and an inferior pair, with the 
medulla. 
Ala lobuli centralis. 
Post-central 
fissure. 
Pre-clival fissure. 
Great 
horizontal 
fissure. 
Lobulus centralis. 
Post-clival fissure. 
Clivus 
monticuli. 
Fig 59.5.-Upper surface of the cerebellum. (Schiifer.) 
The Upper Surface of the Cerebellum (facies cerebelli superior) (Fig. 595).-The 
superior surface of the cerebellum is somewhat elevated in the middle line and 
sloped toward its circumference, its hemispheres being connected together by an 
elevated median portion or lobe, the superior vermis or superior vermiform process 
(vermis superior cerebelli). The front of the superior vermis is elevated, and the 
highest point is called the monticulus cerebelli. The surface is traversed by four 
curved fissures, which are named from their situation, in front or behind two 
prominent lobes of the worm, the central lobe and the clivus: (1) the pre-central 
fissure (sulcus praecentralis cerebelli); (2) the post-central fissure (sulcus postcentralis); 
(3) the pre-clival fissure, and (4) the post-clival fissure. These four fissures divide 
the entire upper surface of the cerebellum into five lobes, but the portion of the 
lobe in the worm has received a different name from that in the hemisphere, 
though the two are continuous with each other. The five lobes in the worm are 
named from before backward: (1) the lingula, (2) the central lobule, (3) the culmen 
monticuli, (4) the clivus monticuli, and (5) the folium cacuminis (folium vermis). 928 
THE NERVOUS SYSTEM 
The five lobes in the hemispheres are named from before backward: (1) the 
fraenulum, (2) the ala lobuli centralis, (3) anterior crescentic, (4) posterior crescentic, 
and (5) posterior superior. The arrangement of these fissures and lobules will be 
understood by reference to the accompanying schematic arrangement, in which 
the lobules are named in order from before backward with the fissures which 
separate them: 
Worm. 
Lingula. 
Hemisphere. 
Fraenulum. 
Pre-central Fissure. 
Lobulus centralis. Ala lobuli centralis. 
Post-central Fissure. 
Culmen monticuli. Anterior crescentic lobe. 
Pre-clival Fissure. 
Clivus monticuli. Posterior crescentic lobe. 
Post-clival Fissure. 
Folium cacuminis. Posterior superior lobe. 
'Phe Lingula (lingula cerebelli) (Fig. 598)is a tongue-shaped process of the vermis, 
which lies in the anterior cerebellar notch in front of the lobulus centralis, and is 
partially or completely concealed by it. It is in relation, in front, with the valve of 
Vieussens, on the dorsal surface of which it rests and with which it is connected; 
its white matter being continuous with that of the valve. At either side the 
lingula gradually shades off, and is prolonged only for a short distance into the 
hemispheres, where it forms the fraenulum (vinculum lingulae cerebelli). This does 
not stretch beyond the superior peduncle of the cerebellum over which it lies. 
The Central Lobe and Alae (lobulus centralis).-The lobusor lobulus centralis is 
a small square lobe, situated in the anterior notch. It overlaps the lingula and is 
in turn partially concealed by the culmen monticuli. Laterally the lobulus cen- 
tralis extends along the upper and anterior part of each hemisphere, where it 
forms a wing-like prolongation, the ala lobuli centralis. 
The Culmen Monticuli Cerebelli is much larger than the two lobes just described, 
and constitutes, with the succeeding lobe, the clivus, the bulk of the upper worm. 
In front it partially overlaps and obscures the lobulus centralis, and behind it is 
separated from the clivus by the pre-clival fissure. It forms the most prominent 
part of the upper worm, and is marked on its surface by three or four secondary 
fissures, dividing it up into smaller lobules. Laterally it is continuous with the 
anterior crescentic lobe of the hemisphere (pars anterior lobuli quadrangularis), 
which is distinctly differentiated from the posterior crescentic lobe by the pre- 
clival fissure, though the two were formerly classed together as the quadrate lobe 
of the lateral hemisphere. 
The Clivus Monticuli (decline monticuli cerebelli) is of considerable size, and, as 
stated above, forms with the culmen the major part of the superior worm. It con- 
sists of a group of laminae, which in front are separated from the culmen by the 
pre-clival fissure and behind appear to be almost continuous with the folium 
cacuminis, especially in the median line; but it will be found, on careful examina- 
tion, to be separated from it by a well-defined fissure, the post-clival fissure. Later- 
ally this lobe is continued into the hemispheres as the posterior crescentic lobe 
(pars posterior lobuli quadrangularis), w hich is somewhat semilunar in shape, and, 
with the anterior crescentic lobe, constitutes the greater part of the upper surface 
of the hemispheres. THE HIND BRAIN 
929 
The Folium Cacuminis (folium vermis) is a short and narrow, concealed band 
at the posterior extremity of the worm, consisting apparently of a single folium, 
but in reality marked on its upper and under surfaces by secondary fissures. 
Laterally it expands in either hemisphere into a considerable lobe, which is semi- 
lunar in shape, and is situated at the postero-superior part of the hemisphere and 
Lobulus 
centralis. 
■Sup. medullary 
velum. 
Ala lobuli 
centralis. 
Post-nodular fissure. 
Flocculus. 
Pre- 
pyramidal 
fissure. 
Great 
horizontal 
fissure. 
Post- 
pyramidal 
fissure. 
Tuber valvuhe. 
Fig. 596.-Under surface of the cerebellum. (Schafer.) 
is bounded below by the great horizontal fissure. It is named the posterior superior 
lobe (lobulus semilunaris superior), and occupies the posterior third of the upper 
surface of the hemisphere, forming its rounded postero-lateral border. 
The Under Surface of the Cerebellum (facies cerebelli inferior) (Figs. 596 and 597). 
-The undersurface of the cerebellum presents in the middle line the inferior vermis 
N 
U 
Am. 
Bivent. 
Py. 
Fig. 597.-Diagram showing fissures on under surface of the cerebellum. F. Flocculus. N. Nodule. U. Uvula. 
Py. Pyramid. Am. Amygdala. Bivent. Biventral lobe. 
or inferior vermiform process (vermis inferior cerebelli), buried in the vallecula, 
and separated from the hemispheres by lateral grooves. Here, as on the upper 
surface, there are deep fissures, dividing it into separate segments or lobes, but 
the arrangement is more complicated, and the relation of the segments of the 
worm to those of the hemisphere is less clearly marked. The fissures are three 930 
THE NERVOUS SYSTEM 
in number, but are not so regularly disposed as those on the upper surface (Fig. 
597). They are named, from their relation to the pyramid and nodule, two of 
the lobes on the under surface of the worm: (1) post-nodular, (2) pre-pyramidal, 
and (3) post-pyramidal fissures. The part of the worm in front of the post-nodular 
fissure is termed the nodule (nodulus vermis'), and the lobule in the hemisphere 
corresponding with this is the flocculus. The next lobe is situated between the 
post-nodular and pre-pyramidal fissures. In the vermiform process it is known 
as the uvula, and its lateral expansion in the hemisphere is named the amygdala 
or tonsil. The lobule of the worm between the pre- and post-pyramidal fissures 
is the pyramid, and its corresponding part in the hemisphere is the biventral or 
digastric lobe. Finally, behind the post-pyramidal fissure in the worm is a small 
lobe, the tuber valvulae or tuber posticum; this, in the hemispheres, expands into a 
large lobe, which occupies at least two-thirds of the inferior surface of the cere- 
bellum, and is subdivided into two by a secondary fissure, named the post-gracile 
fissure. The anterior of the two subdivisions is named the slender lobe; and the 
posterior, the' inferior semilunar or posterior inferior lobe. These fissures and lobes 
are here arranged, from before backward, in a schematic form: 
Worm. 
Nodule. 
Hemisphere. 
Flocculus. 
Post-nodular Fissure. 
Uvula. Amygdala. 
Pre-pyramidal Fissure. 
Pyramid. Biventral lobe. 
Post-pyramidal Fissure. 
Slender lobe. 
Post-gracile Fissure. 
Inferior semilunar lobe. 
Tuber valvulae 
The Fissures of the Under Surfaces of the Cerebellum.-The chief fissures of the 
under surface, as stated above, are three in number, and are not so regularly dis- 
posed as on the upper surface. 
(1) The Post-nodular Fissure in the worm courses transversely across it, separat- 
ing the nodule in front from the uvula behind. When it reaches the hemispheres 
it passes in front of the amygdala, and then crosses between the flocculus in front 
and the biventral lobe behind, and joins the anterior end of the great horizontal 
fissure. 
(2) The Pre-pyramidal Fissure crosses the worm between the uvula in front and 
the pyramid behind, then curves laterally behind the amygdala, and passes forward 
along the outer border of this lobe, between it and the biventral lobe, to join the 
post-nodular sulcus. 
(3) The Post-pyramidal Fissure passes across the worm behind the pyramid and 
in front of the tuber valvulae, and in the hemispheres courses behind the amygdala 
and biventral lobes, and then along the outer border of the biventral lobe to the 
post-nodular sulcus. It cuts off at least two-thirds of the inferior surface of the 
hemisphere. From it a secondary sulcus springs, and, coursing forward and 
outward, divides this surface into two parts and falls into the great horizontal 
fissure. This sulcus is termed the post-gracile fissure. 
The Lobes of the Inferior Surface of the Cerebellum.-The Nodule {nodvlus vermis) 
is a distinct prominence, forming the anterior extremity of the inferior worm. It 
projects into the roof of the fourth ventricle, and can only be distinctly seen after 
the cerebellum has been separated from the medulla and pons. On each side of THE HIND-BRAIN 
931 
the nodule is a thin layer of white substance, named the inferior medullary velum. 
It is semilunar in form, its convex border being continuous with the middle 
peduncle of the cerebellum; it extends on either side as far as the flocculus, 
which it connects with the nodule. 
The flocculus (flocculi secondarii) is a prominent, irregular lobule, situated 
just in front of the biventral lobe, between it and the middle peduncle of the 
cerebellum. It takes origin from a fold of gray matter in the inferior medullary 
velum, which is anterior to the tonsil. This fold is called the peduncle of the 
flocculus (pedunculus flocculi). Externally the gray fold enlarges and the enlarge- 
ment is the flocculus. It is subdivided into a few small laminae. 
The Uvula (uvula vermis) occupies a considerable portion of the inferior worm; 
it is separated on either side from the amygdala by a deep groove, the sulcus val- 
leculae, at the bottom of which it is connected to the amygdala by a commissure 
of gray matter, indented on its surface, and called the furrowed band. The uvula 
is marked on its surface by three or four transverse fissures. 
The Tonsil or Amygdala (tonsilla cerebelli) is a rounded mass in the lateral 
hemisphere. There are two tonsils, one in each lateral hemisphere. Each lies 
in a deep fossa between the uvula and the biventral lobe; this fossa is known by 
the name of the bird's nest (nidus avis). 
The Pyramid Lobe (pyramis vermis) is a conical projection, forming the largest 
prominence of the lower worm. It is separated from the hemispheres by the sulcus 
valleculae, across which it is connected to the biventral lobe by an indistinct band 
of gray matter, analogous to the furrowed band already described. 
The Biventral Lobe or Digastric Lobule (lobulus biventer) is triangular in shape, 
with the apex pointing inward and backward to become joined by the connecting 
band to the pyramid. The external border is separated from the slender lobe by 
the post-pyramidal fissure. The base is directed forward, and is on a line with the 
anterior border of the amygdala, and is separated from the flocculus by the post- 
nodular fissure. 
The Tuber Valvulae or Tuber Posticum (tuber vermis) is the posterior division of 
the inferior worm. It is of small size, and laterally spreads out into the large poste- 
rior inferior lobes of the hemispheres. These lobes, which, as stated above, com- 
prise at least two-thirds of the inferior surface of the hemisphere, are divided into 
two by the post-gracile fissure. The anterior lobe is named the slender lobe, and 
the posterior, the inferior semilunar lobe (lobulus semilunaris inferior). Both these 
lobes show a tendency to subdivision into two; that of the slender lobe is well 
marked, and its subdivisions are sometimes described as distinct lobes and named 
the anterior and posterior slender lobes, the fissure between them being termed the 
intra-gracile fissure. 
The Internal Structure of the Cerebellum.-The cerebellum consists of white and 
gray matter. 
The White Matter.-If a sagittal section (Fig. 598) is made through either 
hemisphere of the cerebellum, the interior will be found to consist of a central 
stem of white matter, the medullary body (corpus medullare), which contains in its 
interior a gray mass, the corpus dentatum (nucleus dentatus). It is a fold of gray 
matter thrown into corrugations and surrounding a centre of white matter. From 
the surface of this central stem a series of plates of medullary matter are de- 
tached, which, covered with gray matter, form the laminae. In consequence of 
the main branches from the central stem dividing and subdividing, the section 
presents a characteristic appearance, which is named the arborvitae cerebelli. If 
a vertical section is made in the median plane of the cerebellum it will be found 
that the central stem divides into two main branches, which, from their direction, 
may be named respectively the vertical and the horizontal branch. The vertical 
branch passes upward to the culmen, where it subdivides freely, some of its ramifi- 932 
THE NERVOUS SYSTEM 
cations passing forward and upward to the central lobe. The horizontal branch 
passes backward to the folium cacuminis, considerably diminished in size in 
consequence of having given off large secondary branches: one, from its upper 
surface, ascends to the clivus; the others descend, and enter the lobes in the 
inferior vermiform process, the tuber valvulae, the pyramid, the uvula, and the 
nodule. In the interior of the worm is white matter called the corpus trapezoides. 
It is not necessary to describe in detail the various divisions of the white matter, 
as they correspond to the lobes on the surface. 
Anterior 
crescentic lobe. 
Ala lobuli centralis. 
■ Lingula. 
Superior peduncles 
of cerebellum. 
Posterior 
superior lobe. 
Great 
horizontal 
fissure. 
Slender lobe. 
Amygdala. 
Nodule. 
Fourth ventricle. 
Fig. 598.-Sagittal section of the cerebellum, near the point of junction of the worm with the hemisphere. 
(Schafer.) 
The white matter of the cerebellum includes three systems of fibres: (1) 
projection or peduncular fibres, which are directly continuous with those of the 
peduncles of the cerebellum; (2) the fibres proper (fibrae propriae) of the cere- 
bellum itself. 
Projection or Peduncular Fibres.-The medullary body, as it emerges from the 
anterior cerebellar notch, is composed of projection fibres. These fibres are 
continuous with the branches of the medullary body and constitute the arbor 
vitae. The medullary body divides into a superior lamina and an inferior lamina, 
and it also forms a portion of the fourth ventricle. The inferior lamina is the 
inferior medullary velum, and its fibres reach the nodule and each flocculus. 
The superior lamina forms the superior medullary velum and the cerebellar 
peduncles. 
The Peduncles of the Cerebellum (Figs. 599 and 600).-From the anterior part 
of each hemisphere arise three large processes or peduncles-superior, middle, 
and inferior peduncles-by which the cerebellum is connected with the rest of 
the encephalon. 
The Superior Cerebellar Peduncles or Crura ad Cerebrum (brachia conjunctiva 
cerebelli) form the upper lateral boundaries of the floor of the fourth ventricle. 
As they extend forward and upward they converge on the dorsal aspect of the 
ventricle, and thus assist in roofing it in. They may be traced as far as the corpora 
quadrigemina, under which they pass. They enter the upper and mesial part of THE HIND-BRAIN 
933 
the medullary substance of the hemispheres, beneath the ala lobuli centralis and 
the fraenulum, and pass to a great extent into the interior of the corpus dentatum, 
though some of their fibres wind around it and reach the gray cortical matter, 
especially of the inferior surface. 
There are both afferent and efferent fibres in the superior peduncle, and the 
fibres are in two bundles (Fig. 600). The fibres to the cerebrum are axones of cells, 
most of which are situated in the corpus dentatum, but some of the fibres to the 
cerebrum come from the Purkinje cells of the cerebellar cortex, and probably 
also a few come from the smaller nuclei in the central white substance. The 
majority of the fibres decussate below the corpora quadrigemina, and pass to 
the opposite red nucleus of the tegmentum, from which a relay is prolonged 
through the optic thalamus to the cerebral cortex. The fibres of the second group 
take origin in the opposite red nucleus and end in the corpus dentatum (Santee). 
STRIAE 
ACUSTICAE 
Fig. 599.-The peduncles of the cerebellum. On the left the three peduncles have been cut at their entrance 
into the cerebellum; on the right side they are shown penetrating the cerebellar hemisphere. (Poirier and 
Charpy.) 
The Valve of Vieussens or Superior Medullary Velum (velum medullare 
anterius) (Figs. 574, 584,604, and 606).-Stretched across from one superior cere- 
bellar peduncle to the other is a thin, transparent lamina of white matter, the 
valve of Vieussens; on to the dorsal surface of its lower half the folia of the lingula 
are prolonged. It helps to form with the superior peduncles the roof of the upper 
part of the fourth ventricle, and is continuous with the central white stem of the 
cerebellum. It is narrow above, where it passes beneath the corpora quadri- 
gemina, and broader below, at its connection with the white substance of the 
superior worm of the cerebellum. A slightly elevated ridge descends upon the 
upper part of the valve from between the lower corpora quadrigemina, and on 
either side of this may be seen the fourth nerve. The majority of the fibres of 
the superior medullary velum are chiefly longitudinal fibres, passing between the 
cerebrum and the worm of the cerebellum. What is known as the antero-lateral 
ascending cerebellar tract of Gowers is said by Hoche to pass to the worm by way of 934 
THE NERVOUS SYSTEM 
the superior velum. The velum also contains some commissural fibres and decus- 
sating fibres of the roots of the fourth nerves. 
The Middle Peduncles or Crura ad Posterior (brachia pontis) are the largest 
of the three pairs. They consist of a mass of curved fibres, which, as already 
described, pass to the pons and fovea, comprises most of the transverse fibres of 
the pons. These tracts are both afferent and efferent, and the middle peduncle 
emerges from the cerebellum at the anterior notch, between the margins of the 
great horizontal fissure. The fibres of the middle peduncle (Fig. 600J rise from 
Fig. 600.-Diagram showing the origin and course of the fibres of the peduncles of the cerebellum. 
(Edinger.) 
all portions of the cortex of the cerebellum. In the peduncle the fibres effect a 
crossing, so that fibres from the anterior part of the hemisphere pass to the 
posterior part of the pons, and fibres from the posterior portion of the hemisphere 
pass to the anterior portion of the pons. The fibres approach the median line 
and terminate on both sides of the raph^ in the nuclei pontis and the nuclei of 
the formatio reticularis (Cajal). The balance of the fibres are "axones of cell- 
bodies, situated mainly in the opposite nucleus pontis."1 These fibres "form a 
segment in the indirect motor paths contained above the pons, in the medial 
' Anatomy of the Brain and Spinal Cord. By Harris E. Santee. THE HIND BRAIN 
935 
and lateral fifths, and the intermediate bundle of the crusta. Collaterals from 
both groups of fibres ascend and descend in the pons. They run upward with 
both crustae, but chiefly with the opposite one; and they accompany the fillet 
and posterior longitudinal bundle of the same side to the nuclei of the third, 
fourth, and sixth cranial nerves."1 
The Inferior Peduncles or Crura ad Medullam (corpora restiformia) connect the 
cerebellum with the medulla oblongata. The fibres (Fig. 600) are both afferent 
and efferent and begin in the gray cortex of the upper surface of the cerebellar 
hemispheres and the worm. They descend in a direction downward and inward, 
from part of the lateral walls of the fourth ventricle, reach the medulla, and 
become the restiform bodies, which will be subsequently described (p. 941). The 
following are the chief sets of fibres in the inferior peduncles: 1. The direct 
cerebellar tract, which takes origin in Clarke's column of the spinal cord and 
terminates in the superior worm of the cerebellum. 2. The external arciform 
fibres, which rise in the gracile and cuneate nuclei of the medulla and terminate 
in the vermis superior. The posterior or uncrossed fibres terminate on the same 
side, the anterior or crossed fibres on the opposite side. 3. The acustico-cerebellar 
tract. These fibres originate from the nucleus of the auditory nerve in the floor of 
the fourth ventricle, and terminate in the opposite nucleus fastigii and nucleus 
globosus of the cerebellum. 4. Fibres which pass between the lateral nucleus of 
the medulla oblongata and the corresponding side of the cerebellar cortex. 5. The 
Spider-like cell. 
Tendril fibre. 
Basket-cell. 
Cell of Golgi. 
Axon. 
Moss fibre. 
Punctated 
molecular 
layer. 
Cell of Purkinje. 
Fig. 601.-Diagrammatic representation of the cells of the cerebellum. A. Molecular layer. B. Nuclear 
layer. C. White matter. (Modified from Foster's Physiology.) 
descending cerebellar tract, which originates in the cerebellar cortex and which 
passes down by way of the restiform body of the medulla and the antero-lateral 
column of the spinal cord and reaches the anterior gray horn of the cord. 6. The 
internal arciform fibres, which pass between the cerebellar cortex and the opposite 
olivary body of the medulla (the cerebelio-olivary tract). Santee emphasizes the 
fact that most of the fibres which emerge from the cerebellum in the middle and 
inferior peduncles are "axones of Purkinje's cells; they connect the cerebellum 
with the motor nuclei of cranial and spinal nerves."2 
1 Anatomy of the Brain and Spinal Cord. By Harris E. Santee. 2 Ibid. 936 
THE NERVOUS SYSTEM 
The Fibres Proper of the Cerebellum.-The fibrae propriae of the cerebellum are 
of two kinds: (1) commissural fibres, which cross the middle line to connect the 
opposite halves of the cerebellum, some at the anterior part and others at the 
posterior part of the vermiform process; (2) association fibres, which are antero- 
posterior fibres connecting adjacent laminae with each other. , 
The Gray Matter of the Cerebellum.-The gray matter of the cerebellum is found 
in two situations: (1) on the surface, forming the cortex; (2) as independent masses 
in the interior. 
1. The Cortex of the Cerebellum (substantia cortical is) presents a characteristic 
foliated appearance, due to the series of laminae which are given off from the 
central white matter; these in their turn give off secondary laminae, which are 
covered with gray matter. This arrangement gives to the cut surface of the organ 
a foliated appearance (Fig. 598). Externally, the cortex is covered by pia matter; 
internally, is the medullary centre, consisting mainly of nerve-fibres. 
Microscopic Appearance of the Cortex (Figs. 601 and 602).-The cortex 
presents a remarkable structure, consisting of two distinct layers-viz., an external 
or superficial molecular layer, and an internal, deep, nuclear, rust-colored, or granular 
layer. Between the two layers is an incomplete stratum of the characteristic cells 
of the cerebellum, the corpuscles of Purkinje. 
The external, superficial gray or molecular layer (Figs. 601 and 602) consists of 
fibres and cells. The nerve-fibres are delicate fibrillae, and are derived from the fol- 
lowingsources: (a) the dendrites and axone collaterals of Purkinje's cells; (6) fibres 
from cells in the granular layer; (c) fibres from the central white substance of the 
cerebellum; (d) fibres derived from cells in the molecular layer itself. In addition 
to these are other fibres, which have a vertical direction. These are the processes 
of large glia-cells, situated in the granular layer. They pass outward to the 
periphery of the gray matter, where they expand into little conical enlargements, 
which form a sort of limiting membrane beneath the pia mater, analogous to the 
membrana limitans interna in the retina, formed by the fibres of Muller. 
The cells of the molecular layer are small, and are arranged in two strata, an 
outer and an inner. They all possess branching axis-cylinder processes; those of 
the inner layer run for some distance horizontally, i. e., parallel with the surface of 
the folia, giving off at intervals collaterals, which pass in a vertical direction 
toward the cell-bodies of Purkinje's corpuscles, around which they become enlarged 
and ramify like a basket. Hence these cells of the inner portion of the external 
layer are named basket-cells (Fig. 601). 
The cells or corpuscles of Purkinje (Fig. 602) are flask-shaped cells, situated at the 
junction of the molecular and granular layers, their bases resting against the latter. 
From the bottom of each flask one axis-cylinder process arises; this passes through 
the granular layer, and, becoming medullated, is continued as a nerve-fibre in 
the medullary substance beneath. This axone gives off fine collaterals as it 
passes through the granular layer, some of which run back into the molecular 
layer. From the neck of the flask numerous dendrites are given off, which branch 
in an antler-like manner in the molecular layer and terminate in free extremities. 
The internal, rust-colored, nuclear or granular layer (Figs. 601 and 602) is charac- 
terized by containing numerous small nerve-cells or granules of a reddish-brown 
color, together with many nerve-fibrils. Most of the cells are nearly spherical and 
provided with short dendrites, which spread out in a spider-like manner in the gran- 
ular layer. Their axones pass outward into the molecular layer, and, bifurcating 
at right angles, run horizontally for some distance. In the outer part of the gran- 
ular layer are also to be observed some larger cells, of the type termed Golgi cells 
(Fig. 601). Their axones undergo frequent division as soon as they leave the 
nerve-cells, and pass into the granular layer, while their dendrites ramify chiefly 
in the molecular layer. THE HIND-BRAIN 
937 
Finally, in the gray matter of the cerebellar cortex fibres are to be seen which 
come from the white centre and penetrate the cortex. The cell origin of these 
fibres is unknown, though it is believed that it is probably in the gray matter of 
the spinal cord. Some of these fibres end in the granular layer, by dividing into 
numerous branches, on which are to be seen peculiar moss-like appendages; hence 
they have been termed by Ramon y Cajal the moss fibres (Fig. 601); they form 
an arborescence around the cells of the granular layer. Other fibres derived 
from the medullary centre can be traced into the molecular layer, where their 
branches cling around the dendrites of Purkinje's cells, and hence they have been 
named the clinging or tendril fibres (Fig. 601). 
■External gray or 
cellular layer. 
Corpuscles of Purkinje. 
■Internal or rust- 
colored layer. 
White substance. 
Fig. 602.-Vertical section through the gray matter of the human cerebellum. Magnified about 100 diameters. 
(Klein and Noble Smith.) 
2. The Independent Centres of Gray Matter in the Cerebellum are four in number 
on each side: one is of large size, and is known as the corpus dentatum; the other 
three, much smaller, are situated near the middle of the cerebellum, and are known 
as the nucleus emboliformis, nucleus globosus, and nucleus fastigii. 
The corpus dentatum or ganglion of the cerebellum (nucleus dentatus) is a gray 
nucleus situated a little to the inner side of the centre of the stem of the white 
matter of the hemisphere. It consists of an irregularly folded lamina of a grayish- 
yellow color, containing white fibres, and presenting on its antero-internal aspect 
an opening, the hilum (hilus nuclei dentati), from which most of the fibres of the THE NERVOUS SYSTEM 
938 
superior cerebellar peduncle emerge. The nucleus emboliformis is a mass of gray 
matter placed immediately to the inner side of the corpus dentatum, and partly 
covering its hilum. The nucleus globosus is an elongated mass of gray matter, 
directed antero-posteriorly, and placed to the inner side of the preceding. The 
nucleus fastigii is somewhat larger than the other two, and is situated close to the 
middle line at the anterior end of the superior vermiform process, and immediately 
over the roof of the fourth ventricle, from which it is separated by a thin layer 
of white matter. It is known as the roof nucleus of Stilling. 
Weight of the Cerebellum.-Its average weight in the male is about 5 oz., 4 drs. 
It attains its maximum weight between the twenty-fifth and fortieth years, its 
increase in weight after the fourteenth year being relatively greater in the female 
than in the male. The proportion between the cerebellum and cerebrum is, in the 
male, as 1 to 8|, and in the female as 1 to 8. In the infant the cerebellum is 
proportionately much smaller than in the adult, the relation between it and the 
cerebrum being, according to Chaussier, between 1 to 13, and 1 to 26; by Cruveil- 
hier, the proportion was found to be 1 to 20. 
V. The Medulla Oblongata (Myelencephalon) (Figs. 557, 594, 603, 604). 
The medulla oblongata, known also as the spinal bulb, is the lowest division of 
the encephalon, and is continuous with the spinal cord. It is, in fact, the intra- 
cranial portion of the spinal cord. It is developed from the fifth cerebral vesicle, 
the cavity of which forms the lower half of the fourth ventricle. It extends from 
the lower margin of the pons Varolii to a plane passing transversely just below 
the decussation of the pyramids, at which level the spinal cord commences. This 
plane corresponds to the lower margin of the foramen magnum. The upper limit 
of the medulla is marked off from the pons 
Varolii on its ventral aspect by the abrupt 
lower margin of the latter. 
The medulla oblongata is directed from 
above obliquely downward and backward; 
its ventral surface rests on the basilar groove 
of the occipital bone, while its dorsal surface 
is received into the fossa between the hemi- 
spheres of the cerebellum, and forms the 
lower part of the floor of the fourth ventricle. 
It is pyramidal in shape, its broad extremity 
directed upward, its lower end being narrow 
at its point of connection with the cord. It 
measures an inch in length, three-quarters 
of an inch in breadth at its widest part, and 
half an inch in thickness. Its surface is 
marked, in the median line, in front and be- 
hind, by an anterior and a posterior median 
fissure (fissura mediana anterior and fissura 
mediana posterior), which are continuous with similar fissures on the anterior and 
posterior surfaces of the cord, but neither one of them extends the entire length 
of the bulb. The anterior fissure contains a fold of pia mater, and terminates just 
below the pons in a cul-de-sac, the foramen caecum of Vicq d'Azyr. It is interrupted 
at its lower part by some bundles of fibres, which cross obliquely from one side to 
the other, forming the decussation of the pyramids (decussatio pyramidum) (Figs. 
594 and 605). The posterior fissure is a deep but narrow fissure, continued upward 
to about the middle of the medulla. As it ascends its depth diminishes, and about 
the middle of the posterior surface of the medulla the central canal of the cord 
Middle 
peduncle of 
cerebellum. 
Fig. 603.-Medulla oblongata and pons Varolii. 
Anterior surface. THE MEDULLA OBLONGATA 
939 
opens, and the lips of the shallow posterior fissure diverge and bound the triangular 
opening, which is the lower portion of the floor of the fourth ventricle (Figs. 604 
and 606). As the lower half of the medulla contains the central canal of the cord, 
it is called the closed portion; the upper half of the medulla is above the opening 
of the central canal and is called the open portion. 
These two fissures divide the medulla into two symmetrical halves, each half 
presenting elongated eminences, which are continuous with the columns of the cord. 
By taking the lines along which some of the cranial nerves emerge from the 
medulla as landmarks, the surface of this portion of the nervous system may be 
divided into three columns, in the same way as the spinal cord is divided into three 
columns by the lines corresponding to the points of exit of the anterior and poste- 
rior roots of the spinal nerves. The hypoglossal nerve-roots arise from a furrow 
on the antero-lateral surface of the medulla, which is known as the antero-lateral 
furrow, or the ventro-lateral groove (sulcus lateralis anterior). There is no furrow 
on the cord corresponding with this medullary furrow. The roots of the glosso- 
pharyngeal and pneumogastric nerves and the accessory root of the spinal accessory 
nerve lie in a furrow upon the postero-lateral surface of the medulla. This furrow 
is called the postero-lateral furrow or dorso-lateral groove (sulcus lateralis posterior). 
This groove is the continuation of the postero-lateral fissure of the cord. It is not 
straight, but turns forward as it ascends. At the termination of this groove ante- 
riorly the seventh and eighth cranial nerves emerge. At the lower portion of the 
medulla the groove ceases for a short distance as the direct cerebellar tract passes 
from the lateral to the posterior surface of the bulb. The anterior column com- 
prises that portion which is situated between the anterior median fissure and the 
antero-lateral furrow; this column is called the anterior pyramid or simply the 
pyramid (Fig. 603). The lateral column comprises that portion which is situated 
between the antero-lateral and the postero-lateral furrows. In the lower part 
of the medulla this column is single, and is called the lateral tract; but in the 
upper part an oval-shaped body comes forward between it and the pyramid, and 
pushes aside the lateral tract. This is called the olivary body (Fig. 603) The 
posterior column (Fig. 604) comprises that portion which is situated between the 
postero-lateral furrow and the posterior median fissure. It is marked by slight 
furrows dividing it into smaller columns, and these in the lower part of the 
medulla are named, from without inward, the fasciculus of Rolando, the fasciculus 
cuneatus and the fasciculus gracilis; in the upper part of the medulla, the fasciculus 
of Rolando and the fasciculus cuneatus appear to become fused together and seem 
to form the single body, called the restiform body (Fig. 604). As a matter of fact 
the restiform body is not so formed (p. 941). 
The Pyramid (pyramis medullae oblongatae) (Figs. 594 and 603).-The 
pyramid is a pyramidal bundle of white matter. A pyramid is placed one 
on either side of the anterior median fissure, and separated from the olivary 
body by a slight depression, from which the roots of the hypoglossal nerve 
emerge (antero-lateral furrow). At the lower border of the pons these bodies 
are somewhat constricted and are here crossed by a band of arched fibres, 
the ponticulus of Arnold; below this they become enlarged, and then taper as 
they descend to their lower extremity. The fibres of which compose these 
pyramids may be arranged in two bundles: an outer, continuous below with 
the direct or uncrossed pyramidal tract of the anterior column of the same 
side of the spinal cord, and an inner, continuous with the crossed pyramidal tract 
of the lateral column of the opposite side of the cord (Fig. 605). As will be 
subsequently mentioned, the direct pyramidal tract in the cord lies next to the 
anterior median fissure, but as the crossed pyramidal tract of the cord ascends to 
the medulla it decussates with its fellow of the opposite side across the anterior 
median fissure, and so displaces laterally the direct pyramidal tract, and ascends, 940 
THE NERVOUS SYSTEM 
after decussation, through the medulla to its inner or mesial side. This decussa- 
tion is usually spoken of as the decussation of the pyramids (Figs. 594 and 605), 
but it must be borne in mind that it is only a portion of the fibres of the 
pyramid (90 percent, of them) which decussate; namely, those derived from the 
crossed pyramidal tract of the cord; the outermost fibres, derived from the anterior 
column of the cord, do not decussate. Each pyramid enters the substance of the 
pons in one bundle, and may be traced through it, after breaking up into several 
smaller fasciculi, into the corresponding crus cerebri. 
PONS_ 
VENTRAL PLANE 
' OF OBLONGATA 
MIDDLE PLANE 
OF OBLONGATA 
.DORSAL PLANE 
OF OBLONGATA 
•Restiform body. 
'LONGITUDINAL 
COM MISSU RAL 
■Clara. 
Cuneate tubercle. 
CORD 
Fig. 604.-Posterior surface of the medulla 
oblongata. 
Fig. 605.-Diagram to show the crossing of the pyramids 
(red) and of the lemniscus (blue). (Testut.) 
The Lateral Column or Lateral Area.-The lateral column or area is 
between the antero-lateral and postero-lateral furrows. In the lower part of 
the medulla it is of the same width as the lateral column of the cord, and 
appears on the surface to be a direct continuation of it. As a matter of fact it is 
only a part of the lateral column of the spinal cord which is continued upward into 
this column; for the crossed pyramidal tract passes into the pyramid of the oppo- 
site side, and the direct cerebellar tract of the lateral column of the cord passes into 
the restiform body. The rest of the lateral column of the cord, that is to say, the 
antero-lateral ground bundle {fasciculus proprius anterolateralis} and the antero- 
lateral cerebellar tract {fasciculus anterolateralis superficialis), can be traced THE MEDULLA OBLONGATA 
941 
upward into this area. In the upper part of the medulla, the lateral tract, on 
account of the interpolation of the olivary body, becomes almost concealed by 
this body. 
The Olive, Olivary Body or Olivary Eminence (oliva) (Figs. 586, 589, and 603). 
-The olivary body or eminence is a prominent oval mass, bulging from the 
upper part of the lateral column of the medulla. It is situated on the outer side 
of the pyramid, from which it is separated by the slight groove, along which 
the fibres of the hypoglossal nerve emerge. It is separated externally from the 
restiform body by a longitudinal, narrow band of fibres, prolonged upward from 
the lateral tract, and by the groove, from which the glosso-pharyngeal, pneu- 
mogastric, and spinal accessory nerves arise. It is equal in breadth to the 
pyramid; it is broader above than below, and is about half an inch in length, 
being separated above from the pons Varolii by a slight depression, in which a 
band of arched fibres is sometimes to be seen. Numerous white fibres, superficial 
or external arciform or arcuate fibres (Fig. 607), are seen winding across the lower 
half of the pyramid and the olivary body to enter the restiform body. The 
olivary body is formed by the olivary nucleus of the medulla (Fig. 607), a lamina 
of gray matter, the surface of which is covered by a very thin layer of white 
matter. 
The Funiculus or Fasciculus of Rolando (jasciculus lateralis) (Fig. 604).-The 
fasciculus of Rolando is a longitudinal prominence on the outer side of the lateral 
tract. It begins at the lower end of the medulla by a tapering extremity, and has, 
apparently, no corresponding column in the cord. It gradually enlarges as it 
ascends, and forms, at a level with the lower border of the olivary body, a consid- 
erable prominence, known as the tubercle of Rolando (tuberculum Rolandi) (Fig. 
607). This is caused by the substantia gelatinosa of Rolando of the cord gradually 
finding its way to the surface, so as to form a prominence there. About half an 
inch below the pons the fasciculus of Rolando appears to blend with the fasciculus 
cuneatus. In front, it is separated from the lateral tract by a distinct groove, the 
continuation upward of the postero-lateral groove of the cord; behind, the 
separation from the fasciculus cuneatus is much less distinct. 
The Wedge-shaped or Cuneate Funiculus or the Fasciculus Cuneatus (Fig. 
604) is the direct continuation upward of the postero-lateral column (tract of 
Burdach) of the cord. It is situated between the fasciculus of Rolando and the fas- 
ciculus gracilis. It enlarges as it ascends, and forms, opposite the lower extremity 
of the fourth ventricle, a slight eminence or enlargement, the cuneate tubercle 
(tuberculum cuneatum) (Fig. 604), which is marked only in children. Above this 
point it disappears from the surface. 
The Slender Funiculus or the Fasciculus Gracilis (Fig. 604) is the direct 
continuation upward of the postero-median column of the cord (tract of Goll). It 
is a narrow white band, placed parallel to and along the side of the posterior 
median fissure. It is separated from the fasciculus cuneatus by a slight groove, 
continuous with that on the surface of the cord, which marks off the postero- 
median column. At first the fasciculi of the two sides lie in close contact on 
either side of the posterior median fissure. Opposite the apex of the fourth 
ventricle each presents an enlargement, the clava (Fig. 604); they then diverge 
and form the lateral boundaries of the lower part of the fourth ventricle, and 
gradually tapering off become no longer .traceable. The surface prominence 
of the fasciculus gracilis is formed by the gray nucleus beneath. This nucleus 
is known as the nucleus fasciculi gracilis. 
The Restiform Body (corpus restijorme) (Fig. 604).-The upper part 
of the posterior area of the medulla is occupied by the restiform body. It 
appears, at first sight, as if this body were the direct continuation upward of 
the fasciculus cuneatus and the fasciculus of Rolando, and it was formerly THE NERVOUS SYSTEM 
942 
described as such. This, however, is not so, for the restiform body is largely 
formed by a set of fibres, the superficial or external arciform or arcuate fibres 
(Fig. 607), which issue from the anterior median fissure and will presently be 
described. They pass laterally over the pyramid and olive, and assist in form- 
ing the restiform body. There is also a narrow strand of fibres, derived from 
the lateral column of the cord, the direct cerebellar tract (fasciculus cerebello- 
spinalis), which joins the above-mentioned arcuate fibres. These two sets of 
fibres, reinforced by the internal arcuate fibres from the opposite side of the 
medulla, form the restiform body. 
The restiform bodies are the largest prominences of the medulla, and are 
placed between the lateral tracts in front and the fasciculus cuneatus behind, from 
both of which they are separated by slight grooves. As they ascend they diverge 
from each other, assist in forming the lower part of the lateral boundaries of the 
fourth ventricle, and then enter the corresponding hemisphere of the cerebellum, 
forming its inferior peduncles. 
The Posterior Surface of the Medulla Oblongata (facies posterius) (Fig. 
604).-The posterior surface of the medulla oblongata forms part of the floor of 
the fourth ventricle (Fig. 606). This portion is of a triangular form, bounded 
on each side by the diverging fasciculi graciles and cuneati and restiform bodies. 
The divergence of these two fasciculi and of the restiform bodies, together with the 
opening out of the posterior fissure and central canal of the spinal cord, displays 
in the floor of the ventricle the gray matter of the medulla, which is continuous 
below with the gray matter of the cord. In the middle line is seen a longitudinal 
furrow, which divides this part of the ventricle into right and left halves, and is 
continuous below with the central canal of the cord. 
The Arciform or Arcuate Fibres (Fig. 607).-The arciform or arcuate fibres, which 
have been mentioned as forming part of the restiform body, are found in the upper 
half of the medulla, crossing its surface and also traversing its substance. They 
are divided for purposes of description into two sets-external and internal. The 
external or superficial arciform or arcuate fibres (fibrae arcuatae externae) have already 
been alluded to as crossing the pyramid and olivary body on each side. They 
emerge from the anterior median fissure, and if traced into it are found to enter 
the raphe and cross to the opposite side, after which their further course is a matter 
of some doubt. After emerging from the anterior median fissure they cross the 
pyramid and olivary body, often concealing from view the upper part of the 
cuneate and Rolandic fasciculi, and enter the restiform body. As they cross the 
olivary body they are reinforced by some of the internal arciform fibres, which 
come to the surface on the inner side of, or through, this structure. The internal 
arciform or arcuate fibres (fibrae arcuatae internae) are described with the microscopic 
anatomy of the medulla. 
It is advisable, at this stage, to take up the consideration of the cavity of the 
fourth ventricle, an acquaintance with which will render the description of the 
internal structure of the medulla oblongata more intelligible. 
The Fourth Ventricle (Ventriculus Quartus) (Fig. 606) 
The fourth ventricle is the cavity common to the metencephalon, and the myel- 
encephalon is in the pons and medulla oblongata and is anterior or ventral to the 
cerebellum. It is lozenge- or diamond-shaped; that is to say, it is composed of two 
triangles, with their bases in contact. The sides of the lower triangle are formed 
by the divergence of the fasciculi graciles, fasciculi cuneati, and restiform bodies 
of the medulla on either side. As these columns pass upward in the medulla they 
turn outward from the median line, and, diverging from each other, form the 
lateral boundaries of the lower half of the fourth ventricle. In like manner the THE FOURTH VENTRICLE 
943 
sides of the upper triangle are formed by the convergence of the superior peduncles 
of the cerebellum. These peduncles are separated below by a somewhat wide 
interval, but as they pass upward and forward toward the corpora quadrigemina 
they gradually converge and ultimately come into contact with each other. This 
cavity is therefore bounded laterally on each side by the superior peduncle of the 
cerebellum in its upper half, and by the fasciculus gracilis, the fasciculus cuneatus, 
and the restiform body in its lower half. It presents four angles. The upper 
angle reaches as high as the upper border of the pons, and corresponds with the 
lower opening of the aqueduct of Sylvius, by which this ventricle communicates 
with the third ventricle (Fig. 587). The lower angle is on a level with the lower 
border of the olivary body, and is continuous with the central canal of the spinal 
cord. From the resemblance that it bears to the point of a writing pen it has been 
named the calamus scriptorius. Its lateral angles extend for some distance between 
the medulla and the cerebellum, each forming a pointed lateral recess. 
The Roof or Posterior Wall of the Fourth Ventricle.-The roof of the fourth 
ventricle is formed from above downward by the following structures: a part of 
the superior peduncles of the cerebellum, the anterior or superior medullary velum, 
the posterior or inferior medullary velum, the tela chorioidea inferior, the obex, and 
the lingula. The superior half of the roof meets the inferior half at an acute angle 
to form the tent of the fourth ventricle (fastigium). 
The Superior Peduncles of the Cerebellum (brachia conjunctiva cerebelli) (Figs. 
557, 598, 599, 604, and 606).-The superior peduncles of the cerebellum, when 
they emerge from the medullary substance of its hemispheres, pass upward and 
forward, forming the lateral boundaries of the upper half of the fourth ventricle, 
but, converging as they approach the corpora quadrigemina, the mesial portions 
of the peduncles form a part of the roof of the cavity, in consequence of the ven- 
tricle extending to a slight extent underneath the peduncles. 
The Anterior or Superior Medullary Velum (Valve of Vieussens) (velum medullare 
anterius) (Figs. 584, 596, 605, and 606).-In the angular interval left between the 
two superior peduncles is a thin lamina of white matter, continuous with the white 
centre of the cerebellum, which bridges across from one peduncle to the other, 
and so completes the roof of the superior part of the ventricle. This is the superior 
medullary velum or valve of Vieussens. Its dorsal surface is covered by the folia 
of the lingula, already described (p. 928). 
The Posterior or Inferior Medullary Velum (velum medullare posterius).-The pos- 
terior or inferior medullary velum is a thin layer of white substance, prolonged 
from the white centre of the medulla on either side of the nodule, which assists in 
forming a part of the roof of the fourth ventricle, stretching over it toward its 
lateral angles. It is continuous with the white substance of the cerebellum by 
its convex edge, while its thin concave margin is apparently free. In reality, 
however, it is continuous with the epithelium of the ventricle, which is prolonged 
downward from the velum to the edge of the lingula. 
The Tela Chorioidea Inferior (tela chorioidea ventriculi quarti).-The tela chorioidea 
inferior is a layer of pia mater which covers in the lower part of the fourth ventricle 
below the inferior medullary velum. Superiorly it is reflected on to the under 
surface of the cerebellum, while inferiorly it is continued on to the restiform bodies 
and lower part of the medulla. This part of the roof of the ventricle contains no 
nervous matter, but consists merely of the ventricular epithelium covered by pia 
mater. The tela chorioidea inferior, like the velum interpositum or tela chorioidea 
superior (p. 855), really consists of two layers, which become more or less adherent, 
viz., that covering the under surface of the cerebellum and that covering the epithe- 
lium. It also possesses on each side a choroid plexus (plexus chorioideus ventriculi 
quarti), which projects into the ventricular cavity invaginating before it the epithelial 
lining. Each plexus consists of a vertical portion which extends forward, near the 944 
THE NERVOUS SYSTEM 
middle line, from the foramen of Majendie, and of a transverse part, which passes 
outward into the lateral recess of the ventricle as far as the foramina of Key and 
Retzius. The two plexuses present the form of a T, the vertical limb of which is, 
however, double, || . The tela does not form a complete membrane, for in it 
there are three openings: one in the middle line at the inferior angle of the ven- 
tricle, just above the position of the opening of the central canal of the cord; this 
is the foramen of Majendie (apertura medialis ventriculi quartiy, the other two are 
at the right and left extremities of the lateral recesses of the ventricle, and each is 
named the foramen of Key and Retzius (apertura lateralis ventriculi quarti) (see 
pp. 852 and 853). Through these foramina the ventricles of the brain commu- 
nicate with the subarachnoid space. 
The Obex.-The obex is a thin, triangular lamina of gray matter, continuous 
below with the anterior gray commissure of the cord, which fills in the angle 
between the two diverging fasciculi, graciles for a short distance. 
The Ligula.-The ligula (taenia ventriculi quarti) are narrow bands of white 
matter, which project from the internal border of the funiculi graciles. They at 
first run upward and forward, and then turn outward over the restiform bodies, 
as far as the lateral recesses of the ventricle. Their inner borders are continuous 
with the epithelial roof of the ventricle. 
The Floor or Anterior Wall of the Fourth Ventricle (fossa rhomboidea) 
(Figs. 599, 604, and 606).-The floor of the fourth ventricle is rhomboidal in shape, 
•Corpora quadrigemina. 
Superior peduncle 
of cerebellum. 
Valve of Vieussens. 
Fasciculus teres. 
Locus caruleus.' 
Fovea superior.. 
Conductor son or us. 
•Stria acustica. 
Trigonum hypoglossi. 
Ala cinerea.- 
Trigonum acustici. 
Clava. 
Tuberculum cuneatum. 
•Lateral column. 
Fig. 606.-Floor of the fourth ventricle. Diagrammatic. 
and is traversed by a vertical median fissure (sulcus longitudinalis fossae rhom- 
boideae), which below is continuous with the central canal of the spinal cord. At 
the junction of the fourth ventricle with the central canal of the cord is a dilata- 
tion or ampulla called the ventricle of Arantius. At the widest part of the fourth 
ventricle, opposite the level of the lateral recesses, it is marked by some trans- 
verse white lines, the striae medullares or striae acusticae. These consist of white 
fibres, which emerge from the longitudinal sulcus, and pass outward across the 
floor of the ventricle. Most of the striae acusticae take origin from cochlear 
nucleus, but some arise from the cochlear root. Most of them pass to the trape- INTERNAL STRUCTURE OE THE MEDULLA OBLONGATA 
945 
zium and lateral fillet of the opposite side, but some become external arciform 
fibres (Koelliker). These striae divide the floor of the ventricle into two triangles, 
inferior and superior. 
The Inferior Triangle (Fig. 606).-The inferior triangle, or lower or posterior 
half of the floor, presents above an angular groove, the fovea inferior, the apex of 
which is at the striae, while the two limbs diverge below, and form the sides of a 
triangular dark area, termed the alacinerea, which becomes elevated into a promi- 
nence below (eminentia cinerea). This area corresponds with the nuclei of the 
vagus and glosso-pharyngeal nerves, and is therefore termed the trigonum vagi. 
A second triangular area lies between the inner limb of the fovea and the median 
sulcus; its base is directed upward, and limited by the striae medullaris. It is 
termed the trigonum n. hypoglossi, because it corresponds in position to the tract of 
nerve-cells from which the hypoglossal nerve takes origin. A third triangular area 
to the outer side of the fovea inferior is named the trigonum acustici (area acustica). 
It lies between the groove forming the outer boundary of the fovea inferior and 
the lateral wall of the ventricle, and, like the trigonum hypoglossi, has its base 
directed upward. Here it is continuous with a prominence, the tuberculum acusti- 
cum, which extends into the anterior part of the floor of the ventricle. 
The Superior Triangle (Fig. 606).-The superior triangle or upper or anterior 
half of the floor of the fourth ventricle, i. e., the part above the striae medullaris, 
presents in the middle line the continuation of the median longitudinal sulcus. 
On either side of this is a spindle-shaped longitudinal eminence, prominent in its 
centre, but less so above and below. This is the eminentia teres or fasciculus 
teres (colliculus facialis), and is produced by an underlying bundle of white fibres, 
the fasciculus teres (eminentia medialis), formed, in part at all events, by the fibres 
of the facial nerve. Immediately above and to the outer side of the eminentia 
teres is an angular depression, the fovea superior; this is sometimes crossed by 
a whitish band of fibres, the conductor sonorus, which is connected below with 
the striae medullares of the same side. Above the fovea is a bluish depressed 
area, the locus caeruleus. Its color is due to some pigmented nerve-cells, showing 
through the white covering of the floor. These pigmented cells are named the 
substantia ferruginea, and in them one of the roots of the fifth nerve terminates. 
The Lining Membrane.-The lining membrane of the fourth ventricle is con- 
tinuous above with that of the third ventricle, through the aqueduct of Sylvius 
(p. 912), and below with that of the central canal of the spinal cord. The cavity 
of the ventricle communicates below with the subarachnoidean space by means 
of the foramen of Majendie and the foramina of Key and Retzius, already 
described. 
The Internal Structure of the Medulla Oblongata (Figs. 607, 608, 609,610, 611,612). 
If the cranial nerves emerging from the medulla are traced into its substance, 
it will be seen that they divide each half of the bulb into three wedge-shaped areas, 
which are named the anterior, lateral, and posterior areas of the medulla, and each 
of which corresponds to one of the subdivisions already described on the surface 
of this portion of the encephalon. 
The Anterior Area.-The anterior area comprises that portion which is situ- 
ated between the anterior median fissure and the fibres of superficial origin of the 
hypoglossal nerve. On the surface of the medulla this area corresponds to the 
pyramid (Fig. 607). 
The Lateral Area.-The lateral area is situated between the fibres of super- 
ficial origin of the hypoglossal nerve on the one hand, and the fibres of superficial 
origin of the glosso-pharyngeal pneumogastric and spinal accessory nerves on the 
other. On the surface of the medulla, in its lower part, this area is single, and is 946 
THE NERVOUS SYSTEM 
called the lateral tract; but in the upper part an oval-shaped body, the olivary 
body, comes forward between it and the pyramid, pushing; aside the lateral tract 
(Fig. 607). 
The Posterior Area.-The posterior area comprises that portion which is situ- 
ated between the fibres of superficial origin of the glosso-pharyngeal, pneumogas- 
tric, and spinal accessory nerves, and the posterior median fissure. On the surface 
of the medulla this area is marked by slight furrows, splitting it up into smaller 
columns; those in the lower part of the medulla are named, from without inward, 
the fasciculus of Rolando, the fasciculus cuneatus, and the fasciculus gracilis; in 
the upper part of the medulla they are replaced by the restiform body. Finally, 
the halves of the medulla are separated from each other by a median septum or 
raphd (Fig. 607). 
Vagus nuclei. 
Ligula. 
Fasciculus Solitarius. 
Nucleus ofJ 
fasciculus teres. 
Hypoglossal 
nucleus. 
Nucleus gracilis. 
Nucleus cuneatus. 
.Corpus restiforme. 
Nucleus ambig. 
Nucleus or 
.tubercle of 
Rolando. 
Raphe- 
-Ascending root of 
fifth nerve. 
Formatio reticularis- 
Continuation of antero- 
lateral ground-bundle 
Vagus root. 
'Arciform fibres. 
-Nucleus lateralis. 
Accessory olivary nuclei- 
Olivary nucleus. 
Hypoglossal nerve. 
An terior median fissure. 
■Nucleus of ext. arc. fibres. 
'External arciform fibres. 
Fig. 607.-Section of the medulla oblongata at about the middle of the olivary body. (Schwalbe.) 
Each of these three areas is made up of gray and white matter. The giay 
matter is derived for the most part from that of the cord. In like manner the 
white matter is partly made up of longitudinal fibres continuous with those of 
the cord, and partly of transverse fibres which intersect them. 
In order to understand the internal structure of the medulla, it is necessary to 
describe the appearances as they are seen in the upper and lower portions of the 
medulla, since they differ considerably in these two parts. 
The Lower Part of the Medulla (Figs. GOS and 609).-The hist change 
in the internal structure is caused by the passage of the fibres of the crossed 
pyramidal tract obliquely through the gray matter of the anterior horn. As 
stated above, the pyramid is composed of fibres derived from the direct 
pyramidal tract of the anterior column of the cord of the same side, and 
from the crossed pyramidal tract of the lateral column of the opposite half 
of the cord. Those fibres which are derived from the direct pyramidal tract 
and which in the cord lie close to the median fissure are in the medulla 
placed to the outer side of the pyramid, being pushed aside, as it were, by 
the interpolation of the fibres derived from the crossed pyramidal tract, which INTERNAL STRUCTURE OF THE MEDULLA OBLONGATA 
947 
are much more numerous. The crossed pyramidal fibres ascend from the lat- 
eral column of the spinal cord, and, passing through the anterior gray cornu 
and across the middle line, form the inner part of the pyramid. In consequence 
of this passage of white fibres through its substance the anterior gray cornu 
is broken up into a coarse network, while one portion of it, the caput cornu, is 
entirely separated from the rest; only the base of the cornu remains intact, close 
to the ventrolateral aspect of the central canal. The caput cornu, thus separated, 
is displaced laterally, and comes to lie close to the caput cornu posterioris, which 
DORSO-MEDIAN 
FISSURE 
DORSO-M EDIAN 
FISSURE 
NUCLEUS GRACILIS 
DORSAL 
ROOTS 
DORSO-LATERAL 
COLUM N 
SENSORY 
ROOTS 
DORSAL 
HORN 
CROSSED PYRAM 
IDAL TRACT 
HEAD OF 
DORSAL 
HORN 
BASE OF 
'ventral 
HORN 
VENTRAL. 
HORN 
HEAD OF 
VENTRAL 
HORN 
VENTRAL.. 
ROOTS 
MOTOR 
ROOTS 
VENTRAL MEDIAN 
FISSURE 
VENTRO-MEDIAN 
FISSURE 
Fig. 608.-Transverse section of the oblongata at its 
lower end. (Testut.) 
Fig. 609.-Transverse section of the oblon- 
gata at the decussation of the pyramids. 
(Testut, after Duval.) 
has also shifted its position. In consequence of this breaking up of the greater 
part of the anterior gray cornu by white fibres a coarse network is formed in the 
anterior and lateral areas of the medulla, which is named the formatio reticularis 
(Fig. 607). 
fhe posterior cornu also undergoes somewhat similar changes. It becomes 
subdivided by the passage through it of the sensory fibres of the columns of Goll 
and Burdach. These pass across to the opposite anterior area of the medulla, 
where they are seen to lie immediately on the dorsal aspect of the pyramids. In 
0UNEA^S 
NUCLEUS 
GRACILIS 
DORSOMEDIAN 
HEAD OF DORSAL HORN 
LEMNISCUS- 
BASE OF VENTRAL HORN 
HEAD OF VENTRAL HORN 
Fig. 610.-Transverse section of the oblongata at the crossing of the fillets. (Testut.) 
their passage through the posterior horns of gray matter the latter become sub- 
divided, in a manner somewhat similar to what has been seen to occur in the 
anterior horns. This crossing of the sensory fibres is termed the superior pyram- 
idal or sensory decussation (Fig. 605). The caput cornu is displaced outward, so 
as almost to reach the surface, where it forms a projection, the fasciculus of Rolando, 
which enlarges above into a distinct prominence, the tubercle of Rolando (Fig. 607). 
Above the level of the tubercle of Rolando the caput cornu is separated from 948 
THE NERVOUS SYSTEM 
the surface by a band of fibres termed the ascending root of the fifth nerve (tractus 
spinalis n. trigemini) and by the external arcuate fibres (Fig. 607). The neck 
of the cornu becomes broken up into a reticular formation by the decussation of 
the columns of Goll and Burdach, and by this means the caput is separated from 
the rest of the gray matter. The base of the cornu increases in size, and, as the 
central canal expands into the fourth ventricle, becomes pushed outward, and 
portions of it extend into the fasciculus graciles and cuneati, and produce exter- 
nally the eminences of the clava and cuneate tubercle. A third portion of the 
base becomes separated from the rest, and is placed outside the nucleus of the 
fasciculus cuneatus. This is called the accessory cuneate nucleus, and is supposed 
to be a continuation upward of Clarke's vesicular column of the cord. 
The Upper Part of the Medulla (Figs. 607,611, and 612).-The upper part 
of the medulla comprises the portion which enters into the formation of the 
FLOOR OF FOURTH VENTRICLE 
NUCLEUS GRACILIS 
NUCLEUS CUNEATUS 
BASE OF VENTRAL HORN 
ROOT OF TRIFACIAL CAPPING 
HEAD OF DORSAL HORN 
VAGUS NERVE 
HEAD OF VENTRAL HORN 
■OLIVE 
HYPOGLOSSAL NERVE 
LEMNISCU* 
VENTRAL PYRAMID 
Fig. 611.-Transverse section of the oblongata at the lower end of the olives. The roof of the fourth 
ventricle is not represented. (Testut, after Duval.) 
floor of the fourth ventricle, where, in fact, the upper end of the central canal 
has opened out into this cavity. In this region the formatio reticularis is con- 
fined chiefly to the anterior and lateral areas. In the ventral portion of the pos- 
terior area there is only a small amount of reticular formation, but in addition to 
this there are individual masses of cells scattered among the longitudinal fibres. 
fvOo« OF FOURTH venthole 
HYPOGLOSSAL 
NUCLEUS 
SENSORY NUCLEUS 
NUCLEUS CUNEATUS 
HEAD OF DORSAL HORN 
ROOT OF TRIFACIAL NERVE 
MOTOR NUCLEUS OF MIXED 
NERVES 
ACCESSORY HYPOGLOSSAL 
NUCLEUS 
OLIVE 
VENTRAL 
'pyramid 
HYPOGLOSSAL NERVE 
LEM N ISCUS' 
VENTROMEDlAN 
fIssure 
ApWFORM 
NUCLEUS 
Fig. 612.-Transverse section of the oblongata at the middle of the olives. The roof of the fourth ventricle 
is not represented. (Testut, after Duval.) 
The Formatio Reticularis (Fig. 607).-The formatio reticularis is a network 
of white matter in the deep portion of the medulla, the network containing INTERNAL STRUCTURE OE THE MEDULLA OBLONGATA 
949 
gray matter. It is situated behind the pyramid and olivary body, extending 
laterally as far as the restiform bodies, and dorsally to within a short distance 
of the floor of the fourth ventricle. It presents a peculiar reticulated appear- 
ance, from which it derives its name, and which is due to the intersection of 
bundles of fibres running at right angles to each other, some being longitudinal, 
others transverse. The formatio reticularis presents a different appearance in 
the anterior area from what it does in the lateral area. In the former there is 
almost an entire absence of nerve-cells in the reticulated network, and hence it 
is known as the formatio reticularis alba; whereas, in the lateral area, the nerve- 
cells are numerous, and, as a consequence, this part is known as the formatio 
reticularis grisea. In the substance of the formatio reticularis is a small nucleus 
of gray matter. It is situated near the dorsal aspect of the hilum of the olivary 
nucleus, and has been named the inferior central nucleus. The formatio reticu- 
laris contains both longitudinal and transverse fibres. In the anterior area 
the longitudinal fibres may be arranged in two well-defined sets: (1) One set 
lies immediately behind the pyramid, and is named the interolivary fillet or 
lemniscus (lemniscus interolivaris) (Fig. 610). The fibres of the fillet are chiefly 
derived from the cells of the gracile and cuneate nuclei (Fig. 607), and may 
therefore be regarded as relay fibres of the columns of Goll and Burdach of 
the spinal cord, which terminate in synapses around the cells of the gracile and 
cuneate nuclei. They are prolonged inward and forward across the middle line 
forming the superior pyramidal or sensory decussation or the decussation of the 
fillet (Fig. 605). (2) The other set is continuous from the antero-lateral ground 
bundle of the cord, and a portion of these fibres forms the posterior longitu- 
dinal bundle (jasciculus long itudinalis medialis), already referred to (p. 908). 
Both these sets of fibres are continued upward into the pons and mid-brain. 
The longitudinal fibres of the reticular formation in the lateral area are not 
arranged in distinct bundles. They are derived from the lateral column of the 
cord, after the crossed pyramidal tract has passed over to the opposite side. 
The longitudinal fibres of the posterior area are merely indeterminate fibres of 
the formatio reticularis, with the exception of two distinct bundles, which may 
be regarded as ascending roots of the fifth nerve (Fig. 607) and vago-glcsso- 
pharyngeal nerves; the latter is termed the fasciculus solitarius (Fig. 607). 
The Transverse Fibres of the reticular formation are the arched or arcuate fibres. 
The external arciform or arcuate fibres have already been described. The internal arci- 
form or arcuate fibres (fibrae arcuatae internae) are more numerous than the super- 
ficial set; they traverse nearly the whole area of the upper half of the medulla, except 
the pyramid. They pass from the raphe; some become superficial and join the 
external arciform fibres, while others remain deep and pass to the olivary body, the 
restiform body, and to the nuclei of the fasciculus cuneatus and fasciculus gracilis. 
Independent Nuclei (Fig. 613).-In the upper part of the medulla are several 
independent nuclei of gray matter, which may be divided into two sets: (1) those 
which are traceable from the gray matter of the spinal cord, and (2) those which 
are not represented in the cord. The former are the hypoglossal nucleus, the 
nucleus of the fasciculus teres, and those of the auditory, glosso-pharyngeal, vagus, 
and spinal accessory nerves. The latter are the nucleus of the olivary body and 
the accessory olivary nuclei. In addition to these, small collections of gray matter 
are to be found in the median septum or raphe. 
The Hypoglossal Nucleus (Figs. 607, 612, and 613).-The base of the anterior 
horn, which in the lower part of the medulla was situated on the ventro-lateral 
aspect of the central canal, now approaches the floor of the ventricle, where it 
lies close to the median sulcus under the fasciculus teres. In it is a column of 
large nerve-cells, from which the roots of the hypoglossal nerve are derived. It 
is accordingly designated the hypoglossal nucleus. 950 
THE NERVOUS SYSTEM 
The Auditory Nuclei (Fig. 613).-Toward the upper part of the medulla, a con- 
siderable tract of gray matter may be found lying immediately beneath that por- 
tion of the floor of the fourth ventricle which is known as the trigonum acustici. 
This is the dorsal or inner auditory nucleus, and it lies just external to the vago- 
glosso-pharyngeal nucleus. In addition to this there is a small collection of 
nerve-cells on the ventral surface of the restiform body, between the two roots 
of the auditory nerve, which is known as the accessory or ventral auditory nucleus. 
On the outer side of the restiform body is a mass of cells associated with the 
cochlear root of the auditory nerve. This mass is termed the lateral acoustic 
tubercle or ganglion radicis cochlearis. 
Nuclei of the Glosso-pharyngeal and Vagus Nerves (Fig. 613).-These are two in 
number, principal and accessory. The principal nucleus of the two nerves lies beneath 
that portion of the floor of the fourth ventricle which is known as the ala cinerea 
INTERNAL 
GENICULATE 
BODY 
PULVI N AR 
SUPERIOR 
QUADRIGEMINAL 
BODY 
NUCLEUS 
OF THIRD 
NUCLEUS 
OF FOURTH 
INTERNAL ROOT 
OF OPTIC TRACT 
FOURTH 
DESCENDING ROOT 
AND NUCLEUS OF 
DESCENDING ROOT 
OF FIFTH 
OPTIC 
TRACT 
MOTOR ROOT 
OF FIFTH 
EXTERNAL 
GENICULATE^ 
BODY 
EXTERNAL ROOT 
OF OPTIC TRACT' 
SENSORY NUCLEUS. 
OF FIFTH 
SENSORY PORTION 
OF FIFTH 
SUPERIOR NUCLEUS' 
OF VESTIBULAR 
'GASSERIAN 
GANGLION 
SENSORY PORTION 
INNER NUCLEUS 
OF VESTIBULAR- 
MOTOR PORTION 
EMERGING PORTION 
INNER PORTION 
FIFTH 
ROOT OF 
SEVENTH 
VENTRAL NUCLEUS 
OF COCH LEAR 
OUTER NUCLEUS 
OF VESTI BULAR' 
NUCLEUS OF SIXTH 
PARS PRIMA RADICIS 
N. FACIALIS 
COCH LEAR 
ROOT 
■NUCLEUS 
OF SEVENTH 
SEVENTH 
VESTIBULAR 
ROOT 
NINTH- 
ELEVENTH 
-TENTH 
NINTH 
TENTH 
DORSAL NUCLEUS 
OF COCHLEAR 
MOTOR NUCLEI OF 
NINTH AND TENTH 
NUCLEUS OF 
TWELFTH 
SPINAL ROOT 
OF FIFTH 
SPINAL NUCLEUS 
OF VESTIBULAR 
NUCLEUS OF ALA 
CIN EREA AND 
TRACTUS SOLITARIUS 
NUCLEUS OF 
ELEVENTH 
COMMISSURAL GANGLION 
OF ALA CINEREA 
Fig. 613.-The nuclei of the origin of the motor and primary terminal nuclei of sensory cerebral nerves, 
schematically represented in a supposedly transparent brain stem, viewed from behind. Nuclei and roots of 
motor nerves, red; of sensory, reddish-violet; of the cochlear nerve, yellow; and of the optic nerve, bluish-violet. 
X 2. (Held.) 
and fovea inferior. They form an oblong mass of gray matter, above the nucleus 
of the spinal accessory and lateral to the hypoglossal nucleus. The accessory nuclei 
are situated in the reticular formation of the posterior area, some distance from 
the floor of the fourth ventricle. They consist of a pear-shaped mass of cells, 
which is connected with the rest of the gray matter by a sort of stalk or peduncle, 
and was formerly known as the nucleus ambiguus (Fig. 607). 
Nucleus of the Spinal Accessory Nerve (Fig. 613).-This nucleus consists of a 
group of cells, which is situated partly in the lower part of the medulla at the 
base of the posterior horn and close to the central canal. It extends upward, INTERNAL STRUCTURE OF THE MEDULLA OBLONGATA 
951 
lying beneath the lower part of the floor of the fourth ventricle and on the outer 
side of the hypoglossal nucleus. 
The Nucleus of the Olivary Body (nucleus olivaris inferior) (Fig. 607).-When 
the olivary body is cut across, it is seen to be covered externally by white fibres, 
and internally to consist of a gray layer. The fibres which invest the nucleus are 
derived from the antero-lateral ground bundle. The gray layer is the nucleus of 
the olivary body, or, as it is sometimes called, the corpus dentatum of the olive. It is 
composed of a thin, wavy lamina, which is arranged in the form of a hollow capsule, 
open at its upper and inner part, and presenting a zigzag or dentated outline. 
Microscopically examined, the olivary nucleus is seen to consist of small, rounded, 
yellowish nerve-cells embedded in a matrix of neuroglia and fine nerve-fibres. 
White fibres, which can be traced from the raph£, and are probably derived 
from the opposite olive, enter the interior of the capsule by the aperture at its upper 
or inner part, these fibres constituting the olivary peduncle. The olivary peduncle 
is the lower portion of the cerebello-olivary tract (fibrae cerebelloolivares). This 
tract connects the cerebellar hemisphere with the opposite olivary nucleus. 
The fibres of the olivary peduncle as they enter the olivary body diverge and 
some are lost in the gray matter of the olivary nucleus; others pass through it, and 
of these some turn backward to join the restiform body, and pass to the cerebellum 
as internal arcuate fibres; while others pierce the white matter of the olivary body 
and, reaching the surface, are continued to the restiform body as external arcuate 
fibres. The nucleus receives the olivary bundle of the spinal cord, the group of 
fibres called the triangular tract of Helwig. The central tegmental tract arises 
in the olivary nucleus and passes to the lenticular nucleus. The olivary 
nucleus receives another descending tract besides the cerebello-olivary, namely, 
the vestibulo-olivary (Santee). From the nucleus fibres pass by way of the lateral 
column to the anterior cornu of the same side of the spinal cord. Removal of 
one cerebellar hemisphere is followed by atrophy of the opposite olivary nucleus. 
Accessory Olivary Nuclei (Fig. 607).-Two small isolated masses of gray matter 
are to be found, one on the mesial and the other on the dorsal aspect of the corpus 
dentatum. These are the medial or internal accessory olivary nucleus (nucleus 
olivaris accessorius medialis) and the external or lateral accessory olivary nucleus 
(nucleus olivaris accessorius dorsalis). They are connected with the restiform 
body by some of the internal arcuate fibres. The fibres of the hypoglossal 
nerve, as they traverse the bulb, pass between the medial accessory nucleus and 
the chief olivary nucleus. 
The Raphe (Fig. 607).-The raph£ is situated in the middle line of the medulla, 
above the decussation of the pyramids. It consists of nerve-fibres intermingled 
with nerve-cells. The fibres have different directions, which can only be seen in 
suitable microscopic sections, thus: 1. Some are antero-posterior; these in front 
are continuous with the superficial arciform fibres. 2. Some are longitudinal; 
these are derived from the arciform fibres, which on entering the raphe change 
their direction and become longitudinal. 3. Some are oblique; these are continu- 
ous with the deep arciform fibres which pass from the raphe. 
The nerve-cells of the raphe are multipolar; some are connected with the 
antero-posterior fibres, others with the superficial arcuate fibres. 
Weight of the Encephalon.-The average weight of the brain in the adult male 
is 49| oz., or a little more than 3 lbs. avoirdupois; that of the female 44 oz.; the 
average difference between the two being from 5 to 6 oz. The prevailing weight 
of the brain in the male ranges between 46 oz. and 53 oz., and in the female 
between 41 oz. and 47 oz. In the male the maximum weight out of 278 cases was 
65 oz., and the minimum weight 34 oz. The maximum weight of the adult female 
brain out of 191 cases was 56 oz., and the minimum weight 31 oz. According to 
Luschka, the average weight of a man's brain is 1424 grammes (about 45 oz.), THE NERVOUS SYSTEM 
952 
of a woman's 1272 grammes (about 41 oz.), and, according to Krause, 1570 
grammes (about 48| oz.) for the male and 1350 (about 43 oz.) for the female. It 
appears that the weight of the brain increases rapidly up to the seventh year, more 
slowly to between sixteen and twenty, and still more slowly to between thirty and 
forty, when it reaches its maximum. Beyond this period, as age advances and the 
mental faculties decline, the brain diminishes slowly in weight, about an ounce 
for each subsequent decennial period. These results apply alike to both sexes. 
Marshall concluded that if woman is judged by her height only, she has a smaller 
amount of cerebral matter than has man; if she is judged by her weight alone, she 
has more; but if both sexes are gauged by both standards, their "cerebral endow- 
ment is seen to be practically equal.''1 
The size of the brain was formerly said to bear a general relation to the intel- 
lectual capacity of the individual. Cuvier's brain weighed rather more than 64 
oz., that of Daniel Webster 63| oz., that of Dr. Abercrombie 63 oz. On the 
other hand, the brain of an idiot seldom weighs more than 23 oz. But these 
facts are by no means conclusive, and it is well known that these weights have been 
equalled by the brains of persons who never displayed any remarkable intellect. 
Dr. Haldennan, of Cincinnati, has recorded the case of a mulatto, aged forty-five, 
whose brain weighed 6S| oz.; he had been a slave, and was never regarded as 
particularly intelligent; he was illiterate, but is said to have been reserved, medi- 
tative, and economical. Dr. James Morris recorded the case of a bricklayer, who 
could not read or write, whose brain weighed 67 oz. Dr. Ensor, district medical 
officer at Port Elizabeth, reports that the brain of Carey, the Irish informer, 
weighed 61 oz. In not a few instances the brains of very able men have been of 
average weight or of less than average weight. The brain of Samuel I). Gross, 
the surgeon, weighed 48 oz., the brain of Gambetta, the statesman, 40^ oz., the 
brain of Walt Whitman, the poet, 43.3 oz., the brain of Hughes Bennett, the 
physician, 47 oz., the brain of Joseph Leidy, the naturalist and anatomist, 49.9 oz., 
and the brain of Dollinger, the physiologist, 42.6 oz. M. Nikiforoff has published 
an article in the Novosti on the subject of the weight of brains. According to 
him, the weight of the brain has no influence whatever on the mental faculties. 
It ought to be remembered that the significance of the weight of the brain should 
depend upon the proportion it bears to the dimensions of the whole body and to 
the age of the individual. There seems to be a relation between the weight of the 
brain and the body weight and stature. Quain gives the ratio between the 
brain weight and body weight as 1 to 41 in healthy individuals, but this propor- 
tion is by no means fixed and seems to vary widely in either direction. As the 
stature increases the brain weight increases, but, as Mills says,2 "taller persons 
have relatively less brain matter than shorter ones, although absolutely they have 
more." The significance of the weight of the brain also depends upon the cause 
of death, for long illness or old age wastes the brain. To define the real 
degree of development of the brain, it is therefore necessary to have a knowl- 
edge of the condition of the whole body, and, as this is usually lacking, the mere 
record of weight possesses little significance. As Mills says:3 "Apparently there 
is no invariable nor necessary relation between mere brain weight and the 
degree of individual intelligence; but high brain weights occur in larger propor- 
tions among civilized than among uncivilized races." Furthermore, it is to be 
remembered that a heavy brain may be a diseased brain. For instance, Byron's 
brain weighed nearly 64 oz. and showed evidences of disease. 
'The human brain is heavier than the brain of any of the lower animals, except- 
ing the elephant and whale. The brain of the former weighs from eight to ten 
pounds; and that of a whale, in a specimen seventy-five feet long, weighed rather 
more than five pounds. 
The Nervous System and its Diseases, By Prof. Charles K. Mills. 2 Ibid. 3 Ibid. CEREBRAL LOCALIZATION AND TOPOGRAPHY 
953 
CEREBRAL LOCALIZATION AND TOPOGRAPHY. 
The cortex of the brain is highly specialized, and different regions represent special functions. 
In it are represented "the numerous manifestations associated with consciousness;" in it mem- 
ories are stored up; and "in it occur the last and highest bodily processes concerned with sensa- 
tions received from without, and with the setting free of impulses which are projected to lower 
centres and to the outside world."1 A centre is an aggregation of nerve-cells and fibres, which 
"aggregation represents physiologically some action" (Mills). Physiological and pathological 
researches and surgical operations have proved that the surface of the brain may be mapped out 
into series of definite centres, each one of which is intimately connected with some well-defined 
function. A group of centres is known as a zone, an area, or a region. As Hughlings Jackson 
says, the study of centres is an investigation into the anatomical "substrata" of visual, motor, 
tactile, and other ideas; of "the parts which represent impressions of sight, of touch, of move- 
ment, and other functions" (Mills). Certain cortical centres are known as motor centres. Stimu- 
lation of these centres causes movement. Destruction of these centres renders movement impos- 
Fig. 614.-Drawing to illustrate cranio-cerebral topography. (Taken from a cast in the Museum of the Royal 
College of Surgeons of England, prepared by Professor Cunningham.) 
sible. The centres are associated with contraction of muscular groups producing special move- 
ments not with the contraction of individual muscles. They represent movements rather than 
muscles. These centres are found particularly around the fissure of Rolando and on the mesial 
surface of the hemisphere, and they are associated with movements of the extremities of the 
opposite side of the body, and movements of the face, mouth, and tongue. Mills, von Monakow, 
and Sherrington are of the opinion that the motor areas are entirely in front of the fissure of 
Rolando (Figs. 615 and 616). This view is highly probable, but is not absolutely proved. Other 
observers hold that the motor areas occupy the entire ascending frontal and ascending parietal con- 
volutions, extend a little way forward into the third frontal convolution and backward into the 
superior parietal convolution. The motor areas certainly extend on to the mesial surface in the 
paracentral lobule and pass perhaps into the marginal convolution. On the convexity of the hemi- 
1 The Nervous System and its Diseases. By Prof. Charles K. Mills. 954 
THE NERVOUS SYSTEM 
sphere the highest centre is the leg area. Below this, in the order named, are the centres for the arm, 
face, lips, tongue, larynx, and pharynx. On the mesial surface from before backward are areas for 
the head, shoulder, trunk, hip, knee, leg, and foot. The centres for head and eye movements are 
in front of the arm centre. In a large motor area there are certain smaller areas. For instance, 
the area for the lower extremity contains separate centres, representing movements of the hip, 
knee, leg, foot, and toes. 
The arm centre contains centres for movements of the shoulder, arm, wrist, thumb, and 
fingers. The face centre contains centres for movements of the upper face, the lower face, the 
CONCRETE CONCEPT 
Fig. 615.-Side view of human brain, showing localization of functions. (Charles K. Mills.) 
lips, and tongue. The somoesthetic area or the area of general sensation is not certainly marked 
out. Those who believe that the motor area is both front and back of the Rolandic fissure 
maintain that the area of general sensation largely corresponds to the motor area, but is of 
greater extent as it enters into the limbic lobe. Mills places it back of the fissure of Rolando 
in the convexity and also on the mesial surface of the hemisphere. 
Fig. 616.-View of the mesial surface of human brain, showing localization of functions. (Charles K. Mills.) 
The cortical centres are shown in Figs. 617 and 618. This is not the place, nor can space 
be given, to describe these localities. 
Cranio-cerebral Topography.-The position of the principal fissures and convolutions of the 
cerebrum and their relation to the outer surface of the scalp (Fig. 614) have been the subject of CEREBRAL LOCALIZATION AND TOPOGRAPHY 
955 
much investigation, and many systems have been devised by which one may localize these parts 
from an explanation of the external surface of the head. 
These plans can only be regarded as approximately correct for several reasons; in the first 
place, because the relations of the convolutions and sulci to the surface are found to be very 
variable in different individuals; secondly, because the surface area of the scalp is greater than 
the surface area of the brain, so that lines drawn on the one cannot correspond exactly to sulci 
or convolutions on the other; and thirdly, because the sulci and convolutions in two individuals 
are never precisely alike. Nevertheless, the principal fissures and convolutions can be mapped 
out with sufficient accuracy for all practical purposes, so that any particular convolution can be 
generally exposed by removing with the trephine a certain portion of the skull's area. 
Fig. 617.-The localization of various centres on the outer surface of the left side of the human brain. 
(American Text-book of Surgery.) 
The various landmarks on the outside of the skull, which can be easily felt, and which serve 
as indications of the position of the parts beneath, have been already referred to (see page 149), 
and the relation of the fissures and convolutions to these landmarks is as follows: 
Longitudinal Fissure (Fig. 619).-This corresponds to a line drawn from the glabella at 
the root of the nose to the external occipital protuberance. 
The Fissure of Sylvius (Fig. 619).-The position of the fissure of Sylvius and its posterior 
horizontal limb is marked by a line starting from a point one inch and a quarter horizontally 
behind the external angular process of the frontal bone to a point three-quarters of an inch below 
Fig. 618.-The localization of various centres on the median surface of the human brain. 
(American Text-book of Surgery.) 
the most prominent point of the parietal eminence. The first three-quarters of an inch will rep- 
resent the main fissure, the remainder the horizontal limb. The bifurcation of the fissure is 
therefore two inches behind and about a quarter of an inch' above the level of the external angu- 
lar process. The ascending limb of the fissure passes upward from this point parallel to, and 
immediately behind, the coronal suture. 
The Transverse Fissure or Fissure of Eichat.-This is between the cerebrum and cerebellum 
and corresponds to a line drawn from the inion to the external auditorv meatus (the line B C in 
Fig. 619). 956 
THE NERVOUS SYSTEM 
Fissure of Rolando.-To find the upper end of the fissure of Rolando, a measurement should 
be taken from the glabella to the external occipital protuberance. The position of the top 
of the sulcus will be, measuring from in front, 55.6 per cent, of the whole distance from the 
glabella to the external occipital protuberance. Professor Thane adopts a somewhat simpler 
method. He divides the distance from the glabella to the external occipital protuberance over 
the top of the head into two equal parts, and, having thus defined the middle point of the vertex, 
he takes half an inch behind it as the top of the sulcus. This is not quite so accurate as the 
former method, but it is sufficiently so for all practical purposes, and on account of its simplicity 
is very generally adopted. From this point the fissure runs downward and forward for 3| inches, 
its axis making an angle of 67° with the middle line. Cunningham states that this angle more 
nearly averages 71.5°. In order to mark this groove, two strips of metal may be employed- 
one, the shorter, being fixed to the middle of the other at the angle mentioned. If the longer 
strip is now placed along the sagittal suture so that the junction of the two strips is over the 
point corresponding to the top of the furrow, the shorter, oblique strip will indicate the direction 
and 3| inches will mark the length of the furrow. Dr. Wilson has devised an instrument, called 
a cyrtometer, which combines the scale of measurements for localizing the fissure with data for 
representing its length and direction.1 Professor Thane gives the lower end of the furrow as 
Fig. 619.-Relations of the principal fissures and convolutions of the cerebrum to the outer surface of the 
scalp. (Reid.) 
"close to the posterior limb, and about half an inch behind the bifurcation of the fissure of 
Sylvius.'' So that, according to this anatomist, a line drawn from a point half an inch behind 
the mid-point between the glabella and external occipital protuberance to this spot would mark 
out the fissure of Rolando. Dr. Reid adopts a different method (Fig. 619). He first indicates 
on the surface the longitudinal fissure and the horizontal limb of the fissure of Sylvius (as above). 
He then draws two perpendicular lines from his "base-line" (that is, a line from the lowest 
part of the infraorbital margin through the middle of the external auditory meatus to the back 
of the head) to the top of the cranium, one (D E, Fig. 619) from the depression in front of the 
external auditory meatus, and the other ( F G, Fig. 619) from the posterior border of the mastoid 
process at its root. He has thus described on the surface of the head a four-sided figure (F D G E, 
Fig. 619), and a diagonal line from the posterior superior angle to the anterior perpendicular 
line where it is crossed by the fissure of Sylvius will represent the furrow. 
The Parieto-OCCipital Fissure on the upper surface of the cerebrum runs outward at right 
angles to the great longitudinal fissure for about an inch, from a point one-fifth of an inch in 
front of the lambda (posterior fontanelle). Reid states that if the horizontal limb of the fissure 
of Sylvius be continued onward to the sagittal suture, the last inch of this line will indicate the 
position of the sulcus (Fig. 619). 
' Lancet, 1888, vol. i, p. 408. CEREBRAL LOCALIZATION AND TOPOGRAPHY 
957 
The Pre-central Sulcus begins four-fifths of an inch in front of the middle of the fissure of 
Rolando, and extends nearly, but not quite, to the horizontal limb of the fissure of Sylvius. 
The Superior Frontal Fissure runs backward from the supraorbital notch, parallel with the 
line of the longitudinal fissure to two-fifths of an inch in front of the line indicating the position 
of the fissure of Rolando. 
'rhe Inferior Frontal Fissure follows the course of the superior temporal ridge on the frontal 
bone. 
The Intraparietal Fissure begins on a level with the junction of the middle and lower third 
of the fissure of Rolando, on a line carried across the head from the back of the root of one 
auricle to that of the other. After passing upward it curves backward, lying parallel to the 
longitudinal fissure, midway between it and the parietal eminence; it then curves downward to 
end midway between the posterior fontanelle and the parietal eminence. 
Supra orbital Une 
(Superior Horizontal) 
Orbital-auricular line 
(Base line) 
Fig. 620.-Kronlein's method for determining the portions of certain fissures of the brain. 
Kronlein's method for determining the portions of certain fissures of the brain is very useful and 
easy of application (Fig. 620). It is as follows: (1) The base line, Z M, is a horizontal line run- 
ning at the level of the lower border of the orbit and the upper border of the external auditory 
meatus. (2) Another horizontal line, K K', is drawn parallel to Z M. The second horizontal line 
is on a level with the supraorbital ridge. (3) A vertical line, Z K, is erected from Z M at the 
middle of the zygoma and is carried to the line, K K'. (4) Another vertical line, A R, is erected 
from the base-line at the level of the articulation of the mandible and is carried to R. (5) A third 
vertical line, M P, is erected from the base-line at the posterior border of the mastoid process 
and is carried to the middle line of the skull, which is marked P. (6) A line is drawn from 958 
THE NERVOUS SYSTEM 
K to P. The portion of this line between R and P' corresponds to the fissure of Rolando. (7) 
The angle P K K is bisected by the line K S. K S corresponds to the fissure of Sylvius from 
its bifurcation to its termination posteriorly, and K is directly over the bifurcation. To reach 
the anterior branch of the middle meningeal, apply the trephine at K; to reach the posterior 
branch, apply it at K'. In abscess of the temporo-sphenoidal lobe the trephine should be applied, 
according to von Bergmann, in the region A a K' J/. 
THE NERVE-PATHS. 
The anatomy of the various parts of the central nervous system having been 
described, a short account will now be given of the course taken by its more impor- 
tant nerve-paths, and of the direction in which impulses pass along them. Before 
doing so, however, it is necessary to refer to the methods employed in elucidating 
this complex subject. All nerve-fibres may be regarded as outgrowths from nerve- 
cells, and it is found that if a nerve-fibre be cut, the portion of it which is severed 
from the cell undergoes degeneration and becomes atrophied. Until recent years 
it was believed that the cell itself showed no change under such circumstances. 
This, however, is not the case, for if a nerve, the sciatic, for instance, be divided in 
an animal, and after an interval of some weeks the animal be injected with methy- 
lene blue and killed, it will be seen, on examining sections of the lumbar region 
of the spinal cord, that the cells are stained imperfectly or not at all, owing to a 
diminution, or, it may be, an entire disappearance of the chromatin, a substance 
which, in a normal cell, shows marked affinity for staining reagents. Fuither, the 
body of the cell is swollen, the nucleus displayed toward the periphery, and the 
part of the axone still attached to the altered cell is diminished in size and some- 
what atrophied. Under favorable conditions the cell is capable of reassuming its 
normal appearance and the axone may commence to grow. This method of study by 
injection of methylene blue is of great value in determining the origin of nerve-fibres 
from their cells. Again, electrical stimulation of certain localized areas of the brain 
or of the tracts arising from them is followed by the contraction of the muscles of 
the body. The cortical centres of the motor tracts are situated in the convolutions 
adjacent to the fissure of Rolando (page 953). When the stimulus is applied to one 
part of the motor area the muscles of one limb of the opposite contract, while other 
portions control the movements of the other limb of the opposite side, etc. Destruc- 
tion of these parts entails loss of function, paralysis of muscles, and degeneration 
of the tracts below the seat of injury. During life injury and disease may give 
rise to symptoms resembling either the effects of stimulation or those of destruc- 
tion; and after death the tracts, or the centres of the tracts, are seen to be 
degenerated or otherwise altered. It was long believed by all and is still main- 
tained by many that the motor area includes the ascending parietal, ascending 
frontal, and superior parietal convolutions. Mills, von Monakow, Sherrington and 
other high authorities now teach that the motor region is entirely in front of the 
central fissure, with the possible exception that the gyral mass between the foot 
of the fissure of Rolando and the Sylvian fissure, and extending a little back of the 
line of the central fissure, which may be included in the area for the face (Charles 
K. Mills) (Figs. 615 and 616). The motor areas are separated from each other 
and do not overlap, but probably interdigitate (Mills). The same is true of the 
areas for cutaneous sensibility. By observing the development of the nervous sys- 
tem during the growth of the embryo, the fact is disclosed that all axis-cylinders 
do not acquire a medullary sheath at one and the same time. Speaking generally, 
it may be said that afferent fibres become medullated before efferent, and that in 
the case of the latter myelination occurs earlier in the brain than in the cord. 
By watching the effects of these different processes the functions of a considerable 
part of the brain and of the nerves leading from or to it have been determined. THE HER VE- PA THS 
959 
The Motor, Efferent, or Descending Tract (Figs. 621, 622, and 623).-The 
constituent fibres of this tract are the axis-cylinder processes of cells situated 
in the cortex of the convolutions about and probably solely in front of the 
fissure of Rolando. At first they are somewhat widely diffused, but as they 
Fig. 621.-Scheme of the motor pathway; c, 
centra], p, peripheral, neurone; d, decussation: in, 
muscle. (Jakob.) 
Fig. 622.-Scheme showing the course of the 
pyramidal tract. 1, in the cerebrum and crus; II, 
in the pons; III, in the medulla oblongata; IV, de- 
cussation of the pyramids; F, in the cervical en- 
largement; FZ, in the lumbar enlargement. (Jakob.) 
descend through the corona radiata they gradually approach each other and 
pass between the lenticular nucleus and optic thalamus in the genu and 
anterior two-thirds of the posterior limb of the internal capsule. Proceeding 
downward they next occupy the middle three-fifths of the pes or crusta of the 
crus cerebri, and enter the pons Varolii, where the 
transverse fibres of this body not only conceal them, 
but divide them up into irregular bundles. Eventu- 
ally they reach the medulla, and here the motor 
tracts form the anterior pyramids which lie one on 
each side of the median fissure. The tiansit of the 
fibres from the medulla is effected by two paths. 
The fibres nearest to the anterior median fissure 
cross the middle line, forming the decussation of 
the pyramids (Figs. 594, 6C5, 609, 621, 622, and 623), 
and descend in the opposite side of the cord as the 
indirect or crossed pyramidal tract (Figs. 605 and 623). 
Throughout the length of the spinal cord fibres 
from this column pass into the gray matter, to ter- 
minate by ramifying around the cells of the ante- 
rior horn. The more laterally placed poition of the 
motor tract does not decussate in the medulla, but 
descends as the direct or uncrossed pyramidal tract 
(Fig. 605); these fibres, however, end in the anterior 
gray horn of the opposite side of the spinal cord by 
passing across in the anterior white commissure. 1. Motor and inhibiting influ- 
ences which reach the spinal nerves arise in the upper three-fourths of the motor 
area in front of the Rolandic fissure, pass along the fibres of the corona radiata 
Fig. 623.-Scheme showing the 
posit ion of t he pyramidal t ract. Py, 
in the mesencephalon; III, F, VII, 
XII, central motor pathways to 
the corresponding cranial nerves. 
(Jakob.) 960 
THE NERVOUS SYSTEM 
and of the anterior twc-thirds of the posterior limb of the internal capsule, the 
middle three-fifths of the crusta, the anterior or ventral pontine fibres, and the 
medullary pyramids. From this point they may pass along either the crossed or the 
uncrossed pyramidal tract to reach the gray horn of the opposite side of the spinal 
cord. " By the former route the impulses cross over in the medulla, through the 
decussation of the pyramids, and descend in the lateral column of the spinal cord; 
but by the uncrossed route they descend in the anterior column of the cord and 
decussate in succession through the white commissure. Impulses by either route 
finally reach the anterior gray cornu of the spinal cord, and, with the exception of a 
small percentage of them, they reach the cornu opposite to their Rolandic origin. 
The few undecussated fibres in the crossed pyramidal tract conduct uncrossed 
impulses to the anterior cornu of the same side."1 2. Motor and inhibiting influ- 
ences which reach the cranial nerves arise in the lower portion of the motor 
area, pass through the corona radiata and posterior two-thirds of the internal 
capsule, but deviate from the pyramidal tract before reaching the medulla, and 
pass to the nuclei of cranial nerves (Fig. 623). On the same side fibres pass to 
the nuclei of the fourth nerve, but the balance of the fibres cross and pass to 
nuclei on the opposite side-viz., the nuclei of the third, fifth, sixth, seventh, 
ninth, tenth, eleventh, and twelfth cranial nerves. 
The Cerebro-cortico-pontal Paths.-These paths pass through the cerebellum. 
Impulses from the prefrontal region pass along the corona radiata, through the 
anterior limb of the internal capsule and the inner portion of the crusta. Impulses 
from the temporal region pass along the corona radiata, through the poste- 
rior limb of the internal capsule and the outer portion of the crusta. The nucleus 
pontis and cranial nerve nuclei of the same side receive the impulses from both the 
frontal and the temporal paths, and from these depots the impulses are sent to 
cranial nerves or to spinal nerves. To cranial nerves they are sent direct from 
the synapses about the nuclei. In order to reach spinal nerves they pass to the 
cerebellar cortex by means of the middle peduncle of the cerebellum. From the 
cerebellar cortex the impulses pass through the inferior peduncles of the cerebellum 
and the lateral region of the medulla to reach the anterior gray horn (by way of 
the antero-lateral descending cerebellar tract). 
The Intermediate Crusta Path (by Way of the Intermediate Bundle).-Some 
impulses which arise in the cerebral cortex pass to the corpus striatum, then to the 
nucleus pontis of the same side (chiefly), then byway of the middle peduncle of 
the cerebellum to the cerebellar cortex, and then along the antero-lateral descend- 
ing cerebellar tract. 
The Red Nucleus Path.-Impulses from the cerebral cortex may reach the red 
nucleus by way of the optic thalamus (direct route) and by way of the corpus 
striatum (indirect route). 
Impulses which reach the red nucleus by the direct route travel along the 
crossed descending tract of the red nucleus to the centre of the gray matter in the 
crescent of the opposite side of the cord. Impulses which reach the red nucleus 
by the indirect route pass to the cerebellar cortex of the opposite side and from 
the cortex along the descending cerebellar tract. 
Short Fibre Paths (chiefly in the formatio reticularis).-Santee presents a concise 
explanation of the course of impulses along these paths.2 He describes five paths: 
1. Impulses having reached the ganglia of the cerebrum and mesencephalon, 
pass along the formatio reticularis and reach the antero-lateral ground bundle 
of the spinal cord to ultimately reach the spinal nerves. Impulses leaving the 
formatio reticularis may reach motor cranial nerve nuclei. 2. Impulses may 
pass from the formatio in the pons and by way of the middle cerebellar peduncle 
1 Anatomy of the Brain and Spinal Cord. By Harris E. Santee. 2 Ibid. THE NERVE-PATHS 
961 
reach the cerebellar cortex. 3. Impulses which reach the cerebellar cortex may 
reach the antero-lateral ground bundle of the opposite side of the cord. 4. From 
the third cranial nerve nucleus fibres pass to the seventh nerve, and impulses come 
from the third nerve and are sent to the Occipito-fontalis, Corrugator supercilii, and 
Orbicularis palpebrarum muscles. 5. Fibres pass from the nucleus of the sixth 
cranial nerve to the nucleus of the opposite third nerve, and impulses pass from 
the nucleus of the sixth nerve of one side to the Internal rectus muscle of the 
opposite side. 
The Sensory, Afferent, or Ascending Tract (Figs. 624, 625, and 626). Path 
by the Columns of Goll and Burdach.-The course taken by those fibres of the 
posterior nerve-roots which ascend has been 
arrived at by dividing the nerve-roots between 
their ganglia and their entrance into the 
spinal cord and subsequently examining the 
degenerated areas. It has been found that 
the fibres pursue an oblique course, being 
situated at first in the outer part of Bur- 
dach's column; higher up they occupy the 
Fig. 624.-Scheme of the sensory pathway: c, central, p, peripheral, neurone; g, intervertebral ganglion 
cell; b, short, I, long, tract; d, decussation. (Jakob.) 
Fig. 625.-Scheme showing the course of the sensory pathway: I, in the cerebrum and cerebral pedun- 
cles; II, pons and cerebellum; III, medulla oblongata; IV, upper portion of cervical cord; V, middle portion of 
cervical cord; VI, lumbar cord; a, fibres from the antero-lateral columns and fillet; b, fibres in the posterior 
columns; c, fibres from the cerebellum and lateral columns. (Jakob.) 
Fig. 626.-Scheme of the sensory pathway. Peripheral, neurone (dotted line): 1, 2, 3, short, 4, long, tracts. 
The " switching stations " are indicated by smaller circles. Central neurone (broken line): I, columns of Clarke 
(direct cerebellar tract); II, interrupted. III. long, antero-lateral tracts; H, nuclei of posterior column (f. gra- 
cilis and f. cuneatus); SIV, decussatio lemnisci. (Jakob.) 
middle of this column, being displaced inward by the accession of other entering 
fibres, while still higher they enter and are continued upward in the column of 
Goll. The upper cervical fibres do not reach the column of Goll, but are 
entirely confined to that of Burdach. The degeneration method proves that the 
localization of these fibres is very precise: the sacral nerves lying to the inner 
side of Goll's column and near its periphery; the lumbar nerves to their outer 
side; the dorsal nerves still more laterally; while the cervical nerves are con- 
fined to the outer part of Burdach's column. 962 
THE NERVOUS SYSTEM 
On reaching the medulla these ascending fibres end by arborizing around the 
cells in the gracile and cuneate nuclei, and the further upward course of the tract 
is effected by the axis-cylinder processes of these cells. There are two paths from 
this region, the direct and the indirect. The fibres of the direct path decussate in 
the medulla, dorsal to the crossing of the motor tract, in what is termed the superior 
pyramidal decussation, the sensory decussation, or the decussation of the fillet (Figs. 605, 
610, 624, and 626), terms which are synonymous. Having crossed the middle line 
they ascend through the pons and tegmentum of the crus cerebri, and, reaching the 
ventral surface of the optic thalamus, from which they pass by the three systems of 
Flechsig to the cortex. The impulses ascending from the optic thalamus pass to the 
cortex through the internal capsule and corona radiata. Impulses which take the indi- 
rect path leave the medulla, pass to the cortex of the superior worm of the cerebellum, 
A 
B 
I. Dorsal 
TL Lumbar 
III. Lumbar 
V. Lumbar 
V. Sacral 
II. Lumbar 
IV. Sacral 
III. Lumbar 
J. Sacral 
V. Lumbar 
III. Lumbar 
V. Lumbar 
I. Sacral 
Fig. 627.-Cutaneous areas corresponding to the sensory segments of the spinal cord. A, anterior surface. 
B, posterior surface. (After Sticker.) 
and then through the superior peduncle to the optic thalamus and the red nucleus 
of the opposite side. These fibres also reach the cortex by means of the systems 
of Flechsig. The fibres of the sensory path are arranged as follows in the internal 
capsule: those which go to the fronto-parietal cortex being situated in the extreme 
front part of the anterior limb of the internal capsule, while in the hinder extremity 
of the posterior limb other fibres pass to their distribution in the temporal and 
occipital cortex. 
Path of Cranial Nerves and Medial Fillet.-Common sensory impulses passing 
along the fifth, the vestibular portion of the eighth, the ninth, and the tenth 
nerves are conveyed by the medial fillet to the ventral portion of the opposite 
optic thalamus, and from this region they are taken to the cortex by the systems 
of Flechsig. THE NERVE-PATHS 
963 
Paths by the Direct Cerebellar Tract.-The direct cerebellar tract begins about 
the level of the second lumbar vertebra, and is the continuation upward of the 
axis-cylinders of Clarke's column. At the upper end of the cord it passes into the 
restiform body and through this reaches the cortex of the superior vermis of 
the cerebellum. This tract seems to lose some of its fibres in the cord, since the 
area of degeneration resulting from a section of the lower part of the cord dimin- 
ishes from below upward; only some of its fibres therefore pass directly to the 
cerebellum. On the other hand, the tract is reinforced by an accession of fibres 
from the cord itself, so that its transverse area is greater above than below. Im- 
pulses of equilibrium pass from the posterior roots of the spinal nerves and 
ascend along the direct cerebellar tract, chiefly to the cerebellar cortex of the same 
side, partly to the cerebellar cortex of the opposite side. From the cerebellar 
cortex they pass to the cerebral cortex by the route previously referred to. 
The Path by the Antero-lateral Ascending Cerebellar Tract.-Ordinary sensory and 
thermic impulses ascend along this tract to the cerebellar cortex of the opposite 
side (the superior worm) and partly to the optic thalamus and parietal cortex. 
Short Fibre Paths.-According to Santee there are three of these paths: 1. One 
path is in the antero-lateral ground bundle and formatio reticularis. It conveys 
sensory impressions from the gray matter of the cord or from pontine and medul- 
lary nuclei which receive fibres of common sensation from cranial nerves to the 
opposite optic thalamus. 2. Another path takes impulses from the formatio 
reticularis to the cerebellar cortex and then to the red nucleus and optic thalamus. 
3. Impulses may leave the antero-lateral ascending cerebellar tract along fibres 
which diverge in the medulla. These impulses reach the lateral nucleus, pass to 
the cerebellar cortex, and finally attain the cerebral cortex.1 
Paths of Special Sensations.-(See the section on Cranial Nerves.) 
Reflex Paths.-Reflex paths are almost infinite in number and only a few can 
be set forth. A spinal reflex action is produced as follows: A stimulus im- 
parted to a sensory nerve ending is conveyed up the nerve to a centre or several 
centres in the spinal gray matter, from which it is transferred to a motor nerve, 
and by this to a muscle which responds to the stimulus by movement. Such a 
path is called a reflex arc. 
Spinal Reflexes (Fig. 628) may be very simple or somewhat complicated. In 
the simple spinal reflex the cause of the stimulus is as indicated above. Among 
these simple spinal reflexes are the patellar reflex, the reflex withdrawal of a part 
when irritated, and the skin reflexes. 
In a more complicated spinal reflex the "impulses traverse at least three neu- 
rones" (Santee). The more complicated reflexes are those of "defecation, mic- 
turition, parturition, vasomotor reflexes, cardio-accelerator reflexes, etc." (Santee). 
A Cranial Reflex travels up a sensory cranial nerve and is transferred to a motor 
cranial nerve. Among these impulses are "watering" of the mouth on smelling a 
savory dish, the facial muscular contraction due to pain in the fifth nerve, cough- 
ing, sneezing, vomiting, and swallowing. 
Spinal Cranial Reflexes are due to the ascent of impulses in the cord by way of 
the posterior longitudinal bundle or by Burdach's column, which impulses reach 
the nuclei of cranial motor nerves. "Thus is brought about the movement of the 
eyes toward the source of impulse, a change of facial expression to agree with 
the painful or pleasing character of the impulses, etc."2 Cranial spinal reflexes 
are produced by impulses from cranial sensory nerves being transferred to spinal 
motor fibres. An example of one of these reflexes is the starting on hearing a 
sudden loud sound. Among these numerous reflexes are the respiratory, auditory, 
and pupillary. 
Anatomy of the Brain and Spinal Cord. By Harris E. Santee. 2 Ibid. THE NERVOUS SYSTEM 
964 
Cutaneous Areas Corresponding to the Sensory Segments of the Spinal Cord.-These 
are shown in Figs. 627 and 628. 
Muscular Supply from Motor Segments of the Cord.-This is shown in Fig. 628. 
LOCATION OF THE SEGMENTS FOR 
SENSIBILITY. 
MOTILITY 
Smell 
Sight 
, Sphincter iridis 
Ciliaris 
Rectus int., levator palpebr. ftup, 
Rectus inf. and sup. 
' Obi. infer. 
' Obi. super. 
' Masseter, temporal, pterygoids 
Rectus extern. 
Occipitofront., orbicularis oculi (upper facial} 
Muscles of expression (lower facial) 
Palatal and pharyngeal muscles 
Muscles of the larynx 
Muscles of the tongue 
Sternocleidomastoid 
Deep muscles of the neck 
Scaleni 
Frontal region 
Eye 
Face 
Tongue 
Taste 
Hearing 
Pharynx 
Larynx 
Esophagus 
Thoracic and abdominal 
viscera 
Occipital region 
Front of neck 
Back of neck 
Shoulder 
Musculo- ■ 
spiral n. 
Median n. 
Ulnar n. 
Trapezius, serratus anticus 
Diaphragm 
' Delt., biceps, pectoral, maj. (clavic. portion) 
' Brachial, antic., supinator longus 
' Triceps, latis. dorsi,pect. maj. (costal " ) 
Arm 
Supply of 
' Extensor es carpi et digitorum 
1 Flexores carpi et digitorum 
Forearm 
Interossei, lumbricales 
Thenar, hypothenar 
Hand 
Nipple 
Thorax 
Epigastrium 
Epigastric reflex 
Abdomen 
Navel 
Inferior abdominal reflex 
Intercostals 
Muscles of the bach 
Abdominal muscle# 
Gluteal region 
Inguinal region 
Hips 
Iliopsoas 
Sartorius 
Adductors 
Abductors 
Thigh ■ 
Anterior 
Median 
External 
Posterior 
Thigh 
Leg 
Internal 
External 
Quadriceps' 
Flexors ' 
Extensors ' 
Leg 
Foot, 
Scrotum, penis, etc. 
Bladder, rectum: 
- Peronei 
Flexors, extensors of the foot and toes 
Glutei (?) 
Anus 
Perineal 
Vesical 
Rectal 1 
Musculature 
Fig. 628.-Explanation of abbreviations: tr. olf., olfactory tract; c. g. I., lateral geniculate body; p, r, cr, A, 
indicate approximately the location of the reflex centres for the pupillary (p), the respiratory (r), cremasteric (cr), 
patellar (pat), and tendo Achillis (.4) reflexes. The vesical centre lies in the third and fourth sacral segments; 
the anal centre in the fourth and fifth (represented by circles); the centres for erection, ejaculation, labor 
pains (?) are probably also situated in this region. In reality, the divisions between the various segments are, 
of course, not so sharp as they are shown in the diagram, so that a given muscle or cutaneous region derives 
some of its controlling nerve-roots from the segments lying immediately above and below the principal segment. 
The sensory segment for any given region is regularly somewhat higher than the corresponding motor segment. 
(Jakob.) 
THE SPINAL NERVES (NERVI SPINALES). 
The spinal nerves are so called because they take their origin from the spinal 
cord, and are transmitted through the intervertebral foramina on either side of the 
spinal column. There are thirty-one pairs of spinal nerves, which are arranged THE ROOTS OF THE SPINAL NERVES 
965 
into the following groups, corresponding to the region of the spine through which 
they pass: 
Cervical . . . ... . .8 pairs. 
Thoracic or Dorsal . . . . . 12 " 
Lumbar ....... 5 " 
Sacral ....... 5 " 
Coccygeal ...... 1 " 
It will be observed that each group of nerves corresponds in number with the 
vertebrae in that region, except the cervical and coccygeal. Sometimes there is no 
thirty-first pair. Occasionally below the thirty-first pair there may be one or even 
two filamentous pairs which do not pass out of the spinal canal. 
Each spinal nerve arises by two roots, an anterior or motor root and a posterior 
or sensory root, the latter being distinguished by a ganglion, termed the spinal 
ganglion. 
The Roots of the Spinal Nerves (Figs. 538, 540, 541, 629, 630, 631). 
The Anterior or Ventral Root (radix anterior).-The superficial origin is 
from the antero-lateral columns of the cord, corresponding to the situation of the 
anterior cornu of gray matter. Each root 
is composed of from four to eight fila- 
ments (fila radicularia). 
The deep origin can be traced through 
the antero-lateral column; the roots, after 
penetrating horizontally through the lon- 
gitudinal fibres of this tract, enter the gray 
substance, where their fibrils diverge in 
several directions: some passing inward, 
are continued across the anterior com- 
missure in front of the central canal, to 
become continuous with the axis-cylinder 
processes of the large cells of the anterior 
cornu of the opposite side; others termi- 
nate in the mesial group of cells of the 
anterior column of the same side; other 
fibrils pass outward, to become continuous 
with the axis-cylinder processes of the 
group of cells in the lateral part of the 
anterior column. 
The Posterior or Dorsal Root (radix 
posterior).-The superficial origin is by 
filaments (fila radicularia), from the pos- 
tero-lateral fissure of the cord. The real 
origin of these fibres is from the nerve- 
cells in the posterior root ganglion, from 
which they can be traced into the cord 
in two main bundles, the course of which 
has already been studied (p. 847). 
The anterior roots are smaller than the 
posterior, devoid of ganglionic enlargement, and their component fibrils are 
collected into two bundles near the intervertebral foramina. 
The posterior roots of the nerves are larger, but the individual filaments are 
finer and more delicate than those of the anterior. As their component fibrils 
DORSAL 
NERVE 
ROOTS 
VENTRAL 
NERVE 
L ROOTS 
DORSAL 
ROOTS " 
LIGAMENTUM 
DENTICULATUM 
DURA 
OPENED 
VENTRAL 
ROOTS 
SPINAL NERVE 
IN ITS PIAL 
SHEATH 
DORSAL 
ROOTS ' 
VENTRAL 
ROOTS 
DORSAL 
ROOTS' 
LIGAMENTUM 
DENTICULATUM 
VENTRAL ROOTS 
SPINAL NERVE 
IN ITS SHEATH 
Fig. 629.-A portion of the spinal cord, showing 
its right lateral surface. The dura is opened and 
arranged to show the nerve roots. (Testut.) 966 
THE NERVOUS SYSTEM 
pass outward toward the aperture in the dura mater, they coalesce into two 
bundles, receive a tubular sheath from that membrane, and enter the ganglion 
(Figs. 629, 630, and 631) which is developed upon each root. 
The posterior root of the first cervical nerve forms an exception to these char- 
acters. It is smaller than the anterior, has occasionally no ganglion developed 
upon it, and when the ganglion exists, it is often situated within the dura mater. 
The first cervical may have a rudimentary posterior root or no posterior root. 
^INTERNAL BRANCH 
GAPTGLION 
'POSTERIOR PRIMARY 
DIVISION 
'EXTERNAL BRANCH 
ANTERIOR PRIMARY 
DIVISION 
RAMUS COMMUNICANS 
Fig. 630.-Plan of the constitution of a spinal nerve. (W. Keiller, in Gerrish's Text-book of Anatomy.) 
Within the spinal canal the nerve-roots are separated from each other by the 
ligamentum denticulatum (Fig. 629). In the cervical region the spinal portion 
of the spinal accessory nerve separates the roots. Each root obtains a covering 
of pia mater, which becomes continuous with the neurilemma; " the arachnoid 
invests each root as far as the point where it meets with the dura mater; the two 
roots, after piercing the dura separately, are enclosed by it in a single tubular 
sheath, in which is included the spinal ganglion of the dorsal root."1 
Neuraxis of Peripheral 
Sensory Neurone 
Spinal Ganglion. 
Dendrite of 
Peripheral Sensory 
Neurone 
Anterior Horn of Gray Matter 
of Spinal Cord 
"Neuraxis of Peripheral Motor Neurone 
-Sympathetic Ganglion 
Nerve Trunk 
Neuraxis of 
Sympathetic Neurone 
Fig. 631.-Diagram to show the composition of a peripheral nerve-trunk. (Biihm and Davidoff.) 
The Ganglia of the Spinal Nerves (Ganglia Spinales) (Figs. 629, 630, 631). 
A ganglion is developed upon the posterior root of each of the spinal nerves. 
The ganglion upon the posterior root of the first cervical nerve may be rudimentary 
or absent. These ganglia are of an oval form and of a reddish color; they bear 
a proportion in size to the nerves upon which they are formed, and are placed 
in the intervertebral foramina, external to the point where the nerves perforate 
1 Cunningham's Text-book of Anatomy. POINTS OF EMERGENCE OF THE SPINAL NERVES 
967 
the dura mater. Each ganglion is bifid internally, where it is joined by the 
two bundles of the posterior root, the two portions being united into a single 
mass externally. The ganglia upon the first and second cervical nerves form an 
exception to these characters, being placed on the arches of the vertebrae over 
which the nerves pass. The ganglia of the sacral nerves are placed within the 
spinal canal; and that on the coccygeal nerve, also in the canal, is situated at 
some distance from the origin of the posterior root. 
The ganglion in an embryo is composed of bipolar nerve-cells. In an adult 
the bipolar nerve-cells by fusion of their two poles form unipolar nerve-cells. The 
process of each unipolar cell divides into two a short distance from the cell. One 
of the processes from each cell passes to the spinal cord, and the other passes 
into the spinal nerve. On the dorsal roots of the lumbar and sacral nerves, 
between the spinal ganglia and the cord, small cellular masses occasionally exist. 
They are called accessory spinal ganglia (ganglia aberrantia). 
Distribution of the Spinal Nerves. 
Immediately beyond the ganglion the two roots coalesce, their fibres inter- 
mingle, and the trunk thus formed constitutes the spinal nerve; it passes out 
of the intervertebral foramen, and divides into a posterior primary division for 
the supply of the posterior part of the body, and an anterior primary division 
for the supply of the anterior part of the body (Fig. 630). Each division contains 
fibres from both roots. 
Before dividing, each spinal nerve gives off a small recurrent or meningeal 
branch (ramus meningeus) (Fig. 630), which is joined by a filament from the 
communicating branch of the sympathetic (ramus communicans) (Fig. 630), which 
connects the ganglion with the anterior division. The meningeal branches unite 
and form one nerve, which passes inward through the intervertebral foramen and 
supplies the dura mater, sending branches to the vertebrae and vertebral ligaments. 
The Posterior Primary Divisions (rami posteriores) (Fig. 630).-The posterior pri- 
marydivisions of the spinal nerves are generally smaller than the anterior; they arise 
from the trunk resulting from the union of the roots, in the intervertebral foramina; 
and, passing backward, divide into internal and external branches, which are dis- 
tributed to the muscles and integument behind the spine. The posterior primary 
divisions of the spinal nerves form two small plexuses, the posterior cervical plexus 
and the posterior sacral plexus. The first cervical, the fourth and fifth sacral, and 
the coccygeal nerves do not divide into external and internal branches. 
The Anterior Primary Divisions (rami anteriores) (Fig. 630).-The anterior 
primary divisions of the spinal nerves supply the parts of the body in front of 
the spine, including the limbs. They are for the most part larger than the 
posterior primary divisions. Each division, soon after its origin, receives a slen- 
der filament from the sympathetic, which is called the gray ramus communi- 
cans. In the dorsal region the anterior primary divisions of the spinal nerves 
are quite separate from each other, and are uniform in their distribution; but in the 
cervical, lumbar, and sacral regions they form intricate plexuses previous to their 
distribution. The anterior primary divisions of certain dorsal, lumbar, and sacral 
nerves give off a delicate collection of nerve filaments to the sympathetic cord. 
These are called the white rami communicantes or the visceral branches of the spinal 
nerves. 
Points of Emergence of the Spinal Nerves. 
The roots of the spinal nerves from their origin in the cord run obliquely 
downward to their point of exit from the intervertebral foramina, the amount of 
obliquity varying in different regions of the spine, and being greater in the lower THE NERVOUS SYSTEM 
968 
than the upper part. The level of their emergence from the cord is within certain 
limits variable, and of course does not correspond to the point of emergence of 
the nerve from the intervertebral foramina. 
The following table, from Macalister, shows as accurately as can be shown the 
relation of these points of origin from the spinal cord to the bodies and spinous 
processes of the vertebrae: 
Level of body of 
No. of nerve. 
Level of tip of 
spine of 
Level of body of 
No. of nerve. 
Level of tip of 
spine of 
C. 1 
C. 1 
D. 8 
9 
7 d. 
2 
... 
9 
10 
8 d. 
3 
1 c. 
10 
11 
9 d. 
3 
4 
2 c. 
... 
12 
10 d. 
4 
5 
3 c. 
11 
L. 1 
11 d. 
5 
6 
4 c. 
2 
6 
7 
8 
5 c. 
6 c. 
12{ 
3 
4 
| 12 d. 
7 
D. 1 
7 c. 
r 
5 
D. 1 
2 
1 d. 
S. 1 
2 
3 
... 
L. 1-! 
2 
3 
4 
2 d. 
3 
4 
5 
3 d. 
4 
1 1 L. 
5 
6 
4 d. 
5 
6 
7 
5 d. 
... 
C. 1 
7 
8 
6 d. 
L. 2 
THE CERVICAL NERVES (NN. CERVICALES). 
The Roots of the Cervical Nerves. 
The roots of the cervical nerves increase in size from the first to the fifth, and 
then remain the same size to the eighth. The posterior roots bear a proportion 
to the anterior as 3 to 1, which is much greater than in any other region, the 
individual filaments being also much larger than those of the anterior roots. The 
posterior root of the first cervical is an exception to this rule; it is smaller than 
the anterior root. In direction the roots of the cervical are less oblique than 
those of the other spinal nerves. The first cervical nerve is directed a little upward 
and outward; the second is horizontal; the others are directed obliquely down- 
ward and outward, the lowest being the most oblique, and consequently longer 
than the upper, the distance between their place of origin and their point of exit 
from the spinal canal never exceeding the depth of one vertebra. 
The First Cervical or Suboccipital Nerve (n. suboccipitalis) (Fig. 632).-The 
posterior root may be rudimentary or absent. The trunk of the first cervical 
nerve leaves the spinal canal between the occipital bone and the posterior arch 
of the atlas (Figs. 16 and 202). 
The Trunk of the Second Cervical Nerve leaves the spinal canal between the 
posterior arch of the atlas and the lamina of the axis; and the Eighth (the last), 
between the last cervical and first dorsal vertebrae. 
Each nerve, at its exit from the intervertebral foramen, divides into a posterior 
and an anterior division. The anterior divisions of the four upper cervical nerves 
form the cervical plexus. The anterior divisions of the four lower cervical nerves, 
together with the first dorsal, form the brachial plexus. 
The Posterior or Dorsal Divisions of the Cervical Nerves (Rami Posteriores) 
(Fig. 633). 
The Posterior Division of the First Cervical Nerve (Figs. 632 and 633) differs 
from the posterior divisions of the other cervical nerves in not dividing into an 
internal and external branch. It is larger than the anterior division, and escapes 
from the spinal canal between the occipital bone and the posterior arch of the atlas, POSTERIOR OR DORSAL DIVISIONS OF CERVICAL NERVES 
969 
lying beneath the vertebral artery. It enters the suboccipital triangle formed by 
the Rectus capitis posticus major, the Obliquus superior and Obliquus inferior, 
and, by muscular branches, supplies the Recti and Obliqui muscles, and the 
Complexus. From the branch which supplies the Inferior oblique a communi- 
cating filament is given off which joins the second cervical nerve. This nerve 
also occasionally gives off a cutaneous filament, which accompanies the occipital 
artery and communicates with the occipitalis major and minor nerves. 
The Posterior Division of the Second Cervical Nerve is three or four times greater 
in diameter than the anterior division, and the largest of all the posterior 
cervical divisions. It emerges from the spinal canal between the posterior arch 
of the atlas and lamina of the axis, below the Inferior oblique. It supplies a twig 
to this muscle, and receives a communicating filament from the first cervical. 
It then divides into an internal and an external branch. 
The internal branch, called, from its size and distribution, the great occipital nerve 
(occipitalis major) (Figs. 632 and 633), ascends obliquely inward between the 
Obliquus inferior and Complexus, and pierces the latter muscle and the Trapezius 
GREAT OCCIPI- 
TAL NERVE 
OBLIQUUS 
'SUPERIOR 
ANTERIOR PRIMARY DIVI- 
SION OF FIRST CERVICAL 
R ECTUS* CAPITIS 
LATERALIS 
BRANCH TO COMPLEXUS-CUT 
VERTEBRAL ARTERY 
■POSTERIOR PRIMARY DIVI- 
SION OF FIRST CERVICAL 
-ANASTOMOTIC BRANCH 
VERTEBRAL ARTERY. 
-CUT 
■ANASTOMOTIC 
-THIRD CERVICAL 
POSTERIOR PRIMARY DIVI- 
SION OF FIRST CERVICAL | 
OBLIQUUS 
I INFERIOR 
RECTUS 
MAJOR 
Fig. 632.-Dorsal primary divisions of the upper three cervical nerves. (Testut.) 
near their attachments to the cranium. It is now joined by a filament from the 
posterior division of the third cervical nerve, the anastomotic, and, ascending on 
the back part of the head with the occipital artery, divides into two branches, 
which supply the integument of the scalp as far forward as the vertex, com- 
municating with the occipitalis minor. It gives off an auricular branch to the 
back part of the ear and muscular branches to the Complexus. 
The external branch is often joined by the external branch of the posterior 
division of the third cervical nerve, and supplies the Splenius, Trachelo-mastoid, 
and Complexus 
The Posterior Division of the Third Cervical Nerve (Figs. 632 and 633) is smaller 
than the preceding, but larger than the fourth; it differs from the posterior 
divisions of the remaining cervical nerves in its supplying an additional filament, 
the third occipital nerve, to the integument of the occiput. The posterior division 
of the third nerve, like the others, divides into an internal and external branch. 
The internal or cutaneous branch passes between the Complexus and Semi- 
spinalis, and, piercing the Splenius and Trapezius, supplies the skin over the 
latter muscle. 970 
THE NERVOUS SYSTEM 
The external branch joins with that of the posterior division of the second to 
supply the Splenius, Trachelo-mastoid, and Complexus. 
The third or least occipital nerve (n. occipitalis minimus or n. occipitalis tertius) 
(Fig. 632) arises from the internal or cutaneous branch of the posterior division of 
the third cervical nerve, beneath the Trapezius; it then pierces that muscle, and 
supplies the skin on the lower and back part of the head. It lies to the inner side 
of the occipitalis major, with which it is connected. 
Fig. 633.-Posterior divisions of the upper cervical nerves. 
The posterior division of the suboccipital nerve and the internal branches of 
the posterior divisions of the second and third cervical nerves are occasionally 
joined beneath the Complexus by communicating branches. This communication 
is described by Cruveilhier as the posterior cervical plexus. 
The Posterior Divisions of the Fourth, Fifth, Sixth, Seventh, and Eighth Cervical 
Nerves pass backward, and divide, behind the Intertransversales muscles, into 
internal and external branches. 
The internal branches, the larger, are distributed differently in the upper and 
lower part of the neck. Those derived from the fourth and fifth nerves pass THE ANTERIOR DIVISIONS OF THE CERVICAL NERVES 
971 
between the Coinplexus and Semispinalis muscles, and, having reached the spin- 
ous processes, perforate the aponeurosis of the Splenius and Trapezius, and are 
continued outward to the integument over the Trapezius, whilst those derived 
from the three lowest cervical nerves are the smallest, and are placed beneath 
the Semispinalis colli, which they supply, and then pass into the Interspinalis, 
Multifidus spinae, and Complexus, and send twigs through this latter muscle to 
supply the integument near the spinous processes (Hirschfeld). 
The external branches supply the muscles at the side of the neck-viz., the 
Cervicalis ascendens, Transversalis colli, and Trachelo-mastoid. 
The Anterior Divisions of the Cervical Nerves (Rami Anteriores) 
The Anterior Division of the First Cervical Nerve (Fig. 635) is of small size. 
It escapes from the spinal canal through a groove upon the posterior arch of the 
atlas. In this groove it lies beneath the vertebral artery, to the inner side of the 
Rectus capitis lateralis. As it crosses the foramen in the transverse process of 
the atlas it receives a filament from the sympathetic. It then descends in front 
of the transverse process, to communicate with an ascending branch from the 
second cervical nerve. 
Communicating filaments from the loop between this nerve and the second 
cervical nerve join the pneumogastric, the hypoglossal, and sympathetic, and 
some branches are distributed to the Rectus lateralis and the two Anterior recti. 
The fibres which communicate with the hypoglossal simply pass through the 
latter nerve to become for the most part the descendens hypoglossi. According 
to Valentin, the anterior division of the suboccipital nerve distributes filaments 
to the occipito-atlantal articulation and to the mastoid process of the temporal 
bone. 
The Anterior Division of the Second Cervical Nerve (Fig. 635) escapes from the 
spinal canal, between the posterior arch of the atlas and the lamina of the axis, and, 
passing forward on the outer side of the vertebral artery, divides in front of the 
Intertransverse muscle into an ascending branch, which joins the first cervical; and 
one or two descending branches, which join the third cervical. It gives off the 
small occipital; a branch to assist in forming the great auricular; another to assist 
in forming the superficial cervical; one of the communicantes hypoglossi, and a 
filament to the Sterno-mastoid, which communicates in the substance of the 
muscle with the spinal accessory. 
The Anterior Division of the Third Cervical Nerve (Fig. 635) is double the size of 
the preceding. At its exit from the intervertebral foramen it passes downward and 
outward beneath the Sterno-mastoid muscle, and divides into two branches. The 
ascending branch joins the anterior division of the second cervical; the descending 
branch passes down in front of the Scalenus anticus muscle and communicates 
with the fourth cervical. It gives off the larger part of the great auricular and 
superficial cervical nerves; one of the communicantes hypoglossi; a branch to the 
supraclavicular nerves; a filament to assist in forming the phrenic; and muscular 
branches to the Levator anguli scapulae and Trapezius; this latter nerve com- 
municates beneath the muscle with the spinal accessory. Sometimes the nerve 
to the Scalenus medius is derived from this source. 
The Anterior Division of the Fourth Cervical Nerve (Fig. 635) is of the same size as 
the preceding. It receives a branch from the third, sends a communicating branch 
to the fifth cervical, and, passing downward and outward, divides into numerous 
filaments, which cross the posterior triangle of the neck, forming the supraclavicular 
nerves. It gives a branch to the phrenic nerve, while it is contained in the inter- 
transverse space, and sometimes a branch to the Scalenus medius muscle. It also 
gives a branch to the Levator anguli scapulae and to the Trapezius, which unites 972 
THE NERVOUS SYSTEM 
with the branch given off from the third nerve, and communicates beneath the 
muscle with the spinal accessory. 
The Anterior Divisions of the Fifth, Sixth, Seventh, and Eighth Cervical Nerves are 
remarkable for their size. They are much larger than the preceding nerves, and 
are all of equal dimensions. They assist in the formation of the brachial plexus. 
The Cervical Plexus (Plexus Cervicalis) (Figs. 634 and 635). 
The cervical plexus is formed by the anterior divisions of the four upper 
cervical nerves. It is situated opposite the four upper cervical vertebrae, rest- 
ing upon the Levator anguli scapulae and Scalenus medius muscles, and covered 
in by the Sterno-mastoid. 
Its branches may be divided into two groups, superficial and deep, which may 
be thus arranged: 
Occipitalis minor. 
Auricularis magnus. 
Superficialis colli. 
Ascending . 
Superficial 
Suprasternal. 
Supraclavicular. 
Supra-acromial. 
Descending 
Supraclavicular 
Communicating. 
Muscular. 
Communicantes hypoglossi. 
Phrenic. 
Internal 
Deep 
External 
Communicating. 
L Muscular. 
The Superficial Branches of the Cervical Plexus. The Small Occipital Nerve 
(n. occipitalis minor) (Fig. 634).-The small occipital nerve arises from the second 
cervical nerve, sometimes also from the third; it curves round the posterior border 
of the Sterno-mastoid, and ascends, running parallel to the posterior border of the 
muscle, to the back part of the side of the head. Near the cranium it perforates 
the deep fascia, and is continued upward along the side of the head behind the 
ear, supplying the integument, and communicating with the occipitalis major, the 
auricularis magnus, and with the posterior auricular branch of the facial. 
This nerve gives off an auricular branch, which supplies the integument of the 
upper and back part of the auricle, communicating with the mastoid branch 
of the auricularis magnus. The auricular branch is occasionally derived from 
the great occipital nerve. The occipitalis minor varies in size; it is occasionally 
double. 
The Great Auricular Nerve (n. auricularis magnus) (Fig. 634).-The great 
auricular nerve is the largest of the ascending branches. It arises from the 
second and third cervical nerves, winds around the posterior border of the Sterno- 
mastoid, and, after perforating the deep fascia, ascends upon that muscle beneath 
the Platysma to the parotid gland, where it divides into facial, auricular, and 
mastoid branches. 
The Facial Branches pass across the parotid, and are distributed to the integ- 
ument of the face over the parotid gland; others penetrate the substance of the 
gland and communicate with the facial nerve. 
The Auricular Branches ascend to supply the integument of the back of the 
pinna, except at its upper part, communicating with the auricular branches of 
the facial and pneumogastric nerves. A filament pierces the pinna to reach its 
outer surface, where it is distributed to the lobule and lower part of the concha. THE CERVICAL PLEXUS 
973 
The Mastoid Branch communicates with the occipitalis minor and the posterior 
auricular branch of the facial, and is distributed to the integument behind the 
ear. 
The Superficial Cervical Nerve or the Superficialis Colli (n. cutaneus colli) (Fig. 
634).-The superficial cervical nerve or the superficialis colli arises from the 
second and third cervical nerves, turns around the posterior border of the Sterno- 
POSTERIOR 
AURICULAR 
NERVE 
GREAT 
OCCI PITAL 
GREAT 
AURICULAR 
(posterior branch) 
SMALL, 
OCCIPITAL 
GREAT 
AURICULAR 
(anterior branches) 
THIRD 
OCCI PITAL 
BRANCHES 
OF FACIAL 
NERVE 
SPINAL 
ACCESSORY 
(external branch) 
SCALENUS 
MEDIUS 
MUSCLE 
IN FRAMAN DI BULAR 
BRANCH OF 
FACIAL 
SUPERFICIAL 
CERVICAL 
NERVES 
SUPRACLAVICULAR - 
BRANCHES TO 
TRAPEZIUS 
SUPRACLAVICULAR 
NERVES. 
(acromial 
branches) 
OMO-HYOIDEUS 
muscle (pos- 
terior belly) 
SUPRACLAVICULAR 
nerves (sternal 
branches) 
SUPRACLAVICULAR 
nerves (clavicular 
branches) 
Fig. 634.-The cutaneous branches of the right cervical plexus, viewed from the right. The Platysma 
has been partly removed. (Spalteholz ) 
mastoid about its middle, and, passing obliquely forward beneath the external 
jugular vein to the anterior border of the muscle, perforates the deep cervical 
fascia, and divides beneath the Platysma into two branches, which are distributed 
to the antero-Iateral parts of the neck. 
'Phe Ascending Branch or Branches (rami superiores) gives a filament which 
accompanies the external jugular vein; it then passes upward to the sub- 
maxillary region, and divides into branches, some of which form a plexus with 
the cervical branches of the facial nerve beneath the Platysma; others pierce 974 
THE NERVOUS SYSTEM 
that muscle and are distributed to the integument of the upper half of the neck, 
at its forepart, as high as the chin. 
The Descending Branches (rami injeriores), usually represented by two or more 
filaments, pierce the Platysma, and are distributed to the integument of the side 
and front of the neck, as low as the sternum. 
The Descending or Supraclavicular Branches (nn. supraclavicidares) (Fig. 634).- 
The descending or supraclavicular branches arise from the third and fourth 
cervical nerves; emerging beneath the posterior border of the Sterno-mastoid, they 
descend in the posterior triangle of the neck beneath the Platysma and deep 
cervical fascia. Near the clavicle they perforate the fascia and Platysma to 
become cutaneous, and are arranged, according to their position, into three 
groups. 
The Inner or Suprasternal Branches (nn. supraclaviculares anteriores) cross 
obliquely over the external jugular vein and the clavicular and sternal attach- 
ments of the Sterno-mastoid muscle, and supply the integument as far as the 
median line. They furnish one or two filaments to the sterno-clavicular joint. 
The Middle or Supraclavicular Branches (nn. supraclaviculares medii) cross the 
clavicle, and supply the integument over the Pectoral and Deltoid muscles, com- 
municating with the cutaneous branches of the upper intercostal nerves. 
The External or Supra-acromial Branches (nn. supraclaviculares posteriores) pass 
obliquely across the outer surface of the Trapezius and the acromion, and supply 
the integument of the upper and back part of the shoulder. 
The Deep Branches of the Cervical Plexus (Fig. 635). Internal Series. 
The Communicating Branches.-The communicating branches consist of several 
filaments which pass from the loop between the first and second cervical nerves 
in front of the atlas to the pneumogastric, hypoglossal, and sympathetic; of 
branches from all four cervical nerves to the superior cervical ganglion of the 
sympathetic, together with a branch from the fourth to the fifth cervical. 
Muscular Branches.-Muscular branches supply the Anterior recti and Rectus 
lateralis muscles; they proceed from the first cervical nerve, and from the loop 
formed between it and the second. 
The Communicantes Hypoglossi (Fig. 635).-The communicantes hypoglossi 
consist usually of two filaments, one being derived from the second and the other 
from the third cervical. These filaments pass downward on the outer side of the 
internal jugular vein, cross in front of the vein a little below the middle of the 
neck, and form a loop with the descendens hypoglossi in front of the sheath of 
the carotid vessels. Occasionally, the junction of these nerves takes place within 
the sheath. 
The Phrenic or the Internal Respiratory Nerve of Bell (n. phrenicus) (Figs. 635 and 
636).-The phrenic or the internal respiratory nerve of Bell arises chiefly from the 
fourth cervical nerve, with a few filaments from the third and a communicating 
branch from the fifth. It descends to the root of the neck, running obliquely 
across the front of the Scalenus anticus muscle, and beneath the Sterno-mastoid 
muscle, the posterior belly of the Omohyoid muscle, and the Transversalis colli 
and suprascapular vessels. It next passes over the first part of the subclavian 
artery, between it and the subclavian vein, and, as it enters the chest, crosses the 
internal mammary artery near its origin. Within the chest it descends nearly 
vertically in front of the root of the lung and by the side of the pericardium, 
between it and the mediastinal portion of the pleura, to the Diaphragm, where 
it divides into branches, some few of which are distributed to its thoracic surface, 
but most of which separately pierce that muscle and are distributed to its under 
surface (rami phrenicoabdominales). 
The two phrenic nerves differ in their length, and also in their relations at the 
upper part of the thorax. THE CERVICAL PLEXUS 
975 
The right phrenic nerve is situated more deeply, and is shorter and more 
vertical in direction than the left; it lies on the outer side of the right vena 
innominata and superior vena cava. 
The left phrenic nerve is rather longer than the right, from the inclination of 
the heart to the left side, and from the Diaphragm being lower on this than on the 
opposite side. It enters the thorax behind the left innominate vein, and crosses 
in front of the vagus and the arch of the aorta and the root of the lung. In the 
thorax each phrenic nerve is accompanied by a branch of the internal mammary 
artery, the comes nervi phrenici. 
I 
n 
in 
IV 
v 
Red. Cap. Lat. 
Red. Ant. Major 
)Red. Ant. Minor 
To Sympathetic 
To Hypoglossal 
To Vagus 
'To Scalp and Occipito Frontalis 
s»iall OcciB^0, 
To Auricle 
Sterno-Mastoid 
C.with Sphi.Acces. 
Mastoid 
Auricular 
1 Facial 
Gt. 
^e?. c . 
• Cervical 
(Cummunleans Hypoglossi 
~>Lev. Ang. Scap. 
Trapezius 
C. with Spin. Accessory 
Sternal 
Clavicular 
Acromial 
Phrenic 
Scalen. Medius 
Fig. 635.-Plan of the cervical plexus. 
Each nerve supplies filaments to the Diaphragm, pericardium, and pleura, 
and near the chest is joined by a filament from the sympathetic, and, occasion- 
ally, by one from the union of the descendens hypoglossi with the spinal nerves; 
this filament is found, according to Swan, only on the left side. The phrenic fre- 
quently receives a filament from the nerve to the Subclavian muscle. Branches 
have been described as passing to the peritoneum. 
From the right nerve one or two filaments pass to join in a small ganglion with 
phrenic branches of the solar plexus; and branches from this ganglion are 
distributed to the hepatic plexus, the suprarenal capsule, and inferior vena 
cava. 
From the left nerve filaments pass to join the phrenic plexus of the sympathetic, 
but without any ganglionic enlargement. 976 
THE NERVOUS SYSTEM 
Surgical Anatomy.-Irritation of the phrenic nerve causes hiccough and persistent cough. 
Bilateral paralysis of the phrenic causes death from paralysis of the Diaphragm. This form of 
death is seen by the surgeon in fracture-dislocation of the third cervical vertebra. Division of 
the phrenic on one side is not fatal, and is occasionally practised by the surgeon in removing 
a tumor of the neck. In Hearn's and Franklin's cases of removal of the pneumogastric, the 
phrenic was also divided. Unilateral division of the phrenic nerve causes paralysis of the corre- 
sponding half of the Diaphragm, which is difficult of recognition, because, as Gowers points out, 
the patient can still take deep inspirations, the thoracic muscles not being paralyzed. 
PNEUMOGASTRIC 
ANTERIOR PRIMARY 
DIVISION OF. 
FOURTH CERVICAL 
PHRENIC 
PHRENIC, 
INFERIOR 
CERVICAL 
GANGLION 
BRACHIAL 
PLEXUS 
INFERIOR 
'LARYNGEAL 
NERVE TO 
SUBCLAVIUS 
MUSCLE 
INFERIOR 
LARYNGEAL 
COMMUNICATING 
BRANCH FROM 
brachial plexus 
PNEUMOGASTRIC 
thoracic cardiac 
branch of 
pneumogastric 
■INFERIOR 
laryngeal 
ROOT OF 
LUNG 
anterior 
PULMONARY 
PERICARDIAL 
branch' 
anterior 
■ PULMONARY 
PLEXUS 
PHRENICO- 
ABDOMINAL 
BRANCH 
Fig. 636.-The phrenic nerve and its relations with the vagus nerve. (Toldt.) 
RAMIFICATIONS 
OF PHRENIC 
The Deep Branches of the Cervical Plexus. External Series. Communicating 
Branches.-The deep branches of the external series of the cervical plexus com- 
municate with the spinal accessory nerve, in the substance of the Sterno-mastoid 
muscle, in the posterior triangle, and beneath the Trapezius. 
Muscular Branches.-Muscular branches are distributed to the Sterno-mastoid, 
Trapezius, Levator anguli scapulae, and Scalenus medius. 
The branch for the Sterno-mastoid is derived from the second cervical; the 
Trapezius and Levator anguli scapulae receive branches from the third and fourth. THE BRACHIAL PLEXUS 
977 
The Scalenus medius is derived sometimes from the third, sometimes the fourth, 
and occasionally from both nerves. 
Surgical Anatomy.-The cervical plexus may be damaged by wounds or contusions, which 
may or may not be associated with fracture of the clavicle. Paralysis ensues, the extent depend- 
ing on the degree of damage. After a contusion the paralysis is apt to be temporary and to 
be followed by pain and muscular spasm in the arm. Paralysis of the arm due to plexus injury 
may be partial or complete. In some cases there is complete motor palsy and partial sensory 
palsy, the sensory impulses passing along undamaged collaterals. In certain spasmodic diffi- 
culties the surgeon occasionally stretches the cervical plexus. It is reached by an incision at the 
posterior margin of the Sterno-cleido-mastoid muscle. This incision begins two inches below 
the level of the tip of the mastoid and is carried downward for three inches. 
The Brachial Plexus (Plexus Brachialis) (Figs. 637, 638, 639). 
The brachial plexus is formed by the union of the anterior divisions of the 
four lower cervical and the greater part of the first dorsal nerves, receiving usually 
ANTERIOR 
DIVISION OF 
FOURTH CERVICAL' 
DESCENDING 
BRANCH OF 
HYPOGLOSSAL 
DORSALIS' 
SCAPUL/E 
ANSA 
HYPOGLOSSI 
LONG 
THORACIC" 
PHRENIC 
SUPRASCAPULAR 
THYROID 
AXIS 
INTERNAL 
MAMMARY 
ARTERY 
SUBCLAVIAN 
BRANCH TO 
PHRENIC 
ANTERIOR 
THORACIC 
Fig. 637.,-The right brachial plexus with its short branches, viewed from in front. The sterno-cleido-mastoid 
and trapezius muscles have been completely, the omohyoid and subclavian have been partially, removed; a piece 
has been sawed out of the clavicle; the pectoralis muscles have been incised and reflected. (Spalteholz.) 
a fasciculus from the fourth cervical nerve, and frequently one from the second 
dorsal nerve. It extends from the lower part of the side of the neck to the axilla. 
It is very broad, and presents little of a plexiform arrangement at its commence- 
ment. It is narrow opposite the clavicle, becomes broad and forms a more dense 
interlacement in the axilla, and divides opposite the coracoid process into numer- 
ous branches for the supply of the upper limb. The nerves which form the plexus 
are all similar in size, and their mode of communication is subject to considerable 
variation, so that no one plan can be given as applying to every case. The follow- 
ing appears, however, to be the most constant arrangement: above the clavicle 978 
THE NERVOUS SYSTEM 
MUSCULOCUTANEOUS 
NERVE 
INTERCOSTO-HUMERAL 
NERVES 
ANTERIOR 
THORACIC 
NERVES 
INTERNAL 
CUTANEOUS 
NERVE 
LESSER INTERNAL 
CUTANEOUS NERVES 
LATERAL CUTA- 
N EOUS BRANCH 
OF FOURTH 
I NTERCOSTAL 
LONG SUBSCAPULAR 
NERVE 
SUBSCAPULAR 
NERVES 
LATERAL CUTANEOUS 
BRANCH OF 
THIRD INTERCOSTAL 
LONG THORACIC 
NERVE 
Fig. 638.-The right brachial plexus (infraclavicular portion) in the axilliary fossa, viewed from below and in 
front. The Pectoralis major and minor muscles have been in large part removed; their attachments have been 
reflected. (Spalteholz.) 
From 4th 
V Cervical 
Rhomboid 
Subclavian 
VI Cervical 
Suprascapular 
C. with Phrenic- 
VII Cervical 
Upper Trunk 
Middle Trunk 
Branches to Longus 
Colli and Scaleni ' 
Anterior division of Upper Trunk 
External Anterior Thoracic 
Anterior division 
of Middle Trunk 
VIII Cem-ieal 
% 
Posterior division of Upper Trunk 
Upper Sub-scapular 
, Middle and Lower 
Sub-scapular 
I Dorsal. 
■V 
Circumflex 
Lower Trunk 
X 
% 
Posterior division of Middle Trunk 
Anterior division of Lower Trunk 
Posterior Thoracic 
Posterior division of Lower Trunk 
Internal Anterior Thoracic 
Musculo-cutaneous 
Lesser Internal Cutaneous 
Internal Cutaneous 
Median 
Ulnar 
Musculo-spiral 
Fig. 639.-Plan of the brachial plexus. THE BRACHIAL PLEXUS 
979 
(pars supraclavicular is} the fifth and sixth cervical unite together soon after their 
exit from the intervertebral foramina to form a common trunk. The eighth cer- 
vical and first dorsal also unite to form one trunk. So that the nerves forming 
the plexus, as they lie on the Scalenus medius external to the outer border of the 
Fig. 640.-Cutaneous nerves of right upper 
extremity. Anterior view. 
Fig. 641.-Cutaneous nerves of right upper 
extremity. Posterior view. 
Scalenus anticus muscle, are blended into three trunks-an upper one, formed 
by the junction of the fifth and sixth cervical nerves; a middle one, consisting 
of the seventh cervical nerve; and a lower one, formed by the junction of the 
eighth cervical and first dorsal nerves. As they pass beneath the clavicle, to 
compose the infraclavicular part of the plexus (pars infraclavicular is}, each of THE NERVOUS SYSTEM 
980 
these three trunks divides into two branches, an anterior and a posterior.1 The 
anterior divisions of the upper and middle trunks then unite to form a common 
cord, which is situated on the 
outer side of the middle part 
of the axillary artery, and is 
called the outer cord of the 
brachial plexus (fasciculus lat- 
eralis). The anterior division 
of the lower trunk passes 
down on the inner side of the 
axillary artery in the middle1 
of the axilla, and forms the 
inner cord of the brachial plexus 
fasciculus medialis). The 
posterior divisions of all three 
trunks unite to form the pos- 
terior cord of the brachial plexus 
fasciculus posterior), which is 
situated behind the second 
portion of the axillary artery. 
From this posterior cord are 
given off the two lower sub- 
scapular nerves, the upper 
subscapular nerve being given 
off from the posterior division 
of the upper trunk prior to its 
junction with the posterior 
division of the lower and mid- 
dle trunks. The posterior cord 
divides into the circumflex 
and musculo-spiral nerves. 
The brachial plexus com- 
municates with the cervical 
plexus by a branch from the 
fourth to the fifth cervical 
nerve, and with the phrenic 
nerve by a branch from the 
fifth cervical, which joins that 
nerve on the Anterior scalenus 
muscle; the fifth and sixth 
cervical nerves are joined by 
filaments to the middle cervical 
ganglion of the sympathetic, 
the seventh and eighth cervical 
to its inferiorganglion, and the 
first dorsal nerve to its first 
thoracic ganglion. Close to 
their exit from the interverte- 
bral foramina the nerves give 
off the filaments to the ganglia. 
Relations.-In the neck, the brachial plexus lies in the posterior triangle, being 
covered by the skin, Platysma, and deep fascia; it is crossed by the posterior belly 
Fig. 642.-Cutaneous nerves of the upper limb, ventral aspect. 
(W. Keiller, in Gerrish's Text-book of Anatomy.) 
' The posterior division of the lower trunk is very much smaller than the others, and is frequently derived 
entirely from the eighth cervical nerve.-Ed. of 15th English edition. THE BRACHIAL PLEXUS 
981 
of the Omo-hyoid muscle and by the transversahs colli artery. When the posterior 
scapular artery arises from the third part of the subclavian it usually passes between 
the roots of the plexus. The plexus lies at first between the Anterior and Middle 
scaleni muscles, and then 
above and to the outer side 
of the subclavian artery; it 
next passes behind the clavicle 
and Subclavius muscle, lying 
upon the first serration of the 
Serratus magnus, and the 
Subscapularis muscles. It is 
in close relation with the apex 
of the lung (Luschka). In the 
axilla it is placed on the outer 
side of the first portion of the 
axillary artery; it surrounds 
the artery in the second part 
of its course, one cord lying 
upon the outer side of that 
vessel, one on the inner side, 
and one behind it, and at the 
lower part of the axillary space 
gives off its terminal branches 
to the upper extremity. 
Branches.-The branches 
of the brachial plexus are 
arranged in two groups-viz., 
those given off above the 
clavicle, and those below the 
clavicle. 
Branches above the Clavicle 
(Figs. 637 and 639).-The 
branches above the clavicle, 
from the pars supraclavicu- 
laris, are-the 
Communicating. 
Muscular. 
Posterior thoracic. 
Suprascapular. 
The Communicating Branch 
(Figs. 636 and 639).-The 
communicating branch with 
the phrenic is derived from the 
fifth cervical nerve or from 
the loop between the fifth and 
sixth; it joins the phrenic on 
the Anterior scalenus muscle. 
The communications with the 
sympathetic have already been 
referred to. 
The Muscular Branches (rami musculares).-The muscular branches supply the 
Longus colli, Scaleni, Rhomboidei, and Subclavius muscles. Those for the 
Longus colli and Scaleni arise from the four lower cervical nerves at their exit 
ULNAR 
'median 
Fig. 643.-Cutaneous nerve of the upper limb, dorsal aspect. 
(W. Keiller, in Gerrish's Text-book of Anatomy.) 982 
THE NERVOUS SYSTEM 
from the intervertebral foramina. The Rhomboid branch is called the posterior 
scapular nerve (n. dorsalis scapulae) (Figs. 637 and 639), arises from the fifth 
External anterior thoracic. 
Internal anterior thoracic. 
Musculo-cutaneous. 
■Median. 
Ulnar. 
Internal cutaneous. 
Musculo-spiral. 
Posterior 
interosseous. 
Radial. 
Anterior 
interosseous. 
Ulnar. 
Dorsal branch. 
Deep branch.- 
Fig. 644.-Nerves of the left upper extremity. THE BRACHIAL PLEXUS 
983 
cervical, pierces the Scalenus medius, and passes beneath the Levator anguli 
scapulae, which it occasionally supplies, to the Rhomboid muscles. The nerve to 
the Subclavius {n. subclavius) is a small filament which arises from the fifth cervical 
at its point of junction with the sixth nerve; it descends in front of the third 
part of the subclavian artery to the Subclavius muscle, and is usually connected 
by a filament with the phrenic nerve. 
The Posterior Thoracic, the Long Thoracic, or the External Respiratory Nerve of Bell 
(n. thoracalis longus) (Figs. 637, 638, 639, and 644).-The posterior thoracic, the 
long thoracic, or the external respiratory nerve of Bell supplies the Serratus 
magnus muscle, and is remarkable for the length of its course. It sometimes 
arises by two roots from the fifth and sixth cervical nerves immediately after 
their exit from the intervertebral foramina, but generally by three roots from 
the fifth, sixth, and seventh nerves. These unite in the substance of the Middle 
scalenus muscle, and, after emerging from it, the nerve passes down behind the 
brachial plexus and the axillary vessels, resting on the outer surface of the Serratus 
magnus. It extends along the side of the chest to the lower border of that muscle, 
supplying filaments to each of the muscular digitations. 
The Suprascapular Nerve (n. suprascapularis) (Figs. 637, 639, and 645).-The 
suprascapular nerve arises from the cord formed by the fifth and sixth cervical 
nerves; passing obliquely outward beneath the Trapezius and the Omo-hyoid, it 
enters the supraspinous fossa below the transverse or suprascapular ligament, 
and, passing beneath the Supraspinatus muscle, curves around the external border 
of the spine of the scapula to the infraspinous fossa. In the supraspinous fossa 
it gives off two branches to the Supraspinatus muscle, and an articular fila- 
ment to the shoulder-joint; and in the infraspinous fossa it gives off two branches 
to the Infraspinatus muscle, besides some filaments to the shoulder-joint and 
scapula 
Branches below the Clavicle (Figs. 638 and 639).-The branches below the 
clavicle, that is, the branches from the pars subclavicularis of the brachial 
plexus, are derived from the three cords of the brachial plexus, in the following 
manner; 
From the Outer Cord.-From the outer cord arise the external anterior thoracic 
nerve, the musculo-cutaneous, and the outer head of the median. 
From the Inner Cord.-From the inner cord arise the internal anterior thoracic 
nerve, the internal cutaneous, the lesser internal cutaneous (nerve of Wrisberg), 
the ulnar, and inner head of the median. 
From the Posterior Cord.-From the posterior cord arise two of the three sub- 
scapular nerves, the third taking origin from the posterior division of the trunk 
formed by the fifth and sixth cervical nerves; the cord then divides into the 
musculo-spiral and circumflex nerves. 
These branches from below the clavicle may be arranged according to the 
parts they supply: 
To the chest 
Anterior thoracic. 
To the shoulder 
Subscapular. 
Circumflex. 
Musculo-cutaneous. 
Internal cutaneous. 
Lesser internal cutaneous. 
Median. 
Ulnar. 
Musculo-spiral. 
To the arm, forearm, and hand THE NERVOUS SYSTEM 
984 
The fasciculi of which these nerves are composed may be traced through the 
plexus to the spinal nerves from which they originate. They are as follows: 
External anterior thoracic from 5th, 6th, and 7th cervical. 
Internal anterior thoracic " Sth cervical and 1st dorsal. 
Subscapular " 5th, 6th, 7th, and 8th cervical. 
Circumflex " 5th and 6th cervical. 
Musculo-cutaneous " 5th and 6th cervical. 
Internal cutaneous " 8th cervical and 1st dorsal. 
Lesser internal cutaneous " 1st dorsal. 
Median " 6th, 7th, and Sth cervical, and 1st dorsal. 
Ulnar " Sth cervical and 1st dorsal. 
Musculo-spiral " 6th, 7th, and 8th cervical, sometimes also 
from the 5th. 
The Anterior Thoracic Nerves (nn. thoracales anteriores} (Figs. 637, 638, and 639). 
-The anterior thoracic nerves, two in number, supply the Pectoral muscles. 
The External or Superficial Anterior Thoracic Nerve (Figs. 637 and 644),the larger 
of the two, arises from the outer cord of the brachial plexus, through which its 
fibres may be traced to the fifth, sixth, and seventh cervical nerves. It passes 
inward, across the axillary artery and vein, pierces the costo-coracoid membrane, 
and is distributed to the under surface of the Pectoralis major muscle. It sends 
down a communicating filament to join the internal anterior thoracic nerve, and 
this communicating filament forms a loop around the inner side of the axillary 
artery. 
The Internal or Deep Anterior Thoracic Nerve arises from the inner cord, and 
through it from the eighth cervical and first dorsal nerves. It passes behind 
the first part of the axillary artery, then curves forward between the axillary 
artery and vein, and joins with the filament from the anterior nerve. It then 
passes to the under surface of the Pectoralis minor muscle, where it divides into 
a number of branches, which supply the muscle on its under surface. Some 
two or three branches pass through the muscle and reach the Pectoralis major. 
The Subscapular Nerves (nn. subscapulares) (Figs. 638 and 639).-The sub- 
scapular nerves arise from the posterior cord of the plexus. There are three 
subscapular nerves, and they supply the Subscapularis, Teres major, and Latis- 
simus dorsi muscles, and give filaments to the shoulder-joint. The fasciculi of 
which they are composed may be traced to the fifth, sixth, seventh, and eighth 
cervical nerves. 
The First, Short or Upper Subscapular Nerve, the smallest, arises from the pos- 
terior division of the upper trunk of origin of the brachial plexus, and enters 
the upper part of the Subscapularis muscle; this nerve is frequently represented 
by two branches. 
The Second or Lower Subscapular Nerve arises from the posterior end of the 
brachial plexus, enters the axillary border of the Subscapularis and terminates in 
the Teres major. The latter muscle is sometimes supplied by a separate branch. 
The Third, Middle or Long Subscapular Nerve (n. thoracodorsalis} (Fig. 638), the 
largest of the three, arises from the posterior end of the brachial plexus and follows 
the course of the subscapular artery, along the posterior wall of the axilla to the 
Latissimus dorsi muscle, through which it may be traced as far as its lower border. 
The Circumflex Nerve (n. axillaris} (Figs. 639 and 645).-The circumflex nerve 
supplies some of the muscles, the shoulder-joint, and the integument of the shoulder 
(Figs. 640 and 641), It arises from the posterior cord of the brachial plexus, in 
common with the musculo-spiral nerve, and its fibres may be traced through the 
posterior cord to the fifth and sixth cervical nerves. It is at first placed behind the 
axillary artery, between it and the Subscapularis muscle, and passes downward THE BRACHIAL PLEXUS 
985 
and outward to the lower border of that muscle. It then winds backward in com- 
pany with the posterior circumflex artery, through a quadrilateral space bounded 
above by the Teres minor muscle, below by the Teres major muscle, internally 
by the long head of the Triceps muscle, and externally by the neck of the humerus. 
The nerve then divides into two branches. 
The Upper Branch (Fig. 645) winds backward around the surgical neck of the 
humerus, beneath the Deltoid, with the posterior circumflex vessels, as far as the 
anterior border of that muscle, supplying it, and giving off cutaneous branches, 
which pierce the muscle and ramify in the integument covering its lower part 
(Fig. 642). 
The Lower Branch (Fig. 645), at its origin, distributes filaments to the Teres 
minor and back part of the Deltoid muscles. Upon the filaments to the former 
muscle an oval enlargement usually exists. The nerve then pierces the deep 
fascia, ami supplies the integument over the lower two-thirds of the posterior 
surface of the Deltoid (n. cutaneus brachii lateralis), as well as that covering 
the long head of the Triceps (caput longum n. tricipitis brachii) (Fig. 643). 
The circumflex nerve, before its division, gives off an articular filament, which 
enters the shoulder-joint below the Subscapularis muscle. 
The Musculo-cutaneous or the External Cutaneous Nerve or the Perforating Nerve 
of Casserius1 (n. musculocutaneus) (Figs. 638, 639, and 644).-The musculo- 
cutaneous, or the external cutaneous nerve, supplies some of the muscles of the 
arm and the integument of the forearm. It arises from the outer cord of the 
brachial plexus, opposite the lower border of the Pectoralis minor muscle, 
receiving filaments from the fifth, sixth, and seventh cervical nerves. It per- 
forates the Coraco-brachialis muscle (Fig. 644), passes obliquely between the Biceps 
and Brachialis anticus muscles to the outer side of the arm, and, a little above 
the elbow, winds around the outer border of the tendon of the Biceps, and, per- 
forating the deep fascia, becomes cutaneous (Fig. 640). This nerve, in its course 
through the arm, supplies the Coraco-brachialis, Biceps, and the greater part 
of the Brachialis anticus muscles. The branch to the Coraco-brachialis is given 
off from the nerve close to its origin, and in some instances, as a separate fila- 
ment from the outer cord of the plexus. The branches to the Biceps and 
Brachialis anticus are given off after the nerve has pierced the Coraco-brachialis. 
The nerve also sends a small branch to the humerus, which enters the nutrient 
foramen with the accompanying artery, and a filament, from the branch supplying 
the Brachialis anticus, goes to the elbow-joint. The musculo-cutaneous furnishes 
the chief nerve supply to this joint. 
The Cutaneous Portion of the Musculo-cutaneous Nerve (n. cutaneus antibrachii 
lateralis) passes behind the median cephalic vein, and divides, opposite the 
elbow-joint, into an anterior anti a posterior branch. 
The anterior branch descends along the radial border of the forearm to the 
wrist, and supplies the integument over the outer half of the anterior surface. At 
the wrist-joint it is placed in front of the radial artery, and some filaments, piercing 
the deep fascia, accompany that vessel to the back of the wrist, supplying the 
carpus. The nerve then passes downward to the ball of the thumb, where it 
terminates in dutaneous filaments. It communicates with a branch from the radial 
nerve and with the palmar cutaneous branch of the median. 
The posterior branch passes downward along the back part of the radial side 
of the forearm to the wrist. It supplies the integument of the lower third of the 
forearm, communicating with the radial nerve and the external cutaneous branch 
of the musculo-spiral. The cutaneous areas supplied by the musculo-cutaneous 
nerve are indicated in Figs. 642 and 643. 
The musculo-cutaneous nerve presents frequent irregularities. It may adhere 
1 See foot-note, page 1027. 986 
THE NERVOUS SYSTEM 
for some distance to the median and then pass outward, beneath the Biceps, 
instead of through the Coraco-brachialis. Frequently some of the fibres of the 
median run for some distance in the musculo-cutaneous and then leave it to join 
their proper trunk. Less frequently the reverse is the case, and the median sends 
a branch to join the musculo-cutaneous. Instead of piercing the Coraco-brachialis 
muscle the nerve may pass under it or through the Biceps. Occasionally it gives a 
filament to the Pronator radii teres muscle, and it has been seen to supply the 
back of the thumb when the radial nerve was absent. 
The Internal Cutaneous Nerve (n. cutaneus antibrachii medians') (Figs. 638, 639, 
and 644).-The internal cutaneous nerve is one of the smallest branches of 
the brachial plexus. It arises from the inner cord in common with the ulnar 
nerve and internal head of the median nerve, and, at its commencement, is 
placed on the inner side of the axillary artery, and afterward of the brachial 
artery. It derives its fibres from the eighth cervical and first dorsal nerves. 
It passes down the inner side of the arm, pierces the deep fascia with the 
basilic vein, about the middle of the limb, and, becoming cutaneous, divides into 
two branches, anterior and posterior. 
This nerve gives off, near the axilla, a cutaneous filament, which pierces the fascia 
and supplies the integument covering the Biceps muscle nearly as far as the elbow. 
This filament lies a little external to the common trunk, from which it arises. 
The anterior branch, the larger of the two, passes usually in front of, but occa- 
sionally behind, the median basilic vein. It then descends on the anterior surface 
of the ulnar side of the forearm, distributing filaments to the integument as far 
as the wrist, and communicating with a cutaneous branch of the ulnar nerve 
(Fig. 640). 
The posterior branch passes obliquely downward on the inner side of the basilic 
vein, passes in front of, or over, the internal condyle of the humerus to the back 
of the forearm, and descends on the posterior surface of its ulnar side as far as 
the wrist, distributing filaments to the integument (Fig. 641). It communicates, 
above the elbow, with the lesser internal cutaneous nerve, and above the wrist 
with the dorsal cutaneous branch of the ulnar nerve (Swan). The cutaneous areas 
supplied by the internal cutaneous nerve are indicated in Figs. 642 and 643. 
The Lesser Internal Cutaneous Nerve or the Nerve of Wrisberg (n. cutaneus 
brachii medialis) (Figs. 638, 639, and 644).-The lesser internal cutaneous nerve 
is distributed to the integument on the inner side of the arm. It is the smallest of 
the branches of the brachial plexus, and, arising from the inner cord, receives 
its fibres from the first dorsal nerve. It passes through the axillary space, at first 
lying behind, and then on the inner side of, the axillary vein, and communicates 
with the intercosto-humeral nerve. It descends along the inner side of the brachial 
artery to the middle of the arm, where it pierces the deep fascia, and is distributed 
to the integument of the back part of the lower third of the arm, extending as far 
as the elbow (Figs. 640, 641, and 642), where some filaments are lost in the integu- 
ment in front of the inner condyle, and others over the olecranon. It commu- 
nicates with the posterior branch of the internal cutaneous nerve. 
In some cases the nerve of Wrisberg and the intercosto-humeral nerve are 
connected by two or three filaments which form a plexus at the back part of 
the axilla. In other cases the intercosto-humeral is of large size, and takes the 
place of the nerve of Wrisberg, receiving merely a filament of communication from 
the brachial plexus, which filament represents the latter nerve. In other cases 
this filament is wanting, the place of the nerve of Wrisberg being supplied 
entirely by the intercosto-humeral. 
The Median Nerve (n.medianus) (Figs. 638,639, and644).-The median nerve has 
received its name from the course it takes along the middle of the arm and forearm 
to the hand, lying between the ulnar and musculo-spiral nerves, and the ulnar and THE BRACHIAL PLEXUS 
987 
the radial nerves. It arises by two roots, one from the outer, and one from the inner, 
cord of the brachial plexus; these embrace the lower part of the axillary artery, 
uniting either in front or on the outer side of that vessel. The median nerve 
receives filaments from the sixth, seventh, and eighth cervical and the first 
dorsal nerves. As it descends through the arm, it lies at first on the outer side 
of the brachial artery, crosses that vessel in the middle of its course, usually in 
front, but occasionally behind it, and lies on its inner side to the bend of the 
elbow, where it is placed beneath the bicipital fascia, and is separated from the 
elbow-joint by the Brachialis anticus muscle. In the forearm it passes between 
the two heads of the Pronor radii teres muscle, and descends beneath the Flexor 
sublimis muscle, lying on the Flexor profundus muscle, to within two inches 
above the annular ligament, where it becomes more superficial, lying between the 
tendons of the Flexor sublimis and Flexor carpi radialis muscles, beneath, and 
rather to the radial side or under the tendon of the Palmaris longus, covered by 
the integument and fascia. It then passes through the carpal canal (canalis carpi) 
beneath the annular ligament into the hand. In its course through the forearm 
it is accompanied by a branch of the anterior interosseous artery. 
Branches.-With the exception of the nerve to the Pronator radii teres muscle, 
which sometimes arises above the elbow-joint, and filaments to the elbow-joint, 
the median nerve gives off no branches in the arm. In the forearm its branches 
are muscular, anterior interosseous, and palmar cutaneous, and, according to 
Riidinger and Macalister, two articular twigs to the elbow-joint. 
The Muscular Branches (rami musculares) supply all the superficial muscles on 
the front of the forearm except the Flexor carpi ulnaris. These branches are 
derived from the nerve near the elbow. 
The Anterior Interosseous (n. interosseus [antibrachii] volaris) (Fig. 644) supplies 
the deep muscles on the front of the forearm, except the inner half of the Flexor 
profundus digitorum. It accompanies the anterior interosseous artery along the 
interosseous membrane, in the interval between the Flexor longus pollicis and 
Flexor profundus digitorum muscles, both of which it supplies, and terminates 
below in the Pronator quadratus muscle sending filaments to the inferior radio- 
ulnar articulation and the wrist-joint. 
The Palmar Cutaneous Branch (ramus cutaneus palmaris n. mediani) arises from 
the median nerve at the lower part of the forearm. It pierces the fascia above 
the annular ligament, and, descending over that ligament, divides into two 
branches; of which the outer branch supplies the skin over the ball of the thumb, 
and communicates with the anterior cutaneous branch of the musculo-cutaneous 
nerve; and the inner branch supplies the integument of the palm of the hand, 
communicating with the cutaneous branch of the ulnar. 
In the palm of the hand the median nerve is covered by the integument and 
palmar fascia and is crossed by the superficial palmar arch. It rests upon the 
tendons of the flexor muscles. In this situation it becomes enlarged, somewhat 
flattened, of a reddish color, and divides into two branches. Of these, the external 
branch supplies a muscular branch to some of the muscles of the thumb and 
digital branches to the thumb and index finger; the internal branch supplies digital 
branches to the contiguous sides of the index and middle and of the middle and 
ring fingers. The digital branches, before they subdivide, are called common 
palmar digital branches of the median nerve (nn. digitales volares communes). 
The branch to the muscles of the thumb (ramus muscularis) is a short nerve which 
divides to supply the Abductor, Opponens, and the superficial head of the Flexor 
brevis pollicis muscles, the remaining muscles of this group being supplied by 
the ulnar nerve. 
The Collateral Palmar Digital or the Digital Branches (nn. digitales volares proprii) 
are five in number. The first and second pass along the borders of the thumb, THE NERVOUS SYSTEM 
988 
the external branch communicating with branches of the radial nerve. The third 
passes along the radial side of the index finger, and supplies the First lumbricalis 
muscle. The fourth subdivides to supply the adjacent sides of the index and 
middle fingers, and sends a branch to the Second lumbricalis muscle. The fifth 
supplies the adjacent sides of the middle and ring fingers, and communicates with 
a branch from the ulnar nerve. 
Each digital nerve, opposite the base of the first phalanx, gives off a dorsal 
branch, which joins the dorsal digital nerve from the radial nerve and runs along 
the side of the dorsum of the finger, to end in the integument over the last phalanx. 
At the end of the finger the digital nerve divides into a palmar and a dorsal branch, 
the former of which supplies the extremity of the finger, and the latter ramifies 
around and beneath the nail. The digital nerves, as they run along the fingers, are 
placed superficial to the digital arteries. The cutaneous areas supplied by the 
median nerve are shown in Figs. 642 and 643. 
The Ulnar Nerve (n. ulnaris) (Figs. 638, 639, and 644).-The ulnar nerve is 
placed along the inner or ulnar side of the upper limb, and is distributed to the 
muscles and integument of the forearm and hand. It is smaller than the median, 
behind which it is placed, diverging from it in its course down the arm. It arises 
from the inner cord of the brachial plexus, in common with the inner head of the 
median and the internal cutaneous nerve, and derives its fibres from the eighth 
cervical and first dorsal nerves. At its commencement it lies to the inner side of 
the axillary artery, and holds the same relation with the brachial artery to the 
middle of the arm. From this point it runs obliquely across the internal head 
of the Triceps, pierces the internal intermuscular septum, and descends to the 
groove between the internal condyle and the olecranon, accompanied by the in- 
ferior profunda artery. At the elbow it rests upon the back of the inner condyle, 
and passes into the forearm between the two heads of the Flexor carpi ulnaris 
muscle. In the forearm it descends in a perfectly straight course along the ulnar 
side of the extremity, lying upon the Flexor profundus digitorum muscle, its 
upper half being covered by the Flexor carpi ulnaris muscle, its lower half lying 
on the outer side of the muscle, being covered by the integument and fascia. 
The ulnar artery, in the upper third of its course, is separated from the ulnar 
nerve by a considerable interval, but in the rest of its extent the nerve lies to 
its inner side. At the wrist the ulnar nerve crosses the annular ligament on the 
outer side of the pisiform bone, to the inner side of and a little behind the ulnar 
artery, and immediately beyond this bone divides into two branches, the 
superficial and the deep palmar. 
Branches.-The branches of the ulnar nerve are- 
Articular. 
Muscular. 
Cutaneous. 
Dorsal cutaneous. 
In the forearm 
In the hand 
Superficial palmar. 
Deep palmar. 
The Articular Branches distributed to the elbow-joint consist of several small 
filaments. They arise from the nerve as it lies in the groove between the inner 
condyle of the humerus and the olecranon process of the ulnar. 
The Muscular Branches (rami musculares) are two in number-one supplying 
the Flexor carpi ulnaris; the other, the inner half of the Flexor profundus digi- 
torum. 'They arise from the trunk of the nerve near the elbow. 
The Cutaneous Branch arises from the ulnar nerve about the middle of the fore- 
arm, and divides into two branches. 
One branch (frequently absent) pierces the deep fascia near the wrist, and is 
distributed to the integument, communicating with a branch of the internal 
cutaneous nerve. 
The second branch, the palmar cutaneous (ramus cutaneus palmaris) lies on the THE BRACHIAL PLEXUS 
989 
ulnar artery, which it accompanies to the hand, some filaments entwining around 
the vessel; it ends in the integument of the palm, communicating with branches 
of the median nerve. 
The Dorsal Cutaneous Branch (ramus dorsalis manus) arises about two inches 
above the wrist; it passes backward beneath the Flexor carpi ulnaris muscle, 
perforates the deep fascia, and, running along the ulnar side of the back of the 
wrist and hand, divides into branches (nn. digitales dorsales)-, one of these sup- 
plies the inner side of the little finger; a second supplies the adjacent sides of 
the little and ring fingers; a third joins the branch of the radial nerve which 
supplies the adjoining sides of the middle and ring fingers, and assists in sup- 
plying these parts; a fourth is distributed to the metacarpal region of the hand, 
communicating with a branch of the radial nerve. 
On the little finger the dorsal digital branches extend only as far as the base 
of the terminal phalanx, and on the ring finger as far as the base of the second 
phalanx; the more distal parts of these digits are supplied by dorsal branches 
derived from the palmar digital branches of the ulnar. 
The Superficial Palmar Branch (ramus superficialis n. ulnaris) supplies the 
Palmaris brevis and the integument on the inner side of the hand, and terminates 
in two digital branches, which are distributed, one to the ulnar side of the little 
finger, the other to the adjoining sides of the little and ring fingers, the latter 
communicating with a branch from the median. The digital branches are dis- 
tributed to the fingers in the same manner as the digital branches of the median. 
Fhe Deep Palmar Branch (ramus profundus n. ulnaris), accompanied by the 
deep branch of the ulnar artery, passes between the Abductor and Flexor brevis 
minimi digiti muscles; it then perforates the Opponens minimi digiti and follows 
the course of the deep palmar arch beneath the flexor tendons. At its origin it 
supplies the muscles of the little finger. As it crosses the deep part of the hand 
it sends two branches to each interosseous space, one for the Dorsal and one for 
the Palmar interosseous muscle, the branches to the Second and Third palmar 
interossei supplying filaments to the two inner Lumbrical muscles. At its ter- 
mination between the thumb and index finger, it supplies the Adductores trans- 
versus et obliquus pollicis and the inner head of the Flexor brevis pollicis. It also 
sends articular filaments to the wrist-joint, and to the bones and joints of the hand. 
It will be remembered that the inner part of the Flexor profundus digitorum 
muscle is supplied by the ulnar nerve; the two inner Lumbricales, which are 
connected with the tendons of this part of the muscle, are therefore supplied by 
the same nerve. The outer part of the Flexor profundus is supplied by the 
median nerve; the two outer Lumbricales, which are connected with the tendons 
of this part of the muscles, are therefore supplied by the same nerve. Brooks 
states that in twelve instances out of twenty-one he found that the third lum- 
brical received a twig from the median nerve, in addition to its branch from the 
ulnar. The palmar branches of the ulnar which go to the fingers are called by 
Toldt before division common palmar digital branches, and after division collateral 
palmar digital branches. The cutaneous areas supplied by the ulnar nerve are 
shown in Figs. 642 and 643. 
The Musculo-spiral Nerve (n. radialis) (Figs. 639, 644, and 645).-The musculo- 
spiral nerve, the largest branch of the brachial plexus, supplies the muscles of the 
back part of the arm and forearm, and the integument of the same parts, as well as 
that of the back of the hand (Figs. 642 and 643). It arises from the posterior cord of 
the brachial plexus, of which it maybe regarded as the continuation. It receives fila- 
ments from the sixth, seventh, and eighth,and sometimes also from the fifth cervical 
nerves. At its commencement it is placed behind the axillary artery and the upper 
part of the brachial artery, passing down in front of the tendons of the Latissimus 
dorsi and Teres major muscles. It winds around the humerus in the musculo-spiral 990 
THE NERVOUS SYSTEM 
groove with the superior profunda artery, passing from the inner to the outer side 
of the bone, between the internal and external heads of the Triceps muscle (Fig. 
645). It pierces the external intermuscular septum, and descends between the 
Brachialis anticus and Supi- 
nator longus muscles to the 
front of the external condyle 
of the humerus, where it sends 
filaments to the elbow-joint 
and divides into the radial and 
posterior interosseous nerves. 
Branches.-The branches of 
the musculo-spiral nerve are- 
Muscular. 
Cutaneous. 
Radial. 
Posterior interosseous. 
The Muscular Branches (rami 
musculares n. radialis) are di- 
vided into internal, posterior, 
and external; they supply the 
Triceps, Anconeus, Supinator 
longus, Extensor carpi radialis 
longior, and Brachialis anticus 
muscles. These branches are 
derived from the nerve at the 
inner side, back part, and outer 
side of the arm. 
The internal muscular branches 
supply the inner and middle 
heads of the Triceps muscle. 
That to the inner head of the 
Triceps is a long, slender fila- 
ment which lies close to the 
ulnar nerve, as far as the lower 
third of the arm, and is there- 
fore frequently spoken of as the 
ulnar collateral branch. 
The posterior muscular branch, 
of large size, arises from the 
nerve in the groove between the 
Triceps muscle and the hu- 
merus. It divides into branches 
which supply the outer and in- 
ner heads of the Triceps and 
the Anconeus muscles. The 
branch for the latter muscle is 
a long, slender filament which 
descends in the substance of 
the Triceps to the Anconeus. 
The external muscular branches supply the Supinator longus, Extensor carpi 
radialis longior, and (usually) the outer part of the Brachialis anticus muscles. 
The Cutaneous Branches are three in number, one internal and two external, 
rhe internal cutaneous branch (n. cutaneus brachii posterior) arises in the axil- 
lary space with the inner muscular branch. It is of small size, and passes through 
Suprascapular. 
Circumflex. 
-Musculo-spiral. 
Posterior 
'interosseous. 
Fig. 645.-The suprascapular, circumflex, and musculo-spiral 
nerves. THE BRACHIAL PLEXUS 
991 
the axilla to the inner side of the arm, supplying the integument on its posterior 
aspeet nearly as far as the olecranon. In its course it crosses beneath the inter- 
costo-humeral nerve, with which it communicates. 
The external cutaneous branch (n. cutaneus antibrachii dorsalis) divides into two 
branches, and each one perforates the outer head of the Triceps muscle at its 
attachment to the humerus. The upper and smaller one passes to the front of the 
elbow, lying close to the cephalic vein, and supplies the integument of the lower half 
of the arm on its anterior aspect. The lower branch pierces the deep fascia below 
the insertion of the Deltoid muscle, and passes down along the outer side of the 
arm and elbow, and then along the back part of the radial side of the forearm to 
the wrist, supplying the integument in its course, and joining, near its termination, 
with the posterior cutaneous branch of the musculo-cutaneous nerve. 
The Radial Nerve (ramus superficialis n. radialis) (Fig. 644), passes along the front 
of the radial side of the forearm to the commencement of its lower third. It lies at 
first a little to the outer side of the radial artery, concealed beneath the Supinator 
longus muscle. In the middle third of the forearm it lies beneath the same 
muscle, in close relation with the outer side of the artery. It leaves the artery 
about three inches above the wrist, passes beneath the tendon of the Supinator 
longus muscle, and, piercing the deep fascia at the outer border of the forearm, 
divides into two branches. 
The external branch, the smaller of the two, supplies the integument of the 
radial side and ball of the thumb, joining with the anterior branch of the musculo- 
cutaneous nerve. 
The internal branch communicates, above the wrist, with the posterior cuta- 
neous branch from the musculo-cutaneous, and on the back of the hand forms an 
arch with the dorsal cutaneous branch of the ulnar nerve. It then divides into 
four digital nerves (nn. digitales dorsales), which are distributed as follows: The 
first supplies the ulnar side of the thumb; the second, the radial side of the index 
finger; the third, the adjoining sides of the index and middle fingers; and the 
fourth, the adjacent borders of the middle and ring fingers.1 The latter nerve 
communicates with a filament from the dorsal branch of the ulnar nerve. 
The Posterior Interosseous Nerve (ramus projundus n. radialis) (Figs. 644 and 
645).-The posterior interosseous nerve winds to the back of the forearm around 
the outer side of the radius, passes between the two planes of fibres of the Supinator 
brevis muscle, and is prolonged downward between the superficial and deep layer 
of muscles, to the middle of the forearm. Considerably diminished in size, it 
descends on the interosseous membrane, beneath the Extensor longus pollicis 
muscle, to the back of the carpus, where it presents a gangliform enlargement 
from which filaments are distributed to the inferior radio-ulnar articulation, to 
the wrist-joint, and to the ligaments and articulations of the carpus. It supplies all 
the muscles of the radial and posterior brachial regions, excepting the Anconeus, 
Supinator longus, and Extensor carpi radialis longior. 
Surgical Anatomy.-The brachial plexus may be ruptured by traction on the limb, leading 
to complete paralysis. Bristow2 has reported three cases of avulsion of the plexus and has 
described twenty-four cases. In these cases it is generally believed that the lesion is rather a 
tearing away of the nerves from the spinal cord than a solution of continuity of the nerve-fibres 
themselves. In a case operated upon by Bristow it was found that the plexus had given way 
where the four cervical nerves and the first dorsal nerve unite to form three trunks. In supraclavic- 
ular division of the brachial plexus, not only will there be motor and sensory paralysis in the limb, 
but the Serratus magnus muscle will probably be paralyzed, because of injury to the posterior 
thoracic nerve. In the axilla any of the nerves forming the brachial plexus may be injured by a 
wound of this part, the median being the one which is most frequently damaged from its exposed 
1 According to Hutchinson, the digital nerve to the thumb reaches only as high as the root of the nail; the 
one to the forefinger as high as the middle of the second phalanx, and the one to the middle and ring fingers not 
higher than the first phalangeal joint (London Hospital Gazette, vol. iii. p. 319).-Ed. of 15th English edition. 
- Annals of Surgery, September, 1902. 992 
THE NERVOUS SYSTEM 
position. The musculo-spiral, on account of its sheltered and deep position, is least often 
wounded. The brachial plexus in the axilla is often damaged from the pressure of a crutch, pro- 
ducing the condition known as crutch paralysis. In these cases the musculo-spiral is the nerve most 
frequently implicated; the ulnar nerve being the one that appears to suffer next infrequency. 
The circumflex nerve is of particular surgical interest. On account of its course around the 
surgical neck of the humerus, it is liable to be torn in fractures of this part of the bone, and 
in dislocations of the shoulder-foint, leading to paralysis of the deltoid, and, according to Erb, 
inflammation of the shoulder-joint is liable to be followed by a neuritis of this nerve from extension 
of the inflammation to it. 
Mr. Hilton takes the circumflex nerve as an illustration of a law which he lays down, that 
"the same trunks of nerves whose branches supply the groups of muscles moving a joint furnish 
also a distribution of nerves to the skin over the insertions of the same muscles, and the interior 
of the joint receives its nerves from the same source." In this way he explains the fact that an 
inflamed joint becomes rigid, because the same nerves which supply the interior of the joint 
supply the muscles which move that joint. 
The median nerve is liable to injury in wounds of the forearm. When paralyzed, there is 
loss of flexion of the second phalanges of all the fingers and of the terminal phalanges of the 
index and middle fingers. Flexion of the terminal phalanges of the ring and middle fingers can 
still be effected by that portion of the Flexor profundus digitormn which is supplied by the ulnar 
nerve. There is power to flex the proximal phalanges through the Interossei. The thumb 
cannot be flexed or opposed, and is maintained in a position of extension and adduction. All 
power of pronation is lost. The wrist can be flexed, if the hand is first adducted, by the action 
of the Flexor carpi ulnaris. There is loss or impairment of sensation on the palmar surface 
of the thumb, index, middle, and outer half of the ring fingers, and on the dorsal surface of the 
same fingers over the last two phalanges; except in the thumb, where the loss of sensation is 
limited to the back of the last phalanx. In order to expose the median nerve for the purpose 
of stretching it an incision should be made along the radial side of the tendon of the Palmaris 
longus muscle, which serves as a guide to the nerve. 
The ulnar nerve is liable to be injured in wounds of the forearm. When paralyzed, there 
is loss of power of flexion in the ring and little fingers; there is impaired power of ulnar 
flexion and adduction of the hand; there is inability to spread out the fingers from paralysis of 
the Interossei; and there is inability to adduct the thumb. The fingers cannot be flexed at the 
first joints, and cannoc be extended at the other joints. A claw-hand develops, the first pha- 
langes being overextended and the others flexed. Sensation is lost or impaired in the skin of the 
ulnar side of the hand anteriorly and posteriorly, involving the little finger, the ring finger, and 
the ulnar half of the middle finger posteriorly, and anteriorly involving the little finger and the 
ulnar half of the ring finger. In order to expose the nerve in the lower part of the forearm, 
an incision should be made along the outer border of the tendon of the Flexor carpi ulnaris, and 
the nerve will be found lying on the ulnar side of the ulnar artery. 
The musculo-spiral nerve is probably more frequently injured than any other nerve of the 
upper extremity. In consequence of its close relationship to the humerus as it lies in the 
musculo-spiral groove, it is frequently torn or injured in fractures of this bone, or subsequently 
involved in the callus that may be thrown out around a fracture, and thus pressed upon and its 
functions interfered with. It is also liable to be squeezed against the bone by kicks or blows and 
it may be divided by wounds of the arm. When paralyzed, the hand is flexed at the wrist 
and lies flaccid. This condition is known as drop-wrist. The fingers are also flexed, and on 
an attempt being made to extend them the last two phalanges only will be extended through the 
action of the Interossei, the first phalanges remaining flexed. There is no power of extending 
the wrist. Supination is completely lost when the forearm is extended on the arm, but is 
possible to a certain extent if the forearm is flexed so as to allow of the action of the Biceps. 
The power of extension of the forearm is lost on account of paralysis of the Triceps. Loss of 
sensation may be considerable or slight. Its area is shown in Fig. 643. The best position in 
which to expose the nerve for the purpose of stretching is to make an incision along the inner border 
of the Supinator longus muscle, just above the level of the elbow-joint The skin and superficial 
structures are to be divided and the deep fascia exposed. The white line in this structure indicat- 
ing the border of the muscle is to be defined, and the deep fascia divided in this line. By now raising 
the Supinator longus the nerve will be found lying beneath it, on the Brachialis anticus muscle. 
Post-anasthetic paralysis. When a person emerges from the influence of a general anaesthetic 
palsy of the arm may be found to exist. The brachial plexus may have been compressed during 
the operation by drawing the arm strongly from the body or elevating it by the side of the 
head. In such a case the plexus was compressed by the head of the humerus (Braun). 
The median nerve is stretched when the arm is rotated externally and drawn backward and 
outward. The ulnar nerve is stretched when the forearm is flexed and supinated (Braun). 
Garrigues believes that in most cases of post-ansesthetic paralysis the brachial plexus was squeezed 
between the collar bone and the first rib by the head of the patient being drawn to the opposite 
side or being allowed to fall back. ANTERIOR DIVISIONS OF THORACIC OR DORSAL NERVES 
993 
THE THORACIC OR DORSAL NERVES (NN. THORACALES.) 
The thoracic or dorsal nerves are twelve in number on each side. The first 
appears between the first and second dorsal vertebrae, and the last between the 
last dorsal and first lumbar. 
The Roots of the Thoracic or Dorsal Nerves. 
The roots of the thoracic or dorsal nerves are of small size, and vary but slightly 
from the second to the last. Both roots are very slender, the posterior roots 
slightly exceeding the anterior in thickness. They gradually increase in length 
from above downward, and in the lower part of the dorsal region pass down in 
contact with the spinal cord for a distance equal to the height of at least two ver- 
tebrae, before they emerge from the spinal canal. They then join in the inter- 
vertebral foramen, and at their exit divide into two primary divisions, a posterior 
(dorsal) and an anterior (intercostal). 
The Posterior Divisions of the Thoracic or Dorsal Nerves (Rami Posteriores) 
(Fig. 646). 
The posterior divisions of the thoracic or dorsal nerves are smaller than the 
anterior, pass backward between the transverse processes, and divide into interna! 
and external branches. 
Each internal branch is called a ramus medialis; each external branch is called 
a ramus lateralis. 
The Internal Branches.-The internal branches of the six upper nerves pass 
inward between the Semispinalis dorsi and Multifidus spinae muscles, which they 
supply, and then, piercing the origins of the Rhomboidei and Trapezius muscles, 
become cutaneous by the side of the spinous processes and ramify in the integu- 
ment. The internal branches of the six lower nerves are distributed to the 
Multifidus spinae, without giving off any cutaneous filaments. 
The External Branches.-The external branches increase in size from above 
downward. They pass through the Longissimus dorsi muscle to the cellular 
interval between it and the Iliocostalis muscle, and supply those muscles, as well 
as their continuations upward to the head, and also the Levatores costarum 
muscles; the five or six lower nerves also give off cutaneous filaments, which pierce 
the Serratus posticus inferior and Latissimus dorsi muscles in a line with the 
angles of the ribs, and then ramify in the integument. 
The Cutaneous Branches.-The cutaneous branches of the posterior primary 
divisions of the dorsal nerves are twelve in number. From each ramus medialis 
of the upper six nerves comes a ramus cutaneus medialis, and from each ramus 
lateralis of the lower six nerves comes a ramus cutaneus lateralis. The six upper 
cutaneous nerves are derived from the internal branches of the posterior divisions 
of the dorsal nerves. They pierce the origins of the Rhomboidei and Trapezius 
muscles, and become cutaneous by the side of the spinous processes, and then 
ramify in the integument. They are frequently furnished with gangliform enlarge- 
ments. The six lower cutaneous nerves are derived from the external branches 
of the posterior divisions of the dorsal nerves. They pierce the Serratus posticus 
inferior and Latissimus dorsi muscles in a line with the angles of the ribs, and 
then ramify in the integument. 
The Anterior Divisions of the Thoracic or Dorsal Nerves or the Intercostal 
Nerves (Rami Anteriores). 
The anterior divisions of the dorsal nerves or the intercostal nerves (nn. inter- 
costales) are twelve in number on each side. They are, for the most part, 994 
THE NERVOUS SYSTEM 
distributed to the parietes of the thorax and abdomen, separately from each 
other, without being joined in a plexus; in which respect they differ from the 
Fig. 646.-Superficial and deep distribution of the posterior divisions of the spinal nerves. (After Hirschfeld 
and LeveillS.) On the left side the cutaneous branches are represented lying on the superficial layer of muscles. 
On the right side the superficial muscles have been removed, the Splenius capitis and Complexus divided in the 
neck, and the Erector spinae divided and partly removed in the back, so as to expose the posterior divisions of 
the spinal nerves near their origin, a a. Lesser occipital nerve from the cervical plexus. 1. External muscular 
branches of the first cervical nerve, and union by a loop with the second. 2, placed on the Rectus capitis 
posticus major muscle, marks the great occipital nerve, passing round the short muscles and piercing the Com- 
plexus : the external branch is seen to the outside. 3. External branch from the posterior division of the third 
nerve. 3'. Its internal branch, sometimes called the third occipital. 4' to 8'. The internal branches of the 
several corresponding nerves on the left side. The external branches of these nerves, proceeding to muscles, 
are displayed on the right side, d 1 to d 6, and thence to d 12. External muscular branches of the posterior 
divisions of the twelve dorsal nerves on the right side, d 1' to d 6'. The internal cutaneous branches of the six 
upper dorsal nerves on the left side, d 7' to d 12'. Cutaneous twigs from the external branches of the six lower 
dorsal nerves. 11. External branches from the posterior divisions of several lumbar nerves on the right side, 
piercing the muscles, the lower descending over the gluteal region I' V. The same, more superficially, on the 
left side, s 8. The issue and union by loops of the posterior divisions of four sacral nerves on the right side 
s' s'. Some of those distributed to the skin on the left side. ANTERIOR DIVISIONS OF THORACIC OR DORSAL NERVES 
995 
other spinal nerves. Eaeh nerve is connected with the adjoining ganglion of the 
sympathetic by one or two filaments (ramus corn municans). The intercostal nerves 
may be divided into two sets, from the difference they present in their distribution. 
The six upper, with the exception of the first and the intercosto-humeral branch 
of the second, are limited in their distribution to the parietes of the chest. The 
six lower supply the parietes of the chest and abdomen, the last one sending a 
cutaneous filament to the buttock. 
The Anterior Division of the First Thoracic or First Dorsal Nerve.- 
The anterior division of the first dorsal nerve divides into two branches: one, the 
larger, leaves the thorax in front of the neck of the first rib, and enters into the 
formation of the brachial plexus; the other and smaller branch runs along the first 
intercostal space, forming the first intercostal nerve (n. intercostalis I), giving off 
muscular branches, and terminates on the front of the chest by forming the first 
anterior cutaneous nerve (ramus cutaneus anterior n. intercostalis I) of the thorax. 
Occasionally this anterior cutaneous branch is wanting. The first intercostal 
nerve, as a rule, gives off no lateral cutaneous branch, but sometimes a small 
branch is given off which communicates with the intercosto-humeral. It frequently 
receives a connecting twig from the second dorsal nerve, which passes upward 
over the neck of the second rib. 
The Anterior Divisions of the Upper Thoracic or Dorsal Nerves (nn. 
inter co st ales) (Fig. 646).-The anterior divisions of the second, third, fourth, fifth, 
and sixth dorsal nerves and the small branch from the first dorsal are confined to 
the parietes of the thorax, and are named upper or pectoral intercostal nerves. 
They pass forward in the intercostal spaces with the intercostal vessels, being 
situated below them. At the back of the chest they lie between the pleura and 
the External intercostal muscle, but are soon placed between the two planes cf 
Intercostal muscles as far as the middle of the rib. They then enter the sub- 
stance of the Internal intercostal muscles, and, running amidst their fibres as far 
as the costal cartilages, they gain the inner surface of the muscles and lie 
between them and the pleura. Near the sternum, they cross in front of the internal 
mammary artery and Triangularis sterni muscle, pierce the Internal intercostal 
muscles, the anterior intercostal membrane, and Pectoralis major muscle, and 
supply the integument of the front of the chest and over the mammary gland, 
forming the anterior cutaneous nerves of the thorax; the branch from the second 
nerve is joined with the supraclavicular nerves of the cervical plexus. 
Branches.-Numerous slender muscular filaments (rami musculares) supply the 
Intercostals, the Infracostales, the Levatores costarum, Serratus posticus superior, 
and Triangularis sterni muscles. Some of these branches, at the front of the chest, 
cross the costal cartilages from one to another intercostal space. 
Lateral Cutaneous Nerves of the Thorax (rami cutanei laterales [perforates]) (Fig. 
638).-These are derived from the intercostal nerves, midway between the vertebrae 
and sternum; they pierce the External intercostal and Serratus magnus muscles, 
and divide into two branches, anterior and posterior. 
The Anterior Branches (rami anteriores) are reflected forward to the side and the 
forepart of the chest, supplying the integument of the chest and mamma; those 
of the fifth and sixth nerves supply the upper digitations of the External oblique 
muscle. 
The Posterior Branches (rami posteriores) are reflected backward to supply the 
integument over the scapula and over the Latissimus dorsi muscle. 
The Lateral Cutaneous Branch of the Second Intercostal Nerve (n. intercosto- 
brachialis) is of large size, and does not divide, like the other nerves, into an 
anterior and posterior branch. It may unite with a branch of the third intercostal. 
The single nerve or the united nerve is named, from its origin and distribution, the 
intercosto-humeral nerve (Figs. 638 and 644). It pierces the External intercostal THE NERVOUS SYSTEM 
996 
muscle, crosses the axilla to the inner side of the arm, and joins with a filament from 
the nerve of Wrisberg. It then pierces the fascia, and supplies the skin of the upper 
half of the inner and back part of the arm (Figs. 642 and 643), communicating 
with the internal cutaneous branch of the musculo-spiral nerve. The size of this 
nerve is in inverse proportion to the size of the other cutaneous nerves, especially 
the nerve of Wrisberg. A second intercosto-humeral nerve is frequently given off 
from the third intercostal. It supplies filaments to the armpit and inner side of 
the arm. It may or may not send a branch to the intercosto-humeral. 
The Anterior Divisions of the Lower Thoracic or Dorsal Nerves.-The 
anterior divisions of the seventh, eighth, ninth, tenth, and eleventh dorsal nerves 
are continued anteriorly from the intercostal spaces into the abdominal wall, and 
the twelfth dorsal is continued throughout its whole course in the abdominal wall, 
since it is placed below the last rib; hence these nerves are named lower or abdom- 
inal intercostal nerves. They have (with the exception of the last) the same arrange- 
ment as the upper ones as far as the anterior extremities of the intercostal spaces, 
where they pass behind the costal cartilages, and between the Internal oblique and 
Transversalis muscles, to the sheath of the Rectus, which they perforate. They 
supply the Rectus muscle, and terminate in branches which become subcutaneous 
near the linea alba. These branches are named the anterior cutaneous nerves of 
the abdomen. They are directed outward as far as the lateral cutaneous nerves, 
supplying the integument of the front of the belly. The lower intercostal nerves 
supply the Intercostals, Serratus posticus inferior, and Abdominal muscles, and, 
about the middle of their course, give off lateral cutaneous branches which pierce 
the External intercostal and External oblique muscles, in the same line as the 
lateral cutaneous nerves of the thorax, and divide into anterior and posterior 
branches, which are distributed to the integument of the abdomen and back; the 
anterior branches supply the digitations of the External oblique muscle and extend 
downward and forward nearly as far as the margin of the Rectus muscle; the 
posterior branches pass backward to supply the skin over the Latissimus dorsi 
muscle. 
The Last Thoracic or Dorsal Nerve.-The last dorsal is larger than the other 
dorsal nerves. Its anterior division runs along the lower border of the last rib, 
and passes under the external arcuate ligament of the Diaphragm. It then runs 
in front of the Quadratus lumborum muscle, perforates the Transversalis muscle, 
and passes forward between it and the Internal oblique muscle, to be distributed 
in the same manner as the lower intercostal nerves. It communicates with the 
ilio-hypogastric branch of the lumbar plexus, and is frequently connected with 
the first lumbar nerve by a slender branch, the dorsi-lumbar nerve, which descends 
in the substance of the Quadratus lumborum muscle. It gives a branch to the 
Pyramidalis muscle. 
The Cutaneous Branches.-There are two cutaneous branches, an anterior and 
a lateral. 
The Anterior Cutaneous Branch is a terminal branch and is a direct prolongation 
from the intercostal. It supplies an area of skin of the abdominal wall between 
the umbilicus and pubis. 
The Lateral Cutaneous Branch (ramus cutaneus lateralis [abdominalis] inter- 
costal is XII) is remarkable for its large size; it perforates the Internal and Exter- 
nal oblique muscles, passes downward over the crest of the ilium in front of the 
iliac branch of the ilio-hypogastric, and is distributed to the integument of the 
front part of the gluteal region, some of its filaments extending as low down as 
the trochanter major. It does not divide into an anterior and a posterior branch, 
like the other lateral cutaneous branches of the intercostal nerves. 
Surgical Anatomy.-The lower seven intercostal nerves and the ilio-hypogastric from the 
first lumbar nerve supply the skin of the abdominal wall. They run downward and inward POSTERIOR DIVISIONS OF THE LUMBAR NERVES 
997 
fairly equidistant from each other. The sixth and seventh supply the skin over the "pit of the 
stomach;" the eighth corresponds to about the position of the middle linea transversa; the 
tenth to the umbilicus; and the ilio-hypogastric supplies the skin over the pubes and external 
abdominal ring. There are several points of surgical significance about the distribution of these 
nerves, and it is important to remember their origin and course, for in many diseases affecting 
the nerve-trunks at or near their origin the pain is referred to their peripheral terminations. Thus 
in Pott's disease of the spine children will often be brought to the surgeon suffering from pain 
in the belly. This is due to the fact that the nerves are irritated at the seat of disease as they 
issue from the spinal canal. When thfe irritation is confined to a single pair of nerves, the sen- 
sation complained of is often a feeling of constriction, as if a cord were tied around the abdomen; 
and in these cases the situation of the sense of constriction may serve to localize the disease in 
the spinal column. In other cases, where the bone disease is more extensive and two or more 
nerves are involved, a more diffused pain in the abdomen is complained of. A similar conditon 
is sometimes present in affections of the cord itself, as in tabes dorsalis. 
Again, it must be borne in njind that the same nerves which supply the skin of the abdomen 
supply also the muscles which constitute the greater part of the abdominal wall. Hence, it follows 
that any irritation applied to the peripheral terminations of the cutaneous branches in the 
skin of the abdomen is immediately followed by reflex contraction of the abdominal muscles. 
A good practical illustration of this may sometimes be seen in watching two surgeons examine 
the abdomen of the same patient. One, whose hand is cold, causes the muscles of the abdom- 
inal wall to at once contract and the belly to become rigid, and thus not nearly so suitable 
for examination; the other, who has taken the precaution to warm his hand, examines the 
abdomen without exciting any reflex contraction. The supply of both muscles and skin from 
the same source is of importance in protecting the abdominal viscera from injury. A blow 
on the abdomen, even of a severe character, will do no injury to the viscera if the muscles are 
in a condition of firm contraction; whereas in cases where the muscles have been taken unawares, 
and the blow has been struck while they were in a state of rest, an injury insufficient to produce 
any lesion of the abdominal wall has been attended with rupture of some of the abdominal con- 
tents. The importance, therefore, of immediate reflex contraction upon the receipt of an injury 
cannot be overestimated, and the intimate association of the cutaneous and muscular fibres in 
the same nerve produces a much more immediate response on the part of the muscles to any 
peripheral stimulation of the cutaneous filaments than would be the case if the two sets of fibres 
were derived from independent sources. 
Again, the nerves supplying the abdominal muscles and skin are derived from the lower inter- 
costal nerves and are intimately connected with the sympathetic supplying the abdominal viscera 
through the lower thoracic ganglia from which the splanchnic nerves are derived. In conse- 
quence of this, in rupture of the abdominal viscera and in acute peritonitis the muscles of the 
belly-wall become firmly contracted, and thus as far as possible preserve the abdominal contents 
in a condition of rest. 
THE LUMBAR NERVES (NN. LUMBALES). 
The lumbar nerves are five in number on each side. The first lumbar nerve 
appears between the first and second lumbar vertebrae, and the last between the 
last lumbar vertebra and the base of the sacrum. 
The Roots of the Lumbar Nerves. 
The roots of the lumbar nerves are the largest, and their filaments the most 
numerous, of all the spinal nerves, and they are closely aggregated together upon 
the lower end of the cord. The anterior roots are the smaller, but there is not the 
same disproportion between them and the posterior roots as in the cervical nerves. 
The roots of these nerves have a vertical direction, and are of considerable length, 
more especially the lower ones, since the spinal cord does not extend beyond the 
first lumbar vertebra. The roots become joined in the intervertebral foramina, and 
the nerves so formed divide at their exit into two divisions, posterior and anterior. 
The Posterior Divisions of the Lumbar Nerves (Rami Posteriores) (Fig. 646). 
The posterior divisions of the lumbar nerves diminish in size from above down- 
ward; they pass backward between the transverse processes, and divide into 
internal and external branches. 998 
THE NERVOUS SYSTEM 
The Internal Branches (rami mediates).-The internal branches, the smaller, 
pass inward close to the articular processes of the vertebrae, and supply the 
Multifidus spinae and Interspinales muscles. 
The External Branches (rami laterales).-1The external branches supply the 
Erector spinae and Intertransverse muscles. From the three upper branches 
cutaneous nerves are derived which pierce the aponeurosis of the Latissimus dorsi 
muscle and descend over the back part of the crest of the ilium, to be distributed 
to the integument of the gluteal region, some of the filaments passing as far as the 
trochanter major (Fig. 652). 
The posterior division of the fifth lumbar nerve usually sends a branch which 
forms a loop with the posterior division of the first sacral nerve. 
The Anterior Divisions of the Lumbar Nerves (Rami Anteriores). 
The anterior divisions of the lumbar nerves increase in size from above down- 
ward. At their origin they communicate with the lumbar ganglia of the sym- 
pathetic by long, slender filaments, which accompany the lumbar arteries around 
the sides of the bodies of the vertebrae, beneath the Psoas muscle. The nerves pass 
obliquely outward behind the Psoas magnus or between its fasciculi, distributing 
filaments to it and the Quadratus lumborum. The anterior divisions of the five 
lumbar, five sacral, and first coccygeal nerve constitute the lumbo-sacral plexus 
(plexus lumbosacralis). This is subdivided into the lumbar plexus, the sacral 
plexus, and the pudendal plexus. The anterior divisions of the four upper nerves 
are connected together in this situation by anastomotic loops, and form the lumbar 
plexus. The anterior division of the fifth lumbar, joined with a branch from the 
fourth, descends across the base of the sacrum to join the anterior division of the 
first sacral nerve and assist in the formation of the sacral plexus. The cord result- 
ing from the union of the fifth lumbar and the branch from the fourth is called 
the lumbo-sacral cord (truncus lumbosacralis) (Figs. 648 and 655). 
The Lumbar Plexus (Plexus Lumbalis) (Figs. 647, 648). 
The lumbar plexus is formed by the loops of communication between the ante- 
rior divisions of the four upper lumbar nerves. The plexus is narrow above, and 
often connected with the last dorsal nerve by a slender branch, the dorsi-lumbar 
nerve. The plexus is broad below, where it is joined to the sacral plexus by the 
lumbo-sacral cord. The lumbar plexus is situated in the substance of the Psoas 
muscle near its posterior part, in front of the transverse processes of the lumbar 
vertebrae. 
The mode in which the plexus is arranged varies in different subjects. It differs 
from the brachial plexus in not forming an intricate interlacement, but the several 
nerves of distribution arise from one or more of the spinal nerves in the following 
manner: The first lumbar nerve receives a branch from the last dorsal, and gives 
off a larger branch, which subdivides into the ilio-hypogastric and ilio-inguinal 
nerves; the first lumbar also gives off a communicating branch which passes down 
to the second lumbar nerve, and a third branch which unites with a branch of the 
second lumbar, to form the genito-crural nerve. The second, third, and fourth 
lumbar nerves divide into anterior and posterior divisions. The anterior division 
of the second divides into two branches, one of which joins with the above- 
mentioned branch of the first nerve to form the genito-crural; the other unites 
with the anterior division of the third nerve, and a part of the anterior division 
of the fourth nerve to form the obturator nerve. The remainder of the anterior 
division of the fourth nerve passes down to communicate with the fifth lumbar 
nerve. The posterior divisions of the second and third nerves divide into two THE LUMBAR PLEXUS 
999 
branches, a smaller branch from each uniting to form the external cutaneous nerve, 
and a larger branch from each, which join with the whole of the posterior division 
of the fourth lumbar nerve to form the anterior crural. The accessory obturator, 
when it exists, is formed by the union of two small branches given off from the 
third and fourth nerves. 
From this arrangement it follows that the ilio-hypogastric and ilio-inguinal 
are derived entirely from the first lumbar nerve; the genito-crural from the first 
and second nerves; the external cutaneous from the second and third; the anterior 
crural and obturator by fibres derived from the second, third, and fourth; and the 
accessory obturator, when it exists, from the third and fourth. 
Branches (Figs. 647 and 648).-The branches of the lumbar plexus are-the 
Ilio-hypogastric. 
Ilio-inguinal. 
Genito-crural. 
External cutaneous. 
Obturator. 
Accessory obturator. 
Anterior crural. 
The Ilio-hypogastric Nerve (n. iliohypogastricus) (Figs. 647 and 648).-The 
ilio-hypogastric nerve arises from the first lumbar nerve. It emerges from the 
outer border of the Psoas muscle at its 
upper part, and crosses obliquely in front 
of the Quadratus lumborum to the crest 
of the ilium. It then perforates the Trans- 
versalis muscle at its posterior part near the 
crest of the ilium. It gives off muscular 
branches (rami musculares) to the abdom- 
inal wall, and divides between the trans- 
versalis and the Internal oblique into two 
cutaneous branches, iliac and hypogastric. 
The Iliac Branch (ramus cutaneus lateralis) 
pierces the Internal and External oblique 
muscles immediately above the crest of the 
ilium, and is distributed to the integument 
of the gluteal region, behind the lateral 
cutaneous branch of the last dorsal nerve 
(Figs. 652 and 656). The size of this nerve 
bears an inverse proportion to that of the 
cutaneous branch of the last dorsal nerve. 
The Hypogastric Branch (ramus cutaneus 
anterior) (Fig. 649) continues onward be- 
tween the Internal oblique and Trans- 
versalis muscles. It then pierces the In- 
ternal oblique, and becomes cutaneous by 
perforating the aponeurosis of the External 
oblique, about an inch above and a little to 
the outer side of the external abdominal 
ring, and is distributed to the integument of the hypogastric region. The ilio- 
hypogastric nerve communicates with the last dorsal and ilio-inguinal nerves. 
The Ilio-inguinal Nerve (n. ilioinguinalis) (Figs. 647, 648, and 649).-The ilio- 
inguinal nerve, smaller than the preceding, arises with it from the first lumbar 
nerve. It emerges from the outer border of the Psoas muscle just below the ilio- 
hypogastric nerve, and, passing obliquely across the Quadratus lumborum and 
Iliacus muscles, perforates the Transversalis near the forepart of the crest of the 
ilium, and communicates with the ilio-hypogastric nerve between that muscle 
and the Internal oblique. The nerve then pierces the Internal oblique, distribu- 
Fig. 647.-Plan of the lumbar plexus. 1000 
THE NERVOUS SYSTEM 
ting muscular branches (rami musculares) to it, and, accompanying the spermatic 
cord through the external abdominal ring, is distributed to the integument of the 
upper and inner part of the thigh, and to the scrotum in the male (nn. scrotales 
anteriores) (Fig. 651), and to the labium majus in the female (nn. labiates anteriores). 
The size of this nerve is in inverse proportion to that of the ilio-hypogastric. 
Occasionally it is very small, and ends by joining the ilio-hypogastric; in such 
cases a branch from the ilio-hypogastric takes the place of the ilio-inguinal, or 
the ilio-inguinal nerve may be altogether absent. 
The Genito-crural Nerve (n. genitojemor alts') (Figs. 647 and 648) arises from 
the first and second lumbar nerves. It passes obliquely through the substance 
Fig. 648.-The lumbar plexus and its branches. 
of the Psoas muscle, and emerges from its inner border at a level corresponding 
to the intervertebral substance between the third and fourth lumbar vertebrae; 
it then descends on the surface of the Psoas muscle, under cover of the peri- 
toneum, and divides into a genital and a crural branch. 
The Genital Branch (n. spermaticus externus) passes outward on the Psoas 
magnus, and pierces the fascia transversalis, or passes through the internal abdom- 
inal ring; in the male it then descends along the back part of the spermatic cord to 
the scrotum, and supplies the Cremaster muscle. In the female it accompanies 
the round ligament, and is lost upon it. 
The Crural Branch (n. lumboinguinalis) (Fig. 649) descends on the external iliac 
artery, sending a few filaments around it, and, passing beneath Poupart's ligament THE LUMBAR PLEXUS 
1001 
External 
cutaneous. 
Anterior crural. 
Middle 
cutaneous. 
Anterior division 
of obturator. 
. Internal 
cutaneous. 
Internal 
saphenous. 
Musculo- 
cutaneous. 
Anterior 
tibial. 
External 
saphenous. 
Anterior tibial. 
Fig. 649.-Cutaneous nerves of lower 
extremity. Front view. 
Fig. 650.-Nerves of the lower extremity. 
Front view. 1002 
THE NERVOUS SYSTEM 
to the thigh, enters the sheath of the femoral vessels, lying superficial and a little 
external to the femoral artery. It pierces the anterior layer of the sheath of the 
vessels, and, becoming superficial by passing through the fascia lata, it supplies the 
skin of the anterior aspect of the thigh as far as midway between the pelvis and 
DORSAL DIVI- 
SIONS OF 
SACRAL 
NERVES 
PERFORATI NG 
CUTANEOUS 
OF FOURTH 
SACRAL 
EXTERNAL SAPHENOUS I. II. S.- 
MUSCULOCUTANEOUS 
IV. V. L. I. S. 
ANTERIOR TIBIAL IV. V. L. I. S. 
INTERNAL PLANTAR IV. V. L. 
EXTERNAL PLANTAR*- 
INTERNAL 
CALCANEAN 
I. II. S. 
Fig. 651.-Areas of distribution of the cutaneous 
nerves of the front of the lower limb. (W. Keiller, 
after Testut, in Gerrish's Text-book of Anatomy.) 
Fig. 652.-Areas of distribution of the cutane- 
ous nerves of the back of the lower limb. (W. 
Keiller, after Testut, in Gerrish's Text-book of 
Anatomy.) 
knee (Fig. 651). On the front of the thigh it communicates with the outer branch 
of the middle cutaneous nerve, derived from the anterior crural. 
A few filaments from this nerve may be traced on to the femoral artery; they 
are derived from the nerve as it passes beneath Poupart's ligament. THE LUMBAR PLEXUS 
1003 
The External Cutaneous Nerve (n. cutaneus jemoris lateralis) (Figs. 647, 648, 
649, and 650).-The external cutaneous nerve arises from the second and third 
lumbar nerves. It emerges from the outer border of the Psoas muscle about its 
middle, and crosses the Iliacus muscle obliquely, toward the anterior superior 
spine of the ilium. It then passes under Poupart's ligament and over the Sartorius 
muscle into the thigh, where it divides into two branches, anterior and posterior. 
The Anterior Branch descends in an aponeurotic canal formed in the fascia lata, 
becomes superficial about four inches below Poupart's ligament, and divides into 
branches which are distributed to the integument along the anterior and outer 
part of the thigh, as far down as the knee (Fig. 651). This nerve occasionally com- 
municates with a branch of the long saphenous nerve in front of the knee-joint. 
The Posterior Branch pierces the fascia lata, and subdivides into branches which 
pass backward across the outer and posterior surface of the thigh, supplying the 
integument from the crest of the ilium as far as the middle of the thigh (Fig. 652). 
The Obturator Nerve (n. obturatorius) (Figs. 647, 648, and 650).-The obturator 
nerve supplies the Obturator externus and Adductor muscles of the thigh, the 
articulations of the hip and knee, and occasionally the integument of the thigh 
and leg. It arises by three branches-from the second, the third, and the fourth 
lumbar nerves. Of these, the branch from the third is the largest, while that 
from the second is often very small. It descends through the inner fibres of the 
Psoas muscle, and emerges from its inner border near the brim of the pelvis; it then 
runs along the lateral wall of the pelvis, above the obturator vessels, to the upper 
part of the obturator foramen, where it enters the thigh, and divides into an 
anterior and a posterior branch, separated by some of the fibres of the Obturator 
externus muscle, and lower down by the Adductor brevis muscle. 
The Anterior Branch (ramus anterior) (Fig. 650) passes down in front of the 
Adductor brevis, being covered by the Pectineus and Adductor longus, and at the 
lower border of the latter muscle communicates with the internal cutaneous and 
internal saphenous nerves, forming a kind of plexus. It then descends upon the 
femoral artery, upon which it is finally distributed. The nerve, near the obturator 
foramen, gives off an articular branch to the hip-joint. Behind the Pectineus it 
distributes muscular branches to the Adductor longus and Gracilis, and usually 
to the Adductor brevis, and in rare cases to the Pectineus, and receives a com- 
municating branch from the accessory obturator nerve. 
Occasionally the communicating branch to the internal cutaneous and internal 
saphenous nerves is continued down, as a cutaneous branch (ramus cutaneus), to the 
thigh and leg. When this is so, this occasional cutaneous branch emerges from 
beneath the lower border of the Adductor longus, descends along the posterior 
margin of the Sartorius to the inner side of the knee, where it pierces the deep 
fascia, communicates with the long saphenous nerve, and is distributed to the 
integument of the inner side of the leg as low down as its middle. When this 
communicating branch is small its place is supplied by the internal cutaneous 
nerve. 
The Posterior Branch (ramus posterior) pierces the Obturator externus, sending 
branches to supply it, and passes behind the Adductor brevis on the front of the 
Adductor magnus, where it divides into numerous muscular branches, which 
supply the Adductor magnus, and the Adductor brevis when the latter does not 
receive a branch from the anterior division of the nerve. One of the branches 
gives off a filament to the knee-joint. 
The Articular Branch for the Knee-joint is sometimes absent; it perforates the 
lower part of the Adductor magnus, and enters the popliteal space; it then descends 
upon the popliteal artery, as far as the back part of the knee-joint, where it per- 
forates the posterior ligament, and is distributed to the synovial membrane. It 
gives filaments to the popliteal artery in its course. THE NERVOUS SYSTEM 
1004 
The Accessory Obturator Nerve or the Accessory Anterior Crural Nerve of Winslow 
(n. obturator ius accessorius (Fig. 648).-The accessory obturator nerve is not con- 
stantly present. It is of small size, and arises by separate filaments from the 
third and fourth lumbar nerves. It descends along the inner border of the Psoas 
muscle, crosses the ascending ramus of the os pubis, and passes under the outer 
border of the Pectineus muscle, where it divides into numerous branches. One 
of these supplies the Pectineus, penetrating its under surface; another is dis- 
tributed to the hip-joint; while a third communicates with the anterior branch of 
the obturator nerve. When this nerve is absent the hip-joint receives two branches 
from the obturator nerve. Occasionally the articular branch is very small, and 
becomes lost in the capsule of the hip-joint. 
The Anterior Crural Nerve (n. femoralis) (Figs. 647, 648, and 650).-The anterior 
crural nerve is the largest branch of the lumbar plexus. It supplies muscular 
branches to the Iliacus, Pectineus, and all the muscles on the front of the thigh, 
excepting the Tensor fasciae femoris; cutaneous filaments to the front and inner 
side of the thigh, and to the leg and foot (Figs. 651 and 652); and articular 
branches to the hip and knee. It arises from the second, third, and fourth 
lumbar nerves. It descends through the fibres of the Psoas muscle, emerging 
from muscle at the lower part of its outer border, and passes down between it 
and the Iliacus muscle, and beneath Poupart's ligament, into the thigh, where 
it becomes somewhat flattened, and divides into an anterior and a posterior part. 
Under Poupart's ligament it is separated from the femoral artery by a portion of 
the Psoas muscle, and lies beneath the iliac fascia. 
Within the abdomen the anterior crural nerve gives off from its outer side some 
small muscular branches to the Iliacus, and a branch to the femoral artery which 
is distributed upon the upper part of that vessel. The origin of this branch varies; 
it occasionally arises higher than usual, or it may arise lower down in the thigh. 
External to the pelvis the following branches are given off: 
From the Anterior Division. 
Middle cutaneous. 
Internal cutaneous. 
Muscular. 
From the Posterior Division. 
Long saphenous. 
Muscular. 
Articular. 
The middle and internal cutaneous branches of the anterior crural nerve are 
the rami cutanei anteriores n. femoralis of the new nomenclature. 
The Middle Cutaneous Nerve (Figs. 649 and 650) pierces the fascia lata (generally 
the Sartorius muscle also) about three inches below Poupart's ligament, and 
divides into two branches (Fig. 649), which descend in immediate proximity along 
the forepart of the thigh, to supply the integument as low as the front of the knee 
(Fig. 651), where it communicates with the internal cutaneous nerve and the 
patellar branch of the internal saphenous nerve, to form the patellar plexus. In 
the upper part of the thigh the outer division of the middle cutaneous nerve com- 
municates with the crural branch of the genito-crural nerve. 
The Internal Cutaneous Nerve (Fig. 649) passes obliquely across the upper part 
of the sheath of the femoral artery, and divides in front or at the inner side of that 
vessel into two branches, anterior and posterior or internal. 
The anterior branch runs downward on the Sartorius, perforates the fascia lata 
at the lower third of the thigh, and divides into two branches, one of which sup- 
plies the integument as low down as the inner side of the knee; the other crosses 
to the outer side of the patella, communicating in its course with the nervus 
cutaneus patellae, a branch of the internal saphenous nerve. 
The posterior or internal branch descends along the inner border of the Sartorius 
muscle to the knee, where it pierces the fascia lata, communicates with the long 
saphenous nerve, and gives off several cutaneous branches. The nerve then THE LUMBAR PLEXUS 
1005 
passes down the inner side of the leg, to the integument of which it is distributed. 
This nerve, beneath the fascia lata, at the lower border of the Adductor longus, 
joins in a plexiform network by uniting with branches of the long saphenous and 
obturator nerves (Fig. 650). When the communicating branch from the obturator 
nerve is large and continued to the integument of the leg, the inner branch of the 
internal cutaneous is small and terminates at the plexus, occasionally giving off 
a few cutaneous filaments. 
The internal cutaneous nerve, before dividing, gives off a few filaments, which 
pierce the fascia lata, to supply the integument of the inner side of the thigh (Figs. 
651 and 652). One of these filaments passes through the saphenous opening; 
a second becomes subcutaneous about the middle of the thigh (Fig. 649)-; and a 
third pierces the fascia at its lower third (Fig. 649). 
The Muscular Branches of the Anterior Division (rami musculares}.-The nerve 
to the Pectineus is often duplicated; it arises from the anterior crural immediately 
below Poupart's ligament, and passes inward behind the femoral sheath to enter 
the anterior surface of the muscle. The nerve to the Sartorius arises in common 
with the middle cutaneous. 
The Long or Internal Saphenous Nerve (n. saphenus} (Figs. 649 and 650) is 
the largest of the cutaneous branches of the anterior crural. It approaches the 
femoral artery where this vessel passes beneath the Sartorius, and lies in front of it, 
beneath the aponeurotic covering of Hunter's canal, as far as the opening in the 
lower part of the Abductor magnus. It then leaves the artery, and descends 
vertically along the inner side of the knee, beneath the Sartorius muscle, pierces 
the fascia lata opposite the interval between the tendons of the Sartorius and 
Gracilis muscles, and becomes subcutaneous. The nerve then passes along the 
inner side of the leg (Fig. 649), accompanied by the internal saphenous vein, 
descends behind the internal border of the tibia, and, at the lower third of the leg 
divides into two branches: one continues its course along the margin of the tibia, 
terminating at the inner ankle; the other passes in front of the ankle, and is 
distributed to the integument along the inner side of the foot, as far as the great 
toe, communicating with the internal branch of the musculo-cutaneous nerve. 
The long saphenous nerve about the middle of the thigh gives off a communicating 
branch which joins the plexus formed by the obturator and internal cutaneous 
nerves. 
At the inner side of the knee it gives off a large patellar branch, the nervus 
cutaneus patellae (ramus infrapatellaris), which pierces the Sartorius and fascia 
lata, and is distributed to the integument in front of the patella. This nerve com- 
municates above the knee with the anterior branch of the internal cutaneous and 
with the middle cutaneous; below the knee, with other branches of the long 
saphenous; and on the outer side of the joint, with branches of the external cuta- 
neous nerve, forming a plexiform network, the patella plexus (plexus patellae}. 
The cutaneous nerve of the patella is occasionally small, and terminates by' join- 
ing the internal cutaneous, which supplies its place in front of the knee. 
Below the knee the branches of the long saphenous nerves are distributed to 
the integument of the front and inner side of the leg (Figs. 651 and 652), com- 
municating with the cutaneous branches from the internal cutaneous or from the 
obturator nerve. The nerve also sends filaments to the ankle-joint. 
The Muscular Branches of the Posterior Division.-The muscular branches of the 
posterior division supply the four parts of the Quadriceps extensor muscle. 
The branch to the Rectus muscle enters its under surface high up, sending off a 
small filament to the hip-joint. 
The branch to the Vastus externus muscle, of large size, follows the course of 
the descending branch of the external circumflex artery to the lower part of the 
muscle. It gives off an articular filament to the knee-joint. 1006 
THE NERVOUS SYSTEM 
The branch to the Vastus intemus muscle is a long branch which runs down on 
the outer side of the femoral vessels in company with the internal saphenous 
nerve for its upper part. It enters the muscle about its middle, and gives off a 
filament which can usually be traced downward on the surface of the muscle to 
the knee-joint. 
The branch to the Crureus muscle enters the* muscle on its anterior surface 
about the middle of the thigh, and sends a filament through the muscle to the 
Subcrureus and the knee-joint. 
The articular branch to the hip-joint is derived from the nerve to the Rectus 
muscle. 
The articular branches to the knee-joint are three in number. One, a long, slender 
filament, is derived from the nerve to the Vastus externus muscle; it penetrates the 
capsular ligament of the joint on its anterior aspect. Another is derived from 
the nerve to the Vastus intern us muscle. It can usually be traced downward 
on the surface of this muscle to near the joint; it then penetrates the muscle 
and accompanies the deep branch of the anastomotica magna artery, pierces the 
capsular ligament of the joint on its inner side, and supplies the synovial 
membrane. The third branch is derived from the nerve to the Crureus. 
THE SACRAL AND COCCYGEAL NERVES (NN. SACRALES ET COCCYGEUS). 
The sacral nerves are five in number on each side. The four upper ones pass 
from the sacral canal through the sacral foramina; the fifth through the foramen 
between the sacrum and coccyx. 
The Roots of the Upper Sacral Nerves. 
The roots of the upper sacral nerves are the largest of all the spinal nerves; 
while those of the lowest sacral and the coccygeal nerve are the smallest. They are 
longer than those of any of the other spinal nerves, on account of the spinal cord 
not extending beyond the first lumbar vertebra. From their great length, and the 
appearance they present in connection with their attachment to the spinal cord, 
the roots of origin of these nerves are called collectively the cauda equina. 
Each sacral and coccygeal nerve separates into two divisions, posterior and 
anterior. 
The Posterior Divisions of the Sacral Nerves (Rami Posteriores) (Fig. 653). 
The posterior divisions of the sacral nerves are small, diminish in size from 
above downward, and emerge, except the last, from the sacral canal by the posterior 
sacral foramina. 
The Upper Sacral Nerves.-Each of the three upper ones is covered, at its 
exit from the sacral canal, by the Multifidus spinae muscle, and divides into an 
internal branch (ramus medialis) and an external branch (ramus lateralis). 
The Internal Branches.-The internal branches are small, and supply the Mul- 
tifidus spinae muscle. 
The External Branches.-The external branches join with one another, and with 
the last lumbar and fourth sacral nerves, in the form of loops on the posterior 
surface of the sacrum, constituting the posterior sacral plexus. From these loops 
branches pass to the outer surface of the great sacro-sciatic ligament, where they 
form a second series of loops beneath the Gluteus maxim us muscle. Cutaneous 
branches from this second series of loops, usually two or three in number, pierce 
the Gluteus maximus muscle along a line drawn from the posterior superior spine THE ANTE RIOR DIVISIONS OE THE SACRAL NERVES 
1007 
of the ilium to the tip of the coccyx. They supply the integument over the 
posterior part of the gluteal region (Fig. 652). 
The Lower Sacral Nerves.-The posterior divisions of the two lower sacral 
nerves are situated below the Multifidus spinae muscle. They are of small size, 
and do not divide into internal and external branches, but join with each other, 
Fig. 653.-The posterior sacral nerves. 
and with the posterior division of the coccygeal nerve to form the posterior sacro- 
coccygeal nerve, which passes through the sacro-sciatic ligament, and forms loops 
on the back of the sacrum, filaments from which supply the Extensor coccygeus 
and the integument over the coccyx (Fig. 652). 
The Anterior Divisions of the Sacral Nerves (Rami Anteriores) (Fig. 655). 
The anterior divisions of the sacral nerves diminish in size from above down- 
ward. The four upper ones emerge from the anterior sacral foramina; the ante- 
rior division of the fifth, after emerging from the spinal canal through its terminal 
opening, curves forward between the sacrum and the coccyx. All the anterior sacral 
nerves at their exit from the sacral foramina communicate with the sacral ganglia of 
the sympathetic. The first nerve (Fig. 654), of large size, unites with the lumbo-sacral 
cord (truncus lumbosacral is), formed by the fifth lumbar, and a branch from the 
fourth lumbar (n. fur call's). The second (Fig. 654), equal in size to the preceding, 
and the third (n. bigeminus) (Fig. 654), about one-fourth the size of the second, 
unite with this trunk, and form, with a small fasciculus from the fourth, the sacral 
plexus, a visceral branch being given off from the third nerve to the bladder 
(Fig. 655). 
The Fourth Anterior Sacral Nerve sends a branch to join the sacral plexus. The 
remaining portion of the nerve divides into visceral and muscular branches, and a 
communicating filament descends to join the fifth sacral nerve. 1008 
THE NERVOUS SYSTEM 
The visceral branches are distributed to the viscera of the pelvis, communicating 
with the sympathetic nerve. These branches ascend upon the rectum and bladder, 
and in the female upon the vagina, communicating with branches of the sym- 
pathetic from the pelvic plexus. The visceral branches of the third and fourth 
sacral do not join the gangliated cord. 
The muscular branches are distributed to the Levator ani, Coccygeus, and 
Sphincter ani. The branch to the Sphincter ani pierces the Levator ani, so as to 
reach the ischio-rectal fossa, where it is found lying in front of the coccyx. Cuta- 
neous filaments arise from the latter branch, which supply the integument between 
the anus and coccyx. Another cutaneous branch is frequently given off from this 
Femoral artery.- 
Br. to 
COCCYGEUS. 
Br. to 
LEVATOR ANI. 
Br. to 
SPHINCTER ANI 
Coccygeal. 
Fig. 654.-Side view of pelvis, showing sacral nerves. 
nerve, though sometimes from the pudic (Schwalbe). It perforates the great 
sacro-sciatic ligament, and, winding around the lower border of the Gluteus 
maximus, supplies the skin over the lower and inner part of this muscle. 
The Fifth Anterior Sacral Nerve, after passing from the lower end of the sacral 
canal, curves forward through the fifth sacral foramen, formed between the lower 
part of the sacrum and the transverse process of the first piece of the coccyx. It 
pierces the Coccygeus muscle, and descends upon its anterior surface to near the 
tip of the coccyx, where it again perforates the muscle, to be distributed to the 
integument over the back part and side of the coccyx. This nerve communicates 
above with the fourth sacral and below with the coccygeal nerve, and supplies the 
Coccygeus muscle. 
The Posterior Division of the Coccygeal Nerve. 
The coccygeal nerve divides into its anterior and posterior divisions in the 
spinal canal. The posterior division is the smaller. It does not divide, hut THE SACRAL OR SCIATIC PLEXUS 
1009 
receives, as already mentioned, a communicating branch from the last sacral, 
and is lost in the integument over the back of the coccyx. 
The Anterior Division of the Coccygeal Nerve. 
The anterior division of the coccygeal nerve is a delicate filament which escapes 
at the termination of the sacral canal; it passes downward behind the rudimentary 
transverse process of the first piece of the coccyx, and curves forward through 
the notch between the first and second pieces, piercing the Coccygeus muscle, and 
descending on its anterior surface to near the tip of the coccyx, where it again 
pierces the muscle, to be distributed to the integument over the back part and side 
of the coccyx. It is joined by a branch from the fifth anterior sacral as it descends 
on the surface of the Coccygeus muscle. 
The Pudendal Plexus {plexus pudendus).-The pudendal plexus is formed by 
fibres obtained from the anterior divisions of the first three sacral nerves and by 
the anterior divisions of the two lower sacral nerves and the coccygeal nerve. It 
is, so to speak, interpolated in the sacral plexus and is considered as a portion of it. 
The Sacral or Sciatic Plexus (Plexus Sacralis) and the Pudic or Pudendal 
Plexus (Plexus Pudendalis) (Fig. 655). 
The sacral plexus is formed by the lumbo-sacral cord, the anterior divisions 
of the three upper sacral nerves and a branch from the fourth. The pudic or 
pudendal plexus is considered with the sacral plexus. It is usually composed of 
FOURTH LUMBAR 
FIFTH LUMBAR 
FIRST SACRAL 
SECOND SACRAL 
SUPERIOR 
GLUTEAL 
THIRD SACRAL 
INFERIOR 
GLUTEAL 
FOURTH SACRAL 
PERINEAL BR. TO SPHINCTER 
& LEVATOR ANI 
FIFTH SACRAL 
N.TO COCCYGEUS 
VISCERAL ' 
COCCYGEAL 
GREAT| 
SCIATIC 
Fig. 655.--Plan of sacral plexus with the pudendal plexus. (Gerrish.) 
the anterior divisions of the second, third, fourth, and fifth sacral nerves and the 
coccygeal nerve. It is irregular in composition. Prof. Cunningham says: "There 
is no distinct point of separation between the two plexuses. On the contrary, there 
is considerable overlapping, so that two and sometimes three of the principal nerves 
derived from the pudendal plexus have their origin in common with nerves of the 1010 
THE NERVOUS SYSTEM 
sacral plexus." The nerves of these two plexuses proceed in different directions: 
the upper ones obliquely downward and outward, the lower ones nearly horizontally 
outward, and they all unite into two cords; an upper and larger cord, which is formed 
by the lumbo-sacral cord with the first, second, and the greater part of the third 
sacral nerves; and a lower and smaller cord, formed by the remainder of the third, 
with a portion of the fourth sacral nerve. The upper cord is prolonged into the 
great sciatic nerve and the lower into the pudic. Frequently a small filament is 
given off from the second sacral nerve to join the lower cord. 
Each of the nerves which form the plexus joins the sympathetic by gray rami 
communicantes. White rami communicantes join the third sacral and sometimes 
also the second and fourth sacrals to the sympathetic. 
'Fhe sacro-pudendal plexus is triangular in form, its base corresponding with 
the exit of the nerves from the sacrum, its apex with the lower part of the great 
sacro-sciatic foramen. It rests upon the anterior surface of the Pyriformis, and is 
covered in front by the pelvic fascia, which separates it from the sciatic and pudic 
branches of the internal iliac artery and from the viscera of the pelvis. The sacral 
plexus proper sends branches to the lower extremity; the pudendal plexus proper 
is largely limited to supplying the perineum. 
Branches.-The branches of the sacro-pudendal plexus are divided into col- 
lateral and terminal branches. 
Muscular. 
Superior gluteal. 
Inferior gluteal. 
Small sciatic 
Perforating cutaneous. 
Collateral branches 
Terminal branches 
Pudic. 
Great sciatic. 
The Muscular Branches (rami musculares).-The muscular branches supply the 
Pyriformis, Obturator internus, the two Gemelli, and the Quadratus femoris. 
The branch to the Pyriformis muscle arises from the upper two sacral nerves 
before they enter the plexus; the branch to the Obturator internus muscle arises 
at the junction of the him bo-sacral and first sacral nerves; it passes out of the 
pelvis through the great sacro-sciatic foramen below the Pyriformis, crosses the 
spine of the ischium, and re-enters the pelvis through the lesser sacro-sciatic 
foramen to enter the inner surface of the Obturator internus; the branch to the 
Gemellus superior muscle arises in common with the nerve to the Obturator 
internus muscle; it enters the muscle at the upper part of its posterior surface; 
the small branch to the Gemellus inferior and Quadratus femoris muscles also 
arises from the upper part of the plexus; it passes through the great sacro-sciatic 
foramen below the Pyriformis, and courses down beneath the great sciatic nerve, 
the Gemelli and tendon of the Obturator internus, supplies the muscles on their 
deep or anterior surface and gives off an articular branch to the hip-joint. A second 
articular branch is occasionally derived from the upper part of the sacral plexus. 
The Superior Gluteal Nerve (n. glutaeus superior) (Figs. 655 and 657).-The 
superior gluteal nerve arises from the back part of the lumbo-sacral cord, with 
some filaments from the first sacral nerve; it passes from the pelvis through the 
great sacro-sciatic foramen above the Pyriformis muscle, accompanied by the 
gluteal vessels, and divides into a superior and an inferior branch. 
The Superior Branch follows the line of origin of the Gluteus minimus, and 
supplies the Gluteus medius muscle. 
The Inferior Branch crosses obliquely between the Gluteus minimus and medius, 
distributing filaments to both these muscles, and terminates in the Tensor fasciae 
femoris muscle, extending nearly to its lower end. THE SACRAL OR SCIATIC PLEXUS 
1011 
The Inferior Gluteal Nerve (n. glutaeus inferior) (Fig. 655).-The inferior gluteal 
nerve arises from the lumbo-sacral cord and first and second sacral nerves, and is 
intimately connected with the small sciatic at its origin. It passes out of the pelvis 
through the great sciatic notch, beneath the Pyriformis muscle, and, dividing into 
a number of branches, enters the Gluteus maximus muscle on its under surface. 
The Small Sciatic Nerve (n. cutaneus femoris posterior) (Figs. 655, 656, and 657). 
-The small sciatic nerve supplies the integument of the perineum and back part 
of the thigh and leg. It is usually formed by the union of two branches, which 
arise from the second and third nerves of the sacral plexus. It issues from the 
pelvis through the great sacro-sciatic foramen below the Pyriformis muscle, 
descends beneath the Gluteus maximus with the sciatic artery, and at the 
lower border of that muscle passes along the back part of the thigh, beneath the 
fascia lata and over the long head of the Biceps, to the lower part of the popliteal 
region, where it pierces the fascia and becomes cutaneous. It then accompanies 
the external saphenous vein to about the middle of the leg, its terminal filaments 
communicating with the external saphenous nerve. 
The Branches of the small sciatic nerve are all cutaneous, and are grouped as 
follows: gluteal, perineal, and femoral. 
The Gluteal Cutaneous Branches (nn. clunium inferiores [laterales]) consist of two 
or three ascending filaments, which turn upward around the lower border of the 
Gluteus maximus to supply the integument covering the lower and outer part 
of that muscle (Fig. 652). 
The Perineal Cutaneous Branches (rami perineales) are distributed to the skin 
at the upper and inner side of the thigh, on its posterior aspect. One branch, 
longer than the rest, the inferior pudendal or long scrotal nerve (Fig. 657), curves 
forward below the tuber ischii, pierces the fascia lata, and passes forward beneath 
the superficial fascia of the perineum to be distributed to the integument of the 
scrotum in the male (Fig. 652) and the labium in the female, communicating with 
the superficial perineal and inferior hemorrhoidal nerves. 
The Femoral Cutaneous Branches are numerous descending filaments, derived 
from both sides of the nerves, which are distributed to the back, inner, and outer 
sides of the thigh, to the skin covering the popliteal space, and to the upper part 
of the leg (Fig. 652). 
The Perforating Cutaneous Nerve (n. clunium inferior medialis) (Fig. 655).-The 
perforating cutaneous nerve usually arises from the second and third sacral 
nerves, and is of small size. It is continued backward through the great sacro- 
sciatic ligament, and, winding around the lower border of the Gluteus maximus, 
supplies the integument covering the inner and lower part of that muscle. 
The Pudic Nerve (n. pudendus) (Figs. 655 and 657).-The pudic nerve is the 
direct continuation of the lower cord of the sacral plexus, and derives its fibres 
from the third and fourth sacral nerves, and frequently from the second also. 
It leaves the pelvis through the great sacro-sciatic foramen, below the Pyriformis. 
It then crosses the spine of the ischium, and re-enters the pelvis through the 
lesser sacro-sciatic foramen. It accompanies the pudic vessels upward and for- 
ward along the outer wall of the ischio-rectal fossa, being contained in a sheath 
of the obturator fascia, termed Alcock's canal, and divides into two terminal 
branches, the perineal nerve and the dorsal nerve of the penis or clitoris. Before 
its division it gives off the inferior hemorrhoidal nerve. 
The Inferior Haemorrhoidal Nerve (n. haemorrhoidalis inferior) is occasionally 
derived separately from the sacral plexus. It passes across the ischio-rectal fossa, 
with its accompanying vessels, toward the lower end of the rectum, and is dis- 
tributed to the Sphincter ani externus and to the integument around the anus. 
Branches of this nerve communicate with the inferior pudendal and superficial 
perineal nerves at the forepart of the perineum. 1012 
THE NERVOUS SYSTEM 
Superior 
gluteal. 
Pudic. 
Nerve to 
obturator internus. 
Small sciatic. 
Inferior, 
pudendal. 
Descend in <i 
cutaneous. 
Internal 
popliteal. 
External 
-popliteal, or 
peroneal. 
External 
saphenous. 
Posterior 
tibial. 
Comm uni cans 
peronei. 
Plantar 
cutaneous. 
Fig. 656.-Cutaneous nerves of lower 
extremity. Posterior view. 
Fig. 657.-Nerves of the lower extremity.1 
Posterior view. 
1 N. B.-In this diagram the external saphenous and communicans peronei are not in their normal position. 
They have been displaced by the removal of the superficial muscles. THE SACRAL OR SCIATIC PLEXUS 
1013 
The Perineal Nerve (n. perinei), the inferior and larger of the two terminal 
branches of the pudic, is situated below the pudic artery. It accompanies the 
superficial perineal artery in the perineum, dividing into cutaneous and muscular 
branches. 
'rhe cutaneous branches (superficial perineal) are two in number, posterior and 
anterior. The posterior or external branch pierces the base of the triangular liga- 
ment of the urethra, and passes forward along the outer side of the urethral 
triangle in company with the superficial perineal artery; it is distributed to the 
skin of the scrotum (nn. scrotales poster lores). It communicates with the inferior 
haemorrhoidal, the inferior pudendal, and the other superficial perineal nerve. 
The anterior or internal branch also pierces the base of the triangular ligament, and 
passes forward nearer to the middle line, to be distributed to the inner and back 
part of the scrotum. Both these nerves supply the labia majora in the female. 
'rhe muscular branches are distributed to the Transversus perinaei, Accelerator 
urinae, Erector penis, and Compressor urethrae. A distant branch is given off 
from the nerve to the Accelerator urinae, which pierces this muscle, and supplies 
the corpus spongiosum, ending in the mucous membrane of the urethra. This 
is the nerve to the bulb. 
'rhe Dorsal Nerve of the Penis (n. dorsalis penis) is the deepest division of the 
pudic nerve; it accompanies the pudic artery along the ramus of the ischium; it 
then runs forward along the inner margin of the ramus of the os pubis, between 
the superficial and deep layers of the triangular ligament. Piercing the superficial 
layer it gives a branch to the corpus cavernosum, and passes forward, in company 
with the dorsal artery of the penis, between the layers of the suspensory ligament, 
on to the dorsum of the penis, along which it is carried as far as the glans, to which 
it is distributed. 
In the female the dorsal nerve is very small, and supplies the clitoris (n. dorsalis 
clitoridis). 
The Great Sciatic Nerve (n. ischiadicus) (Figs. 655 and 657).-The great sciatic 
nerve supplies nearly the whole of the integument of the leg, the muscles of the 
back of the thigh, and those of the leg and foot. It is the largest nervous cord in the 
body, measuring three-quarters of an inch in breadth, and is the direct continuation 
of the upper division of the sacral plexus. It passes out of the pelvis through the 
great sacro-sciatic foramen, below the Pyriformis muscle. It descends between 
the trochanter major and tuberosity of the ischium, along the back part of the 
thigh, to about its lower third, where it divides into two large branches, the internal 
and external popliteal nerves (Fig. 657). 
This division may take place at any point between the sacral plexus and the 
lower third of the thigh. When the division occurs at the plexus, the two nerves 
descend together side by side; or they may be separated, at their commencement, 
by the interposition of part or the whole of the Pyriformis muscle. As the nerve 
descends along the back of the thigh, it rests upon the posterior surface of the 
ischium, the nerve of the Quadratus femoris, and the External rotator muscles, in 
company with the small sciatic nerve and artery, being covered by the Gluteus 
maximus; lower down, it lies upon the Adductor magnus, and is covered by the 
long head of the Biceps. The great sciatic even when apparently a single nerve 
is really two nerves appearing as one. 
Branches.-Thebranchesof the nerve, before its division, are articular and muscular. 
'Phe Articular Branches (rami articulares) arise from the upper part of the nerve; 
they supply the hip-joint, perforating the posterior part of its fibrous capsule. 
These branches are sometimes derived from the sacral plexus. 
The Muscular Branches (rami musculares) are distributed to the flexors of the leg- 
viz., the Biceps, Semitendinosus, and Semimembranosus, and a branch goes to the 
Adductor magnus. 'These branches are given off beneath the Biceps muscle. 1014 
THE NERVOUS SYSTEM 
The Internal Popliteal or Tibial Nerve (n. tibialis) (Figs. 655 and 657), in reality, 
arises from the fourth and fifth lumbar nerves and the first three sacral nerves, and 
becomes a part of the trunk of the great sciatic in the buttock, to emerge from it 
again at the bifurcation of the sciatic. It is the larger of the two terminal branches 
of the great sciatic, descends along the back part of the thigh, through the middle of 
the popliteal space, to the lower part of the Popliteus muscle, where it passes with 
the artery beneath the arch of the Soleus and becomes the posterior tibial. It is over- 
lapped by the hamstring muscles above, and then becomes more superficial, and 
lies to the outer side of, and some distance from, the popliteal vessels; opposite 
the knee-joint it is in close relation with the vessels, and crosses to the inner side of 
the artery. Below, it is overlapped by the Gastrocnemius muscle. 
The branches of this nerve are-articular, muscular, and a cutaneous branch, the 
communicating tibial nerve. 
The articular branches (rami articulares), usually three in number, supply the 
knee-joint; two of these branches accompany the superior and inferior internal 
articular arteries, and a third, the azygos articular artery. 
The muscular branches (rami musculares), four or five in number, arise from the 
nerve as it lies between the two heads of the Gastrocnemius muscle; they supply 
that muscle, and the Plantaris, Soleus, and Popliteus. The filaments which 
supply the Popliteus turn around its lower border and are distributed to its deep 
surface. 
The tibial communicating nerve (n. cutaneus surae medialis) is the cutaneous 
branch. It descends between the two heads of the Gastrocnemius muscle, and 
about the middle of the back of the leg pierces the deep fascia, and joins the 
peroneal or fibular communicating nerve (ramus anastomoticus peronaeus) from the 
external popliteal nerve to form the external or short saphenous (n. suralis) (Fig. 
657). The external saphenous nerve, formed by the communicating branches of 
the internal and external popliteal nerves, passes downward and outward near 
the outer margin of the tendo Achillis, lying close to the external saphenous vein, 
to the interval between the external malleolus and the os calcis. It divides in 
two branches, the posteror of which breaks up into external calcaneal branches 
(rami calcanei laterales). The anterior branch (n. cutaneus dorsalis lateralis) winds 
around the outer malleolus, and is distributed to the integument along the outer 
side of the foot and little toe, communicating on the dorsum of the foot with the 
musculo-cutaneous nerve. In the leg its branches communicate with those of the 
small sciatic. The cutaneous area supplied by the external saphenous nerve is 
indicated in Figs. 651, 652, and 659. 
The Posterior Tibial Nerve (Fig. 657) is the terminal portion of the internal 
popliteal nerve. It commences at the lower border of the Popliteus muscle, and 
passes along the back part of the leg with the posterior tibial vessels to the interval 
between the inner malleolus and the heel, where it divides into the external and 
internal plantar nerves. It lies upon the deep muscles of the leg, and is covered in 
the upper part by the muscles of the calf, lower down by the skin and fascia. In 
the upper part of its course it lies to the inner side of the posterior tibial artery, but 
it soon crosses that vessel, and lies to its outer side as far as the ankle. In the lower 
third of the leg it is placed parallel with the inner margin of the tendo Achillis. 
'Phe branches of the posterior tibial nerve are muscular, internal calcaneal or 
calcaneo-plantar, and articular. 
'The muscular branches (rami musculares) arise either separately or by a common 
trunk from the upper part of the nerve. They supply the Soleus, Tibialis posticus, 
Flexor longus digitorum, and Flexor longus hallucis muscles; the branch to the 
latter muscle accompanying the peroneal artery. The branch to the Soleus enters 
its deep surface, while the branch which this muscle receives from the internal 
popliteal enters its superficial aspect. THE SACRAL OR SCIATIC PLEXUS 
1015 
Ihe internal calcaneal or calcaneo-plantar branches (ram? calcanei mediates) per- 
forate the internal annular ligament, and supply the integument of the heel and 
inner side of the foot (Fig. 659). 
The articular branch (ramus articularis ad articulationem talocruralem) is given 
off just above the bifurcation of the nerve and supplies the ankle-joint. 
The Internal Plantar Nerve (n. plantaris medialis) (Fig. 658), the larger of the 
two terminal branches of the posterior tibial, accompanies the internal plantar 
artery along the inner side of the foot. From its origin at the inner ankle it passes 
beneath the Abductor hallucis, and divides into the common plantar digital nerves 
(nn. digitales plantares communes), which pass forward between the Abductor 
hallucis and the Flexor brevis digitorum, divides opposite the bases of the meta- 
tarsal bones into four collateral plantar digital branches, and communicates with the 
external plantar nerve. 
In its course the internal plantar nerve gives off cutaneous branches, which pierce 
the plantar fascia and supply the integument of the sole of the foot (Fig. 659); muscu- 
lar branches, which supply the Abductor hallucis 
and Flexor brevis digitorum; articular branches, 
to the articulations of the tarsus and meta- 
tarsus; and four collateral plantar digital branches 
(nn. digitales plantares proprii). The three outer 
branches pass between the divisions of the 
plantar fascia in the clefts between the toes; the 
first (innermost) branch becomes cutaneous 
farther back between the Adductor hallucis 
Internal 
plantar.' 
External 
'plantar. 
Deep 
'branch. 
Fig. 658.-The plantar nerves. 
Fig. 659.-Areas of distribution of the cutaneous nerves of the 
sole. (W. Keiller, in Gerrish's Text-book of Anatomy.) 
and Flexor brevis digitorum. They are distributed in the following manner: 
The first supplies the inner border of the great toe, and sends a filament to the 
Flexor brevis hallucis muscle; the second bifurcates, to supply the adjacent sides 
of the great and second toes, sending a filament to the First lumbrical muscle; the 
third supplies the adjacent sides of the second and third toes; the fourth supplies 
the corresponding sides of the third and fourth toes, and receives a communicating 
branch from the external plantar nerve (Fig. 659). Each digital nerve gives off 
cutaneous and articular filaments; and opposite the last phalanx sends a dorsal 
branch, which supplies the structures around the nail, the continuation of the nerve THE NERVOUS SYSTEM 
1016 
being distributed to tlie ball of the toe. It will be observed that the distribution 
of these branches is precisely similar to that of the median nerve in the hand. 
The External Plantar Nerve (n. plantaris lateralis) (Fig. 658), the smaller of the 
two, completes the nervous supply to the structures of the sole of the foot (Fig. 659), 
being distributed to the little toe, and one-half of the fourth, as well as to most of the 
deep muscles, its distribution being similar to that of the ulnar in the hand. It 
passes obliquely forward with the external plantar artery to the outer side of the 
foot, lying between the Flexor brevis digitorum and Flexor accessorius, and in 
the interval between the former muscle and Abductor minimi digiti divides into a 
superficial and a deep branch. Before its division it supplies the Flexor accessorius 
and Abductor minimi digiti. 
The superficial branch (ramus superficialis) separates into two digital nerves. 
Before division they are called common plantar digital nerves (nn. digitales plantares 
communes), after division the collateral plantar digital nerves (nn. digitales plantares 
proprii): one, the external branch, the smaller of the two, supplies the outer side of 
the little toe, the Flexor brevis minimi digiti, and the two Interosseous muscles 
of the fourth metatarsal space; the other and larger digital branch supplies the 
adjoining sides of the fourth and fifth toes, and communicates with the internal 
plantar nerve. 
The deep or muscular branch (ramus profundus) accompanies the external 
plantar artery into the deep part of the sole of the foot, beneath the tendons of 
the Flexor muscles and Adductor obliquus hallucis, and supplies all the Interossei 
(except those in the fourth metatarsal space), the three outer Lumbricales, the 
Adductor obliquus hallucis, and the Adductor transversus hallucis. 
The External Popliteal or Peroneal Nerve (n. peronaeus communis) (Figs. 655 and 
657) in reality arises from the fourth and fifth lumbar and the first and second 
sacral nerves. It is about one-half the size of the internal popliteal, descends 
obliquely along the outer sides of the popliteal space to the head of the fibula, close 
to the inner margin of the Biceps muscle. It is easily felt beneath the skin behind 
the head of the fibula at the inner side of the tendon of the Biceps. It passes 
between the tendon of the Biceps and outer head of the Gastrocnemius muscle, 
winds around the neck of the fibula, between the Peroneus longus and the bone, 
and divides beneath the muscle into the anterior tibial and musculo-cutaneous nerves. 
The branches of the peroneal nerve, previous to its division, are articular and 
cutaneous. 
The articular branches (rami articvlares) are three in number: two of these 
accompany the superior and inferior external articular arteries to the outer side 
of the knee. The upper one occasionally arises from the great sciatic nerve before 
its bifurcation. The third (recurrent) articular nerve is given off at the point of 
division of the peroneal nerve; it ascends with the anterior recurrent tibial artery 
through the Tibialis anticus muscle to the front of the knee, which it supplies. 
The Sural or Lateral Cutaneous Branch (n. cutaneus surae lateralis).-There may 
be two or three of these branches. They supply the integument along the back 
part and outer side of the leg (Fig. 652). The largest cutaneous branch of the 
peroneal is the peroneal communicating (ramus anastomoticus peronaeus or commu- 
nicans fibularis), arises near the head of the fibula, crosses the external head of 
the Gastrocnemius to the middle of the leg, and joins with the communicans tibialis 
to form the external saphenous. This nerve occasionally exists as a separate branch, 
which is continued as far down as the heel. 
The Anterior Tibial Nerve (n. peronaeus profundus) (Fig. 650) commences at the 
bifurcation of the peroneal nerve, between the fibula and upper part of the Pero- 
neus longus muscle, passes obliquely forward beneath the Extensor longus digi- 
torum muscle to the forepart of the interosseous membrane, and gets into relation 
with the anterior tibial artery above the middle of the leg; it then descends with THE SACRAL OR SCIATIC PLEXUS 
1017 
the artery to the front of the ankle-joint, where it divides into an external and an 
internal branch. This nerve lies at first on the outer side of the anterior tibial artery, 
then in front of it, and again at its outer side at the ankle-joint. 
The branches of the anterior tibial nerve in its course through the leg are the 
muscular branches (rami musculares) to the Tibialis anticus, Extensor longus digi- 
torum, Peronaeus tertius, and Extensor proprius hallucis muscles, and an articular 
branch to the ankle-joint. 
The external or tarsal branch of the anterior tibial passes outward across the 
tarsus, beneath the Extensor brevis digitorum, and, having become enlarged, 
like the posterior interosseous nerve at the wrist, supplies the Extensor brevis 
digitorum muscle. From the enlargement three minute interosseous branches are 
given off which supply the tarsal joints and the metatarso-phalangeal joints of the 
second, third, and fourth toes. The first of these sends a filament to the second 
dorsal interosseous muscle. 
The internal branch, the continuation of the nerve, accompanies the dorsalis 
pedis artery along the inner side of the dorsum of the foot, and at the first inter- 
osseous space divides into two dorsal digital branches (nn. digitales dorsales hallucis 
lateralis et digiti secundi medians'), which supply the adjacent sides of the great 
and second toes (Fig. 651), communicating with the internal branch of the musculo- 
cutaneous nerve. Before it divides it gives off an interosseous branch to the first 
space, which supplies the metatarso-phalangeal joint of the great toe and sends a 
filament to the First dorsal interosseous muscle. 
The Musculo-cutaneous Nerve (n. peronaeus superficialis) (Fig. 650) supplies the 
muscles on the fibular side of the leg and the integument of the dorsum of the foot 
(Fig. 651). It passes forward between the Peronei muscles and the Extensor longus 
digitorum, pierces the deep fascia at the lower third of the leg on its front and outer 
side, and divides into two branches. This nerve in its course between the muscles 
gives off muscular branches (rami musculares) to the Peroneus longus and brevis, 
and cutaneous filaments to the integument of the lower part of the leg (Fig. 651). 
The internal branch (n. cutaneus dorsalis medialis) of the musculo-cutaneous 
nerve passes in front of the ankle-joint, and divides into two dorsal digital branches 
(nn. digitales dorsales pedis'), one of which supplies the inner side of the great toe, 
the other the adjacent sides of the second and third toes. It also supplies the 
integument of the inner ankle and inner side of the foot, communicating with 
the internal saphenous nerve, and joining with the anterior tibial nerve, between the 
great and second toes. 
"The external branch (n. cutaneus dorsalis intermedins), the smaller, passes along 
the outer side of the dorsum of the foot, and divides into two dorsal digital branches, 
the inner being distributed to the contiguous sides of the third and fourth toes, 
the outer to the opposed sides of the fourth and fifth toes. It also supplies the 
integument of the outer ankle and outer side of the foot, communicating with the 
short saphenous nerve. 
The branches of the musculo-cutaneous nerve supply all the toes excepting 
the outer side of the little toe, which is supplied by the external saphenous nerve. 
The adjoining sides of the great toe or second toe are also supplied by the 
internal branch of the anterior tibial. It frequently happens that some of the 
outer branches of the musculo-cutaneous are absent, their place being then taken 
by branches of the external saphenous nerve. 
Surgical Anatomy.-The lumbar plexus passes through the Psoas muscle, and, therefore, 
in psoas abscess any or all of its branches may be irritated, causing severe pain in the parts to 
which the irritated nerves are distributed. The genito-crural nerve is the one which is most 
frequently implicated. This nerve is also of importance, as it is concerned in one of the 
reflexes employed in the investigation of diseases of the spine. If the skin over the inner 
side of the thigh just below Poupart's ligament, the part supplied by the crural branch of the 
genito-crural nerve, be gently tickled in a male child, the testicle will be noticed to be drawn 1018 
THE NERVOUS SYSTEM 
upward through the action of the 'Cremaster muscle, which is supplied by the genital branch of 
the same nerve. The same result may sometimes be noticed in adults, and can almost always be 
produced by severe stimulation. This reflex, when present, show's that the portion of the cord 
from which the first and second lumbar nerves are derived is in a normal condition. 
1'he anterior crural nerve is in danger of being injured in fractures oj the true pelvis, since 
the fracture most commonly takes place through the ascending ramus of the os pubis, at or 
near the point where this nerve crosses the bone. It is also liable to be injured in fractures 
and dislocations of the femur, and is likely to be pressed upon, and its functions impaired, 
in some tumors growing in the pelvis. Moreover, on account of its superficial position, it is 
exposed to injury in wounds and stabs in the groin. When this nerve is paralyzed, the patient 
is unable to Hex his hip completely, on account of the loss of motion in the Iliacus; or to extend 
the knee on the thigh, on account of paralysis of the Quadriceps extensor cruris; there are com- 
plete paralysis of the Sartorius and partial paralysis of the Pectineus. There is loss of sensation 
down the front and inner side of the thigh, except in that part supplied by the crural branch of 
the genito-crural nerve, and by the ilio-inguinal nerve. There is also loss of sensation down 
the inner side of the leg and foot as far as the ball of the great toe. 
The obturator nerve is of special surgical interest. It is rarely paralyzed alone, but occasionally 
is paralyzed in association with the anterior crural. The principal interest attached to it is in 
connection with its supply to the knee; pain in the knee being symptomatic of many diseases 
in which the trunk of this nerve, or one of its branches, is irritated. Thus it is well known that 
in the earlier stages of hip-joint disease the patient does not complain of pain in that articulation, 
but on the inner side of the knee, or in the knee-joint itself, both these articulations being sup- 
plied by the obturator nerve, the final distribution of the nerve being to the knee-joint. Again, 
the same thing occurs in sacro-iliac disease: pain is complained of in the knee-joint or on its 
inner side. The obturator nerve is in close relationship with the sacro-iliac articulation, passing 
over it, and, according to some anatomists, distributing filaments to it. Again, in cancer of 
the sigmoid flexure, and even in cases where masses of hardened fteces are impacted in this 
portion of the gut, pain is complained of in the knee. The left obturator nerve lies beneath the 
sigmoid flexure, and is readily pressed upon and irritated when disease exists in this part of the 
intestine. Finally, pain in the knee forms an important diagnostic sign in obturator hernia. 
The hernial protrusion as it passes out through the opening in the obturator membrane presses 
upon the nerve and causes pain in the parts supplied by its peripheral filaments. When the 
obturator nerve is paralyzed, the patient is unable to press his knees together or to cross one 
leg over the other, on account of paralysis of the Adductor muscles. Rotation outward of the 
thigh is impaired from paralysis of the Obturator externus. Sometimes there is loss of sensation 
in the upper half of the inner side of the thigh. 
The great sciatic nerve is liable to be pressed upon by various pelvic tumors, giving rise to 
pain along its trunk, to which the term sciatica is applied. Tumors growing from the pelvic 
viscera, or bones, aneurisms of some of the branches of the internal iliac artery, calculus in the 
bladder when of large size, accumulation of faeces in the rectum, may all cause pressure on the 
nerve inside the pelvis, and give rise to sciatica. Outside the pelvis exposure to cold, violent 
movements of the hip-joint, exostoses or other tumors growing from the margin of the sacro- 
sciatic foramen, may also give rise to the same condition. When paralyzed there is loss of 
motion in all the muscles below' the knee, and loss of sensation in the same situation, except the 
upper half of the back of the leg, supplied by the small sciatic and the upper half of the inner 
side of the leg, when the communicating branch of the obturator is large. 
The sciatic nerve has been frequently cut down upon and stretched, or has been acupunctured 
for the relief of sciatica. The nerve has also been stretched in cases of locomotor ataxia, the 
anaesthesia of leprosy, etc. In order to define it on the surface, a point is taken at the junction 
of the middle and low'er third of a line stretching from the posterior superior spine of the ilium 
to the outer part of the tuber ischii, and a line is drawn from this point to the middle of the upper 
part of the popliteal space. The line must be slightly curved with its convexity outward, and as 
it passes downward to the lower border of the Gluteus maximus is slightly nearer the tuberosity 
of the ischium than to the great trochanter, as it crosses a line drawn between these two points. 
The operation of stretching the sciatic nerve is performed by making an incision over the course 
of the nerve about the centre of the thigh. The skin, superficial structures, and deep fascia 
having been divided, the interval between the inner and outer hamstrings is to be defined, and 
these muscles respectively pulled inward and outward with retractors. The nerve will be found a 
little to the inner side of the Biceps. It is to be separated from the surrounding structures, hooked 
up with the finger, and stretched by steady and continuous traction for two or three minutes. 
The sciatic nerve may also be stretched by what is known as the "dry" plan. The patient is 
laid on his back, the foot is extended, the leg flexed on the thigh, and the thigh strongly flexed 
on the abdomen. While the thigh is maintained in this position the leg is forcibly extended to 
its full extent, and the foot as fully flexed on the leg. This last-named method is uncertain. 
The position of the external popliteal nerve, close behind the tendon of the Biceps on the outer 
side of the ham, should be remembered in subcutaneous division of the tendon. After it is divided, THE FIRST OR OLFACTORY NERVE 
1019 
a cord often rises up close beside it, which might be mistaken for a small undivided portion of 
the tendon, and the surgeon might be tempted to reintroduce his knife and divide it. This must 
never be done, as the cord is the external popliteal nerve, which becomes prominent as soon as 
the tendon is divided. 
THE CEREBRAL OR CRANIAL NERVES (NERVI CEREBRALES). 
The cranial nerves arise from some part of the cerebro-spinal centre, and are 
transmitted through foramina in the base of the cranium. They have been named 
numerically, according to the order in which they pass through the dura mater 
lining the base of the skull. Other names are also given to them, derived from 
the parts to which they are distributed or from their functions. Taken in their 
order, from before backward, they are as follows: 
1st. Olfactory. 
2d. Optic. 
3d. Motor oculi. 
4th. Trochlear (Pathetic). 
5th. Trifacial (Trigeminus). 
6th. Abducent. 
7th. Facial (Portio dura). 
8th. Auditory (Portio mollis). 
9th. Glosso-pharyngeal. 
10th. Pneumogastric (or Vagus). 
11th. Spinal accessory. 
12th. Hypoglossal. 
All the cranial nerves are connected to some part of the surface of the brain. 
This is termed their superficial or apparent origin. But their fibres may, in all 
cases, be traced deeply into the substance of the brain and to some special centre of 
gray matter, termed a nucleus. This is called their deep or real origin. The nerves, 
after emerging from the brain at their apparent origin, pass through foramina or 
tubular prolongations in the dura mater, leave the skull through foramina in its 
base, and pass to their final distribution. 
THE FIRST OR OLFACTORY NERVE (N. OLFACTORIUS) (Fig. 660). 
The olfactory nerves are the special nerves of the sense of smell, and are 
about twenty in number on each side. These filaments constitute the first or 
olfactory nerves. They are given off from the under surface of the olfactory bulb, 
an oval mass of a grayish color, which rests on the cribriform plate of the eth- 
moid bone, and forms the anterior expanded extremity or a slender process of 
brain-substance, named the olfactory tract. The olfactory tract and bulb have 
already been described (p. 880). The olfactory tubercle (trigonum oljactorium) 
is a small triangular mass of gray matter between the diverging roots of the optic 
tract (p. 881). 
Each nerve is surrounded by tubular prolongations from the dura mater and 
pia mater, the former being lost on the periosteum lining the nose, the latter in 
the neurilemma of the nerve. The nerves, as they enter the nares, are divisible 
into two groups: an inner group, larger than those on the outer wall, spread out 
over the upper third of the septum; and an outer set, which is distributed over 
the superior turbinated bone, and the surface of the ethmoid in front of it. As 
the filaments descend, they unite in a plexiform network, and are believed by 
most observers to terminate by becoming continuous with the deep extremities 
of the olfactory cells. 
The olfactory nerves differ in structure from other nerves in being composed 
exclusively of non-medullated fibres. They are deficient in the white substance 
of Schwann, and consist of axis-cylinders, with a distinct nucleated sheath, 
in which there are, however, fewer nuclei than in ordinary non-medullated 
fibres. 1020 
THE NERVOUS SYSTEM 
The Olfactory Path (Figs. 660 and 661).-Impressions from the upper portion 
of the Schneiderian mucous membrane pass along the olfactory nerves, reach the 
olfactory bulb, and traverse the olfactory tract to the cerebral hemisphere of 
the same side. The cortical area of the sense of smell is in the uncus hip- 
Fig. 660.-The olfactory bulb and tract. A, Schneiderian membrane in nose in which lies peripheral olfac- 
tory neurone; B, glomerulus of olfactory bulb; C, mitral cells with dendrites in B and axones in D olfactory 
lobe; E, granule cells; F, cells in olfactory lobe; H, G, fibres of olfactory tract. (Ramon y Cajal.) 
pocampi. Impressions which are conveyed by the internal root pass to Broca's 
area which is in front of the inner root of the olfactory tract, to the anterior 
extremity of the gyrus fornicatus, the cingulum, and the uncinate fasciculus to 
the cortical centre (Santee). Impressions travelling by the middle root reach 
Fig. 661.-The olfactory system and tracts. Bol, olfactory bulb; Pol, olfactory tract; Rolp, deep olfactory 
fibres; Roli, internal olfactory fibres; Role, external olfactory fibres. The deep fibres pass to the thalamus (Th) 
and its nuclei; Tc, tuber cinereum; Tm, tuber mamillare; and to tsc, taenia semicircularis, and tth, taenia 
thalami; also into the anterior commissure, coa. The internal olfactory fibres pass into the striae of Lancisi, 
sL, and thus to the fasciola cinerea, Fc. The external olfactory fibres pass directly to the uncinate gyrus, U. Tg, 
fornix from the corpus mamillare (Tin) to Ammon's horn (Cg); NA, nucleus amygdalae; Cing, cingulum; Cc, 
corpus callosum; Fc, fasc. cinerea; FG, Gudden's fasciculus; FM, fasc. retroflexus of Meynert; Na, ant. nuc. of 
thalamus; Gip, interpeduncular ganglion; Gh, ganglion; habenula; Qa, Qp, corp, quadrigemina; Po, pons; VA, 
fascic. Vicq, d'Azyr. (Dejerine.) 
the trigone and then pass to the cortical centre, as do those by way of the inter- 
nal root, or they reach it by way of the anterior commissure (Santee). The outer 
root conducts impulses directly to the cortical area. Fig. 661 shows the olfac- 
tory path according to Dejerine. THE SECOND OR OPTIC NERVE 
1021 
Surgical Anatomy.-Destruction of the olfactory tract of one side causes loss of smell (anos- 
mia) on the side of the injury, because the olfactory tract is uncrossed. In severe injuries to the 
head the olfactory bulb may become separated from the olfactory nerves, thus producing loss 
of the sense of smell, and with this a considerable loss in the sense of taste, as much of the per- 
fection of the sense of taste is due to the sapid substances being also odorous and simultaneously 
exciting the sense of smell. When the sense of smell is lost, an individual cannot distinguish 
the flavor of food, but he can distinguish that a substance is salt, or sweet, or bitter, or acid. 
The most usual cause of injury to the olfactory nerve is fracture of the base of the skull, the 
line of fracture passing through the cribriform plate of the ethmoid bone, but a blow upon the 
face, forehead, or back of the head, which does not produce fracture may injure the nerve. 
THE SECOND OR OPTIC NERVE (N. OPTICUS) (Fig. 662). 
The second or optic nerve, the special nerve of the sense of sight, is distributed 
exclusively to the eyeball. It joins the eyeball about one-eighth of an inch to the 
inner side of the axis of the globe, penetrates the fibrous coat and the vascular 
tunic, and at the optic disk is expanded and forms part of the retina. The nerves 
of opposite sides are connected together at the commissure, and from the back 
of the commissure they may be traced to the 
brain, under the name of the optic tracts. 
The Optic Tract.-The optic tract, at its 
connection with the brain, is divided into two 
bands, external and internal. The external 
band is the larger; it arises from the external 
geniculate body and from the under part of the 
pulvinar of the optic thalamus, and is partly 
continuous with the brachium of the anterior 
or upper quadrigeminal body. The internal 
band curves around the crusta, and passes 
beneath the internal geniculate body, with 
which it is connected, and then appears to lose 
itself in the brachium of the posterior or infe- 
rior quadrigeminal body. The fibres by which 
it is connected to the internal geniculate body 
are merely commissural, forming part of Gud- 
den's commissure. From this origin the tract 
winds obliquely across the under surface of 
the crus cerebri, in the form of a flattened band, and is attached to the crus by 
its anterior margin. It then assumes a cylindrical form, and, as it passes for- 
ward, is connected with the tuber cinereum and lamina cinerea. It finally joins 
with the tract of the opposite side to form the optic commissure. 
The Optic Commissure (chiasma opticum) (Figs. 662 and 663, and p. 882) 
is somewhat quadrilateral in form, rests upon the olivary eminence and on the 
anterior part of the diaphragma sellae, being bounded, 
above, by the lamina cinerea ; behind by the tuber 
cinerereum; on either side by the anterior perforated 
space. Within the commissure, the optic nerves of 
the two sides undergo a partial decussation (Figs. 663 
and 664). The fibres which form the inner margin of 
each tract and posterior part of the commissure have 
no connection with the optic nerves. They simply 
pass across the commissure from one hemisphere 
of the brain to the other, and connect the internal geniculate bodies of the two 
sides. They are known as the inter-cerebral fibres of the optic commissure or the 
commissure of Gudden. The remainder and principal part of the optic com- 
Fig. 662.-The left optic nerve and optic 
tracts. 
To optic ■nerve 
of same side. 
Of opposite 
side. 
Fig. 663.-Course of the fibres 
in the optic commissure. THE NERVOUS SYSTEM 
1022 
missure consists of two sets of fibres, crossed and uncrossed. The crossed fibres, 
which are the more numerous, occupy the central part of the chiasma, and pass 
from the optic tract of one side to the optic nerve of the other, decussating in 
the commissure with similar fibres of the opposite tract. The uncrossed fibres 
occupy the outer part of the chiasma, and pass from the tract of one side to the 
nerve of the same side.1 
The great majority of the fibres of the optic nerve consist of the afferent axones 
of nerve-cells in the retina. Some few, however, are efferent fibres, and grow out 
from the brain. The afferent fibres end in arborizations around the cells in the 
external geniculate body, pulvinar, nucleus of the motor oculi nerve, and the 
upper quadrigeminal body. The external geniculate body and pulvinar are some- 
times termed the lower visual centres. From these nuclei other fibres are pro- 
longed to the cortical half-visual centre, which, according to most observers, is 
situated in the cuneus, and probably also, to a small extent, in the curved portion 
of the occipital lobe (Fig. 664). 
It should be stated that some fibres are detached from the optic tract, and pass 
through the crus cerebri to the nucleus of the third nerve. These fibres are small, 
and may be regarded as afferent branches for the sphincter pupillae and ciliary 
muscles. Other fibres pass to-the cerebellum through its superior peduncles, while 
others, again, are lost in the pons. 
The optic nerves arise from the forepart of the commissure, and, diverging 
from one another, become rounded in form and firm in texture, and are enclosed in 
a sheath derived from the pia mater and arachnoid. As each nerve passes through 
the corresponding optic foramen it receives a sheath from the dura mater; and as 
it enters the orbit this sheath subdivides into two layers, one of which becomes con- 
tinuous with the periosteum of the orbit; the other forms the proper sheath of the 
nerve and surrounds it as far as the sclerotic. The nerve passes forward and out- 
ward through the cavity of the orbit, pierces the sclerotic and choroid coats at the 
back part of the eyeball, about one-eighth of an inch to the nasal side of its centre, 
and expands into the retina. A small artery, the arteria centralis retinae, per- 
forates the optic nerve a little behind the globe, and runs along its interior in a 
tubular canal of fibrous tissue. It supplies the inner surface of the retina, and is 
accompanied by corresponding veins. 
The Optic Path (Fig. 664)4-Impulses of sight originate in the retina. From 
the right half of each retina impulses pass by way of the optic nerves to the right 
optic tract. From the left half of each retina impulses pass by way of the optic 
nerves to the left optic tract. Impulses from the nasal half of each retina pass 
by decussated fibres to the opposite optic tract. Impulses from the temporal 
half of the retina pass by undecussated fibres to the optic tract of the same side, 
although a few fibres may cross farther back through the quadrigeminal bodies. 
From the optic tract impulses pass to the external geniculate body, pulvinar, 
upper quadrigeminal body, and nucleus of the motor oculi nerve. From the 
external geniculate body and pulvinar impulses pass by way of the optic radiatus 
through the posterior segment of the internal capsule to the half-vision centre in 
the cuneus and the convexity of the occipital lobe. The superior quadrigeminal 
body and the nucleus of the third nerve produce ocular reflexes and the pupil- 
lary reflex. 
Surgical Anatomy.-The optic nerve is peculiarly liable to become the seat of neuritis or 
undergo atrophy in affections of the central nervous system, and, as a rule, the pathological 
relationship between the two affections is exceedingly difficult to trace. There are, however, 
certain points in connection with the anatomy of this nerve which tend to throw light upon the 
frequent association of these affections with intracranial disease: (1) From its mode of develop- 
1 A specimen of congenital absence of the optic commissure is to be found in the Museum of the Westminster 
Hospital. See also Henle, Nervenlehre, p. 393, ed 2.-Ed, of 15th English edition. THE SECOND OR OPTIC NERVE 
1023 
ment and from its structure the optic nerve must be regarded as a prolongation of the brain-sub- 
stance, rather than as an ordinary cerebro-spinal nerve. (2) As it passes from the brain it receives 
sheaths from the three cerebral membranes -a perineural sheath from the pia mater, an inter- 
mediate sheath from the arachnoid, and an outer sheath from the dura mater, which is also con- 
nected with the periosteum as it passes through the optic foramen. These sheaths are separated 
from each other by spaces which communicate with the subdural and subarachnoid spaces 
respectively. The innermost or perineural sheath sends a process around the arteria centralis 
retinae into the interior of the nerve, and enters intimately into its structure. Thus inflammatory 
affections of the meninges or of the brain may readily extend themselves along these spaces or 
along the interstitial connective tissue in the nerve. 
The course of the fibres in the optic commissure has an important pathological bearing, and 
has been the subject of much controversy. Microscopic examination, experiments, and pathology 
all seem to point to the fact that there is a partial decussation of the fibres, each tract supplying 
LEFT EYE 
RIGHT 
EYE 
o 
UNCROSSED FIBRES FROM LEFT HALF 
OF LEFT RETINA TO LEFT CENTRES 
MACULA LUTEA 
CHIASMA 
o 
A 
* 
CROSSED FIBRES FROM LEFT HALF 
OF RIGHT RETINA TO LEFT CEN- 
TRES 
GUDDEN'S 
COMMISSURE 
INTERNAL GENICULATE BODY 
AND ITS NERVE CELLS 
EXTERNAL GENICULATE BODY 
AND ITS NERVE CELLS 
ANTERIOR 
Q.UADRI 
GEM I NA 
POSTERIOR QUADRI GEM I NA 
CONNECTING LEFT SIDE OF BRAIN 
WITH LEFT HALF OF RETINA AND 
CONSEQUENTLY RIGHT HALF OF 
FIELD OF VISION 
cORTEX OF CUNEUS 
loPTIC RADIATION 
Fig. 664.-Diagram of the course of the optic fibres. (W. Keiller in Gerrish's Anatomy.) 
the corresponding half of each eye, so that the right tract supplies the right half of each eye, 
and the left tract the left half of each eye. At the same time, Charcot believes-and his view 
has met with general acceptation -that the fibres which do not decussateat the optic commis- 
sure have already decussated in the corpora quadrigemina, so that lesion of the cerebral centre 
of one side causes complete blindness of the opposite eye because both sets of decussating fibres 
are destroyed. AVhereas should one tract-say the right -be destroyed by disease, there will be 
blindness of the right half of both retinae. 
An antero-posterior section through the commissure would divide the decussating fibres, 
and would therefore produce blindness of the inner half of each eye; while a section at the mar- 
gin of the side of the optic commissure would produce blindness of the external half of the retina 
of the same side. 
The optic nerve may also be affected in injuries or diseases involving the orbit, in fractures 
of +he anterior fossa of the base of the skull, in tumors of the orbit itself, or those invading this 
cavity from neighboring parts. THE NERVOUS SYSTEM 
1024 
THE THIRD OR MOTOR OCULI NERVE (N. OCULOMOTORIUS) 
(Figs. 665, 666, 669). 
The third or motor oculi nerve supplies all the muscles of the orbit except the 
Superior oblique and External rectus; it also supplies, through its connection 
with the ciliary ganglion, the Sphincter muscle of the iris and the Ciliary muscle. 
It is rather a large nerve, of rounded form and firm texture. 
Its apparent origin is from the inner surface of the crus cerebri, immediately in 
front of the pons Varolii. The deep origin may be traced through the substantia 
nigra and tegmentum of the crus to a nucleus situated on either side of the median 
line beneath the floor of the aqueduct of Sylvius (Fig. 613). The nucleus of the 
third nerve also receives fibres from the sixth nerve of the opposite side. These 
will be referred to again in the description of the latter nerve. The nucleus of 
the third nerve, considered from a 
physiological standpoint, can be 
subdivided into several smaller 
groups of cells, each group con- 
trolling a particular muscle. The 
nerves to the different muscles 
appear to take their origin from 
before backward, as follows: In- 
ferior oblique, Inferior rectus, 
Superior rectus and Levator pal- 
pebrae, Internal rectus; while from 
the anterior end of the nucleus the 
fibres for accommodation and for 
the Sphincter pupillae take their 
origin. 
On emerging from the brain, the 
nerve is invested with a sheath of 
pia mater, and enclosed in a pro- 
longation from the arachnoid. It 
passes between the superior cere- 
bellar and posterior cerebral arte- 
ries, and then pierces the dura 
mater in front of and external to 
the posterior clinoid process, pass- 
ing between the two processes from 
the free and attached borders of 
the tentorium, which are prolonged 
forward to be connected with the 
anterior and posterior clinoid pro- 
cesses of the sphenoid bone. It 
passes along the outer wall of the 
cavernous sinus (Figs. 454 and 455); above the other orbital nerves, receiving in 
its course one or two filaments from the cavernous plexus of the sympathetic, and 
a communicating branch from the first division of the fifth. It then divides 
into two branches, which enter the orbit through the sphenoidal fissure, between 
the two heads of the External rectus muscle (Fig. 665). On passing through 
the fissure, the nerve is placed below the fourth and the frontal and lachrymal 
branches of the ophthalmic nerve, and has passing between its two divisions the 
nasal nerve (Fig. 675). 
The Superior Division (ramus superior) (Fig. 666).-The superior division, the 
smaller, passes inward over the optic nerve, and supplies the Superior rectus and 
Levator palpebrae. 
Infrat rochlear 
nerve. 
Motor root. 
Sensory root. 
Recurrent filament 
to dura mater. 
Fig. 665.-Nerves of the orbit, seen from above. THE FOURTH OR TROCHLEAR NERVE 
1025 
The Inferior Division {ramus inferior) (Fig. 666).-The inferior division, the larger, 
divides into three branches. One passes beneath the optic nerve to the Internal 
rectus; another, to the Inferior rectus; and the third, the longest of the three, 
passes forward between the Inferior and External recti to the Inferior oblique. 
From this latter a short, thick branch, radix brevis ganglii ciliaris, is given off 
to the lower part of the lenticular ganglion and forms its short or motor root 
LEVATOR PALPEBh£, 
RECTUS SUPERIOR. 
RECTUS INTERNUS. 
OBLIQUUS 
INFERIOR. 
Fig. 666.-Plan of the motor ocnli nerve. (The lenticular ganglion is not shown in normal position. If it were 
the short root would enter the inferior angle.) (After Flower.) 
(Figs. 666, 669, and 670). It also gives off one or two filaments to the Inferior 
rectus. All these branches enter the muscles on their ocular surface, except that 
to the Inferior oblique, which enters its posterior border. 
Surgical Anatomy.-Paralysis of the third nerve maybe the result of many causes: as cere- 
bral disease; conditions causing pressure on the cavernous sinus; periostitis of the bones entering 
into the formation of the sphenoidal fissure; fracture of the orbit. It results, when complete, in 
(1) ptosis, or drooping of the upper eyelid, in consequence of the Levator palpebrae being par- 
alyzed; (2) external strabismus, on account of the unopposed action of the External rectus muscle, 
which is not supplied by the third nerve, and is not therefore paralyzed; (3) dilatation of the pupil, 
because the sphincter fibres of the iris are paralyzed; (4) loss of power of accommodation, as 
the sphincter papillae, the ciliary muscle, and the Internal rectus are paralyzed; (5) slight promi- 
nence of the eyeball, owing to most of its muscles being relaxed. Occasionally paralysis may 
affect only a part of the nerve; that is to say, there may be, for example, a dilated and fixed 
pupil, with ptosis, but no other signs. Irritation of the nerve causes spasm of one or other of 
the muscles supplied by it; thus, there may be internal strabismus from spasm of the Internal 
rectus; accommodation for near objects only from spasm of the Ciliary muscle, or contraction of 
the pupil (myosis), from irritation of the sphincter of the pupil. 
THE FOURTH OR TROCHLEAR NERVE (N. TROCHLEARIS) (Figs. 665 and 669). 
The fourth or trochlear nerve or Patheticus, the smallest of the cranial nerves, 
supplies the Superior oblique muscle. 
The apparent origin, at the base of the brain, is on the outer side of the crus 
cerebri, just in front of the pons Varolii, but the fibres can be traced backward 
behind the corpora quadrigemina to the valve of Vieussens, on the upper surface 
of which the two nerves decussate, decussatio nervorum trochlearium. Its deep 
origin may be traced to a nucleus in the floor of the aqueduct of Sylvius imme- 
diately below that of the third nerve, with which it is continuous (Fig. 613). 
Emerging from the upper end of the valve of Vieussens, the nerve is directed 
outward across the superior peduncle of the cerebellum, and then winds forward 1026 
THE NERVOUS SYSTEM 
around the outer side of the crus cerebri, immediately above the pons Varolii, 
pierces the dura mater in the free border of the tentorium cerebelli, just behind, 
and external to, the posterior clinoid process, and passes forward in the outer 
wall of the cavernous sinus, between the third nerve and the ophthalmic division 
of the fifth (Figs. 454 and 455). It crosses the third nerve and enters the orbit 
through the sphenoidal fissure (Fig. 675). It now becomes the highest of all 
the nerves, lying at the inner extremity of the fissure internal to the frontal 
nerve. In the orbit it passes inward, above the origin of the Levator pal- 
pebrae, and finally enters the orbital surface of the Superior oblique muscle. 
In the outer wall of the cavernous sinus this nerve is not infrequently blended 
with the ophthalmic division of the fifth. 
Branches of Communication.-In the outer wall of the cavernous sinus it 
receives some filaments from the cavernous plexus of the sympathetic. In the 
sphenoidal fissure it occasionally gives off a branch to assist in the formation of 
the lachrymal nerve. 
Branches of Distribution.-It gives off a recurrent branch, which passes 
backward between the layers of the tentorium, dividing into two or three 
filaments which may be traced as far back as the wall of the lateral-sinus. 
Surgical Anatomy.-The fourth nerve when paralyzed causes loss of function in the Superior 
oblique, so that the patient is unable to turn his eye downward and outward. Should the patient 
attempt to do this, the eye on the affected side is twisted inward, producing diplopia or double 
vision. Accordingly, it is said that the first symptom of this disease which presents itself is 
giddiness when going down hill or in descending stairs, owing to the double vision induced by 
the patient looking at his steps while descending. 
THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE (N. TRIGEMINUS) 
(Figs. 665, 667, 668, 669, 670, 671, 672, 673, 674). 
The fifth, trigeminal or trifacial nerve is the largest cranial nerve. It resembles 
a spinal nerve (1) in arising by two roots; (2) in having a ganglion developed on 
its posterior root; and (3) in its function, since it is a compound nerve. It is the 
great sensory nerve of the head and face and the motor nerve of the muscles 
of mastication. Its upper two divisions, portio major, are entirely sensory, the 
third division, portio minor, is partly sensory and partly motor. It arises by two 
roots: of these the anterior is the smaller, and is the motor root (Fig. 613); the 
posterior, the larger and sensory root. Its superficial origin is from the side of 
the pons Varolii, nearer to the upper than the lower border (Fig. 613). The 
smaller root consists of three or four bundles; the larger root consists of numer- 
ous bundles of fibres, varying in number from seventy to a hundred. The two 
roots are separated from one another by a few of the transverse fibres of the 
pons. 'I'he deep origin of the larger or sensory root is chiefly from a long tract 
in the medulla, the lower sensory nucleus, which is continuous below with the 
substantia gelatinosa of Rolando (Fig. 607). The fibres from this nucleus form 
the so-called ascending root of the fifth nerve (Fig. 607); they pass upward through 
the pons and join with fibres from the locus caeruleus or upper sensory nucleus 
(Fig. 613), which is situated to the outer side of the nucleus, from which the lower 
part of the motor root takes origin. The deep origin of the smaller or motor 
root is derived partly from a nucleus embedded in the gray matter of the upper 
part of the floor of the fourth ventricle and partly from a collection of nerve- 
cells situated at the side of the aqueduct of Sylvius, from which the fibres pass 
downward under the name of the descending root of the fifth nerve (Fig. 613). 
The two roots of the nerve pass forward below the tentorium cerebelli as it 
bridges over the notch on the inner part of the superior border of the petrous por- 
tion of the temporal bone (Fig. 668); they then run between the bone and the dura THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1027 
mater to the apex of the petrous portion of the temporal bone, where the fibres of 
the sensory root form the large semilunar or Gasserian ganglion (Figs. 667 and 668), 
while the motor root passes beneath the ganglion without having any connection 
with it, and joins outside the cranium with one of the trunks derived from it 
(Figs. 667 and 668). 
OCULOMOTOR 
NERVE 
TROCHLEAR ABDUCENS 
NERVE NERVE 
MOTOR PORTION 
OF FIFTH NERVE 
SENSORY PORTION 
OF FIFTH NERVE 
OPHTHALMIC 
NERVE 
SEMILUNAR NERVE 
'(Gasserian ganglion) 
SUPERIOR 
MAXI LLARY 
NERVE 
Fig. 667.-The right semilunar or Gasserian ganglion, viewed from the medial side. (Spalteholz.) 
MANDIBULAR 
NERVE 
The Gasserian or Semilunar Ganglion1 (ganglion semilunare) (Figs. 667, 668, 
669, 670, 671, 672, and 673).-The Gasserian or semilunar ganglion is lodged in an 
osteo-fibrous space, the cavum Meckelii 
(Figs. 545 and 668), near the apex 
of the petrous portion of the temporal 
bone. The ganglion is of somewhat 
crescentic form, with its convexity 
turned forward. Its upper surface 
is intimately adherent to the dura 
mater. Besides the small or motor 
root, the large superficial petrosal nerve 
lies underneath the ganglion. 
Branches of Communication.-This 
ganglion receives on its inner side 
filaments from the carotid plexus of 
the sympathetic. 
Branches of Distribution.-It gives 
off minute branches to the ten- 
torium cerebelli and the dura mater 
in the middle fossa of the cranium. 
From its anterior border, which is di- 
rected forward and outward, three 
large branches proceed - the oph- 
thalmic, superior maxillary, and inferior maxillary. The ophthalmic and superior 
maxillary consist exclusively of fibres derived from the larger root and ganglion, 
and are solely nerves of common sensation. The third division, or inferior 
SENSORY ROOT, 
'divided 
SUPERIOR 
PETROSAL SINUS 
MOTOR 
root' 
SEVENTH AND 
"EIGHTH NERVES 
Fig. 668.-The course of the motor root of the fifth nerve. 
(Poirier and Charpy.) 
SENSORY ROOT 
1 A Viennese anatomist, Raimund Balthasar Hirsch (1765), was the first who recognized the ganglionic nature 
of the swelling on the sensory root of the fifth nerve, and called it, in honor of his otherwise unknown teacher, 
Jon. Laur. Gasser, the " Ganglion Gasseri." Julius Casserius, whose name is given to the musculo-cutaneous 
nerve of the arm, was professor at Padua, 1545-1605. (See Hyrtl, Lehrbuch der Anatomie, p. 895 and p. 55.)- 
Ed. of 15th English edition. THE NERVOUS SYSTEM 
1028 
maxillary, is joined outside the cranium by the motor root. This, therefore, 
strictly speaking, is the only portion of the fifth nerve which can be said to 
resemble a spinal nerve. 
Ophthalmic Nerve (n.ophthalmicus) (Figs. 665, 667, 668, 669, 670, 671, 672, and 
673).-The ophthalmic, or first division of the fifth, is a sensory nerve. It supplies 
the eyeball, the lachrymal gland, the mucous lining of the eye and nasal fossae, and 
the integument of the eyebrow, forehead, and nose (Fig. 674). It is the smallest 
of the three divisions of the fifth, arising from the upper part of the Gasserian 
ganglion. It is a short, flattened band, about an inch in length, which passes for- 
ward along the outer wall of the cavernous sinus (Figs. 454 and 455), below the other 
nerves (Fig. 667), and just before entering the orbit, through the sphenoidal fissure, 
divides into three branches-lachrymal, frontal, and nasal (Figs. 665, 669, 670, 671). 
Branches of Communication.-The ophthalmic nerve gives off in the cavernous 
sinus a branch to the dura mater (n. tentorii), is joined by filaments from the 
cavernous plexus of the sympathetic, and gives off minute branches to communi- 
cate with the third and sixth nerves, and not infrequently with the fourth. 
Internal carotid artery 
and carotid plexus. 
Upper division 
of third nerve. 
Sensory roots 
Sd N.^ 
4th Ns 
''Motor root. 
6th N. 
Lower division 
of third nerve. 
Orbital 
nerve. 
Fig. 669.-Nerves of the orbit and ophthalmic ganglion, side view. 
' Branches of Distribution.-It gives off recurrent filaments which pass between 
the layers of the tentorium, and then divide into- 
Lachrymal. Frontal. Nasal 
The Lachrymal Nerve (n. lacrimalis) (Figs. 665, 669, 670, and 671).-The 
lachrymal is the smallest of the three branches of the ophthalmic. It sometimes 
receives a filament from the fourth nerve, but this is possibly derived from the 
branch of communication which passes from the ophthalmic to the fourth. It 
passes forward in a separate tube of dura mater, and enters the orbit through the 
narrowest part of the sphenoidal fissure (Fig. 675). In the orbit it runs along the 
upper border of the External rectus muscle, with the lachrymal artery, and com- 
municates with the temporo-malar branch of the superior maxillary nerve. It 
enters the lachrymal gland and gives off several filaments, which supply the 
gland and the conjunctiva. Finally, it pierces the superior palpebral ligament, 
and terminates in the integument of the upper eyelid, joining with filaments of 
the facial nerve. The lachrymal nerve is occasionally absent, when its place is 
taken by the temporal branch of the superior maxillary. Sometimes the latter 
branch is absent, and a continuation of the lachrymal is substituted for it. THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1029 
Fig. 670.- Plan of the fifth cranial nerve. (The lenticular ganglion is displaced from its normal position. 
The portion where the short root enters is really the inferior angle; in the diagram it is the superior angle.) 
(After Flower.) 1030 
THE NERVOUS SYSTEM 
The Frontal Nerve (n. frontalis) (Figs. 665, 669, and 670).-The frontal is the 
largest division of the ophthalmic, and may be regarded, both from its size and 
direction, as the continuation of the nerve. It enters the orbit above the muscles, 
through the sphenoidal fissure (Fig. 675), and runs forward along the middle line, 
between the Levator palpebrae and the periosteum. Midway between the apex and 
the base of the orbit it divides into two branches, supratrochlear and supra-orbital. 
The Supratrochlear Branch (a. supratrochlear is) (Figs. 665 and 670), the smaller 
of the two, passes inward, above the pulley of the superior oblique muscle, and 
gives off a descending filament, which joins with the infratrochlear branch of the 
nasal nerve. It then escapes from the orbit between the pulley of the Superior 
oblique and the supraorbital foramen, curves up on to the forehead close to the 
bone, ascends beneath the Corrugator supercilii and Occipito-frontalis muscles, 
and, dividing into branches which pierce these muscles, it supplies the integu- 
ment of the lower part of the forehead on either side of the middle line and 
sends filaments to the conjunctiva and skin of the upper lid. 
The Supraorbital Branch (n. supraorbitalis) (Figs. 675 and 670) passes forward 
through the supraorbital foramen, and gives off, in this situation, palpebral fila- 
ments to the upper eyelid. It then ascends upon the forehead, and terminates in 
cutaneous and pericranial branches. 
The cutaneous branches, two in number, an inner and an outer, supply the integ- 
ument of the cranium as far back as the vertex. They are at first situated beneath 
the Occipito-frontalis, the inner branch perforating the frontal portion of the 
muscle, the outer branch its tendinous aponeurosis. 
The pericranial branches are distributed to the pericranium over the frontal and 
parietal bones. 
The Nasal Nerve (n. nasociliaris) (Figs. 665, 669, and 670).-The nasal nerve 
is intermediate in size between the frontal and lachrymal, and more deeply placed 
than the other branches of the ophthalmic. It enters the orbit by way of the 
sphenoidal fissure (Fig. 675) between the two heads of the External rectus, 
and passes obliquely inward across the optic nerve, beneath the Superior rectus 
and Superior oblique muscles, to the inner wall of the orbit, where it passes 
through the anterior ethmoidal foramen, and, entering the cavity of the cranium, 
traverses a shallow groove on the front of the cribriform plate of the ethmoid 
bone, and passes down, through the slit by the side of the crista galli, into the 
nose (Fig. 672), where it divides into two branches, an internal and an external 
branch. The internal branch {rami nasales mediates) supplies the mucous mem- 
brane near the forepart of the septum of the nose. The external branch (rami 
nasales laterales) descends in a groove on the inner surface of the nasal bone, and 
supplies a few filaments to the mucous membrane covering the forepart of the 
outer wall of the nares as far as the inferior spongy bone; it then leaves the cavity 
of the nose, between the lower border of the nasal bone and the upper lateral 
cartilage of the nose, and, passing down beneath the Compressor nasi, supplies 
the integument of the ala and the tip of the nose, joining with the facial nerve. 
Branches.-The branches of the nasal nerve are the ganglionic, ciliary, and infra- 
trochlear. 
The Ganglionic Branch, or the long root of the ciliary ganglion (radix longa ganglii 
ciliaris) (Figs. 666, 669, and 670), is a slender branch, about half an inch in 
length, which usually arises from the nasal nerve, between the two heads of the 
External rectus muscle. It passes forward on the outer side of the optic nerve, 
and enters the postero-superior angle of the ciliary ganglion, forming its long 
root. It is sometimes joined by a filament from the cavernous plexus of the 
sympathetic or from the superior division of the third nerve. 
The Long Ciliary Nerves (nn. ciliares longi) (Fig. 670), two or three in number, 
are given off from the nasal as it crosses the optic nerve. They join the short THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1031 
ciliary nerves (Figs. 666, 669, and 670) from the ciliary ganglion, pierce the pos- 
terior part of the sclerotic, and, running forward between it and the choroid, are 
distributed to the ciliary muscle, iris, and cornea. 
The Infratrochlear Branch (n. infratrochlearis) (Figs. 665 and 670) is given off 
just before the nasal nerve passes through the anterior ethmoidal foramen. It 
runs forward along the upper border of the Internal rectus muscle, and is joined, 
beneath the pulley of the Superior oblique, by a filament from the supratrochlear 
nerve. It then passes to the inner angle of the eye, and supplies the integument 
of the eyelids and side of the nose, the conjunctiva, the lachrymal sac, and the 
caruncula lacrimalis. 
Connected with the three divisions of the fifth nerve are four small ganglia. 
With the first division is connected the ophthalmic ganglion; with the second 
division, the spheno-palatine or Meckel's ganglion; and with the third, the otic and 
submaxillary ganglia. All the four receive sensory filaments from the fifth nerve, 
and motor and sympathetic filaments from various sources; these filaments are 
called the roots of the ganglia. 
The Ophthalmic, Lenticular or Ciliary Ganglion (ganglion ciliare) (Figs. 666, 669, 
and 670) is a small, quadrangular, flattened ganglion, of a reddish-gray color, and 
about the size of a pin's head, situated at the back part of the orbit between the 
optic nerve and the External rectus muscle, lying generally on the outer side of 
the ophthalmic artery. It is enclosed in a quantity of loose fat, which makes its 
exposure by dissection somewhat difficult. 
Its branches of communication or roots are three, all of which enter its posterior 
border. One, the long or sensory root (radix longa ganglii ciliaris), is derived 
from the nasal branch of the ophthalmic and joins the superior angle of the 
ganglion. The second, the short or motor root (radix brevis ganglii ciliaris), is a 
short, thick nerve, occasionally divided into two parts, which is derived from the 
branch of the third nerve to the Inferior oblique muscle, and is connected with 
the inferior angle of the ganglion. The third, the sympathetic root (radix sympa- 
thetica ganglii ciliar is), is a slender filament from the cavernous plexus of the 
sympathetic. This is frequently blended with the long root, though it some- 
times passes to the ganglion separately. According to Tiedemann, this ganglion 
receives a filament of communication from the spheno-palatine ganglion. 
Its branches of distribution are the short ciliary nerves (nn. ciliares breves') (Figs. 
666, 669, and 670). These are delicate filaments, from six to ten in number, which 
arise from the forepart of the ganglion in two bundles, connected with its superior 
and inferior angles; the lower bundle is the larger. They run forward with the 
ciliary arteries in a wavy course, one set above and the other below the optic 
nerve, and are accompanied by the long ciliary nerves from the nasal nerve 
They pierce the sclerotic at the back part of the globe, pass forward in delicate 
grooves on its inner surface, and are distributed to the Ciliary muscle, iris, and 
cornea. Tiedemann has described one small branch as penetrating the optic 
nerve with the arteria centralis retinae. 
The circular fibres of the iris are innervated by the third nerve; the radiating 
fibres are innervated by the sympathetic. 
The Superior Maxillary Nerve (n. maxillaris) (Figs. 667, 668, 669, 670, 671, 
and 672).-The superior maxillary or second division of the fifth is a sensory nerve. 
It is intermediate, both in position and size, between the ophthalmic and inferior 
maxillary. It commences at the middle of the Gasserian ganglion as a flattened 
plexiform band (Fig. 667), and, passing horizontally forward, it leaves the skull 
through the foramen rotundum (Fig. 668), where it becomes more cylindrical in 
form and firmer in texture. It then crosses the spheno-maxillary fossa (Fig. 67), 
enters the orbit through the spheno-maxillary fissure, traverses the infraorbital 
canal in the floor of the orbit, and appears upon the face of the infraorbital fora- 1032 
THE NERVOUS SYSTEM 
men. After it enters the infraorbital canal the nerve is usually called the infra- 
orbital (n. infraorbital is), and the infraorbital nerve is the terminal branch of 
the superior maxillary nerve (Fig. 671). At its termination the nerve lies beneath 
the Levator labii superioris muscle, and divides into a leash of branches, which 
spread out upon the side of the nose, the lower eyelid, and upper lip, joining 
with filaments of the facial nerve. 
Branches of Distribution.-The branches of this nerve may be divided into four 
groups: 1. Those given off in the cranium. 2. Those given off in the spheno- 
maxillary fossa. 3. Those in the infraorbital canal. 4. Those on the face. 
In the cranium 
Meningeal. 
Orbital or temporo-malar. 
Spheno-palatine. 
. Posterior superior dental. 
Spheno-maxillary fossa 
Infraorbital canal 
Middle superior dental. 
Anterior superior dental. 
Palpebral. 
Nasal. 
Labial. 
On the face 
The Meningeal Branch (n. meningeus medius).-The meningeal branch is given 
off by the superior maxillary nerve directly after its origin from the Gasserian 
ganglion; it accompanies the middle meningeal artery and supplies the dura 
mater of the middle fossa of the base of the skull. 
The Orbital or Temporo-malar Branch (n. zygomaticus) (Figs. 669, 670, and 671). 
-The orbital or temporo-malar branch arises in the spheno-maxillary fossa, 
enters the orbit by the spheno-maxillary fissure, and divides at the back of that 
cavity into two branches, temporal and malar. 
The Temporal Branch (ramus zygomaticotemporalis) runs in a groove along the 
outer wall of the orbit (in the malar bone), receives a branch of communication 
from the lachrymal, and, passing through a foramen in the malar bone, enters the 
temporal fossa. It ascends between the bone and the substance of the Temporal 
muscle, pierces this muscle and the temporal fascia about an inch above the 
zygoma, and is distributed to the integument covering the temple and side of 
the forehead, communicating with the facial and the anriculo-temporal branch of 
the inferior maxillary nerve. As it pierces the temporal fascia it gives off a 
slender twig, which runs between the two layers of the fascia to the outer angle 
of the orbit. 
The Malar Branch (ramus zygomaticojacialis) passes along the external inferior 
angle of the orbit, emerges upon the face through a foramen in the malar bone, 
and, perforating the Orbicularis palpebrarum muscle, supplies the skin on the 
prominence of the cheek, where it is named the subcutaneous malae. It joins with 
the facial and the palpebral branches of the superior maxillary. 
The Spheno-palatine Branches (nn. sphenopalatini) (Figs. 670 and 671).-The 
spheno-palatine branches, two in number, descend to the spheno-palatine 
ganglion, of which ganglion they are the sensory or short roots. 
The Posterior Superior Dental Branches (rami alveolares superiores posteriores) 
(Figs. 670 and 671).-The posterior superior dental branches arise from the trunk 
of the nerve just as it is about to enter the infraorbital canal; they are generally 
two in number, but sometimes arise by a single trunk, and immediately divide 
and pass downward on the tuberosity of the superior maxillary bone. They give 
off several twigs to the gums and neighboring parts of the mucous membrane of 
the cheek, superior gingival branches (rami gingivales superiores). They then 
enter the posterior dental canals on the zygomatic surface of the superior maxil- 
lary bone, and, passing from behind forward in the substance of the bone, THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1033 
communicate with the middle dental nerve by a plexus formation, and give off 
branches to the lining membrane of the antrum and three twigs to each of the 
molar teeth. These twigs enter the foramina at the apices of the fangs and 
supply the pulp. 
The Middle Superior Dental Branch (ramus alveolaris superior medius) (Fig. 
670).-The middle superior dental branch is given off from the superior maxil- 
lary nerve in the back part of the infraorbital canal, and runs downward and 
forward in a special canal in the outer wall of the antrum to supply the two 
bicuspid teeth. It communicates with the posterior and anterior dental branches 
by a plexus formation. At its point of communication with the posterior 
branch, above the root of the second bicuspid tooth, is a slight thickening which 
has received the name of the ganglion of Valentin; and at its point of commu- 
nication with the anterior branch is a second enlargement, which is called the 
ganglion of Bochdalek. Neither of these is probably a true ganglion. 
Sensory root. 
Ufotor root. 
Auriculo-temporal 
nerve. 
Fig. 671.-Distribution of the second and third divisions of the fifth nerve and submaxillary ganglion. 
The Anterior Superior Dental Branch (ramus alveolaris superior anteriores) (Fig. 
670).-The anterior superior dental branch, of large size, is given off from the 
superior maxillary nerve just before its exit from the infraorbital foramen; it 
enters a special canal in the anterior wall of the antrum, and divides into a series 
of branches which supply the incisor and canine teeth. It communicates with 
the middle dental nerve by a plexus, and gives off a nasal branch, which passes 
through a minute canal into the nasal fossa, and supplies the mucous membrane 
of the forepart of the inferior meatus and the floor of the cavity, communi- 
cating with the nasal branches from Meckel's ganglion. 
The superior dental plexus (plexus dentalis superior) is formed by twigs of the 
three superior dental nerves. From the plexus come the nerves which supply the THE NERVOUS SYSTEM 
1034 
teeth of the upper jaw (rami dentales superiores) and the gums (rami gingivales 
superiores). 
The branches upon the face are known as the rami n. infraorbital is (Fig. 671). 
'rhere are three sets of them. 
The Palpebral Branches (rami palpebrales inferiores).--The palpebral branches 
pass upward beneath the Orbicularis palpebrarum muscle. They supply the 
integument and conjunctiva of the lower eyelid, with sensation, joining at 
the outer angle of the orbit with the facial nerve and the malar branch of the 
orbital. 
The Nasal Branches (rami nasales interni).-The nasal branches pass inward; 
they supply the integument of the side of the nose and join with the nasal branch 
of the ophthalmic. 
The Labial Branches (rami labiales superiores).-The labial branches, the 
largest and most numerous, descend beneath the Levator labii superioris muscle, 
and are distributed to the integument of the upper lip, the mucous membrane 
of the mouth, and the labial glands. 
All these branches are joined, immediately beneath the orbit, by filaments from 
the facial nerve, forming an intricate plexus, the infraorbital plexus. 
The Spheno-palatine or Meckel's Ganglion (ganglion sphenopalatinum) (Figs. 
670 and 672).-The spheno-palatine ganglion, the largest of the cranial ganglia, 
is deeply placed in the spheno-maxillary fossa, close to the spheno-palatine fora- 
men. It is triangular or heart-shaped, of a reddish-gray color, and is situated just 
below the superior maxillary nerve as it crosses the fossa. 
Branches of Communication.-Like the other ganglia of the fifth nerve, it pos- 
sesses a motor, a sensory, and a sympathetic root. Its sensory root is derived 
from the superior maxillary nerve through its two spheno-palatine branches 
(p. 1032). These branches of the nerve are given off in the spheno-maxillary fossa 
and descend to the ganglion. Their fibres, for the most part, pass in front of the 
ganglion, as they proceed to their destination, in the palate and nasal fossa, and 
are not incorporated in the ganglionic mass; some few of the fibres, however, enter 
the ganglion, constituting its sensory root. Its motor root is derived from the facial 
nerve through the large superficial petrosal nerve, and its sympathetic root from 
the carotid plexus, through the large deep petrosal nerve. These two nerves join 
together before their entrance into the ganglion to form a single nerve, the Vidian. 
The Large or Great Superficial Petrosal Branch (n. petrosus superficialis major) 
(Fig. 676) is given off from the geniculate ganglion of the facial nerve in the 
aquaeductus Fallopii; it passes through the hiatus Fallopii; enters the cranial 
cavity, and runs forward, being contained in a groove on the anterior surface 
of the petrous portion of the temporal bone and lying beneath the dura mater. 
It then enters the cartilaginous substance which fills in the foramen lacerum 
medium basis cranii, and, joining with the large deep petrosal branch, forms the 
Vidian nerve. 
The Large or Great Deep Petrosal Branch (n. petrosus profundus) (Fig. 677) is 
given off from the carotid plexus of the sympathetic upon the internal carotid 
artery, and runs through the carotid canal on the outer side of the internal carotid 
artery. It then enters the cartilaginous substance which fills in the foramen 
lacerum medium basis cranii, and joins with the large superficial petrosal nerve 
to form the Vidian. 
'Fhe Vidian Nerve (n. canalis pterygoidei) (Figs. 670 and 672), formed in the 
cartilaginous substance which fills in the middle lacerated foramen by the junc- 
tion of the two preceding nerves, passes forward, through the Vidian canal, with 
the artery of the same name, and is joined by a small ascending nervous branch, 
the sphenoidal branch, from the otic ganglion. Finally, it enters the spheno-maxil- 
lary fossa, and joins the posterior angle of Meckel's ganglion. THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1035 
Branches of Distribution of the Spheno-palatine Ganglion.-Its branches of distri- 
bution are divisible into four groups: ascending, which pass to the orbit; descend- 
ing, to the palate; internal, to the nose; and posterior branches, to the pharynx and 
nasal fossae. 
The Ascending Branches (rami orbitales) are two or three delicate filaments, which 
enter the orbit by the spheno-maxillary fissure, and supply the periosteum. Accord- 
ing to Luschka, some filaments pass through foramina in the suture between the 
os planum of the ethmoid and frontal bones to supply the mucous membrane of 
the posterior ethmoidal and sphenoidal sinuses. 
'rhe Descending or Palatine Branches (nn. palatini) (Figs. 670 and 672) are dis- 
tributed to the roof of the mouth, the soft palate, tonsil, and lining membrane of 
the nose. They are almost a direct continuation of the spheno-palatine branches 
of the superior maxillary nerve, and are three in number-anterior, middle, and 
posterior. 
Termination of 
nano-palatine 
nerve. 
Fig. 672.-The spheno-palatine or Meckel's ganglion and its branches. 
The anterior or large palatine nerve (n. palatinus anterior) descends through 
the large posterior palatine canal, emerges upon the hard palate at the posterior 
palatine foramen, and passes forward through a groove in the hard palate nearly 
as far as the incisor teeth. It supplies the gums, the mucous membrane and glands 
of the hard palate, and communicates in front with the termination of the naso- 
palatine nerve (p. 1036). While in the posterior palatine canal it gives off inferior 
nasal branches (rami nasales posteriores injeriores), which enter the nose through 
openings in the palate bone, and ramify over the inferior turbinated bone, the 
middle and the inferior meatus; and at its exit from the canal a palatine branch 
is distributed to both surfaces of the soft palate. 
The middle or external palatine nerve (n. palatinus medius) descends through 
one of the accessory palatine canals, distributing branches to the uvula, tonsil, 
and soft palate. It is occasionally wanting. 
The posterior or small palatine nerve (n. palatinus posterior) descends with a 
minute artery through the small posterior palatine canal, emerging by a separate 1036 
THE EEE VO US SYSTEM 
opening behind the posterior palatine foramen. It supplies the Levator palati 
and Azygos uvulae muscles,1 the soft palate, tonsil, and uvula. The middle and 
posterior palatine join with the tonsillar branches of the glosso-pharyngeal to form 
the plexus around the tonsil, the circulus tonsillaris. 
The Internal Branches are distributed to the septum and outer wall of the nasal 
fossae. They are the posterior superior nasal and the naso-palatine. 
The posterior superior nasal branches (rami nasales post er lores super lores), three 
in number, enter the back part of the nasal fossa by the spheno-palatine foramen. 
They supply the mucous membrane covering the superior and middle spongy bones, 
and that lining the posterior ethmoidal cells, a few being prolonged to the upper 
and back part of the septum. 
The naso-palatine nerve (n. nasopalatlnus) has been called the nerve of Scarpa 
and also the nerve of Cotunnius. It enters the nasal fossa through the spheno- 
palatine foramen, and passes inward across the roof of the nose, below the orifice 
of the sphenoidal sinus, to reach the septum; it then runs obliquely downward and 
forward along the lower part of the septum, to the anterior palatine foramen, 
lying between the periosteum and mucous membrane. It descends to the roof of 
the mouth through the anterior palatine canal (Fig. 672). The two nerves are here 
contained in separate and distinct canals, situated in the intermaxillary suture, and 
termed the foramina of Scarpa, the left nerve being usually anterior to the right 
one. In the mouth they become united, supply the mucous membrane behind 
the incisor teeth, and join with the anterior palatine nerve. The naso-palatine 
nerve furnishes a few small filaments to the mucous membrane of the septum. 
The Posterior Branches are the pharyngeal or pterygo-palatine and the upper 
posterior nasal branches. 
The pharyngeal or pterygo-palatine nerve (Figs. 670 and 672) is a small branch 
arising from the back part of the spheno-palatine ganglion, being generally blended 
with the Vidian nerve. It passes through the pterygo-palatine canal with the 
pterygo-palatine artery, and is distributed to the mucous membrane of the upper 
part of the pharynx, behind the Eustachian tube. 
The upper posterior nasal branches are a few twigs given off from the posterior 
part of the spheno-palatine ganglion, which run backward in the sheath of the 
Vidian nerve to the mucous membrane at the back part of the roof, septum, and 
superior meatus of the nose and that covering the end of the Eustachian tube. 
The Mandibular or Inferior Maxillary Nerve (n. mandibularis) (Figs. 667, 
669, 670, and 671).-The inferior maxillary or third division of the fifth nerve dis- 
tributes branches to the teeth and gums of the lower jaw, the integument of the 
temple and external ear, the lower part of the face and lower lip, and the muscles 
of mastication; it also supplies the tongue with a large branch. It is the largest of 
the three divisions of the fifth, and is made up of two roots: a large or sensory root, 
proceeding from the inferior angle of the Gasserian ganglion; and a small or motor 
root, which passes beneath the ganglion and unites with the sensory root just after 
its exit from the skull through the foramen ovale (Figs. 667, 668, 670, and 671). 
Immediately beneath the base of the skull this nerve divides into two trunks, 
anterior and posterior. Previous to its division the primary trunk gives off from 
its inner side a recurrent branch and the nerve to the Internal pterygoid muscle. 
The Recurrent or Meningeal Branch (n. spinosus).-The recurrent or meningeal 
branch is given off directly after the exit of the mandibular nerve from the foramen 
ovale. It passes backward into the skull through the foramen spinosum with the 
middle meningeal artery. It divides into two branches, anterior and posterior, which 
accompany the main divisions of the artery and supply the dura mater. The pos- 
1 It is probable that this is not the true motor supply to these muscles, but that they are supplied by the 
ipinal accessory through the pharyngeal plexus. -Ed. of 15th English edition. THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1037 
terior branch also supplies the mucous lining of the mastoid cells. The anterior 
branch communicates with the meningeal branch of the superior maxillary nerve. 
The Internal Pterygoid Nerve (n. pterygoideus internus) (Fig. 670).-The internal 
pterygoid nerve, given off from the inferior maxillary previous to its division, is 
intimately connected at its origin with the otic ganglion. It is a long and slender 
branch, which passes inward to enter the deep surface of the Internal pterygoid 
muscle. 
The anterior and smaller division of the inferior maxillary nerve, which receives 
nearly the whole of the motor root of the fifth nerve, divides into branches which 
supply the muscles of mastication. They are the masseteric, deep temporal, buccal, 
and external pterygoid branches (Figs. 670 and 671). 
The Masseteric Branch (n. massetericus) passes outward, above the External 
pterygoid muscle, in front of the temporo-mandibular articulation and behind the 
tendon of the temporal muscle; it crosses the sigmoid notch with the masseteric 
artery, to the deep surface of the Masseter muscle, in which it ramifies nearly as 
far as its anterior border. It occasionally gives a branch to the Temporal muscle, 
and a filament to the articulation of the jaw. 
The Deep Temporal Branches (nn. temporales profundi), two in number, anterior 
and posterior, supply the deep surface of the Temporal muscle. The posterior 
branch (n. temporalis profundus posterior), of small size, is placed at the back of 
the temporal fossa. It is sometimes joined with the masseteric branch. The 
anterior branch (n. temporalis profundus anterior) is frequently given off from the 
buccal nerve; it is reflected upward, at the pterygoid ridge of the sphenoid, to the 
front of the temporal fossa. Sometimes there are three deep temporal branches, 
and if this maintains the third branch, the middle deep temporal, passes outward 
above the External pterygoid muscle, and runs upward on the bone to enter the 
deep surface of the Temporal muscle. 
The Buccal or Buccinator Branch (n. buccinatorius) passes forward between the 
two heads of the External pterygoid, and downward beneath the inner surface of 
the coronoid processes of the lower jaw, or through the fibres of the Temporal 
muscle, to reach the surface of the Buccinator muscle, upon which it divides into 
a superior and an inferior branch. It gives a branch to the External pterygoid 
during its passage through that muscle, and a few ascending filaments to the 
Temporal muscle, one of which occasionally joins with the anterior branch of the 
deep temporal nerve. The superior or upper branch supplies the integument and 
upper part of the Buccinator muscle, joining with the facial nerve around the 
facial vein. The inferior or lower branch passes forward to the angle of the mouth; 
it supplies the integument and Buccinator muscle, as well as the mucous membrane 
lining the inner surface of that muscle, and joins the facial nerve.1 
'rhe External Pterygoid Nerve (n. pterygoideus externus) is most frequently 
derived from the buccal, but it may be given off separately from the anterior 
trunk of the mandibular nerve. It enters the muscle on its inner surface. 
The posterior and larger division of the inferior maxillary nerve is for the most part 
sensory, but receives a few filaments from the motor root. It divides into three 
branches: auriculo-temporal, lingual (gustatory), and inferior dental (Figs. 670, 671). 
'rhe Auriculo-temporal Nerve (n. auriculotemporalis) (Fig. 673) generally arises 
by two roots, between which the middle meningeal artery passes. It runs back- 
ward beneath the External pterygoid muscle to the inner side of the neck of the 
lower jaw. It then turns upward with the temporal artery, between the external 
ear and the condyle of the jaw, under cover of the parotid gland, and, escaping 
from beneath this structure, ascends over the zygoma and divides into two tem- 
poral branches. 
1 There seems to be no reason to doubt that the branch supplying the Buccinator muscle is entirely a nerve of 
ordinary sensation, and that the true motor supply of this muscle is from the facial.-Ed. of 15th English edition. THE NERVOUS SYSTEM 
1038 
The branches of communication are with the facial and with the otic ganglion. 
The branches of communication with the facial (rami anastomotid cum n. faciali), 
usually two in number, pass forward from behind the neck of the condyle of the 
jaw, to join this nerve at the posterior border of the Masseter muscle. They 
form one of the principal branches of communication between the facial and the 
fifth nerve. The filaments of communication with the otic ganglion are derived 
from the commencement of the auriculo-temporal nerve. 
The branches of distribution are- 
Anterior auricular. 
Branches to the meatus auditorius. 
Articular. 
Parotid. 
Superficial temporal. 
The anterior auricular branches (nn. auriculares anteriores) are usually two in 
number. They supply the front of the upper part of the pinna, being distributed 
principally to the skin covering the front of the helix and tragus. 
Branch to the external auditory meatus (n. meatus auditorii externi) divides into 
two. The two nerves enter the canal between the bony and cartilaginous portion 
of the meatus. They supply the skin lining the meatus; the upper one sending 
a filament to the membrana tympani (ramus membranae tympani). 
A branch to the temporo-mandibular articulation, the articular branch, is usually 
derived from the auriculo-temporal nerve. 
The parotid branches (rami parotidei) supply the parotid gland. 
The superficial temporal branches (rami temporales super/idales') accompany the 
temporal artery to the vertex of the skull, and supplies the integument of the tem- 
poral region, communicating with the facial nerve, and with the temporal branch 
of the temporo-malar, from the superior maxillary. 
The Lingual Nerve or Gustatory Nerve (n. lingual is) (Figs. 670 and 671).-The 
lingual or gustatory nerve supplies the papillae and mucous membrane of the 
anterior two-thirds of the tongue. It is deeply placed throughout the whole of its 
course. It lies at first beneath the External pterygoid muscle, together with the 
inferior dental nerve, being placed to the inner side of this nerve, and is occasion- 
ally joined to it by a branch which may cross the internal maxillary artery. The 
chorda tympani nerve also joins it at an acute angle in this situation. The nerve 
then passes between the Internal pterygoid muscle and the inner side of the 
ramus of the jaw, and crosses obliquely to the side of the tongue over the Superior 
constrictor of the pharynx and the Stylo-glossus muscles, and then between the 
Hyo-glossus muscle and the deep part of the submaxillary gland; the nerve finally 
runs across Wharton's duct, and along the side of the tongue to its apex, lying 
immediately beneath the mucous membrane. 
The branches of communication are with the facial through the chorda tympani, 
with the inferior dental and hypoglossal nerves, and the submaxillary ganglion. The 
chorda tympani branch of the facial joins the lingual nerve under the external 
pterygoid muscle and is distributed with the lingual to the tongue. The hypo- 
glossal nerve and the lingual nerve lie near together, over the Hyo-glossus muscle, 
and the two nerves are joined by loops (rami anastomotid cum n. hypoglosso). 
The branches to the submaxillary ganglion are two or three in number; those 
connected with the hypoglossal nerve form a plexus at the anterior margin of the 
Hyo-glossus muscle. 
The branches of distribution supply the mucous membrane of the mouth, the 
gums, the sublingual gland, the filiform and fungiform papillae and mucous mem- 
brane of the tongue; the terminal filaments communicate, at the tip of the tongue, 
with the hypoglossal nerve. The lingual fibres are fibres of common sensation. 
The chorda tympani fibres which join the lingual nerve are probably taste- 
fibres. THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1039 
The Inferior Dental Nerve (n. alveolaris inferior) (Figs. 670 and 671).-'The 
inferior dental is the largest of the branches of the inferior maxillary nerve. It 
passes downward with the inferior dental artery, at first beneath the External 
pterygoid muscle, and then between the internal lateral ligament and the ramus 
of the jaw to the dental foramen. It then passes forward in the dental canal of the 
inferior maxillary bone, lying beneath the teeth, as far as the mental foramen, 
where it divides into two terminal branches, incisor and mental. 
The Branches of the inferior dental are: the mylo-hyoid, dental, incisor, and 
mental. 
The Mylo-hyoid (n. mylohyoideus) is derived from the inferior dental just as that 
nerve is about to enter the dental foramen. It descends in a groove on the inner 
surface of the ramus of the jaw, in which it is retained by a process of fibrous mem- 
brane. It reaches the under surface of the Mylo-hyoid muscle, and supplies it and 
the anterior belly of the Digastric. 
'The Dental Branches supply the molar and bicuspid teeth. They correspond 
in number to the fangs of those teeth: each nerve entering the orifice at the point 
of the fang and supplying the pulp of the tooth. 
The Incisor Branch is continued onward within the bone to the middle line, and 
supplies the canine and incisor teeth. 
The dental branches and the incisor branch form a plexus (plexus dentalis infe- 
rior), and from this plexus come the branches to the teeth (rami dentales inferiores) 
and to the gums (rami gingivales inferiores). 
The Mental Branch (n. mentalis) emerges from the bone at the mental foramen, 
and divides beneath the Depressor anguli oris muscle into two or three branches; 
one descends to supply the skin of the chin, and another (sometimes two) ascends 
to supply the skin and mucous membrane of the lower lip. These branches com- 
municate freely with the facial nerve. 
Two small ganglia are connected with the inferior maxillary nerve-the otic 
with the trunk of the nerve, and the submaxillary with its lingual branch. 
Otic or Arnold's Ganglion (ganglion oticum) (Figs. 670 and 673).-The otic or 
Arnold's ganglion is a small, oval-shaped, flattened ganglion of a reddish-gray 
color, situated immediately below the foramen ovale, on the inner surface of the 
inferior maxillary nerve, and round the origin of the internal pterygoid nerve. It 
is in relation, externally, with the trunk of the inferior maxillary nerve, at the 
point where the motor root joins the sensory portion; internally, with the car- 
tilaginous part of the Eustachian tube, and the origin of the Tensor palati muscle; 
behind, it lies in the middle meningeal artery. 
Branches of Communication.-This ganglion is connected with the internal 
pterygoid branch of the inferior maxillary nerve by two or three short delicate 
filaments. From this nerve the ganglion may obtain a motor root, and possibly 
also a sensory root, as these filaments from the nerve to the Internal pterygoid 
perhaps contain sensory fibres. The otic ganglion communicates with the glosso- 
pharyngeal and facial nerves through the small superficial petrosal nerve (Figs. 673 
and 676) continued from the tympanic plexus, and through this communication 
it probably receives its sensory root from the glosso-pharyngeal and its motor root 
from the facial; its communication with the sympathetic is effected by a filament 
from the plexus surrounding the middle meningeal artery. The ganglion also 
communicates with the auriculo-temporal nerve (ramus anastomoticus cum n. 
auriculotemporali). This communicating filament is probably a branch from the 
glosso-pharyngeal which passes to the ganglion, and through it and the auriculo- 
temporal nerve to the parotid gland. A slender filament, the sphenoidal, ascends 
from it to the Vidian nerve. 
Branches of Distribution.-Its branches of distribution are a filament to the 
Tensor tympani (n. tensoris tympani) and one to the Tensor palati (n. tensor is veli 1040 
THE NERVOUS SYSTEM 
palatini). The former passes backward on the outer side of the Eustachian tube; 
the latter arises from the ganglion, near the origin of the internal pterygoid nerve, 
and passes forward. The fibres of these nerves are, however, mainly derived 
from the nerve to the Internal pterygoid muscle. It also gives off a small com- 
municating branch to the chorda tympani (ramus anastomoticus cum n. chorda 
tympani). 
The Submaxillary Ganglion {ganglion submaxillare) (Figs. 670 and 671).-The 
submaxillary ganglion is of small size, fusiform in shape, and situated above the 
deep portion of the submaxillary gland, near the posterior border of the Mylo-hyoid 
muscle, being connected by filaments with the lower border of the lingual or 
gustatory nerve. 
Branches of Communication.-This ganglion is connected with the lingual nerve 
by a few filaments (rami co mmuni cantes cum n. lingual i), which join it separately 
at its fore and back part. It also receives a branch from the chorda tympani, by 
which it communicates with the facial, and communicates with the sympathetic 
by filaments from the sympathetic plexus around the facial artery. 
Fig. 673.-The otic ganglion and its branches. 
Branches of Distribution.-These are five or six in number; they arise from the 
lower part of the ganglion, and supply the mucous membrane of the mouth and 
Wharton's duct, some being lost in the submaxillary gland (rami submaxillares). 
The branch of communication from the lingual nerve to the forepart of the gan- 
glion is by some regarded as a branch of distribution, by which filaments of the 
chorda tympani pass from the ganglion to the lingual nerve, and by it are con- 
veyed to the sublingual gland and the tongue. 
Summary of the Distribution and Connections of the Fifth Nerve.-It is the chief 
sensory nerve of the face, the anterior half of the scalp, the mouth, nasal cavity, 
lips, teeth, anterior two-thirds of the tongue, orbit, and eyeball. The clearly 
defined cutaneous distributions of the branches are shown in Fig. 674. The 
motor portion of the nerve supplies the muscles of mast'cation, the mylo-hyoid, 
and the anterior belly of the digastric. By way of branches from the otic 
ganglion it supplies the Tensor tympani and Tensor palati muscles, and by 
way of branches from the spheno-palatine ganglion perhaps supplies the Levator 
palati and Azygos uvulae muscles, although it is more probable that these muscles THE FIFTH, TRIGEMINAL OR TRIFACIAL NERVE 
1041 
receive their motor influence by the spinal accessory through the pharyngeal 
plexus. The ganglia associated with the nerve create communications with the 
sympathetic, the motor oculi, the facial, and the glosso-pharyngeal, and through 
these ganglia, as Prof. Cunningham says, " important organs, areas, arid muscles " 
are innervated. The trigeminal communicates many times with the facial, and 
thus gives sensory fibres to the " muscles of expression supplied by the facial 
nerve."1 
LACHRYMAL N. 
SUPRATROCHLEAR N.- 
SUPRAORBITAL N. 
TEMPORAL BR. 
OF TEMPORO-MALAR 
INFRATROCHLEAR N.- 
NASAL NERVE 
INFRAORBITAL- 
NERVE 
MALAR BR. OF 
TEMPORO-MALAR 
BUCCAL NERVE 
AURICULO-TEMPORAL 
NERVE 
MENTAL NERVE 
Fig. 674.-Sensory areas of the head, showing the general distribution of the three divisions of the fifth 
nerve. Gerrish's Anatomy. (Modified from Testut.) 
Surface Marking.-It will be seen from the above description that the three terminal branches 
of the three divisions of the fifth nerve emerge from foramina in the bones of the skull and pass 
on to the face: the terminal branch of the first division emerging through the supraorbital 
foramen; that of the second through the infraorbital foramen; and the third through the mental 
foramen. The supraorbital foramen is situated at the junction of the internal and middle 
third of the supraorbital arch. If a straight line is drawn from this point to the lower border 
of the inferior maxillary bone, so that it passes between the two bicuspid teeth of the lower jaw, 
it will pass over the infraorbital and mental foramina, the former being situated about one 
centimetre (two-fifths of an inch) below the margin of the orbit, and the latter varying in posi- 
tion according to the age of the individual. In the adult it is midway between the upper and 
lower borders of the inferior maxillary bone; in the child it is nearer the lower border; and in the 
edentulous jaw of old age it is close to the upper margin. 
Surgical Anatomy.-In fracture of the base of the skull, the fifth nerve or one of its branches 
may be injured. It seems certain that occasionally, though seldom, the fifth nerve may be 
actually divided by such an injury. The fifth nerve may be affected in its entirety, or its sensory 
or motor root may be affected, or one of its primary main divisions. In injury to the sensory root 
there is anaesthesia of the half of the face on the side of the lesion, with the exception of the skin 
over the parotid gland; insensibility of the conjunctiva, followed, if the eye is not temporarily 
protected with a watch-glass, by destructive inflammation of the cornea, partly, it is held, from 
loss of trophic influence, and partly, it is certain, from the irritation produced by the presence 
of foreign bodies on it, which are not perceived by the patient, and therefore not expelled by 
the act of winking; dryness of the nose, loss to a considerable extent of the sense of taste, and 
diminished secretion of the lachrymal and salivary glands. In injury to the motor root there is 
impaired action of the lower jaw from paralysis of the muscles of mastication on the affected side. 
The fifth nerve is often the seat of neuralgia, and each of the three divisions has been divided 
or a portion of the nerve excised for this affection. The supraorbital nerve may be exposed 
1 Cunningham's Text-book of Anatomy. 1042 
THE NERVOUS SYSTEM 
by making an incision an inch and a half in length along the supraorbital margin below the 
eyebrow, which is to be drawn upward, the centre of the incision corresponding to the supra- 
orbital notch. The skin and Orbicularis palpebrarum having been divided, the nerve can be 
easily found emerging from the notch and lying in some loose cellular tissue. It should be drawn 
up by a blunt hook and divided, or, what is better, a portion of it should be removed. The 
infraorbital nerve has been divided at its exit by an incision on the cheek; or the floor of the 
orbit has been exposed, the infraorbital canal opened up, and the anterior part of the nerve 
resected; or the whole nerve, together with Meckel's ganglion as far back as the foramen rotun- 
dum, has been removed. This latter operation, though undoubtedly a severe proceeding, appears 
to have been followed by better results than has nerve resection. The operation is performed 
as follows: The superior maxillary bone is first exposed by a T-shaped incision, one limb of 
the incision passing along the lower margin of the orbit, the other from the centre of the first 
cut vertically down the cheek toward the angle of the mouth. The nerve is then found, is divided, 
and a piece of silk is tied to it as a guide. A small trephine (one-half inch) is then applied 
to the bone below, but including the infraorbital foramen, and the antrum opened. The 
trephine is now applied to the posterior wall of the antrum, and the spheno-maxillary fossa 
exposed. The infraorbital canal is now opened up from below by fine cutting-pliers or a 
chisel, and the nerve drawn down into the trephine hole, it being held on the stretch by 
means of the piece of silk; it is severed with fine curved scissors as near the foramen rotundum 
as possible, any branches coming off from the ganglion being also divided.1 The mental 
branch of the inferior dental nerve may be divided at its exit from the foramen through an 
incision made through the mucous membrane where it is reflected from the alveolar process on 
to the lower lip; or a portion of the trunk of the inferior dental nerve may be resected through 
an incision on the cheek through the Masseter muscle, exposing the outer surface of the ramus of 
the jaw. A trephine is then applied over the position of the inferior dental foramen and the 
outer table removed, so as to expose the inferior dental canal. The nerve is dissected out of 
the portion of the canal exposed, and, having been divided after its exit from the mental foramen, 
it is by traction on the end exposed in the trephine-hole, drawn out entire, and cut off as high up 
as possible.2 The inferior dental nerve has also been divided through an incision within the mouth, 
the bony point guarding the inferior dental foramen forming the guide to the nerve. The buccal 
nerve may be divided by an incision through the mucous membrane of the mouth and the Buc- 
cinator muscle just in front of the anterior border of the ramus of the lower jaw (Stimson). 
In inveterate neuralgia of one or two of the branches of the fifth nerve a peripheral opera- 
tion may cure the case, but seldom does. It often gives relief, perhaps for months. In neuralgia 
of the second division or third division, or of the second division and third division, Abbe, of 
New York, opens the skull and divides the nerve or nerves by an intracranial operation, 
removes a piece of nerve so as the foramen of exit is empty, and covers the foramen with rubber 
tissue, to hinder regrowth of the nerve. Other operators, after removing a piece from each 
nerve, have plugged the foramina of the exit with dentists' cement or silver-foil. 
Rose's method of neurectomy is very valuable for neuralgia of the second division. It is a 
modification of the Braun-Lossen method. The infraorbital nerve is exposed, a ligature is 
tied about it, the roof of the infraorbital canal is chiselled open, and the nerve is freed as far 
back as possible. An incision is made from below the external angular process outward along 
the zygoma to in front of the lobule of the ear, downward to just above the angle of the jaw, 
and forward for two inches. The flap is raised and the zygoma is exposed. The root of the 
zygoma is drilled at two points, and the zygomatic process of the temporal bone is drilled at two 
points. The bone is sawed in two places between the drill-holes. The freed arch is lifted down 
and back, the tendon of the temporal muscle is drawn backward, and the pterygo-maxillary 
fossa is thus exposed. The internal maxillary artery is divided between two ligatures. The 
External pterygoid muscle is separated from the greater wing of the sphenoid and from the root 
of the external pterygoid process. The superior maxillary nerve is grasped and twisted off as 
near the ganglion as possible. The entire nerve is then drawn back from the infraorbital foramen 
and removed. The wound is then closed. If the third division is also haunted by neuralgia, 
it too should be removed a few weeks after the performance of Rose's operation. 
If a peripheral operation fails, or if all the branches of the fifth are involved, the Gasserian 
ganglion must be removed or the sensory root of the fifth must be divided, as suggested by 
Frazier and Spiller. 
Removal of the Gasserian ganglion was suggested by J. Ewing Mears in 1884, and was first 
carried out by Rose in 1890. 
The method chiefly in vogue was devised by Hartley, and was first performed by him in 1891. 
An osteoplastic flap is made in front of the ear, the dura is exposed and lifted. Following Krause's 
advice, the third division is exposed and clamped. The second division is exposed and clamped. 
The nerves are loosened from their beds and then are rolled about the clamps. This twisting 
1 Carnochan, American Journal of the Medical Sciences, 1858, p. 136. 
2 Mears, Transactions of the American Surgical Association, vol. ii. p. 469, THE SIXTH OR ABDUCENT NE JIVE 
1043 
pulls out the ganglion intact along with the motor root, and also the sensory root from the 
pons. 
A difficulty in the Hartley operation is the danger of division of the meningeal artery. If 
this happens, the surgeon may be able to arrest bleeding and proceed with the operation. If 
the vessel is torn off at the foramen spinosum, it will be necessary to pack the wound and post- 
pone any further operative manipulation for forty-eight hours. 
Dr. Harvey Cushing has modified Hartley's operation by trephining the wall of the temporal 
fossa very low down. He opens the skull below the arch of the meningeal vessels, and thus avoids 
the meningeal at the foramen spinosum, and also the sulcus arteriosus of the parietal bone. 
After the removal of the ganglion, Professor Keen, in order to prevent undue inflammation of 
the eye, sews the eyelids of the affected side together, leaving a space open at each angle, and 
covers the eye with a watch-crystal. Boracic acid solution is flushed into the opening at the external 
angle at frequent intervals. The stitches are removed from the lid in from eight to ten days. 
The lingual (gustatory) nerve is occasionally divided with the view of relieving the pain in 
cancerous disease of the tongue. This may be done in that part of its course where it lies below 
and behind the last molar tooth. If a line is drawn from the middle of the crown of the last 
molar tooth to the angle of the jaw, it will cross the nerve, which lies about half an inch behind 
the tooth, parallel to the bulging alveolar ridge on the inner side of the body of the bone. If 
the knife is entered three-quarters of an inch behind and below the last molar tooth and carried 
down to the bone, the nerve will be divided. Hilton divided it opposite the second molar tooth, 
where it is covered only by the mucous membrane, and Lucas pulls the tongue forward and over 
to the opposite side, when the nerve can be seen standing out as a firm cord under the mucous 
membrane by the side of the tongue and can be easily seized with a sharp hook and divided or 
a portion excised. This is a simple enough operation on the cadaver, but when the disease is 
extensive and has extended to the floor of the mouth, as is generally the case when division of 
the nerve is thought of, the operation is not practicable. 
THE SIXTH OR ABDUCENT NERVE (N. ABDUCENS) (Fig. 669). 
The sixth or abducent nerve supplies the External rectus muscle. Its .super- 
ficial origin is by several filaments from the constricted part of the pyramid, close 
to the pons, or from the lower border of the pons itself, in the groove between this 
body and the medulla. Its deep origin is from the upper part of the floor of the 
fourth ventricle, close to the median line, beneath the eminentia teres (Fig. 613.) 
From the nucleus of the sixth nerve fibres pass through the posterior longitudinal 
bundle to the oculo-motor nucleus of the opposite side and into the third nerve, 
along which they are carried to the Internal rectus muscle. The External rectus 
of one eye and the Internal rectus of the other may therefore be said to receive 
their nerves from the same nucleus-a factor of great importance in connection 
with the conjugate movements of the eyeball, and one that may explain certain 
paralytic phenomena of the Recti muscles, which are often associated with lesions 
in the pons. 
"The nerve pierces the dura mater on the basilar surface of the sphenoid bone, 
runs through a notch immediately below the posterior clinoid process, and enters 
the cavernous sinus. It passes forward through the sinus, lying on the outer side 
of the internal carotid artery (Fig. 454). It enters the orbit through the sphenoid 
fissure, and lies above the ophthalmic vein, from which it is separated by a lamina 
of dura mater (Fig. 675). It then passes between the two heads of the External 
rectus muscle, and is distributed to that muscle on its ocular surface. 
Branches of Communication.-It is joined by several filaments from the 
carotid and cavernous plexuses, and by one from the ophthalmic nerve. 
Relations to Each Other of the Third, Fourth, Ophthalmic Division of the Fifth and 
Sixth Nerves as They Pass to the Orbit.-The third, the fourth, the ophthalmic 
division of the fifth, and the sixth nerves, as they pass to the orbit, bear a certain 
relation to each other in the cavernous sinus, at the sphenoidal fissure, and in the 
cavity of the orbit, which will now be described. 
In the Cavernous Sinus (Figs. 454 and 455) the third, fourth, and ophthalmic 
division of the fifth are placed on the outer wall of the sinus, in their numerical 1044 
THE NERVOUS SYSTEM 
order, both from above downward and from within outward. The sixth nerve 
lies at the outer side of the internal carotid artery. As these nerves pass for- 
ward to the sphenoidal fissure, the third and fifth nerves become divided into 
branches, and the sixth nerve approaches the rest, so that their relative position 
becomes considerably changed. 
In the Sphenoidal Fissure (Fig. 675) the fourth nerve and the frontal and 
lachrymal branches of the ophthalmic division of the fifth lie upon the same 
plane, the former being most internal, the latter external, and they enter the cavity 
of the orbit above the muscles. The remaining nerves enter the orbit between 
the two heads of the External rectus muscle. The superior division of the third 
nerve is the highest of these; beneath 
this lies the nasal branch of the 
ophthalmic nerve; then the inferior 
division of the third nerve; and the 
sixth nerve lowest of all. 
In the Orbit (Figs. 665 and 669) 
the fourth nerve and the frontal and 
lachrymal divisions of the ophthalmic 
nerve lie on the same plane immedi- 
ately beneath the periosteum, the 
fourth nerve being internal and rest- 
ing on the Superior oblique muscle, 
the frontal nerve resting on the Le- 
vator palpebne muscle, and the lach- 
rymal nerve on the External rectus 
muscle. Next in order comes the superior division of the third nerve, lying 
immediately beneath the Superior rectus muscle, and then the nasal branch of 
the ophthalmic nerve, crossing the optic nerve from the outer to the inner side 
of the orbit. Beneath these is found the optic nerve, surrounded in front by the 
ciliary nerves, and having the lenticular ganglion on its outer side, between it and 
the External rectus muscle. Below the optic nerve is the inferior division of the 
third nerve and the sixth nerve, which lies on the outer side of the orbit. 
Lachrymal. 
Frontal. 
4th. 
Superior division of 3d. 
Nasal. 
Inferior division of 3d 
6th. 
Ophthalmic vein. 
Fig. 675.-Relations of structures passing through 
the sphenoidal fissure. 
Surgical Anatomy.-It is often stated that the sixth nerve is more frequently involved in 
fractures of the base of the skull than any other of the cranial nerves. As a matter of fact, however, 
it is injured in only about 2 per cent, of cases of fracture of the skull (Putscher). Cases have been 
reported in which the nerve was actually ruptured. The nerve may be injured by traction, 
pressure of a blood clot, of a tumor, or of an arterio-venous aneurism. The result of paralysis of 
this nerve is internal or convergent squint. When injured so that its function is destroyed, there 
is, in addition to the paralysis of the External rectus muscle, often a certain amount of contrac- 
tion of the pupil, because some of the sympathetic fibres to the radiating muscle of the iris pass 
along with this nerve. 
THE SEVENTH OR FACIAL NERVE (N. FACIALIS) (Figs. 676, 677, 678). 
'The seventh or facial nerve or Portio Dura is the motor nerve of all the muscles 
of expression in the face, and of the Platysma and Buccinator; the muscles of 
the External ear; the posterior belly of the Digastric, and the Stylo-hyoid. Its 
chorda tympani branch is the nerve of taste for the anterior two-thirds of the 
tongue and the vaso-dilator nerve of the submaxillary and sublingual glands; its 
tympanic branch supplies the Stapedius. 
Its superficial origin is from the upper end of the medulla oblongata, in the 
groove between the olivary and restiform bodies. Its deep origin is from a nucleus 
situated in the floor of the fourth ventricle, beneath the superior fovea (Fig. 613). THE SEVENTH OR FACIAL NERVE 
1045 
rhe facial nucleus is deeply placed in the reticular formation of the lower part of 
the pons, a little external and ventral to the nucleus of the sixth nerve. From this 
origin the fibres pursue a curved course in the substance of the pons. They first 
pass backward and inward, and then turn upward and forward, forming the fas- 
ciculus teres, which produces an eminence, the eminentia teres, on the floor of the 
fourth ventricle, and finally bend sharply downward and outward around the upper 
end of the nucleus of origin of the sixth nerve, to reach their superficial origin 
between the olivary and restiform bodies. From the nucleus of the third nerve 
some fibres arise which descend in the posterior longitudinal bundle and join the 
facial just before it leaves the pons; these fibres are said to supply the anterior 
belly of the Occipito-frontalis, 
the Orbicularis palpebrarum, and 
the Corrugator supercilii, as these 
muscles have been observed to 
escape paralysis in lesions of the 
nucleus of the facial nerve. 
The auditory nerve {port io mol- 
lis) lies to the outer side of the 
facial nerve; and between the two 
is a small fasciculus, the pars in- 
termedia of Wrisberg (n. intermedins), which arises from the medulla and joins 
the facial nerve in the internal auditory meatus. The deep origin of the pars 
intermedia is from the upper end of the nucleus of the glosso-pharyngeal nerve, 
and at its emergence it is frequently connected with both nerves. 
The pars intermedia may be regarded as the sensory root of the facial nerve, 
analogous to the sensory root of the fifth, and its real nucleus of origin would then 
consist of the geniculate ganglion. 
The facial nerve, firmer, rounder, and smaller than the auditory, passes forward 
and outward upon the middle peduncle of the cerebellum, and enters the internal 
auditory meatus with the auditory nerve. Within the meatus the facial nerve 
lies in a groove along the upper and anterior part of the auditory nerve and the 
pars intermedia is placed between the two, and joins the inner angle of the geni- 
culate ganglion. Occasionally a few of its fibres pass into the auditory nerve. 
Beyond the ganglion its fibres are generally regarded as forming the chorda 
tympani. 
At the bottom of the meatus the facial nerve enters the aquaeductus Fallopii, 
and follows the course of that canal through the petrous portion of the temporal 
bone, from its commencement at the internal meatus to its termination at the' stylo- 
mastoid foramen (Figs. 49 and 676). It is at first directed outward between the 
cochlea and vestibule toward the inner wall of the tympanum; it then bends sud- 
denly backward and arches downward behind the tympanum to the stylo-mastoid 
foramen. At the point in the aqueduct of Fallopius where the nerve changes its 
direction (geniculum n. jacialis), it presents a reddish gangliform swelling, the genic- 
ulate ganglion (ganglion geniculi), which is also called the intumescentia ganglio- 
formis (Fig. 676). The geniculate ganglion receives a branch from the vestibular 
division of the auditory nerve, which probably carries fibres of the pars intermedia. 
On emerging from the stylo-mastoid foramen the facial nerve runs forward in the 
substance of the parotid gland, crosses the external carotid artery, and divides 
behind the ramus of the lower jaw into two primary branches, temporo-facial 
and cervico-facial, from which numerous offsets are distributed over the side of 
the head, face, and upper part of the neck, supplying the superficial muscles 
in these regions. As the primary branches and their offsets diverge from each 
other, they present somewhat the appearance of a bird's claw; hence the name of pes 
anserinus is given to the divisions of the facial nerve in and near the parotid gland. 
External petrosal.- 
Small superficial petrosal" 
Large superficial petrosal.' 
Intumescentia ganglioformis. 
Fig. 676.-The course and connection of the facial nerve 
in the temporal bone. THE NERVOUS SYSTEM 
1046 
Branches of Communication (Fig. 677).-The communications of the facial 
nerve may be thus arranged: 
With the auditory nerve. The pars 
intermedia, which is between the 
facial and auditory, gives branches 
to both. The branch given to the 
auditory accompanies it for a certain 
distance, and then departs from it to 
join the geniculate ganglion. 
In the internal auditory meatus 
With the auditory as explained above. 
With Meckel's ganglion by the large 
superficial petrosal nerve. 
With the otic ganglion by the small 
superficial petrosal nerve. 
With the sympathetic on the middle 
meningeal artery by the external 
superficial petrosal nerve. 
From the geniculate ganglion 
Tn the Fallopian aqueduct 
With the auricular branch of the pneu- 
mogastric. 
With the glosso-pharyngeal. 
With the pneumogastric. 
With the auricularis magnus. 
With the auriculo-temporal. 
At its exit from the stylo-mastoid 
foramen 
Behind the ear 
On the face 
With the small occipital. 
With the three divisions of the fifth. 
In the neck 
With the superficial cervical. 
In the internal auditory meatus some minute filaments pass between the facial 
and auditory nerves. 
Opposite the hiatus Fallopii, the gangliform enlargement on the facial nerve 
communicates with Meckel's ganglion by means of the large superficial petrosal 
nerve, which forms its motor root; with the otic ganglion, by the small superficial 
petrosal nerve; and with the sympathetic filaments accompanying the middle 
meningeal artery, by the external petrosal nerve (Bidder). From the gangliform 
enlargement, according to Arnold, a twig is sent back to the auditory nerve. Just 
before the facial nerve emerges from the stylo-mastoid foramen it generally receives 
a twig of communication from the auricular branch of the pneumogastric. 
After its exit from the stylo-mastoid foramen, it sends a twig to the glosso- 
pharyngeal, another to the pneumogastric nerve, and communicates with the great 
auricular branch of the cervical plexus, with the auriculo-temporal branch of the 
inferior maxillary nerve in the parotid gland, with the small occipital nerve 
behind the ear, on the face with the terminal branches of the three divisions of 
the fifth, and in the neck with the transverse cervical. 
Branches of Distribution (Fig. 677).-The branches of distribution of the 
facial nerves may be thus arranged: 
Within the aquaeductus Fallopii 
Tympanic, to the Stapedius muscle. 
Chorda tympani. 
At its exit from the stylo-mastoid 
foramen 
Posterior Auricular. 
Digastric. 
Stylo-hyoid. 
Tempo ro-facial 
Temporal. 
Malar. 
Infraorbital. 
On the face 
Buccal. 
Supramaxillary. 
Infram axillary. 
Cervico-facial THE SEVENTH OR FACIAL NERVE 
1047 
The branches of the two terminal divisions form the parotid plexus (plexus paro- 
tideus). 
The Tympanic Branch (n. stapedius) (Fig. 677).-The tympanic branch arises 
from the nerve opposite the pyramid; it passes through a small canal in the 
pyramid and supplies the Stapedius muscle. 
The Chorda Tympani (Figs. 671, 676, and 677).-The chorda tympani is given 
off from the facial as it passes vertically downward at the back of the tympanum, 
about a quarter of an inch before its exit from the stylo-mastoid foramen. It 
passes from below upward and forward in a distinct canal, and enters the cavity 
of the tympanum through an aperture (iter chordae posterius) on its posterior wall 
between the opening of the mastoid cells and the attachment of the membrana 
tympani, and becomes invested with mucous membrane. It passes forward through 
the cavity of the tympanum, between the fibrous and mucous layers of the mem- 
brana tympani, and over the handle of the malleus, emerging from that cavity 
To Auditory-' 
Portio 
.Intermedia 
Geniculate 
Ganglion- 
Facial 
Ext.Superfi cial 
Petrosal 
Vidian. 
Tympanic of 
Glosso-pharyngeal 
Large Deep Petrosa I 
Com.with 
Arnold's 
Nerve 
-.Stapedius 
Otic Ganglion 
Com.Branch 
Lingual 
Post 
Auricular 
From 
Auricula-fempora I 
Temporo-facial 
Temporal 
Malar 
Infraorbital 
Digastric 
Stylo-hyoid*' 
Buccal 
Cervico-facial 
Supramaxilla ry 
Fig. 677.-Plan of the facial nerve. 
In framaxillary 
through a foramen at the inner end of the Glaserian fissure, which is called the 
canal of Huguier (iter chordae anterius). It then descends between the two 
Pterygoid muscles, meets the lingual nerve at an acute angle, and accompanies 
it to the submaxillary gland; part of it then joins the submaxillary ganglion; the 
rest is continued onward through the muscular substance of the tongue to the 
mucous membrane covering its anterior two-thirds. A few of its fibres probably 
pass through the submaxillary ganglion to the sublingual gland. Before joining 
the lingual nerve it receives a small communicating branch from the otic ganglion. 
As already stated, the chorda tympani nerve is by many regarded as the con- 
tinuation of the pars intermedia of Wrisberg. 
The Posterior Auricular Nerve (n. auricularis posterior) (Figs. 634,677, and 678).- 
The posterior auricular nerve arises close to the stylo-mastoid foramen, and passes 
upward in front of the mastoid process and between the mastoid process and the 
external ear, where it is joined by a filament from the auricular branch of the 
pneumogastric (Fig. 684), and communicates with the mastoid branch of the great THE NERVOUS SYSTEM 
1048 
auricular and with the small occipital. As it ascends between the external auditory 
meatus and the mastoid process it divides into two branches, the auricular and 
the occipital branches. 
The Auricular Branch supplies the Retrahens auriculam and the small muscles 
on the cranial surface of the pinna. 
The Occipital Branch (ramus occipitalis}, the larger, passes backward along the 
superior curved line of the occipital bone, and supplies the occipital portion of the 
()ccipito-f rontalis. 
The Digastric Branch of the Facial Nerve (ramus digastricus}.-The digastric 
branch usually arises by a common trunk with the Stylo-hyoid branch; it divides 
into several filaments, which supply the posterior belly of the Digastric; one of 
these perforates that muscle to join the glosso-pharyngeal nerve (ramus anasto- 
moticus cum n. glossopharyngeo}. 
Terminations 
of supratrochlear. 
of infratrochlear 
X of nasal. 
Fig. 678. The nerves of the scalp, face, and side of the neck. 
The Stylo-hyoid Branch (ramus stylohyoideus).-The stylo-hyoid branch is a 
long, slender branch, which passes inward, entering the Stylo-hyoid muscle about 
its middle. 
The Temporo-facial Division (Figs. 677 and 678).-The temporo-facial, the larger 
of the two terminal branches of the facial, passes upward and forward through THE SEVENTH OR FACIAL NERVE 
1049 
the parotid gland, crosses the external carotid artery and temporo-maxillary vein, 
and passes over the neck of the condyle of the jaw, being connected in this situation 
with the auriculo-temporal branch of the inferior maxillary nerve, and divides 
into branches which are distributed over the temple and upper part of the face; 
these are divided into three sets-temporal, malar, and infraorbital. 
The Temporal Branches (rami temporales) cross the zygoma to the temporal 
region, supplying the Attrahens and Attollens auriculam muscles, and join with 
the temporal branch of the temporo-malar division of the superior maxillary, 
and with the auriculo-temporal branch of the inferior maxillary. The more ante- 
rior branches supply the frontal portion of the Occipito-frontalis, the Orbicularis 
palpebrarum, and Corrugator supercilii muscles, joining with the supraorbital 
and lachrymal branches of the ophthalmic. 
The Malar Branches (rami zygomatici) pass across the malar bone to the outer 
angle of the orbit. Where they supply the Orbicularis palpebrarum muscle, join- 
ing with filaments from the lachrymal nerve; others supply the lower eyelid, 
joining with filaments of the malar branch (subcutaneous malae) of the superior 
maxillary nerve. 
The Infraorbital Branches (rami buccales), of larger size than the rest of the malar 
branches, pass horizontally forward to be distributed between the lower margin of 
the orbit and the mouth. The superficial branches run beneath the skin and 
above the superficial muscles of the face, which they supply; some branches are 
distributed to the Pyramidalis nasi, joining at the inner angle of the orbit with the 
infratrochlear and nasal branches of the ophthalmic. The deep branches pass 
beneath the Zygomatici and the Levator labii superioris, supplying the Levator 
anguli oris, the Levator labii superioris alaeque nasi and the small muscles of the 
nose, and form a plexus, infraorbital plexus, by joining with the branches of the 
infraorbital branch of the superior maxillary nerve and the buccal branches of 
the cervico-facial. 
The Cervico-facial Division.-The cervico-facial division of the facial nerve 
passes obliquely downward and forward through the parotid gland, crossing the 
external carotid artery. In this situation it is joined by branches from the great 
auricular nerve. Opposite the angle of the lower jaw it divides into branches 
which are distributed on the lower half of the face and upper part of the neck. 
These may be divided into three sets-buccal, supram axillary, and inframaxillary. 
The Buccal Branches (rami buccales) cross the Masseter muscle. They supply 
the Buccinator and Orbicularis oris, and join with the infraorbital branches of 
the teinporo-facial division of the nerve, and with filaments of the buccal branch 
of the inferior maxillary nerve. 
The Supramaxillary or Supramandibular Branch (ramus marginalis mandibulae) 
passes forward beneath the Platysma and Depressor anguli oris, supplying the 
muscles of the lower lip and chin, and communicating with the mental branch of 
the inferior dental nerve. 
The Inframaxillary, Inframandibular or Cervical Branch (ramus colli) runs for- 
ward beneath the Platysma, and forms a series of arches across the side of the 
neck over the suprahyoid region. A branch descends vertically to join with the 
superficial cervical nerve from the cervical plexus; others supply the Platysma. 
Surgical Anatomy. -The facial nerve is more frequently paralyzed than any of the other 
of the cranial nerves. The paralysis may depend either upon (1) central causes-i. e., blood-clots 
or intracranial tumors pressing on the nerve before its entrance into the internal auditory meatus. 
It is also one of the nerves involved in bulbar paralysis. Or (2) it may be paralyzed in its pass- 
age through the petrous bone by damage due to middle-ear disease or by fractures of the base. 
Or (3) it may be affected at or after its exit from the stylo-mastoid foramen. This is commonly 
known as Bell's paralysis. It may be due to exposure to cold or to injury of the nerve, either 
from accidental wounds of the face or during some surgical operation, as removal of parotid 
tumors, opening of abscesses, or operations on the lower jaw. 1050 
THE NERVOUS SYSTEM 
When the cause is central, the sixth nerve is usually paralyzed as well, and there is also hemi- 
plegia on the opposite side. In these cases the electric reactions are the same as in health; 
whereas, when the paralysis is due to a lesion in the course of the nerve, the reactions of degenera- 
tion develop. When the nerve is paralyzed in the petrous bone, in addition to the paralysis of the 
muscles of expression, there is loss of taste in the anterior part of the tongue, and the patient is 
unable to recognize the difference between bitters and sweets, acids and salines, from involvement 
of the chorda tympani. The mouth is dry, because the salivary glands are not secreting; the sense 
of hearing is affected from paralysis of the Stapedius, but there is not hemiplegia. When the 
cause of the paralysis is from fracture of the base of the skull, the auditory nerve and the petrosal 
nerves, which are connected with the intumescentia ganglioformis, are also involved. When the 
injury to the nerve is after its exit from the stylo-mastoid foramen, all the muscles of expression, 
except the Levator palpebrae, together with the posterior belly of the Digastric and Stylo-hyoid, 
are paralyzed. There is smoothness of the forehead, and the patient is unable to frown; the 
eyelids cannot be closed, and the lower lid droops, so that the punctum is no longer in contact 
with the globe, and the tears run down the cheek; there is smoothness of the cheek and loss of 
the naso-labial furrow; the nostril of the paralyzed side cannot be dilated; the mouth is drawn 
to the sound side, and there is inability to whistle; food collects between the cheek and gum 
from paralysis of the Buccinator. 
The facial nerve is at fault in cases of so-called histrionic spasm, which consists in an almost 
constant and uncontrollable twitching of the muscles of the face. This twitching is sometimes 
so severe as to cause great discomfort and annoyance to the patient and to interfere with sleep, 
and for its relief the facial nerve has been stretched. The operation is performed by making 
an incision behind the ear from the root of the mastoid process to the angle of the jaw. The 
parotid is turned forward, and the dissection carried along the anterior border of the Sterno- 
mastoid muscle and mastoid process until the upper border of the posterior belly of the Digas- 
tric is found. The nerve is parallel to this on about a level with the middle of the mastoid process. 
When found, the nerve may be stretched by passing a blunt hook beneath it and pulling it 
forward and outward. Too great force must not be used, for fear of permanent injury to the 
nerve. In facial palsy of extracerebral origin it may be advisable to expose the nerve, cut it 
across, and anastomose the distal end of the paralyzed nerve to the spinal accessory, or, better, 
to the hypoglossal nerve (facio-accessory anastomosis or facio-hypoglossal anastomosis). The 
idea was first proposed by Ballance, and has been put in practice by Ballance and Stewart, 
Keen, Cushing, Faure, Kennedy and others. 
THE EIGHTH OR AUDITORY NERVE fN. ACUSTICUS) (Fig. 679). 
The eighth or auditory nerve or Portio Mollis is the special nerve of the sense 
of hearing, being distributed exclusively to the internal ear. It is soft in texture; 
hence the name, portio mollis, and is destitute of neurilemma. 
The Origin of the Eighth Nerve.-The eighth nerve consists of two sets of 
fibres, which, although differing in their central connections, are both concerned in 
the transmission of afferent impulses from the internal ear to the medulla and pons, 
and from there, by means of new fibres which arise from collections of gray matter 
in these structures, to the cerebrum and cerebellum. One set of fibres forms the 
vestibular root, another set forms the cochlear root of th? nerve. At its con- 
nection with the brain the eighth nerve occupies the groove between the pons 
and medulla, where it is situated between th? restiform body, which is behind, 
and the seventh nerve, which is in front. 
Vestibular, Nexal or Ventral Root (radix vestibularis) (Fig. 613).-Thefibres of this 
root enter the medulla to the inner side of those of the cochlear root, and pass 
between the restiform body, which is to their outer side, and the inferior root of the 
fifth, which lies to their inner side. They then divide into an ascending and a 
descending set. 'The fibres of the latter end by arborizing around the cells of the 
internal nucleus, which is situated in the trigonum acustici in the floor of 
the fourth ventricle. The ascending fibres either end in the same manner or in the 
external nucleus, which is situated to the outer side of the trigonum acustici and 
farther from the ventricular floor. It is described as consisting of two parts, an 
inner, the nucleus of Deiters, and an outer, the nucleus of Bechterew. Some of the 
axones of the cells of the external nucleus, and possibly also of the internal nucleus, 
are continued upward through the restiform body to the roof nuclei of the opposite THE EIGHTH OR AUDITORY NERVE 
1051 
side of the cerebellum, to which also are prolonged other fibres of the vestibular 
root without undergoing a relay in the nuclei of the medulla. A second set of 
fibres from the internal and external nuclei end partly in the tegmentum, while 
the remainder ascend in the posterior longitudinal bundle to arborize around the 
nuclei of the oculo-motor nerve. 
Cochlear, Dorsal or Lateral Root (radix cochlearis) (Fig. 613).-This part of the 
nerve is placed externally to the vestibular root. Its fibres end in two nuclei, 
one of which, the accessory nucleus, lies immediately in front of the restiform 
body; the other, the tuberculum acusticum, somewhat to its outer side. 
The striae acusticae or medullary striae are the axones of the cells of the tuber- 
culum acusticum. They pass backward and inward over the restiform body, and 
across the floor of the fourth ventricle toward the middle line. Here they dip into 
the substance of the pons, to end around the cells of the superior olive of the same 
or opposite side, There are, however, other fibres, and these are both direct and 
crossed, which do not arborize around the tegmental nuclei, but pass into the lat- 
STAPES 
Fig. 679.-Distribution of the auditory nerve. (Semidiagrammatic.) (Testut.) 
eral fillet. The cells of the accessory nucleus give origin to fibres which pass trans- 
versely in the pons and constitute the trapezium. The description given as to the 
mode of ending of the striae acusticae is applicable to that of the trapezoid fibres- 
viz., around the cells of the superior olive or of the trapezoid nucleus (which lies 
ventral to the olive) of the same or opposite side, while others, crossed or uncrossed, 
pass directly into the lateral fillet. 
If the further connections of the cochlear nerve of one side, say the left, are 
considered, it is found that they lie to the outer side of the main sensory tract, the 
fillet, and are therefore termed the lateral fillet. The fibres comprising the left 
lateral fillet arise in the superior olive or trapezoid nucleus of the same or opposite 
side, while others are the uninterrupted fibres already alluded to, and these are 
either crossed or uncrossed, the former being the axones of the cells of the right 
accessory nucleus or of the cells of the right tuberculum acusticum, while the latter 
are derived from the same cells of the left side. In the upper part of the fillet 
there is a collection of nerve-cells, the nucleus of the fillet (fila anastomotica), around THE NERVOUS SYSTEM 
1052 
the cells of which some of the fibres arborize, and from the cells of which axones 
originate to continue upward the tract of the lateral fillet. The ultimate ending 
of the left lateral fillet is partly in the quadrigeminal bodies of the same or opposite 
Fig. 680.-Diagram of the central auditory tract ^direct or root-fibre system): N.c., cochlear nerve; F.a., 
acoustic tubercle; v.K., ventral nucleus; c.t., trapezoid body; o.O., o.O., superior olives; R., raphe; Schl.K., 
nucleus of the lemniscus; o. V.. pregeminum; Ri., cortex. (Rauber, after Held.) 
Fig. 081 .-Diagram of the central auditory tract (system of the second order): N.c., cochlear nerve; v.K., 
ventral nucleus; c.t., trapezoid body; R., raph6; T.K., trapezoid nucleus; o.O., superior olive; T.a., acoustic 
tubercle; St.a., acoustic striae; Z.S.K., nucleus of the lateral lemniscus; Ba., prepeduncle; Bak., decussation of 
the prepeduncle; o. V., pregeminum; n. V., post-geminum; Ri., cortex; Rb., cortical tract. (Rauber, after Held.) THE EIGHTH OR AUDITORY NERVE 
1053 
side, while the remainder of the fibres ascend in the posterior limb of the internal 
capsule to reach the first and perhaps the second left temporal convolution. 
The auditory nerve contains a few afferent fibres which arise in the quadrigem- 
inal bodies, the nucleus of the lateral fillet, trapezoid nucleus, and superior olive. 
The auditory nerve after leaving the medulla passes forward across the poste- 
rior border of the middle peduncle of the cerebellum, in company with the facial 
nerve, from which it is partly separated by a small artery, the auditory. It then 
enters the internal auditory meatus with the facial nerve. In the meatus it divides 
into its two branches, the inferior or cochlear trunk (n. cochleae) and the superior or 
vestibular trunk (n. vestibuli). The cochlear trunk is a continuation of the cochlear 
root, gives branches to the macula acustica of the saccule, and to the ampulla of 
the posterior semicircular canal, and then passes through the lamina cribrosa 
to the labyrinth. The cochlear nerve is distributed to the modiolus and osseous 
spiral lamina, and is finally distributed to the organ of Corti. The vestibular 
Fig. 682.-Diagram of the central auditory tract (recurrent system): V.K., ventral nucleus; c.t., trapezoid 
body; R., raph6; TK., trapezoid nucleus; o.O., superior olive; Ta., acoustic tubercle; Sta., acoustic striae; S.K., 
nucleus of the lemniscus; o. V., pregeminum; n. V., post-geminum; Ri., coterx. (Rauber, after Held.) 
trunk is a continuation of the vestibular root. In the internal meatus it receives 
fibres of the pars intermedia and gives a branch to the geniculate ganglion of 
the facial nerve (Cunningham). It divides into three branches, which pass 
through the lamina cribrosa and are distributed, one to the macula acustica of 
the utricle and the ampulla, one to the superior semicircular canal, and one to 
the external semicircular canal. There is a ganglion on the vestibular nerve 
called the vestibular ganglion (ganglion vestibidare), and a ganglion on the cochlear 
nerve, the ganglion of Corti (ganglion spirale). The fibres of the auditory nerve 
proper arise in these ganglia; the vestibular fibres in the ganglion vestibulare; 
the cochlear fibres in the ganglion spirale. 
The Auditory Paths (Figs. 680, 681, and 682).-There are two auditory 
paths, the cochlear or central auditory path and the vestibular path. 
The Cochlear Path.-The cochlear path conducts impulses of hearing. Such 
impulses pass from the organ of Corti to the ganglion of Corti (ganglion spirale) 
and then by the cochlear fibres to the cochlear nucleus in the medulla. The 
path from the nucleus to the cortical auditory centre is described as follows 1054 
THE NERVOUS SYSTEM 
by Santee.1 Impulses from the cochlear nucleus "run either lateral and dorsal 
to the restiform body and cross to the opposite side through the acustic striae 
and trapezium, or they run medial to the restiform body and enter at once into 
the trapezium. By either course they reach the lateral fillet, and chiefly the oppo- 
site one. The lateral fillets conduct the impulses to the inferior quadrigeminal 
bodies; the inferior brachia to the internal geniculate bodies, and the acustic radia- 
tion to the third and fourth fifths of the superior temporal and to the transverse 
temporal gyri of the cerebrum." 
The Vestibular Path.-The vestibular path conducts impulses of equilibrium. 
Impulses from the semicircular canals, utricle and saccule pass by way of the 
vestibular nerve to the vestibular nuclei in the floor of the fourth ventricle and a 
spinal nucleus of undetermined situation. From these nuclei impulses pass to the 
nuclei in the opposite side of the cerebellum by one of two routes. Either by the 
opposite medial fillet and fibres of the systems of Flechsig or through the acustico- 
cerebellar tract and fibres of the vestibular nerve in the restiform body to the 
opposite cerebellum (nucleus fastigii,. nucleus globosus, corpus dentatum, and 
cerebellar cortex).2 From the cerebellum impulses pass along the superior 
peduncle to "the red nucleus and optic thalamus of both sides and thence to the 
cortex. They may excite in the cerebellum impulses of equilibration, which 
descend to the motor nuclei of spinal nerves in the anterior horns of gray matter 
by way of the antero-lateral descending cerebellar tracts" (Santee). 
Surgical Anatomy.-The auditory nerve is frequently injured, together with the facial nerve, 
in fractures of the middle fossa of the base of the skull implicating the internal auditory meatus. 
The nerve may be either torn across, producing permanent deafness, it may be bruised or it may 
be pressed upon by extravasated blood or inflammatory exudation, when the deafness will in all 
probability be temporary. The nerve may also be injured by violent blows on the head without 
fracture, and deafness may follow loud explosions of dynamite, etc., probably from some lesion 
of this nerve, which is more liable to be injured than the other cranial nerves on account of 
its structure. The test that the nerve is destroyed and that the deafness is not due to some 
lesion of the auditory apparatus is obtained by placing a vibrating tuning-fork on the head. 
The vibrations will be heard in cases where the auditory apparatus is at fault, but not in cases 
of destruction of the auditory nerve. 
THE NINTH OR GLOSSO-PHARYNGEAL NERVE (N. GLOSSOPHARYNGEUS) 
(Figs. 683, 684, 685). 
The ninth or glosso-pharyngeal nerve is distributed, as its name implies, to 
the tongue and pharynx, being the nerve of ordinary sensation to the mucous 
membrane of the pharynx, fauces, and tonsil; and the 
nerve of taste to all parts of the tongue to which it is 
distributed. 
Its superficial origin is by three or four filaments, 
closely connected together, from the upper part of the 
medulla oblongata, in the groove between the olivary 
and restiform body (Fig. 683). Its deep origin (Fig. 
613) may be traced through the fasciculi of the lateral 
tract to three different sources: (1) some of the fibres 
may be traced to a nucleus of gray matter at the lower 
part of the floor of the fourth ventricle beneath the 
inferior fovea; (2) others may be traced downward into 
the funiculus solitarius, a rounded bundle of fibres in the 
lower part of the medulla, commencing immediately above the decussation of the 
pyramids (these fibres have not been distinctly traced to cells); (3) a third set of 
Jugular Gangl. 
Petrous Gangl 
Tympanic br. 
GIomo- 
Pharyngeal 
Spinal Accessory 
Pneumo-gastric 
Fig. G83.-Origin, ganglia, and 
communication of the ninth, tenth, 
and eleventh cranial nerves. 
1 Anatomy of the Brain and Spinal Cord. 2 Santee, loc. cit. THE NINTH OR GLOSSO-PHARYNGEAL NERVE 
1055 
Fig 684.-Plan of the glosso-pharyngeal, pneumogastric, and spinal accessory nerves. (After Flower.) 1056 
THE NERVOUS SYSTEM 
fibres takes origin from the cells of the nucleus ambiguus. 'This nucleus is 
situated Some distance from the floor of the fourth ventricle and lies slightly 
internal to the inferior fovea. It gives origin to the motor branches of the glosso- 
pharyngeal and vagus, and to the bulbar part of the spinal accessory. The real 
origin of the sensory fibres of the glosso-pharyngeal must be looked for in the 
jugular and petrosal ganglia which are developed from the neural crest. 
From its superficial origin it passes outward across the flocculus, and leaves the 
skull at the central part of the jugular foramen, in a separate sheath of the dura 
mater, external to and in front of the pneumogastric and spinal accessory nerves 
(Fig. 685). In its passage through the jugular foramen it grooves the lower 
border of the petrous portion of the temporal bone, and at its exit from the skull 
passes forward between the jugular vein and internal carotid artery, and descends 
in front of the latter vessel, and beneath the styloid process of the temporal bone 
and the muscles connected with it, to the lower border of the Stylo-pharyngeus 
muscle. The nerve now curves inward, forming an arch on the side of the neck, 
and lying upon the Stylo-pharyngeus muscle and the Middle constrictor of the 
pharynx. It then passes beneath the Hyoglossus muscle, and is finally distributed 
to the mucous membrane of the fauces and base of the tongue, and the mucous 
glands of the mouth and tonsil. 
In passing through the jugular foramen the nerve presents, in succession, two 
gangliform enlargements. The superior and smaller is called the jugular ganglion; 
the inferior and larger, the petrous ganglion or the ganglion of Andersch. 
The Superior or Jugular Ganglion (Ganglion Superius n. Glossopharyngei) 
(Fig. 684). 
The superior or jugular ganglion is situated in the upper part of the groove in 
which the nerve is lodged during its passage through the jugular foramen. It is 
of very small size, and involves only the lower part of the trunk of the nerve. 
It is usually regarded as a segmentation from the lower ganglion. 
The Inferior or Petrous Ganglion (Ganglion Petrosum n. Glossopharyngei) 
(Figs. 683 and 684). 
The inferior or petrous ganglion is situated in a depression in the lower border 
of the petrous portion of the temporal bone; it is larger than the superior ganglion 
and involves the whole of the fibres of the nerve. From this ganglion arise 
those filaments which connect the glosso-pharyngeal with the pneumogastric and 
sympathetic nerves. 
Branches of Communication (Fig. 684).-The branches of communication 
are with the pneumogastric, sympathetic, and facial. 
The branches to the pneumogastric are two filaments, arising from the petrous 
ganglion, one of which passes to the auricular branch of the pneumogastric, and 
one to the upper ganglion of the pneumogastric. 
The branch to the sympathetic, also arising from the petrous ganglion, is con- 
nected with the superior cervical ganglion. 
The branch of communication with the facial perforates the posterior belly of 
the Digastric muscle. It arises from the trunk of the nerve below the petrous 
ganglion, and joins the facial just after its exit from the stylo-mastoid foramen. 
Branches of Distribution (Fig. 684).-The branches of distribution are the 
tympanic, carotid, pharyngeal, muscular, tonsillar, and lingual. 
The Tympanic Branch or Jacobson's Nerve (n. tympan icus\- The tympanic branch 
or Jacobson's nerve arises from the petrous ganglion, and enters a small bony 
canal in the lower surface of the petrous portion of the temporal bone, the lower THE TENTH OR PNEUMOGASTRIC NERVE 
1057 
opening of which is situated on the bony ridge which separates the carotid canal 
from the jugular fossa. It ascends to the tympanum, enters that cavity by an 
aperture in its floor close to the inner wall, and divides into branches which are 
contained in grooves upon the surface of the promontory. These branches form 
a tympanic plexus {plexus tympanicus). This plexus gives off (1) the greater 
part of the small superficial petrosal nerve (Fig. 677); (2) a branch to join the 
great superficial petrosal nerve; and (3) branches to the tympanic cavity, all of 
which will be described in connection with the anatomy of the ear. 
The Carotid Branches (n. caroticotympanicus superior and n. caroticotympanicus 
inferior).-The carotid branches descend along the trunk of the internal carotid 
artery as far as its commencement, communicating with the pharyngeal branch 
of the pneumogastric and with branches of the sympathetic. 
The Pharyngeal Branches (rami pharyngei) (Fig. 684).-The pharyngeal branches 
are three or four filaments which unite opposite the Middle constrictor of the 
pharynx with the pharyngeal branches of the pneumogastric and sympathetic 
nerves to form the pharyngeal plexus, branches from which perforate the muscular 
coat of the pharynx to supply the muscles and mucous membrane. 
The Muscular Branch (ramus stylopharyngeus).-The muscular branch is dis- 
tributed to the Stylo-pharyngeus muscle. 
The Tonsillar Branches (rami tonsillares).-The tonsillar branches supply the 
tonsil, forming a plexus (circulus tonsillaris) around this body, from which 
branches are distributed to the soft palate and fauces, where they communicate 
with the palatine nerves. 
The Lingual Branches (rami linguales).-The lingual branches are two in num- 
ber: one supplies the circumvallate papillae and the mucous membrane covering 
the surface of the base of the tongue; the other perforates its substance, and 
supplies the mucous membrane and follicular glands of the posterior one-third 
of the tongue and communicates with the lingual nerve. 
The Gustatory Path.-The impressions of taste reach the glosso-pharyngeal 
nucleus in the medulla in two ways. From the posterior one-third of the tongue 
and from the palate they reach the nucleus by the ninth nerve. From the anterior 
two-thirds of the tongue impulses of taste are conveyed by the chorda tympani 
and pars intermedia. From the glosso-pharyngeal nucleus gustatory impressions 
pass by way of the medial fillet to the optic thalamus of the opposite side, and 
from the optic thalamus through the inferior lamina of the internal capsule to the 
gyrus hippocampi, where the cortical gustatory centre is situated. 
Surgical Anatomy.-In jury may produce hemorrhage about the roots of the nerve. Bergmann 
reported such a ease. The patient died from oedema of the glottis after presenting evidences 
of disorder of speech and difficulty in swallowing. 
THE TENTH OR PNEUMOGASTRIC NERVE (N. VAGUS) (Figs. 683, 684, 685). 
The tenth or pneumogastric nerve has a more extensive distribution than any 
of the other crainal nerves, passing through the neck and thorax to the upper part 
of the abdomen. It is composed of both motor and sensory fibres. It supplies 
the organs of voice and respiration with motor and sensory fibres, and the pharynx, 
oesophagus, stomach, and heart with motor fibres. Its superficial origin (Fig. 683) 
is by eight or ten filaments from the groove between the olivary and the restiform 
body below the glosso-pharyngeal; its deep origin (Fig. 613) may be traced through 
the fasciculi of the medulla to a nucleus of gray matter, the nucleus vagi, at the lower 
part of the floor of the fourth ventricle beneath the ala cinerea below and continu- 
ous with the nucleus of origin of the glosso-pharyngeal. Tn addition to this a few 
fibres pass into the funiculus solitarius, and others into the nucleus ambiguus or 1058 
THE NERVOUS SYSTEM 
accessory vagal nucleus. The real origin of the sensory fibres of the vagus is to be 
found in the cells of the ganglia on the nerve-viz., the ganglion of the root and 
the ganglion of the trunk. The 
filaments become united and 
form a flat cord, which passes 
outward beneath the flocculus 
to the jugular foramen, through 
which it emerges from the cran- 
ium (Fig. 685). In passing 
through this opening the pneu- 
mogastric accompanies the spi- 
nal accessory, being contained in 
the same sheath of dura mater 
with it, a membranous septum 
separating them from the glosso- 
pharyngeal, which lies in front 
(Fig. 685). The nerve in this 
situation presents a well-marked 
ganglionic enlargement, which 
is called the superior ganglion, 
jugular ganglion, or the ganglion 
of the pneumogastric; to it the 
accessory part of the spinal ac- 
cessory nerve is connected by 
one or two filaments. After the 
exit of the nerve from the jugular 
foramen the nerve is joined by 
the accessory portion of the 
spinal accessory, and enlarges 
into a second gangliform swell- 
ing, called the inferior ganglion 
or the ganglion of the trunk of 
the nerve, through which the 
fibres of the spinal accessory 
pass unchanged, being prin- 
cipally distributed to the pha- 
ryngeal and superior laryngeal 
branches of the vagus; but some 
of the filaments from it are con- 
tinued into the trunk of the 
vagus below the ganglion, to be 
distributed with the recurrent 
laryngeal nerve, and probably 
also with the cardiac nerves. 
The vagus nerve passes verti- 
cally down the neck within the 
sheath of the carotid vessels lying 
between the internal carotid 
artery and the internal jugular 
vein as far as the thyroid cartil- 
age, and then between the same 
vein and the common carotid to the root of the neck (Fig. 685). brom here 
the course of the nerve differs on the two sides of the body. 
On the right side (Fig. 685) the nerve passes across the subclavian artery between 
Glosso-pharyngeal. 
Pneumogastric. 
Spinal accessory. 
■Superior laryngeal 
nerve. 
'External laryngeal. 
Inferior laryngeal. 
•Cardiac. 
Pulmonarj}' 
bri. 
Fig. 685.-Course and distribution of the ninth, tenth, and 
eleventh nerves. THE TENTH OR PNEUMOGASTRIC NERVE 
1059 
it and the right innominate vein, and descends by the side of the trachea to the back 
part of the root of the lung, where it spreads out in a plexiform network, the pos- 
terior pulmonary plexus (plexus pulmonalis posterior), from the lower part of which 
two cords descend upon the oesophagus, on which tube they divide, forming, with 
branches from the opposite nerve, the oesophageal plexus {plexus gulae); below, these 
branches are collected into a single cord, which runs along the back part of the 
oesophagus, enters the abdomen, and is distributed to the posterior surface of 
the stomach, joining the left side of the solar plexus, and sending filaments to the 
splenic plexus and a considerable branch to the cceliac plexus. 
On the left side the pneumogastric nerve enters the chest between the left carotid 
and subclavian arteries, behind the left innominate vein. It crosses the arch of 
the aorta and descends behind the root of the left lung, forming the anterior pul- 
monary plexus (plexus pulmonalis anterior), and along the anterior surface of the 
oesophagus, where it unites with the nerve of the right side in forming the plexus 
gulae. It passes to the stomach, distributing branches over the anterior surface of 
that viscus, some extending over the great cul-de-sac, and others along the lesser 
curvature. Filaments from these branches enter the gastro-hepatic omentum and 
join the hepatic plexus. 
The Ganglion of the Root of the Pneumogastric Nerve (Ganglion Jugulare) 
(Fig. 684). 
The ganglion of the root or the jugular ganglion is of a grayish color, circular 
in form, about two lines in diameter, and resembles the ganglion on the large 
root of the fifth nerve. 
Connecting Branches.-To this ganglion the accessory portion of the spinal 
accessory nerve is connected by several delicate filaments; it also has a communi- 
cating twig with the petrous ganglion of the glosso-pharyngeal, with the facial 
nerve by means of its (the ganglion's) auricular branch, and with the sympa- 
thetic by means of an ascending filament from the superior cervical ganglion. 
The Ganglion of the Trunk of the Pneumogastric Nerve (Ganglion Nodosum) 
(Fig. 684). 
The ganglion of the trunk or the inferior ganglion is a plexiform cord, cylindrical 
in form, of a reddish color, and about an inch in length; it involves the whole of 
the fibres of the nerve, and passing through it is the accessory portion of the spinal 
accessory nerve, which blends with the pneumogastric below the ganglion, and is 
then principally continued into its pharyngeal and superior laryngeal branches. 
Connecting Branches (Fig. 684).-This ganglion is connected with the hypo- 
glossal, the superior cervical ganglion of the sympathetic, and the loop between 
the first and second cervical nerves. 
The branches of the pneumogastric are- 
Meningeal. 
Auricular. 
In the jugular fossa 
Pharyngeal. 
Superior laryngeal. 
Recurrent laryngeal. 
Cervical cardiac. 
In the neck 
Thoracic cardiac. 
Anterior pulmonary. 
Posterior pulmonary. 
Oesophageal. 
In the thorax 
The Meningeal Branch (ramus meningeus).-The meningeal branch is a recurrent 
filament given off from the ganglion of the root in the jugular foramen. It passes 
In the abdomen 
Gastric. THE NERVOUS SYSTEM 
1060 
backward, and is distributed to the dura mater lining the posterior fossa of the 
base of the skull. 
The Auricular Branch or Arnold's Nerve (ramus auricularis) (Fig. 684).-The 
auricular branch or Arnold's nerve arises from the ganglion of the root, and is 
joined soon after its origin by a filament from the petrous ganglion of the glosso- 
pharyngeal; it passes outward behind the jugular vein, and enters a small canal 
on the outer wall of the jugular fossa. Traversing the substance of the tem- 
poral bone, it crosses the acpiaeductus Fallopii about two lines above its termina- 
tion at the stylo-mastoid foramen; here it gives off an ascending branch, which 
joins the facial; the continuation of the nerve reaches the surface by passing 
through the auricular fissure between the mastoid process and the external audi- 
tory meatus, and divides into two branches, one of which communicates with the 
posterior auricular nerve, while the other supplies the integument at the back 
part of the pinna and the posterior part of the external auditory meatus. 
The Pharyngeal Branch (ramus pharyngeus).-The pharyngeal branch, the prin- 
cipal motor nerve of the pharynx, arises from the upper part of the ganglion of the 
trunk of the pneumogastric. It consists principally of filaments from the accessory 
portion of the spinal accessory; it passes across the internal carotid artery to the 
upper border of the Middle constrictor of the pharynx, where it divides into 
numerous filaments which join with those from the glosso-pharyngeal, the supe- 
rior laryngeal (its external branch), and sympathetic, to form the pharyngeal plexus 
(plexus pharyngeus), from which branches are distributed to the muscles and 
mucous membrane of the pharynx and the muscles of the soft palate. From the 
pharyngeal plexus a minute filament is given off, which descends and joins the 
hypoglossal nerve as it winds around the occipital artery. 
The Superior Laryngeal Nerve (n. laryngeus superior) (Figs. 683, 6S4, and 685).- 
It is larger than the preceding, and arises from the middle of the ganglion of the 
trunk of the pneumogastric. It consists principally of filaments from the accessory 
portion of the spinal accessory. In its course it receives a branch from the supe- 
rior cervical ganglion of the sympathetic. It descends by the side of the pharynx 
behind the internal carotid artery, where it divides into two branches, the external 
and internal laryngeal. This nerve is the nerve of sensation of the larynx, and 
also supplies the crico-thyroid muscle. Exner has pointed out that the superior 
laryngeal nerve innervates to some extent the muscles supplied by the inferior 
laryngeal, and this fact explains why division of the inferior laryngeal nerve is not 
of necessity followed by complete paralysis of the muscles it supplies. 
The External Laryngeal Branch of the Superior Laryngeal (ramus externus) (Fig. 
685), the smaller, descends by the side of the larynx, beneath the Sterno-thyroid, 
to supply the Crico-thyroid muscle. It gives branches to the pharyngeal plexus 
and the Inferior constrictor, and communicates with the superior cardiac nerve, 
behind the common carotid. 
The Internal Laryngeal Branch of the Superior Laryngeal (ramus intern us) 
descends to the opening in the thyro-hyoid membrane, through which it passes 
with the superior laryngeal artery, and is distributed to the mucous membrane of 
the larynx. A small branch communicates with the recurrent laryngeal nerve. 
The branches to the mucous membrane are distributed, some in front to the epi- 
glottis, the base of the tongue, and the epiglottidean glands; while others pass 
backward, in the aryteno-epiglottidean fold, to supply the mucous membrane 
surrounding the superior orifice of the larynx, as well as the membrane which 
lines the cavity of the larynx as low down as the vocal cord. The filament which 
joins with the recurrent laryngeal descends beneath the mucous membrane on the 
inner surface of the thyroid cartilage, where the two nerves become united. 
The Inferior or Recurrent Laryngeal Branch of the Pneumogastric (n. laryngeus 
inferior) (Figs. 684 and 685).-The inferior or recurrent laryngeal branch, so 
called from its reflected course, is the motor nerve of the larvnx. It arises on THE TENTH OR PNEUMOGASTRIC NERVE 
1061 
the right side, in front of the subclavian artery; winds from before backward 
around that vessel, and ascends obliquely to the side of the trachea, behind 
the common carotid artery and behind or in front of the inferior thyroid artery. 
On the left side it arises in front of the arch of the aorta, and winds from 
before backward around the aorta at the point where the remains of the ductus 
arteriosus are connected with it, and then ascends to the side of the trachea. 
The nerve on each side ascends in the groove between the trachea and oesophagus, 
and, passing under the lower border of the Inferior constrictor muscle, enters the 
larynx behind the articulation of the inferior cornu of the thyroid cartilage with 
the cricoid, being distributed to all the muscles of the larynx except the Crico- 
thyroid. It communicates with the superior laryngeal nerve and gives off a few 
filaments to the mucous membrane of the lower part of the larynx. 
The recurrent laryngeal, as it winds around the subclavian artery and aorta, 
gives off several cardiac filaments, which unite with the cardiac branches from 
the pneumogastric and sympathetic. As it ascends in the neck it gives off oesoph- 
ageal branches, more numerous on the left than on the right side, which supply 
the mucous membrane and muscular coat of the oesophagus; tracheal branches to 
the mucous membrane and muscular fibres of the trachea; and some pharyngeal 
filaments to the Inferior constrictor of the pharynx. 
The Cervical Cardiac Branches (rami cardiaci superior es) (Fig. 684).-The cer- 
vical cardiac branches, two or three in number, arise from the pneumogastric, at 
the upper and lower part of the neck. 
The Superior Branches are small, and communicate with the cardiac branches 
of the sympathetic. They can be traced to the great or deep cardiac plexus. 
The Inferior Branches, one on each side, arise at the lower part of the neck, 
just above the first rib. On the right side this branch passes in front or by the 
side of the arteria innominata, and communicates with one of the cardiac nerves 
proceeding to the great or deep cardiac plexus. On the left side it passes in front 
of the arch of the aorta and joins the superficial cardiac plexus. 
The Thoracic Cardiac Branches (rami cardiaci inferiores) (Fig. 684).-The thoracic 
cardiac branches, on the right side, arise from the trunk of the pneumogastric 
as it lies by the side of the trachea, and from its recurrent laryngeal branch, but 
on the left side from the recurrent nerve only; passing inward, they terminate 
in the deep cardiac plexus. 
The Anterior Pulmonary Branches (Fig. 684).-The anterior pulmonary branches, 
two or three in number, and of small size, are distributed on the anterior aspect 
of the root of the lungs. They join with filaments from the sympathetic, and form 
the anterior pulmonary plexus (plexus pulmonalis anterior). 
The Posterior Pulmonary Branches (Fig. 684).-The posterior pulmonary branches, 
more numerous ami larger than the anterior, are distributed on the posterior aspect 
of the root of the lung; they are joined by filaments from the third and fourth 
(sometimes also from the first and second) thoracic ganglia of the sympathetic, 
and form the posterior pulmonary plexus (plexus pidmonalis posterior). Branches 
from both plexuses accompany the ramification of the air-tubes through the sub- 
stance of the lungs (rami bronchioles anteriores and rami bronchioles poster lores). 
The Oesophageal Branches (rami oesophagei).-The oesophageal branches are 
given off from the pneumogastric both above and below the pulmonary branches. 
The lower are more numerous and larger than the upper. They form, together 
with branches from the opposite nerve, the oesophageal plexus (plexus gulae). 
From this plexus branches are distributed to the back of the pericardium. 
The Gastric Branches (rami gastrici) (Figs. 684 and 685.-The gastric branches 
are the terminal filaments of the pneumogastric nerve. The nerve on the right 
side is distributed to the posterior surface of the stomach. The right pneumo- 
gastric sends branches to the coeliac plexus (rami coeliaci), to the splenic plexus 
(rami lienales), and to the renal plexus (rami renales). The nerve on the left 1062 
THE NERVOUS SYSTEM 
side is distributed over the anterior surface of the stomach, some filaments (rami 
hepatici) passing across the great cul-de-sac, and others along the lesser curva- 
ture. They unite with branches of the right nerve and with the sympathetic, 
some filaments passing through the lesser omentum to the hepatic plexus. 
Surgical Anatomy.-The laryngeal nerves are of considerable importance in considering 
some of the morbid conditions of the larynx. When the peripheral terminations of the superior 
laryngeal nerve are irritated by some foreign body passing over them, reflex spasm of the glottis 
is the result. When the trunk of the same nerve is pressed upon by, for instance, a goitre or 
an aneurism of the upper part of the carotid, we have a peculiar dry, brassy cough. When the 
nerve is paralyzed, we have anaesthesia of the mucous membrane of the larynx, so that foreign 
bodies can readily enter the cavity, and, in consequence of its supplying the crico-thyroid muscle, 
the vocal cords cannot be made tense, and the voice is deep and hoarse. Paralysis of the supe- 
rior laryngeal nerves may be the result of bulbar paralysis, may be a sequel to diphtheria, when 
both nerves are usually involved, or it may, though less commonly, be caused by the pressure 
of tumors or aneurisms, when the paralysis is generally unilateral. Irritation of the inferior 
laryngeal nerves produces spasm of the muscles of the larynx. When both the recurrent 
nerves are paralyzed, the vocal cords are motionless in the so-called cadaveric position-that 
is to say, in the position in which they are found in ordinary tranquil respiration-neither closed 
as in phonation, nor open as in deep inspiratory effort. When one recurrent nerve is paralyzed, 
the cord of the same side is motionless, while the opposite cord crosses the middle line to accom- 
modate itself to the affected one; hence phonation is present, but the voice is altered and weak 
in timbre. The recurrent laryngeal nerves may be paralyzed in bulbar paralysis or after diph- 
theria, when the paralysis usually affects both sides; or they may be affected by the pressure 
of aneurisms of the aorta, innominate or subclavian arteries; by mediastinal tumors; by bron- 
chocele; or by cancer of the upper part of the oesophagus, when the paralysis is often unilat- 
eral. The nerve may be accidentally divided during the operation for goitre. 
It is a well-recognized fact that disease or injury of the vagus may induce serious symptoms. 
Bruising may cause such symptoms; so may injury of the nerve by a stab, a bullet, or during 
surgical operations. Either accidental ligation or crushing with clamp forceps is particularly 
dangerous. Michaux accidentally ligated the vagus, and the patient became comatose and 
ceased to breathe, but was restored on removing the ligature. Tillmanns, while removing a 
cancer, accidentally caught and crushed a portion of the nerve in a clamp, and both pulse and 
respiration ceased. The clamp was removed, the patient was restored with difficulty, and the 
nerve was sutured. Recovery followed. It thus becomes evident that division of the vagus on 
one side is not, as was so long taught, a necessarily fatal accident; in fact, it is sometimes under- 
taken deliberately in removing tumors adherent to the nerve. Division of a nerve which has 
been long compressed is probably not so dangerous as division of a healthy nerve, as in the former 
case the opposite vagus has probably assumed some of its colleague's duties. A number of cases 
of deliberate division have been reported. Twenty-three cases are referred to in the system of 
surgery by von Bergmann and Mikulicz, and twelve of them died, but in none of the deaths was 
the removal of the vagus the apparent cause of the fatality. The editor of this American edition 
of "Gray" has seen three cases: One was operated upon by Dr. W. Joseph Hearn, one by Dr. 
Melvin Franklin, and one by the editor. All three recovered, and not one presented any 
serious disturbance, although each had hoarseness and weakness of voice. 
One would assume that after division of the pneumogastric below the superior laryngeal nerve 
and above the recurrent laryngeal nerve (the region usually attacked) that there would be 
paralysis of all the muscles of one side of the larynx, except the crico-thyroid, and wide- 
spread aberration evinced by disturbances of the heart, stomach, and lungs. As a matter of fact, 
this has not been the case. It might be and probably would be the case, were a healthy nerve 
divided; but the surgeon who deliberately divides the nerve does so during the removal of a 
tumor which has long made pressure. In most cases there is no change in the pulse or 
respiration. In some cases dysphagia and pneumonia arise, but they may be due to other causes 
than pneumogastric injury (the formidable nature and the duration of the operation-the 
ligation of vessels of large size-the age of the subject). 
Laryngeal symptoms, to a greater or less degree, are always noted. The difference in the 
degree of the palsy is explainable when we recall Exner's statement that the muscles supplied 
by the recurrent laryngeal also receive some innervation from the superior laryngeal. In fact, 
Mills points out that a portion of the recurrent laryngeal has been resected without completely 
paralyzing the muscles supposed to be supplied solely by the recurrent laryngeal. The laryngeal 
symptoms result from unilateral laryngeal paralysis, in which there is paralysis of the muscles 
which open the glottis. The voice may be lost or may be hoarse. Usually, after a time, this is, 
to a great extent, compensated for by the opposite vocal cord, although the voice may alway 
remain weak, and the patient will tire easily on talking. If both pneumogastrics were to be 
divided death would ensue. THE ELEVENTH OR SPINAL ACCESSORY NERVE 
1063 
THE ELEVENTH OR SPINAL ACCESSORY NERVE (N. ACCESSORIUS) 
(Figs. 683, 684, 685). 
The eleventh or spinal accessory nerve consists of two parts: one the accessory 
part to the vagus, and the other the spinal portion. 
The Bulbar or Accessory Part of the Spinal Accessory Nerve. 
The bulbar or accessory part is the smaller of the two. It is accessory to the 
vagus. Its superficial origin (Fig. 683) is by four or five delicate filaments from 
the side of the medulla, below the roots of the vagus. Its deep origin (Fig. 613) 
may be traced to a nucleus of gray matter at the back of the medulla, dorso-lateral 
to the hypo-glossal nucleus, and extending as far down as the intermedio-lateral 
tract of the spinal cord. It passes outward to the jugular foramen, where it inter- 
changes fibres with the spinal portion or becomes united to it for a short distance; 
it is also connected, in the foramen, with the upper ganglion of the vagus by one 
or two filaments. It then passes through the foramen (Fig. 685), and becoming 
again separated from the spinal portion it is continued over the surface of the 
ganglion of the trunk of the vagus, being adherent to its surface, and is distributed 
principally to the pharyngeal and superior laryngeal branches of the pneumogastric 
(Fig. 684). Through the pharyngeal branch it probably supplies the muscles of 
the soft palate. Some few filaments from it are continued into the trunk of the 
vagus below the ganglion, to be distributed with the recurrent laryngeal nerve, 
and probably also with the cardiac nerves. 
The Spinal Portion of the Spinal Accessory Nerve. 
The spinal portion is firm in texture. Its superficial origin (Fig. 683) is by 
several filaments or rootlets from the lateral tract of the cord, as low down as 
the sixth cervical nerve. Its deep origin (Fig. 613) may be traced to the inter- 
medio-lateral tract of the gray matter of the cord. The rootlets of origin join and 
form a trunk which ascends in the subdural space between the ligamentum den- 
ticulatum and the posterior roots of the spinal nerves, enters the skull through the 
foramen magnum, and is then directed outward to the jugular foramen, through 
which it passes, lying in the same sheath as the pneumogastric, but separated from 
it by a fold of the arachnoid. In the jugular foramen it receives one or two 
filaments from the accessory portion. At its exit from the jugular foramen it 
passes into the neck and becomes the external branch {ramus externus) (Figs. 634, 
684, and 685). It passes backward, either in front of or behind the internal 
jugular vein, and descends obliquely behind the Digastric and Stylo-hyoid muscles 
to the upper part of the Sterno-mastoid muscle. It pierces that muscle, and 
passes obliquely across the posterior triangle, to terminate in the deep surface of 
the Trapezius muscle. This nerve gives several branches to the Sterno-mastoid 
muscle during its passage through it, and joins in its substance with branches 
from the second cervical, which supply the muscle. In the posterior triangle it 
joins with the second and third cervical nerves, while beneath the Trapezius it 
forms a sort of plexus with the third and fourth cervical nerves, and from this 
plexus fibres are distributed to the muscle. 
Surgical Anatomy. -Division of the external branch of the spinal accessory nerve causes 
paralysis of the Sterno-cleido-mastoid and Trapezius muscles; not absolute paralysis, for these 
muscles also receive nerves from the cervical plexus. In cases of spasmodic torticollis in which 
all palliative treatment has failed, division or excision of a portion of the external branch of the 
spinal accessory nerve has been suggested by Keen. This may be done either along the anterior or 
posterior border of the Sterno-mastoid muscle. The former operation is performed by making 1064 
THE NERVOUS SYSTEM 
an incision from the apex of the mastoid process, three inches in length, along the anterior border 
of the Sterno*mastoid muscle. The anterior border of the muscle is defined and pulled back- 
ward, so as to stretch the nerve, which is then to be sought for beneath the Digastric muscle, 
about two inches below the apex of the mastoid process. The other operation consists in 
making an incision along the posterior border of the muscle, so that the centre of the incision 
corresponds to the middle of this border of the muscle. The superficial structures having been 
divided and the border of the muscle defined, the nerve is to be sought for as it emerges from 
the muscle to cross the occipital triangle. When found, it is to be traced upward through the 
muscle, and a portion of it is excised above the point where it gives off its branches to the Sterno- 
mastoid. In this operation one of the descending branches of the superficial cervical plexus is 
liable to be mistaken for the nerve. 
THE TWELFTH OR HYPOGLOSSAL NERVE (N. HYPOGLOSSUS) 
(Figs. 686, 687). 
The twelfth or hypoglossal nerve is the motor nerve of the tongue. Its super- 
ficial origin is by several filaments, from ten to fifteen in number, from the groove 
To Dura-mater 
To Symphysis 
To Ganglion on Trunk of Vagus 
c. I 
Hypoglossal Nerve 
Branch from first Cervical 
to Hypoglossal 
>c.n 
To Muscles 
of Tongue 
To Genio-hyoid 
To Lingual Nerve 
Com. Hypog\ 
To Thyro-hyoid 
To Anterior Belly of Omo-hyoid 
To Sterno-hyoid 
To Posterior Belly of Omo-hyoid 
To Sterno-thyroid 
Fig. 686.-Plan of the hypoglossal nerve. 
between the pyramidal and olivary bodies of the medulla, in a continuous line 
with the anterior roots of the spinal nerves. Its deep origin can be traced to a 
nucleus of gray matter (trigonum hypoglossi) on the floor of the fourth ventricle 
(Fig. 613). 
The filaments of this nerve are collected into two bundles, which perforate the 
dura mater separately, opposite the anterior condyloid foramen, and unite together 
after their passage through it. In those cases in which the anterior condyloid THE TWELFTH Oli HYPOGLOSSAL NERVE 
1065 
foramen in the occipital bone is double, these two portions of the nerve are sepa- 
rated by the small piece of bone which divides the foramen. The nerve descends 
almost vertically to a point corresponding with the angle of the jaw. It is at first 
deeply seated beneath the internal carotid artery and internal jugular vein, and is 
intimately connected with the pneumogastric nerve (Fig. 687); it then passes for- 
ward between the vein and artery, and lower down in the neck becomes superficial 
below the Digastric muscle. The nerve then loops around the occipital artery, 
and crosses the external carotid and its lingual branch below the tendon of the 
Digastric muscle. It passes beneath the tendon of the Digastric, the Stylo-hyoid, 
and the Mylo-hyoid muscles, lying between the last-named muscle and the Hyo- 
Hypo-glossal nerve. 
Pneumogastric nerve. 
Glosso-pharyngeal nerve. 
Fig. 687.-Hypoglossal nerve, cervical plexus, and their branches. 
glossus (Fig. 687), and communicates at the anterior border of the Hyo-glossus 
with the lingual or gustatory nerve (Fig. 686); it is then continued forward in the 
fibres of the Genio-hyoglossus muscle as far as the tip of the tongue, distributing 
branches to its muscular substance. 
Branches of Communication (Fig. 686).-The branches of communication are 
-with the 
Pneuinogastric. 
Sympathetic. 
First and Second Cervical Nerves 
Lingual (gustatory). 
The first mentioned takes place close to the exit of the nerve from the skull, 
numerous filaments passing between the hypoglossal and the ganglion of the trunk 1066 
THE NERVOUS SYSTEM 
of the pneumogastric through the mass of connective tissue which here unites the 
two nerves. It also communicates with the pharyngeal plexus by a minute filament 
as it winds around the occipital artery. 
The communication with the sympathetic takes place opposite the atlas vertebra 
by branches derived from the superior cervical ganglion, and in the same situa- 
tion the nerve is joined by filaments derived from the loop connecting the first 
two cervical nerves. 
The communication with the lingual (gustatory) takes place near the anterior 
border of the Hyo-glossus muscle by numerous filaments which ascend upon it. 
Branches of Distribution (Fig. 686).-The branches of distribution are-the 
Meningeal. 
Descendens hypoglossi. 
Thyro-hyoid. 
Muscular. 
Meningeal Branches (Fig. 686).-As the hypoglossal nerve passes through the 
anterior condyloid foramen it gives off, according to Luschka, several filaments to 
the dura mater in the posterior fossa of the base of the skull; these filaments are 
probably derived from a branch which passes from the first cervical nerve to the 
hypoglossal nerve. 
The Descendens Hypoglossi (ramus descendens) (Figs. 686 and 687).-The 
descendens hypoglossi, long called the descendens noni, is a long slender branch, 
which quits the hypo-glossal where it turns around the occipital artery. It con- 
sists mainly of fibres which pass to the hypoglossal from the first and second 
cervical nerves in the above-mentioned communication. It descends in front of 
or within the sheath of the common carotid artery, giving off a branch to the 
anterior belly of the Omo-hyoid, and then joins the communicating branches 
from the second and third cervical nerves, just below the middle of the neck, to 
form a loop, the ansa hypo-glossi. From the convexity of this loop branches pass 
to supply the Sterno-hyoid, Sterno-thyroid, and the posterior belly of the Omo- 
hyoid. According to Arnold, another filament descends in front of the vessels into 
the chest, and joins the cardiac and phrenic nerves. 
The Thyro-hyoid Branch (ramus thyreohyoideus) (Fig. 686).-The thyro-hyoid 
is a small branch arising from the hypoglossal near the posterior border of the 
Hyo-glossus; it passes obliquely across the great cornu of the hyoid bone and 
supplies the Thyro-hyoid muscle. 
The Muscular Branches (Fig. 686).-The muscular branches are distributed to 
the Stylo-glossus, Hyo-glossus, Genio-hyoid, and Genio-hyo-glossus muscles. At 
the under surface of the tongue numerous slender branches (rami linguales) pass 
upward into the substance of the organ to supply its intrinsic muscles. 
Surgical Anatomy.-A wound in the submaxillary region may injure the hypoglossal nerve 
and result in motor paralysis of the corresponding half of the tongue. The hypoglossal nerve is 
an important guide in the operation of ligation of the lingual artery (see page 604). It runs forward 
on the Hyo-glossus muscle just above the great cornu of the hyoid bone, and forms the upper 
boundary of the triangular space in which the artery is to be sought for by cutting through the 
fibres of the Hyo-glossus muscle. 
THE SYMPATHETIC NERVE (SYMPATHICUS) (Fig. 688). 
The sympathetic nervous system consists of (1) a series of ganglia {ganglia trunci 
sympathici) connected together by a great ganglionic cord, the gangliated cord 
{truncus sympathicus), extending from the base of the skull to the coccyx, one 
gangliated cord on each side of the middle line of the body, partly in front and 
partly on each side of the vertebral column; (2) of three great gangliated plexuses 
{plexus sympathici) or aggregations of nerves and ganglia, situated in front of THE SYMPATHETIC NERVE 
1067 
the spine in the thoracic, abdominal, 
and pelvic cavities respectively; (3) of 
smaller or terminal ganglia, situated in 
relation with the abdominal viscera ; 
and (4) of numerous nerve-fibres. These 
latter are of two kinds : communicating, 
by which the ganglia communicate with 
each other and with the cerebro-spin al 
nerves ; and distributory, supplying the 
internal viscera and the coats of the 
blood-vessels. 
Each gangliated cord may be traced 
upward from the base of the skull 
into the cranial cavity by an ascending 
branch, which passes through the caro- 
tid canal, forms a plexus on the internal 
carotid artery and in the cavernous 
sinus (Fig. 692), and communicates 
with certain cranial nerves (p. 1073). 
According to some anatomists, the two 
cords are joined, at their cephalic ex- 
tremities, by these ascending branches 
communicating in a small ganglion, 
the ganglion of Ribes, situated upon the 
anterior communicating artery. Upon 
the gangliated cord are ganglia dis- 
tinguished as cervical, dorsal, lumbar, 
and sacral, and except in the neck they 
Fig. 688.-The sympathetic nerve, reduced in size 
from Byron Robinson's life-size drawing of a dissection 
made by himself. 
I.-VIII., cervical nerves; 2 a, 2 b, 1 c, 1 d, brachial 
plexus; 1, spinal accessory nerve (XI. nerve); 2, hypo- 
glossal nerve (XII. nerve); 3, vagus nerve (X. nerve); 
4, descendens nomi nerve; 5, laryngeal nerve; 6, supe- 
rior cervical ganglion; 7, middle cervical ganglion; 8, 9, 
inferior cervical ganglion; 10, two superior cardiac 
nerves; 11, two middle cardiac nerves; 12, two ganglia 
on 10 and 11; 13, branch connecting the inferior cervi- 
cal ganglion to phrenic nerve; 14, I. dorsal nerve; 15, 
left subclavian artery; 16, carotid artery; 17, right sub- 
clavian artery; 18, Wrisberg's ganglion; 19, a, sym- 
pathetic branches to the heart; 19, three inferior car- 
diac nerves. The phrenic nerve in this subject arose 
from the III., IV., and V. cervical nerves; 20 to 39, 
lateral chain of sympathetic ganglia; 40, left recurrent 
laryngeal nerve; 41, superior splanchnic nerve; 42, mid- 
dle splanchnic nerve; 43, inferior splanchnic nerve; 44, 
45, aortic branches from the lateral chain of ganglia; 45 
to 56, intercostal nerve; 57, diaphragmatic ganglion; 
58, right vagus nerve; 59, left vagus nerve; 60, nerve 
joining the vagi; 61, coeliac axis; 62, phrenic artery sur- 
rounded by the phrenic plexus, which is connected 
with the phrenic ganglion (57); 63. 64, abdominal 
brain (ganglion coeliacum); 65, renal ganglion, I. L., 
II. L., III. L., IV. L., V. L., lumbar nerves; 66, right 
superior splanchnic nerve; 67, seven nerves passing 
to the adrenal; 68, rich meshwork of nerves surround- 
ing left renal artery; 69, right renal ganglion; 70, 71, 
ovarian ganglion; 72, aortic plexus; 73, inferior mesen- 
teric ganglion; 74, hypogastric plexus; 75, 76, 77, pel- 
vic brain (ceryico-vaginal ganglion). At 75 branches 
from the pelvis brain are emitted to rectum, vagina, 
and bladder. At 76 the branches from the II., III., 
and IV. sacral nerves join the pelvic brain. At 77 the 
uterine nerves are emitted to supply the uterus; 78. 
oviducal nerves; 79, uterine nerves; 80, bladder; 81 , 
vagina; 82, 83, rectum; I. S., U. S., III. S., IV. S., sacral 
nerves; 84, arteria uterina ovarica. The right lumbar 
lateral chain is not numbered; 85, nerves to levator ani; 
II. and Hy., ileo-hypogastric; H., ileo-inguinal; Ec., 
external cutaneous; A c., anterior crural; Obt., Obtura- 
tor; G. C., genito-crural; G. S., great sciatic. 1068 
THE NE11VOUS SYSTEM 
correspond pretty nearly in number to the vertebrae against which they lie. 
They may be thus arranged: 
Cervical portion .... 3 pairs of ganglia. 
Dorsal " . . . .12 
Lumbar " . . .4 
Sacral " . . . 4 or 5 
In the neck they are situated in front of the transverse processes of the verte- 
brae; in the dorsal region, in front of the heads of the ribs; in the lumbar region, 
on the sides of the bodies of the vertebrae; and in the sacral region, in front of the 
sacrum. As the two cords pass into the pelvis they converge and unite together 
in a single ganglion, the coccygeal ganglion or ganglion impar (ganglion coccygeum 
impar) placed in front of the coccyx. Each ganglion may be regarded as a dis- 
tinct centre, and, in addition to its branches of distribution, possesses also branches 
of communication which communicate with other ganglia and with the cerebro- 
spinal nerves. 
The branches of communication between the ganglia (Figs. 689 and 690) are 
composed of gray nerve-fibres (gray rami communicantes) and white nerve-fibres 
(white rami communicantes), the latter being continuous with those fibres of the 
spinal nerves which pass to the ganglia. 
The three great gangliated plexuses (collateral ganglia) are situated in front of 
the spine in the thoracic, abdominal, and pelvic regions, and are named, respec- 
tively, the cardiac, the solar or epigastric, and the hypogastric plexus. They consist 
of collections of nerves and ganglia, the nerves being derived from the gangliated 
cords and from the cerebro-spinal nerves. They distribute branches to the 
viscera. 
Smaller or Terminal ganglia are also found lying amidst the nerves, some of them 
of microscopic size, in certain viscera-as, for instance, in the heart, the stomach, 
and the uterus. They serve as additional centres for the origin of nerve-fibres. 
There are numerous special ganglia connected with the cranial nerves. 
These ganglia have been described in a previous section (see ophthalmic 
ganglion, otic ganglion, spheno-palatine ganglion, and submaxillary ganglion). 
The branches of distribution derived from the gangliated cords, from the p re- 
vertebral plexuses, and also from the smaller ganglia, are principally destined 
for the blood-vessels and thoracic and abdominal viscera, supplying the involun- 
tary muscular fibre of the coats of the vessels and the hollow viscera, and the 
secreting cells, as well as the muscular coats of the vessels in the glandular viscera. 
Structure of the Sympathetic System.-The sympathetic system is not, as 
was so long taught, an independent system. It receives fibres from the cerebro- 
spinal system and arranges them for distribution to the splanchnic blood-vessels 
and the viscera. It receives fibres from the viscera and transmits them to the 
cerebro-spinal system, and it transmits fibres by way of the spinal nerves to 
unstriped muscles, to vessels, and to glands. It is simply an arrangement of spinal 
nerves to permit of the re-arrangement and transmission of impulses. In order 
to effect this, the spinal nerves are connected with a series of ganglia, which possess 
a certain power of government or automatic action. In the sympathetic system 
non-medullated fibres predominate. The individual nerve-fibres are smaller in 
diameter than those of the cerebro-spinal system, and the fibres are interrupted 
by nerve-cells contained in a ganglia chain, known as the gangliated cord, and are 
also sometimes interrupted in gangliated plexuses and in terminal ganglia. The 
sympathetic nerves have a notable disposition to form plexuses. It is important to 
note that not all of the visceral branches of the spinal nerves join the gangliated 
cord-for instance, the visceral branches of the third and fourth sacral do not. 
The majority, but not all, of the sympathetic fibres are non-medullated (fibres of THE SYMPATHETIC NERVE 
1069 
Remak}, but in the adult true non-medullated fibres are found only in the sym- 
pathetic system. These fibres are of smaller diameter than spinal nerve-fibres, and 
are prolongations of axones of sympathetic ganglia cells. Each fibre is surrounded 
by connective-tissue structure which resembles the neurilemma, which contains 
numerous nuclei, and which is a prolongation of the capsule of a sympathetic cell 
capsule. 
A sympathetic nerve consists of numerous non-medullated and some medullated 
fibres. The connective tissue which separates the nerve-bundles carries blood- 
vessels and nervi nervorum, but no lymph vessels. 
The sympathetic ganglia contain multipolar cells which are smaller than those 
of the spinal ganglia. Each cell contains two nuclei, and is surrounded by a deli- 
cate capsule of connective tissue. The cell gives off one axone and several short 
-POSTERIOR ROOT 
-SPINAL GANGLION 
POSTERIOR PRIMARY 
DIVISION 
.ANTERIOR ROOT 
-WHITE RAMUS 
SPLANCHNIC EFFERENT FIBRES 
-SYMPATHETIC GANGLION 
ANTERIOR PRIMARY 
DIVISION 
SPLANCHNIC AFFERENT FIBRES 
Fig. 689.-The white ramus communicans (schematic). (After Cunningham.) 
dendrites. The axone is non-medullated when it begins and may remain so or 
may become mednllated. Fibres which take origin from sympathetic axones, 
the commissural fibre, may pass to an adjacent ganglion cell, may pass toward the 
centre central fibre or gray ramus communicans, or may pass toward the periphery, 
peripheral fibre, and reach certain glands, or to unstriped muscle of blood-vessels, 
intestines, iris, etc. The fibres passing to glands are called secretory fibres. 
The dendrites of a sympathetic ganglion cell form arborizations about other 
ganglion cells. The sympathetic ganglia contain fibres, as well as cells. Some of 
the fibres are medullated and some are non-medullated, the latter taking origin 
from the sympathetic ganglion cells, the former being motor and sensory cere- 
brospinal fibres which have reached the sympathetic by the rami communi- 
cantes.1 
1 Histology and Microscopic Anatomy, by Szymonowicz. Translated and edited by John Bruce MacCallum. 1070 
THE NERVOUS SYSTEM 
The medullated fibres, the white rami communicantes or the visceral branches of 
the spinal nerves (Figs. 689 and 69(f) originate from the anterior divisions of certain 
spinal nerves. Two groups of them can be recognized, one group coming from 
the nerves from the first or second dorsal to the second or third lumbar nerves; 
another group from the second or third lumbar to the third or fourth sacral. The 
commissural 
FIBRE 
CENTRAL 
FIBRE 
GANGLION CELLS 
AND AXONS 
SPLANCHNIC 
EFFERENT 
SPLANCHNIC 
AFFERENT 
GRAY 
RAMUS 
PERIPHERAL 
l H8RE 
WHITE 
RAMUS 
COLLATERAL 
GANGLION 
GRAY RAMUS 
WHITE RAMUS 
Fig. 690.-Scheme of the constitution and connections of the gangliated cord of the sympathetic. The 
gangliated cord is indicated on the right with the arrangement of the fibres arising from the ganglion cells. _ On 
the left the roots and trunks of spinal nerves are shown, with the arrangement of the white ramus communicans 
above and the gray ramus below. (Cunningham.) 
visceral branches of the third and fourth sacral do not join the gangliated cord; the 
other visceral branches do join it. The fibres of the visceral branches of the spinal 
nerves are derived from both the anterior and the posterior nerve-roots, but more 
largely from the anterior than from the posterior. The visceral fibres of the anterior 
roots are axones of nerve-cells of the spinal cord, and by way of the white rami enter 
into the sympathetic ganglia. Some of them end and form networks about the THE CERVICAL PORTION OF THE GANGLIATED CORD 
1071 
ganglia cells. Others pass up or down and end in an adjacent ganglion. Others 
pass through a ganglion of the gangliated cord and end in a peripheral ganglion 
with non-medullated fibres, which take origin from ganglia of the gangliated cord. 
The fibres of the white ramus which pass through the ganglion and go to the 
periphery are known as the splanchnic efferent fibres, and constitute the secretory 
fibres of the splanchnic glands and the motor fibres of the muscular tissue of 
splanchnic blood-vessels and viscera. The visceral fibres of the posterior nerve- 
roots aid in the formation of the white rami and arise as axones of nerve-cells in 
the spinal ganglia on the posterior roots, pass through the ganglia of the sympa- 
thetic cord, but do not terminate in them, and leave the ganglion directly to pass 
through a peripheral ganglion to be distributed to the periphery or ascend or 
descend to an adjacent ganglion and pass through this to a collateral ganglion, and 
from that to the periphery. They constitute the splanchnic afferent fibres, the 
sensory fibres of the viscera. 
The non-medullated fibres take origin from the cells of the sympathetic gan- 
glia and are axones of these cells. Some help to form the commissure, which 
joins a ganglion to adjacent ganglia and end as networks about the cells of an 
adjacent ganglion. Others run to the periphery and help to form the splanchnic 
efferent branches. Some pass from the ganglia to the spinal nerve-roots and to 
the anterior and posterior divisions of the nerves. The latter are the gray rami 
communicantes (Fig. 690), largely composed of non-medullated but containing 
some medullated fibres. They give branches to the somatic part of the nerves 
and not the visceral, and furnish secretory fibres and fibres to unstriated muscle 
and minute branches to the membranes which enwrap the nerve-roots. The 
commissures of the gangliated cord are composed of white and gray fibres. 
The former consist of both splanchnic efferent and splanchnic afferent fibres. The 
latter are axones from sympathetic ganglion cells, and some of these are truly com- 
missural, but others pass up or down the cord and through a ganglion and become 
branches which go to the periphery. 
From the above it becomes evident that the peripheral branches of the sym- 
pathetic contain white fibres, which are composed of splanchnic efferent and 
splanchnic afferent branches and also contain splanchnic efferent gray fibres. 
Fig. 690, from Cunningham's Text-book of Anatomy, exhibits the constitution 
and connections of the gangliated cord of the sympathetic. 
THE GANGLIATED CORD (TRUNCUS SYMPATHICUS). 
The Cervical Portion (Pars Cervicalis) of the Gangliated Cord. 
The cervical portion of the gangliated cord is to be regarded as a prolongation 
upward of the primitive sympathetic along the great vessels of the neck (Prof. 
Cunningham). It is not connected to the cervical spinal nerves by white rami 
communicantes. It obtains its spinal fibres from the upper dorsal nerves. These 
fibres ascend in the commissure of the gangliated cord and join the cells of the 
cervical ganglia. From the cervical ganglia come fibres to the unstriped muscle 
(veins and arteries of the head, neck, and limbs, and to the skin of the head and 
neck, secretory fibres to the salivary glands and fibres to the heart). The fibres 
to the vessels are called vasomotor nerves, and the fibres to the heart are called 
cardio-motor nerves. In the neck the gangliated cord is situated behind the carotid 
vessels and upon the muscles in front of the vertebrae, and runs from the root 
of the neck to the base of the skull, being continuous below with the thoracic 
gangliated cord and ending above in the carotid plexus. There are usually three 
ganglia on each side, each of which is distinguished, according to its position, as 
the superior, middle and inferior cervical ganglion. 1072 
THE NERVOUS SYSTEM 
The Superior Cervical Ganglion {ganglion cervicale superius) (Figs. 691, 692, 
and 693).-The superior cervical ganglion, the largest of the three, is about three- 
Carotid plexus., 
Superior cervical ganglion. 
Pharyngeal branches. 
Middle cervical ganglion. 
Inferior cervical ganglion. 
Cardiac branches. 
Deep cardiac plexus. 
•Superficial cardiac plexus. 
Dorsal ganglia. 
Solar plexus. 
Aortic plexus. 
Lumbar ganglia.- 
Hypogastric plexus. 
Sacral ganglia. 
Ganglion impar 
Fig. 691.-The sympathetic nerve. THE CERVICAL PORTION OE THE GANGLIATED CORD 
1073 
quarters of an inch in length. It is placed opposite the second and third cervical 
vertebrae. It is of a reddish-gray color, is usually fusiform in shape, is sometimes 
broad and flattened, and is occasionally constricted at intervals, so as to give rise to 
the opinion that it consists of the coalescence of several smaller ganglia; and it is 
usually believed that it is formed by the coalescence of the four ganglia correspond- 
ing to the four upper cervical nerves. It is in relation, in front, with the sheath 
of the internal carotid artery and internal jugular vein; behind, it lies on the 
Rectus capitis anticus major muscle. It is connected to the middle cervical gan- 
glion by the commissure of the gangliated cord. 
Branches (Fig. 693).-The branches of the superior cervical ganglion are central 
and peripheral. 
Central or Communicating Branches.-1. Gray rami communicantes arise in the 
ganglion and pass to the first,second,third,and fourth cervical nerves. 2. Branches 
are given off to certain cranial nerves in the neck (Figs. 692 and 693). What is 
known as the jugular nerve (n. jugularis) (Fig. 693) passes to the ganglion on the 
trunk of the vagus, a branch from the ganglion passes to the ganglia on the root of 
the pneumogastric (Fig. 693) and to the petrosal ganglion of the glosso-pharyngeal 
(Fig. 693), and a branch goes to the hypoglossal (Fig. 693). 
Peripheral Branches.-These branches may be divided into superior, internal 
and anterior. 
The Superior Branch of the Superior Cervical Ganglion or the Internal Carotid 
Branch (n. caroticus internus) (Fig. 692) appears to be a direct prolongation of the 
ganglion. It is soft in texture and of a reddish color. It ascends by the side of 
the internal carotid artery, and, entering the carotid canal in the temporal bone, 
divides into two branches, which lie, one on the outer, and the other on the inner, 
side of that vessel. 
The outer branch, the larger of the two, distributes filaments to the internal 
carotid artery and forms the internal carotid plexus. 
The inner branch also distributes filaments to the internal carotid, and, con- 
tinuing onward, forms the cavernous plexus. 
The Internal Carotid Plexus (plexus caroticus interims) (Figs. 691, 692, 
and 693).-The carotid plexus is situated on the outer side of the internal carotid 
artery. Filaments from this plexus occasionally form a small gangliform swelling 
on the under surface of the artery, which is called the carotid ganglion. The internal 
carotid plexus communicates with the Gasserian ganglion, with the sixth nerve, 
and the spheno-palatine ganglion, and distributes filaments to the wall of the 
carotid artery and to the dura mater (Valentin), while in the carotid canal it 
communicates with Jacobson's nerve, which is the tympanic branch of the glosso- 
pharyngeal. 
The communicating branches with the sixth nerve (Fig. 693) consist of one or 
two filaments which join that nerve as it lies upon the outer side of the internal 
carotid. Other filaments are also connected with the Gasserian ganglion. The 
communication with the spheno-palatine ganglion is effected by a branch, the 
large deep petrosal nerve (Fig. 677), which is given off from the plexus on 
the outer side of the artery, and which passes through the cartilage filling up the 
foramen lacerum medium, and joins the large superficial petrosal from the facial 
to form the Vidian nerve (Figs. 670, 672, and 677). The Vidian nerve then pro- 
ceeds along the pterygoid or Vidian canal to the spheno-palatine ganglion. The 
communication with Jacobson's nerve is effected by two branches, one of which 
is called the deep petrosal nerve, and the other the carotico-tympanic nerve; the 
latter may consist of two or three delicate filaments. 
The Cavernous Plexus (plexus cavernosus) (Figs. 692and 693).-The cavern- 
ous plexus is situated below and internal to that part of the internal carotid which is 
placed by the side of the sella turcica in the cavernous sinus, and is formed chiefly THE NERVOUS SYSTEM 
1074 
by the internal division of the ascending branch from the superior cervical ganglion. 
It communicates with the third, the fourth, the ophthalmic division of the fifth, 
and the sixth nerves, and with the ophthalmic ganglion, and distributes filaments 
to the wall of the internal carotid and to the pituitary body. The branch of com- 
munication with the third nerve (Fig. 693) joins it at its point of division; the 
branch to the fourth nerve (Fig. 693) joins it as it lies on the outer wall of the 
cavernous sinus; other filaments are connected with the under surface of the trunk 
of the ophthalmic nerve; and a second filament of communication joins the sixth 
nerve (Fig. 693). 
The filament of connection with the ophthalmic ganglion (Figs. 666 and 693) 
arises from the anterior part of the cavernous plexus; it accompanies the nasal 
nerve or continues forward as a separate branch. 
EXTERNAL 
RECTUS 
MUSCLE 
CILIARY 
NERVES 
MOTOR ROOT OF 
OPHTHALMIC GANGLION 
UPPER BRANCH 
OF THIRD 
OPHTHALMIC. 
GANGLION* 
' LOWER BRANCH 
'OF THIRD 
SENSORY ROOT 
OF OPHTHALMIC' 
GANGLION 
SYMPATHETIC ROOT OF 
OPHTHALMIC GANGLION 
THIRD NERVE 
NASAL* 
OPHTHALMIC 
ARTERY 
PITUITARY 
BODY 
GASSERIAN 
GANGLION 
;turned forward) 
OPHTHALMIC 
CAVERNOUS 
PLEXUS 
GREAT DEEP 
PETROSAL 
-SIXTH NERVE 
TEMPORO- 
MAXILLARY 
ARTICULATION 
COMMUNICATING 
BRANCH TO SIXTH 
INTERNAL 
CAROTID PLEXUS 
SMALL DEEP 
PETROSAL 
INTERNAL 
CAROTID BRANCH 
OF SUPERIOR 
CERVICAL GANGLION 
IN FERIOR 
CO ROTI COTY M PAN IC 
I NTERNAL 
CAROTID 
ARTERY 
SUPERIOR 
CERVICAL 
GANGLION 
Fig. 692.-The cephalic portion of the sympathetic nervous system, seen obliquely from above and behind. 
(Toldt.) 
Terminal Branches of the Carotid and Cavernous Plexuses.-The terminal 
filaments from the carotid and cavernous plexuses are prolonged along the internal 
carotid, forming plexuses which entwine around the cerebral and ophthalmic 
arteries; along the former vessels they may be traced on to the pia mater; along 
the latter, into the orbit, where they accompany each of the subdivisions of the 
vessel, a separate plexus passing, with the arteria centralis retinae, into the interior 
of the eyeball. The filaments prolonged on to the anterior communicating artery 
form a small ganglion, the ganglion of Ribes,1 which serves, as mentioned above, 
to connect the sympathetic nerves of the right and left sides. 
The so-called Inferior or Descending Branch of the Superior Cervical Ganglion 
communicates with the middle cervical ganglion. It is the commissure of the 
gangliated cord. 
1 The existence of this ganglion is doubted by some observers.-Ed. of 15th English edition. THE CERVICAL PORTION OE THE GANGLIATED CORD 
1075 
Accompanying branches oj internal 
carotid artery. 
To tympanic branch 
of glosso-pharyngeal. 
To sixth nerve. 
To ophthalmic ganglion. 
-To fifth nerve. 
■ To fourth nerve. 
To third nerve. 
Vidian nerve to 
•spheno-pdlatine gangl. 
To ganglion of root 
of pneumogastric. 
To petrosal ganglion 
of glosso pharyngeal. 
Large superficial petrosal from facial nerve. 
From 1st cervical nerve.- 
To ganglion of trunk of pneumogastric. 
To hypoglossal. 
From 2d cervical nerve, i 
Accompanying branches of 
external carotid artery. 
From 3d cervical nerve, s 
From l.th cervical nerve.-. 
Uniting with branches of pneumogas- 
.tric and glosso-pharyngeal, to form 
the pharyngeal plexus. 
From 5th cervical nerve.: 
From 6th cervical nerve. 
Inferior thyroid branches surrounding artery. 
Plexus sur- 
rounding vert- 
ebral artery. 
From 7th 
cervical nerve. 
From 8th cerv- 
ical nerve. 
Plexus surround- 
ing subclavian art- 
ery and its 
branches. 
To re- 
current 
laryng- 
eal. 
From 1st 
dorsal nerve. 
From id 
dorsal nerve.t 
Cardiac branches from pneumo- 
gastric and recurrent laryngeal 
nerves. 
From. 3d 
dorsal 
nerve. 
X 
.Ganglion of Wrisberg. 
To left an- 
terior pul- 
monary 
nerves. 
From kth 
dorsal 
nerve. 
To aorta, 
s vertebrae, 
oesophagus, 
and 
posterior 
pulmonary 
plexus. 
Cardiac 
plexus. 
To right 
anterior 
pulmonary 
plexus. 
From 5th 
dorsal 
nerve. 
From 6th 
dorsal 
nerve. 
Anterior or right 
coronary plexus. 
From 7th 
dorsal 
nerve. 
Fig. 693.-Plan of the cervical portion of the sympathetic. (After Flower.) 1076 
THE NERVOUS SYSTEM 
The Internal Branches of the Superior Cervical Ganglion are three in number-the 
pharyngeal, laryngeal and superior cardiac nerve. 
The pharyngeal branches (rami pharyngei) (Figs. 691 and 693) pass inward to the 
side of the pharynx, where they join with branches from the glosso-pharyngeal, 
pneumogastric, and external laryngeal nerves to form the pharyngeal plexus 
(plexus pharyngeus). 
The laryngeal branches unite with the superior laryngeal nerve and its branches. 
The superior cardiac nerve or the nervus superficialis cordis (n. cardiacus supe- 
rior) (Figs. 691 and 693) arises by two or more branches from the superior cervical 
ganglion, and occasionally receives a filament from the cord of communication 
between the first and second cervical ganglia. It runs down the neck behind the 
common carotid artery, lying upon the Longus colli muscle, and crosses in front of 
the inferior thyroid artery and recurrent laryngeal nerve. The right superior cardiac 
nerve, at the root of the neck, passes either in front of or behind the subclavian 
artery, and along the arteria innominata, to the back part of the arch of the aorta, 
where it joins the deep cardiac plexus. This nerve, in its course, is connected with 
other branches of the sympathetic; about the middle of the neck it receives fila- 
ments from the external laryngeal nerve; lower down it obtains one or two twigs 
from the pneumogastric; and as it enters the thorax it is joined by a filament 
from the recurrent laryngeal. Filaments from thig nerve communicate with the 
thyroid branches from the middle cervical ganglion. The left superior cardiac 
nerve, in the chest, runs by the side of the left common carotid artery and in 
front of the arch of the aorta to the superficial cardiac plexus, but occasionally it 
passes behind the aorta and terminates in the deep cardiac plexus. 
'Fhe Anterior Branches of the Superior Cervical Ganglion (nn. carotid extcrni) 
(Fig. 693) ramify upon the external carotid artery and its branches, forming around 
each a delicate plexus, on the nerves composing which small ganglia are occasion- 
ally found. The plexuses accompanying some of these arteries have important 
communications with other nerves. That surrounding the external carotid artery 
(^plexus caroticus externus) is connected with the branch of the facial nerve to the 
Stylo-hyoid muscle ; that surrounding the 
facial artery communicates with the sub- 
maxillary ganglion by one or two filaments; 
and that accompanying the middle menin- 
geal artery sends offsets which pass to the 
otic ganglion and to the geniculate gan- 
glion of the facial nerve and constitute the 
external superficial petrosal nerve (Fig. 677). 
The Middle Cervical or Thyroid Gan- 
glion (ganglion cervical medium) (Figs. 391 
and 693).-The middle cervical or thyroid 
ganglion is the smallest of the three cervical 
ganglia, and is occasionally altogether want- 
ing. It varies somewhat in position, but in 
most individuals is placed opposite the sixth cervical vertebra, usually upon, or 
close to, the inferior thyroid artery; hence the name, thyroid ganglion, assigned to 
it by Haller. It is probably formed by the coalescence of two ganglia corre- 
sponding to the fifth and sixth cervical nerves. 
It communicates above with the superior cervical ganglion and below with 
the inferior cervical ganglion by means of the commissure of the gangliated cord. 
The Central Communicating Branches (Fig. 693).-The central communicating 
branches are: 1. Gray rami communicantes passing from the ganglion to the 
anterior divisions of the fifth and sixth cervical nerves. 2. The subclavian loop or 
the ansa of Vieussens (ansa subclavia) (Fig. 694) arises from the ganglion, passes 
MIDDLE CERVICAL GANGLION 
SUBCLAVIAN LOOP 
INFERIOR CERVICAL 
GANGLION 
Fig. 694.-The subclavian loop passing from the 
middle to the inferior cervical ganglia. THE CERVICAL PORTION OE THE GANGLIATED CORD 
1077 
down over the front and under the subclavian artery and runs back to join the 
inferior cervical ganglion. It gives branches to the artery. In some cases this 
nerve takes origin from the sympathetic trunk below the ganglion. 
The Peripheral Branches.-The peripheral branches are the thyroid and the 
middle cardiac nerve. 
The Thyroid Branches (Fig. 693) are small filaments which accompany the in- 
ferior thyroid artery to the thyroid gland, forming the inferior thyroid plexus 
{plexus thyreoideus inferior); they communicate, on the artery, with the superior 
cardiac nerve, and, in the gland, with branches from the recurrent and external 
laryngeal nerves. 
'The Middle or Great Cardiac Nerve (n. cardiacus medius) (Figs. 691 and 693), the 
largest of the three cardiac nerves, arises from the middle cervical ganglion or from 
the cord between the middle and inferior ganglia. On the right side it descends 
behind the common carotid artery, and at the root of the neck passes either in 
front of or behind the subclavian artery; it then descends on the trachea, receives 
a few filaments from the recurrent laryngeal nerve, and joins the right side of the 
deep cardiac plexus. In the neck it communicates with the superior cardiac and 
recurrent laryngeal nerves. On the left side the middle cardiac nerve enters the 
chest between the left carotid and subclavian arteries, and joins the left side of 
the deep cardiac plexus. If the middle cervical ganglion is absent, the above- 
named branches arise from the gangliated cord. 
The Inferior Cervical Ganglion (ganglion cervicale inf eri us) (Figs. 691 and 693). 
-The inferior cervical ganglion is situated between the base of the transverse pro- 
cess of the last cervical vertebra and the neck of the first rib on the inner side 
of the superior intercostal artery. Its form is irregular; it is larger in size than the 
preceding, and is frequently joined with the first thoracic ganglion. It is prob- 
ably formed by the coalescence of two ganglia which correspond to the two last 
cervical nerves. It joins the middle ganglion above and the first thoracic ganglion 
below by the commissural cord, and is usually also joined to the middle ganglion 
by the subclavian loop. 
The Central Communicating Branches.-Its central communicating branches are: 
1. Gray rami communicantes passing to the anterior divisions of the seventh and 
eighth cervical nerves (Fig. 693). 2. The subclavian loop (Fig. 694), which has 
been previously described and which passes under and in front of the subclavian 
artery to reach the middle cervical ganglion or the commissural cord. 
The Peripheral Branches.-The peripheral branches are: 1. Vascular. 'The 
vertebral plexus (plexus vertebralis) (Fig. 693) lies upon the vertebral artery and its 
branches in the neck and in the cranial cavity. The subclavian plexus (plexus 
subclavius) (Fig. 693) arises from the subclavian loop, which may be regarded as 
a branch of the inferior or of the middle ganglion. 2. Cardiac. The inferior or 
minor cardiac nerve (n. cardiacus inferior) (Fig. 693) arises from the inferior cervical 
or first thoracic ganglion. It passes down behind the subclavian artery and along 
the front of the trachea to join the deep cardiac plexus. It communicates freely 
behind the subclavian artery with the recurrent laryngeal and middle cardiac nerves. 
Surgical Anatomy.-The situation of the cervical sympathetic makes wounds of it rare. 
Thirteen cases of sympathetic traumatic injury were collected by Seeligmiiller. In ten cases 
paralysis existed; in three, irritation. Tumors of the neck may cause irritation or paralysis. In 
irritation of the sympathetic the corresponding side of the face becomes pale, the pupil dilates, 
the palpebral fissure widens, and the eyeball protrudes. In many cases there is acceleration 
of the heart beats. In paralysis of the sympathetic the pupil contracts, the palpebral fissure is 
narrowed by partial ptosis, the corresponding side of the face reddens, there is an increase in 
the flow of tears, and recession of the eyeball. 
The surgeon occasionally resects the sympathetic. Jonnesco recommends bilateral removal 
of the superior cervical ganglia for glaucoma, and bilateral removal of all the cervical sympa- 
thetic ganglia for epilepsy and for exophthalmic goitre. 1078 
THE NERVOUS SYSTEM 
The Thoracic Portion (Pars Thoracalis) of the Gangliated Cord (Fig. 695). 
The thoracic portion of the gangliated cord consists of a series of ganglia 
which usually correspond in number to that of the vertebrae, but, from the occa- 
sional coalescence of two, their number is uncertain. These ganglia are placed 
on each side of the spine, resting against the heads of the ribs, and are covered by 
. INFERIOR CER- 
VICAL GANGLION 
THORACIC NERVES- 
RAMI COMMUNICANTES- 
VISCERAL 
BRANCHES 
VISCERAL 
BRANCHES 
THORACIC CHAIN 
OF GANGLIA 
RIGHT PNEU- 
- MOGASTRIC 
SPLANCHNIC 
GANGLION ' 
GREAT 
splanchnic' 
SMALL 
SPLANCHN IC 
BRANCH OF PNEUMOGASTRlC 
TO SEMILUNAR GANGLION 
XCELIAC AXIS 
SMALL 
splanchnic' 
SEMILUNAR GANGLION 
SUPERIOR MESENTERIC 
'ARTERY AND PLEXUS 
'SOLAR PLEXUS 
QUADRATUS. 
LUM BORUM 
Fig. 695.-Plan of the right sympathetic cord and splanchnic nerves. (Testut.) 
RENAL PLEXUS 
the pleura costalis; the last two ganglia are, however, anterior to the rest, being 
placed on the side of the bodies of the eleventh and twelfth dorsal vertebrae. The 
ganglia are small in size and of a grayish color. The first ganglion, larger than 
the rest, is of an elongated form and is frequently blended with the last cervical 
ganglion. They are connected together by cord-like prolongations from the sub- 
stance. In the thorax each thoracic or dorsal spinal nerve, with occasionally the 
exception of the first, sends a visceral branch or white ramus communicans to the 
thoracic gangliated cord (Figs. 693 and 695). As Prof. Cunningham points out, THE LUMBAR PORTION OF THE GANGLIATED CORD 
1079 
the white rami "separate into two main streams in relation to the sympathetic 
cord. Those of the upper five nerves are, for the most part, directed upward in 
the gangliated cord to be distributed through the cervical part of the sympathetic 
in the manner already described. The white rami of the lower thoracic nerves 
are, for the most part, directed downward in the lower part of the sympathetic 
cord, and its branches, to be distributed to the abdomen; at the same time some 
of their fibres are directly associated with the supply of certain thoracic viscera- 
lungs, aorta, oesophagus."1 The white rami are composed of splanchnic afferent 
fibres and somatic and splanchnic efferent fibres. 
Central Communicating Branches.-1. White rami communicantes (see above). 
2. Gray rami communicantes arise from each one of the thoracic ganglia, pass back- 
ward with the white rami, and enter into the anterior divisions of the thoracic nerves. 
Peripheral Branches (Fig. 693).-1. Aortic Branches (Fig. 693) come off from the 
first five or six upper ganglia. They send filaments to the aorta and its branches, 
to the vertebral bodies, and to the vertebral ligaments. The aortic branches help 
to form the thoracic aortic plexus (plexus aorticus thoracalis). This plexus is com- 
pleted by branches from the cardiac plexus. 
2. Pulmonary Branches (Fig. 693) come off from the third and fourth and some- 
times from the first and second ganglia. 
3. The Splanchnic Nerves (Figs. 688, 691, and 695).-From the six or seven lower 
ganglia and from the commissural cord a number of large white branches arise. 
They give filaments to the aorta and unite to form the three splanchnic nerves on 
each side. These are named the great, the lesser, and the smallest or renal splanchnic. 
The superior or great splanchnic nerve (n. splanchnicus major) is of a white 
color, firm in texture, and presents a marked contrast to the ganglionic nerves. 
It is formed by branches from the thoracic ganglia between the fifth or sixth 
and the ninth or tenth, but the fibres in the higher roots may be traced upward 
in the sympathetic cord as far as the first or second thoracic ganglion. These 
roots unite to form a large round cord of considerable size. It descends obliquely 
inward in front of the bodies of the vertebrae along the posterior mediastinum, 
perforates the crus of the Diaphragm, and terminates in the semilunar ganglion of 
the solar plexus (Fig. 695), distributing filaments to the renal and suprarenal plexus. 
The middle, lesser or small splanchnic nerve (n. splanchnicus minor) is formed 
by filaments from the tenth and eleventh ganglia, and from the cord between them. 
It pierces the Diaphragm with the preceding nerve, and joins the solar plexus 
(Fig. 695). It communicates in the chest with the great splanchnic nerve, and 
occasionally sends filaments to the renal plexus. 
The inferior, smallest, least or renal splanchnic nerve (n. splanchnicus imus) arises 
from the last thoracic ganglion, and, piercing the Diaphragm, terminates in the 
renal plexus and lower part of the solar plexus. It occasionally communicates with 
the preceding nerve (Fig. 688). 
A striking analogy appears to exist between the splanchnic and the cardiac 
nerves. The cardiac nerves are three in number; they arise from the three cer- 
vical ganglia, and are distributed to a large and important organ in the thoracic 
cavity. The splanchnic nerves, also three in number, are connected probably 
with all the dorsal ganglia, and are distributed to important organs in the abdom- 
inal cavity. 
The Lumbar Portion (Pars Lumbalis) of the Gangliated Cord (Figs. 688, 691). 
The lumbar portion of the gangliated cord is situated in front of the vertebral 
column along the inner margin of the Psoas muscle. It consists usually of four 
1 Text-book of Anatomy. 1080 
THE NERVOUS SYSTEM 
ganglia, but there may be as many as eight, connected together by interganglionic 
cords. The ganglia are of small size, of a grayish color, shaped like a barleycorn, 
and placed much nearer the median line than the thoracic ganglia. Sometimes 
several ganglia are fused together. 
It is connected with the thoracic portion by a thin commissure, which passes 
back of or through the Diaphragm. It is connected with the sacral portion by 
a commissure which is under the common iliac artery. 
The upper lumbar ganglia or the upper portion of the gangliated cord receives 
white rami communicantes from the first two or three lumbar spinal nerves. 
Central Communicating Branches.-Gray rami communicantes pass irregularly from 
the gangliated cord to the anterior divisions of the lumbar spinal nerves, the gray 
rami accompanying the white rami. 
From the situation of the lumbar ganglia these branches are longer than in the 
other regions. They are usually two in number from each ganglion, but their 
connection with the spinal nerves is not so uniform as in other regions. They 
accompany the lumbar arteries around the sides of the bodies of the vertebrae, 
passing beneath the fibrous arches from which some of the fibres of the Psoas 
muscle arise. 
Peripheral Branches.-Some branches pass inward, in front of the aorta, and 
help to form the abdominal aortic plexus (plexus aorticus abdominalis) (Fig. 691), 
which plexus is, however, developed chiefly by filaments from the coeliac plexus. 
Other branches descend in front of the common iliac arteries, and join over the 
promontory of the sacrum, helping to form the hypogastric plexus (plexus hypo- 
gastricus) (Fig. 691). Numerous delicate filaments are also distributed to the 
bodies of the vertebrae and the ligaments connecting them, 
o o 
Pelvic or Sacral Portion (Pars Sacralis) of the Gangliated Cord (Figs. 688,691). 
The pelvic portion of the gangliated cord is situated in front of the sacrum 
along the inner side of the anterior sacral foramina. It consists of four or five 
small ganglia on each side, connected together by interganglionic cords. Below, 
these cords converge and unite on the front of the coccyx by means of a small 
ganglion, the coccygeal ganglion or ganglion impar (ganglion coccygeum impar) 
(Fig. 691). The commissural cord joins the pelvic portion to the lumbar portion 
of the gangliated cord. Like the cervical portion and the lower lumbar portion 
the sacral portion receives no white rami communicantes. 
The visceral branches of the third sacral, and usually of the second and fourth 
sacral spinal nerves, are not connected with the ganglionic cord. 
Central Communicating Branches.-Gray rami communicantes, which arise in the 
sacral ganglia and pass to the anterior divisions of the sacral and coccygeal nerves. 
Peripheral Branches.-1. Visceral branches arise from the upper portion of the 
gangliated cord and pass to the pelvic plexus. 
2. Parietal branches communicate, on the front of the sacrum, with the correspond- 
ing branches from the opposite side; some, from the first two ganglia, pass to join 
the pelvic plexus, and others form a plexus which accompanies the middle sacral 
artery and sends filaments to the coccygeal gland. 
THE GREAT PLEXUSES OF THE SYMPATHETIC (Fig. 688). 
The great plexuses of the sympathetic are the large aggregations of nerves 
and ganglia, previously alluded to, situated in the thoracic, abdominal, and pelvic 
cavities respectively. From them are derived the branches which supply the 
viscera. THE PULMONARY PLEXUS 
1081 
The Cardiac Plexus (Plexus Cardiacus) (Figs. 688, 691). 
The cardiac plexus is situated at the base of the heart, and is divided into a 
superficial part, which lies in the concavity of the arch of the aorta, and a deep 
part, which lies between the trachea and aorta. The two plexuses are, however, 
closely connected. 
The Great or Deep Cardiac Plexus.-The great or deep cardiac plexus, 
the plexus magnus profundus of Scarpa, is situated in front of the trachea at its 
bifurcation, above the point of division of the pulmonary artery and behind the 
arch of the aorta. It is formed by the cardiac nerves derived from the cervical 
ganglia of the sympathetic and the cardiac branches of the recurrent laryngeal 
and 'meumogastric. The only cardiac nerves which do not enter into the forma- 
tion of this plexus are the left superior cardiac nerve and the inferior cervical 
cardiac branch from the left pneumogastric. 
The branches from the right side of this plexus pass, some in front of, and 
others behind, the right pulmonary artery; the former, the more numerous, trans- 
mit a few filaments to the anterior pulmonary plexus, and are then continued 
onward to form part of the left or anterior coronary plexus; those behind the pul- 
monary artery distribute a few filaments to the right auricle, and are then con- 
tinued onward to form a part of the right or posterior coronary plexus. 
The branches from the left side of the deep cardiac plexus distribute a few 
filaments to the superficial cardiac plexus, to the left auricle of the heart, and to 
the anterior pulmonary plexus, and then pass on to form the greater part of the 
posterior coronary plexus. 
The Anterior or Left Coronary Plexus {plexus coronarius cordis anterior).-The 
anterior or left coronary plexus is formed chiefly from the superficial cardiac 
plexus, but receives filaments from the deep cardiac plexus. Passing forward 
between the aorta and pulmonary artery, it accompanies the left coronary artery 
on the anterior surface of the heart. 
The Posterior or Right Coronary Plexus {plexus coronarius cordis posterior).- 
The posterior or right coronary plexus is chiefly formed by filaments prolonged 
from the left side of the deep cardiac plexus, and by a few from the right side. 
It surrounds the branches of the coronary artery at the back of the heart, and 
its filaments are distributed with those vessels to the muscular substance of the 
ventricles. 
The Superficial or AnteriorCardiac Plexus.-The superficial or anterior cardiac 
plexus lies beneath the arch of the aorta, in front of the right pulmonary artery. It 
is formed by the left superior cardiac nerve, the left (and occasionally also the right) 
inferior cervical cardiac branches of the pneumogastric, and filaments from the 
deep cardiac plexus. A small ganglion, the cardiac ganglion of Wrisberg {ganglion 
cardiacum [IPrz.vfrergu]) is occasionally found connected with these nerves at their 
point of junction. This ganglion, when present, is situated immediately beneath 
the arch of the aorta, on the right side of the ductus arteriosus. The superficial 
cardiac plexus forms the chief part of the anterior coronary plexus, and several 
filaments pass along the pulmonary artery to the left anterior pulmonary plexus. 
Valentin has described nervous filaments ramifying under the endocardium; 
and Remak has found, in several mammalia, numerous small ganglia on the car- 
diac nerves, both on the surface of the heart and in its muscular substance. 
The Pulmonary Plexus (Plexus Pulmonalis). 
The larger posterior pulmonary plexus is situated back of the root of the lung. 
It is formed by the pneumogastric nerve and branches from the second, third, and 
fourth thoracic sympathetic ganglia. It sends branches along the bronchi and 1082 
THE NERVOUS SYSTEM 
blood-vessels into the lung and some fibres pass to the front of the root of the 
lung to form the anterior pulmonary plexus. The smaller anterior pulmonary 
plexus is in front of and above the root of the lung. It is formed on each side by 
the fibres from the posterior pulmonary plexus. The left plexus receives branches 
from the superficial cardiac plexus. The anterior plexus supplies the structures 
of the root of the lung. 
The Oesophageal Plexus (Plexus Oesophageus) 
The oesophageal plexus is in the posterior mediastinum and surrounds the 
oesophagus. It is formed by the pneumogastric nerves which have come from 
PHRENIC 
PLEXUS 
SOLAR 
PLEXUS 
LEFT 
PNEUMOGASTRIC 
RIGHT 
PNEUMOGASTRIC 
GASTRIC 
PLEXUS 
PHRENIC 
PLEXUS 
SUPRARENAU 
PLEXUS 
SPLENIC 
PLEXUS 
HEPATIC 
PLEXUS 
COM MON 
BILE-DUCT 
GREAT 
SPLANCHNIC 
SEMILUNAR 
GANGLION 
SUPERIOR 
MESENTERIC 
PLEXUS 
ABDOMINAL 
AORTIC 
PLEXUS 
.RENAL 
PLEXUS 
SUPERIOR 
'MESENTERIC 
GANGLION 
SPERMATIC 
PLEXUS 
lumbar 
ganglia 
INFERIOR 
mesenteric 
PLEXUS 
Fig. 696. The semilunar ganglia with the sympathetic plexuses of the abdominal viscera radiating from 
the ganglia. (Toldt.) 
the posterior pulmonary plexuses, and by fibres from the great splanchnic nerve 
and ganglion. The oesophageal plexus is usually considered as a portion of the 
pneumogastric nerve (p. 1061). THE EPIGASTRIC OR SOLAR PLEXUS 
1083 
The Epigastric or Solar Plexus (Plexus Coeliacum) (Figs. 688, 691, 696, 697). 
The epigastric or solar plexus supplies all the viscera in the abdominal cavity. 
It consists of a great network of nerves and ganglia, situated behind the pancreas 
Diaphragmatic ganglion. 
Hepatic 
artery. 
Suprarenal capsule. 
'Left semilunar ganglion. 
Superior mesenteric artery. 
Great 
splanchnic 
nerve. 
Great splanchnic nerve. 
.Small splanchnic nerve. 
Right 
semilunar 
ganglion. 
■Renal ganglion. 
Renal ganglion.. 
Small splanchnic nerve. 
Renal artery. 
Renal artery. 
Superior mesenteric ganglion. 
Gangliated cord: 
Communicating branch: 
■Branch to aortic plexus. 
Gangliated cord of 
sympathetic. 
Branch to aortic plexus.- 
Inferior mesenteric artery. 
.Inferior mesenteric ganglion. 
Sacro-vertebral angle. 
Common iliac vein. 
■Common iliac artery. 
Fig. 697.-Lumbar portion of the gangliated cord, with the solar and hypogastric plexuses. (After Henle.) 1084 
THE NERVOUS SYSTEM 
and the lesser peritoneal cavity and in front of the aorta and crura of the Dia- 
phragm. It surrounds the coeliac axis and root of the superior mesenteric artery, 
extending downward as low as the pancreas and outward to the suprarenal cap- 
sules. This plexus, and the ganglia connected with it, receive the great, the small 
and the least splanchnic nerves of both sides, and some filaments from the right 
pneumogastric nerve. It distributes filaments which accompany, under the name 
of plexuses, all the branches from the front of the abdominal aorta. 
Of the ganglia of which the solar plexus is partly composed the principal are 
the two semilunar ganglia (ganglia coeliaca) (Figs. 688, 696, and 697), which are 
situated one on each side of the plexus, and are the largest ganglia in the body. 
They are large, irregular, gangliform masses formed by the aggregation of smaller 
ganglia, having interspaces between them. They are situated in front of the 
crura of the Diaphragm, close to the suprarenal capsules: the one on the right 
side lies beneath the inferior vena cava; the upper part of each ganglion is joined 
by the greater splanchnic nerve, and to the inner side of each the branches of the 
solar plexus are connected. 
From the epigastric or solar plexus are derived the following: 
Phrenic or Diaphragmatic plexus. 
Suprarenal plexus. 
Renal plexus. 
Spermatic plexus. 
Gastric plexus. 
Splenic plexus. 
Hepatic plexus. 
Coeliac plexus 
Superior mesenteric plexus. 
Aortic plexus. 
The Phrenic Plexus (plexus phrenicus) (Fig. 696).-The phrenic plexus accom- 
panies the phrenic artery to the Diaphragm, which it supplies, some filaments 
passing to the suprarenal capsule. It arises from the upper part of the semilunar 
ganglion, and is larger on the right than on the left side. It receives one or two 
branches from the phrenic nerve. In connection with this plexus, on the right 
side, at its point of junction with the phrenic nerve, is a small ganglion, the 
diaphragmatic or phrenic ganglion (ganglion phrenicum) (Fig. 697). This ganglion 
is placed on the under surface of the Diaphragm, near the right suprarenal capsule. 
Its branches are distributed to the inferior vena cava, suprarenal capsule, and 
hepatic plexus. There is no ganglion on the left side. 
The Suprarenal Plexus (plexus suprarenalis) (Fig. 696).-The suprarenal plexus 
is formed by branches from the solar plexus, from the semilunar ganglion, and 
from the phrenic and great splanchnic nerves, a ganglion being formed at the 
point of junction of the latter nerve. It supplies the suprarenal capsule. The 
branches of this plexus are remarkable for their large size in comparison with 
the size of the organ they supply. 
The Renal Plexus (plexus renalis) (Figs. 696 and 697).-The renal plexus is 
formed by filaments from the 'Solar plexus, the outer part of the semilunar 
ganglion, and the aortic plexus. It is also joined by filaments from the lesser and 
smallest splanchnic nerves. The nerves from these sources, fifteen or twenty in num- 
ber, have numerous ganglia developed upon them. They accompany the branches 
of the renal artery into the kidney, some filamentson the right side being distributed 
to the inferior vena cava, and others, on both sides, to the spermatic plexuses. 
The Spermatic Plexus (plexus spermaticus') (Fig. 696).-The spermatic plexus 
is derived from the renal plexus, receiving branches from the aortic plexus. It 
accompanies the spermatic vessels to the testes. 
The Ovarian Plexus (plexus arteriae ovaricae).-Tn the female the ovarian plexus 
is distributed to the ovaries and fundus of the uterus. 
The Coeliac Plexus (plexus coeliacus}.-The coeliac plexus, of large size, is a 
direct continuation from the solar plexus; it surrounds the coeliac axis and sub- 
divides into the gastric, hepatic, and splenic plexuses. It receives branches from THE HYPOGASTRIC PLEXUS 
1085 
the lesser splanchnic nerves, and, on the left side, a filament from the right pneu- 
mogastric. 
The Gastric or Coronary Plexus {plexus gastricus superior) (Fig. 696) accompanies 
the gastric artery along the lesser curvature of the stomach, and joins with branches 
from the left pneumogastric nerve. It is distributed to the stomach. 
The Splenic Plexus {plexus lienalis) (Fig. 696) is formed by branches from the 
cceliac plexus, the left semilunar ganglion, and from the right pneumogastric 
nerve. It accompanies the splenic artery and its branches to the substance of 
the spleen, giving off, in its course, filaments to the pancreas, the pancreatic plexus, 
and the left gastro epiploic plexus, which accompanies the gastro-epiploica sinistra 
artery along the convex border of the stomach. 
The Hepatic Plexus {plexus hepaticus) (Fig. 696), the largest offset from the 
coeliac plexus, receives filaments from the left pneumogastric and right phrenic 
nerves. It accompanies the hepatic artery, ramifying in the substance of the liver 
upon its branches and upon those of the vena portae. 
Branches from this plexus accompany all the divisions of the hepatic artery. 
Thus there is a pyloric plexus accompanying the pyloric branch of the hepatic, 
which joins with the gastric plexus and pneumogastric nerves. There is also a 
gastro-duodenal plexus, which subdivides into the pancreatico-duodendal plexus, 
which accompanies the pancreatico-duodenal artery, to supply the pancreas and 
duodenum, joining with branches from the mesenteric plexus. The gastro-epi- 
ploic plexus, which accompanies the right gastro-epiploic artery along the greater 
curvature of the stomach, and which is said to anastomose with branches from 
the splenic plexus, is in reality derived from the splenic plexus. A cystic plexus, 
which supplies the gall-bladder, also arises from the hepatic plexus near the liver. 
The Superior Mesenteric Plexus {plexus mesentericus superior) (Fig. 696).-The 
superior mesenteric plexus is a continuation of the lower part of the great solar 
plexus, receiving a branch from the junction of the right pneumogastric nerve with 
the coeliac plexus. It surrounds the superior mesenteric artery, which it accom- 
panies into the mesentery, and divides into a number of secondary plexuses, which 
are distributed to all the parts supplied by the artery-viz., pancreatic branches to 
the pancreas; intestinal branches, which supply the whole of the small intestine; 
and ileo-colic, right colic, and middle colic branches, which supply the corresponding 
partsof the large intestine. The nerves composing this plexus are white in color and 
firm in texture, and have numerous ganglia developed upon them near their origin. 
The Abdominal Aortic Plexus {plexus aorticus abdominalis) (Figs. 691, 696, and 
697).-The abdominal aortic plexus is formed by branches derived, on each side, 
from the solar plexus and the semilunar ganglia, receiving filaments from some 
of the lumbar ganglia. It is situated upon the sides and front of the aorta, 
between the origins of the superior and inferior mesenteric arteries. From this 
plexus arise part of the spermatic, the inferior mesenteric, and the hypogastric 
plexuses; and it distributes filaments to the inferior vena cava. 
The Inferior Mesenteric Plexus {plexus mesentericus inferior) (Fig. 696) is derived 
chiefly from the left side of the aortic plexus. It surrounds the inferior mesenteric 
artery, and divides into a number of secondary plexuses, which are distributed to 
all the parts supplied by the artery-viz., the left colic and sigmoid plexuses, which 
supply the descending and sigmoid flexure of the colon; and the superior haem- 
orrhoidal plexus {plexus haemorrhoidalis superior), which supplies the upper part 
of the rectum and joins in the pelvis with branches from the pelvic plexus. 
The Hypogastric Plexus (Plexus Hypogastricus) (Figs. 688, 691, 697). 
The hypogastric plexus supplies the viscera of the pelvic cavity. It is situated 
in front of the promontory of the sacrum, between the two common iliac arteries, THE NERVOUS SYSTEM 
1086 
and is formed by the union of numerous filaments, which descend on each side 
from the abdominal aortic plexus and from the lumbar ganglia. This plexus con- 
tains no evident ganglia; it bifurcates, below, into two lateral portions, which 
form the pelvic plexuses. 
The Pelvic or Sacral Plexus (Plexus Sacralis). 
The pelvic plexus, sometimes called the inferior hypogastric, supplies the viscera 
of the pelvic cavity, is situated at the side of the rectum in the male, and at the 
side of the rectum and vagina in the female. It is formed by a continuation of the 
hypogastric plexus, by branches from the second, third, and fourth sacral nerves, 
and by a few filaments from the first two sacral ganglia. At the point of junction 
of these nerves small ganglia are found. From this plexus numerous branches are 
distributed to all the viscera of the pelvis. They accompany the branches of the 
internal iliac artery. 
The Inferior Haemorrhoidal Plexus (plexus haemorrhoidalis inferior).-The infe- 
rior haemorrhoidal plexus arises from the back part of the pelvic plexus. It 
supplies the rectum, joining with branches of the superior haemorrhoidal 
plexus. 
The Vesical Plexus (plexus vesicalis).-The vesical plexus arises from the fore- 
part of the pelvic plexus. The nerves composing it are numerous, and contain 
a large proportion of spinal nerve-fibres. They accompany the vesical arteries, 
and are distributed at the side and base of the bladder. Numerous filaments also 
pass to the vesiculae seminales and vasa deferentia; those accompanying the vas 
deferens join, on the spermatic cord, with branches from the spermatic plexus. 
The Prostatic Plexus (plexus prostaticus).-The prostatic plexus is continued 
from the lower part of the pelvic plexus. The nerves composing it are of large 
size. They are distributed to the prostate gland, vesiculae seminales, and erectile 
structure of the penis. The nerves supplying the erectile structure of the penis 
consist of two sets, the small and large cavernous nerves. They are slender fila- 
ments, which arise from the forepart of the prostatic plexus, and, after joining 
with branches from the internal pudic nerve, pass forward beneath the pubic 
arch. 
The Small Cavernous Nerve (n. cavernosus penis minor) perforates the fibrous 
covering of the penis near its roots. 
The Large Cavernous Nerve (n. cavernosus penis major) passes forward along the 
dorsum of the penis, joins with the dorsal branch of the pudic nerve, and is dis- 
tributed to the corpora cavernosa and corpus spongiosum. 
The uterine and vaginal plexuses in reality constitute one plexus, the utero- 
vaginal plexus (plexus uterovaginalis). 
The Vaginal Plexus arises from the lower part of the pelvic plexus. It is lost 
on the walls of the vagina, being distributed to the erectile tissue at its anterior 
part and to the mucous membrane. 'The nerves composing this plexus contain, 
like the vesical nerves, a large proportion of spinal nerve-fibres. 
The Uterine Plexus arises from the upper part of the pelvic plexus above the 
point where the branches from the sacral nerves join the plexus. Its branches 
accompany the uterine arteries to the sides of the organ between the layers of the 
broad ligaments, and are distributed to the cervix and lower part of the body of 
the uterus, penetrating its substance. 
Other filaments pass separately to the body of the uterus and the Fallopian 
tube. 
Branches from the plexus accompany the uterine arteries into the substance 
of the uterus. Upon these filaments ganglionic enlargements are found. THE ORGANS 0E SPECIAL SENSE. 
THE Organs of the Senses are five in number-viz., those of Taste, of Smell, 
of Sight, of Hearing, and of Touch. 
THE TONGUE (LINGUA) (Fig. 698). 
The tongue is a very mobile muscular organ, undergoing changes in length and 
width at every contraction of its muscle. It is the organ of the special sense of 
taste, and is also an organ of speech, mastication, and deglutition. It is situated 
in the floor of the mouth, in the interval between the two lateral portions of the 
body of the lower jaw, and when at rest is about three and one-half inches in 
length. We describe the body, base, apex, dorsum, margin, and inferior surface. 
The Body {corpus linguae).-The body forms the great bulk of the organ 
and is composed of striated muscle. 
The Base or Root {radix linguae).-The base or root is directed backward, and 
connected with the os hyoideum by the Hyo-glossi and Genio-hyo-glossi muscles 
and the hyo-glossal membrane; with the epiglottis by three folds of mucous mem- 
brane, the glosso-epiglottic folds; with the soft palate by means of the anterior 
pillars of the fauces; and with the pharynx by the Superior constrictors and the 
mucous membrane. 
The Apex or Tip {apex linguae).-The apex or tip is thin and narrow, and is 
directed forward against the inner surface of the lower incisor teeth. 
The Dorsum of the Tongue {dorsum linguae).-The dorsum when the tongue 
of a living person is at rest is markedly arched from before backward. On the 
dorsum is a median longitudinal raphS {sulcus medianus linguae). This slight 
depression terminates posteriorly in the depression known as the foramen caecum 
{foramen caecum linguae [Morgagnity, from which a shallow-shaped groove, the 
sulcus terminalis of His, runs outward and forward on each side to the lateral 
margin of the tongue. The part of the dorsum of the tongue in front of this 
groove, known as the anterior or oral part, forming about two-thirds of its upper 
surface, is rough and covered with papillae; the posterior third of the dorsum 
is back of the sulcus terminalis, is known as the posterior or pharyngeal portion, is 
smoother, and contains numerous muciparous glands and lymphoid follicles. 
The Margin of the Tongue {margo lateralis linguae).-The margin of the 
tongue is free in front of the anterior arch of the palate. Just in front of the 
arch are several vertical folds, the folia linguae. 
The Under or Inferior Surface {facies inferior linguae).-The under or 
inferior surface of the tongue is connected with the lower jaw by the Genio-hyo- 
glossi muscles, from its sides the mucous membrane is reflected to the inner sur- 
face of the gums; and from its under surface on to the floor of the mouth, where, 
in the middle line, it is elevated into a distinct vertical fold, the fraenum linguae 
{frenulum linguae). To each side of the fraenum is a slight fold of the mucous 
membrane, the plica fimbriata, the free edge of which exhibits a series of fringe- 
like processes. 
The tip of the tongue, part of the under surface, its sides, and dorsum are free. 
1087 THE ORGANS OF SPECIAL SENSE 
1088 
Structure of the Tongue.-The tongue is partly invested by mucous mem- 
brane and a submucous fibrous layer. It consists of symmetrical halves, sepa- 
rated from each other, in the middle line, by a fibrous septum. Each half is com- 
posed of muscular fibres arranged in various directions (page 398), containing 
much interposed fat, and supplied by vessels and nerves. 
The Mucous Membrane (tunica mucosa linguae).-The mucous membrane 
invests the entire extent of the free surface of the tongue. On the dorsum it is 
thicker behind than in front, and is continuous with the sheath of the muscles 
attached to it, through the submucous fibrous layer. On the under surface of the 
organ, where it is thin and smooth, it can be traced on each side of the fraenum 
UVULA. 
PHARYNX 
-TONSIL. 
-EPIGLOTTIS. 
CIRCU M- 
VALLATE 
PAPILUE. 
Fig. 698.-Upper surface of the tongue. 
through the ducts of the submaxillary and the sublingual glands. As it passes 
over the borders of the organ it gradually assumes a papillary character. 
Structure.-The structure of the mucous membrane of the tongue differs in 
different parts. That covering the under surface of the organ is thin, smooth, 
and identical in structure with that lining the rest of the oral cavity. The mucous 
membrane covering the tongue behind the foramen caecum and sulcus terminalis 
is thick and freely movable over the subjacent parts. It contains a large number 
of lymphoid follicles (jolliculi linguales), which together constitute what is some- 
times termed the lingual tonsil (tonsilla Hngualis). Each follicle forms a rounded 
eminence, the centre of which is perforated by a minute orifice leading into a THE TONGUE 
1089 
funnel-shaped cavity or recess; around this recess are grouped numerous oval or 
rounded nodules of lymphoid tissue, each enveloped by a capsule derived from 
the submucosa, while opening into the bottom of the recesses are also seen the 
ducts of mucous glands (glandulae linguales). The mucous membrane on the 
anterior part of the dorsum of the tongue is thin and intimately adherent to the 
muscular tissue, and covered with minute eminences, the papillae of the tongue. 
It consists of a layer of connective tissue, the corium or mucosa, supporting numer- 
ous papillae, and covered, as well as the papillae, with epithelium. 
The epithelium is of the scaly variety, like that of the epidermis. It covers the 
free surface of the tongue, as maybe readily demonstrated by maceration or boiling, 
when it can be easily detached entire; it is much thinner than that of the skin; the 
intervals between the large papillae are not filled up by it, but each papilla has 
a separate investment from root to summit. The deepest cells may sometimes be 
detached as a separate layer, corresponding to the rete mucosum, but they never 
contain coloring matter. 
The Corium.-The corium consists of a dense feltwork of fibrous connective 
tissue, with numerous elastic fibres, firmly connected with the fibrous tissue form- 
ing the septa between the muscular bundles of the tongue. It contains the ramifi- 
cations of the numerous vessels (Fig. 699) and nerves from which the papillae are 
supplied, large plexuses of lymphatic vessels, and the glands of the tongue. 
Filiform. 
Fungiform. 
Secondary 
papillae. 
Circumvallate. 
Artery. 
Vein. 
Artery. 
tVein. 
Fig. 699.-Three kinds of papillae, magnified 
The Papillae of the Tongue (papillae linguales) (Figs. 698, 699, 700, and 701).- 
These are papillary projections of the corium. They are thickly distributed over 
the anterior two-thirds of the upper surface of the tongue, giving to it its char- 
acteristic roughness. The varieties of papillae met with are-the papillae maximae 
or circumvallate papillae, papillae mediae or fungiforme papillae, papillae minimae, 
conical or filiforme papillae, and papillae simplices or simple papillae. 
The Papillae Maximae or Circumvallate Papillae (papillae vallatae) (Figs. 698, 699, 
and 700) are of large size, and vary from eight to twelve in number. They are 
situated at the back part of the dorsum of the tongue, near its base, in front of 
the foramen caecum and sulcus terminalis, forming a row on each side, which, 
running backward and inward, meet in the middle line, like the two lines of the 
letter A inverted A. Each papilla consists of a projection of mucous membrane 
from to °f an inch wide, attached to the bottom of a cup-shaped depression of 
the mucous membrane; the papilla is in shape like a truncated cone, the smaller 
end being directed downward and attached to the tongue, the broader part or 
base projecting on the surface and being studded with numerous small secondary 
papillae (Fig. 699), which, however, are covered by a smooth layer of the epithe- 
lium. The cup-shaped depression forms a kind of fossa around the papilla, 
having a circular margin of about the same elevation covered with smaller papillae. THE ORGANS' OF SPECIAL SENSE 
1090 
Immediately behind the apex of the V is the foramen caecum, mentioned above. 
This foramen, according to His, represents the remains of the invagination which 
forms the median rudiment of the thyroid body, and which for a time opens by 
a duct, the thyroglossal duct, on to the dorsum of the tongue. It may extend 
downward toward the hyoid bone. Kanthack, however, disputes this view.1 
The Fungiform Papillae or Papillae Mediae {papillae jungijormes et papillae len- 
ticulares') (Fig. 699), more numerous than the preceding, are scattered irregularly 
and sparingly over the dorsum of the tongue, but are found chiefly at its sides 
and apex. They are easily recognized among the other papillae, by their large 
size, rounded eminences, and deep-red color. They are narrow at their attach- 
ment to the tongue, but broad and rounded at their free extremities, and are 
covered with secondary papillae. Their epithelial investment is very thin. 
The Conical or Filiform Papillae or Papillae Minimae {papillae conicae et papillae 
filiformes) (Fig. 699) cover the anterior two-thirds of the dorsum of the tongue. 
They are very minute, more or less conical or filiform in shape, and arranged in lines 
corresponding in direction with the two rows of the papillae circumvallatae, except- 
ing at the apex of the organ, where their direction is transverse. Projecting from their 
apices are numerous filiform processes or secondary papillae; these are of a whitish 
tint, owing to the thickness and density of the epithelium of which they are com- 
posed, and which has here undergone a 
peculiar modification, the cells having be- 
come cornified and elongated into dense, 
imbricated, brush-like processes. They 
contain also a number of elastic fibres, which 
render them firmer and more elastic than 
the papillae of mucous membrane generally. 
Simple Papillae, similar to those of the skin, 
cover the whole of the mucous membrane of 
the tongue, as well as the larger papillae. 
They consist of closely set, microscopic ele- 
vations of the corium, containing a capillary 
loop, covered by a layer of epithelium. 
Structure of the Papillae (Figs. 699 and 700). 
-The papillae apparently resemble in struc- 
ture the papillae of the cutis, consisting of a 
cone-shaped projection of connective tissue, 
covered with a thick layer of squamous epi- 
thelium, and contain one or more capillary 
loops, amongst which nerves are distributed 
in great abundance. If the epithelium is 
removed, it will be found, however, that they are not simple elevations like the 
papillae of the skin, for the surface of each is studded with minute conical pro- 
cesses of the mucous membrane, which form secondary papillae (Todd and Bow- 
man). In the papillae circumvallatae the nerves are numerous and of large size; in 
the papillae fungiformes they are also numerous, and terminate in a plexiform net- 
work, from which brush-like branches proceed; in the papillae filiformes their mode 
of termination is uncertain. Buried in the epidermis of the papillae circumvallatae, 
and in some of the fungiformes, are certain peculiar bodies, called taste-buds2 (Fig. 
701). Each is flask-like in shape, the broad base resting on the corium, and the 
neck opening by an orifice, the gustatory pore, between the cells of the epithelium. 
Fig. 700.-Circumvallate papillae of tongue of 
rabbit, showing position of taste-goblets. a. 
Duct of gland, d. Serous gland, g. Taste-buds. 
I. Primary septa, and I', secondary septa, of 
papillae, n. Medullated nerve. -V Muscular 
fibres. (Stohr.) 
1 Journal of Anatomy and Physiology, 1891. 
2 These bodies are also found in considerable numbers at the side of the base of the tongue, just in front of the 
anterior pillars of the fauces, and also on the posterior surface of the epiglottis and anterior surface of the soft 
palate.-Ed. of 15th English edition. THE TONGUE 
1091 
They are formed by two kinds of cells, supporting cells and gustatory cells. The 
supporting cells are mostly arranged like the staves of a cask, and form an outer 
envelope for the bud. Some, however, are found in the interior of the bud between 
the gustatory cells. The gustatory cells occupy the central portion of the bud; 
they are spindle-shaped, and each possesses a large spherical nucleus near the 
middle of the cell. Until recently the teaching was as follows: The peripheral 
end of the cell terminates as the gustatory pore in a fine, hair-like filament, the 
gustatory hair. The central process passes toward the deep extremity of the bud, 
and there ends in a single or bifurcated varicose filament, which was formerly 
supposed to be continuous with the terminal fibril of a nerve; the investigations 
of Lenhossek and others would seem to prove, however, that this is not so, but 
that the nerve-fibrils after losing their medullary sheaths enter the taste-bud, and 
Gustatory hairs 
Taste pore 
Epithelium- 
Taste bud- 
Tunica propria 
Fig. 701.-Taste-buds from the papilla foliata of a rabbit. X 850. (Szymonowicz.) 
terminate in a fine extremity between the gustatory cells. Other nerve-fibrils 
may be seen ramifying between the cortical cells and terminating in fine extrem- 
ities; these, however, are believed to be nerves of ordinary sensation, and not 
gustatory. It is now not believed that the epithelia of the taste-buds are directly 
connected with the nerve-fibres by long processes. "The latest researches have 
shown that dendrites of sensory neurones (sensory nerves) enter the taste-buds 
and end free in telodendria. The latter surround the neuro-epithelial, and, to 
some extent, the sustentacular cells, their relations depending on contact.''1 
Glands of the Tongue.-The tongue is provided with mucous and serous glands. 
The mucous glands are similar in structure to the labial and buccal glands. They 
are found especially at the back part, behind the circumvallate papillae, but are 
also present at the apex and marginal parts. In connection with these glands 
special ones have been described by Blandin and Nuhn. They are known as the 
glands of Nuhn and Blandin or apical glands (glandulae linguales anteriores of Nuhn 
and Blandin) (Fig. 702). They are situated near the apex of the tongue on either 
side of the fraenum, and each is covered over by a fasciculus of muscular fibre 
derived from the Stylo-glossus and Inferior lingualis muscles. Each gland is from 
half an inch to nearly an inch long and about the third of an inch broad. It has 
from four to six ducts, which open on the under surface of the apex. 
The Serous Glands or Glands of v. Ebner occur only at the back of the tongue in 
the neighborhood of the taste-buds, their ducts opening for the most part into the 
1 Text-book of Histology. By A. A. Bohm and M. von Davidoff. Edited by G. Carl Huber. 1092 
THE ORGANS OF SPECIAL SENSE 
fossae of the papillae circumvallatae. These glands are racemose, the duct branch- 
ing into several minute ducts, which terminate in alveoli lined by a single layer 
of more or less columnar epithelium. Their secretion is of a watery nature, and 
probably assists in the distribution of the substance to be tasted over the taste- 
area (Ebner). 
The Hyo-glossal membrane is a strong fibrous lamina which is derived from the 
septum of the tongue and which connects the under surface of the base of the 
tongue to the body of the hyoid bone. This membrane receives, in front, some 
of the posterior fibres of the Genio-hyo-glossi muscles. 
The Vessels of the Tongue.-The arteries of the tongue are derived from the 
lingual, the facial, and ascending pharyngeal. The veins of the tongue open into 
the internal jugular. 
The lingual artery (Fig. 704) on each side passes forward beneath the Hyo- 
glossus muscle and courses to the apex of the tongue, between the Genio-glossus 
and the Inferior lingual muscles, about one-eighth of an inch from the surface. 
It divides into the ranine (Fig.702 ) and sublingual (Fig. 704). Near the apex a 
branch is given oft' from the ranine artery, which penetrates the septum and joins 
a like branch from the other side. The dorsalis linguae is a branch of the lingual 
.Bristles 
in ducts 
of glands. 
Glands of 
Blandin 
or Nuhn. 
Lingual nerve. 
Ranine artery. 
Fig. 702.-Under surface of tongue, showing position and relations of gland of Blandin or Nuhn. (From 
a preparation in the Museum of the Royal College of Surgeons of England.) 
supplying the posterior part of the tongue, and rami from the tonsillar branch 
of the facial go to the same region. A network of capillary vessels is placed 
beneath the epithelium. 
The ranine veins lie to the sides of the fraenum underneath the mucous mem- 
brane. Each ranine vein runs backward, superficial to and upon the Hyo-glossus 
muscle and near to the hypo-glossal nerve. The venae comites of the lingual artery 
usually join the ranine vein, and the trunk opens into the internal jugular vein, 
but the vessels may open separately into the jugular (Fig. 445). 
The Muscles of the Tongue.-The muscular fibres of the tongue run in various 
directions. These fibres are divided into two sets, Extrinsic and Intrinsic, which 
have already been described (pp. 396, 397, 398, 399, and 400). THE TONGUE 
1093 
The Extrinsic come from the Stylo-glossus, Hyo-glossus, Genio-glossus, 
Palato-glossus, and Chondro-glossus. The Intrinsic muscles are the Superior 
lingualis (m. longitudinalis superior), the Inferior lingualis (m. longitudinalis 
inferior), the Transverse lingual (m. transversus linguae), and the Vertical lingual 
(m. verticalis linguae). The outer or cortical portion of the tongue is composed 
chiefly of longitudinal fibres. The central or medullary portion is composed chiefly 
of vertical and transverse fibres and is divided into two parts by a vertical sep- 
tum {septum linguae), which is a fibrous structure, beginning at the apex and 
passing back. As it approaches the back it becomes narrower vertically and 
broadens out transversely to form the hyo-glossal membrane. The fibrous septum 
is well displayed by making a vertical section of the tongue. 
The Lymphatic Vessels of the Tongue (Fig. 491).-The lymphatic vessels from 
the anterior half of the tongue pass to the submaxillary lymph glands. 
Lymph vessels from the posterior half of the tongue are connected with satellite 
glands on the Hyo-glossus muscle and terminate in the deep cervical glands. The 
last-named lymph-vessel accompanies the ranine vein. The lingual lymphatics 
arise from a network beneath the epithelium. Across the anterior two-thirds 
of the tongue there is little or no lymphatic connection between the two sides; 
in the posterior one-third there is free connection. 
SUPERIOR 
LONGITUDI NALIS 
MUSCLE 
STYLOGLOSSUS 
MUSCLE 
VERTICALIS. 
LINGUXE MUSCLE 
SEPTUM 
TRANSVERSUS 
LINGUAE MUSCLE 
IN FERIOR 
LONGITUDI N A LIS 
MUSCLE 
DEEP LINGUAL 
ARTERY 
SUBLI NGUAL 
GLAND 
LINGUAL. 
NERVE 
GENIOGLOSSUS 
MUSCLE 
Fig. 703.-Frontal section through the body of the tongue of a new-born babe. X 3. (Spalteholz.) 
The Nerves of the Tongue (Fig. 704).-The nerves of the tongue are five in num- 
ber in each half; the lingual branch of the inferior maxillary division of the fifth, 
which is distributed to the papillae at the forepart and sides of the tongue, and 
forms the nerve of ordinary sensibility for its anterior two-thirds; the chorda 
tympani, which runs in the sheath of the lingual, is generally regarded as the 
nerve of taste for the same area; the lingual branch of the glosso-pharyngeal, which 
is distributed to the mucous membrane at the base and sides of the tongue, and 
to the papillae circumvallatae, and which supplies both sensory and gustatory 
filaments to this region; the hypo-glossal nerve, which is the motor nerve to the 
muscular substance of the tongue; and the internal laryngeal branch of the superior 
laryngeal, which sends some fine branches to the root near to the epiglottis. 
Sympathetic filaments also pass to the tongue from the nervi molies on the 
lingual and other arteries supplying it. Some of the nerves end free between the 
cells of epithelium; others terminate as end organs (Meissner's corpuscles and 
the end-bulbs of Krause), and in taste-buds as sensory dendrites. 
Surgical Anatomy.-The diseases to which the tongue is liable are numerous, and its sur- 
gical anatomy is of importance, since any or all the structures of which it is composed-muscles, 
connective tissue, mucous membrane, glands, vessels, nerves, and lymphatics-may be the seat 
of morbid changes. It is not often the seat of congenital defects, though a few cases of vertical 1094 
THE ORGANS OF SPECIAL SENSE 
clejt have been recorded, and it is occasionally, though much more rarely than is commonly sup- 
posed, the seat of tongue-tie, from shortness of the fraenum. 
There is, however, one condition which must be regarded as congenital, though not uncom- 
monly it does not exhibit the significant changes until a year or two after birth. This is an 
enlargement of the tongue which is due primarily to a dilatation of the lymph-channels and a 
greatly increased development of the lymphatic tissue throughout the tongue (macroglossia). This 
is often aggravated by inflammatory changes induced by injury or exposure, and the tongue may 
assume enormous dimensions and hang out of the mouth, giving the child an imbecile expression. 
The treatment consists in excising a V-shaped portion and bringing the cut surfaces together 
with deeply placed silver sutures. Compression has been resorted to in some cases with occa- 
sional success, but it is difficult to apply. Acute inflammation of the tongue [acute glossitis), 
which may be caused by injury or the introduction of some septic or irritating matter, and it 
is attended by great swelling from infiltration of the connective tissue of the tongue; this con- 
nective tissue is present in considerable quantity. The great swelling renders the patient 
incapable of swallowing or speaking, and may seriously impede respiration. The condition may 
eventuate in suppuration and the formation of an acute abscess. Chronic abscess, which has 
been mistaken for cancer, may also occur in the substance of the tongue. 
Sublingual 
artery. 
Submaxillary 
ganglion. 
Hypo-glossal 
nerve. 
Glosso-pharyn- 
geal nerve. 
Lingual 
artery. 
Lingual 
artery. 
Internal laryngeal 
branch of the 
superior laryngeall 
nerve. 
Fig. 704.-Under surface of tongue, showing the distribution of nerves to this organ. (From a preparation 
in the Museum of the Royal College of Surgeons of England.) 
The mucous membrane of the tongue may become chronically inflamed, and presents different 
appearances in different stages of the disease, to which the terms leucoplakia, psorias, and 
ichthyosis have been given. 
The tongue, being very vascular, is often the seat of naevoid growths, and these have a tendency 
to grow rapidly. 
fhe tongue is frequently the seat of ulceration, which may arise from many causes, as from 
the irritation of jagged teeth, dyspepsia, tuberculosis, syphilis, and cancer. ()f these the cancerous 
ulcer is the most important, and probably also the most common. The variety is the squamous 
epithelioma, which soon develops into an ulcer with an indurated base. It produces great pain, 
which speedily extends to all parts supplied with sensation by the fifth nerve, especially to the THE NOSE 
region of the ear. The pain in these cases is conducted to the ear and temporal region by the 
lingual nerve, and from this nerve pain radiates to the other branches of the inferior maxillary 
nerve, especially the auriculo-temporal. Possibly pain in the ear itself may be due to implication 
of the fibres of the glosso-pharyngeal nerve, which by its tympanic branch reaches the tympanic 
plexus. Cancer of the tongue spreads through the organ very rapidly because of the almost 
constant muscular movements. 
Cancer of the tongue may necessitate removal of a part or the whole of the organ, and many 
different methods have been adopted for its excision. It may be removed from the mouth by 
the ecraseur or the scissors. The better method is by the scissors, usually known as Whitehead's 
method. The mouth is widely opened with a gag. the tongue is transfixed with a stout silk liga- 
ture, by which to hold and make traction on it and the reflection of mucous membrane from 
the tongue to the jaw, and the insertion of the Genio-hyo-glossi first divided with a pair of 
curved blunt scissors. The Palato-glossi are also divided. The tongue can now be pulled well 
out of the mouth. The base of the tongue is cut through by a series of short snips, each bleed- 
ing vessel being dealt with as soon as divided, until the situation of the ranine artery is reached. 
The remaining undivided portion of tissue is to be seized with a pair of Wells's forceps, the tongue 
removed, and the vessel secured. In the event of the ranine artery being accidentally injured 
early in the operation, hemorrhage can be at once controlled by passing two fingers over the 
dorsum of the tongue as far as the epiglottis and dragging the root of the tongue forcibly forward. 
In cases where the disease is confined to one side of the anterior portion of the tongue this 
operation may be modified by splitting the tongue down the centre and removing only the affected 
half. If the posterior portion of the tongue is attacked by cancer the entire tongue must be 
removed, even if but one side of the organ is apparently involved. The exchange of lymph 
between the halves of the posterior portion of the tongue makes it certain that the opposite half 
becomes involved soon after the origin of the disease. Whatever operation is performed for 
cancer of the tongue, the glands must be removed from both sides of the neck. This is to be 
done, even if but one side of the tongue is removed. Kocher, after performing a preliminary trache- 
otomy, removes the tongue from the neck; by an incision taken from near the lobule of the ear, 
down the anterior border of the Sterno-mastoid to the level of the great cornu of the hyoid bone, 
then forward to the body of the hyoid bone, and upward to near the symphysis of the jaw. The 
lingual artery is now secured, and by a careful dissection the submaxillary lymphatic glands 
and the tongue removed. Regnoli advocated the removal of the tongue by a semilunar incision 
in the submaxillary triangle along the line of the lower jaw, and a vertical incision from the 
centre of the semilunar one backward to the hyoid bone. Care must be taken not to carry the 
first incision too far backward, so as to wound the facial arteries. The tongue is thus reached 
through the floor of the mouth, pulled out through the external incision, and removed with the 
knife. The great objection to this operation is that all the muscles which raise the hyoid 
bone and larynx are divided, and that therefore the movements of deglutition and respiration are 
interfered with. 
Finally, where both sides of the floor of the mouth are involved in the disease, or where very 
free access is required on account of the extension backward of the disease to the pillars of the 
fauces and the tonsil, or where the lower jaw is involved, the operation recommended by Syme 
must be performed. This is done by an incision through the central line of the lip across the 
chin, and down as far as the hyoid bone. The lower jaw is sawed through at the symphysis, and 
the two halves of the bone forcibly separated from each other. The mucous membrane is Sepa- 
rated from the bone, and the Genio-hyo-glossi detached from the bone, and the Hyo-glossi 
divided. The tongue is then drawn forward and removed close to its attachment to the hyoid 
bone. Adjacent lymph glands can be removed, and if the bone is implicated in the dis- 
ease, it can also be removed by freeing it from the soft parts externally and internally, and 
making a second section with the saw beyond the diseased part. 
Formerly many surgeons before removing the tongue performed a preliminary tracheotomy: 
(1) to prevent blood entering the air-passages; and (2) to allow the patient to breathe through 
the tube and not inspire air which had passed over a sloughy wound, and which was loaded with 
septic organisms and likely to induce septic pneumonia. By operating with the patient in the 
Trendelenburg position, the blood is caused to flow away from the air-passages. By the judicious 
use of iodoform the evil mentioned secondly may be obviated, and the preliminary tracheotomy is 
now usually dispensed with. 
1095 
THE NOSE. 
The nose is the peripheral portion of the organ of smell {organon olfactus): by 
means of the peculiar properties of its nerves it protects the lungs from the inhala- 
tion of deleterious gases and assists the organ of taste in discriminating the prop- 
erties of food. The organ of smell consists of two parts; one external, the outer 
nose; the other internal, the nasal fossae. 1096 
77/ORGANS OF SPECIAL SENSE 
THE OUTER NOSE (NASUS EXTERNUS). 
The outer nose is the more anterior and prominent part of the organ of smell. 
Of a triangular form, it is directed downward, and projects from the centre of 
the face, immediately above the upper lip. Its summit or root (radix nasi) is 
connected directly with the forehead. Its inferior part or base (basis nasi) pre- 
sents two elliptical orifices, the nostrils or anterior nares (nares), separated from 
each other by an antero-posterior septum, the mobile septum or columna nasi 
(septum mobile nasi). The margins of the nostrils are provided with a number 
of stiff hairs or vibrissae, which arrest the passage of foreign substances carried 
with the current of air intended for respiration. The point (apex nasi) is the free 
extremity of the nose. The lateral surfaces of the nose form, by their union in 
the middle line, the dorsum (dorsum nasi), the direction of which varies considerably 
in different individuals. The portion of the dorsum over the nasal bones is the 
bridge. Each lateral surface terminates below in a rounded eminence, the wing 
or ala nasi, which, by its lower margin (margo nasi), forms the outer boundary 
of the corresponding nostril. Above the ala is a depression, the alar sulcus. 
Seen from below. 
Side view. 
Lower lateral cartilage. 
•Sesamoid cartilages. 
Figs. 705 and 706.-Cartilages of the nose 
Structure.-The nose is composed of a framework of bones and cartilages, the 
latter being slightly acted upon by certain muscles. It is covered externally by the 
integument, internally by mucous membrane, and is supplied with vessels and nerves. 
The Bony Framework.-The bony framework occupies the upper part of the 
organ; it consists of the nasal bones and the nasal processes of the superior maxillary 
bones (pp. 104 and 109). 
The Cartilaginous Framework {cartilagines nasi) (Figs. 705 and 706).-The car- 
tilaginous framework consists of five pieces, the two upper and the two lower 
lateral cartilages and the cartilage of the septum. 
The Upper Lateral Cartilage (cartilago nasi lateralis) of each side is situated below 
the free margin of the nasal bone. It is flattened and triangular in shape. Its ante- 
rior margin is thicker than the posterior, and continuous with the cartilage of the 
septum. Its posterior margin is attached to the nasal process of the superior 
maxillary and nasal bones. Its inferior margin is connected by fibrous tissue with 
the lower lateral cartilage; one surface is turned outward, the other inward toward 
the nasal cavity. THE OUTER NOSE 
1097 
The Lower Lateral Cartilage, the Cartilage of the Aperture or the Greater Alar Car- 
tilage (cartilago alaris major) of each side consists of two thin, flexible plates situated 
immediately below the preceding, and bent upon themselves in such a manner as 
to form the inner and outer walls of the orifice of the nostril. The portion which 
forms the inner wall (crus mediate), thicker than the rest, is loosely connected with 
the corresponding portion of the opposite cartilage, and forms a small part of the 
columna. Its inferior border, free, rounded, and projecting, forms, with the thick- 
ened integument and subjacent tissue and the corresponding parts of the opposite 
side, the mobile septum. The part of the cartilage which forms the outer wall (crus 
tat erale) is curved to correspond with the ala of the nose; it is oval and flattened, 
narrow behind, where it is connected with the nasal process of the superior maxilla 
by a tough fibrous membrane, in which are found three or four small cartilaginous 
plates, the sesamoid, accessory quadrate or lesser alar cartilages (cartilagines alares 
minores). Above, it is connected by fibrous tissue to the upper lateral cartilage 
and front part of the cartilage of the septum; below, it falls short of the margin 
of the nostril; the ala being formed by dense cellular tissue covered by skin. In 
front the lower lateral cartilages are separated by a notch which corresponds 
with the point of the nose. 
The Triangular Cartilage of the Septum (cartilago septi nasi) (Figs. 705 and 707) 
is somewhat quadrilateral in form, thicker at its margins than at its centre, and 
completes the separation between the 
nasal fossae in front. Its anterior 
margin, thickest above, is connected 
with the nasal bones, and is continuous 
with the anterior margins of the two 
upper lateral cartilages. Below, it is 
connected to the inner portions of the 
lower lateral cartilages by fibrous 
tissue. Its posterior margin is con- 
nected with the perpendicular lamella 
of the ethmoid; its inferior margin with 
the vomer and the palate processes of 
the superior maxillary bones (Fig. 103). 
It may be prolonged backward 
(especially in children) for some dis- 
tance between the vomer and perpen- 
dicular plate of the ethmoid, forming 
what is termed the sphenoidal process 
(processus sphenoidalis septi cartilaginei). The septal cartilage does not reach 
as far as the lowest part of the nasal septum. This is formed by the inner 
portions of the lower lateral cartilages and by the skin; it is freely movable, and 
hence is termed the mobile septum (septum mobile nasi). 
Along the lower margin of the anterior half of the cartilage of the septum is 
another cartilage which is attached to the vomer and is known as the vomerine 
cartilage or cartilage of Jacobson (cartilago vomeronasalis). 
These various cartilages are connected to each other and to the bones by a tough 
fibrous membrane, which allows the utmost facility of movement between them. 
The Muscles of the Nose.-The muscles of the nose are situated beneath the 
integument; they are (on each side) the Pyramidalis nasi, the Levator labii supe- 
riores alaeque nasi, the Dilatator naris, anterior and posterior, the Compressor 
nasi, the Compressor narium minor, and the Depressor alae nasi. They have been 
previously described (p. 375). 
The Integument covering the dorsum and sides of the nose is thin, and loosely 
connected with the subjacent parts; but the integument of the tip and the alae of 
Fig. 707.-Bones and cartilages of septum of the nose. 
Right side. 1098 
THE ORGANS OF SPECIAL SENSE 
the nose is thicker and more firmly adherent, and is furnished with a large number 
of sebaceous follicles, the orifices of which are usually very distinct. 
The Mucous Membrane lining the interior of the nose is continuous with the 
skin externally and with the mucous membrane which lines the nasal fossae within. 
The Arteries of the Outer Nose.-The arteries of the nose are the lateralis nasi from 
the facial, and the inferior artery of the septum from the superior coronary, which 
supply the alae and septum, the sides and dorsum being supplied from the nasal 
branch of the ophthalmic and the infraorbital. 
The Veins of the Outer Nose.-The veins of the nose terminate in the facial and 
ophthalmic. 
The Lymphatics of the Outer Nose.-These vessels are shown in Figs. 487, 489, 
and 490. They empty chiefly into the submaxillary lymph glands. 
The Nerves of the Outer Nose.-The nerves for the muscles of the nose are derived 
from the facial, while the skin receives its branches from the infraorbital, infra- 
trochlear, and nasal branches of the ophthalmic. 
THE NASAL FOSSAE (CAVUM NASI). 
The nasal fossae are two irregular cavities situated in the middle of the face, 
one on each side of the middle line, and extending from before backward. They 
open in front, when the soft parts are in place, by the two nostrils or anterior nares, 
and terminate, behind, in the naso-pharynx by the posterior nares. 
Fig. 708.-External wall of right nasal fossa, parts of the turbinates having been cut away to show the 
orifices of the sinuses which open into the meatuses. CTestut.) 
The Anterior Nares (nares).-The anterior nares are somewhat pear-shaped 
apertures, each measuring about one inch antero-posteriorly and half an inch 
transversely at their widest part. The nasal fossae in the dry skull open in front 
by the anterior nasal aperture (apertura pyriformis). 
The Posterior Nares (choanae).-The posterior nares are two oval openings, 
which are smaller in the living or recent subject than in the skeleton, because they THE NASAL FOSSAE 
1099 
are narrowed by the mucous membrane. Each measures an inch in the vertical 
and half an inch in the transverse direction in a well-developed adult skull. 
For the description of the bony boundaries of the nasal fossae see section on 
Osteology (p. 143). 
Inside the aperture of the nostril is a slight dilatation, the vestibule (vestibulum 
nasi), which extends as a small pouch, the ventricle, toward the point of the nose. 
Above and behind the vestibule is surrounded by a prominence (limen nasi). 
Below the prominence the vestibule is lined with skin; above and behind it the 
fossa is lined with mucous membrane. The fossa, above and behind the vestibule, 
has been divided into two parts: an olfactory portion (regio oljactoria), a slit-like 
cavity, comprising the upper and central part of the septum and probably the 
superior turbinated bone, and a respiratory portion (regio respiratoria), which com- 
prises the rest of the fossa. 
Hiatus 
semilunaris 
Ant. ethm. 
cells 
■Eye-ball 
Groove (hiatus semilunaris) 
. leading to infundibulum 
.Middle turbinated bone 
Middle meatus 
•Antrum of Highmore 
.Inferior meatus 
•Inferior turbinated bone 
r Buccal cavity 
j Space between cheek and gum 
Molar tooth, upper jaw 
•Hoot of molar tooth 
1 Inferior dental nerve 
Hard palate 
Tongue 
Septum 
nasi 
Fig. 709.-Transverse vertical section of the nasal fossae. The section is made anterior to the superior 
turbinated bones. (Cryer.) 
Outer Wall (Figs. 708, 709).-The superior, middle, and inferior meatus (meatus 
nasi superior, medius and inferior) are described on pages 144 and 145. The 
sphenoidal air sinus opens into the spheno-ethmoidal recess (recessus sphenoethmoid- 
al is), a narrow recess above the superior turbinated bone (Fig. 708). The posterior 
ethmoidal cells open into the front and upper part of the superior meatus (Fig. 708). 
On raising or cutting away the middle turbinated bone the outer wall of the middle 
meatus is fully exposed (Figs. 708 and 709) and presents (1) a rounded elevation, 
termed the bulla ethmoidalis, opening on or immediately above which are the orifices 
of the middle ethmoidal cells; (2) a deep, narrow, curved groove, in front of the bulla 
ethmoidalis, termed the hiatus semilunaris, into which the anterior ethmoidal cells THE ORGANS OF SPECIAL SENSE 
1100 
and the antrum of Highmore (sinus maxillaris) open, the orifice of the latter being 
placed near the level of its roof. The middle meatus is prolonged, above and in 
front, into the infundibulum (infundibulum ethmoidale), which leads into the frontal 
sinus. The anterior extremity of the meatus is continued into a depressed area 
which lies above the vestibule and is named the atrium (atrium meatus medii 
nasi). The nasal duct opens into the anterior part of the inferior meatus, the 
opening being frequently overlapped by a fold of mucous membrane, and from 
the orifice of the duct a groove leads downward and forward. 
The Inner Wall (Fig. 709).-The inner wall or septum is frequently more or less 
deflected from the mesial plane (Figs. 101 and 709), thus limiting the size of one 
fossa and increasing that of the other. Ridges or spurs of bone growing outward 
from the septum are also sometimes present. Immediately over the incisive 
foramen at the lower edge of the cartilage of the septum a depression, the naso- 
palatine recess (recessus nasopalatinus), may be seen. In the septum close to this 
recess a minute orifice may be discerned; it leads into a blind pouch, the rudi- 
mentary organ of Jacobson (organon vomeronasale), which is well developed in 
some of the lower animals, but is rudimentary in man. The organ is supported 
by a plate of cartilage, distinct from the cartilage of the septum, the cartilage of 
Jacobson (p. 1097). The cartilage of Jacobson is to the outer side of the lower 
edge of the cartilage of the septum. The diverticulum opens anteriorly near the 
floor of the nose and close hy Stenson's foramen. Just below the opening of 
the blind pouch is an elevation, the eminence of Jacobson. 
The Mucous Membrane (membrana mucosa nasi).-The mucous membrane lining 
the nasal fossae is called the pituitary, from the nature of its secretion; or Schneide- 
rian, from Schneider, the first anatomist who showed that the secretion proceeded 
from the mucous membrane, and not, as was formerly imagined, from the brain. 
It is intimately adherent to the periosteum or perichondrium, over which it lies. 
It is continuous externally with the skin through the anterior nares, and with the 
mucous membrane of the naso-pharynx through the posterior nares. From the 
nasal fossae its continuity may be traced with the conjunctiva through the nasal 
duct and lachrymal canals; with the lining membrane of the tympanum and mas- 
toid cells through the Eustachian tube; and with the frontal, ethmoidal, and 
sphenoidal sinuses, and the antrum of Highmore through the several openings in 
the meatuses. The mucous membrane is thickest and most vascular over the 
turbinated bones. It is also thick over the septum, but in the intervals between 
the spongy bones and on the floor of the nasal fossae it is very thin. Where it 
lines the various sinuses and the antrum of Highmore it is thin and pale. 
Owing to the great thickness of this membrane, the nasal fossae are much 
narrower, and the turbinated bones, especially the lower ones, appear larger and 
more prominent than in the skeleton. From the same circumstances also the 
various apertures communicating with the meatuses are considerably narrowed 
or completely closed. The vestibule is lined by modified skin, and contains hairs 
(vibrissae) which guard the entrance of the nostril. 
Structure of the Mucous Membrane (Fig. 710).-The epithelium covering the 
mucous membrane differs in its character according to the functions of the part of 
the nose in which it is found. In the respiratory portion of the nasal cavity the 
epithelium is columnar and ciliated. Interspersed among the columnar ciliated 
cells are goblet or mucin cells, while between their bases are found smaller pyra- 
midal cells. In this region, beneath the epithelium and its basement membrane, 
is a fibrous layer infiltrated with lymph-corpuscles, so as to form in many parts 
a diffuse adenoid tissue, which is particularly plentiful in children, and beneath 
this a nearly continuous layer of smaller and larger glands, some mucous and some 
serous, the ducts of which open upon the surface. In the respiratory portion of 
the mucous membrane there is an extensive anastomosing plexus of veins, which THE NASAL FOSSAE 
1101 
in some regions forms a distinct cavernous tissue {plexus cavernosus concharum). 
The cavernous tissue is particularly distinct over the inferior turbinated bones. 
In the olfactory region the mucous membrane is yellowish in color and the epi- 
thelial cells are columnar and non-ciliated; they are of two kinds, supporting cells 
and olfactory cells. 
The Supporting Cells contain oval nuclei, situated in the deeper parts of the cells; 
the free surface of each cell presents a sharp outline, and its deep extremity is 
prolonged into a process which runs inward, branching to communicate with 
similar processes from neighboring cells, so as to form a network in the deep part 
of the mucous membrane. Lying between these central processes of the support- 
ing cells are a large number of spindle-shaped cells, the olfactory cells, which con- 
sist of a large spherical nucleus surrounded by a small amount of granular proto- 
plasm, and possessing two processes, of which one runs outward between the 
columnar epithelial cells, and projects on the surface of the mucous membrane 
as a fine, hair-like process, the olfactory hair; the other or deep process runs inward, 
is frequently beaded like a nerve-fibre, and is believed by most observers to be in 
connection with one of the terminal filaments of the olfactory nerve. Beneath the 
Fig. 710.-Section of the olfactory mucous membrane: a, epithelium; b, glands of Bowman; c, nerve bundles. 
(Cadiat.) 
epithelium, extending through the thickness of the mucous membrane, is a layer 
of tubular, often branched, glands, the glands of Bowman {glandulae oljactoriae), 
identical in structure with serous glands. 
The Arteries of the Nasal Fossae.-The arteries of the nasal fossae are the anterior 
and posterior ethmoidal, from the ophthalmic, which supply the ethmoidal cells, 
frontal sinuses, and roof of the nose; the spheno-palatine, from the internal maxil- 
lary, which supplies the mucous membrane covering the spongy bones, the 
meatuses, and septum; the inferior artery of the septum, from the superior 
coronary of the facial; and the infraorbital and alveolar branches of the internal 
maxillary, which supply the lining membrane of the antrum. The ramifications 
of these vessels form a close, plexiform network, beneath and in the substance of 
the mucous membrane. 
The Veins of the Nasal Fossae.-The veins of the nasal fossae form a close, cav- 
ernous-like network beneath the mucous membrane. This cavernous appearance 
is especially well marked over the lower part of the septum and over the middle 
and inferior turbinated bones. Some of the veins pass, with those accompanying 
the spheno-palatine artery, through the spheno-palatine foramen; and others, 
through the alveolar branch, to join the facial vein; some accompany the eth- 1102 
THE ORGANS OF SPECIAL SENSE 
moidal arteries, and terminate in the ophthalmic vein; and, lastly, a few com- 
municate with the veins in the interior of the skull, through the foramina in the 
cribriform plate of the ethmoid bone, and the foramen caecum. 
The Lymphatics of the Nasal Fossae.-The lymphatics can be injected from the 
subdural and subarachnoid spaces, and form a plexus in the superficial portion of 
the mucous membrane. The lymph is drained partly into one or two glands which 
lie near the great cornu of the hyoid 
bone and partly into a gland situated in 
front of the axis. 
The Nerves of the Nasal Fossae (Fig. 
711). - The nerves are: the olfactory, 
the nasal branch of the ophthalmic, fila- 
ments from the anterior dental branch of 
the superior maxillary, the Vidian, the 
naso-palatine, descending anterior pala- 
tine, and nasal branches of Meckel's 
ganglion. The olfactory, the special 
nerve of the sense of smell, is distributed 
to the olfactory region, and has been 
already referred to (p. 1019). The nasal 
branch of the ophthalmic division of the 
fifth nerve distributes filaments to the 
forepart of the septum and outer wall 
of the nasal fossae. Filaments from the 
anterior dental branch of the superior maxillary supply the inferior meatus and 
inferior turbinated bone. The Vidian nerve supplies the upper and back part of 
the septum and superior spongy bone, and the upper anterior nasal branches 
from the spheno-palatine ganglion have a similar distribution. The naso-palatine 
nerve supplies the middle of the septum. The larger or anterior palatine nerve 
supplies the lower nasal branches to the middle and lower spongy bones. 
Fig. 711.-Nerves of septum of nose. Right side. 
Surgical Anatomy.-Instances of congenital deformity of the nose are occasionally met with, 
such as complete absence of the nose, an aperture only being present; or perfect development 
on one side, and suppression or malformation on the other; or there may be imperfect apposi- 
tion of the nasal bones, so that the nose presents a median cleft or furrow. Deformities which 
have been acquired are much more common, such as flattening of the nose (saddle nose), the result 
of syphilitic necrosis, imperfect development of the nasal bones in cases of congenital syphilis, or 
a lateral deviation of the nose the result of fracture. 
The skin over the alae and tip of the nose is thick and closely adherent to subjacent parts. 
Inflammation of this part is therefore very painful, on account of the tension. The skin is largely 
supplied with blood, and, the circulation here being terminal, vascular engorgement is liable to 
occur, especially in women at the menopause and in both sexes from disorders of digestion , exposure 
to cold, etc. The skin of the nose also contains a large number of sebaceous follicles, and these, as 
a result of intemperance, are apt to become affected, and the nose becomes reddened, congested, 
and irregularly swollen. To this condition the term grog-blossom is popularly applied. In some 
of these cases there is enormous hypertrophy of the skin and subcutaneous tissues, producing 
pendulous masses, termed lipomata nasi. Ordinary epithelioma and rodent ulcer may attack 
the nose, the latter being the more common of the two. Lupus and syphilitic ulceration fre- 
quently attack the nose, and may destroy the whole of the cartilaginous portion. In fact, lupus 
vulgaris begins more frequently on the ala of the nose than in any other situation. 
Cases of congenital occlusion of one or both nostrils, or adhesion between the ala and septum 
may occur, and may require immediate operation, since the obstruction much interferes with 
sucking. Bony closure of the posterior nares may also occur. 
To examine the nasal cavities, the head should be thrown back and the nose drawn upward, 
the parts being dilated by some form of speculum. They can also be examined with the little finger 
or a probe, and in this way foreign bodies detected. A still more extensive examination can be 
made by Roux's operation, which was introduced for the cure of ozana. This operation enables 
the surgeon to remove any dead bone which may be present in this disease. The cartilaginous 
framework of the nose is lifted up by an incision made inside the mouth, through the junction THE EYE 
1103 
of the upper lip with the bone; the septum nasi and the lateral cartilages are divided with strong 
scissors till the anterior nares are completely exposed. The posterior nares can be explored by 
the aid of reflected light from the mouth, by which the posterior nares can be illuminated. The 
examination is very difficult to carry out, and, as a rule, sufficient information regarding the 
presence of foreign bodies or tumors in the naso-pharynx can be obtained by the introduction 
of the finger behind the soft palate through the mouth. The septum of the nose may be dis- 
placed or deviate from the middle line: this may be the result of an injury or from some con- 
genital defect in its development; in the latter case the deviation usually occurs along the line 
of union of the vomer and mesethmoid, and rarely occurs before the seventh year. Sometimes 
the deviation may be so great that the septum may come in contact with the outer wall of the 
nasal fossa, and may even become adherent to it, thus producing complete obstruction. Per- 
foration of the septum is not an uncommon affection and may arise from several causes: syphilitic 
or tuberculous ulceration, blood-tumor or abscess of the septum, and especially in workmen 
exposed to the vapor of bichromate of potash, from the irritating and corrosive action of fumes. 
When small, the perforation may cause a peculiar wliistling sound during respiration. When 
large, it may lead to the falling in of the bridge of the nose. 
Epistaxis is a very common affection in children. It is rarely of much consequence, and will 
almost always subside, but in the more violent hemorrhages of later life it may be necessary 
to plug the posterior nares. In performing this operation it is desirable to remember the size 
of the posterior nares. A ready method of regulating the size of the plug to fit the opening 
is to make it of the same size as the terminal phalanx of the thumb of the patient to be oper- 
ated on. 
Nasal polypus is a very common disease, and presents itself in three forms: the gelatinous, 
the fibrous, and the malignant. The first is by far the most common. It grows from the mucous 
membrane of the outer wall of the nasal fossa, where there is an abundant layer of highly vas- 
cular submucous tissue; rarely from the septum, where the mucous membrane is closely adher- 
ent to the cartilage and bone, without the intervention of much, if any, submucous tissue. The 
most common seat of gelatinous polyps is probably the middle turbinated bone. The fibrous 
polypus generally grows from the base of the skull behind the posterior nares or from the roof 
of the nasal fossae. The malignant polypi, both sarcomatous and carcinomatous, may arise 
in the nasal cavities and the naso-pharynx; or they may originate in the antrum, and protrude 
through its inner wall into the nasal fossa. 
Rhinoliths or nose-stones may sometimes be found in the nasal cavities. They arise from 
the deposition of phosphate of lime upon either a foreign body or a piece of inspissated secretion. 
The nasal passages furnish a secretion of their own and receive secretion from other parts 
(tears and secretions of the accessory sinuses). The nasal cavities contain the ethmoidal laby- 
rinths, the lateral masses of the ethmoid (which form the superior and middle turbinated bones), 
and the inferior turbinated bones. The nasal cavity is surrounded by three pairs of pneumatic 
spaces, the accessory sinuses. These are the maxillary sinuses, the frontal sinuses, and the 
cells of the ethmoidal labyrinth. The lachrymal duct opens into the inferior meatus. Inflam- 
mation of the air-cells may follow inflammation of the nasal mucous membrane or bone disease. 
One set of cells or many may suffer. Suppuration may occur. Pus may be blocked up and 
retained. Dead bone may form. The most serious conditions may follow (abscess of brain,, 
sinus thrombosis, septicaemia), and an operation is necessary to obtain relief. 
THE EYE. 
The eyeball or globe (bulbus oculif (Figs. 712 and 716) is contained in the ante- 
rior part of the cavity of the orbit. In this situation it is securely protected from 
injury, whilst its position is such as to ensure the most extensive range of sight. 
It is acted upon by numerous muscles, by which it is capable of being directed 
to different parts; it is supplied by vessels and nerves, and is additionally pro- 
tected in front by the orbital margins, eyelids, etc. 
The eyeball is embedded in the fat of the orbit, but is partly surrounded by 
a thin membranous sac, the capsule of Tdnon, which isolates it, so as to allow 
of free movement. 
The Fascia or Capsule of T6non fascia bulbi [T enmity (Figs. 712 and 
713).-The fascia or capsule of Tenon consists of a thin membrane which 
envelops the eyeball from the optic nerve to the ciliary region, separating it from 
the orbital fat and forming a socket in which it plays. Its inner surface is smooth,, 
and is in contact with the outer surface of the sclerotic, the perisclerotic or supra- THE ORGANS OF SPECIAL SENSE 
1104 
scleral lymph-space only intervening. This lymph-space is continuous with the 
subdural and subarachnoid spaces, and is traversed by delicate bands of con- 
OPTIC NERVE 
-CORNEA 
UPPER 
' TARSUS 
CAPSULE 
OF TENON' 
LOWER 
TARSUS 
Fig. 712.-The right eye in sagittal section, showing the capsule of T6non (semidiagrammatic). (Testut.) 
nective tissue which extend between 
the capsule and the sclerotic. This 
lymph-space forms a flexible pocket, 
in which the globe rotates. The cap- 
sule of Tenon, with the globe, forms 
a ball-and-socket joint (Deaver). 
The capsule is perforated behind by 
the ciliary vessels and nerves and by 
the optic nerve, being continuous with 
the sheath of the latter. In front it 
blends with the ocular conjunctiva, 
and with it is attached to the ciliary 
region of the eyeball. It is perforated 
by the muscles which move the eye- 
ball and on to each muscle it sends 
a tubular sheath. The sheath of the 
Superior oblique is carried as far as 
the fibrous pulley of that muscle; that 
on the inferior oblique reaches as far 
as the floor of the orbit, to which it 
gives off a slip. The sheaths on the 
recti are gradually lost in the peri- 
mysium, but they give off important expansions. The expansion from the 
Superior rectus blends with the tendon of the Levator palpebrae; that of the 
Fig. 713-The capsule of T^non. The aponeurosis is 
seen from behind forward on the posterior hemisphere of 
the globe: a, cellulo-fibrous intermuscular laminae; b, deep 
leaf of the sheath incised at the point where it leaves the 
muscle to fold itself on the posterior hemisphere when 
it forms the posterior capsule; d, partly incised; c, serous 
membrane. (Poirier and Charpy.) THE EYE 
1105 
Inferior rectus is attached to the inferior tarsal plate. These two recti, therefore, 
will exercise some influence on the movements of the eyelids. The expansions 
from the sheaths of the Internal and External recti are strong, especially the one 
from the latter muscle, and are attached to the lachrymal and malar bones respec- 
tively. As they probably check the action of these two recti, they have been 
named the internal and external check ligaments. 
Lockwood has also described a thickening of the lower part of the capsule of 
Tenon, which* he has named the suspensory ligament of the eye. It is slung like a 
hammock below the eyeball, being expanded in the centre and narrow at its 
extremities, which are attached to the malar and lachrymal bones respectively.1 
The anterior one-third of the globe is covered by the conjunctiva, or mucous 
membrane, reflected from the inner surfaces of the lids (Fig. 715). A lateral view 
VISUAL 
AXIS 
OPTIC 
'AXIS 
POSTERIOR CHAMBER 
OF EYE 
OCULAR 
CONJUNCTIVA 
CILIARY 
PROCESS 
CILIARY 
MUSCLE 
ZONULE 
OF ZINN 
PARS CILIARIS 
RETINAE 
ORA SERRATA 
DIAMETER 
EQUATORIAL 
VITREOUS 
BODY 
PARS OPTICA 
RETINAE 
CHOROID 
SCLEROTIC 
OPTIC 
PAPILLA 
.YELLOW 
SPOT 
OPTIC' 
EXCAVATION 
EXTERNAL 
AXIS 
Fig. 714.-The right eye in horizontal section. (Toldt.) 
of the globe shows that it is composed of segments of two spheres of different sizes 
(Figs. 712, 714, 715, and 716). The anterior segment is one of a small sphere, and 
forms about one-sixth of the eyeball. It is more prominent than the posterior seg- 
ment, which is one of a much larger sphere, and forms about five-sixths of the globe. 
The segment of the larger sphere is opaque, and formed by the sclerotic, the tunic 
of protection to the eyeball; the smaller sphere is transparent, and formed by the 
cornea. Between the small, anterior or corneal segment, and the large, posterior 
or scleral segment, is a shallow and narrow groove, the scleral sulcus (sulcus sclerae}. 
The anterior pole is the centre of the anterior portion of the cornea. The posterior 
pole is the centre of the posterior portion of the sclerotic. A straight line joining 
1 See a paper by C. B. Lockwood, Journal of Anatomy and Physiology, vol. xx., part i. p. 1.-Ed. of 15th 
English edition. 1106 
THE ORGANS OF SPECIAL SENSE 
these two poles is the sagittal or optic axis {axis optica} (Fig. 714). A line drawn 
around the eyeball equally distant at all points from the two poles is called the 
equatorial diameter or the equator (Fig. 714). The plane of the equator divides 
the globe in an anterior and a posterior hemisphere. Meridians may be drawn from 
one pole to the other at right angles to the equator. The visual axis {linea visits} 
(Fig. 714) passes in a straight line from the first nodal point on the cornea to the 
fovea centralis of the yellow spot on the retina. A nodal point is the point of inter- 
section of convergent rays with the visual axis. The first nodal point is 6.9685 mm. 
ANTERIOR 
CHAMBER 
POSTERIOR CHAMBER 
LENS 
VITREOUS 
VITREOUS 
-CHOROID 
Fig. 715.-Diagram of a horizontal section of the right eye, showing the upper surface of the lower 
segment. (Testut.) 
behind the summit of the cornea. The axes of the eyeballs are nearly parallel, 
and therefore do not correspond to the axes of the orbits, which are directed 
outward. The optic nerves follow the direction of the axes of the orbits, and 
are therefore not parallel; each nerve enters its eyeball about 1 mm. below and 
3 mm. to the inner or nasal side of the posterior pole (Fig. 714). The eyeball 
measures rather more in its transverse and antero-posteror diameters than in its 
vertical diameter, the former amounting to nearly an inch, the latter to about 
nine-tenths of an inch. The diameters in the female are somewhat less than 
in the male. 
The eyeball is composed of three investing tunics and of three refracting media. THE SCLERA 
1107 
THE TUNICS OF THE EYE. 
From without inward the three tunics are: 
I. Sclerotic Coat and Cornea. 
II. Choroid, Ciliary Body, and Iris. 
III. Retina. 
I. The Fibrous or External Coat: The Sclerotic and Cornea 
(Tunica Fibrosa Oculi). 
The sclerotic and cornea (Figs. 714, 715, and 716) form the external tunic of 
the eyeball; they are essentially fibrous in structure, the sclerotic being opaque, 
and forming the posterior five-sixths of the globe; the cornea, which forms the 
remaining sixth, being transparent. 
The Sclera or Sclerotic Coat (axtypo^, hard).-The sclera or sclerotic coat 
has received its name from its extreme density and hardness; it is a firm, unyield- 
ing, opaque, fibrous membrane, forming the posterior five-sixths of the outer coat 
Cornea 
Anterior chamber. 
Canal of Schlemm. 
Ciliary 
body. 
Posterior 
chamber.' 
Ciliary 
processes. 
Crystalline lens. 
Canal of 
Petit. 
Cavity occupied 
by vitreous humor. 
Internal 
rectus 
muscle. 
Retina. 
Choroid 
coat. 
Canal for 
central artery. 
Sclerotic coat. 
Nerve sheath. 
-Optic nerve. 
Fig. 716.-A horizontal section of the eyeball. (Allen.) 
and serving to maintain the form of the globe. It is much thicker behind than in 
front. Its external surface is of a white color, and is in contact with the inner 
surface of the capsule of Tenon, a lymph-space intervening; it is quite smooth, 
except one-quarter of an inch back of the sclero-corneal junction, at the points 
where the Recti and Obliqui muscles are inserted into it, and its anterior part is 
covered by the conjunctival membrane (Fig. 744); hence the whiteness and bril- 
liancy of the front of the eyeball. Its inner surface is stained a brown color, marked 
by grooves, in which are lodged the ciliary nerves and vessels (Figs. 719, 724, and 
725); the inner surface of the sclera is loosely connected by three layers of exceed- 1108 
THE ORGANS OF SPECIAL SENSE 
ingly fine cellular pigmented tissue (lamina jusca) with the outer surface of the 
choroid, an extensive lymph-space, the perichoroidal space (spatium perichorioideale) 
(Figs. 727and 744) intervening between the sclerotic and choroid. Behind the sclera 
is pierced by the optic nerve (n. opticus), and is continuous with the fibrous sheath 
of the nerve, which is derived from the dura mater (Fig. 721). At the point where 
the optic nerve passes through the sclerotic, the lamina fusca is represented by an 
arrangement of the fibrous tissue which forms a thin network, the cribriform lamina 
(lamina cribrosa sclerae) (Fig. 731); the minute orifices in this network serve for the 
transmission of separate bundles of nervous filaments, and the fibrous septa divid- 
ing them from one another are continuous with the membranous processes which 
separate the bundles of nerve-fibres. One of these openings (porus opticus), larger 
than the rest, occupies the centre of the lamella; it transmits the arteria centralis 
retinae to the interior of the eyeball (Fig. 731). Around the cribriform lamella are 
numerous small apertures for the transmission of the ciliary nerves and the short 
ciliary arteries, and about midway between the margin of the cornea and the entrance 
of the optic nerve are four or five large apertures, for the transmission of veins (venae 
vorticosae) (Fig. 721). In front, the fibrous tissue of the sclerotic is continuous with 
the substantia proporia, the cornea by direct continuity of tissue (Fig. 744), but the 
opaque sclerotic slightly overlaps the outer surface of the transparent cornea. In 
the depths of the line of junction between the cornea and the sclera there is a circular 
canal, the canal of Schlemm (sinus venosus sclerae) (Figs. 716, 723, 727, and 744). 
This canal receives the sclera veins (Fig. 723) and communicates internally by num- 
erous minute openings in the pectineal ligament of the iris (Fig. 744) with the ante- 
rior chamber of the eyeball. These openings are the spaces of Fontana (Fig. 727). 
Structure.-The sclerotic is formed of white fibrous tissue intermixed with fine 
elastic fibres, and of flattened connective-tissue corpuscles, some of which are pig- 
mented, contained in cell-spaces between the fibres (Figs. 720 and 731). These 
fibres are aggregated into bundles, some of which are arranged in layers having an 
equatorial direction, but most of which are arranged in layers lying in meridian lines. 
Thesclera is joined to the choroid by three thin layers of loose connective tissue con- 
taining pigment cells, the lamina fusca (lamina jasciae sclerae) (Fig. 724). Where 
the optic nerve passes through the sclera there is very thin network to represent the 
lamina fusca. This network is the lamina cribrosa (Fig. 731). The muscles of 
the eyeball are attached to the sclera (Figs. 715, 716, and 744), and their tendons 
enter among the bundles of fibrous connective tissue. The conjunctiva covers the 
anterior portion of the sclera and is attached to it by submucous tissue (Figs. 715 
and 727). The sclera yields gelatin on boiling. Its vessels (Figs. 721 and 723) are not 
numerous, the capillaries being of small size and uniting at long and wide intervals. 
It obtains arterial blood from the short posterior ciliary and the anterior ciliary 
arteries. The venous blood is removed by the venae vorticosae and the anterior ciliary 
veins. There are lymph-spaces between the cells which empty into the periscleral 
(Fig. 712 and p. 1104) and perichoroidal lymph-spaces (Fig. 727). Its nerves are 
derived from the ciliary nerves (Fig. 719). They lose their medullary sheaths and 
enter among the bundles of fibrous tissue, but it is not known how they terminate. 
The Cornea (Figs. 712, 715, and 721).-The cornea is the projecting transparent 
part of the external tunic of the eyeball, and forms the anterior sixth of the globe. It 
is almost, but not quite, circular in shape, occasionally a little broader in the transverse 
than in the vertical direction. It is convex anteriorly, and projects forward from 
the sclerotic in the same manner that a watch-glass does from the case. Its degree 
of curvature varies in different individuals, and in the same individual at different 
periods of life, it being more prominent in youth than in advanced life, when it 
becomes flattened. Usually the curvature is slightly greater in the vertical plane 
than in the horizontal plane; at its centre than at its periphery, and at its temporal 
than at its nasal side. The cornea is dense and of uniform thickness throughout; 
© 7 THE CORNEA 
1109 
its posterior surface is perfectly circular in outline, and exceeds the anterior sur- 
face slightly in extent, from the latter being overlapped by the sclerotic. The 
anterior surface is covered with conjunctiva (Fig. 727). 
Structure (Fig. 717).-The cornea consists of five layers-namely: (1) the anterior 
or epithelial layer; (2) the anterior elastic layer; (3) the substantia propria; (4) 
the posterior elastic layer; (5) the posterior or endothelial layer. 
Anterior 
epithelium 
.Anterior 
elastic 
membrane 
Substantia 
propria 
Posterior 
elastic 
.membrane 
•Posterior 
epithelium 
Fig. 717.-Vertical section through the cornea of a newborn child. X 200. (Szymonowicz.) 
(1) The Anterior Layer (epithelium corneae) is composed of stratified epithelium 
and is continuous with the cells of the conjunctiva at the borders of the cornea. 
There are from five to eight strata of nucleated cells in the anterior layer. The 
deepest cells are columnar. Above the columnar cells are several layers of 
polygonal cells, most of which have finger-like processes and are called prickle 
cells. At the surface the cells and nuclei become flat. The anterior epithelial 
layer prevents the absorption of the fluid of the tears. 
(2) The Anterior Elastic or Anterior Limiting Layer or Bowman's Membrane (lamina 
elastica anterior) is less than half the thickness of the layer of stratified epithelium. THE ORGANS OF SPECIAL SENSE 
1110 
It differs in some essential respects from true elastic tissue. It shows evidences 
of fibrillary structure, and does not have a tendency to curl inward or to undergo 
fracture when detached from the other layers of the cornea. It consists of ex- 
tremely close interwoven fibrils, similar to those found in the rest of the cornea 
proper, but contains no corneal corpuscles. It ought, therefore, to be regarded 
as a part of the proper tissue of the cornea, 
(3) The Substantia Propria or proper substance of the cornea forms the main 
thickness of that structure. It is fibrous, tough, unyielding, perfectly transparent, 
and continuous with the sclerotic. It is composed of about sixty flattened lamellae, 
superimposed one on another. These lamellae are made up of bundles of modified 
connective tissue, the fibres of which are directly continuous with the fibres of the 
sclerotic. The fibres of each lamella are for the most part parallel with each 
other; those of alternating lamellae at right angles to each other. Fibres, however, 
frequently pass obliquely from one lamella to the next (fibrae arcuatae). 
The lamellae are connected with each other by an interstitial cement-substance, 
in which are spaces, the corneal spaces, cell spaces or lacunae (Fig. 718). The 
spaces are stellate in shape, and have numerous offsets or canaliculi (Fig. 718), 
by which they communicate with each other. Each space contains a cell, the 
corneal corpuscle (Fig. 718), which resembles in form the space in which it is 
Corneal cell in 
lymph space 
Lymph canaliculi 
Fig. 718.-From a horizontal section of an ox's cornea. Positive picture of the canal system demonstrated 
by the gold chloride method. X 450. (Szymonowicz.) 
lodged, but it does not entirely fill it, the remainder of the space containing 
lymph. In the aged the margin of the cornea becomes opaque gray. This rim 
is called the arcus senilis, and is due to fat deposit in the lamellae and corneal 
corpuscles. 
(4) The Posterior Elastic Lamina, the Membrane of Descemet, or the Membrane 
of Demours (lamina elastica posterior), which covers the proper structure of the 
cornea behind, presents no structure recognizable under the microscope. It 
consists of an elastic, and perfectly transparent homogeneous membrane, of 
extreme thinness, which is not rendered opaque by either water, alcohol, or acids. 
It is very brittle, but its most remarkable property is its extreme elasticity, and 
the tendency which it presents to curl up, or roll upon itself, with the attached 
surface innermost, when separated from the proper substance of the cornea. Its 
use appears to be (as suggested by Dr. Jacob) "to preserve the requisite perma- 
nent correct curvature of the flaccid cornea proper." 
At the margin of the cornea this posterior elastic membrane breaks up into fibres 
to form a reticular structure at the outer angle of the anterior chamber, the intervals 
between the fibres forming small cavernous spaces, the spaces of Fontana (spatia THE CHOROID 
1111 
anguli iridis) (Fig. 727). These little recesses communicate with a circular canal 
in the deeper parts of the corneo-scleral junction. This is the canal of Schlemm 
(sinus venosus sclerae) (Figs. 716, 723, and 727); it communicates internally with 
the anterior chamber through the spaces of Fontana, and externally with the 
scleral veins. Some of the fibres of this reticulated structure are continued into 
the front of the iris, forming the ligamentum pectinatum iridis; while others are 
connected with the forepart of the sclerotic and choroid. 
(5) The Posterior Layer or the Corneal Endothelium (endothelium camerae ante- 
rioris) lines the aqueous chamber and prevents the absorption of the aqueous 
humor. It covers the posterior surface of the elastic lamina, is reflected on to 
the front of the iris, and also lines the spaces of Fontana. It consists of a single 
layer of polygonal flattened transparent nucleated cells, similar to those lining 
other serous cavities. 
Arteries and Nerves.-The foetal cornea contains blood-vessels which pass from 
the margin almost to the centre. The adult cornea contains no blood-vessels, 
except at its margin. The capillaries from the sclera and conjunctiva form loops 
at the corneal margin, and many of these loops enter the cornea for a distance of 
1 mm. (Fig. 723). The balance of the cornea is non-vascular and obtains its 
nourishment from the lymph in the lacunae and canaliculi. Lymphatic vessels 
have not as yet been demonstrated in it, but are represented by the channels in 
which the bundles of nerves run; these channels are lined by endothelium and are 
continuous with the cell-spaces. The nerves are numerous, twenty-four to thirty- 
six in number (Kolliker), forty to forty-five (Waldeyer and Sumisch); they are 
derived from the ciliary nerves; they form the annular plexus (plexus annularis), 
at the corneal margin, and enter the laminated tissue of the cornea, lose their 
medullary sheaths, and ramify throughout the substantia propria as the funda- 
mental plexus or the plexus of the stroma. From this deep plexus come perforating 
fibres (fibrae perforantes), which pass through the anterior elastic lamina and form 
the subepithelial plexus, and from it fibrils are given off which ramify between 
the epithelial cells, forming a network which is termed the intra-epithelial plexus. 
Nerve-fibres from the annular plexus and from the plexus of the stroma come 
into close relation with the corneal corpuscles. 
Dissection.-In order to separate the sclerotic and cornea, so as to expose the second tunic, 
the eyeball should be immersed in a small vessel of water and held between the finger and thumb. 
The sclerotic is then carefully incised, in the equator of the globe, till the choroid is exposed. 
One blade of a pair of probe-pointed scissors is now introduced through the opening thus made, 
and the sclerotic divided around its entire circumference, and removed in separate portions. 
The front segment being then drawn forward, the handle of the scalpel should be pressed gently 
against it at its connection with the iris, and, these being separated, a quantity of perfectly trans- 
parent fluid will escape; this is the aqueous humor. In the course of the dissection the ciliary 
nerves (Fig. 719) may be seen lying in the loose cellular tissue between the choroid and sclerotic 
or continued in delicate grooves on the inner surface of the latter membrane. 
II. The Choroid, Ciliary Body, and Iris, the Tunica Media, the Uveal Tract 
(Tunica Vasculosa Oculi) (Figs. 714, 716, 719, 724, 744). 
The second or middle tunic of the eye is formed from behind forward by the 
choroid, the ciliary body, and the iris. 
The choroid is the vascular and pigmentary tunic of the eyeball, investing the 
posterior five-sixths of the globe, and extending as far forward as the ora serrata 
of the retina; the ciliary body connects the choroid to the circumference of the 
iris. The iris is the circular muscular septum, which hangs vertically behind the 
cornea, presenting in its centre a large rounded aperture, the pupil. 
The Choroid (chorioidea).-The choroid is a thin, highly vascular membrane, 
of a dark-brown or chocolate color, which invests the posterior five-sixths of the 1112 
THE ORGANS OF SPECIAL SENSE 
globe, and is pierced behind by the optic nerve, and in this situation is firmly 
adherent to the sclerotic. It is thicker behind than in front. Externally, it is 
loosely connected by the lamina 
fusca with the inner surface of the 
sclerotic (p. 1108). Its inner sur- 
face is attached to the retina. 
Structure (Fig. 720).-The choroid 
consists of a dense capillary plexus 
and of small arteries and veins, 
carrying the blood to and returning 
it from this plexus (Fig. 723), and of 
branched and pigmented cells which 
lie in connective tissue. There -are 
three layers in the choroid. Named 
from without inward, they are the 
lamina suprachorioidea, the choroid 
proper, and lamina basalis (Fig. 720). 
(1) The Lamina Suprachorioidea 
is on the external surface, that is, 
the surface next to the sclerotic. 
It resembles the lamina fusca of 
the sclerotic. It is composed of 
delicate non-vascular lamellae, each 
lamella consisting of a network of 
fine elastic fibres, among which are 
branched pigment-cells. The spaces 
between the lamellae are lined by 
endothelium, and open freely into the perichoroidal lymph-space, which, in its 
turn, communicates with the periscleral space by the perforations in the sclerotic 
through which the vessels and nerves are transmitted. 
(2) The Choroid Proper is internal to the lamina suprachorioidea. In consequence 
of the small arteries and veins of the choroid proper being arranged on the outer 
surface of the capillary network, it is customary to describe this as consisting of 
two layers: the outermost (lamina vasculosa), composed of small arteries and 
Fig. 719.-The choroid and iris. (Enlarged.) 
Pigment layer 
of retina 
Lamina 
basalis 
Lamina 
ehorio- 
capillaris 
Lamina 
vasculosa 
Lamina supra- 
chor ioidea 
Part of the 
sclera 
Fig. 720.-Vertical section through the chorioidea and a part of the sclera of an ape. X 440. (Szymonowicz.) 
veins, with pigment-cells interspersed between them, and the inner (lamina 
char iocapillar is), consisting of a capillary plexus. The external layer of the choroid 
proper or the lamina vasculosa consists, in part, of the larger branches of the short THE CHOROID 
1113 
posterior ciliary arteries (Figs. 721, 723, and 725), which run forward between the 
veins, before they bend inward to terminate in the capillaries; but this layer is 
corner 
.IRIS 
ANTERIOR 
CILIARY 
. ARTERY 
MusC1.e 
SCLEROTIC 
VENA 
VORTICOSA 
Ciliary 
NERve 
OPTIC 
NERVE 
SHORT 
POSTERIOR 
CILIARY 
ARTERIES 
LONG POSTERIOR 
CILIARY ARTERY 
Fig. 721.-Vessels and nerves of the choroid and iris, seen from above. The sclerotic and cornea have 
been largely removed. (Testut.) 
formed principally of veins, which have a whirl-like arrangement and empty into 
four or five large equidistant trunks, the venae vorticosae (Figs. 721, 722, and 723), 
which pierce the sclerotic midway 
between the margin of the cornea 
and the entrance of the optic 
nerve. Around the veins are 
lymph-spaces. Interspersed be- 
tween the vessels are dark star- 
shaped pigment-cells, the offsets 
from which, communicating with 
similar branchings from neigh- 
boring cells, form a delicate net- 
work or stroma, which toward 
the inner surface of the choroid 
loses its pigmentary chraacter. 
The internal layer of the choroid 
proper consists of an exceedingly 
fine capillary plexus, formed by 
the short ciliary vessels(Fig.723), 
and is known as the tunic of 
Ruysch (lamina choriocapillaris). 
The network is close, and finer at the hinder part of the choroid than in front. 
About half an inch behind the cornea its meshes become larger, and are continuous 
Fig. 722.--The veins of the choroid. (Enlarged.) 1114 
THE ORGANS OF SPECIAL SENSE 
with those of the ciliary processes. These two laminae are connected by an interme- 
diate stratum, which is destitute of pigment-cells and consists of fine elastic fibres. 
On the inner surface of the lamina choriocapillaris is a very thin, structureless, 
or, according to Kolliker, faintly fibrous membrane, called the lamina basalis 
or membrane of Bruch; it is closely connected with the stroma of the choroid, and 
separates it from the pigmentary layer of the retina. 
* b f fi 
Cornea 
Pl c 
4 3 2 
Iris- 
a 
ai 
Lens. 
Proc, ciliar. 
Ora serrata. 
di 
d 
Retina/- 
Chorioidea' 
Sclera- 
III 
s 
III 
II 
>1 
II 
■I 
As 
■MM 
Ts 
Fig. 723.-Diagram of the blood-vessels of the eye, as seen in a horizontal section. (Leber, after Stohr.) 
Course of vasa centralia retinae: a, arteria, «i vena centralis retinae; ft, anastomosis with vessels of outer 
coats; 7, anastomosis with branches of short posterior ciliary arteries; d, anastomosis with chorioideal vessels. 
Course of vasa ciliar, postic. brev.: I, arteriae, and Ij, venae ciliar, postic. brev.; II, episcleral artery; 
Hi, episcleral vein; III, capillaries of lamina choriocapillaris. 
Course of vasa ciliar, postic. long.: 1, a. ciliar. post, longa; 2, circulus iridis major cut across; 3, branches to 
ciliary body; 4, branches to iris. . 
Course of vasa ciliar, ant.: a, arteria, alt vena ciliar, ant.; b, junction with the circulus iridis major; C, junc- 
tion with lamina choriocapill.; d, arterial, and di, venous episcleral branches; e, arterial, and Ci, venous branches 
to conjunctiva sclerae; /, arterial, and/i, venous branches to corneal border; V, vena vorticosa; S, transverse 
section of sinus venosus sclerae. 
Tapetum (tucidum).-This name is applied to the iridescent appearance which 
is seen in the outer and posterior parts of the choroid of many animals, but not 
in man. 
The ciliary body should now be examined. It may be exposed, either by detaching the iris 
from its connection with the Ciliary muscle, or by making a transverse section of the globe, and 
examining it from behind. THE CILIARY BODY 
1115 
The Ciliary Body {corpus cihare) (Fig. 716).- Ihe ciliary body or cyclon joins 
the choroid to the margin of the iris. It is in reality a process of the choroid 
or uveal tract and comprises the orbiculus ciliaris, the ciliary processes, and the 
Ciliary muscle. 
The Orbiculus Ciliaris or Annulus Ciliaris (Figs. 724, 726, and 742).-The 
orbiculus ciliaris is a zone of about one-sixth of an inch in width, directly con- 
tinuous with the anterior part of the choroid. The lamina basalis presents 
numerous ridges arranged in a radial manner. The depressions between the 
ridges are filled with retinal pigment epithelium (Szymonowicz). The orbiculus 
contains no lamina choriocapillaris. 
The Ciliary Processes {processus ciliares) (Figs. 714, 716, 726, and 744).-The 
ciliary processes are formed by the plaiting and folding inward of the various 
layers of the choroid-t. e., the choroid proper and the lamina basalis-at its 
anterior margin, and are received between corresponding foldings of the suspen- 
sory ligament of the lens, thus establishing a connection between the choroid and 
inner tunic of the eye. They are arranged in a circle, and form a sort of plaited 
frill, the corona ciliaris, behind the iris, 
round the margin of the lens (Figs. 726 
and 744). They vary between sixty and 
eighty in number, lie side by side, and 
may be divided into large and small; 
the latter, consisting of about one-third 
of the entire number, are situated in the 
spaces between the former, but without 
regular alternation. The larger processes 
are each about one-tenth of an inch in 
length, and are attached by their per- 
iphery to three or four of the ridges of 
the orbiculus ciliaris, and are continu- 
ous with the layers of the choroid; the 
opposite margin is free, and rests upon 
the circumference of the lens. Their 
anterior surface is turned toward the 
back of the iris, with the circumference of which they are continuous. The 
posterior surface is connected with the suspensory ligament of the lens. 
Structure.-The ciliary processes are similar in structure to the choroid, but the 
vessels are larger, and have chiefly a longitudinal direction. They are the most 
vascular portion of the eyeball. The processes are covered on their inner surface 
by two strata of black pigment-cells, which are continued forward from the retina, 
and are named the pars ciliaris retinae (Figs. 720 and 727). In the stroma of the 
ciliary processes there are also stellate pigment-cells, which, however, are not so 
numerous as in the choroid itself. 
The Ciliary Muscle or Bowman's Muscle (m. ciliaris') (Figs. 719, 721, 725, 
727, 728, and 729).-The ciliary muscle consists of unstriped fibres; it forms 
a grayish, semitransparent, circular band, about one-eighth of an inch broad, 
on the outer surface of the forepart of the choroid, between the choroid and 
the iris and back of the sclero-corneal junction. It is thickest in front and 
gradually becomes thinner behind. It consists of two sets of fibres, radiating and 
circular. 
The Radiating Fibres (fibrae meridianales [Bruckei]) (Figs. 727 and 744), much 
the more numerous, arise at the point of junction of the cornea and sclerotic, and 
partly also from the ligamentum pectinatum iridis, and, passing backward, are 
attached to the choroid opposite to the ciliary processes. One bundle, according 
to Waldeyer, is continued backward to be inserted into the sclerotic. 
PUPIL 
IRISx 
ANNULUS 
.CILIARIS 
CILIARY 
MARGIN- 
OF IRIS 
,ORBICULUS 
CILIARIS 
POSTERIOR 
SMOOTH 
PORTION 
OF CHOROID 
INNER 
SURFACE' 
OF SCLERA 
^CILIARY 
NERVES 
CORNEA (POS-_ 
terior surface) 
Fig. 724.-The middle or vascular coat of the eyeball 
exposed from without. Left eye, seen obliquely from 
above and before. (Toldt.) 1116 
THE ORGANS OF SPECIAL SENSE 
The Circular Fibres (fibrae circulates [Mulleri]) (Figs. 727 and 744) are internal to 
the radiating ones and to some extent unconnected with them, and have a circular 
coursearound the attachment of the iris. They are sometimes called the "ring 
muscle" of Muller, and were formerly described as the ciliary ligament. They are 
well developed in hypermetropic, but are rudimentary or absent in myopic eyes. 
■Anterior ciliary artery. 
Short ciliary arteries. 
Anterior ciliary artery. 
Fig. 725.-The arteries of the choroid and iris. The sclerotic has been mostly removed. (Enlarged.) 
The Ciliary muscle is admitted to be the chief agent in accommodation-i. e., in 
adjusting the eye to the vision of near objects. Bowman believed that this was 
effected by its compressing the vitreous body, and so causing the lens to advance. 
At the present time all agree that the chief element in accommodation is altered 
curvature of the lens, but there is diversity of opinion as to the manner in which 
ORBICULARIS 
CHIARIS 
CILIARY 
FOLDS 
.CILIARY 
BODY 
iris (poste- 
rior surface) 
.CILIARY 
PROCESSES 
.EQUATOR 
OF LENS 
Fig. 726.-A portion of the corona ciliaris magnified. The ciliary processes and the ciliary folds. (Toldt.) 
this is accomplished. The view which now prevails is that of Helmholtz. He 
maintained that in an unaccommodated eye the capsule and suspensory ligament 
of the lens are tense, and their pressure flattens the anterior surface of the lens, 
and parallel rays (and rays from objects far off are practically parallel) "are 
focused on the retina without any sense of effort."1 
"In accommodation for a near object the meridional or antero-posterior fibres 
1 Stewart, Manual of Physiology. THE IRIS 
1117 
of the ciliary muscle by their contraction pull forward the choroid and relax the 
suspensory ligament. The elasticity of the lens at once causes it to bulge forward 
till it is again checked by the tension of the capsule."1 The pupil is at the same 
time slightly contracted. 
The Iris (iris, a rainbow) (Figs. 716, 719, 721, 723, 724, 727, 728, 729, 730, and 
744).-The iris has received its name from its various colors in different individ- 
uals. It is a thin, circular-shaped, contractile curtain, suspended in the aqueous 
humor behind the cornea, and in front of the lens, being perforated a little to the 
nasal side of its centre by a circular aperture, the pupil (pupilld) (Fig. 730), for 
the transmission of light. The pupil of a living person varies in size under the 
influence of light and in efforts at accommodation. In looking at a near object the 
pupil is small; in looking at a distant object it is large. In light the pupil contracts, 
in darkness it dilates; hence the pupil is a window which permits light to pass into 
the interior of the eye. The size of this window depends on the contraction or 
relaxation of the iris. The iris divides the aqueous chamber (the space between 
Cornea. 
•V 
I 
Circ. fibres 
of sclerotic. 
Canal of 
Schlenm. 
Spaces of 
Fontana. ■ 
Tris. 
.V 
Ciliary 
artery. 
Pars ciliaris 
retina. 
Radiating 
fibres of 
Ciliary muscle. 
Oirc. fibres 
of Ciliary muscle. 
Fig. 727.-Section of the eye, showing the relations of the cornea, sclerotic, and iris, together with the Ciliary 
muscle and the cavernous spaces near the angle of the anterior chamber. (Waldeyer.) 
the cornea and lens) into an anterior chamber and a posterior chamber which com- 
municate through the pupil (Figs. 714 and 716). Bv its circumference or ciliary mar- 
gin (margo ciliaris) (Figs. 727 and 728) the iris is continuous with the ciliary body, 
and it is also connected with the posterior elastic lamina of the cornea by means of 
the pectinate ligament (ligamentum pectinatum iridic) (Fig. 744). The pectinate 
ligament of the iris is derived from the posterior elastic layer of the cornea. This 
layer divides into numerous fibrillae and some of them reach the iris, and bridge 
the angle between the cornea and base of the iris (Deaver). The fibrillae which 
reach the iris constitute the ligament. In this ligament are numerous lymph- 
spaces, the spaces of Fontana (spatia anguli iridis [Fontanae]) (Fig. 727), and 
they join the canal of Schlemm to the anterior chamber of the eye. The inner or 
free edge of the iris forms the margin of the pupil, and is called the pupillary 
margin (viargo pupillaris') (Fig. 728). The surfaces of the iris are flattened, and 
1 Stewart, Manual of Physiology. 1118 
THE ORGANS OF SPECIAL SENSE 
look forward and backward, the anterior tow ard the cornea, the posterior toward 
the ciliary processes and lens. The iris is pigmented and the color of an individual's 
eyes depends upon this pigment. The anterior surface facies anterior) (Figs. 728 
and 744) of the iris is variously colored in different individuals, and is marked by 
lines which converge toward the pupil. The posterior surface (facies posterior) (Figs, 
726 and 744) is of a deep-purple tint, from being covered by two layers of pig- 
mented, columnar epithelium, which layers are continuous posteriorly with the 
pars ciliaris retinae. This pigmented epithelium is termed the pars iridica retinae, 
though it is sometimes named uvea, from its resemblance in color to a ripe grape. 
Structure.-The iris is composed of the following structures: 
1. In front is a layer of flattened endothelial cells placed on a delicate hyaline 
basement-membrane. This layer is continuous with the endothelial layer covering 
the membrane of Descemet, and in men with dark-colored irides the cells contain 
pigment-granules. 
2. Stroma (stroma iridis).-The stroma consists of fibres and cells. The former 
are made of fine, delicate bundles of fibrous tissue, of which some few fibres have 
CILIARY GANGLIATED 
PLEXUS 
CHOROID 
CILIARY 
MUSCLE 
CILIARY MARGIN 
OF IRIS' 
ATTACHED 
REMNANT OF 
CORNEAL 
MARGIN 
STROMA 
OF IRIS 
CILIARY ZONE 
OF IRIS' 
CONTRACTING 
FOLDS OF IRIS 
VASCULAR 
EMINENCES 
CIRCULUS 
MINOR' 
LARGE 
PIGMENT-CELL 
PUPILLARY ZONE 
OF IRIS 
-CRYPTS 
PUPILLARY 
MARGIN 
FREE BORDER 
OF PIGMENTARY 
LAYER 
Fig. 728.-Section of the iris. Anterior surface magnified. (Toldt.) 
a circular direction at the circumference of the iris, but the chief mass consists of 
fibres radiating toward the pupil. They form, by their interlacement, a delicate 
mesh, in which the vessels and nerves are contained. Interspersed between the 
bundles of connective tissue are numerous branched cells with fine processes. 
Many of them in dark eyes contain pigment-granules, but in blue eyes and the 
pink eyes of albinos they are unpigmented. 
3. The Muscular Fibre is involuntary and consists of circular and radiating 
fibres. The circular fibres (m. sphincter papillae) surround the margin of the pupil 
on the posterior surface of the iris, like a sphincter, forming a narrow band about 
one-thirtieth of an inch in width, those near the free margin being closely aggre- 
gated; those more external somewhat separated, and forming less complete circles. 
The radiating fibres (m. dilator papillae} converge from the circumference toward 
the centre, and blend with the circular fibres near the margin of the pupil. These 
fibres are regarded by some as elastic, not muscular, but Grunnert positively 
demonstrated them.1 The fibres are very small and are placed between the 
stroma and the posterior layer of endothelium. 
1 Von Graefe's Arch. f. Ophthal., Bd. xlvii. THE IRIS 
1119 
4. Pigment.-The situation of the pigment-cells differs in different irides. In 
the various shades of blue eyes the only pigment-cells are several layers of small 
round or polyhedral cells filled with dark pigment, situated on the posterior surface 
IRIS 
CILIARY 
MUSCLE* 
CILIARY 
GANGLIATED 
PLEXUS 
CHOROID^ 
CILIARY, 
nerves' 
^CILIARY 
NERVES 
POSTERIOR 
LONG CILIARY' 
ARTERY 
ANTERIOR RADICLES 
OF ONE OF THE 
VORTICOSE VEINS 
Fig. 729.-The ciliary gangliated plexus and the ciliary nerves entering the plexus. Outer surface of the 
middle or vascular coat of the eyeball. (Toldt.) 
of the iris and continuous with the pigmentary lining of the ciliary processes. The 
color of the eye in these individuals is due to this coloring-matter showing more 
or less through the texture of the iris. In the albino even this pigment is absent. 
ANTERIOR CILIARY ARTERIES 
CHOROID 
LONG CILIARY 
ARTERY 
ANTERIOR CILIARY ARTERIES 
Fig. 730.-Iris, front view. (Testut.) 
Tn the gray, brown, and black eye there are, as mentioned above, pigment-granules 
to be found in the cells of the stroma and in the endothelial layers on the front of 
the iris; to these the dark color of the eye is due. 1120 
THE ORGANS OF SPECIAL SENSE 
The Arteries of the Iris (Figs. 723, 725, 727, and 730).-The arteries of the iris are 
derived from the long posterior ciliary and anterior ciliary and from the vessels of the 
ciliary processes (see p. 1115). The long posterior ciliary arteries (Figs. 721 and 723), 
two in number, pass through the sclera, one on the inner and one on the outer side 
of the optic nerve, and pass forward between the sclera and choroid, and, having 
reached the attached margin of the iris (Figs. 721 and 730),divide into an upper and 
a lower branch, and, encircling the iris, anastomose with corresponding branches 
from the opposite side; into this vascular zone (circulus arteriosus major) (Fig. 744) 
the anterior ciliary arteries (Fig. 744), from the lachrymal and anterior ciliary from the 
muscular branches of the ophthalmic, pour their blood. From this zone vessels con- 
verge to the free margin of the iris, and these communicate by branches from one 
to another and thus form a second zone (circulus arteriosus minor) in this situation. 
The veins pass toward the ciliary margin and communicate with the veins of the 
ciliary processes and of the canal of Schlemm (Figs. 721 and 723). 
The Nerves of the Choroid and Iris (Figs. 719, 721, and 729).-The nerves of the 
choroid and iris are the short ciliary, the ciliary branches of the lenticular ganglion, 
and the long ciliary from the nasal branch of the opthalmic division of the fifth. They 
pierce the sclerotic around the entrance of the optic nerve, and run forward in the 
perichoroidal lymph-space in which they forma plexus, from which plexus filaments 
pass to supply the blood-vessels of the choroid. After reaching the iris they form 
a plexus around its attached margin; from this are derived non-medullated fibres 
which terminate in the circular and radiating muscular fibres. Their exact mode 
of termination has not been ascertained. Other fibres from the plexus terminate 
in a network on the anterior surface of the iris. The fibres derived from the motor 
root of the lenticular ganglion (third nerve) supply the circular fibres, while those 
derived from the sympathetic supply the radiating fibres. 
Membrana Pupillaris.-In the f cetus the pupil is closed by a delicate transparent 
vascular membrane, the membrana pupillaris, which divides the space into which 
the iris is suspended into two distinct chambers. This membrane contains numer- 
ous minute vessels, continued from the margin of the iris to those on the front part 
of the capsule of the lens. These vessels have a looped arrangement, and converge 
toward each other without anastomosing. Between the seventh and eighth months 
the membrane begins to disappear, by gradual absorption from the centre toward 
the circumference, and at birth only a few fragments remain. It is said some- 
times to remain permanent and produce blindness. 
The retina is a delicate nervous membrane, in which the fibres of the optic nerve 
are spread out and upon the surface of which the images of external objects are 
received. Its outer surface is in contact with the choroid; its inner with the vitreous 
body. Behind, it is continuous with the optic nerve; it gradually diminishes in 
thickness from behind forward; and, in front, extends nearly as far as the ciliary 
body, where it appears to terminate in a jagged margin, the ora serrata (Figs. 723, 
742, and 744). Here the nervous tissues of the retina end, but a thin prolongation 
of the membrane extends forward over the back of the ciliary processes and iris, 
forming the para ciliaris retinae and pars iridica retinae already referred to (Figs. 727 
and 744). This forward prolongation consists of the pigmentary layer of the retina, 
together with a stratum of columnar epithelium. The portion back of the ora 
serrata is called the physiological retina (pars optica retinae) (Fig. 744). The retina 
is soft, semitransparent, and of a purple tint in the fresh state, owing t( the presence 
of a coloring-material named rhodopsin or visual purple; but it soon becomes 
clouded, opaque, and bleached when exposed to sunlight. Exactly in the centre 
of the front surface of the posterior part of the retina, corresponding to the visual 
axis, and at a point in which the sense of vision is most perfect, is an oval yellowish 
III. The Tunica Interna or Retina (Figs. 723, 731, 733). THE TUNICA INTERNA OR RETINA 
1121 
spot, called, after its discoverer, the yellow spot of Sbmmerring {macula lute a.) (Figs. 
714 and 733), having a central depression, the fovea centralis. The retina in the 
situation of the fovea centralis is exceedingly thin, and the dark color of the choroid 
is distinctly seen through itf so that it presents more the appearance of a foramen, 
and hence the name foramen of Sbmmerring at first given to it. It exists only in 
man, the quadrumana, and some saurian reptiles. About one-eighth of an inch (3 
mm.) to the nasal side of the yellow spot and one-twenty-fourth of an inch below 
it, is the point of entrance of the optic nerve, the optic disk {porus opticus') (Figs. 
731 and 733). The circumference of the optic disk is slightly raised so as to form 
an eminence, the optic papilla {colliculus nervi optici)-, the central portion is 
depressed and is called the optic cup {excavatio papillae nervi optici). The arteria 
centralis retinae pierces its centre. This is the only part of the surface of the retina 
from which the power of vision is absent, and is termed the blind spot. 
LAMINA CRIBROSA 
OF SCLERA 
OPTIC 
PAPI LLA 
RETINA^ 
OPTIC 
EXCAVATION 
CHOROID 
SCLERA 
POSTERIOR 
SHORT CILIARY 
ARTERY AND' 
VEIN 
PIAL. 
SHEATH 
DURAL, 
sheath' 
ARACHNOID 
SHEATH' 
INTERVAGINAL 
SPACES 
BUNDLES OF 
OPTIC NERVE 
CENTRAL ARTERY AND 
VEIN OF RETINA 
Fig. 731.-The terminal portion of the optic nerve and its entrance into the eyeball, in horizontal section. (Toldt.) 
Structure.-The optical portion of the retina is an exceedingly complex structure, 
and, when examined microscopically by means of sections made perpendicularly 
to its surface, is found to consist of many layers of nervous structure. These ner- 
vous structures are bound together and supported by the sustentacular fibres. 
There are three layers: a middle or neuro-epithelial layer, an inner layer, and an 
outer or pigmentary layer. The neuro-epithelial layer is subdivided into four and 
the middle layer into six layers; hence the retina consists of eleven layers. The 
layers from within outward are as follows (Figs. 732, 734, 735, and 736): 
1. Membrana limitans interna. 
2. Layer of nerve-fibres (stratum opticum). 
3. Ganglionic layer, consisting of nerve-cells. 
4. Inner molecular, or plexiform, layer. 
5. Inner nuclear layer, or layer of inner granules. 
6. Outer molecular, or plexiform, layer. 
7. Henle's fibre-layer. 
8. Outer nuclear layer, or layer of outer granules. 
9. Membrana limitans externa. 
10. Jacob's membrane (layer of rods and cones). 
11. Pigmentary layer (tapetum nigrum). 
1. Inner layer 
2. Neuro-epithelial layer 
3. Outer layer THE ORGANS OF SPECIAL SENSE 
1122 
1. The Membrana Limitans Interna (Figs. 732, 734, and 735), is the most internal 
layer of the retina, and is in contact with the hyaloid membrane of the vitreous 
Pigmentary layer. 
Jacob's membrane. 
Membrana limitans externa. 
Outer nuclear layer. 
Outer molecular layer. 
Inner nuclear layer. 
Fibre of Muller. 
Inner molecular layer. 
Ganglionic layer. 
Layer of nerve-fibres. 
Membrana limitans interna. 
Fig. 732.-The layers of the retina with the exception of Henle's fibre-layer. (Diagrammatic.) (After Schultze.) 
humor. It is derived from the sup- 
porting jramework of the retina, with 
which tissue it will be described. 
2. The Layer of Nerve-fibres (Figs. 
732, 734, and 735) is formed by 
the expansion of the optic nerve. 
This nerve passes through all the 
other layers of the retina, except 
the membrana limitans interna, to 
reach its destination. As the nerve 
passes through the lamina cribrosa of 
the sclerotic coat, the fibres of which 
it is composed lose their medullary 
sheaths and are continued onward, 
through the choroid and retina, as 
simple axis-cylinders. When these 
non-medullated fibres reach the in- 
ternal surface of the retina, they radi- 
ate from their point of entrance over the surface of the retina, become grouped in 
bundles, and in many places, according to Michel, arranged in plexuses. Most 
of the fibres in this layer are centripetal, and are the direct continuations of the 
Sclerotic. 
Choroid. 
Retina. 
Fig.733.-The arteria centralis retinae, yellow spot, etc.,the 
anterior half of the eyeball being removed. (Enlarged.) THE TUNICA INTERNA OR RETINA 
1123 
axis-cylinder processes of the cells of the next layer. A few of the fibres are 
centrifugal, which are axis-cylinders of ganglion-cells within the brain. The cen- 
trifugal fibres in the layer of nerve-fibres pass through it and the next succeeding 
layer to ramify in the inner molecular and inner nuclear layers, where they termi- 
nate in enlarged extremities. The layer is thickest at the optic nerve entrance, 
and gradually diminishes in thickness toward the ora serrata. 
3. The Ganglionic Layer or the Inner Ganglionic Layer (Figs. 732, 734, and 735) 
consists of a single layer of large ganglion-cells; except in the macula lutea, 
where there are several strata. The cells are somewhat flask-shaped, the rounded 
internal margin of each cell resting on the preceding layer and sending off an axone 
which is prolonged as a nerve-fibre into the fibrous layer. From the opposite 
extremity numerous thicker processes (dendrites) extend into the inner molecular 
layer, where they branch out into flattened arborizations at different levels. The 
ganglion-cells vary much in size, and the dendrites of the smaller ones, as a rule, 
Figs. 734 and 735.- Vertical sections of the human retina. Fig. 734, half an inch from the entrance of the 
optic nerve. Fig. 735, close to the latter. 1. Layer of rods and cones, Jacob's membrane, bounded underneath 
by the membrana limitans externa. 2. Outer nuclear layer. 3. Outer molecular layer. 4. Inner nuclear layer. 
5. Inner molecular layer. 6. Ganglionic layer. 7. Layer of nerve fibres. 8. Sustentacular fibres of Muller. 
9. Their attachment to the membrana limitans interna. 
arborize in the inner molecular layer as soon as they enter it; while the processes 
of the larger cells ramify close to the inner nuclear layer. 
4. The Inner Molecular, the Plexiform or the Inner Reticular Layer (Fig. 732, 734, 
and 735) is made up of a dense reticulum of minute fibrils, formed by the inter- 
lacement of the dendrites of the ganglion-cells with those of the cells contained in 
the next layer, immediately to be described. Within the reticulum formed by 
these fibrils a few branched spongioblasts are sometimes embedded. 
5. The Inner Nuclear or Inner Granular Layer (Figs. 732, 734, and 735) is made up 
of a number of closely packed cells, of which there are three different kinds. (1) A 
large number of oval cells, which are commonly regarded as bipolar nerve-cells, and 
are much more numerous than either of the other kind. They each consist of a 
large oval body placed vertically to the surface, and containing a distinct nucleus. 
The protoplasm is prolonged into two processes; one of these passes inward into the 
inner molecular layer, is varicose in appearance, and ends in a terminal ramification, 
which is often in close proximity to the ganglion-cells (Fig. 736, I, c). The outer 
process passes outward into the outer molecular layer, and there breaks up into a THE ORGANS OF SPECIAL SENSE 
1124 
Fig. 736.-Elements of the retina of mammals, displayed by the chromate of silver method of Golgi. (Cajal.) (Copied from Quain's Anatomy.) THE TUNICA INTERNA OR RETINA 
1125 
number of branches. According to Cajal, there are two varieties of these pipolar 
cells: one in which the outer process arborizes around the knobbed ends of the 
rod-fibres, and the inner around the cells of the ganglionic layer; these he calls rod- 
bipolars (Fig. 736, i); the others are those in which the outer process breaks up in 
a horizontal ramification, in contact with the end of a cone-fibre; these are the 
cone-bipolars, and their inner process breaks up into its terminal ramifications in 
the inner molecular layer (Fig. 736, i). (2) At the innermost part of this inner 
nuclear layer is a stratum of cells, which are named Cajal amacrine cells, from the 
fact that they have no axis-cylinder process, but they give a number of short proto- 
plasmic processes which extend into the inner molecular layer and there ramify 
(Fig. 736, i). There are also at the outermost part of this layer some cells, the 
processes of which extend into and ramify in the outer molecular layer. These 
are the horizontal cells of Cajal. (3) Some few cells are also found in this layer, 
connected with the fibres of Muller and will be described with those structures. 
6. The Outer Molecular or Outer Reticular Layer or the Plexiform Layer (Figs. 
732, 734, and 735) is much thinner than the inner molecular layer; but, like it, 
consists of a dense network of minute fibrils, derived from the processes of the 
horizontal cells of the preceding layer and the outer processes of the bipolar cells, 
which ramify in it, forming arborizations around the ends of the rod-fibres and 
with the branched foot-plates of the cone-fibres. 
7. Henle's Fibre Layer is a non-granular layer in the neighborhood of the macula 
lutea, and is produced by elongations from the inner segments of rod-fibres and 
cone-fibres. 
8. The Outer Nuclear or Outer Granular Layer (Figs. 732, 734, and 735), like the 
inner nuclear layer, contains several strata of clear oval nuclear bodies; they are 
of two kinds, and on account of their being respectively connected with the rods 
and cones of Jacob's membrane (rod-fibres and cone-fibres) are named rod- 
granules and cone-granules. 
The rod-granules are much the more numerous, and are placed at different levels 
throughout the layer. Their nuclei present a peculiar cross-striped appearance, 
and prolonged from either extremity of the granule is a fine process; the outer 
process is continuous with a single rod of Jacob's membrane; the inner passes 
inward toward the outer molecular layer and terminates in an enlarged extremity, 
I. Section of the dog's retina, a. Cone-fibre, b. Rod-fibre and nucleus, e, d. Bipolar cells (inner granules) 
with vertical ramification of outer processes destined to receive the enlarged ends of rod-fibres, 
e. Bipolars with flattened ramification for ends of cone-fibres, f. Giant bipolar with flattened ramifica- 
tion. <7. Cell sending a neurone or nerve-fibre process to the outer molecular layer, h. Amacrine cell 
with diffuse arborization in inner molecular layer, i. Nerve-fibrils passing to outer molecular layer, 
j. Centrifugal fibres passing from nerve-fibre layer to inner molecular layer, m. Nervs-fibril passing 
into inner molecular layer, n. Ganglionic cells. 
II. Horizontal or basal cells of the outer molecular layer of the dog's retina. A. Small cell with dense arbori- 
zation. R. Large cell, lying in inner nuclear layer, but with its processes branching in the outer 
molecular, a. Its horizontal neurone. C. Medium-sized cell of the same character. 
III. Cells from the retina of the ox. a. Rod-bipolars with vertical arborizations, b, c, d, e. Cone-bipolars with 
horizontal ramification of outer process, h. Cell lying on the outer surface of the outer molecular 
layer, and ramifying within it. Amacrine cells within the substance of the inner molecular 
layer. 
IV. Neurones or axis-cylinder processes belonging to horizontal cells of the outer molecular layer, one of them, 
b, ending in a close ramification at a. 
V. Nervous elements connected with the inner molecular layer of the ox's retina. a. Amacrine cell, with 
long processes ramifying in the outermost stratum. B. Large amacrine with thick processes ramifying 
in second stratum. C. Flattened amacrine with long and fine processes ramifying mainly in the first 
and fifth strata. D. Amacrine with radiating tuft of fibrils destined for third stratum. E. Large 
amacrine, with processes ramifying in fifth stratum. F. Small amacrine, branching into second 
stratum. G, H. Other amacrines destined for fourth stratum, a. Small ganglion-cell sending its pro- 
cesses to fourth stratum, b. A small ganglion-cell with ramifications in three strata. C. A small cell 
ramifying ultimately in first stratum, d. A medium-sized ganglion-cell ramifying in fourth stratum. 
e. Giant-cell, branching in third stratum, f. A bistratified cell ramifying in second and fourth strata. 
VI. Amacrines and ganglion-cells from the dog. a. Amacrine with radiating tuft. B. Large amacrine passing 
to third stratum c and G. Small amacrines with radiations in second stratum. F. Small amacrine 
passing to third stratum. D. Amacrine with diffuse arborization. E. Amacrine belonging to fourth 
stratum, a, d, e, g. Small ganglion-cells ramifying in various strata. b,f. Large ganglion-cells show- 
ing two different characters of arborization, i. Bistratified cell. 
VII. Amacrines and ganglion-cells from the dog. a, b, C. Small amacrines ramifying in middle of molecular 
layer, b, d, g, h, i. Small ganglion-cells showing various kinds of arborization, f. A larger cell, similar 
in character to g, but with longer branch, a, c, e. Giant-cells with thick branches ramifying in the 
first, second, and third layers. L, L. Ends of bipolars branching over ganglion-cells. 
DESCRIPTION OF FIG. 736. 1126 
THE ORGANS OF SPECIAL SENSE 
and is embedded in the tuft into which the outer process of the rod-bipolars break 
up. In its course it presents numerous varicosities. 
The cone-granules, fewer in number than the rod-granules, are placed close to the 
membrana limitans externa, through which they are continuous with the cones of 
Jacob's membrane. They do not present any cross-striping, but contain a pyri- 
form nucleus which almost completely fills the cell. From their inner extremity a 
thick process passes inward to the outer molecular layer, upon which it rests by a 
somewhat pyramidal enlargement, from which are given off numerous fine fibrils, 
A B 
VI 
E'3Sn 
I 47 m 
D 2.5m 
V 
E22n 
I 42 m 
D4m 
External 
segment' 
IV 
E13m 
J 41 m 
P5.5m 
Intermediary 
disc 
Elliptoid 
III 
E 7 m 
I 24 m 
D7m 
Myoid- 
I 
E 6 m 
I 16 m 
D 7.5 m 
II 
Z 21m 
Z)7m 
Nucleus 
Fig. 737.-The cells of the rods of the 
retina in the frog. A, red rod; B, green 
rod. (Poirier and Charpy.) 
which enter the outer molecular 
layer, where they come in con- 
tact with the outer processes of 
the cone-bipolars. 
9. The Membrana Limitans 
Externa (Figs. 732,734, and 735), 
like the membrana limitans in- 
terna, is derived from the fibres 
of Muller, with which structures 
it will be described. 
10. Jacob's Membrane or the 
Layer of Rods and Cones (Figs. 
732, 734, and 735) consists of 
visual cells, and the elements 
which compose it are of two 
kinds, rod-cells and cone-cells, 
the former being much more 
numerous than the latter. 
The rod-cells (Fig. 737) are of nearly uniform size, and arranged perpen- 
dicularly to the surface. A rod-cell consists of a rod and a rod-fibre, and the 
fibre contains the nucleus. The rods are cylindrical and each consists of two por- 
tions, an outer segment and an inner segment, which are of about equal length. 
The segments differ from each other as regards refraction and in their behavior 
with coloring reagents, the inner portion becoming stained by carmine, iodine, etc., 
the outer portion remaining unstained with these reagents, but staining yellowish- 
brown with osmic acid. The outer portion of each rod is marked by transverse striae, 
and is made up of a number of thin disks superimposed on one another. It also 
Fig. 738.-Cones in the different regions of the retina. Z, near 
the ora serrata; II, at 3 mm. from the ora serrata; III, at an 
equal distance from the ora serrata and the papilla; IV, at the 
periphery of the fovea centralis; V, in the fovea centralis; VI, at 
the centre of the fovea centralis; E, length of the external seg- 
ment; /, length of internal segment; D, diameter of the internal 
segment. (Poirier and Charpy.) THE TUNICA INTERNA OR RETINA 
1127 
exhibits faint longitudinal markings. The inner portion of each rod, at its deeper 
part where it is joined to the outer process of the rod-granule, is indistinctly gran- 
ular; its more superficial part presents a longitudinal striation, being composed of 
fine, bright, highly refracting fibres. In most vertebrates the outer portion of the 
inner segment contains a fibrous body, the ellipsoid of Krause. The visual purple, or 
rhodopsin, is found only in the outer segments of the rods. At its inner end each rod 
is prolonged into a very fine fibre, the rod-fibre, which contains a nucleus, and which 
terminates in the outer nuclear layer, being somewhat enlarged at its termination. 
The cone-cells (Fig. 738) are conical or flask-shaped, their broad ends resting 
upon the membrana limitans externa, the narrow pointed extremity being turned 
to the choroid. Each cone-cell consists of two parts, the cone and the cone-fibre. 
The cones are shorter than the rods and exhibit an outer and an inner segment. 
The outer segment is a short conical process, which, like the outer segment of a 
rod, presents transverse striae. The inner segment resembles the inner portion 
of the rods in structure, presenting a superficial striated and deeper granular part; 
but differs from it in size, being bulged out laterally and presenting a flask shape. 
The inner segment of the cone, as does the rod, contains an ellipsoid of Krause. 
Each cone is prolonged into a cone-fibre, and at the junction of the cone with the 
fibre is the nucleus of the cone-cell. The cone-fibre passes to the outer nuclear 
layer, and terminates as an expansion from which very minute fibrils are given off. 
The chemical and optical characters of the rod-cells and cone-cells are identical. 
11. The Pigmentary Layer or Tapetum Nigrum (Fig. 732).-The most external layer 
of the retina, formerly regarded as a part of the choroid, consists of a single layer 
of hexagonal epithelial cells, loaded with pigment-granules. Each cell contains a 
flattened nucleus in the outer portion of the cell which is free from pigment at this 
point. These cells are smooth externally, where they are in contact with the 
choroid, but internally they are prolonged into fine, straight processes, which 
extend between the rods, this being especially the case when the eye is exposed to 
light. The pigment changes its position under the influence of light, and is dis- 
tributed through the entire cell. In the eyes of albinos, the cells of the pigmentary 
layer are present, but they contain no coloring-matter. In the eyes of many 
mammals also, as in the horse, and many of the carnivora, there is no pigment 
in the cells of this layer, and the choroid possesses a beautiful iridescent lustre, 
which is termed the tapetum lucidum. 
Supporting Framework of the Retina.-Almost all these layers of the retina are 
connected together by a supporting framework, formed by the supporting cells or 
supporting fibres of Muller or radiating fibres, from which the membrana limitans 
interna et externa are derived. These fibres are found stretched between the two 
limiting layers (Fig. 732), "like columns between a floor and a roof," and they 
oass through all the nervous layers except Jacob's membrane. Each commences 
on the inner surface of the retina by a conical hollow base, which sometimes 
contains a spheroidal body which stains deeply with haematoxylin, the edges of 
the bases of adjoining fibres being united and thus forming a boundary line, which 
is the membrana limitans interna. As they pass through the nerve-fibre and gan- 
glionic layers they give off few lateral branches; in the inner nuclear layer they give 
off numerous lateral processes for the support of the inner granules, while in the 
outer nuclear layer they form a network, the fibre-baskets, around the rod and 
cone-fibrils, and unite to form the external limiting membrane at the bases of 
the rods and cones. In the inner nuclear layer each fibre of Muller presents a clear 
oval nucleus, which is sometimes situated at the side of, sometimes altogether 
within, the fibre. The supporting framework of the retina contains neuroglia cells. 
The Path of Light Stimuli.-The stimulus is first received by the rod and cone- 
cells (the visual cells), and is transmitted to the bipolar cells of the inner nuclear 
layer and then to the cells of the ganglionic layer, which send fibres by way of the 
optic nerve to the brain. 1128 
THE ORGANS OF SPECIAL SENSE 
Macula Lutea and Fovea Centralis.- Ihe structure of the retina at the yellow 
spot presents some modifications. In the macula lutea (1) the nerve-fibres are 
wanting as a continuous layer; (2) the ganglionic layer consists of several strata 
of cells, instead of a single layer; (3) in Jacob's membrane there are no rods, but 
only cones, and these are longer and narrower than in other parts; and (4) in the 
outer nuclear layer there are only cone-fibres, which are very long and arranged 
in curved lines. At the fovea centralis the only parts which exist are the cones 
of Jacob's membrane, the outer nuclear layer, the cone-fibres of which are almost 
horizontal in direction, and an exceedingly thin inner granular layer, the pigment- 
ary layer, which is thicker and its pigment more pronounced than elsewhere. The 
color of the macula seems to imbue all the layers except Jacob's membrane; it is 
of a rich yellow, deepest toward the centre, and does not appear to consist of 
pigment-cells, but simply a staining of the constituent parts. 
At the Ora Serrata (Fig. 723) the nervous layers of the retina terminate abruptly, 
and the retina is continued onward as a single layer of elongated columnar cells 
covered by the pigmentary layer. This prolongation is known as the pars ciliaris 
retinae (Fig. 727), and can be traced forward from the ciliary processes on to the 
back of the iris, where it is termed the pars iridica retinae or uvea. 
From the description given of the nervous elements of the retina it will be 
seen that there is no direct continuity between the structures which form its differ- 
ent layers except between the ganglionic and nerve-fibre layers, the majority 
of the nerve-fibres being formed of the axones of the ganglionic cells. In the 
inner molecular layer the dendrites of the ganglionic layer interlace with those 
of the cells of the inner nuclear layer, while in the 
outer molecular layer a like synapsis occurs between 
the processes of the inner granules and the rod and 
cone elements. 
The Arteria Centralis Retinae (Figs. 723 and 731) 
and its accompanying vein, vena centralis retinae, 
pierce the optic nerve, and enter the globe of the eye 
through the porus opticus. It immediately bifurcates 
into an upper and a lower branch, and each of these 
again divides into an inner or nasal, and an outer or 
temporal, branch, which at first run between the 
hyaloid membrane and the nervous layer; but they 
soon enter the latter, and pass forward, dividing 
dichotomously. From these branches a minute capillary plexus is given off, which 
does not extend beyond the inner nuclear layer. The macula receives small twigs 
from the temporal branches and others directly from the central artery; these do 
not, however, reach as far as the fovea centralis, which has no blood-vessels. The 
branches of the arteria centralis retinae do not anastomose with each other-in other 
words, they are "terminal arteries." In the foetus, a small vessel passes forward, 
through the hyaloid canal in the vitreous body, to the posterior surface of the cap- 
sule of the lens (Fig. 715). 
FOSSA 
PATELLAR IS 
VITREOUS 
BODY 
Fig. 739.-The vitreous body re- 
moved from the eye in the fresh state, 
with the saucer-shaped hollow in which 
the lens lies. Seen obliquely from the 
side and before. (Toldt.) 
THE REFRACTING MEDIA. 
The Refracting media are three, viz.: 
Aqueous humor. Vitreous body. Crystalline lens. 
I. The Aqueous Humor (Humor Aqueus). 
The aqueous humor completely fills the lymph space known as the aqueous 
chamber, the space which is bounded in front by the cornea and behind by the lens 
and its suspensory ligament and the ciliary body (Fig. 744). The aqueous chamber THE VITREOUS BODY 
1129 
is partly divided by the iris into two communicating parts, the anterior and posterior 
chambers (Figs. 714, 715, and 744.) The posterior chamber (camera oculi posterior} 
is only a narrow chink between the peripheral part of the iris, the suspensory 
ligament of the lens, and the ciliary processes. The anterior chamber (cumera oculi 
anterior is bounded in front by the cornea and behind by the iris. The external 
angle of the anterior chamber is bounded by the periphery of the cornea and of 
the iris. It is called the angle or sinus of the anterior chamber or the filtration angle 
{angulus iridis). It is by way of the filtration angle that any excess of aqueous 
humor passes by way of the spaces of Fontana and the canal of Schlemm (Fig. 
727) to the anterior ciliary veins and relieves tension. The aqueous humor is 
small in quantity (scarcely exceeding, according to Petit, four or five grains in 
weight), has an alkaline reaction, in composition is little more than water, less 
than one-fiftieth of its weight being solid matter, chiefly chloride of sodium. 
In the adult, these two chambers communicate through the pupil; but in the 
foetus of the seventh month, when the pupil is closed by the membrana pupillaris, 
the two chambers are quite separate. 
II. The Vitreous Body (Corpus Vitreum) (Figs. 712, 715, 739) 
The vitreous body forms about four-fifths of the entire globe. It is composed of 
a jelly-like tissue containing 98 per cent, water, some salts, and a little albumin, 
and called the vitreous humor (humor vitreus), connective-tissue fibres, and 
connective-tissue cells. It fills the concavity of the retina, and is hollowed in 
front, forming a deep concavity, the fossa patellaris (fossa hyaloided) (Fig. 739), 
for the reception of the lens. It is perfectly transparent, of the consistence 
of thin jelly, and is composed of an albuminous fluid enclosed in a delicate 
transparent membrane, the hyaloid membrane (membrana hyaloided), the outside 
of which is in contact with the membrana limitans interna of the retina. It 
has been supposed by Hannover, that from its inner surface numerous thin 
lamellae (stroma vitreum) are prolonged inward in a radiating manner, forming 
spaces in which the fluid is contained. In the adult, these lamellae cannot be 
detected even after careful microscopic examination in the fresh state, but in prep- 
arations hardened in weak chromic acid it is possible to make out a distinct 
lamellation at the periphery of the body; and in the foetus a peculiar fibrous 
texture pervades the mass, the fibres joining at the numerous points, and pre- 
senting minute nuclear granules at their point of junction. In the centre of 
the vitreous humor, running from the entrance of the optic nerve to the posterior 
surface of the lens, is a canal, filled with fluid and lined by a prolongation of the 
hyaloid membrane. This is the canal of Stilling, the hyaloid canal, or the canal of 
Cloquet (canalis hyaloid eus) (Fig. 715), which in the embryonic vitreous humor 
conveyed the minute vessel from the central artery of the retina to the back of 
the lens. 
The hyaloid membrane encloses the whole of the vitreous humor. In front of 
the ora serrata it is thickened by the accession of radial fibres and is termed the 
zonule of Zinn (zonula ciliaris) (Figs. 742 and 744). It presents a series of radially 
arranged furrows, in which the ciliary processes are accommodated and to which 
they are adherent, as evidenced by the fact that when removed some of their pig- 
ment remains attached to the zonule. The zonule of Zinn splits into two layers, one 
of which is thin and lines the fossa patellaris; the other is named the suspensory 
ligament of the lens; it is thicker, and passes over the ciliary body to be attached 
to the capsule of the lens a short distance in front of its equator. Scattered and 
delicate fibres are also attached to the region of the equator itself. This ligament 
retains the lens in position, and is relaxed by the contraction of the radial fibres 
of the Ciliary muscle, so that the lens is allowed to become more convex. Behind 1130 
THE ORGANS OF SPECIAL SENSE 
the suspensory ligament there is a sacculated canal, the canal of Petit (spatia 
zonulamay, which encircles the margin of the lens and which can be easily inflated 
through a fine blow-pipe inserted through the suspensory ligament. It is bounded 
in front by the anterior layer of the suspensory ligament of the lens, behind by the 
hyaloidea membrana, and internally by the capsule of the lens. The canal of 
Petit is a lymph-space. All the spaces of the canal of Petit communicate with the 
posterior chamber of the eye. 
In the foetus, the centre of the vitreous humor presents the hyaloid canal or 
canal of Stilling, already referred to, which transmits a minute artery, the 
hyaloid artery, to the capsule of the lens. In the adult, no vessels penetrate its 
substance, although a lymph channel remains; so that its nutrition must be car- 
ried on by the vessels of the retina and ciliary processes, situated upon its exterior. 
III. The Crystalline Lens (Lens Crystallina) (Figs.716,723,740,741,742,743,744). 
The crystalline lens, enclosed in its capsule, is situated immediately behind the 
pupil, in front of the vitreous body, and is encircled by the ciliary processes, which 
slightly overlap its margin. 
The capsule of the lens (capsula lentis) (Fig. 744) is a transparent, highly elastic, 
and brittle membrane, which closely surrounds the lens, and is composed in part of 
POSTERIOR 
SURFACE 
ANTERIOR 
SURFACE 
ANTERIOR 
POLE 
POSTERIOR 
'pole 
AXIS OF 
LENS 
Fig. 740.-The crystalline lens, hardened 
and divided. (Enlarged.) 
Fig. 741.-The terms used in the orientation of the lens. (Toldt.) 
EQUATOR, 
OF LENS 
cuticular and in part of connective tissue. It is not white fibrous tissue, and is not 
true elastic tissue (Szymonowicz). Its outer surface is composed of lamella and 
possesses transverse striations. It rests, behind, in the fossa patellaris in the fore- 
part of the vitreous body (Fig. 739); in front, it is in contact with the free border 
of the iris, this latter receding from it at the circumference, thus forming the 
posterior chamber of the eye (Fig. 744); and it is retained in its position chiefly by 
the suspensory ligament of the lens, already described (Fig. 744). The capsule is 
much thicker in front than behind, and when ruptured the edges roll up with the 
outer surface innermost, like the elastic lamina of the cornea. 
The substance of the lens (substantia lentis) is an epithelial structure and takes 
origin from the ectoderm. It consists early in development of transparent 
cylindrical cells, which at a later period become higher at the posterior surface 
of the lens. Eventually very long cells form; they are known as lens-fibres (fibrae 
lentis), and are joined by a cement substance. The adult lens consists of lens- 
fibres, the anterior surface being covered by one layer of cubical epithelial cells, 
known as lens epithelium (epithelium lentis). This layer extends to the margin of 
the lens, at which point the cells gain in height and form lens-fibres. The lens- 
fibres at the margin are nucleated, the others are not. The lens-fibres run as 
meridians from the anterior surface backward. There is no epithelium on the 
posterior surface. THE CEYSTALLINE LENS 
1131 
In the foetus, a small branch from the arteria centralis retinae runs forward, 
as already mentioned, through the vitreous humor to the posterior part of the 
capsule of the lens, where its brandies radiate and form a plexiform network, 
which covers its surface, and they are continuous around the margin of the capsule 
with the vessels of the pupillary membrane and with those of the iris. In the adult 
no vessels enter its substance. 
Structure.-The lens is a transparent, biconvex body, the convexity being greater 
on the posterior than on the anterior surface (Fig. 741). The central points of its 
-SCLERA 
ZONULE 
OF ZINN5 
CORONA 
'CILIARIS 
ORBICULARIS 
'CILIARIS 
■CHOROID 
LENS 
(posterior 
surface) 
•RETINA 
ORA 
SERRATA 
Fig. 742.-The zonule of Zinn or the suspensory ligament of the lens viewed from behind in connection 
with the lens and the ciliary body. (Toldt.) 
anterior and posterior surfaces are known as its anterior and posterior poles (polus 
anterior lends et polus posterior lends) (Fig. 741). It measures from 9 to 10 mm. 
in the transverse diameter, and about 4 mm. in the antero-posterior. It consists 
of concentric layers (Fig. 740) of which the external in the fresh state are soft and 
easily detached (substantia cordcalis) (Fig. 744); those beneath are firmer, the cen- 
tral ones forming a hardened nucleus (nucleus lends) (Fig. 740). These laminae 
are best demonstrated by boiling or immersion in alcohol, and consist of minute 
parallel fibres, which are hexagonal prisms, the edges being dentated, and the 
A 
B 
Fig. 743.-Diagram to show the direction and arrangement of the radiating lines on the front and back of 
the foetal lens. A, from the front; B, from the back. 
dentations fitting accurately into each other; their breadth is about 5 0- of an 
inch. Faint lines radiate from the anterior and posterior poles to the circumference 
of the lens. In the adult there may be six or more of these, but in the fcetus they are 
only three in number and diverge from each other at angles of 120° (Fig. 743). On 
the anterior surface one line ascends vertically and the other two diverge down- 
ward and outward. On the posterior surface one ray descends vertically and 
the other two diverge upward. They correspond with the free edges of an equal 
number of septa in the lens, along which the ends of the lens-fibres come into 1132 
THE ORGANS OF SPECIAL SENSE 
apposition and are joined together by transparent amorphous substance. The 
fibres run in a curved manner from the septa on the anteror surface to those on 
the posterior surface. No fibres pass from pole to pole, but they are arranged 
in such a way that fibres which commence near the pole on the one aspect of 
the lens terminate near the peripheral extremity of the plane on the other, and 
vice versa. Each fibre of the outer layers of the lens contains a nucleus, and 
these nuclei form a layer, the nuclear layer on the surface of the lens. The nuclear 
layer is most distinct toward the circumference of the lens. 
INSERTION OF 
TENDON OF SUPERIOR, 
RECTUS MUSCLE 
ORA SERRATA 
PARS OPTICA 
RETINAE 
SCLERA* 
PARS CILIARIS RETINXE 
CHOROID 
PIGMENTARY LAYER 
OF RETINA 
ANTERIOR CILIARY 
ARTERIES AND 
VEINS 
PERICHOROIDAL SPACE 
CIRCULAR 
MAJOR 
ANGLE OF 
ANTERIOR^ 
CHAMBER 
CANAL OF> 
SCHLEMM 
RADIAL 
'Fl BRES 
CONJUNCTIVA 
EPISCLERAL 
CIRCULAR 
FIBRES 
CILIARY 
PROCESS 
CON NECTIVE- 
TISSUE" 
LIGAM ENTUM 
PECTINATUM 
RADIATING FIBRES 
'OFZONULE OFZINN 
IRIDIS 
RIMA 
CORNEALIS* 
ZONULE OF ZINN 
ZONULAR SPACES 
EDGE OF 
cornea' 
POSTERIOR CHAMBER 
OF EYE 
iris (ante- 
rior surface) • 
EPITHELIUM OF 
LENS CAPSULE 
CAPSULE 
OF LENS 
ANT.CHAMBER 
OF EYE 
CORTICAL SUBSTANCE 
"OF LENS 
POSTERIOR 
SURFACE- 
OF CORNEA 
NUCLEUS 
OF LENS 
EPITHELIUM' 
OF CORNEA 
ANTERIOR 
ELASTIC 
LAMINA 
POSTERIOR ELASTIC 
LA M I N A 
SPHINCTER 
OF PUPIL 
PIGM ENTARY 
LAYERS OF IRIS 
STROMA OF IRIS 
Fig. 744.-The upper half of a sagittal section through the front of the eyeball. (Toldt.) 
The changes produced in the lens by age are the following: 
In the foetus its form is nearly spherical, its color of a slightly reddish tint, it 
is not perfectly transparent, and is so soft as to break down readily on the slightest 
pressure. 
In the adult the posterior surface is more convex than the anterior; it is color- 
less, transparent, and firm in texture. 
In old age it becomes flattened on both surfaces, slightly opaque, of an amber 
tint, and increases in density. 
Arteries of the Globe of the Eye.-The arteries of the globe of the eye are the short 
posterior ciliary, long posterior ciliary, and anterior ciliary arteries, and the arteria 
centralis retinae. THE CRYSTALLINE LENS 
1133 
The short posterior ciliary arteries (aa. ciliares posteriores breves) (Figs. 721, 723, 
and 725) are from eight to sixteen in number. They arise from the ophthalmic 
branch of the internal carotid, pass through the sclerotic coat near the optic 
nerve, and are distributed to the choroid. 
There are two long posterior ciliary arteries (aa. ciliares posteriores longae) (Figs. 
721, 723, and 730), one on each side of the optic nerve. They are branches of the 
ophthalmic. They pass through the sclerotic external to the short ciliary arteries, 
and extend forward in the choroid. In the ciliary body they form an anastomosis 
with the anterior ciliary arteries. The anastomosis is known as the circulum iridis 
major (Figs. 723 and 744). Branches from this circle pass to the iris, and at the 
periphery of the sphincter of the iris form the circulum iridis minor. The muscular 
branches and the lachrymal branch of the ophthalmic give off the anterior ciliary 
arteries (aa. ciliares anteriores), six or eight in number. They pass along tendons 
of the muscles of the eyeball, reach the sclera, and pass upon the sclera to the 
corneal margin (Fig. 730). Branches are given off which pass backward to supply 
the anterior half of the sclera, and which are known as episcleral arteries (aa. 
episclerales) (Fig. 723). Two branches are given off which pass forward to the 
conjunctiva bulbi, which are known as the anterior conjunctival arteries (aa. con- 
junctivales anterioreq), which anastomose with the posterior conjunctival branches 
from the palpebral arteries, and which give branches to the delicate vascular net- 
work of the corneal margin which is in the annulus conjunctivae (Spalteholz). 
Eight or even more branches form the anterior ciliary arteries. They pass through 
the sclerotic near the sclero-corneal junction, and participate in the formation of the 
circulum iridis major. 
The Veins of the Globe of the Eye (Figs. 721, 722, and 723).-The veins are seen 
on the outer surface of the choroid. They have a whorl-like formation and empty 
into four or five large veins, the venae vorticosae. These four, five, or six equidistant 
venae vorticosae pierce the sclerotic midway between the margin of the cornea 
and the entrance of the optic nerve, and empty into the ophthalmic vein. Another 
set of veins accompany the anterior ciliary arteries, and are known as the anterior 
ciliary veins (vv. ciliares anteriores). They are derivatives of the venous sinus of 
the sclera in the canal of Schlemm. They form a circular plexus. They receive 
vessels, the ciliary muscle, and pass through the sclera close to the corneal margin. 
Posterior ciliary veins (vv. ciliares posteriores) receive vessels which gather venous 
blood from the outer surface of the sclera near the optic nerve. The posterior 
ciliary veins join anteriorly with the venae vorticosae. After emerging from the 
sclera they receive anterior conjunctival branches, and by means of episcleral 
veins communicate with the venae vorticosae. 
The Lymphatic Passages of the Eyeball.-The conjunctiva contains lymph- 
vessels. The eyeball contains lymph-spaces, but no lymph-vessels 
There are two sets of lymph-spaces in the eyeball, the anterior and posterior. 
The anterior lymph-spaces are the spaces of the cornea, of the iris, of the 
anterior chamber, and of the posterior chamber. 
The lymph from the intralamellar lymph-spaces of the cornea enters the con- 
junctival lymphatics at the margin of the cornea. 
The lymph-spaces of the iris open into the anterior chamber by the crypts of 
the iris and at the margin of the iris join the spaces of Fontana. 
The aqueous humor fills the anterior and posterior chambers, but is furnished 
by the vessels in the posterior chamber; in part by the vessels of the ciliary body, 
and in part by the vessels of the posterior surface of the iris. The lymph thus 
secreted passes by way of the pupil into the anterior chamber, and then is taken 
up by the spaces of Fontana, the canal of Schlemm, and the anterior ciliary veins.1 
' Deaver's Anatomy. 1134 
THE ORGANS OF SPECIAL SENSE 
The posterior lymph-spaces are the hyaloid canal, the perichoroidal lymph- 
space, the space of Tenon, the intervaginal space of the optic nerve, and the supra- 
vaginal space (Deaver). 
The hyaloid canal (Figs. 712 and 715) passes between the posterior surface of 
the lens and the optic disk. In the embryo the canal holds an artery, the hyaloid 
artery. During development the artery disappears, but a lymph channel remains. 
The hyaloid canal opens into the intervaginal space of the optic nerve. Between 
the sclerotic and the choroid is the perichoroidal lymph-space (Fig. 744). It is 
around the choroid vessels and the venae vorticosae, and empties into Tenon's 
space by means of openings through the sclera about the venae vorticosae. 
Tenon's space (Figs. 712 and 713) is between the sclera and the capsule of Tenon. 
It receives lymph from the perichoroidal space, and empties into the supra- 
vaginal space. 
The optic nerve (Fig. 731) has a sheath of dura and a sheath of pia, and 
between these sheaths is the intervaginal lymph-space. It is divided by a pro- 
longation of the cerebral arachnoid into a subdural space and a subarachnoid 
space, which empty into the corresponding spaces of the membranes of the brain. 
The supravaginal space is between the dural portion of the sheath of the optic 
nerve and a posterior prolongation of Tenon's capsule.1 
The Nerves of the Globe of the Eye.-The long ciliary nerves (rm. ciliaris longi), 
two in number, are derived from the nasal branch of the ophthalmic and the 
short ciliary nerves (nn. ciliares breves), twelve to fifteen in number, are derived 
from the ciliary or ophthalmic ganglion. Both the long and short ciliary nerves 
perforate the sclera in the neighborhood of the optic nerve (Fig. 721). They pass 
along the perichoroidal lymph-space, forming a plexus, and send filaments to the 
choroid vessels. In front of the Ciliary muscle they form a second plexus, and 
from it come branches which go to the Ciliary muscle and the muscular fibres and 
vessels of the iris, sclera, choroid, ciliary body, and iris (Fig. 729). The ciliary 
nerves supply the cornea. The circular fibres of the iris are innervated by the 
third nerve and the radiating fibres by the sympathetic. 
Surgical Anatomy.-From a surgical point of view the cornea may be regarded as consist- 
ing of three layers: (1) of an external epithelial layer, developed from the epiblast, and continu- 
ous with the external epithelial covering of the rest of the body, and therefore in its lesions resem- 
bling those of the epidermis; (2) of the cornea proper, derived from the mesoblast, and associated 
in its diseases with the fibro-vascular structures of the body; and (3) the posterior elastic layer 
with its endothelium, also derived from the mesoblast and having the characters of a serous 
membrane, so that inflammation of it resembles inflammation of the other serous and synovial 
membranes of the body. 
The cornea contains no blood-vessels, except at its periphery, where numerous delicate loops, 
derived from the anterior ciliary arteries, may be demonstrated on the anterior surface of the 
cornea. The rest of the cornea is nourished by lymph, which gains access to the proper sub- 
stance of the cornea and the posterior layer through the spaces of Fontana. This lack of a direct 
blood-supply renders the cornea very apt to inflame in the cachectic and ill-nourished. In spite 
of the absence of blood-vessels, wounds of the cornea usually heal rapidly. A wound which pene- 
trates the cornea opens the anterior chamber, and aqueous humor escapes. An ulcer may also 
open the anterior chamber. Through a wound or a perforated ulcer the pupillary margin of the 
iris may prolapse. A trivial injury of the cornea is repaired by transparent tissue. A severe 
injury is repaired by fibrous tissue, and opacity results. A slight opacity resembling a cloud of 
gray smoke is called nebula; a more marked white opacity is called leucoma. 
In abscess of the cornea pus gravitates between the layers to the lower part of the cornea and 
the purulent collection assumes a crescentic shape (onyx). 
The arcus senilis, seen in the aged, is a condition of haziness or opacity at the corneal margin 
due to fatty degeneration of the tissue of the cornea. It signifies interference with the blood- 
supply, because of senile degeneration of adjacent vessels. In cases of granular lids there is a 
peculiar affection of the cornea, called pannus, in which the anterior layers of the cornea become 
vascularized, and a rich network of blood-vessels may be seen on the cornea; and in interstitial 
keratitis new vessels extend into the cornea, giving it a pinkish hue, to which the term salmon 
patch is applied. The cornea is richly supplied with nerves, derived from the ciliary nerves, which 
1 For the lymphatic channels of the eyeball see Deaver's Surgical Anatomy, vol. ii. p. 392. THE CRYSTALLINE LENS 
1135 
enter the cornea through the forepart of the sclerotic and form plexuses in the stroma, terminating 
between the epithelial cells by free ends or in corpuscles. In cases of glaucoma the ciliary nerves 
may be pressed upon as they course between the choroid and sclerotic (Fig. 719), and in conse- 
quence of the pressure upon them, the cornea, to which they are distributed, becomes anaes- 
thetic. When a scar forms on the cornea and the iris becomes adherent, the scar and the iris, 
and sometimes even the lens, may bulge forward from intraocular tension. This condition 
is staphyloma of the cornea. In conditions of impaired nutrition the cornea may be bulged for- 
ward by intraocular pressure. The line of least resistance is a little below the centre of the 
cornea, and it is bulged forward and strongly curved. This condition is known as conical cornea. 
The sclerotic has very few blood-vessels and nerves. The blood-vessels are derived from the 
anterior ciliary, and form an open plexus in its substance. As they approach the corneal margin 
this arrangement is peculiar. Some branches pass through the sclerotic to the ciliary body; others 
become superficial and lie in the episcleral tissue, and form arches, by anastomosing with each 
other, some little distance behind the corneal margin. From these arches numerous straight 
vessels are given off, which run forward to the cornea, forming its marginal plexus. In inflamma- 
tion of the sclerotic and episcleral tissue these vessels become conspicuous, and form a pinkish 
zone of straight vessels radiating from the corneal margin, commonly known as the zone of ciliary 
injection. In inflammation of the iris and ciliary body this zone is present, since the sclerotic 
speedily becomes involved when these structures are inflamed. But in inflammation of'the cornea 
the sclerotic is seldom much affected, though the cornea and sclerotic are structurally continuous. 
This would appear to be due to the fact that the nutrition of the cornea is derived from a different 
source from that of the sclerotic. The sclerotic may be ruptured subcutaneously without any 
laceration of the conjunctiva, and the rupture usually occurs near the corneal margin, where 
the tunic is thinnest. It may be complicated with lesions of adjacent parts-laceration of the 
choroid, retina, iris, or suspensory ligament of the lens-and is then often attended with hemor- 
rhage into the anterior chamber, which masks the nature of the injury. In some cases the lens 
has escaped through the rent in the sclerotic, and has been found under the conjunctiva. Wounds 
of the sclerotic, if they do not perforate, usually heal readily. If they extend through the sclerotic 
they cause diminished tension, are always dangerous, and are often followed by inflammation, 
suppuration, and by sympathetic ophthalmia. The sclerotic may be weakened by injury, inflam- 
mation, etc., and the weakened portion may bulge from intraocular pressure, and even a healthy 
sclera may bulge from excessive intraocular pressure. According to its situation the lesion is 
known as ciliary staphyloma, equatorial staphyloma, or posterior staphyloma. 
One of the functions of the choroid is to provide nutrition for the retina and to convey ves- 
sels and nerves to the ciliary body and iris. Inflammation of the choroid is therefore followed 
by grave disturbance in the nutrition of the retina, and is attended with early interference with 
vision. Purulent choroiditis is not confined to the choroid; the retina, the vitreous, and the entire 
uveal tract become involved, and even other structures may suffer. In its diseases it bears a con- 
siderable analogy to those which affect the skin, and, like it, is one of the places from which 
melanotic sarcomata may grow. These tumors contain a large amount of pigment in their cells, 
and grow only from those parts where pigment is naturally present. The choroid may be ruptured 
without injury to the other tunics, as well as participating in general injuries of the eyeball. In 
cases of uncomplicated rupture the injury is usually at its posterior part, and is the result of a 
blow on the front of the eye. It is attended by considerable hemorrhage, which for a time may 
obscure vision, but in most cases this is restored as soon as the blood is absorbed. 
The iris is the seat of a malformation, termed coloboma, which consists in a deficiency or 
cleft, which in a great number of cases is clearly due to an arrest in development. In these cases 
it is found at the lower aspect, extending directly downward from the pupil, and the gap fre- 
quently extends through the choroid to the entrance of the optic nerve. In some rarer cases the 
gap is found in other parts of the iris, and is then not associated with any deficiency of the choroid. 
The iris is abundantly supplied with blood-vessels and nerves, and is therefore very prone to 
become inflamed. And when inflamed, in consequence of the fact that the iris and ciliary body are 
continuous, and that their vessels communicate, iritis is usually associated with cyclitis, the dis- 
ease being called irido-cyclitis. And, in addition, inflammation of adjacent structures, the cornea 
and sclerotic, is apt to spread into the iris. The iris is covered with endothelium, and partakes of 
the character of a serous membrane, and, like these structures, is liable to pour out a plastic exuda- 
tion when inflamed, and contract adhesions, either to the cornea in front {synechia anterior}, or 
to the capsule of the lens behind {synechia posterior). In iritis the lens may become involved, 
and the condition known as secondary cataract may be set up. Tumors occasionally commence in 
the iris; of these, cysts, which are usually congenital and sarcomatous tumors, are the most common 
and require removal. Gummata are not unfrequently found in this situation. In some forms 
of injury of the eyeball, as the impact of a spent shot, the rebound of a twig, or a blow with a 
whip, the iris may be detached from the Ciliary muscle, the amount of detachment varying from 
the slightest degree to the separation of the whole iris from its ciliary connection. 
The Argyll-Robertson pupil shows no reaction to light, but retains reaction to accommodation 
and vision remains good. 1136 
THE ORGANS OE SPECIAL SENSE 
The retina, with the exception of its pigment-layer and its vessels, is perfectly transparent, 
and is invisible when examined by the ophthalmoscope, so that its diseased conditions are 
recognized by its loss of transparency. In retinitis, for instance, there is more or less dense and 
extensive opacity of its structure, and not unfrequently extravasations of blood into its sub- 
stance. Hemorrhages may also take place into the retina from rupture of a blood-vessel without 
inflammation. 
In optic neuritis, papillitis, or choked disk, the ophthalmoscope shows increase in vascularity, 
and swelling and opacity of the nerve, which extend beyond the disk margins. Optic atrophy 
is apt to follow. (Fig. 745 shows a normal optic disk.) 
The retina may become displaced from effusion of serum between it and the choroid or by 
blows on the eyeball, or may occur without apparent cause in progressive myopia, and in this 
case the ophthalmoscope shows an opaque, tremulous cloud. Glioma, a form of sarcoma, and 
essentially a disease of early life, is occasionally met with in connection with the retina. 
The lens has no blood-vessels, nerves, or connective tissue in its structure, and therefore is 
not subject to those morbid changes to which tissues containing these structures are liable. It 
does, however, present certain morbid or abnormal conditions of various kinds. Thus, variations 
in shape, absence of the whole or a part of the lens, and displacements are amongst its congenital 
dejects. Opacities may occur from injury, senile changes, malnutrition, or errors in growth or 
development. An opacity of the capsule, of the lens, or of both, is known as a cataract. Senile 
changes may take place in the lens, impairing its elasticity and rendering it harder than in youth, 
Fig. 745.-Ophthalmoscopic appearances of healthv 
fundus in a person of very fair complexion. Scleral 
ring well marked. Left eye, inverted image. (Wecker 
and Jaeger.) 
Fig. 746.-Ophthalmoscopic appearance of severe 
recent papillitis. Several elongated patches of blood 
near border of disk. (After Hughlings Jackson.) 
so that its curvature can only be altered to a limited extent by the Ciliary muscle. And, finally, 
the lens may be dislocated or displaced by blows upon the eyeball, and its relations to surround- 
ing structures altered by adhesions or the pressure of new growths. 
There are two particidar regions of the eye which require special notice: one of these is known 
as the " filtration area," and the other as the " dangerous area." The filtration area is the circum- 
corneal zone immediately in front of the iris. Here are situated the cavernous spaces of 
Fontana, which communicate with the canal of Schlemm, through which the chief transudation 
of fluid from the eye is now believed to take place. The dangerous area of the eye is the region 
in the neighborhood of the ciliary body, and wounds or injuries in this situation are peculiarly 
dangerous; for inflammation of the ciliary body is liable to spread to many of the other structures 
of the eye, especially to the iris and choroid, which are intimately connected by nervous and 
vascular supplies. Moreover, wounds which involve the ciliary region are especially liable to be 
followed by sympathetic ophthalmia, in which destructive inflammation of one eye is excited by 
some irritation in the other. 
Emmetropia is normal vision. In normal vision the practically parallel light rays from distant 
objects focus on the retina without effort; divergent rays from near objects are focused on the 
retina by an effort of accommodation. 
Hyperopia or hypermetropia is far-sightedness. In this condition the retina is in front of the 
principal focus when the eye is at rest. The patient endeavors to correct the failure by constant 
and tiresome efforts at accommodation. The condition is usually due to inordinate shortness of 
the axis of the eye, but may be due to loss of the lens, decreased convexity of the refractive sur- 
faces, or lessened refractive power in the refractive media of the eye. It is corrected by the use 
of convex glasses. the: eyelid 
1137 
Myopia is near-sightedness. In this condition the rays of light come to a focus in front of the 
retina, and the patient is subjected to continued eye-strain. It is usually due to too great length 
of the axis of the eye, but may result from increase in refractive power of refractive media. It is 
corrected by concave glasses. Sometimes, as a person with hyperopia begins to age, an increased 
refractive power of the lens causes myopia. The occurrence of myopia in a hyperopic eye is 
called second sight, and it enables the individual to cease wearing convex glasses. 
Exenteration of the contents of the orbit means removal of all the contents except those at the 
orbital apex. Even the periosteum is taken away. It is performed for malignant disease. 
Evisceration of the eyeball is performed by making a circular incision at the corneal margin and 
removing the internal and middle coats and the contents of the globe. The sclera is not removed. 
A glass ball is inserted into the scleral sheath, and the sclera is closed over the ball by vertical 
.stitches, and the conjunctiva is closed over it by transverse stitches. The operation is performed 
for leucoma or staphyloma of the cornea. An artificial eye (a shell) is placed over the stump 
when healing is complete. 
Enucleation, or excision of the eyeball, differs from exenteration of the orbital contents in the 
fact that only the eyeball is removed. A circular incision through the ocular conjunctiva 
is carried around and near to the corneal margin. The conjunctiva and capsule of T£non are 
pushed back and the Rectus muscles are clamped and divided back of the clamp. Traction 
is made upon the globe in a forward and inward direction, and the optic nerve and adjacent 
structures are cut with scissors from the outer aspect of the globe. The eye is then pulled out of 
the orbit, and all structures which tend to retain it are divided. The stumps of the Recti muscles 
are sewed together. 
THE APPENDAGES OF THE EYE (TUTAMINA OCULI). 
The appendages of the eye include the eyebrows, the eyelids, the conjunctiva, 
and the lachrymal apparatus-viz., the lachrymal gland, the lachrymal sac, and the 
nasal duct. 
The Eyebrow (Supercilium). 
The eyebrows are two arched eminences of integument which surmount the 
upper circumference of the orbit on each side, and support numerous short, thick 
hairs, directed obliquely on the surface. The hairs may entangle foreign bodies 
and lessen somewhat the force of blows. In structure the eyebrows consist of 
thickened integument, connected beneath with the Orbicularis palpebrarum, 
Corrugator supercilii, and Occipito-frontalis muscles. These muscles serve, by 
their action on this part, to control to a certain extent the amount of light 
admitted into the eye. 
The Eyelid (Palpebra) (Figs. 747, 748). 
The eyelids are two thin, movable folds placed in front of the eye, and by closure 
protecting the eye from injury. The eyelids are composed of skin, superficial 
fascia, and alveolar tissue, fibres of the Orbicularis palpebrarum muscle, palpebral 
and orbito-tarsal ligaments, tarsal cartilages, and conjunctiva. The upper lid 
also contains the Levator labii superioris muscle. In the lids are blood-vessels, 
lymph-vessels, nerves, and Meibomian glands. There are two lids, the upper 
(palpebra superior) and the lower (palpebra inferior). The upper lid is the larger 
and the more movable of the two, and is furnished with a separate elevator 
muscle, the Levator palpebrae superioris. Each lid consists of two portions. The 
part near the orbital margin, "whose groundwork is formed merely by the thin 
palpebral fascia {septum orbitale)"' is called the orbital portion (pars orbitalis). 
The part in 'which the tarsus lies is called the tarsal portion (pars t ar satis). Between 
the two portions in each lid is a sulcus, called, in the upper lid, the superior crbito- 
palpebral sulcus (sulcus orbitopalpebralis superior), and, in the lower lid, the infericr 
orbito-palpebral sulcus (sulcus orbitopalpebralis inferior). When the eyelids are 
1 An Atlas of Human Anatomy. By Carl Toldt, assisted by A. D. Rosa. Translated by M. Eden Paul. 1138 
THE ORGANS OF SPECIAL SENSE 
opened an elliptical space, the interpalpebral slit (fissura palpebrarum), is left 
between their margins, the angles of which correspond to the junction of the upper 
and lower lids, and are called canthi. 
The Canthi.-The outer canthus (angulus oculi lateralis) is more acute than the 
inner, and the lids here lie in close contact with the globe; but the inner canthus 
(angulus oculi medialis) is prolonged for a short distance inward toward the nose. 
The two lids are separated at the inner canthus by a triangular space, the lacus 
lacrimalis. At the commencement of the lacus lacrimalis, on the margin of each 
eyelid, is a small conical elevation, the lachrymal papilla, the apex of which is 
pierced by a small orifice, the punctum lacrimale (Fig. 751), the commencement of 
the lachrymal canal (Fig. 750). When the lids are closed a space remains between 
them and the globe to permit of the flow of tears inward (rivus lacrimalis). 
The Eyelashes (ct7ia)(Fig. 748).-The eyelashes are attached to the free edges of 
the eyelids; they are short, thick, curved hairs, arranged in a double or triple row 
at the margin of the lids; those of the upper lid, more numerous and longer than 
the lower, curve upward; those of the lower lid curve downward. Because of this 
arrangement the two sets do not interlace in closing the lids. Near the attachment 
of the eyelashes are the openings of sebaceous glands (glandulae sebaceae) (Fig. 748) 
and of a number of glands, glands of Moll (glandulae ciliares [Molli]) (Fig. 748), 
arranged in several rows close to the free margin of the lid. They are regarded as 
enlarged and modified sweat-glands. On the inner surface are the Meibomian 
glands (glandulae tarsales [Meibomi]) (Fig. 750). Internal to the openings of the 
lachrymal canaliculi there are neither lashes nor Meibomian glands. 
LACHRYMAL ARTERY. 
AND NERVE 
.SUPRAORBITAL VES- 
SELS AND NERVE 
EXTERNAL LATERAL, 
LIGAMENT 
-LACHRYMAL SAC 
.INTERNAL LATE- 
RAL LIGAMENT 
Fig. 747.-The tarsi and their ligaments. Kight eye, front view. (Testut.) 
Structure of the Eyelids (Fig. 748).-The eyelids are composed of the following 
structures, taken in their order from without inward: 
Integument, areolar tissue, fibres of the Orbicularis muscle, tarsal plate, and 
its ligament, Meibomian glands, and conjunctiva. The upper lid has, in addition, 
the aponeurosis of the Levator palpebrse. 
The integument is extremely thin, and continuous at the margin of the lids with 
the conjunctiva. 
The subcutaneous areolar tissue is very lax and delicate, seldom contains any 
fat, and is extremely liable to serous infiltration. 
The fibres of the Orbicularis muscle, where they cover the palpebrae (m. ciliaris 
[Rwlani]), are thin, pale in color, and possess an involuntary action. THE EYELID 
1139 
The tarsal plates are two thin elongated plates of dense connective tissue about 
an inch in length. They are placed one in each lid, contributing to their form 
and support. 
The superior tarsal plate, superior tarsus or superior tarsal body (tarsus superior) 
(Fig. 747), the larger, is of a semilunar form, about one-third of an inch in 
breadth at the centre, and becoming gradually narrowed at each extremity. To 
the anterior surface of this plate the aponeurosis of the Levator palpebrae is 
attached. 
The inferior tarsal plate, inferior tarsus or inferior tarsal body (tarsus inferior} 
(Fig. 747), the smaller of the two, is thinner and of an elliptical form. 
The free or ciliary margin of these plates is thick, and presents a perfectly 
straight edge. The attached or orbital margin is connected to the circumference of 
the orbit by the fibrous membrane of the 
lids, with which it is continuous. The 
outer angle of each plate is attached to 
the malar bone by the external tarsal or 
external lateral ligament, or the external 
palpebral ligament or raphd (ligamentum 
pilpe'rralis lateralis) (Fig. 747). The inner 
angles of the two plates terminate at the 
commencement of the lacus lacrimalis; 
they are attached to the nasal process 
of the superior maxilla by the internal 
tarsal or internal lateral or internal palpe- 
bral ligament or the tendo oculi (ligamen- 
tum pabpebrale mediale) (Fig. 747). 
'Elie fibrous membrane of the lids con- 
stitutes the orbito-tarsal ligaments or the 
palpebral fasciae. In reality these so-called 
ligaments are fascial expansions situated 
one in each lid, and are attached margin- 
ally to the edge of the orbit, where they 
are continuous with the periosteum. The 
superior ligament blends with the tendon 
of the Levator palpebrae, the inferior with 
the inferior tarsal plate. Externally the 
superior and inferior ligaments fuse to 
form the external tarsal ligament or raphe 
just referred to; internally they are much 
thinner, and, becoming separated from 
the internal tarsal ligament, are fixed to 
the lachrymal bone immediately behind 
the lachrymal sac. Together the liga- 
ments form an incomplete septum, the 
orbital septum (septum orbit ale), which is 
perforated by the vessels and nerves which 
pass from the orbital cavity to the face 
and scalp. 
The Meibomian or Tarsal Glands (glandulae tarsales [Meibomi\) (Figs. 748 and 
750).-The Meibomian or tarsal glands are situated upon the inner surface of the 
eyelids between the tarsal plates and conjunctiva, and may be distinctly seen 
through the mucous membrane on everting the eyelids, presenting the appearance 
of parallel strings of pearls. They are about thirty in number in the upper eyelid, 
and somewhat fewer in the lower. They are embedded in grooves in the inner 
Fig. 748.-Vertical section through the upper eye- 
lid. a. Skin. b. Orbicularis palpebrarum, b'. Mar- 
ginal fasciculus of orbicularis (ciliary bundle), c. 
Levator palpebrae. d. Conjunctiva, e. Tarsal plate. 
J. Meibomian gland, p. Sebaceous gland, h. Eye- 
lashes. i. Small hairs of skin. j. Sweat-glands, k. 
Posterior tarsal glands. (After Waldeyer.) 1140 
THE ORGANS OF SPECIAL SENSE 
surface of the tarsal plates, and correspond in length with the breadth of each plate; 
they are, consequently, longer in the upper than in the lower eyelid. Their ducts 
open on the free margin of the lids by minute foramina, which correspond in num- 
ber to the follicles. The use of their secretion is to prevent adhesions of the lids. 
Structure of the Meibomian Glands.-These glands are a variety of the cutaneous 
sebaceous glands, each consisting of a single straight tube or follicle, having a 
caecal termination, and with numerous small secondary follicles opening into it. 
rhe tubes consist of basement-membrane, lined at the mouths of the tubes by 
stratified epithelium; the deeper parts of the tubes and the secondary follicles are 
lined by a layer of polyhedral cells. They are thus identical in structure with the 
sebaceous glands. 
1 he conjunctiva is the mucous membrane of the eye. It lines the inner surface 
of the eyelids, is reflected over the forepart of the sclerotic and cornea, and joins 
the lids to the eyeball. In each of these situations its structure presents some 
peculiarities. 
The Palpebral Portion (tunica conjunctiva palpebrarum) (Fig. 750).-The palpe- 
bral portion of the conjunctiva lines the posterior surface of the lids. It is thick, 
opaque, highly vascular, and covered with numerous papillae, its deeper parts 
presenting a considerable amount of lymphoid tissue. At the margin of the lids 
it becomes continuous with the lining membrane of the ducts of the Meibomian 
glands, and, through the lachrymal canals, with the lining membrane of the 
lachrymal sac and nasal duct. At the outer angle of the upper lid the lachrymal 
ducts open on its free surface; and at the inner angle of the eye it forms a semi- 
lunar fold, the plica semilunaris (plica semilunaris conjunctivae) (Fig. 751). The 
folds formed by the reflection of the conjunctiva from the lids on to the eye are 
called the superior and inferior palpebral folds, the former being the deeper of the 
two. These folds form the superior and inferior conjunctival fornix (Fig. 749). 
The Bulbar Portion (tunica conjunctiva bulbi).-Upon the sclerotic the conjunc- 
tiva is loosely connected to the globe; it becomes thinner, loses its papillary struc- 
ture, is transparent, and only slightly vascular in health. Upon the cornea the con- 
junctiva consists only of epithelium, constituting the ante- 
rior layer of the cornea (conjunctival epithelium) already 
described (p. 1109). Lymphatics arise in the conjunc- 
tiva in a delicate zone around the cornea, from which the 
vessels run to the ocular conjunctiva. 
Fornix of Conjunctiva. - At the poinf of reflection of 
each fold of the conjunctiva from the lid on to the globe 
of the eye a pocket or arch is formed. These arches are 
termed the fornix conjunctivae (Fig. 749). 
Glands of Conjunctiva.-In the conjunctiva there are a 
number of mucous glands which are much convoluted. 
They are chiefly found in the upper lid. Other glands, 
analogous to lymphoid follicles, and called by Henle trachoma glands, are found 
in the conjunctiva, and, according to Stromeyer, are chiefly situated near the 
inner canthus of the eye. They were first described by Brush, in his description 
of Peyer's patches of the small intestines, as "identical structures existing in the 
under eyelid of the ox." 
The Nerves of the Conjunctiva.-The nerves in the conjunctiva are numerous and 
form rich plexuses. According to Krause, they terminate in a pecidiar form of 
tactile corpuscle, which he terms the terminal bulb. 
The Caruncula Lacrimalis.-The caruncula lacrimalis is a small, reddish, conical- 
shaped body, situated at the inner canthus of the eye, and filling up the small 
The Conjunctiva (Figs. 714, 715, 727, 749). 
-'SUPERIOR FORNIX 
cl 
S I 
c' 
% 
6 
•INFERIOR FORNIX 
Fig. 749.-Sagittal section 
of eye, showing superior and 
inferior fornices of the con- 
junctiva. (Testut.) THE LACHRYMAL APPARATUS 
1141 
triangular space in this situation, the lacus lacrimalis. It consists of an island 
of skin containing sebaceous and sweat-glands, and is the source of the whitish 
secretion which constantly collects at the inner angle of the eye. A few slender 
hairs are attached to its surface. On the outer side of the caruncula is a slight 
semilunar fold of conjunctiva, the concavity of which is directed toward the 
cornea; it is called the plica semilunaris (Fig. 751). Muller found smooth mus- 
cular fibres in this fold, and in some of the domesticated animals a thin plate of 
cartilage has been discovered. This structure is considered to be the rudiment 
of the third eyelid in birds, the membrana nictitans. 
The Lachrymal Apparatus (Apparatus Lacrimalis) (Figs. 750, 751). 
The lachrymal apparatus consists of the lachrymal gland, which secretes the 
tears, and its excretory ducts, which convey the fluid to the surface of the eye. 
This fluid is carried away by the lachrymal canals into the lachrymal sac, and along 
the nasal duct into the cavity of the nose. 
The Lachrymal Glands (glandula lacrimalis).-The lachrymal gland is lodged 
in a depression at the outer angle of the orbit, on the inner side of the external 
Puncta lachrymalia. 
Fig. 750.-The Meibomian glands, etc., seen from the inner surface of the eyelids. 
angular process of the frontal bone. It is of an oval form, about the size and 
shape of an almond. Its upper convex surface is in contact with the periosteum 
of the orbit, to which it is connected by a few fibrous bands. Its under concave 
surface rests upon the convexity of the eyeball and upon the Superior and External 
recti muscles. Its vessels and nerves enter its posterior border, whilst its anterior 
margin is closely adherent to the back part of the upper eyelid, where it is covered 
to a slight extent by the reflection of the conjunctiva. The forepart of the gland 
is separated from the rest by a fibrous septum; hence it is sometimes described as 
a separate lobe, called the inferior lachrymal gland, palpebral portion of the gland, 
or the accessory gland of Rosenmuller (glandula lacrimalis inferior), the back part 
of the gland then being called the superior lachrymal gland (glandula lacrimalis 
superior). The ducts of the lachrymal gland, from six to twelve in number, 
run obliquely beneath the mucous membrane for a short distance, and, separating 
from each other, open by a series of minute orifices on the upper and outer half of 
the conjunctiva near its reflection on to the globe. These orifices are arranged in 
a row, so as to disperse the secretion over the surface of the membrane. 
Structure of the Lachrymal Gland.-In structure and general appearance the 
lachrymal resembles the serous salivary glands. In the recent state the cells are so 1142 
THE ORGANS OF SPECIAL SENSE 
crowded with granules that their limits can hardly be defined. Each cell contains 
an oval nucleus, and the cell-protoplasm is finely fibrillated. 
rhe Lachrymal Canaliculi or Canals (Fig. 751) commence at the minute orifices, 
puncta lacrimalia, on the summit of a small conical elevation, the lachrymal papilla 
or caruncle (carunculus lacrimalis), seen on the margin of the lids at the outer ex- 
tremity of the lacus lacrimalis. The superior canal (ductus lacrimalis superior), the 
smaller and shorter of the two, at first ascends, and then bends at an acute angle, 
and passes inward and downward to the ampulla. The inferior canal (ductus 
lacrimalis inferior) at first descends, 
and then, abruptly changing its course, 
passes almost horizontally inward to 
the ampulla. These canals are dense 
and elastic in structure and somewhat 
dilated at their angle. The mucous 
membrane is covered with scaly epi- 
thelium. The two canals join in a 
dilatation, the ampulla (ampulla ductus 
lacrimalis), which empties into the 
lachrymal sac. 
The Lachrymal Sac (saccus lacri- 
malis) (Fig. 751).-The lachrymal sac is 
the upper dilated extremity of the nasal 
duct, and is lodged in a deep groove 
formed by the lachrymal bone and the 
nasal process of the superior maxillary 
bone. It is oval in form, its upper ex- 
tremity being closed in and rounded, 
whilst below it is continued into the nasal duct. It is covered by a fibrous 
expansion derived from the tendo ocidi, and on its deep surface it is crossed by 
the Tensor tarsi muscle (Horner's muscle, p. 371), which is attached to the ridge 
on the lachrymal bone. 
Structure.-It consists of a fibrous elastic coat, lined internally by mucous mem- 
brane, the latter being continuous, through the ampulla and lachrymal canals, 
with the mucous lining of the conjunctiva, and, through the nasal duct, with the 
pituitary membrane of the nose. 
The Nasal Duct (ductus nasolacrimalis) (Fig. 751).-The nasal duct is a 
membranous canal, about three-quarters of an inch in length, which extends from 
the lower part of the lachrymal sac to the inferior meatus of the nose, where it 
terminates by a somewhat expanded orifice, provided with an imperfect valve, the 
valve of Hasner (plica lacrimalis [Hasneri]), formed by the mucous membrane. It 
is contained in an osseous canal formed by the superior maxillary, the lachrymal, 
and the inferior turbinated bones, is narrower in the middle than at each extrem- 
ity, and takes a direction downward, backward, and a little outward. It is lined 
by mucous membrane, which is continuous below with the pituitary lining of 
the nose. The membrane in the lachrymal sac and nasal duct is covered with 
columnar epithelium, as in the nose. This epithelium is in places ciliated. 
Puncta lachrymaHas 
Flo. 751.-The lachrymal apparatus. Right side. 
Surface Form. -The palpebral fissure, or opening between the eyelids, is elliptical in shape, 
and differs in size in different individuals and in different races of mankind. In the Mongolian 
races, for instance, the opening is very small, merely a narrow fissure, and this makes the eye- 
ball appear small in these races, whereas the size of the eye is relatively very constant. The 
normal direction of the fissure is slightly oblique, in a direction upward and outward, so that the 
outer angle is on a slightly higher level than the inner. This is especially noticeable in the Mon- 
golian races, in whom, owing to the upward projection of the malar bone and the shortness of 
the external angular process of the frontal bone, the tarsal plate of the upper lid is raised at its 
outer part and gives an oblique direction to the palpebral fissure. THE LACHRYMAL APPARATUS 
1143 
When the eyes are directed forward, as in ordinary vision, the upper part of the cornea is 
covered by the upper lid, and the lower margin of the cornea corresponds to the level of the 
lower lid, so that about the lower three-fourths of the cornea is exposed under ordinary circum- 
stances. On the margins of the lids, about a quarter of an inch from the inner canthus, are two 
small openings, the puncta lacrimalia, the commencement of the lachrymal canals. They are 
best seen by everting the eyelids. In the natural condition they are in contact with the con- 
junctiva of the eyeball, and are maintained in this position by the Tensor tarsi muscle, so that 
the tears running over the surface of the globe easily find their way into the lachrymal canals. 
The position of the lachrymal sac into which the canals open is indicated by a little tubercle, 
which is plainly to be felt on the lower margin of the orbit. The lachrymal sac lies immediately 
above and to the inner side of this tubercle, and a knife passed through the skin in this 
situation would open the cavity. The position of the lachrymal sac may also be indicated by 
the tendo oculi or internal tarsal ligament. If both lids be drawn outward, so as to tense the 
skin at the inner angle, a prominent cord will be seen beneath the tightened skin. This is the 
tendo oculi, which lies immediately over the lachrymal sac, bisecting it, and thus forming a useful 
guide to its situation. A knife entered immediately beneath the tense cord would open the 
lower part of the sac. A probe introduced through this opening can be readily passed down- 
ward through the duct into the inferior meatus of the nose. The direction of the duct is down- 
ward, outward, and backward, and this course should be borne in mind in passing the probe, 
otherwise the point may be driven through the thin bony walls of the canal. A convenient 
plan is to direct the probe in such a manner that if it were pushed onward it would strike 
the first molar tooth of the lower jaw on the same side of the body. In other words, the 
surgeon standing in front of his patient should carry in his mind the position of the first 
molar tooth, and should push his probe onward in such a way as if he desired to reach this 
structure. 
Beneath the internal angular process of the frontal bone the pulley of the Superior oblique 
muscle of the eye can be plainly felt by pushing the finger backward between the upper and inner 
angle of the eye and the roof of the orbit; passing backward and outward from this pulley, the 
tendon can be felt for a short distance. 
Surgical Anatomy.-The eyelids are composed of various tissues, and consequently are liable 
to a variety of diseases. The skin which covers them is exceedingly thin and delicate, and is 
supported on a quantity of loose and lax subcutaneous tissue which contains no fat. In conse- 
quence of this it is very freely movable, and is liable to be drawn down by the contraction of 
neighboring cicatrices. Such contractions may produce an eversion of the lid known as ectropion. 
Inversion of the lids {entropion) from spasm of the Orbicularis palpebrarum or from chronic 
inflammation of the palpebral conjunctiva may also occur. In some individuals there is an extra 
row of eyelashes on the inner margin of the lid, directed toward the cornea {distichiasis). Trich- 
iasis is a condition in w hich the lashes are directed toward the eye, but there is not inversion of 
the lid. The eyelids are richly supplied with blood, and are often the seat of vascular growths, 
such as navi. Rodent ulcer also frequently commences in this situation. The loose cellular tissue 
beneath the skin is liable to become extensively infiltrated either with blood or inflammatory 
products, producing very great swelling. Even from very slight injuries to this tissue the extrava- 
sation of blood may be so great as to produce considerable swelling of the lids and complete 
closure of the eye, and the same is the case when inflammatory products are poured out. The 
follicles are liable to become inflamed, constituting the disease known as marginal blepharitis, 
blepharitis ciliaris, or '' blear-eye." Irregular or disorderly growth of the eyelashes not unfre- 
quently occurs, some of them being turned toward the eyeball and producing inflammation and 
follicles of the eyelashes or the sebaceous glands associated with these follicles may be the seat of 
inflammation, constituting the ordinary hordeolum or "sty." The Meibomian glands are affected 
in the so-called " tarsal tumor;" the tumor, according to some, being caused by the retained secre- 
tion of these glands; by others it is believed to be a neoplasm connected with the gland. The Orbic- 
ularis palpebrarum may be the seat of spasm {blepharospasm), either in the form of slight quiv- 
ering of the lids or repeated twitchings, most commonly due to errors of refraction in children, 
or more continuous spasm, due to some irritation of the fifth or seventh cranial nerves. The 
Orbicularis may be paralyzed, generally associated with paralysis of the other facial muscles. 
Under these circumstances the patient is unable to close the lids, and if he attempts to do so, 
rolls the eyeball upward under the upper lid. The tears overflow from displacement of the lower 
lid, and the conjunctiva and cornea, being constantly exposed and the patient being unable to 
wink, become irritated from dust and foreign bodies. As a result there may be ulceration of 
the cornea, and possibly eventually complete destruction of the eye. In paralysis of the Levator 
palpebrae superioris there is drooping of the upper eyelid {ptosis) and other symptoms of impli- 
cation of the third nerve. The eyelids may be the seat of bruises, wounds, or burns. After 
wounds or burns adhesions of the margins of the lids to each other or adhesion of the lids to 
the globe may take place. The eyelids are sometimes the seat of emphysema after fracture of 
some of the thin bones forming the inner W'all of the orbit. If shortly after such an injury the 
patient blows his nose, air is forced from the nostrils through the lacerated structure into the 1144 
THE ORGANS OF SPECIAL SENSE 
connective tissue of the eyelids, which suddenly swell up and present the peculiar crackling on 
pressure which is characteristic of this affection. 
Foreign bodies frequently get into the conjunctival sac and cause great pain, especially if 
they come in contact with the corneal surface, during the movements of the lid and the eye on 
each other. The conjunctiva is frequently involved in severe injuries of the eyeball, but is seldom 
ruptured alone; the most common form of injury to the conjunctiva alone is from a burn, either 
from fire, strong acids, or lime. In these cases union is liable to take place between the eyelid 
and the eyeball. The conjunctiva is often the seat of inflammation arising from many different 
causes, and the arrangement of the conjunctival vessels should be remembered as affording a 
means of diagnosis between this condition and injection of the sclerotic, which is present in 
inflammation of the deeper structures of the globe. The inflamed conjunctiva is bright red; the 
vessels are large and tortuous, and greatest at the circumference, shading off toward the corneal 
margin; they anastomose freely and form a dense network, and they can be emptied by gentle 
pressure. 
The lachrymal gland is occasionally, though rarely, the seat of inflammation (dacryoadenitis), 
either acute or chronic; it is also sometimes the seat of tumors, benign or malignant, and for these 
may require removal. This may be done by an incision through the skin just below the eyebrow; 
and the gland, being invested with a special capsule of its own, may be isolated and removed 
without opening the general cavity of the orbit. The canaliculi may be obstructed, either as a 
congenital defect or by some foreign body, as an eyelash or a dacryolith, causing the tears to run 
over the cheek. The canaliculi may also become occluded as the result of burns or injury; over- 
flow of tears may in addition result from deviation oj the puncta or from chronic inflammation 
of the lachrymal sac. When there is failure of the lachrymal tubes to drain off the tears and 
the fluid gathers beneath and flows over the lids, the condition is known as epiphora or stilli- 
cidium. This latter condition is set up by some obstruction to the nasal duct frequently occurring 
in tuberculous subjects. In consequence of this the tears and mucus accumulate in the lachrymal 
sac, distending it. Suppuration in the lachrymal sac (dacryocystitis') is sometimes met with; 
this may be the sequel of a chronic inflammation; or may occur after some of the eruptive fevers 
in cases where the lachrymal passages w'ere previously quite healthy. It may lead to lachrymal 
fistula. 
THE EAR (ORGANON AUDITUS). 
The organ of hearing is divisible into three parts-the external ear, the middle 
ear or tympanum, and the internal ear or labyrinth. 
THE EXTERNAL EAR (AURIS EXTERNA). 
The external ear consists of an expanded portion named pinna or auricle, and 
the auditory canal or meatus. The former serves to collect the vibrations of the air 
by which sound is produced; the latter conducts those vibrations to the tympanum. 
The Pinna or Auricle (Auricula) (Fig. 752). 
The pinna or auricle is attached to the side of the head midway between the 
forehead and occiput. " Its level is indicated by horizontal lines extending back- 
ward from the eyebrows above and from the tip of the nose below."1 It is of an 
ovoid form, with its larger end directed upward. Its outer surface is irregularly 
concave, directed slightly forward. The angle which it bears to the head is called 
the cephalo-auricular angle. In some cases this angle is almost absent. In others 
it is nearly a right angle. The pinna of one side may vary in size, shape, and 
angle from the pinna of the other side. The pinna of a woman is apt to be smaller 
than that of a man, and is less often deformed. The outer surface of the pinna 
presents numerous eminences and depressions which result from the foldings of its 
fibrocartilaginous element. To each of these, names have been assigned. Thus 
the external prominent rim of the auricle is called the helix. Another curved prom- 
inence, parallel with and in front of the helix, is called the antihelix; this bifurcates 
above and forms the crura, which encloses a triangular depression, the fossa of the 
antihelix (fossae triangularis [auriculae]). The narrow curved depression between 
1 Arthur Hensman in Henry Morris' Human Anatomy. THE PINNA OR AURICLE 
1145 
the helix and antihelix is called the fossa of the helix or the scaphoid fossa (scapha)} 
the antihelix describes a curve around a deep, capacious cavity, the concha auriculae, 
DARWI N IAN 
TUBERCLE 
FOSSA 
TRIANGULARIS 
CRURA OF 
ANTIHELIX 
SCAPHOID 
FOSSAN 
CRUS OF 
HELIX 
INCISURA 
ANTERIOR 
CYMBA 
CONCHAE' 
TUBERCULUM 
SUPRATRAGlCUM 
■TRAGUS 
EXTERNAL 
AUDITORY 
M EATUS 
INCISURA 
INTERTRAGICA 
POSTERIOR 
AURICULAR 
SULCUS 
Fig. 752.-The right pinna or auricle, viewed from without. (Spalteholz.) 
CAVUM CONCHAE 
which is partially divided into two parts by the crus of the helix, or the commence- 
ment of the helix; the upper part is termed the cymba conchae, the lower part the 
cavum conchae. In front of the 
concha, and projecting backward 
over the meatus, is a small pointed 
eminence, the tragus, so called from 
its being generally covered on its 
under surface with a tuft of hair 
resembling a goat's beard. Oppo- 
site the tragus, and separated from 
it by a deep notch (incisuria inter- 
tragica) is a small tubercle, the 
antitragus. Below this is the lobule 
(lobulus auriculae), composed of 
tough areolar and adipose tissue, 
wanting the firmness and elasticity 
of the rest of the pinna. Some- 
times the lobule does not hang 
freely, but is adherent. Where 
the helix turns downward a small 
tubercle, the tubercle of Darwin (tuberculum auriculae [Darwini]), is frequently seen. 
This tubercle is very evident about the sixth month of foetal life; at this stage 
the human pinna has a close resemblance to that of some of the adult monkeys. 
INSERTION 
OF SUPERIOR 
AURICULAR 
MUSCLE 
INSERTION 
OF ANTERIOR 
AURICULAR- 
MUSCLE 
OBLIQUE- 
AURICULAR 
MUSCLE 
INSERTION OF 
.POSTERIOR 
AURICULAR 
MUSCLE 
TRANSVERSE 
AURICULAR 
MUSCLE 
CARTILAGE 
OF EXTERNAL 
AUDITORY 
MEATUS 
CAUDA 
HELICIN 
Fig. 753.-The cartilages of the right auricle, isolated, with 
the muscles, viewed from the inside. (Spaiteholz.) 1146 
THE OHG ANS OF SPECIAL SENSE 
The cranial surface of the pinna presents elevations which correspond to the 
depressions on its outer surface and after which they are named, e. g., eminentia 
conchae, eminentia fossae triangularis, etc. 
The eminentia conchae and the fossae triangularis are separated by a furrow 
(sulcus antihelicis transversus), which corresponds to the inferior crus of the anti- 
helix, or groove (sulcus cruris helicis), and upon the eminence there is a vertical 
ridge, the pont'culus, which indicates the point of insertion of the Retrahens 
auriculam muscle. 
Structure of the Pinna.-The pinna is composed of a thin plate of yellow 
fibro-cartilage, covered with integument, and connected to the surrounding parts 
by the extrinsic ligaments and muscles, and to the commencement of the external 
auditory canal by fibrous tissue. 
The Integument.-The integument is thin, closely adherent to the cartilage, and 
covered with hairs furnished with sebaceous glands, which are most numerous in 
the concha and scaphoid fossa. The hairs are most numerous and largest on the 
tragus and antitragus. 
The Cartilage of the Pinna (cartilago auriculae) (Fig. 754).-The cartilage of the 
pinna consists of one single piece; it gives form to this part of the ear, and upon its 
surface are found all the eminences 
and depressions above described. 
It does not enter into the construc- 
tion of all parts of the auricle; thus 
it does not form a constituent part 
of the lobule; it is deficient also 
between the lamina of the tragus 
and beginning of the crus helix, the 
notch between (incisura terminalis 
aurw)them being filled up by dense 
fibrous tissue. At the front part of 
the pinna,where the helix bends up- 
ward, is a small projection of car- 
tilage, called the spine of the helix 
(spina helicis), while the lower part 
of the helix is prolonged downward 
as a tail-like process, the cauda 
helicis; this is separated from the 
antihelix by a fissure, the fissura antitragohelicina. The fissures of Santorini are 
usually two in number: one in the substance of the tragus, which partially separates 
the different parts, and one in the cartilage of the meatus. The fissure of the helix 
is a short vertical slit, situated at the forepart of the pinna. Another fissure, the 
fissure of the tragus, is seen upon the anterior surface of the tragus. Anteriorly 
and inferiorly the cartilage of the pinna is continuous with the cartilage of the 
external auditory meatus by a cartilaginous isthmus (isthmus cartilaginis auris). 
Some authors regard the tragus as part of the cartilage of the meatus. The 
cartilage of the pinna is very pliable, elastic, of a yellowish color and belongs to 
that form of cartilage which is known under the name of yellow fibro-cartilage. 
The Ligaments of the Pinna (ligamenti auricularia [FaZ^aZvac]).-The ligaments 
of the pinna consist of two sets: 1. The extrinsic set, or those connecting it to the 
side of the head. 2. The intrinsic set, or those connecting the various parts of its 
cartilage together. 
1 he Extrinsic Ligaments, the most important, are three in number: superior, 
anterior, and posterior. The superior ligament (ligamentum auriculare superius) 
extends from the suprameatal spine to the spine of the helix. The anterior ligament 
(ligamentum auriculare anterius) extends from the spina helicis and tragus to the 
HELIX 
TRIANGULAR 
FOSSA 
SCAPHOID 
. FOSSA 
SPINE OF 
HELIX 
CRUS OF 
HELIX 
LAMINA 
TRAGI 
INCISURA 
FISSURA 
ANTITRAGICO- 
HEL1CINA 
TERMINALIS 
AURIS 
CAUDA OF 
HELIX 
INCISURA 
INTERTRAGICA 
Fig. 754.-The right ear cartilages, isolated, viewed from 
without. (Spalteholz.) 
ANTITRAGUS THE PINNA OH AURICLE 
1147 
root of the zygoma. The posterior ligament {ligamentum auriculare posterius) 
passes from the posterior surface of the concha to the outer surface of the mastoid 
process of the temporal bone. 
'rhe chief Intrinsic Ligaments are: (1) a strong fibrous band, stretching across 
from the tragus to the commencement of the helix, completing the meatus in front, 
and partly encircling the boundary of the concha; and (2) a band which extends 
between the antihelix and the cauda helicis. Other less important bands are 
found on the cranial surface of the pinna. 
The Muscles of the Pinna (Figs. 753 and 755).-The muscles of the pinna consist 
of two sets: 1. The extrinsic, which connect it with the side of the head, moving the 
pinna as a whole-viz., the Attollens, Attrahens, and Retrahens auriculam (p. 369). 
2. The intrinsic, which extend from one part of the auricle to another, viz.: 
Helicis major. 
Helicis minor. 
Tragicus. 
Antitragicus. 
Transversus auriculae 
Obliquus auriculae. 
The Helicis Major (m. helicis major) is a narrow vertical band of muscular 
fibres, situated upon the anterior margin of the helix. It arises, below, from the 
cauda helicis, and is inserted into 
the anterior border of the helix, just 
where it is about to curve backward. 
It is pretty constant in its existence. 
The Helicis Minor (m. helicis minor) 
is an oblique fasciculus which covers 
the crus helicis. 
The Tragicus (m. tragicus) is a 
short, flattened band of muscular 
fibres situated upon the outer surface 
of the tragus, the direction of its 
fibres being vertical. 
The Antitragicus (m. antitragicus) 
arises from the outer part of the anti- 
tragus; its fibres are inserted into the 
cauda helicis and antihelix. This 
muscle is usually very distinct. 
The Transversus Auriculae (m. 
transversus auriculae) is placed on 
the cranial surface of the pinna. It 
consists of scattered fibres, partly 
tendinous and partly muscular, ex- 
tending from the convexity of the 
concha to the prominence corre- 
sponding with the groove of the helix. 
The Obliquus Auriculae (Tod) (m. 
obliquus auriculae) consists of a few 
fibres extending from the upper and back part of the concha to the convexity 
immediately above it. 
The Arteries of the Pinna.-The arteries of the pinna are the posterior auricular 
from the external carotid, the anterior auricular from the temporal and an auric- 
ular branch from the occipital artery. 
The Veins of the Pinna.-The veins of the pinna accompany the corresponding 
arteries. 
The Lymphatics of the Pinna.-The lymphatics enter into the pre-auricular glands 
and the glands upon the Sterno-mastoid muscle at its insertion. 
Fig. 755.-The muscles of the pinna. 1148 
THE ORGANS OF SPECIAL SENSE 
The Nerves of the Pinna.-The nerves of the pinna are: the auricularis magnus, 
from the cervical plexus; the auricular branch of the pneumogastric; the auriculo- 
temporal branch of the inferior maxillary nerve; the occipitalis minor from the 
cervical plexus, and the occipitalis major or internal branch of the posterior 
division of the second cervical nerve. The muscles of the pinna are supplied by 
the facial nerve. 
The External Auditory or External Acoustic Canal or External Auditory 
Meatus (Meatus Acusticus Externus or Meatus 
Auditorius Externus). 
The external auditory or acoustic canal or meatus extends from the bottom 
of the concha to the membrana tympani (Figs. 752, 756, and 757). It is about 
an inch and a half in length if measured from the tragus; from the bottom of 
the concha its length is about an inch. It forms a sort of S-shaped curve, and is 
directed at first inward, forward, and slightly upward (pars externa); it then 
passes inward and backward (pars media), and lastly is carried inward, forward, 
and slightly downward (pars interna). It forms an oval cylindrical canal, the 
greatest diameter being in the vertical direction at the external orifice, but in the 
Cartilage of 
the pinna 
Promont. 
Stapes 
Malleus 
Int. carot. a. 
Membrana 
tympani 
Cartilage of the ext. 
auditor!/ meatus 
Fig. 756.-Transverse section of external auditory meatus and tympanum. Left side. (Gegenbauer.) 
transverse direction at the tympanic end. It presents two constrictions, one 
near the inner end of the cartilaginous portion, and another, the isthmus, in the 
osseous portion, about three-quarters of an inch from the bottom of the concha. 
The membrana tympani (Figs. 756 and 757), which occupies the termination of the 
meatus, is directed obliquely, in consequence of which the floor of the canal is 
longer than the roof, and the anterior wall longer than the posterior. The auditory 
canal is formed partly by cartilage and membrane, partly by bone, and is lined by 
perichondrium and periosteum, which is covered with skin. 
The Cartilaginous Portion (meatus acusticus externus cartilagineus).-The car- 
tilaginous portion is about one-third of an inch (8 mm.) in length; it is formed 
by the cartilage of the pinna, prolonged inward, and firmly attached to a greater 
portion of the circumference of the auditory process of the temporal bone. 'The 
cartilage is deficient at its upper and back part, its place being supplied by fibrous 
membrane. This part of the canal is rendered extremely movable by two or 
three deep fissures, the fissures of Santorini (incisurae cartilaginis meatus acustici 
externi [Santorini]), which extend through the cartilage in a vertical direction. 
It is firmly attached at its lower and front part to the posterior root of the zygoma 
and to the lateral edge of the tympanic portion of the temporal bone. THE EXTERNAL AUDITORY ATE ATES 
1149 
The Osseous Portion (meatus acusticus externus osseus).-The osseous por- 
tion is about two-thirds of an inch (16 mm.) in length, and narrower than the 
cartilaginous portion. It is directed inward and a little forward, forming a slight 
curve in its course, the convexity of which is upward and backward. Its inner 
end, which communicates, in the dry bone, with the cavity of the tympanum, is 
smaller than the outer and sloped, the anterior wall projecting beyond the poste- 
rior about two lines; it is marked, except at its upper part, by a narrow groove, 
the tympanic sulcus (sulcus tympanic us), for the insertion of the membrana tym- 
pani. Its outer edge is dilated and rough in the greater part of its circumference, 
for the attachment of the cartilage of the pinna. Its vertical transverse section 
is oval, the greatest diameter being from above downward. The front and lower 
parts of this canal are formed by a curved plate of bone, which, in the foetus, 
exists as a separate ring (annulus tympanicus), incomplete at its upper part. (See 
Section on Osteology.) 
.FENESTRA OVALIS 
CLOSED BY STAPES 
Fig. 757.-Vertical section through the external auditory meatus and tympanum, passing in front of the 
fenestra ovalis. (Testut.) 
The Skin of the Meatus.-The skin lining the meatus is a prolongation of the 
external skin; it is thin, adheres closely to the cartilaginous and osseous portions 
of the tube, and covers the surface of the membrana tympani, forming a very 
thin outer layer. After maceration the thin pouch of epidermis, when withdrawn, 
preserves the form of the meatus. In the thick subcutaneous tissue of the cartil- 
aginous part of the meatus are numerous ceruminous glands (glandular ceruminosae) 
which secrete the ear-wax. They resemble in structure sweat-glands, and their 
ducts open on the surface of the skin. 
Relations of the Meatus.-Tn front of the osseous part is the glenoid fossa, which 
receives the condyle of the mandible (Fig. 759), which, however, is separated from 
the cartilaginous part by the retromandibular part of the parotid gland. The 
movements of the jaw influence to some extent the lumen of the cartilaginous 
portion. Behind the osseous part are the mastoid air-cells, separated from it 
by a thin layer of bone (Fig. 46). 
The Arteries of the External Meatus.-The arteries supplying the external meatus 
are branches from the posterior auricular, internal maxillary, and superficial 
temporal. THE ORGANS OF SPECIAL SENSE 
1150 
The Veins of the External Meatus.-Veins accompany the corresponding arteries 
and pass to the internal maxillary, temporal, and posterior auricular veins. 
The Lymphatics of the External Meatus.-The lymphatics accompany the veins 
and enter the parotid and posterior auricular lymph-glands. 
The Nerves of the External Meatus.-The nerves are derived from the auriculo- 
temporal branch of the inferior maxillary nerve, the auricularis magnus, and the 
auricular branch of the pneuinogastric. 
Surface Form.-The point of junction of the osseous and cartilaginous portions of the tube 
is an obtuse angle, which projects into the canal at its antero-inferior wall. This produces a 
sort of constriction in this situation, and renders it the narrowest portion of the canal-an impor- 
tant point to be borne in mind in connection with the presence of foreign bodies in the ear. 
The cartilaginous is connected to the bony part by fibrous tissue, which renders the outer part 
of the tube very movable, and therefore by drawing the pinna upward and backward the canal 
is rendered almost straight. At the external orifice are a few short, crisp hairs which serve to 
prevent the entrance of small particles of dust, flies or other insects. In the external auditory 
meatus the secretion of the ceruminous glands serves to catch any small particles which may 
find their way into the canal, and prevent their reaching the membrana tympani, where their 
presence might excite irritation. In young children the meatus is short, the osseous part 
being very deficient, and consisting merely of a bony ring {annulus tympanicus), which supports 
the membrana tympani. In the foetus the osseous part is entirely absent. The shortness of the 
canal in children should be borne in mind in introducing the aural speculum, so that it shall not 
be pushed in too far, at the risk of injuring the membrana tympani; indeed, even in the adult the 
speculum should never be introduced beyond the constriction which marks the junction of the 
osseous and cartilaginous portions. In using this instrument it is advisable that the pinna 
should be drawn upward, backward, and a little outward, so as to render the canal as straight as 
possible, and thus assist the operator in obtaining, by the aid of reflected light, a good view of 
the membrana tympani. Just in front of the membrane is a well-marked depression, situated 
on the floor of the canal and bounded by a somewhat prominent ridge; in this foreign bodies 
may become lodged. By aid of the speculum, combined with traction of the auricle upward 
and backward, the whole of the membrana tympani is rendered visible. It is a pearly-gray mem- 
brane, slightly glistening in the adult, placed obliquely, so as to form with the floor of the meatus 
a very acute angle (about 55 degrees), while with the roof it forms an obtuse angle. At birth it 
is more horizontal-being situated in almost the same plane as the base of the skull. About 
midway between the anterior and posterior margins of the membrane, and extending from the 
centre obliquely upward, is a reddish-yellow streak; this is the handle of the malleus, which is 
inserted into the membrane (Fig. 760). At the upper part of this streak, close to the roof of the 
meatus, a little white rounded prominence is plainly to be seen; this is the processus brevis of 
the malleus, projecting against the membrane. The membrana tympani does not present a 
plane surface; on the contrary, its centre is drawn inward, on account of its connection with the 
handle of the malleus, and thus the external surface is rendered concave. 
THE MIDDLE EAR, DRUM OR TYMPANUM (AURIS MEDIA) 
(Figs. 756, 757, 758, 762). 
The middle ear or tympanum is an irregular cavity, compressed from without 
inward, and is situated within the petrous portion of the temporal bone. It is 
placed above the jugular fossa; the carotid canal lying in front, the mastoid cells 
behind, the external auditory meatus externally, and the labyrinth internally. It is 
lined with mucous membrane, is filled with air, and communicates with the mas- 
toid cells, and with the naso-pharynx by the Eustachian tube. The tympanum is 
traversed by a chain of movable bones, which connect the membrana tympani 
with the labyrinth, and serve to convey the vibrations communicated to the mem- 
brana tympani across the cavity of the tympanum to the external ear. In shape 
it is roughly biconcave, the concave surfaces being placed vertically and forming 
the external and internal walls. The cavity forms an angle of 45 degrees with the 
median plane (Spalteholz). 
The Tympanic Cavity (cavum tympani) (Figs. 762 and 763);--The tympanic 
cavity consists of two parts: the atrium or tympanic cavity proper (Fig. 763), 
opposite the tympanic membrane, and the attic or epitympanic recess or aditus 
ad antrum (recessus epitympanicus) (Figs. 761 and 762), above the level of the THE MIDDLE EAR, DRUM OR TYMPANUM 
1151 
upper part of the membrane; the latter contains the upper half of the malleus 
and the greater part of the incus. The diameter of the tympanic cavity, 
including the attic, measures about f inch (15 mm.) vertically and trans- 
versely. From without inward it measures about | inch (6 mm.) above and £ 
inch (4 mm.) below; opposite the centre of the tympanic membrane it is only 
about inch (2 mm.). It is bounded externally by the membrana tympani and 
meatus; internally, by the outer surface of the internal ear; and communicates 
behind with the mastoid antrum and through it with the mastoid cells; and in 
front with the Eustachian tube and canal for the Tensor tympani. Its roof and 
floor are formed by thin osseous laminae, the one forming the roof being a thin 
plate situated on the anterior surface of the petrous portion of the temporal bone, 
close to its angle of junction with the squamous portion of the same bone. 
The Roof of the Tympanum (paries tegmentalis).-The roof of the tympanum 
is broad, flattened, and formed of a thin plate of bone (tegmen tympani) (Fig. 
762), which separates the cranial and tympanic cavities. It is prolonged back- 
ward so as to roof in the mastoid antrum; it is also carried forward to cover in 
the canal for the Tensor tympani muscle. 
The Floor (paries jugularis) (Fig. 762).-The floor is narrow, and is separated 
by a thin plate of bone (fundus tympani) from the jugular fossa. It frequently 
Chorda tympani. 
Fig. 758.-View of the inner wall of the tympanum (enlarged). 
presents numerous small notches in the bone (cellulae tympanicae). There is one 
small aperture in the floor. It is near the inner wall and is the opening of the 
canaliculus tympanicus, for the transmission of Jacobson's nerve (n. tympanicus). 
On the floor near the posterior wall there is often to be found a slight bony 
projection (prominentia styloideae). 
The Outer Wall (Fig. 757).-The outer wall is formed mainly by the membrana 
tympani, partly by the ring of bone into which this membrane is inserted. 'The 
part formed by the membrana tympanum is called the paries membranaceus. This 
ring of bone is incomplete at its upper part, forming a notch, the notch of Rivinus 
(incisura tympanica [Rivini]) (Fig. 760). The anterior edge of the notch is 
known as the spina tympanica major, the posterior edge as the spina tympanica 
minor. The groove for the reception of the membrana tympani is the sulcus 
tympanicus. Close to the notch are three small apertures: the iter chordae pos- 
terius, the Glaserian fissure, and the iter chordae anterius. 
The iter chordae posterius or the tympanic aperture (canaliculus chordae tympani) 
(Fig. 761) is in the angle of junction between the posterior and external walls of 
the tympanum, immediately behind the membrana tympani and on a level with the 
upper end of the handle of the malleus; it leads into a minute canal, which descends 1152 
THE ORGANS OF SPECIAL SENSE 
in front of the aquaeductus Fallopii, and terminates in the aqueduct near the 
stylomastoid foramen. Through it the chorda tympani nerve enters the tym- 
panum. 
Th? Glaserian or petro-tympanic fissure {fissura petrot ympanica [Glaseri]) (Fig. 
761) opens just above and in front of the ring of bone into which the membrana 
tympani is inserted; in this situation it is a mere slit about a line in length. It 
lodges the long process and anterior ligament of the malleus, and gives passage 
to the tympanic branch of the internal maxillary artery. 
The iter chordae anterius (Fig. 761) is seen at the inner end of the preceding 
fissure; it leads into a canal, the canal of Huguier, which runs parallel with the 
Glaserian fissure. Through it the chorda tympani nerve leaves the tympanum. 
The outer wall bounds the epitympanic recess externally. 
The Internal Wall of the Tympanum {paries labyrinthica} (Figs. 758 and 762).- 
The internal wall of the tympanum is adjacent to the labyrinth, is vertical in direc- 
tion, and looks directly outward. It presents forexamination the following parts: 
Fenestra ovalis. 
Fenestra rotunda. 
Promontory. 
Ridge of the aquaeductus Fallopii. 
Prominence of the external semicircular canal. 
The Fenestra Ovalis, the Oval or the Vestibular Window {fenestra vestibuli} (Fig. 
758) is a reniform opening leading from the tympanum into the vestibule. It 
is situated in the depths of a fossa {fossula fenestrae vestibuli}. Its long diameter 
is directed horizontally, and its convex border is upward. The opening in the 
recent state is occupied by the base of the stapes (Figs. 757 and 763), which is 
connected to the margin of the foramen by an annular ligament. 
The Fenestra Rotunda, the Round or Cochlear Window {fenestra cochleae} (Fig. 
758) is an aperture placed at the bottom of a funnel-shaped depression {fossula 
fenestrae cochleae} leading into the cochlea. It is situated below and rather 
behind the fenestra ovalis, from which it is separated by a rounded elevation, the 
promontory; at its border is a narrow ridge of bone {crista fenestrae cochleae}, and 
it is closed in the recent state by a membrane, the membrane of Scarpa or the 
secondary ear-drum membrane {membrana tympani secundaria}. This membrane 
is concave toward the tympanum, convex toward the cochlea. It consists of 
three layers: the external or mucous, derived from the mucous lining of the 
tympanum; the internal, from the lining membrane of the cochlea; and an inter- 
mediate or fibrous layer. 
The Promontory {promontorium} (Fig. 762) is a rounded hollow prominence, 
formed by the projection outward of the first turn of the cochlea; it is placed 
between the fenestrae, and is furrowed on its surface {sulcus promontorii} for the 
lodgement of the tympanic plexus. A minute spicule of bone frequently connects 
the promontory to the pyramid. 
The Rounded Eminence of the Aquaeductus Fallopii {prominentia canalis facialis} 
(Fig. 762), the prominence of the bony canal in which the facial nerve is contained, 
traverses the inner wall of the tympanum above the fenestra ovalis, and behind 
that opening curves nearly vertically downward along the posterior wall. 
Just above the eminence of the aquaeductus Eallopii the wall is bulged by the 
external semicircular canal {prominentia canalis semicircularis lateralis}. 
The Posterior Wall of the Tympanum {paries mastoidea} (Fig. 762).-The pos- 
terior wall of th? tympanum is wider above than below, and the lower portion of 
the posterior wall contains many tympanic cells. The posterior wall presents for 
examination the-- 
Opening of the antrum. 
Fossa incudis. 
Prominentia styloideae. 
Pyramid. 
Apertura tympanica canaliculi chordae. THE MIDDLE EAR, DRUM OR TYMPANUM 
1153 
The Opening of the Antrum is a large irregular aperture, which extends back- 
ward from the epitympanic recess and leads into a considerable air space, the 
mastoid antrum (antrum tympanicum), which is the entrance to the mastoid cells 
(p. 87). The antrum communicates with large irregular cavities contained 
in the interior of the mastoid process, the mastoid air-cells. These cavities vary 
considerably in number, size, and form; they are lined by mucous membrane 
continuous with that lining the cavity of the tympanum. 
The Fossa Incudis (Fig. 762) is placed in the posterior and inferior part of the 
epitympanic recess. It lodges the short process of the incus. 
The Prominentia Styloideae is sometimes seen below the apertura tympanica 
canaliculi chordae. It is a prominence produced by a prolongation of the styloid 
process. 
The Pyramid (eminentia pyramidalis^Y'x^. 758) is a conical eminence situated 
immediately behind the fenestra ovalis, and in front of the vertical portion of the 
eminence above described; it is hollow in the interior, and contains the Stapedius 
muscle; its summit projects forward toward the fenestra ovalis, and presents a 
small aperture which transmits the tendon of the muscle. The cavity in the 
pyramid is prolonged into a minute canal, which communicates with the aquae- 
ductus Fallopii and transmits the nerve which supplies the Stapedius. 
The Apertura Tympanica Canaliculi Chordae is just back of the posterior edge of the 
tympanic membrane, nearly level with the superior end of the manubrium mallei. 
The Anterior Wall of the Tympanum (paries carotica).-The anterior wall of 
the tympanum is bony on its lower portion. Its upper part is the tympanic 
opening of the Eustachian tube. The long anterior wall contains tympanic 
cells. The anterior wall is wider above than below; it corresponds with the 
carotid canal, from which it is separated by a thin plate of bone (Fig. 762), per- 
forated by the canaliculi caroticotympanici, which transmit the tympanic branch 
of the internal carotid artery and the carotico-tympanic nerves. It presents for 
examination the- 
Canal for the Tensor tympani. 
The processus cochleariformis. 
Orifice of the Eustachian tube. 
The orifice of the canal for the Tensor tympani and the orifice of the Eustachian 
tube are situated at the upper part of the anterior wall, being incompletely sepa- 
rated from each other by a thin, delicate, horizontal plate of bone, the processus 
cochleariformis (septum canalis musculotubarii) (Figs. 49 and 758). The canalis 
musculotubarius is divided by this long process into the canal for the Tensor 
tympani and the canal for the Eustachian tube. These canals run from the 
tympanum forward, inward, and a little downward, to the retiring angle between 
the squamous and petrous portions of the temporal bone. 
The Canal for the Tensor Tympani (semicanalis m. tensoris tympani) (Figs. 49, 
758, and 762) is the superior and the smaller of the two; it is rounded and lies 
beneath the forward prolongation of the tegmen tympani. It extends on to the 
inner wall of the tympanum and ends immediately above the fenestra ovalis. The 
processus cochleariformis passes backward below this part of the canal, forming 
its outer wall and floor; it expands above the anterior extremity of the fenestra 
ovalis and terminates by curving outward so as to form a pulley over which the 
tendon passes. The bony wall of this canal is incomplete, and the osseous vacancy 
is filled by tough connective tissue. 
The Eustachian Tube or Ear Trumpet (tuba auditiva [Eustachii]) (Figs. 49, 
758, and 759) is the channel through which the tympanum communicates with 
the pharynx. Its length is an inch and a half (36 mm.), and its direction 
downward, inward, and forward, forming an angle of about 45 degrees with 
the sagittal plane and one of from 30 to 40 degrees with the horizontal plane. 1154 
THE ORGANS OF SPECIAL SENSE 
The canal for the Eustachian tube (semicanalis tubae auditivae) (Fig. 759) is formed 
partly of bone, partly of cartilage and fibrous tissue. 
The Osseous Portion (pars ossea tubae auditivae or semicanalis tubae auditivae) 
is about half an inch in length. It is the outer portion of the tube. It commences 
in the anterior wall of the tympanum, below the processus cochleariformis (ostium 
tympanicum tubae auditivae), and, gradually narrowing, terminates at the angle 
of junction of the petrous and squamous portions of the temporal bone, its 
extremity presenting a jagged margin which serves for the attachment of the 
cartilaginous portion. The roof of the osseous portion is the tegmen tympani. 
The inner wall is formed in part by the inner wall of the tympanum and in part 
by the canal for the Tensor tympani muscle. The outer wall is the tympanic 
portion of the temporal bone. The floor is a groove which near the tympanum 
contains the openings of air-cells (cellulae pneumatici tubarii). 
TENSOR TYMPANI 
INCUS 
MEMBRANA 
TYMPANI 
STYLOID 
PROCESS 
PHARYNGEAL OPEN 
ING OF TUBE 
Fig. 759.-Eustachian tube, laid open by a cut in its long axis. (Testut.) 
The Cartilaginous Portion (pars cartdaginea tubae auditivae), about an inch in 
length, is formed of a triangular plate of elastic fl bro-cartilage (cartilage tubae 
auditivae), the apex of which is attached to the margin of the inner extremity of 
the osseous canal, while its base lies directly under the mucous membrane of 
the naso-pharynx, where it forms an elevation or cushion above and behind the 
pharyngeal orifice of the tube. The upper edge of the cartilage is curled upon 
itself, being bent outward so as to present on transverse section the appearance of 
a hook (lamina lateralis); a groove or furrow is thus produced, which opens below 
and externally, and this part of the canal is completed by fibrous membrane. On 
transverse section the cartilage exhibits the laminae which above are continuous 
with each other: the hard, thick lamina medialis and the thin and hooked lamina 
lateralis. The cartilage of the Eustachian tube, with a hood plate of cartilage, 
forms the posterior portion of the inner wall (the lamina medialis). The cartilage 
is fixed to the base of the skull, and lies in a groove (sulcus tubae auditivae) 
between the petrous-temporal and the greater wing of the sphenoid; this groove 
ends opposite the middle of the internal pterygoid plate, in a projection, the THE MIDDLE EAR, DRUM OR TYMPANUM 
1155 
processus tubarius. At the pharyngeal orifice the entire wall of the tube is cartil- 
aginous, but the breadth of the cartilage progressively lessens as the isthmus is 
approached. Here and there the cartilage is deficient or pieces lie separate from 
the rest, the spaces between the islands being occupied by fibrous tissue. The Ten- 
sor palati muscle is placed to the outer side of the tube. The fibres of the muscle 
which take origin from the lamina lateralis are known as the dilator tubae muscle of 
Rudinger. The Tensor palati muscle and the mucous membrane of the pharynx lie to 
the inner side of the tube. The under and outer portion of the canal is completed 
by the membranous part (lamina membranacea), which is a strong fibrous mem- 
brane, passing between the two margins of the cartilage. It is thin above, but thick 
below, and the thick portion is called the fascia salpingopharyngea of Troltsch, 
and from it arise some fibres of the Tensor palati (m. salpingopharyngeus}. The 
cartilaginous and bony portions of the tube are not in the same plane, the former 
POSTERIOR TYMPANO- 
MALLEOLAR FOLD 
FLACCID PORTION OF 
MEMBRANA TYMPANI 
POSTERIOR 
TYMPANIC 
SPINE 
EXTERNAL 
AUDITORY 
MEATUS 
MALLEOLAR 
PROMINENCE 
MARGIN OF 
MEMBRANA 
TYMPANI 
OR LIMBUS 
NOTCH OF 
RIVINUS 
ANTERIOR 
TYMPANO- 
MALLEOLAR 
FOLD 
HANDLE OF 
MALLEOLUS 
SEEN THROUGH 
MEMBRANE 
■UMBO 
TENSE PORTION 
OF MEMBRANA 
TYMPANI 
Fig. 760.-The right membrana tympani, viewed from the outside, from in front, and from below. (Spalteholz.) 
inclining downward a little more than the latter. They join each other at a large 
obtuse angle, open below. The diameter of the canal is not uniform throughout, 
being greatest at the pharyngeal orifice and least at the junction of the bony and 
cartilaginous portions, where it is named the isthmus (isthmus tubae auditivaey, 
it again expands somewhat as it approaches the tympanic cavity. The 
position and relations of the pharyngeal orifice (ostium pharyngeum tubae 
auditivae} are described with the anatomy of the naso-pharynx. Through this 
canal the mucous membrane of the pharynx is continuous with that which lines 
the tympanum. The mucous membrane is covered with ciliated epithelium and 
is thin in the osseous portion, while in the cartilaginous portion it contains many 
mucous glands and near the pharyngeal orifice a considerable amount of adenoid 
tissue, which has been named by Gerlach the tube-tonsil. The tube is opened 
during deglutition by the Salpingo-pharyngeus and Dilator tubae muscles. 
The Drumhead or Membrana Tympani (Figs. 757, 759, 760, and 761).-The 
membrana tympani or drumhead separates the cavity of the tympanum from THE ORGANS OF SPECIAL SENSE 
1156 
the bottom of the external meatus. It is a thin, semi-transparent membrane, 
nearly oval in form, somewhat broader above than below, and directed very 
obliquely downward and inward, so as to form an angle of about 55 degrees 
with the floor of the meatus (Fig. 757). The antero-inferior portion is, there- 
fore, placed at the greatest distance from the external orifice of the meatus. It 
is asserted that in musicians the membrana tympani is placed more nearly per- 
pendicular, and that in deaf-mutes and cretins it is placed more obliquely than 
the usual 55 degrees. In a newborn child the membrana tympani is almost hori- 
zontal. The greatest diameter of the membrana tympani is from 9 to 10 mm.; 
its least diameter is from 8 to 9 mm.1 The greater part of its circumference (limbus 
membranae tympanae} is thickened to form an annular ring (annulus fibrocartil- 
agineus}, which is fixed in a groove, the sulcus tympanicus, at the inner extremity 
SUPERIOR LIGAMENT 
OF MALLEOLUS 
EPITYM PAN IC 
RECESS 
ARTICULAR SURFACE 
'FOR BODY OF INCUS 
NECK OF 
malleus' 
ANTERIOR LIGAMENT 
AND ANTERIOR 
PROCESS OF' 
MALLEOLUS 
FLACCID PORTION OF 
MEMBRANA TYMPANI 
INSERTION 
OF TENSOR 
TYMPANI- 
MUSCLE, 
POSTERIOR 
TYMPANIC 
SPINE 
TYMPANIC 
ORIFICE 
OF CANAL 
FOR CHORDA 
TYMPAN I 
NERVE 
GLASStrtlAN 
FISSURE* 
EUSTACHIAN 
TUBE 
TENSE PORTION OF 
MEMBRANA TYMPANI 
Fig. 761.-The right membrana tympani with the hammer and the chorda tympani, viewed from within, 
from behind, and from above. (Spalteholz.) 
of the external meatus. This sulcus is deficient superiorly at the incisure or notch 
of Rivinus (incisura tympanica [Rivini]} (Fig. 760). From the extremities of the 
notch (spinae tympanicae} two folds pass and converge to the short process of the 
malleus (Fig. 760). One is known as the anterior tympanomalleolar fold or ligament 
(plica membrana tympani anterior}. The other is known as the posterior tympano- 
malleolar fold or ligament (plica membrana tympani posterior}. These are not to 
be confused with the anterior and posterior malleolar folds (p. 1162). The small, 
somew'hat triangular part of the membrane situated above these folds is lax and 
thin, and is named the flaccid portion or the membrana flaccida of Shrapnell (Figs. 
760 and 761). In it a small orifice is sometimes seen, which is of artificial and 
pathological formation. The larger lower portion of the drum membrane is 
stretched tightly, and is called the tense portion or pars tensa (Figs. 760 and 761). 
1 Prof. Cunningham's Text-book of Anatomy. THE MIDDLE EAR, DRUM OR TYMPANUM 
1157 
The handle of the malleus is firmly attached to the inner aspect of the mem- 
brana tympani as far as its centre (Fig. 761). It draws the central part of the 
membrane inward and makes its outer aspect concave. The most depressed part 
of the concavity is called the umbo or navel (umbo membranae tympanae) (Fig. 760). 
The walls of the umbo are convex outward. 
On the outer surface of the drum membrane a light stripe (stria malleolaris) is 
seen. It runs from in front and above downward and backward, and is produced 
by the handle of the malleus, showing through the membrane (Fig. 760). 
Structure.-This membrane is composed of three layers: an external (cuticular), 
a middle (fibrous), and an internal (mucous). The cuticular lining (stratum cuta- 
neum) is derived from the integument lining the meatus. The fibrous or 
middle layer (membrana propria) consists of two strata: an external, of radiating 
fibres (stratum radiatum), which diverge from the handle of the malleus, and an 
JUNCTION BETWEEN MAS- 
TOID ANTRUM AND 
EPITYMPANIC RECESS 
TEGM EN 
TYMPAN I 
EPITYM PANIC 
RECESS 
PROMINENCE OF EXTERNAL 
SEMICIRCULAR CANAL 
PROMINENCE OF AQUEDUCT 
OF FALLOPIUS 
TENDON OF 
STAPEDIUS MUSCLE 
PLICA 
STAPEDIUS 
PROCESSUS 
COCH LEARI FORMIS 
TENSOR TYMPANI 
muscle (cut through) 
WALL OF 
LABYRINTH 
FOSSA 
INCUDIS 
POSTERIOR 
SINUS 
PYRAM IDAL 
EMI N ENCE 
TYM PAN IC 
SINUS 
Fig. 762.-The medial wall and part of the posterior and anterior walls of the right tympanic cavity, lateral 
view. (Spalteholz.) 
FOSSULA OF 
FENESTRA ROTUNDA 
JUGULAR 
WALL 
TYMPANIC 
PLEXUS 
internal, of circular fibres (stratum, circulars), which are plentiful around the cir- 
cumference, but sparse and scattered near the centre of the membrane. Branched 
or dendritic fibres, as pointed out by Gruber, are also present, especially in the 
posterior half of the membrane. Both muscular layers are connected to the 
annulus fibrocartilagineus, and both are absent in the pars flaccida. The inner 
or epithelial layer is mucous membrane (stratum mucosum), which is a portion 
of the mucous membrane of the drum cavity. 
The Arteries are derived from the deep auricular branch of the internal maxil- 
lary, which ramifies beneath the cuticular layer and from the stylo-mastoid branch 
of the posterior auricular and tympanic branch of the internal maxillary, which 
are distributed on the mucous surface. The arteries of the cutaneous set anas- 
tomose with the arteries of the mucous set by minute branches which penetrate 
the drum membrane near its margin. The superficial veins open into the external 
jugular; those on the mucous surface drain themselves partly into the lateral 
sinus and veins of the dura mater and partly into a plexus on the Eustachian tube. 1158 
T.HE ORGANS OF SPECIAL SENSE 
The outer surface of the drum membrane receives its nervous supply from the 
auriculo-temporal branch of the inferior maxillary and the auricular branch of 
the vagus. The inner surface is supplied by the tympanic branch of the glosso- 
pharyngeal. 
There are two sets of lymphatics, the cutaneous and mucous, which freely 
communicate. The spaces between the dendritic fibres of Gruber are lymph- 
spaces (Kessel). 
The tympanum contains in its upper part a chain of movable bones, three in 
number, the malleus, incus, and stapes. The first is attached to the membrana 
tympani, the last to the fenestra ovalis. The 
incus is placed between the two, and is con- 
nected to both by delicate articulations. 
The Malleus or Hammer (Fig. 764).-The 
malleus or hammer, so named from its fancied 
resemblance to a hammer, is placed farthest in 
front and outward. It consists of a head, neck, 
and three processes-the handle or manubrium, 
the processus gracilis, and the processus brevis. 
The Head (capitulum mallei').-The head is 
the large upper extremity of the bone, and is 
situated in the epitympanic recess (Fig. 761). 
It is oval in shape, and articulates posteriorly 
with the incus, being free in the rest of its ex- 
tent. The facet for articulation with the incus 
is covered with cartilage, is constricted near 
the middle, and is divided by a ridge into an 
upper, larger, and a lower, lesser part, which 
form nearly a right angle with each other. Op- 
posite the constriction the lower margin of the 
facet projects in the form of a process, the 
cog-tooth or spur of the malleus. On the back 
of the head below the spur is a crest (crista 
mallei), to which the posterior ligament of the malleus is attached. 
The Neck (collum mallei).-The neck is the narrow contracted part just beneath 
the head; and below this is a prominence, to which the various processes are 
attached. The outer surface of the neck faces the membrana flaccida. The 
chorda tympani nerve crosses the inner surface (Fig. 761). 
The Handle or Manubrium (manubrium mallei).- -The manubrium is a vertical 
process of bone, which is connected by its outer margin with the fibrous layer of 
the membrana tympani, its entire length being fastened to the fibrous layer of 
the drum membrane by its own periosteum and by a layer of cartilage (Gruber) 
(Figs. 761 and 763). It is directed downward, inward, and backward; it decreases 
in size toward its extremity, where it is curved slightly forward, and is flattened 
from within outward. The handle forms a variable angle with the head of the 
hammer. It averages about 130 degrees, but is always greater in the right ear 
than in the left. It forms an angle with the horizontal, averaging on the right 
side 50 degrees and on the left side 45 degrees (Spalteholz). Internally the 
handle is covered by the mucous membrane of the tympanum. On the inner 
side, near its upper end, is a slight projection, into which the tendon of the 
Tensor tympani is inserted (Fig. 761). 
The Processus Gracilis or Long Process (processus anterior [Folii]).-The pro- 
cessus gracilis is a long and very delicate process, which passes from the front of 
The Ossicles of the Tympanum (Ossicula Auditus) (Fig. 763). 
Fig. 763.-Chain of ossicles and their liga- 
ments, seen from the front in a vertical, trans- 
verse section of the tympanum. (Testut.) THE OSSICLES OF THE TYMPANUM 
1159 
the neck forward and outward to the Glaserian fissure, to which it is connected 
by ligamentous fibres. In the foetus this is the longest process of the malleus, and 
is in direct continuity with the cartilage of Meckel. 
The Processus Brevis (processus lateralis).-The processus brevis is a slight 
conical projection, which springs from the root of the manubrium; it is directed 
outward, and is attached to the upper part of the tympanic membrane by cartilage 
and to the margins of the notch of Rivinus by the two malleolar folds. 
a 
b 
HEAD- 
AURICULAR 
. SURFACE 
*FOR BODY 
OF INCUS 
TOOTH 
OR CQG' 
INSERTION OF 
EXTERNAL 
LIGAMENT 
OF MALLEUS 
NECK 
INSERTION 
OF TENSOR 
TYM PANI 
MUSCLE 
NECK- 
SHORT 
PROCESS 
LONG 
PROCESS 
SHORT 
PROCESS 
MANUBRIUM 
r MANUBRIUM 
Fig. 764.-The right malleus: a, viewed from in front; b, viewed from behind. (Spalteholz.) 
The Incus or Anvil (Fig. 765).-The incus or anvil has received its name from 
its supposed resemblance to an anvil, but it is more like a bicuspid tooth with two 
roots, which differ in length, and are widely separated from each other. It con- 
sists of a body and two processes. The body and the short process are placed in 
the epitympanic recess (Fig. 763). 
The Body (corpus incudis).-The body is somewhat quadrilateral, but compressed 
laterally. On its anterior surface is a deeply concavo-convex facet, which articu- 
lates with the head of the malleus, and the lower part is hollowed for the spur of the 
malleus. In the fresh state the articular surface is covered with cartilage and the 
joint is lined with synovial membrane. 
a 
b 
SHORT 
PROCESS 
ARTICULAR SURFACE 
FOR HEAD OF MALLEUS 
ARTICULAR 
SURFACE FOR 
HEAD OF 
MALLEUS 
SHORT 
"PROCESS 
TOOTH 
OR COG 
TOOTH_ 
OR COG' 
LONG 
PROCESS' 
LONG 
PROCESS' 
LENTICULAR 
PROCESS 
Fig. 765.-The right incus: a, lateral view; b, medial and front view. (Spalteholz.) 
Processes.-The two processes diverge from one another at an angle of from 
90 to 100 degrees. 
The Short Process (crus breve), somewhat conical in shape, projects nearly 
horizontally backward, and articulates with a depression, the incus fossa (fossa 
incudis), in the lower and back part of the epitympanic recess. 
The Long Process (crus longum), longer and more slender than the preceding, 
descends nearly vertically behind and parallel to the handle of the malleus, and, THE OHG ANS OF SPECIAL SENSE 
1160 
bending inward, terminates in a rounded globular projection, the os orbiculare or 
lenticular process (processus lenticularis), which is tipped with cartilage, and articu- 
lates with the head of the stapes. In the foetus the os orbiculare exists as a separate 
bone. 
The Stapes or Stirrup (Fig. 766).-The stapes or stirrup, so called from its 
close resemblance to a stirrup, consists of a head, neck, two crura, and a base. 
The Head (capitulum stapedis).-The head presents a depression, tipped with 
cartilage, which articulates with the os orbiculare. 
The Neck.-The neck, the constricted part of the bone succeeding the head, 
receives the insertion of the Stapedius muscle. 
The Crura.-The two crura (crus anterius and crus posterius) diverge from the 
neck and are connected at their extremities by a flattened, oval-shaped plate, the 
foot-plate or base (basis stapedis), which forms the foot-plate of the stirrup and 
is fixed to the margin of the fenestra ovalis by ligamentous fibres. The foot- 
plate almost fills the oval window (Fig. 757. Of the two crura, the anterior is 
shorter and less curved than the posterior. In a recent specimen a membrane will 
be observed filling the space between the 
crura and the foot-plate. This mem- 
brane is connective tissue and is called 
the membrana obturatoria stapedis. The 
stirrup lies practically horizontal. 
Articulations of the Ossicles of the Tym- 
panum (articulationes ossiculorum audi- 
tus) (Fig. 763).-These small bones are 
connected with each other and with the 
walls of the tympanum by ligaments, and 
are moved by small muscles. There is an 
articulation between the head of the hammer and the body of the anvil; one 
between the os orbiculare of the anvil and the head of the stirrup; and there is a 
syndesmosis between the margins of the oval window and the base of the stirrup. 
The bones are fastened in the tympanum, the handle of the hammer being 
fastened in the drum membrane and the base of the stirrup to the oval window. 
The articular surfaces of the malleus and incus and the orbicular process of the 
incus and head of the stapes are covered with cartilage, connected together by 
delicate capsular ligaments and lined by synovial membrane. 
Ligaments Connecting the Ossicula with the Walls of the Tympanum (ligamenta 
ossiculorum auditus).-The malleus is fastened to the wall of the tympanum by 
three ligaments: the anterior, superior, and external ligaments. 
The Anterior Ligament of the Malleus (lipamentum mallei anterius) consists of 
two parts, the band of Meckel and the anterior ligament of Helmholtz. 
The band of Meckel is attached to the base of the processus gracilis and passes 
through the Glaserian fissure to reach the spine of the sphenoid. It was formerly 
described by Sommering as a muscle, and it was called the laxator tympani 
muscle. It is now, however, believed by most observers to consist of ligamentous 
fibres only. 
The anterior ligament of Helmholtz extends from the anterior margin of the 
notch of Rivinus to the anterior portion of the malleus, just above the processus 
gracilis. 
The Superior Ligament of the Malleus (ligamentum mallei superius) is a delicate 
round bundle of fibres which descends perpendicularly from the roof of the epi- 
tympanic recess to the head of the malleus. It is sometimes called the suspensory 
ligament. 
The External Ligament of the Malleus (ligamentum mallei laterale) is a triangular 
plane of fibres passing from the posterior part of the notch in the tympanic ring 
a 
HEAD 
GROOVE FOR 
OBTURATOR 
' MEMBRANE 
OF STAPES 
b 
ANTERIOR 
CRUS 
POSTERIOR 
CRUS 
BASE OF 
STAPES 
BASE OF STAPES 
Fig. 766.-The right stirrup: a, viewed from above; 
b\ medial vein. (Spalteholz.) THE OSSICLES OE THE TYMPANUM 
1161 
(incisura Rivini) to the crest of the malleus. The posterior portion of the external 
ligament is sometimes called the posterior ligament of Helmholtz (ligamentum 
mallei posterius [Helmholtzi]). The malleus rotates around an axis composed of 
the external and anterior ligaments, hence these two ligaments constitute what 
Helmholtz called the axis ligament of the malleus. 
The incus is fastened to the wall of the tympanum by two ligaments, the poste- 
rior and the superior. 
The Posterior Ligament of the Incus (ligamentum incudis posterius) is a short, 
thick, ligamentous band which connects the extremity of the short process of the 
incus to the posterior and lower part of the epitympanic recess, near the margin 
of the opening of the mastoid cells. 
A Superior Ligament of the Incus (ligamentum incudis superius) has been 
described by Arnold, but it is little more than a fold of mucous membrane. 
The inner surface and the circumference of the base of the stapes are covered with 
hyaline cartilage, and the annular ligament of the stapes (ligamentum annulare baseos 
stapedis) connects the circumference of the base to the margin of the fenestra ovalis. 
The Muscles of the Tympanum (m. ossiculorum auditus).-The muscles of the 
tympanum are two: 
Tensor tympani. Stapedius. 
The Tensor Tympani (m. tensor tympani) (Fig. 762), the larger, is contained in 
the bony canal above the osseous portion of the Eustachian tube, from which it 
is separated by the processus cochleariformis. It arises from the under surface of 
the petrous bone, from the cartilaginous portion of the Eustachian tube, and from 
the osseous canal in which it is contained. Passing backward through the canal, 
it terminates in a slender tendon which enters the tympanum and makes a sharp 
bend outward around the extremity of the processus cochleariformis, and is 
inserted into the handle of the malleus near its root. Its nerve-supply is from 
the motor root of the fifth cranial nerve by way of the otic ganglion. 
The Stapedius (m. stapedius) (Fig. 762) arises from the side of a conical cavity 
hollowed out of the interior of the pyramid; its tendon emerges from the orifice 
at the apex of the pyramid, and, passing forward, is inserted into the neck of the 
stapes. Its surface is aponeurotic, its interior fleshy, and its tendon occasionally 
contains a slender bony spine, which is constant in some mammalia. It is 
supplied by the tympanic branch of the facial nerve. 
Actions.-The Tensor tympani draws the handle of the malleus inward and 
thus heightens the tension of the drum membrane. It also causes slight rotation 
of the bone around its long axis. When the Stapedius contracts it draws the 
head of the stirrup backward, and in consequence the anterior end of the foot- 
plate passes outward toward the tympanum, and the posterior end inward toward 
the vestibule, and the annular ligament is made tense. 
Movements of the Ossicles of the Tympanum.-The chain of bones is a lever-like 
arrangement, by means of which the vibrations of the membrana tympani are 
transferred to the membrane covering the oval window, and from this to the peri- 
lymph in the labyrinth. When the drum membrane moves inward, the handle 
of the malleus moves with it. The movement of the malleus moves the incus, and 
the movement of the incus drives the foot of the stapes toward the labyrinth. 
When the handle of the malleus moves inward, the spur on the head becomes 
locked with the body of the incus. During outward movement it is unlocked. 
The ordinary outward movement of the drum membrane causes the above- 
described movements to be reversed. When there is overforcible outward move- 
ment the incus does not go outward quite as far as the malleus, but slides at the 
joint between the malleus and incus. This reluctance of the incus saves the foot 
of the stapes from being pulled away from the oval window. 1162 
THE ORGANS OF SPECIAL SENSE 
The Mucous Membrane of the Tympanum (tunica mucosa tympanica).-The 
mucous membrane of the tympanum is continuous with the mucous membrane 
of the naso-pharynx through the Eustachian tube, and is firmly united to the 
periosteum. It invests the ossicula, and the muscles and nerves contained in the 
tympanic cavity; forms the internal layer of the membrana tympani, and the outer 
layer of the membrana tympani secundaria, and is reflected into the mastoid 
antrum and air-cells, which it lines throughout. It forms several vascular folds 
(plicae), which extend from the walls of the tympanum to the ossicles. In these 
folds the ossicles are enveloped. 
The anterior malleolar fold (plica malleolaris anterior) comes off from the mem- 
brana tympani between the anterior edge of the notch of Rivinis and the handle 
of the malleus, envelops the processus gracilis of the malleus, the anterior liga- 
ment of the malleus, and the anterior portion of the chorda tympani nerve, and 
terminates in a free concave edge (Spalteholz). The posterior malleolar fold (plica 
malleolaris posterior) is the larger of the two. It comes off from the margin of the 
notch of Rivinis, envelops the external ligament of the malleus, the posterior part 
of the chorda tympani nerve, is attached to the handle of the malleus, and ends 
in a free concave margin (Spalteholz). The fold of the incus (plica incudis) takes 
origin from the roof of the epitympanic recess and passes to the body and short 
process of the incus; and a similar fold passes from the head of the malleus to the 
anterior wall of the epitympanic recess. The entire stapes, with its obturator 
membrane, is enwrapped by the fold of the stapes (plica stapedis). This fold also 
ensheaths the tendon of the stapedius muscle and often reaches to the posterior 
wall of the cavity of the tympanum. The mucous membrane over the round 
window forms the membrana tympani secundaria. These folds separate off pouch- 
like cavities, and give the interior of the tympanum a somewhat honey-comb 
appearance. One of these pouches is well marked-viz., the pouch of Prussak, 
which lies between the neck of the malleus and the membrana flaccida. 
The inferior external pouch of the tympanum or the pouch of Prussak (recessus 
membranae tympani superior) is between the flaccid portion of the membrana 
tympani, the external ligament of the malleus, and the neck of the mal- 
leus. The anterior and posterior malleolar folds with the tympanic membrane 
form two pouches. These are the anterior and posterior pouches or recesses of 
Trbltsch (recessus membranae tympani, anterior and posterior). The anterior pouch 
is blind above and has a slit-like opening below. The posterior pouch is con- 
tinued into the blind superior pouch of the drum membrane. In the tympanum 
this membrane is pale, thin, slightly vascular, and covered for the most part with 
columnar ciliated epithelium, but that covering the pyramid, ossicula, and mem- 
brana tympani possesses a flattened, non-ciliated epithelium. In the antrum and 
mastoid cells its epithelium is also non-ciliated. In the osseous portion of the 
Eustachian tube the membrane is thin; but in the cartilaginous portion it is very 
thick, highly vascular, covered with ciliated epithelium, and provided with numer- 
ous mucous glands. 
The Arteries of the Tympanum.-The arteries supplying the tympanum are six 
in number. Two of them are larger than the rest-viz., the tympanic branch of 
the internal maxillary, which enters by way of the Glaserian fissure and supplies 
the membrana tympani; and the stylo-mastoid branch of the posterior auricular, 
which passes through the stylo-mastoid foramen and the aqueduct of Fallopius, 
and supplies the inner wall and floor of the tympanum, the mastoid cells, and 
antrum and the Stapedius muscle. This vessel anastomoses around the drum 
membrane with the ^tympanic. The middle meningeal sends a small branch to 
the Tensor tympani muscle near its origin. The petrosal branch of the middle 
meningeal enters the tympanum by way of the hiatus Fallopii. Minute branches 
from the posterior branch of the middle meningeal pass through the petro- THE INTERNAL EAR OR LABYRINTH 
1163 
squamous fissure and are distributed to the antrum and epitympanic recess 
(Cunningham). Two tympanic branches come oft' from the internal carotid 
artery in its course through the carotid canal. A branch from the ascending 
pharyngeal and another from the Vidian, accompany the Eustachian tube. The 
two tympanic branches from the internal carotid are given off in the carotid canal 
and perforate the thin anterior wall of the tympanum. 
The Veins of the Tympanum.-The veins of the tympanum terminate in the 
pterygoid plexus, the middle meningeal vein, and the superior petrosal sinus. 
The Nerves of the Tympanum.-The nerves of the tympanum constitute the 
tympanic plexus (plexus tympanicus [Jacobsonty, which ramifies upon the surface 
of the promontory (Fig. 762). The plexus is formed by (1) the tympanic branch of 
the glosso-pharyngeal; (2) the small deep petrosal nerve; (3) the small super- 
ficial petrosal nerve; and (4) a branch which joins the great superficial petrosal. 
The Tympanic Branch of the Glosso-pharyngeal or Jacobson's Nerve (n. tympan- 
icus) enters the tympanum by an aperture in its floor close to the inner wall and 
divides into branches, which ramify on the promontory and enter into the forma- 
tion of the plexus. The small deep petrosal nerve (n. petrosus profundus), from 
the carotid plexus of the sympathetic, passes through the wall of the carotid canal, 
and joins the branches of Jacobson's nerve. The branch to the great superficial 
petrosal passes through an opening on the inner wall of the tympanum in front 
of the fenestra ovalis. The small superficial petrosal nerve (n. petrosus super- 
ficialis minor), derived from the otic ganglion, passes through a foramen in the 
middle fossa of the base of the skull (sometimes through the foramen ovale), 
passes backward and enters the petrous bone through a small aperture, situ- 
ated external to the hiatus Fallopii on the anterior surface of this bone; it then 
courses downward through the bone, and, passing by the gangliform enlargement 
of the facial nerve, receives a connecting filament from it (Fig. 676) and enters the 
tympanic cavity, where it communicates with Jacobson's nerve, and assists in 
forming the tympanic plexus. 
The branches of distribution of the tympanic plexus are distributed to the 
mucous membrane of the tympanum; one special branch passing to the fenestra 
ovalis, another to the fenestra rotunda, and a third to the Eustachian tube. The 
small superficial petrosal may be looked upon as a branch from the plexus to the 
otic ganglion. 
In addition to the tympanic plexus there are the nerves supplying the muscles. 
The Tensor tympani is supplied by a branch from the third division of the fifth 
through the otic ganglion, and the Stapedius by the tympanic branch of the facial. 
The chorda tympani (Figs. 758 and 761) crosses the tympanic cavity. It is given 
off from the facial as it passes vertically downward at the back of the tympanum, 
about a quarter of an inch before its exit from the stylo-mastoid foramen. It passes 
from below upward and forward in a distinct canal, and enters the cavity of the 
tympanum through an aperture, iter chordae posterius, already described (p. 1151), 
and becomes invested with mucous membrane. It passes forward, through the 
cavity of the tympanum, crossing internal to the membrana tympani and over 
the handle of the malleus to the anterior inferior angle of the tympanum, and 
emerges from that cavity through the iter chordae anterius or canal of Huguier 
(p. 1152). It is invested by the fold of mucous membrane already mentioned, and 
therefore lies between the mucous and fibrous layers of the membrana tympani. 
THE INTERNAL EAR OR LABYRINTH (AURIS INTERNA). 
The internal ear is the essential part of the organ of hearing, receiving the 
ultimate distribution of the auditory nerve. It is called the labyrinth, from the 1164 
THE ORGANS OF SPECIAL SENSE 
complexity of its shape, and consists of two parts: the osseous labyrinth, a series 
of cavities channelled out of the substance of the petrous bone, and the membranous 
labyrinth, the latter being contained within the former. 
The Osseous Labyrinth (Labyrinthus Osseus) (Fig. 767). 
The osseous labyrinth consists of three parts: the vestibule, semicircular canals, 
and cochlea. These are cavities hollowed out of the substance of the bone, and 
lined by periosteum. A clear fluid is contained in the space between the osseous 
labyrinth and the membranous labyrinth. The space is called the perilymph 
space, and the fluid is called perilymph or liquor Cotunnii. 
The Vestibule (vestibulum) (Figs. 763 and 767).-The vestibule is the common 
central cavity of communication between the parts of the internal ear. It is situated 
on the inner side of the tympanum, behind the cochlea, and in front of the semi- 
circular canals. It is somewhat ovoidal in shape from before backward, flattened 
from within outward, and measures about one-fifth of an inch from before back- 
Opening of aqueductus vestibuli. 
Bristle passed through foramen rotundum. 
Opening of aqueductus cochleie. 
Fig. 767.-The osseous labyrinth laid open (enlarged). 
ward, as well as from above downward, and about one-eighth of an inch from with- 
out inward. On its outer or tympanic wall is the fenestra ovalis (fenestra vestibuli), 
closed, in the recent state, by the base of the stapes, and its annular ligament. 
On its inner wall, at the forepart, is a small circular depression, fovea hemi- 
sphaerica or spherical recess (recessus sphaericus), in which the saccule is placed. 
This recess is perforated, at its anterior and inferior part, by about a dozen minute 
holes (macula cribrosa media), for the passage of filaments of the auditory nerve 
to the saccule. Above and behind this depression is an oblique ridge, the crista 
vestibuli. The anterior extremity of the crista vestibuli is the shape of a triangle, 
and is called the pyramid (pyramis vestibuli). This ridge bifurcates posteriorly to 
enclose a small depression, the recessus cochlearis of Reichert, which is perforated 
by eight small holes for the passage of filaments of the auditory nerve which 
supply the posterior end of the ductus cochlearis. An oval depression is placed 
in the roof and inner wall of the vestibule above and behind the crista vestibuli. 
It is called the fovea hemielliptica, elliptical recess or spherical recess (recessus 
ellipticus), and receives the utricle. The pyramid and the adjacent elliptical 
recess are perforated by numerous minute foramina (macula cribrosa superior), THE OSSEOUS LABYRINTH 
1165 
The openings in the pyramid transmit filaments from the vestibular nerve to the 
utricle; the openings in the elliptical recess transmit filaments from the vestibular 
nerve to the ampullae of the superior and external semicircular canals. Below and 
behind the elliptical recess is a groove which deepens into a canal and is called 
the aquaeductus vestibuli. This canal passes to the posterior surface of the petrous 
portion of the temporal bone and opens as a mere crack between the internal 
auditory meatus and the groove for the lateral sinus. It transmits a small vein, 
and contains a tubular prolongation of the lining membrane of the vestibule, the 
ductus endolymphaticus, which ends in a cul-de-sac between the layers of the dura 
mater within the cranial cavity. Behind, the semicircular canals open into the 
vestibule by five orifices. In front is an elliptical opening, which communicates 
with the scala vestibuli of the cochlea by an orifice, apertura scalae vestibuli cochleae. 
This opening is bounded below by a thin plate of bone (lamina spiralis ossea), 
which takes origin from the vestibular floor external to the spherical recess and 
in the cochlea forms the bony portion of the partition between the scala tympani 
and the scala vestibuli. In the anterior portion of the vestibular floor is a fissure 
(fissura vestibuli), which passes into the bony part of the canal of the cochlea. 
The external boundary of this fissure is a small, thin plate of bone (lamina spiralis 
secundaria). 
The Semicircular Canals (canales semicirculares ossei) (Fig. 767).-The semi- 
circular canals are three bony canals situated above and behind the vestibule. They 
are of unequal length, compressed from side to side, and each describes the greater 
part of a circle. They measure about one-twentieth of an inch in diameter, and 
each presents a dilatation at one end, called the ampulla ossea, which measures 
more than twice the diameter of the tube. These canals open into the vestibule 
by five orifices, one of the apertures being common to two of the canals. 
The Superior Semicircular Canal (canalis semicircular is superior).-The superior 
semicircular canal is vertical in direction, and is placed transversely to the long 
axis of the petrous portion of the temporal bone, on the anterior surface of which 
its arch forms a round projection. It describes about two-thirds of a circle. Its 
outer extremity, which is ampullated, communicates by a distinct orifice with the 
upper part of the vestibule; the opposite end of the canal, which is not dilated, 
joins with the corresponding part of the posterior canal to form the crus commune, 
which opens into the upper and inner part of the vestibule. 
The Posterior Semicircular Canal (canalis semicircularis posterior).-The posterior 
semicircular canal, also vertical in direction, is directed backward, nearly parallel 
to the posterior surface of the petrous bone; it is the longest of the three; its ampul- 
lated end commences at the lower and back part of the vestibule, its opposite end 
joining to form the common canal already mentioned. In the wall of the ampulla 
of the posterior canal are a number of small openings (macula cribrosa inferior) 
for the entrance of nerves to the ampulla. 
The External or Horizontal Canal (canalis semicircularis lateralis).-The external 
or horizontal canal is the shortest of the three, its arch being directed outward and 
backward; thus each semicircular canal stands at right angles to the other two. 
Its ampullated end corresponds to the upper and outer angle of the vestibule, just 
above the fenestra ovalis, where it opens close to the ampullary end of the superior 
canal; its opposite end opens by a distinct orifice at the upper and back part of the 
vestibule. 
The Cochlea (Figs.767,76S,769, and 770).-The cochlea bears some resemblance 
to acommon snail-shell; it forms the anterior partof the labyrinth, is conical in form, 
and placed almost horizontally in front of the vestibule; its apex is directed forward 
and outward, with a slight inclination downward, toward the upper and front part 
of the inner wall of the tympanum; its base corresponds with the anterior depression 
at the bottom of the internal auditory meatus, and is perforated by numerous THE ORGANS OF SPECIAL SENSE 
1166 
apertures for the passage of the cochlear divisions of the auditory nerve. It meas- 
ures nearly a quarter of an inch (5 mm.) from base to apex, and its breadth across 
Fig. 768.-Osseous cochlea in vertical section. The broken, white lines indicate the position of the basilar 
membrane of the canal of the cochlea. Semidiagrainmatic. (Testut.) 
the base is somewhat greater (about 9 mm.). It consists of a conical-shaped 
central axis, the modiolus or columella; of a canal, the bony canal of the cochlea, the 
inner wall of which is formed by the central axis, wound spirally around it for two 
CANALIS 
SPIRALIS 
MODIOLI 
CANALIS LON- 
GITUDINALIS 
MODIOLI 
COMPACT BONY 
SUBSTANCE OF 
C APSULE OF 
LABYRINTH 
BASIS 
MODIOLI 
SULCUS FOR LARGE SUPER- 
FICIAL PETROSAL NERVE 
TRACTUS 
SPI RALISx 
FORMINOSUS 
LAMINA MODIOLI 
SULCUS FOR SMALL SUPER- 
'FICIAL PETROSAL NERVE 
-TEGMEN 
TYMPANI 
SEMICANAL 
.FOR TENSOR 
TYMPANI 
MUSCLE 
GLASSERIAN 
FISSURE 
AREA 
COCHLEXE 
SEMICANAL OF 
EUSTACHIAN 
TUBE 
CANALIS 
SPIRALIS' 
MODIOLI 
LAMINA 
SPIRALIS 
OSSEA 
Fig. 769.-Vertical section through the right cochlea, medial portion, viewed from the lateral side. (Spalteholz.) 
LAMINA SPIRALIS 
SECUN DARIA 
turns and three-quarters, from the base to the apex, and of a delicate lamina, the 
lamina spiralis ossea, which projects from the modiolus, and, following the windings THE OSSEOUS LABYRINTH 
1167 
of the canal, partially subdivides into two. In the recent state certain mem- 
branous layers are attached to the free border of this lamina, which project into 
the canal and completely separate it into two passages, which, however, com- 
municate with each other at the apex of the modiolus by a small opening, named 
the helicotrema. 
The Modiolus (Figs. 769and 770).-The modiolus or columella is the central axis 
or pillar of the cochlea. It is conical in form, and extends from the base to the apex 
of the cochlea. Its base (basis modioli) is broad, and appears at the bottom of the 
internal auditory meatus, where it corresponds with the area cochleae. It is per- 
forated by numerous orifices, which transmit filaments of the cochlear division 
of the auditory nerve, the nerves for the first turn and a half being transmitted 
through the foramina of the tractus spiralis foraminosus; the fibres for the apical 
turn passing up through the foramen centrale. The foramina of the tractus 
spiralis foraminosus pass up through the modiolus and successively bend out- 
ward to reach the attached margin of the lamina spiralis ossea. Here they become 
enlarged, and by their apposition form a spiral canal (canalis spiralis modioli), 
which follows the course of the attached margin of the lamina spiralis ossea and 
lodges the ganglion of Corti (ganglion spirale cochleae). The foramen centrale is 
continued as a canal up the middle of the modiolus to its apex, and from this canal 
numerous minute foramina pass outward to the unattached edge of the lamina 
spiralis. In the foramina are vessels and nerves. The axis diminishes rapidly 
in size in the second and succeeding coil. 
Fig. 770.-The cochlea laid open (enlarged). 
The Bony Canal or the Spiral Canal of the Cochlea (canalis spiralis cochleae) (Fig. 
770).-The bony canal of the cochlea takes two turns and three-quarters round the 
modiolus. The first turn of the canal is called the basal coil, the second is called the 
central coil, the third turn is called the apical coil. The promontory on the inner wall 
of the tympanic cavity is caused by the basal coil. The bony canal of the cochlea is 
a little over an inch in length (about 30 mm.), and diminishes gradually in size from 
the base to the summit, where it terminates in a cul-de-sac, the cupola (cupula), which 
forms the apex of the cochlea. The commencement of this canal is about the 
tenth of an inch in diameter; it diverges from the modiolus toward the tympanum 
and vestibule, and presents three openings. One, the fenestra rotunda, commu- 
nicates with the tympanum; in the recent state this aperture is closed by a mem- 
brane, the membrana tympani secundaria. Another aperture, of an elliptical form, 
enters the vestibule. The third is the aperture of the aquaeductus cochleae, leading 
to a minute funnel-shaped canal, which opens on the basilar surface of the petrous 
bone internal to the jugular fossa, and transmits a small vein, and also forms 
a communication between the subarachnoidean space of the skull and the peri- 
lymph contained in the scala tympani. 
The Lamina Spiralis Ossea.-The lamina spiralis ossea is a bony shelf or ledge 
which projects outward from the modiolus into the interior of the spiral canal, 
and, like the canal, takes two and three-quarter turns around the modiolus. It 
reaches about half-way toward the outer wall of the spiral tube, and partially 
divides its cavity into two passages or scalae, of which the upper is named the 
scala vestibuli, while the lower is termed the scala tympani. Near the summit of 
the cochlea the lamina terminates in a hook-shaped process, the hamulus (hamulus 
laminae spiralis), which assists in forming the boundary of a small opening, the 
helicotrema, by which the two scalae communicate with each other. From the 
canalis spiralis modioli numerous foramina pass outward through the osseous 
spiral lamina as far as its outer or free edge. In the lower part of the first turn 
a second bony lamina (lamina spiralis secundaria) projects inward from the 
outer wall of the bony tube; it does not, however, reach the primary osseous spiral 
lamina, so that if viewed from the vestibule a narrow fissure, the fissura vestibuli, 
is seen between them. 
The membrana basilaris (Fig. 768) is stretched from the unattached edge of 
the lamina spiralis ossea to the outer wall of the cochlea. The lamina spiralis 
UTRICLE 
NERVE OF AMPULLA 
OF SUPERIOR CANAL 
AMPULLA OF SUPERIOR 
MEMBRANOUS CANAL 
DUCT OF 
SUPERIOR 
SEMICIRCULAR 
CANAL 
SUPERIOR 
TERMINAL 
BRANCH OF. 
VESTI BULAR 
NERVE 
AMPULLA OF 
EXTERNAL 
MEMBRANOUS 
CANAL 
DUCTUS 
COCHLEARIS 
COCHLEAR 
NERVE 
DUCT OF 
EXTERNAL 
SEMICIRCULAR 
CANAL 
ACOUSTIC 
NERVE 
CRUS 
COM MUNE 
VESTIBULAR 
NERVE 
DUCT OF 
POSTERIOR 
SEMICIRCULAR 
CANAL 
VESTIBULAR 
GANGLION 
DUCTUS ENDO. 
LYM PHATICUS 
NERVE OF 
SACCULE 
NERVE OF AMPULLA 
OF POSTERIOR CANAL 
SACCU LE 
AMPULLA OF POSTERIOR 
MEMBRANOUS CANAL 
makes an incomplete septum between the scala tympani and scala vestibuli; the 
membrana basilaris completes the septum. Even with the perfected septum the 
two scalae communicate at the apex of the cochlea by means of the helicotrema. 
The Fundus of the Internal Auditory Meatus (fundus meatus acustici interni).- 
This structure is the inner wall of the vestibule and the base of the modiolus. A 
transverse ridge (crista transversa) maps it off into two parts, the fossula superior 
and the fossula inferior. The facial area (arean. facialis) is in the anterior portion 
of the fossula superior. 'The opening seen here is the beginning of the aqueduct 
of Fallopius (canalis facialis) for the transmission of the facial nerve. The superior 
area of the vestibule (area vestibularis superior) is the posterior portion of the fossula 
superior. Here the nerves perforate which supply the utricle and the ampullae of 
the superior and external semicircular canals (Cunningham). The area cochleae 
is the anterior portion of the fossula inferior. In it is the canalis centralis for the 
nerve-fibres to the apical turn of the cochlea; and the tract us spiralis for aminosa 
for the transmission of nerves to the first turn and a half of the cochlea. The 
Fig. 771.-The right membranous labyrinth of an adult, isolated, medial and posterior view. (Spalteholz.) THE MEMBRANOUS LABYRINTH 
1169 
inferior area of the vestibule (area vestibularis inferior) is back of the area cochleae 
and a ridge separates the two. It transmits nerves to the saccule. At the posterior 
part of the fossula inferior is a solitary foramen, the foramen singulare, which 
transmits nerves to the ampulla of the posterior semicircular canal. 
The Membranous Labyrinth (Labyrinthus Membranaceus) (Figs. 771, 772). 
The membranous labyrinth is contained within the bony cavities just described, 
having the same general form as the cavities in which it is contained, though 
considerably smaller, being separated from the bony walls by a quantity of fluid, 
the perilymph or liquor Cotunnii {perilympha). It does not, however, float loosely 
in this fluid, but in places is fixed to the walls of the cavity. The membranous 
sac contains fluid, the endolymph {endolympha), and on the sac the ramifications 
of the auditory nerve are distributed. 
Within the osseous vestibule the membranous labyrinth does not quite preserve 
the form of the bony cavity, but presents two membranous sacs, the utricle and 
the saccule. 
Ampullae 
Saccule 
Ampulla 
Canalis 
Reuniens 
Ductus 
Endolymphaticus 
Fig. 772.-The membranous labyrinth (enlarged). 
The Utricle (utriculus).-The utricle is the larger of the two, of an oblong 
form, compressed laterally, and occupies the upper and back part of the vestibule, 
lying in contact with the fovea semi-elliptica and the part below it. The highest 
portion of the utricle is called the recess (recessus utriculi); it is placed in the 
elliptical recess, and opening into it are the ampulla of the superior and external 
semicircular canals. The central portion of the recess of the utricle receives upon 
the side the external semicircular canal. This opening has not an ampulla. The 
superior sinus is a prolongation upward and backward from the central portion of 
the utricle and in the superior sinus the crus commune and the superior and 
posterior semicircular canals open. The lower and inner portion of the utricle 
is the inferior sinus, and into it the ampulla of the posterior semicircular canal 
opens. The floor and anterior wall of the recess of the utricle are much thicker 
than elsewhere, and form the macula acustica utriculi, which receives the utricular 
filaments of the auditory nerve and has attached to its internal surface a layer of 
calcareous particles which are called otoliths. The cavity of the utricle communi- 
cates behind with the membranous semicircular canals by five orifices. From 
its anterior wall is given off a small canal (ductus utriculosaccularis), which joins 
with a canal from the saccule, the ductus endolymphaticus. The utricle is joined 
to the bony wall by numerous fibrous bands. 1170 
THE ORGANS OF SPECIAL SENSE 
The Saccule (sacculus).-The saccule is the smaller of the two vesicular sacs; 
it is globular in form, lies in the elliptical recess near the opening of the scala 
vestibuli of the cochlea. Its anterior part exhibits an oval thickening, the macula 
acustica sacculi, to which are distributed the saccular filaments of the auditory 
nerve. Its cavity does not directly communicate with that of the utricle. From 
the posterior wall is given off a canal, the ductus endolymphaticus. This duct 
passes along the aquaeductus vestibuli and ends in a blind pouch on the posterior 
surface of the petrous portion of the temporal bone, where it is in contact with 
the dura mater. The upper extremity of the saccule looks upward and back- 
ward and forms the sinus utricularis sacculi. This lies in contact with but is not 
a part of the wall of the utricle. The vestibule contains the closed end of the 
ductus cochlearis. This is known as the caecum vestibulare. The ductus coch- 
learis lies below the saccule in what Reichert described as the recessus cochlearis, 
and it enters the spiral canal. From the lower part of the saccule a short tube, 
the canalis reuniens of Hensen (ductus reuniens \Hensem\), passes downward 
and outward to open into the ductus cochlearis. The saccule is held in posi- 
tion by numerous fibrous bands which pass between the saccule and the bony 
wall. 
The Membranous Semicircular Canals (ductus semicirculares).-The mem- 
branous semicircular canals are about one-third the diameter of the osseous canals, 
but in number, shape, and general form they are precisely similar, and present 
at one end within the osseous ampulla a membranous ampulla. These ampullae 
are called ampullae membranaceae. The canals open by five orifices into the utricle, 
one opening being common to two canals. In the ampullae the wall is thickened, 
and projects into the cavity as a fiddle-shaped, transversely placed elevation, the 
septum transversum, in which the nerves end. 
The membranous canals are attached here and there to the bone by numerous 
fibrous bands, the so-called ligaments (ligamenta labyrinthi canaliculorum). 
Structure.-The walls of the utricle, saccule, and membranous semicircular 
canals consist of three layers. The outer layer is a loose and flocculent struc- 
ture, apparently composed of ordinary fibrous tissue, containing blood-vessels 
and pigment-cells analogous to those in the pigment coat of the retina. The 
middle layer, thicker and more transparent, bears some resemblance to the 
hyaloid membrane, but it presents on its internal surface, especially in the semi- 
circular canals, numerous papilliform projections, and, on the addition of acetic 
acid, presents an appearance of longitudinal fibrillation and elongated nuclei. 
The inner layer is formed of polygonal nucleated epithelial cells. The raphe of 
each semicircular canal is a line upon the concave side of the canal. Along the 
raphe the height of the epithelial cells is distinctly increased. In the ampullae 
adjacent to the cristae acusticae the cells are cylindrical and constitute the 
plana semilunata. In the maculae of the utricle and saccule, and in the trans- 
verse septa of the ampullae of the canals, the middle coat is thickened and the 
epithelium is columnar, is increased in height, and passes into the neuro-epithe- 
lium. The neuro-epithelium consists of supporting cells and hair-cells. 
1. The supporting cells are long, wider at the ends than in the centre, contain an 
oval nucleus, and the lower end of the cell is fissured. 
2. The hair-cells are columnar, with bulged lower ends and free upper ends. 
The bulged lower ends, each of which contains a spherical nucleus, do not reach 
higher than the middle of the epithelial layer. Each free upper end is surmounted 
by a long, tapering filament. These filaments constitute auditory hair, and they 
project into the cavity. The filaments of the auditory nerve enter these parts, 
and, having pierced the outer and thickened middle layer, they lose their medul- 
lary sheath, and their axis-cylinders divide into three or four branches at the 
larger and deeper ends of the hair-cells. These branches form a horizontal plexus THE MEMBRANOUS LABYRINTH 
1171 
(stratum plexijorme). "These surround the hair-cells like the calyx of a flower, 
and give off ascending branches, which, however, do not reach the surface. In 
this way one branch usually comes in contact with many hair-cells."1 
Membrane of Corti. 
Sulcus spiralis. 
Organ of Corti. 
Membrana basilaris. 
Fig. 773.-Floor of scala media, showing the organ of Corti, etc. 
Numerous small prismatic bodies termed statoliths, otokonien crystals or otoliths, 
and consisting of a mass of minute crystalline grains of carbonate of lime, held 
CANAL OF 
COCHLEA 
LAMINA SPIRALIS 
.COCHLEAR NERVE 
AND GANGLION 
Fig. 774.-Cochlea in transverse section. Observe especially the canal of the cochlea, which is a part of 
the membranous labyrinth. (Testut.) 
together in a mesh of delicate fibrous tissue, are contained in the walls of the 
utricle and saccule opposite the distribution of the nerves. The membrane is 
' Histology and Microscopic Anatomy. By Dr. Ladislaus Szymonowicz. Translated and edited by John 
Bruce MacCallum, M.D. 1172 
THE ORGANS OF SPECIAL SENSE 
calk'd the otolith membrane. A calcareous material is also, according to Bowman, 
sparingly scattered in the cells lining the ampullae of the semicircular canals. The 
conical thickening in the ampulla corresponds to the otolith membrane and is 
called the cupola. 
The Membranous Cochlea Ductus Cochlearis or Scala Media consists of a spirally 
arranged tube enclosed in the bony canal of the cochlea and lying along its outer 
wall. It begins as a blind end in the recessus cochlearis of the vestibule. This 
beginning is the caecum vestibulare. It ascends inside the bony cochlea and termi- 
nates at the apex of the cochlea by a blind end, the lagena (caecum cupulare). The 
manner in which it is formed will now be described. 
The osseous spiral lamina, as above stated, extends only part of the distance be- 
tween the modiolus and the outer bony wall of the cochlea. A membrane, the basilar 
membrane (membrana basilaris) (Fig. 773), stretches from its free edge to the outer 
wall of the cochlea,and completes the roof of the scala tympani. A second and more 
delicate membrane, the membrane of Reissner (membrana vestibularis [Reissneri]) 
(Fig.773),extends from the thickened periosteum covering the lamina spiralis ossea 
to the outer wall of the cochlea, to which it is attached at some little distance above 
the membrana basilaris. A canal is thus shut off between the scala tympani below 
and the scala vestibuli above; this is the membranous canal of the cochlea (ductus 
cochlearis or scala media) (Fig. 774). It is triangular on transverse section, its roof 
being formed by the membrane of Reissner, its outer wall by the periosteum which 
lines the bony canal, and its floor by the membrana basilaris, and the outer part 
of the lamina spiralis ossea, on the former of which is placed the organ of Corti. 
Reissner's membrane is thin and homogeneous, and is covered on its upper and 
under surfaces by a layer of epithelium. The periosteum, which forms the outer 
wall of the ductus cochlearis, is greatly 
thickened and altered in character, 
forming what is called the spiral liga- 
ment of the cochlea (lig amentum spirale 
cochleae) (Fig.773). It projects inward 
below as a triangular prominence, the 
crista basilaris, which gives attach- 
ment to the outer edge of the mem- 
brana basilaris,and immediately above 
which is a concavity, the sulcus spiralis 
externus (Fig. 773). The upper por- 
tion of the ligamentum spirale con- 
tains numerous capillary loops and 
small blood-vessels, and forms what 
is termed the stria vascularis. The stria is limited below by a prominence (promi- 
nentia spiralis), in which a blood-vessel (vas prominens) is distinctly visible. 
The lamina spiralis ossea (Fig. 774) consists of two plates of bone extending 
outward; between these are the canals for the transmission of the filaments of the 
auditory nerve. On the upper plate of that part of the osseous spiral lamina 
which is outside Reissner's membrane the periosteum is thickened to form the 
limbus laminae spiralis, and this terminates externally in a concavity, the sulcus 
spiralis internus, which presents, on section, the form of the letter C; the upper 
part of the letter, formed by the overhanging extremity of the limbus, is named 
the labium vestibulare; the lower part, prolonged and tapering, is called the labium 
tympanicum, and is perforated by 4000 foramina (foramina nervosa) for the pass- 
age of the cochlear nerves. Externally, the labium tympanicum is continuous 
with the membrana basilaris. The upper surface of the labium vestibulare is 
intersected at right angles by a number of furrows, between which are numerous 
elevations; these present the appearance of teeth along the free margin of the 
NERVE-FIBRES PASSING OUT 
BETWEEN THE TWO LAYERS OF 
LAMI.NA SPIRALIS OSSEA 
GANGLION 
SPIRALE 
SPIRAL 
FIBRES 
Fig. 775.-Part of the cochlear nerve, highly magnified. 
(Henle.) THE MEMBRANOUS LABYRINTH 
1173 
labium, and have been named by Huschke the auditory teeth. There are 7000 
auditory teeth. The basilar membrane may be divided into two areas, inner and 
outer. The inner is thin, and is named the zona arcuata or zona tecta (Fig. 773); it 
supports the organ of Corti. The outer is thicker and striated, and is termed 
the zona pectinata. The under surface of the membrane is covered by a layer of 
Membrana tectoria. 
Outer hair cells. 
Limbus. 
Inner hair cells.- 
Vas spirale. 
Cells of Deiters. 
Nerve fibres. 
Inner rod. 
Basilar membrane. 
Outer rod. 
Fig. 776.-Section through the organ of Corti. Magnified. (G. Retzius.) 
vascular connective tissue. One of these vessels is somewhat larger than the rest, 
and is named the vas spirale (Fig. 776); it lies below Corti's tunnel. 
Organ of Corti1 (organon spirale [Corfu]) (Figs. 773, 774, 776, and 777).-The 
inner part of the membrana basilaris-that is, the part directed toward the canal 
of the ductus cochlearis-is covered with epithelium, which is largely neuro-epithe- 
INTERNAL AUDI- 
TORY CELLS 
INTERNAL 
ROD 
Fig. 777.-Organ of Corti. Diagrammatic view of a small portion. (Testut.) 
Hum. It forms the organ of Corti. In this lie the terminations of the cochlear 
nerve. It appears at first sight as a papilla, winding spirally throughout the 
whole length of the ductus cochlearis, from which circumstance it has been desig- 
nated the papilla spiralis. More accurately viewed, it is seen to be composed 
of a remarkable arrangement of cells, which may be likened to the keyboard of a 
' Corti's original paper is in the Zeitschrift f. Wissen. Zool., iii., 109. 1174 
THE ORGANS OF SPECIAL SENSE 
pianoforte. The organ of Corti consists of an inner part and an outer part. Each 
part contains auditory cells and supporting cells. Of these cells, the two central 
ones are rod-like bodies and are called the inner and outer rods of Corti. They are 
placed on the basilar membrane, at some little distance from each other, but are 
inclined toward each other, so as to meet at their opposite extremities, and form 
a series of arches roofing over a minute tunnel, the canal or tunnel of Corti, 
between them and the basilar membrane, which ascends spirally through the 
whole length of the cochlea. 
The inner rods (Fig. 776), some 6000 in number, are more numerous than the 
outer ones, and rest on the basilar membrane, close to the labium tympanicum; 
they project obliquely upward and outward, and terminate above in expanded 
extremities which resemble in shape the upper end of the ulna, with its sigmoid 
cavity, coronoid and olecranon processes. On the outer side of the rod, in the 
angle formed between it and the basilar membrane, is a nucleated mass of proto- 
plasm; while on the inner side is a row of epithelial cells, inner hair-cells (Fig. 
776), surmounted by a brush of fine, stiff, hair-like processes. On the inner side 
of these cells are two or three rows of columnar supporting cells, which are 
continuous with the cubical cells lining the sulcus spiralis internus. 
Fig. 778.-Longitudinal section of the cochlea, showing the relations of the scalae, the ganglion spirale, etc. 
S. V., Scala vestibuli. S. T., Scala tympani. S. M., Scala media. L. S., Ligamentum spirale. G. S., Ganglion 
spirale. 
The outer rods (Fig. 776), numbering about 4000, also rest by a broad foot on 
the basilar membrane; they incline upward and inward, and their upper extremity 
resembles the head and bill of a swan; the back of the head fitting into the con- 
cavity-the analogue of the sigmoid cavity-of one or more of the internal rods, 
and the bill projecting outward as a phalangeal process of the membrana reticu- 
laris, presently to be described. 
In the head of these outer rods is an oval portion, where the fibres of which 
the rod appears to be composed are deficient, and which stains more deeply with 
carmine than the rest of the rod. At the base of the rod, on its internal side- 
that is to say, in the angle formed by the rod with the basilar membrane-is a 
similar protoplasmic mass to that found on the outer side of the base of the inner 
rod; these masses of protoplasm are probably the undifferentiated portions of the 
cells from which the rods are developed. External to the outer rod are three or 
four successive rows of epithelial cells, more elongated than those found on the THE MEMBRANOUS LABYRINTH 
1175 
internal side of the inner rod, but, like them, furnished with minute hairs or cilia. 
These are termed the outer hair-cells, in contradistinction to the inner hair-cells 
above referred to. There are about 12,000 outer hair-cells, and about 3500 inner 
hair-cells. 
The hair-cells are somewhat oval in shape; their free extremities are on a 
level with the heads of Corti's rods, and from each some twenty fine hairlets 
project and are arranged in the form of a crescent, the concavity of which opens 
inward. The deep ends of the cells are rounded and contain large nuclei; they 
reach only as far as the middle of Corti's rods, and are in contact with the rami- 
fications of the nervous filaments. Between the rows of the outer hair-cells 
are rows of supporting cells, called the cells of Deiters; their expanded bases are 
planted on the basilar membrane, while their opposite ends present a clubbed 
extremity or phalangeal process. Immediately to the outer side of Deiters's cells 
are some five or six rows of columnar cells, the supporting cells of Hensen. Their 
bases are narrow, while their upper parts are expanded and form a rounded 
elevation on the floor of the ductus cochlearis. The columnar cells lying outside 
Hensen's cells are termed the cells of Claudius. A space is seen between the 
outer rods of Corti and the adjacent hair-cells; this is called the space of Nuel. 
The lamina reticularis or membrane of Kolliker is a delicate framework per- 
forated by rounded holes. It extends from the inner rods of Corti to the external 
row of the outer hair-cells, and is formed by several rows of "minute fiddle- 
shaped cuticular structures" called phalanges, between which are circular 
apertures containing the free ends of the hair-cells. The innermost row of phal- 
anges consists of the phalangeal processes of the outer rods of Corti; the outer 
rows are formed by the modified free ends of Deiters's cells. 
Covering over these structures, but not touching them, is the membrana tectoria 
or membrane of Corti (Figs. 773 and 776), which is attached to the vestibular sur- 
face of the lamina spiralis close to the attachment of the membrane of Reissner. 
It is thin near its inner margin, and overlies the auditory teeth of Huschke. Its 
outer half is thick, and along its lower edge, opposite the inner hair-cells, is a 
clear band, named Hensen's stripe. Externally, the membrane becomes much 
thinner, and is attached to the outer row of Deiters's cells (Retzius). 
The fibres from the cochlear nerve enter the organ of Corti as axis-cylinders, 
which pass directly to the deepest portions of the inner and outer hair-cells by 
way of the canal of Corti or by the space of Nuel. The terminations arborize 
about the lower portions of the hair-cells and end on the surfaces of the hair-cells. 
The inner surface of the osseous labyrinth is lined by an exceedingly thin fibro- 
serous membrane, analogous to a periosteum, from its close adhesion to the 
inner surfaces of these cavities, and performing the office of a serous membrane by 
its free surface. It lines the vestibule, and from this cavity is continued into the 
semicircular canals and the scala vestibuli of the cochlea, and through the helico- 
trema into the scala tympani. A delicate tubular process is prolonged along the 
aqueduct of the vestibule to the inner surface of the dura mater. This membrane 
is continued across the fenestra ovalis and fenestra rotunda, and consequently has 
no communication with the lining membrane of the tympanum. Its attached 
surface is rough and fibrous, and closely adherent to the bone; its free surface is 
smooth and pale, covered with a layer of epithelium, and secretes a thin, limpid 
fluid, the aqua labyrinthi, liquor Cotunnii or perilymph (Blainville). 
The scala media is closed above and below. The upper blind extremity is 
termed the lagena, and is attached to the cupola at the upper part of the helico- 
trema; the lower end is lodged in the recessus cochlearis of the vestibule. Near 
this blind extremity, the scala media receives the canalis reunions of Hensen (Fig. 
772), a very delicate canal, by which the ductus cochlearis is brought into con- 
tinuity with the saccule. THE ORGANS OF SPECIAL SENSE 
1176 
The Arteries of the Labyrinth.-The arteries of the labyrinth are the internal 
auditory, from the basilar, and the stylo-mastoid, from the posterior auricular. 
The internal auditory divides at the bottom of the internal auditory meatus 
into two branches, cochlear and vestibular. 
The cochlear artery divides into numerous minute branches, which enter 
foramina in the tractus spiralis foraminosa and course in the lamina spiralis ossea 
to reach the membranous structures. The largest of the cochlear branches is in 
the canalis centralis. 
The vestibular branches accompany the nerves, and supply the membranous 
structures in the vestibule and semicircular canals. Two arteries go to each 
canal. The two vessels enter opposite extremities of the canal, and anastomose 
at the summit of the canal. The vestibular vessels form a minute capillary net- 
work in the substance of each membranous labyrinth. 
The Veins of the Labyrinth.-The veins of the vestibule and semicircular canals, 
the auditory veins, accompany the arteries, and receive those of the cochlea at the 
base of the modiolus, to form the internal auditory vein {vv. auditivae internae), 
which opens into the posterior part of the inferior petrosal sinus or into the lateral 
sinus. 
The Nerves of the Labyrinth.-The auditory nerve {n. acusticus), the special nerve 
of the sense of hearing, divides, at the bottom of the internal auditory meatus, 
into two branches, the cochlear and vestibular. 
The Vestibular Nerve (n. vestibularis), the posterior of the two, presents, as it lies 
in the internal auditory meatus, a ganglion, the vestibular ganglion or the ganglion 
of Scarpa {ganglion vestibulare); the nerve divides into three branches which pass 
through minute openings at the upper and back part of the bottom of the meatus 
{area vestibular posterior), and, entering the vestibule, are distributed to the utricle 
and to the ampulla of the external and superior semicircular canals. 
The nervous filaments enter the ampullary enlargements opposite the septum 
transversum, and arborize around the hair-cells. In the utricle and saccule the 
nerve-fibres pierce the membrana propria of the maculae, and end in arborizations 
around the hair-cells. 
The Cochlear Nerve {n. cochlearis) gives off the branch to the saccule, the fila- 
ments of which are transmitted from the internal auditory meatus through the 
foramina of the area vestibularis inferior, which lies at the lower and back part 
of the floor of the meatus. It also gives off the branch for the ampulla of the 
posterior semicircular canal, which leaves the meatus through the foramen singulare. 
The rest of the cochlear nerve divides into numerous filaments at the base 
of the modiolus; those for the basal and middle coils pass through the foramina 
in the tractus foraminosus, those for the apical coil through the canalis centralis, 
and the nerves bend outward to pass between the lamellae of the osseous spiral 
lamina. Occupying the spiral canal of the modiolus is the spiral ganglion or gan- 
glion of Corti {ganglion spirale), consisting of bipolar nerve-cells, which really con- 
stitute the true cells of origin of this nerve, one pole being prolonged centrally to 
the brain and the other peripherally to the hair-cells of Corti's organ. Reaching the 
outer edge of the osseous spiral lamina, the nerve fibres pass through the foramina 
in the labium tympanicum, where they lose their axis-cylinders. They enter the 
organ of Corti and pass directly to the deep portions of the inner and outer hair-cells 
by way of the canal of Corti and the space of Nuel. The terminations arborize 
about the lower portions of the hair-cells and end in the surfaces of the cells. 
Surgical Anatomy.-Malformations, such as imperfect development of the external parts, 
absence of the meatus, or supernumerary auricles, are occasionally met with. Or the pinna may 
present a congenital fistula, which is due to defective closure of the first visceral cleft, or rather 
of that portion of it which is not concerned in the formation of the Eustachian tube, tympanum, 
and meatus. In some cases the cephalo-auricular angle is almost absent; in others it is nearly 7 HE MEMBRANOUS LABYRINTH 
1177 
a right angle. Projecting ears and long ears are said by some observers to be more common 
among degenerates, criminals, and the insane than among the normal, the non-criminal, and 
the sane. The skin of the auricle is thin and richly supplied with blood, but in spite of this it 
is frequently the seat of frost-bite, due to the fact that it is much exposed to cold, and lacks the 
usual underlying subcutaneous fat found in most other parts of the body. A collection of blood 
is sometimes found between the cartilage and perichondrium (haematoma aurisj, usually the 
result of traumatism, but not necessarily due to this cause. It is said to occur most frequently 
in the ears of the insane. Keloid sometimes grows in the auricle around the puncture made for 
ear-rings, and epithelioma occasionally affects this part. Deposits of urate of soda are often met 
with in the pinna in gouty subjects. 
The external auditory meatus can be most satisfactorily examined by light reflected down a 
funnel-shaped speculum; by gently moving the latter in different directions the whole of the 
canal and membrana tympani can be brought into view. The points to be noted are: the pres- 
ence of wax or foreign bodies, the size of the canal, and the condition of the membrana tympani. 
The accumulation of wax is often the cause of deafness, and may give rise to very serious conse- 
quences, causing ulceration of the membrane and even absorption of the bony wall of the canal. 
Foreign bodies are not infrequently introduced into the ear by children, and, when situated in 
the first portion of the canal, may be removed with tolerable facility by means of a minute hook 
or loop of fine wire, the parts being illuminated with reflected light; but when they have slipped 
beyond the narrow middle part of the meatus, their removal is in nowise easy, and attempts to effect 
it, in inexperienced hands, may be followed by destruction of the membrana tympani and possibly 
injury of the contents of the tympanum. The calibre of the external auditory canal may be nar- 
rowed by inflammation of its lining membrane, running on to suppuration; by periostitis; by polypi, 
sebaceous tumors, and. exostoses. The membrana tympani, when seen in a healthy ear, "reflects 
light strongly, and, owing to its peculiar curvature, presents a bright spot of triangular shape at its 
lower and anterior portion." From the apex of this, proceeding upward and slightly forward, is 
a white streak formed by the handle of the malleus, while near the upper part of the membrane 
may be seen a slight projection, caused by the short process of the malleus. In disease alterations 
in color, lustre, curvature or inclination, and perforation must be noted. Such perforations may 
be caused by a blow, a loud report, a wound, or as the result of suppuration in the middle ear. 
The upper wall of the meatus is separated from the cranial cavity by a thin plate of bone; 
the anterior wall is separated from the temporo-mandibular joint and parotid gland by the bone 
forming the glenoid fossa; and the posterior wall is in relation with the mastoid cells; hence 
inflammation of the external auditory meatus may readily extend to the membranes of the brain, 
to the temporo-mandibular joint, or to the mastoid cells; and, in addition to this, blows on the 
chin may cause fracture of the wall of the meatus. 
The nerves supplying the meatus are the auricular branch of the pneumogastric, the auriculo- 
temporal, and the auricularis magnus. The connections of these nerves explain the fact of the 
occurrence, in cases of any irritation of the meatus, of constant coughing and sneezing from 
implication of the pneumogastric, or of yawning from implication of the auriculo-temporal. No 
doubt also the association of earache with toothache in cancer of the tongue is due to implication 
of the same nerve, a branch of the fifth, which supplies also the teeth and the tongue. The 
vessels of the meatus and membrana tympani are derived from the posterior auricular, temporal, 
and internal maxillary arteries. The upper half of the membrana tympani is much more richly 
supplied with blood than the lower half. For this reason, and also to avoid the chorda tympani 
nerve and ossicles, incisions through the membrane should be made at the lower and posterior 
part. 
The principal point in connection with the surgical anatomy of the tympanum is its relations 
to other parts. Its roof is formed by a thin plate of bone, which, w ith the dura mater, is all that 
separates it from the temporal lobe of the brain. Its floor is immediately above the jugular 
fossa and the carotid canal, the fossa being behind and the canal in front. Its posterior wall pre- 
sents the openings of the mastoid cells. On its anterior wall is the opening of the Eustachian 
tube. Thus it follows that in disease of the middle ear we may get subdural abscess, septic 
meningitis, or abscess of the cerebrum or cerebellum from extension of the inflammation through 
the bony roof; thrombosis of the lateral sinus, with or without pyaemia, by extension through the 
floor; or mastoid abscess by extension backward. In addition to this, we may get fatal hemorrhage 
from the internal carotid in destructive changes of the middle ear ; and in throat disease we may 
get the inflammation extending up the Eustachian tube to the middle ear. The Eustachian tube 
is accessible from the nose. If the nose and mouth be closed and an attempt made to expire air, a 
sense of pressure with dulness of hearing is produced in both ears, from the air finding its way up 
the Eustachian tube and bulging out the membrana tympani. During the act of swallowing, the 
pharyngeal orifice of the tube, which is normally closed, is opened, probably by the action of 
the Dilator tubea muscle. This fact was employed by Politzer in devising an easy method of 
inflating the tube. The nozzle of an india-rubber syringe is inserted into the nostril; the patient 
takes a mouthful of water and holds it in his mouth, both nostrils are closed with the finger and 
thumb to prevent the escape of air, and the patient is then requested to swallow; as he does so the 1178 
THE ORGANS OF SPECIAL SENSE 
surgeon squeezes the bulb and the air is forced out of the syringe into his nose, and is driven into 
the Eustachian tube, which is now open. The impact of the air against the membrana tympani 
can be heard by the surgeon, if the membrane is intact, sound being conveyed by means of a 
piece of india-rubber tubing, one end of which is inserted into the meatus of the patient's ear, the 
other into that of the surgeon. The direct examination of the Eustachian tube is made by the 
Eustachian catheter. This is passed along the floor of the nostril, close to the septum, with 
the point touching the floor, to the posterior wall of the pharynx. When this is felt, the catheter 
is to be withdrawn about half an inch, and the point rotated outward through a quarter of a 
circle, and pushed again slightly backward, when it will enter the orifice of the tube, and will 
be found to be caught, and air forced into the catheter will be heard impinging on the tympanic 
membrane if the ears of the patient and surgeon are connected by an india-rubber tube. 
THE SKIN (INTEGUMENTUM COMMUNE). 
The skin covers the body surface and is continuous with the mucous membrane 
at the origin and termination of the alimentary canal and at the openings of other 
canals. The skin is a protective coat, a regulator of body-temperature, contains 
multitudes of the terminations of sensory nerves, and is the seat of the organ of 
touch (organon tactus). These nerve-terminations are connected with nerve-fibres of 
temperature, pressure, and pain. Connected with the skin are sweat-glands which 
have important excretory functions and sebaceous glands. From its superficial part 
come appendages, the hairs, and nails. The skin is elastic and varies in thickness 
from 0.5 mm. to 4 mm. It is thinnest in the eyelids and prepuce, and thickest over 
the back of the neck, back of the shoulders, palms of the hands, and soles of the 
feet. Its color depends in part on the blood within it, and in part upon pigment. 
The deepest hue is about the anus, in the genital region, in the axillae, over the 
mammary glands, and in the parts exposed to air, light, and varied temperatures. 
The color varies with age, being pinkish in extreme youth and becoming yellow 
in old age. It varies with exposure and with climate, being deepest in those who 
brave all weathers and temperatures and in those who dwell beneath a tropical sun. 
It also varies with race, and this is 
so well recognized that races are class- 
ified by the color of the skin into the 
Black, White, Yellow, and Brown races. 
The color of the skin is also affected 
in certain diseases; being extremely 
pale in anaemia, brown in Addison's 
disease, yellow in jaundice, etc. 
In most situations the skin is mova- 
ble, but in some it is attached closely 
to underlying structures, and is con- 
sequently immovable on the scalp, 
the palms of the hands, the soles of 
the feet, and the outer portion of the 
pinna of the ear. The skin is fairly 
smooth, but close examination dis- 
closes multitudes of openings,creases, 
furrows, depressions, folds, and hairs. 
Hair-follicles open upon the surface, 
and the ducts of sebaceous glands 
and of sweat-glands perforate the skin. 
About the joints are folds of skin (retinacula cutis), and temporary folds or 
wrinkles are created by the contraction of superficial muscles. The jacial wrinkles 
of advancing years are due to habitual expression and loss of skin elasticity. A 
dimple is a permanent pit or depression due to adhesion of the surface to parts 
beneath. The ridges and furrows on the palms, soles, and flexor aspects of the 
RIDGES OF 
skin' 
FURROWS 
*OF SKIN 
FLEXION FURROWS 
OPPOSITE THE 
' FLEXURE OF 
THE JOINT 
LONGITUDINAL 
FURROWS1 
RIDGES OF SKIN 
INTERRUPTED BY 
LO N GITU DI N AC 
FURROWS 
Fig. 779.-The furrows and ridges of the surface of the 
skin from the palm or surface of the middle finger. (Toldt.) THE SKIN 
1179 
digits are permanent, and over the palmar surface of the digits they are arranged 
in definite forms which endure through life and are so distinctive that they have 
been utilized by police officials in determining the identity of individuals. These 
folds are due to the papillae of the skin being arranged in rows; some of the papillae 
proliferate, and linear depressions occur in the horny layer (Philippson). 
Fig. 780.-Anterior surface. Fig. 781.-Posterior surface. 
The general course of the connective-tissue bundles of the corium, determined by the direction assumed by the 
linear clefts made in the skin when it is punctured by a round awl. (Langer.) 
Fig. 779 shows skin ridges (crist ae cutis), skin furrows (sulci cutis), furrows 
opposite joints due to acts of flexion, and called flexure furrows, and longitudinal 
furrows. 
When the skin is punctured by a round awl it tends to split in a definite 
direction, which direction varies with the region stabbed. These clefts are known THE ORGANS OF SPECIAL SENSE 
1180 
as the lines of cleavage of Langer (Figs. 780 and 781), and depend upon the 
arrangement of the connective-tissue bundles of the corium. These connective- 
tissue bundles certainly influence the formation of folds and furrows. In many 
portions of the body the cutaneous surface is divided by linear furrows into irregu- 
larly shaped areas (Fig. 782). The skin consists of two layers: a superficial layer, 
the epidermis, and a deep layer, the corium or dermis. 
The Corium, Cutis Vera, Dermis or True Skin (Figs. 783, 784, and 786) is a 
connective-tissue structure which arises from the mesoderm. It consists espe- 
cially of connective tissue and elastic fibres; it contributes elasticity to the skin, 
and is the seat of the sensitive layer. The corium is composed of two layers, 
the reticular and the papillary. 
MOUTH OF 
HAIR-FOLLICLES 
furrow 
OF SKIN 
Fig. 782.-The furrows of the skin and the areas which these furrows delimit, reproduced from an impression of 
the dorsal surface of the wrist. (Toldt.) 
The Deep or Reticular Layer or Tunica Propria (stratum reticular e) rests upon 
the subcutaneous tissue. It passes superficially into the papillary layer, and at 
most places into the subcutaneous tissue without a sharp line of differentiation. 
At some places, for instance in the nipple, the deep layer of the corium rests 
upon a layer of muscular fibre. In the face this muscle-fibre is striated and sends 
FURROWS OF SKI N 
RIDGES OF SKIN 
TOUCH CORPUSCLE' 
ORIFICE OF 
SUDORIFEROUS 
DUCT 
EPIDERMIS 
STRATUM CORNEUS 
STRATUM LUCIDUM 
RETE MUCOSUM 
SUDORI FEROUS 
DUCT 
CAPILLARY 
LOOP OF 
PAPI LLXE 
CORIUM 
STRATUM PAPILLARE 
STRATUM RETICULARE 
BLOODVESSELS 
OF CORIUM 
BODY OF 
SUDORI FEROUS 
GLAN D 
SUBCUTANEOUS 
AREOLAR TISSUE 
Fig. 783.-Vertical section through the skin of the finger-tip. The layers of the epidermis and of the corium. 
The subcutaneous areolar tissue. The sudoriferous or sweat-gland. (Toldt.) 
prolongations to the papillary layer; in the nipple and scrotum it is non-striated. 
The reticular layer is composed of bundles of white fibrous tissue, arranged in a 
network. In the meshes of the network are fat, blood-vessels, lymphatics, seba- 
ceous glands, sweat-glands, and hair-follicles. 
The Subcutaneous Areolar Tissue or Tela Subcutanea (panniculus adiposus) con- 
nects, the skin to the parts beneath; it is composed of bundles of connective tissue THE SKIN 
1181 
which cross repeatedly and form spaces. In almost all regions thespaces containfat, 
but in the scrotum and external ear they do not contain fat. When the connective- 
tissue fibres of the panniculus adiposus are long and nearly parallel to the skin- 
surface the skin becomes wrinkled; when they are short and nearly at right angles 
to the surface, the skin cannot wrinkle. 
The Superficial or Papillary Layer or Corpus Papillare of the Corium {stratum papil- 
lare) lies just beneath the epidermis, contains the papillae, and is composed of a 
network of fine bundles of fibrous tissue. The papillae are composed of fine 
strands of connective tissue and elastic 
tissue. They project from the corium 
beneath the epidermis and enter into 
depressions of the epidermis. They vary 
greatly in size, averaging of an inch 
in height and yiy of an inch in width at 
the base. In the face, especially in the 
eyelids, they are insignificant. On the 
glans penis, the palms of the hands, and 
the soles of the feet, and in the nipples, 
they are large. In the palmar surfaces 
of the hands and fingers and the plantar 
surfaces of the feet and toes they pro- 
duce permanent ridges (Fig.785). A ridge 
is composed of two or more rows of 
papillae, and the ducts of sweat-glands 
emerge between rows of papillae, and 
open on the curved surface ridges (Fig. 
785). Most of the papillae contain loops of capillaries, and are called vascular 
papillae. Some contain nerve-terminations and are called nervous papillae. Be- 
tween the papillary layer of the corium and the epidermis is a very thin and 
structureless membrane called the basal membrane. 
ARRECTOR 
PILI MUSCLE 
HAIR- 
FOLLICLE 
CORIUM 
EPIDERM IS 
SUDORIFEROUS 
GLAN DS 
SUBCUTANEOUS 
AREOLAR TISSUE 
Fig. 784.-Vertical section through the skin of the 
trunk in the region of the arch of the ribs. One of 
the small hairs is seen in longitudinal section. (Toldt.) 
PAPILLAE OF. 
CORIUM 
RIDGES OF 
SKIN 
SUDORIFEROUS 
DUCTS 
FURROWS 
OF SKIN 
Fig. 785.-The furrows and ridges of true skin on the palmar surface of one of the fingers, the epidermis 
having been removed. (Toldt.) 
The Cuticle, Scarf Skin or Epidermis (Figs. 783, 784, 786, and 787).-The 
cuticle, scarf skin or epidermis is composed of layers of epithelium and is 
derived from the ectoderm. The epithelium is stratified, and there are no 
blood-vessels. Two layers can be readily made out, the superficial or horny- 
layer and the deeper or Malpighian layer. 
The Horny Layer (stratum corneum).-The horny layer is formed by several 
layers of non-nucleated scaly cells. The cells consist of keratin. The surface 
cells of the horny layers are being constantly rubbed off, and are being replaced 
by cells from the Malpighian layer, which'are converted into keratin as they near 
the surface. 1182 
THE ORGANS OF SPECIAL SENSE 
The Malpighian Layer.-The Malpighian layer of the epidermis is divided into 
four layers, named, from without inward, the stratum lucidum, the stratum granu- 
losum, the stratum mucosum, and the stratum germinativum. 
The Stratum Lucidum is not classified by all writers as part of the Malpighian 
layer. Some anatomists classify it as a separate layer. It is here regarded as the 
most superficial part of the Malpighian layer. It consists of several layers of flat 
cells, the nuclei of which are beginning to disappear. The cells contain eleidin 
granules. In regions where the epidermis is thin the stratum lucidum is absent. 
The Stratum Granulosum consists of several layers of nucleated flat cells, con- 
taining keratohyaline granules. These granules are probably formed from the 
disintegrating nucleus, and in the stratum lucidum are converted into eleidin. 
Hairs 
Superficial 
layers 
Rete 
Epidermis 
or 
Cuticle 
Mucosum 
Papilla 
Curium 
Derma 
or 
Cutis 
Fat-Cells. 
Sub- 
cutaneous 
* Cellular 
tissue 
Fibrous 
tissue 
Sweat-Glands 
Sebaceous 
Glands 
Nutrient Artery 
Fio 786.-A sectional view of the skin (magnified). 
The Mucous Layer, the Stratum Spinosum or the Stratum Mucosum consists of 
numerous layers of nucleated, polygonal, spine-shaped cells known as prickle cells 
or finger cells. Between the cells of the stratum mucosum are spaces containing 
pigment granules and leukocytes. Processes from the prickle-cells join adjacent 
cells. This layer contains numerous connective-tissue fibres arranged in a net- 
work, and known as epidermic fibrils. 
The Stratum Cylindricum or Stratum Germinativum is composed of cylindrical or 
prickle-cells, the points of which are directed downward. Fine fibrils pass up 
from the corium between the cells, and there is cement-substance as well between 
them. 
Pigmentation of the Skin.-As previously stated, in certain regions the skin of the 
white race is brown because of pigmentation (areolae, nipples, around the anus, 
axillae, scrotum, labia majora). This is due to pigment within the epithelial and THE SKIN 
1183 
connective-tissue cells of the papillary layer of the corium, and in the basal cells 
of the epidermis. There are few or none of these pigmented cells in the stratum 
corneum of one of the Caucasian race. 
Stratum corneum. 
Stratum lucidum. 
Stratum granulosum 
Stratum mucosum 
Malpighii. 
■Nerve-fibrils. 
Stratum germinativum. 
Fig. 787.-Section of epidermis. (Ranvier.) 
" In negroes and other colored races the deep pigmentation is due to a similar 
distribution of the pigment granules in the entire epidermis; but even here the 
pigmentation decreases toward the surface, although the uppermost cells of the 
Fig. 788.-Microscopic section of skin, showing the epidermis and derma ; a hair in its follicle ; 
the Erector pili muscle ; sebaceous and sudoriferous glands. 
stratum corneum always contain some pigment. The nuclei of the cells are always 
free from coloring matter. The question as to the origin of the pigment is as yet 
unsolved."1 
' A Text-book of Histology. By A. A. Bohm and M. von Davidoff. Translated and edited by G. Carl Huber. 1184 
THE ORGANS OF SPECIAL SENSE 
The Arteries and Veins of the Skin (Fig. 789).-The arteries supplying the skin 
vary in number, and vary much in size, being largest in regions exposed to 
pressure, as the skin of the palms, soles, and buttocks. The arteries enter the 
skin from a network in the subcutaneous tissue, and by an anastomosis in the 
deepest part of the corium form a network (rete arteriosum cutaneum). The vessels 
send branches to the fat and to the sweat-glands. Branches from the network just 
described ascend and form a second network in the corium beneath the papillae. 
This is called the subpapillary network (rete arteriosumsubpapillare}. From this net- 
work fine capillary vessels pass into the papillae, forming, in the smaller papillae, 
a single capillary loop, but in the larger a more or less convoluted vessel. From 
this network branches go to the hair-follicles and sebaceous glands. The blood 
from the papillae passes into a plexus (rete venosum) beneath the papillae. This 
communicates with another plexus (rete venosum), between the corium and sub- 
RETE 
VENOSUM 
SUBPAPI LLARY 
N ETWORK 
EPIDERM IS 
PAPILLARY LAYER 
RETE 
VENOSUM 
RETICULAR LAYER 
CORIUM 
RETE ARTERIOSUM 
CUTANEUM 
SUBCUTANEOUS 
TISSUE 
Fig. 789.-The distribution of the blood-vessels in the skin of the sole of the foot (Spalteholz ) 
RETE 
VENOSUM 
cutaneous tissue. In some regions one or more retia are interposed between these 
two. The veins from the sweat-glands, sebaceous glands, superficial fat, and hair- 
follicles are received by the retia venosa. From the deepest rete veins pass to the 
subcutaneous tissue, and these veins enter the large subcutaneous veins. 
The Lymphatics of the Skin.-There are numerous lymphatics supplied to the 
skin which form two networks, superficial and deep, communicating with each 
other and with the lymphatics of the subcutaneous tissue by oblique branches. 
They originate in the cell-spaces of the tissue. 
The Nerves of the Skin.-The nerves of the skin terminate partly in the epidermis 
(Figs. 783 and 787) and partly in the cutis vera (Fig. 783). The former are pro- 
longed into the epidermis from a dense plexus in the superficial layer of the corium 
and terminate between the cells in bulbous extremities; or, according to some 
observers, in the deep epithelial cells themselves. The latter terminate in end- 
bulbs, touch-corpuscles, or Pacinian bodies (Fig. 783), in the manner already 
described; and, in addition to these, a considerable number of fibrils are distrib- 
uted to the hair-follicles, which are said to entwine about the follicle in a circular THE NAILS 
1185 
manner. Other nerve-fibres are supplied to the plain muscular fibres of the hair- 
follicles (arrectores pili) and to the muscular coat of the blood-vessels. These are 
probably non-medullated fibres. 
The Appendages of the Skin. 
Fhe appendages of the skin are the nails, the hairs, the sudoriferous and seba- 
ceous glands, and their ducts. 
The nails and hairs are peculiar modifications of the epidermis, consisting 
essentially of the same cellular structure as that tissue. 
Stratum 
corneum. 
'Stratum 
granulosum. 
-Corium. 
Blood-vessel. 
Eponycilium. 
Nail. 
Stratum 
Malpighii: 
Stratum corneum 
of the nail 
groove. 
Fig. 790.-Longitudinal section through human nail and its nail groove (sulcus). (From Bohm and 
Davidoff's Histology. 
The Nails (ungues) (Figs. 790, 791,792, 793, 794, and 795).-The nails are flat- 
tened, elastic structures of a horny texture, placed upon the dorsal surface of the 
terminal phalanges of the fingers and toes. Each nail is convex on its outer sur- 
face, concave within. Its chief mass, called the body (corpus unguis), lies upon 
the nail-bed. The free edge is called the margo liber. Each lateral margin (margo 
lateralis), like the proximal short edge of the nail (margo occultus), lies in a groove 
of the cutis, the ungual fold (sulcus matricis unguis). The ungual wall (vallum 
unguis) overlies the lateral and posterior edges. The nail is implanted by means 
of a portion, called the root {radix unguis), into a groove in the skin. The root is 
beneath the ungual wall and is composed of cells which have not yet become 
Nail. 
Stratum Malpighii.' 
Nail wail.. 
Nail grooves 
Corium. 
Blood-vessel. 
Fig. 791.-Transverse section through human nail and its sulcus. (From Bohm and Davidoff's Histology.) 
horny. It is white in color. The nail has a very firm adhesion to the cutis vera, 
being accurately moulded upon the surface of the true skin, as the epidermis is in 
other parts. The part of the cutis beneath the body and root of the nail is called 
the matrix (matrix unguis), because it is the part from which the nail is produced. 
Corresponding to the body of the nail, the matrix is thick, and raised into a series 
of longitudinal ridges (cristae matricis unguis), which are very vascular, and the 
color is seen through the transparent tissue. Behind this, near the root of the 
nail, the papillae are small, less vascular, and have no regular arrangement, and 
here the tissue of the nail is somewhat more opaque; hence this portion is of a 
whiter color, and is called the lunula on account of its crescentic shape. 1186 
THE ORGANS OF SPECIAL SENSE 
The cuticle, as it passes forward on the dorsal surface of the finger or toe, is 
attached to the surface of the nail, a little in advance of the nail root; at the 
extremity of the finger it is connected with the under surface of the nail a little 
behind its free edge. The cuticle and the horny substance of the nail (both epi- 
dermic structures) are thus directly continuous with each other. The nails con- 
sist of a greatly thickened stratum lucidum, the stratum corneum forming merely 
BODY 
HORNY 
LAYER 
RIDGES OF 
MATRIX1 
MALPIGHIAN 
LAYER 
NAIL-WALL 
MATRIX 
SULCUS OF 
MATRIX 
LATERAL 
MARGIN 
THIRD 
PHALANX 
PERIOSTEUM^ 
RETINACULA 
OF SKIN 
RIDGES^ 
OF SKIN 
Fig. 792.-Transverse section through the nail and the terminal portion of the ring finger. (Toldt.) 
PALMAR SURFACE 
OF FINGER 
the thin cuticular fold (eponychium) which overlaps the lunula. The cells have 
a laminated arrangement, and are essentially similar to those composing the 
epidermis. The deepest layer of cells, which lie in contact with the papillae 
of the matrix, are columnar in form and arranged perpendicularly to the surface; 
those which succeed them are of a rounded or polygonal form, the more superficial 
ones becoming broad, thin, and flattened, and so closely compacted as to make the 
MATRIX OF NAIL 
RIDGES OF 
MATRIX: 
FREE EDGE 
BODY 
SULCUS OF 
MATRIX" 
NAIL WALL> 
LATERAL 
MARGIN 
LATERAL 
MARGIN 
NAIL FOLD 
ROOT 
LUNULA 
SULCUS OF. 
MATRIX 
CONCEALED MARGIN 
Fig 794.-The matrix of 
the nail or nail-bed, with the 
nail-fold and nail-walls dis- 
played by the removal of the 
epidermic portion of the nail 
or nail proper and the sur- 
rounding epidermis. (Toldt ) 
Fig. 795.-Matrix of the 
nail with partly opened mar- 
ginal groove of the nail-bed. 
(Toldt.) 
Fig. 793.-The finger nail com- 
pletely isolated, seen from the con- 
vex side. (Toldt.) 
limits of each cell very indistinct. It is by the successive growth of new cells at 
the root and under surface of the body of the nail that it advances forward and 
maintains a due thickness, while, at the same time, the growth of the nail in the 
proper direction is secured. As these cells in their turn become displaced by 
the growth of new ones, they assume a flattened form, and finally become closely 
compacted together into a firm, dense, horny texture. In chemical composition the THE HAIRS 
1187 
nails resemble the upper layers of the epidermis, containing, however, a some- 
what larger proportion of carbon and sulphur (Mulder). 
The Hairs (piZi)(Figs. 784,786, 788, 796,797, and 798).-The hairs are peculiar 
modifications of the epidermis, and consist essentially of the same structure as 
that membrane. They are found on nearly every part of the surface of the body, 
excepting the palms of the hands, soles of the feet, the vermilion borders of the 
lips, the dorsal surfaces of the phalanges, the nipples, the inner surface of the 
prepuce, and the glans penis. Hairs include hairs of the head (capilia); of the eye- 
brows (supercilia); of the beard (barba); of the ears (tragi); of the nostrils (vibrissae); 
the eyelashes (cilia)', hairs of the axilla (hirci); pubes (pubes); and the small hairs 
of the skin or woolly hairs (lanugo). 
They vary much in length, thick- 
ness, and color in different parts of 
the body and in different races of 
mankind. In some parts, as in the 
skin of the eyelids, they are so short 
as not to project beyond the follicles 
containing them; in others, as upon 
the scalp, they are of considerable 
length; again, in other parts, as the 
eyelashes, the hairs of the pubic re- 
gion, and the whiskers and beard, 
they are remarkable for their thick- 
ness. Straight hairs are stronger 
than curly hairs, and present on 
transverse section a cylindrical or 
oval outline; curly hairs, on the 
other hand, are flattened. The hairs 
are usually oblique to the surface 
from which they arise (Fig. 784). 
Their direction depends upon the 
region from which they spring, being 
fairly regular in certain regions. 
'Thus are formed hair-streams (Ru- 
mina pilorum) and hair-whirlpools 
(vortices pilorum). 
A hair consists of the root, the 
part implanted in the skin; the shaft 
or stem, the portion projecting from 
its surface; and the point. 
The Root of the Hair (radix pili) 
presents at its extremity a bulbous 
enlargement, the hair-bulb (bulbus 
pili)(Figs.786 and 796),which is whiter in color and softer in texture than the shaft, 
and is lodged in a follicular involution of the epidermis called the hair-follicle (folh- 
culus pili)(Figs. 784 and 788). When the hair is of considerable length the follicle 
extends into the subcutaneous cellular tissue (Fig. 786). The hair-follicle com- 
mences on the surface of the skin with a funnel-shaped opening, and passes inward 
in an oblique or curved direction-the latter in curly hair-to become dilated at 
its deep extremity or fundus (fundus folliculi pili), where it corresponds with the 
bulbous condition of the hair which it contains. It has opening into it, near its 
free extremity, the orifices of the ducts of one or more sebaceous glands (Figs. 
786, 788, 796, and 797). At the bottom of each hair-follicle is a small conical, 
vascular eminence or papilla, the hair-papilla (papilla pili) (Figs. 796 and 797), 
SHAFT- 
FIBROUS 
"SUBSTANCE 
MEDULLARY 
SUBSTANCE 
NECK OF. 
HAIR-FOLLICLE 
INNER 
ROOT-SHEATH 
SEBACEOUS 
GLAND 
OUTER 
ROOT-SHEATH' 
ROOT* 
OUTER 
FIBROUS LAYER 
.arrector 
PILI MUSCLE 
INNER 
FIBROUS LAVER' 
HYALINE 
LAYER 
HAIR-BULB,. 
HAIR-PAPILLA 
FUNDUS OF 
HAIR-FOLLICLE 
Fig. 796.-A hair of the head still in the course of growth, 
with hair-bulb in longitudinal section (Toldt.) THE ORGANS OF SPECIAL SENSE 
1188 
similar in every respect to the papillae found upon the surface of the skin; it is 
continuous with the dermic layer of the follicle, is highly vascular, and is prob- 
ably supplied with nervous fibrils. In structure the hair-follicle consists of two 
coats-an outer or dermic, and an inner or epidermic (Figs. 796 and 798). 
The Outer or Dermic Coat is formed mainly of fibrous tissue; it is continuous 
with the corium, is highly vascular, and is supplied by numerous minute nervous 
filaments. It consists of three layers. The most internal, the cuticular lining 
of the follicle, consists of a hyaline basement-membrane, the hyaline layer, having 
a glassy, transparent appearance, which is well marked in the larger hair-follicles, 
but is not very distinct in the follicles of minute hairs. It is continuous with the 
basement-membrane of the surface of the corium. External to this is the inner 
fibrous layer, a compact layer of fibres and spindle-shaped cells arranged circularly 
around the follicle. This layer extends from the bottom of the follicle as high as 
the entrance of the ducts of the sebaceous glands. Externally is the outer fibrous 
layer, a thick layer of connective tissue, arranged in longitudinal bundles, forming 
a more open texture and corresponding to the reticular part of the corium. In this 
are contained the blood-vessels and nerves. 
EPIDERM IS- 
S H A FT 
ARRECTOR 
PILI MUSCLE 
SEBACEOUS 
GLAN D 
SUDORIFEROUS 
'gland 
CORIUM 
-HAIR-FOLLICLE 
ROOT 
SUBCUTANEOUS 
AREOLAR TISSUE 
HAIR-KNOB 
HAIR-BULB 
RETI NACULA 
OF SKIN 
PAPILLA 
OF HAIR 
OCCI PITO-FRONTAL 
APON EUROSIS 
Fig. 797.-Vertical section through the skin of the head. The hairs of the head in longitudinal section. (Toldt.) 
The Inner or Epidermic Layer is closely adherent to the root of the hair, so that 
when the hair is plucked from its follicle this layer most commonly adheres 
to it and forms what is called the root-sheath. It consists of two strata, named 
respectively the outer and inner root-sheaths; the former of these corresponds with 
the Malpighian layer of the epidermis, and resembles it in the rounded form and 
soft character of its cells; at the bottom of the hair-follicle these cells become con- 
tinuous with those of the root of the hair. The inner root-sheath consists of a 
delicate cuticle next the hair, composed of a thin layer of imbricated scales having 
a downward direction, so that they fit accurately over the upwardly directed 
imbricated scales of the hair itself; then of one or two layers of hornv, flattened 
nucleated cells, known as Huxley's layer; and finally of a single layer of horny 
oblong cells without visible nuclei, called Henle's layer. 
The hair-follicle contains the root of the hair, which terminates in a bulbous 
extremity, and is excavated so as to exactly fit the papilla from which it grows. 
The bulb is composed of polyhedral epithelial cells, which as they pass upward 
into the root of the hair become elongated and spindle-shaped, except some in the 
centre which remain polyhedral. Some of these latter cells contain pigment- THE HAIRS 
1189 
granules, which give rise to the color of the hair. It occasionally happens that 
these pigment-granules completely fill the cells of the medullary substance in 
the centre of the bulb, which gives rise to the dark tract of pigment often found, 
of greater or less length, in the axis of the hair. 
The Stem or Shaft of the Hair (scapus pili) (Fig. 796), consists of a central pith or 
medulla, the fibrous part of the hair, and the true cuticle externally. The medulla 
(substantia medullaris pili) occupies the centre of the shaft and ceases toward the 
point of the hair. It is usually wanting in the fine hairs covering the surface of 
the body, and commonly in those of the head. It is found in the shafts of all thick 
hairs and in the deeper parts of the root of most hairs. It is more opaque and 
deeper colored when viewed by transmitted light than the fibrous part; but when 
viewed by reflected light it is white. It is composed of rows of polyhedral cells, 
which contain granules of eleidin and frequently air-bubbles. The fibrous portion 
or cortical substance of the hair (substantia corticalis pili) constitutes the chief part 
of the shaft; its cells are elongated and unite to form flattened fusiform fibres. 
Between the fibres are found minute spaces which contain either pigment-granules 
in dark hair or minute air-bubbles in white hair. In addition to this there is also a 
CUTICLE OF 
ROOT-SHEATH 
HYALINE 
LAYER 
HENLE'S 
LAYER 
INNER 
FIBROUS ' 
LAYER 
HUXLEY'S 
LAYER 
OUTER 
FIBROUS 
LAYER 
OUTER 
ROOT-SH EATH 
INNER 
ROOT-SHEATH 
MEDULLARY 
SUBSTANCE 
FIBROUS 
SUBSTANCE 
Fig. 798.-A moustache hair with its hair-follicle in transverse section. (Toldt.) 
diffused pigment contained in the fibres. The cells which form the outer hair mem- 
brane or true cuticle {cuticula pili) consist of a single layer which surrounds those of 
the fibrous part; they are converted into thin, flat scales, having an imbricated 
arrangement. 
Connected with the hair-follicles are minute bundles of involuntary muscular 
fibres, termed arrectores pili (mm. arrectores pilorum) (Figs. 784 and 796). They 
arise from the superficial layer of the corium, and are inserted into the outer 
surface of the hair-follicle, below the entrance of the duct of the sebaceous gland. 
They are placed on the side toward which the hair slopes, and by their action 
elevate the hair.1 When the hair is elevated a depression forms over the seat of 
origin of the muscle, and the parts about the hair are elevated. This condition is 
known as goose-skin. It is probable that the contraction of these muscles aids in 
emptying sebaceous glands. 
Blood-vessels and Nerves (Fig. 786).-A hair-follicle possesses a rich network of 
capillaries about the hyaline membrane, and capillary loops pass to the papilla. 
' Arthur Thomson suggests that the contraction of these muscles on follicles which contain weak, flat hairs 
will tend to produce a permanent curve in the follicle, and this curve will be impressed on the hair which is 
moulded within it, so that the hair, on emerging through the skin, will be curled. Curved hair-follicles are 
characteristic of the scalp of the Bushman.-Ed. of 15th English edition. THE ORGANS OF SPECIAL SENSE 
1190 
We have little knowledge as to nerve-terminations of the human hair. "In other 
mammals the nerves end below the sebaceous glands. Medullated fibres lose 
their medullary sheaths, divide, and penetrate to the hyaline membrane. Here 
some of the branches encircle the hair, while others end freely on the hyaline 
membrane as naked axis-cylinders. These branch regularly and run parallel to 
the long axis of the hair.''1 
The Sudoriferous or Sweat-glands (glandulae sudorijerae) (Figs. 783, 7S4, 786, 
788, and 797).-The sudoriferous or sweat-glands are the organs by which a large 
portion of the aqueous and gaseous materials is excreted by the skin. They are 
found in almost every part of this structure, being absent on the red border of the 
lips, the glans penis, and inner surface of the prepuce. On the eyelids they are some- 
what modified, and are called ciliary glands (glandidae ciliares [Molli]); about the 
anus they are extremely large, and are called circumanal glands (glandulae circum- 
anales). The sweat-glands are situated in small pits below the under surface of the 
corium, or, more frequently, in the subcutaneous areolar tissue, surrounded by a 
quantity of adipose tissue. They are small, lobular, reddish bodies, consisting of 
a single convoluted tube, from which the efferent duct (ductus sudorijerus) proceeds 
upward through the corium and cuticle. The duct in the corium has true walls; in 
the epidermis it has not individual walls, but is simply an epidermic tube. It 
becomes somewhat dilated at its extremity, and opens on the surface of the cuticle by 
an oblique valve-like aperture (porus sudorijerus). The duct, as it passes through 
the epidermis, presents a spiral arrangement, being twisted like a corkscrew, in 
those parts where the epidermis is thick; where, however, the epidermis is thin, the 
spiial arrangement does not exist. In the superficial layers of the corium the duct 
is straight, but in the deeper layers it is convoluted or even twisted. The spiral 
course of these ducts is especially distinct in the thick cuticle of the palm of the 
hand and sole of the foot, rhe size of the glands varies. They are especially 
large in those regions where the flow of perspiration is copious, as in the 
axillae, where they form a thin, mamillated layer of a reddish color, which 
corresponds exactly to the situation of the hair in this region; they are large also in 
the groin. Their number varies. They are most numerous on the palm of the hand, 
presenting, according to Krause, 2800 orifices on a square inch of the integument, 
and are rather less numerous on the sole of the foot. In both of these situations 
the orifices of the ducts are exceedingly regular, and open on the curved surface 
ridges. In other situations they are more irregularly scattered, but the number 
in a given extent of surface presents a fairly uniform average. In the neck and 
back they are least numerous, their number amounting to 417 on the square inch 
(Krause). Their total number is estimated by the same writer at 2,381,248, and, 
supposing the aperture of each gland to represent a surface of of a line in 
diameter, he calculates that the whole of these glands would present an evap- 
orating surface of about eight square inches. Each gland consists of a single 
tube intricately convoluted, terminating at one end by a blind extremity, and 
opening at the other end upon the surface of the skin. 
The wall of the tubercle of the secreting coil is lined with cubical epithelial 
cells, external to these is a layer of smooth muscle-cells, and more externally a 
layer of connective tissue, the membrana propria. The duct in the corium, in 
contrast to the secreting coil, has no layer of muscle-cells, but instead a second 
layer of epithelial cells covered by connective tissue. As previously stated, the 
duct becomes spiral in the epidermis, its own wall disappears, and the channel 
is bounded by epidermic cells. 
Blood-vessels and Nerves.-The blood-vessels are branches from the subcuta- 
neous vessels and the arterial plexus of the deep part of the corium. Numerous 
1 Histology and Microscopic Anatomy. By Dr. Ladislaus Szymonowicz. Translated and edited by John 
Bruce MacCallum, M.D. THE SEBACEOUS GLANDS 
1191 
non-medullated nerve-fibres lie upon the membrana propria of a sweat-gland. 
From them fibrils pass inward and terminate by end-bulbs upon the cells of the 
gland. 
The Sebaceous Glands (glandulae sebaceae).-The sebaceous glands are small, 
sacculated, glandular organs, lodged in the substance of the corium. They are 
found in most parts of the skin, and are usually connected with hair-follicles. 
This connection is so common that they are sometimes called hair-follicle glands. 
'They are found in some regions which are devoid of hairs-the vermilion borders 
of the lips, the labia minora, the glans penis, and prepuce. These glands are espe- 
cially abundant in the scalp and face; they are also very numerous around the 
apertures of the anus, nose, mouth, and external ear; but are wanting in the palms 
of the hands and soles of the feet. Each gland consists of a single duct, more or 
less capacious, which terminates in a cluster of small secreting pouches or saccules. 
The sacculi connected with each duct vary, in number, as a rule, from two to five, 
but in some instances may be as many as twenty. They are composed of a trans- 
parent, colorless membrane, enclosing a number of epithelial cells. Those of 
the outer or marginal layer are small and polyhedral, and are continuous with 
the lining cells of the duct. The remainder of the sac is filled with larger cells, 
containing fat, except in the centre, where the cells have become broken up, leav- 
ing a cavity containing their debris and a mass of fatty matter, which constitutes 
the sebaceous secretion. The orifices of the ducts open most frequently into the 
hair-follicles, but occasionally upon the general surface, as in the labia minora and 
the free margins of the lips. On the nose and face the glands are of large size, 
distinctly tabulated, and often become much enlarged from the accumulation of 
pent-up secretion. The largest sebaceous glands are those found in the eyelids- 
the Meibomian glands. THE ORGANS OF DIGESTION. 
qiHE Apparatus for the Digestion of the Food (apparatus digestorius) consists 
I of the alimentary canal and of certain accessory organs. 
THE ALIMENTARY CANAL. 
The alimentary canal is a musculo-membranous tube, about thirty feet in 
length, extending from the mouth to the anus, and lined throughout its entire 
extent by mucous membrane. It has received different names in the various parts 
of its course; at its commencement, the mouth, we find provision made for the 
mechanical division of the food (mastication), and for its admixture with a fluid 
secreted by the salivary glands (insalivation); beyond this are the pharynx and 
the oesophagus, the organs which convey the food (deglutition) into that part of 
the alimentary canal, the stomach, in which the principal chemical changes occur, 
and in which the reduction and solution of the food take place; in the small intes- 
tines the nutritive principles of the food, the chyle, are separated, by its admixture 
with the bile, pancreatic and intestinal fluids, from that portion which passes into 
the large intestine, most of which is expelled from the system. 
Alimentary Canal, 
Duodenum. 
Jejunum. 
Ileum. 
Mouth. 
Small intestine 
Pharynx. 
Oesophagus. 
Stomach. 
Caecum. 
Colon. 
Rectum. 
Large intestine 
A ccessory 0 rgans. 
Teeth. 
Salivary glands 
Parotid. 
Submaxillary. 
Sublingual. 
Liver. 
Pancreas. 
Spleen. 
THE MOUTH, ORAL OR BUCCAL CAVITY (CAVUM ORIS). 
The mouth is placed at the commencement of the alimentary canal; it is a 
nearly oval-shaped cavity, in which the mastication and insalivation of the food 
take place (Figs. 799, 818, and 824). 
The aperture of the mouth (rima oris) is bounded by the lips. The angle of the 
mouth (angulus oris) is formed on each side by the meeting of the upper and 
lower lips (commissura labiorum). When at rest with the lips in contact, the rima 
is a slightly curved line. Every movement which the lips make alters the shape 
of the rima. When the mouth is closed the floor and roof are usually in contact 
and its sides are approximated to the dental arches. The mouth consists of two 
1193 1194 
THE ORGANS OF DIGESTION 
parts: an outer, smaller portion, the vestibule, and an inner, larger part, the cavity 
proper of the mouth. 
The Vestibule (vestibulum oris).-The vestibule is a slit-like space, bounded 
in front and laterally by the lips and cheeks; behind and internally by the gums 
and teeth. Above and below it is limited 
by the reflection of the mucous membrane 
from the lips and cheeks to the gum cover- 
ing the upper and lower alveolar arch re- 
spectively. It receives the secretion from the 
parotid glands, and communicates, when the 
jaws are closed, with the cavum oris by an 
aperture on each side behind the wisdom 
teeth. 
The Cavity of the Mouth Proper (cavum 
oris proprium).-The cavity of the mouth 
proper is bounded laterally and in front 
by the alveolar arches with their contained 
teeth ; behind it communicates with the 
pharynx by a constricted aperture termed 
the isthmus faucium. It is roofed in by the 
hard and soft palate. The greater part of the 
floor is formed by the tongue, the remainder 
being completed by the reflection of the mu- 
cous membrane from the sides and under 
surface of the tongue to the gum lining the 
inner aspect of the mandible. It receives 
the secretion from the submaxillary and 
sublingual glands. 
The Mucous Membrane. - The mucous 
membrane lining the mouth is continuous 
with the integument at the free margin of 
the lips and with the mucous lining of the 
pharynx behind; it is of a rose-pink tinge 
during life, and very thick where it covers the hard parts bounding the cavity. 
It is covered by stratified epithelium. 
MOUTH 
SALIVARY 
GLANDS 
PHARYNX 
LIVER 
-GULLET 
STOMACH 
PANCREAS 
large 
intestine 
SMALL 
INTESTINE 
Fig. 799.-Diagram of the alimentary tube and 
its appendages. (Testut.) 
ANUS 
The Lips (Labia Oris). 
The lips are two fleshy folds which surround the orifice of the mouth, formed 
externally by integument and internally by mucous membrane, between which are 
found the Orbicularis oris muscle (Fig. 263), the coronary vessels (Fig. 395), some 
nerves (Fig. 395), areolar tissue, and fat, and numerous small labial glands. 
The upper lip is called the labium superius; the lower lip is called the labium 
inferius. The inner surface of each lip is connected in the middle line to the gum 
of the corresponding jaw by a fold of mucous membrane, the frenulum (frenulum 
labii superioris and frenulum labii inferioris). The frenulum labii superioris is 
the larger of the two. On each side, external to the angle of the mouth, the lips 
become continuous (commissura labiorum). 
The Labial Glands (glandulae labiates} (Fig. 395).-The labial glands are situated 
between the mucous membrane and the Orbicularis oris muscle around the orifice 
of the mouth. They are rounded in form, about the size of small peas, and their 
ducts open by minute orifices upon the mucous membrane. In structure they 
resemble the salivary glands. THE TEETH 
1195 
The Cheeks (Buccae). 
The cheeks form the sides of the face and are continuous in front with the lips. 
They are composed externally of integument, internally of mucous membrane, 
and between the two of a muscular stratum, besides a large quantity of fat, areolar 
tissue, vessels, nerves, and buccal glands. 
The Mucous Membrane.-The mucous membrane lining the cheek is reflected 
above and below upon the gums, where its color becomes lighter; it is continuous 
behind with the lining membrane of the soft palate. Opposite the second molar 
tooth of the upper jaw is a papilla, the summit of which presents the aperture of 
the duct of the parotid gland (ductus parotideus [S/enonw]) (Fig. 824.) The prin- 
cipal muscle of the cheek is the Buccinator, but numerous other muscles enter into 
its formation-viz., the Zygomatici, Risorius Santorini, and Platysma myoides. 
The Buccal Glands (glandulae buccales}.-The buccal glands are placed in the 
submucous tissue between the mucous membrane and Buccinator muscle; they 
are similar in structure to the labial glands, but smaller. Four or five glands of 
larger size than the previously mentioned glands are placed beneath the mucous 
membrane in the neighborhood of the last molar tooth. They are called the 
molar glands (glandulae molares}. Their ducts open into the mouth opposite the 
last molar tooth. 
The Gums (Gingiva). 
The gums are composed of a dense fibrous tissue closely connected to the 
periosteum of the alveolar processes and surrounding the necks of the teeth. They 
are covered by smooth and vascular mucous membrane, which is remarkable for 
its limited sensibility. Around the necks of the teeth this membrane presents 
numerous fine papillae; and from this point it is reflected into the alveolus, where 
it is continuous with the periosteal membrane lining that cavity. 
The Teeth (Dentes). 
The human subject is provided with two sets of teeth, which make their appear- 
ance at different periods of life. The first set appear in childhood, and are called 
the temporary, deciduous or milk teeth. The second set are named permanent. 
The temporary teeth are twenty in number-four incisors, two canine, and four 
molars in each jaw (Figs. 800 and 817). 
The permanent teeth are thirty-two in number-four incisors (two central and two 
lateral), two canines, four bicuspids, and six molars in each jaw (Figs. 802 and 806). 
General Characters (Fig. 807).-Each tooth consists of three portions; the 
crown or body (corona dentis}, projecting above the gum; the root or fang (radix 
dentis}, entirely concealed within the alveolus; and the neck (collum dentis}, the 
constricted portion, between the root and crown. 
Surfaces.-The surfaces of a tooth are named thus: that which comes in con- 
tact with the teeth of the opposite jaw is the grinding or masticating surface (facies 
masticatoria}; that which touches the next tooth in the same row is the contact 
surface (facies contactus}. That surface which is toward its predecessor is called 
the proximal surface (in incisors and canines, facies medialis; in molars and pre- 
molars, facies anterior}. That surface which is toward its successor is called the 
distal surface (in incisors and canines, facies lateralis; in molars and premolars, 
facies posterior}. That which looks toward the lips and cheek is the labial or 
buccal surface (facies labialis}. 'That toward the tongue is the lingual surface 
(facies lingualis}. In part this method of designation applies to the roots as well 
as to the crowns of teeth. THE ORGANS OF DIGESTION 
1196 
The Roots of the Teeth.-The roots of the teeth are firmly implanted within the 
sockets or alveoli of the jaws (alveoli dentales) (see pp. 109 and 124). These depres- 
sions are lined with periosteum, called the pericementum, which is reflected on to the 
tooth at the point of the root and covers it as far as the neck. This is the root 
membrane (periosteum alveolare). At the margin of the alveolus the periosteum 
becomes continuous with the fibrous structure of the gums. 
Right upper. 
Lower. 
Fig. 800.-Deciduous teeth. Left side. 
Fig. 801.-Deciduous teeth. Lingual view. 
Temporary, Deciduous or Milk Teeth (dentes decidui)(Figs. 800,801, and 817). 
-The temporary or milk teeth are smaller, but resemble in form those of the per- 
manent set. The neck is more marked, owing to the greater degree of convexity 
of the labial and lingual surfaces of the crown. The hinder of the two temporary 
molars is the largest of all the deciduous teeth, and is succeeded by the second 
bicuspid, rhe first upper molar has only three cusps-two labial, one lingual; the 
second upper molar has four cusps. The first lower molar has four cusps; the 
second lower molar has five. The roots of the temporary molar teeth are smaller 
and more diverging than those of the permanent set, but in other respects bear a 
strong resemblance to them. 
Fig. 802.-Permanent teeth, right side. (Burchard.) 
Permanent Teeth (dentes permanentes) (Figs. 802, 803, 804, and 806). The 
Incisors (dentes incisivi).-The incisors or cutting teeth are so named from their 
presenting a sharp cutting edge, adapted for incising the food. They are eight in 
number, and comprise the four front teeth in each jaw. 
The crown is directed almost vertically and is spade-like in form; it has the form 
of a truncated cone whose top has been compressed into a sharp horizontal cutting THE TEETH 
1197 
edge. Before being subjected to attrition this edge presents three small elevations. 
The labial surface is convex, and marked by free longitudinal ridges extending 
from the edge tubercles toward the neck of the tooth. The lingual surface is con- 
cave, and is marked by two marginal ridges extending from an encircling ridge 
at the neck to the angles of the cutting edge of the tooth. The ridge at the neck 
is termed the cingulum or basal ridge. The mesial and distal surfaces are triangular, 
the apex of the triangle being at the cutting edge. The neck of the tooth is 
constricted. The root is long, single, and has the form of a transversely flattened 
cone, thicker before than behind. The root may be curved. 
The Incisors of the Upper Jaw are altogether larger and stronger than those of 
the lower jaw, the central incisors being larger and flatter than the lateral incisors. 
They are directed obliquely downward and forward. 
The Inciscrs of the Lower Jaw are smaller and flatter than the upper, and the 
elevations upon their lingual faces are not marked. The two central are smaller 
than the two lateral incisors, being the smallest of all the teeth. The roots of these 
teeth are flattened laterally. 
Fig. 803.-Right half of upper jaw (from below), 
with the corresponding teeth. The letters and numbers 
point to the classes of teeth and the numbers in 
classes. 
Fig. 804.-Right half of lower jaw, with the cor- 
responding teeth. The letter and numbers point to 
the various cusps or their modifications on the dif- 
ferent teeth. (Burchard.) 
The Canine Teeth or Cuspidati {dentes canini).-The canine teeth are four in 
number, two in the upper, two in the lower jaw-one being placed distal to each 
lateral incisor. They are larger and stronger than the incisors, especially in the 
roots, which are deeply implanted and each causes a well-marked prominence 
of the process at the place of insertion. 
The crown is large, of spear-head form, and its very convex labial surface is 
marked by three longitudinal ridges. The concave lingual surface is also marked 
by three ridges which unite at a basal ridge. The point or cusp is longer than in 
the other teeth, and is the point of division between a short mesial and a long 
distal cutting edge. These two edges form an obtuse angle with each other. 
The root is single, oval, or elliptical on transverse section, and is longer and more 
prominent than the roots of the incisors. 
The Upper Canines or cuspids, vulgarly called the eye teeth, are larger and longer 
than the two lowTer, and in occlusion are distal to them to the extent of half the 
width of the crown. 
The Lower Canines, vulgarly called the stomach teeth, have the general form of 
the upper cuspids, but their lingual surfaces are much more flattened, owing to 1198 
THE ORGANS OF DIGESTION 
the absence of the elevations marking the upper. Their roots are more flattened 
and may be bifid at their apices. 
The Bicuspid Teeth or the Premolars (dentes premolares).-The bicuspid teeth 
are eight in number, four in each jaw; they are placed distal to the cuspid teeth, 
two upon each side of the jaw. They are double cuspids in form. 
The crown is surmounted by two cusps, one buccal and one lingual, separated 
by a groove, the buccal being more prominent and larger than the lingual. The 
lower bicuspids are not truly bicuspid, the first having but a primitive lingual cusp, 
the second having the lingual cusp divided into two sections-i. e., it is usually 
tricuspid. The necks of the teeth are oval; the roots are single and laterally com- 
pressed, that of the first upper bicuspid being frequently bifid. The first upper 
bicuspid is usually the largest of the series. The roots of the lower bicuspids are 
less compressed and more rounded. 
The Molar Teeth, the Multicuspidati or Grinders (dentes molares).-The molar 
teeth are the largest and strongest teeth of the denture. They are adapted by 
their forms for the crushing and grinding of the food. They are twelve in number, 
six in each jaw, three being placed posterior to each second bicuspid. 
The crowns are cuboidal in form, are convex buccally and lingually; they are 
flattened mesially and distally. They are formed by the fusion of three primitive 
cuspids in the upper and four in the lower. To these are added in the first and 
second upper molars a disto-lingual tubercle, and in the first and third molars of 
the lower jaw a disto-buccal tubercle. The unions of the primitive forms are 
marked by sulci. The necks of these teeth are large and rhomboidal in form. 
The roots of the upper molars are three in number-one large lingual or palatal 
root, and two smaller buccal roots. In the lower molars, two roots are found, a 
mesial and a distal, each of which is much flattened from before backward. 
The First Molar Teeth are the largest of the dental series; they have four cusps 
on the upper and five in the lower-three buccal and two lingual. 
The Second Molars are smaller; the crowns of the upper are compressed until the 
disto-lingual cusp is reduced. The crowns of the lower are almost rectangular, 
with a cusp at each angle. 
The Third Molars are called the wisdom teeth or dentes sapientae (dentes serotini), 
from their late eruption; they have three cusps upon the upper and five upon the 
lower. The three roots of the upper are frequently fused together, forming a 
grooved cone, which is usually curved backward. The roots of the lower, two 
in number, are compressed together, and curve backward. 
Arrangement of the Teeth.1-The human teeth are arranged in two parabolic 
arches, the upper row or arch (arcus dentalis superior) being larger, its teeth over- 
lapping the lower row or arch (arcus dentalis inferior). The average distance 
between the centres of the condyles of the inferior maxillary bones is about four 
inches, which is also the distance from either of these points to the line of junction 
between the lower incisor teeth. Whether the jaw be large or small, the equilateral 
triangle indicated is included in it; the range of size is between three and one-half 
and four and one-half inches. 
Owing to the smaller sizes of the lower incisors, the teeth of the lower jaw are 
each one-half a tooth in advance of its upper fellow, so that each tooth of the dental 
series has two antagonists, with the exception of the lower central incisors and 
upper third molars (Figs. 805 and 806). 
The grinding faces of the upper bicuspidsand molars curve progressively upward 
and point outward, the first molar being at the lowest point of the curve, the third 
molar at the highest. The curve of the lower dental arch is the reverse, the first 
molar at its deepest part, the third molar at its extremity. The greater the depth 
' After Dr. W. G. A. Bonwill. THE TEETH 
1199 
to which the upper incisors overlap the lower, the more marked this curve and 
the more pointed are the cusps of the grinding teeth. 
Fig. 805.-View of teeth in situ, with the external plates of the alveolar processes removed. (Cryer.) 
Fig. 806.-Front and side views of the teeth and jaws. (Cryer.) 
The movement of the human mandible is forward and downward, the resultant 
of these directions being an oblique line, upon an average of 35 degrees from 
the horizontal plane.1 When the lower jaw is advanced until the cutting edges of 
' W. E. Walker, Dental Cosmos, 1896. 1200 
THE ORGANS OF DIGESTION 
the incisors are in contact, the jaws are separated, but at the highest point of the 
lower arch its third molar advances, and meets and rests upon a high point, the 
second molar of the upper arch, and thus undue strain upon the incisors is obviated. 
In the lateral movements of the mandible but one side is in effective action at 
one time; the oblique positions of the cusps of the opposite teeth are such that 
Pulp 
camty. 
Crown. 
1 
Neck. 
Root. 
2- 
Fig. 807.-Vertical section of a molar tooth. 
when either side is in action the other 
is balanced at two or more points. 
There is an anatomical correspond- 
ence between the forms and arrange- 
ment of the teeth, the form of the con- 
dyle of the mandible, and the muscular 
arrangement. Individuals who have 
teeth with long cusps have the head of 
the bone much rounded from before 
backward, and have a preponderance 
of the direct over the oblique muscles 
of mastication, and vice versa; teeth 
with short or no cusps are associated 
with a flattened condyle and strong 
oblique muscles. 
Very great aberrations in the dental 
arrangement are frequently followed by 
accommodative changes in the heads of 
the mandible. 
Structure of the Teeth. The Dental 
Pulp (pulpa dentis).- A longitudinal 
section of a tooth will show the pres- 
ence of a central chamber having the 
general form of the crown of the tooth. 
Processes of the chamber pass from its 
body, one for each root and down each 
root, and open at the apex by a minute 
orifice. This cavity is known as the pulp-chamber or pulp-cavity (cavum dentis) 
(Figs. 807 and 808). The minute canal in each root is called the pulp-canal or root- 
canal (canalis radicis dentis). The foramen at the apex of the root is the apical 
foramen (foramen apicis dentis). The cavity contains a soft, vascular, and sensitive 
organ called the dental pulp (pulpa dentis'). It is made up of fibrous cellular con- 
nective tissue, the fibres of which are extremely fine, and contains numerous blood- 
vessels and nerves, which enter by way of the apical foramina. It has not been 
proved that there are lymphatics in the dental pulp, although some authors assert 
that they exist (Wangermann and others). It seems to have been proved that the 
spaces between the fibres of the pulp communicate with the lymphatic system. The 
periphery of the pulp is bounded by a layer of cells arranged like columnar epithe- 
lium, each cell sending one or more branched processes through the basic substance 
4 
c 
a 
3- 
.5 
Fig. 808. - Vertical section of a tooth in situ (15 
diameters), c is placed in the pulp-cavity, opposite 
the cervix or neck of the tooth ; the part above is the 
crown, that below is the root (fang). 1. Enamel with 
radial and concentric markings. 2. Dentine with 
tubules and incremental lines. 3. Cement or crusta 
petrosa, with bone corpuscles. 4. Dental periosteum. 
5. Bone of lower jaw. THE TEETH 
1201 
of the dentine. These processes constitute the dentine fibres. Other processes come 
off from the cells which pass in the direction of the pulp and surround it. The 
cells at the periphery of the pulp are the 
dentine-forming cells, the odontoblasts of Wal- 
deyer. The blood-vessels break up into in- 
numerable capillary loops which lie beneath 
the layer of odontoblasts. The nerve-fibrils 
break up into numberless non-medullary fila- 
ments, which spread out beneath the odonto- 
blasts, and probably send terminal filaments 
to the extreme periphery of the pulp outside 
the odontoblasts. 
The matrix cells and their processes are 
irregularly arranged in the body of the pulp, 
but in the canal portion the fibrillae are in the 
direction of the axis of the root. 
The Solid Portion of the Tooth.-The sec- 
tion will exhibit three hard tissues in a tooth: 
one, the proper dental substance, forming the 
greater mass of the tooth; hence its name 
dentine or ivory. The dentine upon the ex- 
posed crown is sheathed by a layer called 
the enamel ; the dentine of the root is em 
closed in a distinct tissue, the cementum or 
crusta petrosa; both cementum and enamel are thinnest at the neck and thickest 
upon their distal portions. 
Fig. 809.--From a ground-section through 
the parts of a dentine, near the pulp, of a 
human canine tooth which has been impreg- 
nated with pigment. The dental canaliculi are 
cut across and are joined together by side 
branches. X 400. 
Fig 810.-Longitudinal ground-section through the apex of a canine tooth from a three-and-a-half-year-old 
boy. The entrance of the dental canaliculi between the enamel prisms and the course taken by the latter are 
Shown. X 135. (Szymonowicz.) THE ORGANS OF DIGESTION 
1202 
The Ivory or Dentine (substantiae ehurnea) (Figs. 808, 809,810, and 811) forms 
the principal mass of a tooth; in its central part is the cavity enclosing the pulp. It 
is a modification of osseous tissue, from which it differs, however, in the fact that 
it does not contain cells placed in cavities, but the cells lie in the periphery of the 
pulp, against but not in the dentine. The dentine contains the processes of the 
cells, which are known as dental or dentinal fibres. On microscopic examination 
it is seen to consist of a number of minute wavy and branching tubes having 
distinct parietes. They are called the dentinal tubuli or dental canals, and are 
embedded in a dense homogeneous substance, the intertubular tissue. 
The dentinal tubuli (canaliculi dentales) (Fig. 811) are placed parallel with one 
another, and open at their inner ends into the pulp-cavity. In their course to the 
periphery they present two or three curves, and are twisted on themselves in a spiral 
direction. The direction of these tubes varies; they are vertical in the upper por- 
tion of the crown, oblique in the 
neck and upper part of the root, 
and toward the lower part of the 
root they are inclined downward. 
The tubuli, at their commence- 
ment, are about of an inch in 
diameter; in their course they di- 
vide and subdivide dichotomously, 
so as to give to the cut surface of 
the dentine a striated appearance. 
From the sides of the tubes, espe- 
cially in the root, ramifications of 
extreme minuteness are given off, 
which join together in loops in the 
intertubular substance, or termin- 
ate in small dilatations, from which 
branches are given off. Near the 
pulp the lateral branches are few 
and are almost at right angles to 
the canals. Nearer the periphery 
the lateral branches are more nu- 
merous, and they come off at 
acute angles. The terminations of 
the chief canals at the periphery 
vary. In the crown they break up 
into branches like fingers just be- 
neath the enamel. Some of these 
finger-like branches leave the den- 
tine and enter the cement substance between enamel prisms. The majority of 
the chief canals end in blind extremities at the margin of the enamel and do not 
enter this structure. In the lower portion of the tooth the chief canals do not 
emerge from the dentine, but end at the margin of the cement in blind extremities. 
They may reach the spaces of the granular sheath. Near the periphery of the 
dentine of the crowm the finer ramifications of the tubuli pass through a layer of 
irregular branched spaces which communicate with each other. These are called 
the interglobular spaces of Czermak (spatia inter global aria) (Fig. 811, J). These 
spaces are gaps in the dentine due to failure of calcification and are filled with 
uncalcified dentine. The outer part of the dentine in the lower portion of the 
tooth contains a layer of interglobular spaces known as the granular layer or 
granular sheath of Tomes. The dentinal tubuli have comparatively thick walls, 
and contain slender cylindrical prolongations from the processes of the cells of 
Fig. 811.-Ground-section through the root of a human 
premolar. D, dentine ; A", cement corpuscles ; 0, osteoblasts ; 
Ep., remains of Hertwig's epithelial sheath, 200 diameters ; 
J, interglobular spaces. (Rose.) THE TEETH 
1203 
the pulp-tissue already mentioned, and first described by Mr. Tomes and named 
Tomes's fibres or dentinal fibres. These dentinal fibres are analogous to the soft 
contents of the canaliculi of bone. Between Tomes's fibres and the ivory around 
the canals there is a tissue which is markedly resistant to the action of acids-the 
dentinal sheath of Neumann. 
The intertubular substance or tissue is translucent and contains the chief part 
of the earthy matter of the dentine. After the earthy matter has been removed 
by steeping a tooth in weak acid the animal basis remaining may be torn into 
laminae which run parallel with the pulp-cavity across the direction of the tubules. 
These laminae show the method of growth to be by deposition of successive strata 
of dentine. Fibrils have been found in the matrix of the intertubular substance, 
and are probably continuous with the dentinal fibres of Tomes. In a dry tooth a 
section of dentine often displays a series of lines-the incremental lines of Salter- 
which are parallel with the laminae above mentioned. These lines are caused by 
two facts: (1) The imperfect calcification of the dentinal laminae immediately 
adjacent to the line. (2) The drying process, which reveals these defects in the 
calcification. These lines are wide or narrow according to the number of laminae 
involved, and along their course, in consequence of the imperfection in the calci- 
fying process, little irregular cavities are left, which are the interglobular spaces 
already referred to. They have received their name from the fact that they are 
surrounded by minute nodules or globules of dentine. Other curved lines may 
be seen parallel to the surface. These are the concentric lines of Schreger, and are 
due to the optical effect of simultaneous curvature of the dentinal tubules. 
A 
B 
Fig. 812.-Enamel prisms (350 diameters). A, fragments and single fibres of the enamel isolated by the action 
of hydrochloric acid. B, surface of a small fragment of enamel, showing the hexagonal ends of the fibres. 
Chemical Composition.-According to Berzelius and Bibra, dentine consists 
of twenty-eight parts of animal and seventy-two of earthy matter. The animal 
matter is resolvable by boiling into gelatin. The earthy matter consists of phos- 
phate and carbonate of calcium, with a trace of fluoride of calcium, phosphate of 
magnesia, and other salts. 
The Enamel (substantia adamantina) (Figs. 808, 810, and 812) is the hardest and 
most compact part of a tooth, and forms a thin crust over the exposed part of 
the crown as far as the commencement of the root. It is thickest on the grind- 
ing surface of the crown until worn away by attrition, and becomes thinner toward 
the neck. It consists of a congeries of minute hexagonal rods, columns, or prisms 
known as enamel fibres or enamel prisms (prismata adamantina) (Fig. 812). In 
general, they lie parallel with one another, resting by one extremity upon the 
dentine, which presents a number of minute depressions for their reception, and 1204 
THE ORGANS OF DIGESTION 
forming the free surface of the crown by the other extremity. There are occa- 
sional collections of prisms which run diagonally. The prisms are directed 
vertically on the summit of the crown, horizontally at the sides; they are about 
the 3-3-V0 an inch in diameter, and pursue a more or less wavy course. By 
reflected light radial striations are visible. These are Schreger's lines, and are 
due to the fact that the prisms take an undulatory course and those of two layers 
may have opposite directions. Another series of lines, having a brown appear- 
ance from pigmentation, and denominated the parallel striae or brown striae of 
Retzius or the colored lines, are seen on a section of the enamel. These lines 
are concentric and cross the enamel rods. They are caused by the mode of 
enamel deposition. Inasmuch as the enamel columns, when near the dentine, 
cross each other and only become parallel farther away, a series of radial mark- 
ings, light and dark alternately, is obtained (Fig. 808). The enamel prisms are 
themselves calcified and are fixed to each other by a very small amount of cement 
substance. Numerous minute interstices intervene between the enamel-fibres 
near their dentinal surface. It is noted that some of the dentinal canals at the 
crown penetrate a certain distance between the rods of the enamel (Fig. 810). No 
nutritive canals exist in the enamel, except the very few dentinal canals which at 
the crown penetrate a short distance, and these are found only in a small area. 
Chemical Composition.-According to Bibra, enamel consists of 96.5 per cent, 
of earthy matter and 3.5 per cent, of animal matter. 'The earthy matter consists 
of the phosphate and the carbonate of calcium, with traces of fluoride of calcium, 
phosphate of magnesia, and other salts. 
The enamel of a recently erupted tooth is covered by a membrane, the thick- 
ness of which is %$$$ of an inch. It is known as enamel cuticle or Nasmyth's mem- 
brane (cuticula dentis). It is probably the most recent, and hence an uncalcified, 
or partly calcified enamel layer. Some believe it to be a product of the outer layer 
of the cells of the enamel organ. 
The Cortical Substance, Cementum or Crusta Petrosa (substantia ossea) (Figs. 808 
and 811) is disposed as a thin layer on the roots and neck of a tooth, from the termi- 
nation of the enamel as far as the apex of the root, where it is usually very thick. At 
the neck it overlays a slight margin of enamel. In structure and chemical com- 
position it is true bone. It contains, sparingly, the lacunae and canaliculi which 
characterize true bone; the lacunae placed near the surface have the canaliculi radi- 
ating from the side of the lacunae toward the periodontal membrane or dental 
periosteum, and those more deeply placed join with adjacent dentinal tubuli. The 
teeth of the young usually contain Haversian systems in the thicker portions of 
the cementum. The neck of the tooth does not contain lacunae. The cementum 
is occasionally laminated. Sharpey's fibres (p. 37) are very numerous. Some of 
the lacunae of the cementum receive dentinal tubes from the dentine. 
As age advances the cement increases in thickness, and gives rise to those bony growths, or 
exostoses, so common in the teeth of the aged; the pulp-cavity becomes also partially filled up 
by a hard substance intermediate in structure between dentine and bone (the osteo-dentine of 
Owen; the secondary dentine of Tomes). It is formed by the odontoblasts, the dental pulp 
lessening in volume. 
Development of the Teeth (Figs. 813, 814, 815, and 816).-The teeth are an 
evolution from the dermoid system, and not of the bony skeleton; they are devel- 
oped from two of the blastodermic layers, the epiblast and mesoblast. From the 
former the enamel is developed; from the latter the dentinal pulp, dentine, cemen- 
tum, and pericementum. It is customary to view the development of the per- 
manent and temporary teeth as separate studies. 
The earliest evidence of tooth-formation in the human embryo is observed 
about the seventh week. The mucous membrane covering the embryonic jaws is 
seen to rise as a longitudinal ridge along the summit of each jaw. This ridge is THE TEETH 
1205 
the maxillary rampart of Kolliker and Waldeyer. A transverse section through the 
jaw will show the elevation to be due to a linear and outlined activity of the 
germinal epithelial layer; a corresponding epithelial growth is seen to sink as a 
band into the mesoblastic tissue beneath. This band is called the dental lamina 
or dental band. The local cell-activity continues, and in its descent the band 
appears to meet with a resistance which causes a flattening of its extremity into a 
continuous lamina. From the inner (toward the tongue) edge of the lamina 
epithelial cords are given off, ten in number, one for each temporary tooth. 
12 3 4 
Fig. 813.-Diagram of method of development of the teeth. 1. Early stage. 4. Later stage. 2, 3. Inter- 
mediate stages. «. Common dental germ. o. Special dental germ (milk), o'. Special dental germ (permanent). 
p. Papilla, e. Dental furrow. (Gegenbauer.) 
The growth of each cord continues, and each expands into a flask-like form, the 
walls covered by a layer of germinal cells, its interior by swollen mature cells. 
The ingrowing bulb is now seen to flatten upon its lower surface, as though it had 
met with an outlined resistance from the mesoblastic tissue beneath. The epithelial 
ingrowth assumes the general form of the several teeth; it is the enamel-organ of 
the tooth (Fig. 813). The cellular tissue of the jaw beneath the cap of the enamel- 
organ grows and projects into the cap. This projection is the dentine papilla 
(papilla dentis). At this period the mesoblastic tissue around each enamel-organ 
is seen to become differentiated into fibrous tissue surrounding the enamel-organs, 
Internal enamel layer 
' or adamantoblasts 
Dental furrow- 
Remains of ' ' neck ' ' of 
enamel organ, or of the' 
common dental germ 
Dental sac 
■Enamel pulp 
External enamel 
layer 
Permanent special 
dental germ 
Papilla 
Meckel's cartilage.- 
Lower jaw. 
Fig. 814.-Vertical section of the inferior maxilla of an early human foetus. (Magnified 25 diameters.) 
but at some distance from them. Islets of bone are also seen to be forming the 
beginning of the bony maxillae. 
The indentation of the base of the enamel-organ continues until it assumes 
the form of the future teeth. The cells bounding the organ assumes a cylindrical 
form; the cells of the interior become much expanded, and irregular in size and 
form. 
The mesoblastic tissue underlying the enamel-organ is much condensed; evi- 
dences of cellular differentiation and a vascular system appear. Bone continues to 1206 
THE ORGANS OE DIGESTION 
develop until all of the tooth-follicles are embraced in a gutter of bone. From the 
lingual side of the cords of the temporary teeth epithelial buds are given off, which 
sink into the mesoblastic tissue and form the enamel-organs of the permanent 
teeth. The condensation of fibrous tissue continues until each embryonic tooth is 
enveloped in a sac, the dental sac (Fig. 814); this, together with all of its contents, 
is called the dental follicle. 
The tooth which is undergoing development with its enamel-organ and dentine 
papilla is known as the tooth germ. This tooth germ is encompassed and shut off 
from surrounding structures by the bag of membranous structure known as the 
dental sac. 
The cells of the enamel-organ now undergo a series of differentiations: the 
inner layer, arranged as columnar epithelium, are the enamel cells, or ameloblasts. 
The layer is called the ameloblastic or enamel-forming layer (Figs. 814 and 815). 
The cells of the outer wall remain cuboidal; the cells which lie between become 
much distended, and on account of their appearance when seen in section this 
portion of the organ is called the enamel jelly or the stellate reticulum. The layer of 
cells immediately contiguous to the ameloblasts form a layer called the stratum 
intermedium (Fig. 815 A, D). 
Fig. 815.-A. Section through tooth-follicle-human canine seven and one-half months. A. Follicular wall. 
B. Outer epithelial coat. 0. Stellate reticulum. D. Stratum intermedium. E. Ameloblasts. F. Odonto- 
blasts. G. Pulp. 
B. Diagram after Williams (Dental Cosmos, 1896), mode of enamel deposition. A. Blood-supply to B, secret- 
ing papillae. C. Layer of ameloblasts containing enamel globules and droplets of calcoglobulin. D. Enamel- 
globules deposited. E. Formed dentine. F. Forming dentine. G. Layer of odontoblasts. H. Blood-supply 
to odontoblastic layer. 
The enclosed mesoblastic papilla (the future dental pulp} has its peripheral cells, 
which are called odontoblasts, differentiated into columnar bodies disposed as a 
layer, each cell having a large nucleus. The vascular supply of the pulp is now 
well marked. A section of a follicle at this period will exhibit the follicular wall 
springing from the base of the dental papilla and having a well-marked blood- 
supply. The bony alveolar walls are well outlined, and evidences of a periosteum 
appear (Figs. 814 and 815). 
Development of Enamel (Fig. 815 B).-In point of time, the deposition of den- 
tine actually begins before that of enamel, so that the first-formed layer of enamel 
is deposited against a layer of immature dentine. The enamel is built up of two 
distinct substances-globules of uniform size which are formed by the amelo- 
blasts, and a cementing substance, probably an albuminate of calcium (calco- 
globulin), the basis of all the calcified tissues. At the ends of the ameloblasts, 77/// TEETH 
1207 
next to the dentine, the secretion of calco-globuhn is deposited, and into the 
plastic mass the enamel-globules are extruded, each globule remaining con- 
nected with the ameloblasts by plasmic strings, which also join the globules 
laterally.1 
The first deposit of enamel begins in the tips of the cusps, and is quickly fol- 
lowed by a disappearance of the stellate reticulum at that point; the stellate retic- 
ulum appears to atrophy, so that the vascular follicular wall is brought into 
direct apposition with the stratum intermedium, which becomes differentiated into 
a glandular (secreting) tissue which elaborates the calcic albuminous basis of the 
enamel. The secretion passes from the cells of the stratum intermedium through a 
membrane into the ameloblasts, where it is in part combined with the cellular 
globules, and irregular masses of it are extruded as cementing substance. The 
deposition continues until the enamel-cap has its typical form. The deposition 
of the layers of globules is indicated by parallel lines transverse to the axes of the 
enamel-rods. At the completion of amelification the ameloblasts are partially 
calcified and form the enamel cuticle or Nasmyth's membrane (cuticula dentis). 
Formation of Dentine.-The layer of columnar cells bounding the periphery of 
the pulp, the odontoblasts, are in apposition with a plexus of capillary vessels 
(Fig. 816). Each cell is a secreting body which selects the material for dentine- 
building. Against the layer of ameloblasts 
covering the dental papilla the odontoblasts 
deposit globules, of the calcium albuminate., 
and receding as the deposits are made, leave 
one or more protoplasmic processes in the 
calcic deposit. These are known as Tomes's 
fibres. The process continues until the normal 
dentine thickness is formed. The deposit is 
laid down in a scaffolding of finely fibrillated 
tissue. The layer of formative cells remains 
constant. The remains of the dentine papilla 
constitute the pulp and lie in the pulp-cavity 
(p. 1200). 
Formation of Cementum. - Hertwig asserts 
that the epithelial edge of the enamel organ 
formed by the inner and outer epithelial layers 
of the organ grows downward, or rather the developing tooth grows upward until 
the future root-form of the tooth is outlined by a double layer of epithelial cells, 
constituting the root-sheath of Hertwig. The growth of the alveolar process is 
synchronous. 
Upon the pulp side of the sheath a layer of odontoblasts is developed; upon 
the outer side the fibrous encasement becomes closely attached to the sheath and a 
layer of osteogenetic cells is differentiated. These cells are called cementoblasts. 
The growth of the dentine of the root is exactly similar to the growth of that of 
the crown. The epithelial sheath undergoes atrophic changes, leaving the epithe- 
lial whorls which remain in the pericementum. The cementum is developed as 
subperiosteal bone. The cementum over the apex of the root is not formed until 
after the eruption of the tooth. 
Formation of Alveoli.-By the time the crowns of the teeth have formed, each 
is enclosed in a loculus of bone which has developed around it and at some distance 
from it; the loculus is open at the top toward the gums, where it is closed by 
fibrous tissue; the developing permanent tooth is contained in the same loculus, 
but is later separated from the temporary tooth by a growth of bone. The alveolar 
Fig. 816.-Part of section of developing 
tooth of young rat, showing the mode of 
deposition of the dentine (highly magnified). 
a. Outer layer of fully-calcified dentine. 
b. Uncalcified matrix with a few nodules of 
calcareous matter. c. Odontoblasts with 
processes extending into the dentine, d. Pulp. 
The section is stained with carmine, which 
colors the uncalcified matrix, but not the cal- 
cified part. 
' J. L. Williams, Dental Cosmos, 1896. 1208 
THE ORGANS OF DIGESTION 
process is not completed until after the eruption of the teeth. During eruption 
that portion of the process overlying the crown undergoes absorption, and as soon 
as the immature tooth has erupted the alveolar process is developed about the root, 
whose formation is also completed after eruption. 
Development of the Permanent Teeth.-The permanent teeth as regards their 
development may be divided into two sets: (1) those which replace the temporary 
teeth, and which, like them, are ten in number; these are the successional perma- 
nent teeth; and (2) those which have no temporary predecessors, but are super- 
added at the back of the dental series. These are three in number on either side 
in each jaw, and are termed the superadded permanent teeth. They are the three 
molars of the permanent set, the molars of the temporary set being replaced by 
the premolars or bicuspids of the permanent set. 
The Development of the Successional Permanent Teeth-the ten anterior ones 
in either jaw-will be first considered. As already stated, the germ of each 
milk tooth is a special thickening of the "free" edge of the common dental germ 
or dental lamina. In like manner is formed the special dental germ of each of 
the successional permanent teeth. But these thickenings are not at the "free" 
edge of the dental lamina, but occur behind and lateral to each of the milk-tooth 
germs (Fig. 813). There are ten of these, and they appear in order, about the 
sixteenth week, on each side, the central incisor germs being the first. 
These special dental germs now go through the same transformations as 
were described in connection with those of the milk teeth, and the changes also 
eventuate in the germs becoming enamel organs; that is, they recede into the 
substance of the gum behind the germs of the temporary teeth. As they recede 
they become flask-shaped, form an expansion of their distal extremity, and finally 
meet a papilla, which has been formed in the mesoblast, just in the same 
manner as was the case in the temporary teeth. The apex of the papilla inden- 
tates the dental germ, which encloses it, and forming a cap for it, undergoes 
analogous changes to those described in the development of the milk teeth, and 
becomes converted into the enamel, whilst the papilla forms the dentine of the 
permanent tooth. In its development it becomes enclosed in a dentinal sac which 
adheres to the hack of the sac of the temporary tooth. The sac of each perma- 
nent tooth is also connected with the fibrous tissue of the gum by a slender band 
of the gubernaculum, which passes to the margin of the jaw behind the correspond- 
ing milk tooth (see above). 
The Superadded Permanent Teeth-three on each side in each jaw-arise from 
successive extensions backward-i. e., along the line of the jaw-of the common 
dental germ from the back part of the special dental germ of the immediately 
preceding tooth. During the fourth month or seventeenth week, in that portion 
of the common dental germ which lies behind-i. e., lateral to the special dental 
germ of the last temporary molar tooth, and which has hitherto remained unal- 
tered-there is developed the special dental germ of the first permanent molar 
into which a papilla projects. In a similar manner, about the fourth month after 
birth the second molar is formed, and about the third year the third molar. 
Eruption.-When the calcification of the different tissues of the milk tooth 
is sufficiently advanced to enable it to bear the pressure to which it will be after- 
ward subjected, its eruption takes place, the tooth making its way through the 
gum. The gum is absorbed by the pressure of the crown of the tooth against it, 
which is itself pressed up by the increasing size of the fang. At the same time 
the septa between the dentinal sacs, at first fibrous in structure, ossify and thus 
form the loculi or alveoli; these firmly embrace the necks of the teeth and afford 
them a solid basis. 
Previous to the permanent teeth penetrating the gum, the bony partitions 
which separate their sacs from the deciduous teeth are absorbed, the roots of THE TEETH 
1209 
the temporary teeth disappear by absorption through the agency of particular 
multinucleated cells, called odontoclasts, which are developed at the time in the 
neighborhood of the root, and the permanent teeth become placed under the 
loose crown of the deciduous teeth; the latter finally become detached, and the 
permanent teeth take their place in the mouth (Fig. 817). 
Fig. 817.-The milk-teeth in a child of about four years. The permanent teeth are seen in their alveoli. (Cryer.) 
Calcification of the permanent teeth proceeds in the following order: First 
molar, soon after birth; the central incisor, lateral incisor, and cuspid, about six 
months after birth; the bicuspids, at the second year or later; second molar, end 
of second year; third molar, about the twelfth year. 
The Eruption of the Temporary Teeth commences at the seventh month, and is 
complete about the end of the second year. 
The periods for the eruption of the temporary set are (C. S. Tomes)- 
Lower central incisors . . . . . 6 to 9 months. 
Upper incisors . . . . . . . 8 to 10 ' 
Lower lateral incisors and first molars . . 15 to 21 " 
Canines . . . . . . . . 16 to 20 " 
Second molars . . . . . . 20 to 24 " 
The Eruption of the Permanent Teeth takes place at the following periods, the 
teeth of the lower jaw preceding those of the upper by a short interval: 
61 years, first molars. 10th year, second biscuspid. 
7th year, two middle incisors. 11th to 12th year, canine, 
Sth year, two lateral incisors. 12th to 13th year, second molars. 
9th year, first bicuspid. 17th to 21st year, third molars. 1210 
THE OHG A NS OF DIGESTION 
The Palate (Palatum). 
The palate forms the roof of the mouth; it consists of two portions, the hard 
palate in front, the soft palate behind. 
The Hard Palate (palatum durum) (Figs. 818 and 819).-The hard palate is 
bounded in front and at the sides by the upper alveolar arches and gums. In 
front and to the sides it is continuous with the gums; behind, it is continuous 
with the soft palate. It is formed by the palate processes of the superior maxil- 
lary bones and the palate processes of the palate bones (Fig. 72). It is covered by a 
dense structure formed by the periosteum and mucous membrane of the mouth, 
which are intimately adherent, particularly to the front and sides, by means of 
RAPHE 
ANTERIOR 
* PILLAR 
POSTERIOR 
PILLAR 
EPIGLOTTIS 
Fig. 818.-Antero-inferior surface of the soft palate. The tongue has been removed, so that the pharyngeal 
isthmus is distinctly seen. (Luschka.) 
a layer of fibrous tissue. Along the middle line is a linear ridge or raphe {raphe 
palati), which terminates anteriorly in a small papilla, the incisive papilla (papilla 
incisiva), corresponding with the inferior opening of the anterior palatine fossa. 
This papilla receives filaments from the naso-palatine and anterior palatine 
nerves. The incisive papilla in a recently born child is continuous with the 
gum and the frenulum of the upper lip. On either side and in front of the raphe 
the mucous membrane is thick, pale in color, and corrugated; these corruga- 
tions, which are composed of fibrous tissue, are the palatine rugae (plicae pala- 
tinae transversae). In very young children the rugae are distinct and definite. 
In the aged they are indistinct. Behind, it is thin, smooth, and of a deeper 
color; it is covered with squamous epithelium, and the fibrous tissue beneath it THE PALATE 
1211 
contains many mucous glands, the palatine glands (glandulae palatinae). The 
palatine vessels and nerves lie in the fibrous tissue beneath the mucous membrane. 
The Soft Palate or Velum Pendulum Palati (palatum molle) (Figs. 818, 819, 
and 824).-The soft palate is a movable fold suspended from the posterior border 
of the hard palate, and forming an incomplete septum between the mouth and 
pharynx. It consists of a fold of mucous membrane enclosing muscular fibres, 
an aponeurosis, vessels, nerves, adenoid tissue, and mucous glands. When 
occupying its usual position it is relaxed and pendent and its oral surface is 
concave, continuous with the roof of the mouth, and marked by a median ridge 
or raphe, which indicates its original separation into two lateral halves. Its 
pharyngeal surface is convex, and continuous with the mucous membrane cover- 
ANTERIOR 
PALATINE CANAL 
-RAPHE 
PALATINE 
GLANDS 
DESCENDING 
PALATI N E - 
ARTERY 
Fig. 819.- The palatine vault on the right side of the mucous membrane has been removed. The left side shows 
the mucous membrane and the glandular layer. (Poirier and Charpy ) 
ing the floor of the posterior nares. Its anterior or upper border is attached to 
the posterior margin of the hard palate, and its sides are blended with the 
pharynx. Its posterior or lower border is free. The posterior portion of the 
soft palate is known as the vail of the palate (velum palatinum) and terminates 
posteriorly and externally on each side in a free margin, the posterior arch of 
the palate. 
Hanging from the middle of its lower border is a small, conical-shaped, pen- 
dulous process, the uvula (uvula palatina). The uvula varies greatly in length in 
different individuals. It is composed of glands and connective tissue, contains a 
prolongation of the Azygos uvulae muscle and is covered with mucous membrane, 
and arching outward and downward from the base of the uvula on each side are 
two curved folds of mucous membrane, containing muscular fibres, called the 
arches or pillars of the soft palate or pillars of the fauces (arcus palatini). 1212 
THE ORGANS OF DIGESTION 
The Anterior Pillar (arcus glossopalatinus) (Figs. 818 and 824). -The anterior 
pillar on eaeh side runs downward, outward, and forward to the side of the base 
of the tongue. These pillars are formed by the projection of the Palato-glossi 
muscles, covered by mucous membrane. 
The Posterior Pillar (arcus pharyngopalatinus) (Figs. 818 and 824).-The pos- 
terior pillar on each side is nearer to its opposite arch than is the anterior pillar to its 
opposite. These pillars are larger than the anterior; they run downward, outward, 
and backward to the sides of the pharynx, and are formed by the projection of the 
Palato-pharyngei muscles, covered by mucous membrane. The anterior and pos- 
terior pillars are separated below by a triangular interval in which the tonsil is lodged. 
The space left between the arches of the palate on the two sides is called the 
isthmus of the fauces (isthmus Jaucium). It is bounded, above, by the free margin 
of the soft palate; below, by the back of the tongue; and on each side by the 
pillars of the fauces and the tonsils. Through this isthmus the mouth com- 
municates with the pharynx. 
The Mucous Membrane of the Soft Palate.-The mucous membrane of the soft 
palate is thin, and covered with squamous epithelium on both surfaces, excepting 
near the orifice of the Eustachian tube, where its epithelium is columnar and 
ciliated.1 Beneath the mucous membrane on the oral surface of the soft palate 
is a considerable amount of adenoid tissue. The palatine glands form a con- 
tinuous layer on the pharyngeal surface and around the uvula. 
The Aponeurosis of the Soft Palate.-The aponeurosis of the soft palate is a thin 
but firm fibrous layer attached above to the posterior border of the hard palate, 
and becoming thinner toward the free margin of the velum. Laterally, it is con- 
tinuous with the pharyngeal aponeurosis. It forms the framework of the soft 
palate, and is joined by the tendons of the Tensor palati muscles. 
The Muscles of the Soft Palate.-The muscles of the soft palate are six on each 
side: the Levator palati, Tensor palati, Azygos uvulae, Palato-glossus, Palato- 
pharyngeus and Salpingo-pharyngeus (see pp. 403, 404, 405, and 406). The follow- 
ing is the relative position of these structures in a dissection of the soft palate 
from the posterior or naso-pharyngeal to the anterior or oral surface: Imme- 
diately beneath the pharyngeal mucous membrane is a thin stratum of mus- 
cular fibres, the posterior fasciculus of the Palato-pharyngeus muscle, joining 
with its fellow of the opposite side in the middle line. This posterior fasciculus 
is joined by the Salpingo-pharyngeus muscle. Beneath this are the Azygos uvulae 
and Salpingo-pharyngeus muscles, consisting of two rounded fleshy fasciculi, 
placed side by side in the median line of the soft palate. Next comes the aponeu- 
rosis of the Levator palati, joining with the muscle of the opposite side in the mid- 
dle line. Fourthly, the anterior fasciculus of the Palato-pharyngeus, thicker than 
the posterior, and separating the Levator palati from the next muscle, the Tensor 
palati. This muscle terminates in a tendon which, after winding around the hamu- 
lar process of the internal pterygoid plate of the sphenoid bone, expands into a 
broad aponeurosis in the soft palate, anterior to the other muscles, which have 
been enumerated. Finally, we have a thin muscular stratum, the Palato-glossus 
muscle, placed in front of the aponeurosis of the Tensor palati, and separated from 
the oral mucous membrane by adenoid tissue. 
The Blood-vessels of the Palate (Fig. 819).-The palate is supplied with blood by 
branches of the posterior or descending palatine branch of the internal maxillary artery 
(a. palatina descendens) and of the ascending or anterior palatine branch of the facial 
artery (a. palatina ascendens). The posterior palatine artery divides into the great 
and small palatine arteries (aa. palatinae major et minor), which run through the 
' According to Klein, the mucous membrane on the nasal surface of the soft palate in the foetus is covered 
throughout by columnar ciliated epithelium, which subsequently becomes squamous ; and some anatomists 
state that it is covered with columnar ciliated epithelium, except at its free margin, throughout life.-Ed. of 
15th English edition. THE TONSIL 
1213 
palatine canals and after emerging give off branches. Branches from the small 
palatine go to the soft palate, the large branch passes forward on the hard palate 
near the alveolar margin. The ascending palatine branch of the facial lies upon 
the medial surface of the Tensor palati muscle and is distributed to the soft palate 
and pharynx. A palatine vein corresponding to the descending palatine artery 
opens into the anterior facial vein. The pharyngeal veins also receive palatine veins. 
The Nerves of the Palate.-The large posterior palatine nerve emerges from the 
posterior palatine canal and accompanies the posterior palatine artery. The naso- 
palatine nerve emerges from the foramen of Scarpa and is distributed to the anterior 
portion of the hard palate. The soft palate is supplied by the small posterior 
palatine and the accessory palatine nerves. 
The Tonsil or Amygdala (tonsilla palatina) (Figs. 818 and 824).-The tonsils 
or amygdalae are two prominent bodies situated one on each side of the fauces, 
between the anterior and posterior pillars of the soft palate. They are of a 
rounded form, and vary considerably in size in different individuals. A recess, 
the supra-tonsillar fossa (fossa supratonsill ar is), may be seen, directed upward 
and backward above the tonsil. His regards this as the remains of the lower part 
of the second visceral cleft. The recess is covered by a fold of mucous mem- 
brane termed the plica triangularis. Externally the tonsil is covered with a fibrous 
capsule which joins the aponeurosis of the pharynx. The outer surface of the 
capsule is in relation with the inner surface of the Superior constrictor muscle 
of the pharynx, to the outer side of which is the Internal pterygoid muscle. The 
ascending palatine artery is close to the outer surface of the tonsil, the Superior 
constrictor muscle of the pharynx and the tonsillar capsule intervening. The 
tonsillar artery, which is sometimes a branch of the ascending palatine, is also 
close to the outer surface of the tonsil. The internal carotid artery lies behind 
and to the outer side of the tonsil, and nearly an inch (20 to 25 mm.) distant from 
it. It corresponds to the angle of the lower jaw. The surface of the tonsil 
which looks toward the pharynx presents from twelve to fifteen orifices, each 
leading into a small recess or crypt (fossula tonsillaris). From the crypts 
numerous follicles branch out into the substance of the tonsil by means of very 
irregular channels. The crypts are lined with stratified pavement epithelium. 
The epithelium of the crypts exhibits marked degenerative changes. The 
degeneration causes the formation of numerous communicating spaces, which 
contain leukocytes and lymphocytes. The crypts are surrounded with lymphoid 
tissue. In this are numerous lymphoid follicles (noduli lymphatici), which are 
placed in the submucous tissue. These follicles are analogous to those of 
Peyer's glands and consist of adenoid tissue. No openings from the capsules 
into the follicles can be recognized. They contain a thick grayish secretion. 
The Blood-vessels of the Tonsil.-The arteries supplying the tonsils are the 
dorsalis linguae from the lingual, the ascending palatine and tonsillar from the 
facial, the ascending pharyngeal from the external carotid, the descending palatine 
branch of the internal maxillary, and a twig from the small meningeal. The veins 
terminate in the tonsillar plexus, on the outer side of the tonsil, and the tonsillar 
plexus joins the pharyngeal plexus, which communicates with the pterygoid plexus 
of the internal jugular or facial vein. 
Lymphatics of the Tonsil.-Surrounding each follicle is a close plexus of lym- 
phatic vessels. From these plexuses the lymphatic vessels pass to the submaxillary 
lymph glands below the angle of the jaw. From the submaxilliary glands lymph 
passes to the deep cervical glands. 
The Nerves of the Tonsil.-A branch from the glosso-pharyngeal nerve by uniting 
with branches of the pharyngeal plexus forms the tonsillar plexus. The pharyn- 
geal plexus is formed by the pharyngeal branches of the glosso-pharyngeal and 
superior cervical ganglions and the pharyngeal branch of the vagus. 1214 
TILE ORGANS OF DIGESTION 
The Salivary Glands (Fig. 820). 
Numerous glands exist in the lips, cheeks, palate, and tongue, but by the term 
salivary glands are usually understood the three chief glandular masses on each 
side of the face. These are the principal salivary glands. They communicate 
with the mouth, pour their secretion into its cavity, and are named respectively 
the parotid, submaxillary, and sublingual. 
The Parotid Gland (glandulae parotid) (Fig. 646).-The parotid gland, so 
called from being placed near the ear (napd, near; ouq, (oto<;, the ear), is the 
largest of the three salivary glands, varying in weight from half an ounce to an 
ounce. It lies upon the side of the face immediately below and in front of the 
external ear. It is limited above by the zygoma; below, by the angle of the jaw 
and by a line drawn between the angle and the mastoid process: anteriorly, it 
Fig. 820.-The salivary glands. 
extends to a variable extent over the Masseter muscle; posteriorly, it is bounded 
by the external meatus, the mastoid process, and the Sterno-mastoid and Digastric 
muscles, slightly overlapping the two muscles. 
Its anterior surface is grooved to embrace the posterior margin of the ramus of 
the lower jaw, and advances forward beneath the ramus, between the two Ptery- 
goid muscles and superficial to the ramus over the Masseter muscle. Its outer 
surface is triangular and convex, slightly lobulated, is covered by the integument 
and parotid fascia, and has one or two lymphatic glands resting on it. Its inner 
surface (processus retromandibularis) extends deeply into the neck by means of 
two large processes, one of which dips behind the styloid process and projects 
beneath the mastoid process and the Sterno-mastoid muscle; the other is situated 
in front of the styloid process, and passes into the back part of the glenoid 
fossa, behind the articulation of the lower jaw. The structures passing through 
the parotid gland are-the external carotid artery, giving off its three terminal THE SALIVARY GLANDS 
1215 
branches: the posterior auricular artery emerges from the gland behind; the super- 
ficial temporal artery above; the transverse facial, a branch of the temporal, in front; 
and the internal maxillary winds through it as it passes inward, behind the neck 
of the jaw. Superficial to the external carotid is the trunk formed by the union 
of the temporal and internal maxillary veins; a branch, connecting this trunk 
with the internal jugular, also passes through the gland. The gland is also 
traversed by the facial nerve and its branches, which emerge at its anterior 
border; branches of the great auricular nerve pierce the gland to join the facial, 
and the auriculo-temporal branch of the inferior maxillary nerve emerges from the 
upper part of the gland. The internal carotid artery and internal jugular vein lie 
close to its deep surface. The triangular space occupied by the greater part of 
the gland is bounded in front by the posterior margin of the ramus of the jaw 
and the internal pterygoid muscle, and behind by the anterior edge of the Sterno- 
cleido-mastoid muscle, the tympanic portion of the temporal bone and the car- 
tilaginous portion of the external auditory meatus. Its floor is formed by the 
anterior and posterior walls of the space which meet about the styloid process. 
These walls are composed of fascia derived from the deep cervical fascia. The 
remaining side of the space is external and is formed by fascia, derived from the 
deep cervical fascia and called the parotid fascia. This space is called the parotid 
recess. Sir Frederick Treves1 denies that the fascial covering of the space is 
complete. He says it is deficient above between the anterior edge of the styloid 
process and the posterior border of the external pterygoid muscle. A portion 
of the gland does not occupy the space, but projects forward over the Masseter 
muscle. This projecting portion is the facial process. 
Lymph-glands, known as the parotid lymph-glands, are in and about the parotid 
gland, some being embedded in the outer surface of the parotid fascia, others 
being in the inner surface of the fascia, others in the gland itself, particularly 
along the temporo-maxillary vein and external carotid artery. They receive 
lymph from the anterior and lateral portions of the scalp, both eyelids, a portion 
of the cheek, the root of the nose, the outer portion of the external ear, the soft 
palate, the posterior nares, and the external auditory meatus. The vessels from 
them empty into the superficial cervical glands and the superior deep cervical 
glands. Between the parotid gland and the pharynx are the subparotid glands. 
They receive lymph from the nasal fossae, naso-pharynx and Eustachian tube, and 
vessels from the glands take lymph to the deep cervical glands.2 
The Duct of the Parotid Gland, called the Parotid Duct or Stenson's Duct (ductus 
parotideus [Stenmus]) (Fig. 820).-The duct of the parotid gland is about two 
inches and a half in length. It commences by numerous branches from the ante- 
rior part of the gland, crosses the Masseter muscle, and at its anterior border dips 
down into the substance of the Buccinator muscle, which it pierces; it then runs 
for a short distance obliquely forward between the Buccinator muscle and the 
mucous membrane of the mouth, and opens upon the inner surface of the cheek 
by a small orifice opposite the second molar tooth of the upper jaw (Fig. 824). 
Upon the beginning of Stenson's duct there is often an accessory parotid gland 
(glandulae parotis accessorial, which is often called the socia parotidis. It is a 
portion of the facial process. It is a detached portion of gland, and has a duct 
which opens into Stenson's duct. This accessory gland occasionally exists as a 
separate lobe, just beneath the zygomatic arch. In this position it has the trans- 
verse facial artery above it and some branches of the facial nerve below it. 
Surface Form.-The direction of the duct corresponds to a line drawn across the face about 
a finger's breadth below the zygoma; that is, from the lower margin of the concha to midway 
between the free margin of the upper lip and the ala of the nose. 
1 Applied Anatomy. 2 Poirier and Cun6o, Human Anatomy. 1216 
THE ORGANS OF DIGESTION 
Structure of the Parotid Duct.-The parotid duct is dense, it is of considerable 
thickness, and its canal is about the size of a crowquill; but at its orifice on the 
inner aspect of the cheek its lumen is greatly reduced in size. The duct consists 
of an external or fibrous coat, of considerable density, containing contractile 
fibres, and of an internal or mucous coat lined with short columnar epithelium. 
Vessels and Nerves.-The arteries supplying the parotid gland are derived from 
the external carotid, and from the branches given off by that vessel in or near its 
substance. The veins empty themselves into the external jugular through some 
of its tributaries. The lymphatics terminate in the superficial cervical and the 
deep cervical glands, passing in their course through several lymphatic glands 
placed on the surface and in the substance of the parotid. The nerves are 
derived from the plexus of the sympathetic on the external carotid artery, the 
facial, the auriculo-temporal, and great auricular nerves. It is probable that the 
branch from the auriculo-temporal nerve is derived from the glosso-pharyngeal 
through the otic ganglion. At all events, in some of the lower animals this has 
been proved experimentally to be the case. 
The Parotid Capsule.-The parotid gland is enclosed by two layers of the parotid 
fascia (fascia parotideomasseterica), which almost completely encompass the 
gland, 'rhe sheath is incomplete at one area toward the pharyngeal wall (see 
p. 1215). 
The parotid fascia comes from the deep cervical fascia. The external layer 
covers the gland. The internal layer lines the parotid recess. The external layer 
is the structure usually spoken of as the parotid fascia. Anteriorly it joins 
the fascia of the masseter; below it is continuous with the deep cervical fascia; 
above it is attached to the zygoma; behind it is adherent to the external auditory 
meatus and sheath of the Sternomastoid. The deep layer is adherent above to the 
external auditory meatus and back of the glenoid fossa; internally to the styloid 
process; below it is continuous with the deep cervical fascia. The stylomaxillary 
or stylomandibular ligament comes off from the parotid fascia. 
The Submaxillary Gland (glandida submaxillaris) (Fig. 820).-The submax- 
illary gland is situated below the jaw, in the anterior part of the submaxillary 
triangle of the neck. It is irregular in form and weighs about two drachms 
(8 to 10 grammes). It is covered by the integument, Platysma, deep cervical 
fascia, and the body of the lower jaw, corresponding to a depression on the 
inner surface of the body of the mandible, and lies upon the Mylo-hyoid, Hyo- 
glossus, and Stylo-glossus muscles, a portion of the gland passing beneath the 
posterior border of the Mylo-hyoid. In front of it is the anterior belly of the 
Digastric muscle; behind, it is separated from the parotid gland by the stylo- 
maxillary ligament, and from the sublingual gland in front by the Mylo-hyoid 
muscle. 'Che facial artery lies embedded in a groove in its posterior and upper 
border. A process is given off from the deep surface of the anterior portion of 
the gland. This is the deep process (Cunningham), and it passes with the duct 
beneath the Mylo-hyoid muscle. 
The Duct of the Submaxillary Gland or Wharton's Duct (ductus submaxillaris 
\Whartoni\).-The duct of the submaxillary gland is about two inches in length, 
and its walls are much thinner than those of the parotid duct. It commences by 
numerous branches from the deep portion of the gland which lies on the upper 
surface of the Mvlo-hyoid muscle, and passes forward and inward between the 
Mylo-hyoid and the Hyo-glossus and Genio-hyo-glossus muscles, then between the 
sublingual gland and the Genio-hyo-glossus muscle, and opens by a narrow orifice 
on the summit of a small papilla (caruncula sublingualis) at the side of the fraenum 
linguae. On the Hyo-glossus muscle it lies between the lingual and hypoglossal 
nerves, but at the anterior border of the muscle it crosses under the lingual nerve, 
and is then placed above it. THE SALIVARY GLANDS 
1217 
Vessels and Nerves.-The arteries supplying the submaxillary gland are branches 
of the facial and lingual. Its veins follow the course of the arteries. The lymph- 
atics drain into the submaxillary lymph-glands. There are no lymphatic glands 
in this salivary gland. The nerves are derived from the submaxillary ganglion, 
through which it receives filaments from the chorda tympani of the facial and 
from the lingual branch of the inferior maxillary, sometimes from the mylo-hyoid 
branch of the inferior dental, and from the sympathetic. 
The Sublingual Gland (glandula sublingualis) (Fig. 820).-The sublingual 
gland is the smallest of the salivary glands. It is situated beneath the mucous 
membrane of the floor of the mouth, at the side of the fraenum linguae, in contact 
with the inner surface of the lower jaw, close to the symphysis. It is narrow, 
flattened, in shape somewhat like an almond, and weighs about a drachm. It 
is in relation, above, with the mucous membrane; below, with the Mylo-hyoid 
muscle; in front, with the depression on the side of the symphysis of the lower 
jaw, and with its fellow of the opposite side; behind, with the deep part of the 
submaxillary gland; and internally, with the Genio-hyo-glossus, from which it 
is separated by the lingual nerve and Wharton's duct. Its excretory ducts or 
ducts of Rivinus (ductus sublingualis minores) are from eight to twenty in number. 
Alveolus. 
Crescent of Gianuzzi. 
Salivary duct. 
Fig. 821.-A highly magnified section of the submaxillary gland of the dog, stained with carmine. (Kiilliker.) 
They open separately into the mouth back of Wharton's duct and upon a fold 
of mucous membrane known as the plica sublingualis. The plica sublingualis is 
an elevated crest of mucous membrane caused by the projection of the gland on 
either side of the fraenum linguae. One or more ducts sometimes join to form 
a tube which opens into the Whartonian duct or remains independent, opening 
close to Wharton's duct on the sublingual papilla. This single duct is called 
the duct of Bartholin (ductus sublingualis major). 
Vessels and Nerves.-The sublingual gland is supplied with blood from the 
sublingual and submental arteries. Its nerves are derived from the lingual. 
Structure of Salivary Glands (Fig. 821).--The salivary glands are compound 
racemose glands, consisting of numerous lobes, which are made up of smaller 
lobules connected together by dense areolar tissue, vessels, and ducts. Each 
lobule consists of the ramifications of a single duct, dividing frequently like the 
branches of a tree, the branches terminating in dilated ends or alveoli, on which 
the capillaries are distributed. These alveoli, however, as Pfliiger points out, 
are not necessarily spherical, though sometimes they assume that form; some- 
times they are perfectly cylindrical, and very often they are mutually com- 
pressed. The alveoli are enclosed by a basement membrane which is continuous 
with the membrana propria of the duct. It presents a peculiar reticulated THE ORGANS OF DIGESTION 
1218 
structure, having the appearance of a basket with open meshes, and consisting 
of a network of branched and flattened nucleated cells. 
The alveoli of the salivary glands are of two kinds, which differ both in the 
appearance of their secreting cells, in their size, and in the nature of their secre- 
tion. The one variety secretes a ropy fluid which contains mucin, and such 
alveoli have therefore been named the mucous alveoli, whilst the other secretes a 
thinner and more watery fluid, which contains serum-albumin, and alveoli of 
this variety have been named serous or albuminous alveoli. The sublingual gland 
may be regarded as an example of the former variety, the parotid of the latter, 
rhe submaxillary is of the mixed variety, containing both mucous and serous 
alveoli, the latter, however, preponderating. 
Both varieties of alveoli are lined by cells, and it is by the character of these 
cells that the nature of the gland is chiefly to be determined. In addition, how- 
ever, the alveoli of the serous glands are smaller than those of the mucous ones. 
The Mucous Alveoli.-The cells in the mucous alveoli are spheroidal in shape, 
glassy, transparent, and dimly striated in appearance. The nucleus is usually 
situated in the part of the cell which is next the basement membrane, against 
which it is sometimes flattened. The most remarkable peculiarity presented by 
these cells is, that they give off an extremely fine process which is curved in a 
direction parallel to the surface of the alveolus, lies in contact with the membrana 
propria, and overlaps the process of neighboring cells. The cells contain a quan- 
tity of mucin, to which their clear, transparent appearance is due. 
Here and there in the alveoli are seen peculiar half-moon-shaped bodies lying 
between the cells and the membrana propria of the alveolus. They are termed 
the crescents of Gianuzzi or the demilunes of Heidenhain (Fig. 821), and are com- 
posed of polyhedral granular cells, which Heidenhain regards as young epithelial 
cells destined to supply the place of those salivary cells which have undergone 
disintegration. This view, however, is not accepted by Klein. 
Serous Alveoli.-In the serous alveoli the cells almost completely fill the cavity, 
so that there is hardly any lumen perceptible. Instead of presenting the clear, 
transparent appearance of the cells of the mucous alveoli, they present a granular 
appearance, due to distinct granules of an albuminous nature embedded in aclosely 
reticulated protoplasm. The ducts which originate from the alveoli are lined at 
their commencement by epithelium which differs little from the pavement type. 
As the ducts enlarge, the epithelial cells change to the columnar type, and the part 
of the cells next the basement-membrane is finely striated. The lobules of the 
salivary glands are richly supplied with blood-vessels which form a dense network 
in the interalveolar spaces. Fine plexuses of nerves are also found in the inter- 
lobular tissue. The nerve-fibrils pierce the basement-membrane of the alveoli, 
and end in branched varicose filaments between the secreting cells. There is no 
doubt that ganglia are to be found in some salivary glands in connection with the 
nerve-plexuses in the interlobular tissue; they are to be found in the submaxillary, 
but not in the parotid. 
In the submaxillary and sublingual glands the lobes are larger and more loosely 
united than in the parotid. 
Mucous Glands.-Besides the salivary glands proper, numerous other glands 
are found in the mouth. They appear to secrete mucus only, which serves to keep 
the mouth moist during the intervals of the salivary secretion, and which is mixed 
with that secretion in swallowing. Many of these glands are found at the posterior 
part of the dorsum of the tongue, behind the circumvallate papillae, and also along 
its margins as far forward as the apex.1 Others lie around and in the tonsil 
1 It has been shown by Ebner that many of these glands open into the trenches around the circumvallate 
papillae, and that their secretion is more watery than that of ordinary mucous glands. He supposes that they 
assist in the more rapid distribution of the substance to be tasted over the region where the special apparatus of 
the sense of taste is situated.-Ed. of 15th English edition. THE SALIVARY GLANDS 
1219 
between its crypts, and a large number are present in the soft palate. These 
glands are of the ordinary compound racemose type. Behind the tip of the 
tongue on each side, external to the anterior extremity of the genio-glossus muscle, 
is a mucous gland, the gland of Nuhn and Blandin (glandula lingualis anterior). 
Its lower surface is partly covered by muscular fibres from the inferior lingualis 
and styloglossus muscles, and it opens by several ducts. 
Surface Form. - The orifice of the mouth is bounded by the lips, two thick, fleshy folds 
covered externally by integument and internally by mucous membrane, and consisting of 
muscles, vessels, nerves, areolar tissue, and numerous small glands. The size of the orifice of 
the mouth varies considerably in different individuals, but seems to bear a close relation to the 
size and prominence of the teeth. Its corners correspond pretty accurately to the outer border 
of the canine teeth. In the Ethiopian tribes the front teeth are large and inclined for- 
ward, the mouth is large; and this, combined with the thick and everted lips which appear to 
be associated with prominent teeth, gives to the negro's face much of the peculiarity by which 
it is characterized. The smaller teeth and the slighter prominence of the alveolar arch of the 
more highly civilized races render the orifice of the mouth much smaller, and thus a small 
mouth is an indication of intelligence, and is regarded as an evidence of the higher civilization 
of the individual. 
Upon looking into the mouth, the first thing we may note is the tongue, the upper surface 
of which will be seen occupying the floor of the cavity. This surface is convex, and is marked 
along the middle line by a raphe which divides it into two symmetrical portions. The anterior 
two-thirds is rough and studded with papillae; the posterior third smooth and tuberculated, 
and covered by numerous glands which project from the surface. Upon raising the tongue 
the mucous membrane which invests the upper surface may be traced covering the sides of the 
under surface, and then reflected over the floor of the mouth on to the inner surface of the 
lower jaw, a part of which it covers. As it passes over the borders of the tongue it changes its 
character, becoming thin and smooth and losing the papillae which are to be seen on the upper 
surface. In the middle line the mucous membrane on the under surface of the tip of the tongue 
forms a distinct fold, the fraenum linguae, by which this organ is connected to the symphysis 
of the jaw. Occasionally it is found that this fraenum is rather shorter than natural, and, 
acting as a bridle, prevents the complete protrusion of the tongue. When this condition exists 
and an attempt is made to protrude the organ, the tip will be seen to remain buried in the 
floor of the mouth, and the dorsum of the tongue is rendered very convex, and more or less 
extruded from the mouth; at the same time a deep furrow' will be noticed to appear in the 
middle line of the anterior part of the dorsum. Sometimes, a little external to the fraenum, 
the ranine vein may be seen immediately beneath the mucous membrane. The corresponding 
artery, being more deeply placed, does not come into view, nor can its pulsation be felt with the 
finger. On either side of the fraenum, in the floor of the mouth, is a longitudinally elevation or 
ridge, produced by the projection of the sublingual gland, which lies immediately beneath the 
mucous membrane. And close to the attachment of the fraenum to the tip of the tongue may 
be seen on either side the slit-like orifices of Whartons ducts, into which a fine probe may be 
passed without much difficulty. By everting the lips the smooth mucous membrane lining them 
may be examined, and may be traced from them on to the outer surface of the alveolar arch. 
Tn the middle line, both of the upper and lower lip, a small fold of mucous membrane passes 
from the lip to the bone, constituting the fraena; these are not so large as the fraenum linguae. 
By pulling outward the angle of the mouth, the mucous membrane lining the cheeks can be 
seen, and on it may be perceived a little papilla which marks the position of the orifice of Sten- 
son's duct-the duct of the parotid gland. The exact position of the orifice of the duct will be 
found to be opposite the second molar tooth of the upper jaw. The introduction of a probe 
into this duct is attended with considerable difficulty. The teeth are the next objects which 
claim our attention upon looking into the mouth. These are, as stated above, ten in either jaw- 
in the temporary set, and sixteen in the permanent set. The gums, in which they are implanted, 
are dense, firm, and vascular. 
At the back of the mouth is seen the isthmus of the fauces, or, as it is popularly called, " the 
throat:" this is the space between the pillars of the fauces on either side, and is the means 
by which the mouth communicates with the pharynx. Above, it is bounded by the soft palate, 
the anterior surface of which is concave and covered with mucous membrane, which is con- 
tinuous with that lining the roof of the mouth. Projecting downward from the middle of 
its lower border is a conical-shaped projection, the uvula. On either side of the isthmus of the 
fauces are the anterior and posterior pillars, formed by the Palato-glossus and Palato-pharyn- 
geus muscles respectively, covered over by mucous membrane. Between the two pillars on either 
side is situated the tonsil. The extirpation of this body is not unattended with danger of 
hemorrhage. Dr. Weir has stated that he believes that when hemorrhage occurs after their 
removal it arises from one of the palatine arteries having been wounded. These vessels are 1220 
THE ORGANS OF DIGESTION 
large: they lie in the muscular tissue of the palate, and when wounded are constantly exposed 
to disturbance from the contraction of the palatine muscles. The vessels of the tonsil, Dr. Weir 
states, are small and lie in the soft tissue, and readily contract when wounded. 
When the mouth is wide open a prominent tense fold of mucous membrane may be seen and 
felt, extending upward and backward from the position of the fang of the last molar tooth 
to the posterior part of the hard palate. This is caused by the pterygo-maxillary ligament, 
which is attached by one extremity to the apex of the internal pterygoid plate, and by the other 
to the posterior extremity of the mylo-hyoid ridge of the lower jaw. It connects the Buccinator 
with the Superior constrictor of the pharynx. The fang of the last molar tooth indicates the 
position of the lingual (gustatory) nerve where it is easily accessible, and can with readiness 
be divided in cases of cancer of the tongue (see page 1043). On the inner side of the last molar 
tooth we can feel the hamular process of the internal pterygoid plate of the sphenoid bone, 
around which the tendon of the Tensor palati plays. The exact position of this process is of 
importance in performing the operation of staphylorrhaphy. About one-third of an inch in 
front of the hamular process, and the same distance directly inward from the last molar tooth, 
is the situation of the opening of the posterior palatine canal, through which emerges the pos- 
terior or descending palatine branch of the internal maxillary artery and one of the descending 
palatine nerves from Meckel's ganglion. The exact position of the opening on the subject may 
be ascertained by driving a needle through the tissues of the palate in this situation, when it 
will be at once felt to enter the canal. The artery emerging from ihe opening runs forward in a 
groove in the bone just internal to the alveolar border of the hard palate, and may be wounded 
in the operation for the cure of cleft palate. Under these circumstances the palatine canal may 
require plugging. By introducing the finger into the mouth the anterior border of the coronoid 
process of the jaw can be felt, and it is especially prominent when the jaw is dislocated. By 
throwing the head well back a considerable portion of the posterior wall of the pharynx may be 
seen through the isthmus faucium, and on introducing the finger the anterior surface of the 
bodies of the upper cervical vertebrae may be felt immediately beneath the thin muscular 
stratum forming the wall of the pharynx. The finger can be hooked around the posterior 
border of the soft palate, and by turning it forward the posterior nares, separated by the 
septum, can be felt, or the presence of any adenoid or other growths in the naso-pharynx can 
be ascertained. 
THE PHARYNX (Figs. 818, 824, 825). 
'Fhe pharynx (from <pdpu^, the throat) is that part of the alimentary canal 
which is placed behind and communicates with the nose, mouth, and larynx. It 
is a musculo-membranous tube, somewhat conical in form, with the base upward 
and the apex downward, extending from the under surface of the skull to the level 
of the cricoid cartilage in front and that of the intervertebral disk between the fifth 
and sixth cervical vertebrae behind. 
The pharynx is about four inches and a half in length, and broader in the trans- 
verse than in the antero-posterior diameter. Its greatest breadth is opposite the 
^cornua of the hyoid bone; its narrowest point, at its termination in the oesophagus. 
It is attached, above, to the periosteum of the petrous portion of the temporal 
bone and of the basilar process of the occipital bone. To the pharyngeal tubercle 
of the basilar process of the occipital bone the raph£ of the Constrictor muscles is 
attached. It is bounded above by the body of the sphenoid as well as by the basilar 
process of the occipital; below, it is continuous with the oesophagus; posteriorly, it 
is connected by loose areolar tissue with the cervical portion of the vertebral 
column and the Longi colli and Recti capitis antici muscles; this areolar tissue is 
contained in what is called the retro-pharyngeal space (spatia retropharyngeus)-, 
anteriorly, it is incomplete, the gap being occupied by the cavities of the nose, 
mouth, and larynx. Anteriorly, it is attached in succession to the Eustachian tube, 
the internal pterygoid plate, the pterygo-maxillary ligament, the posterior termi- 
nation of the mylo-hyoid ridge of the lower jaw, the mucous membrane of the 
mouth, the base of the tongue, hyoid bone, the thyroid and cricoid cartilages; 
laterally, it is connected to the styloid processes and their muscles, and is in con- 
tact with the common and internal carotid arteries, the internal jugular veins, 
and the glosso-pharyngeal, pneumogastric, hypoglossal, and sympathetic nerves, 
and above with a small part of the Internal pterygoid muscles. When the pharynx THE PHARYNX 
1221 
is at rest the anterior and posterior walls are near together. Above the larynx 
they do not come in contact, but leave a channel for air; below the larynx they 
lie in contact, but open for the passage of food. It has seven openings com- 
municating with it-the two posterior nares, the two Eustachian tubes, the 
mouth, larynx, and oesophagus. The pharynx may be subdivided from above 
downward into three parts, nasal, oral, and laryngeal. 
The Nasal Part (pars nasalis pharyngis) (Fig. 824).-The nasal part of the 
pharynx or naso-pharynx lies behind the nose and above the level of the soft palate; 
it differs from the two lower parts of the tube in that its cavity always remains 
patent. In front it communicates through the posterior nares (choanae) (Fig. 825) 
with the nasal fossae. On its lateral wall is the pharyngeal orifice of the Eustachian 
tube (ostium pharyngeum tubae auditivae) (Figs. 822 and 823), which presents the 
appearance of a vertical or triangular cleft bounded above and behind by a firm 
prcminence. The anterior portion of the prominence (labium anterius)is the smaller 
portion. The posterior portion (labium posterius) is large and thick, is called the 
Eustachian cushion (torus tubarius), and is caused by the inner extremity of the car- 
tilage of the tube impinging on the deep surface of the mucous membrane (Fig.823). 
A vertical fold of mucous membrane, the salpingo-pharyngeal fold (plica salpingo- 
SALPINGO- 
NASAL FOLD 
EUSTACHIAN 
CUSHION 
ORIFICE OF 
EUSTACHIAN 
TUBE 
PHARYNGEAL 
BURSA 
SALPINGO-. 
PALATINE FOLD 
ATLAS 
LEVATOR 
CUSHION 
S A LPI N GO-PH A R Y N- 
GEAL FOLD 
Fig. 822.-Pharyngeal tonsil in an adult. 
(Escat.) 
Fig. 823.-The posterior lateral cavity of the naso- 
pharynx. (Escat). 
pharyngea) (Fig- 823), stretches from the lower part of the cushion to the pharynx; 
it contains the Salpingo-pharyngeus muscle. A second and smaller mucous fold 
may be seen stretching from the upper part of the cushion to the palate, the 
salpingo-palatine fold (plica salpingo palatina) (Fig. 823). Behind the orifice of the 
Eustachian tube is a deep recess, the lateral recess or fossa of Rosenmuller (recessus 
pharyngeus) (Fig. 823), which represents the remains of the upper part of the sec- 
ond branchial cleft. The posterior wall of the naso-pharynx is directed upward and 
forward, and it meets the superior wall at an angle. This rounded area of meet- 
ing is the vault of the pharynx (fornix pharyngis). On the posterior wall, at the 
level and above the level of the orifices of the Eustachian tubes, there is a col- 
lection of lymphoid tissue. This is particularly marked in children, and almost 
or quite disappears in the aged. Over it the mucous membrane is thick and 
in folds. This collection of lymphoid tissue is the pharyngeal tonsil (tonsilla 
pharyngea) (Fig. 822). The naso-pharynx communicates with the oral pharynx 
through an aperture between the soft palate and the posterior pharyngeal wall. 
This aperture is the isthmus of the pharynx (isthmus pharyngonasalis). 
The Oral Part (pars oralis pharyngis).-The oral part of the pharynx reaches 
from the soft palate to the level of the hyoid bone. It opens anteriorly, through 
the isthmus faucium, into the mouth, while in its lateral wall, between the two 1222 
THE ORGANS OF DIGESTION 
pillars of the fauces, is the tonsil. A triangular area on the lateral wall is known as 
the sinus tonsillaris (Fig. 824). It is bounded anteriorly by the anterior palatine 
arch, posteriorly by the posterior palatine arch, and below by the side of the 
pharyngeal portion of the tongue. 
The Laryngeal Part (pars laryngea pharyngis).-The laryngeal part of the 
pharynx reaches from the hyoid bone to the lower border of the cricoid cartilage, 
where it is continuous with the oesophagus. In front it presents the triangular 
aperture of the larynx, the base of which is directed forward and is formed by the 
epiglottis, while its lateral boundaries are constituted by the aryteno-epiglottidean 
folds. On either side of the laryngeal orifice is a recess, termed the sinus pyri- 
PHARYNGEAL 
BURSA 
ORIFICE OF 
EUSTACHIAN TUBE 
OPENING OF 
STENSON'S- 
DUCT 
PHARYNGEAL 
TONSIL 
-SOFT PALATE 
NASOPHARYNX 
GENIO- 
HYOGLOSSUS- 
MUSCLE 
ANTERIOR PALA- 
TINE ARCH 
POSTERIOR PALA- 
TINE ARCH 
TONSIL 
CAVITY OF 
PHARYNX 
TONSILLAR 
SINUS 
GENIO-HYOID 
MUSCLE 
POSTERIOR PALA- 
TINE ARCH 
EPIGLOTTIS 
HYOID BONE 
SINUS 
"PYRIFORMIS 
BURSA BENEATH 
HYOID BONE 
ARYTENO- 
EPIGLOTTIC 
FOLD 
CUNEIFORM 
CARTILAGE 
THYROID 
CARTILAGE 
ARYTENOID 
"CARTILAGE 
-OESOPHAGUS 
CRICOID 
CARTILAGE 
RING OF 
TRACHEA 
TRACHEA 
Fig. 824.-Sagittal median section of the head and neck. The head is thrown backward into complete extension, 
which explains the relations between the lower jaw and the hyoid bone as seen in the figure. (Luschka.) 
formis (recessus piriformis) (Fig. 824); it is bounded internally by the aryteno- 
epiglottidean fold, externally by the thyroid cartilage and thyro-hyoid membrane. 
In the anterior part of the sinus pyriformis is a fold (plica nervi laryngei), which 
passes downward and inward. Extending outward from the epiglottis on each 
side is a fold, the pharyngo-epiglottic fold (plica pharyngoepiglottica). This ascends 
in the lateral wall of the pharynx, nearly to the posterior arch of the fauces. 
Structure.-The constrictors of the pharynx (see p. 400) are surrounded by 
a sheath of thin fascia, the bucco-pharyngeal fascia (Cunningham). Forward pro- THE PHARYNX 
1223 
longations of this fascia overlay the Buccinator muscles. The connective tissue of 
the retro-pharyngeal space joins the bucco-pharyngeal fascia to the prevertebral 
fascia, and it is attached by areolar tissue to the other structures to which the 
pharynx is in contact (Cunningham). The pharynx is composed of three coats 
-fibrous, mucous and muscular. 
The Pharyngeal Aponeurosis or Fibrous Coat is situated between the mucous 
and muscular layers. It is thick above, where the muscular fibres are wanting, and 
is firmly connected to the periosteum of the basilar process of the occipital and 
petrous portion of the temporal bones. It is united to the Eustachian tube, pos- 
terior nares, and other points which the pharynx joins. It is thicker above than 
below, and above the sinuses of Morgagni there is no muscular coat, and the wall 
CHOANAE 
VELUM 
TONSIL- 
TONGUE- 
E PIGLOTTIS- 
THYROID 
CARTILAGE 
GLANDS' 
CRICOI D 
Fig. 825.-The anterior surface of the pharynx. (Sappey.) 
of the pharynx is composed of aponeurosis and mucous membrane. As it descends 
it diminishes in thickness, and is gradually lost. It is strengthened posteriorly by 
a strong fibrous band which is attached above to the pharyngeal spine on the under 
surface of the basilar portion of the occipital bone, and passes downward, forming 
a median raphe, which gives attachment to the Constrictor muscles of the pharynx. 
The Mucous Coat (tunica mucosa).-The mucous coat is continuous with that 
lining the Eustachian tubes, the nares, the mouth, and the larynx. In the naso- 
pharynx it is covered by columnar ciliated epithelium; in the buccal and laryngeal 
portions the epithelium is of the squamous variety. Beneath the mucous membrane 
are found racemose mucous glands (glandulae pharyngeae)-, they are especially 
numerous at the upper part of the pharynx around the orifices of the Eustachian 
tubes. Throughout the pharynx are also numerous crypts or recesses, the walls 1224 
THE ORGANS OF DIGESTION 
of which are surrounded by lymphoid tissue similar to that found in the tonsils. 
Across the back part of the pharyngeal cavity, between the two Eustachian tubes, 
a considerable mass of this tissue exists, and has been named the pharyngeal tonsil 
(Fig. 822). Above this in the middle line is an irregular, flask-shaped depres- 
sion of the mucous membrane, extending up as far as the basilar process of the 
occipital bone. It is known as the pharyngeal bursa {bursa pharyngea), and was 
regarded by Luschka as the remains of the diverticulum, which is concerned in 
the development of the anterior lobe of the pituitary body. Other anatomists 
believe that it is connected with the formation of the pharyngeal tonsils. The 
muscular coat {tunica muscularis pharyngis') has been already described (p. 400). 
The sinuses of Morgagni, referred to on a previous page (p. 402 and Fig. 277), 
are intervals between the Superior constrictor muscles and the basilar process 
of the occipital bone. 
The Lymphatic Pharyngeal Ring.-This name was applied by Waldeyer to the 
lymphatic structure gathered into a sort of ring about the pharynx. There are 
three chief collections of this tissue on each side. The first is known as the lingual 
tonsil (p. 1088); the second as the palatine tonsil (p. 1212); and the third as the 
pharyngeal tonsil (p. 1221). 
Surgical Anatomy of the Mouth, Cheeks, Lips, Gums, Tonsils, Palate, Salivary Glands, 
and Pharynx.-The duct of a salivary gland may be blocked by a calculus, and the condition 
is often productive of severe pain. 
A wound of Stenson's duct or of the parotid gland may be followed by a salivary fistula. 
The parotid recess is completely lined by fascia, except above. "Between the anterior edge 
of the styloid process and the posterior border of the external pterygoid muscle there is a gap 
in the fascia, through which the parotid space communicates with the connective tissue about 
the pharynx."1 
This explains why there is frequently swelling of the parotid region in post-pharyngeal abscess. 
A parotid abscess rarely bursts through the skin; it may pass into the temporal fossa, may 
enter the zygomatic fossa, may advance toward the mouth, pharynx, or neck. Because of the 
situation of the gland, a parotid abscess may cause inflammation of the temporo-mandibular 
joint or periostitis of the bone about the meatus, and may even burst into the external auditory 
meatus (Treves). 
The facial nerve passes through the gland, and inflammation or tuberculosis of the gland 
may cause facial palsy. Some enlargements of the parotid region are due to inflammation of 
the parotid lymph-glands, and these glands may become tuberculous. 
Mumps is characterized by acute inflammation of the parotid gland. 
Various tumors occur in the parotid (fibroma, sarcoma, carcinoma, enchondroma, etc.). 
Most parotid tumors contain more or less cartilage. Complete extirpation of the parotid gland 
surgically is certainly extremely difficult, and Treves and others maintain that it is impossible. 
Ranula is a salivary cyst of the floor of the mouth, due to occlusion of ducts of the sublingual 
gland or the duct of the submaxillary gland. Mucous cysts occur in the mouth. A mucous cyst 
of the gland of Nuhn and Blandin is on the under surface of the tongue near the apex. A 
dermoid cyst of the base of the tongue is occasionally encountered. It is of congenital origin. 
What is known as the sublingual bursa is an epithelial-lined space, said to exist between 
the mucous membrane of the floor of the mouth and the Genio-hyo-glossus muscle. When 
acutely inflamed, it produces rapidly a marked swelling called acute ranula. Incomplete 
closure of the oral end of the thyro-glossal duct causes thyro-glossal fistula. If the oral end closes, 
but a portion of the duct below remains unobliterated, a thyro-glossal cyst forms. Such a cyst 
or fistula is always in the median line. The reader will remember that this duct runs from the 
foramen caecum to the isthmus of the thyroid gland. 
Hare-lip is considered on pp. 110 and 111. 
The lower lip, more commonly than any other structure, gives origin to cancer. The upper 
lip is not nearly so often affected. Blocking of mucous glands of the lips causes mucous cysts. 
A scar of the lip or about the lip disturbs this structure and pulls it far out of place. Thus 
great deformity is produced. Burns particularly induce hideous cicatricial contraction. 
Plastic operations in this region are often successful, because of the great vascularity of the 
parts, and because adjacent parts admit of being stretched and pulled in. 
Cleft palate is a by no means rare congenital deformity. The cleft is in the middle line. 
It may be a mere cleft of the uvula, it may be limited to the soft palate, or it may involve 
1 Applied Anatomy. By Sir Frederick Treves. THE O ESO PH A G US 
1225 
the hard palate to but not including the alveolus. It may pass through the alveolus, but if it 
does so it ceases to be median at this point, and follows the line of suture between the incisive 
bone and the superior maxillary (pp. 110 and 111). In a complete cleft palate there is apt 
to be hare-lip at the end of the palate cleft. This cleft in the lip is not median, but is at the 
termination of the palate cleft. If the cleft of a cleft palate runs along each side of the 
incisive bone, the bone is isolated from the superior maxillary. In such a case double hare-lip 
results. 
When a tonsil enlarges it projects inward. The deafness which so often attends hypertrophy 
of the tonsil is not due to blocking of the Eustachian orifice by the tonsil, but is due to thicken- 
ing of the mucous membrane lining the tube itself. The profuse bleeding which sometimes 
follows an operation for the removal of the tonsil is very seldom due to injury of the internal 
carotid artery, but is due to injury of the ascending pharyngeal artery (p. 621) or one of the 
palatine arteries. 
The internal carotid artery is in close relation with the pharynx, so that its pulsations can 
be felt through the mouth. It has been occasionally wounded by sharp-pointed instruments 
introduced into the mouth and thrust through the wall of the pharynx. In aneurism of this 
vessel in the neck the tumor necessarily bulges into the pharynx, as this is the direction in 
which it meets with the least resistance, nothing lying between the vessel and the mucous 
membrane except the thin Constrictor muscle, whereas on the outer side there is the dense 
cervical fascia, the muscles descending from the styloid process, and the margin of the Sterno- 
mastoid muscle. 
The mucous membrane of the pharynx is very vascular, and is often the seat of inflamma- 
tion, frequently of a septic character, and dangerous on account of its tendency to spread to the 
larynx. On account of the tissue which surrounds the pharyngeal wall being loose and lax, the 
inflammation is liable to spread through it far and wide, extending downward into the posterior 
mediastinum along the oesophagus. Abscess may form in the connective tissue behind the 
pharynx, between it and the vertebral column, constituting what is known as retro-pharyngeal 
abscess. This is most commonly due to caries of the cervical vertebrae, but may also be caused 
by suppuration of a lymphatic gland which is situated in this position opposite the axis, and 
which receives lymphatics from the nares, or by gumma or by acute pharyngitis. In these 
cases the pus may be easily evacuated by an incision, with a guarded bistoury, through the 
mouth, but, for aseptic reasons, it is desirable that the abscess should be opened from the neck. 
In some instances this is perfectly easy; the abscess can be felt bulging at the side of the neck 
and merely requires an incision for its relief; but this is not always so, and then an incision 
should be made along the posterior border of the Sterno-mastoid and the deep fascia should 
be divided. A director is now to be inserted into the wound, the forefinger of the left hand 
being introduced into the mouth and pressure made upon the swelling. This acts as a guide, 
and the director is to be pushed onward until pus appears in the groove. A pair of sinus forceps 
are now inserted along the director and the opening into the cavity dilated. 
Foreign bodies not infrequently become lodged in the pharynx and most usually at its termi- 
nation at about the level of the cricoid cartilage, just beyond the reach of the finger, as the 
distance from the arch of the teeth to the commencement of the oesophagus is about six inches. 
Hypertrophy of the adenoid tissue of the naso-pharynx produces groups of hypertrophic 
masses known as adenoids. A child with adenoids has a cough, and when awake or asleep, 
breathes noisily and with the mouth open. The voice is muffled, the hearing is impaired, the 
expression is vacant, the mind is dull, and the tonsils are enlarged. 
THE OESOPHAGUS (Figs. 826, 827, 828, 829). 
The oesophagus (ooo, 01010, 1 carry; qa-pito, to eat) or gullet is a muscular 
canal, averaging about nine or ten inches in length, extending from the pharynx 
to the stomach. It commences at the upper border of the cricoid cartilage, oppo- 
site the intervertebral disk between the fifth and sixth cervical vertebrae descends, 
along the front of the spine through the posterior mediastinum, passes through 
the Diaphragm, and, entering the abdomen, terminates in the stomach wall at the 
point known as the cardia opposite the tenth dorsal vertebra or possibly opposite 
the intervertebral disk between the tenth and eleventh dorsal vertebrae. The 
general direction of the oesophagus is vertical, but it presents two or three slight 
curves in its course. At its commencement it is placed in the median line, but 
it inclines to the left side as far as the root of the neck, gradually passes to the 
middle line again, and finally again deviates to the left as it passes forward to 1226 
THE ORGANS OF DIGESTION 
the oesophageal opening of the Diaphragm (hiatus oesophageus). The oesophagus 
also presents an antero-posterior flexure, corresponding to the curvature of the 
cervical and thoracic portions of the spine. It is the narrowest part of the alimen- 
tary canal, being most contracted at its commencement and at the point where 
it passes through the Diaphragm. 
The diameter of the largest portion of the oesophagus where it is contracted is 
about half an inch; when it is fully dilated, an inch or even more. 
In the neck the oesophagus, when at rest, is flattened, the anterior and posterior 
walls approaching each other. The canal in the neck is round or oval, and the 
lumen is stellate (Cunningham). The oesophagus is somewhat constricted at three 
points. One constriction is at the very beginning of the tube; another is where 
the left bronchus crosses it; another is at the point where the oesophagus passes 
through the Diaphragm. The tube at each constricted point is distinctly flattened. 
The diameter of each of these constricted parts is slightly under one-half inch, 
the diameter of the rest of the tube when contracted is one-half inch, but when 
dilated may reach or exceed one inch. The average distance from the upper 
AZYGOS VEIN 
PULMONARY 
ARTERY 
BRONCHUS 
(ESOPHAGUS 
AORTA 
PLEURA 
Fig. 826.-Pleural cul-de-sac of the posterior mediastinum. 
incisor teeth to the beginning of the gullet is about six inches; the average dis- 
tance from the incisor teeth to the cardiac opening of the stomach is fifteen or 
sixteen inches. The portion of the oesophagus which is in the neck is called 
the cervical portion (pars cervical is); the portion in the thorax, the thoracic portion 
(pars thoracalis), and the portion which lies in the oesophageal opening of the 
Diaphragm, the diaphragmatic portion. The margin of the oesophageal orifice is 
narrow in front, thicker behind and to the sides. Behind and to the sides the 
diaphragmatic portion of the oesophagus is about half an inch in length. In 
front there is only a thin edge of Diaphragm in contact with the gullet. The 
oesophagus is connected to the margins of the diaphragmatic orifice by connec- 
tive tissue. The so-called abdominal portion of the oesophagus (pars abdominalis) 
is not over half an inch in length, and is limited to the small portion of the ante- 
rior and left lateral surface observed when a stomach which is completely 
empty is drawn downward with considerable force. The abdominal portion of 
the oesophagus is covered with peritoneum; the corresponding portions of the 
right lateral and posterior walls are not covered by peritoneum. This uncov- 
ered portion of the oesophagus runs downward and to the left and lies directly THE OESOPHAGUS 
1227 
behind the oesophageal groove on the posterior surface of the left lobe of the 
liver, but does not actually touch the groove, which in reality holds the thick, 
right edge of the oesophageal opening of the Diaphragm. When the stomach is 
distended the abdominal portion of the gullet ceases to exist and becomes part 
of the stomach wall. 
Relations.-In the neck the oesophagus is in relation, in front, with the trachea, 
and it is connected to the posterior wall of the trachea by areolar tissue. At the 
lower part of the neck, where it projects to the left 
side, it is in relation in front with the thyroid gland 
and thoracic duct; behind, it rests upon the vertebral 
column and Longi colli muscles; on each side, it is in 
relation with the common carotid artery (especially the 
left, as the gullet inclines to that side) and part of the 
lateral lobes of the thyroid gland; the recurrent laryn- 
geal nerves ascend between it and the trachea. 
In the thorax, it is at first situated a little to the left 
of the median line; it then passes behind the aortic 
arch, being separated from it by the trachea, and de- 
scends in the posterior mediastinum, along the right 
side of the aorta, nearly to the Diaphragm, where it 
passes in front and a little to the left of the artery, 
previous to entering the abdomen. It is in relation, 
in front, with the trachea, the arch of the aorta, the 
left common carotid and left subclavian arteries, which 
incline toward its left side, the left bronchus, the 
pericardium, and the Diaphragm; behind, it rests 
upon the vertebral column, the Longi colli muscles, 
the right intercostal arteries, and the vena azygos 
minor; and below, near the Diaphragm, upon the front 
of the aorta; laterally, it comes in contact with both 
pleurae, especially with the left pleura above and the 
right pleura below; it overlaps the vena azygos major, 
which lies on its right side, while the descending aorta 
is placed on its left side. The pneumogastric nerves 
descend in close contact with it, the right nerve pass- 
ing down behind, and the left nerve in front of it, each 
nerve spreading out into a plexus, the oesophageal 
plexus, around the tube. The two plexuses are joined 
to each other. The right nerve forms the posterior 
oesophageal plexus (plexus oesophageus posterior); 
the left nerve the anterior oesophageal plexus (plexus 
oesophageus anterior). 
In the lower part of the posterior mediastinum the 
thoracic duct lies to the right side of the oesophagus ; higher up, it is placed 
behind it, and, crossing about the level of the fourth dorsal vertebra, is continued 
upward on its left side. 
Above the aortic arch and the arch of the great azygos vein above the root 
of the right lung, the pleurae are close to but not in actual contact with the 
oesophagus. 
Below the arch of the great azygos vein the right side of the oesophagus is 
covered with pleura nearly to the diaphragmatic opening. The posterior surface 
of the gullet also may be covered with pleura. Below the arch of the aorta on 
the left side the pleura covers only a small portion of the oesophagus, that is, a 
portion of the left wall, a little above the diaphragmatic opening. 
-OESOPHAGUS 
-TRACHEA 
AORTA 
DIAPHRAGM 
Fig. 827.-The supports of the 
oesophagus at the aorta in an in- 
fant. (Poirier and Charpy.) THE ORGANS OF DIGESTION 
1228 
Anomalies.-There may be openings of the oesophagus into the trachea. A 
diverticulum or pressure pouch may exist. Such a pouch is usually placed upon 
the posterior wall near the pharynx. There may be congenital constriction, tubular 
or annular. 
Structure.- The oesophagus is fastened to adjacent structures by connective 
tissue called the* tunica adventitia. The tube has three coats-an external or 
muscular, a middle or areolar, and an internal or mucous coat. 
The Muscular Coat (tunica muscularis).-The muscular coat is composed of two 
planes of fibres of considerable thickness, an external plane of longitudinal and 
an internal plane of circular fibres. 
SUPERIOR 
CERVICAL 
GANGLION 
-PHARYNX 
INTERNAL. 
CAROTID 
ARTERY 
SUPERIOR LARYN- 
GEAL NERVE 
THYROID. 
BODY 
VAGUS NERVE 
COM MON 
CAROTID 
ARTERY 
INTERNAL 
'jugular vein 
TRACHEA 
IN FERIOR 
THYROID ARTERY 
RECURRENT 
NERVE 
.SU BC LAVICU LAR 
ARTERY 
AORTA' 
RIGHT CEPHALIC 
TRUNK 
OESOPHAGUS 
VAGUS NERVE 
LEFT 
PULMONARY 
ARTERY 
-AZYGOS VEIN 
LEFT BRONCHI 
LEFT LUNG 
BRONCHIAL 
ARTERY 
THORACIC CANAL* 
RIGHT PUL- 
MONARY VEIN 
VAGUS NERVE 
RIGHT LUNG 
PLEURA 
INFERIOR 
VENA CAVA 
AZYGOS VEIN 
DIAPHRAGM 
Fig. 828.-The position and relation of the oesophagus in the cervical region and in the posterior mediastinum. 
Seen from behind. (Poirier and Charpy.) 
The Longitudinal Fibres are arranged, at the commencement of the tube, in three 
fasciculi: one in front, which is attached to the vertical ridge on the posterior 
surface of the cricoid cartilage; and one at each side, which is continuous with 
the fibres of the Inferior constrictor of the pharynx ; as they descend they 
blend together and form a uniform laver, which covers the outer surface of the 
tube. 
Accessory slips of muscular fibres are described by Cunningham as passing 
between the oesophagus and the left pleura (m. pleurooesophageus), where it covers 
the thoracic aorta, or between the oesophagus and the root of the left bronchus 
(m. bronchooesophageus), or the back of the pericardium, as well as other still more THE OESOPHAGUS 
1229 
rare accessory fibres. In rig. 829, taken from a dissection in the Museum of the 
Royal College of Surgeons of England, several of these accessory slips may be seen 
passing from the oesophagus to the pleura, and two slips passing to the back of 
the trachea just above its bifurcation. These slips of muscular fibres which pass 
to adjacent structures give support to the oesophagus. Below, the longitudinal 
fibres of the oesophagus are continued into the longitudinal fibres of the stomach. 
The Circular Fibres are continuous above with the Inferior constrictor of the 
pharynx; their direction is transverse at the upper and lower parts of the tube, 
but oblique in the central part. Below, the circular fibres pass into the circular 
and oblique fibres of the stomach. 
The muscular fibres in the upper part of the oesophagus are of a red color, and 
consist chiefly of the striped variety, but below they consist for the most part of 
involuntary muscular fibre. At the cardia they act 
as a sphincter to solid food. Some maintain that 
this sphincter is closed tonically, others that it opens 
and closes rhythmically during gastric digestion. 
The Submucous or Areolar Coat (tela submucosa).- 
The submucous or areolar coat connects loosely the 
mucous and muscular coats. It consists of dense 
connective tissue and contains blood-vessels, nerves, 
and oesophageal glands (glandulae oesophageae). The 
glands are mucous glands and are found through- 
out the length of the gullet. The ducts of the glands 
pass through the muscularis mucosae. These ducts 
are surrounded by adenoid tissue. 
The Mucous Coat (tunica mucosa).-The mucous 
coat is thick, of a reddish color above and pale 
below. It is disposed in longitudinal folds, which 
disappear on distention of the tube. Its surface is 
studded with minute papillae, and is covered through- 
out with a thick layer of stratified pavement epithe- 
lium. The mucous coat contains glands which differ 
from the mucous glands of the submucous tissue. 
They are branched and tubular (Hewlett) and are 
called the superficial glands. There are two chief 
groups of superficial glands; one near the beginning, 
and the other near the termination of the oesophagus, 
fhe ducts of the superficial glands are not sur- 
rounded by lymphoid tissue (Hewlett). Beneath the 
mucous membrane, between it and the submucous 
coat, is a layer of longitudinally arranged non-striped 
muscular fibres. This is the muscularis mucosae 
(lamina muscularis mucosae). At the commencement 
it is absent, or only represented by a few scattered 
bundles; lower down it forms a considerable stratum. 
Vessels of the Oesophagus.-The larger vessels are in the submucosa and send 
branches to the mucosa and muscularis. The arteries supplying the oesophagus 
are derived from the inferior thyroid branch of the thyroid axis of the subclavian, 
from the descending thoracic aorta and the bronchial arteries, and from the gastric 
branch of the coeliac axis, and from the left inferior phrenic of the abdominal aorta. 
They have for the most part a longitudinal direction. The veins are gathered into 
a plexus on the outer surface of the oesophagus. This plexus receives the venous 
blood from the walls of the tube. From the lower portion of the plexus branches 
go to the coronary vein of the stomach. Higher up branches go to the azygos veins 
Fig. 829. - Accessory muscular 
fibres between the oesophagus and 
pleura, and oesophagus and trachea. 
(From a preparation in the Museum 
of the Royal College of Surgeons of 
England.) 1230 
THE ORGANS OE DIGESTION 
and thyroid veins. In this manner a communication is opened between the portal 
veins and the systemic veins. 
Lymphatics of the Oesophagus.-The lymphatics drain into the inferior deep 
cervical glands and the glands of the posterior mediastinum. 
Nerves of the Oesophagus.-The nerves are derived from the pneumogastric and 
from the sympathetic; they form a plexus in which are groups of ganglion-cells 
between the two layers of the muscular coats. From this fibres pass to supply 
the muscle, and others go to the submucous tissue to form a secondary plexus. 
It is usual to regard the plexus as consisting of two parts, an anterior oesophageal 
plexus, derived from the left pneumogastric, and a posterior oesophageal plexus, 
derived from the right pneumogastric. These two plexuses are in the posterior 
mediastinum; they communicate with each other and contain sympathetic fibres. 
Movements and Innervation of the Oesophagus. 
Movements.-When liquid is swallowed it is, as pointed out by Kronecker and Meltzer, 
suddenly forced into the gullet by the contraction of the Mylo-hyoid muscle, the tube playing 
a practically passive part.1 In the passage of solid and semisolid food the oesophagus con- 
tracts. It does not contract, as was once thought, in sections, but there is a peristaltic wave. 
''The wave at a given point lasts in the neck region about 3.5 seconds, and from five 
to nine seconds in the thoracic region.2 The lower end of the oesophagus or cardia has a 
sphincter, the cardiac sphincter. It is usually taught that this sphincter is tonieally contracted. 
When a mouthful of food is swallowed it rests above the sphincter for a moment and is then 
forced through by muscular contractions (Kronecker and Meltzer). If several acts of swallow- 
ing follow each other rapidly the sphincter relaxes so that there is no resistance to the passage 
of food. In cats Dr. Walter B. Cannon3 has demonstrated "rhythmical relaxations of the 
cardia, so that fluid food streams from the stomach into the oesophagus even above the level 
of the heart, then is pressed into the stomach again by a peristaltic wave, only to be released 
a moment later to pour into the oesophagus anew." 
Innervation.-There is in the oesophagus a local reflex, but peristalsis is dominated by the 
central nervous system. "It seems probable that the peristaltic contractions of the oesophagus, 
to be efficient, must be supported by nervous influences from outside. In this respect the 
oesophagus is different from the remainder of the alimentary canal."4 
Surgical Anatomy.-The relations of the oesophagus are of considerable practical interest 
to the surgeon, as he is frequently required, in cases of stricture of this tube, to dilate the canal 
by a bougie, when it is of importance that the direction of the oesophagus and its relations 
to surrounding parts should be remembered. In cases of malignant disease of the oesophagus, 
where its tissues have become softened from infiltration of the morbid deposit, the greatest 
care is requisite in directing the bougie through the strictured part, as a false passage may easily 
be made, and the instrument may pass into the mediastinum, or into one or the other pleural 
cavity, or even into the pericardium. 
The student should also remember that obstruction of the oesophagus, and consequent 
symptoms of stricture, are occasionally produced by aneurism of some part of the aorta press- 
ing upon the tube. In such a case the passage of a bougie could only hasten the fatal issue. 
In passing a bougie the left forefinger should be introduced into the mouth and the epiglottis 
felt for, care being taken not to throw the head too far backward. The bougie is then to be 
passed beyond the finger until it touches the posterior wall of the pharynx. The patient is 
now asked to swallow, and at the moment of swallowing the bougie is passed gently down- 
ward, all violence being carefully avoided. 
It occasionally happens that a foreign, body becomes impacted in the oesophagus and can 
neither be brought upward nor moved downward. When all ordinary means for its removal 
have failed, and the body is lodged above the lower one-third of the gullet, external oesopha- 
gotomy is performed. If the foreign body is lodged in the lower one-third of the gullet the 
stomach is opened {gaslrotomy) and the foreign body is extracted. If the foreign body is 
allowed to remain lodged in the oesophagus, extensive inflammation and ulceration may 
ensue. In one case the foreign body ultimately penetrated the intervertebral substance, and 
destroyed life by inflammation of the membranes and substance of the cord. 
The operation of oesophagotomy is thus performed: The patient being placed upon his 
back, with the head and shoulders slightly elevated, an incision, about four inches in length, 
1 Recent Advances in the Knowledge of the Movements and Innervation of the Alimentary Canal. By Walter 
B. Cannon, M.D., in Medical News, May 20, 1905. 
= Ibid. 3 Ibid. « Ibid. THE ABDOMEN 
1231 
should be made on the left side of the trachea, from the thyroid cartilage downward, dividing 
the skin, Platysma, and deep fascia. The edges of the wound being separated, the Omo-hyoid 
muscle should, if necessary, be divided, and the fibres of the Sterno-hyoid and Sterno-thyroid 
muscles drawn inward; the sheath of the carotid vessels, being exposed, must be drawn out- 
ward, and retained in that position by retractors: the oesophagus will now be exposed, and 
should be divided over the foreign body, which can then be removed. Great care is necessary 
to avoid wounding the thyroid vessels, the thyroid gland, and the laryngeal nerves. 
'rhe oesophagus may be obstructed not only by foreign bodies, but also by changes in its 
coats, producing stricture, or by pressure on it from without of new-growths or aneurism, etc. 
The different forms of stricture are: (1) the spasmodic, occurring in neurotic individuals, and 
intermittent in character, so that the dysphagia is not constant. Spasmodic stricture of the 
oesophagus sometimes occurs in cases of cancer of the stomach and cancer of the liver; 
(2) fibrous, due to cicatrization after injuries, such as swallowing corrosive fluids or boiling 
water; and (3) malignant, usually epitheliomatous, in its nature. Cancer is most common 
either at the upper end of the tube, opposite to the cricoid cartilage, or at its lower end at the 
cardiac orifice. Cicatricial stricture may be treated by gradual dilatation. If a stricture is 
impassible from above, the stomach may be opened, an instrument passed from below, and a 
string used to divide the stricture. 
The operation of oesophagostomy has occasionally been performed in cases where the stric- 
ture in the oesophagus is at the upper part, with a view to making a permanent opening below 
the stricture through which to feed the patient, but the operation has been far from a suc- 
cessful one, and the risk of setting up diffuse inflammation in the loose planes of connective 
tissue deep in the neck is so great that it would appear to be better, if any operative interference 
is undertaken, with the idea of forming a mouth to introduce food, to perform gastrostomy. 
The operation of oesophagostomy is performed in the same manner as oesophagotomy, but the 
edges of the opening in the oesophagus are stitched to the skin incision. Gastrostomy is 
the only operation to be thought of in malignant stricture. 
THE ABDOMEN. 
rhe abdomen (from abdo, I put away or hide, or possibly from adeps, fat) is 
the largest cavity in the body. It is of an oval form, the extremities of the oval 
being directed upward and downward; the upper one being formed by the under 
surface of the Diaphragm, the lower by the upper concave surface of the Levator 
ani muscles. In order to facilitate description, it is artificially divided into two 
parts: an upper and larger part, the abdomen proper; and a lower and smaller 
part, the pelvis. These two cavities are not separated from each other, but the 
limit between them is marked by the brim of the true pelvis. The space is wider 
alw)ve than below, and measures more in the vertical than in the transverse 
diameter. 
The abdomen proper differs from the other great cavities of the body in being 
bounded for the most part by muscles and fasciae, so that it can vary in capacity 
and shape according to the condition of the viscera which it contains; but, in 
addition to this, the abdomen varies in form and extent with age and sex (Fig. 
S31). In the adult male, with moderate distention of the viscera, it is oval or 
barrel-shaped, but at the same time flattened from before backward. In the adult 
female, with a fully developed pelvis, it is conical with the apex above, and in 
young children it is conical with the apex below. 
Boundaries.-The boundary between the thorax and abdomen is the Dia- 
phragm. This muscle forms a dome over the abdomen, and the cavity extends 
high into the bony thorax, reaching to the level of the junction of the fourth costal 
cartilages with the sternum. The lower end of the abdomen is limited by the 
structures which clothe the inner surface of the bony pelvis, principally the Leva- 
tores ani and Coccygei muscles on either side. These muscles are sometimes 
termed the Diaphragm of the pelvis. The abdomen proper is bounded in front and 
at the sides by the lower ribs, the abdominal muscles, and the venter ilii; behind, 
by the vertebral column and the Psoas and Quadratus lumborum muscles; above, 
by the Diaphragm; below, by the brim of the pelvis. The muscles forming the 1232 
THE ORGANS OF DIGESTION 
boundaries of the cavity are lined upon their inner surface by a layer of fascia, 
differently named, according to the part which it covers. 
Fig. 830.-Topography of thoracic and abdominal viscera. THE ABDOMEN 
1233 
The abdomen contains (Fig. 830) the greater part of the alimentary canal; 
some of the accessory organs to digestion-viz., the liver and pancreas, the spleen, 
the kidneys, and suprarenal capsules. Most of these structures, as well as the 
wall of the cavity in which they are contained, are covered by an extensive and 
complicated serous membrane, the peritoneum (Fig. 853.) 
The Apertures in the Walls of the Abdomen.-The apertures found in the walls of 
the abdomen, for the transmission of structures to or from it, are the umbilicus, for 
the transmission (in the foetus) of the umbilical vessels; the caval opening in the 
Diaphragm, for the transmission of the inferior vena cava; the aortic opening, for 
the passage of the aorta, vena azygos major, and thoracic duct; and the oesophageal 
opening, for the oesophagus and pneumogastric nerves. Below, there are two 
apertures on each side: one for the passage of the femoral vessels, and the other 
for the transmission of the spermatic cord in the male, and the round ligament in 
the female. 
Male Type 
Infantile Type 
Female Type 
A BO 
Fig. 831. - Schematic outlines of the abdomen. 
Regions (Fig. 832).-For convenience of description of the viscera, as well as 
of reference to the morbid conditions of the contained parts, the abdomen is arti- 
ficially divided into nine regions. Thus, if two circular lines are drawn around 
the body, the one through the extremities of the ninth ribs where they join their 
costal cartilages, and the other through the highest points of the crests of the ilia, 
the abdominal cavity is divided into three zones-an upper, a middle, and a 
lower. If two parallel lines are drawn perpendicularly upward from the centre of 
Poupart's ligament, each of these zones is subdivided into three parts-a middle 
and two lateral.1 
The middle region of the upper zone is called the epigastric (hi, over; p/rfp, 
the stomach)', and the two lateral regions, the right and left hypochondriac (6^0, 
under; the cartilages). The central region of the middle zone is the 
mesogastric or umbilical; and the two lateral regions, the right and left lumbar. The 
middle region of the lower zone is the hypogastric or pubic region; and the lateral 
regions are the right and left inguinal or iliac. The viscera contained in these 
different regions are the following (Fig. 832): 
1 Anatomists are far from agreed as to the best method of subdividing the abdominal cavity. Cunningham 
suggests that, the lower line should encircle the body on a level with the highest point of the iliac crest, as seen 
from the front-a point corresponding with a prominent tubercle on the outer lip of the iliac crest about two 
inches behind the anterior superior spine. Addison (Journal of Anatomy and Physiology, vols. xxxiv. and 
xxxv.), in a careful analysis of the abdominal viscera in forty subjects, adopts the following lines : (1) a 
median, from the symphysis pubis to the ensiform cartilage; (2) two lateral lines drawn vertically through a point 
midway between the anterior superior iliac spine and the symphysis pubis ; (3) an upper transverse line half-way 
between the symphysis pubis and the suprasternal notch; and (4) a lower transverse line midway between the 
last and the upper border of the symphysis pubis.-Ed. of 15th English edition. 
Joessel draws a line through the cartilaginous ends of the tenth ribs: a line through the two anterior superior 
spines of the ilia. On each side he carries a perpendicular line from the iliopectineal eminence to the hori- 
zontal line connecting the tenth ribs. By this plan the highest plane is subcostal. THE ORGANS OF DIGESTION 
1234 
Right Hypochondriac. 
The greater part of the 
right lobe of the liver, 
the hepatic flexure of the 
colon, and part of the 
right kidney. 
Epigastric Region. 
The greater part of the 
stomach, including both 
cardiac and pyloric ori- 
fices, the left lobe and 
part of the right lobe of 
the liver and the gall- 
bladder, the pancreas, the 
duodenum, the* supra- 
renal capsules, and parts 
of the kidneys. 
Left Hypochondriac. 
The fundus of the 
stomach, the spleen, the 
extremity of the pancreas, 
the splenic flexure of the 
colon, and part of the 
left kidney. 
Right Lumbar. 
Ascending colon, part 
of the right kidney, and 
some convolutions of the 
small intestines. 
Umbilical Region. 
The transverse colon, 
part of the great omentum 
and mesentery, transverse 
part of the duodenum, 
and some convolutions of 
the jejunum and ileum, 
and part of both kidneys. 
Left Lumbar. 
Descending colon, part 
of the omentum, part of 
the left kidney, and some 
convolutions of the small 
intestines. 
Right Inguinal or Iliac. 
The caecum and ver- 
miform appendix and a 
portion of the ascending 
colon. 
Hypogastric Region. 
Convolutions of the 
small intestines, the blad- 
der in children, and in 
adults if distended, and 
the uterus during preg- 
nancy. 
Left Inguinal or Iliac. 
Sigmoid flexure of the 
colon and a portion of 
the descending colon. 
If the anterior abdominal wall is reflected in the form of four triangular flaps 
by means of vertical and transverse incisions-the former from the ensiform car- 
tilage to the symphysis pubis, the latter from flank to flank at the level of the 
umbilicus-the abdominal or peritoneal cavity is freely opened into and the 
contained viscera are in part exposed.1 
Above and to the right side is the liver, situated chiefly under the shelter of 
the right ribs and their cartilages, but extending across the middle line, and reach- 
ing for some distance below the level of the ensiform cartilage. Below and to the 
left of the liver is the stomach, from the lower border of which an apron-like fold 
of peritoneum, the great omentum, descends for a varying distance, and obscures, 
to a greater or lesser extent, the other viscera (Fig. 861). Below it, however, some 
of the coils of the small intestine can generally be seen, while in the right and left 
iliac regions respectively the caecum and the sigmoid flexure of thecolon are exposed. 
'The bladder occupies the anterior part of the pelvis, and, if distended, will project 
above the symphysis pubis; the rectum lies in the concavity of the sacrum, but 
is usually obscured by the coils of the small intestine. 
If the stomach is followed from left to right it will be found to be continuous 
with the first part of the small intestine, or duodenum, the point of continuity being 
marked by a thickened ring which indicates the position of the pyloric valve. 
The duodenum passes toward the under surface of the liver, and then, curving 
downward, is lost to sight. If, however, the great omentum be thrown upward 
1 It must be borne in mind that, although the term abdominal cavity is used, there is, under normal con- 
ditions, only a potential cavity or lymph-space, since the viscera are everywhere in contact with the parietes.- 
Ep. of 15th English edition. THE ABDOMEN 
1235 
over the chest, the terminal part of the duodenum will be observed passing across 
the spine toward the left side, where it becomes continuous with the coils of the 
small intestine. These measure some twenty feet in length, and if followed down- 
ward will be seen to end in the right iliac fossa by opening into the caecum, the 
commencement of the large intestine. From the caecum the large intestine takes 
an arched course, passing at first upward on the right side, then across the middle 
line and downward on the left side, and forming respectively the ascending, trans- 
verse, and descending parts of the colon. In the left iliac region it makes still 
another bend, the sigmoid flexure, and then follows the curve of the sacrum as 
far as the rectum. 
Fig. 832.- The regions of the abdomen anil their contents. Edge of costal cartilages in dotted outline 
The spleen lies behind the stomach in the left hypochondriac region, and may 
be in part exposed by pulling the stomach over toward the right side. 
The glistening appearance of the deep surface of the abdominal wall and of 
the exposed viscera is due to the fact that the former is lined and the latter more 
or less completely covered by a serous membrane, the peritoneum. 
Development of the Alimentary Canal, Viscera and Peritoneum.-When 
the paraxial mesoblast of the embryo has developed a series of transverse seg- 
mentations it becomes converted into a row of dark, square segments known as 
the protovertebrae or the mesoblastic somites, which are separated by clear, trans- 
verse intervals. They appear first in the region that is to become the neck, and 
from there extend back along the entire length of the trunk. These bodies are 
not solely the representatives of the future permanent vertebrae, but differentiate 
partly into muscles and true skin. 
On each side of the protovertebrae the lateral mesoblast splits into two layers. 1236 
THE ORGANS OF DIGESTION 
The upper layer is applied to the epiblast, and forms with it the somatopleure or 
body-wall. The lower layer becomes adherent to the hypoblast, and forms the 
splanchnopleure or wall of the alimentary canal. The space between these two 
layers is the caelfm or the pleuroperitoneal cavity. This body-cavity is of large 
size in the early stages of the development of the embryo. 
Anteriorly-or, if the body is in the erect posture, superiorly-there is developed 
a comparatively large space called the pericardiothoracic cavity; and a transverse 
fold develops, which marks off this cavity from the future abdominal cavity. This 
fold, with many veins of large size, develops into the primary Diaphragm, although 
its dorsal part remains incomplete. The dorsal part is completed at a later period, 
constituting the Diaphragm as we see it in the adult. As Dr. Frederick J. Brock- 
way expresses it: "The Diaphragm is thus made up of a ventral, younger part, and 
a dorsal, older part. When this posterior part fails to develop, there is opportunity 
for a congenital diaphragmatic hernia to be present." 
The pericardiothoracic cavity becomes divided into three cavities, and the two 
lateral ones are for a time continuous with the abdominal cavity, This continuation 
is, however, but temporary, and they are afterward separated. In this manner, 
four large serous sacs are formed. The two lateral thoracic sacs are known as 
Fig. 833.-Diagrammatic outline of a longitudinal vertical section of the chick on the fourth day. ep. Epi- 
blast. xm. Somatic mesoblast, hy. Hypoblast, m. Visceral mesoblast, of. Cephalic fold. pf. Caudal fold. 
am. Cavity of true amnion, ys. Yolk-sac. i. Intestine, s. Fore-gut. a. Future anus, still closed, m. The 
mouth, me. The mesentery, al. The allantoic vesicle, pp. Space between inner and outer folds of amnion. 
(From Quain's Anatomy, Allen Thomson.) 
the pleural sacs, and are lined with the pleura; the median thoracic sac is the 
pericardial sac, and is lined with the pericardium; and the abdominal sac forms the 
abdominal cavity, and is lined with the peritoneum. 
The primitive alimentary canal, which was formed early by the closure within 
the embryo of a portion of the blastodermic vesicle, consists of three parts: first, 
the fore-gut, within the cephalic flexure, dorsal to the heart; second, the mid-gut, 
opening freely into the yolk-sac; and third, the hind-gut, within the caudal flexure. 
In the fore-gut are developed the back portion of the mouth, the tongue, the 
pharynx, the oesophagus, the stomach, the larger part of the duodenum, and the 
organs that have grown out from these structures. The hind-gut forms a portion 
of the colon and the rectum, with the exception of the latter's anal end; and the 
mid-gut gives rise to the remainder of the digestive tube. 
Development of the Alimentary Canal.-The fore-gut and hind-gut end 
blindly, there being at first neither mouth nor anus (Figs. 833 and 834). The upper 
part of the fore-gut becomes dilated to form the pharynx, in relation to which the 
branchial arches are developed (Fig. 836); the succeeding part remains tubular, 
and with the descent of the stomach is elongated to form the oesophagus. Soon 
a fusiform dilatation, the future stomach, makes its appearance, and beyond 
this the mid-gut opens freely into the yolk-sac (Figs. 836 and 837). 
This opening is at first wide, but, as the body-walls close in around the umbilicus, 
it is gradually narrowed into a tubular stalk, the yolk-stalk or vitello-intestinal duct. THE ABDOMEN 
1237 
At this stage, therefore, the alimentary canal forms a nearly straight tube in front 
of the notochord and primitive aorta (Fig. 834). From the stomach to the rectum 
A m n i o n 
Neural Canal 
"Allantois 
Yolk-stalk 
Hind-gut 
Fore-gut' 
Heart 
Chorda Dorsalis 
Yolk-sac 
Fig. 834.-Diagram of a longitudinal section of a mammalian embryo. Very early. (After Quain.) 
it is attached to the notochord by a band of mesoblast, from which the common 
mesentery of the gut is subsequently developed. The stomach undergoes a further 
dilatation, and its two curvatures can be recognized (Figs. 838 and 841), the 
greater directed toward the verte- 
bral column and the lesser toward 
the anterior wall of the abdomen, 
while of its two surfaces one looks 
to the right and the other to the left. 
The mid-gut also undergoes great 
elongation, and forms a V-shaped 
loop which projects downward and 
forward; from the bend or angle of 
the loop the vitello-intestinal duct 
passes to the umbilicus (Fig. 841). 
For a time a part of the loop ex- 
tends beyond the abdominal cavity 
into the umbilical cord, but by 
the end of the third month this 
is withdrawn. With the length- 
ening of the tube, the mesoblast, 
which attaches it to the future ver- 
tebral column and which carries the 
blood-vessels for the supply of the 
gut, is thinned and drawn out to 
form the primitive or common me- 
sentery. The portion of this mesentery which is attached to the greater curva- 
ture of the stomach is named the mesogastrium, and the parts which suspend 
Fig. 835.-Early form of the alimentary canal. In A a 
front view and in B an antero-posterior section are repre- 
sented. a. Four pharyngeal or visceral plates. b. The 
pharynx. C, c. The commencing lungs. d. The stomach, 
J, f- The diverticula connected with the formation of the 
liver. g. The yolk-sac into which the middle intestinal groove 
(From oiiiker, THE ORGANS OF DIGESTION 
1238 
the colon and rectum are respectively termed the mesocolon and mesorectum 
(Fig. 841). About the sixth week a lateral diverticulum makes its appear- 
ance a short distance beyond the vitello-intestinal duct, and indicates the future 
caecum or boundary between the small and the large intestine. This caecal divertic- 
ulum has at first a uniform calibre, but its blind extremity remains rudimentary 
and forms the vermiform appendix (Figs. 841 and 842). Changes also take place 
in the position and direction of the stomach. It falls over on to its right sur- 
face, which henceforth is directed backward, while its original left surface looks 
forward; further, its greater curvature is drawn downward and to the left, away 
from the vertebral column, while its lesser curvature is directed upward, and the 
commencement of the duodenum is pushed over to the right side of the middle 
line. The mesogastrium, being attached to the greater curvature, must necessarily 
follow its movements, and hence it becomes greatly elongated and drawn outward 
Cerebellum. 
Midbrain. 
/Optic vesicle. 
Pharyngeal septum. 
Stomodaeum. 
Auditory pit. 
Pharynx. 
Ventricle. 
Aortic bulb. 
Stomach.- 
Liver. 
Mid-gut and yolk 
stalk. 
Cloacal dilatation 
of hind-gut. 
.Hind-gut. 
Allantoic stalk 
Umbilical vein 
Allantois. 
Umbilical artery. 
Fig. 836.-Human embryo, about fifteen days old. Brain and heart represented from right side ; 
alimentary canal and yolk-sac in mesial section. (After His.) 
from the vertebral column, and, like the stomach, what was originally its right 
surface is now directed backward and its left forward. In this way a pouch, the 
bursa omentalis, is formed behind the stomach; this pouch is the future lesser sac 
of the peritoneum, and it increases in size as the alimentary tube undergoes further 
development; the entrance to the pouch constitutes the future foramen of Winslow 
(Figs. 838, 842, and 845). The remainder of the mid-gut becomes greatly 
increased in length, so that the tube is coiled on itself, and this increase in length 
demands a corresponding increase in the width of the intestinal attachment of 
the mesentery, so that it becomes plaited or folded. 
At this stage the small and the large intestines are attached to the vertebral 
column by a common mesentery, the coils of the small intestine falling to the right 
of the middle line, while the large intestine lies on the left side.1 
' Sometimes this condition persists throughout life, and it is then found that the duodenum does not cross 
from the right to the left side of the vertebral column, but lies entirely on the right side of the mesial plane, 
where it is continued into the jejunum ; the arteries to the small intestine (rami intestini tenuis) also arise from 
the right instead of the left side of the superior mesenteric artery. THE ABDOMEN 
1239 
The gut now becomes rotated upon itself, so that the large intestine is carried 
over in front of the small intestine, and the caecum is placed immediately below 
Rathke's pouch 
(pituitary involution). 
Notochord. 
Mandibular 
arch. 
Lung diver-, 
ticulum. 
Stomach. 
Liver. 
Opening into 
yolk sac. 
Allantois.- 
■Blind portion of 
hind-gut. 
-Wolffian duct. 
A 
Median rudiment of 
thyroid gland 
Lung diverticulum. 
(Esophagus. 
Mandibular arch. 
■Notochord. 
Rathke's 
pouch 
(pituitary 
involution). 
Stomach.- 
Pancreas. 
Bile duct. 
Omphalo- 
mesenteric1 
duct. 
Allantois. 
Blind portion of 
hind-gut. 
■Wolffian duct. 
Fig. 837. -Sketches in profile of two stages in the development of the human alimentary canal. 
Fig. A X 30. Fig. B X 20. (His.) 
the liver; about the sixth month the caecum descends into the right iliac fossa, 
and the large intestine now forms an arch consisting of the ascending, transverse, 
and descending portions of the colon-the transverse portion crossing in front 1240 
THE ORGANS OF DIGESTION 
of the duodenum and lying just below the greater curvature of the stomach; 
within this arch the coils of the small intestine are disposed (Fig. 842). Some- 
times the downward progress of the caecum is arrested, so that in the adult it 
may be found lying immediately below the liver instead of in the right iliac region. 
Trachea.- 
(Esophagus. 
-Lung. 
Trachea. 
■Lung. 
Stomach. 
(Esophagus. 
■ Pancreas. 
Pile duct 
■Stomach. 
Bile duct. 
Pancreas. 
Csecum. 
\l-shaped loop 
of mid-gut.' 
Cloaca. 
Vitello-intestinal duct.- 
Cloaca.■ 
Fig. 838. -Front view of two successive stages in the development of the alimentary canal. (His.) 
Further changes take place in the bursa omentahs and in the common mesen- 
tery, and give rise to the peritoneal relations seen in the adult. The bursa omen- 
talis, which at first reaches only as far as the greater curvature of the stomach, 
grows downward to form the great omentum, 
and this downward extension lies in front of 
the transverse colon and the coils of the small 
intestine. The anterior layer of the transverse 
mesocolon is at first quite distinct from the poste- 
rior wall of the bursa omentalis, but ultimately 
Kight 
suprarenal 
capsule 
Livev 
Liver- 
Right 
■suprarenal 
capsule 
Lesser , 
omentum 
Stomach- 
Lesser 
omentum 
Stomach 
Left 
.suprarenal 
capsule 
' Left 
suprarenal 
capsule 
Liver. 
Liver 
Fig. 839.-Schematic and enlarged cross-section through 
the body of a human embryo in the region of the mesogas 
trium. Beginning of third month. (Toldt.) 
Fig. 840.-Same section as in Fig. 661 at end 
of third month. (Toldt.) 
the two blend, and hence the great omentum appears as if attached to the trans- 
verse colon (Figs. 845, 846, and 847). The mesentery of the duodenum, in which THE ABDOMEN 
1241 
the rudiment of the pancreas is enclosed, disappears, and so this part of the gut 
becomes fixed to the posterior abdominal wall, and the pancreas lies entirely 
behind the peritoneal membrane. The mesenteries of the ascending and descend- 
•Aorta. 
Anterior part of mesogastrium. 
Spleen. 
Mesogastrium. 
■Coeliac axis. 
Pancreas. 
Duodenum.- 
Superior mesenteric 
artery. 
•Mesentery. 
Caecum.- 
.-.Inferior mesenteric artery. 
Hind-gut. 
Fig. 841.-Abdominal part of alimentary canal and its attachment to the primitive or common mesentery. 
Human embryo of six weeks. (After Toldt.) (From Kollmann's Entwickelungsgeschichte.) 
ing parts of the colon disappear in the majority of cases, while that of the small 
intestine assumes the oblique attachment characteristic of its adult condition. 
The small omentum is formed by a thinning of the mesoblast or anterior primitive 
mesentery, which attaches the lesser curvature of the stomach to the anterior 
abdominal wall. By the subsequent growth of the liver this leaf of mesoblast is 
Meso- 
gastrium.- 
Meso- 
gastrium. 
Greater 
* curvature 
of stomach. 
Bile-duct. ■ 
Greater 
'curvature 
of stomach. 
Duodenum. 
.Great omen- 
tum. 
Duodenum.' 
Mesentery.- 
Great 
omentum. 
Point where 
■ intestinal 
loops cross 
each other. 
Caecum.- 
Point where 
intestinal- 
loops cross 
each other. 
Mesocolon. ■ 
Mesocolon. 
Small . 
intestine. 
Large in- 
testine. 
Caecum. 
Vermiform' 
appendix.. 
Large intes- 
' tine. 
Small intes- 
tine- 
Yolk-stalk.. 
Mesentery. 
Rectum. 
Yolk-stalk. 
Rectum. 
Fig. 842.-Illustrating two stages in the development of the human alimentary canal and its mesentery. 
The arrow indicates the entrance to the bursa omentalis. 
divided into two parts-viz., the small omentum between the stomach and liver 
and the falciform ligament between the liver and the abdominal wall and Dia- 
phragm (Fig. 844). 1242 
THE ORGANS OF DIG EST JON 
Phe anus is developed as a slight invagination of the epiblast a short distance 
in front of the posterior end of the hind-gut. This invagination is termed the 
proctodaeum, the mesoblast between it and the hypoblastic lining of the hind- 
gut is thinned, and ultimately the septum breaks down and disappears, and the 
hind-gut opens on the surface; into this part of the hind-gut the urinary and 
generative organs open for a time, and so constitutes a common cloaca. 'The 
small portion of the hind-gut behind the orifice of the anus is named the caudal 
or post-anal gut; it communicates with the neural tube by means of a canal, the 
neurenteric canal, already referred to. Ultimately the 
post-anal gut becomes obliterated, and it, together with 
the neurenteric canal, finally disappears. 
The peritoneal cavity is the space left between the 
visceral and parietal layers of the mesoblast, and the 
serous membrane is develped from these layers. 
The tongue originates from the floor of the pharynx. 
The anterior or papillary portion first appears as a 
rounded elevation, the tuberculum impar, between the ven- 
tral ends of the mandibular and hyoid arches (Fig. 848). 
Between the third and fourth arches a second larger 
elevation arises, in the centre of which is a median groove 
or furrow. This second elevation is termed the furcula, 
and from it the epiglottis is developed, while the median 
furrow becomes the entrance to the larynx (Fig. 849). 
The tuberculum impar and the furcula are at first in 
apposition, but are soon separated by a ridge produced 
by the forward growth of the second and third arches. 
This ridge gives rise to the posterior part of the tongue 
and extends forward in the form of a V, so as to em- 
brace between its two limbs the tuberculum impar. At 
the apex of the V there is a pit-like invagination to form 
the middle thyroid rudiment, and this depression persists 
as the foramen caecum of the adult. The union of the 
two parts of the tongue is indicated even in the adult 
by a V-shaped depression, the apex of which is at the 
Fig. 843. - Final disposition 
of the intestines and their vas- 
cular relations. A. Aorta. H. 
Hepatic artery. S. Splenic art- 
ery. M., Col. Branches of supe- 
rior mesenteric artery, m, m'. 
Branches of inferior mesenteric 
artery. (Jonnesco.) 
Septum transversum. 
Liver. 
Aorta. 
Mesogastrium 
(posterior part). 
Mesogastrium 
(anterior part) 
Stomach. 
Umbilical vein. 
Intestinal 
V-shaped loop. 
Umbilical cord. 
Mesentery. 
Colon. 
Fig. 844. - The primitive mesentery of a six weeks' human embryo, half schematic. (Kollmann.) 
foramen caecum, while the two limbs run outward and forward parallel to but 
a little behind the circumvallate papillae, which are therefore developed from THE ABDOMEN 
1243 
the tuberculum impar (Figs. 848, 849, and 850). The tonsils are developed from 
the second branchial cleft, and make their appearance between the fourth and 
fifth months. 
The liver arises in the form of two diverticula or hollow outgrowths from the 
ventral surface of that portion of the fore-gut which afterward becomes the 
Mesogastrium. 
anterius. 
Liver.- 
■Bursa omentalis. 
Umbilical vein.. 
Border of the anterior, 
mesogastrium. 
Pancreas. 
Mesogastrium 
posterius. 
Duodenum. 
Stomach.' 
Great omentum. 
■Transverse 
mesocolon. 
Transverse colon. 
Fig. 845.-Schematic figure of the bursa omentalis etc Human embryo of eight weeks. (Kollmann.) 
duodenum (Figs. 836 and 837). The outgrowths, which represent the right and 
the left lobes, respectively, of the adult liver, give off solid buds of cells, which grow 
into columns or cylinders; these unite with one another in every direction to form 
a close network, in the meshes of which are contained the capillar^ blood-vessels. 
Diaphragm 
Liver 
Lesser omentum 
Stomach 
Pancreas 
Anterior lamella of greater omentum 
Greater curvature 
Transverse mesocolon 
Duodenum 
Posterior lamella of greater omentum 
Transverse colon 
Mesentery 
Greater omentum 
Small intestine 
Fig. 846. -Illustrating the development of the bursa omentalis, cavity of the great omentum or lesser sac. 
Feet al stage. * Lesser sac. (Hertwig.) 
Some of these columns become hollowed out and form the bile-ducts, while the 
remainder constitute the secreting structure. The minute ducts thus produced 
unite to form the right and left hepatic ducts; while the common bile-duct is devel- 
oped as a protrusion from the duodenal wall, and as it grows the liver becomes 
shifted away from the duodenum. The gall-bladder and cystic duct are formed by 1244 
THE ORGANS OF DIGESTION 
a hollow evagination from the wall of the common bile-duct. About the third 
month the liver almost fills the abdominal cavity. From this period the relative 
Diaphragm 
■Liver 
Lesser omentum 
Stomach- 
Pancreas 
Posterior lamella of greater omentum- 
Greater curvature 
Part of omentum enclosing pancreas 
Transverse mesocolon 
Transverse colon 
Duodenum 
Mesentery 
Greater omentum 
Small intestine 
Fig. 847. - Development of bursa omentalis. Infantile stage. Great omentum covers the intestines and has 
fused with the transverse mesocolon. Pancreas is free from peritoneum posteriorly. (Hertwig.) 
development of the liver is less active, more especially that of the left lobe, which 
now becomes smaller than the right; but up to the end of foetal life the liver 
remains relatively larger than in the adult. 
Mandibular arch. 
Tuberculuni 
impar 
Hyoid arch. 
Furcula 
Third arch. 
F ourth arch. 
Fig. 848.-The floor of the pharynx of a human embryo about fifteen days old. X 50. (From His.) 
The pancreas is also an early formation, being far advanced in the second 
month. It originates as a hollow projection from the hypoblast of the dorsal wall 
of the duodenum (Figs. 837 and 838), opposite the hepatic diverticula, which, as 
Tuberculum impar 
(papillary part of tongue). 
Posterior part of tongue. 
/Furcula. 
.Mandibular arch. 
■Hyoid arch. 
Entrance to larynx. 
■Third arch. 
■Fourth arch. 
Lung. 
Fig. 849.-The floor of the pharynx of a human embryo about twenty-three days old. X 30. (From His.) 
we have already seen, spring from its ventral wall. This hollow process grows 
between the two layers of the dorsal mesentery and sends out offshoots, which THE PERITONEUM 
1245 
branch abundantly and form a complicated tubular gland. As torsion of the 
stomach takes place, the pancreas assumes a transverse position and becomes fixed 
across the dorsal wall of the abdomen, the posterior layer of its mesentery under- 
going absorption. Its duct ultimately opens into the duodenum together with the 
common bile-duct. 
The spleen, on the other hand, is of mesoblastic origin, for there is never anv 
connection between the intestinal cavity and the substance of this organ. It 
originates in the mesenteric fold which connects the stomach to the vertebral 
column (mesogastrium) (Fig. 841). 
Papillary portion of tongue. 
■Mandibular arch. 
Hyoid arch. 
Foramen caecum. 
Posterior part 
of tongue. 
Third arch. 
Fig. 850. -Floor of mouth of an embryo slightly older than that shown in Fig. 849. X 16. (From His.) 
THE PERITONEUM (TUNICA SEROSA). 
During life and in the uncut corpse the peritoneal cavity (cavum peritonaei} is 
air-tight. It is not a real cavity, as muscular tension and atmospheric pressure 
permit no vacant space to form. When the surgeon or anatomist opens the 
abdomen, the peritoneal cavity is at that moment produced. 
The peritoneum (from nepc, about, and teiImo, I stretch} is the largest serous 
membrane in the body, and consists, in the male, of a closed sac, a part of which 
is applied against the abdominal parietes, while the remainder is reflected over 
the contained viscera. In the female the peritoneum is not a closed sac, since the 
free extremities of the Fallopian tubes open directly into the peritoneal cavity. 
The portion of the peritoneum applied against the abdominal parietes consti- 
tutes the parietal peritoneum; the portion reflected over the viscera, the visceral 
peritoneum. 'The free surface of the membrane is smooth, covered by a layer of 
flattened endothelium, and lubricated by a small cavity of serous fluid. Hence 
the viscera can glide freely against the wall of the cavity or upon one another with 
the least possible amount of friction. Its attached surface is rough, being con- 
nected to the viscera and inner surface of the parietes by means of areolar tissue 
termed the subserous areolar tissue (tela subserosa}. The parietal portion is loosely 
connected with the fascia lining the abdomen and pelvis, but more closely to the 
under surface of the Diaphragm and also in the middle line of the abdomen. 
The peritoneum differs from the other serous membranes of the body in pre- 
senting a much more complex arrangement-an arrangement which can only 
be clearly understood by following the changes which take place in the alimentary 
canal during its development; and therefore the student is advised to preface his 
study of the peritoneum by reviewing the remarks on Embryology. 
Structure of the Peritoneum.-It is a thin, glistening serous membrane and 
consists of a connective-tissue layer and one layer of flat endothelial cells upon the 
free surface of the membrane. The connective-tissue layer consists of bundles of 
connective tissue which contain many connective-tissue cells and elastic fibres. 
It contains a multitude of lymph-spaces, lymph-vessels, and lymph-capillaries. 1246 
THE ORGANS OF DIGESTION 
Beneath the peritoneum is a layer of lax and spongy connective tissue which serves 
to bind the serous membrane to parts beneath. This layer is called the subserous 
connective tissue. In some regions it is plentiful; in others, as over the liver and 
intestine, it is very scantily developed. The endothelial cells are flat and polyg- 
onal. Some hold that they are joined together by cement-substance. Byron 
Robinson asserts that there is no cement-substance, but rather an organized con- 
nection between the protoplasmic processes of adjacent cells. 
On the surface of the endothelium between the cells numerous apertures or 
interruptions are to be seen. Some of these, the stomata, are surrounded by a 
ring of cubical endothelium (Fig. 851), and communicate with lymphatic capil- 
laries ; others, the stigmata or 
pseudostomata, are mere interrup- 
tions in the endothelial layer, and 
are occupied by processes of the 
branched connective-tissue cor- 
puscle of the subjacent tissue. 
Stomata are particularly numer- 
ous in the region of the Dia- 
phragm and are relatively scanty 
in the1 region of the pelvis. 
The amount of fluid contained 
in the closed sac is, in most 
cases, only sufficient to moisten 
the surface, but not to furnish any 
appreciable quantity of liquid. 
When a small quantity can be 
collected, it is found to resemble 
lymph, and, like that fluid, coagu- 
lates spontaneously; but when 
secreted in large quantities, as 
in dropsy, it is a more watery 
fluid, but still contains a con- 
siderable amount of proteid which is coagulated on boiling. 
The peritoneum is a lymph-sac and its walls contain a great quantity of lym- 
phatic structures. In the subserous tissue the numerous lymph-spaces obtain 
fluid from the peritoneal cavity by way of the stomata of the endothelial coat, 
and from these lymph-spaces lymph-vessels take origin. Byron Robinson points 
out that the lymphatic system of the peritoneum consists of: 1. Interstitial 
lymph-spaces. 2. Non-valved capillaries. 3. Valved lymphatic channels. The 
subendothelial interstitial lymph-spaces intercommunicate and can take up an 
immense quantity of fluid from the peritoneal cavity. Normally the spaces contain 
both nutrient material and waste products. Through these spaces blood capil- 
laries pass, and from these spaces lymph-capillaries come. Lymphatics are par- 
ticularly plentiful in-1, the tendinous portion of the Diaphragm; 2, the ligamenta 
lata; 3, the omentum; 4, the ventral surface of the small intestine; 5, the liver and 
spleen.1 
The lymph from this region reaches the mediastinal or diaphragmatic glands. 
The serous surface of the Diaphragm is the region chiefly efficient in absorption 
from the peritoneum, and there is a current in the peritoneal cavity directed toward 
the Diaphragm.2 Absorption is very rapid from the peritoneal cavity. Fluid equalling 
from 3 to 8 per cent, of the body-weight can be absorbed in one hour. There are a 
multitude of nerves in the peritoneum, and it seems probable that each endothelial 
Fig. 851.-Part of peritoneal surface of the central tendon of 
Diaphragm of rabbit, prepared with nitrate of silver, s. Stomata. 
Z. Lymph-channels, t. Tendon-bundles. The stomata are sur- 
rounded by germinating endothelial cells. (From Handbook for 
the Physiological Laboratory, Klein.) 
1 The Peritoneum. By Byron Robinson. ~ Ibid. THE PERITONEUM 
1247 
cell receives a nerve ending. The minute arteries of the peritoneum are surrounded 
by nerve-plexuses. According to Byron Robinson,1 thenervesof the peritoneum are: 
1. Medullated. 2. Non-medullated. 3. Fibres of Remak. 4. The Vater-Pacinian 
corpuscles and other varieties of nerve endings. 5. Nerve-cells. The visceral 
peritoneum contains many more nerves than the parietal peritoneum. 
The parietal peritoneum (peritonaeum parietale) lines the wall of the abdominal 
cavity. The visceral peritoneum (peritonaeum viscerate) covers the viscera. Back 
of the parietal peritoneum is a space, the retro-peritoneal space (spatium retro- 
peritonaeale), which contains the great vessels and nerves, the suprarenal cap- 
sules, the kidney, and ureters (Figs. 853, 854, 855, 856, and 857J. 
We describe the peritoneum as consisting of two sacs, a greater sac and a lesser sac 
(Fig. 853). The larger part of the abdominal cavity is lined by the greater sac, as most 
of the viscera are covered by it The lesser sac is placed largely behind the stomach. 
These two sacs are not two distinct cavities which communicate. They constitute 
one cavity, a portion of which has been formed into a diverticulum or recess by a 
process of constriction, the result of changes produced in the position of adjacent 
viscera by development. Prof. Birmingham says: " If the great sac be compared 
to a bag, the lesser sac might be represented as a pocket lying behind, and open- 
ing into it by a narrow orifice, the foramen of Winslow, on its posterior wall."2 
'The greater sac lines the walls of the abdominal cavity and covers the viscera 
which are invested by peritoneum, except the posterior portion of the stomach, 
the suprarenal capsule of the left side, the superior surface of the pancreas, the 
Spigelian lobe and the caudate lobes of the liver, and portions of the spleen, left 
kidney, and transverse colon, which are covered by peritoneum of the lesser sac.3 
To trace the continuity of the membrane from one viscus to another, and from 
the viscera to the parietes, it is necessary to follow its reflections in the vertical 
and horizontal directions, and in doing so it matters little where a start is made. 
If the stomach is drawn downward, a fold of peritoneum will be seen stretching 
from its lesser curvature to the transverse fissure of the liver (Figs. 853 and 859). 
This is the gastro-hepatic or lesser omentum (omentum minus), and consists of two 
layers; these, on being traced downward, split to envelop the stomach, covering 
respectively its anterior and posterior surfaces. At the greater curvature of the 
stomach they again come into contact and are continued downward in front of 
the transverse colon, forming the anterior two layers of the great or gastro-colic 
omentum (omentum majus) (Figs. 853 and 861). Reaching the free edge of this fold 
they are reflected upward as its two posterior layers, and thus the great omentum 
consists of four layers of peritoneum. Followed upward the two posterior layers 
separate so as to enclose the transverse colon, above w hich they once more come into 
contact and pass backward to the abdominal wall as the transverse mesocolon 
(mesocolon transversum) (Fig. 853). Reaching the abdominal wall about the level of 
the transverse part of the duodenum, the two layers of the transverse mesocolon 
become separated from each other and take different directions; the upper or ante- 
rior layer, known as the ascending layer of the transverse mesocolon, ascends in front 
of the pancreas, and its further course will be followed presently (Fig. 853). The 
lower or posterior layer is carried downward, as the anterior layer of the mesentery, 
by the superior mesenteric vessels to the small intestine, around which it may be 
followed and subsequently traced upward as the posterior layer of the mesentery to 
the abdominal wall. From the posterior abdominal wall it sweeps downward over 
the aorta into the pelvis, where it invests the first part of the rectum and attaches it 
to the front of the sacrum by a fold termed the mesorectum (Fig. 863, p. 1259). 
Leaving first the sides and then the front of the second part of the rectum it is 
reflected on to the back of the bladder, and, after covering the posterior and 
' The Peritoneum. By Byron Robinson. 
8 Ibid. 
2 Prof. Cunningham's Text-book of Human Anatomy. 1248 
THE ORGANS OF DIGESTION 
upper aspects of this viscus, is carried by the urachus and obliterated hypogastric 
arteries as folds, on to the posterior surface of the anterior abdominal wall (Fig. 
852). The fold upon the urachus is the plica urachi {plica umbilicalis media)', 
the fold on each obliterated hypogastric artery is the plica hypogastrica {plica 
umbilicalis lateralis). Between the rectum and bladder it forms a pouch, the 
recto-vesical pouch (excavatio rectovesicalis), bounded on the sides by two cres- 
centic or semilunar folds {plicae r ectoves icales), which pass from the posterior 
surface of the bladder to the sides of the rectum; the bottom of this pouch is 
about on a level with the middle of the vesiculae seminales-i. e., three inches or 
so from the orifice of the anus. When the bladder is distended the peritoneum 
is carried up with the expanded viscus, so that a considerable part of the anterior 
surface of the latter lies directly against the abdominal wall without the inter- 
vention of the peritoneal membrane. When the bladder is empty the peri- 
toneum forms a transverse fold over its upper surface {plica vesicalis transversa). 
In the female the peritoneum is reflected from the rectum on to the upper part 
of the posterior vaginal wall, forming the recto-vaginal pouch or pouch of Douglas 
{excavatio rectout er ina) (Fig. 853). In the pouch of Douglas are two folds of peri- 
toneum {plica rectouter inae), which begin at the posterior surface of the cervix, 
extend back to the sides of the rectum, and bound above the deepest portion of the 
pouch. The pouch is then carried over the posterior aspect and fundus of the uterus 
on to its anterior surface, which it covers as far as the junction of the body and 
cervix uteri, forming here a second but shallower depression, the utero-vesical 
pouch {excavatio vesico liter ina). It is also reflected from the sides of the uterus to 
the lateral wall of the pelvis on each side as an expanded fold, the broad ligament of 
the uterus (ligamenum latum uteri), in the free margin of each broad ligament can 
be felt a thickened cord-like structure, the Fallopian tube (tuba uterina [Fallopii]). 
When the peritoneum lining the anterior abdominal wall is examined from 
behind, it is noticed that certain structures which lie in front of it form five peri- 
toneal ridges (Fig. 852). The structure in the middle line is the urachus, which is 
the remains of the foetal allantois. In the adult it is a fibrous cord which passes from 
the umbilicus to the summit of the bladder. This cord is slender above, but broader 
below. External to the urachus are the fibrous cords which resulted from oblit- 
eration of the hypogastric arteries {arteriae umbilicales). These cords become more 
slender as they ascend toward the sides of the urachus and pass to the umbilicus. 
More external still are the folds formed by the deep epigastric arteries. The fold 
over each epigastric artery is the plica epigastrica; the fold over each obliterated 
hypogastric artery is the plica umbilicalis lateralis; the fold over the obliterated 
urachus is the plica umbilicalis media. 
The five peritoneal ridges formed by the above-named structures create three 
peritoneal fossae on each side, called the inguinal fossae or pouches (fovea inguinales). 
The external inguinal fossa (fovea inguinalis lateralis) is external to the deep epi- 
gastric artery and corresponds to the internal abdominal ring. There is a funnel- 
shaped depression in its floor marking the point at which the inguinal process 
passed down. This depression, if marked, predisposes to oblique inguinal hernia. 
The middle inguinal fossa (fovea inguinalis medialis) is placed between the deep 
epigastric arteries and the obliterated hypogastric vessels. The internal inguinal 
fossa or the supravesical fossa (fovea supravesicalis) is between the obliterated 
hypogastric artery and the urachus. Just beneath the inner termination of Pou- 
part's ligament there is another fossa, the femoral or crural fossa (fovea femoralis), 
which corresponds to the situation of the femoral ring. The obliterated hypo- 
gastric artery is to the inner side of this fossa. 
On following the parietal peritoneum upward on the back of the anterior 
abdominal wall it is seen to be reflected around a fibrous band, the ligamentum 
teres or obliterated umbilical vein (Figs. 855,856, and 857), which reaches from the THE PERITONEUM 
1249 
umbilicus to the under surface of the liver. Here the membrane forms a somewhat 
triangularfold, the falciform or suspensory ligament of the liver {ligamentum jalcij or me 
hepatis), which attaches the upper and anterior surfaces of that organ to the Dia- 
phragm and abdominal wall. With the exception of the line of attachment of this 
ligament the peritoneum covers the under surface of the anterior part of the Dia- 
phragm and is reflected from it on to the upper surface of the liver as the anterior or 
superior layer of the coronary ligament {ligamentum coronarium hepatis anterior). 
Covering the upper and anterior surfaces of the liver it is reflected around its sharp 
margin on to its under surface as far as the transverse fissure, where it is continuous 
Plica umbilicalis 
lateralis 
Plica umbilicalis 
media 
Plica 
epigastriea' 
Peritoneum 
Iliacus 
muscle 
Poupart's 
ligament 
Crural 
nerve' 
External 
-inguinal 
fossa 
External 
iliac artery' 
External 
iliac vein 
Femoral 
fossa 
Vas 
deferens 
Middle 
''inguinal 
fossa 
Deep 
inguinal 
fossa 
Superior 
vesical 
artery 
Bladder 
Fig. 852.-Posterior view of the abdominal wall in its lower half. The peritoneum is in place and the 
various cords are shining through. (Joessel.) 
with the anterior layer of the small omentum from which a start was made (Fig- 853). 
The posterior layer of this omentum is carried backward from the transverse fissure 
over the under surface and Spigelian lobe of the liver, and is then reflected, as the 
posterior or inferior layer of the coronary ligament (ligamentum coronarium hepatis 
posterior), on to the Diaphragm and is prolonged downward over the pancreas to 
become continuous with the ascending layer of the transverse mesocolon (Fig. 853). 
Between the two layers of the coronary ligament there is a triangular surface of the 
liver which is devoid of peritoneum; it is named the bare area of the liver, and is 
attached to the Diaphragm by connective tissue. If, however, the two layers of the THE ORGANS OF DIGESTION 
1250 
coronary ligaments are traced toward the right and left margins of the liver, they 
approach each other, and, ultimately fusing, they form the right and left lateral 
ligaments of the liver and attach its right and left lobes respectively to the Dia- 
phragm. 
If the small omentum is followed toward the right side it is seen to form a 
distinct free edge around which its anterior and posterior layers are continuous 
with each other and between which are situated the portal vein, hepatic artery, and 
bile-duct. If the finger is introduced behind this free edge, it passes through a 
somewhat constricted ring, the foramen of Winslow (foramen epiploicum [JFww- 
lowi\) (Figs. 853, 855, and 858). This is the communication between what are 
termed the greater and lesser sacs of the peritoneum and has the following bound- 
aries: in front, the free edge of the gastro-hepatic omentum. This free edge is 
called the ligamentum hepatoduodenale. The gastro-hepatic omentum has the 
portal vein, hepatic artery, and bile-duct between its two layers (Fig. 859); behind 
the foramen of Winslow is the vena cava inferior; above, are the Spigelian and 
caudate lobes of the liver; below, the duodenum and the hepatic artery, as the latter 
passes forward and upward from the coeliac axis. 
The lesser peritoneal cavity or the lesser sac of the peritoneum (bursa omentalis) 
(Figs. 853, 855, and 858), therefore, lies behind the small omentum and has the 
following dimensions: above, it is limited by the portion of the liver which lies 
behind the transverse fissure; below, it extends downward into the great omentum, 
reaching, in the foetus, as far as its free edge (Fig. 846); in the adult, however, its 
vertical extent is limited by adhesions between the layers of the omentum. In front, 
it is bounded by the small omentum, stomach, and anterior two layers of the great 
omentum; behind, by the two posterior layers of the great omentum, the transverse 
colon, and ascending layer of the transverse mesocolon which passes upward in front 
of the pancreas as far as the posterior surface of the liver. Laterally the lesser 
sac reaches from the foramen of Winslow on the right side as far as the spleen on 
the left (recessus lienalis) (Fig. 860), where it is limited by the lieno-renal liga- 
ment. The extent of the lesser sac and its relations to surrounding parts can be 
definitely made out by tearing through the small omentum and inserting the 
hand through the opening thus made. A passage (vestibulum bursae omentalis) 
leads out from the foramen of Winslow over the head of the pancreas to the left as 
far as the median vascular gastro-pancreatic fold (plica gastropancreatica) (Fig. 858). 
This fold carries the gastric artery and the coronary vein. From the vestibule 
there is a narrow and upward prolongation behind the lesser omentum and cau- 
date lobe of the liver and in front of the lumbar portion of the Diaphragm. 
This prolongation is the superior omental recess (recesszis superior omentalis). 
The chief part of the lesser peritoneal cavity extends downward from the gastro- 
pancreatic fold and is called the inferior omental recess (recessus omentalis infe- 
rior). The constriction which separates the two recesses is due to the passage 
around the lesser sac and to the front of the gastric and hepatic arteries. "The 
former winds around its left side, the latter around its right, and each raises up a 
fold of peritoneum which projects strongly into the sac and partially divides it 
into two."1 A small projection of the lesser sac passes to the right side behind 
the beginning of the duodenum. The splenic artery in its course to the spleen 
lies back of the posterior layer of the lesser sac. 
It should be stated that during a considerable part of foetal life the transverse 
colon is suspended from the posterior abdominal wall by a mesentery of its own- 
the two posterior layers of the great omentum passing, at this stage, in front of and 
above the colon (Fig. 846). This condition sometimes persists throughout adult 
life, but as a rule adhesion occurs between the mesentery of the transverse colon 
1 Prof. Cunningham's Text-book of Human Anatomy. THE PERITONEUM 
1251 
and the posterior layer of the great omentum, with the result that the colon 
appears to receive its peritoneal covering by the splitting of the two posterior 
layers of the latter fold. 
In addition to tracing the peritoneum vertically, it is necessary to trace it hori- 
zontally (Figs. 854, 855, 856, and 857). If this is done below the transverse colon, 
the circle is extremely simple, as it includes only the greater sac of the peri- 
toneum (Fig. 854). Above the level of the transverse colon the arrangement is 
more complicated, on account of the existence of the two sacs. 
Starting from the linea alba, below the level of the transverse colon, and tracing 
the continuity in a horizontal direction to the right, the peritoneum covers the 
internal surface of the abdominal wall almost as far as the anterior border of 
the Quadratus lumborum muscle; it encloses the caecum, and is reflected over the 
SMALL SAC 
LESSER 
OMENTUM' 
FORAMEN OF WINSLOW, 
WITH ARROW PASSED 
THROUGH IT 
STOMACH- 
PANCREAS 
TRANSVERSE 
MESOCOLON 
THIRD PART OF 
DUODENUM 
GREAT 
OMENTUM' 
TRANSVERSE 
COLON 
MESENTERY 
SMALL 
INTESTINE- 
UTERUS. 
RECTUM 
POUCH OF 
DOUGLAS 
Fig. 853.-Diagrammatic mesial section of the female body, to show the peritoneum on vertical tracing. The 
great sac of the peritoneum is black and is represented as being much larger than in nature; the small sac is very 
darkly shaded; the peritoneum on section is shown as a white line, and a white arrow is passed through the fora- 
men of Winslow from the great into the small sac. (Cunningham.) 
sides and anterior surface of the ascending colon, fixing it to the abdominal wall, 
from which it can be traced over the kidney to the front of the bodies of the ver- 
tebrae. It then passes along the mesenteric vessels to invest the small intestine, 
and back again to the spine, forming the mesentery, between the layers of which 
are contained the mesenteric blood-vessels, nerves, lacteals, and glands. Lastly, 
it passes over the left kidney to the sides and anterior surface of the descending 
colon, and, reaching the abdominal wall, is continued along it to the middle line 
of the abdomen. 
Above the transverse colon (Fig. 855) the peritoneum can be traced, forming 
the greater and lesser cavities, and their communication through the foramen of 
Winslow can be demonstrated. Commencing in the middle line of the abdomen, 
the membrane may be traced lining its anterior wall, and sending a process back- THE ORGANS OF DIGESTION 
1252 
ward to encircle the obliterated umbilical vein (the round ligament of the liver), 
forming the falciform or longitudinal ligament of the liver. Continuing its course 
Aorta 
Small 
intestine 
Lymphatic 
node 
Vena cava 
inferior 
Ascending 
colon 
Peritoneum 
Mesentery 
Mesocolon 
(imperfect) 
Psoas 
Descending 
colon 
Right 
kidney 
Left kidney 
Fig. 854.-Peritoneal reflection in a transverse section of a lumbar region below the transverse colon. 
Seen from above. Schematic. (Tillaux.) 
to the right, it is reflected over the front of the upper part of the right kidney, 
across the vena cava inferior and aorta, and over the left kidney to the hilum of 
Vessels tn lesser 
omentum 
Lig. teres 
Gs 
Ls 
Foramen oj 
Winslow 
Aorta 
Vena cava 
inferior 
Fig. 855.-Transverse section of peritoneum above the transverse colon. The arrow points to the lesser 
sac and passes through the foramen of Winslow. 
the spleen, forming the anterior layer of the lieno-renal ligament, the posterior 
layer being formed by the termination of the cul-de-sac of the greater cavity THE PERITONEUM 
between the kidney and spleen. From the hilum of the spleen it is reflected to the 
stomach, forming the posterior layer of the gastro-splenic omentum (ligamentum 
1253 
Lig. teres 
Fig. 856.-Horizontal section through the abdomen at the level of the foramen of Winslow. 
(Modified from Godlee.) 
gastrolienale). It covers the posterior surface of the stomach, and from its lesser 
curvature it passes around the portal vein, hepatic artery, and bile-duct, and back 
Lesser omentum. 
ROUND LIGAMENT OF LIVER. 
Hepatic artery, portal 
J vein, and hepatic duct. 
Gastro-splenie 
omentum 
LIENO-RENAL LIGAMENT. 
Abdominal aorta 
Vena cava. 
again to the stomach, as the lesser omentum, and thus it forms the anterior boun- 
dary of the foramen of Winslow. It now covers the front of the stomach, and 
Fig. 857.-Transverse section of peritoneum. 1254 
THE ORGANS OF DIGESTION 
upon reaching the cardiac extremity it passes to the hilum of the spleen, form- 
ing the anterior layer of the gastro-splenic omentum. From the hilum of the 
spleen it can be traced over the surface of this organ, to which it gives a serous 
covering; it is then reflected from the posterior border of the hilum on to the left 
kidney, forming the posterior layer of the lieno-renal ligament. 
Numerous folds, formed by the peritoneum, extend between the various organs or 
connect them to the parietes. These serve to hold the organs in position, and at the 
same time enclose the vessels and nerves proceeding to each part. Some of these 
folds are called ligaments, such as the ligaments of the liver and the false ligaments 
of the bladder. Others, which connect certain parts of the intestine with the 
abdominal wall, constitute the mesenteries; and lastly, those which proceed from 
the stomach to certain viscera in its neighborhood are called omenta. 
Papillary tubercle. 
Fig. 858.-Bursa omentalis, opened from the front by an incision through the gastro-colic omentum. A probe 
passes through the foramen of Winslow and rests on the gastro-pancreatic fold. (Henle.) 
The Ligaments of the Peritoneum.-The ligaments, formed by folds of the peri- 
toneum, include those of the liver, spleen, bladder, and uterus. They will be 
found described with their respective organs. 
The Omenta.-The omenta are: the lesser omentum, the great omentum, and the 
gastro-splenic omentum. 
The Lesser or Gastro-hepatic Omentum (omentum minus') (Figs. 853 and 858) is the 
duplicature which extends between the transverse fissure of the liver and the right 
side of the abdominal portion of the oesophagus, the lesser curvature of the stomach, 
and the upper portion of the superior surface of the duodenum. The portion going 
to the oesophagus and stomach is called the hepato-gastric ligament (ligamentum 
hepatogastricum). The division of the ligament which goes to the oesophagus is 
strong and dense; the division which goes to the lesser curvature of the stomach 
is thin and relaxed. The portion of the lesser omentum which goes to the 
duodenum is continuous with the first-named portion. It is called the hepato- THE PERITONEUM 
1255 
duodenal ligament (ligamentum hepatoduodenale). The right margin of this liga- 
ment is free and concave. The' hepato-colic ligament (ligamentum hepatocoli- 
cum) is not invariably present. It is a fold of the hepato-duodenal ligament and 
HEPATIC 
DUCT 
ROUND 
LIGAMENT 
OMENTAL 
TUBEROSITY 
GASTRIC 
' M PRESSION 
POSTERIOR LAYER 
OF LESSER 
.OMENTUM 
GALL 
BLADDEfl 
OESOPHAGUS 
CYSTIC DUCT* 
DUODENAL 
IMPRESSION' 
FREE EDGE 
OF LESSER 
OMENTUM 
PORTAL 
'vein 
COM MON. 
BILE-DUCT 
HEPATIC 
ARTERY 
□ UOD 
\RIGHT GASTRO- 
EPIPLOIC ARTERY 
PY LOR US 
SUPERIOR PANCREATICO- 
DUODENAL ARTERY 
Fig. 859.-Structure between the layers of the lesser omentum. The liver has been raised up, and the 
anterior layer of the omentum removed. Semidiagrammatic. (Cunningham.) 
PANCREATIC DUCT 
runs from the posterior surface of the gall-bladder to the descending portion of 
the duodenum or possibly to the transverse colon. From the free margin of the 
termination of the hepato-duodenal ligament a fold often passes to the front 
J^ef6 JCubtey' 
RENAL SURFACE 
Pu-ncrea^s 
POUCH OF GREATER SAC 
LIENO-RENAL LIGAMENT 
Lesser Sac 
PHRENIC SURFACE 
GASTRO-SPLENIC 
OMENTUM 
POUCH OF GREATER SAC 
Stomach, 
GASTRIC SURFACE 
Fig. 860.-Horizontal section through the stomach, pancreas, spleen, and the left kidney to show peritoneal 
reflections at the hilum of the spleen. (G. S. H.) 
of the right kidney. It is known as the duodeno-renal ligament (ligamentum 
duodenorenale). The lesser omentum is extremely thin, and consists of two layers 
of peritoneum; that is, the two layers covering respectively the anterior and 1256 
THE ORGANS OF DIGESTION 
posterior surfaces of the stomach. The posterior layer is part of the wall of the 
lesser peritoneal cavity; the anterior layer, of the greater peritoneal cavity. When 
the two layers reach the lesser curvature of the stomach, they join together and 
ascend as the double fold to the transverse fissure of the liver; to the left of this 
fissure the double fold is attached to the fissure of the ductus venosus as far as 
the Diaphragm, where the two layers separate to embrace the end of the oesoph- 
agus. At the right border the lesser omentum is free, and the two layers of 
which it is composed are continuous. The anterior layer, which belongs to the 
greater sac, turns around the hepatic vessels to become continuous with the poste- 
rior layer belonging to the lesser one. They here form a free, rounded margin, 
which contains between its layers the hepatic artery, the common bile-duct, the 
portal vein, lymphatics, and the hepatic plexus of nerves (Fig. 859)-all these struc- 
tures being enclosed in loose areolar tissue, called Glisson's capsule. Between the 
layers where they are attached to the stomach lie the gastric artery and the pyloric 
branch of the hepatic artery, anastomosing with it. From the left side of the 
greater curvature of the stomach a fold passes to the gastric surface of the spleen, 
covers the spleen, and passes from the renal surface of the spleen around the 
left kidney to the Diaphragm.1 The fold passing to the spleen is known as the 
gastro-splenic ligament or the gastro-splenic omentum (lig amentum gastrolienale) 
(Fig. 860). The portion passing to the Diaphragm is known as the spleno- 
phrenic ligament (lig amentum phrenicolienale). The gastric veins or vasa brevia 
pass from the left side of the greater curvature of the stomach toward the 
spleen in the gastro-splenic omentum. 
The Great or Gastro-colic Omentum (omentum majus) (Figs. 853 and 861) is the 
largest peritoneal fold. It consists of four layers of peritoneum, two of which 
descend from the stomach, one from its anterior, the other from its posterior 
surface, and, uniting at its lower border, descend in front of the small intestines, 
sometimes as low down as the pelvis; they then turn upon themselves, and ascend 
again as far as the transverse colon, where they separate and enclose that part 
of the intestine. These separate layers may be easily demonstrated in the young 
subject, but in the adult they are more or less inseparably blended. At the free 
margins the two outer layers and the two inner layers become continuous. The 
left border of the great omentum is continuous with the gastro-splenic omentum; 
its right border extends as far only as the duodenum. The great omentum is 
usually thin, presents a cribriform appearance, and always contains some adipose 
tissue, which in fat subjects accumulates in considerable quantity. Between its 
two anterior layers is the anastomosis between the right and left gastro-epiploic 
arteries. In opening the abdomen the great omentum is rarely found spread out 
evenly over the intestines. It often projects between intestinal coils, or is largely 
gathered in some one region, or is pushed in front of the stomach by distention 
of the colon. 
The lower portion of the lesser sac of the peritoneum continues for a distance 
between the ascending and descending layers of the great omentum (Fig. 853). 
The portion of the lesser peritoneal cavity within the great omentum is more or 
less obliterated in the adult by adhesion between its opposing layers. At birth 
the omentum is very short and barely reaches the umbilicus. In adults its length 
varies greatly. In some individuals it is very short; in others it passes into the 
pelvis. Mr. Lockwood points out that in persons under forty-five years of age 
the omentum can rarely be pulled down below the level of the pubic spine; in 
older persons it generally can. 
Fhe Gastro-splenic Omentum is the fold which connects the margins of the 
hilum of the spleen to the cul-de-sac of the stomach, being continuous by its lower 
1 Spalteholz, Hand Atlas of Human Anatomy. Translated and edited by Prof. Lewellys F. Barker. THE PERITONEUM 
1257 
border with the great omentum. It was described as the gastro-splenic liga- 
ment (Fig. 860). 
The Mesenteries.-The mesenteries are: the mesentery proper, the transverse 
mesocolon, the sigmoid mesocolon, the mesorectum (p. 1259), and the mesentery of 
the vermiform appendix. In addition to these there are sometimes present an 
ascending and a descending mesocolon. 
The Mesentery (me senter ium) (petrov Prepay) (Figs. 853, 862, and 863), so called 
from being connected to the middle of the cylinder of the small intestine, is the 
broad fold of peritoneum which connects the convolutions of the jejunum and 
ileum with the posterior wall of the abdomen. It consists of a layer of connec- 
tive tissue, each side of which is covered with peritoneum. In the connective 
Fig. 861.-The great omentum as seen from the front. (Testut.) 
tissue there are fatty masses. Its root (radix mesenterii), the part connected with 
the vertebral column, is narrow, about six inches in length, and directed obliquely 
from the left side of the second lumbar vertebra to the right sacro-iliac symphysis 
(Fig. 863). Its intestinal border is vastly broader (measures about twenty feet); 
and here its two layers separate so as to enclose the intestine, and form its peri- 
toneal coat. Its breadth, between its vertebral and intestinal border, is about 
eight inches. Its upper border is continuous with the under surface of the trans- 
verse mesocolon; its lower border, with the peritoneum covering the caecum and 1258 
THE ORGANS OF DIGESTION 
ascending colon. The origin of the mesentery above is just beyond the termina- 
tion of the duodenum, and it terminates below in the angle formed by the junction 
of the ileum and the colon. It serves to retain the small intestines in their position, 
and contains between its layers the mesenteric vessels and nerves, the lymphatic 
vessels and mesenteric glands. These glands number from 50 to 150. Occa- 
sionally congenital mesenteric openings exist. In stout individuals the mesentery 
contains much fat. If there is much fat the mesentery is not translucent; if 
there is little fat it is translucent. It may be actually transparent above and 
translucent or opaque below. The thinnest part of the mesentery is above. As 
we descend it becomes thicker, because of the presence of fat, fibrous ligament, 
and muscular tissue.1 
Duodenum 
Mesentery 
(left leaf)' 
Root of mesen-' 
tery 
Ileum- 
Sigmoid flexure- 
Cxcum- 
Fig. 862.-Mesentery. Small intestine pushed to the right and above. (Tillaux.) 
Sigmoid flexure 
In most cases the peritoneum covers only the front and sides of the ascending 
and descending parts of the colon. Sometimes, however, these are surrounded by 
the serous membrane and attached to the posterior abdominal wall by an ascending 
mesocolon (mesocolon ascendens) and a descending mesocolon (mesocolon descendent) 
1 Intestinal Localization. By Geo. H. Monks, Annals of Surgery, October, 1903. THE PERITONEUM 
1259 
respectively. At the place where the transverse colon turns downward to form the 
descending colon, a fold of peritoneum is continued to the under surface of the 
Diaphragm opposite the tenth and eleventh ribs. This is the phreno-colic ligament 
(ligamentum phrenicocolicum); it passes below the spleen, and serves to support 
this organ, and therefore it has received the second name of sustentaculum lienis. 
The Transverse Mesocolon (mesocolon transversum) (Fig. 863) is a broad fold, 
which connects the transverse colon to the posterior wall of the abdomen. It is 
formed by the two ascending or posterior layers of the great omentum, which, after 
Right lateral 
ligament of liver. 
Falciform ligament 
of liver. 
Left lateral 
ligament of liver. 
Peritoneum. 
Extra-peritoneal tissue. 
Vena cava inferior. 
( Diaphragmatic end of 
< gastro-hepatic omentum. 
G astro-phrenic ligament. 
Right phrenic artery. 
(Esophagus. 
Coronary artery.' 
Gastrosplenic omentum. 
Foramen of Winslow. 
Duodenum (1st part). 
Hepatic artery. 
Splenic artery. 
Pancreas. 
Inf. pane.-duo. artery. 
Colica media. ■ 
Superior mesenteric. 
Duodenum (3rd part). 
Aorta. 
Duodenum (2nd part). 
Right and left kidneys. 
Superior mesenteric. 
Aorta. 
Costo-colic ligament. 
Dot between two anterior 
layers of great omentum. 
Transverse meso-colon. 
Bare surface for descend- 
ing colon. 
The two layers of the 
mesentery proper. 
Colica sinistra. 
Colica dextra. 
Vasa intestini. • 
Bare surface for ascend- 
ing colon. 
Sigmoid artery. 
Sup. hcemorrhoidal artery. 
Common iliac artery.' 
.Sigmoid meso-colon. 
Internal iliac artery. 
.Bare surface for caecum. 
■Meso-rectum. 
External iliac artery. 
Bare surface for 2nd part 
of rectum. 
Left lateral false liga- 
ment of bladder. 
Epigastric artery. 
Bladder. 
Fig. 863.-Diagram devised by Dr. DelSpine to show the lines along which the peritoneum leaves the wall 
of the abdomen to invest the viscera. 
separating to surround the transverse colon, join behind it, and are continued 
backward to the spine, where they diverge in front of the duodenum. This fold 
contains between its layers the vessels which supply the transverse colon. 
The Sigmoid Mesocolon (mesocolon sigmoideum) (Fig. 863) is the fold of peri- 
toneum which retains the sigmoid flexure in connection with the left iliac fossa. 
This portion of intestine remains always freely movable. 
The Mesorectum is really only the lower portion of the sigmoid mesocolon. It 
is the name formerly given to the narrow fold which, according to the old defini- 1260 
THE ORGANS OF DIGESTION 
tion of the rectum, connects the upper part of the rectum with the front of the 
sacrum. It contains the superior hemorrhoidal vessels. 
The Mesoappendix or Mesentery of the Vermiform Appendix (mesenterial um pro- 
cessus vermiformis) (Fig.867)is a double fold of peritoneum which usually completely 
surrounds the vermiform appendix. It is usually described as a triangular fold, 
and at a glance it appears so, but Jonnesco points out that it has four borders: a 
superior or mesenteric border; a right or caecal; a left or free, and an inferior 
or appendicular. One of the borders is often extremely short. The upper sur- 
face of the mesoappendix is continuous with the lower surface of the mesentery 
proper and with the left or internal fold of the peritoneum covering the caecum. 
The lower surface of the mesoappendix is continuous with the right or external 
fold of peritoneum covering the caecum. As a rule, the entire appendix is covered 
with peritoneum; sometimes a portion of the base is uncovered, and this portion of 
the diverticulum is then extraperitoneal. The tip is never extraperitoneal. The 
mesoappendix may be attached to the entire length of the appendix, but, as a 
rule, the tip is free. In fact, one-third, one-half, or two-thirds may be free and 
occasionally the mesoappendix is a mere vestige. Between the two peritoneal 
layers of the mesoappendix there is connective tissue, and often fat. In the 
connective tissue are the appendicular blood-vessels, lymph-vessels, and nerves. 
The Appendices Epiploicae are small pouches of the peritoneum filled with fat 
and situated along the colon and upper part of the rectum. They are chiefly 
appended to the transverse colon. 
INFERIOR 
MESENTERIC 
VEIN 
TRANS. MESOCOLON/ 
L . //' 
SUPERIOR 
^DUODENAL 
FOLD 
JEJUNUM 
SUPERIOR 
DUODENAL 
FOLD 
Fiesen^ 
^TER^ 
IN FERIOR 
DUODENAL 
-FOLD 
INFERIOR 
DUODENAL 
FOLD 
ARTERIA 
COLICA 
SINESTRA 
Fig. 864.-Superior and inferior duodenal fossa. (Poirier and Charpy.) 
Retro-peritoneal Fossae.-In certain parts of the abdominal cavity there are 
recesses of peritoneum forming culs-de-sac or pouches, which are of surgical inter- 
est in connection with the possibility of the occurrence of retro-peritoneal hernia. 
One of these, which was previously described, is the lesser sac of the peritoneum 
(Figs. 853 and 855), which may be regarded as a recess of peritoneum through the 
foramen of Winslow, in which a hernia may take place, but there are several 
others, of smaller size, which require mention. 
These recesses of fossae may be divided into three groups, viz.: (1) the duodenal 
fossae; (2) pericaecal fossae; and (3) the intersigmoid fossa. 
1. Duodenal Folds and Fossae.-Moynihan has described no less than nine fossae 
as occurring in the neighborhood of the duodenum. Three of these are fairly 
constant. Five of the fossae are here considered, (a) The inferior duodenal 
fossa or fossa of Treitz (Fig. 864) is the most constant of all the peritoneal fossae 
in this region, being present in from 70 to 75 per cent, of cases. It is situated THE PERITONEUM 
1261 
opposite the third lumbar vertebra on the left side of the ascending portion of the 
duodenum. The opening into the fossa is directed upward, and is bounded by a 
thin, sharp fold of peritoneum with a concave free upper margin. This fold of 
peritoneum is called the inferior duodenal fold (plica duodenomesocolica). The 
tip of the index finger introduced into the fossa under the fold passes some little 
distance up behind the ascending or fourth portion of the duodenum. One margin 
of the fold is attached to the ascending portion of the duodenum; another margin 
is attached to the parietal peritoneum, (ft) The superior duodenal fossa (Fig. 864) 
is the next most constant pouch or recess, being present in from 40 to 50 per cent, 
of cases. It often coexists with the inferior one, and its orifice looks downward, 
in the opposite direction to the preceding fossa. It lies to the left of the ascend- 
ing portion of the duodenum. It is bounded in front by the superior duodenal fold 
(plica duodenajejunalis), which is triangular and has a free semilunar base; to the 
TRANSVERSE 
MESOCO LO N 
JEJUNUM 
RIGHT RETRO- 
DUODENAL 
WALL 
MESENTERY/ 
INFERIOR 
MESENTERIC 
VEIN 
IN FERIOR 
DUODENAL 
ANGLE 
PARIETAL FOLD 
OF DUODENUM 
LEFT COLIC 
ARTERY 
INFERIOR MESEN- 
TERIC ARTERY 
Fig. 865.-Retro-duodenal fossa. (Poirier and Charpy.) 
right it is blended with the peritoneum covering the ascending duodenum, and to 
the left with the peritoneum covering the perirenal tissues. The fossa is bounded 
in front by the superior duodenal fold; behind by the second lumbar vertebra; to 
the right by the duodenum. Its depth is 2 cm., and it terminates in the angle 
formed by the left renal vein crossing the aorta. This fossa is of importance, as 
it is in relation with the inferior mesenteric vein; that is to say, the vein almost 
always corresponds to the line of union of the superior duodenal fold with the 
posterior parietal peritoneum, (c) The duodeno-jejunal fossa or mesocolic fossa 
(recessus duodenojejunalis) is formed where the duodeno-jejunal angle enters the 
root of the transverse mesocolon. There are two forms: (1) a single fossa and (2) 
a double fossa. It can be seen by pulling the jejunum downward and to the right, 
after the transverse colon has been pulled upward. It will appear as an almost 
circular opening, looking downward and to the right, and bounded by two free 
borders or folds of peritoneum, the duodeno-mesocolic ligaments. The opening 
admits the little finger into the fossa to the depth of from 2 to 3 cm. The fossa 1262 
THE ORGANS OF DIGESTION 
is bounded above by the pancreas, to the right by the aorta, and to the left by the 
kidney; beneath is the left renal vein. The fossa exists in from 15 to 20 per 
cent, of cases, and has never yet been found in conjunction with any other form 
of duodenal fossa, (d) Paraduodenal fossa or the fossa of Landzert (recessus duo- 
denojejunalis) is most distinct in the infant, and is to the left of the ascending 
portion of the duodenum. The fold of peritoneum to its outer side and above is 
ANTERIOR 
ILEOCXECAL 
ARTERY 
ANTERIOR ILEO- 
C£CAL FOLD 
MESENTERY 
COLON 
ANTERIOR 
ILEOCECAL 
FOSSA 
INFERIOR 
ILEOCXECAL 
FOLD 
ILEUM 
ZE C U M) 
Fig. 866.-Anterior, sometimes called superior, ileo-csecal fossa. (Poirier and Charpy.) 
produced by the inferior mesenteric vein. Its lower limit is a fold called the 
mesenterico-mesocolic fold, (e) The retroduodenal fossa (Fig. 865) was described 
in 1893 by Jonnesco. It is a peritoneal cul-de-sac, sometimes found behind the 
horizontal and ascending portions of the duodenum. 
2. Pericsecal Folds and Fossae.-There are at least three pouches or recesses to be 
found in the neighborhood of the caecum, which are termed pericsecal fossae. (1) 
ILEO-APPEN DICULAR 
FOSSA 
ILEUM 
ILEO-APPEN- 
DICULAR FOLD 
MESENTERY 
APPENDICULAR 
ARTERY 
I LEO-APRENDICULAR 
ARTERY 
MESO-APRENDIX 
C ZEZ C U M 
Fig. 867.-Ileo-appendicular or inferior ileo-crecal fossa. The caecum and ascending colon have been 
drawn outward and downward, the ileum upward and backward, and the appendix downward. (Poirier 
and Charpy.) 
The ileo-colic fossa or superior ileo-csecal (recessus ileocaecalis superior) (Fig. 866) 
is formed by a fold of peritoneum, the ileo-colic fold, arching over a branch of 
the ileo-colic artery, which supplies the ileo-colic junction, and appears to be the 
direct continuation of the artery. The fossa is a narrow chink situated between 
the ileo-colic fold in front, and the mesentery of the small intestine, the ileum, THE PERITONEUM 
1263 
and a small portion of the caecum behind. (2) The ileo-caecal, inferior ileo-caecal 
or ileo-appendicular fossa (recessus ileocaecalis inferior) (Fig. 867) is situated behind 
the angle of junction of the ileum and caecum. It is formed by a fold of peritoneum, 
the ileo-caecal fold (plica ileocaecalis), which Treves called the "bloodless fold." 
Tuffier denies its non-vascularity, and Lockwood and Rolleston state that it con- 
tains fat, muscular fibres, and arteries and veins derived from the appendicular ves- 
sels and the anterior and posterior ileo-caecal vessels.1 The upper border of the fold 
is attached to the ileum, opposite its mesenteric attachment, and the lower border, 
passing over the ileo-caecal junction, joins the mesentery of the appendix, and 
sometimes the appendix itself; hence this fold is sometimes called the ileo-appen- 
dicular fold. Between the ileo-caecal fold and the mesentery of the vermiform 
appendix is the ileo-caecal fossa. It is bounded above by the posterior surface of 
the ileum and the mesentery; in front and below by the ileo-caecal fold, and behind 
by the upper part of the mesentery of the appendix. (3) The retro-caecal or retro-colic 
ILEO-APPEN DICULAR 
FOLD 
ILEUM 
I LEO-APPEN DICULAR 
"fossa 
-MESO-APPENDIX 
SUPERIOR 
CAECAL FOLD 
INFERIOR 
CZECAL FOLD 
RETRO-C/ECAL 
FOSSA 
Fig. 868.-The retro-caecal fossa. The ileum and caecum are drawn backward and upward. (Souligoux.) 
fossae (recessus retrocaecalis) (Fig. 868) are situated behind the caecum and ascend- 
ing colon. There may be no fossa present. There may be one fossa; there are 
usually two (external and internal retrocolic fossae); occasionally there are more 
than two.2 The fossae are brought into view by raising the caecum. According to 
Berry, one or other of the fossa is present in 30 per cent, of cases. Treves thinks 
the retrocolic fossae are extremely rare. There may be one fossa (20 per cent, of 
cases) or two fossae (10 per cent, of cases). If there is but one fossa it is the 
internal that exists three times as often as the external. The retro-colic space, 
if present, varies much in size and extent. In some cases it is sufficiently large 
to admit the index finger and extends upward behind the ascending colon in 
the direction of the kidney; in others it is merely a shallow depression. The 
external retro-colic fossa is bounded and formed by two folds: one, the external 
parieto-colic fold or the superior caecal fold, which is the outer layer of the ascend- 
ing mesocolon, and is attached by one edge to the abdominal wall from the 
lower border of the kidney to the iliac fossa and by the other to the postero- 
' The Caecal Folds and Fossae. By Richard J. A. Berry. 2 Ibid. 1264 
THE ORGANS OF DIGESTION 
external aspect of the colon; and the other, the internal parieto-colic fold or inferior 
caecal fold, which is the inner layer of the ascending mesocolon. The internal 
retrocolic fossa is bounded externally by the internal parieto-colic fold, and is 
bounded internally by the mesenterico-parietal fold, which is the insertion of the 
mesentery into the iliac fossa. 
3. The Intersigmoid Fossa {recessus intersigmoideus).-The intersigmoid fossa 
is constant in the foetus and common during infancy, but disappears in a large 
percentage of cases as age advances. Upon drawing the sigmoid flexure upward, 
the left surface of the sigmoid mesocolon is exposed, and on it will be seen a 
funnel-shaped recess of the peritoneum, lying on the external iliac vessels, in the 
interspace between the Psoas and Iliacus muscles. This is the orifice leading to 
the fossa intersigmoidea, which lies behind the sigmoid mesocolon, and in front of 
the parietal peritoneum. This fossa is produced by the incomplete fusion in the 
foetus of the descending mesocolon with the parietal peritoneum. The fossa varies 
in size; in some instances it is a mere dimple, whereas in others it will admit the 
whole of the index finger. 
Any of these fossae may be the site of a retro-peritoneal hernia. The pericaecal 
fossae are of especial interest, because hernia of the vermiform appendix frequently 
takes place into one of them, and may there become strangulated. The presence 
of these pouches also explains the course which pus has been known to take in 
cases of perforation of the appendix, where it travels upward behind the ascending 
colon as far as the Diaphragm.1 
Surgical Anatomy.-Study of the lymphatics of the peritoneum by Byron Robinson and 
others shows that absorption takes place most rapidly from the region of the Diaphragm, less 
rapidly but still very actively from the region of the small intestine, slowly from the pelvic 
region. Clinically we know that pelvic peritonitis is not nearly so dangerous as peritonitis 
in the small intestine or Diaphragm areas, and that peritonitis in the region of the Diaphragm 
is the most fatal form of the infection. After abdominal operations in infected cases, it is 
well to elevate the head of the bed {Fowler's position), so as to obtain the aid of gravity in 
draining septic fluids away from the dangerous region and toward the safer region.2 In areas 
in which absorption is rapid, protective exudation is not apt to form. In areas in which 
absorption is slow, inflammatory exudation is apt to circumscribe the area and prevent diffu- 
sion. After an operation in a non-infected case, if salt solution has been left in the abdominal 
cavity because of shock or hemorrhage, raising the foot of the bed will aid rapid absorption 
of the fluid by favoring the natural current toward the Diaphragm and hurrying the fluid to a. 
region in which absorption is rapid. 
The great omentum stores up fat, and, being movable, it is able to pass to different parts 
of the peritoneal cavity. Dr. Byron Robinson, in his work on the Peritoneum, describes its 
functions as follows: ''The omentum is the great protector against peritoneal infectious 
invasions. It builds barriers of exudates to check infection. It is like a man-of-war, 
ready at a moment's notice to move to invaded parts. It circumscribes abscesses; it repairs 
visceral wounds, and prevents adhesions of mobile viscera to the anterior abdominal wall. 
It resists infectious invasions by typical peritoneal exudates, and not by succumbing to absorbed 
sepsis. It is a director of peritoneal fluids, a peritoneal drain." 
In abdominal wounds the omentum often protrudes: This structure frequently constitutes 
or is part of a hernia, and is almost invariably present in umbilical hernia. As a result of 
inflammation, it may become adherent to adjacent structures. Adhesions may be of service by 
matting together the intestines and circumscribing infections. They may be harmful by 
constricting the bowels and producing obstruction. A portion of the omentum may become 
adherent to some other part and form a band, and under this band the gut may be caught and 
strangulated. Omentum may adhere to and plug a perforation in a hollow viscus, and the sur- 
geon may utilize it for the same purpose, or to cover a raw surface or overlie a suture line. The 
omentum may be in the surgeon's way while operating. If it is, the patient is placed in the 
Trendelenburg position (pelvis elevated). 
Any tear or opening found by the surgeon in the great omentum must be closed with sutures, 
because of the danger that intestine might enter and be caught in such an opening. A tumor 
cut off from its proper blood-supply, for instance, an ovarian cyst with a twisted pedicle, may 
continue to receive nourishment from adherent omentum, and gangrene may thus be prevented. 
1 On the anatomy of these fossae, see the Arris and Gale Lectures by Moynihan, 1899. 
2 George R. Fowler, in Medical Record, April 14, 1900. THE PERITONEUM 
1265 
The lax character and shifting tendency of the subserous tissue explains the occurrence of 
ptosis of the abdominal viscera and kidneys. 
The vast number of nerves in the peritoneum accounts for the profound shock which follows 
a wound, attends an intraperitoneal calamity, or which develops from infection. An infective 
process of any portion of the peritoneum produces pain and reflex symptoms (vomiting, 
abdominal rigidity, intestinal paresis, etc.). 
The parietal peritoneum is very sensitive to pain, but not to touch; hence, after injecting a 
local anaesthetic and opening the abdomen, a fairly satisfactory exploration can be made with 
the finger. 
The intestine, the mesentery, the stomach, the anterior margin of the liver, and the gall-bladder 
are insensitive, and may be cut or even burned without pain.1 
Viscera which obtain their innervation purely from visceral nerves are insensitive; those which 
receive branches from somatic nerves are sensitive (Lennander). 
The oblique origin of the mesentery causes this structure to form a sort of shelf. A hemor- 
rhage or extravasation into the abdomen, to the right of the mesentery, tends to flow into th'* 
right iliac fossa; one occurring on the left side flows into the pelvis. Monks points out that in 
flushing the abdominal cavity the tube should not be aimlessly introduced, but should utilize 
the mesentery on each side of an intestinal loop, to '' conduct the tip of the irrigating tube to the 
bottom of the two fossae."2 Monks also shows how the mesentery can be utilized to determine 
the direction of an intestinal loop: 
"Now, let us suppose that the surgeon has between his fingers a loop of bowel, and wishes 
to determine its direction. He knows that one side of the loop is the left side of the intestine, 
and that the corresponding side of the mesentery, if closely followed down to the mesenteric 
root, will conduct him into the left fossa; he also knows that the other side of the bowel is its 
right side, and that the mesentery on that side will conduct him into the right fossa. Now7, 
Fig. 869.-A loop of intestine, the middle of which is exactly three feet from the end of the duodenum. The 
gut is of large size. The mesenteric loops are primary, and the vasa recta large, long, and regular in distribu- 
tion. The translucent spaces (lunettes) between the vessels are extensive. Below, the mesentery is streaked 
with fat. The veins, which had a distribution similar to the arteries, are for simplicity omitted from this and 
from the subsequent drawings. (The subject from which the specimen was taken was a male aged forty years, 
with rather less than the usual amount of fat. The entire length of the intestine was twenty-three feet. 
(Monks.) 
if his finger goes into the great fossa on the left side of the abdomen, after having closely fol- 
lowed the mesentery down to its root and arranged his loop to be parallel with that root, he then 
knows that the left and right sides of the intestine face to the left and right sides of the abdomen 
respectively, and that the end of the loop which points downward is the end nearest the ileo- 
csecal valve. He can determine the direction of the gut in a similar way in case his finger enters 
the right fossa. All this would seem very simple were it not for the twists in mesentery and 
intestine, which tend to mislead one. A little practice will usually enable one to recognize a twist 
in the mesentery. This should be untwisted by rotation of the gut, after which the direction is 
determined by another palpation of the mesenteric root."3 
1 Dr. K. E. L. Lennander, in Mittheilungen aus dem Grenzgebrieten der Medecin und Chirurgie, 1902, Band x„, 
Heft 1,2. 
2 Intestinal Localization, by George H. Monks, Annals of Surgery, October 1903. 
3 Annals of Surgery, October, 1903. 1266 
THE ORGANS OF DIGESTION 
The studies made of the arrangement and variations of the loops of the mesenteric vessels by 
Dr. Thomas Dwight1 have been utilized and expanded by Dr. George H. Monks in laying down 
Fig. 870.-A loop of intestine at six feet. As compared with Fig. 869 the gut is somewhat smaller. The 
vascularity of the intestine and mesentery is less. Secondary loops are a prominent feature. The vasa recta 
are smaller. The lunettes are also present, but are not so large as in Fig. 869. (The subject was a male aged 
about thirty-five years, with an average amount of fat. The entire length of the intestine was twenty feet. 
(Monks.) 
rules for the determination of the exact portion of small intestine which may be in the surgeon's 
hand.2 His views are as follows: 
' ' General Vascularity of the Mesentery near the Bowel.-Opposite the u pper part of the bowel the 
mesenteric vessels are distinctly larger than opposite any other part of it. These vessels grow 
Fig. 871.-A loop of intestine at nine feet. The secondary loops are large; the vasa recta are somewhat 
irregular and show branches. No lunettes are present, and the mesentery is streaked with fat, and is, therefore, 
somewhat opaque. (The specimen was taken from the same subject which furnished Fig. 869. (Monks.) 
smaller and smaller as we pass downward until the lower third of the gut is reached, where they 
remain about the same size as far as the ileo-caecal valve. The arrangement of the mesenteric 
1 Reports of the Meeting of American Anatomists, 1897. 2 Annals of Surgery, 1903. THE PERITONEUM 
1267 
vessels has some features which intimately concern the subject in hand, and which I shall describe 
with some detail. Diagrammatically speaking, the main branches of the superior mesenteric 
artery unite with each other by means of loops, which are called for convenience 'primary loops;' 
in some parts of the tube, 'secondary loops,' and even, occasionally, 'tertiary loops' are super- 
Fig. 872. - A loop of intestine at twelve feet. The vessels are smaller. The primary loops are lost in the fat, 
but secondary and even tertiary loops are visible. The vasa recta are shorter, more irregular, and branching. 
(The specimen came from the same subject which furnished Figs. 869 and 871.) (Monks.) 
imposed upon these. From these loops little straight vessels-the vasa recta already referred to 
-run to the bowel, upon which they ramify, alternating, as a rule, as to the side of the intestine 
which they supply. The mesenteric veins are arranged in a manner somewhat similar to the 
arteries. 
Fig. 873. -A loop of intestine at seventeen feet. The mesentery is opaque, and small tabs of fat begin to 
appear along the mesenteric border of the gut. The vessels are represented by a somewhat complicated net- 
work, and are seen with difficulty in the thick fat of the mesentery. (The specimen came from the subject 
which furnished Figs. 869, 871, and 872.) (Monks.) 
" The Loops of the Mesenteric Vessels (Figs. 869, 870, 871, 872, and 873).-Opposite the upper 
part of the bowel there are only primary loops. Occasionally a secondary loop appears, but it 
is small and insignificant as compared with the primary loops, which are large and quite regular. 
As we proceed down the bowel secondary loops become more numerous, larger, and approach 1268 
THE ORGANS OF DIGESTION 
nearer to the bowel than the primary loops in the upper part. As a rule, secondary loops 
become a prominent feature at about the fourth foot. As we continue farther downward, the 
secondary loops (and, possibly, tertiary loops) become still more numerous and the primary 
loops smaller, the loops all the time getting nearer and nearer to the gut. Opposite the lower 
part of the gut the loops generally lose their characteristic appearance, and are represented by 
a complicated network. 
" The Vasa Recta.-Opposite the upper part of the intestine the vasa recta are from three to 
five centimetres long, when the loop of small intestine to which they run is lifted up so as to 
put them gently on the stretch. They are straight, large, and regular, and rarely give off branches 
in the mesentery. In the lower third they are very short, being generally less than one centimetre 
in length. Here they are less straight, smaller, less regular, and have frequent branches in the 
mesentery." 
Fig. 874.-A loop of intestine at twenty feet. The gut appears to be thick and large. The mesentery is 
quite fat and opaque, and large and numerous fat-tabs are present. The vessels, which are complicated, are 
seen with difficulty, and are represented by mere grooves in the fat. (The subject was a stout woman, and the 
entire length of the gut was twenty-one feet.) (Monks.) 
The translucency of the mesentery varies greatly; in some parts it may be almost transparent, 
in others almost or quite opaque. Its thinnest part is above. It is thickened below by fat, fibrous 
tissue, and muscular tissue. In very fat subjects it may be impossible to see the vessels (Monks). 
According to Monks, if a loop is raised and looked at against the light close to the gut "little 
transparent spaces" are seen between the vasa recta, and even in the thickest mesentery; some 
of these " lunettes" exist along the upper portion of the intestine. As we descend in our exam- 
ination, they grow smaller and become fatty, and disappear about the eighth foot of the intes- 
tine.1 The same author shows that the mesentery of the lower third of the intestine, except in 
the thinnest individuals, contains little collections of fat on the border of the mesentery, which 
project toward the bowel and may even extend upon it. 
THE STOMACH (VENTRICULUS) (Figs. 861, 875, 876, 878, 879). 
The stomach is the principal organ of digestion. It is the most dilated part of 
the alimentary canal, and is situated between the termination of the oesophagus 
(cardia) and the commencement of the small intestine. Its form varies because 
of varied conditions, but, as a rule, it is somewhat pyriform. It is placed, in 
part, immediately behind the anterior wall of the abdomen and beneath the 
Diaphragm. Viewing the stomach from in front it appears that the right margin 
of the oesophagus is continued downward as the upper two-thirds of the lesser 
curvature of the stomach, the remaining third of this border bending sharply 
' Annals of Surgery, October, 1903. THH STOMACH 
1269 
backward and to the right, to complete the smaller curvature (Fig. 875). The 
greater curvature begins at the left border of the termination of the oesophagus in 
a somewhat acute angle; it then passes upward and to the left to the under surface 
of the Diaphragm, with which it lies in contact for some distance, and then sweeps 
downward with a convexity to the left, and, continued across the middle line of the 
body, finally turns upward and backward, to terminate at the commencement of 
the small intestine. It will thus be seen that the stomach may be divided into a 
fundus (fundus ventriculi) and a middle portion or body (corpus ventriculi). The 
portion of the body adjacent to the cardia being known as the cardiac portion (pars 
cardiaca), the long axis of which is directed downward with a slight inclination 
forward and to the right; and the portion adjacent to the pylorus being known 
as the pyloric portion (pars pylorica), the long axis of which is horizontal with 
an inclination backward. Of the two openings, the cardiac orifice, by which it 
communicates with the oesophagus, is situated slightly to the left of the middle 
line of the body to the right of the fundus, or dilated upper extremity of the 
stomach, and is directed downward; the other, 
the pyloric orifice, by which it communicates 
with the small intestine, is on a lower plane, 
close to the right of the mid-line, and looks 
directly backward. 
Relations of the Stomach.-The stomach 
lies in a space or chamber called the stomach 
chamber (Fig. 861). When distended the viscus 
completely fills the space. When the stomach 
is empty it lies upon the floor of the chamber, 
and the portion it has vacated is occupied by 
the transverse colon, which ascends in front of 
the stomach and finally gets above it. The 
anterior wall of the stomach chamber is formed 
by the anterior abdominal wall. The roof is formed by the under surface of the 
Diaphragm and the under surface of the left lobe of the liver. The floor is formed 
by the left suprarenal capsule and the summit of the left kidney, the gastric face 
of the spleen, the upper surface of the pancreas, the transverse mesocolon, and 
the colon.1 
Surfaces.-The stomach has two surfaces, called anterior and posterior surfaces, 
and two borders, termed the greater and lesser curvatures. 
In regard to the so-called anterior and posterior surfaces of the stomach, it 
must be borne in mind that these names are not strictly correct, as the anterior 
surface has a certain amount of inclination upward and the posterior downward. 
The Anterior, Upper or Parietal Surface (paries anterior).-The anterior surface 
is directed forward and to the right side. It has a somewhat flattened appearance 
when the stomach is empty, but when it is full the surface becomes convex. It is 
in relation with the Diaphragm; the thoracic wall formed by the anterior parts of 
the seventh, eighth, and ninth ribs of the left side; the left lobe of the liver; and 
the anterior abdominal wall. Between the part covered by the liver and that 
covered by the left ribs there is a triangular segment of the anterior wall of the 
stomach, which is in contact with the abdominal wall and is the only part of the 
stomach which is visible when the abdominal wall is removed and the viscera 
allowed to remain in situ. Its area is about 40 sq. cm., and it is of great impor- 
tance to the surgeon, as the stomach can readily be reached in this situation. 
Occasionally the transverse colon may be found lying in front of the lower part 
of the anterior surface of the stomach. The whole of this surface of the stomach 
is covered by peritoneum. 
Fundus 
Cardiac orifice 
Lesser curvature 
Pylorus 
/ Greater 
curvatur 
Antrum 
pylori 
Fig. 875.-Diagrammatic outline of the 
stomach. 
1 Prof. Birmingham in Prof. Cunningham's Text-book of Anatomy. THE ORGANS OF DIGESTION 
1270 
The Posterior, Lower or Visceral Surface (paries posterior).-The posterior sur- 
face of the stomach is directed backward and to the left. It is in relation with 
the Diaphragm, the gastric surface of the spleen, the left suprarenal capsule, the 
upper part of the left kidney, the anterior surface of the pancreas, the splenic 
flexure of the colon, and the ascending layer of the transverse mesocolon. These 
structures form a shallow concavity or bed, on which this surface of the stomach 
rests. The transverse mesocolon intervenes between the stomach and the duodeno- 
jejunal junction and commencement of the ileum. Its greater curvature is in 
relation with the transverse colon and has attached to it the anterior two layers 
of the great omentum. Almost the whole of this surface is covered with peri- 
toneum, but behind the cardiac orifice there is a small portion of the stomach 
which is uncovered by peritoneum and is in contact with the Diaphragm and fre- 
quently with the upper portion of the left suprarenal capsule. 
The Lesser Curvature (curvatura ventriculi minor).-The lesser curvature of the 
stomach extends between the cardiac and pyloric orifices along the right border 
of the organ. It descends in front of the left crus of the Diaphragm, along the left 
side of the eleventh and twelfth dorsal vertebrae, and then turning to the right it 
crosses the first lumbar vertebra and ascends to the pylorus. It gives attachment 
to the two layers of the gastro-hepatic omentum, between which blood-vessels and 
lymphatics pass to reach the organ. 
The Greater Curvature (curvatura ventriculi major).-The greater curvature of 
the stomach is directed to the left, and is four or five times as long as the lesser 
curvature. Starting from the cardiac orifice, it forms an arch to the left with its 
convexity upward, the highest point of which is on a level with the costal cartilage 
of the sixth rib of the left side. It then passes nearly straight downward, with a 
slight convexity to the left, as low as the costal cartilage of the ninth rib, and then 
turns to the right to end at the pylorus. As it crosses the median line the lowest 
edge of the greater curvature is about two fingers' breadth above the umbilicus. 
The lower part of the greater curvature gives attachment to the two anterior 
layers of the great omentum, between which layers vessels and lymphatics pass 
to the organ. 
The Cardia (Fig. 876).-The cardia is the point at which the oesophagus enters 
the stomach wall. The opening is called the cardiac orifice or the oesophageal 
opening. At the cardia the circular muscular fibres constitute a sphincter. 
The Cardiac Orifice (Fig. 876).-The cardiac orifice is the opening by which the 
oesophagus communicates with the stomach. It is therefore sometimes termed 
the oesophageal opening. It is the most fixed part of the stomach, and is situated 
about two inches below the highest part of the fundus on a level with the body 
of the tenth or eleventh dorsal vertebra to the left and a little in front of the aorta. 
This would correspond on the anterior surface of the body to the articulation of 
the seventh left costal cartilage to the sternum. It is placed far off from the surface 
and is at least four inches back of the seventh left chondro-sternal articulation. 
The Pylorus (Fig. 876).-The pylorus is the point at which the stomach passes 
into the duodenum. The opening of communication is called the pyloric orifice. 
At the pylorus the muscular fibres constitute a sphincter. 
The Pyloric Orifice (Fig. 876).-The pyloric orifice communicates with the duo- 
denum, the aperture being guarded by a valve (Fig. 877). Its position varies with 
the movements of the stomach. When the stomach is empty the pylorus is situ- 
ated just to the right of the median line of the body, on a level with the upper 
border of the first lumbar vertebra. On the anterior surface of the body its posi- 
tion would be indicated by a point one inch below the tip of the ensiform cartilage 
and a little to the right. As the stomach becomes distended the pylorus moves to 
the right, and in a fully distended stomach may be situated two or three inches 
to the right of the median line. The direction of the pylorus is upward and to THE STOMACH 
1271 
the right, which position prevents "the weight of the gastric contents bearing 
directly on the sphincter apparatus."1 The pylorus is on a somewhat higher level 
than the lowest point of the stomach. Near the pylorus the stomach frequently 
exhibits a slight dilatation, which is named the antrum of the pylorus (antrum 
pyloricum). The pylorus is indicated by a constriction, the direction of which 
is circular. The pylorus lies upon the neck of the pancreas behind. Above it 
and in front of it is the liver. 
The size of the stomach varies considerably in different subjects. When mod- 
erately distended its greatest length, from the top of the fundus to the lowest part 
of the greater curvature, is from ten to twelve inches and its diameter at the 
widest part from four to five inches. The distance between the two orifices is three 
to six inches, and the measurement from the anterior to the posterior wall three 
and a half inches. Its weight, according to Ciendinning, is about four ounces and 
a half, and its capacity in the adult male is five to eight pints. The stomach of a 
newborn child holds about one ounce. 
Fig. 876.-The mucous membrane of the stomach and duodenum with the bile-ducts. 
Alterations in Position.-There is no organ in the body the position and connections of which 
present such frequent alterations as the stomach. When empty, it lies at the back part of the 
abdomen, some distance from the surface, and is in the left hypochondriac region and the left 
portion of the epigastric region. Its fundus is directed upward and backward toward the Dia- 
phragm. The long axis of the viscus is nearly horizontal. Its pyloric end is directed upward 
and backward, is situated close to or very slightly to the right of the middle line, covered in front 
bv the left lobe of the liver, and being on a level with the first lumbar vertebra. When empty, 
the stomach assumes a more or less cylindrical form, especially noticeable at its pyloric end. The 
entire viscus is small and contracted, and the pyloric region resembles the intestine. When the 
stomach is distended, its surfaces, which are flattened when the organ is empty, become convex 
and the shape becomes pyriform. The viscus becomes very oblique and approaches the vertical, 
1 W. J. Mayo, Medical Record, June 11, 1904. 1272 
THE ORGANS OF DIGESTION 
its long axis being downward, forward, and to the right. The greater curvature is elevated and 
carried forward, so that the anterior surface is turned more or less upward and the posterior 
surface downward, and the stomach is brought well against the anterior wall of the abdomen. Its 
fundus expands and rises considerably above the level of the cardiac orifice; in doing this the 
Diaphragm is forced upward, contracting the cavity of the chest; hence the dyspnoea complained 
of, from inspiration being impeded. The apex of the heart is also tilted upward; hence the 
oppression in this region and the palpitation experienced in extreme distention of the stomach. 
The left lobe of the liver is pushed to the right side. When the stomach becomes distended 
the change in the position of the pylorus is very considerable; it is shifted to the right, some 
two or three inches from the median line, and lies under cover of the liver, near the neck of the 
gall-bladder. In consequence of the distention of the stomach the lesser cul-de-sac bulges over 
the pylorus, concealing it from view, and causing it to undergo a rotation, so that its orifice is 
directed backward. When the stomach is greatly distended its lower border may enter the 
umbilical and the left lumbar regions. During inspiration the stomach is displaced downward 
by the descent of the Diaphragm, and it is elevated by the pressure of the abdominal muscles dur- 
ing expiration. Pressure from without, as froip tight lacing, pushes the stomach down toward the 
pelvis. In fact, in the female, because of tight lacing, the stomach may be to the left side of the 
vertebral column and nearly vertical in direction, the lower portion being sharply angled upward 
toward the pylorus, which lies underneath the liver. Besides the angulation, the lower end, the 
stomach may have a median constriction, and there may even be an hour-glass stomach. The 
descent of the stomach from tight lacing may cause the pancreas to become nearly vertical. In 
disease the position and connection of the stomach may be greatly changed, from the accumula- 
tion of fluid in the chest or abdomen, or from alteration in size of any of the surrounding viscera. 
Variations according to Age.-In an early period of development the stomach is vertical, and in 
the newborn child it is more vertical than later on in life, as owing to the large size of the liver 
it is more pushed over to the left side of the abdomen, and the whole of the anterior surface is 
covered by the left lobe of this organ. 
On looking into the pyloric end of the stomach, the mucous membrane is found 
projecting inward in the form of a circular fold, the pyloric valve (Fig. 877), leaving 
a narrow circular aperture, about half an inch in 
diameter, by which the stomach communicates with 
the duodenum. 
The Pyloric Valve {valvula pylori) (Fig. 877).-The* 
pyloric valve is formed by a reduplication of the mucous 
membrane of the stomach,containing numerous circular 
fibres, which are aggregated into a thick circular ring, 
the pyloric sphincter (m. sphincter pylori)-, the longitu- 
dinal fibres and serous membrane being continued 
over the fold without assisting in its formation(Fig.877). 
The pylorus is normally kept closed by the action of 
this aggregation of circular fibres which constitutes the 
Sphincter muscle. During the early stage of digestion 
it remains closed, but after a time opens now and then. The opening becomes 
more frequent and the period of patency is prolonged as digestion advances. 
The diameter of the pylorus is uncertain, ft is usually said to be half an inch. 
But it is closed when the pylorus .is at rest, and it can certainly dilate even in 
a child to at least an inch and let bodies of this size pass through. 
The Peritoneum.-The great omentum comes off from the greater curvature of 
the stomach and passes to the transverse colon. The lesser omentum comes off 
from the lesser curvature and passes to the liver. The gastro-splenic ligament or 
omentum passes from the under surface of the stomach just below the greater 
curvature to the spleen. A fold of peritoneum passes up from the stomach along 
the left side of the oesophagus to the Diaphragm. This is the gastro-phrenic 
ligament. 
Supports of the Stomach.-The stomach lies on the bed of the stomach cham- 
ber, which was described on p. 1269. The great omentum gives no support to 
the stomach, neither does the gastro-splenic ligament, because of the movability 
of the spleen. The lesser omentum does give support to the stomach and so do 
Fig. 877.-Diagrammatic view 
of the coats of the stomach, duo- 
denum, and pylorus. The ridge is 
the pyloric valve. (Allan Thom- 
son.) THE STOMACH 
1273 
the gastro-phrenic ligament and the hepato-duodenal ligament. The two chief 
points of support are the attachment of the oesophagus to the Diaphragm and 
the fixation of the duodenum to the front of the vertebral column. 
Structure.-The wall of the stomach consists of four coats: serous, muscular, 
areolar, and mucous, together with vessels and nerves. 
The Peritoneal or Serous Coat (tunica serosa).-The peritoneal or serous coat 
covers the entire surface of the organ, excepting along the greater and lesser 
curvatures, at the points of attachment of the greater and lesser omenta; at 
each curvature the two layers of peritoneum leave a small triangular space, to 
which the peritoneum is not attached, although it is attached in front of it and 
back of it. Along these spaces the nutrient vessels and nerves pass. On the 
posterior surface of the stomach, close to the cardiac orifice and below and to 
the left of it, there is a smaller triangular area uncovered by peritoneum, where 
the organ is in contact with the under surface of the Diaphragm, and it may be 
LONGITUDINAL 
r i;b r es 
PYLORIC 
LIGAMENT 
CIRCULAR 
FIBRES 
(□Wp^ 
Fig. 878.-The superficial muscular layer of the stomach, viewed from above and in front. (Spalteholz.) 
with the left suprarenal body and the summit of the left kidney. When the 
stomach is moderately distended this uncovered area measures about one and a 
half inches from above downward, and about two inches from before backward. 
At the left angle of this uncovered area the insertion of the great omentum 
begins. At the right angle the gastric artery reaches the stomach. 
The Muscular Coat (tunica muscularis) (Figs. 878 and 879).-The muscular coat 
is situated immediately beneath the serous covering, to which it is closely connected. 
It consists of three sets of fibres-longitudinal, circular, and oblique. 
The Longitudinal Fibres (stratum longitudinals) are most superficial; they are 
continuous with the longitudinal fibres of the oesophagus, radiating in a stellate 1274 
THE ORGANS OF DIGESTION 
manner from the cardiac orifice. They are most distinct along the curvatures, 
especially the lesser, but are very thinly distributed over the surfaces. At the 
pyloric end they are more thickly distributed, and continuous with the longitudinal 
fibres of the small intestine. The bundles of longitudinal muscle-fibre on the upper 
and lower surfaces of the pylorus are particularly firm and distinct, and are called 
the pyloric ligaments (ligamenta pylori). 
The Circular Fibres (stratum circulare) form a uniform layer over the whole 
extent of the stomach, except the fundus, beneath the longitudinal fibres. At the 
pylorus they are most abundant, and are aggregated into a circular ring or sphinc- 
ter (m. sphincter pylori), which projects into the cavity, and forms, with the fold 
of mucous membrane covering its surface, the pyloric valve (valvula pylori) (Fig. 
<S77). They are continuous with the circular fibres of the oesophagus. 
PYLORIC 
'LIGAMENT 
Fig. 879.-The middle and deep muscular layer of the stomach, viewed from above and in front. (Spalteholz.) 
The Oblique Fibres (fibrae obliquae) arise at the left side of the cardia from the 
circular fibres of the oesophagus. The fibres pass down in the anterior and pos- 
terior walls. Those of the anterior wall are parallel to the lesser curvature and 
almost reach the pylorus. Those of the posterior wall are more nearly transverse 
to the long axis of the stomach (Spalteholz). These fibres gradually assume the 
direction of the circular fibres and terminate in them. The layer of oblique fibres 
is beneath the circular layer. Certain oblique muscular fibres encircle the fundus 
of the stomach in a series of rings. 
The Areolar or Submucous Coat (tela submucosa).-The areolar or submucous 
coat consists of loose, filamentous, areolar tissue, connecting the mucous and 
muscular layers. It supports the blood-vessels previous to their distribution to 
the mucous membrane; hence it is sometimes called the vascular coat. THE STOMACH 
The Mucous Membrane (tunica mucosa) (Figs. 880, 881, and 882).-The 
mucous membrane is thick; its surface smooth, soft, and velvety. In the fresh 
state it is of a pinkish tinge at the pyloric end, and of a red or reddish-brown 
1275 
Fig. 880.-Mucous membrane of the stomach, from the pars pylorica, viewed from the surface. X 5. (Spalteholz.) 
Gastric Areas. 
Rugae. 
color over the rest of the surface. In in- 
fancy it is of a brighter hue, the vascular 
redness being more marked. It is thin at 
the cardiac extremity, but thicker toward 
the pylorus. During the contracted state 
of the organ it is thrown into numerous 
plaits or rugae (plicae mucosae) (Figs. 880 
and 882 A), which for the most part have a 
longitudinal direction, and are most marked 
toward the lesser end of the stomach and 
along the greater curvature, and which 
contain also submucous tissue. These 
folds are entirely obliterated when the 
organ becomes distended. A constant fold 
exists at the pylorus (Fig. 877). It is called 
the pyloric valve, and is produced by the 
presence beneath it of the Sphincter muscle. 
Besides the large folds or rugae and the 
pyloric valve, there are numerous small 
elevations of mucous membrane known as 
gastric areas (areae gastricae), which are 
partly separated from each other by furrows 
and which vary greatly in shape (Fig. 880). 
According to Spalteholz, each one of these 
elevations has an area of several square 
millimetres. 
Ridges between the alveoli. 
Fig. 881.-Mucous membrane of the stomach, 
from the pars pylorica, viewed from the surface. XI6. 
(Spalteholz.) 
Gastric alveoli. 1276 
THE ORGANS OF DIGESTION 
Structure of the Mucous Membrane.-When examined with a lens the 
inner surface of the mucous membrane presents a peculiar honeycomb appear- 
RUG/E 
MAMMILL/E 
A 
MOUTHS OF GASTRIC 
GLANDS, WITH GLAND 
TUBES AT BOTTOM 
DEPRESSION BETWEEN 
TWO MAMMILLAE 
MOUTH OF 
GASTRIC GLAND 
B 
Fig. 882.-The mucous membrane of the stomach. A, natural size; B, magnified 25 diameters. In A the 
rugae and the mammillated surface are shown. In B the gland mouths (foveolae gastricae), with the gland tubes 
leading from some of them, and the ridges separating the mouths (plica villosae) are seen. (Cunningham.) 
Fig. 883.-Pyloric gland. 
Fig. 884.-Peptic gastric gland 
ance, from being covered with small shallow depressions or alveoli (joveolae 
gastricae) (Figs. 881 and 882, B) of a polygonal or hexagonal form, which vary THE STOMACH 
1277 
from to 2-0-jy of an inch in diameter, and are separated by slightly elevated 
ridges {plicae villosae). The ridges are most distinct at the pylorus. These 
foveolae are within the areae gastricae. The ridges on section resemble villi. In 
the bottom of the alveola are seen the orifices of minute tubes, the gastric glands 
(Fig. 882 B), which are placed perpendicularly side by side throughout the 
entire substance of the mucous membrane. The surface of the mucous membrane 
of the stomach is covered by a single layer of columnar epithelium; it lines the 
alveoli, and also for a certain distance the mouths of the gastric glands. This 
epithelium commences very abruptly at the cardiac orifice, where the cells sud- 
denly change in character from the stratified epithelium of the oesophagus. The 
cells are elongated, and consist of two parts, the inner or attached portions 
being granular, and the outer or free parts being clear and occupied by a muco- 
albuminous substance. 
The Gastric Glands.-The gastric glands are of three kinds: the true gastric 
glands, the pyloric glands, and the cardiac glands. 
The True Gastric Glands (Fig. 884) are called also the oxyntic glands, the fundus 
glands, and the peptic glands (glandulae gastricae propriae}. They are distributed 
throughout the entire fundus and body, and maybe found even at the pylorus. They 
are tubular in character, and are formed of a delicate basement-membrane, lined 
with epithelium. The basement-membrane consists of flattened transparent endo- 
thelial cells, with processes which extend between and support the epithelium. Into 
the crypt of a true gastric gland three or more caecal tubes, branched or unbranched, 
empty. The duct, however, in these glands is shorter than in the other variety, 
sometimes not amounting to more than one-sixth of the whole length of the gland; 
it is lined throughout by columnar epithelium. At the point where the terminal 
tubes open into the duct, and which is termed the neck, the epithelium alters, and 
consists of short columnar or polyhedral, granular cells, which almost fill the tube, 
so that the lumen becomes suddenly constricted, and is continued down as a very 
fine channel. They are known as the chief or the peptic or the central cells of the 
glands, and furnish pepsin. Between these cells and the basement-membrane are 
found other darker granular-looking cells, studded throughout the tubes at inter- 
vals, and giving it a beaded or varicose appearance. These are known as the 
parietal or oxyntic cells. Some of the parietal cells empty directly into the lumen 
of the gland by secretory capillaries; others empty by a duct which divides into 
secretory capillaries. The parietal cells secrete the acid of the gastric juice. 
Between the glands the mucous membrane consists of a connective-tissue frame- 
work with lymphoid tissue. In places this latter tissue, especially in early life, is 
collected into little masses, which to a certain extent resemble the solitary glands 
of the intestine, and are by some termed the lenticular glands of the stomach. They 
are not, however, so distinctly circumscribed as the solitary glands. 
The Pyloric Glands {glandulae pyloricae) (Fig. 883) are the branched tubular 
glands, and secrete mucus. 
They are placed most plentifully about the pylorus, but between the fundus and 
pylorus, in the region known as the transitional or intermediate zone, both true 
gastric glands and pyloric glands are found. Each pyloric gland consists of two 
or three short, closed tubes opening into a common duct, the external orifice of 
which is situated at the bottom of an alveolus. The caecal tubes are wavy, and 
are of about equal length with the duct. The tubes and duct are lined through- 
out with epithelium, the duct being lined by columnar cells continuous with the 
epithelium lining the surface of the mucous membrane of the stomach, the tubes 
with shorter and more cubical cells, which are finely granular. The pyloric 
glands branch more frequently, are more curved in direction, and open into 
deeper foveolae than the true gastric glands (Szymonowicz). They contain only 
chief or peptic cells and do not possess parietal cells. THE ORGANS OF DIGESTION 
1278 
The Cardiac Glands are found about the oesophageal orifice. They resemble 
the pyloric glands. 
Beneath the mucous membrane, and between it and the submucous coat, is a 
thin stratum of involuntary muscular fibre (muscularis mucosae), which in some 
parts consists only of a single longitudinal layer; in others, of two layers, an inner 
circular, and an outer longitudinal. 
Vessels and Nerves.-The arteries supplying the stomach are-the gastric or 
coronary, the pyloric and the right gastro-epiploic branch of the gastro-duodendal, the 
left gastro-epiploic and vasa brevia from 
the splenic. The gastric artery passes to the 
lesser curvature just below the cardia. It 
gives off the oesophageal branch, and passes 
from left to right along the lesser curva- 
ture of the stomach beneath the perito- 
neum between the two layers of the lesser 
omentum and upon the wall of the stomach. 
It may in this course be a single vessel, or 
may divide into two branches, which run 
along each side of the lesser curvature (Fig. 
886). If there is a single artery it gives off 
six or seven descending branches to the an- 
terior wall and about the same number to 
the posterior wall of the stomach. It also 
gives branches to the lesser omentum. If 
two vascular arches form, one gives branches 
to the anterior wall of the stomach, the other to the posterior wall, and both to 
the lesser omentum. The termination of the gastric anastomoses with the 
pyloric branch or two rami of the pyloric branch of the hepatic artery. From 
each arch six or seven descending branches come off to the anterior and posterior 
PLEXUS 
BENEATH THE 
EPITHELIUM 
GLANDULAR 
PLEXUS 
VEIN 
ARTERIOLE 
PLEXUS OF 
BLOODVESSELS 
IN SUBMUCOUS 
TISSUE 
Fig. 885.-Terminations of the blood-vessels in 
the mucous membrane of the stomach. (Poirier 
and Charpy.) 
SPLENIC 
ARTERY 
SPLEEN 
LEFT GASTRO- 
EPIPLOIC ARTERY 
CORONARY 
ARTERY 
HEPATIC 
ARTERY 
GASTRO-DUODENAL 
ARTERY 
PYLORIC 
ARTERY 
RIGHT GASTRO- 
EPIPLOIC ARTERY 
Fig. 886.-The arteries of the anterior surface of the stomach. (Poirier and Charpy.) 
walls of the stomach. 'The gastro-duodenal artery is given off by the hepatic. 
From the gastro-duodenal comes the right gastro-epiploic. The left gastro- 
epiploic comes from the splenic. The right gastro-epiploic artery passes from 
right to left in the gastro-colic omentum below the greater curvature of the THH STOMACH 
1279 
stomach. The left gastro-epiploic artery passes forward in the gastro-splenic 
ligament to below the greater curvature of the stomach, and passes from left to 
right along that curvature in the gastro-colic omentum, and joins the right gastro- 
epiploic artery. The gastro-epiploic arteries are not upon but are distinctly 
below the stomach wall. From them numerous gastric branches are sent to the 
anterior and posterior walls of the stomach, and they anastomose with branches 
of the gastric and pyloric. Vasa brevia, four or five in number, arise from the 
splenic, pass forward in the gastro-splenic ligament, and supply the fundus. 
The arteries of the stomach lie first beneath the peritoneum, but soon enter the 
muscular coat, supply it, pierce it, ramify in the submucous coat, and are finally 
distributed to the mucous membrane. The arrangement of the vessels in the 
mucous membrane is somewhat peculiar (Fig. 885). The arteries break up at 
the base of the gastric tubules into a plexus of fine capillaries which run upward 
between the tubules, anastomosing with each other, and ending in a plexus of 
larger capillaries, which surround the mouths of the tubes and also form hexagonal 
meshes around the alveoli. 
The capillary networks about the glands give origin to the veins. 'The various 
small veins unite and form a plexus in the submucous tissue (Fig. 885). From this 
plexus come branches which pass through the muscular coat and terminate in the 
right gastro-epiploic branch of the superior mesenteric, the left gastro-epiploic branch 
of the splenic, the veins to the splenic which correspond to the vasa brevia arteries, 
and the gastric or coronary branch of the portal. 
The lymphatics (Figs. 507 and 508) arise in the mucous membrane and terminate 
in a network in the submucous tissue. From this network trunks arise which 
perforate the muscular coat in the regions of the curvatures and terminate in the 
sero-muscular collecting trunks.1 
According to Cuneo, there are three groups of these collectors. Those from the 
lesser curvature pass to the point where the gastric artery reaches the stomach and 
enter the glands along the gastric artery. Those from the greater curvature pass 
from left to right and enter the sub-pyloric glands. Those from the fundus pass 
from right to left and end in the splenic glands. Cuneo further pointed out that 
the region drained by the collectors of the lesser curvature is divided from the 
others by the line shown in Fig. 507. This division exists on both surfaces of 
the stomach. The limit between the collectors which drain into the splenic 
glands and those which drain into the sub-pyloric glands is also shown in 
Fig. 507. Along the lesser curvature the lymph-glands are few in number and 
are limited to the pyloric region, and the lymph-vessels are placed directly upon 
the stomach wall. The lymph-glands and vessels are not upon but are distinctly 
below the greater curvature. 
The subserous and submucous lymphatic networks of the stomach communi- 
cate with the corresponding networks of the oesophagus, but in all probability do 
not communicate with the networks of the duodenum. 
The nerves of the stomach come from the right and left pneumogastrics and from 
the solar plexus of the sympathetic. The left pneumogastric passes to the front 
of the stomach, and the right nerve passes to the back, and they unite with the 
fibres of the sympathetic. The fibres thus formed are mostly non-medullated. 
They form Auerbach's plexus in the muscular coat between the circular and lon- 
gitudinal fibres and Meissner's plexus in the submucous coat, the latter plexus 
being formed by fibres from the former. Fibres from Meissner's plexus ramify 
in the submucous coat and terminate in the muscularis mucosae and the mucous 
membrane, branches passing to the gastric glands and to just beneath the 
epithelium. 
1 The Lymphatics. By Poirier. Cun^o, and Delamare. Translated and edited by Cecil H. Leaf. THE ORGANS OF DIGESTION 
1280 
Movements and Innervation of the Stomach. 
Movements.-It has apparently been demonstrated that the stomach " consists of two parts 
physiologically distinct."1 The cardiac portion of the stomach is a food reservoir in which 
salivary digestion continues; the pyloric portion is the seat of active digestion. Cannon affirms 
that there are no peristaltic waves in the cardiac portion, but that as the food passes from the 
pyloric portion into the intestines, tonic contraction of the muscles of the fundus squeezes the 
contents of the pyloric portion. Moritz, Levan, and Cannon assert that muscular activity is 
chiefly manifested in the pyloric portion. In this portion during digestion there is a succes- 
sion of peristaltic waves, which waves in the human being pass at the rate of three per minute 
(Moritz). Cannon points out that the efficiency of peristalsis in mixing the food depends 
upon the contraction of the pyloric sphincter. So long as the sphincter holds, each constric- 
tion-ring coursing from the middle to the end of the stomach presses the food into a blind pouch; 
the food, unable to escape through the pyloric opening, has as its only outlet the opening in 
the advancing ring. This is an admirable device for bringing the food under the influence of 
the glandular secretions of the pyloric region. For, as a constriction occurs, the secreting sur- 
face enclosed by the narrowed muscular ring is pressed close around the food within the ring. 
As the constriction advances it continually presses inward fresh glandular tissue, and further- 
more, as the constriction advances, a thin stream of food is continuously forced back through 
the ring and thus past the mouths of the glands. The old view that the pyloric sphincter only 
opens after several hours' continuance of the process of digestion and that then the stomach 
empties at once is incorrect. It is emptied in small amounts which escape at frequent intervals 
because of the intermittent opening of the pylorus. When the pylorus is open a wave of peri- 
stalsis forces some of the material from the stomach into the duodenum (Cannon). 
Cannon is of the opinion that the pyloric sphincter is caused to relax by the presence of free 
hydrochloric acid in the pyloric portion of the stomach. When the pylorus is open acid chyme 
passes into the duodenum and acid in the duodenum causes the pylorus to close. The acid 
in the duodenum causes a flow of alkaline pancreatic juice and the acid is neutralized. "As 
the neutralizing proceeds the stimulus closing the pylorus is weakened until the acid in the 
stomach again opens the sphincter."2 
Innervation.-The stomach, as previously shown, has nervous plexuses in its walls and is 
connected to the brain, spinal cord, and sympathetic system. It is probable that gastric peri- 
stalsis is due to a local reflex from Auerbach's plexus (Magnus), the local reflex being inaugu- 
rated by local stimulation, which stimulation, in the words of Bayliss and Starling, "produces 
excitation above and inhibition below the excited spot."3 Reversed peristalsis cannot occur 
if "the reflex mechanism is intact" (Cannon). Cannon in the previously quoted article states 
that cutting the vagus or splanchnic nerves does not destroy the reflex mechanism of the pylorus, 
but, nevertheless, it is markedly affected by the central nervous system. 
Surface Form (see p. 1271).-The cardiac orifice corresponds to the articulation of the 
seventh left costal cartilage with the sternum. The pyloric orifice of the empty stomach is in 
a vertical line drawn from the right border of the sternum, two and a half or three inches below 
the level of the sterno-xiphoid articulation. According to Braune, when the stomach is dis- 
tended, the pylorus moves considerably to the right, as much sometimes as three inches. The 
fundus of the stomach reaches, on the left side, as high as the level of the sixth costal cartilage 
of the left side, being a little below and behind the apex of the heart. The portion of the distended 
stomach which is in contact with the abdominal walls, and is therefore accessible for opening in 
the operations of gastrotomy and gastrostomy, is represented by a triangular space, the base of 
which is formed by a line drawn from the tip of the tenth costal cartilage on the left side to the 
tip of the ninth costal cartilage on the right, and the sides by two lines drawn from the extremity 
of the eighth costal cartilage on the left side to the ends of the base line. 
Surgical Anatomy.-Operations on the stomach are frequently performed, ulcers are excised, 
malignant growths are removed with the associated lymphatic involvement, the entire stomach 
may be removed for cancer, etc. By " gastrotomy" is meant an incision into the stomach for the 
removal of a foreign body, or the arrest of hemorrhage or for exploration, the opening being 
immediately afterward closed-in contradistinction to " gastrostomy," the making of a more or 
less permanent fistulous opening. Gastrotomy is probably best performed by an incision in the 
linea alba, especially if the foreign body is large. The cut may reach from the ensiform car- 
tilage to the umbilicus. The incision may be made over the body itself, where this can be felt, 
or by one of the incisions for gastrostomy, to be mentioned shortly. The peritoneal cavity 
is opened, and the point at which the stomach is to be incised decided upon. This portion is 
then brought out of the abdominal wound and sponges carefully packed around. The stomach 
is now opened by a transverse incision and the foreign body extracted. The wound in the 
stomach is then closed by Lembert sutures-i. e., by sutures passed through the peritoneal, 
1 Walter B. Cannon, Medical News, May 20, 1905, 2 Ibid. 3 Ibid. MOVEMENTS AND INNERVATION OF THE STOMACH 
1281 
muscular and submucous coats in such a way that the peritoneal surfaces on each side of the 
wound are brought into apposition. Gastrostomy was formerly done in two stages by the direct 
method. The first stage consisted in opening the abdomen, drawing up the stomach into the 
external wound, and fixing it there; and the second stage, performed from two to four days 
afterward, consisted in opening the stomach. The operation is now done by a valvular method. 
The following plan is known as the Ssabanejew-Frank operation. An incision is commenced 
opposite the eighth intercostal space, two inches to the left of the median line, and carried 
downward for three inches. By this incision the fibres of the Rectus muscle are exposed and 
these are separated from each other in the same line. The posterior layer of the sheath, the 
transversalis fascia and the peritoneum, are then divided, and the peritoneal cavity is opened. 
Instead of the above incision, the curved incision of Fenger can be made at the margin of the 
left costal cartilages. The anterior wall of the stomach is now seized and drawn out of the 
wound and a silk suture passed through its submucous, muscular, and serous coats at the point 
selected for opening the viscus. This is held by an assistant so that a long conical divertic- 
ulum of the stomach protrudes from the external wound, and the parietal peritoneum and 
the posterior layer of the sheath of the rectus are sutured to the base of the cone. A second 
incision is made through the skin, over the margin of the costal cartilage, above and a little to the 
outer side of the first incision. If Fenger's incision were used, the second incision should be 
above the margin of the cartilages. With a pair of dressing forceps a track is made under the 
skin through the subcutaneous tissue from the one opening to the other and the diverticulum of 
the stomach is drawn along this track by means of the suture inserted into it; so that its apex 
appears at the second opening. A small perforation is now made into the stomach through 
this protruding apex and its margin carefully and accurately sutured to the margin of the 
external wound. The remainder of this incision and the whole of the first incision are then 
closed in the ordinary way and the wound dressed. 
In cases of gastric ulcer, perjoration sometimes takes place, and this was formerly regarded 
as an almost fatal complication. In the present day, by opening the abdomen and closing 
the perforation, which is generally situated on the anterior surface of the stomach, a consider- 
able percentage of cases are cured, provided the operation is undertaken within twelve to fifteen 
hours after the perforation has taken place. The opening is best closed by bringing the peri- 
toneal surfaces on either side into apposition by means of Lembert sutures. 
Pylorectomy or excision of the pylorus is performed, particularly for early cancer, but is also 
done for cicatricial stricture and for ulcer. The mortality after operation for cancer was, until 
recently, very great, but of late years it has been notably reduced, though it is still much higher 
than that which follows operation for any non-malignant condition. 
In operating for cancer, bear in mind Cuneo's study of the lymphatics (page 806). These 
observations indicate that the fundus and two-thirds of the greater curvature are free from 
lymphatic involvement in pyloric cancer.1 In every operable case of cancer of the pylorus the 
entire lesser curvature must be removed up to the gastric artery (Mikulicz's point), and the 
greater curvature must be removed to the left of the involved glands (Hartmann's rule). 
Gastro-enterostomy is an operation which establishes a fistulous communication between the 
stomach and jejunum. The operation is often called gastro-jejunostomy. The opening may be 
made upon either the anterior or the posterior wall of the stomach, between the cardia and the 
seat of pyloric disease. The operation is employed for stricture of the pylorus (benign or 
malignant), and occasionally for ulcer of the stomach. 
Loreta's operation is digital divulsion of the pylorus for cicatricial stricture, the stomach being 
incised transversely near the pylorus to admit the finger, and the wound in the stomach being 
sutured after division has been effected. The operation has been abandoned, because contraction 
recurs. 
Pyloroplasty, or the Heineke-Mikulicz operation, displaced Loreta's operation. In this pro- 
cedure an incision is made through the stricture in the direction of the long axis of the stomach 
and bowel. By making traction on each side of the incision, the longitudinal wound assumes a 
vertical direction, and sutures are inserted so as to close the wound in a vertical line. The method 
of pyloroplasty devised by Finney, of Baltimore, makes a large permanent opening at the 
most dependent part of the stomach, and is the most satisfactory method of which we are 
possessed.2 
Total gastrectomy is the removal of the entire stomach. It is only used for cancer. It was first 
performed by Conner, of Cincinnati. The first successful operation was done by Schlatter, of 
Zurich, in 1898. A number of successes have been reported. It is a justifiable operation only in 
a case in ■which almost the entire stomach is cancerous, in which the viscus is movable, in which 
there are no secondary deposits, and no irremovable diseased glands. 
Gastro-gastrostomy is an operation employed in hour-glass stomach. In this operation an 
anastomosis is made between the pyloric and cardiac ends of the stomach. 
1 William J. Mayo, Annals of Surgery, March, 1904. 
2 Johns Hopkins Hospital Bulletin, July, 1902. 1282 
THE ORGANS OF DIGESTION 
Gastroplication is the operation of suturing the stomach wall into folds or reefs, in order to 
lessen its size. It is employed in some cases of gastric dilatation. 
Gastroptosis is a condition in which the stomach is displaced downward. In some of these 
cases the greater curvature almost reaches the level of the symphysis pubis, and the lesser curva- 
ture is midway between the umbilicus and ensiform cartilage. The condition is usually associated 
with enteroptosis and movable kidney (nephroptosis). In this condition the gastro-hepatic 
omentum and the gastro-phrenic ligament are pulled upon and lengthened. The best operation 
for gastroptosis was devised by Beyea. He applies sutures so as to make folds in and thus shorten 
the stretched ligament and omentum. Thus the stomach is elevated to its proper position, and 
its mobility is not lessened, as it is in other operations which suture it to the abdominal wall. 
THE SMALL INTESTINE (INTESTINUM TENUE). 
The small intestine is a convoluted tube, extending from the pylorus to the 
ileo-caecal valve, where it terminates in the large intestine. It fills up the greater 
part of the abdominal cavity and of the pelvic cavity. It is about twenty feet in 
length,1 and gradually diminishes in size from its commencement to its termina- 
tion. The diameter of the duodenum is almost two inches; the diameter of the 
lower portion of the small intestine is little more than one inch. It is contained 
in the central and lower part of the abdominal cavity, and is surrounded above 
and at the sides by the large intestine; a portion of it extends below the brim of 
the pelvis and lies in front of the rectum; it is in relation, in front, with the great 
omentum and abdominal parietes; and connected to the spine by a fold of peri- 
toneum, the mesentery (p. 1257). The small intestine is divisible into three portions 
-the duodenum, the jejunum, and ileum. 
The Duodenum (Figs. 887, 892, 893, 894, 895). 
The duodenum has received its name from being about equal in length to the 
breadth of twelve fingers (ten inches). It is the shortest, the widest, and the most 
fixed part of the small intestine, being closely and firmly attached to the posterior 
abdominal wall. It does not possess a mesentery. Somewhat more than the 
upper half of the duodenum is placed in the epigastric region; the remainder is in 
the umbilical region. The duodenum, with the exception of the ascending portion, 
is to the right of the median line. Its course presents a remarkable curve, which 
in the adult, as regards the greater part of its extent, is horseshoe-shaped, though 
sometimes, in consequence of the transverse portion being very short or alto- 
gether wanting, it partakes more of the character of the letter V. The opening 
of the horseshoe being directed upward and to the left. In children up to 
the age of about seven the duodenum is annular. The two extremities of 
the duodenum are nearly on the same level, the exit being slightly lower than the 
entrance. 'The two ends are about two inches apart; and between them it 
describes a regular curve embracing the head of the pancreas, the neck of which 
lies between the two extremities of the ring. 
In the adult the course of the duodenum is as follows: commencing at the 
pylorus the direction of the first portion depends upon the amount of distention 
of the stomach and therefore upon the position of the pylorus. When the stomach 
is empty and the pylorus is situated at the right of the upper border of the first 
lumbar vertebra, it is nearly horizontal and transverse; but where the stomach is 
distended, in consequence of the alteration of the position of the pylorus to the 
right the proximal end of the duodenum also becomes altered in position, while the 
1 Treves states that in one hundred cases the average length of the small intestine in the adult male was 22 
feet 6 inches, and in the adult female 2.3 feet 4 inches ; but that it varies very much, the extremes in the male 
being 31 feet 10 inches in one case and 15 feet 6 inches in another, a difference of over 15 feet. He states that 
he has convinced himself that the length of the bowel is independent, in the adult, of age, height, and weight.- 
Ed. of 15th English edition. THE DUODENUM 
1283 
distal end remains fixed and the direction of this portion of the bowel is now 
antero-posterior. Whether directed transversely or antero-posteriorly, it reaches 
Tributary to vena cava. 
Hepatic artery, porta 
vein, and bile duct. 
Crura of Diaphragm. 
Supra- renal 
capsule. 
Gastric artery. 
Splenic 
artery. 
Right 
renal' 
vessels. 
Splenic 
vein. 
Fig. 887.-Relations of duodenum, pancreas, and spleen. (From a cast by Professor Birmingham.1) 
The dotted line represents the line of attachment of the transverse mesocolon. 
the under surface of the liver, where it takes a sharp curve and descends along the 
right side of the vertebral column, for a variable distance, generally to the body of 
1 In the subject from which the cast was taken the left kidney was lower than normal. THE ORGANS OF DIGESTION 
1284 
the fourth lumbar vertebra. It now takes a second bend, and passes across the 
front of the vertebral column from right to left and finally ascends on the left side 
of the vertebral column and aorta to the level of the upper border of the second 
lumbar vertebra and there terminates in the jejunum. As it unites with the 
jejunum it often turns abruptly forward, forming the duodeno-jejunal angle. Prof. 
LIVER 
GASTRO-HEPATIC 
OMENTUM 
DUODENUM: 
SECOND PART 
DUODENUM: 
FIRST PART 
INFERIOR 
VENA 
CAVA 
RIGHT 
KI DN EY 
GREAT 
OMENTUM 
Fig. 888.-Diagram of cross-section of the first 
part of the duodenum, to show its peritoneal 
relations. (Gerrish.) 
Fig. 889.--Diagram of cross-section of the second part 
of the duodenum, to show its peritoneal relations. 
(Gerrish.) 
Birmingham points out that the incomplete ring formed by the duodenum does 
not lie throughout in the same plane. "Its greater part is placed in a transverse 
vertical plane; the middle portion bends strongly backward, around the right side 
of the vena cava, and lies almost in a sagittal plane."1 From the above descriotion 
DUODENUM: 
FOURTH PART 
DUODENUM: 
THIRD PART 
SECO N D 
LUMBAR 
VERTEBRA 
AORTA, VENA CAVA. 
AND RIGHT CRUS 
LEFT 
KIDNEY 
Fig. 890.-Diagram of the third part of the 
duodenum, to show its peritoneal relations. 
(Gerrish.) 
Fig. 891.-Diagram of the fourth part of the duodenum, 
to show its peritoneal relations. (Gerrish.) 
it will be seen that the duodenum may be divided for purposes of description 
into four portions-superior, descending, transverse and ascending. 
The First or Superior Portion (pars superior) (Figs. 887, 892, and 894) is 
very variable in length, but is usually estimated as being about two inches. 
Beginning at the pylorus, it ends at the level of the neck of the gall-bladder. 
1 Prof. Cunningham's Text-book of Anatomy. THE DUODENUM 
1285 
When the stomach is empty this portion of the duodenum is horizontal and 
transverse; when the stomach is distended it extends from before backward. It 
is the most movable of the four portions. It is almost completely covered by peri- 
toneum derived from the two layers of the lesser omentum. A small part of its 
posterior surface is not completely covered by peritoneum (Fig. 888). The first 
inch of the superior portion of the duodenum is completely covered by perito- 
neum ; the lesser omentum is attached above and the greater omentum below (Fig. 
888). The other portion has only its anterior wall covered by peritoneum. The 
posterior and lateral surfaces are uncovered by peritoneum and are near the neck 
of the gall-bladder and the inferior vena cava. The first portion of the duo- 
denum is in such close relation with the gall-bladder that it is usually found to 
be stained by bile after death, especially on its anterior surface. It is in relation 
above and in front with the quadrate lobe of the liver, lying in a slight con- 
cavity, the impressio duodenalis. It is also in relation above in part with the 
gall-bladder; behind with the gastro-duodenal artery, the common bile-duct, and 
the vena porta; and below with the head of the pancreas. The superior portion 
of the duodenum crosses the transverse fissure of the liver, and by means of 
the superior flexure of the duodenum (flexura duodeni superior} passes into the 
second or descending portion beneath the caudate lobe. 
The Second or Descending Portion [pars descendens} (Figs. 887, 892, and 894) 
is between three and four inches in length, and extends from the neck of the gall- 
bladder on a level with the first lumbar vertebra along the right side of the verte- 
bral column as low as the body of the fourth lumbar vertebra. It is crossed in 
its middle third by the transverse colon, the posterior surface of which is uncovered 
by peritoneum and is connected to the duodenum by a small quantity of connective 
tissue. The portions of the descending part of the duodenum above and below 
this interspace are named the supracolic and infracolic portions, and are covered 
in front by peritoneum (Fig. 889). The right side of the supracolic portion is 
covered by peritoneum derived from the anterior surface of the right kidney, the 
left side of the same portion being covered by the peritoneum forming the lesser 
sac. The infracolic part is covered by the right leaf of the mesentery. Pos- 
teriorly the descending portion of the duodenum is uncovered by peritoneum. 
The descending portion of the duodenum is in relation, in front, with the trans- 
verse colon, and above this with the right lobe of the liver, where it lies in the 
impressio duodenalis for the second part of the duodenum; behind with the front of 
the right kidney, to which it is connected by loose areolar tissue, the renal vessels 
and the vena cava inferior; at its inner side is the head of the pancreas, and the 
ductus communis choledochus; to its outer side is the hepatic flexure of the colon. 
The common bile-duct passes downward behind the first portion of the duodenum, 
descends to the inner side of the second portion, is joined by the pancreatic duct, 
and the two ducts perforate the inner side of this portion of the intestine obliquely, 
and empty into the duodenum by a common opening or by two openings at the 
summit of a papilla, some three or four inches below the pylorus. The relations 
of the second part of the duodenum to the right kidney present considerable 
variations. The descending portion passes into the transverse portion by means 
of the flexura duodeni inferior. 
The Third, Pre-aortic, Horizontal or Transverse Portion (pars horizontalis 
inferior} (Figs. 887, 892, and 894) varies much in length; when the duodenum 
assumes the ordinary horseshoe form, it measures from two to three inches; but 
when it presents the rarer V-shaped form, it is practically wanting or very much 
reduced in length. The transverse portion is described as the horizontal part of 
the ascending or last portion by those authors who divide the duodenum into three 
parts instead of four. It commences at the right side of the fourth lumbar vertebra 
and passes from right to left, with a slight inclination upward, in front of the great THE ORGANS OF DIGESTION 
1286 
vessels and crura of the1 Diaphragm, and ends in the fourth portion in front of or 
just to the left of the abdominal aorta. It is crossed by the superior mesenteric 
vessels and mesentery. The posterior surjace rests upon the aorta, the vena cava 
inferior, and the crura of the Diaphragm. By its upper surface this portion of 
the duodenum is in relation with the head of the pancreas. The front of the 
third portion of the duodenum is covered by peritoneum except where the mesen- 
teric vessels and root of the mesentery cross it (Fig. 890). The left side of the 
termination of the ascending portion is also covered by peritoneum, and in this 
region the duodenal fossae are found (p. 1260). 
The Fourth or Ascending Portion of the Duodenum {pars ascendens) (Figs. 
887, 892, and 894) is about two inches long. It ascends on the left side of the 
vertebral column and aorta, as far as the level of the upper border of the second 
lumbar vertebra, where it turns abruptly to the right and forward to become the 
jejunum, forming the duodeno-jejunal angle or flexure (jlexura duodenojejunalis) 
LOBE OF 
SPIGELIUS 
STO MACH 
DIAPHRAGM 
GALL 
GLAD. 
CCELIAC AXIS 
GANGLION OF 
CCELIAC PLEXUS 
SUPERIOR MESEN- 
TERIC ARTERY 
SUSPENSORY 
MUSCLE OF 
DUODENUM 
DUODENO- 
JEJUNAL ANGLE 
T1N F-! 
VEN/if 
111 | 
cava! 
CELLULAR MEMBRANE 
CONNECTING THE PARTS 
OFTHE DUODENALRING 
BEHIND THE PANCREAS 
Fig. 892.-Suspensory muscle of the duodenum or muscle of Treitz. (Poirier and Charpy.) 
(Fig. 892). It is covered entirely in front and partly at the sides by peritoneum, 
derived from the left portion of the mesentery (Fig. 891). The superior mesen- 
teric artery and vein are in front of it. It touches the left kidney, slightly over- 
lapping its inner margin, and rests upon the left crus of the Diaphragm. 
The first part of the duodenum, as stated above, is somewhat movable, but the 
rest is practically fixed and is bound down to neighboring viscera and the posterior 
abdominal wall by the peritoneum. In addition to this, the fourth part of the 
duodenum and the duodeno-jejunal flexure is further bound down and fixed by a 
structure called the Suspensory muscle of the duodenum or the suspensory ligament of 
Treitz (m. suspensorius duodeni) (Fig. 892). This structure commences in the con- 
nective tissue around the coeliac axis and left crus of the Diaphragm, and passes 
downward to be inserted into the superior border of the duodeno-jejunal curve and 
a part of the ascending duodenum, and from this it is continued into the mesentery. 
It possesses, according to Treitz, some few plain muscular fibres mixed with the THE DUODENUM 
1287 
fibrous tissue, of which it is principally made up. It is of little importance as a 
muscle, but acts as a suspensory ligament. 
SOUND IN DUC- 
TUS CHOLEDOCHUS 
CARUNCULA MINOR 
SANTORINI 
VALVULAE 
CONNIVENTES' 
SOUND IN 
ACCESSORY 
PANCREATIC 
DUCT OF 
SANTORINI 
CARUNCULA 
MAJOR 
LONGITUDINAL 
FOLD 
VALVULAE 
CONNIVENTES 
SOUND IN 
DUCTUS CHOLEDOCHUS 
SOUND IN PANCREATIC 
DUCT OF WIRSUNG 
Gastric artery 
Lower end of oesophagus 
Caiiac axis 
Hepatic duct- 
Portal vein- 
Hepatic artery. 
Cystic duct- 
Right suprarenal, 
capsule 
Pyloric orifire- 
Left gastro-epiploic artery 
Duodeno-jejunal junction 
Superior mesenteric artery 
Right gastro-epiploic 
artery 
Superior mesenteric_ 
vein 
Spermatic vessels 
Inferior mesenteric artery 
Spermatic vessels 
Fig. 894.-The duodenum, its four parts marked a, b, c, d. The liver is lifted up ; the greater art of the 
stomach is removed, broken lines indicating its former position. (Testut.) 1288 
THE ORGANS OF DIGESTION 
Interior of the Duodenum (Fig. 893).-In the beginning of the duodenum valvulae 
conniventes are absent. They begin to appear in the lower half of the first portion, 
being at first trivial elevations irregularly placed. They become higher, regular, 
and more numerous lower down, and near the termination of the duodenum are 
strongly marked and closely placed transverse or spiral folds (Fig. 893 and 
p. 1291). In the descending portion (Fig. 893) to the side and rear is a longi- 
tudinal fold (plica longitudincdis duodeni), which is formed by the projection of 
the bile-duct and pancreatic duct beneath the mucous membrane. 
The caruncula major of Santorini or the bile papilla is a projection or tit in the 
lower part of the longitudinal fold. At the summit of this papilla are seen two 
openings, if the bile-duct and pancreatic duct have not united, or one common 
opening for both of them, if they have united. One inch above and half an inch 
or more in front of the bile papilla is a much smaller papilla, the caruncula minor 
of Santorini (papilla duodeni [Santorini]), on the summit of which the accessory 
pancreatic duct of Santorini opens. 
Structure of the Duodenum.-The peritoneal coat (tunica serosa) has been de- 
scribed. The muscular coat (tunica muscularis) is practically identical with the 
muscular coat of the balance of the intestine. The bile-duct and pancreatic duct 
GASTRO- 
DUODENAL 
ARTERY 
GASTRO- 
DUODENAL 
VEIh 
FIRST 
PART OF 
DUODENUM 
C CELIAC 
AXIS 
INFERIOR 
PANCREATICO- 
DUODENAL 
VEIN 
PANCREATICO- 
DUODENAL 
SUPERIOR 
ARTERY 
INFERIOR 
PANCREATICO- 
DUODENAL 
ARTERY 
DUCTUS 
CHOLEDOCHUS' 
ANASTOMOSIS OF THE 
TWO PANCREATICO* 
DUODENAL ARTERIES 
Fig. 895.-The blood-vessels of the duodenum. (Poirier and Charpy.) 
pass through it. The submucous coat (tela submucosa) contains lymph-nodes and 
glands of Brunner (glandulae duodenales). These glands are particularly plenti- 
ful in the first half of the duodenum (p. 1295). The mucous membrane is 
thicker in the duodenum than in the rest of the small intestine, is covered with 
villi, and from the lower half of the first portion down is formed into circular 
folds or valvulae conniventes. In the descending part it exhibits the previously 
described longitudinal fold. 
Vessels and Nerves.-The arteries (Fig. 895) supplying the duodenum are the 
pyloric and pancreatico-duodenal branches of the hepatic, and the inferior pancreatico- 
duodenal branch of the superior mesenteric. The veins (Fig. 895) correspond to 
the arteries. The superior duodenal vein passes into the superior mesenteric, and 
the inferior duodenal vein passes into the portal. The lymphatics pass along with 
the pancreatico-duodenal arteries, glands being present here and there, and 
terminate in the glands about the coeliac axis. The duodenal fossae are described 
on p. 1260. The nerves are derived from the solar plexus. THE JEJUNUM AND ILEUM 
1289 
The Jejunum and Ileum (Figs. 862, 864, 865, 867, 892). 
The remainder of the small intestine from the termination of the duodenum 
comprises the jejunum and ileum; the former name being given to the upper two- 
fifths and the latter to the remaining three-fifths. Spalteholz and others call all of 
the small intestine below the duodenum the intestinum tenue mesenteriale. There 
is no morphological line of distinction between the jejunum and ileum, and the 
division is arbitrary; but at the same time it must be noted that the character of 
the intestine gradually undergoes a change from the commencement of the jeju- 
num to the termination of the ileum, so that a portion of the bowel taken from 
these two situations would present characteristic and marked differences. These 
are briefly as follows: 
Differences between the Jejunum and Ileum.-If the jejunum high up is con- 
trasted with the ileum low down, it is noted that the former is thicker, of greater 
diameter, contains more blood-vessels, and hence is more distinctly red, has well- 
marked valvulae conniventes, but a few small-sized Peyer's patches, and the villi 
are short and broad. In the ileum large Peyer's patches are present in numbers, 
and the villi are thin (Prof. Birmingham). 
The Jejunum {intestinum jejunum).-The jejunum, which derives its name 
from the Latin word jejunus (empty), because it was formerly supposed to be 
empty after death, is wider, its diameter being about one inch and a half, and is 
thicker, more vascular, and of a deeper color than the ileum, so that a given length 
weighs more. Its valvulae conniventes are large and thickly set and its villi are 
larger than in the ileum. The glands of Peyer are almost absent in the upper part 
of the jejunum, and in the lower part are less frequently found than in the ileum, 
and are smaller and tend to assume a circular form. Brunner's glands are only 
found in the upper part of the jejunum. By grasping the jejunum between the 
finger and thumb the valvulae conniventes can be felt through the walls of the 
gut; these being absent in the lower part of the ileum, it is possible in this way 
to distinguish the upper from the lower part of the small intestine. 
The Ileum {intestinum ileum).-The ileum (so called from the Greek word 
sZAsZy, to twist, on account of its numerous coils and convolutions) is placed 
below and to the right of the jejunum. It is narrower, its diameter being one inch 
and a quarter, and its coats are thinner and less vascular than those of the jejunum. 
It possesses but few valvulae conniventes, and they are small and disappear entirely 
toward its lower end, but Peyer's patches are larger and more numerous. The 
jejunum for the most part occupies the umbilical and left iliac regions, while the 
ileum occupies chiefly the umbilical, hypogastric, right iliac, and pelvic regions, 
and terminates in the right iliac fossa by opening into the inner side of the com- 
mencement of the large intestine. The upper portion of the jejunum passes to 
the left of the duodeno-jejunal flexure, and is in relation with the under surface 
of the pancreas and the transverse mesocolon. The lower portion of the ileum is 
in the pelvis and rises from above the brim, passing upward, backward, and to the 
right to reach the ileo-caecal opening. Treves points out that another portion of 
the small intestine may be in the pelvis, viz., the portion with the longest mesentery. 
This is a portion somewhere between a point six feet from the duodenum and a 
point eleven feet from the duodenum. The jejunum and ileum are attached to the 
posterior abdominal wall by an extensive fold of peritoneum, the mesentery (p.1257), 
which allows the freest motion, so that each coil can accommodate itself to changes 
in form and position. The mesentery is fan-shaped; its posterior border, about 
six inches in length, is attached to the abdominal wall from the left side of the 
second lumbar vertebra to the right iliac fossa (Fig. 862). Its length is about eight 
inches from its commencement to its termination at the intestine, and it is rather 
longer about its centre than at either end of the bowel. According to Lockwood, THE ORGANS OF DIGESTION 
1290 
it tends to increase in length as age advances. Between the two layers of which 
it is composed are contained blood-vessels, nerves, lacteals, and lymphatic glands, 
together with a variable amount of fat. 
Meckel's Diverticulum (diverticulum ilei).-Occasionally there may be found 
connected with the lower part of the ileum, on an average about three feet from 
its termination, a blind diverticulum or tube, varying in length, but averaging 
about two inches, and being of about the same diameter as the piece of intestine of 
which it is a part. Sometimes only a portion of the proximal end is open and 
the balance of the structure is obliterated and shrunk to a fibrous cord. In other 
cases the diverticulum is actually of greater diameter than the intestine. It 
usually is at a right angle to the intestine, but may take almost any direction. 
In most cases it has a mesentery. It is attached to and communicates with the 
lumen of the bowel by one extremity, and by the other is unattached or may be 
connected with the abdominal wall or with some other portion of the intestine 
by a fibrous band. This is Meckel's diverticulum, and represents the remains of 
the vitelline or omphalo-mesenteric duct, the duct of communication between the 
umbilical vesicle and the alimentary canal in early foetal life. 
Structure of the Small Intestine, including the Duodenum.-The wall of 
the small intestine is composed of four coats-serous, muscular, areolar or sub- 
mucous, and mucous. 
The Serous Coat (tunica serosa).-The relation of the peritoneum to the duod- 
enum has been described. The remaining portion of the small intestine is sur- 
rounded by the peritoneum, excepting along its attached or mesenteric border; 
here a space is left for the vessels and nerves to pass to the gut. 
The Muscular Coat (tunica muscularis).-The muscular coat consists of two 
layers of fibres, an external or longitudinal layer and an internal or circular 
layer. 
The Longitudinal Fibres (stratum long itudin ale) are thinly scattered over the 
surface of the intestine, and are more distinct along its free border. 
The Circular Fibres (stratum circulare) form a thick, uniform layer; they sur- 
round the cylinder of the intestine in the greater part of its circumference, and are 
composed of plain muscle-cells of considerable length. The muscular coat is 
thicker at the upper than at the lower part of the small intestine. 
The Areolar or Submucous Coat (tela submucosa).-The areolar or submucous 
coat connects together the mucous and muscular layers. It consists of loose, 
filamentous areolar tissue, which forms a bed for the subdivision of the nutrient 
vessels, previous to their distribution to the mucous surface. 
The submucous coat contains lymph-nodules (noduli lymphatici). Each nodule 
is pyramidal or pear-shaped, and the apex lies in the mucous membrane and forms 
a rounded elevation. These rounded elevations mark the solitary glands and 
Beyer's patches (Figs. 896, 898, and 905), and in nowise resemble villi. In the 
duodenum the submucous tissue contains the duodenal glands. The submucous 
tissue is prolonged into the valvulae conniventes. It contains blood-vessels, Meiss- 
ner's plexus of nerves, and lymph-vessels. 
The Mucous Membrane (tunica mucosa).-The mucous membrane is thick and 
highly vascular at the upper part of the small intestine, but somewhat paler and 
thinner below. It consists of the following structures; next the areolar or sub- 
mucous coat is a layer of unstriped muscular fibres, the muscularis mucosae; internal 
to this is a quantity of retiform tissue, enclosing in its meshes lymph-corpuscles, 
and in which the blood-vessels and nerves ramify. Lastly, a basement-membrane, 
supporting a single layer of epithelial cells, which throughout the intestines are 
columnar in character. 'They are granular in appearance, and each possesses a 
clear, oval nucleus. At their superficial or unattached end they present a distinct 
layer of highly refracting material, marked by vertical striae, which were formerly THE JEJUNUM AND ILEUM 
1291 
believed to be minute channels by which the chyle was taken up into the interior 
of the cell, and by them transferred to the lacteal vessels of the mucous membrane. 
MOUTHS OF GLANDS 
OF LIEBERKUHN 
SOLITARY GLAND 
Fia. 896.- Free surface of the mucous membrane of the small intestine, showing villi, solitary glands, 
and openings of the intestinal glands. Semidiagrammatic. (Testut.) 
The mucous membrane presents for examination the following structures con- 
tained within it or belonging to it: 
Valvulae conniventes. 
Villi. 
Simple follicles. 
Duodenal glands. 
Lymphatic nodules 
Solitary glands. 
Peyer's or agminate glands. 
rPhe Valvulae Conniventes or the Valves of Kerkring {plicae circulares [Kerkringi]) 
(Fig. 897) are large folds or valvular flaps projecting into the lumen of the bowel. 
They are composed of reduplications or folds of the mucous membrane, the two 
layers of the fold being bound together by submucous tissue; they contain no 
muscular fibres, and, unlike the folds in 
the stomach, they are permanent, and 
are not obliterated when the intestine is 
distended. The majority extend trans- 
versely across the cylinder of the intestine 
for about one-half or two-thirds of its 
circumference, but some form complete 
circles, and others have a spiral direc- 
tion; the latter usually extend a little 
more than once around the bowel, but 
occasionally two or three times. The 
spiral arrangement is the characteristic 
one of the shark family of fishes. The 
larger folds are about one-third of an 
inch in depth at their broadest part; but 
the greater number are of smaller size. 
The larger and smaller folds alternate 
with each other. They are not found at the commencement of the duodenum, 
but begin to appear about one or two inches beyond the pylorus. In the lower 
part of the descending portion, below the point where the bile and pancreatic 
ducts enter the intestine, they are very large and closely approximated. In 
the transverse portion of the duodenum and upper half of the jejunum they 
Fig. 897.-Valvulae conniventes in the upper part 
of the small intestine. (Poirier and Charpy.) 1292 
THE ORGANS OF DIGESTION 
are large and numerous; and from this point, down to the middle of the ileum, 
they diminish considerably in size. In the lower part of the ileum they almost 
entirely disappear; hence the comparative thinness of this portion of the intes- 
tine as compared with the duodenum and jejunum. The valvulae conniventes 
retard the passage of the food along the intestine, and afford a more extensive 
surface for absorption. 
The Villi (villi intestinales) (Figs. 896, 898, 899, 900, and 905) are minute, highly 
vascular processes, never larger than one millimetre, projecting from the mucous 
membrane of the small intestine throughout its whole extent, and giving to its 
surface a velvety appearance. They spring from the valvulae conniventes and also 
from the spaces between them. In shape, according to Rauber, they are short 
and leaf-shaped in the duodenum, tongue-shaped in the jejunum, and filiform 
PLANE OF MU- 
COUS SURFACE 
Fig. 898.-Mucosa of small intestine in ideal vertical cross-section. (Testut, after Heitzmann.) 
in the ileum. They are largest and most numerous in the duodenum and 
jejunum, and become fewer and smaller in the ileum. Krause estimates their 
number in the upper part of the small intestine at from fifty to ninety in a square 
line; and in the lower part from forty to seventy, the total number for the whole 
length of the intestine being about four millions. 
Structure of the Villi (Figs. 899 and 900).-The structure of the villi has 
been studied by many eminent anatomists. We shall here follow the description 
of Watney,1 whose researches have a most important bearing on the physiology of 
that which is the peculiar function of this part of the intestine, the absorption of fat. 
The essential parts of a villus are-the lacteal vessel, the blood-vessels, the 
epithelium, the basement-membrane and muscular tissue of the mucosa, these 
structures being supported and held together by retiform lymphoid tissue. 
Phil. Trans., vol. clxv. part ii. THE JEJUNUM AND ILEUM 
1293 
Fig. 899.-Diagrammatic section of a villus, ep. Epithelium only partially shaded in. I. Central chyle- 
vessel ; the cells forming the vessel have been less shaded to distinguish them from the cells of the parenchyma 
of the villus, m. Muscle-fibres running up by the side of the chyle-vessel. It will be noticed that each muscle- 
fibre is surrounded by the reticulum, and by this reticulum the muscles are attached to the cells forming the 
membrana propria, as at e1, or to the reticulum of the villus. Ic. Lymph-corpuscles, marked by a spherical 
nucleus and a clear zone of protoplasm. I'. Upper limit of the chyle-vessel, e, e, e'. Cells forming the mem- 
brana propria. It will be seen that there is hardly any difference between the cells of the parenchyma, the endo- 
thelium of the upper part of the chyle-vessel, and the cells of the membrana propria. V. Blood-vessels, z. Dark 
line at base of the epithelium formed by the reticulum. It will be seen that the reticulum penetrates between 
all the other elements of the villus. The reticulum contains thickenings or " nodal points." The diagram shows 
that the cells of the upper part of the villus are larger and contain a larger zone of protoplasm than those of the 
lower part. The cells of the upper part of the chyle-vessel differ somewhat from those of the lower part in that 
they more nearly resemble the cells of the parenchyma. (Watney.) 
Capillaries. 
Lymph trunk.- 
Lymph trunk. 
Capillaries. 
Small artery. 
Lymphatic plexus. 
Fig. 900.-Villi of small intestine. (Cadiat.) 1294 
THE ORGANS OF DIGESTION 
These structures are arranged in the following manner: situated in the centre 
of the villus is the lacteal, terminating near the summit in a blind extremity; 
running along this vessel are unstriped muscular fibres; surrounding it is a plexus 
of capillary vessels, the whole being enclosed by a basement-membrane, and cov- 
ered by columnar epithelium. Those structures which are contained within the 
basement-membrane-namely, the lacteal, the muscular tissue, and the blood- 
vessels-are surrounded and enclosed by a delicate reticulum which forms the 
matrix of the villus, and in the meshes of which are found large, flattened cells 
with oval nuclei, and, in smaller numbers, lymph-corpuscles. These latter are 
to be distinguished from the larger cells of the villus by their behavior with 
reagents, by their size, and by the shape of the nucleus, which is spherical. 
Transitional forms, however, of all kinds are met with between the lymph-cor- 
puscles and the proper cells of the villus. Nerve-fibres are contained within the 
villi; they form ramifications throughout the reticulum. 
The lacteals are in some cases double, and in some animals multiple. Situated 
in the axis of the villi, they commence by dilated caecal extremities near to, but 
not quite at, the summit of the villus. The walls are composed of a single layer 
of endothelial cells, the interstitial substance between the cells being continuous 
with the reticulum of the matrix. 
.CALCI FORM 
CELL 
_GLAN DU LAR 
'cell 
CELL OF 
PANETH 
Fig. 901.-Section of a gland of Lieberkuhn in the mouse. 
(Paneth.) 
Fig. 902.-Transverse section of crypts of 
Lieberkuhn. (Klein and Noble Smith.) 
The muscular fibres are derived from the muscularis mucosae, and are arranged 
in bundles around the lacteal vessel, extending from the base to the summit of the 
villus, and giving off laterally individual muscle-cells, which are enclosed by the 
reticulum, and by it are attached to the basement-membrane. 
The blood-vessels form a plexus between the lacteal and the basement-mem- 
brane, and are enclosed in the reticular tissue; in the interstices of the capillary 
plexus, which they form, are contained the cells of the villus. 
These structures are surrounded by the basement-membrane, which is made 
up of a stratum of endothelial cells, and upon which is placed a layer of columnar 
epithelium. The reticulum of the matrix is continuous through the basement- 
membrane (that is, through the interstitial substance between the individual 
endothelial cells) with the interstitial cement substance of the columnar epithelial 
cells on the surface of the villus. Thus we are enabled to trace a direct continuity 
between the interior of the lacteal and the surface of the villus by means of the 
reticular tissue, and it is along this path that the chyle passes in the process of 
absorption by the villi; that is to say, it passes first of all into the columnar THE JEJUNUM AND ILEUM 
1295 
epithelial cells, and, escaping from them, is carried into the reticulum of the villus, 
and thence into the central lacteal. 
The Simple Follicles, Intestinal Glands, Crypts or Glands of Lieberkiihn (glandulac 
intestinales [Lieberkuhni]) (Figs. 901, 902, and 905) are found in considerable 
numbers over every part of the mucous membrane of the small intestine. They 
consist of minute tubular depressions of the mucous membrane, arranged per- 
pendicularly to the surface, upon which they open by small circular apertures. 
They may be seen with the aid of a lens, their orifices appearing as minute dots 
scattered between the villi (Fig. 896). Their walls are thin, consisting of a base- 
ment-membrane lined by columnar epithelium, and covered on their exterior by 
capillary vessels. 
The Duodenal or Brunner's Glands {glandulae duodenales [Brunneri\) are limited 
to the duodenum and commencement of the jejunum. They are small, flattened, 
granular bodies embedded in the submucous areolar tissue, and open upon the 
surface of the mucous membrane by minute excretory ducts. They are most 
numerous and largest near the pylorus. They are small, compound, acino-tubular 
glands, and much resemble the small glands which are found in the mucous mem- 
■•Capillary network. 
Large 
circular 
vessel. 
Fig. 903.-Transverse section through the equatorial plane 
of three of Peyer's follicles from the rabbit. 
Fig. 904.-Patch of Peyer's glands. From the 
lower part of the ileum. 
brane of the month. They are believed by Watney to be direct continuations of 
the pyloric glands of the stomach. They consist of a number of tubular alveoli, 
lined by epithelium, and opening by a single duct on the inner surface of the 
intestine. 
The Lymph Nodules {noduli lymphatici) are small pyriform structures. The 
bodies of the nodes are in the submucous coat; the apices are in the mucous mem- 
brane, which is thrown by them into rounded elevations. They are divided into 
solitary glands and Peyer's glands. 
The solitary glands (noduli lymphatici solitarii) (Figs. 896 and 898) are found 
scattered throughout the mucous membrane of the small intestine and the large 
intestine. In the small intestine they are most numerous in the lower part of the 
ileum, upon and between the valvulae conniventes. They are small, round, whitish 
bodies, from one-twenty-fourth of an inch to one-quarter of an inch in diameter. 
Their free surface is covered with villi, and each gland is surrounded by the THE ORGANS OF DIGESTION 
1296 
openings of the follicles of Lieberkuhn. They are now recognized as lymph- 
nodules. They consist of a dense interlacing retiform tissue closely packed with 
lymph-corpuscles and permeated with an abundant capillary network. The inter- 
spaces of the retiform tissue are continuous with larger lymph-spaces at the base 
of the gland, through which they communicate with the lacteal system. They 
are situated partly in the submucous tissue, partly in the mucous membrane, 
whence they form slight projections of its epithelial layer, after having pene- 
trated the muscularis mucosae. The villi situated on them are generally absent 
from the very summit (or "cupola," as Frey calls it) of the gland. 
Peyer's glands, Peyer's patches, the agminated glands or the tonsillae intestinales 
(noduli lymphatici aggregati \Peyeri\) (Figs. 903, 904, and 905) may be regarded as 
aggregations of solitary glands, forming circular or oval patches from twenty-five 
to forty in number, and varying in length from half an inch to four inches. They 
are largest and most numerous in the ileum. In the lower part of the jejunum 
they are small, of a circular form, and few in number. They are occasionally seen 
in the duodenum. They are placed lengthwise in the intestine, and are situated 
INTESTINAL VILLUS 
GLAND OF LIEBERKUHN 
CHYLI FERGUS 
DUCT 
SUMMIT OF 
'FOLLICLE 
MIDDLE FOLLICULAR 
ZONE 
PERIFOLLICULAR 
LYM PHATIC ZONE 
BASE OF 
FOLLICLE 
INFERIOR LYM- 
PHATIC PLEXUS 
Fig. 905.-Vertical cell of a Peyer's patch in a man with the lymphatic vessels injected. (Frey.) 
in the portion of the tube most distant from the attachment of the mesentery. 
Each patch is formed of a group of the above-described solitary glands covered 
with mucous membrane, and in almost every respect are similar in structure to 
them. They do not, however, as a rule, possess villi on their free surface. Each 
patch is surrounded by a circle of the crypts of Lieberkuhn. They are best marked 
in the young subject, becoming indistinct in middle age, and sometimes altogether 
disappearing in advanced life. They are largely supplied with blood-vessels, 
which form an abundant plexus around each follicle and give off fine branches 
which permeate the lymphoid tissue in the interior of the follicle. The lacteal 
plexuses which are found throughout the small intestine are especially abundant 
around these patches; here they form rich plexuses with sinuses around the glands 
(Fig. 905). In typhoid fever there is ulceration of Peyer's patches. 
Vessels and Nerves.-The arteries (vasa intestini tenuis') are branches of the 
superior mesenteric (Fig. 420) and ascend within the mesentery, forming single, 
double, or even tertiary loops (Figs. 869, 870, 871, 872, 873, 874, and 906). The 
terminal branches reach the intestine, and each branch divides into two, one going 
to each side of the intestine and passing transversely around it. At first they are THE JEJUNUM AND ILEUM 
1297 
directly beneath the peritoneum, but after a time they pass to the submucosa 
and form a plexus, from which branches go to the mucous membrane. Some 
of these enter the villi; others form plexuses about the glands of Lieberkuhn 
(Birmingham). 
Fig. 906.-A loop of small intestine, showing the mode of distribution of the arteries. (Testut.) 
Dr. George H. Monks1 points out that opposite the upper portion of the bowel 
the mesenteric vessels form only primary loops; as we pass down secondary loops 
appear, become larger and more and more numerous, and actually prominent 
features about the fourth foot. As we descend the secondary 
loops become larger and more numerous and the primary 
become smaller. All the time the loops get nearer and 
nearer to the bowel. Tertiary loops may appear. Opposite 
the lower part of the ileum the loops cease to be character- 
istic and they form a network. (Monks's views are fully 
set forth on pp. 1266, 1267, and 1268.) In the upper part 
of the gut the vasa recta are from 3 to 5 cm. long, when the 
loop of small intestine to which they run is lifted up so as 
to put them gently on the stretch. They are straight, large, 
and regular, and rarely give off branches in the mesentery. 
In the lower third they are very short, being generally less 
than 1 cm. in length. Here they are less straight, smaller, 
less regular, and have frequent branches in the mesentery. 
The veins correspond to the arteries, and the venous 
blood passes to the superior mesenteric vein, which, it will be 
remembered, unites with the splenic vein to form the portal 
vein. The mesenteric veins are devoid of valves. 
The lacteals are lymphatics (Figs. 898, 899, 900, and 
905) which arise in the villi. Lymphatics also begin in 
sinuses at the base of the solitary glands and as lymph- 
nodes in the submucous coat. Peyer's patches are aggre- 
gations of lymph-nodes. There is an extensive lymphatic 
plexus in the submucous coat, another in the muscular coat, 
another under the peritoneum. The submucous plexus 
is formed by lymphatics from the villi and mucous membrane. This plexus 
is joined by lymphatics from the bases of the solitary glands, and the lymph 
passes by vessels to larger vessels at the mesenteric < border of the gut. The 
muscular lymphatics are placed between the two muscular layers. They 
Fig. 907.-Nerve endings 
in the villi of the small in- 
testineof arabbit. (Mailer.) 
1 Annals of Surgery, May, 1903. 1298 
THE ORGANS OF DIGESTION 
form a plexus and communicate freely with the lymphatics from the mucous 
membrane, and empty themselves in the same manner into the commencement 
Fig. 908.-Meissner's plexus. 
a 
Multipolar ganglion-cells. 
I 
b 
Single ganglion-cell. 
Fig. 909 -Meissner's plexus. (Klein and Noble Smith.) THE LARGE INTESTINE 
1299 
of the lacteal vessels at the attached border of the gut. The vessels from all 
sources of lymphatic supply pass up between the two layers of the mesentery, 
being connected with the mesenteric glands (Fig. 509), and unite to form a trunk, 
the intestinal lymphatic trunk, which opens into the receptaculum chyli, or the 
vessels unite to form several trunks, which open separately into the receptaculum 
chyli. 
The nerves of the small intestine (Figs. 907, 908, and 909) are derived from the 
coeliac plexus about the superior mesenteric artery, which is one of the divisions 
of the solar plexus. They pass along within the mesentery with the superior mesen- 
teric artery and reach the intestine. They pass to the plexus of nerves and ganglia 
situated between the circular and longitudinal muscular fibres (Auerbach's plexus), 
from which the nervous branches are distributed to the muscular coats of the 
intestine. From this plexus a secondary plexus is derived (Meissner's plexus). 
It is formed by branches which have perforated the circular muscular fibres 
(Fig. 909). This plexus lies between the muscular and mucous coats of the intes- 
tine. It is also gangliated, and from it the ultimate fibres pass to the muscularis 
mucosae, to the villi, and to the mucous membrane. The nerves of the intestine 
are non-medullated, and some of the fibres are derived from the pneumogastric. 
THE LARGE INTESTINE (INTESTINUM CRASSUM) (Figs. 799,861,865,910, 911). 
The large intestine extends from the termination of the ileum to the anus. It 
is about five feet or more in length, being one-fifth of the whole extent of the 
SACCULATIONS 
Fig. 910.-Large intestine. A piece of transverse colon from a child two years old. The three chief charac- 
teristics of the large intestine-sacculation, taeniae and appendices epiploicae-are shown. (Cunningham.) 
APPENDICES EPIPIOICAE 
MUSCULAR BAND 
intestinal canal. It is largest at its com- 
mencement at the caecum, and gradually 
diminishes as far as the rectum, where 
there is a dilatation of considerable size 
just above the anus. The diameter of the 
distended caecum is usually about three 
inches; the diameter of the descending 
colon is about one and a half inches. 
The large intestine differs from the small 
intestine in its greater size, its more 
fixed position, its sacculated form (Figs. 
910and 911),and in possessing certain ap- 
pendages to its external coat, the appendices 
epiploicae (Fig. 910). The appendices 
epiploicae are peritoneal pouches con- 
taining fat, unless the subject is greatly 
wasted; they protrude here and there from the peritoneal coat of the entire large 
bowel, except the rectum, and are particularly frequent along the anterior longi- 
INTERIOR OF. 
SACCULE 
MUSCULAR 
BAND 
MUSCULAR 
BAN D 
Fig. 911.-Segment of large intestine, showing the 
characteristic features of its structure. (Testut.) THE ORGANS OF DIGESTION 
1300 
tudinal band. Further, the longitudinal muscular fibres of the large intestine do 
not form a continuous layer around the gut, but are arranged in three longitudinal 
bands or taeniae (taeniae coli) (Fig. 911). The large intestine, in its course, describes 
an arch, which surrounds the convolutions of the small intestine. It commences 
in the right inguinal region, in a dilated part, the caecum. It ascends through the 
right lumbar and right hypochondriac regions to the under surface of the liver; 
it here takes a bend to the left, the hepatic flexure, and passes transversely across 
the abdomen on the confines of the epigastric and umbilical regions, to the left 
hypochondriac region; it then bends again, the splenic flexure, and descends 
through the left lumbar region to the left iliac fossa, where it becomes convoluted, 
and forms the sigmoid flexure; finally it enters the pelvis, and descends along its 
posterior wall to the anus. The large intestine is divided into the caecum, colon, 
and rectum. 
The Caecum (Intestinum Caecum) (Figs. 912, 913). 
The caecum, the commencement of the large intestine, is the large blind pouch, 
or cul-de-sac, situated below the ileo-caecal valve. Its name is derived from 
caecus, blind. Its blind end or fundus is directed downward, and its open end 
upward, communicating directly with the 
colon, of which this blind pouch appears to 
be the beginning or head, and hence the old 
name caput caecum coli was applied to it. 
An incomplete groove marks the upper limit 
of the caecum. This groove is at the level 
of the opening of the ileum. When the 
caecum is contracted it bends on this groove 
as on a hinge and forms an angle with the 
ascending colon. In the contracted caecum 
sacculations are but slightly evident; in the 
distended caecum they are definite. Its size 
is variously estimated by different authors, 
but on an average it may be said to be two 
and a half inches in length and three in 
breadth. In 435 careful autopsies, Byron 
Robinson found the caecum and appendix 
congenitally absent in one case.1 The same 
author says that excessively large caeca are 
found in a little less than one-third of all 
autopsies. A large caecum may be four 
inches in width, entirely surrounded by peri- 
toneum and usually is excessively mobile. 
Sometimes an excessively small caecum is 
encountered. According to Byron Robinson, this results from diminution of the 
blood-supply during the axial rotation and caecal descent of development. An 
adult caecum may be only one inch in width and one-half an inch in length, and it 
is usually devoid of mobility. It is situated in the right iliac fossa, above the outer 
half of Poupart's ligament, usually rests on the Ilio-psoas muscle, the iliac fascia 
intervening, and lies immediately behind the abdominal wall. The right side of 
the caecum is in contact with the outer wall of the abdomen, and the outer aspect 
of the anterior wall of the caecum is in contact with the anterior abdominal wall 
(Spalteholz). When the caecum is full the small intestine lies in front of the left 
Fig. 912.-The caecum and colon laid open 
to show the ileo-caecal valve. 
1 St. Louis Courier of Medicine, October-December, 1902. THE CAECUM 
1301 
side and lower portion of the anterior caecal wall. If the caecum is empty the 
small intestine lies in front of its anterior wall, and the lower end is on a higher 
level than when this portion of the gut is full. In 15 per cent, of cases the caecum 
is covered by the omentum (Byron Robinson). Byron Robinson describes four 
positions of the caecum: 1. On the Psoas muscle. 2. To the right of the Psoas 
muscle. 3. In the pelvis. 4. The potential position, in which it lies free in the 
abdominal cavity. It may be found in various positions in the abdomen, 
because of elongation of the fixation apparatus. The commonest position is on the 
Psoas muscle, and this position is even more common in men than in women. It 
is twice as often in the pelvis in women as in men-20 per cent, of cases in the 
former; 10 per cent, in the latter. As a rule, it is entirely enveloped on all sides 
by peritoneum, but in a certain number of cases (6 per cent., according to Berry) 
the peritoneal covering is not complete, so that a small portion of the upper end 
of the posterior surface is uncovered and connected to the iliac fascia by connec- 
tive tissue. As a matter of fact, there is no real mesocaecum-meaning by the term 
a peritoneal fold which holds the caecum to the dorsal wall of the abdomen-except 
when there is failure in development. The normal caecum is completely invested 
by peritoneum from the beginning. Originally the caecum receives its blood along 
a single peritoneal fold, the ileo-caecal fold, which is a simple mesentery. As 
development advances, this simple mesentery becomes a double fold and prac- 
tically bloodless, and is replaced by two vascular folds, the mesoappendix to 
the left and the mesenterico-colicum to the right. The mobility of the caecum 
varies. Very small caeca are fixed. In most cases the caecum lies quite free in the 
abdominal cavity and enjoys a considerable amount of movement. Sometimes 
it is excessively mobile, and in such cases is usually also of large size. Such 
mobility is due to a stretched fixation apparatus. A very large and mobile 
caecum may be made to come in contact with any abdominal viscus and may 
enter any hernial sac on either side. As a rule, when the caecum is large and mobile, 
it is found in the pelvis or in the middle of the abdomen (Byron Robinson). It 
is to be remembered that a mobile caecum carrying with it the appendix may 
pass to almost any region of the abdomen. Sometimes the caecum fails to descend 
or only descends a part of the way during development, the axial rotation of the 
intestinal tract having been arrested. In such a case it may terminate at the 
level of the gall-bladder, and the ascending colon is absent. In 310 adult males 
Byron Robinson found 8 per cent, with undescended caecum and appendix. 
Non-descent is found in less than 4 per cent, of adult females. A partly descended 
caecum usually lies upon the right kidney. 
The caecum varies in shape, but, according to Treves, in man it may be classified 
under one of four types (Fig. 913). In early foetal life it is short, conical, and 
broad at the base, with its apex turned upward and inward toward the ileo-caecal 
junction. It then resembles the caecum of some of the monkey tribe, e. g., Man- 
gabey monkey. As the f<etus grows the caecum increases in length more than in 
breadth, so that it forms a longer tube than in the primitive form and without the 
broad base, but with the same inclination inward of the apex toward the ileo- 
caecal junction. This form is seen in others of the monkey tribe, e. g., the spider 
monkey. As development goes on, the lower part of the tube ceases to grow and 
the upper part becomes greatly increased, so that at birth there is a narrow tube, 
the vermiform appendix, hanging from a conical projection, the caecum. This is 
the infantile form, and as it persists throughout life, in about 2 per cent, of 
cases, it is regarded by Treves as the first of his four types of human caeca. The 
caecum is conical and the appendix rises from its apex. The three longitudinal 
bands start from the appendix and are equidistant from each other. In the second 
type, the conical caecum has become quadrate by the growing out of a saccule on 
either side of the anterior longitudinal band. These saccules are of equal size, 1302 
THE ORGANS OF DIGESTION 
and the appendix arises from between them, instead of from the apex of a cone. 
'This type is found in about 3 per cent, of cases. The third type is the normal type 
of man. Here the two saccules, which in the second type were uniform, have 
grown at unequal rates: the right with greater rapidity than the left. In conse- 
quence of this an apparently new apex has been formed by the growing downward 
of the right saccule, and the original apex, with the appendix attached, is pushed 
over to the left toward the ileo-caecal junction. The three longitudinal bands still 
start from the base of the appendix, but they are now no longer equidistant from 
each other, because the right saccule has grown between the anterior and postero- 
external bands, pushing them over to the left. This type occurs in about 90 per 
cent, of cases. The fourth type is merely an exaggerated condition of the third; 
Fig. 913.-The four types of caecum. 
the right saccule is still larger, and at the same time the left saccule has been 
atrophied, so that the original apex of the caecum, with the appendix, is close to 
the ileo-caecal junction, and the anterior band courses inward to the same situa- 
tion. This type is present in about 4 per cent, of cases. 
Supports of the Caecum.-According to Byron Robinson,1 the caecum is main- 
tained in position by the mesocolon and a peritoneal fold, the right phrenico-colic 
ligament, which arises from the hepato-duodenal and hepato-renal ligaments. It 
receives support from the connective tissue about vessels and nerves, and 
inconstantly from folds which fixes it in the iliac fossa and in the region of the 
vena cava. 
1 St. Louis Courier of Medicine, October-December, 1902. THE CAECUM 
1303 
The Interior of the Caecum.-In the interior of the caecum are seen depressions 
which correspond to the surface haustra, and semilunar folds (plicae semilunares 
coli) (Fig. 912), which correspond to the transverse surface constrictions. There 
are three openings in the caecum: that into the colon; that into the ileum, which 
is guarded by the ileo-caecal valve (p. 1308); and that into the appendix, which 
may be guarded by the valve of Gerlach. 
Pericaecal Folds and Fossae.-See p. 1262, and Figs. 866, 867, and 868. 
The Vermiform Appendix (processus vermiformis) (Figs. 866,867,868,913,914, 
915, 916, and 918) .-The vermiform appendix is found only in man, the higher 
apes, and the wombat, although in certain rodents a somewhat similar arrangement 
exists. In carnivorous animals the caecum is very slightly developed; in her- 
bivorous animals (with a simple stomach) it is, as a rule, extremely large. It has 
been suggested that the vermiform process in man is the degenerated remains of the 
herbivorous caecum, which has been replaced by the carnivorous form.1 The 
vermiform appendix is a long, narrow, worm-shaped, musculo-membranous tube, 
which starts from what was originally the apex of the caecum. After development 
has advanced the vermiform appendix comes off, as a rule, from the inner side of 
the posterior wall of the caecum that is below and behind the termination of the 
ileum. This origin usually corresponds to McBurney's point, which is in the 
abdominal wall, midway between the umbilicus and the anterior superior iliac 
spine and which is the usual seat of the greatest tenderness in appendicitis. The 
origin of the appendix varies with the type of caecum present. These variations 
are shown in Fig. 913. In the foetal or infantile type of appendix it arises from 
the apex of the caecum; in the second type of caecum it arises between the two 
caecal sacculi; in the third type it arises between a large outer and a small inner sac- 
culus; and on the posterior wall of the caecum, the excessive growth of the anterior 
wall having caused the appendix to originate posteriorly; in the fourth type there is 
no internal sacculus, and the appendix arises from the posterior caecal wall behind 
the ileo-caecal junction (p. 1302). The movable portion of the appendix maybe 
met with in different situations. It may pass upward and in front of the caecum 
and colon, upward and behind the caecum, and even behind the colon between the 
two layers of the mesocolon; upward and to the inner side, or upward and to the outer 
side of the caecum and colon. It may pass to the left under the ileum and mesentery, 
upward and to the left or downward and to the left into the true pelvis. It may pass 
directly downward under the caecum. It may pass to the right in front of or back 
of the caecum. It may occupy any one of the caecal fossae (p. 1262), but most often 
enters the ileo-caecal fossa. In unusual cases the appendix is found in the inguinal 
canal as a portion of or the sole contents of a hernia; adherent to the parietal peri- 
toneum in front of or to the side of the caecum, or "behind the peritoneum, below 
the caecum, adherent to the under surface of the caecum and in contact with its 
muscular wall and covered by its peritoneal coat."2 When the caecum is mobile 
the appendix may be found almost anywhere within the abdomen. When the 
caecum is undescended the appendix, of course, shares in the failure to descend, 
and may be below the gall-bladder or in front of the right kidney, and may pass 
in several directions: upward behind the caecum; to the left behind the ileum and 
mesentery; or downward and inward into the true pelvis. It varies from one-half 
an inch to nine inches in length, its average being about three inches. Its diameter, 
is from one-eighth inch to one-quarter inch. The operating surgeon may occa- 
sionally fail to find an appendix buried in one of the caecal fossae, and may con- 
clude that the diverticulum is absent. As a matter of fact, unless the colon is also 
absent, it seems doubtful if the appendix is ever absent, except as a result of dis- 
1 Cunningham's Text-book of Anatomy. 
2 Deaver's Surgical Anatomy. THE ORGANS OF DIGESTION 
1304 
ease. This view is maintained by Lockwood and Rolleston,1 by Kelynack,2 and 
others. It is asserted by some that the appendix is absent five times out of 10,000 
autopsies. It is retained in position by a fold of peritoneum derived from the left 
leaf of the mesentery, which forms a mesentery for it, and is called the meso- 
appendix (p. 1260, and Figs. 866, 867, and 868). In color the healthy appendix is 
yellowish-pink, is soft and smooth to the touch, and the "subperitoneal vessels 
are barely visible."3 The canal of the appendix is small and extends throughout 
the whole length of the tube. The walls of the healthy diverticulum are thick, 
and the diameter of the lumen is usually trivial as compared with the diameter of 
the appendix itself. The lumen of the appendix communicates with the caecum 
by an orifice which is placed below and behind the ileo-caecal opening (Fig. 919). 
It is sometimes guarded above and to the left side by a semilunar fold of mucous 
membrane, the valve of Gerlach (valvula processus vermijormis'). The valve is 
inconstant, and is never perfect. It is stated that the appendix tends to undergo 
obliteration as an involution change in a functionless organ. The lumen rarely 
contains foreign bodies after death, but often contains fecal concretions. Certain 
it is that in 25 per cent, of necropsies upon adults or elderly people the lumen 
is found to be partially or completely occluded. 
ILEOCOLIC ARTERY 
ANTERIOR ILEO- 
CAECAL ARTERY 
ANTERIOR CAECAL 
ARTERY 
ILEUM 
APPENDICULAR 
ARTERY 
APPEN DIX 
VERM I FORM IS 
Fig. 914. Arteries of the caecum and of the appendix vermiformis and of the terminal portion of the ileum. 
(Poirier and Charpy.) 
Structure of the Appendix (Fig. 917).-The coats of the appendix correspond to 
the coats of the bowel: serous, muscular (the outer layer of longitudinal, the inner 
of circular fibres), submucous, and mucous. In the deepest portion of the mucous 
coat, against the submucous coat, are the unstriated fibres constituting the mus- 
cularis mucosae. The muscularis mucosae is often present in some regions and 
absent in others. It may not be present at all. 
The Outer or Serous Coat usually completely covers the appendix and has a 
definite mesentery, the mesoappendix (p. 1260). Occasionally the base of the 
appendix is not surrounded by peritoneum, but is extraperitoneal, lying in the 
retroperitoneal tissue. The appendiculo-ovarian ligament of Clado is occasionally 
present in females. It is a prolongation of the mesoappendix which passes into 
the broad ligament, and is extremely thin, and its fine connective-tissue fibres 
send prolongations into the longitudinal muscle-fibres of the appendix. Iz>ck- 
wood points out that the subperitoneal tissue of the meso-appendix and "the 
blood-vessels, nerves, and lymphatics which it contains are very intimately con- 
nected with the submucosa. This union takes place at certain large gaps in the 
muscular coats. These gaps serve for the transmission of blood-vessels, nerves, 
1 Journal of Anatomy and Physiology, 1891, vol. xxvi. 
2 A Contribution to the Pathology of the Vermiform Appendix. 
8 Lockwood on Appendicitis, THE CAECUM 
1305 
and lymphatics from the mesoappendix to the mucous coat. 1 hey are situated 
at the junction of the mesoappendix with the appendix."1 
The Longitudinal Muscular Layer is thin and irregularly distributed, and in certain 
regions may be excessively thin or actually absent, and between the fibres are the 
blood-vessels, nerves, and lymphatics passing from the subperitoneal tissue to the 
mucous coat. 
The Circular Fibres are much better developed than the longitudinal fibres, and, 
according to Iztckwood, the layer is 1 mm. thick. Large gaps are found here and 
there for the passage of vessels, lymphatics, and nerves to and from the meso- 
appendix and the mucous membrane, and a few vessels pierce the fibres at 
other points (Lockwood). 
The Submucous Coat varies greatly in thickness. It contains blood-vessels, 
nerves, and lymphatics, and some lymphoid follicles. 
The Mucous Membrane (Fig. 915) is covered by columnar 
epithelial cells and contains numerous solitary lymph- 
follicles, some glands of Lieberkuhn, surrounded by 
lymphoid tissue, blood-vessels, lymphatics, and nerves. 
The muscularis mucosae may be absent, may be scanty 
or may be distinct. The lymphoid follicles are visible to 
the naked eye (Fig. 915). Some of them are in the sub- 
mucosa, some of them chiefly in the mucosa, the bases of 
the latter, however, being in the submucosa. Lockwood 
estimates that an appendix three and a half inches in 
length contains from 150 to 200 follicles. 
Blood-vessels of the Caecum and Appendix (Figs. 914,916, 
932, and 933).-The ileo-colic artery in the ileo-colic angle 
gives off the anterior and posterior ileo-caecal arteries. The 
anterior ileo-caecal runs down over the front of the ileum 
and supplies the ileum, and sends off a terminal branch, 
the anterior caecal artery,which supplies the anterior surface 
of the caecum and of a portion of the ascending colon, and 
to the upper and lower margins of the ileo-caecal valve. It 
sends no branch to the appendix. The arteries of the ap- 
pendix- come from the posterior ileo-caecal artery, This 
vessel, after arising from the ileo-colic artery, passes back 
of the termination of the ileum and gives branches to the 
lower end of the ileum back of a portion of the ascending 
colon and to the lower margin of the ileo-caecal valve, 
where they anastomose with the valvular branches from the anterior ileo-caecal 
(Lockwood). From the posterior ileo-caecal comes the posterior caecal branch, 
which passes over the posterior and inner portion of the caecum near the base 
of the appendix and sends one or two branches to the appendix. The chief blood- 
supply of the appendix is the appendicular artery, which comes off the beginning 
of the posterior ileo-caecal or, occasionally, from the termination of the ileo-colic. 
If there is a distinct mesoappendix the largest branch of the artery passes along 
its free edge. If the mesoappendix is absent or rudimentary the artery usually 
lies upon the appendix from base to tip beneath the peritoneum. 
Lockwood points out that the appendicular artery as it enters the mesoappen- 
dix divides into three branches. The largest branch runs along the free edge, 
and from this the tip of the appendix obtains its blood-supply; "the other two 
reach the appendix at intervals of half an inch."2 When the branches reach 
the appendix they divide and pass around it in the subperitoneal coat and send 
Fig. 915.-The internal sur- 
face of the vermiform appen- 
dix. (Bonamy and Broca.) 
1 Appendicitis, its Pathology and Surgery. By Charles Barrett Lockwood. 2 Ibid. THE ORGANS OF DIGESTION 
1306 
branches through the muscular gaps to enter and pass through the submucous 
coat. 
In females there is occasionally some additional blood-supply through a branch 
of the ovarian artery in the appendiculo-ovarian ligament. 
The veins of the appendix are numerous, thin walled, and large. Veins from 
the submucous plexus pass through the muscular gaps and enter the subperi- 
ILEOCOLIC ARTERY 
AND VEIN 
ASCENDING 
COLON 
POSTERIOR 
ILEOCAECAL 
ARTERY 
AND VEIN 
ILIAC BRANCH 
APPENDICULAR 
ARTERY AND 
VEIN 
CAECUM 
Fig. 916.-Arteries and veins of the caecum and vermiform appendix seen from behind. (Poirier and Charpy.} 
toneal plexus. Veins from the subperitoneal plexus pass into veins in the meso- 
appendix which correspond to but do not really accompany the arteries (Lock- 
wood). Most of the veins of the mesoappendix pass to the posterior ileo-caecal 
vein, though some pass directly to the caecal vein. These veins are radicles of 
the portal system. 
EPITHELIUM 
GEAND 
CHORION 
■MUSCULAR LAYER 
Fig. 917.-Transverse section of the vermiform appendix of man. (Kolliker.) 
Lymphatic System of the Caecum and Appendix (Fig. 918).-Surrounding the base 
of each lymph-follicle in the submucous tissue of the appendix is a lymph-space, 
which Lockwood calls the follicular or basilar lymph-sinus. This sinus communi- 
cates with the lymphatics of the submucous coat, "which again communicate 
freely through the hiatus muscularis with those of the peritoneum and of the 
mesoappendix."1 The collecting trunks from the caecum and appendix follow the 
1 Appendicitis, its Pathology and Surgery. By Charles Barrett Lockwood. THE CAECUM 
1307 
blood-vessels (Fig. 918). The anterior collecting trunks of the caecum pass 
through several small glands in the anterior ileo-caecal fold, and terminate in 
ILEOCAECAL 
ANTERIOR 
LYMPHATICS 
OFCAECUM 
.ANTERIOR 
CAECAL 
GLAND OF 
APPENDIX 
APPENDICULAR 
EFFERENT 
LYMPHATICS 
Fig. 918.-Lymphatics of the caecum and appendix, anterior view. (Poirier and Charpy.) 
glands along the ileo-colic artery (Fig. 918). The posterior collecting trunks 
pass through some small glands and terminate in glands along the ileo-colic 
artery. The appendicular collecting trunks enter the mesoappendix. There are 
usually four of them, sometimes five. Some 
of them traverse a gland constantly present 
at the ileo-caecal angle (Clado). Another gland 
is constant. It is situated beneath the ileo- 
colic fossa (Lockwood and Rolleston). The 
ORIFICE OF' 
APPEN DIX 
Fig. 919.-Ileo-caecal valve of the circular type. 
(Poirier.) 
Fig. 920.-Vertical section through the caecum 
and ileo-caecal valve. (Gegenbauer.) 
editor subscribes to Lockwood's statement that in appendicitis there is often a 
chain of inflamed glands along the inner side of the ascending colon behind the 1308 
THE ORGANS OF DIGESTION 
ascending mesocolon. Hence this is one road taken by the lymphatics of the 
appendix. The others pass to the mesenteric glands. 
The Ileo-caecal Valve or the Valve of Bauhin {valvula coli) (Figs. 919, 920, 
921, and 922).-The lower end of the ileum terminates by opening into the inner 
and back part of the large intestine, at the point of junction of the caecum with the 
colon. The opening is guarded by a valve, consisting of two semilunar segments, 
an upper or colic segment {labium superius) and a lower or caecal segment {labium 
inferius), which project into the lumen of the large intestine. The upper one, 
nearly horizontal in direction, is attached by its convex border to the point of 
junction of the ileum with the colon; the lower segment, which is more concave 
and longer, is attached to the point of junction of the ileum with the caecum. 
At each end of the aperture the two segments of the valve coalesce, and are con- 
tinued as a narrow membranous ridge around the canal for a short distance. Each 
ridge is known as the retinaculum or frenulum of the valve (frenulum valvulae coli). 
The left or anterior end of the aperture is rounded; the right or posterior is narrow 
Fig. 921.-CeRcum and vermiform appendix. 1, 
ileum ; 2, orifice of valve ; 3, inferior segment ; 
4, superior segment ; 5, long muscular fibres from 
ileum ; 6, cul-de-sac of caecum ; 7, appendix ; 8, 
posterior taenia ; 9, internal taenia; 10, anterior 
taenia; 11, sacculus. (Sappey.) 
Fig. 922.- Ileo-caecal valve. 1, edge of caecum ; 2, 
orifice of valve ; 3, inferior segment ; 4, superior seg- 
ment ; 5 and 6, fraena ; 7, appendix; 8, mouth; 9, 
semilunar fold ; 10, posterior taenia ; 11, 12, 12, ante- 
rior taenia ; 13, internal taenia. (Sappey.) 
and pointed. In the formation of the valve the termination of the small intestine 
invaginates for a short distance into the lumen of the large intestine (Fig. 920), 
the invaginated portion of the wall of the small intestine uniting with a corre- 
sponding portion of the wall of the large intestine. 
Each segment of the valve is formed by a reduplication of the mucous mem- 
brane and of the circular muscular fibres of the intestine, the longitudinal fibres 
and peritoneum being continued uninterruptedly across from one portion of the 
intestine to the other. When the longitudinal fibres and peritoneum are divided 
or removed, the ileum may be drawn outward, and all traces of the valve will 
be lost, the ileum appearing to open into the large intestine by a funnel-shaped 
orifice of large size. 
The surface of each segment of the valve directed toward the ileum possesses 
villi, and presents the characteristic structure of the mucous membrane of the 
small intestine; while that turned toward the large intestine is destitute of villi, 
and marked with the orifices of the numerous tubular glands peculiar to the 
mucous membrane of the large intestine. These differences in structure continue THE COLON 
1309 
as far as the free margins of the valve. When the caecum is distended it is sup- 
posed that the margins of the opening are approximated so as to prevent reflux 
into the ileum. It is known, however, that a very large enema which distends 
the caecum and colon may in part enter the ileum, being driven there by waves 
of reversed peristalsis. The valve resists, but a certain amount of pressure over- 
comes it. Some believe that the so-called ileo-caecal valve is not a valve, but a 
distinct sphincter. This has been demonstrated to be true in cats and dogs, but 
lacks demonstration in man (p. 1323). 
The Colon 
The colon is divided into four parts-the ascending, transverse and descending 
colon, and the sigmoid flexure. 
The Ascending Colon (colon ascendens).-The ascending colon is smaller than 
the caecum, with which it is continuous. It passes upward, from its commence- 
ment at the frenula of the caecum, opposite the ileo-caecal valve, to the under sur- 
face of the right lobe of the liver, on the right of the gall-bladder, where it is lodged 
in a shallow depression on the liver, the impressio colica; here it bends abruptly 
inward to the left, forming the hepatic flexure (flexura coli dextro). It is retained 
in contact with the posterior wall of the abdomen by the peritoneum, which covers 
its anterior surface and sides, its posterior surface being connected by loose areolar 
tissue with the Quadratus lumborum and Transversalis muscles, and with the 
front of the lower and outer part of the right kidney (Fig. 923). Sometimes the 
peritoneum almost completely invests it, and forms a distinct but short meso- 
colon1 (p. 1259). It is in relation, in front, with the convolutions of the ileum and 
the abdominal parietes. 
The Transverse Colon (colon transversum) (Fig. 858).-The transverse colon, 
the longest part of the large intestine, passes transversely from right to left across 
the abdomen, opposite the confines of the epigastric and umbilical zones, into the 
left hypochondriac region, where it curves downward beneath the lower end of 
the spleen, forming the splenic flexure (flexura coli sinistra). In its course the 
transverse colon describes an arch, the concavity of which is directed backward 
toward the vertebral column and a little upward; hence the name transverse arch 
of the colon. This is the most movable part of the colon, being almost completely 
invested by peritoneum, and connected to the spine behind by a large and wide 
duplicature of that membrane, the transverse mesocolon (Fig. 863). The trans- 
verse colon is in relation, by its upper surface with the liver and gall-bladder, the 
great curvature of the stomach, and the lower end of the spleen; by its under sur- 
face, with the small intestines; by its anterior surface, with the anterior layers 
of the great omentum and the abdominal parietes; its posterior surface on the 
right side is in relation with the second portion of the duodenum, and on the left 
side is in contact with some of the convolutions of the jejunum and ileum. 
The Descending Colon (colon descendens).-The descending colon passes 
downward through the left hypochondriac and lumbar regions along the outer 
border of the left kidney. At the lower end of the kidney it turns inward toward 
the outer border of the Psoas muscle, along which it descends to the crest of the 
ilium, where it terminates in the sigmoid flexure. At its commencement it is con- 
nected with the Diaphragm by a fold of peritoneum, the phreno-colic ligament 
(see p. 1259). It is retained in position by the peritoneum, which covers its 
1 Treves states that after a careful examination of one hundred subjects, he found that in fifty-two there was 
neither an ascendinir nor a descending mesocolon. In twenty-two there was a descending mesocolon, but no 
trace of a corresponding fold on the other side. In fourteen subjects there was a mesocolon to both the ascend- 
ing and the descending segments of the bowel ; while in the remaining twelve there was an ascending mesocolon, 
but no corresponding fold on the left side. It follows, therefore, that in performing lumbar colostomy a meso- 
colon may be expected on the left side in 36 per cent, of all cases, and on the right in 26 per cent. (The Anat 
omy of the Intestinal Canal and Peritoneum in Man. 1885, p. 55.)-Ed. of 15th English edition. 1310 
THE ORGANS OF DIGESTION 
anterior surface and sides, its posterior surface being connected by areolar tissue 
with the outer border of the left kidney, and the Quadratus lumborum and 
Posterior 
lamella of 
lumbar fascia. 
Middle 
lamella of 
lumbar 
fascia. 
Anterior 
lamella of 
lumbar fascia. 
QUADRATUS LUMBORUM. 
LATISSIMUS 
DORSI. 
Ureter. 
Fig. 923.-Diagram of the relations of the large intestine and kidneys, from behind. 
Transversalis muscles (Fig. 863). It is smaller in calibre and more deeply placed 
than the ascending colon, and is more frequently covered with peritoneum on its 
posterior surface than the ascending colon (Treves). THE COLON 
1311 
The Sigmoid Flexure, Pelvic Colon or Sigmoid Colon {colon sigmoideum) 
(Figs. 924, 925, 926, and 927) is the narrowest part of the colon; it is situated in 
the left iliac fossa, commencing from the termina- 
tion of the descending colon, at the margin of the 
crest of the ilium, and then forming a loop, which 
varies in length and position, and which terminates 
in the rectum at the level of the attachment of the 
mesentery upon the front of the third sacral verte- 
bra. It passes downward about two inches parallel 
to the outer border of the Psoas muscle, then taking 
a transverse direction enters the cavity of the pelvis, 
crosses this cavity from left to right and a little, 
upward to the lower margin of the right iliac fossa; 
"from this point it passes downward, backward, 
and inward along the anterior surface of the sacrum 
to its junction with the rectum."1 It is surrounded 
with the peritoneum and is attached to the poste- 
DESCENDING COLON 
o 
RECTUM 
Fig. 924.-Sigmoid colon, front view 
Semidiagrammatic. (Testut.) 
Fig. 925.-Sigmoid colon and rectum, front view. The broken lines indicate the situation of the concealed part 
of the sigmoid colon. The small intestine is drawn away, and the anus is turned forward. (Testut.) 
rior abdominal wall by the mesosigmoid, a continuation of the mesocolon, but 
which greatly exceeds the latter in length, hence the sigmoid is the most mobile 
1 Tuttle, Diseases of the Anus, Rectum, and Pelvic Colon. 1312 
THE ORGANS OF DIGESTION 
portion of the large intestine. Tuttle divides the sigmoid into four portions. The 
first or vertical portion; the second or transverse portion; the third portion, which is a 
loop and is concave upward if the sigmoid occupies the pelvis, and is concave down- 
ward if it occupies the abdomen; the fourth portion, which is curved irregularly in 
the hollow of the sacrum, and which joins the rectum as often from the right as 
from the left. When the sigmoid is lifted up and to the right and the mesosigmoid 
is put slightly upon the stretch, an opening is seen at the parietal border of the left 
layer of the mesosigmoid. This opening leads into a cul-de-sac, the intersigmoid 
fossa. When the sigmoid is empty most of it falls into the recto-vesical or recto- 
vaginal space (Fig. 925). When distended it mounts up into the abdomen, reaching 
to or even above the umbilicus. The sigmoid flexure is in relation in front with 
the small intestine and abdominal parietes. The sigmoid mesocolon is attached 
to a line running downward and inward from the crest of the ilium, across the 
Psoas muscle (Fig. 863). 
The Rectum (Intestinum Rectum) (Figs. 924, 925, 926, 927, 928, 929). 
The rectum is the terminal part of the large intestine, and extends from the 
termination of the sigmoid flexure to the level of the semilunar valves of Mor- 
FOLDS OF 
Houston' 
URETHRA 
PROSTATE 
GLAN D 
TRANSVERSE 
PERIN^I 
MUSCLE 
EXTERNAL 
SPHINCTER 
MUSCLE 
Fig. 926.-Sagittal section in the median line of the pelvis. (Poirier and Charpy.) 
gagni. The sigmoid flexure terminates at the level of the attachment of the 
mesentery in front of the third sacral vertebra. This definition is practical and 
useful. It was suggested by Sir Frederick Treves. " It gives to the organ 
definite limits; it separates the mobile from the immobile portion of the gut; it 
marks the line where the course of the blood-supply changes; it indicates the THE RECTUM 
1313 
point where the three longitudinal muscular bands of the colon spread out and 
become more or less equally distributed around the gut; and, finally, it marks a 
point at which there is always a decided narrowing in calibre, indicating the 
juncture of the rectum with the pelvic colon."1 The old division added to this 
the so-called first part of the rectum, which we consider as part of the sigmoid colon. 
The rectum is divided into two portions, a superior and an inferior. The supe- 
rior or sacrococcygeal portion of the rectum (flexura sacralis) curves downward 
with the concavity forward and upward in front of the sacrum and coccyx, and 
is continued as far as the apex of the prostate gland, about an inch in front of 
the tip of the coccyx. The inferior or prostatic portion (flexura perinealis} begins 
at this point. The bowel is directed downward and backward, being convex in 
front, and terminates at the beginning of the anus at the level of the semilunar 
valves of Morgagni. The inferior or prostatic portion of the rectum is described 
by Symington as the anal canal. 
■UTERUS 
RECTAL FOLD 
.VESICO-UTERI NE 
CUL-DE-SAC 
CUL-DE-SAC. 
OF DOUGLAS 
RECTO- 
VAGINAL 
SEPTUM 
URETHRA 
Fig. 927.--Median sagittal section of the female pelvis. (Luschka.) 
Curves of the Rectum.-It will be seen, therefore, that the rectum presents two 
antero-posterior curves: the first, with its convexity backward, is due to the con- 
formation of the sacro-coccygeal column, and represents the arc of a circle, the 
centre of which is opposite the third sacral vertebra. The lower one has its 
convexity forward, and is angular. Its centre corresponds to a line drawn 
betwee'h the anterior parts of the ischial tuberosities. Two lateral curves are also 
described: the one to the right, opposite the junction of the third and fourth sacral 
vertebrae; the other to the left, opposite the sacro-coccygeal articulation. They 
are of little importance. 
The adult rectum as here described has a length of from four to six inches in men, 
and from three and five-eighths to five and one-eighth inches in women. Accord- 
ing to Tuttle the length of the rectum depends to some degree on the size of the 
1 A Treatise on Diseases of the Anus, Rectum, and Pelvic Colon. By James P. Tuttle. 1314 
THE ORGANS OF DIGESTION 
subject, and is somewhat greater in the old than in the young. The prostatic portion 
is the narrowest portion of the rectum. The widest part of the rectum is the ampulla 
recti just above the anal canal (Figs. 926 and 927). The prostatic portion has no 
peritoneal investment whatever and includes the lower two inches of the superior 
portion of the rectum. When the rectum is empty it is a mere slit, the anterior and 
posterior walls being in contact. When distended it is "irregularly cylindrical'' 
(Tuttle). At and above the level of the third sacral vertebra the gut is entirely sur- 
rounded by peritoneum, and there is a mesosigmoid. This is the mesorectum of 
those who describe the lower pelvic colon as the first part of the rectum. At the level 
of the third sacral vertebra the true rectum 
begins, and the true rectum has no meso- 
rectum. The rectum is covered in front and 
laterally by peritoneum at its upper part ; 
gradually the peritoneum leaves its sides, 
and about an inch above the prostate is re- 
flected from the anterior surface of the bowel 
on to the posterior wall of the bladder in 
the male, and the upper fifth of the posterior 
wall of the vagina in the female, forming 
the recto-vesical or recto-vaginal pouche (ex- 
cavatio rectovesicalis and excavatio rectoute- 
rina), as the case may be (Fig. 853). The 
balance of the rectum has no peritoneal cov- 
ering. The level at which the peritoneum 
leaves the anterior wall of the rectum to be 
reflected on to the viscus in front of it is of 
considerable importance from a surgical 
point of view, in connection with removal of the lower part of the rectum. It is 
higher in the male than in the female. In the former the height of the recto- 
vesical pouch is about three inches; that is to say, the height to which an ordinary 
index finger can reach from the anus. In the female the height of the recto- 
vaginal pouch is about two and a quarter inches from the anal orifice. 
The upper or sacro-coccygeal portion of the rectum is in relation, in front, in 
the male, with the recto-vesical pouch, the triangular portion of the base of the 
bladder, the vesiculae seminales, and vasa deferentia, and more anteriorly with 
the under surface of the prostate. In the female, with the posterior wall of the 
vagina below, and the recto-vaginal pouch above, in which are some convolutions 
of the small intestine (Fig. 927). To the sides below the peritoneal reflections, 
the rectum is surrounded by cellular tissue in which on each side lie the lateral 
sacral artery and the bifurcated hypogastric plexus. This portion of the rectum is 
separated from the sacrum and coccyx by an interval, the retro-rectal space, which 
is filled with cellular tissue. The superior portion of the distended rectum is in con- 
tact posteriorly and on each side with the sacral plexus, ganglia of the sympathetic, 
and the fascial origin of the pyramidalis muscle (Tuttle). The lower or prostatic 
portion in men is in relation anteriorly with the prostate gland and the membranous 
urethra; in women with the posterior wall of the vagina. The lower end of the 
rectum takes a backward turn, and the uro-genital organs turn forward; the inter- 
vening space is called the perineum. In the female, the fibro-fatty and muscular 
tissue which occupies this space is called the perineal body. The prostatic portion 
of the rectum is invested by the Internal sphincter, supported by the Levatores 
ani muscles, and surrounded at its termination by the External sphincter; in the 
empty condition it presents the appearance of a longitudinal slit. Posteriorly 
the lower part of the rectum is in contact with cellular tissue, which separates it 
from the coccygeal gland and the coccyx. 
Fig. 928.-Diagram of rectum, showing Hous- 
ton's valves in the interior. (Cunningham.) THE RECTUM 
1315 
Supports of the Rectum.-The rectum as it has been described in these pages is a 
fixed tube. The upper portion of the rectum is supported by "the inferior mesen- 
teric arteries and the fibrous sheaths which surround them'' (Tuttle); by the peri- 
toneal folds which attach it to the sacrum; and by the peritoneal folds which pass 
in front to the bladder {plicae rectovesicales), or to the uterus {plicae rectouterinae), 
and laterally to the pelvis. The middle of the rectum receives some support 
from the lateral sacral arteries and their fibrous sheaths. The lower portion of the 
rectum is supported by the Levator ani, External sphincter, and Recto-coccygeus 
muscles. 
Blood-vessels and Lymphatics of Rectum.-See pp. 1320 and 1322. 
Nerves of Rectum.-See p. 1322. 
Structure of Rectum.-See p. 1316. 
RECTAL VALVES 
Fig. 929.-The anal canal and lower part of the rectum in the foetus. A, aged four to five months ; B, six 
months ; C, nine months. In each the anal canal is distinctly marked off from the rectum proper ; the columns 
of Morgagni and the rectal valves are distinct. (Cunningham.) 
AB C 
The Common Anal Canal (pars analis recti') (Figs. 929 and 930).-The anal 
canal is the third portion of the rectum of the older descriptions. It begins 
where the true rectum ends. This canal is the portion of the intestinal tract which 
LONGITUDINAL 
FIBRES OF 
RECTUM 
RUGXE OF 
- MUCOUS 
MEMBRANE 
COLUMNS OF 
MORGAGNI 
PART OF 
LEVATOR AN. 
INTERNAL 
SPHINCTER 
ANAL CANAL 
ANAL VALVES 
Fig. 930 -The interior of the anal canal and lower part of the rectum, showing the columns of Morgagni and 
the anal valves between their lower ends. The columns were more numerous in the specimen than usual. 
(Cunningham.) 
is below the distribution of genuine mucous membrane, and is just posterior to 
the middle of a line drawn from one tuberosity to the other. It lies between the 
true skin and the upper borders of the semilunar valves of Morgagni. When at 
rest it is a mere slit placed antero-posteriorly. The external opening of the anal 
canal is the anus. The skin about the anus is pigmented, is thrown into radi- 
ating folds by the contraction of the External sphincter muscle, and contains 
hairs, sebaceous glands, and sudoriparous glands (glandulae circumanales). 
Ascending into the canal, it alters its character and becomes muco-cutaneous. THE ORGANS OF DIGESTION 
1316 
and true mucous membrane appears at the rectum proper. Back of the anus is 
a median cutaneous fold passing posterior to the coccyx and called the anal raphe. 
In front of the anus is a median fold which, in the female, passes forward and 
merges with the labia major and in the male continues into the raphe of the 
scrotum. This is called the perineal raphd. The length of the anal canal is three- 
quarters to one inch. "Its circumference varies from 3 cm. (one and three- 
sixteenths inches) in normal condition to 15 cm. (five and five-sixteenths inches) 
in disease, following injury or vicious practices. The average anus will admit a 
cylinder of 65 mm. in circumference without rupturing the mucous membrane."1 
Relations of the Anal Canal.-It is surrounded by the external and internal 
sphincter muscles, and above by the Levatores ani. To each side is the ischio- 
rectal fossa containing fat. Between the anal canal and the coccyx is a collec- 
tion of muscular fibres and connective tissue, the ano-coccygeal body of Symington. 
In front, in the male, is the bulb of the urethra and the base of the triangular 
ligament ; in the female, is the perineal body, which separates the anus from 
the vagina. There are three layers in the wall of the anal canal: 
1. The muco-cutaneous layer, which contains glands, blood-vessels, and numer- 
erous nerve-endings. The lower portion is covered with pavement-epithelium, 
but gradually there is a transition, and at the beginning of the rectum proper the 
epithelium is entirely columnar. The valves of Morgagni, the anal valves or the semi- 
lunar valves (Figs. 933 and 931) are in the upper portion of the anal canal between 
the lower ends of the columns of Morgagni (Figs. 930 and 931). Above the valves 
the canal is lined by transitional mucous membrane, below them by modified skin. 
The ano-rectal line is not straight, but is irregularly dentated by trivial eleva- 
tions, each of which is papilliform at its summit. According to Tuttle, these 
elevations number from five to eight. About one-fifth of an inch below the ano- 
rectal line is the depression known as Hilton's white line (annulus haemorrhoidalis) 
(Fig. 931). This line is somewhat indistinct to sight, but can always be felt with 
the finger. It marks the junction of the External with the Internal sphincter. 
Above Hilton's line are some mucous crypts and also dilatations produced by the 
internal haemorrhoidal plexus of veins (Fig. 931). 
2. The fibro-cellular layer is beneath the mucous membrane. Above Hilton's 
line it is composed of cellular tissue; below it is a thin fascia-like layer which joins 
the superficial fascia. 
The anal canal is surrounded by longitudinal fibres from the rectum, fibres from 
the levator ani, the lower portion of the Internal sphincter, and particularly by 
the External sphincter. 
Blood-vessels, Lymphatics, and Nerves of Anus.-See pp. 1321 and 1322. 
Structure of Large Intestine (including the Rectum and Anal Canal).-The 
large intestine has four coats-serous, muscular, areolar or submucous and mucous. 
The Serous Coat (tunica serosa).-The serous coat is derived from the peritoneum, 
and invests the different portions of the large intestine to a variable extent. The 
caecum is completely covered by the serous membrane, except in a small percent- 
age of cases (5 or 6 per cent.), where a small portion of the upper end of the pos- 
terior surface is uncovered. The ascending and descending colon are usually 
covered only in front and at the sides; a variable amount of the posterior surface 
is uncovered. The transverse colon is almost completely invested, the parts corre- 
sponding to the attachment of the great omentum and transverse mesocolon being 
alone excepted. The sigmoid flexure is completely surrounded, except along the 
line to which the sigmoid mesocolon is attached. The upper two-thirds of the 
rectum is covered in front and laterally by the peritoneum, but not posteriorly, 
between the two posterior folds of peritoneum, the so-called mesorectum; later 
1 Diseases of the Anus, Rectum, and Pelvic Colon. By James P. Tuttle. THE RECTUM 
1317 
it is covered only on its anterior surface; and the lower portion is entirely 
devoid of any serous covering. In the course of the colon the peritoneal coat is 
thrown into a number of small pouches filled with fat, called appendices epiploicae. 
They are chiefly appended to the transverse colon, and are particularly numerous 
along the anterior band. 
The Muscular Coat (tunica muscularis).-The muscular coat consists of an 
external longitudinal and an internal circular layer of muscular fibres. 
The Longitudinal Fibres, although found to a certain extent all around the 
intestine, do not form a uniform layer over the whole surface of the large 
intestine. In the caecum and colon they are especially collected into three flat 
longitudinal bands or taeniae (taeniae coli) (Figs. 910 and 911), each being about 
half an inch in width. These bands commence at the base of the vermiform 
appendix, which structure is surrounded by a uniform layer of longitudinal 
muscular fibres. The bands pass from the base of the appendix to the rectum. 
At this point they broaden, fuse, and surround the rectum. On the ascend- 
ing, descending, and sigmoid colon the mesocolic band (taenia mesocolica) is 
posterior and internal; the omental band (taenia omentalis) is posterior and 
external; the free band (taenia libera) is anterior. On the transverse colon the 
taenia libera is inferior; the taenia mesocolica is posterior; the taenia omentalis 
is anterior and superior. These bands are one-sixth shorter than the other coats 
of the intestine to which they are applied, and serve to produce the sacculi (Fig. 
911), which are characteristic of the caecum and colon; accordingly, when they 
are dissected off, the tube can be lengthened, and its sacculated character becomes 
lost. The sacculations are called haustra coli. There are three rows of the sac- 
culations separated from each other by the longitudinal bands. These pouches 
are also subdivided by transverse furrows which correspond to concave folds of 
mucous membrane, called semilunar folds (plicae semilunares coli). In the sig- 
moid flexure the longitudinal fibres become more scattered; but upon its lower 
part, and around the rectum, they spread out and form a layer which completely 
encircles this portion of the gut, but is thicker on the anterior and posterior 
surfaces, where two accentuations exist, than on the lateral surfaces. In the 
rectum the external fibres of the longitudinal layer descend and are inserted into 
the fascia covering the Levator ani muscle. The middle fibres are mingled with 
descending fibres of the Levator ani and terminate by attachment to the rectal 
wall. 'I'lie internal fibres descend between the External and Internal sphincter 
muscles and are inserted into the superficial fascia around the anal margin. 
The lower part of the rectum is surrounded by the Levator ani muscle (p. 451). 
In addition to the muscular fibres of the bowels, two bands of plain muscular 
tissue are to be noted. They arise from the front of the second and third coccy- 
geal vertebrae, and pass downward and forward to blend with the longitudinal 
muscular fibres on the posterior wall of the rectum. Each is known as the recto- 
coccygeal muscle (m. rectococcygeus). 
The Circular Fibres form a thin layer over the caecum and colon, being especially 
accumulated in the intervals between the sacculi. In the rectum the circular fibres 
constitute a thick coat at some portions of the circumference and a thinner coat 
at others. The circular fibres are thickened at every flexure. The thickenings 
only partly surround the gut, and hence are not to be considered as additional 
sphincters. 'Puttie calls them the semicircular muscles of the rectum. These semi- 
circular muscles are opposite the insertion of Houston's valves. At the lower end 
of the rectum the circular fibres become very numerous and constitute the Internal 
sphincter muscle (m. sphincter ani internus) (Fig. 930). 'Puttie describes it as fol- 
lows: "This muscle, composed of an aggregation of circular fibres, begins about 
4 cm. above the anal margin, and gradually increases in thickness until it reaches 
the ano-rectal line, after which it thins out again and disappears about the middle THE ORGANS OF DIGESTION 
1318 
of the anal canal. Its width from above downward averages 1 to 3 cm. (three-fifths 
of an inch to one and one-fifth inches). Its thickness is so variable that no accurate 
measurement can be given. Its lower fibres are below and within the grasp of the 
External sphincter, from which it is separated by a narrow zone of connective 
tissue. A depressed zone, not always perceptible to the eye, but appreciable 
by digital touch, marks the line of division between these two muscles."1 The 
Internal sphincter is an involuntary muscle. The external sphincter muscle is 
not a portion of the wall of the bowel. It is described on pages 450 and 451. 
The Areolar Coat or Submucous Coat (tela submucosa).-The areolar or sub- 
mucous coat connects the muscular and mucous layers closely together. This coat 
is thicker, looser, and more elastic in the rectum than elsewhere. In this coat are 
the blood-vessels, nerves, and lymphatics. 
The Mucous Membrane (tunica mucosa).-The mucous membrane, in the caecum 
and colon, is pale, smooth, destitute of villi, and raised into numerous crescentic 
folds which correspond to the intervals between the sacculi. In the rectum it is 
thicker, of a darker color, more vascular, and connected loosely to the muscular 
coat, as in the oesophagus. 
The rectum contains certain horizontal folds. Most of them disappear when 
the gut is distended, but some of them do not disappear, but remain as distinct 
MUSCULAR WALL 
OF RECTUM 
MUCOUS. 
MEMBRANE 
DILATATION 
* OF VEINS' 
INTERNAL HEMOR- 
RHOIDAL PLEXUS 
COLUMNS O F_ 
MORGAGNI 
VALVE OF 
MORGAGNI 
DILATATION 
OF VEIN 
COMMUNICATION BE- 
TWEEN INTERNALAND 
EXTERNAL HEMOR- 
HILTON'S 
WHITE LINE 
RHOIDAL PLEXUS 
INTERNAL 
SPHINCTER 
EXTERNAL 
SPHINCTER 
SKIN 
LONGITUDINAL 
TENDINOUS FIBRES 
SUBCUTANEOUS 
CELLULAR TISSUE 
Fig. 931.-Inner wall of the lower end of the rectum and anus. On the right the mucous membrane has 
been removed to show the dilatation of the veins and how they pass through the muscular wall to anastomose 
with the external haemorrhoidal plexus. (Luschka.) 
folds with free crescentic edges. These permanent folds were first described by 
Houston, of Dublin, and are known as rectal valves or Houston's valves (plicae 
transversales recti') (Figs. 928 and 929). Each fold surrounds more than one- 
third of the gut, and is composed of mucous membrane, submucous tissue, and 
a layer from the circular muscular layer of the gut. There may be three, four, or 
five of these folds. Three of them are constant. One is on the right rectal wall, 
about the point of peritoneal reflection; another is on the left side, about one 
inch above the margin of the anal canal. A third is on the rectal wall, either 
toward the right or left, at the point where the rectum joins the front of the 
sigmoid. These shelf-like valves are not perfectly flat, for on the superior surface 
of each is a depression. 
The borders of a valve are thinner than its base and are very flexible. These 
valves support the mass of feces as it descends, and give to it a rotary motion 
1 Diseases of the Anus, Rectum, and Pelvic Colon. By James P. Tuttle. THE RECTUM 
1319 
(Tuttle). In the lower end of the rectum the mucous membrane forms longi- 
tudinal folds known as the columns of Morgagni or the rectal columns (columnae 
rectales [Morgagni]) (Figs. 930 and 931). There are from five to ten of these 
folds, each of which is about one-half an inch long, and they contain longitudinal 
muscle-fibres. They are most prominent when the sphincter contracts. The base 
of each column helps to form the upper margin of the anal canal. The outer angle 
of each column below passes into a semilunar valve. The grooves between the 
columns are shallow above and deeper below, and end in the semilunar valves. 
The semilunar valves, valves of Morgagni or anal valves (Figs. 930 and 931) are folds 
which stretch from the base of one column to another, and form the anal pockets 
or crypts of Morgagni (sinus rectales'). These pockets are about 5 mm. in depth. 
They are most marked posteriorly (Ball), but none exists in either the anterior 
or posterior commissure (Tuttle). Below the sinuses is the white line of Hilton 
(annulus haemorrhoidalis) (Fig. 931), which reaches to the region where hair and 
sebaceous glands appear. 
A- 
1 
D 
, B 
6 
F 
C 
E 
H 
2, 
3 
Fig. 932.-The arterial circulation in the dorsal posterior surface of the caecum and appendix. A, ileo-colic 
artery; B and F, posterior caecal artery; C, appendicular artery; E, appendicular artery for free end; H, artery 
for basal end of appendix; 1, ascending or right colon; 2, external sacculus of the caecum; 3, appendix; 6, ileum; 
D, arteries on the dorsal surface of the ileum. (Byron Robinson.) 
As in the small intestine, the mucous membrane consists of a muscular layer, the 
muscularis mucosae (Fig. 935); of a quantity of retiform tissue in which the vessels 
ramify; of a basement-membrane and epithelium, which is of the columnar variety, 
and exactly resembles the epithelium found in the small intestine. In the rectum 
the epithelial cells are columnar; at the lower end of the tube, however, they begin 
to change into stratified polyhedrons and prisms. The mucous membrane of the 
large intestine presents for examination simple follicles and solitary glands. 
The Simple Follicles, Intestinal Glands, Crypts or Glands of Lieberkuhn (glandulae 
imestinales [Lieberkuhni]) (Fig. 935) are minute tubular prolongations of the 
mucous membrane arranged perpendicularly, side by side, over its entire sur- 
face; they are longer, more numerous, and are placed in much closer apposition 
than those of the small intestine; and they open by minute rounded orifices upon 
the surface, giving it a cribriform appearance. THE ORGANS OF DIGESTION 
1320 
The Solitary Glands {noduli lymphatici solitarii) (Fig. 935) in the large intes- 
tine are most abundant in the caecum and vermiform appendix, but are irregu- 
larly scattered also over the rest of the intestine. They are similar to those of the 
small intestine. 
Vessels of the Large Intestine.-The arteries supplying the large intestine give 
off large branches, which ramify between the muscular coats supplying them, 
and, after dividing into small vessels in the submucous tissue, pass to the 
mucous membrane. The caecum, the appendix, and the ileo-caecal valve are sup- 
plied by the branches from the anastomotic loops between the right colic and ileo- 
Fig. 933.-The arterial blood-supply of the anterior (ventral) surface of the caecum and appendix. A, ileo- 
colic artery; B, caecal-appendicular artery; D, anterior caecal artery; F and G, appendicular artery. Note that 
the caecal and appendicular arteries anastomose by fine capillaries, both ventral and dorsally; C, iliac artery; 
1, right colon; 2, external sacculus of caecum (to right of taenium coli); 3, appendix; 4, Iliac, and 5, Psoas muscles. 
(Byron Robinson.) 
colic branches of the superior mesenteric artery (Figs. 932 and 933). In males the 
sole blood-supply of the appendix is by the appendicular artery from the posterior 
ileo-caecal branch of the ileo-caecal artery (Fig. 933). In the female the appendix 
occasionally receives an additional vessel along the appendiculo-ovarian ligament 
from the ovarian artery. The ascending colon is supplied by the right colic, and the 
transverse colon by the middle colic branch of the superior mesenteric. The 
descending colon is supplied by the left colic branch of the inferior mesenteric, 
and the sigmoid flexure by the sigmoid branches of the inferior mesenteric. The 
rectum (Fig. 934) is supplied mainly by the superior haemorrhoidal branch of the 
inferior mesenteric, but also at its lower end by the middle haemorrhoidal from 
the internal iliac, and the inferior haemorrhoidal from the pudic artery. The supe- THE RECTUM 
1321 
nor haemorrhoidal, the continuation of the superior mesenteric, divides into two 
branches, which run down either side of the rectum to within about five inches 
of the anus; they here split up into about six branches, which pierce the 
muscular coat and descend between it and the mucous membrane in a longi- 
tudinal direction, parallel with each other as far as the Internal sphincter, where 
they anastomose with the other haemorrhoidal arteries and form a series of loops 
around the anus. 'The veins of the large intestine correspond to the arteries and 
join the superior and inferior mesenteric veins which join the portal vein. The veins 
of the rectum (Fig. 934) commence in a plexus of vessels which surrounds the lower 
extremity of the intestinal canal. In the vessels forming this plexus are small 
saccular dilatations just within the margin of the anus (Figs. 931 and 934); 
from it about six vessels of considerable size are given off. These ascend between 
the muscular and mucous 
coats for about five inches, 
running parallel to each 
other ; they then pierce the 
muscular coat, and, by their 
union, form a single trunk, 
the superior haemorrhoidal 
vein, which empties into the 
inferior mesenteric branch of 
the portal vein. This arrange- 
ment is termed the haemor- 
rhoidal plexus (Fig. 473); it 
communicates with the tribu- 
taries of the middle and infe- 
rior haemorrhoidal veins at its 
commencement, and thus a 
communication is established 
between the systemic and 
portal circulations. The in- 
ferior haemorrhoidal veins 
empty into the internal pudic 
veins, and the middle haemor- 
rhoidal veins empty into the 
internal iliac veins. 
The Lymphatics of the Large 
Intestine. - The lymphatics 
of the large intestine begin 
in the mucous membrane and 
form an extensive plexus in 
the submucosa. There are 
also lymphatics more deeply 
seated, beneath the simple 
follicles. Those from the 
ascending colon and trans- 
verse colon open into the 
glands within the mesocolon 
and behind the colon (meso- 
colic glands), from which 
glands trunks pass to the superior mesenteric glands. The lymphatics from the 
transverse colon join with lymph-vessels of the great omentum, and hence com- 
municate with the lymphatics of the greater curvature of the stomach. The lymph 
from the descending colon, from the sigmoid and from the pelvic colon passes to 
SUPERIOR 
HEMORRHOIDAL 
VEIN 
SUPERIOR 
• hemorrhoidal 
ARTERY 
MIDDLE 
HEMORRHOIDAL 
ARTERY 
INFERIOR 
HEMORRHOIDAL 
ARTERY 
Fig. 934.-The blood-vessels of the rectum and anus, showing the 
distribution and anastomosis on the posterior surface near the termi- 
nation of the gut. (Poirier and Charpy.) 1322 
THE ORGANS OF DIGESTION 
the glands along the inferior mesenteric artery. The lymphatics of the rectum 
pass first to the rectal glands, which lie on the muscular coat of the rectum, next to 
the glands which lie back of the rectum along the superior haemorrhoidal artery, 
and finally to the sacral glands. Lymphatics from the skin of the anus pass 
with the lymphatics of the skin to the superficial inguinal glands. Lymphatics 
from the anus between the skin margin and Hilton's white line pass to the hypo- 
gastric glands. 
The Nerves of the Anus and Rectum.-The nerves of the anus and rectum are 
derived from both the sympathetic and cerebro-spinal system. The chief supply 
of the rectum is from the mesenteric, sacral, and hypogastric plexuses of the sympa- 
thetic. It also obtains small branches from the third, fourth, and fifth sacral nerves. 
The lower part of the rectum is much more sensitive than the upper part, 
'fhe muscles of the anus and rectum are supplied "from the intricate plexuses 
formed by the second, third, fourth, and fifth sacral nerves" (Tuttle). The 
External sphincter is supplied by nerves which contain motor, sensory, and 
Surface of mucous membrane, 
with openings of Lieberkuhn's 
follicles. 
Lieberkuhn's follicles. 
Muscularis mucosae (two layers). 
Submucous connective tissue. 
Solitary gland. 
Fig. 935.-Minute structure of large intestine. 
sympathetic fibres. These nerves come from three sources. "Two filaments 
from the branches formed by the third, fourth, and fifth sacral nerves extend 
transversely across the ischio-rectal fossa and distribute themselves to the middle 
portion of the muscle and to the peri-anal cutaneous surface; a filament which 
comes off from the internal pudic just before its division into terminal branches 
supplies the anterior portion of the muscle, and is called the anterior sphincterian 
nerve; while a filament coming off from the fifth and sixth sacral nerves passes 
down into the hollow of the sacrum, between the levator ani muscle and the recto- 
coccygeus ligament, and finally reaches the posterior superficial surface of the 
External sphincter."1 'The spinal centre for the nerves of the anus and rectum is 
opposite the first lumbar vertebra, and is in practically the same region as the 
centre for the genito-urinary organs. 
Movements and Innervation of the Intestines. 
Movements.-As the small intestine is devoid of any sphincter arrangement peristalsis cannot 
mix the food as it does in the pyloric portion of the stomach. The process by which the food is 
mixed with the secretions and is brought against the intestinal wall for absorption is called 
by Cannon "rhythmic segmentation." Rhythmic motions, according to Cannon, "mix the 
1 Diseases of the Anus, Rectum, and Pelvic Colon. By James P. Tuttle MOVEMENTS AND INNERVATION OF THE INTESTINES 
1323 
food and expose it to the mucosa without advancing it appreciately along the canal."1 In this 
process constrictions occur in the circular fibres, with the result that a collection of stationary 
food is divided into a number of segments. In the middle of each segment constrictions appear 
and the earlier constrictions relax. Then the later constrictions relax and the earlier reappear 
and so on until the food is thoroughly mixed with digestive secretions. Finally the food is 
driven on by peristalsis coming again to rest and being again subjected to "rhythmic segmenta- 
tion."2 Cannon says that in the duodenum "rhythmic segmentation" lasts for several minutes, 
but in other parts of the intestine it may continue for half an hour or more, the food which is 
being subjected to it scarcely moving along the canal. Cannon infers that in man there are 
from seven to eight segmentations per minute in a given area. It is probable that there is a 
sphincter action at the ileo-caecal opening. 
Cannon divides the large intestine into two parts: a distal part, in which the material is hard 
and lumpy and is "advanced by rings of tonic contraction," and a proximal part, in which 
the material is soft. In this part "the common movements are waves of constriction running 
backward toward the caecum."3 The resistance of the valve or sphincter enables reversed 
peristalsis or antiperistalsis to mix the food. When more food enters from the small intestine, 
antiperistalsis ceases, tonic contraction of the caecum and proximal portion of the colon occurs, 
some of the food is merged into the transverse colon, and anti peristalsis again begins to act 
on what remains.4 The above facts have been observed in animals and are probably true in 
man. 
Innervation.-The pneumogastric fibres of the small intestine seem to excite contraction of 
the circular fibres after a brief preliminary period of inhibition? Some observers maintain 
that the splanchnic fibres are inhibitory, but others claim that they are also motor. The local 
reflex of the small intestine is in Auerbach's plexus. Cannon quotes Bayliss and Starling to 
the effect that the pelvic visceral nerves to the large intestine, "arising like the vagus from the 
central nervous system, are augmentary nerves, whereas the supply from the sympathetic sys- 
tem is purely inhibitory in its action."6 It is further contended that the pelvic visceral nerves 
are distributed to the distal colon only. "The region of antiperistalsis does not, therefore, 
receive motor impulses from the pelvic nerves."7 
Surface Form.-The coils of the small intestine occupy the front of the abdomen below the 
transverse colon, and are covered more or less completely by the great omentum. For the most 
part the coils of the jejunum occupy the left side of the abdominal cavity-i. e., the left lumbar 
and inguinal regions and the left half of the umbilical region-whilst the coils of the ileum are 
situated to the right, in the right lumbar and inguinal regions, in the right half of the umbilical 
region, and also in the hypogastric region. The caecum is situated in the right inguinal region. 
Its position varies slightly, but the mid-point of a line drawn from the anterior superior spinous 
process of the ilium to the symphysis pubis will about mark the middle of its lower border. It is 
comparatively superficial. From it the ascending colon passes upward through the right lumbar 
and hypochondriac regions, and becomes more deeply situated as it ascends to the hepatic flexure, 
which is deeply placed under cover of the liver. The transverse colon crosses the belly trans- 
versely on the confines of the umbilical and epigastric regions, its lower border being on a level 
slightly above the umbilicus, its upper border just below the greater curvature of the stomach. 
The splenic flexure of the colon is situated behind the stomach in the left hypochondrium, and 
is on a higher level than the hepatic flexure. The descending colon is deeply seated, passing 
down through the left hypochondriac and lumbar regions to the sigmoid flexure, which is situ- 
ated in the left inguinal region, and which can be felt in thin persons, with relaxed abdominal 
walls, rolling under the fingers when empty, and when distended forming a distinct bulge. The 
position of the base of the vermiform appendix is indicated by a point two inches from the 
anterior superior spinous process of the ilium, on a line drawn from this process to the umbilicus. 
This is known as McBurney's point. Another mode of defining the position of the base of the 
appendix is to drdw a line between the anterior superior spines of the ilia and marking the point 
where this line intersects the right semilunar line. 
Upon introducing the finger into the rectum, the membranous portion of the urethra can 
be felt, if an instrument has been introduced into the bladder, exactly in the middle line; behind 
this the prostate gland can be recognized by its shape and hardness and any enlargement detected; 
behind the prostate the fluctuating wall of the bladder when full can be felt, and if thought 
desirable it can be tapped in this situation; on either side and behind the prostate the vesiculae 
seminales can be readily felt, especially if enlarged by tuberculous disease. Behind, the coccyx 
is to be felt, and on the mucous membrane one or two of Houston's folds. The ischio-rectal 
fossae can be explored on either side, with a view to ascertaining the presence of deep-seated 
collections of pus. Finally, it will be noted that the finger is firmly gripped by the sphincter for 
about an inch up the bowel. By gradual dilatation of the sphincter, the whole hand can be 
' Medical News, May 20, 1905. 2 Walter B. Cannon, in Medical News, May 20, 1905. 
3 Medical News, May 20, 1905. 4 Ibid. 
5 Bayliss and Starling, Journal of Physiology, 1899. 
6 Medical News, May 20, 1905. Walter B. Cannon, Medical News, May 20, 1905. 1324 
THE ORGANS OF DIGESTION 
introduced into the rectum so as to reach the descending colon. This method of exploration is 
not at the present day employed for diagnostic purposes. 
Surgical Anatomy.-The small intestine is much exposed to injury, but, in consequence 
of its elasticity and the ease with which one fold glides over another, it is not so frequently rup- 
tured as would otherwise be the case. Any part of the small intestine may be ruptured, but 
probably the most common situation is the transverse duodenum, on account of its being more 
fixed than other portions of the bowel, and because it is situated in front of the bodies of the 
vertebrae, so that if this portion of the intestine is struck a sharp blow, as from the kick of a 
horse, it is unable to glide out of the way, but is compressed against the bone and lacerated. 
Wounds of the intestine sometimes occur. If the wound is a small puncture, under, it is said, 
three lines in length, there may be no extravasation of the contents of the bowel. The mucous 
membrane becomes everted and perhaps plugs the little opening. The bowels, therefore, may be 
punctured with a fine capillary trocar, in cases of excessive distention of the intestine with gas, with- 
out much danger of extravasation. A longitudinal wound gapes more than a transverse wound, 
owing to the greater thickness of the circular muscular coat. In closing a wound of the intestine, 
use Lembert's inversion sutures, which bring the peritoneal surfaces in contact. Halsted showed 
us that these sutures must include the tough submucous coat. The portions of intestine which lie 
in the pelvis are inflamed in pelvic peritonitis and become embedded in adhesions. The portions 
of intestine which may be present are the termination of the ileum, the portion of small intestine 
with the largest mesentery (Treves), the rectum, and the pelvic colon. The small intestine, and 
most frequently the ileum, may become strangulated by internal bands, or through apertures, 
normal or abnormal. The bands may be formed in several different ways: they may be old peri- 
toneal adhesions from previous attacks of peritonitis; or adherent omentum from the same 
cause; or the band may be formed by Meckel's diverticulum, which has contracted adhesions at 
its distal extremity; or the band may be the result of the abnormal attachment of some normal 
structure, as the adhesion of two appendices epiploicae, or an adherent vermiform appendix or 
Fallopian tube. Intussusception or invagination of the small intestine may take place in any part 
of the jejunum and ileum, but the most frequent situation is at the ileo-caecal valve, the valve 
forming the apex of the entering tube. This form may attain great size, and it is not uncom- 
mon in these cases to find the valve projecting from the anus. Stricture, the impaction of 
foreign bodies, and twisting of the gut (volvulus') may lead to intestinal obstruction. Volvulus is 
most common in the sigmoid flexure. Meckel's diverticulum may itself become twisted and 
strangulated. 
Resection of a portion of the intestine may be required in cases of gangrenous gut; in cases 
of intussusception; for the removal of new growth in the bowel; in dealing with artificial anus; 
and in cases of rupture. The operation is termed enterectomy, and is performed as follows: the 
abdomen having been opened and the amount of bowel requiring removal having been deter- 
mined upon, the gut must be clamped on either side of this portion in order to prevent the escape 
of any of the contents of the bowel during the operation. The portion of bowel is then separated 
above and below by means of scissors. If the portion removed is small, it may be simply removed 
from the mesentery at its attachment and the bleeding vessels tied; but if it is large, it will be 
necessary to remove also a triangular piece of the mesentery, and having secured the vessels, 
suture the cut edges of this structure together. The surgeon then proceeds to unite the cut 
ends of the bowel together. He may do it by the operation termed end-to-end anastomosis. 
There are many ways of doing this, which may be divided into two classes: one, where the anas- 
tomosis is made by means of some mechanical appliance, such as Murphy's button, or one of 
the forms of decalcified bone bobbins; and the other, where the operation is performed by 
simply suturing the ends of the bowel in such a manner that the peritoneum covering the free 
divided ends of the bowel is brought into contact, so that speedy union may ensue. 
In some cases after resection each open end of the gut is closed, the side of the terminal portion 
is sutured to the side of the initial portion, a fistula is made in each, and the suturing is com- 
pleted so as to cause the two fistulae to correspond. A permanent side-to-side opening is 
thus made. Lateral anastomosis without resection may be practised between two pieces of 
intestine, in order to side-track an intervening portion, which is the seat of malignant disease or 
of an artificial anus. Complete exclusion of a portion of intestine is performed for irremovable 
tumors or persistent faecal fistulae of the large intestine. The intestine is cut through above and 
below the diseased area and the ends of the healthy gut are united to each other, or the larger 
end is closed, an opening is made into the side of the larger end and the smaller end is implanted 
in it (lateral implantation). The two ends of the excluded portion are fastened to the skin and 
are left open. 
In ascites resulting from cirrhosis of the liver benefit occasionally follows the performance of 
Talma's operation (epiplopexy). The abdomen is opened and the omentum is sutured to the 
anterior abdominal wall or in the abdominal wound in the hope of establishing a more, free 
communication between the portal and systemic circulations, thus lowering portal pressure. 
External hernia is considered on page 1325. 
By the term internal hernia, we mean hernia into the foramen of Winslow, into the retro- MOVEMENTS AND INNERVATION OE THE INTESTINES 
1325 
duodenal fossa, into the retro-caecal fossa, or into the intersigmoid fossa. Such a hernia produces 
the symptoms of acute strangulation of the intestine. 
In typhoid jever there is ulceration of Peyer's patches. One of these ulcers may perforate. 
The only chance for life is immediate laparotomy and closure of the perforation. This saves 
one-fifth, or possibly one-third, of the cases. The incision is made to expose the lower ileum, as 
in the vast majority of cases the perforation is in this portion of the gut. 
Ulcer oj the duodenum is more common than used to be thought. The portion of the duo- 
denum between the pylorus and the bile papilla is about four inches in length, and is called by 
the Mayo brothers the vestibule oj the duodenum. Here the acid gastric juice enters and may pro- 
duce an ulcer. The portion of the duodenum below the vestibule is not liable to ulcer, because 
it is protected by the alkaline bile and pancreatic juice. 
A duodenal ulcer may perforate a large duodenal vessel and cause death from hemorrhage, 
or may perforate the intestine and produce septic peritonitis. A perforated ulcer is treated 
by laparotomy and closure of the perforation. Occasionally ulceration of the duodenal glands 
(Curling's ulcer) may occur in cases of burns, but is not a very common complication. 
The vermiform appendix is very liable to become inflamed, the condition being known as 
appendicitis. This condition may be set up by a catarrhal inflammation arising in the appen- 
dix or derived from the colon. It may remain catarrhal and then subside. It may become 
purulent or may be purulent from the beginning. Anything which lessens vital resistance 
makes the appendix a ready prey to bacteria. Among causes which lessen resistance are fajcal 
concretions, twists of the mesoappendix cutting off the blood-supply, bruises inflicted by the Psoas 
muscle (Byron Robinson), blocking of the outlet of the appendix by catarrhal exudate, concre- 
tions, proliferated lymphoid tissue, or adhesions. Appendicitis may arise by the appendix becom- 
ing twisted, owing to the' shortness of its mesentery, in consequence of distention of the caecum. 
As the result of inflammation, its blood-supply, which is mainly through one large artery running 
in the mesoappendix, becomes interfered with. Again, in rarer cases, the inflammation is set 
up by the impaction of a solid mass of faeces or a foreign body in the appendix. The inflammation 
may result in ulceration and perforation, or in gangrene of the appendix the appendix may be 
blocked and full of pus, or abscess may form outside of it (appendicular abscess). These con- 
ditions require prompt operative interference, and in cases of recurrent attacks of appendicitis it 
is advisable to remove this diverticulum between the attacks. In external hernia the ileum 
is the portion of bowel most frequently herniated. When a part of the large intestine is 
involved, it is usually the caecum, and this may occur even on the left side. In some few cases 
the vermiform appendix has been the part implicated in cases of strangulated hernia, and has 
given rise to serious symptoms of obstruction. The diameter of the large intestine gradually 
diminishes from the caecum, which has the greatest diameter of any part of the bowel, to the 
point of junction of the sigmoid flexure with the rectum, at or a little below which point stricture 
most commonly occurs and diminishes in frequency as one proceeds upward to the caecum. 
When distended by some obstruction low down, the outline of the large intestine can be defined 
throughout nearly the whole of its course-all, in fact, except the hepatic and splenic flexures, 
which are more deeply placed; the distention is most obvious in the two flanks and on the front 
of the abdomen just above the umbilicus. The caecum, however, is that portion of the bowel 
which is, of all, most distended. It sometimes assumes enormous dimensions, and has been 
known to give way from the distention, causing fatal peritonitis. The hepatic flexure and the right 
extremity of the transverse colon are in close relationship with the liver, and abscess of this viscus 
sometimes bursts into the gut in this situation. The gall-bladder may become adherent to the 
colon, and gall-stones may find their way through into the gut, where they may become impacted 
or may be discharged per anum. The mobility of the sigmoid flexure renders it more liable to 
become the seat of a volvulus or twist than any other part of the intestine. It generally occurs 
in patients who have been the subjects of habitual constipation, and in whom, therefore, the 
mesosigmoid is elongated. The gut at this part being loaded with faeces, from its weight falls 
over the gut below, and so gives rise to the twist. 
The surgical anatomy of the rectum is of considerable importance. There may be congenital 
malformation due to arrest or imperfect development. Thus, there may be no invagination of 
the epiblast, and consequently a complete absence of the anus; or the hind-gut may be imper- 
fectly developed, and there may be an absence of the rectum, though the anus is developed; 
or the invagination of the epiblast may not communicate with the termination of the hind-gut 
from want of solution of continuity in the septum which in early foetal life exists between the 
two. The mucous membrane is thick and but loosely connected to the muscular coat beneath 
and thus favors prolapse, especially in children The vessels of the rectum are arranged as 
mentioned above, longitudinally, and are contained in the loose cellular tissue between the 
mucous and muscular coats, and receive no support from surrounding tissues, and this favors 
varicosity. Moreover, the veins, after running upward in a longitudinal direction for about five 
inches in the submucous tissue, pierce the muscular coats, and are liable to become constricted 
at this point by the contraction of the muscular wall of the gut. In addition to this there are no 
valves in the superior hemorrhoidal veins, and the vessels of the rectum are placed in a depen- 1326 
THE ORGANS OF DIGESTION 
dent position, and are liable to be pressed upon and obstructed by hardened feces. The anatom- 
ical arrangement, therefore, of the hemorrhoidal vessels explains the great tendency to the 
occurrence of piles. The presence of the Sphincter ani is of surgical importance, since it is the 
constant contraction of this muscle which prevents an ischio-rectal abscess from healing and 
tends to cause a fistula. Also, the reflex contraction of this muscle is the cause of the severe pain 
complained of in fissure of the anus. The relations of the peritoneum to the rectum are of 
importance in connection with the operation of removal of the lower end of the rectum for 
malignant disease. The membrane gradually leaves the rectum as it descends into the pelvis; 
first leaving its posterior surface, then the sides, and then the anterior surface to become 
reflected in the male on to the posterior wall of the bladder, forming the recto-vesical pouch, and 
in the female on to the posterior wall of the vagina, forming Douglas's pouch. The recto-vesical 
pouch of peritoneum extends to within three inches from the anus, so that it is not desirable 
to remove more than two and a half inches of the entire circumference of the bowel, for fear 
of the risk of opening the peritoneum. When, however, the disease is confined to the poste- 
rior surface of the rectum, or extends farther in this direction, a greater amount of the poste- 
rior wall of the gut may be removed, as the peritoneum does not extend on this surface to a 
lower level than five inches from the margin of the anus. The recto-vaginal or Douglas's pouch 
in the female extends somewhat lower than the recto-vesical pouch of the male, and therefore 
it is advisable to remove a less length of the tube in this sex. Of recent years, however, much 
more extensive operations have been done for the removal of cancer of the rectum, and in these 
the peritoneal cavity has necessarily been opened. If, in these cases, the opening is plugged 
with iodoform gauze until the operation is completed and then the edges of the wound in the 
peritoneum is accurately brought together with sutures, no evil result appears to follow. For 
cases of cancer of the rectum which are too low to be reached by abdominal section, and too 
high to be removed by the ordinary operation from below, Kraske has devised an operation 
which goes by his name. The patient is placed on his right side and an incision is made from 
the second sacral spine to the anus. The soft parts are now separated from the back of the 
left side of the sacrum as far as its left margin, and the greater and lesser sacro-sciatic liga- 
ments are divided. A portion of the lateral mass of the sacrum, commencing on the left border 
at the level of the third posterior sacral foramen, and running downward and inward through 
the fourth foramen to the cornu, is now cut away with a chisel. The left side of the wound 
being now forcibly drawn outward, the whole of the rectum is brought into view, and the dis- 
eased portion can be removed, leaving the anal portions of the gut, if healthy. The two divided 
ends of the gut can perhaps then be approximated and sutured together. Kraske's operation is 
in many cases preceded by the performance of iliac colostomy. In cancer high up in the 
rectum removal of the growth through the abdomen is sometimes practised, the divided lower 
end of the rectum being sutured to the divided upper end (Weir's operation). 
The colon frequently requires opening in cases of intestinal obstruction, and by some sur- 
geons this operation is performed in cases of cancer of the rectum, as soon as the disease is 
recognized, in the hope that the rate of growth may be retarded by removing the irritation pro- 
duced by the passage of fecal matter over the diseased surface. The operation of colostomy may 
be performed either in the inguinal or lumbar region; but inguinal colostomy (Maydl's opera- 
tion) has at the present day superseded the lumbar operation. The main reason for preferring 
this operation is that a spur-shaped process can be formed which prevents any fecal matter find- 
ing its way past the artificial anus and becoming lodged on the diseased structures below. The 
sigmoid flexure being surrounded by peritoneum, a coil can be drawn out of the wound, and 
when it is opened transversely a spur is formed, and this prevents any fecal matter finding its 
way from the gut above the opening into that below. The operation is performed by making an 
incision two or three inches in length from a point one inch internal to the anterior superior 
spinous process of the ilium, parallel to Poupart's ligament. The various layers of abdominal 
muscles are cut through, and the peritoneum opened and sewed to the external skin. The sigmoid 
flexure is now sought for, and pulled out of the wound and fixed by pushing a glass bar through 
a slit in the mesocolon. The two parts of the loop are sutured together. The intestine is now 
sutured to the parietal peritoneum. The wound is dressed, and either immediately or between 
the second to the fourth day, according to the requirements of the case, the protruded coil of 
intestine is opened. It is opened transversely with the Paquelin cautery. 
THE LIVER (HEPAR) (Figs. 936, 937, 938, 939). 
The liver is the largest gland in the body, and is situated in the upper and 
right part of the abdominal cavity, occupying almost the whole of the right hypo- 
chondrium, the greater part of the epigastrium, and extending into the left hypo- 
chondrium as far as the mammary line. In the male it weighs from fifty to sixty THE LIVER 
1327 
ounces; in the female, from forty to fifty. It is relatively much larger in the foetus 
than in the adult, constituting, in the former, about one-eighteenth, and in the 
latter, about one-thirty-sixth of the entire body-weight. Its greatest transverse 
measurement is from eight to nine inches. Vertically, near its lateral or right 
surface, it measures about six or seven inches, while its greatest antero-posterior 
diameter is on a level with the upper end of the right kidney and is from four to 
five inches. Opposite the vertebral column its measurement from before backward 
is reduced to about three inches. Its consistence is that of a soft solid; it is, 
however, friable and easily lacerated; its color is a dark reddish-brown, and its 
specific gravity is 1.05. 
To obtain a correct idea of its shape, it must be hardened in situ, and it will 
then be seen to present the appearance of a wedge, the base of which is directed 
to the right and the thin edge toward the left. Symington describes its shape as 
that "of a right-angled triangular prism with the right angles rounded off.'' It 
possesses five surfaces, viz., a superior, inferior, anterior, posterior, and a right lateral 
surface. 
Gall-bladder. 
Vena cava inferior. 
RIGHT LATERAL 
LIGAMENT. 
LEFT LATERAL' 
LIGAMENT. 
Fig. 936.-The liver. Upper surface. (Drawn from His's models.) 
The superior and anterior surfaces are separated from each other by a thick 
rounded border, and are attached to the Diaphragm and anterior abdominal wall 
by a triangular or falciform fold of peritoneum, the suspensory or falciform liga- 
ment, which divides the liver into two unequal parts, termed the right and left 
lobes (Figs. 936, 940, and 941). Except along the line of attachment of this liga- 
ment to the liver, the superior and anterior surfaces are covered by peritoneum. 
The Superior Area or Surface (facies superior) (Fig. 936).-The superior 
area or surface comprises a part of both lobes. Spalteholz considers as parts of 
the superior surface the right surface and the anterior surface. The superior sur- 
face is convex, and fits under the vault of the Diaphragm; its central part, however, 
presents a shallow depression, the cardiac depression (impress™ cardiaca}, which 
corresponds with the position of the heart on the upper surface of the Diaphragm. 
It is separated from the anterior, posterior, and lateral surfaces by thick, rounded 
borders. Its left extremity is continued into the under surface by a prominent 
sharp margin. 
The Anterior Area or Surface.-The anterior area or surface is large and 
triangular in shape, comprising also a part of both lobes. It is directed forward, 1328 
THE ORGANS OF DIGESTION 
and the greater part of it is in contact with the Diaphragm, which separates it 
from the right lower ribs and their cartilages. In the middle line it lies behind 
Receptaculum 
chyli. 
Great splanchnic 
nerve piercing 
crus. 
Great splanchnic 
nerve piercing 
crus. 
Semilunar 
ganglion. 
Semilunar 
ganglion. 
Fig. 937.-The relations of the viscera and large vessels of the abdomen. (Seen from behind, 
the last dorsal vertebra being well raised.) 
the ensiform cartilage, to the left of which it is protected by the seventh and 
eighth left costal cartilages. In the angle between the diverging rib cartilages 
of opposite sides the anterior surface is in contact with the abdominal wall. It THE LIVER 
1329 
is continuous with the inferior surface by a sharp margin, and with the superior 
and lateral surfaces by thick rounded borders. 
The Lateral or Right Area or Surface (Figs. 936 and 938).-The lateral or 
right area or surface is convex from before backward and slightly so from 
above downward. It is directed toward the right side, forming the base of the 
wedge, and lies against the lateral portion of the Diaphragm, which separates 
it from the lower part of the left pleura and lung, outside which are the right 
costal arches from the seventh to the eleventh inclusive. 
The Under or Visceral Area or Surface (facies inferior) (Figs. 938 and 939).- 
The under or visceral area or surface is uneven, concave, directed downward and 
backward and to the left, and is in relation with the stomach and duodenum, the 
hepatic flexure of the colon, and the right kidney. The surface is divided by a 
longitudinal fissure into a right and a left lobe, and is almost completely invested 
by peritoneum; the only parts where this covering is absent are where the gall- 
bladder is attached to the liver and at the transverse fissure, where the two layers 
of the lesser omentum are separated from each other by the blood-vessels and 
duct of the viscus. The under surface of the left lobe presents to the right and 
near the centre a rounded eminence, the omental tuberosity (tuber omentale) (Fig. 
938), which is in contact with the lesser omentum. It is surrounded by a broad 
depression, the gastric surface or impression (impressio gastrica), with which the 
stomach is in contact. Between the gall-bladder and the left lobe is the quad- 
rate lobe. The quadrate lobe is bounded to the left by the umbilical fissure or the 
fissure of the umbilical vein (fossa venae umbilicalis), which is the anterior portion 
of the longitudinal fissure and lodges the round ligament (ligamentum teres). The 
under surface of the right lobe is divided into two unequal portions by a fossa, 
which lodges the gall-bladder and is called the fossa vesicalis (fossa vesicae felleae)', 
the portion to the left, the smaller of the two, is somewhat oblong in shape, its 
antero-posterior diameter being greater than its transverse. It is known as the 
quadrate lobe (lobus quadratus), and is in relation with the pyloric end of the 
stomach (impressio pylorica) and the first portion of the duodenum. The portion 
of the under surface of the right lobe to the right of the fossa vesicalis presents 
two shallow concave impressions, one situated behind the other, the two being 
separated by a ridge. The anterior of these two impressions, the colic impression 
(impressio colica), is produced by the hepatic flexure of the colon; the posterior, 
the renal impression (impressio renalis), is occupied by the upper end of the 
right kidney (Fig. 938). To the inner side of the latter impression is a third 
and slightly marked impression, lying between it and the neck of the gall- 
bladder. This is caused by the second portion of the duodenum, and is known 
as the duodenal impression (impressio duodenalis). Just in front of the vena cava 
is a narrow strip of liver tissue, the caudate lobe, which connects the right infe- 
rior angle of the Spigelian lobe to the under surface of the right lobe. Imme- 
diately below it is the foramen of Winslow. 
The Posterior Area or Surface (facies posterior) (Figs. 937 and 939).-The 
posterior area or surface is rounded and broad behind the right lobe, but narrow 
on the left. Over a large part of its extent it is not covered by peritoneum; this 
uncovered area (Fig. 938) is about three inches broad, and is in direct contact with 
the Diaphragm, being united to it by areolar tissue. In this tissue are numerous 
small veins which join the portal circulation to the systemic circulation. The 
uncovered area is marked off from the upper surface by the line of reflection of 
the upper or anterior layer of the coronary ligament. It is in the same way 
marked off from the under surface of the liver by the line of reflection of the lower 
layer of the coronary ligament (Fig. 940). In its centre the posterior surface is deeply 
notched for the vertebral column and crura of the Diaphragm, and to the right 
of this it is indented for the inferior vena cava (fossa venae cavae), which is often THE ORGANS OF DIGESTION 
1330 
partly embedded in its substance. Close to the right of this indentation and 
immediately above the renal impression is a small triangular depressed area, the 
suprarenal impression (impressio suprarenalis) (Fig. 938), the greater part of which 
is devoid of peritoneum; it lodges the right suprarenal capsule, which is inserted 
between the liver and Diaphragm. To the left of the fossa for the inferior vena 
cava is the Spigelian lobe, which lies between the fissure for the vena cava and the 
fissure for the ductus venosus. Below and in front it projects and forms part of the 
posterior boundary of the transverse fissure. Here, to the right, it is connected 
with the under surface of the right lobe of the liver by the caudate lobe, and to 
the left it presents a tubercle, the tuberculum papillare (Fig. 938). It is opposite 
the tenth and eleventh dorsal vertebrae, and rests upon the aorta and crura of the 
Diaphragm, being covered by the peritoneum of the lesser sac. The lobe is 
nearly vertical in position, and is directed backward; it is longer from above 
downward than from side to side, and is somewhat concave in the transverse 
direction. On the posterior surface to the left of the Spigelian lobe is a groove, 
the oesophageal groove (impressio oesophagea), indicating the position of the 
abdominal portion of the oesophagus (Fig. 938). 
(Esophageal groove. 
Suprarenal 
impression 
(non-peritoneal). 
Fissure for ductus venosus. 
Suprarenal 
impression 
(peritoneal). 
Tuberculum 
candatum. 
Tuberculum 
papillare. 
Umbilical fissure. 
Transverse fissure. 
Fig. 938.-The liver. Posterior and inferior surfaces. (Drawn from His's models.) 
Prof. Cunningham divides the liver into two surfaces, a visceral and a parietal, 
and subdivides the parietal surface into a posterior area and superior area, an ante- 
rior area and a right area. The parietal surface is separated from the visceral 
surface by the inferior border or margin. 
The inferior border or margin (margo inferior is), posteriorly, is rather ill defined. 
It is the lower margin of the posterior surface; it follows the line of rib and is in 
contact with the right kidney. At the right side the lower margin is thick and 
distinct, and, as a rule, projects slightly below the thorax. The front of the 
inferior margin is called the anterior margin (margo anterior). It is a sharp edge 
which, on inspiration, corresponds to an oblique line on the abdominal wall 
drawn from "a point half an inch below the margin of the ribs (tip of tenth 
costal cartilage), on the right side, to a point an inch below the nipple on the 
left, and extending down in the middle line to a point half-way between the 
gladiolus and the umbilicus."1 
In men the anterior margin of the liver often corresponds to the lower margin 
of the ribs, but in women and children it is usually below the ribs in the line 
1 Ambrose Birmingham, in Cunningham's Text-book of Anatomy. THE LIVER 
1331 
indicated above. Opposite the attachment of the falciform ligament the anterior 
border often exhibits a deep notch, the umbilical notch (incisura umbilicalis), 
which is the anterior end of the fossa venae umbilicalis. Another notch, some- 
times present, corresponds to the fundus of the gall-bladder, and is known as the 
notch of the gall-bladder (incisura vesicae felleae). 
The left extremity of the inferior margin of the liver is thin and flattened from 
above downward. The margin passes posteriorly around the free end of the left 
lobe and terminates posteriorly at the oesophageal groove. 
Fissures.-Five fissures are seen upon the under and posterior surfaces of the 
liver, which serve to divide it into five lobes. They are: the umbilical fissure, 
the fissure of the ductus venosus, the transverse fissure, the fissure for the gall-bladder, 
and the fissure for the inferior vena cava. They are arranged in the form of the 
letter H. The left limb of the H is known as the longitudinal fissure. The 
right limb is formed in front by the fissure for the gall-bladder, and behind 
by the fissure for the inferior vena cava; these two fissures are separated from 
each other by the caudate lobe. The connecting bar of the II is the transverse or 
portal fissure. It separates the quadrate lobe in front from the caudate and 
Spigelian lobes behind. 
(Esophageal groove. 
Portal vein. 
Suprarenal i mp ress ion. 
Small 
omentum. 
RIGHT LATERAL 
LIGAMENT. 
LIGAMENTUM 
TERES. 
Hepatic artery. 
Common bile-duct. 
Fig. 939. -Posterior and under surfaces of the liver. (From Ellis.) 
The Longitudinal Fossa or Fissure (jossa longitudinalis sinistra).-The longi- 
tudinal fissure is a deep groove, which extends from the notch on the anterior 
margin of the liver to the upper border of the posterior surface of the organ. It 
separates the right and left lobes; the Transverse Fissure (Fig. 938) joins it, at 
right angles, and divides it into two parts. The anterior part is called the um- 
bilical fossa or fissure (jossa venae umbilicalis) (Fig. 938); it is deeper than the 
posterior, and lodges the umbilical vein in the foetus, and its remains (the round 
ligament) in the adult; the posterior part contains the ductus venosus, and is 
known as the fissure of the ductus venosus. This fissure lies between the quadrate 
lobe and the left lobe of the liver, and is often partially bridged over by a 
prolongation of the hepatic substance, the pons hepatis. 
The Fissure or Fossa of the Ductus Venosus (jossa ductus venosi) (Fig. 938) is 
the back part of the longitudinal fissure, and is situated mainly on the posterior 
surface of the liver. It lies between the left lobe and the lobe of Spigelius. It 1332 
THE ORGANS OF DIGESTION 
lodges in the foetus the ductus venosus, and in the adult a slender fibrous cord, 
the obliterated remains of that vessel. 
The Transverse or Portal Fissure {porta hepatis) (Fig. 938).-The transverse or 
portal fissure is a short but deep fissure, about two inches in length, extending 
transversely across the under surface of the left portion of the right lobe, nearer to 
its posterior surface than its anterior border. It joins, nearly at right angles, with 
the longitudinal fissure, and separates the quadrate lobe in front from the cau- 
date and Spigelian lobes behind. By the older anatomists this fissure was con- 
sidered the gateway {porta) of the liver; hence the large vein which enters at this 
fissure was called the portal vein (Fig. 939). Besides this vein, the fissure trans- 
mits the hepatic artery and nerves, and the hepatic duct and lymphatics. At 
their entrance into the fissure, the hepatic duct lies in front and to the right, 
the hepatic artery to the left, and the portal vein behind and between the duct 
and artery. 
The Fossa or Fissure for the Gall-bladder {fossa vesicae felleae).-The fossa or 
fissure for the gall-bladder is a shallow, oblong fossa, placed on the under surface 
of the right lobe, parallel with the longitudinal fissure. It extends from the 
anterior free margin of the liver, which is notched for its reception, to the right 
extremity of the transverse fissure. 
The Fissure or Fossa for the Inferior Vena Cava {fossa venae cavae) (Fig. 938).- 
fhe fissure or fossa for the inferior vena cava is a short, deep fissure, in some cases 
a complete canal, in consequence of the substance of the liver occasionally sur- 
rounding the vena cava. It extends obliquely upward from the lobus caudatus, 
which separates it from the transverse fissure, on the posterior surface of the liver, 
and separates the Spigelian from the right lobe. On slitting open the inferior 
vena cava the orifices of the hepatic veins will be seen opening into this vessel at 
its upper part, after perforating the floor of this fissure. 
Lobes.-The lobes of the liver, like the ligaments and fissures, are five in 
number-the right lobe, the left lobe, the lobus quadratus, the lobus Spigelii, and 
the lobus caudatus, the last three being merely parts of the right lobe. 
The Right Lobe {lobus hepatis dexter) (Figs. 936 and 938).-The right lobe is 
much larger than the left; the proportion between them being as six to one. It 
occupies the right hypochondrium, and is separated from the left lobe, on its upper 
and anterior surfaces by the falciform ligament; on its under and posterior surfaces 
by the longitudinal fissure; and in front by the umbilical notch. It is of a some- 
what quadrilateral form, its under and posterior surfaces being marked by three 
fissures-the transverse fissure, the fissure for the gall-bladder, and the fissure for 
the inferior vena cava, which separate its left part into three smaller lobes-the 
lobus Spigelii, lobus quadratus, and lobus caudatus. On it are seen four shallow 
impressions: one in front, for the hepatic flexure of the colon; a second behind, 
for the right kidney; a third internal, between the last-named and the gall-bladder, 
for the second part of the duodenum; and a fourth on its posterior surface, for the 
suprarenal capsule. 
The Lobus Quadratus or Square Lobe (Figs. 938 and 939) is situated on the 
under surface of the right lobe, is bounded in front by the inferior margin of the 
liver; behind, by the transverse fissure; on the right, by the fissure of the gall- 
bladder; on the left, by the umbilical fissure. 
The Lobus Spigelii {lobus caudatus [Spigeli]) (Figs. 938 and 939) is situated 
upon the posterior surface of the right lobe of the liver. It looks directly back- 
ward, and is nearly vertical in direction. It is bounded, above, by the upper layer 
of the coronary ligament; below, by the transverse fissure; on the right, by the 
fissure for the vena cava; and on the left, by the fissure for the ductus venosus. 
Its left upper angle forms part of the groove for the oesophagus. What is here 
called the lobus Spigelii, Spalteholz calls the lobus caudatus of Spigelius. THE LIVER 
1333 
The Lobus Caudatus or Tuberculum Caudatum (processus caudatus) (Fig. 938), or 
tailed lobe, is a small elevation of the hepatic substance extending obliquely out- 
ward, from the lower extremity of the Spigelian lobe to the under surface of the 
right lobe. It is situated behind the transverse fissure, and separates the fissure 
for the gall-bladder from the commencement of the fissure for the inferior vena 
cava. What is here called the lobus caudatus, Spalteholz calls the processus 
caudatus of the lobus caudatus of Spigelius. 
The Left Lobe (lobus hepatis sinister) (Figs. 936 and 938).-The left lobe is 
smaller and more flattened than the right. It is situated in the epigastric and 
left hypochondriac regions. Its upper surface is slightly convex; its under sur- 
face is concave, and presents a shallow depression for the stomach, the gastric 
impression. This is situated in front of the groove for the oesophagus, and is 
separated from the longitudinal fissure by the omental tuberosity, which lies against 
the small omentum and lesser curvature of the stomach. The posterior end of 
the left lobe frequently exhibits a flat projection, composed of connective tissue, 
and called the appendix fibrosa hepatis. In the adult, portions only of bile-ducts 
are present in it. In the newborn it is a definite portion of secreting liver substance, 
which later undergoes connective-tissue transformation. 
Ligaments.-The liver is connected to the under surface of the Diaphragm 
and the anterior walls of the abdomen and the inferior vena cava by six ligaments, 
four of which are peritoneal folds; the other two, which are the round ligament 
and the ligament of the ductus venosus, are fibrous cords, resulting from the 
obliteration of ftetal vessels. These ligaments are the falciform, two lateral, 
coronary, round, and the ligament of the ductus venosus. It is also attached to the 
lesser curvature of the stomach by the gastro-hepatic or small omentum. 
CORONARY^ 
LIGAMENT* 
SPIGELIAN 
LOBE 
pLEFT 
"lateral 
LIGAMENT 
RIGHT 
LATERAL 
LIGAMENT 
LEFT LOBE 
FALCIFORM 
LIGAMENT 
RIGHT 
LOBE 
Fig. 940.-The peritoneal ligaments of the liver. (Schematic.) (Poirier and Charpy.) 
The Falciform, Broad or Suspensory Ligament (ligamentum falciforme hepatis) 
(Figs. 936, 940, and 941).-The falciform or suspensory ligament is a broad and 
thin antero-posterior peritoneal fold, falciform in shape, its base being directed 
downward and backward, its apex upward and backward. It is attached by one 
margin to the under surface of the Diaphram, and the posterior surface of the 
sheath of the right Rectus muscle to within one inch of the umbilicus; by its 
hepatic margin it extends from the notch on the anterior margin of the liver, as 
far back as its posterior surface. 
The free edge or base of the falciform ligament reaches from a little above and to 
the right of the umbilicus to the umbilical fissure on the anterior margin of the liver. 
This free edge contains between its folds the round ligament of the liver. On the 
posterior surface of the liver the two peritoneal folds which constitute the falci- 
form ligament separate, the right fold passing into the upper fold of the coronary 
ligament, the left fold passing into the upper fold of the left lateral ligament. THE ORGANS OF DIGESTION 
1334 
The Lateral Ligaments (Figs. 936 and 940).-The lateral ligaments are two in 
number, and are called the right and left lateral ligaments. 
The Right Lateral Ligament (ligamentum triangulare dextrum) (Figs. 936 and 
940) is in reality the right extremity of the coronary ligament. This ligament is 
triangular in form, runs from the liver to the Diaphragm, and is formed by the 
apposition of the upper and lower layers of the coronary ligament. It is 
attached to the liver between its lateral and inferior surfaces. 
The Left Lateral Ligament (lig amentum triangulare sinistrum) (Figs. 936 and 
940) is also formed by apposition of the upper and lower layers of the coronary 
ligament. It is triangular in form, 
runs from the liver to the Dia- 
phragm, and is longer than the right 
lateral ligament. It is attached to 
the upper surface of the left lobe, 
where it lies, in front of the oesopha- 
geal opening in the Diaphragm. 
The Coronary Ligament (lig amentum 
coronarium hepatis) (Figs. 936 and 
940).-The coronary ligament con- 
nects the posterior surface of the liver 
to the Diaphragm. It is formed by 
the reflection of the peritoneum from 
the Diaphragm on to the upper and 
lower margins of the posterior sur- 
face of the liver. The coronary liga- 
ment consists of two layers, which 
are continuous on each side with the 
lateral ligaments, and, in front, with 
the falciform ligament. Between the layers a large triangular area is left un- 
covered by peritoneum, and is connected to the Diaphragm by firm areolar tissue. 
The Round Ligament (ligamentum teres hepatis) (Figs. 939 and 941).-The 
round ligament is a fibrous cord resulting from the obliteration of the foetal umbil- 
ical vein. It ascends from the umbilicus, in the free margin of the falciform 
ligament, to the notch in the anterior border of the liver, from which it may be 
traced along the umbilical fissure on the under surface of the liver, to the left 
branch of the portal vein. 
The Ligament of the Ductus Venosus (ligamentum venosum [Arantii]) is com- 
posed of slender bundles of fibrous tissue, and results from the obliteration of the 
ductus venosus of the foetus. It arises from the left branch of the portal vein, 
almost opposite the insertion of the round ligament, passes backward in the fissure 
of the ductus venosus, and, as it emerges from the liver, is attached to the vena cava. 
Support and Movability of the Liver.-The liver is movable within certain 
narrow limits. It moves with respiration. On inspiration it moves down with 
the Diaphragm to distinctly below the costal arch in the right nipple line. 
Much discussion has taken place as to what supports the liver in place. Syming- 
ton asserted that the ligaments do not give support, because they lie relaxed. 
Other observers (Graham, Steele) apparently demonstrate that the peritoneal 
ligaments do give some support to the liver. The connective tissue which unites 
the uncovered area of the right lobe of the liver to the Diaphragm and the hepatic 
veins which join the vena cava (Faure) do give distinct support. The chief factor 
in the support of the liver is the intra-abdominal pressure resulting from the 
tonic contraction of the abdominal muscles. When abdominal tension is normal 
the intestines are driven up and become a bed for the liver. Intrahepatic vascular 
tension aids in supporting the liver (Glenard). 
LIVER 
Fig. 941.-Diagram to show the relations oi the falci- 
form or suspensory and round ligaments to the liver and 
the abdominal wall. (Gerrish.) THE LIVER 
1335 
Abnormalities of the Liver.-The liver may be divided into many lobules, and 
such lobulation is most evident on the parietal surface of the right lobe. Lobula- 
tion is probably a pathological change. Occasionally the right lobe is small and 
the left large. 
The editor, in performing an abdominal operation, encountered a liver the 
left lobe of which was so large and the right so small as to suggest transposition 
or rotation of the organ. Such a change may result from abnormality of the 
foetal circulation or from syphilitic disease of the right lobe, producing cicatricial 
contraction.1 The left lobe may be very small; sometimes it is rudimentary. 
When the left lobe is very small an unusual amount of stomach is visible, and the 
entire gall-bladder can be seen from the front. In such a case the gall-bladder is 
usually displaced and it may actually "lie with its long axis in the transverse axis 
of the body."2 
DIAPHRAGMATIC 
GROOVE 
LOBE OF RIEDEL 
Fig. 942.-Deformed female liver. (Poirier and Charpy.) 
Atrophy of the left lobe is usually a congenital defect, but may result from 
syphilis. Small accessory lobes, about one inch in length, are not uncommon, and 
they are most often met with on the visceral surface of the right lobe. "When 
markedly pedunculated, they may form accessory livers. The Spigelian lobe is 
sometimes curiously pedunculated."3 
Accessory livers are fragments of hepatic tissue or rests, which are entirely 
separated from the liver. They are seldom met with. When they do exist their 
most common situation is in the suspensory ligament, but they have been found 
in the great omentum, in the peritoneum, wall of the gall-bladder, and in other 
situations. They may be congenital or may be due to atrophy of the pedicle of an 
accessory lobe or of a pedunculated lobe. Tight lacing alters the shape and posi- 
tion of the liver (Fig. 942). It may flatten the dome and increase the length of 
the anterior surface, this change being especially obvious in the right lobe, and a 
costal groove may be formed by the pressure of a rib. "When the elongated 
right lobe passes over the right kidney, there is atrophy of the hepatic substance 
1 H. D. Rolleston on Diseases of the Liver. * Ibid. 3 Ibid. THE ORGANS OF DIGESTION 
1336 
and thickening of the capsule, which is opaque and forms a hinge-like ligament 
between the main part of the right lobe above and the constricted lower portion. 
This lobe is variously termed partial hepatoptosis, constriction lobe, or the sus- 
tentacular formation of the right lobe (Hertz). The constriction furrow is pro- 
duced by the pressure of the corset in front and the resistance of the kidney 
behind. The constriction lobe tapers to a point, so that the shape of the liver, as 
seen from the front, is that of a right-angled triangle, with the apex downward."1 
The condition resembles Riedel's lobe. The left lobe may also project down, 
but not so markedly. Tight lacing may cause the entire organ to occupy a level 
higher than normal. Such a liver is thick and excessively convex above and 
thin below, and reaches to or laps over the spleen. In severe cases the superior 
surface is thrown into antero-posterior creases or folds. Linguiform or tongue-like 
lobe, Riedel's lobe or floating lobe (Fig. 942), may be congenital, may be due to tight 
lacing, or may arise in cholelithiasis or cholecystitis from the traction of adhesions. 
Such a lobe comes off from the right lobe. It may be a tapering mass of liver 
tissue, it may have a thin pedicle of liver tissue, or its pedicle may be merely a 
double fold of peritoneum. The gall-bladder may lie upon its under surface, or 
may be placed to the left of it. 
Vessels.-The blood-vessels connected with the liver are the hepatic artery, the 
portal vein and the hepatic veins. 
Fig. 943.-Schematic section of the liver. The fibron tunic shown in black and tne capsule of Glisson in red. 
The Hepatic Artery and Portal Vein (Figs. 418, 419, 489, and 944), accompanied 
by numerous lymphatics and nerves, ascend to the transverse fissure between the 
layers of the gastro-hepatic omentum, and in front of the foramen of Winslow, 
rhe hepatic duct, lying in company with them, descends from the transverse fissure 
between the layers of the same omentum. The relative position of the three 
structures in the lesser omentum (Fig. 859) is as follows: the hepatic duct lies to 
the right, the hepatic artery to the left, and the portal vein behind and between 
the other two. They enter the transverse fissure in the above-described order, but 
in that fissure undergo rearrangement, the duct being in front, the artery in the 
middle, and the vein behind. The artery, the vein, and the duct divide into a 
right and left branch and several smaller branches, and within the organ the 
vessels from the three sources accompany each other and divide at the same 
points; so each branch of the portal vein is accompanied by a branch of the 
hepatic artery and of the duct. They are enveloped in a loose areolar tissue, the 
capsule of Glisson (Fig. 943), which accompanies the vessels in their course through 
the portal canals in the interior of the organ. 
The Hepatic Veins (Fig. 421).-The hepatic veins convey the blood from the liver. 
They commence in the substance of the liver, in the capillary terminations of the por- 
tal vein and hepatic artery; these tributaries, gradually uniting, usually form three 
1 Rolleston, on Diseases of the Liver. THE LIVER 
1337 
veins, which converge toward the posterior surface of the liver and open into the 
portion of the inferior vena cava situated in the groove at the back part of 
this organ. Of these three veins, one from the right and another from the left 
lobe open obliquely into the vena cava; that from the middle of the organ and 
lobus Spigelii having a straight course. 
The hepatic veins have very little cellular investment; what there is binds their 
parietes closely to the walls of the canals through which they run; so that, on 
section of the organ, these veins remain widely open and solitary (Fig. 946), 
and may be easily distinguished from the branches of the portal vein (Fig. 947), 
which are more or less collapsed, and always accompanied by an artery and duct. 
The hepatic veins are destitute of valves. 
Structure.-The substance of the liver is composed of lobules held together by 
extremely fine areolar tissue, and of the ramifications of the portal vein, hepatic 
duct, hepatic artery, hepatic veins, lymphatics, and nerves, the whole being 
invested by a serous and a fibrous coat. 
GALL 
BLADDER 
COMMON DUCT- 
FORAMEN OF. 
WINSLOW 
HEPATIC 
ARTERY 
DUODENUM. 
Fig. 944.-The relations of the vessels as they pass into the transverse fissure of the liver. (Poirier and Charpy.) 
The Serous Coat (tunica serosa).-The serous coat is derived from the perito- 
neum, and invests the greater part of the surface of the organ. It is intimately 
adherent to the fibrous coat. 
The Areolar or Fibrous Coat (capsula fibrosa [Glissoni]).--The areolar or fibrous 
coat lies beneath the serous investment and covers the entire surface of the organ. 
It is difficult of demonstration, excepting where the serous coat is deficient. At 
the transverse fissure it is thick and evident, is known as the capsule of Glisson, 
and envelops the vessels which enter the liver and passes with them along the 
portal canals. The areolar tissue which surrounds and binds together the liver 
lobules is continuous with the areolar coat. 
The Lobules (lobuli hepatis) (Fig. 949).-The lobules form the chief mass of 
the hepatic substance; they may be seen either on the surface of the organ or by 
making a section through the gland. They are small granular bodies about the size 
of a millet-seed, measuring from one-twentieth to one-tenth of an inch in diameter. 
In the human subject their outline is very irregular, but in some of the lower 1338 
THE ORGANS OF DIGESTION 
animals (for example, the pig) they are well defined, and when divided transversely 
have a polygonal outline. If divided longitudinally they are more or less foliated 
or oblong. The bases of the lobules are clustered around the smallest radicles 
of the hepatic veins (sublob ular veins'), to which each is connected by means of a 
small branch which issues from the centre of the lobule (intralobular vein). The 
remaining part of the surface of each lobule is imperfectly isolated from the sur- 
rounding lobules by a thin stratum of areolar tissue in which are ducts and a plexus 
of vessels, the interlobular plexus (Figs. 948 and 949). In some animals, as the 
pig, the lobules are completely isolated one from another by this interlobular areolar 
tissue. 
If one of the sublobular veins be laid open, the bases of the lobules may be 
seen through the thin wall of the vein on which they rest, arranged in the form 
of a tessellated pavement, the centre of each polygonal space presenting a minute 
aperture, the mouth of an intralobular vein (Fig. 946). 
Microscopic Appearance.-Each lobule is composed of a mass of cells, hepatic 
cells (Fig. 945), surrounded by a dense capillary plexus, composed of vessels which 
ABC a 
Fig. 945.-The hepatic cells at different stages of digestion. (Heidenhain.) 
penetrate from the circumference to the centre of the lobule, and terminate in a 
single straight central vein, which runs through its centre, to open at its base into 
one of the radicles of the hepatic vein. Between the cells are also the minute com- 
mencements of the bile-ducts. Therefore in the lobule we have all the essentials of 
a secreting gland; that is to say: (1) cells, by which the secretion is formed; (2) 
blood-vessels, in close relation with the cells, containing the blood from which 
the secretion is derived; and (3) ducts, by which the secretion, when formed, is 
carried away. Each of these structures will have to be further considered. 
(1) The Hepatic Cells are epithelial in nature and of more or less spheroidal form, 
but may be rounded, flattened, or many-sided from mutual compression. They 
vary in size from the to the an in diameter. They consist of a 
honeycomb network (Klein) without any cell-wall, and contain one or sometimes 
two distinct nuclei. In the nucleus is a highly refracting nucleolus with granules. 
Embedded in the honeycomb network are numerous yellow particles, the coloring 
matter of the bile, and oil-globules. The cells adhere together by their surfaces so 
as to form rows, which radiate from the centre to the circumference of the lobules.1 
As stated above, they are the chief agents in the secretion of the bile. 
(2) The Blood-vessels.-The blood in the capillary plexus around the liver-cells 
is brought to the liver principally by the portal vein, but also to a certain extent 
by the hepatic artery. For the sake of clearness the distribution of the blood 
derived from the hepatic artery may be considered first. 
The Hepatic Artery, entering the liver at the transverse fissure with the portal 
vein and hepatic duct, ramifies with these vessels through the portal canals. It 
gives off vaginal branches which ramify in the capsule of Glisson, and appear to 
be destined chiefly for the nutrition of the coats of the large vessels, the ducts, 
' Del^pine states that there are evidences of the arrangement of these cells in the form of columns, which 
form tubes with narrow lumina branching from terminal bile-ducts. This branching is evidenced by a diverg- 
ence of the columns from lines extending between adjacent portal vessels. The columns of cells group around 
terminal bile-ducts, and not around the so-called intralobular veins. (Lancet, 1895, vol. i. p. 1254.)-Ed. of 15th 
English edition. THE LIVER 
1339 
and the investing membranes of the liver. It also gives off capsular branches 
which reach the surface of the organ, terminating in the fibrous coat in stellate 
plexuses. Finally it gives off interlobular branches (rami arteriosi interlobulares) 
which form a plexus on the outer side of each lobule, to supply its wall and the 
accompanying bile-ducts. From this plexus lobular branches enter the lobule 
Hepatic 
artery. 
Portal vein. 
^Portion of 
canal from 
which vein 
has been 
removed. 
Orifices of intralobular veins. 
Fig. 946.-Longitudinal section of an hepatic 
vein. (After Kiernan.) 
Fig. 947.- Longitudinal section of a small portal 
vein and canal. (After Kiernan.) 
and end in the capillary network between the cells. Some anatomists, however, 
doubt whether it transmits any blood directly to the capillary network. 
The Portal Vein also enters at the transverse fissure and runs through the 
portal canals, enclosed in Glisson's capsule, dividing into branches in its course, 
Interlobular 
vein. 
Trunk of intralobular 
vein. 
Intralobular rein. 
Fig. 948.-Horizontal section of liver (dog.) 
which finally break up into a plexus, the interlobular plexus, in the interlobular 
spaces. In their course these branches receive the vaginal and capsular veins, 
corresponding to the vaginal and capsular branches of the hepatic artery (Fig. 
947). Thus it will be seen that all the blood carried to the liver by the portal vein 
and hepatic artery, except perhaps that derived from the interlobular branches of THE ORGANS OE DIGESTION 
1340 
the hepatic artery, directly or indirectly finds its way into the interlobular plexus. 
From this plexus the blood is carried into the lobule by fine branches which pierce 
its wall and then converge from the circumference to the centre of the lobule, form- 
Fig. 949.-Horizontal section of a liver lobule. 1, central vein; 2, converging vessels ; 3, interlobular plexus. 
(Poirier and Charpy.) 
ing a number of converging vessels which are connected by transverse branches 
(Figs. 948 and 949). In the interstices of the network of vessels thus formed are 
situated, as before said, the liver-cells: and here it is that the blood is brought into 
Fig. 950.-X-ray picture of the bile-ducts and the pancreatic ducts. (Byron Robinson.) 
intimate connection with the liver-cells and the bile is secreted. Arrived at the 
centre of a lobule, all these minute vessels empty themselves into one vein, of 
considerable size, which runs down the centre of the lobule from apex to base 
and is called the intralobular or central vein (vena interlobularis) (Fig. 949). At the THE LIVER 
1341 
base of the lobule this vein opens directly into the sublobular vein, with which the 
lobule is connected, and which, as before mentioned, is a radicle of the hepatic vein. 
The sublobular veins, uniting into larger and larger trunks, end at last in the hepatic 
veins, which do not receive any intralobular veins. Finally, the hepatic veins, as 
mentioned on page 767, converge to form three large trunks which open into the 
inferior vena cava, while that vessel is situated in the fissure appropriated to it 
at the back of the liver. 
(3) The Ducts.-Having shown how the blood is brought into intimate relation 
with the hepatic cells in order that the bile may be secreted, it remains now only 
to consider the way in which the secretion, having been formed, is carried away. 
Several views have prevailed as to the mode of origin of the hepatic ducts; it 
seems, however, to be clear that they commence by little passages which are 
formed between the cells, and which have been termed intercellular biliary pass- 
ages, bile-capillaries or bile-canaliculi (ductus biliferi). These passages are merely 
little channels or spaces left between the contiguous surfaces of two cells or in the 
Biliary 
duct. 
Hepatic 
cells. 
Capillary. 
Biliary duct. 
Fig. 952.-A transverse section of a small portal canal 
and its vessels. 1, portal vein ; 2, interlobular branches; 
3, vaginal branches ; 4, hepatic duct ; 5, hepatic artery. 
(After Kiernan.) 
angle where three or more liver-cells meet (Fig. 951), and it seems doubtful 
whether there is any delicate membrane forming the wall of the channel. 
Heidenhain, however, thinks they have coats. The channels thus formed radi- 
ate to the circumference of the lobule, and, piercing its wall, form a plexus 
{interlobular) between the lobules. From this plexus interlobular ducts {ductus 
interlobulares) are derived which pass into the portal canals, become enclosed in 
Glisson's capsule, and, accompanying the portal vein and hepatic artery (Fig. 
952), join with other ducts to form two main trunks, the right and left branches of 
the hepatic duct, which leave the liver at the transverse fissure, and by their union 
form the hepatic duct. 
Structure.-The coats of the smallest biliary ducts, which lie in the inter- 
lobular spaces, are a connective-tissue coat, in which are muscle-cells, arranged 
both circularly and longitudinally, and an epithelial layer, consisting of short 
columnar cells. In the larger ducts, which lie in the portal canals, there are a 
number of orifices disposed in two longitudinal rows, which were formerly regarded 
as the openings of mucous glands, but which are merely the orifices of tubular 
recesses. They occasionally anastomose, and from the sides of them saccular 
dilatations are given off. 
Lymphatics of the Liver (Fig. 506).-The lymphatics in the substance of the liver 
commence in lymphatic spaces around the capillaries of the lobules; they accompany 
Fig. 951.-Section of liver. THE Oil GANS OF DIGESTION 
1342 
the vessels of the interlobular plexus, often enclosing and surrounding them. 
These unite and form larger vessels, which run in the portal canals, enclosed in 
Glisson's capsule, and emerge at the portal fissure to be distributed in the manner 
described. Other superficial lymphatics arise from the superficial lobules, pass 
under the peritoneum, and form a close plexus, where this membrane covers 
the liver. The first-named group of lymphatics give origin to the deep collecting 
trunks, the second to the superficial collecting trunks. According to Poirier, 
Cuneo and Delamare,1 one group of deep collecting trunks accompanies the portal 
vein, there being fifteen to eighteen of them emerging from the transverse fissure. 
They empty into the glands of the hilum. Another group accompanies the hepatic 
veins. There are five or six trunks which pass through the Diaphragm and ter- 
minate in the glands about the vena cava (intrathoracic glands). According to the 
above-cited authorities, the superficial trunks of the superior surface are divided 
into posterior, anterior, and superior trunks. Some of the posterior trunks ter- 
minate in the glands about the coeliac axis, others in the glands about the lower 
portion of the vena cava in the thorax; others in the glands about the abdominal 
portion of the oesophagus. The anterior trunks which are limited to the right 
lobe pass to the glands of the hilum. The superior trunks ascend in the suspen- 
sory ligament. Some pass to the glands about the vena cava, just above the 
Diaphragm; others to the hepatic glands. The balance unite to form a very large 
trunk, which passes through the Diaphragm and divides into branches which enter 
the glands back of the base of the ensiform cartilage. 
Nerves of the Liver.-The nerves of the liver are derived from the left pneumo- 
gastric and the solar plexus of the sympathetic. The branches of the pneumo- 
gastric ascend from in front of the stomach within the lesser omentum. The 
sympathetic nerves pass along the hepatic artery from the coeliac plexus. Idle 
nerves enter the liver at the transverse fissure and accompany the vessels and 
ducts to the interlobular spaces. Here, according to Korolkow, the medullated 
fibres are distributed almost exclusively to the coats of the blood-vessels; while 
the non-medullated fibres enter the lobules and ramifv between the cells. 
The Excretory Apparatus of the Liver. 
The excretory apparatus of the liver consists of (1) the hepatic duct, which, 
as we have seen, is formed by the junction of the two main ducts, which pass 
out of the liver at the transverse fissure, and are formed by the union of the bile- 
capillaries; (2) the gall-bladder, which serves as a reservoir for the bile; (3) the 
cystic duct, which is the duct of the gall-bladder; and (4) the common bile-duct, 
formed by the junction of the hepatic and cystic ducts. 
The Hepatic Duct (ductus hepaticus) (Figs. 953, 954, and 956).-Two main 
trunks of nearly equal size issue from the liver at the transverse fissure, one from 
the right, the other from the left lobe; these unite to form the hepatic duct, which 
then passes downward and to the right for about an inch and a half or two 
inches, between the layers of the lesser omentum, where it is joined at an acute 
angle by the cystic duct, and so forms the ductus communis choledochus. The 
hepatic duct, as it descends from the transverse fissure of the liver, between the 
two layers of the lesser omentum, lies in company with the hepatic artery and 
portal vein (Fig. 944). 
The Gall-bladder (vesica fellea) (Figs. 859, 861, 938, 944, and 953).-The 
gall-bladder is the reservoir for the bile; it is a conical or pear-shaped musculo- 
membranous sac, lodged in a fossa on the under surface of the right lobe of the 
liver, and fixed in it by connective tissue, and extending from near the right 
extremity of the transverse fissure to the anterior border of the organ. It is 
1 The Lymphatics. Translated and edited by Cecil H. Leaf. THE EXCRETORY APPARATUS OF THE LIVER 
1343 
about four inches in length, one inch in breadth at its widest part, and holds from 
eight to ten drachms. It is divided into a fundus, body, and neck. The fundus 
(fundus vesicae felleae), or broad extremity, is 
directed downward, forward, and to the right, 
and projects beyond the anterior border of the 
liver; the body (corpus vesicae felleae) and neck 
(collum vesicae felleae) are directed upward and 
backward to the left. The neck of the gall- 
bladder is on a slightly higher level than the 
lowest point of the gall-bladder; thus the weight 
of the bile is away from rather than toward 
the outlet. The upper surface of the gall- 
bladder is attached to the liver by connective 
tissue and vessels. The under surface is 
covered by peritoneum, which is reflected on to 
it from the surface of the liver. Occasionally 
the whole of the organ is invested by the ser- 
ous membrane, and is then connected to the 
liver by a kind of mesentery. 
Relations.-The body of the gall-bladder is 
in relation, by its upper surface, with the 
liver, to which it is connected by areolar tissue 
and vessels ; by its under surface, with the 
commencement of the transverse colon ; and 
farther back, with the upper end of the de- 
scending portion of the duodenum or some- 
times with the pyloric end of the stomach or 
the first portion of the duodenum. The fundus 
is completely invested by peritoneum ; it is in 
relation, in front, with the abdominal parietes, 
immediately below the ninth costal cartilage; 
behind, with the transverse arch of the colon. 
The neck is narrow, and curves upon itself like the letter S; at its point of 
connection with the cystic duct it presents a well-marked constriction. 
COM MON. 
duct' 
SPIRAL 
VALVES 
HEPATIC 
DUCT 
CYSTIC 
DUCT 
GALL* 
BLADDER 
Fig. 953.-The gall-bladder and bile-ducts, 
cut through. (Spalteholz.) 
When the gall-bladder is distended with bile or filled with calculi, the fundus may be felt 
through the abdominal parietes, especially in an emaciated subject; the relations of this sac will 
also serve to explain the occasional occurrence of abdominal biliary fistulae, through which biliary 
calculi may pass out, and of the passage of calculi from the gall-bladder into the stomach, duod- 
enum, or colon, which occasionally happens. 
Structure.-The gall-bladder consists of three coats-serous, fibrous and mus- 
cular, and mucous. 
The External or Serous Coat (tunica serosa vesicae jelleae) is derived from the peri- 
toneum; it completely invests the fundus, but covers the body and neck only on 
their under surfaces. 
The Fibro-muscular Coat (tunica muscularis vesicae felleae) is a thin but strong 
layer which forms the framework of the sac, consisting of dense fibrous tissue which 
interlaces in all directions and is mixed with plain muscular fibres which are dis- 
posed chiefly in a longitudinal direction, a few running transversely. 
The Internal or Mucous Coat (tunica mucosa vesicae felleae) is loosely connected 
with the fibrous layer. It is generally tinged with a yellowish-brown color, and 
is everywhere elevated into minute rugae, by the union of which numerous meshes 
are formed, the depressed intervening spaces having a polygonal outline. The 
meshes are smaller at the fundus and neck, being most developed about the centre THE ORGANS OF DIGESTION 
1344 
of the sac. Opposite the neck of the gall-bladder the mucous membrane projects 
inward in the form of oblique ridges or folds, forming a sort of screw-like or spiral 
valve (Fig. 953). 
The mucous membrane is covered with columnar epithelium, and secretes an 
abundance of thick viscid mucus; it is continuous through the hepatic duct with 
the mucous membrane lining the ducts of the liver, and through the ductus com- 
munis choledochus with the mucous membrane of the duodenum. 
The Cystic Duct (ductus cysticus}.-The cystic duct, the smallest of the three 
biliary ducts, is about an inch and a half in length. It passes obliquely downward 
and to the left from the neck of the gall-bladder, and joins the hepatic duct to form 
the common bile-duct. It lies in the gastro-hepatic omentum in front of the portal 
GALL-BLADDER 
DUCT OF 
WIRSUNG 
SPHINCTER OF 
DUCT OF WIRSUNG 
COMMON 
DUCT 
HEPATIC 
DUCT 
CYSTIC 
DUCT 
SPHINCTER OF 
COMMON DUCT 
Fig. 955.-The sphincter of the common bile-duct. 
(Poirier and Charpy.) 
vein, the hepatic artery lying to its left 
side. The mucous membrane lining its in- 
terior is thrown into a series of crescentic 
folds, from five to twelve in number, similar 
to those found in the neck of the gall-blad- 
der. They project into the duct in regular 
succession, and are directed obliquely round 
the tube, presenting much the appearance 
of a continuous spiral valve (valvula spiralis 
[Heisteri]) (Fig. 953). When the duct is 
distended, the spaces between the folds 
are dilated, so as to give to its exterior 
a sacculated appearance. 
The Ductus Communis Choledochus or 
Common Bile-duct (ductus choledochus') 
Figs. 953 and 954), the largest of the three, 
is the common excretory duct of the liver and gall-bladder. It is about three 
inches in length, is of the diameter of a goose-quill, and is formed by the junction 
of the cystic and hepatic ducts. 
It descends within the two layers and along the right border of the lesser omen- 
tum behind the first portion the duodenum, in front of the portal vein, and to the 
right of the hepatic artery (Fig. 859); then passes either between the pancreas 
and descending portion of the duodenum, or through the head of the pancreas. 
In fifty-eight dissections Prof. Biingner found that it passed through the pan- 
creas fifty-five times and over the head only three times. Even when it passes 
through the pancreas it almost always joins the pancreatic duct outside of the 
gland. It descends by the right side of the pancreatic duct and passes with it 
obliquely through the wall of the descending portion of the duodenum between 
the mucous and muscular coats in the submucous tissue for one-half to three- 
COMMON 
DUCT 
PANCREATIC 
DUCT 
AMPULLA 
OF VATER 
WALL OF 
DUODENUM 
Fig. 954.-The biliary ducts. Schematic. 
(Poirier and Charpy.) THE EXCRETORY APPARATUS OE THE LIVER 
1345 
quarters of an inch. The two ducts usually unite just before opening into the 
duodenum (Figs. 954, 955, and 957), but may remain independent throughout. 
The ampulla of Vater (Fig. 954) is the cavity formed by the fusion of the two 
ducts, and is much larger than the opening on the bile-papilla. The two ducts 
open by a common orifice, or by two separate orifices, upon the summit of a papilla, 
situated at the inner side of the descending portion of the duodenum, a little 
below its middle and about three or four inches below the pylorus. The muscle 
of the common duct has a certain amount of sphincter power (Fig. 955), which 
serves to prevent the entrance of duodenal contents through the small aperture, 
but is not sufficiently powerful to prevent the flow of bile and pancreatic juice. 
Structure.-The coats of the large biliary ducts are an external or fibrous and 
an internal or mucous. The fibrous coat is composed of strong fibio-areolar tissues, 
CIRCULAR 
MUSCULAR 
Fl BRES 
LONGITUDINAL 
MUSCULAR FIBRES 
MUCOUS. 
COAT 
ACCESSORY 
PANCREATIC 
DUCTS 
BILE-DUCT 
PANCREATIC 
DUCT 
Fig. 957.-Diagram showing the bile and 
pancreatic ducts piercing the wall of the 
duodenum obliquely. (Cunningham.) 
with a certain amount of mus- 
cular tissue arranged, for the 
most part, in a circular manner 
around the duct. The mucous 
coat is continuous with the lin- 
ing membrane of the hepatic 
ducts and gall-bladder, and 
also with that of the duodenum; 
and,like the mucous membrane 
of these structures, its epithe- 
lium is of the columnar variety. 
It is provided with numerous 
mucous glands, which are lobu- 
lated and open by minute orifices scattered irregularly in the larger ducts. It is 
questionable if the smallest biliary ducts, which lie in the interlobular spaces, have 
any coats. Heidenhain thinks they have a connective-tissue coat, in which are 
muscle-cells arranged both circularly and longitudinally, and an epithelial layer, 
consisting of short columnar cells. 
Dimensions of the Bile-ducts.-The hepatic duct is about two inches in length, 
and its lumen is one-sixth of an inch in diameter. The cystic duct is about one 
and one-half inches in length, and its lumen one-twelfth of an inch in diameter. 
The common duct is about three inches in length, and its lumen is one-quarter of 
an inch in diameter. The duodenal opening is smaller than the common duct. 
The ducts are capable of considerable distention, but the duodenal opening can- 
not be dilated (Hyrtll. 
Fig. 956.-Part of the bile-duct and the pancreatic ducts. C 
and B, calculi; Sa, Santorini's duct; P, pancreatic duct; III and 
IV, ducts from the right and left lobes of the liver; II, cystic duct; 
C, gall-bladder; A, common duct. (Byron Robinson.) 1346 
THE ORGANS OF DIGESTION 
Blood-vessels, Lymphatics and Nerves of the Gall-bladder and Bile-ducts.-The cystic 
artery (Fig. 418), a branch from the right division of the hepatic, supplies the gall- 
bladder and cystic duct with blood. It passes along the cystic duct, and on reach- 
ing the gall-bladder divides into an upper branch and a lower branch. The upper 
branch lies between the gall-bladder and the liver and sends branches to each. 
The lower branch is between the peritoneum and the wall of the gall-bladder. 
The cystic veins empty into the portal vein. The common duct receives branches 
from the superior pancreatico-duodenal artery. There is a submucous lymphatic net- 
work and a muscular lymphatic network. The lymphatics are much less numer- 
ous at the fundus of the gall-bladder than at the neck or in the extra-hepatic ducts. 
The collecting trunks (Fig. 506) end in glands along the cystic and common ducts, 
and these glands are in communication with the duodenal lymphatics and the 
lymphatics from the head of the pancreas. The nerves of the gall-bladder and 
bile-ducts come from the coeliac plexus of the sympathetic. The adjacent peri- 
toneum is plentifully supplied with nerves (Byron Robinson). 
The Bile (fel).-The bile is a reddish-brown or greenish fluid. It contains pig- 
ments (bilirubin and biliverdin), fats and soaps, cholesterin, sodium salts of glyco- 
cholic and taurocholic acid, lecithin, and nucleo-albumin furnished by the mucous 
membrane. There are also present CO2; chlorides, carbonates, phosphates, and 
sulphates of the alkalies and of calcium, and iron. The amount normally 
secreted is from one pint to one and one-half pints in the twenty-four hours. 
Surface Relations.-The liver is situated in the right hypochondriac and the epigastric 
regions, and is moulded to the arch of the Diaphragm. In the greater part of its extent it lies 
under cover of the lower ribs and their cartilages, but in the epigastric region it comes in con- 
tact with the abdominal wall, in the subcostal angle. The upper limit of the right lobe of the 
liver may be defined in the middle line by the junction of the mesosternum with the ensiform 
cartilage; on the right side the line must be carried upward as far as the fifth rib cartilage 
in the line of the nipple and then downward to reach the seventh rib at the side of the chest. 
The upper limit of the left lobe may be defined by continuing this line to the left with an inclina- 
tion downward to a point about two inches to the left of the sternum on a level with the sixth 
left costal cartilage. The lower limit of the liver may be indicated by a line drawn half an inch 
below the lower border of the thorax on the right side as far as the ninth right costal cartilage, 
and thence obliquely upward across the subcostal angle to the eighth left costal cartilage. A 
slight curved line with its convexity to the left from this point-i. e., the eighth left costal 
cartilage-to the termination of the line indicating the upper limit will denote the left margin of 
the liver. The fundus of the gall-bladder approaches the surface behind the anterior extremity 
of the ninth costal cartilage, close to the outer margin of the Right rectus muscle. 
It must be remembered that the liver is subject to considerable alterations in position, and 
the student should make himself acquainted with the different circumstances under which this 
occurs, as they are of importance in determining the existence of enlargement or other diseases 
of the organ. 
Its position varies according to the posture of the body. In the erect position in the adult 
male the edge of the liver projects about half an inch below the lower edge of the right costal 
cartilages, and its anterior border can be often felt in this situation if the abdominal wall is thin. 
In the supine position the liver gravitates backward and recedes above the lower margin of the 
ribs, and cannot then be detected by the finger. In the prone position it falls forward, and can 
then generally be felt in a patient with loose and lax abdominal walls. Its position varies also 
with the ascent or descent of the Diaphragm. In a deep inspiration the liver descends below 
the ribs; in expiration it is raised behind them. Again, in emphysema, where the lungs are 
distended and the Diaphragm descends very low, the liver is pushed down; in some other dis- 
eases, as phthisis, where the Diaphragm is much arched, the liver rises very high up. Pressure 
from without, as in tight lacing, by compressing the lower part of the chest, displaces the liver 
considerably, its anterior edge often extending as low as the crest of the ilium; and its convex 
surface is often at the same time deeply indented from the pressure of the ribs. Again, its posi- 
tion varies greatly according to the greater or less distention of the stomach and intestines. 
When the intestines are empty the liver descends in the abdomen, but when they are distended 
it is pushed upward. Its relations to surrounding organs may also be changed by the growth of 
tumors or by collections of fluid in the thoracic or abdominal cavities. 
Surgical Anatomy.-Movable liver or hepatoptosis is a rare condition, in which the liver 
moves or can be moved from its normal position. It is due to lessened tone of the abdominal THE EXCRETORY APPARATUS OE THE LIVER 
1347 
muscles and relaxation of the liver supports. In movable liver the organ may be rotated on its 
vertical axis or on its transverse axis. Tongue-like lobes have been referred to. On account of 
its large size, its fixed position, and its friability, the liver is more frequently ruptured than 
any of the abdominal viscera. The rupture may vary considerably in extent, from a slight 
scratch to an extensive laceration completely through its substance, dividing it into two parts. 
Sometimes an internal rupture without laceration of the peritoneal covering takes place, and 
such injuries are most susceptible of repair; but small tears of the surface may also heal; when, 
however, the laceration is extensive, death usually takes place from hemorrhage, on account 
of the fact that the hepatic veins are contained in rigid canals in the liver-substance and are 
unable to contract, and are moreover unprovided with valves. The liver may also be torn 
by the end of a broken rib perforating the Diaphragm. The liver may be injured by stabs 
or other punctured wounds, and when these are inflicted through the chest-wall both pleural 
and peritoneal cavities may be opened up and both lung and liver be wounded. In cases of 
wound of the liver from the front, protrusion of a part of this viscus may take place, but can gen- 
erally easily be replaced. In cases of laceration of the liver, when there is evidence that bleeding 
is going on, the abdomen must be opened, the laceration sought for, and the bleeding arrested. 
This may be done temporarily by introducing the forefinger into the foramen of Winslow and 
placing the thumb on the gastro-hepatic omentum and compressing the hepatic artery and portal 
vein between the two. Any bleeding points can then be seen. Bleeding is, if possible, arrested 
by suture ligatures. The edges of a small laceration are simply brought together and sutured by 
means of a blunt, curved, round needle passed from one side of the wound to the other. All sutures 
must be passed before any are tied, and this must be done with the greatest gentleness, as the liver 
substance is very friable. If suture fails the actual cautery may succeed. When the laceration is ex- 
tensive, the liver is sutured to the abdominal wall to hold it firm when pressure is applied, and then 
the laceration is packed with a piece of iodoform gauze, the end of which is allowed to hang out 
of the external wound. Abscess of the liver is of not infrequent occurrence, and may open in many 
different ways on account of the relations of this viscus to other organs. Thus it may burst into 
the lung, the pus being coughed up, or into the stomach; the pus perhaps being vomited, it may 
burst into the colon or into the duodenum, or, by perforating the Diaphragm, it may empty 
itself into the pleural cavity. Frequently it makes its way forward, and points on the anterior 
abdominal wall, and finally it may burst into the peritoneal or pericardiac cavity. Abscesses 
of the liver require opening, and this must be done by an incision in the abdominal wall, in the 
thoracic wall, or in the lumbar region, according to the direction in which the abscess is tracking. 
The incision through the abdominal wall is to be preferred when possible. The abdominal wall 
is incised over the swelling, and unless the peritoneum is adherent, gauze is packed all around 
the exposed liver surface and the abscess opened, if deeply seated, preferably by the thermo- 
cautery. Hydatid cysts are more often found in the liver than in any other of the viscera. The 
reason of this is not far to seek. The embryo of the egg of the taenia echinococcus being liberated 
in the stomach by the disintegration of its shell, bores its way through the gastric walls and 
usually enters a blood-vessel, and is carried by the blood-stream to the hepatic capillaries, where 
its onward course is arrested, and where it undergoes development into the fully formed hydatid. 
Tumors of the liver have recently been subjected to surgical treatment by removal of a portion 
of the organ. The abdomen is opened and the diseased portion of liver exposed; the circulation 
is controlled by compressing the portal vein and the hepatic artery in the gastro-hepatic omen- 
tum and a wedge-shaped portion of liver containing the tumor removed; the divided vessels 
are ligated and the cut surfaces brought together and sutured in the manner directed above. 
When the gall-bladder or one of its main ducts is ruptured, which may occur independently 
of laceration of the liver, death usually occurs from peritonitis. If the symptoms have led to 
the performance of a laparotomy and a small rent is found, it should be sutured; if an exten- 
sive opening is found the gall-bladder should be removed. If the cystic duct is torn, its intes- 
tinal end must be closed and the gall-bladder removed. In rupture of either of the other 
ducts, simply provide for free drainage. 
The gall-bladder may become distended with bile in cases of obstruction of its duct or of the 
common bile-duct, or it may become distended from a collection of gall-stones within its interior, 
thus forming a large tumor. The swelling due to distention with bile is pear-shaped, and pro- 
jects downward and forward to the umbilicus. It moves with respiration, since it is attached to 
the liver. To relieve a patient of gall-stones, the gall-bladder must be opened and the gall-stones 
removed. The operation is performed by an incision two or three inches long in the right semi- 
lunar line, commencing at the costal margin. The peritoneal cavity is opened, and, the tumor 
having been found, gauze pads are packed around it to protect the peritoneal cavity, and it is 
aspirated. When the contained fluid has been evacuated the flaccid bladder is drawn out of 
the abdominal wound and its wall incised to the extent of an inch; any gall-stones in the 
bladder are now removed and the interior of the sac sponged dry. If the case is one of 
obstruction of the duct, an attempt must be made to dislodge the stone by manipulation through 
the wall of the duct; or it may be crushed from without by the fingers or carefully padded for- 
ceps. If this does not succeed, the safest plan is to incise the duct, extract the stone, close 1348 
THE ORGANS OF DIGESTION 
the incision in the duct by fine sutures in two layers and employ drainage. After all obstruction 
has been removed, four courses are open to the surgeon: 1. The wound in the gall-bladder 
may be at once sewed up, the organ returned into the abdominal cavity, and the external incision 
closed. 2. The edges of the incision in the gall-bladder may be sutured to the fascia of the ex- 
ternal wound, and a fistulous communication established between the gall-bladder and the exte- 
rior; this fistulous opening usually closes in the course of a few weeks. 3. The gall-bladder may 
be connected with the intestinal canal, preferably the duodenum, by means of a lateral anasto- 
mosis; this is known as cholecystenterostomy. 4. The gall-bladder may be completely removed 
(cholecystectomy). Plan 2 is usually followed. Plan 4 is employed when the coats of the 
gall-bladder are seriously diseased. Plan 2 is employed in obstruction of the common duct by 
malignant disease. 
If a stone blocks the diverticulum of Vater and if the common bile-duct and the pancreatic 
duct empty into the diverticulum, it is evident that both ducts will be blocked. It has been 
demonstrated that in such a case the pressure urging the bile onward is sufficient to overcome 
the pressure in the pancreatic duct and drive bile into the ducts of the pancreas, the result, 
perhaps, being disastrous inflammation of the pancreas. 
Septic trouble arises more rapidly when a stone is blocked in the duct than when stones merely 
block the gall-bladder, because the first-named part is richer in lymphatics (Murphy). 
THE PANCREAS (Figs. 958, 959, 960, 961). 
Dissection.-The pancreas may be exposed for dissection in three different ways: 1. By 
raising the liver, drawing down the stomach, and tearing through the gastro-hepatic omentum 
and the ascending layer of the transverse mesocolon. 2. By raising the stomach, the arch of 
the colon, and great omentum, and then dividing the inferior layer of the transverse mesocolon 
and raising its ascending layer. 3. By dividing the two layers of peritoneum, which descend 
from the great curvature of the stomach to form the great omentum; turning the stomach 
upward, and then cutting through the ascending layer of the transverse mesocolon (see Fig. 853). 
The Pancreas (^ay-x/>eaj, all flesh) is a compound racemose gland, analo- 
gous in its structure to the salivary glands, though softer and less compactly 
arranged than those organs. It is long and irregularly prismatic in shape, and 
has been compared to a human or a dog's tongue; it is of reddish-white color. 
Its right extremity being broad, is called the head. The right half of the head 
above is continuous with the neck, which connects the head to the main portion 
of the organ, the body. The neck is a slight constriction or thin part of the gland, 
placed in front of the portal vein, and connecting the head to the body. The left 
half of the head is separated from the neck by a notch, the incisura pancreaticus. 
The body of the gland gradually tapers into an extremity directed to the left, and 
called the tail. The pancreas is placed transversely across the posterior wTall of 
the abdomen, at the back of the epigastric and left hypochondriac regions. Its 
length varies from five to six inches, its breadth is an inch and a half, and its thick- 
ness from half an inch to an inch, being greater at its right extremity and along 
its upper border. Its weight varies from two to three and a half ounces, but it 
may reach six ounces. 
The Right Extremity or Head of the Pancreas (caput pancreatis) (Fig. 958) 
is shaped like the head of a hammer, being elongated both above and below; it 
is flattened from before backward, and conforms to the whole concavity of the 
duodenum, which is slightly overlapped by it. The anterior surface near its left 
border exhibits a notch, the incisura pancreatis, which contains the superior mesen- 
teric vessels. The notch marks the separation of the inferior portion of the head, 
which is known as the uncinate process of Winslow (processus uncinatus [IFinslowi]), 
which rests, below, upon the inferior portion of the duodenum, and, above, is 
pushed up back of the upper portion. The lower end of the head is crossed by 
the transverse colon and its mesocolon. Behind, the head of the pancreas is in 
relation with the inferior vena cava, the left renal vein, the right crus of the 
Diaphragm, and the aorta. The common bile-duct descends behind, between 
the duodenum and pancreas, or in the substance of the gland; and the pan- THE PANCREAS 
1349 
creatico-duodenal artery descends in front between the same parts. The head of 
the pancreas is closely adherent to the duodenum. 
Fig. 958.-The pancreas and its relations. 
Gastric artery. 
Lower end of oesophagus. 
Coeliac axis. 
i 
3 
k 
I 
m 
a 
b 
c 
d 
e 
J 
9 
Inferior mesenteric 
artery. 
Superior mesenteric 
artery. 
Spermatic vessels. 
Fig. 959.-The duodenum and pancreas. The liver has been lifted up and the greater part of the stomach 
removed: a, portal vein; b, hepatic duct; c, cystic duct; d, hepatic artery; e, right suprarenal capsule; 
f, pyloric orifice ; g, right gastro-epiploic artery ; h, superior mesenteric vein ; i, left crus of diaphragm ; j, left 
suprarenal capsule ; k, splenic vein ; I, splenic artery; m, duodeno-jejunal junction ; a, b, c, d, the four portions 
of the duodenum. (Testut.) THE ORGANS OF DIGESTION 
1350 
The Neck of the Pancreas is about an inch long, and passes upward and for- 
ward to the left, having the first part of the duodenum above it, and the ter- 
mination of the fourth portion below. It lies in front of the commencement of 
the portal vein, and is grooved on the right by the gastro-duodenal and superior 
pancreatico-duodenal arteries. The pylorus lies just above it. 
The Body (corpus pancreatis) and Tail (cauda pancreatis) of the Pancreas are 
somewhat prismatic in shape, and have three surfaces: anterior, posterior, and 
inferior. 
The Anterior Surface (facies anterior).-The anterior surface is somewhat con- 
cave, and is covered by the posterior surface of the stomach which rests upon it, 
the two organs being separated by the lesser sac of the peritoneum. At its right 
extremity there is a well-marked prominence, called by His the omental tuberosity 
(tuber omentale). 
The Posterior Surface (facies posterior).-The posterior surface is separated from 
the vertebral column by the aorta, the splenic vein, the left kidney and its vessels, 
the left suprarenal capsule, the pillars of the Diaphragm, and the origin of the 
superior mesenteric artery. 
The Inferior Surface (facies inferior) (Fig. 959).-The inferior surface is narrow, 
and lies upon the duodeno-jejunal flexure and on some coils of the jejunum; its left 
extremity rests on the splenic flexure of the colon. 
FIRST FOLD 
,OF DUODENUM 
ACCESSORY 
.PANCREATIC 
DUCT 
PANCREATIC 
DUCT 
COMMON 
BILE-DUCT 
SUPERIOR MESEN-' 
TERIC ARTERY 
SUPERIOR MESEN-' 
TERIC VEIN 
HEAD OFX 
PANCREAS 
BRANCH OF 
ACCESSORY 
DUCT 
Fig. 960.-The pancreas and duodenum from behind, with the pancreatic duct exposed. The superior 
mesenteric vessels are also shown in section, passing forward, surrounded by the recurved portion of the head of 
the pancreas. (Cunningham.) 
The Superior Border (margo superior) (Fig. 959).-The superior border of the 
body is blunt and flat to the right; narrow and sharp to the left, near the tail. It 
commences to the right in the omental tuberosity, and is in relation with the 
coeliac axis, from which the hepatic artery courses to the right just above the gland, 
while the splenic branch runs in a groove along this border to the left. 
The Anterior Border (margo anterior).-The anterior border is the position where 
the two layers of the transverse mesocolon separate; the one passing upward in 
front of the anterior surface, the other backward below the inferior surface 
(Fig. 853). 
The lesser end or tail of the pancreas is narrow; it extends to the left as far as 
the lower part of the inner aspect of the spleen, and its end is directed upward and 
to the left (Fig. 959). 
Birmingham describes the body of the pancreas as projecting forward as a 
prominent ridge into the abdominal cavity and forming a sort of shelf on which the 
stomach lies. He says: "The portion of the pancreas to the left of the middle line 
has a very considerable antero-posterior thickness; as a result the anterior surface 
is of considerable extent, it looks strongly upward, and forms a large and important 
part of the shelf. As the pancreas extends to the left toward the spleen it crosses 
the upper part of the kidney, and is so moulded on to it that the top of the kidney THE PANCREAS 
1351 
forms an extension inward and backward of the upper surface of the pancreas and 
extends the bed in this direction. On the other hand, the extremity of the pan- 
creas comes in contact with the spleen in such a way that the plane of its upper 
surface runs with little interruption upward and backward into the concave gastric 
surface of the spleen, which completes the bed behind and to the left, and, running 
upward, forms a partial cap for the wide end of the stomach."1 An occasional 
anomaly is a pancreas prolonged in front of the duodenum or actually embracing 
it (annular pancreas). 
Peritoneal Relations (Fig. 853).-The transverse mesocolon is attached to the 
anterior border of the pancreas, from the tail to the neck of the gland, and the two 
layers of the mesocolon separate. The anterior layer which comes from the lesser 
peritoneum covers part of the anterior surface and the superior surface; the poste- 
rior layer, which comes from the greater omentum, covers the rest of the anterior 
surface and the inferior surface. The posterior surface is devoid of peritoneum. 
RECTUS MUSCLE. 
Sth Costal Cartilage. 
7th Costal Cartilage. 
,7th Rib. 
■8th Rib. 
■9th Rib. 
'10th Rib. 
DIAPHRAGM. 
Abdominal Aorta. 
12th Rib. 
11th Rib. 
Fig. 961.-Transverse section through the middle of the first lumbar vertebra, showing the relations 
of the pancreas. (Braune.) 
There is in front of the head and at the anterior margin a narrow strip of panereas, 
which remains uncovered by peritoneum and which corresponds to the cellular 
tissue of the mesocolon. 
The principal excretory duct of the pancreas, called the pancreatic duct or canal 
of Wirsung (ductus pancreaticus [Wirsungi]) (Figs. 956, 958, and 960), from its 
discoverer, extends transversely from left to right through the substance of the 
pancreas. In order to expose it, the superficial portion of the gland must be 
removed. It commences by the junction of the small ducts of the lobules situated 
in the tail of the pancreas, and, running from left to right through the body, it con- 
stantly receives the ducts of the various lobules composing the gland. Consider- 
ably augmented in size, it reaches the neck, and turning obliquely downward, back- 
ward, and to the right, it comes into relation with the common bile-duct, lying to 
1 Journal of Anatomy and Physiology, vol. xxxi. part i. p. 102. 1352 
rlHE ORGANS OF DIGESTION 
its left side; leaving the head of the gland, it passes very obliquely through the 
mucous and muscular coats of the duodenum, and usually terminates by an orifice 
common to it and the ductus communis choledochus upon the summit of an ele- 
vated papilla, situated at the inner side of the descending portion of the duodenum, 
three or four inches below the pylorus (Figs. 954, 955, and 957). 
Sometimes the pancreatic duct and ductus communis choledochus open sepa- 
rately into the duodenum (Fig. 893). In about one-fifth of the subjects there is an 
accessory duct, which is given off from the canal of Wirsung in the neck of the pan- 
creas and passes horizontally to the right to open into the duodenum about an 
inch above the orifice of the main duct. This is known as the duct of Santorini 
(ductus pancreaticus accessorius [Santorini]) (Figs. 956, 957, and 960). 
The pancreatic duct, near the duodenum, is about the size of an ordinary quill; 
its walls are thin, consisting of two coats, an external fibrous and an internal 
mucous; the latter is smooth, and furnished near its termination with a few scat- 
tered follicles. 
Structure.-In structure, the pancreas resembles the salivary glands. It differs 
from them, however, in certain particulars, and is looser and softer in its texture. 
It is not enclosed in a distinct capsule, but is surrounded by areolar tissue, which 
dips into its interior, and connects together the various lobules of which it is com- 
posed. Each lobule, like the lobules of the salivary glands, consists of one of the 
ultimate ramifications of the main duct, terminating in a number of caecal pouches 
or alveoli, which are tubular and somewhat convoluted. The minute ducts con- 
nected with the alveoli are narrow and lined with flattened cells. They are the 
secreting end tubules. The narrow ducts which come from the end tubules are 
lined with flat epithelial cells. The alveoli are almost completely filled with secret- 
ing cells, so that scarcely any lumen is visible. In the centre of the end tubules 
flat cells are frequently found. They are continuations into the tubules of the 
duct epithelium. These cells are known as the centro-acinar cells of Langerhans. 
The true secreting cells which line the wall of the alveolus are very characteristic. 
They are columnar or rounded in shape and present two zones: an outer one 
clear and finely striated next the basement-membrane, and an inner granular 
one next the lumen. The highly refracting granules are known as zymogen 
granules. During digestion the granules gradually disappear and the cells become 
clear. During fasting the granular zone occupies more than one-half of the cell 
(Szymonowicz). In some secreting cells of the pancreas is a spherical mass, 
staining more easily than the rest of the cells; this is termed the paranucleus, and 
is believed to be an extension from the nucleus. The connective tissue among the 
gland tubules and alveoli presents in certain parts collections of cells, which are 
termed inter-alveolar cell-islets, intertubular cell-masses or islands of Langerhans. 
Opie points out that they are most common in the splenic end of the pancreas. 
The cells of the islands are smaller than the secreting cells of the alveoli, and 
are arranged in layers with intervening spaces. The islands are surrounded by 
fine connective tissue. The spaces in the islands contain capillaries. There 
are no ducts in the islands of Langerhans. Their function is to furnish the 
internal secretion of the pancreas. 
Blood-vessels, Lymphatics, and Nerves.-The arteries of the pancreas come from 
the superior pancreatico-duodenal branch of the gastro-duodenal; the inferior pan- 
creatico-duodenal branch of the superior mesenteric; the inferior pancreatic branch of 
the superior mesenteric; pancreatic branches of the hepatic and pancreatic branches 
of the splenic. In a few cases a large artery, the pancreatica magna, accompanies 
the pancreatic duct. In most cases there is no such vessel. The veins are the 
anterior pancreatico-duodenal branch of the superior mesenteric; the posterior pancre- 
atico-duodenal branch and other pancreatic branches of the portal; and pancreatic 
branches of the splenic. The lymphatics arise in a network about the lobules. THE SPLEEN 
1353 
Numerous collecting trunks pass to the surface of the pancreas, anastomose with 
each other, and enter into glands about the pancreas. The splenic glands receive 
most of the trunks. Others are received by glands along the aorta (Sappey), 
glands at the origin of the superior mesenteric artery, and glands along the pan- 
creatico-duodenal vessels.1 The nerves come from the coeliac, superior mesenteric, 
and splenic plexuses. 
The Pancreatic Juice.-The pancreatic juice is a clear, somewhat viscid alkaline 
liquid. Its specific gravity is about 1030. The solid matter consists chiefly of 
proteids, and amounts to about 10 per cent, of a sample of the juice.2 The juice 
contains a ferment which breaks up fat, a ferment which converts starch into 
sugar, a ferment which curdles milk, and a ferment which digests proteid material. 
Surface Form.-The pancreas lies in front of the second lumbar vertebra, and can some- 
times be felt, in emaciated subjects, when the stomach and colon are empty, by making deep 
pressure in the middle line about three inches above the umbilicus. 
Surgical Anatomy.-Of late years our knowledge of the structure, functions, and diseases 
of the pancreas has been notably increased, and surgeons have begun to operate for certain 
pancreatic diseases. It is occasionally the seat of cancer, which usually affects the head or 
duodenal end, and therefore often speedily involves the common bile-duct, leading to persistent 
jaundice. Cancer of the pancreas may be primary or secondary. Primary sarcoma is very 
unusual; secondary sarcoma is more common, but cancer is far commoner than either form of 
sarcoma. Adenoma may also occur. Cases are on record of the successful removal of tumors of 
the pancreas, but the operations are very dangerous, are extremely difficult, and are seldom 
attempted. The pancreas may be the seat of syphilitic or tuberculous disease. As a result of 
pancreatic injury, there may be effusion into the lesser peritoneal cavity. The lesser cavity 
becomes distended, and the fluid of this pseudo-cyst may contain pancreatic juice (Jordan Lloyd). 
True cysts of the pancreas are occasionally found. Pancreatic cysts may result from blocking 
of the duct, from epithelial proliferation, from traumatism and hemorrhage, or from hydatid dis- 
ease. Congenital cysts may occur, and cystic carcinoma is sometimes encountered. Cysts of the 
pancreas may present in the epigastric region above and to the right of the umbilicus. The 
fluid in these cysts contains some of the pancreatic secretion. A pancreatic cyst is best treated 
by opening the abdomen, suturing the cyst to the skin, opening the cyst and providing for drainage. 
Complete extirpation of the cyst is invariably difficult and is usually impossible. It has been 
said that the pancreas is the only abdominal viscus which has never been found in a hernial pro- 
trusion; but even this organ has been found, in company with other viscera, in rare cases of 
diaphragmatic hernia. The pancreas has been known to become invaginated into the intestine, 
and portions of tne organ have sloughed off. In cases of excision oj the pylorus great care must 
be exercised to avoid wounding the pancreas, as the escape of the pancreatic fluid may be attended 
with serious and even with fatal results, peritonitis and jat necrosis, and gangrene being caused. 
Rupture oj the pancreas as a solitary result of traumatism is very unusual, but is more common 
in violent injuries which rupture the liver and spleen as well. An injury which lacerates the 
pancreas and permits blood and pancreatic juice to flow into the lesser peritoneal cavity is usually 
rapidly fatal, but mav not be. The foramen of Winslow may be occluded by inflammation, and 
a pseudo-cyst may form. In severe laceration of the pancreas alone, it would be proper to open 
the abdomen, ligature bleeding vessels, suture the pancreas, and drain the lesser peritoneal cavity 
posteriorlv. A gunshot wound of the pancreas requires posterior drainage. Every effort must 
be made in a pancreatic wound to rapidly get rid of pancreatic fluid by drainage from the 
wound area, as this fluid is extremely irritant and may cause gangrene. 
I nffammation oj the pancreas is due to infection. Occasionally it seems to follow the entrance 
of bile into the pancreatic duct, because of plugging of the ampulla with a calculus (Halsted, 
Opie). Hemorrhage into the pancreas is frequent in acute pancreatitis, and fat necrosis is common 
in the fat of the mesentery, subperitoneal tissue, omentum, and other parts. Acute pancreatitis 
may be recovered from if the abdomen is opened, the pancreas incised, and drainage employed. 
In chronic interstitial pancreatitis of the head of the pancreas the gall-duct is apt to become 
blocked, and the disease is frequently mistaken for cancer. Cure may follow opening and drain- 
age of the gall-bladder. 
THE SPLEEN (LIEN) (Figs. 958. 959, 961). 
The spleen belongs to that class of bodies which are known as ductless glands. 
It is probably related to the blood-vascular system, but in consequence of its 
1 Poirier, Cun£o, and Delamare on the Lymphatics. Edited and translated by Cecil H. Leaf. 
2 Robson and Moyniham on Diseases of the Pancreas. 1354 
THE ORGANS OF DIGESTION 
anatomical relationship to the stomach and its physiological relationship to the 
liver it is convenient to describe it in this section. It is situated principally in the 
posterior portion of the left hypochondriac region, its upper and inner extremity 
extending into the epigastric region; lying between the fundus of the stomach 
and the Diaphragm. If the abdomen is opened a spleen of ordinary size is not 
visible from the front, as it is placed between the left kidney, Diaphragm, and 
stomach. It moves with the respiratory movements and with the movements of 
the stomach. It is the largest of the so-called ductless glands, and varies greatly 
in size. Usually it measures some five inches in length. It is of an oblong, 
flattened form, soft, of very brittle consistence, highly vascular, and of a dark- 
purplish color. 
Surfaces. The External or Phrenic Surface (facies diaphragmatica).-The exter- 
nal or phrenic surface is convex, smooth, and is directed upward, backward, and 
to the left, except at its upper end, where it is directed slightly inward. It is in 
relation with the under surface of the Diaphragm, which separates it from the 
eighth, ninth, tenth, and eleventh ribs of the left side, and in part from the lower 
border of the left lung and pleura. It is 
to be remembered that not only are the 
peritoneum and the Diaphragm between 
the spleen and the ribs, but also the cavity 
of the left pleura and a portion of the left 
lung. 
The Internal Surface.-The internal sur- 
face is concave, and divided by a ridge 
into an anterior or larger, and a posterior or 
smaller portion. 
'The Anterior Portion of the internal sur- 
face or the gastric surface {facies gastrica), 
which is directed forward and inward, is 
broad and concave, and is in contact with 
the posterior wall of the great end of the 
stomach; and below this with the tail of 
the pancreas. It presents near its inner 
border a long fissure, termed the hilum 
(hilus lienis). This is pierced by several 
irregular apertures, for the entrance and 
exit of vessels and nerves. 
The Posterior Portion of the internal 
surface or the renal surface (facies renalis) 
is directed inward and downward. It is 
somewhat flattened, does not reach as high 
as the gastric surface, is considerably narrower than the latter, and is in relation 
with the upper part of the outer surface of the left kidney and occasionally with 
the left suprarenal capside. 
The upper end of the spleen (extremitas superior) is directed inward, toward the 
vertebral column, where it lies on a level with the eleventh dorsal vertebra. The 
lower end (extremitas inf erior), sometimes termed the basal surface, is flat, triangular 
in shape, and rests upon the splenic flexure of the colon and the phreno-colic liga- 
ment, and is generally in contact with the tail of the pancreas. The anterior border 
(margo anterior) is free, sharp, and thin, and is often notched, especially below. It 
separates the phrenic surface from the gastric surface. The posterior border (margo 
posterior) is more rounded and blunter than the anterior. It separates the renal 
portion of the internal surface from the phrenic surface. It corresponds to the 
lower border of the eleventh rib and lies between the Diaphragm and left kidney. 
Fig. 962.-The spleen, showing its gastric and 
renal surfaces. (Testut.) THE SPLEEN 
1355 
The internal border is the name sometimes given to the ridge which separates the 
renal and gastric portions of the internal surface. 
The spleen is surrounded by peritoneum, except at the hilum and the serous 
membrane, is firmly adherent to its capsule, and is held in position by two folds 
of this membrane: one, the lieno-renal ligament (ligamentum phrenicolienale) (Figs. 
857 and 860), is derived from the layers of peritoneum forming the greater and 
lesser sacs, where they come into contact between the left kidney and the spleen. 
Between its two layers the splenic vessels pass; the second, the gastro-splenic 
omentum (ligamentum gastrolienale), also formed of two layers, derived from the 
greater and lesser sacs, respectively, where they meet between the spleen and 
stomach (Fig. 860). Between these two layers run the vasa brevia of the 
splenic artery and vein. The spleen is also supported by the phreno-colic ligament 
(ligamentum phrenicocolicum), upon which its lower end rests. 
The size and weight of the spleen are liable to very extreme variations at dif- 
ferent periods of life, in different individuals, and in the same individual under 
different conditions. In the adult, in whom it attains its greatest size, it is usually 
Fig. 963.-Transverse section of the spleen, showing the trabecular tissue and the splenic vein and 
its tributaries. 
about five inches in length, three inches in breadth, and an inch or an inch and a 
half in thickness, and weighs about seven ounces. At birth, its weight, in propor- 
tion to the entire body, is almost equal to what is observed in the adult, being as 
1 to 350; while in the adult it varies from 1 to 320 to 1 to 400. In old age, the organ 
not only decreases in weight, but decreases considerably in proportion to the 
entire body, being as 1 to 700. The size of the spleen is increased during and 
after digestion, and varies considerably according to the state of nutrition of the 
body, being large in highly fed, and small in starved animals. In intermittent 
and other fevers it becomes much enlarged, weighing occasionally from eighteen 
to twenty pounds. 
Frequently in the neighborhood of the spleen, and especially in the gastro- 
splenic and great omenta, small nodules of splenic tissue may be found, either 
isolated, or connected to the spleen by thin bands of splenic tissue. Every such 
nodule is known as a supernumerary or accessory spleen (lien accessorius'). Accessory 
spleens vary in size from that of a pea to that of a plum. THE ORGANS OF DIGESTION 
1356 
Support and Movability of the Spleen.-The spleen is normally movable 
within certain narrow limits. It moves with respiration and with stomach move- 
ments. It is supported by ligaments (p. 1355). An unduly movable spleen is 
called a movable spleen. In order that a spleen shall become unduly movable, 
the ligaments must stretch, and this stretching is often effected when the organ 
is greatly enlarged, but even an apparently normal spleen may become movable. 
Movable spleen is usually associated with movable left kidney. 
Structure.-The spleen is invested by two coats-an external serous and an 
internal fibro-elastic coat. 
The External or Serous Coat (tunica serosa).-The external or serous coat is 
derived from the peritoneum; it is thin, smooth, and in the human subject is inti- 
mately adherent to the fibro-elastic coat. It invests the entire organ, except at 
the places of its reflection on to the stomach and Diaphragm and at the hilum. 
The Fibro-elastic Coat (tunica albuginea).-The fibro-elastic coat forms the 
framework of the spleen. It is composed of connective tissue containing muscle- 
cells and elastic fibres, and it invests the organ as a capsule, and at the hilum is 
reflected inward upon the vessels in the form of sheaths. From these sheaths, as 
well as from the inner surface of the fibro-elastic coat, numerous small fibrous 
bands, trabeculae (trabeculae lienis) (Figs. 963 and 964), are given off in all direc- 
tions; these uniting, constitute the framework of the spleen. This framework 
resembles a sponge-like material, consisting of a number of small spaces or 
areolae formed by the trabeculae, which are given off from the inner surface of the 
capsule, or from the sheaths prolonged inwardly on the blood-vessels. The spaces 
or areolae contain the adenoid material known as splenic pulp (pulpa lienis). 
The proper coat, the sheaths of the vessels and the trabeculae, consist of a 
dense mesh of white and yellow elastic fibrous tissues, the latter decidedly pre- 
dominating. It is owing to the presence of this tissue that the spleen possesses 
a considerable amount of elasticity, which allows of the very great variations in 
size that it presents under certain circumstances. In addition to these con- 
stituents of this tunic, there is found in man a small amount of non-striped mus- 
cular fibre, and in some mammalia (e. g., dog, pig, and cat) a very considerable 
amount, so that the trabeculae appear to consist chiefly of muscular tissue. It is 
probably because of this muscular structure that the spleen exhibits, when acted 
upon by the galvanic current, faint traces of contractility. 
The proper substance of the spleen or splenic-pulp is a soft mass of a dark 
reddish-brown color, resembling grumous blood. When a thin section is exam- 
ined under a microscope, it is found to consist of a number of branching 
cells and an intercellular substance. The cells are connective-tissue corpuscles, 
and have been named the sustentacular or supporting cells of the pulp. The 
processes of these branching cells communicate with each other, thus forming a 
delicate reticulated tissue in the interior of the areolae formed by the trabeculae of 
the capsule; so that each primary space may be considered to be divided into a 
number of smaller spaces by the junction of these processes of the branching 
corpuscles. These secondary spaces contain blood, in which, however, the white 
corpuscles are found to be in larger proportions than in ordinary blood. The 
sustentacular cells are either small uni-nucleated or larger multi-nucleated cells; 
they do not stain deeply with carmine, like the cells of the Malpighian 
bodies, presently to be described (W. Muller), but like them they possess aime- 
boid movements (Cohnheim). In many of them may be seen deep red or 
reddish-yellow granules of various sizes which present the characters of the 
hsematin of the blood. Sometimes, also, unchanged blood-disks are seen included 
in these cells, but more frequently blood-disks are found which are altered both 
in form and color. In fact, blood-corpuscles in all stages of disintegration may 
be noticed to occur within them. Klein has recently pointed out that sometimes THE SPLEEN 
1357 
these cells in the young spleen contain a proliferating nucleus; that is to say, 
the nucleus is of large size, and presents a number of knob-like projections, 
as if small nuclei were budding from it by a process of gemmation. This obser- 
vation is of importance, as it may explain one possible source of the colorless 
blood-corpuscles. 
The interspaces or areolae formed by the framework of the spleen are thus filled 
by a delicate reticulum of branched connective-tissue corpuscles, the interstices of 
which are occupied by blood, and in which the blood-vessels terminate in the 
manner now to be described. 
Blood-vessels of the Spleen.-The splenic artery (Fig. 961) is remarkable for its 
large size in proportion to the size of the organs, and also for its tortuous course. 
It divides into six or more branches, which enter the hilum of the spleen and 
ramify throughout its substance, receiving sheaths from the involution of the 
external fibrous tissue. Similar sheaths also invest the nerves and veins. 
Each branch runs in the transverse axis of the organ from within outward, 
diminishing in size during its transit, and giving off in its passage smaller branches, 
some of which pass to the anterior, others to the posterior part. These ultimately 
Fig. 964.-Transverse section of the human spleen, showing the distribution of the splenic artery 
and its branches. 
leave the trabecular sheaths, and terminate in the proper substance of the spleen 
in small tufts or pencils of minute arterioles, which open into the interstices 
of the reticulum formed by the branched sustentacular cells (Figs. 964, 965, and 
966). Each of the larger branches of the artery supplies chiefly that region of the 
organ in which the branch ramifies, having no anastomosis with the majority 
of the other branches. 
The arterioles (Fig. 966), supported by the minute trabeculae, traverse the pulp 
in all directions in bundles or pencilli of straight vessels. Their external coat, on 
leaving the trabecular sheaths, consists of ordinary connective tissue, but it grad- 
ually undergoes a transformation, becomes much thickened, and is converted into 
a lymphoid material? This change is effected by the conversion of the con- 
nective tissue into a lymphoid tissue, the bundles of connective tissue becoming 
looser and laxer, their fibrils more delicate, and containing in their interstices 
an abundance of lymph-corpuscles (W. Muller). This lymphoid material is sup- 
plied with blood by minute vessels derived from the artery with which they are 
1 According to Klein, it is the sheath of the small vessel which undergoes this transformation, and forms a 
" solid mass of adenoid tissue which surrounds the vessel like a cylindrical sheath." (Atlas of Histology, p. 424.) 1358 
THE ORGANS OF DIGESTION 
in contact, and which terminates by breaking up into a network of capillary 
vessels. 
The altered coat of the arterioles, consisting of lymphoid tissue (Fig. 966), pre- 
sents here and there thickenings of a spheroidal shape, the Malpighian bodies of the 
spleen (noduli lymphatici lienales [Malpigha}) (Fig. 965). These bodies vary in size 
from about the of an inch to the of an inch in diameter. They are merely 
local expansions or hyperplasiae of the lymphoid tissue of which the external coat of 
the smaller arteries of the spleen is formed. They are most frequently found sur- 
rounding the arteriole, which thus seems to tunnel them, but occasionally they grow 
from one side of the vessel only, and present the appearance of a sessile bud grow- 
ing from the arterial wall. Klein, however, denies this, and says it is incorrect to 
describe the Malpighian bodies as isolated masses of adenoid tissue, but that they 
are always formed around an artery, though there is generally a greater amount on 
one side than on the other, and that, therefore, in transverse sections the artery in 
the majority of cases is found in an eccentric position. These bodies are visible to 
the naked eye on the surface of a fresh section of the organ, appearing as minute 
dots of semi-opaque whitish color in the dark 
substance of the pulp. In minute structure they 
resemble the adenoid tissue of lymphatic glands, 
consisting of a delicate reticulum in the meshes 
of which lie ordinary lymphoid cells. 
'rhe reticulum of the tissue is made up of ex- 
tremely delicate fibrils, and is comparatively 
open in the centre of the corpuscle, becoming 
closer at the periphery of the body. The cells 
which it encloses, like the supporting cells of the 
pulp, are possessed of amoeboid movements, but 
when treated with carmine become deeply 
stained, and can thus easily be recognized from 
those of the pulp. 
'Fhe arterioles terminate in capillaries, which 
traverse the pulp in all directions; their walls 
become much attenuated, lose their tubular 
character, and the cells of the lymphoid tissue 
of which they are composed become altered; presenting a branched appearance 
and acquiring processes which are directly connected with the processes of the 
sustentacular cells of the pulp (Fig. 966). In this manner the capillary vessels 
terminate, and the blood flowing through them finds its way into the interstices 
of the reticulated tissue formed by the branched connective-tissue corpuscles of 
the splenic pulp, 'rims the blood passing through the spleen is brought into 
intimate relation with the elements of the pulp, and no doubt undergoes important 
changes. 
After these changes have taken place the blood is collected from the interstices 
of the tissue by the rootlets of the veins (Fig. 963), which commence much in the 
same way as the arteries terminate. Where a vein is about to originate the con- 
nective-tissue corpuscles of the pulp arrange themselves in rows in such a way as to 
form an elongated space or sinus. They become changed in shape, being elongated 
and spindle-shaped, and overlap each other at their extremities. They thus form 
a sort of endothelial lining of the path or sinus, which is the radicle of a vein. 
On the outer surface of these cells are seen delicate transverse lines or markings 
which are due to minute elastic fibrillae arranged in a circular manner around the 
sinus. Thus the channel obtains a continuous external investment, and grad- 
ually becomes converted into a small vein, which after a time presents a coat of 
ordinary connective tissue, lined by a layer of fusiform endothelial cells which are 
Fig. 965.-Part of a Malpighian body 
of the spleen of man. a, arterial branch 
in longitudinal section ; b, adenoid tissue, 
still containing the lymph-corpuscles ; only 
their nuclei are shown ; r, adenoid reticu- 
lum, the lymph-corpuscles accidentally re- 
moved. (Klein and Noble Smith.) THE SPLEEN 
1359 
continuous with the supporting cells of the pulp. The smaller veins unite to form 
larger ones which do not accompany the arteries, but soon enter the trabecular 
sheaths of the capsule, and by their junction form from six or more branches which 
emerge from the hilum and, uniting, form the splenic vein, the largest radicle of 
the portal vein (Figs. 958 and 962). 
The veins are remarkable for their numerous anastomoses, while the arteries 
hardly anastomose at all. 
The lymphatics originate in two ways-i .e., from the sheaths of the arteries 
and in the trabeculae. The former trunks are the deep collecting trunks, and 
Supporting cell. 
Vessel undergoing lymphoid change. 
Vessel continuous 
with processes of 
supporting cells. 
Small 
artery. 
Supporting cell. 
Supporting, 
cell. 
Fig. 966.-Section of spleen, showin? the termination of the small blood-vessels. 
accompany the blood-vessels; the latter pass to the superficial lymphatic plexus, 
which may be seen on the surface of the organ. The two sets communicate in 
the interior of the organ. The deep trunks at the hilum number from five to 
ten, and terminate in the splenic glands. The superficial trunks also pass to the 
hilum and terminate in the splenic glands. 
The nerves are derived from the splenic plexus, which is part of or connected 
with the solar plexus. The nerves enter the spleen with the vessels. 
Surface Form.-The spleen is situated under cover of the ribs of the left side, being sepa- 
rated from them by the Diaphragm, and above by a small portion of the lower margin of the 
left lung and pleura. Its position corresponds to the eighth, ninth, tenth, and eleventh ribs. 
It is placed very obliquely. " It is oblique in two directions- viz., from above downward and 
outward, and also from above downward and forward" (Cunningham). " Its highest and 
lowest points are on a level respectively with the ninth dorsal and first lumbar spines; its inner 
end is distant about an inch and a half from the median plane of the body, and its outer end 
about reaches the mid-axillary line" (Quain). 
Surgical Anatomy.-Injury of the spleen is less common than that of the liver, on account 
of its protected situation and connections. It may be ruptured by direct or indirect violence, 
torn by a broken rib, or injured by a punctured or gunshot wound. When the organ is enlarged 
the chance of rupture is increased. The great risk is hemorrhage, owing to the extreme vascu- 
larity of the organ, and the absence of a proper system of capillaries. The injury is not, how- 
ever, necessarily fatal, and this would appear to be due in a great measure to the contractile 
power of its capsule, which narrows the wound and thus antagonizes the escape of blood. In 
cases in which the symptoms suggest such an injury and indicate danger to life, laparotomy must 
be performed; and if the hemorrhage cannot be arrested by ordinary surgical methods the spleen 
must be removed. The spleen may become displaced, producing great pain from stretching of 
the vessels and nerves, and this dislocation may render necessary removal of the organ. The 
spleen may become enormously enlarged in certain diseased conditions, such as ague, leukaemia, 
syphilis, valvular disease of the heart, or without any obtainable history of previous disease. 
It may also become enlarged in lymphadenoma as a part of a general blood disease. In these 
cases the mass may fill the abdomen and extend into the pelvis, and may be mistaken for 
ovarian or uterine disease. 1360 
THE ORGANS OF DIGESTION 
The spleen is sometimes the seat of cystic tumors, especially hydatids, and of abscess. These 
cases require treatment by incision and drainage; and in abscess great care must be taken if 
there are no adhesions between the spleen and abdominal cavity, to prevent the escape of any 
of the pus into the peritoneal cavity. If possible, the operation should be performed in two 
stages. Sarcoma and carcinoma are occasionally found in the spleen, but very rarely as a primary 
disease. In movable spleen, if the organ is normal, follow the advice of Rydygier and loosen 
the parietal peritoneum to make a pocket, place the spleen in the pocket, and pass sutures through 
the parietal peritoneum and the splenic ligaments. A movable diseased spleen should be removed. 
Extirpation of the spleen has been performed for wounds or injuries, floating spleen, simple 
hypertrophy, and leukaemic enlargement; but in the latter case the operation is now regarded 
as unjustifiable, as it is practically certain to terminate fatally. The incision is best made in 
the left semilunar line: the spleen is isolated from its surroundings, and the pedicle transfixed 
and ligatured in two portions, before the tumor is turned out of the abdominal cavity, if this is 
possible, so as to avoid any traction on the pedicle, which may cause tearing of the splenic vein and 
which inevitably induces grave shock. In applying the ligatures the surgeon must not include 
the tail of the pancreas, and in lifting out the organ care must be taken to avoid rupturing the 
capsule. THE ORGANS OF VOICE AND RESPIRATION 
THE LARYNX. 
THE Larynx is the organ of voice, placed at the upper part of the air-passage. 
It is situated between the trachea and base of the tongue, at the upper and 
forepart of the neck, where it forms a considerable projection in the middle line. 
On either side of it lie the great vessels of the neck; behind, it forms part of the 
boundary of the pharynx, and is covered by the mucous membrane lining that 
cavity. Its vertical extent corresponds to the fourth, fifth, and sixth cervical ver- 
tebrae, but it is placed somewhat higher in the female and also during childhood. 
In infants between six and twelve months of age Symington found that the tip of 
HYOID 
BONE' 
THYROID, 
CARTILAGE 
OESOPHAGUS- 
TRACHEA- 
STE R N O-TH Y ROI D. 
MUSCLE 
THYROID. 
GLAND 
THYROID 
BRANCH OF" 
CEPHALIC 
ARTERY 
STERNUM' 
ASCENDING- 
AORTA 
Fig. 967.-Sagittal section of a man twenty-one years of age. (After W. Braune.) 
the epiglottis was a little above the level of the cartilage between the odontoid 
process and body of the axis, and that between infancy and adult life the larynx 
descends for a distance equal to two vertebral bodies and two intervertebral disks. 
The movements of the head affect the position of the larynx. When the head is 
drawn back, the larynx is lifted, and when the chin approaches the chest the 
larynx is depressed. During swallowing the larynx moves distinctly; during sing- 
ing it moves slightly. The larynx is suspended by the stylo-hyoid ligament, the 
1361 1362 
THE ORGANS OE VOICE AND RESPIRATION 
muscles of the upper border of the hyoid bone, the Stylo-pharyngeus and Palato- 
pharyngeus muscles. According to Sappey, the average measurements of the adult 
larynx are as follows: 
Vertical diameter 
In males. 
44 mm. 
In females. 
36 mm. 
Transverse diameter 
. 43 " 
41 " 
Antero-posterior diameter 
. 36 " 
26 " 
Circumference 
. 136 " 
112 " 
Until puberty there is no marked difference between the larynx of the male 
and that of the female. In the latter its further increase in size is only slight, 
whereas in the former it is great; all the cartilages are enlarged, and the thyroid 
becomes prominent as the pomum Adami in the middle line of the neck, while 
the length of the glottis is nearly doubled. 
The larynx is broad above, where it presents the form of a triangular box, 
flattened behind and at the sides, and bounded in front by a prominent vertical 
ridge. Below, it is narrow and cylindrical. It is composed of cartilages, which 
are connected together by ligaments and moved by numerous muscles. It is lined 
by mucous membrane, which is continuous above with that lining the pharynx and 
below with that of the trachea. 
In the median line of the neck the larynx has in front of it the skin and cer- 
vical fascia. There is often a bursa between the skin and fascia over the most 
prominent part of the larynx. It is called the bursa subcutanea prominentiae 
laryngeae. It is present particularly in men, and is seldom found in the 
young or in women. The larynx is covered to each side by the thyroid gland, 
and the Sterno-hyoid, Sterno-thyroid, Thyro-hyoid, and Omo-hyoid muscles, and 
the Inferior constrictors of the pharynx. Posterior is the laryngeal portion of the 
pharynx. 
The Cartilages of the Larynx (cartilagines laryngis).-The cartilages of the 
larynx are nine in number, three single, and three pairs: 
Thyroid. 
Cricoid. 
Epiglottis 
Two Arytenoid. 
Two Comicula Laryngis. 
Two Cuneiform. 
The Thyroid Cartilage (cartilago thyreoidea) (Figs. 968 and 969).-The thyroid 
cartilage (from d^pzbz, a shield) is hyaline cartilage and is the largest cartilage 
of the larynx. It is at the anterior and upper portion of the larynx. It con- 
sists of two lateral lamellae or alae, united at an acute angle in front, forming a 
vertical projection in the middle line, which is prominent above and called the 
pomum Adami (prominentia laryngea). This projection is subcutaneous, is more 
distinct in the male than in the female, and is often separated from the integu- 
ment by a bursa, the bursa subcutanea prominentiae laryngeae. 
Each lamella is quadrilateral in form. Its outer surface (Fig. 968) presents 
an oblique ridge (linea obliqua), which passes downward and forward from a 
tubercle situated near the root of the superior cornu, the superior tubercle (tuber- 
culum thyreoideum superius), to a small tubercle near the anterior part of the 
lower border, the inferior tubercle (tuberculum thyreoideum inferius). This ridge 
gives attachment to the Sterno-thyroid and Thyro-hyoid muscles, and the portion 
of cartilage included between it and the posterior border gives attachment to 
part of the Inferior constrictor muscle. Just below each superior tubercle there 
is often an opening, the thyroid foramen (foramen thyreoideum). 
The anterior borders of the alae of the thyroid cartilage which are continuous 
below are separated above by a V-shaped notch, the thyroid notch (incisura thy- 
reoidea [superior]). THE LARYNX 
1363 
1 he Inner Surface (Fig. 969) of each ala is smooth, slightly concave, and 
covered by mucous membrane above and behind; but in front, in the receding 
angle formed by their junction, are attached the epiglottis, the true and false 
vocal cords, the Thyro-arytenoid and Thyro-epiglottidean muscles, and the 
thyro-epiglottidean ligament. 
The Upper Border or Margin of the Thyroid Cartilage (Fig. 969) is sinuously curved, 
being concave at its posterior part, just in front of the superior cornu, then rising 
into a convex outline, which dips in front to form the sides of the thyroid notch, 
in the middle line, immediately above the pomum 
Adami. This border gives attachment through- 
out its whole extent to the thyro-hyoid or hyo- 
thyroid membrane (membrana hyot hyr eoidea). 
The Lower Border or Margin (Fig. 969) is nearly 
straight in front, but behind, close to the cornu, 
it is concave. It is connected to the cricoid cartil- 
age, in and near the median line, by the middle 
portion of the crico-thyroid membrane (membrana 
cricothyreoidea); and, on either side, by the 
Crico-thyroid muscle. 
The Posterior Borders (Fig. 969) are thick and 
rounded, and each terminates above, in a superior 
cornu (cornu superius), and below, in an inferior 
cornu (cornu injerius). The two superior cornua 
are long and narrow, directed upward, backward, 
and inward, and terminate in conical extremities, 
which give attachment to the lateral thyro-hyoid 
ligaments. The two inferior cornua are short 
and thick; they pass downward, with a slight in- 
clination forward and inward, and each presents 
on its inner surfaces a small oval articular facet 
for articulation with the side of the cricoid cartil- 
age (Fig. 968). The posterior border receives the 
insertion of the Stylo-pharyngeus and Palato-pharyngeus muscles on each side. 
During infancy the alae of the thyroid cartilage are joined to each other by a 
narrow, lozenge-shaped strip, named the intrathyroid cartilage. This strip extends 
from the upper to the lower border of the thyroid cartilage in the middle line, 
and is distinguished from the alae by being more transparent and more flexible. 
The Cricoid Cartilage (cartilago cricoidea) (Figs. 968, 969, and 971).-The cri- 
coid cartilage is so called from its resemblance to a signet ring (xpixoQ, a ring). 
It is smaller, but thicker and stronger than the thyroid cartilage, and forms the 
lower and back part of the cavity of the larynx. It is hyaline cartilage and con- 
sists of two parts: a quadrate portion, situated behind, and a narrow ring or 
arch, one-fourth or one-fifth the depth of the posterior part, situated in front. 
The posterior square portion rapidly narrows at the sides of the cartilage, at the 
expense of the upper border, into the anterior portion. 
Its Posterior Portion or Lamina (lamina cartilaginis cricoidcae) is very deep and 
broad, and measures from above downward about an inch (2 to 3 cm.); it presents, 
on its posterior surface, in the middle line, a vertical ridge for the attachment of 
the longitudinal fibres of the oesophagus; and on either side a broad depression 
for the Crico-arytenoideus posticus muscle. 
Its Anterior Portion or Arcus (arcus cartilaginis cricoideae) is narrow and convex, 
and measures vertically about one-fourth or one-fifth of an inch (5 to 7 cm.); 
it affords attachment externally in front and at the sides to the Crico-thyroid 
muscles, and, behind, to part of the Inferior constrictor. 
Fig. 968.-Side view of the thyroid 
and cricoid cartilages. 1364 
THE ORGANS OF VOICE AND RESPIRATION 
At the point of junction of the posterior quadrate portion with the rest of the 
cartilage is a small round elevation, for articulation with the inferior cornu of the 
thyroid cartilage. 
The Lower Border of the cricoid cartilage is horizontal, and connected to the 
upper ring of the trachea by fibrous membrane (Figs. 968 and 970). 
Its Upper Border is directed obliquely upward and backward, owing to the 
great depth of the posterior surface. It gives attachment, in front, to the middle 
portion of the crico-thyroid mem- 
brane ; at the sides, to the lateral 
portion of the same membrane 
and to the lateral Crico-arytenoid 
muscle; behind, it presents, in the 
middle, a shallow notch, and on 
each side of this is a smooth, oval 
surface, directed upward and out- 
ward, for articulation with the 
arytenoid cartilage. 
The Inner Surface of the cricoid 
cartilage is smooth, and lined with 
mucous membrane. 
The Arytenoid Cartilages (cartil- 
agines arytaenoideae) (Figs. 969, 
972, and 976).- The arytenoid 
cartilages are so called from the 
resemblance they bear, when ap- 
proximated, to the mouth of a 
pitcher (apurcuva, a pitcher). They 
are two in number, and situated 
at the upper border of the cricoid 
cartilage, at the back of the larynx 
in the interval between the poste- 
rior borders of the alae of the thy- 
roid cartilages. Each cartilage is 
in form a three-sided pyramid, and 
presents for examination three sur- 
faces, a base, and an apex. 
The Posterior Surface is trian- 
gular, smooth, concave, and gives 
attachment to the transverse por- 
tion of the Arytenoid muscle. 
The Anterior or External Surface 
is somewhat convex and rough. It 
presents, near its apex, a small 
elevation, the colliculus; from this a 
ridge (crista arcuata) passes back- 
ward and then forward and down- 
ward into a sharp-pointed process, the vocal process. This ridge separates a 
deep depression above, the fovea triangularis, from a broader and shallower depres- 
sion below, the fovea oblonga. A short distance above the base a small tubercle 
gives origin to the ligament of the false vocal cord, the superior thyro-arytenoid 
ligament. To the outer part of the ridge, as well as the surface above and below, 
is attached the Thyro-arytenoid muscle. 
The Internal Surface is narrow, smooth, and flattened, covered by mucous 
membrane, and forms the lateral boundary of the respiratory part of the glottis. 
Epiglottis. 
11Xa} 91 
Thyroid. 
Vjuer ma>Wn 
Cornicula laryngis. 
Cuneiform cartilage. 
Arytenoid. 
Insertion of 
CRICO-ARYTENOIDEUS 
POSTICUS ET LATERALIS. 
Posterior 
surface. 
Arytenoid cartilages, base. 
Cricoid. 
Articular facet for 
arytenoid cartilage. 
Articular facet for 
inferior cornu of 
thyroid cartilage. 
Fig. 969.-The cartilages of the larynx. Posterior view. THE LARYNX 
1365 
The Base (basis) of each cartilage is broad, and presents a concave smooth sur- 
face, for articulation with the cricoid cartilage. Two of its angles require special 
mention: the external angle, which is short, rounded, and prominent, projects 
backward and outward, and is termed the muscular process (processus muscularis), 
from receiving the insertion of the Posterior and Lateral crico-arytenoid muscles. 
The anterior angle, also prominent, but more pointed, projects horizontally forward, 
and gives attachment to the inferior thyro-arytenoid ligament, the supporting liga- 
ment of the true vocal cord. This angle is called the vocal process (processus vocalis). 
The Apex of each cartilage is pointed, curved backward and inward, and sur- 
mounted by a small conical, cartilaginous-nodule, the corniculum laryngis, articu- 
lated with or united to the arytenoid cartilage. 
The Cornicula Laryngis or Cartilages of Santorini (cartilagines corniculatae) (Figs. 
969 and 975).-The cornicula laryngis are two small conical nodules, consisting of 
white fibro-cartilage, which articulate with the summit of the arytenoid cartilages 
and serve to prolong them backward and inward. To them are attached the aryteno- 
epiglottidean folds. They are sometimes united to the arytenoid cartilages. 
The Cuneiform Cartilages or Cartilages of Wrisberg (cartilagines cuneijormes) 
(Figs. 969 and 971).--The cuneiform cartilages are two small, elongated, cartil- 
aginous bodies, placed one on each side, in the fold of mucous membrane which 
extends from the apex of the arytenoid cartilage to the side of the epiglottis, and is 
called the aryteno-epiglottidean fold (plica aryepiglottica) (Fig. 971); they give 
rise to small whitish elevations on the inner surface of the mucous membrane, 
just in front of the arytenoid cartilages. 
The Epiglottis or the Cartilage of the Epiglottis (cartilago epiglottica) (Figs. 967,969, 
970, 971, 972, and 975).-The epiglottis is a thin, flexible lamella of fibro-cartilage, 
of a yellowish color, shaped like a leaf, and placed behind the tongue in front of 
the superior opening of the larynx. Its free extremity, which is directed upward, 
is broad and rounded, and often notched; its attached part (petiolus epiglottidzs) 
is long, narrow, and connected to the receding angle between the alae of the 
thyroid cartilage, just below the median notch, by a long, narrow ligamentous 
band, the thyro-epiglottic ligament (ligamentum thyreoepiglotticum) (Fig. 972). It 
is also connected to the posterior surface of the body of the hyoid bone by an 
elastic ligamentous band, the hyo-epiglottic ligament (ligamentum hyoepiglotticum). 
Its Anterior or Lingual Surface is curved forward, toward the tongue, and cov- 
ered at its upper, free part by mucous membrane, which is reflected on to the 
sides and base of the organ, forming a median and two lateral folds, the glosso- 
epiglottidean folds (plicae glossoepiglotticae) (Fig. 971). The median glosso-epiglot- 
tidean fold (plica glossoepiglottica mediana) contains the elastic glosso-epiglottic 
ligament (ligamentum glossoepiglotticum). Each lateral glosso-epiglottidean fold 
(plica glossoepiglottica lateralis) runs from the front and side of the base of the 
epiglottis to the side of the tongue. The depression between the epiglottis and 
the base of the tongue on each side of the median fold is named the vallecula 
epiglottica. The lower part of the anterior surface of the epiglottis lies behind the 
hyoid bone, the thyro-hyoid membrane, and upper part of the thyroid cartilage, 
but is separated from these structures by a mass of fatty tissue. 
Its Posterior or Laryngeal Surface is smooth, concave from side to side, concavo- 
convex from above downward; its lower part projects backward as an elevation, 
the tubercle or cushion (tuberculum epiglotticum) (Fig. 970); when the mucous mem- 
brane is removed, the surface of the cartilage is seen to be studded with a number 
of small mucous glands, which are lodged in little pits upon its surface. To its 
sides the aryteno-epiglottidean folds (plicae aryepiglotticae) are attached (Fig. 971). 
Structure.-The cuneiform cartilages, the epiglottis, and the apices of the 
arytenoids are composed of yellow elastic cartilage, which shows little tendency to 
calcification; on the other hand, the thyroid, cricoid, and the greater part of the 1366 
THE ORGANS OF VOICE AND RESPIRATION 
arytenoids consist of hyaline cartilage, and become more or less ossified as age 
advances. Ossification commences about the twenty-fifth year in the thyroid car- 
tilage, somewhat later in the cricoid and arytenoids; by the sixty-fifth year these 
cartilages may be completely converted into bone. The cornicula laryngis consist 
of white fibro-cartilage, which becomes osseous about the seventieth year. 
Ligaments, Joints, and Membranes of the Larynx.-The ligaments of the larynx 
are extrinsic-i. e., those connecting the thyroid cartilage and epiglottis with the 
hyoid bone, and the cricoid cartilage with the trachea; and intrinsic, those which 
connect the several cartilages of the larynx to each other. 
The ligaments connecting the thyroid cartilage with the hyoid bone are three 
in number-the thyro-hyoid membrane, and the two lateral thyro-hyoid ligaments. 
The Thyro-hyoid or Hyo-thyroid Membrane or Ligament (membrana hyothyreoidea) 
(Fig. 972) is a broad, fibro-elastic, membranous layer, attached below to the 
upper border of the thyroid cartilage, and above to the posterior border of the 
body and greater cornua of the hyoid bone, passing behind the postero-inferior 
surface of the hyoid, and being separated from this surface by a synovial bursa 
(bursa m. sternohyoidei), which facilitates the upward movement of the larynx 
during deglutition. The membrane is thicker in the middle line than at either 
side. This thickening is due to elastic fibres, and constitutes the middle thyro- 
hyoid ligament (ligamentum hyothyreoideum medium). On each side the posterior 
extremity of the membrane is thickened by elastic fibres, constituting the lateral 
thyro-hyoid ligament (ligamentum hyothyreoideum laterale). The thyro-hyoid 
membrane is pierced on each side by the superior laryngeal vessels and the 
internal laryngeal nerve. The anterior surface of the thyro-hyoid membrane is 
in relation with the Thyro-hyoid, Sterno-hyoid, and Omo-hyoid muscles and with 
the body of the hyoid bone. The two lateral ligaments are rounded, elastic cords, 
which pass between the superior cornua of the thyroid cartilage and the extremi- 
ties of the greater cornua of the hyoid bone. A small cartilaginous nodule (car- 
tilago triticea), sometimes bony, is frequently found in each. 
The Membrana Quadrangularis is an elastic membrane containing numerous 
glands. The fibres of the membrane run in part downward and in part down- 
ward and backward. The membrane on each side arises in front and above at 
the lateral margin of the cartilage of the epiglottis, below at the posterior surface 
of the angle of the thyroid cartilage and becomes attached behind to the cornicula 
laryngis and to the inner margins of the arytenoid cartilages.1 The membranes 
converge below and medianward. The ligamentum ventriculare is the superior 
end of the membrane (Spalteholz). The fibres constituting the ligamentum ven- 
triculare are given off at the thyroid cartilage above the ligamentum vocale and 
pass horizontally backward to the medial margin of the fovea triangularis of the 
arytenoid cartilage.2 The epiglottis is connected to the tongue by the three 
glosso-epiglottidean folds of mucous membrane, which may also be considered 
as extrinsic ligaments of the epiglottis. 
The Glosso-epiglottidean Folds or Ligaments (plicae epiglotticae) (Fig. 971) num- 
ber three. The middle glosso-epiglottidean fold (plica glossoepiglottica mediana) 
passes from the middle of the anterior free surface of the epiglottis to the base 
of the tongue. It contains the glosso-epiglottic ligament. The lateral glosso- 
epiglottidean or the pharyngo-epiglottidean fold (plica glossoepiglottica lateralis) 
on each side passes from the side of the epiglottis to the side of the base of the 
tongue and to the pharyngeal wall. On each side between the median and lateral 
folds is a depression, the vallecula epiglottica. 
The Hyo-epiglottic Ligament ((ligamentum hyoepiglotticum) is an elastic band, 
which extends from the anterior surface of the epiglottis, near its apex, to the 
' Hand Atlas of Human Anatomy. By Werner Spalteholz. Translated and edited by Lewellys F. Barker. 
5 Spalteholz's Hand Atlas of Human Anatomy. Translated and edited by Lewellys F. Barker. THE LARYNX 
1367 
upper border of the body of the hyoid bone. The epiglottis is attached to the 
thyroid cartilage, below and behind the superior thyroid notch, by the strong 
and elastic thyro-epiglottic ligament (tigamentum thyreoepiglotticum) (Fig. 972). 
Between the epiglottis, the hyo-epiglottic ligament and the thyro-hyoid membrane 
is a triangular space containing fat on each side of the median line. 
The ligaments connecting the thyroid cartilage to the cricoid are also three in 
number-the crico-thyroid membrane and the capsular ligaments. 
The Crico-thyro id Membrane (conus elastic us) (Figs.968 and 975) is an elastic mem- 
brane which passes radially from the posterior surface of the angle of the thyroid 
cartilage to the upper margin of the arch of the cricoid cartilage and to the vocal 
processes of the arytenoid cartilages. It is composed mainly of yellow elastic 
tissue. It consists of three parts, a central triangular portion and two lateral 
portions. The central part (tigamentum cricothyreoideum medium) is thick and 
strong, narrow above and broadening out below. It connects together the con- 
tiguous margins of the thyroid and cricoid cartilages. It is convex, concealed on 
each side by the Crico-thyroid muscle, but subcutaneous in the middle line; it is 
crossed horizontally by a small anastomotic arterial arch, formed by the junction 
of the two crico-thyroid arteries. The lateral portions are thinner and lie close 
under the mucous membrane of the larynx. They extend from the superior 
border of the cricoid cartilage to the inferior margin of the true vocal cords with 
which they are continuous. On each side are the uppermost fibres from the 
inferior thyro-arytenoid ligament (tigamentum vocale). 
The lateral portions are lined internally by mucous membrane, and are sepa- 
rated from the thyroid cartilage by the lateral Crico-arytenoid and Thyro-aryte- 
noid muscles. This membrane 
and the muscles just men- 
tioned reduce greatly the inte- 
rior of the larynx. The crico- 
thyroid membrane with the 
membrana quadrangularis con- 
stitute the membrana elastica 
laryngis. 
The Crico-thyroid Articulation 
(articulatio cricothy reoidea) (Fig. 
968), on each side of the inferior 
cornu of the thyroid, with the 
cricoid cartilage on each side. 
A loose synovial membrane (cap- 
sula articularis cricothyr eoidea) 
encloses the articulation. 
The synovial capsule is 
strengthened by the ligamenta 
ceratocricoidea,which pass from 
the lesser cornu of the thyroid 
to the lamina of the cricoid 
cartilage. 
The Crico-arytenoid Articula- 
tion (articulatio cricoarytae- 
noidea) (Fig. 969) on each side is between the articular surface of the arytenoid 
cartilage and the arytenoid articular surface of the cricoid cartilage. 
The ligaments connecting the arytenoid cartilages to the cricoid are on each 
side a capsular ligament (capsula articularis cricoarytaenoidea) and a posterior 
crico-arytenoid ligament (tigamentum cricoarytaenoideum posterius). The capsular 
ligaments are thin and loose capsules attached to the margin of the articular 
ARYTENO- 
EPIGLOTTI DEUS 
LARYNGEAL 
'saccule 
IN FERIOR 
VOCAL CORD 
CRICO-_ 
THYREOIDEUS 
Fig. 970.-Coronal section of larynx, rear view of front half. 
(Testut.) 1368 
THE ORGANS OF VOICE AND RESPIRATION 
surfaces; they are lined internally by synovial membrane. The posterior crico- 
arytenoid ligaments extend from the cricoid to the inner and back part of the base 
of the arytenoid cartilage. 
The Crico-tracheal Ligament {ligamentum cricotracheale) connects the cricoid 
cartilage with the first ring of the trachea. It resembles the fibrous membrane 
which connects the cartilaginous rings of the trachea to each side. 
There is on each side an articulation between the arytenoid cartilage and the 
cartilage of Santorini {synchondrosis arycorniculald). The cartilage of Santorini is 
somewhat movable and is fixed to the arytenoid by lax connective tissue. From 
each cartilage of Santorini a band of connective tissue runs down to the lamina 
of the cricoid cartilage and to the pharyngeal mucous membrane. Beneath the 
arytenoid muscles the ligaments from the two sides join and pass down together. 
Thus is formed a Y-shaped ligament called the ligamentum comiculopharyngeum. 
The portion between the cricoid cartilage and the mucous membrane of the 
pharynx is sometimes called the ligamentum cricopharyngeum. 
Interior of the Larynx (Figs. 970, 971, and 972).-The cavity of the larynx 
{cavum laryngis) extends from the superior aperture of the larynx to the lower 
border of the cricoid cartilage. It is divided into two parts by the projection 
inward of the true vocal cords, between which is a narrow triangular fissure or 
chink, the rima glottidis. It is further subdivided by the false vocal cords. So 
we consider the larynx as divided into a portion above the false cords, a por- 
tion between the false and true vocal cords, and a portion below the true cords. 
The entrance of the first compartment is the superior aperture of the larynx. 
The Superior Aperture of the Larynx {culitus laryngis).-The superior aperture 
of the larynx (Figs. 970 and 971) is a triangular or cordiform opening, wide in front, 
narrow behind, and sloping obliquely downward and backward. It is bounded, 
in front, by the epiglottis; behind, by the apices of the arytenoid cartilages and 
the cornicula laryngis; and laterally, by a fold of mucous membrane, enclosing 
ligamentous and muscular fibres, stretched between the sides of the epiglottis 
and the apices of the arytenoid cartilages; these are the aryteno-epiglottidean 
folds (Figs. 971 and 972), on the margins of which the cuneiform cartilages form 
more or less distinct whitish prominences. 
The small gap between the cartilages of Santorini is called the incisura inter - 
arytaenoidea. On the pharynx, on either side of the posterior portion of the superior 
aperture of the larynx, is a recess, called the sinus pyriformis. 
Upper Compartment or Vestibule of the Laryngeal Cavity {vestibulum laryngis) (Figs. 
970 and 972).-The vestibule is the portion between the superior opening and the 
false vocal cords. It is much narrower below than above. It is bounded anteriorly 
by the mucous membrane-covered epiglottis. The lower part of the epiglottis 
exhibits a prominence called the cushion or tubercle {tuberculum epiglotticum) (Fig. 
970). The lateral wall of the vestibule on each side is the aryteno-epiglottidean fold 
{plica aryepiglottica) (Fig. 972), which extends from the summit of the arytenoid 
cartilage forward, upward, and outward to the margin of the epiglottis, and which 
contains fibres of the Thyro-epiglottideus and Arytenoideus muscles {musculus 
arytaenoepiglottidean). Near the posterior end of the fold are two trivial elevations: 
the anterior elevation is caused by the prominence of the cuneiform cartilage, and 
is called the cuneiform tubercle of Wrisberg {tuberculum cuneijorme [Wrisbergi]); the 
posterior elevation is caused by the anterior margin of the arytenoid cartilage and 
the cartilage of Santorini, and is called the comical tubercle of Santorini {tuberculum 
corniculatum [Santorini]). Between these elevations is a groove, the filtrum ven- 
triculi of Merkel, which passes into the space between the false and true vocal cords. 
The anterior elevation passes into the false vocal cord, the posterior elevation 
into the true vocal cord. The posterior portion of the laryngeal vestibule is the 
narrow space between the upper portions of the arytenoid cartilages. THE LARYNX 
1369 
The Middle Compartment of the Larynx (Figs. 970 and 972).-This lies between the 
false vocal cords above and the true vocal cords below. It is the smallest of the laryn- 
geal compartments. It opens into the vestibule by the way of the gap between the 
false vocal cords, which is called the false glottis; it opens into the lower compart- 
ment of the larynx by way of the space between the true vocal cords, the true glottis. 
The True Glottis.-The true glottis is the apparatus for producing tone and is 
formed by the true vocal cords. 
The Chink of the Glottis (rima glottidis) (Figs. 970 and 971).-The chink of the 
glottis is the elongated fissure or chink between the inferior or true vocal cords in 
front, and between the bases and vocal processes of the arytenoid cartilages behind. 
It is therefore frequently subdivided into an anterior, interligamentous or vocal por- 
tion, the glottis vocalis (pars intermembranacea), and a posterior, intercartilaginous 
or respiratory portion, the glottis respiratoria (pars intercartilaginea). Posteriorly it is 
limited by the mucous membrane passing between the arytenoid cartilages. The 
vocal portion averages about three-fifths of the length of the entire aperture. It 
is the narrowest part of the cavity of the larynx, and its level corresponds to the 
APEX OF SUP. HORN OF 
THYROID CARTILAGE 
CORNICULUM 
LARYNGIS 
INFERIOR 
VOCAL CORD 
CUNEIFORM 
CARTILAGE 
ARYTENO-EPIGLOT- 
TIDIAN FOLD 
APEX OF GREAT 
HORN OF HYOID 
SUPERIOR 
VOCAL CORD 
LATERAL GLOSSO- 
EPIGLOTTI DI AN FOLD 
MIDDLE GLOSSO- 
EPIG LOTTI DI A N FOLD 
Fig. 971.-Larynx, viewed from above. (Testut.) 
bases of the arytenoid cartilages. Its length, in the male, measures rather less 
than an inch (20 to 25 mm.); in the female it is shorter by 5 or 6 mm., or three 
lines. The width and shape of the rima glottidis vary with the movements of the 
vocal cords and arytenoid cartilages during respiration and phonation. In the 
condition of rest-i. e., when these structures are uninfluenced by muscular action, 
as in quiet respiration, the glottis vocalis is triangular, with its apex in front and 
its base behind, the latter being represented by a line about 8 mm. long, connect- 
ing the anterior extremities of the vocal processes, while the inner surfaces of the 
arytenoids are parallel to each other, and hence the glottis respiratoria is rectan- 
gular. During extreme adduction of the cords, as in the emission of a high note, 
the glottis vocalis is reduced to a linear slit by the apposition of the cords, while 
the glottis respiratoria is triangular, its apex corresponding to the anterior extrem- 
ities of the vocal processes of the arytenoids, which are approximated by the 
inward rotation of the cartilages. Conversely in extreme abduction of the cords, 
as in forced inspiration, the arytenoids and their vocal processes are rotated out- 
ward, and the glottis respiratoria is triangular in shape, but with its apex directed 
backward. In this condition the entire glottis is somewhat lozenge-shaped, the 
sides of the glottis vocalis diverging from before backward, those of the glottis THE ORGANS OF VOICE AND RESPIRATION 
1370 
respiratoria diverging from behind forward, the widest part of the aperture corre- 
sponding with the attachment of the cords to the vocal processes.1 
The Superior or False Vocal Cords(p/fcae ventriculares) (Figs. 970,971, and 972), so 
called because they are not directly concerned in the production of the voice. Each 
is a thick fold of mucous membrane, enclosing a narrow band of fibrous tissue, the 
superior thyro-arytenoid ligament (ligamentum ventriculare), which is attached in 
front to the angle of the thyroid cartilage immediately below the attachment of the 
epiglottis, and behind to the anterior surface of the arytenoid cartilage. The lower 
border of this ligament, enclosed in mucous membrane, forms a free crescentic 
margin, which constitutes the upper boundary of the ventricle of the larynx. 'The 
false vocal cord contains the lower part of the membrana quadrangularis with 
the ligamentum ventriculare, the muscle ventricularis and laryngeal glands. 
The Inferior or True Vocal Cords (plicae vacates) (Figs. 970, 971, 972, and 976), so 
called from their being concerned in the production of sound. Each is a strong 
EPIGLOTTIC 
^CARTILAGE 
HYOID- 
ARYTENO-EPI- 
GLOTTIDIAN FOLD 
'Thyro-hyoideus- 
THYRO-EPIGLOT-. 
TIC LIGAMENT 
THYROID 
CARTILAGE 
CRICOID 
CARTILAGE 
CRICOID 
CARTILAGE 
Fig. 972.-Sagittal section of larynx, right half. (Testut.) 
band, the inferior thyro-arytenoid ligament (ligamentum vacate), covered on its sur- 
face by a thin layer of mucous membrane. Each ligament consists of a band of 
yellow elastic tissue, attached in front to the depression between the alae of the 
thyroid cartilage, and behind to the anterior angle of the base of the arytenoid. 
This angle is called the vocal process. Its lower border is continuous with the 
thin lateral part of the crico-thyroid membrane. Its upper border forms the lower 
boundary of the ventricle of the larynx. Externally, the Thyro-arytenoideus 
muscle lies parallel with it. It is covered internally by mucous membrane, which is 
extremely pale, thin, and closely adherent to its surface. The upper margin of 
the true vocal cord is covered with mucous membrane, and is the lower boundary 
of the ventricle of the larynx. Over the vocal process it is yellowish (macula 
flava). The true vocal cord contains the upper part of the crico-thyroid mem- 
brane with the ligamentum vocale and the muscle vocalis. 
1 On the shape of the rima glottidis, in the various conditions of breathing and speaking, see Czermak, On the 
Laryngoscope, translated for the New Sydenham Society.-Ed. of 15th English edition. THH LARYNX 
1371 
The Ventricle of the Larynx or Laryngeal Sinus (ventriculus laryngis [Morgagnii]) 
(Figs. 970 and 972) is an oblong fossa, situated between the superior and inferior 
vocal cords on each side, and extending nearly their entire length. This fossa is 
bounded, above, by the free crescentic edge of the superior vocal cord; below, by 
the straight margin of the inferior vocal cord; externally, by the mucous mem- 
brane covering the corresponding Thyro-arytenoideus muscle. The anterior part 
of the ventricle leads up by a narrow opening into a caecal pouch of mucous 
membrane of variable size, called the laryngeal pouch. 
The Laryngeal Saccule or Pouch (appendix ventriculi) (Fig. 970), or laryngeal 
pouch, is a membranous sac, placed between the superior vocal cord and the inner 
surface of the thyroid cartilage, occasionally extending as far as its upper border 
or even higher; it is conical in form, and curved slightly backward. On the surface 
of its mucous membrane are the openings of sixty or seventy mucous glands, which 
are lodged in the submucous areolar tissue. This sac is enclosed in a fibrous cap- 
sule, continuous below with, the superior thyro-arytenoid ligament; its laryngeal 
surface is covered by the Aryteno-epiglottideus inferior muscle (compressor sacculi 
laryngis of Hilton); while its exterior is covered by the Thyro-arytenoideus and 
Thyro-epiglottideus muscles. These muscles compress the sacculus laryngis, and 
discharge the secretion it contains upon the vocal cords, the surfaces of which it is 
intended to lubricate. 
STERNO- 
THYREOIDEUS 
Fig. 973.-Muscles of larynx, front view. The sterno- 
thyroids and right thyro-hyoid have been removed. 
(Testut.) 
Fig. 974.-Muscles of larynx, from behind. 
(Testut.) 
The Lower Compartment of the Larynx (Figs. 970 and 972).-This space is just 
beneath the true vocal cords and leads into the trachea. It is called the additus glot- 
tidis inferior. Above, on cross-section, it is oval; below, it is round. It is bounded 
by the inner surface of the crico-thyroid membrane and the cricoid cartilage. 
Muscles of the Larynx (musculi laryngis).-We do not consider all muscles 
which are attached to laryngeal cartilages as laryngeal muscles. Some muscles 
so attached in reality belong to other regions, for instance, the Inferior constric- 
tor, the Stylo-pharyngeus, the Sterno-thyroid, the Thyro-hyoid, and the Palato- 
pharyngeus. The muscles which really belong to the larynx are called intrinsic. 
Four muscles of the vocal cords and rima glottidis are paired and one is single. 1372 
THE ORGANS OE VOICE AND RESPIRATION 
The paired muscles are the crico-thyroid, the posterior crico-arytenoid, the 
lateral crico-arytenoid, and the thyro-arytenoid. The single muscle is the aryte- 
noideus. 
A Crico-thyroid (m. cricothyreoideus} (Figs. 968, 970, and 973) is placed on each 
side. It is triangular in form, and situated at the forepart and side of the cricoid 
cartilage. It arises from the front and lateral part of the cricoid cartilage; its 
fibres diverge, passing obliquely upward and outward to be inserted into the lower 
border of the thyroid cartilage and into the anterior border of the lower cornu. 
The inner borders of these two muscles are separated in the middle line by a 
triangular interval occupied by the central part of the crico-thyroid membrane. 
The Posterior Crico-arytenoid (m. cricoarytaenoideus posterior} (Figs. 974, 975, and 
976), a paired muscle, arises from the 
broad depression occupying each lat- 
eral half of the posterior surface of the 
cricoid cartilage; its fibres pass up- 
ward and outward, converging to be 
inserted into the outer angle (muscu- 
Cornicula 
laryngis. 
Articular facet for 
inferior cornu of' 
thyroid cartilage. 
Fig. 975.-Muscles of larynx. Side view. Right ala 
of thyroid cartilage removed. 
Fig. 976.-Interior of the larynx, seen from above. 
(Enlarged.) 
lar process) of the base of the arytenoid cartilage. The upper fibres are nearly 
horizontal, the middle oblique, and the lower almost vertical.1 
The Arytenoideus (Figs. 972, 974, 975, and 976) is a single muscle filling up the 
posterior concave surface of the arytenoid cartilages. It arises from the posterior 
surface and outer border of one arytenoid cartilage, and is inserted into the corre- 
sponding parts of the opposite cartilage. It consists of three planes of fibres, two 
oblique and one transverse. The oblique fibres (m. arytaenoideus obliquus), the 
most superficial, form two fasciculi, which pass from the base of one cartilage to 
the apex of the opposite one. The transverse fibres (w. arytaenoideus transversus), 
the deepest and most numerous, pass transversely across between the two cartil- 
ages; hence the Arytenoideus was formerly considered as three muscles, the trans- 
1 Merkel, of Leipzig, has described a muscular slip which occasionally extends between the outer border of the 
posterior surface of the cricoid cartilage and the posterior margin of the inferior cornu of the thyroid ; this he 
calls the " Musculus kerato-cricoideus. It is not found in every larynx, and when present exists usually only 
on one side, but is occasionally found on both sides. Sir William Turner (Edinburgh Medical Journal, February, 
1860) states that it is found in about one case in five. Its action is to fix the lower horn of the thyroid cartilage 
backward and downward, opposing in some measure the part of the Crico-thyroid muscle, which is connected to 
the anterior margin of the horn.-Ed. of 15th English edition. THE LARYNX 
1373 
verse and the two oblique. A few of the oblique fibres are around the outer margin 
of the cartilage, and blend with the Thyro-arytenoid in the aryteno-epiglottidean 
fold, and are called the Aryteno-epiglottideus muscles. 
In order to expose the rest of the muscles of the larynx the thyroid cartilage 
of one side must be removed. Begin by taking away the crico-thyroid muscle, 
then dividing the lateral thyro-hyoid ligament; disarticulate the inferior cornu of 
the thyroid cartilage from the cricoid cartilage, then carefully cut through the 
thyroid cartilage a short distance from its union with its twin. The following 
muscles will then be exposed after a little cleaning: the Lateral crico-thyroid, 
the Thyro-arytenoid, the Thyro-epiglottideus. 
The Lateral Crico-arytenoid (m. cricoarytenoideus lateralis} (Figs. 975 and 976), 
a paired muscle, is smaller than the preceding, and of an oblong form. It arises 
from the upper border of the side of the cricoid cartilage, and, passing obliquely 
upward and backward, is inserted into the muscular process of the arytenoid 
cartilage in front of the posterior Crico-arytenoid muscle. 
The Thyro-arytenoid (m.thyroarytaenoideus}(¥\gs. 975 and 976), a paired muscle, 
is broad and flat. It lies parallel with the outer side of the true vocal cord. It 
arises in front from the lower half of the receding angle of the thyroid cartilage, 
and from the crico-thyroid membrane. Its fibres pass backward and outward, to 
be inserted into the base and anterior surface of the arytenoid cartilage. This 
muscle consists of two fasciculi.1 The inner or inferior fasciculus (m. vocalis}, the 
thicker, is prismatic in shape and is inserted into the vocal process of the aryte- 
noid cartilage, and into the adjacent portion of its anterior surface; it lies parallel 
with the true vocal cord, to which it is adherent. This fasciculus on its deeper 
surface gives off some fibres which are attached to the true vocal cord. These 
are called the ary-vocalis (Ludwig). The outer or superior fasciculus, the thinner, 
is inserted into the anterior surface and outer border of the arytenoid cartilage 
above the preceding fibres; it lies on the outer side of the sacculus laryngis, imme- 
diately beneath the mucous membrane.2 
The muscles of the epiglottis are the- 
Thyro-epiglottideus. Aryteno-epiglottideus superior. 
Aryteno-epiglottideus inferior. 
The Thyro-epiglottideus (m. thyroepiglottic^ is a delicate fasciculus, which 
arises from the inner surface of the thyroid cartilage, just external to the origin of 
the Thyro-arytenoid muscle, of which it is sometimes described as a part, and 
spreads over the outer surface of the sacculus laryngis; some of its fibres are lost 
in the aryteno-epiglottidean fold, while the others are continued forward to the 
margin of the epiglottis. 
The Aryteno-epiglottideus (Figs. 970 and 975) is properly divided into two 
muscles, a superior and an inferior. 
The Aryteno-epiglottideus superior consists of a few delicate muscular fasciculi, 
which arise from the apex of the arytenoid cartilages, and become lost in the 
fold of mucous membrane, the aryteno-epiglottidean fold, extending between the 
arytenoid cartilage and the side of the epiglottis. 
The Aryteno-epiglottideus inferior, the Compressor sacculi laryngis of Hilton, arises 
from the arytenoid cartilage, just above the attachment of the superior vocal cord; 
passing forward and upward,it spreads out upon the anterior surface of the epiglot- 
tis. This muscle is separated from the preceding by an indistinct areolar interval.3 
1 Henle describes these two portions as separate muscles, under the names of the External and Internal thyro- 
arytenoid.-Ed. of 15th English edition. 
2 Luschka has described a small but fairly constant muscle as the Arytenoideus rectus. It is attached below 
to the posterior concave surface of the arytenoid cartilage, beneath the Arytenoideus muscle, and, passing 
upward, emerges at the upper border of this muscle, and is inserted into the posterior surface of the cartilage of 
Santorini (Anatomy, by Hyrtl, p. 718).-Ed: of 15th English edition. 
3 Musculus triticeo-glossus. Bochdalek, Jr. (Prager Vierteljahrsschrift, 1866, 2d part) describes a muscle 
hitherto entirely overlooked, except by Henle, who makes a brief statement in his Anatomy, which arises from 
the nodule of cartilage (corpus triticeum) in the posterior thyro-hyoid ligament, and passes forward and upward 
to enter the tongue along with.the Hyo-glossus muscle. He met with this muscle eight times in twenty-two sub- 
jects. It occurred in both sexes, sometimes on both sides, at others on one only.-Ed. of 15th English edition. THE ORGANS OF VOICE AND RESPIRATION 
1374 
Actions.-In considering the action of the muscles of the larynx, they may 
be conveniently divided into two groups, viz.: 1. Those which open and close 
the glottis. 2. Those which regulate the degree of tension of the vocal cords. 
1. The muscles which open the glottis are the two Posterior crico-arytenoids; 
and those which close it are the Arytenoideus and the two Lateral crico-arytenoids. 
2. The muscles which regulate the tension of the vocal cords are the two Crico- 
thyroids, which tense and elongate them, and the two Thyro-arytenoids, which 
relax and shorten them. The Thyro-epiglottideus is a depressor of the epiglottis, 
and the Aryteno-epiglottideus, superior and inferior, constrict the superior aper- 
ture of the larynx. 
The Posterior crico-arytenoids separate the chordae vocales, and consequently open the glottis, 
by rotating the arytenoid cartilages outward around a vertical axis passing through the crico- 
arytenoid joints, so that their vocal processes and the vocal cords attached to them become widely 
separated. 
The Lateral crico-arytenoids close the glottis by rotating the arytenoid cartilages inward so 
as to approximate their vocal processes. 
The Arytenoideus muscle approximates the arytenoid cartilages, and thus closes the opening 
of the glottis, especially at its back part. 
The Crico-thyroid muscles produce tension and elongation of the vocal cords. This is effected 
as follows: the thyroid cartilage is fixed by its extrinsic muscles; then the Crico-thyroid muscles, 
when they act, draw upward the front of the cricoid cartilage, and so depress the posterior por- 
tion, which carries with it the arytenoid cartilages, and thus elongate the vocal cords. 
The Thyro-arytenoid muscles, consisting of two parts having different attachments and 
different directions, are rather complicated as regards their action. Their main use is to draw 
the arytenoid cartilages forward toward the thyroid, and thus shorten and relax the vocal cords. 
But, owing to the connection of the inner portion with the vocal cord, this part, if acting sepa- 
rately, is supposed to modify its elasticity and tension, and the outer portion, being inserted 
into the outer part of the anterior surface of the arytenoid cartilage, may rotate it inward, and 
thus narrow the rima glottidis by bringing the two cords together. 
The Thyro-epiglottidei may depress the epiglottis; they assist in compressing the sacculi 
laryngis. The Aryteno-epiglottideus superior constricts the superior aperture of the larynx, 
when it is drawn upward, during deglutition. The aryteno-epiglottideus inferior, together with 
some fibres of the Thyro-arytenoidei, compress the sacculus laryngis. 
The Mucous Membrane of the Larynx is continuous above with that lining the 
mouth and pharynx, and it is prolonged through the trachea and bronchi into the 
lungs. It lines the posterior surface and the anterior part of the upper surface of 
the epiglottis, to which it is closely adherent. In the rest of the larynx, above the 
true vocal cords, it is lax and rests upon a considerable submucous layer. The 
mucous membrane, with the submucous coat, ligamentous and muscular fibres, 
forms the aryteno-epiglottidean folds, which folds are the lateral boundaries of the 
superior aperture of the larynx. It lines the whole of the cavity of the larynx; 
forms by its reduplication the chief part of the superior or false vocal cord; and, 
from the ventricle, is continued into the sacculus laryngis. It is then reflected 
over the true vocal cords, where it is thin and very intimately adherent; covers 
the inner surface of the crico-thyroid membrane and cricoid cartilage; and is 
ultimately continuous with the lining membrane of the trachea. The forepart of 
the anterior surface and the upper half of the posterior surface of the epiglottis, 
the upper part of the aryteno-epiglottidean folds, and the true vocal cords are 
covered by stratified squamous epithelium; the rest of the laryngeal mucous 
membrane is covered by columnar ciliated cells. 
The mucous membrane above the rima glottidis is extremely sensitive, and 
during life the lightest touch of a foreign body produces cough. 
Glands.-The mucous membrane of the larynx is furnished with numerous 
muciparous glands, the orifices of which are found in nearly every part; they 
are very numerous upon the epiglottis, being lodged in little pits in its substance; 
they are also found in large numbers along the posterior margin of the aryteno- 
epiglottidean fold, in front of the arytenoid cartilages, where they are termed the THE LARYNX 
1375 
arytenoid glands. They exist also in large numbers upon the inner surface of the 
sacculus laryngis. None are found on the surface of the true vocal cords. 
Vessels and Nerves.-The arteries of the larynx (Fig. 977) are the laryngeal 
branches derived from the superior and inferior thyroid. The superior laryngeal artery 
from the superior thyroid courses along by the internal laryngeal nerve; the inferior 
laryngeal artery from the inferior thyroid courses along with the recurrent laryngeal 
nerve. The veins accompany the arteries; those accompanying the superior laryn- 
geal artery join the superior thyroid vein which opens into the internal jugular 
vein; while those accompanying the inferior laryngeal artery join the inferior 
thyroid vein which opens into the innominate vein. The laryngeal lymphatics arise 
from a network in the mucous membrane. This network is divisible into two 
portions, a superior and an inferior, which are to be regarded as almost inde- 
pendent areas. The superior region includes all of the "laryngeal mucous 
membrane above the glottis, epiglottis, aryteno-epiglottidean folds, interarytenoid 
region, and superior vocal cords."1 The inferior area is the laryngeal mucous 
Superior 
thyroid 
artery. 
Superior 
■laryngeal 
artery. 
Fig. 977.-The origin and distribution of the arteries of the larynx. (Luschka.) 
membrane below the glottis. The lymphatics of one-half of the larynx do not 
communicate with those of the other half in the median line in front, but do 
in the median line behind. The efferent vessels from the superior network 
accompany the superior laryngeal artery, pierce the thyro-hyoid membrane, 
and divide into three sets. One or two lymphatic vessels pass upward and 
terminate in a gland slightly below the posterior belly of the Digastric muscle. 
A group of vessels passes horizontally outward to terminate in the glands 
situated on the internal jugular vein on a level with the bifurcation of the 
common carotid artery. Another group descends and empties into the internal 
jugular group of glands at a lower level than the horizontal vessels. Trunks from 
the inferior network of the laryngeal mucous membrane form two groups. The 
anterior or supracricoid group consists of three trunks which pass through the crico- 
thyroid membrane, to empty into the pre-laryngeal glands, the pre-tracheal gland, 
and the middle and lower deep cervical glands.2 The posterior group consists 
1 Philip R. W. De Santi in the Lancet, June 18, 1904. 2 Poirier, Cun^o, Most, De Santi. 1376 
THE ORGANS OF VOICE AND RESPIRATION 
of "from three to five trunks, which pass over the crico-tracheal fascia at the 
junction of the lateral and posterior aspects of the trachea,"1 and terminate in 
the recurrent glands about the recurrent laryngeal nerve. The nerves are derived 
from the internal and external laryngeal branches of the superior laryngeal nerve, 
from the inferior or recurrent laryngeal, and from the sympathetic. The internal 
laryngeal nerve is almost entirely sensory, but some motor filaments are said to be 
carried by it to the Arytenoideus muscle. It divides into a branch which is dis- 
tributed to both surfaces of the epiglottis, a second to the aryteno-epiglottidean 
folds, and a third, the largest, which supplies the mucous membrane over the 
back of the larynx and communicates with the recurrent laryngeal. The external 
laryngeal nerve supplies the Crico-thyroid muscle. The recurrent laryngeal 
passes upward under the lower border of the Inferior constrictor, and enters the 
larynx between the cricoid and thyroid cartilages. It supplies all the muscles of 
the larynx except the Crico-thyroid and part of the Arytenoideus. The sensory 
branches of the laryngeal nerves form subepithelial plexuses, from which fibres 
ascend to end between the cells covering the mucous membrane. 
Over the posterior surface of the epiglottis, in the aryteno-epiglottidean folds, 
and less regularly in some other parts, taste-buds, similar to those in the tongue, 
are found. 
THE TRACHEA AND BRONCHI (Fig. 978) 
The trachea or windpipe is a cartilaginous membranous, elastic, cylindrical 
tube, flattened posteriorly, which extends from the lower part of the larynx, on a 
level with the sixth cervical vertebra, to opposite the body of the fourth, or some- 
times of the fifth, dorsal vertebra, where it divides (bifurcatio tracheae) into two 
bronchi, one for each lung. This point is at the level of the spine of the fourth 
dorsal vertebra. The trachea is found to be more deeply placed the lower down 
it is examined. It is in the median line, deviating below a very little to the right 
side. When a cross-section is made of the trachea it is seen that its anterior and 
lateral walls are rounded, but its posterior wall is flat (Fig. 982). The largest 
diameter of the tube is the middle; from this point the diameter diminishes toward 
the bronchi and toward the laryngeal end. The trachea measures about four 
inches and a half in length; its diameter from side to side is from three-quarters 
of an inch to an inch, being always greater in the male than in the female. 
Relations.-The anterior surface of the trachea is convex, and covered in the 
neck, from above downward, by the isthmus of the thyroid gland, the inferior 
thyroid veins, the arteria thyroidea ima (when that vessel exists), the Sterno-hyoid 
and Sterno-thyroid muscles, the cervical fascia, and more superficially, by the 
anastomosing branches between the anterior jugular veins: in the thorax it is 
covered from before backward by the first piece of the sternum, the remains of the 
thymus gland, the left innominate vein, the arch of the aorta, the innominate and 
left common carotid arteries, and the deep cardiac plexus. Posteriorly, it is in 
relation with the oesophagus; laterally, in the neck, it is in relation with the com- 
mon carotid arteries, the lateral lobes of the thyroid gland, the inferior thyroid 
arteries, and recurrent laryngeal nerves; and, in the thorax, it lies in the upper 
part of the interpleural space, that is, in the superior mediastinum, and is in relation 
on the right to the pleura and right vagus, and near the root of the neck to the 
innominate artery; on its left side are the recurrent laryngeal nerve, the aortic 
arch, the left common carotid and subclavian arteries. 
The Right Bronchus (bronchus dexter).-The unbranched portion of the right 
bronchus, wider, shorter, and more vertical in direction than the left, is about 
an inch in length, and enters the hilum of the right lung opposite the fifth dorsal 
1 De Santi, in the Lancet, June 18, 1904. THE TRACHEA AND BRONCHI 
1377 
vertebra. It forms an angle to the median plane of about 29 degrees. The vena 
azygos major arches over it from behind; and the right pulmonary artery lies below 
and then in front of it. About three-quarters of an inch from its commencement 
it gives off a branch to the upper lobe of the right lung. This is termed the 
eparterial branch (ramus branchialis eparterialis), because it is given off above 
the right pulmonary artery. The bronchus now passes below the artery, and is 
Superior 
Cornu. 
Inferior 
Cornu. ' 
Fig. 978.-Front view of cartilages of larynx; the trachea and bronchi (the right bronchus is not shown as 
steep as it really is. 
known as the hyparterial branch (ramus branchialis hyparterialis). It divides 
into two branches for the middle and lower lobs. 
If a transverse section of the trachea is made a short distance above its point 
of bifurcation, and a bird's-eye view taken of its interior (Fig. 982), the septum 
placed at the bottom of the trachea and separating the two bronchi will be seen 
to occupy the left of the median line, and the right bronchus appears to be a 
more direct continuation than the left, so that any solid body dropping into the 
trachea would naturally be directed toward the right bronchus. This tendency is 
aided by the larger size of the right tube as compared with its fellow. This fact 1378 
THE ORGANS OF VOICE AND RESPIRATION 
serves to explain why a foreign body in the trachea more frequently falls into the 
right bronchus than into the left.1 
The Left Bronchus (bronchus sinister).-The left bronchus is smaller and 
longer than the right, being nearly two inches in length. It forms an angle to the 
median plane of about 46 degrees. It is slightly 
curved and enters the root of the left lung, oppo- 
site the sixth dorsal vertebra, about an inch 
lower than the right bronchus. It passes be- 
neath the arch of the aorta, crosses in front of 
the oesophagus, the thoracic duct, and the de- 
scending aorta, and has the left pulmonary artery 
lying at first above, and then in front of it. The 
left bronchus has no branch corresponding to 
the eparterial branch of the right bronchus, and 
therefore it has been supposed by some that 
there is no upper lobe to the left lung, but that 
the so-called upper lobe corresponds to the 
middle lobe of the right lung. The left bron- 
chus does have an hyparterial branch. 
When the main or stem bronchus enters the 
lung on each side it appears to divide into nearly 
equal branches at the root of the lung, but a 
somewhat similar arrangement to what is found 
in many animals may be made out where each 
main bronchus passes downward and backward 
toward the extremity of the lower lobe, and ends 
near the posterior surface of the base of the lung, 
a portion of pulmonary substance which is be- 
tween the Diaphragm and the wall of the chest. 
It gives off four branches, or lateral bronchi 
(rami bronchioles), at intervals in two directions, dorsally and ventrally, and, in 
addition, accessory branches, which arise from the front of the bronchus and 
pass mesially and dorsally into the inferior lobe. In the right bronchus the 
first ventral branch supplies the middle lobe, the other three and all the dorsal 
going to the lower lobe; in the left bronchus, the first ventral branch sup- 
plies the middle lobe, the other three and all the dorsal going to the lower 
lobe; in the left bronchus, the first central supplies the superior lobe, and all the 
others, both ventral and dorsal, go to the lower lobe. The dorsal and ventral 
branches divide into smaller branches, and these again into smaller branches or 
bronchioles (Fig. 981). Each bronchiolus divides into minute branches (bronchioli 
respiratorii) (Fig. 981), the walls of which show numerous areas of bulging called 
alveoli (Fig. 981). From the bronchioli respiratorii come the terminal branches 
of the bronchi. These terminal branches are the alveolar ducts (ductuli alveolares), 
and they are bulged by numerous alveoli (Fig. 981). They connect by openings 
at their termination with several cavities of irregular form, which are called atria. 
Each atrium is connected with several or many larger cavities, known as sacculi 
alveolares, air-cells, or air-sacs (infundibula). The entire surface of the air-sacs is 
filled with small cavities, the pulmonary alveoli (alveoli pulmonis). An alveolar 
duct with its branches forms a pulmonary lobule (lobidus pulmonis) (Fig. 980). 
Structure of the Trachea.-The trachea is composed of imperfect cartilagin- 
ous rings, fibrous membrane, muscular fibres, mucous membrane, and glands. 
The Cartilages.-The cartilages vary from sixteen to twenty in number; each 
forms an imperfect ring, which surrounds about two-thirds of the cylinder of the 
Fig. 979.-Internal surface of the bronchi. 
(Poirier and Charpy.) 
1 Reigel asserts that the entrance of a foreign body into the left bronchus is bv no means so infrequent as is 
generally supposed. See also Med.-Chir. Transactions, vol. Ixxi. p. 121.-Ed. of 15th English edition. THE TRACHEA AND BRONCHI 
1379 
trachea, being imperfect behind, where the tube is completed by fibrous mem- 
brane. The cartilages are placed horizontally above each other, separated by 
narrow membranous intervals. They measure about two lines in depth, and half 
a line in thickness. Their outer surfaces are flattened, but internally they are 
convex, from being thicker in the middle than at the margins. Two or more of 
the cartilages often unite, partially or completely, and are sometimes bifurcated 
at their extremities. They are highly elastic, but sometimes become calcified in 
advanced life. In the right bronchus the cartilages vary in number from six to 
eight; in the left, from nine to twelve. They 
are shorter and narrower than those of the 
trachea. The peculiar cartilages are the first 
and the last. 
The First Cartilage is broader than the rest, 
and sometimes divided at one end; it is con- 
nected by fibrous membrane with the lower 
INTERLOBULAR 
BRONCHUS 
ALVEOLI 
DUCT\ 
ALVEOLI 
BRONCHIOLE 
RESPIRATORY 
BRONCHIOLE 
ALVEOLI 
Fig. 980.-A pulmonary lobule. (Poirier and 
Charpy.) 
Fig. 981.-The terminal bronchial tubes. The respiratory- 
bronchiole and alveoli. (Poirier and Charpy.) 
border of the cricoid cartilage, with which or with the succeeding cartilage it is 
sometimes blended. 
The Last Cartilage is thick and broad in the middle, in consequence of its lower 
border being prolonged into a triangular hook-shaped process which curves down- 
ward and backward between the two bronchi. It terminates on each side in an 
imperfect ring which encloses the com- 
mencement of the bronchi. The cartil- 
age above the last is somewhat broader 
than the rest at its centre. 
The Fibrous Membrane.-The cartil- 
ages are enclosed in an elastic fibrous 
membrane which forms a double layer, 
one layer, the thicker of the two, passing 
over the outer surface of the ring, the 
other over the inner surface; at the 
upper and lower margins of the cartilages 
these two layers blend together to form a 
single membrane, which connects the rings one with another. They are thus, as 
it were, embedded in the membrane. In the space behind, between the extremi- 
ties of the rings, the membrane forms a single distinct layer. 
The Muscular Fibres.-The muscular fibres are disposed in two layers, longi- 
tudinal and transverse 
Left. 
Right. 
Fig. 982.-Transverse section of the trachea, just 
above its bifurcation, with a bird's-eye view of the 
interior. 1380 
THE ORGANS OF VOICE AND RESPIRATION 
The Longitudinal Fibres are the most external, and consist merely of a few scat- 
tered longitudinal bundles of fibres. 
The Transverse Fibres constitute the Trachealis muscle of Todd and Bowman. The 
most internal form a thin layer which extends transversely between the ends of 
the cartilages and the intervals between them at the posterior part of the trachea. 
The muscular fibres are of the unstriped variety. 
The Mucous Membrane.-The mucous membrane is continuous above with that 
of the larynx, and below with that of the bronchi. Microscopically, it consists of 
areolar and lymphoid tissue, and presents a well-marked basement-membrane, 
supporting a layer of columnar, ciliated epithelium, between the deeper ends of 
which are smaller triangular cells, the bases of which, often branched, are attached 
to the basement-membrane. These triangular cells are mucus-secreting, and may 
be seen as goblet-cells or chalice-cells when their contents have been discharged. 
In the deepest part of the mucous membrane, and especially between the mucous 
and submucous layers, longitudinally arranged fibres are very abundant and form 
a distinct layer. 
The Tracheal Glands (glandulae tracheales).-The tracheal glands are found in 
great abundance at the posterior part of the trachea. They are racemose glands, 
and consist of a basement-membrane lined by columnar mucus-secreting cells. 
They are situated at the back of the trachea, outside the layer of muscular tissue, 
between it and the outer fibrous layer. Their excretory ducts pierce the muscular 
and inner fibrous layers, and pass through the submucous and mucous layers to 
open on the surface of the mucous membrane. Some glands of smaller size are 
also found at the sides of the trachea, between the layers of fibrous tissue con- 
necting the rings, and others immediately beneath the mucous coat. The secre- 
tion from these glands serves to lubricate the inner surface of the trachea. 
Vessels and Nerves.-The trachea is supplied with blood by the inferior thy- 
roid arteries. The veins terminate in the thyroid venous plexus. The nerves 
are derived from the pneumogastric and its recurrent branches and from the 
sympathetic. 
Lymphatic Glands.-The trachea is surrounded by lax connective tissue which 
contains numerous lymph glands, known as the peritracheo-bronchial glands. They 
are divided into four groups (Barety). A group to the right side, in the angle 
between the trachea and right bronchus and ascending to the region of the sub- 
clavian vessels. A group to the left side, in the angle formed by the trachea and 
left bronchus, and ascending to about the arch of the aorta and the recurrent 
laryngeal nerve. The two groups just described are usually called tracheal glands 
(lymphoglandulae tracheales). A third group is in the angle formed by the bifur- 
cation of the trachea. These constitute the bronchial glands (lymphoglandulae 
bronchioles). They number ten or twelve (Cuneo). A fourth group, the inter- 
bronchial glands, are found in angles of bifurcation of the larger bronchi in the 
lung parenchyma. Very early in life the peritracheo-bronchial glands become 
dark or even black from the deposition of carbonaceous substance brought by 
the leukocytes from the bronchial tubes. This condition is called anthracosis. 
Surface Form.-In the middle line of the neck some of the cartilages of the larynx can readily 
be distinguished. In the receding angle below the chin the hyoid bone can easily be made 
out, and a finger's breadth below it is the pomum Adami, the prominence between the upper 
borders of the two alae of the thyroid cartilage. About an inch below this, in the middle line, is 
a depression corresponding to the crico-thyroid space, in which the operation of laryngotomy is 
performed. This depression is bounded below by a prominent arch, the anterior ring of the 
cricoid cartilage, below which the trachea can be felt, though it is only in the emaciated adult 
that the separate rings can be distinguished. The lower part of the trachea is not easily made 
out, for as it descends in the neck it takes a deeper position, and is farther removed from the 
surface. The level of the vocal cords corresponds to the middle of the anterior margin of the 
thyroid cartilage. THE TRACHEA AND BRONCHI 
1381 
With the laryngoscope, the following structures can be seen: The base of the tongue and 
the upper surface of the epiglottis, with the glosso-epiglottic ligaments; the superior aperture of 
the larynx, bounded on either side by the aryteno-epiglottidean folds, in which may be seen two 
rounded eminences corresponding to the cornicula and cuneiform cartilages. Beneath these, the 
true and false vocal cords, with the ventricle between them. Still deeper, the cricoid cartilage 
and some of the anterior parts of the rings of the trachea, and sometimes, in deep inspiration, the 
bifurcation of the trachea. 
Surgical Anatomy.-Foreign bodies often find their way into the air-passages. These may 
be either large soft substances, as a piece of meat, which may become lodged in the upper aper- 
ture of the larynx or in the rima glottidis, and cause speedy suffocation unless rapidly got rid of, 
or unless an opening is made into the air-passages below, so as to enable the patient to breathe. 
Smaller bodies, frequently of a hard nature, such as cherry- or plum-stones, small pieces of bone, 
buttons, etc., may find their way through the rima glottidis into the trachea or bronchus, or may 
become lodged in the ventricle of the larynx. The dangers then depend not so much upon the 
mechanical obstruction as upon the spasm of the glottis which they excite from reflex irritation. 
When lodged in the ventricle of the larynx, they may produce very few symptoms beyond sudden 
loss of voice or alteration in the voice sounds, immediately following the inhalation of the foreign 
body. When, however, they are situated in the trachea, they are constantly striking against 
the vocal cords during expiratory efforts, and produce attacks of dyspnoea from spasm of the 
glottis. When lodged in the bronchus, they usually become fixed there, and, occluding the 
lumen of the tube, cause a loss of the respiratory murmur on the affected side, which is, as stated 
above, more often the right. 
Beneath the mucous membrane of the upper part of the air-passages there is a considerable 
amount of submucous tissue which is liable to become much swollen from effusion in inflamma- 
tory affections, constituting the disease known as " oedema of the glottis." This effusion does 
not extend below the level of the true vocal cords, on account of the fact that the mucous mem- 
brane is closely adherent to these structures, without the intervention of any submucous tissue. 
So that, in cases of this disease in which it is necessary to open the air-passages to prevent suffo- 
cation, the operation of laryngotomy is sufficient. 
Chronic laryngitis is an inflammation of the mucous glands of the larynx, which occurs in 
those who speak much in public, and is known as " clergyman's sore throat." It is due to the 
dryness induced by the large amount of cold air drawn into the air-passages during prolonged 
speaking, which incites increased activity in the mucous glands to keep the parts moist, and 
this eventually terminates in inflammation of these structures. 
Ulceration of the larynx may occur from syphilis, either as a superficial ulceration, or from 
the softening of a gumma; from tuberculous disease (laryngeal phthisis), or from malignant 
disease (epithelioma). 
The air-passages may be opened surgically in two different situations: through the crico- 
thyroid membrane (laryngotomy'), or in some part of the trachea (tracheotomy); and to these 
some surgeons have added a third method, by opening the crico-thyroid membrane and 
dividing the cartilage with the upper ring of the trachea (laryngo-tracheotomy). 
Laryngotomy is anatomically the more simple operation: it can readily be performed, and 
should be employed in those cases where the air-passages require opening in an emergency for 
the relief of some sudden obstruction to respiration. The crico-thyroid membrane is very 
superficial, being covered only in the middle line by the skin, superficial fascia, and the deep 
fascia. On each side of the middle line it is also covered by the Sterno-hyoid and Sterno-thyroid 
muscles, which diverge from each other at their upper parts, leaving a slight interval between 
them. On these muscles rest the anterior jugular veins. The only vessel of any importance 
in connection with this operation is the crico-thyroid artery, which crosses the crico-thyroid 
membrane, and which may be wounded, but rarely gives rise to any trouble. The operation 
is performed thus: the head being thrown back and steadied by an assistant, the finger is passed 
over the front of the neck, and the crico-thyroid depression felt for. A vertical incision is then 
made through the skin, in the middle line over this spot, and carried down through the fascia 
until the crico-thyroid membrane is exposed. A cross-cut is then made through the membrane, 
close to the upper border of the cricoid cartilage, so as to avoid, if possible, the crico-thyroid 
artery, and a tracheotomy tube is introduced. It has been recommended, as a more rapid way 
of performing the operation, to make a transverse instead of a longitudinal cut, through both the 
superficial and deep structures, and thus to open at once the air-passages. It will be seen, however, 
that in opening in this way the anterior jugular veins would be in danger of being wmunded. 
Tracheotomy may be performed either above or below the isthmus of the thyroid body, or 
this structure may be divided and the trachea opened behind it. 
The isthmus of the thyroid gland usually crosses the second and third rings of the trachea; 
along its upper border is frequently to be found a large transverse communicating branch between 
the superior thyroid veins; and the isthmus itself is covered by a venous plexus formed between 
the thyroid veins of the opposite sides. Theoretically, therefore, it is advisable to avoid dividing 
this structure in opening the trachea. 1382 
THE ORGANS OF VOICE AND RESPIRATION 
Above the isthmus the trachea is comparatively superficial, being covered by the skin, super- 
ficial fascia, deep fascia, Sterno-hyoid and Sterno-thyroid muscles, and a second layer of the 
deep fascia, which, attached above to the lower border of the hyoid bone, descends beneath the 
muscles to the thyroid body, where it divides into two layers and enclose the isthmus. 
Below the isthmus the trachea lies much more deeply, and is covered by the Sterno-hyoid 
and the Sterno-thyroid muscles and a quantity of loose areolar tissue in which is a plexus of 
veins, some of them of large size; they converge to two trunks, the inferior thyroid veins, which 
descend on either side of the median line on the front of the trachea and open into the innomi- 
nate veins. In the infant the thymus gland ascends a variable distance along the front of the 
trachea, and opposite the episternal notch the windpipe is crossed by the left innominate vein. 
Occasionally, also, in young subjects, the innominate artery crosses the tube obliquely above 
the level of the sternum. The thyroidea ima artery, when that vessel exists, passes from below 
upward along the front of the trachea. 
From these observations it must be evident that the trachea can be more readily opened 
above than below the isthmus of the thyroid body. 
Tracheotomy above the isthmus is performed thus: the patient should, if possible, be laid 
on his back on a table in a good light. A pillow is to be placed under the shoulders and the 
head thrown back and steadied by an assistant. The surgeon standing on the right side of his 
patient makes an incision from an inch and a half to two inches in length in the median line of 
the neck from the top of the cricoid cartilage. The incision must be made exactly in the middle 
line, so as to avoid the anterior jugular veins, and after the superficial structures have been 
divided the interval between the Sterno-hyoid muscles must be found, the raphe divided, and 
the muscles drawn apart. The lower border of the cricoid cartilage must now be felt for, and 
the upper part of the trachea exposed from this point downward in the middle line. Bose has 
recommended that the layer of fascia in front of the trachea should be divided transversely at 
the level of the lower border of the cricoid cartilage, and, having been seized with a pair of 
forceps, pressed downward with the handle of the scalpel. By this means the isthmus of the 
thyroid gland is depressed, and is saved from all danger of being wounded, and the trachea is 
cleanly exposed. The trachea is now transfixed with a sharp hook and drawn forward in order 
to steady it, and is then opened by inserting the knife into it and dividing the two or three upper 
rings from below upward. If the trachea is to be opened below the isthmus, the incision to 
expose it must be made from a little below the cricoid cartilage to the top of the sternum. 
In the child the trachea is smaller, more deeply placed, and more movable than in the adult. 
In fat or short-necked people, or in those in whom the muscles of the neck are prominently 
developed, the trachea is more deeply placed than in others. 
A portion of the larynx or the whole of it has been removed for malignant disease, laryn- 
gectomy. 
Some surgeons do preliminary tracheotomy, insert a Trendelenburg cannula to prevent the 
flow of blood downward into the lungs, and then remove the larynx. Other surgeons do not 
employ preliminary tracheotomy. 
Perier's method of laryngectomy is as follows: Make a vertical incision in the median line 
from the level of the hyoid bone to below the level of the cricoid cartilage. Make a transverse 
incision at each end of the vertical incision. This makes an I-shaped wound. 
Separate the soft parts from the larynx and upper part of the trachea, and separate these two 
structures from the oesophagus. After arresting bleeding, divide the trachea below the cricoid 
cartilage, introduce a special cannula, complete the removal of the larynx, suture the opening of 
the trachea to the lower angle of the wound, and close the rest of the wound after securing drainage. 
In malignant disease of the larynx the associated lymphatic glands must be removed. 
Partial laryngectomy, according to Sir F. Semon, is the removal of not less than one wing of 
the thyroid cartilage. Removal of a lesser piece of the thyroid or of a bit of the arytenoid or 
cricoid he considers with the operation of thyrotomy. 
THE PLEURAE (Figs. 983, 984, 985, 986, 987). 
Each lung is invested, upon its external surface, by an exceedingly delicate 
serous membrane, the pleura, which encloses the organ as far as its root, and is 
then reflected upon the inner surface of the thorax. The portion of the serous 
membrane investing the surface of the lung and dipping into the fissures between 
its lobes is called the pulmonary pleura or the visceral layer of the pleura (pleura 
pulmonalis) (Fig. 983), while that which lines the inner surface of the chest is called 
the parietal layer of the pleura (pleura parietalis) (Fig. 983). The two layers join at 
the hilum of the lung. The space between these two layers is called the cavity of the THE PLEURAE 
1383 
pleura (cavum pleurae), and contains a very little clear fluid. It must be borne 
in mind that in the healthy condition the two layers are in contact, and there 
TRIANGULARIS STERNI. 
Interned Mammary Vessels.' 
Pleura Pulmonalis. 
Left Phrenic Nerve. 
Pleura Costal is. 
Mediastinum 
Sympathetic Nerve. 
Thoracic Duct 
Vena Azygos Major 
Pneumogastric Nerves 
Posterior. 
Fig. 983.-A transverse section of the thorax, showing the relative position of the viscera and the 
reflections of the pleurae. 
is no real cavity until the lung becomes collapsed and separates from the wall 
of the chest. Each pleura is therefore a shut sac, one occupying the right, the 
other the left half of the thorax, and they are perfectly separate from each other. 
SCALENUS 
MINIMUS 
SYMPATHETIC 
GANGLION 
Fig. 984.-The dome of the pleura. (Poirier and Charpy.) 
The two pleurae do not meet in the middle line of the chest, excepting anteriorly 
opposite the second and third pieces of the sternum-a space being left between THE ORGANS OF VOICE AND RESPIRATION 
1384 
them, which contains ail the viscera of the thorax excepting the lungs; this is the 
mediastinum. 
Reflections of the Pleurae (Fig. 983). The Pleura Pulmonalis (Fig. 983). -The 
pleura pulmonalis is closely attached to the surface of the lung and enters into the 
SIBSON'S 
APONEUROSIS 
COSTAPLEURAL 
LIGAMENT 
SCALENUS 
MINIMUS' 
MUSCLE 
TRACHEO- 
OESOPHAGEAL 
FASCIA 
Fig. 985.- The supports of the pleural dome. The oesophagus, trachea and arteries have been cut and pulled 
aside to show the pleural reinforcements. (Poirier and Charpy.) 
SIXTH 
RIB 
. LONGUS COLLI 
MUSCLE 
PLEURA 
SYMPATHETIC 
GANGLION 
PHRENICO- 
COSTAL SINUS 
FIRST 
THORACIC 
NERVE 
.SIBSON'S 
APONEUROSIS 
CELLULAR 
TISSUE 
DIAPHRAGM 
Fig. 986.-The supports of the pleural dome. (Poirier and 
Charpy.) 
Fig. 987.-Section of the wall of the 
thorax, showing the phrenico-costal sinus. 
(Poirier and Charpy.) 
depths of the interlobar fissures. It leaves the lung surface at the hilum, covers the 
root of the lung for a little way (Figs. 990 and 991), and then passes into the medi- THE PLEURAE 
1385 
astinal pleura. Between the hilum and the mediastinal pleura there is a thickened 
pleural fold, triangular in outline, and called the ligamentum pulmonale or the 
ligamentum latum pulmonis (Figs. 990 and 991). It is formed by the two layers of 
the pulmonary pleura coming in contact below the root of the lung. This fold 
passes from the lower part of the inner pulmonary surface to the pericardium, 
and the lower border is free or attached to the diaphragmatic pleura. In the 
right lung the origin of this ligament is in front of the groove for the azygos 
vein; in the left lung it is in front of the groove for the thoracic aorta. 
The Pleura Parietalis.-The pleura parietalis is a continuous membrane, but 
for convenience is divided into the cervical pleura, costal pleura, mediastinal pleura, 
and diaphragmatic pleura. 
The Cervical Pleura or Dome of the Pleura or Cupola (cupula pleurae) (Fig. 986) is 
the dome-shaped roof of the cavity of the pleura. It projects above the apex of the 
lung to the neck of the first rib. As the first rib is placed obliquely, the dome of the 
pleura reaches from one inch to two inches above the anterior extremity of the first 
rib, and from one-half an inch to one and one-half inches above the clavicle. On the 
outer side of the cervical pleura are the Scalenus anticus and medius muscles. Just 
below the apex, on the anterior and inner surface, is a groove for the subclavian 
artery, which vessel passes over it in an arch (Fig. 984). A little below the groove 
for the subclavian artery is a broader and shallower groove for the innominate and 
subclavian veins. Above the subclavian artery and in front and above the cervical 
pleura are the cords of origin of the brachial plexus and the inferior cervical gan- 
glion (Fig. 984). The dome is strengthened and kept in place by Sibson's aponeurosis 
or the vertebro-pleural ligament (Figs. 985 and 986). This comes from a little piece 
of muscle, the Scalenus minimus muscle, which originates from the transverse pro- 
cess of the seventh cervical vertebra, broadens and becomes aponeurotic as it de- 
scends, and is inserted into the inner margin of the first rib (Figs. 984 and 985). It 
is also strengthened by the costa-pleural ligament (Fig. 985), from the inner surface 
of the neck of the first rib to the pleura, and by fibrous bands which pass to the 
tissue about the subclavian sheath, trachea, and oesophagus (Fig. 985). 
The Costal Pleura (pleura costalis) (Fig. 983) is the shortest portion of the 
pleura and is connected to the parts it covers by the endothoracic fascia (jascia 
endothoracica), a layer of connective tissue which is much thicker back of the rib 
cartilages than it is posteriorly. 'The costal pleura covers the inner surface of part 
of the sternum, the costal cartilages, ribs, and Intercostal muscles, and the sides 
of the bodies of the dorsal vertebrae. This layer is loosely attached except as it 
passes from the heads of the ribs to the vertebrae, where it is firmly adherent. 
The Mediastinal Pleura (pleura mediastinalis) (Fig. 985) covers the septum of the 
mediastinum, which intervenes between the two pleural cavities. The mediastinal 
pleura extends from the inner surface of the anterior wall of the thorax to the 
vertebrae. It is continuous in front and back with the costal pleura of the same 
side, the lines of junction being known, respectively, as the anterior line of pleural 
reflection and the posterior line of pleural reflection. Below the mediastinal pleura 
passes into the diaphragmatic pleura of the same side. The portion of the medi- 
astinal pleura which fuses with the parietal layer of the pericardium is called the 
pericardial pleura (pleura pericardiaca). 
Above the root of the lung the mediastinal pleura passes back directly to the 
vertebrae. "In this region the left mediastinal pleura is applied to the arch of the 
aorta and the phrenic and vagus nerves; to the left innominate vein, the left 
superior intercostal vein, and the left common carotid, and left subclavian arteries; 
to the oesophagus and the thoracic duct. The right mediastinal pleura, on the other 
hand, is applied, above the level of the root of the lung, to the upper part of the 
vena cava and right innominate vein; to the right innominate artery; to the vena 
azygos major, as it hooks forward above the bronchus; to the vagus and phrenic THE ORGANS OF VOICE AND RESPIRATION 
1386 
nerves; and to the right side of the trachea."1 Upon the pericardium the phrenic 
nerve is covered by the pleura. Back of the root of the lung and the pulmonary 
ligament, the right mediastinal pleura passes back to the vertebrae to the left of the 
oesophagus; the left mediastinal pleura passes back over the descending aorta, 
and just above the Diaphragm and in front of the aorta over the lower end of the 
oesophagus. 
The Diaphragmatic Pleura {pleura diaphragmatica} (Figs. 987 and 988) covers 
the upper surface of the Diaphragm outside of the base of the pericardium, but 
does not completely cover it; for it does not pass into the interval between the 
wall of the thorax and Diaphragm, and before this point is reached becomes 
continuous with the costal pleura. 
The reflection to the costal pleura begins by the sternum, at the lower margin of 
the sixth rib; takes place at the junction of the cartilage of the rib with the seventh 
rib; posteriorly, it takes place at the lower margin of the twelfth dorsal vertebra. 
In the front of the chest, where the parietal layer of the pleura is reflected back- 
ward to the pericardium, the two pleural sacs are in contact for a considerable 
extent. At the upper part of the chest, behind the manubrium, they are not in 
contact; the point of reflection being represented by a line drawn from the sterno- 
clavicular articulation to the mid-point of the junction of the manubrium to the 
body of the sternum. From this point the two pleurae descend in close contact to 
the level of the fourth costal cartilages Here the line of reflection on the right side 
is continued downward in nearly a straight line to the lower end of the gladiolus and 
then turns outward behind the costal cartilage of the sixth rib, continuing to 
descend and to run outward, it passes behind the descending part of the seventh 
costal cartilage, and meets the axillary line at the junction of the eighth rib with 
the cartilage. The line of reflection continues to descend till it reaches its lowest 
point at the tenth rib. 'Phis point is in the axillary line, while on the left side 
the line of reflection diverges outward, so that opposite the seventh cartilage it is 
about three-quarters of an inch from the left border of the sternum. It, how- 
ever, always extends considerably farther over the pericardium than the corre- 
sponding lung. From this joint the reflections of the two sides are practically 
the same. The lower limit of the pleura is on a considerably lower level than 
the lower limit of the lung, but does not extend to the attachment of the Dia- 
phragm, so that below the line of reflection of the pleura from the chest wall 
on to the Diaphragm the latter is in direct contact with the rib cartilages and 
the Internal intercostal muscles. In ordinary inspiration the thin margin of the 
base of the lung does not extend as low as the line of pleural reflection, with the 
result that the costal and diaphragmatic pleura are here in contact, the narrow 
slit between the two being termed the phrenico-costal sinus (sinus phrenicocos- 
talis) (Fig. 987). A similar condition exists behind the sternum and rib cartilages, 
where the anterior thin margin of the lung falls short of the line of pleural reflec- 
tion, and where the slit-like cavity between the two layers of pleura forms what is 
sometimes called the costo-mediastinal sinus (sinus costomediastinalis). 
Along the line of reflection of the diaphragmatic pleura a dense fascia passes 
from the costal cartilages and the uncovered portion of the Diaphragm to the 
costal pleura. This serves to hold it in place. It is named by Cunningham the 
phrenico-pleural fascia. 
The inner surface of the pleura is smooth, polished, and moistened by a serous 
fluid; its outer surface is intimately adherent to the surface of the lung, and to the 
pulmonary vessels as they emerge from the pericardium; it is also adherent to the 
upper surface of the Diaphragm; throughout the rest of its extent it is somewhat 
thicker, and may be separated from the adjacent parts with extreme facility. 
1 Cunningham's Text-book of Anatomy. THE MEDIASTINAL SPACE OP MEDIASTINUM 
1387 
The right pleural sac is shorter, wider, and reaches higher in the neck than 
the left. 
Structure of the Pleura.-The pleura is composed of connective tissue con- 
taining much elastic tissue, its free surface being covered with flat endothelial cells. 
It is fastened to adjacent structures by subserous areolar tissue. The subserous 
tissue of the visceral pleura is continuous with the areolar tissue of the lung. 
Vessels and Nerves.-The arteries of the pleura are derived from the intercostal, 
the internal mammary, the musculo-phrenic, thymic, pericardiac, and bronchial. 
The veins correspond to the arteries. The lymphatics are very numerous in the 
pleura and subserous tissue. Many of them are in direct communication with the 
pleural cavity by stomata between the endothelial cells. Stomata are absent in 
the mediastinal pleura and over the ribs (I)yskowsky). The lymphatics of the 
visceral layer empty into the superficial pulmonary trunks; the lymphatics of the 
costal pleura empty into the intercostal trunks; of the diaphragmatic pleura, into 
the diaphragmatic trunks; of the mediastinal pleura, into the posterior mediastinal 
glands.1 The nerves are derived from the phrenic and sympathetic (Luschka). 
Kblliker states that nerves accompany the ramification of the bronchial arteries 
in the pleural pulmonalis. 
Surgical Anatomy.-In operations upon the kidney it must be borne in mind that the pleura 
may sometimes extend below the level of the last rib, and may therefore be opened in these 
operations, especially when the last rib is removed, in order to give more room. It is best to 
keep the incision at least one inch below the last rib, enlarging the wound afterward, when the 
finger can be introduced as a guide. 
In wounds of the Diaphragm the pleura may be injured. In operations about the root of 
the neck, especially in the removal of glands and the ligation of the first part of the subclavian 
artery, the pleura may be injured. 
Punctured wounds of the root of the neck are apt to reach the pleura. 
Empyema is a surgical disease. In acute empyema the treatment is drainage. A portion of 
the fifth or sixth rib in the axillary line is removed by subperiosteal resection, the pleura is 
opened, and a tube is introduced. In chronic empyema the lung is contracted and adherent and 
cannot expand; hence drainage will not cure it. It is necessary to perform multiple rib resec- 
tion in order to permit the chest-wall to sink in and obliterate the cavity, which, as the lung 
is unable to expand, it cannot do. The necessary operation may be the operation of Estlander, 
or the operation of Schede, or the operation of Fowler (page 166). 
If a large wound admits suddenly a quantity of air into the pleura, dangerous or fatal pneumo- 
thorax arises, and the lung collapses. This is best met during operations by using the Fell- 
O'Dwyer apparatus for artificial respiration as advised by Matas.2 This apparatus keeps the 
lung expanded, in spite of the entrance of air into the pleural sac. In surgical pneumothorax 
the lung may be sutured to the chest-wall, so as to block the opening. Sometimes, in order to 
arrest dangerous pulmonary bleeding, a surgeon deliberately induces pneumothorax, in hope that 
the collapse of the lung will arrest bleeding. 
When an abscess of the liver is posterior and on the dorsum, transpleural hepatotomy is per- 
formed. A portion of the tenth and eleventh ribs below the angle of the scapula is removed. 
As a rule, the pleura is found obliterated at this point. If it is opened, it is at once sutured or 
closed with gauze packing. The exposed Diaphragm is incised, and, as it is usually adherent 
to the liver, the abscess cavity is entered. If it is not adherent, the liver is exposed and the 
abscess sought for with an aspirating-needle. 
THE MEDIASTINAL SPACE, INTERPLEURAL SPACE OR 
MEDIASTINUM. 
The mediastinum is the space left in the median portion of the chest by the non- 
approximation of the two pleurae. It extends from the sternum in front to the 
spine behind. Within it are the contents of the thorax excepting the lungs. The 
mediastinum may be divided for purposes of description into two parts-an 
upper portion, above the upper level of the pericardium, which is named the 
1 Poirier, Cun6o, and Delamare on the Lymphatics. Translated and edited by Cecil H. Leaf. 
2 Annals of Surgery, April, 1899. 1388 
THE ORGANS OF VOICE AND RESPIRATION 
superior mediastinum (Struthers); and a lower portion, below the upper level of 
the pericardium. This lower portion is again subdivided into three-that part 
which contains the pericardium and its contents, the middle mediastinum; that 
part which is in front of the pericardium, the anterior mediastinum; and that part 
which is behind the pericardium, the posterior mediastinum. 
The Superior Mediastinum (Fig. 989).-The superior mediastinum is that por- 
tion of the interpleural space which lies above the upper level of the pericardium, 
between the manubrium sterni in front and the upper dorsal vertebrae behind. It is 
bounded below by a plane passing backward from the junction of the manubrium 
and gladiolus sterni to the lower part of the body of the fourth dorsal vertebra, 
Fig. 988.-The posterior mediastinum. THE MEDIASTINAL SPACE Oil MEDIASTINUM 
1389 
and laterally by the lungs and pleurae. It contains the origins of the Sterno-hyoid 
and Sterno-thyroid muscles and the lower ends of the Longus colli muscles; the 
arch of the aorta; the innominate, the thoracic portion of the left carotid and sub- 
clavian arteries; the upper half of the superior vena cava and the innominate 
veins, and the left superior intercostal vein; the pneumogastric, cardiac, phrenic, 
and left recurrent laryngeal nerves; the trachea, oesophagus, and thoracic duct; 
the remains of the thymus gland and some lymphatic glands. 
The Anterior Mediastinum (Fig. 983).-The anterior mediastinum is bounded 
in front by the sternum, on each side by the pleura, and behind by the pericardium. 
It is narrow above, but widens out a little below, and, owing to the oblique course 
taken by the left pleura, it is directed from above obliquely downward and to the 
left. Its anterior wall is formed by the left Triangularis sterni muscle and the 
fifth, sixth, and seventh left costal cartilages. It contains a quantity of loose 
areolar tissue, some lymphatic vessels which ascend from the convex surface of the 
liver, two or three lymphatic glands (anterior mediastinal glands), and the small 
mediastinal branches of the internal mammary artery. 
Left Inom- 
inate Vern. 
Left Carotid 
Artery. 
Thymus 
Gland. 
Pneumogastric 
Nerve. 
Pneumogastrrc 
Nerve. 
Internal Mammary 
Artery. 
Right Innom- 
inate Vein. 
1st Rib. 
- Trachea. 
Vertebral 
Artery. 
Left Sublcavian. 
Artery. 
Oesophagus.- 
2nd Rib. 
3rd Rib. 
Fig. 989.-Transverse section through the second dorsal vertebra. (Braune.) 
The Middle Mediastinum (Fig. 983).-The middle mediastinum is the 
broadest part of the interpleural space. It contains the heart enclosed in the 
pericardium, the ascending aorta, the lower half of the superior vena cava, with 
the vena azygos major opening into it, the bifurcation of the trachea and the two 
bronchi, the pulmonary artery dividing into its two branches and the right and 
left pulmonary veins, the phrenic nerves, and some bronchial lymphatic glands. 
The Posterior Mediastinum (Figs. 983 and 987).-The posterior mediastinum 
is an irregular triangular space running parallel with the vertebral column; it is 
bounded in front by the pericardium and roots of the lungs, behind by the verte- 
bral column from the lower border of the fourth dorsal vertebra, and on either 
side by the pleura. It contains the descending thoracic aorta, the greater and 
lesser azygos veins, the pneumogastric and splanchnic nerves, the oesophagus, 
thoracic duct, and some lymphatic glands. 1390 
THE ORGANS OF VOICE AND RESPIRATION 
Blood-vessels.-The areolar tissue of the anterior mediastinum receives numer- 
ous mediastinal branches from the internal mammary artery. The areolar tissue 
of the posterior mediastinum receives mediastinal branches from the descending 
thoracic aorta. The lowest mediastinal vessels lie upon the Diaphragm and are 
called superior phrenic arteries. The vena cava and internal mammary veins 
receive mediastinal branches. 
The anterior mediastinal lymphatic glands are in the upper portion of the anterior 
mediastinum. They are five or six in number and are placed in front of the trans- 
verse arch of the aorta. Chains of glands run up from them to the root of the 
neck. On the right side glands are in front of the right innominate vein, between 
the artery and vein and behind the artery. On the left side they are around the 
left common carotid and left subclavian arteries.1 
The posterior mediastinal glands are around the oesophagus, particularly in front 
of it. The peritracheo-bronchial glands have been described. 
THE LUNGS (PULMONES) (Figs. 983, 990, 991, 992, 993, 994, 995). 
The lungs are the essential organs of respiration; they are two in number, 
placed one on each side of the chest, separated from each other by the heart and 
other contents of the mediastinum. A healthy lung hangs free within the pleural 
GROOVE FOR 
INNOMINATE VEIN 
LINE OF REFLECTION 
OF PULMONARY 
PLEURA ON TO 
ROOT OF LUNG 
HILUM 
OF LUNG" 
ANTERIOR- 
border' 
LIGAM ENTUM 
LATUM PULMONIS 
Fig. 990.-The right lung. The inner or mediastinal surface, with the hilum laid bare by the removal of the 
structures forming the root of the lung. (Toldt.) 
cavity. It is suspended by the root and by the ligamentum pulmonis. In many 
cases examined the lung does not hang free, but, as a result of former pleurisy, 
an area of the pulmonary pleura is adherent to the parietal pleura. Each lung is 
conical in shape, and presents for examination an apex, a base, two borders, and 
two surfaces. 
The Apex (apex pulmonis).-The apex forms a tapering cone which extends 
into the root of the neck about an inch to two inches above the level of the anterior 
1 Poirier, Cun6o, and Delamare on the Lymphatics. Translated and edited by Cecil H. Leaf. THE LUNGS 
1391 
extremity of the first rib. The brachial plexus is in close proximity to this por- 
tion of the lung. 
The Base (basis pulmonis').-The base is broad, concave, and rests, by its 
diaphragmatic surface (facies diaphragmatica), upon the convex surface of the 
Diaphragm, which separates the right lung from the upper surface of the right 
lobe of the liver and the left lung from the upper surface of the left lobe of the 
liver, the fundus of the stomach, and spleen; its circumference is thin, and 
projects for some distance into the phrenico-costal sinus of the pleura, between 
the lower ribs and the costal attachment of the Diaphragm, extending lower 
down externally and behind than in front. 
Surfaces. The External, Costal or Thoracic Surface (facies costalis) (Figs. 994 
and 995).-The external, costal, or thoracic surface is smooth, convex, of con- 
siderable extent, anti corresponds to the form of the cavity of the chest, being 
deeper behind than in front. In a hardened specimen this surface has grooves 
and bulgings on it, corresponding to the ribs and intercostal spaces. 
ROOT OF 
LUNG 
PULMONARY 
ARTERY 
SUBCLAVIAN 
GROOVE 
BRONCHUS 
AORTIC 
GROOVE 
PULMONARY 
VEINS 
BRONCHIAL 
ARTERIES 
BRONCHIAL 
LYMPHATIC* 
GLAND 
CARDIAC 
DEPRESSION 
LIGAMENTUM 
LATUM 
PULMONIS 
INFERIOR 
BORDER 
Fig. 991.-The left lung. The inner or mediastinal surface, with the root of the lung cut across. (Toldt.) 
The Inner or Mediastinal Surface (facies mediastinalis) (Figs. 990 and 991).-The 
inner or mediastinal surface is concave. It presents in front a depression corre- 
sponding to the convex surface of the pericardium, and behind a deep fissure, the 
hilum (hilus pulmonalis). In the hilum lie the bronchi, vessels, nerves, and 
lymph-nodes, which together constitute the root of the lung. On the inner and 
anterior surface, a little below the apex, is a groove, the subclavian groove (sulcus 
subclavius), for the subclavian artery. A little lower is a broader and shallower 
groove for the innominate and subclavian veins. The pleura lies between the 
lungs and these vessels. In front of the hilum and below it is a depression for 
the heart (impressio cardiaca). It is deeper on the left than on the right side. 
On the right side it passes into the groove from the superior vena cava and the 
vena azygos major. On the left side, behind the hilum, is a groove for the 
thoracic aorta; on the right side a groove for the oesophagus. 1392 
THE ORGANS OF VOICE AND RESPIRATION 
Borders. The Inferior Border (margo inferior).-The inferior border is the line 
of junction of the costal and diaphragmatic surfaces. Posteriorly, it is rounded 
and broad, and is received into the deep concavity on either side of the spinal 
column (Fig. 996). It is much longer than the anterior border, and projects, 
below, into the phrenico-costal sinus. 
Fig. 992.-Front view of the heart and lungs. 
The Anterior Border {margo anterior).-The anterior border is thin and sharp, 
overlaps the front of the pericardium, and is projected into the costo-medi- 
astinal sinus of the pleura. The anterior border of the right lung is almost 
vertical; that of the left presents, below, an angular notch, the incisura cardiaca, 
into which the heart and pericardium are received. A projection from the 
upper lobe comes forward beneath the cardiac notch; it is called the lingula 
pulmonis. 
The Lobes of the Lungs (Figs. 994 and 995).-Each lung is divided into two 
lobes, an upper {lobus superior) and a lower {lobus inferior), by a long and deep 
fissure {incisura interlobaris), which extends from the upper part of the posterior 
border of the organ about three inches from its apex, downward and forward to 
the lowest part of the lung just external to its anterior border. This fissure pene- 
trates nearly to the root. The upper lobe is the smaller; the lower lobe is the 
larger. In the right lung the upper lobe is partially subdivided by a second and 
shorter fissure, which extends almost horizontally forward from the middle of 
the preceding to the anterior margin of the organ, marking off a small triangular 
portion, the middle lobe {lobus medius). 
The right lung is the larger and heavier; it is broader than the left, owing to 
the inclination of the heart to the left side; it is also shorter by an inch, in THE LUNGS 
1393 
consequence of the Diaphragm rising higher on the right side to accommodate 
the liver. 
ENTRANCE OF 
VENA AZYGOS 
BRANCH OF PUL- 
MONARY ARTERY 
LEFT 
VENTRICLE 
LEFT 
AURICLE 
GREAT COSo 
VE"V 
Fig. 993.-Pulmonary veins, seen in a dorsal view of the heart and lungs. The lungs have been pulled 
away from the median line, and a part of the right lung has been cut away to display the air-ducts and blood- 
vessels. (Testut.) 
INTERLOBAR FISSURE 
INTERLOBAR FISSURE 
CARDIAC 
NOTCH 
Fig. 994.-The right lung. The outer or costal 
surface. (Toldt.) 
Fig. 995.-The left lung. The outer or costal 
surface. (Toldt.) 
The Root of the Lung (radix pulmonis} (Figs. 990, 991, 992, and 993).-A 
little above the middle of the inner surface of each lung, and nearer its posterior THE ORGANS OF VOICE AND RESPIRATION 
1394 
than its anterior border, is its root, by which the lung is connected to the heart 
and the trachea. The root is formed by the bronchial tube, the pulmonary 
artery, the pulmonary veins, the bronchial arteries and veins, the pulmonary 
plexus of nerves, lymphatics, bronchial glands, and areolar tissue, all of which 
are enclosed by a reflection of the pleura. The root of the right lung lies behind 
the superior vena cava and ascending portion of the aorta, and below the vena 
azygos major. The root of the left lung passes beneath the arch of the aorta 
and in front of the descending aorta; the phrenic nerve and the anterior pulmo- 
nary plexus lie in front of each, and the pneumogastric and posterior pulmonary 
plexus behind each. 
The chief structures composing the root of each lung are arranged in a similar 
manner from before backward on both sides-viz., the two pulmonary veins in 
front; the pulmonary artery in the middle; and the bronchus, together with the 
bronchial vessels, behind. From above downward, on the two sides, their arrange- 
ment differs, thus: 
On the right side their position is-bronchus, pulmonary artery, pulmonary 
veins; but on the left side their position is-pulmonary artery, bronchus, pulmo- 
nary veins. It should be noted that the entire right bronchus does not lie above 
the right pulmonary artery, but only its eparterial branch (see p. 1377), which 
passes to the upper lobe of the right lung; the divisions of the bronchus for the 
middle and lower lobes lie below the artery. 
The weight of both lungs together is about forty-two ounces, the right lung 
being two ounces heavier than the left; but much variation is met with according 
to the amount of blood or serous fluid they may contain. The lungs are heavier 
in the male than in the female, their proportion to the body being in the former 
as 1 to 37, in the latter as 1 to 43. The specific gravity of the lung-tissue varies 
from 0.345 to 0.746, water being 1.000. 
The color of the lungs at birth is a pinkish-white; in adult life a dark slate- 
color, mottled in patches; and as age advances this mottling assumes a black 
color. 'Fhe coloring matter consists of granules of a carbonaceous substance 
deposited in the areolar tissue near the surface of the organ. It increases in 
quantity as age advances, and is more abundant in males than in females. The 
posterior surface of the lung is usually darker than the anterior. 
The surface of the lung is smooth, shining, and marked out into numerous 
polyhedral spaces, indicating the lobules of the organ; the area of each of these 
spaces is crossed by numerous lighter lines. 
'Fhe substance of the lung is of a light, porous, spongy texture; it floats in 
water and crepitates when handled, owing to the presence of air in the tissue; it 
is also highly elastic; hence the collapsed state of these organs when they are 
removed from the closed cavity of the thorax. 
The Foetal Lung.-After respiration has been established, the lung fills the 
pleural cavity. In the foetus, as the lung has never been distended with air 
and has never received a large amount of blood, it is gathered into a small 
mass at the back of the thorax. It will sink in water and feels solid to the 
touch. 
Structure.-The structure of the lung is such that the blood brought by the 
pulmonary artery comes into close relation with the air which enters from the 
bronchioles. The blood gives materials to the air, and the air gives elements to 
the blood, and the process of respiration causes the dark blood brought from the 
heart by the pulmonary artery to return to the heart as red blood in the pulmonary 
vein. 'Fhe lungs are composed of an external serous coat, a subserous areolar tissue, 
and the pulmonary substance or parenchyma. 
The Serous Coat.-The serous coat is thin, transparent, and invests the entire 
organ as far as the root. It is known as the pulmonary pleura (p. 1384). THE LUNGS 
1395 
The Subserous Areolar Tissue.-The subserous areolar tissue contains a large 
proportion of elastic fibres; it invests the entire surface of the lung, and extends 
inward between the lobules, and at the hilum forms the pulmonary scaffold or 
framework. 
The Parenchyma.-The parenchyma is composed of lobules which, although 
closely connected together by an interlobular areolar tissue, are quite distinct from 
one another, and may be teased asunder without much difficulty in the foetus. 
The lobules vary in size; those on the surface are large, of pyramidal form, with 
the bases turned toward the surface; those in the interior are smaller and of various 
forms. Each lobule is composed of one of the ramifications of a bronchial tube 
and its terminal air-cells, and of the ramifications of the pulmonary and bronchial 
vessels, lymphatics, and nerves, all of these structures being connected together by 
areolar tissue. 
The Bronchus (pp. 1377 and 1378) (Figs. 980, 981, and 982).-The bronchus, 
upon entering the substance of the lung, divides and subdivides bipinnately, 
throughout the entire organ. Sometimes three branches arise together, and occa- 
sionally small lateral branches are given off from the sides of a main trunk. Each 
of the smaller subdivisions of the bronchi enters a pulmonary lobule, and is termed 
a lobular bronchial tube or bronchiole (bronchioli). Each bronchiole divides into 
minute branches (bronchioli respiratorii), the walls of which now begin to present 
irregular dilatations, bronchial alveoli. These are present at first sparingly and on 
one side of the tube only, but as it proceeds onward these dilatations become more 
numerous and surround the tube on all sides, so that it loses its cylindrical char- 
acter. The terminal branches come from the bronchioli respiratorii. These 
terminal branches are called the alveolar ducts or alveolar passages (ductuli alveo- 
lares). The alveolar ducts show numerous alveoli (Fig. 981) and join with cav- 
ities called atria. Each atrium joins several larger cavities, the air-cells or air-sacs 
(injundibula). The numerous small cavities on the surface of the air-sacs are 
the pulmonary alveoli (alveoli pulmonis). The bronchiole now becomes widened 
out and terminates in an irregular cul-de-sac, the air cell, air sac alveolus or infun- 
dibulum. The walls of the infundibulum are closely beset in all directions by pul- 
monary alveoli or pulmonary air cells. Professor Gerrish remarks that the first of 
the alveoli seen on the bronchioles before the coreal ends are formed would seem 
an effort on the part of nature to form an infundibulum before all the necessary 
conditions are favorable. 
Changes in the Structure of the Bronchi in the Lungs.-Within the lungs the 
bronchial tubes are circular, not flattened (Fig. 982), and present certain pecu- 
liarities of structure. 
In the Lobes of the Lungs.-In the lobes of the lungs the following changes 
take place: The cartilages are not imperfect rings, but consist of thin laminae, 
of varied form and size, scattered irregularly along the sides of the tube, being 
most distinct at the points of division of the bronchi. They may be traced into 
tubes, the diameter of each of which is only one-fourth of a line. Beyond this 
point the tubes are wholly membranous. The fibrous coat is continued into the 
smallest ramifications of the bronchi. The muscular coat is disposed in the form 
of a continuous layer of annular fibres, which may be traced upon the smallest 
bronchial tubes, and consists of the unstriped variety of muscular tissue. The 
mucous membrane lines the bronchi and their ramifications throughout, and is 
covered with columnar ciliated epithelium. 
In the Lobules of the Lung.-In the lobular bronchial tubes and in the infun- 
dibula the following changes take place: The muscular tissue begins to disap- 
pear, so that in the infundibula there is scarcely a trace of it. The fibrous coat 
becomes thinner, and degenerates into areolar tissue. The epithelium becomes 
non-ciliated and flattened. This occurs gradually; thus, in the lobular bronchioles 1396 
THE ORGANS OF VOICE AND RESPIRATION 
patches of non-ciliated flattened epithelium may be found scattered among the 
columnar ciliated epithelium; then these patches of non-ciliated flattened epithe- 
lium become more and more numerous, until in the infundibula and air-cells all 
the epithelium is of the non-ciliated pavement variety. In addition to these flat- 
tened cells, there are small polygonal granular cells in the air-sacs, in clusters of 
two or three, between the others. 
The air-cells are small, polyhedral recesses composed of a fibrillated connec- 
tive tissue and surrounded by a few involuntary muscular and elastic fibres. Free 
in their cavity are to be seen under the microscope granular, rounded, amoeboid 
cells (eosinophile leukocytes), often containing carbonaceous particles. The air- 
cells are well seen on the surface of the lung, and vary from to of an 
inch in diameter, being largest on the surface at the thin borders and at the apex, 
and smallest in the interior. 
Mucous Glands.-In the larger bronchi the mucous membrane contains goblet 
cells. When the tubes diminish to 1 mm. in diameter the glands grow fewer. 
In the smaller bronchi there are no mucous glands. 
Vessels of the Lungs.-The pulmonary artery (Figs. 992 and 993) conveys the 
venous blood to the lungs; it divides into branches which accompany the bronchial 
tubes, and terminates in a dense capillary network upon the walls of the inter- 
cellular passages and air-cells. In the lung the branches of the pulmonary artery 
are usually above and in front of a bronchial tube, the vein below. 
The pulmonary capillaries form plexuses which lie immediately beneath the 
mucous membrane in the walls and septa of the air-cells and of the infundibula. 
In the septa between the air-cells the capillary network forms a single layer. The 
capillaries form a very minute network, the meshes of which are smaller than the 
vessels themselves;1 their walls are also exceedingly thin. The arteries of neigh- 
boring lobules are independent of each other, but the veins freely anastomose 
together. 
The pulmonary veins commence in the pulmonary capillaries, the radicles 
coalescing into larger branches, which run along through the substance of the 
lung, independently from the minute arteries and bronchi. After freely commu- 
nicating with other branches they form large vessels, which ultimately come into 
relation with the arteries and bronchial tubes, and accompany them to the hilum 
of the organ. Finally they open into the left auricle of the heart, conveying 
oxygenated blood to be eventually distributed to all parts of the body by the aorta. 
The bronchial arteries supply blood for the nutrition of the lung. The thoracic 
aorta usually gives off two left bronchial arteries. The single right bronchial 
artery usually arises from the first right aortic intercostal, but sometimes from 
the superior left bronchial artery, or from the aorta. In the root of the lung 
they are posterior to the bronchus, they accompany the bronchial tubes, supply 
the tubes and pulmonary tissue, and give branches to the walls of the larger 
pulmonary vessels, the oesophagus, pericardium, and bronchial glands. Those 
supplying the bronchial tubes form a capillary plexus in the muscular coat, from 
which branches are given off to form a second plexus in the mucous coat. This 
plexus communicates with branches of the pulmonary artery, and empties itself 
into the pulmonary vein. Others are distributed in the interlobular areolar tissue, 
and terminate partly in the deep, partly in the superficial, bronchial veins. Lastly, 
some ramify upon the surface of the lung beneath the pleura, where they form a 
capillary network. There may be but one bronchial artery; there may be three 
or four. 
The bronchial veins are not found in the walls of the very small bronchi. The 
small bronchial veins run along by the front and back of the median sized and 
1 The meshes are only 0.002''' to 0.008'" in width, while the vessels are 0.003'" to 0.005'" (Kiilliker, Human 
Microscopic Anatomy).-Ed. of 15th English edition. THE LUNGS 
1397 
larger tubes, and from two trunks at the root of each lung. These vessels termi- 
nate on the right side in the vena azygos major, and on the left side in the superior 
intercostal or left upper azygos vein. Tracheal and posterior mediastinal veins 
open into the bronchial veins. The venous blood from the smaller tubes passes 
to the pulmonary veins. 
The lymphatics begin in networks about the lobules and form networks about 
the bronchi and beneath the bronchial mucous membrane. The superficial col- 
lecting trunks arise about the lobules and beneath the pleura. According to 
Sappey, the superficial trunks from the upper lobe begin on the costal surface; 
one set passes around the anterior border, another set around the posterior 
border, and a third into the incisura interlobaris. The same observer says that the 
superficial trunks from the middle lobe unites with the trunks from the upper and 
lower lobes; and the superficial trunks from the lower lobe, like those of the upper 
lobe, are in three sets. One set passes around the posterior margin, one around the 
anterior margin, and one into the incisura interlobaris. All of the superficial trunks 
convey lymph to the glands of the hilum. Some of the deep collecting trunks begin 
by the sides of the small bronchi; others course along by the pulmonary veins 
or pulmonary arteries. All of them pass to the glands of the hilum. 'The glands 
of the hilum are in communication with the peritracheo-bronchial glands.1 
Nerves.-The lungs are supplied from the anterior and posterior pulmonary 
plexuses, formed chiefly by branches from the sympathetic and pneumogastric. 
The filaments from these plexuses accompany the bronchial tubes, and are lost 
upon them. Small ganglia are found upon these nerves. 
Surface Form.-The apex of the lung is situated in the neck, behind the interval between the 
two heads of origin of the Sterno-mastoid muscle. The height to which it rises above the clavicle 
varies very considerably, but is generally about one inch. It may, however, extend as much as 
an inch and a half or an inch and three-quarters, or, on the other hand, it may scarcely project 
above the level of this bone. In order to mark out the anterior margin of the lung, a line is 
to be drawn from the apex-point, one inch above the level of the clavicle, and rather nearer the 
posterior than the anterior border of the Sterno-mastoid muscle, downward and inward across 
the sterno-clavicular articulation and first piece of the sternum until it meets, or almost meets, 
its fellow of the other side opposite the articulation of the manubrium and gladiolus. From this 
point the two lines are to be drawn downward, one on either side of the mesial line and close to 
it, as far as the level of the articulation of the fourth costal cartilages to the sternum. From 
here the two lines diverge; the left is to be drawn at first passing outward with a slight inclina- 
tion downward, and then taking a bend downward with a slight inclination outward to the apex 
of the heart, and thence to the sixth costo-chondral articulation. The direction of the anterior 
border of this part of the left lung is denoted with sufficient accuracy by a curved line with its 
convexity directed upward and outward from the articulation of the fourth right costal cartilage 
of the sternum to the fifth intercostal space, an inch and a half below and three-quarters of an 
inch internal to the left nipple. The continuation of the anterior border of the right lung is 
marked by a prolongation of its line from the level of the fourth costal cartilages vertically 
downward as far as the sixth, when it slopes off along the line of the sixth costal cartilage to its 
articulation with the rib. 
The lower border of the lung is marked out by a slightly curved line with its convexity down- 
ward from the articulation of the sixth costal cartilage to its rib to the spinous process of the 
tenth dorsal vertebra. If vertical lines are drawn downward from the nipple, the mid-axillary 
line, and the apex of the scapula, while the arms are raised from the sides, they should intersect 
this convex line, the first at the sixth, the second at the eighth, and the third at the tenth rib. 
It will thus be seen that the pleura extends farther down than the lung, so that it may be 
wounded, and a wound may pass through its cavity into the Diaphragm, and the abdominal 
viscera may be injured without the lung being involved. 
The posterior border of the lung is indicated by a line drawn from the level of the spinous 
process of the seventh cervical vertebra, down either side of the spine, corresponding to the 
costo-vertebral joints as low as the spinous process of the tenth dorsal vertebra. The trachea 
bifurcates opposite the spinous process of the fourth dorsal vertebra, and from this point the two 
bronchi are directed outward. 
"The position of the great fissure of the lungs may be indicated by a line drawn from the third 
1 The Lymphatics, by Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. 1398 
THE ORGANS OF VOICE AND RESPIRATION 
dorsal spine obliquely downward in such a manner as to reach the sixth rib close to the mid- 
clavicular line. The interlobar fissure between the upper and middle lobes of the right lung 
corresponds to a line drawn from the apex of the axilla almost horizontally to the sternum, 
reaching the latter at about the level of the fourth costal cartilage" (Erendrath). 
I 'agus 
Inf. thyroid art. 
Recur, lar. nerve 
P. azygos 
Recur. 
lar. nerve 
Epart, 
bronchus 
Pulm.. 
veins 
Pulm. 
veins 
Great 
coron. vein 
Fig. 996. Thoracic contents seen from behind. (Joessel.) 
Foramen for 
(esophagus 
Surgical Anatomy.-The lungs may be wounded or torn in three ways: (1) By compres- 
sion of the chest, without any injury to the ribs. (2) By a fractured rib penetrating the lung. 
(3) By stabs, gunshot wounds, etc. 77/7? LUNGS 
1399 
The first form, where the lung is ruptured by external compression without any fracture of 
the ribs, is very rare, and usually occurs in young children, and affects the root of the lung- 
i. e., the most fixed part-and thus, implicating the great vessels, is frequently fatal. It would 
seem to be a most unusual injury, and the exact mode of its causation is difficult to understand. 
The probable explanation is that immediately before the compression is applied a deep inspira- 
tion is taken and the lungs are fully inflated; owing then to spasm of the glottis at the moment 
of compression, the air is unable to escape from the lung, the lung is not able to recede, and 
consequently gives way. 
In the second variety, when the wound in the lung is produced by the penetration of a broken 
rib, both the pleura costalis and the pleura pulmonalis must necessarily be injured, and conse- 
quently the air taken into the wounded air-cells may find its way through these wounds into the 
cellular tissue of the parietes of the chest. This it may do without collecting in the pleural cavity; 
the two layers of the pleura are so intimately in contact that the air may pass straight through 
from the wounded lung into the subcutaneous tissue. Emphysema constitutes, therefore, an 
important sign of injury to the lung in cases of fracture of the ribs. Pneumothorax, or air in the 
pleural cavity, is much more likely to occur in injuries to the lung of the third variety; that is 
to say, from external wounds, from stabs and gunshot injuries, in which cases air passes either 
from the wound of the lung or from an external wound into the cavity of the pleura dur- 
ing the respiratory movements. In these cases there is generally no emphysema of the sub- 
cutaneous tissue unless the external wound is small and valvular, so that the air drawn into the 
wound during inspiration is then forced into the cellular tissue around during expiration because 
it cannot escape from the external wound. Occasionally in wounds of the parietes of the chest 
no air finds its way into the cavity of the pleura, because the lung at the time of the accident 
protrudes through the wound and blocks the opening. This occurs where the wound is large, 
and constitutes a so-called hernia of the lung. True hernia of the lung occurs, though very 
rarely, after wounds of the chest-wall, when the wound has healed and the cicatrix sub- 
sequently yields from the pressure of the viscus behind. It forms a globular, elastic, crepi- 
tating swelling, which enlarges during expiratory efforts, falls during inspiration, and disappears 
on holding the breath. Wounds of the lung may produce dangerous or fatal hemorrhage into 
the pleural sac. In many cases the bleeding is spontaneously arrested; in others the surgeon 
must interfere to save life. In some cases air has been admitted by intercostal incision and the 
insertion of a tube, and pulmonary collapse has arrested bleeding. In other cases it is necessary 
to resect portions of several ribs, and stop bleeding by ligatures or suture ligatures. In one 
case of a furious secondary hemorrhage following a gunshot wound, the editor resected several 
ribs, packed the pleural cavity about the lung with sterile gauze, to obtain a base of support, and 
then arrested the bleeding by packing iodoform gauze against the firmly supported lung. This 
patient recovered. 
Incision of the lung (pneumotomy) is performed for pulmonary abscess (either tuberculous or 
pyogenic), pulmonary gangrene, hydatid cysts, and bronchiectasis. In pulmonary abscess, 
locate the area by physical signs and the x-ray, resect a portion of a rib over it, and note if the 
pleura is adherent. If it is adherent, continue the operation. If it is not adherent, insert stitches 
of catgut through the two layers of pleura and the superficial part of the lung, so as to encircle 
a considerable area, and then wait several days for adhesions to form. Adhesions protect the 
pleura from infection, and, by keeping air from the pleural sac, prevent pneumothorax. When 
ready to continue the operation, locate the abscess with an aspirating-needle and syringe, open 
it with a cautery at a dull-red heat, and drain by means of a tube. 
Pneumotomy is very unsatisfactory in tuberculous cavities and bronchiectasis. In tubercu- 
losis, excision of the diseased area (pneumectomy) has been employed, but it is not to be advised. THE DUCTLESS GLANDS. 
THESE glands do not possess excretory ducts. They furnish materials which 
are added to the blood or lymph as it passes through them. The material 
from each gland is known as an internal secretion. Some of these secretions are 
powerful materials and influence profoundly the body nutrition. The ductless 
glands are usually given as follows: the spleen, the lymphatic glands, the pineal 
gland, the pituitary body, the suprarenal capsules, the thyroid gland, the para-thyroids, 
the thymus, the carotid body, and the coccygeal body. The lymphatic glands were 
described in a special section (p. 772). The lymphatic glands are not con- 
sidered to be really glands, but, nevertheless, as lymph passes through the lymph 
glands, it receives a product of the glands, namely, lymphocytes. There is no 
evidence that the spleen furnishes an active internal secretion, and this organ 
has been studied with the abdominal viscera. The pineal gland (p. 905) and 
pituitary body (p. 882) were considered with the brain. The suprarenal capsules 
(p. 1428) are described with the kidneys. Some glands, for instance, the liver, 
pancreas and testicle, have an external secretion and also an internal secretion. 
THE THYROID BODY OR GLAND (GLANDULA THYREOIDEA) 
(Fig. 997). 
The thyroid gland is an extremely vascular body, situated at the front and 
sides of the neck, and extending upward upon each side of the larynx. It is a 
single gland, varying greatly in size in different individuals. It is larger relatively 
in females and in children than in men. It is frequently asymmetrical. In early 
embryonal life the gland has a duct, the thyro-glossal duct {ductus thyreoglossus\ 
which passes from the isthmus of the thyroid to the foramen caecum of the dorsum 
of the tongue. The lumen of this duct is obliterated early and becomes a cord of 
epithelium. The lower portion of the duct often remains open for a little way. 
The upper portion remains as the foramen caecum. The situation of this obliter- 
ated foetal duct may be marked by the third or middle lobe of the thyroid gland. 
The thyroid surrounds the upper portion of the trachea like a horseshoe. It con- 
sists of two lateral lobes connected across the middle line by a narrow transverse 
portion, the isthmus. 
The weight of the gland is somewhat variable, but is usually about one ounce. 
It is somewhat heavier in the female, in whom it becomes enlarged during men- 
struation and pregnancy. As age advances the weight of the thyroid diminishes. 
The color of the thyroid, as seen from the surface, is reddish-blue. The gland is 
surrounded by a closely adherent thin connective-tissue capsule of the pre-tracheal 
layer of deep cervical fascia. From the inner surface of the capsule come delicate 
septa, which enter into the thyroid body and separate it into lobes and also sepa- 
rate the lobes into lobules. The blood-vessels lie beneath the capsule. The ante- 
rior and lateral portions of the gland are covered by the capsule. " Passing around 
the side of the gland to its posterior surface, this capsule then splits into two por- 
tions. One remains in contact with the gland and invests its posterior surface. 
The other, the thicker of the two, passes to the posterior surface of the pharynx 
1401 1402 
THE DUCTLESS GLANDS 
and oesophagus, thus enclosing them with the larynx, trachea, and thyroid gland, 
in a common sheath."1 
The lateral lobes are conical in shape, the apex of each being directed upward 
and outward as far as the junction of the middle with the lower third of the thy- 
roid cartilage; the base looks downward, and is on a level with the fifth or sixth 
tracheal ring. The summit of the lateral lobe not unusually is pointed and reaches 
to the level of the oblique line upon the ala of the thyroid cartilage or even higher. 
The right is, as a rule, somewhat larger than the left lobe. The lower portion of 
the gland, when the head is extended, is about 
one inch above the upper margin of the ster- 
num; when the head is flexed, it is at the level 
of the upper border of the sternum or even 
below and behind it. The portion of the 
lateral lobe above the level of the superior 
border of the isthmus is called the upper horn, 
the portion below the level of the inferior mar- 
gin of the isthmus is called the lower horn. The 
lower horn "is usually much smaller than the 
upper horn; frequently it is altogether absent."2 
At the inner and posterior part of each lateral 
lobe is the hilum. At the hilum the inferior 
thyroid artery passes into the gland. "Here 
the recurrent laryngeal nerve comes into close 
contact with the gland, lying in the space be- 
tween it and the trachea and oesophagus."3 
The external or superficial surface is convex, 
and covered by the skin, the superficial fascia, 
the deep fascia, the Sterno-mastoid, the anterior 
belly of the Omo-hyoid, the Sterno-hyoid and 
Sterno-thyroid muscles, and beneath the last- 
named muscles by the pre-tracheal layer of the 
deep fascia, which forms a capsule for the 
gland. 
The deep or internal surface is moulded 
over the underlying structures-viz., the thy- 
roid and cricoid cartilages, the trachea, the 
inferior constrictor and posterior part of the 
Crico-thyroid muscles, the oesophagus (par- 
ticularly on the left side of the neck), the supe- 
rior and inferior thyroid arteries, and the recurrent laryngeal nerves. 
The deep surface of each lobe is fixed by bands of fibrous tissue passing from 
the capsule of the isthmus and lateral lobes to the sides of the cricoid cartilage and 
the posterior fascia of the trachea. These bands are called the lateral or suspen- 
sory ligaments. Because of this fixation to the larynx and trachea by the capsule 
and by the lateral ligaments, the thyroid gland moves with the trachea and ascends 
during the act of swallowing. The recurrent laryngeal nerve on each side is in 
contact with the outer and posterior surface of the suspensory ligament. 
The anterior border is thin, and inclines obliquely from above downward and 
inward toward the middle line of the neck, while the posterior border is thick and 
overlaps the common carotid artery. Each lobe is about two inches in length, its 
greatest width is about one inch and a quarter, and its thickness about three- 
quarters of an inch. The posterior border is over the common carotid artery and 
Fig. 997.-The thyroid gland. (Spalteholz.) 
1 Diseases of the Thyroid Gland. By James Berry. 2 Ibid. 3 Ibid. THE THYROID BODY OR GLAND 
1403 
touches the oesophagus and pharynx. The carotid artery usually makes a groove 
upon the gland. 
The Isthmus {isthmus glandulae thyreoided).-The isthmus connects the lower 
third of the two lateral lobes; it measures about half an inch in breadth and the 
same in depth, and usually covers the second and third rings of the trachea, but 
sometimes also the first and fourth rings. Its situation presents, however, many 
variations, a point of importance in the operation of tracheotomy. In the middle 
line of the neck it is covered by the skin and fascia, and close to the middle line, 
on either side, by the Sterno-hyoid muscle. Across its upper border run branches 
of the superior thyroid artery and vein; at its lower border is a branch of the 
inferior thyroid veins. Sometimes the isthmus is altogether wanting, the two 
lateral lobes being completely separate. 
The third, pyramidal or middle lobe is called the pyramid of Lalouette. It is not 
constant, but is frequently found. Occasionally it arises from the upper part of 
the isthmus, or from the adjacent portion of either lobe, but most commonly from 
the left lobe, and ascends in front of the thyroid cartilage in the direction of the 
middle of the hyoid bone. It may reach the bone or may not reach it. If it 
reaches the bone it is attached to it. If it does not reach the bone, fibrous tissue, 
which often contains muscle, is prolonged from the tip of the pyramid to the 
back of the bone or to the thyro-hyoid membrane. The pyramid is occasionally 
quite detached, or divided into two or more parts, or altogether wanting, 
A few muscular bands, derived from the Thyro-hyoid muscles, are occasionally 
found attached, above, to the body of the hyoid bone, and below to the isthmus 
of the gland or its pyramidal process. These form a muscle, which was named 
by Soemmerring the Levator glandulae thyreoidae. 
Accessory Thyroids {glandulae thyreoideae accessoriae}.-Frequently small 
isolated masses of thyroid tissue exist. They are found particularly about the 
lateral lobes of the thyroid gland in the sides of the neck or just above the hyoid 
bone, and are called accessory thyroids. Accessory thyroids may also exist by the 
side of the pyramidal lobe or upon the trachea, as low even as the level of the arch 
of the aorta. These isolated portions of gland tissue represent isolated portions 
of the median thyroid rudiment. Sometimes accessory thyroid tissue is found 
in the root of the tongue or in the interior of the larynx. Berry points out that a 
distinction must be made between true congenital accessory thyroids and masses 
of encapsuled thyroid tissue which "have been extruded from the gland." 
Structure of the Thyroid (Fig. 998).-The thyroid body is invested by a thin 
capsule of connective tissue which projects into its substance as a framework and 
imperfectly divides it into masses of irregular form and size, known as lobules. 
More slender septa separate the secretory alveoli from one another. When the 
organ is cut into, it is of a brownish-red color, and is seen to be made up of a 
number of closed vesicles or alveoli containing a yellow glairy fluid and separated 
from each other by intermediate connective tissue. 
According to Baber, who has published some important observations on the 
minute structure of the thyroid,1 the vesicles of the thyroid of the adult animal 
are generally closed cavities; but in some young animals {e. g., young dogs) the 
vesicles are more or less tubular and branched. This appearance he supposes 
to be due to the mode of growth of the gland, and merely indicating that an 
increase in the number of vesicles is taking place. Each vesicle is lined by a single 
layer of epithelium, the cells of which are cubical or cylindrical. Between the 
epithelial cells exists a delicate reticulum. The vesicles are of various sizes and 
shapes, and contain as a normal product a viscid, homogeneous, semi-fluid, 
slightly yellowish material which frequently contains blood, the red corpuscles of 
1 Researches on the Minute Structure of the Thyroid Glands, Phil. Trans., part iii., 1881 THE DUCTLESS GLANDS 
1404 
which are found in it in various stages of disintegration and decolorization, the 
yellow tinge being probably due to the luemoglobin, which is thus set free from 
the colored corpuscles. This normal product is known as colloid material, and it 
is secreted by the epithelium. What part if any the colloid plays in the formation 
of the internal secretion of the gland is not known. It is quite possible that the 
colloid corresponds to the external secretion of glands with ducts and that the 
true internal secretion passes directly into the capillaries which form a network 
about the alveoli (Szymonowicz), or passes into the lymphatics. In the thyroid 
gland of the dog, Baber has found large round cells, parenchymatous cells, each 
provided with a single oval-shaped nucleus, which migrate into the interior 
of the gland-vesicles. Between the thyroid vesicles in the human being are col- 
lections of round cells. They are, in reality, miniature vesicles, and are much 
more numerous in youth than in old age. 
The capillary blood-vessels form a dense plexus in the connective tissue around 
the vesicles, between the epithelium of the vesicles and the endothelium of the 
lymph-spaces, which latter surround a greater or smaller part of the circumference 
Lymphatic vessel. 
Vesicle. 
Artery. 
Fig. 998.-Minute structure of the thyroid. From a transverse section of the thyroid of a dog. Semi- 
diagrammatic. (Baber.) 
Wall of gland-vesicle. 
of the vesicles. These lymph-spaces empty themselves into lymphatic vessels 
which run in the interlobular connective tissue, not uncommonly surrounding the 
arteries which they accompany, and communicate with a network in the capsule 
of the gland. Small glands may be connected with this network. Baber has 
found in the lymphatics of the thyroid a viscid material which is morphologically 
identical with the normal constituent of the vesicle. 
Vessels and Nerves.-The arteries (Figs. 392 and 393; see also p. 602) supply- 
ing the thyroid are the superior thyroid from the external carotid, and the inferior 
thyroid from the thyroid axis of the first part of the subclavian. Sometimes there 
is an additional vessel, the thyroidea media or ima, usually arising from the 
innominate artery, but sometimes from the arch of the aorta or the common caro- 
tid. It ascends upon the front of the trachea. The superior thyroid artery reaches 
the summit of the upper horn of the gland, and usually at this point gives off a 
vessel which courses down the posterior surface of the gland. The main trunk 
passes downward and inward at the junction of the inner and anterior border of 
the upper horn, giving branches to adjacent structures and sending branches over THE THYROID BODY OR GLAND 
1405 
the anterior surface of the thyroid gland. It reaches the isthmus and crosses 
the isthmus at its upper border to anastomose with the artery from the other side. 
The inferior thyroid artery, which is usually larger than the superior, after it 
has passed posterior to the sheath of the carotid and the sympathetic nerve, reaches 
the posterior surface of the gland. At this point branches are given off; some pass 
into the hilum; the others go to the posterior surface of the gland. The relation 
of the artery to the recurrent laryngeal nerve is very important to the surgeon. 
"Usually the main trunk of the artery passes behind the nerve; sometimes the 
artery breaks up before reaching the nerve; in this case one or more of the branches 
may pass in front of it. Much less commonly the main trunk or all its branches 
will be found to lie in front of the nerve."1 If the thyroidea ima is present it goes 
to the lower part of the gland. The larger branches of the thyroid arteries are 
beneath the capsule and upon the surface of the gland; smaller branches pass to 
the interior of the gland (Berry). The arteries are remarkable for their large 
size and frequent anastomoses. 
The thyroid veins (Figs. 447 and 448; see also p. 731) form a plexus upon the 
surface of the gland and beneath the capsule. Here and there veins pass through 
the capsule and go to adjacent venous trunks. Berry, accepting Kocher's descrip- 
tion, notes the following veins: The superior thyroid vein runs with the superior 
thyroid artery and passes to the internal jugular vein. A transverse vein of the 
upper border of the isthmus joins the two superior thyroid veins. A single vein, 
the middle thyroid, sometimes emerges from the side of the gland and passes to 
the internal jugular. Usually, however, instead of this single vein there are two 
veins, the superior and inferior accessory thyroids. The superior accessory thyroid 
emerges from the outer side of the upper horn, below the apex, and passes to the 
internal jugular. The inferior accessory thyroid emerges from the posterior and 
inferior portion of the gland and passes to the internal jugular. The veins from the 
lower border of the gland vary greatly. A vein passes vertically down on each side 
in front of the trachea from the isthmus and from the inner side of the inferior horn. 
It is called by Kocher the thyroidea ima. The vein of the left side passes to the left 
innominate; the vein of the right side passes to the right innominate or left innom- 
inate. As Berry points out, the vein of one side may be small or may be absent, 
or the two veins may unite and form one vein which enters the left innominate. 
An inferior thyroid vein is often present. It is of small size, emerges at the inferior 
and external part of the gland, and passes to the corresponding innominate vein.2 
The lymphatics are numerous and of large size. Collecting trunks arise from a 
network within the capsule. Some trunks ascend from the upper margin of the 
isthmus and reach the gland in front of the larynx; others ascend along the superior 
thyroid artery and reach the glands at the bifurcation of the carotid. Descending 
trunks from the lower margin of the isthmus reach the glands in front of the 
trachea; trunks from the side of the gland descend to the glands about the recur- 
rent laryngeal nerve.3 
The nerves are derived from the middle and inferior cervical ganglia of the sym- 
pathetic, and from the inferior laryngeal nerves. Probably there is also a branch 
from each superior laryngeal nerve. 
Surgical Anatomy. The thyroid gland may be congenitally absent, and when it is the indi- 
vidual suffers from the worst form of cretinism. One lobe may be congenitally absent, but 
this will provoke no trouble unless the other lobe undergoes atrophy. 
Complete removal of the thyroid and parathyroids will produce operative myxoedema (cachexia 
strumipriva), unless accessory thyroids enlarge and perform the functions of the thyroid. 
The thyroid gland may be congenitally enlarged. The gland tends to atrophy in old age. 
It is atrophied in myxoedema and cretinisin. Some forms of thyroid enlargement are called 
goitre. 
1 Diseases of the Thyroid Gland. By James Berry. 2 Ibid. 
3 The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. 1406 
THE DUCTLESS GLANDS 
When all parts of the gland enlarge the eondition is known as parenchymatous goitre. 
Adenomatous goitre consists of an adenoma or of adenomata. In cystic goitre there is one 
or more cysts due to cystic degeneration of adenomata or to fusion of adjacent follicles. 
A pulsating goitre is one which receives impulses from the carotid pulsations. In a fibroid 
goitre there is increase of interstitial connective tissue. A goitre which passes back of the sternum 
is known as substernal or intrathoracic. A goitre may extend back of the trachea or back of 
the oesophagus. 
Exophthalmic goitre, Graves's disease or Basedow's disease, is a remarkable disease. Its three 
chief symptoms are enlargement of the thyroid, or goitre ; prominence of the eyeballs, or exoph- 
thalmos, and very rapid pulse, or tachycardia. Dyspnoea, tremor, and various other symptoms 
are usually found. The thyroid gland may be the seat of a carcinoma or sarcoma (malignant 
goitre), syphilitic or tuberculous disease, ordinary inflammation, suppuration, or hydatid disease; 
For the relief of ordinary goitre various methods have been employed. Tapping, injection of 
astringents, simple incision, and the seton are obsolete. Ligature of the thyroid arteries is rarely 
performed as a curative measure. The superior and inferior thyroids of one side have been tied 
in some cases; all four thyroids in other cases. Jaboulay has performed exothyropexy. In this 
operation the gland is dislocated from its bed, brought out of the wound, and left exposed, in 
hope that it will atrophy 
Division of the isthmus is occasionally practised to relieve dyspnoea. The operation some- 
times succeeds, but often fails. 
Extirpation of one-half or two-thirds of the gland is a very successful operation. Removal of 
the entire gland with the parathyroids will be followed by operative myxoedema. 
In extirpating a lobe of the thyroid great care must be taken to avoid tearing the capsules, as if 
this happens the gland-tissue bleeds profusely. The thyroid arteries should be ligatured on the 
diseased side before an attempt is made to remove the mass, and in ligaturing the inferior thy- 
roid the position of the recurrent laryngeal nerve must be borne in mind, so as not to include 
it in the ligature. 
A cystic or solid tumor of the thyroid may be removed by intraglandular enucleation. If 
operation becomes necessary in exophthalmic goitre, partial extirpation is usually preferred. 
Bilateral extirpation of the cervical ganglia of the sympa- 
thetic (sympathectomy or Jonnesco's operation) has been 
practised by some surgeons for exophthalmic goitre. The 
value of the procedure is uncertain. 
Parathyroids (Fig. 999).-If the thyroid gland 
has been carefnlly detached, two round bodies 
of small size may be found embedded upon the 
trachea or upon the surface of the lateral lobe of 
the gland, between the terminal branches of the 
inferior thyroid artery. "These are the para- 
thyroids, about the size of orange-seeds, and 
brownish-red in color."1 These masses are con- 
stant in man and are more distinct in infants 
than in adults. Although the parathyroids lie 
on or in the thyroid, they are always completely 
separated from it by capsules of connective 
tissue. The parathyroids are divided from their 
situation into external and internal. The former, 
usually two in number, are situated, one on each 
side, in relation to the postero-internal surface 
of the lateral lobe; sometimes they are duplicated. 
The latter, also usually two in number, are placed 
one in or on each lateral lobe, generally near its 
mesial surface. 
Structure.-The structure of the parathyroids 
is different from that of the thyroid. They are 
composed of solid masses of epithelial cells arranged in a more or less columnar 
fashion with numerous intervening capillaries. The columns of the para- 
Fig. 999.-The position of the parathy- 
roid glands. View from behind. (Zucker- 
kandl.) 
1 Practical Anatomy. By Prof. Alfred W. Hughes. THE THYMUS GLAND 
1407 
thyroids anastomose. There is much lymphoid tissue connected with the 
columns. Some regard the parathyroids as embryonic portions of the thyroid. 
This view seems to gain probability from the statement that after complete 
thyroidectomy, the parathyroids having been left, these structures increase in 
size, and apparently prevent operative myxoedema. If they are also removed, 
myxoedema arises. Nevertheless, MacCallum says "there is no histological proof 
that parathyroid tissue can ever become converted into thyroid tissue." Most 
observers regard the parathyroids as distinct glands possessed of a special func- 
tion. Certain it is, as Gley and others have shown, removal of the parathyroids 
from herbivora leaving the thyroid intact is followed by spasms, tetany, etc., just 
as complete thyroidectomy is followed by such symptoms in carnivora.1 
THE THYMUS GLAND (Fig. 1000). 
The thymus gland is a temporary organ, attaining its full size at the end of the 
second year, when it ceases to grow and remains practically stationary until 
puberty, at which period it rapidly degenerates. It docs not entirely disappear, 
for the shrunken and degenerated mass, even later in life, maintains a likeness to 
the original form and retains within its substance small portions of thymus tissue 
(Waldeyer). If examined when its growth is most active, it will be found to con- 
PN EUMOGASTRIC, 
nerve' 
SUBCLAVIAN 
VEIN 
PHRENIC 
NERVE 
Fig. 1000. -The thymus gland in an infant two months old. (Poirier and Charpy.) 
sist of two lateral lobes placed in close contact along the middle line, situated 
partly in the superior mediastinum, partly in the neck, and extending from the 
level of the fourth costal cartilage upward as high as the lower border of the 
thyroid gland. It is covered by the sternum and by the origins of the Sterno- 
hyoid and Sterno-thyroid muscles. Below, it rests upon the pericardium, being 
1 Internal Secretions. By William Hanna Thomson. New York Medical Journal, November 19, 1904. THE DUCTLESS GLANDS 
1408 
separated from the arch of the aorta and great vessels by a layer of fascia. In the 
neck it lies on the front and sides of the trachea, behind the Sterno-hyoid and 
Sterno-thyroid muscles. The two lobes generally differ in size; they are occa- 
sionally united so as to form a single mass, and are sometimes separated by an 
intermediate lobe. The thymus is of a pinkish-gray color, is soft and is lobu- 
lated on its surfaces. It is about two inches in length, one and a half inches 
in breadth below, and about three or four lines in thickness. At birth it weighs 
about half an ounce. 
Structure (Figs. 1001 and 1002).-Each lateral lobe is composed of numerous 
lobules held together by delicate areolar tissue, the entire gland being enclosed in 
an investing capsule of a similar but denser structure. The primary lobules vary 
in size from a pin's head to a small pea, and are made up of a number of small 
nodules or follicles which are irregular in shape and are more or less fused 
together, especially toward the interior of the gland. Each follicle consists of a 
medullary and cortical portion,which differ in many essential particulars from each 
other. The cortical portion is mainly composed of lymphoid cells supported by a 
delicate reticulum. In addition to this reticulum, of 
which traces only are found in the medullary portion, 
there is also a network of finely branched cells which 
is continuous with a similar network in the medul- 
lary portion. This network forms an adventitia to 
the blood-vessels. In the medullary portion there 
are but few lymphoid cells, but there are, especially 
toward the centre, granular cells and concentric 
corpuscles. The granular cells are rounded or 
flask-shaped masses attached (often by fibrillated 
extremities) to blood-vessels and to newly formed 
connective tissue. The concentric corpuscles are 
composed of a central mass consisting of one or 
more granular cells, and of a capsule which is 
formed of epithelioid cells which are continuous 
with the branched cells forming the network men- 
tioned above. 
Each follicle is surrounded by a capillary plexus 
from which vessels pass into the interior and radiate 
from the periphery toward the centre, and form a 
second zone just within the margin of the medullary 
portion. In the centre of the medulla there are very 
few vessels, and they are of minute size. 
Watney has made the important observation that 
haemoglobin is found in the thymus either in cysts 
or in cells situated near to or forming part of the 
concentric corpuscles. This haemoglobin varies 
from granules to masses exactly resembling colored blood-corpuscles, oval in the 
bird, reptile, and fish; circular in all mammals except in the camel. Dr. Watney 
has also discovered in the lymph issuing from the thymus similar cells to those 
found in the gland, and, like them, containing haemoglobin either in the form of 
granules or masses. From these facts he arrives at the physiological conclusion 
that the thymus is one source of the colored blood-corpuscles. 
Vessels and Nerves.-The arteries supplying the thymus, are derived from 
the internal mammary and from the superior and inferior thyroid. The veins 
terminate in the two innominate veins, and in the internal mammary and the 
thyroid veins. The lymphatics are of large size, arise in the substance of the 
gland, and are said to terminate in the internal jugular vein. The nerves are 
Fig. 1001.-Minute structure of thy- 
mus gland. Upper portion of the 
thymus of a foetal pig of 2" in length, 
showing the bud-like lobuli and gland- 
ular elements. 2, cells of the thymus, 
mostly from a man ; a, free nuclei ; 
b, small cells ; c, larger ; d, larger, with 
oil-globules, from the ox ; e, f, cells 
completely filled with fat, at f without 
a nucleus ; 3, h, concentric bodies ; 0, 
an encapsulated nucleated cell ; h, a 
composite structure of a similar nature. THE CAROTID GLAND OR CAROTID BODY 
1409 
exceedingly minute; they are derived from the pneumogastric and sympathetic. 
Branches from the descendens hypoglossi and phrenic reach the investing cap- 
sule, but do not penetrate into the substance of the gland. 
Vein. 
Artery. 
Concentric 
corpuscle. 
Artery.' 
■Granular cells. 
■Artery. 
■Vein. 
Vein. 
Artery.- 
Fig. 1002.-Minute structure of the thymus gland. Follicle of injected thymus from a calf, four days old, 
slightly diagrammatic, magnified about 50 diameters. The large vessels are disposed in two rings, one of which 
surrounds the follicle, the other lies just within the margin of the medulla. A and B, from thymus of camel, 
examined without addition of any reagent. Magnified about 400 diameters. A, large colorless cell containing 
small oval masses of hsemoglobin. Similar cells are found in the lymph-glands, spleen, and medulla of bone ; 
B, colored blood-corpusclee. (Watney.) 
THE CAROTID GLAND OR CAROTID BODY (GLOMUS CAROTICUM). 
This body, when present, lies in the carotid bifurcation, to the inner side of the 
common carotid below the bifurcation, or on the posterior surface of the internal or 
of the external carotid. It is often absent. It lies in fatty tissue and is surrounded 
by a fibrous capsule which is attached to the carotid sheath. The carotid gland 
is about the size of a grain of corn; it is oval in shape and reddish-brown in color. 
The capsule of the gland sends septa inward. The septa divide the organ into 
follicles or cell-balls. These cell-balls are composed of endothelial cells and are 
associated with blood capillaries. A branch (or branches) from the carotid artery 
enters the carotid gland, and the gland is closely connected with the carotid 
plexus of the sympathetic. (This structure has been recently studied by John 
Funke,1 Reclus and Chevasson,2 Paltauf, Kartschenko, and Marchand.) 
Surgical Anatomy.- Tumors may arise from this structure. Such a tumor is apt to be 
above the level of the upper margin of the thyroid cartilage and in most cases it moves with 
each arterial beat. 
1 American Medicine, vol. viii., No. 3. 2 Bull, et mem. de la Soc. de chir. de Paris, 1903, No. 18. 1410 
THE DUCTLESS GLANDS 
THE COCCYGEAL GLAND OR COCCYGEAL BODY OR LUSCHKA'S 
GLAND (GLOMUS COCCYGEUM). 
Lying near the tip of the coccyx in a small tendinous interval formed by the 
union of the Levator ani muscles and just above the coccygeal attachment of 
the Sphincter ani, is a small conglobate body about as large as a lentil or a pea, 
first described by Luschka,1 and named by him the coccygeal gland. Its most 
obvious connections are with the arteries of the part. It is similar in structure 
to the carotid body. 
Structure.-It consists of a congeries of small arteries with little aneurismal 
dilatations derived from the middle sacral and freely communicating with each 
other. 'These vessels are enclosed in one or more layers of polyhedral granular 
cells, and the whole structure is invested in a capsule of connective tissue which 
sends in trabeculae, dividing the interior into a number of spaces in which the 
vessels and cells are contained. Nerves pass into this little body from the sympa- 
thetic, but their mode of termination is unknown. Macalister believes the glom- 
erulus of vessels "consists of the condensed and convoluted metameric dorsal 
arteries of the caudal segments embedded in tissue which is possibly a small per- 
sisting fragment of the neurenteric canal." It resembles the carotid gland in 
structure, and is probably one of the ductless glands. 
1 Der Hirnanhang und die Steissdruse des Menschen, Berlin, 1860; Anatomie des Menschen, Tubingen, 1864, 
vol. ii. pt. 2, p. 187. THE URINARY ORGANS 
THE KIDNEYS (RENES) (Figs. 1003, 1004, 1005). 
rOHE Kidneys are large glands. They are two in number, and are situated 
1 in the back part of the abdomen, near the spinal column. Their function is 
to separate from the blood certain materials which, when dissolved in a quantity 
of water, also separated from the blood by the kidneys, constitute the urine. 
They are placed in the loins, one on each side of the vertebral column, behind 
the peritoneum, and are surrounded by a mass of fat and loose areolar tissue, which 
TERMINAL 
PART OF 
PROSTATE 
VEIN 
ORIGIN OF 
DUCTUS 
CHOLEDOCHUS 
FIBROUS 
CAPSULE 
F LEFT 
SPERMATIC 
ARTERY 
-AND VEIN 
PELVIS OF 
KIDNEY 
RIGHT 
SPERMATIC 
VEIN 
-CELLULO- 
FIBROUS 
SU B PE R ITO N E A L 
LAMINA 
Fig. 1003.-The situation, direction, forms, and supports of the kidney. (Sappey.) 
constitutes the fatty capsule (capsula adiposa) (Figs. 1008 and 1009). There are 
two distinct layers in this fatty capsule. The superficial fatty layer is the pararenal 
fat.1 Keen calls this layer the transversalis layer of fat, because it is derived from the 
transversalis fascia.2 The deeper and thicker perirenal layer is the true perinephric 
fat (Fig. 1009). The deeper layer of fat completely surrounds the kidney, and is 
somewhat adherent to the fibrous renal capsule. The fat about the kidney does 
1 See Gerota, Arch. f. Anatomie. Leipzic, 1895; Zuckerkandl, Medizinische Jahrbiicher, Vienna, 1883. 
3 W. W. Keen, in American Medicine, January 31, 1903. 
1411 1412 
THE URINARY ORGANS 
not look like fat in other regions, but is soft, delicate, and of a canary yellow 
color. These two layers are separated by a layer of connective tissue, which is 
the posterior layer of the perirenal fascia, and is called by Zuckerkandl the retro-renal 
fascia (fascia retrorenalis) (Fig. 1008). The true capsule of the kidney (tunica 
fibrosa) is thin, smooth, and glistening. The inner part of this capsule (tunica 
muscularis) contains unstriated muscle fibres. The true capsule can be easily 
separated from the underlying glandular structure. The upper extremity of the 
kidney is on a level with the upper border of the twelfth dorsal vertebra, the lower 
extremity on a level with the third lumbar vertebra (Fig. 1006). The right kidney 
is usually on a slightly lower level than the left, probably on account of the vicinity 
of the liver. In the female the kidneys are a little lower than in the male. 
Each kidney is about four and a half inches in length, two to two and a half in 
breadth, and rather more than one inch in thickness. The left is somewhat longer, 
though narrower, than the right. The weight of the kidney in the adult male varies 
from 4| ounces to 6 ounces; in the adult female, from 4 ounces to 5| ounces. The 
combined weight of the two kidneys in proportion to the body is about 1 in 240. 
Fig. 1004.-Anterior surface of the kidney. 
(Bourgery.) 
Fig. 1005.-Posterior surface of the kidney. 
(Bourgery.) 
The kidney has the characteristic form of a "flattened bean" (Spalteholz). It 
is flattened on its sides and presents at one part of its circumference a hollow. 
It is larger at its upper than at its lower extremity. The kidney presents for exam- 
ination two surfaces, two borders, and an upper and lower extremity. 
Surfaces. The Anterior Surface facies anterior) (Figs. 1003 and 1004).-Its ante- 
rior surface is convex, looks forward and outward, and is partially covered by peri- 
toneum. The right kidney in its upper three-fourths is in contact with the pos- 
terior part of the under surface of the right lobe of the liver. This area of the right 
kidney is flattened (impressio hepatica). Toward its inner border it is covered by 
the second part of the duodenum, while its lower and outer part is in relation with 
the hepatic flexure of the colon. The relation of the second part of the duodenum 
to the front of the right kidney is a varying one. The left kidney is covered above 
by the posterior surface of the stomach, below the stomach by the pancreas, behind 
which are the splenic vessels. The region in contact with the stomach is markedly 
depressed (impressio gastrica). Its lower half is in contact with some of the coils THE KIDNEYS 
1413 
of the small intestine and sometimes with the third part of the duodenum. Near 
its outer border the anterior surface lies behind the spleen and the splenic flexure 
of the colon. 
Fig. 1006. Posterior surface of the kidneys. (Poirier and Charpy.) 
Fig. 1007.-Relation of the kidney to the vertebral column, ribs, muscles, and lumbo-costal ligaments. 
(Poirier and Charpy.) 1414 
THE URINARY ORGANS 
The kidneys are partly covered in front by peritoneum and partly uncovered. 
On the right kidney, the hepatic area, that is to say that portion of the kidney 
which produces the renal impression on the liver, is covered by peritoneum, which 
therefore separates the kidney from the liver; the duodenal and colic areas are not 
peritoneal, and these structures are connected to the kidney by loose connective 
tissue; at the lower and inner extremity is a small area, the mesccolic area, which 
is covered by a layer of peritoneum of the greater sac and by the colic vessels. 
On the left kidney the gastric area is covered by the peritoneum of the lesser sac; 
the pancreatic and colic areas are non-peritoneal; while, as on the right side, at the 
lower and inner extremity, is an area, mesocolic area, which is covered by the 
peritoneum of the greater sac and by the colic vessels. 
The Posterior Surface (facies posterior) (Fig. 1005).-The posterior surface of the 
kidney is flatter than the anterior and is directed backward and inward. It is 
ELEVENTH 
RIB 
TWELFTH. 
RIB 
SUBPERI- 
TONEAL 
FASCIA 
POSTERIOR 
LAMELLA OF 
PERI REN AL~ 
FASCIA 
PERITONEUM 
VESSELS OF 
HILUM OF 
KIDNEY 
ANTERIOR 
LAMELLA OF 
PERIRENAL 
FASCIA 
FAT BEHIND 
PERIRENAL 
FASCIA 
.SECTION 
OF COLON 
■ PERITON EUM 
TRUE 
PE R I N E PH RITIC 
PARARENAL 
FAT 
SACRO-LU M B A LIS 
GROUP 
QUADRATUS LUM- 
BOPUM MUSCLE 
Fig. 1008.-Longitudinal section, showing the 
arrangement of the capsule of the kidney. 
(After Gerota.) 
Fig. 1009.-Transverse section, showing the relations 
of the capsule of the kidney and the two layers of fat. 
(After Gerota.) 
entirely devoid of peritoneal covering, being embedded in areolarand fatty tissue. 
It lies upon the Diaphragm, the anterior layer of the lumbar aponeurosis, the 
external and internal arcuate ligaments, the Psoas and Transversalis muscles, 
one or two of the upper lumbar arteries, the last dorsal, ilio-hypogastric, and 
ilio-inguinal nerves. The lumbo-costal ligaments overlie the posterior surface of 
the kidney (Fig. 1007). The right kidney rests upon the twelfth rib (Fig.1007), 
the left usually on the eleventh and twelfth ribs. The Diaphragm separates the 
kidney from the pleura as the pleura dips down to form the phrenico-costal sinus 
(Fig. 987), but frequently the muscul*)r fibres of the Diaphragm are defective or 
absent over a triangular area immediately above the external arcuate ligament, 
and when this is the case the perirenal areolar tissue is in immediate apposition 
with the diaphragmatic pleura. In the lower part of the posterior surface of the 
kidney is an impression produced by the Quadratus lumborum muscle and called THE KIDNEYS 
1415 
the impressio muscularis. A little internal to this a flattening, caused by the Psoas 
muscle, is often recognizable. At the upper part of the posterior surface is a sulcus 
produced by contact with the Diaphragm. 
Borders. The External Border (margo lateralis) (Figs. 1004 and 1005).-The 
external border is convex, and is directed outward and backward, toward the 
postero-lateral wall of the abdomen. On the left side it is in contact, at its upper 
part, with the spleen (Fig. 1003). 
The Internal Border (margo medialis) (Figs. 1004 and 1005).-The internal bor- 
der is concave, and is directed forward, inward, and a little downward. It presents 
a deep longitudinal fissure, bounded by a prominent overhanging anterior and 
posterior lip. This fissure is named the hilum (hilus renalis) (Fig. 1010), and 
allows of the passage of the vessels, nerves, and ureter into and out of the kidney. 
Extremities. The Superior Extremity (extremitas superior) (Figs. 1004 and 1005. 
-The superior extremity, directly slightly inward as well as upward, is thick and 
rounded, and is surmounted by the suprarenal capsule (Fig. 1010), which covers 
also a small portion of the anterior surface. 
The Inferior Extremity (extremitas inferior) (Figs. 1004 and 1005).-The inferior 
extremity, directed a little outward as well as downward, is smaller and thinner 
than the superior. It extends to within two inches of the crest of the ilium. 
At the hilum of the kidney the relative position of the main structures passing 
into and out of the kidney is as follows: the vein is in front, the artery in the 
middle, and the duct or ureter behind and toward the lower part (Fig. 1005). By 
a knowledge of these relations the student may distinguish between the right and 
left kidney. The kidney is to be laid on the table before the student on its 
posterior surface, with its lower extremity toward the observer-that is to say, 
with the ureter behind and below the other vessels; the hilum will then be directed 
to the side to which the kidney belongs. 
General Structure of the Kidney.-The kidney is surrounded by a distinct 
investment of fibrous tissue (tunica fibrosa), which forms the firm, smooth, true 
capsule covering the entire organ. The capsule passes over the margins of the 
hilum, enters the interior of the kidney, and covers the wall of the sinus. The 
true capsule is closely and firmly adherent to the renal pelvis where it is attached 
to the sinus. It closely invests it, but can be easily stripped off, in doing which, 
however, numerous fine processes of connective tissue which pass to the intrarenal 
connective tissue and numerous small blood-vessels are torn through. Beneath 
this fibrous layer a thin wide-meshed network of unstriped muscular fibre forms 
an incomplete covering to the organ. When the true capsule is stripped off, the 
surface of the kidney is found to be smooth, even, and of a deep-red color. 
In infants fissures extending for some depth may be seen on the surface of the 
organ, a remnant of the lobular construction of the gland (Fig. 1027). The kid- 
ney is dense in texture, but is easily lacerable by mechanical force. In order to 
obtain a knowledge of the structure of the gland, a vertical section must be made 
from its convex to its concave border, and the loose tissue and fat removed 
around the vessels and the excretory duct (Fig. 1010). It will be then seen that 
the kidney consists of a central cavity surrounded at all parts but one by the 
proper kidney-substance. This central cavity is called the sinus (sinus renalis), 
and is lined by a prolongation of the fibrous coat of the kidney, which enters 
through a longitudinal fissure, the hilum (hilus renalis) (Fig. 1010), which is 
situated at that part of the cavity which is not surrounded by kidney structure. 
Through this fissure the blood-vessels of the kidney and its excretory duct pass, 
and therefore these structures, upon entering the kidney, are contained within the 
sinus (Fig. 1004). The excretory duct or ureter, after entering, dilates into a wide, 
funnel-shaped sac named the pelvis (pelvis renalis) (Figs. 1010 and 1011). This 
divides into two or three tubular divisions, which subdivide into several short, 1416 
THE URINARY ORGANS 
truncated branches named calices or infundibula (calyces renales}, all of which 
are contained in the central cavity of the kidney (Figs. 1010 and 1011). The 
blood-vessels of the kidney, after passing through the hilum, are contained in 
the sinus or central cavity, lying between its lining membrane and the excretory 
apparatus, before entering the kidney-substance (Fig. 1011). 
This central cavity, as before mentioned, is surrounded on all sides except at 
the hilum by the substance of the kidney, which is at once seen to consist of two 
parts-viz., of an external granular investing part, which is called the cortical 
portion (substantia corticalis}; and of an internal part, the medullary portion (sub- 
stantia medullaris}, made up of a number of dark-colored pyramids, with their 
bases resting on the cortical part and their apices converging toward the centre, 
where they form prominent papillae, the renal papillae (papillae renales}, which 
project into the interior of the calices (Fig. 1010). 
SUPERIOR 
EXTREMITY 
MAJOR 
/CALICES 
RENAL 
rSINUS 
CUT SURFACE 
OF KIDNEY 
HILUM OF. 
KIDNEY 
MINOR 
CALICES 
I N FERIOR 
EXTREMITY 
Fig. 1010.-Vertical section of kidney. 
Fig. 1011.-The right kidney with its pelvis exposed, viewed 
from behind. (Spalteholz.) 
The cortical substance (Figs. 1010 and 1017) is of a bright reddish-brown color, 
soft, granular, and easily lacerable. It is found everywhere immediately beneath 
the capsule, and is seen to extend in an arched form over the base of each medul- 
lary pyramid. Prolongations of the cortical substance pass between the pyramids 
toward the renal sinus. These prolongations are the cortical columns or the columns 
of Bertin (columnae renales} (Fig. 1010, B B}. The columns contain blood-vessels, 
nerves, and lymphatics. The base of each pyramid (basis pyramidis} is known 
as the intermediate zone. That portion of the cortical substance which stretches 
from one cortical column to the next, and intervenes between the base of the 
pyramid and the capsule (marked by the dotted line extending from A to A' in Fig. 
1010), is called a cortical arch, the depth of which varies from a third to half an inch. 
The medullary substance (Figs. 1010 and 1017), as before stated, is seen to con- 
sist of red-colored, striated, conical masses, the pyramids of Malpighi (pyramides THE KIDNEYS 
1417 
renales) (rig. 1010), the number of which, varying from eight to eighteen, corre- 
sponds to the number of lobes of which the organ in the foetal state is composed. 
The pyramids are composed of straight tubes which pass between the apices of 
the papillae and the cortical margin. They enter the cortex in masses called the 
pyramids of Ferrein (see below). The sides of the pyramids of Malpighi are con- 
tiguous with the cortical columns, while the apices, known as the papillae of the 
kidney (papillae renales) (Figs. 1010 and 1014), project into the calices of the 
ureter, each calyx receiving two or three papillae. Radiating from the bases of 
the pyramids of Malpighi are ridges of cortical substance with distinct depres- 
sions between them. These ridges are the medullary rays (pars radiata) or pyra- 
mids of Ferrein (Figs. 1013 and 1017). The labyrinth of the cortex (Fig. 1013) is 
constituted by the kidney substance between the rays. The pyramids of Ftrrein 
look like direct continuations of the medullary sub- 
stance, but, in reality, they are in the cortex, and are 
formed by the straight tubes extending in masses into 
the cortex. The pyramids of Ferrein are much smaller 
than the pyramids of Malpighi. In the columns of 
Bertin blood-vessels, nerves, and lymphatics pass to and 
emerge from the sinus by way of small foramina. The 
summit of a papilla contains a number of orifices of 
papillary ducts. Such an area is called an area cribrosa 
(Fig. 1614). 
These two parts, cortical and medullary, so dissimilar 
in appearance, are very similar in structure, being 
made up of urinary tubes and blood-vessels united and 
bound together by a connecting matrix or stroma. 
Minute Anatomy.-The uriniferous tubes, urinary canals 
or tubuli uriniferi (tubuli renales) (Figs. 1012 and 1017), 
of which the kidney is for the most part made up, 
commence in the cortical portion of the kidney. Each 
tubule begins between the medullary rays (Fig. 1013) 
in a sac, Bowman's capsule or the Malpighian capsule 
(see below). The tubules, as a rule, after pursuing 
a very circuitous course through the cortical and medul- 
lary parts of the kidney, finally terminate at the apices 
of the Malpighian pyramids by open mouths, so that 
the fluid which they contain is emptied into the 
dilated extremity of the ureter contained in the sinus 
of the kidney. If the surface of one of the papillae 
is examined with a lens, it will be seen to be studded 
over with a number of small depressions (foramina 
papillaria), from sixteen to twenty in number, and in 
a fresh kidney, upon pressure being made, fluid will 
be seen to exude from these depressions. They are the orifices of the tubuli 
uriniferi, which terminate in this situation. The tubuli uriniferi begin in the cortex 
as the Malpighian bodies or corpuscles (corpuscula renis) (Figs. 1012, 1013, 1015, 
1016, and 1018), which are small rounded masses, varying in size, but average 
about of an inch in diameter. They are of a deep-red color, and are found 
only in the cortical portion of the kidney. Each of these little bodies is composed 
of two parts-a central glomerulus of vessels, called a Malpighian tuft, and a mem- 
branous envelope, the Malpighian capsule or capsule of Bowman (capsula glomeruli), 
which latter is a small pouch-like commencement of a uriniferous tubule. 
The Malpighian Tuft or Vascular Glomerulus (Figs. 1015, 1016, 1017, 1022, and 
1023) is a network of convoluted capillary blood-vessels held together by scanty 
Fig. 1012.-Plan of uriniferous 
tubes. A A, Malpighian bodies ; 
B B, margin of medullary struc- 
ture ; C, C, C, loops of Henle ; 
D, D, D, straight tubes cut off ; 
E, commencing straight tubes ; 
F, termination of straight tube or 
the excretory tube. THE URINA RY OR GA NS 
1418 
connective tissue and grouped into from two to five lobules. This capillary net- 
work is derived from a small arterial twig, the afferent vessel, which pierces the wall 
of the capsule, generally at a point opposite that at which the latter is connected 
with the tube; and the resulting efferent vessel emerges from the capsule at the same 
TUN ICA 
AI.BUGI N EA 
CONVOLUTED 
TUBULES 
MALPIGHIAN 
'corpuscles 
LABYRINTH 
OF CORTEX 
INTERLOBULAR 
ARTERY 
MEDULLARY 
RAYS 
CORTEX 
INTERLOBULAR 
VEIN 
VENOUS 
ARCH 
MEDULLA 
STRAIGHT 
TUBULES 
Fig. 1013.-Part of a section through the cortex of the kidney in the direction of the straight tubules. (Toldt.) 
point. The afferent vessel is usually the larger of the two (Fig. 1015). The Mal- 
pighian or Bowman's capsule (capsula glomeruli) (Figs.1015,1016, and 1017), which 
surrounds the glomerulus, is formed of a hyaline membrane supported by a small 
amount of connective tissue which is continuous with the connective tissue of the 
tube. It is lined on its inner surface 
with a layer of squamous epithelial 
cells which are reflected from the 
lining membrane on to the glomerulus 
at the point of entrance or exit of the 
afferent and efferent vessels. The 
whole surface of the glomerulus is 
covered with a continuous layer of 
the same cells on a delicate support- 
ing membrane, which with the cells 
dips in between the lobules of the 
glomerulus, closely surrounding them 
(Fig. 1016). Thus, between the 
glomerulus and the capsule a space 
is left, forming a cavity lined by a 
continuous layer of cells, which 
varies in size according to the state 
of secretion and the amount of fluid 
present in it. The cells, as above 
stated, are squamous in the adult, 
but in the foetus and young subject they are polyhedral or even columnar. 
The Tubuli Uriniferi, commencing in the Malpighian bodies, in their course 
present many changes in shape and direction (tubuli renales contorti), and are 
AREA CRIBROSA 
EXCRETORY 
TUBULES 
WALL OF RENAL CALYX 
Fig. 1014.-Area cribrosa of renal papilla. (Toldt.) THE KIDNEYS 
1419 
contained partly in the medullary and partly in the cortical portions of the organ. 
At the junction of a tubule with the Malpighian capsule there is a somewhat 
constricted portion which is termed the neck (Fig. 1018). Beyond this the tubule 
becomes convoluted, and pursues a considerable course in the cortical structure, 
constituting the proximal or first convoluted tubule (Figs. 1017 and 1018). After a 
time the convolutions disappear, and the tubule approaches the medullary portion 
of the kidney in a more or less spiral manner. This section of the tubule has 
been called the spiral tube of Schachowa (Fig. 1018). Throughout this portion 
of their course the tubuli uriniferi have been contained entirely in the cortical 
structure, and have presented a pretty uniform calibre. They now enter the 
medullary portion, and suddenly become much smaller, quite straight in direc- 
tion (tubuli renales recti), and each tubule dips down for a variable depth into 
the pyramids, constituting the descending limb of Henle's loop (Figs. 1017 and 
1018). Bending on itself, it forms a kind of loop near the apex of the pyramid, 
the loop of Henle, and, reascending, becomes suddenly enlarged and again spiral 
in direction, forming the ascending limb of Henle's loop (Figs. 1017 and 1018), 
Bowman's 
capsule. 
Vascular 
glomerulus. 
Fig. 1015.-Minute structure of kidney. 
Fig. 1016.-Malpighian body. 
and re-enters the cortical structure. This portion of the tubule does not present 
a uniform calibre, but becomes narrower as it ascends and irregular or somewhat 
spiral in outline (Fig. 1018). As a narrow tube it enters the cortex and ascends 
for a short distance, when it again becomes dilated, irregular, and angular. This 
section is termed the irregular tubule (Fig. 1018); it terminates in a convoluted 
tubule which exactly resembles the proximal convoluted tubule; and is called the 
distal or second convoluted tubule (Figs. 1017 and 1018). This again terminates 
in a narrow curved or junctional tubule, which enters the straight or collecting 
tube. 
Each straight collecting or receiving tube (Figs. 1012, 1017, and 1018) com- 
mences by a small orifice on the summit of a papilla, thus opening and discharg- 
ing its contents into the interior of one of the calices. Traced into the substance 
of the pyramid, these tubes are found to run from apex to base, dividing 
dichotomously in their course and slightly diverging from each other. Thus 
dividing and subdividing, they reach the base of the pyramid, and enter the 
cortical structure greatly increased in number. Upon entering the cortical por- 
tion they continue a straight course for a variable distance, and are arranged in 
groups, several of these groups corresponding to a single pyramid. The tubes in 
the centre of the group are the longest, and reach almost to die surface of the kid- 
ney, while the external ones are shorter, and advance only a short distance into 
the cortex. In consequence of this arrangement the cortical portion presents a 
number of conical masses, the apices of which reach the periphery of the organ, THE URINARY ORGANS 
1420 
and the bases are applied to the medullary portion. These are termed the medul- 
lary rays or the pyramids of Ferrein (Fig. 1013; also p. 1417). As they run through 
the cortical portion the straight tubes receive on either side the curved extremity 
of the convoluted tubes, which, as stated above, commence at the Malpighian 
bodies. Each collecting tube receives a number of tubules, and several collecting 
tubes unite together to form a papillary duct (Fig. 1017) and open by a foramen 
(Fig. 1014) at the surface of the papilla. 
Cortex 
Medullary 
ray 
Arteria 
Vena 
interlob- 
ular is 
■Arteria 
■ Vena 
Vena 
Arteria 
interlob- 
ularis 
Medulla 
Fig. 1017.-Diagrammatic representation of the course of the urinary canals (left) and the kidney vessels 
(right). The arteries are red, the veins blue; capsules of Bowman, convoluted tubules I. order and loops of 
Henle are black; convoluted tubules II. order and collecting tubules gray. I.. IL, III., IV., four kidney 
lobules: a, vas afferens; e, vas efferens. 1, Bowman's capsule; 2, convoluted tubule I. order; 3, descending 
limb of loop of Henle; 4, ascending limb of loop of Henle; 5, convoluted tubule II. order; 6, 7, collecting 
tubules; 8, papillary duct. (Szymonowicz.) 
It will be seen from the above description that there is a continuous series 
of tubes from their commencement in the Malpighian bodies to their termina- 
tion at the orifices on the apices of the pyramids of Malpighi, and that the urine, THE KIDNEYS 
1421 
the secretion of which commences in the capsule, finds its way through these 
tubes into the calices of the kidney, and so into the ureter. To recapitulate: 
the tube first presents a con- 
stricted portion, (1) the neck. 
2. It forms a wide convoluted 
tube, the proximal convoluted 
tube. 3. It becomes spiral, the 
spiral tubule of Schachowa. 4. It 
enters the medullary structure 
as a narrow, straight tube, the 
descending limb of Henle's loop. 
5. Forming a loop and becom- 
ing dilated, it ascends somewhat 
spirally, and, gradually dimin- 
ishing in calibre, again enters 
the cortical structure, the as- 
cending limb of Henle's loop. 
6. It now becomes irregular 
and angular in outline, the 
irregular tubule. 7. It then be- 
comes convoluted, the distal 
convoluted tubule. 8. Diminish- 
ing in size, it forms a curve, the 
curved or junctional tubule. 9. 
Finally, it joins a straight tube, 
the straight collecting tube,which 
is continued downward through 
the medullary substance and 
joins other straight tubes to 
form a papillary duct, which 
opens in a foramen at the apex 
of a pyramid. 
Distal 
convo- 
luted 
tubule. 
Junctional 
tubule. 
Malphigian 
body. 
Neck. 
Proximal 
convoluted 
tubule.. 
Irregular 
tubule. 
Spiral tubule of 
Schachowa. 
Spiral part 
of ascending 
limb. 
Straight 
collecting 
tube. 
Ascending 
limb. 
Descending limb 
of Henle's loop. 
Fig. 1018.-Uriniferous tube. For the sake of clearness the 
epithelial cells have been represented more highly magnified than 
the tubes in which they are contained. 
Fig. 1019.1-Longitu- Fig. 1020.-Longitu- 
dinal section of Henle's dinal section of straight 
descending limb: a, tube: a, cylindrical or 
membrana propria ; b, cubical epithelium ; b, 
epithelium. membrana propria. 
Fig. 1021.-Transverse section of pyramidal substance of 
kidney of pig, the blood-vessels of which are injected: a, large 
collecting tube cut across, lined with cylindrical epithelium ; 
b, branch of collecting tube cut across, lined with epithelium 
with shorter cylinders; c and d. Henle's loops cut across ; e, 
blood-vessels cut across ; D, connective-tissue ground-sub- 
stance. 
The Tubuli Uriniferi: their Structure (Figs. 1019, 1020, and 1021.- 
ihe tubuli uriniferi consist of basement-membrane lined with epithelium. The 
1 From Handbook for the Physiological Laboratory. 1422 
THE URINARY ORGANS 
epithelium vanes considerably in different sections ot the uriniferous tubes. In 
the neck the epithelium is continuous with that lining the Malpighian capsule, 
and, like it, consists of flattened cells with an oval nucleus (Fig. 1016). The cells 
are, however, very indistinct and difficult to trace, and the tube has here the 
appearance of a simple basement-membrane unlined with epithelium. In the 
proximal convoluted tubule and the spiral tubule of Schachowa the epithelium is 
polyhedral in shape, the sides of the cells not being straight, but fitting into 
each other, and in some animals so fused together that it is impossible to make 
out the lines of junction. In the human kidney the cells often present an angular 
projection of the surface next the basement-membrane. These cells are made 
up of more or less rod-like fibres, which rest by one extremity on the basement- 
membrane, whilst the other projects toward the lumen of the tube. This gives 
to the cells the appearance of distinct striation. In the descending limb of Henle's 
loop the epithelium resembles that found in the Malpighian capsule and the 
commencement of the tube, consisting of flat transparent epithelial plates with 
an oval nucleus (Fig. 1019). In the ascending limb, on the other hand, the 
cells partake more of the character of those described as existing in the prox- 
imal convoluted tubule, being polyhedral in shape and presenting the same 
appearance of striation. The 
nucleus, however, is not situ- 
ated in the centre of the cell, 
but near the lumen (Fig. 
1021). After the ascending 
limb of Henle's loop becomes 
narrower upon entering the 
cortical structure, the stria- 
tion appears to be confined 
to the outer part of the cell; 
at all events, it is much more 
distinct in this situation, the 
nucleus, which appears flat- 
tened and angular, being still 
situated near the lumen. In 
the irregular tubule the cells 
undergo a still further change, 
becoming very angular, and 
presenting thick bright rods 
or markings, which render the 
striation much more distinct 
than in any other section of 
the urinary tubules. In the 
distal convoluted tubule the 
epithelium appears to be 
somewhat similar to that 
which has been described as 
existing in the proximal convoluted tubule, but presents a peculiar refractive 
appearance. In the curved tubule, just before its entrance into the straight 
collecting tube, the epithelium varies greatly as regards the shape of the cells, 
some being angular with short processes, others spindle-shaped, others poly- 
hedral. 
In the straight tubes the epithelium is more or less columnar; in its papillary 
portion the cells are distinctly columnar and transparent (Fig. 1020), but as the 
tube approaches the cortex the cells are less uniform in shape; some are poly- 
hedral, and others angular with short processes. 
Fig. 1022.-Diagrammatic 
sketch of the blood-vessels of 
the kidney. 
Fig. 1023.-A portion of Fig. 1022 
enlarged. (The references are the 
same.) 
a, a, interlobar artery and vein, the former giving off the renal 
afferents, the latter receiving the renal efferents ; b, 6, interlobular 
artery and vein, the latter commencing from the stellate veins, and 
receiving branches from the plexus around the tubuli contorti, the 
former giving off renal afferents ; c, straight tube, surrounded by 
tubuli contorti, with which it communicates, as more fully shown in 
Fig. 1023 ; d, margin of medullary substance ; e, e, e, receiving tubes 
cut off; f, f, arteriolae et venae rectae, the latter arising from (g) the 
plexus at the medullary apex; x, vascular glomerulus; w, the arcuate 
artery and vein. THE KIDNEYS 
1423 
The Renal Blood-vessels.-The kidney is plentifully supplied with blood by 
the renal artery (Figs. 422, 423, 1005, and 1011), a large offset of the abdominal 
aorta. Previously to entering the kidney, each artery divides into four or five 
branches, which are distributed to its substance. At the hilum these branches 
lie between the renal vein and ureter, the vein being in front, the ureter behind. 
Each vessel gives off a small branch to the suprarenal capsules, the ureter, and 
the surrounding cellular tissue and muscles. It has been pointed out by Hyrtl 
(p. 679) that the renal artery gives off a branch which divides and supplies the 
dorsal portion of the kidney and a branch which divides and supplies the ventral 
portion of the kidney (Figs. 422 and 423). Between these two vascular systems 
is a non-vascular zone, called by Byron Robinson the exsanguinated renal 
zone of Hyrtl (Figs. 422 and 423). It "is one-half inch dorsal to the lateral 
longitudinal renal border."1 Frequently there is a second renal artery, which is 
given off from the abdominal aorta at a lower level, and supplies the lower por- 
tion of the kidney. It is termed the inferior renal artery. The branches of the 
renal arteries pass to the kidney substance between the pyramids and are 
known as interlobar arteries (arteriae interlobares rents) (Figs. 1013, 1017, 1024, 
and 1025). At the junction of the cortical and medullary portions these vessels 
turn and for a short distance pursue a course parallel to the kidney surface. 
There are thus formed a series of incomplete vascular arches across the bases 
of the pyramids, the arcuate arteries (arteriae arcijorvies) (Figs. 1017, 1022, and 
1023). From these arches two sets of vessels come. The vessels of one set go 
to the periphery and enter the labyrinth, those of the other set pass toward the 
centre and enter the intermediate zone of the medulla. These last vessels are 
the arteriolae recti (Figs. 1017, 1022, and 1023). 
Because of these vessels the kidney exhibits stria- 
tions on section. Each of the arteriolae recti 
in the medulla divides into numerous small 
branches which are nearly parallel to each other 
Fig. 1026.-Diagrammatic representation 
of the blood-vessels in the substance of the 
cortex of the kidney: m, region of the 
medullary ray ; b, region of the tortuous 
portion of the tubules; ai, interlobular 
artery; it, interlobular vein; ia, vas affer- 
ens ; gl, glomerulus ; re, vas efferens ; vz, 
venous twig of the interlobularis. (From 
Ludwig, in Stricker's Handbook.) 
Figs. 1024 and 1025.-Lobar circulation. Interlobar 
circulation. (Poirier and Charpy.) 
and supply the tubules of this region. The arteries which arise from the arches 
and pass to the periphery are the interlobular arteries (arteriae interlobular es) 
(Figs. 1017, 1022, 1023, and 1026). They traverse the labyrinth and pass toward 
the surface of the kidney. A number of short branches, the vasa afferentia, are 
given off by the interlobular arteries (Figs. 1017, 1022, 1023, and 1026). Each 
afferent vessel passes to a capsule of Bowman. On reaching the capsule the 
vessel forms a capillarv mass, the glomerulus, which is within the invaginatcd 
capsule (Figs. 1016, 1017, 1023, and 1026). 
1 Byron Robinson, p. 679. THE URINARY ORGANS 
1424 
Emerging from each glomerulus is a small vessel, the vas efferens (rigs. 1015, 
1016, 1017, 1023, and 1026). This vessel divides into capillaries which are dis- 
tributed to the tubules of the labyrinth and medullary rays. Blood is gathered 
from the capillaries about the tubules by veins which correspond to the inter- 
lobular arteries and arteriolae recti. These veins form a set of arches across 
the bases of the pyramids. From the arches veins aiise and pass between the 
pyramids to the sinus of the kidney, where they unite and form branches of 
the renal vein. 
Nerves of the Kidney.-The nerves of the kidney, although small, are about 
fifteen in number. They have small ganglia developed upon them, and are derived 
from the renal plexus, which is formed by branches from the solar plexus, the 
lower and outer part of the semilunar ganglion and aortic plexus, and from the 
lesser and smallest splanchnic nerves. They communicate with the spermatic 
plexus, a circumstance which may explain the occurrence of pain in the testicle in 
affections of the kidney. So far as they have been traced, they seem to accompany 
the renal artery and its branches, but their exact mode of termination is not 
known. 
The Lymphatics.-The lymphatics consist of a superficial and deep set. 
The superficial lymphatics are just beneath the capsule. From them come two 
sets of collecting trunks (Sappey). One set joins the deep collectors by entering 
the kidney substance or passing to the hilum. Another 
set pass into the lymphatics of the fatty capsule. 
The deep collectors emerge from the hilum and lie 
about the renal artery and vein. From the right kidney 
some of the trunks pass to the glands about the vena 
cava and possibly also in the glands in front of the 
aorta. Others end in the glands back of the vena cava 
(Stahr). 
From the left kidney the trunks pass to the glands 
which lie along the left side of the abdominal aorta.1 
The lymphatics of the fatty capsule of the kidney pass 
to the same glands as do the deep collectors of the 
kidney (Stahr). 
Connective Tissue or Intertubular Stroma.-Although 
the tubules and vessels are closely packed, a certain 
small amount of connective tissue, continuous with the 
capsule, binds them firmly together. This tissue was 
first described by Goodsir, and subsequently by Bow- 
man. Ludwig and Zawarykin have observed distinct fibres passing around the 
Malpighian bodies, and Henle has seen them between the straight tubes com- 
posing the medullary structure. 
Variations and Abnormalities.-Congenital absence of the kidney has been 
observed. Not unusually one kidney is considerably larger than the other; occa- 
sionally one is very large and the other is very small, from atrophy, the large 
organ having become large in response to a functional need, which causes it to 
compensate for the insufficiency of the small kidney. If a kidney is removed 
surgically, the other kidney enlarges. As previously stated, the kidneys of the 
foetus and of the young child show distinct fissures which makes each organ 
lobulated (Fig. 1027). The adult kidneys frequently exhibit remains of these 
fissures. A horseshoe kidney is a condition in which the lower poles of the two 
kidneys are united by kidney structure, the bond of union crossing the middle line. 
The strip of kidney tissue which effects the junction may be slight in amount, 
FiG.io27.obFoetai kidney^ showing 
1 The Lymphatics. By Poirier, Cun6o, and Delamare. Translated and edited by Cecil H. Leaf. THE KIDNEYS 
1425 
considerable, or extensive. Sometimes the two kidneys are completely fused 
together into one large organ with two ureters. 
Surface Form. - The kidneys, being situated at the back part of the abdominal cavity and 
deeply placed, cannot be felt unless enlarged or misplaced. They are situated on the confines 
of the epigastric and umbilical regions internally, with the hypochondriac and lumbar regions 
externally. The left is somewhat higher than the right. According to Morris, the position of 
the kidney may be thus defined: Anteriorly: "1. A horizontal line through the umbilicus is 
below the lower edge of each kidney. 2. A vertical line carried upward to the costal arch from 
the middle of Poupart's ligament has one-third of the kidney to its outer side and two-thirds to 
its inner side-i. e., between this line and the median line of the body." In adopting these lines 
it must be borne in mind that the axes of the kidneys are not vertical, but oblique, and if con- 
tinued upward would meet about the ninth dorsal vertebra. Posteriorly: The upper end of the 
left kidney would be defined by a line drawn horizontally outward from the spinous process of the 
eleventh dorsal vertebra, and its lower end by a point two inches above the iliac crest. The right 
kidney would be half to three-quarters of an inch below. Morris lays down the following rules 
for indicating the position of the kidney on the posterior surface of the body: "1. A line parallel 
with, and one inch from, the spine, between the lower edge of the tip of the spinous process 
of the eleventh dorsal vertebra and the lower edge of the spinous process of the third lumbar 
vertebra. 2. A line from the top of this first line outward at right angles to it for two and three- 
quarter inches. 3. A line from the lower end of the first transversely outward for two and three- 
quarter inches. 4. A line parallel to the first and connecting the outer extremities of the second 
and third lines just described." 
The hilum of the kidney lies about two inches from the middle line of the back, at the level 
of the spinous process of the first lumbar vertebra. 
Surgical Anatomy.-Cases of congenital absence of a kidney, of atrophy of a kidney, and 
of horseshoe kidney are of great importance, and must be duly taken into account, when neph- 
rectomy is contemplated. A more common malformation is where the two kidneys are fused 
together. They may be only joined together at their lower ends by means of a thick mass of 
renal tissue, so as to form a horseshoe-shaped body, or they may be completely united, forming 
a disk-like kidney, from which two ureters descend into the bladder. These fused kidneys are 
generally situated in the middle line of the abdomen, but may be misplaced as well. 
One or both kidneys may be misplaced as a congenital condition, and remain fixed in this 
abnormal position. They are then very often misshapen. They may be situated higher or lower 
than normal or removed farther from the spine than usual or they may be displaced into the 
iliac fossa, over the sacro-iliac joint, on to the promontory of the sacrum, or into the pelvis 
between the rectum and bladder or by the side of the uterus. In these latter cases they may 
give rise to very serious trouble. The kidney may also be misplaced as a congenital condition, 
but may not be fixed. It is then known as a floating kidney. It is believed to be due to the 
fact that the kidney is completely enveloped by peritoneum, which then passes backward to the 
spine as a double layer, forming a mesonephron, which permits of movement taking place. The 
kidney may also be misplaced as an acquired condition; in these cases the kidney is mobile in 
the tissues by which it is surrounded, either moving in or moving with its fatty capsule. This 
condition is known as movable kidney (nephroptosis'), and is more common in the female than 
in the male, and on the right than the left side. If a displaced kidney becomes fixed in an 
abnormal position, it is said to be dislocated. Movable kidney cannot be distinguished from 
floating kidney until the kidney is exposed by incision. Other malformations are the persist- 
ence of the foetal lobulation; the presence of two pelves or two ureters to the one kidney. In 
some rare instances a third kidney may be present. 
The kidney is embedded in a large quantity of loose fatty tissue, and is but partially covered 
by peritoneum; hence, rupture of this organ is not nearly so serious an accident as rupture of 
the liver or spleen, since the extravasation of blood and urine which follows is, in the majority 
of cases, outside the peritoneal cavity. Occasionally the kidney may be bruised by blows in the 
loin or by being compressed between the lower ribs and the ilium when the body is violently 
bent forward. This is followed by a little transient hamaturia, which, however, speedily passes 
off. Occasionally, when rupture involves the pelvis of the kidney or the commencement of the 
ureter, this duct may become blocked, and hydronephrosis follows. 
The loose cellular tissue around the kidney may be the seat of suppuration, constituting 
perinephritic abscess. This may be due to injury, to disease of the kidney itself, or to extension 
of inflammation from neighboring parts. The abscess may burst into the pleura, causing 
empyema; into the colon or bladder; or may point externally in the groin or loin. Tumors of the 
kidney, of which, perhaps, sarcoma in children is the most common, may be recognized by their 
position and fixity; by the resonant colon lying in front of it; by their not moving with respira- 
tion; and by their rounded outline, not presenting a notched anterior margin like the spleen, with 
which they are most likely to be confounded. The examination of the kidney should be bimanual; 
that is to say, one hand should be placed in the flank and firm pressure made forward, while 1426 
THE URINARY ORGANS 
the other hand is buried in the abdominal wall, over the situation of the organ. Manipulation 
of the kidney frequently produces a peculiar sickening sensation and some faintness. 
The kidney has, of late years, been frequently attacked surgically. It may be exposed and 
opened for exploration or the evacuation of pus (nephrotomy); it may be incised for the removal 
of stone (nephrolithotomy); it may be sutured when wounded (nephrorrhaphy); it may be fixed 
in place by sutures (nephropexy) or gauze pads when movable or floating; or it may be removed 
(nephrectomy). 
The kidney may be exposed either by a lumbar or abdominal incision. The operation is 
best performed by a lumbar incision, except in a case of very large tumor or of wandering kid- 
ney with a loose mesonephron, on account of the advantages which it possesses of not opening 
the peritoneum and of affording admirable drainage. It may be performed either by an oblique 
a vertical, or a transverse incision. A common incision for exposing the kidney begins an inch 
below the twelfth rib at the margin of the Erector spinae muscle and passes obliquely down- 
ward and forward, exposing the anterior border of the Latissimus dorsi and the posterior border 
of the Internal oblique. The surgeon divides the posterior leaflet of the lumbar fascia, draws aside 
or incises the Quadratus lumborum, and cuts the anterior leaflet of the lumbar fascia and also the 
transversalis fascia. He opens the fatty capsule down to the kidney and strips it from the true 
capsule, bringing the kidney outside of the body for inspection. The vertical incision at the 
edge of the Erector spinae muscle is frequently used. A gridiron or muscle-splitting operation 
is used by some in order to avoid the division of nerves, vessels, and muscular fibre. 
The abdominal operation is best performed by an incision in the linea semilunaris on the 
side of the kidney to be removed, as recommended by Langenbuch; the kidney is then reached 
from the outer side of the colon, ascending or descending, as the case may be, and the vessels 
of the colon are not interfered with. If the incision were made in the linea alba, the kidney 
would be reached from the inner side of the colon, and the vessels running to supply the colon 
would necessarily be interfered w'ith. The incision is made of varying length according to the 
size of the kidney, and commences just below the costal arch. The abdominal cavity is opened. 
The intestines are held aside, and the outer layer of the mesocolon incised, so that the fingers 
can be introduced behind the peritoneum and the renal vessels are sought for. These vessels 
are then to be ligatured: if tied separately, care must be taken to ligature the artery first. The 
kidney must now' be enucleated, and the vessels and the ureter divided, and the latter disinfected 
and tied, and, if it is thought necessary, stitched to the edge of the wound. 
THE URETER (Figs. 1004, 1005, 1006, 1011, 1028, 1029). 
The ureters are the two tubes which conduct the urine from the kidneys into 
the bladder. fhe ureter commences within the sinus of the kidney by a number 
of short truncated branches, the calices or infundibula, which unite either directly 
or indirectly to form a dilated pouch, the pelvis (Fig. 1010), from which the ureter, 
after passing through the hilum of the kidney, descends to the bladder. The calices 
are cup-like tubes encircling the apices of the Malpighian pyramids; but inasmuch 
as one calyx may include two or even more papillae, their number is generally 
less than the pyramids themselves. The calices vary in number from eight to 
eighteen. These calices converge into two or three tubular divisions which by 
their junction form the pelvis or dilated portion of the ureter. The portion last 
mentioned, where the pelvis merges into the ureter proper, is found opposite 
the spinous process of the first lumbar vertebra, in which situation it is accessible 
behind the peritoneum (Fig. 1006). 
The Ureter Proper.-The ureter proper is a cylindrical membranous tube, 
about sixteen inches in length and of the diameter of a goosequill, extending from 
the pelvis of the kidney to the bladder. Its course is obliquely downward and 
inward through the lumbar region (pars abdominalis) (Fig. 1029), into the cavity of 
the pelvis (pars pelvina)(Fig. 1029),where it passes downward, forward,and inward 
across that cavity to the base of the bladder, into which it then opens by a con- 
stricted orifice (orificium ureteris) (Fig. 1045), after having passed obliquely for 
nearly an inch between its muscular and mucous coats (Fig. 1028). The lower 
part of the abdominal portion of the ureter exhibits a spindle-shaped dilatation. 
Relations (Fig. 1029).-In its course it rests upon the Psoas muscle, being 
covered by the peritoneum, and crossed obliquely, from within outward, by the THE URETER 
1427 
spermatic vessels; the right ureter is crossed by the branches of the mesenteric 
arteries, which are distributed to the ascending colon, and the left ureter by those 
for the descending colon; the right ureter lying close to the outer side of the infe- 
rior vena cava. Opposite the first piece of the sacrum it crosses either the common 
or external iliac artery and vein, lying behind the 
ileum on the right side and behind the sigmoid 
flexure of the colon on the left side. In the pelvis 
it enters the posterior false ligament of the bladder, 
below the obliterated hypogastric artery, the vas 
deferens in the male passing between it and the 
bladder. In the female the ureter is to the inner 
side of the uterine artery at the wall of the pelvis, 
it passes forward and inward below the posterior 
layer of the broad ligament running through the 
parametrium, passing along the side of the neck 
of the uterus and upper part of the vagina, 
being in contact with the anterior and lateral 
vaginal walls and being crossed anteriorly by 
the uterine artery (Fig. 1099). At the base of the 
bladder the ureter is situated about two inches from its fellow: lying, in the male, 
about an inch and a half from the vesical orifice of the urethra, at one of the 
posterior angles of the trigone (Fig. 1045). 
Structure.-The ureter is composed of three coats-fibrous, muscular, and 
mucous. 
Fig. 1028.-Diagram showing method 
of entrance of the ureter into the blad- 
der. (F. H. Gerrish.) 
RIGHT URETER 
PSOAS MUSCLE 
ASCENDING 
COLON 
LEFT URETER 
I LEUM 
appendix (drawn 
up under) 
SUPERIOR 
HEMORRHOIDAL 
ARTERY 
ARTERIES OF 
SIGMOID^ 
FLEXURE 
ARTERY TO 
-SIGMOID 
FLEXURE 
SIGMOID 
COLON 
Fig. 1029.-The relations of the pelvic mesocolon with the wall, the iliac sigmoid and superior hemorrhoidal 
arteries and the ureter. (Poirier and Charpy.) 
The Fibrous Coat (tunica adventitia).-The fibrous coat is the same throughout 
the entire length of the duct, being continuous at one end with the fibrous capsule 
of the kidney at the floor of the sinus, while at the other it is lost in the fibrous 
structure of the bladder. 1428 
THE URINARY ORGANS 
The Muscular Coat (tunica muscularis).-In the pelvis of the kidney the mus- 
cular coat consists of two layers, longitudinal and circular: the longitudinal fibres 
become lost upon the sides of the papillae at the extremities of the calices; the 
circular fibres may be traced surrounding the medullary structure in the same 
situation. In the ureter proper the muscular fibres are very distinct, and are 
arranged in three layers-an external longitudinal (stratum externum), a middle 
circular (stratum medium), and an internal layer (stratum internum), less distinct 
than the other two, but having a general longitudinal direction. According to 
Kblliker, this internal layer is only found in the neighborhood of the bladder. 
The Mucous Coat (tunica mucosa).-The mucous coat is smooth, and presents a 
few longitudinal folds which become effaced by distention. It is continuous with 
the mucous membrane of the bladder below,whilst it is prolonged over the papillae 
of the kidney above. Its epithelium is of a peculiar character, and resembles that 
found in the bladder. It is known by the name of transitional epithelium. It con- 
sists of several layers of cells, of which the innermost-that is to say, the cells in 
contact with the urine-are quad rilateral in shape, with concave margins on their 
outer surface, into which fit the rounded ends of the cells of the second layer. 
These, the intermediate cells, more or less resemble columnar epithelium, and are 
pear-shaped, with a rounded internal extremity which fits into the concavity of 
the cells of the first layer, and a narrow external extremity which is wedged in 
between the cells of the third layer. The external or third layer consists of conical 
or oval cells varying in number in different parts, and presenting processes which 
extend down into the basement-membrane. 
Vessels and Nerves.-The arteries supplying the ureter are branches from the 
renal, spermatic, internal iliac, and inferior vesical. 
The nerves are derived from the inferior mesenteric, spermatic, and pelvic plexuses. 
Surgical Anatomy.-Subcutaneous rupture of the ureter is not a common accident, but occa- 
sionally occurs from a sharp, direct blow on the abdomen, as from the kick of a horse. The ureter 
may be either torn completely across, or only partially divided, and, as a rule, the peritoneum 
escapes injury. If torn completely across the urine collects in the retroperitoneal tissues; if it 
is not completely divided, the lumen of the tube may become obstructed and hydro-nephrosis or 
pyo-nephrosis results. The ureter may be accidentally wounded in some abdominal operations; 
if this should happen, the divided ends must be sutured together, or, failing to accomplish this, 
the upper end must be implanted into the bladder or the intestine. 
THE SUPRARENAL CAPSULE OR GLAND (GLANDULA 
SUPRARENALIS) (Figs. 1010, 1030, 1031). 
The suprarenal capsules belong to the class of ductless glands. They are two 
small flattened bodies, of a yellowish color, situated at the back part of the abdo- 
men, behind the peritoneum, and immediately above and in front of the upper 
end of each kidney; hence their name. The right one (Fig. 1030) is somewhat 
triangular in shape, bearing a resemblance to a cocked hat; the left (Fig. 1031) is 
more semilunar, usually larger and placed at a higher level than the right. They 
vary in size in different individuals, being sometimes so small as to be scarcely 
detected; their usual size is from an inch and a quarter to nearly two inches in 
length, rather less in width, and from two to three lines in thickness. Their 
average weight is from one to one and a half drachms each. 
Relations.-The relations of the suprarenal capsules (litter on the two sides of 
the body. 
The Right Suprarenal (Fig. 1030).-The right suprarenal is roughly triangular in 
shape, its angles pointing upward, downward, and outward. It presents two sur- 
faces for examination, an anterior and a posterior. The anterior surface (facies THE SUPRARENAL CAPSULE OR GLAND 
1429 
anterior) presents two areas, separated by a furrow, the hilum (hilus glandulae 
suprarenalis): one area occupying about one-third of the whole surface, is situ- 
ated above and internally; it is depressed, uncovered by peritoneum, and is in 
contact in front with the posterior surface of the right lobe of the liver, and along 
its inner border with, the inferior vena cava; the remaining area is elevated, and 
is divided into a non-peritoneal portion, in contact with the hepatic flexure of 
the duodenum, and a portion covered by peritoneum forming the hepato-renal 
fold. The posterior surface (facies posterior) is slightly convex, and rests upon 
the Diaphragm. The base (basis glandulae suprarenalis) is concave, and is in 
contact with the upper end and the adjacent part of the anterior surface of the 
kidney. 
The Left Suprarenal (Fig. 1031).-The left suprarenal is crescentic in shape, its 
concavity being adapted to the upper end of the left kidney. It presents an inner 
SUPRARENAL 
VEIN 
ANTERIOR 
surface' 
BASE. 
ANTERIOR 
SURFACE 
HILUM- 
HILUM 
SUPRARENAL 
ARTERY 
SUPRARENAL 
VEIN 
SUPRARENAL 
ARTERY 
Fig. 1030.-The right suprarenal gland. 
(Spalteholz.) 
Fig. 1031.-The left suprarenal gland. 
(Spalteholz.) 
border which is convex, and an outer which is concave; its upper border is narrow, 
and its lower rounded. Its anterior surface (facies anterior) presents two areas: an 
upper one, covered by the peritoneum forming the lesser sac, which separates it 
from the cardiac end of the stomach and to a small extent from the superior 
extremity of the spleen; and a lower one, which is in contact with the pancreas 
and splenic artery, and is therefore not covered by the peritoneum. A hilum is 
present, as in the right suprarenal. Its posterior surface (facies posterior) presents 
a vertical ridge, which divides it into two areas. The ridge lies in the sulcus 
between the kidney and crus of the Diaphragm, while the area on either side of 
it lies on these parts respectively; the outer area, which is thin, resting on the 
kidney, and the inner and smaller area resting on the left crus of the Diaphragm. 
The surface of the suprarenal gland is surrounded by areolar tissue containing 
much fat, and closely invested by a thin fibrous coat, which is difficult to remove, 
on account of numerous fibrous processes and vessels which enter the organ 
through the furrows on its anterior surface and base. 
Accessory Suprarenal Glands (glandulae suprarenales accessoriae).-Small 
accessory suprarenals are often to be found in the connective tissue around the 
suprarenals. The smaller of these, on section, show a uniform surface, but in 
some of the larger a distinct medulla can be made out. 
Structure (Figs. 1032, 1033, and 1034).-On making a perpendicular section 
(Fig. 1032), the suprarenal gland is seen to consist of two substances-external or 
cortical and internal or medullary. The former, which constitutes the chief part of 
the organ, is of a deep-yellow color. The medullary substance is soft, pulpy, 1430 
THE URINARY ORGANS 
and of a dark-brown or black color, whence the name atrabiliary capsules formerly 
given to these organs. In the centre is often seen a space, not natural, but 
formed by breaking down after death of the medullary substance. 
The Cortical Portion {substantia corticalis) (Fig. 1032).-The cortical substance 
consists chiefly of narrow columnar masses placed perpendicularly to the surface. 
This arrangement is due to the disposition of the capsule, which sends into the 
interior of the gland processes passing in vertically and communicating with each 
other by transverse bands so as to form spaces 
which open into each other. These spaces are 
of slight depth near the surface of the organ, 
so that there the section somewhat resembles a 
net; this is termed the zona glomerulosa; but 
they become much deeper or longer farther in, 
so as to resemble pipes or tubes placed endwise, 
.Connective 
tissue. 
Capsule. 
Zona 
glomerulosa. 
Zona 
fasciculata. 
Gland 
cylinders. 
Fig. 1033.- Minute structure of suprarenal 
capsule. 
Framework. 
Nuclei. 
Zona reticularis. 
Medulla. 
Capillary. 
Gland 
cells. 
Large 
vein. 
Fig. 1032.-Vertical section of the suprarenal capsule. (From 
Elberth, in Stricker's Manual.) 
Fig. 1034.-Minute structure of suprarenal 
capsule. 
the zona fasciculata. Still deeper down, near the medullary part, the spaces 
become again of small extent; this is named the zona reticularis. These processes 
or trabeculae, derived from the capside and forming the framework of the spaces, 
are composed of fibrous connective tissue with longitudinal bundles of unstriped 
muscular fibres. Within the interior of the spaces are contained groups of poly- 
hedral cells, which are finely granular in appearance, and contain a spherical 
nucleus, and not infrequently fat-globules. These groups of cells do not entirely 
fill the spaces in which they are contained, but between them and the trabeculae 
of the framework is a channel which is believed to be a lymph-path or sinus, 
and which communicates with certain passages between the cells composing the THE CAVITY OF THE PELVIS 
1431 
group. The lymph-path is supposed to open into a plexus of efferent lymphatic 
vessels which are contained in the capsule. 
The Medullary Portion (substantia medullaris) (Fig. 1032).-In the medullary 
portion the fibrous stroma seems to be collected together into a much closer 
arrangement, and forms bundles of connective tissue which are loosely applied 
to the large plexus of veins of which this part of the organ mainly consists. In 
the interstices lie a number of cells compared by Frey to those of columnar epithe- 
lium. They are coarsely granular, do not contain any fat-molecules, and some 
of them are branched. Luschka has affirmed that these branches are connected 
with the nerve-fibres of a very intricate plexus which is found in the medulla; this 
statement has not been verified by other observers, for the tissue of the medullary 
substance is less easy to make out than that of the cortical, owing to its rapid 
decomposition. 
Vessels and Nerves.-The numerous arteries which enter the suprarenal bodies 
from the sources mentioned below penetrate the cortical part of the gland, where 
they break up into capillaries in the fibrous septa, and these converge to the very 
numerous veins of the medullary portion, which are collected together into the 
suprarenal vein, which usually emerge as a single vessel from the centre of the 
gland. 
The arteries supplying the suprarenal capsules are three in number and of large 
size; they are derived from the aorta, the phrenic, and the renal; they subdivide 
into numerous minute branches previous to entering the substance of the gland. 
I'he suprarenal vein returns the blood from the medullary venous plexus, and 
receives several branches from the cortical substance; it emerges from the hilum 
and opens on the right side into the inferior vena cava, on the left side into the 
renal vein. 
The lymphatics form several collections which are about the beginning of the 
suprarenal vein. They terminate in the glands to the corresponding side of the 
aorta. 
The nerves are exceedingly numerous, and are derived from the solar and 
renal plexuses, and, according to Bergmann, from the phrenic and pneumogastric 
nerves. They enter the lower and inner part of the capsule, traverse the cortex, 
and terminate about the cells of the medulla. They have numerous small ganglia 
developed upon them, from which circumstance the organ has been conjectured 
to have some function in connection with the sympathetic nervous system. 
THE CAVITY OF THE PELVIS. 
The cavity of the pelvis is that part of the general abdominal cavity which is 
below the level of the ilio-pectineal lines and the promontory of the sacrum. 
Boundaries.-It is bounded behind by the sacrum, the coccyx, the Pyriformis 
muscles, and the great sacro-sciatic ligaments; in front and at the sides by the 
portions of the innominate bones below the ilio-pectineal lines. In front and 
to the sides the bony sides of the pelvic cavity are partly covered by the internal 
Obturator muscles, and internal to these muscles by the parietal part of the 
pelvic fascia. Above, it communicates with the cavity of the abdomen; and 
below, the outlet is closed by the triangular ligament, the Levatores ani and 
Coccygei muscles, and the visceral layer of the pelvic fascia, which is reflected 
from the wall of the pelvis on to the viscera. 
Contents.-The viscera contained in this cavity are-the urinary bladder, the 
rectum, and some of the generative organs peculiar to each sex, and some convo- 
lutions of the small intestines. The pelvic viscera are partially covered by the 
peritoneum, and supplied with blood-vessels, lymphatics, and nerves. 1432 
THE URINARY ORGANS 
THE URINARY BLADDER (VESICA URINARIA) (Figs. 1037, 1038, 1054, 1055). 
The urinary bladder is the reservoir for the urine. It is a musculo-membranous 
sac situated in the pelvis, behind the pubes, and in front of the rectum in the male, 
the cervix uteri and vagina intervening between it and that intestine in the female. 
The shape, position, and relations of the bladder are greatly influenced by age, 
Fig. 1035.-The empty bladder. (Poirier and Charpy.) 
Fig. 1036.-Modifications of form of the blad- 
der during distention (Poirier and Charpy.) 
Space of 
Retzius. 
Suspensory 
ligament 
SPHINCTER ANt. 
Cowper's gland. 
Fossa navicularis. 
Fig. 1037.-Vertical section of bladder, penis, and urethra. 
sex, and the degree of distention of the organ. During infancy it is conical in 
shape, and projects above the symphysis pubis into the hypogastric region. In the 
adult, when quite empty and contracted (Figs. 1035 and 1036), it is cup-shaped, 
and on vertical median section its cavity, with the adjacent portion of the urethra, 
presents a Y-shaped cleft, the stem of the Y corresponding to the urethra. It is 7WA; urinary bladder 
1433 
placed deeply in the pelvis, flattened from before backward, and reaches as high as 
the upper border of the symphysis pubis. When slightly distended, it has a rounded 
form, and is still contained within the pelvic cavity (Fig. 1036), and when greatly 
distended (Figs. 1036 and 1037), it is ovoid in shape, rising into the abdominal 
cavity, and often extending nearly as high as the umbilicus. It is larger in its verti- 
cal diameter than from side to side, and its long axis is directed from above 
obliquely downward and backward, in a line directed from some point between 
the symphysis pubis and umbilicus (according to its distention) to the end of the 
coccyx. The bladder, when distended, is slightly curved forwarjl toward the 
Recto-vesical 
pouch. 
Peritoneum 
Vesicula seminalis. 
Symphysis pubis. 
Prostate 
gland. 
Dorsal vein of penis. 
^Sphincter ani. 
Septum pectiniforme. 
Urethra. 
Prostatic sinus. 
Accelerator urines. 
Fig. 1038.-Vertical median section of the male pelvis. (Henle.) 
anterior wall of the abdomen, so as to be more convex behind than in front. In 
the female it is larger in the transverse than in the vertical diameter, and its 
capacity is said to be greater than in the male.1 When moderately distended, it 
measures about five inches in length, and three inches across, and the ordinary 
amount which it can contain without serious discomfort is about a pint. 
The bladder is divided for purposes of description into a superior, an antero- 
inferior, and two lateral surfaces, a base or fundus, and a summit or apex. 
Surfaces. The Superior or Abdominal Surface (Figs. 852, 1037, 1038, and 1055). 
-The superior or abdominal surface is entirely free, and is covered throughout by 
1 According to Henle, the bladder is considerably smaller in the female than in the male.-En. of 15th 
English edition. THE URINARY ORGANS 
1434 
peritoneum. It looks almost directly upward into the abdominal cavity, and extends 
in an antero-posterior direction from the apex to the base of the bladder. It is in 
relation with the small intestine and sometimes with the sigmoid flexure, and, in 
the female, with the uterus. On each side, in the male, a portion of the vas 
deferens is in contact with the hinder part of this surface, lying beneath the 
peritoneum. 
The Antero-inferior or Pubic Surface (Figs. 1037, 103S, and 1055).-The antero- 
inferior or pubic surface looks downward and forward. In the undistended 
condition it is uncovered by peritoneum, and is in relation with the Obturator 
intemus muscle on each side, with the recto-vesical fascia, and anterior true 
ligaments of the bladder. It is separated from the body of the pubis by a tri- 
angular interval, the space of Retzius, occupied by fatty tissue. As the bladder 
External iliac 
artery. 
Anterior crural 
( nerve. 
External oblique 
muscle. 
Vermiform appendix. 
Profunda vessels. 
LEVATOR ANI. 
Corpora 
cavernosa. 
Urethra. 
Fig. 1039.-Frontal section of the lower part of the abdomen. Viewed from in front. (Braune.) 
ascends into the abdominal cavity during distention the distance between its apex 
and the umbilicus is necessarily diminished, and the urachus (Fig. 852 and 1055) 
is thus relaxed; so that, instead of passing directly upward to the umbilicus, it 
descends first on the upper part of the anterior surface of the bladder, and then, 
curving upward, ascends on the back of the abdominal wall. The peritoneum, 
which follows the urachus, thus comes to form a pouch (plica vesicalis transversal 
of varying depth between the anterior surface of the viscus and the abdominal 
wall (Fig. 1038). The fold passes to the neighborhood of the internal abdom- 
inal rings. Thus, when the bladder is distended, the upper part of its anterior 
surface is in relation with the urachus and is covered by peritoneum. The lower 
part of its anterior surface, a distance of about two inches above the symphysis 
pubis, is devoid of peritoneum, and is in contact with the abdominal wall. THE URINARY BLADDER 
1435 
The Lateral Surfaces.-The lateral surfaces are covered behind and above by 
peritoneum, which extends as low as the level of the obliterated hypogastric 
artery; below and in front of this, these surfaces are uncovered by peritoneum, 
and are separated from the Levatores ani muscles and walls of the pelvis by a 
quantity of loose areolar tissue containing fat. Tn front this surface is connected 
to the recto-vesical fascia by a broad expansion on either side, the lateral true 
ligaments. The vas deferens crosses the hinder part of the lateral surface obliquely, 
and passes between the ureter and the bladder. When the bladder is empty the 
peritoneum descends on the pelvic wall as low as the lateral border of the bladder 
and enters a groove known as the paravesical fossa. The lateral surfaces, the 
pubic surface, and the abdominal surface together constitute the body of the 
bladder (corpus vesicae). 
The Fundus or Base (fundus vesicae) (Figs. 1038, 1052, and 1055).-The fundus 
or base is directed downward and backward, and is partly covered by peritoneum 
and is in part not covered by it. In the male the upper portion, to within about 
an inch and a half of the prostate, is covered by the recto-vesical pouch of peri- 
toneum (Fig. 855). The lower part is in direct contact with the anterior wall of 
the second part of the rectum and the vesiculae seminales and vasa deferentia 
(Figs. 1052 and 1054). The ureters enter the bladder at the upper part of its 
base, about an inch and a half above the base of the prostate gland (Fig. 1045). 
The portion of the bladder in relation with the rectum corresponds to a trian- 
gular space, bounded, below, by the prostate gland; above, by the recto-vesical 
fold of the peritoneum; and on each side, by the vesicula seminalis and vas 
deferens. It is separated from direct contact with the rectum by the recto- 
vesical fascia. When the bladder is very full, the peritoneal fold is raised with 
it, and the distance between its reflection and the anus is about four inches; but 
this distance is much diminished when the bladder is empty and contracted. In 
the female, the base of the bladder is connected to the anterior aspect of the cervix 
uteri by areolar tissue, and is adherent to the anterior wall of the vagina (Fig. 
853). Its upper surface is separated from the anterior surface of the body of 
the uterus by the utero-vesical pouch of the peritoneum (Fig. 853). 
The so-called neck or cervix of the bladder (collum vesicae) is the point of com- 
mencement of the urethra; there is, however, no tapering part, which would 
constitute a true neck, but the bladder suddenly contracts to the opening of the 
urethra (Fig. 1038). In the male it is surrounded by the prostate gland and its 
direction is oblique when the individual is in the erect posture (Figs. 1037 and 
1038). Tn the female its direction is obliquely downward and forward. 
The Summit or Apex (vertex vesicae).-The summit or apex is the portion 
of the bladder which when that organ is empty or nearly empty is nearest to 
the upper border of the symphysis. It is directed upward and forward. In a 
distended bladder the apex is well above the pubes in the abdominal cavity. 
The Urachus or Middle Umbilical Ligament (ligamentum umbilicale medium) 
(Fig. 1055).-The urachus is a connective-tissue cord and is the obliterated 
remains of the tubular canal of the allantois, which existed in the embryo, and 
a portion of which expanded to form the bladder. It passes upward, from the 
apex of the bladder, between the transversalis fascia and peritoneum, to the 
umbilicus, becoming thinner as it ascends. It is composed of fibrous tissue, 
mixed with plain muscular fibres. The urachus causes the formation of a peri- 
toneal fold, the plica umbilicalis media (Fig. 852). On each side of it is placed a 
fibrous cord, the obliterated portion of the hypogastric artery, which, passing 
upward from the side of the bladder, approaches the urachus above its summit. 
Over each cord is the fold known as the plica umbilicalis lateralis (Fig. 852). In 
the infant, at birth, the urachus is occasionally found pervious, so that the urine 
escapes at the umbilicus, and calculi have been found in its canal. THE URINARY ORGANS 
1436 
Ligaments.-The bladder is retained in its place by ligaments, which are divided 
into true and false. The true ligaments are five in number: two anterior, two 
lateral, and the urachus. The false ligaments, also five in number, are formed by 
folds of the peritoneum. 
The two anterior true ligaments, the pubo-prostatic or pubo-vesical ligaments (liga- 
menta puboprostatica) extend from the back of the ossa pubis, one on each side of 
the symphysis, to the front of the neck of the bladder, over the anterior surface of 
the prostate gland. These ligaments are formed by the recto-vesical fascia, and 
contain a few muscular fibres prolonged from the bladder. 
The two lateral true ligaments, formed by expansions from the fascia lining the 
lateral wall of the pelvis, are broader and thinner than the preceding. They 
are attached to the lateral parts of the prostate gland and to the sides of the base of 
the bladder. 
Fig. 1040.-Fibres of the exteral 
longitudinal layer. (Poirier and 
Charpy.) 
Fig. 1041. - Fibres of the middle 
or circular layer. (Poirer and 
Charpy.) 
Fig. 1042.-Fibres of the inter- 
nal longitudinal layer. (Poirier 
and Charpy.) 
The urachus or middle umbilical ligament is the fibro-muscular cord already men- 
tioned, extending between the summit of the bladder and the umbilicus. It is broad 
below, at its attachment to the bladder, and becomes narrower as it ascends. 
The two posterior false ligaments pass forward, in the male, from the sides of 
the rectum (plicae rectovesicales)', in the female, from the sides of the uterus (plicae 
redout erinae), to the posterior and lateral aspect of the bladder; they form in 
the male the lateral boundaries of the recto-vesical pouch (excavatio rectovesical is) 
(Figs. 926 and 1038); they form in the female the lateral boundaries of the pouch or 
cul-de-sac of Douglas (excavatio redouterina [Douglasx]) (Figs. 853 and 927). The 
posterior false ligaments contain the obliterated hypogastric arteries and the 
ureters, together with vessels and nerves. In the base of each fold is smooth 
muscle-fibre, the Recto-vesical muscle (m. redovesicalis). 
The two lateral false ligaments are reflections of the peritoneum, from the 
iliac fossae and lateral walls of the pelvis to the sides of the bladder. Each 
lateral false ligament (ligamentum umbilicale laterale) passes in front into the plica 
umbilicalis lateralis over the corresponding hypogastric artery. The two lateral 
reflections of peritoneum are continuous in front of the apex vesicae, at which 
point the peritoneum passes upon the urachus. 
The superior or anterior false ligament or the suspensory ligament (plica umbilicalis 
media) is the prominent fold of peritoneum extending from the summit of the blad- 
der to the umbilicus. It is carried off from the bladder by the urachus and the THE URINARY BLADDER 
1437 
obliterated hypogastric arteries. The peritoneal fold over each obliterated hypo- 
gastric artery is called the plica umbilicalis lateralis (Fig. 852), and is the pro- 
longation forward of the ligamentum umbilicale laterale. Besides the true and 
false ligaments, the bladder receives support from the fibrous tissue and unstriated 
muscle about the seminal vesicles, and terminations of the ureters and vasa defer- 
entia. In the female the connection with the anterior vaginal wall supports the 
base of the bladder. In both sexes the most solidly fixed part of the bladder is 
about the orifice of the urethra. 
Structure.-The bladder is composed of four coats-serous, muscular, sub- 
mucous, and mucous. 
The Serous Coat (tunica serosa).-The serous coat is partial, and derived from the 
peritoneum. It invests the superior surface and the upper part of the lateral surfaces 
and base, and is reflected from these parts on to the abdominal and pelvic walls. 
The Muscular Coat (tunica muscularis) (Figs. 1040, 1041, and 1042).-The mus- 
cular coat consists of three layers of unstriped muscular fibre: an external layer, 
composed of fibres having for the most part a longitudinal arrangement; a middle 
layer, in which the fibres are arranged, more or less, in a circular manner; and an 
internal layer, in which the fibres have a general longitudinal arrangement. 
The fibres of the external longitudinal layer (stratum externum) arise from the 
posterior surface of the body of the os pubis in both sexes (m. pubovesicalis), and 
in the male arise also from the adjacent part of the prostate gland and its capsule. 
They pass, in a more or less longitudinal manner, up the anterior surface of the 
bladder, over its apex, and then descend along its posterior surface to its base, 
where they become attached to the prostate in the male and to the front of the vagina 
in the female. At the sides of the bladder the fibres are arranged obliquely anti 
intersect one another. The external lorgitudinal layer has been named the 
Detrusor urinae muscle. 
The middle circular layers (stratum medium) are very thinly and irregularly 
scattered on the body of the organ, and, though to some extent placed transversely 
to the long axis of the bladder, are for the most part arranged obliquely. Toward 
the lower part of the bladder, around the neck and the commencement of the 
urethra, they are disposed in a thick circular layer, forming the sphincter vesicae, 
which is continuous with the muscular fibres of the prostate gland. 
The internal longitudinal layer (stratum internum) is thin, and its fasciculi have 
a reticular arrangement, but with a tendency to assume for the most part a longi- 
tudinal direction. Two bands of oblique fibres, originating behind the orifices of 
the ureters, converge to the back part of the prostate gland, and are inserted, by 
means of a fibrous process, into the middle lobe of that organ. They are the 
muscles of the ureters, described by Sir C. Bell, who supposed that during the con- 
traction of the bladder they served to retain the oblique direction of the ureters, 
and so prevent the reflux of the urine into them. 
The Submucous Coat (tela submucosa).-The submucous coat consists of a layer 
of areolar tissue connecting together the muscular and mucous coats, and inti- 
mately united to the latter. 
The Mucous Coat (tunica mucosa).-The mucous coat is thin, smooth, and of a 
pale rose color. It is continuous above through the ureters with the lining mem- 
brane of the uriniferous tubes, and below with that of the urethra. Except at the 
trigone, it is connected very loosely to the muscular coat by a layer of areolar tissue, 
and is therefore thrown into folds or rugae when the bladder is empty (Fig. 
1046). The mucous membrane over the trigone never presents rugae. The 
epithelium covering it is of the transitional variety, consisting of a superficial 
layer of polyhedral flattened cells, each with one, two, or three nuclei (Fig. 1043); 
beneath these is a stratum of large club-shaped cells with the narrow extremity of 
each cell directed downward and wedged in between smaller spindle-shaped cells, 1438 
THE URINARY ORGANS 
each an oval nucleus (Fig. 1044). There are no true glands in the mucous mem- 
brane of the bladder, though certain mucous follicles which exist, especiallv near 
the neck of the bladder, have been regarded as such. 
Objects Seen on the Inner Surface.-Upon the inner surface of the bladder are 
seen the mucous membrane, orifices of the ureters, the trigone, and the commencement 
of the urethra. 
Fig. 1043.-Superficial layer of the epithelium of 
the bladder. Composed of polyhedral cells of vari- 
ous sizes, each with one, two, or three nuclei. (Klein 
and Noble Smith.) 
Fig. 1044.-Deep layers of epithelium of bladder, 
showing large club-shaped cells above, and smaller, 
more spindle-shaped cells below, each with an oval 
nucleus. (Klein and Noble Smith.) 
The Mucous Membrane.-The mucous membrane of the empty bladder is thrown 
into folds or rugae, except over the trigone, where it is firmly adherent to the 
muscular coat and is smooth (Figs. 1045 and 1046). The folds disappear when 
the bladder is distended. 
The Orifices of the Ureters (Figs. 1045 and 1046).-These are situated at the base 
of the trigone, being distant from each other about two inches when the bladder is 
ORIFICES OF 
URETERS 
VAS 
DEFERENS 
SEMINAL 
VESICLE 
•URETER 
RIDGE FORMED BY 
INTERURETERAL 
MUSCLE 
Fig. 1045.-The interior of the bladder, showing the vesical trigone. (Poirier and Charpy.) 
moderately distended. Each orifice is about an inch and a half from the base of the 
prostate and the commencement of the urethra in the moderately distended bladder. 
The Vesical Trigone or the Trigonum Vesicae (Fig. 1045) is a triangular smooth 
surface, with the apex directed forward, situated at the base of the bladder, imme- 
diately behind the urethral orifice. It is paler in color than the rest of the THE URINARY BLADDER 
1439 
interior, and never presents any rugae, even in the collapsed condition of the 
organ, owing to the intimate adhesion of its mucous membrane to the subjacent 
tissue. It is bounded at each posterior angle by the orifice of a ureter, and in 
front by the orifice of the urethra. Projecting from the lower and anterior part of 
the bladder, and reaching to the orifice of the urethra, is a slight elevation of 
mucous membrane, particularly prominent in old persons, called the uvula vesicae. 
It is formed by a thickening of the submucous tissue. 
Stretching from one ureteral opening to the other is a smooth, slightly curved 
ridge, the convexity of which is toward the urethra. It is produced by transverse 
muscle-fibres beneath the mucous membrane. The outer prolongations of this 
ridge beyond the ureteral orifices are called the ureteral folds (plicae uretericae). 
They are created by the ureters as they traverse the bladder wall. About the 
ureteral orifice are slight radial folds of mucous membrane, which are continuous 
with the longitudinal folds of the prostatic urethra. "In the empty bladder the 
ureteral orifice and the openings of the two ureters lie at the angles of an approxi- 
mately equilateral triangle, whose sides are about one inch in length. When the 
bladder is distended the distance between the openings may be increased to one 
and a half inches or more."1 
LONGITUDINAL 
FIBRES 
CIRCULAR 
FIBRES 
-URETER 
-TRIGONE 
TRANSVERSE 
FIBRES OF 
TRIGONE 
LONGITUDI N AL 
FIBRES OF 
TRIGONE 
'PROSTATE 
.EJACULATORY 
DUCT 
PROSTATE 
Fia. 1046.-The internal surface of the bladder. (Poirier and Charpy), 
The muscles of the ureters were referred to on p. 1437. 
The internal urethral orifice (orificium urethrae internum) is sickle-shaped and 
is surrounded by a circular prominence (annulus urethralis), which is most distinct 
in the male. 
Vessels and Nerves.-The arteries (Fig. 424) supplying the bladder are the 
superior, middle, and inferior vesical in the male, with additional branches from 
the uterine and vaginal in the female. They are all derived from the anterior 
trunk of the internal iliac. The obturator and sciatic arteries also supply small 
visceral branches to the bladder. The veins form a complicated plexus around the 
neck, sides, and base of the bladder (Fig. 474). The veins communicate below 
with the plexus about the prostate and terminate in the internal iliac vein. 
The lymphatics form two plexuses, one in the muscular and another in the sub- 
mucous coat. They accompany the blood-vessels. The mucous membrane of 
the bladder contains no lymphatics whatever (Sappey). The muscular tissue 
contains a few lymphatics. The subperitoneal tissues contain the usual number. 
1 Professor A. Francis Dixon, in Prof. D. J. Cunningham's Text-book of Anatomy. THE URINARY ORGANS 
1440 
The collecting trunks from the anterior surface terminate in the external iliac 
glands. The trunks from the posterior surface terminate in the internal iliac 
glands, the hypogastric glands and the glands in front of the sacral promontory. 
The nerves are derived from the pelvic plexus of the sympathetic and from the 
third and fourth sacral nerves; the former supplying the upper part of the organ, 
the latter its base and neck. According to F. Darwin, the sympathetic fibres have 
ganglia connected with them, which send branches to the vessels and to the 
muscular coat. 
Surface Form.-The surface form of the bladder varies with its degree of distention and 
under other circumstances. In the young child it is represented by a conical figure, the apex 
of which, even when the viscus is empty, is situated in the hypogastric region, about an inch 
above the level of the symphysis pubis. In the adult, when the bladder is empty, its apex does 
not reach above the level of the upper border of the symphysis pubis, and the whole organ is 
situated in the pelvis; the neck, in the male, corresponding to a line drawn horizontally backward 
through the symphysis a little below its middle. As the bladder becomes distended, it gradually 
rises out of the pelvis into the abdomen, and forms a swelling in the hypogastric region, which is 
perceptible to the hand as well as to percussion. In extreme distention it reaches into the umbil- 
ical region. Under these circumstances the lower part of its anterior surface, for a distance 
of about two inches above the symphysis pubis, is closely applied to the abdominal wall, without 
the intervention of peritoneum, so that it can be tapped by an opening in the middle line just 
above the symphysis pubis, without any fear of wounding the serous membrane. When the 
rectum is distended, the prostatic portion of the urethra is elongated and the bladder lifted out 
of the pelvis and the peritoneum pushed upward. Advantage is taken of this by some surgeons 
in performing the operation of suprapubic cystotomy. The rectum is distended by an India- 
rubber bag, which is introduced into this cavity empty, and is then filled with ten or twelve ounces 
of water. If now the bladder is injected with about half a pint of some antiseptic fluid, it will 
appear above the pubes plainly perceptible to the sight and touch. The peritoneum will be 
pushed out of the way, and an incision three inches long may be made in the linea alba, from 
the symphysis pubis upward, without any great risk of wounding the peritoneum. Other sur- 
geons object to the employment of this bag, as its use is not unattended with risk, and because 
it causes pressure on the prostatic veins and hence produces congestion of the vessels over the 
bladder and a good deal of venous hemorrhage. 
When distended, the bladder can be felt in the male, from the rectum, behind the prostate, 
and fluctuation can be perceived by a bimanual examination, one finger being introduced into the 
rectum and the distended bladder being tapped on the front of the abdomen with the finger 
of the other hand. This portion of the bladder-that is, the portion felt in the rectum by the 
finger-is uncovered by peritoneum. 
Surgical Anatomy.-A certain defect of development in which the bladder is implicated is 
known under the name of extroversion of the bladder. In this condition the lower part of the 
abdominal wall and the anterior wall of the bladder are wanting, so that the posterior surface 
of the bladder presents on the abdominal surface, and is pushed forward by the pressure of the 
viscera within the abdomen, forming a red, vascular protrusion, on which the openings of the 
ureters are visible. The penis, except the glans, is rudimentary and is cleft on its dorsal sur- 
face, exposing the floor of the urethra-a condition known as.epispadias. The pelvic bones 
are also arrested in development (see page 220). 
The bladder may be ruptured by violence applied to the abdominal wall when the viscus is 
distended without any injury to the bony pelvis, or it may be torn in case of fracture of the 
pelvis. The rupture may be either intraperitoneal or extraperitoneal-that is, may implicate the 
superior surface of the bladder in the former case, or one of the other surfaces in the latter. 
Rupture of the antero-inferior surface alone is, however, very rare. Until recently intraperi- 
toneal rupture was uniformly fatal, but now abdominal section and suturing the rent with Lem- 
bert sutures often saves the patient. The sutures are inserted only through the peritoneal and 
muscular coats in such a way as to bring the serous surfaces at the margins of the wound into 
apposition, and one is also inserted just beyond each end of the wound. The bladder should be 
tested as to whether it is water-tight before closing the external incision. 
The muscular coat of the bladder undergoes hypertrophy in cases in which there is any per- 
sistent obstruction to the flow of urine. Under these circumstances the bundles of which the 
muscular coat consists become much increased in size, and, interlacing in all directions, give rise 
to what is known as the fasciculated bladder. Between these bundles of muscular fibres the mucous 
membrane may bulge out, forming sacculi, constituting the sacculated bladder, and in these 
little pouches phosphatic concretions may collect, forming encysted calculi. The mucous mem- 
brane is very loose and lax, except over the trigone, to allow of the distention of the viscus. 
Various forms of tumors have been found springing from the wall of the bladder. The inno- THE MALE URETHRA 
1441 
cent tumors are the papilloma and the mucous polypus, arising from the mucous membrane; 
the fibrous tumor, from the submucous tissue; and the myoma, originating in the muscular 
tissue; and, very rarely, dermoid tumors, the exact origin of which it is difficult to explain. 
Of the malignant tumors, epitheliomata are the most common, but sarcomata are occasionally 
found in the bladders of children. 
Puncture of the bladder is performed above the pubes without wounding the peritoneum. 
Puncture by the rectum is not now performed, as a permanent fistula may be left from abscess 
forming between the rectum and the bladder; or pelvic cellulitis maybe set up; moreover, it is 
exceedingly inconvenient to keep a cannula in the rectum. In some cases in performing this 
operation the recto-vesical pouch of peritoneum has been wounded, inducing fatal peritonitis. 
'The operation, therefore, has been abandoned. Suprapubic cystotomy is considered above under 
the heading of Surface Form. This operation may be employed to permit of the removal of a 
calculus and is then called suprapubic lithotomy. 
THE MALE URETHRA (URETHRA VIRILIS) (Figs. 1047, 1048, 1049, 1050, 1054). 
The urethra in the male extends from the neck of the bladder at the internal 
orifice of the urethra (orificium urethrae internum) to the meatus urinarius, the 
external orifice of the urethra (orificium urethrae 
externum), at the end of the penis. The in- 
ternal orifice has been described (p. 1439). The 
urethra presents a double curve in the flaccid 
state of the penis (Fig. 1054), but in the erect 
state of this organ it forms only a single curve, 
the concavity of which is directed upward. Its 
length varies from eight to nine inches; and it 
is divided into three portions, the prostatic, 
membranous, and spongy, the structure and re- 
lations of which are essentially different. Ex- 
cept during the passage of the urine or semen, 
the urethra is a mere cleft or slit, transverse, T- 
shaped or crescentic (Fig. 1049), with its upper 
and under surfaces in contact. At the meatus 
urinarius the slit is vertical, and in the prostatic 
portion somewhat arched (Fig. 1049). 
The First or Prostatic Portion (pars pros- 
tatica) (Figs. 1037, 1047, 1048, 1055, and 1056). 
-The first or prostatic portion is the widest and 
most dilatable part of the canal. It is between 
the internal orifice of the urethra and the supe- 
rior layer of the triangular ligament and is within 
the pelvic cavity. It passes between the two 
lateral lobes of the prostate gland, from the base 
to the apex of the gland, lying nearer its ante- 
rior than its posterior surface. The gland seems 
to completely surround this portion of the 
urethra (Fig. 1053), but the glandular matter of 
the gland does not (Fig. 1051). The gland is like 
a buckle open in front, and the open part of the 
buckle is closed by the prostatic muscle. The 
prostatic urethra is about an inch and a quarter 
in length; the form of the canal is spindle- 
shaped, being wider in the middle than at either 
extremity, and narrowest below, where it joins the membranous portion. Except 
during the passage of fluid, the canal is in a collapsed state, the anterior wall resting 
upon the posterior wall (Fig. 1049), and the mucous membrane exhibiting longitu- 
Crest of the, 
urethra. 
Prostatic 
portion. 
Verumon- 
tanum.' 
Prostate. - 
Cowper's gland. 
Bulb.' 
Membranous 
portion. 
Crus. 
Corpus 
cavemosum.' 
Spongy portion. 
Corpus 
spongiosum. 
Glans.- 
Fossa 
navic. 
Fig. 1047.-The male urethra, laid open on 
its anterior (upper) surface. (Testut.) 
Meatus. 1442 
THE URINARY ORGANS 
dinal folds. When distended, the largest portion of the prostatic urethra has a 
diameter of about one-third of an inch. A transverse section of the canal as it 
lies in the prostate is horseshoe-shaped, the convexity being directed forward 
(Figs. 1049 and 1051). The direction of the canal is nearly vertical, there being 
a slight curve, which is concave forward (Figs. 1037 and 1038). 
Upon the posterior wall or floor of the canal is a narrow longitudinal ridge, the 
crest of the urethra (crista urethralis), formed by an elevation of the mucous mem- 
brane and its subjacent tissue (Fig. 1047). This crest begins at the uvula vesicae, 
and passes through the prostatic portion and into the membranous portion of the 
urethra (Fig. 1056), and usually bifurcates at its distal end; it contains, according to 
Kobelt, muscular and erectile tissues. On this longitudinal ridge is an enlargement, 
the verumontanum or caput gallinaginis (colliculus seminalis) (Figs. 1047 and 1056). 
When distended, it may serve to prevent the passage of the semen backward into 
the bladder. On each side of the verumontanum is a slightly depressed fossa, the 
floor of which is perforated by numerous apertures, the orifices of the prostatic ducts 
(Figs. 1047 and 1056), from the lateral lobes of the glands; the ducts of the middle 
MUSCULAR WALL 
OF BLADDER 
PROSTATIC 
SINUS 
LONGITUDINAL MUS- 
CLES OF URETHRA 
CORPUS 
SPONGIOSUM 
Fig. 1048.-Proximal portions of urethra with surrounding parts. (After Testut.) 
lobe open behind the verumontanum. At the forepart of the verumontanum, in the 
middle line, is a depression, the prostatic sinus, prostatic utricle, prostatic vesicle, 
uterus masculinus or sinus pocularis (utriculus prostaticus) (Figs. 1038 and 1056); and 
upon or within its margins are the slit-like openings of the ejaculatory ducts (ductus 
ejaculatorii) (Fig. 1056). The sinus pocularis forms a cul-de-sac about a quarter of 
an inch in length, which runs upward and backward in the substance of the pros- 
tate behind the transverse band of prostatic tissue which joins the lateral lobes 
behind the posterior wall of the urethra; its prominent anterior wall partly forms 
the verumontanum. Its walls are composed of fibrous tissue, muscular fibres, 
and mucous membrane, and numerous small glands open on its inner surface. 
It has been called by Weber, who discovered it, the uterus masculinus, from its 
being developed from the united lower ends of the atrophied Mullerian ducts, 
and therefore being homologous with the uterus and vagina in the female. 
The Second, Muscular or Membranous Portion Qx/r.v membranacea) (Figs. 1047, 
1048, and 1056) extends downward and forward between the apex of the prostate 
and the bulb of the corpus spongiosum. It is the narrowest part of the canal (except- 
ing the meatus), and measures three-quarters of an inch along its upper, and half 
an inch along its lower, surface, in consequence of the bulb projecting backward THE MALE URETHRA 
1443 
beneath it. Its anterior concave surface is placed about an inch below and behind 
the pubic arch, from which it is separated by the dorsal vessels and nerves of the 
penis, and some muscular fibres. Its posterior convex surface is separated from 
the rectum by a triangular space, which constitutes the perineum. The membra- 
nous portion of the urethra lies chiefly between the inferior and superior layers of 
the triangular ligament(Fig.309). The termination of this part of the urethra is over- 
lapped by the bulb, and is in front of the triangular ligament 
(Fig. 309). As it pierces the inferior layer, the fibres around 
the opening are prolonged over the tube and fix the two struc- 
tures firmly to each other. The membranous urethra is sur- 
rounded by cavernous tissue and by the Compressor urethrae 
muscle (m. sphincter urethrae wiem6ranaceae)(Fig.31O). On the 
floor of the membranous urethra is the anterior extremity of 
the crista urethralis. Behind this part of the urethra, on each 
side of the middle line, are Cowper's glands (Figs. 308 and 1056). 
The canal enters the bulb a little in front of the posterior 
extremity, and the anterior wall or roof of the membranous 
urethra is a little longer than the posterior wall or floor. The 
backward projection of the bulb hangs over most of the floor 
of the membranous urethra (Figs. 308, 309, 1047, 1056, and 
1058). When the urethra is empty the mucous membrane of 
the second part is thrown into longitudinal folds, which are 
obliterated by distention. 
The Third, Penile, Pendulous, Cavernous or Spongy 
Portion {pars cavernosa) (Figs. 1037,1047,1048, and 1050) is 
the longest part of the urethra* and is contained in the corpus 
A 
B 
C 
D 
E 
F 
G 
15 M M. 
25 MM. 
42 MM. 
88 MM. 
98 MM. 
150 MM. 
155 MM. 
PROBE IN 
LACUNA MAGNA 
CLANS 
RIGHT LIP OF MEATUS 
PREPUCE RETRACTED 
LATERAL LACUN/E 
-SKIN 
-SIDE OF URETHRA 
UPPER WALL OF URETHRA 
LARGE LACUNA 
spongy body-cut surface 
spongy body-cut surface. 
MEDIAN LACUN/E 
Fig. 1049. - Cross-sec- 
tionsof the male urethra at 
various distances from its 
free end, showing marked 
alterations of form. (Tes- 
tut.) 
CORPUS 
SPONGIOSUM 
Fig. 1050.-The distal portion of the male urethra, laid open on its posterior 
(under) surface, showing the lacunae. (Testut.) 
spongiosum. It is about six inches in length, and extends from the termination 
of the membranous portion to the meatus urinarius. It is surrounded throughout 
its entire course by the erectile tissue of the corpus spongiosum and glans penis. 
Its proximal end is fixed in position and unchangeable in direction. Its distal end 
is movable and changeable in direction. Commencing just below the triangular 
ligament it is first directed forward through the bulb; it then passes downward 
and forward, the turn beginning at the seat of attachment of the suspensory 
ligament of the penis (Fig. 1037). The direction of the third portion of the urethra 
is changed by alterations in the position of the penis. When the canal is closed the 
anterior and posterior walls are in contact (roof and floor), except in the glans 1444 
THE URINARY ORGANS 
penis, where the lateral walls come together. "Thus the first part of the canal 
when empty is represented in cross-section by a transverse slit, and the terminal 
part by a vertical slit (Fig. 1049). The calibre of the spongy urethra varies in 
different portions of the tube. It is of larger diameter in the bulb (bulbous por- 
tion of urethra) and in the glans than between these two points. In the body of 
the penis the canal is of uniform size, and is about one-quarter of an inch in 
diameter. The fossa navicularis (fossa navicularis urethrae {Morgagni}) is an 
oblong dilatation of the terminal portion of the penile urethra (Figs. 1037, 1047, 
and 1060). In the front of the fossa navicularis there is a transverse fold of 
mucous membrane, the valve of Guerin (valvulae fossae navicularis). It is part 
of a distinct depression or pocket. The fossa navicularis opens anteriorly by 
the meatus urinarius. 
The meatus urinarius or external orifice of the urethra (orificium urethrae externum) 
(Figs. 1047 ami 1059) is the most contracted part of the urethra; it is a vertical slit 
(Fig. 1049),about three lines in length,bounded on each side by a small lip or labium. 
The inner surface of the lining membrane of the urethra, especially on the floor 
of the spongy portion, presents the orifices of numerous mucous glands (Fig. 1050) 
situated in the submucous tissue, and named the glands of Littr^ (glandulae ure- 
thrales). A number of little recesses or follicles, called lacunae (lacunae urethrales), 
open into the penile urethra. Some of the glands of Littre open into the lacunae; 
some do not. They vary in size, and their orifices are directed forward, so that they 
may easily intercept the point of a catheter in its passage along the canal. One 
of these lacunae, larger than the rest, is situated in the upper surface of the fossa 
navicularis, about half an inch from the orifice; it is called the lacuna magna (Fig. 
1060). Into the bulbous portion are found opening the ducts of Cowper's glands. 
Structure.-The urethra is composed of a continuous mucous membrane, 
supported by a submucous tissue which connects it with the various structures 
through which it passes. 
The Mucous Coat.-The mucous coat forms part of the genito-urinary mucous 
membrane. It is continuous with the mucous membrane of the bladder, ureters, 
and kidneys; externally with the integument covering the glans penis; and is pro- 
longed into the ducts of the glands which open into the urethra-viz., Cowper's 
glands and the prostate gland-into the vasa deferentia and the seminal vesicles 
through the ejaculatory ducts. The mucous membrane is arranged in longitudinal 
folds when the tube is empty. Small papillae are found upon it near the orifice, 
and its epithelial lining is of the columnar variety, excepting near the meatus, 
where it is squamous. 
The Glands and Crypts of the Urethral Mucous Membrane (Fig. 1049).-There is a 
pocket, the lacuna magna (Fig. 1060;, opening to the front in the upper wall of the 
fossa navicularis. The fossa is bounded by the valve of Guerin (valvulae fossa navic- 
ularis). The lacunae of Morgagni are in the spongy urethra back of the valve of 
Guerin. The lacunae look forward. The largest of them is on the roof of the fossa 
navicularis, one and one-half inches from the orifice (see above). Some of the 
lacunae receive the secretion from the glands of Littre; others do not, because some 
of the glands open on the free surface. The larger lacunae are one-third of an inch 
deep and are placed in a longitudinal row upon the anterior wall. The smaller 
lacunae are in longitudinal rows at the sides of the tube. The glands of Morgagni 
are present throughout the urethra,except in its most anterior part. In the prostatic 
urethra they are arranged in rows. In the membranous urethra they are scat- 
tered irregularly. In the spongy portion they are most numerous on the anterior 
wall and are more plentiful on the sides than on the floor. Besides the lacunae and 
racemose glands, there are the opening of the prostatic glands, the ejaculatory 
ducts, Cowper's glands, and the opening of the sinus pocularis. 
1 Professor A. Francis Dixon, in Professor D. .1. Cunningham's Text-book of Anatomy. THE MALE URETHRA 
1445 
The Submucous Tissue.-The submucous tissue consists of a vascular erectile 
layer. It contains the glands of Littre, especially in the posterior part. These 
glands are lined with cylindrical epithelium and enter the submucous coat. 
The Muscular Layer.-The muscular layer is continuous with the muscle of the 
prostate and bladder. It is composed of non-striated muscle arranged in an 
outer layer of circular fibres (stratum circulars) and an inner layer of longitudinal 
fibres (stratum long itud inale). It is placed external to the submucous coat. In 
the penile urethra there is only a thin layer of longitudinal fibres. In the mem- 
branous urethra and the prostatic urethra there are two layers of muscle, an inner 
thin layer of longitudinal fibres and a thicker layer of circular fibres. The longi- 
tudinal fibres, when contracted, shorten the urethra and increase its diameter. 
'Fhe circular fibres are in a state of tonic contraction and close the urethra. In 
fact, they constitute the real sphincter (Zeissl, Zuckerkandl). The so-called 
sphincter of the urethra, the Accelerator urinae, is a voluntary muscle and is not 
the real sphincter. Outside of the muscular layer of the urethra is the tissue 
of the corpus spongiosum. 
Surgical Anatomy. -The urethra may be ruptured by the patient falling astride of any hard 
substance and striking his perinseum, so that the urethra is crushed against the pubic arch. 
Bleeding will at once take place from the urethra, and this, together with the bruising in the 
perinseum and the history of the accident, will at once point to the nature of the injury. 
Rupture of the urethra leads to extravasation of urine. In rupture back of the superior layer 
of the triangular ligament the urine usually follows the rectum and reaches the margin of the 
anus. Rupture between the two layers of the triangular ligament liberates urine between the 
two layers, where it remains until a path of exit is made by suppuration or the surgeon's knife. 
In rupture in front of the anterior layer of the ligament the urine passes into the scrotum and 
may mount up to the abdomen between the symphysis and the pubic spine, between which 
points the deep layer of the superficial fascia is not attached. It cannot pass to the thigh nor 
cross the mid-line, because the fascia is attached to the fascia lata and at the mid-line. 
The surgical anatomy of the urethra is of considerable importance in connection with the 
passage of instruments into the bladder. Otis was the first to point out that the urethra is 
capable of great dilatation, so that, excepting through the external meatus, an instrument corre- 
sponding to 18 English gauge (29 French) can usually be passed without damage. The orifice 
of the urethra is not so dilatable, and therefore may require slitting, although the introduction 
of the Oberlander dilator, which is expanded after introduction, renders slitting of the meatus 
seldom necessary in cases of chronic gonorrhoea. A recognition of this dilatability caused Bige- 
low to very considerably modify the operation of lithotrity and introduce that of litholapaxy. 
In passing a fine catheter, the point of the instrument after it has passed the lacuna magna 
should be kept as far as possible along the upper wall of the canal, as the point is otherwise 
very liable to enter one of the lacunae. Stricture of the urethra is a disease of very common 
occurrence, and is generally situated in the spongy portion of the urethra, most commonly in 
the bulbous portion, just in front of the membranous urethra, but in a very considerable num- 
ber of cases in the penile or ante-scrotal part of the canal. Even in a normal urethra, and very 
markedly in an inflamed urethra, a bougie encounters resistance behind the bulb. This is 
usually supposed to be due to spasm of the Compressor urethrae muscle. 
In irrigation of the urethra by gravity fluid tends to block at the same point, especially if it is 
thrown in suddenly or forcibly. If a reservoir is raised seven and one-half feet from the floor, 
and if a patient sits on a chair or lies upon a bed, fluid can be readily made to pass by hydraulic 
pressure from the meatus to the bladder. Spasm may temporarily prevent the inflow, but the 
weight of the column of fluid soon tires out the muscle and causes it to relax. Relaxation 
is favored by having the patient take slow, deep breaths and make efforts at urination 
(Valentine). 
Chronic gonorrhoea is frequently kept up by persistent inflammation of the ducts and follicles in 
the mucous membrane. This condition is known as chrome glandular urethritis or para- 
urethritis. In these crypts and glands gonococci may remain when gonorrhoea appears to have 
passed away, and from time to time reinfection of the urethra may arise from such a source. 
Median urethrotomy or perineal section is opening of the membranous urethra. Through such 
an opening the bladder can be drained and explored, and the operation is sometimes called 
median cystotomy. 
In lateral lithotomy the knife enters the membranous urethra and strikes the groove of the 
staff. Its edge is then turned toward the left ischial tuberosity and is carried along the groove 
into the bladder, dividing the membranous urethra, the prostatic urethra, the posterior layer of 
the triangular ligament, the Compressor urethrae muscle, anterior fibres of the Levator ani 
muscle and the left lobe of the prostate gland. 1446 
THE URINARY ORGANS 
THE FEMALE URINARY BLADDER. 
The female bladder is situated at the anterior part of the pelvis. It is in relation, in 
front, with the symphysis pubis; behind, with the utero-vesical pouch of peritoneum, 
which separates it from the body of the uterus; its base lies in contact with the 
connective tissue in front of the cervix and upper part of the vagina. Laterally, 
is the recto-vesical fascia. The bladder is said by some anatomists to be larger in 
the female than in the male. At any rate, it does not rise above the symphysis 
pubis till more distended than in the male, but this is perhaps owing to the more 
capacious pelvis rather than to its being of actually larger size. It is described 
in the section on the Bladder (p. 1431). 
THE FEMALE URETHRA (URETHRA MULIEBRIS) 
The female urethra is a narrow membranous canal, about an inch and a half in 
length, extending from the internal urethral orifice {orijidum urethrae internum) 
at the neck of the bladder to the vestibule of the vagina, where it ends, being 
called at its termination the external orifice of the urethra or the meatus urinarius 
{orifidum urethrae externum). The meatus is usually a vertical slit. The 
urethra is placed behind the symphysis pubis, embedded in the anterior wall 
of the vagina; and its direction is obliquely downward and forward, its course 
being slightly curved, the concavity directed forward and upward. Its diameter 
when undilated is about a quarter of an inch. The urethra perforates both 
layers of the triangular ligament, and its external orifice is situated directly in 
front of the vaginal opening and about an inch behind the glans clitoridis. Except 
above, the posterior wall of the urethra is firmly connected to the anterior wall 
of the vagina. 
Structure.-The urethra consists of three coats: muscular, erectile, and mucous. 
The Muscular Coat {tunica muscularis).-The muscular coat is continuous with 
that of the bladder; it extends the whole length of the tube, and consists of an 
internal layer of non-striated longitudinal fibres {stratum longitudinals) and an 
external layer of non-striated circular fibres {stratum circulare). Superficial to the 
circular fibres "lies a layer of cross-striped muscle-fibres, which form a closed ring 
near the bladder only.''1 
The Submucous Coat {tunica submucosa,).-Internal to the muscular coat is the 
submucous coat, which contains a venous plexus, networks from which pass 
between the muscular layers and impart to these layers an erectile or spongy 
nature {corpus spongiosum urethrae). In addition to this, between the two layers 
of the triangular ligament, the female urethra is surrounded by the Compressor 
urethrae muscle, as in the male. 
The Mucous Coat tunica mucosa).-The mucous coat is pale, continuous exter- 
nally with that of the vulva, and internally with that of the bladder. It is thrown 
into longitudinal folds, one of which, placed along the floor of the canal, extends 
from the vesical trigone almost to the external orifice of the urethra. It is called 
the crest {crista urethralis). The outline of the urethra is stellate when collapsed,, 
because of the formation of numerous longitudinal folds. It is lined by laminated 
epithelium, which becomes transitional near the bladder. Many mucous glands 
open into the urethra, and there are numerous lacunae. External to the external 
orifice, on each side, a group of mucous glands opens by a common duct, the 
ductus para-urethralis. 
The urethra, because it is not surrounded by dense resisting structures, as in the male, admits 
of great dilatation, which enables the surgeon to remove with considerable facility calculi or 
other foreign bodies from the cavity of the bladder. 
1 Hand Atlas of Human Anatomy. By Prof. Werner Spalteholz. Translated and edited by Prof. Lewellys F. 
Barker. THE MALE ORGANS OF GENERATION 
THE PROSTATE GLAND (PROSTATA) (Figs. 1048, 1051, 1052, 1053, 1054, 
1055, 1056, 1057). 
THE prostate gland (Ttpoiarr^u, to stand before) is a structure accessory to the 
true generative organs and furnishes a viscid, opalescent secretion in which 
spermatozoids will live (W. G. Richardson). It is a pale, firm, partly glandular 
and partly muscular body, which is 
placed immediately below the neck of the 
bladder and about the commencement of 
the urethra in the male. The prostate 
appears to completely surround the first 
portion of the urethra (Figs. 1053 and 
1057), but the glandular matter does not 
in reality completely surround the tid)e 
(Figs. 1051 and 1057). As Spalteholz 
says, it partly surrounds it as a broad 
clasp, open in front. This opening in the 
glandular tissue is closed, and a com- 
plete ring is established about the urethra 
by the prostatic muscle (m. prostaticus) 
Figs. 1051 and 1057). This muscle below is composed of striated fibres and 
is continuous with the Compressor urethrae (m. sphincter urethrae membranaced); 
PROSTATIC 
MUSCLE 
GLANDULAR 
TISSUE 
MUSCULAR 
LAYER OF 
URETHRA 
URETHRA 
EJACULATORY 
DUCT 
Fig. 1051.-Section of the prostate. (Jarjavay.) 
UTRICLE 
PROSTATIC 
MUSCLE 
SUPERFICIAL 
TRANSVERSE 
PERIN EAL 
MUSCLE 
COM PRESSOR 
URETHRAE MUSCLE 
TRANSVERSE 
PERINEAL LIGAMENT 
Fig. 1052.-Side view of the position of the prostate. (Poirier and Charpy.) 
above it is composed of non-striated muscle, and is continuous with the circular 
muscular fibres of the bladder which surround the internal urethral orifice and 
1447 1448 
THE MALE ORGANS OF GENERATION 
constitute the Sphincter vesicae (Fig. 1052). The general course of the fibres is 
transverse, with radiations into the gland substance. The apex of the gland for 
about one-quarter of an inch is completely surrounded by the muscle (Fig. 1052). 
VAS 
DEFERENS 
AMPULLA 
SEMINAL 
VESICLE* 
EJACULATORY 
DUCT 
ISTHMUS 
URETHRA 
PROSTATE 
Fig. 1053.-Prostate with seminal vesicles and seminal ducts, viewed from in front and above. (Spalteholz.) 
Ascending from the apex the fibres cover for a short distance only the front of the 
gland and are attached at the sides to the fascia (Fig. 1052). Higher up the muscle 
BLADDER- 
PERITONEUM 
AMPULLA 
OF VAS 
DEFERENS 
VAS 
DEFERENS 
EJACULATORY 
DUCT 
PROSTATIC 
UTRICLE 
URETHRA 
PROSTATE 
GLAN D 
.CORPUS 
SPONGIOSUM 
COWPER'S" 
GLAND 
BULB OF 
URETHRA 
COR PUS 
CAVERNOSUM 
ORGAN OF 
GIRALDES 
HYDATID OF 
MORGAGNI 
SCROTUM 
Fig. 1054.-Diagrammatic representation of the male reproduction organs and their relations to the bladder 
and the urethra. Lateral view. (Toldt.) 
passes between the sheath and the capsule and ascends to the base of the prostate, 
uniting the sheath to the capsule along the mid-line in front. The prostate is placed 
in the pelvic cavity, behind the lower part of the symphysis pubis, and above the THE PROSTATE GLAND 
1449 
deep layer of the triangular ligament, and rests upon the rectum, through which 
it may be distinctly felt, especially when enlarged (Fig. 1055.) 
The ejaculatory ducts (Figs. 1053, 1054, and 1056) enter the prostate at the margin 
which separates the base from the posterior surface of the gland; they pass down- 
ward, inward, and forward through the prostate, and open into the prostatic 
urethra. The prostate when surrounded by its sheath resembles a chestnut in 
shape. When dissected out from its sheath and capsule and from the Prostatic 
muscle, it resembles an "open clasp" or horseshoe. The sheath of the prostate 
is derived from the recto-vesical fascia. It is called the prostatic fascia (fascia pro- 
statae), is distinct and dense, and covers the entire prostate, except at the apex and 
at the attachment of the base of the prostate to the neck of the bladder. The pros- 
tatic fascia is a distinct structure, though it is thin. The veins of the prostatic 
plexus lie in the layers of the sheath, "and are everywhere separated from the 
prostatic capsule proper by a layer of this sheath."1 In an enlarged prostate 
the sheath is thick and fibrous. It is very difficult to shell out a normal prostate 
from its sheath, but it is easy to shell out an enlarged prostate. Within the pros- 
tatic sheath (which, be it remembered, carries the veins) is the true or proper capsule 
Fig. 1055.-Sagittal section of the lower part of a male trunk, the right segment. (Testut.) 
1 J. W. Thomson Walker, in the British Medical Journal, July 9, 1904. 1450 
THE MALE ORGANS OE GENERATION 
of the prostate. The true capsule is a continuous investment from the entrance 
of the urethra above to the triangular ligament below. It is thin, but firm and 
fibrous. It is not everywhere absolutely distinct from the sheath, but may be fused 
EJACULATORY 
DUCT 
-UTRICLE 
MOUTH OF EJACU- 
LATORY DUCT 
VERUMONTANUM 
.PROSTATE-CUT SURFACE 
OPENINGS OF 
PROSTATIC DUCTS 
GLAND OF 
COWPER 
MEMBRANOUS URETHRA 
GLAND OF 
COWPER 
-A RIDGE OF 
MUCOSA 
BULBOUS 
URETHRA 
DUCT OF COWPER S 
GLAND - LAID BARE 
CORPUS SPON- 
GIOSUM-CUT SURFACE 
Fig. 1056.-Proximal portion of the urethra, laid open by a median, anterior cut. (Testut.) 
Fig. 1057.-Transverse section of normal prostate through the middle of the verumontanum, from a subject 
aged nineteen years: a, longitudinal section of ducts leading from the lobules of the prostatic glands ; b, veru- 
montanum ; c, sinus pocularis ; d, urethra ; e, ejaculatory ducts ; f, arteries, veins, and venous sinuses in sheath 
of prostate ; g, nerve trunks in sheath ; h, point of origin of fibro-muscular bands encircling urethra ; i, zone of 
striated voluntary muscle on superior surface. (Drawn from Erdinger projection apparatus.) (Taylor.) THE PROSTATE GLAND 
1451 
with it here and there, and many bands of fibres run from the sheath to the capsule.1 
The capsule is continuous with the stroma of the gland and cannot be stripped off as 
can the kidney capsule. Any attempt to strip off the capsule tears away fragments 
of gland. The capsule is composed of fibrous tissue and unstriated muscle-fibres. 
From its deep surface the capsule is continuous with the stroma of the prostate (W. G. 
Richardson). Sir Henry Thompson, half a century ago, pointed out the distinction 
between true capsule and sheath, and suggested these names. The prostate is divided 
for study into a base, apex, posterior surface, anterior surface, and lateral surfaces. 
The Base (basis prostatas).-The base is directed upward, and is situated 
immediately below the base of the bladder. It is in contact with and supports the 
base of the bladder. The external longitudinal muscular layer of the bladder is 
attached to the posterior portion of the base of the prostate, and some of the fibres 
reach and adhere to the true capsule. The anterior portion of the base is called 
the isthmus (isthmus prostatas) (Fig. 1053). 
The Apex (apex prostatas).-The apex is directed downward and rests upon 
the deep layer of the triangular ligament. The apex is fixed, except for the slight 
mobility of the triangular ligament; the rest of the gland is somewhat movable. 
Surfaces.-The Posterior Surface (facies posterior).-The posterior surface is 
flattened, marked by a slight longitudinal furrow, and rests on the second part of 
the rectum, and is distant about one inch and a half from the anus. At the upper 
and posterior border of the gland are the seminal vesicles. Their direction is 
downward and inward; in fact, almost transverse. 
The Anterior Surface (facies anterior).-The anteiior surface is convex, and placed 
about three-fourths of an inch behind the pubic symphysis, from which it is separated 
by a plexus of veins and a quantity of loose fat. It is connected to the pubic bone 
on either side by the pubo-prostatic ligament. It is shorter than the posterior surface. 
The Lateral Surfaces.-The lateral surfaces are prominent, and are covered by 
the anterior portions of the Levatores ani muscles, which are, however, separated 
from the gland by a plexus of veins. 
The prostate measures about an inch and a half transversely at the base, an 
inch in its antero-posterior diameter, and an inch and a quarter in its vertical 
diameter. Its weight is about four and a half drachms. It is held in position 
by the anterior ligaments of the bladder (ligamenta puboprostatica); by the deep 
layer of the triangular ligament, which invests the commencement of the mem- 
branous portion of the urethra and prostate gland; and by the anterior portions of 
the Levatores ani muscles, which pass backward from the os pubis and embrace 
the sides of the prostate. These portions of the Levatores ani, from the support 
they afford to the prostate, are named the Levator prostatae. 
The prostate consists of two lateral lobes and a middle lobe. 
The Lateral Lobes (lobus dexter st sinister).-The two lateral lobes are of 
equal size, separated by a deep notch above, and by a furrow upon the anterior 
and posterior surfaces of the gland, which indicates the bilobed condition of the 
organ in some animals. At the upper and posterior portion of the prostate the 
two lobes are united by two bands of gland-tissue. One of these bands is in front 
of the ejaculatory ducts, the other is below them. "The upper limit of the gland 
is thus in the form of a horseshoe, open in front."2 Below the level of the prostatic 
ducts the prostate and urethra are in relation, but are not closely connected. 
Above this level the connection is intimate (J. W. Thomson Walker). 
The So-called Middle Lobe (lobus medius).-The middle lobe is not in reality a 
lobe, and the name is usually employed to describe an enlargement of the region of 
the prostate on the posterior portion of the urethra in front of the ejaculatory ducts. 
The so-called third or middle lobe is an abnormal condition. It is due to enlargement 
of the transverse band of prostatic tissue which joins the lateral lobes beneath the 
1 W. G. Richardson on the Development and Anatomy of the Prostate Gland. 
2 J. W. Thomson Walker, in the British Medical Journal, July 9, 1904. 1452 
THE MALE ORGANS OF GENERATION 
base of the bladder, behind the posterior wall of the urethra and in front of the e jacu- 
latory ducts. This mass of tissue is beneath the uvula vesicae. Walker points out 
that frequently nodules of enlarged prostate protrude into the bladder,being covered 
only by bladder mucous membrane. This is accomplished by the enlarging pros- 
tate forcing its way through the lumen of the vesical sphincter and dilating it, 
and separating and passing between the strands of tne internal longitudinal 
muscle of the bladder. " The so-called middle lobe is formed by the protrusion of 
a nodule between the two bands of muscle which pass into the trigone from the 
ureters, and unite on the posterior wall of the prostatic urethra."1 
The urethra passes forward between the lateral lobes of the prostate. The 
prostate is perforated by the ejaculatory ducts. The urethra usually lies on the 
level of the junction of the anterior and middle thirds of a lateral lobe. The 
ejaculatory ducts pass obliquely downward and forward through the posterior 
part of the prostate, and open into the prostatic portion of the urethra. 
Structure (Fig. 1057).-As previously stated (p. 1449), the prostate is surrounded 
by a sheath from the recto-vesical fascia, and possesses also a true capsule. 
The glands of the prostate are of the branched tubular variety and number 
forty or fifty. Many of the ducts join and form from fifteen to twenty-five smaller 
ducts, which empty into the prostatic urethra, to the sides of the verumontanum 
(Fig. 1056). 'fhe ducts and glands are lined with cubical epithelium. The 
prostatic secretion or prostatic fluid (succus prostaticus) is a viscid, opalescent, 
serous secretion, alkaline in reaction, containing a ferment, but no mucus. The 
substance of the prostate is of a pale, reddish-gray color, of great density and 
not easily torn. It consists of glandular substance and muscular tissue. 
The muscular tissue, according to Kolliker, constitutes the proper stroma of 
the prostate, the connective tissue being very scanty, and simply forming thin 
trabeculae between the muscular fibres, in which the vessels and nerves of the 
gland ramify. The true capsule is continuous with the stroma. 'Fhe stroma lies 
between the glandular substance and strands of stroma pass in convergent lines 
toward the prostatic urethra, especially toward the dorsum of the urethra. These 
strands or septa divide the prostate into small irregular subdivisions called lobules. 
Next to the urethra, the stroma forms a thick layer. As age advances the inter- 
stitial tissue of the prostate increases and the glandular substance shrinks. 
Vessels and Nerves.-The arteries supplying the prostate are derived from the 
internal pudic, inferior vesical, and middle haemorrhoidal. Branches of the vessels 
enter the gland in the septa between the lobules and send off minute branches to the 
lobules (Walker). 'Fhe veins form a plexus around the sides and base of the gland 
between layers of the fascial sheath; they receive in front the dorsal vein of the 
penis, and terminate in the internal iliac vein. The lymphatics of the prostate 
begin as networks about the acini of the gland, pass to beneath the capsule, and 
form another network, and from this peripheral network collecting trunks arise. 
Several trunks pass from the posterior portion of the gland. One trunk passes to 
the external iliac glands, one to the internal iliac glands, and several end in the 
lateral sacral glands, and the glands of the sacral promontory. An anterior trunk 
is joined by lymphatics from the membranous urethra and prostatic urethra and 
passes to a gland on the internal pudic artery.2 'Fhe nerves are derived from the 
hypogastric plexus. 
Surgical Anatomy.-The relation oj the prostate to the rectum should be noted: by means of 
the finger introduced into the gut the surgeon detects enlargement or other disease of the prostate; 
he can feel the apex of the gland, which is the guide to Cock's operation for stricture; he is enabled 
also by the same means to direct the point of a catheter when its introduction is attended with 
difficulty either from injury or disease of the membranous or prostatic portions of the urethra. 
When the finger is introduced into the bowel the surgeon may, in some cases, especially in boys, 
1 J. W. Thomson Walker, in the British Medical Journal, July 9, 1904. 
- Poirier and Charpy. Human Anatomy. THE PENIS 
1453 
learn the position, as well as the size and weight, of a calculus in the bladder. In the operation 
for the removal of a calculus, if, as is not unfrequently the case, the stone should be lodged 
behind an enlarged prostate, it may be displaced from its position by pressing upward the base 
of the bladder from the rectum. The prostate gland is occasionally the seat of suppuration, either 
due to injury, gonorrhoea, or tuberculous disease. The gland is enveloped in a dense unyield- 
ing capsule, which determines the course of an abscess, and also explains the great pain which is 
present in acute inflammation. The abscess most frequently bursts into the urethra, the direc- 
tion in which there is least resistance, but may occasionally burst into the rectum, or more rarely 
in the perinaeum. In advanced life the prostate often becomes considerably enlarged, and may 
project into the bladder so as to impede the passage of the urine. According to Dr. Messer's 
researches, conducted at Greenwich Hospital, it would seem that such obstruction exists in 20 
per cent, of all men over sixty years of age. The prostate may be enlarged by the growth of 
innocent tumors, adenomata, fibromata, myomata, and myofibromata. The entire gland may 
be hypertrophied. A tumor may be encapsulated, but often is surrounded by an area of hyper- 
plasia of prostatic tissues, and usually the area of hyperplasia is much more extensive than the 
tumor. A tumor may be beneath the mucous membrane, deep in the gland, or beneath the 
sheath. The growth called the third lobe is submucous. In some cases the enlargement affects 
principally the lateral lobes, which may undergo considerable enlargement w ithout causing much 
inconvenience. In other cases it would seem that the nodule forms the so-called middle lobe, 
and even a small enlargement of this character may act injuriously, by forming a sort of valve 
over the urethral orifice, preventing the passage of the urine, and the more the patient strains, 
the more completely will it block the opening into the urethra. In consequence of the enlarge- 
ment of the prostate a pouch is formed at the base of the bladder behind the projection, in which 
urine collects and cannot entirely be expelled. The urine becomes decomposed and ammoniacal, 
and leads to cystitis. If the prostate enlarges the urethra is lengthened, often dilated, altered 
in shape, or distorted. 
The relation of the enlarged prostate to the neck of the bladder is greatly altered from the 
relation of the normal prostate. Normally, it is extra vesical; when enlarged it may encapsule 
''the neck of the bladder in a cuff-like manner, extending several inches upward on its wall," 
and often it protrudes " into the vesical cavity, carrying on its surface the mucosa vesicae."1 In 
many cases of prostatic enlargement the gland should be removed (prostatectomy'). One method 
is enucleation through a suprapubic incision; another method is enucleation through a perineal 
incision; another method is carried out by both incisions (the combined method). 
The Bottini operation is prostatotomy, effected by a special instrument for the purpose of 
cauterizing the gland and thus causing shrinking. 
In elderly individuals the gland tubules may form round, indurated, and sometimes calcified 
masses, about 1 mm. in diameter, and called prostatic stones. 
COWPER'S GLANDS (GLANDULAE BULBO-URETHRALES) 
(Figs. 1056, 1063). 
Cowper's glands are two small, rounded, and somewhat lobulated bodies of 
a yellow color, about the size of peas, placed behind the forepart of the mem- 
branous portion of the urethra, between the two layers of the triangular ligament. 
They lie close above the bulb, and are enclosed by the transverse fibres of the 
Compressor urethrae muscle. Their existence is said to be constant; they gradually 
diminish in size as age advances. 
Structure.-Each gland consists of several lobules held together by a fibrous 
investment. Each lobule consists of a number of acini lined by columnar epithe- 
lial cells, opening into one duct, which, joining with the ducts of other lobules 
outside the gland, form a single excretory duct (ductus excretorius}. The excretory 
duct of each gland, nearly an inch in length, passes obliquely forward beneath 
the mucous membrane, and opens by a minute orifice on the floor of the bulbous 
portion of the urethra. 
THE PENIS (Figs. 1058, 1059, 1060, 1061, 1062, 1063). 
The penis is a long body of prismatic shape placed below and in front of the 
symphysis pubis. It surrounds the greatest length of the urethra. It consists 
of a root, body, and extremity or glans penis. The root and the posterior portion 
1 John B. Murphy, in the Journal of the American Medical Association, May 28, 1904. THE MALE ORGANS OF GENERATION 
1454 
of the body lie beneath the scrotum and the integument of the perinseum (Fig. 
1054), and are firmly fixed to the triangular ligament, the pubic bones, and the 
symphysis; hence this portion of the organ 
is called the fixed portion (pars fixa) (Fig. 
309). The balance of the organ is free 
MEATUS 
MEDIAN GROOVE 
FOSSA OF 
FRAENUM 
FRAENUM 
CORONA 
NECK 
PREPUCE 
RETRACTED. 
Fig. 1058.-The penis, proximal portion, seen 
from below. (Testut.) 
Fig. 1059.-Glans penis, under surface. (Testut.) 
and movable (Fig. 1054), and is called the mobile portion (pars mobilis). When 
the penis is relaxed there is an angle between the fixed and mobile portions; 
when the penis is erect, the angle disappears. 
The Root (radix penis).-The root is firmly connected to the rami of the os 
pubis and ischium by two strong tapering, fibrous processes, the crura (Figs. 1058, 
1062, and 1063), and to the front of the symphysis pubis by the suspensory liga- 
ment (Fig.1061), a strong band 
of fibrous tissue which passes 
downward from the front of 
the symphysis pubis to the root 
of the penis. 
The extremity, acorn or 
glans penis (Figs. 1059 and 
1060) presents the form of an 
obtuse cone, flattened from 
above downward. At its sum- 
mit is a vertical fissure, the ex- 
ternal orifice of the urethra or 
the meatus urinarius (orificium 
urethrae externum). The base 
of the glans forms a rounded 
projecting border, the corona 
glandis, and behind the corona 
is a deep constriction, the cer- 
vix or neck (collum glandis). 
Upon both the corona and neck 
numerous small sebaceous 
glands are found, the glandulae 
Tysonii odoriferae.1 They secrete a sebaceous matter of very peculiar odor, which 
probably contains caseine and becomes easily decomposed. 
MEATUS 
DISTAL PART OF SEP- 
TUM PECTIN IFORME" 
/OSSA NAVIC- 
U LARIS 
G LA N S. 
PENIS 
FRENUM 
VALVE OF LA- 
CUNA MAGNA 
LEFT SIDE OF URETHRA 
FLOOR OF URETHRA 
LACUNA MAGNA 
PREPUCE 
RETRACTED 
SKIN 
DORSAL 
VEIN 
CORPUS 
CAVERNOSUM 
CORPUS 
SPONGIOSU M 
Fig. 1060.-The penis, distal end, in sagittal section one-twelfth inch 
at left of middle line. (Testut ) 
1 Stieda (Comptes-rendus du XII. Congrts International de Medecine, Moscow. 1897) asserts that Tyson's 
glands are never found on the corona glandis, and that what have hitherto been mistaken for glands are really 
large papillae. -Ed. of 15th English edition. THE PENIS 
1455 
The Body of the Penis (corpus penis).-The body of the penis is the part 
between the root and extremity. In the flaccid condition of the organ it is cylin- 
drical, but when erect it has a triangular prismatic form with rounded angles, the 
broadest side being turned upward, and called the dorsum penn,. The lower sur- 
face of the body of the penis is called the urethral surface (facies urethralis). The 
body is covered by integument, and contains in its interior a large portion of the 
urethra. The integument covering the penis is remarkable for its thinness, its 
dark color, its looseness of connection with the deeper parts of the organ, and for 
the absence of adipose tissue. At the root of the penis the integument is contin- 
uous with that upon the pubes and scrotum, and at the neck of the glans it leaves 
the surface and becomes folded upon itself to form the prepuce (praeputium) (Fig. 
1059). The internal layer of the prepuce is attached behind to the cervix or neck 
(Fig. 1059), and approaches in character to a mucous membrane; from the cervix 
it is reflected over the glans penis, and at the meatus urinarius is continuous with 
the mucous lining of the urethra. 
The integument covering the glans penis contains no sebaceous glands, but 
projecting from its free surface are a number of small, highly sensitive papillae. 
PERITONEUM 
SUPERFICIAL 
FIBRES OF 
SUSPENSORY 
LIGAMENT 
BLADDER 
DEEP FIBRES 
OF SUSPENSORY 
PUBIS 
LIGAMENT 
DORSAL VEIN 
ANTERIOR 
LIGAMENT 
OF BLADDER 
DORSAL ARTERY 
DORSAL NERVE 
SUBPUBIC 
LIGAMENT 
1 ERECTA PEN IS 
) MUSCLE 
Fig. 1061.-The suspensory ligament. (Poirier and Charpy.) 
At the back part of the meatus urinarius a fold of mucous membrane passes 
backward to the bottom of a depressed raphe, where it is continuous with the 
prepuce; this fold is termed the fraenum (frenulum praeputii). The skin of the penis 
covers the mobile parts of the organ. It is thin, extremely elastic, and contains very 
few hairs. Beneath the skin of the penis is the dartos layer (Figs. 1061 and 1068), 
continuous with the scrotal dartos, containing chiefly non-striated muscular fibres 
arranged longitudinally. It passes forward to the orifice of the prepuce, and 
then turns backward, growing thinner and thinner, and finally disappearing at 
the cervix. Beneath the dartos and extending forward to the orifice of the pre- 
puce is a sheath of areolar tissue. It is a lax sheath rich in elastic tissue and 
containing almost no fat. The superficial vessels and nerves are in the areolar 
sheath. Beneath the areolar sheath of the penis, from the corona to the root, is 
the fascia of the penis (fascia penis) (Fig. 1068). It covers the organ from the root 
to the corona, and also covers the dorsal artery, veins, and nerves. It is continuous 
behind with the superficial perineal fascia and suspensory ligament. It is com- 
posed chiefly of elastic tissue. 
Structure of the Penis.-The penis is composed of a mass of erectile tissue 
enclosed in three cylindrical fibrous compartments. Of these, two, the corpora THE MALE ORGANS OF GENERATION 
1456 
cavernosa, are placed side by side along the upper part of the organ; the third, or 
corpus spongiosum, encloses the urethra and is placed below. 
The Two Corpora Cavernosa (corpora cavernosa pcnisYVxgs. 1062 and 1063).-The 
two corpora cavernosa form the chief part of the body of the penis. They consist of 
two fibrous cylindrical tubes, placed side by side, and intimately connected along 
the median line for their anterior three- 
fourths, whilst at their back part they 
separate from each other to form the 
crura penis, which are two strong taper- 
ing fibrous processes or roots firmly 
connected to the rami of the os pubis 
and ischium (Figs. 1058, 1062, and 
1063). Each crus commences by a 
VAS 
DEFERENS 
SEMINAL 
VESICLE 
CORON A_ 
GLANDIS 
COWPER'S 
glands' 
MEMBRANOUS 
PORTION OF 
URETH RA 
CORONA 
GLANDIS 
BULB OF 
URETHRA 
EXTERNAL ORIFICE 
OF URETHRA 
Fig. 1062.-The penis, with the pubic bones, seen 
from before and below. (Toldt.) 
Fig.1063.-The penis, with the urethra, Cowper s 
glands, the prostate gland,and the seminal vesicles, 
seen from below and behind. (Toldt). THE PENIS 
1457 
blunt-pointed process in front of the tuberosity of the ischium, and before its junc- 
tion with its fellow to form the body of the penis it presents a slight enlargement, 
named by Kobelt the bulb of the corpus cavernosum. Just beyond this point they 
become constricted, and retain an equal diameter to their anterior extremity, where 
they form a single rounded end which is received into a fossa in the base of the glans 
penis (Figs. 1060 and 1062). A median groove on the upper surface lodges the 
dorsal arteries, nerves, and veins of the penis (Figs. 1066, 1067, and 1068), and the 
groove on the undersurface receives the corpus spongiosum (Fig. 1062). The root 
of the penis is connected to the symphysis pubis by the suspensory ligament. 
Structure (Fig. 1068).-Each corpus cavernosum is composed of erectile tissue. 
The erectile tissue is surrounded by a strong fibrous envelope, the tunica albuginea, 
corporum cavernosum, consisting of two sets of fibres-the one, longitudinal in direc- 
tion, being common to the two corpora cavernosa, and investing them in a com- 
mon covering; the other, internal, circular in direction, and being proper to each 
corpus cavernosum. The internal circular fibres of the two corpora cavernosa 
form, by their junction in the mesial plane, an incomplete partition or septum, 
the septum penis, between the two bodies. 
SUSPENSORY 
LIGAMENT" 
DARTOS- 
SAC OF. 
DARTOS/ 
SEPTUM- 
SCROTUM 
RAPHE* 
Fig. 1065.-From the peripheral portion of the corpus 
cavernosum penis under a low magnifying power. 1, a, 
capillary network; b, cavernous spaces; 2, connection of 
the arterial twigs (a) with the cavernous spaces. (Copied 
from Langer.) 
Fig. 1064.-The dartos. (Poirier and Charpy.) 
The septum between the two corpora cavernosa is thick and complete behind, 
but in front it is incomplete, and consists of a number of vertical bands, which are 
arranged like the teeth of a comb, whence the name which it has received, septum 
pectiniforme. These bands extend between the dorsal and the urethral surface 
of the corpora cavernosa. The fibrous investment of the corpora cavernosa is 
extremely dense, of considerable thickness, and consists of bundles of shining 
white fibres, with an admixture of well-developed elastic fibres, so that it is pos- 
sessed of great elasticity. 
From the internal surface of the fibrous envelope, as well as from the sides of 
the septum, are given off a number of bands or cords which cross the interior of 
each crus in all directions, subdividing it into a number of separate compart- 1458 
THE MALE ORGANS OF GENERATION 
ments, and giving the entire structure a spongy appearance. These bands and 
cords are called trabeculae corporum cavernosum, and consist of white fibrous 
tissue, elastic fibres, and plain muscular fibres. In them are continued numer- 
ous arteries and nerves. 
The component fibres of which the trabeculae are composed are larger and 
stronger around the circumference than at the centre of the corpora cavernosa; 
they are also thicker behind than in front. The interspaces, on the contrary, are 
larger at the centre than at the circumference, their long diameter being directed 
transversely; they are largest anteriorly. They are called cavernous spaces and 
are occupied by venous blood, and are lined by a layer of flattened cells similar 
to the endothelial lining of veins (Fig. 1065). 
The whole of the structure of the corpora cavernosa contained within the 
fibrous sheath consists, therefore, of a sponge-like tissue the areolar spaces of 
which freely communicate with each other and are filled with venous blood. 
The spaces may therefore be regarded as large cavernous veins. 
The arteries bringing the blood to these spaces are the arteries of the corpora 
cavernosa and branches from the dorsal artery of the penis, which perforate the 
fibrous capsule, along the upper surface, especially near the forepart of the organ. 
These arteries on entering the cavernous structure divide into branches which 
are supported and enclosed by the trabeculae. Some of these terminate in a 
capillary network, the branches of which open directly into the cavernous spaces 
(Fig. 1065); others assume a tendril-like appearance, and form convoluted and 
somewhat dilated vessels, which were named by Muller helicine arteries {arteriae 
helicinae). They project into the spaces, and from them are given off small 
capillary branches to supply the trabecular structure. They are bound down in 
the spaces by fine fibrous processes, and are more abundant in the back part of the 
corpora cavernosa. 
The blood from the cavernous spaces is returned by a series of vessels, some of 
which emerge in considerable numbers from the base of the glans penis and con- 
verge on the dorsum of the organ to form the deep dorsal vein; others pass out on the 
upper surface of the corpora cavernosa and join the dorsal vein; some emerge from 
the under surface of the corpora cavernosa,and, receiving branches from the corpus 
spongiosum, wind around the sides of the penis to terminate in the dorsal vein; 
but the greater number pass out at the root of the penis and join the prostatic plexus. 
The Corpus Spongiosum {corpus cavernosum urethrae') (Figs. 1060, 1062, and 
1063).-The corpus spongiosum encloses the urethra, and is situated in the groove 
on the under surface of the corpora cavernosa penis. It commences posteriorly 
below the superficial layer of the triangular ligament of the urethra, between 
the diverging crura of the corpora cavernosa, where it forms a rounded enlarge- 
ment, the bulb of the urethra {bulbus urethrae), and terminates anteriorly in another 
expansion, the glans penis (Figs. 1059, 1060, 10(12, and 1063), which overlaps the 
anterior rounded extremity of the corpora cavernosa. The central portion, or body 
of the corpus spongiosum, is cylindrical, and tapers slightly from behind forward. 
The Bulb of the Urethra (Figs. 1058, 1062, and 1063) varies in size in different 
subjects; it receives a fibrous investment from the superficial layer of the triangular 
ligament, and is surrounded by the Accelerator urinae muscle. The urethra enters 
the bulb nearer its upper than its lower surface, being surrounded by a layer of 
erectile tissue, a thin prolongation of which is continued backward around the 
membranous and prostatic portions of the canal to the neck of the bladder, lying 
between the two layers of muscular tissue. The portion of the bulb below the 
urethra presents a partial division into two lobes (hemisphaeria bulbi urethrae), 
being marked externally by a linear raph£, whilst internally there projects, for a 
short distance, a thin fibrous median septum {septum bulbi urethrae), which is more 
distinct in earlv life. THE PENIS 
1459 
Structure.-The corpus spongiosum consists of a strong fibrous envelope 
enclosing a trabecular structure, which contains in its meshes erectile tissue. The 
fibrous envelope is thinner, whiter in color, and more elastic than that of the corpora 
CAVERNOUS 
BRANCH 
DORSAL ARTERY 
CORPUS CAVERNOSUM 
GLANS PENIS 
-BULB 
ANTERIOR 
BRANCH 
CORPUS SPONGIOSUM 
IBULBOUS 
BRANCH 
INTERNAL PUDIC 
ARTERY 
Fig. 1066.-Diagram of the arteries of the penis. (Testut.) 
cavernosa of the penis. The trabeculae are more delicate, more nearly uniform 
in size, and the meshes between them smaller than in the corpora cavernosa, 
their long diameter, for the most part, corresponding with that of the penis. 
The external envelope or outer coat of the corpus spongiosum is formed partly 
of unstriped muscular fibre, and a 
layer of the same tissue immediately 
surrounds the canal of the urethra. 
Ligaments of the Penis.-The sus- 
pensory ligament (Jigamentum sus- 
pensorium penis} (Fig. 1061) is firm 
and fibrous. It passes from the front 
of the symphysis pubis to the tunica 
albuguinea of the corpora cavernosa. 
The ligamentum fundiforme penis 
(Fig. 1058), formerly called the sus- 
pensory ligament, arises from the 
linea alba, sheath of the rectus, 
superficial fascia, and symphysis 
pubis, and surrounds the penis in 
a loop, being attached more distal- 
ward than is the suspensory liga- 
ment, and usually passes into the 
scrotum. It is composed of elastic 
tissue. 
Vessels and Nerves of the Penis.- 
The arteries (Fig. 1066) of the penis 
come from branches of the internal 
pudic artery. The deep arteries of 
the penis give the chief supply to 
the erectile tissue of the corpora 
cavernosa, and the dorsal artery also 
sends branches to it; the artery of 
the bulb (p. 691) supplies the erectile 
tissue of the corpus spongiosum. The chief blood-supply of the glans is from 
the dorsal artery (p. 692). In the trabeculae the arteries are very small and often 
twisted. The twisted vessels are called helicine arteries. The small arteries 
open directly into the venous spaces. The veins of the penis empty directly into 
-SUPERFICIAL DORSAL VEIN 
EXTERNAL PUDIC VEIN 
OBTURATOR VEIN 
OS PUBIS 
Fig. 1067.-Veins of the penis. 
(Testut.) 1460 
THE MALE ORGANS OF GENERATION 
the prostatic plexus or into the deep dorsal vein, which empties into the prostatic 
plexus. On each side of the deep dorsal vein is a dorsal artery and external 
to each dorsal artery is a dorsal nerve (Fig. 1068). The superficial dorsal vein 
(Figs. 1067 and 1068), receiving small veins from the prepuce, passes back 
beneath the skin, reaches the symphysis and divides into two branches, each of 
which passes to the corresponding superficial external pudic vein. 
The lymphatics of this region have been studied carefully by Poirier, Cuneo, 
and Delamare,1 which book I have freely used. 
The lymphatics of the skin of the penis and prepuce are continuous (Fig. 501). 
Those on the internal surface of the prepuce are continuous with those of the glans. 
The trunks of the cutaneous lymphatics anastomose with each other, ascend by 
the dorsal vein, and terminate in the inguinal glands. The trunks from the glans 
converge toward the fraenum ; they 
then ascend to the median part of 
the corona, and the vessels of the two 
sides unite. Several collectors as- 
cend on the dorsum to the inguinal 
and femoral glands. 
The superior wall of the anterior 
portion of the urethra is drained by 
the lymphatic trunks from the glans. 
From the rest of the penile urethra 
the lymphatics unite with the trunks 
from the penis, and most of them ter- 
minate in the same way, although 
one of them passes between the 
Recti muscles and terminates in the deeper external iliac glands or in the 
"internal retro-crural gland."2 
The trunks from the bulb and membranous urethra terminate in the external 
iliac glands, the "internal retro-crural gland," and the glands along the internal 
pudic artery (Poirier, Cuneo, and Delamare). The trunks from the prostatic 
urethra join the trunks from the prostate gland. 
The nerves are derived from the internal pudic nerve and the pelvic plexus. On 
the glans and bulb some filaments of the cutaneous nerves have Pacinian bodies 
connected with them, and, according to Krause, many of them terminate in a 
peculiar form of end-bulb. 
SUPERFICIAL DOR- 
SAL VEIN 
CORPUS CAVER NOSUM. 
DORSAL ARTERY 
.DEEP DORSAL VEIN 
SUPERFICIAL 
FASCIA 
SKIN- 
AREOLAR 
' TISSUE 
CAVERNOUS. 
ARTERY 
DEEP 
FASCIA 
BULBO-CAVERNOUS ARTERY; 
- ANTERIOR BRANCH 
CORPUS 
SPONGIOSUM 
URETHRA 
Fig. 1068.-The penis in transverse section, showing 
the blood-vessels. (Testut.) 
Surgical Anatomy.-It is occasionally necessary to remove a penis for malignant disease. 
Usually, removal of the ante-scrotal portion is all that is necessary, but sometimes it is requisite 
to remove the whole organ from its attachment to the rami of the ossa pubis and ischia. The 
former operation is performed either by cutting off the whole of the anterior part of the penis 
with one sweep of the knife, or, what is better, cutting through the corpora cavernosa from the 
dorsum, and then separating the corpus spongiosum from them, dividing it at a level nearer the 
glans penis. The mucous membrane of the urethra is then slit up, and the edges of the flap 
attached to the external skin, in order to prevent contraction of the orifice, which would other- 
wise take place. The vessels which require ligature are the two dorsal arteries of the penis, the 
arteries of the corpora cavernosa, and the artery of the septum. When the entire organ requires 
removal the patient is placed in the lithotomy position, and an incision is made through the 
skin and subcutaneous tissue around the root of the penis, and carried down the median line of 
the scrotum as far as the perimeum. The two halves of the scrotum are then separated from 
each other, and a catheter having been introduced into the bladder as a guide, the spongy por- 
tion of the urethra below the triangular ligament is separated from the corpora cavernosa and 
divided, the catheter having been withdrawn just behind the bulb. The suspensory ligament 
is now severed, and the crura separated from the bone with a periosteum scraper, and the whole 
penis removed. The membranous portion of the urethra, which has not been removed, is now 
to be attached to the skin at the posterior extremity of the incision in the perimeum. The 
remainder of the wound is to be brought together, free drainage being provided for. 
1 Translated and edited by Cecil H. Leaf. 
2 The Lymphatics. By Poirier, Cuneo, and Delamare. Translated and edited by Cecil H. Leaf. DESCENT OF THE TESTIS 
1461 
THE TESTICLES (TESTES) AND THEIR COVERINGS (Figs. 1071, 1072). 
The testicles are two glandular organs, which secrete the semen; they are situ- 
ated in the scrotum, being suspended by the spermatic cords. At an early period 
of foetal life the testes are contained in the abdominal cavity, behind the peri- 
toneum, but they subsequently descend into the scrotum. 
DESCENT OF THE TESTIS (DESCENDUS TESTIS). 
Each testis at an early period of foetal life is placed at the back part of the 
abdominal cavity, behind the peritoneum, in front and a little below the kidney. 
The anterior surface and sides are invested by peritoneum. At about the third 
month of intra-uterine life a peculiar structure, the gubernaculum testis, makes its 
appearance. This structure is at first a slender band which extends from the 
situation of the internal ring to the epididymis and body of the testicle, and is 
then continued upward in front of the kidney toward the Diaphragm. As devel- 
opment advances the peritoneum covering the testicle encloses it and forms a 
mesentery, the mesorchium, which also encloses the gubernaculum and forms two 
folds-one above the testicle, and the other below it. The one above the testicle is 
•CREMASTER 
VAGINA 
EPIDIDYMIS 
-FIBROUS 
TUNIC 
HYDATID 
DARTOS 
ANASTOMOSIS 
'of VEINS 
Fig. 1069.-Vaginal tunics of the testicle. 
(Poirier and Charpy,) 
Fig. 1070.-Ligament of the scrotum. 
(Poirier and Charpy.) 
the plica vascularis, and contains ultimately the spermatic vessels; the one below, 
the plica gubernatrix, contains the lower part of the gubernaculum, which has now 
grown into a thick cord; it terminates below at the internal ring in a tube of peri- 
toneum, the processus vaginalis, which now lies in the inguinal canal. The lower 
part of the gubernaculum by the fifth month has become a thick cord, whilst the 
upper part has disappeared. The lower part can now be seen to consist of a cen- 
tral core of unstriped muscle-fibre, and outside this of a firm layer of striped 
elements, connected, behind the peritoneum, with the abdominal wall. Later on, 
about the sixth month, the lower end of the gubernaculum can be traced into the 
inguinal canal, extending to the pubes, and, at a later period, to the bottom of 
the scrotum. The fold of peritoneum constituting the processus vaginalis pro- 
jects itself downward into the inguinal canal, forming a gradually elongating 
depression or cul-de-sac, which eventually reaches the bottom of the scrotum. This 
cul-de-sac is now invaginated by the testicle, as the body of the foetus grows, for the 
gubernaculum does not grow commensurately with the growth of other parts, and 
therefore the testicle, being attached by the gubernaculum to the bottom of the THE MALE ORGANS OF GENERATION 
1462 
scrotum, is prevented from rising as the body grows, and is drawn first into the 
inguinal canal, and eventually into the scrotum. By the eighth month the tes- 
ticle has reached the scrotum, preceded by the lengthened pouch of peritoneum, 
the processus vaginalis, which communicates by its upper extremity with the 
peritoneal cavity. Just before birth the upper part of the pouch usually becomes 
closed, and this obliteration extends gradually downward to within a short dis- 
tance of the testis. The process of peritoneum surrounding the testis, which is now 
entirely cut off from the general peritoneal cavity, constitutes the tunica vaginalis.1 
Mr. Jacobson2 says that the attachments of the gubernaculum above are to 
the vas, the epididymis, and afterward to the testicle. The lower attachments 
of the gubernaculum, some of which are temporary, are the abdominal wall, 
pubes and root of the scrotum, Scarpa's triangle, perinseum and scrotum. The 
remains of the scrotal fibres constitute a so-called ligament of the scrotum or 
the mesorchium, which causes adhesion between the testicle and skin (Fig. 1070). 
In the female, a small cord, corresponding to the gubernaculum in the male, 
descends to the inguinal region and ultimately forms the round ligament of the 
uterus. A pouch of peritoneum accompanies it along the inguinal canal, analogous 
to the processus vaginalis in the male; it is called the canal of Nuck. 
Surgical Anatomy.-Abnormalities in the formation and in the descent of the testicle may 
occur. The testicle may fail to be developed, or it may be fully developed and the vas deferens 
may be undeveloped in whole or in part; or, again, both testicle and vas deferens may be fully 
developed, but the duct may not become connected to the gland. The testicle may fail in its 
descent (cry ptorc hismus) or it may descend into some abnormal position (ectopia testis). Thus it 
may be retained in the position where it was primarily developed, below the kidney; or it may 
descend to the internal abdominal ring, but fail to pass through this opening; it may be retained 
in the inguinal canal, which is perhaps the most common position; or it may pass through the 
external abdominal ring and remain just outside it, failing to pass to the bottom of the scrotum. 
On the other hand, it may get into some abnormal position; it may pass the scrotum and reach 
the perinseum, or it may fail to enter the inguinal canal, and may find its way through the fem- 
oral ring into the crural canal, and present itself on the thigh at the saphenous opening. Ectopia 
testis is due to the absence, overdevelopment or malposition of some portion of the gubernacu- 
lum. There is still a third class of cases of abnormality in the position of the testicle, where the 
organ has descended in due course into the scrotum, but is malplaced. The most common form 
of this is where the testicle is inverted,••that is to say, the organ is rotated, so that the epididymis 
is connected to the front of the scrotum, and the body, surrounded by the tunica vaginalis, is 
directed backward. In these cases the vas deferens is to be felt in the front of the cord. The 
condition is of importance in connection with hydrocele and ha'inatocele, and the position of 
the testicle should always be carefully ascertained before performing any operation for these 
affections. Again, more rarely, the testicle may be reversed. This is a condition in which the 
top of the testicle, indicated by the globus major of the epididymis, is at the bottom of the 
scrotum, and the vas deferens comes off from the summit of the organ. 
THE COVERINGS OF THE TESTICLE (Fig. 1073). 
The coverings of the testicle are the following 
Skin 
Dart os 
Scrotum. 
Intercolumnar or External spermatic fascia. 
Cremasteric fascia. 
Infundibuliform or Fascia propria (Internal spermatic fascia). 
Tunica vaginalis. 
The Testicular Bag or Scrotum (Figs. 1071 and 1072).-The testicular bag or 
scrotum is a cutaneous pouch which contains the testes and part of the spermatic 
cords. It is divided on its surface into two lateral portions by a median line or 
1 The obliteration of the process of peritoneum which accompanies the cord, and is hence called the funicular 
process, is often incomplete. See section on Inguinal Hernia. 
2 Diseases of the Male Organs of Generation. THE COVERINGS OF THE TESTICLE 
1463 
raphd {raphe scroti), which is continued forward to the under surface of the penis 
and backward along the middle line of the perinseum to the anus. Of these two 
lateral portions, the left is usually longer than the right, and corresponds with the 
usual greater length of the spermatic cord on the left side. Its external aspect varies 
under different circumstances: thus under the influence of warmth and in old and 
debilitated persons it becomes elongated and flaccid, but under the influence of cold 
and in the young and robust it is short, corrugated, and closely applied to the 
testes. The wrinkles in the scrotum are called rugae. 
The scrotum consists of two layers, the integument and the dartos. 
RIGHT INGUINAL CANAL 
(opened) 
'persistent SEROUS 
CAVITY AROUND 
^CORD-EXCEPTIONAL 
CREMASTERIC MUSCLE- 
AND FASCIA 
INTERCOLUMNAR 
FASCIA 
TUNICA VAGINALIS- 
PARIETAL LAYER 
DARTOS 
INFUNDIBULIFORM 
FASCIA 
NON-PEDUNCULATED 
HYDATID 
RIGHT HALF OF SCROTUM SKIN 
LEFT* HALF OF SCROTUM 
Fig. 1071.-The scrotum. On the left side the cavity of the tunica vaginalis has been opened ; on the 
right side only the layers superficial to the cremaster have been removed. (Testut.) 
The Integument.-The integument is very thin, of a brownish color, and gen- 
erally thrown into folds or rugae. It is provided with sebaceous follicles, the 
secretion of which has a pecidiar odor, and is beset with thinly-scattered, crisp 
hairs, the roots of which are seen through the skin. 
The Daitos (tunica dartos) (Figs. 1064 and 1071).-The dartos is a thin layer of 
loose tissue, endowed with contractility; it forms the proper tunic of the scrotum, 
is continuous around the base of the scrotum, with the two layers of the super- 
ficial fascia of the groin and perinaeum, and sends inward a distinct septum, 
the septum of the scrotum (septum scroti) (Fig. 1071), which divides it into two 
cavities for the two testes, the septum extending between the raphe and the 
under surface of the penis as far as its root. 
The dartos is closely united to the skin externally, but connected with the 1464 
THE MALE ORGANS OE GENERATION 
subjacent parts by delicate areolar tissue, upon which it glides with the greatest 
facility. The dartos is very vascular, and consists of a loose areolar tissue con- 
taining unstriped muscular fibre, but no fat. Its contractibility is slow, and 
excited by cold and mechanical stimuli, but not by electricity. 
The Intercolumnar or Spermatic Fascia (Fig. 1071).-The intercolumnar 
fascia is a thin membrane derived from the margin of the pillars of the external 
abdominal ring, during the descent of the testis in the foetus, which is prolonged 
downward around the surface of the cord and testis. It is separated from the 
EXTERNAL 
ABDOMINAL- 
RING 
VAS 
DEFERENS 
SPERMATIC 
ARTERY 
ACCESSORY 
SLIP OF 
ORIGIN OF- 
CREMASTER 
MUSCLE 
SPERMATIC 
CORD 
-N ERVE-FI LAM E NTS 
OF SPERMATIC 
PLEXUS 
.DEFERENTIAL 
ARTERY 
IN FUN DIBULI FORM 
FASCIA 
CREMASTER^ 
MUSCLE 
PLEXUS 
EPIDIDYMIS 
SEPTUM OF. 
SCROTUM 
PARIETAL 
LAYER OF 
TUNICA 
VAGINALI 
DARTOS" 
RAPHE 
Fig. 1072.-The scrotum. The penis has been turned upward, and the anterior wall of the scrotum has been 
removed. On the right side, the spermatic cord, the infundibuliform fascia and the Cremaster muscle are dis- 
played; on the left side, the infundibuliform fascia has been divided by a longitudinal incision passing along the 
front of the cord and the testicle, and a portion of the parietal layer of the tunica vaginalis has been removed to 
display the testicle and a portion of the head of the epididymis, which are covered by the visceral layer of the 
tunica vaginalis. (Toldt.) 
dartos by loose areolar tissue, which allows of considerable movement of the 
latter upon it, but is intimately connected with the succeeding layers. 
The Cremasteric Fascia (fascia cremasterica) (Figs. 1071 and 1072).-The 
cremasteric fascia consists of scattered bundles of muscular fibres, the Cremaster 
muscle (m. cremaster) (Figs. 1071 and 1072) connected together into a continuous 
covering by intermediate areolar tissue. The muscular fibres are continuous 
with the lower border of the Internal oblique muscle. THE COVERINGS OF THE TESTICLE 
The Infundibuliform Fascia (. tunica vaginalis communis [testis et funiculi sper- 
matici]) (Figs. 1071 and 1071).-The infundibuliform fascia is a thin membranous 
1465 
Skin. 
Dartos. 
External spermatic fascia. 
Cremasteric fascia. 
Inf undibuliform fascia. 
Parietal tunica vaginalis. 
Visceral tunica vaginalis. 
Tunica vasculosa.. 
Tunica albuginea. 
A lobule of the testicle. 
A septum. 
Mediastinum. 
Digital fossa. 
Spermatic vein. 
Epididymis. 
Vas deferens. 
Artery to vas. 
Spermatic artery. 
Internal cremaster 
muscle. 
Fig. 1073.-Transverse section through the left side of the scrotum and the left testicle. The sac of the 
tunica vaginalis is represented in a distended condition. (Del6pine.) 
layer, which loosely invests the surface of the cord. It is a continuation downward 
of the fascia transversalis. Beneath it is a quantity of loose connective tissue which 
connects this layer of fascia with the spermatic cord and posterior parts of the tes- 
SPERMATIC 
ARTERY 
.CREMASTERIC 
ARTERY 
ANTERIOR 
GROUP OF 
VEINS 
DEFERENTIAL 
ARTERY 
SEMINAL 
DUCT 
POSTERIOR 
GROUP OF 
VEINS 
b ANASTOMOSIS 
OF VEINS 
Fig. 1074.- The arteries of the testicle and the cord. (Poirier and Charpy.) 
tide. This connective tissue is continuous above with the subserous areolar tissue of 
the abdomen. These two layers, the infundibuliform fascia and the tissue beneath 1466 
THE MALE ORGANS OF GENERATION 
it, are known collectively as the fascia propria. The infundibuliform fascia com- 
pletely encloses the testicle and epididymis and is fused with the parietal lamina 
of the tunica vaginalis propria testis. 
The Tunica Vaginalis (tunica vaginalis propria testis').-The tunica vagi- 
nalis is described with the testis (p. 1469.) 
Vessels and Nerves.-The arteries supplying the coverings of the testis are: 
the superficial and deep external pudic, from the femoral; the superficial perineal 
branch of the internal pudic; and the cremasteric branch from the deep epigastric. 
The veins follow the course of the corresponding arteries. The lymphatics term- 
inate in the inguinal glands. The nerves are: the ilio-inguinal branch of the 
lumbar plexus, the two superficial perineal branches of the internal pudic nerve, 
the inferior pudenal branch of the small sciatic nerve, and the genital branch of 
the genito-crural nerve. 
TRANSVE RSA LI S 
FASCIA 
DEEP 
EPIGASTRIC 
ARTERY 
LIGAMENT 
OF CLOQUET 
VAS 
DEFERENS 
SPERMATIC 
ARTERY 
SPERMATIC 
CORD 
Fig. 1075.-The spermatic cord and the ligament of Cloquet. (Poirier and Charpy.) 
PAMPINIFORM 
PLEXUS 
THE SPERMATIC CORD (FUNICULUS SPERM ATICUS; 
(Figs. 1071, 1072, 1075, 1076;. 
The spermatic cord extends from the internal abdominal ring, where the 
structures of which it is composed converge, to the back part of the testicle. In 
the abdominal wall the cord passes obliquely along the inguinal canal, lying at 
first beneath the Internal oblique muscle and upon the fascia transversalis; but 
nearer the pubes it rests upon Poupart's ligament, having the aponeurosis of 
the External oblique in front of it and the conjoined tendon behind it. It then 
escapes at the external ring, and descends nearly vertically into the scrotum. The 
left cord is usually rather longer than the right, consequently the left testis 
generally hangs somewhat lower than its fellow. 
Structure.-The spermatic cord contains the spermatic duct, the deferential 
artery and veins, the spermatic artery, the pampiniform plexus of veins, the sper- 
matic plexus, and the deferential plexus of the sympathetic nerve, lymphatics, and 
the cord-like remnant of the funicular process of peritoneum called the ligament THE SPERMATIC CORD 
1467 
of Cloquet (Fig. 1075). All the above structures are held together by connective 
tissue. These structures are ensheathed by the infundibuliform process of the trans- 
versalis fascia (tunica vaginalis communis [testis et funiculi spermatid]) (Fig. 1075 
and p. 1064). This fascia is thin above and thicker below, and encloses the testicle 
and epididymis, as well as the cord, being firmly adherent to the parietal layer of 
the vaginal tunic of the testicle and with the posterior portion of the testicle and 
epididymis. Upon this fascia are the fibres of the Cremaster muscle, which spring 
from the internal oblique, and in this fascia are the cremasteric artery, the genital 
branch of the genito-crural nerve, and external spermatic veins. This fascia is 
surrounded by the intercolumnar or spermatic fascia (fascia cremasterica [Cooperi]), 
which is distinct above, but not below. 
Vessels and Nerves of the Spermatic Cord.-The arteries (Figs. 1074 and 1080) of 
the cord are: the spermatic, from the aorta; the artery of the vas deferens, from 
the superior vesical; the cremasteric, from the deep epigastric. 
OBLIQUE 
MUSCLES 
VAS 
DEFERENS" 
SPERMATIC 
'cord 
APONEUROSIS 
OF EXTERNAL 
OBLIQUE MUSCLE 
INTERNAL 
SAPHENOUS 
VEIN 
The spermatic artery (a. spermatica interna) arises from the abdominal aorta 
below the renal artery, descends by the Psoas muscle, crosses the ureter and 
external iliac vessels, meets the vas deferens at the internal abdominal ring, 
escapes from the abdomen at the internal or deep abdominal ring, and lying in 
front of the vas deferens accompanies the other constituents of the spermatic cord 
along the inguinal canal and through the external abdominal ring into the scrotum. 
It then descends to the testicle, and, becoming tortuous, divides into several 
branches, two or three of which, the epididymal branches, accompany the vas 
deferens and supply the epididymis, anastomosing with the artery of the vas 
deferens and the cremasteric artery; others, the glandular branches, pierce the back 
of the tunica albuginea and supply the substance of the testis. 
The artery of the vas deferens, a branch of the superior vesical, is a long slender 
vessel which accompanies the vas deferens, ramifying upon the coats of that duct, 
and anastomosing with the spermatic artery and the cremasteric artery near the 
testis. 
Fig. 1076.-The spermatic cord in the inguinal canal. (Poirier and Charpy.) 1468 
THE MALE ORGANS OE GENERATION 
The cremasteric artery (a. spermatica externa) is a branch of the deep epigas- 
tric artery. It accompanies the spermatic cord and supplies the Cremaster 
muscle and other coverings of the cord, anastomosing with the spermatic and 
deferential arteries. 
The spermatic veins (Figs. 1074, 1075, 1076, and 1077) emerge from the back of 
the testis and receive tributaries from the epididymis; they unite and form a con- 
voluted plexus, the pampiniform plexus {plexus pampinijormis), which forms the 
chief mass of the cord; the vessels composing this plexus are very numerous, and 
ascend along the cord in front of the vas deferens; below the external or super- 
Fig. 1077.-Spermatic veins. (Testut.) 
ficial abdominal ring they unite to form three or four veins, which pass along the 
inguinal canal, and, entering the abdomen through the internal or deep abdominal 
ring, coalesce to form two veins. These again unite to form a single vein, which 
opens on the right side into the inferior vena cava at an acute angle, and on the 
left side into the renal vein at a right angle. 
The lymphatic vessels of the scrotum terminate in the superficial inguinal 
glands. The lymphatics of the testicle join the lymphatics of the epididymis and of 
the visceral layer of the vaginal tunic of the testicle, and ascend in the spermatic 
cord. They reach the lumbar region along the spermatic blood-vessels and ter- 
minate in the juxta-aorta glands, and sometimes in the glands in front of the 
aorta. The lymphatics of the seminal duct pass to the external iliac glands. THE TESTICLES 
1469 
The nerves are the spermatic plexus from the sympathetic, joined by filaments 
from the pelvic plexus which accompany the artery of the vas deferens. 
The Ligament of the Scrotum.-See Fig. 1070 and p. 1462. 
Surgical Anatomy.-The scrotum forms an admirable covering for the protection of the 
testicle. This body, lying suspended and loose in the cavity of the scrotum, and surrounded by 
a serous membrane, is capable of great mobility, and can therefore easily slip about within the 
scrotum, and thus avoid injuries from blows or squeezes. The skin of the scrotum is very 
elastic and capable of great distention, and on account of the looseness and amount of subcu- 
taneous tissue the scrotum becomes greatly enlarged in cases of (edema, to which this part is 
especially liable on account of its dependent position. The scrotum is frequently the seat of 
epithelioma; this is no doubt due to the rugae on its surface, which favor the lodgement of dirt, 
and this, causing irritation, is the exciting cause of the disease. Cancer was especially common 
in chimney-sweeps from the lodgement of soot. The scrotum is also the part most frequently 
affected by elephantiasis. 
On account of the looseness of the subcutaneous tissue considerable extravasations of blood 
may take place from very slight injuries. It is therefore generally recommended never to apply 
leeches to the scrotum, since they may lead to considerable ecchymosis, but rather to puncture 
one or more of the superficial veins of the scrotum in cases where local bloodletting from this 
part is judged to be desirable. The muscular fibre in the dartos causes contraction and consider- 
able diminution in the size of a wound of the scrotum, as after the operation of castration, and 
is of assistance in keeping the edges together and covering the exposed parts. 
THE TESTICLES (TESTES) (Figs. 1069, 1071, 1072, 1078, 1079). 
The testicles are suspended in the scrotum by the spermatic cords. As the left 
spermatic cord is rather longer than the right one, the left testicle hangs somewhat 
lower than its fellow. Each gland is of an oval form, compressed laterally, and 
having an oblique position in the scrotum, the upper extremity {extremities superior) 
being directed forward and a little outward, the lower extremity {extremitus infe- 
rior), backward and a little inward; the anterior convex border {margo anterior) 
looks forward and downward; the posterior or straight border {margo posterior), 
to which the cord is attached, backward and upward. 
The anterior border and lateral surfaces {facies lateralis et fecies medialis), as well 
as both extremities of the organ, are convex, free, smooth, and invested by the 
visceral layer of the tunica vaginalis. The posterior border, to which the cord is 
attached, receives only a partial investment from that membrane. Lying upon 
the outer edge of this posterior border is a long, narrow, flattened body, named, 
from its relation to the testis, the epididymis {didopot;, testis) (Figs. 1078 and 1079). 
The curve of the epididymis is convex outward and backward. It consists of 
a central portion or body {corpus epididymidis)-, an upper enlarged extremity, the 
head or globus major {caput epididymidis)-, and a lower pointed extremity, the tail 
or globus minor {cauda epididymidis). The globus major is directed inward and 
is intimately connected with the upper end of the testicle by means of its efferent 
ducts, and the globus minor is connected with its lower end by cellular tissue and a 
reflection of the tunica vaginalis. The globus minor bends suddenly and passes 
into the seminal duct, the direction of which is upward and backward. The outer 
surface and upper and lower ends of the epididymis are free and covered by 
serous membrane; the body is also completely invested by it, excepting along its 
posterior border, and between the body and the testicle is a pouch or cul-de-sac, 
•named the digital fossa {sinus epididymidis). Above this fossa is a fold of the 
tunica vaginalis, which is called the ligamentum epididymidis superior, and below 
it is another fold, the ligamentum epididymidis inferior. The epididymis is con- 
nected to the back of the testis by a fold of the serous membrane. Attached to 
the upper end of the testis, close to the globus major, is a small body. It is oblong 
in shape and has a broad base. Attached to the globus major of the epididymis 
is another small body, which is pear-shaped and has a stalk. These bodies are THE MALE ORGANS OF GENERATION 
1470 
believed to be the remains of the upper extremity of the Mullerian duct, and are 
termed the hydatids of Morgagni; some observers, however, regard the stalked 
hydatid as being a rudiment of the pronephros. The body with a broad base is 
the non-pedunculated hydatid {appendix testis [Morgagnii]) (Figs. 1071 and 1078); 
Spermatic cord. 
Artery of 
cord. 
SPERM. 
CORD 
'epi bib* 
MEDIASTINUM 
TESTIS 
Tunica vaginalis, 
parietal layer. ' 
Head. 
Non-pedunculated 
hydatid. 
Digital 
fossa. 
Testis. 
ALBUGINEA 
Fig. 1078.-The testis in situ, the tunica vaginalis 
having been laid open. 
Fig. 1079.-Frontal section of the testicle and 
epididymis. (Poirier and Charpy.) 
the pear-shaped body is the 
pedunculated hydatid (appendix 
epididymidis'). When the tes- 
ticle is removed from the body, 
the position of the vas deferens, 
on the posterior surface of the 
testicle and inner side of the 
epididymis, marks the side to 
which the gland has belonged. 
Size and Weight.-The aver- 
age dimensions of this gland 
are from one and a half to two 
inches in length, one inch in 
breadth, and an inch and a 
quarter in the antero-posterior 
diameter, and the weight varies 
from six to eight drachms, the 
left testicle being a little the 
larger. 
The Tunics of the Testicle. 
The testis is invested by three tu- 
nics-the tunica vaginalis, tunica 
albuginea, and tunica vasculosa. 
The Proper Sheath of the Testicle or the Tunica Vaginalis (tunica vaginalis propria 
testis) (Figs. 1069, 1071, 1072,1073, and 1080) is the serous covering of the testicle 
and epididymis. It is a pouch of serous membrane, derived from the peritoneum 
(processus vaginalis peritonaei) during the descent of the testis in the foetus from 
the abdomen into the scrotum. After its descent that portion of the pouch which 
Tunica Vaginalis. 
Tunica Albuginea. 
Its Septa. 
Ductuli 
~efferentes. 
Tubuli 
seminiferi- 
cantor ti. 
Tubuli 
.seminiferi 
recti. 
Fig. 1080.-Vertical section of the testicle, to show the arrange- 
ment of the ducts. THE TESTICLES 
1471 
extends from the internal ring to near the upper part of the gland, the funicular 
process, becomes obliterated, the lower portion remaining as a shut sac (tunica 
vaginalis propria testis), which invests the outer surface of the testis, and is reflected 
on to the internal surface of the scrotum; hence it may be described as consisting 
of a visceral and parietal portion. 
The Visceral Portion (lamina visceralis) of the tunica vaginalis propria covers 
the outer surface of the testis, as well as the epididymis, connecting the latter to 
the testis by means of a distinct fold. From the posterior border of the gland it 
is reflected on to the internal surface of the infundibuliform process of the trans- 
versalis fascia, and between the tunic and the fascia is a layer of unstriated 
muscle fibres, the Internal cremaster muscle (Fig. 1073). 
The Parietal Portion (lamina parietalis) of the tunica vaginalis propria is the 
reflected portion. It is far more extensive than the visceral portion, extending 
upward for some distance in front and on the inner side of the cord, and reaching 
below the testis. The inner surface of the tunica vaginalis is free, smooth, and 
covered by a layer of endothelial cells. The interval between the visceral and 
parietal layers of this membrane constitutes the cavity of the tunica vaginalis and 
contains a small amount of serous fluid. 
The obliterated portion of the pouch may generally be seen as a fibro-cellular 
thread, the ligament of Cloquet (rudimentum processus vaginalis) (Fig. 1075), lying in 
the loose areolar tissue around the spermatic cord; sometimes this may be traced 
as a distinct band from the upper end of the inguinal canal, where it is connected 
with the peritoneum, down to the tunica vaginalis; sometimes it gradually becomes 
lost on the spermatic cord. Occasionally no trace of it can be detected. In some 
cases it happens that the pouch of peritoneum does not become obliterated, but 
the sac of the peritoneum communicates with the tunica vaginalis. This may 
give rise to one of the varieties of oblique inguinal hernia; or in other cases the 
pouch may contract, but not become entirely obliterated; it then forms a minute 
canal leading from the peritoneum to the tunica vaginalis.1 
The Tunica Albuginea (Figs. 1073, 1079, and 1080).-The tunica albuginea is 
the fibrous covering of the testis. It is a dense fibrous membrane, of a bluish-white 
color, composed of bundles of white fibrous tissue, which interlace in every direc- 
tion. Its outer surface is covered by the tunica vaginalis, except at the points of 
attachment of the epididymis to the testicle, and along its posterior border, where 
the spermatic vessels enter the gland. This membrane surrounds the glandular 
structure of the testicle, and at its posterior border forms a projection, triangular 
in shape and cellular in structure, which is reflected into the interior of the gland, 
forming an incomplete vertical septum, called the mediastinum testis. 
The Mediastinum Testis (corpus Highmori) (Figs. 1073, 1079, and 1080) extends 
from the upper, nearly to the lower, extremity of the gland, and is wider above 
than below. From the front and sides of this septum numerous slender fibrous 
cords and imperfect septa, called the trabeculae (septula testis) (Fig. 1080), are 
given off, which radiate toward the surface of the organ, and are attached to the 
inner surface of the tunica albuginea. This scaffolding of connective tissue divides 
the parenchyma (parenchyma testis) of the organ into a number of incomplete 
spaces, which are somewhat cone-shaped, being broad at their bases at the sur- 
face of the gland, and becoming narrower as they converge to the mediastinum. 
The mediastinum supports the blood-vessels, lymphatics, and ducts of the testis 
in their passage to and from the substance of the gland, and contains numerous 
fine canals, into which open the very small tubules of the proper substance of 
the testicle. 
1 It is recorded that in the post-mortem examination of Sir Astley Cooper a minute funicular canal was found 
on each side of the body. Sir Astley Cooper states that when a student he suffered from inguinal hernia ; prob- 
ably this was of the congenital variety, and the canal found after death was the remains of the one down which 
the hernia travelled (Lancet, 1824, vol. ii. p. 116.).-Ed. of 15th English edition. THE MALE ORGANS OF GENERATION 
1472 
The Tunica Vasculosa (Fig. 1073).-The tunica vasculosa is the vascular layer of 
the testis, and consists of a plexus of blood-vessels held together by a delicate 
areolar tissue. It covers the inner surface of the tunica albuginea and the dif- 
ferent septa in the interior of the gland, and therefore forms an internal invest- 
ment to all the spaces of which the gland is composed. * 
Structure of the Testicle and Epididymis (Fig. 1080).-The glandular struc- 
ture of the testis consists of numerous lobules (lobuli testis). Their number, in a 
single testis, is estimated by Berres at 250, and by Krause at 400. They differ in size 
according to their position, those in the middle of the gland being larger and longer. 
The lobules are conical in shape, the base of each being directed toward the circum- 
ference of the organ, the apex toward the mediastinum. Each lobule is contained in 
one of the intervals between the fibrous cords and vascular processes which extend 
between the mediastinum testis and the tunica albuginea, and consists of from one 
to three or more minute convoluted tubes, which anastomose with each other, the 
tubuli seminiferi contorti. The contorted tubes unite at the apex of the lobules and 
form the straight tubes (tubuli seminiferi recti). The straight tubes pass into the 
mediastinum testis and form the network known as the rete testis of Haller (Fig. 
1080). The rete testis is lined with flattened epithelium. The tubes are lined with 
columnar ciliated epithelium. The efferent ducts (dwti efferentes testis) (Fig. 1080), 
about twelve to fifteen in number, arise from the rete. The contorted tubes may 
be separately unravelled by careful dissection under water, and may be seen to 
commence either by free caecal ends or by anastomotic loops. The total number of 
tubes is considered by Munro to be about 300 and the length of each about sixteen 
feet; by Lauth their number is estimated at 840, and their average length two feet 
and a quarter. The diameter varies from to yJ-p- of an inch. The tubuli are 
pale in color in early life, but in old age they acquire a deep-yellow tinge from 
containing much fatty matter. Each tube consists of a basement layer, formed 
of epithelioid cells united edge to edge, outside of which are other layers of 
flattened cells arranged in interrupted laminae, which give to the tube an appear- 
ance of striation in cross-section. The cells of the outer layers gradually pass 
into the interstitial tissue. Within the basement-membrane are epithelial cells 
arranged in several irregular layers, which are not always clearly separated, but 
which may be arranged in three different groups. Among these cells may be seen 
the spermatozoids in different stages of development. 1. Lining the basement- 
membrane and forming the outer zone is a layer of cubical cells, with small 
nuclei; these are known as the lining cells or spermatogonia. The nucleus of some 
of them may be seen to be in the process of indirect division (karyokinesis), and 
in consequence of this daughter cells are formed, which constitute the second zone. 
2. Within this first layer is to be seen a number of larger cells with clear nuclei, 
arranged in two or three layers; these are the intermediate cells or spermatocytes. 
Most of these cells are in a condition of karyokinetic division, and the cells which 
result from this division form those of the next layer, the spermatoblasts or sperma- 
tids. 3. The third layer of cells therefore consists of the spermatoblasts or sperma- 
tids, and each of these, without further subdivision, becomes a spermatozoid. They 
are ill-defined granular masses of protoplasm, of an elongated form, with a nucleus 
which becomes the head of the future spermatozoid. In addition to these three 
layers of cells others are seen, which are termed the supporting cells, or cells of 
Sertoli. They are elongated and columnar, and project inward from the basement- 
membrane toward the lumen of the tube. They give off numerous lateral branches, 
which form a reticulum for the support of the three groups of cells just described. 
As development of the spermatozoids proceeds the latter group themselves around 
the inner extremities of the supporting cells. The nuclear part of the sperma- 
tozoid, which is partly embedded in the supporting cell, is differentiated to form the 
head of the spermatozoid, while the cell protoplasm becomes lengthened out to THE TESTICLES 
1473 
form the middle piece and tail, the latter projecting into the lumen of the tube. 
Ultimately the heads are separated and the spermatozoids are set free. 
Spermatogenesis.-The stages in the development of the spermatozoids are as 
follows: The spermatogonia become enlarged to form the spermatocytes, and 
each spermatocyte subdivides into two cells, and each of these again divides into 
two spermatids or young spermatozoids, so that the spermatocyte gives origin to 
four spermatozoids. 
The process of spermatogenesis bears a close relation to that of maturation of 
the ovum. The spermatocyte is equivalent to the immature ovum. It undergoes 
subdivision, and ultimately gives origin to four spermatozoids, each of which con- 
tains, therefore, only one-fourth of the chromatin elements of the nucleus of the 
spermatocyte. In the process of maturation of the ovum its nucleus divides, one- 
half being extended as the first polar body. The remaining half of the nucleus 
again subdivides, one-half being extended as the second polar body. The portion 
of the nucleus which is retained to form the female pronucleus of the now matured 
ovum contains, therefore, only one-fourth of the chromatin elements of the 
original nucleus, and thus the spermatozoid and the matured ovum, so far as 
their nuclear elements are concerned, may be regarded as of the same morpho- 
logical value. 
The tubules are enclosed in a delicate plexus of capillary vessels, and are held 
together by an intertubular connective tissue, which presents large interstitial 
spaces lined by endothelium, which are believed to be the rootlets of lymphatic 
vessels of the testis. 
The Aberrant Ducts of the Epididymis (ductuli aberrantes) are tortuous and end 
in blind extremities. The superior aberrant duct (ductus aberrans superior) is in the 
globus major and joins the rete testis. The inferior aberrant duct (ductus aberrans 
inferior) (Fig. 1080) is in the tail of the epididymis, and takes origin from the 
duct of the epididymis or the seminal duct. It is a persistent canal of the Wolffian 
body. It extends up the cord for two or three inches and terminates by a blind 
extremity, which is occasionally bifurcated. It may be as much as fourteen 
inches in length. Its structure is similar to that of the seminal duct. 
The Seminal Duct or Vas Deferens (ductus deferens) (Figs. 1074, 1075, 1076, 1080, 
1081, and 1118).-The seminal duct or vas deferens, the excretory duct of the testis, 
is the continuation of the epididymis. Commencing at the lower part of the globus 
minor, it ascends along the posterior border of the testis and inner side of the epi- 
didymis, and along the back part of the spermatic cord, through the inguinal canal 
to the internal or deep abdominal ring. From the ring it curves around the outer 
side of the internal epigastric artery and vein, crosses the external iliac vessels, and 
descends into the pelvis at the side of the bladder; it arches backward and down- 
ward to its base, crossing over the obliterated hypogastric artery and to the inner 
side of the ureter. At the base of the bladder it lies between that viscus and the 
rectum, running along the inner border of the seminal vesicle. Behind the bladder 
it becomes enlarged and sacculated, forming the ampulla (ampulla ductus deferentis) 
(Fig. 1081), and then, becoming narrowed at the base of the prostate, unites with 
the duct of the seminal vesicle to form the ejaculatory duct (Fig. 1082). From the 
internal abdominal ring to the middle of the ampulla the seminal duct is beneath 
the peritoneum. The vas deferens offers a hard and cord-like sensation to the 
•fingers; it is about two feet in length, of cylindrical form, and about a line and 
a quarter in diameter. Its walls are dense, measuring one-third of a line, and its 
canal is extremely small, measuring about half a line. 
Structure.-The vas deferens consists of three coats: 1. An external or areolar 
coat (tunica adventitia). 2. A muscular coat (tunica muscularis), which in the 
greater part of the tube consists of two layers of unstriped muscular fibre: an inner 
layer of thin longitudinal fibres (stratum internum) existing only at the beginning, 1474 
THE MALE ORGANS OF GENERATION 
a thick layer of circular fibres (stratum medium), and a thick external layer of 
longitudinal fibres (stratum externum). 3. An internal or mucous coat (tunica 
mucosa), which is pale, and arranged in longitudinal folds; its epithelial cells are 
of the columnar variety. 
Organ of Giraldes (paradidymis).-This term is applied to a small body of 
rounded shape in the lower end of the spermatic cord, in front of the blood- 
vessels. It consists of a small collection of minute vesicles and a small collection 
of convoluted tubules. These tubes are lined with columnar ciliated epithelium, 
and probably represents the remains of a part of the Wolffian body. 
Surgical Anatomy.-Abnormalities in the descent and position of the testicle have been 
discussed (p. 1462). The testicle may require removal for malignant disease, tuberculous disease, 
cystic disease, in cases of large hernia testis, and in some instances of incompletely descended or 
misplaced testicles. The operation of double castration has also been, during the last few years, 
performed for enlargement of the prostate gland; for it has been found that removal of the tes- 
ticles is followed by very rapid and often considerable diminution in the size of the prostate. 
The operation is, However, one of severity, and is frequently followed by death in these cases, 
performed, as it necessarily is, in old men. Reginald Harrison has proposed to substitute for it 
excision of a portion of each vas deferens (vasectomy'). The operation of castration is a com- 
paratively simple one. An incision is made into the cavity of the tunica vaginalis from the 
external ring to the bottom of the scrotum. The coverings are shelled off the organ, and the 
mesorchium, stretching between the back of the testicle and the scrotum, divided. The cord is 
then isolated, and an aneurism needle, armed with a double ligature, passed under it, as high 
as is thought necessary, and the cord tied in two places, and divided between the ligatures. 
Sometimes, in cases of malignant disease, it is desirable to open the inguinal canal and tie the 
cord as near the internal abdominal ring as possible. 
A collection of serous fluid in the sac of the vaginal tunic of the testicle is known as an ordinary 
or testicular hydrocele. In congenital hydrocele a communication remains between the tunica 
vaginalis testis and the peritoneal cavity. This communication should have closed during 
development. In infantile hydrocele the tunica vaginalis and part of the funicular process are 
distended with fluid, but the funicular process is closed above and the cavity of the hvdrocele 
does not communicate with the peritoneal cavity. In encysted hydrocele of the cord the funicular 
process is closed above and below, but between these points is not obliterated. In funicular 
hydrocele the funicular process is closed below and open above. Congenital hvdrocele can 
usually be cured by the application of a truss. This obliterates the upper end of the funicular 
process, and the obliteration once begun may proceed to completion. If it does not, the condi- 
tion has become an infantile hydrocele. An infantile hydrocele can usually be cured by multiple 
punctures or tapping. The same is true of encysted hydrocele of the cord. In hvdrocele of the 
funicular process wear a truss for a time and then tap. In ordinarv testicular hvdrocele incise 
and pack, or incise and suture, the cut edge of the parietal layer of the tunic to the skin, or extir- 
pate the parietal layer of the tunic. A successful method is that of Longuet. He makes an 
incision, pulls out the testicle, and allows all the coats except the skin to fall behind and make 
a sheath for the cord. These coats are held behind by one catgut suture. A bed is made for 
the testicle beneath the skin toward the septum of the scrotum. The testicle is rotated on its 
long axis and placed in the bed, and the skin is sutured above it. This operation is known 
as extraserous transposition. If a portion of bowel enters an open vaginal process the condition 
is congenital hernia. 
In infantile hernia the funicular process is closed above but not below, and the hernia descends 
in a special sac back of the vaginal tunic. If the hernia pushes down on the vaginal process and 
causes it to double on itself the condition is encysted infantile hernia. 
The Semen and the Spermatozoids.-Semen consists of spermatozoids with liquids 
and solids. Part of the semen comes from the testicles, most of it from accessory 
glands-that is, from the glands of the seminal ducts, the seminal vesicles, the pros- 
tate gland, and Cowper's glands. Semen is a viscid, whitish fluid, of alkaline 
reaction and characteristic odor. It contains water and about 18 per cent, of 
solid matter. In this solid matter are fat, cholesterin, lecithin, proteids, nuclein, 
xanthin, chlorides, sulphates, and phosphates of sodium and potassium. Bott- 
cher's crystals, which can be obtained from semen, are composed of phosphate of 
spermine. Spermine is a nitrogenous substance. The fluid portion of semen 
carries and probably nourishes the living cells known as spermatozoids. THE SEMINAL VESICLES 
1475 
The spermatozoids (r ig. 1081) are minute, thread-like bodies, which constitute the 
essential elements of the semen. Each consists of a head, a middle piece or body, 
and an elongated filament or tail. The head, on surface view,appears oval in shape, 
but if seen in profile it is narrow and pointed at its free end. It represents the 
modified nucleus of the spermatid, and consists chiefly of chromatin, and so 
stains readily with nuclear reagents; it is covered by a thin cap of protoplasm. 
The body is a short cylindrical or conical piece, inter- 
vening between the head and tail, and is therefore 
sometimes spoken of as the intermediate segment. 
The tail is about four times the combined lengths of 
the head and body; its terminal part is extremely fine, 
and is named the end-piece. Contained within the 
body and tail is an axial filament, surrounded, except 
in the end-piece, by a thin layer of protoplasm; this 
axial filament terminates just below the head in a 
rounded knob or button. In virtue of their tails, 
which act as propellers, the spermatozoids, in the 
fresh condition, are capable of free movement, and 
if placed in favorable surroundings (e. g., in the 
female passages) may retain their vitality for some 
days or even weeks. 
Head 
Head. 
Middle 
" piece 
Middle 
piece 
Main piece 
of 
the 
tail 
THE SEMINAL VESICLES (VESICULAE 
SEMINALES) (Figs. 1082, 1083). 
-End piece 
The seminal vesicles are two lobulated membran- 
ous pouches placed between the base of the bladder 
and the rectum, serving as reservoirs for the semen, 
and secreting a fluid to be added to the secretion of 
the testicles. Each sac is somewhat pyramidal in 
form, the broad end being directed backward and the narrow end forward toward 
the prostate. It measures about two and a half inches in length, about five lines 
in breadth, and two or three lines in thickness. They vary, however, in size, not 
only in different individuals, but also in the same individual on the two sides. The 
upper surface is in contact with the base of the bladder, extending from near the 
termination of the ureters to the base of the prostate gland. The under surface 
rests upon the rectum, from which it is separated by the recto-vesical fascia. 
Their posterior extremities diverge from each other. Their anterior extremities 
are pointed, and converge toward the base of the prostate gland, where each joins 
with the corresponding seminal duct to form the ejaculatory duct. Along the 
inner margin of each vesicle runs the enlarged and convoluted vas deferens. The 
inner border of the vesicle and the corresponding seminal duct form the lateral 
boundaries of a triangular space, limited behind by the recto-vesical peritoneal 
fold; the portion of the bladder included in this space rests on the rectum. 
Each vesicle consists of a single tube, coiled upon itself and giving off several 
irregular caecal diverticula (Fig. 1082), the separate coils, as well as the diverticula, 
being connected together by fibrous tissue. When uncoiled this tube is about the 
diameter of a quill, and varies in length from four to six inches; it terminates pos- 
teriorly in a cul-de-sac; its anterior extremity becomes constricted into a narrow 
straight duct, the excretory duct (ductus excretorius} (Fig. 1083), which joins with 
the corresponding seminal duct, and forms the ejaculatory duct. 
The Ejaculatory Ducts (ductus ejaculatorii) (Fig. 1083).-The ejaculatory ducts 
a re two in number,one on each side. Each duct is formed by the junctionof the duct 
of the seminal vesicle with the seminal duct. Each duct is about three-quarters of 
Fig. 1081.-Spermatozoid of man. 
At the left a surface view is shown ; 
at the right a lateral view. X 1200. 
(Szymonowicz, after Retzius.) THE MALE ORGANS OF GENERATION 
1476 
an inch in length; it commences at the base of the prostate, and runs forward and 
downward between the middle and lateral lobes of that gland, and along the side of 
the sinus pocularis, to termi- 
nate by a separate slit-like 
orifice close to or just within 
the margins of the sinus. The 
ductsdiminish insizeand also 
converge toward their termi- 
nation. 
Structure.-The seminal 
vesicles are composed of three 
coats: an external or areolar 
(tunica adventitia); a middle 
or muscular coat (tunica mus- 
cularis), which is thinner than 
in the seminal duct, and is 
arranged in two layers, an 
outer,longitudinal,and inner, 
circular; an internal or mucous 
coat (tunica mucosa), which 
is pale, of a whitish-brown 
color, and presents a delicate 
reticular structure, like that 
seen in the gall-bladder, but 
the meshes are finer. The 
epithelium is columnar. 
The coats of the ejacula- 
tory ducts are extremely thin. 
They are: an outer fibrous 
MUSCULAR 
TUN IC 
VAS 
DEFERENS 
URETER' 
SEMINAL 
VESICLE' 
AMPULLA. 
COWPER'S 
GLAN DS 
EXCRETORY 
DUCT 
Fig. 1082.-The urinary bladder, distended, with surrounding struc- 
tures, viewed from behind. (Spalteholz.) 
layer, which is almost entirely 
lost after the entrance of the 
duct into the prostate; a 
layer of muscular fibres, con- 
sisting of an outer thin circu- 
lar and an inner longitudinal 
layer; and the mucous mem- 
brane. 
Vessels and Nerves.-The 
arteries supplying the vesic- 
ulae seminales are derived 
from the middle and inferior 
vesical and middle haemor- 
rhoidal. The veins and lym- 
phatics accompany the arte- 
ries. The lymphatics anas- 
tomose on the surface of the 
vesicle. The trunks from this 
network anastomose with the 
lymphatics of the bladder 
and prostate, and pass to the 
external and internal iliac glands. The nerves are derived from the pelvic plexus. 
AMPULLA 
^EXCRETORY 
1 DUCT 
SEMINAL 
'VESICLE 
SEMINAL^ 
VESICLES 
EXCRETORY 
DUCT 
EJACULATORY 
DUCT 
EJACULATORY 
DUCT 
SINUS 
POCULARIS 
VERUMONTANUM 
URETHRA 
Fig. 1083.-The ejaculatory ducts viewed from in front and above. 
(Spalteholz.) 
Surgical Anatomy.-The vesiculae seminales are often the seat of an extension of the dis- 
ease in cases of tuberculosis of the testicle, and should always be examined through the rectum 
before coming to a decision with regard to castration in this affection. The vesicles have been 
deliberately extirpated for local tuberculosis. In gonorrhoea the seminal vesicles may become 
acutely inflamed (acute seminal vesiculitis'). Chronic seminal vesiculitis may follow the acute 
form or may arise insidiously during gonorrhoea. THE FEMALE ORGANS OF GENERATION. 
EXTERNAL ORGANS (PARTES GENITALES EXTERNAE MULIEBRES). 
THE external organs of generation in the female are: the mons Veneris, the 
labia majora and minora, the clitoris, the meatus urinarius, and the orifice of 
the vagina. The term vulva (pudendum muliebre), as generally applied, includes 
all of these parts. 
FALLOPIAN TUBE 
PAROOPHORON 
UTERINE ORIFICE 
OF FALLOPIAN TUBE 
INFUNDIBULUM OF 
FALLOPIAN TUBE 
PAVILION OF. 
FALLOPIAN TUBE 
BLADDER 
ORGAN OF 
ROSENMULLER 
PERITONEUM 
OS UTERI- 
URETHRA 
-CLITORIS 
BARTHOLIN'S, 
gland' 
'LABIUM 
MINUS 
LABIUM 
MAJUS 
VESTIBULE OF VAGINA 
Fig. 1084.-Diagrammatic representation of the female reproductive organs and their relations to the bladder 
and urethra, lateral view. (Toldt.) 
THE MONS VENERIS (MONS PUBIS) (Figs. 1085, 1086) 
The mons Veneris is the rounded eminence in front of the pubic symphysis, 
formed by a collection of fatty tissue beneath the integument. It becomes covered 
with hair at the time of puberty. 
THE LARGE LIPS OR LABIA MAJORA (LABIA MAJORA PUDENDI) 
(Figs. 1085, 1086, 1087). 
Elie large lips or labia majora are two prominent longitudinal cutaneous folds 
extending downward from the mons Veneris to the anterior boundary of the 
perinaeum, and enclosing the common urino-sexual opening. Each labium ma jus 
(lalnum majus pudendi) has two surfaces, an outer, which is pigmented and 
1477 THE FEMALE ORGANS OF GENERATION 
1478 
covered with strong, crisp hairs; and an inner, which is smooth and is beset with 
large sebaceous follicles and is continuous with the genito-urinary mucous tract; 
between the two there is a considerable quantity of areolar tissue, fat, and a 
tissue resembling the dartos of the scrotum, besides vessels, nerves, and sweat and 
sebaceous glands. Between the labia majora is the pudendal slit (rima pudendi). 
The labia are thicker in front, where they form by their meeting the anterior 
commissure (commissura labiorum anterior). Posteriorly they are not really 
joined, but appear to become lost in the neighboring integument, terminating 
close to, and nearly parallel with, each other. Together with the connecting skin 
between them, they form the posterior commissure (commissura labiorum posterior), 
or posterior boundary of the vulval orifice. The interval between the posterior 
MONS VENERIS 
ANTERIOR 
"COM M ISSURE 
OF VULVA 
PREPUCE OF 
CLITORIS 
-LABIUM 
MAJUS 
•VULVAL 
CLEFT 
POSTERIOR 
COMMISSURE- 
OF VULVA 
PERINEUM 
ANUS 
POST-ANAL. 
FURROW 
Fig. 1085.-The female pudendum or vulva with the labia majora. (Toldt.) 
commissure and the anus, about an inch to an inch and a quarter in length, 
constitutes the obstetric perinaeum. The fourchette (frenulum labiorum pudendi) 
(Fig. 1086) is the anterior edge of the perinaeum, and between it and the hymen 
is a depression, the fossa navicularis of the vulva or the vestibule of the vagina {fossa 
navicularis vestibuli vaginae) (Fig. 1086). The labia majora correspond to the 
scrotum in the male. 
THE SMALL LIPS, NYMPHAE OR LABIA MINORA (LABIA MINORA PUDENDI) 
(Figs. 1085, 1086, 1087). 
The small lips are two small cutaneous folds, situated within the labia 
majora, and extending from the clitoris obliquely downward, outward, and back- THE CLITORIS 
1479 
ward for about an inch and a half on each side of the orifice of the vagina, 
between which and the labia majora they are lost in women who have borne 
children. In women who have not borne children they unite behind and usually 
form a fold (frenulum labiorum pudendi). Behind this fold is the fossa navicularis. 
Anteriorly, each lip divides into two limbs. The external limbs unite over the 
FOSSA 
NAVICULARIS 
Fig. 1086.-The vulva. External female organs of generation. 
glans clitoris to form the prepuce of the clitoris (praeputium clitoridis) (Fig. 1086). 
The internal limbs meet and unite beneath the glans clitoris and are attached 
to the under surface of the glans to form the fraenum (frenulum clitoridis). The 
nymphae are really modified skin. Their internal surfaces have numerous seba- 
ceous follicles (ylandulae vestibulares minor es). 
THE CLITORIS (Figs. 1086, 1087, 1089). 
The clitoris is an erectile structure analogous to the corpora cavernosa of the 
penis. It is situated beneath the anterior commissure, partially hidden between 
the anterior extremities of the labia minora. It is connected to the rami of the 
os pubis. It consists of two corpora cavernosa, each of which (corpus cavernosum THE FEMALE ORGANS OF GENERATION 
1480 
clitoridis) passes behind into the crus (crus clitoridis). Each crus is attached 
to the ramus of the pubis and ischium; the body (corpus clitoridis) is short 
and concealed beneath the labia; the free extremity (glans clitoridis) is a small 
rounded tubercle, consisting of spongy erectile tissue, and is highly sensitive. It 
is provided, like the penis, with a suspensory ligament (ligamentum suspensorium 
clitoridis), and with two small muscles, the Erectores clitoridis, which are inserted 
into the crura of the clitoris. The two corpora cavernosa are composed of erectile 
.POSTERIOR 
"fo R N IX 
ANTERIOR 
FORNIX 
CLITORIS- 
Fig. 1087.-Sagittal section of the lower part of a female trunk, right segment. SM. TNT., small 
intestine. (Testut.) 
tissue enclosed in a dense layer of fibrous membrane, united together along their 
inner surfaces by an incomplete fibrous pectin iform septum. 
To each crus of the clitoris goes a branch from the internal pudic artery, which 
branch is known as the deep artery of the clitoris. The dorsal arteries of the clitoris 
(arteriae dorsalis clitoridis) from the internal pudic send branches to the glans. 
The nerves of the clitoris consist of the dorsal nerves of the clitoris from the 
internal pudic nerve and sympathetic fibres from the hypogastric plexus. THE HYMEN 
1481 
THE VESTIBULE (VESTIBULUM VAGINAE). 
The vestibule of English and American writers is a triangular smooth surface 
between the clitoris and the entrance of the vagina (Fig. 1086). It is bounded 
on each side by the nymphae- The vestibule of the vagina is understood by the 
Germans to be the space at the sides of the vaginal orifice enclosed by the labii 
minora, as well as the space in front of the vagina.1 
Rectum 
Ovary. 
Suspensory 
. ligament 
of ovary 
Ovarian 
ligament' 
.Fallopian 
tube 
Broad 
ligament 
of uterus 
Urinary 
bladder 
'Uterus 
Round ligament 
of uterus 
Fig. 1088.-Female pelvic organs in situ, seen from above. (Bardeleben.) 
THE ORIFICE OF THE URETHRA OR THE MEATUS URINARIUS (ORIFICIUM 
URETHRAE EXTERNUM) (Figs. 1086, 1089). 
The external orifice of the urethra or the meatus urinarius is situated at the 
back part of the vestibule, about an inch below the clitoris and near the margin 
of the vagina, surrounded by a prominent elevation of the mucous membrane. 
Below the meatus urinarius is the orifice of the vagina (orificium vaginae) (Fig. 1086), 
more or less closed in the virgin by a membranous fold, the hymen (Fig. 1086). 
THE HYMEN (Figs. 1086, 1090). 
The hymen varies much in shape. Its commonest form is that of a ring, 
generally broadest posteriorly; sometimes it is represented by a semilunar fold, 
with its concave margin turned toward the pubes. A complete septum stretched 
across the lower part of the vaginal orifice is called an imperforate hymen. Occa- 
1 See note 89 by Dr. M. Eden Paul, in vol. iv. of Toldt's Atlas. 1482 
THE FEMALE ORGANS OF GENERATION 
sionally the hymen is cribriform, or its free margin forms a membranous fringe, 
or it may be entirely absent. It may persist after copulation, so that it cannot 
be considered as a test of virginity. After rupture of the hymen the small rounded 
elevations known as the carunculae myrtiformes are found as the remains of the 
structure. 
GLANDS OF BARTHOLIN (GLANDULA VESTIBULARIS MAJOR 
[BARTHOLINI]; (Fig. 1089). 
On each side of the posterior part of the commencement of the vagina is a 
round or oblong body, of a reddish-yellow color, and of the size of a horse-bean. 
SUSPENSORY LIGAMENT 
OF CLITORIS 
CLITORIS 
GLANS OF 
CLITORIS 
SPHINCTER 
VAGINAE 
MUSCLE 
ERECTOR 
CLITORIDIS 
MUSCLE 
ORIFICE OF. 
URETHRA 
LABIA, 
MINORA 
VAGINAL 
BULB 
VAGI NAL 
ORIFICE 
CARUNCULAE^ 
MYRTIFORMES 
SPHINCTER 
VAGINAE- 
MUSCLE 
EXCRETORY 
~ DUCT 
GLAND OF 
BARTHOLIN 
TRANSVERSE 
PERINEI- 
MUSCLE 
SPHINCTER 
ANI MUSCLE* 
POSTERIOR 
RUGOUS 
COLUMNS 
COMPRESSOR 
URETHRAE MUSCLE 
ANUS- 
TRANSVERSE 
PERINEI MUSCLE 
Fig. 1089.-The female external organs of generation dissected. (Spalteholz.) 
analogous to Cowper's gland in the male. It is called the gland of Bartholin, the 
gland of Duverney, the vulvo-vaginal gland or the suburethral gland (glandida vestibu- 
laris major [Bart hoi ini]). Bartholin's gland lies partly in the inferior or anterior 
leaf of the triangular ligament. The posterior portion of the bulbous vestibuli 
and the Bulbo-cavernous muscle partly cover it. Each gland opens by means of 
a long single duct immediately external to the hymen, in the angle or groove 
between it and the nympha (Fig. 101)0). THE VAGINA 
1483 
CRESCENTIC 
FRINGED 
BILABIAL 
Bl PERFORATE 
CRIBRIFORM 
Fig. 1090.-Varieties of hymen. (Testut, after Roze.) 
THE VAGINAL BULB OR BULB OF THE VESTIBULE (BULBUS VESTIBULI) 
(Fig. 1089). 
Extending from the clitoris, along either side of the vestibule (the term vestibule 
being used according to the German nomenclature) (p. 1481), and lying a 
little behind the nymphae, are two large oblong masses, about an inch in length, 
consisting of a plexus of veins enclosed in a thin layer of fibrous membrane. 
This plexus is superficial to the triangular ligament, and it is covered externally 
and inferiorly by the Bulbo-cavernous muscle. These bodies are narrow in front, 
rounded below, and are connected with the crura of the clitoris and rami of the 
pubes; they are termed by Kobelt the bulbi vestibuli, and he considers them 
analogous to the bulb of the corpus spongiosum in the male. Immediately in 
front of these bodies is a smaller venous plexus, continuous with the bulbi ves- 
tibuli behind and the glans clitoridis in front; it is called by Kobelt the pars inter- 
media, and is considered by him as analogous to that part of the body of the corpus 
spongiosum which immediately succeeds the bulb. The bulb receives its blood 
from the artery of the bulb (arteria bulbi vestibuli), which is a branch of the internal 
pudic. 
INTERNAL ORGANS (PARTES GENITALES INTERNAE MULIEBRIS). 
The internal organs of generation are-the vagina, the uterus and its appendages, 
the Fallopian tubes, the ovaries and their ligaments. 
THE VAGINA (Figs. 1084, 1087, 1093). 
The vagina extends from the vulva to the uterus. It is situated in the cavity 
of the pelvis, behind the bladder and in front of the rectum. Its direction is 
curved upward and backward, at first in the line of the pelvic outlet, and afterward 
in that of the axis of the cavity of the pelvis. Its walls are ordinarily in contact, 
and its usual shape on transverse section is that of an H, the transverse limb 
being slightly curved forward or backward, whilst the lateral limbs are somewhat 
convex toward the median line. Its length is about two and a half inches along 
its anterior wall (paries anterior), and three and a half inches along its posterior 
wall (paries posterior). It is constricted at its commencement, and becomes 
dilated medially, and narrowed near its uterine extremity; it surrounds the vaginal 1484 
THE FEMALE ORGANS OF GENERATION 
portion of the cervix uteri, a short distance from the os, its attachment extending 
higher up on the posterior than on the anterior wall of the uterus (Fig. 1096). 
The vaginal axis forms with the uterine axis an obtuse angle opening forward, 
and, as a rule, a little greater than a right angle (Fig. 1094). The fact that the 
attachment of the vagina to the cervix is above the external os causes the formation 
of a recess between the cervix and vaginal wall, known as the vaginal fornix (fornix 
vaginae). This recess is deeper posteriorly than it is laterally or in front. The 
anterior portion of the fornix is called the anterior fornix (Fig. 1087). The pos- 
terior portion is called the posterior fornix (Fig. 1087). The right and left portions 
are called the right and left lateral fornices. The vagina opens into the uro-genital 
cleft, between the labia minora and back of the urethra and clitoris. It opens by 
the vaginal orifice (orificium vaginae) (Fig. 1086). In the virgin the opening is 
partly closed by the hymen (p. 1481). After rupture of the hymen atrophied 
fragments of the torn membrane remain around the vaginal orifice, and are 
known as the carunculae myrtiformes (carunculae hymenales). 
Relations (Figs. 1084 and 1087).-The upper part of the anterior wall of the 
vagina is in relation with the base of the bladder, being separated from that viscus 
by lax connective tissue. Lower down the middle line of the anterior wall and 
closely joined to it is the urethra. The upper part of the posterior wall, near 
the middle line, is covered for a quarter of an inch or more with peritoneum, 
which forms the anterior wall of the depths of the recto-vaginal pouch of perito- 
neum or pouch of Douglas (excavatio rectouterina \Douglasi\) (Fig. 1096), between 
the uterus and vagina and the rectum. The portion of the posterior wall below 
the level of the pouch of Douglas is placed close to the rectum, a layer of pelvic 
fascia intervening. As the vaginal orifice is neared, the rectum and vagina 
separate, and interposed between them is a mass of fibro-fatty tissue called the 
perinaeum or perineal body. Its sides are enclosed between the Leva tores ani 
muscles. The ureter toward its termination (Fig. 1097) lies near the lateral wall 
of the vagina, passing at this point in a direction downward, inward, and slightly 
forward to reach the bladder. The vagina near its termination passes through 
the triangular ligament, and upon its sides are the bulbs of the vestibule, the 
glands of Bartholin, and the Bulbo-cavernous muscle. 
Structure.-The vagina consists of an internal mucous lining, of a muscular coat, 
and between the two of a layer of erectile tissue. 
The Mucous Membrane (tunica mucosa) (Fig. 1093).-The mucous membrane is 
continuous above with that lining the uterus. Its inner surface presents, along 
the anterior and posterior walls, a longitudinal ridge or raphe, called the rugous 
columns of the vagina (columna rugarum anterior et posterior). The anterior col- 
umn extends upward as far as the external orifice of the urethra, forming the 
carina urethralis vaginae. Numerous transverse ridges or rugae (rugae vaginales) 
extend outward from the raphe on either side. These rugae are divided by fur- 
rows of variable depth, giving to the mucous membrane the appearance of being 
studded over with conical projections or papillae; they are most numerous near 
the orifice of the vagina, especially in females before parturition. The epithelium 
covering the mucous membrane is of the squamous variety. The submucous tissue 
is very loose and contains numerous large veins, which by their anastomoses 
form a plexus, together with smooth muscular fibres from the muscular coat; it 
is regarded by Gussenbauer as an erectile tissue (see p. 1485). It contains a 
number of mucous crypts, but no true glands. 
The Muscular Coat (tunica muscularis).-The muscular coat consists of two 
layers: an external longitudinal, which is far the stronger, and an internal circular 
layer. The longitudinal fibres are continuous with the superficial muscular fibres 
of the uterus. The strongest fasciculi are those attached to the recto-vesical fascia 
on each side. The two layers are not distinctly separable from each other, but THE VAGINA 
1485 
are connected by oblique decussating fasciculi which pass from the one layer to 
the other. Above the triangular ligament the fibres are non-striated; in the region 
of the ligament they show striations. In addition to this the vagina at its lower 
end is surrounded by a band of striped muscular fibres, the sphincter vaginae 
(p. 461). External to the muscular coat is a layer of connective tissue containing 
a large plexus of blood-vessels. 
The Erectile Tissue.-The erectile tissue consists of a layer of loose connective 
tissue situated between the mucous membrane and the muscular coat; embedded 
in it is a plexus of large veins, and numerous bundles of unstriped muscular fibres 
derived from the circular muscular layer. The arrangement of the veins is 
similar to that found in other erectile tissues. 
EXTERNAL 
ILIAC GLANDS 
INTERNAL 
ILIAC GLANDS 
LATERAL 
'sacral glands 
AFFERENTS 
TO EXTERNAL 
ILIAC GLANDS 
AFFERENTS 
TO INTERNAL 
ILIAC GLANDS 
RETROVAGINAL 
NODULES 
Fig. 1091.-The lymphatics of the vagina. Schematic. (Poirier and Charpy.) 
Blood-vessels, Nerves, and Lymphatics.-The arteries of the vagina are branches 
of the vesico-vaginal artery; the vaginal branch of the uterine artery (p. 687), and 
branches of the internal pudic and middle haemorrhoidal. The veins form an abund- 
ant plexus around the wall of the vagina and pass to the internal iliac veins. The 
lymphatics (Fig. 1091) arise from the two communicating networks, one of which is 
below the mucous membrane, the other in the muscular wall. There is a third net- 
work around the vaginal wall, from which the collectors arise. The trunks from the 
upper third of the vagina pass to the external iliac glands; those from the middle 
third pass to the internal iliac glands; those from the lower third terminate in the 
glands at the promontory of the sacrum or in the lateral sacral glands.1 The nerves 
come from the third and fourth sacral nerves and from the utero-vaginal and 
vesical plexuses of the sympathetic. 
1 The Lymphatics. By Poirier, Cuneo, and Delamare. Translated and edited by Cecil H. Leaf. 1486 
THE FEMALE ORGANS OF GENERATION 
THE WOMB OR UTERUS (Figs. 1084, 1087, 1088, 1092, 1097). 
The uterus is the organ of gestation, receiving the fecundated ovum in its cavity, 
retaining and supporting it during the development of the foetus, and becoming 
the principal agent in its expulsion at the time of parturition. It is a hollow 
muscular organ. The non-pregnant uterus is contained in the cavity of the pelvis 
between the bladder and rectum (Figs. 1087 and 1088). It is rarely placed exactly 
in the mid-line, but inclines to one side or the other, more often to the left than 
to the right. The walls of the organ are extremely thick. The uterus is movable 
as a whole, and the body of the uterus is movable upon the neck. Its position 
varies with the condition of adjacent parts, especially the bladder and rectum. 
The cervix is more firmly fixed than the body anil fundus, and hence the latter 
vary more in position than the former. Normally, in an erect individual, with the 
bladder and rectum empty, the external os is at the level of the upper surface of 
the pubic symphysis (Fig. 1084) and in a frontal plane passing through the ischiatic 
spines. The long axis of the uterus is directed forward and upward (Fig. 1084), 
and is angled where the body and cervix join. Hence, normally, with the bladder 
MESOVARIUM 
ANTERIOR 
BORDER OF 
OVARY 
ISTH MUS c 
FALLOPIAN 
TUBE 
FUNDUS 
FALLOPIAN 
TUBE 
AMPULLA' 
LIGAMENT 
OF OVARY 
MESOSALPINX- 
LIGAMENT 
OF OVARY 
OVARIAN 
FIMBRIA 
ABDOMINAL 
ORIFICE 
'round 
LIGAMENT 
OF UTERUS 
FIMBRIAE OF 
FALLOPIAN TUBE 
OVARIAN ARTERY 
AND VEIN 
TUBAL 
EXTREMITY 
OF OVARY 
POSTERIOR 
LIP OF- 
CERVIX 
FORNIX OF 
VAGINA 
UTERINE 
EXTREM ITY 
OF OVARY 
OS UTERI 
EXTERNUM 
^VAGINAL 
PORTION OF 
CERVIX 
Fig. 1092.-The uterus, the left Fallopian tube and the left ovary in their connection with the broad ligament of 
the uterus, which has been fully unfolded. Seen from behind. From a virgin, aged nineteen years. (Toldt.) 
ANTERIOR LIP 
OF CERVIX 
empty, the uterus is anteverted and anteflexed. When the bladder fills the ante- 
version and anteflexion are almost abolished. If the bladder is overdistended and 
the rectum is empty, the uterus is pushed strongly backward, so that its long axis 
corresponds to the long axis of the vagina; in other words, it is retroverted. 
In the virgin state it is pear-shaped, flattened from before backward, and 
is retained in its position by the round and broad ligaments on each side, and 
projects into the upper end of the vagina below (Figs. 1092 and 1093). Its upper 
end, or base, is directed upward and forward; its lower end, or apex, downward 
and backward, in the line of the axis of the inlet of the pelvis. It therefore 
forms an angle with the vagina, since the direction of the vagina corresponds to 
the axis of the cavity and outlet of the pelvis. The non-pregnant adult uterus 
measures about three inches in length, two inches in breadth at its upper part, and 
nearly an inch in thickness, and it weighs from an ounce to an ounce and a half. 
It consists of two parts (Fig. 1092): (1) An upper and larger portion, consisting 
of the body and fundus. This portion is flattened from before backward. (2) A 
lower, smaller, and cylindrical portion, the cervix. THE WOMB OR UTERUS 
1487 
The Fundus (jundus uteri) (Fig. 1092).-The fundus is the upper broad 
extremity of the uterus. If a line is drawn from the uterine opening of one 
Fallopian tube to the other, the portion above the line is the fundus. The 
fundus is directly continuous with the body. 
The Body of the Uterus (corpus uteri) (Fig. 1092).-The body of the uterus is 
below and continuous with the fundus. In outline, when seen from in front or 
behind, it resembles a triangle, the base being above and the point being absent. 
MONS 
'VENERIS 
PREPUCE OF 
clitoris'" 
LABIUM 
^MAJUS 
GLANS 
CLITORIDIS 
EXTERNAL 
ORIFICE OF 
URETHRA 
FR/ENUM 
NYMPHA 
PARA-URETHRAL 
DUCT 
ORIFICE OF 
•DUCT OF 
BARTHOLIN'S 
GLAND 
HYMEN 
URETHRAL 
RIDGE 
BARTHOLIN'S 
GLAND 
POSTERIOR 
VAGINAL 
COLUMN 
MUCOUS 
MEMBRANE 
ANTERIOR 
VAGINAL 
COLUMN 
MUSCULAR 
COAT 
TRANSVERSE 
RUGAE 
-ANTERIOR 
WALL 
POSTERIOR, 
WALL 
ANTERIOR 
.LIP OF 
CERVIX 
VAGINAL 
FORN IX 
OS UTERI 
EXTERNUM 
VAGINAL 
PORTION OF 
CERVIX 
POSTERIOR 
'LIP OF 
CERVIX 
SUPRAVAGINAL 
PORTION OF' 
CERVIX 
Fig. 1093.-The female external genital organs of a virgin attached to the vagina, which has been isolated 
and opened, and a portion of the cervix uteri. (Toldt.) 
The anterior surface (fades vesicalis) passes on each side into the posterior surface 
(jades intestinalis) by the lateral border (margo lateralis'). 
The body gradually narrows from the fundus to the neck. Its anterior surface is 
so slightly rounded as to appear flattened. It is covered by peritoneum (Fig. 1092), 
which becomes separated from it at its union with the cervix, in order to form the 
utero-vesical pouch, which lies between the uterus and bladder (Fig. 1096). Its pos- 
terior surface is more rounded than the anterior, being convex transversely. It is THE FEMALE ORGANS OF GENERATION 
1488 
covered by peritoneum throughout (Fig. 1097), and separated from the rectum by 
some convolutions of the small intestine (Fig. 1087). The peritoneum which covers 
the posterior surface forms mostof the anterior wall of Douglas'scu/-</e-6,ac(Figs.853, 
1096 and 1097, and p. 1248). Its lateral margins (Figs. 1092 and 1097) are concave, 
and each gives attachment to the Fallopian tube above, the round ligament below, 
and in front of this the ligament of the ovary; behind both of these structures, and 
from the side of the womb the broad ligament passes. The division between the 
GARTNER'S 
DUCT 
TUBES 
Fig. 1094.-The parovarium. The mesosalpinx is partly removed. (Poirier and Charpy.) 
the body and the cervix is indicated externally by a slight constriction, and by the 
reflectionof the peritoneum from the anterior surface of the uterus on to the bladder, 
and internally by a narrowing of the canal called the internal os (Fig. 1095). 
The Neck or Cervix Uteri (Figs. 1092 and 1095).-The neck or cervix uteri is 
the lower constricted segment of the uterus; around its circumference is attached 
the upper end of the vagina (Figs. 1087, 1092, 1093, and 1096), which extends 
upward a greater distance behind than in front. The neck is spindle-shaped in 
those who have had no children, cylindrical in those who have had children. 
DUCT OF 
GARTNER 
AMPULLA 
MESOSALPINX 
ISTHMUS OF 
FALLOPIAN 
TUBE 
SEROUk 
COAT 
LONGITUDINAL 
FOLDS 
UTERINE 
ORIFICE OF 
FALLOPIAN TUBE 
UTERINE 
PORTION OF 
FALLOPIAN TUBE 
'EPOOPHORON 
ABDOMINAL 
ORI FICE 
UTERINE 
CAVITY 
MUSCULAR 
COAT 
MUCOUS 
MEMBRANE 
HYDATID OF 
MORGAGNI 
RIGHT 
LATERAL 
BORDER OF 
1 UTERUS 
UTEROVAGINAL 
VENOUS 
PLEXUS 
OS UTERI 
INTERNUM 
CAVITY OF, 
CERVIX 
HILUM OF 
OVARY 
OVARIAN 
VENOUS 
PLEXUS 
ARBOR 
VITAE 
MESOMETRIUM 
OS UTERI 
EXTERNUM 
\VAGINAL 
FORNIX 
Fig. 1095.- The uterus and the right Fallopian tube opened from behind. (Toldt.) 
The Supravaginal Portion (portio supravaginalis\cervicis\) (Figs. 1092 and 1096).- 
The supravaginal portion is not covered by peritoneum in front; a pad of cellular 
tissue is interposed between it and the bladder. Behind, the peritoneum is extended 
over it. 
The Vaginal Portion (portio vaginalis ceroids) (Figs. 1087, 1092, 1093, and 1096). 
-The vaginal portion is the lower end projecting into the vagina. It is round or THE WOMB OR UTERUS 
1489 
elliptical, the long axis of the elliptical figure being transversely placed. On its 
surface is a small aperture, the external mouth of the womb, or os uteri, or external os 
(orificinm uteri externum} (Figs. 1092, 1093, 1095, and 1096), generally circular in 
shape, but sometimes oval or almost linear. If a woman has borne children the 
opening is transverse and the margins are irregular. The margin of the opening is, 
in the absence of past parturition or 
disease, quite smooth. This aperture 
divides the vaginal portion of the cervix 
into two lips, an upper or posterior lip 
(labium posterius} and a lower or an- 
terior lip (labium anterius). On each 
side of the cervix and upper portion of 
the vagina there is a space containing 
bloodvessels and filled with loose cellu- 
lar tissue. This loose tissue passes 
upward between the layers of the broad 
ligament and is called parametrium. 
On each side of the cervix and three- 
quarters of an inch away is the termi- 
nal portion of the corresponding ureter. 
Folds and Ligaments.-The liga- 
ments of the uterus are eight in number. Some are simple folds of peritoneum; 
others contain connective tissue and muscle. The ligaments are as follows : one 
RECTAL PERITONEUM 
RECTOVAGINAL POUCH 
ANTERIOR AND POS- 
TERIOR LAYERS OF 
BROAD LIGAMENT 
^^VTERLOR ^ALl 
°X 
% 
VESICAL 
IPERITONEUM 
UTE RO-VESICAL 
POUCH 
p°Sr 
l°* 
SUPRA-VAGINAL 
PORTION OF 
CERVIX 
VAG'N* 
Fig. 1096.-The cervix uteri and upper end of the 
vagina, showing their relations to the peritoneum. 
Diagrammatic. (Testut.) 
ROUND 
LIGAMENT. 
External iliac 
artery. 
Ureter. 
Apex of Douglas's 
pouch. 
External iliac 
artery. 
Fig. 1097.-Douglas's p»uch. (From a preparation in the Museum of the Royal College of Surgeons of England.) 
anterior, one posterior, two lateral or broad, two sacro-uterine-all these being formed 
of peritoneum-and, lastly, two round ligaments. 1490 
THE FEMALE ORGANS OF GENERATION 
The Anterior Ligament or the Utero-vesical Fold or Vesico-uterine Ligament is 
reflected on to the bladder from the front of the uterus, at the junction of the 
cervix and body. It forms the utero-vesical pouch (excavatio vesicouterina) (Figs. 
1096 and 1097). 
The Posterior Ligament or the Recto-vaginal Fold passes from the posterior wall 
of the uterus over the upper fourth of the vagina, and thence on to the rectum and 
sacrum. It thus forms a pouch, called the recto-vaginal pouch or Douglas's pouch 
(Figs. 853, 1096, and 1097), the boundaries of which are, in front, the posterior 
wall of the uterus, the supravaginal portion of the cervix, and the upper fourth of 
the vagina; behind, the rectum and sacrum; above, the small intestine; and, 
laterally, the folds of Douglas or recto-uterine folds, which contain the sacro- 
uterine ligaments. 
The Lateral or Broad Ligament (lig amentum latum uteri') (Figs. 1088, 1098, 
and 1104) is a peritoneal fold which passes from each side of the uterus to the 
lateral wall of the pelvis as high as the external iliac vein. From this region 
comes the peritoneal fold called the suspensory ligament of the ovary (Fig. 1088). 
The two broad ligaments form a septum across the pelvis, which divides that 
cavity into two portions. In the anterior part are contained the bladder, urethra, 
and vagina; in the posterior part, the rectum. In the uterus normally placed the 
anterior surface of the broad ligament faces forward and downward, and the pos- 
terior surface faces upward and backward. The ligament is more nearly vertical 
FALLOPIAN" 
TUBE 
MESOSALPINX 
CORPUS 
ALBICANS 
SEROUS 
MEMBRANE 
CORPUS 
luteum 
GRAAFIAN 
FOLLICLE 
STROMA OF 
'OVARY 
LIGAMENT 
OF OVARY 
GRAAFIAN 
FOLLICLE 
MESOVARIUM 
MESOMETRIUM' 
Fig. 1098.- The broad ligament of the uterus, with 
the mesovarium, the mesosalpinx, the ovary, and 
the Fallopian tube in transverse section. (Toldt.) 
Fig. 1099.-Longitudinal section through the ovary. 
(Toldt.) 
at its pelvic insertion. The two layers of the broad ligament are mostly near 
to each other, to the side and below they separate and pass into the peritoneum 
of the lateral pelvic wall, the bladder and the rectum. Between the two layers 
of each broad ligament are contained-(1) the Fallopian tube superiorly; (2) the 
round ligament; (3) the ovary and its ligament; (4) the parovarium or organ of 
Rosenmuller, and the paro-ophoron; (5) loose connective tissue, which is called 
parametrium; (6) unstriped muscular fibre; and (7) blood-vessels and nerves. The 
Fallopian tube is in the free edge of the broad ligament, and is contained in a 
special fold, which is attached to the part of the ligament near the ovary, and is 
known by the name of the mesosalpinx (Figs. 1094, 1098, and 1104). If the 
mesosalpinx is spread out, it is seen to be roughly triangular; the base of the 
triangle is outward, the apex at the upper and outer angle of the uterus; the 
upper boundary is the Fallopian tube, and the lower boundary is the ovary and 
its ligament. Between the two layers of the mesosalpinx are the parovarium and 
the paro-ophoron. Between the fimbriated extremity of the tube and the lower 
attachment of the broad ligament is a concave rounded margin, called the infun- 
dibulo-pelvic ligament (Fig. 1103). THE WOMB OR UTERUS 
1491 
The ovary lies in a depression of the broad ligament called the ovarian bursa 
(bursa ovarii) (Figs. 1098 and 1104), and is joined to the ligament by a short fold, 
the mesovarium (Fig. 1104). 
The mesovarium passes upward from the posterior surface of the broad liga- 
ment (Fig. 1098). Beneath the mesovarium is a larger and thicker portion of 
the broad ligament, called the mesometrium (Fig. 1098). 
The Sacro-uterine or Utero-sacral Ligaments (plicae rectouterinae) are contained 
in the peritoneal folds of Douglas. They pass from the second and third bones 
of the sacrum, downward and forward on the lateral aspects of the rectum to be 
attached one on each side of the uterus at the junction of the supravaginal cervix 
and the body, this point corresponding internally to the position of the os 
internum. They contain fibrous tissue and unstriated muscle-fibre. Muscular 
fibres from the uterine wall to the rectal wall constitute the Recto-uterinus muscle 
(musculus rectouterinus). This muscle is part of the sacro-uterine ligaments. 
A Round Ligament (ligamentum teres) (Figs. 1088, 1097, 1100, and 1104) is 
attached on each side of the uterus. The two ligaments are rounded cords, 
between four and five inches in length, each situated between the layers of the 
broad ligament in front of and below the Fallopian tube. Commencing at the 
superior angle of the uterus, this ligament passes forward, upward, and outward 
through the internal abdominal ring, along the inguinal canal, to the labium 
majus, in which it becomes lost. The round ligament consists principally of 
muscular tissue prolonged from the uterus; also of some fibrous and areolar tissue, 
besides blood-vessels and nerves, enclosed in a duplicature of peritoneum, which 
in the foetus is prolonged in the form of a tubular process for a short distance into 
the inguinal canal. This process is called the canal of Nuck. It is generally oblit- 
erated in the adult, but sometimes remains pervious even in advanced life. It 
is analogous to the peritoneal pouch which precedes the descent of the testis. 
The Cavity of the Uterus (cavum uteri) (Fig. 1095).-The cavity of the uterus 
is small in comparison with the size of the organ, because of the great thickness of 
the wall. That portion of the cavity which corresponds to the body is triangular, 
flattened from before backward, so that its anterior and posterior walls are closely 
approximated, and having its base directed upward toward the fundus. At each 
superior angle is a funnel-shaped cavity, which constitutes the remains of one 
division of the body of the uterus into two cornua, and at the bottom of each cavity 
is the minute orifice of the Fallopian tube. At the inferior angle of the uterine 
cavity is. a small constricted opening, smaller and more nearly circular than the 
external os uteri, the internal orifice of the uterus or internal os uteri (orificium 
internum uteri) (Fig. 1095), which leads into the cavity of the cervix. 
The Cavity of the Cervix or Cervical Canal (canalis cervicis uteri) (Fig. 1095). 
-The cavity of the cervix or cervical canal extends from the internal os uteri to 
the external os uteri. It is somewhat fusiform, flattened from before' backward, 
broader at the middle than at either extremity, and communicates below with the 
vagina. The wall of the canal presents, anteriorly and posteriorly, a longitudinal 
column, from which proceed a number of small oblique columns, giving the appear- 
ance of branches from the stem of a tree; and hence the name uterine arbor vitae 
{plicae palmatae) applied to it. These folds usually become very indistinct after 
the first labor. 
Structure.-The uterus is composed of three coats: an external or serous coat, a 
middle or muscular coat, and an internal mucous or coat. 
The Serous Coat or Perimetrium (tunica serosa) (Figs. 1087, 1092, 1096, and 1097). 
-The serous coat is derived from the peritoneum; it invests the fundus and the 
whole of the posterior surface of the uterus; but covers the anterior surface only as 
far as the junction of the body and cervix. In the lower fourth of the posterior 
surface the peritoneum, though covering the uterus, is not closely connected with 1492 
THE FEMALE ORGANS OF GENERATION 
it, being separated from it by a layer of loose cellular tissue and some large veins. 
At the lateral margins of the uterus the serous coat passes on to the broad liga- 
ments. The serous coat adheres closely to the uterus, and it is very difficult to 
separate it from the muscle. 
The Muscular Coat (tunica muscularis) (Fig. 1095).-The muscular coat forms the 
chief bulk of the substance of the uterus. In the unimpregnated state it is dense, 
firm, of a grayish color, and cuts almost like cartilage. It is thick opposite the middle 
of the body and fundus, and thin at the orifices of the Fallopian tubes. It consists 
of bundles of unstriped muscular fibres, disposed in layers, intermixed with areolar 
tissue, blood-vessels, lymphatic vessels, and nerves. The muscular tissue is dis- 
posed in three layers-external, middle, and internal. 
The external layer is placed beneath the peritoneum, disposed as a thin plane 
on the anterior and posterior surfaces. It consists of fibres which pass trans- 
versely across the fundus, and, converging at each superior angle of the uterus, 
are continued on the Fallopian tube, the round ligament, the ligament of the 
ovary; some passing at each side into the broad ligament, and others running 
backward from the cervix into the sacro-uterine ligaments. The fibres of the 
external portion of the outer layer (stratum subserosum) are longitudinal. The 
fibres of the inner portion of the outer layer (stratum supravasculare) are partly 
circular and partly longitudinal. 
The middle layer of fibres (stratum vasculare), which is thickest, presents bundles 
of circular fibres closely connected with blood-vessels. In this layer are most of 
the blood-vessels. The circular fibres about the internal os form a distinct 
sphincter. Those which surround the orifices of the Fallopian tubes are arranged 
in the form of two hollow cones, the apices of which surround the orifices of the 
Fallopian tubes, their bases intermingling with one another on the middle of the 
body of the uterus. 
The internal or deep layer (stratum mucosum) consists of longitudinal fibres. 
Some consider the deeper portion of the muscular tissue of the uterus to be the 
muscularis mucosae. But the deep portion of the muscular substance is con- 
tinuous with the more superficial portion, and there is no submucous coat between 
the muscle and the mucous membrane. The deeper layer of muscular fibres of 
the uterus contains connective tissue and elastic fibres. The muscular tissue of 
the cervix contains more connective and elastic tissue than does the body of the 
uterus; hence, the cervix is harder and stiffer than the body. 
The Mucous Membrane (tunica mucosa) (Fig. 1095).-The mucous membrane 
is thin, smooth, and closely adherent to the subjacent muscular tissue. It is 
continuous, through the fimbriated extremity of the Fallopian tubes, with the 
peritoneum, and through the os uteri with the lining of the vagina. 
In the body of the uterus it is smooth, soft, of a pale-red color lined with columnar 
ciliated epithelium, and presents, when viewed with a lens, the orifices of numer- 
ous tubular follicles arranged perpendicularly to the surface. It is unprovided 
with any submucosa, but is intimately connected with the innermost layer of 
the muscular coat. In structure its corium differs from ordinary mucous membrane, 
consisting of an embryonic nucleated and highly cellular form of connective tissue, 
in which run numerous large lymphatics. In it are the tube-like uterine glands 
(glandulae uterinae), which are of small size in the unimpregnated uterus, but 
shortly after impregnation become enlarged and elongated, presenting a contorted 
or waved appearance towrard their closed extremities, which reach into the mus- 
cularis, and may be single or bifid. The uterine glands consist of a delicate 
membrane, lined with epithelium, which becomes ciliated towrard the orifices. 
In the cervix the mucous membrane is sharply differentiated from that of the 
uterine cavity. It is thrown into numerous oblique ridges, which diverge from an 
anterior and posterior longitudinal raphe, presenting an appearance which has THE WOMB OR UTERUS 
1493 
received the name of arbor vitae. In the upper two-thirds of the canal the mucous 
membrane is provided with numerous deep glandular follicles (glandulae cervicales 
uteri), which secrete a clear viscid alkaline mucus; and in addition, extending 
through the whole length of the canal, are a variable number of little cysts, pre- 
sumably follicles, which have become occluded and distended with retained secre- 
tion. They are called the ovules of Naboth. The mucous membrane covering the 
lower half of the cervical canal presents numerous papillae. The epithelium of 
the upper two-thirds is cylindrical and ciliated, but below this it loses its cilia, and 
gradually changes to squamous epithelium close to the external os. 
The Uterus at Different Ages.-The uterus of the foetus is in the abdominal cavity 
projecting above the brim of the pelvis. The cervix is considerably larger than 
the body. At birth the cervix is larger relatively than in the adult; there is no dis- 
tinct internal os distinguishing the cavity of the body of the uterus from the cavity of 
the cervix, and " the arbor vitae extends throughout the whole length of the uterus."1 
The growth of the uterus is slow until puberty is almost reached, when for a time 
the growth is rapid. The growth of the uterine body causes the mucous mem- 
brane of this part to lose its folds, hence the arbor vitae disappears from the body. 
In a woman who has had children the uterine cavity is larger than in a woman 
who has never borne a child. In advanced years the uterine wall becomes paler 
and hard and rigid from atrophic fibrous changes. A more distinct constriction 
separates the body and cervix. The internal os frequently and the external os 
occasionally are obliterated in old age. 
Abnormalities.-Very rarely the uterine cavity is divided into two by a septum. 
Occasionally the condition known as bicomate uterus exists. In this condition 
each lateral angle is prolonged into a horn or cornu. The uterus is formed by the 
union of the two ducts of Muller, and failure of fusion of these ducts makes a 
double uterus or a bicornate uterus. 
Changes at a Menstrual Period.-For several days before the menstrual flow 
begins the mucous membrane increases in thickness and vascularity and its sur- 
face is cast into folds. After these preparatory changes the superficial portions 
of the mucous membrane break down and are cast off, and bleeding begins. At 
the termination of menstruation the mucous membrane rapidly regenerates. At 
each menstrual period from 100 to 200 grammes of blood are discharged. The 
meaning of menstruation is uncertain. Pfliiger believes the wall of the uterus is 
made raw, so that if an impregnated ovum arrives it will adhere. Reichert believes 
that menstruation means that no impregnated ovum has arrived in the womb, and 
hence no bed is needed for one. 
Changes Induced by Pregnancy.-The muscular fibres hypertrophy enormously 
and become vastly longer and broader. There is a great increase in connective 
tissue, and new connective-tissue fibres pass between bundles of muscle. The 
peritoneal coat undergoes hyperplasia. It remains closely adherent to the uterus, 
except over the lower segment, from which region it can be easily stripped. The 
blood-vessels become large and tortuous. The nerves are increased in length and 
new filaments form. The lymphatics undergo, hypertrophy and hyperplasia 
(Prof. Barton Cooke Hirst). The uterus becomes spherical, and after the fourth 
month ovoidal. Early in pregnancy the increase in weight causes the uterus 
to descend in the pelvis. After the third month it rises progressively, and during 
the ninth month the fundus reaches the epigastrium. " Before term (four weeks 
in primiparae, ten days or one week in multiparae) the fundus sinks again, as 
the presenting part and lower uterine segment become engaged in the pelvic 
cavity. This phenomenon is explained by contraction of the overstretched 
abdominal walls."2 The womb is acutely anteflexed during the first three months 
1 Prof. Francis A. Dixon in Prof. Cunningham's Text-book of Anatomy. 
2 A Text-book of Obstetrics. By Prof. Barton Cooke Hirst. 1494 
THE FEMALE ORGANS OF GENERATION 
of pregnancy. After this period, as the womb rises, the anteflexion is diminished, 
but some degree remains, because the abdominal walls are too lax to hold the 
organ straight. The uterus passes somewhat to the right side and undergoes a 
rotation on its longitudinal axis, so that the anterior surface looks front and to the 
Branches to tube. 
Branches to fundus. 
Ovarian artery. 
Branch to round ligament. 
ROUND LIGAMENT. 
Uterine artery. 
Arteries of cervix. 
Uterine artery. 
Fig. 1100.-The arteries of the internal organs of generation of the female, seen from behind. (After Hyrtl.) 
Vaginal arteries. 
right. These changes in position are caused by fecal distention of the sigmoid. 
The intestines are above and back of the uterus. During the first four months the 
cervix softens and enlarges somewhat. The length of the cervical canal is not 
VESSELS FROM 
BODY OF FUNDUS 
OVARIAN 
LIGAMENT 
VESSELS* 
FROM TUBE 
.VESSELS OF 
ROUND LIGAMENT 
ANASTOMOSIS 
OF VESSELS 
VESSELS FROM 
CERVIX AND VAGINA 
CERVICAL 
VESSELS 
VAGINAL, 
LYMPHATICS 
Fig. 1101.-The lymphatic vessels of the uterus. (Poirier and Charpy.) 
altered during pregnancy, and the canal does not dilate until labor begins. During 
pregnancy the cervical glands secrete thick mucus, which coagulates and occludes 
the cervical canal; the round ligaments become stronger, and the layers of the 
broad ligament are separated toward their inner portions by the enlarging womb. THE WOMB OR UTERUS 
1495 
After parturition the uterus nearly regains its former size, usually weighing 
something over one and a half ounces; but its cavity is larger than in the virgin 
state, the external orifice is more marked, its edges present a fissured surface, its 
vessels are very tortuous, and its muscular layers are more defined. 
Vessels and Nerves (Fig. 1100).-The arteries of the uterus are the uterine, from 
the internal iliac, and the ovarian, from the aorta. They are remarkable for their 
tortuous course in the substance of the organ and for their frequent anastomoses. 
The uterine artery reaches the lower part of the uterus at the side and is pro- 
.JUXTA-AORTIC 
'glands 
JUXTA-AORTIC. 
GLAN DS 
VESSELS FROM 
BODY OF UTERUS 
VESSELS FROM 
NECK OF UTERUS 
TO LATERAL- 
SACRAL GLAND 
VESSELS FROM, 
NECK OF UTERUS' 
VESSEL OF 
FALLOPIAN TUBE 
VESSELS OF 
ROUND LIGAMENT 
•UTERUS 
Fig. 1102.-The lymphatics of the internal organs of generation in the female. (Poirier and Charpy.) 
longed as a large artery to the body and fundus, which ascends between the 
layers of the broad ligament. The uterine artery gives oft' a smaller branch, the 
cervical, which descends to supply the cervix and sends cervico-vaginal branches 
to the vagina. The azygos arteries of the vagina come from the cervico-vaginal 
reinforced by branches of the vaginal arteries (Fig. 1104). A median longitudinal 
vessel is formed in front and behind, which descends in the vaginal wall. The 
termination of the ovarian artery meets the termination of the uterine artery, 
and forms an anastomotic trunk from which branches are given off to supply 
the uterus. Dr. Byron Robinson, instead of describing the uterine and ovarian 1496 
THE FEMALE ORGANS OF GENERATION 
arteries as two vessels, describes them as parts of one vessel, the arteria uterina 
ovarica (p. 558). The veins are of large size, and correspond with the arteries. 
In the impregnated uterus these vessels form the uterine sinuses, consisting of 
the lining membrane of the veins adhering to the walls of the canals channelled 
through the substance of the uterus. They terminate in the uterine plexuses, 
which empty into the internal iliac veins. The lymphatics (Figs. 1101 and 1102) 
originate from three networks, a muscular network, a peritoneal network, and a 
network in the stroma. The trunks from these networks anastomose, and thus 
form another network beneath the peritoneum, and from the fourth network the 
collectors arise. The network of the cervix is continuous with that of the body. 
The collecting trunks from the cervical region number from five to eight. Some 
terminate in the external iliac glands, some in the internal iliac glands, some in the 
lateral sacral glands, or the glands of the promontory. The collecting trunks from 
the body terminate chiefly in the juxta-aortic or pre-aortic glands, but some termi- 
nate in the external iliac glands, and some in the inguinal glands.1 The nerves come 
chiefly from the utero-vaginal plexus, which continues into the hypogastric plexus 
and receives filaments from the third and fourth sacral nerves. The uterus also 
receives direct fibres from the hypogastric plexus and from the vesical plexus. 
Surgical Anatomy.-Pelvic cellulitis (parametritis) is inflammation of the pelvic cellular 
tissue. It is due to sepsis, and its usual antecedent is uterine sepsis. A laceration of the cervix 
may admit bacteria. An abscess may form. If it points in the vagina it should be incised through 
the vaginal wall. The uterus may require removal (hysterectomy) in cases of malignant disease 
or for fibroid tumors. Carcinoma is the most common form of malignant disease of the uterus, 
though cases of sarcoma do occur. Carcinoma may show itself either as a columnar carcinoma 
or as a squamous carcinoma; the former commencing either in the cervix or body of the uterus, the 
latter always commencing in the epithelial cells of the mucous membrane covering of the vaginal 
surface of the cervix. The columnar form may be treated in the early stage, before fixation has 
taken place, by removal of the uterus, either through the vagina or by means of abdominal 
section. The former operation is attended by the smaller death-rate. Vaginal hysterectomy 
may be performed in any case in which the uterus or the uterus and tumor are not too large to be 
withdrawn through the vagina. It is difficult in this operation to deal with adhesions and other 
complications in the upper part of the pelvis, and for this reason many surgeons prefer the abdom- 
inal operation. Vaginal hysterectomy is performed by placing the patient in the lithotomy position 
and introducing a large duckbill speculum into the vagina. The cervix is then seized with a vol- 
sellum and pulled down as far as possible and the mucous membrane of the vagina incised around 
the cervix as near to it as the disease will allow, especially in front, where the ureters are in 
danger of being wounded. A pair of dressing forceps are then pushed through into Douglas's 
pouch and opened sufficiently to allow of the introduction of the two forefingers, by means of 
which the opening is dilated laterally as far as the sacro-uterine ligaments. A somewhat similar 
proceeding is adopted in front, but here the bladder has to be separated from the anterior wall 
of the uterus for about an inch before the vesico-uterine fold of peritoneum can be reached. 
This is done by carefully burrowing upward with a director and stripping the tissues off the 
anterior uterine wall. When the vesico-uterine pouch has been opened and the opening dilated 
laterally, the uterus remains attached only by the broad ligaments, in which are contained the 
vessels that supply the uterus. Before division of the ligaments, these vessels have to be dealt 
with. The forefinger of the left hand is introduced into Douglas's pouch and an aneurism 
needle, armed with a long silk ligature, is inserted into the vesico-uterine pouch, and is pushed 
through the broad ligament of one side about an inch above its lower level and at some distance 
from the uterus. One end of the ligature is now pulled through the anterior opening, and in this 
way we have the lowest inch of the broad ligament, in which is contained the uterine artery, 
enclosed in a ligature. This is tied tightly, and the operation is repeated on the other side. The 
broad ligament is then divided on either side, between the ligature and the uterus, to the extent 
to which it has been constricted. By traction on the volsellum which grasps the cervix, the uterus 
can be pulled considerably farther down in the vagina, and a second inch of the broad ligament 
is treated in a similar way. This second ligature will embrace the pampiniform plexus of veins 
and, when the broad ligament has been divided on either side, it will be found that a third liga- 
ture can be made to pass over the Fallopian tube and top of the broad ligament, after the uterus 
has been dragged down as far as possible. After the third ligature has been tied and the struc- 
tures between it and the uterus divided, this organ will be freed from all its connections and can 
be removed from the vagina. This canal is then sponged out and lightly dressed with gauze, 
1 The Lymphatics. By Poirier, Cun£o, and Delamare. Translated and edited by Cecil H. Leaf. THE FALLOPIAN TUBE 
1497 
no sutures being used. The gauze may be removed at the end of the second day. In squamous 
epithelioma, amputation of the cervix is done by some in those cases where the disease is recog- 
nized before it has invaded the walls of the vagina or the neighboring broad ligaments. The 
operation consists in removing a wedge-shaped piece of the uterus, including the cervix, through 
the vagina and attaching the cut surfaces of the stump to the anterior and posterior vaginal walls, 
so as to prevent retraction. In view, however, of the continuity of the lymphatic network of the 
cervix with the lymphatics of the body, the operation is insufficient and should be condemned. 
Complete abdominal hysterectomy is rarely necessary, except for malignant disease. In this opera- 
tion the entire uterus is removed. The preliminary introduction of bougies into the ureters as 
practised by Kelly and Clark enables the surgeon to readily recognize the situations of these tubes. 
After the abdomen has been opened the uterine vessels are secured and the broad ligaments 
divided in a similar manner to that employed in vaginal hysterectomy, except that the proceeding 
is commenced from above. When the first two ligatures have been tied and the broad ligament 
divided, it will be found that the uterus can be raised out of the pelvis. A transverse incision 
is now made through the peritoneum, where it is reflected from the anterior surface of the uterus 
on to the back of the bladder and the serous membrane peeled from the surface of the uterus 
until the vagina is reached. The anterior wall of this canal is cut across. The uterus is now 
turned forward and the peritoneum at the bottom of Douglas's pouch incised transversely, and 
the posterior wall of the vagina cut across until it meets the incision on the anterior wall. The 
uterus is now almost free, and is held only by the lower part of the broad ligament on either 
side, containing the uterine artery. A third ligature is made to encircle this, and, after having 
been tied, the structures are divided between the ligature and the uterus. The organ can now 
be removed. The vagina is plugged with gauze, and the external wound closed in the usual 
way. The vagina acts as a drain, and therefore the opening into it is usually left unsutured. In 
some cases of uterine fibroid the abdomen is opened and the tumor is removed, but the uterus is 
not taken away. This operation is called myomectomy. This operation is suited only to solitary 
subperitoneal or interstitial tumors (Penrose). 
The common operation for uterine fibroids is supravaginal amputation. The uterus is 
cut away and the cervical flaps are sutured. Before the technique of hysterectomy was per- 
fected and before myomectomy was devised the favorite operation for uterine fibroids was 
salpingo-odphorectomy, and by it a large majority of cases operated upon were cured. When it 
succeeds a premature menopause is induced and the tumor shrinks. The operation is useless if 
a woman is past the menopause, and is apt to fail if the tumor is very soft or very large. 
THE ADNEXA OR APPENDAGES OF THE UTERUS. 
The appendages of the uterus are the Fallopian tubes, the ovaries and ovarian 
ligaments, and the round ligaments. They are placed in the following order: in 
front is the round ligament; the Fallopian tube occupies the upper margin of the 
broad ligament; the ovary and its ligament are behind and below both. 
THE FALLOPIAN TUBE (TUBA UTERINA [FALLOPII]) 
(Figs. 1092, 1097, 1098, 1103, 1104). 
The Fallopian tubes or oviducts convey the ova from the ovaries to the cavity 
of the uterus. They are two in number, one on each side, situated in the upper 
margin of the broad ligament, extending from each superior angle of the uterus to 
the sides of the pelvis. Each tube is about four inches and a quarter in length, 
and is placed in a fold of peritoneum, which is part of the broad ligament and is 
called the mesosalpinx (Fig. 1098). Each tube is described as consisting of four 
portions: (1) the isthmus (isthmus tubae uterinae) (Fig. 1103), or inner constricted 
third; (2) the ampulla (ampulla tubae uterinae) (Fig. 1103), or outer dilated portion, 
which curves over the ovary; and (3) the infundibulum, the funnel-like expansion of 
the tube, at the bottom of which is the abdominal orifice or pavilion (ostium abdom- 
inale tubae uterinae) (Fig. 1103). The abdominal orifice has a small diameter (2 
mm. when relaxed to its full extent). The margin of the infundibulum is rendered 
irregular by the presence of numerous small processes, the fimbriae (fimbriae tubae). 
This end of the tube is called the fimbriated extremity (Fig. 1103), because of these 
processes. The surfaces of the fimbriae looking into the cavity of the infundi- 
bulum are covered with mucous membrane continuous with the tubal mucous 1498 
THE FEMALE ORGANS OF GENERATION 
membrane. The outer surfaces are covered with peritoneum. One of the fimbriae 
is attached to the ovary and is called the ovarian fimbria (fimbria ovarica) (Fig. 
1103). (4) The uterine portion of the tube {pars uterina) (Fig. 1095) is in the uterine 
wall. The opening into the uterus (ostium uterinum tubae) is even smaller than 
the abdominal opening, and will admit only a small bristle. The general direc- 
tion of the Fallopian tube is outward, backward, and downward. In connec- 
tion with the fimbriae of the Fallopian tube or with the broad ligament close to 
them there is frequently one or more small vesicles floating on a long stalk of 
peritoneum. These are termed the hydatids of Morgagni (appendices vesiculosi). 
They are representative of small portions of the upper extremity of the Wolffian 
duct. 
Course Pursued by the Fallopian Tube (Figs. 1088 and 1103).-The tube on each 
side begins at the upper and outer angle of the uterus and passes outward in a 
horizontal direction toward the uterine extremity of the ovary. It then bends 
almost to a right angle and ascends close to the pelvic wall and in front of the 
anterior margin to the tubal extremity of the ovary. At this point it turns sharply 
Parovarium. 
Fimbriated 
extremity. 
Ostium 
abdominale. 
Fimbria ovarica. 
Fig. 1103.-Uterine appendages, seen from behind. (Henle.) 
downward and a little backward, and the inner surface of the infundibulum comes 
to lie upon the free margin and the posterior portion of the inner surface of the 
ovary. "The fimbria ovarica thus ascends in a recurrent direction to the extrem- 
itas tubaria."1 
Structure.-The Fallopian tube consists of three coats-serous, muscular, and 
mucous. 
The external or serous coat (tunica serosa) (Fig. 1098) is peritoneal. Beneath 
this lies the tunica adventitia, composed of lax connective tissue. 
The middle or muscular coat (tunica muscularis) consists of an external longi- 
tudinal layer (stratum longitudinals), and an internal circular layer (stratum cir- 
culars) of muscular fibres continuous with those of the uterus. 
The internal or mucous coat (tunica mucosa) is continuous with the mucous lining 
of the uterus and, at the free extremity of the tube, with the peritoneum. It is 
thrown into longitudinal folds (plicae tubariae), which in the outer, larger part of 
the tube or ampulla (plicae ampullares) are much more extensive than in the 
narrow canal of the isthmus (plicae isthmicad). The lining epithelium is columnar 
and ciliated. This form of ephithelium is also found on the inner surface of the 
1 Spalteholz's Atlas. English edition by Barker. THE OVARY 
1499 
fimbriae, while on the outer or serous surfaces of these processes the epithelium 
gradually merges into the endothelium of the peritoneum. 
Vessels and Nerves.-The chief artery of the tube is the tubal branch of the 
uterine artery (ramus tubarius) (Fig. 1100). It also receives branches from the 
ovarian (Fig. 1100). Some of the tubal veins empty into the uterine veins, some 
into the ovarian veins. The lymphatics (Figs. 1101 and 1102) coming from the 
tube unite with the trunks coming from the uterus and ovary and terminate in 
the juxta-aortic glands. The nerves come from the same plexuses that send 
branches to the uterus and ovary. 
The Epo-ophoron, Parovarium or Organ of Rosenmuller (Figs. 1094,1095, and 
1103) is placed in the mesosalpinx, between the ovary and tube. It consists of a 
number of epithelial-lined closed tubes. This structure can be readily seen if the 
mesosalpinx is stretched and held in front of the light. One of these tubes runs 
parallel to the Fallopian tube and is called Gartner's duct (ductus epoophori longitu- 
dinalis). A number of tubes (ductuli transversi} ascend from near the ovary and 
Fimbriated extremity 
of tube. 
Fallopian tube. 
Fimbria 
orarica. 
Broad ligament, 
upper part. 
Ovarian 
vessels. 
Artery 
vein. 
Uterine artery. 
Vaginal 
artery. 
Os externum. 
Fig. 1104.-The uterus and its appendages. Posterior view. The parts have been somewhat displaced from 
their proper position in the preparation of the specimen; thus the right ovary has been raised above the Fallo- 
pian tube, and the fimbriated extremities of the tubes have been turned upward and outward. (From a prepa- 
ration in the Museum of the Royal College of Surgeons of England.) 
Vagina, anterior wall. 
each empties into Gartner's duct at a right angle. Gartner's duct is a portion of 
the Wolffian duct, which has persisted and is represented in the male by the canal 
of the epididymis. The tubules which join the duct "are derived from the meso- 
nephros and represent the vasa efferentia and coni vasculosi of the testis, and 
probably also the ductuli aberrantes of the canal of the epididymis."1 
The Paro-ophoron is within the mesosalpinx, but is nearer to the uterus than 
is the epo-ophoron. It consists of several small tubules, which can be seen in an 
adult only by the aid of a pocket lens. They are visible to the naked eye in a child 
at birth. It represents the organ of Giraldes in the male and is derived from the 
mesonephros. 
THE OVARY (Figs. 1088, 1092, 1094, 1095, 1097, 1098, 1099, 1103, 1104). 
The ovaries (ovaria), the testes muliebres of Galen, are two in number and are 
analogous to the testes in the male. They are oval-shaped bodies of an elongated 
1 Prof. Cunningham's Text-book of Human Anatomy. 1500 
THE FEMALE ORGANS OF GENERATION 
form, flattened from above downward, situated one on each side of the uterus, 
in the posterior layer of the broad ligament behind and below the Fallopian tube. 
Each ovary is connected by its anterior straight margin to the broad ligament; 
by its lower extremity to the uterus by a proper ligament, the ligament of the 
ovary (ligamentum ovarii proprium) (Fig. 1103); and by its upper end to the 
fimbriated extremity of the Fallopian tube by the ovarian fimbria (fimbria ovarica) 
(Fig. 1103), its mesial and lateral surfaces and posterior convex border are free 
(Fig. 1104). The ovaries are of a grayish-pink color, and present either a smooth 
or a puckered, uneven surface. They are each about an inch and a half in 
length, three-quarters of an inch in width, and about a third of an inch thick, 
and weigh from one to two drachms. 
The exact position of the ovary has been the subject of considerable difference 
of opinion, and writers are in conflict as to what is to be regarded as the normal 
position. The fact appears to be that the ovary is differently placed in different 
individuals. The two ovaries are seldom placed in absolutely identical positions. 
Hasse has described the ovary as being situated with its long axis transverse, or 
almost transverse, to the pelvic cavity. Schultze, on the other hand, believes that 
its long axis is antero-posterior. Kblliker asserts that the truth lies between 
these views, and that the ovary is placed obliquely in the pelvis, its long axis 
lying parallel to the external iliac vessels, with its surface directed inward and out- 
ward, and its convex free border upward. His has made some important observa- 
tions on this subject, and his views are largely accepted. He teaches that the 
uterus rarely lies symmetrically in the middle of the pelvic cavity, but is generally 
inclined to one or other side, most frequently to the left, in the proportion of three 
to two. The position of the two ovaries varies according to the inclination of the 
uterus. When the uterus is inclined to the left, the ovary of this side lies with 
its long axis vertical and with one side closely applied to the outer wall of the 
pelvis, while the ovary of the opposite side, being dragged upon by the inclina- 
tion of the uterus, lies obliquely, its outer extremity being retained in close appo- 
sition to the side of the pelvis by the infundibulo-pelvic ligament. When, on 
the other hand, the uterus is inclined to the right, the position of the two 
ovaries is exactly reversed, the right being vertical and the left oblique. In 
whichever position the ovary is placed, the Fallopian tube forms a loop around it, 
the uterine half ascending obliquely over it, and the outer half, including the 
dilated extremity, descending and bulging freely behind it. From this extremity 
the fimbriae pass upward on to the ovary and closely embrace it. 
Waldeyer1 states, as the result of the examination of fifty female subjects, 
ranging from early childhood to advanced age, that the ovary "lies on the lateral 
pelvic wall and vertically when the woman takes the erect posture." Its tubal 
extremity is near the external iliac vein; its uterine end is directed downward, 
while the Fallopian tube overlies it so as to cover it on its medial face entirely or 
nearly so. Its convex margin looks downward and backward toward the pelvic 
cavity and rectum, while its straight margin or hilum lies laterally on the pelvic 
wall attached to the mesosalpinx. He also finds that it lies in a distinct but 
shallow groove (fossa ovarii) limited above by the hypogastric artery and below 
by the ureter, in such a manner that the ureter lies along the convex margin 
of the ovary, and the hypogastric artery passes near the hilum or straight margin. 
The ovary possesses two poles or extremities: (1) An outer, superior or tubal 
extremity (extremitas tubaria ovarii). (2) An inner, inferior or uterine extremity 
(extremitas uterina ovarii). The ovary has two surfaces, an inner surface (facies 
mcdialis), which is also upper; an outer surface (facies lateralis), which is also 
lower. The posterior or free border (margo liber) is markedly convex. The anterior 
1 Journal of Anatomy and Physiology, vol. xxxii. THE DESCENT OF THE OVARY 
1501 
border (mar go mesovaricus) is almost straight and is narrow. The anterior border 
is not free, but is joined to the posterior layer of the broad ligament by a peritoneal 
fold known as the mesovarium. There is a groove in the anterior border called the 
hilum (hilus ovarii), through which vessels and nerves to pass, and emerge from 
the ovary. 
Supports and Connections of the Ovary. 
From its upper extremity a peritoneal fold is continuous with the peritoneum 
over the iliac vessels and Psoas muscle. It is called the ovario-pelvic fold or the 
suspensory ligament (ligamentum suspensorium ovarii) (Fig. 1088). It is in reality 
a portion of the broad ligament, and within it are the ovarian vessels and nerves. 
The vessels (Fig. 1104) and nerves go to the anterior border of the ovary and are 
surrounded by a peritoneal sheath derived from the posterior layer of the broad 
ligament; it is thus evident that the anterior border of the ovary is connected to 
the posterior portion of the broad ligament by a very short mesentery, the meso- 
varium1 (Fig. 1098). The ligament of the ovary or ovarian ligament (Figs. 1088 
and 1103) is a round, cord-like structure, composed chiefly of non-striated muscle- 
fibres, which passes between the two folds of the broad ligament from the lower 
extremity of the ovary to the lateral angle of the uterus. The ovarian fimbria 
(Fig. 1103), as previously stated, passes to the upper extremity of the ovary 
from the extremity of the Fallopian tube. 
The Descent of the Ovary. 
In the female there is a gubernaculum which effects a considerable change in 
the position of the ovary, though not so extensive a change as is effected upon the 
male testicle. The gubernaculum in the female, as it lies on either side in con- 
tact with the fundus of the uterus formed by the union of the Mullerian ducts, 
contracts adhesions to this organ and thus the ovary is prevented from descending 
below this level. The remains of the gubernaculum-that is to say, the part 
between the attachment of the cord to the uterus to its termination in the labium 
majus-ultimately forms the round ligament of the uterus. A pouch of peri- 
toneum accompanies it along the inguinal canal, analogous to the funicular process 
in the male; it is called the canal of Nuck. In rare cases the gubernaculum fails 
to contract adhesions to the uterus, and then the ovary descends through the 
inguinal canal into the labium majus, extending down the canal of Nuck. 
Under these conditions, the position of the ovary resembles the position of the 
testicle in the male. 
The Ovary at Different Ages.-The ovary of childhood is smooth and 
even. The rupture of Graafian follicles, repeated many times, causes the surface 
of the ovary to become pitted, puckered, fibrous, and uneven in old age. The sur- 
face of the ovary is grayish-red in color. The corpus luteum of a non-pregnant 
woman slowly degenerates and disappears. The corpus luteum of an impreg- 
nated woman enlarges during pregnancy. 
Structure (Figs. 1098, 1099, 1105, and 1106).-The ovary consists of a number 
of Graafian follicles or vesicles embedded in the meshes of a stroma or framework, 
and invested by a serous covering derived from the peritoneum. 
Serous Covering.-Though the investing membrane of the ovary is continuous 
with the peritoneum near the hilum of the ovary (the point of junction being 
indicated by a narrow white line), it differs essentially from the peritoneum, 
inasmuch as it is an epithelial structure and consists of a single layer of columnar 
epithelial cells, instead of the flattened endothelial cells of other parts of the 
1 Prof. Cunningham's Text-book of Anatomy. THE FEMALE ORGANS OF GENERATION 
1502 
membrane; this has been termed the germinal epithelium of Waldeyer, and gives 
to the surface of the ovary a dull-gray aspect instead of the shining smoothness 
of serous membranes generally. 
Stroma.-The stroma is a peculiar soft tissue, abundantly supplied with blood- 
vessels, consisting for the most part of spindle-shaped cells, with a small amount 
of ordinary connective tissue. These cells have been regarded by some anatomists 
as unstriped muscle-cells, which, indeed, they most resemble (His); by others as 
connective-tissue cells (Waldeyer, Henle, and Kolliker). On the surface of the 
organ this tissue is much condensed, and forms a layer composed of short connec- 
tive-tissue fibres, with fusiform cells between them. This was formerly regarded 
as a distinct fibrous covering, and was termed the tunica albuginea, but is nothing 
more than a condensed layer of the stroma of the ovary. 
Graafian Follicles or Vesicles (jolliculi oophori vesiculori [Graafi]) (Figs. 1105 and 
1106).-Upon making a section of an ovary numerous round transparent vesicles 
of various sizes are to be seen; they are the Graafian vesicles or ovisacs containing 
the ova. Immediately beneath the superficial covering is a layer of stroma, in 
which are a large number of minute vesicles of uniform size, about of an 
inch in diameter. These are the Graafian vesicles in their earliest condition, and 
the layer where they are found has been termed the cortical layer. They are 
especially numerous in the ovary of the young child. After puberty and during the 
whole of the child-bearing period large and mature, or almost mature, Graafian 
vesicles are also found in the cortical 
layer in small numbers, and also 
corpora lutea, the remains of vesicles 
which have burst and are undergoing 
atrophy and absorption. Beneath 
this superficial stratum other large 
and mature Graafian vesicles are 
Ovum. 
Granular zone. 
Peritoneum. 
Fig. 1105.-Section of the ovary. 1, outer covering; 
1', attached border; 2, central stroma; 3, peripheral 
stroma; 4. blood-vessels; 5, Graafian follicles in their 
earliest stage; 6, 7, 8, more advanced follicles; 9, an almost 
mature follicle; 9', follicle from which the ovum has 
escaped; 10, corpus luteum. (After Schron.) 
Stroma of the ovary 
with blood vessels. 
Membrana 
granulosa. 
Coats of the 
Graafian vesicle 
Fig. 1106.-Section of the Graafian vesicle. 
(After von Baer.) 
found embedded in the ovarian stroma. These increase in size as they recede 
from the surface toward a highly vascular stroma in the centre of the organ, 
termed the medullary substance (zona vasculosa [Waldeyeri\). This stroma forms 
the tissue of the hilum by which the ovary is attached, and through which the 
blood-vessels enter; it does not contain any Graafian vesicles. 
The larger Graafian follicles consist of an external fi bro-vascular coat connected 
with the surrounding stroma of the ovary by a network of blood-vessels; and an 
internal coat, named the ovicapsule, which is lined by a layer of nucleated cells, 
called the membrana granulosa. The fluid contained in the interior of the vesicles 
is transparent and albuminous, and in it is suspended the ovum. In that part of 
the mature Graafian vesicle which is nearest the surface of the ovary the cells 
of the membrana granulosa are collected into a mass which projects into the 
cavity of the vesicle. This is termed the discus proligerus, and in this the ovum 
is embedded. 
The ova are formed from the germinal epithelium on the surface of the ovary. THE DESCENT OE THE OVARY 
1503 
This becomes thickened, and in it are seen some cells which are larger and more 
rounded than the rest; these are termed the primordial ova. The germinal epi- 
thelium grows downward in the form of tubes or columns, termed the egg tubes 
of Pfliiger, into the ovarian stroma, which grows outward between the tubes, and 
ultimately cuts them off from the germinal epithelium. These tubes are further 
subdivided into rounded nests or groups each containing a primordial ovum which 
undergoes further development and growth, while the surrounding cells of the nest 
form the epithelium of the Graafian follicle. 
The development and maturation of the Graafian vesicles and ova continue 
uninterruptedly from puberty to the end of the fruitful period of woman's life, 
while their formation commences before birth. Before puberty the ovaries are 
small, the Graafian vesicles contained in them are disposed in a comparatively 
thick layer in the cortical substance; here they present the appearance of a large 
number of minute closed vesicles, constituting the early condition of the Graafian 
vesicle; many, however, never attain full development, but shrink and disappear. 
At puberty the ovaries enlarge and become more vascular, the Graafian vesicles 
are developed in greater abundance, and their ova are capable of fecundation. 
Discharge of the Ovum.-The Graafian vesicles, after gradually approaching 
the surface of the ovary, burst; the ovum and fluid contents of the vesicles are 
liberated, and escape on the exterior of the ovary, passing thence into the Fallopian 
tube. This is effected either by application of the tube to the ovary, or by a 
curling upward of the fimbriated extremity, so that the ovum is caught as it falls. 
In the foetus the ovaries are situated, like the testes, in the lumbar region, near 
the kidneys. They may be distinguished from those bodies at an early period by 
their elongated and flattened form, and by their position; which is at first oblique 
and then nearly transverse. They gradually descend into the pelvis. 
The Round Ligament (p. 1491). 
Vessels and Nerves.-The arteries of the ovaries (Figs. 1100 and 1104) are the 
ovarian from the aorta, corresponding to the spermatic arteries in the male. The 
ovarian artery on each side enters the pelvis in the fold of broad ligament known 
as the suspensory ligament of the ovary and enters the attached border, or hilum, 
of the ovary. The ovarian vessels anastomose about the hilum with branches of 
the uterine artery. The veins follow the course of the arteries; they form a plexus 
near the ovary, the pampiniform plexus, corresponding to a like structure near the 
male testicle. The lymphatics (Figs. 1101 and 1102) terminate in the glands to 
the corresponding side of the aorta, and they anastomose in their course with 
trunks from the uterine fundus and Fallopian tube. The nerves come from the 
ovarian plexus, which is a continuation of the renal plexus along the ovarian artery, 
and from the aortic plexus. 
Surgical Anatomy of the Appendages.-Extra-uterine pregnancy most commonly occurs 
in the ampulla of the tube. The product of the conception may escape through the ostium 
abdominale or the walls of the tube may rupture, a violent hemorrhage resulting. 
Pelvic peritonitis is a not uncommon sequence of tubal disease. Salpingitis is inflammation 
of the mucous coat of the tube-interstitial salpingitis of the middle coat, perisalpingitis of the 
peritoneal coat. 
If inflammation closes the uterine and the abdominal ends of the tube, mucus gathers and dis- 
tends the tube {hydrosalpinx'). If purulent matter gathers, the condition is known as pyosalpinx. 
An ovary may fail to descend and remain well above the pelvic brim; it may prolapse into 
Douglas's pouch; it may enter the sac of a hernia; it may inflame; a tumor or cyst may arise from 
it. A solid tumor of the ovary may be a fibroma, a sarcoma, or a carcinoma. " Cysts may orig- 
inate in any part of the tubo-ovarian structure; as the cortical, medullary, or parenchymatous 
portions of the ovary; in the structure between the tube and ovary known as the Rosenmuller 
organ or parovarian structures; and in the hydatid of Morgagni."1 Cysts may be simple, pro- 
liferating, or dermoid; unilocular or multilocular. Glandular proliferous cysts, papillary pro- 
1 Text-book of Gynecology. By E. E. Montgomery. 1504 
THE FEMALE ORGANS OF GENERATION 
liferous cysts, dermoid cysts, and parovarian cysts may attain a large or even an enormous size. 
The operation for the removal of an ovarian cyst is one of the most successful of the major 
procedures of surgery. 
THE MAMMARY GLAND (MAMMA) (Figs. 1107, 1108, 1109, 1110). 
The breasts, mammary glands or mammae secrete the milk, and are accessory 
glands of the generative system. They develop fully in the female, but remain 
permanently rudimentary in the male. There are two of these glands, and 
they are situated in the superficial fascia of the anterior portion of the thorax. 
Between the two glands and in front of the sternum is a groove, the bosom. 
Description of a Well-developed Breast.-Each gland appears as a hemispher- 
ical body projecting from the front of the thorax beneath the skin and lying over 
a portion of the Pectoralis major muscle and a smaller portion of the Serratus 
magnus muscle. The hemispherical projection extends usually from the margin 
of the sternum to the axilla and from the level of the second rib to the level of 
the sixth rib, or from the third rib to the seventh rib, but this does not represent 
the real size of the gland. The gland is much larger than this, being rendered 
so by tails or prolongations of breast tissue, which will be described later (p. 1505). 
The Nipple (papilla mammae) (Figs. 1107, 1108, 1109, anti 1110).-The nipple 
projects from a little below and to the median side of the summit of the hemi- 
sphere at or above the level of the fifth rib, and is covered with thin skin. The 
right nipple may not exactly correspond in situation and direction to the left 
nipple. Die nipple varies considerably in height and shape. In the virgin it is 
usually cylindrical and 'is directed forward and slightly upward and outward. 
The apex of the nipple is rendered rough by fissures (Fig. 1107), it exhibits a 
depression in which are the openings of the milk ducts (Fig. 1109), and its cir- 
cumference is thrown into concentric ridges (Fig. 1109). The nipple is surrounded 
by a darker circular wrinkled area, the areola (areola mammae) (Figs. 1107 and 
1108), in which are sweat-glands and on which are twelve or fifteen small 
rounded elevations. These elevations are caused by cutaneous sebaceous glands 
which in structure represent a transition between sebaceous and mammary glands. 
They are probably rudimentary portions of the mammary gland and are known 
as the glands of Montgomery (glandulae areolares) (Fig. 1109). The color of the 
nipple and areola varies with the complexion of the individual. In brunettes it is 
darker than in blondes. The usual color of the nipple in a young woman is rosy- 
pink, the areola being of a darker shade. During the early months of pregnancy 
the nipple and areola become dark brown in color, the areola becomes larger in 
circumference and the glands of Montgomery increase in size (Fig. 1110). The 
nipple contains non-striated muscle and mechanical irritation or sexual excitement 
makes it stiff and erect. The skin covering the breast is clear, soft, and delicate, 
and subcutaneous veins are often visible. The skin of the nipple and areola is 
particularly delicate. 
Variations in the Mammae.--Before puberty the glands are small, of the infantile 
type, grow slowly, and differ but slightly from the male organs. The nipple is 
small and flat and pale. At puberty the increase in the size of the breast is rapid 
and considerable, due to growth of gland tissue and of subcutaneous fat. During 
pregnancy the breasts enlarge greatly and remain very large throughout lactation. 
This enlargement is due to new gland tissue and increased vascularity. Numerous 
blue veins are visible in the skin, the areola darkens, and the glands of Mont- 
gomery enlarge (Fig. 1110). During lactation the associated lymphatic glands may 
enlarge (A. Marmaduke Sheild). After the termination of lactation the breasts 
diminish in size. They do not become as small as the virgin breast, are apt to lose 
their hemispherical outlines, and cease to be soft. They droop as flaccid pendulous THE MAMMARY GLAND 
1505 
masses, the subcutaneous fat is largely gone, and the outlines of the lobular breast 
tissue can be seen and felt. The nipple is long and hangs down like a teat. At 
the menopause the breast usually shrinks. In some cases, however, it actually 
increases in size. In such a case, although the gland atrophies, there is an exten- 
sive deposit of fat. In old age the glands undergo atrophy and largely disappear, 
the skin is flabby and thrown into wrinkles, and the breasts contain very little 
glandular structure, and are hard from the presence of fibrous tissue. The nipples 
become pigmented and corrugated. Women vary greatly in the development of 
the breasts. In some women they are large, firm, and well proportioned; in others 
they are small, flat, or atrophy occurs in the course of certain bodily diseases, as 
phthisis, and certain mental diseases, as melancholia. If the ovaries are ill- 
developed the breasts remain flat and small. In newly married women, even 
though pregnancy does not exist, the breasts often develop decidedly and rapidly. 
The outline and direction of the breast and also of the nipple may be altered by 
corsets. The left mamma is usually somewhat larger than the right. 
.Nipple. 
■Areola. 
Fat. 
Lactiferous 
duct. 
Lobule unravelled. 
''Ampulla. 
Lobule. 
Loculi in connective tissue. 
Fig. 1107. Dissection of the lower half of the female breast during the period of lactation. (From Luschka.) 
One gland or both glands may be entirely absent, the nipple being also absent. 
One or both glands may be absent, one or both nipples being present. When there 
is only one nipple, it is apt to be the left. The term polymazia (mammae acces- 
soriae muliebris) means the presence of supernumerary breasts, with or without 
nipples. Polythelia means the presence of supernumerary nipples, the associated 
glandular structure being rudimentary. There may be one, two, or several super- 
numerary breasts, and when more than one exists, are usually asymmetrical. If 
one is functionally active, it enlarges during pregnancy and furnishes milk. 
Supernumerary mammae may secrete milk or may be without function. The 
most common situation is on the part of the chest below and to the inner side of 
the normally placed gland. They may also exist in the axilla, the abdomen, the 
groin, the back, and the thigh. Many cases of supposed supernumerary glands 
have been really instances in which moles, warts, or sebaceous cysts have been 
mistaken for breast tissue, but some cases are undoubted. 1506 
THE FEMALE ORGANS OF GENERATION 
Prolongations of Mammary Tissue.-As previously stated, the outlines of 
the breast are not regular, but here and there tails, prolongations,or cusps come off 
CLAVICLE 
FIRST 
RIB 
PECTORALIS MAJOR- 
SKIN 
SECOND 
RIB 
PECTORALIS 
MINOR 
INTERCOSTALES 
SHEATH OF PEC- 
TORALIS MAJOR 
FIBROUS SEPTUM 
GLAND SUBSTANCE- 
THIRD RIB 
ADIPOSE TISSUE 
•AREOLAR TISSUE 
.SUPERFICIAL 
FASCIA 
AREOLA- 
FOURTH RIB 
N I PPLE- 
LUNG 
ADIPOSE TISSUE 
HORIZONTAL PLANE 
OF NIPPLE 
-FIFTH RIB 
SIXTH RIB 
Fig. 1108.-Right breast in sagittal section, inner surface of outer segment. (Testut.) 
from and are true portions of the gland. Two or even more prolongations pass to 
the edge of the sternum; others pass toward the axilla, the clavicle, and the origin 
SECONDARY AREOLA 
AREOLA 
LARGE 
SEBACEOUS 
GLAN DS 
CONCENTRIC 
RI DGES 
SKIN OF 
BREAST' 
Fig. 1109.-Nipple and areola of a virgin. (Testut.) 
Fig. 1110.-Nipple and areolae of a preg- 
nant woman. (Testut.) 
of the external oblique muscle from the ribs. Underneath the mammary gland 
prolongations of mammary tissue penetrate the pectoral fascia (Heidenhain). THE MAMMARY GLAND 
1507 
If one of the glandular cusps is of considerable size it is called an outlying 
lobule. 
Structure of Mammary Gland and Nipple(Figs. 1107 and 1108).-The glands of 
the bre&sticorpus mammae) rest by a smooth posterior surface upon the loose pectoral 
fascia, which fastens the breast to the muscle beneath, but so loosely that the breast 
is movable. The mamma consists of gland-tissue; of fibrous tissue, connecting its 
lobes, of fatty tissue in the intervals between the lobes, of retinacula, and of skin. 
The gland-tissue, when freed from fibrous tissue and fat, is of a pale reddish color, 
firm in texture, in general circular in form, with prolongations here and there, flat- 
tened from before backward, thicker in the centre than at the circumference, and 
presenting several inequalities on its surface, especially in front. On the anterior 
surface there are many irregular elevated processes with deep spaces between 
them. From the summits of the elevations connective-tissue strands (retinacula 
cutis) pass to the true skin. The glandular structure consists of numerous lobes 
(Join mammae), and these are composed of lobules (lobuli mammae), connected 
together by areolar tissue, blood-vessels, and ducts. The smallest lobules con- 
sist of a cluster of rounded alveoli (Fig. 1107), which open into the smallest 
branches of the excretory ducts; these ducts, uniting, form larger ducts, which 
terminate in single canals. Each canal is called a lactiferous, galactophorus or 
mammillary duct (ductus lactvjerus) (Fig. 1107). Each lobe possesses one lac- 
tiferous duct. This passes to the apex of the lobe and then into the nipple. 
The lactiferous ducts are white and cord-like, and contrast with the yellowish- 
red tissue of the gland itself. The number of excretory ducts varies from fifteen 
to twenty. They converge toward the areola, beneath which each duct forms 
a spindle-shaped dilatation, the ampulla (sinus lactijerans) (Fig. 1107). The 
ampullae serve as reservoirs for the milk. At the base of the nipple the ducts 
become contracted and pursue a straight course to its summit, perforating it by 
separate orifices considerably narrower than the ducts themselves. Each orifice 
(porus lactijerus) is the orifice of a tube which drains an individual lobe. The 
ducts are composed of areolar tissue, with longitudinal and transverse elastic 
fibres; muscular fibres are entirely absent; their mucous lining is continuous, at 
the point of the nipple, with the integument. The epithelium of the mammary 
gland differs according to the state of activity of the organ. In the gland of a woman 
who is not pregnant or nursing the alveoli are very small and solid, being filled 
with a mass of granular polyhedral cells. During pregnancy the alveoli enlarge 
and the cells undergo rapid multiplication. At the commencement of lactation 
the cells in the centre of an alveolus undergo fatty degeneration, and are elim- 
inated in the first milk as colostrum-corpuscles. The peripheral cells of the alveolus 
remain, and form a single layer of granular, short columnar cells lining the limit- 
ing membrana propria. The single nucleus of each cell divides and forms two. 
In the protoplasm, especially in the end of the cells toward the alveolus, 
diops of fat appear, and the nucleus toward this end of the cell also becomes 
fatty. 
The end of the cell toward the alveolus breaks down, and the liberated mate- 
rial constitutes " the albuminous ingredients of the milk, while the drops of fat 
become the milk-globules. The portion of the cell which remains forms new 
cytoplasm, and the same process is repeated over and over again. The cells 
also secrete water and the salts which are found in the milk."1 
The fibrous tissue (Fig. 1108) invests the entire surface of the breast, and sends 
down septa between its lobes, connecting them together. 
The fatty tissue (Figs. 1107 and 1108) surrounds the surface of the gland and 
occupies the interval between its lobes. It usually exists in considerable abun- 
1 Human Physiology. By Joseph Howard Raymond. 1508 
THE FEMALE ORGANS OF GENERATION 
dance, and determines the form and size of the gland. There is no fat immediately 
beneath the areola and nipple. 
Fig. 1111.-The lymphatic vessels of the anterior surface of the bieast; the subareolar plexus and the 
trunks which run from it. (Sappey.) 
DELTA-PECTORAL 
HUMERAL CHAIN 
HUMERAL 
CHAIN 
SUBCLAVIAN 
MAMMARY LYMPHATIC 
ENDING IN SUB- 
CLAVIAN GLANDS 
CENTRAL' 
GROUP 
SCAPULAR' 
CHAIN 
THORACIC 
"CHAIN 
THORACIC5 
CHAIN 
MAMMARY COL- 
LECTING TRUNKS 
THORACIC. 
CHAIN 
SUBAREOLAR 
PLEXUS 
CUTANEOUS COLLECTING 
TRUNK FROM THE - 
THORACIC WALL 
CUTANEOUS COL- 
LECTING TRUNKS 
COLLECTING TRUNKS 
PASSING TO INTERNAL 
MAMMARY GLANDS 
Fig. 1112.-Lymphatics of the breast and axillary glands. (Poirier and Charpy.) 
Vessels and Nerves.-The arteries supplying the mammary gland are derived 
from the perforating branches of the internal mammary, long thoracic branches of the THE MAMMARY GLAND 
1509 
axillary, and branches from the intercostals. The veins describe an anastomotic 
circle around the base of the nipple, called by Haller the circulus venosus. From 
this large branches transmit the blood to the circumference of the gland and end 
in the axillary and internal mammary veins. The lymphatics of the mammary 
gland (Figs. 1111 and 1112) and mammary region have been previously described 
(pp. 812, 813, and 814). The nerves are derived from the fourth, fifth, and sixth 
intercostal nerves, and sympathetic filaments from the dorsal cord pass to the breast 
along the branches of the intercostal nerves. 
Surgical Anatomy.-Occasionally the mammary gland undergoes enormous hypertrophy. 
This may occur at any age, even in the virgin. The physiological enlargement of puberty may 
become excessive or the physiological enlargement of pregnancy and lactation may continue 
and increase after the termination of lactation. The chief elements in the enlargement are fat 
and connective tissue, and it is doubtful if there is extensive reproduction of glandular tissue. 
Abscess of the breast may occur at any age, but is most common by far in nursing women. 
The portals are opened to infection by a crack in the nipple and bacteria are carried inward 
by the lymph-vessels. In some cases the pus gathers beneath the skin (supra-mammary abscess'), 
in others in the breast tissue (intra-mammary abscess'). In rare cases pus gathers beneath the 
breast (retro-mammary abscess). In intra-mammary abscess the pus burrows through the 
fibrous septa or fascia and forms numerous channels, and such a channel is constricted at the 
point where it passes through fascia or a fibrous septum, as an hour-glass is constricted. 
In every patient suffering from abscess the nipple should be examined for a sore or crack, and 
the area when found should be treated antiseptically. A supra-mammary abscess should be 
opened by an incision radiating from the nipple. 
In intra-mammary abscess follow the advice of Sheild: open the abscess by an incision radiating 
from the nipple, insert the index finger, and when possible pass it to the bottom of the abscess 
and carry the tip from the depths of the abscess to as near the surface as possible. At this point 
make a counter opening. The finger breaks down septa which cause constriction and thus con- 
verts the tracking sinuses into one large cavity.1 Drain by tubes. 
A retro-mammary abscess is opened by an incision, following the outline of the breast at the 
thoraco-mammary junction, the finger being pushed through the incision and up under the gland. 
Tuberculosis of the breast may occur, and if it does, cold abscess is apt to form. The best 
treatment is removal of the gland and the associated lymph glands. 
Chronic mastitis is a condition of mammary fibrosis, most common in neurotic single women, 
and apt to be associated with ovarian or uterine disease. 
Malignant dermatitis or Paget's disease of the nipple is a chronic condition consisting of 
epithelial proliferation, induration, desquamation, and ulceration, and it is apt to be followed 
by epithelioma. 
Chancre of the nipple is occasionally met with. 
Secondary and tertiary syphilitic lesions are seen upon the skin of the breast, the nipple, and 
the areola. 
Cysts and tumors are common in the breast. 
There may be cystic degeneration of the gland in women near the menopause (involution 
cysts); a lacteal cyst; a hydatid cyst; an adenoma may become cystic. 
The nipple may suffer from epithelioma, myoma, myxoma, angioma, papilloma, or fibroma. 
The innocent tumors of the breast are fibro-adenoma, cystic adenoma, myxoma, and angioma. 
The skin of the breast may suffer from any form of growth or cyst which could arise from 
the skin of another part. Malignant tumors of the glandular structure are ten times as frequent 
as innocent tumors. Sarcoma is rare; carcinoma is very common. 
Carcinoma of the breast has occupied much of the attention of surgeons during recent years. 
The old operation was uniformly followed by recurrence. The modern radical operation has 
been evolved from the studies of Moore, the younger Gross, Heidenhain, Stiles, Banks, Halsted, 
and others. The modern operation always removes at least the skin and subcutaneous tissue 
over the hemispherical portion of the breast, the outlying lobules of the breast, the pectoral fascia, 
and the sternal portion of the great Pectoral muscle, the lymphatic tracts from the breast, the 
lymphatic glands and cellular tissue from the axilla, and from beneath the latissimus dorsi muscle. 
The pectoral fascia and the sternal portion of the great Pectoral muscle must come away in every 
case, because breast tissue may pass through the fascia. The entire breast must be removed, 
because even in a recent case the entire breast is regarded as infected. The clavicular portion 
of the great Pectoral muscle is anatomically distinct from the sternal portion and its removal is 
not imperative. Some operators remove the lesser Pectoral muscle. To leave it is of no value to 
the arm, and it frequently causes an annoying rigid band anterior to the axilla. To take it away 
1 Diseases of the Breast. By A. Marmaduke Sheild. THE FEMALE ORGANS OF GENERATION 
1510 
gives ready access to the axillary vessels at a desirable point above. The sheath of the axillary 
vein should be removed with the glands and cellular tissue of the axilla. The glands receiving 
lymph from the cancerous area must be removed, of course. In view of the fact that in an 
undetermined percentage of cases a lymph tract passes direct to the subclavian glands, it is 
evident that these glands may become infected by this route instead of, as is more usual, secondarily 
to axillary infection; hence it seems wiser in every case to remove the cellular tissue and glands 
from the subclavian triangle. All of these structures should be removed as one piece, in order 
to avoid cutting across lymph tracts and flooding the wound with carcinoma cells which might 
adhere, grow, and reproduce cancer. 
Halsted's operation is the method adopted by most surgeons. The wound cannot be com- 
pletely closed, and the raw spot is covered at once or later with Thiersch skin grafts. (For sur- 
gical considerations regarding the lymphatics in mammary carcinoma see page 814.) 
The Male Breast (mamma virilis).-The male breast is a small flat struc- 
ture, consisting chiefly of connective tissue, but containing some branched tubules. 
Under normal circumstances it remains permanently of the infantile type. It 
possesses a nipple which is much smaller than that of the female breast, and 
which usually lies over the fourth intercostal space, but may lie over the fourth or 
fifth rib. The nipples of the two sides are rarely placed quite symmetrically. 
Accessory glands and accessory nipples are as common among males as females. 
The male breast may exhibit some evidence of temporary functional activity at birth 
and at puberty. Cases have been recorded of actual lactation by the male breast. 
Surgical Anatomy.-The male breasts may undergo enormous hypertrophy (gynaecomazid). 
In these cases the penis is often small and the testicles may be atrophied. The breasts may 
be absent in the male. Disease of the male breast is not nearly so frequent as disease of the 
female breast. The organ may be the seat of syphilis, tuberculosis, acute or chronic mastitis, 
abscess or tumor. A number of cases of cancer of the male breast have been recorded. THE SURGICAL ANATOMY OF INGUINAL 
HERNIA AND FEMORAL HERNIA. 
Dissection (Fig. 288).-For dissection of the parts concerned in inguinal hernia a male 
subject, free from fat, should always be selected. The body should be placed in the supine 
position, the abdomen and pelvis raised by means of blocks placed beneath them, and the lower 
extremities rotated outward, so as to make the parts as tense as possible. If the abdominal walls 
are flaccid, the cavity of the abdomen should be inflated through an aperture made at the umbil- 
icus. An incision should be made along the middle line from a little below the umbilicus to 
the symphysis pubis, and continued along the front of the scrotum, and a second incision from 
the anterior superior spine of the ilium to just below the umbilicus. These incisions should 
divide the integument, and the triangular-shaped flap included between them should be reflected 
downward and outward, when the superficial fascia will be exposed. 
The Superficial Fascia of the Abdomen (p. 433).-This, over the greater part of 
the abdominal wall, consists of a single layer of fascia, which contains a variable 
amount of fat; but as it approaches the groin it is easily divisible into two layers, 
between which are found the superficial vessels and nerves and the superficial 
inguinal lymphatic glands. 
The Superficial Layer of the Superficial Fascia or the Fascia of Camper is thick, 
areolar in texture, containing adipose tissue in its meshes, the quantity of which 
varies in different subjects. Below, it passes over Poupart's ligament, and is con- 
tinuous with the outer layer of the superficial fascia of the thigh. In the male this 
fascia is continued over the penis and over the outer surface of the cord to the 
scrotum, where it helps to form the dartos. As it passes to the penis, and over the 
cord to the scrotum it changes its character, becoming thin, destitute of adipose 
tissue, and of a pale reddish color; and in the scrotum it acquires some involuntary 
muscular fibres. From the scrotum it may be traced backward, to be continuous 
with the superficial fascia of the perinreum. In the female this fascia is continued 
into the labia majora. 
The hypogastric branch of the ilio-hypogastric nerve perforates the aponeurosis 
of the External oblique muscle about an inch above and a little to the outer side of 
the external abdominal ring, and is distributed to the integument of the hypogas- 
tric region. 
The ilio-inguinal nerve escapes at the external abdominal ring, and is distributed 
to the integument of the upper and inner part of the thigh, to the scrotum in the 
male and to the labium in the female. 
The superficial epigastric artery arises from the femoral about half an inch 
below Poupart's ligament, and, passing through the saphenous opening in the fascia 
lata, ascends on to the abdomen, in the superficial fascia covering the External 
oblique muscle, nearly as high as the umbilicus. It distributes branches to the 
superficial inguinal lymphatic glands, the superficial fascia, and the integument, 
anastomosing with branches of the deep epigastric and internal mammary 
arteries. 
The superficial circumflex iliac artery, the smallest of the cutaneous branches, 
arises close to the preceding, and, piercing the fascia lata, runs outward, parallel 
with Poupart's ligament, as far as the crest of the ilium, dividing into branches 
which supply the superficial inguinal lymphatic glands, the superficial fascia, and 
1511 1512 
THE SURGICAL ANATOMY OF HERNIA 
the integument, anastomosing with the deep circumflex iliac and with the gluteal 
and external circumflex arteries. 
POUPART'S 
LIGAMENT 
INTERCOLUMNAR 
FIBRES 
FEMORAL 
RING" 
EXTERNAL 
ABDOMINAL 
RING 
GIM BE R NAT'S. 
LIGAMENT 
SAPHENOUS. 
OPENING 
FEMORAL 
VEIN 
CRUS 
SUPERIOR 
LONG- 
SAPHENOUS 
VEIN 
Fig. 1113.-Right external abdominal ring and saphenous opening in the male. (Spalteholz.) 
EXTERNAL OBLIQUE 
(reflected inward) 
EXTERNAL OBLIQUE 
(reflected downward) 
POSTERIOR WALL OF 
INGUINAL CANAL 
INTERNAL ORIGIN 
OF CRENASTER 
Fig. 1114.-Right ingminal canal in the male. Second layer viewed from in front. (Spalteholz.) APONEUROSIS OF THE EXTERNAL OBLIQUE MUSCLE 
1513 
The superficial external pudic (superior) artery arises from the inner side of 
the femoral artery close to the preceding vessels, and, after passing through the 
saphenous opening, courses inward across the spermatic cord, to be distributed to 
the integument on the lower part of the abdomen, the penis and scrotum in the male, 
and the labium in the female, anastomosing with branches of the internal pudic. 
The Superficial Veins.-The veins accompanying these superficial vessels are 
usually much larger than the arteries; they terminate in the internal saphenous vein. 
The superficial inguinal lymphatic glands are placed immediately beneath the 
integument, are of large size, and vary from ten to twenty in number (p. 793). 
INTERNAL OBLIQUE 
(reflected inward) 
EXTERNAL OBLIQUE 
(reflected inward) 
INTERNAL 
OBLIQUE 
EXTERNAL 
OBLIQUE" 
(reflected 
downward) 
POSTERIOR 
WALL 
TRIANGU LAR 
'fascia 
Fig. 1115.-The right inguinal canal in the male. Third layer viewed from in front. (Spalteholz.) 
The Deep Layer of the Superficial Fascia, the Fascia of Scarpa or the Fascia of Cooper 
(p. 433) is thinner and more membranous in character than the superficial layer. 
In the middle line it is intimately adherent to the linea alba; above, it is continuous 
with the superficial fascia over the rest of the trunk; below, it blends with the fascia 
lata of the thigh a little below Poupart's ligament; below and internally, in the male, 
it is continued over the penis and over the outer surface of the cord to the scrotum, 
where it helps to form the dartos. From the scrotum it may be traced backward 
to be continuous with the base of the triangular ligament of the urethra. In the 
female it is continuous with the labia majora. 
The scrotum is a cutaneous pouch which contains the testes and part of the 
spermatic cords, and into which an inguinal hernia frequently descends. 
The Aponeurosis of the External Oblique Muscle (Fig. 1113).-This is a thin 
but strong membranous aponeurosis, the fibres of which are directed obliquely 
downward and inward. That portion of the aponeurosis which extends between 1514 
THE SURGICAL ANATOMY OF HERNIA 
the anterior superior spine of the ilium and the spine of the os pubis is a broad 
band, folded inward and continuous below with the fascia lata; it is called Poupart's 
ligament (Figs. 289, 1113, 1116, 1117, 1119, 1124, 1125). The portion which is 
reflected from Poupart's ligament at the spine of the os pubis, along the pectineal 
line, is called Gimbernat's ligament (Fig. 297, 340, 1113, 1124, 1125). A thin fibrous 
band extends from the inner end of Poupart's ligament and Gimbernat's ligament 
upward and inward behind the inner pillar of the external ring to the anterior 
layer of the rectus sheath. The fibres diverge as they ascend. This band is 
known as the triangular fascia or Colles's fascia or the triangular ligament of Colles 
(Figs. 1115 and 1119). 
The External or Superficial Abdominal Ring (annulus inguinalis subcutaneus) 
(Figs. 289 and 1113).-Just above and to the outer side of the crest of the os pubis 
an interval is seen in the aponeurosis of the External oblique, called the external 
abdominal ring. This aperture is oblique in direction, somewhat triangular in 
form, and corresponds with the course of the fibres of the aponeurosis. It usually 
measures from base to apex about an inch, and transversely about half an inch. 
It is bounded below by the crest of the os pubis; above, by a series of curved 
fibres, the intercolumnar fibres, which pass across the upper angle of the ring, so as 
to increase its strength; and on either side by the margins of the opening in the 
aponeurosis, which are called the columns or pillars of the ring. 
The External Pillar, which at the same time is inferior (crus inferius), from the 
obliquity of its direction, is the stronger; it is formed by that portion of Poupart's 
ligament which is inserted into the spine of the os pubis; it is curved, so as to form 
a kind of groove, upon which the spermatic cord rests. 
The Internal or Superior Pillar (crus superius) is a broad, thin, flat band, which 
is attached to the front of the body of the os pubis, interlacing with its fellow of 
the opposite side in front of the symphysis pubis, that of the right side being 
superficial. 
The external abdominal ring gives passage to the spermatic cord in the male 
and round ligament in the female; it is much larger in men than in women, on 
account of the large size of the spermatic cord, hence the great frequency of inguinal 
hernia in men. 
The Intercolumnar Fibres (fibrae intercrurales) (Fig. 1113) are a series of curved 
tendinous fibres which arch across the lower part of the aponeurosis of the Exter- 
nal oblique. They have received their name from stretching across between the 
two pillars of the external ring; they increase the strength of the lower part of the 
aponeurosis and prevent the divergence of the pillars from one another. They 
are thickest below, where they arise from Poupart's ligament, and they are 
inserted into the linea alba, describing a curve, with the convexity downward. 
They are much thicker and stronger at the outer angle of the external ring than 
internally, and are more strongly developed in the male than in the female. 
These intercolumnar fibres, as they pass across the external abdominal ring, are 
themselves connected together by delicate fibrous tissue, thus forming a fascia 
which, as it is attached to the pillars of the ring, covers it in, and is called the 
intercolumnar fascia. This intercolumnar fascia is continued downward as a 
tubular prolongation around the outer surface of the cord and testis, and encloses 
them in a distinct sheath; hence, it is also called the external spermatic fascia. 
The sac of an inguinal hernia in passing through the external abdominal ring 
receives an investment from the intercolumnar fascia. 
If the finger is introduced a short distance into the external ring and the limb 
is then extended and rotated outward, the aponeurosis of the External oblique, 
together with the iliac portion of the fascia lata, will be felt to become tense and 
the external ring much contracted; if the limb is, on the contrary, flexed upon the 
pelvis and rotated inward, this aponeurosis will become lax, and the external ring THE TRIANGULAR FASCIA OF THE ABDOMEN 
1515 
sufficiently enlarged to admit the finger with comparative ease; hence the patient 
should always be put in the latter position when the taxis is applied for the reduc- 
tion of an inguinal hernia, in order that the abdominal walls may be relaxed as 
much as possible. 
The aponeurosis of the External oblique should be removed by dividing it across in the same 
direction as the external incisions, and reflecting it downward and outward; great care is requisite 
in separating it from the aponeurosis of the muscle beneath. The lower part of the Internal 
oblique and the Cremaster are then exposed, together with the inguinal canal, which contains 
the spermatic cord (Fig. 1116). The mode of insertion of Poupart's and Gimbernat's ligaments 
into the os pubis should also be examined. 
Poupart's Ligament (lig amentum inguinale [Pouparti]) (Figs. 289,1113,1116,1117, 
1119,1124, and 1125) or the crural arch is the lower border of the aponeurosis of the 
External oblique muscle, which extends from the anterior superior spine of the ilium 
to the spine of the os pubis. From this latter point it is reflected outward to be 
attached to the pectineal line for about half an inch, forming Gimbernat's ligament. 
Its general direction is curved down- 
ward toward the thigh, where it is con- 
tinuous with the fascia lata. Its outer 
half is rounded and oblique in direc- 
tion; its inner half gradually widens at 
its attachment to the os pubis, is more 
horizontal in direction, and lies be- 
neath the spermatic cord. 
Gimbernat's Ligament (lig amentum 
lacunare [Gimbernati]) (Figs. 289, 297, 
340, 1113, 1124, and 1125) is that por- 
tion of the aponeurosis of the External 
oblique muscle which is reflected up- 
ward and outward from the spine of 
the os pubis to be inserted into the 
pectineal line. It is about half an 
inch in length, larger in the male than 
in the female, almost horizontal in 
direction in the erect posture, and of a 
triangular form, with the base directed 
outward. Its base or outer margin is 
concave, thin, and sharp, and lies in 
contact with the femoral sheath, form- 
ing the inner boundary of the femoral 
ring (Fig. 1124). Its apex corresponds 
to the spine of the os pubis. Its pos- 
terior margin is attached to the pec- 
tineal line, and is continuous with the 
pubic portion of the fascia lata. Its anterior margin is continuous with Poupart's 
ligament. 
The Triangular Fascia of the Abdomen, Colles's Fascia or the Triangular Ligament 
of Colles (ligamentum inguinale reflexum [Collesi]) (Fig. 1115, 1116, and 1119) is a 
band of tendinous fibres, of a triangular shape, which is attached by its apex to 
the inner end of Poupart's ligament and to Gimbernat's ligament. It passes 
inward beneath the spermatic cord, and expands into a somewhat fan-shaped 
fascia, lying behind the inner pillar of the external abdominal ring and in front 
of the conjoined tendon, and interlaces with the ligament of the other side at the 
linea alba in the anterior layer of the sheath of the Rectus muscle. 
Fig. 1115.-Inguinal hernia. Dissection showing the 
Internal oblique and Cremaster. THE SURGICAL ANATOMY OF HERNIA 
1516 
The Ligament of Cooper.-See Fig. 297 and p. 437. 
The Internal Oblique Muscle (Figs. 1114, 1115, aiid 1116) has been previously 
described (p. 437). The part which is now exposed is partly muscular and partly 
tendinous in structure. Those fibres which arise from Poupart's ligament, few in 
number and paler in color than the rest, arch downward and inward across the 
spermatic cord, and, becoming tendinous, are inserted, conjointly with those of 
the Transversalis, into the crest of the os pubis and pectineal line, forming what 
is known as the conjoined tendon of the Internal oblique and Transversalis (Figs. 
1116 and 1117). This tendon is inserted immediately behind the inguinal canal 
and external abdominal ring, serving to protect what would otherwise be a weak 
point in the abdominal wall. The conjoined tendon is sometimes divided into 
an outer and an inner portion, the former being called the ligament of Hessel- 
bach (Jigamentum interfoveolare) (Fig. 292), and the latter the ligament of Henle 
(Fig. 292). Sometimes the conjoined tendon is insufficient to resist the pressure 
from within, and is carried forward in front of the protrusion through the exter- 
nal ring, forming one of the coverings of direct inguinal hernia, or the hernia 
forces its way through the fibres of the conjoined tendon. 
The Cremaster (Figs. 1114 and 1116) is derived from the lower margin of the 
Internal oblique, of which muscle it is in reality a portion. It is a thin muscular 
layer composed of a number of fasciculi. It arises by a thick external bundle of 
fibres from the upper portion of Poupart's ligament, being connected with the 
Internal oblique muscle and also occasionally with the Transversalis. It arises 
also by a thin inner bundle of fibres from the anterior layer of the rectus 
sheath. 
The thick bundle of origin is on the lateral surface; the thin bundle is on the 
medial surface of the spermatic cord. The Cremaster passes along with the 
spermatic cord, and descends with it through the external ring. Upon the front and 
sides of the cord both bundles spread out upon the vaginal tunic of the testicle 
and epididymis, and form a series of loops which differ in thickness and length 
in different subjects. These loops are united together by areolar tissue, and 
form a thin covering over the cord and testis, the cremasteric fascia (jascia 
cr emaster ica). 
It will be observed that the Cremaster is a separated portion of the Internal 
oblique. This fact affords an easy explanation of the manner in which the testicle 
and cord are invested by this muscle. At an early period of foetal life the testis is 
placed at the lower and back part of the abdominal cavity, but during its descent 
toward the scrotum, which takes place before birth, it passes beneath the arched 
border of the Internal oblique. In its passage beneath this muscle some fibres 
are derived from its lower part, which accompany the testicle and cord into the 
scrotum. 
It occasionally happens that the loops of the Cremaster surround the cord, some 
lying behind as well as in front. It is probable that under these circumstances 
the testis in its descent passes through, instead of beneath, the fibres of the Internal 
oblique. 
In the descent of an oblique inguinal hernia, which takes the same course as 
the spermatic cord, the Cremaster muscle forms one of its coverings. This muscle 
becomes largely developed in cases of hydrocele and large old scrotal herniae. No 
such muscle exists in the female, but an analogous structure is developed in those 
cases where an oblique inguinal hernia descends beneath the margin of the Internal 
oblique. 
The Internal oblique should be detached from Poupart's ligament, separated from the Trans- 
versalis to the same extent as in the previous incisions, and reflected inward on to the sheath 
of the Rectus (Fig. 1117). The deep circumflex iliac vessels, which lie between these two muscles, 
form a valuable guide to their separation. THE INGUINAL OR SPERMATIC CANAL 
1517 
The Transversalis Muscle (Figs. 1115 and 1117) has been previously described 
(p. 442). The part which is now exposed is partly muscular and partly tendinous 
in structure; it arises from the outer third of Poupart's ligament, its fibres curve 
downward and inward, and are inserted, together with those of the Internal 
oblique, into the lower part of the linea alba, into the crest of the os pubis and 
the pectineal line, forming what is known as the conjoined tendon of the Internal 
oblique and Transversalis (Figs. 1116and 1117). The falx aponeurotica [inguinalis] 
is a collection of fibres of tendinous consistence in the inner side of the Trans- 
versalis insertion. Between the lower border of this muscle and Poupart's 
ligament a space is left in which is seen the transversalis fascia. 
The Inguinal or Spermatic Canal (canalis inguinalis) (Figs. 1114, 1115, and 1117) 
contains the spermatic cord in the male and the round ligament in the female. It 
is an oblique canal, about an inch ami a half in length, directed downward and 
inward and placed parallel with, and a little above, Poupart's ligament. It com- 
mences above at the internal or deep abdominal ring, which is the point where 
Internal 
abdominal ring. 
Epigastric artery. 
Fig. 1117.-Inguinal hernia. Dissection showing the Transversalis muscle, the transversalis fascia, 
and the internal abdominal ring. 
the cord enters the inguinal canal, and terminates below at the external or super- 
ficial ring. It is bounded, in front, by the integument and superficial fascia, by 
the aponeurosis of the External oblique throughout its whole length, and by the 
Internal oblique for its outer third; behind, by the triangular fascia, the conjoined 
tendon of the Internal oblique and Transversalis, transversalis fascia, and the 
subperitoneal fat and peritoneum; above, by the arched fibres of the Internal 
oblique and Transversalis; below, by the union of the transversalis fascia with 
Poupart's ligament. That form of hernia in which the intestine follows the course 
of the spermatic cord along the inguinal canal is called oblique inguinal hernia. 
On the posterior wall of the inguinal canal is seen the band of fibres known as 
the ligament of Hesselbach (ligamentum interjoveolare [Hesselbaehi\) (Fig. 292). 
It is placed in front of the deep epigastric artery. The fibres come from the 
external portion of the lower fibres of the conjoined tendon (Fig. 1116) and pass 1518 
THE SURGICAL ANATOMY OF HERNIA 
downward for a distance, some of them then passing outward and upward, some 
of them downward and inward to the inner surface of Poupart's ligament. 
The Transversalis Fascia (Figs. 297, 1117, and 1125) is a thin aponeurotic mem- 
brane which lies between the inner surface of the Transversalis muscle and the 
peritoneum. It forms part of the general layer of fascia which lines the interior 
of the abdominal and pelvic cavities, and is directly continuous with the iliac 
and pelvic fasciae. 
In the inguinal region the transversalis fascia is thick and dense in structure, 
and joined by fibres from the aponeurosis of the Transversalis muscle; but it 
becomes thin and cellular as it ascends to the Diaphragm. Below, it has the 
following attachments; external to the femoral vessels it is connected to the 
posterior margin of Poupart's ligament, and is there continuous with the iliac 
fascia. Internal to the vessels it is thin, and attached to the os pubis and pectineal 
line behind the conjoined tendon, with which it is united; and, corresponding to 
the points where the femoral vessels pass into the thigh, this fascia descends in 
front of them, forming the anterior wall of the femoral sheath. The spermatic cord 
in the male and the round ligament in the female pass through this fascia; the 
point where they pass through is called the internal or deep abdominal ring. This 
opening is not visible externally, owing to a prolongation of the transversalis fascia 
on the structures forming the infundibuliform fascia. 
The Internal or Deep Abdominal Ring (annulus inguinalis abdominal is) (Figs. 297 
and 1117) is situated in the transversalis fascia, midway between the anterior superior 
spine of the ilium and symphysis pubis, and about half an inch above Poupart's 
ligament. It is of an oval form, its long diameter being directed upward and 
downward; it varies in size in different subjects, and is much larger in the male 
than in the female. It is bounded above and externally by the arched fibres of 
the Transversalis muscle, below and internally by the deep epigastric vessels. It 
transmits the spermatic cord in the male and the round ligament in the female. 
From its circumference, a thin, funnel-shaped membrane, the infundibuliform fascia, 
is continued around the cord and testis, enclosing them in a distinct pouch (Fig. 
1117). When the sac of an oblique inguinal hernia passes through the internal or 
deep abdominal ring, the infundibuliform fascia constitutes one of its coverings. 
The Subperitoneal Areolar Tissue or the Fascia Propria of Cooper.-Between the 
transversalis fascia and the peritoneum is a quantity of loose areolar tissue. In 
some subjects it is of considerable thickness and loaded with adipose tissue. 
Opposite the internal ring it is continued around the surface of the cord, forming 
a loose sheath for it. 
The Deep Epigastic Artery (Figs. 292 and 1118) arises from the external iliac 
artery a few lines above Poupart's ligament. It at first descends to reach this liga- 
ment, and then ascends obliquely along the inner margin of the internal or deep 
abdominal ring, lying between the transversalis fascia and the peritoneum, and 
passing upward pierces the transversalis fascia and enters the sheath of the Rectus 
muscle by passing over the semilunar fold of Douglas. Consequently the deep 
epigastric artery bears a very important relation to the internal abdominal ring 
as it passes obliquely upward and inward from its origin from the external iliac. 
In this part of its course it lies along the lower and inner margin of the internal 
ring and beneath the commencement of the spermatic cord. At its commence- 
ment it is crossed by the vas deferens in the male and by the round ligament in 
the female. 
The Peritoneum (Fig. 1118), corresponding to the inner surface of the internal 
ring, presents a well-marked depression, the depth of which varies in different 
subjects. A thin fibrous band is continued from it along the front of the cord 
for a variable distance, and becomes ultimately lost, the ligament of Cloquet. 
This is the remains of the pouch of peritoneum which, in the foetus, precedes THE PERITONEUM 
1519 
the cord and testis into the scrotum, the obliteration of which commences soon 
after birth. In some cases the fibrous band can only be traced a short distance, 
but occasionally it may be followed, as a fine cord, as far as the upper end of the 
tunica vaginalis. Sometimes the tube of peritoneum is closed only at intervals 
and presents a sacculated appearance, or a single pouch may extend along the 
whole length of the cord, which may be closed above, or the pouch may be directly 
continuous with the peritoneum by an opening at its upper part. 
In the female foetus the peritoneum is also prolonged in the form of a tubular 
process for a short distance into the inguinal canal. This process is called the 
canal of Nuck. It is generally obliterated in the adult, but sometimes it remains 
pervious even in advanced life- 
JV. iliacus. 
External 
inguinal 
fossa. 
Crural 
nerve. 
External 
iliac 
artery. 
External 
iliac 
vein. 
Femoral 
fossa. 
Superior vesical 
artery. 
fUiddle inguinal 
fossa. 
Internal inguinal 
fossa. 
Fig. 1118.- Posterior view of the anterior abdominal wall in its lower half. The peritoneum is in place, 
and the various cords are shining through. (After Joessel.) 
In order to understand the relation of the peritoneum to inguinal hernia, it is 
necessary to view the anterior abdominal wall from its internal aspect, when it will 
be seen as shown in Fig. 1118. Between the upper margin of the front of the 
pelvis and the umbilicus, the peritoneum, when viewed from behind, will be seen 
to be raised into five vertical folds, with intervening depressions, by more or less 
prominent bands which converge to the umbilicus. One of these is situated in the 
median line, and is caused by the urachus, the remnant of the allantois; it extends 
from the summit of the bladder to the umbilicus. The fold of peritoneum covering 
it is known as the fold of the urachus or the plica urachi (plica umbilicalis media). 
On either side of this is a prominent band, caused by the obliterated hypogastric 
artery, which extends from the side of the bladder obliquely upward and inward 
to the umbilicus. This is covered by a fold of peritoneum which is known as the 1520 
THE SURGICAL ANATOMY OF HERNIA 
hypogastric fold or the plica hypogastrica (plica umbilicalis lateralis). To either 
side of these three cords is the deep epigastric artery, which ascends obliquely 
upward and inward from a point midway between the symphysis pubis and the 
anterior superior spine of the ilium to the semilunar fold of Douglas, in front of 
which it disappears. It is covered by a fold of peritoneum which is known as the 
plica epigastrica. Between these raised folds are depressions of the peritoneum, 
constituting so-called fossae. The most internal, between the plica urachi and the 
plica hypogastrica, is known as the internal inguinal fossa (jovea supravesicalis). 
The middle one is situated between the plica hypogastrica and the plica epigas- 
trica, and is termed the middle inguinal fossa (jovea inguinalis mesialis). The 
external one is external to the plica epigastrica, and is known as the external 
inguinal fossa (jorea inguinalis lateralis). Occasionally the deep epigastric artery 
corresponds in position to the obliterated hypogastric artery, and then there is but 
one fold on each side of the middle line, and the two external fossae are merged 
into one. In the usual condition of the parts the floor of the external inguinal 
fossa corresponds to the internal abdominal ring, and into this fossa an oblique 
inguinal hernia descends. To the inner side of the plica epigastrica are the 
two internal fossae, and through either of these a direct hernia may descend, as 
will be explained in the sequel (p. 1523). The whole of this space, that is to 
say, the space between the deep epigastric artery, the margin of the Rectus and 
Poupart's ligament, is commonly known as Hesselbach's triangle. These three 
depressions or fossae are situated above the level of Poupart's ligament, and in 
addition to them is another below the ligament, corresponding to the position of 
the femoral ring, and into which a femoral hernia descends. 
INGUINAL HERNIA. 
Inguinal hernia is that form of protrusion which makes its way through the 
abdomen in the inguinal region. 
There are two principal varieties of inguinal hernia-external or oblique, and 
internal or direct. 
External or oblique inguinal hernia, the more frequent of the two, takes the 
same course as the spermatic cord. It is called external from the neck of the sac 
being on the outer or iliac side of the deep epigastric artery. 
Internal or direct inguinal hernia does not follow the same course as the cord, 
but protrudes through the abdominal wall on the inner or pubic side of the deep 
epigastric artery. 
Oblique Inguinal Hernia. 
In oblique inguinal hernia (Fig. 1118) the intestine or omentum escapes from the 
abdominal cavity at the internal ring. Before it is a pouch of peritoneum, which 
forms the hernial sac (Fig. 1119, .4). This pouch of peritoneum is invested by the 
subserous areolar tissue, and is enclosed in the infundibuliform process of the trans- 
versalis fascia, which it receives as it enters the inguinal canal. In passing along the 
inguinal canal the hernia displaces upward the arched fibres of the Transversalis and 
Internal oblique muscles, and is imperfectly surrounded by the fibres of the Cre- 
master muscles, the coat being completed by the cremasteric fascia. It then passes 
along the front of the cord, and escapes from the inguinal canal at the external 
ring, receiving an investment from the intercolumnar fascia. Lastly, it descends 
into the scrotum, receiving coverings from the superficial fascia and the integument. 
The coverings of this form of hernia, after it has passed through the external 
ring, are, from without inward, the integument, superficial fascia, intercolumnar OBLIQUE INGUINAL HERNIA 
1521 
fascia, Cremaster muscle ami fascia, infundibuliform fascia, subserous areolar 
tissue, and peritoneum. 
This form of hernia lies in front of the vessels of the spermatic cord and seldom 
extends below the testis, on account of the intimate adhesion of the coverings 
of the cord to the tunica vaginalis (Fig. 1120, A). 
The seat of stricture in a strangulated oblique inguinal hernia is either at the 
external ring, in the inguinal canal, caused by the fibres of the Internal oblique 
or Transversal is; or at the internal ring, most frequently in the latter situation. 
If it is situated at the external ring, the division of a few fibres at one point of 
its circumference is all that is necessary for the replacement of the hernia. If 
in the inguinal canal or at the internal ring, it may be necessary to divide the 
Fig. 1119.-Oblique inguinal hernia, showing its various coverings. (From a preparation in the 
Museum of the Royal College of Surgeons.) 
aponeurosis of the External oblique so as to lay open the inguinal canal. In 
dividing the stricture the direction of the incision should be upward. 
When the hernia passes along the inguinal canal and escapes from the external 
ring into the scrotum, the condition is called complete oblique inguinal or scrotal 
hernia (Fig. 1120, A). If the hernia does not escape from the external ring, but is 
retained in the inguinal canal, the condition is called incomplete inguinal hernia or 
bubonocele. In each of these cases the coverings which invest the intestine or 
omentum will depend upon the extent to which it descends in the inguinal canal. 
There are some other varieties of oblique inguinal hernia depending upon con- 
genital defects in the processus vaginalis. The testicle in its descent from, the 
abdomen into the scrotum is preceded by a pouch of peritoneum, which about 1522 
THE SURGICAL ANATOMY OE HERNIA 
the period of birth becomes shut off from the general peritoneal cavity by a closure 
of that portion of the pouch which extends from the internal abdominal ring to 
Sac of hernia. 
Tunica 
•vaginalis. 
Tunica 
vaginalis.- 
A. Common scrotal hernia. 
B Congenital hernia. 
Sac of 
hernia. 
■Tunica vaginalis. 
Sac of hernia. 
Tunica 
'vaginalis. 
C. Infantile hernia. 
D. Encysted hernia. 
Tunica vaginalis. 
■Sac of hernia. 
E Hernia into the funicular process 
near the upper part of the testicle, the lower portion of the pouch remaining per- 
sistent as the tunica vaginalis. It would appear that this closure commences at 
Fig. 1120.-Varieties of oblique inguinal hernia DIRECT INGUINAL HERNIA 
1523 
two points-viz., at the internal abdominal ring and at the top of the epididymis 
-and gradually extends until, in the normal condition, the whole of the inter- 
vening portion is converted into a fibrous cord. From failure in the completion 
of this process variations in the relation of the hernial protrusion to the testicle 
and tunica vaginalis are produced, which constitute distinct varieties of inguinal 
hernia, and which have received separate names and are of surgical importance. 
These are congenital, infantile, encysted, and hernia of the funicular process. 
Congenital Hernia (Fig. 1120, B).-Where the congenital pouch of peritoneum 
which precedes the cord and testis in its descent remains patent throughout and 
is unclosed at any point, the cavity of the tunica vaginalis communicates directly 
with the cavity of the peritoneum. The intestine-descends along this pouch into 
the cavity of the tunica vaginalis, which constitutes the sac of the hernia, and the 
gut lies in contact with the testicle. 
Infantile and Encysted Hernia.-Where the congenital pouch of peritoneum 
is occluded at the internal ring only, but remains patent throughout the rest of 
its extent, two varieties of oblique inguinal hernia may be produced, which have 
received the names of infantile and encysted hernia. In the infantile form (Fig. 
1120, 0) the septum which closed the congenital sac above and the peritoneum 
in its immediate neighborhood yields and forms a sac, which descends behind the 
tunica vaginalis, so that in front of the bowel there are three layers of perito- 
neum, the two layers of the tunica vaginalis and the layer of the proper hernial 
sac. In the encysted form (Fig. 1120, D) yielding occurs in the same position as 
in the infantile form-namely, at the occluded spot in the pouch-and a sac forms 
which projects into and not behind the tunica vaginalis, as in the infantile form, 
and thus it constitutes a sac within a sac, so that in front of the bowel there are two 
layers of peritoneum-one layer of the tunica vaginalis and one of true hernial sac. 
Hernia into the Funicular Process (Fig. 1120, E).-Where the congenital 
pouch of peritoneum is occluded at the lower point only-that is, just above the 
testicle-the intestine descends into the pouch of peritoneum as far as the testicle, 
but is prevented from entering the sac of the tunica vaginalis by the septum which 
has formed between it and the pouch, so that it resembles the congenital form in 
all respects, except that, instead of enveloping the testicle, that body can be felt 
below the rupture. 
Direct Inguinal Hernia. 
In direct inguinal hernia the protrusion makes its way through some part of 
the abdominal wall internal to the epigastric artery. 
At the lower part of the abdominal wall is a triangular space, Hesselbach's 
triangle, bounded externally by the deep epigastric artery, internally by the 
margin of the Rectus muscle, below by Poupart's ligament (Fig. 1118). The con- 
joined tendon is stretched across the inner two-thirds of this space, the remaining 
portion of the space having only the subperitoneal areolar tissue and the trans- 
versalis fascia between the peritoneum and the aponeurosis of the External oblique 
muscle. 
In some cases the hernial protrusion escapes from the abdomen on the outer 
side of the conjoined tendon, pushing before it the peritoneum, the subserous 
areolar tissue, and the transversalis fascia. It then enters the inguinal canal, 
passing along nearly its whole length, and finally emerges from the external ring, 
receiving an investment from the intercolumnar fascia. The coverings of this 
form of hernia are precisely similar to those investing the oblique form, with the 
insignificant difference that the infundibuliform fascia is replaced by a portion 
derived from the general layer of the transversalis fascia. 
In other cases-and this is the more frequent variety-the hernia is either forced 
through the fibres of the conjoined tendon or the tendon is gradually distended in THE SURGICAL ANATOMY OF HERNIA 
1524 
front of it so as to form a complete investment for it. The intestine then enters 
the lower end of the inguinal canal, escapes at the external ring lying on the 
inner side of the cord, and receives additional coverings from the superficial fascia 
and the integument. This form of hernia has the same coverings as the oblique 
variety, excepting that the conjoined tendon is substituted for the Cremaster, and 
the infundibuliform fascia is replaced by a portion derived from the general layer 
of the transversalis fascia. 
The difference between the position of the neck of the sac in these two forms 
of direct inguinal hernia has been referred, with some probability, to a difference 
in the relative positions of the obliterated hypogastric artery and the deep epi- 
gastric artery. When the course of the obliterated hypogastric artery corre- 
sponds pretty nearly with that of the deep epigastric the projection of these 
arteries toward the cavity of the abdomen produces two fossae in the peritoneum. 
The bottom of the external fossa of the peritoneum corresponds to the position of 
the internal abdominal ring, and a hernia which distends and pushes out the peri- 
toneum lining this fossa is an oblique hernia. When, on the other hand, the 
obliterated hypogastric artery lies considerably to the inner side of the deep epi- 
gastric artery, corresponding to the outer margin of the conjoined tendon, it divides 
the triangle of Hesselbach into two parts, so that three depressions will be seen on 
the inner surface of the lower part of the abdominal wall-viz., an external one on 
the outer side of the deep epigastric artery; a middle one, between the deep epi- 
gastric and the obliterated hypogastric arteries; and an internal one, on the inner 
side of the obliterated hypogastric artery (pp. 1519 and 1520). In such a case 
a hernia may distend and push out the peritoneum forming the bottom of either 
fossa. These fossae are the inguinal fossae. When the hernia distends and 
pushes out the peritoneum forming the bottom of the external fossa, it is an 
oblique or external inguinal hernia. 
When the hernia distends and pushes out the peritoneum forming the bottom 
of either the middle or the internal fossa, it is a direct or internal hernia. 
The anatomical difference between these two forms of direct or internal inguinal 
hernia is that, wrhen the hernia protrudes through the middle fossa-that is, 
the fossa between the deep epigastric and the obliterated hypogastric arteries- 
it will enter the upper part of the inguinal canal; consequently its coverings will be 
the same as those of an oblique hernia, with the insignificant difference that the 
infundibuliform fascia is replaced by a portion derived from the general layer of 
the transversalis fascia, whereas when the hernia protrudes through the internal 
fossa it is either forced through the fibres of the conjoined tendon or the tendon is 
gradually distended in front of it so as to form a complete investment for it. The 
intestine then enters the lower part of the inguinal canal, and escapes from the 
external abdominal ring lying on the inner side of the cord. 
This form of hernia has the same coverings as the oblique variety, excepting 
that the conjoined tendon is substituted for the Cremaster, and the infundibuli- 
form fascia is replaced by a portion derived from the general layer of the fascia 
transversalis. 
The seat of stricture in strangulation in both varieties of direct hernia is most 
frequently at the neck of the sac or at the external ring. In that form of hernia 
which perforates the conjoined tendon it not unfrequently occurs at the edges of 
the fissure through which the gut passes. In dividing the stricture the incision 
should in all cases be directed upward.1 
If the hernial protrusion passes into the inguinal canal, but does not escape 
1 In all cases of inguinal hernia, whether oblique or direct, it is proper to divide the stricture directly upward: 
the reason of this is obvious, for by cutting in this direction the incision is made parallel to the deep epigastric 
artery-either external to it in the oblique variety, or internal to it in the direct form of hernia-and thus all 
chance of wounding the vessel is avoided. If the incision was made outward, the artery might be divided if the 
hernia was direct; and if made inward, the vessel would stand an equal chance of injury if the case was one of 
oblique inguinal hernia.-Ed. of 15th English edition. FEMORAL HERNIA 
1525 
from the external abdominal ring, it forms what is called incomplete direct hernia. 
This form of hernia is usually of small size, and in corpulent persons is very 
difficult of detection. 
Direct inguinal hernia is of much less frequent occurrence than the oblique, 
their comparative frequency being, according to Cloquet, as one to five. It occurs 
far more frequently in men than in women, on account of the larger size of the 
external ring in the former sex. It differs from the oblique in its smaller size and 
globular form, dependent most probably on the resistance offered to its progress 
by the transversalis fascia and conjoined tendon. It differs also in its position, 
being placed over the os pubis and not in the course of the inguinal canal. The 
deep epigastric artery runs on the outer or iliac side of the neck of the sac, and the 
spermatic cord along its external and posterior side, not directly behind it, as in 
oblique inguinal hernia. 
FEMORAL HERNIA 
The dissection of the parts comprised in the anatomy of femoral hernia should be performed, 
if possible, upon a female subject free from fat. The subject should lie upon the back; a block 
is first placed under the pelvis, the thigh everted, and the knees slightly bent and retained in 
this position. An incision should then be made from the anterior superior spinous process of 
the ilium along Poupart's ligament to the symphysis pubis; a second incision should be carried 
transversely across the thigh about six inches beneath the preceding; and these are to be con- 
nected together by a vertical one carried along the inner side of the thigh (Fig. 340). These 
several incisions should divide merely the integument; this is to be reflected outward, when the 
superficial fascia will be exposed. 
The Superficial Fascia forms a continuous layer over the whole of the thigh, 
consisting of areolar tissue, containing in its meshes much fat, and capable of being 
separated into two or more layers, between which are found the superficial vessels 
and nerves. It varies in thickness in different parts of the limb. In the groin 
it is thick, and the two layers are separated from one another by the superficial 
inguinal lymphatic glands, the internal saphenous vein, and several smaller 
vessels. One of these layers, the superficial, is continuous with the superficial 
fascia of the abdomen. 
The superficial layer should be detached by dividing it across in the same direction as the 
external incisions; its removal will be facilitated by commencing at the lower and inner angle of 
the space, detaching it at first from the front of the internal saphenous vein, and dissecting it 
off from the anterior surface of that vessel and its tributaries; it should then be reflected out- 
ward in the same manner as the integument. The cutaneous vessels and nerves and superficial 
inguinal glands are then exposed, lying upon the deep layer of the superficial fascia. These are 
the internal saphenous vein and the superficial epigastric, superficial circumflex iliac, and super- 
ficial external pudic vessels, as well as numerous lymphatics, ascending with the saphenous vein 
to the inguinal glands. 
The internal or long saphenous vein (Figs. 1121, 1122, and 1123) ascends along 
the inner side of the thigh, and, passing through the saphenous opening in the 
fascia lata, terminates in the femoral vein about an inch and a half below Poupart's 
ligament (Fig. 1113). This vein receives at the saphenous opening the superficial 
epigastric, the superficial circumflex iliac, and the superficial external pudic veins. 
The superficial external pudic artery (superior) arises from the inner side of 
the femoral artery, and, after passing through the saphenous opening, courses 
inward across the spermatic cord, to be distributed to the integument on the 
lower part of the abdomen, the penis and scrotum in the male and the labium in 
the female, anastomosing with branches of the internal pudic. 
The superficial epigastric artery arises from the femoral about half an inch 
below Poupart's ligament, and, passing through the saphenous opening in the 
fascia lata, ascends on to the abdomen, in the superficial fascia covering the 
External oblique muscle, nearly as high as the umbilicus. It distributes branches 1526 
THE SURGICAL ANATOMY OF HERNIA 
to the superficial inguinal lymphatic glands, the superficial fascia, and the integu- 
ment, anastomosing with branches of the deep epigastric and internal mammary 
arteries. 
The superficial circumflex iliac artery, the smallest of the cutaneous branches, 
arises close to the preceding, and, piercing the fascia lata, runs outward, parallel 
with Poupart's ligament, as far as the crest of the ilium, dividing into branches 
which supply the superficial inguinal lymphatic glands, the superficial fascia, and 
the integument of the groin, anastomosing with the deep circumflex iliac, and with 
the gluteal and external circumflex arteries. 
The Superficial Veins (Fig. 1121).-The veins accompanying these superficial 
arteries are usually much larger than the arteries; they terminate in the internal 
or long saphenous vein at the saphenous opening. 
The superficial inguinal lymphatic glands.-See p. 793. 
Fig. 1121.-Femoral hernia. Superficial dissection. 
The ilio-inguinal nerve arises from the first lumbar nerve. It escapes at the 
external abdominal ring, and is distributed to the integument of the upper and 
inner part of the thigh-to the scrotum in the male and to the labium in the 
female. The size of this nerve is in inverse proportion to that of the ilio-hypo- 
gastric nerve. Occasionally it is very small, and ends by joining the ilio-hypogastric; 
in such cases a branch of the ilio-hypogastric takes the place of the ilio-inguinal, 
or the latter nerve may be altogether absent. The crural branch of the genito- 
crural nerve passes along the inner margin of the Psoas muscle, beneath Poupart's 
ligament, into the thigh, entering the sheath of the femoral vessels, and lying FEMORAL HERNIA 
1527 
superficial and a little external to the femoral artery. It pierces the anterior layer 
of the sheath of the vessels, and, becoming superficial by passing through the fascia 
lata, it supplies the skin of the anterior aspect of the thigh as far as midway 
between the pelvis and knee. On the front of the thigh it communicates with 
the outer branch of the middle cutaneous nerve, derived from the anterior crural. 
The Deep Layer of the Superficial Fascia is a very thin fibrous layer, best marked 
on the inner side of the long saphenous vein and below Poupart's ligament. It is 
placed beneath the subcutaneous vessels and nerves, and upon the surface of the 
fascia lata, to which it is intimately adherent at the lower margin of Poupart's 
ligament. It covers the saphenous opening in the fascia lata, is closely united to 
its circumference, and is connected to the sheath of the femoral vessels corre- 
Fig. 1122.-Femoral hernia, showing fascia lata and saphenous opening. 
spending to its under surface. The portion of fascia covering this aperture is 
perforated by the internal saphenous vein and by numerous blood- and lymphatic 
vessels; hence it has been termed the cribriform fascia, the openings for these 
vessels having been likened to the holes in a sieve. The cribriform fascia adheres 
closely both to the superficial fascia and to the fascia lata, so that it is described 
by some anatomists as a part of the fascia lata, but it is usually considered*(as in 
this work) as belonging to the superficial fascia. It is not till the cribriform fascia 
has been cleared away that the saphenous opening is seen, so that this opening 
does not in ordinary cases exist naturally, but is the result of dissection (p. 513). A 
femoral hernia in passing through the saphenous opening receives the cribriform 
fascia as one of its coverings. 1528 
THE SURGICAL ANATOMY OF HERNIA 
The deep layer of superficial fascia, together with the cribriform fascia, having 
been removed, the fascia lata is exposed. 
The Fascia Lata has been already described with the muscles of the front of 
the thigh (p. 513). At the upper and inner part of the thigh, a little below 
Poupart's ligament, a large oval-shaped aperture is observed after the superficial 
fascia has been cleared away; it transmits the internal saphenous vein and other 
smaller vessels, and is called the saphenous opening (Fig. 1113). In order the 
more correctlv to consider the mode of formation of this aperture, the fascia lata in 
this part of the thigh is described as consisting of two portions, an iliac portion and 
a pubic portion. 
Fig. 1123.-Femoral hernia. Iliac portion of fascia lata removed, and sheath of femoral vessels and 
femoral canal exposed. 
The iliac portion (Fig. 1122) is all that part of the fascia lata on the outer side of 
the saphenous opening. It is attached externally to the crest of the ilium and its 
anterior superior spine; to the whole length of Poupart's ligament; and to the 
pectineal line in conjunction with Gimbernat's ligament. From the spine of the 
os pubis it is reflected downward and outward, forming an arched margin, the 
outer boundary or falciform process or superior cornu (cornu superius) (Fig. 1122) 
of the saphenous opening. This margin overlies and is adherent to the anterior 
layer of the sheath of the femoral vessels; to its edge is attached the cribriform 
fascia, and below it is continuous with the pubic portion of the fascia lata. 
The pubic portion of the fascia lata or the pectineal fascia (Fig. 1122) is situated 
at the inner side of the saphenous opening; at the lower margin of this aperture 
it is continuous with the iliac portion; traced upward, it covers the surface of 
the Pectineus, Adductor longus, and Gracilis muscles; and, passing behind the FEMORAL HERNIA 
1529 
sheath of the femoral vessels, to which it is loosely united, is continuous with 
the sheath of the Psoas and Iliacus muscles, and is attached above to the ilio- 
pectineal line, where it becomes continuous with the fascia covering the Iliacus 
muscle. From the description it may be observed that the iliac portion of the 
fascia lata passes in front of the femoral vessels and the pubic portion behind 
them, so that an apparent aperture consequently exists between the two, through 
which the internal saphenous vein joins the femoral vein. 
The Saphenous Opening (fossa ovalis) (Figs. 1113, 1121, 1122, and 1123) is an 
oval-shaped aperture measuring about an inch and a half in length and half an 
inch in width. It is situated at the upper and inner parts of the front of the 
thigh, below Poupart's ligament, and is directed obliquely downward and out- 
ward. It is covered by the cribriform fascia fascia cribrosa), a portion of the 
deep layer of the superficial fascia of the thigh, and which extends from the 
falciform margin to the pubic portion of the fascia lata or the pectineal fascia. 
The outer margin of the saphenous opening is of a semilunar form, thin, strong, 
sharply defined, and lies on a plane considerably anterior to the inner margin. 
If this edge is traced upward, it will be seen to form a curved elongated process, 
the falciform process or superior cornu (Fig. 1122), which ascends in front of the 
femoral vessels, and, curving inward, is attached to Poupart's ligament and to the 
spine of the os pubis and pectineal line, where it is continuous with the pubic por- 
tion. If traced downward, it is found continuous with another curved margin, 
the concavity of which is directed upward and inward; this is the inferior cornu 
of the saphenous opening, and is blended w ith the pubic portion of the fascia 
lata covering the Pectineus muscle. 
The inner boundary of the opening (Figs. 1113 and 1122) is on a plane posterior 
to the outer margin and behind the level of the femoral vessels; it is much less 
prominent and defined than the outer, from being stretched over the subjacent 
Pectineus muscle. It is through the saphenous opening that a femoral hernia 
passes after descending along the crural canal. 
If the finger is introduced into the saphenous opening while the limb is moved 
in different directions, the aperture will be found to be greatly constricted on 
extending the limb or rotating it outward, and to be relaxed on flexing the limb 
and inverting it; hence the necessity for placing the limb in the latter position in 
employing the taxis for the reduction of a femoral hernia. 
The iliac portion of the fascia lata, but not its falciform process, should now7 be removed by 
detaching it from the lower margin of Poupart's ligament, carefully dissecting it from the sub- 
jacent structures, and turning it inward, when the sheath of the femoral vessels is exposed, 
descending beneath Poupart's ligament (Fig. 1123). 
Poupart's Ligament (ligamentum inguinale [Pouparti]) (Figs. 289, 1113, 1116, 
1117, 1119,1122, 1123, 1124, and 1125) is the lower border of the aponeurosis 
of the External oblique muscle, which extends from the anterior superior spine 
of the ilium to the spine of the os pubis. From this latter point it is reflected 
outward, to be attached to the pectineal line for about half an inch, forming 
Gimbemat's ligament. Its general direction is curved downward toward the thigh, 
where it is continuous with the fascia lata. Its outer half is rounded and 
oblique in direction. Its inner half gradually widens at its attachment to the 
os pubis, is more horizontal in direction, and lies beneath the spermatic cord. 
Nearly the whole of the space included between Poupart's ligament and the 
innominate bone is filled in by the parts which descend from the abdomen into 
the thigh (Figs. 297, 340, and 1124). The outer half of the space (lacuna muscu- 
lorum) is occupied by the Iliacus and Psoas muscles, together with the external 
cutaneous and anterior crural nerves. The pubic half of the space (lacuna 
vasorum) is occupied by the femoral vessels included in their sheath, a small oval- 
shaped interval existing between the femoral vein and the inner wall of the sheath, 1530 
THE SURGICAL ANATOMY OF HERNIA 
which is occupied merely by a little loose areolar tissue, a few lymphatic vessels, 
and occasionally by a small lymphatic gland; this is the femoral ring, through 
which the gut descends in femoral hernia. The part of Poupart's ligament in 
front of the femoral or crural ring is called the superficial crural arch. 
Gimbernat's Ligament (ligamenturn lacunare [Gimbernati\) (Figs. 297,340, 1113, 
1124, and 1125) is that part of the aponeurosis of the External oblique muscle 
which is reflected backward and outward from the spine of the os pubis, to be 
inserted into the pectineal line. It is about half an inch in length, larger in the 
male than in the female, almost horizontal in direction in the erect posture, and 
of a triangular form, with the base directed outward. Its base or outer margin 
is concave, thin, and sharp, and lies in contact with the femoral sheath. Its 
apex corresponds to the spine of the os pubis. Its posterior margin is attached to 
the pectineal line, and is continuous with the pubic portion of the fascia lata. Its 
anterior margin is continuous with Poupart's ligament. 
External 
cutaneous nerve. 
Poupart's ligament. 
Crural 
branch 
of genito- 
crural. 
Anterior crural. 
Iliac portion of 
fascia lata. 
Sheath of 
vessels. 
Femoral vein. 
Femoral ring. 
Gimbemat's 
ligament. 
U*K '"ORTION OF 
PSOAS 
MAGNUS. 
Femoral artery. 
Fig. 1124.-Structures which pass beneath the crural arch. 
Femoral Sheath (Fig. 1124).-The femoral or crural sheath is a continuation down- 
ward of the fasciae that line the abdomen, the transversalis fascia passing down in 
front of the femoral vessels, and the iliac fascia descending behind them; these 
fasciae are directly continuous on the iliac side of the femoral artery, but a small 
space exists between the femoral vein and the point where they are continuous on 
the pubic side of that vessel,which constitutes the femoral or crural canal (Fig. 1113). 
The femoral sheath is closely adherent to the contained vessels about an inch 
below the saphenous opening, being blended with the areolar sheath of the vessels, 
but opposite Poupart's ligament it is much larger than is required to contain them; 
hence the funnel-shaped form which it presents. The outer border of the sheath FEMORAL HERNIA 
1531 
is perforated by the genito-crural nerve. Its inner border is pierced by the internal 
saphenous vein and numerous lymphatic vessels. In front it is covered by the 
iliac portion of the fascia lata; and behind it is the pubic portion of the same 
fascia. 
If the anterior wall of the sheath is removed (Fig. 1113), the femoral artery and 
vein are seen lying side by side, a thin septum separating the two vessels, while 
another septum may be seen lying just internal to the vein, and cutting off a small 
space between the vein and the inner wall of the sheath. The septa are stretched 
between the anterior and posterior walls of the sheath, so that each vessel is 
enclosed in a separate compartment. The interval left between the vein and the 
inner wall of the sheath is not filled up by any structure, excepting a little loose 
areolar tissue, a few lymphatic vessels, and occasionally by a small lymphatic 
gland; this is the femoral or crural canal (Fig. 1113), through which the intestine 
descends in femoral hernia. 
Deep Crural Arch.-Passing across the front of the femoral sheath on the abdom- 
inal side of Poupart's ligament, and closely connected with it, is a thickened band 
of fibres of the transversalis fascia, called the deep crural arch. It is apparently a 
thickening of the transversalis fascia, joining externally to the centre of Poupart's 
ligament, and arching across the front of the crural sheath, to be inserted by a 
broad attachment into the pectineal line behind the conjoined tendon. In some 
subjects this structure is not very prominently marked, and not infrequently it is 
altogether wanting. The superficial crural arch is the portion of Poupart's liga- 
ment in front of the femoral ring. 
The Femoral or Crural Canal (canalis femoralis) (Figs. 297, 340, and 1113) is the 
narrow interval between the femoral vein and the inner wall of the femoral sheath. 
It exists as a distinct canal only when the sheath has been separated from the vein 
by dissection or by the pressure of a hernia or tumor. Its length is from a quarter 
to half an inch, and it extends from the femoral ring to the upper part of the 
saphenous opening. 
Its anterior wall is very narrow, and formed by a continuation downward of 
the transversalis fascia, under Poupart's ligament, covered by the falciform 
process of the fascia lata. 
Its posterior wall is formed by a continuation downward of the iliac fascia cover- 
ing the pubic portion of the fascia lata. 
Its outer wall is formed by the fibrous septum separating it from the inner side 
of the femoral vein. 
Its inner wall is formed by the junction of the processes of the transversalis 
and iliac fasciae, which form the inner side of the femoral sheath, and lies in 
contact at its commencement with the outer edge of Gimbernat's ligament. 
This canal has two orifices-an upper one, the femoral or crural ring, closed by 
the septum crurale; and a lower one, the saphenous opening, closed by the cribri- 
form fascia. 
The femoral or crural ring (annulus femoralis) (Figs. 1113, 1124, and 1125) is 
the upper opening of the femoral canal, and leads into the cavity of the abdomen. 
It is bounded in front by Poupart's ligament and the deep crural arch; behind, 
by the os pubis, covered by the Pectineus muscle and the pubic portion of the fascia 
lata; internally, by the base of Gimbernat's ligament, the conjoined tendon, the 
transversalis fascia, and the deep crural arch; externally, by the fibrous septum 
lying on the inner side of the femoral vein. The femoral ring is of an oval form; 
its long diameter, directed transversely, measures about half an inch, and it is 
larger in the female than in the male, which is one of the reasons of the greater 
frequency of femoral hernia in the former sex. 
Position of Parts around the Ring.-The spermatic cord in the male and 
round ligament in the female lie immediately above the anterior margin of the 1532 
THE SURGICAL ANATOMY OF HERNIA 
femoral ring, and may be divided in an operation for femoral hernia if the incision 
for the relief of the stricture is not of limited extent. In the female this is of little 
importance, but in the male the spermatic artery and vas deferens may be divided. 
The femoral vein lies on the outer side of the ring. 
The deep epigastric artery in its passage upward and inward from the external 
iliac artery passes across the upper and outer angle of the crural ring, and is 
consequently in danger of being wounded if the stricture is divided in a direction 
upward and outward. 
The communicating branch between the deep epigastric and obturator lies in 
front of the ring. 
The circumference of the ring is thus seen to be bounded by vessels in every 
part, excepting internally and behind (Fig. 1125). It is in the former position that 
the stricture is divided in cases of strangulated femoral hernia. 
The obturator artery (p. 688), when it arises by a common trunk with the deep 
epigastric (p. 689), which occurs once in every three subjects and a half, bears 
a very important relation to the crural ring. In most cases it descends on the 
Fig. 1125.-Hernia. The relations of the femoral and internal abdominal rings, seen from within the 
abdomen. Right side. 
inner side of the external iliac vein to the obturator foramen, and will consequently 
lie on the outer side of the crural ring, where there is no danger of its being 
wounded in the operation for dividing the stricture in femoral hernia (Fig. 427 A, 
p. 689). Occasionally, however, the obturator artery curves along the free margin 
of Gimbernat's ligament in its passage to the obturator foramen; it would conse- 
quently skirt along the greater part of the circumference of the crural ring, and 
could hardly avoid being wounded in the operation (Fig. 427 B, p. 689). 
The Crural Septum or Septum Crurale (septum femorale musculus) (Fig. 297).- 
The femoral ring is closed by a thin process of transversalis fascia containing fat 
and called, by J. Cloquet, the septum crurale. This serves as a barrier to the 
protrusion of a hernia through this part. Its upper surface is slightly concave, 
and supports a small lymphatic gland (Fig. 1125), by which it is separated from 
the subserous areolar tissue and peritoneum. Its under surface is turned toward 
the femoral canal. The septum crurale is perforated by numerous apertures for 
the passage of lymphatic vessels connecting the deep inguinal lymphatic glands 
with those surrounding the external iliac artery. FEMORAL HERNIA 
1533 
The size of the femoral canal, the degree of tension of its orifices, and conse- 
quently the degree of constriction of a hernia, vary according to the position of 
the limb. If the leg and thigh are extended, abducted, or everted, the femoral 
canal and its orifices are rendered tense from the traction on these parts by Pou- 
part's ligament and the fascia lata, as may be ascertained by passing the finger 
along the canal. If, on the contrary, the thigh is flexed upon the pelvis, and at 
the same time adducted and rotated inward, the femoral canal and its orifices 
become considerably relaxed; for this reason the limb should always be placed in 
the latter position when the application of the taxis is made in attempting the 
reduction of a femoral hernia. 
The subperitoneal areolar tissue is continuous with the subserous areolar tissue 
of surrounding parts. It is usually thickest and most fibrous where the iliac ves- 
sels leave the abdominal cavity. It covers over the femoral ring, the small interval 
on the inner side of the femoral vein. In some subjects it contains a considerable 
amount of adipose tissue. In such cases, where it is protruded forward in front 
of the sac of a femoral hernia, it may be mistaken for a portion of omentum. The 
peritoneum lining the portion of the abdominal wall between Poupart's ligament 
and the brim of the pelvis is similar to that lining any other portion of the abdom- 
inal wall, being very thin. Here there is no natural aperture for the escape of 
intestine. 
Descent of the Hernia.-From the preceding description it follows that the 
femoral ring must be a weak point in the abdominal wall; hence it is that when 
violent or long-continued pressure is made upon the abdominal viscera a portion 
of intestine may be forced into it, constituting a femoral hernia; and the changes 
in the tissues of the abdomen which are produced by pregnancy, together with the 
larger size of this aperture in the female, serve to explain the frequency of this 
form of hernia in women. 
When a portion of the intestine passes through the femoral ring, a pouch of 
peritoneum lies before it, which forms what is called the hernial sac; it is cov- 
ered by the subserous areolar tissue, receives an investment from the septum 
crurale, and descends vertically along the crural canal in the inner compartment of 
the sheath of the femoral vessels as far as the saphenous opening; at this point it 
changes its course, being prevented from extending farther down the sheath on 
account of the narrowing of the sheath and its close contact with the vessels, and 
also from the close attachment of the superficial fascia and crural sheath to the 
lower part of the circumference of the saphenous opening; the hernia is conse- 
quently directed forward, pushing before it the cribriform fascia, and then curves 
upward on to the falciform process of the fascia lata and lower part of the tendon 
of the External oblique, being covered by the superficial fascia and integument. 
While the hernia is contained in the femoral canal it is usually of small size, 
owing to the resisting nature of the surrounding parts; but when it has escaped 
from the saphenous opening into the loose areolar tissue of the groin, it becomes 
considerably enlarged. The direction taken by a femoral hernia in its descent is 
at first downward, then forward and upward; this should be borne in mind, as 
in the application of the taxis for the reduction of a femoral hernia pressure should 
be directed in the reverse order. 
Coverings of the Complete Hernia.-The coverings of a femoral hernia, from 
within outward, are-peritoneum, subserous areolar tissue, the septum crurale, 
crural sheath, cribriform fascia, superficial fascia, and integument.1 
1 Sir Astley Cooper has described an investment for femoral hernia, under the name of "fascia propria," lying 
immediately external to the peritoneal sac, but frequently separated from it by more or less adipose tissue. 
Surgically, it is important to remember the existence (at any rate, the occasional existence) of this layer, on 
account of the ease with which an inexperienced operator may mistake the fascia for the peritoneal sac and the 
contained fat for omentum. Anatomically, this fascia appears identical with what is called in the text "sub- 
serous areolar tissue," the areolar tissue being thickened and caused to assume a membranous appearance by 
the pressure of the hernia.-Ed. of 15th English edition. 1534 
THE SURGICAL ANATOMY OF HERNIA 
Varieties of Femoral Hernia.-If the hernia descends along the femoral canal only 
as far as the saphenous opening, and does not escape from this aperture, the con- 
dition is called incomplete femoral hernia. The small size of the protrusion in this 
form of hernia, which is due to the firm and resisting nature of the canal in 
which it is contained, renders it an exceedingly dangerous variety, from the 
extreme difficulty of detecting the existence of the swelling, especially in corpulent 
subjects. The coverings of an incomplete femoral hernia, named from without 
inward,are as follows: the integument, superficial fascia, iliac portion of fascia lata, 
crural sheath, septum crurale, subserous areolar tissue, and peritoneum. When, 
however, the hernia protrudes through the saphenous opening and directs itself 
forward and upward, it forms a complete femoral hernia, the coverings of which 
have been given (p. 1533). Occasionally the hernial sac descends on the iliac 
side of the femoral vessels or in front of these vessels, or even sometimes behind 
them. 
The seat of stricture in a strangulated femoral hernia varies; it may be in the 
peritoneum at the neck of the hernial sac; in the greater number of cases it would 
appear to be at the point of junction of the falciform process of the fascia lata 
with the lunated edge of Gimbernat's ligament, or at the margin of the saphenous 
opening in the thigh. The stricture should in every case be divided in an inward 
direction, or upward and inward, and the extent of the necessary cut in the 
majority of cases is about two or three lines. By these means all vessels or 
other structures of importance in relation with the neck of the hernial sac will 
be avoided. SURGICAL ANATOMY OF THE PERINEUM. 
Dissection.-The student should select a well-developed muscular subject, free from fat, 
and the dissection should be commenced early, in order that the parts may be examined in as 
recent a state as possible. A staff having been introduced into the bladder and the subject 
placed in the position shown in Fig. 1126, the scrotum should be raised upward, and retained in 
that position, and the rectum moderately distended with tow. 
The Perinaeum corresponds to the inferior aperture or outlet of the pelvis. Its 
deep boundaries are, in front, the pubic arch and subpubic ligament; behind, 
the tip of the coccyx; and on each side, the rami of the os pubis and ischium, the 
tuberosities of the ischium, and great sacro-sciatic ligaments. The space included 
by these boundaries is somewhat lozenge-shaped, and is limited on the surface of 
Fig. 1126.-Dissection of perinseum and ischio-rectal region. 
the body by the scrotum in front, by the buttocks behind, and on each side by the 
inner side of the thigh. A line drawn transversely between the anterior parts of 
the tuberosities of the ischium, on each side, in front of the anus, divides this space 
into two portions. The anterior portion contains the penis and urethra, and is 
called the perinaeum proper or genito-urinary region. The posterior portion con- 
tains the termination of the rectum, and is called the ischio-rectal or anal region. 
ISCHIO-RECTAL REGION. 
The ischio-rectal region contains the termination of the rectum and a deep fossa, 
filled with fat, on each side of the intestine, between it and the tuberosity of the 
ischium; this is called the ischio-rectal fossa. 
The ischio-rectal region presents in the middle line the aperture of the anus; 
around this orifice the integument is thrown into numerous folds, which are 
obliterated on distention of the anus. The integument is of a dark color, con- 
tinuous with the mucous membrane of the rectum, and is provided with numerous 
1535 1536 
SURGICAL ANATOMY OF THE PERINEUM 
follicles, which occasionally inflame ami suppurate, ami may be mistaken for 
fistulae. The veins around the margin of the anus are occasionally much dilated, 
forming a number of hard pendent masses, of a dark bluish color, covered partly 
by mucous membrane and partly by the integument. These tumors constitute the 
disease called external piles. 
Dissection (Fig. 1126).-Make an incision through the integument, along the median line, 
from the base of the scrotum to the anterior extremity of the anus: carry it around the margins 
of this aperture to its posterior extremity, and continue it backward to about an inch behind 
the tip of the coccyx. A transverse incision should now be carried across the base of the scrotum, 
joining the anterior extremity of the preceding; a second, carried in the same direction, should 
be made in front of the anus; and a third at the posterior extremity of the first incision. These 
incisions should be sufficiently extensive to enable the dissector to raise the integument from 
the inner side of the thighs. The flaps of skin corresponding to the ischio-rectal region should 
now be removed. In dissecting the integument from this region great care is required, otherwise 
the Corrugator cutis ani and External sphincter will be removed, as they are intimately adherent 
to the skin. 
The Superficial Fascia is exposed on the removal of the skin; it is very thick, 
areolar in texture, and contains much fat in its meshes. In it are found ramifying 
two or three branches of the perforating cutaneous nerve; these turn around the 
inferior border of the Gluteus maximus and are distributed to the integument 
around the anus. 
In this region, and connected with the lower end of the rectum, are four muscles: 
the Corrugator cutis ani; the two Sphincters, External and Internal; and the 
Levator ani. 
These muscles have been already described (p. 449). 
The Ischio-rectal Fossa (fossa ischiorectalis) (Figs. 300 and 304) is situated 
between the end of the rectum and the ischial tuberosity. It is triangular in shape; 
its base, directed to the surface of the body, is formed by the integument of the 
ischio-rectal region; its apex, directed upward, corresponds to the point of division 
of the obturator fascia and the thin membrane given off from it, which covers the 
outer surface of the Levator ani (ischio-rectal or anal fascia). Its dimensions are 
about an inch in breadth at the base and about two inches in depth, being deeper 
behind than in front. It is bounded, internally, by the Sphincter ani, Levator 
ani, and Coccygeus muscles; externally, by the tuberosity of the ischium and the 
obturator fascia, which covers the inner surface of the Obturator interims muscle; 
in front, it is limited by the line of junction of the superficial fascia with the base 
of the triangular ligament; and behind, by the margin of the Gluteus maximus 
muscle and the great sacro-sciatic ligament. This space is filled with a large mass 
of adipose tissue, which explains the frequency with which abscesses in the neigh- 
borhood of the rectum burrow to a considerable depth. 
If the subject has been injected, on placing the finger on the outer wall of this 
fossa the internal pudic artery, with its accompanying veins and the two divisions 
of the nerve, will be felt about an inch and a half above the margin of the ischiatic 
tuberosity, but approaching nearer the surface as they pass forward along the 
inner margin of the pubic arch. These structures are enclosed in a sheath, the 
fascial canal or canal of Alcock (Figs. 304 and 1131), formed by the obturator fascia, 
the pudic nerve lying below the artery and the dorsal nerve of the penis above it. 
Crossing the space transversely, about its centre are the inferior hemorrhoidal 
vessels and nerves, which are distributed to the integument of the anus and to the 
muscles of the lower end of the rectum. These vessels are occasionally of large 
size, and may give rise to troublesome hemorrhage when divided in the operation 
of lithotomy or in that for fistula in ano. At the back part of this space, near 
the coccyx, may be seen a branch of the fourth sacral nerve, and at the forepart of 
the space the superficial perineal vessels and nerves can be seen for a short distance. THE PERINEUM PROPER IN THE MALE 
1537 
THE PERINEUM PROPER IN THE MALE. 
The perineal space is of a triangular form; its deep boundaries are limited, 
laterally, by the rami of the pubic bones and ischia, meeting in front at the pubic 
arch; behind, by an imaginary transverse line extending between the anterior 
parts of the tuberosities of the ischia. The lateral boundaries are, in the adult, 
from three inches to three inches and a half in length, and the base from two to 
three inches and a half in breadth, the average extent of the space being two 
inches and three-quarters. 
The variations in the diameter of this space are of extreme interest in connection with the 
operation of lithotomy and the extraction of a stone from the cavity of the bladder. In those 
cases where the tuberosities of the ischia are near together it would be necessary to make the 
incisions in the lateral operation of lithotomy less oblique than if the tuberosities were widely 
separated, and the perineal space consequently wider. The perinaeum is subdivided by the 
median raphe into two equal parts. Of these, the left is the one in which the operation of lith- 
otomy is performed. 
In the middle line the perinaeum is convex, and corresponds to the bulb of the 
urethra. The skin covering it is of a dark color, thin, freely movable upon the 
subjacent parts, and covered with sharp crisp hairs, which should be removed 
before the dissection of the part is commenced. In front of the anus a prominent 
line commences, the raphg, continuous in front with the raphe of the scrotum. 
The skin of the raphe is adherent to the deep layer of the superficial fascia. 
Upon removing the skin and the superficial layer of the superficial fascia, in the 
manner shown in Fig. 1126, a plane of fascia will be exposed, covering in the 
triangular space and stretching across from one ischio-pubic ramus to the other. 
This is the deep layer of the superficial fascia or fascia of Colles (jascia supcrficialis 
perinael). It has already been described (p. 456). It is a layer of considerable 
strength, and encloses and covers a space in which are contained muscles, vessels, 
and nerves. It is continuous in front with the fascia of the penis and the dartos 
of the scrotum; on each side it is firmly attached to the margin of the ischio-pubic 
ramus and to the tuberosity of the ischium; and posteriorly it curves down behind 
the Transversalis perinaei muscles to join the base of the triangular ligament. 
It is between this layer of fascia and the triangular ligament of the urethra that extravasa- 
tion of urine most frequently takes place in cases of rupture of the urethra. The triangular 
ligament of the urethra (p. 459) is attached to the ischio-pubic rami, and in front to the subpubic 
ligament. It is clear, therefore, that when extravasation of fluid takes place between these 
two layers, it cannot pass backward, because the two layers are continuous with each other 
around the Transversi perinaei muscles: it cannot extend laterally, on account of the connection 
of both these layers to the rami of the os pubis and ischium; it cannot find its way into the pelvis 
because the opening into this cavity is closed by the triangular ligament, and, therefore, so 
long as these two layers remain intact, the only direction in which the fluid can make its way 
is forward into the areolar tissue of the scrotum and penis, and then on to the anterior wall of 
the abdomen. 
When the deep layer of the superficial fascia is removed (Fig. 1127), a space is 
exposed, between this fascia and the triangular ligament, in which are contained the 
superficial perineal vessels and nerves and some of the muscles connected with the 
penis and urethra-viz., in the middle line, the Accelerator urinae; on each side, 
the Erector penis; and behind, the transversus perinaei; together with the crura 
of the corpora cavernosa and the bulb of the corpus spongiosum. Here also is seen 
the central tendinous point of the perinaeum. This is a fibrous point in the middle 
line of the perineum between the urethra and the rectum, being about half an inch 
in front of the anus. At this point four muscles converge and are attached-viz., 
the External sphincter ani, the Accelerator urinae, and the two Transversi perinaei SURGICAL ANATOMY OF THE PERINEUM 
1538 
muscles; so that by the contraction of these muscles, which extend in opposite 
directions, it serves as a fixed point of support. 
The Accelerator urinae, the Erector penis, and the Superficial transversus 
perinaei muscles have been already described (p. 457). They form a triangular 
space (Fig. 1127), bounded, internally, by the Accelerator urinae; externally, by 
the Erector penis; and behind, by the Transversus perinaei. The floor of this 
space is formed by the triangular ligament of the urethra; and running from 
behind forward in it are the superficial perineal vessels and nerves, and the 
transverse perineal artery coursing along the posterior boundary of the space, 
on the Transversus perinaei muscle. 
The Accelerator urinae and Erector penis should now be removed, when the triangular liga- 
ment of the urethra will be exposed, stretching across the front of the outlet of the pelvis. The 
urethra is seen perforating its centre, just behind the bulb; and on each side is the crus penis, 
connecting the corpus cavernosum with the rami of the ischium and os pubis. 
Transrersus perinei 
superficialis.' 
■Superficial perineal artery. 
■Superficial perineal nerve. 
GREAT SACRO* 
SCIATIC LIGAMENT." 
.Internal pudic nerve. 
Internal pudic artery. 
Fig. 1127.-The superficial muscles and vessels of the perinanim. 
The Triangular Ligament or the Deep Perineal Fascia (trigonum urogenitale or 
diaphragma urogenitale) (Figs. 309, 310, and 1128), which has been already 
described (p. 459), consists of two layers, the inferior anterior or superficial layer 
(fascia trigoni urogenitalis inferior) of which is now exposed. It is united to the 
superior or deep layer behind, but is separated in front by a subfascial space in 
which are contained certain structures. 
The inferior layer of the triangular ligament (Figs. 305 and 310) consists of a 
strong fibrous membrane, the fibres of which are disposed transversely, which 
stretches across from one ischio-pubic ramus to the other and completely fills in 
the pubic arch; it is attached in front to the subpubic ligament, except just in the 
centre, where a small interspace is left for the dorsal vein of the penis. In the erect 
position of the body it is almost horizontal. It is perforated by the urethra in the 
middle line, and on each side of the urethral opening by the ducts of Cowper's 
glands and by the arteries of the bulb; in front, and external to this, by the artery THE PERINEUM PROPER IN THE MALE 
1539 
of the corpus cavernosum, immediately before this vessel enters the crus penis. 
Near its apex the ligament is perforated by the termination of the pudic artery and 
by the dorsal nerve of the penis. The apex of the triangular ligament is known as 
the transverse perineal ligament. The crura penis are exposed, lying superficial to 
this ligament. They will be seen to be attached by blunt-pointed processes to the 
rami of the os pubis and ischium, in front of the tuberosities, and passing forward 
and inward, joining to form the body of the penis. In the middle line the bulb and 
corpus spongiosum are exposed by the removal of the Accelerator urinae muscle. 
If the inferior layer of the triangular ligament is detached on either side, 
the deep perineal interspace will be exposed and the following parts will be seen 
between it and the deep layer of the ligament: the subpubic ligament in front, 
close to the symphysis pubis; the dorsal vein of the penis; the membranous por- 
tion of the urethra and the Compressor urethrae muscle; Cowper's glands and 
their ducts; the pudic vessels and the dorsal nerve of the penis; the artery and 
nerve of the bulb and a plexus of veins. 
Anterior layer of 
deep perineal fascia removed, 
showing 
.Internal pudic artery. 
-Artery of the bulb. 
COMPRESSOR URETHRE. 
'Cowper's gland. 
Fig. 1128.-Deep perineal fascia. On the left side the anterior layer has been removed. 
The superior, deep, or posterior layer of the triangular ligament or deep perineal 
fascia (fascia trigoni urogenitalis superior) (Fig. 305) is derived from the obturator 
fascia, and is continuous with it along the pubic arch. Behind, it joins with the 
inferior layer of the triangular ligament, and is continuous with the anal fascia. 
Above it is the prostate gland (Fig. 1129), supported by the anterior fibres of 
the Levator ani, which act as a sling for the gland and form the Levator prostatae 
muscle. The superior layer of the triangular ligament is continuous around the 
anterior free edge of this muscle with the layer of recto-vesical fascia covering 
the prostate gland. The superior layer of the triangular ligament is perforated 
by the urethra. Between the two layers of the triangular ligament are situated 
the membranous part of the urethra, enveloped by the Compressor urethrae 
muscle (Fig. 309); the ducts of Cowper's glands; the arteries to the bulb; the 
pudic vessels and the dorsal nerve of the penis. The membranous part of the 
urethra is about three-quarters of an inch in length, and passes downward and SURGICAL ANATOMY OF THE PERINEUM 
1540 
forward behind the symphysis pubis, from which it is distant about an inch. It 
is the narrowest part of the tube, and is enveloped, as has already been stated, 
by the Compressor urethrae muscle. 
The Compressor urethrae has already been described (p. 460). In addition to 
this muscle, and immediately beneath it, circular muscular fibres surround the 
membranous portion of the urethra from the bulb in front to the prostate behind, 
and are continuous with the muscular fibres of the bladder. These fibres are 
involuntary. 
Cowper's glands (Figs. 303, 1128, and 1129) are situated immediately below 
the membranous portion of the urethra, close behind the bulb, and below the 
artery of the bulb. 
The Pudic Vessels (Figs. 1128 and 1129) and Dorsal Nerve of the Penis (Fig. 310) 
are placed along the inner margin of the pubic arch (p. 1536). 
The Artery of the Bulb (Figs. 1128 and 1129, and p. 691) passes transversely 
inward, from the internal pudic artery (p. 689) along the base of the triangular 
Avtery of corpus cavernosum.. 
Dorsal artery of penis. 
Artery of bulb. 
Internal pudic artery. 
Cowper's gland. 
Fig. 1129.-A view of the position of the viscera at the outlet of the pelvis. 
ligament, between its two layers, accompanied by a branch of the pudic nerve. 
If the superior layer of the triangular ligament is removed and the crus penis of 
one side detached from the bone, the under or perineal surface of the Levator 
ani muscle, covered by the anal fascia, is brought fully into view (Figs. 302, 
303, and 304). This muscle, with the triangular ligament in front and the Coc- 
cygeus and Pyriformis behind, closes the outlet of the pelvis. 
The Levator ani and Coccygeus muscles have already been described (p. 451). 
Position of the Viscera at the Outlet of the Pelvis. Divide the central tendinous point 
of the perinseum, separate the rectum from its connections by dividing the fibres of the Levator 
ani, which descend upon the sides of the prostate gland, and draw the gut backward toward the 
coccyx, when the under surface of the prostate gland, the neck and base of the bladder, the 
vesiculae seminales, and the vasa deferentia will be exposed. 
The Prostate Gland (p. 1129) is a pale, firm, glandular body which is placed 
immediately below the neck of the bladder, around the commencement of the THE PERINEUM PROPER IN THE MALE 
1541 
urethra. It is placed in the pelvic cavity, behind the lower part of the sym- 
physis pubis, above the superior layer of the triangular ligament, and rests upon 
the rectum, through which it may be distinctly felt, especially when enlarged. In 
shape and size it resembles a chestnut. Its base is directed upward toward the 
neck of the bladder. Its apex is directed downward to the deeper layer of the 
triangular ligament, which it touches. 
Its posterior surface is smooth, marked by a slight longitudinal furrow, and rests 
on the second part of the rectum, to which it is connected by areolar tissue. Its 
anterior surface is flattened, marked by a slight longitudinal furrow, and placed 
about three-quarters of an inch below the pubic symphysis. It measures about 
an inch and a half in its transverse diameter at the base, an inch in its antero- 
posterior diameter, and three-quarters of an inch in depth. Hence the greatest 
extent of incision that can be made in it without dividing its substance completely 
across is obliquely backward and outward. This is the direction in which the 
incision is made in it in the lateral operation of lithotomy. The prostate has a 
sheath derived from the recto-vesical fascia (p. 1449). 
Above the prostate a small triangular portion of the bladder is seen (Fig. 1129), 
bounded, in front and below, by the prostate gland; above, by the recto-vesical fold 
of the peritoneum; on each side, by the seminal vesicle and the vas deferens. It is 
separated from direct contact with the rectum by the recto-vesical fascia. The 
relation of this portion of the bladder to the rectum is of extreme interest to the 
surgeon. In cases of retention of urine this portion of the organ is found pro- 
jecting into the rectum, between three and four inches from the margin of the 
anus, and may be easily perforated without injury to any important parts. This 
portion of the bladder was consequently selected in the old days for the perform- 
ance of the now obsolete operation of tapping the bladder. 
Surgical Anatomy. Median Lithotomy.-As the incision is in the raphe, the hemor- 
rhage is trivial, and there is but slight risk of injuring the pelvic fascia. But the operation gives 
little room for manipulation and is inadmissible in children, because in them dilatation of the 
wound may tear the bladder loose from the urethra. A risk of median lithotomy is division of 
the artery of the bulb. 
In median lithotomy a grooved staff is introduced, the groove being median. The knife is 
introduced in the mid-line, just in front of the anal margin, and hits the staff near the apex 
of the prostate; the entire length of the membranous urethra is cut as the instrument is with- 
drawn. 
Parts Divided.-Skin, superficial fascia, sphincter ani muscle, central tendon of the 
perinaeum, inferior leaf of the triangular ligament, membranous urethra, and the Compressor 
urethrae muscle. 
Lateral Lithotomy.- The operation is performed on the left side of the perinaeum, as this 
is most convenient for the right hand of the operator. A grooved staff having been introduced 
into the bladder, the first incision is commenced midway between the anus and the back of 
the scrotum (i. e., in an ordinary adult perinaeum about an inch and a half in front of the anus) 
a little on the left side of the raph^, and is carried obliquely backward and outward to midw ay 
between the anus and tuberosity of the left ischium. The incision divides the integument and 
superficial fascia, the inferior hemorrhoidal vessels and nerves, and the superficial and trans- 
verse perineal vessels. If the forefinger of the left hand is thrust upward and forward into 
the wound, pressing at the same time the rectum inward and backw ard, the staff may be felt in 
the membranous portion of the urethra. The finger is fixed upon the staff, and the structures 
covering the staff are divided with the point of the knife, which must be directed along the groove 
toward the bladder, the edge of the knife being turned outward and backward, dividing in its 
course the membranous portion of the urethra and part of the left lobe of the prostate gland 
to the extent of about an inch. The knife is then withdrawn, and the forefinger of the left hand 
passed along the staff into the bladder. The position of the stone having been ascertained, the 
staff is to be withdrawn, and the forceps is introduced over the finger into the bladder. If the 
stone is very large, the opposite side of the prostate may need to be notched before the forceps 
is introduced; the finger is now withdrawn, and the blades of the forceps opened and made to 
grasp the stone, which must be extracted by slow and cautious undulating movements. 
Parts Divided in the Operation.-The various structures divided in this operation are as 
follows: the integument, superficial fascia, inferior hemorrhoidal vessels and nerves, and prob- 1542 
SURGICAL ANATOMY OF THE PERINEUM 
ably the superficial perineal vessels and nerves, the posterior fibres of the Accelerator urinae 
muscle, the Transversus perinaei muscle and artery, the triangular ligament, the anterior fibres of 
the Levator ani muscle, part of the Compressor urethrae muscle, the membranous and pros- 
tatic portions of the urethra, and part of the prostate gland. 
Parts to be Avoided in the Operation.-In making the necessary incisions in the perinaeum for 
the extraction of a calculus the following parts should be avoided: The primary incision should 
not be made too near the middle line, for fear of wounding the bulb of the corpus spongiosum 
or the rectum; nor too far externally, otherwise the internal pudic artery may be implicated as it 
ascends along the inner border of the pubic arch. If the incisions are carried too far forward, 
the artery of the bulb may be divided; if carried too far backward, the entire breadth of the pros- 
tate and neck of the bladder may be cut through, which allows the urine to become infiltrated 
behind the pelvic fascia into the loose areolar tissue between the bladder and rectum, instead 
of escaping externally; diffuse inflammation is consequently set up, and peritonitis, from the 
close proximity of the recto-vesical peritoneal fold, is the result. If, on the contrary, only the 
anterior part of the prostate is divided, the urine makes its way externally, and there is less 
danger of infiltration taking place. 
During the operation it is of great importance that the finger should be passed into the bladder 
before the staff is removed; if this is neglected, and if the incision made in the prostate and neck 
of the bladder is too small, great difficulty may be experienced in introducing the finger afterward; 
and in the child, where the connections of the bladder to the surrounding parts are very loose, 
the force made in the attempt is sufficient to displace the bladder upward into the abdomen, 
out of the reach of the operator. Such a proceeding has not unfrequently occurred, producing 
the most embarrassing results and total failure of the operation. 
It is necessary to bear in mind that the arteries in the perinseum occasionally take an abnormal 
course. Thus the artery of the bulb, when it arises, as sometimes happens, from the pudic 
opposite the tuber ischii, is liable in its passage forward to the bulb to be wounded in the 
operation of lithotomy. The accessory pudic may be divided near the posterior border of the 
prostate gland, if this gland is completely cut across; and if the prostatic veins are of large size, 
and give rise, when divided, to troublesome hemorrhage. In men advanced in years the pros- 
tatic veins are very apt to be enlarged. 
Extravasation of Urine.-Extravasation most commonly occurs from urethral rupture, 
between Colles's fascia and the triangular ligament of the urethra (extravasation in front of 
the triangular ligament). The adherence of these two fascial layers posteriorly prevents the 
urine from passing backward. The urine cannot find a way laterally, because both layers on 
each side are attached to the rami of the pubes and ischium. It cannot reach the pelvis, because 
the triangular ligament bars the way. It can only go forward if the two fascial layers remain 
intact, and consequently the urine passes into the areolar tissue of the scrotum beneath the 
superficial fascia of the penis and of the anterior abdominal wall. 
Pus and blood would pursue the same course in this space. Effusions in this space causes 
much pain, because the space contains the three long scrotal nerves. 
In rupture of the urethra between the two layers of the triangular ligament, the urine remains 
in this situation as long as fascia remains intact. If suppuration occurs, destruction of fascia 
liberates the urine. 
In rupture behind the superior layer of the triangular ligament (extravasation back of the 
triangular ligament), the urine passes into the ischio-rectal fossa and upward and backward 
into the pelvis. 
THE FEMALE PERINEUM. 
The female perinaeum presents certain differences from that of the male, in 
consequence of the whole of the structures which constitute it being perforated 
in the middle line by the vulvo-vaginal passage. 
The Superficial Fascia, as in the male, consists of two layers, of which the 
superficial one is continuous with the superficial fascia over the rest of the body, 
and the deep layer, corresponding to the fascia of Colles in the male, is, like it, 
attached to the ischio-pubic rami, and in front is continued forward through 
the labia majora to the inguinal region. Tt is of less extent than in the male, 
in consequence of being perforated by the aperture of the vulva. 
On removing this fascia the muscles of the female perinaeum, which have 
already been described (p. 461), are exposed (Figs. 311 and 1130). The Sphincter 
vaginae, corresponding to the Accelerator urinae in the male, consists of an atten- THE FEMALE PERINEUM 
1543 
uated plane of fibres, forming an orbicular muscle around the orifice of the 
vagina, instead of being united in a median raphe, as in the male. The Erector 
clitoridis is proportionately reduced in size, but differs in no other respect from 
the erector penis, and the Transversus perinaei is similar to the muscle of the 
same name in the male. 
The triangular ligament (Fig. 1130) is not strongly marked as in the male. 
It transmits the urethra and the tube of the vagina. 
The Compressor Urethrae corresponds with the Compressor urethrae in the male. 
It arises from the ischio-pubic ramus, and, passing inward, its anterior fibres blend 
with the muscle of the opposite side, in front of the urethra; its middle fibres, the 
most numerous, are inserted into the side of the vagina, and the posterior fibres 
join the central point of the perinseum. 
Suspensory ligament 
of clitoris 
Glans clitoris 
Erector 
clitoridie 
muscle 
Urethral _ 
orifice' 
Vestibule. 
Sphincter 
vaginae 
muscle 
Greater gland 
of vestibule, 
or gland of 
Bartholini 
Deep perineal 
muscle, with 
its under 
layer of fascia 
[ (the triangular 
L ligament) 
Superficial 
transverse, 
perineal 
muscle 
External 
obtwabor 
muscle 
Sacro- 
■ sciatic 
ligament 
Levator ani 
muscle 
Gluteus maximus 
muscle 
Os coccyx 
External sphincter 
ani muscle 
Fig. 1130.-The female perinseum after removal of the skin and superficial fascia. (Bardeleben.) 
The distribution of the internal pudic artery is the same as in the male (p.1540), 
and the pudic nerve has also a similar arrangement, the dorsal nerve being, 
however, very small and supplying the clitoris. 
The corpus spongiosum is divided into two lateral halves, which are represented 
by the bulbi vestibuli and partes intermediates. 
The Perineal Body fills up the interval between the lower part of the vagina 
and the rectum. Its base is covered by the skin lying between the anus and 1544 
SURGICAL ANATOMY OF THE PER LN Ml UM 
vagina on what is called the perinaeum. Its anterior surface lies behind the pos- 
terior vaginal wall, and its posterior surface lies in front of the anterior rectal 
wall and the anus. It measures about an inch and a quarter from before back- 
ward, and laterally extends from one tuberosity of the ischium to the other. In it 
are situated the muscles belonging to the external organs of generation. Through 
its centre runs the transverse perineal septum, which is of great strength in women, 
and forms on either side, behind the posterior commissure, a hard, ill-defined 
body, consisting of connective tissue, with much yellow elastic tissue and inter- 
lacing bundles of involuntary muscular fibres, in which the voluntary muscles of 
the perinaeum are inserted. 
The Pelvic Fascia (fascia pelvis) (Figs. 304 and 1131).-The pelvic fascia 
strengthens the floor of the pelvis, fastens pelvic structures together, and supports 
the nerves, blood-vessels, and lymphatics. It is connected above with the trans- 
Crest 
of ilium. 
Iliac Fascia. 
Anterior 
crural nerve. 
Femoral vessels. 
Brim of 
pelvis. 
Pelvic 
'fascia. 
Obturator fascia. 
Internal pudic vessels, 
and nerve. 
Tuberosity of 
ischium. 
Fig. 1131.-A transverse section of the pelvis, showing the pelvic fascia from behind. 
versalis fascia and the iliac fascia. It is at first a thin membrane and covers the 
inner surface of the pelvis, being attached to the brim for a short distance at the 
side of the cavity and to the inner surface of the bone around the attachment of 
the Obturator internus. At the posterior portion of this muscle it is continued 
backward as a very thin membrane in front of the Pyriformis muscle to the front 
of the sacrum. In front, as it descends, it gives off the parietal layer of the pelvic 
fascia, which continues as the obturator fascia. It then becomes thicker and covers 
the inner and upper surface of the Diaphragm of the pelvis as far «as the white 
line (arcus tendineus fasciae pelvis'). The portion covering the superior and upper 
surface of the pelvic Diaphragm is the inner sheath of the Levator ani muscle and 
is called the visceral layer of the pelvic fascia or the recto-vesical fascia (fascia 
diaphragmatic pelvis superior). The white line is a rough band of fascial thick- 
ening, seen in the pelvic fascia of each side. It indicates the line of separation 
between the pelvic cavity anti the ischio-rectal fossa. It passes from the lower THE FEMALE PERINEUM 
1545 
portion of the symphysis pubis outward and backward to the spine of the ischium. 
It makes the attachment of the Levator ani muscle to the pelvic fascia. At the white 
line the chief mass of the pelvic fascia passes upon the pelvic viscera and is known 
as the fascia endo-pelvica. It covers portions of the vagina, rectum, and urinary 
bladder, becomes thinner and thinner, and is gradually lost. Other bands of fascia 
begin at the white line, descend on the inner surface of the recto-vesical fascia, and 
in the male pass to the tip of the prostate and become the prostatic fascia. Between 
the anterior ends of the two white lines the level of the fascia is lower, and it forms 
a fossa, bounded on the sides in the male by the pubo-prostatic ligaments (liga- 
menta puboprostatica lateralia), and in the female by the pubo-vesical ligaments 
(ligamenta pubovesicalia lateralia). These ligaments are called the lateral true 
ligaments of the bladder. In the base of this fossa in the male runs the anterior true 
ligament of the bladder or the pubo-prostatic ligament (ligamentum puboprostaticum 
Bladder. 
Glans. 
Fig. 1132.-Side view of the pelvic viscera of the male subject, showing the pelvic and perineal fasciae. 
medium'), and in the female the anterior true vesical ligament (ligamentum pubo- 
vesicale medium). These ligaments arise from the lowest portion of the symphysis 
and pass to the urinary bladder and prostate in the male, and urinary bladder and 
urethra in the female (Spalteholz). The outer surface of the pelvic Diaphragm is 
covered by the anal fascia or the ischio-rectal fascia fascia diaphragmatis pelvis 
inferior). It is the lower or outer sheath of the Levator ani muscle, and is derived 
from the obturator fascia. The space between the obturator fascia and the anal 
fascia is pyramidal and is called the ischio-rectal fossa (fossa ischiorectalis). 
The pelvic fascia does not completely invest the bladder, although the neck and 
lateral walls lie upon the Levator ani muscles, and the lateral true ligaments and 
the anterior ligament ascend upon the sides and front of the bladder and are lost 
upon the fibrous coat of that viscus. The sides and anterior wall have a fascial 
investment. The sheath of the prostate has already been discussed (p. 1449). It is 1546 
SURGICAL ANATOMY OF THE PERINEUM 
continuous with the recto-vesical fascia and the anterior true ligament of the 
bladder. 
The pelvic fascia is composed, according to Hughes, of: 1. The fibrous cap- 
sules of the pelvic viscera. 2. The sheaths of the Levator ani and Coccygei 
muscles (recto-vesical and anal fasciae). 3. The sheath of the Obturator internus 
(obturator fascia). 4. Sheath of the Compressor urethrae muscle (the triangular 
ligament). 5. The sheath of the pelvic aspect of the Pyriformis muscle. The 
sacral plexus is outside this sheath, the internal iliac vessels inside of it.1 As pre- 
viously stated, the pelvic fascia gives off the obturator fascia and the recto-vesical 
fascia. 
The Obturator Fascia (fascia obturatoria) descends and covers the Obturator 
internus muscle. It is a direct continuation of the parietal pelvic fascia below 
the white line above mentioned, and is attached to the pelvic arch, the ischial 
tuberosities, and to the margin of the great sacro-sciatic ligaments. This fascia 
forms a canal for the pudic vessels and nerve in their passage forward to the 
perinreum, and gives off a thin membrane which covers the perineal aspect of the 
Levator ani muscle, and is called the anal or ischio-rectal fascia. It forms the inner 
boundary of the ischio-rectal fossa. From its attachment to the rami of the os 
pubis and ischium a process is given off which is continuous with a similar process 
from the opposite side, so as to close the front part of the outlet of the pelvis, form- 
ing the deep layer of the triangular ligament. 
The Recto-vesical Fascia or the Visceral Layer of the Pelvic Fascia 
(fascia endopelvica) descends into the pelvis upon the upper surface of the Levator 
ani muscle, and invests the prostate, bladder, and rectum. From the inner sur- 
face of the symphysis pubis a short rounded band is continued, on each side of 
the middle line, to the upper surface of the prostate and neck of the bladder, form- 
ing the pubo-prostatic or anterior true ligaments of the bladder. At the side this 
fascia is connected to the side of the prostate, enclosing this gland and the vesico- 
prostatic plexus of veins, and is continued on to the side of the bladder, forming 
the lateral true ligaments of the organ. Another prolongation invests the seminal 
vesicle, and passes across between the bladder and rectum, being continuous 
with the same fascia of the opposite side. Another thin prolongation is reflected 
around the surface of the lower end of the rectum. The Levator ani muscle arises 
from the point of division of the pelvic fascia, the visceral layer of the fascia 
descending upon and being intimately adherent to the upper surface of the muscle, 
while the under surface of the muscle is covered by a thin layer derived from the 
obturator fascia, called the ischio-rectal or anal fascia. In the female the vagina 
perforates the recto-vesical fascia and receives a prolongation from it. 
1 A Manual of Practical Anatomy. By Prof. Alfred W. Hughes; edited and completed by Dr. Arthur Keith. CHRONOLOGICAL TABLE 
OF 
THE DEVELOPMENT OF THE FCETUS 
(From Beaunis and Bouchard.) 
First Week.-During this period the ovum is in the Fallopian tube. Having been fertilized in 
the upper part of the tube, it slowly passes down, undergoing segmentation, and reaches 
the uterus probably about the end of the first week. During this time it does not undergo 
much increase in size. 
Second Week.-The ovum rapidly increases in size and becomes imbedded in the decidua, so 
that it is completely enclosed in the decidua reflexa by the end of this period. An ovum 
believed to be of the thirteenth day after conception is described by Reichert. There was 
no appearance of any embryonic structure. The equatorial margins of the ovum were beset 
with villi, but the surface in contact with the uterine wall and the one opposite to it were 
bare. In another ovum, described by His, believed to be of about the fourteenth day, 
there was a distinct indication of an embryo. There was a medullary groove bounded by 
folds. In front of this a slightly prominent ridge, the rudimentary heart. The amnion 
was formed and the embryo was attached by a stalk, the allantois, to the inner surface of 
the chorion. It may be said, therefore, that these parts, the amnion and the allantois, and 
the first rudiments of the embryo, the medullary groove, and the heart, are formed at the 
end of the second week. 
Third Week.-By the end of the third week the flexures of the embryo have taken place, so 
that it is strongly curved. The protovertebral disks, which begin to be formed early in the 
third week, present their full complement. In the nervous system the primary divisions 
of the brain are visible, and the primitive ocular and auditory vesicles are already formed. 
The primary circulation is established. The alimentary canal presents a straight tube com- 
municating with the yolk-sac. The branchial arches are formed. The limbs have appeared 
as short buds. The Wolffian bodies are visible. 
Fourth Week.-The umbilical vesicle has attained its full development. The caudal extremity 
projects. The upper and the lower limbs and the cloacal aperture appear. The heart sep- 
arates into a right and left heart. The special ganglia and anterior roots of the spinal 
nerves, the olfactory fossae, the lungs and the pancreas can be made out. 
Fifth Week.-The allantois is vascular in its whole extent. The first traces of the hands and 
feet can be seen. The primitive aorta divides into aorta and pulmonary artery. The duct 
of Muller and genital gland are visible. The ossification of the clavicle and the lower jaw 
commences. The cartilage of Meckel occupies the first post-oral arch. 
Sixth Week.-The activity of the umbilical vesicle ceases. The pharyngeal clefts disappear. 
The vertebral column, primitive cranium, and ribs assume the cartilaginous condition. The 
posterior roots of the nerves, the membranes of the nervous centres, the bladder, kidney, 
tongue, larynx, thyroid body, the germs of teeth, and the genital tubercle and folds 
are apparent. 
Seventh Week.-The muscles begin to be perceptible. The points of ossification of the ribs, 
scapula, shaft of humerus, femur, tibia, palate, and upper jaw appear. 
Eighth Week.- The distinction of arm and forearm, and of thigh and leg, is apparent, as well as 
the interdigital clefts. The capsule of the lens and pupillary membrane, the interventricu- 
lar and commencement of the interauricular septum, the salivary glands, the spleen, and 
suprarenal capsules are distinguishable. The larynx begins to become cartilaginous. All 
the vertebral bodies are cartilaginous. The points of ossification for the ulna, radius, fibula, 
and ilium make their appearance. The two halves of the hard palate unite. The 
sympathetic nerves are now for the first time to be discerned. 
1 [Eternod {Anat. Anzeiger, Band xv., 1898) described an ovum which h0 reconstructed. It 
had a precise history, from which he concluded that it must have belonged to the end of the second 
or the beginning of the third week. Including the villi it measured 10 X 8.2 X 6 mm. It was 
flattened on its embryonal side, and the embryo measured 1.3 mm. The amnion was^ompletely 
formed and the allantois existed as a long canal. The vitelline circulation was established and the 
villi of the chorion were beginning to be vascularized. The blastopore still opened into the amniotic 
cavity, with the primitive groove behind it and the rudimentary groove in front. The notochord 
was closing in and all three layers of the blastoderm were distinct, except around the blastopore, where 
they formed an undivided mass.-Ed. of 15th English edition.] 
1547 1548 
THE FCETUS. 
Ninth Week.-The corpus striatum and the pericardium are first apparent. The ovary and 
testicle can be distinguished from each other. The genital furrow appears. The osseous 
nuclei of the bodies and arches of the vertebrae, of the frontal, vomer, and malar bones of the 
shafts of the metacarpal and metatarsal bones, and of the phalanges appear. The union of 
the hard palate is completed. The gall-bladder is seen. 
Third Month.-The formation of the foetal placenta advances rapidly. The projection of the 
caudal extremity disappears. It is possible to distinguish the male and female organs from 
each other. The cloacal aperture in divided into two parts. The cartilaginous arches on the 
dorsal region of the spine close. The points of ossification for the occipital, sphenoid, 
lachrymal, nasal, squamous portion of temporal and ischium appear, as well as the orbital 
centre of the superior maxillary. The pons Varolii and fissure of Sylvius can be made out. 
The eyelids, the hair, and the nails begin to form. The mammary gland, the epiglottis, 
and prostate are beginning to develop. The union of the testicle with the canals of the 
Wolffian body takes place. 
Fourth Month.-The closure of the cartilaginous arches of the spine is complete. Osseous 
points for the first sacral vertebra and os pubis appear. The ossification of the malleus and 
incus takes place. The corpus callosum, the membrana lamina spiralis, the cartilage of 
the Eustachian tube, and the tympanic ring are seen. Fat is first developed in the sub- 
cutaneous cellular tissue. The tonsils are seen, and the closure of the genital furrow and 
the formation of the scrotum and prepuce take place. 
Fifth Month.-The two layers of the decidua begin to coalesce. Osseous nuclei of the axis and 
odontoid process, of the lateral points of the first sacral vertebra, of the median points of 
the second, and of the lateral masses of the ethmoid make their appearance. Ossification 
of the stapes and the petrous bone and ossification of the germs of the teeth take place. 
The germs of the permanent teeth and the organ of Corti appear. The eruption of hair on 
the head commences. The sudoriferous glands. Brunner's glands, the follicles of the tonsil 
and base of the tongue, and the lymphatic glands appear at this period. The differentiation 
between the uterus and vagina becomes apparent. 
Sixth Month.-The points of ossification for the anterior root of the transverse process of the 
seventh cervical vertebra, the lateral points of the second sacral vertebra, the median points 
of the third, the manubrium sterni and the os calcis appear. The sacro-vertebral angle 
forms. The cerebral hemispheres cover the cerebellum. The papillae of the skin, the 
sebaceous glands, and Peyer's patches make their appearance. The free border of the 
nail projects from the corium of the dermis. The walls of the uterus thicken. 
Seventh Month.-The additional points of the first sacral vertebra, the lateral points of the 
third, the median point of the fourth, the first osseous point of the body of the sternum, 
and the osseous point for the astragalus appear. Meckel's cartilage disappears. The 
cerebral convolutions, the island of Reil, and the tubercula quadrigemina are apparent. The 
pupillary membrane atrophies. The testicle passes into the vaginal process of the 
peritoneum. 
Eighth Month.-Additional points for the second sacral vertebra, lateral points for the fourth 
and median points for the fifth sacral vertebrae, can be seen. 
Ninth Month.-Additional points for the third sacral vertebra, lateral points for the fifth, 
osseous points for the middle turbinated bone, for the body and great cornu of the hyoid, 
for the second and third pieces of the body of the sternum, and for the lower end of the 
femur appear. Ossification of the bony lamina spiralis and axis of the cochlea takes place. 
The eyelids open, and the testicles are in the scrotum. INDEX. 
A 
Abdomen, 1231 
boundaries of, 1231 
fascia of, deep, 433 
superficial, 433, 1511 
triangular, 1515 
lymphatics of, 797, 800 
muscles of, 432 
actions of, 445, 449 
deep, 449 
dissection of, 432 
superficial, 432 
surface form of, 448 
nerves of, cutaneous, 996 
regions of, 1233 
veins of, 755 
viscera, 1234 
walls of, apertures in, 1233 
of, lymphatic vessels of, 
deep, 801 
superficial, 801 
Abdominal aorta, 668 
branches of, 671 
relations of, 669 
surface marking of, 670 
surgical anatomy of, 670 
aortic plexus, 1080, 1085 
intercostal nerves, 996 
muscles, 432 
portion of oesophagus, 1226 
ring, external, 436, 1514 
internal, 446, 1518 
pillars of, 1514 
sacs, 1236 
surface of bladder, 1433 
viscera, position of, 1234 
Abdomino-aortic glands, 799 
-thoracic arch, 165 
Abducent nerve, 1043 
branches of, 1043 
relations of, 1043 
surgical anatomy of, 1044 
Abductor hallucis muscle, 544 
relations of, 544 
indicis muscle, 499 
minimi digiti muscle, foot, 545 
relations of, 545 
hand, 498 
relations of, 498 
pollicis muscle, 495 
relations of, 496 
Aberrant ducts of epididymis, 
1472 
Absorbent glands, 774 
Absorbents, 772 
Accelerator urin® muscle, 457 
Accessorius ad ilio-costalem mus- 
cle, 419 
pedis, 546 
Accessory anterior crural nerve 
of Winslow, 1004 
auditory nuclei, 950 
chains to deep cervical glands, 
787 
cuneate nucleus, 948 
Accessory descending palatine 
canals, 116 
gland of Rosenmuller, 1141 
ligament of atlas, 276 
nucleus of eighth nerve, 1051 
obturator nerve, 1004 
olivary nuclei, 951 
parotid gland, 1215 
posterior palatine canals, 116, 
135 
processes, 57 
quadrate cartilage, 1097 
suprarenal glands, 1430 
thyroid glands, 1403 
veins, 731 
Acervulus cerebri, 906 
Acetabulum, 213 
fossa of, 213 
ligaments of, transverse, 330 
Acoustic canal, external, 1148 
tubercle, lateral, 950 
Acromial angle, 176 
region, fascia of, 470 
muscles of, 470 
actions of, 471 
surgical anatomy of, 471 
thoracic artery, 651 
Acromio-clavicular articulation, 
299 
surface form of, 311 
surgical anatomy of, 301 
ligament, inferior, 299 
superior, 299 
Acromion process, 174 
Additus glottidis inferior, 1371 
Adductor brevis muscle, 520 
relations of, 520 
canal, 698 
longus muscle, 519 
relations of, 519 
magnus muscle, 520 
relations of, 521 
minimus muscle, 520 
obliquus hallucis muscle, 546 
pollicis muscle, 497 
relations of, 497 
transversus hallucis muscle, 
548 
relations of, 548 
pollicis muscle, 497 
relations of, 497 
tubercle, 225 
Adipose tissue, pads of, 263 
Aditus ad antrum, 87, 1150 
Adminiculum line® alb®, 437 
Afferent nerve tract, 961 
vessels of kidneys, 1423 
Agminated glands, 1296 
Air cells, 1396 
sinus, 82 
Ala cinerea, 945 
lobuli centralis, 928 
nasi, 1096 
artery of, 607 
Al® of cerebellum, 928 
of ethmoid, 99 
Al® of sacrum, 64 
of vomer, 121, 143 
Alar cartilage, greater, 1097 
lesser, 1097 
ligaments, 278 
thoracic artery, 651 
Alcock's canal, 1011, 1536 
Alimentary canal, 1193 
development of, 1236 
Alveolar artery, 615 
inferior, 614 
superior, 615 
ducts, 1378 
hare-lip, 111 
processes, 140 
of superior maxillary, 109 
Alveoli, mucous, 1218 
pulmonary, 1378 
serous, 1218 
of stomach, 1278 
of teeth, development of, 1207 
Alveus, 896 
Amacrine cells of retina, 1125 
Ameoblasts, 1206 
Amphiarthrosis, 264 
Ampullae of Fallopian tube, 1497 
membranaceae, 1170 
ossea, 1165 
tubuli lactiferi, 1507 
of Vater, 1345 
Amygdala, 1213 
of cerebellum, 931 
Amygdaloid nucleus, 891 
Anal canal, 1315 
areolar coat of, 1318 
mucous membrane of, 1318 
muscular coat of, 1317 
relations of, 1316 
serous coat of, 1316 
structure of, 1316 
submucous coat of, 1318 
fascia, 454, 1546 
pockets, 1319 
valves, 1319 
Anastomosis of arteries, 583 
circumpatellar, 711 
Anastomotic vein of Trolard, 735 
Anastomotica magna of brachial, 
656 
of femoral, 707 
Anatomical neck of humerus, 177 
of scapula, 175 
Anconeus muscle, 487 
relations of, 487 
Andersch, ganglion of, 1056 
Angle, acromial, 176 
cephalo-auricular, 1144 
of jaw, 124 
lateral, inferior, 63 
of Ludwig, 165 
nasal, 105 
of os pubis, 212 
of ribs,, 161 
Rolandic, 867 
sacro-vertebral, 61 
of sternum, 157 
1549 1550 
INDEX 
Angle, subscapular, 172 
Angular artery, 607 
convolution, 876 
gyrus, 876 
process, external, 80, 140 
internal, 80, 140 
vein, 726 
Ankle bone, 244 
bursae of, 543 
-joint, articulations of, 347 
ligaments of, 347 
surface form of, 351 
surgical anatomy of, 351 
Anneetant gyrus, deep, 867 
first, 876 
fourth, 877 
second, 876 
third, 877 
Annular ligament of ankle, an- 
terior, 541 
external, 542 
internal, 542 
of radius and ulnar, 314 
of stapes, 1161 
of wrist, anterior, 491 
posterior, 493 
plexus, 1111 
Annulus ciliaris, 1115 
ovalis, 567 
Ano-coccygeal body of Syming- 
ton, 1316 
Ansa hypoglossi, 1066 
lenticularis, 915 
peduncularis, 892 
of Vieussens, 1076 
Ante-cubital glands, 789 
Anterior angle of ribs, 161 
annular ligament of ankle, 541 
of wrist, 491 
atlanto-axial ligament, 274 
atlo-axoid ligament, 274 
auricular artery, 611 
nerves, 1038 
bicipital ridge, 179 
branches of superior cervical 
ganglion, 1076 
cardiac plexus, 1081 
carpal arch, 659 
of ulnar, 663 
cerebellar notch, 926 
cerebral artery, 626 
chamber of eye, 1129 
chondro-sternal ligament, 288 
-xiphoid ligament, 288 
choroid artery, 628 
ciliary arteries, 625 
clinoid process, 131 
commissure of cerebrum, 896 
of cord, 839 
common ligament, 269 
communicating artery of ul- 
nar, 662 
condyloid foramen, 73, 133, 
136 
fossa, 136 
cornu of lateral ventricle, 889 
coronary plexus, 1081 
costo-vertebral ligament, 284 
-xiphoid ligament, 288 
crescentic lobe, 928 
crucial ligament, 337 
crural nerve, 1004 
accessory, of Winslow, 
1004 * 
deep cervical vein, 733 
divisions of cervical nerves, 
971 
of coccygeal nerves, 1009 
of dorsal nerves, 993 
of lumbar nerves, 998 
of thoracic nerves, 993 
Anterior dental canal, 107 
ethmoidal canal, 82, 100 
cells, 101 
foramen, 82, 130, 141 
sinuses, 101 
extremity of ribs, 161 
facial vein, 726 
femoral region, muscles of, 512 
fontanelle, 78, 103 
fossa of skull, 130 
gluteal line, 207 
humeral region, muscles of, 
474 
inferior cerebellar artery, 640 
spinous process of ilium, 210 
intercostal arteries, 644 
veins, 752 
internal frontal artery, 627 
interosseous artery of ulnar, 
662 
nerve, 987 
intersternal ligament, 290 
intertrochanteric line, 223 
jugular vein, 728 
ligament of Helmholtz, 1160 
of malleus, 1160 
of wrist, 318 
longitudinal ligament, 269 
spinal veins, 754 
mediastinal glands, 811 
mediastinum, 1389 
medullary velum, 943 
meningeal artery, 622 
nares, 142, 1098 
nasal spine, 111, 139, 143 
occipito-atlantal ligament, 276 
olfactory lobule, 880 
orbital convolution, 874 
palatine canal, 143 
fossa, 110, 133 
nerve, 1035 
perforated space, 881 
perforating arteries, 644 
peroneal artery, 718 
pillars of fornix, 895 
of soft palate, 1212 
pubic ligament, 296 
pulmonary nerves, 1061 
plexus, 1059, 1061, 1082 
radial carpal artery, 659 
radio-ulnar ligament, 315 
region, muscles of, 479 
recurrent tibial artery, 713 
region of skull, 139 
root of spinal nerves, 965 
sacral foramina, 62 
sacro-coccygeal ligament, 294 
-iliac ligament, 292 
-sciatic ligament, 293 
scapular region, muscles of, 
471 
spinal artery, 638 
sterno-clavicular ligament, 298 
-costal ligament, 288 
subarachnoid space, 853 
superior dental nerve, 1033 
ligament, 285 
spinous process of ilium, 210 
surface of liver, 1327 
of stomach, 1269 
temporal artery, 611, 640 
diploic vein, 734 
thoracic nerve, 984 
tibial artery, 711 
gland, 795 
nerve, 1016 
veins, 758 
tibio-fibular region, muscles of, 
531 
-tarsal ligament, 347 
triangle of neck, 616 
Anterior tubercle of cervical ver- 
tebra, 50 
of optic thalamus, 904 
tympano-malleolar ligament. 
' 1156 
ulnar recurrent artery, 662 
vein, 745 
vertebral region, muscles of, 
406 
vein, 733 
wall of tympanum, 1153 
Antero-lateral fissure, 838 
fontanelle, 103 
ganglionic arteries, 628 
tract of cord, 842 
-median fissure, 837 
ganglionic arteries, 627 
-posterior Ldiameter of pelvis, 
217 
Antihelix, 1144 
fossa of, 1144 
Antitragicus muscle, 1147 
Antitragus, 1145 
Antrum of Highmore, 108 
mastoid, 87 
opening of, 1153 
of pylorus, 1271 
tympanic, 87 
Anus, 1315 
arteries of, 1320 
lymphatics of, 809, 1321 
nerves of, 1322 
veins of, 1321 
Aorta, 587 
abdominal, 668 
arch of, 591 
branches of, 593 
peculiarities of, 591, 593 
relations of, 591 
surgical anatomy of, 592 
ascending, 588 
descending, 665 
sinus of, great, 589 
thoracic, 665 
transverse, 590 
Aortic isthmus, 591 
opening of diaphragm, 429 
of heart, 566 
semilunar valves, 572 
sinus of Valsalva, 573 
spindle, 591 
vestibule of Sibson, 572 
Apertura scake vestibuli cochleae, 
1165 
tympanica canaliculi chordae, 
1153 
Aperture of nose, cartilage of, 
1097 
Apical coil of cochlea, 1167 
glands, 1091 
Aponeurosis of external oblique, 
434, 1513 
of internal oblique, 439 
palatine, 404 
pharyngeal, 402, 1223 
Sibs»on's, 1385 
of soft palate, 1212 
supra-hyoid, 394 
vertebral, 411, 416 
Apophysis, 34 
Appendages of eye, 1137 
of skin, 1185 
of uterus, 1497 
Appendices epiploicse, 1260 
Appendicular artery, 676 
vein, 768 
Appendiculo-ovarian ligament of 
Clado, 1304 
Appendix of auricle, left, 568 
right, 565 
ensiform, 158 INDEX 
1551 
Annendix, vermiform, 1303 
xiphoid, 158 
Aqueduct of Sylvius, 912 
Aquseductus cochleae, 89, 136, 
1167 
Fallopii, 89 
eminence of, 1152 
vestibuli, 89, 133, 1165 
Aqueous chamber, 1128 
humor, 1128 
Arachnoid of brain, 851 
structure of, 853 
of cord, 834 
structure of, 835 
villi, 854 
Arangi, body of, 571 
Arantius, ventricle of, 944 
Arbor vitae of cerebellum, 931 
of uterus, 1492 
Arch of aorta, 591 
branches of, 593 
peculiarities of, 591, 593 
relations of, 591 
surgical anatomy of, 592 
of atlas, 51 
axillary, 413, 464, 646 
carpal, anterior, 659 
posterior, 659 
crural, deep, 448, 1531 
superficial, 436, 1529 
palmar, deep, 658 
superficial, 664 
plantar, 720 
pubic, 217 
supraorbital, 80 
tarsal, inferior, 623 
superior, 623 
of vertebra, 48 
zygomatic, 138 
Arciform fibres of medulla, 942 
Arcuate fibres of medulla, 942 
ligaments, external, 427, 449 
internal, 427 
middle, 427 
Arcus senilis, 1110 
Area of Broca, 881 
cribrosa media, 89 
superior, 89 
vestibularis, inferior, 1176 
superior, 1176 
Areolae of bone, primary, 44 
secondary, 45 
of mamma, 1504 
Areolar coat of anal canal, 1318 
of intestine, large, 1318 
small, 1290 
of liver, 1337 
of oesophagus, 1229 
of rectum, 1318 
of stomach, 1274 
tissue, subcutaneous, 1180 
subserous, 1245 
Arm, arteries of, 637 
bones of, 177 
fasciae of, 474 
deep, 470 
superficial, 470 
lymphatics of, 789 
muscles of, 470, 474 
dissection of, 470, 474 
surgical anatomy of, 478 
nerves of, 977 
veins of, 744 
Arnold's ganglion, 1039 
branches of, 1039 
nerve, 1060 
canal for, 90 
ponticulus of, 939 
Arteria centralis retinae, 626 
magna, 587 
Arteriae hallucis, 716 
Arteriae princeps cervicis, 609 
receptaculi, 622 
uterina ovarica, 688 
Artery or arteries, 583 
alveolar, 615 
inferior, 614 
superior, 615 
anastomosis of, 583 
anastomotica magna of brach- 
ial, 656 
of femoral, 707 
angular, 607 
antero-lateral ganglionic, 628 
-median ganglionic, 627 
aorta, 587 
abdominal, 668 
arch of, 591 
ascending, 588 
descending, 665 
thoracic, 665 
appendicular, 676 
arteriae receptaculi, 622 
articular, of knee, 710, 711 
auditory, 639 
auricular, anterior, 611 
posterior, 609 
axillary, 647 
azygos, of knee, 711 
of vagina, 687 
basilar, 639 
brachial, 652 
of brain, cortical, 631 
bronchial, 666 
buccal, 615 
of bulb, 691 
bulbar, 639 
calcanean, external, 718 
internal, 719 
carotid, common, 595 
external, 600 
internal, 619 
carpal arch, anterior, 659 
posterior, 657 
radial, anterior, 659 
posterior, 659 
ulnar, anterior, 663 
posterior, 663 
centralis retinae, 626 
cerebellar, anterior inferior, 
640 
posterior inferior, 639 
superior, 640 
cerebral, anterior, 626 
of cerebral hemorrhage, 628 
middle, 627 
posterior, 640 
cervical, ascending, 641 
deep, 646 
superficial, 642 
transverse, 642 
choroid, anterior, 628 
posterior, 640 
ciliary, 625 
circle of Willis, 640 
circumflex, of arm, 651 
iliac, deep, 697 
superficial,704 
of thigh, 705 
cochlear, 1176 
coccygeal, 692 
cceliac, 671 
colic, left, 678 
middle, 676 
right, 675 
comes nervi ischiadici, 693 
mediana, 663 
phrenici, 644 
communicating, anterior cere- 
bral, 627 
to deep palmar arch, 664 
posterior cerebral, 628 
Artery or arteries, communicat- 
ing, of ulnar, anterior, 662 
coronary, 671 
of heart, 590 
of lip, inferior, 607 
superior, 607 
of corpus cavernosum, 691 
cremasteric, 696 
crico-thyroid, 602 
cystic, 674 
dental, anterior, 605 
inferior, 614 
posterior, 615 
digital, plantar, 659 
of ulnar, 664 
dorsalis hallucis, 716 
indicis, 659 
linguae, 603 
nasi, 625 
pedis, 714 
pollicis, 659 
scapulae, 651 
of dura mater of brain, 848 
epigastric, deep, 696 
internal, 696 
superficial, 704 
superior, 645 
ethmoidal, 623 
facial, 604 
transverse, 611 
femoral, 697 
common, 699 
deep, 704 
fibular, superior, 713 
frontal, 611 
from anterior cerebral, 628 
from middle cerebral, 628 
from ophthalmic, 625 
ganglionic, postero-lateral, 640 
postero-median, 640 
gastric, 671, 674 
gastro-duodenalis, 673 
-epiploica dextra, 673 
sinistra, 674 
gluteal, 694 
inferior, 693 
haemorrhoidal, inferior, 690 
middle, 687 
- superior, 678- 
of head, 595 
of heart, 577 
hepatic, 672 
histology of, 584 
hyoid branch of lingual, 603 
of superior thyroid, 602 
hypogastric, 683 
in foetus, 684 
ileo-colic, 675 
iliac, circumflex, deep, 697 
superficial, 704 
common, 681 
external, 694 
internal, 683 
ilio-lumbar, 693 
infra-hyoid branch of superior 
thyroid, 602 
infraorbital, 615 
innominate, 593 
inosculation of, 583 
intercostal, 667 
anterior, 644 
superior, 645 
interlobar, 1423 
interosseous, of foot, 715 
of hand, 660 
ulnar, 662 
anterior, 662 
posterior, 663 
labial, inferior, 607 
lachrymal, 623 
laryngeal, inferior, 641 1552 
INDEX 
Artery or arteries, laryngeal, 
superior, 602 
lateralis nasi, 607 
lenticulo-striate, 628 
lingual, 603 
deep, 604 
of lower extremity, 697 
lumbar, 680 
lymphatics of, 586 
malar from lachrymal, 623 
malleolar, 713, 719 
mammary, internal, 643 
mandibular, 614 
marginal, 590 
masseteric, 615 
mastoid, 609, 670 
maxillary, external, 604 
internal, 612 
mediastinal, 644 
posterior, 666 
meningeal, 609, 610 
anterior, 622 
middle, 613 
from occipital, 609 
from pharyngeal, 610 
posterior, 638 
small, 614 
from vertebral, 638 
mesenteric, inferior, 677 
superior, 675 
metatarsal, 715 
musculo-phrenic, 644 
mylo-hyoid, 614 
nasal, from ophthalmic, 625 
of septum, inferior, 607 
superior, 615 
naso-palatine, 616 
of neck, 595 
nerves of, 586 
nutrient, of femur, 707 
of fibula, 718 
of humerus, 656 
of tibia, 718 
obturator, 688 
occipital, 608 
oesophageal, 641, 666 
ophthalmic, 622 
orbital, 611 
internal, 627 
ovarian, 680 
palatine, ascending, 606 
descending, 615 
inferior, 606 
posterior, 615 
palmar arch, deep, 658 
superficial, 664 
palpebral, external, 623 
internal, 623 
pancreatic, 674 
pancreatico-duodenalis, infe- 
rior, 675 
superior, 674 
parietal, 611 
ascending, 628 
parieto-sphenoidal, 628 
-temporal, 628 
of penis, dorsal, 689, 1458 
perforating, anterior, 644 
of foot, 720 
of hand, 660 
of thigh, 706 
pericardia*, 644, 666 
of pericardium, 561 
perineal, superficial, 690 
transverse, 691 
peroneal, 717 
anterior, 718 
posterior, 718 
pharyngeal, ascending. 610 
phrenic, inferior, 680 
superior, 644 
Artery or arteries of pia mater 
of brain, 856 
plantar, digital, 720 
external, 720 
internal, 719 
popliteal, 707 
postero-median ganglionic, 628 
prevertebral, 610 
princeps cervicis, 610 
hallucis, 716 
pollicis, 660 
profunda of arm, inferior, 656 
superior, 655 
femoris, 704 
pterygo-palatine, 616 
pterygoid, 614 
pudic, accessory, 690 
external, deep, 704 
superficial, 704 
internal, in female, 692 
in male, 689 
pulmonary, 587 
pyloric, inferior, 673 
superior, 673 
radial, 657 
fadialis indicis, 660 
ranine, 604 
recurrent, palmar, 660 
radial, 659 
tibial, anterior, 713 
posterior, 713 
ulnar, anterior, 662 
posterior, 662 
renal, 678 
inferior, 1423 
of round ligament, 688 
sacral, lateral, 693 
middle, 681 
scapular, posterior, 642 
sciatic, 692 
sigmoid, 678 
spermatic, 679 
spheno-palatine, 616 
spinal, anterior, 638 
lateral, 638 
posterior, 639 
splenic, 674 
sternal, 644 
sterno-mastoid, 602, 609 
stylo-mastoid, 610 
subclavian, 631 
subcostal, 667 
sublingual, 604 
submaxillary, 606 
submental, 606 
subscapular, 651 
superficialis vol®, 659 
supra-acromial, 642 
-hyoid, 603 
supraorbital. 623 
suprarenal, 678 
suprascapular, 641 
suprasternal, 642 
sural, 710 
tarsal, 715 
temporal, 611 
anterior, 611, 640 
deep, 614 
middle, 611 
posterior, 611, 640 
thoracic, acromial, 651 
alar, 651 
long, 651 
superior, 650 
thyroid axis, 640 
inferior, 641 
superior, 601 
of thyroid gland, 602 
thyroidea ima, 594 
tibial, anterior, 711 
posterior, 716 
Artery or arteries, tibial, recur- 
rent, anterior, 713 
posterior, 713 
tonsillar, 606 
tracheal, 641 
transversalis colli, 642 
humeri, 641 
of trunk, 665 
tympanic, from ascending 
pharyngeal, 610 
from internal carotid, 622 
from internal maxillary, 613 
ulnar, 660 
recurrent, anterior, 662 
posterior, 662 
umbilical, in foetus, 579, 685 
of upper extremity, 631 
uterine, 687 
vaginal, 687 
of vas deferens, 686 
vasa brevia, 674 
intestini tenuis, 675 
vasorum of, 586 
vertebral, 637 
vesical, inferior, 686 
middle, 686 
superior, 686 
Vidian, 616 
Arteriol® rect®, 1423 
Arthrodia, 266 
Arthrology, 259 
Articular arteries of knee, azygos, 
711 
inferior, 711 
superior, 710 
cartilage, 259 
circumference of ulna, 189 
eminence of temporal bone, 84 
lamella of bone, 259 
processes of a vertebra, 49 
synovial membrane, 262 
Articulations, 259 
acromio-clavicular, 299 
of ankle-joint, 347 
astragalo-scaphoid, 354 
atlanto-axial, 276 
of atlas with axis, 274 
with occipital bone, 276 
biaxial, 265 
calcaneo-astragaloid, 352 
-cuboid, 353 
-scaphoid, 353 
carpo-metacarpal, 321 
of carpus, 319 
first row, 319 
second row, 319 
chondro-sternal, 288 
coccygeal, 294 
condyloid, 265 
costo-central, 283 
-chondral, 290 
-sternal, 287 
-transverse, 285 
-vertebral, 283 
crico-arytenoid, 1367 
-thyroid, 1367 
of cuboid with cuneiform, 355 
with scaphoid, 355 
of elbow-joint, 308 
femoro-tibial, 335 
of hip, 325 
immovable, 264 
interchondral, 289 
interneural, 272 
of knee, 334 
of lower extremity, 325 
jaw, 280 
metacarpo-phalangeal, 324 
metatarso-phalangeal, 359 
mixed, 264 
movable, 265 INDEX 
1553 
Articulations, occipito-atlantal, 
276 
-axial, 278 
of ossa pubis, 296 
of ossicles of tympanum, 1160 
of pelvis, 292 
of phalanges of foot, 359 
of hand, 325 
radio-carpal, 317 
-ulnar, 313 
inferior, 315 
middle, 314 
superior, 314 
by reciprocal reception, 265 
of ribs with vertebrae, 283 
sacro-coccygeal, 294 
-iliac, 292 
-sciatic, 292 
-vertebral. 290 
of sacrum with coccyx, 294 
and ilium, 292 
and ischium, 292 
scapulo-clavicular, 299 
of shoulder-joint, 303 
of spine with cranium, 276 
. sterno-clavicular, 297 
of sternum, 290 
tarso-metatarsal, 357 
of tarsus, 352 
temporo-mandibular, 280 
-maxillary, 138 
tibio-fibular, 345 
-tarsal, 347 
of trunk, 269 
of upper extremity, 297 
of vertebral column, 269 
with pelvis, 290 
of wrist, 317 
Arvteno-epiglottidean folds, 
1365 
-epiglottideus muscle, 1373 
Arytenoid cartilages, 1364 
apex of, 1365 
base of, 1365 
surfaces of, 1364 
glands, 1375 
muscles, 1372 
Arytenoideus muscle, 1372 
Ascending aorta, 588 
branches of, 590 
relations of, 589 
cervical artery, 641 
colon, 1309 
flexure of, hepatic, 1309 
frontal artery, 628 
convolution, 872 
lumbar vein, 753, 765 
right, 752 
mesocolon, 1258 
nerve tract, 961 
oblique muscle of abdomen, 
437 
palatine artery, 606 
parietal artery, 628 
convolution, 876 
pharyngeal artery, 610 
ramus of ischium, 212 
of pubis, 213 
root of fifth nerve, 948, 1026 
vena cava, 764 
Association fibres of cerebrum, 
916 
Astragalo-scaphoid articulation, 
354 
ligament, superior, 354 
Astragalus, 244 
articulations of, 245 
body of, 244 
head of, 244 
neck of, 244 
surfaces of, 244, 245 
Asterion, 75, 138 
Atlanto-axial ligament, anterior, 
274 
posterior, 275 
-odontoid joint of Cruveilhier, 
274 
Atlas, 50 
arches of, 51 
attachment of muscles to, 60 
development of, 59 
lateral masses of, 51 
ligament of, transverse, 275 
processes of, 51 
Atlo-axoid ligament, anterior, 
274 
posterior, 275 
Atrabiliary capsules, 1430 
Atria of left bronchus, 1378 
Atrium, 1150 
of nasal fossae, 1100 
meatus, 145 
Attic, 1150 
tympanic, 87 
Attollens auriculam muscle, 369 
relations of, 369 
Attrahens auriculam muscle, 369 
relations of, 369 
Auditory arteries, 1176 
internal, 639 
canal, external, 1148 
meatus, external, 138, 1148 
arteries of, 1149 
cartilaginous portion of, 
1148 
lymphatics of, 1150 
nerves of, 1150 
osseous portion of, 1149 
relations of, 1149 
skin of, 1149 
surface form of, 1150 
veins of, 1150 
internal, 133 
fundus of, 1168 
nerve, 1050 
nuclei of, 925 
origin of, 1050 
roots of, 1050, 1051 
surgical anatomy of, 1054 
nuclei, 950 
accessory, 950 
dorsal, 950 
inner, 950 
ventral, 950 
paths, 1053 
process, 88 
teeth, 1173 
veins, 1176 
Auerbach's plexus, 1299 
Auricle of ear, 1144 
of heart, fibres of, 575 
left, 568 
sinus of, 568 
right, 565 
sinus of, 565 
Auricular appendices, 565 
appendix, left, 568 
right, 565 
artery, anterior, 611 
posterior, 609 
branches of, 610 
branch of pneumogast ric nerve, 
1060 
fissure, 90, 136 
nerves, anterior, 1038 
great, 972 
posterior, 1047 
region, muscles of, 369 
action of, 369 
dissection of, 369 
surface of sacrum, 63 
vein, anterior, 726 
Auricular vein, posterior, 727 
Auriculo-temporal nerve, 1037 
-ventricular groove of heart, 
565 
opening, left, 569 
right, 566 
Axes of pelvis, 218 
Axilla, dissection of, 463 
ligament of, suspensory, 464 
surgical anatomy of, 645 
Axillary arch, 413, 464, 646 
artery, 646 
branches of, 650 
peculiarities of, 649 
relations of, 648 
surface marking of, 649 
surgical anatomy of, 649 
border of scapula, 174 
fascia, 463, 646 
glands, 790 
space, 645 
veins, 747 
surgical anatomy of, 748 
Axis, 52 
apex of, 52 
attachment of muscles to, 60 
body of, 52 
cerebro-spinal, 832 
coeliac, 671 
cylinder of nerve-fibre, 822 
of Purkinje, 822 
development of, 59 
ligament of malleus, 1161 
odontoid process of, 52 
cptic, 1106 
pedicles of, 52 
processes of, 53 
thoracic, 651 
thyroid, 640 
visual, 1106 
Axone of nerve-cells, 821 
Azygos arteries, articular, 711 
of vagina, 6S7 
uvulae muscle, 405 
relations of, 405 
veins, 752 
larger, 752 
left lower, 753 
upper, 753 
right, 752 
smaller, 753 
surgical anatomy of, 753 
B 
Back, fascia of, deep, 411 
superficial, 411 
muscles of, dissection of, 420 
fifth layer, 420 
first layer, 410 
fourth layer, 417 
second layer, 414 
surface forms of, 424 
third layer, 415 
Baillarger, nerve-fibres of, 920 
Band of Gennari, 918 
of Giacomini, 879 
of Meckel, 1160 
Bartholin, duct of, 1217 
glands of, 1482 
Base of brain 881 
of sacrum, 64 
of skull, 130 
surfaces of, 130 
Basi-hyal of hyoid bone, 153 
Basil coil of cochlea, 1167 
Basilar artery, 639 
branches of, 639 
groove, 75 
lymph-sinus, 1306 1554 
INDEX 
Basi'.ar membrane of cochlea, 
1167 
process, 71 
sinus, 743 
suture, 128 
vein, 735 
Basilic vein, 746 
median, 746 
Basis vertebranum, vena*, 753 
Basion, 73 
Basket-cells of cerebellum, 936 
Bauhin, valve of, 1308 
Beak of corpus callosum, 886 
Beaunis et Bouchard, table of 
development of fcetus from, 
1547 
Bechterew, nerve-fibres of, 920 
nucleus of, 926, 1050 
Bell, respiratory nerve of, exter- 
nal, 983 
internal, 974 
Bertin, bones of, 97 
columns of, 1416 
ligament of, 328 
Biaxial articulation, 265 
Biceps flexor cubiti muscle, 475 
muscles, 475, 529 
bursa of, 476 
relations of, 476, 530 
Bichat, fissure of, 900 
Bicipital fascia, 476, 746 
groove, 179 
ridges, 179 
tuberosity, 190 
Bicornate uterus, 1493 
Bicuspid teeth, 1198 
valve, 572 
cusps of, 572 
Bigelow, ligament of, 328 
Bile, 1346 
canaliculi, 1341 
-capillaries, 1341 
-duct, common, 1344 
arteries of, 1346 
dimensions of, 1345 
lymphatics of, 806, 1346 
nerves of, 1346 
structure of, 1345 
surgical anatomy of, 1347 
veins of, 1346 
papilla, 1288 
Bipenniform muscles, 363 
Bipolar cells, 820 
Biventer cervicis muscle, 420 
Biventral lobe of cerebellum, 931 
Bladder, 1431 
apex of, 1435 
arteries of, 1439 
base of, 1435 
body of, 1435 
cervix of, 1435 
female, 1446 
fundus of, 1435 
ligaments of, 1435 
lymphatics of, 802, 1439 
mucous coat of, 1437 
membrane of, 1438 
muscular coat of, 1437 
neck of, 1435 
nerves of, 1440 
serous coat of, 1437 
structure of, 1437 
submucous coat of, 1437 
summit of, 1435 
surface form of, 1440 
surfaces of, 1433 
inner, 1438 
surgical anatomy of, 1440 
trigone of, 1438 
veins of, 1439 
Blade bone, 171 
Blind spot, 1121 
Blood supply of cord, 840 
Blood-vascular system, 555 
Blood-vessels of bone, 39 
Bochdalek, ganglion of, 1033 
Body, carotid, 1409 
cavernous, artery of, 691 
coccygeal, 1410 
pituitary, 882 
thyroid, 1401 
of a vertebra, 49 
Bones, acetabulum, 213 
apophysis of, 34 
areolte of, primary, 44 
secondary, 45 
astragalus, 244 
atlas, 50 
axis, 52 
of Bertin, 97 
blood-vessels of, 39 
breast, 155 
calcaneum, 242 
canaliculi of, 46 
cancellous, 35 
carpus, 193 
chemical composition of, 41 
clavicle, 167 
coccyx, 65 
compact, 35 
cranial, 71 
cuboid, 245 
cuneiform of, foot, 247 
of hand, 197 
diploe of, 34 
ear, 1158 
eminences and depressions of, 
34 
epactal, 103 
epicteric, 103 
epiphysis of, 34 
ethmoid, 98 
of face, 104 
femur, 221 
fibula, 237 
flat, 34 
of foot, 239 
frontal, 79 
growth of, 42 
of hand, 193 
Haversian canals of, 38 
systems of, 38 
humerus, 177 
hyoid, 153 
ilium, 207 
incus, 1158 
inter-maxillary, 110 
irregular, 34 
ischium, 210 
of jaw, upper, changes pro- 
duced in, by age, 112 
lachrymal, 112 
lacunse of, 38 
lamella of, 38 
articular, 259 
of leg, 230 
lingual, 153 
long, 33 
lymphatics of, 41 
malar, 113 
malleus, 1158 
marrow of, 36 
maxillary, inferior, 122 
superior, 105 
medullary spaces of, 45 
metacarpal, 200 
metatarsal, 249 
mixed, 34 
nasal, 104 
navicular, 195, 246 
nerves of, 41 
occipital, 71 
Bones, orbicular, 1159 
os calcis, 242 
innominatum, 207 
magnum, of carpus, 199 
ossification of, 42 
intracartilaginous, 43 
intramembranous, 43 
palate, 115 
parietal, 76 
patella, 230 
pelvic, 215 
periosteum of, 37 
phalanges of foot, 252 
of hand, 204 
pisiform, 197 
ploughshare, 120 
pre-maxillary, 110 
pubis, 212 
radius, 190 
ribs, 159 
sacrum, 61 
scaphoid, of foot, 246 
of hand, 195 
scapula, 171 
semilunar, 196 
sesamoid, 257 
short, 33 
sphenoid, 92 
spongy, 97 
sternum, 155 
structure of, 34 
supernumerary, 103 
surface of, 34 
sutural, 103 
tarsus, 242 
temporal, 83 
thigh, 221 
tibia, 233 
trapezium, 198 
trapezoid, 198 
turbinated, inferior, 119 
middle, 101 
sphenoidal, 143 
superior, 101 
tympanic 91 
ulna, 184 
unciform, 199 
veins of, 41 
vertebra prominens, 53 
vertebrae, cervical, 49 
dorsal, 53 
lumbar, 56 
thoracic, 53 
vomer, 120 
wedge, 247 
Wormian, 103 
Bony canal of cochlea, 1167 
Bosom, 1503 
Bowman's capsule, 1418 
glands of, 1101 
membrane, 1109 
muscle, 1115 
Brachia of corpora quadrigemina, 
911 
Brachial artery, 652 
branches of, 655 
peculiarities of, 653 
relations of, 652 
surface marking of. 654 
surgical anatomy of, 654 
lymphatic glands, 788 
plexus, 977 
branches of, 981 
relations of, 980 
surgical anatomy of, 991 
region, anterior, musc.es of,479 
posterior, muscles of, 486 
veins, 747 
Brachialis anticus muscle, 476 
relations of, 476 
Brachio-cephalic vein, 750 INDEX 
1555 
Brachium, 904 
Brain, 857 
arteries of, cortical, 631 
base of, 881 
blood-vessels of, 629 
capsule of, external, 894 
internal, 894 
commissures of, 903 
communication of the parts of, 
863 
convolutions of, 865 
development of, 857 
dissection of, 847 
dura mater of, 847 
ganglionic vessels of, central, 
630 
general considerations and di- 
visions of, 864 
gyri of, 865 
hemispheres of, 864 
surfaces of, under, 881 
infundibulum of, 882 
little, 926 
lobes of, 872 
membranes of, arachnoid, 851 
meninges of, 847 
pia mater of, 854 
sand, 906 
ventricle of, fifth, 897 
lateral, 888 
third, 901 
Vergas, 896 
weight of, 951 
Breast bone, 155 
Bregma, 129 
Bregmatic fontanelle, 103 
Breschet, canals of, 733 
Brim of pelvis, 217 
Broad ligaments of liver, 1333 
of uterus, 1490 
Broca, area of, 881 
"cap" of, 874 
convolution of, 874 
Bronchi, 1376 
relations of, 1376 
Bronchial arteries, 666 
branch of innominate, 594 
glands, 1380 
septum, 1380 
veins, 753 
Bronchus, left, 1378 
right, 1376 
Brown striae of Retzius, 1204 
Bruch, membrane of, 1114 
Brunner's glands, 1295 
Bruns, falciform margin of, 515 
space of, 388 
Bubonocele, 1521 
Buccal artery, 615 
cavity, 1193 
glands, 1195 
lymphatic glands, 782 
nerve, 1037, 1049 
Buccinator crest, 124 
glands, 782 
muscle, 380 
relations of, 380 
nerve, 1037 
Bucco-pharvngeal fascia, 380, 
388, 401, 1222 
Bulb, artery of, 691 
surgical anatomy of, 691 
of corpus cavernosum, 1456 
spongiosum, 1457 
of internal jugular vein, 729 
nerve to, 1013 
olfactory, 880, 1019 
spinal, 938 
of urethra, male, 1458 
vaginal, 1483 
Bulbar arteries, 639 
Bulbar portion of conjunctiva, 
1140 
of spinal accessory nerve, 
1063 
Bulbi vestibuli, 1483 
Bulbo-cavernous muscle, 457 
Bulla ethmoidalis, 145, 1099 
Bundle of Vicq d'Azyr, 883 
Burdach, tract of, 839, 843 
Bursae of ankle, 543 
anserina, 530 
of biceps muscle, 476 
of coraco-brachialis muscle, 
475 
of elbow, 311 
of extensor carpi radialis bre- 
vior muscle, 486 
of foot, 543 
of gastrocnemius muscle, 534 
of great trochanter, 331 
gluteo-femoral, 331 
of hand, 492 
of hip, 330 
iliac, subtendinous, 331 
ilio-pectineal, 330 
infrapatellar, deep, 340 
infraspinatus, 305, 473 
ischio-gluteal, 331 
of knee, 340 
of latissimus dorsi muscle, 474 
obturator, 331 
internus muscle, 525 
olecranon, 311 
subcutaneous, 477 
ovarian, 1490 
patellar, 518 
pharyngeal, 1224 
prepatellar, 340 
of pyriformis muscle, 525 
of semimembranous muscle, 
531 
of shoulder, 305 
sterno-hyoid, 391 
subacromial, 305, 471 
subcutanea prominent iae laryn- 
gea?, 1362 
subcutaneous acromial, 305 
trochanteric, 331 
subdeltoid, 305, 471 
subscapular, 305, 472 
suprapatellar, 340 
synovial, subcutaneous, 263 
subtendinous, 263 
of tendo Achillis, 535 
tibial, subcutaneous, 340 
of tibialis anticus muscle, 532 
wrist, 492 
Bursal synovial membrane, 263 
C 
C.ecal fold, inferior, 1264 
superior, 1263 
Caecum, 1300 
arteries of, 1305 
interior of, 1303 
lymphatics of, 1306 
supports of, 1302 
veins of, 1306 
vestibulare, 1170 
Caelum, 1236 
Cajal, horizontal cells of, 1125 
neurones of, 919 
Calamus scriptorius, 943 
Calcaneal nerves, external, 1014 
internal, 1015 
Calcanean artery, external, 718 
internal, 719 
Calcaneo-astragaloid ligament, 
external, 352 
Calcaneo-astragaloid ligament, 
internal, 352 
posterior, 352 
-cuboid ligament, internal, 353 
long, 353 
short, 353 
superior, 353 
-navicular ligament, 353 
-plantar nerve, 1015 
-scaphoid ligament, external, 
353 
inferior, 354 
internal, 354 
superior, 353 
Calcaneus, 242 
anterior extremity of, 242 
articulations of, 244 
attachment of muscles to, 244 
body of, 242 
posterior extremity of, 242 
process of, greater, 243 
lesser, 243 
surfaces of, 242, 243 
tuberosity of, 243 
Calcar avis, 889 
femorale, 227 
Calcarine fissure, 870 
Calf bone, 237 
Calices of kidney, 1415 
Callosal convolution, 879 
sulcus, 879, 885 
Calloso-marginal sulcus, 870 
Calvaria, 71 
Camper, fascia of, 433 
Canalis centralis cochleae, 89 
reuniens of Hensen, 1170 
spiralis modioli, 1169 
Canaliculi of bone, 46 
Canaliculus tympanicus, 1151 
Canals, acoustic, external, 1148 
• adductor, 698 
Alcock's, 1011, 1536 
alimentary, 1193 
anal, 1315 
of appendix, 1304 
for Arnold's nerve, 90 
auditory, 1148 
of Breschet, 733 
carotid, 136 
central, of cord, 840 
cervical, 1491 
for chorda tympani, 8 
of Cloquet, 1129 
of cochlea, 1167 
membranous, 1172 
crural, 1531 
dental, 1202 
anterior, 107 
inferior, 324 
posterior, 106 
diploic, 733 
ethmoidal, 82, 100 
for Eustachian tube, 1154 
fascial, 1536 
femoral, 509, 1531 
Haversian, 38 
of Huguier, 84, 1047 
Hunter's, 521, 698 
hyaloid, 1129 
incisor, 110 
infraorbital, 107, 140 
inguinal, 448, 1517 
for Jacobson's nerve, 90 
lachrymal, 1142 
malar, 114 
medullary, 857 
naso-palatine, 121 
neural, 857 
neurenteric, 1242 
of Nuck, 1462, 1501 
obturator, 525 1556 
INDEX 
Canals, palatine, anterior, 143 
posterior, 107, 116 
accessory, 116, 135 
palato-maxillary, 107 
of Petit, 1130 
pterygo-palatine, 135 
pterygoid, 135 
sacral, 64 
of Schlemm, 1108, 1111 
semicircular, 1165 
spermatic, 448, 1517 
spinal, 69 
of Stilling, 1129 
for tensor tympani, 91, 1153 
vertebral, 49 
Vidian, 96, 135 
Volkmann's, 38 
of Wirsung, 1351 
Cancellous bone, 35 
lamellte of, 39 
Canine eminence, 106 
fossa, 106, 140 
teeth, 1197 
Canthi of eyelids, 1138 
^'Cap" of Broca, 874 
Capillaries, histology of, 584 
Capitellum of humerus, 181 
Capsula extrema, 894 
Capsular ligaments. See Indi- 
vidual joints. 
■Capsules, atrabiliary, 1430 
Bowman's, 1418 
of brain, external, 894 
internal, 892 
fibres of, 892 
cartilage, 260 
of Glisson, 770, 1256, 1337 
of kidneys, fatty, 1411 
true, 1415 
of lens, 1130 
parotid, 1216 
of prostate gland, 1449 
suprarenal, 1428 
of T^non, 1103 
Caput, cornu of cord, 839 
gallinaginis, 1442 
Cardia, 1270 
Cardiac depression of liver, 1327 
ganglion of Wrisberg. 1081 
glands, 1278 
lymphatics, 815 
muscular fibres, 361 
nerve, cervical, 1061 
great, 1077 
inferior, 1077 
middle, 1077 
minor, 1077 
superior, 1076 
thoracic, 1061 
orifice of stomach, 1270 
plexus of nerves, 1081 
anterior, 1081 
deep, 1081 
great, 1081 
superficial, 1081 
portion of stomach, 1269 
veins, 770 
anterior, 771 
great, 770 
left, 771 
middle, 771 
posterior, 771 
right, 771 
Cardio-motor nerves, 1071 
Carina urethralis vaginae, 1484 
Carotico-tympanic nerve, 1073 
Carotid arteries, common, 595 
branches of, occasional, 
598 
peculiarities of, 598 
relations of, 596 
Carotid arteries, common, sur- 
face form of, 598 
surgical anatomy of, 598 
external, 600 
branches of, 601 
relations of, 600 
surface form of, 601 
surgical anatomy of, 601 
internal, 619 
branches of, 621 
cavernous portion, 621 
cerebral portion, 621 
cervical portion 620 
peculiarities of, 621 
petrous portion, 620 
relations of, 620 
surgical anatomy of, 621 
body, 1409 
canal, 136 
foramen, external, 89 
internal, 88 
ganglion, 1073 
gland, 786, 1409 
surgical anatomy of, 1409 
groove, 93 
nerves, 1057 
plexus, 1073 
sheath, 388 
triangle, inferior, 616 ' 
superior, 394, 617 
tubercle, 51 
Carpal arch, anterior, 659 
posterior, 659 
artery, radial, anterior, 659 
posterior, 659 
ulnar, anterior, 663 
posterior, 663 
bones, development of, 205 
Carpo-metacarpal articillations, 
321 
Carpus, 193 
articulations of, 319 
first row, 319 
second row, 319 
common characters of, 193 
ligaments of, 319 
surface form of, 204 
surgical anatomy of, 204 
Cartilage, 259 
accessory quadrate, 1097 
alar, 1097 
of aperture of nose, 1097 
articular, 259 
arytenoid, 1364 
capsule, 260 
costal, 164 
cricoid, 1363 
cuneiform, 1365 
of ear, 1146 
elastic, 260 
ensiform, 155 
of epiglottis, 1365 
epiphysial, 36, 44 
fibro-, 260 
hyaline, 259 
intrathyroid, 1363 
of Jacobson, 1097 
of larynx, 1362 
of nose, 1096 
permanent, 259 
of pinna, 1146 
of Santorini, 1365 
sesamoid, 1097 
spaces, 260 
temporary, 259 
thyroid, 1362 
of trachea, 1378 
triangular, of septum of nose, 
1097 
vomerine, 1097 
of Wrisberg, 1365 
Cartilage, xiphoid, 155 
Cartilaginous isthmus of pinna, 
1146 
portion of Eustachian tube, 
1154 
of external auditory meatus 
1148 
Cartilago triticea, 1365 
Caruncle, lachrymal, 1142 
Caruncula lacrimalis, 1140 
major of Santorini, 1288 
minor of Santorini, 1288 
Carunculae mystiformse, 1482 
Casserius, perforating nerve of, 
985 
Cauda equina, 1006 
helicis, 1146 
Caudal gut, 1242 
Caudate lobe of liver, 1333 
nucleus, 891 
bulb of, 891 
head of, 891 
surcingle of, 891 
tail of, 891 
Cava, ascending, 764 
inferior, 764 
peculiarities of, 764 
superior, 752 
Cave of Meckel, 848 
Cavernous body, artery of, 691 
groove, 93 
nerves of penis, 1086 
plexus, 1073 
portion of internal carotid 
artery, 621 
of urethra, 1443 
sinus, 739 
surgical anatomy of, 740 
Cavity, buccal, 1193 
of cervix uteri, 1491 
cotyloid, 213 
glenoid, 175 
of larynx, 1368 
of Meckel, 848 
of mouth, 143 
nasal, 142 
oral, 1193 
of pelvis, 1431 
pericardiothoracic, 1236 
of pleura, 1382 
pleuroperitoneal, 1236 
sigmoid, of radius, 191 
of ulna, 186 
of thorax, 556 
of tunica vaginalis, 1470 
tympanic, 1150 
of uterus, 1491 
Cavum conchae, 1145 
Meckelii, 1027 
oris proprium, 1193 
Cells, amacrine, 1125 
basket, 936 
bipolar, 820 
centro-acinar, of Langerhans, 
1352 
of Claudius, 1175 
column, lateral, 846 
of Deiters, 1175 
enamel, 1206 
ethmoidal, 82, 100 
posterior, 145 
of Golgi, 821 
gustatory, 1091 
of Hensen, 1175 
hepatic, 1338 
horizontal, of Cajal, 1125 
of Martinotti, 921 
mastoid, 86 
multipolar, 820 
nerve, 820 
axone of, 821 INDEX 
1557 
Cells, nerve, dendrites of, 821 
development, of, 823 
epithelium, 830 
olfactory, 1101 
oxyntic, 1277 
parietal, 1277 
peptic, of glands, 1277 
prickle, 1109 
of Purkinje, 925 
of Sertoli, 1472 
sphenoidal, 94 
unipolar, 820 
Cementum of teeth, 1204 
development of, 1207 
Central canal of cord, 840 
coil of cochlea, 1167 
ganglionic vessels of brain, 630 
lobe of cerebrum, 878 
sulcus of Rolando, 867 
tendon of diaphragm, 429 
Centrifugal projection fibres of 
cerebrum, 914 
Centripetal projection fibres of 
cerebrum, 914 
Centro-acinar cells of Langer- 
hans, 1352 
Centrum ovale majus of Vieus- 
sens, 886 
minus, 885 
vertebra, 48 
Cephalic vein, 747 
median, 746 
Cephalo-auricular angle, 1144 
Cerato-hyals of hyoid bone, 154 
Cerebellar arteries, anterior in- 
ferior, 640 
posterior inferior, 639 
superior, 640 
columns, 841 
notch, anterior, 926 
posterior, 926 
tract, antero-lateral, ascend- 
ing, 842 
descending, 843 
direct, 843 
dorso-lateral, 843 
path of, 963 
veins, deep, 736 
superficial, 736 
inferior, 736 
superior, 736 
Cerebellum, 926 
amygdala of, 931 
corpus dentatum of, 937 
cortex of, 936 
fibres of, 932 
proper, 936 
fissures of, 927 
fraenulum of, 928 
ganglion of, 937 
gray matter of, 936 
hemispheres of, 885, 926 
lamina of, 927 
lobes of, 926, 928 
nodules of, 930 
peduncles of, 932, 943 
superior, 910 
structure of, internal, 931 
surfaces of, inferior, lobes on, 
930 
under, 929 
upper, 927 
tonsil of, 931 
uvula of, 931 
vallecula of, 926 
vermiform process of, 926 
weight of, 938 
white matter of, 931 
Cerebral artery, anterior, 626 
branches of, 626 
middle, 627 
Cerebral arterv, middle, branches 
of, 628' 
posterior, 640 
convolutions, 857 
cranium, 71 
hemorrhage, arteries of, 628 
localization, 953 
lymphatic vessels, 779 
nerves, 1019 
peduncles, 906 
portion of internal carotid 
artery, 621 
veins, 734 
cortical, 735 
deep, 735 
inferior, 735 
median, 735 
superficial, 735 
superior, 735 
ventricles, 888 
Cerebro-cortico-pontal nerve 
paths, 960 
Cerebro-spinal axis, 832 
nervous system, structure 
of, 817 
Cerebrum, commissure of, ante- 
rior, 896 
fibres of, 914 
fissures of, longitudinal, 865, 
882 
gray matter of, 918 
hemispheres of, 864 
constituent parts of, 864 
general considerations of, 
864 
surface of, 865 
external, lobes on, 869 
mesial, fissures of, 869 
sulci of, 869 
outer, fissures of, 865 
sulci of, 865 
tentorial, fissures of, 869 
sulci of, 869 
interior of, 885 
parts composing, 885 
peduncles of, 882, 884 
structure of, 913 
ventricles of, 888, 900, 901 
white matter of, 913 
Ceruminous glands, 1149 
Cervical artery, ascending, 641 
deep, 646 
superficial, 642 
transverse, 642 
canal, 1491 
cardiac nerves, 1061 
fascia, deep, 387 
superficial, 386 
surgical anatomy of. 389 
ganglion, inferior, 1077 
branches, central commu- 
nicating, 1077 
peripheral, 1077 
middle, 1076 
branches of, central com- 
municating, 1076 
peripheral, 1077 
superior, 1072 
branches of, 1073 
central, 1073 
communicating, 1073 
peripheral, 1073 
surgical anatomy of, 1077 
glands, deep, 786 
accessory chains to, 787 
lower, 787 
upper, 786 
superficial, 784 
anterior, 784 
nerves, 968 
divisions of, anterior, 971 
Cervical nerves, divisions of, 
dorsal, 968 
from facial nerve, 1049 
posterior, 968 
roots of, 968 
superficial, 973 
pleura, 1385 
plexus, 972 
branches, deep, 974 
superficial, 972 
posterior, 970 
surgical anatomy of, 977 
portion of internal carotid 
artery, 620 
of oesophagus, 1226 
region, superficial, muscles of, 
386 
rib, 53 
veins, anterior deep, 733 
posterior deep, 733 
vertebra, seventh, 53 
vertebra*, 49 
lamina* of, 49 
body of, 49 
pedicles of, 49 
processes of, 50 
Cervicalis ascendens muscle, 419 
Cervico-facial nerve, 1049 
Cervix of bladder, 1435 
cornu of cord, 839 
uteri, 1488 
cavity of, 1491 
Chassaignac's tubercle, 69 
Check ligaments, 278 
of eye, 1105 
Cheeks, 1195 
mucous membrane of, 1195 
surgical anatomy of, 1224 
Chemical composition of bone, 
41 
of nervous tissue, 824 
Chest, 155 
articulations of, 159 
attachment of muscles to, 159 
boundaries of, 155 
development of, 158 
structure of, 158 
surface form of, 156 
surgical anatomy of, 165 
Chiasma or optic commissure, 
1021 
Chink of glottis, 1369 
Choante, 146 
Chondro-glossus muscle, 397 
-sternal ligament, anterior, 
288 
interarticular, 288 
posterior, 288 
-xiphoid ligament, anterior, 
288 
posterior, 288 
Chorda tympani nerve, 1047 
Chorda* tendinese of left ventri- 
cle, 573 
of right ventricle, 570 
Willisi, 737 
Choroid arteries, anterior, 628 
posterior, 640 
coat of eye, 1111 
structure of, 1112 
fissure, 890, 900 
nerves of, 1120 
plexus, 899 
of body of ventricle, 900 
of fourth ventricle, 901 
of lateral ventricle, 900 
of third ventricle, 901 
vein, 735 
Chromatophile granules, 820 
Chyli receptaculum, 624 
Cilia, or eyelashes, 1137 1558 
INDEX 
Ciliary arteries, anterior, 625 
long, 625 
short, 625 
body, 1115 
ganglion, 1031 
long root of, 1030 
glands, 1190 
ligament, 1116 
margin, 1117 
muscles, 1115 
nerves, long, 1030 
short, 10.0 
processes of eye, 1115 
structure of, 1115 
Cingulum, 879, 918 
Circle of Willis, 629, 640 
Circular sinus, 742 
Circulus of iris, major, 625 
minor, 625 
tonsillaris, 1036 
Circumanal glands, 1190 
Circumduction, 274 
Circumflex arteries of arm, 651 
of thigh, 705 
iliac artery, deep, 697 
superficial, 704 
vein, deep, 759 
nerve, 984 
lower branch, 985 
upper branch, 985 
vein, deep, 758 
superficial, 756 
Circumflexus muscle, 404 
relations of, 404 
Circumpatellar anastomosis, 711 
Circumvallate papillae of tongue, 
1089 
Cistern of Pecquet, 775 
Cisterna basalis, 852 
magna, 853 
pontis, 853 
Clado, appendiculo-ovarian lig- 
ament of, 1304 
Clarke, vesicular column of, 
843 
Claudius, cells of, 1175 
Claustrum, 894 
Clava of fasciculus gracilis, 941 
Clavicle, 167 
articulations of, 170 
attachment of muscles to, 
170 
development of, 170 
peculiarities of, in sexes and 
individuals, 170 
structure of, 170 
surface form of, 170 
surgical anatomy of, 170 
Clavicular facet, 157 
Clavi-pectoral fascia, 467 
Clinoid process, anterior, 131 
middle, 93, 132 
posterior, 93, 132 
Clitoris, 1479 
arteries of, 1480 
crus of, 1480 
fraenum of, 1479 
muscles of, 461 
nerves of, 1480 
dorsal, 1013 
prepuce of, 1479 
Clivus, 93 
monticuli of cerebellum, 928 
Cloquet, canal of, 1129 
gland of, 795, 798 
ligament of, 1466 
septum crurale of. 509 
Coccygeal artery, 693 
body, 1410 
gland, 1410 
ligament, 833 
Coccygeal nerve, divisions of, an- 
terior, 1009 
posterior, 1008 
Coccygeus muscle, 455 
Coccyx, 65 
apex of, 66 
articulation of, 67 
attachment of muscles to, 67 
base of, 66 
borders of, 66 
cornua of, 66 
development of, 66 
surfaces of, 66 
Cochlea, 1165 
canal of, bony, 1167 
membranous, 1172 
spiral, 1167 
lamina spiralis of, 1167 
ligament of, spiral. 1172 
nerve, 1053 
Cochlear artery, 1126 
path, 1053 
root of eighth nerve, 1051 
window, 1152 
Cceliac artery, 671 
axis, 671 
glands, 800 
plexus, 1061, 1084 
Colic area of kidneys, 1414 
artery, left, 678 
middle, 676 
right, 675 
glands, 808 
impression of liver, 1329 
plexus, 1085 
Collar bone, 167 
Collateral fissure, 871 
intercostal artery, 668 
Colles' fascia, 456, 1515 
ligament, 437 
Colliculus nervi optici, 1364 
Colloid material. 1404 
Colon, 1309 
ascending, 1309 
descending, 1309 
pelvic, 1311 
sigmoid, 1311 
surgical anatomy of, 1326 
transverse, 1309 
Colostrum corpuscles, 1507 
Columella cochlea?, 1166 
Column of Marchi and Lowen- 
thal, 843 
Columna nasi, 1096 
Columns* cameae of left ventricle, 
573 
of right ventricle, 570 
Columns of Bertin, 1416 
cerebellar, 843 
of Morgagni, 1319 
of spinal cord, 838 
of vagina, 1484 
Comes nervi ischiadici artery, 693 
mediana artery, 663 
phrenici artery, 644 
Comma tract, descending, 844 
Commissura hippocampi, 896 
Commissural fibres of cerebrum, 
916 
Commissure of brain, anterior,896 
gray, 903 
middle, 903 
posterior, 903 
soft, 903 
Gudden's, 912, 1021 
of habenula, 904 
of Meynert, 908 
optic,'131, 882, 1021 
of spinal cord, 839 
anterior, 839 
gray, 839 
Commissure of spinal cord, gray, 
anterior, 839 
posterior, 839 
posterior, 839 
white, 839 
Common carotid artery, 595 
facial vein, 726 
femoral artery, 699 
iliac arteries, 681 
glands, 799 
vein, 764 
temporal vein, 727 
ulnar vein, 745 
Communicantes hvpoglossi nerve, 
974 
Communicating arteries, ante- 
rior cerebral, 627 
posterior cerebral, 628 
of ulnar, anterior, 662 
Compact bone, 35 
longitudinal section of, 39 
transverse section of, 38 
Complexus muscle, 420 
relations of, 420 
Compressor narium minor mus- 
cle, 376 
sacculi laryngis, 1373 
urethrae muscle in female, 462 
in male, 460 
Conarium, 905 
Concentric lines of Schreger, 1203 
Concha auricula?, 1145 
Conducting tracts of cord, 841 
Conductor sonorus, 945 
Condyles of bones. See Bones. 
Condylic portion of occipital 
bone, 71 
Condyloid articulation, 265 
foramen, anterior, 73, 133, 136 
posterior, 73, 133, 136 
fossa, anterior, 136 
posterior, 136 
glands of Leaf, 795 
process, 125 
Cone-bipolars, 1125 
-granules of retina, 1126 
Cones of retina, 1126 
Congenital hernia, 1523 
Conglobate glands, 774 
Conical papilla*, 1090 
Conjugate diameter of pelvis, 217 
Conjunctiva, 1140 
bulbar portion of, 1140 
fornix of, 1140 
glands of, 1140 
nerves of, 1140 
palpebral portion of, 1140 
surgical anatomy of, 1144 
Connective tissue, subserous, 
1246 
Conoid ligament, 300 
tubercle, 168 
Constriction lobe of liver, 1336 
Constrictor isthmi faucium mus- 
cle, 398, 405 
muscles, inferior, 400 
middle, 401 
superior, 401 
urethrae muscle in female, 462 
in male, 460 
Conus arteriosus, 569 --- 
terminalis, 837 
Convolutions, angular, 876 
of brain, 865 
of Broca, 874 
callosal, 879 
dentate, 879 
frontal, 872 
hippocampal, 879 
of limbic lobe, 879 
marginal, 873 INDEX 
1559 
Convolutions, occipital, 877 
occipito-temporal, 878 
orbital, internal, 873 
parietal, 876 
ascending, 876 
post-parietal, 876 
precuneus, 877 
quadrati, 877 
subcalcarine, 877 
subcollateral, 878 
supramarginal, 876 
temporal, 877 
uncinate, 879 
Cooper, ligament of, 437, 448 
Coraco-acromial ligament, 301 
-brachialis muscle, 475 
bursa of, 475 
relations of, 475 
-clavicular ligament, 300 
-humeral ligament, 304 
Coracoid ligament, 302 
process, 175 
Cord, gangliated, 1071 
cervical portion of, 1071 
lumbar portion of, 1079 
pelvic portion of, 1080 
sacral portion of, 1080 
thoracic portion of, 1078 
spermatic, 1466 
spinal. See Spinal cord, 
vocal, 1370 
Cordiform tendon of diaphragm, 
429 
Corium, 1180 
corpus papillare of, 1181 
of tongue, 1089 
Cornea, 1108 
arteries of, 1111 
nerves of, 1111 
structure of, 1109 
Corneal endothelium, 1111 
spaces, 1110 
Comical tubercle of Santorini, 
1368 
Cornicula laryngis, 1365 
Cornu ammonis, 897 
commissural tract, 844 
of lateral ventricle, 889 
Cornua of coccyx, 66 
of hyoid bone, 154 
sacral, 62 
Corona ciliaris, 1115 
glandis, 1454 
Coronal suture, 78, 127 
Coronary artery, 671 
of heart, 590 
descending, 590 
infundibular, 590 
marginal, 590 
peculiarities of, 591 
transverse, 590 
of lip, inferior, 607 
superior, 607 
of stomach, 671 
ligament of knee, 340 
of liver, 1334 
plexus, 1085 
anterior, 1081 
left, 1081 
posterior, 1081 
right, 1081 
sinus, 567, 771 
valve, 567 
vein, 768 
left, 770 
small, 771 
Coronoid fossa, 181 
process of jaw, 125 
of ulna, 186 
Corpora albicantia, 883 
bigemina, 911 
Corpora cavernosa, 1455 
arteries of, 1458 
bulb of, 1456 
structure of, 1457 
trabecula? of, 1457 
veins of, 1458 
geniculata, 911 
mammillaria, 883 
peduncles of, 883 
quadrigemina, 907, 911 
brachia of, 119 
structure of, 911 
Corpus albicans, 895 
Arantii, 571, 573 
callosum, 882, 886 
beak of, 886 
body of, 886 
pad of, 886 
peduncles of, 882, 886 
rostrum of, 886 
splenium of, 886 
cavernosum, artery of, 691 
dentatum of cerebellum, 937 
of olive, 951 
fimbriatum, 890, 896, 898 
of olivary body, 951 
papillare of cerium, 1181 
spongiosum, 1458 
structure of, 1458 
striatum, 890 
Corpuscles of Herbst, 829 
Malpighian, of kidney, 1417 
of spleen, 1358 
Pacinian, 828 
of Purkinje, 936 
tactile, 827 
of Vater, 828 
Corrugator cutis ani muscle, 
449 
supercilii muscle, 371 
relations of, 371 
Cortex of cerebellum, 936 
of cerebrum, cells of, 919 
gray matter of, 918 
nerve-fibres of, 920 
Corti, ganglion of, 1053 
membrane of, 1175 
organ of, 1173 
rods of, 1174 
tunnel of, 1174 
Cortical arteries of brain, 631 
cerebral veins, 735 
portion of kidney, 1416 
of suprarenal capsule, 1430 
of thymus gland, 1408 
substance of teeth, 1204 
Costal cartilages, 164 
attachment of muscles to, 
164 
borders of, 164 
extremities of, 164 
surfaces of, 164 
facet, 169 
pleura, 1385 
process, 50 
surface of lungs, 1391 
Costo-axillary vein, 748 
-central articulations, 283 
-chondral articulations, 290 
-clavicular ligament, 298 
-coracoid ligament, 467 
membrane, 467 
-mediastinal sinus, 1386 
-sternal articulations, 287 
-transverse articulations, 285 
foramen, 50 
ligament, long, 285 
middle, 286 
posterior, 286 
-vertebral articulations, 283 
ligament, anterior, 284 
I Costo-xiphoid ligament, ante- 
rior, 288 
posterior, 288 
Cotunnis, nerve of, 1036 
Cotyloid cavity, 213 
ligament, 329 
notch, 213 
Cowper's glands, 1453 
structure of, 1453 
Cranial bones, 71 
fossa, 143 
nerves, 1019 
path of, 962 
reflex, 963 
region, dissection of, 366 
fascia of, superficial, 366 
lymphatics of, 779 
vessels of, 782 
sutures, 127 
Cranio-cerebral topography, 954 
Cranium, 71 
cerebral, 71 
development of, 102 
differences in size and form of, 
146 
fasciae of, 365 
lymphatics of, 779 
membranous, 102 
muscles of, 365 
Cremaster muscle, 439, 1516 
Cremasteric artery, 696 
fascia, 1464, 1516 
Crescentric lobe, anterior, 928 
posterior, 928 
Crescents of Gianuzzi, 1218 
Crest, buccinator, 124 
ethmoidal, 94 
falciform, 89 
frontal, 80, 130 
incisor, 111 
infratemporal, 95 
lachrymal, 113 
bone, 141 
nasal, 111, 116 
obturator, 213 
occipital, external, 72, 136 
internal, 74, 133 
sphenoidal, 94 
supramastoid, 84, 137 
temporal, 76, 80, 84 
of tibia, 234 
turbinated, inferior, 107, 117 
superior, 117 
Cribriform fascia, 512, 1527 
lamina, 1108 
plate, 130 
of ethmoid, 99 
Cric o-arytenoid articulation, 
1367 
ligaments, 1367 
muscle, lateral, 1373 
posterior, 1372 
-thyroid artery, 602 
articulation, 1367 
membrane, 1367 
muscle, 1372 
-tracheal ligament, 1368 
Cricoid cartilage, 1363 
borders of, 1364 
surfaces of, 1364 
Crista falciformis, 89 
galli, 99, 130 
terminalis, 565 
vestibuli, 1164 
Crossed descending tract, 842 
pyramidal tract, 842 
Crucial ligaments of knee, 337 
Cruciform ligament, 275 
Crura ad cerebrum, 932 
ad medullam, 934 
ad posterior, 934 1560 
INDEX 
Crura cerebri, 884 
of diaphragm, 427 
of penis, 1454 
Crural arch, deep, 448, 1531 
superficial, 436, 1529 
canal, 509, 1531 
nerve, anterior, 1004 
ring, 437, 509, 1532 
septum, 1532 
sheath, 509 
Crureus muscle, 517 
nerve to, 1006 
relations of, 517 
Crus cerebri, tegmentum of, 
885 
of helix, 1145 
Crusta of crus cerebri, 907 
petrosa of teeth, 1204 
Cruveilhier, atlanto-odontoid 
joint of, 274 
glenoid ligament of, 359 
Crypts of Lieberkuhn, 1295 
of Morgagni, 1319 
Crystalline lens, 1130 
capsule of, 1130 
substance of, 1130 
structure of, 1131 
Cuboid bone, 245 
articulations of, 246 
attachment of muscles to, 
246 
surfaces of, 245, 246 
tuberosity of, 245 
Culmen monticuli cert belli, 
928 
Cuneate funiculus, 941 
lobe, 877 
nucleus, accessory, 948 
tubercle, 941 
Cuneiform bone, foot, 247 
external. 248 
articulations of, 249 
attachment of muscles 
to, 249 
surfaces of, 248 
internal, 247 
articulations of, 247 
attachment of muscles 
to, 247 
surfaces of, 247 
middle, 248 
articulations of, 248 
attachment of muscles 
to, 248 
surfaces of, 248 
of hand, 197 
articulations of. 197 
surfaces of, 197 
cartilages, 1365 
tubercle of Wrisberg, 1368 
Cuneus, 875 
Cupola of cochlea, 1167, 1172 
Cushion of epiglottis, 1365 
Cusps of bicuspid valve, 572 
of tricuspid valve, 570 
Cutaneous nerve, external, 985, 
1003 
internal, 986, 1004 
middle, 1004 
palmar, 987 
perforating, 1011 
Cuticle of skin, 1181 
Cutis vera, 1180 
Cuvier, duct of, 561 
Cymba conchae, 1145 
Cystic artery, 674 
duct, 1344 
plexus of nerves, 1085 
vein, 769 
Czermak, interglobular spaces of, 
1202 
D 
Dacryon, 141 
Dart os of scrot um, 1463 
Darwin, tubercle of, 1145 
Deciduous teeth, 1196 
Decussatio nervorum trochlea- 
rium, 1025 
Decussation of fillet, 949 
of pyramids, 947 
Deep annectant gyrus, 867 
anterior thoracic nerve, 984 
branches of cervical plexus, 
974, 976 
cardiac plexus, 1081 
cerebral veins, 735 
cervical artery, 646 
fascia, 387 
glands, 786 
circumflex iliac artery, 697 
vein, 759 
crural arch, 448, 1531 
dorsal vein of penis, 762 
epigastric artery, 696 
vein, 759 
external pudic artery, 704 
fascia, 364 
of arm, 470, 474 
of back, 411 
of femoral region, anterior, 
513 
of forearm, 478 
of leg, 532 
of shoulder, 470 
of thoracic region, anterior, 
463 
femoral artery, 704 
lymphatic glands, 795 
inguinal lymphatic glands, 795 
lymphatic glands of upper ex- 
tremity, 790 
vessels of abdominal wall, 
801 
of lower extremity, 797 
of upper extremity, 792 
muscles of abdomen, 449 
palmar arch, 658 
fascia, 493 
veins, 747 
parotid lymphatic glands, 782 
patellar bursa, 518 
pectoral fascia, 464 
perineal fascia, 1538 
petrosal nerve, 1073 
radial veins, 747 
superficial external pudic ar- 
tery, 704 
temporal artery, 614 
nerves, 1037 
veins, 727 
transverse fascia of leg, 537 
ulnar veins, 747 
veins of foot, 758 
of lower extremity, 758 
of upper extremity, 747 
Deiters, cells of, 1175 
nucleus of, 926, 1050 
process, 817 
Deltoid eminence, 179 
impression, 179 
muscle, 470 
relations of, 471 
tubercle, 168 
Demilunes of Heidenhain, 1218 
D6mours, membrane of, 1110 
Dendraxones, 821 
Dendrites of nerve-cells, 821 
Dental artery, inferior, 614 
posterior, 615 
band, 1205 
canal, 1202 
Dental canal, anterior, 107 
inferior, 124 
posterior, 106 
fibres, 1202 
follicle, 1206 
lamina, 1205 
nerves, anterior superior, 1033 
inferior, 1039 
middle superior, 1033 
posterior superior, 1032 
periosteum, 1204 
plexus, superior, 1033 
pulp, 1200 
sac, 1206 
tubuli, 1202 
Dentate convolution, 879 
gray matter of, 921 
fascia, 879, 898 
fissure, 871, 879 
ligament, 835 
Dentinal sheath of Neumann, 
1203 
tubuli, 1202 
Dentine, 1202 
development of, 1207 
papilla, 1205 
Depression, pterygoid, 125 
trigeminal, 88 
Depressions of bone, 34 
Depressor alse nasi muscle, 376- 
anguli oris muscle, 378 
relations of, 378 
labii inferioris muscle, 378 
relations of, 378 
Dermic coat of hair-follicle, 1188. 
Dermis, 1180 
Descemet, membrane of, 1110 
Descendens hypoglossi nerve,. 
1066 
Descending aorta, 665 
branch of superior cervical 
ganglion, 1074 
colon, 1309 
comma tract, 844 
cornu of lateral ventricle, 890 
mesocolon, 1258 
nerve tract, 959 
oblique muscle of abdomen, 
433 
palatine artery, 615 
ramus of ischium, 211 
of pubis, 213 
root of fifth nerve, 1026 
Descent of ovary, 1501 
of testicles, 1461 
surgical anatomy of, 1462 
Detrusor urina) muscle, 1437 
Development of alimentary ca- 
nal, 1236 
of alveoli of teeth, 1207 
of atlas, 59 
of axis, 59 
of brain, 857 
of carpal bones, 205 
of cement um, 1207 
of clavicle, 170 
of coccyx, 66 
of cranium, 102 
of dentine, 1207 
of enamel, 1206 
of ethmoid bone, 101 
of femur, 228 
of fibula, 238 
of foot, 253 
of frontal bone, 82 
of humerus, 182 
of hyoid bone, 154 
of inferior turbinated bone, 
120 
of lachrymal bone, 113 
of liver, 1243 INDEX 
1561 
Development of maxillary bone, 
inferior, 125 
of mesentery, 1237 
of metacarpal bones, 205 
of metatarsal bones, 253 
of organs, chronological table 
of, 1547 
of nasal bones, 105 
of nerve-cells, 823 
-fibres, 823 
of occipital bone, 75 
of omentum, 1238 
of os innominatum, 214 
of palate bone, 119 
of pancreas, 1244 
of parietal bone, 78 
of patella, 231 
of peritoneal cavity, 1242 
of peritoneum, 1234, 1242 
of permanent teeth, 1208 
of phalanges of foot, 254 
of hand, 206 
of radius, 192 
of ribs, 163 
of sacrum, 64 
of scapula, 175 
of sphenoid bone, 97 
of spleen, 1245 
of sternum, 158 
of superior maxillary bones, 
112 
of tarsal bones, 253 
of teeth, 1204 
of temporal bone, 91 
of tibia, 236 
of tongue, 1242 
of tonsils, 1243 
of ulna, 189 
of vertebra*, 58 
of viscera, 1234 
of vomer, 122 
Wormian, 103 
Diagonal sulcus, 868 
Diameter of pelvis, 217 
Diaphragm, 427 
actions of, 430 
crura of, 427 
lymphatics of, 810 
nerves of, 430 
openings of, 429 
aortic, 429 
oesophageal, 430 
for vena cava, 430 
of pelvis, 1231 
pillars of, 427 
serous membranes of, 430 
tendons of, central, 429 
Diaphragma sellae, 851, 882 
Diaphragmatic ganglion, 1084 
hernia, 427 
lymphatic, 810 
pleura, 1386 
portion of oesophagus, 1226 
Diaphysis, 34 
Diarthrosis, 265 
Diaxonic cells, 821 
Digastric branch of facial nerve, 
1048 
fossa, 86, 123, 136 
lobe of cerebellum, 931 
muscle, 393 
relations of, 394 
nerve, from facial, 1048 
Digestion, organs of, 1193 
Digital arteries, dorsal, 659 
of ulna, 664 
fossa, 223 
nerves of foot, 1015 
hand, 987 
Dilator naris anterior muscle, 376 
posterior muscle, 376 
Dilator t uba* muscle of Rudinger, 
1155 
Diploe, 34 
veins of, 733 
Diploic canals, 733 
veins, frontal, 734 
occipital, 734 
parietal external, 734 
temporal, anterior, 734 
posterior, 734 
Direct cerebellar tract, 843 
inguinal hernia, 1523 
pyramidal tract, 842 
Disk, interpubic, 296 
intervertebral, 270 
optic, 1121 
Dissection of axilla, 463 
of brain, 847 
of internal oblique muscle, 437 
of muscles of abdomen, 432 
of arm, 470 
of auricular region, 369 
of back, 410, 414, 415, 417 
of cranial region, 366 
of femoral region, anterior, 
512 
internal, 519 
posterior, 529 
of fibular region, 539 
of forearm, 478, 482 
of gluteal region, 522 
of hand, 491 
of iliac region, 508 
of infra-hyoid region, 391 
of intermaxillary region, 378 
of lingual region, 396 
of mandibular region, 377 
of orbital region, 372 
of palatal region, 403 
of palpebral region, 370 
of pectoral region, 463 
of pharyngeal region, 400 
of plantar region, 544, 545, 
546 
of pterygo-mandibular re- 
gion, 383 
of radial region, 484 
of scapular region, anterior, 
471 
posterior, 472 
of shoulder, 470 
of superficial cervical region 
386 
of supra-hyoid region, 393 
of tibio-fibular region, ante- 
rior, 532 
posterior, 534, 537 
of pancreas, 1348 
of perinjeum, 1535 
of popliteal space, 707 
of rectus abdominis muscle, 442 
of sole of foot, 542 
of spinal cord, 832 
of temporal muscle, 382 
of transversalis muscle, 441 
Diverticulum, Meckel's, 1290 
Dorsal artery of penis, 692 
auditory nuclei, 950 
digital arteries, 659 
veins, 745 
divisions of cervical nerves, 
968 
interosseous arteries, 659, 715 
nerves, 993 
of clitoris, 1013 
divisions of, anterior, 993 
posterior, 993 
of penis, 1013 
roots of, 993 
region, muscles of, 543 
root of eighth nerve, 1051 
Dorsal root of spinal nerves, 965 
ulnar vein, 745 
veins of penis, deep, 762 
superficial, 762 
vertebrae, 53 
bodies of, 53 
lamina of, 54 
peculiar, 55 
pedicles of, 54 
processes of, 54 
Dorsalis hallucis artery, 716 
indicis artery, 659 
linguae artery, 603 
nasi artery, 625 
pedis artery, 714 
branches of, 715 
peculiarities of, 715 
relations of, 714 
surface marking of, 715 
surgical anatomy of, 715 
pollicis arteries, 659 
scapulae artery, 651 
Dorsi-lumbar nerve, 996 
-spinal veins, 753 
Dorso-lateral cerebellar tract, 843: 
-median fissure, 838 
-ventral fibres of cord, 841 
Dorsum ephippii, 93, 152 
of penis, 1455 
of scapula, 172 
sellae, 93 
Douglas, fold of, semilunar, 439, 
444 
pouch, 1490 
Drumhead, 1155 
Duct or ducts, aberrant, of epi- 
didymis, 1472 
alveolar, 1378 
of Bartholin, 1217 
biliary, 1341 
of Cuvier, 561 
cystic, 1344 
ejaculatory, 1476 
galactophorus, 1507 
Gartner's, 1499 
hepatic, 1342 
interlobular, 1341 
of kidney, 1420 
lactiferous, 1507 
of liver, 1341 
lymphatic, right, 778 
mammillary, 1507 
nasal, 1142 
pancreatic, 1351 
parotid, 1215 
of Rivinus, 1217 
seminal, 1472 
Stenson's, 1215 
of submaxillary gland, 1216 
thoracic, 775 
thyroglossal, 1090, 1401 
Wharton's, 1216 
Ductless glands, 1401 
Ductus arteriosus, 579 -- 
communis choledochus, 1344 
endolymphaticus, 89, 1165 
venosus, fissure of, 1331 
fossa of, 1331 
Duodenal area of kidney, 1414 
folds, 1260 
inferior, 1261 
superior, 1261 
fossa*, 1260 
inferior, 1260 
superior, 1261 
glands, 1295 
impression of liver, 1329 
Duodeno-jejunal fossa, 1261 
-mesocolic ligaments, 1261 
-renal ligament, 1255 
Duodenum, 1282 1562 
INDEX 
Duodenum, arteries of, 1288 
ascending portion of, 1286 
descending portion of, 1285 
first portion of, 1284 
flexure of, superior, 1285 
fourth portion of, 1286 
horizontal portion of, 1285 
interior of, 1288 
lymphatics of, 1288 
muscular coat of, 1288 
nerves of, 1288 
peritoneal coat of, 1288 
pre-aortic portion of, 1285 
second portion of, 1285 
structure of, 1288 
submucous coat of, 1288 
superior portion of, 1284 
surgical anatomy of, 1325 
suspensory muscle of, 1286 
third portion of, 1285 
transverse portion of, 1285 
veins of, 1288 
Dura mater of brain, 847 
arteries of, 848 
lymphatics of, 849 
nerves of, 849 
processes of, 849 
structure of, 848 
veins of, 849 
sinuses of, 736 
of spinal cord, 832 
structure of, 834 
Duverney, gland of, 1482 
E 
Ear, 1144 
auditory meatus, external, 
1148 
auricle, 1144 
bones of, 1158 
cartilages of, 1146 
■cochlea, 1165 
-drum membrane, secondary, 
1152 
external, 1144 
auricle of, 1144 
lobule of, 1145 
internal, 1163 
labyrinth, 1163 
membranous, 1169 
osseous, 1164 
middle, 1150 
muscles of auricle, 1147 
of tympanum, 1157 
ossicula of, 1158 
pinna of, 1144 
semicircular canals of, 1165 
surgical anatomy of, 1176 
trumpet, 1153 
tympanum, 1150 
v. Ebner, glands of, 1091 
Efferent nerve tract. 959 
Egg tubes, 1502 
Eighth nerve, 1050 
origin of, 1050 
roots of, 1050 
surgical anatomy of, 1054 
Ejaculator seminis muscle, 457 
urinse muscle, 457 
Ejaculatory ducts, 1476 
Elastic cartilage, 260 
tissue, yellow, 261 
Elbow, bend of, surgical anatom v 
of, 653 
bone, 184 
bursa of, 311 
-joint, articulations of, 308 
surface form of, 312 
surgical anatomy of, 312 
Elbow, ligament of, anterior, 
309 
posterior, 309 
Eleventh nerve, 1063 
surgical anatomy of, 1063 
Ellipsoid of Krause, 1127 
Elliptical recess, 1164 
Eminence, articular, of temporal 
bone, 84 
of bone, 34 
canine, 106 
deltoid, 179 
frontal, 79 
ilio-pectineal, 210, 213 
of Jacobson, 1100 
nasal, 79 
olivary, 93 
parietal, 76 
Eminentia articularis, 84, 135 
collateralis, 890 
conclue, 1146 
fossa? triangularis, 1046 
teres, 945 
Emissary veins, 743 
surgical anatomy of, 743 
Emulgent vein, 766 
Enamel cells, 1206 
cuticle, 1204 
fibres, 1203 
jelly, 1206 
-organ of tooth, 1205 
prisms, 1203 
of teeth, 1203 
development of, 1206 
Enarthrosis, 266 
Encephalon, 857 
Encysted hernia, 1523 
End-bulb of Krause, 827 
Endocardium, 574 
Endo-gnathion, 111 
Endolymph, 1169 
Endoneurium, 825 
Endosteum, 36 
Endothelium, corneal, 1111 
Endothoracic fascia, 1385 
Ensiform appendix, 158 
surfaces of, 158 
cartilage, 155 
Eosinophiles, 56 
Epactal bones, 103 
Eparterial branch of bronchus, 
1377 
Epencephalon, 857 
Ependyma, 888 
Epicondyles, 181 
Epicondylic ridge, 179 
Epicteric bone, 103 
Epidermic coat of hair-follicle, 
1188 
Epididymis, 1469 
aberrant ducts of, 1472 
structure of, 1471 
Epidural space, 833, 847 
Epigastric arterv, deep, 696, 
1518 
peculiarities of, 696 
surgical anatomy of, 697 
internal, 696 
superficial, 704 
superior, 645 
glands, superior, 802 
plexus, 1083 
vein, deep, 759 
Epiglottis, 1365 
cartilage of, 1365 
cushion of, 1365 
surfaces of, 1365 
Epimysium, 361 
Epineurium, 825 
Epiotic portion of temporal bone, 
91 
Epiphysial cartilage, 36 
Epiphysis of bone, 34 
cerebri, 905 
Epithelium. See Various organs, 
germinal, of Waldeyer, 1501 
lens, 1130 
transitional, 1428 
Epitrochlea, 181 
Epitympanic recess, 87, 1150 
space, 87 
Epo-ophoron, 1499 
Erectile tissue of penis, 1457 
of vagina, 1485 
Erector clitoridis muscle, 461 
penis muscle, 458 
spime muscle, 417 
relations of, 420 
Ethmo-frontal suture, 130 
-sphenoidal, 130 
Ethmoid bone, 98 
articulations of, 102 
cribriform plate of, 99 
development of, 101 
horizontal lamina of, 99 
infundibulum of, 101 
lateral mass of, 100 
os planum of, 100 
perpendicular plate of, 
100 
unciform process of, 100 
Ethmoidal arteries, 623 
canals, 82, 100 
cells, 82, 100 
posterior, 145 
crest, 94 
foramina, 82 
anterior, 130, 141 
posterior, 130 
notch, 82 
process of inferior turbinated, 
120 
sinuses, 101 
spine, 93, 130 
Eustachian cushion, 1221 
tube, 1153 
canal for, 1154 
cartilaginous portion of, 
1154 
osseous portion of, 1154 
valve, 567 
in fcetus, 578 
Excretory apparatus of liver, 
1342 
Exo-gnathion, 111 
Expiration, muscles of, 432 
Expression, muscles of, 385 
Exsanguinated renal zone of 
Hyrtl, 679, 1423 
Extensor brevis digitorum mus- 
cle, 543 
pollicis muscle, 489 
carpi radialis brevior muscle, 
485 
bursa of, 486 
longior muscle, 485 
ulnaris muscle, 487 
coccygeus muscle, 422 
communis digitorum muscle, 
486 
relations of, 487 
indicis muscle, 490 
longus digitorum muscle, 533 
pollicis muscle, 489 
minimi digiti muscle, 487 
ossis metacarpi pollicis, 489 
primi internodii pollicis mus- 
cle, 489 
proprius hallucis muscle, 532 
relations of, 533 
secundi internodii pollicis mus- 
cle, 489 INDEX 
1563 
External abdominal ring, 436, 
1514 
acoustic canal, 1148 
angular process, 80, 140 
annular ligament, 542 
anterior thoracic nerve, 984 
arcuate ligament, 427, 449 
auditory canal, 1148 
meatus, 138, 1148 
bicipital ridge, 179 
calcaneal nerves, 1014 
calcanean artery, 718 
calcaneo-astragaloid ligament, 
352 
-scaphoid ligament, 353 
capsule of brain, 894 
carotid artery, 600 
foramen, 89 
circumflex artery of thigh, 705 
condyle of femur, 226 
crucial ligament, 337 
cutaneous nerve, 985, 1003 
ear, 1144 
epicondyle, 181 
geniculate body, 904, 912 
hiemorrhoidal veins, 760 
iliac artery, 694 
glands, 797 
vein, 759 
inguinal fossa, 1520 
hernia, 1520 
interchondral ligament, 290 
intercostal muscle, 425 
jugular vein, 728 
lateral ligament, 280, 310 
malleolus, 238 
ligament of, 1160 
mammary artery, 651 
maxillary artery, 604 
oblique line, 123 
muscle, 433 
aponeurosis of, 1513 
occipital crest, 72, 136 
protuberance, 71, 136 
orbital foramina, 95 
os, 1489 
palatine nerve, 1035 
palpebral arteries, 623 
parietal diploic vein, 734 
parieto-occipital sulcus, 867 
plantar artery, 720 
nerve, 1016 
popliteal nerve, 1016 
pterygoid muscle, 383 
nerve, 1037 
plate, 96 
pudic artery, deep, 704 
superficial, 704 
deep, 704 
saphenous gland, 795 
vein, 756 
semicircular canal, 1165 
semilunar fibrocartilage, 339 
spermatic fascia, 436, 1514 
sphincter ani muscle, 450 
supracondylar ridge, 179 
tarsal ligament, 370 
tuberosity of tibia, 233 
Extracranial lymphatics, 780 
Extrinsic muscles of tongue, 398 
Eye, 1103 
appendages of, 1137 
aqueous humor of, 1128 
choroid, 1111 
ciliary muscle, 1115 
conjunctiva, 1140 
cornea, 1108 
crystalline lens, 1130 
globe of, arteries of, 1132 
lymphatics of, 1133 
nerves of, 1134 
Eve, globe of, veins of, 1133 
iris, 1117 
lachrymal apparatus, 1141 
glands, 1141 
sac, 1142 
nasal duct, 1142 
pupil of, 1117 
refracting media of, 1128 
retina, 1120 
sclera, 1107 
surgical anatomy of, 1134 
-teeth, 1197 
tunics of, 1107 
uvea of, 1118 
vitreous body of, 1129 
Eyeball, coverings of, 375 
Eyebrow, 1137 
Eyelashes, 1138 
surgical anatomv of, 1143 
Eyelid, 1137 
Meibomian glands of, 1139 
orbital portion, 1137 
structure of, 1138 
surface form of, 1143 
surgical anatomy of, 1143 
tarsal portion, 1137 
Erythroblasts, 36 
F 
Face, arteries of, 604 
bones of, 104 
exterior of, veins of, 725 
fasciae of, 365 
lymphatics of, 779 
muscles of, 365 
surface form of, 385 
nerves of, 1044 
veins of, 726 
Facet, clavicular, 157 
costal, 169 
Facial artery, 604 
branches of, 605 
relations of, 605 
surgical anatomy of, 607 
transverse, 611 
bones, 104 
nerve, 1044 
branches of, 1046 
nucleus of, 925 
surgical anatomy of, 1049 
suture, transverse, 128 
vein, anterior, 726 
common, 726 
transverse, 727 
surgical anatomy of, 726 
Falciform crest, 89 
ligament, 293 
of liver, 1333 
process of fascia lata, 515 
Fallopian tube, 1497 
ampulla of, 1497 
artery of, 1498 
course pursued by, 1498 
fimbriae of, 1497 
infundibulum of, 1497 
isthmus of, 1497 
lymphatics of, 804, 1498 
nerve of, 1499 
structure of, 1498 
uterine portion of, 1497 
vein of, 1498 
False pelvis, 215 
ribs, 159 
vocal cords, 1370 
Falx cere belli, 850 
cerebri, 849 
inguinalis, 448 
Fascia or fascia*. 361 
of abdomen, deep, 433 
Fascia or fasciae, of abdomen, 
superficial, 433, 1511 
triangular, 1515 
of acromial region, 470 
anal, 454, 1546 
of arm, 474 
deep, 470 
superficial, 470 
axillary, 463, 646 
of back, deep, 411 
superficial, 411 
bicipital, 476, 746 
bucco-pharyngeal, 380, 388, 
401, 1222 
of Camper, 433 
cervical, deep, 387 
superficial, 386 
clavi-pectoral, 467 
of Colles, 456, 1515 
costo-coracoid, 467 
of cranium, 365 
cremasteric, 1464, 1516 
cribriform, 512, 1527 
deep, 364 
dentate, 879, 898 
endo-pelvica, 1544 
endothoracic, 1385 
of face, 365 
of femoral region, anterior, 
deep, 513 
superficial, 512 
of foot, 541 
of forearm, 478 
of hand, 491 
of hip, 522 
iliac, 508 
infraspinatus, 472 
infundibuliform, 446, 1464 
intercolumnar, 436, 1463, 1514 
intercostal, 424 
ischio-rectal, 454, 1546 
lata, 513, 1527 
falciform process of, 1528 
iliac portion, 514, 1528 
pubic portion, 514, 1528 
of leg, 532 
transverse, 537 
of lower extremity, 507 
masseteric, 381 
of neck, 385 
obturator, 1546 
of orbit, 374 
palmar, deep, 493 
palpebral, 1139 
parotid, 388, 1215 
parotideo-masseterica, 388 
pectoral, deep, 464 
pelvic, 1544 
of perinaeum in male, deep, 
458, 1538 
superficial, 455 
phrenico-pleural, 1386 
plantar, 542 
pre-tracheal, 388 
prevertebral, 388 
of quadratus lumborum, 449 
recto-vesical, 1546 
retro-renal, 1412 
salpingopharyngea of Troltsch 
1155 
of Scarpa, 433 
semilunar, 476 
of shoulder, deep, 470 
superficial, 470 
spermatic, 1463 
external, 436, 1514 
internal, 446 
middle, 440 
subscapular, 471 
superficial, 364 
of cranial region, 366 1564 
INDEX 
Fascia or fasciae, supraspinatus, 
472 
temporal, 381 
of thigh, 512 
of thoracic region, anterior, 
deep, 463 
superficial, 463 
of thorax, 424 
transversalis, 445, 1517 
triangular, 437 
of trunk, 410 
of upper extremity, 462 
Fascial canal, 1536 
Fasciculi, 261 
Fasciculus cuneatus, 941 
gracilis, 941 
clava of, 941 
longitudinal, inferior, 918 
superior, 918 
occipito-frontal, 918 
perpendicular, 918 
rectus, 918 
of Rolando, 941 
teres, 945 
of Turek, 842 
uncinate, 917 
Fasciola cinerea, 879 
Fauces, isthmus of, 1212 
pillars of, 1211 
Female bladder, 1446 
organs of generation, 1477 
perinseum, 1542 
urethra, 1446 
Femoral artery, 697 
anastomotica magna of, 707 
branches of, 704 
common, 699 
deep, 704 
peculiarities of, 701 
superficial, 700 
surface marking of, 701 
surgical anatomy of, 701 
canal, 509, 1531 
cutaneous nerves, 1011 
hernia, 1525 
complete, 1534 
coverings of, 1533 
descent of, 1533 
incomplete, 1533 
varieties of, 1533 
ligament, 515 
lymphatic glands, deep, 795 
region, anterior, fascia of, deep, 
513 
superficial, 512 
surgical anatomy of, 515 
muscles of, 512 
dissection of, 512 
surgical anatomy of, 518 
internal, muscles of, 519 
dissection of, 519 
surgical anatomy of, 522 
posterior, muscles of, 529 
dissection of, 529 
surgical anatomv of, 531 
ring, 437, 509, 1532 
sheath, 509, 1530 
spur, 227 
vein, 758 
Femur, 221 
articulations of, 228 
attachment of muscles to, 229 
condyles of, 225 
development of. 228 
lower extremity of, 225 
shaft of, 224 
borders of, 225 
linea aspera, 224 
surfaces of, 225 
spiral line of, 223 
structure of, 226 
Femur, surface form of, 229 
surgical anatomy of, 229 
trochlea of, 225 
tubercle of, 223 
tuberosities of, 226 
upper extremity of, 221 
head of, 221 
neck of, 222 
trochanters of, 223 
Fenestra ovalis, 1152 
rotunda, 1152, 1167 
Fenestrated membrane of Henle, 
585 
Ferrein, pyramids of, 1417 
Fibre-baskets, 1127 
Fibres of auricles of heart, 575 
of cerebellum, peduncular, 932 
projection, 932 
proper, 936 
of cerebrum, association, 916 
commissural, 916 
peduncular, 914 
projection, 914 
transverse, 916 
of cord, dorso-ventral, 841 
longitudinal, 841 
oblique, 841 
transverse, 841 
dental, 1202 
enamel, 1203 
inter-cerebral, of optic com- 
missure, 1021 
intercolumnar, 436 
of internal capsule of brain, 
892 
lens, 1130 
of medulla, arciform, 942 
arcuate, 942 
of pons Varolii, 923 
longitudinal, 923 
transverse, 923 
preanal, of levator ani, 453 
pr^-rectales, 454 
of Remak, 823 
of Sharpey, 37 
sustentacular, 1121 
of tegmentum, 908 
of ventricles of heart, 575 
Fibro-cartilage, 260 
circumferential, 261 
connecting, 261 
interarticular, 281, 298, 300 
triangular, 315 
intervertebral, 270 
semilunar, 337 
stratiform, 261 
-elastic coat of spleen, 1356 
-muscular coat of gall-bladder, 
1343 
Fibrous band of Baillarger, 920 
of Bechterew, 920 
coat of liver, 1337 
of pharynx, 1223 
of ureter, 1427 
membrane of trachea, 1379 
rings of heart, 574 
septum of tongue, 398 
sheaths of flexor tendons, 545 
tissue, white, 261 
Fibula, 237 
articulations of, 238 
attachment of muscles to, 239 
development of, 238 
lower extremity of, 238 
nutrient artery of, 718 
oblique line of, 237 
shaft of, 237 
borders of. 237 
surfaces of, 238 
styloid process of, 237 
surface form of, 239 
Fibula, surgical anatomy of, 239 
upper extremity of, 237 
Fibular artery, superior, 713 
region, muscles of, 539 
actions of, 540 
dissection of, 539 
surgical anatomy of, 541 
Fifth nerve, 1026 
nuclei of, 925 
root of, ascending, 948 
semilunar ganglion of, 1027 
surface marking of, 1041 
surgical anatomy of, 1041 
ventricle, 897 
Filiform papilla1 of tongue, 1090 
Fillet, decussation of, 949 
of gyrus fomicatus, 879, 918 
interolivary, 909, 949 
lateral, 885, 910 
lower, 910 
median, 910 
mesial, 910 
superior, 910 
upper, 910 
Filtrum ventriculi of Merkel, 
1368 
Fimbria. 898 
Fimbriae of Fallopian tube, 1497 
of ovary, 1499 
Fimbrio-dentate fissure, 898 
Finger, index, metacarpal bone 
of, 202 
ligaments of, 322 
superficial transverse, 494 
little, metacarpal bone of, 203 
middle, metacarpal bone of, 
202 
ring, metacarpal bone of, 203 
veins of, superficial, 745 
First nerve, 1019 
Fissura antitragohelicina, 1146 
prima, 881 
vestibuli, 1168 
Fissure or fissures, antero-lateral, 
838 
antero-median, 837 
antitragohelicina, 1146 
auricular, 90, 136 
of Bichat, 900 
of brain, 865 
calcarine, 870 
callosal, 879 
of cerebellum, 927, 930 
of cerebrum, longitudinal, 865- 
882 
choroid, 890, 900 
collateral, 871 
of cord, 837 
lateral 838 
dentate, 871, 879 
dorso-median, 838 
of ductus venosus, 1331 
fimbrio-dentate, 898 
of gall-bladder, 1331 
Glaserian, 84, 1152 
hippocampal, 871, 879 
of liver, 1331 
longitudinal. 1331 
transverse, 1332 
of lung, 1392 
mammary, prolongations of, 
1505 
orbital, 96 
petro-tympanic, 84, 1152 
portal, 1332 
posterior median, 838 
post-clival, 928 
-limbic, 871 
-nodular, 930 
-pyramidal, 930 
pre-clival, 928 INDEX 
1565 
Fissure or fissures, pre-pyra- 
midal, 930 
pterygoid, 96 
ptery go-maxillary, 139 
of Rolando, 867 
sphenoidal 96, 132 
spheno-maxillary, 115, 138 
of Santorini, 1146, 1148 
of spinal cord, 837 
of Sylvius, 866, 884 
of tragus, 1146 
umbilical, 1331 
ventro-median, 837 
Flat bones, 34 
Flechsig, fibrous systems of, 915 
Flexor accessorius muscle, 546 
brevis digitorum muscle, 544 
hallucis muscle, 546 
minimi digiti muscle, foot, 
547 
hand,498 
pollicis muscle, 497 
carpi radialis muscle, 479 
ulnaris muscle, 480 
longus digitorum muscle, 538 
hallucis muscle, 538 
pollicis muscle, 482 
ossis metacarpi pollicis mus- 
cle, 497 
profundus digitorum muscle, 
482 
sublimis digitorum muscle, 481 
tendons, fibrous sheaths of, 545 
Flexure of colon, hepatic, 1309 
sigmoid, 1311 
splenic, 1309 
of duodenum, superior, 1285 
of large intestine, hepatic, 1300 
sigmoid, 1300 
splenic, 1300 
Floating lobe of liver, 1336 
Floccular fossa, 89, 133 
Flocculus, 931 
peduncle of, 931 
Flood's ligament, 304 
Foetal circulation, 579 
lung, 1394 
Fold of Douglas, semilunar, 439, 
444 
duodenal, 1260 
hypogastric, 1519 
o vario-pelvic, 1500 
recto-vaginal, 1490 
of urachus, 1519 
utero-vesical, 1490 
of uterus, 1489 
Folia linguae, 1087 
Folium cacuminis, 929 
Follicle, dental, 1206 
simple, 1295, 1319 
Follicular lymph-sinus, 1306 
Fontana, spaces of, 1110 
Fontanelles, 102 
anterior, 78 
Foot, arteries of, 714 
bones of, 239 
bursae of, 543 
development of, 253 
fasciae of, 541 
ligaments of, 541 
muscles of, 541 
nerves of, 1015 
phalanges of, 252 
articulations of, 359 
sole of, dissection of, 542 
surface form of, 255, 360 
surgical anatomy of, 256, 360 
veins of, 758 
Foramen, 96 
caecum, 80, 130, 1087 
carotid, external, 89 
Foramen, carotid, internal, 88 
condyloid, anterior, 73, 133, 
136 
posterior, 73, 133, 136 
costo-transverse, 50 
dental, inferior, 124 
diaphragmatis sella;, 883 
ethmoidal, anterior, 130, 141 
posterior, 130, 141 
of Huschke, 92 
infraorbital, 106, 140 
jugular, 73, 133 
of Key and Retzius, 853 
lacerum anterius, 96, 132 
medium, 132 
posterius, 133 
of Langer, 464, 646, 791 
magnum, 72, 133 
of Majendie, 834, 853 
malar, 113 
mastoid, 85, 138 
mental, 123, 140 
of Monro, 889 
obturator, 214 
optic, 93, 131, 142 
ovale, 95, 132, 567 
in foetus, 578 
palatine, great, 116 
posterior, 135 
parietal, 76 
pterygo-palatine, 95 
quadratum of diaphragm, 430 
rotundum, 95, 132 
sacro-sciatic, great, 211, 294 
singulare, 89, 1169 
of Sommerring, 1121 
spheno-palatine, 119, 143 
spinal, 49, 132 
sternal, 157 
stylo-mastoid, 90, 135 
supratrochlear, 181 
supraorbital, 80, 140 
temporo-malar, 115 
thyroid, 214 
vertebral, 49 
vertebrarterial, 50 
Vesalii, 95, 132 
Foramina of diaphragm, 430 
ethmoidal, 82 
incisor, 110 
intervertebral, 49 
of Key and Retzius, 834 
malar, 113 
olfactory, 143 
orbital, external, 95 
sacral, anterior, 62 
posterior, 63 
of Scarpa, 110, 135, 1036 
of Stenson, 110 
Thebesii, 567, 568, 771 
Fore-gut, 1236 
Forearm, arteries of, 657 
bones of, 184 
fasciae of, 478 
interosseous veins of, 747 
lymphatics of, 788 
muscles of, 478 
dissection of, 478, 482 
nerves of, 984 
veins, 744 
Fore-brain, 857 
Forel, occipito-frontal fasciculus 
of, 918 
Form of bones, 33 
Formatio reticularis, 845, 948 
alba, 949 
grisea, 949 
Fornix, 895 
body of, 895 
of conjunctiva, 1140 
lyra of, 896 
Fornix, pillars of, anterior, 895 
posterior, 896 
vaginal, 1484 
Fossa or fossae of acetabulum,213 
of antihelix, 1144 
canine, 106, 140 
condyloid, anterior, 136 
posterior, 136 
coronoid, 181 
cranial, 143 
digastric, 86, 123, 136 
digital, 223 
duodenal, 1260 
duodeno-jejunal, 1261 
floccular, 89, 133 
glenoid, 84, 135 
of helix, 1145 
ileo-appendicular, 1263 
-caecal, 1263 
-colic, 1262 
iliac, 209 
incisive, 106, 123, 139 
incudis, 1153 
infraspinous, 172 
inguinal, 1248, 1520 
external, 1520 
internal, 1520 
middle, 1520 
intersigmoid, 1312 
ischio-rectal, 1536 
jugular, 91 
lachrymal, 81 
of Landzert, 1262 
longitudinal, of liver, 1331 
mandibular, 84 
mastoid, 86 
mesocolic, 1261 
myrtiform, 106 
nasal, 142, 1098 
navicularis of urethra, 1444 
of vulva, 1478 
occipital, 133 
olecranon, 181 
orbital, 143 
ovalis, 567 
palatine, anterior, 110, 133 
paraduodenal, 1262 
pate Haris, 1129 
pericaecal, 1262 
pituitary, 93 
pterygoid, 96, 115 
radial, 181 
retro-caecal, 1263 
-colic, 1263 
-duodenal, 1262 
-peritoneal, 1260 
rhomboid, inferior, 840 
of Rosenmuller, 1221 
of Scapha, 1145 
scaphoid, 97, 135, 1145 
sigmoid, 86 
of skull, anterior, 130 
infratemporal, 138 
middle, 130 
orbital, 140 
pterygo-palatine, 139 
posterior, 132 
spheno-maxillary, 139 
temporal, 137 
zygomatic, 138 
spheno-maxillary, 115 
sublingual, 123 
submaxillary, 123 
subscapulus, 171 
supra-tonsillar, 1213 
supraspinous, 172 
temporal, 76 
of Treitz, 1260 
trochanteric, 223 
trochlear, 82 
umbilical, 1331 1566 
INDEX 
Fossula inferior, 1168 
superior, 1168 
Fourchette, 1478 
Fourth nerve, 1025 
ventricle, 942 
lining membrane of, 945 
roof of, 943 
triangles of, 945 
wall of, anterior, 944 
posterior, 943 
Fovea centralis retinae, 1121, 
1128 
hemielliptica, 1164 
hemispherica, 1164 
inguinalis lateralis, 1520 
mesialis, 1520 
oblonga, 1364 
superior, 945 
supra-vesicularis, 1520 
triangularis, 1364 
Foveolae, Howship's, 38 
Fraenulum of cerebellum, 928 
of ileo-caecal valve, 1308 
Fraenum of clitoris, 1479 
labii superioris et inferioris, 
1194 
linguae, 1087 
of penis, 1455 
Frontal air sinus, 82 
artery, 611 
from anterior cerebral, ante- 
rior internal, 627 
inferior internal, 627 
middle internal, 627 
posterior internal, 627 
from middle cerebral, as- 
cending, 628 
inferior external, 628 
from ophthalmic, 625 
bone, 79 
horizontal portion of, 81 
articulations of, 83 
attachment of muscles 
to, 83 
border of, 82 
development of, 82 
structure of, 82 
orbital portion of, 81 
articulations of, 83 
attachment of muscles 
to, 83 
border of, 82 
development of, 82 
structure of, 82 
vertical portion, 79 
border of, 81 
. structure of, 81 
convolutions, ascending, 872 
inferior, 873 
middle, 873 
superior, 873 
crest, 80, 130 
diploic vein, 734 
eminence, 79 
horn of lateral ventricle, 889 
lobe, 872, 884 
nerve, 1030 
operculum, 866, 874 
process of malar, 114 
spine, 80 
sulci, 868, 873 
suture, 79, 127 
vein, 725 
Frontalis muscle, 368 
Fronto-parietal suture, 127 
-malar suture, 128 
-sphenoidal suture, 128 
Fundamental plexus, 1111 
Fundiform ligament of Retzius, 
541 
Fundus glands, 1277 
Fundus of internal auditory 
meatus, 1168 
tympani, 1151 
of uterus, 1487 
Fungiform papillae of tongue, 
1090 
Funicular process, hernia of, 
1523 
Funiculus, cuneate, 941 
gracilis, 941 
of Rolando, 941 
slender, 941 
teres, 945 
wedge-shaped, 941 
Furcula, 1242 
Furrow, interarticular, 565 
sternal, 165 
Fusiform muscles, 362 
G 
Galactophorus duct, 1507 
Galen, testes muliebres of, 1499 
veins of, 735, 771 
Gall-bladder, 1342 
arteries of, 1346 
body of, 1343 
fibro-muscular coat of, 1343 
fissure for, 1331 
fundus of, 1343 
lymphatics of, 1346 
mucous coat of, 1343 
neck of, 1343 
nerves of, 1346 
notch of, 1331 
relations of, 1343 
serous coat of, 1343 
structure of, 1343 
surgical anatomy of, 1347 
veins of, 1346 
Ganglia of nerves, 831 
semilunar, of abdomen, 1084 
of spinal nerves, 966 
Gangliated cord, 1071 
cervical portion of, 1071 
lumbar portion of, 1079 
pelvic portion of, 1080 
sacral portion of, 1080 
thoracic portion of, 1078 
Ganglion of Andersch, 1056 
Arnold's, 1039 
of Bochdalek, 1033 
cardiac, of Wrisberg, 1081 
carotid, 1073 
cephalic, 1031 
of cerebellum, 937 
cervical, inferior, 1077 
middle, 1076 
superior, 1072 
ciliary, 1031 
long root of, 1030 
of Corti, 1053 
diaphragmatic, 1084 
of facial nerve, 1045 
of fifth nerve, 1031 
Gasserian, 1027 
geniculate, 1034, 1045 
of glosso-pharyngeal, 1056 
impar, 1068 
inferior, 1056 
interpeduncular, 910 
jugular, 1056 
lenticular, 1031 
lumbar, 1080 
Meckel's, 1034 
mesenteric, 1085 
ophthalmic, 1031 
otic, 1039 
petrous, 1056 
pharyngeal, 1073 
Ganglion, phrenic, 10S4 
of pneumogastric, 1059 
of portio dura, 1045 
radicis cochlearis, 950 
of Ribes, 1067 
semilunar, of abdomen, 1084 
of fifth nerve, 1027 
spheno-palatine, 1034 
of spinal nerves, 966 
submaxillary, 1040 
superior, 1056 
of sympathetic nerves, 1071 
thoracic, 1078 
thyroid, 1076 
of Valentin, 1033 
vestibular, 1053 
Ganglionar gray matter, 922 
Ganglionic arteries, postero- 
lateral, 640 
postero-median, 640 
branch of nasal nerve, 1030 
vessels of brain, central, 630 
Gartner's duct, 1499 
Gasserian ganglion, 1027 
branches of, 1027 
Gastric area of kidney, 1414 
artery, 671, 674 
glands, 800, 1277 
true, 1277 
impression, 1333 
nerves, 1061 
plexus, 1085 
surface of liver, 1329 
of spleen, 1354 
veins, 768 
Gastro-colic omentum, 1256 
-duodenal plexus, 1085 
-duodenalis artery, 673 
-epiploic plexus, 1085 
left, 1085 
vein, 768 
-epiploica dextra artery, 673 
sinistra artery, 674 
-hepatic omentum, 1254 
-splenic ligament, 1256 
omentum, 1256 
Gastrocnemius muscle, 534 
bursa of, 534 
Gemellus muscle, inferior, 527 
superior, 526 
Generation, organs of, develop- 
ment of, 1547 
female, 1477 
male, 1447 
Genial gland, 782 
tubercles, 123 
Geniculate body, external, 904, 
912 
internal, 904, 912 
ganglion, 1034, 1045 
Genio-glossus muscle, 396 
-hyo-glossus muscle, 396 
-hyoid muscle, 395 
Genito-crural nerve, 1000 
crural branch, 1000 
genital branch, 1000 
Germ of corpus callcsum, 886 
Gerlach, valve of, 1303 
Germinal epithelium of Wal- 
deyer, 1501 
Giacomioni. band of, 879 
Gianuzzi, crescents of, 1218 
Gimbernat's ligament, 437, 1515 
Gingival branches of dental 
nerves, 1032 
Ginglymus, 265 
Giraldes, organ of, 1473 
Girdle, pelvic, 207 
shoulder, 207 
Glabella of frontal bone, 80, 139 
Gladiolus, 157 INDEX 
1567 
Gladiolus, borders of, 157 
surfaces of, 157 
Glands, absorbent, 774 
agminated, 1296 
apical, 1091 
arytenoid, 1375 
of Bartholin, 1482 
of biliary ducts, 1342 
of Bowman, 1101 
Brunner's, 1295 
buccal, 1195 
cardiac, 1278 
carotid, 1409 
ceruminous, 1149 
ciliary, 1190 
circumanal, 1190 
coccygeal, 1410 
conglobate, 774 
Cowper's, 1453 
ductless, 1401 
duodenal, 1295 
of Duverney, 1482 
epiglottis, 1374 
fundus, 1277 
gastric, 1277 
intestinal, 1295, 1319 
labial, 1195 
lachrymal, 1141 
of larynx, 1374 
lenticular, of stomach, 1277 
of Lieberkuhn, 1295, 1319 
lingual, 1091 
of LittrS, 1444 
Luschka's, 1410 
lymphatic, 774 
mammary, 1503 
lymphatics of, 812 
Meibomian, 1139 
molar, 1195 
of Moll, 1138 
of Montgomery, 1504 
mucilaginous, 262 
mucous, 1218 
of Nuhn and Blandin, 1091 
odoriferse, 1454 
oesophageal, 1210 
oxyntic, 1277 
of Pacchioni, 737, 854 
palatal, 1211 
parotid, 1214 
peptic, 1277 
Peyer's, 1296 
pharyngeal, 1224 
pineal, 905 
peduncles of, 895 
prostate, 1447 
lymphatic vessels of, 803 
pyloric, 1277 
of Rosenmuller, accessory, 
1141 
salivary, 1214 
sebaceous, 1138, 1191 
solitary, 1295, 1320 
sublingual, 1217 
submaxillary, 1216 
subparotid, 1215 
suburethral, 1482 
sudoriferous, 1190 
suprarenal, 1428 
sweat, 1190 
tarsal, 1139 
thymus, 1407 
thyroid, 1401 
arteries of, 602 
lymphatic vessels of, 782 
veins of, 731 
of tongue, 1091 
tracheal, 1380 
of Tyson, 1454 
of v. Ebner, 1091 
vul vo-vaginal, 1482 
Glandulae Pacchioni, 737, 854 
Tysonii odoriferae, 1454 
Glans clitoridis, 1480 
penis, 1454 
Glaserian fissure, 84, 1152 
Gleno-humeral ligament, 305 
Glenoid cavity, 175 
fossa, 84, 135 
ligament, 175 
of Cruveilhier, 359 
tuberosity, 175 
Glisson, capsule of, 770, 1256, 
1337 
Globus of epididymis major, 
1469 
minor, 1469 
Glosso-epiglottic ligament, 1365 
-epiglottidean folds, 1366 
-pharyngeal nerve, 1054 
nuclei of, 950 
surgical anatomy of, 1057 
Glottis, chink of, 1369 
false, 1369 
respiratoria, 1369 
true, 1369 
vocalis, 1369 
Gluteal artery, 694 
inferior, 693 
cutaneous nerve, 1011 
glands, 797 
line, anterior, 207 
inferior, 208 
posterior, 207 
nerve, inferior, 1011 
superior, 1010 
region, Ivmphatic vessels of, 
801 ' 
muscles <*f, 522 
dissection of, 522 
surgical anatomv of, 528 
ridge, 224 
veins, 761 
Gluteo-femoral bursa, 331 
Gluteus maximus muscle, 522 
medius muscle, 523 
minimus muscle, 523 
Golgi, cells of, 821 
organ of, 829 
Goll, tract of, 839, 843 
Gomphosis, 264 
Gonion, 124 
Graafian vesicles, 1502 
membrana granulosa of, 
1502 
ovicapsule of, 1502 
Gracilis muscle, 519 
Grande lobe limbique, 878 
Grandy's corpuscles, 827 
Granular sheath of Tomes, 1202 
Gray commissure of brain, 903 
of cord, 839 
anterior, 839 
posterior, 839 
matter, central, 922 
of cerebellum, 936 
of cerebrum, 918 
of cortex, 918 
of ganglia, 922 
of medulla, 945 
of pons, 924 
ventricular, 922 
nerve-fibres, 823 
substance of cord, 845 
anterior horn, 845 
dorsal horn, 845 
lateral horn, 845 
nerve-cells of, 845 
-fibres of, 845 
posterior horn, 845 
ventral horn, 845 
Great auricular nerve, 972 
Great cardiac nerve, 1077 
plexus, 1081 
vein, 770 
deep petrosal nerve, 1034 
occipital nerve, 969 
omentum, 1256 
sacro-sciatic foramen, 294 
ligament, 292 
sciatic nerve, 1013 
sinus of aorta, 589 
superficial petrosal nerve, 1034 
Greater alar cartilage, 1097 
wings of sphenoid, 95 
Grooves, auriculo-ventricular, of 
heart, 565 
basilar, 75 
bicipital, 179 
carotid, 93 
cavernous, 93 
of cord, 837 
infraorbital, 107, 141 
interventricular, 568 
of heart, 565 
intervertebral, 49 
lachrymal, 107, 109, 141, 143 
musculo-spiral, 179 
mylo-hyoidean, 124 
naso-palatine, 121 
obturator, 211, 213 
occipital, 86 
optic, 93, 130, 131 
peroneal, 245 
popliteal, 226 
pterygopalatine, 116 
sacral, 63 
of spinal cord, 837 
subclavian, 169 
subcostal, 162 
ulnar, 182 
vertebral, 155 
Gubemaculum testis, 1461 
Gudden's commissure, 912, 1021 
Guerin, valve of, 1444 
Gulf of internal jugular vein, 729 
Gullet, 1225 
Gums, 1195 
surgical anatomy of, 1224 
Gustatorv cells, 1091 
hair, 1091 
nerve, 1038 
branches of, 1038 
path, 1057 
pore, 1090 
Gyri of brain, 865 
brevis insulae, 878 
Gyrus, angular, 876 
annectant, deep, 867 
cinguli, 879 
fornicatus, fillet of, 879, 918 
lingual, 877 
longus insulae, 870 
marginal, 875 
occipito-temporal, 877 
post-central, 876 
praecentral, 872 
rectus, 874 
subcallosus, 882 
supra-callosus, 88 
H 
Habenula, 904 
commissure of, 904 
trigone of, 904 
I hemorrhoidal artery, inferior, 
690 
middle, 687 
superior, 678 
gland, middle, 799 
nerve, inferior, 1011 1568 
INDEX 
Hemorrhoidal plexus, inferior, 
1086 
superior, 1085 
veins, external, 760 
inferior, 760, 1011 
middle, 760 
superior, 768 
surgical anatomv of, 761 
Hair, 1187 
bloodvessels of, 1189 
-bulb, 1187 
coats of, dermic, 1188 
of, epidermic, 1188 
cortical substance of, 1189 
-follicle, 1187 
gustatory, 1091 
nerves of, 1189 
olfactory, 1101 
-papilla, 1187 
root of, 1187 
shaft of, 1189 
stem of, 1189 
-streams, 1187 
-whirlpools, 1187 
Haller, rete testis of, 1471 
Hamstring muscles, 529 
Hamular process of lachrymal, 
113 
of sphenoid, 96 
Hamulus, 1168 
Hand, arteries of, 660 
bones of, 193 
development of, 205 
bursa of, 492 
fasciae of, 491 
ligaments of, 319 
muscles of, 491 
dissection of, 491 
nerves of, from median, 987 
from radial, 991 
from ulnar, 989 
phalanges of, 204 
veins of, 745 
Hard palate, 1210 
Harmonia, 264 
Hasner, valve of, 1142 
Haustra coli, 1317 
Haversian canal, 38 
Head, arteries of, 595 
exterior of, veins of, 725 
lymphatic glands of, 780 
muscles of, surface form of, 
385 
veins of, 724 
Heart, 562 
arteries of, 577 
auricles of, fibres of, 575 
left, 568 
sinus of, 568 
right, 565 
cavities of, capacity of, 564 
circular fibres of, 575 
component parts of, 565 
■endocardium, 574 
fat upon, 564 
fibrous rings of, 574 
grooves of, auriculo-ventricu- 
lar, 565 
interventricular, 565 
infundibulum of, 569 
lymphatics of, 577 
muscular fibres of, 575 
myocardium, 574 
nerves of, 577 
position of, 562 
size of, 564 
spiral fibres of, 575 
structure of, 574 
muscular, 575 
surface form of, 577 
surgical anatomy of, 578 
Heart, veins of, 577 
ventricle of, fibres of, 575 
right, 569 
ventricular portion of, 568 
vortex of, 575 
weight of, 564 
Heel bone, 242 
Heidenhain, demilunes of, 1218 
Helicine arteries, 1458 
Helicis major muscle, 1147 
minor muscle, 1147 
Helicotrema of cochlea, 1167 
Helix, 1144 
crus of, 1145 
fossa of, 1145 
muscles of, 1147 
spine of, 1146 
Helmholtz, ligaments of, 1160 
Helwig, tract of, triangular, 843 
951 
Hemispheres of brain, surface of, 
under, 881 
of cerebellum, 885, 926 
of cerebrum, 864 
constituent parts of, 864 
general considerations of, 
864 
surfaces of, 865 
external, lobes on, 869 
mesial, fissures of, 869 
sulci of, 869 
outer, fissures of, 865 
sulci of, 865 
tentorial, fissures and 
sulci of, 869 
Henle, fenestrated membrane of, 
585 
ligament of, 43 S* 442 
loop of, 1419 
spine of, 88 
Hensen, canalis reuniens of, 1170 
cells of, 1175 
node, 857 
stripe, 1175 
Hepatic area of kidneys, 1414 
artery, 672 
cells,'1338 
ducts, 1342 
flexure of colon, 1309 
of large intestine, 1300 
glands, 801 
plexus, 1085 
veins, 767 
Hepato-colic ligament, 1255 
-duodenal ligament, 1255 
-gastric ligament, 1254 
Herbst, corpuscles of, 829 
Hernia, congenital, 1523 
diaphragmatic, 427 
encysted, 1523 
femoral, 1525 
of funiculaa process, 1523 
infantile, 1523 
inguinal, 1520 
direct, 1523 
external, 1520 
oblique, 1517. 1520 
scrotal, 1521 
surgical anatomy of. 1511 
Hesselbach, ligament of, 438, 
442, 1517 
triangle, 1520 
Hey, ligament of, 515 
Hiatus Fallopii, 88 
sacralis, 62 
semilunar, 747, 1099 
tendineus, 521 
Highmore, antrum of, 108 
Hilton, compressor sacculi laryn- 
gis muscle of, 1373 
white line of, 1319 
Hilum of kidney, 1415 
of ovary, 1500 
of spleen, 1-354 
Hind-brain, 922 
-gut, 1236 
Hinge-joint, 265 
Hip, articulations of, 325 
bursa of, 330 
fasciae of, 522 
ligaments of, 326 
muscles of, 522 
surface form of, 333 
surgical anatomy of, 333 
Hippocampal convolution, 879 
fissure, 871, 879 
Hippocampus major, 889, 897 
gray matter of, 921 
His, sulcus terminalis of, 566 
Histology of arteries, 584 
of capillaries, 584 
Hook bone, 199 
Horizontal cells of Cajal, 1125 
lamina of ethmoid, 99 
plate of palate bone, 116 
semicircular canal, 1165 
Homer's muscle, 371 
Horny layer of skin, 1181 
Horseshoe kidney, 1424 
Houston's valves, 1318 
Howship's lacuna?, 38 
Huguier, canal of, 84, 1047 
Humeral region, anterior, mus- 
cles of, 474 
posterior muscles of, 477 
Humerus, 177 
articulations of, 183 
attachment of muscles to, 
183 
capitellum of, 181 
development of, 182 
lower extremity of, 181 
nutrient canal of, 180 
shaft of, 179 
structure of, 182 
surface form of, 183 
surgical anatomy of, 183 
trochlea of, 181 
tuberosities of, 179 
upper extremity of, 177 
Humors of eye, 1128 
Hunter's canal, 521, 698 
Huschke, foramen of, 92 
Hyaline cartilage, 259 
Hyaloid canal of eye, 1129 
membrane of eye, 1129 
Hydatids of Morgagni, 1469 
non-pedunculated, 1469 
pedunculated, 1469 
Hymen, 1481 
imperforate, 1481 
Hyo-epiglottic ligament, 1365 
-glossus muscle, 397 
-thyroid membrane, 1366 
Hyoid artery of lingual, 603 
of superior thyroid, 602 
bone, 153 
attachment of muscles to, 
154 
basi-hyal of, 153 
body of, 153 
borders of, 154 
surfaces of, 153 
cornua of, greater, 154 
lesser, 154 
development of, 154 
region, infra-, muscles of, 
391 
supra-, muscles of, 393 
surface form of, 154 
surgical anatomy of, 154 
tubercle of, 153 INDEX 
1569 
Hyparterial branch of bronchus, 
1377 
Hypochondriac region, 1233 
Hypogastric artery, 683 
in foetus, 684 
fold, 1519 
nerve, 999 
plexus, 1080, 1085 
region, 1233 
vein, 760 
Hypoglossal nerve, 1064 
branches of, 1065, 1066 
surgical anatomy of, 1066 
nucleus, 949 
Hyrtl, exsanguinated renal zone 
of, 679, 1423 
I 
Ileo-appendicular fold, 1263 
fossa, 1263 
-ctecal fossa, 1263 
inferior, 1263 
superior, 1262 
valve, 1308 
fraenulum of, 1308 
-colic artery, 675 
fold, 1262 
fossa, 1262 
Ileum, 1289 
Iliac arteries, circumflex, deep, 
697 
superficial, 704 
common, 681 
branches of, 682 
compression of, 683 
peculiarities of, 682 
surface marking of, 682 
surgical anatomy of, 682 
external, 694 
branches of, 696 
relations of, 694 
surface marking of, 682, 
695 
surgical anatomy of, 695 
internal, 683 
branches of, 686 
peculiarities of, 685 
relations of, 683 
surface form of, 694 
surgical anatomv of, 685, 
694 
bursa, subtendinous, 331 
fascia, 508 
fossa, 209 
furrow, 220 
glands, 797 
common, 799 
external, 797 
internal, 799 
nerve, 999 
portion of fascia lata, 1528 
region, muscles of, 508 
surgical anatomy of, 511 
vein, circumflex, deep, 759 
common, 764 
peculiarities of, 764 
external, 759 
internal, 760 
Iliacus muscle, 510 
relations of, 511 
Ilio-capsularis muscle, 511 
-coccygeus muscle, 454 
-costalis muscle, 419 
-femoral ligament, 328 
-hypogastric nerve, 999 
-inguinal nerve, 999 
-lumbar artery, 693 
ligament, 291 
veins, 764 
llio-pectineal bursa, 330 
eminence, 210, 213 
ligament, 508 
line, 209 
-pelvic glands, 797 
-sciatic notch, 210 
-tibial band, 234, 514 
-trochanteric ligament, 329 
Ilium, 207 
borders of, 210 
crest of, 210 
dorsum of, 207 
processes of, 210 
spine of, 210 
surfaces of, 207, 208 
venter of, 209 
Impar ganglion, 1068 
Imperforate hymen, 1481 
Impression, deltoid, 179 
gastric, 1333 
Incisive fossa, 106, 123, 139 
Incisor canal, 110 
crest, 111 
foramina, 110 
nerve, 1039 
teeth, 1196 
Incisura cardiaca, 1392 
inter-arytsenoidea, 1368 
marsupialis, 926 
pancreatis, 1348 
semilunaris, 926 
Incremental lines of dentine, 
1203 
Incus, 1159 
body of, 1159 
ligaments of, 1161 
processes of, 1159 
Infantile hernia, 1523 
Inferior acromio-clavicular liga- 
ment, 299 
alveolar artery, 614 
branch of superior cervical 
ganglion, 1074 
calcaneo-scaphoid ligament, 
354 
surgical anatomy of, 354 
cardiac nerve, 1077 
carotid triangle, 616 
central nucleus, 949 
cerebral veins, 735 
cervical ganglion, 1077 
constrictor muscle, 400 
relations of, 401 
coronary artery of lip, 607 
dental artery, 614 
canal, 124 
foramen, 124 
nerve, 1039 
ethmoidal turbinate bone, 101 
external frontal artery, 628 
frontal convolution, 873 
gemellus muscle, 527 
gluteal artery, 693 
line, 208 
nerve, 1011 
haemorrhoidal artery, 690 
nerve, 1011 
plexus, 1086 
veins, 760 
internal frontal arteries, 627 
labial artery, 607 
lachrymal gland, 1141 
laryngeal artery, 641 
veins, 751 
lateral angle, 63 
lingualis muscle, 399 
longitudinal fasciculus, 918 
sinus, 738 
maxilla bone, 122 
horizontal portion of, 122 
surfaces of, 122 
Inferior maxillary bone, articula- 
tions of, 125 
attachment of muscles to, 
125 
development of, 125 
horizontal portion of, bor- 
ders of, 124 
perpendicular portion of, 
124 
borders of, 124 
processes of, 125 
surfaces of, 124 
nerve, 1036 
meatus of nose, 145 
medullary velum, 943 
mesenteric artery, 677 
plexus, 1085 
vein, 768 
nuchal line, 72 
obliquus oculi muscle, 374 
occipital convolution, 877 
fossae, 133 
sulcus, 877 
ophthalmic vein, 741 
orbito-palpebral sulcus, 1137 
palatine artery, 606 
pancreatico-duodenal artery, 
673 
parietal convolution, 876 
petrosal sinus, 742 
phrenic arteries, 680 
veins, 767 
post-central sulcus, 875 
profunda artery, 656 
pubic ligament, 296 
pudendal nerve, 1011 
pyloric artery, 673 
radio-ulnar articulation, 315 
ramus of ischium, 212 
of pubis, 213 
rectus oculi muscle, 373 
renal artery, 1423 
rhomboid fossa, 840 
sacro-sciatic foramen, 294 
semilunar lobe of cerebellum, 
931 
stephanion, 76 
superficial cerebellar veins, 736 
tarsal arch, 623 
temporal convolution, 877 
sulcus, 870 
thyroid artery, 641 
veins, 751 
transverse ligament, 302 
triangle of fourth ventricle, 945 
turbinated bone, 119 
articulations of, 120 
borders of, 120 
development of, 120 
processes of, 120 
surfaces of, 120 
crest, 107, 117 
vena cava, 764 
vermiform process of cerebel- 
lum, 929 
vesical artery, 686 
plexus, 762 
vocal cords, 1370 
Infraclavicular plexus, 792 
Infracostales muscle, 425 
Infraglenoid margin of tibia, 234 
tubercle, 174 
Infrahyoid artery, 602 
region, muscles of, 391 
Infralaryngeal glands, 787 
Inframandibular nerve, 1049 
Inframaxillary glands, 782 
nerve, 1049 
Infraorbital artery, 615 
canal, 107, 140 
foramen, 106, 140 1570 
J^DEX 
Infraorbital groove, 107, 141 
nerves, plexus of, 1049 
Infrapatellar bursa, 340 
Infraspinatus bursa, 315 
muscle, 472 
bursa of, 473 
Infraspinous fascia, 472 
fossa, 172 
Infrasternal depression, 165 
Infratemporal crest, 95 
fossa, 138 
Infratrochlear nerve, 1031 
Infundibula of kidney, 1415 
Infundibular artery, 590 
Infundibuliform fascia, 446, 1464 
Infundibulo-pelvic ligament, 1490 
Infundibulum of brain, 882 
of ethmoid, 101 
of Fallopian tube, 1497 
of heart, 569 
Ingrassias, processes of, 96 
Inguinal canal, 448, 1517 
fossa, 1248 
external, 1520 
internal, 1520 
middle, 1520 
hernia, 1520 
direct, 1523 
incomplete, 1524 
oblique, 1517, 1520 
lymphatic gland, deep, 795 
superficial, 793 
surgical anatomy of, 
794 
region, 1233 
Inion, 71 
Inlet of pelvis, 217 
Innominate artery, 593 
branches of, 594 
peculiarities of, 594 
relations of, 593 
surgical anatomy of, 594 
bone, 207 
vein, 750 
left, 750 
peculiarities of, 750 
right, 750 
Inosculation of arteries, 583 
Insertion of muscles, 363 
Inspiration, muscles of, 432 
Insula, 867, 878 
opercula of, 878 
Integument of scrotum, 1463 
Inter-alveolar cell islets, 1352 
Interarticular chondro-sternal 
ligament, 288 
fibro-cartilage, 281, 298, 300 
triangular, 315 
furrow, 565 
ligament, 284, 329 
septum, 565 
sterno-costal ligament, 288 
Inter-brain, 901 
Intercarotid body, 600 
Intercavernous sinus, 742 
Intercerebral fibres of optic com- 
missure, 1021 
Intercellular biliarv passages, 
1341 
Interchondral articulations, 289 
ligament, external, 290 
internal, 290 
Interclavicular ligament, 298 
Intercolumnar fascia, 436, 1463, 
1514 
fibres, 436 
Intercondyloid notch, 225 
Intercostal arteries, 667 
anterior. 644 
collateral. 668 
superior, 645 
Intercostal arteries, surgical ana- 
tomy of, 668 
fascia, 424 
glands, 810 
muscles, 425 
external, 425 
relations of, 425 
internal, 425 
relations of, 425 
nerves, 993 
abdominal, 996 
first, 995 
pectoral, 995 
surgical anatomy of, 996 
space, 155, 160 
veins, 752 
anterior, 752 
posterior, 752 
superior, left, 752 
right, 752 
Intercosto-humeral nerve, 995 
Interglobular spaces of Czermak, 
1202 
Interlobar arteries, 1423 
biliary plexus, 1338 
ducts, 1341 
Inter-maxillary bone, 110 
region, muscles of, 378 
suture, 139 
Intermediate crusta nerve path, 
960 
glands, 791 
zone of kidney, 1416 
Internal abdominal ring, 446, 
1518 
angular process, 80, 140 
annular ligament, 542 
anterior thoracic nerve, 984 
arcuate ligament, 427 
auditory artery, 639 
meatus, 133 
bicipital ridge, 179 
branches of superior cervical 
ganglion, 1076 
calcaneal nerve, 1015 
calcanean artery, 719 
calcaneo-astragaloid ligament, 
352 
-cuboid ligament, 353 
-scaphoid ligament, 354 
capsule of brain, fibres of, 892 
carotid artery, 619 
foramen, 88 
plexus, 1073 
circumflex artery of thigh, 705 
condyle of femur, 226 
crucial ligament, 337 
cutaneous nerve, 986, 1004 
ear, 1163 
epicondyle, 181 
epigastric artery, 696 
femoral region, muscles of, 519 
geniculate body, 904, 912 
iliac artery, 683 
glands, 799 
vein, 760 
inguinal hernia, 1520 
interchondral ligament, 290 
intercostal muscle, 425 
jugular glands, 786 
vein, 729 
bulb of, 729 
lateral ligament, 280, 310 
malleolar artery, 719 
malleolus, 235 
mammarv arterv, 643 
vein, 750 
maxillary artery. 612 
lymphatic glands, 782 
vein, 727 
oblique line, 123 
Internal oblique muscles, 437, 
1516 
occipital crest, 74, 113 
protuberance, 73 
orbital arteries, 627 
convolution, 873 
os, 1488 
palpebral arteries, 623 
parieto-occipital sulcus, 867, 
870 
plantar artery, 719 
nerve, 1015 
popliteal nerve, 1014 
pterygoid muscle, 383 
relations of, 384 
nerve, 1037 
plate, 96 
pudic artery in female, 692 
in male, 689 
vein, 760 
rectus oculi muscle, 373 
respiratory nerve of Bell, 974 
saphenous nerve, 1005 
vein, 756 
semilunar fibrocartilage, 338 
spermatic fascia, 446 
sphincter ani muscle, 451 
structure of cerebellum, 931 
supracondylar ridge, 180 
tarsal ligament, 370 
tuberosity of tibia, 233 
wall of tympanum, 1152 
Intemasal suture, 139 
Interneural articulations, 272 
Internodia or phalanges, 204 
Interolivary fillet, 909, 949 
Interossei muscles of foot, 548 
dorsal, 548 
plantar, 548 
of hand, 499 
Interosseous artery of ulnar, 662 
anterior, 662 
posterior, 663 
arteries, dorsal, 659, 715 
palmar, 660 
ligament, 286 
nerve, anterior, 987 
posterior, 991 
sacro-iliac ligament, 292 
veins of forearm, 747 
Interpalpebral slit, 1138 
Interparietal suture. 127 
Interpeduncular ganglion, 910 
space of brain, 882, 906 
Interpleural space, 1387 
Interpubic disk, 296 
Intersigmoid fossa, 1312 
Interspinales muscle, 421 
Interspinous ligaments, 273 
venous plexus, 732 
Intersternal ligament, anterior, 
290 
posterior, 290 
Intertransversales muscle, 422 
laterales muscle, 422 
mediates muscle, 422 
Intertransverse ligaments, 273, 
295 
Intertrochanteric line, anterior, 
223 
posterior, 223 
Intertubular cell-masses, 1352 
tissue, 1203 
Interventricular grooves, 568 
of heart, 565 
septum, 569 
Intervertebral disks, 270 
structure of, 271 
fibro-cartilages, 270 
structure of, 271 
foramina, 49 INDEX 
1571 
Intervertebral grooves, 49 
notches, 49 
substances, 270 
structure of, 271 
, veins, 755 
Intestinal glands, 1295, 1319 
Intestine, large, 1299 
areolar coat of, 1318 
arteries of, 1320 
flexure of, hepatic, 1300 
sigmoid, 1300 
splenic, 1300 
lymphatic glands of, 808, 
1321 
vessels of, 809 
mucous membrane of, 1318 
muscular coat of, 1317 
serous coat of, 1316 
structure of, 1316 
submucous coat of, 1318 
veins of, 1321 
innervation of, 1323 
movements of, 1322 
small, 1282 
areolar coat of, 1290 
arteries of, 1296 
lymphatic glands of, 807, 
1297 
vessels of, 808 
mucous membrane of, 1290 
muscular coat of, 1290 
nerves of, 1299 
serous coat of, 1290 
structure of, 1290 
submucous coat of, 1290 
veins of, 1297 
villi of, 1292 
surface form of, 1323 
surgical anatomy of, 1324 
Intestinum tenue mesenteriale, 
1289 
Intracapsular fracture, 229 
Intracartilaginous ossification, 43 
Intraepithelial plexus, 1111 
Intralobular veins, 767 
Intramembranous ossification, 43 
Intraparietal sulcus of Turner, 
875 
Intrathyroid cartilage, 1363 
Intrinsic muscles of tongue, 398 
Intumescentia ganglioformis, 
1045 
Involuntary muscles, 361 
Iris, 1117 
arteries of, 1120 
muscular fibres of, 1118 
nerves of, 1120 
pigment of, 1119 
stroma of, 1118 
structure of, 1118 
Irregular bones, 34 
Ischiatic lymphatic glands, 797 
Ischio-capsular ligament, 328 
-gluteal bursa, 331 
-rectal fascia, 454, 1546 
fossa, 1536 
region, muscles of, 449 
surgical anatomy of, 1535 
Ischium, 210 
body of, 210 
ramus of, ascending, 212 
descending, 211 
spine of, 211 
tuberosity of, 211 
Island of Langerhans, 1352 
of Reil, 867, 878 
Isthmus, aortic, 591 
of auditory canal, 1148 
cerebri, 906 
of Fallopian tube, 1497 
of fauces, 1212 
Isthmus, faucium, 1194 
of pharynx, 1221 
of prostate gland, 1451 
rhombencephali. 857 
of thyroid gland. 1403 
Iter a tertio ad quart um ven- 
triculum, 903, 912 
chordae anterius, 1152 
posterius, 1151 
Ivory of teeth, 1202 
J 
Jacob's membrane, 1126 
Jacobson, cartilage of, 1097 
eminence of, 1100 
nerve, 1056 
canal for, 90 
organ of, rudimentary, 1100 
Jaw, angle of, 124 
bones, upper, 105 
lower, articulations of, 280 
changes produced in, by age, 
125 
upper. See Maxillary Bone. 
Jejunum, 1289 
Joints. See Articulations. 
Jugular foramen, 73, 133 
fossa, 91 
ganglion, 1056 
glands, internal, 786 
lymphatic trunk, 787 
nerve, 1073 
process, 73 
tubercle, 74 
vein, anterior, 728 
external, 728 
sinus of, 728 
internal. 729 
bulb of, 729 
sinus of, 729 
surgical anatomy of, 732 
posterior external, 728 
Juxta-aortic glands, left, 800 
right, 800 
-cervical lymphatic knot, 803 
K 
Kerkring, valves of, 1291 
Key and Retzius, foramina of, 
834, 853 
Kidneys, 1411 
abnormalities of, 1424 
areas of, 1414 
arteries of, 1422 
calices of, 1415 
capsule of, fatty, 1411 
true, 1415 
connective tissue of, 1424 
cortical substance of, 1416 
ducts of, 1420 
hilum of, 1415 
infundibula of, 1415 
intermediate zone of, 1416 
lymphatic vessels of, 804, 1424 
Malpighian bodies of, 1417 
capsule, 1417 
tuft of, 1417 
medullary substance of, 1416 
minute anatomy of, 1417 
nerves of, 1424 
papillae of, 1417 
pelvis of, 1415 
pyramids of Ferrein, 1417 
of Malpighi, 1416 
sinus of, 1415 
structure of, 1415 
surface form of, 1425 
Kidneys, surfaces of, 1412 
surgical anatomy of, 1425 
tubuli uriniferi, 1418 
variations of, 1424 
veins of, 1424 
Knee, bursae of, 340 
-cap, 230 
-joint, surface form of, 343 
surgical anatomy of, 343 
ligaments of, 334 
Kolliker, membrane of, 1175 
Krause, ellipsoid of, 1127 
end-bulbs of, 827 
L 
Labia pudendi majora, 1477 
minora, 1478 
Labial artery, inferior, 607 
glands, 1194 
nerves, 1034 
Labii cerebri, 885 
Labium tympanicum, 1172 
vestibulare, 1172 
Labyrinth, 1163 
arteries of, 1176 
membranous, 1169 
nerves of, 1176 
osseous, 1164 
veins of, 1176 
Lachrymal apparatus, 1141 
artery, 623 
peculiarities of, 623 
bone, 112 
articulations of, 113 
attachment of muscles to, 
113 
borders of, 113 
crests of, 141 
development of, 113 
lesser, 113 
surfaces of, 113 
canaliculi, 1142 
canals, 1142 
caruncle, 1142 
crest, 113 
fossa, 81 
glands, 1141 
structure of, 1141 
surface form of, 1143 
surgical anatomy of, 1144 
groove, 107, 109, 141, 143 
nerve, 1028 
notch, 107 
papilla, 1138, 1142 
process of inferior turbinated, 
120 
sac, 1142 
structure of, 1142 
surface form of, 1143 
surgical anatomy of, 1144 
sulcus, 113 
tubercle, 109 
Lactiferous duct, 1507 
Lacuna magna, 1444 
Lacunae, 1110 
of bone, 38 
Howship's, 38 
Lacus lacrimalis, 1138 
Lagena, 1172 
Lalouette, pyramid of, 1403 
Lambda, 129 
Lambdoid suture, 75, 78, 128 
Lamella of bone, articular, 259 
Lamina basalis, 1114 
of cerebellum, 927 
cinerea, 882 
of cornea, 1109 
cribrosa, 89 
cribriform, 1108 1572 
INDEX 
Lamina, cribriform, of sclerotic, 
1108 
dental, 1205 
of ethmoid, horizontal, 99 
perpendicular, 100 
vertical, 100 
fusca, 1108 
posterior perforated, 910 
reticularis, 1175 
septi pellucidi, 889 
spiralis ossea of cochlea 1167 
suprachorioidea, 1112 
terminalis, 882 
vasculosa, 1112 
of vertebra, 34 
Lancisi, nerve of, 887 
Landzert, fossa of, 1262 
Langer, foramen of, 464, 646, 791 
lines of cleavage of, 1180 
Langerhans, centro-acinar cells 
of, 1352 
islands of, 1352 
Lantermann, segments of, 823 
Large, deep petrosal nerve, 1034, 
1073 
intestine, 1299 
palatine nerve, 1035 
superficial petrosal nerve, 1034 
Laryngeal artery, inferior, 641 
superior, 602 
.nerve, superior, 1060 
external, 1060 
internal, 1060 
pouch, 1371 
saccule, 1371 
sinus, 1371 
surface of epiglottis, 1365 
veins, 751 
Larynx, 1361 
aperture of, superior, 1368 
arteries of, 1375 
cartilages of, 1362 
cavity of, 1368 
compartments of, 1368 
lower, 1371 
middle, 1369 
glands of, 1374 
joints of, 1366 
ligaments of, 1366 
lymphatics of, 782, 1375 
membranes of, 136 
mucous membrane of, 1374 
muscles of, 1371 
action of, 1374 
nerves of, 1376 
rima glottidis, 1369 
structure of, 1365 
veins of, 1375 
ventricle of, 1371 
vocal cords of, false, 1370 
true, 1369 
Lateral acoustic tubercle, 950 
angle, inferior, 63 
cell column, 846 
column of medulla, 945 
fillet, 885 
fissures of cord, 838 
ligament, external, 280 
internal, 280 
of liver, 1334 
of wrist, 318 
masses of atlas, 51 
of ethmoid, 100 
odontoid ligaments, 278 
patellar ligaments, 335 
region of skull, 136 
root of eighth nerve, 1051 
sacral artery, 693 
veins, 760 
sacro-coccygeal ligament, 295 
sinus, 738 
Lateral sinus, surgical anatomv 
of, 739 
spinal arteries, 638 
surface of liver, 1329 
thoracic region, muscles of, 
468 
tract of medulla, 945 
ventricle of brain, 888 
body of, 889 
central cavity of, 889 
cornu of, anterior, 889 
descending, 890 
middle, 890 
posterior, 889 
horn of, frontal, 889 
occipital, 889 
temporal, 890 
vertebral region, muscles of, 
408 
Lateralis nasi artery, 607 
Latissimus dorsi muscle, 413 
bursa of, 474 
Leaf, condyloid glands of, 795 
supracondyloid glands of, 795 
Left bronchus, 1378 
cardiac vein, 771 
colic artery, 678 
plexus, 1085 
coronary artery, 590 
plexus, 1081 
vein, 770 
gastro-epiploic plexus, 1085 
innominate vein, 750 
juxta-aortic glands, 800 
lobe of liver, 1333 
lower azygos vein, 753 
marginal vein, 771 
superior intercostal vein, 752 
upper azygos vein, 753 
Leg, arteries of, 711 
bones of, 230 
fasciae of, 531 
ligaments of, 325 
muscles of, 531 
nerves of, 1006 
veins of, 755 
Lemniscus, 909, 949 
Lens, crystalline, 1130 
epithelium, 1130 
fibres, 1130 
suspensory ligament of, 1129 
Lenticular ganglion, 1031 
nucleus, 891 
Lenticulo-striate arteries, 628 
Lesser internal cutaneous nerve, 
986 
omentum, 1254 
sacro-sciatic foramen, 294 
ligament, 293 
sciatic nerve, 1011 
wing of sphenoid, 96 
Levator anguli oris muscle, 377 
scapulae muscle, 414 
ani muscle, 451 
preanal fibres of, 453 
glandulae thvroideae muscle, 
1403 
labii inferioris muscle, 378 
superior alaeque nasi muscle 
375 
superioris muscle, 376 
menti muscle, 378 
palati muscle, 403 
palpebrae muscle, 371 
superioris muscle, 372 
prostatae, 454 
urethrae, 454 
Levatores costarum muscle, 426 
Lieberkiihn, crypts of, 1295 
glands of, 1295, 1319 
Lieno-renal ligament, 1252, 1355 
Ligamenta alaria, 340 
sacro-coccygea, anterior, 452 
subflava, 272 
suspensoria of mamma, 463 
Ligamentous action of muscles, 
268 
Ligaments, 261 
accessory, of atlas, 276 
of acetabulum, transverse, 330 
acromio-clavicular, inferior, 
299 
superior, 299 
of ankle, 347 
annular, anterior, 541 
external, 542 
internal, 542 
of radius, 314 
of stapes, 1161 
anterior common, 269 
longitudinal, 269 
superior, 285 
appendiculo-ovarian of Clado, 
1304 
arcuate, external, 427, 449 
internal, 427 
middle, 427 
astragalo-scaphoid, 354 
atlanto-axial, anterior, 274 
posterior, 275 
atlo-axoid, anterior, 274 
posterior, 275 
of axilla, suspensory, 464 
of Bertin, 328 
of Bigelow, 328 
of bladder, false, 1436 
true, 1436 
broad, of liver, 1333 
of uterus, 1490 
calcaneo-astragaloid, external, 
352 
internal, 352 
posterior, 352 
-cuboid, internal, 353 
long, 353 
short, 353 
superior, 353 
-navicular, 353 
-scaphoid, external, 353 
inferior, 354 
internal, 354 
superior, 353 
capsular. See Individual Joints, 
carpo-metacarpal, 313 
of carpus, 319 
central, of spinal cord, 835 
check, 278, 1105 
chondro-sternal, anterior, 288 
interarticular, 288 
posterior, 288 
-xiphoid, anterior, 288 
posterior, 288 
ciliary, 1116 
of Cloquet, 1466 
coccjrgeal, 833 
Colles', 437 
conoid, 300 
of Cooper, 437, 448 
coraco-acromial, 301 
-clavicular, 300 
-humeral, 304 
coracoid, 302 
costo-clavicular, 298 
-coracoid, 467 
-transverse, long, 285 
middle, 286 
posterior, 286 
-vertebral, anterior, 284 
-xiphoid, anterior, 288 
posterior, 288 
cotyloid, 329 
crico-arytenoid, 1367 J^DEX 
1573 
Ligaments, crico-tracheal, 1368 
cruciform, 275 
deltoid, 348 
dentate, 835 
dorsal. See Individual .Joints, 
duodeno-mesocolic, 1261 
-renal, 1255 
of elbow, anterior, 309 
posterior, 309 
femoral, 515 
of fingers, 322 
superficial, transverse, 494 
Flood's, 304 
of foot, 547 
fundiform of Retzius, 541 
gastro-splenic, 1256 
Gimbernat's, 437, 1515 
gleno-humeral, 305 
glenoid, 175, 305 
of Cruveilhier, 359 
glosso-epiglottic, 1366 
of hand, 319 
of Helmholtz, 1160 
of Henle, 438, 442 
hepato-colic, 1255 
-duodenal, 1255 
-gastric, 1254 
of Hesselbach, 438, 442, 1517 
of Hey, 515 
of hip, 326 
hyo-epiglottic, 1365 
ilio-femoral, 328 
-lumbar, 291 
* -pectineal, 508 
-trochanteric, 329 
of incus, 1161 
infundibulo-pelvic, 1490 
interarticular, 284, 329 
interchondral, external, 290 
internal, 290 
interclavicular, 298 
interosseous. See Individual 
joints. 
interspinous, 273 
intersternal, anterior, 290 
posterior, 290 
intertransverse, 273, 295 
-. intervertebral, 270 
ischio-capsular, 328 
of jaw, 280 
of knee, 334 
alar, 340 
anterior, 345 
coronary, 340 
crucial, 337 
mucosum, 334 
posterior, 335 
transverse, 340 
of larynx, 1366 
lateral. See Individual Joints, 
lieno-renal, 1252, 1355 
of liver, 1333 
coronary, 1334 
falciform, 1333 
lateral, of, 1334 
left, 1334 
right, 1334 
round, 1334 
suspensory, 1333 
lumbo-sacral, 291 
of Luschka, 558 
of malleus, 1160 
metacarpal, 324 
metacarpo-phalangeal, 324 
--'metatarsal, 359 
metatarso-pharyngeal, 359 
nuchae, 273, 413 
oblique, 314 
.-^ obturator, 296 
occipito-atlantal, anterior, 276 
posterior, 276 
Ligaments, occipito-axial, 278 
odontoid, lateral, 278 
middle, 279 
orbicular, 314 
orbito-tarsal, 1139 
of ossicula, 1160 
palpebral, 1139 
of patella, 335 
. . pelvis, falciform, 293 
transverse, 459 
of penis, 1458 
suspensory, 437 
perineal, transverse, 459 
of peritoneum, 1254 
of phalanges of foot, 359 
of hand, 325 
phreno-colic, 1259 
-- -pericardial, 559 
plantar, long, 353 
short, 353 
posterior common, 270 
-longitudinal, 270 
Poupart's, 436, 1515 
pterygo-mandibular, 380 
-maxillary, 380 
pubic, anterior, 296 
inferior, 296 
posterior, 296 
superior, 296 
pubo-capsular, 328 
-femoral, 328 
-prostatic, 1435, 1451 
-vesical, 1435 
radio-carpal, 319 
-ulnar, annular, 314 
anterior, 315 
oblique, 314 
orbicular, 314 
round, 314 
posterior, 315 
rhomboid, 298 
sacro-coccygeal, anterior, 294 
lateral, 295 
posterior, 294 
-iliac, anterior, 292 
interosseous, 292 
long, 292 
oblique, 292 
posterior, 292 
short, 292 
-sciatic, anterior, 293 
great, 292 
lesser, 293 
posterior, 292 
-uterine, 1490 
-vertebral, 291 
of scapula, 301 
Sc hie mm's, 305 
of shoulder, 303 
spino-glenoid, 302 
spiral, of cochlea, 1172 
- spleno-phrenic, 1256 
sterno-clavicular, anterior, 298 
posterior, 298 
-costal, anterior, 288 
interarticular, 288 
posterior, 288 
-costo pericardial, 559 
-pericardiac, 558 
of stapes, 1161 
of sternum, 290 
stylo-hyoid, 394 
-mandibular, 281, 388 
-maxillary, 281 
subpubic, 296 
suprascapular, 302 
supraspinous, 273 
suspensory, of clitoris, 437 
of eye, 1105 
- of incus, 1161 
of lens, 1129 
Ligaments, suspensory, of liver, 
1333 
~- of mamma, 463 
of ovary, 1501 
of penis, 437 
* of Treitz, 1286 
- sutural, 259 
-* synovial, 262 
tarsal, external, 370 
internal, 370 
of thumb, 321 
thyro-epiglottic, 1367 
-hyoid, 1366 
- tibio-tarsal, anterior, 347 
posterior, 347 
transverse, of atlas, 275 
humeral, 305 
inferior, 302 
of knee, 340 
superior, of scapula, 302 
trapezoid, 300 
- tympano-malleolar, 1156 
utero-sacral, 1490 
of uterus, 1489 
round, 1491 
of vertebrae, 270 
-- vertebro-pericardial, 558 
- -pleural, 1385 
- vesico-uterine, 1490 
of Winslow, 335 
- of Wrisberg, 339 
of wrist, 318 
anterior, 318 
dorsal, 318 
lateral, external, 318 
internal, 318 
posterior, 318 
volar, 318 
- xipho-pericardial, 559 
Y-, 328 
of Zinn, 373 
Ligamentum arcuatum exter- 
num, 427, 449 
internum, 427 
arteriosum, 587 
conjugale, 284 
corniculopharyngeum, 1368 
crico-pharyngeum, 1368 
denticulatum, 835 
epididymidis, 1469 
hepatoduodenale, 1250 
latum pulmonalis, 1385 
mucosum, 340 
nuchae, 273, 413 
patellae, 335 
posticum Winslowii, 335 
pulmonale, 1385 
spirale, 1172 
suspensorium, 279 
teres, 329 
ventriculare, 1366 
Light stimuli, path of, 1127 
Ligula, 944 
Limbic lobe, 878 
convolutions of, 879 
Limbus alveolaris, 124 
laminae spiralis, 1172 
Limen insulae, 878 
Limiting sulcus of Reil, 867 
Linea alba, 444 
aspera, 224 
external lip of, 224 
internal lip of, 224 
quadrati, 224 
splendens, 835 
Linae semilunares, 445 
transverse, of abdomen, 445 
Line, gluteal, anterior, 207 
inferior, 208 
posterior, 207 
ilio-pectineal, 209 1574 
INDEX 
Line, nuchal, inferior, 72 
superior, 72 
temporal, 76, 80 
Lingual artery, 603 
branches of, 603 
deep, 604 
relations of, 603 
surgical anatomy of, 604 
bone, 153 
gyrus, 877 
nerve, 1038, 1057 
branches of, 1038 
region, muscles of, 396 
dissection of, 396 
tonsil, 1088 
veins, 729 
Lingualis muscle, inferior, 399 
superior, 399 
transverse, 399 
vertical, 399 
Lingula, 93, 280, 928, 944 
pulmonis, 1392 
Lips, 1194 
surgical anatomy of, 1224 
Liquor Cotunnii, 1164 
Lissauer, tract of, 843 
Little brain, 926 
Littr6, glands of, 1444 
Liver, 1326 
^abnormalities of, 1335 
accessory, 1335 
areolar coat of, 1337 
arteries of, 1336 
development of, 1243 
ducts of, 1341 
excretory apparatus of, 1342 
fibrous coat of, 1337 
fissures of, 1330 
hepatic arteries, 1336 
ducts, 1336 
vein, 1336 
ligaments of, 1333 
lobes of, 1332 
lobules of, 1337 
lymphatics of, 805, 1341 
margins of, 1330 
movability of, 1334 
nerves of, 1342 
portal vein, 1336 
serous coat of, 1337 
structure of, 1337 
support of, 1334 
surface relations of, 1346 
surfaces of, 1327, 1329 
surgical anatomy of, 1346 
veins of, 1336 
Lobe or lobes, biventral, 931 
of brain, 872 
central, 878 
of cerebellum, 926,928,930,931 
crescentic, anterior, 928 
posterior, 928 
cuneate, 877 
digastric, 931 
frontal, 872, 884 
of kidney, 1415 
limbic, 878 
of liver, 1332 
of lungs, 1392 
occipital, 876 
olfactory, 880 
orbital, 874 
parietal, 875 
post-central, 878 
pre-central, 878 
of prostate gland, 1451 
quadrate, 876 
semilunar, inferior, 931 
slender, 931 
temporal, 877, 885 
temporo-sphenoidal, 877 
Lobe or lobes, of testicle, 1472 
of thymus gland, 1407 
of thyroid gland, 1403 
Lobule of ear, 1145 
of kidney, 1415 
of liver, 1337 
of lungs, 1395 
of mamma, 1506 
Lobuli testis, 1472 
Lobulus centralis, 928 
Locus cseruleus, 945 
Long bones, 33 
calcaneo-cuboid ligament, 353 
ciliary arteries, 625 
nerves, 1030 
plantar ligament, 353 
sacro-iliac ligament, 292 
saphenous nerve, 1005 
vein, 756 
scrotal nerve, 1011 
subscapular nerve, 984 
thoracic artery, 651 
nerve, 983 
vein, 748 
Longissimus dorsi muscle, 419 
Longitudinal fasciculus, inferior, 
918 
superior, 918 
fibres of cord, 841 
of pons, 923 
dorsal, 924 
deep, 924 
middle, 924 
superficial, 924 
ventral, 924 
deep, 924 
fissure of cerebrum, 865, 882 
sinus, inferior, 738 
superior, 78, 130, 736 
Longus capitis muscle, 406 
colli muscle, 407 
Looped tubes of Henle, 1419 
Louis, angle of, 157 
Lower deep cervical glands, 787 
extremity, arteries of, 697 
articulations of, 325 
bones of, 206 
fasciae of, 507 
ligaments of, 325 
lymphatic vessels of, 797 
deep, 797 
superficial, 797 
muscles of, 507 
surface form of, 549 
surgical anatomy of, 551 
nerves of, 997 
veins of, 755 
deep, 758 
superficial, 756 
jaw, articulation of, 280 
subscapular nerve, 984 
visual centre, 1022 
Ludovic, angle of, 157 
Lumbar arteries, 680 
fascia, 416 
ganglia, 1085 
glands, 799 
nerves, 997 
divisions of, anterior, 998 
posterior. 997 
roots of, 997 
plexus, 998 
branches, 999 
surgical anatomy of, 1017 
portion of gangliated cord, 
1079 
region,' 1233 
veins, 765 
ascending, 753, 765 
right, 752 
vertebrae, 56 
Lumbar vertebrae, body of, 56 
fifth, 57 
laminae of, 56 
pedicles of, 56 
processes of, 57 
Lumbo-iliac ligament, 291 
-sacral ligament, 291 
plexus, 998 
Lumbricales muscle,, foot, 546 
hand, 499 
Lungs, 1390 
air-cells of, 1396 
apex of, 1390 
arteries of, 1396 
base of, 1391 
borders of, 1392 
bronchus of, 1395 
capillaries, 1396 
color of, 1394 
fissures of, 1392 
foetal, 1394 
lobes of, 1392 
lobules of, 1395 
lymphatics of, 1396 
nerves of, 1397 
parenchyma of, 1395 
root of, 1394 
serous coat of, 1394 
structure of, 1394 
subserous areolar coat of, 1394 
■ substance of, 1394 
surface form of, 1397 
surfaces of, 1391, 1394 
surgical anatomy of, 1397 
veins of, 1396 
weight of, 1394 
Lunula of nails, 1185 
Luschka, gland of, 1410 
ligament of, 558 
villi of, 854 
Luys, nucleus of, 908, 910 
Lymph canalicular system, 772 
-capillaries, 772 
-glands, parotid, 1215 
-nodes, 774 
perivascular, 772 
-spaces, 772 
Lymphatic or lymphatics, 772 
of arm, 788 
of arteries, 586 
of bone, 41 
of cord, 840 
of cranial region, 779 
duct, right, 778 
tributaries of, 779 
of dura mater of brain, 848 
extracranial, 780 
of face, 779 
glands, 774 
of abdomen. 797 
abdomino-aortic, 799 
along mesenteric arteries, 
800 
of anus, 809 
axillary, 790 
brachial, 788 
bronchial, 1380 
buccal, 782 
buccinator, 782 
carotid, 786 
cervical, deep, 786 
superficial, 784 
of Cloquet, 795, 798 
cceliac, 800 
colic, 808 
condyloid of Leaf, 795 
connected with cceliac axis 
and branches, 800 
diaphragmatic, 810 
epigastric, superior, 802 
of face, 780 INDEX 
1575 
Lymphatic or lymphatics, glands, 
femoral, deep, 795 
gastric, 800 
genial, 782 
gluteal, 797 
haemorrhoidal, middle, 799 
of head, 780 
hepatic, 800 
hypogastric, 799 
iliac, 797 
common, 799 
external 797 
internal, 799 
ilio-pelvic, 797 
infralaryngeal, 787 
inframaxillary, 782 
inguinal, deep, 795 
superficial, 793 
intercostal, 810 
intermediate, 791 
of intestine, large, 808 
small, 807 
ischiatic, 797 
jugular, external, 784 
internal, 786 
juxta-aortic, left, 800 
right, 800 
•of lower extremity, 793 
lumbar, 799 
malar, 782 
mammary, internal, 810 
mastoid, 780 
maxillary, internal, 782 
mediastinal, anterior, 811 
posterior, 812 
middle, of Stahr, 784 
of neck, 784 
obturator, 798 
occipital, 780 
paramammary, 813 
parietal, 810 
parotid, 781 
deep, 782 
superficial, 781 
pectoral, 790 
of pelvis, 797 
peritracheo-bronchial, 812 
posterior auricular retro- 
auricular, 780 
post-pharyngeal, 785 
pre-aortic, 800 
pre-auricular, 781 
prelaryngeal, 787 
pretracheal, 787 
popliteal, 795 
rectal, 809 
retro-aortic, 800 
-crural, 798 
-pharyngeal, 785 
of Rosenmuller, 795 
sacral, 799 
saphenous, external, 795 
scapular, 790 
splenic, 800 
sterno-mastold, 786 
subclavian, 791 
submaxillary, 784 
submental, 785 
suboccipital, 780 
suborbital, 782 
subparotid, 782 
substerno-mastoid, 786 
supraclavicular, 787 
supracondyloid of Leaf, 
795 
supraepitrochlear, 789 
suprahyoid, lateral, 784 
median, 785 
supramaxillary, 782 
supratrochlear, 789 
surgical anatomy of, 774 
Lymphatic or lymphatics, glands, 
of thoracic wall, 810 
tibial, anterior, 795 
tracheal, 787 
of upper extremity, 788 
deep, 790 
superficial, 788 
visceral, 811 
zygomatic, 782 
pharyngeal ring, 1224 
vessels of abdomen, 801 
walls of, deep, 801 
superficial, 801 
of bile-ducts, 806 
of bladder, 802 
cardiac, 815 
cerebral, 779 
of cranial region, 782 
of face, 782 
of Fallopian tube, 804 
of gluteal region, 801 
of head, 782 
of heart, 577 
of intestines, large, 809 
small, 808 
of kidney, 804 
of larynx, 782 
of leg. 797 
of liver, 805 
of lower extremity, 797 
deep, 797 
superficial, 797 
of lung, 815 
meningeal, 779 
of mouth, 782 
of neck, 779, 787 
of nose, interior of, 782 
of oesophagus, 815 
of ovary, 804 
of pancreas, 807 
of pelvis, 801 
of penis, 801 
of perina-um, 801 
of peritoneum, 802 
of pharynx, 782 
pleural, 815 
of prostate gland, 803 
pulmonary, 815 
of scrotum, 801 
of seminal vesicles, 804 
of spleen, 807 
of stomach, 806 
of suprarenal capsule, 804 
of testicle, 804 
of thoracic trachea, 815 
wall, 812 
thymic, 815 
of thyroid gland, 782 
of tongue, 782 
of umbilicus, 802 
of upper extremity, 792 
deep, 792 
superficial, 792 
of ureter, 804 
of urethra, female, 803 
male, 803 
of uterus, 803 
of vagina, 804 
of vas deferens, 804 
Lyra of fornix, 896 
M 
Macula acustica sacculi, 1170 
cribrosa, 1164 
lutea, 1128 
Magnum of carpus, 199 
Majendie, foramen of, 834, 853 
Malar bone, 113 
articulations of, 115 
Malar bone, attachment of mus- 
cles to, 115 
borders of, 115 
development of, 115 
processes of, 114 
surfaces of, 113 
canal, 114 
foramen, 113 
glands, 782 
nerve, 1032, 1049 
process of superior maxillary, 
109 
Male breast, 1509 
surgical anatomy of, 1509 
organs of generation, 1447 
perineum, 1537 
urethra, 1441 
Malleolar artery, 713, 719 
Malleolus, external, 238 
internal, 235 
Malleus, 1158 
handle of, 1158 
head of, 1158 
ligaments of, 1160 
manubrium of, 1158 
neck of, 1158 
processes of, 1158 
spur of, 1158 
Malpighi, pyramids of, 1416 
Malpighian bodies of kidney, 
1417 
of spleen, 1358 
capsule, 1417 
layer of skin, 1182 
tuft, 1417 
Mamma, 1503 
areola of, 1504 
arteries of, 1508 
ligament of, suspensory, 463 
lobule of, 1506 
lymphatics of, 1508 
nerves of, 1508 
variations in, 1504 
veins of, 1508 
Mammary artery, external, 651 
internal, 643 
branches of, 644 
surgical anatomy of, 645 
glands, 1503 
description of, 1503 
internal, 810 
lymphatics of, 812 
surgical anatomy of, 814 
structure of, 1505 
surgical anatomy of, 1508 
tissue, prolongations of, 1505 
vein, internal, 750 
Mammillary duct, 1507 
process of lumbar vertebra, 57 
Mandible, 122 
Mandibular artery, 614 
fossa, 84 
nerve, 1036 
region, muscles of, 377 
dissection of, 377 
Manubrium of malleus, 1158 
of sternum, 157 
Marchi and Lowenthal, column 
of, 843 
Marginal artery, 500 
convolution, 873 
gyrus, 875 
lobe, 857 
tract of Spitzka and Lissauer, 
843 
vein, left, 771 
Marrow of bone, 36 
Marshall, vein of, oblique, 771 
vestigial fold of, 561 
Martinotti, cells of, 921 
Masseter muscle, 381 1576 
INDEX 
Masseteric artery, 615 
fascia, 381 
nerve, 1037 
vein, 727 
Mast-cells, 36 
Mastoid air-cells, 1153 
antrum, 87 
artery, 609, 610 
cells, 86 
foramen, 85, 138 
fossa, 86 
lymphatic glands, 780 
nerves, 973 
process, 86, 138 
vein, 728 
Masto-occipital suture, 75, 128 
-parietal suture, 128 
Matrix of nails, 1185 
Maxillary antrum, orifice of, 145 
artery, external, 604 
internal, 612 
bone, inferior, 122 
articulation of, 125 
attachment of muscles to, 
125 
development of, 125 
horizontal portion of, 122 
borders of, 124 
surfaces of, 122 
perpendicular portion of, 
124 
borders of, 124 
processes of, 125 
surfaces of, 124 
superior, 105 
articulations of, 112 
attachment of, 112 
body of, 105 
surfaces of, 106 
development of, 112 
processes of, 109 
hiatus, 107 
lymphatic glands, internal, 782 
nerve, inferior, 1036 
superior, 1031 
branches of, 1032 
process of inferior turbinated, 
120 
of malar, 115 
of palate bone, 117 
region, superior muscles of, 376 
sinus, 108 
tuberosity, 106 
vein, internal, 727 
McBurney's point, 1303 
Meatus, auditory, external, 88, 
138, 1148 
internal, 89, 133 
of nose, inferior, 145 
middle, 145 
superior, 101, 144 
urinarius, male, 1444 
female, 1481 
Meckel, band of, 1160 
cavity of, 848 
diverticulum, 1290 
ganglion, 1034 
branches of, 1034, 1035 
Median nerve, 986 
branches of, 987 
vein, 745 
basilic, 746 
cephalic, 746 
cerebral, 735 
Mediastinal arteries, 644 
posterior, 666 
glands, anterior, 811 
posterior, 812 
pleura, 1385 
subpleural, 644 
space, 1387 
Mediastinal surface of lungs, 
1391 
Mediastinum, 1388 
anterior, 1389 
arteries of, 1390 
lymphatics of, 1390 
middle, 1389 
posterior, 1389 
superior, 1388 
testis, 1471 
veins of, 1390 
Medio-tarsal joint, 350, 355 
Medulla oblongata, 884, 938 
fibres of, 942 
fissures of, 939 
formatio reticularis of, 947 
funiculus cuneatus, 941 
gracilis of, 941 
of Rolando, 941 
gray matter of, 945 
lateral column of, 940 
tract of, 945 
olivary body of, 941 
pyramid of, 939 
raph£ of, 951 
restiform body of, 941 
structure of, internal, 945 
surfaces of, posterior, 941 
veins of, 736 
spinalis, 884 
Medullary canal, 857 
portion of suprarenal capsule, 
1431 
of thymus gland, 1408 
spaces of bone, 45 
substance of kidneys, 1416 
tube, 857 
velum, anterior, 943 
inferior, 943 
posterior, 943 
superior, 943 
Medullated nerve-fibres, 822 
Medulli-spinal veins, 755 
Meibomian glands, 1139 
structure of, 1140 
surgical anatomy of, 1143 
Membrana basilaris, 1172 
cochlea ductus cochlearis, 1172 
elastica laryngis, 1367 
flaccida of Shrapnell, 1156 
limitans externa of retina, 1126 
interna, 1122 
nictitans, 1140 
pupillaris, 1120 
quadrangularis, 1366 
sacciformis, 317 
tectoria, 1175 
tympani, 1155 
arteries of, 1157 
lymphatics of, 1158 
nerves of, 1158 
secundaria, 1167 
structure of, 1157 
veins of, 1157 
Membrane, basilar, 1172 
Bowman's, 1109 
of brain, arachnoid, 851 
meningeal, 847 
of Bruch, 1114 
of choroid, 1112 
of Corti, 1175 
costo-coracoid, 467 
crico-thyroid, 1367 
of Demours, 1110 
of Descemet, 1110 
fenestrated, of Henle, 585 
hyaloid, 1129 
hyo-thyroid, 1366 
of Jacobs, 1126 
of Kolliker, 1175 
Nasmyth's, 1204 
Membrane, obturator, 525 
occipito-atlantal, anterior, 276 
posterior, 276 
otolith, 1172 
of Reissner, 1172 
of Scarpa, 1152 
of Shrapnell, 1156 
of spinal cord, 832 
arachnoid, 834 
surgical anatomy of, 836 
sutural, 264, 847 
synovial, 262 
thyro-hyoid, 1366 
Membranous canal of cochlea, 
1172 
cranium, 102 
labyrinth, 1169 
portion of urethra, 1442 
semicircular canals, 1170 
Meningeal artery, 609, 610 
anterior, 622 
middle, 613 
surgical anatomy of, 614 
posterior, 638 
small, 614 
lymphatic vessels, 779 
membranes of brain, 847 
nerve, 1032 
veins, 730, 734 
Meninges of brain, 847 
Meningo-rachidian veins, 754, 
833 
Menisco-femoral joint, 342 
-tibial joint, 342 
Meniscus, 281 
Mental foramen, 123, 140 
nerve, 1039 
process, 122, 140 
protuberance, 122 
spines, 123 
tubercles, 122 
Merkel, filtrum ventriculi of, 
1368 
Mesencephalon, 906 
Mesenteric arteries, glands along, 
800 
artery, inferior, 677 
superior, 675 
ganglion, 1085 
plexus, inferior, 1085 
superior, 1085 
vein, inferior, 768 
superior, 768 
Mesenterico-mesocolic fold, 1262 
-parietal fold, 1264 
Mesentery, 1257 
development of, 1237 
glands, 807 
of vermiform appendix, 1260i 
Mesoappendix, 1260 
Mesoblastic somites, 1235 
Mesocsecum, 1301 
Mesochorium, 1461 
Mesocolic area of kidney, 1414 
band, 1317 
fossa, 1261 
Mesocolon, ascending, 1258 
descending, 1258 
sigmoid, 1259 
transverse, 1259, 1309 
Mesogastrium, 1237 
Mesognathion, 111 
Mesorectum, 1259 
Mesosalpinx, 1490 
Mesosternum, 159 
Mesovarium, 1490, 1500 
Metacarpal bones, 200 
ligament, transverse, 324 
spaces, 201 
Metacarpo-phalangeal articula- 
tions, 324, 359 INDEX 
1577 
Metacarpo-phalangeal articula- 
tions, surface form of, 325 
Metacarpus, 200 
articulations of, 204 
common character of, 200 
development of, 205 
peculiar characters of, 201 
Metasternum, 159 
Metatarsal artery, 715 
bones, 249 
fifth, 252 
first, 249 
fourth, 251 
peculiar characters of, 249 
second, 250 
third, 251 
ligament, transverse, 359 
Metatarsus, 249 
articulations of, 252 
common characters of, 249 
development of, 253 
Metencephalon, 858 
Metopic suture, 83, 127 
Meynert, commissure of, 908 
Mid-brain, 906 
Middle arcuate ligament, 427 
cardiac nerve, 1077 
cerebellar peduncles, 934 
cerebral artery, 627 
cervical ganglion, 1076 
clinoid processes, 93, 132 
colic artery, 676 
commissure, 903 
constrictor muscle, 401 
cornu of lateral ventricle, 
890 
costo-transverse ligament, 286 
cutaneous nerve, 1004 
ear, 1150 
fossa of skull, 130 
frontal convolution, 873 
hemorrhoidal artery, 687 
gland, 799 
veins, 760 
inguinal fossa, 1520 
internal frontal artery, 627 
meatus of nose, 145 
mediastinum, 1389 
meningeal artery, 613 
veins, 734 
occipital convolution, 877 
sulcus, 876 
odontoid ligament, 52, 279 
palatine nerve, 1035 
peduncle of cerebellum, 922 
sacral artery, 681 
veins, 764 
spermatic fascia, 440 
subscapular nerve, 984 
superior dental nerve, 1033 
temporal artery, 611 
convolution, 877 
vein, 727 
thyroid vein, 730 
turbinated bone, 107 
vesical artery, 686 
Mid-gut, 1236 ' 
Milk teeth, 1196 
Minor cardiac nerve, 1077 
Mitral orifice, 568 
Mixed bones, 34 
Mobile septum, 1097 
Moderator band, 570 
Modiolus, 1167 
Molar glands, 1195 
teeth, 1198 
Moll, glands of, 1138 
Monoaxonic cells, 821 
Monro, foramen of, 889 
Mons Veneris, 1477 
Montgomery, glands of, 1504 
Monticulus cerebelli, 927 
Morgagni, columns of, 1319 
crypts of, 1319 
hydatids of, 1469 
sinus of, 402 
valves of, 1319 
Motor oculi nerve, 1024 
surgical anatomy of, 
1025 
projection fibres of cerebrum, 
914 
tract, 939 
Mouth, 1193 
angle of, 1193 
aperture of, 1193 
cavity of, 143 
proper, 1194 
floor of, lymphatic vessels of, 
782 
mucous membranes of, 1194 
muscles of, 376 
surface form of, 1219 
surgical anatomy of, 1224 
vestibule of, 1194 
Movable spleen, 1356 
Movements admitted in joints, 
266 
Mucilaginous glands, 262 
Mucous alveoli, 1218 
coat of bladder, 1437 
of gall-bladder, 1343 
of oesophagus, 1229 
of pharynx, 1223 
of urethra, 1444, 1446 
glands of tongue, 1218 
Muller's muscle, 374 
"ring" muscle, 1116 
Multifidus spinae muscle, 421 
Multipolar cells, 820 
Muscle or muscles, 361 
of abdomen, 432 
deep, 449 
superficial, 432 
abductor hallucis, 544 
indicis, 499 
minimi digiti, foot, 544 
hand, 498 
pollicis, 495 
accelerator urin®, 457 
accessorius ad ilio-costalem, 
419 
pedis, 546 
of acromial region, 470 
adductor brevis, 520 
longus, 519 
magnus, 520 
minimus, 520 
obliquus hallucis, 546 
pollicis, 497 
transversus hallucis, 548 
pollicis, 497 
anconeus, 487 
antitragicus, 1147 
of arm, 470, 474 
arytenoid, 1375 
aryteno-epiglottideus, 1373 
arytenoideus, 1372 
attollens auriculam, 369 
attrahens auriculam, 369 
of auricular region, 369 
azygos uvulae, 405 
of back, 410 
biceps, arm, 475 
flexor cubiti, 475 
thigh, 520 
bipenniform, 363 
biventer cervicis, 420 
Bowman's, 1115 
brachialis anticus, 476 
buccinator, 380 
bulbo-cavernous, 557 
Muscle or muscles, cervicalis as- 
cendens, 419 
chondro-glossus, 397 
ciliary of eye, 1115 
circumflexus, 404 
coccygeus, 455 
complexus, 420 
compressor narium minor, 376 
nasi, 376 
sacculi laryngis, 1373 
urethrae in female, 462 
in male, 460 
constrictor, isthmi faucium, 
398, 405 
pharyngeus, inferior, 400 
middle, 401 
superior, 401 
urethrae in female, 462 
in male, 460 
coraco-brachialis, 475 
corrugator cutis ani, 449 
supercilii, 371 
of cranium, 365 
cremaster, 439, 1516 
crico-arytenoid, posterior, 1372 
-thyroid, 1372 
crureus, 517 
deltoid, 470 
depressor al® nasi, 376 
anguli oris, 378 
labii inferioris, 378 
detrusor urin®, 1437 
diaphragm, 427 
digastric, 393 
dilator naris anterior, 376 
posterior, 376 
of dorsal region, 543 
ejaculator seminis, 457 
urinae, 457 
erector clitoridis, 461 
penis, 458 
spinae, 417 
of expression, 385 
of expiration, 432 
extensor brevis digitorum, 543 
pollicis, 489 
carpi radialis brevior, 485 
longior, 485 
ulnaris, 487 
coccygis, 422 
communis digitorum, 486 
indicis, 490 
longus digitorum, 533 
pollicis, 489 
minimi digiti, 487 
ossis metacarpi pollicis, 489 
primi internodii pollicis, 489 
proprius hallucis, 532 
secundi internodii pollicis, 
489 
of face, 365 
of femoral region, anterior, 512 
internal, 519 
posterior, 529 
of fibular region, 539 
flexor accessorius, 546 
brevis digitorum, 544 
hallucis, 546 
minimi digiti, foot, 547 
hand, 498 
pollicis, 497 
carpi radialis, 479 
ulnaris, 480 
longus digitorum, 538 
hallucis, 538 
pollicis, 482 
ossis metacarpi, 498 
pollicis, 496 
profundus digitorum, 482 
sublimis digitorum, 481 
of forearm, 478 1578 
INDEX 
Muscle or muscles, of foot, 541 
frontalis, 368 
fusiform, 362 
gastrocnemius, 534 
gemellus, inferior 527 
superior, 526 
genio-glossus, 396 
-hyo-glossus, 396 
-hyoid, 395 
of gluteal region, 522 
gluteus maximus, 522 
medius, 523 
minimus, 523 
gracilis, 519 
hamstring, 529 
of hand, 491 
of head, 385 
helicis major, 1147 
minor, 1147 
Hilton's, 1373 
of hip, 522 
Horner's, 371 
of humeral region, anterior, 
474 
posterior, 477 
hyo-glossus, 397 
of iliac region, 508 
iliacus, 510 
ilio-capsularis, 511 
-coccygeus, 454 
-costalis, 419 
infracostales, 425 
of infra-hyoid region, 391 
infraspinatus, 472 
insertion of, 363 
of inspiration, 432 
intercostal, 425 
external, 425 
internal, 425 
of intermaxillary region, 378 
interossei of foot, 548 
of hand, 499 
interspinales, 421 
intertransversales, 422 
lateralis, 422 
mediales, 422 
involuntary, 361 
of ischio-rectal region, 449 
labial, 378 
of larynx, 1373 
latissimus dorsi, 413 
of leg, 531 
levator anguli oris, 377 
scapulae, 414 
ani, 451 
glandular thyroidea*, 1403 
labii inferioris, 378 
menti, 378 
superioris, 376 
alaeque nasi, 375 
palati, 403 
palpebrae, 371 
superioris, 372 
prostatae, 454 
urethrae, 454 
levatores costarum, 426 
ligamentous action of, 268 
of lingual region, 396 
lingualis, inferior, 399 
superior, 399 
transverse, 399 
vertical, 399 
longissimus dorsi, 419 
longus capitis, 407 
colli, 407 
of lower extremity, 507 
lumbricales, foot, 546 
hands, 497 
of mandibular region, 377 
masseter, 381 
of maxillary region, 376 
Muscle or muscles, Muller's, 374 
rnultifidus spina?, 421 
mylo-hyoid, 394 
of nasal region, 375 
naso-labialis, 380 
of neck, 385 
oblique, ascending, 437 
descending, 433 
external, 433 
internal, 437, 1516 
obliquus auriculae, 1147 
capitis inferior, 422 
superior, 422 
oculi, inferior, 374 
superior, 373 
obturator extern us, 528 
internus, 525 
occipitalis, 368 
occipito-frontalis, 367 
omo-hyoid, 393 
opponens minimi digiti, 498 
pollicis, 496 
orbicular, 363 
orbicularis oris, 378 
palpebrarum, 370 
orbital, 374 
region, 372 
of palatal region, 403 
palato-glossus, 398, 405 
-pharyngeus, 405 
of palmar region, middle, 499 
palmaris brevis, 498 
longus, 480 
of palpebral region, 370 
pectineus, 519 
pectoralis major, 464 
minor, 468 
of pelvic outlet, 449 
penniform, 363 
of perinaeum in female, 460 
in male, 455 
peroneus brevis, 540 
longus, 539 
tertius, 534 
of pharyngeal region, 400 
pharyngo-glossus, 398 
of plantar region, 544 
plantaris, 536 
platysma myoides, 386 
popliteus, 537 
pronator quad rat us, 483 
radii teres, 479 
psoas magnus, 509 
parvus, 510 
of ptervgo-mandibular region, 
383 ' 
pterygoid, external, 383 
internal, 383 
pubococcvgeus, 452 
pyramidalis abdominis, 444 
nasi, 375 
pyriformis, 524 
quadratus femoris, 527 
lumborum, 449 
menti, 378 
quadriceps extensor, 516 
quadrilateral, 362 
of radial region, 484, 495 
of radio-ulnar region, poste- 
rior, 486 
recto-urethralis, 454 
-uterinus, 1491 
rectus abdominis, 442 
capitis anticus major, 406 
minor, 407 
lateralis, 407 
posticus major, 422 
minor, 422 
femoris, 516 
oculi, external, 373 
inferior, 373 
Muscle or muscles, rectus oculi, 
internal, 373 
superior, 373 
retrahens auriculum, 369 
rhomboidal, 363 
rhomboideus major, 414 
minor, 414 
"ring" of Muller, 1116 
risorius, 380 
rot at ores spina*, 421 
sacro-lumbalis, 419 
salpingo-pharyngeus, 405 
Santorini's, 380 
sartorius, 516 
scalenus anticus, 408 
medius, 408 
posticus, 409 
of scapular region, anterior, 
471 
posterior, 472 
semicircular, of rectum, 1317 
semimembranosus, 530 
semispinalis colli, 421 
dorsi, 421 
semitendinosus, 530 
serratus magnus, 468 
posticus inferior, 415 
superior, 415 
of shoulder, 470 
skeletal, 361 
of sole of foot, 544 
soleus, 535 
sphincter, 363 
ani, external, 450 
internal. 451 
vaginae, 461 
spinalis colli, 420 
dorsi, 419 
splenius, 416 
capitis, 416 
colli, 416 
sterno-cleido-mastoid, 389 
-hyoid, 391 
-mastoid, 389 
-thyroid, 392 
striated, 361 
striped, 361 
stylo-glossus, 397 
-hyoid, 394 
-pharyngeus, 403 
subanconeus, 478 
subclavius, 468 
subcrureus, 518 
subscapularis, 471 
of superficial cervical region, 
386 
supinator longus, 484 
radii brevis, 487 
of supra-hyoid region, 393 
supraspinales, 421 
supraspinatus, 472 
suspensory, of duodenum, 1286 
temporal, 382 
of temporo-mandibular region 
381 
tensor fascia* femoris, 515 
palati, 404 
tarsi, 371 
tympani, 1161 
teres major, 474 
minor, 473 
of thigh, 512 
of thoracic region, anterior, 
463 
lateral, 468 
of thorax, 424 
thyro-arytenoid, 1373 
-epiglottideus, 1373 
-hyoid, 392 
tibialis anticus, 532 
posticus, 538 INDEX 
1579 
Muscle or muscles, of tibio- 
fibular region, 531 
of tongue, 400 
extrinsic, 398 
intrinsic, 391 
trachelo-mastoid, 419 
tragicus, 1147 
transversalis abdominis, 442, 
1516 
cervicis, 419 
colli, 419 
trans versus auriculae, 1147 
menti, 378 
perinei superficialis, in fe- 
male, 460 
in male, 457 
trapezius, 411 
triangular, 362 
triangularis menti, 378 
sterni, 425 
triceps, 477 
extensor cubiti, 477 
of trunk, 410 
of ulnar region, 498 
unstriated, 361 
unstriped, 361 
of upper extremity, 462 
of ureters, 1437 
vastus extern us, 517 
internus, 517 
of vertebral region, anterior, 
406 
lateral, 408 
voluntary, 361 
zygomaticus major, 377 
minor, 377 
Muscular coat of anal canal, 1317 
of bladder, 1437 
of duodenum, 1288 
of intestine, large, 1317 
small, 1290 
of cesophagus, 1228 
of rectum, 1317 
of stomach, 1273 
of vermiform appendix, 1305 
portion of urethra, 1442 
structure of heart, 575 
substance of tongue, 398 
Musculi papillares of ventricle, 
left, 571 
right, 570 
pectinati of auricle, left, 511 
right, 566 
pubo-vesicalis, 1437 
Musculo-cutaneous nerve, 985, 
1017 
-phrenic artery, 644 
-spiral groove, 179 
nerve, 989 
branches of, 990 
Myelencephalon, 938 
Mylo-hyoid artery, 614 
muscle, 394 
ridge, 123 
-hyoidean groove, 124 
Myocardium, 574 
Myrtiform fossa, 106 
N 
Naboth, ovules of, 1492 
Nails, 1185 
body of, 1185 
edge of, 1185 
lunula of, 1185 
matrix of, 1185 
ridges of, 1185 
ungual fold of, 1185 
wall of, 1185 
Nares, anterior, 142, 1098 
Nares, posterior, 142, 1098 
septum of, 142 
Nasal angle, 105 
artery from internal maxil- 
lary, 616 
from ophthalmic, 625 
of septum, 607 
transverse, 625 
bones, 104 
articulations of, 105 
attachment of muscles to, 
105 
borders of, 105 
development of, 105 
surfaces of, 105 
cartilages, 1096 
cavity, 142 
crest, 111, 116 
duct, 1142 
fossae, 142, 1098 
arteries of, 1101 
atrium of, 1100 
inner wall of, 1100 
lymphatics of, 1102 
mucous membrane of, 1100 
nerves of, 1102 
outer wall of, 1099 
surgical anatomy of, 1102 
veins of, 1101 
groove, 105 
nerve, 1030 
branches of, 1030 
notch, 80 
portion of pharynx, 1221 
process, 80 
of superior maxillary, 109 
region, muscles of, 375 
slit, 143 
spine, 80 
anterior, 111, 139, 143 
posterior, 116, 135, 143 
venous arch, 725 
Nasion, 80, 139 
Nasmyth's membrane, 1204 
Naso-frontal vein, 740 
-labial ridge, 377 
-labialis muscle, 380 
-maxillary suture, 139 
-palatine artery, 616 
canal, 121 
groove, 121 
nerve, 1036 
-pharynx, 1221 
Navicular bone, 246 
articulations of, 247 
attachment of muscles to, 
247 
surfaces of, 246 
tuberosity of, 246 
Neck, arteries of, 595 
fasciae of, 385 
lymphatic glands of, 779, 784 
vessels of, 787 
muscles of, 385 
triangles of, posterior, 618 
surgical anatomy of, 616 
veins of, 724, 728 
Nelaton's line, 229 
Nerve or nerves, abducent, 1043 
ansa hypoglossi, 1066 
of arm, 977 
Arnold's, 1060 
of arteries, 586 
articular, of anterior tibial, 
1017 
of auriculo-temporal, 1038 
of great sciatic, 1013 
of internal plantar, 1015 
popliteal, 1014 
of peroneal, 1016 
of posterior tibial, 1015 
Nerve or nerves, articular, of 
ulnar, 988 
auditory, 1050 
auricular, anterior, 1038 
of pneumogastric, 1060 
posterior, 1047 
auriculo-temporal, 1037 
of bones, 41 
buccal, 1037 
from facial, 1049 
buccinator, 1037 
calcaneal, external, 1014 
internal, 1015 
calcaneo-plantar, 1015 
cardiac, cervical, 1061 
great, 1077 
inferior, 1077 
middle, 1077 
minor, 1077 
superior, 1076 
thoracic, 1061 
cardio-motor, 1071 
carotico-tympanic, 1073 
carotid, 1057 
cavernous, large, 1086 
small, 1086 * 
-cells, 818 
axone of, 821 
dendrites of, 821 
development of, 823 
cerebral, 1019 
cervical, 968, 1049 
superficial, 973 
cervico-facial, 1049 
chorda tympani, 1038, 1047 
ciliary, long, 1030 
short, 1031 
circumflex, 984 
coccygeal, 1006 
cochlear, 1053 
communicantes hypoglossi, 974 
communicating, fibulae, 1014 
tibial, 1014 
of Cotunnius, 1036 
cranial, 1019 
first, 880 
crural, anterior, 1004 
accessory of Winslow, 
1004 ' 
cutaneous, of abdomen, 996 
external, 985, 1003 
internal, 986, 1004 
of internal plantar, 1015 
middle, 1004 
of musculo-cutaneous, 1017 
-spiral, 991 
of obturator, 1003 
palmar, 986 
of perineal, 1013 
of peroneal, 1016 
of small sciatic, femoral, 
1011 
gluteal, 1011 
perineal, 1011 
of supraorbital, 1030 
of thorax, 995 
of ulnar, 988 
dorsal, 989 
palmar, 988 
dental, anterior superior, 1033 
inferior, 1039 
middle superior, 1033 
posterior superior, 1032 
descendens hypoglossi, 1066 
noni, 1066 
digastric, from facial, 1048 
digital, foot, 1015 
hand, 987 
dorsal, 993 
of clitoris, 1013 
of penis, 1013 1580 
INDEX 
Nerve or nerves,dorsi-lumbar,996 
of dura mater of brain, 849 
eighth, 1050 
eleventh, 1063 
-endings, Ruffini's, 828 
-epithelium cells, 830 
of eyeball, 1021 
facial, 1044 
-fibre, axis-cylinder of, 822 
-fibres, 822 
development of, 823 
medullated, 822 
non-medullated, 823 
of retina, 1122 
fifth, 1026 
first, 1019 
of foot, 1015 
fourth, 1025 
frontal, 1030 
ganglia of, 831 
gastric, 1061 
genito-crural, 1000 
glosso-pharyngeal, 1054 
gluteal, inferior, 1011 
superior, 1010 
gustatory, 1038 
haemorrhoidal, inferior, 1011 
of heart, 577 
hypogastric, 999 
hypoglossal, 1064 
iliac, 999 
ilio-hypogastric, 999 
-inguinal, 999 
incisor, 1039 
inframandibular, 1049 
inframaxillary, 1049 
infraorbital, 1049 
infratrochlear, 1031 
intercostal, 993 
intercosto-humeral, 995 
interosseous, anterior, 987 
of anterior tibial, 1017 
posterior, 991 
Jacobson's, 1056 
jugular, 1073 
labial, 1034 
of labyrinth, 1176 
lachrymal, 1028 
of Lancisi, 887 
laryngeal, inferior, of pneumo- 
gastric, 1060 
superior, 1060 
external, 1060 
internal, 1060 
lingual of fifth, 1038, 
of glosso-pharyngeal, 1057 
lumbar, 997 
malar, 1049 
of superior maxillary, 1032 
mandibular, 1036 
masseteric, 1037 
mastoid, 973 
maxillary, inferior, 1036 
superior, 1031 
median, 986 
meningeal, 1032 
from hypoglossal, 1066 
of internal maxillary, 1036 
of pneumogastric, 1059 
mental, 1039 
motor oculi, 1024 
muscular, of anterior tibial, 
1017 
of external plantar, 1016 
of great sciatic, 1013 
of hypoglossal, 1066 
of internal plantar, 1015 
popliteal, 1014 
of musculo-cutaneous, 1017 
-spiral, 990 
of perineal, 1013 
Nerve or nerves, muscular, of 
posterior tibial, 1014 
of sciatic plexus, 1010 
of ulnar, 988 
musculo-cutaneous, 985, 1017 
-spiral, 989 
mylo-hyoid, 1039 
nasal, 1030 
from Meckel's ganglion, 1034 
ganglionic branch of, 1030 
naso-palatine, 1036 
ninth, 1054 
obturator, 1003 
accessory, 1004 
occipital, from facial, 1048 
great, 969 
small, 972 
cesophageal, 1061 
olfactory, 880, 1019 
ophthalmic, 1028 
optic, 1021 
orbital, of superior maxillary, 
1032 
origin of, 826 
palatine, anterior, 1035 
external, 1035 
large, 1035 
middle, 1035 
posterior, 1035 
small, 1035 
palmar, of ulnar, deep, 989 
superficial, 989 
palpebral, 1034 
parotid, 1038 
-paths, 959 
auditory, 1053 
cochlear, 1053 
gustatory, 1057 
vestibular, 1054 
perforating, of Casserius, 985 
of pericardium, 561 
pericranial, 1030 
perineal, 1013 
peroneal, 1016 
petrosal, deep, 1073 
great deep, 1034 
superficial, 1034 
large deep, 1034, 1073 
superficial, 1034 
pharyngeal, 1036, 1057, 1060 
phrenic, 974 
of pia mater of brain, 856 
plantar, external, 1016 
internal, 1015 
plexus of, abdominal aortic, 
1085 
annular, 1111 
brachial, 977 
cardiac, 1081 
carotid, internal, 1073 
cavernous, 1073 
cervical, 972 
cceliac, 1061, 1084 
colic, left, 1085 
coronary, 1081, 1085 
cystic, 1085 
of dental, superior. 1033 
epigastric, 1083 
fundamental, 1111 
gastric, 1085 
gastro-duodenal, 1085 
-epiploic, 1085 
left, 1085 
haemorrhoid al, inferior, 1086 
superior, 1085 
hepatic, 1085 
hypogastric, 1085 
infraorbital, 1049 
intra-epithelial, 1111 
lumbar, 998 
mesenteric, inferior, 1085 
Nerve or nerves, plexus of, mes- 
enteric, superior, 1085 
oesophageal, 1059, 1061, 
1082 
ovarian, 1084 
pancreatic, 1085 
patellar, 1004 
pelvic, 1086 
pharyngeal, 1057 
phrenic, 1084 
prostatic, 1086 
pudendal, 1009 
pudic, 1009 
pulmonary, 1081 
anterior, 1059, 1061 
posterior, 1059, 1061 
pyloric, 1085 
renal, 1061, 1084 
sacral, 1009, 1086 
sciatic, 1009 
sigmoid, 1085 
solar, 1083 
spermatic, 1084 
splenic, 1061, 1085 
subclavian, 1077 
subepithelial, 1111 
suprarenal, 1084 
thoracic aortic, 1079' 
tympanic, 1057 
uterine, 1086 
utero-vaginal, 1086 
vaginal, 1086 
vertebral, 1077 
vesical, 1086 
pneumogastric, 1057 
popliteal, external, 1016 
internal, 1014 
portio dura, 1044 
mollis, 1045 
pterygoid, external, 1037 
internal, 1037 
pterygo-palatine, 1036 
pudendal, inferior, 1011 
pudic, 1011 
pulmonary, anterior, 1061 
posterior, 1061 
radial, 991 
recurrent, of internal maxil- 
lary, 1036 
laryngeal, of pneumogastric, 
1060 
respiratory, of Bell, external,. 
983 
internal, 974 
sacral, 1006 
saphenous, external, 1014 
internal, 1005 
long, 1005 
short, 1014 
scapular, posterior, 982 
of Scarpa, 1036 
sciatic, great, 1013 
small, 1011 
scrotal, long, 1011 
second, 1021 
seventh, 1044 
sixth, 1043 
spheno-palatine, 1032 
sphenoidal, 1039 
spinal, 964 
accessory, 1063 
-spindles, 829 
splanchnic, 1079 
renal, 1079 
stylo-hyoid, 1048 
subcutaneous mala*, 1032- 
suboccipital, 968 
subscapular, 984 
superficialis colli, 973 
supra-acromial, 974 
supraclavicular, 974 INDEX 
1581 
Nerve or nerves, supramandib- 
ular, 1049 
supramaxillary, 1049 
supraorbital, 1030 
suprascapular, 983 
suprasternal, 974 
supratrochlear, 1030 
sural, 1016 
sympathetic, 1066 
temporal, of auriculo-tempo- 
ral, 1038 
deep, 1037 
from facial, 1049 
of superior maxillary, 1032 
temporo-malar, 1032 
tenth, 1057 
termination of, 826 
peripheral, 826 
third, 1024 
thoracic, 993 
anterior, 984 
long, 983 
posterior, 983 
thyro-hyoid, 1066 
thyroid, 1077 
tibial, 1014 
anterior, 1016 
posterior, 1014 
tonsillar, 1057 
trifacial, 1026 
trigeminal, 1026 
trochlear, 1025 
twelfth, 1064 
tympanic, 1056 
from facial, 1047 
ulnar, 988 
-unit, 818 
vagus, 1057 
vasomotor, 1071 
vestibular, 1053 
Vidian, 1034 
Nervi nervorum, 825 
Nervous papilla1, 1181 
system, 817 
cerebro-spinal, structure of, 
817 
tissue, chemical composition 
of, 824 
cutaneous patellae, 1005 
superficialis cordis, 1076 
Neumann, dentinal sheath of, 
1203 
Neural arch, 34 
canal, 857 
tube, 857 
Neurenteric canal, 1242 
Neurilemma of cord, 822 
Neuroblasts, 823 
Neuro-central suture, 59 
-muscular spindles, 829 
-tendinous spindles, 829 
Neuroglia of cord, 840 
Neurokeratin, 823 
Neurones, 818 
of Cajal, 919 
cell-bodies of, 818 
theory of, 821 
Nexal root of eighth nerve, 1050 
Nidus avis of cerebellum, 931 
Ninth nerve, 1054 
surgical anatomy of, 1057 
Nipple, 1504 
structure of, 1505 
Nissl's bodies, 820 
Nodal point, 1106 
Nodules of cerebellum, 930 
Non-medullated nerve-fibres, 823 
Nose, 1095 
aperture of cartilage of, 1097 
arteries of, 1098 
cartilage of, 1096 
Nose, dorsum of, 1096 
fossae of, 142, 1098 
integument of, 1097 
interior of, lymphatic vessels 
of, 782 
lymphatics of, 1098 
meatus of, inferior, 145 
middle, 145 
superior, 101, 144 
mucous membrane of, 1098 
muscles of, 1097 
nerves of, 1098 
outer, 1096 
septum of, 142 
cartilage of, triangular, 1097 
structure of, 1096 
veins of, 1098 
Notch cerebellar, anterior, 926 
posterior, 926 
cotyloid, 213 
ethmoidal, 82 
ilio-sciatic, 210 
ihtercondyloid, 225 
intervertebral, 49 
lachrymal, 107 
nasal, 80 
popliteal, 234 
pre-sternal, 157 
pre-occipital, 869 
pterygoid, 96 
of Rivinus, 1151 
sacro-sciatic, 217 
great, 210 
lesser, 211 
scapular, great, 173 
sigmoid, 125 
spheno-palatine, 118 
supraorbital, 80, 140 
suprascapular, 174 
suprasternal, 409 
thyroid, 1362 
Nuchal line, inferior, 72 
superior, 72 
plane, 72 
Nuck, canal of, 1462, 1501 
Nucleated sheath of Schwann, 
822 
Nuclei, auditory, 950 
of auditory nerve, 925 
of fifth nerve, 925 
of glosso-pharyngeal nerve, 950 
of optic thalamus, 904 
of vagus nerve, 950 
Nucleus, accessory, of eighth 
nerve, 1051 
amygdaloid, 891 
ambiguus, 950, 1056 
of Bechterew, 926, 1050 
caudate, 891 
cuneate, accessory, 948 
of Deiters, 926, 1050 
emboliformis, 938 
of facial nerve, 925 
fasciculi gracilis, 941 
fastigii, 938 
globosus, 938 
hypoglossal, 949 
inferior central, 949 
lentis, 1132 
lenticular, 890 
of Luys, 908, 910 
of olivary body, 951 
accessory, 951 
superior, 925 
of optic thalamus, 904 
of sixth nerve, 925 
of spinal accessory nerve, 950 
of Stilling, red, 938 
of tegmentum, red, 908 
vagi, 1057 
Nuel,. space of, 1175 
Nuhn and Blandin, glands of, 
1091 
Nutrient artery of femur, 707 
of fibula, 718 
of humerus, 656 
of tibia, 719 
Nymphse, 1478 
0 
Obelion, 129 
Obex, 944 
Oblique diameter of pelvis, 217 
fibres of cord, 841 
inguinal hernia, 1517, 1520 
complete, 1521 
incomplete, 1521 
ligament, 314 
line of clavicle, 168 
of fibula, 237 
of radius, 190 
of tibia, 235 
muscles, ascending, 437 
aponeurosis of, 439 
descending, 433 
external, 433 
aponeurosis of, 434 
internal, 437, 1516 
aponeurosis of, 439 
dissection of, 437 
ridges of scapula, 171 
of trapezium, 198 
of ulna, 188 
sacro-iliac ligament, 292 
sinus of pericardium, 560 
vein of Marshall, 771 
Obliquus auriculae muscle, 1147 
capitis inferior muscle, 422 
superior muscle, 422 
oculi muscle, inferior, 374 
superior, 373 
Obstetric perinaeum, 1478 
Obturator artery, 688 
peculiarities of, 689 
bursa, 331 
canal, 525 
crest, 213 
externus muscle, 528 
fascia, 1546 
foramen, 214 
groove, 211, 213 
internus muscle, 525 
bursa of, 525 
ligament, 296 
membrane, 525 
nerve, 1003 
accessory, 1004 
vein, 761 
Occipital artery, 608, 640 
branches of, 609 
bone, 71 
angles of, 75 
articulations of, 76 
attachment of muscles to, 76 
borders of, 75 
development of, 75 
structure of, 75 
surfaces of, 71 
convolution, inferior, 877 
middle, 877 
superior, 877 
crest, external, 72, 136 
internal, 74, 133 
diploic vein, 734 
fossae, inferior, 133 
groove, 86 
horn of lateral ventricle, 889 
lobe, 876 
gray matter of, 921 
lymphatic glands, 780 1582 
INDEX 
Occipital nerve, branch of facial, 
1048 
great, 969 
small, 972 
protuberance, external, 71, 136 
internal, 73 
sinus, 739 
sulci, 868, 876 
triangle, 618 
vein, 727 
Occipitalis muscle, 368 
Occipito-atlantal ligament, ante- 
rior, 276 
posterior, 276 
-axial ligament, posterior, 278 
-frontal fasciculus, 918 
-frontalis, muscle, 367 
surgical anatomy of, 368 
-parietal suture, 128 
-temporal convolution, 878 
gyrus, 877 
sulcus, 870 
Occiput, arteries of, 608 
Odontoblasts, 1206 
of Waldeyer, 1201 
Odontoclasts, 1209 
Odontoid ligaments, lateral, 278 
middle, 52, 279 
process of axis, 52 
(Esophageal arteries, 641, 666 
nerves, 1061 
opening of diaphragm, 430 
of stomach, 1270 
plexus, 1059, 1061, 1082 
veins, 751 
(Esophagus, 1225 
abdominal portion, 1226 
anomalies of, 1228 
areolar coat of, 1229 
arteries of, 1229 
cervical portion, 1226 
diaphragmatic portion, 1226 
innervation of, 1230 
lymphatics of, 815, 1230 
movements of, 1230 
mucous coat of, 1229 
muscular coats of, 1228 
nerves of, 1230 
relations of, 1227 
structure of, 1228 
submucous coat of, 1229 
surgical anatomy of, 1230 
thoracic portion, 1226 
veins of, 1229 
Olecranon bursa, 311 
subcutaneous, 477 
fossa, 181 
process, 186 
Olfactory bulb, 880, 1019 
gray matter of, 921 
cells, 1101 
fasciculus, 895 
foramina, 143 
hair, 1101 
lobe, 880 
anterior, 880 
posterior, 881 
nerve, 880, 1019 
surgical anatomy of, 1021 
path, 1020 
sulcus, 870, 874 
tract, 880, 1019 
tubercle, 881, 1019 
Olivary body of medulla oblon- 
gata, 941 
corpus of, 951 
nucleus of, 951 
peduncles of, 951 
bundle of cord, 843 
eminence, 93 
fasciculus, 910 
Olivary nucleus superior, 925 
process, 93, 131 
Omenta, 1254 
Omental band, 1317 
tuberosity, 1329 
Omentum, development of, 1238 
gastro-colic, 1256 
-hepatic, 1254 
-splenic, 1256 
great, 1256 
lesser, 1254 
Omo-hyoid muscle, 393 
Opercula of insula, 878 
Operculum, frontal, 866, 874 
fronto-parietal, 866, 874 
orbital, 866, 874 
Ophryon, 80 
Ophthalmic artery, 622 
branches of, 622 
ganglion, 1031 
nerve, 1028 
branches of, 1028 
veins, 740 
inferior, 741 
superior, 740 
Opisthotonic portion of temporal 
bone, 91 
Opponens minimi digiti muscle, 
foot, 547 
hand, 498 
pollicis muscle, 496 
Optic axis, 1106 
chiasma, 882 
commissure, 131, 882, 1021 
inter-cerebral fibres of, 1021 
cup, 1121 
disk, 1121 
foramen, 93, 96, 131, 142 
groove, 93, 130, 131 
lobes, 911 
nerve, 1021 
surgical anatomy of, 1022 
papilla, 1121 
path, 1022 
radiations, 905 
recess, 902 
thalamus, 903 
connections of, 905 
nuclei of, 904 
stalk of, 905 
tubercle of, 904 
tract, 884, 1021 
Ora serrata, 1120 
Oral cavity, 1193 
portion of pharynx, 1221 
of tongue, 1087 
Orbicular bone, 1159 
ligament, 314 
muscles, 363 
Orbicularis oris muscle, 378 
palpebrarum muscle, 370 
external portion of, 370 
internal portion of, 370 
orbital portion of, 370 
palpebral portion of, 370 
Orbiculus ciliaris, 1115 
Orbit, 140 
arteries of, 623 
fascia' of, 374 
margin of, 106 
muscles of, 374 
Orbital artery, 611 
internal, 627 
branch of facial nerve, 1032 
cavities, 140 
convolution, anterior, 874 
internal, 873 
posterior, 874 
fascia, 375 
fissure, 96 
foramina, 95 
Orbital fossae, 140, 143 
lobe, 874 
muscle, 374 
nerve, 1032 
operculum, 866, 874 
plates, 81 
process of malar, 114 
of palate bone, 118 
region, muscles of, 372 
action of, 374 
dissection of, 372 
surgical anatomy of, 375 
septum, 1139 
sinus, 118 
sulcus, 870, 874 
vein, 727 
Orbito-palpebral sulcus, inferior, 
1137 
superior, 1137 
-tarsal ligament, 1139 
Orbits, 140 
Organ of Corti, 1173 
of Jacobson, 1100 
Organs of digestion, 1193 
of generation, female, 1477 
male, 1447 
of Giraldes, 1473 
of Golgi, 829 
of respiration, 1361 
of Rosenmuller, 1499 
of special sense, 1087 
of voice, 1361 
Orifice, mitral, 568 
of prostatic ducts, 1442 
tricuspid, 567 
of ureters, 1438 
Os acetabulum, 213 
external, 1489 
incae, 76 
innominatum, 207 
articulations of, 215 
attachment of muscles to, 
215 
development of, 214 
ilium, 207 
ischion, 210 
pubis, 212 
structure of, 214 
internal, 1488 
magnum of carpus, 199 
articulations of, 199 
attachment of muscles to, 
199 
surfaces of, 199 
planum of ethmoid, 100 
trigonum, 245 
uteri, 1489 
Ossa pubis, articulations of, 296 
angle of, 212 
unguis, 113 
Osseous labyrinth, 1164 
portion of Eustachian tube, 
1154 
of external auditory meatus, 
1149 
Ossicles of tympanum, 1158 
articulations of, 1160 
ligaments of, 1160 
movements of, 1161 
Ossification of bone, 42 
centre of, 44 
intracartilaginous, 43 
intramembranous, 43 
of spine, 60 
Osteo-dentine of Owen, 1204 
Osteoclasts, 36 
Osteology, 33 
Ostium abdominale of Fallopian 
tube, 1497 
Otic ganglion, 1039 
branches of, 1039 INDEX 
1583 
Otokonien, 1171 
Otolith, 1169 
membrane, 1172 
Outlet of pelvis, 217 
Ova, primordial, 1502 
Ovarian arteries, 680 
bursa, 1490 
plexus, 1084 
veins, 766 
Ovario-pelvic fold, 1500 
Ovary, 1499 
arteries of, 1503 
at different ages, 1501 
connections of, 1500 
descent of, 1501 
fimbria of, 1499 
hilum of, 1500 
lymphatics of, 1503 
lymphatic vessels of, 804 
nerves of, 1503 
serous covering of, 1501 
stroma of, 1501 
structure of, 1501 
supports of, 1500 
surgical anatomy of, 1503 
veins of, 1503 
Ovicapsule of Graafian follicles, 
1502 
Ovules of Naboth, 1492 
Ovum, discharge of, 1503 
Oxyntic cells, 1277 
glands, 1277 
P 
Pacchionian depressions, 78 
glands, 737, 854 
Pacinian corpuscles, 828 
Pads of adipose tissue, 263 
corpus callosum, 886 
Palatal region, muscles of, 403 
dissection of, 403 
surgical anatomy of, 406 
Palate, 1210 
bone, 115 
articulations of, 119 
attachment of muscles to, 
119 
development of, 119 
horizontal plate of, 116 
borders of, 116 
surfaces of, 116 
perpendicular plate of, 117 
borders of, 117 
surfaces of, 117 
processes of, 118 
tuberosity of, 117, 135 
vertical plate of, 117 
borders of, 117 
surfaces of, 117 
hard, 1210 
muscles of, 403 
soft, 1211 
surgical anatomy of, 1224 
vail of, 1211 
Palatine aponeurosis, 404 
artery, ascending, 606 
descending, 615 
inferior, 606 
posterior, 615 
surgical anatomy of, 615 
canal, anterior, 143 
posterior, 107, 116 
accessory, 116, 135 
foramen, great, 116 
posterior, 135 
fossa, anterior, 110, 133 
glands, 1211 
nerve, anterior, 1035 
external, 1035 
Palatine nerve, large, 1035 
middle 1035 
posterior, 1035 
small, 1035 
process of superior maxillary, 
120 
spine, 116 
Palato-glossus muscle, 398, 405 
-maxillary canal, 107 
-pharyngeus muscle, 405 
Palmar arch, deep, 658 
superficial, 664 
surface marking of, 665 
surgical anatomy < f, 635 
cutaneous nerve, 987 
fascia, deep, 493 
surgical anatomy of, 494 
interosseous arteries, 660 
plexus of nerves, 745 
recurrent arteries, 660 
region, middle, muscles of, 499 
veins, 747 
Palmaris brevis muscle, 498 
longus muscle, 480 
Palpebral arteries, external, 623 
internal, 623 
cartilages or plates, 1139 
fasciae, 1139 
ligaments, 1139 
nerves, 1034 
portion of conjunctiva, 1140 
region, muscles of, 370 
dissection of, 370 
Pampiniform plexus of veins, 765 
Pancreas, 1348 
arteries of, 1352 
body of, 1350 
borders of, 1350 
development of, 1244 
dissection of, 1348 
head of, 1348 
lymphatic vessels of, 807 
lymphatics of, 1352 
neck of, 1350 
nerves of, 1353 
peritoneal relations of, 1351 
structure of, 1352 
surface form of, 1353 
surfaces of, 1350 
surgical anatomy of, 1353 
tail of, 1350 
veins of, 1352 
Pancreatic area of kidney, 1414 
artery, 674 
duct, 1351 
juice, 1353 
plexus of nerves, 1085 
of veins, 768 
Pancreatica magna artery, 674 
Pancreatico-duodenal artery, 
inferior, 675 
superior, 674 
plexus of nerves, 1085 
vein, 768 
Papilla, bile, 1288 
dentine, 1205 
lachrymal, 1142 
spiralis, 1173 
Papillae circumvallate, 1089 
conical, 1090 
filiform, 1090 
fungiform, 1090 
maximae, 1089 
mediae, 1090 
minimae, 1090 
of tongue, 1089 
simple, 1090 
structure of, 1090 
Papillary layer of skin, 1187 
Paracentral lobule, 875 
Paraduodenal fossa, 1262 
Paramastoid process, 73 
Paramedialis sulcus, 868 
Parametrium, 1489 
Paramammary gland, 813 
Paranucleus, 1352 
Parathyroids, 1406 
structure of, 1406 
Parenchyma of lungs, 1395 
of testicle, 1471 
Paries carotica, 1153 
jugularis, 1151 
labyrinthica. 1152 
mastoidea, 1152 
tegmentalis, 1151 
Parietal artery, 611 
arteries, ascending, 628 
bone, 76 
articulations of, 79 
attachment of muscles to, 
79 
development of, 78 
surfaces of, 76 
borders of, 78 
cells of gastric glands, 1277 
convolution, ascending, 876 
inferior, 876 
superior, 876 
diploic vein, external, 734 
eminence, 76 
foramen, 76 
layer of pleura, 1385 
lobe, 875 
lymphatics, 810 
peritoneum, 1247 
portion of tunica vaginalis, 
1470 
surface of liver, 1330 
of stomach, 1269 
Parieto-colic fold, external, 1263 
internal, 1264 
-occipital sulcus, 867 
externa], 867 
internal, 867, 870 
-sphenoidal artery, 628 
-temporal artery, 628 
Paro-ophoron, 1499 
Parotid capsule, 1216 
duct, 1215 
structure of, 1216 
surface form of, 1215 
fascia, 388, 1215 
gland, 1214 
accessory, 1215 
arteries of, 1216 
duct of, 1215 
lymph, 1215 
lymphatics of, 1216 
nerves of, 1216 
veins of, 1216 
lymphatic glands, 781 
deep, 782 
superficial, 781 
nerves, 1038 
recess, 1215 
Paratideo-masseterica fascia, 388 
Parovarium, 1499 
Pars ciliaris retinae, 1115, 1120 
intermedia of Wrisberg, 1045 
iridica retinae, 1120 
Patella, 230 
apex of, 231 
articulations of, 231 
attachment of muscles to, 231 
borders of, 231 
development of, 231 
ligaments of, 335 
structure of, 231 
surfaces of, 231 
form of, 231 
surgical anatomy of, 231 
Patellar bursa, deep, 518 1584 
INDEX 
Patellar plexus, 1004 
Path of light stimuli, 1127 
Paths, nerve, auditory, 1053 
cochlear, 1053 
gustatory, 1057 
vestibular, 1054 
olfactory, 1020 
optic, 1022 
Pecquet, reservoir of, 775 
Pecten ossis pubis, 212 
Pectineus muscle, 519 
nerve to, 1005 
Pectoral fascia, deep, 464 
gland, 790 
intercostal nerve, 995 
region, dissection of, 463 
ridge, 179 
Pectoralis muscle, major, 464 
minor, 468 
Peduncles of cerebellum, 932 
inferior, 935 
middle, 922, 934 
superior, 910, 932, 943 
cerebral, 906 
of cerebrum, 882, 884 
of corpus callosum, 882, 886 
<of flocculus, 931 
<of mammillary body, 883 
of olive, 951 
of perineal gland, 895, 906 
Peduncular fibres of cerebellum, 
932 
of cerebrum, 914 
Pelvic colon, 1311 
fascia, 1544 
girdle, 207 
ligament, transverse, 459 
plexus, 1086 
portion of gangliated cord, 1080 
Pelvis, 215 
axes of, 218 
brim of, 217 
cavity of, 217, 1431 
boundaries of, 1431 
contents of, 1431 
diameters of, 217 
diaphragm of, 1231 
differences between male and 
female, 219 
false, 215 
of kidney, 1415 
lower circumference of, 217 
lymphatic vessels of, 801 
lymphatics of, 797 
muscles of, 449 
outlet of, 217 
position of, 218 
surface form of, 220 
surgical anatomy of, 220 
true, 216 
inlet of, 217 
superior circumference of, 
217 
veins of, 755 
Pendulous portion of urethra, 
1443 
Penile portion of urethra, 1443 
Penis, 1453 
arteries of, 1459 
dorsal, 692 
body of, 1455 
corpora cavernosa of, 1455 
corpus spongiosum, 1458 
crura of, 1454 
dorsum of, 1455 
fraenum of, 1455 
ligaments of, 1459 
lymphatics of, 1459 
vessels of, superficial, 801 
nerves of, 1013, 1460 
dorsal, 1013 
Penis, prepuce of, 1455 
root of, 1454 
septum of, 1457 
structure of, 1455 
surgical anatomy of, 1460 
veins of, 1459 
dorsal, deep, 762 
superficial, 762 
Penniform muscles, 363 
Peptic cells of glands, 1277 
glands, 1277 
Perforating arteries, anterior, 
644 
of hand, 660 
of thigh, 706 
cutaneous nerve, 1011 
nerve of Casserius, 985 
Pericaecal folds, 1262 
fossae, 1262 
Pericardiac arteries, 644, 666 
Pericardial pleura, 1385 
sac, 1236 
Pericardiothoracic cavity, 1236 
Pericardium, 557 
arteries of, 561 
fibrous layer of, 558 
nerves of, 561 
serous, 560 
sinus of, oblique, 560 
transverse, 560 
structure of, 558 
surgical anatomy of, 561 
vestigial fold of, 561 
Pericementum, 1196 
Perichondrium, 260 
Perichoroidal space, 1108 
Pericranial nerves, 1030 
Perilymph, 1164 
space, 1164 
Perimysium, external, 361 
internal, 361 
Perineal artery, superficial, 690 
transverse, 691 
body, 1314, 1484, 1543 
cutaneous nerve, 1011 
fascia, deep, 1538 
ligament, transverse, 459 
nerve, 1013 
Perineum, 1314, 1484 
dissection of, 1535 
in female, 1542 
muscles of, 460 
lymphatic vessels of, super- 
ficial, 801 
in male, 1537 
central tendinous point of, 
1537 
fasciae of, 455 
muscles of, 455 
obstetric, 1478 
surgical anatomy of, 1535 
Perineurium, 825 
Periosteum, 37 
^dental, 1204 
Peripheral branches of lumbar 
portion of gangliated cord, 
1080 
of middle cervical ganglion, 
1077 
of pelvic portion of gangli- 
ated cord, 1080 
of sacral portion of gangli- 
ated cord, 1080 
of superior cervical gan- 
glion, 1073 
of thoracic portion of gan- 
gliated cord, 1079 
terminations of nerves, 826 
Peritoneal coat of duodenum, 
1288 
of stomach, 1273 
Peritoneal relations of pancreas, 
1351 
Perisclerotic lymph-space, 1103 
Peritoneum, 1245 
development of, 1235, 1242 
ligaments of, 1254 
lymphatic vessels of, 802 
surgical anatomy of, 802 
mesenteries of, 1257 
omenta of, 1254 
parietal, 1247 
structure of, 1245 
surgical anatomy of, 1264 
visceral, 1247 
Peritracheo-bronchial glands, 
812 
Perivascular lymph-spaces, 772 
Permanent teeth, 1196 
development of, 1208 
eruption of, 1209 
superadded, 1208 
Peroneal artery, 717 
anterior, 718 
branches of, 718 
peculiarities of, 718 
posterior, 718 
relations of, 718 
groove, 245 
nerve, 1016 
spine, 243 
tubercle, 243 
vein, 578 
Peroneus brevis muscle, 540 
longus muscle, 539 
tertius muscle, 534 
Perpe'ndicular line of ulna, 188 
plate of ethmoid, 100 
of palate bone, 117 
Pes accessorius, 890 
anserinus, 1045 
of crus cerebri, 907 
hippocampi, 890 
Petit, canal of, 1130 
triangle of, 435 
Petro-mastoid portion of tem- 
poral bone, 91 
-occipital fissure, 128 
suture, 75, 133 
-sphenoidal fissure, 128 
suture, 136 
-squamous sinus, 739 
suture, 88 
-tympanic fissure, 84, 1152 
Petrosal nerve, deep, 1073 
great deep, 1034 
superficial, 1034 
large deep, 1034, 1073 
superficial, 1034 
process, 93 
sinus, inferior, 742 
superior, 742 
Petrous, ganglion, 1056 
branches of, 1056 
portion of internal carotid 
artery, 620 
of temporal bone, 136 
Peyer's glands, 1296 
patches, 1296 
Phalanges of foot, 252 
articulations of, 252, 359 
attachment of muscles of, 
252 
development of, 254 
of hand, 204 
articulations of, 204, 325 
attachment of muscles to, 
204 
development of, 206 
ligaments of, 325 
Pharyngeal aponeurosis, 402, 
1223 INDEX 
1585 
Pharyngeal artery, ascending, 
610 
branches of, 610 
surgical anatomy of, 611 
branch of pneumogastric nerve 
1060 
bursa, 1224 
glands, 1222 
nerve, 1036, 1057 
plexus, 1057 
portion of tongue, 1087 
region, muscles of, 400 
dissection of, 400 
ring, lymphatic, 1224 
spine, 73, 135 
tonsil, 1221, 1224 
tubercle, 73 
veins, 730 
plexus of, 730 
Pharyngo-epiglottic fold, 1222 
-glossus muscle, 398 
Pharynx, 1220 
aponeurosis of, 1223 
arteries of, 610 
fibrous coat of, 1223 
isthmus of, 1221 
laryngeal part, 1222 
lymphatic vessels of, 782 
mucous coat of, 1223 
muscles of, 400 
nasal part, 1221 
oral part, 1221 
structure of, 1222 
surgical anatomy of, 1224 
vault of, 1221 
Philtrum, 380 
Phleboliths, 762 
Phrenic arteries, inferior, 680 
superior, 644 
ganglion, 1084 
hernia, 427 
nerve, 974 
plexus of nerves, 1084 
surface of spleen, 1354 
veins, 767 
Phrenico-costal sinus, 1386, 1414 
-pleural fascia, 1386 
Phreno-colic ligament, 1259 
-pericardial ligament, 559 
Physiological retina, 1120 
Pia mater of brain, 854 
arteries of, 856 
nerves of, 857 
veins of, 856 
of cord, 835 
structure of, 835 
Pigmentary layer of retina, 1127 
Pillars of fauces, 1211 
of fornix, anterior, 895 
posterior, 896 
Pineal body, 905 
gland, 905 
peduncles of, 895, 906 
structure of, 906 
recess, 903 
striae, 904 
Pinna of ear, 1144 
arteries of, 1147 
cartilage of, 1146 
integument of, 1146 
ligaments of, 1146 
lymphatics of, 1147 
muscles of, 1147 
nerves of, 1148 
structure of, 1146 
veins of, 1147 
Pisiform bone, 197 
articulations of, 197 
attachment of muscles to, 
197 
surfaces of, 197 
Pit of stomach, 165 
Pituitary body, 882 
structure of, 883 
fossa, 93 
membrane, 1100 
Pivot-joint, 265 
Plane, nuchal, 72 
Plantar arch, 719 
arteries, external, 720 
branches of, 720 
surface marking of, 720 
surgical anatomy of, 720 
internal, 719 
branches of, 720 
surface marking of, 720 
surgical anatomy of, 720 
fascia, 542 
surgical anatomy of, 543 
ligaments, long, 353 
superficial, 353 
short, 353 
nerves, external, 1016 
internal, 1015 
region, muscles of, 544 
dissection of, 544, 
veins, 758 
Plantaris muscle, 536 
Planum temporale, 76 
Plate, cribriform of ethmoid, 99 
horizontal, of palate bone, 116 
perpendicular, of ethmoid, 100 
of palate bone, 117 
pterygoid, external, 96 
internal, 96 
vertical, of ethmoid, 100 
of palate bone, 117 
Platysma myoides muscle, 386 
Pleurae, 1382 
arteries of, 1387 
cavity of, 1382 
cervical, 1385 
costal, 1385 
diaphragmatic, 1386 
dome of, 1385 
lymphatics of, 1387 
mediastinal, 1385 
nerves of, 1387 
parietal layer of, 1385 
pericardial, 1385 
pulmonary, 1385 
reflections of, 1384 
structure of, 1387 
surgical anatomy of, 1387 
veins of, 1387 
visceral layer of, 1382 
Pleural lymphatics, 815 
sacs, 1236 
Pleuroperitoneal cavity, 1236 
Plexus, Auerbachi, 1299 
interlobular, 1338 
of nerves, abdominal aortic, 
1080, 1085 
annular, 1111 
brachial, 977 
cardiac, 1081 
anterior, 1081 
deep, 1081 
great, 1081 
superficial, 1081 
carotid, internal, 1073 
cavernous, 1073 
cervical, 972 
posterior, 900 
choroid, 899 
cceliac, 1061, 1084 
colic, left, 1085 
coronary, 1085 
cystic, 1085 
dental, superior, 1033 
diaphragmatic, 1086 
epigastric, 1083 
Plexus of nerves, fundamental 
1111 
gastric, 1085 
gastro-duodenal, 1085 
-epiploic, 1085 
left, 1085 
haemorrhoidal, inferior, 108$ 
superior, 1085 
hepatic, 1085 
hypogastric, 1080, 1085 
infraorbital, 1049 
intra-epithelial, 1111 
lumbar, 998 
1 umbo-sacral, 998 
magnus profunda, 1081 
mesenteric, inferior, 1085 
superior, 1085 
oesophageal, 1059, 1061, 
1082 
ovarian, 1084 
pancreatic, 1085 
pancreatico-duodenal, IOS? 
patellar, 1004 
pelvic, 1086 
pharyngeal, 1057 
phrenic, 1084 
prostatic, 1086 
pudendal, 1009 
pudic, 1009 
pulmonary, 1059 
anterior, 1082 
posterior, 1081 
pyloric, 1085 
renal, 1061, 1084 
sacral, 1009, 1086 
sciatic, 1009 
sigmoid, 1085 
solar, 1083 
spermatic, 1084 
splenic, 1061, 1085 
subclavian, 1077 
subepithelial, 1111 
suprarenal, 1084 
thoracic aortic, 1079 
tympanic, 1057 
uterine, 1086 
utero-vaginal, 1086 
vaginal, 1086 
vertebral, 1077 
vesical, 1086 
of veins, infraclavicular, 792 
palmar, 745 
pharyngeal, 730 
prostatic, 761 
prostatico-vesical, 761 
pterygoid, 727 
spermatic, 765 
spinal, 753 
subpleural mediastinal, 644 
uterine, 763 
vaginal, 763 
venous, interspin jus, 732 
on thyroid body, 751 
vesical, inferior, 762 
superior, 761 
Plica, epigastrica, 1520 
fimbriata, 1087 
gubernatrix, 1461 
hypogastrica, 1519 
salpingopalatine, 1221 
salpingopharyngea, 1221 
semilunaris, 1140 
sublingualis, 1217 
triangularis, 1213 
urachi, 1519 
vascularis, 1461 
Pneumatic spaces, 1103 
Pneumogastric nerve, 1057 
ganglion of root of, 1059 
surgical anatomy of, 1062 
of trunk of, 1059 1586 
INDEX 
Polyaxonic cells, 821 
Polymazia, 1505 
Polythelia, 1505 
Pomum Adami, 1362 
Pons Tarini, 883 
Varolii, 883, 922 
base of, 922 
fibres of, 923 * 
gray matter of, 924 
structure of, 922 
surfaces of, 922 
veins of, 736 
Pontal arteries, 639 
Ponticulus, 1146 
of Arnold, 939 
Popliteal artery, 707 
branches of, 710 
contents of, 708 
peculiarities of, 709 
position of contained parts, 
708 
surface marking of, 709 
surgical anatomy of, 709 
groove, 226 
line, 235 
lymphatic glands, 795 
nerve, external, 1016 
internal, 1014 
branches, 1014 
notch, 234 
space, 707 
boundaries of, 707 
dissection of, 707 
vein, 758 
Popliteus muscle, 537 
Pore, gustatory, 1090 
Portal sinus, 769 
vein, 769 
system of, 768 
Portio-dura of seventh nerve, 
1044 
ganglia of, 1045 
-mollis of auditory nerve, 1045 
Post-anal gut, 1242 
-central gyrus, 876 
lobes, 878 
sulcus, inferior, 875 
superior, 875 
-clival, fissure, 928 
-glenoid process, 84 
-gracile fissure, 930 
-limbic fissure, 871 
-nodular fissure, 930 
-parietal convolution, 876 
-pharyngeal gland, 785 
-pyramidal fissure, 930 
Posterior auricular artery, 609 
nerve, 1047 
vein, 727 
bicipitsl ridge, 179 
calcaneo-astragaloid ligament, 
352 
carpal arch, 659 
artery of ulnar, 663 
cerebellar notch, 926 
cerebral artery, 640 
cervical plexus, 970 
chondro-sternal ligament, 288 
-xiphoid ligament, 288 
choroid artery, 640 
clinoid process, 93, 132 
commissure of brain, 903 
of cord, 839 
common ligament, 270 
condyloid foramen, 73, 133, 
136 
fossa, 136 
cornu of lateral ventricle, 889 
bulb of, 889 
coronary plexus, 1081 
costo-transverse ligament, 286 
Posterior costo-xiphoid ligament, 
288 
crescentic lobe, 928 
crucial ligament, 337 
deep cervical vein, 733 
dental canals, 106 
divisions of cervical nerves, 968 
of coccygeal nerve, 1008 
of dorsal nerves, 993 
branches, cutaneous, 
993 
external, 993 
internal, 993 
of lumbar nerves, 997 
branches, external, 998 
internal, 998 
of sacral nerves, 1006 
lower, 1007 
upper, 1006 
branches, external, 
1006 
internal, 1006 
ethmoidal canal, 82, 100 
cells, 101, 145 
foramen, 82, 130, 141 
sinuses, 101 
external jugular vein, 728 
of thoracic nerves, 993 
branches, cutaneous, 
993 
external, 993 
internal, 993 
extremity of ribs, 160 
head of, 160 
neck of, 160 
tuberosity of, 161 
femoral region, muscles of, 529 
fontanelle, 75, 103 
fossa of skull, 132 
gluteal line, 207 
humeral region, muscles of, 477 
inferior cerebellar artery, 639 
spinous process of ilium, 210 
intercostal veins, 752 
internal frontal artery, 627 
interosseous artery of ulna, 663 
nerve, 991 
interstemal ligament, 290 
intertrochanteric line, 223 
ligament of incus, 1161 
of Winslow, 335 
of wrist, 318 
longitudinal ligament, 270 
spinal veins, 755 
median fissure, 838 
ganglionic arteries, 640 
mediastinal arteries, 666 
glands, 812 
mediastinum, 1389 
medullary velum, 943 
meningeal artery, 638 
nares, 142, 1098 
nasal spine, 116, 135, 143 
occipito-atlantal ligament, 276 
-axial ligament, 278 
olfactory lobule, 881 
orbital convolution, 874 
palatine artery, 615 
canal, 107, 116 
canals, accessory, 116, 135 
foramen, 135 
nerve, 1035 
perforated lamina, 910 
space, 883 
peroneal artery, 718 
pillar of soft palate, 1212 
pillars of fornix, 896 
pubic ligament, 296 
pulmonary nerves, 1061 
plexus, 1059, 1061, 1081 
radial carpal artery, 659 
Posterior, radio-ulnar ligament,. 
315 
region, muscles of, 486 
recurrent tibial artery, 713 
root of spinal nerves, 965 
sacral foramina, 63 
sacro-coccygeal ligament, 294 
-iliac ligament, 292 
-sciatic ligament, 292 
scapular artery, 642 
nerve, 982 
region, muscles of, 472 
semicircular canal, 1165 
spinal artery, 639 
sterno-clavicular ligament, 298: 
-costal ligament, 288 
subarachnoid space, 852 
surface of liver, 1329 
of stomach, 1270 
superior dental nerves, 1032 
spinous process of ilium, 210 
temporal artery, 611, 640 
diploic vein, 734 
thoracic nerve, 983 
tibial artery, 716 
nerve, 1014 
veins, 758 
tibio-fibular region, muscles of, 
534 
-tarsal ligament, 347 
triangle of neck, 618 
tubercle of cervical vertebra, 
50 
tympano-malleolar ligament. 
1156 
ulnar recurrent artery, 662 
vein, 745 
vertebral vein, 733 
wall of tympanum, 1152 
Postero-lateral fontanelles, 103 
ganglionic arteries, C40 
tract, 843 
-median ganglionic arteries, 
628 
tract, 843 
Pouch, Douglas's, 1490 
of Prussak, 1162 
recto-vaginal, 1490 
utero-vesical, 1487, 1490 
Poupart's ligament, 436, 1515 
Pnecentral gyrus, 872 
Pre-anal fibres of levator ani, 453: 
-aortic glands, 800 
-auricular lymphatic glands„ 
781 
-central lobe, 878 
sulci, 868 
sulcus, 872 
inferior, 872 
superior, 872 
-clival fissure, 928 
-laryngeal glands, 787 
-maxillary bones, 110 
-occipital notch, 869 
-patellar bursa, 340, 518 
Precuneus of lobe of brain, 876 
Prepatellar bursa, 518 
Prepuce of clitoris, 1479 
of penis, 1455 
Pre-occipital notch, 869 
-pyramidal fissure, 930 
-sternal notch, 157 
-sternum, 157 
-tracheal fascia, 388 
glands, 787 
-vertebral fascia, 388 
Prickle cells, 1109 
Primitive fibrillae of Schultze, 822: 
sheath of Schwann, 822 
Primordial ova, 1502 
Princeps hallucis artery, 716 INDEX 
1587 
Princeps pollicis artery, 660 
Process or processes, acromion, 
174 
alveolar, 140 
angular, 80 
external, 140 
internal, 140 
of atlas, 51 
auditory, 88 
basilar, 73 
of calcaneous, greater, 243 
lesser, 243 
clinoid, anterior, 131 
middle, 93, 132 
posterior, 93, 132 
cochleariform, 91, 1153 
condyloid of lower jaw, 125 
coracoid, 175 
of jaw, 125 
of ulna, 186 
costal, 50 
ethmoidal, of inferior turbin- 
ated, 120 
falciform, 515 
hamular, of lachrymal, 113 
of sphenoid, 96 
of inferior turbinated bone, 120 
of Ingrassias, 96 
jugular, 73 
lachrymal, of inferior turbin- 
ated, 120 
of malar bone, 114 
mammillary, of lumbar verte- 
brae, 57 
mastoid, 86, 138 
mental, 122, 140 
nasal, 80 
odontoid, of axis, 52 
olecranon, 186 
olivary, 93, 131 
orbital, 118 
of malar, 114 
of palate bone, 117 
petrosal, 93 
post-glenoid, 84 
pterygoid, of palate bone, 117 
of sphenoid bone, 96 
sphenoidal, 1097 
of palate, 118 
spinous, of ilium, 210 
of sphenoid, 95 
of tibia, 233 
stylohyal, 92 
styloid, of fibula, 237 
of temporal bone, 90 
of ulna, 189 
of superior maxillary, 109, 110 
tympanohyal, 92 
unciform, 200 
of ethmoid, 100 
vaginal, of sphenoid, 95 
of temporal bone, 89 
of vertebrae, articular, 49 
zygomatic, 84 
Processus brevis of malleus, 1159 
cochleariformis, 91, 1153 
gracilis of malleus, 1158 
tubari us, 1155 
vaginalis, 1461 
Proctodseum, 1242 
Profunda artery, inferior, 656 
superior, 655 
femoris artery, 704 
vein, 759 
Projection fibres of cerebrum, 
914, 932 
centrifugal, 914 
centripetal, 914 
motor, 914 
sensory, 914 
Prominentia styloideae, 1153 
Promontory of sacrum, 61 
of tympanum, 1152 
Pronator quadratus muscle, 483 
radii teres muscle, 479 
surgical anatomy of, 
479 
ridge, 188 
Pro-otic portion of temporal 
bone, 91 
Prosencephalon, 864 
Prostate gland, 1447 
apex of, 1451 
arteries of, 1452 
base of, 1451 
capsule of, 1449 
isthmus of, 1451 
lobes of, 1451 
lymphatics of, 1452 
vessels of, 803 
nerves of, 1452 
sheath of, 1449 
structure of, 1452 
surfaces of, 1451 
surgical anatomy of, 1452 
veins of, 1452 
Prostatic ducts, orifices of, 1442 
plexus of nerves, 1086 
of veins, 761 
portion of rectum, 1313 
of urethra, 1441 
secretion, 1452 
sinus, 1442 
vesicle, 1442 
Prostatico-vesical plexus, 761 
surgical anatomy of, 762 
Proto vertebrae, 1235 
Protuberance, mental, 122 
occipital, external, 71, 136 
internal, 73 
Prussak, pouch of, 1162 
Psalterium, 896 
Pseudostomata, 1246 
Psoas magnus muscle, 509 
parvus muscle, 500 
Pterion, 137 
ossicle, 83, 103 
Pterygoid artery, 614 
canal, 135 
depression, 125 
fissure, 96 
fossa of jaw, 115 
of sphenoid, 96 
muscles, external, 383 
internal, 383 
nerve, external, 1037 
internal, 1037 
notch, 96 
plate, external, 96 
internal, 96 
plexus of veins, 727 
process of palate bone, 117 
of sphenoid bone, 96 
ridge, 95, 137 
tubercle, 97 
Pterygo-mandibular ligament, 
380 
region, dissection of, 383 
muscles of, 383 
actions of, 384 
nerves of, 384 
-maxillary fissure, 139 
ligament, 380 
-palatine artery, 616 
canals, 135 
fossa, 139 
groove, 116 
nerve, 1036 
Pubic arch, 217 
ligament, anterior, 296 
inferior, 296 
posterior, 296 
Pubic ligament, superior, 296 
portion of fascia lata, 1528 
surface of bladder, 1434 
Pubis, 212 
angle of, 212 
body of, 212 
ramus of, ascending, 213 
descending, 213 
spine of, 
Pubo-capsular ligament, 328 
-coccygeus muscle, 452 
-femoral ligament, 328 
-prostatic ligament, 1435, 
1451 
-vesical ligament, 1435 
muscle, 1437 
Pudendal nerve, inferior, 1011 
plexus of nerves, 1009 
slit, 1478 
Pudendum, 1477 
Pudic artery, accessory, 690 
external, deep, 704 
superficial, 704 
internal, in female, 692 
in male, 689 
branches of, 690 
peculiarities of, 690 
surgical anatomy of, 
690 
nerve, 1011 
plexus of, 1009 
vein, internal, 760 
Pulmonary alveoli, 1378 
artery, 587 
left, 587 
opening of, 569 
right of, 587 
branches of thoracic portion 
of gangliated cord, 1079 
lymphatics, 815 
nerves, anterior, 1061 
posterior, 1061 
pleura, 1385 
plexus, 1081 
anterior, 1059, 1061, 1082 
posterior, 1059, 1061, 1081 
sinuses of Valsalva, 571 
veins, 723 
Pulmonic semilunar valves, 571 
Pulp, dental, 1200 
Pulvinar of optic thalamus, 904 
Puncta lacrimalia, 1142 
vasculosa, 885 
Punctum lacrimale, 1138 
Pupil of eye, 417 
Pupillary margin, 1117 
Purkinje, axis-cylinder of, 822 
cells of, 825 
corpuscles of, 936 
Putamen, 892 
Pyloric artery, inferior, 673 
superior, 673 
glands, 1277 
orifice of stomach, 1270 
plexus, 1085 
portion of stomach, 1269 
sphincter, 1272 
valve, 1272 
Pylorus, 1270 
antrum of, 1271 
Pyramids of Ferrein, 1417 
of Lalouette, 1403 
lobe of cerebellum, 931 
of Malpighi, 1417 
of medulla, 939 
of tympanum, 1153 
of vestibule of ear, 1164 
Pyramidal decussation, 947 
tract, crossed, 842 
direct, 842 
uncrossed, 842 1588 
INDEX 
Pyramidalis, muscle, 444 
nasi muscle, 375 
Pyriformis muscle, 524 
bursa of, 525 
Q 
Quadrate lobe of liver, 1332 
lobule, 875 
Quadratus femoris muscle, 527 
lumborum, fascia of, 449 
muscle, 449 
menti muscle, 378 
relations of, 378 
Quadriceps extensor muscle, 516 
Quadrigeminal bodies, 911 
Quadrilateral, muscles, 362 
R 
Radial artery, 657 
branches of, 659 
peculiarities of, 658 
relations of, 657 
surface marking of, 658 
surgical anatomy of, 658 
fossa, 181 
head of humerus, 181 
nerve, 991 
recurrent artery, 659 
region, muscles of, 484, 495 
dissection of, 484 
vein, 745 
Radialis indicis artery, 660 
Radiations, optic, 905 
Radio-carpal articulations, 317 
surface form of, 318 
surgical anatomy of, 318 
-ulnar articulation, 313 
inferior, 315 
surface form of, 317 
middle, 314 
superior, 314 
surface form of, 314 
surgical anatomv of, 
314 
ligaments, annular, 314 
anterior, 315 
oblique, 314 
orbicular, 314 
posterior, 315 
round, 314 
region, anterior, muscles of, 
479 
surgical anatomy of. 
484 
posterior, muscles of, 486 
surgical anatomv of, 
491 
Radius, 190 
articulations of, 192 
attachment of muscles to, 
192 
development of, 192 
lower extremity of, 191 
shaft of, 190 
borders of, 190, 191 
surfaces of, 191 
sigmoid cavity of, 191 
structure of, 192 
surface form of, 192 
surgical anatomy of, 192 
upper extremity of, 190 
Rami of lower jaw, 124 
Ramus of ischium, ascending, 
212 
descending, 211 
of pubis, ascending, 213 
descending, 213 
Ranine artery, 604 
vein, 729 
Raphe of corpus callosum, 887 
of medulla, 951 
of palate, 1211 
of perineum, 1537 
of scrotum, 1463 
of tongue, 1087 
Receptaculum chyli, 775 
Recess, epitympanic, 87 
Recessus cochlearis of Reichert, 
1164 
Reciprocal reception, articula- 
tion by, 265 
Rectal columns, 1319 
glands, 809 
valves, 1318 
Recto-urethralis muscle, 454 
-uterinus muscle, 1491 
-vaginal fold, 1490 
pouch, 1314, 1490 
-vesical fascia, 1546 
pouch, 1314 
Rectum, 1312 
areolar coat of, 1318 
arteries of, 1320 
curves of, 1313 
lymphatics of, 809, 1321 
mucous membrane of, 1318 
muscular coat of, 1317 
nerves of, 1322 
prostatic portion of, 1313 
sacrococcygeal portion of, 
1313 
serous coat of, 1316 
submucous coat of, 1318 
surface form of, 1323 
surgical anatomy of, 1325 
supports of, 1315 
structure of, 1316 
veins of, 1321 
Rectus abdominis muscle, 442 
capitis anticus major muscle, 
406 
minor muscle, 407 
lateralis muscle, 407 
posticus major muscle, 422 
minor muscle, 422 
femoris muscle, 516 
oculi muscle, external, 373 
inferior, 373 
internal, 373 
superior, 373 
Recurrent artery, palmar, 660 
radial, 659 
tibial, anterior, 713 
posterior, 713 
ulnar, anterior, 662 
posterior, 662 
laryngeal nerve, 1060 
Red nucleus nerve-path, 960 
Reflections of pleurae, 1384 
Reflex nerve-paths, 963 
Refracting media of eye, 1128 
Reichert, recessus cochlearis of, 
1164 
Reil, island of, 867, 878 
sulcus of, limiting, 867, 878 
Reissner, membrane of, 1172 
Remak, fibres of, 823 
Renal artery, 678 
inferior, 1423 
blood-vessels, 1422 
impression of liver, 1329 
plexus, 1061, 1084 
surface of spleen, 1354 
veins, 767 
zone of Hyrtl, exsanguinated, 
1423 
Reservoir of Pecquet, 775 
Respiration, muscles of, 431 
Respiration, organs of, 1361 
Respiratory nerve of Bell, ex- 
ternal, 983 
internal, 974 
Restiform body of medulla, 941 
Rete testis of Haller, 1471 
Retina, 1120 
nerve-fibres of, 1122 
physiological, 1120 
pigmentary layer of, 1127 
rods of, 1125 
structure of, 1121 
supporting framework of, 1127 
Retinacula of capsular ligament 
of hip, 327 
patella? mediale, 517 
Retrahens auriculam muscle, 369 
Retro-aortic glands, 800 
-caecal fossa, 1263 
-colic fossa?, 1263 
-crural glands, 798 
-duodenal fossa, 1262 
-peritoneal fossa?, 1260 
space, 1247 
-pharyngeal glands, 785 
space, 388, 1220 
-rectal space, 1314 
-renal fascia, 1412 
-sternal glands, 810 
Retzius, brown stria' of, 1204 
fundiform ligament of, 541 
space of, 1434 
Rhinencephalon, 880 
Rhodopsin, or visual purple, 1120 
Rhombencephalon, 922 
Rhomboid fossa, inferior, 840 
impression, 169 
ligament, 298 
Rhomboidal muscles, 363 
Rhomboideus major muscle, 414 
minor muscle, 414 
Ribes, ganglion of, 1067 
Ribs, 159 
anterior extremity of, 161 
articulations of, 283 
attachment of muscles to, 164 
cervical, 53 
common characters of, 160 
development of, 163 
false, 159 
floating, 160 
peculiar, 162 
posterior extremity of, 160 
shaft of, 161 
structure of, 163 
true, 159 
Ridges, bicipital, 179 
epicondylic, 179 
gluteal, 224 
mylo-hyoid, 123 
naso-labial, 377 
oblique, of trapezium, 198 
of ulna, 188 
pectoral, 179 
pronator, 188 
pterygoid, 95, 137 
superciliary, 80 
supracondylar, external, 179 
internal, 180 
supraorbital, 140 
temporal, 76, 80 
trapezoid, 169 
Riedel's lobe of liver, 1336 
Right ascending lumbar vein, 
752 
azygos vein, 752 
bronchus, 1376 
cardiac vein, 771 
colic artery, 675 
coronary artery, 590 
plexus, 1081 INDEX 
1589 
Right innominate vein, 750 
juxta-aortic glands, 800 
lobe of liver, 1332 
lymphatic duct, 778 
superior intercostal vein, 752 
Rinja glottidis, 1369 
Ring, abdominal, internal, 446 
crural, 437, 1532 
femoral, 437, 509, 1532 
fibrous, of heart, 574 
muscle of Muller, 1116 
Risorius muscle, 380 
Risus sardonicus, 381 
Rivinus, ducts of, 1217 
notch of, 1151 
Rod-bipolars, 1125 
-cells, 1126 
-fibre, 1126 
-granules, 1125 
Rolandic angle, 867 
Rods of Corti, 1174 
of retina, 1125 
Rolando, fasciculus of, 941 
fissure of, 867 
funiculus of, 941 
sulcus of, central, 867 
tubercle of, 941 
Roots of auditory nerve, 1050 
of cervical nerves, 968 
of dorsal nerves, 993 
of eighth nerve, 1050 
of fifth nerve, ascending, 948, 
1026 
descending, 1026 
of lumbar nerve, 997 
of lung, 1394 
of penis, 1454 
of pneumogastric nerve, gan- 
glion of, 1059 
of sacral nerves, 1006 
of spinal nerves, 965 
anterior, 965 
dorsal, 965 
posterior, 965 
ventral, 965 
of thoracic nerves, 993 
of tongue, 1087 
Rosenmuller, fossa of, 1221 
gland of, 795 
accessory, 1141 
organ of, 1499 
Rostrum of corpus callosum, 
886 
of sphenoid bone, 94, 135 
Rotary joint, 265 
Rotatores spinae muscle, 421 
Round ligament, artery of, 688 
of liver, 1334 
of uterus, 1491 
Roux's amputation of foot, 256 
Rudimentary organ of Jacobson, 
1100 
Rudinger, dilator tuba; muscle 
of, 1155 
Ruffini's nerve-endings, 828 
Rugae of scrotum, 1462 
of stomach, 1275 
of vagina, 1484 
Ruysch, tunic of, 1113 
S 
Sacs, abdominal, 1236 
dental, 1206 
lachrymal, 1142 
pericardial, 1236 
pleural, 1236 
Saccule of vestibule, 1170 
Sacculi alveSlares, 1378 
Sacculus laryngis, 1371 
Sacral artery, lateral, 693 
middle, 681 
canal, 64 
cornua, 62 
foramina, anterior, 62 
posterior, 63 
groove, 63 
lymphatic glands, 799 
nerve, 1006 
division of, anterior, 1007 
posterior, 1006 
roots of, 1006 
plexus, 1009, 1086 
portion of gangliated cord, 
1080 
veins, lateral, 760 
middle, 764 
Sacro-coccygeal ligament, ante- 
rior, 294 
lateral, 295 
posterior, 294 
portion of rectum, 1313 
symphisis, 66 
-iliac ligament, anterior, 292 
interosseous, 292 
long, 292 
oblique, 292 
posterior, 292 
short 292 
-lumbalis muscle, 419 
-sciatic foramen, great, 211, 
294 
inferior, 294 
lesser, 211, 294 
superior, 294 
ligament, anterior, 293 
great, 292 
lesser, 293 
posterior, 292 
notches, 217 
great, 210 
lesser, 211 
-uterine ligaments, 1490 
-vertebral angle, 61 
Sacrum, 61 
ala of, 64 
apex of, 64 
articulations of, 65 
attachment of muscles to, 65 
base of, 64 
development of, 64 
differences in the male and 
female, 64 
peculiarities of, 64 
promontory of, 61 
structure of, 64 
surfaces of, 61 
tuberosity of, 63 
Saddle-joint, 265 
Sagittal axis, 1106 
sulcus, 73, 80 
suture, 78, 127 
Salivary glands, 1214 
structure of, 1217 
surgical anatomy of, 1224 
Salpingo-palatine fold, 1221 
-pharyngeal fold, 1221 
-pharyngeus muscle, 405 
Salter, incremental lines of, 
1203 
Santorini, cartilages of, 1365 
comical tubercle of, 1368 
fissures of, 1146, 1148 
muscle of, 380 
Saphenous gland, external, 795 
opening, 514, 1529 
nerve, internal, 1005 
long, 1005 
vein, external, 756 
internal, 756 
long, 756 
Saphenous vein, short, 756 
surgical anatomy of, 757 
Sarcolemma, 361 
Sardonic laugh, 381 
Sartorius muscle, 516 
nerve to, 1005 
Scala media, 1172 
tympani of cochlea, 1168 
vestibuli of cochlea, 1168 
Scalenus muscles, anticus, 408 
medius, 408 
posticus, 409 
Scalp, skin of, 366 
Scapha, fossa of, 1145 
Scaphoid bone of foot, 246 
articulations of, 247 
attachment of muscles to, 
247 
surfaces of, 246 
tuberosity of, 246 
of hand, 195 
articulations of, 196 
attachment of muscles to, 
196 
surfaces of, 196 
fossa, 97, 135, 1145 
Scapula, 171 
angles of, 174 
articulations of, 176 
attachment of muscles to, 176 
base of, 174 
borders of, 174 
development of, 175 
dorsum of, 172 
head of, 174 
ligaments of, 301 
spine of, 172 
structure of, 175 
surface form of, 176 
surgical anatomy of, 177 
venter of, 171 
Scapular arteries, posterior, 642 
glands, 790 
nerve, posterior, 982 
notch, great, 173 
region, anterior, muscles of, 
471 
dissection of, 471 
posterior, muscles of, 472 
dissection of, 472 
Scapulo-clavicular articulation, 
299 
Scarf skin, 1181 
Scarpa, fascia of, 433 
foramina of, 110, 135, 1036 
membrane of, 1152 
nerve of, 1036 
triangle of, 516, 697 
Schachowa, spiral tube of, 1419 
Schindylesis, 264 
Schlemm, canal of, 1108, 1111 
ligament, 305 
Schneiderian membrane, 1100 
Schreger, concentric lines of, 1203 
Schultze, primitive fibrillae of, 822 
Schwann, nucleated sheath of, 
822 
primitive sheath of, 822 
white substance of, 822 
Sciatic artery, 692 
nerve, great, 1013 
branches of, 1013 
small, 1011 
branches of, 1011 
notch, great, 210 
plexus, 1009 
veins, 761 
Sclera, 1107 
structure of, 1108 
Scleral sulcus, 1105 
Sclerotic coat, 1107 1590 
INDEX 
Scrotal hernia, 1521 
nerve, long, 1011 
Scrotum, 1462 
arteries of, 1465 
dartos of, 1463 
integument of, 1463 
lymphatic vessels of, 801 
lymphatics of, 1466 
nerves of, 1466 
raphe of, 1463 
rug® of, 1462 
septum of, 1463 
surgical anatomy of, 1469 
veins of, 1466 
Sebaceous glands, 1138, 1191 
Second nerve, 1021 
Secondary ear-drum membrane, 
1152 
Segments of Lantermann, 823 
Sella turcica, 93, 131 
Semen, 1474 
Semicircular canals, 1165 
external, 1165 
horizontal, 1165 
membranous, 1170 
posterior, 1165 
superior, 1165 
muscles of rectum, 1317 
Semilunar bone, 196 
articulations of, 197 
surfaces of, 196 
fascia, 476 
fibro-cartilages, 337 
external, 339 
internal, 338 
folds of colon, 1317 
of Douglas, 439, 444 
ganglion of abdomen, 1084 
of fifth nerve, 1027 
hiatus, 145, 747 
lobe of cerebellum, inferior, 
931 
valves, aortic, 572 
pulmonic, 571 
Semimembranosus muscle, 530 
bursa of, 531 
Seminal duct, 1472 
vesicles, 1475 
arteries of, 1476 
lymphatic vessels of, 804 
lymphatics of, 1476 
nerves of, 1476 
structure of, 1476 
surgical anatomy of, 1476 
veins of, 1476 
Semispinalis colli muscle, 421 
dorsi muscle, 421 
Semitendinosus muscle, 530 
Sensory decussation, 947 
nerve tract, 961 
projection fibres of cerebrum, 
914 
Septo-marginal tract, 844 
Septum atriorum, 567 
bronchial, 1380 
crurale, 1532 
of Cloquet, 509 
interarticular, 565 
interventricular, 569 
lucidum, 889, 896 
of nose, 142 
cartilage of, triangular, 1097 
orbital, 1139 
pectiniforme, 1457 
of scrotum, 1463 
of tongue, fibrous, 398 
transversum, 1170 
Serous coat of anal canal, 1316 
of bladder, 1437 
of gall-bladder, 1343 
of large intestine, 1316 
Serous coat of lungs, 1354 
of rectum, 1316 
of small intestine, 1290 
of spleen, 1356 
of stomach, 1273 
of vermiform appendix, 
1304 
covering of ovary, 1501 
pericardium, 560 
Serratus magnus muscle, 468 
posticus inferior muscle, 415 
superior muscle, 415 
Sertoli, cell of, 1472 
Sesamoid bones, 257 
cartilage, 1097 
Seventh nerve, 1044 
surgical anatomy of, 1049 
Shaft of bone, its structure, 33 
of hair, 1189 
of ribs, 161 
Sharpey, fibres of, 37 
Shrapnell, membrana flaccida of, 
1156 
Sheath, carotid, 388 
dentinal, of Neumann, 1203 
femoral, 509, 1530 
of flexor tendons, fibrous, 545 
granular, of Tomes, 1202 
nucleated, of Schwann, 822 
primitive, of Schwann, 822 
of prostate, 1449 
of rectus muscles, 443 
Shin bone, 233 
Short bones, 33 
calcaneo-cuboid ligament, 353 
ciliary arteries, 625 
fibre nerve path, 960, 963 
plantar ligament, 353 
sacro-iliac ligament, 292 
saphenous vein, 756 
Shoulder, fascia of, deep, 470 
superficial, 470 
girdle, 167 
-joint, articulations of, 303 
bursa; of, 305 
surface form of, 307 
surgical anatomy of, 307 
muscles of, 470 
Sibson, aortic vestibule of, 572 
aponeurosis, 1385 
Sigmoid arteries, 678 
cavity of radius, 191 
of ulna, 186 
colon, 1311 
flexure of colon, 1311 
of large intestine. 1300 
fossa, 86 
mesocolon, 1259 
notch of lower jaw, 125 
plexus, 1085 
sinus, 739 
sulcus, 86 
Sinus or sinuses, air, 82 
al® parv®, 740 
of aorta, great, 589 
basilar, 743 
cavernous, 739 
circular, 742 
confluence of, 737 
coronary vein, 567, 771 
costo-mediastinal, 1386 
of dura mater, 736 
ethmoidal, 101 
frontal, 80 
of heart, auricle of, left, 568 
right, 565 
intercavernous, 742 
of jugular vein, external, 728 
internal, 729 
of kidney, 1415 
laryngeal, 1371 
Sinus or sinuses, lateral, 738 
longitudinal, inferior, 738 
superior, 78, 130, 736 
maxillary, 108 
of Morgagni, 402 
of nose, 80 • 
occipital, 739 
orbital, 118 
petro-squamous, 739 
petrosal, inferior, 742 
superior, 742 
of pericardium, oblique, 560 
transverse, 560 
phrenico-costal, 1386, 1414 
pocularis, 1442 
portal, 769 
prostatic, 1442 
pyriformis, 1222, 1368 
sigmoid, 739 
spheno-parietal, 740 
sphenoidal, 94, 143 
straight, 738 
tonsillaris, 1222 
transverse, 743 
pericardial, 560 
utricularis sacculi, 1170 
of Valsalva, aortic, 573 
pulmonary, 571 
venosus, 565 
Sixth nerve, 1043 
branches of, 1043 
nucleus of, 925 
relations of, 1043 
surgical anatomy of, 
1044 
Skeletal muscles, 361 
Skin, 1178 
appendages of, 1185 
arteries of, 1184 
bone, 233 
cuticle of, 1181 
epidermis, 1181 
folds of, 1178 
furrows, 1179 
horny layer of, 1181 
lymphatics of, 1184 
Malpighian layer of, 1182 
nerves of, 1184 
papillary layer of, 1181 
pigmentation of, 1182 
, ridges, 1179 
of scalp, 366 
scarf, 1181 
stratum cylindricum, 1182 
germinativum, 1182 
granulosum, 1182 
lucidum, 1182 
mucosum, 1182 
spinosum, 1182 
true, 1180 
veins of, 1184 
Skull, anterior region of, 139 
base of, 130 
at different ages, 102 
fixed point for measurement of, 
149 
fossa of, anterior, 130 
infratemporal, 138 
middle, 130 
orbital, 140 
posterior, 132 
pterygo-palatine, 139 
spheno-maxillary, 139 
temporal, 137 
zygomatic, 138 
lateral regions of, 136 
sexual differences in, 102 
surface form of, 147 
surgical anatomy of, 149 
tables of, 33 
vitreous, 34 INDEX 
1591 
Spheno-parietal sinus, 740 
suture, 128 
-phrenic ligament, 1256 
Sphenoid bone, 92 
articulations of, 98 
attachment of muscles to, 
98 
body of, 92 
surfaces of, 93 
development of, 97 
greater wings of, 95 
circumference of, 95 
surfaces of, 95 
hamular process of, 96 
lesser wings of, 96 
pterygoid process of, 96 
rostrum of, 94, 135 
Sphenoidal cells, 94 
crest, 94 
fissure, 96, 132 
process, 1097 
of palate bone, 118 
sinuses, 94, 143 
spine, 95 
spongy bones, 97 
turbinated bones, 143 
Spherical recess, 1164 
Sphincter ani muscle, external, 
450 
internal, 451 
muscles, 363 
py loris, 1272 
vaginae muscle, 461 
Spigelian lobe of liver, 1330 
Spina tympanica major, 1151 
minor, 1151 
Spinal accessory nerve, 1063 
accessory portion, 1063 
bulbar portion, 1063 
nucleus of, 950 
spinal portion, 1063 
surgical anatomy of, 1063 
arteries, anterior, 638 
lateral, 638 
posterior, 639 
bulb, 938 
canal, 69 
column, 48 
cord, 836 
arachnoid membrane of, 
834 
blood supply of, 840 
central canal of, 840 
columns of, 838 
commissure of, 839 
cornu of, caput, 839 
cervix, 839 
dissection of, 832 
dura mater of, 832 
fibres of, 841 
fissures of, 837 
gray substance of, 845 
grooves of, 837 
lymphatics of, 840 
membranes of, 832 
minute anatomy of, 840 
neuroglia of, 840 
olivary bundle of, 843 
pia mater of, 835 
structure of, 839 
tracts of, conducting, 841 
functions of, 844 
veins of, 755 
white substance of, 841 
cranial reflexes, 963 
foramen, 49 
nerves, 964 
accessory, 1063 
distribution of, 967 
ganglia of, 966 
origin of, 847 
Spinal nerves, points of emer- 
gence of, 967 
roots of, 965 
reflexes, 963 
veins, 753 
longitudinal, anterior, 754 
posterior, 755 
plexus of, 753 
Spinalis colli muscle, 420 
dorsi muscle, 419 
Spindle, aortic, 591 
Spindles, neuro-muscular, 829 
neuro-tendinous, 829 
Spine, articulations of, 276 
ethmoidal, 93, 130 
frontal, 80 
of helix, 1146 
of Henle, 88 
of ischium, 211 
mental, 123 
nasal, 80 
anterior, 111, 139, 143 
posterior, 116, 135, 143 
palatine, 116 
peroneal, 243 
pharyngeal, 73, 135 
progress of ossification in, 60 
of pubis, 212 
of scapula, 172 
sphenoidal, 95 
suprameatal, 88 
Spino-glenoid ligament, 302 
Spinous processes of ilium, 210 
of tibia, 233 
of vertebra?, 49 
Spiral canal of cochlea, 1167 
ligament of cochlea, 1172 
line of femur, 223 
tube of Schachowa, 1419 
Splanchnic nerves, 1079 
Splanchnopleure, 1236 
Spleen, 1353 
accessory, 1355 
arteries of, 1357 
development of, 1245 
fibro-elastic coat of, 1356 
hilum of, 1354 
lymphatics of, 807, 1359 
Malpighian bodies of, 807, 1358 
movability of, 1356 
movable, 1356 
nerves of, 1359 
serous coat of, 1356 
structure of, 1356 
support of, 1356 
surface form of, 1359 
surgical anatomy of, 1359 
veins of, 1359 
Splenic artery, 674 
flexure of colon, 1309 
of large intestine, 1300 
glands, 800 
plexus, 1061, 1085 
pulp, 1356 
vein, 768 
Splenium of corpus callosum, 
886 
Splenius muscle, 416 
Spongy portion of urethra, 1443 
tissue of bone, 33 
Spur, femoral, 227 
Squamo-parietal suture, 128 
-sphenoidal suture, 128 
Squamous portion of occipital 
bone, 71 
suture, 85, 128 
Square lobe of liver, 1332 
Stahr, middle gland of, 784 
Stapedius muscle, 1160 
Stapes, 1160 
base of, 1160 
Skull, vertex of, 129 
Slender funiculus, 941 
lobe of cerebellum, 931 
Small coronary vein, 771 
intestine, 1282 
lymphatic glands of, 807 
vessels of, 808 
occipital nerve, 972 
palatine nerve, 1035 
sciatic nerve, 1011 
Socia parotidis, 1215 
Soft commissure of brain, 903 
palate, 1211 
aponeurosis of, 1212 
arches of, 1211 
arteries of, 1212 
mucous membrane of, 1212 
muscles of, 1212 
nerves of, 1213 
pillars of, 1211 
veins of, 1213 
Solar plexus, 1083 
Soleus muscle, 535 
Solitary glands, 1295, 1320 
Somatopleure, 1236 
Sommerring, foramen of, 1121 
yellow spot of, 1121 
Space or spaces, axillary, 645 
of Bruns, 388 
cartilage, 260 
corneal, 1110 
epitympanic, 87 
of Fontana, 1110 
intercostal, 160 
interglobular, of Czermak, 
1202 
interpeduncular, 882 
interpleural, 1387 
mediastinal, 1387 
of Nuel, 1175 
perichoroidal, 1108 
perisclerotic, 1103 
pneumatic, 1103 
popliteal, 707 
retro-peritoneal, 1247 
-pharyngeal, 388, 1220 
of Retzius, 1434 
suprascleral, 1104 
suprasternal, 388 
Special sense, organs of, 1087 
Spermatic arteries, 679 
canal, 448, 1517 
cord, 1466 
arteries of, 1467 
lymphatics of, 1468 
nerves of, 1468 
structure of, 1466 
surgical anatomy of, 1468 
veins of, 1467 
fascia, 1463 
external, 1436, 1514 
internal, 446 
middle, 440 
plexus of nerves, 1084 
of veins, 765 
vein, 765 
surgical anatomy of, 766 
Spermatids, 1472 
Spermatoblasts, 1472 
Spermatocytes, 1472 
Spermatogenesis, 1472 
Spermatogonia, 1472 
Spermatozoid, 1472, 1474 
Spheno-ethmoidal recess, 145 
-maxillary fissure, 115, 138 
fossa, 115, 139 
-palatine artery, 616 
foramen, 119, 143 
ganglion, 1034 
nerves, 1032 
notch, 118 1592 
INDEX 
Stapes, crura of, 1160 
foot-plate, 1160 
head of, 1160 
ligament of, 1161 
neck of, 1160 
Statoliths, 1171 
Stellate ligament, 284 
reticulum, 1206 
Stenson, duct of, 1215 
foramina of, 110 
Stephanion, 137 
inferior, 76 
superior, 76 
Sternal arteries, 644 
foramen, 157 
furrow, 165 
glands, 810 
ribs, 159 
Sterno-clavicular articulations, 
297 
surface form of, 299 
surgical anatomy of, 297 
-cleido-mastoid muscle, 389 
-costal ligament, anterior, 
288 
interarticular, 288 
posterior, 288 
-costo pericardial ligament, 
559 
-hyoid muscle, 391 
-mastoid artery, 602, 609 
glands, 786 
muscle, 389 
surface form of, 391 
surgical anatomy of, 391 
-pericardiac ligaments, 558. 
-thyroid muscle, 392 
Sternum, 155 
angle of, 157 
articulations of, 159, 290 
attachment of muscles to, 159 
development of, 158 
ensiform appendix of, 158 
gladiolus, 157 
ligaments of, 290 
manubrium of, 157 
structure of, 158 
surface form of, 165 
surgical anatomy of, 165 
xiphoid appendix of, 158 
Stigmata, 1246 
Stilling, canal of, 1129 
nucleus of, red, 938 
Stomach, 1268 , 
alterations in position of, 1271 
areolar coat of, 1274 
arteries of, 1278 
body of, 1269 
cardiac orifice of, 1270 
portion of, 1269 
chamber, 1269 
curvatures of, 1270 
fundus of, 1269 
innervation of, 1280 
lymphatic vessels of, 806, 1279 
movements of, 1280 
mucous membrane of, 1275 
muscular coat of, 1273 
nerves of, 1279 
oesophageal opening of, 1270 
peritoneal coat of, 1273 
pit of, 165 
pyloric orifice of, 1270 
portion of, 1269 
relations of, 1269 
rugae of, 1275 
serous coat of, 1273 
structure of, 1273 
submucous coat of, 1274 
supports of, 1272 
surface form of, 1280 
Stomach, surfaces of, 1269 
surgical anatomy of, 1280 
-teeth, 1197 
vascular coat of, 1274 
veins of, 1279 
Stomata, 1246 
Straight sinus, 738 
Stria vascularis, 1172 
Striated muscle, 361 
Striped muscle, 361 
Stroma of iris, 1118 
of ovary, 1501 
plexus of, 1111 
Stylo-glossus muscle, 397 
-hyal process, 92 
-hyoid ligament, 394 
muscle, 394 
nerve, from facial, 1048 
-mandibular ligament, 281, 388 
-mastoid artery, 610 
foramen, 90, 135 
-maxillary ligament, 281 
-pharyngeus muscle, 403 
Styloid process of fibula, 237 
of temporal bone, 90 
of ulna, 189 
Subacromial bursa, 305, 471 
Subanconeus muscle, 478 
Subarachnoid cisterna*, 852 
space, 834, 852 
Subarachnoidean areolar tissue, 
851 
space, 834 
Subcalcarine convolution, 877 
Subcallosal gyrus, 882 
Subclavian artery, 631 
branches of, 637 
first part of, left, 633 
right, 632 
peculiarities of, 635 
second part of, 633 
surface form of, 635 
surgical anatomy of, 635 
third part of, 633 
glands, 791 
groove, 169 
loop, 1076 
muscle, 468 
plexus of nerves, 1077 
triangle, 618 
vein, 749 
Subclavius muscle, 468 
Subcollateral convolution, 878 
Subcostal artery, 667 
groove, 162 
Subcrureus muscle, 518 
Subcutaneous acromial bursa, 
305 
areolar tissue, 1180 
olecranon bursa, 477 
synovial bursa, 263 
tibial bursa, 340 
trochanteric bursa, 331 
Subdeltoid bursa, 305, 471 
Subdural space, 834, 847 
Subepithelial plexus, 1111 
Sublingual artery, 604 
fossa, 123 
gland, 1217 
Sublobular veins, 767 . 
Submaxillary artery, 606 
fossa, 123 
ganglion, 1040 
arteries of, 1217 
branches of, 1040 
ducts of, 1216 
glands, 784, 1216 
lymphatics of, 1217 
nerves of, 1217 
veins of, 1217 
triangle, 394, 617 
Submaxillary vein, 727 
Submental artery, 606 
glands, 785 
vein, 727 
Suboccipital lymphatic glands, 
780 
nerves, 968 
triangle, 423 
Suborbital glands, 782 
Subparotid glands, 1215 
lymphatic glands, 782 
Subpleural mediastinal plexus, 
644 
Subpubic ligament, 296 
Subscapular angle, 172 
artery, 651 
bursa, 305 
fascia, 471 
fossa, 171 
nerves, 984 
Subscapularis muscle, 471 
Subserous areolar coat of lungs, 
1394 
tissue, 1245 
connective tissue, 1246 
Substantia cinerea glutinosa, 841 
ferruginea, 945 
glutinosa centralis, 840 
nigra, 910 
propira of cornea, 1110 
Substerno-mastoid glands, 786 
Subtendinous iliac bursa, 331 
synovial bursa, 263 
Subthalamic region, 905, 913 
tegmental region, 885 
Suburethral gland, 1482 
Sucking pad, 380 
Suctorial pad, 380 
Sudoriferous glands, 1190 
Sulci, occipital, 876 
Sulcus, callosal, 879, 885 
calloso-marginal, 868, 870 
diagonalis, 868 
dorso-median, 838 
frontal, 873 
frontalis, inferior, 868 
medius, 868, 873 
superior, 868 
interparietalis, 868 
intraparietal, of Turner, 875 
lachrymal, 113 
lateralis mesencephali, 885 
, nervi oculo-motorii, 885 
occipitalis transversus, 868 
occipito-temporal, 870 
oculomotorius, 906 
olfactory, 870, 874 
orbital, 870, 874 
orbito-palpebral, inferior, 1137 
superior, 1137 
paramedialis, 868, 873 
parieto-occipital, 867 
internal, 870 
post-central, 875 
inferior, 868 
superior, 868 
posterior median, 838 
precentral, 872 
inferior, 868 
superior, 868 
of Reil, limiting, 867, 878 
of Rolando, central, 867 
sagittal, 73, 80 
scleral, 1105 
sigmoid, 86 
spiralis externus, 1172 
intern us, 1172 
temporal, 877 
inferior, 868, 870 
superior, 868 
terminalis of His, 566, 1087 INDEX 
1593 
Sulcus, tri-radiate, 874 
tympanic, 1149 
tympanicus, 1151 
Superciliary ridge, 80 
Superficial anterior thoracic 
nerve, 984 
branches of cervical plexus, 
972 
cardiac plexus, 1081 
cerebellar veins, 736 
cerebral veins, 735 
cervical artery, 642 
fascia, 386 
glands, 784 
nerve, 973 
region, muscles of, 386 
circumflex iliac artery, 704 
vein, 756 
crural arch, 436, 1529 
dorsal veins of penis, 762 
epigastric artery, 704 
external pudic artery, 704 
fascia, 364 
of abdomen, 433, 1511 
of arm, 470 
of back, 411 
of cranial region, 366 
of femoral region, 512 
•f perinaeum in male, 455 
of shoulder, 470 
of thoracic region, 463 
femoral artery, 700 
inguinal lymphatic glands, 793 
long plantar ligament, 353 
lymphatic glands of upper ex- 
tremity, 788 
vessels of gluteal region, 801 
of lower extremity, 797 
of penis, 801 
of perinaeum, 801 
of scrotum, 801 
of upper extremity, 792 
of walls of abdomen, 801 
muscles of abdomen, 432 
palmar arch, 664 
parotid lymphatic glands, 781 
perineal artery, 690 
sural artery, 710 
Sylvian vein, 735 
temporal artery, 611 
nerves, 1038 
vein, 727 
transverse ligament of fingers, 
494 
veins of fingers, 745 
of foot, 756 
of hand, 745 
of lower extremity, 756 
of upper extremity, 745 
Superficialis colli nerve, 973 
volae artery, 659 
Superior acromio-clavicular lig- 
ament, 299 
astragalo-scaphoid ligament, 
354 
branch of superior cervical 
ganglion, 1073 
calcaneo-cuboid ligament, 353 
-scaphoid ligament, 353 
cardiac nerve, 1076 
carotid triangle, 394 
cerebellar artery, 640 
peduncles, 932 
cerebral veins, 735 
cervical ganglion, 1072 
constrictor muscle, 401 
coronary artery of lip, 607 
dental plexus, 1033 
epigastric artery, 645 
glands, 802 
fibular artery, 713 
Superior flexure of duodenum, 
1285 
frontal convolution, 873 
gemellus muscle, 526 
gluteal nerve, 1010 
hsemorrhoidal artery, 678 
plexus of nerves, 1085 
veins, 768 
intercostal artery, 645 
veins, 752 
lachrymal gland, 1141 
nerve, 1060 
laryngeal artery, 602 
ligament of incus, 1061 
of malleus, 1160 
lingualis muscle, 399 
longitudinal fasciculus, 918 
sinus, 78, 130, 736 
maxillary bones, 105 
nerve, 1031 
region, muscles of, 376 
meatus of nose, 101, 144 
mediastinum, 1388 
medullary velum, 943 
mesenteric artery, 675 
plexus of nerves, 1085 
vein, 768 
nuchal line, 72 
obliquus oculi, muscle, 373 
occipital convolution, 877 
sulcus, 876 
olivary nucleus, 925 
ophthalmic vein, 740 
orbito-palpebral sulcus, 1137 
parietal convolution, 876 
peduncle of cerebellum, 910, 
943 
petrosal sinus, 742 
phrenic artery, 644 
veins, 767 
post-central sulcus, 875 
profunda artery, 655 
pubic ligament, 296 
pyloric artery, 673 
radio-ulnar articulation, 314 
ramus of ischium, 211 
of pubis, 213 
rectus oculi muscle, 373 
sacro-sciatic foramen, 294 
semicircular canal, 1165 
stephanion, 76 
superficial cerebellar veins, 736 
external pudic artery, 704 
surface of liver, 1327 
tarsal arch, 623 
temporal convolution, 877 
thoracic artery, 650 
thyroid artery, 601 
vein, 730 
transverse ligament, 302 
triangle of fourth ventricle, 945 
turbinated bone, 101 
crest, 117 
vena cava, 752 
vermiform process of cerebel- 
lum, 927 
vesical artery, 686 
plexus of veins, 761 
vocal cords, 1370 
Supernumerary bones, 103 
spleens, 1355 
Supinator longus muscle, 484 
radii brevis muscle, 487 
Supporting cells of Hensen, 1175 
Supra-acromial artery, 642 
nerves, 974 
Supracallosal gyrus, 887 
Supraclavicular glands, 787 
nerves, 974 
Supracondylar ridge, external, 
179 
Supracondylar ridge, internal,, 
180 
Supracondyloid glands of Leaf,. 
795 
Supraepitrochlear glands, 789 
Supraglenoid tubercle, 175 
Suprahyoid aponeurosis, 394 
artery, 603 
glands, lateral, 784 
median, 785 
region, muscles of, 393 
Supramandibular nerves, 1049 
Supramarginal convolution, 876* 
Supramastoid crest, 84, 137 
Supramaxillary lymphatic 
glands, 782 
nerves, 1049 
Suprameatal spine, 88 
triangle, 85 
Supraorbital arch, 80 
artery, 623 
foramen, 80, 140 
nerve, 1030 
notch, 80, 140 
ridge, 140 
vein, 726 
Suprapatellar bursa, 340, 518 
Suprarenal artery, 678 
capsule, 1428 
arteries of, 1431 
left, 1429 
lymphatic vessels of, 804 
lymphatics of, 1431 
nerves of, 1431 
relations of, 1428 
right, 1428 
structure of, 1430 
veins of, 1431 
glands, 1428 
accessory, 1430 
impression of liver, 1332 
plexus of nerves, 1084 
veins, 767 
Suprascapular artery, 641 
ligament, 302 
nerve, 983 
notch, 174 
Suprascleral lymph-space, 1104 
Supraspinales muscle, 421 
Supraspinatus fascia, 472 
muscle, 472 
Supraspinous fossa, 172 
ligament, 273 
Suprasternal artery, 642 
nerves, 974 
notch, 409 
space, 388 
Supratonsillar fossa, 1213 
Supratrochlear foramen, 181 
glands, 789 
nerve, 1030 
Supravaginal portion of uterus,. 
1488 
Surface form of abdominal aorta, 
670 
of acromio-clavicular artic- 
ulation, 301 
of ankle-joint, 351 
of axillary artery, 649 
of bladder, 1440 
of bones, 34 
of brachial artery, 654 
of carotid arteries, common, 
598 
external, 601 
of carpus, 204 
of clavicle, 170 
of common iliac arteries, 
682 
of dorsalis pedis artery, 715» 
of elbow-joint, 312 1594 
INDEX 
Surface form of external audi- 
tory meatus 1050 
iliac artery, 682, 695 
of eyelids, 1142 
of femoral artery, 701 
of femur, 229 
of fibula, 239 
of fifth nerve, 1041 
of foot, 255, 360 
of heart, 577 
of hip, 333 
of humerus, 183 
of hyoid bone, 154 
of inferior radio-ulnar artic- 
ulation, 317 
of internal iliac artery, 694 
of intestines, 1323 
of kidney, 1425 
of knee-joint, 343 
of lachrymal gland, 1143 
sac, 1143 
of liver, 1346 
of lungs, 1397 
of metacarpo-phalangeal ar- 
ticulation, 325 
of mouth, 1219 
of muscles of abdomen, 448 
of back, 424 
of face, 385 
of head, 385 
of lower extremity, 549 
of upper extremity, 500 
of vertebral region, 409 
of pancreas, 1353 
of parotid duct, 1215 
of patella, 231 
of pelvis, 220 
of plantar arteries, 720 
of popliteal artery, 709 
of radial artery, 658 
of radio-carpal articulation, 
318 
of radius, 192 
of rectum, 1323 
of scapula, 176 
of shoulder-joint, 307 
of skull, 147 
of spleen, 1359 
of sterno-clavicular articu- 
lation, 299 
-mastoid muscle, 391 
of sternum, 165 
of stomach, 1280 
of subclavian artery, 635 
of superior radio-ulnar ar- 
ticulation, 314 
* of temporo-mandibular ar- 
ticulations, 282 
of tibial artery, anterior,712 
posterior, 717 
of trachea, 1380 
of trifacial nerve, 1041 
of trigeminal nerve, 1041 
of ulnar artery, 661 
of vermiform appendix, 1323 
of vertebral column, 69 
Surgical anatomy of abdominal 
aorta, 670 
of abducent nerve, 1044 
of acromio-clavicular articu- 
lation, 301 
of ankle-joint, 351 
of arch of aorta, 592 
of artery of bulb, 691 
of ascending pharyngeal ar- 
tery, 611 
of auditory nerve, 1054 
of axilla, 645 
of axillary artery, 649 
vein, 748 
of azygos veins, 753 
Surgical anatomy of bend of 
elbow, 653 
of bile-duct, 1347 
of bladder, 1440 
of brachial artery, 654 
plexus, 991 
of carotid arteries, common, 
598 
external, 601 
internal, 621 
gland, 1049 
of carpus, 205 
of cavernous sinus, 740 
of cervical fascia, 389 
ganglion, 1077 
plexus, 977 
of cheeks, 1224 
of clavicle, 170 
of colon, 1326 
of common iliac arteries, 
682 
of conjunctiva, 1144 
of deep epigastric artery, 
697 
of descent of testicles, 1462 
of dorsalis pedis artery, 715 
of duodenum, 1325 
of ear, 1176 
of eighth nerve, 1054 
of elbow-joint, 312 
of eleventh nerve, 1063 
of emissary veins, 743 
of external iliac artery, 695 
of eye, 1134 
of eyelashes, 1143 
of eyelids, 1143 
of facial artery, 607 
nerve, 1049 
. veins, 726 
of fascia of femoral region, 
anterior, 515 
of femoral artery, 701 
of femur, 229 
of fibula, 239 
of foot, 256, 360 
of gall-bladder, 1347 
of glosso-pharyngeal nerve, 
1057 
of gums, 1224 
of hsemorrhoidal veins, 761 
of heart, 578 
of hernia, 1511 
of hip, 333 
of humerus, 183 
of hyoid bone, 154 
of hypoglossal nerve, 1066 
of inferior calcaneo-scaphoid 
ligament, 354 
thyroid artery, 641 
of innominate artery, 594 
of intercostal artery, 668 
nerves, 996 
of internal iliac arterv, 685, 
694 
jugular vein, 732 
mammary artery, 645 
pudic artery in male, 690 
of intestines, 1324 
of ischio-rectal region, 1535 
of kidney, 1425 
of knee-joint, 343 
of lachrymal gland, 1144 
sac, 1144 
of lateral sinus, 739 
of ligaments of vertebra,279 
of lips, 1224 
of lingual artery, 604 
of liver, 1346 
of lumbar plexus, 1017 
of lungs, 1397 
of lymphatic glands, 774 
Surgical anatomy of lymphatics 
of mammary gland, 814 
of neck, 787 
of upper extremity, 792 
vessels of peritoneum, 802 
of stomach, 806 
of male breast, 1509 
of mammary gland, 1508 
of maxillary artery, exter- 
nal, 607 
of Meibomian glands, 1143 
of membranes of cord, 836 
of middle meningeal artery, 
614 
of motor oculi nerve, 1025 
of mouth, 1224 
of muscles of acromial re- 
gion, 471 
of arm, 478 
of femoral region, anterior, 
518 
internal, 522 
posterior, 531 
of gluteal region, 528 
of iliac region, 511 
of lateral thoracic region, 
469 
of leg, 541 
of lower extremity, 551 
of orbital region, 375 
of palatal region, 406 
Of radio-ulnar region, an- 
terior, 484 
posterior, 491 
of tongue, 400 
of upper extremity, 503 
of nasal fossae, 1102 
of ninth nerve, 1057 
of occipito-frontalis muscle, 
368 
of oesophagus, 1230 
of olfactory nerve, 1021 
of optic nerve, 1022 
of ovary, 1503 
of palate, 1224 
of palatine artery, €15 
of palmar fascia, deep, 494 
of pancreas, 1353 
of patella, 231 
of pelvis, 220 
of penis, 1460 
of pericardium, 561 
of perinaeum, 1535 
of peritoneum, 1264 
of pharynx, 1224 
of phrenic nerve, 976 
of plantar arteries, 720 
fascia, 543 
of pleura, 1387 
of pneumogastric nerve, 
1062 
of popliteal artery, 709 
of pronator radii teres mus- 
cle, 479 
of prostate gland, 1452 
of prostatico-vesical plexus, 
762 
of radial artery, 658 
of radio-carpal articulation, 
318 
of radius, 192 
of rectum, 1325 
of salivary glands, 1224 
of saphenous veins, 757 
of scapula, 177 
of scrotum, 1469 
of seminal vesicles, 1476 
of seventh nerve, 1049 
of shoulder-joint, 307 
of sixth nerve, 1044 
of skull, 149 INDEX 
1595 
Surgical anatomy of spermatic 
cord, 1468 
veins, 766 
of spinal accessory nerve, 
1063 
of spleen, 1359 
of sternum, 165 
of sterno-clavicular artic- 
ulation, 299 
-mastoid muscle, 391 
of stomach, 1280 
of subclavian artery, 635 
of superficial fascia of cra- 
nial region, 367 
inguinal lymphatic glands, 
794 
■of superior radio-ulnar artic- 
ulation, 314 
of synovial tendons at wrist, 
492 
of tarsal joint, 356 
of tarsus, 256 
of temporal artery, 612 
of temporo-mandibular ar- 
ticulations, 282 
of tenth nerve, 1062 
of testicles, 1473 
of thoracic aorta, 666 
of thyroid artery, superior, 
603 
gland, 1405 
of tibia, 239 
of tibial artery, 717 
anterior, 712 
of tongue, 1093 
of tonsils, 1224 
of trachea, 1381 
of triangles of neck, 616 
of trochlear nerve, 1026 
of twelfth nerve, 1066 
of ulna, 192 
of ulnar artery, 661 
of ureter, 1428 
of urethra, male, 1445 
of utero-ovarian artery, 688 
of uterus, 1496 
of vermiform appendix, 
1325 
of vertebral artery, 639 
column, 69 
neck of humerus, 177 
of scapula, 172 
Suspensory ligament of axilla, 
464 
of clitoris, 437 
of eye, 1105 
of lens, 1129 
of liver, 1333 
of malleus, 1160 
of mamma, 463 
of ovary, 1501 
of penis, 437 
of Treitz, 1286 
muscle of duodenum, 1286 
Sustentacular cells of spleen, 1356 
fibres, 1121 
Sustentaculum lienis, 1259 
tali, 255 
Sutura, 264 
dentata, 264 
harmonia, 264 
limbosa, 264 
notha, 264 
serrata, 264 
squamosa, 264 
vera, 264 
Sutural bones, 103 
ligament, 259 
membrane, 264, 847 
Suture or sutures, basilar, 128 
coronal, 78, 127 
Suture or sutures, cranial, 126 
ethmo-frontal, 130 
-sphenoidal, 130 
frontal, 79, 127 
fronto-malar, 128 
-parietal, 127 
-sphenoidal, 128, 130 
intermaxillary, 139 
internasal, 139 
interparietal, 127 
lambdoid, 75, 78, 128 
masto-occipital, 75, 128 
-parietal, 128 
metopic, 83, 127 
naso-maxillary, 139 
occipito-parietal, 128 
petro-occipital, 75, 128, 133 
-sphenoidal, 128, 136 
-squamous, 88 
sagittal, 78, 127 
spheno-parietal, 128 
squamo-parietal, 128 
-sphenoidal, 128 
squamous, 85, 128 
transverse, 128 
facial, 128 
Sweat-glands, 1190 
Sylvian point, 866 
vein, superficial, 735 
Sylvius, aqueduct of, 912 
fissure of, 866, 884 
Svmington, ano-coccygeal body 
of, 1316 
Sympathetic nerve, 1066 
ganglion of, 1078 
plexuses of, 1080 
structure of, 1068 
Symphysis, 264, 267 
of jaw, 122 
sacro-coccygeal, 66 
Synarthrosis, 264 
Synchondrosis, 264 
Syndesmo-odontoid joint, 274 
Syndesmosis, 265 
Synovial bursa, 263 
ligaments, 262 
membranes, 262 
articular, 262 
bursal, 263 
of flexor tendon at wrist, 
492 
surgical anatomy of, 
492 
vaginal, 263. See also Indi- 
vidual joints. 
sheaths, 263 
villi, 262 
Systemic arteries, 583 
veins, 724 
T 
Tables of skull, 33 
Tabular portion of occipital bone, 
71 
Tactile corpuscle, 827 
Taenia fornicis, 896, 898 
hippocampi, 896 
pontis, 883 
semicircularis, 891, 894 
thalami, 904 
Tapetum of choroid, 1114 
lucidum, 1127 
nigrum, 1127 
Tarsal arch, 623 
artery, 715 
bones, development of, 253 
glands, 1139 
joint, surgical anatomy of, 356 
ligament, external, 370 
internal, 370 
Tarsal plates of eyelid, 1139 
Tarso-metatarsal articulations, 
357 
Tarsus, 242 
articulations of, 352 
surface form of, 255 
surgical anatomy of, 256 
synovial membrane of, 352 
Taste-buds, 1090 
Teeth, 1195 
arrangement of, 1198 
auditory, 1173 
bicuspid, 1138 
canine, 1197 
cementum of, 1204 
cortical substance of, 1204 
deciduous, 1196 
development of, 1204 
enamel of, 1203 
eruption of, 1208 
eye, 1197 
general characters of, 1195 
grinders, 1198 
incisors, 1196 
ivory of, 1202 
milk, 1196 
molar, 1198 
permanent, 1196 
superadded, 1208 
premolars, 1198 
roots of, 1196 
solid portion of, 1201 
stomach, 1197 
structure of, 1200 
surfaces of, 1195 
temporary, 1196 
Tegmen tympani, 87 
Tegmental region, subthalamic, 
885 
Tegmentum, 908 
of crus cerebri, 885 
fibres of, 908 
nucleus of, red, 908 
Tela chorioidea inferior, 856, 943 
superior, 854, 901 
subcutanea, 1180 
Temporal artery, 611 
anterior, 611, 640 
from internal maxillary, 614 
middle, 611 
posterior, 611, 640 
surgical anatomy of, 612 
bone, 83 
articulations of, 92 
attachment of muscles to, 
92 
development of, 91 
mastoid portion of, 85 
petrous portion of, 88, 136 
squamous portion of, 83 
convolution, 877 
crest, 76, 80, 84 
diploic vein, 734 
fascia, 381 
fossa, 76, 137 
horn of lateral ventricle, 890 
lines, 76, 80 
lobe, 885 
muscle, 382 
nerves, from auriculo-tempo- 
ral, 1038 
deep, 1037 
from facial, 1032, 1049 
ridges, 76, 80 
sulci, 868 
sulcus, first, 877 
fourth, 878 
inferior, 870 
second, 877 
third, 878 
veins, 727 1596 
INDEX 
Temporary teeth, 1196 
eruption of, 1209 
Temporo-facial nerve, 1032, 1049 
-malar filaments, 115 
foramen, 115 
nerve, 1032 
mandibular articulations, 280 
surface form of, 282 
surgical anatomy of, 282 
region, muscles of, 381 
-maxillary articulation, 138 
vein, 727 
sphenoidal lobe, 877 
Tendo Achillis, 535 
bursa of, 535 
oculi, 370 
Tendons, 363 
of diaphragm, central, 429 
cordiform, 429 
flexor, fibrous sheaths of, 545 
Tenon, capsule of, 1103 
Tensor fasciae femoris muscle, 515 
palati muscle, 404 
tarsi muscle, 371 
tympani muscle, 1161 
canal for, 1153 
Tenth nerve, 1057 
surgical anatomy of, 1062 
Tentorium, 900 
cerebelli, 850 
Teres major muscle, 474 
minor muscle, 473 
Testes gubernaculum, 1461 
muliebres of Galen, 1499 
Testicles, 1460, 1469 
coverings of, 1462 
descent of, 1461 
gubernaculum testis, 1461 
lobes of, 1472 
lymphatic vessels of, 804 
mediastinum testis, 1471 
parenchyma of, 1471 
rete testis, 1471 
sheaths of, proper, 1469 
size of, 1469 
structure of, 1471 
surgical anatomy of, 1473 
trabecula; of, 1471 
tubuli seminiferi of, 1471 
tunica albuginea, 1471 
vaginalis, 1470 
vasculosa, 1471 
tunics of, 1469 
weight of, 1469 
Testicular bag, 1462 
Thalamencephalon, 901 
Thalmic radiation, 905 
Thebesian valve, 567, 771 
Thigh, bones of, 221 
fascia of, 512 
muscles of, 512 
Third nerve, 1024 
ventricle of brain, 901 
Thoracic aorta, 665 
branches of, 666 
surgical anatomy of, 666 
artery, acromial, 651 
alar, 651 
long, 651 
superior, 650 
axis, 651 
cardiac nerves, 1061 
duct, 775 
structure of, 778 
ganglion, 1078 
nerves, 993 
plexus, 1079 
divisions of, anterior, 993 
posterior, 993 
long, 983 
posterior, 983 
Thoracic plexus, roots of, 993 
portion of gangliated cord, 
1078 
of oesophagus, 1226 
region, anterior, fascia of, deep, 
463 
superficial, 463 
muscles of, 463 
lateral, muscles of, 468 
surgical anatomy of, 469 
surface of lungs, 1391 
trachea, lymphatic vessels of, 
815 
vein, long, 748 
vertebrse, 53 
bodies of, 53 
laminse of, 54 
pedicles of, 54 
processes of, 54 
wall, lymphatic glands of, 810 
vessels of, 812 
Thoracico-epigastric vein, 748 
Thorax, 155 
boundaries of, 155 
cavity of, 556 
fasciae of, 424 
lymphatics of, 810 
muscles of, 424 
nerves of, cutaneous, 995 
openings of, lower, 556 
upper, 556 
veins of, 744 
Thumb, ligaments of, 321 
metacarpal bone of, 201 
muscles of, 484 
Thymic artery, 594 
lymphatic vessels, 815 
Thymus gland, 1407 
arteries of, 1408 
lobes of, 147 
lymphatics of, 1048 
nerves of, 1408 
structure of, 1408 
veins of, 1408 
Thyro-arytenoid ligament, infe- 
rior, 1370 
superior, 1370 
muscle, 1373 
-epiglottic ligament, 1367 
-epiglottideus muscle, 1373 
-glossal duct, 1090, 1401 
-hyals of hyoid bone, 154 
-hyoid ligaments, 1366 
membrane, 1366 
muscle, 392 
nerve, 1066 
Thyroid artery, inferior, 641 
surgical anatomy of, 641 
superior, 601 
surgical anatomy of, 603 
axis, 640 
body, 1401 
venous plexus on, 751 
cartilage, 1362 
foramen, 214 
ganglion, 1076 
gland, 1401 
accessory, 1403 
arteries of, 602, 1404 
color of, 1401 
isthmus of, 1403 
lobes of, 1403 
lymphatic vessels of, 782 
lymphatics of, 1405 
nerves of, 1405 
structure of, 1403 
surgical anatomy of, 1405 
veins of, 731. 1405 
weight of, 1401 
nerve, 1077 
notch, 1362 
Thyroid veins, accessory, 731 
inferior, 751 
middle, 730 
superior, 730 
Thyroidea ima artery, 594 
vein, 751 
Tibia, 233 
articulations of, 236 
attachment of muscles to, 236 
crest of, 234 
development of, 236 
lower extremity of, 235 
surfaces of, 235 
nutrient artery of, 719 
oblique line of, 235 
shaft of, 234 
surfaces of, 234 
spinous process of, 233 
structure of, 236 
surface form of, 236 
tubercle of, 234 
tuberosities of, 233 
upper extremity of, 233 
Tibial artery, anterior, 711 
branches of, 712 
peculiarities of, 712 
relations of, 711 
surface marking of, 712 
surgical anatomy of, 712 
posterior, 716 
branches of, 717 
peculiarities of, 717 
relations of, 716 
surface marking of, 717 
surgical anatomy of, 717 
recurrent, anterior, 713 
posterior, 713 
bursa, subcutaneous, 340 
gland, anterior, 795 
nerve, 1014 
anterior, 1016 
posterior, 1014 
veins, anterior, 758 
posterior, 758 
Tibialis anticus muscle, 532 
bursa of, 532 
posticus muscle, 538 
Tibio-fibular articulation, 345 
region, anterior, muscles of, 
531 
posterior, muscles of, 534 
-tarsal ligament, anterior, 347 
posterior, 347 
Tissue, adipose, pads of, 263 
areolar, subserous, 1245 
connective, subserous, 1246 
elastic, yellow, 261 
fibrous, white, 261 
intertubular, 1203 
Tomes's fibres, 1203 
granular sheath of, 1202 
Tongue, 1087 
anterior portion of, 1087 
apex or tip of, 1087 
arteries of, 1092 
base or root of, 1087 
body of, 1087 
corium of, 1089 
development of, 1242 
dorsum of, 1087 
fibrous septum of, 398 
fraenum of, 1087 
glands of, 1091 
-like lobe of liver, 1336 
lymphatics of, 1093 
lymphatic vessels of, 782 
margin of, 1087 
mucous membrane of, 1088 
muscles of, 398, 1092 
extrinsic, 398 
intrinsic, 398 INDEX 
1597 
Tongue, muscles of, surgical ana- 
tomy of, 400 
nerves of, 1093 
oral portion of, 1087 
papillae of, 1089 
pharyngeal portion of, 1087 
posterior portion of, 1087 
raph6 of, 1087 
structure of, 1088 
surface of, 1087 
surgical anatomy of, 1093 
veins of, 1092 
Tonsil, 1213 
arteries of, 1213 
of cerebellum, 931 
development of, 1243 
lingua, 1088 
lymphatics of, 1213 
nerves of, 1213 
pharyngeal, 1221, 1224 
surgical anatomy of, 1224 
veins of, 1213 
Tonsillar artery, 606 
nerves, 1057 
Tooth germ, 1206 
Torcular Herophili, 74, 737 
Trabeculae corpus cavernosum, 
1457 
of spleen, 1356 
of testicle, 1471 
Trachea, 1376 
arteries of, 641, 1380 
cartilages of, 1378 
fibrous membrane of, 1379 
lymphatics of, 1380 
mucous membrane of, 1380 
muscular fibres of, 1378 
nerves of, 1380 
relations of, 1376 
structure of, 1378 
surface form of, 1380 
surgical anatomy of, 1381 
thoracic, lymphatic vessels of, 
815 
veins of, 751, 1380 
Tracheal arteries, 641 
glands, 787, 1380 
veins, 751 
Trachelo-mastoid muscle, 419 
Tract of Burdach, 839, 843 
cerebellar, antero-lateral, as- 
cending, 842 
descending, 843 
direct, 843 
dorso-lateral, 843 
of cord, conducting, 841 
functions of, 844 
cornu, commissural, 844 
descending comma, 844 
crossed, 842 
of Goll, 839, 843 
of Gowers, 842 
of Helwig, triangular, 951 
lateral, of medulla, 945 
marginal, of Spitzka and Lis- 
sauer, 843 
nerve, afferent, 961 
ascending, 961 
descending, 959 
efferent, 959 
motor, 959 
sensory, 961 
olfactory, 880, 1019 
optic, 1021 
postero-lateral, 843 
-median, 843 
pyramidal, crossed, 842 
direct, 842 
uncrossed, 842 
septo-marginal, 844 
triangular, of Helwig, 843 
Tractus spiralis foraminosus, 89 
Tragicus muscle, 1147 
Tragus, 1145 
Transitional epithelium, 1428 
Transversalis cervicis muscle,419 
colli artery, 642 
muscle, 419 
fascia, 445, 1517 
humeri artery, 641 
muscle, 442, 1516 
relations of, 442 
Transverse cervical artery, 642 
colon, 1309 
flexure of, splenic, 1309 
diameter of pelvis, 217 
facial artery, 611 
suture, 128 
vein, 727 
fibres of cerebrum, 916 
of cord, 841 
of pons, 923 
foramen, 50 
humeral ligament, 305 
ligament of acetabulum, 330 
of atlas, 275 
inferior, 302 
of knee, 340 
superior, 302 
lingualis muscle, 399 
mesocolon, 1259, 1309 
metacarpal ligament, 324 
pelvic ligament, 459 
perineal artery, 691 
ligament, 459 
processes of a vertebra, 49 
sinus, 743 
of pericardium, 560 
suture, 128 
Transversus auriculae muscle, 
1147 
menti muscle, 378 
perinei superficialis muscle, 
457, 460 
Trapezium bone, 198 
articulations of, 198 
attachment of muscles to, 
198 
surfaces of, 198 
Trapezius muscles, 411 
Trapezoid bone, 198 
articulations of, 199 
surfaces of, 198 
ligament, 300 
ridge' 168 
Treitz, fossa of, 1260 
suspensory ligament of, 1286 
Triangle of elbow, 653 
of election, 617 
of fourth ventricle, 945 
Hesselbach's, 1520 
of necessity, 616 
of neck, anterior, 616 
posterior, 618 
surgical anatomy of, 616 
occipital, 618 
Petit's, 435 
Scarpa's, 516, 697 
subclavian, 618 
submaxillary, 394, 617 
suboccipital, 423 
suprameatal, 85 
Triangular cartilage of septum of 
nose, 1097 
fascia of abdomen, 437, 1155 
of urethra, 458 
interarticular fibro-cartilage, 
315 
muscles, 362 
tract of Helwig, 843, 951 
Triangularis menti muscle, 378 
sterni muscle, 425 
Triceps extensor cubiti muscle, 
477 
Tricuspid orifice, 567 
valve, 570 
Trifacial nerve, 1026 
surface marking of, 1041 
surgical anatomy of, 1041 
Trigeminal depression, 88 
nerve, 1026 
surface marking of, 1041 
surgical anatomy of, 1041 
Trigoid bodies, 820 
Trigone of bladder, 1438 
of habenula, 904 
Trigonum acustici, 945 
nervi hypoglossi, 945 
olfactorium, 881 
vagi, 945 
ventriculi, 890 
vesica;, 1438 
Tri-radiate sulcus, 874 
carotid, inferior, 616 
superior, 394, 617 
Trochanter, great, 223 
bursa of, 331 
lesser, 223 
rudimental, third, 224 
Trochanteric fossa, 223 
Trochlea of femur, 225 
of humerus, 181 
Trochlear fossa, 82 
nerve, 1025 
surgical anatomy of, 1026 
surface of astragalus, 244 
Trochoid, 265 
Trolard, anastomotic vein of, 735 
Troltsch, recessus of, 1162 
True vocal cords, 1370 
Trunk, arteries of, 665 
articulations of, 269 
fasciae of, 410 
muscles of, 410 
of pneumogastric nerve, gan- 
glion of, 1059 
Tube or tubes, bronchial, 1376 
Eustachian, 1153 
Fallopian, 1497 
lymphatic vessels of, 804 
medullary, 857 
neural, 857 
spiral, of Schachowa, 1419 
tonsil, 1155 
Tuber annulare, 922 
cinereum, 882 
Tubercle, acoustic, lateral, 950 
adductor, 225 
carotid, 51 
of cervical vertebra, anterior, 
•50 
posterior, 50 
Chassaignac's, 69 
conoid, 168 
comical, of Santorini, 1368 
cuneate, 941 
cuneiform, of Wrisberg, 1368 
of Darwin, 1145 
deltoid, 168 
egg, 1502 
of epiglottis, 1365 
of femur, 223 
genial, 123 
of hyoid bone, 153 
infragleniod, 174 
jugular, 74 
lachrymal, 109 
mental, 122 
of navicular bone, 246 
olfactory, 881, 1019 
of optic thalamus, anterior, 904 
peroneal, 243 
pharyngeal, 73 1598 
INDEX 
Tubercle, pterygoid, 97 
of quadratus, 225 
of ribs, 161 
of Rolando, 941 
of scaphoid, 196 
supraglenoid, 175 
of tibia, 234 
of ulna, 186 
of zygoma, 84 
Tubercula quadrigemina, 911 
Tuberculum acusticum, 945,1051 
caudatum, 1333 
impar, 1242 
Tuberosity, bicipital, 195 
of calcaneus, 243 
of cuboid, 245 
of femur, inner, 226 
outer, 226 
glenoid, 175 
of humerus, 179 
of ischium, 211 
maxillary, 106 
of navicular bone, 246 
of palate bone, 117, 135 
of radius, 190 
of ribs, 161 
of sacrum, 63 
of scaphoid bone, 246 
of tibia, external, 233 
internal, 233 
Tubuli, lactiferi, 1507 
seminiferi, 1471 
uriniferi, 1418 
Tunic of Ruysch, 1113 
Tunica adventitia, 1228 
albuginea, 373, 1457, 1471 
interna, 1120 
propria, 1180 
vaginalis, 1462, 1465, 1469 
cavity of, 1470 
parietal portion of, 1470 
visceral portion of, 1470 
vasculosa testis, 1471 
Tunics of eye, 1107 
of testicle, 1469 
Turbinated bone, inferior, 119 
articulations of, 120 
development of, 120 
surfaces of, 120 
middle, 101 
sphenoidal, 143 
superior, 101 
crest, 107, 117 
Turek, fasciculus of, 842 
Turner, intraparietal sulcus of, 
875 
Twelfth nerve, 1064 
surgical anatomy of, 1066 
Tympanic antrum, 87 
aperture, 1151 
artery from ascending pharyn- 
geal, 610 
from internal carotid, 622 
maxillary, 613 
attic, 87 
cavity, 1150 
nerve, 1056 
from facial, 1047 
plexus of, 1057 
sulcus, 1149 
Tympanohyal process, 92 
Tvmpanoinalleolar ligaments, 
1156 
Tympanum, 1150 
arteries of, 1162 
cavity of, 1150 
floor of, 1151 
fundus of, 1151 
mucous membrane of, 1162 
muscles of, 1161 
nerves of, 1163 
Tympanum, ossicles of, 1158 
pyramid of, 1153 
roof of, 1151 
veins of, 1163 
walls of, 1153 
U 
Ulna, 184 
articulations of, 189 
attachment of muscles to, 189 
development of, 189 
lower extremity of, 189 
shaft of, 188 
structure of, 189 
surface form of, 189 
surgical anatomy of, 192 
tubercle of, 186 
upper extremity of, 184 
coronoid process of, 186 
olecranon process of, 186 
sigmoid cavities of, 186 
Ulnar artery, 660 
peculiarities of, 661 
surface marking of, 661 
surgical anatomy of, 661 
groove, 182 
nerve, 988 
region, muscles of, 498 
veins, 745 
Umbilical arteries in foetus, 579, 
685 
fissure of liver, 1331 
fossa of liver, 1331 
notch, 1331 
region, contents of. 1234 
Umbilicus, lymphatic vessels of, 
802 
Umbo, 1157 
Unciform bone, 199 
articulations of, 200 
attachment of muscles to, 
200 
process of ethmoid, 100 
Uncinate convolution, 879 
fasciculus, 917 
process of Winslow, 1348 
Uncrossed pyramidal tract, 842 
Uncus, 879 
Ungual phalanges, 204 
Unipolar cells, 820 
Unstriated muscle, 361 , 
Unstriped muscle, 361 
Upper deep cervical glands, 786 
extremity, arteries of, 631 
articulations of, 297 
bones of, 167 
fascise of, 462 
lymphatic glands of, 788 
vessels of, 792 
muscles of, 462 
veins of, 744 
subscapular nerve, 984 
Urachus, 1435 
fold of, 1519 
Ureter, 1426 
arteries of, 1428 
fibrous coat of, 1427 
Ureteral folds, 1439 
Ureters, lymphatic vessels of,804 
muscular coat of. 1428 
mucous coat of, 1428 
nerves of, 1428 
orifices of, 1438 
relations of, 1427 
structure of, 1427 
surgical anatomy of, 1428 
Urethra, female, 1446 
lymphatic vessels of, 803 
mucous coat of, 1446 
Urethra, female, muscular coat 
of, 1446 
orifice of, 1481 
structure of, 1446 
submucous coat of, 1446 
male, 1441 
bulb of, 1458 
cavernous portion of, 1443 
crest of, 1442 
fossa navicularis of, 1444 
lymphatic vessels of, 803 
membranous portion of, 
1442 
mucous coat of, 1444 
muscular layer of, 1445 
portion of, 1442 
pendulous portion of, 1443 
penile portion of, 1443 
prostatic portion of, 1441 
spongy portion of, 1443 
structure of, 1444 
submucous tissue of, 1445 
surgical anatomy of, 1445 
Urinary bladder. See Bladder, 
organs, 1411 
Uterine artery, 687 
portion of Fallopian tube, 
1497 
plexus of nerves, 1086 
veins, 763 
plexus of, 763 
Utero-sacral ligaments, 1490 
-vaginal plexus, 1086 
-vesical fold, 1490 
pouch, 1487, 1490 
Uterus, 1486 
abnormalities of, 1493 
after parturition, 1494 
appendages of, 1497 
arbor vita? of, 1492 
arteries of, 1494 
bicornate, 1493 
body of, 1487 
cavity of, 1491 
changes induced bv pregnancy 
1493 
at menstrual period, 1493 
at different ages, 1493 
folds of, 1489 
fundus of, 1487 
ganglia of, 1086 
ligaments of, 1489 
lymphatic vessels of, 803, 1495 
masculinus, 1442 
mucous membrane of, 1492 
muscular coat of, 1491 
neck of, 1488 
nerves of, 1086, 1496 
structure of, 1491 
supravaginal portion of, 1488 
surgical anatomy of, 1496 
vaginal portion of, 1488 
veins of, 1495 
Utricle of vestibule, 1169 
Uvea, 1118 
Uvula of cerebellum, 931 
of throat, 1211 
vesica?, 1439 
V 
Vagina, 1483 
arteries of, 1485 
azygos arteries of, 687 
columns of, 1484 
erectile tissue of, 1485 
lymphatic vessels of, 804, 1485 
mucosa intertubercularis, 304 
membrane of, 1484 
muscular coat of, 1484 
nerves of. 1485 INDEX 
1599 
Vagina, orifice of, 1481 
relations of, 1484 
rugae of, 1484 
'structure of, 1484 
veins of, 1485 
vestibule of, 1481 
Vaginal artery, 687 
bulb, 1483 
fornix, 1484 
plexus of nerves, 1086 
portion of uterus, 1488 
process of temporal bone, 89 
synovial membrane, 263 
veins, 763 
plexuses of, 763 
Vagus nerve, nuclei of, 950 
Valentin, ganglion of, 1033 
Vallecula of cerebellum, 926 
epiglottica, 1365 
Sylvii, 856 
Valley of cerebellum, 926 
Valsalva, sinuses of, aortic, 573 
pulmonary, 571 
Valve or valves, anal, 1319 
of Bauhin, 1308 
bicuspid, 572 
coronary, 567 
Eustachian, 567 
in foetus, 578 
of Gerlach, 1303 
of Guerin, 1444 
of Hasner, 1142 
Houston's, 1318 
ileo-csecal, 1308 
of Kerkring, 1291 
of Morgagni, 1319 
pyloric, 1272 
rectal, 1318 
semilunar, 1319 
aortic, 572 
pulmonic, 571 
Thebesian, 567, 771 
tricuspid, 570 
of Vieussens, 910, 933 
Valvula; conniventes, 1291 
Vas deferens, 1472 
artery of, 686 
lymphatic vessels of, 804 
structure of, 1473 
spirale, 1173 
Vasa brevia arteries, 674 
intestini tenuis artery, 675 
vasorum of arteries, 586 
Vascular papillae, 1181 
system at birth, changes in, 
581 
in foetus, 578 
Vasomotor nerves, 1071 
Vastus extemus muscle, 517 
intern us muscle, 517 
Vater, ampulla of, 1345 
corpuscles of, 828 
Veins, 721 
of abdomen, 755 
anastomotic, of Troland, 735 
angular, 726 
appendicular, 768 
of arm, 744 
auricular, 727 
axillary, 747 
azygos, 752 
larger, 752 
left lower, 753 
upper, 753 
right, 752 
smaller, 753 
bacilar, 735 
basilic, 746 
median, "746 
brachial, 747 
hrnchin-eenhalie 7KO 
Veins of bones, 41 
bronchial, 753 
buccal, 726 
cardiac, 770 
cava, inferior, 764 
superior, 752 
cephalic, 747 
median, 746 
cerebellar, 736 
cerebral, 734 
cervical, anterior, deep, 733 
posterior, deep, 733 
choroid, 735 
circumflex, iliac, 759 
superficial, 756 
companion, 747 
coronary, 768 
costo-axillary, 748 
cystic, 769 
digital, hand, 745 
of diploe, 733 
dorsal, of penis, 762 
dorsi-spinal, 753 
of dura mater of brain, 849 
emissary, 743 
emulgent, 766 
epigastric, deep, 759 
superficial, 756 
of face, exterior of, 725 
facial, 726 
femoral, 758 
of fingers, superficial, 745 
of foot, 758 
frontal, 725 
of Galen, 735 
gastric, 768 
gluteal, 761 
hjemorrhoidal, external, 76( 
inferior, 760 
middle, 760 
superior, 768 
of hand, superficial, 745 
of head, 724 
of heart, 577 
hepatic, 767 
histology of, 722 
hypogastric, 760 
iliac, circumflex, deep, 759 
common, 764 
external, 759 
internal, 760 
ilio-lumbar, 764 
innominate, 750 
intercostal, 752 
interosseous, of forearm 747 
intervertebral, 755 
intralobular, 767 
jugular, 728 
laryngeal, inferior, 751 
lingual, 729 
longitudinal, inferior 738 
of lower extremity, 755 
lumbar, 765 
ascending, 753, 765 
right, 752 
mammary, internal, 750 
masseteric, 726 
maxillary, internal, 7-7 
median, 745 
medulli-spinal, 755 
meningeal, 730, 734 
meningo-rachidian, 75-r 83 ■ 
mesenteric, 768 
naso-frontal, 740 
of neck, 725 
obturator, 761 
occipital, 727 
oesophageal, 751 
ophthalmic, 740 
orbital, 727 
ovarian 766 
Veins, palatine, 727 
palmar, deep, 747 
pancreatic, 769 
of pelvis, 755 
peroneal, 758 
pharyngeal, 730 
phrenic, 767 
of pia mater of brain, 856 
plantar, 758 
plexus of, palmar, 745 
pampinniform, 765 
pharyngeal, 730 
prostatic, 761 
prostatico-vesical, 761 
pterygoid, 727 
spermatic, 765 
spinal, 753 
on thyroid body, 751 
uterine, 763 
vaginal, 763 
vesical, inferior, 763 
superior, 761 
popliteal, 758 
portal, 769 
system of, 768 
profunda femoris, 759 
pterygoid plexus, 727 
pudic, 760 
pulmonary, 723 
pyloric, 768 
radial, 745 
deep, 747 
ranine, 729 
renal, 767 
sacral, lateral, 760 
middle, 764 
saphenous, 756 
sciatic, 761 
spermatic, 765 
spinal, 753 
splenic, 768 
stylo-mastoid, 725 
subclavian, 749 
sublobular, 767 
submaxillary, 727 
submental, 727 
supraorbital, 726 
suprarenal, 767 
sylvian, superficial. 735 
systemic, 724 
temporal, 727 
temporo-maxillary, 727 
thoracic, long, 748 
thoracico-epigastric, 748 
of thorax, 744 
thyroid, accessory, 731 
gland, 731 
inferior, 751 
midd^., 730 
superior, 730 
thyroidea ima, 751 
tibial, 758 
tracheal, 751 
ulnar, 745 
of upper extremity, 744 
uterine, 763 
vaginal, 76" 
vuntriei.lar, 735 
vermiaa, 735 
of vert-bra. bodies of, 755 
vertebral, 732, 751 
Vidum. 730 
Velum interpositum, 854, 901. 
m.dullary, 943 
pendulum palati, 1211 
Vena azygos major, 752 
minor, 753 
basis vertebrae, 49, 755 
cava, ascending, 764 
inferior, 764 
peculiarities of. 764 1600 
INDEX 
Vena cava, superior, 752 
magna Galeni, 735 
Venae basis vertebrarum, 755 
comites, 723, 747 
corporis striati, 735 
interlobulares of kidney, 1'1 
Thebesii, 771 
vorticosae, 1113 
Venesection, 746 
Venous arch, nasal, 725 
plexus, interspinous, 732 
on thyroid body, 751 
Venter ilii, 209 
of scapula, 171 
Ventral auditory nuclei, 950 
root of eighth nerve, 1050 
of spinal nerve, 965 
Ventricle of Arantius, 944 
of brain, fifth, 897 
fourth, 943 
third, 901 
Verga's, 896 
of heart, fibres of, 575 
left, chordae tendineie of, 
columnae carneae of, 57 
right, 568 
chordae tendineae of, 5' 
columnae cameae of, 57 
of larynx, 1371 
lateral, 888 
Ventricular gray matter, 922 
portion of heart, 568 
veins, 735 
Ventro-median fissure, 837 
Verga's ventricle, 896 
Vermian vein, 735 
Vermiform appendix, 1303 
arteries of, 1305 
canal of, 1304 
lymphatics of, 1306 
mesentery of, 1260 
mucous membrane of, 15 
muscular coat of, 1305 
serous coat of, 1304 
structure of, 1304 
submucous coat of, 1305 
surface form of, 1323 
surgical anatomy of, 132 
veins of, 1306 
process of cerebellum, 926 
Vertebrae, 48 
bodies of, veins of, 7 55 
centrum of, 48 
oervi. al, 49 
evonth, 53 
coccy/eal, 61 
deveio. ».nent of. 58 
dorsal, 53 
false 61 
general characters of, 48 
immovable, 61 
ligament of, 270 
lumbar, . 6 
prwessof, -rtieular, 49 
spinous '9 
transverse. 49 
prominent, 53 
sacral, 61 
structure of, 58 
thoracic, 53 
Vertebral aponeurosis, 411, 1 
artery, 637 
surgical anatomy of,'139 
border of scapula. 171 
canal, 49 
column, 48 
artio'dation.* of, 269 
surface form of, 69 
surgical anatomy of, 69 
foramen, 49 
■groove, 155 
Vertebral, ligaments of, 270 
plexus of nerves, 1077 
region, anterior, muscles of, 406 
lateral, muscles of, 408 
muscles of, 409 
ribs, 160 
vein, 732, 751 
Vertebrarterial foramen, 50 
Vertebro-chondral ribs, 160 
-pericardial ligaments, 558 
-pleural ligament, 1385 
-sternal ribs, 159 
Vertex of skull, 129 
Vertical lingualis muscle, 399 
plate of palate bone, 117 
Verumontanum, 1442 
Vesical arteries, 686 
plexus of nerves, 1086 
of veins, inferior, 762 
superior, 761 
trigone, 1438 
Vesicle, prostatic, 1442 
Vesicles, Graafian, 1502 
seminal, 1475 
Vesico-uterine ligament, 1490 
Vesicula prostatica, 1441 
Vesicular column of Clark, 846 
Vestibular artery, 1176 
ganglion, 1053 
nerve, 1053 
path, 1054 
root of eighth nerve, 1050 
window, 1152 
Vestibule, aortic, of Sibson, 572 
of ear, 1164 
of mouth, 1194 
of nose, 1099 
of vagina, 1481 
Vestigial fold of pericardium, 561 
Vibrissae, 1096 
Vicq d'Azyr, bundle of, 883 
Vidian artery, 616 
canal, 96, 135 
nerve, 1034 
veins, 730 
Vieussens, ansa of, 1076 
centrum ovale majus of, 881 
valve of, 910, 933 
Villi of small intestine, 1292 
synovial, 262 
Viscera, development of, 1235 
Visceral cranium, 71 
layer f pleura, 1382 
> v ■».] ' itics, 811 
peritoneum, 1247 
po lion of tunica vaginalis, 
1470 
surfae* of liver, 1329 
of s omach, 1270 
\ is ::d -is, 1106 
c nl < i, 1022 
ourpb , 1120 
\ ' - body, 1129 
him >r of eye, 1129 
f skull, 34 
\ >i al cords, false, 1370 
trm , 1370 
■ s, 1365 
\ oic organs of, 1361 
\ ilkmann's canals, 38 
\ 'luntary muscle, 361 
Vomer, ! 20 
- v of 121, 143 
u ticulations of, 122 
development of, 122 
-urf- c< s of, 121 
• crii cartilage, 1097 
Vortex of heart, 575 
Vulva, fossa navicularis of, 
1478 
Vulvo-vaginal gland, 1482 
w 
Waldeyer, gem ■ < ;>• 
of, 1501 
odontoblasts o 
Wedge bones, 24 
-shaped funicui 
Wharton's duct, 
White commissun 
fibrous tissue, 
line of Hilton, 131.) 
matter of cerebellum, 931 
of cerebrum, 913 
nerve fibres, 822 
substance of cord, 841 
of Schwann, 822 
Willis, circle of, 629, 640 
Winslow, accessory anterior cru- 
ral nerve of, 1004 
ligament of, posterior, 335 
uncinate process of, 1348 
Wirsung, canal of, 1351 
Womb, 1486 
Worm of cerebellum, 926 
Wormian bones, 103 
development of, 103 
Wrisberg, cardiac ganglion of, 
1081 
cartilages of, 1365 
cuneiform tubercle of, 1368 
ligament of, 339 
nerve of, 986 
pars intermedia of, 1045 
Wrist, articulations of, 317 
bursa of, 492 
-joint, 317 
ligament of, 318 
surface form of, 318 
surgical anatomy of, 318 
X 
Xipho-pericardial ligament, 
559 
Xiphoid appendix, 158 
surfaces of, 158 
cartilage, 155 
Y 
Y-LIG AMENT, 328 
Yellow elastic tissue, 261 
spot of Sommerring, 1121 
Z 
Zinn, ligament of, 373 
zonule of, 1129 
Zona arcuata, 1173 
fasciculata, 1430 
glomerulosa, 1430 
incerta, 910 
orbicularis, 327 
pectinata, 1173 
reticularis, 1430 
tecta, 1173 
Zonula ciliaris, 1129 
Zonule of Zinn, 1129 
Zygoma, 84 
Zygomatic arch, 138 
fossa, 138 
lymphatic glands, 782 
process of malar, 115 
of temporal bone, 84 
Zygomaticus major 'ouscle, 377 
minor musch, 377 
Zymogen granules, 1352