m ^:- v.* -^ ^ • *€■■'■ w -^*3te4 a&. H/< >' -m ,y^ q)]i||.)j; i5>\V° / ' if [ -.A* ',' 24. /A L1BRAKY OF THE MASS. HED. COLLEGE. Rules and Regulations. 1. Students attending any of the Lectures in the ivln..jachusetts Medical College may take books from the Library during the course, by depositing Five Dollars with the Dean; and the students of any of the Medical Professors may have the same privilege on the same terms throughout the year. 2. The Library shall be open on the afternoon ol every Saturday, from 3 to 5 o'clock, for the de- livery and return of books. 3. Three volumes may be taken at a time, and kept four weeks, or returned sooner if desired.— Twenty-five cents a week will be charged for each volume that is kept beyond that time ; and when a fine is incurred, it must be paid before any more books can be taken out. 4. All the books must be returned on or before the last Wednesday in February, and on or. before the first Wednesday in August, preparatory to the semi-annual examinations of the Library. 5. if a volume be lost, or injured, the price of the book, or the amount necessary to repair the injury, as the case may be, will be deducted from the sum deposited; otherwise the whole amount will be returned to the depositor, when he ceases to use the Library. " jJjlBL i Sedurn,......\^, J...)cJ^sJ\.-^^J N„/0C2/ 5 A :*| THE LONDON DISSECTOR Printed by T. & G. Palmer. / FINL/r AND HOPKINS' ED1V10N. t THE LONDON DISSECTOR "^ OR SYSTEM OF DISSECTION PRACTISED IN The Hospitals and Lecture Rooms of the Metropolis; EXPLAINED BY THE CLEAREST RULES, FOR THE USE OF STUDENTS: COMPRISING A Description of the Muscles, Vessels, Nerves, and Viscera of the Human Body, as they appear on Dissection; With Directions for their Demonstration. FIRST AMERICAN, FROM THE LAST LONDON EDITION. To which is added, AN APPENDIX, CONTAINING THE RUYSCHIAN ART AND METHOD OF MAKING PREPARATIONS TO EXHIBIT THE STRUCTURE OF THE HUMAN BODY, Illustrated with a Representation of the Quicksilver Tr:r. anil its Appendages. ..^ GEflX?>* 'flfOtloVi PHILADELPHIA, 7 PUBLISHED BY A. FINLEY AND W. H. HOPKINS. 1810. ~ PREFACE. 1HE writer of the following pages, having frequently witnessed the diffi- culties which attend the pursuit of Practical Anatomy, conceived that some assistance might be derived from a Compendium, describing the various parts of the human body as they come into view under the knife of the dissec- tor. With this intention the present performance is offered to the public. The muscles are demonstrated in the order of their situation, this being the only method that can be pursued in actual dissection. a 2 VI PREFACE. The relative situation of the several parts is minutely attended to, and, at the same time, repetitions are avoided, as far as the nature of the arrangement adopted would allow. Should this work in any degree facilitate the pro- gress of the anatomical student, the ob- ject of the author will be attained. CONTENTS. Page GENERAL Rules for Dissection 1 Chap. I. Dissection of the Abdomen. Sect. I. Muscles of the Abdomen 5 Obliquus Descendens Externus ib. Obliquus Ascendens Internus 11 Cremaster 13 Transversalis Abdominis 14 Fascia Transversalis 15 Rectus Abdominis 16 Pyramidalis 17 Sect. II. Dissection of the Cavity of the Ab- domen 17 General Situation of the Viscera 18 Peritoneum, and its Reflections ib. Liver 20 Gall-bladder 22 Stomach 23 Intestines ib. Spleen 26 Pancreas ib. Kidneys 27 V11I Page Chap. I. Renal Capsules 28 Diaphragm ib. Psoas Parvus 30 Psoas Magnus 31 Iliacus Internus ib. Fascia Iliaca 32 Quadratus Lumborum ib. Of the vessels and nerves situated behind the peritoneum 33 Aorta and its ramifications ib. Vena Cava Abdominalis 39 Vena Portarum 40 Par Vagum ib. Anterior Intercostal Nerve ib. Posterior Intercostal 41 Thoracic duct ib. Chap. II. Dissection of the Perineum and Or- gans of Generation in the Male. General Remarks 42 Erector Penis 43 Accelerator Urinae 44 Transversus Perinei 45 Sphincter Ani 46 Levator Ani ib. Coccygeus 47 Connection of the Bladder and Rectum 48 Prostate Gland ib. Urethra ib. Corpus Spongiosum, and Bulb of the Urethra 49 Glandule Anteprostatse ib. Vesiculse Seminales ib. Vasa Deferentia ib. Corpora Cavernosa Penis 50 Bladder ib. Rectum, Sec, 51 IX Page Chap. II. Vessels and Nerves contained within the Pel- vis 52 Internal Iliac Artery and Branches ib. Internal Iliac Vein and its Branches 54 Nerves of the Pelvis ib. Course of the Anterior Crural Nerve ib. Course of the Obturator Nerve 55 Course of the Great Sciatic Nerve ib. Of the Scrotum ib. Chap. III. Dissection of the Organs of G ration in the female. ENE- Mons Veneris 56 Labia Externa 57 Clitoris ib. Perineum ib. Nymphs 58 Vestibulum ib. Hymen, and Caruncul* Myrtiformes ib. Vagina and Os Tincse 59 Erector Clitoridis 60 Transversus Perinei ib. Sphincter Vaginae 61 Sphincter Ani ib. Levator Ani ib. Coccygeus ib. Plexus Retiformis ib. Vagina ib. Uterus 62 Fallopian tubes ib. Ovaria 63 Bladder ib. Urethra ib. Ureter ib. Chap, , IV. Dissection of the Thigh. Sect. I. Of the Anterior Part of the Th: [GH. X Page Chap. IV. § 1. Of the Fascia of the Thigh, Cutaneous sels and Nerves, &c. 64 § 2. Muscles situated on the Fore-part and Inside of the Thigh 67 Tensor Vaginx Femoris Jb. Sartorius ib. Rectus Femoris 68 Vastus Externus 69 Vastus Internus 70 Cruralis 71 Gracilis 72 Pectinalis ib. Triceps Adductdr Femoris 73 § 3. Of the Vessels and Nerves situated on the Fore-part and Inside of the Thigh 75 Femoral Artery and its Branches ib. Obturator Artery 78 Femoral Vein ib. Obturator Vein ib. Anterior Crural Nerve ib. Obturator Nerve 79 Sect. II. Of the Posterior Part of the Thigh. § 1. Of the Fascia, &c. 79 § 2. Of the Muscles on the Back-part of the Thigh 80 Gluteus Maximus ib. Gluteus Medius 81 Gluteus Minimus 82 Pyriformis 83 Gemini 84 Obturator Internus ib. Quadratus Femoris 85 Obturator Externus 86 Biceps Flexor Cruris ib. Semitendinosus 87 XI Page Chap. IV. Semimembranosus 88 § 3. Of the Vessels and Nerves on the Posterior Part of the Thigh 89 Arteria Glutea ib. Arteria Sciatica ib. Veins 90 Nervus Sciaticus ib. Sect. III. Dissection of the Ham and Fascia on the Back-part of the Leg 91 Of the Fascia ib. Sciatic Nerve ib. Popliteal Vein ib. Popliteal Artery 92 Chap. V. Dissection of the Leg and Foot. Sect. I. Of the Fore-part of the Leg and Foot 94 Of the Fascia, Cutaneous Vessels, and Nerves, 8cc. ib. Of the Muscles situated on the Fore-part and Outside of the leg 95 Tibialis Anticus 'ib. Extensor Longus Digitorum Pedis 96 Peroneus Tertius 97 Extensor Proprius Pollicis Pedis ib. Peroneus Longus 98 Peroneus Brevis 99 Of the Muscles on the Upper Part of the Foot 100 Extensor Brevis Digitorum Pedis ib. Of the Vessels and Nerves situated on the Fore-part of the Leg and Foot 101 Anterior Tibial Artery ib. Anterior Tibial Vein 103 Anterior Tibial Nerve ib. Sect. II. Dissection of the Posterior Part of the Leg. Muscles situated on the Posterior Part of the Leg 104 XII Page Chap. V. Gastrocnemius Externus, seu Gemellus 104 Soleus 105 Plantaris 106 Popliteus 107 Flexor Longus Digitorum Pedis 108 Flexor Longus Pollicis Pedis 109 Tibialis Posticus ib. Vessels and Nerves of the Back-part of the Leg 111 Posterior Tibial Artery, and Ramifica- tions ib. Posterior Tibial Vein 113 Posterior Tibial Nerve ib. Sect. III. Dissection of the sole of the foot 114 Aponeurosis Plantaris ib. First order of Muscles in the Sole of the Foot ib. Abductor Pollicis Pedis 115 Abductor Minimi Digiti Pedis ib. Flexor Brevis Digitorum Pedis ib. Second Order of Muscles in the Sole of the Foot 116 Tendon of the Flexor Digitorum Longus ib. Tendon of the Flexor Longus Pollicis ib. Flexor Digitorum Accessorius 117 Lumbricales Pedis ib. f Third Order of Muscles in the Sole of the Foot i ib. Flexor Brevis Pollicis Pedis ib. Adductor Pollicis Pedis 118 Flexor Brevis Minimi Digiti ib. Transversalis Pedis ib. Tendon of the Tibialis Posticus 119 Fourth Order of Muscles in the Sole of the Foot ib. Xlll Page Chap. V. Tendon of the Peroneus Longus 119 Interossei Interni 120 Interossei Externi ib. Chap. VI. Dissection of the Head. Sect. I. Of the External Parts of the Head 121 Integuments ib. Occipito-frontalis ib. Muscles of the Ear 122 1. Common:— Attollens Aurem ib. Anterior Auris ib. Retrahentes Auris ib. 2. Proper :— Helicis Major 123 Helicis Minor ib. T ragicus ib. Antitragicus ib. Transversus Auris 124 3. Internal:— Laxator Tympani ib. Tensor Tympani 125 Stapedius ib. Sect. II. Of the Contents of the Cranium. or of the Brain and its Mem- i branes 126 Dura Mater ib. Pia Mater 129 Cerebrum 130 Cerebellum 138 Medulla Oblongata, and Nerves of the Brain 144 Medulla Spinalis, and Nervi Spinales 146 Course of the Great Sympathetic Nerve 149 Course of the Par Vagum ib. b xiv Page Chap. VI. Vessels of the Brain 150 Chap. VII. Dissection of the Anterior Part of the Neck. Of the Muscles 152 Playtsma Myoides 153 Sterno-cleido-mastoideus ib. Os Hyoides, Larynx, Trachea 154 Sterno-hyoideus 155 Omo-hyoideus ib. Sterno-thyroideus 156 Thyro-hyoideus ib. Crico-thyroideus 157 Digastricus - ib. Stylo-hyoideus 158 Stylo-glossus ib. Stylo-pharyngeus 159 Mylo-hyoideus ib. Genio-hyoideus 160 Genio-hyo-glossus 161 Hyo-glossus ib. Lingualis ib. Sect. II. Of the Vessels and Nerves seen in the Dissection of the Neck 162 Carotid Artery and its Ramifications ib. Internal Jugular Vein and its Branches 164 Eighth Pair of Nerves, or Par Vagum 165 Intercostal, or Great Sympathetic Nerve 166 Ninth Pair, or Lingual Nerve 167 Lingual Branch of the Fifth Pair 168 Spinal Accessory Nerve ib. Cervical Nerves ib. Phrenic Nerve ib. Recurrent Nerve 169 Chap.VIII.Dissection of the Thorax. Sect. I. Of the Muscle s which lie upon the outside of the Thorak 169 XV Page €hap. VIII. Pectoralis Major 170 Pectoralis Minor 171 Subclavius ib. Sect. II. Of the Parts contained within the Cavity of the Thorax 172 General Appearances ib. Pleura 173 Lungs 174 Pericardium ib. Heart ib. Sect. IH. Of the Great Vessels of the Heart 176 Vena Cava Superior ib. Vena Cava Inferior 177 Aorta and Ramifications ib. Thymus 178 Course of the Subclavian Artery and tys Branches ib. Course of the Subclavian Vein 180 Course of the Brachial Plexus of Nerves 181 Scalenus Anticus ib. Scalenus Medius ib. Scalenus Posticus 182 Sect. IV. Dissection of the Axilla, or Arm-Pit ib. Axillary Vein 183 Axillary Artery 184 Axillary Plexus of Nerves 185 Sect. V. Dissection of the Posterior Me- diastinum, and of the Nerves and Vessels which have their Course through the Thorax 187 Course of the Phrenic Nerve through the Thorax ib. Trachea ib. XVI Page Chap. VIIL Course of the Intercostal,or Gi'eatSym- pathetic Nerve 188 Vena Azygos 189 Aorta, and its Ramifications in the Tho- rax ib. Thoracic Duct 190 OEsophagus 191 Course of the Par Vagum in the Thorax 194 Dorsal Nerves ib. Sect. VI. Dissection of the Heart, when removed from the body 193 Chap. IX. Dissection of the Face. Sect. I. Of the Muscles 197 Orbicularis Palpebrarum ib. Corrugator Supercilii 198 Compressor Naris ib. Levator Labii Super ioris Atoeque Nasi 199 Zygomaticus Minor 200 Zygomaticus Major ib. Levator Anguli Oris 201 Depressor Anguli Oris ib. Depressor Labii Inferioris ib. Buccinator 202 Orbicularis Oris 203 Depressor Labii Superioris Aheque Nasi ib. Levator Labii Inferioris 204 Masseter ib. Temporalis 205 Pterygoideus Externus 206 Pterygoideus Internus 207 Parotid Gland ib. vect. II. Of the Vessels and Nerves 208 External Maxillary Artery ib. XVH Page Chap. IX. External Carotid Artery and Ramifica- tions 209 Frontal Artery 210 Veins 211 Portio Dura of the Seventh Pair, or Facial Nerve ib. Superior Cervical Nerve ib. Superior Maxillary Nerve 212 Inferior Maxillary Nerve ib. Frontal Nerve 213 Chap. X. Dissection of the Throat 214 Sect. I. Muscles situated about the Entry of the Fauces 215 Constrictor Isthmi Faucium ib. Palato-pharyngeus ib. Circumflexus, seu Tensor Palati 216 Levator Palati 217 Azygos LTvul» 10> Sect. II. Muscles situated on the Pos- terior Part of the Pharynx 218 Constrictor Pharyngis Inferior ib- Constrictor Pharyngis Medius ib. Constrictor Pharyngis Superior 219 Sect. III. Muscles of the Larynx 220 Crico-arytjenoideus Posticus ib. Crico-artyjenoideus Lateralis 221 Thyreo-arytsenoideus ib. Arytjenoideus Obliquus ib. Arytienoideus Transversus 222 Thyreo-epiglottideus i°- Arytjeno-epiglottideus ib- Chap. XL Dissection of the Orbit of the Eye. Sect. I. Muscles situated within the Orbit 223 b 2 XV111 Chap. XL Sect. II. Chap. XI. Page Levator Palpebrse Superioris 224 Levator Oculi ib. Depressor Oculi ib. Adductor Oculi 225 Abductor Oculi ib. Obliquus Superior, seu Trochlearis ib. Obliquus Inferior 226 Lacrymal Gland, Puncta and Sac ,--- Caruncula Lacrymalis 226, , 227 Of the Vessels and Nerves MET with in the Dissection of THE Orbit 227 Ophthalmic Artery ib. Infra-orbitary Artery 228 Veins ib. Optic Nerve ib. Nerve of the Third Pair, and its R ami- fications ib. Nerve of the Fourth Pair 229 First Branch of the Fifth Pair ib. Infra-orbitary Nerve 230 Sixth Pair ib. Dissection of the Muscles situ- ated on the Posterior Part of the Trunk and Neck. Trapezius, seu Cucullaris 231 Latissimus Dorsi 232 Rhomboideus 233 Levator Scapula 234 Serratus Magnus ib. Serratus Superior Posticus 235 Splenius 236 Serratus Posticus Inferior 237 Sacro-lumbalis 238 Longissimus Dorsi 238 XIX Page Chap. XII. Spinalis Dorsi 239 Cervicalis Descendens 240 Transversalis Colli ib. Trachelo mastoideus 241 Com plexus ib. Semi-spinalis Colli 242 Semi-spinalis Dorsi 243 Rectus Capitis Posticus Major ib. Rectus Capitis Posticus Minor 244 Obliquus Capitis Superior ib. Obliquus Capitis Inferior 245 Multifidus Spinx ib. Interspinales Colli, Dorsi, et Lumborum 246 Intertransversales Colli, Dorsi, et Lum- borum 1D- Chap. XIII. Dissection of the Muscles situ- ated between the Ribs, and on the Inner Surface of the Sternum. Intercostales Externi, and Levatores Costarum 247 Intercostales Interni 248 Triangularis Sterni 249 Chap. XIV. Dissection of the Muscles situ- ated on the Anterior Part of the Neck, close to the Vertebra. Longus Colli 250 Rectus Capitis Internus Major ib. Rectus Capitis Internus Minor 251 Rectus Capitis Lateralis ib. Chap. XV. Dissection of the Superior Ex- tremity. Sect. I. Or the Dissection of the Shoul- der and Arm 252 x»x Page Chap. XV. Cutaneous Veins and Nerves 252, 253, 254 Muscles situated on the Shoulder and Sect. II. Arm 254 Deltoides ib. Supra-spinatus 256 Infra-spinatus 257 Teres Minor ib. Teres Major 258 Subscapularis 259 Biceps Flexor Cubiti ib. Coraco-brachialis 261 Brachialis Internus 262 Triceps Extensor Cubiti 263 Dissection of the Fascia AND Muscles situated on the Cu- bit or Fore-arm 264 Fascia 265 Situation of the Vessels at the Bend of the Arm ib. Muscle's situated on the Fore-part of the Cubit, and arising from the Inner Condyle of the Os Humeri 265 1. Superficial:— Pronator Radii Teres ib. Plexor Carpi Radialis 267 Palmaris Longus 268 Flexor Carpi Ulnaris 269 Flexor Sublimis Perforatus ib. 2. Deep-seated:— Flexor Profundus Perforans 271 Flexor Longus Pollicis ib. Pronator Quadratus 272 Muscles situated on the outer and back- part of the Fore-Arm, and arising from the outer Condyle of the Os Hu- meri 273 XXI Page Chap. XV. Sect. III. 1. Superficial:— Supinator Radii Longus 273 Extensor Carpi Radialis Longior 274 Extensor Carpi Radialis Brevior 275 Extensor Digitorum Communis 276 Extensor Carpi Ulnaris 277 Anconeus ib. 2. Deep-seated:—■ Supinator Radii Brevis 278 Extensor Ossis Metacarpi Pollicis Manus 279 Extensor Primi Internodii Pollicis Manus ib. Extensor Secundi Internodii Pollicis Manus 280 Indicator ib. Dissection of the Palm of the Hand 282 Fascia Pal maris 283 Palmaris Brevis ib. Flexor Tendons ib. Lumbricales ib. Short Muscles of the Thumb and Fore-finger ib. Abductor Pollicis Manus ib. Flexor Ossis Metacarpi Pollicis 285 Flexor Brevis Pollicis Manus ib. Adductor Pollicis Manus 286 Abductor Indicis ib. Short Muscles of the Little Finger 287 Abductor Minimi Digiti Manps ib. Flexor Parvus Minimi Digiti Manus 288 Abductor Metacarpi Minimi Digiti Manus ib. Interossei Interni 289 XX11 Page Chap. XV. Interossei Externi 289 Sect. IV. Of the Vessels and Nerves of the Superior Extremity 290 Brachial Artery and its Ramifications ib. Venae Comites 291 Nerves of the Axillary Plexus 297 APPENDIX. The Ruyschian Art and Method of making Preparations to exhibit the Strvcture oj the Human Body. The Injecting Tray and its Appendages 302 Explanation of the Plate 303 Preparations of*the Viscera 304 General Observations ib. Preparations of Morbid Parts ib. Preparations made by Macerating; 305 General Observations ib. Bones ib. A Foetus ib. Cuticle 306 Injecting Instruments ib. Injections ib. Coarse Injections ib. Fine Injections ,307 Minute Injections _ ib. General Observations 308 Preparation made with Coarse Injection ib. General Observations 309 Blood-vessel Subject ib. A Head, for Arteries and Veins 318 XXI11 Page An Arm, for Arteries and Veins 311 A Lower Extremity, for Arteries and Veins 312 The Gravid Uterus, for Arteries and Veins ib. A Placenta, for Arteries and Veins 312 The Heart, in Situ ; with the Head and Adjacent Vessels ib. A Foetus, to exhibit the Peculiarities of its C irculation 314 Penis 315 Testicle 316 The System of the Vena Portae ib. Heart 317 Stomach. Intestines. Bladder ib. General Observations ib. Preparations with Minute Injection 318 Bones ib. A Foetus ib. Uterus 319 An Adult Head 320 Preparations with Quicksilver ib. General Observations 321 A Superior Extremity ib. An Inferior Extremity ib. A Parotid Gland ib. Liver 322 Lungs ib. Hand ib. Lacteals 323 Corroded Preparations ib. General Observations ib. Heart and Lungs 324 Heart ib. Liver ib. Kidney 325 COMPENDIUM OF PRACTICAL ANATOMY. GENERAL RULES FOR DISSECTION. DEXTERITY in the manual operation of dissection can only be acquired by practice ; the observance, how- ever, of certain general rules will facilitate the labour of the student. 1. The position of the hand in dissecting should be the same as in writing or drawing; and the knife, held, like the pen or pencil, by the thumb and the two first fingers, should be moved by means of them only; while the hand rests firmly on the two other fingers bent inwards as in writing, and on the wrist. The in- strument can be guided with much more steadiness and precision.in this way, than when it is moved by means of the wrist, elbow, or shoulder, in the manner which young dissectors often fall into. 2. No more of the integuments should at any time be removed, than is necessary for the present dissec- tion, as exposure to the air renders the parts dry and indistinct. 3. In dissecting muscular parts, the muscles should be extended ; the cellular membrane which connects them to the integuments should be placed on the stretch, and entirely removed with the skin; the knife should be kept close to the muscles, and carried steadily in the direction of their fibres, separating a fasciculus at each stroke:—thus the exposed surface will appear clean, and the course of the fibres dis- tinct. 4. When small vessels are to be demonstrated, an- other method is to be followed ; the skin only must be removed, and the cellular membrane cautiously and slowly dissected from the vessels. 5. During dissection, every little operation should be practised, which can give the dexterity of hand so essential to the surgeon: such are, the use of the catheter and probang, the introduction of a probe through the nose into the Eustachian tube, or nasal duct, and the cutting down to the various arteries which may become the object of surgical operations: as the external iliac, femoral, anterior and posterior tibial, brachial, radial, and ulnar, &c. The grand object of the surgical student is to ac- quire a knowledge of the relative situation of parts. This should be kept in view in all his anatomical labours. Hence, when he is dissecting the muscles, he should carefully expose the chief blood-vessels and nerves, and attentively consider their position with regard to each other, and to the surrounding parts. This species of knowledge will afford him the most essential assistance in his future operations on the living subject; in which, indeed, it is so necessary, 3 that we are perfectly astonished to see persons rash enough to use the knife without possessing this in- formation; but we view the hesitation, confusion, and blunders by which such operators betray their igno- rance to the bystander, as the natural result, and the well-merited but too light punishment, of such criminal temerity. The smaller arteries and veins, and the minute nervous ramifications, will be more advantage- ously studied in subjects devoted to those purposes, and prepared by means of injection, immersion in spirits of wine, &c. The reader will observe, that, in general, the mus- cles of one side of the body only are described, because all the muscles of the body have correspondent ones on the opposite side, with a few exceptions, which are pointed out. To the description of each muscle are subjoined the synonyma of the best myological writers, and the names* proposed by professor Dumas, of Montpellier, in his new nomenclature. * These names will be distinguished by being placed last among the synonyma of each muscle; their terminations, as adapted to the French language, are retained. The following is the list of the changes made in the names of the bones, on which the new nomenclature of Dumas is founded. Sus-Acromion is the name given to the edge of the cla- vicle placed above the acromion of the scapula. Sous-Acrotnion to the edge of the same bone situated under- neath. Scapulum to the scapula. Trochiter to the greater protuberance near the head of the os humeri. 4 The Bursa: Mucosas met with in the dissection of the muscles are not regularly enumerated; but it is to be understood, that wherever tendons are described as rubbing on bones, muscles, or other tendons, a sac is formed by the surrounding cellular membrane, se- creting synovia, to lubricate the parts in motion. Trochanter to the great trochanter of the os femoris. Trochin to the lesser protuberance near the head of the os~humeri. Trochantin to the lesser trochanter of the os femoris. JEpitrochle'e to the internal condyle of the os humeri. Epicondyle to the external condyle of the os humeri. Phalange to the first phalanx of the fingers or toes. Phalangine to the second phalanx. Phalangette to the third phalanx. Sus, above—sous, below—pre", before. These synonyma, however, are rather to be considered as a matter of curiosity, than as names which have any chance of com- ing into general use. Being intended to convey a sort of ana- tomical description of the muscles, a great proportion of them are by far too long for names. The disadvantages of that nomencla- ture are pointed out by Dr. Barclay, of Edinburgh, in a late work on the subject, a work which discovers abilities of the first order. From the specimens which this anatomist has already given, it is to be expected, that he will soon present the world with a com- plete list of names, much better adapted to general use than any that have hitherto been employed. New terms, however, ought first to be given in the Latin language. They would thus be more easily adopted by anatomists of all countries, and might af- terwards, if necessary, be translated into the various modern lan- guages, in such a manner as would best suit the genius of each. j CHAP I. DISSECTION OF THE ABDOMEN. IN dissecting a subject, it is usual to begin with the Muscles of the Abdomen. SECT I. muscles of the abdomen, and the parts con- nected with them in dissection. THESE muscles are ten in number, five on each side. An incision should be made through the integu- ments, from the sternum to the os pubis; and this should be crossed by another passing immediately be- low the umbilicus: dissect off the flaps; this will lay bare, 1. The Obliquus Descendens Externus.__ Origin: By eight triangular fleshy slips, from the lower edges and external surfaces of the eight inferior ribs, at a little distance from their cartilages; the five superior slips meet on the ribs an equal number of the digitations of the serratus major anticus, and the three inferior are connected with the attachments which the latissimus dorsi has to the ribs. Often there are only seven portions. To gain a complete a 2 6 view of this muscle, the neighbouring portions of the pectoralis major, serratus anticus, and latissimus dorsi should be dissected with it. The muscular fibres proceed obliquely downwards and forwards, and about the middle of the side of the belly terminate abruptly in a thin broad tendon, which is continued in the same direction over all the fore- part of the belly. Here it covers the anterior surface of the rectus abdominis; it is very thin at the upper part, where the rectus lies on the cartilages of the ribs, and is often removed by the beginner, unless he is very cautious. Insertion: Tendinous and fleshy, into two anterior thirds of the outer edge of the spine of the os ilium; tendinous, into the whole length of Poupart's liga- ment, into the os pubis, into the ensiform cartilage, and into the whole length of the linea alba. Situation: It is quite superficial, and covers the whole of the anterior part of the abdomen. The muscular part is closely covered by a thin expansion of cellular substance, which might be mistaken for tendinous fibres, but it is only the cellular membrane condensed, and ought to be removed along with the in- teguments. Use : To draw down the ribs in expiration, to bend the trunk forwards when both muscles act, or to bend it obliquely to one side when one of them acts singly; to raise the pelvis obliquely when the ribs are fixed; to compress the abdominal viscera, to thrust the dia- phragm upwards, to assist in the expulsion of the urine and fxces, and of the foetus. Synonyma: Obliquus externus abdominis;—obli- 7 quus descendens;—obliquus major;—-ilio pubi-costo- abdominal. In the course of the dissection of this single muscle) the following points must be attended to. The Linea Alba, a white line running along the middle of the abdomen, from the cartilago ensiformis to the os pubis ; formed by the tendinous fibres of the two obliqui and the transversalis muscles, interlaced with those of the same muscles on the opposite side; it is half an inch broad at the navel; and decreases gra- dually botli above and below that part; but particularly in the latter situation, where it is reduced at last to a mere line. Linea Semilunaris, a semicircular white line, run- ning from the os pubis obliquely upwards over the side of the abdomen, at the distance of about four inches from the linea alba ; formed by the tendons of the two oblique and transverse muscles uniting at the edge of the rectus, before they separate to form the sheath for that muscle. LiNEiB Transversa, three or four white lines, crossing from the linea semilunaris to the linea alba; formed by the tendinous intersections of the recti shining through the strong sheath which covers them : —These are not evident in all subjects in this stage of the dissection. Umbilicus, or Navel. This whkh, before the in- teguments were removed, was a depression, appears now a prominence; it consists of condensed cellular membrane:—In the foetus, it was a foramen which gave passage to the two umbilical arteries, the umbili- cal vein, and the urachus. 8 Annulus Abdominalis, or Ring, an oblique slit or opening just above the angle of the pubis; formed by the tendon of the external oblique, divided into two portions called the pillars or columns of the ring, one of which (the superior or internal) is attached to the symphysis, and the other (the inferior or external) to the angle of the pubis ; and allowing a passage to the spermatic cord in the male, and the ligamentum teres of the uterus in the female. This slit is very impro- perly named a ring, since its figure is triangular ; the pubis is the base, the two columns are the two sides of the triangle. The apex has indeed a rounded figure in consequence of some transverse fibres, which con- nect the two columns where they first separate ; and it points obliquely upwards and outwards. It belongs to the external oblique alone, there being no such opening, either in the internal oblique, or the transver- salis; it is much smaller in the female than in the male. Ligamentum Inguinale, seu Poupartii, seu Pal- lopii, a strong ligament, stretching from the anterior superior spinous process of the os ilium, to be fixed to the spine of the os pubis. This in truth is merely the lower edge of the tendon of the obliquus externus abdominis, extended from the anterior superior spi- nous process of the ilium to the angle of the pubis, although, in compliance with received notions, I have described it as a separate ligament. It covers the femoral vessels and nerves, and certain muscles, and has lately been often described under the name of the Crural Arch. It is also the same part as the posterior column of the abdominal ring. The stu- 9 dent will be much confused by this multitude of names, unless he remembers that they denote only one object; that the crural arch, the inferior or outer column of the abdominal ring, Poupart's or the inguinal ligament, are so many names applied to the inferior border of the tendon of the external oblique muscle of the abdomen. I would advise the student, before he proceeds to the dissection of the other abdominal muscles, to dis- sect the parts in the groin, and to examine the situa- tion of the great inguinal vessels. In taking off the skin from the groin, you will not find a strong regular fascia, as on the outer part of the thigh, but a confused and irregular aponeurosis coming off from the abdomen, and going down upon the thigh, strengthened by the intermixture of con- densed cellular substance, and very loose above the great vessels. Immediately under the skin, and above this apo- neurosis, you perceive a congeries of lymphatic glands, and sometimes the lymphatic vessels themselves can be distinguished by their semi-transparent coats, and knotted appearance. Also, immediately under the skin, you will find the Vena Saphena running from below upwards, at first lying on the fascia, and then gradually sinking through it to join the femoral vein, about an inch below Poupart's ligament. On removing this irregular fascia, we come down upon the great vessels, which lie deeply imbedded in cellular substance, and are closely invested and sup- ported by a firm sheath, or fascia, consisting chiefly of cellular substance, very much condensed. This 10 should all be cautiously removed with the scissars, along with some lymphatic glands which lie amongst the fat. Observe the order in which the parts are si- tuated under the crural arch:—that the great exter- nal iliac vein lies' next to the pubis;—that the exter- nal iliac artery is on the outside of this, in close con- tact with it;—that the anterior crural nerve is half an inch exterior to the artery, and lies on the iliacus internus;—and that the outer half of the space left under the crural arch is filled by the psoas magnus and iliacus internus muscles. Observe how the cru- ral arch is stretched over the parts just enumerated; -—how it forms a thin, but firm, sharp, and crescent- shaped edge towards the pubis (constituting the seat of stricture in the femoral hernia, and sometimes called Gimbernat'a ligament);—how the artery is placed in relation to the angle of the pubis and spine of the ilium ;—how it passes under the middle of the arch, and, before it has fairly emerged into the thigh, sends off two considerable branches. (1.) A. Circumflex a Ilii is sent off from the outside, passes upwards and outwards, runs along the inside of Poupart's ligament, till it arrives at the an- terior superior spinous process of the os ilium ; thence it is continued along the inside of the spine of the ilium, lying close upon the bone between the trans- versalis abdominis and the upper edge of the iliacus internus, to both of which it gives twigs, and ends in inosculating with the ileo-lumbar artery. That distribution, however, cannot be seen in this stage of the dissection. (2.) A. Epigastrica comes off from the inside of 11 the artery, crosses the external iliac vein, passes ob- liquely upwards and inwards, under Poupart's liga- ment, to which it is but loosely connected, and runs behind the upper extremity of the abdominal ring and spermatic cord, to reach the rectus abdominis. At first it is situated between the posterior surface of that muscle and the peritoneum, but higher up between the muscular fibres and the sheath. It terminates in ramifications, which supply the rectus, and which in- osculate with the ramifications of the mammaria in- terna, sent down from the thorax on each side of the sternum. The dissection of the other abdominal muscles may now be continued. Dissect off the serrated origin of the external ob- lique from the ribs, and from the spine of the os ilium, and detach it from the obliquus internus, which lies below it, and which is connected to it by loose cellu- lar substance, and by small vessels. Continue to se- parate the two muscles, till you find their tendons firmly attached, i. e. a little way beyond the linea se- milunaris. Separate the tendon from the crural arch to within half an inch of the abdominal ring. 2. Obliquus Ascendens Internus.—Arises by short tendinous fibres, which soon become fleshy, from the whole length of the spine of the os ilium, and from the fascia lumborum*; also fleshy from the * Some describe it as arising from the sacrum and three in. ferior lumbar vertebra ; but this is not accurate. It arises from a tendinous fascia common to it and to certain muscles of the back, as the serratus posticus inferior; this may with propriety be named Fascia Lumborum. 12 upper part of Poupart's ligament at the part next to the os ilium. The fibres run in a radiated direction ; those which originate from the back-part of the os ilium, run ob- liquely upwards; those from the fore-part of the ilium pass more transversely across the belly; and from Poupart's ligament the fibres descend. The fleshy belly is continued rather more forward than that of the external oblique, before it terminates in a flat tendon. Inserted into the cartilages of the six or seven lower ribs,—fleshy into the three inferior, and, by a tendinous expansion, which is extremely thin, resem- bling cellular membrane, into the four superior, and also into the ensiform cartilage. The sheet of tendon tn Which the^ fl€s"liy belly ends, is continued, single and undivided, into the linea semilunaris, where, ad- hering pretty firmly to the tendons of the obliquus externus and transversalis, it divides into two layers. The anterior and more considerable layer joins the tendon of the external oblique, and runs over the rfcctus, to be inserted into the whole length of the linea alba: the posterior and thinner layer, adhering to the anterior surface of the transversalis, passes into the linea alba behind the rectus, as low as half-way between the umbilicus and os pubis ; but below this place the whole tendon of the internal oblique passes along with that of the external oblique before the rec- tus, and is inserted into the lower part of the linea alba. The inferior edge of the muscle extends in a nearly straight direction over the spermatic chord to 13 be fixed by a tendinous attachment to the angle of the pubis. Situation: It is covered by the obliquus descendens externus and latissimus dorsi. Use : To assist the obliquus externus ; but it bends the trunk in the reverse direction, so that the muscle on each side co-operates with the obliquus externus of the opposite side. Synonyma: Obliquus internus abdominis ;---obli- quus ascendens ;—obliquus minor ;—ilio-lumbo-costi- abdominal. About the middle of Poupart's ligament, a delicate fasciculus of fibres is sent off from this muscle over the spermatic cord, where it passes under its edge in its way to the ring. This is named the Cremasteu, and is continued down on the cord, till it is insensibly lost on the tunica vaginalis testis; it will be seen in the dissection of the scrotum : Its use is to suspend, draw up, and compress the testicle. We must now dissect the attachments of the inter- rial oblique from the cartilages of the ribs, from the fascia lumborum, and from the spine of the os ilium, and, by continuing our dissection from behind for- wards, separate it from the transversalis abdominis, which lies under it. This separation may be conti- nued as far as where the tendons of the two muscles are inseparable, i. e. rather more forward than the linea semilunaris. As this muscle lies very close upon the transversalis, caution is required to avoid detaching both muscles together. Let the student begin his separation at the crista of the ilium, where the course of the circumflexa ilii artery and vein will show B 14 him when he has arrived at the surface of the transver- salis. 3. Transversalis Abdominis.---Arises, tendi- nous, from the*fascia lumborum, and back part of the spine of the os ilium ; fleshy from all the remaining part of the spine of the ilium, and from the inner sur- face of Poupart's ligament; and fleshy from the inner or back part of the cartilages of the seven lower ribs, where its fibres meet those of the diaphragm. The fleshy fibres proceed transversely, and end in a flat sheet of tendon, which, after being connected to the other tendons at the linea semilunaris, passes with the posterior layer of the internal oblique behind the rectus, and is inserted into the ensiform cartilage, and into the whole length of the linea alba, excepting its lowermost part; for, at the middle distance be- tween the umbilicus and os pubis, a slit or fissure is formed in this tendon, through which the rectus abdo- minis passes ; and the remainder of the tendon passes before the rectus, to be inserted into the lower part of the linea alba. Its inferior edge is connected with that of the preceding muscle in its insertion into the pubis. Situation: It is covered by the obliquus descendens internus, and is lined by the peritoneum. Use : To support and compress the viscera of the abdomen. Synonyma: Transversus abdominis ;—lumbo-ili-ab- dominal. Where the transversalis is detached from its origins, and turned back towards the linea semilunaris, the peritoneum is laid bare, except in the neighbourhood 15 of the crural arch, where it is covered by a thin fascia arising from Poupart's ligament, and continued up- wards between the peritoneum and transversalis mus- cle, until it is gradually lost. This is named by Mr. Cooper, its discoverer, the fascia transversalis, and prevents the bowels from being protruded under the inferior margins of the obliquus internus and trans- versalis muscles. It is perforated about the middle between the ilium and pubes, by an opening for the passage of the spermatic chord, which then goes obliquely downwards inwards and forwards to the ring of the external oblique. Thus the abdominal ring is a canal, having an upper or internal opening, formed in the fascia transversalis, and a lower or exter- nal one in the tendon of the obliquus externus*. The sheath of the rectus is now to be attended to ; it is formed by the tendons of the three other mus- cles, viz. the two obliqui, and the transversalis: These, when they reach the edge of the rectus, form the appearance named Linea Semilunaris; they then split and inclose the rectus in their duplicature ; the whole tendon of the external oblique, with the ante- rior layer of the internal oblique, passes before the rectus ; and the whole posterior layer of the internal oblique, together with the whole tendon of the trans- versalis muscle, passes behind the rtctus, excepting at the lower part; but, for two or three inches above the pubis, all the tendons go in front of the muscle, • For more complete descriptions of these very important parts, see Mr. Cooper's Works on Hernia, or Mr. Lawrence's Treatise on the same subject. 16 ;:nd the posterior part of the sheath is consequently deficient, the rectus lying naked on the peritoneum. The two oblique muscles are now to be replaced ; then, making an incision by the side of the linea alba, and thus opening the sheath of the rectus through its whole length, you dissect it back towards the linea se- milunaris, and thus lay bare the fibres of the muscle next to be described. 4. Rectus Abdominis.—-Irises, by a flat tendon, from the fore-part of the os pubis; as it ascends, its fleshy belly becomes broader and thinner. Inserted, by a thin fleshy expansion, into the ensi- form cartilage, and into the cartilages of the three in- ferior true ribs. Situation : This pair of muscles is situated on each side of the linea alba, under the tendons of the ob- lique muscles. The muscle is generally divided by three tendinous intersections; the first is at the umbi- licus, the second where it runs over the cartilage of the seventh rib, and the third in the middle between these; and there is commonly a half intersection be- Low the umbilicus. By these intersections the mus- cle is connected firmly to the anterior part of its sheath, forming the line^e transversa ; while it adheres very slightly by loose cellular substance to the posterior layer. Use : To compress the fore-part of the abdomen, to bend the trunk forwards, or to raise the pelvis. Synonyma: Pubio-sternal. On each side of the linea alba, and inclosed in the lower part of the sheath of the rectus, is sometimes found a small muscle, named 17 5. Pyramidalis.—Origin: Tendinous and fleshy, of the breadth of an inch from the os pubis, anterior to the origin of the rectus. Insertion: By an acute termination, near half-way between the os pubis and umbilicus, into the linea al- ba and inner edge of the rectus muscle. Situation: It lies betwixt the lower portion of the two recti muscles. Use: To assist the lower part of the rectus. Synonyma: Pyramidalis, vel succenturiatus, pubio- umbilical. SECT. II. dissection of the cavity of the abdomen. THE abdomen is divided into three regions, each of which is again subdivided. 1. The Epigastric, or upper region, includes the part covered at the side by the ribs; its lateral por- tions are named the right and left Hypochondria, and the depression in its middle the scrobiculus cordis. 2. The Umbilical, or middle region, is the space immediately under the former; and it extends below to the anterior superior spines of the ilia. Its sides are called the lumbar or iliac regions. 3. The Hypogastric, or lowest region, is sub- divided into three parts, one middle, termed Re- b 2 18 gio Pubis, and two lateral, named Inguinal re- gions. Make a longitudinal incision from the scrobiculus cordis to the umbilicus, and from that point an ob- lique incision on each side towards the anterior spi- nous process of the os ilium, forming thus three tri- angular flaps. In doing this, avoid cutting the in- testines, by raising the muscles from them after the first puncture. Before you disturb the viscera, observe the general situation of those parts which appear on first opening the abdomen. 1. The internal surface of the Peritoneum, smooth, shining, and colourless, covering the parietes of the abdomen, and the surface of all the viscera. 2. In the triangular portion of integument folded down over the pubes, three ligamentous cords project through the peritoneum, two running laterally, and the other in the middle, towards the navel. These are the remains of the two umbilical arteries and the urachus. 3. The epigastric artery, accompanied by two veins, may be seen through the peritoneum, ascend- ing obliquely upwards and inwards from under Pou- part's ligament. 4. The upper edge of the liver is seen extending from the right hypochondriac region, across the epi- gastric, into the left hypochondriac region ; in it a fis- sure is seen, into which enters, inclosed in a duplica- ture of peritoneum, the ligamentum teres, which was, in the fetus, the umbilical vein. The fundus of the 19 gall-bladder, if distended, is sometimes seen project- ing from under the edge of the live. 5. The Stomach will be found lying in the left hypochondriac region, and upper part of the epigas- tric ; but, if distended, it protrudes into the umbilical region. 6. The Great Omentum proceeds from the great curvature of the stomach, and stretches down like a flap over the intestines. 7. The Great Transverse Arch of the Co- lon will be seen projecting through the omentum; it mounts up from the os ilium of the right side, crosses the belly under the edge of the liver, and un- der the greater curvature of the stomach, and de- scending again upon the left side, sinks under the small intestines, and rests upon the wing of the left or ilium. 8. The Small Intestines lie convoluted in the lower part of the belly, surrounded by the arch of the colon. Such is the general appearance on first opening the abdomen; but this will vary somewhat, as one intes- tine may happen to be more inflated than another, or as the position of the body may have been after death. It will now be proper to consider the parts more minutely : 1. The Peritoneum.—Observe how it is reflected from the parietes of the abdomen overall the viscera, so that they may be said to be situated behind it; trace its reflections from side to side, and from above downwards; you will see that the external coat of 20 every viscus, and all the connecting ligaments, are re- flections or continuations of this membrane. (l.) The four Ligaments of the Liver are form- ed by the peritoneum, continued from the diaphragm and parietes of the abdomen. a, The Middle or Suspensory Ligament, in- closing in its duplicate the Ligamentum Teres. b, The Coronary Ligament, connecting the upper surface of the liver to the diaphragm. c, The Broad Ligament of the right side. d, The Broad Ligament of the left side. (2.) The Lesser Omentum, or Epiploon, or the Mesogastrion, is formed by two lamina? of perito- neum, passing from the under surface of the liver to the lesser curvature of the stomach, and containing in its duplicate the vessels of the liver. (3.) The Great Epiploon or Omentum.__ Observe, that the peritoneum, coming from both sur- faces of the stomach, and from the spleen, proceeds downwards into the abdomen, and is then reflected back upon itself, till it reaches the transverse arch of the colon, where its lamina? separate to invest that intestine. This Reflection is named the Great Omen- tum ; it is a pouch or bag, composed of four lamina? of peritoneum, and the opening into it is by the Fo- ramen of Winslow: Observe the situation of this semilunar opening; it is on the right side of the ab- domen, at the root of the lesser lobe, or lobulus spi- gelii of the liver; it leads under the little epiploon, under the posterior surface of the stomach, but above the pancreas and colon, into the sac of the omentum; „—the omentum sometimes reaches to the lower part 21 of the hypogastric region, sometimes not beyond the V navel; it contains in its duplicature more or less of adipose substance. (4.) The Mesentery.—Observe, that the perito- neum, reflected from each side of the vertebra:, pro- ceeds forward, to connect the intestines loosely to the spine; that it begins opposite to the first lumbar ver- tebra, crosses obliquely from left to right, and ends half-way between the last lumbar vertebra and the groin. At its commencement, it binds down the ex- tremity of the duodenum, and it terminates where the head of the colon begins. The great circum- ference which is in contact with the intestines, is very much plaited or folded, and is several yards in length. Between the4amina? of mesentery, observe the Con- globate Glands, less numerous in old age: the branches of the superior mesenteric artery ramifying and forming arches; the mesenteric veins accompa- nying the arteries ; the trunk of the lacteals, situated contiguous to the mesenteric artery on its left side. It may sometimes be inflated by the blow-pipe. Nerves also run in the mesentery, but are not easily demonstrated. (5.) The Mesocolon is similar to the mesentery, and connects, in like manner, the colon to the spine. 2. Hepar, the Liver.—Situation: Partly in the right hypochondrium, which it fills up, reaching as low as the kidney of that side, partly in the epigas- trium, and running also some way into the left hypo- chondrium. Connected by its four ligaments to the inferior sur- face of the diaphragm, and by the lesser epiploon to 22 the small curvature of the stomach :—The little epi- ploon should now be removed, to discover the different parts of the liver. Observe the superior or convex surface adapted to the arch of the diaphragm ; the inferior or concave surface resting on the stomach ;—the posterior or thick edge lying against the vertebrx, and the anterior thin margin corresponding to the lower edge of the chest;---Observe the three lobes of the liver;—the great or right lobe ;—the small or left lobe;—the lobu- lus spigelii;—the great fissure, separating the right and left lobe, and receiving the suspensory ligament, and the ligamentum teres ;—the cavity of the porta? between the great lobe and lobulus spigelii;—the fis- sure on the right side of the lobulus for the vena cava inferior, which fissure is almost a complete foramen ; —the notch in the back-part for the vertebra?;—the depression in the right lobe for the gall-bladder. Ob- serve the vessels in the cavity of the porta?, the hepatic artery on the left side, the ductus communis choledo- chus on the right side, and betwixt, but at the same time behind them, the vena porta?; they are all sur- rounded by a plexus of nerves. These vessels and nerves pass along the edge of the mesogaster, or little omentum, surrounded and connected by adipose and cellular substance; the part is called Capsula Glis- soni. Observe that the ligamentum teres was the umbilical vein of the foetus, entering the vena porta?, and that the ductus venosus in the foetus (obliterated in the adult), leaving the vena porta?, passed into one of the vena? cava? hepatica?. 3. Vesicula Fellis, the Gall-Bladder.—- 23 Situation: In the right hypochondrium, in a superfi- cial depression on the under surface of the right sobe of the liver; it sends off the Ductus Cysticus, which, uniting with the Ductus Hepaticus, forms the Duc- tus Communis Choledochus ; this perforates the first curvature of the duodenum. • 4. Ventriculus, the Stomach.—Situation: In the left hypochondriac and epigastric regions: Con- nected to part of the inferior surface of the diaphragm, to the concave surface of the liver by the little epiploon, to the spleen by a reflection of peritoneum, and to the arch of the colon by the great omentum. Observe its greater curvature looking downwards, its lesser curva- ture looking upwards ; and its two lateral surfaces. In the living body, the greater curvature- is turned for- ward, and a little downward, the lesser arch backward, i. e. towards the spine, while one of the lateral convex sides is turned upwards, and the other downwards. Observe the bulging extremity on the left side, the cardia or upper orifice, where the oesophagus enters half-way between this great extremity and the lesser arch: the pylorus, or lower orifice, at the end of the small extremity, situated under the liver, and rather to the right side of the spine, feeling hard when touched. 5. The Intestines.—These form one continuous tube, but are divided into two portions, differing in their figure, structure, and functions, and distinguished by the names of small and large. The small intestine is divided into duodenum, jeju- num, and ileum; the large into cxcum, colon, and rec- tum. 24 (1.) Small Intestine;—about four times as large' as the body. a, The Duodenum is broader than any other part of the small intestine, but is short: it takes a turn from the pylorus upwards, and to the right side, passing un- der the liver and gall-bladder; then, turning upon itself, it descends, passing as low as the right kidney; it is in this space that it receives the pancreatic and gall ducts ; thence it crosses before the renal vessels, before the aorta, and upon the last vertebra of the back, firmly bound down by the peritoneum, which covers only its anterior surface; it then ascends from right to left, till it is lost under the root of the meso- colon. Turning back the colon and omentum, fixing them over the brim of the thorax, and pushing down the small intestines towards the pelvis, you find the duo- denum coming out from under the mesocolon, but still tied close to the spine; it terminates in the jejunum, exactly where the mesentery begins. The intestine in this course forms nearly a circle, the root of the meso- colon being the only part lying between its two extre- mities. You have now to trace the rest of the small intestine, which lies convoluted in the umbilical and hypogastric regions. b, Jejunum constitutes the first or upper half of the remaining small intestine, and is situated more in the upper part of the abdomen ; it is redder, and its coats feel thicker to the touch, from the greater number of the valvula? conniventes on its inner surface; its dia- meter exceeds that of the ilium. 25 t r, The lower half is named Ileum; it is situated more in the lower part of the abdomen, and terminates in the great intestine, by entering the caput coli, or be- ginning of the colon. As a general observation it may be said, that the con- volutions of the small intestine occupy the middle of the umbilical and hypogastric regions; but their situa- tion varies much, particularly according to the state of the bladder and rectum. The course of the tube, in- dependently of its convolutions, is from the left lumbar region, where the duodenum emerges_from under the mesocolon to the right inguinal region, where the ile- um terminates in the caput coli. (2.) Great intestine. \ d, The Cecum, or blind gut, is tied down by the peritoneum to the loins on the right side, lying in the space under the right kidney, hid by the convolutions of the ileum. On its posterTor part there is a little ap- pendage, of the shape of an earth-worm, named ap- pendix Cisci Vermiformis. e, The Colon.—Its commencement at the cxcum is termed Caput Coli, or head of the colon; it mounts upwards from the cecum over the anterior surface of the right kidney, to which it is connected by cellular substance, passes under the gall-bladder, which, after death, tinges it with bile ; and then, go- ing across the upper part of the belly, forms jts Great Transverse Arch. In its whole course it is con- tracted into cells by its muscular fibres, which are united together, forming longitudinal bands; and it has some fatty projections attached to its surface, named Appendices Epipioica?. Both these circum* c 26 stances distinguish the large from the small intestine, which the difference of size does not always. When the large intestine is empty, it contracts, and may be even smaller than the small; but if it were inflated, it could be distended to a much greater degree. The co- lon then goes backwards under the stomach and spleen into the left hypochondrium; and then, descending over the left kidney, it is again tied down; it after- wards turns over the brim of the pelvis, being at this part unconfined, and forming a loose and remarkable curvature, which is named the Sigmoid or Iliac Flex- ure. After this convolution, the intestine assumes the name of The Rectum.—Drawing aside the intestines, you find the gut continued over the anterior surface of the sacrum and os coccygis to the anus. On pulling the stomach towards the right side, you will perceive, 6. The Lien, or Spleen.—Situation: In the left hypochondriac region, between the great extremity of the stomach, and the neighbouring false ribs, under the edge of the diaphragm, and above the left kidney; to all of which it is connected by the peritoneum. It is of an oval figure; its external surface is gently convex; its internal surface irregularly concave, and divided by a longitudinal fissure, into which its vessels enter. 7. The Pancreas.—Situation: This gland was in part seen on removing the little epiploon; it is more fully exposed, by tearing through the great epiploon between the great curvature of the stomach, and the transverse arch of the colon. It lies in the cavity in- 27 to which the foramen of Winslovv leads; it extends from the fissure of the spleen across the spine, under the posterior surface of the stomach, and terminates within the circle formed by the duodenum; it is only covered on its anterior surface by the peritoneum. The Pancreatic Duct pierces the coats of the duodenum, and enters the cavity of that intestine, by an orifice common to it, and to the ductus communis choledochus. The duct runs along the very centre of the gland, where the whiteness of its coats will readily enable the student to distinguish.it. All the abdominal viscera may now be removed, ex- cept the rectum, where it descends into the pelvis, which, being tied, should be allowed to remain, for it belongs to the demonstration of those parts: or the liver and its vessels, with the pancreas, may be left, and the vessels entering the porta? of the liver traced. The peritoneum should now be carefully dissected from the diaphragm, and from the sides and back-part of the abdomen; thus the parts which lie more imme- diately behind that membrane may be examined. 8. Renes, the Kidneys.—Two glandular bodies, si- tuated in the posterior part of the cavity of the abdo- men, on each side of the lumbar vertebra?, between the last false rib and the spine of the ileum, and imbedded in a quantity of adipose membrane. In each kidney you may observe a lesser arch or con- cavity turned obliquely forwards and inwards; a greater arch or convexity turned obliquely backwards and outwards ;—two lateral surfaces;—two extremities, the superior of which is nearer to that of the opposite kidney than the inferior. Observe the renal or emul- 28 gent artery entering the lesser arch, the vein and ureter passing out. Observe the course of the ureter; it passes behind the peritoneum over the psoas muscle in- ■ to the pelvis, and runs between the rectum and bladder, which last it enters. 9. The Capsular Renales.—Two glandular bo- dies, situated on the upper extremity of each kidney, of an irregular figure, crescent-like, or somewhat tri- angular. By the removal of the peritoneum, several muscles are exposed, situated at the superior and posterior parts of the abdomen. One single muscle is situated in the superior part of the abdomen, Diaphragma, the Diaphragm, or Midriff.__ This is a broad, thin, muscular septum between the thorax and abdomen, situated obliquely; it is concave below, and convex above, the middle of it on each side reaching as high within the thorax as the fourth rib. It is divided into two portions: 1. The superior or greater muscle of the diaphragm, forms the transverse partition between the chest and abdomen, Arising, by distinct fleshy fibres, 1. From the poste- rior surface of the ensiform cartilage; 2. From the cartilages of the seventh, and all the false ribs; 3. From the ligamentum arcuatum, which is a ligament extended, somewhat indistinctly, from the top of the twelfth rib to the lumbar vertebra?, forming an arch over the psoas and quadratus lumborum muscles. From these origins the fibres run, in different direc- 29 tions, like radii from the circumference to the centre of a circle, and are Inserted into a broad tendon {tendinous centre, or cordiform tendon), which is situated in the middle of the diaphragm, and in which, therefore, the fibres from the opposite sides are interlaced. 2. The inferior or lesser muscle, or appendix of the diaphragm, lies on the bodies of the vertebra;, and Arises, by four small tendinous feet, on each side, from the second, third, and fourth lumbar vertebra?; these tendons soon join, to form a strong pillar on each side, named the Crus of the Diaphragm. The crura run obliquely upwards and forwards, form two fleshy bellies, a fasciculus of each of which crossing over to the other, decussates with the opposite one, and thus forms the interval of the two crura into a su- perior and inferior opening. Inserted \n\.o the posterior part of the middle cordi- form tendon. Situation: The diaphragm is covered on its supe- rior surface by the pleura, and on its inferior by the peritoneum; it separates the thoracic from the abdo- minal viscera: It is perforated in its fleshy and tendi- nous parts by several blood-vessels, and other import- ant organs. (1.) The aorta passes between the tendinous part of the crura, lying close upon the spine; and the thoracic duct passes betwixt the aorta and the right crus. (2.) A little above, and to the left side of the aorta, the oesophagus, with the eighth pair of nerves attach- c2 30 ed to it, passes through an oval fissure foimed in the fleshy columns of the inferior muscle. These two parts are separated by the decussating fasciculi just described. (30 The vena cava perforates the tendon towards the right side by a triangular hole. (4.) The posterior intercostal nerve, and branches of the vena azygos, perforate some of the posterior fibres of the crura:—The splanchnic, or anterior intercos- tal nerve, also passes through an opening in the sub- stance of the crura. (5.) On each side of the sternum there is a small fissure, where the peritoneum and pleura are only se- parated by adipose membrane.) Use: The diaphragm is one of the chief agents in respiration; in contraction it enlarges the cavity of the thorax, and produces inspiration; in expiration it is relaxed, and pushed up by the pressure of the viscera, from the action of the muscles of the abdomen, so as to diminish the cavity of the chest: it also acts in coughing, laughing, and speaking, and in the expul- sion of the urine and fa?ces. Synonyma: Septum transversum ;—septum mus- culare;—Thoraco abdominal. Winslow calls the middle aponeurosis the aponeurotic, plane of the dia- phragm ; by others it is called the centrum tendino- sum. Four pair of muscles are situated within the poste- rior part of the cavity of the abdomen. 1. The Psoas Parvus—It arises, fleshy, from the sides of the last dorsal, and first lumbar vertebra?; it 31 sends off a small long tendon, which, running on the inside of the psoas magnus, is Inserted, thin and flat, into the brim of the pelvis, at the junction of the os ilium and pubis. Situation: This muscle lies on the anterior part of the loins, betwixt the psoas magnus and the vertebra ; sometimes, however, it is wanting. - Use: To assist the psoas magnus in bending the loins forwards : in some positions, it will bend the pel- vis on the loins. Synonyma: Pre-lumbo pubien. 2. The Psoas Magnus.—It arises, fleshy, from the side of the body, and transverse process of the last ver- tebra of the back, and in the same manner from all those of the loins, by as many distinct slips. It runs down over the brim of the pelvis, and is Inserted, tendinous, into the trochanter minor of the os femoris, and fleshy, into that bone immediately be- low the trochanter. Situation: It is situated betwixt the psoas parvus and iliacus internus, close to the fore-part and sides of the lumbar vertebra?: at its origin it has some con- nection with the diaphragm, and with the quadratus lumborum. Use: To bend the thigh forwards, and roll it out- wards ; or, when the inferior extremity is fixed, to as- sist in bending the body. Synonyma: Lumbaris internus;—Pre-lumbo-tro- chantin. 3. The Iliacus Internus.—It arises, fleshy, from the transverse process of the last vertebra of the loins, from all the inner margin of the spine of the os ileum, 32 from the edge of that bone between its anterior supe- rior spinous process and the acetabulum, and from all its hollow part between the spine and the linea in- nominata. Its fibres descend under the outer half of Poupart's ligament, and join the tendon of the psoas magnus. Inserted with the psoas magnus. Situation: It fills up the internal concave surface of the os ileum, and is situated on the outside of the psoas magnus. It is covered by a pretty strong fascia, which is inserted into the crista of the ileum, and into the crural arch: Fascia Iliaca. The latter inser- tion prevents the bowels from descending under Pou- part's ligament, except at the inner edge of the iliac vein, which is accordingly the situation of the crural hernia, and which the student should examine most carefully. A part of this fascia is also continued be- hind the femoral vessels over the pubis, to form a part of the sheath which incloses those vessels*. Use: To assist in bending the thigh, and in bringing it directly forwards. Synonyma: Iliacho-trochantin. jY. B. The insertion of the two last-described mus- cles cannot be seen till the thigh is dissected, when it will be found to lie between the vastus internus and the pectina?us. 4. The Quadratus Lumborum__This muscle arises, tendinous and fleshy, from rather more than the posterior third part of the spine of the os ileum. * See the second part of Mr. Cooper's work on Hernia, and Mr. Lawrence's treatise quoted before. 33 Inserted into the transverse processes of all the ver- tebra of the loins, into the posterior half of the last rib, and, by a small tendon, into the side of the last vertebra of the back. Situation: It is situated laterally at the lower part of the spine, more outwardly than the psoas magnus, between the origin of the psoas and the transversalis abdominis. Use: To move the loins to one side, pull down the last rib, and* when both muscles act, to bend the loins forwards. Synonyma : Lumbaris externus ;—Ilio-lumbi-costal. OF THE VESSELS AND NERVES SITUATED BEHIND THE PERITONEUM. I. the arteries, viz. the aorta abdominalis, AND ITS BRANCHES*. THE Aorta passes from the thorax into the abdo- men, between the crura of the diaphragm, close upon the spine. It then descends on the fore-part of the vertebra, lying not exactly in the middle, but rather inclined to the left side. On the fourth lumbar ver- * In the description of the blood-vessels, the ramifications of the principal trunks are enumerated; but the student must remember that these can be seen only when injected, and when the subject is dissected for the express purpose of tracing the arteries. In an ordinary dissection, the trunks only can be de- monstrated. 34 tebra, it bifurcates into the two primitive or common iliac arteries. Branches of the Abdominal Aorta. 1. The two Phrenic Arteries arise from the Aorta, before it has fairly entered into the abdomen, and ra- mify over the diaphragm ;—sometimes they come off in one trunk, which bifurcates; sometimes one of them arises from the cceliac. 2. The CceLiAc Artery comes off at the point where the aorta has fairly extricated itself from the dia- phragm ; it is a single, large, but short trunk situated between the inferior surface of the liver, and the small curvature of the stomach, and surrounded by the meshes of the semilunar ganglion. It divides at once into three branches; and as they depart in different di- rections from one point, as from a centre, the trunk is called the Axis Arteri^e CoeLiAca:. (1.) A. Coronaria Ventriculi, the middle branch, is the smallest of the three ; it passes from the axis towards the left side, and arriving at .the cardiac orifice of the stomach, where it attaches itself to that organ, sends a branch round the cardia, named Ramus Coronaria Dexter. The trunk itself is then continu- ed along the lesser curvature from left to right, to inos^ culate with the pylorica or coronaria dextra: it sends off branches to the little epiploon, &c. It sometimes terminates in the liver, entering at the porta, and then it is the largest of the branches of the cceliac. In this case, the trunk, after ascending towards the left to reach the cardia, is reflected to the right, in 35 its way to the liver; and, at the point of reflection, gives off the coron. -ventric. (2.) Arteria Splenica, leaving the trunk of the cceliac, goes directly to the side, passes under the stomach, and along the upper border of the pancreas, running in a tortuous and serpentine course : it enters the left concave surface of the spleen in several branches, but, before doing so, it gives off the following branches: a, Pancreatice Parv;e to the pancreas, where it runs along the border of that viscus. b, Vasa Brevia to the bulging extremity of the stomach. c, A. Gastro-epiploica Sinistra, which runs along the greater curvature of the stomach, inosculat- ing with the gastro-epiploica dextra. (3.) Arteria Hepatica runs in a direction op- posite to the splenic, towards the right side; but not more than half of its blood goes to the liver: It sends off the following branches: a, Pylorica, or Coronaria Dextra, some- times comes off from the trunk of the hepatic, some- times from one of its branches:—reaching the pyloric end of the stomach, it sends its ramifications along the lesser curvature, to inosculate with the proper co- ronary artery. b, Gastro-epiploica Dextra, or Gastro- duodenalis, passes under the pylorus, to reach the great curvature of the stomach, along which it runs, inosculating with the gastro-epiploica sinistra, and sending branches upwards to the stomach, and down- wards to the omentum ; it also supplies the upper 36 part of the duodenum, and sends off a considerable branch to the right extremity of the pancreas. The hepatic artery then divides into the right and left hepatic. The Right is distributed to the right lobe of the liver, and to the gall-bladder. The Left supplies the whole of the left lobe, the lobulus Spigelii, and part of the right lobe of the »liver. 3. The Superior Mesenteric Artery is a single trunk; it leaves the aorta about half an inch lower than the coeliac artery,—it comes out from un- der the mesocolon, and stretches over the duodenum ; it enters the fold of peritoneum forming the mesen- tery, and runs down in this, gradually incurvating from the left to the right side. From the right side or concavity of this arch, three branches are given to the colon. (1.) A. Ileo-Colica runs down to the caput coli and last turns of the ileum ; its branches upon the small intestines inosculate with those branches of the superior mesenteric distributed to the small intestines in general; and on the great intestine, it inosculates with the next branch. (2.) A. Colic a Dextra.—This artery runs from the root of the superior mesenteric artery, across to- wards the right side of the colon, where that intes- tine begins to rise over the kidney. (3.) A. Colica Media—This branch goes di- rectly upwards from the trunk of the superior me- senteric, as it comes out from under the mesocolon. After running a little way upon the mesocolon, it divides; and the division going towards the right 37 side, makes a large inosculation with the colica dextra, while the left branch makes an opposite sweep, and joins the colica sinistra, which is a branch of the infe- rior mesenteric. Often there are only two branches instead of these three; viz. ileo-colica and colica dextra; then the c. media is a branch of the latter. Frequently too there is only one branch, called colica dextra, and dividing after its origin into the three above named. The left side or convexity of the arch of the superior mesenteric sends off from sixteen to twenty* branches, which, after forming frequent anastomoses and arches, proceed to the small intestines. 4. The Renal or Emulgent Arteries are two in number. Each artery arising, below the superior mesenteric, from the side of the aorta, passes to the kidney, and after having given twigs to the renal cap- sule and adipose membrane, enters the lesser arch of the kidney. The right artery is longer than the left, and passes behind the vena cava ascendens. 5. The Spermatic Arteries are also two; they come off about an inch below the emulgent from the fore-part of the aorta. Each artery descends behind the peritoneum, giving twigs to the parts in its course, and accompanied by the spermatic vein and nerves. It then passes through the abdominal ring, and enters the upper part of the testicle in five or six branches. In the female it supplies the ovaria and fundus uteri. 6. The Interior Mesenteric is a single trunk, which comes off rather from the left side of. the aorta, below the spermatic arteries; it passes in the mesentery D 38 to the left side of the abdomen, where it divides as fol- lows. (1.) The Colica Sinistra, an artery which ascends along the left side of the colon, to inosculate with the A. Colica Media. (2.) Branches which pass to the sigmoid flexure. (3.) The great trunk of the artery runs down behind the rectum, on which it ramifies largely, and is termed Art. Hemorrhoidalis Interna. 7. The Lumbar Arteries are five or six small ar- teries on each side, which arise from the back-part of the aorta, and are distributed to the spinal canal, perito- neum, muscles of the spine, and of the sides of the ab- domen and pelvis. They inosculate with the A. Epi- gastrica, Circumflexa ilii, Sec. 8. A. Sacra Media is a single artery, arises from the back-part of the aorta at its bifurcation, and de- scends along the anterior surface of the sacrum, giving twigs to all the neighbouring parts. At the fourth lumbar vertebra, the aorta bifurcates in- to the two primitive or common iliacs. The Iliaca Communis runs along the edge of the psoas muscle, and at an inch or two from its origin di- vides into, (1.) The Internal Iliac, which passes down into the pelvis. (2.) The External Iliac, which, following the direc- tion of the psoas muscle, passes under Poupart's liga- ment, and becomes the inguinal artery. 39 2. VEINS. The Vena Cava Abdominalis, vel Inferior, if formed by the junction of the two common iliac veins, it passes up through the abdomen on the lumbar verte- bra, and on the right side of the aorta. In this course it receives the following veins, which resemble their corresponding arteries. 1. The Lumbar Veins. 2. The Emulgent or Renal Veins;—the left is the longest, as it crosses over the fore-part of the aorta. 3. The Right Spermatic Vein ;—the left enters the left renal vein. The vena cava then passes through the fissure of the liver, being nearly surrounded by that viscus, and re- ceiving three branches from it, called the Ven£. Hepa- tic as. It then perforates the diaphragm, and enters the thorax. The common iliac vein of each side is formed by the union of two branches, the External and Internal Iliac Veins, which accompany the arteries of the same name :—The common iliac vein of each side lies on the inside of its artery ; hence both veins cross behind the right iliac artery, to unite and form the vena cava, on the fore-part of the lumbar vertebrx*. * It may be here proper to observe, that generally a great vein accompanies every great artery ; but when the ramifications be- come small, each artery is attended by two veins. 40 The Superior Me- senteric Vein-, the In- ferior Mesenteric udie artery will be more easily traced. 43 The muscles of the perineum consist of five pair, and a single muscle : Erector Penis, *"] Accelerator Urinje, i , C Sphincter I on each \ Transversus Perinei, S» . , < Ani, single Levator Ani, ( muscle. Coccygeus, J In commencing this important dissection, recollect that the erector muscle, covering the crus of the pe- nis, arises from the tuber ischii, and ascends on the inside of the ramus of that bone;—that the transversus perinei arises from nearly the same point, and crosses the perineum, lying often at a considerable depth in the adipose substance. The tuber ischii then becomes a proper place for the commencement of the dissec- tion ; carefully tracing the muscles arising from that point, remove all the cellular substance, situated in the perineum, while the muscular fibres are left un- touched; the Raphe or line running along the skin of the perineum, marks the place where the opposite muscles meet. The appearance of these muscles will vary in different subjects. In those who have died weak and emaciated, the fibres will be pale, and not very evident, while in strong muscular men, who have expired suddenly, they will be very distinct. This dis- section is to'be continued till all the parts between the tuberosities of the ischia on each side, and ~ be- tween the pubis before, and the tip of the os coccygis behind, are fairly brought into view. Observe The Erector Penis covering the crus of the pe- nis. The Accelerator Urin.e embracing the bulb 44 and lower part of the Corpus Spongiosum of the Urethra. The Sphincter Ani, encircling the anus. The Transversus Perinei, crossing the perine- um transversely. 1. The Erector Penis—Arises, tendinous and fleshy, from the tuberosity of the os ischium ; its fleshy fibres proceed upwards over the crus of the penis, adhering to the outer and inner edges of the ascending ramus of the os ischium, and of the de- scending ramus of the os pubis;—but before the two crura meet to form the body of the penis, it ends in a flat tendon, which is lost in the strong tendinous mem- brane that covers the corpus cavernosum. Situation: This muscle covers all the surface of the crus penis that is not in contact with bone; it arises on each side of the attachment of the crus to the bone. Use: It was formerly supposed to compress the crus penis, and thereby to propel the blood into the fore- part of the corpus cavernosum ; and to press the penis upwards against the pubis. But its obvious effect must be that of drawing the crus downwards to the tuber ischii; which cannot have any influence in con- tributing to the erect state of the organ. Synonyma: Ischio-cavernosus;—Ischio-caverneux. 2. The Accelerator Urin^e—Arises, by a thin' tendinous expansion, from the descending ramus of the pubis, and from the ascending ramus of the is- chium, nearly as far down as the tuber;—this origin lies under the crus of the penis, and the fleshy fibres are seen coming out from the angle between the crus 45 ;:iid the corpus spongiosum urethra; they proceed obliquely downwards and backwards, embrace the bulb and lower part of*the corpus spongiosum^ and are Inserted into a white tendinous line in the middle cf the bulb of the urethra, joining there with the muscle of the opposite side. The lowermost fibres run nearly transversely, while the superior fibres are very ob- lique. Use: To drive the urine and semen forwards, by compressing the lower part of the urethra, and to pro- pel the blood towards the corpus spongiosum and the glans penis. Synonyma: Ejaculator seminis;—Bulbo-cavernosus; Bulbo-syndesmo-caverneux. 3. The Transversus Perinei—Arises from the tough fatty membrane that covers the tuber ischii, im- mediately behind the attachment of the erector penis; thence its fibres run transversely inwards. Inserted into the central point of union where the sphincter ani touches the accelerator urina, and where a kind of tendinous projection is formed, common to the five muscles. Use: To dilate the bulb of the urethra, to prevent the anus from being too much protruded, and to retract it when protruded. Synonyma: Transversalis penis;—Transversalis urethrx;—Levator parvus, seu externus;—Ischio-pubi- prostatique. There is sometimes another slip of fibres, the Transversus Perinei Alter, which has the same 46 course, ami is inserted into the posterior part of the bulb of the urethra. 4. The Sphincter Ani consists of two semicir- cular planes, which run round the extremity of the rectum, passing nearly as far out as the tuber ischii; the fibres of each side decussate where they meet, and are Inserted into the extremity of the os coccygis be- hind*; and before, into a tendinous point common to this muscle, and to the acceleratores urina and trans- versi perinei. This tendinous point is worthy of re- mark ; it seems to consist in part of an elastic ligament- ous substance. Use : To close the anus, or extremity of the rectum, and to pull down the bulb of the urethra. It is in a state of constant contraction, independently of the will, in order to prevent the contents of the rectum from escaping except at those times when we make an ef- fort to evacuate them. Synonyma: Sphincter externus;—Sphincter cutane- us;—Coccygi-cutane-sphincter. More deeply seated than the muscles now described, we see some of the fibres of The Levator Ani.—This muscle arises from the inside of the os pubis, at the upper edge of the fora- men thyroideum, from the inside of the os ischium, from the tendinous membrane covering the obtu- * The sphincter ani often arises by an elastic tendon, approach. ing to the nature of a ligament, from the apex of the os coccygis. This tendon is of some length; it gives off muscular fibres, which surround the extremity of the rectum. 47 rator internus and coccygeus muscles;—from the se- micircular origin its fibres run down like radii towards a centre, and are Inserted into the two last bones of the os coccygis, and into the extremity of the rectum, passing within the fibres of the sphincter ani, but on the outside of the longitudinal fibres of the gut itself. Situation: This muscle, with its fellow, very much resembles a funnel, surrounding the extremity of the rectum, the neck of the bladder (which passes through a slit in its fibres), the prostate gland, and part of the vesicula seminales. Use: To draw the rectum upwards after the eva- cuation of the faces, to assist in shutting it, and to compress the vesicula seminales, and other viscera of the pelvis. Sy?ionyma: Musculus ani latus ;—Levator magnus, seu internus;—Pubio-coccigi-annulaire. 6. The Coccygeus arises, tendinous and fleshy, from the spinous process of the os ischium, and covers the inside of the posterior sacro-sciatic ligament; it forms a thin fleshy belly. Inserted into the extremity of the os sacrum, and into the lateral surface of the coccygis, immediately be- fore the gluteus maximus. Situation: Iris placed betwixt the levator ani, and edge of the gluteus maximus. Use: To support and move the os coccygis for- wards, and connect it more firmly with the sacrum. Synon. Ischio-coccigien. The accelerators urina? and transversi perinei must now be removed from their insertions. They may be 48 left suspended by their attachments to the bone. The rectum must be separated from the bladder, and pulled downwards. This dissection will expose a great part of the levator ani;—the neck and body of the bladder;—the prostate gland;—the vesicula semina- les ;—the glandula anteprostata ;—part of the vasa deferentia;—part of the ureters;—the urethra, its membranous part, its bulb, and corpus spongiosum ;— the crura penis, and their origins from the ischium;— Observe, 1. The connection of the bladder and rectum, and the cellular substance interposed between them. 2. The prostate gland: Situated between the blad- der and rectum, surrounding the beginning of the ure- thra in such a manner, that one third of its thickness is situated^above the urethra, and two thirds below it; its shape is somewhat pyriform, and its consistence be- tween cartilage and ligament. 3. The Urethra.—The curve should be carefully observed. The urethra begins at the neck of the blad- der; it is a continuation of that part of the bladder which in the erect posture is lowest. (1.) Its beginning is embedded in the prostate^ gland. (2.) Its membra- nous part is very short,—situated between the prostate gland and bulb of the urethra:—in dissecting, remark, that there is a firm fasciculus of fibres surrounding it, and connecting it and the prostate gland to the arcb.of the pubis ; this fasciculus gives support to the urethra, and is termed the ligamentum triangulare urethra, ft is sometimes described as a compressor muscle of the prostate gland. (2.) The urethra then enters the cor- pus spongiosum. 49 % *. The Corpus Spongiosum Urethra con- sists of a plexus of minute veins covered externally by a thin but uniform tendinous sheet; it surrounds the urethra from a short distance from the bladder to its extremity: at its beginning, it forms a con- siderable body of a pyriform shape, termed the Bulb of the Urethra; that part of the bulb which is below the urethra, is named the pendulous part of the bulb. The corpus spongiosum is expanded at its anterior extremity to form the glans penis. 5. The Glandule Anteprostat^e, or Cow- per's Glands, are two small glands of the size of peas, situated immediately before the prostate, and between the membranous part and bulb of the urethra. 6. The Vesiculje Seminales are two soft, whitish, knotted bodies, about three or four fingers- breadth in length, and one in breadth, and about three times as broad as thick: Situated between the rectum and lower part of the bladder obliquely, so that their inferior extremities are contiguous, and are affixed to the base of the prostate gland, while their superior extremities are at a distance from each other extending outwards and upwards, and termi- nating just on the inside of the insertion of the ureters in the bladder. 7. The two Vasa Deferentia are seen running betwixt the vesicula seminales, and united to them arid to the base of the prostate. Observe that part of the bladder, left between these tubes, and con- nected by cellular substance to the rectum, which is pierced when the bladder is punctured from the latter part. E 50 8. The Corpora Cavernosa Penis arise, on each side, by a process named the Crus, from the ramus and from the tuber ischii, ascend along the ischium and pubis, and are united immediately before the cartilaginous arch of the pubis ;—they are covered by a strong, white, shining, fibrous, ligamento-ten- dinous substance, which is very elastic. Internally they are cavernous, and are separated from each other by a septum, which, from being perforated, is named Septum pectiniforme. By the union of the two corpora cavernosa, two grooves are formed:—(1.) A smaller one above, in which two arteries pass, a large vein or two betwixt them, and some large twigs of nerves. (2.) A larger groove below, which receives the urethra. 9. The Vesica, Urinaria, or Urinary Blad- der, is situated within the pelvis, immediately behind the ossa pubis, and before the rectum. It is covered on its upper and back part by a reflection of peritoneum: in front and below (where it is con- tiguous to the rectum), it is connected by cellular membrane to the surrounding parts. Shape, oval, but flattened before and behind, and, while in the pel- vis, somewhat triangular. Divided into the fundus or bottom, corpus or body, and cervix or neck. In the contracted state, the fundus is the broadest and roundest part, but, when distended, the cervix is broader than any other part. At the top of the blad- der, above the symphysis pubis, may be observed, the superior ligament of the bladder, consisting of the Urachus, a ligamentous cord, which runs up between the peritoneum and linea alba, as far as the 51 navel*, and two of the ligamentous cords, which are the remains of the umbilical arteries, and run up from the sides of the bladder.—The ligamentum inferius vesica connects the bladder to the upper and inner side of the ossa pubis. Observe the parts of the bladder not covered by pe- ritoneum; as they are the situations of surgical opera- tions. These are the whole anterior surface, lying against the pubis, and rising above it, when the blad- der is distended, so that it may be punctured above the pubis;—the sides, at the very lowest part of which the cut is made in the lateral operation of lithotomy, and where the viscus may be punctured from the perine- um ;—and the inferior surface, resting on the rectum, and allowing us to puncture from it. Observe also the direction of the axis of the bladder, in conformity with which all instruments should be introduced: this is in a line drawn from the navel to the os coccygis. 10. The entrance of the ureters.into the bladder on the outside of the vesicula seminales. 11. The rectum, following the curve of "the os sa- crum, and os coccygis. 12. The prepuce is a fold of skin forming a sheath or covering for the glans penis. It makes a duplica- ture extending along the flat part of the glans from its basis to the orifice of the urethra, termed Frjenum Pr^putii. To have a more connected view of the relative situa- tion of these important parts, one side of the pelvis * In the foetus, it is a prolongation or production of the coats of the bladder 52 should now be removed, by dividing the symphysis pu- bis, and by sawing through the os ileum, or separating it at its junction with the sacrum. By carefully re- moving all the cellular membrane, the student will be enabled more accurately to examine the situation of the parts above described. OF THE VESSELS AND NERVES CONTAINED WITHIN THE PELVIS. I. arteries. The A. Iliaca Interna, having left the trunk of the iliaca communis, passes immediately into the pelvis, where it gives off several large arteries. 1. A. Ileo-Lumbalis supplies the psoas and iliacus internus muscles. 2. A. Sacra Laterales, two or three small ves- sels which supply the sacrum, cauda equina, and neigh- bouring parts. 3. A. Glutea (or iliaca posterior), a very large branch, passes out of the pelvis through the upper part of the sciatic notch to supply the haunch, but, in its passage, it gives some branches to the os sacrum, os coccygis, the rectum, and the muscles situated within the pelvis. 4. A. Sciatica passes out of the pelvis by the sci- atic notch, and below the pyriformis muscle to supply the hip: in its passage it gives branches to the neigh- bouring parts. 5. A. Pudica (pudenda communis or interna) is 53 the branch of the internal iliac, which is more imme- diately destined to supply the parts of generation, pe- rineum, and lower part of the rectum : it goes out of the pelvis above the superior sacro-sciatic ligament, twists round it, and re-enters the pelvis above and before the inferior sacro-sciatic ligament; it then descends on the inside of the tuber ischii, ascends on the inner surface of the rami of the ischium and pu- bis, and, reaching the root of the penis, divides into two branches. (1.) A. Perinei, a branch which, after giving twigs to the bulb of the urethra and neighbouring muscles, enters the crus of the penis, and subdivides into branches which pass to both extremities of the crus. (2.) A. Dorsalis Penis, passes under the arch of the pubis, runs along the dorsum penis, and is distri- buted to the integuments. In its course the pudic artery gives off many branches. (1.) While in the pelvis, it gives twigs to the blad- der, prostate, and rectum. (2.) A. Hjemorrhoidales Externa come from the pudic while passing by the anus. (3.) A. Transversa Perinei, following the course of the transversus perinei muscle. 6. A. Obturatrix descends on the inside of the psoas muscle, passes through the foramen in the ob- turator ligament to the muscles on the inside of the thigh. 7. A. Hypogastrics, which in the foetus sends off the umbilical artery, is in the adult continued only e 2 54 to the side of the bladder, to which it gives branches; in the female, it enters the neck of the uterus, and gives branches to the vagina. You must not expect to meet with uniformity in the distribution of these vessels in all subjects: sometimes the gluteal and pudic arteries come off by one trunk, sometimes the pudic and sciatic, &c. &c 2. VEINS. The veins attend the arteries and their ramifica- tions; they unite to form the internal iliac vein, except the veins from the rectum, named Hamorrhoidales, which ascend along its back-part to join the inferior mesenteric vein. 3. NERVES. The nerves met with in this dissection consist of numerous twigs sent off from the lumbar and sacral nerves to supply the parts about the pelvis. But, in this dissection, we meet with three pair of large nerves, which have their course through the pel- vis, and pass to the thigh. 1. Course of the Anterior Crural Nerve while in the pelvis. The anterior crural nerve is formed by branches of the first, second, third, and fourth lumbar nerves; at its origin, it lies under the psoas magnus, and, as it descends, passes betwixt the psoas magnus and iliacus internus, till, having passed under Poupart's ligament, it emerges from betwixt those muscles, and appears on the outer side of the inguinal artery. 55 2. Course of the Obturator Nerve within the pelvis. This nerve is formed by branches of the se- cond, third, and fourth lumbar nerves: it lies under the internal border of the psoas magnus, descends in- to the pelvis, and goes obliquely downwards, to ac- company the obiurator artery through the thyroid hole. 3. Course of the Great Sciatic Nerve within the pelvis. This nerve arises by branches from the fourth and fifth lumbar, and three first sacral nerves, which unite together to form the largest nervous trunk in the body. The nerve passes be wixt the pyriformis and gemini, and thus escapes from the back-part of the pelvis by the sciatic notch. Some- times one of the branches goes through the pyrifor- mis, and joins the sciatic trunk at the back of the pelvis. OF THE SCROTUM. The scrotum consists externally of a loose, rugose skin, and internally of condensed cellular membrane, which has been described as a muscle, under the name of Dartos. On dividing the anterior part of the scrotum, on ei- ther side of the raphe, we expose, 1. The Testicle, a gland of an oval flattened form, covered by the tunica vaginalis, having on its upper edge an appendage termed Epididymis. 2. The Spermatic Chord, connecting the testicle to the abdominal ring. It consists of, a, The spermatic artery, a branch of the aorta; this 56 divides into several branches, which ehter the upper edge of the testicle. b, The spermatic veins, which form a plexus, that terminates in the abdomen, in a single vein. c, The spermatic nerves, which come from the in- tercostal and lumbar nerves. d, The vas deferens, or excretory duct of the testi- cle ;—this is situated in the back-part of the chord, and is distinguished by its firm cartilaginous feel. e, The spermatic absorbents. f, These parts are all connected by cellular mem- brane, and by the tunica vaginalis, which is covered by a thin muscle. g, The cremaster;—this arises from the obliquus descendens internus, and is lost on the tunica vagina- lis. ^ . CHAP. III. DISSECTION OF THE ORGANS OF GENERA- TION IN THE FEMALE. PREVIOUS to the dissection, it will be proper t© examine the external parts. The Mons Veneris is a rounded prominence, covered with hairs after puberty, situated at the lower part of the belly, and arising on each side gradually 57 irom the groins; it consists of the common integu- ments, with an additional quantity of cellular and adipose substance, and lies upon the fore-part of the ossa pubis. From the inferior part of the mons veneris arise The Labia Externa, called also the labia or ala pudendi:—they are continued downwards and forwards in the direction of the symphysis pubis, and terminate in the perineum anterius: they consist of integuments, cellular substance, and fat,—are thicker above than below,—and are red and vascular on their inner side. The places where the labia are joined to each other above and below, are termed Commis- sures. The longitudinal cavity or fissure, situated betwixt the labia, and extending from the mons veneris to the perineum anterius, is sometimes called the Sinus Pudoris ; it is broader above than below, and con- tains several other parts. On separating the labia, we see, immediately below the superior commissure, The Clitoris, a red projecting body, situated be- low the arch of the pubis, and partly covered by its Prepuce: The prepuce is a fold of skin, continued from the inner surface of the labia, so as to cover the superior and lateral parts of the clitoris.—The clitoris resembles the penis of the male, and consists of two cavernous bodies; these cannot, however, be traced in this stage of the dissection. That part of the body which forms an obtuse projection externally, is called the Glans. The Perineum Anterius is that portion of the 58 soft parts which extends from the inferior commis- sure of the labia to the anus. The Perineum Posterius is the space betwixt the anus and point of the os coccygis. The Nympha are two prominent doublings of the integuments, extending from the glans of the clitoris to the sides of the vagina. Their external side is continued from the inner surface of the labia, and from the prepuce of the clitoris, while their internal surface seems immediately continued from the fine, thin, vascular integuments covering the clitoris it- self; they are spongy, and consist internally of cellular and adipose substance. A little lower, we see the orifice of the urethra ; it is situated below the clitoris and arch of the pubis, betwixt the nympha, and above the orifice of the vagina: it consists of a small rising prominence like a pea, in the centre of which is a small opening or hole. On each side of the orifice of the urethra, we meet generally with the orifices of two mucous glands, which by some are named Cowper's Glands of the female. On separating the lower part of the labia pudendi, we see the Vestibulum, a space which leads to the vagina; it is bounded behind, by the caruncula myr- tiformes, or by the hymen in virgins; on the sides, by the labia; before, by the perineum anterius, which projects forwards, forming a kind of valve, so that a little pit is formed behind it, which is termed Fossa Navicularis, or Scaphoides. The Hymen, or Circulus Membranosus, is a thin and extensile membrane, formed by a doubling of 59 the inner surface of the vestibulum and lower part of the vagina, the entrance of which is by its means much contracted in virgins. It generally has an opening in its upper part, but it is completely rup- tured in the first coitus: its form is various, frequently semilunar, and then its base is attached to the vestibu- lum, while its cornua extend upwards as far as the sides of the urethra. After the destruction of the hymen, in married women, we see some irregular projections marking the orifice of the vagina, and termed Caruncul.* Myrtiformes: they are generally supposed to be the remains of the hymen, but are not exactly in the same situation. Behind these is the Vagina, or canal leading to the uterus; at the extremity of which may be felt pro- jecting the Os Internum Uteri, or Os Tinca, but it cannot be seen without dissection. The skin should now be divided on the side of the right labium, and the dissection should be carried from the groin to the side of the anus; the cellular mem- brane must be carefully removed, in order to expose the following parts. We find the Clitoris consisting of two spongy bodies termed Crura, which unite and form the bo- dy. The crus of each side is a cavernous body, arising from the ramus and upper part of the tubero- sity of the ischium, continued along the ramus of the os pubis, and uniting with its fellow opposite to the symphysis pubis. The body formed by the crura does not extend upwards, but forms a curve downwards to- wards the urethra; it is divided internally by the 60 >on each side. Septum Pectiniforme, and is attached to the sym- physis pubis by a suspensory ligament; it is invested by a ligamentous membrane. The muscles which are met with in this dissection consist of four pair, and two single muscles. The Erector Clitoridis," Tranversus Perinei, Levator Ani, Coccygeus, The Sphincter Ani, "I . , _ T_ 5- two single muscles. Sphincter Vagina, J 1. The Erector Clitoridis arises, fleshy and tendinous, from the tuber ischii, from the inside of the ramus of the os ischium, and from the ramus of the os pubis: It passes over the crus of the clitoris, and, be- coming tendinous, is lost upon it. Use: To draw the clitoris downwards and forwards, and, by compressing it, to propel the blood. Synonyma: First muscle of the clitoris;__Ischio- cavernosus;—Ischio-clitoridien. Arising from the same point, and surrounded by much cellular membrane, we find 2. The Transversus Perinei.—Its origin is the same as in the male. It is inserted into a ligamentous substance in the pe- rineum anterius, at the point where the sphincter ani and sphincter vagina meet. This ligamentous or tendinous substance deserves alention. .Here, as in the male, it is the point of union into which different muscles are inserted. Use: to sustain the perineum. 3. Surrounding the extremity of the vagina, and a 61 small part of the vestibulum, we find the Sphincter Vagina; it arises, anteriorly, from the crura of the clitoris on each side; it surrounds the orifice of the va- gina, and is Inserted into the ligamentous point of the perine- um, where the fibres of each side meet, and are con- nected with those of the transversi perinei, and with the sphincter ani. Use: To contract the mouth of the vagina, and com- press the plexus retiformis. Synonyma: Constrictor cunni;—Second muscle of the clitoris ;—Anulo-syndesmo-clitoridien. 4. The Sphincter Ani exactly resembles the same muscle in the male. 5. The Levator Ani resembles the same muscle of the male; it surrounds the sides of the vagina in part, and consequently assists in constricting and sup- porting it. 6. The Coccygeus is longer than in the male, from the greater transverse diameter of the inferior aperture of the pelvis. Under the fibres of the sphincter vagina, you will find the Plexus Retiformis, or Corpus Caverno- sum Vagina, a spongy body, consisting of cellular substance, interwoven with a number of convoluted blood-vessels; it arises from the sides of the clitoris, passes on each side of the extremity of the vagina, is not continued completely around it, but is lost on its posterior part. The Vagina is the canal leading from the vestibu- lum to the uterus. It lies betwixt the rectum and in- ferior surface of the urethra and bladder, and is con- F 6-2 • nected to them by cellular membrane. It is composed of fibrous substance, partly ligamentous, and perhaps in part muscular; its inner surface is rugose, vascular, and occupied by mucous glands. On slitting it up, We see, at its posterior extremity, the Os Uteri, a rounded projection, with a transverse fissure. The Uterus, or Womb.—This organ is best seen from the cavity of the abdomen. It is situated betwixt the bladder and rectum, to both of which it is connected by reflections of peritoneum; it is of the shape of a pear, somewhat flattened, inwardly hollow, outwardly of a whitish colour, and of a firm consistence. The broad upper part of the womb is called the Fundus Uteri, the narrower part is named the neck, or Cervix Uteri, and the intermediate part its Body. The uterus has four ligaments, two on each side: 1. The Ligamentum Teres, or Round Ligament. It is a round long cord, extending from the side of the fundus uteri, and passing through the abdominal ring, to be lost in the groin. The Ligamentum Latum, or Broad Ligament, is a broad fold of peritoneum, reflected from the body of the uterus, and connecting it on the sides of the pelvis. The uterus, together with its two broad ligaments, divides the pelvis into an anterior and posterior half; in the former of which is the bladder, and in the latter the rectum. The duplicature of the broad ligament encloses the Fallopian tube, ovary, and round liga- ment. The Fallopian Tubes are two. Each tube is con- tained in the upper part of the doubling of the broad 63 ligament; it goes out from the fundus of the womb, and is a slender hollow tube: its outer end is curved down- wards and backwards, and terminates by a broad fring- ed extremity, termed Morsus Diaboli, or the Fim- bria__This broad extremity is connected to the next( pair of organs. The Ovaria are two small oval bodies, white and flat, situated by the sides of the uterus, and inclosed in the posterior fold of the broad ligament behind the Fal- lopian tube; each ovarium is connected to the fundus uteri by a short round ligament. The Bladder is situated before the uterus, and is described in the preceding chapter. The Urethra is short in females, and near the blad- der is surrounded by a spongy fleshy substance,—is con- nected to the cartilaginous arch of the pubis by the liga- mentum inferius vesica. The Ureter descends from the kidneys over the psoas muscle ; it runs for some space betwixt the blad- der and vagina, and at last perforates the bladder near the neck. The Rectum lies behind the uterus.—See the pre- ceding chapter. To obtain a more satisfactory knowledge of the rela- tive situation of the parts, the left side of the pelvis should be removed as in the male, and the parts exa- mined in that situation. 64 CHAP. IV. DISSECTION OF THE THIGH. SECT. I. OF THE ANTERIOR PART OF THE THIGH. § 1. OF the fascia, cutaneous vessels, and nerves. BENEATH the integuments common to every part of the body, you will find a strong fascia, or aponeurotic expansion, investing the whole thigh. This expansion is named the Fascia Lata Femoris; it consists part- ly of tendinous, partly of ligamentous fibres; it sur- rounds and covers all the muscles, and sends septa or partitions between them:—It is very strong, smooth, and tendinous on the outer part of the thigh; but, on the anterior and inner part, it is very thin, and of a cel- lular texture. Therefore, if you wish to demonstrate the whole extent of this fascia, it>shoukl be first expos- ed on the outside of the thigh, and the dissection should be continued very carefully inwards on the fore-part, where it is with difficulty distinguished from the com- mon cellular membrane. But, in removing the common integuments from 65 the fore-part of the thigh, it will be proper to attend to some parts which are situated above the fascia. 1. The Vena Saphena Major is seen running up in the inside of the knee and thigh. At first it lies very superficial, betwixt the skin and fascia, and in- volved in the intermediate cellular membrane. As it ascends, it is gradually enveloped by the fibres of the fascia, and then sinks beneath it to join the femoral vein about an inch below Poupart's ligament:—In its course it is joined by several cutaneous veins. 2. Immediately under the true skin, and more su- perficial than the veins or nerves, you may occasionally perceive the Lymphatic Vessels running, like lines of a whitish colour, to enter the inguinal glands : they are more numerous on the fore-part, than on the out- side of the thigh. 3. Several Cutaneous Nerves are seen ramify- ing above the fascia. They all come from the lumbar or anterior crural nerve, pierce the fascia about the lower part of the abdomen and groin, and are distri- buted to the groin, and integuments on the fore-part of the thigh. The fascia may now be exposed distinctly. Ob- serve how extensively it arises from the bones, ten- dons, and ligaments. On the anterior and superior part of the thigh, it arises from Poupart's ligament*, * At this part the fascia of the thigh is covered by a more superficial expansion, which lies over the lower part of the apo- neurosis of the external oblique muscle, completely covers the crural arch, and descends some little way beyond the bend of the thigh. It has been called the superficial fascia. It covers the absorbent glands, &c at the gro n, and often consists of several F 2 66 from the os pubis, from the descending ramus of that bone, and from the ascending ramus and tuberosity of the ischium;—behind, and on the outside, from the whole spine of the ileum, and from the sacro-sciatic ligaments. It receives a number of fibres from a muscle belonging to it, viz. the tensor vagina femoris, and from the tendon of the gluteus maximus;—it passes down over the whole thigh, is firmly fixed to the linea aspera, to the condyles of the femur, and to the patella, and is continued over the knee, to be attached to the heads of the tibia and fibula, after which it forms the fascia of the leg. On the upper and anterior part of the thigh, there is a slight hollow, where the great vessels descend un- der the crural arch. The fascia lata forms just on the outside and upper part of this, a crescent-shaped fold, called its semilunar edge, which is strongly connected to the crural arch, and sometimes contributes to the strangulation in femoral hernia. The fascia should now be dissected back; and, in lifting up the thicker part of it, which covers the out- side of the thigh, you may observe that it is composed of two lamina of fibres: the fibres of the outer lamina run in circles round the thigh, while those on the in- side, which are stronger, and more firmly connected, run longitudinally. layers separated by three glands and adipose substance. It has rather the appearance of condensed cellular membrane, than of a tendinous fascia, 67 §2. MUSCLES SITUATED ON THE FORE-PART ANB INSIDE OF THE THIGH. These are nine in number. 1. The Tensor Vagina Femoris—Arises, by a narrow, tendinous, and fleshy origin, from the external part of the anterior superior spinous process of the os ileum : it forms a considerable fleshy belly. Inserted into the inner side of the great fascia, where it covers the outside of the thigh, and a little below the trochanter major. Situation: Its origin lies between the origin of the sartonus, and the anterior fibres of the gluteus medius, betwixt which muscles it descends; it does not lie ex- ternal to the fascia of the thigh, but is inclosed in a du- plicature of it; its insertion lies anterior to that part of this membrane which arises from the tendon of the gluteus maximus. Use: To stretch the great fascia of the thigh, to assist in the abduction of the thigh, and in its rotation inwards. Synonyma: Musculus fascia lata;—Fascialis ;—- Mcmbranosus;—Ilio-aponeuri-femoral. 2. The Sartorius—Arises, by short tendinous fi- bres, from the anterior superior spinous process of the os ileum, soon becomes fleshy, extends obliquely across the thigh, and passes behind the inner condyle. Inserted, by a broad and thin tendon, into the inner side of the tibia, immediately below its anterior tu- bercle. Situation: Its origin lies between that of the tensor 68 vagina femoris, and the outer attachment of Poupart's ligament, and above the anterior fibres of the iliacus in- ternus. It lies before the muscles of the thigh, cross- ing them like a strap about two inches in breadth; it runs down for some space upon the rectus femoris, passes over the vastus internus, and then over the tri- ceps adductor longus. At the lower part of the thigh, it runs between the tendon of the triceps adductor mag- nus, and that of the gracilis.—In all this course, it is firmly bound down by the common fascia of the thigh. It is inserted above the tendons of the gracilis and semi- tendinosus, over which it sends an aponeurotic expan- sion. Use : To bend the leg obliquely inwards on the thigh, and to bend the thigh forwards. Synonyma: Longissimus femoris;—Ilio-creti-tibial. 3. The Rectus Femoris—Arises, by a strong ten- don, from the inferior anterior spinous process of the os ileum; and, by another strong tendon, from the dor- sum of that bone a little above the acetabulum, and from the capsular ligament of the hip-joint. The two tendons soon unite, and send off a large belly, which runs down over the anterior part of the thigh, forming a complete penniform muscle, and terminates in a flat but strong tendon, which is Inserted into the upper extremity of the patella; where a thin aponeurosis is sent from it over the fore- part of that bone, to terminate on the strong ligament which connects the lower part of the patella to the tibia, and is called Ligamentum Patella. Situation: To expose the tendinous origins of this muscle, the origins of the sartorius and tensor vagina 69 femoris must be raised; and then that tendon, which proceeds from the inferior spinous process, may be seen partly covered with the outer edge of the iliacus internus, while the other tendon is exposed by raising the anterior and inferior fibres of the gluteus minimus. The fleshy belly, at its uppermost part, is covered by the sartorius, and, to allow that muscle to slide over it, is tendinous; below this, it is situated superficially, im- mediately under the fascia, runs down over the vasti and cruraus ; and on its posterior surface, where it is in contact with those muscles, it is tendinous. Its in- sertion lies between the two vasti. Use: To extend the leg on the thigh, and to bend the thigh on the pelvis; to bring the pelvis and thigh forwards on the leg. Synonyma: Rectus cruris;—Rectus anterior;—Gra- cilis anterior;—Ilio-rotulien. Under the rectus, and partly covered by it, there is a large mass of flesh, which, at first sight, appears to form but one muscle. It may, however, be divided into three; the separation on the external surface is not generally very evident, but, by following the course of the vessels which enter this mass, and by cutting through perhaps a few fibres externally, you will discover the line of separation; and this separation, as you pro- ceed deeper with your dissection, will become very dis- tinct. The three muscles are named vastus externus, vastus internus, and cruraus: at the upper and middle parts of the thigh, they may be separated very distinct- ly ; but for two or three inches above the condyles, they are connected inseparably. 4. The Vastus Externus—Arises, tendinous and 70 fleshy, from the anterior surface of the root of the tro- chanter major, from the outer edge of the linea aspera, its whole length,—from the oblique line running to the external condyle,—and from the whole external flat surface of the thigh bone. The fleshy fibres run ob- liquely forwards. Inserted into the external surface of the tendon oi the rectus cruris, and into the side of the patella:— Part of it ends likewise in an aponeurosis which passes over the side of the knee to the leg, and is firmly fixed to the head of the tibia, closely adhering to the capsule of the knee-joint. Situation: This muscle forms the large mass of flesh on the outside of the thigh ; it is in part concealed by the rectus: on its outer surface it appears tendi- nous at its upper part, and fleshy lower down; on its internal surface, it is fleshy above and tendinous below;—it laps over the outside of the cruraus, where it arises from the linea aspera; it is situated anterior to the tendinous insertion of the gluteus maximus, and to the origin of the short head of the biceps flexor cruris. Use: To extend the leg, or to bring the thigh for- wards upon the leg. 5. The Vastus Internus—Arises, tendinous and fleshy, from the fore-part of the root of the trochan- ter minor, from all the upper edge of the linea aspera from the oblique line running to the inner condyle, and from the whole internal surface of the thigh bone. Its fibres descend obliquely downwards and forwards. Inserted into the lateral surface of the tendon of the 71 rectus cruris, and into the side of the patella; it also sends off an aponeurosis, which is continued down to the leg, and covers the inner part of the capsule of the knee. Situation: This muscle embraces the inside of the femur in the same manner as the last-described muscle does the outside, but it is much smaller;—it is also in part covered bv the rectus. At its upper part the sartorius passes over it obliquely; it laps over the cruraus, and is separated from it with greater diffi- culty than the vastus externus is. Where it arises from the root of the trochanter, it lies anterior to the common tendon of the iliacus internus and psoas mag- nus; and where it arises from the linea aspera and oblique line, it is situated anterior to, and in contact with, the insertions of the pectineus and triceps ad- ductor femoris. Like the vastus externus, its outer surface is tendinous above, while below its inner sur- face is tendinous, and the fleshy fibres pass obliquely from the one tendinous expansion to the other. Use : Same as the last. 6. The Cruraus, or Crulalis—irises, fleshy, from between the two trochanters of the os femoris, from all the fore-part of the bone, and from the out- side a6 far back as the linea aspera; but from the in- side of the bone it does not arise, for between the fore- part of the femur and the inner edge of the linea as- pera, there is a smooth plain surface, of the breadth of an inch, extending nearly the whole length of the bone, from which no muscular fibres arise. Inserted into the posterior surface of the tendon of the rectus, and upper edge of the patella. 72 Situation: The principal part of this muscle is lap- ped over, and concealed, by the bellies of the two vasti; and the small part, which is seen projecting be- tween the anterior edges of those muscles, lies behind the belly of the rectus cruris. Use: Same as the last. Synonyma: These three muscles are described by Dumas as a triceps, which he names Tri-femoro ro- tulien. 7. The Gracilis arises, by a broad thin tendon, from the lower half of that part of the os pubis which forms the symphysis, and from the inner edge of the descending ramus:—It soon grows fleshy, and forms a belly, which, becoming narrower as it descends, terminates in a tendon, which passes behind the inner condyle of the thigh bone, and is reflected forwards, to be Inserted in the inside of the tibia. Situation: It arises from the os pubis on the inside of the origins of the triceps adductor femoris, lying betwixt it and the crus penis; from the pubis to the knee it runs immediately under the integuments on the inside of the thigh ; it is inserted below the ten- don of the sartorius, and above that of the semitendi- nosus. Use: To bring the thigh inwards and forwards, and to assist in bending the leg. Synonyma: Gracilis interior ;—Rectus interior ;__ Sous-pubi-creti-tibial. 8. The Pectinalis—Arises, fleshy, from that ridge of the os pubis which forms the brim of the 73 pelvis, and from the concave surface below the ridge: It forms a thick flat belly, Inserted, by a flat tendon into the linea aspera, im- mediately below the lesser trochanter. Situation: Its origin lies on the inside of the belly of the psoas magnus, where that muscle slides over the brim of the pelyis, and on the outside of the origin of the adductor longus:—It descends between the lower edge of the psoas, and the upper edge of the adductor longus; and it is inserted between these two muscles, and posterior to the origin of the vastus internus. Use: To bend the thigh forwards, to move it in- wards, and to perform rotation, by turning the toes out- wards. Synonyma: Pectinaus;—Pubio-femoral. 9. The Triceps Adductor Femoris consists of three distinct muscles, which, passing from the pelvis to the thigh, lie in different layers upon one another, and have nearly the same action. (1.) The Adductor Longus—Arises, by a short strong tendon, from the upper and inner part of the os pubis, near its symphysis;—forms a large trian- gular belly, which, as it descends, becomes broader, but less thick. Inserted, tendinous, into the middle part of the linea aspera, occupying rather more than one-third of its length. Situation: It arises betwixt the pectinalis and gra- cilis, and above the adductor brevis :—The upper edge of its belly ranges with the lower edge of the pectina- lis ; and its insertion lies posterior to the origin of the g 74 vastus internus, and anterior to the insertion of the ad- ductor magnus. Synonyma: Adductor primus;—Triceps primus;— long head of the triceps;—Spino-pubio-femoral. (2.) The Adductor Brevis—Arises, fleshy and tendinous, from the os pubis, between the lower part of the symphysis pubis, and the foramen thyroideum:—it forms a fleshy belly, Inserted, tendinous, into the upper third of the linea aspera. Situation: Its origin lies under the origins of the pectinalis and adductor longus, and on the outside of the tendon of the gracilis:—Its belly descends behind the belly of the pectinalis, and behind the superior fibres of the adductor longus; and its largest part is therefore concealed, but a small part appears between the lower edge of the pectinalis, and upper edge of the adductor longus :—It is inserted behind those muscles, but before the adductor magnus. Synonyma: Triceps secundus;—Adductor secun- dus ;—Short head of the triceps ;—Sous-pubio-femoral. (3.) The Adductor Magnus—Arises, principally fleshy, from the lower part of the body, and from the descending ramus of the os pubis, and from the as- cending ramus of the ischium, as far as the tuberosity of that bone. The fibres run outwards and down- wards, having various degrees of obliquity. Inserted, fleshy, into the whole length of the linea aspera, into the oblique ridge above the internal con- dyle of the os femoris, and, by a roundish long tendon, into the upper part of that condyle. 75 Situation: This large muscle arises behind and be- low the two other adductors; it forms a flat partition betwixt the muscles on the fore and back parts of the thigh;—its insertion lies behind the insertions of the long and short adductors, and on the inside of the tendinous insertion of the gluteus maximus, and of the origin of the short head of the biceps flexor cru- ris : the superior fibres which cross the thigh transverse- ly run along the lower edge of the quadratus femoris. Use : To approximate the thighs to each other;— to roll them outwards. The two anterior heads will bend the thigh; the posterior will extend it, if it be bent forwards. Synonyma: Adductor tertius et Adductor quartus; —Triceps tertius ;—Great head of the triceps ;—Is- chio-pubi-femoral. § 3. arteries, veins, and nerves on the fore- part AND INSIDE OF THE THIGH. 1. ARTERIES. TkE Femoral Artery may be said to pass along the inside of the thigh, where it emerges from under Poupart's ligament; it lies cushioned on the fibres of the psoas magnus, is called the Inguinal artery, and is very nearly in the mid space between the angle of the pubis, and the anterior superior spine of the ileum, nearer, however, by a finger's breadth to the former; having left the groin, it assumes the name of Femoral, and, in its course down the thigh, runs over the following- muscles:—The pectinalis, part of 76 the adductor brevis, where that muscle projects be- twixt the pectinalis and adductor longus; the whole of the adductor longus, and about an inch of the adduc- tor magnus: It then slips betwixt the tendon of the adductor magnus and the bone, and, entering the ham, becomes the Popliteal artery.. To find the artery in any part of its course from the crural arch to the ten- dinous opening, turn out the foot, ascertain the place of that vessel at the crural arch, according to the above description, and then draw a straight line downwards. —In this course, it has the belly of the vastus internus situated on its outside; it lies between the origin of that muscle, and the tendinous insertion of the muscles over which it crosses; and there is a strong interlacing of the tendinous fibres, forming a deep groove for the ar- tery; it is also invested by a firm sheath,Which con- sists of condensed cellular membrane, intermixed with some tendinous fibres:—For some inches below Pou- part's ligament, this artery is on its fore-part only co- vered by cellular substance, absorbent glands, and the general fascia of the thigh; but, meeting with the in- clined line of the sartorius, it is, during the rest of its course, covered by that muscle. It perforates the ten- don of the adductor magnus, at the distance of rather more than one-third of the length of the bone from its lower extremity. Observe that in popliteal aneurism the artery may be taken up either at the upper or inner, the lower of outer, margin of the Sartorius, or immediately behind that muscle: of which situations the first is the best, the second next best, and the third by far the least eligible i t Branches of ihe Femoral Artery*. The A. Profunda comes off from the femoral artery at the distance of three or four inches from Poupart's ligament; it is nearly as large as the femoral itself, runs down for some little way behind it, and terminates in three or four branches, which, perforating the tri- ceps adductor, are named Arteria Perforantes. These, ramifying in every direction, supply all the great mass of muscles situated on the back-part of the thigh, and inosculate largely with the sciatic, gluteal, and obturator arteries. The profunda also sends off two considerable branches, which, encircling the upper part of the thigh, are named Circumflexa Interna, and Circumflexa Externa. The profunda is the only branch of the femoral ar- tery which is constant in its size and situation; for though, during the whole of its course, the femoral gives off branches to the muscles, yet these muscular arteries vary much, sometimes coming off from the great artery, sometimes from the profunda, sometimes coming off as a large single trunk which subdivides, while at other times there are three or four distinct ar- teries. The branches of the femoral artery may be enume- rated as follows:—1. Some twigs to the inguinal glands, and some to the external parts of generation, named * The Epigastrica and Circumflexa ilii are before described as branches of the inguinal artery. 6 3 78 Pudica Externa. 2. Muscularis interna. 3. Muscu- laris externa. 4. Profunda. The Obturator Artery, arteria obturatrix, which is a branch of the internal iliac artery, passes through the notch at the upper part of the foramen thyroideum, and ramifies on the deep-seated muscles at the upper and inner part of the thigh. _ 2..VEINS. The Femoral Vein adheres closely to the femoral artery in its passage out of the abdomen, and accompa- nies it in its course down the thigh, where it passes un- der Poupart's ligament; it lies on the inside of the ar- tery, but, as it descends, it turns more and more poste- riorly, so that where they perforate the tendon of the adductor magnus, the vein is situated fairly behind the artery. Its branches correspond to those of the femoral ar- tery ; but about an inch below Poupart's ligament, it receives the vena saphena major, to which there is no corresponding artery. The Obturator Vein accompanies the obturator artery, and has the same distribution. 3. NERVES. Nervus Cruralis Anterior, or the Anterior m-ural nerve, where it passes from under Poupart's li- gament, lies about half an inch on the outside of the femoral artery; it immediately divides into a number of branches, which supply, the muscles and integu- 79 ments on the fore-part and outside of the thigh: A considerable branch, however, accompanies the femo- ral artery, crosses that vessel where it is about to per- forate the adductor magnus, runs behind the sartorius, and appears as a cutaneous nerve on the inside of the knee; proceeding downwards on the inside of the leg, it is largely distributed over the tibia, is intricated with the vena saphena major, and terminates on the inner ankle, and upper part of the foot. This branch is named Nervus Saphenus, or Cutaneus Longus. Another branch, which is distributed to the vastus in- ternus, generally runs for some way in company with the femoral vessels. Nervus Obturator, or the obturator nerve, is found accompanying the obturator artery and vein; it has the same distribution, and some branches extend as far as the internal condyle of the thigh bone, and com- municate with the nervus saphenus. SECT. II. OF THE POSTERIOR PART OF THE THIGH. § 1. OF THE FASCIA. Above that part of the great fascia which invests the thigh belvnd, we meet with several cutaneous nerves; these are of little importance;—they have their origin either from the lumbar nerves, and come over the spine of the os ilium, or from the great sciatic 80 qerve, and emerge under the lower margin of the glu- teus maximus. Other twigs come from the sacral nerves, and from the sciatic in its course down the thigh. § 2. MUSCLES SITUATED ON THE BACK-PART OF THE THIGH. These are eleven. On removing the integuments and fascia from the hip, we denude, 1. The Gluteus Maximus—It arises, fleshy, from the posterior third of the spine of the os ileum, from the whole lateral surface of the sacrum, below the posterior spinous process of the ileum; from the back-part of the posterior or inferior sacro-sciatic liga- ment*, over which the edge of this muscle hangs in a folded manner, and fmm the lateral surface of the os coccygis. The fleshy fibres proceed obliquely forwards and downwards, forming a thick broad coarse muscle, and, converging gradually, terminate in a strong flat tendon. This tendon slides over the posterior part of * The sacro-sciatic ligaments are two in number; they pass between the ischium and sacrum. 1. The external or inferior, or posterior, sacro-sciatic ligament anses from the external edge of the transverse processes of the sacrum, descends obliquely, and is inserted into the tuberosity of the os ischium. ' 2. The internal, or anterior, arises from the edge of the trans verse processes of the sacrum, and of the os coccvgis- it nasses across on the inside of the external, and is inserted into the point af the spinous process of the ischium. 81 the trochanter major; sends off a great quantity of ten- dinous fibres, to be inseparably joined to the fascia lata of the thigh ; and is Inserted, into a rough surface at the upper and outer part of the linea aspera, immediately below the trochan- ter major; also very extensively into the fascia lata, which covers the former insertion. Situation: It is quite superficial, covering all the other muscles which are situated on the back-part of the hip, covering also the tuber ischii, and the tendons of the muscles which arise from that projection. Its insertion lies between the vastus externus and the ad- ductor magnus femoris, and immediately above the origin of the short head of the biceps flexor cruris :— so much adipose membrane is entangled with this muscle, that it is very difficult to dissect it clean, and quite impossible, if you do not dissect in the course of the fibres, which are divided into very large and strong fasciculi. Use : To restore the thigh, after it has been bent; —to rotate it outwards ; to extend the pelvis on the thigh, and maintain it in that position in the erect pos- ture of the body. Synony?na : Gluteus magnus ;—Gluteus major ;— Ilio-sacro-femoral. The muscle is now to be lifted from its origin, and left hanging by its tendon; remark the large bursa mu- cosa formed between the tendon and the trochanter major; and another between its insertion into the fas- cia and the tendon of the vastus externus. 2. The Gluteus Medius—Arises, fleshy, from 82 all the outer edge of the spine of the os ileum, as far as the posterior tuberosity; from the dorsum of the bone, between the spine, and semicircular ridge (which passes from the anterior superior spinous pro- cess to the ischiatic notch); also from the rough sur- face which extends from the anterior superior to the anterior inferior spinous process, and from the inside of a fascia which covers its anterior part. The fibres converge into a strong and broad tendon, which is Inserted into the upper and outer part of the great trochanter. Situation: The posterior pari of the belly and the tendon are concealed by the gluteus maximus, but the anterior and largest part of this muscle is superfi- cial, being only covered by a fascia; it lies behind the origin of the tensor vagina femoris, and above the belly of the pyriformis; it covers the gluteus minimus. Use: To draw the thigh bone outwards, or away from the opposite limb; to maintain the pelvis in a state of equilibrium on the thigh in progression, while the other foot is raised from the ground; by its poste- rior fibres to rotate the limb outwards; and by its ante- rior inwards. Synonyma : Ilio-trochantevien. Having lifted up this muscle from its origin, you will discover, 3. The Gluteus Minimus.—It arises, fleshy, from the semicircular ridge of the ileum, and from the dorsum of the bone below the ridge within half an inch of the acetabulum. Its fibres run 83 in a radiated direction towards a strong tendon, which is Interted into the anterior and superior part of the great trochanter. Situation: It is entirely concealed by the gluteus medius, and between their tendons there is a bursa mu- cosa. Use: Same as that of the preceding. Synonyma: Gluteus minor;—llio-ischii-trochante- rien. 4. The Pyriformis—Arises, within the pelvis, by three tendinous and fleshy origins, from the second, third, and fourth false vertebra or divisions of the sa- crum. It forms a thick belly, which passes out of the pelvis below the niche in the posterior part of the ileum (from which it receives a few fleshy fibres), and above the superior sacro-sciatic ligament. Inserted, by a roundish tendon, into the uppermost part of the cavity at the root of the trochanter ma- jor. Situation: Like the other small muscles of the hip, it is entirely concealed by the gluteus maximus; its belly lies behind and below the gluteus med^i^but is not at all covered by it, and above the superior gemel- lus. Its tendon is covered, at the place of insertion, by the posterior fibres of the gluteus medius. Some- v times the pyriformis is divided into two distinct mus- cles, by a branch of the great sciatic nerve. Use: To move the thigh a little upwards, and roll it outwards. Synonyma: Iliacus externus;—Sacro-trochanterien. 84 5. The Gemini consist of two heads, which are dis- tinct muscles. (1.) The superior arises from the back-part of the spinous process of the ischium. (2.) The inferior from the upper part of the tubero- sity of the os ischium, and the anterior surface of the posterior sacro-sciatic ligament. Inserted, tendinous and fleshy, into the cavity at the root of the trochanter major, immediately below the in- sertion of the pyriformis, and above the insertion of the obturator externus. Situation: Like the other muscles, they are covered by the gluteus maximus ; they lie below the pyrifor- mis, and above the quadratus femoris ; they are united by a tendinous and fleshy expansion, which forms a purse or sheath for the tendon of the obturator inter- nus Use : To roll the thigh outwards, and to bind down the tendon of the obturator internus. Synonyma: Gemelli;—Part of the marsupialis ;— Ischio-spini-trochanterien. Lying between the bellies of the gemini, you will perceive, 6. The Obturator Internus—It arises, tendi- nous and fleshy, from more than one-half of the in- ternal circumference of the foramen thyroideum, and from the inner surface of the ligament which fills up that hole ; its inside is covered by a portion of the levator ani; it forms a flattened tendon, which passes out of the pelvis in a sinuosity betwixt the spinous process and tuberosity of the ischium ; and, becoming rounder, is 85 Inserted into the pit at the root of the trochanter major. Situation: Its origin lies within the pelvis, and cannot be exposed till the contents of that cavity are removed; the tendon, where it passes through the notch in the ischium, is seen projecting between the two origins of the gemelli, and is covered by the gluteus maximus; but, farther forward, it is inclosed as in a sheath, and concealed by the gemelli, and is inserted between them. There is a bursa mucosa be- twixt the tendon of this muscle, and the surface of ischium over which it glides. Use : To roll the os femoris obliquely outwards. Synonyma: Marsupialis seu Bursalis ;—Intra-pel- vio-trochanterien. 7. The Quadratus Femobis—Arises, ten- dinous and fleshy, from an oblique ridge, which des- cends from the inferior edge of the acetabulum along the body of the ischium, between its tuberosity and the foramen thyroideum: its fibres run trans- versely, to be Inserted, fleshy, into a rough ridge on the back part of the femur, extending from the root of the greater trochanter to the root of the lesser. Situation: It is concealed by the gluteus maximus, lies below the inferior head of the gemini, and above the superior fibres of the adductor magnus ; its origin is in contact with the origin of the hamstring muscles. Use : To roll the thigh outwards. Synonyma : Tuber-ischio-trochanterien. On lifting up the quadratus femoris from its ori- gin, and leaving it suspended by its insertion, you H 86 discover, running in the same direction, the strong tendon of, 8. The Obturator Externus.—This muscle arises, fleshy, from almost the whole circumference of the foramen thyroideum, and from the external surface of the obturator ligament; its fibres pass outwards through the notch placed between the inferior margin of the acetabulum and the tuberosity of the ischium, wind around the cervix of the os femoris, adhering to the capsular ligament, and terminate in a strong ten- don, which is Inserted into the lowermost part of the cavity, at the root of the trochanter major, immediately below the insertion of the inferior head of the gemini. Situation : This muscle cannot be distinctly seen, until all the muscles which run from the pelvis to the upper part of the thigh are removed, both on the fore and back-part; its origin lies on the fore-part, and is concealed by the muscles situated there, as the pectinaus, triceps, he. and on the back-part the tendon is concealed by the quadratus femoris, and, when that muscle is removed, it is found to run along the lower edge of the inferior head of the gemini. Use : To roll the thigh bone obliquely outwards. Synonyma: Extra-pelvio-pubi-trochanterien. 9. The Biceps Flexor Cruris—Arises, by two distinct heads; the first, called the Long Head, arises in common with the semitendinosus, by a short tendon, from the outer part of the tuberosity of the ischium, and, descending, forms a thick fleshy belly. —The second, termed the Short Head, arises, ten- dinous and fleshy, from the linea aspera, immediately 87 below the insertion of the gluteus maximus; and from the oblique ridge running to the outer condyle, where it is connected with the fibres of the vastus externus. The two heads unite at an acute angle, a little above the external condyle, and terminate in a strong tendon, which is Inserted into a rough surface on the outside of the head of the fibula. Situation: The long head of this muscle is conceal- ed at its upper part by the inferior fibres of the gluteus maximus; below this, it is situated quite superficial, immediately under the fascia, running from the pelvis to the knee between the vastus externus and semiten- dinosus, and forming the outer hamstring.—The short head is partly concealed by the long head; its fibres arise from the linea aspera, between those of the ad- • ductor magnus and vastus externus;—ft forms the out- er hamstring. Use: To bend the leg, and particularly by means of its shorter head to twist the leg outwards in the bent state of the knee. Synonyma: Biceps cruris;—Ischio-femoro-peronien. 10. The Semitendinosus—Arises, tendinous, in common with the long head of the biceps, from the tu- berosity of the ischium; it has also some fleshy fibres arising from that projection more outwardly:—as it de- scends, it arises, for two or three inches, fleshy, from the inside of the tendon of the biceps; forms a thick belly, and terminates at the distance of three or four inches from the knee in a long round tendon, which, be- 88 coming flat, passes behind the head of the tibia, and is reflected forwards, to be Inserted into the anterior angle of that bone, some little way below its tubercle. Situation: This muscle, as well as the biceps, is co- vered above by the gluteus maximus; its belly lies be- tween the biceps flexor and gracilis, and is situated en- tirely superficial; its tendon is inserted below that of the gracilis: The belly of this muscle is intersected, about its middle, by a narrow transverse tendinous line. Use: To bend the leg backwards, and a little in- wards. Synony?na: Seminervosus;—Ischio-creti-tibial. 11. The Semimembranosus—Arises, by a strong round tendon, from the upper and outer part of the tu- berosity of the ischium; the tendon, soon becoming broader, sends off obliquely a fleshy belly; this muscle is continued, fleshy, much lower down than that last described.—The fleshy fibres terminate obliquely in another flat tendon, which passes behind the inner con- dyle, sends off a thin aponeurotic expansion under the inner head of the gastrocnemius, to cover the posterior part of the capsule of the knee-joint, and to be affixed to the external condyle: the tendon then becoming rounder, is Inserted into the inner and back part of the head of the tibia. Situation: This is a semi-penniform muscle; its origin lies anterior to the tendinous origin of the two last muscles,' and at the same time more outwardly, 89 being situated between them and the origin of the quadratus femoris :—its belly, in its descent, is at first concealed by the biceps and semitendinosus; but, at its lower part, it appears projecting between them. It lies in contact with the posterior surface of the tri- ceps magnus. Use: To bend the leg backwards. Synonyma: Ischio popliti-tibial. The two last-described muscles properly form the inner hamstring; but some enumerate among the ten- dons of the inner hamstring, the sartorius and gracilis. § 3. VESSELS AND NERVES ON THE POSTERIOR PART OF THE THIGH. ARTERIES. 1. Arteria Glutea, or Iliaca Posterior.— This is the largest branch of the internal iliac artery; it passes out of the pelvis at the upper part of the sci- atic notch. On raising the gluteus maximus and me- dius, this artery is seen coming over the pyriformis, betwixt the superior edge of that muscle and the in- ferior edge of the os ileum (where that bone forms the upper part of the sciatic notch), and immediately behind the posterior fibres of the gluteus minimus. The principal trunk passes under the gluteus medius, and ramifies on the dorsum of the os ileum; other large branches are also continued to the gluteus max- imus, and the muscles situated on the back-part of the pelvis. 2. Arteria Sciatica, vel Ischiatica, is another large branch of the internal iliac, which comes out \ H 2 90 from under the pyriformis, betwixt the lower edge of that muscle and the superior sacro-sciatic ligament; it lies upon tlje back-part of the hip, under the gluteus maximus;—its principal branches descend between the trochanter major and tuberosity of the ischium; it sends other twigs round towards the anus and peri- neum. Both these arteries inosculate with the other branch- es of the internal and external iliac. The Veins correspond exactly to the arteries. They terminate in the internal iliac vein. NERVES. Nervus Sciaticus, vel Ischiaticus, or the Great Sciatic Nerve, is seen coming out of the pelvis, along with the sciatic artery, below the pyriformis. It de- scends over the gemini and quadratus femoris in the hollow betwixt the great trochanter and the tuberosity of the ischium,—runs down the back-part of the thigh, anterior to, i. e. nearer the bone than the hamstring muscles; being situated between the anterior surface of the semimembranosus, and the posterior surface of the triceps adductor longus. After sending off the peroneal nerve, it arrives in the ham, and becomes the Popliteal Nerve. In this course it gives off several branches to the muscles and integuments. It sometimes perforates the belly of the pyriformis bv distinct trunks, which afterwards unite. 91 SECT. III. DISSECTION OF THE HAM AND FASCIA ON THE BACK- PART OF THE LEG. On removing the integuments from the back-part of the knee-joint and leg, we observe a Fascia, which covers the great vessels and the muscles. It is evi- dently continued from the great fascia of the thigh, is strengthened by adhesions to the condyles of the fe- mur, and to the head of the fibula, and is prolonged upon the muscles on the back of the leg. Upon dissecting back that part of the fascia which covers the ham, the Great Sciatic Nerve appears, lying between the outer and inner hamstring-muscles. This nerve, having given off branches about the ham, and to the integuments on the back of the leg, di- vides at some distance above the condyles of the fe- mur into two large branches. 1. The Greater Nerve continues its course betwixt the heads of the gastrocnemii muscles. In the ham it is named the Popliteal Nerve, and where it de- scends in the leg, the Posterior Tibial 2. The Lesser Nerve, which is the external branch, is named the Peroneal or Fibular Nerve ; it pass- es outwards and obliquely downwards, runs between the external head of the gastrocnemius, and the ten- don of the biceps flexor cruris; and sinks among the muscles which surround the head of the fibula. <*) 92 Branches of the Peroneal Nerve. (1.) Cutaneous branches are sent off from the pero- neal nerve at its uppermost part over the gastrocne- mius to the integuments in the back-part of the leg, and outer side of the foot. Branches also are distri- buted about the joint. (2.) A large branch, the Anterior Tibial Nerve, passes under the flesh of the peroneus longus and ex- tensor longus digitorum, where those muscles arise from the heads of the fibula and tibia; and comes in contact with the anterior tibial artery, which it accom- panies down the leg. (3.) Another branch passes into the upper extremity of the peroneus longus, and is continued in the sub- stance of that muscle for some space. It then emerges from beneath it, and continues its course under the muscles on the fore-part and outside of the leg; it pierces this fascia, and, becoming cutaneous, is lost on the ankle and upper surface of the foot. Below the great sciatic nerve, there is much cellu- lar membrane and fat, which being removed, the Great Popliteal Vein is exposed.' It adheres to the Popliteal Artery, which lies under it close upon the bone. Arteria Poplitea is the trunk of the Femoral, which assumes that name, after it has perforated the tendon of the triceps. It lies between the condyles of the femur, close upon the bone, and descends between the heads of the gastrocnemius. It runs over the po- pliteus, and under the gastrocnemius, that is, in the 93 erect position it is anterior to the gastrocnemius, and posterior to the popliteus: at the lower edge of the popliteus, the popliteal artery divides into the Anteri- or and Posterior Tibial Arteries. Branches. 1. Two Perforating Arteries come off from the artery immediately after it has entered the ham ;— they are small, and perforate from the ham to the fore- part of the thigh. 2. Articular Arteries are four or five small twigs, ramifying over the knee-joint and neighbouring muscles, inosculating with one another, and with the arteries below the knee. 3. Two branches are sent to the two heads of the gastrocnemii muscles; twigs are also given to the so- leus, plantaris, 8cc. The Popliteal Vein receives branches corres- ponding to those of the artery; it lies behind the artery in the erect posture. About two inches above the condyle, it receives the Vena Saphena Minor, which returns the blood from the outer side of the foot;—the trunk of this vein lies under the fascia. 94 CHAP. V. DISSECTION OF THE LEG AND FOOT. SECT. I. OF THE FORE-PART OF THE LEG AND FOOT. ON dissecting off the integuments from the fore-part of the leg, we find a strong fascia continued from the thigh; it adheres firmly to every projecting point of bone, to the head and spine of the tibia, and to the fibu- la; it grows thinner towards the lower part of the leg; but where it passes over the ankle, it again becomes very strong by its adhesions to the outer and inner ankle, and forms a strong Annular or Transverse Ligament, which binds down the tendons, and is evi- dently but a thicker and stronger part of the general fascia of the leg. This annular ligament seems to con- sist of two distinct cross bands, which, going from the point of the outer ankle and neighbouring part of the os calcis, are fixed to the malleolus internus, and to the inside of the os naviculare. Before removing the fascia, it will be proper to re- mark, 1. The vena saphena major, running upon the in- 95 side of the tibia, and accompanied by a cutaneous nerve, the nervus saphenus. 2. Several cutaneous nerves, branching on the outer and fore-part of the leg and foot, and derived from the nervus peroneus. The fascia should then be dissected off; and, in do- ing this, remark, that it is firmly attached to the bones, and also to the bellies of the muscles at the upper part of the leg, so that their surfaces appear ragged, where the fibres are separated which arose from the inside of the fascia : Remark also, that it sends down processes between the muscles; these are named intermuscular ligaments, or tendons ; they give origin to the fibres of all the muscles betwixt which they pass, connecting them together inseparably, so that the dissection is dif- ficult, and has a rough appearance. MUSCLES SITUATED ON THE FORE-PART AND OUT- SIDE OF THE LEG. These are six in number. 1. The Tibialis Anticus—Arises, principally fleshy, from the exterior surface of the tibia, from its anterior angle or spine, and from nearly half of the interosseous ligament; from these surfaces it continues to arise down two-thirds of the length of the bone ; also from the inner surface of the fascia of the leg, and from the intermuscular ligaments. The fleshy fibres descend obliquely, and terminate in a strong tendon, which crosses from the outside to the fore-part of the tibia, passes through a distinct ring of the annular liga- 96 ment near the inner ankle, runs over the aBtraguIus and os naviculare, and is Inserted into the upper and inner part of the os cu- neiforme internum, and the base of the metatarsal bone supporting the great toe. Situation: The belly is quite superficial, lying under the fascia of the leg on the outside of the spine of the tibia; the insertion of the tendon is concealed in part by the abductor and flexor brevis of the great toe. Be- tween the tendon of this muscle and the os cuneiforme, we find a small bursa mucosa. Use : To draw the foot upwards and inwards; or, in other words, to bend the ankle-joint. Synonijma: Tibio-sus-metatarsien. 2. Extensor Longus Digitorum Pedis— Arises, tendinous and fleshy, from the outer part of the head of the tibia; from the head of the fibula; from the anterior angle of the fibula almost its whole length ; and from part of the smooth surface between the anterior and internal angles; from a small part of the interosseous ligament; from the fascia and inter- muscular ligaments. Below the middle of the leg, it splits into four round tendons, which pass under the annular ligament, be- come flattened, and are Inserted into the root of the first phalanx of each of the four small toes, and expanded over the upper side of the toes as far as the root of the last phalanx. Situation: This muscle also runs entirely superfi- cial ; it lies between the tibialis anticus and peroneus longus, being firmly connected to them by intermus- 97 cular ligaments; but, at the lower part of the leg, it is separated from the tibialis anticus by the extensor pollicis longus, and from the peroneus longus by the peroneus brevis. Use : To extend all the joints of the four small toes; —to bend the ankle joint. Synonyma: Peroneo-tibi-sus-phalangettien commun. 3. Peroneus Tertius—Arises, fleshy, from the anterior angle of the fibula, and from part of the smooth surface between the anterior and internal an- gles, extending from below the middle of the bone downwards to near its- inferior extremity;—sends its fleshy fibres forwards to a tendon, which passes under the annular ligament in the same sheath as the exten- sor digitorum longus, apd is Inserted into the base of the metatarsal bone that supports the little toe. Situation : The belly is inseparably connected with the extensor longus digitorum, and is properly the outer part of it; it lies between that muscle and the peroneus brevis. The tendon runs down on the out- side of that tendon of the extensor longus digitorum which goes to the little toe. The whole of the muscle is superficial. Use: To assist in bending the foot. Synonyma: Nonus Vesalii;—Petit-peroneo-sus-meta- tarsien. 4. Extensor Proprius Pollicis Pedis—Arises, tendinous and fleshy, from part of the smooth surface between the anterior and internal angles of the fibula, and from the neighbouring part of the interosseous i 98 ligament, extending from some distance below the head of the bone to near its inferior extremity ; a few fibres also arise from the lower part of the tibia;— the fibres pass obliquely downwards and forwards into a tendon, which, inclining inwards, passes over the fore-part of the astragalus and os naviculare, and over the junction of the os cuneiforme internum and os cu- neiforme medium, to be Inserted into the base of the first and of the second phalanges of the great toe*. Situation : The belly is concealed between the tibi- alis anticus and extensor digitorum longus, and cannot be seen till those muscles are separated from one ano- ther ;—the tendon is superficial, running between the tendons of those two muscles. Use: To extend the great toe; and to bend the ankle. Synonyma : Extensor longus pollicis;—Peroneo-sus- phalanginien du pouce. The Peroneus Longus—Arises, tendinous and fleshy, from the fore-part and outside of the head of the fibula, and from the adjacent part of the tibia, from the external angle of the fibula, and from the smooth surface between the anterior and external angles as far down as one-third of the length of the bone from its lower extremity; also from the fascia of the leg and intermuscular ligaments. The fibres run obliquely outwards into a tendon, which passes behind the outer ankle, through a groove in the * N. B. It is to be understood, that the great toe has only two phalanges. 9? lower extremity of the fibula ; is then reflected forwards through a superficial fossa in the outside of the os cal- cis, passes over a projection, runs in a groove in the os cuboides, passes over the muscles in the sole of the foot, and is Inserted, tendinous, into the outside of the base of the metatarsal bone that sustains the great toe, and in- to the os cuneiforme internum. Situation : The belly is quite superficial; it lies be- tween the outer edge of the extensor longus digitorum and the anterior edge of the soleus, connected to both by intermuscular ligaments. The tendon is superficial where it crosses the outside of the os calcis, but, in the sole of the foot, is concealed by the muscles si- tuated there, and will be seen in the dissection of that part. Use: To extend the ankle-joint, turning the sole of the foot outwards. Synonyma : Peroneus maximus, vulgo, Peroneus pos- terior;—Peroneus primus, seu posticus;—Tibi-pero- neo-tarsien. 6. The Peroneus Brevis—Arises, fleshy, from the outer edge of the anterior angle of the fibula, and from part of the smooth surface behind that angle ; be- ginning about one-third down the bone, and continuing its adhesion to near the ankle; from the fascia of the leg, and from the intermuscular ligaments:—The fibres run obliquely towards a tendon, which passes through the groove of the fibula behind the outer ankle, being there inclosed in the same ligament with the tendon of the peroneus longus, then through a se- H 100 parate groove on the outside of the os calcis, and is Inserted into the external part of the base of the me- tatarsal bone that sustains the little toe. Situation: This muscle arises between the extensor longus digitorum and peroneus longus ; its belly is over- lapped, and concealed by the belly of the peroneus longus; but, as it continues fleshy lower down, it is seen, above the ankle, projecting on each side of the tendon of that muscle :—Below, it is separated from the peroneus tertius by that projection of the fibula which forms the outer ankle, and which is only covered by the common integuments. The tendon, where it passes through the groove of the fibula, lies under that of the peroneus longus, i. e. nearer the bone ; but it is soon seen before it, and, on the side of the os calcis, runs t above it. Use: Same as that of the peroneus longus. Synonyma: Peroneus medius vel anticus;—Perone- us secundus ;—Peroneus brevis;-—Grand peroneo-sus- metatarsien. MUSCLES ON THE UPPER PART OF THE FOOT. Only one muscle is found in this situation. Extensor Brevis Digitorum Pedis--Arises, fleshy, and tendinous, from the anterior and upper part of the os calcis, from the os cuboides, and from the astragalus; forms a fleshy belly, divisible into four portions; these send off four slender tendons, which are 101 Inserted, the first tendon, into the first phalanx of the great toe; and the other three into all the small toes except the little one, uniting with the tendons of the extensor digitorum longus, and being attached to the upper convex surface of all the phalanges. Situation: The belly of this muscle lies under the tendons of the extensor digitorum longus and peroneus brevis; it is not, however, concealed, but is seen projecting behind and betwixt these tendons; it as- sists in forming the tendinous membrane which in- vests the upper surface of all the phalanges of the toes. Use: To extend the toes. Synofiyma: It is sometimes described as two mus- cles, the extensor brevis pollicis pedis, and extensor brevis digitorum pedis ;—Calcaneo-sus-phalangettien commun. OF THE VESSELS AND NERVES IN THE FORE-PART OF THE LEG AND FOOT. 1. ARTERIES. Arteria Tibialis Antica.—The anterior tibial artery passes from the ham betwixt the inferior edge of the popliteus, and the superior fibres of the soleus, and then through a large perforation in the interos- seous ligament, to reach the fore-part of the leg; this perforation is much larger than the size of the ar- tery, and is filled up by the fibres of the musculus tibi- alis posticus, which may thus be said to arise from the., fore-part of the tibia.—The artery then runs down i 2 '**4 102 close upon the middle of the interosseous ligament, between the tibialis anticus and extensor proprius pol- licis; below the middle of the leg, it leaves the inter- osseous ligament, and passes gradually more forwards; it crosses under the tendon of the extensor proprius pollicis*, and is then situated between that tendon, and the first tendon of the extensor longus digitorum : at the ankle it runs over the fore-part of the tibia, being now situated more superficially; then over the astra- galus and os naviculare, and over the junction of the os cuneiforme internum and medium; crossing under that tendon of the extensor brevis digitorum which goes to the great toe.—Arriving at the space between the bases of the two first metatarsal bones, it plunges into the sole of the foot, and immediately joins the plan- tar arch. BRANCHES. 1. A. Recurrens, which ramifies over the fore- part of the knee, inosculating with the articular ar- teries. 2. Numerous twigs to the tibialis anticus, extensor pollicis, and other muscles on the fore-part of the leg. 3. A. Malleolaris Interna ramifies over the inner ankle, and inosculates with the perineal and pos- terior tibial arteries. 4. The External Malleolar ramifies over the outer ankle. * It is crossed by that tendon just above the lower head of the tibia, while under the annular ligament. 103 5. The Tarsal and Metatarsal Arteries are two small branches which cross the tarsal and me- tatarsal bones, and pass obliquely to the outer edge of the foot. From the tarsal or metatarsal artery come off the Interosseal Arteries, which supply the inleros- seal spaces, and the back-part of the toes. 6. A large branch comes off from the anterior ti- bial, where it is about to plunge into the sole of the foot; it runs along the space betwixt the two first metatarsal bones, and at the anterior extremity of those* bones, bifurcates into, (I.) A. Dorsalis Hallucis, a considerable branch which runs on the back-part of the great toe. (2.) A branch which runs on the inner edge of the toe next to the great one. 2. VEINS. The Anterior Tibial Vein consists of two branches, which accompany the artery and its rami- fications. 3. NERVES. The Anterior Tibial Nerve is a branch of the peroneal nerve ; it is seen in the ham arising from the peroneal, and crossing under the muscles on the out- side of the fibula:—It emerges from under the ex- tensor longus digitorum, comes in contact with the anterior tibial artery, and accompanies it down the leg; it is distributed on the back of the foot and toes. 104 SECT. II. DISSECTION OF THE POSTERIOR PART OF THE LEG. The fascia which invests the posterior part of the leg, is much thinner and less strong than in the fore- part ; it must be removed, to expose the parts now to be described. MUSCLES ON THE POSTERIOR PART OF THE LEG. These are seven in number. 1. The Gastrocnemius Externus, or Gemel- lus—Arises, by two distinct heads:—The first, or Internal Head, arises, tendinous, from the upper and back part of the internal condyle of the os femoris, and fleshy from the oblique ridge over that condyle.— The second, or External Head, arises, in the same manner, from the external condyle. Each of the heads forms a fleshy belly, the fibres of which are ob- lique, passing from a tendinous expansion which covers the posterior surface of the muscle, to another tendi- nous expansion which covers the anterior surface, or that surface which lies nearest the bones. The two bellies, of which the internal is by much the largest, are separated by a considerable triangular interval, in which the popliteal blood-vessels and nerves pass to the leg, but descending, unite a little below the knee-joint in a middle tendinous line, and below the middle of the tibia send off a broad flat tendon, which unites a little above the ankle with the tendon of the soleus. 105 Reflect the two heads of the gastrocnemius from the femoral condyles, and you will then expose, 2. The Soleus, or Gastrocnemius Internus— which arises, by two origins or heads. '\ he first, or External Origin, which is by much the largest, arises, principally fleshy, from the posterior surface of the head of the fibula, and from the external angle of that bone, for two-thirds of its length, immediately behind the peroneus longus. The second, or internal head, arises, fleshy, from an oblique ridge on the posterior surface of the tibia, just below the popliteus, and from the inner angle of that bone, during the middle third of its length. The two heads which are separated at first by the posterior tibial artery and nerve, unite immedi- ately, form a large belly, which, covered by the tendon of the gastrocnemius, is continued, fleshy, to within a short distance of the ankle-joint; a little above which the tendons of the gastrocnemius and soleus unite, and form a strong round tendon, named the Tendo Achil- lis, which slides over the upper and posterior part of the os calcis, where it is furnished with a small bursa mucosa, to be Inserted into a rough surface on the back-part of that bone. Situation: The gastrocnemius arises between the hamstring-tendons: Its belly is superficial, and forms the upper or greater calf of the leg; on lifting it up, the tendon is seen continued some way on its inner sur- face. The soleus has its largest part concealed by the gas- trocnemius, but part of it appears on each side of the belly of that muscle; and, at the lower part of the leg, 106 the belly is seen projecting through the tendon of the gastrocnemius, and forming the lower calf. Its fleshy belly is tendinous on its posterior surface, where the tendon of the gastrocnemius slides over it; and there is a bursa mucosa betwixt the upper part of the os calcis and the tendo Achillis. Use: To elevate the os calcis, and thereby to lift up the whole body, as a preparatory measure to its being carried forward in progression ;—to carry the leg back- wards on the foot when that is fixed ;—the gastrocne- mius, from its origin in the thigh, also bends the leg on the thigh. Synonyma: Gastrocnemius :—Bi-femoro-calca- nien. Soleus:—Tibio-peronei-calcanien. Both muscles are sometimes called Extensor Tarsi Suralis, vel Extensor Magnus. The heads of the gastrocnemius should now be lifted up, which will expose, 3. The Plantaris.—This muscle arises, fleshy, from the upper part of the external condyle, and from the oblique ridge above that condyle; forms a pyra- midal belly about three inches in length, which adheres to the capsule of the knee-joint, runs over the popliteus, and terminates in a long, slender, thin tendon. This tendon passes obliquely inwards over the inner head of the soleus, and under the gastrocnemius; emerges from between those two muscles, where their tendons unite, and then runs down by the inside of the tendo Achillis, to be Inserted into the posterior part of the os calcis, on 107 the inside of the insertion of the tendo Achillis, and somewhat before it. Situatio?i: The origin and belly of this muscle are concealed by the external head of the gastrocnemius; the lower part of the tendon is the only part that is su- perficial. Use: To extend the foot, and roll it inwards, and to assist in bending the leg. Synonyma: Tibialis gracilis ;—Extensor tarsi mi- nor ;—Petit-femoro-calcanien. 4. The Popliteus—Arises, within the capsular li- gament of the knee, by a round tendon, from a deep pit or hollow on the outer side of the external condyle ; adheres to the posterior and outer surface of the exter- nal semilunar cartilage; passes, within the cavity of the joint, over the side of the condyle to its back-part; perforates the capsular ligament, and forms a fleshy belly, which runs obliquely inwards, being covered by a thin tendinous fascia, to be Inserted, broad, thin, and fleshy, into an oblique ridge on the posterior surface of the tibia, a little be- low its head, and into the triangular space above that ridge. Situation: This muscle is concealed entirely by the gastrocnemius ; it lies above the inner head of the so- leus; it is more deeply situated than the plantaris, which crosses over it. Use: To bend the leg, and, when bent, to roll it, so a.s to turn the toes inwards. Synonyma: Femora-popliti-tibial. The belly of the soleus should now be lifted, in order to expose the deeply-seated muscles. A strong 108 membranous fascia is seen connecting and investing them, which is to be removed. This fascia also covers the posterior tibial vessels and nerve, but the descrip- tion of the course of these vessels, though seen in this stage of the dissection, must be deferred. The deep-seated muscles are, The Flexor Longus Digitorum Pedis, situated be- hind the tibia. The Flexor Longus Pollicis Pedis, situated behind the fibula. The Tibialis Posticus, which is almost concealed by the two other muscles, and by the fascia, which con- nects them, and binds them down. 5. The Flexor Longus Digitorum Pedis Per- forans—Arises, fleshy, from the posterior flat- tened surface of the tibia, between its internal and external angles, below the attachment of the soleus, and continues to arise from the bone to within two or three inches of the ankle; the fibres pass obliquely into a tendon which is situated on the posterior edge of the muscle. This tendon runs behind the inner ankle in a groove of the tibia, passes under a stong ligament which goes from the inner ankle to the os calcis, and, having Teceived a strong tendinous slip from the flexor pollicis longus, divides about the middle of the sole of the foot into four tendons, which pass through the slits in the tendons of the flexor digitorum brevis, and are Inserted into the extremity of the last joint of the four lesser toes. Situation: The belly of this muscle is concealed by the soleus, and lies on the inside of the flexor longus 109 pollicis. The situation of the tendon is described with the muscles situated in the sole of the foot. Use: To bend the last joint of the toes, and to assist in extending the foot. Synonyma: Flexor tertii internodii digitorum pedis; —Tibio-phalangettien-commun. 6. Flexor Longus Pollicis Pedis—Arises, fleshy, from the posterior flat surface of the fibula, con- tinuing its origin from some distance below the head of the bone to within an inch of the ankle. The fleshy fibres terminate in a tendon, which passes behind the inner ankle through a groove in the tibia; next through a groove in the astragalus, crosses in the sole of the foot the tendon of the flexor longus digitorum, to which it gives a slip of tendon; passes between the two sesa- moid bones, and is Inserted into the last joint of the great toe. Situation: The belly of this muscle is covered by the soleus; it lies on the outside of the flexor longus di- gitorum, between that muscle and the peroneus longus; the tendon, where it passes behind the inner ankle, is situated more backward than the tendon of the flexor digitorum longus, that is, nearer the os calcis, and will be seen in the foot. Use : To bend the last joint of the great toe, and, be- ing connected by a cross slip to the flexor digitorum communis, to assist in bending the other toes. Synonyma: Peroneo-phalanginien du gros orteil. 7 The Tibialis Posticus—Arisen, fleshy, from the posterior surface of both the tibia and fibula, imme- diately below the upper articulation of these bones with each other; from the whole of the interosseous liga- 110 nient; from the angles of the bones to which that liga- ment is attached ; and from the flat surface of the fibu- la behind its internal angle for more than two-thirds of its length. The fibres run obliquely towards a middle tendon, which, becoming round, passes behind the inner ankle through a groove in the tibia. Inserted into the upper and inner part of the os na- viculare, being further continued through a groove in that bone to the internal and external cuneiform bones; it also sends some tendinous filaments to the os calcis, the os cuboides, and the bases of .the metatarsal bones supporting the second and middle toe. Situation: This muscle may be said to arise from the tibia and fibula before the interosseous ligament, as its fibres fill up a perforation in the upper extremity of that ligament. The belly is concealed at its lower part by the flexor longus digitorum and flexor pollicis, and cannot be seen till those muscles are separated; but a part of it is discovered above the upper extremity of these muscles, and immediately below the fibres of the popliteus; and this part must lie under the anterior surface of the soleus. The tendon crosses under that of the flexor longus digitorum above the ankle, and, where it passes through the groove in the tibia, is situ- ated more forward than the tendon of that muscle. It is thickened where it runs through the groove of the os naviculare; and its insertion lies close in contact with die bones, and is concealed by the muscles in the sole of the foot. Use: To extend the foot, and turn it inwards. Synonyma: Tibio-tarsien. Ill VESSELS AND NERVES OF THE POSTERIOR PART OF THE LEG. 1. ARTERIES. Arteria Tibialis Postica.—The posterior tibial artery, which is the continued trunk of the popliteal, sinks under the origins of the soleus, and runs down the leg between that muscle and the more deeply scat- tered flexors of the toes: It does not lie in immediate contact with the fibres of the flexors, but, like the fe- moral artery, is invested by a strong sheath of con- densed cellular membrane. It is, together with its veins and accompanying nerve, also supported by the fascia which binds down the deep-seated muscles. As it descends, it gradually advances more forwards, fol- lowing the course of the flexor tendons: it passes be- hind the inner ankle, in the sinuosity of the os calcis, lying posterior to the tendon of the flexor longus digitorum, and anterior to that of the flexor longus pollicis. Here it is close upon the bone, and its pul- sation may be felt. It sinks under the abductor pol- licis, arising from the os calcis, and immediately di- vides into two branches: (1.) The Internal Plantar Artery is the smallest, and ramifies among the mass of muscles situated on the inner edge of the sole of the foot. (2.) The External Plantar Artery directs its course outwards, and having reached the metatarsal bone of the little toe, forms the Plantar Arch, which crosses the three middle metatarsal bones obliquely, about their middle, and terminates at the space be- twixt the two first metatarsal bones, where the trunk 112 of the anterior tibial artery joins the arch. The con- vexity of this arch is towards the toes, and sends off the following branches. a, A small branch to the outside of the little toe. b, Ramus digitalis primus, or the first digital arte- ry, which runs along the space between the two last metatarsal bones, and bifurcates into two branches, one to the inner side of the little toe, and the other to the outer side of the next toe. r, The second digital artery, which runs along the next interosseous space, and bifurcates in a similar manner. d, The third digital artery. e, The fourth, or great digital artery, which supplies the great toe, and the inner side of the toe next to it. The concavity of the arch sends off the interosseal arteries, three or four small twigs, which go to the deep- seated parts in the sole of the foot, and, perforating between the metatarsal bones, inosculate with the supe- rior interosseal arteries on the upper side of the foot. The branches of the Posterior Tibial Artery in the leg are, 1. The Peroneal Artery, which comes off from the tibial a little after it has sent off the anterior tibial, of which this artery is sometimes a branch ; it is generally of a considerable size, sometimes nearly as large as the tibial itself; it runs upon the inside of the fibula, giving numerous branches to the peroneal muscles and flexor of the great toe ; but its course is irregular and inconstant. At the lower part of the leg, it splits into, o, A. Peronea Anterior, which passes betwixt 113 the lower heads of the tibia and fibula, to the fore-part of the ankle, where it is lost. b, A. Peronea Posterior is properly the termi- nation of the artery ; it descends along the sinuosity of the os calcis, inosculating with the branches of the tibialis postica, and terminates in the posterior part of the sole of the foot. 2. Muscular branches arise from the artery as it de- scends ; twigs also are se'ht over the heel and ankle. 2. VEINS. Ven;e Tibiales Pos.tic^e.—The posterior tibial veins are generally two in number; they accompany the artery, and terminate in the popliteal vein ; they are formed of branches, which correspond to those of the artery. 3. NERVES. The Posterior Tibial Nerve, which is the con- tinuation of the great sciatic nerve, sinks below the so- leus, and accompanies the posterior tibial artery; it gives off numerous filaments to the muscles in its neighbourhood. At first it continues, as in the ham, immediately behind the artery, but it gradually gets on the outside of it as it descends ; so that where they pass along the sinuosity of the os calcis, the nerve is si- tuated close in contact with the side of the artery, but nearer to the projection of the heel than that vessel is. With the artery, it divides into, I. The internal plantar nerve, and, 2. The external plantar nerve.—These nerves sup- ply the muscles and integuments in the sole of the foot. k 2 114 SECT. III. DISSECTION OF THE SOLE OF THE FOOT. The cuticle is very much thickened on the sole of the foot from constant pressure; betwixt the integu- ments and plantar aponeurosis, we find a tough granu- lated fat, which adheres firmly to the aponeurosis, and is dissected off with difficulty. Aponeurosis, seu Fascia Plantaris, is a very strong, tendinous expansion, which arises from the projecting extremity of the os calcis, and passes to the root of the toes, covering and supporting the muscles of the sole of the foot. Where it arises from the heel, it is thick, but narrow; as it runs over the foot, it be- comes broader and thinner; and it is fixed to the head of each of the metatarsal bones by a bifurcated extre- mity, which, by its splitting, leaves room for the ten- dons, Sec to pass. It seems divided into three por- tions, which are connected by strong fasciculi of tendi- nous fibres ; and fibres are sent down, forming perpen- dicular partitions among the muscles, and separating them into three classes: I. The middle portion, which is the largest, and under which are contained the flexor brevis digitorum, and the tendons of the flexor longus and lumbrica- les. 2. The external lateral portion, which covers the muscles of the little toe. 3. The internal lateral portion, concealing the mus- cles of the great toe. On removing the plantar aponeurosis, the first 115 order of muscles in the sole of the foot is exposed: it consists of three muscles: Abductor Pollicis, situated on the side of the great toe. Abductor Minimi Digiti, on the side of the little toe. Flexor Brevis Digitorum Pedis, the mass in the mid- dle, situated between the two abductors. 1. Abductor Pollicis Pedis--Arises, tendinous and fleshy, from the lower and inner part of the os cal- cis ; from a ligament which extends from the os calcis to the os naviculare; from the inside of the os navicu- lare and cuneiforme internum; and from the fascia plantaris. Inserted, tendinous, into the internal sesamoid bone, and base of the first phalanx of the great toe. Use: To move the great toe from the rest. Synonyma: Thenar-calcaneo-phalangien du pouce. 2. Abductor Minimi Digiti Pedis—Arises, ten- dinous and fleshy, from the outer side of the os cal- cis ; and from a strong ligament, which passes from the os calcis to the metatarsal bone of the little toe; al- so from the fascia plantaris. Inserted, tendinous, into the base of the metatarsal bone of the little toe, and into the outside of the base of the first phalanx. This muscle can frequently be divided distinctly into two portions. Use: To move the little toe from the other toes. Synonyma: Parathenar major, and metatarseus ;— Calcaneo-pbalangien du petit doigt. 3. Flexor Brevis Digitorum Pedis Perfora- 116 tub—Arises, fleshy, from the anterior and inferior part of the protuberance of the os calcis, and from the inner surface of the fascia plantaris; also from the tendinous partitions betwixt it and the abductors of the great and little toe:—it forms a thick fleshy belly, and sends off four tendons, which split for the passage of the tendons of the flexor longus digitorum, and are Inserted into the second phalanx of the four lesser toes. The tendon of the little toe is often wanting. Use: To bend the second joint of the toes. Synonyma: Calcaneo phalanginien commun. Situation: The muscles of this order are quite su- perficial, being only covered by the fascia plantaris. The first order of muscles being removed, or being lifted from their origins, and left hanging by their ten- dons, the second order is exposed. 1. The tendon of the Flexor longus digitorum pedis is seen coming from the inside of the os calcis ; and, having reached the middle of the foot, dividing into its four tendons, which pass through the slits of the tendons of the flexor digitorum brevis, and are insert- ed into the base of the last phalanx of the four lesser toes. 2. The tendon of the Flexor longus pollicis is seen crossing under* the tendon of the flexor longus digi- torum, and, having given to it a short slip of tendon, * In the erect posture, it crosses above, lying nearer to the me- tatarsal bones than that tendon; but in the description, the sole •f the foot is supposed to be placed uppermost. 117 proceeding between the two sesamoid bones to the base of the last phalanx of the great toe. 3. Flexor Digitorum Accessorius, or Massa Carnea Jacohi Sylvii—Arises, fleshy, from the sinu- osity at the inside of the os calcis, and, tendinous, from that bone more outwardly:—it forms a belly of a square form. Inserted into the outside of the tendonof the flexor digitorum longus, just at its division. Use: To assist the flexor longus. 4. Lumbricales Pedis—Arise, by four tendinous and fleshy beginnings, from the tendons of the flexor longus digitorum, immediately after their division. Inserted, by four slender tendons, into the inside of the first phalanx of the four lesser toes, and into the tendinous expansion that is sent from the extensors to cover the upper part of the toes. Use: To promote the flexion of the toes, and to draw them inwards. Situation: The muscles of the second order are co- vered and concealed by those of the first order; but the insertion of their tendinous extremities may be seen on removing the integuments. The second order of muscles being removed, we ex- pose the third order, 1. Flexor Brevis Pollicis Pedis.—It arises, tendinous, from the under and fore-part of the os calcis, where it joins wjth the os cuboides; also from the os cuneiforme externum; it forms a fleshy belly, which is connected inseparably to the abductor and adductor pol- licis. Inserted, by two tendons, into the external and in- 118 ternal sesamoid bones; and it is continued on into the base of the first phalanx of the great toe. Use : To bend the first joint of the great toe. Synonyma: Tarso-phalangien du pouce. 2. Adductor Pollicis Pedis—Arises, tendinous and fleshy, from a strong ligament which extends from the os calcis to the os cuboides, and from the roots of the second, third, and fourth metatarsal bones; it forms a fleshy belly, which seems at its beginning divided in- to two portions. Inserted, tendinous, into the external sesamoid bone, and root of the metatarsal bone of the great toe. Use: To bring this toe nearer the rest. Synonyma: Antithenar-tarso-metatarso-phalangien du pouce. 3. Flexor Brevis Minimi Digiti Pedis—Arises, tendinous and fleshy, from the os cuboides, and from the root of the metatarsal bone of the little toe. Inserted, tendinous, into the base of the first phalanx of the little toe, and into the anterior extremity of the metatarsal bone. Use: To bend this toe. Synonyma; Parathenar minor;—Flexor primi inter- nodii minimi digiti;—Metatarso-phalangien du petit doigt. 4. Transversalis Pedis—Arises, tendinous, from the anterior extremity of the metatarsal bone support- ing the little toe; becoming fleshy, it crosses over the anterior extremities of the other metatarsal bones. Inserted, tendinous, into the anterior extremity of the metatarsal bone of the great toe, and into the in- 119 < ternal sesamoid bone, adhering to the adductor pol- licis. Use: To contract the foot, by bringing the toes near- er each other. Synonyma : Metatarso-phalangien du pouce. Ranging with this order of muscles, we may also ob- serve A broad, strong ligament, passing from the anterior sinuosity of the os calcis over the surface of the os cu- boides. The tendon of the tibialis posticus, dividing into nu- merous tendinous slips, to be inserted into the bones of the tarsus. Situation: The muscles of the third order lie under those of the second order, but are only partially con- cealed:—The flexor brevis pollicis lies under the ten- don of the flexor longus pollicis; the adductor pollicis lies on the outer side of the flexor brevis, and is in part concealed by the tendons of the flexor digitorum longus. __The flexor brevis minimi digiti is a small fleshy mass, lying on the metatarsal bone of the little toe, and not concealed by any muscle of the second order.—The transversalis pedis runs across under the tendons of the flexor digitorum longus and lumbricales, and is seen projecting betwixt those tendons. Having removed the muscles last described, we ex- pose the fourth and last order. The tendon of the peroneus longus is seen passing along a groove in the os cuboides, and crossing the tar- sal bones, to be inserted into the base of the metatarsal bone of the great toe, and into the internal cuneiform and second metatarsal bones. 120 Interossei Pedis Interni, are three in number, situated in the sole of the foot—They arise, tendinous and fleshy, from between the metatarsal bones of the four lesser toes, and are Inserted, tendinous, into the inside of the base of the first phalanx of each of the three lesser toes. Use: To move the three lesser toes inwards towards the great toe. Synonyma: Interossei inferiores;—Abductor medii digiti, abductor tertii, and minimi digiti pedis;—Sous metatarso-lateri-phalangiens. Interossei Pedis Externi, are four in number, larger than the internal interossei, and situated on the back of the foot; they are bicipites, or arise by two slips. Arise, tendinous and fleshy, between the metatarsal bones of all the toes. Inserted, the first, abductor indicis pedis, into the in- side of the base of the first phalanx of the fore-toe;— the second, adductor indicis pedis, into the outside of the same tOe;—the third, adductor medii digiti pedis, into the outside of the middle toe;—the fourth, adduc- tor tertii digiti pedis, into the outside of the third toe. Use: To separate the toes. Synonyma: Sus-metatarso-lateri phalangiens. 121 CHAP. VI. DISSECTION OF THE HEAD. SECT. I. OF THE EXTERNAL PARTS OF THE HEAD. THE integuments of the head are thick, and covered with hair; under the cutis there is a cellular substance, which is much condensed, and closely connected with the epicranium, or expanded tendon of the occipito-fron- talis. This connection renders the dissection of that muscle difficult. The Occipito-frontalis is the only muscle which properly belongs to the hairy scalp; it is a single broad digastric muscle, Arising, on each side of the head, fleshy and tendi- nous, from the transverse ridge of the occipital bone, as far forward as the mastoid process;—it forms a broad thin tendon, which covers the whole upper part of the cranium. Inserted, fleshy, on each side, into the orbicularis palpebrarum, skin of the eye-brows, and the internal angular process of the os frontis and os nasi. L 122 C- Situation: The tendon adheres firmly by cellular membrane to the skin, but very loosely to the pericra- nium, or periosteum of the cranium. At its insertion it intermixes with the muscles of the upper part of the face. Use : To pull the skin of the head backwards, raise the eye-brows, and corrugate the skin of the fore- head. Synonyma: Epicranius;—Frontalis et occipitalis. The muscles of the ear are of three classes. 1. The common muscles move the external ear; they are not always so distinct as to admit of a clear demon- stration. (1.) Attollens Aurem—Arises from the tendon of the occipko-frontalis, and from the aponeurosis of the temporal muscle. Inserted into the upper part of the root of the carti- lage of the ear, opposite to the antiheiix. Use: To draw the ear upwards. Synonyma : Attollens auricula ;—Superior auris ;— Temporo-conchinien. (2.) Anterior Auris—Arises, thin and mem- branous, from the posterior part of the zygomatic'pro- cess of the temporal bone. Inserted into a small eminence on the back of the helix, opposite to the concha. Use : To draw the eminence a little forwards and up- wards. Synonyma: Anterior auricula;—Zygomato-conchi- nien. (3.) The Retrahentes Auris—Arise, by two or three distinct slips, from the external and posterior 123 part of the mastoid process, immediately above the in- sertion of the sterno-cleido mastoideus. Inserted into that back-part of the ear which is opposite to the septum, dividing the scapha and con- cha. Use: To draw the ear back, and stretch the con- cha. Synonyma: Deprimens auricula;—Posterior auris ; —Mastoido-conchinien. 2. The proper muscles of the ear must be here de- scribed, but the student must not expect to meet with them distinctly marked in every subject; in general they are very confused and indistinct. (1.) Helicis Major—Arises from the upper and acute part of the helix, anteriorly. Inserted into its cartilage, a little above the tragus. Use: To depress the part from which it arises. Synonyma: Helix. (2.) Helicis Minor—Arises from the inferior and anterior part of the helix. - Inserted into the crus of the helix, near the fissure in the cartilage opposite to the concha. Use : To contract the fissure. J Synonyma: Concho-helix. (3.) Tragicus—Arises from the middle and outer part of the concha, at the root of the tragus, along which it runs. Inserted into the point of the tragus. Use: To pull the point of the tragus a little for- wards. Synonyma: Concho-tragique. '4.) Antitragicvs—Arises from the internal part 124 of the cartilage that supports the antitragus ; and, run- ning upwards, is Inserted into the tip of the antitragus as far as the inferior part of the antihelix. Use: To turn the tip of the antitragus a little out- wards, and depress the extremity of the] antihelix to- wards it. Synonyma: Anthela-tragique. (5.) Transversus Auris—Arises from the pro- minent part of the concha on the dorsum of the ear. Inserted opposite to the outer side of the antihelix. Use: It draws the parts to which it is connected to- wards each other, and stretches the scapha and con- cha. Synonyma: Concho anthelix. 3. The muscles of the internal ear are situated within the temporal bone itself; they are very small, and can only be seen when the internal parts of the or- gan of hearing are prepared; but, in order to render the history of the muscles complete, I shall insert a description of them. (1.) Lax a tor Tympani—Arises, by a small be- ginning, from the spinous process of the sphenoid bone, and side of the Eustachian tube. It runs back- wards, and a little upwards, along with the nerve called Chorda Tympani, in a fissure of the glenoid or articu- lar cavity of the os temporis. Inserted into the long process of the malleus. Use: To draw the malleus obliquely forwards to- wards its origin, and consequently the membrana tym- pani by which that membrane is made less concave, or is relaxed. 125 Synonyma: Externus mallei;—Obliquus auris;— Anterior mallei;—Spheni-salpingo-mallecii. (2.) Tensor Tympani—Arises, by a small fleshy beginning, from the cartilaginous extremity of the Eus- tachian tube, just where it begins to be covered by the pars petrosa and spinous process of the sphenoid bone, and runs along the bony half-canal of the typanum, where if is invested by a membranous vagina. Inserted into the neck of the malleus, above the small process, advancing likewise as far as the handle. Use: To pull the malleus and membrana tympani towards the pars petrosa, by which that membrane is made more concave and tense. Synonyma: Internus auris ;—Internus mallei;—Sal- pingo-malleen. A third muscle has by some been described, under the name of External or Superior Muscle of the malleus; but this is much less distinct. It is de- scribed as Arising from the internal, superior, and posterior part of the meatus externus, to be fixed by a small tendon to the neck of the malleus. Synonyma: Acoustico-malleen. 3. Stapedius is a short and thick muscle.—It arises from, and lies concealed within, the small bony pyra- mid at the bottom of the tympanum ; the cavity it fills is near the bony canal of the portio dura of the auditory nerve. It terminates in a small tendon, which goes out of the cavity through the small hole in the apex of the pyramid, runs forwards, and is Inserted into the neck of the stapes, on the sides of the longest and most crooked leg of that bone. l2 126 Use: To draw the stapes obliquely upwards to- wards the pyramid, by which the posterior part of its base is moved inwards, and the anterior part out- wards. Synonijma: Musculus stapedis;—Pyramidal stape- dien. SECT. II. 6f the contents of the cranium, OR THE BRAIN AND ITS MEMBRANES. A transverse incision, extending from ear to ear over the crown of the head, being made through the tendon of the occipito-frontalis, the two flaps may, with facility, be inverted on the face and neck. Remove the superior part of the cranium by a saw directed anteriorly through the frontal bone above the orbitar process, and posteriorly as low as the trans- verse ridge of the occipital bone. Thus the subsequent demonstration of the brain will be conducted with greater facility. When the superior part of the cranium, commonly called the Calvarium, or skull-cap, is torn off, which requires considerable force, you expose the Dura Mater, a firm, compact, and whitish membrane, somewhat shining, rough on its outer surface, from the rupture of vessels which connected it to the cra- nium, and covered with bloody spots in consequence of the blood effused from these ruptured orifices. It 127 is described as being separable into many lamina, into two with facility ; and it is said that these two lamina, by separating and re-uniting, form the triangular cavi- ties, named Sinuses, which are in fact large veins. This division of layers can hardly be admitted as cor- rect in the recent state of the membrane. The Superior Longitudinal Sinus lies in a groove formed by the two parietal bones; it extends along the sagittal suture from the crista galli of the ethmoid bone to the middle of the os occipitis, where it bifurcates into the two lateral sinuses; in its pas- sage backwards, its size is increased. When slit open, its triangular form is evident; it is lined by a smooth membrane, and in it may be remarked the numerous openings of the veins of the pia mater, the frena, or slips of fibres crossing from side to side, glandula Pacchioni interna et externa, little bodies like millet-seed seen on the outer and inner surface of the sinus. The arteries of the dura mater are divided into the anterior, middle, and posterior. 1. Arteria Meningea Media (called also the Spinalis or Spheno-spinalis), the great middle ar- tery, is a branch of the internal maxillary; it passes through the spinous hole of the sphenoid bone, and is seen rising from the anterior inferior angle of the parietal bone (in a groove of which it lies), and spread- ing its numerous branches over the dura mater. The anterior and posterior arteries are small. 2. A. Meningea Anterior is sent off from the 128 external carotid, and enters the cranium by the fora- men lacerum orbitale superius. 3. A. Meningea Posterior is given off by the veitebral artery; the dura mater also receives small twigs from the occipital, pharyngeal arteries, &c. The nerves of the dura mater are said to come from the fifth pair; if they exist at all, they are small, and seldom demonstrated. of the septa of the brain, or processes of the dura mater. I. The Falx (septum sagittale, verticale, mediasti- num cerebri, or falciform process) is a long and broad fold, or duplicature of the inner lamina of the dura mater, dividing the cerebrum into two hemispheres, extending from the crista galli of the ethmoid bone, along the middle of the os frontis and point of junction of the two parietal bones, to the crucial ridge of the oc- cipital bone, where it terminates in the middle of the next septum. 2. The Tentorium Cerebelli, or transverse septum. This separates the cerebrum from the cere- bellum, and is formed by the inner lamina of the dura mater, reflected off from the os occipitis along the groove of the lateral sinuses, and the edge or angle of the temporal bones. It is frequently called Ten- torium Cerebello Super Extensum. Its position is ho- rizontal. There are some other folds of the dura mater, not visible in this stage of the dissection. 129 3. The falx of the cerebellum, or small occipital septum, will be seen when the cerebrum is removed. It extends from the middle of the tentorium along the middle spine of the os occipitis to the foramen mag- num, dividing the cerebellum into two parts. 4. The sphenoidal folds, two small folds of the dura mater, one on each side of the sella turcica, stretching from the posterior to the anterior clinoid processes. The dura mater also, in many parts of the brain, separates its lamina to form sinuses; the principal of these will be noticed in the course of the dissection. This membrane should now be divided in the line of the division of the cranium; its internal surface is smooth, glistening, and free from adhesion, except in the course of the longitudinal sinus, into which veins pass from the pia mater. Detach the falx from the crista* galli, and turn it backwards; observe in its lower edge the Infe- rior Longitudinal Sinus, which enters a sinus in the Tentorium,' termed Torcular Herophili, or straight sinus. This will fully expose the convolu- tions of the brain, which are closely invested by the pia mater. The Pia Mater consists of two membranes. 1. The Tunica Arachnoides is a fine mem- brane, covering uniformly the surface of the pia mater, without passing into the interstices of its duplicatures. It is attached to it, is extremely thin, transparent, without vessels, demonstrated with difficulty on the upper surface of the brain by the blow-pipe (which 130 raises it into cells), but on the base of the brain it can be distinctly seen. 2. The proper Pia Mater, or tunica vasculosa, is a very vascular membrane, transparent in the interstices of its vessels, investing the substance of the brain, de- scending betwixt all its convolutions, and lining its different cavities; but, where it lines the ventricles, it is fine, delicate, and less vascular, than on the surface, and betwixt the convolutions of the brain: It is con- nected to the dura mater by its veins passing into the longitudinal sinus. The brain is divided into three parts: 1. The ce- rebrum; 2. The cerebellum; 3. The medulla oblon- gata. The Cerebrum consists of two distinct sub- stances : 1. The cineritious or cortical substance forming the outer part. ^ 2. The white*r medullary substance forming the inner part. The brain is divided by the falx into two hemi- spheres, and by the pia mater into numerous convolu- tions. Pjl Each hemisphere is divided into three lobes. 1. The Anterior Lobes rest on that part of the cranium which forms the two orbits, and is called the anterior fossa of the basis of the cranium. 2. The Middle Lobes are situated before and above the medulla oblongata, and rest on the middle fossa of the basis cranii, which are formed by the sphe- noid and temporal bones. 131 3. The Posterior Lobes are supported by the tentorium. The anterior and middle lobes are parted by a deep narrow sulcus, which ascends obliquely backwards from the temporal ala of the os sphenoides to near the middle of the os parietale; it is termed Fissura Cerebri, or Fissura Magna Silvii. By gently separating with the fingers the two he- mispheres of the brain*, we see passing betwixt them a longitudinal white convex body, the Corpus Cal- losum ; it lies under the falx, incurvates downwards at both its extremities, and is continued anteriorly into the medullary substance betwixt the corpora striata, posteriorly into the fornix and inferior cornu of the lateral ventricle on each side. On the surface of the corpus callosum is seen the Raphe, formed by two longitudinal medullary lines united by transverse fibres. When the brain is cut horizontally on the level of the corpus callosum, an appearance is produced, termed the Medullary arch, or Centrum Ovale. Under this arch are the two lateral venlriclest. H one of these be cautiously perforated on the side of the corpus callosum, and gently inflated by a blow-pipe, its extent may be seen ; but, if much force be used, the air will pass into the other ventricle. * Between the hemispheres and on the surface of the corpus callosum, we observe the arteris calloss, which are the conunua- tion of the tnmks of the anterior cerebri. .,,,,. + To show the lateral ventricles, the corpus callosum should be cut away close to the septum lucidum, and then the ventnele of thL body, andthethicknessandbreadthof the septum nself, wHl be more clearly seen. 132 The two ventricles are separated by a medullary par- tition, which descends from the inferior surface of the corpus callosum to the fornix, the Septum Lucidum ; it consists of two lamina, with a narrow cavity be- tween. To see this septum, one of the ventricles must be laid open, and the septum pulled gently to the other side. The Lateral Ventricles are two, right and left, lined with a fine membrane, narrow, consisting of a body, and three prolongations or cornua. 1. The body is formed betwixt the corpus callosum, the medulla of the brain, the convexity of the corpus striatum, and the thalamus nervi optici. 2. The anterior cornu or horn is formed betwixt the more acute convexity of the corpus striatum, and the anterior part of the corpus callosum. 3. The posterior cornu (called also the digital cavity) may be traced stretching backwards and downwards in- to the posterior lobe of the brain. 4. The inferior or descending cornu cannot be tra- ced in this stage of the dissection; it seems like the continued cavity of the ventricle, takes a curve back- wards and outwards, and then, turning forwards, de- scends into the middle lobe of the brain. The lateral ventricles communicate with each other, and with the third ventricle, by an opening under the fore-part of the arch of the fornix*. * It has been doubted whether or not this be an opening; the choroid plexus passes through it, and seems to unite the surfaces; it is absurdly named the Foramen Monroianum, from a mistaken notion that Dr. Monro discovered it, and may be seen by gently turning the anterior crus of the fornix to one 133 In the lateral ventricles we meet with The Fornix, a medullary body, flat, and of a triangular shape, which divides the two lateral and the third ventricles. It is exposed on tearing away the septum lucidum; its lower surface is towards the third ventricle; its lateral margins are in the lateral ventricles; on its upper surface it supports the sep- tum lucidum, and under its most anterior part is the foramen Monroianum:—One of the angles of this body is forward, and the other two towards the back- part ; it rests chiefly on the thalami nervorum opti- corum, but is separated from them by a vascular membrane called the velum. The extremities of the body of the fornix are named its Crura. 1. The crus anterius is double, bends downwards before the anterior commissure of the brain, with which it is connected, and may be traced into the corpora caudicautia. 2. The two crura posteriora, coalescing with the back-part of the corpus callosum, pass, on each side, into the inferior cornu of the lateral ventricle, and terminate in a pointed form on the hippocampus major. Divide the body of the fornix, invert it, by turning side; it is a space betwixt the most anterior part of the con- vexity of the thalami nervorum opticorum, and the anterior crus of the fornix. This foramen may always be easily found by following the course of the plexus choroides, as it passes forwards in the ventricle. It is a slit, rather than a round hole, in the natural state. M 134 the anterior crus forwards, and the posterior crura backwards ; on the under surface of the latter is an ap- pearance of transverse lines, named Corpus Psalloides, psalterium, or lyra. The inversion of the fornix exposes The Plexus Choroides.—This is a continuation of the pia mater, a spongy mass, consisting of folds of tortuous vessels, partly covering the thalami nervorum opticorum, and continued into the inferior cornu of the lateral ventricles. The plexus of each side is connected to its fellow by the velum interpositum. a membrane which passes under the fornix, and lies on the third ventricle and corpora quadrigemina. From this plexus the blood is received by the Vena Galeni, situated in the middle of the velum which consists of two parallel branches; these run backwards, unite, and enter the fourth sinus of the dura mater, called Torcular Herophili. This plexus should now be detached at its fore- part, and turned back: it will remain as a guide to the knife in tracing the inferior cornu of the lateral ventricle. We now see The Corpora Striata, two smooth cineritious convexities, in the fore-part of the lateral ventricle, broad, and rounded anteriorly, becoming narrow, and diverging as they pass backwards, consisting of me- dullary and cortical substance disposed in stria. The Thalami Nervorum Opticorum, two large oval whitish eminences, placed by the side of each other between the diverging extremities or crura of the corpora striata; towards their fore-part is a 135 peculiar eminence or convexity, called the Anterior Tu- bercle ; they are elongated downwards, to form the op- tic nerves. T^nia Semicircularis, a white medullary line, running in the angle betwixt the corpus striatum and thalamus nervi optici of each side. Commissura Anterior Cerebri, a short cylin- drical medullary cord, stretched transversely between the fore and lower part of the corpora striata, imme- diately under the anterior crura of the fornix. Just above the commissura anterior, and before the thalami, is the Vulva, or foramen commune anterius, a small slit or indentation, formed by the anterior crus of the fornix, bifurcating, and inserting itself, on each side, between the corpus striatum and thalamus nervi optici. This slit is the space by which the three ven- tricles communicate. Commissura Mollis is an exceedingly soft, broad, cineritious junction betwixt the convex surfaces of the thalami nervorum opticorum. On separating the optic thalami, we discover the Third Ventricle.—This is a longitudinal sulcus, or slit, situated betwixt the thalami nervorum opti- corum, and betwixt the crura cerebri. Above, it is covered by the fornix and velum interpositum; at its upper and fore-part, it communicates with the two la- teral ventricles; below the commissura anterior, it opens into the infundibulum. This opening is termed iter ad infundibulum. Backwards, it is continued by a canal which passes under the tubercula quadrigemina into the fourth ventricle.—This passage is named iter 136 ad quartum ventriculum, aquaductus Sylvii, or canalis medius. Anus, or foramen commune posterius, is situated behind the commissure of the optic thalami, and before the corpora quadragemina. It is closed up by the ve- lum interpositum, and, when that is removed, leads into the back-part of the third ventricle. The Pineal Gland, a small, soft, greyish, and conical body, of the size of a pea, is seated above the tubercula quadrigemina, and behind the thalami, to which it is connected by two white pedunculi, or foot-stalks; its base is turned forwards, and the apex backwards; it is covered by the plexus choroides and posterior crura of the fornix. It contains an earthy matter, either in its own substance, or that of the pedunculi, resembling sand, and, when viewed by a magnifier, assuming a granulated and clear light yellow appearance. It was named by Scemmerring, who first discovered that it belongs to the healthy structure of the brain, the Acervulus Glandulje PlNEALIS. Commissura Posterior, a transverse cord at the back-part of the third ventricle, before the tubercula quadrigemina, and above the iter ad quartum ventri- culum. Tubercula Quadrigemina, four small white bo- dies, adhering together, lying under the pineal gland, behind the third ventricle, and above the fourth. The uppermost two are named Nates, and the other two Testes. From the under part of the testes, there projects backwards, connecting itself with the crura cerebelli, 157 a thin medullary lamina, which is the valvula Vieus- senii, processus a cerebello ad testes, velum interjec- tum, valvula major. The inferior cornu of the lateral ventricle, which descends into the middle lobe of the brain, may now be traced, by following.the tract of the choroid plexus*; in it is seen The Hippocampus Major, or Cornu Ammonis. At its commencement it is narrow, but it becomes a broad medullary projection of the floor of the ventricle, and its extremity, which is called Pes Hippocampi, is curved inwards. The thin edge on its inside, which follows the whole of its circuit, is named the Corpus Fimuriatum, or Tania Hippocampi. The posterior crus of the fornix runs along its inner and anterior part, in the form of a thin floating edge. In the posterior cornu of the lateral ventricle, which passes into the posterior lobe of the brain, there is a si- milar medullary projection, but smaller, the Hippo- campus Minor. In the anterior part of the third ventricle, below the iter ad infundibulum, are seen the Corpora Albi- cantia Willisii (corpora mamillaria or subrotunda), two medullary eminences of the size of peas ; the re- mainder of these bodies is seen on the outer surface of the base of the brain. This completes the demonstration of the cerebrum. The whole of the posterior lobes, and the lateral part of the middle lobes, may be removed. This exposes to your view * Or it may be exhibited by cutting away successive slices of the side of the brain, until the ventricle is exposed. M 2 138 The Tentorium, and the Falx Cerebelli. At this point you should trace the bifurcation of the longitudinal sinus into the two lateral sinuses. The lateral sinuses are formed by the splitting of the lami- na of the tentorium; hence they follow the course of that membrane, run along their grooves in the occipi- tal bone, and dip downwards and forwards through the foramen lacerum in basi cranii, to terminate in the in- ternal jugular veins. The Torcular Herophili, or fourth sinus, runs along the middle of the tentorium, and joins the extre- mity of the longitudinal sinus at the point where it bi- furcates. The great notch of the tentorium is a circular opening left on the anterior part of the tentorium, allowing a junction between the cerebrum and cere- bellum. Now proceed to the examination of the cerebellum ; and, in order to accomplish this demonstration, it will be convenient to remove the posterior part of the os oc- cipitis. Cerebellum.—This part of the brain, divided into ' two lobes by the falx cerebelli, or septum occipitale, is eovered by a vascular membrane ; consists of medullary and cineritious substance; but, instead of convolutions, has numerous deep sulci, into which the pia mater dips, and forms thin flat strata. Remark the following processes. 1. Appendix, vel processus vermiformis superior, si- tuated under the pia mater, on the anterior and supe- rior part of the cerebellum. 2. Appendix, or processus vermiformis posterior, 139 will be found situated between the two lobes on the under surface of the cerebellum, and immediately be- hind the medulla oblongata. On separating the two lobes behind, and making a deep incision, we discover The Fourth Ventricle.—The sides of this ventricle are formed by the cerebellum, the anterior part by the medulla oblongata, the upper and back part by the valvula cerebri; it is lined by a thin vascular membrane, and has on its fore part a groove or fissure, which, terminating in a sharp point, is named Calamus Scriptorius. On each side of this groove are seen several medullary lines, which are the origin of the portio mollis of the seventh pair of nerves. The iter a tertio ad quartum ventriculum enters the upper part of the fourth ventricle. The valvula cerebri hangs over it. On cutting the cerebellum perpendicularly, there is formed, from the intermixture of cineritious and medullary matter, a tree-like appearance, named Arbor Vn &, of which the trunk is termed the peduncle of the cerebellum, and is continued to the back-part of the medulla oblongata. This concludes the demonstration of the cerebellum. To demonstrate the medulla oblongata and nerves, either the brain must be removed from the cranium, or it may be gradually inverted in the progress of the demonstration ;—and this is the better method. The inversion must be begun at the fore-part, by raising the anterior lobes of the cerebrum. Thus you will see, 1. The First Pair of Nerves, the Olfactory, called also Processus Mammillares. They arise from 140 the outside of the corpora striata, between the ante- rior and middle lobe of the brain; run under the anterior lobes, being lodged on two superficial grooves, and lying between the pia and dura mater; expand into a small oval ganglion, from which several small filaments descend through the cribriform plate of the ethmoid bone, to ramify on the membrane lining the nose. 2. The Second Pair, the Optic, arise from the posterior part of the optic thalami, and also from the tubercula quadrigemina; they make a circle round the crura cerebri called the Tractus Opticus. The two nerves • approach gradually, and unite, just before the pituitary gland, on the fore-part of the sella Tur- cica. They then diverge, and each nerve passes «out at the foramen opticum of the sphenoid bone, to form the retina of the eye. On each side of these nerves are seen the Carotid Arteries. Each artery emerges from the cavernous sinus by the side of the anterior clinoid process: sends a branch forwards, which, uniting with a similar branch of the other carotid, forms the anterior part of the Circulus Arteriosus Willisii; while other branches, passing backwards, and uniting with branches of the basilar artery, complete the posterior part of the arterial circle. A fold of dura mater passes from the anterior to the posterior clinoid process of each side. This fold is double, and forms by its duplicature the Cavernous Sinus. On dividing the optic nerves, and inverting them, we see the infundibulum, a funnel of cineritious sub- 141 stance, leading from the inferior and anterior extre- mity of the third ventricle to the pituitary gland ; it is generally imperforate before it reaches the gland. The Pituitary Gland, a reddish body, somewhat globular, consisting of two lobes, is situated in the sella Turcica of the sphenoid bone, partly covered by a fold of dura mater, and attached to the infundibulum. The circular sinus is situated at this point. On detaching the cerebrum from the back-part of the sella Turcica, the tunica arachnoides is very evident. 3. The Third Pair of Nerves, Motores Ocu- lorum, arise from the crura cerebri*, pass outwards and forwards on the outer side of the posterior clinoid process into the cavernous sinus, and run through the foramen lacerum orbitale superius to the muscles of the eye. Between these two nerves are seen the two vertebral arteries, ascending and uniting, to form the basilary ar- tery. 4. The Fourth Pair, Trochleares or Pa- thetici, are very slender, and situated immediately under the edge of the tentorium. This nerve arises from the valvula cerebri, comes out from betwixt the cerebrum and cerebellum, passes by the side of the pons Varolii, and, passing through the cavernous sinus, continues its course through the foramen lacerum or- bitale superius, to supply the obliquus superior muscle of the eye. * The two crura pass obliquely backwards and inwards, so as to converge and meet in front of the tuber annulare; it is from the hollow formed by their convergence, and named by Vicq d'Azyr, fosse det nerfs ecculo-musculaires, that the third pair iri^e. 142 5. The Fifth Pair, Trigemini, are much larger than the fourth, and are situated more out- wards and backwards. Each of these nerves arises, by a number of filaments, from the anterior and lowest part of the crus cerebelli, where the crus unites with the pons Varolii;—it passes forwards, enteis the ca- vernous sinus, where it untwists itself, and forms a flat irregular ganglion, the Ganglion Gasse- rianum, and then divides into three great branches. (1.) Ramus Ocularis.—The ophthalmic nerve of Willis passes through the foramen lacerum orbitale su- perius to the appendages of the eye. (2.) Ramus Maxillaris Superior passes through the foramen rotundum to the upper jaw and face. (3,) Ramus Maxillaris Inferior passes through the foramen ovale to the lower jaw and tongue. 6. The Sixth Pair, Motores Oculorum Externi, or abductores.—This nerve is small, but not so small as the fourth pair; it is seen arising betwixt the pons Varolii and corpora pyramidalia: it enters the cavernous sinus,—it there runs by the side of the carotid artery, and passes through the fo- ramen laceram orbitale superius to the rectus externus oculi- While in the cavernous sinus, it gives off the small twig, which, uniting with filaments from the second branch of the fifth pair, forms the beginning of the intercostal nerve, and passes out of the cra- nium through the foramen caroticum with the carotid artery. " 7 am 7. The Seventh Pair, Nervi Auditorii, con- sists of two portions. *&rrtfz**-* (1.) The Portio Dura, or the fascial nerve, arises tycWm from the crus cerebelli, and comes out from the fossa or groove betwixt the pons Varolii, corpora olivaria, and crura cerebelli. (2.) i he Portio Mollis, or more properly the audi- tory nerve, arises from the inner surface of the fourth ventricle; it has a groove on its surface for receiving the portio dura;—ac ompanied by an artery, they enter the meatus auditorius internus, where the por- tio mollis is distributed to the parts of the internal ear, while the portio dura runs through the aqueduct of Fallopius, and comes out at the stylo-mastoid fora- men below the ear, to form the principal nerve of the face. 8. The Eighth Pair, Par Vagum, arises by numerous filaments from the sides of the corpora olivaria and medulla oblongata. Two distinct fasci- culi are formed, the uppermost called nervus glosso- pharyngeus, the other the proper par vagum;—they unite, run towards the foramen lacerum in basi cranii, pierce the dura mater, and pass out through the anterior part of that hole, having been first joined by the Nekvus Accessorius ad Par Vagum, which runs up from the medulla spinalis through the great occipi- tal foramen. The great Lateral Sinus passes out by the back- part of the same foramen, to form the internal jugular vein; it is separated from the nerve by a slip of carti- lage. 144 9. The Ninth Pair, Linguales, Linguales Medii, Hypoglossi.—This nerve arises from the furrow be- twixt the corpora olivaria and pyramidalia, by several filaments which often pierce the dura mater separately. It passes through the anterior condyloid hole of the oc- cipital bone, to supply the muscles of the tongue. Immediately after leaving the cranium, the eighth and ninth pair, and the ganglion of the intercostal, are con- nected together. 10. The Tenth Pair*, Suboccipitales, arise, on each side, by two bundles, from the extremity of the medulla oblongata, and upper part of the spinal mar- row, pass through the dura mater by the same foramen which gives entrance to the vertebral artery, and run through the foramen magnum occipitale to the muscles at the base of the cranium. The corpora albicantia Willisii, are again seen, two white bodies, on the base of the brain, behind the in- fundibulum, and above the pons Varolii. The Medulla Oblongata remains to be demon- strated. It should be removed from the bone, and ex- amined in an inverted position. On its under surface are seen the two vertebral arteries, ascending from the foramen magnum, and uniting, to form one trunk, the basilar artery. On removing the pia mater, the whole surface ap- pears medullary; but an incision shows it to be inter- mixed with the cineritious substance. The Crura or Pedunculi Cerebri are two • These are now perhaps as frequently described as the first pair of cervical nerves. 145 considerable medullary fasciculi, proceeding from the centre of the medulla of the brain, more immediately from the corpora striata; they unite at an acute angle, and are united to the pons Varolii*. The Crura or Pedunculi Cerebelli are very large, and pass from the medullary part of the cere- bellum which forms the arbor vita to the pons Va- rolii. The Pons Varolii, Tuber Annulare, or Nodus Cerebri, is a medullary protuberance, formed by the union of the crura cerebri and cerebelli, over which it is stretched lilie a bridge: on its surface is a raphe, or transverse fibres passing into a middle longitudinal narrow depression. Below the pons Varolii, and separated from it by a sulcus, are seen four eminences : 1. The two external are named Corpora Oli- varia. 2. The two internal are named Corpora Pyra- midalia, and, by separating these two bodies, me- dullary cords, passing transversely, appear, the nervi intercerebrales. The point of union betwixt the corpora pyramidalia and pons Varolii, is sometimes called foramen ca- cum. The medulla oblongata now contracts itself, and pass- ing through the foramen magnum occipitale, assumes the name of * On making a section of the crura cerebri, near to their union with the pons Varolii, a portion of a dark-brown colour, surrounded with white medullary substance, is seen, termed Locus Niger Crurum Cerebri. N 146 Medulla Spinalis, or the Spinal Marrow.— This part of the nervous or sensorial system must be here described, although its dissection cannot be per- formed till all the muscles of the back are removed, so that the posterior part of the spinal canal may be sawed off. The spinal canal is lined by a strong ligamentous sheath, and the dura mater, is continued down upon this sheath in the form of a funnel. The spinal marrow consists externally of medullary substance, internally of cineritious. It runs down to 'the first lumbar vertebra, where it terminates by nu- merous filaments, which form the cauda equina.—It is closely embraced by the pia mater, while the tunica arachnoides adheres to that membrane very loosely. During the whole of its passage, there is on each side a membranous connection betwixt the pia and dura mater, by distinct slips, irregular and pointed, which connection is named Ligamentum Denticulatum. The arteries of the medulla may be seen running down on its anterior and posterior surfaces ; they are branch- es of the vertebral artery. The spinal accessory nerve is seen arising by small twigs from the posterior bundles of the fourth, fifth, sixth, and seventh cervical nerves ; it then ascends along the spinal canal, enters the foramen, and passes forwards, to accompany the par vagum. The spinal marrow sends oft' twenty-nine pair of spinal nerves, which pass through the foramina form- ed betwixt the bodies of the vertebra. They consist of seven cervical, twelve dorsal, five lumbar, and five sacral pairs of nerves. Each of these nerve6 147 arises in two fasciculi, one from the fore-part, the other from the back-part, of the spinal marrow ; these fasci- culi penetrate the dura mater separately; the posterior bundle forms a ganglion, and afterwards unites with the anterior fasciculus, to form the nerve. A general view of the distribution of the spinal nerves may be usefully subjoined in this place, to com- plete the description of the nerves. 1. The Cervical Nerves consist of seven pairs; they spread their branches over the side of the neck, and to the muscles moving the head and shoulders. The superior nerves send branches to the side of the head, and the inferior to the upper part of the chest and back. They also communicate freely with each other, and with all the neighbouring nerves;—high in the neck, and under the jaw, with the portio dura of the seventh pair, with the fifth, eighth, and ninth pairs, and with the great sympathetic;—towards the middle of the neck, with the descendens noni, the sympathetic and eighth pair, and in the lower part of the neck with the sympathetic. The Phrenic Nerve is formed by branches of the third, fourth, and fifth cervical nerves, passes obliquely down the neck through the thorax, then on each side of the pericardium, and is distributed to the diaphragm. The Axillary Plexus is formed by the principal parts of the trunks of the fourth, fifth, sixth, and seventh cervical, and first dorsal nerves. 2. The Dorsal Nerves are twelve pairs.—They arise from the spinal marrow in the same manner as the cervical. Each nerve emerges betwixt the head- 148 of the ribs, gives twigs to the great sympathetic nerve, and twigs which pierce backwards to the muscles of the back; then, entering the groove in the lower edge of each rib, it accompanies the inter- costal artery, and runs towards the anterior part of the thorax, supplying the great muscles of the chest, giving twigs to the diaphragm, and muscles of the ab- domen. 3. The Lumbar Nerves are five pairs.—They arise in the same manner; their trunks are covered by the psoas magnus muscle. Each nerve gives twigs to the muscles of the loins and back, and to the sympathe- tic nerves, and runs obliquely downwards to supply the abdominal muscles and integuments of the groin and scrotum; but the trunks of these nerves assist in form- ing the nerves of the thigh. 4. The Sacral Nerves are five on each side, arising from the cauda equina. They come out through the anterior foramina, and send small branches to the neighbouring parts; but the great trunks of these nerves are united with the lumbar nerves, to form the nerves of the lower extremity, viz. (1.) The Anterior Crural Nerve, passing out under Poupart's ligament to the extensor muscles of the leg, is formed by branches of the first, secondi third, and fourth lumbar nerves. (2.) The Obturator Nerve, leaving the pelvis by the thyroid holes, and being distributed to the deep- seated muscles on the inside of the thigh, arises from branches of the second, third, and fourth lumbar nerves. (3.) The Ischiatic or Sciatic Nerve, the 149, greatest nerve of the body, passes out from the back- part of the pelvis, through the sacro-sciatic notch, and takes its course along the back of the thigh, to supply the thigh, leg, and foot; it is formed from the two last nerves of the loins and three first of the sa- crum. All these nerves of the spine communicate freely by numerous twigs, and by the intervention of The Great Sympathetic Nerve, or Intercos- tal.—This nerve, originally derived from the sixth pair, and from some filaments of the fifth, passes out of the cranium with the carotid artery. It then descends through the neck, and forms three ganglions in its course, which give twigs to the neighbouring parts, and are joined by filaments from the cervical nerves, and the eighth and ninth pairs. The intercostal then en- ters the thorax, and descends by the side of the ver- tebra, behind the pleura, giving filaments, which, joining with twigs of the eighth pair, form several plexuses to supply the heart, lungs, &c. In the ab- domen it descends on the lumbar vertebra, and at last terminates in the pelvis on the extremity of the coccyx. While in the thorax, it gives off a branch, which; uniting with branches of the dorsal nerves, forms The Anterior Intercostal, or Splanchnic Nerve.—This nerve, passing betwixt the crura of the diaphragm, enters the abdomen, forms the semilunar ganglion, and is distributed by numerous plexuses to all the abdominal viscera. The eighth pair, or par vagum, has also a very long course; it arises in the head, passes through the neck. .n2 150 to which it gives several branches. It enters the tliO' rax anterior to the subclavian artery; here it gives off a remarkable branch, called the Recurrent, because it is reflected round the arch of the aorta on the left side, and round the subclavian artery on the right, and ascends to be distributed on the trachea, oesophagus, and larynx. The nerve then passes through the tho- rax, and, entering the abdomen, terminates in the sto- mach ; in this course it has frequent communications with the great sympathetic, which it assists in forming the different plexuses that supply the thoracic and ab- dominal viscera. It is distributed to the heart, lungs, liver, spleen, stomach, and duodenum. of the vessels of the brain. The arteries ramify largely on the pia mater, before they enter the substance of the brain; they come from two large branches. 1. The Internal Carotid Artery enters the skull by a winding course through the foramen caroti- cum of the temporal bone. After passing through the cavernous sinus, it divides jnto three branches : 1. An- terior cerebri, passing between the two anterior lobes; 2. Media cerebri, entering the fissura sylvii; 3. Ramus communicans, uniting with the basilar. The carotid, while in the cavernous sinus, gives off the arteria oph- thalmica, which passes through the foramen opticum to the eye and its appendages. 2. The Vertebral Artery arises from the sub- clavian, ascends through the foramina in the transverse processes of the cervical vertebra, enters the cranium 151 by the foramen magnum, and gives branches to the du- ra mater and spinal marrow.—Uniting with its fellow, it forms the basilar artery, which gives branches to the internal ear, branches to form the circulus arteriosus, and then divides into two large branches called Poste- riores Cerebri, which supply the back-parts of the cerebrum. The Veins pour their blood into the sinuses, which are numerous. None of these veins require particular attention, except the ophthalmic vein, which passes through the foramen lacerum orbitale superius. The principal sinuses, viz. the longitudinal, the two lateral, the inferior longitudinal, &c. have been described in the dissection of the brain. The remainder of these sinuses are situated in folds of the dura mater, but are not re- gular in their situation. They transmit their blood to the longitudinal and lateral sinuses, which terminate in forming the internal jugular veins. 152 CHAP. VII. DISSECTION OF THE ANTERIOR PART OF THE NECK. SECT. I. OF THE MUSCLES. THE utility of this dissection must be evident, when you consider how many important parts are contained in the fore-part of the neck. The tube which conveys air to the lungs, the vessels which are sent from the heart to the brain, and the nerves which are destined to supply the thoracic and abdominal viscera, are situated in the neck; and all these parts lie imbedded in cellular substance;. hence the dissection is intricate, and re- quires the utmost care in its performance. The muscles of the anterior part of the »neck, are sixteen in number on each side. They may be divided into muscles situated superficially, muscles at the upper part of the neck, and those situated at the lower part. .- The superficial muscles are two. 153 Immediately under the integuments, and adhering to them, I. The Musculus Cutaneus, vulgo, Platysma myoides.—It arises, by slender separate fleshy fibres, from the cellular substance, covering the upper part of the deltoid and pectoral muscles. These fibres form a thin broad muscle, which runs obliquely upwards, and is Inserted into the skin and muscles covering the lower jaw and cheek. This muscle should be dissect- ed in the course of its fibres; the skin, therefore, must be dissected off in an oblique direction from the clavicle to the chin. Use: To draw the skin of the cheek downwards, and, when the mouth is shut, to draw the skin under the lower jaw upwards. Synonyma : Quadratus gena ;—Latissimus colli ;— Thoraco-maxilli-facial. Remove the platysma myoides from its origin, and invert it over the face. Immediately beneath it is seen the external jugular vein, which is formed of branches from the temple, side of the face, and throat. It crosses obliquely over the sterno-mastoi- cleus, passes behind the outer edge of that muscle, and dives beneath the clavicle, to enter the subclavian vein. 2. The SteRno-Cleido-Mastoideus—Arises, by two distinct origins; the anterior, tendinous and fleshy, and somewhat round, from the top of the sternum, near its junction with the clavicle; the posterior or outer, fleshy and flat, from the upper 154 and anterior part of the clavicle. These two origins soon unite, and form a strong muscle, which ascends obliquely upwards and outwards, to be Inserted, tendinous, into the outside of the mas- toid process, and into the transverse ridge behind that process. Use: When one acts singly, it turns the head to one side. W^hen both act together, they bend the head forwards. Synonyma: Sterno-mastoideus et cleido-mastoi- deus ;—Mastoideus ;—Sterno-clavio mastoidien. The muscle should be detached from the sternum and clavicle, and left suspended by its insertion. It is pierced by several branches of the cervical nerves, and, about its middle, it is perforated by the Nervus Accessorius. These nerves-ramify on the neigh- bouring muscles of the neck and shoulder. Between the posterior edge of the sterno-cleido-mastoideus and the fore-part of the trapezius muscles, is seen a quan- tity of loose fatty substance, intermixed with branches of nerves. This fatty substance is watery and granu- lated ; it must not be removed roughly, lest import- ant nerves and vessels be injured; it is continued around the vessels under the clavicle. In the middle of the throat you see, (if) The Os Hyoides, or bone of the tongue, forming the uppermost of the projections beneath the chin. (2.) The Larynx, or upper part of the trachea, consisting of five cartilages, of which two are evident externally, viz. 1. the uppermost and largest is tlv. 155 thyroid cartilage ; 2. the inferior is the cricoid cartilage. The two arytenoid cartilages, and the epiglottis, lie be- hind this. (3.) The Trachea, consisting of cartilaginous rings, and extending into the thorax. (4.) Behind the larynx is situated the pharynx. At the part where the larynx terminates in the tra- chea, the pharynx contracts itself, and forms the oesophagus, or muscular tube, conveying the food to the stomach, which descends behind the trachea, situated rather to the left side of the cervical ver- tebra. These parts are covered by muscles, and on each side of the trachea lie the great vessels and nerves. Muscles at the lower part of the neck are five. 3. The Sterno-Hydoideus—Arises, thin and fleshy, from the upper and inner part of the ster- num, clavicle, and first rib:—It forms a flat narrow muscle. Inserted into the base of the os hyoides. Situation: This pair of muscles is seen on remov- ing the platysma myoides, between the sterno-cleido mastoidei. Use : To pull the os hyoides downwards. Synonyma: Sterno-hyoidien. 4. The Omo-Hyoideus- in'sfs, broad, thin, and fleshy, from the root of the coracoid process, and se- milunar notch of the scapula, ascends across the neck, and forms a middle tendon, where it passes below the sterno-cleido-masioideus. Becoming fleshy again, it 'tins up, and is 156 Inserted into the base of the os hyoides, between its cornu and the insertion of the sterno-hyoideus. Situation: The lower part of this muscle is covered by the trapezius; its middle by the sterno-cleido-mas- toideus; its anterior part is seen on removing the pla- tysma myoides; it crosses over the carotid artery, and internal jugular vein. Use: To pull the os hyoides obliquely down- wards. Synonyma: Coraco-hyoideus;—Scapulo-hyoidien. On dividing the sterno-hyoideus, observe, 5. The Sterno Thyroideus.—This muscle arises, fleshy, from the inside of the sternum, and of the extremity of the first rib; forms a flat muscle, and is Inserted into the inferior edge of the oblique ridge in the ala or side of the thyroid cartilage. Situation: Beneath the sterno-hyoideus. Use: To draw the thyroid cartilage, and conse- quently the larynx, downwards. Synonyma: Sterno-thyroidien. Under the sterno-thyroideus, we find situated the Thyroid Gland, a large reddish mass, situated on the superior rings of the trachea, below the cricoid cartilage; in form somewhat like a crescent, with the cornua turned upwards. 6. The Thyro-Hyroideus—Arises, fleshy, from the upper surface of the oblique ridge in the ala of the thyroid cartilage, and passes upwards, to be Inserted into part of the base, and almost all the cor- nu of the os hyoides. 157 Use: To pull the os hyoides downwards, or the thy- roid cartilage upwards. Situation: Concealed by the sterno-hyoideus. Synonyma: Hyo-thyroideus;—Hyo-thyroidien. 7. The Crico-Thyroideus—Arises, tendinous and fleshy, from the side and fore-part of the cricoid carti- lage, and runs obliquely upwards. Inserted, by two fleshy portions, the first into the lower part of the thyroid cartilage, and the second into its inferior cornu. Situation: On the side of the larynx, and under the sterno-thyroideus. Use: To pull forwards and depress the thyroid, or to elevate and draw backwards the cricoid carti- lage. Synonyma: Crico-thyroidien. The muscles at the upper part of the neck consist of nine pair. 8. The Digastricus—Arises, principally fleshy, from the fossa at the root of the mastoid process of the temporal bone; its fleshy belly terminates in a strong round tendon, which runs downwards and forwards, passes through the fleshy belly of the stylo-hyoideus, is fixed by strong ligamentous and tendinous fibres to the os hyoideus, from which it receives an addition of fibres; it then becomes again fleshy, and runs obliquely up- wards, to be Inserted into a rough sinuosity on the anterior in- ferior edge of that part of the lower jaw called the Chin. Situation: Its posterior belly is covered by the sterno- o 158 cleido-mastoideus; its anterior belly lies immediately under the skin and platysma myoides. Use : To open the mouth, by pulling the lower jaw vdownwards and backwards; and, when the jaws are shut, to raise the larynx, and consequently the pharynx, upwards, as in deglutition. Synonyma : Biventer-maxilla ;—Mastoidi-hyogeni- en. In the triangular space formed by the two bellies of this muscle, and the base of the lower jaw, lies the Submaxillary Gland. It lies upon a flat muscle, the mylo-hyoideus, which is seen between the two bel- lies of the digastricus ; the gland is surrounded by little absorbent glands. 9. The Stylo-Hyoideus—Arises, tendinous, from the middle and inferior part of the styloid process of the temporal bone ; its fleshy belly is generally perforated by the digastricus. Inserted, tendinous, into the os hyoides at the junc- ture of its base and cornu. Situation: The origin of this muscle is situated more inwards than the last, and nearer the base of the cranium; it is the most superficial of three muscles which arise from the styloid process ; sometimes it is accompanied by another small muscle, having the same origin and insertion, the stylo-hyoideus alter. Use: To pull the os hyoides to one side, and a little upwards. Synonyma: Stylo-hyoidien. 10. The Stylo-Glossus—Arises, tendinous and fleshy, from the styloid process, and from a ligament 159 that connects that process to the angle of the lower jaw. It descends, and becomes broader, but less thick. Inserted into'the root of the tongue, runs along its side, and is insensibly lost near its tip. Situation : This muscle lies within and rather above the stylo-hyoideus; underneath it is a ligament, ex- tending from the styloid process to the angle of the os hyoides.—Ligamentous fibres are also seen passing from that process to the inside of the angle of the lower jaw. Use: To move the tongue laterally and back- wards. 11. The Stylo-Pharyngeus—Arises, fleshy, from the root and inner part of the styloid process. Inserted into the side of the pharynx and back-part of the thyroid cartilage. Situation: It is situated deeper, and behind the stylo- glossus. Use: To dilate and raise the pharynx and thyroid cartilage upwards. Synonyma: Stylo-thyro-pharyngien. On removing the submaxillary glands, and detaching the digastric muscle from the os hyoides and chin, we expose the next muscle. 12. The Mylo-Hyoideus—Arisen, fleshy, from all the inside of the lower jaw, between the last dens mola- ris and the middle of the chin; the fibres form a flat muscle, converge, and are Inserted into the lower edge of the base of the os hy- oides. Situation: This muscle unites with its fellow in a 160 middle tendinous line which extends from the os hyoides to the chin; its posterior part is lined by the internal membrane of the mouth; it lies under the digastricus, but is seen betwixt its bellies. Use: To pull the os hyoides forwards, upwards, and to either side. Synonyma: Mylo-hyoidien. The submaxillary gland sends off a duct, which passes behind the posterior edge of the mylo-hyoideus, then runs along the inner surface of this muscle for- wards and upwards, on the inside of the sublingual gland, to open into the mouth on the side of the frenum of the tongue. The Sublingual Gland lies immediately above the mylo-hyoideus, betwixt it and the internal mem- brane of the mouth, where it lines the side and inferior surface of the tongue. It sends off several ducts, which open into the mouth between the root of the tongue and side of the lower jaw. The removal of the mylo-hyoideus exposes a pair of muscles, which are closely attached to one another. 13. The Genio-Hyoideus—Arises, tendinous, from a projection on the inside of that part of the lower jaw which is called the Chin;—it descends, becoming broad- er, and is Inserted into the basis of the os hyoides. Use: To draw the os hyoides forwards and upwards to the chin. Synonyma: Genio-hyoidien. By removing this muscle, or turning it back from its origin from the jaw, we discover the next muscle. 161 14. The Genio-Hyo-Glossus—Arises, tendinous, from a rough protuberance on the inside of the lower jaw, higher up than the origin of the genio-hyoideus; its fibres run forwards, upwards, and backwards, in a very wide and radiated manner, to be Inserted, some into the posterior part of the base of the os hyoides, near its cornu, others into the tip, mid- dle, and root of the tongue. Situation: This muscle lies under the genio-hyoi- deus before, and more outwardly under the mylo-hyoi- deus. Use: According to the direction of its fibres, to draw the tip of the tongue backwards into the mouth, the middle downwards, and to render its dorsum concave; to draw its root and the os hyoides forwards, and to thrust the tongue out of the mouth. Synonyma: Genio-glossus ;—Genio-glosse. 15. The Hyo-Glossus---Arises, broad and fleshy, from half pi the base, and part of the cornu of the os hyoides; tke fibres run upwards, to be Inserted into the side of the tongue. Siluatmi: It is situated more outwardly than the genio-hyo-glossus, and, at its insertion into the tongue, mixes with the stylo-glossus. Use: To move the tongue inwards and down- wards. Synonyma: Basio-cerato-chondro-glossus;—Cerato- glossus;—Hyo-condro-glosse. 16. The Lingualis—Arises from the root of the tongue laterally, and runs forwards between the hyo- glossus and genio-hyo-glossus, to be o 2 162 Inserted into the tip of the tongue, along with part of the stylo-glossus. Use: To contract the substance of the tongue, and bring it backwards. SECT. II. of the vessels and nerves seen in the dissec- tion OF THE NECK. ARTERIES. The carotid artery ascends from the thorax by the side of the trachea; on its outer side it has the internal ' jugular vein, and behind it the par vagum and intercos- tal nerves. All these parts are connected and inclosed by condensed cellular membrane, which forms a kind of *■ sheath for containing them. At the bottom, and in the middle of the neck, the carotid is covered by the sterno- cleido-mastoideus; at the upper part, by adipose mem- brane, absorbent glands, and by the platysma myoides. It lies deep on the muscles of the spine, and gives off no branches, until it reaches the space between the la- rynx and angle of the jaw, just below the cornu of the os hyoides, where it divides into the external and inter- nal carotids. Of the two, the internal carotid is situated most out- wardly; it passes deep to the base of the cranium, where it enters the foramen caroticum, to supply the brain. 163 The external carotid immediately begins to send off branches. Anteriorly it sends off, 1. The A. Thyroidea Superior.—This artery passes downwards and forwards, to ramify on the thyroid gland, where it inosculates with the artery of the other side, and with the inferior thyroid arte- ries. In this course, it sends ramifications to the integuments, the outside of the larynx, the muscles, See and one remarkable branch, the A. Laryngea, which sometimes arises from, the trunk of the exter- nal carotid ; it is a small artery which divides betwixt the os hyoides and thyroid cartilages, to supply the internal parts of the larynx. 2. A. Lingualis, vel Ranina.—The sublingual artery passes over the cornu of the os hyoides, then behind the mylo-hyoideus, over the stylo-glossus, hyo-glossus, and genio-hyo-glossus, to which it gives branches, and terminates in running along the infe- rior part of the tongue from its base to its apex. It gives branches, to the muscles about the chin, and to the substance and back-part of the tongue. 3. A. Maxillaris Externa.—The external maxillary artery passes under the stylo-hyoideus and posterior belly of the digastricus, then buries itself under the submaxillary gland. It runs over the lower jaw before the anterior edge of the masseter muscle, to supply the face. In its passage, it gives off numerous branches— One is worthy of notice, which runs along under the line of the lower jaw, and passing over '-the jaw near 164 the symphysis, supplies the chin. Other twigs sup- ply the submaxillary gland, &c. Posteriorly the carotid sends off, 4. A. Occipitalis.—The occipital artery crosses backwards and upwards, over the internal jugular vein and internal carotid artery, under the belly of the digastric muscle: it passes through a slight groove in the mastoid process below its great fossa, and ramifies on the back-part of the head. A remarkable branch of the occipital passes to-vmrds the base of the skull, to inosculate near the foramen magnum occi- pitis, with branches from the vertebral and posterior cervical arteries. 5. A. Pharyngea is a small branch of the caro- tid, which passes inwards to the pharynx and base of the skull. 6. Posterior Auris, which passes backwards and upwards in the fold between the ear' and scalp, and is distributed on the integuments of the head. The external carotid ascends behind the angle of the jaw, and enters the parotid gland, where it divides into, 7. A. Maxillaris Externa. 8. A. Temporalis. 9. A. Transversalis Faciei. These arteries will be described in the dissection of the face. veins. The Internal Jugular Vein is a continua- tion of the lateral sinus which passes through the 165 foramen lacerum in the base of the cranium. It comes out deep from under the angle of the jaw, and in its course down the neck, it runs on the outer side of the carotid artery, before it reaches the thorax; it passes rather more forwards than the artery, to join the subclavian vein. Its branches accompany the ramifications of the ex- ternal carotid. At first the vein which accompanies each artery is a single branch, but it soon subdivides, so that two veins accompany one artery. NERVES. 1. The Eighth Pair, or Par Vagum.—On separat- ing the internal jugular vein, and trunk of the carotid artery, the par vagum is seen lying in the same sheath of cellular substance with those vessels. It lies in the triangular space formed betwixt the back-part of the artery and vein, and the subjacent muscles. This nerve comes out of the foramen lacerum with the jugu- lar vein; hence it adheres to that vein more closely than to the artery or muscles ; it runs clown the neck behind these vessels. In this course it gives off several nerves. (1.) At the base of the cranium, it sends off seve- ral filaments, which are connected with the other nerves coming out of the base of the skull, such as the ninth pair, the superior cervical ganglion of the inter- costal, Sec. (2.) Nervus Glosso-Pharyngeus is sent off from the eighth pair, deep under the angle of the jaw. It passes behind the carotids towards the muscles arising 166 from the styloid process; one principal branch of it passes between the stylo-pharyngeus and stylo-glossus to the tongue, while other twigs run behind the stylo- pharyngeus, to supply the pharynx. (3.) Nervus Laryngeus Superior, vel Inter- nus.—The superior or internal laryngeal nerve passes behind the internal carotid artery, obliquely, down- wards and forwards; then, under the hyo-thyroideus muscle, it plunges betwixt the os hyoides and thyroid cartilage, accompanying the laryngeal artery, and sup- plying the internal parts of the larynx. (4.) In the neck, also, the par vagum gives off fila- ments to the cervical ganglions of the intercostal nerve, and to communicate with the other nerves of the neck. Filaments also unite with twigs of the intercostal, and run down over the carotid artery to the great ves- sels of the heart, where they form the superior cardiac plexus. The par vagum enters the thorax by passing be- twixt the subclavian artery and vein. 2. The Intercostal, or Great Sympathetic Nerve.—This nerve lies behind the carotid, in the cellular membrane, betwixt that vessel and the mus- cles covering the vertebra of the neck. It is distin- guished from the par vagum by being smaller, lying nearer the trachea, and adhering to the muscles of the spine ; also by its forming several ganglions. It arises from the sixth pair in the cranium, and comes out by the same foramen as the carotid artery. Immediately after its exit from the skull, it forms the Superior Cervical Ganglion, which is very long, and of a reddish colour. The nerve afterwards 167 becomes smaller, and descends; and opposite the fifth or sixth cervical vertebra, it forms another swel- ling, the Inferior Cervical Ganglion. Some- times it has another ganglion about the fourth or fifth vertebra of the neck, the Middle Cervical Gang- lion; but this is not a constant appearance. The nerve then passes behind the subclavian artery into the thorax. The branches of the intercostal nerve are nume- rous, and they generally pass off from the ganglions. Immediately below the base of the cranium, twigs go to the eighth and ninth pairs, and to the upper cervical nerves. In the middle of the neck, some twigs pass over the carotid; others go to the parts covering the trachea, and uniting with filaments of the par vagum, form the external laryngeal nerves; others unite with the descendens noni, or descending branch of the ninth pair, and some filaments assist the twigs of the par va- gum to form the superior cardiac nerve, hi the lower part of the neck, twigs are sent to communicate with the cervical nerves, Sec. 3. The Ninth Pair, Nervus Hypo-glossus, or Lingual nerve, having left the skull by the anterior con- dyloid foramen, is connected with the eighth pair and intercostal nerve. Like them, it lies deep, and comes out from under the angle of the jaw. It is seen pass- ing from behind the internal jugular vein, and then over the carotid artery, running betwixt these two vessels. It next passes under the mylo-hyoideus, running over the stylo-glosous, hyo-glossus, and genio-hyo-glossus, which last muscle its numerous branches perforate. 168 Branches.—While the nerve is passing betwixt the jugular vein and the carotid artery, it sends off the Descendens Noni—This small and delicate nerve descends on the fore-part of the vein and artery, and is distributed to the muscles on the anterior part of the trachea. It is joined by filaments of the cervical nerves. 4. The Lingual Branch sent off by the third branch of the fifth pair of nerves, is also seen in the dis- section of the neck. It is found under the mylo-hyoi- deus ; it lies close upon the lower edge of the jaw-bone, betwixt the inferior edge of the pterygoideus internus and the upper part of the mylo-hyoideus. It gives nu- merous twigs to the sublingual gland and submaxillary duct, which are situated near it, and is lost in the sub- stance of the tongue. 5. Nervus Accessohius ad Par Vagum.—The accessory nerve, having passed out of the cranium with the par vagum, separates from it, passes behind the internal jugular vein obliquely downwards and backwards; it perforates the mastoid muscle, and is dis- tributed to the trapezius and muscles about the shoul- der ; it is much connected with the third and fourth cer- vical nerves. 6. The Seven Cervical Nerves come out from the foramina betwixt the vertebra of the neck. They send numerous branches to the muscles, &c. on the side of the neck, and communicate by filaments with all the other nerves in the neck. In this stage of the dissection, we may also see, 7. The Phrenic Nerve, formed by branches of the third and fourth cervical nerves.—This small nerve 169 lies upon the belly of the anterior scalenus muscle, and dives into the thorax, betwixt the subclavian artery and vein. 8. The Recurrent Nerve, a branch sent off from the par vagum in the thorax, is also seen in the neck. Dissect between the under surface of the trachea and cesophagus at the lower part of the neck, and you will find the recurrent nerve situated there. 9. The upper part of the Great Brachial Plex- us may be seen, arising on the side of the neck, fro the lower cervical nerves, and passing behind the ante :ior scalenus, to reach the arm. CHAP. VIIL DISSECTION OF THE THORAX SECT. I. OF THE MUSCLES WHICH LIE UPON THE OUTSIDE OF THE THORAX. IN removing the integuments from the fore-part of the thorax, the pectoralis major and interior edge of the deltoid muscle should be dissected in the course of their fibres ; and to do this, it will be necessary to re- member that the fibres run obliquely from the sternum T 170 and clavicle to the upper part of the os humeri*. They are not covered by any fascia, but by a condensed cellu- lar membrane, which is similar to a thin aponeurosis, and is with difficulty dissected away, unless it be done very regularly. Three pair of muscles are described in this dissec- tion. 1. The Pectoralis Major—Arises, tendinous, from the anterior surface of the sternum, its whole length; fleshy, from the cartilages of the fifth, sixth, and sometimes the seventh ribs, and from two anterior thirds of the clavicle. The fleshy fibres run obliquely across the breast, and, converging, form a strong flat tendon, which is Inserted into the ridge of the os brachii on the out- side of the groove for the long tendon of the biceps flexor cubiti. Situation: The belly of this muscle is superficial. It is separated from the deltoid muscle by cellular membrane, and fat, by the cephalic vein, and a small artery, named A. Thoracica Humeraria. Its tendinous fibres, arising from the sternum, are inter- laced with those of the opposite, so as to form a kind of fas,ia covering the bone ; and the origins from the ribs are intermixed with the obliquus externus abdo- minis. The clavicular and thoracic portions of the muscle are separated by a line of cellular membrane. The tendon is covered by the anterior edge of the deltoid; it forms the anterior fold of the arm-pit, and appears twisted, for the fibres which proceed from the thoracic portion of the muscle, seem to pass behind * Called also, Os Brachii. 171 tuose proceeding from the clavicle, and to be inserted into the os humeri somewhat higher up. Use: To move the arm forwards, and obliquely up- wards, towards the sternum. Synomjma: Pectoralis;—Sterno-costo-clavio-hume- ral. The pectoralis major should be lifted up from its ori- gin, and suspended by its tendon.—This will expose the next two muscles. 2. The Pectoralis Minor—Arises, by three ten- dinous and fleshy digitations, from the upper edges of the third, fourth, and fifth ribs, near their cartilages; it forms a fleshy triangular belly, which becomes thick- er and narrower as it ascends, and is Inserted, by a short flat tendon, into the anterior part of the coracoid process of the scapula. Situation: The belly of this muscle is covered by the pectoralis major ; the tendon passes under the an- terior edge of the deltoid, and is connected at its inser- tion with the origins of the coraco-brachialis, and of the short head of the biceps flexor cubiti, and also with the ligamentum proprium scapula anticum, a strong liga- gament, which passes from the external edge of the co- racoid process, to be affixed to the posterior margin of the acromion of the scapula. Use: To draw the scapula forwards and down- wards, and, when that bone is fixed, to elevate the ribs. Synonyma: Serratus anticus ;—Serratus minor anti- cus ;—Costo-coracoidien. 3. The Subclavius—Arises, by a flat tendon, from 172 the cartilage of the first rib, and forms a broad fleshy belly, which is Inserted into the inferior surface of the clavicle, be- ginning about one inch from the sternum, and continu- ing as far as the ligamentous connection of the clavicle to the coracoid process. Situation: This muscle is situated between the cla- vicle and sternum, concealed by the pectoralis major, and anterior part of the deltoides. Use : To draw the clavicle downwards and forwards, and perhaps to elevate the first rib. Synonyma: Costo-claviculaire. Having lifted up the pectoralis minor from its ori- gin, the situation of the subclavian vessels which pass under the clavicle, and over the first rib, may be seen. (See the dissection of the Axilla.) SECT. II. OF THE PARTS CONTAINED WITHIN THE CAVITY OF THE THORAX. The cavity of the thorax may now be opened, by cutting through the cartilages of the ribs on each side, and separating the lower part of the sternum from the diaphragm. That bone must then be lifted upwards, and the first and second parts of which it is composed divided by an incision along the inner surface of their junction ; or the whole sternum may be removed, by separating it at its articulations with 173 the clavicle. The latter method is preferable, as it allows us to examine more readily the great vessels passing out of the thorax. On looking under the sternum, while it is lifted up, we see the Mediastinum, separating, as it is gra- dually torn from the posterior surface of the sternum, into two layers, and thus forming a triangular cavity. This cavity is artificially produced, and is entirely owing to the method of raising the sternum. When the sternum is laid back or removed, the following parts are to be observed : The Mediastinum, now collapsed, dividing the thorax into two distinct cavities, of which the right is the largest. The lungs of each side lying distinct in these cavities. The Pericardium, containing the heart, situated in the middle of the thorax, between the two lamina of the mediastinum, and protruding into the left side. The internal surface of the pleura, smooth, co- lourless, and glistening, lining the ribs, and reflected over the lungs. 1. The Pleura.—Each side of the thorax has its particular pleura:—The pleura are like two blad- ders, situated laterally with respect to each other; by adhering together in the middle of the thorax, and passing obliquely* from the posterior surface of the * They run obliquely, not being in general attached to the middle of the sternum, but towards its left side, especially at the lower part of the bone, near the diaphragm. Besides the pericardium, the mediastinum contains betwixt its lamina some adipose membrane and absorbent glands. r 2 174 sternum to the dorsal vertebra, they form the me- diastinum.—The pleura lines the ribs, and the upper surface of the diaphragm, and is reflected over the lung, which is in fact behind it; it forms the liga- mentum latum pulmonis, a reflection of this mem- brane, which connects the inferior edge of the lungs to the spine and diaphragm. 2. The Lungs.—Colour, reddish in children, greyish in adults, and bluish in old age.—Shafie, cor- responding to that of the thorax, somewhat pyra- midal, convex towards the ribs, concave towards the dia- phragm, and irregularly flatted next the mediastinum. Division (1.) The Right Lung is the largest, and is divided into three lobes, two greater ones, and an intermediate lesser lobe. (2.) The Left Lung has two lobes, and also a square notch opposite the apex of the heart. Into the sulci or grooves which form the divisions of the lungs into lobes, the pleura enters; that part of the lung which is affixed to the spine, is called its root: it is the part by which the great vessels enter. 3. The Pericardium is a strong, white, and compact membrane, smooth, and lubricated upon the inside, forming a bag for containing the heart, and having its inner lamina reflected over the substance of the heart itself. 4. When you slit open the fore-part of the peri- cardium, you expose the Heart. The right ven- tricle protrudes; the right auricle also is towards you; while the left auricle is retired, and its tip is seen lapping round upon the left ventricle. From 175 under this tip of the left auricle, a branch of the co- ronary vein, and one of the coronary artery, ramify towards the apex of the heart, marking the situation of the septum cordis. The left ventricle will be found firm, fleshy, and resisting, whilst the right ventri- cle is more loose, and seems partly wrapt round the other. The heart is situated obliquely in the middle of the breast; its posterior surface is flat, and lies upon the diaphragm; its apex is turned forwards, and towards the left side, so that, in the living body, it is felt strik- ing between the fifth and sixth ribs, at the point where the cartilages and bony extremities are united. The Vena Cava Superior is seen coming down from the upper angle of the pericardium. The Inferior Ca- va is seen coming up through the diaphragm; but only a very small part of this vein is covered by the pericardium; the two veins enter the right auricle. The Right Auricle is turned forwards, and might be called the anterior; it generally appears black, by the blood shining through its thin coats. The Right Ventricle is situated almost directly opposite. The Pulmonary Artery arises from the right ventricle; its root is concealed by the right auricle; it ascends on the left side of the aorta; it divides into, 1. the right pulmonary artery, which passes under the arch of the aorta, crosses behind it and the vena cava supe- rior to the right lung, and is the longest; and, 2. the left pulmonary artery, which passes to the left lung, crossing the descending aorta anteriorly. The Pul- monary Veins enter the left auricle, two veins come from each lung; the right veins are longest as they pass 176 behind the vena cava superior. The left auricle is si- tuated on the left side of the right auricle, and some- what behind it; its tip is seen lapping round upon the Left Ventricle; this is situated behind and on the left side of the right ventricle; its substance is stronger and more firm to the touch. The Aorta arises from the back-part and right side of the left ventricle; its root is covered by the pulmonary artery; it then as- cends betwixt that artery and the vena cava superior. Immediately from the root of the aorta, within the peri- cardium, the two coronary arteries are sent off to sup- ply the heart itself. SECT. III. DISSECTION OF THE GREAT VESSELS OF THE HEART. The Vena Cava Superior will be seen de- scending before the root of the lungs, and on the right side of the aorta. Immediately before perforat- ing the pericardium, it is joined upon its posterior part by the vena azygos, which comes forwards from the spine, returning the blood from the intercostal spaces. Behind the sternum, and just above the arch of the aorta, the superior cava is seen receiving two great branches. 1. A branch coming from the right side, formed 177 by the right subclavian vein, and the right internal ju- gular. 2. A larger branch coming from the left side; it is formed by the left subclavian and left internal jugular, which unite to form a trunk. This trunk crosses be- fore the arteries arising from the arch of the aorta, and then enters the superior vena cava. Into the posterior part of the angle formed by the union of the left sub- elavian and the left jugular, the thoracic duct empties itself. On each side, the internal jugular vein descends along the neck by the side of the carotid, while the subclavian vein comes from the arm. The Vena Cava Inferior, immediately after pass- ing through the diaphragm from the abdomen, enters the pericardium. The Aorta leaves the heart opposite the fourth dorsal vertebra; it crosses over the pulmonary artery, ascends obliquely upwards, backwards, and to the right side, as high as the second dorsal vertebra. Here it forms an Arch or incurvation, which passes from the right to the left side, and at the same time ob- liquely from before backwards; it then comes in con- tact with the upper part of the third dorsal vertebra, and descends along the spine in the posterior medi- astinum. This arch of the aorta is situated behind the first bone of the sternum, behind and somewhat be- low the left branch of the vena cava superior. From the upper part of the arch come off three large arteries. 1. The Arteria Innominata, or common trunk 178 of the right carotid and subclavian, ascends about an inch, and bifurcates into, a, The right carotid, which ascends in the neck by the side of the trachea. b, The right subclavian, which passes outwards to the arm. 2. The left carotid. 3. The left subclavian comes off from the extremity of the arch. The arch of the aorta also gives off some small twigs which pass to the pleura, the mediastinum, and thymus. The Thymus is a soft glandular body, lying, before the lower part of the trachea and great vessels of the heart, a little higher than the tops of the two pleura. It is very large in the fcetus, smaller in adults, and nearly disappears in the aged. Where the aorta begins to descend, it is connect- ed to the pulmonary artery by a ligament, which, in the foetus, was a large canal, the Ductus Arte- riosus. COURSE OF THE SUBCLAVIAN ARTERY ON EACH SIDE. The subclavian artery passes upwards and out- wards, runs under the clavicle, and over the middle of the first rib; it passes between the bellies of the anterior and middle scaleni muscles, then runs under the arch of the pectoralis minor, and enters the axilla, where it assumes the name of Axillary Artery. 179 The order in which the following arteries are sent off from the subclavian varies much; sometimes they come off singly, at other times in large trunks, which subdivide. Backwards the subclavian sends off, 1. The Vertebral Artery.—This artery arises from the back-part of the subclavian, passes outwards and enters the foramen in the transverse process of the last cervical vertebra, and ascends through the trans- verse processes of the vertebra, to enter the foramen magnum of the occipital bone. 2. The Inferior Thyroid Artery ascends ob- liquely inwards, passes behind the internal jugular vein, to ramify on the thyroid gland,, where it inos- culates largely with the superior thyroid arteries. Branches from this artery pass to the trachea and oesophagus, to the muscles of the neck, and of the scapula: one of these is the supra scapulary artery. (See the account of the branches of the axillary ar- tery.) 2. A. Cervicalis Anterior, vel Profunda, passes deep to the muscles situated on the fore-part of the cervical vertebra, and ascends as high as the base of the skull. 4. A. Cervicalis Posterior, vel Superficialis, is larger than the last; it ascends obliquely outwards, generally passes betwixt the transverse processes of the last cervical and first dorsal vertebra, and ascends on the back-part of the neck, deeply seated; some of its branches pass down the back superficially. Anteriorly, the subclavian artery gives offi 180 5. A. Mammaria Interna. The internal manr- mary arises from the fore-part of the subclavian, oppo- site the cartilage of the first rib; it runs down on the inside of the cartilages of the ribs, and terminates in the abdominal muscles, where it inosculates with the epigastric. It is a large artery, and its branches are very numerous. They pass to the external muscles of the chest, to the intercostal muscles, pleura, Sec. It also sends off the Arteria Phrenica Superior, vel comes nervi phrenici, which, with two veins, ac- companies the phrenic nerve to the diaphragm. 6. The subclavian artery gives twigs to the root of the neck, and to the muscles about the scapula. 7. A. Intercostalis Superior. Frequently a trunk comes off from the subclavian, especially on the right side, which passes downwards and backwards, and lodges itself by the spine, to supply the two or • hree superior intercostal spaces. COURSE OF THE SUBCLAVIAN VEIN. The subclavian vein is situated anteriorly to the sub- clavian artery; it passes inwards behind and under the subclavius muscle, and before and over the belly of the anterior scalenus (so that this last muscle lies betwixt the vein and artery). It runs over the first rib, from under the arch of the pectoralis minor, where it is found in contact with the axillary artery, and is called the Axillary Vein. The branches of this vein accompany and correspond to the ramifications of the subclavian artery, returning 181 the blood from the thyroid gland, neck, chest, inter- costal spaces, &c. The subclavian vein also receives the internal jugular, which passes down behind the cla- vicle. THE COURSE OF THE BRACHIAL PLEXUS OF NERVES May also be examined. This plexus is formed by branches of the four lower cervical and first dorsal nerves, which pass between the anterior and middle scaleni muscles into the axilla. In this passage they are situated higher up than the artery. A considerable part of the scaleni muscles may now be seen ; the upper insertion of these muscles must be dissected with the muscles of the back-part of the neck. 1. The Scalenus Anticus—Arises, by three ten- dons, from the transverse processes of the fourth, fifth, and sixth vertebra of the neck. Inserted, tendinous and fleshy, into the upper edge of the first rib, near its cartilage. Synonyma: Scalenus prior;—First scalenus;— Anterior portion of the first scalenus;—Trachelo- costal. 2. The Scalenus Medius—Arises, tendinous, from the transverse processes of all the vertebra of the neck. Inserted into the upper and outer part of the first rib, from its root to within the distance of half an inch from the scalenus anticus. 182 Synonyma: Second Scalenus;—posterior portion of the first scalenus;—Trachelo-costal. 3. The Scalenus Posticus—Arises, tendinous, from the transverse processes of the fifth and sixth ver- tebra of the neck. Inserted into the upper edge of the first rib, near the spine. Synonyma: Third scalenus;—Scalenus secundus ;— Trachelo-costal. Situation: These muscles are covered before by the sterno-mastoideus and trapezius, behind by the trape- zius and levator scapula; but the scaleni are so con- nected with the muscles of the spine, that the whole of them cannot be demonstrated till the muscles of the back and neck are dissected. Use of these three muscles: To bend the neck to one side, and, when the muscles of both sides act, to bend it forwards; or, when the neck is fixed, to elevate the ribs, and dilate the chest. j SECT. IV. DISSECTION OF THE AXILLA, OR ARM-PIT. There is a considerable resemblance in the dis- section of the axilla to that of the ham or groin; in each of these situations we meet with important blood-vessels and nerves, closely connected together, 183 embedded in adipose membrane, and seated in the flex- ure of a joint. The axilla is formed by two muscular folds which bound a middle cavity. The anterior fold is formed by the pectoralis major passing from the thorax to the arm, the posterior by the latissimus dorsi coming from the back. In the intermediate cavity there is a quantity of cel- lular membrane and absorbent glands, covering and connecting the great vessels and nerves. This cellular and adipose membrane is continued from the interstice above the clavicle betwixt the edges of the trapezius and mastoid muscles. All the space before the root of the neck above the first rib, and under the clavicle and coracoid process of the scapula, and the interstices of the muscles passing through that space, are filled up by a quantity of adipose membrane ; and this is not exactly similar to the fat in other parts of the body ; it is more granulated, watery, and of a reddish colour ; it surrounds the great vessels and nerve, ren- dering the dissection both tedious and difficult. The Axillary Vein will be found lying ante- rior to the artery, that is, nearer the integuments. It seems to be a continuation of the basilic vein, which runs along the inside of the arm quite superficial, and of the two or three vena satellites, or veins which accompany the brachial artery- The axillary vein receives branches corresponding to the ramifications of the artery. Passing under the clavicle, it be- comes the subclavian vein, and runs over the first rib, 184 and before the anterior scalenus muscle into the tho- rax. Deeper seated, and immediately behind the axillary vein, lies the Axillary Artery. It is seen coming from under the clavicle; from under the arch formed by the pectoralis minor, it comes over the middle of the first rib, and between the anterior and middle scaleni muscles. In the axilla it is surrounded by the meshes of the nerves, and runs along the inferior edge of the coraco-brachialis muscle ; when it has passed the anterior edge of the pectoralis major, it assumes the name of the Brachial Artery. The branches of the axillary artery are, 1. A. Mammaria Externa, called also, A. Tho- racica Externa.---The external mammary artery consists of three or four branches which run down- wards and forwards obliquely over the chest. These branches sometimes come off separately from the axillary artery, at other times by one or two common trunks, which subdivide. They supply the pectoral muscles and mamma. Some of their branches pass to the muscles of the shoulder, to the side of the chest, and to the muscles on the inside of the scapula. 2. A. Scapularis Interna, Supra-scapularis, or Dorsalis Scapula, is sent off from the back-part of the axillary artery. It runs across the bottom of the neck towards the root of the coracoid process, and passes through the semilunar notch in the superior costa of the scapula; it supplies the supra-spinalus 185 muscle, and then passes under the acromion, to ramify on the muscles below the spine of the scapula. It is generally a branch of the A. Thyroidea Inferior, and is then named A. Transversalis Humeri. 3. A. Scapularis Externa, Infrascapularis, or Thoracica Posterior, arises from the under and back part of the axillary artery, attaches itself to the inferior costa of the scapula, where it splits into two great branches: 1. A large branch, which passes to the outer surface of the scapula bdow the spine, and has its principal ramifications close upon the bone. 2. The other branch (which is larger) passes to the inner surface of the scapula, supplies the subscapularis, and sends branches downwards to the muscles of the back and loins. 4. Arteria Circumflexa Humeri Posterior, Humeralis, or Reflexa Articularis, arises from the low- er and fore-part of the axillary artery; and runs back- wards close to the bone, surrounds its neck, and is lost on the inner surface of the deltoid ; it gives also twigs to the joint and neighbouring muscles. 5 A. Circumflexa Anterior is a much smaller artery, often a branch of the circumflexa posterior; it encircles the neck of the bone on its fore-part, and is lost on the inner surface of the deltoides, where it inosculates with the posterior circumflex artery. The Great Brachial Nerves accompany the subclavian artery over the first rib. In the axilla they are united by numerous cross branches, forming tue Axillary or Brachial Plexus, which is continued from H2 186 the clavicle as low as the edge of the tendon of the latissimus dorsi, and which surrounds the axillary ar- tery with its meshes. From the axillary plexus seven nerves pass off. 1. Nervus Supra-scapularis, Scapularis Exter- nus, Scapularis.—This nerve comes off from the upper edge of the plexus ; it crosses the axilla at the highest part, runs towards the superior costa of the scapula, accompanies the external scapular artery through the semilunar notch, and supplies the muscles on the poste- rior surface of the scapula. 2. N. Circumflexus, Articularis, Axillaris, or Humeralis, lies deep: it passes from the back-part of the plexus, goes backwards round the neck of the bone, accompanying the posterior circumflex artery, and is distributed to the musculus deltoides, and the muscles on the outside of the arm. Small nerves also pass from the axillary plexus to the subscapular muscle, the teres major, latissimus dorsi, and pectoral muscles. 3. The External Cutaneous Nerve, or Nervus-Mus- culo-cutaneus. 4. The Radial Nerve. 5. The Ulnar Nerve. 6. The Muscular or Spiral Nerve. 7. The Internal Cutaneous Nerve. These five nerves will be described in the dissection of the arm and fore-arm. 187 SECT. V. DISSECTION OF THE POSTERIOR MEDIASTINUM*, AND OF THE NERVES AND VESSELS WHICH HAVE THEIR COURSE THROUGH THE THO- RAX. Course of the Phrenic Nerve through the thorax.—On each side this nerve is seen entering the thorax betwixt the subclavian artery and subclavian vein ; it then proceeds downwards and forwards before the root of the lungs, and on the outside of the pericardium, betwixt that bag and the pleura; it is lost on the diaphragm. The left phrenic nerve has a somewhat longer course than the nerve of the right side, as it passes over the pericardium, where that bag covers the apex of the heart. This nerve is accompanied by one artery and two veins; some twigs pass from the phrenic nerve into the abdomen, to the liver, 8cc. Behind the arch of the aorta and great vessels pass- ing from the heart, is seen the Trachea. It en- ters the thorax between the two pleura, and, oppo- site the third or fourth dorsal vertebra, bifurcates into two parts : one of which passes toward the right, the other toward the left, to enter the lung of each side. By folding back the lungs towards the left side of the chest, we expose the pleura reflected from the * By Posterior Mediastimtm is designed that part of the medi,. astinum situated behind the root of the lungs. 188 under surface of the root of the lungs to the spine and ribs. A triangular space is formed betwixt the two pleura and the bodies of the dorsal vertebra; this space or cavity is named the cavity of the pos- terior mediastinum. It contains many important parts, and must therefore be carefully dissected. But first let us attend to the course of the inter- costal, or great sympathetic nerve, which is seen run- ning by the side of the spine. The Intercostal Nerve, where it enters the thorax, is situated behind the great vessels ; close upon the articulation of the first rib with the body of the first dorsal vertebra, it forms a ganglion, a twig of which fairly encircles the subclavian artery, while other filaments are entwisted round the root of the vertebral artery. The intercostal nerve then descends along the thorax ; it lies upon the heads of the ribs, where they are articulated with the vertebra; it receives additional branches from all the dorsal nerves, and in each intercostal space it forms a gang- lion. This nerve may be dissected with greater fa- cility when the lungs are removed, and the ribs sawed off near the spine, which will enable the dissector to trace its branches more fully. It lies behind the pleura, but is seen through it; it passes into the abdomen by the side of the spine, running through the fibres of the small muscle of the diaphragm. Branches of the Intercostal in the Thorax. The Anterior Intercostal, or Splanchnic Nerve, should be attended to. It is formed by 189 three or four twigs, which come off from the inter- costal betwixt the fourth and eighth dorsal vertebra; these twigs, passing forwards on the bodies of the ver- tebra, unite to form the splanchnic nerve, which may be traced entering the abdomen, betwixt the crura of the small muscle of the diaphragm. From the intercostal, also, twigs are given off, which assist the branches of the par vagum, and of the dorsal nerves, in forming several plexuses to supply the visce- ra of the thorax. The right intercostal nerve lies under the pleura by the right side of the spine. Still nearer the middle of the spine, you see the Vena Azygos. In dissecting, it is found situated betwixt the right intercostal nerve and the aorta; it begins below from ramifications of the lumbar arteries, which pierce the small muscle of the diaphragm. This vein ascends along the spine, receiving veins from each of the intercostal spaces of the right side, and, about the middle of the back, it receives a considerable trunk, which comes from under the aorta, and returns the blood from the left side of the thorax. At the fourth dorsal vertebra, the vena azygos leaves the spine; it makes a curve forward, and empties its blood into the back-part of the vena ca- va superior, immediately before that vein enters the pe- ricardium. Descending through the posterior mediastinum, will be also found the Aorta. This great artery, having formed its arch, comes in contact with the third dorsal vertebra, and is now called the Descending Aorta, or Thoracic Aorta. It descends along the bodies of the dorsal vertebra, rather on their left side; it lies behind 190 the oesophagus, and passes betwixt the crura of the dia- phragm into the abdomen. Branches of the Aorta in the Thorax. 1. A. Intercostales Inferiores.—The arteries which supply the three or four superior intercostal spaces, generally come off in one common trunk, which afterwards subdivides. The Intercostalis Superior, on the right side, is mostly sent off by the subclavian; on the left side, by the aorta. The Inferior Intercostals are eight or nine in num- ber on each side of the thorax; they come off separate- ly from the side or back-part of the aorta, and seem to tie that great artery to the spine. Each intercostal ar- tery passes immediately into the interval betwixt two ribs, and there subdivides into, (L) A branch which perforates between the heads of the ribs to the muscles of the back; this branch also gives twigs which enter the spinal canal. (2.) The continued trunk of the artery runs for- wards, in the interval of the two ribs, giving many branches to the intercostal muscles. When it reaches the anterior part of the thorax, it is lost in the mus- cles. Each intercostal artery is accompanied by one or two veins, branches of the vena azygos, and by an intercos- tal or dorsal nerve. 2. A. Bronchiales are two, sometimes three, small twigs of the aorta, one of which passes to the lungs on each side; they sometimes arise from the sub- clavian and superior intercostal. 3. Small arteries pass forwards from the aorta on 191 the oesophagus, named A. CEsophagea ; others run to the pericardium and pleura. The dissector also finds in the posterior mediasti- num the Thoracic Duct. He must look for it behind the oesophagus, betwixt the vena azygos and aorta; it is collapsed, and appears like cellular mem- brane condensed, and can oniy be distinguished .-when inflated or injected; it was seen in the abdomen close to the aorta, and passing into the thorax between the crura of the diaphragm. It ascends along the posterior mediastinum, and, about the fourth dorsal vertebra, passes obliquely to the left side, behind the aorta descendens, and behind the great arch of the aorta, until it reaches the left carotid artery. It runs behind this artery, and behind the left internal jugu- lar vein; and, after forming a circular turn or arch (the convexity of which is turned upwards), it des- cends, and enters the left subclavian vein at the point where that vein is joined by the left internal jugular. In its course along the spine, the thoracic duct fre- quently splits into two branches, which re-unite. The absorbents of the right superior extremity, and of the right side of the head and thorax, usually form a trunk, which enters the right subclavian vein. The CSsophagus is also situated betwixt the lay- ers of the posterior mediastinum. It lies immediately before the aorta, but rather towards its left side; it is seen descending from the neck behind the trachea; it passes through an opening in the lesser muscle of the diaphragm, and immediately expands into the stomach. 192 Behind the trachea and vessels going to the lungs, and on the fore-part of the oesophagus, we meet with a congeries of lymphatic glands. COURSE OF THE PAR VAGUM, OR EIGHTH PAIR OF NERVES, IN THE THORAX. From the neck, the par vagum passes betwixt the subclavian vein and artery into the thorax; it imme- diately sends off a large branch, the Recurrent Nerve, back into the neck. On the right side, this branch twists round under the arteria innomina- ta; on the left side, under the arch of the aorta, it ascends behind the carotid, and lodges itself betwixt the trachea and oesophagus, to both of which it gives branches. The par vagum, having given off the recurrent, descends by the side of the trachea, and behind the root of the lungs. It here sends off numerous fila- ments to the lungs, which, uniting with twigs from the great sympathetic, form the Anterior and Posterior Pulmonary Plexuses; these plexu- ses lie on the anterior and posterior surfaces of the root of the lungs. Other twigs of the par vagum pass, to form the inferior Cardiac Plexus about the peri- cardium. The trunk of the eighth pair soon reaches the oeso- phagus ; the left par vagum runs on the fore-part of the oesophagus, the right nerve on its back-part. Here they split on into several branches, which unito again, and form a Plexus. This plexus is called the Oeso- phageal. The" two nerves continue their course 193 along the oesophagus, and pass with it through the dia- phragm, to ramify on the stomach, and form the sto- machic plexus. The twelve dorsal or intercostal nerves are also seen in this dissection, emerging from the spinal canal, be- tween the bodies of the vertebra, and supplying the in- tercostal muscles, Sec. SECT. VI. dissection of the heart, when removed from the body. The heart consists of three tunics or coats. 1. An external smooth one, which is a reflection of the inter- nal lamina of the pericardium. 2. A middle muscular coat. 3. A smooth internal coat, which is a continua- tion of the internal coat of the great veins and arteries. In the right side of the heart we always meet with a considerable quantity of coagulated blood. In the left side there is much less. Slit open with the scissars the two vena cava on their fore-part, the inner surface of these veins, and of the right auricle, will be seen lined by a smooth membrane; and in the auricle, the musculi pectinati, or bundles of muscular fibres, will be seen projecting. At the point of union between the two cava, there is a projection formed by the thickening of the muscular coat, the Tuberculum Loweri. The Septum Au- ricularum is seen separating the right from the R 194 left auricle;—observe that it is thin, that in it there is an oval depression, named Fossa Ovalis. Round this fossa the fibres are thicker, forming the annulus ovalis; this is the remains of the Foramen Ovale of the foetus; and in many adult subjects a probe may be passed through the superior part of the fossa ob- liquely into the left auricle. The Valvula Nobius, or Eustachian Valve, is a membrane-like duplicature of the inner coat of the auricle, observed where the vena cava inferior is continued into the auricle, and stretching from that vein towards the opening into the right ven- tricle. This valve is sometimes found reticulated. Behind this valve is the orifice of the Coronary Vein, with its small valve. The Foramina Thebesii are minute orifices of veins, which open into all the cavities of the heart; they are most numerous, however, in the right auricle. The Ostium Venosum, or opening of the right auricle into the right ventricle, is somewhat oval; it has a valve which projects into the right ventricle. The Right Ventricle may now be opened by an incision, carried from the root of the pulmonary artery down to the apex of the heart. This incision should be made with care, lest the parts on the in- side of the ventricle be destroyed by it; it should pass along the right side of the septum ventriculorum, the situation of which is marked out by large branches of the coronary artery and vein. A small opening should first be made, into which one blade of the scissars can be introduced: the incision may be continued through 195 the apex of the heart, or a flap may be made by another cut, passing from the beginning of the first along the margin of the right auricle.—In this ventricle, observe (he projecting bundles of muscular fibres, the Tricus- pid Valves arising from the margin of the ostium ve- nosum, and projecting into the right ventricle. This valve forms a complete circle at its base, but has its edge divided into three parts, which are attached by tendinous filaments, named Chord ^Tendine^e, to the Carneje Columns, or muscular bundles of the ven- tricle. The Septum Ventriculorum, or partition of the two ventricles, is marked out externally by two veins running from the apex to the basis of the heart. Slit up the pulmonary artery ; observe how it arises from the back-part of the right ventricle, how smooth the inside of the ventricle becomes as it approaches the entrance of the artery, or ostium arteriosum. Ob- serve the three Semilunar or Sigmoid Valves. Their bases arise from the artery, their loose edges project into its cavity, and in the middle of the loose edge of each valve is seen a small white body, termed Corpus Sesamoideum Arantii. The artery is seen bifurcating into the right and left pulmonary arteries, and, just before its bifurcation, sending off to the aorta the ductus arteriosus, which in the adult is a liga- ment. The Left Auricle has four pulmonary veins opening into its cavity, which may be exposed by slit- ting up two of these veins. Observe that its coats are thicker than those of the right auricle. The septum auricularum, with the fossa ovalis, is here seen less 196 distinctly than on the right side. Observe also the os- tium venosum, opening into the left ventricle, and giv- ing attachment to the Valvula Mitralis. The Left Ventricle may be opened in the same manner as the right, by an incision carefully made in the left side of the septum or partition of the ventri- cles, and continued round the upper part of the ven- tricle, under the auricle. Observe the great thick- ness of the muscular coat; the Valvula Mitralis, forming two projections, which are attached by the chorda tendinea to the fleshy columns of this ven- tricle. Slit up the aorta; it has three semilunar valves, which resemble those of the pulmonary artery:—be- hind these valves the artery bulges out, forming the Sinuses of the aorta. Above two of the valves lie the orifices of the two coronary arteries, of which the left is the largest. 197 CHAP. IX. DISSECTION OF THE FACE. SECT. I. OF THE MUSCLES. UNDER the integuments of the face, there is al- ways a considerable quantity of adipose membrane; many of the muscles are very slender, and, lying em- bedded in this fat, require careful dissection. The whole side of the face is also supplied with numerous ramifications of the fascial nerve, or portio dura of the seventh pair. These nervous twigs are generally re- moved with the integuments. Twelve pair of muscles, and one single muscle, are described in this dissection. 1. The Orbicularis Palpebrarum—Arises, from the internal angular process of the frontal bone, and from a tendon at the inner angle of the eye, by a number of fleshy fibres which pass round the orbit, co- vering first the superior, and then the inferior eye-lid, and also the bony edges of the orbit. Inserted, by a short round tendon, into the nasal pro- cess of the superior maxillary bone. r 2 198 Situation: This muscle is intermixed, at its upper part, with the occipito-frontalis; it covers the upper part of the lacrymal sac. Use: To shut the eye, by bringing down the upper lid, and pulling up the lower; the fibres contracting to- wards the inner angle, as to a fixed point, compress the eye-ball and lacrymal gland, and convey the tears to- wards the puncta lacrymalia. Synonyma: Orbicularis palpebrarum et ciliaris ;— The ciliaris is only a part of the muscle covering the cartilages of the eye-lids, which are called the Cilia or Tarsi;—Maxillo-palpebral. 2. The Corrugator Supercilii—Arises, fleshy, from the internal angular process of the os frontis; it runs outwards and a little upwards, to be Inserted into the inferior fleshy part of the occipito- frontalis muscle, extending outwards as far as the mid- dle of the superciliary ridge. Situation: This muscle is concealed by the occipito- frontalis. It lies close to the upper and inner part of the orbicularis palpebrarum, with which it is con- nected. Use: To smooth the skin of the fore-head, by pull- ing it down after the action of the occipito-frontalis. When it acts more forcibly, it pulls down the eye- brow and skin of the fore-head, and produces vertical wrinkles. Synonyma: Musculus supercilii;—Musculus fronta- lis verus, seu corrugator;—Cutaneo-sourcillier. 3. The Compressor Naris—Arises, narrow, from the outer part of the ala nasi, and neighbouring part of the os maxillare superius. From this origin 199 a number of thin separate fibres run up obliquely along the cartilage of the nose toward the dorsum nasi, where the muscle joins its fellow, and is Inserted, slightly, into the lower part of the os nasi and nasal process of the superior maxillary bone. Situarion: It is superficial; its origin is connected with the levator labii superioris ateque nasi ; and its upper part with some of the descending fibres of the occipito-frontalis. Use: To compress the ala towards the septum nasi; but, if the fibres of the occipito-frontalis, which adhere to it, act, the upper part of this muscle assists in pulling the ala outwards: It also corrugates the skin of the nose. Synonyma: Transversalis seu myrtiformis;—Dila- tores alarum nasi ;---Constrictor nasi;---Maxillo-na- rinal. 4. Levator Labii Superioris Aljeque Nasi— Arises by two distinct origins ; the first Irom the nasal process of the superior maxillary bone, where it joins the os fronti, at the inner canthus of the eye ; it de- scends along the nasal process, and is inserted into the outer part of the ala nasi, and into the upper lip.—The second arisen, broad and fleshy, from the external orbi- tar process of the superior maxillary bone, immediately above the foramen infra-orbitarium ; it runs down, becoming narrower, and is inserted into the upper lip and orbicularis oris. Situation: The first portion is sometimes called Levator Labii superioris Alaque Nasi, and the se- cond Levator Labii Superioris Proprius. 1 heir ori- gins are partly covered by the orbicularis palpebra- 200 turn. They descend more outwardly than the ala nasi. Use: To raise the upper lip towards the orbit, and a little outwards ; the first portion will also draw the ala nasi upwards and outwards. Synonyma: Incisivus lateralis et pyramidalis ;—— Elevator labii superioris proprius ;---Maxillo-labii- nasal. The infra-orbitary artery, vein, and nerve, are seen emerging from the infra-orbitary foramen under this muscle. 5. Zygomaticus Minor—Arises from the upper prominent part of the os mala, and, descending oblique- ly downwards and forwards, is Inserted into the upper lip near the corner of the mouth. Situation : Its origin is covered by the orbicularis palpebrarum ; it has its course between the levator la- bii superioris alaque nasi and the zygomaticus major. Frequently the orbicularis palpebrarum sends down a slip of fibres to the upper lip, which slip runs between the zygomaticus minor and levator labii superioris alaque nasi. Use: To draw the corner of the mouth and upper lip obliquely upwards and outwards. Synonyma: Petit zygomata-labial. 6. Zygomaticus Major—Arises, fleshy, from the os mala, near the zygomatic suture. Inserted into the angle of the mouth, appearing to be lost in the depressor anguli oris, and orbicularis oris. Situation : Its origin is partially covered by the or- 201 Bicularis palpebrarum; it lies more outwardly than the zygomaticus minor. Use: To draw the corner of the mouth and under lip upwards and outwards. Synonyma : Zygomaticus ;—Grand zygomato-la- bial. 7. The Levator Anguli Oris—Arises, thin and fleshy, from a depression of the superior maxil- lary bone, betwixt the root of the socket of the first dens molaris, and the foramen infra-orbitarium. Inserted, narrower, into the angle of the mouth. Situation: It lies more outwardly thanjhe levator labii superioris alaque nasi; it is in part concealed by that muscle, by the zygomaticus minor, and part of the zygomaticus major. At its insertion it is particularly connected with the depressor anguli oris. Use : To draw the corner of the mouth upwards. Synonyma: Levator labiorum communis ;-Cam- nus;—Sus-maxillo-labial. 8. The Depressor Anguli O^is-Arises, broad and fleshy, from the lower edge of the infenor maxil- lary bone, at the side of the chin, and, gradually becom- ing narrower, is Inserted into the angle of the mouth. _ Situation: This muscle is firmly connected with the platysma myoides; at its insertion it is blended with the zygomaticus major and levator angul, oris. Use: To pull down the corner of the mouth. Synonyma: Depressor labiorum communis;-in, infnilaris;—Sous maxillo-labial. T The Ue»».or L»n I„»,...—<""«> fleshy and broad, from the s.de of the lower jaw, a 202 little above its lower edge; it runs obliquely upwards and inwards, and is Inserted into the edge of the under lip. Situation : This muscle, at its insertion, decussates with its fellow. It is in part covered by the depressor anguli oris. It forms the thick part of the chin, and has its fibres interwoven with fat. Use : To pull the under lip downwards. Synonyma : Depressor labii inferioris proprius ;— Quadratus;—Mentonier-labial. 10. The Buccinator—Arises, tendinous and fleshy, from the lower jaw, as far back as the root of the coro- noid process ; from the upper jaw, as far back as the pterygoid process of the sphenoid bone; it then con- tinues to arise from the alveolar processes of both jaws, as far forwards as the dentes cuspidati. The fibres run forwards, and are Inserted into the angle of the mouth. Situation: This muscle lies deep, adheres to the membrane that lines the mouth ; and a quantity of fat is always found between its fibres and the other muscles and integuments. It is partly concealed by the masse- ter, and by the muscles which pass to the angle of the mouth, as the levator and depressor anguli oris, and zygomaticus major. It is inserted behind these mus- cles. In the cheek it is connected with the platysma myoides. Use: To draw the angle of the mouth backwards and outwards, and to contract its cavity, by pressing the cheek inwards. Synonyma : Retractor anguli oris ;—Alveolo-maxil- laire. 203 The single muscle is the Orbicularis Oris.—It consists of two planes of semicircular fibres, which decussate at the angles of the mouth. These fibres are formed chiefly by the muscles which are inserted into the lips; they sur- round the mouth. The superior portion runs along the upper lip, the inferior portion along the under lip. Situation: It is connected and intermixed with the insertions of all the preceding muscles of the face. Some of the fibres are connected to the septum nasi, and are by Albinus termed Nasalis Labii Superioris. Use: To shut the mouth, by contracting and draw- ing both lips together. Synonyma: Sphincter labiorum;—Semi-orbicula- ris superior et inferior ;—Constrictor labiorum ;— Labial. 11. Depressor L\bii Superioris AL^qufi Nasi___Arisrs, thin and fleshy, from the os maxillare superius, where it forms the alveoli of the dentes inci- siva. and dens caninus ; thence it runs up under part of the levator labii superioris alaque nasi. Inserted into the upper lip and root of the ala nasi. Situation: It is concealed by the orbicularis oris and levator labii superioris alaque nasi. It may be discovered by inverting the upper lip, and dissecting on the side of the frenum which connects the lip to the gums. Use: To draw the upper lip and ala nasi downwards and backwards. Synonyma: Depressor ala nasi ;—Incisivus medi- us ;—Depressor labii superioris proprius;—Maxillo- alveoli-nasal. 204 12. The Levator Labii Inferioris—.^rz'sea from the lower jaw at the root of the alveolus of the lateral incisor. Inserted into the under lip and skin of the chin. Situation: Those two small muscles are found by the side of the frenum of the lower lip. They lie un- der the depressor labii inferioris. Use: To raise the under lip and skin of the chin. Synonyma : Levator menti;—Incisivus inferior ;— Elevator labii inferioris proprius;—Sous-maxillo-cu- tane. On the side of the face we observe two strong mus- cles, and two other muscles are concealed by the angle of the inferior maxilla. 1. The Masseter is divided into two portions, which decussate one another. The anterior portion arises, tendinous and fleshy, from the superior maxillary bone, where it joins the os mala; from the lower edge of the os mala, and from its zygomatic process. The strong fibres run obliquely downwards and backwards, and are inserted into the outer surface of the side of the lower jaw, extending as far back as its angle. The Posterior Portion arises, principally fleshy, from the inferior surface of the os mala, and of the whole of the zygomatic process, as far back as the tubercle before the socket for the condyle of the lower jaw. The fibres slant forwards, and are inserted, tendinous, into the outer surface of the coronoid process of the lower jaw. Situation: The anterior portion conceals almost the whole of the posterior portion. The greater part 205 of this muscle is superficial. Below, it is covered by the platysma myoides; and above, a small portion of it is concealed by tr.e origin of the zygomaticus ma- jor. Use: To pull the lower to the upper jaw, and to move it forwards and backwards. Synonyma: Zygomato-maxillaire. 2. Temporalis—Arises, fleshy, from a semicircu- lar ridge in the lower and lateral part of the parietal bone, from all the squamous portion of the temporal bone, from the external angular process of the os fron- tis, from the temporal process of the sphenoid bone, and from an aponeurosis which covers the muscle. From these different origins the fibres converge, de- scend under the bony jugum formed by the zygomatic processes of the temporal and cheek bones. Inserted, by a strong tendon, into the upper part of the coronoid process of the lower jaw, to wnich it ad- heres on every side, but more particularly its fore-part, where the insertion is continued down to near the last dens molaris. Situation: This muscle is of a semicircular shape. It is covered by a fascia or aponeurosis. This fascia adheres to the bones which give origin to the upper part of the muscle, and, descending over it, is inserted into the jugum, and adjoining part of the os mala and os frontis. The temporalis, at its origin, lies under the expanded tendon of the occipito-frontalis, and under the small tendons which move the external ear. Its in- sertion is concealed by the jugum and by the mas- 206 seter; so that, to expose it, the masseter must be cut away. Use: To pull the lower jaw upwards, and press it against the upper. Synonyma: Crotaphites;---Arcadi-temporo-maxil- laire. In order to expose the following muscles, we must remove the muscles of the cheek and jaw, the masseter and insertion of the temporalis must be taken away, and the coronoid process of the inferior maxilla remov- ed by a saw. 3. The Pterygoideus Externus—Arises, from the outer side of the external plate of the pterygoid pro- cess of the sphenoid bone, from part of the tuberosity of the os maxillare adjoining to it, and from the root of the temporal process of the sphenoid bone. It passes backwards and outwards, to be Inserted into a depression in the neck of the con- dyloid process of the lower jaw, and into the anterior and inner part of the ligament of the articulation of that bone. Situation: This muscle passes almost transversely from the skull to its insertion. It is concealed by the muscles of the face and neck, and by the ascending pro- cesses of the lower jaw. Use: When this pair of muscles act together, they bring the jaw horizontally forwards. 'When they act singly, the jaw is moved forwards, and to the opposite side. Synonyma: Pterygoideus minor;---Pterigo-colli- maxillaire. 207 4. The Pterygoideus Internus—Arises, tendi- nous and fleshy, from the inner and upper part of the internal plate of the pterygoid process of the sphenoid bone, filling all the space between the two plates; and from the pterygoid process of the os palati between these plates. Inserted, by tendinous and fleshy fibres, into the in- side of the angle of the lower jaw. Situation: To expose this muscle, the jaw must be removed from its articulating cavity, and then pulled forwards, and toward the opposite side; or it may be sawn across at its sympyhsis, and the .other half re- moved. It is larger than the pterygoideus externus; and betwixt the two muscles there is a considerable quantity of cellular membrane, and the trunk of the in- ferior maxillary and gustatory nerves. Like that mus- cle, it is concealed by the lower jaw and facial muscles. Along its posterior edge we observe the Ligamentum Laterale Maxilla Inferioris, a ligamentous band, which extends from the back-part of the styloid process to the angle of the lower jaw. Use: To chaw the jaw upwards, and obliquely to- wards the opposite side. Synonyma : Pterygoideus major;—Pterigo-anguli- maxillaire. On the side of the face is situated a considerable sa- livary gland, the Parotid Gland, a large white mass, irregularly oblong and protuberant, filling up all the space betwixt the angle and ascending processes of the jaw, the mastoid processes, root of the cartilage of the ear, and zygomatic process of the temporal bone. From its anterior and upper part a white canal or duct 208 passes forwards over the masseter, and perforates the buccinator from without inwards, opening into the mouth opposite the first dens molaris. The coats of this duct are very thick and firm, consisting of a liga- mentous substance. SECT. II. OF THE VESSELS AND NERVES OF THE FACE. ARTERIES. The A. Maxillaris Externa,>the third branch of the carotid, comes from the neck over the lower jaw at the anterior edge of the masseter. It then runs under the depressor anguli oris, passes towards the angle of the mouth, and is often much contorted. Here it is named the A. Facialis or Angularis. It ascends by the side of the nose, and, reaching the inner angle of the eye, is lost on the muscles situated there, inosculating freely with the temporal, interna1 maxillary, and ophthalmic arteries. In this course it gives off many branches : I. Twigs to the masseter, depressor anguli oris, and chin; 2. A. Coronaria Labiorum. This artery is very much contorted.— At the angular commissure of the lips, it divides it- self into two branches, which run along the superior and inferior portions of the orbicularis oris, and join the same branches of the other side. 3. While the facial artery ascends by the side of the nose, it gives 209 off the external nasal arteries to the outside of the nose, and the A. Buccales to the cheek. The External Carotid is found ascending behind the parotid gland. It perforates the gland at its upper part, ascends over the zygomatic process immediately before the ear, and divides into the anterior, middle, and posterior temporal arteries, which ramify o er the side of the head, giving also branches to the forehead and occiput. But the carotid, while it lies embedded under the pa- rotid, sends several twigs to the substance of that gland, _and a considerable artery which passes forwards, and, ramifying on the side of the face, is named A. Trans- versalis Faciei. At this point also, the carotid sends off a large artery, the A. Maxillaris Interna. As many branches of this artery are met with in the dissec- tion of the face, it is proper to give a view of its distri- bution. The Internal Maxillary passes behind the condyloid process of the lower jaw : it directs its course towards the bottom of the orbit of the eye ; and it is at this point that it sends off its numerous branches. (1.) Arteria Media Dura. M/itris (or Meningea spheno-spinalis or spinosa) passes through the spinal hole of the sphe- noid bone into the cranium, and is distributed to the dura mater. (2.) A. Maxillaris Inferior, vel Dentalis Inferior, runs downwards, enters the foramen at the root of the ascending processes of the lower jaw ; then passes through the canal of the lower jaw, supply- •n~ the teeth and sockets, and emerges by the foramen n,entale, to be distributed to the chin. It is accompa- s 'J 210 nied by a nerve and one or two veins. (5.) A. Ptery- goidea and A. Temporales Profunda, are small branches of the internal maxillary which pass to the pterygoid muscles, and to the inner part of the tempo- ral muscle. (4.) A. Pharyngea, branches to the pha- rynx, palate, and base of the skull. (5.) A. Alveolaris, which gives branches to the teeth of the upper jaw, and to the jaw-bone itself. (6.) A Branch through the fora- men spheno-palatinum to the nose ; andf(7.) An Artery through the palato-maxillary canal to the palate. The continued trunk of the internal maxillary enters the orbit by the spheno-maxillary slit. It sends off a branch which runs along the inner side of the orbit, and passes out at the inner canthus of the eye on the fore- head. The artery itself runs along the bottom of the orbit in a canal on the upper part of the great tubero- sity of the os maxillare superius, and emerges by the foramen infra-orbitarium on the face; hence it is termed A. Infra-Orbitaria, and is distributed to the cheek and side of the nose. The Frontal Artery is also seen in the dissection of the face, passing from the orbit through the foramen supra-orbitarium to be distributed to the forehead. This artery is sent off from the ophthalmic artery, which is a branch of the internal carotid. If the face be injected, a remarkable anastomosis of arteries will be observed at the inner angle of the eye. 211 VEINS. The veins of the face are numerous, and pass into^the external and internal jugular veins. NERVES. 1. The Portio Dura of the seventh pair, Nervus Communicans Faciei, or Facial Nerve, after its course through the temporal bone in the aqueduct of Fallopius, Comes out by the foramen stylo-mastoideum. It imme- diately gives off branches to the neighbouring parts, as behind the ear. It then passes through the substance of the parotid gland, and emerges on the face in three great branches, which have frequent mutual communi- cations : this division of the nerve is called Pes Anse- rinus. (I.) The ascending branch ramifies on the temple and forehead. (2.) The middle branch sends its ramifications over the side of the face, the proper Facial Nerves. (3.) The descending branch sends its twigs along the chin, down upon the neck, and backwards upon the occiput. (2.) The Superior Cervical Nerves send off several branches, which ramify on the side of the face and head, and communicate freely with the branches of the portio dura. As, in the course of this dissection, we meet with many twigs of the second and third branches of the fifth pair of nerves, it will be advisable here to describe these nerves. 212 3. Nervus Maxillaris Superior, or Second Branch of the Fifth Pair. The superior maxillary nerve, having left the cranium by the foramen rotun- dum of the sphenoid bone, emerges behind the antrum maxillare, at the lower back part of the orbit, and at the root of the pterygoid process of the sphenoid bone. It immediately sends out branches: 1. A small branch which passes through the spheno-maxillary slit to the periosteum and fat of the orbit. 2. The largest branch is the Infra-Orbitary Nerve. It enters the chan- nel in the top of the antrum maxillare, accompanying the infra-orbitary artery, comes out at the foramen infra-orbitarium, and is widely distributed to the cheek, under lip, and outside of the nose, communicating with ramifications of the portio dura. 3. Branches to the temporal muscle, os mala, Sec. 4. Other branches form a small ganglion at the root of the orbit, which sends twigs, named the superior Nasal Nerves, through the foramen spheno-palatinum to the nose. 5. The Vidian Nerve, which enters the foramen pterygoi- deum, and passes again into the cranium, to connect itself with the portio dura. 6. The Palatine Nerve, which runs through the palato-maxillary canal to the palate. 7. Twigs which supply the gums and alveoli of the upper jaw. 4. Nervus Maxillaris Inferior, or Third Branch of the Fifth Pair. The inferior maxillary nerve leaves the cranium by the foramen ovale of the sphenoid bone. It has its course downwards and out- wards ; and,.having given twigs to the parts near which it passes, as the masseter, pterygoid, and tem- 213 poral muscles, it divides at the angle of the lower jaw into two branches. 1. The Nervus Dentalis Inferior enters the foramen at the angle of the lower jaw ; ac- companies the inferior dental artery along the canal in that bone, giving nerves to the teeth; emerges by the foramen mentale, and is distributed to the chin. 2. The Nervus Gustatorius, vel Lingualis, passes to the tongue. It was seen in the dissection of the neck lying elose upon the lower jaw-bone, below the inferior edge of the pterygoideus internus, and above the superior fibres of the mylo-hyoideus. It supplies the substance of the tongue, and the salivary glands situated at the root of the tongue. This nerve receives the chorda tympani, a small twig which comes from the seventh pair through the slit in the articulating cavity of the temporal bone. 5. In the dissection of the face, we also meet with the Frontal Nerve, which comes from the first branch of the fifth pair, and which is seen accompany- ing the frontal artery through the foramen supra-orbi- tarium. It is distributed to the fore-head. 214 CHAP. X. DISSECTION OF THE THROAT ON looking into the mouth, we observe a soft cur- tain hanging from the palate bones, named the Velum Pendulum Palati, or Soft Palate. The apex of the velum forms a small projecting glandular body, termed the Uvula, or pap of the throat. From each side of the Uvula, two muscular half-arches or columns are sent down, the anterior to the root of the tongue, the posterior to the side of the pharynx. Between these half-arches on each side, are situated the glands termed Amygdala, or Tonsils. The common opening behind the anterior arch is named the Fauces, or Top of the Throat, from which there are six passages, two upwards, being one to each nostril, called the Posterior Nostrils ; two at the sides, called Eustachian Tubes, passing on each side to the ear*; two downwards, of which the ante- rior is the passage through the glottis and larynx into the * A probe may be introduced through the anterior nostrils into the Eustachian tube ; the tube opens into the pharynx in a direc- tion opposite to the space between the roots of the middle and inferior turbinated bones. 215 trachea * the posterior, which is the largest, is the pharynx, or top of the oesophagus, and leads to the stomach. SECT. I. MUSCLES SITUATED ABOUT THE ENTRY OF THl FAUCES. These consist of four pairs, and a single muscle in the middle. 1. Constrictor Isthmi Faucium—Arises, by a slender beginning, from the side of the tongue, near its root; thence running upwards within the anterior arch, before the amygdala, it is Inserted into the middle of the velum pendulum palati, as far as the root of the uvula. It is here con- nected with its fellow, and with the beginning of the palato-pharyngeus. Situation: It forms the anterior half-arch. Use: To draw the velum towards the root of the tongue, which at the same time it raises, and, with its fellow, to contract the opening into the fauces. Synonyma : Glosso-staphylinus. 2. The Palato-Pharyngeus--Arises, by a broad beginning, from the root of the uvula in the middle of the velum pendulum palati, and from the tendinous expansion of the circumflexus palati. The 216 fibres pass along the posterior arch behind the amyg- dala, and run backwards to the superior and lateral part of the pharynx, where they are scattered, and mixed with those of the stylo-pharyngeus. Inserted into the edge of the upper and back part of the thyroid cartilage, and into the back part of the pharynx. Situation: It forms the posterior half-arch or co- lumn. Use: To draw the uvula and velum downwards and backwards, and pull the thyroid cartilage and pha- rynx upwards; to shut the passage into the nostrils, and, in swallowing, to thrust the food from the fauces into the pharynx. Synonyma : Thyro-staphylinus;—Thyreo-pharyngo- staphylinus ;—Palato-pharyngien. The Salpingo-Pharyngeus of Albinusis composed of a few fibres of this muscle, which arise from the an- terior and lower part of the cartilaginous extremity of the Eustachian tube, and are inserted into the inner part of the last-mentioned muscle. 3. The Circumflexus, or Tensor Palati,—Arises, from the spinous process of the sphenoid bone, behind the foramen ovale, and from the Eustachian tube near it3 osseous part; runs down along the pterygoideus internus, and forms a round tendon, which passes over the hook of the internal plate of the pterygoid process of the sphenoid bone, and soon spreads into a broad ten- dinous expansion. Inserted into the velum pendulum palati, and semi- lunar edge of the os palati. 217 Situation: Its insertion extends as far as the suture which joins the two dssa palati. Some of its posterior fibres generally join with the constrictor pharyngis su- perior and palato-pharyngeus. Use: To stretch the velum, to draw it downwards, and to one side. Synonyma : Spheno-salpingo-staphylinus, seu Staphy- linus externus;— Musculus tuba novus, vel Fa^ato- salpingeus;—Pterygo-staphylinus;---Spheno-suipingo- staphilin. 4. The Levator Palati—Arises, tendinous and fleshy, from the extremity of the petrous portion of the temporal bone, and from the Eustachian tube. Inserted into the whole length of the velum pendu- lum palati, as far as the root of the uvula, uniting with its fellow. Use: To draw the velum upwards and backwards, so as to shut the passage from the fauces into the mouth and nose. Synonyma: Levator palati mollis;—Petro-salpingo- staphylinus, vel Salpingo-staphylinus internus;—Sal- pingo-staphylinus Valsalva, vel Pterygo-staphylinus externus;—Spheno-staphy iinus;---Petro-salpingo-sta- philin. The single muscle is the Azygos Uvula;.—It arises, fleshy, from the ex- tremity of the sutare which unites the ossa palati; runs down the whole length of the velum, like a small earth-worm, adhering to the tendons of the circumflex! palati. Inserted into the tip of the uvula. T 218 Use: To raise the uvula upwards and forwards, and shorten it. Synonyma: Staphylinus, or Epistaphylinus;—Palato- staphylinus. SECT. II. MUSCLES SITUATED ON THE POSTERIOR PART OJ THE PHARYNX. Of these there are three pair. 1. The Constrictor Pharyngis Inferior. This muscle arises, from the outside of the ala of the thyroid cartilage, near the attachment of the thyreo-hyoideus muscle, and from the side of the cricoid cartilage, near the crico-thyroideus. Inserted into the white line on the back-part of the pharynx, where it is united to its fellow. Situation: This muscle covers the under part of the middle constrictor; the superior fibres run obliquely upwards, while the inferior fibres have a transverse di- rection. Use: To compress that part of the pharynx which it covers, and to raise it with the larynx a little up- wards. Synonyma: Thyro-pharyngeus and crico-pharynge- us;—Crico-thyro-pharyngien. 2. The Constrictor Pharyngis Medius--- prises from the superior edge of the cornu of the os 219 hyoides, extending as far forwards as the graniform process, or appendix; and from the ligament which connects it to the thyroid cartilage. The superior fibres ascend obliquely, the others run more trans- versely. Inserted into the cuneiform process of the os occipi- tis, before the foramen magnum, and into a white line in the middle of the posterior surface of the pharynx, where it is joined to its fellow. Situation : The lower part of this muscle is covered by the muscle last described, while the upper part co- vers the inferior fibres of the constrictor superior. Use: To compress that part of the pharynx which it invests, and to draw it and the os hyoides upwards. Synonyma: Hyo-pharyngeus, and Chondro-pharyn- geus;—Hyo-glosso-basi-pharyngien. 3. Constrictor Pharyngis Superior—Arises, above, from the cuneiform process of the os occipitis, before the foramen magnum; lower down from the pte- rygoid process of the sphenoid bone; from the upper and under jaw, near the alveolar processes of the last dentes molares ; and from the back-part of the buccina- tor muscle. Some fibres also come from the root of the tongue, and from the palate. Inserted into a white line in the middle of the poste- rior surface of the pharynx. - Situation: The larger part of this muscle is covered by the constrictor medius. Use: To compress the upper part of the pharynx, and draw it forwards and upwards. 220 Synonyma: Cephalo-pharyngeus, Pterygo-pharynge- us, mylo-pharyngeus, and glosso-pharyngeus;—Pteri- go-syndesmo-staphili-pharyngien. SECT. III. MUSCLES OF THE LARYNX. The Larynx is composed of five Cartilages: l.The Thyroid Cartilage, situated immediately below the os hyoides in the middle of the throat. 2. The Cricoid Cartilage, situated immediately below the thyroid cartilage, betwixt it and the superior rings of the trachea. 3. The Epiglottis, a broad triangular cartilage, very elastic, situated behind the root of the tongue, and covering the entrance into the upper part of the larynx. 4 Sc 5. The arytenoid cartilages, two small bodies, like peas, situated behind the thyroid cartilage, on the upper edge of the back-part of the cricoid cartilage, and between the two ala or wings of the thyroid cartilage. These two small cartilages form betwixt themselves and the thyroid a longitudinal fis- sure, extending from before backwards, which is called the Glottis, or Rima Glottidis, and leads to the tra- chea. The muscles situated about the glottis consist of four pair of small muscles, and a single one. I. The Crico-Aryt^noideusPosticus—Arises, fleshy, from the posterior part of the cricoid cartilage, and is 221 Inserted, narrow, into the back-part of the arytenoid cartilage of the same side. Use: To open the rima glottidis a little, and, by pull- ing back the arytenoid cartilage, to render the ligament of the glottis tense. Synonyma: Crico-creti-arithenoidien. 2. The Crico-AryTjenoideus Lateralis-- Arises, fleshy, from the side of the cricoid cartilage, where it is covered by the ala of the thyroid carti- lage. Inserted into the outer side of the arytenoid carti- lage. Situation: It lies more forward than the last-de- scribed muscle. Use: To open the rima glottidis, by pulling the liga- ments from each other. Synonyma: Crico-lateri-arithenoidien. 3. The Thyreo-Aryt-snoideus—Arises from the middle and inferior part of the posterior surface of the thyroid cartilage ; runs backwards, and a little upwards, and is Inserted into the fore-part of the arytenoid carti- lage. Situation : It is situated more forwards than the mus- cle last described. Use: To pull the arytenoid cartilage forwards, and thus shorten the ligament of the larynx or glottis. Aryt.enoideus Obliquus—Arises from the base of one arytenoid cartilage; and, crossing its fellow, is Inserted into the tip of the other arytenoid carti- lage. T 2 222 Use: When both act, they pull the arytenoid carti- lages towards each other. Synonyma: Arytanoideus minor. The single muscle is the ARYT-ENoiD-ffius Transversus, which arises from the whole length of one arytenoid cartilage, and passes across, to be Inserted into the whole length of the other arytenoid cartilage. Situation: It is situated anterior to the arytanoidei obliqui. Use: To shut the rima glottidis, by bringing the arytenoid cartilages together. On each side of the larynx, there are also a few mus- cular fibres, which are named as follows. 1. Thyreo-Epiglottideus—Arising, by a few pale separated fibres, from the thyroid cartilage, and Inserted into the epiglottis laterally. Use: To draw the epiglottis obliquely downwards, or, when both muscles act, directly downwards; and at the same time to expand it. 2. The Aryt^no-Epiglottideus—Arises, by a few slender fibres, from the lateral and upper part of the arytenoid cartilage, and is Inserted into the epiglottis, along with the former muscle. Use: When both muscles act, to pull the epiglottis close upon the glottis. 223 CHAP. XI. DISSECTION OF THE ORBIT OF THE EYE. THE globe or ball of the eye is situated about the middle of the orbit. It is connected to the bone by its muscles, and by the optic nerve; and all these parts are embedded posteriorly in a soft, fatty substance, which fills up the bottom of the orbit.—The tunica, or mem- brana conjunctiva, is seen lining the inner surface of the eye-lids, and reflected from them over the anterior part of the globe of the eye, so that the back-part of the eye-ball, and all the muscles and nerves, are situated be- hind it. This membrane must therefore be dissected away, the upper part of the orbit, which is formed by the os frontis, removed with a saw, and the fat sur- rounding the muscles, vessels, and nerves, cautiously dissected away with the scissars. SECT. I. MUSCLES situated within the orbit. Seven muscles are contained within the orbit, of which one belongs to the upper eye-lid, and six to the globe of the eye. 224 l. The Levator Palpebrje Superioris—Arises, by a small tendon, from the upper part of the foramen opticum of the sphenoid bone; the tendon forms a broad flat belly. Interted, by a broad thin tendon, into the upper eye- lid, adhering to the tarsal cartilage, which gives form to the eye-lid. Use: To open the eye, by drawing the superior eye- lid upwards. Synonyma: Aperiens palpebram rectus;—Orbito- sus-palpebral. There are four straight muscles, or recti, belong- ing to the globe of the eye. These four muscles re- semble each other, all arising by narrow tendons from the margin of the foramen opticum, where they sur- round the optic nerve; all forming strong fleshy bel- lies, and inserted, by broad, thin tendons, at the fore- part of the globe of the eye, into the tunica sclerotica, or outer tunic of the eye, and under the tunica con- junctiva. 2. The Levator Oculi—Arises, by a narrow ten- don, from the upper part of the foramen opticum of the sphenoid bone; it forms a fleshy belly, and is Inserted into the superior and anterior part of the tunica sclerotica, by a broad thin tendon. Situation: It lies below the levator palpebra supe- rioris. Use: To raise the globe of the eye. Synonyma: Elevator;—Rectus attollens oculi;— Sus-optico-spheni-scleroticien. 3. The Depressor Oculi—Arises from the infe- rior margin of the foramen opticum, and is 225 Inserted into the inferior and anterior part of the tu- nica sclerotica. Use: To move the globe of the eye downwards. Synonyma : Rectus deprimens oculi;—sous-opti- spheno-scleroticien. 4. The Adductor Oculi—Arises from the inner part of the foramen opticum, and is Inserted into the inner and anterior part of the tunica sclerotica. It is the shortest of the four recti muscles. Use: To draw the eye towards the nose. Synonyma: Rectus adducens oculi;—Orbito-intus- scleroticien. 5. The Abductor Oculi—Arises from the outer part of the foramen opticum. Inserted into the outer part of the tunica sclerotica. It is the longest of the recti. Use: To move the globe outwards. Synonyma: Rectus abducens oculi;—Orbito-extus- scleroticien. The two next are oblique muscles. 6. The Obliquus Superior, or Trochlearis,— Arises, by a small tendon, from the margin of the foramen opticum, between the levator and abductor oculi. Its lon^ slender belly runs along the inner side of the orbit to the internal angular process of the os frontis, where a cartilaginous pulley is fixed. The muscle then forms a tendon, which passes through the pulley, runs obliquely downwards and outwards, in- closed in a membranous sheath; and becoming broader and thinner, is Inserted into the tunica sclerotica, about half-way 226 between the insertion of the levator oculi, and the en- trance of the optic nerve. Use: To roll the globe of the eye, and turn the pu- pil downwards and outwards. Synonyma: Obliquus major ;—Optico-trochlei-scle- roticien. 7. The Obliquus Inferior—Arises, narrow, and principally tendinous, from the outer edge of the orbitar process of the superior maxillary bone, near its junction with the os unguis. It runs obliquely outwards and backwards, under the depressor oculi, and is Inserted, by a broad thin tendon, into the sclerotica, between the entrance of the optic nerve, and the inser- tion of the abductor oculi. Use: To draw the globe of the eye forwards, in- wards, and downwards, and to turn the pupil up- wards. Synonyma: Obliquus minor;—Maxillo-scleroticien. In the orbit, we also meet with the Lachrymal Gland.—This gland is of a yellowish colour ; it is si- tuated in a depression of the os frontis near the temple. It adheres closely to the fat which surrounds the mus- cles and posterior convexity of the eye. It sends off se- veral small ducts which pierce the tunica conjunctiva lining the upper eye-lid; these ducts cannot be seen, . unless the part be macerated in water, when they are filled with the liquid. The Puncta Lachrymalia are two small holes near the internal angle of the palpebra, situated one in each eye-lid. They lead into the Lachrymal 227 Sac This sac is an oblong membranous bag, situat- ed at the inner angle of the eye, in a depression formed by the os unguis, and nasal process of the su- perior maxillary bone. It receives the tears by the puncta lachrymalia, and from the sac they are con- « veyed into the nose by a Duct, named the Lach- rymal, or Nasal. The lower extremity of this duct opens into the nose on one side of the antrum maxillare, and under the os spongiosum inferius. A probe, with its extremity bent, may be introduced from the nose through this duct into the lachrymal sac. The Caruncula Lachrymalis is a small reddish gra- nulated body, situated at the internal angle of the pal- pebra. SECT. II. OF THE VESSELS AND NERVES MET WITH IN THE ORBIT OF THE EYE. ARTERIES. The Ophthalmic, or Ocular Artery, is a branch of the internal carotid. It enters the orbit from the basis of the cranium by the foramen opti- cum. It gives branches to the lachrymal gland, fat, muscles, and globe of the eye. One twig, named the A. Centralis Retina, enters the substance of the optic nerve, and is continued on to the retina;— 228 twigs also pass to the eye-lids, and to the inner an- gle of the eye. The Arteria Frontalis is a branch of this artery; it is seen running towards the supra- orbitary notch or foramen, and is distributed to the forehead. The Infra-Orbitary Artery is found in the lower part of the orbit; it is the continued trunk of the internal maxillary, entering the orbit by the sphe- nomaxillary slit. It is seen passing along the canal in the upper part of the great tuberosity of the os max- illare superius, and emerges on the face by the infra- erbitary hole. veins. These correspond with the arteries ; they discharge their blood partly into the branches of the external ju- gular vein near the forehead and temples, and partly into the internal jugular. NERVES. 1. The Optic Nerve is seen coming through the foramen opticum, and entering the back part of the globe of the eye, to form the retina. 2. The Nerve of the Third.Pair, Motor Oculi, having entered the orbit through the superior orbi- tary fissure, or foramen lacerum, is divided into four branches. (1.) The first runs upwards, and subdivides into two nerves, of which one supplies the levator oculi, and the other the levator palpebra superioris. (2.)The second branch goes to the depressor oculi, and is short. 229 ^3.) The third branch supplies the obliquus inferior, and also gives off a twig, which assists in forming the lenticular ganglion. (4.) The fourth branch supplies the adductor oculi. 3. The Nerve of the Fourth Pair, N. Patheticus, or Trochlearis, enters the orbit by the superior orbitary fissure, and runs to the obliquus superior. 4. The first branch of the Nerve of the Fifth Pair, named Ophthalmic, or Orbitary, enters the orbit by the superior orbitary fissure, and divides into three branches. (1.) The Frontal, Supra-orbitary, or Superciliary Nerve, accompanies the frontal artery along the upper part of the orbit, close to the bone; and having passed through the supra-orbitary notch, is distributed to the forehead. (2.) The Nasal Nerve, or inner branch, runs to- wards the nose, and is distributed to th'e inner side of the- orbit, and to the nose. (3.) The Temporal or Lachrymal Branch supplies the lachrymal gland, and the parts at the outer side of the orbit. The Lenticular Ganglion is a small ganglion, situated within the orbit, formed by short branches of the ophthalmic nerve, and by a twig of the third pair. It sends off delicate nerves, which run along the sides of the optic nerve, and pierce the coats of the eye. 5. The second branch of the Fifth Pair, called the Superior Maxillary Nerve, sends off a branch through the bony canal in the bottom of the orbit. This is 230 is the Infra-orbitary Nerve. It accompanies the artery of the same name, and emerges on the face by the infra-orbitary hole. 6. The Trunk of the Sixth Pair of Nerves passes through the superior orbitary fissure to th e abductor oculi. These delicate nerves are surrounded by the adipose substance found in the orbit, and require to be dissected with the utmost care. CHAP. XII. DISSECTION OF THE MUSCLES SITUATED ON THE POSTERIOR PART OF THE TRUNK AND NECK. FROM the number and intimate connection of these muscles, their description necessarily is complicated, and their dissection difficult. The smaller muscles, in- deed, cannot be separated, without dividing some of their fibres. We do not here, as in the limbs, find the muscles distinctly marked, loosely connected by cellu- lar membrane, and separated with facility ; but closely united, and in many places having their fibres so in- termixed, as to render their divisions indistinct and un- 231 • In this dissection we meet with twenty-two distinct pair of muscles, besides a number of small muscles situated between the processes of contiguous vertebra. On removing the integuments of the posterior part of the neok and back, we expose, 1. The Trapezius.—It arises, by a thick round tendon, from the lower part of the protuberance in the middle of the os occipitis behind, and, by a thin tendi- nous expansion, from the superior transverse ridge of that bone ; from the five superior cervical spinous pro- cesses by the ligamentum nucha ; tendinous, from the two inferior cervical spinous processes, and from the spinous processes of all the vertebra of the back. The fleshy fibres coming from the neck descend obliquely, while those from the back ascend. Inserted, fleshy, into the posterior third part of the clavicle ; tendinous and fleshy, into the acromion, and into the upper edge of all the spine of the scapula. The fibres slide over a triangular surface at the extremity of the spine of that bone. Situation : This muscle is quite superficial, and con- ceals all the muscles situated in the posterior part of the neck, and upper part of the back. It adheres to its fellow the whole length of its origin. Its anterior fibres lie posterior to those of the sterno-mastoideus, but are not in contact with them, a considerable quantity of adipose substance being interposed. The posterior cervical ligament (ligamentum nucha vel colli) is a ligament which arises from the middle of the occipital bone, runs down on the back-part of the neck, adhering to the spinous processes of the cervical vertebra, and , 232 giving origin to the fibres of the trapezius, and of other muscles. Use: To move the scapula in different directions. The superior fibres draw it obliquely upwards, the mid- dle transverse ones draw it directly backwards, and the inferior fibres move it obliquely downwards and back- wards. Also, to draw back the head, and contribute fo its rotatory motions. Synonyma : Cucullaris ;---Occipiti-dorso-clavi-sus- acromien. It should be reflected from the spine and head. 2. The Latissimus Dorsi—Arises, by a broad thin tendon, from all the spinous processes of the os sacrum, and of the lumbar vertebra ; from the spinous processes of the seven inferior dorsal vertebra ; from the poste- rior part of the spine of the os ilium; also from the extremities of the four inferior false ribs, by four dis- tinct fleshy digitations, which intermix with those of ♦the obliquus externus abdominis. The inferior fleshy fibres ascend obliquely; the superior run transversely: they pass over the inferior angle of the scapula (from which the muscle often receives a thin fasciculus of fibres), to reach the axilla, where they are all collected and twisted. Inserted, by a strong flat tendon, into the inner edge of the groove in the os humeri, which receives the long tendon of the biceps flexor cubiti. Situation: Where this muscle arises from the dor- sal vertebra, it is concealed by the origin of the tra- pezius. The remainder of it is placed immediately under the skin, and covers the deeper seated mus> 233 cles of the loins and back. It is situated superior to the gluteus maximus, and posterior to the obliquus ex- ternus abdominis. Its insertion cannot be traced till the muscles of the arm are dissected; it forms the" fold on the posterior part of the hollow of the arm-pit. The tendon of this muscle, with the subjacent tendon of the serratus posticus inferior, assists in forming the fascia lumborum. Use: To pull the arm backwards and downwards, and to roll the os humeri. It should be reflected from the spine, pelvis, and ribs. Synonyma: Ani-scalptor;—Dorsi-lumbo-sacro-hume- ral. Remove the trapezius and latissimus dorsi, and two muscles will be seen passing from the neck to the sca- pula. 3. The Rhomboideus. This muscle is divided inta two portions. (1.) Rhomboideus major (the inferior portion) arises, tendinous, from the spinous processes of the four or five superior dorsal vertebra. Inserted into all the base of the scapula below its spine, extending as far as its inferior angle. (2.) Rhomboideus Minor (the superior portion) arises, tendinous, from the spinous processes of the three inferior vertebra of the neck, and from the liga- mentum nucha. Inserted into the base of the scapula, opposite to the triangular plain surface at the root of the spine. Situation: This muscle lies beneath the trapezius i\nd latissimus dorsi; a small part of the rhomboideus U 2 234 major may be seen between these muscles, and the in* ferior part of the base of the scapula. Use: To draw the scapula obliquely upwards, and di- rectly backwards. Synonyma: Cervici-dorso-scapulaire. The rhomboidei should be reflected from the spine. 4. The Levator Scapulae—Arises from the trans- verse processes of the five superior vertebra of the neck, by five distinct, tendinous, and fleshy slips, which unite and form a considerable muscle. Inserted, tendinous and fleshy, into the base of the scapula, above the root of the spine, and under the supe- rior angfo(not into the angle itself, as it is usually des- cribed). Situation: This muscle is concealed by the trapezi- us and sterno-mastoideus ; but a small part of its belly may be seen in the space between the edges of these muscles. The origin of the levator scapula is partly concealed by the splenius capitis; and the digitations, where they arise from the transverse processes, lie be- twixt similar attachments of the scaleni muscles before, and of the splenius colli behind. Use: To draw the scapula upwards, and a little for- wards. Synonyma: Elevator, seu Musculus Patientia;—An- gularis, vel Levator proprius;—Trachelo-anguli-scapu- laire. Detaching the rhomboideus from its origin in the spine, you will see another muscle passing from the whole of the basis of the scapula. 5. The Serratus Magnus-—Arises, by nine fleshy digitations, from the nine superior ribs. These digitations are seen on the anterior part of the thorax; they pass obliquely backwards, and form a strong fleshy muscle. Inserted, principally fleshy, into the whole of the base of the scapula. Situation: This muscle lies between the scapula and the ribs, so that, to see its course, the articula- tion of the clavicle to the sternum should be divided, and the scapula lifted from the trunk. It is concealed by the latissimus dorsi, by the two pectoral muscles, and the scapula. The only part of it which can be seen before the removal of those muscles, projects betwixt and below them on the side of the trunk. The lower digitations, which pass more anteriorly than the edge of the latissimus dorsi, are intermixed with the superior digitations of the obliquus externus abdominis. The superior digitations arise behind the pectoralis minor. The insertion of the muscle is be- tween the subscapularis, which arises from the inter- nal surface of the scapula, and the insertions of the rhomboideus and levator scapula. Use : To move the scapula forwards, and, when the scapula is forcibly raised, to draw the ribs up- wards. Synonyma: Serratus major anticus;—Costo-basi- scapulaire*. The removal of the rhomboideus also exposes, " 6. The Serratus Superior Posticus. This muscle arises, by a thin broad tendon, from the spinous • The upper extremity may now be removed from the trunk. 236 processes of the three inferior cervical vertebra, and of the two superior dorsal. Inserted, by distinct fleshy slips, into the second, third, fourth, and sometimes the fifth ribs, a little be- yond their angle. Situation: This muscle is concealed by the rhom- boideus and scapula, except a few of its superior fibres, which appear above the upper edge of the rhomboideus minor. It covers part of the origin of the splenius. I Use: To elevate the ribs, and dilate the thorax. Synonyma: Cervici dorso-costal. Reflect it from the spine. 7. The Splenius is divided into two portions: (1.) The Splenius Capitis—Arises, tendinous, from the spinous processes of the two superior dorsal, and five inferior cervical vertebra. It forms a flat broad muscle, which ascends obliquely, and is inserted, tendi- nous, into the posterior part of the mastoid process, and into a small part of the os occipitis, immediately below its superior transverse ridge. Situation: This muscle is covered by the trapezius, and by the insertion of the sterno-cleido-mastoideus, and a small part of it is seen on the side of the neck be- twixt those two muscles. The lower part of its origin is covered by the serratus superior posticus. Reflect it from the occiput. (2.) The Splenius Colli—-Arises, tendinous, from the spinous processes of the third, fourth, fifth, and sometimes the sixth dorsal vertebra. It forms a small fleshy belly, which ascends by the side of the verte- bra, and is inserted into the transverse processes of 237 the four or five superior cervical vertebra, by distinct tendons, which lie behind similar tendons of the levator scapula. Situation: This muscle is concealed by the serratus superior posticus, and splenius capitis. Use: To bring the head and upper vertebra of the neck obliquely backwards. When both muscles act,, they pull the head directly backwards. Synonyma: Cervici-dorsi-mastoidien, et dorso-trache- lien. Reflect it from the dorsal vertebrae. 8. The Serratus Posticus Inferior—Arises, by a broad thin tendon, from the spinous processes of the two or three inferior dorsal vertebra, and from the three superior lumbar spines by the fascia lum- borum. Inserted, by distinct fleshy slips, into the lower edges of the four inferior ribs, at a little distance from their cartilages. Situation: This is a thin muscle, of considerable breadth, situated at the lower part of the back, under the middle of the latissimus dorsi. Its tendon lies un- der that of the latissimus dorsi, but, although firmly ad- hering to it, is distinct, and may be separated by cau- tious dissection. Its insertion into the ribs is situated immediately behind the attachments connecting the la- tissimus dorsi to the ribs, which attachments must therefore lie behind the obliquus externus abdominis, and serratus posticus inferior. Use: To pull the ribs downwards and backwards. Synonyma: Dorso-lumbo-costal. Reflect it from the spine. 238 The Fascia Lumborum is now seen. It is a tendi- nous fascia, arising from the lumbar vertebra and os sacrum, giving origin to A.he lower part of the serra- tus posticus inferior, and to the posterior fibres of the obliquus internus and transversalis abdominis. It is also connected with the tendon of the latissimus dorsi. On detaching from the spine of this fascia, and the serratus posticus inferior, we expose a thick muscular mass, filling up all the space betwixt the spinous pro- cesses of the vertebra, and the angles of the ribs. This mass consists of three muscles: (I.) Sacro-Lumbalis on the outside, (2.) Longissimus Dorsi in the middle, (3.) Spinalis Dorsi close to the spinous processes. These three muscles are closely connected together; so that, to effect their separation, it is necessary to di- vide some of the fibres, 9 and 10. The Sacro-Lumbalis and Longissimus Dorsi—Arise, by one common origin, tendinous ex- ternally, and fleshy internally, from the spinous pro- cesses and posterior surface of the os sacrum ; from the posterior part of the spine of the os ilium, extending nearly as far forwards as the highest part of that bone when the body is erect; from the spinous processes, and from the roots of the transvere processes of all the lumbar vertebra. The thick fleshy belly, formed by this extensive ori- gin, ascends, and, opposite to the last rib, divides into the two muscles. The sacro-lumbalis is inserted into all the ribs near their angles, by long and thin tendons. The tendons 239 which pass to the superior ribs, are longer, ascend nearly straight, and are situated nearer to the spine than those tendons which pass to the lower ribs. On separating the inner edge of this muscle (£. e. the edge next to the spine) from the latissimus dorsi, and turn- ing the belly towards the ribs, we see six or eight small tendinous and fleshy bundles, which pass from the in- ner side of this muscle, to be inserted into the upper edge of the six or eight inferior ribs. These are called the Musculi Accessorii ad Sacro-Lumbalem. Use: To pull the ribs downwards, to assist in erect- ing the trunk of the body, and in turning it to one side. Synonyma: Lumbo-costo-trachelien. The longissimus dorsi is inserted into all the ribs except the two inferior, betwixt their tubercles and angles, by slips which are tendinous and fleshy, and into the transverse processes of all the dorsal verte- bra by small double tendons. The insertions in the ribs proceed from the outer side of the muscle, while the attachments to the transverse processes are seen on separating the longissimus dorsi from the spinalis dorsi. Use: To extend the veftebrse, and keep the body erect. Synonyma: Lumbo-dorso-trachelien. 11. The Spinalis Dorsi is much smaller than the two last-described muscles ; below, it cannot be separated from the longissimus dorsi, without divid- ing some fibres; it lies betwixt that muscle and the spine. 240 Arises, tendinous, from the spinous processes of the two superior lumbar vertebra, and of the three inferior dorsal. Inserted into the spinous processes of the nine up- per vertebra of the back, except the first, by as many distinct tendons. Uset: To extend the vertebra, and to assist in raising the spine. Synonyma: Lumbo-dorso-spinal. The three last-described muscles are covered below by the serratus posticus inferior and latissimus dorsi; above, by the rhomboideus, serratus superior posticus, and trapezius. 12. The Cervicalis Descendens—Arises from the upper edge of the four or five superior ribs, by as many distinct tendons, which lie on the inside of the tendinous insertions of the sacro-lumbalis. It forms a small belly, which ascends upwards, and is Inserted, by three distinct tendons, into the fourth, fifth, and sixth cervical vertebra. Situation: This muscle is small, it is frequently de- scribed as an appendage to the sacro-lumbalis. It arises between the sacro-lumbalis and longissimus dorsi, and is inserted into the transverse processes between the splenius colli and levator scapula; of course it is con- cealed by the rhomboideus, &c. It often receives a fleshy slip from the upper part of the longissimus dorsi. Use: To turn the neck obliquely backwards. , Synonyma: Transversalis collateralis colli. 13, The Transversalis Colli---Arises from the transverse processes of the five superior dorsal 241 vertebra, by five tendinous and fleshy slips, and is Inserted, tendinous, into the transverse processes of the five or six inferior cervical vertebra. Situation: The origin of this muscle lies on the in- side of the longissimus dorsi, and is sometimes consider- ed as an appendage to it. The insertion is situated between the cervicalis descendens and trachelo-mastoi- deus. Use: To turn the neck obliquely backwards, and a little to one side. Synonyma : Transversalis cervicis;—Transversalis colli major. 14. The Trachelo-Mastoideus lies nearer to the bone than the last-described muscle. Arises from the transverse processes of the three up- permost vertebra of the back, and of the five inferior of the neck, by as many thin tendons, which unite and form a fleshy belly. Inserted, tendinous, into the posterior surface of the mastoid process. Situation: This muscle lies on the outside of the complexus, and on the inside of the transversalis colli; its insertion is concealed by the splenius capitis; it is covered also by the levator scapula. Use: To keep the head and neck erect, and to draw the head backwards, and to one side. Synonyma: Trachelo-mastoideus, seu Capitis par tertiumFallopii;—Complexus minor, seu Mastoides lateralis. 15. The Complexus—Arises, by tendinous and fleshy fibres, from the transverse processes of the se- 242 ven Superior dorsal, and of the four or five inferior cer- vical vertebrae. It forms a thick, tendinous, and fleshy belly. Inserted, tendinous and fleshy, into the hollow be- twixt the two transverse ridges of the os occipitis, ex- tending from the middle protuberance of that bone, nearly as far as the mastoid process. Situation: This is a large muscle. Its origin from the cervical vertebrae is nearer to the spine than the trachelo-mastoideus, and it arises in the back nearer to the spine than the transversalis colli; it is covered by the splenius; but a large portion of it is seen be- tween the splenius and spine, immediately on removing the trapezius. Use: To draw the head backwards and to one side. Synonyma : Complexus, seu Biventer cervicis;— Complexus major;—Dorso-trachelo-occipital. On removing the complexus from the occiput, we find, close to the spine, 16. The Semi-Spinalis Colli.—It arises, by dis- tinct tendons, from the transverse processes of the six superior dorsal vertebrae, ascends obliquely close to the spine, and is Inserted into the spinous processes of all the verte- brae of the neck, except the first and the last. Situation: This muscle is situated close to the ver- tebrae at the posterior part of the neck and back. It arises on the outside of the semi-spinalis dorsi; its greater part is concealed by the complexus and lon- gissimus dorsi; and the part which projects between these muscles, is concealed by the serratus superior posticus. 243 Use: To extend the neck obliquely backwards. Synonyma: Spinalis cervicis;—Transverso-spinalis colli. 17. Semi-Spinalis Dorsi—Arises from the trans- verse processes of the seventh, eighth, and ninth ver- tebra of the back, by distinct tendons which soon grow fleshy. Inserted, by distinct tendons, into the spinous pro- cesses of the five superior dorsal vertebra, and of the two lower cervical. Situation: This muscle lies nearer the spine than the lower part of the semi-spinalis colli; its inferior origins lie on the outside of the insertion of the spinalis dorsi. Use: To extend the spine obliquely backwards. Synonyma: Semi-spinalis externus, seu Transverso- spinalis dorsi. The removal of the complexus brings also into view several small muscles situated at the superior part of the neck, immediately below the occiput. 18. The Rectus Capitis Posticus Major— Arises, fleshy, from the side of the spinous process of the dentata, or second cervical vertebra. It ascends ob- liquely outwards, becoming broader, and is Inserted, tendinous and fleshy, into the inferior trans- verse ridge of the os occipitis, and into part of the con- cavity above that ridge. Situation: This muscle is situated obliquely between the occiput-and the second vertebra of the neck. It lies under the complexus; its outer fibres also pass under the insertion of the obliquus capitis superior. 244 Use: To extend and pull the head backwards, and to assist in its rotation. Synonyma: Rectus major;—Spino-axoido-occipital. 19. The Rectus Capitis Posticus Minor— Arises, tendinous and narrow, from an eminence in the middle of the back part of the atlas, or first cervical ver- tebra. It becomes broader, and is Inserted, fleshy, into the inferior transverse ridge of the os occipitis, and into the surface betwixt that ridge and the foramen magnum. Situation: It is partly covered by the rectus capitis posticus major; but a large portion of this pair of mus- tles is seen projecting between the recti majores, and is situated beneath the complexus. Use: To draw the head backwards. Synonyma: Rectus minor;—Tuber-atloido-occipi- tal. 20. Obliquus Capitis Superior—Arises, tendi- nous, from the upper and posterior part of the trans- verse process of the first cervical vertebra. Inserted, tendinous and fleshy, into the inferior trans- verse ridge of the os occipitis behind the mastoid pro- cess, and into a small part of the surface above and be- low that ridge. Situation: This muscle is situated laterally between the occiput and atlas. It is inserted under the com- plexus and trachelo-mastoideus, and it covers some of the outer fibres of the insertion of the rectus capitis pos- ticus major. Use: To draw the head backwards, and to assist in rolling it. 245 Synonyma: Obliquus superior, sive Minor;—Tra- chelo-atloido-occipital. 21. Obliquus Capitis Inferior—Arises, tendi- nous and fleshy, from the side of the spinous process of the dentata or second cervical vertebra. It forms a thick belly, and is Inserted into the under and back-part of the trans- verse process of the atlas. Situation: This muscle is obliquely situated between the two first vertebrae of the neck. It is covered by the complexus and trachelo-mastoideus, except a small part which is seen between these two muscles, and is con- cealed by the splenius. Its origin lies between the ori- gin of the rectus capitis posticus major, and the superi- or insertion of the semi-spinalis colli. Use: To rotate the head,by turning the first vertebra upon the second. Synonyma: Obliquus inferior, sive Major;—Spini- axoido-tracheli-atloidien. 22. The Multifidus Spin^e. On removing the muscles of the spine which have been described, we find situated beneath them the Multifidus Spinae. It is that mass of muscular flesh which lies close to the spinous and transverse processes of the vertebrae, extending from the dentata to the os sa- crum. The bundles of which it is composed seem to pass from the transverse, to be inserted into the spinous processes. Arises, tendinous and fleshy, from the spinous pro- cesses and back-part of the os sacrum, and from the posterior adjoining part of the os ilium; from the x 2 246 oblique and transverse processes of all the lumbar ver- tebra; from the transverse processes of all the dorsal vertebra; and from those of the cervical vertebr», ex- cepting the three first. The fibres arising from this extensive origin pass obliquely, to be Inserted, by distinct tendons, into the spinous pro- cesses of all the vertebra of the loins and back, and into those of the six inferior vertebra of the neck. The fibres arising from each vertebra are inserted into the second one above it, and sometimes more. Use: To extend the back obliquely, or move it to one side. When both muscles act, they extend the verte- bra backwards. Synonyma: Transversalis lumborum dorsi et colli; —Transverso-spinalis lumborum, dorsi et colli; vel Semi-spinalis. The small muscles situated between the processes of the vertebrae are, 1. Interspinales colli, dorsi, et lumborum.— These are small bundles of fibres, which fill up the spaces between the spinous processes of the vertebrae. Each of these little muscles arises from the surface of one spinous process, and is inserted into the next spi- nous process. In the neck they are large, and appear double, as the spinous processes of the cervical vertebrae are bifurcat- ed. In the back and loins they are indistinct, and are rather small tendons than muscles. Use: To draw the spinous processes nearer to each other. 2. The Intertransversalis colli, dorsi, et 247 lumborum, are small muscles which fill up, in a simi- lar manner, the spaces between the transverse proces- ses of the vertebra. In the neck they are bifurcated and distinct, in the back they are small and slender, and in the loins they are strong and fleshy. Use: To draw the transverse processes towards each other. CHAP. XIII. DISSECTION OF THE MUSCLES SITUATED BETWEEN THE RIBS, AND ON THE INNER SURFACE OF THE STERNUM. THE muscles which fill up the space between the ribs are named Intercostals; they are disposed on each side of the thorax in two layers; and each layer consists of eleven muscles. The Intercostales Externi—Arise from the in- ferior acute edge of each superior rib, extending from the spine to near the junction of the ribs with their cartilages. The fibres run obliquely forwards and downwards, and are Inserted into the upper obtuse edge of each infe- rior rib, from the spine to near the cartilage of the rib. 248 Situation: These muscles are seen on removing the muscles which cover the thorax. Synonyma: Inter-Iateri-costaux. The Levatores Costarum are twelve small mus- cles, situated on each side of the dorsal vertebrae. They are portions of the external inttrcostals. Each of these small muscles arises from the transverse process of one of the dorsal vertebra, and passes downwards, to be inserted into the upper side of the rib next below the vertebra, near its tuberosity. The first of these muscles passes from the last cervi- cal vertebra, the eleven others from the eleven supe- rior dorsal vertebra. The three or four inferior Leva- tores are longer, and run down to the second rib below the transverse process from which they arise. Hence Albinus names them the Levatores Costarum, Longio- res et Breviores. Synonyma : Supra-costales. 2. The Intercostales Interni—Arise from the inferior acute edge of each superior rib, beginning at the sternum, and extending as far as the angle of the rib. The fibres run obliquely downwards and back- wards, and are Inserted into the superior obtuse edge of each infe- rior rib from the sternum to the angle. Portions of the internal intercostals pass over one rib, and are in- serted into the next below it. Synonyma: Inter-pleuri-costaux. Thus the intercostal muscles decussate, and are double on the sides of the thorax; but, from the spine to the angles of the ribs, there are only the ex- ternal intercostals, and, from the curtilages to the 249 sternum, only the internal, and some cellular mem- brane covering them. The whole of the internal inter- costals, and the back-part of the external, are lined by the pleura. Use: To elevate the ribs, so as to enlarge the cavity of the thorax. One pair of muscles is situated on the inner surface of the sternum. The Triangularis Sterni, or Sterno-Costalis,— Arises, tendinous and fleshy, from the edge of the whole cartilago ensiformis, and from the edge of the lower half of the middle bone of the sternum. The fibres ascend obliquely upwards and outwards, and form a flat muscle, which is Inserted, by three or four triangular fleshy and ten- dinous terminations, into the cartilages of the third, fourth, fifth, and sixth ribs. Situation: This muscle lies on the inside of the ribs and sternum, and is lined by the pleura. Use: To depress the cartilages and the bony extre- mities of the ribs, and consequently to assist in lessen- ing the cavity of the thorax. 250 CHAP. XIV. DISSECTION OF THE MUSCLES SITUATED ON THE ANTERIOR PART OF THE NECK, CLOSE TO THE VERTEBRAE. FOUR pair of muscles are here situated. 1. The Longus Colli—Arises, tendinous and fleshy, from the sides of the bodies of the three supe- rior dorsal vertebrae, and from the anterior surface of the transverse processes of the four or five lower cervi- cal vertebra. Inserted, tendinous and fleshy, into the fore-part of the bodies of all the vertebrae of the neck. Situation: This muscle lies behind the oesopha- gus, and behind the great vessels and nerves of the neck. Use: To bend the neck forwards, and to one side. Synonyma: Pre-dorso-cervical. 2. The Rectus Capitis Internus Major__ Arises, tendinous and fleshy, from the anterior points of the transverse processes of the third, fourth, fifth, and sixth cervical vertebra. It forms a considerable fleshy belly. Inserted into the cuneiform process of the os occipi- tis a little before the condyloid process. 251 Situation: This muscle lies before the scaleni, and more outwardly than the longus colli, over the part of which it passes. Use: To bend the head forwards. Synonyma: Rectus anterior longus ;—Grand trache- lo-basilaire. 3. The Rectus Capitis Internus Minor— Arises, fleshy, from the fore part of the body of the first vertebra of the neck, near its transverse process ; and, ascending obliquely, is Inserted near the root of the condyloid process of the occipital bone, under the last-described muscle. Use : To bend the head forwards. Synonyma : Rectus anterior brevis ;—Petit-trachelo- basilaire. 4. The Rectus Capitis Lateralis---Arises, fleshy, from the anterior and upper part of the trans- verse process of the atlas. Inserted, tendinous and fleshy, into a scabrous ridge of the os occipitis, which extends from the condyloid process of that bone towards the mastoid process. Situation : It is situated immediately behind the in- ternal jugular vein, where it comes out from the cra- nium. Use : To pull the head a little to one side. Synonyma: Transversalis anticus primus;---Tra- cheli atloido-lattral. 252 C?AP. XV. DISSECTION OF THE SUPERIOR EXTRE- MITY. SECT. I. OF,THE SHOULDER AND ARM. IN the thigh we saw a strong fascia, arising from the neighbouring bones and ligaments, firmly investing the. muscles, and giving origin to some of their fibres ; but, on removing the integuments of the shoulder and arm, we do not meet with any regular fascia. The muscles, like those on the outside of the thorax, are covered by condensed cellular substance; and this sub- stance might be taken for a thin aponeurosis ; but it is widely different in its nature, and ought to be regularly dissected off with the integuments. In removing the integuments, we meet with several cutaneous veins and nerves. The cutaneous veins* of the upper extremity are the following. 1. The Basilic Vein is seen arising from a small * The veins are described from their origin in the fore-arm, for the sake of perspicuity; they ramify above the fascia of the fore-arm. 253 vein on the outside of the little finger, named Salva- tella. It then runs along the inside of the fore-arm near the ulna, receiving the internal and external ulnar veins from the anterior and posterior surface of the fascia. It passes over the fold of the arm near the inner condyle of the humerus; here it is superficial. It ascends along the arm, becoming more deeply seated, and included in the sheath which invests the brachial artery. As it approaches the neck of the humerus, it sinks deep betwixt the folds of the arm-pit, and terminates in the axillary vein, which may be considered as a continuation of the basilic vein. It communicates with the deeper- seated veins, and receives numerous branches from the muscles. 2. The Cephalic Vein begins on the back of the hand, between the thumb and metacarpal bone of the fore-finger, by a small vein, named Cephalica Pollicis. It runs along the radius between the mus- cles and integuments, receiving the internal and ex- ternal radial veips. It passes over the bend of the arm near the external condyle, and ascends along the outside of the arm near the outer edge of the biceps flexor cubiti. It then runs betwixt the edge of the deltoid and pectoral muscles, dips down under the clavicle, and enters the subclavian vein. In all this course, the cephalic vein receives branches. 3. The Median Vein. Several veins are seen running along the middle of the anterior part of the fore-arm. The trunk formed by these veins is called the Mediana Major. It ascends on the flat part of the fore-arm, betwixt the basilic and cephalic veins; y 254 and bifurcates at the fold of the arm into two branch- es: 1. The Mediana Basilica, passing off obliquely to join the basilic vein; 2. The Mediana Cephalica, which joins the cephalic. The cutaneous nerves of the arm are seen ramify- ing above the muscles ; they consist of, 1. The Internal Cutaneous Nerve, a branch of the axillary plexus. It is seen accompanying the basilic vein, and twisting its fibres over it. It des- cends along the inside of the arm, crosses over the fore-part of the elbow-joint, and, in the dissection of the fore-arm, will be seen dividing itself into twigs, which ramify between the fascia and integu- ments, and are distributed to the inside of the fore- arm and wrist. 2. The upper part of the arm receives cutaneous nerves from the branches of the dorsal nerves, which come out of the thorax between the ribs. 3. The shoulder and back-part of the scapula re- ceive twigs from the cervical nerves. 4. The external cutaneous, ulnar, and spiral nerves, also send twigs to the integuments of the arm and fore arm. MUSCLES SITUATED ON THE SHOULDER AND ARM. These are ten in number. 1. The Deltoides—Arises, tendinous and fleshy, from the posterior third of the clavicle, from the whole edge of the acromion, and from the lower margin of the whole spine of the scapula. From 255 these several origins the fibres run in different direc- tions, and converge. Those arising from the clavicle run outwards and downwards : those from the spine of the scapula outwards, forwards, and downwards; and those from the acromion directly downwards. Inserted, tendinous, into a triangular rough sur- face on the outer side of the os humeri, near its middle. Situation: This muscle is entirely superficial, except where the thin fibres of the platysma myoides arise from its anterior surface. It arises from the same ex- lent of bone as the trapezius is inserted into, and is therefore opposite to that muscle which passes up- wards from its origin, while the deltoid runs down- wards. It forms a strong coarse muscle, consisting of large fasciculi of fibres. It conceals the insertion of the pectoralis major, and the origins of the biceps flexor cubiti and coraco-brachialis, and covers the whole of the fore-part and outside of the shoulder- joint. Its insertion is situated betwixt the biceps flexor cubiti and the short head of the triceps exten- sor, and immediately above the origin of the brachilis internus. Its external surface is quite fleshy; but, on cutting it across, its internal surface is found ten- dinous : and, where it slides over the great tuberosity of the humerus, there is a large bursa, or sacculus mucosus. From the insertion of the deltoid to the outer con- dyle of the os humeri, is extended an Intermuscular Ligament, which separates the muscles on the ante- rior part of the arm from those on the posterior part, 256 and gives attachment to the fibres of both. It is named the External Intermuscular Ligament. Use: To draw the arm directly upwards, and .to move it a little forwards or backwards, according to the different directions of its fibres. Reflect it from the scapula and clavicle, that you may expose more completely the muscles on the dorsum of the former 'bone. Synonyma: Sous-acromio-clavi-humeral. The following two muscles, which fill up the posterior surface of the scapula, are covered by a fascia, which adheres to the spine and edges of,that bone. On dissecting off this fascia, the fleshy fibres of the muscles will be found arising from its inner surface. 2. The Supra-Spinatus—Arises, fleshy, from all that part of the base of the scapula that is above its spine, from the superior costa as far forwards as the semilunar nitch, from the spine itself, and from the concave surface betwixt it and the superior costa. The fleshy fibres, as they approach the neck of the scapula, terminate in a tendon which passes under the acromion, slides over the neck of the scapula (to which it is connected by loose cellular membrane), adheres to the capsular ligament of the shoulder-joint, and is Inserted into the anterior and superior part of the great tuberosity near the head of the os humeri. Situation: This muscle fills up the fossa or cavity above the spine of the scapula, and is entirely con- cealed. Its belly is covered by the fibres of the tra- 257 pezius, passing into the spine of the scapula; and it^ tendon passes under the deltoid. Use: To raise the arm. Synonyma : Super-scapularis ;—Sus-spini-scapulo- trochiterien. 3. The Infra-Spinatus—Arises, principally fleshy, from the lower part of the spine of the scapula as far back as the triangular flat surface; from the base of the bone below the spine to near the inferior angle ; from the posterior ridge of the inferior costa; and from all the dorsum of the bone below the spine. The fibres ascend and descend towards a middle ten- don, which runs forwards over the neck of the bone, and adheres to the capsular ligament. Inserted, by a strong short tendon, into the middle part of the great tuberosity of the os humeri. Situation : This muscle is in part concealed. The anterior part of its belly, and its tendinous insertion, are covered by the deltoid, and the trapezius passes over its upper and back part; but a considerable por- tion of the belly of this muscle is seen betwixt these two muscles, and above the superior fibres of the la- tissimus dorsi. It is inserted below the tendon of the supra-spinatus. Use: To roll the humerus outwards, to assist in raising the arm, and in moving it outwards when raised. Synonyma: Sous spini-scapulo-trochiterien. 4. The Teres Minor—Arise*, fleshy, from the narrow depression between the two ridges in the infe- rior costa of the scapula, extending from the neck of the bone to within an inch or two of the inferior y 2 258 angle. It passes forwards along the inferior edge oi the infra-spinatus, adheres to the capsular ligament of the shoulder-joint, and is Insei-tcd, tendinous and fleshy, into the lower and back-part of the great tuberosity of the os humeri. Situation: It is inserted below the tendon of the infra-spinatus. Its origin lies between the infra- spinatus and teres major, and is partly concealed by them. The middle of its belly is superficial, and not covered by any muscle; but its insertion is concealed by the deltoid. The fascia which covers the infra- spinatus envelopes also the teres minor; and the two muscles are, in some subjects, so closely united, as to be with difficulty separated. Use: To draw the humerus downwards and back- wards, and to roll it outwards. Synonyma: Margini-sus-scapulo-trochiterien. 5. The Teres Major—Arises, from an oblong, rough, flatted surface, at the inferior angle of the scapula. It forms a thick belly, which passes for- wards and upwards towards the inside of the arm. Inserted, by a broad thin tendon, into the ridge of the os humeri, at the inner side of the groove for lodging the tendon of the long head of the biceps flexor cubiti. Situation: The origin of this muscle is superficial, and adheres to the lower fibres of the infra-spinatus. Its belly passes before the long head of the triceps extensor cubiti. Its tendon is inserted along with the tendon of the latissimus dorsi. Observe the relative situation of these tendons : they both pass under the coraco-brachialis and short head of the biceps flexor. 259 to reach the place of their insertion. They appear at first inseparably united, but, on dividing them with some care, we find an intermediate cavity lubricated with synovia. The tendon of the latissimus dorsi is anterior to the tendon of the teres major; but the lower edge of the latter extends farther down the arm. Use: To roll the humerus inwards, and to draw it backwards and downwards. Synonyma: Anguli-scapulo-humeral. 6. The Subscapularis—Arises, fleshy, from all the base of the scapula internally, from the superior and inferior costa, and from the whole internal sur- face of the bone. It consists of tendinous and fleshy bundles, which converge, slide over the inner surface of the neck of the scapula, pass in the hollow under the root of the coracoid process, and adhere to the inner part of the capsular ligament of the shoulder- joint. Inserted, by a strong tendon, into the lesser tubero- sity near the head of the os humeri. Situation: The whole of this muscle is concealed by the scapula and muscles of the shoulder. It lies betwixt that bone and the serratus magnus; the ten- don passes under the coraco-brachialis and short head of the biceps flexor, to reach the lesser tuberosity. The lower edge of this muscle is in contact with the upper edge of the teres major. Use: To roll the os humeri inwards, and to draw it to the side of the body. Synonyma: Sous-scapulo-trochinien. 7. The Biceps Flexor Cubiti—Arises by two heads. The first and outermost, called the Long 260 Head, arises, by a strong tendon, from a smooth sur- face in the upper edge of the glenoid cavity of the sca- pula. It passes over the head of the os humeri, with- in the capsular ligament of the shoulder-joint, and en- ters a groove betwixt the two tuberosities of that bone. It forms a strong fleshy belly. The second and in- nermost, called the Short Head, arises, tendinous, from the lower part of the coracoid process of the sca- pula, in common with the coraco-brachialis, and sends off a fleshy belly. These two fleshy bellies are at first only connected by condensed cellular membrane. They form a thick mass, and, below the middle of the arm, become inse- parably united. They send off a strong tendon, which is at first broad, but soon becomes rounder, and passes over the fore-part of the elbow-joint. It then slides over the cartilaginous middle surface of the tubercle at the upper end of the radius, and is Inserted into the posterior and internal rough part of that tubercle. A bursa mucosa is placed between the tendon and front of the tubercle. Situation: The tendon of the long head cannot be seen till the capsular ligament of the shoulder is open- ed. Where it runs in the groove of the os humeri, it lies betwixt the pectoralis major and latissimus dorsi, and is firmly bound down by tendinous fibres passing from the capsular ligament and adjacent tendons. The short head arises from the coracoid process, be- twixt the origin of the coraco-brachialis and the strong ligament which passes from the coracoid pro- cess to the acromion. These two origins are conceal- ed by the deltoides and pectoralis major. The belly of 261 the muscle is immediately under the integuments, and so is the tendon where it passes over the elbow-joint. It is seen sinking between the supinator radii longus and pronator teres, to arrive at its point of insertion ; and at the bend of the elbow, it sends off from its in- side an aponeurosis, which assists in forming the fas- cia of the fore-arm. Use: To turn the hand supine, to bend the fore- arm on the arm, and the arm on the shoulder. Synonyma: Biceps brachii;—Biceps, sive Coraco- radialis;—Biceps internus ;—Scapulo-coraco-radial. 8. The Coraco Brachialis—Arises, tendinous and fleshy, from the middle part of the apex of the coracoid process of the scapula. Its fibres, as it de- scends, also arise from the edge of the short tendon of the biceps flexor cubiti. It forms a flat fleshy belly which is always perforated by the nerve, named Mus- culo-Cutaneus. Inserted, tendinous and fleshy, about the middle of the internal part of the os humeri, into a rough ridge. Situation: This muscle is much connected with the short head of the biceps flexor cubiti. It arises betwixt that muscle and the origin of the pectoralis minor. In the arm, it lies behind, and on the inside ol the bi- ceps, and is concealed by the pectoralis major and deltoides, excepting a small part of it which is seen projecting betwixt the biceps flexor and triceps ex- tensor cubiti. It is inserted immediately below the tendons of the latissimus dorsi and teres major, and before the brachialis externus. The lower part of 262 its insertion passes betwixt the brachialis internus and brachialis externus. The internal intermuscular ligament is seen ex- tending from the lower part of this muscle along a ridge to the internal condyle, and separating the bra- chialis internus from the brachialis externus, or third head of the triceps extensor cubiti. Use: To move the arm upwards and forwards. Synonyma: Coraco-humeral. 9. The Brachialis Internus—Arises from the middle of the os humeri, by two fleshy slips, which pass on each side of the insertion of the deltoid mus- cle; fleshy from all the fore-part of the bone below, nearly as far as the condyles. The fibres converge, pass over the elbow-joint, and adhere to the capsular ligament. Inserted, by a strong short tendon, into the rough surface immediately below the coronoid process of the ulna. Situation: The most external of the fleshy slips of this muscle lies between the deltoid and short head of the triceps extensor, the internal between the deltoid and coraco-brachialis. The belly is almost entirely concealed by the biceps flexor cubiti, excepting a small portion which projects beyond the outer edge of that muscle. The tendon dips down betwixt the su- pinator radii longus and pronator teres, crosses under the tendon of the biceps flexor, and is inserted on the inside of that tendon. Use: To bend the fore-arm. Synonyma: Brachiaus ;—Humero-cubital. 263 10. The Triceps Extensor Cubiti is the great muscle which covers all the back-part of the arm- It arises by three heads. The first, or long head, arises, by a broad tendon, f om the inferior costa of the scapula near its cervix, and forms a large belly, which covers the back-part of the os humeri. The second, or,short head, arises, on the outer and back- part of the os humeri, by an acute tendinous and fleshy beginning, from a ridge which runs from the back-part of the great tuberosity towards the outer condyle. The fibres begin to arise a little below the tuberosity, and are continued down to the condyle. They also arise from the surface of bone behind the ridge, and from the intermuscular ligament which separates them from the muscles on the fore-part of the arm. The third head, called Brachialis Ex- ternus, arises, by an acute beginning, from the in- side of the os humeri above its middle, and from a ridge extending to the inner condyle. It also arises from the surface behind this ridge, and from the in- ternal intermuscular ligament. The three heads unite above the middle of the os humeri, and invest the whole back-part of the bone. They form a thick strong tendon, which is Inserted into the rough back-part of the process of the ulna, called Olecranon, and partly into the con- dyles of the os humeri, adhering firmly to the capsu- lar ligament. Situation: The long head, where it arises from the scapula, is concealed by the deltoid ; it arises betwixt ^ the teres minor and teres major, and passes betwixt those muscles to the arm; and, in the remainder of 264 its course, is superficially seated. The short head arises immediately below the insertion of the teres minor, its upper part is therefore covered by the del- toides. Below the deltoid, it is superficial, and arises more outwardly than the brachialis internus, supina- tor radii longus, and extensors of the carpus. The brachialus externus is situated immediately under the integuments; it begins to arise below the insertion of the teres major. It passes down the arm between the triceps longus and coraco brachialis at first, after- wards between the triceps longus and brachialis inter- nus. The tendon of the triceps sends off a thin fascia, which covers the triangular surface of the ulna, on which we commonly lean. Numerous fibres are also sent off, to assist in forming the fascia of the fore-arm. Use: To extend the fore-arm. The longhead will also assist in drawing the arm backwards. Synonyma: Anconeus major, Anconeus externus., and Anconeus internus;—Biceps externus, and Bra- chialis externus;—Triceps Brachii;—Tri-scapulo-hu- mero-olecranien. SECT. II. DISSECTION OF THE FASCIA AND MUSCLES SITUATED ON THE CUBIT OR FORE-ARM*. On removing the integuments of the fore-arm, we * In the following description, the palm of the hand is sup- posed to be turned forwatds, so that the radius and thumb are upon the outer side of the fore-arm, and the ulna and little finger upon its inner side. 265 find, as in the leg, a strong fascia investing all the muscles. This fascia is continued from the inter- muscular ligaments which pass down to the condyles of the os humeri. It is attached to the condyles, and it adheres firmly to the olecranon of the ulna. It re- ceives, on the posterior part, a great addition of fibres from the tendon of the triceps extensor; and on the fore-part of the arm, it appears to be a conti;uiation of the aponeurosis which is sent off from the biceps flexor cubiti. Above the fascia, we meet with several cutaneous veins and nerves. The veins have been already de- scribed: the nerves are twigs of the branches of the brachial plexus. The relative situation of the vessels at the bend of the arm should be well attended to. The cutaneous veins situated here vary much in size. The vena ba- silica is seen running over the fore-part of the bend of the arm near the inner condyle, the vena cephalica situated near the outer condyle ; and each of these veins receives a branch passing obliquely from the vena mediana major. These vessels lie above the fas- cia, while the brachial artery lies deep beneath the fascia, in a hollow resembling that of the axilla. It descends over the joint near the inner condyle, on the inside of the tendon of the biceps flexor cubiti, and under the aponeurosis sent off from that muscle to the common fascia of the fore-arm. It lies embedded in cellular substance, betwixt the pronator teres and flexor muscles of the wrist and fingers on one side, and the supinator longus and extensor muscles on the other. In this hollow it divides into the radial, ul- z 266 nar, and interosseal arteries. The artery is accom- panied by two veins, and on its inner side runs the radial nerve. The dissection of the fascia of the fore-arm is simi- lar to that of the fascia of the leg. It is found firmly attached to the fibres of the muscles, so that the ex- posed surface appears ragged. It sends down betwixt them partitions, named Intermuscular Ligaments or Tendons, Which connect the muscles, and give origin to many of their fibres. MUSCLES SITUATED ON THE FORE-PART OF THE CUBIT, AND ARISING FROM THE INNER CONDYLE OF THE OS HUMERI. These are eight in number, and may be divided into two classes: the superficial, and the deep-seated.' First, The superficial. All the muscles passing from the inner condyle may be said to arise by one common tendinous head from the condyle; and this head may be said to divide into the different muscles; but they will be here de- scribed'as arising distinct from the condyle. It must, however, be recollected, that their origins are inti- mately connected by intermuscular ligaments, and that they cannot be separated without dividing some of their fibres. 1. The Pronator Radii Teres—Arises, ten- dinous and fleshy, from the anterior surface of the in- ner condyle of the os humeri, and from the coronoid process of the ulna. It also arises from the fascia of 267 the fore-arm. The fibres pass outwards, run by the side of the tubercle of the radius, and pass over the outer edge of that bone, to be Inserted, tendinous and fleshy, into a rough surface on the back-part of the radius about its middle. Situation: Of the muscles which pass from the in- ternal condyle, the^pronator teres is situated nearest the outer edge of the arm. It lies immediately on the inside of the tendon of the brachialis internus. Its tendon, to arrive at its place of insertion, passes under the belly of the supinator longus, and, when that muscle is removed, will be found inserted into the ra- dius immediately below the supinator brevis. Use : To roll the radius, together with the hand, inwards. Synonyma : Pronator teres, sive Obliquus;—Epi- trochlo-radial. 2. The Flexor Carpi Radialis—Arises, by a narrow tendinous begining, from the lower and fore- part of the internal condyle of the os humeri; fleshy from the fascia and intermuscular ligaments, and from the upper end of the ulna. It forms a thick belly, which runs down the fore-arm, and terminates in a flat tendon. This tendon passes under the annular li- gament * of the wrist, runs through a groove in the os trapezium, and is » The annular ligament of the wrist consists of two parts. 1. The ligamentum carpi transversale externum passes from the styloid process of the ulna and os pisiforme, transversely, over the back of the wrist, and spreads out broad, to be affixed to the styloid process of the radius. Under it pass the tendons of the extensor muscles. % The ligamentum carpi transversale 268 Inserted into the fore-part of the base of the meta- carpal bone sustaining the fore-finger. Situation: This muscle is situated immediately un- der the fascia, excepting its upper extremity, over which the pronator teres crosses. It arises between the pronator teres and palmaris longus, and descends betwixt those muscles. Below the insertion of the pronator, it is situated betwixt the supinator radii longus and palmaris longus. Its insertion cannot be seen till the palm of the hand is dissected, where it will he found concealed by the muscles of the ball of the thumb. Use: To bend the hand, and to assist in its prona- tion. Synonyma: Radialis internus;—Epitrochlo-meta- earpien. 3. The Palmaris Longus—Arises, by a slender tendon, from the fore-part of the inner condyle of the os humeri; and fleshy, from the intermuscular liga- ments ; it forms a short fleshy belly, which soon sends off a long slender tendon. This tendon descends along the fore-arm, and is Inserted, near the root of the thumb, into the" liga- mentum carpi transversale internum, and into a ten- dinous membrane that covers the palm of the hand, named Fascia, or Aponeurosis Palmaris. Situation: It arises betwixt the flexor carpi radialis and flexor ulnaris. Its tendon descends betwixt these internum is a strong ligament, which passes across the fore-part of the wrist. It arises from the os pisiforme and os unciforme on the inner edge of the wrist, and is attached to the os scaphoides and os trapezium on the outer edge. Under it pass the tendons of the flexor muscles. I 269 two muscles, and above the fibres of the flexor digi- torum sublimis. This muscle is sometimes wanting. Use: To bend the hand, and to stretch the palmar aponeurosis. Synonyma: Ulnaris gracilis;—Epitrochlo-carpi- palmaire. 4. The Flexor Carpi Ulnaris—Arises, tendi- nous, from the inferior part of the internal condyle of the os humeri; tendinous and fleshy, from the inner side of the olecranon, and by a tendinous expansion from the posterior ridge * of the ulna, to near the lower end of the bone. It also arises from the inter- muscular ligaments and fascia of the fore-arm. The fibres pass obliquely forwards into a tendon which runs over the fore-part of the ulna, and is Inserted into the os pisiforme, and sometimes sends its fibres over a small ligament which goes to the base of the metacarpal bone of the little finger. Situation: This muscle arises behind the other muscles which pass from the internal condyle. It runs along the inner edge of the fore-arm, between the flexor sublimis en the fore-part, and the extensor carpi ulnaris on the back-part of the ulna. The ten- don is bound down by a thin aponeurotic slip, which passes from the inner part of the annular ligament of the wrist. Use: To bend the hand. Synonyma: Ulnaris internus;—Epitrochli-cubito- carpien. . 5. The Flexor Sublimis Perforatus—^wm, tendinous and fleshy, from the under part of the inter- * The ridge which leads to the styloid process. z 2. 270 nal condyle of the os humeri; tendinous, from the lower part of the coronoid process of the ulna ; fleshy, from the tubercle of the radius, from the middle of the fore-part of that bone, and from the middle third of its outer edge. These origins form a strong fleshy mass, which sends off four tendons. The ten- dons are connected by cellular membrane, and pass together under the annular ligament of the wrist; after which they separate, become thinner and flatter, pass along the metacarpal bone and first phalanx of each of the fingers, and are Inserted into the anterior and upper part of the se- cond phalanx, each tendon being, near the extremity of the first phalanx, divided.for the passage of a tgn- don of the flexor profundus. Situation: To expose the origin of this muscle, the bellies of the pronator teres, flexor carpi radialis, and palmaris longus, must be detached from the condyle. It arises behind these muscles, and is connected to them by intermuscular ligaments. It descends along the fore-arm under these muscles, but a part of it is seen projecting towards the inner edge of the arm, betwixt the tendons of the palmaris longus and flexor carpi ulnaris. It arises from the radius immediately below the insertion of the biceps flexor cubiti, and on the inside of the insertion of the pronator teres. Its tendons Will be seen in the dissection of the palm of the hand. Use: To bend the second joint or phalanx of the fingers. Synonyma: Sublimis ;—Perforatus ;—Epitrochlo- coroni-phalanginien. 271 By removing the belly of the flexor sublimis, we expose the deep-seated muscles. 6. The Flexor Profundus Perforans— Arises, fleshy, from the smooth concavity on the in- side of the ulna, betwixt the coronoid process and the olecranon; from the smooth flat surface of the ulna, betwixt its posterior and internal angles; from the under part of the coronoid process; from the fore-part of the ulna below that process, and betwixt the inter- nal angle and that angle which gives attachment to the interosseous ligament. It also arises from the in- ner half of the interosseous ligament. This muscle forms a thick mass, which descends along the fore- part of the ulna, adhering to that bone as low as one- third of its length from its inferior extremity, and ter- minates in sending off four tendons. These tendons are flat, pass together under the annular ligament of the wrist, run through the slits in the tendons of the flexor sublimis, and are Inserted into the fore and upper part of the third or last phalanx of all the fingers. Situation: This muscle is concealed by the flexor sublimis and flexor carpi ulnaris. Its tendons will be seen in dissecting the hand. Use: To bend the last joint of the fingers. Synonyma : Profundus; —Perforans ;—Cubito-pha- langettien commun. 7. Flexor Longus Pollicis Manus—Arises, by an acute fleshy beginning, from the upper and fore part of the radius, immediately below its tubercle, fleshy, from the outer edge and anterior surface of that 272 bone as low as two inches above its inferior extremity, and from the outer part of the interosseous ligament. It has also generally a tendinous origin from the in ternal condyle of the os humeri. This origin forms a distinct fleshy slip, which is joined to the inner and upper part of the portion of the muscle arising from the radius. The fibres pass obliquely into a tendon on the anterior surface of the muscle. The tendon passes under the annular ligament of the wrist, runs between the two heads of the short flexor of the thumb, and between the two sesamoid bones, and is Inserted into the base of the extreme phalanx of the thumb. Situation: This muscle lies by the side of the flexor profundus; the portion which arises from the inner condyle passes over the belly of the flexor pro- fundus, and under the flexor sublimis. The whole muscle is concealed by the flexor sublimis; its tendon will be seen in dissecting the short muscles of the thumb. Use: To bend the last joint of the thumb. Synonyma: Flexor tertii internodii;—Radio-phalan- gettien du pouce. On separating the lower part of the two last-de- scribed muscles, we expose a small square muscle, passing transversely just above the wrist. 8. The Pronator Quadratus—Arises, broad, tendinous, and fleshy, from the inner edge of the ulna, extending from the lower extremity of the bone two inches up its edge. The fibres run transversely, ad- here to the interosseous ligament, and are 273 Inserted into the lower and anterior part of the ra- dius. Situation: This muscle lies close to the bones, co- vered by the flexor longus pollicis and flexor digito- rum sublimis. Use: To turn the radius, together with the hand, inwards. Synonyma: Cubito-radial. muscles situated on the outer and back part OF THE FORE-ARM, AND ARISING FROM THE OUTER CONDYLE OF THE OS HUMERI. These muscles are eleven in number, and may be divided into two classes: 1. The Superficial; and, 2. The Deep-seated. The Superficial. The muscles which arise from the outer condyle are much more distinct in their origins than those which arise from the inner condyle. Several of them arise a considerable way up the os humeri; but there is here also a common tendinous origin, from which the extensor carpi radialis brevior, extensor digitorum communis, and extensor carpi radialis, proceed; so that these muscles are intimately connected. 1. Supinator Radii Longus—Arises, tendi- nous and fleshy, from the external ridge of the os humeri which leads to the outer condyle. It begins to arise nearly as far up as the middle of the bone, and ceases to adhere about two inches above the con- 274 dyle. It forms a thick fleshy belly, which passes over the side of the elbow-joint, becomes smaller, and terminates above the middle of the fore-arm in a flat tendon. The tendon becomes gradually rounder, and is Inserted into a rough surface on the outer side of the inferior extremity of the radius. Situation: This muscle is situated immediately under the integuments along the outer edge of the arm and fore-arm. It begins to arise from the os humeri immediately below the insertion of the del- toid. Its origin lies betwixt the brachialis internus and short head of the triceps extensor cubiti, from which it is separated >y the external intermuscular ligament. It descends along the radius, placed at hrst between the extensor carpi radialis longior and pronator teres, lower down between the tendons of the flexor carpi radialis and extensor radialis lon- gior. Its insertion is crossed by the extensors of the thumb. Use: To roll the radius outwards, and turn the palm of the hand upwards; also to bend the fore-arm on the humerus. Synonyma: Supinator longus, sive major;—Hume- ro-sus-radial. 2. The Extensor Carpi Radialis Longior— Arises, tendinous and fleshy, from the external ridge of the os humeri, beginning immediately below the origin of the supinator longus, and continuing to arise as far as the upper part of the outer condyle. It forms a thick short belly, which passes over the side of the elbow-joint, and terminates above the middle 275 of the radius in a flat tendon. The tendon runs along the radius, and, becoming rounder, passes through a groove in the back-part of the inferior extremity of that bone, to be Inserted into the posterior and upper part of the metacarpal bone of the fore-finger. Situation: The belly lies under the supinator lon- gus, but part of it projects behind that muscle. The tendon descends behind that of the supinator, and passes under the extensors of the thumb, and annular ligament of the wrist, to arrive at the place of its in- sertion. Use: To extend the wrist, and move the hand backwards, and to assist in bending the fore- arm. Synonyma: Radialis externus longior;—Radialis ex- ternus primus;—Humero-sus-metacarpien. 3. The Extensor Carpi Radialis Brevior— Arises, tendinous, from the under and back-part of the external condyle of the os humeri, and from the external lateral ligament of the elbow-joint. Its thick belly runs along the outside of the radius, and termi- nates in a tendon, which passes through the same groove in the radius as the extensor radialis longior, and under the annular ligament. Inserted, by a round tendon, into the upper and back part of the metacarpal bone that supports the middle finger. Situation: This muscle lies partly under the exten- sor radialis longior; but it also projects behind it. The tendon is seen behind, or more inwardly than 276 the tendon of the long extensor ; it passes under the extensors of the thumb and the indicator. Use: To extend the hand. Synonyma: Radialis externus brevior;—Radialis secundus epicondylo-sus-metacarpien. 4. The Extensor. Digitorum Communis— Arises, tendinous, from the under part of the external condyle of the os humeri; fleshy, from the intermus- cular ligaments which connect it to the extensor car- pi radialis brevior before, and the extensor carpi ul- naris behind, and from the inner surface of the fascia. It descends along the back-part of the fore-arm, and adheres to the ulna where it passes over it. The fleshy belly terminates in four flat tendons, which pass under the annular ligament in a depression on the back-part of the radius, and are Inserted into the posterior part of all the bones of the fingers by a tendinous expansion. Situation: It arises betwixt the extensor radialis brevior and the extensor carpi ulnaris. It descends betwixt these muscles, and is situated immediately under the integuments. The tendons are connected on the back of the metacarpal bone by cross slips.— The inner part of this muscle is sometimes described as a separate muscle, and is called Extensor Proprius Minimi Digiti, vel Auricularis. It passes through a separate depression of the radius, and a particular ring of the annular ligament. Use: To extend all the joints of the fingers. Synonyma: Epicondylo-sus-phalangettien commun. The posterior surface of each finger is covered with 277 a tendinous expansion which is formed by the tendons of the common extensor, of the lumbricales, and in- terossei. This tendinous expansion terminates in the third or extreme phalanx. 5. The Extensor Carpi Ulnaris—Arises, tendi- nous, from the under part of the external condyle; fleshy, from the intermuscular ligaments and inside of the fascia. It crosses towards the ulna, and arises, fleshy, from the back-part of that bone. It terminates in a strong tendon, which passes through a groove in the back-part of the lower end of the ulna, under the annular ligament, and is Inserted into the posterior and upper part of the metacarpal bone of the little finger. Situation: This muscle is entirely superficial. It arises from the condyle betwixt the extensor digito- rum communis and anconeus. It descends along the fore-arm betwixt the extensor digitorum communis and flexor carpi ulnaris. Use: To extend the wrist, and bring the hand back- wards ; but chiefly to bend the hand laterally towards the ulna, as it will appear by pulling its tendon in the dissected subject. Synonyma: Ulnaris externus;—Epicondylo-cubito- sus-metacarpien. 6. The Anconeus is a small triangular muscle, situated at the outer side of the olecranon, immediate- ly under the integuments. It arises, tendinous, from the posterior and lower part of the external condyle of the os humeri; forms a thick triangular fleshy mass, adhering to the capsu- lar ligament of the elbow-joint, and is a a 278 Inserted into the concave surface on the outside of the olecranon, ana into the posterior edge of the ulna. Situation: This muscle lies betwixt the upper part of the extensor carpi ulnaris and the olecranon. It is partly covered by the tendon of the triceps extensor cubiti, and is enveloped in a fascia sent off from that tendon. Use: To assist in extending the fore-arm. Synonyma: Anconeus minor;—Anconeus vel Cubi- talis;—Epicondylo-cubital. By removing the superficial muscles, we expose The Deep-seated. 7. The Supinator Radii Brevis—Arises, ten- dinous, from the lower part of the external condyle of the os humeri; tendinous and fleshy, from the ridge running down from the coronoid process along the outer surface of the ulna. The fibres adhere firmly to the ligament that joins these two bones, pass outwards round the upper part of the radius, and are Inserted into the upper and outer edge of the tuber- cle of the radius, and into an oblique ridge extending from the tubercle downwards and outwards to the in- sertion of the pronator teres. Situation: This muscle nearly surrounds the upper and outer part of the radius. It is concealed at the outer edge of the arm by the supinator longus and ex- tensores carpi radialis; behind, by the extensor digi- torum communis, extensor carpi ulnaris, and anco- 279 neus; before, by the brachialis internus, and by the tendon of the biceps flexor cubiti, close to which ten- don this muscle is inserted. Use: To roll the radius outwards, and bring the hand supine. Synonyma: Epicondylo-radial. On the back-part of the fore-arm we meet with three muscles going to the thumb, and one to the fore-finger. 8. The Extensor Ossis Metacarpi Pollicis —Arises, fleshy, from the middle and posterior part of the ulna, immediately below the termination of the anconeus, from the interosseous ligament, and from the posterior surface of the radius below the insertion of the supinator radii brevis. The fleshy fibres terminate in a tendon which passes through a groove in the outer edge of the lower extremity of the radius. Inserted, generally by two tendons, into the os tra- pezium, and into the upper and back-part of the meta- carpal bone of the thumb. Use: To extend the metacarpal bone of the thumb outwardly. Synonyma : Abductor longus pollicis manus;—Ex- tensor primi internodii;—Extensor primus pollicis; —Cubito-radi-sus-metacarpien du pouce. 9. The Extensor Primi Internodii Pollicis Manus—Arises, fleshy, from the back-part of the ulna below its middle, from the interosseous ligament and radius. It runs along the lower edge of the ex- tensor ossis metacarpi, and forms a tendon, "which 280 passes through the same groove as the tendon of that muscle, and is Inserted into the posterior part of the first bone of the thumb. Part of the tendon is also continued into the base of the second or extreme phalanx. Use: To extend the first phalanx of the thumb ob- liquely outwards. Synonyma: Extensor minor pollicis manus;—Ex- tensor secundi internodii;—Extensor pollicis primus; —Cubito-sus-phalangien du pouce. 10. The Extensor Secundi Internodii Polli- cis Manus—Arises, tendinous and fleshy, from the posterior surface of the ulna above its middle, and from the interosseous ligament. Its belly partly covers the origins of the two other extensors of the thumb, and terminates in a tendon, which runs through a distinct groove in the back-part of the ra- dius, and is Inserted into the posterior and upper part of the second or extreme phalanx of the thumb. Use: To extend the last joint of the thumb oblique- ly backwards. Synonyma: Extensor major pollicis manus;—Ex- tensor pollicis secundus;—Extensor tertii internodii; —Cubito-sus-phalangettien du pouce. Situation to be Inserted, tendinous, into the inner part of the root of the first phalanx of the thumb. Situation: The belly of this muscle is concealed, as it lies close to the bone under the tendons of the flexor profundus and lumbricales. The tendon is seen where it is inserted into the thumb, and runs along the inner edge of the flexor brevis pollicis. Use: To pull the thumb towards the fingers. Synonyma: Adductor ad minimum digitum ;-~Me- sothenar ;—Metacarpo-phalanginien du pouce. 5. The Abductor Indicis Manus—Arises, ten- 287 ilinous and fleshy, from the os trapezium, and from the inner side of the metacarpal bone of the thumb. It forms a fleshy belly, runs over the side of the first joint of the fore-finger, and is Inserted, by a short tendon, into the outer side of the root of the first phalanx of the fore-finger. Situation: This muscle is seen most distinctly on the back of the hand. It is there superficial, and is crossed by the tendon of the extensor secundi inter- nodii pollicis. In the palm of the hand it is concealed by the muscles of the ball of the thumb. Use: To move the fore-finger towards the thumb, or the thumb towards the fore-finger. Synonyma: Semi-interosseus. The insertion of the flexor carpi radialis is exposed by removing the muscles of the thumb. The short muscles of the little finger are three in number. 1. The Abductor Minimi Digiti Manus— Arises, fleshy, from the os pisiforrne, and adjacent part of the annular ligament of the wrist. Its fibres ex- tend along the metacarpal bone of the little finger. Inserted, tendinous, into the inner side of the first phalanx, and into the tendinous 'expansion which co- vers the back-part of the little finger. - Situation : The belly of this muscle is superficial. It is only covered by the straggling fibres of the pal- maris brevis. Use: To draw the little finger from the rest. Synonyma: Hypotnenar minor;-Extensor tertii internodii minimi digiti ;-CarPo-Phalangien du petit doigt. 288 2. The Flexor Parvus Minimi Digiti— Arises, fleshy, from the outer side of the os uncifor- me, and from the annular ligament of the wrist, where it is affixed to that bone. Inserted, by a roundish tendon, into the base of the first phalanx of the little finger. Situation: This muscle is also covered by the fibres of the palmaris brevis. It lies on the inner side of the abductor minimi digiti, and its tendon is firmly connected to the tendon of that muscle. Use: To bend the little finger, and bring it towards the other fingers. Synonyma: Abductor minimi digiti;—-Carpo pha- langien second. 3. Adductor Metacarpi Minimi Digiti Ma- nus—Arises, fleshy, from the os unciforme, and adja- cent part of the annular ligament of the wrist. It forms a thick mass, which is Inserted, tendinous, into the fore-part of the me- tacarpal bone of the little finger, nearly its whole length. Situation: It is concealed by the bellies of the ab- ductor and flexor.brevis minimi digiti. Use: To bend and bring the metacarpal bone of the little finger towards the rest. Synonyma: Metacarpus;—Flexor primi internodii minimi digiti;—Carpo-metacarpien du petit doigt. The Interossei are small muscles situated be- tween the metacarpal bones, and extending from the bones of the carpus to the fingers. They are exposed by removing the other muscles of the thumb and fingers. 289 The Interossei Interni are seen in the palm of the hand, and are four in number. They arise, tendinous and fleshy, from the base and sides of the metacarpal bones, and are inserted into the side of the first phalanx of the fingers, and into the tendinous expansion which covers the posterior surface of all the phalanges. 1. The First, named Prior Indicis, arises from the outer part of the metacarpal bone of the fore-finger; and is inserted into the outer side of the first phalanx of that finger. Use: To draw the fore-finger towards the thumb. 2. The Second, named Posterior Indicis, arises from the root and inner side of the metacarpal bone of the fore-finger; and is inserted into the inner side of the first phalanx of the fore-finger. Use: To draw that finger outwards. 3. The Third, named Prior Annularis, arises from the root and outer side of the metacarpal bone of the ring-finger; and is inserted into the outer side of the first phalanx of the same finger. Use: To pull the ring-finger towards the thumb. 4. The Fourth, named Interosseus Auricularis, arises from the root and outer side of the metacarpal bone of the little finger; and is inserted into the outer side of the first phalanx of the little finger. Use: To draw the little finger outwards. The internal interossei also assist in extending the fingers obliquely. Synonyma: Sous-metacarpo lateri-phalangiens. The Interossei Externi, seu Bicipites, are three in number. They are larger than the internal, and are situated betwixt the metacarpal bones on the b b 290 back of the hand. Each of these muscles arises, by a double head, from two metacarpal bones, and is in. serted into the side of one of the fingers, and into the tendinous expansion which covers the posterior part of the phalanges. 1. The First, named Prior Medii, arises from the roots of the metacarpal bones of the fore and middle fingers; and is inserted into the outer side of the mid- dle finger. Use: To draw the middle finger towards the thumb. 2. The Second, named Posterior Medii, arises from the roots of the metacarpal bones of the middle and ring fingers; and is inserted into the inner side of the middle finger. Use: To draw the middle finger towards the ring-finger. 3. The Third, named Posterior Annularis, arises from the roots of the metacarpal bones of the ring and little fingers; and is inserted into the inner side of the ring-finger. Use: To draw the ring-finger inwards. The external interossei also extend the fingers. Synonyma: Sous-metacarpo-lateri-phalan- giens. SECT. IV. OF THE VESSELS AND NERVES OF THE SUPERIOR EXTREMITY. ARTERIES. The subclavian and axillary arteries have been de- scribed. The Brachial Artery may be said to have its course along the inside of the arm. Having left the 291 axilla, it runs along the inferior edge of the coraco- brachialis. Rather higher up than the middle of the os humeri, it crosses over the tendinous insertion of that muscle, being here situated between the belly of the biceps flexor cubiti, and the superior fibres of the brachialis externus. The artery then passes behind the inner edge of the biceps flexor cubiti, descending betwixt that muscle and the fibres of the brachialis internus. In dissecting this vessel, we find it invested by a fascia or sheath, formed by cellular membrane and some tendinous fibres. This fascia may be traced extending from the internal intermuscular ligament. It covers the brachial artery and radial nerve; and the great basilic vein, as it enters into the axilla, is found lying in the fore and inner part of this sheath. It supports and connects these vessels. On dissecting this fascia, we find, close to the margin of the cora- co-brachialis and biceps flexor cubiti, the great radial nerve ; under it the brachial artery; and, more su- perficially seated, the vena: comites and the vena ba- silica. As the artery approaches the lower extremity of the os humeri, it inclines forwards toward the fold of the arm, and dives beneath the aponeurosis which arises from the inside of the tendon of the biceps flexor cubiti. Its situation at the fold of the arm has been described. Branches of the Brachial Artery. 1. A. Profunda Humeri Superior, or Mus- cularis Superior, is sent off from the inner side of the brachial artery, immediately where it has left the fold of the arm-pit. It passes downwards and back- wards round the os humeri, and is accompanied by 292 the muscular or spiral nerve. It passes betwixt the brachialus externus and short head of the triceps ex- tensor cubiti. Here it lies deep among the muscles, and divides into two branches. One accompanying the nerve spreads its ramifications over the outer con- dyle, and anastomoses with the arteries below the el- bow. The other branch is distributed along the inside of the arm, and about the inner condyle. 2. A. Profunda Humeri Inferior, vel Mi- nor, or Muscularis Inferior, is smaller than the last, and is sent off from the brachial artery about two inches lower down. It descends among the muscles on the inside of the arm, and is lost about the inner condyle. 3. The anastomosing or collateral arteries are as follow. (1.) The Ramus Anastomoticus Major passes from the inside of the brachial artery, about two or three inches above the inner condyle. It is distributed about the condyle; and its principal branch accom- panies the ulnar nerve in the groove betwixt the ole- cranon and inner condyle, to anastomose with the re- current branches of the arteries of the fore-arm. (2.) There are two or three more anastomosing branches, which are sent off from the brachial artery, and ramify over the anterior and posterior surfaces of the two condyles. 4. Small branches to the muscles of the arm. The Brachial Artery, where it lies deep under the aponeurosis of the biceps, divides into three branches. 1. The radial; 2. The ulnar; and, 3. The interos- seous artery. The two last generally come off by one trunk, which subdivides. 293 I. Arteria Radialis, the radial artery, is smaller than the ulnar, and in its course more super- ficial. It leaves the ulnar artery, and inclines towards the radial or outer edge of the fore-arm. At first it lies betwixt the pronator teres and supinator longus. It then descends close along the inner edge: of the su- pinator longus, and about the middle of the fore-arm passes over the insertion of the pronator teres, It then holds its course betwixt the supinator longus and flexor carpi radialis, and is accompanied by a branch of the muscular or spiral nerve. In this situation the artery continues its course along the radius, till, reaching the lower extremity of that bone, it divides into two branches. (1.) Ramus Volaris, A. Superficialis Vol^e, is by much the smallest of the two branches. It passes into the muscular mass which forms the ball of the thumb, and spreads its ramifications on the palmar fascia, annular ligament of the wrist, and muscles of the thumb, anastomosing with the ramifications of the superficial palmar arch. (2.) The trunk of the radial artery crosses over the lower extremity of the radius to the back of the hand. It passes under the extensors of the thumb, over the os scaphoides and the junction of the os tra- pezium and trapezoides, and, arriving at. the space betwixt the bases of the metacarpal bones of the thumb and fore-finger, plunges into the palm of the hand. The branches of the radial artery,; in its course along the fore-arm, are the following. (1.J The recurrent artery is-sent off from the ra- dial immediately after it leaves the ulnar artery, and Bb 2 294 is distributed over the anterior part of the outer con- dyle, where it anastomoses with branches of the bra- chial artery. (2.) Small arteries to the muscles of the fore-arm, and to the radius. (3.) A branch leaves the artery immediately after it has turned over the edge of the radius, and, rami- fying on the back of the hand, is named Dorsalis Carpi. (4.) Small vessels are sent off to the back-part of the thumb, named A. Dorsales Pollicis. Having reached the palm of the hand, the radial ar- tery divides into two branches. (1.) A. Pollicis, which sends two or three arteries along the anterior part of the thumb, and also often gives.off a twig, the A. Radialis Indicis, which passes along the outer edge of the fore-finger, and inoscu- lates with a branch of the ulnar artery. (2.) The trunk of the radial artery forms the Deep-seated Palmar Arch. From the root of the thumb, it passes across the metacarpal bones near their bases, and terminates at the metacarpal bone of the little finger, inosculating with a branch of the ul- nar artery. This arch lies deep, close to the bones. It supplies the interosseous muscles and deep-seated parts of the palm, and some of its branches pass betwixt the metacarpal bones to the back of the hand. 2. Arteria Ulnaris, or Cubitalis. The ulnar artery is the largest branch of the brachial, and gene- rally gives off the interosseous artery. It takes its course deep among the muscles on the inside of the fore-arm. It is seen passing under the pronator teres, 295 flexor carpi radialis, palmaris longus, and flexor sub- limis perforatus, but over the flexor profundus per- forans. It descends in the connecting cellular mem- brane between the flexor sublimis and profundus; but about the middle of the fore-arm, it emerges from these muscles, and appears at the ulnar edge of the arm, betwixt the flexor sublimis and flexor carpi ulnaris. It passes over the annular ligament of the wrist, which binds down the flexor tendons of the fingers, but is covered by the fascia which ties down the tendon of the flexor carpi ulnaris. It passes un- der the palmar aponeurosis, on the inside of the os pisiforme, reaches the base of the metacarpal bone of the little finger, and begins to form the Superficial Palmar Arch. This arch lies above the tendons of the flexor sublimis perforatus, immediately beneath the palmar aponeurosis. It crosses the metacarpal bones betwixt their bases and the middle of their bo- dies. It begins at the root of the little finger, and ter- minates at the root of the thumb, in inosculations with the branches of the radial artery. The convex side of the arch is turned towards the fingers, and sends off five branches. (1.) A branch to the muscles and inner edge of the little finger. (2.) Ramus digitalis primus, or the first digital ar- tery, which runs along the space betwixt the two last metacarpal bones, and bifurcates into two branches, one to the outer side of the little finger, and the other to the inner side of the ring-finger. (3.) The second digital artery, which bifurcates in a similar manner, and supplies the outer edge of the ring-finger, and the inner side of the middle finger. 296 (4;) The'third digital artery, which is distributed to the outer edge of the middle finger, and to the inner side of the fore-finger. (5.) The ramus pollicis ulnaris is the last branch of the ulnar artery, and is sent to the muscles of the thumb. From the concavity of the arch are sent off the in- terosseous arteries of the palm, small twigs which supply the deep*seated parts, and perforate betwixt the metacarpal bones to the back of the hand. The branches of the ulnar artery, in its course along the fore-arm and wrist, are the following. (1.) The Recurrent Arteries are two in num- ber. They are sent off from the ulnar artery imme- diately below the elbow, sometimes in one common branch, which subdivides. The anterior recurrent runs over the fore-part of the inner condyle ; the pos- terior recurrent passes over the back-part. These ar- teries inosculate with branches of the brachial. (2.) Twigs to the muscles of the fore-arm. (3.) A. Dorsalis Carpi is sent off from the ulnar artery a little above the wrist to the back of the hand. Twigs are also given off to the annular ligament and neighbouring parts. (4.) A. Palmaris Profunda is sent off from the ulnar artery, where it descends on the inside of the os pisiforme. It passes into the flesh at the root of the little finger, and inosculates with the termination of the deep-seated palmar arch of the radial artery. 3. Arteria Interossea (or Interossea Commu- nis). This artery is generally sent off from the ulnar. It immediately divides into two branches: (1.) The external or posterior interosseous artery 297 is the smallest branch. It passes through the upper part of the interosseous ligament, to supply the mus- cles on the posterior part of the fore-arm. It sends off the A. Recurrens Interossea, which ramifies on the middle of the back-part of the elbow-joint. (2.) The internal or anterior interosseous artery descends close upon the middle of the interosseous li- gament, betwixt the flexor longus pollicis and flexor profundus perforans, giving twigs to thl adjacent muscles. Arriving at the upper edge of the pronator quadratus, it perforates betwixt the radius and ulna to the back-part of the arm, and spreads its extreme branches on the wrist and back of the hand. VEINS. The cutaneous veins have been already described. The brachial artery is accompanied by two veins, named Vens Comites, or Satellites. These receive branches corresponding to the ramifications of the ar- tery. NERVES. In the dissection of the axilla, we demonstrated the great axillary plexus, and traced its two first branches, the external scapular and circumflex nerves. The distribution of the five remaining branches of the plexus must now be described. (3.) The External Cutaneous Nerve (Mus- culo-cutaneus, or Perforans Casserii) is the third branch of the axillary plexus. It passes through the belly of the coraco-brachialis muscle. After its pas- sage, it continues its course obliquely across the arm, betwixt the Biceps flexor cubiti and the Brachialis internus. It gives twigs to these muscles, and appears 298 as a superficial nerve on the edge of the supinator lon- gus. It runs over the outer condyle, and is distributed to the integuments on the outside of the fore-arm, and back of the hand. (4.) The Radial (or Median) Nerve accompa- nies the brachial artery to the bend of the elbow, and is contained in the same &heath as the artery. In its passage down the arm, it lies before that vessel, but at the elbow is situated on its inside. It gives off no branches until it has sunk under the aponeurotic ex- pansion of the biceps flexor. Here it distributes many nerves to the muscles of the fore-arm, to the prona- tor teres, flexor carpi radialis, the flexors of the thumb and fingers, and the pronator quadratus. The trunk of the nerve perforates the pronator teres, passes betwixt the flexor digitorum sublimis and flexor profundus, and continues its course betwixt these muscles down to the wrist. Near the wrist it becomes more superficial, lying amongst the ten- dons of the flexors, and before it descends under the annular ligament, sends a superficial branch to the integuments and short muscles of the thumb. The nerve itself passes with the flexor tendons of the fingers under the annular ligament of the wrist, emer- ges from these tendons, and appears on their outside, near the root of the thumb. It ramifies superficially in the hand, setting off four branches. The first branch passes- to the thumb; the second to the side of the fore-finger next the thumb; the third divides into two nerves,;of which one passes to the inner side of the fore-finger; the fourth also subdivides into two, to the inside of the middle finger, and outer side of the ring-finger. These nerves pass before the flexor 299 tendons, but behind the superficial palmar arterial arch, to reach the fingers. (5.) The Ulnar Nerve descends along the inside of the arm. It is at first situated immediately under the integuments, but below the middle of the arm is tied down by the intermuscular ligament which passes to the inner condyle of the humerus. The nerve be- comes here more deeply seated -r it runs between the inner condyle in the hollow behind it and the olecra- non, and in the flesh of the brachialis externus, or third head of the triceps extensor. After passing the condyle, it continues its course betwixt the two heads of the flexor carpi ulnaris, till it reaches the ulnar ar- tery. It then accompanies the ulnar artery, lying on its inside, and running along the fore-arm betwixt the flexor ulnaris and flexor digitorum sublimis. It sends twigs to the neighbouring muscles, and, when arrived near the wrist, divides into two branches. 1. The Smaller Branch, called Ramus Posticus, passes un- der the tendon of the flexor carpi ulnaris, and over the lower end of the ulna, to be distributed to the back of the hand, and of the little and ring fingers. 2. The continued trunk of the nerve passes, on the inside of the ulnar artery, over the annular ligament of the wrist. It passes under the palmar aponeurosis, and divides into three principal branches. The first sup- plies the integuments and muscles on the ulnar edge of the hand, and the inner side of the little finger. The second is distributed to the outer side of the little finger, and inner side of the ring-finger. The third branch passes deep under the long tendons, accompa- nies the deep-seated palmar arch, and terminates in the short muscles of the thumb and fore-finger, com- municating with the radial nerve. 300 (6.) The Muscular or Spiral Nerve (Radial •f some anatomists) passes from the axilla behind the os humeri, making a spiral turn round the bone to reach the outside of the arm. It first descends between the brachialis externus and short head of the biceps extensor cubiti, accompanying the arteria profunda humeri superior, and passing deep into the flesh of the arm. Before it makes this turn, it gives branches to the muscles, also a cutaneous branch, which descends on the inside of the arm. From the back-part of the arm the great trunk of the nerve is reflected spirally forwards. It is seen emerging be- twixt the supinator longus and brachialis internus, seated deep and close to the bone. It descends be- twixt these muscles, keeping close to the edge of the supinator longus. Immediately after passing the fold of the arm, it sends off a nerve, which descends, su- perficial, upon the radial edge of the fore-arm, as far as the wrist; and, at this point, the trunk of the mus- cular nerve divides itself into two branches. The first, a large branch, perforates the supinator brevis, and supplies the extensor muscles of the hand and fingers. The second branch accompanies the supi- nator longus down the fore-arm, and near the wrist turns under the tendon of that muscle, over the edge of the radius. It then divides into several branches, which ramify on the back of the wrist, thumb, and fore-finger. (7.) The Internal Cutaneous Nerve descends superficial, along the inside of the arm and fore-arm. It was described among the cutaneous nerves of the arm. APPENDIX: CONTAINING FHE RUYSCHIAN ART AND METHOD OF MAKING PREPARATIONS TO EXHIBIT THE STRUCTURE OF THE HUMAN BODY. cc THE INJECTING TRAY AND ITS APPENDAGES, For the purpose of facilitating the process of Quicksilver In- jections, and preventing the loss of Quicksilver, which is constantly occasioned by the old method. EXPLANATION OF THE PLATE. A. The tray. • This should be made of mahogany, about three-quarters of an inch in thickness, and the several parts should be joined together with screws ; every joint should be made perfectly water-tight, and the inside painted black, as this is much more favourable for seeing the fine parts of white membranes lying upon it, and the quicksilver flowing through the minute ramifications of their vessels. The ma- chine being made in this form, is intended to be occasionally filled with water, for the purpose of injecting broad and flat parts, which require to be so managed as to prevent their drying, and to which the common jar, represented in the plate, is not adapted, as placenta;, large portions of mesentery and intestine, female breasts, &.c. B. An iron pipe with an ivory plug, for the purpose of drawing oft" the water and quicksilver remaining in the tray after the injection is finished ; it is made of iron, that it may not be affected by the quicksilver. C. C. The right and left sides of the tray, cut down to form a rest for the arms, whilst the hands are employed upon a preparation at the bottom of it. The front D, is also made considerably lower than the sides, for the more convenient management of the preparation. The bottom of the tray should be about twenty inches square ; the front about three inches high, and the sides four and a half: the clear dimen- sions on the inside are here meant. E. A ledge in one corner, for the convenience of fixing the bottle containing the quicksilver ; it has a hole sufficiently large to receive the bottle, which is let through, and stands on the bottom of the tray to preserve it from any accident, which it is very liable to from its weight. F. F. Two uprights ; the foot of each fixes in two square staples, within the right and left sides of the tray, and ought: to be about twenty-four inches high. G. The cross-piece, the ends of which slide up or down in the mortise of the uprights, and are fixed to any height, by means of pins passing through them and the ends of the cross- piece, to keep them steadily fixed to each other. In the lower edge of this cross-piece is fixed several small hooks, from which may be suspended one or more injecting tubes. H. Is a glass jar containing water, in which is immersed a hand, with the quicksilver injecting pipe fixed in the artery, as in the process of filling the vessels. The band is suspend- ed by a string from the edge of the jar. 1U APPENDIX. PREPARATIONS OF THE VISCERA. JL HE various parts of the body may be preserved in a heal- thy state, either to exhibit their form or structure, or to com- pare them with morbid parts. GENERAL OBSERVATIONS. 1. When removed from the body, and the useless parts dis- sected away, the part to be preserved is to be soaked in wa- ter, in order to get out the blood. 2. When it is necessary to give parts their natural form, which is lost by macerating, put them into a saturated solution of alum, retaining them by any means in the required form, until they become hardened. If it be a hollow part, as the stomach, bladder, &c. fill it with, and immerse it in, the solu- tion. 3- When an opening is to be exhibited, as that of the ure- ter, the bile-duct, the lacunae of the urethra, Stenonian duct, Fallopian tube, &c. introduce a bristle. After this manner preserve the uterus and its appendages, cutting open the va- gina and cavity of the uterus, the bladder, intestine, stomach, heart in the pericardium, liver, spleen, kidney, &c. &c. 4. All preparations of the brain are best hardened in a sa- turated solution of corrosive sublimate. 5. The parts are to be suspended in proof spirit by raw silk, in a tie-over bottle, and covered with bladder, taking care to exclude all air. When dry, varnish the bladder with muci- lage of gum arabic several times ; then put a sheet of thin lead over, and varnish its edges with mucilage ; and lastly, tie another bladder over, and give it a coat of common spirit var- nish, in which lamp-black, or other colouring matter, is mix- ed. PREPARATIONS OF MORBID PARTS. All morbid parts should, immediately after their removal from the body, be put into rectified spirit of wine for a day or two, and then preserved in proof spirit. These prepara- tions foul a great quantity of spirit, and should therefore be kept in stopper glasses, from which the spirit can easily be removed, and fresh put in, until the preparation ceases to foul the spirit, when it may be put into a tie-over bottle. APPENDIX. SOS PREPARATIONS MADE BY MACERATING. Preparations obtained by this process are very various GENERAL OBSERVATIONS. 1. Let the water be frequently changed, until it is no lon- ger coloured with blood, but never after the blood is steeped away. 2. Let the macerating pan be placed in a warm place, to facilitate putrefaction. 3. The macerating pan should never be in a cold place, for the spermaceti-like conversion of the soft parts will be form- ed, and the bones spoiled. 4. The soft parts surrounding bones are a long time before they detach themselves from the bones. 5. Bones, when macerated, should be exposed to the sun's rays, and frequently wetted with clean water, or they may be bleached with the diluted oxygenated muriatic acid. BONES. Bones are macerated to be preserved whole, or they are sawed to expose their internal structure. Bones of the head. Pat the whole head, without disturbing the flesh or brains, into the pan. When sufficiently macerat- ed, all the soft parts will come away with the periosteum ; then detach the vertebrae, and wash out the biain. Bones are separated from each other by filling the cranium with peas, and putting it into water. The same method is to be adopt- ed with other bones. Bones in general, for structure. Divide the femur into two halves : the os innominatum, the petious portion of the temporal bone, the parietal bones, &c. these, when macerated, wilt exhibit the compact, the spongy, laminated, and reticu- lar substance of bones. A FOETUS. Cut carefully away the fatty substance enveloping a fatus, but do not cut any of the cartilages. Steep out its blood, and macerate. It should be frequently looked at, and taken out when the flesh is all destroyed, before the cartilages are sepa- rated. The following preparations are obtained in this way : 1. The superior extremity, to show its bones, the progress of ossification, and the cartilage to be formed into bone. 2. The lower extremity, to expose the same circumstance. 3. The spine, which forms a beautiful preparation. 4. The pelvis, not less elegant. Preservation. The above all to be preserved in proof spirit cc 2 306 APPENDIX. CUTICLE. The cuticle of the hand and foot may be separated by mace- ration ; the former is called chorotheca, the latter pcdatkeca. The arm and foot of a large foetus are to be preferred ; they are first to be well washed with a soft spunge in soap and water. Preservation. Suspend them in proof spirit; first tie the part by which they are to be suspended, then put them into the bottle with the spirit, and gently pour some spirit into the cuticle, to distend it like a glove or stocking. INJECTING INSTRUMENTS. The celebrated Dutch anatomist, Ruysch, first invented the art of injecting animal bodies. There are three kinds of apparatus used in making injected. preparations. The one for the coarse and fine injections, and the minute injection ; the other for injecting with quicksilver; and the third, called the oyster, syringe, for injecting minute preparations with the minute injection only. The first consists of a brass syringe made for the purpose, of various sizes, from one carrying six ounces to one sufficient- ly large to hold two pounds. The point of these syringes is adapted to the pipes into which it is to be affixed. To this syringe belong a stop-cock, and a great variety of pipes. The instrument for injecting quicksilver consists of a long glass tube, at whose end is fixed, by screwing in, a steel pipe, the end of which is extremely fine. The oyster syringe is similar to the large syringe, except in size. It is so small, that when the syringe is in the hand, and full, its piston may be commanded by the thumb of that hand to throw its contents into any preparation in the other hand. The pipe affixed by being screwed to the end of this syringe is nearly as small as that belonging to the quicksilver tube. These instruments are always to be had at the surgical in- strument makers. INJECTIONS. The injections employed for anatomical purposes are of four different kinds : coarse, fine, minute, and mercurial. COARSE INJECTIONS. Red. Yellow bees' wax, sixteen ounces—the palest resin, eight ounces—turpe; tiie,varnish, six ounces, by measure- finely levigated vermilK$R^fcb.ree ounces. APPENDIX. -. :M7 Yellow. Yellow bees' wax, sixteen- ounces—pale resin, eight ounces—turpentine varnish, six Ounces—king's yellow, two ounces and a half. White. Fine virgin's wax, sixteen ounces—pale resin, eight ounces—turpentine varnish, six ounces—best flake white, five ounces and a half. Pale blue. Fine virgins' wax, sixteen ounces—pale resin, eight ounces—turpentine varnish, six ounces—best flake white, three ounces and a half—fine blue smalt, three ounces and a half. Dark blue. Fine virgins' wax, sixteen ounces—pale resin, eight ounces—turpentine varnish, six ounces—blue verditer, ten ounces and a half. Black. Yellow bees' wax, sixteen ounces—pale resin, eight ounces—turpentine varnish, six ounces—pure lamp-black, one ounce. Green. Yellow bees' wax, sixteen ounces—pale resin, eight ounces—turpentine varnish, six ounces—levig-ated crystalliz- ed verdigrise, four ounces and a half— best flake white, one ounce—levigated gamboge, one ounce. Liquefy the wax, resin, and turpentine varnish over a slow fire, in an earthen pipkin ; then add the colouring matter, hav- ing previously mixed it in another pipkin, with a very small quantity of the melted composition. Stir the whole well toge- ther with a wooden pestle, so that the colouring ingredients may be intimately and smoothly blended; .place the whole again over the fire, and, when they have acquired their due heat, the injection will be fit for use. FINE INJECTIONS. Brown spirit varnish, white spirit varnish, ©f each four oun- ces—turpentine varnish, one ounce. These are to be put together in an earthen pipkin, over a slow fire, until they have acquired the necessary degree of heat. To make it of a red colour, put one ounce of finely levi- gated vermilion into another pipkin, and gradually add the heated materials, stirring the whole with a wooden pestle, that the colour may be equally diffused. One ounce and a quarter of king's yellow—two ounces of best flake white—one ounce and a half of fine blue smalt, with one ounce and a quarter of best flake white—four ounces of blue verditer—half an ounce of pure lamp-black—are the pro- portions for the various colours to the quantity of ingredients ordered above. MINUTE INJECTIONS. The size, which forms the vehicle to the colouring matter in these injections, is made in the^following manner : 308 APPENDIX. Take, of the finest and most transparent glue, one pound, break it into small pieces, put it into an earthen pot, and pour on it three pints of cold water, let it stand twenty-four hours, stirring it now and then with a stick; then set it over a slow fire for half an hour, or until all the pieces are perfectly dis- solved ; skim off the froth from the surface, and strain it through a flannel for use. Isinglass and the cuttings of parchment make an elegant size for very particular injections ; and those who are not ve- ry nice may use the best double size of the shops. Red. Size one pint—Chinese vermilion, two ounces. Yellow. Size, one pint—king's yellow, two ounces and a half. White. Size, one pint—best flake white, three ounces and a half. Blue. Size, one pint—fine blue smalt, six ounces. Green. Size, one pint—levigated crystalized verdigrise, two ounces—best flake white, levigated gamboge, of each eight scruples. Black. Size, one pint—lamp-black, one ounce. GENERAL OBSERVATIONS. 1. All injections are to be heated to such a degree as not to destroy the texture of the vessels they are intended to fill; the best criterion of this degree of heat is dipping the finger into the injection. If the finger can bear the heat, the texture of the vessels will not be hurt. 2. All the coloured materials should be as finely levigated as possible, before they are mixed with the injection. 3. Great care should be taken lest the oily ones boil over, or bubble; and that the heat be gentle, otherwise the colour will be altered. 4. They should be constantly stirred, lest the colouring ma- terial, which is much heavier than the vehicle, fall to the bot- tom. 5- The instrument to stir them with should be a wrooden pestle, and there should be one for each colour. 6. A large tin pan to contain water, with two or three les- ser ones fixed in it for the injections, will be found very use- ful, and prevent all accidents, and the colour from spoiling, when on the fire. PREPARATION MADE WITH COARSE INJECTION. The bloc.d-vessels are mostly filled with coarse injection, and the paits dissected, to show their courseY and when the APPENDIX 309 anatomist wishes to exhibit the minuter branches, the fine in- jection is to be thrown in first, and followed by the coarse. GENERAL OBSERVATIONS. There are several circumsta'nces to be observed in injecting with the fine and coarse injections, which are applicable to every part into which they are thrown ; these are— 1. The part to be injected should be freed from its blood as much as possible, by steeping it for several hours in warm water, and repeatedly changing it. 2. Having emptied the part of its blood, the pipes are to be fixed in their proper vessels, and all other vessels to be tied with a ligature. 3. The heat of the water is then to be gradually increased to the same temperature with the injection to be thrown in. 4. The injecting syringe should be steeped in the water with the part to be injected, until wanted. 5. The injection being finished, and the subject cold, remove the pipes, and tie up the parts they were in When- ever a vessel is open, by accident or otherwise, be sure to se- cure it by a ligature, or cover it with a piece of thin and moist bladder, or the injection will always be oozing out. 6. The parts dissected and dried are to be varnished twice with copal or hard varnish, first washing them free from grease with some soap lees, and well drying them again. BLOOD-VESSEL SUBJECT. Select an emaciated subject, between the age of two and fourteen years. Preparation. Make an incision through the integuments the whole length of the sternum ; then, with a saw, divide the sternum longitudinally into two equal parts ; introduce a dis- secting knife under the divided bone on each side, separate it from the mediastinum, and lay open the thorax, by bending back the two portions of the sternum and the cartilages of the ribs: an incision is then to be made" into the pericardium, and the left ventricle of the heart, and a large pipe introduced into the aorta, and secured by a ligature. The subject is next to be put into warm water, and gradually heated. The time generally required to heat the whole subject is four hours, in a large body of water. If thevekis are to be injected, three more pipes are requir- ed : one to be put into the angular vein, at the corner of the orbit; another into a vein as near the fingers as possible ; and the third into a vein as near the toes as possible. 310 APPENDIX. Injection. The subject and injection beingproperly heated, threw the coarse red injection into the heart pipe, which will fill the arterial system; and then the coarse yellow injection into the head pipe first, and next into the pipes of the extre- mities. The subject, when injected, should be put into cold water, with its face downwards. Dissection. Open the abdomen by an incision from the ster- num to the umbilicus, and from thence to each ilium. Cut away the abdominal viscera, the stomach, spleen, and intestines, leaving- the mesenteric vessels as long as possible : dissect. away the liver, leaving the vena ports and hepatic artery as long as possible. This done, dissect away the fat and cellular membrane from the vessels; secure the mesenteric vessels in an arborescent form on a piece of pasteboard. The kidneys, urinary bladder, uterus, audits appendages, are to be preserv- ed and dried in their situations. From the thorax are to be removed, the lungs and heart, or the latter may remain. The integuments being carefully dissected from the sternum, it is to be bent back, and kept in that situation, to expose the inter- nal mammary arteries. The dissecting away the skin is next, in order to exhibit the muscles, and expose the arteries and veins. The skin should only be removed from time to time to carry on the dissection, and never more than that covering the part to be dissected; otherwise the parts from which the skin is removed will become dry, and the dissection be spoil- ■ ed. In dissecting the arteries and veins, the dissector will find /no difficulty, if he proceeds cautiously from the larger trunks towards.their extremities. The brain is to be removed by sawing away a large portion of the bone on each side of the longitudinal sinus of the dura mater. The cheeks should be pushed out by introducing horse hair into the mouth. Drying. When dissected, or before, the subject should be hung up by the head in a frame: one arm is to be placed at a little distance from the side, and the other turned up over the head, with the palm of the hand in front; the legs at a little distance from each other, and kept in these postures b} pack- thread. Should any muscles obstruct the sight of the arte- ries, they are to be separated to a proper distance by pieces of wood. This done, expose it to a current of air, in a place where it cannot get wet; and if the weather be moist, remove, from time to time, all moisture, by a soft spunge. Preservation. Varnish it several times, and keep it in a dry place, and in a proper case, with a glass front and back. A HEAD, FOR ARTERIES AND VEINS. Choose an emaciated head of an adult, separated from the body, by a transverse section, about the sixth or seventh ver- tebra. . APPENDIX. 311 Preparation. Put a pipe into each carotid, or, what is better, one pipe with a bifurcation ; remove a portnn of b*ne over the longitudinal sinus of the dura mater, about the middle of the parietal bones, and secure a pipe in the longitudinal sinus, pointed towards the occiput. Put the head into warm water, to soak, pressing the blood occasionally out of the external and internal jugulars. Then tie up the jugular veins and vertebral arteries, and all the small vessels. Injection. Into the carotids throw the red injection, and the yellow, or dark blue, into the pipe in the sinus of the dura mater. The former will fill the arteries, the latter the ^ ems Dissection. Follow the course of the larger trunks, dissect out the globes of the eyes, and remove, with a fine saw, the portion of the jaw-bone behind the last molaris, to show the course of the internal carotids. To prepare the whole head, a portion of the cranium must be removed, by sawing on one side of the longitudinal sinus of the dura mater from the frontal sinus to the horizontal spine of the occipital bone, and then sawing horizontally above the ear, from one extremity of the former incision to the other. The dura mater should be re- moved with a pair of scissars, the brain carefully washed out, and the tentorium and falx preserved. It is better to make a perpendicular section of the head, a little to one side of the sagittal suture, through the nose, foramen magnum, and verte- brae; and thus prepare each side. The course of the cervical artery is to be shown by dissecting away the muscles, &c. from between the transverse processes. Preservation.. Varnish it several times, and keep it in a glass case, suspended; or fix it by the*neck, and cover it with a glass bell. AN ARM, FOR ARTERIES AND VEINS, Remove the superior extremity from the trunk, by separat- ing the clavicle from the sternum, raising it, and passing the knife under it to the articulation, including the greater part of the pectoral muscle. Then cut under the scapula, so as to re- move with the arm the clavicle, scapula, and subscapularis muscle. Preparation. After soaking it in warm water, force out the blood from the veins, by pressing the extremity from the fin- gers toward the shoulder. Fix a pipe in the axillary artery, and another in the largest vein on the back of the hand; some warm water may be injected into the vein, so as to wash out the blood; and, when pressed out, the axillary vein should be tied. Tie any muscular branches that may be gaping. Injection. Red injection may be thrown into the artery, and yellow, or dark blue, into the vein. Dissection. This is very simple; it requires only the remo- 312 APPENDIX. val of all the cellular and fatty membrane, and exposing the course of the vessels. Tie up the limb by the clavicle Preservation. When varnished, keep it in a cool and dry place. A LOWER EXTREMITY, FOR ARTERIES AND VEINS. Having removed the contents of the abdomen, make a sec- tion through the symphysis of the pubis, and the ligaments connecting the ilium and sacrum, so as to remove one side of the pelvis. Preparation. Fix a pipe in a vein as near the toes as possi- ble, and another in the iliac artery. When the hmb has been well soaked in warm water, press out the blood from the veins, or throw in some warm water at the venal pipe ; but carefully press it out again, and tie up the iliac vein. Se- cure all divided vessels. Injection. Blue injection, or yellow, may be put into the vein, and red into the artery. Dissection. Expose the course of the artery and veins, particularly the profunda of the thigh. THE GRAVID UTERUS, FOR ARTERIES AND VEINS. The gravid uterus, or the uterus soon after it has expelled the foetus, may be injected, to show its large and tortuous ves- sels. It may be injected whilst in the body : but this is always attended with much difficulty, and never succeeds so well as when removed from the body. Therefore separate the sper- matic and hypogastric vessels as far from the uterus as possi- ble, and cut out the uterus with the bladder, vagina, and ex- ternal parts of generation. Preparation.^ Put a pipe in each spermatic artery, and each hypogastric, and also one into each spermatic and hypogastric vein ; so that, at least, there will be four pipes for arteries, and four for veins, necessary. Be very careful that all the di- vided vessels be secured by ligature, which only can ensure success. Injection. Red and yellow are mostly preferred; the former for the arteries, the latter for the veins. Be careful that the red be thrown into all the arterial pipes, and the yellow into the venal; and, to prevent mistakes, it will be better to have the pipes of the veins different from those of the arte- ries. Dissection. Distend the vagina and uterus with horse hair,, either by introducing it through the vagina, or, if the foetus APPENDIX. 3tS be in it, by a perpendicular section through the anterior parie- tes, which is to be sewed up again. Then dissect away all loose cellular structure and fat, preserving the round and broad lig-aments, and Fallopian tubes. Should the foetus be in the uterus, an incision should be made, as above directed, except the placenta be adhering there, which is known by the great number of vessels, and then on the opposite side, ?md through the membranes, to remove the child ; cut the umbilical cord close to the foetus, and fix a pipe in one umbilical artery, and another in the umbilical vein ; the latter, carrying arterial blood, should be filled with red injection, and the artery with vellow; the cord is to be laid round the placenta. Preservation. When well varnished, suspend it in a case, with a glass front and back. A PLACENTA, FOR ARTERIES AND VEINS. This is perhaps the easiest preparation to make with coarse . injection, and should, therefore, be the first attempt of the student. - . Preparation. Fix a large pipe in the vein, and a small one in one of the arteries. The difficulty usually attendant on getting the pipe into the artery is obviated in a great mea- sure by introducing the point of the scissars into these vessels, and slitting them down for about half an inch, then spreading the artery open upon the fore-finger, and keeping it so by pressure with the thumb, by which the pipe m:>.y be carried in without difficulty. A ligature should be passed round each pipe with a needle, taking care not topuncture any of tll6 VCSSCls. Injection. The usual colours are to be selected; but in- stead of throwing the yellow into the vein, it should be push- ed into the artery, for the artery here performs the function of a vein, and -i ice versa. When there are two placentae, there should be different colours used. Dissection. The spongy substance is to be carefully dis- sected away from the injected vessels, the placenta soaked in cold water, to get rid of its blood, and then dried, curling the cord around it; and should the membranes not be much torn they may be distended with curled hair over it. Preservation. Varnish it well; fix its bottom-la a case with a glass top. THE HEART, IN SITU; WITH THE HEAD AND ADJACENT VESSELS. For this purpose choose the head of a young subject, or an adult whose heart is free from fat. The liver, stomach, -pleen &c. are to be removed from the abdomen, and the 314 % APPENDIX. aorta divided just as it gives off the coeliac artery. The in- cision into the chest should be carried through the integu- ments, from the trachea to the ensiform cartilage, the sternum sawed through, and bent one half on each side, from the ex- tremity of the cartilages nearest the ribs; then divide one of the pulmonary veins as near as possible to the lungs, and re- move a portion of bone over the longitudinal sinus of the dura mater. Preparation. Having well soaked the parts in warm water, and squeezed the blood from the heart and vessels, by the in- ferior cava and pulmonary vein, put a pipe into the longitudi- nal sinus of the dura mater, pointed towards the occipital bone, another into the pulmonary vein, a third into the vena azygos, and one into the receptaculum chyli, or thoracic duct. Tie up carefully the aorta and the vena cava inferior, and put a strong ligature around the middle of each arm. Injection. Three colours are required;—one for the arteries, which should be red; another for the veins, which may be yellow or blue; and the third for the thoracic duct, which should be white, to imitate chyle. -Throw the red injection into the pipe in the pulmonary vein, which will fill the left au- ricle, ventricle, aorta, and all the arteries. The pipe in the head is for the yellow injection; by this will be filled the veins of the bead, face, neck, and chest, the right auricle of the heart, the right ventricle, and the pulmonary arteries. Should the vena azygos not be injected, the yellow injection is to be thrown into it. A small quantity of white injection is suffi- cient for the thoracic duct. Dissection. Remove the body by a transverse section at the last dorsal vertebra, then amputate the arms at their middle, sfiw away one side of the bones of the scull, and wash away the brain: then dissect away all the loose cellular membrane and fat, and expose the various parts in the best manner; dis- sect away the lungs, leaving tlie pulmonary arteries as long as possible. Preservation. This is, when well done, a valuable prepara- tion, and deserving of great care. Varnish it well, and pre- serve it in a square glass case. A FOETUS, TO EXHIBIT THE PECULIARITIES OF ITS CIRCULATION. For this purpose select a still-born foetus ; and, if possible, one that died from a flooding of the mother. Preparation. Dissect the umbilical vein from the arteries, about four inches from the umbilicus, and fix a pipe in it, taking care not to include the arteries. Throw warm water into this pipe, and wash out the blood, which will flow out by the umbilical arteries. Having drained away as much of the APPENDIX. 315 water as possible, tie a ligature very loose on the umbilical arteries. Injection. The foetus being heated, throw in gently any co- loured injection. The water will come away first through the umbilical arteries ; and, when the injection appears, make the ligature firm, to prevent its further egress. Dissection. The peculiarities in the foetal circulation are the umbilical cord, the ductus venosus, the ductus arteriosus, and foramen ovale. When the body is cold, proceed to the dissec- tion ; remove the head from the cervical vertebrae, the arms, with the scapulx, and pectoral muscles ; the inferior extremi- ty at the articulation with the pelvis, the whole of the parietes of the abdomen, leaving the arteries running to the cord by the sides of the bladder"; the anterior part of the thorax, with the sternum, cartilages, and part of the ribs, the integuments and muscles of the back. Next cut away the lungs, and re- move the pericardium ; keep the diaphragm in its place, and turn up the liver, so as to expose the ductus venosus. Some dissection and care is here necessary. Dissect away the sto- mach and intestines, and lay out the mesenteric vessels, dis- tend the bladder with air, and cut away any thing that may obstruct the view of the vessels. The foramen ovale cannot be exhibited. , Preservation. After having varnished it, hang it in a glass bell, with a hook at its top. PENIS. The penis may be injected, to show the two corpora caver- nosa, the corpus spongiosum, and glans, with the arter.es and veins For this purpose any healthy penis will do, but large ones are -enerally preferred. Having cut through the integu- ments and soft parts in the pelvis, in the direction the saw is to be passed, saw through the middle of each crista o. the pu- bis, straight down and through the ascending ramus 01 each ischium, close to their commencement, and thus remove t.ie pubis, with the bladler and external parts of generation. Preparation. Make an incision into either of the crura ol the corpora cavernosa, and into the bulbous V™\^\^ thra, as near to the prostate gland as possible ; ^*in hot water, and carefully press out the blood from evejy part li. Produce a probe along the vena magna ipsms penis, by an in- c sion at its root, to break down its valves : fix a p.pe meach of ihese incisions, and another in each vas deferens at its en trance Into the veViculs seminales, and secure all the divided ™Tie*»ion Four colours are necessary ; those generally pre- ferSTred, yellow, blue and whu. ^row *e red int. the corpus spongiosum, winch v, ,L distend tne gi 316 APPENDIX. low into the corpus caveimosum pipe ; the blue into the yCna magna ipsius penis; and the white into the vasa deferentia. Dissection. Inflate the bladder, dissect away all the soft parts, and keep the penis erect against the symphysis pubis. Preservation. In a covered box. TESTICLE. A testicle of an adult should be chosen free from disease, and great care is requisite in removing it from the body. First) enlarge the ring of the oblique muscle, push the testi- cle through from the scrotum, and separate its cellular con- necting substance ; then cut the spermatic artery and pampi- niform plexus as high as possible, and then the vas deferens. Preparation. When well soaked, press out the blood from the veins; put a pipe into the spermatic artery, and an- other into a vein ; and secure all other open mouths. Injection. Red is to be sent into the artery, and yellow or blue into the vein, which is without valves. Then fix the quicksilver tube in the vas deferens, and suspend it in water; this done fill it with mercury, and in twenty-four hours it may be removed to be dissected. Dissection. Cut away the tunica vaginalis, and the tunica albuginea, which requires great care: then remove all the cellular and adipose membrane, and dry it on a board previ- ously waxed. Preservation- In a common preparation glass, on a blue of green paper ground. THE SYSTEM OF THE VENA PORTyE. Remove the liver, spleen, stomach, and intestines altoge- ther, of a person whose mesentery is free from fat, cutting away at the root of the mesentery, behind the peritoneum. Preparation. Cut into a mesenteric vein, as near to the in- testine as possible, and secure it with a ligature passed around it with a needle, taking care not to wound any other vein. Inject warm water, and let it again run out by the di- vided vessels. Drain its water off", and secure all the veins, the hsemorrhoidal especially. Injection. Throw any colour into the pipe, which will pass into the splenic, mesenteric, and internal haemorrhoidal vein, and into the vena portae. Dissection. Remove all the soft parts ; the stomach, spleen, and intestines ; cutting the vessels as long as possible, and dry them in the best manner, either attached to the liver, or dissect away the liver from the vena portae, taking care to preserve some of its ramifications. APPENDIX. Preservation. In a covered box. HEART. The heart is mostly injected out of the body, to show its common and proper vessels. For this purpose, choose a lean heart. Cut through the thoracic viscera immediately at the top of the thorax; divide the intercostal arteries by drawing the knife down the pleura, over the ribs beyond their origin, separate the vena cava inferior and aorta, in the abdomen, with the cavae hepaticse; and remove the thoracic viscera, with the portion of the diaphragm surrounding the vessels. Preparation. Soak the blood and coagula out of the cavities of the heart, and press the blood from the coronaries. Put a pipe into the vena cava superior, and another into one of the pulmonary veins. Then tie the lungs at their root, the vena cava inferior, the arteria innominata, the left carotid and sub- clavian ; and pass a ligature, with a slip knot, round the si- nus of the aorta, and secure all other open vessels. Injection. The common coloured injections, red and yel- low, only are wanted. Throw the former into the pulmonary vein, which will fill the left auricle, ventricle, aorta, and co- ronary arteries. The yellow, being sent into the superior ca- va, will distend the right auricle, coronary veins, right ven- tricle, and pulmonary artery. In order to fill the coronaries well, the injector must stop two or three times in the course of the process, to squeeze on the injection in them withhis nail; then heat the whole again, and throw in more, injec- tion. The preparation having cooled, a pipe is to be fixed at the bottom of the aorta, and some red injection, just hot enough to run through the syringe, is to be pushed along the aorta, an assistant throwing cold water on the intercostals, if the injection runs through them. Dissection. Cut away the lungs, pericardium, and all the soft parts. Preservation. Either in a covered box, or under a glass bell. STOMACH. INTESTINES. BLADDER. These are best injected with the whole subject, but may be removed and injected separately. , GENERAL OBSERVATIONS. J. The anatomist can oily succeed by having the prepara- tion constantly heated as he^is throwing in the injection. 2 The injection should be thrown in very gradually. 3. When injected, the part should be immediaiely immer- sed in cold water. d d 2 3,18 APPENDIX. PREPARATIONS WITH MINUTE INJECTION. BONES. The vascularity of bones is to be demonstrated, by throwing fine injection into an extremity, cutting out the bone when cold, separating it from all the soft parts, immersing it in wa- ter for a few days, to soak out the blood, and then putting it into a mixture of muriatic acid and water in the proportion of one ounce to a quart, for three or four months, adding about, every month, a drachm of acid. The limb of a ricketty child is to be chosen. Injection. Put a pipe into the largest artery of the extremi- ty, and throw gradually the red injection into it, fixing the stop-cock in the pipe. A FOETUS. Still-bom children, when injected with minute injection, af- ford a number of beautiful preparations. Preparation. No water should be thrown into the vessels- Fix a pipe with a stop-cock into the umbilical vein, and tie the arteries in the ligature. Injection. R^d injection is always chosen for this purpose ; and throw it in with great care, until the abdomen and skin all over become very tumid. First mucus comes from the nose and mouth, then the meconium from the anus, and often pure size. Dissection. Cut off the head from the shoulders, the arms below the shoulder joint, and the legs just below the acetabu- lum ; then preserve a small quantity of the integuments around the navel, and remove all the anterior parietes of the abdomen and chest, so as to exhibit the thoracic and abdominal viscera. Cut away the integuments and posterior part of the thee a ver- tebralis, to exhibit the medulla spinalis. Preservation. Soak out the blood, and preserve it in proof spirit, to show the viscera and iheir vascularity. From a well-injected foetus may be obtained the following preparations. 1. If the foetus be about seven months old, the membrana pu. pillaris. 2. If it be male of this age, the testicle in the abdomen, with the gubernaculum. 3. The vascular and radiated fibres of the par.etal bones. 4. The vascuiar membrane, including the teeth. 5. The viscera of the chest separate, if better injected than those of the abdomen, showing the vascularity of the lungs, tbymas gland, and heart. APPENDIX. 315 6. The stomach, which is to be inverted, to show its vascu- lar villous coat. 7. The intestines, which are to be separated from the mesen- tery, and inverted, to show their villous coat. 8. The glandula renales and kidnies together, to exhibit their relative size, and the lobulated structure of the kidney. 9. The uterus and its appendages, to show the long ovaria and plicae of the neck of* the uterus and vagina. 10. The external parts of the female organs of generation, to show the hymen. 11 A red portion of the skin, to exhibit its vascularity. 12. The medulla spinalis, to show its vessels, and the cauda equina. 13. The membrana tympani, to exhibit its vascularity. 14. The cavity of the tympanum, to show its vascularity, and that of the periosteum of its bones. 15. The vestibulum and cochlea, to show the membranous se- micircular canals of the former, with their ampullae injected, and the vascularity of the zona mollis. 16. The head, to show the natural appjjjfcce of the face, the papillae of the lips, tongue, &c. JM 17. The hand, to show its natural coloj^B Preservation. The above preparations^BIll to be well soak- ed from their blood, and preserved in t^V spirit of wine. 18. A portion of skin, freed of iyrzdwLf t0 show its **ascu- 19. The membrani tympani, to show itfvessels. £ 20. The heart, to show the foramen ovale, by distending the cavities with air ; and, when dry, cutting away the outermost sides of the auricles, and introducing a bristle. 21. Any large muscle, freed from its cellular membrane and fat, and driedjjx) show the vascularity of the muscle. Prtser^aTion. These are all to be dried, well varnished, and preserved in bottle*. , Some prefer putting them into spirit of turpentine jju^- looks best. Dissection. Cut away all the loose cellular membrane, bladder, and rectum, if there be any, from around the vagina, and cut it open along the middle of its superior part; con- tinue this incision on each side of the anterior part of the ute- rus, so as to exhibit the posterior surface of its cavity. Preservation. If the injection be successful, which it sel- dom is more than one time in ten, suspend it by the liga- ments, and preserve it in the proof spirit. AN ADULT HEAD. Separate the head as low as the last cervical vertebra from the shoulders. Preparation. Put a bifurcated pipe into the carotids. Se- cure the vertebral arteries and jugular veins, and all the divid- ed parts. Injection. The red injection is always preferred. From an adult head injected in this way may be made the following preparations: 1. The upper eyelid, to show the vascularity of Meibomi- us's glands. 2. The choroid membrane, exhibiting its vascularity. 3. The retina, suspended by the optic nerve, exhibiting its vascularity. 4. A section of the optic nerye, to exhibit the central artery. 5. The whole of the cerebrum, cerebellum, and medulla oblon- gata, Avith the pia mater; or, 6. The pia mater separated from the convolutions of the brain, to exhibit the intergyralprocesses and the tomentum cere- bri. 7- One half of the nostrils, to exhibit the vascularity of Schneider's membrane, and that of the membrane lining the antrum of Highmore. 8. The tongue, lying in the jaw, and suspended by the pa- latum molle, with the posterior fauces cut away, to show the epiglottis and glottis, the uvula and velum pendulum palati, the tongue, its papilla and excretory ducts, and the vascularity of the gums and sublingual glands. Preservation. The above preparations are to be soaked well in cola water, to get out all the blood, and then preserved in proof spirit. PREPARATIONS WITH QUICKSILVER. Mercury cannot be coloured by any substances; it must, therefore, always present the same silver colour. APPENDIX. 321 GENERAL OBSERVATIONS. 1. The part should always be injected in a proper tray, that the mercury may be easily collected. 2. A lancet, with a curved needle ready threaded, should be always at hand. 3. A bottle, whose neck is not so wide as to permit the quicksilver tube going to the bottom, when put into it. 4. When injecting, if any circumstance renders it neces- sary for the injector to put aside the tube with the mercury, it should be placed in the-bottle, the mercury remaining in it„ to be handy and prevent delay. 5. Injecting with mercury is always tedious, and frequent- ly unsuccessful. The parts exj. jsed must be kept moist, by sprinkling them with cold water. A SUPERIOR EXTREMITY. To inject the lymphatics of an arm, choose one from a dropsical subject, without fat; make an incision into the skin around the wrist, and seek diligently, with a magnifying glass, for an absorbent, into which the pipe is to be put, when the quicksilver will immediately run. The shoulder should now be placed considerably lower than the hand ; and, when the mercury runs out at the divided vessels in the axilla, tie them up, and also the lymphatic, into which the pipe was in- troduced. Then seek for another absorbent. When the mercury ceases to run in a lymphatic, tie the vessel, and seek for another. Dissection. Begin at the lymphatics, where the mercury entered, and trace them; removing every thing that ob- structs their view, but preserve the glands. AN INFERIOR EXTREMITY. The limb for this purpose should also be taken from a drop- sical person, and the same method adopted as with the supe- rior extremity, seeking as near to the toes as possible for the lymphatics. A PAROTID GLAND. Cut down upon the masseter muscle, and seek for the Sle- nonian duct, which is the excretory duct of the parotid. Tie the ouicksilver pipe in it, then fix the tube, and pour into it the ouicksilver; and, when it ceases to run, remove the tube and pipe, and tie the duct. Be particularly careful, in direct- ing away the gland., not to cut it. 322 APPENDIX. Preservation. Dry it on a waxed board, and preserve it on a blue paper and pasteboard, in spirit of turpentine. LIVER. The lymphatics running on the peritoneal coat of the liver, and over the gall-bladder, make a beautiful preparation. The liver should be well soaked for several days, and the pipe put into the lymphatics of the suspensory and coronary ligaments, and the mercury forced along them, breaking down the valves with the nail, by pressing on the mercury. Secure the ves- sels at the portae of the liver, when the mercury gets there, and tie the lymphatics when filled. Should the anatomist's attempt to force the quicksilver beyond the valves be unsuc- cessful, he must fix upon the most minute obvious branch, and let it run its proper course. Preservation. Throw some coarse injection into the cavae hepaticae and vena portae, without heating the liver thorough- ly; inflate the gall-bl n;der, and dry the whole. Varnish it, and preserve ;t in the best manner under a glass bell, or, pre- serve the injected part in proof spirit, without any wax injec- tion. LUNGS. The superficial lymphatics of the lungs are to be filled from the part most remote from the root of the lungs. Preservation. Cut away the part on which the lymphatics are filled- Dry it on a waxed board, varnish it, and preserve it in a bottle, on a green or blue piece of paper; or preserve it in proof spirit, without drying it. HAND. Select the hand of an aged female (separated from the arm by a transverse section, three inches above the wrist) that has died of a lingering disease. Soak out the blood in warm wa- ter; fix the pipe in the radial artery, then add the tube, and pour into it the mercury. As the mercury appears in the other arteries and veins, take them up and secure them with ligatures. Should the mercury still escape from small branch- es, put a cord round the arm, and with a piece of wood tight- en jt, by twisting the wood, taking care not to prevent the mercury passing into the hand. Then suspend the hand in a glass filled with water, and suspend also the tube and quick- silver in the manner represented in the annexed plate, for a day or two, that the mercury ma}' get into the small vessels. When injected, remove the pipe, and tie, by a strong string, APPENDIX. 323 the fore-arm; put the hand into water, until putrefaction se- parates the cuticle. ; Preservation. Dry.it carefully, and varnish it; then fix the fore-arm in a pedestal of'plaister of Paris, and keep this beau- tiful preparation under a glass bell. LACTEALS. • Remove the mesentery and intestines, if the former be per- fectly free from fat, and let them remain several days in wa- ter, which should be frequently changed. Search for an ab- sorbent, on the intestine, into which introduce the quicksil- ver, which will run on to the glands in the mesentery, where it will stop. When the lacteals are filled, the preparation will be more elegant if red and yellow coarse injection be thrown into the mesenteric arteries and veins. Preservation. Spread the mesentery on a waxed board, in- flate a portion of the intestine, clear away all that is useless ; dry and varnish, and preserve it in a glass frame. CORRODED PREPARATIONS. These preparations are made by filling the vessels with coarse injection, and corroding the soft parts, so as to exhi- bit those vessels. GENERAL OBSERVATIONS. 1. The liquor for corrosion is to consist of three parts of muriatic acid, and one of water. 2. The liquor should be kept in a well-glazed earthen ves- sel, with a top to it, also well glazed. 3 The part to *be corroded should be carefully moved m and out of this liquor, as the slightest force may break the ' C4SeWhen corroded, the pulpy flesh is to be carefully washed awav, by placing it under a cock of water, the water flowing very slowly; or, in some instances, by squirting it away. 5 When the preparation is freed of its flesh, it should be fixed in the situation it is to remain in, either in a plaister of Piris pedestal, or on a flat surface. 6 If the flesh be not perfectly destroyed the preparation is to be returned to the* corroding liquor for a fortnight or month longer, or until it becomes pulpy. 324 APPENDIX. HEART AND LUNGS. These viscera, occupying less space in children than adults, are to be preferred. It is of no consequence whether they are fat or lean. The integuments should be cut from the fore part of the n.^ck; and the trachea, jugular veins, and ca- rotid arteries removed, and, with them, the viscera of the tho- rax, carefully separating the subclavian vessels from the cla- vicle, without injuring them, and dividing the axillary ves- sels and the cava inferior and aorta, just below the dia- phragm. Preparation- Soak the whole well, to free it of its blood, and press out all the fluids. fix a pipe in the inferior cava, and another in one of the pulmonary veins, t: king care not to injure the others, by tying it- Then secure the carotids, the jugulars, the axillary vessels, the vertebral artery, the inter- costals, the aorta, after it has formed its arch, the internal mammaries, and every vessel that can be found. Injection. Red and yellow are generally preferred, but red and blue are more proper, and inoie elegant. Throw the blue into the vena cava inferior, wiiich will distend the right auricle, the superior cava, the jugular veins, ,\nd great coro- nary vein, the right ventricle, and pulmonary arteries. The red injection will fill the left auricle and pulmonary veins, the aorta, subclavians, carotids, &c. Preservation. Great care is requisite in freeing the injec- tion from the pulpy flesh. When done, let the apex of the heart be placed immediately in a plaister of Paris pedestal, and cover it with a glass. If the pulmonary vessels are well preserved, it forms a valuable preparation. If one good pre- paration be obtained in ten trials, it will amply repay the ana- tomist. HEART. A fat heart will do for this purpose. Inject it as directed in page 317, and it put into the corroding liquor. Preservation. Lay it on some cotton, on a pedestal, and co- ver it with a glass. LIVER. The liver of a child is to be preferred to that of an adult, it occupying much less room : its vessels should be cut long, and with it the portion of the duodenum, perforated by the bile duct.„ . Preparation.. Fix a pipe into the hepatic artery, another APPENDIX. 325 into the vena ports, a third into the ductus communis chole- dochus, and a fourth into the vena cava hepatica. Injection. The four injections are to be red, yellow, dark blue, and light blue. First, throw the red injection into the hepatic artery, next the dark blue into the vena portae, then the light blue into the cavae hepatic ae, and, lastly, the yellow into the ductus communis choledochus. Preservation. Remove the pipes as soon as the injection will permit; and, when corroded, fix the trunks in the best man- ner possible, upon a proper pedestal: then wash away the flesh, dry it, and cover it with a glass. KIDNEY. Choose the kidney of an old drunkard. Cut the emulgent vessels close to the aorta and cava, and the ureter, very low; then remove the kidney, with its surrounding adeps. Preparation. Soak out the blood, and press out all the fluid. Fix a pipe in the emulgent artery, another in the vein, and a third in the ureter ; and tie up all the open-mouthed vessels. Injection. Red, blue, and yellow. First throw the yellow into the vein, then the red into the artery, and, lastly, the blue into the ureter. Preservation. Under a glass bell. The kidneys of different animals form a beautiful exhibition. A. FINLEY AND W. H. HOPKINS, Ab. 170, MARKET-STREET, «AVE LATELY PUBLISHED THE LIFE OF PETHAECH, COLLECTED FROM MEMOIRES POUR LA VIE DE PETRAROJJE, BY MRS. DOBSON. Rard magni errores nisi ex magnis ingeniis prodiere. Petrarch. Thrice happy minds that feel the power of friendship! Oft do the Muses, on a beauteous eve, The sky serene, and drowsy Nature hush'd, Vouchsafe celestial sounds to friendly ears, And raise their kindred minds with such Warm fancy, and ethereal forms, As 'scape the vulgar intellectual eye. Why need I launch into the praise of friendship I Friendship, that best support of wretched man! Which gives us, when our life is painful to us, A sweet existence in another's being. First American, from the seventh London edition. In two volumes, ornamented with two elegant engravings. To this edition is added a Translation of several of Petrarch's Sonnets and Odes, not in the London edition. THEY ARE PUTTING TO PRESS A DICTIONARY OF QUOTATIONS IN MOST FREQUENT USE, TAKEN CHIEFLY FROM THE LATIN AND FRENCH, But comprising many from THE GREEK, SPANISH, AND ITALIAN LANGUAGES, TRANSLATED INTO ENGLISH. With Illustrations, historical and idiomatic. BY D. E. MACDONNEL, OF THE MIDDLE TEMPLE. 1' He has been at a feast of languages, and stolen away all the scraps." Shakspeare. This compilation is intended chiefly for the assistance of the English reader (though it will very readily be perceiv- ed, that its utility is by no means confined to such), who, not being acquainted with other languages, is interrupted and embarrassed, even in the perusal of the daily journals, by such phrases as the following: bellum internecinum, —hors de combat,—statu quo,—tout ensemble,—sine qua non,—je ne sais quoi,—uti possidetis, 8cc. which, with many thousands of others of greater length, will be found in this work, and the reference is as easy as to any ab- struse word in Johnson's Dictionary. To such readers this work will give information not to be found elsewhere. *r. ./.. *tf?*tf* w •fc*5 »T». ■Zfr.