Biographical Sketch of the Author. Dr. WILLIAM B. TOWLES. William Beverley Towles. 
William Beverley Towles was born in Fluvanna County, Vir- 
gima, March 7th, 1847. He was descended from a family well- 
known in Virginia annals, his grandfather being Major Oliver 
Towles of the war of 1812, and his great-grandfather Colonel 
Oliver Towles of Revolutionary fame. His father was Hr. W. B. 
rowles, who practised extensively in Fluvanna and Cumberland 
c°unties. Reared in that famous country society of “ Old Vir- 
ginia”—the best form of civilization the world has known,—the 
noble qualities so conspicuous in the man were nourished and 
strengthened in the boy, and he bore through life untarnished 
the grand old name of gentleman.” 
The civil war began when he was fourteen years old. Even at 
this early age the martial spirit of his ancestors was aroused 
Within him, and in 1863, unable to longer endure inactivity, he 
leh home, without his father’s knowledge, to enter the army. On 
ac count of his youth, he was drafted into a reserve corps, which 
however, saw active service on several occasions. 
After Appomattox he returned to his father’s home to find it 
destitute and in need of his services. The best years of his boy- 
hood had been given to his country, so that the problem of educa- 
lon still confronted him. Difficulties to which a less vigorous 
soul would have succumbed, served but to stimulate his dauntless 
Spirit, and he applied himself with enthusiasm to his task. Ex- 
hausted by the day’s labor on the farm, he retired immediately 
after supper; at two o’clock in the morning the alarm clock awoke 
him, and from then until break of day he applied himself to his 
studies with incomparable diligence. “History and the Latin IV 
William Beverley Towles. 
Classics, Chemistry and Anatomy were swallowed in huge 
draughts.” So well did he prepare himself that when he entered 
the Medical Department of the University of Virginia, in 1868, he 
already “knew his text-books by heart.” In spite of a serious 
attack of typhoid fever, he obtained his degree in one year. 
From 1869 to 1872 he practised medicine in Missouri, where he 
made many friends. In the latter year he returned to the Univer- 
sity of Virginia, having accepted the position of Demonstrator of 
Anatomy, tendered him by Dr. John Staige Davis. This position 
he tilled until 1885, when, after the death of the gifted Davis, he 
was made Professor of Anatomy and Materia Medica. In 1886 
he was elected Professor of Anatomy at the University of Ver- 
mont. This elevated position gave greater scope to his talents, 
and at his death he was the most popular and effective teacher of 
Anatomy in America. 
He died September 15th, 1893, a few hours after delivering the 
first lecture of the session. During the progress of this lecture 
he suddenly became aware of the approach of death, but with 
characteristic bravery, he finished the lecture, and then returned 
home, where he laid down, and calmly and quietly awaited the 
end. To one who knew and loved him well, the most prominent 
of his many noble qualities was devotion to duty—duty to his 
country, to his family, his friends, his students, and especially to 
the great University, whose prosperity he so ardently desired. 
Having once determined that it was his duty to do anything, no 
earthly power could restrain him from its performance. Ho matter 
what difficulties might lie in the way, no matter how great the 
sacrifice of personal comfort or the physical and mental suffering 
involved, he marched, often rough-shod, and always with an invin- 
cible determination, where duty called. This devotion to duty was 
the ruling motive of his life, and as he had lived, so he died at the 
post of duty. William Beverley Towles. 
V 
Courage and candor were equally conspicuous in him. He had 
the highest sense of honor, and the utmost scorn for all that was 
low and dishonorable. A mean action on his part is not even 
conceivable. 
He was a man of intense feelings, a good lover, and a good 
hater. The friends lie had—and they were a host—he hound to 
him by the strongest ties. Loyal to the very core, true through 
evd report as well as through good report, in adversity as well as 
Prosperity, generous in the extreme, it was a great privilege to 
have his friendship. His manner, while he could he and often 
Was very stern, was naturally genial and cordial, and his hospitality 
eharniing to experience, so free from the faintest tinge of affecta- 
h°n. He delighted to have his friends about him, to make and 
0 receive sallies of wit and merry banter at times, or to discuss 
roportant subjects at others. His sense of humor was very keen, 
he dearly loved a good joke, and it made one happy to hear him 
Hugh. While often apparently brusque, he had a warm heart, 
easily moved by the misfortunes of others, and many a poor man 
h)-day mourns his death as that of his best friend. He was a 
Powerful man in all respects; there was no weakness in him, and 
his strong character left its impress on all who came under its 
“This earth that bears thee dead 
Bears not alive so stout a gentleman.” 
His mind was singularly active, always on the alert for knowl- 
°dge? quick to apprehend, and tenacious of its grasp. What he 
Saw, he saw distinctly; he had few doubts. His knowledge was 
l-d’eat, well classified, and always ready for use. 
Hut his most distinctive mental faculty was a wonderful power 
quick and accurate observation, and the mental pictures thus 
obtained were never forgotten. It is characteristic of him that 
''Chile preparing himself for the study of medicine he memorized, William Beverley Towles. 
not the descriptions, but all the diagrams of a text-hook of Anat- 
omy. 
He possessed great physical strength, and industry in propor- 
tion. So arduous was his self-imposed labor as Demonstrator of 
Anatomy that even his powerful frame was often exhausted to 
such an extent that he could not reach his home without resting 
by the wayside. 
He was a horn teacher, possessing in the highest degree the 
happy faculty of imparting his knowledge to others. His career 
made an epoch in the teaching of Anatomy in this country. His 
towering form and noble presence, his piercing eye, his intense 
enthusiasm, and the vivid and striking language in which his state- 
ments were made produced an impression never to be forgotten, 
and infused a vigorous interest into what is so often regarded as 
an uninteresting subject. He had,, therefore, the orderly attention 
of his students, winning the admiration and respect of all, and the 
love of those who had the fortune to know him. His method of 
teaching was based on the fact that useful and abiding knowledge 
of Anatomy must he obtained by a practical familiarity with the 
structures themselves, and not from representations or descriptions 
of them. It was his boast that he made scarcely a single state- 
ment which was not demonstrated to each student individually. 
Every student was required to frequently dissect, and the principal 
truths were repeatedly demonstrated to him by a competent in- 
structor ; moreover he was required to verify these truths for him- 
self over and over again, and to prove his thorough acquaintance 
with them by a series of practical examinations. Under such a 
system the eyes of the student were in constant demand storing 
up mental pictures, and there was no time for taking notes. It 
was therefore necessary for him to have some text-book containing 
accurate and concise statements of the facts of Anatomy which he 
could verify for himself on the cadaver. To meet this need Dr. William Beverley Towles. 
T i 
owies had his “ Notes on Anatomy,” which he had prepared 
Avhile Demonstrator, lithographed, and copies of these were sup- 
plied to the students. These books, however, were so full of cleri- 
Cal mistakes that he determined to have the “ Notes ” printed, and 
111 this form they are now introduced to the profession. Had he 
lived he would have elaborated it into a complete text-book worthy 
°1 his knowledge and reputation as an anatomist. As it is, the 
can give no adequate conception of his ability as a teacher; 
1 1§ hut a “ faint adumbration ” of the lectures delivered by him. 
1 still contains some errors, old inaccuracies of statement, of 
hich he by no means approved, but which have been handed 
hown to us from the ancients and are still retained by the author!- 
hes. Nevertheless the book as it now stands excels all others 
hiiown to the writer in the accuracy, clearness, and conciseness 
which the truths of Anatomy are stated, and will be of the 
Aeatest assistance to the student. 
To Dr. W. Gl. Christian is due the credit of correcting the 
errors, and the sections on Hernia, the Axilla, and the 
emale Generative organs have been supplied by him from notes 
liieh he took on the lectures delivered by Dr. Towles. 
RICHARD H. WHITEHEAD. 
University of North Carolina, 
November 15 th, 1893. NOTES ON ANATOMY. 
BY 
WM. B. TOWLES, M. D., 
Professor of Anatomy and Materia Medica in the University of 
Virginia, 
AND 
Professor of Anatomy in the University of Vermont. 
ANDERSON BROS.. PUBLISHERS, 
University of Virginia. 
1893. Copyrighted, 1893, 
By WM. B. TOWLES. NOTES ON ANATOMY. 
OSTEOLOGY. 
'l'he study of the bones which go to form the human skeleton, individu- 
all.V and in relation to one another, with regard to the appearances which 
they present to the unaided eye, and the uses for which they are intended, 
institutes Osteology, as pertaining to Descriptive Anatomy. The chief 
Uses °f bones in the living body are: ist. To give support to the softer 
tlssues. 2d. To form receptacles for important organs. 3d. To form 
Unyielding points of attachment for the muscles. 4th. To serve as levers, 
r°ugh which muscular action may be utilized. 
In order to fulfill these functions, bones present many different points 
r study. They may be divided in a general way into: ist. Long Bones, 
w^en the extension in one direction greatly exceeds that in the others. 
' at B°nes> when the extension in two directions greatly exceeds 
1 m the other. 3d. Irregular Bones, when the preceding distinctions 
n°t exist. In the study of a bone, notice: ist. Its position and rela- 
nto other bones. 2d. The class to which it belongs. 3d. Give a 
k ScnPtion of the appearances on the bone: whether there be surfaces, 
orders, extremities, shaft, depressions or elevations, and especially note 
any articular surfaces, that is a surface produced by contact with another 
fr°ne' this connection it is proper to explain certain technicalities of 
ec[uent use—lnternal and External—these terms should be used with 
refer 
ence to the middle line or plane of the body, that is one object is 
Vernal to another because it is nearer the middle line. They are often 
incorrectly with reference to a cavity; interior and exterior are the 
er^S he here employed. 
he bones are divided into those of the vertebral column; of the 
, °rax’ °f the Upper Extremity ; of the Lower Extremity; of the skull; 
e Os Hyoides; the Ossicula Auditus. 
The Vertebral Column. 
Th 
cla 6 Verte^ral column, or spine, consists of a series of separate bones, 
Ssed as irregular, called vertebrae, and extends from the base of the 4 
Notes on Anatomy. 
skull to the lower termination of the pelvis. It is flexuous in direction 
and of unequal size at different places, smallest in the neck, it gradually 
enlarges to below its middle and then suddenly tapers to a point. It 
transmits the weight of the head to the lower extremities, giving support 
on each side to the bones which enclose the thoracic cavity, and indi- 
rectly to those of the upper extremities, towards its lower termination it 
has expanding from it on either side the bones which form the pelvis. 
It forms the receptacle for the spinal marrow and its envelopes. In the 
adult it consists of twenty-six pieces, called vertebrae, which are divided 
into four classes; in the neck they are called cervical vertebrae, and are 
seven in number: 
In the Thoracic region—Dorsal—twelve in number. 
In the Abdominal region—Lumbar—five in number. 
In the Pelvic region—Pelvic—two in number. 
The last are known as sacrum and coccyx, and before adult life are 
composed of nine pieces—the sacrum having five and the coccyx four. 
The vertebrae of the different regions have characteristics which distin- 
guish them from those of other regions, and each vertebra certain less 
noticeable ones which designate its position in its own region. Each 
region, however, possesses one or more bones so widely different from 
the typical vertebra of that region as to deserve the appellation of 
“ Peculiar,” 
Since there are appearances common to the vertebrae of all regions, 
these must be first noted. 
Vertebra. 
Each vertebra consists of the following parts: ist, Body; 2d, Foramen 
for the spinal cord; 3d, Laminae (2); 4th, Pedicles (2); sth, Spinous Process; 
6th, Transverse Processes (2); 7th, Articular Processes (4); Bth, Inter- 
vertebral Notches (4). 
ist. The Body is the front, thick, massive portion of the bone, flattened 
above and below to articulate with adjoining bones, indirectly, by the 
intervention of cartilage; it is more or less circular in outline and slightly 
flattened behind; the edges project somewhat in front and laterally, so as 
to produce a furrow on the front; its posterior aspect forms the anterior 
boundary of the spinal foramen. 
2d. The Spinal Foramen lies between the body in front and the spinous 
process behind, and is bounded laterally by the laminae. It is a large 
opening, varying in form and size in the different regions. 
3d. The Lamina springs, one each side, from the postero-lateral 
aspect of the body, through the medium of the pedicle, and arches back 
to meet its fellow to form the spinous process, thus enclosing the spinal Osteology. 
5 
foramen. It is flattened from side to side, and presents an upper and a 
fower border. 
4th. The Pedicle is the more or less rounded commencement of the 
lamina. 
sth. The Spinous Process juts backward from the union of the two 
laminae. 
6th. The Transverse Process projects laterally from near the anterior 
extremity of the lamina on either side. 
7th. The Articular Processes are four, two superior and two inferior. 
Th . 
ney extend upward and downward from the lamina. 
Bth. The Intervertebral Notches are four, two superior and two in- 
ferior; they are furrows on the upper and lower aspects of the pedicles. 
Cervical Vertebra. 
The discrimination of a Cervical Vertebra involves the following 
60lnts: it is the smallest; its body is smallest, having its transverse diam- 
eter greater than the antero-posterior; on its upper aspect the lateral 
e6ges are raised into ridges. The spinal foramen is largest and is tri- 
angular. The lamina is narrow and long. The spinous process is tri- 
angular and bifid at the extremity, generally. The transverse process is 
Perforated at its base by an opening called the vertebral foramen, is 
grooved above and bifid at its extremity, forming two nodules which are 
Called the anterior and posterior tubercles of the transverse processes. 
fe Articular processes are oblique; the superior face upward, outward 
and backward, the inferior downward, forward and inward. 
SUMMARY. 
Tody small—Transverse diameter greatest—Ridged laterally, above. 
oramen large and triangular. Lamina slender, long, horizontal. Spi- 
n°Us process, triangular, bifid, horizontal. Transverse process, perfo- 
rated, furrowed, forked. Articular process, oblique—Superior face up- 
Ward, outward and backward; inferior, downward, forward and inward. 
Dorsal Vertebra 
To discriminate a typical Dorsal Vertebra the following appearances 
rtlUst be noted: 
The body is intermediate in size between that of a cervical and lumbar 
Vertebra; there is no great preponderance of the one diameter over the 
°fber; although in the upper part of the region the transverse is slightly 
Sreater, and in the middle portion the antero-posterior. The most char- 
acteristic feature is the appearance, on the postero lateral aspect, of the Notes on Anatomy. 
body articular half-facets, situated, two on each side, at the upper and lower 
borders; these are for the reception of the heads of the ribs. The spi- 
nal foramen is smaller than in the other regions, and is nearly round. 
The lamina is short, slopes obliquely from behind, upward and forward, 
and is almost entirely covered by the origin of the processes which spring 
from it. The pedicle is deeply notched inferiorly. The spinous process 
is triangular, and is distinguished from that of a cervical vertebra by not 
being bifid, it extends downward and slightly backward. The trans- 
verse process is peculiarly well marked, being large, long and extending 
outward and backward, increasing in size as it removes from its origin so 
as to present an enlargement at its termination; that is, it is “ clubbed.” 
It bears on its anterior face, near its termination, an articular facet. The 
superior articular processes are vertical and look from each other, outward 
and backward ; the inferior are opposite. 
SUMMARY. 
Body, no preponderating diameter; size, medium; Postero laterally has 
demi facets; Foramen, small and rounded. Lamina, short, oblique and 
covered by processes. Pedicle, deeply notched inferiorly. Spinous 
Process, triangular and not bifid. Transverse Process, large, clubbed— 
articular facet near end. Articular Process vertical—superior averted ; 
inferior look towards each other. 
Lumbar Vertebra. 
The following is a description of a typical lumbar vertebra: The bone 
is altogether larger than those of other regions' 
The body is larger, and is distinguished by two negative features; it 
lacks the lateral ridges on its upper surface, and the articular demi-facets 
on its postero-lateral aspect; the former discriminating it from a cervi- 
cal and the latter from a dorsal vertebra. The spinal foramen is indis- 
tinctly triangular, and is intermediate in size, between the large cervical 
and the small dorsal foramen. The lamina is comparatively small, is 
horizontal, and presents no marked features. The spinous process is 
quite characteristic; its sides are quadrilateral in outline. The transverse 
process is long, and tends to a point, defined by the word “rib-like.” 
The superior articular processes are vertical, and look towards each oth- 
er, being farther apart than the inferior, owing to the fact that the inferior 
articular processes of one vertebra are received between the superior pro- 
cesses of the succeeding vertebra. The inferior articular processes are 
averted. Osteology. 
Body—large; no articular facet and no ridges above. 
Boramen—obscurely triangular and of medium size. 
Lamina—horizontal; Spinous process, quadrilateral. 
Transverse process—pointed, rib-like, 
Articular processes—Vertical—Superior face each other; inferior 
averted. 
SUMMARY. 
Peculiar Vertebrae. 
The foregoing description of a vertebra in each region is, as stated, of 
otle typical of that region; and this typical vertebra is one from about 
centre of that region. Toward the confines of each region the ver- 
tebrae partake more or less of the characters of vertebrae in the adjoining 
egions, and so far depart from the type as to deserve the appellation 
Peculiar ”—thus demanding a special description. The departure 
Lorn the typical vertebra is so great in some instances that the bones 
have received special names. 
In the cervical region there are three peculiar vertebrae—the first, 
Second and seventh. 
The First Cervical Vertebra, or Atlas. 
This vertebra is known as the Atlas because it supports the weight of 
head; it resembles only in a slight degree a typical vertebra, having 
n° body and being scarcely more than a ring of bone. It is described 
as consisting of four parts—two arches and two lateral masses—sur- 
r°unding a spinal foramen of remarkable size—much larger than in any 
°ther vertebra. 
The lateral masses stand one on each side, being connected before and 
behind by the anterior and posterior arch. The anterior arch is much 
shorter than the posterior, and forms one-fifth of the circumference of 
the bone ; it presents on the centre of its front an elevation, called the 
anterior tubercle of the Atlas, and just behind this, on the posterior face 
°I the anterior arch, is an articular facet for the odontoid process of the 
next vertebra. The posterior arch forms about two fifths of the circum- 
ference of the bone, and presents nothing worthy of note,except the pos- 
terior tubercle of the Atlas, found at the centre of the posterior face, 
Representing the rudiment of a spinous process, and on each side just 
efiind the lateral mass is, perhaps, a slight groove. Each lateral mass 
°rms about one-fifth of the bone’s circle, and sustains above and below 
the articular processes ; the superior are characteristic of the upper 
asPect of the bone; each is an oval, oblique, articular pit, approaching 8 
Notes on Anatomy. 
its fellow of the opposite side anteriorly. The direction of its obliquity 
is upward, forward, and inward; just behind this is seen the superior 
intervertebral notch, thus differing from other vertebrae, in which it is in 
front. The inferior articular processes are smaller, flat and round. The 
transverse process is flat and presents the perforation, but not the furrow 
above nor the forked end of other cervical vertebrae, on the inner face is 
a roughness. 
Anterior Arch—one-fifth of bone; has on its front centre, anterior 
tubercle; on rear centre, articular facet for odontoid process. 
Posterior Arch—two-fifths of bone—Posterior tubercle—Superior inter- 
vertebral notch. 
Lateral Mass—one-fifth of bone—Articular processes, superior Con- 
cave, oval, oblique, articular; intervertebral notch behind it, inferior, flat 
and circular. Inner face rough. 
SUMMARY. 
This vertebra presents as its most distinguishing feature, a remarkable 
process called odontoid,(tooth-like), which springs upward from the supe- 
rior aspect of the body and seems as though it were the body of the 
Atlas, separated from it and attached to the Axis. The process is con- 
stricted at its origin, the neck ; it next enlarges and finally tapers to a 
point, it presents in front just below its summit, an articular facet for the 
anterior arch of the Atlas, and opposite to this, on its posterior aspect, a 
smooth surface for the play of a ligament—the transverse; just below its 
top on each side is a prominent rough surface for the attachment of a 
ligament—the check. 
Axis, or Second Cervical Vertebra. 
The Body presents on its centre in front a vertical ridge and on either 
side of this a furrow; the upper surface is almost entirely occupied by the 
origin of the odontoid process, the inferior surface is oblique downward 
and forward. The spinal foramen is large; the laminae bulky ; the trans- 
verse processes small, perforated and almost hidden by the articular pro- 
cesses. The spinous process is large. The superior articular process is 
flat and circular. 
SUMMARY. 
Body—ridge in front, furrow on each side ; inferior surface sloping 
downward and forward. 
Foramen—large. Lamina—strong. 
Spinous Process—massive. 
Transverse Process—small and perforated. 
Superior Articular—flat and circular. Osteology. 
9 
Odontoid Process—constricted, then enlarged, then pointed; anterior 
and posterior articular facets and lateral roughness for ligaments. 
Vertebra Prominens, or Seventh Cervical Vertebra. 
The seventh cervical vertebra derives its sobriquet of prominens from 
possession of a remarkably long spinous process, which distinguishes 
from other cervical vertebrae. 
Peculiar Dorsal Vertebrae. 
The peculiar dorsal vertebrae are the first, ninth, tenth, eleventh and 
twelfth. 
The first presents on each side of its body, above and postero-late- 
rally> a whole facet for the head of a rib; below, in corresponding posi- 
tlon> a half facet on each side. The ninth has but one demi-facet on 
each side, which is on the upper border. The tenth has one whole facet 
°n each side. The eleventh has one whole facet on each side, but its 
transverse process has no articular facet. The tzvelfith has one whole 
frcet on each side; its transverse process has no articular facet and its 
lnferior articular processes are averted. 
The Pelvic Vertebrae. 
The pelvic vertebrae, specifically known as sacrum and coccyx, form 
lower part of the vertebral column, and derive the appellation of pel- 
Vlc from the fact that they form the posterior wall of the pelvis in the 
articulated skeleton. They are described separately. 
Sacrum. 
The sacrum lies between the fifth lumbar vertebra above and the coc- 
cyx below, and between the two ossa innominata. It is triangular in 
°utline, its base being upward and its truncated apex below and back- 
Ward and tipped by the coccyx. Its anterior face is concave, more so in 
nien than in women, this being one means of distinguishing the sex to 
which the pelvis belonged. It is described as consisting of an anterior 
and posterior face, two lateral borders, a base and an apex. 
The anterior face is concave and presents two vertical rows of foramina, 
four each, one row on each side of the middle line, called the an- 
terior sacral foramina; the upper two in each row, are considerably 
arger than the lower two. Connecting each foramen with the corres- 
ponding one in the opposite row is a ridge; these ridges marking the 
lne of union of the five separate vertebrae of which the sacrum consisted 10 
Notes on Anatomy. 
in the young subject. Passing outward from each foramen is a groove 
for a sacral nerve. 
The posterior face is convex and narrower than the anterior. It is 
marked down its centre by a series of rough projections, constituting the 
sacral spine ; these projections are the rudiments of spinous processes 
and grow smaller and at the lower part disappear, thus leaving exposed 
the lower opening of the sacral canal. External to the sacral spine,towards 
the lateral border on each side, is a row of foramina (of four each), called 
the posterior sacral foramina; these are smaller than the anterior; between 
each row of foramina and the sacral spine is observed a row of five 
tubercles, the rudiments of articular processes; external to each row of 
foramina is seen another row of tubercles, the rudiments of transverse 
processes. 
The lateral border presents at its upper part a broad, rough, ear-shaped, 
or auricular surface, and behind this an exceedingly rough cavity ; below, 
the border becomes thin and a rough edge. 
The base, or superior border, presents in the centre a large oval sur- 
face, corresponding to the lower surface of the body of the fifth lumbar 
vertebra, with which it articulates. Extending outward on each side of 
this oval surface, is the portion of the base called the wing of the sacrum. 
Just behind the oval surface is the opening of the sacral canal, which 
is the continuation of the spinal canal from above downward through the 
sacrum. On each side of this opening is an articular process, in front 
of which, and to the side of the oval surface, is a groove called the inter 
vertebral notch. 
The apex, or inferior extremity of the sacrum, presents an oval surface 
for articulation with the coccyx, and on each side of this a projection— 
articular process—called the cornu. Behind the oval surface is the open- 
ing of the sacral canal which terminates the spinal canal. 
SUMMARY. 
Anterior Face—concave—Four pairs foramina, connecting each pair a 
ridge, external to each foramen a groove. 
Posterior Face—convex—sacral spine—five articular processes, four 
posterior sacral foramina, five transverse processes. 
Lateral Border—auricular surface—rough cavity—rough edge. 
Base—Oval articular surface—wings—intervertebral notches —sacral 
canal—articular processes. 
Apex—Articular surface—cornu. Osteology. 
11 
Coccyx. 
The coccyx forms the lower extremity of the vertebral column; it 
originally consists of four pieces or vertebrae united, in the adult, into 
°ne bone, which is sometimes ossified to the sacrum. It is triangular in 
shape ; its base is above, presenting an oval articular facet for the trun- 
dled apex of the sacrum; its apex is below and forward, the bone con- 
tinuing the curve of the sacrum and frequently deviating to one side. 
Vertebral Column as a Whole. 
Upon casual observation the spinal column seems to increase in size 
from the second cervical vertebra to the sacrum, and then diminish sud- 
denly }ts termination; but upon close observation it is found, indeed, 
to increase in size from the first cervical to the first dorsal, but then it 
diminishes to the fourth dorsal, then increases again to the sacrum and 
again diminishes to its termination. The length of the column in the 
adult is from twenty-four to twenty-eight inches. It presents the follow- 
lng antero -posterior curvatures; In the neck it is convex forward, the 
drst and second dorsal vertebrae partaking of this convexity ; in the 
thoracic region it is concave forward ; in the lumbar region it is again 
convex forward; in the pelvic region it is once more concave forward. 
viewed from behind we see the projecting spinous processes, 
"'hich in the cervical region are nearly horizontal, in the dorsal nearly 
Vertically downward, and in the lumbar horizontal. 
Sternum. 
The sternum, or breast bone, forms the front centre of the thoracic 
Wah, as the dorsal vertebrae form the rear centre; connecting these on 
each side are the ribs, which are prolonged by the costal cartilages. Ex- 
tending outward from the upper end of the sternum on each side is the 
clavicle. So that the Thorax, or Chest, may be then bounded—in front 
y the sternum and seven costal cartilages ; behind by the dorsal vertebrae, 
Orally by the ribs. The direction of the long axis of the sternum is 
downward and forward. Originally consisting of six parts, these in the 
adult become united into three—the upper or Manubrium, the middle, 
°r Gladiolus, and the lower, or Ensiform, or Xiphoid cartilage. These 
are United by cartilage, but later in life may become ossified together, 
lbe ensiform cartilage frequently becoming ossified and firmly united 
t0 the gladiolus. 
The Manubrium, or upper bone of the sternum, is the broadest part 
and is widest above. In its centre above is’ seen a depression called the 12 
Notes on Anatomy. 
interclavicular notch; on each side of this is an articular surface for the 
clavicle, of concavo-convex shape; on each lateral border are seen one 
whole pit, for the reception of the cartilage of the first rib, and half the 
pit for the second, which falls at the junction of the Manubrium and 
Gladiolus. 
The Gladiolus, or middle piece of the sternum, is the longest, is broad- 
est in the centre and presents on each lateral border pits for the costal 
cartilages as follows, from above downward ; a half pit for the second, 
four whole pits and a half pit for the seventh. 
The Ensiform cartilage is the lowest piece of the sternum and presents 
many variations, sometimes bifid, or perforated, pointed or broad, or 
inclined laterally, forward, or backward. Laterally it carries above a 
half pit for the seventh rib. Considered as a whole, the sternum is convex 
anteriorly, and presents the transverse ridges, which become progress- 
ively indistinct below, marking the lines of union of its original constitu- 
ents. When the Manubrium and Gladiolus are ossified together their 
union is marked by a very noticeable ridge, otherwise this place is marked, 
in the prepared bone, by a depression due to shrinkage of the uniting 
cartilage. The posterior surface is concave. The upper end is thick and 
broad and bears the interclavicular notch, with the articular surface for 
the clavicle on each side. Each side presents seven notches for the 
costal cartilages—the second falling at the junction of the Manubrium 
and Gladiolus, and the seventh at the junction of the Gladiolus and Ensi- 
form cartilage. 
SUMMARY. 
Anterior Surface—convex, marked by ridges. 
Posterior Surface—concave. 
Lateral Border—seven pits for costal cartilages. 
Upper End—interclavicular notch; two articular surfaces for clavicles. 
Subdivisions—three: 
(a) Manubrium, or upper piece ; upper end broad ; interclavicular 
notch ; two articular surfaces for clavicles; one whole and one half pit for 
cartilages. 
(b) Gladiolus, or middle piece; broadest in centre; sides present four 
whole and two half pits. 
(c) Ensiform, or Xiphoid Cartilage—variable, either bifid, pointed or 
perforated, &c.; laterally a half pit. 
The Ribs. 
The ribs are twelve in number on each side, and are numbered from 
above downward, being usually divided into true and false. The true Osteology. 
13 
ribs are the upper seven, and the false the lower five. The last two are 
called floating-, since the cartilages, which merely tip them, are free. A 
better sub-division is into: ist, the upper seven, vertebro-sternal; 2d, 
the next three, vertebro-costal ; 3d, the last two, “ vertebral.” 
The ribs curve around the sides of the thorax from the dorsal verte- 
brae, forming the sides and part of the back of that cavity ; the vertebro- 
sternal stop short of the sternum, and are connected to it by means of 
cartilages; the vertebro-costal are connected, each by means of its carti- 
aSe> with the cartilage of the preceding rib; and the last two, as before 
stated, are merely tipped by cartilage, and are free. 
The ribs increase in length from the first to the seventh and then de- 
crease to the last; they decrease in width from the first to the last; they 
are broader anteriorly than posteriorly, except in the case of the last two. 
In describing the ribs the appearances more or less common to them 
aH will first be given, under the heading “ A Rib,” then the exceptions 
to this description will be noted. 
A Rib. 
A rib consists of two extremities, two surfaces and two borders. 
The external surface is convex ; the internal concave from before back- 
wards; the upper border is thick and rounded ; the lower, thin and sharp 
and marked by a groove on its inner surface. The posterior extremity 
terminates in a rounded articular surface called a head; this surface consists 
°t two parts, separated by a horizontal ridge; the existence of this ridge 
being due to the fact that the rib articulates with two vertebrae, and the 
ridge 
is received between the two bodies. That portion of the rib support- 
lng the head is called the neck, it presents a rough surface posteriorly and a 
ridge called the crest, on its upper aspect. The neck terminates anteri- 
-orly in a prominence called the tubercle, which is situated on the outer 
0r posterior aspect of the rib, is generally rough, but presents at its base 
and inferiorly an articular surface corresponding to a similar one on the 
transverse process of a dorsal vertebra. The anterior extremity of a rib 
ls thinner and broader than the posterior, and bears on its end a shallow 
Pit for its cartilage. 
Laying a rib, with its lower border downward, on a plane surface, it is 
°bserved to be twnsted. On its outer surface near its tubercle is seen an 
°blique ridge, where its angle is located, and from this point backward 
the rib rises: this fact accounts for the ribs being oblique instead of hori- 
z°ntal when articulated. 14 
Notes on Anatomy. 
SUMMARY. 
The ribs are twelve on each side, numbered from above downward and 
classified thus; upper seven, vertebro-sternal; next three, vertebro-cos- 
tal; last two, Vertebral. 
External surface convex. 
Internal surface concave. 
Superior Border thick and rounded. 
Inferior Border thin, sharp, grooved internally. 
Posterior Extremity, Head—two articular surfaces separated by a hori- 
zontal ridge. 
Neck—extends from head to tubercle; crest above and rough behind. 
Tubercle—rough; articular facet beneath. 
Angle and twist. 
The variation from the foregoing description will be found in the fol 
lowing ribs: 
The first rib is by far the most important; it is the broadest and short- 
est, is less oblique, has no angle or twist, presents one articular surface 
on the head—because it articulates with but one vertebra—and has its 
two surfaces looking upward and downward, and its two borders, exter- 
nal and internal. On its upper surface are two grooves, separated by a 
tubercle near the inner border with a ridge running from it forward and 
outward; the anterior groove is for the subclavian vein, and the posterior, 
which is deeper, is for the subclavian artery. 
The second rib has on its outer surface near the middle a broad 
ridge. 
The tenth, eleventh and twelfth ribs articulate with but one vertebra 
each, and have no ridge on the head. 
The eleventh and twelfth have no tubercles and no groove on the 
lower border. 
Costal Cartilages. 
The costal cartilages correspond in number to the ribs, which they 
prolong anteriorly. They increase in length from the first to the 
seventh, then decrease to the last. In width they decrease from the first 
to the last. The first seven extend between the vertebro-sternal ribs and 
the side of the sternum; the next three connect the ends of the vertebro- 
costal ribs with one another, the last two are free. The first several are 
horizontal and those ensuing incline more and more upward, except the 
two last, which are horizontal. Osteology. 
15 
The skeleton of the upper extremity is divided into four segments, 
shoulder, arm, forearm, hand. 
The skeleton of the shoulder consists of the clavicle and scapula. 
The skeleton of the arm consists of the humerus. 
The skeleton of the forearm consists of the radius and ulna. 
The skeleton of the hand consists of the bones of the carpus, metacar- 
PUs and phalanges. 
The Skeleton of the Upper Extremity. 
The Skeleton of the Shoulder— 
The Clavicle. 
The Clavicle, or collar bone, extends nearly horizontally outward from 
lhe upper end of the sternum, on each side, to the scapula. It maybe 
divided into two extremities, two surfaces and two borders. 
The inner extremity is the thicker, in fact the bone for some distance 
gradually enlarges towards the inner extremity. It is rounded, or tri- 
angular, bears on its extremity a concavo-convex articular surface for 
arbculation with the manubrium, and generally another articular facet 
lnferiorly to play on the first costal cartilage. The outer extremity is 
fattened from above downward, and presents at its tip a small articular 
k°et for articulation, with the acromion process of the scapula. 
The superior surface is rounded, convex and presents a roughness near 
the inner end. 
The inferior surface presents a long shallow groove, terminated inter- 
flally ancj externally by a process, the inner one called the rhomboid, the 
outer the conoid; extending outward and forward from this is a rough 
ri%e,the trapezoid. The anterior border is convex for its inner, two-thirds, 
then concave; the posterior border is concave for its inner four-fifths, then 
Convex. The clavicle is larger and more curved in a subject who has led a 
laborious life. 
Inner Extremity—thick, rounded or triangular; two articular surfaces. 
Outer Extremity—thin, flat, articular facet for acromion. 
Superior Surface—rounded, convex; Tubercle internally. 
Inferior Surface—grooved, conoid and rhomboid tubercles. 
Anterior Border—convex for inner two-thirds ; concave for outer one- 
third. 
Posterior Border—concave for inner four-fifths; convex for outer one- 
nfth. 
SUMMARY. 16 
Notes on Anatomy. 
The Scapula. 
The scapula or shoulder blade, is a flat, triangular bone, situated on the 
upper postero-lateral aspect of the chest, over the upper eight ribs, ex- 
cept the first. It consists of a body, having two surfaces, three angles, 
three borders, and of two processes. The anterior face, or venter, or 
sub-scapular fossa, is concave, has ridges running upward and outward, 
and presents a deeper depression towards its upper outer part called the 
subscapular angle. 
The posterior face, or dorsum, is somewhat convex, presenting a promi- 
nent ridge, the spine, passing from the posterior border towards the 
head and dividing the dorsum into two unequal parts; the smaller, above 
the spine, called the supraspinous fossa; the three fold larger below, 
called the infraspinous fossa. The spine is triangular and presents three 
borders, two of which are free, one looking backward and the other for- 
ward and forming a smooth rounded edge which is continued into the 
acromion : around this the supra and infraspinous fossae communicate. 
The third border is the attached one. The spine begins at the posterior 
border of the scapula, by a triangular smooth surface, and gradually 
rises to terminate in the acromion process. 
The infraspinous fossa presents just beneath the spine a bulge, exter- 
nal to which is a deep, broad vertical groove ; external to this a promi- 
nent vertical ridge ; and external to this a smooth surface, widening as it 
descends towards the inferior angle, and, crossing this surface, an oblique 
ridge. The supraspinous fossa is concave, and about one-third the size 
of the infraspinous. 
The superior border is thin and the shortest and deeply notched to- 
wards its outer end, this notch being called suprascapular. The ante- 
rior axillary, or inferior border, is thick and presents several grooves and, 
for about an inch above, a ridge. The posterior border, or base of the 
scapula, is the longest, and presents at the intersection of the spine a pro- 
jection, the border retreating from this point both above and below. 
The superior angle, situated at the junction of the superior and poste- 
rior borders, is about a right angle. The inferior angle, at the junction 
of the posterior and axillary borders, is acute and thick. The anterior 
angle is expanded and fashioned into a head, bearing on its extremity 
the glenoid cavity, which is a shallow, concave articular surface, oval in 
outline, smaller above than below, and having its long diameter vertical. 
Just behind, and supporting the glenoid cavity, is a constricted portion 
of the bone called the neck of the scapula. The processes of the scapula 
are two: acromion and coracoid. The coracoid springs from the bone Osteology. 
17 
lust above the glenoid cavity and projects upwards, and then turns and 
rUns outwards and forwards. 
The acromion is the outer termination of the spine, being flattened from 
above and behind downward and forward, it overhangs the glenoid cavity; 
Js convex above, concave below, and presents on its inner border about 
lts middle an articular facet for the outer end of the clavicle. 
Posterior Face—convex—supraspinous fossa—spine, which is trian- 
£ular and presents three borders, two free—begins at post-border by 
Srn°°th surface and gradually rises to terminate in the acromion. Infra- 
sPmous fossa—bulge, vertical groove and ridge, smooth surface, oblique 
Pdge. 
SUMMARY. 
Anterior Face—venter, concave, sub scapular fossa, oblique ridges- 
Sub-scapular angle. 
Upper Border—shortest—thin—terminates in front in notch. 
Anterior Border—axillary or lower, thick grooved, ridged. 
Posterior Border—base—longest; angle at intersection of spine. 
Superior Angle—a right angle. 
Inferior Angle-acute, thick. 
Anterior Angle—head, glenoid cavity, articular, shallow, concave, oval, 
°nS diameter vertical, large end below, Neck. 
Acromion Process—convex above—concave below, oval, articular facet 
0n inner border. 
Coracoid—Overhangs glenoid cavity—projects forwards and inwards. 
The Skeleton of the Arm— 
Humerus. 
The humerus forms the skeleton of the arm, extending from the 
°ulder to the elbow. Like other long bones, it may be divided into a 
s aft and two extremities. 
The upper extremity presents the following appearances: Surmounting 
18 extremity is the head, which is smooth, articular, forms some- 
less than half a sphere, and articulates with the glenoid cavity of 
e scapula. Just beneath the head the bone is observed to be con- 
victed; this is known as the anatomical neck. Beneath this, externally 
and anteriorly, are two eminences, separated by a groove; the outer, and 
aVch the larger, is called the greater; the inner the lesser tuberosity ; 
e groove is called bicipital, and its edges are known as the anterior and 
Posterior bicipital ridges respectively. That portion of the bone imme- 
tely below the tuberosities is known as the surgical neck. 
2 18 
Notes on Anatomy, 
The lower extremity of the humerus presents the two condyles, one on 
either side, the inner being; the more prominent. Passing up from each 
is a ridge called condyloid, the external being more prominent. The 
extremity bears an irregular articular surface, which is formed of the 
following parts from without inward : a rounded articular projection 
known as the eminentia capitata, whose articular surface encroaches 
more on the front than the rear and is intended for articulation with the 
radius ; just internal to this is a non-articular antero-posterior groove ; 
internal to this a pulley-like articular surface—consisting of two antero- 
posterior ridges, with an intervening groove, which is known as the pul- 
ley, or trochlea of the humerus and articulates with the ulna. Just above 
the trochlea in front is a depression called the coronoid fossa and just 
above it behind is another deeper depression called the olecranoid fossa. 
The shaft of the humerus is three sided, or prismoid, presenting three 
surfaces and three borders. 
The anterior border begins at the front of the greater tuberosity and 
terminates at the coronoid fossa. The external border begins at the back 
of the greater tuberosity and terminates in the external condyloid ridge. 
The internal border begins at the lesser tuberosity and terminates at the 
internal condyloid ridge. 
The external face presents about the middle the union, at an acute an- 
gle, of two rough ridges approaching each other from above; this is 
known as the deltoid V. Below this the external face becomes anterior 
and concave. The internal face shows, above, the bicipital groove. The 
posterior face is smooth, convex and obliquely grooved about its centre 
from within downward and outward, the groove being called the mus- 
culo-spiral. 
Upper extremity—Hemispherical head ; anatomical neck. Greater 
and lesser tuberosities. Bicipital groove and ridges. Surgical neck. 
SUMMARY 
Lower Extremity—External and internal condyles. From without in- 
ward, enimentia capitata, groove, trochlea ; coronoid fossa in front, ole- 
cranoid behind. 
Shaft—External Face: Deltoid “V”; below, anterior and concave. 
Internal Face • Bicipital groove. 
Posterior Face; Smooth, musculo-spiral groove. 
The Skeleton of the Forearm. 
The skeleton of the forearm consists of two bones lying side by side, 
the inner known as the ulna, the outer as radius. Osteology. 
19 
The ulna is the inner bone of the forearm, and is divided, like all long 
°nes> into a shaft and two extremities. 
The Ulna. 
The upper extremity is much the larger and may be described as con- 
Slsting of two parts or processes, one of which, the olecranon, terminates 
*he extremity, the other, the coronoid, projecting from the base of the 
°lecranon forward. Sweeping between these and appropriating the front 
°/ olecranon and the upper part of the coronoid, is an extensive ar- 
tlcular surface, corresponding to the trochlea of the humerus, and called 
the greater sigmoid cavity, which presents a deep concavity in profile 
and a vertical ridge along its entire centre. Just where we might suppose 
two processes to meet is a notch on each side. Posteriorly, the ole- 
Cran°n is rough and triangular; superiorly, it presents a quadrilateral 
r°ugh surface; anteriorly it is concave and forms part of the great sig- 
rn°1d cavity, and its central, vertical ridge; it terminates antero-superi- 
°rly in 
a small but marked projection, overhanging the sigmoid cavity, 
CaUed its beak; extending outward and downward, diverging on each 
Slbe from immediately behind the beak, and continuing to a point just 
P°sterior to the edge of the greater sigmoid cavity, is a groove. 
the coronoid process juts forward from the base of the olecranon. 
°ve it forms a part of the great sigmoid cavity and its central ridge ; 
0w it shows a rough concave surface for the attachment of a muscle— 
e hrachialis anticus; on its outer side is seen an articular concavity, 
Cahed the lesser sigmoid cavity, in which the rim of the head of the 
raclius plays, below which is a depressed, rough triangular surface. 
the lower extremity of the ulna is much smaller than the upper, and 
c°nsists of two projections separated by a notch; the inner is the smaller 
longer and comes to an apex; it is called the styloid process of the 
ji a> The outer process is called the capitulum ulnae, and is articular- 
e°n its summit; circumscribing the rim of the outer half of this is an 
arhcular surface against which the lower end of the radius plays. 
he shaft of the ulna is three-sided, hence presenting three borders 
three surfaces. The anterior border begins above at the inner side 
the coronoid process, and terminates at the front of the styloid pro- 
s- The posterior border begins at the apex of the triangular posterior 
Urfece of the olecrannon and terminates at the back of the styloid pro- 
cess 'T'l-i t . 
sid * Ane externa* border begins by the convergence of a line from each 
°f the lesser sigmoid cavity, and terminates at the capitulum ulnae. 
*s border is sharp and prominent and is called the interosseous border. 
e anterior face is concave. The internal face is concave above 20 
Notes on Anatomy. 
and convex below. The posterior face shows from above downward a 
triangular surface, an oblique ridge and a vertical ridge. 
SUMMARY. 
Upper Extremity—Olecranon and coronoid processes, greater and les- 
ser sigmoid cavities. 
Olecranon—Anterior Face—Articular vertical ridge. 
Posterior Face—Triangular. 
Superior Face—Quadrilateral; beak and groove. 
Coronoid—Superior Face—Articular, ridged. 
Inferior Face—Concave; muscular impression. 
External Edge—Lesser sigmoid cavity. 
Greater Sigmoid Cavity—Ridge in centre, notch on each side. 
Lower Extremity—Styloid process on inner side, external to it a notch; 
external to this,capitulum ulnae, articular-like on summit and articular on 
outer side. 
Shaft—Anterior, posterior and internal surfaces. 
Anterior, posterior and external borders. 
Anterior surface concave. 
Posterior surface from above, triangular depression, oblique and ver- 
tical ridges. 
Internal surface concave above, convex below. 
Radius. 
The radius is the outer of the two bones of the forearm, and is divid- 
ed, like other long bones, into a shaft and two extremities. Unlike the 
ulna, the upper extremity is much smaller than the lower. The upper 
extremity presents a head, upon whose summit is an articular cup- 
shaped depression for articulation with the enimentia capitata of the 
humerus. Surrounding this depression is an articular rim, and support- 
ing these is a constricted portion called the neck, terminating below on 
the inner side, at a projection .called the tubercle,or the bicipital tuberosi- 
ty, which is divided by a ridge into a rough posterior and a smooth ante- 
rior portion. 
Turning to the lower extremity, it is seen to be much larger than the 
upper, presenting upon its summit a triangular articular cavity, carpal, 
having its apex outward, and terminating on the outer side in a pointed 
projection called the styloid process. The carpal cavity is seen to be 
crossed about its centre by a ridge and terminates at the inner edge of 
the bone, upon which is a narrow, non-articular concave portion, above 
which is a concave articular strip called the sigmoid cavity of the radius. Osteology. 
21 
The anterior aspect of the lower extremity is rough and projecting; the 
Posterior has five vertical grooves, two of which are on the styloid pro- 
cess. 
The shaft of the radius presents three surfaces and three borders. The 
anterior border begins at the front of the bicipital tuberosity and passing 
downward and outward forms what is called the oblique ridge, and ter- 
at the styloid process. The posterior border, beginning at the 
Posterior part of the tuberosity, terminates behind the styloid process. 
The internal border or interosseous ridge begins above, also at the tube- 
r°sity and passes downward, sharp and prominent, to terminate by 
hiding into two lines which enclose the sigmoid cavity. 
The anterior face is concave above and becomes wider and flat below. 
Th 
ne posterior face is concave in the centre, but convex above and below. 
Th 
ne external face is convex throughout. 
SUMMARY. 
Upper Extremity—small, head, cup, neck, tuberosity. 
Lower Extremity—Large, articular, triangular carpal cavity with a 
ri<%e; styloid process, which, with posterior aspect, is grooved. 
Shaft—Anterior Face—Concave above; becomes flat and wide below. 
Posterior Face—concave in middle. 
External Face—convex throughout. 
Of the three borders the internal, or interosseous ridge is the sharpest 
and most prominent; and the external is oblique above. 
The skeleton of the hand consists of the skeleton of the carpus, the 
rrietacarpus and phalanges. 
The Hand. 
The Carpus. 
skeleton of the carpus, or wrist consists of seven small, irregular 
nes arranged in two rows one above the other; in the upper row are 
th^6 k°nes’ arranged in the following order from without inward : ist, 
® Scaphoid ; 2d, the Semilunar; 3d, the Cuneiform, on the front of 
ch plays a sesamoid bone, called the pisiform. In the lower row, 
the same order, are: ist, the Trapezium, 2d, Trapezoid; 3d, Os 
agnum; 4th, Unciform. The bones of the upper row articulate lat- 
rally with Qne ajjQjjjgj.. tbe bones on the inner and outer side, respec- 
k S °tker) and hence there is no articular surface on that aspect of the 
to fi68' must further be noted that viewed from the back there appears 
e but three bones in the upper row, placed laterally scaphoid, semi- 22 
Notes on Anatomy. 
lunar, cuneiform; but viewed from the front the pisiform is seen 
perched upon the front of the cuneiform, so that the latter bone has no 
articular facet on its inner side. Above, the upper row presents a convex 
articular surface forming the condyle of the wrist joint; so that in this 
direction all the bones of the row are articular. Below, the upper row 
presents a sinuous articular surface, formed by all three bones, for articu- 
lation with the lower row; externally this surface is convex, internally 
concave. The bones of the lower row, like those of the upper, articulate 
laterally with one another, the outer and inner bones, of course, not being 
articular in a corresponding direction. Above, the lower row’ presents a 
sinuous articular surface, corresponding to that of the upper row wnth 
which it articulates, being convex internally and concave externally. Be- 
low, the lower row is articular to receive the bones of the Metacarpus. 
The bones of neither row’ are articular on the front, or palmar aspect, nor 
on the back, or dorsal aspect, the carpus being but one bone deep ; 
there is one exception to this in the fact that the pisiform lies on the 
front of the cuneiform, and consequently the former has an articular 
dorsal aspect, and the latter an articular palmar aspect. 
The carpus, taken as a whole, is markedly arched transversely, the 
convexity of the arch being dorsal; for this reason the separate bones, 
being the elements of the arch, must necessarily be thicker posteriorly. 
The semilunar is an exception. Hence the dorsal can be easily discrimi- 
nated from the palmar aspect. Bearing this fact in mind, and also that 
in the upper row, the general contour for the articular surface is convex 
and of the lower concave, except for the scaphoid, the individual bones 
may be recognized. The scaphoid has no articular facet on the outer 
side but a round tubercle, and its lower surface is convex. It is said to 
be in form boat like,” coming to a point at the tuberosity on the outer 
side. The semilunar is crescentic in outline and has a deep articular 
cavity below; its palmar aspect is larger than the dorsal. The cunei- 
form presents a non-articular lateral aspect internally, an articular facet 
anteriorly for the pisiform, and is wedge-shaped, the base being external. 
The pisiform is known by its small size and by having but one articular 
facet. The trapezium is non-articular on its outer side, and is especially 
distinguished by having on its palmar aspect a deep groove bounded ex- 
ternally by a ridge terminating in a prominent tubercle. The trapezoid 
is the most difficult to discriminate and is best recognized by exclusion. 
The Os Magnum is the largest bone of the carpus, presenting a rounded 
articular head superiorly. The unciform is recognized by the hook-like 
process projecting from the palmar aspect. Osteology. 
23 
The metacarpus is formed by five bones classed as long bones; four of 
tTese, for the four fingers, being nearly parallel, while the fifth—for the 
thumb—recedes from the others as it descends. The metacarpal bones 
arbculate above with the lower row of the carpus; below with the upper 
extremity of the first phalanges. At their upper ends they articulate 
Wally with one another, except the metacarpal bone of the thumb; 
ktfi at the lower end they do not articulate with one another. The meta- 
Carpus, like the carpus, is arched transversely, the convexity being pos- 
terior. One of its constituents may be thus described : 
Metacarpus. 
A Typical Metacarpal Bone. 
Each metacarpal bone being a long bone, presents a shaft and two ex- 
Amities. The upper extremity, generally called the base, is quadri- 
teral. It is articular on its summit and on its sides. 
The lower extremity, called the head, is terminated by an articular 
ead which is oblong antero-posteriorly and is articular higher in front 
than behind. The lower extremity presents a depression on either side, 
anfl behind this a tubercle ; it is flattened posteriorly and grooved ante- 
riorly. 
The shaft is triangular, and is arched longitudinally with the convexity 
ekward. The lateral faces are slightly concave, and are separated an- 
teriorly by a sharp border. The posterior face presents at its upper 
Part a central longitudinal ridge and on either side of this ridge a slight 
Ptession ; just below the centre of the surface the ridge divides into 
'■w°> which, separating, gradually descend each to the tubercle above the 
eral depression on the lower extremity of the bone, that portion of 
e face between them being flattened. 
This description applies in general more or less closely to all the meta- 
CarPal bones, but each possesses appearances characteristic of itself, by 
ybich it may be discriminated. Each bone is known by the name of the 
. §er it supports ; they are also known by number from without 
lnWard. 
Tl 
ne metacarpal bone of the thumb is the shortest, the largest and is 
sornewhat flattened from before backward. It has upon the summit of 
its K 1 
ase a saddle-shaped, concavo-convex, articular surface and has no 
ateral articular facet. 
metacarpal bone of the index finger is the longest, is next in size 
° that of the thumb and presents on its base two articular facets, one on 
e summit and one lateral. 24 
Notes on Anatomy. 
The metacarpal bone of the middle finger is next in size and length, 
and presents three articular facets on its base, one on the summit and two 
lateral, and a styloid process projecting upward on its dorsal aspect. 
The metacarpal bone of the ring finger is next in size and length ; its 
base presenting three facets—one on the summit and two lateral—the 
outer of which is divided by a groove. 
The metacarpal bone of the little finger is smallest and next to the 
shortest; its base presents two articular facets, one on the summit and 
one on the outer side; on the inner side of the base is a rough promi- 
nent tuberosity. 
The phalanges consist of three rows of long bones, extending from the 
heads of the metacarpal bones to the tips of the fingers. The rows are 
numbered from the metacarpal bones, the third row being usually called 
“ ungual.” The thumb has but two phalanges, the characteristic second 
phalanx being replaced by an ungual, or third. 
Phalanges. 
The first phalanx is longer than the second, its shaft is semi-cylindri- 
cal, with its posterior surface convex. Its base presents on its summit 
an articular cavity for the head of a metacarpal bone. The head, or 
lower extremity, presents a pulley or trochlea for articulation with the 
base of the second phalanx. 
The second phalanx presents on its base a receiving articular surface 
for the trochlea on the head of the first phalanx. Its shaft is semi- 
cylindrical and convex posteriorly. Its lower extremity, or head, pre- 
sents a trochlea for articulatiou with the third phalanx. 
The third, or ungual phalanx, presents on its base an articular surface 
to receive the trochlea of the second: it then becomes narrow and again 
wider, flatter and rougher to support the nail and the tissues of the palp 
of the finger. 
The Skeleton of the Lower Extremity. 
The skeleton of the lower extremity consists of the skeleton of the 
hip, thigh, leg and foot. 
Os Innominatum. 
The two ossa innominata, each forming the skeleton of the hip, are ele- 
ments of the articulated pelvis, each articulating behind with the sacrum, in 
front with its fellow, and below with the thigh bone, or femur. Each 
bone in the young subject is seen to consist of three parts: (ist) An up- 
per, posterior large portion called the ilium ; (2d) a front portion called 
the pubes; (3d) the lower division called ischium. These three elements, Osteology. 
25 
known each as a separate bone, meet in the articular cavity for the head 
°f the femur, the acetabulum, and in the adult are firmly ossified to- 
gether, though in Anatomy they are described separately. 
The ilium is the upper, posterior and largest portion of the os innomi- 
natum, and presents for examination a crest, two faces and projections. 
The crest is the upper border of the bone, is sinuous in outline, resem- 
khng the italic letter S, is thinnest somewhere about the centre, and ter- 
nilnates in front in a projection, called the anterior superior spinous pro- 
Cess °f the ilium, which has just below it another projection, called ante- 
llor inferior spinous process of the ilium; the two processes being 
SeParated by a notch. Some anatomists say the ilium has an anterior 
border occupied by the anterior inferior spinous process, the notch above 
and the articular surface of the pubes below it. The crest terminates 
ehind in a projection known as the posterior superior spinous process 
the ilium, separated by a notch from a similar projection below it, the 
Posterior inferior spinous process of the ilium, below which is the greater 
sacro-sciatic notch. 
Ilium. 
The surfaces of the ilium are external and internal. The external sur- 
fece is called the dorsum ilii, and extends from the crest to the acetabu- 
-111 • It is concave posteriorly for more than half its extent, and convex 
anteriorly. It presents three linear elevations, called the curved lines of 
dorsum ilii, superior, inferior and middle. Of these lines the supe- 
lor is best marked, the others being indistinct. The superior curved 
e extends from the upper margin of the great sacro-sciatic notch nearly 
'ertically to the crest. The middle begins near the same point, generally 
. a groove and, curving upward and forward, terminates near the ante- 
ri°t extremity of the crest. The inferior commences near the anterior 
Extremity of the great sacro-sciatic notch, and terminates about the an- 
ter’°r inferior spinous process. 
The internal face of the ilium is in front concave and smooth; this por- 
lon being called the iliac fossa. Behind the fossa, and separated from it 
J a ridge, is an ear-shaped surface for articulation with the sacrum; be- 
llnd this is a rough surface. 
The Ischium. 
The ischium is the lowest portion of the os innominatum, and consists 
a body, ramus and tuberosity. 
The Body presents three faces and two borders. The internal surface 
ls smooth, sloping, triangular or quadrilateral, flat or slightly concave. 26 
Notes on Anatomy. 
and broader above than below. The external face presents a part of 
the acetabulum and just below it a deep horizontal groove. The poste- 
rior face is convex and quadrilateral. 
The posterior border presents a prominence called the spine of the 
ischium, above which is a part of the greater sacro-sciatic notch; below 
the spine is a smaller depression, called the lesser sacro-sciatic notch. 
The anterior border is sharp and thin, and forms the posterior bound- 
ary of a foramen called the thyroid, or obturator foramen. 
The tuberosity is the thick, prominent, rough lower portion of the 
ischium, upon which the trunk rests in the sitting posture, and is marked 
by muscular and ligamentous attachments. 
The ramus of the ischium passes upward and inward from the tuber- 
osity, forming a part of the anterior boundary of the obturator foramen, 
and meets the descending ramus of the pubes; the point of union being 
marked by a ridge. 
Pubes. 
The pubes, or os pubis, is the front portion of the os innominatum, and 
consists of a body and ramus. 
The body is the horizontal portion extending from the acetabulum to 
symphysis pubis. The symphysis pubis is the surface by which the 
bones of opposite sides articulate, through the intervention of cartilage; 
it is rough and marked by osseous projections, oval in outline, with the 
large end upward and its long diameter downward and backward. At 
the inner termination of the body, just at the upper extremity of the 
symphysis, is the angle of the pubes; extending outward from this, on 
the upper border of the body, is a rough ridge, about three-fourths of an 
inch in length, called the crest, which terminates in a projection called 
the spine; external to this is a triangular surface, the pectineal triangle, 
having its apex at the spine and its base outward at a bulge called the 
pectineal eminence; the triangle is bounded behind by a ridge, the pecti- 
neal line; in front it is limited by the anterior surface of the body. 
The lower border of the body forms the upper boundary of the obtu- 
rator foramen and presents a deep groove, running obliquely from with- 
out inwards and forward. The posterior face is smooth and concave. 
The anterior face is rough and becomes flat towards the symphysis, 
narrow and convex externally. 
The ramus of the pubes passes downwards and outward from the sym- 
physis to meet the ramus of the ischium. 
Besides those already described, the os innominatum presents two other 
appearances of great importance—the Acetabulum, or cotyloid cavity, 
and the Thyroid, or Obturator Foramen, Osteology. 
27 
The acetabulum, or cotyloid cavity, is situated on the outer face and 
at the point of union of the three bones. They furnish unequal propor- 
hons to it; the ilium gives rather less than two-fifths; the ischium rather 
teore than two-fifths; and the pubes one-fifth. It is a deep articular 
cavity corresponding to the head of the femur with which it articulates ; 
l*lB surrounded by a prominent rim, which is wanting at its lower inner 
Parh leaving a notch called the cotyloid; in the bottom near this notch 
18 a rough depression, intended to receive, in the living subject, a mass of 
iatty tissue. The acetabulum looks downward, forward and outward. 
Acetabulum. 
Obturator Foramen. 
The obturator or thyroid foramen, is situated in the front inner 
Part of the os innominatum and is bounded as follow’s; behind, by 
’•he anterior border of the body of the ischium; in front, by the ramus 
°f the ischium below and the ramus of the pubes above ; above, by the 
border of the body of the pubes ; below, it terminates at the junc- 
b°n of the body and ramus of the ischium. 
It is more or less triangular in shape, observably more so in the female 
than in the male; its base is above and apex below ; its long diameter is 
downward and outward. In the living subject it is closed by a strong 
connective tissue membrane, which bears the name of the foramen. 
SUMMARY. 
0s Innominatum—llium—Superior border or crest; sinuous, thinnest 
about the centre—two spinous processes—Superior Anterior and Supe- 
n°f Posterior, Anterior border—upper half has anterior superior spinous 
Pr°cess, notch and anterior inferior spinous process—lower half continu- 
°Us with pubes and enters acetabulum—Posterior border—Posterior 
SuPerior and inferior spinous processes, notches, greater and lesser sacro- 
-Bciatic notches. 
dorsum, or external face—convex anteriorly, concave more than half 
Posteriorly; superior, middle and inferior curved lines, the surface ex- 
tends from crest to acetabulum. 
Internal face—iliac fossa ; pectineal ridge; auricular surface and rough 
snrface. 
Ischium—Body—lnternal surface, smooth, sloping, triangular, more or 
ess flat and narrowing below. 
External surface —Acetabulum and horizontal groove below. 
Posterior surface—convex and quadrilateral. 28 
Notes on Anatomy. 
Posterior Border—spine—greater and lesser sciatic notches. 
Anterior Border—sharp and thin. 
luberosity—Thick, rough, lower portion has muscular impressions. 
Ramus—runs upward and inward and joins ramus of pubes. 
Pubes—Body—Symphysis, rough, oval, long diameter downward and 
backward. 
Posterior Face—concave and smooth. 
Anterior Face—flat, rough internally, convex externally. 
Upper border—Angle, crest, spine, pectineal line triangle and emi- 
nence. 
Lower border—oblique groove. 
Ramus—descends downward and outward to join ramus of ischium. 
Pelvis. 
The pelvis is the cavity circumscribed by the sacrum, coccyx and 
two ossa innominata, containing in the living subject some of the small 
intestine, a part of the large intestine, and the genito urinary appa- 
ratus, in part. It is bounded behind by the sacrum and coccyx and 
throughout the rest of its extent by the ossa innominata. It is divided 
into two portions, the false pelvis and the true. The false pelvis is 
that portion between the two iliac fossae bounded behind by the sa- 
crum, while in front it has no bony wall. It extends from the crest 
of the ilium above to the pectineal line below. This pectineal line, 
also called linea-ilio-pectinea, is a prominent ridge extending around 
the os innominatum from the symphysis pubis to the sacro-iliac sym- 
physis. At the linea-ilio-pectinea the pelvis is suddenly contracted 
and the true pelvis begins. The plane circumscribed by the ilio-pec- 
tineal line is called, the brim or inlet of the pelvis, or superior strait 
of the pelvis. The true pelvis thus extends from this brim down- 
ward to what is called the outlet, or inferior strait of the pelvis. The 
outlet is limited in front by the lower end of the symphysis pubis; the 
arch formed by the divergence of the pubic rami being called the pubic, 
or sub-pubic arch. Behind, the outlet is limited by the tip of the coccyx. 
Laterally the outlet is bounded by the tuber ischii. The pelvis is so 
attached to the vertebral column as to render the plane of the inlet 
oblique, from behind downward and forward, and so great is this obli- 
quity that the top of the symphysis pubis is about four inches below the 
level of the promontory of the sacrum. The so-called axis of the supe- 
rior strait is an imaginary line, perpendicular to the plane of the brim 
and cutting it at its centre. The true pelvis is much deeper behind than 
in front, measuring posteriorly five inches, laterally three and one-half Osteology. 
29 
lnches, and at the pubes one and one-half inches. Besides these meas- 
urements, obstetricians employ others, as of the outlet and inlet, called 
diameters. The diameters usually given are for the inlet, antero-poste- 
rior> transverse and oblique; for the outlet antero-posterior and trans- 
verse. 
The objects observable on the exterior of the pelvis are as follows : in 
front the symphysis pubis and below this the pubic arch ; on either side 
obturator foramen, farther out the acetabulum; behind this the 
greater and lesser sciatic notches, separated by the ischiatic spine; on the 
Centre behind is the sacral spine. 
The pelvis differs in the two sexes; the characteristic points in the 
female are as follows : ist, the thyroid foramen is more distinctly triangu- 
fef; 2d, the pelvis is more capacious—measuring more transversely and 
amero-posteriorly, but less vertically; 3d, the angle of the pubic arch is 
heater by io°, measuring from 90° to ioo°. 
The pelvis in the negro is observably smaller than in the Caucasian. 
Femur. 
The femur, or thigh bone, forms the skeleton of the thigh, which is the 
Segment of the limb between the hip joint above and the knee below, 
fe is the longest bone in the body, and is divisible into a shaft and two ex- 
tremities. 
The Upper Extremity is terminated by an articular head which is re- 
vived into the acetabulum. The head forms about two-thirds of a 
sPhere, and has just below and behind its centre a rough depression. 
Supporting the head is the neck, which is oblique in the adult, but be- 
c°nies nearly horizontal in old age; it is constricted just below the head, 
ut greatly enlarges as it approaches the shaft ; the lower border of the 
neck is nearly twice as long as the upper; its vertical diameter is 50% 
Sweater than its antero-posterior. The upper border of the neck termi- 
nates below at a prominent process, projecting upward, and called the 
trochanter major. The outer surface of the great trochanter is rough 
and marked by muscular impressions; at the inner side of its base is a 
depression called the digital fossa. 
The lower border of the neck terminates below at the smaller pro- 
jection known as the trochanter minor, which is situated on the inner 
side of the bone. Passing between the two trochanters behind is a 
rough ridge called the posterior inter-trochanteric line. Extending 
downward and inward from the front of the greater trochanter, and pass- 
lng below and in front of the lesser trochanter, is another ridge called 
the spiral line of the femur, or, by some, the anterior inter-trochanteric 30 
Notes on Anatomy. 
line. Some anatomists say that a rough ridge descends, for two inches, 
from about the middle of the posterior inter-trochanteric line and call it 
the linea quadrati. It is invisible. 
The lower extremity expands laterally and presents a broad articular 
surface, divided into two condyles, internal and external, by an antero- 
posterior depression, which is deep and rough behind and called, in this 
part, the inter-condyloid notch; but in front it is shallow and articular 
and forms, with the condyle on either side, a trochlea. The two condyles 
are dissimilar ; the outer is broader, its articular surface extends higher 
up in front, and when the femur is held vertically on a plane surface it is 
seen to be some half an inch shorter than the inner, this being due to 
the fact that the anatomical position of the femur is not vertical, but its 
lower extremity approaches its fellow very closely, whereas the upper 
extremities are separated by the width of the pelvis. On the outer side 
of the outer condyle is a prominence, the outer tuberosity, having just 
below a rough groove for the origin of a muscle, the poplileus. On the 
inner side of the inner condyle is a similar projection, the inner tuber- 
osity. Looking at the posterior aspect of the two condyles, there is 
seen on each, just above its articular surface, a slight depression for the 
origin of a corresponding head of the gastrocnemius muscle. 
The shaft of the femur is triangular on cross section, and is percepti- 
bly bowed forward. It has three surfaces and three borders. The sur- 
faces are two lateral and an anterior; the lateral surfaces are slightly con- 
cave; the anterior convex and smooth. The borders are two lateral, 
which are rounded, and a posterior, which is always known as the linea 
aspera. The linea aspera is rough, prominent and lipped; below, at the 
lower third of the femur, it divides into two lines, the two condyloid 
ridges, which diverge to the condyles, leaving a triangular interval on the 
back of the lower part of the femur. Just below the apex of this triangle 
the internal condyloid ridge is crossed obliquely by a broad, shallow 
groove, produced by the passage of the femoral artery. The outer con- 
dyloid ridge is the more prominent. About the upper third of the femur 
the linea aspera divides into three lines—ist, one to the base of the great 
trochanter; 2d, one to the lesser trochanter; 3d, one which, passing in 
front of the trochanter minor, becomes the spiral, or anterior inter-tro- 
chanteric line. 
SUMMARY. 
Upper Extremity—Head two-thirds sphere, pit, neck, two trochanters, 
two inter-trochanteric lines. Neck, oblique, contracted below head, then 
enlarged. Lower border longer—vertical diameter greater. Great tro- 
chanter convex and rough externally, pit within and behind. Osteology. 
31 
Lower Extremity—Two condyles, trochlea, inter-condyloid fossa. 
Tuberosity on each condyle; below the outer a groove. Outer condyle 
broader and shorter. 
Shaft—Directed obliquely downward and inward Anterior Face con- 
'ex; Lateral faces slightly concave. Borders—Two lateral rounded— 
Posterior is linea-aspera; .divides below into two condyloid ridges, one 
to each condyle; above, into three ridges, one to each trochanter and one 
to spiral line. 
Tibia. 
The skeleton of the leg, which extends from the knee to the ankle, 
c°nsists of two bones placed side by side and of unequal size; the tibia, 
°r inner bone, being twice the size of the outer bone, or fibula. 
The tibia, like all long bones, consists of a shaft and two extremities. 
The upper extremity bears upon its summit two shallow articular cavi- 
tles> situated beside each other and called glenoid cavities, these receive 
|be condyles of the femur, and in correspondence with them, are dissimi- 
ar> the outer being about circular and the inner oval. Between the 
glenoid cavities is a bifurcated projection, the spine. On the front of the 
°ne> about one and one-half inches from the upper limit, is a large pro- 
ess> called the anterior tubercle of the tibia, smooth above and rough 
e °w; above this the surface is smooth and triangular. The portion of 
bone on which the glenoid cavities rest, projects laterally and is known 
as a tuberosity, internal and external. The internal tuberosity presents 
a horizontal groove; the external, a circular, articular facet, posteriorly, 
0r articulation with the fibula. 
The lower extremity is four sided, one-half the size of the upper and 
§rooved posteriorly; projecting downward from the inner side is a pro- 
Cess) called the internal malleolus, with its inner face rough and convex, 
outer face triangular and articular, and its posterior border grooved. 
On its summit the lower extremity has a quadrilateral articular surface, 
with the one on the outer face of the internal malleolus; it 
ofS a s%ht antero-posterior ridge across its centre. On the outer side 
the lower extremity is a rough depression, extending upward an inch 
s°; this depression sometimes terminates below in a narrow articular 
surface. 
shaft is three sided, having an internal, external and posterior sur- 
O) an anterior and two lateral borders. The internal face is convex and 
cutaneous. The external face is concave above and becomes convex 
ad anterior below. The posterior face has, at its upper part, an oblique 
Re running downward and inward, called the popliteal line; above this Notes on Anatomy. 
is a triangular surface called the popliteal triangle. Running down the 
centre of the posterior face, from the popliteal line, is a vertical ridge. 
The anterior border, known as the crest, is sharp, prominent and sinu- 
ous. Of the two lateral borders, the external is much the sharper and 
more prominent. 
SUMMARY. 
Upper Extremity—lnner tuberosity grooved; outer flat, articular facet 
behind; outer gleniod cavity circular; inner oval; Spine—anterior tuber- 
cle, triangular flat surface. 
Lower Extremity—Square, half size of upper, grooved posteriorly. 
Articular cavity crossed by antero-posterior ridge. Outer side, rough 
depression, which may terminate below in articular facet. Inner side in- 
ternal malleolus, whose inner face is convex, subcutaneous and rough, 
whose outer face is triangular and articular, and whose posterior border 
is grooved. 
Shaft—Internal face convex and subcutaneous; outer face concave 
above and anterior below; posterior face, popliteal line and triangle, and 
below a vertical ridge. Anterior border sharp and prominent, sinuous 
and called crest or shin. Of the lateral borders, external is the more 
prominent and sharp. 
Patella 
The patella, or knee pan, is found on the front of the knee joint. It 
is really nothing more than a sesamoid bone developed in the tendon of 
the triceps extensor cruris. It is somewhat heart-shaped, the large end 
being up. It presents two faces; the anterior surface is convex and 
rough ; the posterior is articular, presenting two portions separated by a 
vertical ridge. These are intended to play on the condyles of the femur, 
and, in correspondence with the shape of the latter, are of different size, 
the outer being much the larger. The outer edge is the thinner. 
Fibula. 
The fibula is the outer bone of the leg, and, like all long bones, is 
divisible into a shaft and two extremities. The upper extremity is more 
or less globular, presenting on its inner face a round, slightly concave, or 
flat articular facet to articulate with the one found on the outer tuber- 
osity of the tibia; the outer aspect is rough and convex; a styloid pro- 
cess projects upward from it. 
The lower extremity is generally known as the external malleolus. It 
is more or less distinctly triangular ; its outer aspect is rough and subcu- 
taneous; its inner is articular, above which is a deep, rough surface, be- Osteology. 
low which is a rough depression; its anterior border is narrow and con- 
Vexi its posterior, broad, rough and vertical. 
The shaft is twisted, and presents three faces, which change their rela- 
te positions in different parts of the bone. Superiorly the faces are 
external, internal and posterior, the internal face being concave; as they 
Ascend the external face becomes posterior, the posterior becomes inter- 
_ > and the internal becomes anterior. On the latter is a sharp vertical 
ri(%e for the interosseous membrane. 
SUMMARY. 
Tpper Extremity—Rounded, circular facet on inner aspect. External 
ace convex and rough. Styloid process above. 
Lower Extremity, or External Malleolus—Triangular ; external face 
convex and rough ; internal face, articular facet above and deep, rough 
Pll below ; anterior border narrow, posterior broader. 
Shaft—External face becomes posterior below. 
Posterior face becomes internal below. 
Internal face becomes anterior below. 
Internal is concave, and has interosseous ridge. 
Foot. 
The foot bears a strong resemblance to the hand, differing essentially 
°nt it, however, in. that it is at right angles to the leg. It is arched both 
orn before backward and from side to side, and consists of tarsus, 
Metatarsus and phalanges. 
Tarsus. 
tarsus consists of seven bones : os calcis, astragalus, scaphoid, 
cuboid and the three cuneiform bones—external, middle and internal. 
Os Calcis. 
This bone forms the posterior abutment of the arch of the foot and is 
own as the heel bone. It presents two extremities and four surfaces. 
e upper surface consists of two portions, one behind the other; the 
Posterior portion is a rough rounded border; the anterior portion pre- 
fents two articular surfaces, separated by an oblique groove; this groove 
called the sulcus calcanei; the facet behind this is large, quadrilateral 
aud convex; the one in front small, oval and concave. The inferior sur- 
e 18 rough and presents, towards its posterior termination, two 
erosities, one external and the other, much longer, internal. The 
external surface is convex with two grooves separated by a ridge. The 
s Notes on Anatomy. 
internal surface is concave and grooved. The posterior extremity is 
called the posterior tuberosity; it is smooth above and rough below. 
The anterior extremity is articular and concavo-convex. 
Astragalus. 
The astragalus lies between the tibia above and the os calcis below, 
and, like the latter, presents four surfaces and two extremities. 
The superior surface is a trochlea for articulation with the tibia. The 
inferior surface is articular, and is divided into two facets by an oblique 
groove called the sulcus tali; this surface, articulating with the upper 
surface of the os calcis, is correspondingly formed, the facet behind the 
groove being large, square and concave, that in front small, oval and 
convex. When the two bones are articulated the sulcus calcanei and the 
sulcus tali form a canal called the sinus tarsi. The internal face is articu- 
lar to a small extent for the internal malleolus. The external face pre- 
sents a large triangular facet for the external malleolus. The anterior 
extremity is a rounded articular head, supported by a constricted portion, 
the neck. The posterior extremity is narrow and notched. Thus it is 
seen that every aspect of the astragalus, except the posterior, presents 
an articular surface. 
Cuboid, 
The cuboid lies between the os calcis behind and the fourth and fifth 
metatarsal bones in front. It is described as having four surfaces and two 
extremities. The upper surface is rough and flat. The lower surface is 
rough with a deep groove; behind this groove is a ridge. The outer 
surface is narrow, notched and rough. The inner surface is square, 
broad and articular above. The anterior extremity has two articular 
facets separated by a vertical ridge. The posterior extremity is a con- 
cavo convex articular surface. 
Scaphoid. 
The scaphoid receives the head of the astragalus behind and articulates 
in front with the three cuneiform bones. It presents two surfaces, two 
borders and two extremities. The posterior surface is concave and ar- 
ticular. The anterior surface presents three articular facets separated by 
two vertical ridges. The superior border is broad and rough; the in- 
ferior narrow and rough. The inner extremity is bluntly pointed and is 
called the tuberosity of the scaphoid; the outer is broader and some- 
times articular, above, for the cuboid. 
The three cuneiform bones, the remaining bones of the tarsus, lie in a 
transverse row between the scaphoid, behind, and the first, second and Osteology. 
35 
third metatarsal bones, in front; between the cuboid externally and the 
lnner border of the foot, internally. 
Internal Cuneiform. 
The internal cuneiform, like the other two, is of an irregular wedge 
shape and lies on the inner side of the tarsus, between the first metatarsal 
°ne and the scaphoid and has to its outer side the middle cuneiform. 
is the largest of the cuneiform bones and has its base below. 
The inner face is rough and convex, and has at the anterior, inferior 
angle a smooth facet, over which a tendon plays. The external face is 
c°ncave, and at its upper posterior part is articular. The posterior face 
articular and concave and smaller than the anterior. The anterior face 
|s articular, convex and kidney shaped. The inferior face is rough and 
18 the base of the bone; it presents at its posterior part a tuberosity. The 
SuPerior face is narrow and rough. 
Middle Cuneiform. 
The middle cuneiform lies between the inner cuneiform on the inner, 
and the outer cuneiform, on the outer side; between the scaphoid, behind, 
and the second metatarsal in front. It is the smallest of the cuneiform 
°nes and has its base above. It does not reach as far forward as the 
°ne on either side, thus leaving a cavity in front into which is received 
base of the second metatarsal bone. The internal face has two ar- 
bcular facets, meeting at an angle. The external face has one articular 
facet. 
External Cuneiform 
The external cuneiform is next in size to the internal and lies between 
e middle cuneiform, internally, and the cuboid, externally, and the 
ScaPhoid, posteriorly, and the third metatarsal, anteriorly. Its base is 
above. 
Metatarsus. 
The metatarsus consists of five bones stretching from the tarsus, behind, 
to the phalanges, in front, these bones are known by number, beginning 
the bone on the inner side. They are long bones, and, of course, 
ave a shaft and two extremities: the posterior extremity is called the 
ase and the anterior, the head. They grow distinctly smaller towards 
their anterior extremities. 
The first metatarsal bone is the largest, although the shortest. Like the 
°thers it presents an articular surface on the summit of its base, but has 
n°t generally, as the others have, lateral facets, for it does not articulate 36 
Notes on Anatomy. 
with the second metatarsal bone. The lower aspect of the base presents 
a rough prominence. 
The anterior extremity, like that of the others, furnishes an oblong 
articular head, or condyle. On the lower aspect of this extremity is a 
ridge separating two grooves. 
The second metatarsal bone is the longest and is next in size to the 
first. Its base is received into the interval between the internal and ex- 
ternal cuneiform bones. 
The fifth metatarsal bone can be distinguished from the others by 
having an articular facet on but one side of its base; all the rest, except 
the first, being articular on both sides. It is the smallest and has on the 
outer side of its base a prominent process. 
Phalanges. 
The phalanges of the toes, like those of the fingers, are arranged in 
three rows, except that the great toe has, like the thumb, but two phal- 
anges, the place of the second being taken by an ungual. They re- 
semble those of the hand so closely that a separate description is not 
called for. Except those of the great toe, they are smaller than in the hand; 
the shaft of the second row being scarcely more than a neck. 
The Skeleton of the Head. 
The skeleton of the head, or skull, consists of two portions, the bones 
of the cranium and those of the face. 
Cranium 
The cranium is the upper posterior division of the skull, and is formed 
by the union of eight bones—occipital, frontal, sphenoid, ethmoid, two 
parietal and two temporal. These become securely ossified together in 
mature life, and can be separated only in the young subject. 
Occipital. 
The occipital bone is situated at the posterior part of the cranium, and 
presents for examination two surfaces, four angles and four borders. 
The posterior surface, sometimes erroneously called external, is con- 
vex, and presents above its centre an eminence called the posterior 
occipital protuberance, sometimes also wrongly called external; curving 
outward from this on either side is a rough ridge called the superior 
curved line; passing downward from the protuberance to a large aper- 
ture—the foramen magnum—is a sharp ridge, the occipital crest; arching 
outward on either side from the middle of the crest, and concentric with Osteology. 
37 
lhe superior curved line is the inferior curved line. At the lower termi- 
nation of the crest is seen the foramen magnum, a large oval opening, 
having its antero-posterior diameter the longer and its larger end behind. 
On either side of the front half of the foramen magnum is seen the con- 
dyle for articulation with the superior articular process of the atlas; it 
Is oval, convex, articular, and directed obliquely forward and inward. 
Just behind the condyle is a depression, the posterior condyloid fossa, 
Wlth occasionally a foramen opening into it—the posterior condyloid, 
foramen. In front of the condole is the anterior condyloid foramen. 
Massing outward from the condyle is a rounded elevated ridge, the trans- 
verse process. On the inner aspect of the condyle is a tubercle. In front 
°f the foramen magnum is the basilar process; it is horizontal, quadri- 
foteral, convex, and presents an antero-posterior ridge, the pharyngeal 
sPine. 
The anterior face is concave and presents four ridges, meeting at right 
an§les, about the centre, called the crucial ridge, or occipital cross; each 
ridge is called an arm of the cross. Three of these ridges are grooved; 
while the fourth, which is the inferior, is sharp and not grooved until it 
aPproaches the foramen magnum. At the point where the four arms meet 
there is an eminence called the anterior occipital protuberance. Above 
each lateral arm of the cross there is a shallow depression, the cerebral 
fossa; below each lateral arm is another depression, the cerebellar fossa. 
the termination of the lower arm is the foramen magnum, and on each 
Slde of this the anterior condyloid foramen. In front, and to each side of 
the foramen magnum is a smooth broad groove for the termination of the 
foteral sinus. In front of the foramen magnum is the basilar process, 
vvhich, as on its inferior surface, is nearly horizontal and quadrilateral, 
hut is here concave to sustain the medulla oblongata. 
The angles are superior, inferior and two lateral. The lateral angles 
are each situated where the groove in the lateral limb of the crucial ridge, 
stnkes the border of the bone. The inferior angle is the truncated ex- 
tremity of the basilar process, and articulates with the body of the 
sphenoid. 
The superior angle juts into the interval formed by the union of the 
Posterior superior angles of the parietal bones. 
. borders are two superior and two inferior—Each superior border 
18 serrated for articulation with the parietal bone. 
Each inferior border articulates with the temporal bone, mastoid and 
Petrous portions; it is interrupted about its centre by a protuberance, 
the jugular eminence, in front of which is a depression; the jugular fossa. 38 
Notes on Anatomy. 
summary. 
Posterior surface—convex, posterior protuberance, crest; superior and 
inferior curved lines, foramen magnum, which is large, oval, long diame: 
ter, antero-posterior, large end behind; condyles, each convex, oval, 
directed obliquely inward and forward, anterior condyloid foramen, pos- 
terior condyloid fossa, and, perhaps, foramen; tubercles for check liga- 
ment, transverse process, basilar which is square, horizontal, con- 
vex and has pharyngeal spine. 
Anterior surface—concave, anterior protuberance, crucial ridge, with 
all its limbs grooved except the lower, cerebral and cerebellar fossae, fora- 
men magnum, anterior condyloid foramen, groove for the lateral sinus, 
basilar process, which is here square and concave. 
Angles—superior, inferior and two lateral. 
Borders—two superior serrated for parietal bones, two inferior serrated 
for temporal bone, each interrupted about the centre by jugular eminence 
and in front of this is the jugular fossa. 
Parietal. 
The two parietal bones form the upper and most of the lateral wall of 
cranium, and are situated between the frontal and occipital bones, in front 
and behind, and the two temporal bones laterally. Each bone is divided 
into two surfaces, four borders and four angles. 
The external surface is convex and presents a decided bulge about the 
centre, the parietal eminence; through this is seen running the temporal 
ridge, arching across this bone from the frontal; below the ridge, is the 
temporal fossa. Near the posterior superior angle is seen the parietal 
foramen, which is frequently absent. 
The internal surface is mostly concave and is sunken in the centre into 
a fossa. It is marked by digital pits for lodging cerebral convolutions, 
and the arborescent furrows worn by the arteries. Along the edge of the 
superior border is seen the half of a groove, completed by the opposite 
bone, and formed by the longitudinal sinus. 
The borders are four. The anterior, for articulation with the frontal 
bone, and the posterior, for the occipital, are serrated. The superior 
border,for articulation with its fellow, is straight, serrated and thick. The 
inferior border, for articulation with the squamous portion of the tempo- 
ral bone, is short, curved and beveled at the expense of the outer table. 
The angles are four. The anterior superior and the posterior superior 
are right angles. The anterior inferior is long, thin and marked on its 
inner aspect by a furrow formed by the middle meningeal artery. The Osteology. 
39 
Posterior inferior is blunt and usually marked internally by the groove 
for the lateral sinus. 
External Surface—convex; parietal eminence, temporal ridge, tempo- 
rfo fossa ; parietal foramen. 
Internal Surface—concave; pitted, furrowed, grooved by superior 
longitudinal sinus. 
SUMMARY. 
Borders—Anterior and posterior serrated. Superior, straight, thick 
and serrated. Inferior, short, arched and thin. 
Angles—Anterior Superior and Posterior Superior are right angles. 
Anterior Inferior, prolonged and furrowed internally. Posterior Inferior, 
blunt and grooved within by lateral sinus. 
Frontal. 
The frontal bone is situated at the front and base of the cranium. In 
early kfe the bone consists of symmetrical lateral halves, separated by 
an unformed suture, which, however, becomes ossified later in life, though 
the bone could still be described as consisting of two similar lateral per- 
sons. The bone is described as being made up, in each of its lateral 
balves, of two portions—the vertical, or frontal, and the horizontal, or 
Orbito-nasal portion. 
The vertical portion forms the skeleton of the forehead and presents two 
surfaces and a lateral aspect. Upon the anterior surface, which is convex, 
foere are seen superiorly a smooth, somewhat flattened surface; below this 
a bulge,called the frontal eminence; below this a broad,shallow,transverse 
groove ; below this a transverse ridge, the superciliary; between this and 
foe opposite ridge, bn the middle line, is a prominence called the glabella, 
0r nasal tuberosity. Below the superciliary ridge is seen the margin of 
foe orbit, called the supra-orbital ridge, which terminates at the inner 
extremity in the internal angular process, and at its outer in the external 
angular process. About the inner third of the supra-orbital ridge is a 
n°tch, sometimes formed into a foramen, called the supra-orbital notch or 
foramen. 
The posterior face of the vertical portion is concave and marked by 
digital pits and arborescent furrows for the arteries. In the middle line 
fo's surface presents superiorly a groove for the longitudinal sinus, which, 
as b descends, terminates in a ridge, at the extremity of which is a small 
foramen, called the foramen coecum. 
The lateral aspect of the bone presents a ridge curving upward and 
backward from the external angular process, and called the temporal 
ridge; below this the surface is sunken and forms part of the temporal 40 
Notes on Anatomy. 
fossa. Both the temporal ridge and fossa are only partially seen on the 
frontal bone, for, in the articulated skull, they are continued on to the 
parietal and temporal bones. 
The horizontal portion consists of two lateral parts, the orbital plates, 
separated by a rectangular notch, the ethmoidal fissure. Each orbital 
plate presents an inferior and a superior surface. The inferior face is 
smooth, triangular and concave, the concavity being greatest behind the 
externa] angular process—the lachrymal fossa. It has, just within the 
supra orbital notch, a depression called the fovea trochlearis. 
The upper surface of the orbital plate is convex and rough, presenting 
irregular rough eminences. 
The ethmoidal fissure is the rectangular notch separating the two orbi- 
tal plates. In front of it is a roughened interval, between the two inter- 
nal angular processes, called the nasal notch, descending from the centre 
of which is a long pointed process, the nasal spine. Upon the posterior 
surface of the nasal spine is a vertical ridge, on either side of which is a 
furrow and external to this an irregular opening leading to a hollow in 
the vertical portion called the frontal sinus. The frontal sinus, one on 
each side of the middle line, is an irregular cavity between the two tables 
of the vertical portion and gradually increases in size from the time it 
makes its appearance in early life. 
The borders of the frontal bone are two—superior and inferior. The 
superior border is semicircular and serrated for articulation with the 
parietal bones. When examined closely it is seen to be bevelled superi- 
orly at the expense of the inner table, and inferiorly at the expense of 
the outer. 
The inferior border is the posterior termination of the orbital plates, 
interrupted in the centre by the ethmoidal notch. It is straight and ar- 
ticular with the lesser wing of the sphenoid. 
At the angle of the junction of the two borders, there is a rough tri- 
angular surface, the sphenoidal triangle, for articulation with the greater 
wing of the sphenoid. 
SUMMARY. 
Vertical portion—Anterior face—convex; flat surface; frontal eminence; 
groove; superciliary ridge ; nasal tuberosity ; supra-orbital ridge; inter- 
nal and external angular processes ; supra-orbital foramen. 
Posterior face—concave; pits; arterial furrows ; central groove ; ridge; 
foramen coecum. 
Horizontal, or orbito—nasal portion—two orbital plates and the eth- 
moidal fissure. Osteology. 
41 
Inferior surface—triangular, smooth, concave, fovea trochlearis. 
Superior Surface—convex and rough. 
Ethmoidal Fissure, nasal notch, nasal spine, ridge, on each side a groove 
and opening of frontal sinus.' 
Lateral aspect—temporal ridge and fossa. 
Borders—Superior semicircular and serrated. Inferior straight and 
lnterrrupted by ethmoidal fissure. 
At angle of union of two borders, a rough surface for greater wing of 
sphenoid, sphenoidal triangle. 
Temporal. 
The temporal bones are two, one to either side. Each bone is situated 
at the side and base of the cranium, its most prominent relation being 
derived from its position below the parietal. It is divided into three 
Portions, squamous, mastoid and petrous. 
Lhe squamous portion is the front upper thin part, forming the thin- 
nest part of the wall of the cranium. It presents for examination two 
Effaces and an upper, or semicircular border. The external surface is 
lightly convex, with arterial furrows and the extension on to it, from the 
Parietal, of the temporal ridge. The most noticeable appearance on this 
Lee is the zygomatic process, which springs from the lower part of the 
S(faamous portion, first juts outward, it then twists, and is directed for- 
Ward in a slightly oblique direction, receding from the bone a little as it 
advances; its external surface convex, its internal concave; its upper 
border is thin, the lower, thicker and slightly arched upward. Its an- 
teri°r extremity is slightly beveled off into a rough surface, for articula- 
b°n with the zygomatic process of the malar. The zygomatic process 
sPnngs from the external surface of the squamous portion by two roots, 
an anterior and a posterior; the anterior is a broad well-marked ridge 
Passing inwards to a smooth, rounded projection, the eminentia articu- 
Lris, which forms the front boundary of the glenoid fossa; the posterior 
r°ot divides into two branches, the upper is lost posteriorly in the tem- 
P°ral ridge, the lower—sometimes called the middle root of the zygoma 
Ascending to terminate in a slight prominence, the posterior glenoid 
process at a well marked crack, called the fissure of Glaser, which di- 
vides the glenoid fossa into two portions; that in front is smooth for the 
reception of the condyle of the lower jaw ; that behind is rough. The 
kEnoid fossa, as its name imports, is a concave surface, situated between 
*be roots of the zygoma, bounded in front by the eminentia articularis 
and behind by the middle root of the zygoma and the vaginal process 
0l the petrous portion, and divided as above stated, into two portions by 42 
Notes on Anatomy. 
the fissure of Glaser. Where the anterior and posterior roots meet, the 
zygoma presents a prominence, called its tubercle. 
The internal surface of the squamous portion is pitted and marked by 
arterial furrows. 
The superior border is irregularly semicircular and beveled, articula- 
ting above with the parietal and anteriorly with the greater wing of the 
sphenoid. 
The mastoid portion is the thick, posterior, cellular part of the tem- 
poral bone, and presents two surfaces and two borders. 
The external surface is convex, subcutaneous and rough; posteriorly it 
generally presents a small foramen called the mastoid; inferiorly it termi- 
nates in a rough nipple-like process, the mastoid. Just at the base of 
the internal aspect of the mastoid process is a depression, the digastric 
fossa, and just internal to this a groove, the occipital. 
The internal surface presents but one object, a groove for the lateral 
sinus, called the fossa sigmoidea. 
The borders of the mastoid portion are the superior, which articulates 
with the posterior inferior angle of the parietal bone; and the posterior, 
which articulates with the occipital bone. 
The petrous portion is a three-sided pyramid, its base being between 
and partly lost in the other two portions, from which it projects inward, 
forward and slightly downward, gradually tapering to its apex. It aids 
in the formation of the base of the skull, and is described as consisting 
of three faces, three borders, a base and an apex. 
The posterior face looks backward and presents but two points worth 
observation: ist, the internal auditory meatus, a large circular opening, 
situated about the middle of the face; 2d, behind and external to the 
internal auditory meatus is a small crack, leading to a canal, called the 
aqueductus vestibuli. 
The inferior, or basilar portion looks downward and presents nine 
points: ist. Near the centre a large round aperture, the carotid aper- 
ture of entrance. 2d. Internal to the carotid aperture is a rough 
quadrilateral surface extending to the apex of the bone. 3d. Be- 
hind the carotid aperture is a deep depression, the jugular fossa. 4th. 
Behind and external to the jugular fossa is an articular surface, the jugu- 
lar facet, for articulation with the jugular eminence of the occipital. sth. 
Near the posterior border, behind and slightly internal to the carotid 
aperture, and directly beneath the internal auditory meatus, is a small 
opening, the aqueductus cochleae. 6th. Passing downward, from a 
point about midway between the mastoid process and the carotid aper- 
ture, is a long tapering process, varying in size and direction, and called Osteology. 
43 
the styloid process; it is formed from a separate ossific centre and does 
not become ossified to the rest of the bone until after puberty; it is usu- 
ahy directed downward, forward and inward and connected by a ligament 
VVlth the hyoid bone. 7th. Embracing the base of the styloid pro- 
cess and extending from the auditory process, with which it is continuous, 
to the carotid aperture, is a narrow prominence, called vaginal process, 
Behind the base of the Styloid process, and between it and the 
Mastoid process, is a small opening, called the stylo-mastoid foramen. 
9th. Between that portion of the auditory process, which is continuous 
the vaginal process, and the mastoid process is a slight fissure, the 
auncular fissure. 
The anterior face looks forward and upward and presents five points: 
Ist- About the centre is the bulge of the superior semicircular canal. 2d. 
External to this is a depression, corresponding to the tympanum. 3d. Be- 
l°w the bulge is a groove leading to the hiatus Fallopii. 4th. External to 
this is a small groove, the petrosal, often not seen. sth. Near the apex is 
a depression, called the digital pit for the Gasserian ganglion. 
The base of the petrous portion is partly interposed between the other 
two portions and partly continuous with them. On the free portion is 
Seen the opening into the ear, the external auditory meatus, which is 
SltUated between the mastoid process behind and the middle root of the 
zygoma in front, and between the posterior root of the zygoma above 
and the auditory process below. The auditory process is a rough curved 
sheet of bone continuous with the vaginal process, and partly circum- 
scribing the external auditory meatus. 
The apex of the petrous portion is rough and presents a large irregu- 
ar aperture for the carotid artery. It is received between the basilar 
Process of the occipital bone and the spinous process of the sphenoid. 
The borders are three, superior, posterior and anterior. The superior 
13 sightly grooved for the petrosal sinus and notched near the apex by 
fifth nerve. 
The posterior border is interrupted about its centre by a projecting 
piece of bone which partially subdivides the jugular fossa. 
This border articulates with the occipital bone. 
The anterior border is the shortest, and where it is lost on the internal 
surface of the squamous portion, the remains of a suture are discernible. 
In the retreating angle formed between this border and the squamous 
Portion are seen two small apertures separated by a thin plate of bone, 
called processus cochleariformis; the upper aperture is for the tensor 
tympani muscle, the lower for the Eustachian tube. From the point 44 
Notes on Anatomy. 
where this border joins the squamous portion, it is free, separated from 
the spinous process of the sphenoid by a slight interval. 
SUMMARY. 
Squamous Portion—Front, upper, thin, semicircular; 
External Surface—Bulge, arterial grooves, temporal ridge, zygomatic 
process, first directed outward, then twisted and runs forward; concave 
internally, convex externally, upper border thin, lower thick and arched, 
bevelled and serrated at anterior extremity. Rises by two roots; ante- 
rior is eminentia arlicularis; posterior divides into two branches, upper 
lost in temporal ridge, lower turns downward to fissure of Glasser, tubercle 
at junction of the two roots. 
The Glenoid Fossa lies between the two roots of the zygoma from the 
eminentia articularis to the vaginal process, is crossed by fissure of Glas- 
ser and is smooth in front and rough behind. 
Internal Surface—Pitted, furrowed and concave. 
Superior Border—Semicircular, beveled, articulates with parietal bone 
above and greater wing of sphenoid in front. 
Mastoid Portion—External Surface—Rough, convex, mastoid foramen 
and process; digastric fossa : occipital furrow. 
Internal Surface—Fossa sigmoidea. 
Upper Border—Articulates with posterior inferior angle of parietal. 
Posterior Border—Articulates with occipital. 
Petrous Portion—Internal, intermediate, oblique, triangular and taper- 
ing. 
Anterior Face—Roof of middle ear, bulge of semicircular canal, hia- 
tus Fallopii, petrosal groove, digital pit. 
Posterior Face—Internal auditory meatus; aqueductus vestibuli. 
Basilar Face—Auricular fissure, stylo-mastoid foramen, styloid pro- 
cess, vaginal process, jugular fossa, jugular facet, carotid aperture, aque- 
duct of cochlea, rough surface. 
Superior Border—Faintly grooved. 
Posterior Border—Interrupted about centre by triangular tongue of 
bone. 
Anterior Border—Short; aperture of tensor tympani above, processus 
cochleariformis, and below it Eustachian aperture. 
Base—External auditory meatus and auditory process. 
Apex—Carotid aperture. 
Sphenoid Bone. 
The sphenoid is found in the centre of the base of the cranium, ar- Osteology. 
45 
tlculating- with all the other cranial bones and with five of those of the 
face. It is divided, for description, into a body two greater and two 
fasser wings and two pterygoid processes, and is said to resemble a bat 
its wings spread out. 
The body is the central portion of the bone, from which the other por- 
ous spring. It presents six surfaces, superior, inferior, anterior and pos- 
terior and two lateral. 
The superior, or cerebral face, has projecting forward a thin triangular 
Process called the ethmoidal spine, for it is received into the sphenoidal 
n°tch of the ethmoid. Passing backward from this1 on the middle line is 
a shght ridge, on either side of which the surface is slightly depressed ; 
at the posterior termination of the ridge is a transverse groove, the optic, 
terminating at each extremity in an opening, the optic foramen, just be- 
hind the optic groove, the surface is raised into a transversely oblong 
Novation, the olivary process or ridge, which usually presents at either 
s'de a tubercle called the middle clinoid process; behind the olivary ridge 
the surface is deeply sunken, and the depression is called the Sella Tur- 
ClCa; on either side of the Sella Turcica is a broad curved groove, the 
Cavernous or carotid groove, behind the Sella Turcica, the surface is quad- 
rifateral, slopes downward and backward and is called the dorsum ephip- 
P1!) which terminates in front at either side in a projection, overhanging 
the Sella Turcica, called the posterior clinoid process. 
The inferior surface presents a central longitudinal projection, the ros- 
trum, on either side of which is a thin plate of bone, the vaginal process, 
towards the outer part of which, visible from below, is a groove, the 
pterygo-palatine. 
The anterior surface shows a central projection passing from the eth- 
moidal spine to the rostrum, called the beak; on each side of this is seen 
the irregular opening into the cavity into which the body is hollowed; 
this cavity is divided by a medium septum. 
The posterior surface is rough, vertical, quadrilateral and articular for 
the extremity of the basilar process of the occipital bone, to which it 
becomes ossified early in life. 
Each lateral portion of the sphenoid bone consists of two parts called 
Sweater and lesser wings, both springing from the side of the body and 
are separated by an irregular triangular interval, the sphenoidal fissure, 
0r m the articulated skull, foramen lacerum anterius. 
The lesser wing projects outward from the front upper part of the side 
°f the body and is triangular in shape, having its base internal and per- 
forated by the optic foramen. Its anterior border is comparatively 
straight and serrated for articulation with the orbital plate of the frontal 46 
Notes on Anatomy. 
bone. Its posterior border is free and terminates internally in a projec- 
tion called anterior clinoid process. The upper and lower surfaces of 
the lesser wing are flat. 
The greater wing comprises the greater part of each lateral portion of 
the bone, extending outward from the side of the body, it springs from 
it by a narrow portion called the pedicle. It presents four surfaces, supe- 
rior, inferior, anterior and external. 
The superior or cerebral surface is smoothly concave and has on it 
three foramina in an antero-posterior row, situated a little external to the 
pedicle; they are known, from before backward as rotundum, ovale and 
spinosum. Rotundum opens in orbit and ovale and spinous below. 
The first two are of considerable size and derive their names from their 
shape, the last is small and derives its name from its situation in a rough 
process, which projects downward from the greater wing, called the 
spinous process. 
The anterior, or orbital surface is flat, smooth and quadrilateral, form- 
ing part of the outer wall of the orbit. It is bounded above by a ser- 
rated border for the frontal bone, below by a rounded border for the 
spheno-maxillary fissure, externally its border is serrated for the malar 
bone. 
The external surface consists of two parts—a vertical portion, which 
enters into the temporal fossa, and a horizontal portion, which is the 
inferior face, and aids in forming the zygomatic fossa; between these 
is a ridge called the pterygoid, which terminates anteriorly in a triangu- 
lar spine. Opening on the inferior face are the foramina ovale and spi- 
nosum. 
The pterygoid process stands downward on each side from the union 
of the body and greater wing. It consists of an inner and outer plate 
meeting in front at an acute angle, thus exhibiting between them, poste- 
riorly, a depression called the pterygoid fossa; the external plate is the 
shorter and much the broader; the internal plate is narrowband terminates 
below in a hook-like projection called the hamular process. Tracing up 
the posterior aspect of the internal plate, there is seen to commence, 
about or a little above its centre, an oblong depression called the sca- 
phoid fossa. Piercing the base of the pterygoid process is a foramen, 
called the pterygoid or Vidian. At the front of the base of the process 
extending upward, is a flat surface, forming the posterior wall of the 
spheno-maxillary fossa, upon which are seen the openings of two foram- 
ina—the pterygoid and rotundum—and a groove called the pterygo- 
palatine notch. The inner aspect of the internal plate is the outer 
boundary of the posterior opening of the nose. The two plates are sep- Osteology. 
47 
arated below by an angular interval, which is filled by the tuberosity of 
the palate bone. 
Parts—Body—Two lesser and two greater wings; two pterygoid pro- 
cesses. 
SUMMARY. 
Situation—Base and centre of the cranium. 
Body—Upper Surface—Ethmoidal spine; central ridge; lateral depres- 
Sl°n; optic groove; optic foramen; olivary ridge; middle clinoid pro- 
Cesses; sella Turcica; cavernous groove; dorsum ephippii; posterior cli- 
n°id processes. 
Lower Surface—Rostrum ; two vaginal processes; two pterygo-pala- 
tine grooves. 
Posterior Surface—Articular, rough and quadrilateral. 
Lesser Wing—Triangular; base pierced by optic foramen ; surface 
above and below flat; front edge straight and seriated; posterior edge 
smooth and concave, terminating internally in anterior clinoid process. 
Lhe space between the greater and lesser wings is the sphenoidal fissure, 
0r foramen lacerum anterius. 
Anterior Surface—Median septum and lateral cells 
Greater Wing—Arises by pedicle from side of the body. Upper or 
cerebral surface, concave; three foramina—rotundum, ovale, spinosum. 
Anterior face; quadrilateral, flat and smooth, and enters into outer wall 
°f orbit. Outer face; temporal fossa; zygomatic fossa, separated by 
Pterygoid ridge, which terminates anteriorly in a spine. Greater wing 
terminates behind in spinous process. 
Pterygoid Process—Outer plate broader and shorter. 
Inner plate—long and narrow, hamular process and scaphoid fossa. 
Pterygoid foramen, pterygoid fossa. 
Flattened surface above the process anteriorly, upon which are pterygo- 
palatine notch and foramina rotundum and pterygoid. 
Ethmoid Bone. 
The ethmoid bone is in the middle of the front of the base of the cra- 
nium and consists of a body and two lateral masses. 
The body is partially seen by looking from above on the base of the 
Cranium, for it lies in the ethmoidal notch of the frontal bone. 
The superior surface of the body is called the horizontal, or cribriform 
Plate, being perforated by numerous small foramina; these foramina are 
said to be arranged in three rows on each side of the middle line, extending 
from before backwards; the outer and inner rows are much more distinct 48 
Notes on Anatomy. 
than the middle, the foramina of which are small and irregular. These 
foramina are on a depressed surface, which is separated from the opposite 
one by a projection called the crista Galli, which extends upward from 
the superior surface; it commences toward the rear part of the surface 
and gradually rises in height towards the front; it is sometimes hollow 
with bulging sides, and it varies greatly in height and size. Projecting 
outward from the front of it are two small processes, one towards each 
side, called the alar processes. At each side of the base of the crista 
Galli is a small fissure .called the nasal groove, or slit. Posteriorly the 
superior surface presents a deep notch, the sphenoidal fissure, for the re- 
ception of the ethmoidal spine of the sphenoid bone. 
Laterally this surface articulates with the orbital plate of the frontal 
bone; anteriorly with the frontal bone by the two alar processes which 
complete, posteriorly, an opening called the foramen coecum. 
From the lower surface of the cribriform plate there passes downward, 
on the middle line, a thin sheet of bone called the perpendicular lamella, 
which aids in forming the septum of the nose, articulating in front with 
the nasal spine of the frontal and with the nasal bones; posteriorly it ar- 
ticulates above with the beak of the sphenoid, below with the vomer; 
inferiorly it gives attachment to the cartilage of the septum. Its faces 
are grooved. 
The lateral mass lies to the side of the perpendicular lamella, with a 
slight interval between; it presents an outer, inner and superior 
face. The outer surface forms part of the inner wall of the orbit; it is 
smooth, flat and quadrilateral and is called the osplanum ; its upper part 
is perforated by two canals, which are the anterior and posterior ethmoi- 
dal foramina. The internal surface is convex, rough and fissured behind; 
this fissure is called the superior meatus of the nose; above this a curved 
portion of the bone called the superior turbinated bone; below the supe- 
rior meatus is another portion called the middle turbinated bone, which 
is the upper limit of the middle meatus of the nose. The superior sur- 
face of the lateral mass presents numerous irregular openings into the 
cells, of which this part of the bone is made up; these are closed in by 
the overlapping horizontal plate. Projecting downward and backward 
from the lower edge of the lateral mass is a thin plate of bone called the 
unciform process, which articulates with the ethmoidal process of the in- 
ferior turbinated and helps to close the opening of the antrum maxillare. 
From the posterior extremity of the lateral mass there projects backward 
a triangular, curled pointed process, which extends into the sphenoidal 
cell of that side, and, as puberty approaches, becomes detached from 
the ethmoid and ossified to the sphenoid; it is called the sphenoidal spongy Osteology. 
49 
b°ne, or pyramid of Wistar. The cells, of which the lateral mass con- 
Slsts, are separated by a transverse septum into two sets, the anterior 
and posterior ethmoidal cells; the anterior communicate with the middle 
Meatus by a tortuous canal called the infundibulum, with which the frontal 
sinus also communicates; the infundibulum opens into the upper front 
Part of the middle meatus by a large orifice. At the upper back part of 
the superior meatus is an orifice which leads into the posterior ethmoidal 
cells. 
SUMMARY. 
Situation—Middle of front of the base of the cranium. 
Body—Superior Surface—Cribiform plate; crista Galli in centre; alar 
Processes; nasal groove; depression on each side, with three rows of fo- 
ramina; sphenoidal notch. 
Parts—Body and two lateral masses. 
Inferior Surface—Perpendicular lamella. 
Lateral Mass—Outer Surface—Osplanum, smooth, flat, quadrilateral. 
Internal Surface—Convex, rough; superior turbinated bone; superior 
Meatus; middle turbinated bone; unciform process. 
Superior Surface—Cellular; two canals; anterior and posterior ethmoi- 
dal foramina. 
The Bones of the Face. 
The bones of the face are fourteen, as follows: Two nasal, two lachry- 
mal, two malar, two superior maxillary, two palate, two inferior turbi- 
nated, one vomer, one inferior maxillary. 
Nasal Bones. 
The nasal bones are two small, flat bones, forming the bridge of the 
n°se, along the centre of which they articulate with each other. Each 
done is quadrilateral, presenting two surfaces, two extremities and two 
borders. 
The upper extremity articulates with the nasal notch of the frontal 
bone; it is thicker and narrower than the lower, which latter presents a 
notch. 
The anterior surface is broad and convex toward its lower part, while 
lts upper part is narrow and concave; this surface presents a foramen. 
The posterior face has on it a vertical furrow for the nasal nerve. 
The internal border is the shorter and when articulated with its fellow, 
Presents a crest, for articulation with the nasal spine of the frontal, and the 
Perpendicular lamella of the ethmoid. 
The external border articulates with the nasal process of the superior 
maxillary bone. 50 
Notes on Anatomy. 
Lachrymal Bone. 
The lachrymal bones are a pair of small bones, one being found on the 
inner wall of each orbit in front of the os planum. The bone remotely 
resembles a finger nail and hence acquires its synonym of unguis. It 
presents two faces, two extremities and two borders. The external face 
is divided into an anterior and a posterior portion, by a vertical ridge, 
which terminates inferiorly in a hook-like process called hamular. The 
posterior and larger portion is part of the inner wall of the orbit and 
is flat and smooth. The anterior portion is a vertical groove, called the 
lachrymal. 
The internal face is rough for articulation with the ethmoid bone, and 
presents a vertical groove corresponding to the vertical ridge on the op- 
posite side; the portion of the surface in front of this groove enters into 
the formation of the middle meatus. 
The upper extremity articulates with the internal angular process of 
the frontal bone. 
The lower extremity is divided into two parts, the posterior articula- 
ting with the orbital plate of the superior maxillary, the anterior project- 
ing farther downward and articulating with the lachrymal process of the 
inferior turbinated. The anterior border articulates with the nasal pro- 
cess of the superior maxillary bone. 
The posterior border articulates with the os planum. 
Inferior Turbinated Bone. 
The inferior turbinated, or inferior spongy bone, is found on the 
lower part of the outer wall of the nasal fossa; the middle and superior 
turbinated bones are merely parts of the ethmoid. The bone is divisible 
into two extremities, two faces and two borders. 
The anterior extremity is much the larger and articulates with the in- 
ferior turbinated crest of the superior maxillary. 
The posterior extremity is slender and pointed and articulates with the 
inferior turbinated crest of the palate bone. 
The external face is concave and enters into the inferior meatus of the 
nose. 
The internal face is convex and marked by apertures and grooves. 
The inferior border is rounded and free, marking the limit between the 
middle and inferior meatus. 
The superior border articulates from before backward with the superior 
maxillary, the lachrymal, the ethmoid and the palate bones. It presents 
three processes, lachrymal, ethmoid and maxillary. The lachrymal Osteology, 
51 
Process is directed upward to articulate with the lower extremity of the 
lachrymal bone, and with the nasal process of the superior maxillary, 
aiding to form the lachrymal canal. 
The maxillary process is larger than the other two and is a curved 
Plate of bone directed downward and outward from the base of the eth- 
moidal process and articulates with the superior maxillary by hooking 
around the orifice of the antrum. The ethmoidal process is behind the 
lachrymal, and is directed upward to articulate with the unciform process 
°f the ethmoid. 
Vomer. 
The vomer is a single bone found separating the nostrils behind and 
below, forming part of the septum of the nose; the upper part of the 
Septum is the perpendicular lamella of the ethmoid ; the anterior part is 
a plate of cartilage. It presents two faces and four borders. 
The faces are lateral and each forms part of the inner wall of a nos- 
tril> the bone usually bulging toward one or the other. They are 
marked by shallow furrows and by the naso-palatine groove, which is 
directed obliquely downward and forward on each face. 
The superior border presents an antero-posterior groove which receives 
tbe rostrum of the sphenoid bone; the edges of the groove are projected 
°utward into lips, or alae, each of which lies in the groove above the vagi- 
n&l process of the sphenoid bone. 
The inferior border is received between the everted edges of the palate 
Processes of the superior maxillary bones and of the horizontal plates of 
*be palate bones. 
The anterior border presents a longitudinal fissure which receives su- 
periorly the perpendicular lamella of the ethmoid, interiorly the triangular 
Cartilage of the septum; the lower part is occasionally not fissured but 
r°ugh. 
The posterior border is concave and free, terminating, posteriorly, the 
Septum of the nose. 
Malar Bone. 
The malar bone forms the prominence of the cheek, is somewhat 
Quadrangular and presents for examination four processes and a body 
Wlth two surfaces and four borders. 
The anterior, or external face is convex and has several foramina open- 
lng on it, called malar. 
The posterior, or internal face is smooth and concave, entering into the 
temporal fossa above and the zygomatic below. 52 
Notes on Anatomy. 
The frontal process projects upward to articulate with the external an- 
gular process of the frontal bone. 
The orbital process is a smooth projecting lip of bone curving down- 
ward from the frontal process, and projecting inward, forming a concavity 
which enters into the outer wall and floor ot the orbit. Its lower surface 
forms part of the temporal fossa. Superiorly it articulates with the frontal 
bone. Posteriorly it articulates with the sphenoid bone; internal to 
which it articulates with the orbital plate of the superior maxillary bone; 
between these two articulations there is often seen the narrow, rounded, 
non-articular anterior extremity of the spheno-maxillary fissure. This 
process presents the openings into one or more small canals, temporo- 
malar, which extend to the anterior surface of the bone and some usu- 
ally to the posterior surface. 
The maxillary process is rough and triangular, articulating with the 
superior maxilla. 
The zygomatic process stands backwards, is long and narrow and ar- 
ticular with the zygomatic process of the temporal. 
The superior border is concave, smooth and rounded, and forms part 
of the margin of the orbit. 
The inferior border is straight and continuous with the lower edge of 
the zygoma. 
The anterior border is straight and rough to articulate with the supe- 
rior maxilla. 
The posterior border is sinuous and continuous with the temporal 
ridge above, and below with the upper edge of the zygoma. 
Superior Maxillary, 
The superior maxillary bones form the upper jaw and are, with the ex- 
ception of the inferior maxillary, the largest bones of the face. Each 
bone articulates with the frontal and ethmoid, and all the bones of the 
face except the inferior maxillary. The bone is divisible into a body and 
four processes. 
The body is irregularly quadrilateral, is hollowed out into a cavity 
called the antrum of Highmore, or antrum maxillare, and presents four 
faces—anterior, superior, posterior, internal. 
The anterior or facial surface is somewhat concave and presents about 
its centre a depression, called the canine fossa, which is limited internally 
by a vertical ridge, the canine ridge; on the inner side of the canine 
ridge is another depression, the incisive fossa; just above the canine fossa 
is a foramen, the infra-orbital. This surface is limited internally by the 
thin concave edge of the nasal fossa; below by the alveolar process; ex- Osteology. 
53 
ternally by the malar process and a ridge descending from it; superiorly 
ky the margin of the orbit. 
The posterior or zygomatic surface is chiefly occupied by a rough 
ktfige, the tuberosity of the superior maxillary bone; it presents nume- 
r°us small foramina, and at its lower part a rough oval surface; above 
and internal to this is a smooth spiral groove, which, with a similar 
groove on the palate bone, forms the posterior palatine canal. The 
uPper limit of this surface, separating it from the orbital face, is a 
smooth rounded border, on which is a notch, the commencement of the 
!nfra orbital canal. The malar process separates this face from the an- 
terior; below it is limited by the alveolar process. 
The superior or orbital surface forms the floor of the orbit. It is 
formed of a thin triangular plate of bone, is smooth, sloping downward 
and forward, and marked from behind forward by a groove, the infra- 
°rbital canal, which disappears in the bone to terminate at the infra-or- 
fotal foramen on the anterior face. This face is bounded internally by a 
r°Ugh edge for articulation, from behind forward, with the palate, eth- 
ni°id, and lachrymal bones ; anteriorly it is limited by the lower margin 
the orbit, internally, and, externally, by a rough border for articula- 
hon with the malar bone; externally it is separated from the posterior 
surface by a rounded border on which begins the infra-orbital canal by a 
notch ; this border forming, in the articulated skull, the lower margin of 
a fissure, the spheno-maxillary. 
The internal or nasal surface aids in forming the outer wall of the nose, 
and presents a large irregular aperture leading into the antrum of High- 
this aperture is much reduced by articulations with neighboring 
fi°nes, palate, ethmoid, lachrymal and inferior turbinated. The antrum 
ls indistinctly triangular; in it are seen numerous vertical grooves and 
°n Us floor several conical projections which mark the position of molar 
foeth. In front of the opening into the antrum is a deep vertical groove, 
sulcus lachrymalis. This face is limited above by the nasal process, 
ln front, and behind this by a rough cellular edge for articulation with 
the lachrymal and ethmoid bones; inferiorly is the horizontal palate pro- 
cess, which may be said to divide it into two portions, the part below 
terminating in the alveolar process and the part above forming the in- 
ferior meatus of the nose. The posterior border is rough for articula- 
tion with the palate bone. The anterior edge is sharp and concave and 
forms the margin of the anterior nares. 
The four processes are nasal, malar, palate and alveolar. The nasal 
Process is a long, thin, triangular projection forming a part of the wall 
°f the nose and presenting three borders and two surfaces. 54 
Notes on Anatomy. 
The anterior border is convex, thin and serrated for articulation with 
the nasal bone. 
The posterior border is thick and grooved; the posterior margin of the 
process is rough for articulation with the lachrymal bone ; the anterior 
margin is rounded, continued into the margin of the orbit, and presents 
below a small tubercle. This groove, in the articulated skull, is formed 
into a canal for lodging the nasal duct, and is nearly vertical, being 
slightly oblique backward and outward. The upper border is blunt and 
serrated for articulation with the frontal bone, its internal angular pro- 
cess. 
The external face is concave and marked by small foramina. 
The internal face is crossed from behind forward by two rough ridges, 
crista turbinalis inferior and superior, the former articulating with the 
inferior turbinated and the latter with the ethmoid. Above the superior 
turbinated crest the surface is rough for articulation with the ethmoid; 
between the two crests it is smooth and concave, entering into the middle 
meatus of the nose. 
The malar process forms the upper part of the boundary between the 
anterior and posterior faces. It is concave both in front and behind, tri- 
angular in outline and its summit is rough for articulation with the malar 
bone. 
The palate process projects inward from the lower part of the inter- 
nal surface, forming a portion of the floor of the nose and the roof of the 
mouth. It does not extend as far back as the body of the bone, but may 
be said to be deficient behind. Its upper surface is transversely concave 
and smooth. In front is a foramen which leads into the anterior palatine 
canal, which appears on the inner border of the process as a groove. 
Its lower surface is also concave, but rough, marked by numerous shal- 
low depressions and by a groove externally, which runs from behind for- 
ward. The inner border is rough, to articulate with its fellow on the op- 
posite side; it is thicker anteriorly than posteriorly, and its upper edge is 
raised into a ridge, or crest, which is slightly everted, so as to produce, 
when the bone is articulated, a narrow groove, for the reception of the 
vomer. Towards the front the inner border, in its lower part, pre- 
sents a groove, which sinks into the bone above to communicate with a 
foramen on the upper surface, the anterior palatine. In front the inner 
border terminates in a slender, pointed process, which, united with a 
similar one on the opposite bone, forms the anterior nasal spine. 
The anterior border of the process is the thin concave margin of the 
nose, the nasal notch. Osteology. 
55 
The posterior border is straight and serrated for articulation with the 
horizontal plate of the palate bone. 
The alveolar process projects downwards from the lower, outer part of 
the bone, and forms about a fourth of the circumference of a circle. It 
18 marked by sockets for eight teeth, with intervening septa. 
SUMMARY. 
Body and four processes. 
Anterior Face—Concave; canine fossa ; canine ridge ; incisive fossa ; 
mfra-orbital foramen. 
Body—Quadrilateral and hollow, antrum of Highmore 
Posterior Face—Tuberosity; rough oval surface; palatine groove. 
Superior Face—Triangular, flat, smooth, sloping; groove. 
Internal Face—Opening into antrum, which is triangular, has vertical 
grooves and projections for roots of molar teeth; sulcus lachrymalis. 
Nasal Process—Long, thin; anterior border convex; posterior, deeply 
grooved. Outer face concave; inner two transverse ridges; crista turbi- 
nalis inferior and superior; between them a concavity. Upper extremity 
blunt and serrated. 
Malar Process—Triangular, short, large and rough. 
Palate Process—Projects inward from inner surface; defective pos- 
teriorly; upper face concave and smooth; lower face concave and rough, 
with antero-posterior groove. Inner border rough; crest: thickest in 
front; grooved; nasal spine and notch. 
Alveolar Process—Projects downwards; forms one-fourth of circle 
sockets for teeth. 
Palate Bone. 
The palate bone enters into the formation of the orbits, the nasal fossae 
and the roof of the mouth. It is divided into horizontal and vertical, 
°r perpendicular portions, or plates. 
The horizontal portion projects inward, at about a right angle, from 
the lower limit of the vertical plate, and presents two surfaces and three 
borders. The superior or nasal face is smooth and concave trans- 
versely, forming the back part of the floor of the nose. The inferior 
face is also slightly concave transversely and rough, forming the poste- 
rior part of the hard palate. A transverse ridge crosses it posteriorly 
The anterior border is serrated for articulation with the palate process 
of the superior maxillary. 
The posterior border is smooth, concave and free, having its inner ex- 
tremity prolonged backwards by a slender, sharp process, which with a 56 
Notes on Anatomy. 
similar projection on the opposite bone, forms the posterior nasal, or 
palate spine. The internal border is thick, rough and serrated for articu- 
lation with its fellow; the upper edge of this border is raised and pro- 
duces, when articulated, a slight groove for the reception of the vomer. 
The vertical plate is irregularly quadrangular and presents two faces, 
internal and external, and three borders, superior, anterior and posterior. 
The internal surface presents two transverse ridges, the superior and in- 
ferior turbinated crests; the inferior to articulate with the inferior turbi- 
nated bone, and the superior with the middle turbinated bone of the 
ethmoid. This surface, below the inferior turbinated crest, is concave 
and forms the outer boundary of the inferior meatus of the nose; the 
surface between the two crests is also concave, and forms a part of the 
middle meatus; above the superior crest is a narrow groove. 
The external surface is, to a great extent, rough for articulation with 
the internal face of the superior maxilla; but at its upper, back part there 
is a smooth portion, which forms a part of the spheno-maxillary fossa. 
At the posterior part of this face is a vertical groove, converted into the 
posterior palatine canal by articulation with the tuberosity of the superior 
maxilla. 
The superior border presents two processes, separated by a deep 
notch. The notch is called spheno-palatine, and is converted into a fora- 
men of that name by the articulation of the sphenoid bone. The ante- 
rior process is known as the orbital; the posterior as the sphenoidal. 
The orbital process inclines outward as it ascends, is hollow and higher 
than the sphenoidal, being perched upon a thin plate of bone, its neck. 
It presents five faces—anterior, posterior, internal, external and supe- 
rior—the first three being articular, the others non-articular. 
The anterior face articulates with the orbital surface of the superior 
maxillary. 
The posterior face articulates with the sphenoid bone. 
The internal face articulates with the ethmoid bone and usually pre- 
sents the opening into the cellular cavity in the process; but this is some- 
times on the posterior face. 
The external face forms a part of the inner wall of the spheno-maxil- 
lary fossa. 
The superior face forms the back part of the floor of the orbit. 
The sphenoidal process is a thin plate of bone, inclining inward as it 
ascends, and presents three faces—superior, external and internal—and 
two borders—anterior and posterior. 
The superior face articulates with the sphenoid bone and presents a 
groove, converted, by articulation, into the pterygo-palatine canal. Osteology. 
57 
The external face partly enters into the formation of the spheno-max- 
hlary fossa, and partly articulates with the pterygoid process of the sphe- 
noid. 
The internal face is free and forms part of the outer wall of the nasal 
fossa. 
The anterior border of the process is the posterior boundary of the 
spheno-palatine notch. 
The posterior border of the process articulates with the pterygoid 
Process of the sphenoid bone. 
The anterior border of the perpendicular plate is irregular, articulates 
With the superior maxillary bone and presents, at the intersection of the 
mferior turbinated crest, a thin process, the maxillary, which aids in 
closing the opening into the antrum maxillare. 
The posterior border of the perpendicular plate is grooved and articu- 
lates with the pterygoid process of the sphenoid. At its lower part is a 
Process, the pterygoid process, or tuberosity of the palate bone. It is 
triangular, is directed downward and backward and outward, and fits into 
the interval between the two plates of the pterygoid process of the sphenoid, 
descending the middle of the tuberosity, posteriorly, is a smooth groove, 
which, when the bone is articulated, forms part of the pterygoid fossa; on 
each side of this groove is a rough groove, which articulates with the corre- 
sponding plate of the pterygoid process of the sphenoid. Externally 
the tuberosity is rough and articulates with the superior maxilla. The 
°penings of numerous canals, the accessory posterior palatine canals, 
are seen on the tuberosity, and it is perforated vertically through its base 
hy the posterior palatine canal. 
SUMMARY. 
Horizontal and vertical portions. 
Horizontal portion—Upper or nasal surface, concave and smooth; 
lower, roof of mouth; concave, rough, transverse ridge, externally a 
groove. Anterior border serrated and articular. Internal border also 
rough and articular. Posterior border, smoothly concave and free; pos- 
terior nasal or palatine spine. 
Vertical Portion—Inner Surface; superior and inferior turbinated crests, 
concave space between. 
Outer Surface—at back part, vertical groove, post-palatine canal. 
Upper Border; orbital and sphenoidal processes, with spheno-palatine 
n°tch between. 
Orbital Process—Anterior face articulates with superior maxillary. 
Posterior face articulates with sphenoid. 58 
Notes on Anatomy. 
Internal face articulates with ethmoid. 
Superior face free and orbital. 
Outer face enters into spheno-maxillary fossa. 
Sphenoidal Process—Superior face articulates with sphenoid. 
Inner face free and nasal. 
Outer face partly enters spheno-maxillary fossa and partly articular 
for pterygoid process. 
Anterior border of vertical plate, irregular, articular for superior max- 
illary, maxillary process. 
Posterior border of vertical plate, grooved, articular for pterygoid pro- 
cess, terminates below in tuberosity. 
Tuberosity, triangular, projects downward, backward and outward, 
behind has shallow smooth groove, with rough groove on each side; ex- 
ternally, rough. 
Inferior Maxillary Bone. 
The inferior maxilla, or lower jaw bone, is a single bone forming the 
lower jaw. It consists of a horizontal portion, the body and a vertical 
portion, the ramus, on each side. 
The body is semicircular of a horse shoe shape, and presents an ex- 
ternal and an internal surface and two borders. 
The external surface is convex from side to side, concave from above 
downward. In front, on the middle line, is a vertical ridge, the symphysis 
menti or crista mentalis; this spreads out as it descends, forming a tri- 
angular projection, the mental process, which produces the prominence 
of the chin. External to the symphysis is a depression, the incisive fossa, 
and still farther out is a foramen, the mental. Extending upward and 
backward from the mental foramen is an indistinct ridge terminating in 
the anterior border of the ramus, and called the external oblique ridge. 
The posterior surface is concave transversely, and presents in front 
four projections called spinae mentales, or genial tubercles, superior and 
inferior; they are situated two on each side of the middle line, one above 
the other, but frequently coalescing to form one. External to the genial 
tubercles is a slight depression, for the sublingual gland; and below this 
another small depression, the digastric fossa. Extending upward and 
backward from the digastric fossa is a ridge, the internal oblique, or 
mylo-hyoid ridge, below the posterior half of which is a depression, the 
sub-maxillary fossa. 
The upper border is the alveolar process and presents the sockets for 
sixteen teeth with intervening septa. The lower, or basilar border is 
rounded, smooth and generally protuberant. It may be marked about 
where it joins the ramus by a slight groove for the facial artery. Osteology. 
59 
The ramus is a quadrilateral plate which projects more or less obliquely 
upward from each posterior extremity of the body. It is divided into 
two surfaces and four borders. 
The external face is rough and ridged for muscular attachment. 
The internal face presents a large foramen, the inferior dental, bounded 
below by a sharp lip of bone; extending downward and forward from 
the foramen is a groove, the mylo-hyoidean. The foramen is the opening 
°f the inferior dental canal, which extends downward and forward through 
the ramus and then forward through the body, beneath the alveoli, with 
each of which it communicates; from near the symphysis it recedes to 
the mental foramen. 
The anterior border is grooved, the outer lip of the groove being con- 
tinuous with the external oblique ridge. 
The posterior border is more or less oblique and rounded. 
The lower border, continuous with the basilar border of the body, is 
straight. At the iunction of the lower and posterior border is situated 
the angle of the lower jaw, which is rough and everted. 
The superior border presents two projections, separated by a deep 
uotch called the sigmoid notch. The projection in front of the notch is 
the coronoid process; that behind, the condyle. 
The coronoid process is thin and triangular. 
The condyle of the lower jaw consists of a convex, oval, articular sur- 
face, mounted upon a constricted portion called the neck. The long di- 
ameter of the condyle is oblique, extending from without inward and 
backward. The articular surface, which plays in the glenoid fossa of the 
temporal bone, extends farther down posteriorly than anteriorly. The 
neck of the condyle is constricted antero-posteriorly, is buttressed by 
fudges and marked externally by a small tubercle, internally by a depres- 
sion. 
As life advances from the adult period, the obliquity with which the 
ramus ascends increases, so that in extreme old age it almost prolongs 
the direction of the body. In early life the angle between the ramus and 
the body is also great, but it decreases gradually up to middle life, when 
tt is nearly a right angle. When the teeth have been for sometime lost 
the alveolar process wastes and finally disappears, so that the upper bor- 
der of the body may correspond with the external oblique ridge. 
SUMMARY. 
Horizontal portion, or body and vertical portion, or rami. 
Body—Anterior surface; convex transversely, concave vertically; crista 60 
Notes on Anatomy. 
mentalis; mental process, incisive fossa, mental foramen, external oblique 
ridge. 
Posterior Surface—concave transversley, superior and inferior spinse 
mentales or genial tubercles, sublingual fossa, digastric fossa, internal 
oblique or mylo-hyoidean ridge, sub-maxillary fossa. 
Superior Border—alveolar, sockets for sixteen teeth with septa be- 
tween. 
Inferior Border—basilar, rounded, protuberant, groove for facial artery. 
Ramus—Outer Surface—ridged. 
Inner Surface—inferior dental foramen of inferior dental canal, which 
traverses body and ramus, and terminates at mental foramen. Sharp lip 
and spine below foramen, mylo-hyoidean groove. 
Anterior Border—grooved. 
Posterior Border—more or less oblique. 
Inferior Border—straight; at junction with posterior border is the angle 
of the inferior maxilla, which is rough and everted. 
Superior Border—coronoid process, sigmoid notch, condyle. 
Condyle—articular, convex, oval, long diameter from without inward 
and backward; neck is thin and flattened from before backward, and has 
fossa internally. 
The Articulated Skull. 
The articulated skull is produced by the union of the bones of the cra- 
nium and the bones of the face. A description of the articulations, 
known as sutures, will be found under the head of articulations in gen- 
eral. 
The skull is divisible into five regions: superior, inferior, anterior and 
two lateral. 
Superior Region. 
The superior region, or vertex, is bounded in front by the frontal emi- 
nences, on each side by the temporal ridge, and behind by the posterior 
occipital protuberance and the superior curved lines of the occipital bone. 
It is formed by part of the frontal bone, most of the parietal bones and a 
part of the occipital bone. It is divided into a superior and an inferior 
aspect. 
The superior surface is seen to be crossed transversely by the coronal 
suture, extending backward from the centre of which is the sagittal su- 
ture, which terminates posteriorly in the lambdoid suture. The parietal 
foramen may be seen on each side of the sagittal suture near its posterior 
extremity. On each side is seen the parietal eminence. This surface is 
markedly convex. Osteology. 
61 
The inferior, or cerebral surface, is concave, and presents the following 
aPpearances: on the frontal bone, in the middle line, is seen the indistinct 
commencement of a groove, for the superior longitudinal sinus, which 
Passes backward, growing broader and more distinct as it travels, first 
along the line of union of the parietal bones and then down the superior 
limb of the occipital cross to terminate at the anterior occipital protuber- 
ance; along the edges of this groove are seen several pits for lodging the 
Pacchionian bodies, and external to these the digital pits for the convo- 
lutions of the brain; numerous arborescent arterial furrows are also seen. 
The lateral region is subdivided into four portions—mastoid, tempo- 
ral, zygomatic and spheno-maxillary. 
Lateral Region 
Mastoid Portion. 
The mastoid portion of the lateral region extends backward from the 
cnfinentia articularis, and in it are seen the following appearances: the 
uiastoid foramen and process; the external auditory meatus; the auditory 
Process, the glenoid fossa, which is bounded above by the posterior root 
°f the zygoma, behind by the middle root and vaginal process, and in 
front by the anterior root of the zygoma. It is crossed transversely by 
fissure of Glaser, the surface in front of the fissure being articular 
and that behind, rough; where the roots of the zygoma meet is the tu- 
bercle. 
The temporal portion of the lateral region is also called the temporal 
l°ssa. Its upper and posterior limit is the temporal ridge; this ridge 
commences at the external angular process of the frontal bone and curv- 
lng upwards and backwards, leaves the frontal and passing across the 
Parietal bone, arches downward over the squamous portion of the tem- 
poral bone and terminates in the posterior root of the zygoma. In front 
°f the temporal fossa is the external angular process of the frontal bone 
and the malar bone. Below, it terminates at the zygoma without and the 
pterygoid ridge within. Its constituents are furnished by the frontal 
bone, the malar bone, the greater wing of the sphenoid the parietal bone 
and the squamous portion of the temporal bone. 
Temporal Portion. 
The zygomatic portion of the lateral region is situated below the tem- 
poral portion and is bounded above by the lower surface of the greater 
Zygomatic Portion. 62 
Notes on Anatomy. 
wing of the sphenoid, the pterygoid ridge and the squamous portion of 
the temporal bone; in front, by the posterior surface of the superior max- 
illa and by the malar; internally, by the external pterygoid plate and 
pterygo-maxillary fissure; externally, by the zygoma and the ramus of 
the inferior maxilla. In this region are seen two fissures, one horizontal, 
the spheno-maxillary, and one vertical, the pterygo-maxillary, the one 
being at a right angle to the other. The spheno-maxillary fissure is seen 
by looking into the orbit; it is situated at the lower part of its outer wall 
posteriorly, between the greater wing of the sphenoid above and the or- 
bital plate of the superior maxilla below, terminating, frequently, in the 
malar bone anteriorly; the posterior termination is at the point where the 
pterygo-maxillary fissure begins, which descends between the tuberosity 
of the superior maxillary in front and the pterygoid process behind. 
Spheno-Maxillary Fossa. 
At the point of junction of the two fissures is a small fossa, the size of 
the end of the little finger, called the spheno-maxillary fossa; it is thus 
formed: above is the flat surface just at the base of the pterygoid process 
anteriorly; behind is the pterygoid process; in front is the superior max- 
illa; internally is the perpendicular plate of the palate bone. There are 
five foramina found in this fossa. Three of them are found on the upper 
posterior wall, i. e., on the flat surface at the base of the pterygoid pro- 
cess; they are—ist, foramen rotundum ; 2d, pterygoid, or Vidian; 3d, 
pterygo-palatine; on the inner wall is seen the 4th, spheno-palatine; and 
sth, inferiorly, is seen the opening into the posterior palatine canal, with 
accessory posterior palatine canals. 
Taking the lateral region of the skull as a whole, it may be seen, from 
the foregoing description, that it is triangular in outline and is bounded 
as follows; the base is represented by the sweep of the temporal ridge; 
the apex is at the angle of the inferior maxilla; the sides may be repre- 
sented by two lines, meeting at the angle of the inferior maxilla, the one 
drawn from the external angle of the frontal bone and the other from the 
mastoid process. The bones entering into its formation are: the mastoid 
and squamous, and the base of the petrous; portions of the temporal 
bone; part of the frontal bone; part of the greater wing of the sphe- 
noid, part of the parietal, part of the malar, and the constituents of the 
spheno-maxillary fossa, as given above. 
The inferior region, or base of the skull, presents two surfaces—supe- 
rior, or cerebral, and inferior, or basilar. 
Inferior Region. Osteology. 
63 
The superior surface of the base of the skull is very uneven, supports 
the brain and is made of three depressions, lying one behind the other, 
and called anterior, middle and posterior fossae. 
The anterior fossa extends from the front wall of the cranium to the 
Posterior border of the lesser wing of the sphenoid bone on each side 
and the olivary ridge in the centre. It is made up of the following bones: 
the orbital plates of the frontal; the cribriform plate of the ethmoid; the 
lesser wings and anterior portion of the body of the sphenoid. On 
either side the surface is somewhat convex from the bulging of the orbital 
Plates; in the centre is the sunken surface of the cribriform plate, having 
ln its centre the crista Galli, and on either side of this three rows of small 
foramina; in front of the crista Galli is the foramen coecum and, along- 
Slde its base, the nasal groove and slit. At the posterior termination of 
the fossa, in the centre, is the olivary ridge, terminating laterally, per- 
haps, in the middle clinoid processes, overhanging which are the ante- 
nor clinoid processes ; in front of the olivary ridge are the optic groove 
and foramina. 
The middle fossa is bounded in front by the posterior borders of the 
lesser wings of the sphenoid bone, laterally, and the olivary ridge in the 
centre; behind, by the upper border of the petrous portion of the tem- 
poral bone, on each side, and, in the centre, by the basilar suture. It is 
formed by the upper surface of the body and greater wings of the sphe- 
noid, part of the squamous and the anterior surface of the petrous por- 
bon of the temporal bone. In the centre is seen the sella Turcica, on 
each side of which is a smooth, broad groove, the carotid or cavernous; 
more externally is an antero-posterior row of foramina, foramen lace- 
rurn anterius, (sphenoidal fissure), opening forward; foramen rotundum, 
also opening forward; foramen ovale, opening downward ; foramen spi- 
nosum, opening downward; foramen lacerum medium. On the anterior 
face of the petrous portion of the temporal bone are seen the following 
Points, from within outward: the digital pit, the groove leading to the 
hiatus Fallopii, the petrosal groove, the bulge of the superior semicircu- 
lar canal, the depression corresponding to the tympanum. 
The posterior fossa is bounded in front by the upper border of the 
Petrous portion of the temporal bone, on each side, and in the centre by 
the basilar suture; posteriorly it is bounded by the horizontal limbs of 
the occipital cross and the anterior occipital protuberance. It is formed 
by part of the occipital, part of the body of the sphenoid, part of the 
parietal and the mastoid and posterior face of the petrous portions of 
the temporal. In the centre in front is the dorsum ephippii; behind this 
18 the concave superior face of the basilar process ; behind this is the 64 
Notes on Anatomy. 
foramen magnum, on either side of which are the anterior condyloid for- 
amina and the tubercles for the check ligament; behind the foramen 
magnum is the vertical limb of the occipital cross. On the posterior 
surface of the petrous portion of the temporal are seen the internal au- 
ditory meatus and the opening of the aqueduct of the vestibule. Just 
behind the petrous bone, and between its posterior border and the occi- 
pital bone, is the foramen lacrium posterius, or jugular foramen, which 
is usually partially subdivided by a spine projecting from the posterior 
border of the petrous bone. Arching inward to the jugular foramen is a 
broad, shallow groove for the lateral sinus; this groove begins at the 
anterior occipital protuberance and passes outward on each side, along 
the horizontal limb of the occipital cross, then curves downward over 
the posterior inferior angle of the parietal bone, and the mastoid portion 
of the temporal, and, regaining the occipital, reaches the jugular foramen. 
Basilar Surface. 
The basilar surface of the inferior region of the skull is formed by the 
palate processes of the superior maxillary and palate bones, the vomer, 
the pterygoid processes, body and greater wings of the sphenoid, the 
squamous, mastoid and petrous portions of the temporal and the occipi- 
tal. It is bounded in front by the alveolar processes of the superior 
maxillary; behind, by the superior curved lines of the occipital and the 
posterior occipital protuberance; laterally by the lower border of the 
malar, the zygoma, and the mastoid process of the temporal. It pre- 
sents in front the hard palate, which, when the skull is inverted, for study, 
is considerably raised above the rest of the surface, and is bounded in 
front and laterally by the semicircular sweep of the alveolar processes. 
It is marked by crucial sutures, one extending along the middle line, be- 
tween the palate processes of the superior maxillary bones and the hori- 
zontal plates of the palate bones; the other being transverse and unit- 
ing the palate processes of the superior maxillary and the horizontal 
plates of the palate bones. Near the front of the median suture, and 
just behind the incisor teeth, is a foramen, the anterior palatine, which 
passes between the nose and the mouth, and opens above by two aper- 
tures, one into each nasal fossa. On each side, near the rear of the pal- 
ate, and just within the last molar tooth, is another foramen, the poste- 
rior palatine; running inward from this is a transverse ridge, and behind 
this is the free, concave, posterior border of the hard palate, which, in the 
centre, is prolonged backward into the palate, or posterior nasal spine; 
running forward from the posterior palatine foramen is a groove leading 
towards the anterior palatine foramen. Behind the hard palate is the Osteology. 
65 
basilar process of the occipital bone, with its pharyngeal spine; behind 
this is the foramen magnum, on either side of which is the occipital con- 
dyle, extending out from which is the transverse ridge; in front of the 
condyle is the anterior condyloid foramen and, perhaps, the posterior be- 
hind it. Behind the foramen magnum is the occipital crest, leading up 
to the posterior occipital protuberance; diverging from about the centre 
°f the crest are the inferior curved lines. 
Returning to the hard palate, we see above it the posterior termination 
°f the two nostrils, called the posterior nares; they are separated by the 
Posterior concave border of the vomer and bounded, each, externally by 
the internal pterygoid plate, terminated below by its hamular process, 
having at its base the scaphoid fossa, and, between itself and the exter- 
nal plate, the pterygoid fossa. Near the base of the external pterygoid 
Plate, a little behind and external, is seen the foramen ovale, and behind 
this the foramen spinosum; external, and posterior, to which are seen, in 
the receding angle between the squamous and petrous portions of the 
temporal bone, the two openings for the Eustachian tube and the tensor 
tympani muscle, separated by the processus cochleariformis. Near the 
base of the internal pterygoid plate is an irregular opening called the 
toramen lacerum medium, which is situated between the greater wing of 
the sphenoid, in front, the apex of the petrous bone, behind, and the body 
°f the sphenoid and basilar process of the occipital, internally ; on its an- 
terior wall is the opening of the Vidian canal. Extending backward and 
°utward is the inferior surface of the petrous bone, which presents the 
following points, from within outward; the rough surface, the carotid 
aPerture, behind which is the jugular foramen, or the foramen lacerum 
Posterius, situated between the posterior border of the petrous portion of 
the temporal and the jugular fossa of the occipital; continuing outward 
from the carotid aperture are the vaginal process, the stylo-mastoid fora- 
men, the auricular fissure, the occipital groove and the digastric fossa. 
Anterior Region, or Face. 
The anterior region of the skull, or the face, is bounded above by the 
frontal eminences, below it is terminated by the mental process and basi- 
lar border of the inferior maxilla; laterally, it is limited by the malar bone. 
is oval in outline, with its long diameter vertical and its broad end 
above. From above downward the appearances are as follows: below 
the frontal eminences are two transverse depressions; below these the 
superciliary ridges separated by the nasal tuberosity; supra-orbital 
ndges ; supra-orbital notches or foramina; the bridge of the nose; the 
orbits; the anterior nares; anterior nasal spine; nasal notches, external 66 
Notes on Anatomy. 
to each of which is the canine fossa, above which are the infra-orbital 
foramen and lower margin of the orbit; just below each nasal notch is the 
incisive fossa, external to which is the canine ridge; bounding the upper 
jaw, below, is the alveolar process of each side, with its teeth, and below 
the alveolar process and teeth of the inferior maxilla ; next come the 
appearances met with on the front of the body of the inferior maxilla; in 
the centre the crest, terminating below in the mental process, on each 
side of it the incisive fossa, the mental foramen and the external oblique 
ridge. The bones that form the face, including the orbits and nasal 
fossae, are three of the cranial bones, frontal, ethmoid and sphenoid, and 
all the facial bones. 
The Orbits. 
The orbits are two conical cavities, or excavations, situated on the up- 
per part of the face and separated by the bridge of the nose and the 
ethmoid bone. Each orbit is conical in shape, its base being forward 
and its apex backward and inward, so that the long axis is oblique, and 
if the two were prolonged backward they would cross over the sella Tur- 
cica. The wall of the orbit is slightly flattened above, below' and late- 
rally, and is thus formed: the upper wall, or roof, is contributed princi- 
pally by the orbital plate of the frontal bone, but is completed behind by 
the lesser wing of the sphenoid ; the lower wall, or floor, is formed 
chiefly by the superior maxillary, completed antero externally by the or- 
bital process of the malar and posteriorly by the upper surface of the 
orbital process of the palate bone; the external wall is formed mainly 
by the greater wing of the sphenoid, but is completed anteriorly by the 
orbital process of the malar; the internal wall is formed principally 
by the os planum of the ethmoid, completed in front by the external 
face of the lachrymal and behind by the side of the body of the sphe- 
noid. Nine openings communicate with the orbit, three entering posteri- 
orly, three anteriorly, one externally and two internally. Posteriorly are, 
ist, the optic foramen, found at the apex; 2d, the foramen lacerum anterius, 
at the upper back part of the outer wall; 3d, the spheno-maxillary fis- 
sure, at the lower limit of the outer wall. Anteriorly are, ist, the supra- 
orbital notch, or foramen, at the inner third of the supra-orbital ridge; 
2d, the infra-orbital foramen, about the centre of the lower margin; 3d, 
the opening of the nasal duct, at the inner angle, on the lachrymal bone, 
and formed by it and the nasal process of the superior maxillary. Ex- 
ternally, the temporo-malar, are several small foramina, seen on the 
outer wall, which communicate by canals with the anterior face of the 
malar bone and with the temporal fossa. Internally, ist and 2d, anterior Osteology. 
67 
and posterior ethmoidal foramina, situated in the upper part of the late- 
ral mass of the ethmoid, and opening on the inner wall. 
The Nasal Fossse. 
The nasal fossae are two irregular cavities situated in the face and ex- 
tending from the anterior to the posterior nares. The septum between 
ttie two is formed, above, by the perpendicular lamella of the ethmoid 
b°ne, in its lower posterior part, by the vomer and the angular interval 
left between the two, in front, is filled in by a triangular plate of fibro- 
cartilage, called the cartilage of the septum. Each fossa presents for 
lamination four walls. The inner wall is formed by the septum. The 
lhe outer wall is formed by the superior maxilla, the inferior turbinated, 
lhe lachrymal, the ethmoid, the palate and the internal pterygoid plate of 
sphenoid. The roof is formed by the nasal, the frontal, the ethmoid 
and the body of the sphenoid. The floor is formed, in front, by the palate 
Process of the superior maxilla and completed behind by the horizontal 
Plate of the palate bone. The outer wall of the nasal fossa is very un- 
even; a considerable bulge inward is produced, throughout its whole 
length, by the inferior turbinated bone, and the space between this bone 
and the floor is called the inferior meatus. Above the inferior is the 
middle turbinated bone, a part of the lateral mass of the ethmoid, and the 
sPace between these two is known as the middle meatus. In the upper 
Part of the inner face of the lateral mass of the ethmoid, is a fissure called 
superior meatus, situated between the superior and middle turbina- 
ted bones of the ethmoid. Opening into each fossa are eight apertures. 
Into the superior meatus there are three openings: ist, the opening of 
the sphenoidal cells; 2d, the opening from the posterior ethmoidal cells; 
3d, the spheno palatine foramen, communicating with the spheno-maxil- 
lary fossa. In the middle meatus there are also three openings: ist, the 
the opening into the antrum-maxillare; 2d, the opening into the antcrior- 
ethnioidal cells; 3d, the opening from the frontal sinus; the last two 
communicating with the upper front part of the meatus through the in- 
fundibulum, Into the inferior meatus there are two openings; ist, the 
nasal duct, on its outer wall, and 2d, the anterior palatine foramen, on 
fhe floor. Just posterior to the outer wall of the inferior meatus is the 
opening of the Eustachian tube. 
Articulations of the Bones of the Skull 
The occipital bone articulates by its two condyles with the Atlas; by 
lt;s superior border with the two parietal bones, forming the lambdoid 
Occipital Bone. 68 
Notes on Anatomy. 
suture; by the outer half of each inferior border with the posterior border 
of the mastoid portion of the temporal bone, and by the inner half with 
the posterior border of the petrous portion; by the basilar process with 
the posterior surface of the body of the sphenoid bone, forming the basi- 
lar suture. 
Parietal Bone. 
The parietal bone articulates by its upper border with its fellow, form- 
ing the sagittal suture; by its lower border with the upper part of the 
semicircular border of the squamous portion of the temporal bone, 
forming the squamous suture; by its posterior border with the upper 
border of the occipital; by its anterior border, with one-half of the semi- 
circular border of the frontal, forming one-half of the coronal suture; by 
its anterior, inferior angle, with the frontal triangle of the sphenoid, i. e., 
the upper border of the outer surface of the greater wing of the sphenoid; 
by its posterior inferior angle, with the upper border of the mastoid por- 
tion of the temporal bone. 
Frontal Bone. 
The frontal bone articulates by its superior, or semicircular border with 
the anterior border of the two parietal bones; by the posterior border of 
each orbital plate with the lesser wing of the sphenoid; by the triangular 
surface i. e., the sphenoidal triangle of the frontal, at the junction of the 
straight and semicircular borders, with the outer surface of the greater 
wing of the sphenoid ; by the circumference of the ethmoidal fissure with 
the lateral and anterior borders of the cribriform plate of the ethmoid, and 
with the upper surface of the lateral mass of the ethmoid; by the nasal 
notch with the nasal bones and the nasal process of the superior maxill- 
ary ; by the nasal spine with the crest of the nasal bones, in front, and 
with the uppV part of the anterior border of the perpendicular lamella 
of the ethmoid, behind ; by the internal angular process with the lachry- 
mal bone ; by the external angular process with the frontal process of the 
malar bone, and by the part just behind this with the orbital process of 
the malar. 
Temporal Bone. 
Squamous Portion. 
The squamous portion articulates by the upper part of its semicircular 
border with the lower border of the parietal bone; by the front part of 
the same border with the posterior border of the outer surface of the 
greater wing of the sphenoid; by the lower part of the same border with 
the outer part of the posterior border of the upper surface of the greater Osteology. 
69 
Wlng of the sphenoid ; by the anterior part of the glenoid fossa with the 
condyle of the inferior maxilla; by the extremity of the zygomatic pro- 
cess with the zygomatic process of the malar bone. 
Mastoid Portion. 
By its upper border with the posterior inferior angle of the parietal; by 
lts posterior border with the outer half of the lower border of the occipi- 
tal bone. 
Petrous Portion. 
The petrous portion articulates by its posterior border with the inner 
half of the lower border of the occipital bone; by its anterior border with 
the middle part of the posterior border of the upper surface of the greater 
"hog of the sphenoid. 
Sphenoid Bone. 
Body; By the posterior surface of the body with the basilar process of 
the occipital; by the ethmoidal spine with the sphenoidal notch of the 
cribriform plate of the ethmoid; by the crest with the upper part of the 
Posterior border of the perpendicular lamella of the ethmoid ; by the 
surface on each side of the crest with the posterior extremity of the late- 
ral mass of the ethmoid, through the medium of the pyramid of Wistar, 
by which it also articulates with the posterior surface of the orbital and 
uPper surface of the sphenoidal process of the palate bone; by the ros- 
trum and vaginal processes with the upper border of the vomer. 
Greater Wing: By the middle part of the posterior border of its upper 
surface with the anterior border of the petrous bone; by the outer part 
°f the same border with the lower part of the semicircular border of the 
squamous portion of the temporal; by the posterior border of the outer 
face with the anterior part of the semicircular border of the squamous 
Portion of the temporal; by the upper border of the outer face, with the 
anterior inferior angle of the parietal and with the frontal bone ; by the 
anterior border of the outer face with the orbital process of the malar 
b°ne; by the upper border of the orbital face with the straight border of 
tbe frontal bone, i. e. sphenoidal triangle of the frontal; by the outer 
border of the orbital face with the orbital process of the malar; by the 
triangular rough surface between the outer and orbital faces, i. e. the 
frontal triangle, with the triangular surface at the junction of the semi- 
circular and straight borders of the frontal bone, i. e. the sphenoidal tri- 
angle. 
Lesser Wing: By its anterior border the lesser wing articulates with 
the posterior border of the orbital plate of the frontal. 70 
Notes on Anatomy. 
Pterygoid Process: By its anterior border with the posterior border of 
the perpendicular plate of the palate bone; by the triangular interval be- 
tween the lower part of its two plates with the tuberosity of the palate 
bone; by the inner side of its base with the posterior part of the outer 
surface and posterior border of the sphenoidal process of the palate bone. 
Ethmoid Bone. 
Horizontal Plate: By its lateral and anterior borders with the circum- 
ference of the ethmoidal fissure of the frontal; by the sphenoidal notch 
with the ethmoidal spine of the sphenoid. 
Perpendicular Lamella: By the upper part of its posterior border with 
the crest of the sphenoid; by the lower part of its posterior border with 
the upper part of the anterior border of the vomer; by the upper part 
of its anterior border with the nasal spine of the frontal; by the lower 
part of its anterior border with the crest of the nasal bones. 
Lateral Mass : By its upper surface it is continuous with the lower sur- 
face of the horizontal plate; by its posterior extremity with the anterior 
face of the body of the sphenoid bone, through the medium of the pyra- 
mid of Wistar; by its anterior extremity with the inner face of the lach- 
rymal bone and with the inner face of the nasal process of the superior 
maxillary; by the upper border of the os planum with the horizontal 
plate, by the lower border of the os planum with the inner border of 
the orbital face of the superior maxillary bone, and behind that with 
the orbital process of the palate bone; by the posterior border of the 
os planum with the front of the body of the sphenoid; by the ante- 
rior border of the os planum with the posterior border of the lachrymal 
bone; by the part below the os planum with the inner face of the supe- 
rior maxillary bone ; by the unciform process with the ethmoidal process 
of the inferior turbinated bone; by the anterior extremity of the middle 
turbinated bone with the superior turbinated crest of the nasal process of 
the superior maxillary; by the posterior extremity of the middle turbi- 
nated bone with the superior turbinated crest of the vertical plate of the 
palate bone. 
Nasal Bone. 
By its upper border with the nasal notch of the frontal bone; by its outer 
border with the nasal process of the superior maxillary ; by its inner bor- 
der with its fellow; by the crest of the two bones, above, with the nasal 
spine of the frontal; below, with the lower part of the anterior border of 
the perpendicular lamella of the ethmoid. Osteology. 
71 
Superior Maxillary. 
Body: By the lower part of its posterior border with the front of the 
tuberosity of the palate bone; by the internal border of its orbital surface, 
from before backwards, with the lower border of the lachrymal bone, the 
°s planum of the ethmoid and the anterior face of the orbital process of 
the palate bone: Antero-externally the orbital face articulates with the 
lower part of the internal, or posterior border of the orbital process of 
the malar; by its internal face the body articulates, by the part posterior 
to the aperture of the sinus with the anterior border, the maxillary pro- 
cess and most of the outer surface of the vertical plate of the palate; 
above the aperture with the outer surface of the lateral mass of the eth- 
moid, below the os planum; below the aperture with the maxillary pro- 
cess of the inferior turbinated bone; in front of the aperture with the 
Projection on the anterior border of the lachrymal and the lachrymal 
Process of the inferior turbinated ; by the inferior turbinated crest with 
the anterior extremity of the inferior turbinated. 
The superior maxillary bone articulates by its body and processes. 
Malar Process: By the malar process with the maxillary process of the 
Malar. 
Palate Process: By the inner border of the palate process with the 
lnner border of the opposite palate process and with the anterior part of 
the lower border of the Vomer; by its posterior border with the anterior 
border of the horizontal plate of the palate. 
Nasal Process: By its upper border with the nasal notch of the 
frontal; by the inner edge of its posterior border with the inner edge of 
the anterior border of the lachrymal; by the upper part of its internal 
surface with the anterior extremity of the lateral mass of the ethmoid; 
by the superior turbinated crest with the anterior extremity of the middle 
turbinated bone; by its anterior border with the posterior border of the 
uasal bone. 
Palate Bone. 
The palate bone articulates by its two plates. 
The horizontal plate articulates by its inner border with the opposite 
bone and with the posterior part of the lower border of the Vomer; by its 
anterior border with the posterior border of the palate process of the 
superior maxillary. 
The Perpendicular Plate articulates by most of its external surface, its 
anterior border and maxillary process with the inner face of the body of 
the superior maxillary, behind the aperture into the antrum; by its supe- 72 
Notes on Anatomy. 
rior turbinated crest with the posterior extremity of the middle turbinated 
bone; by its inferior turbinated crest with the posterior extremity of the 
inferior turbinated bone; by its posterior border with the anterior border 
of the pterygoid process of the sphenoid; by the anterior face of the 
tuberosity with the lower part of the posterior border of the body of the 
superior maxillary and by its posterior face with the lower part of the 
anterior edge of the pterygoid process of the sphenoid; by the anterior 
face of its orbital process with the posterior part of the internal border 
of the orbital face of the body of the superior maxillary; by its internal 
face with the external surface of the lateral mass of the ethmoid, below 
and behind the os planum; by its posterior face with the front of the 
body of the sphenoid, through the pyramid of Wistar. By the upper 
surface of the sphenoidal process with the lower surface of the vaginal 
process of the sphenoid; by its posterior border and the posterior part 
of its outer face with the inner side of the base of the pterygoid process 
of the sphenoid. 
Vomer. 
The vomer articulates by its borders. 
By the groove on its upper border with the rostrum of the sphenoid; 
by its alae with the opposing faces of the vaginal process and lower sur- 
face of the body of the sphenoid; by its lower border, posteriorly, with 
the crested inner border of the horizontal plate of the palate and anteri- 
orly with the crested inner border of the palate process of the superior 
maxillary; by the upper part of the anterior border with the lower part 
of the posterior border of the perpendicular plate of the ethmoid. 
Inferior Turbinated Bone. 
By its anterior extremity with the inferior turbinated crest of the supe- 
rior maxillary; by its posterior extremity with the inferior turbinated 
crest of the palate; by the lachrymal process with the edges of the lach- 
rymal sulcus of the inner face of the body of the superior maxillary and 
with the projection on the anterior border of the lachrymal; by the 
maxillary process with the lower margin of the aperture of the antrum; 
by the ethmoidal process with the unciform process of the ethmoid. 
Lachrymal Bone. 
The lachrymal bone articulates by its upper border with the internal 
angular process of the frontal; by its posterior border with the anterior 
border of the os planum; by its lower border with the front part of the 
internal border of the orbital plate of the superior maxillary; by the Osteology. 
73 
mner edge of the anterior border with the inner edge of the posterior 
border of the nasal process of the superior maxillary and by the projec- 
tion from the lower end of this border with the edges of the lachrymal 
sulcus on the inner face of the body of the superior maxillary and with 
the lachrymal process of the inferior turbinated bone and by the back 
Part of the internal surface with the anterior extremity of the lateral mass 
°f the ethmoid. 
Malar Bone. 
The malar bone articulates by its processes and by the anterior border 
°f its body, which articulates with the anterior border of the malar pro- 
cess of the superior maxillary. 
By the Frontal Process with the external angular process of the 
Frontal. 
By the Maxillary Process with the malar process of the superior max- 
illary. 
By the Zygomatic Process with the zygomatic process of the temporal 
bone. 
By the Orbital Process; the lower part of its posterior border articu- 
lates with the orbital surface of the superior maxillary, antero-externally; 
the upper part of its posterior border, with the outer border of the orbital 
Plate of the greater wing of the sphenoid. 
Inferior Maxillary Bone. 
The inferior maxillary bone articulates by its condyles with the squa- 
mous part of the glenoid fossa of the temporal bone. 
The Hyoid Bone. 
The hyoid bone, or lingual bone, is placed in the upper, front part of 
the neck at the base of the tongue. It is U shaped and lies horizontally, 
being a symmetrical bone. It is an isolated bone, but is connected by a 
ligamentous cord, on either side, with the styloid process of the tempo- 
mi bone; occasionally this cord becomes ossified and then a complete 
bony arch is formed between the two temporal bones through the hyoid 
bone. It is divided for study into body and four cornua, or projections. 
The body presents two surfaces, two borders and two extremities. The 
auterior surface looks upward and slightly forward and presents four de- 
pressions, separated by a crucial ridge; the confluence of the arms of the 
ndge producing a prominence called the tubercle. The posterior face 
looks downwards and slightly backwards; is concave, both transversely 
aud vertically, presenting a deep concavity. The upper border faces 74 
Notes on Anatomy. 
backwards and is rounded and rough. The lower border faces forward, 
is protuberant and marked by muscular attachment. The extremity is 
oval and roughened by cartilaginous attachment. The greater cornu 
stands backwards from the extremity of the body, on either side, and is 
rounded, grows smaller, but is terminated posteriorly by a nodular en- 
largement. It is slightly flattened vertically. 
The lesser cornu is, until old age, cartilaginous; it is a mere nodule of 
cartilage, hook like and about a quarter of inch long; its direction is up- 
ward, backward and slightly outward and it articulates by a diminutive 
joint at the junction of the body, and greater cornu. It becomes calci- 
fied and its joint obliterated only very late in life. The Ligaments. 
75 
THE LIGAMENTS. 
The study of joints, or articulations, is the study of the relation be- 
tween bones, more particularly of the surfaces of apposition and the 
means by which the bones are held together and at the same time per- 
mitted to move upon one another. In the study of osteology it has been 
seen that the articular surfaces of the different bones present widely vary- 
mg appearances; upon these differences depends the classification of 
loints. In some joints the opposing surfaces present interlocking, tooth- 
like processes, so that the union of the bones results in an immovable 
joint. This form of articulation is called synarthrosis. 
The contiguous surfaces may be roughened, showing the attachment of 
ligamentous fibres passing directly between the bony faces ; or the fibres 
may have been attached through the medium of cartilage, coating the bony 
surfaces. This indicates a joint in which motion is very slight, consisting 
of a twisting of the ligamentous fibres; and the articulation is known as 
amphiarthrosis. 
The bony surfaces, lastly, may be smooth and polished, as a result of 
mutual friction—indicating a freely movable joint of the class, called diar- 
throsis. 
The three classes of joints, then are—ist, Synarthrodial, or immovable 
joints; 2d, Amphiarthrodial, or partially movable; and 3d, Diarthrodial, 
°r freely movable joints. 
Besides the bones, there are other structures which contribute to the 
formation of a joint, as follows: In the Amphiarthrodial and Diarthrodial 
joints, the bones are held together by ligaments. In the Amphiarthrodial 
these not only pass from bone to bone, exterior to the joint, but directly 
between the bones, within the joint, forming what are called interosseous 
ligaments. In the Diarthrodial joints, as a rule, no ligamentous fibres are 
attached to the articulating surfaces of the bones; the ligaments, more or 
less completely surrounding the joint, are attached to both bones beyond 
the articular surfaces. The fibres may entirely surround the joint form- 
lng a capsular ligament, or they may be gathered into separate bundles. 
In the Diarthrodial joints the opposing bony surfaces are coated by 
encrusting, or articular cartilage, which, on its deep face, is firmly at- 
tached to the bone, and presents a perfectly smooth, free surface towards 
the opposing bone. 
In order to lessen friction, and render motion entirely easy, diarthro- 
dial joints possess a secreting, serous-like membrane, called the synovial 
membrane, which secretes a viscid, glairy fluid, called synovia. The syno- 76 
Notes on Anatomy. 
vial membrane, in very early life, is said to be a closed sac, coating the 
entire joint; but soon the portion covering the encrusting cartilage is 
worn away, or becomes inconspicuous. 
If joints are subject to very frequent motion, the effect of friction is 
further guarded against by a plate of fibro-cartilage, called the inter- 
articular cartilage. This is a more or less flat, circular plate of cartilage 
interposed between the encrusting cartilages of the bony surfaces, and 
attached only by its circumference to the ligaments. When this exists 
entire, the joint will have two synovial membranes, but occasionally the 
plate is worn through and then the two membranes communicating, there 
is virtually but one. 
Synarthroidal Joints. 
The immovable joints are almost confined to the bones of the skull, the 
articulations between which are generally called sutures. 
There are several varieties of suture: ist. Dentate, or Serrate, in 
which edges of the bones present interlocking processes, called dentate 
when long and tooth-like, and serrate when short, like the teeth of a saw. 
2d. Suture by Harmony, in which two roughened surfaces come in con- 
tact, as the inner border of the palate processes of the two superior max- 
illary bones. 3d. Schindylesis, where the edge of one bone is received 
in a groove in another, as the articulation between the vomer and the 
sphenoid. 4th. Gomphosis, where a bone is received into a correspond- 
ing cavity in another. This term is applied to the union between the 
teeth and their sockets, and is really no articulation. 
Diarthrodial Joints. 
The diarthrodial joints, in accordance with the varying shape of the 
articular surfaces, are divided into six varities. 
ist. Arthrodia], formed by more or less flat, plane surfaces, so that 
motion is much restricted. 
2d. Hinge or trochlear, or ginglymoid, characterized by the presence 
of a pulley on one of the articular surfaces. In this joint motion can 
occur as a rule, in only two directions. 
3d. Condyloid, in which one element is a condyle, the other a proper 
receiving cavity. These joints are generally capable of very free move- 
ment. 
4th, Saddle shaped, or concave-convex joints, or joints of reciprocal 
reception, where both surfaces are saddle-shaped and mutually interlock. 
The examples of this form of joint are sterno-clavicular, temporo-max- 
illary, trapezio-metacarpal and calcoaneo-cuboid. The Ligaments. 
77 
sth. Pivot, or trochoid joints.—There are only two of these, alto-ax- 
°id and radio-ulnar. They present an osseo-ligamentous ring, in which 
a part of one bone is received; this, in the first example, acting as a pivot 
around which the other bone revolves; while, in the second case, it rotates 
°n its own axis. 
6th. Ball and socket, or enarthrodial joints.—These present a more or 
less spherical head, as one contribution, while a receiving cavity is the 
other. The two important examples of this variety are the shoulder and 
hip, in both of which motion is very free. 
In describing a joint, the following heads have to be considered ; 
Ist. The class and variety. 2d. The bony contributions. 3d. The 
ligaments. 4th. The synovial membrane. sth. The inter-articular car- 
tilage, perhaps. 6th. The motions of which the joint is capable, yth. 
The muscles which strengthen the joint, if any. 
As numerous as the motions seem to be, they can all be referred to 
the following: 
(a) Gliding, which occurs to some extent in all diarthrodial joints, but 
18 peculiarly characteristic of the arthrodial. It consists of the slipping 
°f one, more or less, flat and plane surface on another. 
(J>) Flexion—angular movement of a segment of the body in an antero- 
posterior vertical plane, generally forward, but in some cases backward, 
(c) Extension—the reverse of flexion. 
(d) Abduction—the movement of a segment away from some estab- 
lished mid line, generally that of the body. 
(<?) Adduction—the reverse of abduction. 
(/) Circumduction—the partial performance in rapid and regular suc- 
cession of the four preceding movements, passing, in inward circumduc- 
bon, from flexion to adduction, to extension, to abduction, and again to 
flexion. In outward circumduction the order is reversed. In the per- 
formance of this movement, the moving segment circumscribes a cone- 
shaped space, the apex of which is at the joint and the base at the distal 
extremity of the moving segment. 
(g) Revolution, or false rotation. This occurs at but two joints, the 
atlo-axoid and radio ulnar. In the first case, the atlas revolves around 
the odontoid process as an axis; in the latter the radius rotates around 
lts own axis in the ring formed by the orbicular ligament and the lesser 
sigmoid cavity. 
(70 Rotation, or true rotation. This is almost limited to two joints, 
the shoulder and the hip, and, as it happens, can be defined in the same 
terms for both, viz: movement outward or inward around a line drawn 78 
Notes on Anatomy. 
from the innermost point of the humerus or femur, to the innermost point 
of the inner condyle of either bone. 
6th. A statement of the mechanism of motion—that is, of the changes 
which occur in the relative positions of the articulating surfaces during 
the performance of any given motion. 
7th. The muscles which are in contact with the ligaments of the joint, 
and which may be considered as imparting strength to the articulation. 
Bth. In the important joints, the arteries and nerves distributed to 
them. 
The Articulations of the Vertebral Column. 
The articulations of the spinal column may be divided into those of the 
(Ist) Column in general; (2d; Atlo axoid; (3d) Occipito-atloid; (4th) 
Sacro-vertebral. 
Articulations of the Spine in General 
Each vertebra articulates with the vertebra above and the one below 
by a joint of the diarthrodial class, and arthrodial variety, on each side, 
formed by the inferior and superior articular processes. The ligaments 
are capsular around the articulating surfaces, and those which bind the 
same segments of the different vertebrae together, the common ligaments 
of the spine. 
Articulation of the Articular Processes 
The articulation between contiguous articular processes is a diarthro- 
dial joint of the arthrodial variety, presenting a synovial membrane and 
one ligament, an imperfect capsular ligament. 
The Ligaments of the Spine in General— 
Ligaments of the Bodies. 
The bodies of the vertebrae are connected by means of intervertebral 
disks and anterior and posterior common ligaments. The intervertebral 
disk is found lying between the opposing surfaces of two adjacent ver- 
tebra, firmly adherent to each. In shape it corresponds exactly with the 
bodies between which it lies; in thickness it varies with the different re- 
gions of the spine. Collectively, the disks form about one-fourth the 
length of the column and they are found between all the bodies except 
the first and second, being absent there because the atlas has no body. 
It is formed externally, of concentric laminae of fibrous tissue and fibro- 
cartilage, the centre of the disk being a soft, pulpy mass. The Ligaments. 
79 
The anterior common ligament is found descending along the front of 
the bodies from the axis to the sacrum, widening as it descends. It con- 
sists of several superimposed layers of fibres, the deepest of which are 
short and attached only to adjacent bodies, while the superficial are long 
and extend over four, or five vertebrae. 
The posterior common ligament is found within the spinal canal, at- 
tached to the back of the bodies and extending from axis to sacrum. 
Like the anterior, it consists of several layers of fibres, but, unlike that 
hgament, narrows as it descends ; and, instead of having straight edges, 
ls scalloped, widening over each intervertebral disk and narrowing over 
the bodies. 
Ligaments of the Laminae. 
Two adjacent laminae are held together by yellowish ligamentous fibres, 
called ligamenta subflava, attached to the anterior surface of the lamina 
above and the posterior surface of the one below; this is necessitated by 
the imbricated arrangement of the laminae. 
Ligaments of the Spinous Processes, 
The spinous processes are connected by two ligaments—supra and 
inter-spinous. The supra-spinous is a rounded cord extending from the 
seventh cervical vertebra to the sacrum, and attached to the tips of the 
spinous processes; it is continued upward to the occipital bone by the liga- 
mentum nuchae, which takes its place in the neck. 
The inter-spinous ligament is attached to the adjacent edges of the 
spinous processes, is unimportant and is found only in the dorsal and 
lumbar regions. 
The transverse processes are held together in the lower dorsal and 
lumbar regions only, by thin scattered fibres called inter-transverse liga- 
ments, each extending between adjacent processes. 
Ligaments of the Transverse Processes. 
The Atlo-Axoid Articulation. 
The articulation between the Atlas and the axis consists of a diarthro- 
dial and arthrodial joint on each side, formed by the articular processes, 
as seen between other vertebrae, and of a pivot joint, in front, between the 
Posterior face of the anterior arch of the atlas and the front of the 
odontoid process of the axis. The ligaments of this articulation are six 
m number. 
Ist* Two anterior atlo-axoid, one of which is a cord extending from 80 
Notes on Anatomy, 
the anterior tubercle of the atlas to the front of the base of the odontoid 
process; the other, lying beneath, is a membraneous layer, attached to 
the anterior arch of the atlas and the base of the odontoid process and 
to the body of the axis. 
2d. The posterior-atlo-axoid is a membrane-like ligament attached 
above to the posterior arch of the atlas and below to the lamina of the 
axis. 
3d. The transverse passes horizontally across the foramen in the atlas, 
behind the odontoid process, which it binds to the anterior arch of the 
atlas. As it passes over the odontoid process, it sends a bundle of fibres 
downward, to be attached to the base of the process, and another up- 
ward, to be attached to the basilar process of the occipital, assuming the 
shape of a Greek cross, from which it is called the cruciform ligament. 
4th. Two capsular ligaments connect the articular processes. 
Occipito-Atloid Articulation. 
This is a movable joint of the condyloid variety, the articulating sur- 
faces being the two condyles of the occipital bone, above, and the two su- 
perior articular processes of the atlas, below. The ligaments are: 
Ist. Those between the atlas and occipital bone, seven in number. 
2d. Those between the occipital bone and axis, four in number. 
Ist. The anterior occipito-atloid consists of two parts, a superficial 
rounded cord on the middle line, extending from the basilar process to 
the anterior tubercle of the atlas; and a ligamentous membrane, attached 
above to the anterior margin of the foramen magnum and below to the 
anterior arch of the atlas. 
2d. The posterior occipito-atloid is a broad membrane-like ligament 
passing between the posterior margin of the foramen magnum and the 
posterior arch of the atlas. 
3d. The two capsular ligaments, one on each side, are each attached 
above to the condyle and below around the articulating surface of the 
superior articular process of the atlas. 
4th. The two lateral occipito-atloid, one on each side, extend from the 
transverse process of the atlas to the transverse ridge, process, of the 
occipital bone. 
Occipito-Axoid Ligaments. 
The occipito-axoid appears to be a continuation of the posterior com- 
mon ligament of the spine. It is attached to the posterior surface of 
the body of the axis, and passes up, covering over the odontoid process 
and cruciform ligament, to be attached to the basilar process. The Ligaments. 
81 
The odontoid ligament consists of three parts, having a common at- 
tachment to the extremity of the odontoid process below, while above 
they separate, one being attached to the front margin of the foramen 
Magnum and one to each lateral margin. The three parts are sometimes 
described as three ligaments under the name of check ligaments. 
Sacro-Vertebral Articulation. 
The joint between the sacrum and last lumbar vertebra, is similar to 
that between two vertebrae, the articulating surfaces being the articular 
Processes of the two bones. The ligaments are the same as between any 
two vertebrae, with the addition of two ligaments on each side, the ilio- 
lumbar and lumbo-sacral, which are generally considered among the lig- 
aments of the pelvis. The ilio-lumbar extends from the transverse pro- 
cess of the fifth lumbar vertebra outward to the ilium just above and in 
front of the ear-shaped articular surface. The lumbo-sacral passes from 
the transverse process of the fifth lumbar vertebra downward and out- 
ward to the wing of the sacrum. 
Movements of the Spinal Column. 
Motion at the intervertebral joints is very slight between any two verte- 
brae, but the aggregate is considerable. The movements are flexion, 
extension, right and left lateral movements—right or left abduction, or 
adduction—rotation and circumduction. 
Flexion is the bending of the column forward. The mechanism of this 
Motion is that the inferior articular processes glide upward and backward 
°n the superior, the front of the intervertebral disks being compressed 
and the laminae and spinous processes separating. 
Extension is the reverse of flexion. It is restricted by the anterior 
common ligament and by the spinous processes. Its mechanism is the 
exact reverse of flexion. 
Lateral motion, or abduction, is a bending of the column to one or 
the other side; it is limited by the transverse processes and by the inter- 
vertebral disks. During its performance, the inferior articular processes, 
°n the side towards which motion occurs, glide downward while the 
°Pposite ones pass upward. 
Rotation consists in the movement of the column around its own axis, 
t can occur, of course, to either side. The mechanism is as follows: the 
lr*ferior articular processes, on the side towards which motion occurs, 
m°ve backwards while those opposite move forward, the fibres of the in- 
tervertebral disks being twisted and stretched and the spinous processes 
ni°ving away from the side towards which motion occurs. 82 
Notes on Anatomy. 
Circumduction is the partial performance, in succession, of flexion, ab- 
duction, adduction, extension, so that the head and trunk circumscribe 
the base of a cone-shaped space, the apex of which is in the lumbar 
region where the centre of motion is. In the performance of the various 
movements, the cervical region is the freest and the dorsal the least free. 
The atlo-axoid articulation possesses, in addition to these movements, 
the freedom of revolution, the atlas, conveying the skull with it, moving 
around the odontoid process as on an axis. In this movement the in- 
ferior articular process of the atlas, on the side towards which motion 
occurs, glides backward, and the opposite one forward, on the superior 
articular process of the axis, while the anterior arch of the atlas moves 
on the front of the odontoid process. This movement is restricted 
chiefly by the odontoid ligaments. 
Motion of the occipito-atloid articulation is confined to flexion and ex- 
tension. In flexion the skull goes forward and downward, and the con- 
dyle moves upward and backward in the receiving cavity. The mechan- 
ism of extension is the reverse. 
Costo-Vertebral Articulation. 
The parts of the skeleton which enter into a costo-vertebral articula- 
tion are the posterior extremity of the rib, the body, and transverse pro- 
cess of a dorsal vertebra and the intervertebral disk. 
This articulation is of the diarthrodial class and the arthrodial variety. 
The ligaments which connect the head of the rib with the vertebral col- 
umn are the anterior costo-vertebral, capsular and interarticular. 
The anterior costo-vertebral is attached to the anterior aspect of the 
head of the rib, and radiates in three bundles, the upper of which is at- 
tached to the body of the vertebra above, the lower to the vertebra below, 
and the middle to the intervertebral disk. Owing to the divergence of its 
fibres, this ligament is known as the stellate. The arrangement differs from 
the foregoing description in the first, eleventh and twelfth ribs, where the 
ligament is attached to only one vertebra, as the articular facet is fur- 
nished wholly by one vertebra. 
The capsular ligament consists of a few scatteredjfibres around the ar- 
ticulation. 
The interarticular ligament is attached to the ridge on the head of the 
rib and to the intervertebral disk, thus dividing the joint into two parts, 
each furnished with a separate synovial sac. For the reason above given, 
the first eleventh and twelfth have no interarticular ligament and but one 
synovial sac. 
The articulation between the ribs and the transverse processes, known The Ligaments. 
83 
as the costo-transverse articulation, presents three ligaments—anterior, 
middle and posterior costo-transverse. 
The anterior costo-transverse extends from the neck of the rib to the 
transverse process above; the middle, or interosseous, extends from the 
posterior surface of the neck of the rib directly backward to the trans- 
verse process; the posterior extends from the tubercle of the rib to the 
apex of the transverse process. 
Temporo-Maxillary Articulation. 
This articulation is formed by the condyle of the lower jaw and the 
glenoid cavity of the temporal bone. 
This is a diarthrodial joint of the condyloid variety, and presents four 
ligaments, viz; internal and external lateral, capsular and stylo-maxillary 
and an inter-articular fibro-cartilage, which is sometimes perforated; 
"hen this is the case, there is but one synovial sac, otherwise there are 
two, one between the cartilage and the condyle and the other between 
the cartilage and the glenoid cavity. 
The external lateral ligament is attached to the zygoma above, from its 
tubercle forward, and, passing downward and backward, is attached, be- 
low, to the outer border of the neck of the condyle. 
The internal lateral is attached above to the extremity of the spinous 
Process of the sphenoid bone, and, below, to the shelf of bone forming 
the lower margin of the inferior dental foramen on the inner face of the 
ramus of the lower jaw. 
The capsular ligament consists of thin scattered fibres around the 
joint. 
The stylo-maxillary is, properly, not a ligament of this joint. It ex- 
tends from the styloid process of the temporal bone to the angle and pos- 
terior border of the ramus of the lower jaw. 
The movements at the joint are four, viz: depression, elevation, a late- 
ral and a forward movement. In depression the lower jaw is separated 
from the upper, the lower receding while the upper is almost stationary. 
The mechanism consists in a rolling forward of the condyle on the emi- 
nentia articularis and, when exaggerated, may lead to dislocation. 
Elevation is the reverse of depression. 
In the lateral movement, the lower jaw is twisted to one side, as in 
grinding between the molar teeth. The movement is checked by the 
condyle, of the side towards which motion occurs, coming in contact with 
the inner limit of the glenoid cavity. 84 
Notes on Anatomy. 
Costc-Sternal Articulation. 
The ribs have attached to their anterior extremities the costal carti- 
lages, which prolong the seven true ribs to the side of the sternum, where 
the cartilages are received into the pits found there and are held in place 
by ligamentous fibres passing from them to the sternum in front and be- 
hind. The cartilages of the second and third ribs have also each an in- 
ter-articular ligament. 
The Articulations of the Pelvis. 
The articulations of the pelvis are four, viz; that between the fifth lum- 
bar vertebra and the sacrum, that between the sacrum and coccyx, that 
between the sacrum and the os innominatum of each side and that be- 
tween the two ossa innominata. 
The ligaments of the sacro-vertebral articulation were described with 
those of the spine. The coccyx is held to the sacrum by a small inter- 
vertebral disk and by ligamentous fibres before and behind. 
The ossa innominata are held to the sacrum by an articulation between 
the sacrum and the ilium on each side, and by two ligaments known as 
the greater and lesser sciatic. The sacro-iliac articulation, or symphysis, 
or synchondrosis, is effected by the auricular surface of the sacrum and 
ilium and two ligaments, anterior and posterior sacro-iliac. 
The anterior sacro-iliac consists of a thin plane of fibres passing be- 
tween the front of the sacrum and the ilium. 
The posterior sacro-iliac is a large, strong mass of ligamentous fibres 
which pass from the rough surface behind the auricular surface of the 
ilium to the similar one of the sacrum, filling the deep depression which 
would otherwise exist there. 
The two sacro-sciatic ligaments have common attachment to the edge 
of the coccyx and sacrum and the posterior inferior process of the ilium. 
As the mass passes forward and outward, one part, the lesser sciatic liga- 
ment, is attached to the spine of the ischium, while the rest, as the greater 
sciatic, continues its course to be attached to the tuberosity and ramus 
of the ischium. 
The aperture above the lesser sciatic ligament is known as the great 
sacro-sciatic foramen, and the one between the two ligaments as the les- 
ser sacro-sciatic foramen. 
The articulation between the ossa innominata is found between the two 
pubic bones, and is known as the symphysis pubis. Each bone presents 
an oval articular surface, whose long diameter is downward and back- The Ligaments. 
85 
ward, coated by a thin plate of encrusting cartilage. The two plates are 
Jn contact only at the back part, leaving, in front, a wedge-shaped space 
filled by fibres passing between the two plates. Besides this interarticu- 
lar ligament, there are four others—superior, consisting of fibres passing 
between the two bones above; inferior, fibres passing between the two 
bones below, and filling in the interval between the two rami, so as to 
form a smoothly-curved arch; anterior, fibres passing between the bones 
ln front, and posterior consisting of similar fibres behind. 
Sterno-Clavicular Articulation. 
This is a movable joint of the saddle-shaped variety, formed by the 
upper end of the sternum, the cartilage of the first rib, and the inner ex- 
tremity of the clavicle. 
The cartilage of the first rib has a depression on its upper border, 
which aids in furnishing a receiving cavity for the inner extremity of the 
clavicle. 
The ligaments of this joint are three in number—capsular, costo-cla- 
vicular and inter-clavicular. The capsular ligament is attached to the 
Margin of the articular surface of the sternum, clavicle and cartilage of 
the first rib. It is sometimes spoken of as two ligaments, the anterior 
and posterior sterno-clavicular, continuous above and below. The costo- 
clavicular is attached to the lower surface of the clavicle and passes down- 
ward and inward to seize the upper border of the cartilage of the first 
rib. The inter-clavicular seizes the inner extremity of the clavicle on its 
uPper aspect, where it is continuous with the capsular ligament, and, 
Passing across the top of the sternum, sinking into the semilunar notch, 
seizes the opposite clavicle in the same manner. 
The joint is provided with an inter-articular fibro-cartilage which also 
acts as a ligament. Above, it is attached to the upper part of the articu- 
lar surface of the clavicle; below, at the junction of the sternum with the 
cartilage of the first rib. It is often much worn, especially in laboring 
the degree of attrition being greater on the right side, owing to its 
uiore frequent use. The joint, of course, presents two synovial sacs. 
The movements are slight, but in every direction, upward, downward, 
backward and forward. The inner end of the clavicle moves in an oppo- 
sUe direction to that in which the outer end moves, the cartilage of the first 
db forming a fulcrum. 
This is a movable joint of the arthrodial variety. The articulating 
surfaces are an oval facet on the outer extremity of the clavicle and a 
Scapulo-Clavicular Articulation 86 
Notes on Anatomy, 
corresponding facet on the anterior edge of the acromion process of the 
scapula. It must be observed that the clavicle, in its outward course, 
passes just above the coracoid process of the scapula, and, while it does 
not articulate with it, receives a ligament from it. 
The ligaments are two, capsular and coraco-clavicular. The capsular 
is attached around the articulating surfaces; the coraco-clavicular passes 
from the coracoid process to the under surface of the clavicle. When 
viewed from the front, this ligament presents a quadrilateral outline, and 
is called the trapezoid; from behind, it has a triangular shape, and is 
called conoid. 
The joint is provided with an interarticular fibro-cartilage, which is 
often absent. The movements are slight but varied. 
Ligaments of the Scapula. 
Stretched between different points on the scapula are two ligaments, 
coraco-acromial and transverse. The coraco-acromial, thick and tri- 
angular, is attached by its apex to the tip of the acromion and by its 
base to the coracoid process, serving as a protecting arch for the shoulder 
joint. The transverse ligament passes over the supra-scapular notch, 
from one extremity to the other, converting it into a foramen. 
The Shoulder Joint. 
The shoulder joint, or scapulo-humeral articulation, belongs to the 
diarthrodial class and enarthrodial, or ball and socket, variety. The bony 
surfaces are the upper extremity of the humerus, and the glenoid cavity 
of the scapula. 
The glenoid cavity is surrounded, and slightly deepened, by the glenoid 
ligament, which is a fibro-cartilaginous band, triangular on cross section, 
attached to the circumference of the cavity. Partially continuous with 
the upper part of the glenoid ligament is the tendon of the long head of 
the biceps muscle. 
Holding the bones together is a capsular ligament, attached above to 
the scapula just behind the glenoid ligament, and, below, to the anatomi- 
cal neck of the humerus, from which point it is prolonged over the tube- 
rosities. 
The upper part of the capsular ligament is thickened and is often indi- 
vidualized into a separate ligament, under the name of the coraco-hume- 
ral, extending from the base of the coracoid process to the greater tube- 
rosity of the humerus. The ligament is remarkably long and loose, 
allowing separation of the humerus from the scapula to the extent of The Ligaments. 
87 
nearly an inch, thus endowing the joint with great freedom of movement. 
The synovial membrane of this joint often communicates with a bursa 
beneath the tendon of the subscapularis muscle, and sometimes with one 
beneath the infra-spinatus. 
The following muscles strengthen the various aspects of the joint: 
Above, the supra-spinatus. Behind, the infra-spinatus. In front, ffhe 
subscapularis. Forming a protecting cushion over the joint above, be- 
hind, to the outer side and in front, is the deltoid muscle, which covers 
the insertion of the other muscles and produces the bulge of the shoulder. 
In addition to these muscles, the joint is further protected from violence 
from above by the overhanging arch formed by the acromium and cora- 
coid processes and the coraco-acromial ligament. 
The movements are flexion, extension, abduction, adduction, circum- 
duction and rotation. The mechanism is as follows : 
In flexion, the humerus is carried forward and the head spins on its 
axis. * 
In abduction the humerus is carried outward, the head passing down- 
Ward in the glenoid cavity and pressing against the inferior fibres of the 
Capsular ligament, which may be ruptured by an exaggeration of this 
Movement, producing downward dislocation. 
Extension is the reverse of flexion. 
Adduction is the reverse of this movement. 
Circumduction is a combination of these movements, the head rolling 
around in the glenoid cavity. 
In rotation the humerus revolves around an axis drawn from the centre 
°I the head to the internal condyle—the head moving backward in in- 
ward and forward in outward rotation. 
Radio-Ulnar Articulation. 
The articulation between the two bones of the forearm forms a diar- 
throdial joint of the trochoid or pivot variety. The bones articulate at 
both the upper and lower extremity, being separated by the interosseous 
space throughout the shafts. 
The ligaments holding the bones together are found at their upper and 
lower extremities and between their shafts. Above, the two bones are 
held together by one ligament, the orbicular which forms three-fourths of 
a nng, the other fourth being the lesser sigmoid cavity of the ulna. The 
ligament surrounds the articular rim of the radius and is attached by its 
tw° ends to the extremities of the lesser sigmoid cavity. The lower 
fibres are tightly stretched around the radius just below the head, render- 
lng it very difficult to release that bone from its grasp. 88 
Notes on Anatomy. 
The shafts are connected by two ligaments, the interosseous and the 
oblique. The oblique is a narrow band which passes downward and out- 
ward from the ulna, at the base of the coronoid process, to the radius just 
below' the tuberosity. It is often wanting. 
The interosseous membrane extends from the lower extremities of the 
bones upward about two-thirds the length of the shafts, leaving an inter- 
val above which is the oblique ligament. Its fibres are directed down- 
ward and inward between the inner border of the radius and the outer 
border of the ulna. About the lower third of the forearm, the membrane 
is pierced by a foramen for the anterior interosseous artery. 
At their lower extremities the bones are held together by two ligaments 
and the triangular fibro-cartilage. The two ligaments are an anterior 
and a posterior passing across the two bones. The triangular cartilage 
tips the summit of the capitulum ulnae and excludes it from the wrist 
joint. By its apex it is attached to the pit between the styloid process of 
the ulna and the capitulum ulnae; by its base to the narrow rough surface 
separating the carpal and sigmoid cavities of the radius. 
The movements are two, and in both the radius alone moves. It can 
move forward, pronation, or backward, supination, and in both the hand 
is carried with it. In these movements of rotation, or revolution, the 
radius rotates around an axis represented by an imaginary line drawn 
from the centre of the head of the radius through the centre of the capi- 
tulum ulnae; consequently in performing pronation the sigmoid cavity of 
the radius moves forward on the articular rim of the capitulum ulnae, the 
reverse occurring in supination, while the head of the radius rotates in 
the lesser sigmoid cavity and orbicular ligament. 
The Elbow Joint 
The joint is of the movable class and hinge variety; its bony surfaces 
being furnished by the lower extremity of the humerus on the one hand 
and the upper extremities of the radius and ulna on the other. 
As this is a ginglymoid joint it has no capsular ligament, but the bones 
are held in opposition by ligaments placed in front, behind and at the 
sides. As stated in describing the radio-ulnar articulation, the radius is 
held in the lesser sigmoid cavity by the orbicular ligament; and as revo- 
lution of the radius, which is demanded for free movement of the hand, 
would be impossible if the bone were seized by any ligaments which are 
attached to the humerus, for ligamentous fibres are inelastic, it will be 
found that certain ligaments of this joint, to avoid this interference, are 
attached to the orbicular ligament and that none of them seize the radius. The Ligaments, 
89 
The ligaments of the joint are anterior, posterior, internal and external 
lateral. 
The anterior ligament is attached above to the humerus just above the 
coronoid fossa; below, to the coronoid process and orbicular ligament. 
The posterior ligament is thin and weak. Above, it is attached to the 
humerus just above the olecranoid fossa, below, to the groove on the ole- 
cranon process of the ulna. 
The external lateral descends from the external condyle of the hume 
rUs to seize the orbicular ligament. 
The internal lateral is triangular in shape. It is attached by its apex 
to the internal condyle of the humerus; below, it divides into two fasci- 
culi, one of which is attached to the inner edge of that part of the greater 
Slgmoid cavity found on the olecranon, and the other to that on the coro- 
uoid process. 
The following muscles strengthen the articulation 
In front, the brachialis anticus. 
Behind, the anconeus and triceps. 
Externally, the muscles arising from the external condyle, notedly the 
sUpinator brevis. 
Internally, the muscles arising from the internal condyle. 
The movements are the two characteristic of a hinge joint—flexion 
aud extension. 
The mechanism of flexion is that the greater sigmoid cavity and the 
articular cup of the radius move forward on the trochlea and eminentia 
capuata of the humerus respectively. This movement is checked when 
the apex of the coronoid process impinges on the bottom of the coronoid 
fossa. Extension is the reverse of flexion, and is checked by the beak 
°f the olecranon coming in contact with the bottom of the olecranoid 
fossa. 
The Wrist Joint. 
The wrist joint belongs to the movable class and condyloid variety. 
The condyle is furnished by the upper row of carpal bones, scaphoid, 
semilunar and cuneiform. Its long diameter is transverse. The receiv- 
es cavity is formed by the lower end of the radius and a plate of fibro- 
cartilage lying on the lower extremity of the ulna. This cartilage cuts 
the ulna off from the joint. Its attachment was described with the radio- 
ulnar articulation. 
The ligaments are four, anterior, posterior and two lateral. 
The anterior is attached, above, to the front of the radius and ulna; 
helow, to the front of the bones of the condyle. 90 
Notes on Anatomy. 
The posterior is attached, above, to the back of the radius; below, to 
the back of the bones of the condyle. 
The internal lateral is attached, above, to the styloid process of the 
ulna; below, to the cuneiform and pisiform bones. 
The external lateral is attached, above, to the styloid process of the ra- 
dius; below, to the scaphoid and trapezium. 
The joint is strengthened by no muscles. Many tendons pass over it, 
but they are too slender, lax and free to give support. 
The movements are flexion, extension, abduction, adduction and cir- 
cumduction. 
The mechanism in flexion is as follows: The condyle moves backward 
in its cavity, pressing against the posterior ligament, which may be rup- 
tured by an exaggeration of this movement, producing backward dislo- 
cation of the carpus. This may be produced by a fall on the back of the 
hand when flexed. 
Extension is the reverse of flexion. 
In abduction the hand is moved away from the middle line, the condyle 
moving inward. Adduction is the reverse. 
Circumduction is the combination of these movements. 
Articulation of Carpus and Metacarpus. 
The bones of the carpus, which lie in the same row, are held together 
by ligamentous fibres passing across them in front and behind, palmar and 
dorsal ligaments, and by fibres which seize the adjoining surface of oppos- 
ing bones, called interosseous ligaments. Between the trapezium and tra- 
pezoid there is no interosseous ligament. In the same manner the meta- 
carpal bones of the four fingers are held together at their bases. The 
two rows of carpal bones are held together by ligamentous fibres pass- 
ing from one to the other in front and behind, palmar and dorsal liga- 
ments and by two lateral ligaments, the external passing from the sca- 
phoid to the trapezium, the internal from the cuneiform to the unciform. 
The metacarpal bones of the four fingers are held to the second row 
of carpal bones by fibres in front and behind, palmar and dorsal liga- 
ments, and, in one situation, by interosseous fibres extending from the 
adjacent parts of the os magnum and unciform to the bases of the third 
and fourth metacarpal bones. 
The Trapezio-Metacarpal Joint. 
This articulation belongs to the movable class and saddle-shaped va- 
riety. It is invested by a capsular ligament, and allows the four angu- 
lar movements and their combination, circumduction. The Ligaments. 
91 
The Metacarpo-Phalangeal Articulation. 
The knuckle joint, or metacarpo-phalangeal, is of the movable class 
and condyloid variety. The condyle is furnished by the head of the 
Metacarpal bone and the receiving cavity by the top of the corres- 
ponding phalanx, aided by a plate of cartilage known as the anterior 
I’gament of the joint. 
The ligaments are two lateral, seizing both bones on their lateral as- 
pect just beyond the articular surface. The place of a posterior liga- 
ment is supplied by the extensor tendons of the finger. The anterior 
33 not a ligament in the true sense of the word, being only a mass of 
fibro-cartilaginous material attached to the front edge of the articula- 
tlng surface on the base of the phalanx, and increasing the receiving cav- 
3ty- The movements are the four angular movements and their com- 
bination, circumduction. 
Inter-Phalangeal Articulation 
Ihe articulation between two phalanges is of the movable class and 
binge variety, the head of one phalanx presenting the trochlear and the 
base of the other the corresponding surface. The ligaments are exactly 
Similar to those of the metacarpo-phalangeal articulation but the move- 
ments are only two, flexion and extension. 
The Hip Joint 
1 his joint is of the movable class and ball and socket variety, its bony 
elements being the acetabular cavity of the os innominatum and the upper 
extremity of the femur. 
Surmounting the cavity, in the fresh subject, is a fibro-cartilaginous 
ring called the cotyloid ligament, continued over the- notch in the mar- 
gln- The part stretched over the notch is known as the transverse liga- 
ment. Occupying the depression in the bottom of the cavity is a cushion 
°f fat. 
i he ligaments are the capsular and the ligamentum teres. 
The capsular ligament encloses the joint closely; and, unlike, that at 
*be shoulder is short and keeps the bones in close apposition. It is at- 
tached above to the brim of the acetabulum and below to the neck of the 
femur, extending in front the whole length of the neck, while behind it 
falls short of the posterior intertrochanteric line by one-half inch. The 
uPper part of this ligament is much thicker than the rest, some five 
'■lnies- It receives there the support of what is called the ilio-femoral, or 92 
Notes on Anatomy. 
Y ligament, which is attached above to the anterior inferior spinous pro- 
cess of the ilium and below to the spiral line and front of the great tro- 
chanter of the femur. 
The ligamentum teres is a cord of fibres which, starting from the rough 
depression on the head of the femur, forks and is attached to the sides of 
the notch in the margin of the acetabulum. 
Efficient to the amount of about twenty-six pounds in retaining the 
head of the femur in the acetabulum is atmospheric pressure, the head 
fitting closely from the exact moulding in the socket. 
The muscles which strengthen the joint are as follows; 
Above, the rectus and gluteus minimus. In front, the psoas magnus and 
iliacus internus. Internally, the pectineus and obturator internus. Be- 
hind, the outward rotators of the thigh, obturators, internus and exter- 
nus, pyriformis, the gemelli and the quadratus femoris. Or, beginning 
at random and naming them in the order in which they lie around the 
joint, we have, gluteus minimus, rectus, iliacus internus, psoas magnus, 
pectineus, obturator externus, quadratus femoris, gemellus inferior, ob- 
turator internus, gemellus superior and pyriformis. 
The movements are six in number and are the same as at the shoulder 
joint. The mechanism is also the same. As there dislocation occurs by 
exaggerated abduction, or adduction. 
The Knee Joint. 
The knee 7 the largest and most important joint in the body, belongs to 
the movable class and hinge variety. The bony elements are the lower 
extremity of the femur, above, the upper extremity of the tibia, below, 
and the posterior surface of the patella, in front. 
Lying on each of the glenoid cavities is an imperfect plate of fibro- 
cartilage, called semilunar, external and internal. Each plate is 
thickest at its circumference and slopes off to a thin edge towards the 
centre of the cavity, on which it lies. The internal is oval, its long diam- 
eter antero-posterior and its extremities terminate at the beginning of the 
depressions in front and behind the spine. The external is nearly circu- 
lar and its extremities terminate at the base of the spine in front and be- 
hind, as it were between those of the internal. The circumference of 
each plate is held down on the margin of the glenoid cavity by short 
vertical fibres terming the coronary ligaments right and left. Passing 
across from the most prominent point of one plate to the other, anteriorly, 
is a small cord, called the transverse ligament. 
The ligaments of the joint are anterior, posterior, two crucial and 
three lateral, one internal and two external. The Ligaments. 
93 
The anterior ligament is known as the ligamentum patellae, and extends 
from the lower end of the patella to the anterior tubercle of the tibia, 
*he patella being held to the femur by the attachment of the triceps ex- 
tensor cruris. It is the tendon of insertion of the triceps. 
The posterior ligament covers the whole of the back of the joint, being 
attached, above, to the back of the femur, above the condyles, and below 
to the back of the tibia. Its middle portion is furnished by the tendon 
°f the semi-membranosus. 
The internal lateral ligament is a flattened band of fibres attached to 
the inner tuberosity of the femur, above, and the inner tuberosity of the 
tibia, below. 
The long external lateral ligament extends as a round cord from the 
oxternal tuberosity of the femur to the head of the fibula. The short 
oxternal lateral lies behind the long and has the same attachment below, 
hut above is attached to the groove below the outer tuberosity of the 
femur. It is really the tendon of origin of the popliteus. 
The two crucial ligaments are found within the joint and are distin- 
guished as anterior, or external, and posterior, or internal. The anterior 
18 attached to the tibia in front of its spine and passes upward, outward 
and backward, to seize the inner face of the external condyle. The pos- 
terior is attached to the tibia just behind the spine and passes upward, 
forward and inward to seize the outer face of the internal condyle. The 
two crucial ligaments decussate in the joint—hence the name—and are 
connected where they cross, 
besides the foregoing, there are other, so-called, ligaments, but they are 
n°t true ligaments and have little or no influence in holding the bones to- 
gether. Stretching from the notch between the condyles of the femur to 
a mass of fat which lies behind the ligamentum patellae, there is a fold of 
synovial membrane which is called the ligamentum mucosum. The 
°se edges of this fold are known as the alar ligament. 
T'K . 
jne synovial membrane of the knee is the most extensive in the body. 
18 not only sufficient for the joint itself but it extends on the front of 
fr*e femur from one to two inches above the articular surface. It is wor- 
of note that the synovial sac is not in contact with the posterior face 
° ligamentum patella but is separated from it by a mass of fatty 
tissue. 
Investing all these structures is the continuation of the fascia lata over 
le joint to become the deep fascia of the leg. 
The muscles strengthening the joint are as follows : 
n front triceps extensor cruris. 
enind gastrocnemius, popliteus and semimembraneous. 94 
Notes on Anatomy. 
Externally, the tendon of the biceps flexor cruris. 
The movements are flexion and extension. In flexion the leg is raised 
backward on the thigh, the glenoid cavities of the tibia moving back- 
ward on the condyles. The movement is checked when the leg is in con- 
tact with the back of the thigh. 
Extension is the reverse of flexion. 
It should be observed that in a state of semi-flexion the knee joint is 
capable of slight lateral movement, or rotation, as in eversion or inver- 
sion of the foot. 
The Ankle Joint. 
This joint belongs to the movable class and hinge variety. Its articu- 
lar surfaces are contributed by the lower extremities of the tibia and 
fibula, above, and the upper surface of the astragalus below. 
The ligaments are an anterior and two lateral. The anterior, thin and 
fatty, extends from the front of the tibia to the astragalus in front of the 
pulley. 
The internal lateral, or deltoid, triangular in shape, is attached, above, 
by its apex to the inner malleolus, while, below, its base seizes the sca- 
phoid, astragalus and os calcis. When cut through this ligament is seen 
to consist of two layers and to be very strong. 
The external lateral is really three ligaments, although always described 
as one, consisting of three fasciculi, anterior, middle and posterior. The 
anterior fasciculus extends from the outer malleolus to the astragalus in 
front; the middle passes from the outer malleolus downward to the os 
calcis; and the posterior is attached to the inner aspect of the outer mal- 
leolus, posteriorly, and to the astragalus. 
The place of a posterior ligament is supplied by the tendo Achillis. 
The movements are flexion and extension. In flexion the foot is carried 
forward on the leg, the astragalus moving backward on its receiving sur- 
face. Extension is the reverse. In eversion and inversion there is slight 
lateral movement when the foot is extended. 
The Tibio-Fibular Articulation. 
Extended between the tibia and fibula from just below the knee to the 
ankle joint is a strong ligamentous structure, called the interosseous mem- 
brane, the direction of whose fibres is downward and outward. In the 
upper part of this membrane is the aperture for the transmission of the 
anterior tibial artery. Besides this membrane the tibia and fibula are held 
together at both the upper and lower extremity. 
The upper extremity, or head of the fibula, presents a more or less The Ligaments. 
95 
circular articular facet, which plays on a corresponding facet situated on 
the outer tuberosity of the tibia. The bones are held together here by 
an anterior and a posterior ligament which pass from bone to bone in 
front and behind. The synovial membrane of this joint sometimes com- 
municates with that of the knee. 
The outer aspect of the lower extremity of the tibia presents a rough 
surface, which corresponds to one on the inner face of the lower extrem- 
lly of the fibula, situated just above the articular inner face of the mal- 
leolar process. There is also a very narrow articular surface just below 
the rough surface on the tibia, perhaps. 
The ligaments, like those at the upper extremity, are an anterior and 
f posterior, with the addition of a large mass of interosseous fibres pass- 
lng between the adjacent rough surfaces. 
The Articulations of the Tarsus. 
The articulations of the tarsus consist of the articulation between the 
bones of each row and the union of the two rows. 
Calcaneo-Astragaloid Articulation. 
The two bones of the first row of the tarsus are held together by three 
ligaments, external, posterior and interosseous. 
The external calcaneo-astragaloid extends from the outer side of the 
0s calcis to the outer side of the astragalus. 
The posterior calcaneo-astragaloid passes from the posterior extremity 
°f the astragalus to the contiguous upper aspect of the os calcis and is 
but a continuation of the protective fibres, called the posterior ligament 
of the ankle. 
The interosseous is by far the most important bond of union between the 
two bones. It consists of a large number of fibres, filling the sinus tarsi, 
passing directly and obliquely between the surfaces contributed to 
form that canal. 
The Articulation Between the Bones of the Second Row, 
The bones of the second row are held together by fibres passing across 
e dorsal and plantar faces and by interosseous fibres between opposing 
surfaces. 
The two rows of the tarsus are held together by three sets of ligaments, 
tW° Sets passing from the os calcis to the cuboid and scaphoid, though 
The Articulation Between the two Rows. 96 
Notes on Anatomy 
the latter does not articulate with it, and one set passing between the 
astragalus and scaphoid. 
Calcaneo Cuboid Articulation. 
The ligaments binding the os calcis to the cuboid are four, two dorsal 
and two plantar. 
The superior calcaneo-cuboid is thin and narrow and passes between 
contiguous surfaces of the bones on the dorsum of the foot. 
The internal calcaneo-cuboid, or interosseous, is a thick short band of 
fibres springing from the depression between the os calcis and the astra- 
galus and inserted into the inner side of the cuboid. At its origin it is 
closely blended with the superior calcaneo-scaphoid. 
The long inferior calcaneo-cuboid is attached behind to the lower sur- 
face of the os calcis and in front to the lower surface of the cuboid and 
bases of the adjacent metatarsal bones, second, third and fourth, covering 
in, as it passes forward, the groove in which lies the tendon of the peron- 
eus longus. 
The short inferior calcaneo-cuboid lies deeper than the long and ex- 
tends between the lower front part of the os calcis and the cuboid. 
Calcaneo-Scaphoid Ligaments. 
Connecting the os calcis and scaphoid are two ligaments, superior and 
inferior calcaneo-scaphoid. 
The superior, one arm of the Y ligament, the other arm being furnished 
by the internal calcaneo-cuboid, passes forward and inward from the front 
upper part of the os calcis to the scaphoid. 
The inferior calcaneo-scaphoid is much stronger than the superior and 
passes from the inner front aspect of the os calcis, beneath the head of 
the astragalus, to the lower surface of the scaphoid. 
The Astragalo-Scaphoid Articulation. 
The only ligament connecting the astragalus and the scaphoid is the 
superior astragalo-scaphoid, which is thin and weak and passes from the 
neck of the astragalus to the upper surface of the scaphoid. 
The Tarso-Metatarsal Articulation. 
The first metatarsal bone articulates with the internal cuneiform; the 
second, with the middle cuneiform, by its base, and laterally with the in- The Ligaments. 
97 
ternal and external cuneiform bones, being jammed between these and 
extending farther back than the other metatarsal bones; the third articu- 
lates with the external cuneiform, and the fourth and fifth with the cuboid. 
The tarsus is held to the metatarsus by dorsal and plantar ligamentous 
fibres and by three interosseous ligaments—one from the internal cunei- 
form to the second metatarsal and one from the external cuneiform to the 
third metatarsal. 
The metatarso-phalangeal, the inter-phalangeal and the “intermeta- 
tarsal ” are exactly similar to those of the hand. Notes on Anatomy. 
THE VISCERA. 
The Alimentary Canal and Appendages. 
The alimentary canal begins at the mouth and ends at the anus, the 
intermediate portions being found in the neck, thorax and abdomen. In 
the neck are the fauces, pharynx and part of the oesophagus; in the tho- 
rax is the remaining portion of the oesophagus, while the rest of the 
canal is found in the abdomen. 
The Mouth. 
The mouth begins at the lips and terminates behind in a short con- 
stricted portion called the fauces. It is bounded above by the hard 
palate, below by the tongue and on each side by the cheeks. 
The lips are two, upper and lower, separated by the transverse labial 
fissure. Each is formed chiefly by its segment of the orbicularis oris 
muscle, covered externally by skin and internally by mucous membrane, 
a concentric fold of which, called froenum labii, extends in the middle line 
from each lip to the gum behind. The cheek consists chiefly of the buc- 
cinator muscle, covered externally by skin and internally by mucous 
membrane, which is reflected from it to the gum and presents, opposite to 
the second molar tooth of the upper jaw, the opening, on a papilla, of 
Stenson’s duct from the parotid gland. The hard palate is formed ante- 
riorly by the meeting in the middle line of the palate processes of the 
superior maxillary, and posteriorly by the horizontal plate from each 
palate bone. It is bounded in front and at either side by the aveolar 
processes of the superior maxillary bones, containing the teeth of the 
upper jaw. It is covered by mucous membrane both above and below, 
forming the floor of the nasal fossae above and the roof of the mouth 
below; on the latter aspect the mucous membrane is roughened by 
glands, called palatal and is continued on to the gums. 
The floor of the mouth is formed by the anterior two-thirds of the 
tongue, the posterior third of the tongue forming the floor of the fau- 
ces, and, below that, entering into the formation of the anterior wall of 
the pharynx. The tongue is flattened from above downward, is coni- 
cal in shape and curved in direction, being convex above antero-poste- 
riorly, and extends from the hyoid bone behind to the incisor teeth in 
front, its base being adherent to the hyoid bone and its apex free and 
anterior. It is formed chiefly of muscular fibres, some of which are con- The Viscera. 
99 
fined wholly to the organ, and are called intrinsic muscles, while others 
are attached by only one end to the tongue, and are called extrinsic 
muscles. The tongue is covered on the superior surface, or dorsum, 
and on its sides by mucous membrane. Running through it from be- 
fore backwards is a vertical fibrous septum, thicker behind than in front, 
dividing it into symmetrical halves. The intrinsic muscular fibres are 
transverse and longitudinal—the transverse and longitudinal lingualis. 
The lingualis longitudinalis consists of fibres which extend from the 
hyoid bone, to which they are attached, to the tip of the tongue, and are 
found in a superficial layer on both the upper and lower surfaces of the 
organ, these two layers being separated by the lingualis transversalis, 
which consists of fibres attached to the fibrous septum and running out 
to the edge of the tongue. The so-called vertical lingualis is simply the 
continuation of the fibres of certain extrinsic muscles of the tongue, and, 
indeed, the longitudinal lingualis consists largely of such fibres. 
The extrinsic muscles of the tongue are the stylo-glossus, hyoglossus, 
and two others, one of which, the genio-hyoglossus, belongs with the 
elevators of the hyoid bone, where it is described; the other, the palato- 
glossus, is considered with the soft palate. 
Stylo-Glossus 
The stylo-glossus arises from the tip of the styloid process of the 
temporal bone, and, running downward and forward as a narrow band, 
18 lost on the side of the tongue. 
Action : It draws the tongue backwards into the mouth. 
Hyoglossus. 
The hyoglossus is a flat, quadrilateral muscle, which arises from the 
body and both cornua of the hyoid bone, and, passing directly upward, 
13 inserted into the side of the tongue, to the inner side of the stylo- 
glossus. 
Action: It carries the tongue downward and backward, increasing the 
s*Ze of the fauces. 
The mucous membrane covering the dorsum of the tongue passes 
ar°und the sides and tip, thus enveloping most of the organ, and leaves 
foe lower surface to become continuous with that lining the gum of the 
lower jaw. In contact with the posterior part of the dorsum is the front 
°f the epiglottis, which is held to it by three folds of mucous membrane, 
foe gfosso-epiglottic ligaments, middle and two lateral. 100 
Notes on Anatomy. 
The Fauces. 
The fauces, or isthmus of the fauces, is that narrow part of the ali- 
mentary canal which connects the mouth posteriorly with the front of 
the pharynx. It is about one and one-half inches long, about the same 
in width, and rather less in depth; the size, however, varying greatly, 
for its walls are chiefly formed of muscular tissue, which is peculiarly 
subject to reflex action. 
The roof of the fauces is the soft palate; the floor is a part of the dor- 
sum of the tongue; the sides are formed by two arching muscles, and, 
between them, the tonsil glands. The muscle in front is the palato-glos- 
sus, forming the anterior pillar of the fauces ; that behind is the palato- 
pharyngeus, forming the posterior pillar of the fauces. The wall, in 
every aspect, is covered by mucous membrane. 
Soft Palate. 
The soft palate, or velum pendulum palati, is thin and flattened from 
above downward and forward. It is attached above to the posterior 
border of the hard palate and hangs downward and backward, separating 
the fauces from the upper part of the. pharynx. It is prolonged, in the 
middle line below, by a nipple-like projection, some half an inch long, 
called the uvula. It is made up chiefly of muscular tissue and tendon, 
covered on both faces by mucous membrane, which above, is continuous 
with that lining the nasal fossae and, below, with that of the fauces and 
mouth. The proper muscles of the soft palate are three, the levator pal- 
ati, the tensor palati and the azygos uvulae, but in addition there are two 
others which have their origin in the soft palate—the palato-glossus and 
palato-pharyngeus. 
Levator Palati. 
The levator palati arises from the rough surface on the basilar surface 
of the petrous bone, near its apex, and from the cartilaginous portion of 
the Eustachian tube, and descends to be lost in the soft palate. Its name 
indicates its action. 
Tensor Palati. 
The tensor palati is a small muscle which forms a right-angle on it- 
self, hence its synomym of circumflexus. It arises from the scaphoid 
fossa of the pterygoid process, from the spinous process of the sphenoid 
bone and from the cartilaginous portion of the Eustachian tube, and, first 
descending vertically, then turning transversely inward around the ham- The Viscera. 
101 
ular process, it spreads out into a broad aponeurosis in the soft palate. 
Its action is indicated by its name. 
Azygos Uvulae 
From the posterior termination of the soft-palate there hangs pendu- 
lous, in the centre, a short, conical mass called the uvula, which, when 
dissected, is found to consist, exteriorly, of mucous membrane and, in- 
teriorly, of a pair of minute muscles, each of which, arising from the 
Palate spine, descends beside its fellow and is lost in the mucous mem- 
brane of the uvula. These two muscles were formerly considered as 
°ne, hence their name. It is their presence in the uvula which accounts 
for its constant and varied movement. 
Palato-Glossus. 
The palato glossus arises in the soft palate and passes downward and 
forward to terminate in the side of the tongue. 
Action; It constricts the fauces, hence its synonym of constrictor isth- 
nill faucium. It can also depress the soft palate. 
Palato-Pharyngeus. 
The palato-pharyngeus arises in the soft palate and passes downward 
and backward to enter the wall of the pharynx, where some of its fibres 
are lost, the rest being inserted into the posterior border of the thyroid 
cartilage. Its action is the same as the preceding muscle and its syno- 
nyrn, constrictor isthmii faucium posterior. 
Pharynx. 
Food, in order to reach the stomach, passes through four successive 
Portions of the alimentary canal. The first two of these have been de- 
scribed, viz: the mouth and fauces. Leaving the latter, food enters the 
Pharynx, whence it passes to the oesophagus, in which the pharynx ter- 
Irilnates, and the oesophagus conveys it to the stomach. 
Tut the pharynx not only serves as a channel for the food in its pas- 
Sage to the stomach; it also conducts air from the nostrils to the larynx; 
since the nostrils are above the mouth and fauces, the pharynx must 
0 extend upward beyond them, as it does, reaching the base of the 
. U - The opening of the pharynx into the larynx, through which air 
ransrnitted, is found on the front of the pharynx just below the fauces. 
e air found in the tympanic cavity also passes through the pharynx, 102 
Notes on Anatomy. 
by means of the Eustachian tubes, which open into the upper front part 
of the pharynx just behind the posterior nares. Seven openings are 
found in the pharynx, of which six open in front, viz • the two posterior 
nares, the two Eustachian tubes, the opening of the fauces, and that of 
the larynx. The seventh is the termination, inferiorly, of the pharynx in 
the oesophagus. The pharynx extends from the base of the skull to the 
oesophagus, which begins on the front of the body of the fifth cervical 
vertebra, i. <?., at the same level as the termination of the larynx, which 
lies on the front of the pharynx, and the commencement of the trachea. 
The pharynx is about four and a half inches long, tapering as it descends 
along the front of the upper five cervical vertebrae. 
Structures. 
The pharynx is lined by mucous membrane, resting on a thin fibrous 
coat. External to the mucous coat is a muscular coat, consisting, like 
that of the intestines, of circular and longitudinal fibres, but differing in 
that the muscular fibres are here red and not pale, and are gathered into 
bundles which are described as separate muscles. The circular fibres 
are arranged in flattened bundles on each side, each bundle intersecting 
its fellow of the opposite side on the middle of the back of the pharynx 
where they form a raphe. Each pair of bundles overlaps the lower edge 
of the pair above. When traced from the raph6 forward it is seen that 
these fibres do not encircle the entire pharynx but pass from its sides to 
seek firm neighboring points of attachment, from which to exert traction, 
thus leaving the front of the pharynx devoid of muscular fibres, this 
part of its wall being formed by mucous membrane alone. The larynx 
resting on the front of the pharynx, is in contact with the mucous mem- 
brane and is embraced by these circular fibres. These muscles, from 
their action, are known as the constrictors of the pharynx; and as there 
are three separate bundles, they are described as superior, middle and 
inferior constrictors. The direction of. their fibres is not horizontally 
backward but backward and upward. 
Inferior Constrictor 
The inferior constrictor arises from the oblique line on the ala of the 
thyroid cartilage and surface behind it, from the side of the cricoid car- 
tilage and from the two upper rings of the trachea It runs backward, 
its upper fibres passing obliquely upward, overlapping the middle con- 
strictor and is inserted into the raphe of the pharynx. The Viscera. 
103 
Middle Constrictor. 
The middle constrictor arises from both cornua of the hyoid bone, and 
the stylo-hyoid ligament, a fibrous cord extending from the hyoid 
bone to the styloid process. The fibres radiate somewhat, spreading out 
°n the side of the pharynx, and are inserted into the raphe. The infe- 
rior fibres are overlapped by the inferior constrictor, and the superior 
fibres overlap the superior constrictor. So great is this overlapping that 
when viewed from behind but little of the superior constrictor can be 
Seen, the raphe of the middle constrictor extending to the basilar process. 
Superior Constrictor. 
The superior constrictor lies just beneath the skull and is overlapped 
by the middle. It arises from the lower one-third of the internal ptery- 
goid plate, from its hamular process, from the pterygo-maxillary liga- 
ment, from the extremity of the molar ridge of the lower jaw, and by a 
few fibres from the side of the tongue. It passes backward, is inserted 
mto the raphe, which is attached to the basilar process. The upper edge 
°f this muscle presents a concave border, thus leaving an arched interval 
between it and the skull above, over which the fibrous tissue beneath the 
mucous membrane of the pharynx extends and is here so much thick- 
ened as to form a strong fibrous membrane. 
The longitudinal fibres of the pharynx are, like the circular, gathered 
mto bundles, of which there are two pairs. These are described as dis- 
tmct muscles arising from points above the pharynx and inserted into it. 
One of them, the palato-pharyngeus, has been described as a part of the 
soft-palate; the other is known as the stylo-pharyngeus. 
The stylo-pharyngeus arises from the inner side of the base of the sty- 
loid process and descends to the side of the pharynx, entering its wall 
between the superior and middle constrictors. Some of the fibres are 
Ost in the pharynx, while some are continued to the posterior border of 
fbe thyroid cartilage. Action—it elevates and widens the pharynx. 
Stylo-Pharyngeus. 
(Esophagus. 
The oesophagus continues the course of the alimentary canal from the 
termination of the pharynx, at the commencement of the trachea on the 
front of the body of the fifth cervical vertebra, down the front of the ver- 
tebral column, through the neck and thorax, to pierce the diaphragm at 104 
Notes on Anatomy. 
the oesophageal opening, opposite the tenth dorsal vertebra and terminate 
at the cardiac orifice of the stomach. It is about nine inches long. 
Relations—It first descends in the front of the two lower cervical and 
upper six dorsal vertebrae, and then continues its course, steadily diverg- 
ing from the middle line to the left. It first lies on the middle line, 
but in the lower part of the neck and upper part of the thorax curves to 
the left slightly; about the third dorsal vertebra it returns to the mid 
line which it follows to the sixth dorsal, where it finally inclines to the 
left and forward. 
For the study of its relations it may be conveniently divided into three 
portions. The first extends from its commencement to the first dorsal 
vertebra and lies in the neck; the second extends from the first to the 
sixth dorsal and lies in the upper part of the thorax in the back of the 
superior mediastinum; the third extends from the sixth dorsal to its ter- 
mination and lies in the posterior mediastinum. 
The relations of the first portion are as follows: In front is the trachea, 
to the left of which it has slightly curved at its termination. In the fur- 
row between it and the trachea on each side is the recurrent laryngeal 
nerve; behind, it is separated from the vertebral column by the longus 
colli muscle; on each side is the common carotid artery, the left being 
the closer, owing to the curve of the oesophagus to that side. It is also 
in relation, laterally, with the lower part of the lateral lobes of the thy- 
roid gland. 
The second portion has the following relations: In front, as far down 
as the fourth dorsal vertebra, is the trachea, which separates it from the 
transverse part of the arch of the aorta. Below this it has in front first 
the left bronchus and then the pericardium. Behind, it has the longus 
colli muscle, separating it from the vertebral column. At its commence- 
ment it has to its right the terminal part of the innominate artery 
and, to the left of the terminal portion, the first part of the left com- 
mon carotid and left subclavion artery. These are lateral relations of 
the first part also. To the left and slightly in front, above, is the thoracic 
duct, and in the groove between it and the trachea is the left recurrent 
laryngeal nerve; also to the left, below, is the descending part of the 
arch of the aorta and the commencement of the thoracic aorta. To the 
right of the. lower part is the terminal part of the right vena azygos; 
lastly, laterally it is covered by the pleura. 
The third portion has the following relations; In front is the pericar- 
dium and left pneumo-gastric nerve; behind, is the right pneumo-gastric 
nerve, the vena azygos major, some intercostal veins, the thoracic duct 
and, at its lower part, the thoracic aorta, its relations to which are as The Viscera. 
105 
follows; At its commencement it lies to the right of the aorta but at 
°nce inclines forward and to the left, so as to get in front; so that at its 
termination it is in front of the aorta and to the left. On each side it 
18 m contact with the pleura. 
Structure. 
The oesophagus consists of three coats, a mucous and two muscular. 
The muscular coats are external longitudinal and internal circular. The 
longitudinal fibres are uniformly diffused around the tube through most 
°f its extent, but above are gathered into three more or less distinct bun- 
dles; that in front attached to the cricoid cartilage and the others contin- 
uous with the pharynx; below, this coat becomes continuous with the 
stomach. The circular fibres above are continuous with the inferior con- 
strictor of the pharynx and below with the stomach. This coat is sepa- 
rated from the mucous membrane of the oesophagus by a sub-mucous 
connective tissue sometimes called the areolar coat of the oesophagus. 
The fibres of both muscular coats are, above, reddish and distinctly stri- 
ated, but below are pale and lose the striation. 
T he mucous membrane is loose and thrown into longitudinal folds when 
the tube is not distended. It presents numerous minute orifices of the 
ducts of the oesophagal glands which lie embedded in the sub-mucous 
tissue. 
The Abdominal Viscera. 
The cavity of the abdomen is bounded above by the diaphragm, which 
Is a thin arched muscle with its cavity downwards, forming the floor of 
the chest and the roof of the abdomen. The floor of the abdomen is 
the floor of the pelvis, i. e. the structures which close the outlet of the pelvis. 
Occasionally the floor is given as the brim of the true pelvis and the iliac 
f°ssae, the true pelvis being then considered a separate cavity. Laterally 
aud in front, from the lower ribs above to the ilium below, the abdominal wall 
18 formed of soft tissues, muscles, &c., and is the soft, fleshy, front wall of the 
hefly. At its upper part the cavity is partly circumscribed by the lower 
ri^s the last six or seven; below, by the bony wall of the pelvis; behind, by 
the lumbar portion of the vertebral column; while.on each side are, above, 
th * . 
e floating ribs, below, the pelvic wall, and, between the two, the soft 
bssues. For convenience of description the abdomen is arbitrarily divided 
lnto three zones, and each of these into three regions, by two horizontal 
and two vertical imaginary lines. The upper horizontal line is drawn 
ctween the extremities of the ninth ribs; the lower between the anterior 
Superior spinous processes of the ilia. The vertical lines, one on each 
Slde, are projected upward from the centre of the fold of the groin. 106 
Notes on Anatomy. 
The names of the nine regions are as follows: The central region in the up- 
per zone is the epigastric, the one on either side hypochondriac, right and 
left; the central region in the middle zone is the umbilical, the one on either 
side lumbar, right and left; the central region in the lower zone is the hypo- 
gastric, the one on either side, iliac, right and left. 
The contents of the abdomen are the greater part of the alimentary 
canal, the accessory organs of digestion—liver, spleen and pancreas—and 
the genito-urinary organs—kidneys and supra-renal capsules, the bladder 
and its appendages, prostate gland, seminal vesicles and vas deferens. 
The testicles are considered with the abdominal viscera, although, in the 
adult, lying in the scrotum, outside the abdominal cavity. In the female 
there are the uterus and its appendages and the vagina. Enveloping 
most of these organs, and lining the walls of the cavity, is a serous mem- 
brane, called the peritoneum. The following are the portions of the ali- 
mentary canal contained in the abdomen: ist, the stomach; 2d, small 
intestine; 3d, large intestine. The stomach is the dilated part which 
succeeds the oesophagus and is about twelve inches long. It terminates, 
about the line which separates the epigastric from the right hypochan- 
driac region in the small intestine. The small intestine is divided into 
three parts, duodenum, jejunum and ileum. The duodenum is about 
nine inches long; the jejunum and ileum, together about twenty feet, the 
jejunum comprising the upper two-fifths and the ileum the lower three- 
fifths. The duodenum is again subdivided into three portions, viz: first 
portion, ascending, or oblique duodenum, is about two inches long and 
terminates at the neck of the gall bladder, on the lower surface of the 
liver, in the right hypochondriac region in the second portion, called the 
descending, or perpendicular duodenum, which passes vertically down- 
ward for about three inches into the right lumbar region, about on a level 
with the upper border of the fourth lumbar vertebra, where it termi- 
nates in the third portion called the transverse duodenum, which is rather 
more than three inches long and crosses the front of the vertebral column 
obliquely upward and terminates at the left side of the body of the second 
lumbar vertebra, in the jejunum. The large intestine is subdivided into 
three portions called coecum, colon and rectum. The coecum is the com- 
mencing two and one half inches, lies on the right iliac fossa and termi- 
nates in the colon at the opening of the small intestine. The colon is 
divided into the ascending, transverse and descending colon and the sig- 
moid flexure. The ascending passes upward through the right lumbar 
region into the right hypochondriac. At the under surface of the liver 
it curves sharply to the left, forming the hepatic flexure of the colon, and 
becomes the transverse colon. The transverse colon passes downward The Viscera. 
107 
a°d to the left, crosses the abdomen between the epigastric and umbilical 
and rising into the left hypochondriac region forms another abrupt 
curve at the lower end of the spleen, called the splenic flexure of the 
colon, and becomes the descending colon. The descending colon passes 
downward through the left lumbar region into the left iliac where it be- 
comes the sigmoid flexure. The sigmoid flexure is formed by the gut’s 
Passing upward and to the right and then downward and to the left to 
terminate at the brim of the pelvis on the left side, in front of the left 
sacro iliac symphysis, by becoming the rectum. The colon is about four 
feet in length. The rectum is the last eight inches of the large intestine 
and terminates the alimentary canal at the anus, about the middle of the 
door of the pelvis. The liver lies in the upper zone of the abdomen, 
stretching nearly across the cavity just beneath the roof. The spleen is 
ln the left hypochondriac region. The pancreas lies transversely behind 
the stomach, between the spleen and perpendicular duodenum, crossing 
the front of the body of the first lumbar vertebra. Each of the two kid- 
neys is beside the lumbar portion of the spinal column, on the front of 
the posterior abdominal wall. The urinary bladder and its appendages 
are found in the pelvis just behind the os pubis. The uterus and vagina, 
ln the female, are interposed between the rectum and bladder. 
Reflections of the Peritoneum. 
The peritoneum, being a serous membrane, is a closed sac, one layer 
covering the viscera, and called the visceral layer, and the other lining 
the walls and called the parietal layer. The existence of the peritoneum 
renders the motions of the viscera upon one another, and upon the ab- 
dominal walls, easy and harmless and furnishes bonds of connection be- 
tween them and the walls of the containing cavity. Being a closed sac 
lts continuity can be demonstrated by the fact that in following it, trans- 
vcrsely or vertically, it can be traced back to the point of departure. 
The folds it makes from above downward are the most important and 
wdl be first stated. 
It leaves the lower surface of the diaphragm in two layers, which pass 
*° the upper and lower edge of the posterior border of the liver. The 
uPper layer covers the upper surface of the liver, curves around the an- 
terior border and coats the lower surface as far back as the transverse 
figure, where it meets the lower layer, which has covered the lower sur- 
lace from the posterior border to the transverse fissure. The two layers, 
having thus enveloped the liver, leave it at the transverse fissure and pass 
downward to the stomach, forming between these two organs the gastro- 
hepatic omentum, or the lesser omentum. 1 hev reach the stomach at its 108 
Notes on Anatomy. 
upper border and divide, one passing over the front and one over the 
back, and meet again at the lower border after furnishing a coat to the 
stomach. The two layers leave the stomach at its lower border and pass 
downward to the transverse colon, passing over it without touching and 
descend almost to the brim of the pelvis, just behind the anterior abdom- 
inal wall; they then reverse their course, run upward, just posterior to 
their descending course, reach the transverse colon, and, separating, en- 
close it. That part of the peritoneum extended between the lower border 
of the stomach and the transverse colon is called the greater omentum. 
The two layers, having enveloped the transverse colon, meet at its pos- 
terior border and pass back to the posterior abdominal wall, where they 
form the transverse mesocolon, which loosely holds the transverse colon 
to the posterior abdominal wall. The two layers now finally separate; 
one goes up the posterior abdominal wall to the lower surface of the dia- 
phragm, where its course was first taken up, thus partially enclosing a 
space behind the stomach called the lesser cavity of the peritoneum, 
which communicates with the general cavity through an opening behind 
the oblique duodenum, called the foramen of Winslow; the other layer 
passes forward to envelope the coils of the jejunum and ilium and returns 
to the posterior abdominal wall, forming a double layered fold, holding 
the intestine to the abdominal wall, called the mesentery. The attach- 
ment of the mesentery is thus stated: from the left side of the body of 
the second lumbar vertebra downward and to the right to the right sacro- 
iliac synchondrosis. After forming the mesentery the peritoneum de- 
scends the posterior abdominal wall to the brim of the pelvis passes 
down its posterior wall, covering the upper half of the rectum completely, 
leaves the front of the rectum an inch below its middle, strikes the back 
part of the base of the bladder, in the male, covers the back, sides and 
posterior half of the top of the bladder, and leaves the bladder to mount 
on the posterior face of the anterior abdominal wall and pass up it and 
reach its starting point on the lower surface of the diaphragm. In the 
female, when the peritoneum leaves the front of the rectum, it passes to the 
lower wall of the vagina, covering its upper inch, then strikes the uterus 
passing up its back and turning down its front whence it passes to the blad- 
der. In mounting over the top of the uterus it also passes over the 
ovary and its ligament, on each side, thus forming on each side a double 
layered fold stretching between the sides of the uterus and the lateral 
walls of the pelvis called the broad ligament of the uterus. Between 
these two layers are the ovary and its ligament, the round ligament of the 
uterus and the fallopian tubes. 
Followed transversely around the abdomen, about its middle, the peri- The Viscera. 
109 
toneum presents the following folds; commencing on the anterior abdom- 
]nal wall it can be followed to the posterior abdominal wall, where it 
reaches the descending colon and passes over it, covering it from half to 
three-fourths around; and, leaving it at a corresponding line on the inner 
side, it reaches the vertebral column where it turns forward to envelope 
the folds of the jejunum and ilium and to pass back on itself to the ver- 
tebral column, forming the mesentery; it then runs out on the posterior 
abdominal wall to reach the ascending colon, passes over its front, cover- 
lng it from half to three-fourths around, and, leaving it, reaches the ab- 
dominal wall again along which it runs to the place of departure. 
Relations of the Abdominal Viscera— 
Stomach. 
The stomach lies in the upper zone, in the left hypochondriac and epi- 
gastric regions, generally terminating in the duodenum on the line which 
Separates the epigastric from the right hypochondriac region, but occa- 
s'onally passing more or less into the latter. Its long axis is directed 
from above downward, from left to right and from behind forward; one 
surface looks forward, the other backward; one border, the shorter, or 
lesser curvature, upward, the other, the long, or greater curvature, down- 
ward; the large end is to the left, the small, to the right. It is continu- 
es with the duodenum at the right end. Its upper border is held to the 
lower surface of the liver by the lesser omentum; its lower border is in- 
directly held to the transverse colon by the greater omentum; its left end 
18 connected with the spleen by the gastro splenic omentum. Above it 
are the diaphragm and the left lobe of the liver; below is the transverse 
colon; to the right it is continuous with the duodenum; to the left is the 
Spleen; behind are the pancreas and left kidney; in front, the anterior 
abdominal wall and part of the left lobe of the liver. It has a complete 
Peritoneal coat. 
The Oblique Duodenum. 
The oblique, or ascending duodenum, commences at the right extremity 
°f the stomach, usually on the line which separates the epigastric from 
the right hypochondriac region, and passes upward and to the right, in 
the latter region, to terminate in the descending duodenum at the neck 
°f the gall bladder on the lower surface of the liver. It lies in the right 
border of the lesser omentum and has behind it the hepatic artery, the 
common bile duct and the portal vein. In front of it is the liver. It is 
completely invested by peritoneum, Notes on Anatomy. 
The Perpendicular Duodenum. 
The perpendicular, or descending duodenum, commences at the termi- 
nation of the oblique duodenum, at the lower surface of the liver, at the 
end of the gall bladder in the right hypochondriac region, and descends 
vertically into the lumbar region to terminate in the transverse duode- 
num, about on a level with the upper border of the fourth lumbar verte- 
bra. It lies behind the peritoneum, being covered by it only in front. 
Behind it has the right kidney and in front the ascending colon ; to the 
left it is adherent to the head of the pancreas. 
The Transverse Duodenum. 
The transverse duodenum commences where the oblique terminates, in 
the right lumbar region, on a level with the upper border of the body of 
the fourth lumbar vertebra, and passing upward and to the left, across 
the body or the third lumbar vertebra, terminates in the jejunum at the 
left side of the body of the second lumbar vertebra. It lies behind the 
peritoneum, between the diverging layers of the transverse meso-colon, 
so that it is covered by peritoneum only in front. Above it is the lower 
border of the pancreas, from which it is separated by the superior mesen- 
teric artery and vein; in front is the transverse colon. 
The Jejunum and Ileum. 
The remaining twenty feet of the small intestine, following the duo- 
denum, are thrown into coils called the convolutions of the small intes- 
tine, and are found chiefly in the umbilical and hypogastric regions, fall- 
ing off, however, into surrounding regions, some being always found in 
the pelvis between the rectum and bladder in the male and the rectum 
and uterus in the female. The jejunum comprises the upper two-fifths 
of the intestine and begins where the duodenum terminates, at the left 
side of the body of the second lumbar vertebra. The ileum is the lower 
three-fifths, and terminates in the right iliac region by opening into the 
large intestine two and one-half inches above its commencement. 
The convolutions are completely enveloped by the peritoneum, which 
holds them by a double-layered fold to the posterior abdominal wall. In 
front they are separated from the anterior abdominal wall by the great 
omentum; above is the transverse colon; to the right the ascending, to 
the left, the descending colon. The Viscera. 
The Coecum. 
The coecum is the commencement of the large intestine. It is two and 
one-half inches long and terminates in the colon at the opening of the 
small intestine. It lies in the right iliac fossa or region, and is generally 
completely invested by peritoneum. Attached to it is the vermiform ap- 
pendix, a blind tube about the size of a goose quill and from four to six 
inches long. It opens into the inner back wall of the coecum, just below 
the opening of the ileum, and not into the bottom. The appendix has a 
complete peritoneal coat and lies slightly coiled on the inner side of the 
coecum and just below the ileum. 
The Ascending Colon. 
The ascending colon commences where the coecum terminates, in the 
right iliac region, at the opening for the ileum, and passes upward through 
the right lumbar region into the right hypochondriac region where it 
terminates by becoming the transverse colon, forming the hepatic flexure 
°f the colon at the lower surface of the right lobe of the liver, to which 
A is held by a fold of the peritoneum, being covered by it in front from 
half to three-fourths around. In front and to the outer side is the ab- 
dominal wall; to the inner side, the convolutions of the small intestine; 
behind, the perpendicular duodenum and right kidney. 
The Transverse Colon. 
The transverse colon commences at the termination of the ascending 
colon, at the lower surface of the liver, in the hepatic flexure of the colon, 
and passes obliquely downward and to the left, crosses the abdomen be- 
tween the upper and middle zones, and, rising into the left hypochondriac 
region, terminates by forming the splenic-flexure of the colon at the lower 
cod of the spleen and becomes the descending colon. Its course is curved 
Vlth its convexity downward and forward. It is entirely covered by per- 
floneum, which holds it by a long doubledayered fold, the transverse 
tosso-colon, to the posterior abdominal wall and by a small band to the 
lower end of the spleen. It is indirectly held to the greater curvature of 
the stomach by the great omentum. In front it is separated from the 
anterior abdominal wall by the great omentum; behind is the transverse 
duodenum; above are the liver, stomach and spleen; below, the convo- 
lutions of the small intestine. 112 
Notes on Anatomy. 
The Descending Colon. 
The descending colon begins where the transverse colon ceases, in the 
left hypochondriac region at the lower end of the spleen, and passing 
downward through the left lumbar region terminates in the left iliac region 
by becoming the sigmoid flexure of the colon. It lies behind the peri- 
toneum, covered by it in front from half to three-fourths around. To its 
front and outer side is the abdominal wall; behind, the left kidney; to the 
inner side are the convolutions of the small intestine. 
The Sigmoid Flexure. 
The Sigmoid flexure of the colon begins at the termination of the de- 
scending colon, in the left iliac region, and curves upward and to the right 
and then downward and to the left to become the rectum at the brim of 
the pelvis in front of the left sacro-iliac symphysis. It is completely in- 
vested by peritoneum, which holds it to the iliac fossa by a long fold 
which permits it to fall in different directions. 
The Rectum. 
The rectum commences at the termination of the sigmoid flexure of 
the colon in front of the left sacro-iliac symphysis and passes first down- 
ward and to the right, to the middle of the front of the sacrum, then 
down the front of that bone to a point opposite the tip of the coccyx, 
where it turns slightly backward, and after a course of about an inch, ends 
at the anus. Its upper half is entirely covered by peritoneum, which 
holds it to the pelvic wall. Its lower half is covered by peritoneum only 
for an inch in front at its upper part; in other words, it is three inches 
from the anus to the peritoneum in front and four inches behind. Be- 
hind the rectum is the pyriformis muscle, the sacral plexus of nerves and 
the left internal iliac vessels; in front, from above downward, in the male, 
are the bladder and its appendages, in the female, the uterus and vagina. 
Interposed between it and the bladder, or uterus, are some convolutions 
of the small intestine. 
The Liver. 
The liver is found in the upper zone of the abdomen, the greater part 
being in the right hypochondriac and epigastric regions, but projecting, 
to a greater or less extent, into the left hypochondriac. Its long axis is 
transverse; its sharp notched border is in front and below, nearly corre- 
sponding to the lower margin of the ribs on the right; its thick border The Viscera. 
113 
13 backwards, resting against the diaphragm and grooved for the inferior 
Vena cava, and also, near the left end, for the oesophagus; its convex 
surface is above; its large end is to the right. 
It is held in place by five ligaments and is connected to the stomach 
by the lesser, or gastro-hepatic omentum. Four of its ligaments are 
°rmed by the peritoneum while the fifth, called the round ligament, is 
tbe remains of the obliterated umbilical vein. The peritoneum reaches 
the liver by two very short layers, which seize the one the upper the 
°ther the lower edge of its posterior border. These layers, on the pos- 
terior border, are separated by a considerable triangular space; but at 
each end they come together and form the right and left lateral liga- 
ments. Between these lateral ligaments the layers surrounding the tri- 
angular space form the coronary ligament. The upper layer is diverted 
forward from the liver, at a point about one-third the length of the liver 
from its left end, across the upper surface of the liver so as to surround 
foe round ligament by a double-layered fold called the suspensory liga- 
ment, or the longitudinal ligament, which holds the liver to the dia- 
phragm. The round ligament is that part of the obliterated umbilical 
vem which passes backward from the anterior abdominal wall to the 
n°tch in the anterior border of the liver, lying between the two layers of 
foe longitudinal ligament. The peritoneum reaching the liver in the 
manner described, passes over it, one layer over the upper surface, around 
foe anterior border to the transverse fissure where it meets the other 
tayer, which has run forward on the lower surface from the posterior bor- 
for, thus furnishing an almost complete peritoneal coat for the organ. 
Above the liver is the diaphragm; below it are, from right to left, the 
nght kidney with its supra-renal capsule, in front of these the hepatic 
flexure of the colon, behind, and to the left of this, the oblique duode- 
nurn, then the stomach, and lastly, the spleen, which is only an occasional 
relation. 
The Spleen. 
The spleen is confined to the left hypochondriac region. Its long 
diameter is vertical; its thin notched border is anterior; its smallest end 
18 below; its convex surface, external. It has a complete peritoneal coat 
ar*d is held in position by folds of peritoneum, one fold, called the sus- 
pensory ligament, passing from its upper end to the diaphragm, the 
°foer, called the gastro-splenic omentum, passing from its inner face to 
foe great end of the stomach. A third small fold extends from its lower 
end to the splenic flexure of the colon. 
Above it is the diaphragm from which it is sometimes separated by the 
IVer> below is the splenic flexure of the colon; behind the lower end is 114 
Notes on Anatomy. 
the left kidney and its capsule; in front, the anterior abdominal wall; in- 
ternal to it are the great end of the stomach and the tail of the pancreas; 
externally it corresponds to the ninth, tenth and eleventh ribs, from which 
it is separated by the diaphragm, the left pleura and the lower border of 
the left lung. 
The Pancreas. 
The pancreas extends from the inner face of the spleen on the left to 
the descending duodenum on the right. Its long diameter is transverse; 
its large end to the right; one surface looks forward, the other backward; 
one border is above, the other below. 
It rests on the front of the posterior wall of the abdomen, crossing the 
body of the first lumbar vertebra. It is behind the peritoneum, which 
covers it only in front. To its right is the perpendicular duodenum, to 
which it is closely adherent; to its left is the inner face of the spleen to 
which its tail is held by the peritoneum; in front is the stomach; behind 
its left end is the left kidney; below it is the transverse duodenum, from 
which it is separated by the superior mesenteric vessels. Its relations to 
blood vessels are very complex, and may be given as follows: it is sepa- 
rated from the vertebral column by the abdominal aorta, which produces 
the coeliac axis on a level with the upper border of the head of the pan- 
creas while the superior mesenteric artery is emitted just behind the head; 
the latter descending behind the pancreas, to pass out between it and the 
transverse duodenum. 
The coeliac axis, resting on the upper border of the head of the pan- 
creas, divides into three branches, one of which, the splenic, pursues a 
a very tortuous course along its upper border to the inner face of the 
spleen. This artery is accompanied by its vein, which passes to the right 
from the spleen, lying in a deep groove on the posterior face of the pan- 
creas just below its upper border. Behind the head of the pancreas the 
splenic vein unites with the superior mesenteric vein, which ascends be- 
hind the pancreas as the companion of its artery, the two veins forming 
the portal vein. About the middle of its course the splenic vein receives 
the inferior mesenteric vein which passes behind the body of the pan- 
creas. Surrounding the coeliac axis are the two semi-lunar ganglia of 
the sympathetic, giving off the numerous branches of the solar plexus of 
nerves, which are in close relation with the head of the pancreas. 
The Kidneys. 
The kidneys lie on the front of the posterior abdominal wall, extend- 
ing from about the eleventh rib downward and slightly outward to about The Viscera. 
115 
the crest of the ilium. The right is perhaps a little lower than the left, 
reaching only to the lower border of the eleventh rib while the left 
reaches to its upper border. The kidneys correspond to the last dorsal 
and the upper three lumbar vertebrae. They lie behind the peritoneum, 
embedded in a considerable mass of loose connective tissue, which usu- 
ally contains much fat. The peritoneum is loosely connected to the front 
°f the organ by this tissue and can easily be stripped off. The long di- 
ameter of the kidney is from above downward and slightly outward; one 
face looks forward and slightly outward, the other backward and slightly 
Jnward; the upper end is, perhaps, the larger; the outer border is convex, 
the inner, concave. Through most of its extent the kidney rests on the 
quadratus lumborum muscle, separated from it by the anterior lamella of 
the posterior aponeurosis, of the transversalis muscle. Along its inner 
edge it lies on the psoas magnus muscle, and behind its upper part is the 
diaphragm, which separates it from the pleura. The diaphragm here 
frequently presents a fissure of considerable size, where the muscular tis- 
sue is wanting, so that, in this event, all that separates the kidney from 
the pleura is a little loose connective tissue. Each kidney has upon its 
uPper inner front part the supra-renal capsule. The outer border is 
uearly opposite the outer border of the erector spinae muscle, and about 
corresponds to the junction of the posterior third with the anterior two- 
thirds of the crest of the ilium. 
The right kidney has in front the descending duodenum and in front 
°f that the ascending colon; along its inner border is the ascending vena 
Cava; its upper end is in contact with the lower surface of the liver, which 
ftay also rest on the front of its upper part. The left has on its front 
the descending colon and, at its upper part, the lower end of the spleen 
*he tail of the pancreas and the great end of the stomach. 
The Bladder, in the Male. 
The urinary bladder occupies the front portion of the pelvic cavity, 
being confined to it when empty or nearly so, but rising out of it accord- 
lng to its state of distension, occasionally reaching the level of the um- 
-1 lcus. It lies just behind the symphysis pubis with its long diam- 
ter from above downward and backward, extending from the upper 
rder of the symphysis pubis, or a point in the linea alba between it and 
the umbilicus, varying with distension, so that, if prolonged, it would 
strike the lower part of the front of the sacrum. 
The large end of the bladder is below and looks downward and back- 
ward. The viscus is retained in position by its ligaments which are ten 
ln number. Five of these are called false ligaments and are furnished by 116 
Notes on Anatomy. 
peritoneum, while of the five true ligaments four are processes of fascia 
and»one is the remains of a foetal structure, called the urachus. 
The peritoneum leaves the front of the rectum about three inches 
above the anus, and sweeps in a drooping course to the back part of the 
base of the bladder. This broad fold, extending from the front of the 
rectum to the bladder, is spoken of as the two posterior false ligaments. 
The division between them is purely arbitrary, being the middle line of 
the body. On each side, however, the fold presents an antero-posterior 
ridge, produced by the passage of the hypograstic artery from the pos- 
terior side of the pelvic wall to the side of the lower part of the bladder, 
the artery then passing up the side of the back of the bladder to the side 
of the top, whence it leaps to the anterior abdominal wall and approach- 
ing its fellow of the opposite side, makes for the umbilicus. In foetal 
life, this artery carries impure blood from the foetus to the placenta, 
emerging at the umbilicus; after birth it becomes impervious from the um- 
bilicus to the bladder, but from that point back to its origin from the in- 
ternal iliac it transmits some blood to the bladder. 
The peritoneum, reaching the bladder, covers the back part of its base, 
the back of the bladder, the posterior half of each side and the posterior 
half of the top, thence passing to the anterior abdominal wall, to which 
it is guided by the urachus and the obliterated hypogastric arteries. 
That part of the peritoneum extending from the middle of the top of the 
bladder to the anterior abdominal wall is called the superior false liga- 
ment; and that part on each side, extending from the side of the bladder 
to the lateral wall of the pelvis, forms the lateral false ligament. 
The four remaining true ligaments are formed by the pelvic fascia, which 
lines the pelvic cavity just beneath the peritoneum. From either side of 
the symphysis pubis a process of this fascia is extended to the lower part 
of the front of the bladder and prostate gland, these two being called 
the two anterior true ligaments of the bladder. From the lateral wall of 
the pelvis, on each side, a process of fascia passes to the side of the 
bladder, the two being known as the two lateral true ligaments of the 
bladder. 
The front of the bladder is separated from the back of the symphy- 
sis pubis only by a little loose connective tissue. The neck of the blad- 
der is received into the back part of the prostate gland and is continu- 
ous with the urethra, being about an inch behind and below the pubic 
arch. 
The posterior face of the bladder is separated from the rectum usually 
by some convolutions of the small intestine. The base of the bladder 
rests on the front of that part of the rectum which is found descending The Viscera. 
117 
the front of the sacrum, usually called the second portion of the rectum 
and is adherent to it. Piercing the posterior part of the base of the 
bladder on each side is the ureter, the two being about two inches apart 
e&ch having just internal to it the vas deferens, which, entering the ab- 
domen at the internal abdominal ring passes to the side of the top of the 
bladder, descends to its posterior face runs forward and inward along 
lts base to terminate at the front of the base by uniting with the duct, 
which forms the seminal vesicle to produce the ejaculatory duct. The 
seminal vesicles lie, one on each side, on the side of the base of the blad- 
der. They are pear-shaped, the base being behind and the apex for- 
Ward and inward at the back of the prostate gland. In the female the 
bladder, in general terms, occupies the same position as in the male. 
There are no prostate glands, no vas deferens or seminal vesicles. The 
base of the female bladder rests on the upper wall of the vagina, and on 
the lower part of the front of the uterus, which two separate it from the 
rectum. Otherwise the relations are about the same as in the male. 
The Stomach. 
In shape the stomach is a curved cone, with one border shorter than 
the other and its two sides, called anterior and posterior faces, some- 
what flattened. The short border is known as the lesser curvature, the 
as the greater curvature. The large end of the cone is to the left 
and is called the splenic end, because it is hugged by the spleen. At 
the left extremity of the lesser curvature, two or three inches from the 
eft end, is an aperture for the oesophagus, called the cardiac orifice. 
The splenic end of the stomach is the dilated cul de sac bulging beyond 
this. 
The right extremity of the stomach is much smaller than the splenic 
end and is called the pyloric extremity, because the opening of this end 
°f the stomach in the duodenum is called the pylorus. It is the smallest 
Part of the alimentary canal, being only an inch and a half in diameter. 
The position of the stomach is not directly transverse, but somewhat 
°blique) its long diameter being from above downward, forward, and to 
the right the cardiac orifice being on a higher level and farther back than 
the pyloric. When empty, the anterior and posterior faces look almost 
forward and backward respectively. 
The longest diameter of the stomach is about twelve inches, and it re- 
Ceives from one to two quarts of food at a time. 
The duodenum succeeds the stomach. It is about nine inches in 
The Duodenum. 118 
Notes on Anatomy. 
length and forms a horseshoe-shaped curve whose convexity is to the 
right. It is divided into three portions. The first portion, beginning at 
the stomach, is about two inches in length and is called the oblique por- 
tion. It passes upward, backward and to the right. The second portion, 
called the descending or perpendicular duodenum, is about three inches 
long and passes downward. The third portion, called the transverse 
duodenum, begins where the descending terminates and passing across 
the vertebral column, terminates in the jejunum, or second portion of the 
small intestine. The duodenum terminates at the left side of the second 
lumbar vertebra; but the point where the jejunum becomes the ileum is 
arbitrary and ill defined. The jejunum begins where the duodenum ter- 
minates and comprises the upper two-fifths of the remainder of the gut. 
The ileum comprises the remaining three-fifths and terminates in a sud- 
denly dilated portion called the large intestine. The jejunum and ileum 
together are about twenty feet long. They lie coiled up chiefly in the 
umbilical and hypogastric regions, producing an appearance somewhat 
similar to the upper surface of the brain, from which they are called the 
convolutions of the small intestine. 
The large intestine begins by a sudden dilation just below the termina- 
tion of the small intestine in the right iliac region, and extends to the 
termination of the alimentary canal at the anal orifice. 
The large intestine is about five feet in length. It is sinuous in its 
course and is divided into three portions, ooecum, colon and rectum. 
The entrance of the ileum is not into the extremity of the large intes- 
tine but two or three inches above its commencement. The blind pouch 
or cul de sac, which extends below this orifice is called the coecurn. 
This is the largest portion of the large intestine; it is about two and a 
half inches in length, lies in the right iliac fossa, is continuous with the 
colon above and has projecting from its lower, inner back part a tail-like 
hollow projection called the vermiform process, or appendix, which is 
from four to six inches in length and lies just below the terminal part of 
the ileum, its cavity being continuous with that of the coecurn. 
The colon is the second portion of the large intestine. It commences 
at the entrance of the ileum, which is the mark of division between it 
and the coecurn, in the right iliac region, and passes upward through the 
right lumbar region to the lower surface of the liver, in the right hypo- 
chondriac region. This portion of the gut is called the ascending colon. 
At the lower surface of the liver it makes a bend called the hepatic flex- 
ure of the colon, and turns to the left across the abdominal cavity. This 
portion is called the transverse colon and its course corresponds to the 
superior horizontal line of the abdomen. At the lower end of the spleen, The Viscera. 
119 
10 the left hypochondriac region, the colon makes another bend, called 
the splenic flexure, and turns downward to pass through the left lumbar 
region to the left iliac fossa, as the descending colon. In the left iliac 
fossa it makes another turn, first upward and to the right and then down- 
ward and to the left, forming the sigmoid flexure, which terminates at the 
hrirn of the pelvis, opposite to the left sacro-iliac symphysis, in the rec- 
tum. The rectum begins where the sigmoid flexure terminates and 
Passes downward on the front of the sacrum, to terminate at the anus, 
being approximately straight in its course—hence its name. 
Structure. 
The following coats, with slight exceptions, are common to the whole 
°f the alimentary canal found in the abdomen: 
Ist. The visceral layer of the peritoneum. 
2d. The interior coat is mucous membrane. 
3d. Between these two are found the longitudinal muscular fibres, ly- 
lng next to the serous coat, and 
4th- The circular, next to the mucous coat. 
These coats are held to one another by interposed connective tissue, 
0r areolar tissue. Each part, also, presents some point, peculiar to itself. 
The stomach has, ist, the serous coat which, besides investing it, passes 
°ff to adjoining parts forming the omenta of the stomach which seem to 
retain it in its position. It is held to the liver by the gastro-hepatic, 
0r lesser omentum, to the spleen by.the gastro splenic omentum and to 
the transverse colon by the gastro-colic, or greater omentum. 
2d. Just beneath the serous coat is the longitudinal muscular coat. 
3d. Just beneath this is the circular muscular coat, which is thickest 
l°ward the pyloric extremity, while the longitudinal is thickest at the 
iesser curvature. The fourth coat is a partial one, of oblique muscular 
bbres which diverge from the cardiac end of the stomach beneath the 
Clrcular fibres and terminate before reaching the pyloric orifice. The 
fifth coat is the internal mucous coat, which, when the stomach is empty, 
18 thrown into longitudinal ridges, called rugae, which disappear when the 
stomach is distended. At the pylorus the mucous coat is thickened, and 
beneath this thickening is an aggregation of the circular fibres so as to 
Produce a sudden contraction of the tube. This appearance is known as 
the pyloric valve. 
The duodenum has four coats; ist, serous; 2d, longitudinal muscular; 
3d, circular muscular; 4th, mucous membrane. In the commencement 
°f tb6 gut the mucous membrane is smooth, but it is soon thrown into 
fifids, which pass around the gut from three-fourths to five-sixths of its 120 
Notes on Anatomy. 
circumference; called valvulse conniventes. These valvulae conniventes 
are continued down into the jejunum and ileum, but gradually decrease 
in size and in the ileum are inconspicuous. They are permanent folds, 
not affected by distension. 
On the lower inner part of the perpendicular duodenum is a promi- 
nence of the mucous membrane, called a papilla, on which is seen the 
aperture for the common bile duct and the pancreatic duct. 
The jejunum and the ileum have the same coats, in the same order, as 
the duodenum. Studding the inner surface of the small intestine are 
numberless hair-like microscopic projections from the mucous membrane 
called villi; and besides these, and numerous mucous follicles which have 
their seat throughout the small intestine, there are some glandular bodies 
which have special seats. 
In the duodenum there are numerous small glands, about the size of a 
pin’s head, lying just beneath the mucous membrane and opening by 
ducts on its free surface, known as the glands of Brunner. Scattered 
throughout the small intestine, but much more numerous in the lower 
part of the ileum, are small, round, grayish bodies, in the mucous mem- 
brane, which have no duct and are called solitary glands. In the lower 
part of the ileum, and extending upward ten feet, or more—in a few 
instances into the duodenum—are found a number of dark, oblong, gray- 
ish patches, called Peyerian glands or Peyer’s patches. They are twenty 
to thirty in number. Sometimes there are as many as forty. The long 
diameter of these patches is in the direction of the gut. They are made 
up of an aggregation of the solitary glands and becomes diseased in 
typhoid fever. 
The opening of the small intestine into the large is by means of a hori- 
zontal slit-like opening, situated on the inner side of the large intestine 
two and a half inches above its commencement, and guarded by a valvu- 
lar arrangement called the ileo-coecal, or ileo-colic valve. This valve 
consists of two projections into the cavity of the large intestine, one 
above and the other below the button-hole like aperture, each segment 
being a fold of mucous membrane covering circular fibres of muscular 
tissue. 
The large intestine, like the small, has four coats, external serous, in- 
ternal mucous and between these two muscular, outer longitudinal, inner, 
circular. From the commencement of the gut to the rectum the longi- 
tudinal coat is not distributed uniformly around the gut, but the fibres 
are gathered into three narrow flat bands placed one in front, one on the 
back and one on the concave, inner side of the gut. These bands are 
shorter than the other coats of the gut, and in consequence the other The Viscera. 
121 
tunics are thrown into folds with corresponding depressions. These 
Prominences are known as the saculi of the large intestine. Towards 
the termination of the colon these bands begin to be diffused, and in the 
rectum the longitudinal fibres are again distributed and of equal length 
Wlth the other coats. The mucous membrane, in consequence of the 
shortness of the longitudinal muscular fibres, is also thrown into saculi. 
beneath it, especially in the upper part of the gut, are seen a number of 
solitary glands which differ from those in the small intestine in having a 
duct. 
The rectum presents some important departures from the above de- 
scription. It is usually divided into three portions. The first portion 
extends from the commencement of the gut until it ceases to incline to 
the right, that is until it reaches the mid line of the sacrum opposite the 
front of the body of the third sacral vertebra; the second, from this point to 
°ue opposite the tip of the coccyx; the third is the last inch of the gut. which 
here inclines backward to terminate at the anus. The rectum presents 
fhe same four coats, in the same order, with the following exceptions: The 
Serous coat is a partial one, the upper half of the gut being entirely sur- 
rounded by peritoneum while the lower half is covered by it for only an 
Jnch at its upper front part, from which point it mounts to the bladder. 
The fibres of the longitudinal muscular coat become much more distinct, 
snd of a reddish color, in the lower part of the gut; and, when they reach 
_ extremity, they do not stop short, but turn upward to run along the 
|nner face of the circular fibres, which separate them from the descend- 
lng longitudinal fibres, while the mucous membrane lies between them 
and the cavity of the gut. These ascending longitudinal fibres are gathered 
lnto separate bundles, or columns, which pass up for an inch or two before 
basing and throw the mucous membrane into ridges with intervening 
depressions called rectal pouches. Towards the lower extremity of the 
recturn the fibres of the circular muscular coat are aggregated into a 
thickened ring, internal sphincter ani, and just above this the cavity of 
the gut is considerably dilated, forming a capacious reservoir in cases of 
long continued constipation. 
The Liver. 
The liver stretches across the abdomen just beneath its roof, lying in 
the right hypochondriac, the epigastric and to some extent, the left hy- 
pochondriac region. It is semi-ovoidal in shape, weighs about four 
Pounds, is about twelve inches long, six broad and three thick, at its 
thickest part; in color it is a dull red with, occasionally, a purplish, or 
yellowish tinge. It is, in structure, a solid glandular organ. For study 122 
Notes on Anatomy. 
it is divided into an upper and a lower surface, an anterior and a poste- 
rior border, five ligaments and an excretory apparatus. 
The upper surface is smooth and convex, being moulded on the lower 
surface of the diaphragm. It presents a glistening appearance due to 
the visceral layer of peritoneum, which has been traced. The peritoneum, 
passing from the diaphragm to the liver in an antero-posterior fold, 
strikes the liver nearer the left than the right extremity. This fold, the 
longitudinal ligament, is a mark of division between the two lobes, all 
that portion lying to the right being known as the right lobe, while the 
much smaller portion, lying to the left is the left lobe. 
The anterior border is thin and sharp and has a notch at the point 
where the longitudinal ligament intersects it, which also marks the 
division between the lobes. The anterior border is just above the lower 
border of the ribs, though, when the liver is enlarged, it may be felt 
through the abdominal parietes. 
The posterior border is thick and rounded and marked by a notch 
where it is intersected by the longitudinal ligament, a third mark of 
division between the two lobes. The openings for the hepatic veins are 
found on this border, and it is grooved for the inferior vena cava. 
The lower surface is marked from before backwards by a fissure called 
the longitudinal, which is just opposite the longitudinal ligament on the 
upper surface, and extends from the notch in the anterior to that in the 
posterior border. It is the fourth mark of division between the lobes. 
The lower surface of the right lobe presents a deep groove, called the 
transverse fissure, which runs to the right from the longitudinal fissure 
which it strikes about at its posterior third. In this fissure are found 
the hepatic duct to the right and slightly in front, the hepatic artery to 
the left and between and behind the two the portal vein. That portion 
of the longitudinal fissure which is behind the intersection of the trans- 
verse fissure, is called the venosus fissure, and the portion in front the 
umbilical fissure. The latter is frequently crossed by a strip of liver 
tissue, called the pons hepatis. Lying in front of the transverse fissure, 
and producing an impression on the lower surface of the right lobe, is 
the gall bladder; and between this and the longitudinal fissure is a square- 
shaped portion of liver tissue called the lobus quaratus, whose limits are, 
in front, the anterior border of the liver, behind, the transverse fissure, 
to the right the gall bladder, to the left the longitudinal fissure. Behind 
the transverse fissure is another portion of liver tissue, which has re- 
ceived the name of lobus Spigelii, It is three sided, having in front the 
transverse fissure, to the left the venosus portion of the longitudinal 
fissure and to the right the groove made by the inferior vena cava. The Viscera. 
123 
Running out to the right from the front of the lobus Spigelii, just behind 
the transverse fissure, is a ridge, called the lobus caudatus. Near the 
Posterior border there is a depression on the lower surface of the right 
Rbe made by the right kidney and its suprarenal capsule. 
The liver is held in position by processes of peritoneum, called liga- 
ments, which are five in number. 
The longitudinal, or suspensory ligament consists of two layers of 
Peritoneum which pass from the lower surface of the diaphragm to the 
uPper surface of the liver. These two layers separate on reaching the 
hver and, with two exceptions, completely invest it. One exception is 
the space on the lower surface, occupied by the gall bladder, for the peri- 
toneum leaps over the gall bladder, investing it, and leaves the contigu- 
ous surfaces of gall bladder and liver uninvested. The other exception is 
found at the posterior border, for the two layers here diverge, to form the 
right and left lateral ligaments, which are nothing more than the points 
where the visceral and parietal layers come in contact; and between the 
two diverging layers, on the posterior border, there is a triangular space 
which has no serous coat. The two layers, as they skirt this space, are 
known as the coronary ligament. The fifth ligament is found as a 
founded cord in the front edge of the longitudinal ligament. It is the 
obliterated umbilical vein. 
The excretory apparatus consists of a series of ducts, and a reservoir, 
called the gall bladder. 
The gall bladder is a membranous pyriform sac, lying on the lower 
surface of the right lobe of the liver, its large end lying forward and 
usually falling short of the anterior border, though occasionally project- 
lng beyond it. Its small end lies backward and terminates at the trans- 
verse fissure in a neck which becomes continuous with a duct called the 
cystic. This duct is about one inch long and unites with the duct from 
the liver to form the common bile duct. The gall bladder has three 
c°ats. The external serous coat is only a partial one, since it passes over 
the gall bladder from the liver, leaving that portion next the liver unin- 
Vested. The next coat is fibro-muscular. 
The internal coat is mucous, and, in the neck, it is thrown into a spiral 
f°ld, so that liquid in following the spiral can flow but slowly. 
fn the transverse fissure two ducts, one from the right and one from 
|he left lobe, unite to form the hepatic duct, which is about two inches 
°n§ and descends to unite with the cystic to form the common bile duct— 
ductus communis choledochus—which descends for about three inches to 
°Pen on a papilla on the lower inner part of the perpendicular duodenum. 124 
Notes on Anatomy. 
Structure. 
The external investment of the liver is the nearly complete serous coat. 
Beneath this is a white fibrous coat which everywhere covers the liver, 
and gives off numberless processes which pass into the substance of the 
liver and divide it into minute subdivisions called lobules. These are 
made up of the proper liver substance. 
In the transverse fissure are three sets of vessels which ramify in the 
liver to fulfil the following offices: ist. The hepatic artery carries arte- 
rial blood to the liver. 2d. The portal vein also pours a stream of blood 
into the organ. 3d. The hepatic duct, resulting from the coalescence of 
the smaller ducts from the lobules, conveys the bile away from the liver. 
When traced into the liver these vessels are found associated through- 
out the organ. The venous blood is removed from the liver by means of 
a fourth set of vessels called the hepatic veins, which result from ramifi- 
cations associated with the other vessels but which open, by three, or four 
separate apertures, on the posterior border of the liver, into the inferior 
vena cava. 
The Pancreas. 
The pancreas is a pale, lobulated gland. It is six or seven inches long 
and varies in thickness from an inch and a half to less than half an inch. 
It weighs about three ounces and lies horizontally behind the stomach, 
with its large end or head embraced by the concavity of the descending 
duodendum, and its small end or tail in contact with the inner aspect of 
the spleen. It crosses the body of the first lumbar vertebra, which ren- 
ders its posterior aspect concave whereas its anterior is convex. The 
head is much the larger portion of the organ and sends downward, at 
right angles to the rest of the organ, a considerable projection from which 
the gland has been likened to a hammer. The head also furnishes a 
prominence backward and to the left which is sometimes called the lesser 
pancreas, and is found lying behind the superior mesenteric vessels. 
The Pancreatic Duct. 
The pancreatic juice is collected and conveyed away by a duct called 
the pancreatic, or canal of Wirsung, which commences in the tail of the 
organ by a forked origin. The two branches soon unite and the resulting 
duct, as it passes to the right grows by momentary accessions until it 
reaches the right extremity of the organ, where it pierces the coats of 
the perpendicular duodendum to open on the papilla for it and the com- 
mon bile duct. The Viscera. 
125 
Somewhere, just before leaving the pancreas, it receives the duct from 
the lesser pancreas. 
In structure the pancreas is a lobulated gland. It lies behind the peri- 
toneum, and, consequently, has a serous coat only in front. 
The Spleen. 
The spleen lies vertically in the left hypochondriac region. It is com- 
pletely invested by peritoneum, which forms two folds to retain it in posi- 
tton. The first is called the suspensory ligament and suspends the spleen 
hy its upper extremity to the lower surface of the diaphragm; the second, 
the gastro-splenic omentum passes between the inner surface of the 
spleen, and the contiguous large end of the stomach. 
In color the spleen is a dark red, in shape, semi-ovoidal, in consistence, 
extremely fragile, in size, about six inches long, three broad and one and 
a half thick, in weight, about seven ounces. It may be divided, for study, 
lnto two surfaces, two borders and two extremities. The external face is 
convex to correspond with the sweep of the abdominal wall; the internal, 
hat, or perhaps, concave, to hug the great end of the stomach, and 
Marked about its centre by a vertical groove, called the hilum, where the 
branches of the splenic artery find ingress and the vein egress, and where 
lhe gastro-splenic omentum is attached. The upper extremity is much 
|arger than the lower, which is thin and pointed. The posterior border 
18 thick and rounded; the anterior, thin, sharp and marked by one or 
notches. 
Structure. 
The spleen is invested by two coats, an external serous and, beneath 
a fibro-elastic coat, from the inner face of which are sent off pro- 
Cesses, or trabeculae, in the interspaces of which are found the proper 
splenic tissure or parenchyma, or splenic pulp. The spleen is a blood 
Vascular, or ductless gland, and whatever it elaborates is carried off with- 
°ut the aid of a special apparatus. 
The Kidneys. 
The kidneys are a pair of organs found, one on each side of the verte- 
ral column in the lumbar region, the left extending from the upper 
order of the eleventh rib to the crest of the ilium, the right from the 
Wer border of the same rib, being some one-half an inch lower than the 
e They about correspond to the twelfth dorsal and first and third lum- 
ar vertebrae, and diverge somewhat as they descend. Each is embedded 
ln a toass of fat behind the peritoneum, which touches them only slightly 126 
Notes on Anatomy. 
in front. Perched on the upper, inner part are the two supra-renal cap- 
sules. The kidney is about four inches long", two broad and one thick. 
It is peculiar in outline, hence the name reniform. The anterior surface 
is convex, the posterior, slightly flattened; the upper end is the larger; 
the outer border is convex, the inner, concave and presents a deep de- 
pression, called the hilum of the kidney, through which the duct and 
blood vessels pass, in the following order; the renal vein in front, the 
duct, or ureter, behind and the renal artery between the two. The hilum 
leads to a cavity in the organ, called the sinus. The kidney weighs four 
or five ounces. 
Structure. 
The kidney is invested by a fibrous coat, which can be easily stripped 
off, thus exposing the proper tissue, to study which the kidney should be 
split longitudinally, beginning at its external border and passing through 
its width. It is then seen to consist of two portions, an outer layer, red 
in color, which forms about three quarters of the organ, and within this 
is a portion of a lighter red forming the remaining fourth. The outer is 
called the cortical, the inner the medullary portion. The inner portion is 
made up of conical masses called pyramids of Malpighi; they are ar- 
ranged with their bases toward the cortical portion and their apices 
toward the hilum and are from eight to eighteen in number. Each pyra- 
mid consists of hundreds of straight tubules, leading from the cortical 
portion, where the urine is secreted, to the apex or papilla of the pyra- 
mid, where they discharge the urine. These pyramids are separated by 
prolongations of the cortical substance, which projects between them. 
The urine, which drops from the papilla, is carried off by coalescing 
ducts having different names, all of which finally terminate in one duct 
called the ureter, which in turn opens into the urinary bladder. The 
course can best be understood by following it from below up. Beginning 
with the ureter we find that, just before it reaches the kidney, it begins to 
enlarge forming what is called the pelvis of the ureter, which entering at 
the hilum, occupies the sinus of the kidney. The pelvis of the ureter 
soon divides into three tubes called infundibula, one infundibulum collect- 
ing the urine from each third of the organ. Each infundibulum, after a 
short course, subdivides into a number of short tubes called calices, each 
calyx terminating by surrounding the apex of one or more pyramids. 
The course of the urine, then, after secretion in the cortical portion is 
(ist) through the uriniferous tubules, which form the pyramids of Malpi- 
ghi (2d), dropping from the apex or papilla it falls into (3d) the calyx, 
which uniting with other calices from its third of the organ, forms (4th) 
an infundibulum, which combines with the other two infundibula to form The Viscera. 
127 
(sth) the pelvis of the ureter, which (6th) contracts to the ureter proper 
which, lastly, opens into (7th) the bladder. 
The Ureter. 
The ureter commences at the kidney in a dilated portion called the 
Pelvis, and, contracting to a small tube—about the size of a crow’s quill— 
Passes down beside the vertebral column to the brim of the pelvis, de- 
scends in the pelvis behind the bladder, and approaching its fellow, opens 
Jnto the back part of the base of the bladder. The apertures for the two 
ureters are about two inches apart, and the tubes pierce the coats of the 
bladder in an oblique direction. The length of the ureter is from sixteen 
to eighteen inches. 
The ureter—lying behind the peritoneum—consists of three coats, an 
eternal fibrous coat, an internal mucous, and, between these, an exter- 
nal longitudinal and an internal circular muscular coat. This descrip- 
fi°n applies to pelvis, infundibulum and calyx. Near the bladder there 
ls another layer of longitudinal muscular fibres lying between the circu- 
tar fibres and the mucous membrane. 
The Urinary Bladder. 
The bladder is the reservoir for the urine. It is a membranous sac 
which lies in the pelvis, just in front of the rectum, in the male, and of 
the uterus and vagina in the female. Its shape, when distended, is 
°voidal, or pyriform, the large end being below. When empty, it is 
battened against the pubes and is somewhat triangular. The direc- 
tlon of its long axis is downward and backward. The capacity of 
the bladder is very variable, though, in health, the urine is voided 
when half pint to one pint has been secreted. The upper third of the 
organ, about, is called the superior fundus, summit or apex; its middle 
third the body ; the lower third the base, or fundus. The channel 
through which the urine leaves the bladder is called the urethra, whose 
aPerture is seen in the lower front portion. This part of the bladder 
18 CaHed the neck, and lies embedded in the prostate gland. In struc- 
ture the bladder consists of the following coats: Ist. The internal is mu- 
c°us membrane. At the neck of the bladder there is a slight promi- 
nence, generally absent, called the uvula vesicae, seen just at the com- 
mencement of the urethra. Between the uvula vesicae in front, as its 
aPex, and the openings for the ureters, as its posterior angles, there is a 
triangular space called the trigonum vesicae, or triangle of the bladder, 
whose base is formed by a line drawn between the openings for the ure- 128 
Notes on Anatomy. 
ters, and whose sides are formed by a line on either side running from 
this point to the uvula and represented by a ridge in the mucous mem- 
brane made by a bundle of longitudinal fibres from the ureter. This 
space is by far the most sensitive part of the bladder, and corresponds to 
a similar space on the exterior of the base. 2d. The muscular coat is 
held to the mucous membrane by a layer of areolar tissue. It consists 
of longitudinal and circular fibres, the longitudinal forming two layers 
between which are found the circular. The circular fibres, at the neck 
of the bladder, are aggregated into a considerable mass, which by their 
tonic contraction, keep closed the opening of the urethra. 3d, The ex- 
ternal coat is serous and incomplete. In the male it covers the summit, 
sides, posterior aspect and posterior part of the base of the bladder, leav- 
ing uncovered the frontrand the front part of the base. 
The Urethra in the Male. 
The urethra is the last division of the canal which the urine traverses 
in seeking an outlet from the body. It commences at the neck of the 
bladder and terminates at the meatus urinarius, its opening on the free 
extremity of the penis. Its length is variously estimated, owing to the 
varying length of the penis which it tunnels. It is divided into three por- 
tions, the prostatic, which begins at the neck of the bladder and pierces 
the prostate gland to appear at its apex and become the second, or mem- 
branous portion, which passes on to enter the bulb of the corpus spongi- 
osum and become the third, or spongy portion. The spongy portion 
continues through the corpus spongiosum to terminate at the meatus uri- 
narius. It is the longest portion and the most variable in length. The 
length of the urethra as a whole is usually given, as seven and a half 
inches of which the prostatic portion occupies about one and one-fourth 
inches, the membranous three-fourths of an inch and the spongy portion 
the remainder. The prostatic portion is the largest. 
The Prostate Gland. 
This gland is a small horse chestnut-shaped body, found in the male, 
with its base against the neck of the bladder and its apex projecting for- 
ward. Its length is about one and one-fourth inches, its breadth, one 
and one-third, and its depth about one-half inch. It is invested in cellu- 
lar tissue and has a proper fibrous capsule; and it consists of interlacing 
unstriated muscular fibres, in the interstices of which are found the folli- 
cles of the gland, which secretes a milky fluid. It is divided into three 
lobes, two lateral and an inferior, or isthmus. Passing through it, nearer The Viscera. 
129 
lts upper than its lower surface, is the prostatic portion of the urethra. 
Cn the floor of this portion of the urethra is seen a prominence of the 
Mucous membrane, about one-half an inch long, called the veru mon- 
tanum. On either side of this prominence is a depression in the floor of 
the urethra, called the sinus prostaticus, in which are found some ten to 
fifteen minute apertures—the openings of the prostatic follicles; while in 
front of the veru montanum is a small saccular cavity, projecting back- 
Ward, called the sinus pocularis, or utriculus prostaticus, or uterus mas- 
culinus. Opening on either side of the orifice of this sinus is seen a 
small aperture, the opening of the ejaculatory ducts, which pass back, 
one on either side, to two lobulated oblong bodies, one on either side, 
JUst behind the prostate gland, called seminal vesicles. 
Seminal Vesicles. 
Each seminal vesicle is a reservoir for the seminal fluid, and is formed 
°f a tube, about the size of a goose quill, five or six inches long, coiled 
mto an oblong mass, which lies on the lower surface of the base of the 
bladder, its large end projecting backward and outward from its fellow, 
ffie small end being in front just behind the prostate gland and approach- 
es its fellow. The posterior extremities are about two inches apart, and 
a line drawn from one to the other is the base of a triangular space, 
apex is at the prostate gland, which may be designated as the in- 
tervesicular triangle. This space is devoid of peritoneum. The point 
wfiere the peritoneum strikes the base of the bladder corresponds to the 
Posterior boundary of this triangle, whose sides are formed by the semi- 
nal vesicles with the vas deferens of either side lying internal to them. 
Vas Deferens. 
Commencing at the upper extremity of the testicle the vas deferens 
forms one element of the spermatic cord, the others being blood vessels, 
nerves, &c., which ascends to the upper border of the pubes, where it 
Plunges into the anterior abdominal wall, through the external abdominal 
rJn§, then outward, along the inguinal canal to the internal abdominal 
ring, where it turns backward through that ring to enter the abdominal 
Cavity. As Soon as the cord enters the abdomen its various constituents 
fiEperse. The vas deferens passes to the upper part of the side of the 
adder, thence down its posterior surface, along the inner edge of the 
Serninal vesicles, at the anterior extremity of which it is joined by the 
tube, whose convolutions form the seminal vesicles, and the two form the 
eJaculatory duct. 130 
Notes on Anatomy. 
The Ejaculatory Duct. 
The two ejaculatory ducts lie very near each other and pass forward 
and upward, through the substance of the prostate gland, for about three- 
quarters of an inch, to open on the sides of the aperture of the sinus 
pocularis, which is found at the base of the veru montanum, in the floor 
of the prostatic portion of the urethra. 
The Penis. 
The penis consists of three cylinders, two, lying side by side called the 
corpora cavernosa, and one in a groove between these known as the cor- 
pus spongiosum. When dissected out the corpora cavernosa are seen 
to commence by attachment to bone—the ischio-pubic rami—by a por- 
tion called the crus which terminates posteriorly in a pointed extremity; 
while anteriorly it increases in size to become the corpus cavernosum. 
The corpora cavernosa do not extend to the extremity of the penis, but 
stop a little behind the meatus urinarius. The corpus spongiosum begins 
by a dilated portion called the bulb, situated between the crura, into 
which the membranous portion of the urethra passes to become the 
spongy portion. It. then passes forward, tunnelled by the urethra, lying 
between the corpora cavernosa, until it reaches their anterior extremity, 
when it suddenly dilates into a considerable mass, which covers the ex- 
tremity of the corpora cavernosa, and projects in a ridge beyond them. 
This dilated extremity is called the glans penis or head. The glans has 
its base backward, terminating in a rounded edge, raised above the sur- 
face of the corpora cavernosa, which is called the corona glandis, while 
the constricted portion behind it is called the neck. From the corona 
the glans slopes to its termination around the meatus urinarius. That 
portion of the penis extending from the crura, or rather where the three 
cylinders come in close relation, forward to the head, is called the body 
of the organ; and the two crura and the bulb constitute the root of the 
penis. 
Surrounding, and loosely adherent to, the body is a thin skin, which 
in front is formed into a fold, movable over the glans'called the prepuce. 
On the lower aspect of the glans the prepuce is attached by a process, 
extending forward to the meatus urinarius. This attached portion is 
called the fraenum. 
Passing through the corpus spongiosum from the bulb behind to the 
meatus urinarius in front, is the spongy portion of the urethra, which, 
just before its termination at the meatus, presents a considerable dila- The Viscera. 
131 
“on, called the fossa navicularis. The mucous membrane lining the ure- 
thra presents many follicles, called lacunae, opening into the canal. When 
the mucous membrane reaches the meatus it is continued over the glans 
Penis and the deep surface of the prepuce. 
The tissue of the three cylinders is that known as erectile tissue. Each 
cylinder is enveloped by a strong fibrous sheath, that of the corpus 
sPongiosum being more delicate than the others. Within this sheath the 
structure consists of interlacing bands of fibrous tissue, the interspaces 
between which contain dilated blood vessels, which when turgid with 
biood, produce erection. The two corpora cavernosa, at the posterior 
Part of the body of the organ, are separated some little distance from 
each other, but as they pass forward, come much closer together, for the 
bbrous tissue between them is thick posteriorly, whereas in front it is thin 
and presents numerous slit-like interruptions which have obtained for it 
name of septum pecteneiform. 
The Testicles—Testes. 
The testicles are a pair of small organs whose function it is to secrete 
lbe semen. They are found suspended by the spermatic cord, in the bag 
called the scrotum, separated from each other, although lying side by side. 
Each testicle weighs from three-fourths to one ounce or more; it is an 
lnch to an inch and a half long, about an inch antero-posteriorly and half 
an inch transversely. It occupies the back of the scrotum, its position 
being from above downward and backward. 
The scrotum is thus constituted: ist, an external covering of skin; 2d, 
beneath this a musculo-fibrous covering called the dartos; 3d, lining the 
lnterior of the dartos, and also enveloping the testicle, a serous mem- 
brane called the tunica vaginalis. That portion of the tunica vaginalis 
fining the dartos is called the parietal, and that lining the testicle the vis- 
ceral layer. 
There are two cavities in the scrotum separated by a septum from the 
bartos called septum scroti. There is a tunica vaginalis for each testicle. 
Structure of the Testicle. 
the visceral layer of the tunica vaginalis is removed we find be- 
neath a bluish white fibrous investment of the testicle called the tunica 
nginea. This is much thickened at the back part, where it is called 
t e niediastinum. 
Lining the inner aspect of the tunica albuginea is a reddish vascular 
lnvestrnent called the tunica vasculosa. Lying on the posterior aspect 132 
Notes on Anatomy. 
of the testis is a flattened body called the epididymis, which is made up 
of the convolutions of the tube conveying away the semen. The upper 
portion of the epididymis is alone permanently connected with the tes- 
ticle, for it is here that the ducts, which transmit the semen from the 
testes, emerge and unite to form the epididymis. The upper portion of 
the epididymis is called the globus major, the lower portion, which ter- 
minates in the vas deferens, the globus minor. The intermediate por- 
tion is called the body. The semen is secreted in what are called the 
lobules of the testicles, which number from 250 to 400, each lobule being 
separated from those adjacent by septa sent in from the tunica albuginea, 
which septa, however, are covered on both sides by a layer from the 
tunica vasculosa. 
Each lobule consists of the convolutions of a small tube some one-two 
hundreth of an inch in diameter, arranged from before backward with the 
large end of the convoluted mass in front and the small end behind at the 
mediastinum, where many lobules unite to form a single duct, which, from 
its comparatively straight course, is called the rectum. In the testis there 
are from twenty to twenty-five vasa recta, which plunge into the mediasti- 
num and there unite to form from two to twelve ducts, which ascending 
through the mediastinum in a sinuous course, are called collectively the 
rete testis. When the ducts reach the upper extremity of the mediasti- 
num, they terminate in from nine to thirty other ducts, called vassa-effe- 
rentia, each of which is thrown into convolutions assuming a conical ap- 
pearance which are known as coni vasculosi and form the globus major. 
The bases of the cones terminate in large ducts which unite in the body 
of the epididymis into one duct whose convolutions, some twenty feet 
long, form the body and globus minor of the epididymis and then be- 
come the vas deferens. 
The continuous course of the semen is then, lobule, which may be 
composed of as many as three tubes, vasa recta, rete testes, vasa efferen- 
tia, coni vasculosi, epididymis, body and globus minor, vas deferens. 
The JErial Apparatus. 
The air reaches the lungs from the throat through a tube which has 
received different names in its various parts. It is first called the larynx, 
then the trachea, which, opposite the fifth dorsal vertebra, divides into 
the two bronchi. 
The Larynx. 
The larynx is formed upon a framework of separate cartilages which 
require to be studied under individual names. The Viscera. 
Thyroid Cartilage. 
The thyroid is the upper, the front and the largest cartilage of the 
larynx. In front it comes to an acute angle and produces the promi- 
nence, called the Adam’s apple, pomum Adami. From this acute, or 
receding angle, it passes backward and outward on either side in a quad- 
r'lateral plate called the ala of the thyroid cartilage. On the outer sur- 
face of the ala is an oblique ridge, running from above downward and 
forward, terminating at each end in a prominence, or tubercle. The pos- 
terior border is rounded and free and prolonged both above and below 
into processes called the superior and inferior cornua, each terminated by 
a tubercle. The superior cornu is the longest. The upper border is 
slnuous. Commencing in the notch at the receding angle it passes back- 
ward to become continuous with the superior cornu. The inferior border 
18 also sinuous and continuous with the inferior cornu. 
Cricoid Cartilage. 
The cricoid cartilage is a ring and lies supporting the thyroid, between 
whose inferior cornua it is grasped. It is narrow in front—not more than 
°ne-fourth of an inch deep—but a full inch in depth behind. Its upper 
border slopes upward and backward, presenting in the centre, behind, a 
sbght notch, and, on either side of this an articular facet, on which is 
Perched another cartilage the arytenoid. Running down the middle line 
behind is a ridge, on either side of this a slight depression, and, further 
forward, on the side of the cartilage, a rounded, articular facet, for the 
lnferior cornu of the thyroid cartilage. 
Arytenoid Cartilages, 
The arytenoid cartilages are found upon the cricoid, occupying the 
frtlcular facets on its upper border. The cartilage is triangular in shape, 
lts base below and its apex above; its posterior surface concave, its ante- 
rior equally convex; its inner face, which looks towards its fellow, narrow 
an<3 flat. The apex is surmounted by another small cartilage called cor- 
nicula laryngis. The two arytenoid cartilages occupy the interval be- 
tween the alae of the thyroid cartilage. 
Epiglottis, 
j The epiglottis lies just above the receding angle of the thyroid carti- 
It is leaf shaped, its apex downward and forward and its base, 134 
Notes on Anatomy. 
which presents a slight notch, upward and backward and lying at the 
base of the tongue. Its upper end may be sometimes seen by looking 
down the throat. 
These several cartilages are held together and to the hyoid bone by 
the following ligaments. The hyoid bone lies just above the superior 
border of the thyroid cartilage and passing between them is an unbroken 
membrane called the thyro-hyoidean, and in each of the posterior edges 
of this membrane a rounded cord, which passes from the superior cornu 
of the thyroid cartilage to the posterior extremity of the hyoid bone, 
called the thyro-hyoid ligament. 
The thyroid and cricoid cartilages are held together by the following 
ligaments. The extremity of each inferior cornu of the thyroid cartilage 
is held to the facet on the side of the cricoid by a capsular ligament. 
The considerable interval which exists in front between the lower border 
of the thyroid and upper border of the cricoid is closed in by a fan- 
shaped yellow elastic membrane, called the crico-thyroid membrane, 
which is attached below to the upper border to the cricoid and above 
to the lower border of the thyroid for about one-fourth of an inch on 
each side of the middle line and then presents -a free edge, covered by 
mucous membrane, which posteriorly is attached to the anterior angle 
of the base of the arytenoid cartilage, forming the lower, or true vocal 
chords. 
Passing now to the epiglottis, we find its apex held to the receding 
angle of the thyroid by a narrow ligament called thyro-epiglottic. It is 
connected to the hyoid bone by a ligament called hyo-epiglottic, which 
is attached to the epiglottis on its front edge near its apex. The back of 
the tongue and the epiglottis are connected by three ligaments, one in 
the centre and one on each side, called glosso-epiglottic, middle and late- 
ral. Lastly we have the ligaments attached to the arytenoid cartilages, 
the base of each being held to the cricoid by a capsular ligament, the 
posterior part of which is thickened and called crico-arytenoid. Besides 
these the arytenoid cartilage is connected to the receding angle of the 
thyroid by means of two long ligaments. They are attached behind to 
the base of the arytenoid, one above the other, and in front to the reced- 
ing angle of the thyroid. The lower one is called the inferior thyro- 
arytenoid ligament and it and its fellow constitute the true vocal chords, 
these being the upper edge of the crico-thyroid membrane. 
The larynx is lined by mucous membrane continuous with that of the 
mouth. Looking into the cavity of the larynx from below, at a certain 
point, the cavity is suddenly narrowed by two ridges, one on either side, 
running from before, where they are close together, backward, diverging The Viscera. 
135 
as they go and leaving a triangular interval between them called the 
chink of the glottis, or rima glottidis; these ridges are produced by the 
mferior-thyro arytenoid ligaments, or true vocal chords. Reversing the 
larynx and looking into its cavity from above, the opening into it from 
the pharynx is seen to be limited by the epiglottis*which projects upward 
and backward. Over the opening, posteriorly, are seen the arytenoid 
cartilages; laterally are folds of mucous membrane, the ventricular 
bands; the opening is heart shaped with its broad end in front. Down 
ln the cavity are seen the ridges on each side, one above the other. The 
lower pair are those seen from below; the upper correspond to the supe- 
rior thyro-arytenoid ligaments and are the false vocal chords. As they 
are much less prominent than the true chords, they cannot be seen when 
the cavity is viewed from below. The space between the false vocal 
chords bears no name, but the similar and smaller space between the true 
chords is known as the rima glottidis. On each side of the glottis is 
another space formed by the recession of the walls of the larynx, between 
the true and the false vocal chords, which is called the ventricle of the 
larynx, and this space is continued up on the outside of the false vocal 
chords, between it and the wall of the larynx, some distance. This pro- 
longation of the cavity is known as the sacculus laryngis. To get a defi- 
ne idea of the ventricle and larynx, consider them as having the follow- 
lng boundaries: the ventricle is bounded on the outer side by the wall of 
the larynx, ala of the thyroid cartilage; on the inner side is the space 
called the glottis; above are the false vocal chords and the sacculus 
laryngis; below, the true vocal chords. The glottis is bounded above 
by the nameless interval between the false vocal chords; below, by the 
rinia glottidis; on each side, by the ventricle, for it lies between the two 
ventricles which extend from the wall of the larynx inward only as far as 
a line drawn from the inner edge of the false to the inner edge of the true 
vocal chords. 
Trachea. 
Succeeding the larynx comes the second subdivision of the air tube 
known as the trachea. Commencing where the larynx terminates, oppo- 
se the fifth cervical vertebra, it descends in front of the vertebral 
column, from which it is separated by the oesophagus, and terminates by 
dividing, opposite the fifth dorsal vertebra, into the right and left 
bronchi. It is a cylindrical tube, flattened on its posterior aspect, about 
lour and a half inches long and one inch in diameter. In the female 
these dimensions are somewhat less. Its appearance, when viewed from 
the front, is annulose, due to the fact that its largest element is a num- 
ber fifteen to twenty—of cartilaginous rings, one lying above the other. 136 
Notes on Anatomy. 
The flattening posteriorly is due to the fact that each ring is wanting in 
its posterior third, thus leaving this portion of the tracheal wall wanting 
in cartilage. The rings are not in contact but are separated, and at the 
same time maintained in position by a fibro-elastic membrane, which 
covers both surfaces of the rings, for they, in fact, lie embedded in the 
substance of the membrane. Between the posterior extremities of the 
rings, over the interval left by their imperfection, the membrane is con- 
tinued and is here strengthened by unstriated muscular fibres, both longi- 
tudinal and transverse. The longitudinal are unimportant; but the 
transverse, passing between the posterior extremities of the rings, can, 
by their contraction, diminish the diameter of the trachea. 
The interior of the trachea is lined by mucous membrane, continuous 
with that of the larynx above and prolonged below into the bronchi, 
bronchial tubes and ultimate air cells of the lungs. Beneath the mucous 
membrane, between it and the fibro-elastic membrane, is a yellow elastic 
membrane which is much more distinct posteriorly, where the fibres 
which compose it are gathered into longitudinal bundles. To sum up 
its structure we say the trachea is lined by mucous membrane, beneath 
this yellow elastic fibres, external to this a yellow fibro-elastic mem- 
brane lying in which are the rings of the trachea. Besides these there 
are transverse muscular fibres between the posterior extremities of the 
rings, and, scattered around the tube some unimportant longitudinal 
fibres. 
Thyroid Gland. 
Lying in relation with the upper part of the trachea and the larynx is 
a ductless gland called the thyroid. It consists of two similar lobes, each 
about two inches long and three-fourths of an inch in diameter, conical 
in shape with its base below and apex above. These two lobes lie one 
on each side of the upper part of the trachea, and are usually connected 
by a third lobe, or isthmus, which is a narrow strip passing across the 
front of the second and third rings of the trachea to the base of the other 
lobe, the apex of each lobe passing up beside the larynx. The color is a 
brownish red. The weight is about one and one half ounces. In the 
female it increases in size at each menstrual period. 
In structure the gland consists of numerous lobules, which are made up 
of many vesicles, containing a peculiar fluid, cells and nuclei, besides 
which is a network of blood vessels, for the gland is extremely vascular, 
each lobe receiving two large arteries, one from above and the other from 
below. Its constituents are held together by areolar tissue, which sepa- 
rates its lobules. The Viscera. 
137 
Bronchi, 
Taking up the air tube again, we find that the trachea, or wind pipe, 
when it has reached a point corresponding to the front of the fifth dorsal 
vertebra, forks, the prongs of the fork being known as the bronchi, right 
and left. Each bronchus extends from its origin to the inner surface of 
the lung, forming one element of the root of the lung. The two bronchi 
are not similar and the difference between them may be thus stated: The 
right is shorter, larger and more nearly horizontal, coming off nearly at 
right angles to the trachea, whereas the left has a considerable obliquity 
downward. If the trachea be cut across near its termination and the 
cavity examined, a slight antero posterior ridge is found separating the 
two bronchi. This ridge lies nearer the left than the right side and in 
consequence a foreign body falling into the trachea is more likely to en- 
ter the right than the left bronchus. The left bronchus is about two 
teches long, the right about an inch. In structure they exactly resemble 
the trachea. 
Lungs. 
The lungs are a pair of organs found in the thoracic cavity, one on 
each side of the middle line, resting upon the diaphragm below and 
having the heart enclosed in the pericardium, lying between them. Each 
is conical in shape with its base below, resting on the upper surface of 
the diaphragm and concave in shape to correspond with that surface. 
The apex is above and extends about one and one-half inches into the 
r°°t of the neck. Besides the base and apex, each lung presents the 
following subdivisions: the posterior border, long, thick and rounded, 
contrasting strongly with the anterior, which is thin, short and sharp. 
The outer surface is convex to correspond with the concave inner face of 
the chest wall. The inner face, which looks towards its fellow, is marked 
by 
a concavity which is caused by the heart, in the pericardium, which 
hes between the two lungs. The inner surface of the left lung is much 
atore concave than that of the right, owing to the inclination of the heart 
t0 the left. A little above and posterior to the centre of each lung on its 
lnner face the root is seen to enter its substance. The root is made up of 
various elements, nerves, lymphatics, &c,, but its chief constituents are 
the bronchus, pulmonary artery and two pulmonary veins. From be- 
hind forward, the relation these structures bear to one another is the same 
f°r both lungs, viz: Bronchus, artery, vein: but from above downward 
the relation is different in the two lungs. In the right it is bronchus, 
arter.V, vein; in the left, artery, bronchus, veins. The veins, on both 138 
Notes on Anatomy. 
sides, are the lowest, and the difference is caused by a change in the re- 
lation of the artery and bronchus in the left lung, which is accounted for 
by the downward inclination and greater length of the left bronchus. 
Each Jung is divided by fissures into lobes, the right into three and the 
left into two. Commencing about three inches from the apex, on the 
posterior border of each lung, an oblique fissure passes through the lung 
downward and forward to near the lower extremity of the anterior bor- 
der. In the right lung there is another fissure which begins near the 
centre of the oblique fissure and runs nearly horizontally forward to the 
anterioi border, thus dividing the right lung into three lobes known as 
upper, middle and lower. In the left lung there are but two lobes, upper 
and lower. The right lung is slightly larger than the left, owing to the 
encroachment of the heart on the left lung. The right, however, is 
shortened by the right lobe of the liver, which bulges the diaphragm on 
that side, and the difference is in reality not great—the right lung weigh- 
ing about twenty-two and the left twenty ounces. 
The Pleurae. 
Enveloping each lung and lining the chest wall is a serous membrane, 
one on each side. These two membranes are the two pleurae. They 
are separate from each other and each forms a distinct closed sac for its 
lung, one face of the sac lining the inner surface of the chest wall while 
the other completely invests the lung. In front, behind the sternum, the 
two pleurae approach each other closely, and are sometimes in contact 
about the centre of the sternum. 
In tracing the reflections of the pleura, as it is a closed sac, we can 
begin at any point and following it around will return to that point. 
Beginning on the root of the lung we trace first the visceral layer, or 
pleura pulmonalis, and then the parietal layer, or pleura costalis, the two 
being continuous. From the front of the root, the pleura passes forward 
on the inner face to the anterior border of the lung, then around the con- 
vex outer surface to the posterior border and then forward on the inner 
face to the back of the root of the lung and then to the side of the ver- 
tebral column, where it becomes the parietal layer, which passes thence 
along the inner surface of the chest wall to the sternum in front, where it 
leaves the chest wall and passes backward on the pericardium to the front 
of the root of the lung to become continuous with the visceral layer which 
we have just traced. The free surfaces of the two layers secrete a small 
amount of liquid which renders the movements of the lungs in respira- 
tion easy. The Viscera. 
Structure. 
Each lung has an external serous coat, the pleura, beneath which is an 
areolar elastic coat, which sends processes into the substance of the lung 
to separate it into numerous subdivisions, called lobules, where the func- 
tion of the lung, the aeration of the blood, is effected. As soon as the 
bronchus reaches the lung it forks into bronchial tubes and these ramify 
throughout the lung continuously subdividing, generally by forking, 
until they finally open into the air cells which form the lobules, there 
being several thousands of these cells in each lobule, say, 20,000, every 
lobule having one bronchial tube. On the walls of these cells the blood 
vessels ramify. These walls separate adjacent cells, which open into a 
common cavity, called an intercellular space, with which the bronchial 
tube communicates. The bronchial tubes differ in structure from the 
bronchus. At first the only difference is that the cartilages cease to be 
nng shaped and become flat and scale like and scattered all around the 
tube; but toward the termination of the tube the cartilages disappear en- 
tirely and the tube consists altogether of fibrous tissue, in which are many 
clastic fibres, muscular fibres and mucous membrane. The diameter of 
the smallest tubes is from one-fiftieth to one-thirtieth inch, and of the air 
cells from the one-two*hundredths to the one-seventieth of an inch. 
Before birth the lungs are almost colorless, but, as soon as the blood 
reaches the wall of the air cells, the lung assumes a pink color, which, 
during life, gradually fades to a slate color; and this, in the decline of 
Hie, may change to an almost black hue, especially in men and in the 
posterior part of the lung, owing to the deposition of minute particles of 
carbon. 
The Mediastinum. 
Between the opposing surfaces of the pleurae and the sternum in front 
and vertebral column behind, there is a space, called the mediastinum, 
which is divided into the superior mediastinum, all that part above the 
level of the pericardium, and the inferior mediastinum which is further 
subdivided into three portions, anterior, posterior and middle. 
The superior mediastinum is bounded below by a plane extending from 
tbe junction of the gladiolus and manubrium sterni to the lower part of 
the body of the fourth dorsal vertebra. 
The anterior mediastinum is bounded in front by the sternum and 
lower costal cartilages of the true ribs, behind by the pericardium and on 
either side by the pleura. It is oblique in direction, from above down- 
ward and to the left and is larger below than above. 140 
Notes on Anatomy. 
The middle mediastinum is the broadest part of the inter pleural space 
and contains the heart and pericardium. 
The posterior mediastinum is irregularly triangular, being bounded in 
front by the pericardium and roots of the lungs, behind by the vertebral 
column and laterally by the pleurae. It extends from the fourth dorsal 
vertebra downward and contains many important cords. 
The Heart. 
The heart is a hollow muscular organ found in the cavity of the chest, 
lying between and almost surrounded by the two lungs; it rests upon the 
convex upper surface of the diaphragm and is contained in the middle 
mediastinum. It is contained in a closed cavity, formed by the pericar- 
dium, lying, for the greater part of its extent, unattached; but, since its 
function is the maintenance of the circulation of the blood, the vessels 
which bring this to, or carry it from the heart all communicate with its 
upper part or base, and thus maintain it in position. To render its 
movements free in the pericardium, that structure is lined by a serous 
membrane which, like all others, is a closed sac, one layer lining the peri- 
cardium and the other covering the heart from the origin of the vessels 
on one side to the same point on the opposite side. The portion lining 
the pericardium is called the serous pericardium and the membrane 
which it lines the fibrous pericardium. The heart is conical in shape, its 
base being above and to the right and its apex below and to the left. It 
is about five inches long, three and a half inches transversely and two 
and a half antero posteriorly. Its weight is from nine to twelve ounces, 
varying in the two sexes and being slightly larger in the male. 
The exact position of the heart is thus stated : the base lies behind the 
sternum, corresponding to a line drawn between the upper borders of the 
extremities of the third costal cartilages; the apex is downward and to the 
left, striking the chest wall at the space between the fifth and sixth ribs, 
three to three and one-half inches to the left of the middle line, abo*ut 
opposite the gladio-xiphoid joint. 
The cavity of the heart is separated into a venous and an arterial half, 
or apartment, by an obliquely vertical septum, which cuts ofif all com- 
munication between the halves. The position of this septum can be pre- 
dicted by an inspection of the exterior of the heart, for it is marked by 
a groove passing from the base anteriorly and to the left downward to 
the right of the apex to run along the posterior aspect of the heart and 
terminate at the base, towards its right aspect. An artery is found lying 
in this groove, which is called, for a reason hereafter given, interventricu- 
lar. From the position of the groove it is seen that the apex of the The Viscera. 
141 
heart is formed entirely by the left half, the front of the heart mainly 
by the right half, while the back is the product, principally, of the left 
half. 
When the heart is laid open its entire cavity is seen to be lined by a 
serous membrane, continued into the vessels which communicate with it, 
called the endocardium, and that each lateral half is subdivided by a 
partial horizontal septum into two cavities, the upper called the auricle, 
right or venous, and left, or arterial, the lower, the ventricle, right, or 
venous and left, or arterial. 
The position of the horizontal septum is indicated by a groove passing 
around the heart called auriculo-ventricular. 
In the adult the venous blood of the entire body, with the exception 
°f that of the heart itself, is returned into the venous auricle by two great 
veins called venae cavae, superior and inferior, the one bringing the blood 
from the head and upper extremities, the other from the lower extremi- 
ties and body. The venous blood from the heart is returned to the ve- 
nous auricle by a separate vein called the coronary, which, just as it is 
about to enter the auricle, dilates into what is known as the coronary 
sinus. Besides these channels for the return of the venous blood, there 
exist numerous minute apertures in every cavity of the heart through 
which its venous blood may enter to a small extent. These are called 
foramina Thebesii. The venous blood thus collected by the venous au- 
ricle is driven by its pulsation into the venous ventricle, with which it 
communicates by an aperture through the horizontal septum called the 
venous auriculo-ventricular opening. From the venous ventricle the 
blood is sent into the pulmonary artery which soon divides into a branch 
to each lung. 
Taking up the appearances seen in the cavities of the heart, we begin 
with the venous auricle. 
The venous auricle consists of two portions; the larger part is called 
the sinus, but, communicating with this and projecting forward, is an ear- 
shaped addition, called the appendix auriculse—hence the name of the 
auricles. The sinus of the venous auricle presents the following objects : 
At its upper back part, the opening of the superior vena cava; at the 
lower back part, the opening of the inferior vena cava; between the two 
openings a slight thickening of the auricular wall called the tubercle of 
Lower; betweeen the opening for the inferior vena cava and the auriculo- 
ventricular opening is the opening for the coronary sinus, guarded by 
a valve-like fold of endocardium called the coronary valve; on the septum 
between the two auricles, an oval depression, called the fossa ovalis, and 
surrounding this, except below, a ridge called annulus ovalis; extending 142 
Notes on Anatomy. 
along the wall of the auricle from the opening of the inferior vena cava 
to the fossa ovalis, is a ridge, the remains of the Eustachian valve of 
the foetus; the lining membrane presents ridges caused by little muscular 
columns called musculi pectinati; the opening through the horizontal 
septum into the venous ventricle, and, lastly, foramina Thebesii. 
To sum up we have the following openings: ist, superior vena cava ; 
2d, inferior vena cava; 3d, coronary sinus; 4th, foramina Thebesii; sth, 
venous auriculo-ventricular; and six other appearances, viz: ist, musculi 
pectinati; 2d, tubercle of Lower; 3d, coronary valve; 4th, Eustachian 
valve; sth, fossa ovalis; 6th, annulus ovalis. 
The venous ventricle has two openings communicating with it, one for 
the pulmonary artery and the other from the venous auricle. The venous 
auriculo-ventricular opening is surrounded by an oval, fibrous ring to 
which the segments of the valve are attached. To prevent regurgitation 
of blood when the ventricle contracts, the opening is guarded by a valve 
consisting of three flaps, formed of folds of endocardium strengthened 
by fibrous tissue and some muscular fibres, which are triangular in shape 
with the base attached to the fibrous ring and the apex free. When the 
ventricle contracts the blood insinuates itself behind these flaps, which 
when the ventricle is passive, hang loosely in its cavity, and forces them 
before it until they come together, their apices meeting in the centre of 
the opening. The segments, which are quite flexible, are kept from 
being forced into the auricle by the attachment of a number of muscular 
and tendinous cords which hold them in the ventricle. The muscular 
columns are called columnse carneae and are divided into three sets ar- 
ranged as follows: some form mere ridges, being attached to the wall of 
the ventricle throughout their length; the second set are attached to the 
wall of the ventricle by each end and are free in the middle; while the 
third are attached by one end only to the ventricular wall, terminating at 
the other in tendinous cords which are themselves attached to the ventricu- 
lar aspect of the segments of the valve and are only long enough to allow 
these to close without floating into the auricle. The valve thus formed 
is known as the tricuspid, and the tendinous cords as chordae tendineae. 
The blood, driven by the contraction of the venous ventricle, is forced 
into the pulmonary artery and, when the ventricle ceases to contract, 
would again return to it were it not for a valvular arrangement here, 
called the pulmonary semilunar valve, which guards the orifice of the 
pulmonary artery. The semilunar valve is three segments arranged 
around the interior of the pulmonary artery, just at its commencement. 
Each segment is semilunar in shape, its convex border being attached 
while the superior border is free and straight. They consist of folds of The Viscera. 
143 
lining membrane, strengthened by fibrous tissue which, just at the centre 
of the free edge, is aggregated into a projection called corpus-arantii. In 
the centre the valve lacks fibrous tissue and presents a lunated space. Be- 
hind each segment there is a depression caused by a dilatation of the 
artery, called sinus of Valsalva, and when the ventricle ceases to contract 
the blood, seeking to re-enter the cavity, enters the sinuses of Valsalva 
and forces the segments together until they meet along their free edges 
and close the orifice. The corpora arantii have small effect in closing 
this orifice. 
The objects seen in the right ventricle then are: ist, columnae carneae; 
2d, chordae tendineae; 3d, venous auriculo-ventricular opening; 4th, 
opening into pulmonary artery; sth, tricuspid valve; 6th, semilunar 
valve; 7th, foramina Thebesii. 
The arterial auricle has thicker walls than the venous, being about one- 
oighth inch thick while the right is only one-twelfth inch. It presents 
musculi pectinati, which are fewer in number than in the right auricle, 
being almost confined to the appendix auriculae; the arterial auriculo- 
ventricular opening; the openings for the four pulmonary veins, which 
return the blood from the lungs. Two of these veins come from each 
lung, the two from the left sometimes uniting before entering the auricle. 
To sum up, we have ist openings for four pulmonary veins, 2d arte- 
rial auriculo-ventricular opening, 3d musculi pectinati. 
The arterial ventricle has walls three rimes as thick as those of the 
venous, being seven lines thick while the venous is only about two and a half 
lines. The left side of the heart, therefore, is much more powerful than 
the right ; this being due to the fact that while the venous ventricle has 
°nly to drive the blood into the lungs, the arterial has to send it through- 
out the entire system. On the walls of the arterial ventricle are seen 
columnse carneae, much more prominent and more intimately intersecting 
than in the venous ventricle, but similar to them in arrangement, viz: 
some attached throughout their length, some at each end and free in the 
Middle, some attached at one end to the wall of the ventricle, while* the 
others terminate in tendinous cords attached to the ventricular aspect of 
the bicuspid valve. The blood is forced from the arterial auricle into the 
arterial ventricle, and when this contracts it is forced into the aorta. 
Both these openings are guarded by valves. The valve guarding the 
arterial auriculo-ventricular opening is known as the bicuspid, or mitral, 
and is arranged upon the same principle as the tricuspid, being made up 
°f two segments attached by their bases to the fibrous ring around the 
opening while their apices are free in the cavity of the ventricle. It con- 
sists of folds of endocardium strengthened by fibrous and muscular tissue 144 
Notes on Anatomy. 
and receives the attachment of the chordae tendineae. It differs from the 
tricuspid valve in being stronger and in having only two segments. The 
opening into the aorta is guarded by the aortic semilunar valve, which is 
in every way the counterpart of the pulmonary semilunar, except in 
being larger and stronger, consist of three segments of lining membrane 
and fibrous tissue, with corpora arantii, lunated spaces and sinuses of 
Valsalva. The mechanism of their action is also the same as in the pul- 
monary semilunar. 
To sum up, there are in the arterial ventricle: ist, columnse carnese; 
2d, chordse tendineae; 3d, arterial auriculo-ventricular opening; 4th, 
aortic opening; sth, bicuspid valve; 6th aortic semilunar valve. 
The Brain. 
The chain of nervous centres, known as the cerebro-spinal axis, is 
divided into two portions, one contained in the spinal canal, called the 
spinal cord, or medulla spinalis, the other contained in the cranium and 
called the brain, or encephalon, the latter name including the membranes. 
Enveloping each of these portions, and lining its containing cavity, are 
three membranes, lying one within the other, called the investing mem- 
branes, or meninges. 
The Membranes of the Brain 
The three investing membranes of the brain are : ist, dura mater, 
lying next the cranial wall ; 2d, pia mater, lying next the brain; 3d, 
arachnoid, between these two. 
The dura mater is a grayish white, strong fibrous membrane which 
lines the inner surface of the cranial wall adhering pretty close to the 
bone, particularly at the base of the cranium and in the course of the 
sutures. Its inner surface is smooth and glistening because lined by the 
arachnoid. Besides lining the interior of the cranium, the dura mater 
gives off processes which insinuate themselves between certain portions 
of the brain. These processes, or partitions, are three in number, as 
follows; ist, the falx major, or falx cerebri, is a sickle-shaped falciform 
process of the dura mater which lies in the longitudinal fissure, attached 
in front to the crista galli and extending along the middle line to the. an- 
terior occipital protuberance behind, being continuous with the dura mater 
along the vault of the cranium between these points and separating the 
two hemispheres of the cerebrum. 
For a certain distance forward from the anterior occipital protuberance, 
corresponding in extent to the cerebellum, its lower edge is adherent to 
the upper surface of the tentoriun. The Viscera. 
145 
2d. The tentoriun cerebelli is stretched horizontally across the inferior 
occipital fossae, attached behind to the horizontal limbs of the occipital 
cross and in front to the upper border of the petrous portion of the tem- 
poral bone, on each side, and to the clinoid processes ; 3d, the falx 
minor, cerebelli, is a narrow process which separates the two lobes of the 
cerebellum; it is attached along the lower vertical limb of the occipital 
cross and forks as it approaches the foramen magnum, where it ceases. 
The arachnoid is a serous membrane and consequently a closed sac, 
one of its layers lining the inner surface of the dura mater, and called the 
parietal layer, the other investing the brain, from which it is separated by 
the pia mater, and called the visceral layer. Though it envelopes the 
brain it does not dip into the sulci but leaps from convolution to convo- 
lution. 
The pia mater is an extremely thin membrane, very vascular, consist- 
ing, in fact, of interlacing small blood vessels lying on the surface of the 
brain. It not only covers the convolutions but passes down into the 
sulci, and the space thus left between the pia mater, as it dips to the bot- 
tom of the sulci, and the arachnoid, which passes over the sulci from 
convolution to convolution, is called the sub-arachnoid space. 
The Brain. 
The brain is subdivided into four parts, viz : Cerebrum, cerebellum, 
pons varolii and medulla oblongata. 
The cerebrum, seven or eight times the size of the rest of the brain, 
presents that uneven surface called convoluted. It consists of meander- 
lng elevations, called convolutions, and corresponding depressions, an 
mch or so deep, called sulci. When examined closely these convolu- 
tions are seen not to be exactly similar on the two sides of the brain. 
The cerebrum is subdivided as follows: Upon its upper surface there 
appears a fissure extending from before backward along the centre, called 
the longitudinal fissure. This fissure, as may be seen by looking on the 
base of the brain, extends entirely through, both before and behind; but 
for the middle third of the cerebrum, it extends downwards only about 
an inch from the upper surface. The sides of the cerebrum thus separa- 
ted are called the hemispheres, right and left. 
The Base of the Brain. 
The base of the brain, that portion which presents to the floor fin- 
ished it by the base of the cranium, is composed of portions furnished 
by the four primary subdivisions and presents many points to be investi- 
gated. 146 
Notes on Anatomy. 
Beginning in front we see in the middle line the longitudinal fissure, 
and on either side of it the first cranial or olfactory nerve, which, 
emerging from the substance of the brain just at the inner end of the 
sylvian fissure, extends forward beside the longitudinal fissure, flattened, 
or somewhat triangular in shape, lying in a groove and terminating near 
the front of the brain in a dilated portion called the olfactory bulb. 
Just behind the longitudinal fissure, are seen on the front of the base, 
two nerves, the second cranial, or optic, which are united behind but 
diverge from each other forward. The union of the two, situated just 
between the olfactory nerves and just behind the longitudinal fissure, is 
called the optic chiasm, or commissure; and, diverging from this chiasm 
backward are the two flattened cords, called the optic tracts, which, after 
a short course, disappear in the substance of the brain. In the angular 
interval left on the side of the optic chiasm, between the optic nerve in 
front and the optic tract behind, there is a number of small apertures in 
the substance of the brain, made by tearing out small arteries, which 
enter here, and this appearance on either side is known as the substantia 
perforata, or anterior perforated spot. Just behind the optic chiasm, and 
between the optic tracts, is a grayish prominence called the tuber cine- 
rium; and projecting from the centre of this for about one-sixth inch, a 
small tube-like prolongation called the infundibulum, which is tipped by 
a reddish body called the pituitary gland, which weighs five to ten grains, 
is composed of an anterior and a posterior lobe and lies in the sella 
Turcica. 
Just behind the tuber cinerum are two round, white, pea-like bodies, 
one on each side the middle line, called the corpora albicantia. Behind 
these is seen a collection of apertures, just like those forming the two 
substantiae perforatae, called the locus perforatus, or posterior perforated 
spot. In the centre, just behind this is seen the broad band of transverse 
fibres called the pons Varolii, and passing forward from this, are two large 
flattened cords, diverging from each other and intersecting the optic 
tract of each side before being lost in the brain, known as the crura cere- 
bri. Between the diverging crura postero-laterally, the optic tracts antero- 
laterally, the optic chiasm in front and the anterior edge of the pons 
Varolii behind, there is a circumscribed portion of the base of the brain 
known as the six-sided, or interpeduncular space. Its boundaries are as 
above stated and it contains the following objects: ist, tuber cinerium; 
2d, infundibulum; 3d, corpora albicantia; 4th, locus perforatus. 
The Medulla Oblongata. 
Extending from the foramen magnum, or upper border of the atlas, to The Viscera. 
147 
the posterior border of the pons Varolii, is found the medulla oblongata, 
thus establishing connection between the spinal marrow and the brain. 
It is conical in shape, with the larger end above and forward, and is 
about one and one-fourth inches in length. Passing down its centre in 
front is the anterior median fissure, and similarly marking it behind 
ts the posterior median fissure; these, though not entirely bisecting 
it, serve to indicate its division into lateral symmetrical halves. Each 
half is subdivided into four portions by three longitudinal grooves. 
Lying beside the anterior median fissure, and separated by it from its 
fellow, is the portion called the corpus pyramidale; just behind this, 
slightly more bulging and separated from it by a fissure, is a second por- 
tion called the corpus olivare, being visible for about half an inch only. 
Behind this a third portion called the corpus restiforme, separated by a 
groove from the corpus olivare in front and by another slight groove 
from the fourth portion, the posterior pyramid, which lies behind the cor- 
pus restiforme, beside the posterior median fissure by which it is sepa- 
rated from its fellow. The two posterior pyramids are small below, but 
as they are followed up they suddenly dilate into a bulbous enlargement, 
and again as suddenly decreasing, separate as they ascend and leave be- 
tween them an angular interval called the calamus scriptorius—writer’s 
pen. When the medulla oblongata reaches the pons Varolii it seems on 
superficial view to stop short, but if the surface fibres of the pons, which 
are transverse in direction, are peeled off, it is seen that the pons, in its 
centre, consists of vertical, or longitudinal fibres, which are continuous 
with the fibres of the medulla oblongata below, and, being gathered into 
two bands, emerge from its anterior border as the two crura cerebri. 
SUMMARY. 
In summing up the appearances met with on the base of the brain, we 
find from before backward—ist, longitudinal fissure in the centre; 2d, 
olfactory nerve and its bulbus olfactorius; 3d, optic nerve; 4th, optic 
chiasm; sth, optic tract; 6th, substantia perforata; 7th, tuber cinerium; 
Bth, infundibulum; 9th, corpus albicans; 10th, locus perforatus; nth, 
crus cerebrii; 12th, pons Varolii; 13th, medulla oblongata. Of these 
thirteen objects, the 2d, 3d, sth, 6th, 9th and nth are double, i. e., there 
18 °ne on each side of the middle line; the others are single and are 
found on the middle line, extending on each side, more or less. 
Structure of the Cerebrum. 
When a horizontal slice an inch or so thick is removed from the upper 
surface of one hemisphere, the cut surface shows a central, oval, white 148 
Notes on Anatomy. 
portion surrounded, on the exterior, by a serrated grayish border; this is 
known as the centrum ovale minus. When both hemispheres have been 
cut to the same level, and this level corresponds to the depth of the cen- 
tral portion of the longitudinal fissure, two centra ovalia minora are pro- 
duced, connected in the centre by transverse fibres, forming a connecting 
band, called the corpus callosum; and the whole appearance, formed by 
the two centra ovalia minora and the corpus callosum, is called the cen- 
trum ovale majus. 
Corpus Callosum. 
The corpus callosum consists almost entirely of transverse fibres pass- 
ing from one hemisphere to the other. Upon its upper surface there is a 
shallow groove, extending from before backward along the middle line, 
called the raphe; bordering each side of the raphe is a slight ridge pro- 
duced by a bundle of longitudinal fibres, the two ridges being called the 
nerves of Lancisi. External to these are seen a few other longitudinal 
fibres, producing slight ridges which are called the lateral longitudinal 
strise. When the corpus callosum is bisected longitudinally it is seen to 
be about four inches long and to bend vertically downward both in front 
and behind. The bent, rounded, posterior extremity is called the sple- 
nium, or pad, or bulb, the central portion the body, and the anterior bent 
portion the genu, which turns backward beneath the body for a short 
distance under the name of the rostrum. The rostrum divides into two 
cords called peduncles, which pass downward and backward to the base 
of the brain. Contained in the substance of the brain, between its base 
and the corpus callosum, is an irregular cavity divided into several parts, 
two of which are known as the lateral ventricles, while the space is 
spoken of as the general ventricular cavity. 
Lateral Ventricle. 
The corpus callosum forms the roof of the ventricular cavity which is 
divided into two similar parts by a median septum, each part being called 
a lateral ventricle, right and left. The right ventricle is sometimes called 
the first and the left the second. When the corpus callosum has been 
removed the floor of the lateral ventricle is brought into view. It is 
formed by various objects. In front, and external, is an oblong grayish 
mass, with its large end in front, called the corpus striatum; internal to 
this, and lying against its inner aspect, is a narrow white band known as 
the tenia semicircularis, or horny band of Tarinus; just within this is seen 
a small portion of an olive shaped, white body called the optic thalamus; 
while internal to and behind this is a small bundle of blood vessels run- The Viscera. 
149 
mng from behind forward, and gathered into a round cord, called the 
choroid plexus. The choroid plexus runs along the edge of the most 
internal object seen in the ventricle, the fornix. The fornix forms the 
inner portion of the floor of each ventricle and rises to a ridge on the 
centre, which ridge touches the lower surface of the corpus callosum and 
thus forms the septum between the two ventricles. The fornix is tri- 
angular in shape, its small end, which is in front, terminating in two cords 
called the crura, which pass downward to the corpora albicantia and, 
touching their inner aspect, then ascend to the optic thalami. Behind, 
the edges of the fornix are continued towards the base of the brain in a 
tortuous course under the name of the corpora fimbriata. 
The cavity of the lateral ventricle is prolonged forward by a small tri- 
angular cavity called the anterior cornu. Posteriorly it presents a larger 
longer prolongation called the posterior cornu; and besides these two 
there is a large cavity called the middle, or descending cornu, into which 
the corpus fimbriatum disappears. The middle, or descending cornu 
begins just where the posterior cornu joins the body of the ventricle, and 
its direction is tortuously downward. It first runs outward and back- 
ward, then downward, forward and inward. The objects seen in it are 
as follows: Mounting up through it is the bundle of blood vessels, called 
the choroid plexus, these vessels having entered the bottom of the cornu. 
The corpus fimbriatum, the continuation of the posterior angle of the 
fornix disappears as a white band which follows the course of the cornu 
to the base of the brain. In this cornu is seen a ridge which, following 
the course of the cornu terminates at its bottom in an enlargment called 
the pes hippocampi, the ridge itself being called the hippocampus major. 
Just where the descending and posterior cornua communicate with the 
body of the ventricle, there is a projection between the two cornua called 
the pes accessorius, to which the hippocampus major leads, from the de- 
scending cornu, and to which a similar but smaller ridge, the hippocam- 
pus minor, seen on the bottom of the posterior cornu, also leads. The 
septum between the two lateral ventricles is the ridged centre of the for- 
nix5 but since the fornix is too short to reach to the anterior extremity 
°f the ventricle, the septum between the two ventricles is completed in 
front for a short distance by a double-layered membrane called the sep- 
tum lucidum, between the two layers of which membrane there is a mi- 
uute interval, called the fifth ventricle. 
After examining the lateral ventricle we cut away the fornix and 
choroid plexuses and expose just beneath them, another cavity called the 
third ventricle. This cavity lies between the optic thalami which form 
lts sides. Its floor corresponds to the six sided space at the base of the 150 
Notes on Anatomy. 
brain; its roof was the fornix; its anterior boundary a white band pass- 
ing between the two corpora striata called the anterior commissure; its 
posterior boundary another white band, passing between the optic thalami, 
called the posterior commissure. Crossing the centre of the cavity, also 
between the optic thalami, is a third band called the soft commissure. 
The space in front of the soft commissure is sometimes called the fora- 
men commune anterius, and that behind the foramen commune posterius. 
In this ventricle four openings may be seen, viz: ist, on the front of 
the floor is a canal which leads to the infundibulum—iter ad infundibu- 
lum; 2d, on the front of the roof are two small openings, one on each 
side of the middle line, the foramen of Munro, which exists for the pur- 
pose of allowing the choroid plexuses to pass from the lateral ventricles 
to the third ventricle. 
The choroid plexus of each lateral ventricle, as has been seen, consists 
of a rounded mass of small arteries which perforate the bottom of the 
middle cornu, pass upward through the descending cornu, collecting 
into a bundle, which runs forward beside the fornix and, reaching 
its anterior extremity, disappears by notching the edge of the fornix 
and enters the third ventricle, where it meets its fellow on the 
lower surface of the fornix and the two immediately spread out so as to 
form a membrane-like layer of vessels which covers the lower surface of 
the fornix and forms the true roof of the third ventricle. This layer is 
known as the velum interpositum. The fourth opening into the third 
ventricle is seen behind, just beneath the posterior commissure, and leads 
backwards and downwards to another cavity called the fourth ventricle, 
which is found between the cerebellum and the medulla oblongata. The 
communication between the third and fourth ventricles is called the 
aqueduct of Sylvius—iter a tertio ad quartum ventriculum. Dissecting 
up the optic thalami we see on the lower surface of each, posteriorly, 
two small oblong bodies, one lying internal to the other and separated 
by the optic tract which passes between them. The outer of these bodies 
is called the corpus geniculatum externum, the inner, the corpus genicu- 
latum internum. Immediately behind the third ventricle, over the aque- 
duct of Sylvius and beneath the bulb of the corpus callosum, there are 
two pairs of elevations collectively called the corpora quadrigemina. 
These elevations are arranged as follows: two in front, one on each side 
of the middle line, called the nates; and two behind, one on each side of 
the middle line, called the testes. Passing outward and forward to the 
optic thalamus from each side of the corpora quadrigemina are two bands, 
or ridges, one from the nates, called brachium anterius, and one from the 
testes, called brachium posterius. Lying between the nates is a small, The Viscera, 
151 
conical, reddish projection called the pineal gland, which has a cavity in 
its interior containing a little viscid fluid and a small quantity of gritty 
matter. It is held in place by four peduncles, or cords, two passing 
downward from the base of the gland to the optic thalami; and two pass- 
ing forward, one on each side of the middle line, skirting the inner aspect 
of the optic thalami, along the lateral wall of the third ventricle, to the 
crura of the fornix. 
Convolutions of the Cerebrum. 
In studying the convolutions we begin with the principal fissures of 
which there are five, viz; ist, the great longitudinal fissure, separating 
the two hemispheres; 2d, the great transverse fissure of Bichat, between 
the cerebrum and cerebellum, which admits the pia mater into the interior 
of the brain; 3d, the fissure of Sylvius; 4th, the fissure of Rolando; sth, 
the parieto-occipital fissure. 
The fissure of Sylvius begins at the anterior perforated space and 
passes outward to the external surface of the hemisphere and divides into 
two branches; one, passing upward towards the longitudinal fissure, is 
termed the ascending limb ; the other, running nearly backward, the 
horizontal limb. 
The fissure of Rolando, situated about the middle of the outer surface 
of the hemisphere, begins near the longitudinal fissure and runs down- 
ward and forward to terminate just above the horizontal limb of the 
fissure of Sylvius. It forms a knee-like bend in its course. 
The parieto-occipital fissure is seen but slightly on the outer surface of 
the hemisphere. It serves to separate the parietal and occipital lobes 
and is distinctly marked on the internal face of the hemisphere. 
By these fissure the hemisphere is divided into five lobes—frontal, 
Parietal, occipital, temporo-sphenoidal and the central, or island of Reil. 
The frontal lobe is situated in front of the fissure of Rolando and above 
the fissure of Sylvius. Its lower surface rests on the orbital plate of the 
frontal bone. 
The parietal lobe is bounded in front by the fissure of Rolando, behind 
hy the parieto-occipital fissure and below by the horizontal limb of the 
fissure of Sylvius, which separates it from the temporo-sphenoidal lobe. 
The occipital lobe is situated at the posterior extremity of the brain, 
separated from the parietal, partially, by the external part of the parieto- 
°ccipital fissure, while below its convolutions pass directly into the tem- 
poro-sphenoidal lobe. 152 
Notes on Anatomy. 
The temporo-sphenoidal lobe is lodged in the middle fossa of the skull. 
It is limited in front and above by the fissure of Sylvius; behind it is 
connected with the parietal and occipital lobes by connecting convolu- 
tions. 
The island of Reil is situated in the fissure of Sylvius at the base of 
the brain, hidden under the fused lower ends of the ascending frontal 
and parietal convolutions, known as the operculum. 
Convolutions. 
The precentral, or vertical fissure runs upward through the frontal 
lobe, cutting off a convolution, which lies between it and the fissure of 
Rolando, called the ascending frontal convolution. The ascending parie- 
tal and ascending frontal convolutions are continuous around the lower 
end of the fissure of Rolando. The remainder of the outer surface of 
this lobe is divided into three convolutions by two antero-posterior sulci, 
called first and second frontal sulci. The convolutions thus cut off are 
known as first, second and third frontal convolutions, numbered from 
above downward, and are continuous with the convolutions on the orbi- 
tal or lower surface, which are marked off by two sulci, the most internal 
of which is the groove for the olfactory nerve. 
The parietal lobe presents an ascending parietal convolution, corre- 
sponding to the ascending frontal, which is limited in front by the fissure 
of Rolando and behind by the interparietal fissure. The interparietal 
fissure first ascends just behind the fissure of Rolando and then runs 
backward and cuts off a convolution which borders the longitudinal fissure 
and is called the superior parietal convolution. The remainder of this 
lobe is divided into two convolutions by a vertical fissure, the convolution 
in front being called the supra-marginal and that behind the angular. 
The latter is joined to the temporo-sphenoidal and occipital lobes by 
small connecting convolutions. 
The occipital lobe is imperfectly divided, by two small, transverse 
fissures, into three convolutions, numbered from above downward and 
called first, second and third occipital convolutions. 
The temporo-sphenoidal lobe has on its outer surface three convolu- 
tions, cut off by two antero-posterior fissures, numbered from above 
downward and called first, second and third temporo-sphenoidal con- 
volutions ; while on its lower surface are two more, divided from each 
other by the occipito-temporal, or collateral sulcus. They are the fusi- 
form and lingual lobules. 
On the inner surface of the hemisphere the convolutions are not con- The Viscera. 
153 
fined to lobes and are less complex. There are five fissures, the calloso- 
marginal, parieto-occipital, calcarine, collateral and dentate. 
The calloso-marginal sulcus begins beneath the rostrum of the corpus 
callosum, winds around its genu, runs backward parallel with its body 
about half the length of the hemisphere and then turns upward to reach 
the margin of the hemisphere near the fissure of Rolando. 
The parieto-occipital fissure extends downward and forward to join the 
calcarine fissure, just behind the body of the corpus callosum. 
The calcarine fissure commences by two branches at the back of the 
hemisphere, runs nearly horizontally forward and is joined by the pa- 
rieto-occipital fissure and continued forward as far as the posterior infe- 
rior extremity of the gyrus fornicatus. 
The collateral, or occipito-temporal fissure runs forward from the pos- 
terior extremity of the brain nearly as far as the commencement of the 
fis sure of Sylvius. 
The dentate fissure, or sulcus hippocampi commences below the poste- 
rior extremity of the corpus callosum, and runs forward to terminate at 
the recurved part, or hook of the uncinate gyrus. 
The convolutions marked off by these fissures are the gyrus fornicatus, 
marginal, quadrate, cuneate, uncinate and temporo-sphenoidal. 
The gyrus fornicatus begins near the anterior perforated space, wind 
around the genu of the corpus callosum, passes along its body, winds 
around its bulb, under the name of the gyrus hippocampi and terminates 
as the uncinate gyrus nearly where it begins. 
The marginal is the inner aspect of the first frontal convolution. It 
commences at the anterior perforated space, runs along the margin of the 
longitudinal fissure, on the orbital surface of the frontal lobe, bounded 
externally by the sulcus for the olfactory nerve, turns upward to the 
upper surface of the hemisphere and ceases where the calloso-marginal 
sulcus reaches the upper surface of the hemisphere. If, is separated by 
this sulcus from the gyrus fornicatus. 
The quadrate lobule, or precuneus, lies between the calloso-marginal 
fissure in front and the parieto-occipito behind. 
The cuneus is situated between the parieto-occipital and calcarine 
fissures and is triangular in shape. 
The uncinate gyrus is the anterior inferior termination of the gyrus 
fornicatus, with which it is connected by the gyrus hippocampi. It ex- 
tends as far as the fissure of Sylvius and is bounded above by the den- 
tate fissure and below by the collateral fissure which separates it from the 
temporo-sphenoidal lobe. 
The convolutions of the temporo-sphenoidal lobe have been described. 154 
Notes on Anatomy. 
The Cerebellum. 
The cerebellum is only one-eighth the size of the cerebrum and is found 
in the inferior occipital fossae, lying beneath the occipital lobes of the cere- 
brum, from which it is separated by the tentorium. The appearance of 
its surface differs from that of the cerebrum in not being convoluted, but 
is marked by numerous more or less curved furrows or sulci between 
which are plate-like parts of the brain substance called laminae, hence 
the surface is said to be laminated. It is oblong in shape, its greatest 
diameter, which is the transverse, measuring four inches. It is divided 
into two hemispheres by a ridge above, called the vermis superior, 
which extends along the middle line from a notch in the anterior edge, 
called incisura anterior, to another notch in the centre of the posterior 
border, called incisura posterior. On the lower aspect the two hemis- 
pheres are separated, or rather the separation is indicated, by a groove, 
broad and shallow, extending from the anterior to the posterior notch 
and called the valley. Running along the bottom of this groove is 
another ridge, called vermis inferior. 
When a vertical antero-posterior section of either hemisphere is made 
an appearance is produced, called arbor vitae, which resembles the trunk 
of a tree with some ten or twelve branches. The trunk is white and 
placed horizontally in front; the branches, which are also white, diverge 
from the trunk superiorly, inferiorly and posteriorly. The surrounding 
substance is gray. A little above and behind the centre of the trunk is 
an irregular mass of gray matter, called the corpus dentatum. 
Beneath the cerebellum, between it and the posterior aspect of the 
medulla oblongata, is the fourth ventricle. It is lozonge-shaped—tri- 
angular in vertical section—and its boundaries are as follows: Its floor is 
the calamus scriptorius of the medulla; its roof is formed by two ele- 
ments, the lower, posterior part is the cerebellum ; the front part is the 
membrane like layer, called the valve of the brain, or valve of Vieussens; 
each side is formed by a thick cord passing from the cerebellum to the 
testes and called processus e cerebello ad testes. The ventricle is closed 
behind and below by a fold of pia mater as it passes from the medulla to 
the cerebellum. 
On the floor of the ventricle are two rounded oblong ridges called fas- 
ciculi teretes. Crossing these, as they are passing from the posterior 
median fissure outward, are the fibres of origin of the eighth, or audi- 
tory nerve; these fibres, being white and running transversely, are called 
lineae transversae. On that portion of the roof formed by the cerebellum 
there are four projections, one in front, on the middle line, called the mo- The Viscera, 
155 
dulus, one just behind this called the uvula and one each side of the 
uvula, called amygdala or tonsil. Communicating with the front upper 
extremity of the ventricle is the aqueduct of Sylvius, which passes up- 
ward and forward beneath the corpora quadrigemina to the back part of 
the third ventricle. The fourth ventricle was called by the older anato- 
mists the first, since it was more easily reached and more constant in its 
existence in the different natural orders. 
The different parts of the brain are connected, generally by white 
fibres, in order to harmonize the action of the different parts. The two 
hemispheres of the cerebrum and their subdivisions, are connected across 
the middle line by—ist, the corpus callosum; 2d, the anterior commis- 
sure ; 3d, the middle commissure; 4th, the posterior commissure. The 
different parts of the same hemisphere are connected by white fibres 
which pass from before backward, as the crura of the fornix, the toenia 
semicircularis, the brachium anterius, brachium posterius, &c. 
The two hemispheres of the cerebellum are connected by the vermis 
superior and inferior, by the transverse fibres of the pons Varolii, which, 
leaving the anterior part of one hemisphere under the name of crus cere- 
belli, a thick white cord, pass across, forming the transverse fibres of the 
pons, and enter the other hemisphere as the other crus. 
The two sides of the medulla oblongata are connected by a central 
commissure, like the spinal cord, and by a decussation of the anterior 
pyramids across the anterior median fissure. 
The cerebellum is connected to the cerebrum by the two processus e 
cerebello ad testes. The medulla is connected to the cerebellum by the 
corpora restiformia which pass to it as processus ad medullam oblongatam. 
It is connected to each hemisphere of the cerebrum by one of the two 
crura cerebri which, as has has been seen, form the longitudinal fibres of 
the pons and emerge from it to reach the cerebrum. 156 
Notes on Anatomy. 
THE ORGAN OF HEARING. 
The organ of hearing is connected with the temporal bone of each 
side, and properly speaking, consists of two organs, one to each side. 
In the prepared bone a portion is still preserved, for upon the base of the 
petrous portion of the temporal bone the bony portion of the external 
auditory meatus is seen; and on the posterior surface of the petrous por- 
tion the internal auditory meatus, at the bottom of which is seen the inter- 
nal wall of the inner chamber perforated by numerous apertures. The ex- 
ternal wall of the inner chamber is seen by looking into the external 
auditory meatus. On the anterior face of the petrous portion are seen 
the bulge of the superior semicircular canal and just external to this a 
depression corresponding to the roof of the middle chamber, or tympa- 
num, the floor of which is the jugular fossa, on the basilar face of the 
petrous portion of the temporal. 
The organ of hearing is described as consisting of three portions, or 
chambers, lying the one internal to the other, upon the base and in the 
substance of the petrous portion of the temporal bone. These three 
chambers are known from without inward as—ist, external ear consisting 
of three portions, (a) pinna, or auricle; (b) meatus auditorius externus; 
(c) membrana tympani; 2d, middle ear or tympanum; 3d, internal ear, 
or labyrinth. 
The External Ear 
The external ear consists of three portions named above. Its func- 
tion is to connect the sonorous vibrations and convey them to the middle 
ear, which in turn transmits them to the internal ear, where they en- 
counter the sentient nerve of hearing. 
The pinna, or auricle is the expanded outer extremity of the external 
chamber found on the base of the petrous portion of the temporal bone, 
contracting to its termination in the external auditory meatus. It pre- 
sents a very uneven surface and the various elevations and depressions 
have received individual names. The central concavity, leading to the 
external auditory meatus, is called the concha; the more or less folded 
margin, or rim, the helix; the pendant, lower, softer portion, the lobulus; 
the triangular prominence jutting out in front of the concha, the tragus; 
behind and somewhat below this separated from it by a notch, is another 
projection, the antitragus; the curved elevation between the helix and 
the concha, or rather behind the concha, is the anti-helix, which divides 
superiorly enclosing a depression called the fossa ovalis; the deeply The Organ of Hearing 
157 
sunken surface between the helix and the anti-helix is the fossa scap 
hoidea, or innominata. 
The pinna varies greatly in different people, and this is especially true 
of the lobule. In structure it consists of a plate of fibro-cartilage, whose 
folds produce the depressions and elevations mentioned. This cartilage 
is covered by integument and alveolar tissue, supporting various insignifi- 
cant muscles, intrinsic, intended to vary its shape, and giving attachment 
to other small muscles, extrinsic, intended to move the pinna. Of the 
latter some few people have use, but the former never act to produce 
visible effect. The cartilage is not continuous throughout the auricle, 
for it is altogether wanting in the lobule and, besides, presents several 
fissures which have received names. The pinna is held in position by 
the integument, by the extrinsic muscles mentioned above and by two 
ligaments, anterior and posterior. The anterior extends from the helix 
to the zygoma; the posterior, from the concha to the mastoid process. 
Besides these there are several small ligaments passing from one part of 
the cartilage to another, the largest of which is that between the tragus 
and helix. 
The external auditory meatus is the canal which extends from the con- 
cha to the tympanum, from which it is separated by the tympanic mem- 
brane. It is rather more than an inch in length, its direction being 
inward and slightly forward and its course somewhat curved, with its 
convexity upward. It is smaller in the centre than at either end. It 
consists of an external cartilaginous portion, taking up one-third of its 
length, and an internal, osseous portion, taking the remaining two-thirds. 
The osseous portion terminates internally at an oblique groove for the 
attachment of the membrana tympani. This portion can be seen in the 
dried bone, although the septum in the bottom is of course absent. The 
outer extremity is rough and prominent for the attachment of the carti- 
laginous portion. It is lined throughout by the integument which, to- 
ward the exterior, is studded with hairs and contains glands for the se- 
cretion of the ear wax. The hairs and wax are intended to obstruct the 
entrance of insects, &c. 
The membrana tympani is the septum separating the external from the 
middle chamber, being situated at the inner extremity of the external 
auditory meatus, attached to the oblique groove there found. It is fra- 
gile, semi-transparent, nearly round, oblique in its direction from above 
downward and inward, striking the floor at an angle of 450, and is seen 
to bulge toward the tympanum, having a corresponding concavity ex- 
ternally. Its frame work is fibro-elastic, consisting of radiating and con- 
centric fibres, the latter especially seen near its circumference; it is 158 
Notes on Anatomy. 
covered externally by the integument lining the external auditory meatus, 
which is exceedingly sensitive. Internally it is coated by the mucous 
membrane of the tympanum. 
The Middle Ear. 
The middle ear, chamber, or tympanum, lies in the petrous portion of 
the temporal bone, separated, externally, from the meatus auditorius ex- 
ternus by the membrana tympani; and separated, internally, from the 
inner chamber, or labyrinth by a bony wall and its roof corresponds to 
the depression on the anterior face of the petrous bone, its floor to the 
jugular fossa on the basilar face of that bone. Its anterior wall is a bony 
partition interposed between it and the internal carotid artery and its 
posterior wall is the cellular substance of the mastoid portion of the tem- 
poral bone. Owing to the obliquity of the inner and outer walls, the 
tympanum is much narrower transversely, below than above. The length 
of its roof from without inward is about three lines, the floor being 
scarcely more than one line. It presents for examination six walls, two 
of which—floor and roof—have nothing noteworty. The outer wall has 
been described as the membrana tympani, having attached to it a chain 
of bones, which extends to the inner wall. 
The internal wall is the bony partition between the tympanum and the 
labyrinth, upon which are seen the following appearances: (a) a ridge 
at its upper part corresponding to the aqueduct of Fallopius; (b) just be- 
neath this a kidney-shaped aperture, opening into one of the apartments 
of the labyrinth, called the fenestra ovalis. This is closed during life by 
a membrane to which is attached the foot of the stapes; (f) below this is a 
bulging surface known as the promontory; (d) beneath this is a second 
opening oval, or triangular in shape, called the fenestra rotunda, which 
is likewise closed by a membrane and establishes communication with 
another part of the labyrinth called the cochlea. 
The posterior wall presents several small openings into the mastoid cells 
and the opening for the entrance of the chorda tympani, iter chordae pos- 
terius, which crosses the tympanum to gain exit on its anterior wall. 
There is also a conical projection, the pyramid, which has at its summit 
an opening for the stapedius muscle. 
On the anterior wall are seen: (a) the fissure of Glaser; (55) the open- 
ing of exit of the chorda tympani, iter chordae anterius, or canal of Hu- 
guier; fc) twro small openings, separated by a thin plate of bone, the 
upper called the opening for the tensor tympani, the lower the opening 
for the Eustachian tube, and the dividing septum the cochleariform pro- 
cess, Stretching across the tympanum from the membrana tympani, The Organ of Hearing. 
159 
externally, to the fenestra ovalis internally are seen three small bones, 
malleus, incus and stapes. The malleus is the outermost of the three, 
resting against the membrana tympani externally and articulating with 
the incus internally. It consists of a head, for articulation with the incus, 
a neck and three processes. One of the processes is called the handle, 
manubrium, and lies embedded in the membrana tympani, half way to 
the floor from above downward. Another, the long process, processus 
gracilis, passes downward to the fissure of Glaser; while the third, the 
short process, bulges outward from the neck. The incus is so called from 
its resemblance to an anvil. It consists of a body, for articulation with 
the head of the malleus, and two processes. The short process passes 
backward to the opening of the mastoid cells in the posterior wall; the 
long, passes downward to articulate with the head of the stapes, termi- 
nating in an enlargement, called the os orbiculare. The stapes, stirrup, 
projects inward from the os orbiculare, with which it articulates by a 
head. Succeeding the head comes the neck and diverging from this are 
the two crura, one to either side, which are connected at their distal ex- 
tremity by a plate, called the foot, which is exactly fitted into the fenestra 
ovalis. When the child is born those bones have attained nearly their 
full size. They are held together by ligaments and give attachment to 
several small muscles which are intended to move the bones on one 
another and thus relax, or tighten the membrana tympani, or the mem- 
brane of the fenestra ovalis. This latter membrane is in fact composed 
of two layers, and the fenestra ovalis is closed successively by the follow- 
ing parts from without inward, viz; ist, the raucous membrane of the 
tympanum; 2d, beneath this the foot of the stirrup; 3d, on the labyrin- 
thine surface this foot is coated by the serous membrane lining the laby- 
rinth. The arrangement for closing the fenestra rotunda is similar in 
consisting of three elements; (ist), a fibrous membrane coated by (2d) 
the mucous membrane of the tympanum externally and (3d) internally 
by the serous membrane of the labyrinth. It is constructed so much 
like the membrana tympani that it has been called the membrana tym- 
pani secundaria. The ossicula auditus are held to one another and in 
position by means of small ligaments. The head of the malleus is held 
to the body of the incus by a capsular ligament; and another capsular 
ligament binds together the os orbicularis and the head of the stapes. 
The ligaments holding the bones together are three in number; ist, the 
foot of the stapes is held to the fenestra ovalis by means of ligamentous 
fibres; 2d, there is a suspensory ligament of the malleus consisting of a 
few ligamentous fibres passing between its head and the roof of the tym- 
panum; 3d, a band of fibres attaches the short process of the incus to 160 
Notes on Anatomy. 
the opening of the mastoid ceils. These bones, thus permitted motion 
by means of the ligaments, are moved not only by the vibrations of the 
membrana tympani but by two small muscles, viz: The tensor tympani 
which springs from the apex of the basilar surface of the petrous bone 
and the upper aspect of the cartilaginous portion of the Eustachian tube 
and enters the opening in the tympanum known by its name, and found 
just above the processus cochleariformis, which separates it from the 
opening of the Eustachian tube; it also derives a few fibres from the 
canal it traverses. When it reaches the anterior wall of the tympanum 
its tendon turns outward and is inserted into the malleus at the junction 
of the manubrium and long process of the malleus. The stapedius is 
far the smallest muscle in the body. It arises within the hollow pyramid, 
on the posterior wall of the tympanum, emerges from the opening on 
the summit of the pyramid and is inserted by a tendon into the neck of 
the stapes. The action of the stapedius is to regulate the pressure of the 
foot of the stapes against the fenestra ovalis. 
The Eustachian Tube. 
The Eustachian tube is a canal, which establishes communication be- 
tween the air in the tympanum and the outside atmosphere. It passes 
from the anterior wall of the tympanum, where its opening is seen just 
beneath the processus cochleariformis, downward, forward and inward, to 
terminate in the pharynx, just behind the opening of the posterior nares,. 
Its lowrer third is cartilaginous; its upper two-thirds osseous. 
The Internal Ear. 
The internal ear, or labyrinth is the innermost of the three chambers, 
which constitute the organ of hearing and is intended for the terminal 
ramifications of the auditory nerve, which reaches it through the internal 
auditory meatus, on the centre of the posterior face of the petrous bone, 
and for the reception of the communicated vibrations of air, which reach 
it through the tympanum. It consists of an osseous and a membranous 
labyrinth, the osseous being divided into three chambers, which, how- 
ever, communicate with one another. These three parts are placed one 
behind the other: the anterior is called the cochlea, the middle the vesti- 
bule, the posterior the three semicircular canals. They are all lined by a 
serous coat. 
The Vestibule. 
The vestibule is a three cornered cavity, having communication with the 
tympanum through the fenestra ovalis. Each corner is called a ventricle The Organ of Hearing. 
161 
and the three are known as anterior, superior and posterior. In the an- 
terior are seen the following- objects • ist, a depression, called fovea hem- 
ispherica; 2d, a number of minute apertures, called the macula cribrosa; 
3d, a ridge, the eminentia pyramidalis ; 4th, the opening into the coch- 
lea, scala vestibule. In the superior we have: ist, a depression—the 
fovea hemi-elliptica; 2d, the two openings of semicircular canals—the 
dilated extremities of the superior and horizontal. The posterior pre- 
sents : ist, a depression—fovea sulciformis; 2d, the opening of the aque- 
duct of the vestibule; 3d, the dilated extremity of the oblique semicir- 
cular canal, the common aperture for this canal and the superior and the 
opening of the horizontal canal. 
The Semicircular Canals. 
These canals are channels hollowed in the petrous portion of the tem- 
poral bone. They are three in number, each about one-twentieth of an 
inch in diameter, and placed at right angles to one another. Each forms 
rather more than a semicircle and presents near one extremity an enlarge- 
ment, called the ampulla, and opens by both ends into the vestibule. 
The three canals are called: ist, superior, which is vertical in direction 
and produces the ridge seen on the anterior face of the petrous bone; 2d, 
the posterior, or oblique, which is also vertical; 3d, the external, or hori- 
zontal. These three canals present but five openings into the vestibule, 
owing to the fact that the posterior and superior have a common opening 
into the posterior corner of the vestibule. The other openings were 
mentioned in the description of the vestibule—three being into the pos- 
erior and two into the superior corner. 
The Cochlea. 
The cochlea lies in front of the vestibule and by its base forms the 
promontory, seen on the inner wall of the tympanum. When entire it 
resembles a snail’s shell and may be described as consisting of a tube 
divided into two apartments by a longitudinal septum, one end of the 
tube being closed and much smaller than the open end from which it 
rapidly tapers. The septum is not complete, for it fails to reach to the 
small, closed end, thus allowing a communication between the two cham- 
bers, This tube is coiled by two turns and a half around a stem, or 
tapering pillar, called the modiolus. The septum subdividing the two 
chambers, which are called scalae, is named the lamina spiralis. It con- 
sists of two layers, between which is a narrow space, called scala media, 162 
Notes on Anatomy. 
and it terminates in a hook-like projection, called the hamulus. When 
examined closely the lamina spiralis is seen to consist of three structures: 
the portion next the modiolus is bony, farther out it is membranous and 
the outermost portion is muscular and sometimes called the cochlearis 
muscle. The small space, existing between the extremity of the lamina 
spiralis and the cupola, is called the helicotrema; it establishes communi- 
cation between the two chambers, one of which is called the scala tym- 
pani, the other the scala vestibuli. The scala vestibuli is seen to com- 
municate, at the base of the cochlea, next the vestibule, with the anterior 
corner of the vestibule. The scala tympani communicates with the tym- 
panum, by means of the fenestra rotunda. The modiolus is the tapering 
pillar around which the two scalse wind. In its centre there is a canal 
called the tubulus centralis modioli. Its base is next the vestibule. 
The Membranous Labyrinth. 
Besides the parts above described, the labyrinth contains others, for 
within each semicircular canal is a membranous counter part, two-thirds 
smaller, separated from the bony wall by liquid. The membranous canals 
present the same dilations at one end, ampulla, as the bony. 
In the vestibule also are two membranous sacs, one above the other. 
The upper one receives the openings of all the semicircular canals and 
lies in the fovea hemi-elliptica. It is called utriculus, or sacculus pro- 
prius. In the membranous labyrinth, as the above parts are collectively 
called, are found crystalline particles, carbonate and phosphate of lime, 
called ear-dust, or otoliths. 
The auditory nerve gains the labyrinth through the internal auditory 
meatus. At the bottom it divides into a vestibular and a cochlear branch, 
the latter dividing into filaments which run in channels in the modiolus 
and turn outward to ramify in the lamina spiralis. The vestibular branch 
divides into three, one for each of the membranous sacs, and one for the 
semicircular canals. The Organ of Vision. 
163 
THE ORGAN OF VISION. 
The organ of vision is situated in the orbits, two conical cavities found 
on the face. Like the organ of hearing, it consists of two similar por- 
tions, one on each side, called the eye-ball and its appendages. 
The Appendages of the Eye. 
The appendages of the eye, tutamina oculi, are mere accessories to the 
true organ of vision, the eye-ball, for the purpose of protection and orna- 
ment. They are; 
I. Eyebrow is a prominence of the integument, curved, covered with 
hair and situated above each orbit. They are intended for ornament and 
protection from dust, perspiration and too vivid light, and to break the 
force of any blow falling on the front of the orbit. 
11. The eyelids consist of two movable curtains, which are constantly 
playing over the front of the eye-ball. The aperture, which separates 
the two lids, one called upper, superior palpebra, the other lower, inferior 
palpebra, is known as the palpebral fissure and can be extinguished, or 
dilated at pleasure. The two lids meet externally at an acute angle called 
the external canthus; internally when they seem about to meet they refrain 
from doing so and the interval between is prolonged inward towards the 
nose for some distance before forming the internal canthus. The trian- 
gular space thus left between the lids at the inner canthus is called the 
lachrymal lake, lacus lachrymalis, in which is seen a reddish, conical 
projection, called the caruncle, which is bounded externally by a curved 
fold of mucous membrane, called the plica semicircularis. The concavity 
of this fold is external. 
At the commencement of the lachrymal lake, just where the two lids 
are apparently about to unite, there is a projection from the edge of each 
lid, called the lachrymal papilla, or tubercle, on the summit of each of 
which is an opening, the punctum lachrymale. The free edge of each 
lid is provided with several rows of short curved hairs, the eye-lashes, 
mtended for ornament, to render the contact of the lids more intimate 
and to protect against dust, etc. In structure the eye-lids consist of the 
following parts: externally there is a layer of thin, loose skin with subja- 
cent areolar tissue; internally, a layer of mucous membrane called the 
conjunctiva, which not only lines the inner surface of the lids, but is 
reflected over the front of the ball—palpebral and ocular portions. The 164 
Notes on Anatomy. 
palpebral portion is studded with papilla. Just beneath the integument, 
on the outer surface of the lid, is a pale thin muscle, the orbicularis pal- 
pebrarum, so named from the fact that it is somewhat round, passes from 
one lid to the other and surrounds the palpebral fissure, its function is to 
close the lids. Beneath the orbicularis palpebrarum, in each lid, is a 
curved plate of cartilage, about an inch in length, called the tarsal carti- 
lage. The superior is the larger and is semilunar in shape; the inferior 
is much the narrower and oval. The two are attached along their cir- 
cumference to the edge of the orbit by ligamentous fibres. Externally, 
they are held to the outer angle of the orbit by a ligament called the ex- 
ternal palpebral, or tarsal ligament; internally, they terminate in a liga- 
ment, called the tendo oculi, which holds them to the edge of the orbit. 
Lying on the posterior surface of the lids between them and the mucous 
membrane, and opening on the edge of the lids is a number of vertical, 
beaded bodies, the Meibomian glands, the secretion from which is dis- 
charged on the edge of the lids. There are thirty of these glands for the 
upper lid, but a smaller number for the lower. 
111. Lachrymal apparatus. Lying in the depression, seen on the 
orbital plate of the frontal bone, just behind the external angular process, 
is the lachrymal gland. It is about the size and shape of an almond and 
rests on the posterior part of the upper tarsal cartilage. The ducts, seven 
to twelve in number, which convey the secretion of the gland, tears, 
being discharged on the surface of the conjunctiva, is constantly swept 
toward the inner canthus of the eye by the frequent movement of the 
lid; there it disappears in the lachrymal puncta from each of which there 
leads a small canal called the lachrymal canaliculi. The upper first as- 
cends then bends inward to terminate in the nasal, or lachrymal duct; 
the lower first descends, then turns inward to terminate in the nasal duct 
.beside the superior. The nasal duct extends a little way above the 
openings of the canaliculi in a portion, called the lachrymal sac; and from 
this point the duct extends downward, outward and slightly backward to 
terminate in the inferior meatus of the nose. 
The Globe of the Eye. 
The eye-ball is situated in the front part of the orbit, embedded in a 
mass of fat. It is nearly globular, its antero-posterior diameter being 
one inch and its transverse seven-twelfths of an inch. Posteriorly it re- 
ceives the optic nerve, at a point about one one-tenth of an inch to 
the nasal side of the centre. The ball consists of concentric layers en- The Organ of Vision. 
165 
closing a bag of liquid, which forms about four-fifths of it. These coats 
or layers are sclerotic, choroid and retina. 
The Sclerotic Coat. 
The sclerotic, familiarly known as the white of the eye, is a dense 
fibrous membrane, which serves as a protecting envelope for the rest of 
the eye-ball. Its anterior one-sixth is wanting, the aperture being filled 
by a transparent membrane, the cornea. Posteriorly the sclerotic is per- 
forated by the optic nerve, not en masse, for the nerve splits into a num- 
ber of fibres, which pierce the coat separately, producing the appearance 
known as macula, or lamina cribrosa, the fibrous sheath of the nerve be- 
coming continuous with the sclerotic, while in front the sclerotic is con- 
tinuous with the cornea. 
The Cornea. 
The cornea forms the anterior one-sixth of the first investment of the 
eye-ball. It forms a segment of a smaller sphere than the sclerotic and 
being more convex it causes the increase of the antero-posterior diameter 
over the transverse. The cornea, instead of being opaque, like the 
sclerotic, is transparent and its circumference is received beneath the an- 
terior bevelled edge of the sclerotic with which it is continuous in some 
of the structures. It consists of five layers. The anterior surface is an 
epithelial layer, derived from the conjunctiva; the posterior layer is also 
epithelial, the lining membrane of the anterior chamber. Next each of 
these is found a layer of elastic tissue, the two layers constituting what 
is called the elastic cornea, and separating these is a layer of fibrous tis- 
sue, called the cornea propria, which can be split into sixty layers of 
spindle-shaped cells with branching intervals, in which circulates the 
colorless plasma of the blood. It is with this cornea propria that the 
sclerotic is continuous. The cornea is of varying convexity in different 
people and at different periods of life. It is more convex in youth and 
becomes less so in old age, at which period there is often seen around 
the cornea a yellowish band, called arcus senilis. 
The Choroid. 
The choroid lies within the sclerotic, with which it is connected by 
areolar tissue, sometimes called lamina fusca, which is pierced by the 
optic nerve. At the point in front where the sclerotic ceases the choroid 
terminates in a flattened membrane, the iris, which, in its centre presents 
a round aperture, the pupil. The choroid consists of three layers, the 166 
Notes on Anatomy. 
outer two red and the inner black. Between the two red and the black 
layers some make a fourth layer, the membrana limitans. The external 
red layer is called the venous layer; the internal red layer the capillary, 
arterial, layer, or the tunica Ruyschiana. The internal layer, or mem- 
brana pigmenti, or tapeta is of a black color, consisting of cells, filled 
with coloring matter. On the anterior surface of the choroid, just around 
its anterior margin, is a whitish band, one-fortieth of an inch wide, called 
the ciliary ligament, which binds together the cornea and sclerotic and 
the choroid and iris. Extending back, about one-eighth of an inch, on 
the anterior aspect of the choroid, is a gray circular band, called the cili- 
ary muscle. On the posterior aspect of the front of the choroid are, 
about, sixty ridges, diverging from the rim of the choroid, called the 
ciliary processes. 
The Iris. 
The iris is the thin, flat membrane, which continues the choroid in 
front. In its centre is seen the opening, called the pupil. The various 
colors of the iris are due to the difference of color of the pigmentary 
matter found in its cells and to the varying arrangement of the blood 
vessels. The color is darkest usually near the centre. 
Towards the middle of the iris is a circle of little shaggy projections. 
The foundation of the structure of the iris is fibrous tissue, consisting of 
circular and radiating fibres, interposed between which are pigment cells. 
In front and behind this fibrous layer is a layer of pigment cells. In the 
iris are also seen unstriated muscular fibres, circular around the pupil and 
radiating toward the circumference: by the action of these fibres the 
pupil is constantly dilating and contracting. Blood vessels and nerves 
ramify throughout the structure. On the posterior surface the iris con- 
sists of a black layer, called the uvea, which is, in fact, a continuation of 
the membrana pigmenta of the choroid. 
Anterior Chamber—Between the iris and pupil behind, and the cornea 
in front is a small cavity, called the anterior chamber. 
Posterior Chamber—Between the iris and pupil in front, and the lens 
behind is another, smaller cavity, called the posterior chamber. These 
two contain a liquid, called the aqueous humor, and they communicate 
through the pupil, after the sixth month of foetal life, up to which time 
the pupil is closed by a membrane, called the papillary. Both cham- 
bers are lined by a membrane which secretes the aqueous humor. 
The Retina. 
The retina is the innermost of the three coats of the eye, lying The Organ of Vision. 
167 
just within the choroid. It is wanting in front even for a greater dis- 
tance than the two preceding layers, for it ceases, as it reaches the ciliary 
processes, in a rough, ragged margin, called ora serrata, and is continued 
thence to the crystalline lens by a vascular membrane, called the suspen- 
sory ligament of the lens. The outer surface of the ligament is fluted to 
correspond with the ciliary processes, against which it rests. 
The retina is non-resisting and translucent, being partially formed by 
the expansion of the optic nerve, with which it is continuous posteriorly. 
Exactly in the centre, posteriorly, is a round, yellowish spot, called the 
macula lutea, and in the centre of this spot a depression called fovea 
centralis. About one-tenth of an inch to the inner side of this is seen 
the termination of the optic nerve—optic disk, or papilla—showing in its 
centre the arteria centralis retinae, breaking up into branches. From 
this point forward the retina gradually thins to its termination. 
The Vitreous Humor. 
Just within the retina is a bag, called the hyaloid membrane, contain- 
ing a liquid, called vitreous humor. This is similar in composition 
to the aqueous humor, being 98% water. Traversing the centre of this, 
in the fcetus, is a branch of the arteria centralis retinae, making its way to 
the lens, called the capsular artery, it disappears at birth. 
The Crystalline Lens. 
Indenting the front of the hyaloid membrane is found a doubly convex 
transparent body, called the crystalline lens. Its posterior surface is 
much more convex than the anterior, the latter forming the posterior wall 
of the posterior chamber. The lens forms only the bulging portion of 
the wall, the circumference of which is formed by the suspensory ligament 
of the lens, which extends from the ora serrata of the retina to the rim of 
the lens. This ligament is formed of two layers and when it lays hold 
of the lens it leaves a circular canal around it, called the canal of Petit. 
The lens is invested by a transparent homogeneous, elastic membrane, 
the capsule of the lens. In structure the lens consists of a series of con- 
centric layers of parallel fibres, which gradually harden towards the 
centre of the lens. It can also be split into three triangular segments, 
which meet by their apices in the centre of the lens. 
In youth the lens is more convex and much softer than in old age, as 
it gradually becomes, with advancing life, firmer and less convex. Notes on Anatomy. 
THE MUSCULAR SYSTEM, 
When an incission is made in any part of the body, the following 
structures, from without inward, are met with: ist, skin; 2d, superficial 
areolar fascia, whose existence allows the free movement observed in 
almost every part of the integument. It consists of two layers, between 
which is generally found fatty tissue, varying in quantity in different 
parts of the body; 3d, beneath the superficial fascia, in some parts of the 
body, are found the muscles with their proper investing fascia; while in 
others there is interposed between them and the superficial fascia a strong, 
and more or less thick, membrane, called the investing fascia, or deep 
fascia which frequently gives off from its deep face partitions, which sepa- 
rate different groups of muscles. 
The function of muscles is to produce movement, most of them being 
attached to bone, some having no bony attachment, while others are at- 
tached to bone by one extremity the other terminating in some soft tissue. 
When a muscle is attached to bone by both extremities a movable joint 
is almost invariably found between the two extremities, otherwise no 
movement would occur when the muscle attempted to contract, so that, 
as a rule, those muscles, which lay hold of bone at both extremities, are 
attached to different bones at either end. The two attachments of a muscle 
are spoken of, one as the origin, the other as the insertion, the origin 
being usually that attachment susceptible of the least motion, and as a 
rule, especially true of the limbs, the origin is the point nearest the body, 
or the mid-line of the body. The action of a muscle consists in the 
shortening of its length, thus drawing the parts to which it is attached 
nearer, usually by movement of the part into which it is inserted. Some 
movements are too complex to be brought about by one muscle and re- 
sult from the co-ordinated action of several. 
The striated muscles are the red, fleshy portion of the body, though 
generally a muscle consists of two parts: the red fibres, gathered into 
bundles, fasciculi, forming a coarse, or a fine muscle, and a white, tougher, 
stronger portion called its tendon. With few exceptions the tendon is 
found at the extremities of the muscle, and, as it is so much stronger, 
bulk for bulk, the tendon is much the smaller part of the muscle, thus 
economizing space at the attachments. The portion of muscle between 
its tendons of origin and insertion is called the belly of the muscle. In 
a few instances a muscle has two bellies, since it may have a central 
tendon. The Muscular System. 
169 
The names of most muscles are derived from one of the following 
facts: ist, the position which it occupies; 2d, its shape; 3d, the direction 
of its fibres; 4th, its attachments; sth, its action; 6th, the number of its 
origins. 
The Muscles of the Face. 
The muscles of the face are arranged in groups, viz: those connected 
with the orbit, with the nose, the mouth and, a very unimportant, group 
connected with the auricle. 
Orbital Group—Three Muscles. 
Orbicularis Palpebrarum. 
The orbicularis palpebrarum is an elliptical muscle, lying just beneath 
the skin, in front of the orbit, the portion which lies on the lid being 
thinner and paler than the rest. It arises from the tendo oculi and adja- 
cent bone; and the fibres, forming an ellipse around the orbit, return to 
the place from which they started. The tendo oculi is a fibrous cord, 
which is attached by one end to the orbital aspect of the nasal process 
of the superior maxilla, while the other end bifurcates to be attached to 
the inner extremities of the tarsal cartilages. 
Externally the orbicularis palpebrarum is attached to the temporal fascia. 
Action—It closes the eyelids. It is one of the sphincter muscles, but 
in its action differs from most of them in being immovably attached at its 
extremities. When its fibres contract they bring the eyelids together in 
a line corresponding to its points of attachment, whereas most sphincter 
muscles close the aperture which they surround by an approximation of 
all their fibres at the same time, and in the same proportion, towards the 
centre of the aperture, e.g., the orbicularis oris, in the act of whistling, 
since it has no bony attachment. 
Corrugator Supercilii 
The corrugator supercilii is a small muscle, which arises from the inner 
extremity of the superciliary ridge, on each side, passes outward and is 
lost in the deep face of the orbicularis palpebrarum. 
Action—lt throws the skin of the forehead into vertical folds, i. e., cor- 
rugates the brow. 
Tensor Tarsi. 
The tensor tarsi, or Horner’s muscle, is very small. It arises from the 
orbital surface of the lachrymal bone, passes outward and divides into 170 
Notes on Anatomy. 
two portions, which lay hold of the inner extremities of the lids as far 
out as the punctum lachrymale. 
Action—It aids the orbicularis palpebrarum in closing the lids and also 
draws inward the puncta lachrymalia the better to receive the tears. 
The Ocular Group—Seven Muscles. 
The muscles forming this group are found within the orbit. All of 
them, except the levator palpebrae susperioris, are attached to the eye- 
ball, and all, except the two oblique muscles, arise at the apex of the 
orbit and pass forward flat, straight and widening as they advance toward 
their insertion. 
Four of them, from the direction of their fibres, are called recti and 
are concerned in moving the eye-ball. They are distinguished as: ist, 
superior rectus, because it lies above the eye-ball and draws the front of 
the eye upward; 2d, inferior rectus, because it lies below the eye-ball 
and draws its front downward; 3d, external rectus, because it lies exter- 
nal to the eye-ball and draws its front outward; 4th, internal rectus, be- 
cause it lies internal to the eye-ball and draws its front inward. By a 
combined action of these muscles the front of the eye can be moved in 
all directions intermediate between those mentioned. All the recti arise 
from the apex of the orbit, that is the margin of the optic foramen, and 
also receive an origin from the fibrous sheath of the optic nerve. They 
run forward and are inserted into the sclerotic coat about one-fourth of 
an inch behind the circumference of the cornea. Some give as the origin 
of three of these muscles the ligament of Zinn, which is a fibrous band 
attached around the lower portion of the circumference of the optic fora- 
men. This, however, is an unnecessary refinement. These muscles differ 
but slightly in size and length. 
Superior Rectus 
The superior rectus arises from the upper margin of the optic foramen 
and from the fibrous sheath of the optic nerve. It passes forward and is 
inserted in the sclerotic coat one-fourth of an inch behind the cornea. 
It is the thinnest of the recti. 
Inferior Rectus. 
The inferior rectus arises from the lower margin of the optic foramen 
and from the sheath of the optic nerve. It passes forward and is inserted The Muscular System. 
171 
into the under surface of the sclerotic about one-fourth of an inch behind 
the cornea. 
External Rectus. 
The external rectus arises by a forked origin from the outer margin of 
the optic foramen and from the sheath of the optic nerve. It passes for- 
ward and is inserted into the outer surface of the sclerotic coat about 
one-fourth of an inch behind the circumference of the cornea. It is im- 
portant to remember its forked origin, since many nerves pass through 
the interval between its head. 
Internal Rectus 
The internal rectus arises from the inner margin of the optic foramen 
and sheath of the optic nerve. It passes forward and is inserted into the 
inner surface of the sclerotic coat about one-fourth of an inch behind the 
circumference of the cornea. 
Levator Palpebrse Superioris. 
Lying just beneath the orbit, and between it and the superior rectus, is 
a muscle closely resembling the recti, called levator palpebrae superioris 
since its action is to raise the upper lid. It arises from the upper margin 
of the optic foramen and sheath of the optic nerve, passes forward and is 
inserted into the upper edge of the superior tarsal cartilage. 
Inferior Oblique. 
The inferior oblique is a narrow and thin muscle, arising from the or- 
bital surface of the superior maxilla, near the inner side of the orbit. It 
passes out beneath the eye-ball and inferior rectus to be inserted into the 
sclerotic near the entrance of the optic nerve, on the outer under aspect 
of the eye-ball. 
Action—It rotates the eye-ball on its antero-posterior axis. 
Superior Oblique or Trochlearis. 
The superior oblique arises from the inner margin of the optic foramen 
and sheath of the optic nerve. It passes forward along the upper inner 
wall of the orbit to its front, where, becoming tendinous, it plays through 
a cartilaginous ring fixed to the fovea trochlearis : thence its tendon 
passes outward and backward, beneath the superior rectus, to be inserted 172 
Notes on Anatomy. 
into the outer aspect of the sclerotic about half way between the circum- 
ference of the cornea and the entrance of the optic nerve. 
Action—lts action is computed from the pulley at the fovea trochlearis— 
hence it rotates the eye-ball on its antero-posterior axis and draws it for- 
ward. 
Muscles of the Mouth. 
The muscles of the mouth consist of two groups, superior and inferior 
labial groups and one muscle, the orbicularis oris, which belongs to 
both groups. 
Orbicularis Oris. 
The orbicularis oris is the sphincter muscle of the mouth ; as it has 
but slight connection with bone, this attachment may be disregarded. It 
consists of two segments, one in each lip, which meet at the angles of the 
mouth. 
Action It can close the mouth in two ways, either by bringing the 
lips together in a horizontal line or by approximating the angles of the 
mouth at the same time. 
Superior Labial Group—Five Muscles 
Levator Labii Susperioris Alseque Nasi. 
The levator labii susperioris alaeque nasi arises from the nasal process 
of the superior maxilla and descending divides into two slips, one of 
which is inserted into the ala of the nose while the other continues on to 
be inserted in the upper lip. Its name indicates its action. 
Levator Labii Superioris Proprius. 
This muscle arises from the orbital ridge of the superior maxilla and 
descends to be inserted into the upper lip. Its name indicates its action. 
Levator Anguli Oris. 
The levator anguli oris, or canine muscle, arises from the canine fossa 
of the superior maxilla and passes downward and outward to be inserted 
into the angle of the mouth. Its name indicates its action. 
The Zygomatic Muscles—Two. 
The zygomatic are two small muscles which arise from the zygomatic The Muscular System. 
process of the malar bone and pass downward and inward. The zygo- 
maticus major, the lower one, is inserted into the angle of the mouth 
and the zygomaticus minor into the upper lip. 
Action—They carry the angle of the mouth upward and outward. 
Inferior Labial Group—Three Muscles. 
Quadratus Menti. 
The quadratus menti, or depressor labii inferioris, is a square-shaped 
thin muscle which arises from the oblique line on the front of the lower 
jaw near the symphysis and, passing upward, is lost in the lower lip. Its 
synonym indicates its action. 
Triangularis 
The triangularis, or depressor anguli oris, arises by its base just exter- 
nal to the preceding and is inserted by its apex into the angle of the 
mouth. Its synonym indicates its action. 
Levator Labii Inferioris 
The levator labii inferioris lies just beneath the mucous membrane. It 
arises from the incisive fossa of the inferior maxilla and is inserted into 
the integument of the chin. Its action'is indicated by its name. 
Cranial Group—One Muscle. 
Occipito-Frontalis. 
The occipito-frontalis of either side arises from the superior curved 
line of the occipital bone and the mastoid process. It is tendinous at its 
origin but becomes fleshy as it passes forward; and then, as it is mount- 
ing over the vault of the cranium, it forms a broad aponeurosis and de- 
scending on the forehead again becomes fleshy to be lost in the orbicu- 
laris palpebrarum and corrugator supercilii, its innermost fibres forming 
the pyramidalis nasi muscle. 
Action—lt raises the brows and throws the skin of the forehead into 
wrinkles. 
Nasal Group—Three Muscles. 
Pyramidalis Nasi. 
The pyramidalis nasi is formed by the innermost fibres of the occipito- 
frontalis, which descending, are lost on the bridge of the nose. 174 
Notes on Anatomy. 
Action—It draws down the inner extremity of the eyebrow and elevates 
the nose. 
Compressor Naris. 
The compressor naris, triangular in shape, arises from canine fossa in 
the superior maxilla by its apex and, mounting on the side of the nose, 
meets its fellow of the opposite side in a tendinous raphe on the bridge 
of the nose. * 
Action—The two are supposed to expand the nostrils. 
Depressor Alse Nasi. 
The depressor alse nasi is found just beneath the mucous membrane of 
the upper lip. It arises from the incisive fossa of the superior maxilla 
and is inserted into the ala of the nose. Its name indicates its action. 
The muscles of the face are nearly all small and pale and fatty. As a 
rule they arise from bone and are inserted into soft parts. Their action 
produces the varying expression of which the face is capable. 
Muscles of Mastication—Five. 
These muscles produce the various movements of the lower jaw on the 
upper. 
Masseter. 
The masseter arises from the zygoma, from the lower border of the 
malar bone and from the malar process of the superior maxilla. It is 
inserted into the outer surface of the ramus of the lower jaw as far as its 
angle. The muscle is square in shape, its anterior fibres passing down- 
ward and backward, superficial to the posterior fibres which pass down- 
ward and forward. 
Temporal. 
The temporal is a radiated muscle occupying the temporal fossa. It 
arises from the whole of the temporal fossa, from the whole length of the 
temporal ridge and from the temporal fascia which covers it. It passes 
downward, its fibres converging, and is inserted into the apex and inner 
side of the coronoid process of the inferior maxilla. 
Buccinator. 
The buccinator, or trumpeter’s muscle, is the bulkiest element of the 
cheek. It arises from the alveolar process of the superior maxilla, from The Muscular System. 
175 
the external oblique ridge of the lower jaw, as far forward as the second 
bicuspid tooth and from the pterygo maxillary ligament. Its fibres con- 
verge to be inserted into the angle of the mouth. 
The pterygo-maxillary ligament extends from the hamular process of 
the pterygoid plate to the posterior extremity of the molar ridge of the 
lower jaw. In front it gives origin to some of the fibres of the buccinator 
behind to the superior constrictor of the pharynx. 
External Pterygoid 
The external pterygoid muscle arises by a forked origin from the 
pterygoid ridge, the under surface of the outer face of the greater wing 
of the sphenoid, the external pterygoid plate, the tuberosity of the supe- 
rior maxilla and the tuberosity of the palate bone. It passes backward 
and is inserted into the neck of the condyle of the lower jaw and into the 
interarticular fibro-cartilage. 
Internal Pterygoid 
The infernal pterygoid arises from the pterygoid fossa and passing 
downward, backward and outward is inserted into the inner surface of 
the ramus of the lower jaw as far as its angle. 
The Muscles of the Back. 
Those muscles of the back which are here described lie in three super- 
imposed layers. 
First Layer—Two Muscles. 
Trapezius. 
The trapezius arises from the superior curved line of the occipital bone, 
from the posterior occipital protuberance and from the spinous processes 
of all the dorsal and cervical vertebrae. The fibres converge outward, 
some ascending obliquely, some descending obliquely and some running 
horizontally to reach the insertion into the outer third of the clavicle, the 
acromion process and whole length of the spine of the scapula. Its in- 
sertion is the same as the origin of the deltoid. 
Extending from the posterior occipital protuberance to the seventh 
cervical vertebrae, and attached to the intervening spinous processes, is a 
fibrous cord called ligamentum nuchae; and it is in reality from this cord 
that the trapezius arises. 176 
Notes on Anatomy. 
Action—According to the direction of the fibres which act it can draw 
the scapula directly backward, downward and backward or upward and 
backward. 
Latissimus Dorsi. 
The latissimus dorsi arises from the spinous processes of the lower four 
or six dorsal vertebrae, all the lumbar vertebrae and the spinous tubercles 
of the sacrum, from the posterior third of the crest of the ilium and by 
fleshy slips from the three or four lower ribs. The muscle is tendinous 
at its origin except that part arising from the ribs. As it passes upward 
and outward the fibres converge, become thicker and fleshy and passing 
over the lower angle of the scapula, wind around the teres major to be 
inserted along with it into the posterior bicipital ridge of the humerus. 
The tendon of the teres major is wider and extends further down on the 
humerus than that of the latissimus dorsi. 
Action—It carries the humerus downward and backward, rotates it in- 
ward, is an inspiratory agent, and, when the humerus is fixed, as in 
climbing or using crutches, it moves the body forward. 
Second Layer—Two Muscles. 
Levator Anguli Scapulae. 
The levator anguli scapulae arises by tendinous slips from the posterior 
tubercles of the transverse processes of the four upper cervical vertebrae. 
These slips unite to form the belly of the muscle which descends obli- 
quely outward to be inserted into the posterior border of the scapula from 
the angle to the intersection of the spine with that border. Its name 
indicates its action. 
Rhomboideus. 
The rhomboideus arises from the spinous processes of the last cervical 
and four upper dorsal vertebrae, and passing downward and outward is 
inserted into the posterior border of the scapula as far as the inferior 
angle. Some make two muscles of this, calling the portion which arises 
from the cervical vertebra rhomboideus minor and that arising from the 
dorsal vertebrae rhomboideus major. 
Action—It moves the scapula upward and backward 
Third Layer—Three Muscles. 
Serratus Posticus Superior. 
The serratus posticus superior has a tendinous origin from the spinous 
processes of the two lower cervical and two upper dorsal vertebrae. It The Muscular System. 
177 
passes downward and outward and is inserted by fleshy serrations into the 
upper borders of the second, third, fourth and fifth ribs just beyond their 
angles. 
Action—It is an inspiratory agent. 
Serratus Posticus Inferior. 
The serratus posticus inferior has a tendinous origin from the spinous 
processes of the last two dorsal and first two lumbar vertebrae. It passes 
upward and outward and is inserted by fleshy slips into the lower borders 
of the last four ribs. 
Action—It is an expiratory agent. 
Splenius. 
The splenius arises from the spinous processes of the four lower cer- 
vical vertebrae and four or six upper dorsal vertebrae. It ascends and 
divides into two portions, one, known as the splenius capitis, is inserted 
into the occipital bone between its curved lines and into the mastoid por- 
tion and process of the temporal bone; the other, called splenius colli, is 
inserted into the posterior tubercles of the transverse processes of the 
three upper cervical vertebrae. 
Action-—lt bends the head and upper part of the spine back and 
rotates the head toward its side. 
The Muscles of the Thorax 
Triangularis Sterni. 
The triangularis sterni is found on the posterior aspect of the front 
wall of the chest on either side of the sternum. It arises from the edge 
of the sternum and from the costal cartilages from the third to the sixth 
or seventh, and, passing upward and outward, is inserted into the second, 
third, fourth and fifth costal cartilages and corresponding ribs. Its inser- 
tion corresponds to that of its antagonist the serratus posticus superior. 
Action—It is an expiratory agent. 
Intercostal Muscles 
The interval between two ribs is occupied by two layers of muscular 
fibres which extend between the edges of adjacent ribs and are known as 
external and internal intercostal muscles. 178 
Notes on Anatomy. 
The external intercostal muscles, eleven in number, have a direction 
downward and forward, like the external oblique of the abdomen, and 
extend from the tubercle of the ribs to the costal cartilages. 
The internal intercostals, also eleven on each side, have a direction 
downward and backward and extend from the sternum to the angles of 
the ribs, corresponding in the direction of their fibres to the internal ob- 
lique of the abdomen. 
Action—When acting from above they raise the ribs, being inspiratory 
agents. When acting from below they depress the ribs and are expira- 
tory agents. 
Muscles of the Neck. 
Superficial Group—Two Muscles— 
Platysma Myoides. 
When the integument and superficial fascia have been removed from 
the front and side of the neck there is seen a thin pale broad muscle 
called the platysma myoides. It arises from the fascia covering the pec- 
toralis major and deltoid muscles, and passes upward and inward over the 
clavicle to cover the side and front of the neck. Its innermost fibres are 
interlocked with the fibres of the opposite muscle along the upper part 
of the middle line of the neck; the others are inserted into the inferior 
maxilla, some passing over it to be lost on the side of the face and some 
continuing to the angle of the mouth; these last are joined by some 
accessory fibres which take their origin on the side of the face from the 
fascia covering the masseter muscle. These fibres have been considered 
as a separate muscle called risorius Santorini or laughing muscle. 
Action—It is a depressor of the lower jaw. It can draw the angle of 
the mouth downward so as to produce a melancholy expression or carry 
it backward as in laughing. 
Sterno-Cleido-Mastoid. 
The sterno-cleido-mastoid is the second muscle in the superficial 
group and lies beneath the platysma between two layers of the deep cer- 
vical fascia. It is one of the most important muscles in the body and 
derives its name from its origin and part of its insertion. 
It arises by a forked origin. One fork, a more or less rounded tendon, 
springs from the upper front part of the manubrium; the other, musculo- 
tendinous, arises from about the inner one-third or one-half of the clavi- 
cle. This origin is very variable. An interval, filled by fibrous tissue, The Muscular System. 
179 
usually exists between the two heads. The muscle passes obliquely 
upward, backward and a little outward on the side of the neck and is 
inserted into the mastoid portion of the temporal bone and adjacent part 
of the superior curved line of the occipital. Between its two origins 
there is a fissure which extends upward for some distance. 
Action—When both muscles act they bow the head forward; when 
one acts it draws the head to that side, turning the face somewhat to the 
opposite side. 
Depressors of the Hyoid Bone—Four— 
Sterno-Hyoid. 
The sterno-hyoid derives its name from its attachments. It is ribbon- 
like in shape and vertical in direction. It arises from the posterior aspect 
of the manubrium sterni and perhaps from the inner extremity of the 
clavicle or sterno-clavicular ligament, and ascends the neck beside the 
middle line to be inserted into the hyoid bone. 
Sterno-Thyroid. 
Lying behind the sterno-hyoid and slightly broader than it, is another 
ribbon-like muscle called, from its attachments, sterno-thyroid. It arises 
from the posterior surface of the manubrium and possibly from the car- 
tilage of the first rib, and, ascending beside the middle line is inserted 
into the oblique ridge on the ala of the thyroid cartilage. Below it is 
often traversed by a tendinous intersection as is the sterno-hyoid. 
Thyro-Hyoid. 
The thyro-hyoid is a short ribbon-like muscle which continues the 
course of the sterno-thyroid to the hyoid bone, and derives its name from 
its attachments. It arises from the oblique ridge on the ala of the thy- 
roid cartilage and is inserted into the hyoid bone. Frequently some of 
the fibres of the sterno-thyroid are continued directly into this muscle. 
Omo-Hyoid. 
The omo-hyoid derives its name from its attachments. It is a double- 
bellied muscle passing with a curve across the side of the neck. 
It arises from the upper border of the scapula, near the supra-scapular 
notch, and perhaps from the ligament stretched across the notch; and 
Passes forward, inward and slightly upward until, beneath the sterno- 180 
Notes on Anatomy. 
cleido mastoid, it becomes tendinous, its posterior belly ceasing. It then 
again becomes fleshy, forming the anterior belly, and passes nearly up- 
ward but with a slight inclination inward, to its insertion in the hyoid 
bone at the junction of its body and greater cornu. The central tendon 
is held down, so as to give the muscle its curve, by a loop of fascia which 
is said to pass to the cartilage of the first rib. 
Action—The depressors of the hyoid bone, as the name indicates, 
draw the hyoid bone down. The sterno-thyroid draws down the larynx 
and the two omo-hyoids, acting together, draw the hyoid bone down- 
ward and backward. These muscles are sometimes spoken of as the 
infra-hyoid group. 
Elevators of the Hyoid Bone—Five 
Digastric. 
The digastric, as its name indicates, is a double-bellied muscle. It is 
round in shape, curved in direction and found at the upper part of the 
side of the neck. It arises fleshy from the digastric fossa of the temporal 
bone and passing downward and forward, becomes tendinous; the portion 
between its origin and central tendon being called the posterior belly. 
It then again becomes fleshy, forming the anterior belly, and passing for- 
ward and upward is inserted into the digastric fossa of the inferior max- 
illa, The central tendon pierces obliquely the belly of a small muscle 
which lies beside it called the stylo-hyoid, and, after emerging from it, 
plays through a loop of fascia which binds it down to the hyoid-bone. 
Stylo-Hyoid. 
The stylo-hyoid is a small muscle found lying beside the posterior belly 
of the digastric and deriving its name from its attachments. It arises 
from the outer side of the styloid process of the temporal bone, and pass- 
ing downward and forward is inserted into the hyoid bone. Just before 
its insertion it is pierced by the central tendon of the digastric. 
Mylo-Hyoid. 
The mylo-hyoid is a broad, thin, triangular muscle which forms the 
floor of the mouth. It arises from the whole length of the mylo-hyoid 
ridge, and, passing nearly inward, with a slight inclination downward, the 
greater portion of the muscle meets its fellow of the opposite side on the 
middle line, forming a raphe, while some of its posterior fibres are inser- 
ted into the hyoid bone. The Muscular System. 
181 
Genio-Hyoid. 
The genio hyoid is a small muscle which slightly increases in size as it 
descends. It lies beneath the mylo-hyoid just beside the middle line. It 
arises from the inferior spina mentalis and passes backward and slightly 
downward to be inserted into the hyoid bone. 
Genio-Hyo-Glossus 
The genio-hyo-glossus is a thin, radiating, fan shaped muscle. It 
arises by a narrow tendinous origin from the superior spina mentalis and 
immediately radiates, fleshy, to be inserted into the under surface of the 
tongue from its base to near its apex, some of its lower fibres being in- 
serted into the hyoid bone. This muscle lies close to the middle line 
beside its fellow. 
Surgical Triangles of the Neck. 
The side of the neck presents a quadrilateral surface which is bounded 
below by the clavicle, above by the body of the inferior maxilla and an 
imaginary horizontal line passing from its angle to the mastoid process 
of the temporal bone, in front by the middle line and behind by the an- 
terior edge of the trapezius. 
This space is subdivided by the sterno-mastoid into a great anterior 
and a great posterior triangle. The anterior triangle is bounded as fol- 
lows: in front by the middle line, behind by the sterno-cleido-mastoid, 
above by the body of the lower jaw and the imaginary line. The base 
is above, the apex below. The posterior triangle has its base below, 
formed by the clavicle. It is bounded in front by the sterno-cleido-mas- 
toid and behind by the anterior edge of the trapezius. 
Each of these triangles is again subdivided into smaller ones. The 
anterior is divided into three; 
ist. The inferior carotid triangle, or triangle of necessity, is bounded 
m front, by the median line; behind, by the anterior margin of the sterno- 
niastoid; above, by the anterior belly of the omo-hyoid. Its base is in- 
ternal. 
2d. The superior carotid triangle, or triangle of election, is bounded 
behind by the sterno-mastoid; belowr, by the anterior belly of the omo- 
hyoid; above, by the posterior belly of the digastric. Its base is 
external. 182 
Notes on Anatomy. 
3d. The digastric or submaxillary triangle has its base formed by the 
lower jaw and the imaginary line and its sides formed, posteriorly, by the 
posterior belly of the digastric and stylo-hyoid, anteriorly, by the anterior 
belly of the digastric. 
The great posterior triangle is subdivided into two; 
Ist. The suboccipital triangle has its base below. It is bounded in 
front by the sterno-mastoid ; behind, by the anterior edge of the trape- 
zius; below, by the posterior belly of the omo-hyoid. 
2d. The subclavian triangle has its base below. It is bounded above 
by the posterior belly of the omo-hyoid; in front, by the sterno-mastoid; 
below, by the clavicle. It contains the subclavian artery and vein, hence 
its name, and the brachial plexus of nerves. In the posterior triangle the 
subdivisions are made by the posterior belly of the omo-hyoid; in the 
great anterior triangle by the anterior belly of the omo-hyoid, and the two 
bellies of the digastric. 
The Scaleni Muscles. 
The two scaleni muscles form part of a group called praevertebral, the 
rest of the group being unimportant; the only fact connected with them 
worthy of note being that they are interposed between the common caro- 
tid artery and the transverse processes of the cervical vertebrae. 
The two scaleni muscles are distinguished as scalenus anticus and pos- 
ticus. A small portion of the scalenus posticus is sometimes individual- 
ized as the scalenus medius. These muscles are of great importance 
owing to the fact that they occupy a position in the lower part of the 
side of the neck, and come into important relation with the subclavian 
artery and brachial plexus of nerves. 
Scalenus Anticus 
The scalenus anticus, triangular in shape, arises from the anterior tuber- 
cles of the transverse processes of the third, fourth, fifth and sixth cervi- 
cal vertebrae by tendinous slips, which, uniting as they descend, form the 
muscle. It is inserted by a narrow tendon into the upper surface of the 
first rib. 
Scalenus Posticus. 
The scalenus posticus arises from the posterior tubercles of the trans- 
verse process of all the cervical vertebrae except the first. It descends 
and divides into two portions, one of which is inserted into the first rib The Muscular System. 
183 
between its tubercle and angle—and is the part sometimes called scalenus 
medius—while the other goes to the same point on the second rib. 
Action—When acting on the ribs they are inspiratory agents; acting 
on the vertebral column they flex it. 
Muscles of the Larynx. 
The movements on each other of the separate cartilages which consti- 
tute the larynx are mainly effected by five small muscles called the 
intrinsic muscles of the larynx. 
Crico-Thyroid. 
The crico thyroid, a triangular muscle, arises from the front of the 
cricoid cartilage and, passing upward, backward and outward, is inserted 
into the lower border of the thyroid cartilage from the median line in 
Iront to the inferior cornu. 
Action—lt stretches the vocal chords by drawing the thyroid cartilage 
forward and downward on the cricoid. 
Posterior Crico-Arytenoid. 
The posterior crico-arytenoid arises from the depression on the poste- 
rior aspect of the cricoid cartilage and, passing upward, outward and 
forward, is inserted into the outer angle of the base of the arytenoid. 
Action—lt separates the vocal chords by rotating the anterior angle 
of the base of the arytenoid outward, the vocal chord being attached to 
this angle. 
Lateral Crico-Arytenoid. 
The lateral crico-arytenoid arises from the side of the cricoid cartilage, 
and, passing upward, outward and backward, is inserted into the outer 
angle of the base of the arytenoid. 
Action—It is the antagonist of the posterior crico-arytenoid; for, 
rotating the anterior angle of the base of the arytenoid inward, it approxi- 
mates the vocal chords. 
Arytenoid. 
The arytenoid is a single muscle which arises from the concave poste- 
rior face of one arytenoid cartilage and passes transversely across the 
interval between the two to be inserted into the same part of the oppo- 
site cartilage. 184 
Notes on Anatomy. 
Action—By drawing the arytenoid cartilages together it closes the 
glottis. 
Thyro-Arytenoid. 
The thyro-arytenoid arises from the receding angle of the thyroid car- 
tilage just beside and external to the attachment of the vocal chords, and, 
passing backward, parallel with the vocal chord is inserted into the ante- 
rior angle of the base of the arytenoid cartilage. 
Action—By approximating its points of attachment it relaxes the vocal 
chords and is said to throw them into vocalizing position, i. e., the chord 
is thrown with its edge transverse to the length of the air-tube. 
The Abdominal Muscles. 
The anterior abdominal wall is formed chiefly by six flat, thin muscles, 
three on each side of the middle line, called the broad muscles of the 
abdomen. Besides these there are two other pairs, the pyramidales, small 
and insignificant, and the recti which are long and narrow. The abdomi- 
nal wall consists of the following structures from without inward, viz; 
ist, integument; 2d, two layers of superficial fascia with fatty tissue in- 
terposed; 3d, the external oblique muscle; 4th, the internal oblique; sth, 
the transversalis ; 6th, the transversalis fascia; 7th, the parietal layer of 
peritoneum. These muscles all terminate in tendinous fibres as they ap- 
proach the median line; and, since there is no bone for them to seize, 
their fibres interlock, forming a white line extending from the ensiform 
cartilage to the symphysis pubis called the linea alba. The whole line is 
sunken below the surrounding surface and presents about its centre the 
umbilicus or navel. The sunken appearance is caused by the bulging of 
the recti, which lie on either side of it, the width of the linea alba cor- 
responding to the interval between the recti. 
External Oblique. 
The external oblique of the abdomen derives its name from the down- 
ward and inward direction of its fibres and from its position, being external 
to another oblique muscle. It arises by eight fleshy, tooth-like processes 
or digitations from the anterior surface of the eight lower ribs. The upper 
five digitations interlock with similar processes of the serratus magnus, 
the lower three with the latissimus dorsi. From their origin the fibres 
pass downward and inward, the digitations gradually blending to form the 
belly of the muscle which, toward the front of the abdomen, terminates 
in a thin flat tendon, called an aponeurosis, which is inserted into the The Muscular System. 
185 
linea alba from the sternum to the symphysis pubis. The posterior fibres 
pass almost vertically downward and are inserted into about the anterior 
one-half or two-thirds of the outer lip of the crest of the ilium; while 
the intermediate fibres are inserted into the anterior superior spinous pro- 
cess of the ilium and into the spine and pectineal line of the pubes. 
That portion of the aponeurosis which extends from the anterior superior 
spinous process of the ilium to the spine of the pubes is called Poupart’s 
ligament. It is the lower border of the aponeurosis, is free between its 
points of attachment and folded slightly inward on itself. About an inch 
from the spine of the pubes Poupart’s ligament sends downward some 
fibres which are inserted into the pectineal line of the pubis, forming 
Gimbernat’s ligament, which is triangular in shape with its apex with-in 
and its base extending for about an inch outward. 
At the lower, inner part of the aponeurosis is seen an opening, near 
the symphysis pubis, called the external abdominal ring. It is formed by 
a separation of the fibres of the aponeurosis, is triangular in shape and 
oblique in direction, its apex being upward and outward and its base 
downward and inward at the crest of the pubes. The edges of the 
aponeurosis which form the sides of the ring are called its pillars, internal 
and external, the external being inserted into the spine of the pubes and 
the internal interlocking with the internal pillar of the opposite side over 
the front of the pubes. For a short distance the apex of the ring is 
obscured by some curved fibres called intercolumnar fibres. The exter- 
nal abdominal ring transmits in the male the spermatic cord and in the 
female the round ligament. 
SUMMARY. 
Origin—By eight digitations from the external surface of the eight 
inferior ribs. Insertion—Into the whole length of the linea alba, the 
spine and pectineal line of the pubes, the anterior superior spinous 
process of the ilium and the anterior one-half or two-thirds of the crest 
of the ilium. 
Internal Oblique. 
The internal oblique muscle of the abdomen derives its name from the 
upward and inward obliquity of its fibres and from the position it occu- 
pies just beneath the external oblique. It arises by a thin tendinous 
membrane, called the fascia lumborum, from the spinous processes of the 
lumbar vertebrae, the anterior two-thirds of the middle lip of the crest of 
the ilium, and from the outer half of Poupart’s ligament. 
The fascia lumborum terminates in fleshy fibres on the side of the 186 
Notes on Anatomy. 
abdomen, and those fibres springing from the crest of the ilium are also 
fleshy; these radiate somewhat, the general direction, however, being 
upward and inward, and are inserted, posteriorly, into the cartilages of 
the four lower ribs; while on the front of the abdomen the fibres become 
aponeurotic and are inserted into the whole length of the linea alba. 
The fleshy fibres which rise from the outer half of Poupart’s ligament 
are blended with fibres of the transversalis which arise from the same 
part of the ligament. These blended fibres arch downward and inward 
and form, so long as they remain fleshy, the conjoined arch; but as they 
descend they become tendinous, forming the conjoined tendon which is 
inserted into the crest and pectineal line of the pubes. By reason of the 
arched direction of these fibres there is a short space between them above 
and Poupart s ligament below, their conjoined arch without and conjoined 
tendon within, where the wall of the abdomen has but one muscular ele- 
ment, viz: the aponeurosis of the external oblique. If an incision were 
made at this point we would pass through: ist, the integument; 2d, two 
layers superficial fascia; 3d, the aponeurosis of the external oblique; 
4th, transversalis fascia and the parietal layer of the peritoneum. The 
conjoined tendon descends just behind the external abdominal ring, so 
that at this point the wall is wanting in only one muscular element—the 
aponeurosis of the external oblique. 
SUMMARY. 
Origin Outer one-half Pouparts ligament—Anterior two-thirds crest 
of ilium, spinous processes lumbar vertebrae. 
Insertion Lower border four lower costal cartilages, whole length 
linea alba, and, by conjoined tendon, into the crest and pectineal line of 
the pubes. 
Transversalis. 
The transversalis derives its name from the horizontal direction of its 
fibres. It lies just beneath the internal oblique and is the deepest of the 
three broad muscles of the abdomen. It arises by means of an aponeu- 
rosis from the transverse and spinous processes of the lumbar vertebras, 
fleshy from the inner aspect of the cartilages of the six inferior ribs, in- 
terlocking with the diaphragm, fleshy from the anterior two-thirds of the 
inner lip of the crest of the ilium and fleshy from somewhat less than the 
outer half of Poupart’s ligament. The posterior aponeurosis becomes 
fleshy on the side of the abdomen and these fibres, being reinforced by 
those which arise from the costal cartilages and crest of the ilium, pass The Muscular System. 
187 
forward, become aponeurotic and are inserted into the whole length of the 
linea alba. The fibres which rise from Poupart’s ligament blend with 
those of the internal oblique to form the conjoined arch and conjoined 
tendon which is inserted into the crest and pectineal line of the pubes. 
SUMMARY. 
Origin—lnner surface six lower costal cartilages, lumbar vertebrae, 
anterior two-thirds or three-fourths crest of ilium and a little less than 
the outer half of Poupart’s ligament. 
Insertion—Into the whole length of the linea alba and into the crest 
and pectineal line of the pubes. 
Rectus. 
The rectus abdominis derives its name from the straight course of its 
fibres. It lies on the front of the abdomen, beside the linea alba, sur- 
rounded by the aponeuroses of the three broad muscles of the abdomen. 
It is flat and ribbon-like in shape. It arises by a flat tendon from the 
front of the symphysis pubis and crest of the pubes; as it ascends it be- 
comes fleshy and broader and terminates by three digitations which are 
inserted into the fifth, sixth and seventh cartilages just beside the sternum, 
In the upper half of its course the rectus presents three or four tendinous 
intersections which are called line® transversae. Before the aponeurosis 
of the external oblique has been removed, the outer edge of the rectus 
presents a curved ridge called linea semilunaris. The rectus as it as- 
cends is enclosed between the aponeurosis of the three broad muscles, 
and these form what is called its sheath. This sheath is complete in 
front for the whole length of the muscle, but behind is wanting for its 
lower fourth. It is thus formed: for the upper three-fourths of the rec- 
tus, or from a point half way between the umbilicus and the symphysis 
pubis upward to its insertion, the rectus has in front the aponeurosis of 
the external oblique and half the aponeurosis of the internal oblique; 
while for the same distance behind it has the aponeurosis of the transver- 
salis and half of the aponeurosis of the internal oblique, the latter aponeu- 
rosis splitting, when it reaches the outer edge of the rectus, sending one 
layer in front and the other behind that muscle. Of course it also has 
behind it the transversalis fascia and the parietal layer of peritoneum 
separating it from the abdominal cavity. For its lower fourth, that is 
from the point midway between the umbilicus and symphysis pubis, all 
three aponeuroses pass in front of it; and behind it is separated from the 
abdominal cavity only by the parietal layer of the peritoneum and the 188 
Notes on Anatomy. 
transversalis fascia. Where the sheath ends behind it is curved and is 
called the fold of Douglas. 
SUMMARY. 
Origin crest of pubes and front of symphysis pubis. 
Insertion—lnto fifth, sixth and seventh costal cartilages, 
Uppei three-fourths of sheath formed in front by aponeurosis of ex- 
ternal oblique and one-half aponeurosis of internal oblique. 
Upper three-fourths of sheath formed behind by aponeurosis of trans- 
versalis and one-half aponeurosis of internal oblique. 
Lower one-fourth of sheath has in front aponeurosis of the three 
muscles. 
Pyramidalis. 
The pyramidalis abdominis is small and derives its name from its pyra- 
midal shape. It is found in the sheath of the rectus, in front of its lower 
portion, and is frequently absent on one or both sides. It arises from the 
front of the crest of the pubes and passes upward, tapering as it ascends 
to be inserted into the linea alba half way to the umbilicus. 
Action—-The abdominal muscles are agents of expulsion as in voiding 
the urine and faeces and in terminating labor. They are also agents of 
forced expiration, for when they contract they diminish the size of the 
abdominal cavity, forcing the abdominal viscera against the walls of that 
cavity and thus driving the diaphragm upward, while at the same time, 
by drawing down the ribs they in a measure diminish the size of the 
thorax. 
Diaphragm. 
ist. Definition and position—The diaphragm is the arched muscular 
septum between the two cavities of the trunk, presenting its upper con- 
vex surface as the floor of the thorax and its equally concave under sur- 
face as the roof of the abdomen. 
2d. Relations—By its upper surface it supports the pleura on either 
side, containing the lungs, and the pericardium in the centre, containing 
the heart. Below it is covered by peritoneum and is in relation with the 
liver, spleen, stomach, pancreas and kidneys. 
3d. Origin—ln front it arises from the posterior surface of the sternum, 
on each side from the inner surface of the six lower ribs and from a liga- 
mentum arcuatum externum and internum, behind from the front of the 
vertebral column by two crura. The Muscular System. 
189 
4th. Its points of origin studied individually. 
(a) Between that part which arises from the posterior surface of the 
sternum and that part on each side which arises from the adjacent ribs 
there usually exists a fissure for a short distance, the muscular structure 
here being wanting, and the aperture, which would otherwise exist, be- 
tween the thoracic and abdominal cavities being closed by other struc- 
tures. 
(b) The origin from the inner surface of the ribs is by digitation which 
interlock with similar digitations of the transversalis abdominis. 
(c) The ligamentum arcuatum externum arches across the quadratus 
lumborum muscle from the apex of the twelfth rib to the apex of the 
transverse process of the first or second lumbar vertebra, usually the 
second. 
(d) The ligamentum arcuatum internum arches over the psoas magnus 
muscle from the apex of the transverse process of the first or second 
lumbar vertebra to be lost in the crus of the same side. 
(e) The right crus arises tendinous from the front of the bodies of the 
second, third and fourth lumbar vertebrae. 
(/) The left crus arises tendinous from the front of the bodies of the 
second and third lumbar vertebrae. It is smaller as well as shorter than 
the right. 
The muscular fibres of the diaphragm, as they are making for the 
centre, become tendinous. The central portion, therefore, is called the 
tendinous portion and is arranged like a clover leaf, presenting a central, 
a right and a left leaflet, the tendon is therefore called trefoil or central 
tendon. 
sth. The appearances which it presents. 
The diaphragm is pierced by three large apertures which are for the 
transmission of the following structures, viz ; Ist, descending aorta, vena 
azygos major, thoracic duct and sometimes the sympathetic nerve; 2d, 
the ascending vena cava; 3d, oesophagus and pneumogastric nerves. 
The crura, as stated, arise tendinous from the front of the vertebral 
column, but as they ascend they become fleshy and leave a slight inter- 
val between them. Over the front of the twelfth dorsal vertebrae each 
crus gives off from its inner side a bundle of fibres which crosses obliquely 
to join the opposite crus, the one from the right crus being usually in 
front. This interchange of fibres is known as the decussation of the 
crura and it leaves between its commencement and the vertebral column 
an opening which is known as the aortic. This opening is over the front 
of the body of the twelfth dorsal vertebra, usually slightly to the left of 190 
Notes on Anatomy. 
the middle line, but sometimes on it. The opening is behind the dia- 
phragm and not through it. 
The decussating fibres, after passing into the opposite crus, again 
separate from each other leaving an opening around which they again 
unite. This is the oesophageal opening and is situated above and to the 
left of the aortic opening, between it and the middle leaflet, and about 
opposite the tenth dorsal vertebra. 
The opening for the inferior vena cava is to the right of the middle 
line, between the right and middle leaflets of the tendinous centre and 
about opposite the ninth dorsal vertebra. 
6th. Action—The diaphragm is a respiratory muscle and an agent of 
expulsion. When it contracts, as it does eighteen to twenty times a 
minute, it descends, becoming less arched and thus increasing the size of 
the thorax while it decreases the size of the abdomen, though the latter 
is compensated by the bulging of the anterior abdominal walls; but should 
it be necessary to exert a straining effort, as in voiding the urine or faeces 
or in parturition, the muscles of the abdominal wall contract at the same 
time that the diaphragm does, so that the abdominal cavity is diminished 
in size from above downward as well as from before backward, and its 
viscera subjected to compression. When the diaphragm relaxes it again 
ascends, thus lessening the size of the thoracic cavity. 
Quadratus Lumborum. 
The quadratus lumborum is a quadrilateral muscle found in the poste- 
rior abdominal wall, in the lumbar region lying beside the vertebral 
column. 
It arises from the last rib and descends, being attached by its inner 
edge to the transverse processes of the lumbar vertebrae, to be inserted 
into the ilium and the ilio-lumbar ligament. 
Action—It draws the vertebral column to one side, and acts as an 
expiratory agent by drawing down the last rib. 
Muscles of the Upper Extremity. 
Anterior Thoracic Region— 
PECTORALIS MAJOR. PECTORALIS MINOR. SUBCLAVIUS. 
Pectoralis Major. 
The pectoralis major derives its name from its position on the front of 
the chest, and from the fact that there is another muscle smaller than it The Muscular System. 
191 
in the same region. It is coarse in structure, triangular in shape with its 
base within and apex without. It arises fleshy from the sternal two- 
thirds of the clavicle, from the whole length of the front of the sternum 
and from the cartilages of five ribs, i. e. all of true ribs except the first 
and seventh (this origin being by fibres which reinforce the muscle as it 
passes over the ribs) and from the aponeurosis of the external oblique 
muscle of the abdomen. 
The fibres converge as they pass outward. Those from the clavicle 
pass nearly vertically downward, those from the lower part of the ster- 
num and the aponeurosis of the external oblique pass obliquely upward 
and outward and the intermediate fibres pass horizontally outward. They 
all terminate in a folded tendon which is inserted into the anterior bicipi- 
tal ridge of the humerus. As the fibres are approaching their termina- 
tion some fold over the others, those from the lower portion of the origin 
of the muscle passing behind and forming the upper part of the tendon, 
those from the clavicle passing in front and fornfing the lower part of 
the tendon. 
Action—It draws the humerus across the chest. 
SUMMARY. 
Origin—Sternal two-thirds clavicle, whole length front of sternum, 
cartilages of true ribs except first and seventh, aponeurosis of external 
oblique. 
Insertion—By folded tendon into anterior bicipital ridge of the humerus. 
Pectoralis Minor. 
The pectoralis minor derives its name from its position on the front of 
the chest, and from the fact that there is another pectoral muscle of larger 
size. It is found beneath the pectoralis major, is small in size, oblique 
in direction and triangular in shape. It arises from the front of the 
third, fourth and fifth ribs, passes upward and outward, fleshy, narrows 
to a tendon and is inserted into the coracoid process of the scapula. 
Action—Rotates the scapula on the thorax and, when the scapula is 
fixed, aids in expanding the chest. 
Subclavius. 
The subclavius derives its name from its position just beneath the 
clavicle. It is a small round muscle which arises from the cartilage, and 192 
Notes on Anatomy. 
possibly the adjacent osseous portion, of the first rib by a tendon, it 
passes horizontally outward, becomes fleshy, and almost immediately 
after it ceases to rise, begins to be inserted, its belly being extremely 
short, into the whole length of the groove on the under surface of the 
clavicle. This groove occupies about the middle one-third of the clavicle. 
Action—It draws the clavicle downward. 
Thoracic Surgical Triangle. 
Lying just beneath the subclavius, which is sometimes given as its 
upper limit, is a triangular space of surgical importance. It is bounded 
above by the clavicle, below by the upper edge of the pectoralis minor; 
its apex is without and is crossed by the axillary vessels and nerves; its 
base is within and is formed by an imaginary line drawn from the inner 
extremity of the clavicle to the commencement of the origin of the pec- 
toralis minor. 
Lateral Thoracic Region. 
Serratus Magnus. 
The serratus magnus is a large thin muscle found upon the side of the 
chest wall. It derives its name from its extensive origin by means of 
digitations or serrations. 
It arises by nine digitations from the outer surface of the eight upper 
ribs, the lower five interlocking with serrations of the external oblique, 
and two arising from the second rib. Its origin is fleshy, and it continues 
its course, fleshy, outward and backward over the side of the chest, to be 
inserted into the whole length of the anterior edge of the posterior bor- 
der of the scapula. 
Action—It moves the scapula on the thorax and, when the scapula is 
fixed, raises the ribs. 
Acromial Region. 
Deltoid. 
The deltoid is a large, coarse, triangular muscle forming the bulge of 
the shoulder and deriving its name from its resemblance to the Greek letter 
J (delta). It arises from the outer one-third of the clavicle, from the 
acromion process and whole length of the spine of the scapula. Passing 
downward it converges to a short tendon which is inserted into the del- 
toid impression about half way down the outer surface of the shaft of the 
humerus. The Muscular System. 
Action—lt raises the humerus, i. e., abducts it, and by its posterior 
fibres can carry it backward, or by its anterior fibres forward. 
Scapular Group 
SUBSCAPULARIS. 
SUPRA-SPINATUS, 
INFRA SPINATUS. 
TERES MAJOR. 
TERES MINOR. 
Subscapularis. 
The subscapularis is a coarse, flat muscle, which occupies the subscapu- 
lar fossa. It arises from the whole of the fossa with the following excep- 
tions: i. e., a small portion near the superior and inferior angles, a narrow 
strip along the posterior border where the serratus magnus is inserted and 
the outer one-third of the fossa. It also gets some fibres from the fascia 
which invests it, and from the septa sent down by this fascia to seize ridges 
on the venter of the scapula. The muscle passes upward and outward 
toward the neck of the scapula, narrows to a tendon as it approaches the 
humerus, and is inserted into the lesser tuberosity of the humerus and 
into the bone for an inch below. 
Action—It is an inward rotator of the humerus. 
Supra-Spinatus. 
The supra-spinatus lies in the supra-spinous fossa on the dorsum of 
the scapula. It arises from the whole of the fossa, except its outer third, 
and form the investing fascia of the muscle and, passing forward beneath 
the acromion process, narrows to a tendon which is inserted into the 
highest of the three muscular impressions on the great tuberosity of the 
humerus. As the spine forms a part of this and the infra-spinous fossae 
it is unnecessary to mention it separately in describing the origin of the 
two muscles. 
Action—lt aids the deltoid in raising or abducting the humerus and is 
an outward rotator. 
Infra-Spinatus 
The infra-spinatus arises from the whole of the infra-spinous fossa, 
except its outer third, and from the investing fascia covering the muscle. 
Passing upward and outward it is inserted into the middle of the three 
muscular impressions on the great tuberosity of the humerus. 
Action—lt is an outward rotator of the humerus. 194 
Notes on Anatomy. 
Teres Minor. 
The teres minor lies along the lower edge of the infra-spinatus, from 
which it is separated by a septum of fascia. It arises from the upper 
two-thirds of the axillary border of the scapula and ascends to terminate 
in a tendon which is inserted into the lowest of the three muscular im- 
pressions on the great tuberosity of the humerus. 
Action—lt is an outward rotator of the humerus. 
Teres Major. 
The teres major lies just below the teres minor from which, after its 
origin, it is separated by a widening interval. It arises from the lower 
one-third of the axillary border of the scapula and from a small portion 
of the dorsum of the scapula near its inferior angle and, passing upward 
and outward, is inserted by a flat tendon into the posterior bicipital ridge 
of the humerus. 
Action—lt draws the humerus downward and backward. 
Surgical Triangle. 
Between the two teres muscles there is a triangular space whose base 
is the humerus and whose sides are formed as follows: above, by the lower 
border of the teres minor; below, by the upper border of the teres 
major. This space is subdivided by the long head of the triceps, into a 
quadrilateral and triangular space. The boundaries of the quadrilateral 
space are as follows: posteriorly the long head of the triceps; anteriorly 
the humerus; inferiorly the teres major; superiorly the teres minor. The 
small triangular space is bounded in front by the long head of the triceps, 
which forms its base: above by the teres minor; below by the teres 
major. 
Muscles of the Humerus or Arm. 
BICEPS FLEXOR. 
BRACHIALIS ANTICUS. 
TRICEPS. 
CORACO BRACHIALIS. 
When the skin and two layers of superficial fascia have been removed 
from the arm (that part of the upper extremity which extends between 
the shoulder and the elbow) there is exposed a strong, fibrous membrane, 
called the deep fascia, which forms a complete investment for the limb, 
binding down the muscles and sending a septum from its inner surface to The Muscular System. 
195 
the internal and external condyloid ridges, to separate the muscles on the 
front from that on the back of the humerus. They are known respect- 
ively as internal and external intermuscular septa. 
The muscles of the arm are divided into two groups, anterior and pos- 
terior. 
Anterior Humeral Group. 
Biceps Flexor. 
The biceps, as its name indicates, has a forked origin arising by two 
tendons, one, its short head, from the coracoid process of the scapula in 
common with the coraco-brachialis; the other, the long head, from the 
upper margin of the glenoid cavity of the scapula, where it blends with 
the glenoid ligament. The belly of the muscle, formed from these two 
origins, descends on the front of the arm to the elbow where it terminates 
in a tendon which, after giving off a slip from its inner side to the deep 
fascia of the forearm, is inserted into the posterior part of the bicipital 
tuberosity of the radius. 
Action—It flexes the forearm, i. e., draws it forward and upward on 
the arm, and is also a supinator of the forearm. 
Coraco-Brachialis. 
The coraco-brachialis is a short muscle which rises in common with 
the short head of the biceps from the coracoid process of the scapula, 
descends on the inner side of the biceps, to which it is adherent for a 
short distance, and is inserted into a vertical ridge about the middle of 
the inner surface of the shaft of the humerus. 
Action—lt is a flexor of the arm and can also carry the arm inward 
across the chest. 
Brachialis Anticus. 
The brachialis anticus is the fleshy mass which lies beneath the biceps 
on the lower part of the front of the arm. It arises by two digitations 
which embrace the deltoid “V” and from the front of the shaft of the 
humerus from that point to within an inch of the elbow, from the whole 
of the internal intermuscular septum and from the external intermuscular 
septum for a few inches. It passes over the elbow and is inserted into 
the front of the coronoid process of the ulna. The muscle is cut off 
from part of the external intermuscular septum by the origin of the 
supinator longus and the extensor carpi radialis longior. 
Action—lt is a flexor ot the forearm. 196 
Notes on Anatomy. 
Posterior Humeral Group. 
Triceps Extensor. 
The triceps is the large fleshy mass which covers nearly the whole of 
the posterior aspect of the humerus, and is the only muscle found there. 
It arises by three heads, known as long (or middle), short (or internal) 
and external, which is intermediate in length. The long head arises 
from the upper inch of the axillary border of the scapula, while the other 
two arise from the whole of the posterior aspect of the shaft of the hume- 
rus, from the insertion of the teres major internally and the teres minor 
externally, downward to the condyles, and from the external and internal 
intermuscular septa. It is inserted into the depressed surface on the ole- 
cranon process of the ulna. The origin may be stated by starting at the 
insertion and tracing the muscle upward, when the internal head will be 
seen to arise from the inner half of the posterior aspect of the humerus 
and the internal intermuscular septum, the outer head from the outer 
half of the posterior aspect of the humerus and external intermuscular 
septum and the long head from the upper inch of the axillary border of 
the scapula, the three uniting about the middle of the arm to form the 
belly of the muscle. 
Action—It extends the forearm on the arm. 
Muscles of the Forearm. 
The muscles of the forearm are divided into those on the front and 
those on the back of the forearm. The deep fascia of the arm is con- 
tinued over the elbow and invests the forearm, giving off from its inner 
surface septa, known as intermuscular or dividing septa, which separate 
the muscles from each other. 
Muscles on the Front of the Forearm. 
PRONATOR RADII TERES. 
FLEXOR CARPI RADIALIS. 
First Layer. 
Second Layer. 
FLEXOR LONGUS POLLICIS 
FLEXOR PROFUNDUS DIGITORUM. 
FLEXOR CARPI ULNARIS. 
PALMARIS LONGUS. 
PRONATOR QUADRATUS. 
FLEXOR SUBLIMIS DIGITORUM. 
The muscles on the front of the forearm have for their action the pro- 
duction of the following movements: The Muscular System. 
197 
ist. Pronation, or revolution of the radius around the ulna, thus turn- 
ing the palm of the hand downward or rather backward—for the anatomi- 
cal position exists, when the palm of the hand looks forward. 
2d. Flexion of the hand at the wrist, i. e., bringing the hand forward 
on the forearm. 
3d. Flexion of the fingers on the hand or at the inter-phalangeal 
joints. 
4th, Flexion of the thumb on the hand. 
To produce pronation there are two muscles, the round pronator 
(pronator radii teres) and the square (pronator quaratus). To produce 
flexion at the wrist joint there are three muscles, two known as flexors 
of the carpus while the third has the unfortunate name of palmaris 
longus. The two flexors are distinguished as radial and ulnar from 
the bones near which they lie instead of being named internal and ex- 
ternal as they should be. To produce flexion of the fingers there are 
two muscles called superficial and deep since the one lies on the other. 
Each muscle sends a tendon to each of the four fingers. To produce 
flexion of the thumb there is one muscle of the forearm, called the long 
flexor of the thumb to distinguish it from the short flexor which is found 
in the hand. 
The muscles on the front of the forearm seem to have a preference, as 
a bony origin, for the internal condyle of the humerus; many also take 
origin from the deep fascia, which adheres to them closely for about three 
inches below the elbow. No muscle, of course, can arise from this fascia 
which is not superficial in the upper part of the forearm. Another point 
of origin for some of them is the intermuscular or dividing septa. As 
so many muscles spring from these sources, we speak of them as having 
a common origin which, for muscles on the front of the forearm, is thus 
stated, viz: internal condyle, intermuscular septa and deep fascia. 
The muscles of the forearm are divided into two layers. 
First, or Superficial Layer. 
Pronator Radii Teres. 
The pronator radii teres has a double origin, from the common origin 
and from the coronoid process of the ulna. It is inserted into the middle 
third of the oblique line of the radius. 198 
Notes on Anatomy. 
Flexor Carpi Radialis. 
The flexor carpi radialis arises from the common origin and is inserted 
into the base of the metacarpal bone of the index finger. Its tendon 
grooves the trapezium. 
Palmaris Longus 
The palmaris longus arises from the common origin, and is inserted 
into the palmar fascia, and anterior annular ligament. 
Flexor Carpi Ulnaris. 
_ exor carpi ulnaris arises from the common origin, from the inner 
side of the olecranon and by a strong aponeurosis from the upper two- 
thirds of the posterior border of the ulna. It is inserted into the base of 
the metacarpal bone of the little finger, enclosing the pisiform as a sesa- 
moid bone. 
Flexor Sublimis Digitorum, 
The flexor sublimis digitorum has five points of origin—ist, internal 
lateral ligament of the elbow; 2d, coronoid process of the ulna; 3d, the 
oblique line of the radius for several inches, and from the common origin. 
This really makes six points, but the first is common to all the foregoing 
muscles. It descends beneath the superficial layer of muscles, and 
divides into four tendons at the lower part of the forearm, which enter 
the hand and proceed, one to each finger, to be inserted into the side of 
the shaft of the second phalanx. At the base of the fingers it splits to 
allow the passage of the tendon of the deep flexor, unites and then again 
splits to be inserted into the side of the second phalanx. 
Second Layer. 
Flexor Profundus Digitorum. 
The flexor profundus digitorum lies just beneath the sublimis and to 
the ulnar side of the next muscle. It arises from the upper two-thirds of 
the ulna and from the ulnar part of the interosseeus membrane, divides 
into four tendons, which enter the palm of the hand and, separating, run 
one to each of the fingers, pierce the tendon of the superficial flexor at 
the base of the fingers, and are inserted into the base of the last phalanx. The Muscular System. 
199 
Flexor Longus Pollicis. 
The flexor longus pollicis lies to the outer side of the preceding mus- 
cle. It arises from about the middle two-fourths of the front of the 
radius and from the radial part of the interosseous membrane, and is in- 
serted into the base of the last phalanx of the thumb. 
Pronator Quadratus 
The pronator quadratus, as its name imports, is quadrilateral. Occu- 
pying the lower fourth of the forearm, it prevents the origin of the two 
preceding muscles for that distance. It arises from the inner side of the 
ulna, receiving a few fibres from its front as it passes over it, and is 
inserted into the front of the radius as far as its outer side. 
Interosseous Membrane. 
The interosseous membrane, mentioned above, is a strong fibrous 
membrane stretched between the two bones. It economizes weight, 
while it furnishes as stable an origin for muscles as does bone. 
Posterior Region. 
The muscles upon the back of the forearm also have a common origin, 
viz; external condyle of humerus, investing fascia and intermuscular 
septa. 
They are divided into three groups, each containing four muscles, 
called radial, superficial and deep groups. These muscles, are either ex- 
tensors or supinators, acting in opposition to those on the front of the 
forearm. 
Radial Group. 
SUPINATOR LONGUS. EXTENSOR CARPI RADIALIS LONGIOR. 
EXTENSOR CARPI RADIALIS BREVIOR. SUPINATOR BREVIS. 
Supinator Longus. 
The supinator longus derives its name from the facts that it is a supi- 
nator of the arm and that there is another supinator called brevis. 
It arises from the upper two-thirds of the external condyloid ridge and 
from the external intermuscular septum, and, after descending about two- 200 
Notes on Anatomy. 
thirds of its course, terminates in a tendon which is inserted into the base 
of the styloid process of the radius. 
Extensor Carpi Radialis Longior. 
The extensor carpi radialis longior derives its name from the action of 
the muscle and from the fact that there is another radial extensor which 
is shorter. It arises from the lower one third of external condyloid ridge 
and from the external intermuscular septum, and descends to be inserted 
by its tendon into the base of the metacarpal bone of the index finger. 
Extensor Carpi Radialis Brevior. 
The extensor carpi radialis brevior, deriving its name from the facts 
slated with the preceding muscle, arises from the common origin and is 
inserted into the base of the metacarpal bone of the middle finger. 
Supinator Brevis. 
The supinator brevis arises from the external condyle of the humerus, 
the external lateral and orbicular ligaments and from the triangular de- 
pressed surface beneath the lesser sigmoid cavity of the ulna. It winds 
around the radius and is inserted into the upper third of its oblique ridge. 
Back of Forearm—Superficial Group. 
EXTENSOR COMMUNIS DIGITORUM. 
EXTENSOR MINIMI DIGITI. 
EXTENSOR CARPI ULNARIS. 
ANCONEUS. 
Extensor Communis Digitorum 
The extensor communis digitorum derives its name from its action as 
the extensor common to the four fingers. It arises from the common 
origin and, descending, divides into four tendons, which are each inserted 
into the four lesser fingers along the whole length of the back of each. 
Extensor Minimi Digiti. 
The extensor minimi digiti is an offshoot of the common extensor and, 
as its name indicates, has for its function the extension of the little finger. 
It arises from the common origin and is inserted into the whole length 
of the back of the little fingers along with the slip furnished that finger 
by the common extensor. The Muscular System. 
201 
Extensor Carpi Ulnaris. 
The extensor carpi ulnaris derives its name from its action as an exten- 
sor of the hand and from its situation on the ulnar side of the forearm. 
It arises from the common origin and from the middle third of the poste- 
rior border of the ulna, and is inserted into the base of the metacarpal 
bone of the little finger. 
Anconeus. 
The anconeus is a small triangular muscle which arises by its apex 
from the external condyle of the humerus, and is inserted by its base into 
the olecranon process and triangular surface at the upper extremity of 
the ulna. It is really an offshoot of the triceps extensor, and its action is 
to aid that muscle in extending the forearm on the arm. 
Deep Group. 
The four muscles of this group lie beneath those of the superficial 
group, and all arise from the interosseous membrane as one attachment. 
As indicated by their names, they are all extensors, three being appro- 
priated by the thumb and one by the index finger. 
Extensor Ossis Metacarpi Pollicis. 
The extensor ossis metacarpi pollicis arises from the the radius, ulna 
and interosseous membrane and is inserted into the base of the metacar- 
pal bone of the thumb. 
Extensor Primi Internodii Pollicis. 
The extensor primi internodii pollicis arises from the radius and inter- 
osseous membrane and is inserted into the base of the first phalanx of the 
thumb. 
Extensor Secundi Internodii Pollicis. 
The extensor secundi internodii pollicis arises from the ulna and inter- 
osseous membrane and is inserted into the base of the first phalanx of the 
thumb. 
Extensor Indicis. 
The extensor indicis arises from the ulna and interosseous membrane 
and is inserted into the whole length of the back of the index finger, 
blending with the tendon furnished that finger by the common extensor. Notes on Anatomy. 
Action—All of these muscles are extensors, their names indicating the 
bone on which they act. 
Posterior Annular Ligament. 
This is an oblique fibrous band passing downward and inward across 
the back of the wrist from the lower extremity and styloid process of the 
radius to the cuneiform and pisiform bones. It holds the extensor ten- 
dons down on the bones and gives off from its deep face septa which, 
being attached to bone, form six compartments, through which the ten- 
dons thus separated play. 
The Muscles of the Hand, 
The central portion of the palm of the hand is depressed below the 
level of a prominence on either side, one, extending from the base of the 
little finger toward the wrist, called the hypothenar eminence, and the 
other, considerably more prominent, extending upward from the base of 
the first phalanx of the thumb toward the wrist, called the thenar emi- 
nence. 
When the skin has been removed a thick layer of fatty tissue is ex- 
posed, which serves as a protection for the vessels and nerves in grasping 
with the hand; and beneath this is a strong fascia called the palmar fascia. 
It has a thick central portion and two thinner lateral portions which cover 
the muscles forming the thenar and hypothenar eminences. Tracing this 
fascia to the wrist, it is found to be continuous with a strong fibrous band 
which extends across the wrist from one side to the other, binding down 
the tendons which pass beneath it, known as the anterior annular liga- 
ment. 
The muscles of the hand consist of two groups, the thenar and hypo- 
thenar groups, and four small muscles found in the depressed portion of 
the hand, called lumbricales. 
Thenar Group—Four Muscles. 
The muscles of the thenar group are appropriated to the thumb, the 
movements of which are as follows: (a) Abduction, or movement of the 
thumb outward from the index finger, (b) Adduction, a movement in 
the opposite direction, {d) Flexion, in which the thumb is put in con- 
tact with the palp of any of the fingers. This is effected by putting in 
motion the metacarpal bone of the thumb by a muscle called opponens. The Muscular System, 
203 
(c) Extension, movement in the opposite direction effected by muscles 
on the back of the forearm, which have been described. 
Abductor Pollicis. 
The abductor pollicis arises from the trapezium bone and anterior an- 
nular ligament, and is inserted into the outer side of the base of the first 
phalanx of the thumb. 
Flexor Ossis Metacarpi Pollicis. 
The flexor of the metacarpal bone of the thumb, or the opponens pol- 
licis, arises from the trapezeium bone and anterior annular ligament, and 
is inserted into the whole length of the radial border of the metacarpal 
bone of the thumb. 
Flexor Brevis Pollicis. 
The flexor brevis pollicis consists of two parts, one of which, the super- 
ficial portion, arises from the trapezium bone and annular ligament, and 
the other, or deep portion, from the trapezoid, os magnum and base of 
the metacarpal bone of the middle finger. It is inserted into both sides 
of the base of the first phalanx of the thumb, its tendons of insertion 
having sesamoid bones in them. 
Adductor Pollicis. 
The adductor pollicis is a flat triangular muscle which arises by its 
base from the whole length of the front of the metacarpal bone of the 
middle finger. It is inserted into the inner side of the base of the first 
phalanx of the thumb. 
Hypothenar Group. 
Palmaris Brevis. 
The palmaris brevis is a small pale muscle lying just beneath the skin 
of the palm. It arises from the palmar fascia and the anterior annular 
ligament, and passing inward, about an inch wide, is inserted into the 
skin on the inner border of the hand. 
Abductor Minimi Digiti. 
The abductor minimi digiti arises from the pisiform bone and is inserted 
into the inner side of the base of the first phalanx of the little finger. 204 
Notes on Anatomy. 
Action—It is an abductor of the little finger, i. e., draws the little finger 
inward away from the ring finger. 
Flexor Brevis Minimi Digiti 
The flexor brevis minimi digiti arises from the unciform process of the 
unciform bone and the anterior annular ligament, and is inserted into the 
base of the first phalanx of the little finger. 
Action—It is a flexor of the little finger. 
Adductor Ossis Metacarpi Minimi Digiti. 
The adductor ossis metacarpi minimi digiti arises from the unciform 
process of the unciform bone and the anterior annular ligament, and is 
inserted into the whole length of the metacarpal bone of the little finger. 
Action—It draws the metacarpal bone of the little finger outward and 
forward, carrying the little finger towards the thumb. 
Flexor Tendons of the Fingers. 
It has been seen that the tendons of the flexor sublimis digitorum split 
at the base of the fingers to allow the passage of the tendons of the flexor 
profundus, unite and again split to be inserted into the sides of the shaft 
of the second phalanx of each finger. Before its insertion each tendon 
gives off thread-like prolongations, called vincula accessoria, which are 
inserted into the sides of the bones; and both tendons are bound down 
to the bones by transverse bands of ligamentous fibres called the thecse. 
Muscles of the Lower Extremity. 
The muscles of the lower extremity are divided into those of the hip, 
thigh, leg and foot. The hip is called the gluteal region. 
Gluteal Region. 
As in the upper extremity, the muscles are here covered by an invest- 
ing fascia, which is much thicker and stronger than in the former situa- 
tion, known in the thigh as the fascia lata or vagina femoris. 
The muscles of the gluteal region, nine in number, are arranged in 
three layers, each of which has a muscle called gluteus. The Muscular System. 
205 
First Layer 
Gluteus Maximus 
The gluteus maximus is a quadrilateral muscle, the largest and coarsest 
in the body, and forms the bulge of the buttock. It arises from the pos- 
terior fifth of the crest of the ilium, from the dorsum ilii between the 
superior curved line and the crest, from the posterior surface of the sac- 
rum and cocyx and from the greater sacro-sciatic ligament. It passes 
obliquely downward and outward to be inserted into the line leading from 
the trochanter major to the linea aspera and into the fascia lata. 
Action—It is an abductor and outward rotator of the thigh, a tensor of 
the fascia lata and steadies the pelvis on the femur. 
Second Layer. 
GLUTEUS MEDIUS. 
PYRIFORMIS. 
GEMELLUS SUPERIOR. 
GEMELLUS INFERIOR. 
OBTURATOR INTERNUS. 
QUADRATES FEMORIS. 
Gluteus Medius. 
The gluteus medius is partially covered by the gluteus maximus. It 
arises from the anterior four-fifths of the crest of the ilium, from the dor- 
sum ilii between the middle curved line and the crest and from the investing 
fascia, which covers its outer front part. It is inserted into the outer part 
of the trochanter major. On its outer edge the muscle is continuous 
with the gluteus maximus. 
Action—lt is an abductor and outward rotator of the thigh, steadies 
the pelvis on the femur and aids in carrying the lower extremity forward 
in progression. 
Pyriformis 
The pyriformis is a pear-shaped muscle. It arises within the pelvis by 
three fleshy slips interposed between the anterior sacral foramina from 
the first to the fourth and from the adjoining part of the ilium. It escapes 
from the pelvis through the greater sacro-sciatic foramen, passes down- 
ward and outward, and is inserted into the posterior border of the upper 
extremity of the trochanter major, or into the digital pit. 
Action—It is an external rotator of the thigh. 206 
Notes on Anatomy. 
The Gemelli. 
The gemelli are a pair of small muscles lying one above and the other 
below the tendon of the obturator internus. 
The gemullus superior arises from the spine of the ischium, runs 
horizontally outward and is inserted into the digital pit of the trochanter 
major. 
The gemellus inferior arises from the tuberosity of the ischium, passes 
horizontally outward and is inserted into the digital fossa. 
Action—Both are outward rotators of the thigh. 
Obturator Internus. 
The obturator internus arises within the pelvis from the inner surface 
of the obturator membrane, from the margin of the obturator foramen 
and from the inclined plane of the ischium. Its course is downward and 
slightly backward until, becoming tendinous, it escapes from the pelvis 
through the lesser sacro-sciatic foramen, and passing horizontally out- 
ward, its tendon winding around the posterior border of the ischium just 
below the spine, it is inserted into the digital fossa of the trochanter 
major. 
Action—It is an outward rotator of the thigh. 
Quadratus Femoris, 
The quadratus femoris, as its name indicates, is a square muscle which 
lies below the tendon of the obturator internus. It arises from the tuber- 
osity of the ischium, and is inserted into the posterior intertrochanteric 
line. 
Action—It is an outward rotator of the thigh. 
Third Layer. 
GLUTEUS MINIMUS. OBTURATOR EXTERNUS. 
Gluteus Minimus. 
The gluteus minimus lies beneath the gluteus medius and maximus. 
It is a triangular radiated muscle which arises from the dorsum ilii be- 
tween the middle and inferior curved lines. It passes down, narrowing The Muscular System. 
207 
as it descends, and is inserted into the anterior border of the trochanter 
major. In front it is continuous with the gluteus medius. 
Action—lt is an abductor and inward rotator of the thigh. Acting 
from below it steadies the pelvis on the femur. 
Obturator Externus 
The obturator externus arises from the inner two-thirds of the outer 
surface of the obturator foramen. It narrows to a tendon, which, pass- 
ing outward behind the neck of the femur, is inserted into the digital pit 
of the trochanter major. It lies on the capsular ligament of the hip- 
joint. 
Action—It is an external rotator of the thigh. 
Femoral Region. 
The muscles of the thigh are arranged in four groups, viz; posterior, 
superficial, anterior and internal femoral groups. Investing the thigh, 
just beneath the skin and superficial fascia, is a strong, thick, fibrous 
membrane descending to the knee it invests the joint and passes on to 
become the investing fascia of the leg. From the hip to the knee it is 
known by three names, investing fascia of the thigh, vagina femoris, or, 
generally, fascia lata. It not only forms a firm resisting covering for the 
muscles, but sends in septa between the groups. Two of these septa 
attached to the lips of the linea aspera, are known respectively as the 
external and internal intermuscular septa. The fascia lata consists of 
layers between which are found three muscles of the thigh forming the 
superficial femoral group. 
The posterior femoral muscles have a common origin from the tuber 
ischii and are all three flexors of the leg, i. e., they raise the leg back- 
ward on the thigh. 
Posterior Femoral Region. 
BICEPS FLEXOR CRURIS. SEMITENDINOSUS. 
SEMIMEMBRANOSUS. 
Biceps Flexor Cruris. 
The biceps, as its name imports, arises by two heads. The long head 
springs in common with the semitendinosus from the tuberosity of the 208 
Notes on Anatomy. 
ischium and descends adherent to the semitendinosus for several inches. 
It then accompanies the semitendinosus, but no longer adherent to it, to 
the lower third of the thigh; is joined by the short head which arises 
from the whole length of the outer lip of the body of the linea aspera 
and from the external intermuscular septum. The muscle thus formed 
after descending to the lower third of the femur in contact with the semi- 
tendinosus, leaves that muscle and makes for the outer side of the knee 
joint, where it is inserted chiefly into the head of the fibula, but sends 
some fibres to the outer tuberosity of the tibia and to the fascia of the 
leg. 
Semitendinosus. 
The semitendinosus arises in common with the long head of the biceps, 
adheres to it for several inches and then descends in contact with it to the 
lower third of the thigh where it leaves the biceps and passes to the 
inner aspect of the knee-joint where it is inserted into the inner surface 
of the shaft of the tibia, below the inner tuberosity sending a slip to the 
fascia of the leg. This is known as the “goose foot” insertion. It is 
made up of three muscles, viz: semitendinous, sortorius and gracilis. 
Semimembranosus. 
The semimembranosus arises from the tuberosity of the ischium just 
in front of the preceding muscles and descends in company with them to 
the lower third of the femur whence it accompanies the semitendinous to 
the inner side of the knee-joint and receives a three-fold insertion, viz: 
into the horizontal groove on the inner tuberosity of the tibia, into the 
popliteal fascia and into the posterior ligament of the knee-joint. 
These three muscles are spoken of as the hamstring muscles, the 
biceps being the outer, the semimembranous and semitendinosus being 
the inner. 
Popliteal Space. 
On the posterior aspect of the knee-joint there is a surgical space 
known as the popliteal. It is diamond-shaped and has four angles. It 
is formed, superiorly by the divergence of the hamstring muscles and 
inferiorly by the covergence of the two heads of the gastrocnemius and 
its boundaries are as follows: its outer sides are formed above by the 
biceps, below by the outer head of the gastrocnemius; its inner, above 
by the internal hamstring muscles, below by the inner head of the gas- 
trocnemius. Its superior angle is formed by the divergence of the pos- The Muscular System. 
209 
terior femoral muscles; the inferior by the convergence of the heads of 
the gastrocnemius; the internal lateral by the intersection of the semi- 
tendinous and semimembranous and the inner head of the gastrocnemius; 
the external lateral by the intersection of the biceps and external head of 
the gastrocnemius. 
The floor of the space is formed by three parts. The upper part is 
the posterior aspect of the lower third of the femur;,the middle portion 
is the posterior ligament of the knee-joint; the lower part is the popliteal 
fascia covering the popliteus muscle and corresponds to the upper fifth of 
the tibia. 
The space is important from the fact that passing through it from above 
downward are (a) a large artery, {d) a little more superficial a large vein 
and (c) most superficial of all, a large nerve, all called popliteal. 
Superficial Femoral Group, 
TENSOR VAGINAE FEMORIS. 
GRACILIS. 
SARTORIUS. 
Tensor Vaginae Femoris. 
The tensor vaginae femoris is a short flat muscle found lying on the 
outer aspect of the thigh between the two layers of the fascia lata. It 
arises from the outer lip of the crest of the ilium near the anterior supe- 
rior spinous process, descends with an inclination backward and is inser- 
ted into the fascia lata about one-fourth down the thigh. 
Action—lt is a tensor of the fascia lata and aids in rotating the limb 
inward. 
Sartorius 
The sartorius is the longest muscle in the body. It arises from the 
anterior superior spinous process of the ilium and half the notch below, 
passes obliquely downward and inward across the upper third of the 
thigh, descends vertically behind the internal condyle of the femur and 
then turns obliquely forward to be inserted into the upper inner face of 
the tibia below the internal tuberosity, sending a slip to the fascia of the 
leg. It forms one of the elements of the “goose foot” insertion, the 
other two being the semitendinous and gracilis. The sartorius is the 
most superficial at the insertion, then the gracilis and the semitendinosus 
is the deepest. 
Action—lt flexes the thigh on the pelvis, the leg on the thigh and car- 
ries it inward across its fellow. 210 
Notes on Anatomy. 
Gracilis. 
The gracilis arises by a thin broad aponeurosis from the edge of the 
symphysis pubis and from the margin of the ischio-pubic-ramus. It 
soon becomes fleshy and passes down the inner aspect of the thigh to be 
inserted into the upper inner part of the tibia, below the inner tuberosity, 
sending a slip to the fascia of the leg, i. <?., it is an element of the “goose 
foot” insertion. 
Action—lt flexes the leg on the thigh and aids in adducting the thigh. 
Anterior Femoral Region. 
PSOAS MAGNUS. 
ILIACUS INTERNUS. 
VASTUS EXTERNUS. 
VASTUS INTERNUS. 
Rectus Femoris 
The muscles in this region are usually described as five but can very 
readily be considered as two, viz : Biceps flexor femoris, consisting of 
psoas magnus and iliacus internus and the triceps extensor cruris consis- 
ting of rectus femoris, vastus internus and vastus externus. The last three 
are inserted by a common tendon, called the ligamentum patellae, into the 
anterior tubercle of the tibia, their action being transmitted through the 
patella to which they are attached. 
As might be inferred from their action they all arise from some point 
perpendicular to their insertion. 
Psoas Magnus. 
The psoas magnus is a long spindle shaped muscle lying beside the 
vertebral column and descending into the thigh. It arises from the 
bodies and bases of the transverse processes of the last dorsal, and all 
the lumbar vertebrae; from the intervertebral disks between them and 
from tendinous arches attached to the bodies of the vertebrae, extending 
from the upper lipped edge to the similar lower edge of each vertebra, 
thus leaving between it and the central constricted portion of the vertebra 
an interval through which vessels and nerves pass. The muscle descends 
beside the vertebral column to the pelvis and, as it pass beneath Pou- 
part’s ligament, is joined by the iliacus internus and their blended tendon 
is inserted into the trochanter minor of the femur and the bone for an 
inch below. 
Action—lt is a flexor of the thigh on the pelvis. The Muscular System. 
211 
Iliacus Interims. 
The iliacus internus arises from the iliac fossa, from the internal lip of 
the crest of the ilium and by a few fibres from the capsular ligament of 
the hip-joint. It blends with the psoas magnus and is inserted with it 
into the trochanter minor of the femur and the bone for an inch below. 
Rectus Femoris. 
The rectus femoris derives its name from the straightness of its course. 
It arises by a forked tendon, one fork springing from the anterior inferior 
spinous process of the ilium, the other from the upper margin of the 
acetabulum. The two soon unite, and the tendon thus formed after a 
short course terminates in the belly of the muscle; and that in turn ter- 
minates at the lower part of the thigh in a strong tendon, which is 
inserted into the upper end of the patella. The fibres of this muscle 
have a bipenniform arrangement. 
Vastus Externus. 
The vastus externus arises from the base of the trochanter major, from 
the line leading from the trochanter major to the linea aspera, from the 
upper half or third of the outer lip of the linea aspera, and from the ex- 
ternal intermuscular septum. It is inserted into the outer edge of the 
tendon of the rectus femoris and outer edge of the patella. 
Vastus Internus. 
The vastus internus arises from the whole of the shaft of the femur 
from the anterior intertrochanteric line downward, from the inner lip of 
the linea aspera, and from the internal intermuscular septum. It is in- 
serted into the inner edge of the tendon of the rectus femoris and inner 
edge of the patella. 
The origin of the muscle is also thus stated; from the inner surface of 
the shaft of the femur, from the anterior trochanteric line downward, 
from the front and outer faces, from the internal lip of the linea aspera 
and the internal intermuscular septum. 
The insertion of the three muscles should be thus stated: They com- 
bine to form a common tendon, the tendon of the triceps extensor cruris, 
which encloses the patella as a sesamoid bone and is inserted, as the liga- 
nientum patellae, into the lower part of the anterior tubercle of the tibia. 212 
Notes on Anatomy. 
The vasti muscles envelop the entire femur except the middle lip of the 
linea aspera and the two extremities of the bone. That portion of the 
vastus internus which arises from the front of the femur is sometimes 
described as a separate muscle under the name of the crureus. 
Internal Femoral Region. 
PECTINEUS. 
ADDUCTOR LONGUS. 
ADDUCTOR BREVIS. 
ADDUCTOR MAGNUS. 
The muscles of this region are adductors of the thigh, that is, they 
carry the thigh towards or across its fellow, and consequently they must 
all arise near the middle line of the body. 
Pectineus. 
The pectineus arises from the pectineal line and triangle of the pubes 
and the outer face of Gimbernat’s ligament. It passes downward and 
is inserted into the upper part of the line leading from the trochanter 
minor to the linea aspera. 
Adductor Longus 
The adductor longus arises from the front of the pubes just below the 
angle and close to the symphysis. It passes downward and outward and 
is inserted into the middle third of the linea aspera. This muscle and 
the pectineus form a layer, behind which is found the adductor brevis. 
Adductor Brevis. 
The adductor brevis arises from the body and ramus of the pubes. It 
passes downward and outward and is inserted into the whole length of 
the line leading from the trochanter minor to the linea aspera, its inser- 
tion extending further down than that of the pectineus. 
Adductor Magnus. 
The adductor magnus arises from the side of the tuber ischii and from 
the ischio-pubic ramus. It passes downward and outward in large dis- 
tinct bundles of fibres and is inserted into the whole length of the linea 
aspera and by a rounded tendon into the internal condyle of the femur. 
This muscle is pierced by five apertures, one above the other, which 
transmit branches of the femoral artery. The lowest is much the largest The Muscular System. 
213 
and transmits the termination of the femoral artery itself, over which the 
adductor longus and magnus throw a tendinous arch to the vastus inter- 
ims, forming what is called Hunter’s canal. 
Scarpa’s Triangle. 
On the upper front part of the thigh there is an important triangle, 
known as Scarpa’s. Its outer boundary is the sartorius, its inner the ad- 
ductor longus, its base is Poupart’s ligament, its apex the intersection of 
the sartorious and the adductor longus. Entering this triangle at the 
middle of its base and passing through it to disapper at its apex are the 
femoral artery and femoral vein. 
Muscles of the Leg. 
The muscles of the leg are divided into three regions, viz; ist, anterior 
tibial; 2d, posterior libial; 3d, external or fibular. 
Posterior Tibial Region 
Superficial Layer, 
GASTROCNEMIUS 
PLANTARIS. 
SOLEUS. 
The muscles in the posterior region are placed in two layers, super- 
ficial and deep. 
Gastrocnemius. 
The gastrocnemius is the large muscle which gives shape to the calf 
of the leg. It arises by two heads from the upper back part of the con- 
dyles of the femur and from the ridges which connect the condyles with 
the linea aspera. The two heads, as they descend, converge to form the 
lower lateral boundaries of the popliteal space, and unite to form the belly 
of the muscle along which a groove is continued for some distance. The 
belly terminates just below the centre of the leg in a large tendon called 
the tendo Achilles, which is inserted into the lower back part of the pos- 
terior tuberosity of the os calcis. It is the largest tendon in the body. 
Action—lt raises the heel, and continuing to act, raises the foot. 
Soleus. 
The soleus is a large fleshy muscle lying beneath the gastrocnemius. 
It has five points of origin, viz: the head and upper half of the posterior 214 
Notes on Anatomy. 
aspect of the fibula, the popliteal line and middle third of the internal 
border of th*e tibia and from a tendinous arch stretched between its bony 
origins. The muscle descends to terminate about the middle of the leg 
in the tendo Achilles. 
Action—Same as the gastrocnemius. 
Plantaris. 
The plantaris is an insignificant muscle lying between the gastrocne- 
mius and soleus. It arises from the back part of the external condyle of 
the femur in common with the external head of the gastrocnemius, the 
belly of the muscle passing downward and inward between the gastrocne- 
mius and soleus to terminate in a tendon which, escaping to the inner 
side of the two muscles, passes down either to be inserted into the pos- 
terior tuberosity of the os calcis or to be lost in the side of the tendo 
Achilles. 
Action—Same as gastrocnemius. 
The three muscles just described form the triceps surse. 
Deep Layer 
POPLITEUS. 
TIBIALIS POSTICUS. 
FLEXOR LONGUS DIGITORUM. 
FLEXOR LONGUS POLLICIS. 
Popliteus. 
The popliteus is a small triangular muscle resembling the anconeus in 
the upper extremity. It arises by its tendinous apex from a groove on 
the external condyle of the femur and passes downward and inward, ad- 
hering to the head of the fibula, the posterior ligament of the knee-joint 
and the under surface of the fascia which covers it is inserted into the 
tibia above and as low down as the oblique or popliteal line on its poste- 
rior face. 
Action—It flexes and inverts the leg. 
Flexor Longus Pollicis. 
The flexor longus pollicis arises from the lower two-thirds of the fibula, 
except the last, inch, and from the intermuscular septum. It descends 
behind the internal malleolus into the sole of the foot, crosses the tendon 
of the flexor longus digitorum and is inserted into the base of the last 
phalanx of the great toe. 
Action—It flexes the last phalanx of the great toe. The Muscular System. 
215 
Flexor Longus Digitorum. 
The flexor longus digitorum arises from the lower two-thirds of the 
tibia, except the last two or three inches, and from the intermuscular 
septum. It passes downward behind the internal malleolus, divides into 
four tendons, which are crossed by the flexor longus pollicis, and are 
inserted into the last phalanges of the four outer toes. Its action is indi- 
cated by its name. 
Tibialis Posticus. 
The tibialis posticus arises from the whole length of the posterior sur- 
face of the interosseous membrane, from the adjacent edges of the tibia 
and fibula and from the intermuscular septum. It descends behind the 
internal malleolus and is inserted into the tuberosity of the scaphoid bone 
and into the internal cuneiform bone. 
Action—It is an extensor and adductor of the foot. 
The three last muscles all arise from the interosseous membrane; and 
as the flexor longus pollicis arises from the outer bone of the leg and is 
inserted into the inner toe, it must cross the flexor longus digitorum. 
This crossing takes place in the sole of the foot and is known as the de- 
cussation of the tendons, which are connected at this point by a small 
slip. 
The interosseous membrane is a strong ligamentous membrane which 
passes from tibia to fibula and is attached to thfeir adjacent edges, after 
the manner of the interosseous membrane of the forearm. On its poste- 
rior aspect it is entirely appropriated by the tibial muscles. The muscles 
in the deep layer are separated from those in the superficial layer by a 
strong thick fascia. 
Anterior Region of the Leg. 
TIBIALIS ANTICUS. EXTENSOR LONGUS DIGITORUM. 
EXTENSOR PROPRIUS POLLICIS. 
Of the three muscles in this group two have four points of origin in 
common. These four points are as follows: ist, outer tuberosity of the 
tibia; 2d, investing fascia of the leg; 3d,' intermuscular septum; 4th, inter- 
osseous membrane. 
Tibialis Anticus 
The tibialis anticus arises from the common origin and from the upper 
two-thirds of the outer face of the tibia. It passes downward to termi- 216 
Notes on Anatomy. 
nate in a tendon which runs beneath the anterior annular ligament and is 
inserted into the inner and under surface of the internal cuneiform bone 
and into the base of the metatarsal bone of the great toe. 
Action It flexes the foot; and, according as it acts with the tibialis 
posticus or the peronei, it inverts or everts the foot. 
Extensor Longus Digitorum. 
The extensor longus digitorum arises from the common origin and 
from the head and whole length of the shaft of the fibula. It descends 
and divides into five tendons, which pass beneath the anterior annular 
ligament and are inserted as follows: one into the base of the metatarsal 
bone of the little toe, the other four into the backs of the four lesser toes 
after the manner of extensor tendons. That part of the muscle inserted 
into the base of the metatarsal bone of the little toe, and arising from the 
lower tourth of the fibula, is sometimes called the peroneus tertius. 
Action—It extends the toes; and, by its insertion into the metatarsal 
bone of the little toe, flexes the foot. 
Extensor Proprius Pollicis. 
The extensor proprius pollicis is shorter than the two preceding mus- 
cles and lies between and is overlapped by them. It arises from the mid- 
dle two-fourths of the shaft of the fibula and from the interosseous mem- 
brane, and terminates in a tendon which passes beneath the anterior 
annular ligament and is inserted into the base of the last phalanx of the 
great toe. Its action is indicated by its name. 
The anterior annular ligament is a strong oblique ligamentous band 
which binds the tendons of the three preceding muscles down on the 
front of the ankle. 
External Region of the Leg. 
PERONEUS LONGUS 
PERONEUS BREVIS. 
Peroneus Longus. 
The peroneus, or fibularis, longus arises from the head and upper two- 
thirds of the outer aspect of the shaft of the fibula, from the investing 
fascia and the intermuscular septum. It descends to terminate in a ten- 
don which passes behind the external malleolus, through the lower groove 
on the outer surface of the os calcis, reaches the sole of the foot and is The Muscular System. 
217 
directed across it obliquely forward and inward, through a groove in the 
cuboid bone, to be inserted into the base of the metatarsal bone of the 
great toe. 
Action—It is an extensor of the foot. 
Peroneus Brevis. 
The peroneus, or fibularis, brevis derives its name from its position and 
because its origin and insertion are both short of the preceding muscle, 
beneath which it lies. It arises from the lower two-thirds of the outer 
aspect of the shaft of the fibula and from the intermuscular septum, de- 
scends behind the external malleolus, through the upper groove on the 
outer surface of the os calcis, and is inserted into the base of the meta- 
tarsal bone of the little toe. 
Action—lt extends the foot. 
The two peronei muscles, as they are passing the outer malleolus, are 
held down by the external annular ligament. 
Muscles of the Foot 
The foot is divided into two regions, dorsal and plantar, 
Dorsum of the Foot. 
Extensor Brevis Digitorum. 
The extensor brevis digitorum arises from the upper and outer aspect 
of the os calcis and passing forward and inward divides into four tendons 
the innermost of which is inserted into the base of the first phalanx of 
the great toe, the other three into the backs of the next three toes in 
common with the long extensor tendons. 
Its name indicates its action. 
The Sole of the Foot. 
When the thick skin on the sole of the foot has been removed, there is 
brought into view a thick mass of fatty tissue and beneath this a strong 
fascia called the plantar fascia. It consists of a strong, thick central por- 
tion and, on either side, continuous with this, a thinner lateral portion. 
The central portion begins behind at the under surface of the os calcis, 
runs forward and just beyond the middle of the sole divides into five 
branches each of which passes forward to the base of a corresponding 218 
Notes on Anatomy. 
toe. The muscles of the sole all lie beneath (or, in the erect position, 
above) this fascia and are divided into groups in accordance with the 
subdivisions of the plantar fascia, viz: a central and two lateral groups. 
The propriety of this division is shown by the fact that the plantar fascia 
sends up to the bone intermuscular or dividing septa from the line of 
union of the central and two lateral portions. 
In describing these muscles, however, they are taken in layers, of which 
there are three. When the plantar fascia, the dissection of which is the 
first step, has been removed, the first layer, consisting of one muscle in 
each group, is exposed. This constitutes the second view in the dissec- 
tion of the sole. 
First Layer. 
ABDUCTOR POLLICIS. ABDUCTOR MINIMI DIGITI. 
FLEXOR BREVIS DIGITORUM. 
The three muscles forming the first layer have a common origin, viz: 
ist, the under surface of the os calcis; 2d, the plantar fascia which covers 
them; 3d, the intermuscular septa which separate them. Some of the 
plantar fascia should be left on the muscles in dissecting them, since it is 
a part of their origin. 
Abductor Pollicis. 
The abductor pollicis is the innermost of the three muscles of the first 
layer. It arises from the common origin and is inserted into the inner 
side of the base of the first phalanx of the great toe. 
Its name indicates its action. 
Abductor Minimi Digiti. 
The abductor minimi digiti is the outer of the three muscles in the 
first layer. It arises from the common origin and is inserted into the 
outer side of the base of the first phalanx of the little toe. 
Its name indicates its action. 
Flexor Brevis Digitorum. 
The flexor brevis digitorum lies in the centre of the first layer. It 
arises from the common origin, passes forward and divides into four 
tendons for the four lesser toes. Each tendon splits to allow the passage 
of the tendon of the long flexor and is inserted into the sides of the shaft 
of the second phalanx. 
Its name indicates its action. The Muscular System. 
219 
Second Layer 
MUSCULUS ACCESSORIUS. 
LUMBRICALES. 
The second layer, exposed by removing the first, is the third view in 
the dissection of the sole. It consists of the musculus accessorius, the 
lumbricales and the tendons of the flexor longus pollicis and flexor longus 
digitorum. These two tendons, soon after entering the sole from behind 
the internal malleolus, cross each other [forming their decussation and 
are also connected by slips so that one muscle cannot act independently 
of the other, but throws the part to which it is attached into slight motion. 
Musculus Accessorius. 
The musculus accessorius arises tendinous and fleshy from the under 
surface of the os calcis and passing forward is inserted into the outer 
side and upper surface of the tendon of the flexor longus digitorum just 
as it splits into its four branches. 
Action—lt corrects the obliquity which would otherwise be imparted 
to the four lesser toes by the action of the long flexor. 
Lumbricales. 
The lumbricales are four little worm-like muscles, three of which arise 
from the bifurcation of the tendon of the flexor longus digitorum, while 
the fourth springs from the inner side of the inner tendon of that muscle. 
They pass between the toes and are inserted into the tibial side of the 
extensor tendons of the four lesser toes. 
Action—They aid the flexor longus digitorum. 
Third Layer 
FLEXOR BREVIS POLLICIS. 
ADDUCTOR POLLICIS. 
FLEXOR BREVIS MINIMI DIGIT! 
TRANVERSUS PEDIS. 
This layer, constituting the fourth layer in the dissection of the sole of 
the foot, is exposed by removing the second layer. 
Flexor Brevis Pollicis. 
The flexor brevis pollicis arises from the cuboid bone, the external 
cuneiform bone and the expanded tendon of the tibialis posticus. It is 220 
Notes on Anatomy. 
inserted into both sides of the base of the first phalanx of the great toe, 
each tendon having a sesamoid bone in it. 
Adductor Pollicis 
The adductor pollicis arises from the cuboid bone, from the sheath of 
the tendon of the peroneus longus and from the bases of the adjoining 
metatarsal bones (second, third and fourth). It is inserted into the outer 
side of the base of the first phalanx of the great toe. 
Flexor Brevis Minimi Digiti. 
The flexor brevis minimi digiti arises from the base of the fifth meta- 
tarsal bone and is inserted into the outer side of the base of the first 
phalanx of the little toe. 
Transversus Pedis 
The transversus pedis arises by slips from the heads of the four outer 
metatarsal bones, and passing inward is inserted into the outer side of the 
base of the first phalanx of the great toe. 
Action—lt is an adductor of the great toe. 
Interosseous Muscles. 
Lying between the metacarpal bones of the hand and the metatarsal 
bones of the foot are certain small muscles called from their position 
interosseous. In each member there are seven of these muscles, four 
dorsal and three plantar. They are bipenniform muscles, arising from 
the metacarpal or metatarsal bone and inserted into the first phalanx. 
The first dorsal interosseous of the hand is much larger than the others 
and is called the abductor indicis. 
The Vascular System 
The vascular system comprises three sets of vessels—ist, capillaries, 
minute vessels, ramifying in all parts of the body; 2d, veins, the channels 
for transmission of the deoxygenated blood back to the centre of circu- 
lation; 3d, arteries, the vessels which carry the blood from the heart to 
the capillaries. The Arteries. 
221 
THE ARTERIES. 
The arterial system consists of two parts, the pulmonary and the sys- 
temic. The pulmonary is formed by the pulmonary artery, and its 
branches convey venous blood from the right ventricle to the lungs. 
The systemic consists of the aorta and its branches, which convey arterial 
blood to all parts of the body. 
The branches of the aorta, in the aggregate, greatly exceed the size of 
the aorta from which they are all remotely derived; and the capillaries, 
in the aggregate, are indefinitely larger than the arteries themselves. 
The progress of the blood is, therefore, much slower as the size of the 
channel increases in proportion to its remoteness from the centre of cir- 
culation; and the course of the blood is still more retarded by the tortu- 
ousness of some of the arteries, thus protecting their delicate coats. 
As a rule arteries seek the most sheltered route they can obtain, 
avoiding the surface and lying near bone when practicable. When pass- 
ing through muscular parts they seek the interstices between muscles; 
and when forced to perforate a muscle the aperture is always surrounded 
by a tendinous arch to avoid the compression of the artery, which would 
otherwise result, when the muscle contracted. Another provision for 
their safety is the fibrous sheath which isolates the arteries from the 
structures through which they pass, and protects them from inflammation 
or other disease which may affect the part. 
The names of arteries are, as a rule, derived from the parts which they 
occupy or which they are Intended to supply. As a rule the name of an 
artery remains unchanged, irrespective of the number or size of the 
branches it gives off, until it divides into two or more terminal branches. 
The two exceptions to this rule are found in the arteries of the upper and 
lower extremities, which are known under different names in different 
parts before they divide. 
Another noteworthy point is that arteries usually supply the parts 
through which they course, so that they are constantly diminishing in 
size. The walls of the arteries do not absorb the blood they transmit, 
but are nourished by vessels of their own called vasa vasorum. 
The arteries are usually accompanied by the veins which return the 
blood from the parts which the arteries supply. The veins may be sin- 
gle, when they bear the name of the artery they accompany, or double. 222 
Notes on Anatomy. 
when they lie one on either side of the artery, and are known as satellite 
veins or venae comites. The venous channel from a part is generally 
about twice the size of the arterial to it, and consequently the venous cur- 
lent is much slower than the arterial; it increases in speed, however, as it 
approaches the heart, owing to the diminishing size of the channel. 
Pulmonary Artery. 
The pulmonary artery begins at the base of the venous ventricle of the 
heart, the infundibulum, or conus arteriosus of that cavity leading up to 
it. Its origin is opposite the upper border of the third costal cartilage of 
the left side, close to the edge of the sternum, in front of and slightly 
above and to the right of the origin of the aorta. It is about two inches 
m length, its direction being upward, backward and very slightly to the 
left. It lies in the fibrous pericardium, which it pierces and immediately 
divides into the right and left pulmonary arteries. It and the ascending 
part of the arch of the aorta are contained in the same fold of serous 
pericardium. 
It first lies on the front of the ascending part of the arch of the aorta 
but soon gets to the left of that vessel, more on account of the obliquity 
of the aorta than its own inclination to the left. 
On each side of its origin is an appendix of a corresponding auricle 
and a coronary artery. Its bifurcation is immediately below the trans- 
verse part of the arch of the aorta; from the left branch of the pulmo- 
nary artery, near its bifurcation, there springs a fibrous cord about half an 
inch long, the remains of the ductus arteriosus which connects it with 
the arch of the aorta. 
The two terminal branches, the right and left pulmonary arteries, pass 
almost horizontally outward for about two inches each to the inner face 
of the corresponding lung, where it bifurcates for distribution to the lung. 
The right is slightly larger than the left and somewhat longer. It passes 
behind the ascending part of the arch of the aorta and the superior vena 
cava. The left passes in front of the descending part of the arch. Each 
forms an element in the root of the lung, lying between the bronchus be- 
hind and the two pulmonary veins in front. The right is on a lower, the 
left on a higher level than the corresponding bronchus. 
The Aorta. 
The aorta begins at the base of the arterial ventricle and terminates by 
dividing into the common or primitive iliac arteries on the front of the The Arteries. 
223 
body of the fourth lumbar vertebra, usually a little to the left of the 
middle line. It lies first in the thoracic cavity and then in the abdominal. 
It first passes upward, forward and to the right in the fibrous pericar- 
dium, pierces the pericardium and arches backward and to the left, with 
its convexity upward, and strikes the thoracic portion of the vertebral 
column at the left side and lower border of the body of the fourth dorsal 
vertebra, and then descends beside the body of the fifth dorsal vertebra 
with a slight inclination to the right. From the left side of the lower 
border of the fifth dorsal vertebra it descends, steadily inclining to the 
right, to a point opposite the twelfth dorsal vertebra usually a little to the 
left of the middle line, where it passes from the thorax into the abdomen 
through the aortic opening in the diaphragm. From this point its course 
is down the front of the lumbar vertebrae, generally inclining to the left, 
to its termination. 
For convenience of description it is divided into the arch of the aorta 
and the descending aorta. The arch of the aorta begins at the base of 
the left ventricle and extends to the left side and lower border of the fifth 
dorsal vertebra. It is subdivided into the ascending, transverse and de- 
scending parts of the arch. The descending aorta begins where the arch 
terminates at the lower border and left side of the body of the fifth dor- 
sal vertebra, and includes the remainder of the artery. It is divided into 
the thoracic aorta, and the abdominal aorta in accordance with the cavity 
in which it lies. 
The Arch of the Aorta 
Ascending Part. 
The ascending part of the arch of the aorta, or as it is frequently 
called, the ascending aorta, begins at the base of the arterial ventricle of the 
heart, at a point behind the left edge of the sternum, at the third inter- 
costal space, on a plane posterior to the origin of the pulmonary artery 
and anterior to the left auriculo-ventricular opening. It is about two 
inches in length. It is directed upward, to the right and slightly forward, 
presenting a slight curve in its course with its convexity to the right: it 
terminates in the transverse part of the arch where it pierces the pericar- 
dium, opposite the right edge of the sternum, behind the upper border 
of the second costal cartilage of the right side. Just above its origin it 
presents, when distended, three bulging prominences which correspond 
to the sinuses of Valsalva. It lies in the fibrous pericardium, about one- 
fourth of an inch behind the sternum, and is contained in the same fold 
of serous pericardium as the pulmonary artery. 224 
Notes on Anatomy. 
It first lies behind the pulmonary artery, but quickly gets to the right 
of that vessel, owing mostly to its own inclination to the right. Above 
the point where the pulmonary artery leaves its front it is separated from 
the sternum by the pericardium, some loose connective tissue and per- 
haps the remains of the thymus gland. It is overlapped in front, at its 
origin, by the right auricular appendix. Behind it is the root of the 
right lung. To the right is first the right auricle and then the superior 
vena cava. To the left is the pulmonary artery. 
Transverse Part 
The transverse part of the arch of the aorta begins where the ascend- 
ing part pierces the pericardium behind the right edge of the sternum, 
on a level with the upper border of the second costal cartilage of the right 
side. Its course is curved with its convexity upward, its direction being 
to the left and backward. It strikes the left side and lower border of the 
body of the fourth dorsal vertebra and terminates there by becoming the 
descending part of the arch of the aorta. 
The top of the arch is about an inch below the top of the sternum, 
and from this aspect arise three large branches, the arteria innominata, 
left common carotid and left subclavian. Resting on the arch, in front 
of the origin of these branches, is the left vena innominata or great 
transverse vein of the neck. 
Below it is the bifurcation of the pulmonary artery to which it is con- 
nected by the remains of the ductus arteriosus. Below it also is the left 
bronchus and the left recurrent or inferior laryngeal nerve. This nerve 
springs from the pneumogastric as it is lying on the front of the artery, 
passes below' it and finally winds up behind it, bearing thus a three-fold 
relation to the artery. 
This portion of the arch is separated from the sternum by the left 
pleura, the anterior border of the left lung and the remains of the thymus 
gland. It is crossed from above downward, on its front aspect, by two 
great nerves, the left pneumogastric and the left phrenic, the phrenic 
being directly in front of the pneumogastric and both lying to the left of 
the middle line. 
Behind the transverse part of the arch, on the middle line, we have 
first the trachea and behind that the oesophagus, and to the left of these 
the thoracic duct and left recurrent laryngeal nerve. The Arteries. 
225 
Descending Part of the Arch. 
The descending part of the arch of the aorta begins where the trans- 
verse part terminates, at the left side and lower border of the body of the 
fourth dorsal vertebra. It runs downward, with a slight inclination to the 
right, to terminate by becoming the thoracic portion of the descending 
aorta at the left side and lower border of the body of the fifth dorsal 
vertebra. 
In front is the root of the left lung, behind, the body of the fifth dorsal 
vertebra; to the left, the left pleura and lung; to the right, the oesopha- 
gus and thoracic duct. 
The Thoracic Aorta. 
The thoracic portion of the descending aorta begins by being a con- 
tinuation of the descending part of the arch of the aorta at the left side 
and lower border of the body of the fifth dorsal vertebra and terminates 
by becoming the abdominal portion of the descending aorta at the aortic 
opening in the diaphragm opposite the front of the body of the twelfth 
dorsal vertebra generally slightly to the left of the middle line. Its di- 
rection is downward and steadily but slightly to the right, and presents 
a curve with a slight concavity in front to correspond with the dorsal 
portion of the vertebral column on which it rests. 
It lies in the posterior mediastinum, behind the pericardium, covered 
in front and to the left by the left pleura and lung. Its most important 
relations are the thoracic duct and the oesophagus. The thoracic duct is 
continuously behind and slightly to the right. The oesophagus, on which 
are the two pneumogastric nerves, lies at first to the right but as it de- 
scends gets gradually in front of the aorta and terminates by piercing the 
diaphragm opposite the tenth dorsal vertebra not only in front but to the 
left. To the right is the right or great azygos vein, opening into which, 
about the sixth dorsal vertebra, is the left azygos vein which crosses be- 
hind the aorta. • 
The Abdominal Aorta. 
The abdominal portion of the descending aorta begins by being a 
continuation of the thoracic portion at the aortic opening in the dia- 
phragm (behind the diaphragm really) opposite the twelfth dorsal vertebra 
and slightly to the left of the middle line, and terminates by dividing into 
the common or primitive iliacs on the front of the body of the fourth 226 
Notes on Anatomy. 
lumbar vertebra, usually slightly to the left of the middle line but fre- 
quently on it. Its direction is downward and generally slightly to the 
left, presenting a slight curve with its convexity forward in conformity 
with the lumbar portion of the spine upon which it rests. It is markedly 
smaller at its termination, owing to the size and member of the branches 
which it gives off. 
In front it has the stomach, upon either side the two semilunar ganglia 
of the sympathetic system, forming, by their branches, the solar plexus 
of nerves on the front of the aorta; next comes the head of the pancreas, 
and immediately below this the left renal vein, the transverse portion of 
the duodenum and the mesentery. Below this it is covered in front and 
at the sides by the peritoneum and the aortic plexus of sympathetic 
nerves. 
Behind its upper part, opposite the second lumbar vertebra, is the com- 
mencement of the thoracic duct, the receptaculum chyli, and it is separa- 
ted from the lumbar vertebrae by the left lumbar veins. To the left are 
the left crus of the diaphragm and part of the sympathetic nerves. To 
the right are the right crus of the diaphragm, the inferior vena cava and, 
at its upper part, the right vena azygos and thoracic duct. 
The termination of the abdominal aorta corresponds to a point on the 
anterior abdominal wall half an inch below and to the left of the umbili- 
cus, about on a level with a line drawn between the highest parts of the 
crests of the ilia. 
Branch of the Ascending Aorta. 
The branches of the ascending aorta are two small arteries called coro- 
nary, left or anterior and right or posterior, which are distributed to the 
heart. These arise close to the origin of the aorta and run in the ante- 
rior and posterior interventricular furrows, meeting at the apex of the 
heart and in the auriculo-ventricular grooves, thus forming around the 
heart two vascular zones, one vertical and one horizontal. 
Branches of the Arch of the Aorta. 
The branches of the arch of the aorta are three. The one to the right 
is the arteria innominata, destined to supply the right side of the head 
and neck and right upper extremity; the middle branch is the left com- 
mon carotid, supplying the left side of the head and neck; the left branch 
is the left subclavian, whose field of distribution is the left upper ex- 
tremity, The arteria innominata supplies parts corresponding to those The Arteries, 
227 
supplied by both the left common carotid and left subclavian, and is, in 
fact, the fused right common carotid and subclavian. 
Arteria Innominata. 
The arteria innominata is the first and doubly the largest branch of the 
arch of the aorta. It arises at the commencement of the transverse 
part of the arch of the aorta and passes upward and to the right for a 
little less than two inches to terminate behind the upper border of the 
right sterno-clavicular articulation by dividing into the right common 
carotid and right subclavian arteries. 
Relations—In front of it is the sternum, some loose connective tissue, 
and, near its origin, the left vena innominata. Behind, at its commence- 
ment, is the trachea; but, owing to the obliquity of the artery, it soon 
gets to the right of the trachea, which then lies on the left side of the 
arteria innominata. On the right is the right vena innominata and the 
right pleura. On the left, at its commencement, is the left common caro- 
tid artery, separated from it by a triangular interval in which the trachea 
may be seen. It produces none but its terminal branches. 
The Right Common Carotid. 
The common carotid artery of the right side springs from the bifurca- 
tion of the arteria innominata, while the left common carotid is a branch 
of the arch of the aorta; consequently the left is as long as the right and 
the arteria innominata added together, and the relations of that portion 
corresponding to the arteria innominata will be similar to but not identi- 
cal with that vessel. From behind the left sterno-clavicular articulation 
to its termination a description of the left common carotid will apply to 
the right also. 
The right common carotid begins where the arteria innominata termi- 
nates, behind the upper border of the right sterno-clavicular articulation, 
and passes upward lying on the front of the anterior tubercles of the 
transverse processes of the cervical vertebrae, separated from them by the 
praevertebral group of muscles, as high as the fourth, or on a line with 
the upper border of the thyroid cartilage, where it terminates by dividing 
into the external and internal carotid arteries. In the female it usually 
terminates slightly below this level. 
Relations—The praevertebral group of muscles separates it from the 
anterior tubercles of the transverse processes of the cervical vertebrae 
as high as the fourth and the sympathetic nerve, with a ganglion on its 228 
Notes on Anatomy. 
upper portion, lies behind it on these muscles. It is contained in a strong 
fibrous sheath, which also contains the internal jugular vein, separated 
from the artery by a partition, and the pneumogastric nerve. The vein 
is external to the artery while the nerve lies behind and between the two. 
Descending on the front of the upper portion of the sheath is a nerve, 
called descendens noni, a branch of the hypoglossal, which sometimes 
pierces the sheath and descends within it. Just below the middle of the 
neck, about the central tendon of the omo-hyoid muscle, this nerve joins 
a branch from the second and third cervical called the communicans 
noni, forming Scarpa’s arch on the front of the sheath. To the inner 
side of the artery, separating it from its fellows of the opposite side, are, 
in the first part of its course the trachea, then the larynx and thyroid 
gland. These structures widen as the artery ascends, and the two arteries 
appear to be further apart and situated farther back above than below. 
The arteries are, however, more superficial above than below. The re- 
current laryngeal nerve crosses behind the artery making for its destina- 
tion, as does the inferior thyroid artery, a branch of the subclavian. The 
following structures cover the artery in front, in the order given : ist, 
integument; 2d, platysma myoides; 3d, sterno-cleido-mastoid; 4th, 
sterno-hyoid; sth, sterno thyroid; 6th, anterior belly of omo-hyoid. 
The platysma is an universal covering of the artery; the sterno-cleido- 
mastoid covers it from its commencement to within a short distance of its 
termination; the point where it draws off to the outer side corresponding 
to the point where the omo-hyoid crosses it, i. e., about the middle of 
the neck, opposite the cricoid cartilage where the artery enters the 
superior carotid triangle at its apex, emerging from beneath the anterior 
belly of the omo-hyoid and sterno-cleido-mastoid and passing up to 
about the middle of the triangle where it bifurcates. All that portion of 
the artery lying in the superior carotid triangle is superficial, being cov- 
ered only by the integument and platysma myoides. The sterno- 
hyoid and sterno-thyroid muscles cover only about; two inches of the 
artery, drawing off then to its inner side. At its origin the artery has in 
front the integument, fascia, platysma myoides, deep fascia, origin of the 
sterno-cleido-mastoid, the sterno-clavicular articulation of the right side 
and the origins of the sterno-hyoid and sterno-thyroid muscles. 
The course of the artery can be thus indicated; draw a transverse line 
from the upper border of the thyroid cartilage to the anterior edge of the 
sterno-cleido-mastoid muscle and a vertical line from the sterno-clavicu- 
lar articulation to the point where the transverse line intersects the sterno- 
cleido-mastoid, The artery will lie behind the vertical line. The Arteries. 
229 
The artery is preferably tied where it is crossed by the anterior belly 
of the omo-hyoid. The arch of Scarpa is found on the front of the sheath 
at this point. 
The common carotid is divided by surgeons into two portions. The 
first portion extending from its origin to the point where it is crossed by 
the omo-hyoid, the second, from this point to its termination. Some 
make three portions, the first lying in the inferior carotid triangle, the 
second being the part crossed by the anterior belly of the omo-hyoid, 
and the third lying in the superior carotid triangle. 
External Carotid. 
The external carotid artery, one of the two terminal branches of the 
common carotid, begins where that artery bifurcates about on a level with 
the upper border of the thyroid cartilage and, continuing the direction of 
the common carotid, passes beneath the posterior belly of the digastric 
and the stylo-hyoid muscles, enters the substance of the parotid gland 
and terminates in that gland behind the neck of the condyle of the lower 
jaw by dividing into two branches, the temporal and the internal maxil- 
lary arteries. The temporal continues the course of the external carotid 
to mount over the zygoma and be distributed to the side of the head by 
two branches, while the internal maxillary passes inward, behind the neck 
of the condyle of the lower jaw, to supply the deep structures of the 
face. 
The first portion of the external carotid lies in the superior carotid tri- 
angle, its length varying as the common carotid divides on a level with, 
above or below the upper border of the thyroid cartilage, for it extends 
from the bifurcation of the common carotid to the stylo-hyoid and pos- 
terior belly of the digastric. It is covered by the integument and platys- 
ma and is crossed in front by the hypoglossal or twelfth nerve. At its 
commencement the internal carotid lies to its outer side; but by the time 
the external carotid reaches the termination of its first portion, the inter- 
nal carotid has passed behind it. The second portion is that which is 
crossed by the stylo-hyoid and posterior belly of the digastric. Its cov- 
erings are integument, platysma, stylo hyoid and posterior belly of the 
digastric. The third and last portion extends from the stylo-hyoid and 
posterior belly of the digastric to the termination of the artery behind 
the neck of the condyle of the lower jaw. It lies embedded in the sub- 
stance of the parotid gland and is crossed, superficially, near its termina- 
tion, by the facial nerve. The first portion is most superficial, the second 
the shortest and the third the longest and deepest. 230 
Notes on Anatomy. 
Branches. 
SUPERIOR THYROID. 
LINGUAL. 
OCCIPITAL. 
POSTERIOR AURICULAR. 
ASCENDING PHARYNGEAL. 
FACIAL 
PAROTIDEAN. 
It should be remembered that the common carotid gives off no 
branches until it terminates, and hence the structures in its course have 
to be supplied by other arteries. The external carotid does a part of this 
work. Besides those into which it divides, the external carotid gives off 
six single branches, and a set to the parotid gland. The first three arise 
from the anterior aspect of the artery, low down and in the order given 
from below upward. The next two rise from the back of the artery 
higher up. 
I. Superior Thyroid 
The superior thyroid forms a curve, first passing upward and inward, 
then downward and inward, crossing beneath the depressor muscles of 
the hyoid bone, and reaches the upper part of the thyroid gland to which 
it is distributed. It gives off the following branches: 
ist. Hyoid, which passes forward just beneath the hyoid bone to be 
distributed to muscles. 
2d. Superior laryngeal, which passes forward on the thyro-hyoidean 
membrane and pierces it to be distributed to the mucous membrane of 
the larynx. 
3d. Inferior laryngeal, or crico-thyroid, which passes across the crico- 
thyroid membrane and gives branches which pierce it to reach the mucous 
membrane of the larynx. 
4th. Muscular or superficial descending branches, which passes down- 
ward and outward across the common carotid. 
11. Lingual. 
The lingual artery is divided into four portions: Ist, it descends ob- 
liquely inward, over the extremity of the hyoid bone covered only by 
the skin and platysma; 2d, it passes forward along and above the hyoid 
bone covered by the hyo-glossus muscle; 3d, it ascends to the under 
aspect of the tongue; 4th, it runs forward on the under aspect of the 
tongue, under the name of the ranine artery. The first two portions lie 
on the middle constrictor of the pharynx. Its branches are three: The Arteries. 
231 
ist. Hyoid, which runs inward along the upper border of the hyoid 
bone to be distributed to muscles. 
2d. Dorsalis lingualis, which ascends to the dorsum of the tongue 
along the posterior border of the hyo-glossus muscle. 
3d. Sublingual, which runs forward to the sublingual gland and to 
muscles. 
111. Facial. 
The facial artery arises just above the hyoid bone and is divided into 
two portions, one while it is in the neck and the other after it reaches the 
face. The first portion passes forward and upward, through the sub- 
maxillary gland, to mount over the body of the lower jaw just at the 
anterior inferior angle of the masseter muscle and about one and one-half 
inches in front of the angle of the lower jaw. At its origin it is super- 
ficial, being covered only by the skin and platysma; but. it soon enters 
the submaxillary gland and is crossed by the stylo-hyoid and posterior 
belly of the digastric. When it leaves the gland and mounts over the 
jaw it is again superficial, being covered only by the integument and 
platysma. Its pulsations can here be felt. The second portion of the 
artery has a tortuous upward and inward course over the face towards 
the angle of the mouth, thence along the side of the nose to terminate at 
the inner canthus of the eye as the angular artery. Its branches are 
divided into those given off below the jaw, five in number, and those on 
the face, also five in number. 
ist. Inferior palatine, which ascends to the soft palate. 
2d. Tonsillar, which ascends to the tonsils. 
3d. Submaxillary, which are from three to five in number and ascend 
to the submaxillary gland. 
4th. Submental, which runs forward beneath the lower jaw and pass- 
ing over the symphysis menti terminates by inosculating with the inferior 
labial. 
sth. Muscular branches distributed to neighboring muscles. 
The five branches from the second portion are as follows; 
ist. Muscular, or Buccal, which are branches to adjacent muscles. 
2d. Inferior labial, which runs forward beneath the lower lip. 
3d. Inferior coronary, which skirts the edge of the lower lip. 
4th. Superior coronary, which skirts the edge of the upper lip, giving 
off a branch to the septum of the nose, arteria septi. 
sth. Lateralis nasi, which is distributed to the side of the nose, inoscu- 
lating with its fellow of the opposite side. 232 
Notes on Anatomy. 
IV. Occipital. 
The occipital branch of the external carotid passes upward and back- 
ward to the occipital groove of the temporal bone, beneath the muscles 
attached to the mastoid process, thence mounting on the posterior aspect 
of the occipital bone and piercing some of the deep muscles of the back 
it becomes superficial and is distributed to the back of the head. Its 
branches are two: 
ist. Sterno-mastoid, which, sometimes arising directly from the exter- 
nal carotid, descends to muscles and glands. 
2d. Princeps cervicis, which passes down the neck lying deep. It in- 
osculates with the cervicalis ascendens from the subclavian and is of 
importance in establishing collateral circulation after ligation of the com- 
mon carotid. 
V. Posterior Auricular. 
The posterior auricular passes upward and backward behind the ear 
and is distributed by an anterior branch to the auricle and by a posterior 
to the back of the head. It produces one branch, the stylo-mastoid, 
which enters the stylo-mastoid foramen to be distributed to the ear. 
VI. Parotidean Branches. 
The parotidean branches, four or five in number, are distributed to the 
parotid gland as the external carotid is passing through it. 
Ascending Pharyngeal. 
The ascending pharyngeal branch springs from the external carotid 
just at its origin and passes up beside the pharynx to the base of the 
skull, where it divides into a meningeal branch to enter the cavity of the 
cranium through the jugular foramen, and a pharyngeal branch to ad- 
jacent parts. 
The Temporal Artery. 
The temporal artery, one of the two terminal branches of the external 
carotid, begins where the external carotid forks in the parotid gland, behind 
the neck of the condyle of the lower jaw, and emerging mounts over the 
zygoma and divides about one and one-half inches above that point, 
where it lies on the temporal fascia, into an anterior and a posterior tem- 
poral. The anterior passes upward and forward, the posterior upward The Arteries. 
233 
and backward to be distributed to the side of the head. These two are 
called the superficial temporal branches since, as will appear hereafter, 
there are other and deeper temporal branches. 
It gives rise to four branches besides those in which it terminates. 
ist. Transverse, facial which arises below the zygoma, and passes 
transversely forward on the masseter muscle parallel with Steno’s duct. 
2d. Anterior auricular, to the front of the auricle. 
3d. Orbital, which runs forward to the outer angle of the eye. 
4th. Middle temporal, which plunges into the substance of the tempo- 
ral muscle where it is distributed. Its name is derived from its situation 
between the two superficial temporal arteries and the deep which spring 
from another trunk. 
The Internal Maxillary. 
The internal maxillary is the larger of the two terminal branches of the 
external carotid. The course of the artery is divisible into three por- 
tions. The first portion passes inward, forward and upward behind the 
ramus of the inferior maxilla, between it and the internal lateral ligament. 
The second portion passes forward and upward between the internal 
pterygoid muscle within and the temporal and masseter muscle without. 
The third portion disappears into the spheno-maxillary fossa. Its 
branches are sixteen in number, as follows: 
First Portion—Four Branches. 
ist. Tympanic, which enters the tympanum through the fissure of 
Glaser. 
2d. Meningea media, which ascends to enter the cavity of the cranium 
through the foramen spinosum. 
3d. Meningea parva, which enters the cavity of the cranium through 
the foramen ovale. 
4th. Inferior dental, which descends to enter the dental foramen of the 
inferior maxilla and runs forward in the bone giving a branch to each fang 
of every tooth in the lower jaw. Just before entering the dental foramen it 
gives off a branch called mylo-hyoidean; and when it reaches the mental 
foramen it divides, sending a branch called mentalis through the mental 
foramen, while another, called the incisive, continues its course in the bone. 234 
Notes on Anatomy. 
Second Portion—Six Branches. 
These six branches are collectively known as the muscular branches 
and are distributed to the five muscles of mastication, each muscle receiv- 
ing one branch, except the temporal which has two, which, lying beneath 
the muscle on the bone, are known as the deep temporal arteries. 
Third Portion—Six Branches. 
ist. Superior dental, which descends upon the tuberosity of the supe- 
rior maxilla and sends its branches through small foramina in the bone to 
supply the teeth of the upper jaw. 
2d. Infra-orbital, which runs forward along the canal in the floor of 
the orbit, sending branches downward to the front teeth of the upper 
jaw and emerges through the infra-orbital foramen to supply adjacent 
parts on the face. 
3d. Spheno palatine, which enters the nose through the spheno-pala- 
tine foramen and divides into two branches, one being distributed to the 
septum and the other to the mucous membrane of the outer wall and an- 
trum maxillare. 
4th. Descending palatine, which descends along the posterior palatine 
canal to emerge in the palate through the posterior palatine foramen and 
send a branch forward in a groove seen on the side of the hard palate 
(called the anterior palatine canal) which reaches the floor of the nose 
through the anterior palatine foramen. 
sth. Pterygo-palatine, which runs backward in the pterygo-palatine 
canal to the pharynx, Eustachian tube and neighboring parts. 
6th. Vidian, which passes backward along the pterygoid canal and, 
like the preceding, is distributed to the mucous membrane of the pha- 
rynx and Eustachian tube. 
The Right Subclavian 
The right subclavian is the first subdivision of the artery of the upper 
extremity, which is known under three different names before it divides. 
It begins by being one of the terminal branches of the arteria innominata 
behind the upper border of the right sterno-clavicular articulation and 
arches outward forming a bow whose convexity is upward, first passing 
upward and outward, then outward to the top of the bow, and then down- 
ward and outward to pass obliquely beneath the clavicle and terminate at The Arteries. 
235 
the outer border of the first rib, beneath the junction of the outer one- 
third with the inner two-thirds of the clavicle by becoming the axillary 
artery. 
The top of the arch lies just behind the scalenus anticus muscle, a re- 
lation which warrants the division of the artery into three portions: the 
first portion extends from the origin of the artery upward and outward 
to the inner edge of the muscle; the second portion, the top of the bow, 
extends from there to the outer edge, or lies behind the scalenus anticus; 
the third portion passes downward and outward from the outer edge of 
the scalenus anticus to the termination of the artery. This portion may 
itself be divided into two parts, viz: that part which lies above the clav- 
icle and that which lies behind it. The third portion disappears beneath 
the clavicle about the middle of the bone, but its obliquity is so great that 
it emerges at the junction of the outer and middle thirds. 
Relations. 
Covering the artery universally are the integument, fascia and platysma 
myoides. In front of its origin are the structures which lie in front of the 
termination of the arteria innominata or the origin of the right common 
carotid, viz: integument, fascia, platysma, sterno-cleido-mastoid, sterno- 
clavicular articulation, sterno-hyoid and sterno-thyroid muscles. Owing 
to the outward direction of the artery the relation to these muscles is 
quickly lost. 
Lying to the inner side of the commencement of the artery is the 
right common carotid, and descending in the sheath with that vessel, the 
internal jugular vein is found, which crosses the front of the first portion 
and unites just beneath it with the subclavian vein to form the right vena 
innominata. The pneumogastric nerve, also lying to the outer side of 
the common carotid, crosses the front of the first portion, giving off, as 
it lies on the front, the right recurrent laryngeal which sweeps below and 
then winds up behind the artery, bearing the same relation to the subcla- 
vian that the left recurrent laryngeal does to the transverse part of the 
arch of the aorta. As the subclavian artery lies at the root of the neck, 
and the thoracic cavity lined by the pleura, extends one and one-half 
inches into the root of the neck, the pleura will be found lying below and 
behind the artery in all of its course until the two are separated by the 
first rib, on which the greater part of the third portion rests. 
A point of interest is the extent of the artery covered by the sterno- 
cleido-mastoid. This muscle usually covers the first and second portion; 236 
Notes on Anatomy. 
but, owing to the variations in its clavicular origin, it may barely cover 
the first two portions, or, having a redundant origin, it may cover all or 
a part of the third portion. 
The different parts studied separately: 
First Portion 
The first portion begins where the artery begins and passing upward 
and outward terminates in the second portion at the inner edge of the 
scalenus anticus muscle. It is covered throughout by the integument, 
platysma and sterno-cleido mastoid and at its commencement by the 
right sterno-clavicular articulation, the sterno-hyoid and sterno-thyroid 
muscles. Crossing its front are the pneumogastric and, generally, the 
phrenic nerves, though the latter sometimes crosses the second portion 
lying on the scalenus anticus, and the internal jugular vein, which, just 
as it has crossed the front of the artery, unites with the subclavian vein 
to form the right vena innominata!. The pneumogastric gives off, as it 
passes over the front, the recurrent laryngeal which bears a triple relation 
to the artery, viz ; behind, below and in front. 
To the inner side of the commencement is the right common carotid 
artery. 
Beneath the artery rests on the pleura, which extends up behind it. In 
this part of its course the artery has below it the subclavian vein, which 
forms a string to the subclavian bow, the vein running transversely inward 
behind the clavicle while the artery arches half an inch above it, and the 
two are in relation again only at the inner aspect of the termination of 
the artery. 
Second Portion. 
The second portion forms the top of the bow and runs transversely 
outward. It lies behind the scalenus anticus muscle and is coextensive 
with its breadth. 
In front are the integument, platysma, sterno-cleido-mastoid and sca- 
lenus anticus muscles, and occasionally the phrenic nerve. 
Behind and above it, separating it from the scalenus posticus, is the 
brachial plexus of nerves. 
Below and behind are the pleura. 
The subclavian vein is some distance below this portion, lying behind 
the clavicle and in front of the scalenus anticus muscle. The Arteries. 
237 
Third Portion. 
The third portion of the subclavian is the downward and outward por- 
tion, extending from the outer edge of the scalenus anticus muscle to the 
outer border of the first rib and lying first between the scaleni muscles 
and then between the clavicle and first rib. 
It is covered entirely by the platysma and possibly partially, or even 
totally, by a redundant origin of the sterno-cleido-mastoid muscle, while 
of course it is crossed by the clavicle. Crossing its front are two vessels, 
an artery and a vein. The supra-scapular artery, a branch of the sub- 
clavian itself, passes outward just beneath the upper border of the clavicle. 
The other vessel, the external jugular vein, descends the neck lying just 
behind the outer edge of the sterno-cleido-mastoid muscle, and, after 
receiving on the front, of the artery the supra-scapular and transverse 
cervical veins, terminates usually in the subclavian vein to the outer side 
of the scalenus anticus. To the outer side is the brachial plexus of 
nerves. To the inner side is the subclavian vein, which, however, is in 
contact only for a short distance from the termination of the artery. At 
its very commencement the pleura lies behind and below, but is soon cut 
off by the first rib. 
The subclavian is preferably ligated in the third portion where it is lying 
on the first rib, the clavicle being moved off by forcibly depressing the 
shoulder. This point is selected for the following reasons : it is most 
accessible; it is most remote from the branches of the artery; which all 
come from the first and second portions. It is separated from the pleura 
by the first rib. 
Branches 
VERTEBRAL. 
INFERIOR THYROID. 
SUPRA SCAPULAR. 
TRANSVERSA COLLI. 
INTERNAL MAMMARY. 
SUPERIOR INTERCOSTAL. 
CERVICALIS PROFUNDA 
These seven branches usually arise by four trunks, viz; the vertebral, 
thyroid axis, internal mammary and the common trunk for the superior 
intercostal and cervicalis profunda. 
The word “axis” in arterial anatomy means a short trunk which 
quickly divides into at least three branches. 
The branches which the thyroid axis produces are usually the inferior 
thyroid, supra-scapula and transversa colli though they vary greatly. 238 
Notes on Anatomy. 
The inferior thyroid is the most constant of its progeny and gives its 
name to the axis. 
I. Vertebral. 
The vertebral artery, the first and largest branch of the subclavian, 
arises from the posterior aspect of the artery and ascends through the 
foramina in the transverse processes of the cervical vertebrae—entering 
usually at the sixth and, winding backward around the superior articular 
process of the atlas, enters the cavity of the cranium through the foramen 
magnum and unites, at the lower border of the pons Varolii, with its fel- 
low of the opposite side to form a single trunk called the basilar artery, 
which runs forward to the anterior border of the pons where it divides 
into four terminal branches, two to each side. It gives off the following 
branches: 
ist. Lateral spinal, which are given off as the artery ascends the neck 
and enter the inter-vertebral foramina. 
2d, Muscular, unimportant branches to cervical muscles. 
3d. Posterior meningeal, also an unimportant branch to the dura mater 
of the cranium. 
4th. Anterior spinal, which unites with its fellow of the opposite side 
to form a common trunk which descends from the cranium along the 
front of the spinal cord. 
sth. Posterior spinal, which winds around the medulla oblongata to 
descend on the posterior aspect of the spinal cord. 
6th. Inferior cerebellar, which winds around the medulla oblongata to 
reach the under surface of the cerebellum. 
The branches of the basilar artery are as follows: 
ist. Transverse, which are numerous branches given off to each side 
of the pons Varolii. 
2d. Anterior cerebellar, which runs along the anterior border of the 
cerebellum and may be given as one of the transverse. 
The two terminal branches to each side are; 
3d. Superior cerebellar, which is distributed to the upper surface of 
the cerebellum. 
4th. Posterior cerebral, which is distributed to the posterior lobes of 
the cerebrum. 
Just as the basilar artery divides it gives off numerous small branches 
which enter the minute foramina constituting the locus perforatus of the 
base of the brain. The Arteries. 
239 
11. Inferior Thyroid. 
The inferior thyroid is the most constant branch of the thyroid axis, 
which arises from the upper aspect of the subclavian near the termination 
of its first portion. 
The inferior thyroid first ascends and then turns inward behind the 
sheath of the common carotid artery to reach the thyroid gland. Its 
branches are some unimportant twigs to the larynx, trachea and oesopha- 
gus and a large branch called the cervicalis ascendens, which arises from 
the inferior thyroid just as it makes its inward turn and ascends the neck 
on the anterior tubercles of the transverse processes to be distributed to 
muscles and glands. 
111. Supra-Scapular. 
The supra-scapular artery arises, usually, from the thyroid axis. It 
first descends and then turns outward behind the clavicle and, crossing 
the third portion of the subclavian, passes across the transverse ligament 
of the scapula to the dorsum of the scapula to be distributed there. 
IV. Transversa Colli. 
The transversa colli arises, usually, from the thyroid axis. It passes 
outward across the side of the neck to the anterior edge of the trapezius 
muscle where it divides into two branches, viz: the cervicalis superficialis, 
which ascends beneath the trapezius, and the posterior scapular, which 
passes to the scapula and descends along its base. 
V. Internal Mammary. 
The internal mammary arises from the under aspect of the subclavian 
and descending behind the costal cartilages, about half an inch from the 
edge of the sternum, to the diaphragm divides into two terminal branches, 
superior epigastric and musculo-phrenic. Its branches are as follows: 
ist. Anterior intercostal, which are given ofif to the intercostal spaces 
over which the internal mammary passes. Each, passing outward, soon 
divides into two branches to course along the adjacent borders of the 
ribs. Sometimes these branches spring separately from the artery. 
2d. Perforating, which—generally six in number—pass forward to the 
front of the thorax and run outward, being chiefly distributed to the 
mammary gland in the female. 240 
Notes on Anatomy. 
3d. Mediastinal, which are unimportant branches to the anterior medi- 
astinum. 
4th. Pericardiac, which are unimportant branches to the pericardium. 
sth. Comes nervi phrenici, which is a small branch to accompany the 
phrenic nerve. 
6th. Musculo-phrenic, one of the terminal branches, which passes out- 
ward and downward to the last intercostal space, behind the cartilages of 
the false ribs. 
7th. Superior epigastric, the other terminal branch, which enters the 
sheath of the rectus abdominis muscle and there anastomoses with the 
inferior epigastric, a branch which springs from the external iliac. This 
is the longest arterial anastomosis in the body and, taken in connection 
with the number of branches produced by the internal mammary, renders 
that artery the most remarkable in the body. 
VI. Superior Intercostal. 
The superior intercostal usually springs by a common trunk with the 
cervicalis profunda-from the second portion of the subclavian artery. It 
descends in front of the neck of the first rib and gives off branches to 
the first two intercostal spaces. 
VII. Cervicalis Profunda. 
The cervicalis profunda artery passes backward between the transverse 
processes of the seventh cervical vertebra and the first rib or transverse 
process of the first dorsal vertebra, and ascends the neck to inosculate 
with the princeps cervicis branch of the occipital artery, thus establishing 
collateral circulation in ligation of the common carotid. 
The Axillary Artery. 
The axillary is the second subdivision of the artery of the upper ex- 
tremity. Beginning where the subclavian ceases at the outer border of 
the first rib, it passes downward and outward over the upper lateral as- 
pect of the chest (the first four ribs) and down the inner aspect of the 
arm to terminate at the lower edge of the tendons of the latissimus dorsi 
and teres major muscles by becoming the brachial artery. The direction 
of that part of the artery on the arm varies of course with the movement 
of the limb. The Arteries. 
241 
Relations. 
It is covered throughout by the pectoralis major and beneath this it is 
crossed by the pectoralis minor. The latter relation warrants the sub- 
division of the artery into three portions. The first portion extends from 
the commencement of the artery to the upper edge of the pectoralis 
minor muscle, being contained in the triangular space between that mus- 
cle and the clavicle; the second lies beneath the pectoralis minor; the 
third extends from the lower edge of the pectoralis minor to the termina- 
tion of the artery. As the artery is crossing from the chest to the arm it lies 
on the tendon of the subscapularis and as soon as it strikes the inner side 
of the arm it lies along the inner side of the coraco-brachialis, which re- 
lation it maintains to its termination. 
The first portion of the axillary has the brachial plexus of nerves to 
its outer side and is covered by the pectoralis major. 
The second portion has the three cords which here make up the plexus 
one to its outer, one to its inner side and one behind it. It is covered in 
front by both the pectoral muscles and behind lies on the subscapularis. 
In the third portion the inner and outer cords each gives off a branch, 
the two uniting over the front of the artery to form the median nerve, 
which immediately drops off to the outer side of the artery where it 
remains to the termination of the vessel. This portion of the artery is 
covered in front only by the pectoralis major, while behind it lies on the 
tendons of the latissimus dorsi and teres major. Throughout the course 
of the artery the axillary vein lies continuously to its inner front aspect. 
Branches. 
SHORT THORACIC. 
ACROMIAL THORACIC, 
THORACICA ALARIS. 
LONG THORACIC. 
POSTERIOR CIRCUMFLEX. 
ANTERIOR CIRCUMFLEX. 
SUBSCAPULAR. 
The first two usually arise from the first portion of the axillary, the 
next two from the second portion, and the last three from the third por- 
tion. 
I. Short Thoracic. 
The short, or superior, thoracic arises from the first portion of the ax- 
illary and passes inward on the pectoralis minor muscle to be distributed 
to the pectoral muscles and mammary gland. 242 
Notes on Anatomy. 
11. Acromial Thoracic. 
The acromial thoracic arises from the first portion of the axillary by a 
short trunk which divides into the three following branches. 
ist. Pectoral, which supplies the pectoral muscles. 
2d. Acromial, which gives its name to the trunk though the smallest 
of its progeny, and passes outward to be distributed to parts around the 
acromion process. 
3d. Descending, which descends in the interspace between the deltoid 
and pectoralis major muscles. 
111. Thoracica Alaris. 
The thoracica alaris is a small branch given off from the second portion 
of the axillary to structures in the axilla. 
IV. Long Thoracic. 
The long thoracic artery arises from the second portion of the axillary 
and descends to supply the chest wall. It passes between the pectoral 
muscles and the serratus magnus and supplies both. 
V. Anterior Circumflex. 
The anterior circumflex artery arises from the third portion of the axil- 
lary, passes outward on the front of the humerus just below the shoulder 
joint, to which it is distributed, anostomosing externally with the poste- 
rior circumflex. 
VI. Posterior Circumflex 
The posterior circumflex artery springs from the third portion of the 
axillary, runs outward on the back of the humerus, is distributed to the 
shoulder joint and neighboring structures and inosculates with the ante- 
rior circumflex, the two forming a vascular zone around the upper ex- 
tremity of the humerus. The posterior is much the larger of the two. 
VII. Subscapular. 
The subscapular artery arises from the third portion of the axillary, 
and descends along the lower border of the subscapularis muscle to be The Arteries. 
distributed to adjacent parts. About an inch and a half from its origin it 
gives off a branch, the dorsalis scapulae, which mounts upon the dorsum 
of the scapular, to be there distributed. 
Brachial Artery. 
The brachial is the third subdivision of the artery of the upper ex- 
tremity. It begins by being a continuation of the axillary at the lower 
border of the tendons of the latissimus dorsi and teres major and passing 
downward and outward terminates half an inch, or a finger’s breadth, 
below the middle of the front of the elbow-joint by dividing into the 
ulnar and radial arteries. It lies first on the inner side of the arm and 
then on the front; so that in order to check the circulation by pressure, 
in the first part of its course the force must be directed outward and in 
the second part directly backward. 
Relations. 
The muscular relations are as follows : To its outer side, at first, is the 
lower half of the coraco-brachialis and when this relation is lost by the 
insertion of the muscle, its place is taken by the biceps, whose belly, 
when the muscle is bulky, overlaps the artery. At the bend of the elbow 
it lies beneath the slip given off by the biceps. In the first part of its 
course it lies on the internal intermuscular septum and in the lower part 
on the brachialis anticus. 
It is accompanied by satellite veins, one on either side, the one on the 
inner side being the larger. 
Its relations to cords are as follows: 
To its inner side are the basilic vein and the internal cutaneous nerve. 
The median nerve lies first to the outer side of the artery, then crosses 
it, usually in front, about the middle of the arm and remains a continu- 
ous internal relation. The internal cutaneous nerve and the basilic vein 
are superficial to the artery in the lower part of its course, lying between 
the layers of superficial fascia, while the artery lies beneath the deep fascia. 
Brachial at the Elbow. 
These relations are of such importance that they must be given sepa- 
rately. It lies on the middle of the front of the joint with a satellite vein 
on either side. On its outer side is the tendon of the biceps muscle; on 
its inner side the median nerve. In front of it is the bicipital fascia and 244 
Notes on Anatomy. 
lying on this are the median basilic vein and the internal cutaneous 
nerve. 
The brachial artery, once in five times, divides before reaching the 
point stated in this description. This is called high or premature division. 
When this is the case the ulnar artery continues the course of the brachial 
while the radial descends superficial to the ulnar. 
Branches. 
The branches are three in number, besides numerous twigs to muscles 
in its course collectively called muscular branches. 
I. Superior Profunda. 
The superior profunda arises from the upper part of the brachial and 
passes downward and outward, winding around the humerus, in the groove 
on its posterior face, to reach the outer aspect of the elbow joint where it 
lies in the interval between the supinator longus and the brachialis anti- 
cus muscles. 
11. Inferior Profunda. 
The inferior profunda artery arises from the brachial just below the 
superior and descends to the inner side of the elbow joint. 
111. Anastomotica Magna. 
The anastomotica magna runs inward from the brachial about two 
inches above the elbow and then runs outward on the back of the arm to 
the external condyle. 
Arteries of the Forearm. 
The arteries of the forearm are the radial and ulnar and their branches. 
Radial Artery on the Forearm. 
The radial artery, one of the two terminal branches of the brachial, 
begins where that artery divides about half an inch below the middle of 
the front of the elbow, and passes downward with such an inclination 
outward as to bring it to the outer side of the front of the wrist joint, 
where it lies on the front of the styloid process of the radius, terminating 
as the radial artery of the forearm by becoming the radial artery of the 
wrist. The Arteries. 
245 
Relations. 
To the outer side it has throughout its course the supinator longus, 
whose belly overlaps it. With this exception the artery is superficial. 
To its inner side is first the pronator radii teres, and, when that muscle is 
inserted, its place is taken by the flexor carpi radialis which remains to 
the inner side. 
It is accompanied by satellite veins, one on either side, and in the mid- 
dle third of its course has the radial nerve to its outer side. The nerve 
in the upper third is too far away to be considered a relation, while in the 
lower third it passes beneath the tendon of the supinator longus and dis- 
appears on the back of the forearm. 
Ulnar Artery on the Forearm. 
The ulnar artery, the larger of the two terminal branches of the brachial, 
begins where that artery terminates about half an inch below the middle 
of the front of the elbow, by dividing into itself and the radial, and passes 
first downward and inward for the upper third of its course, to the inner 
side of the front of the forearm and then turns vertically downward to 
reach the inner side of the front of the wrist, where it terminates as the 
ulnar artery of the forearm by becoming the ulnar artery of the hand. 
Relations. 
In the first part of its course, while it is passing downward and inward, 
it lies beneath four muscles, viz: pronator radii teres, flexor carpi radialis, 
palmaris longus and flexor sublimis digitorum—all the muscles of the 
superficial group except the flexor carpi ulnaris. When it emerges from 
beneath these muscles it descends with the tendon of the flexor carpi 
ulnaris to its inner and of the flexor sublimis digitorum to its outer side. 
It is accompanied by satellite veins, one to either side, and for its lower 
two-thirds has to its inner side the ulnar nerve. 
Ulnar Artery in the Hand. 
When the ulnar artery reaches the wrist it continues its course into the 
palm of the hand, lying close to and on the outer side of the pisiform 
bone and on the anterior annular ligament. After passing down a short 
distance into the palm, it turns outward and runs across the palm of the 
hand to its outer side, being covered only by the skin and fascia and 246 
Notes on Anatomy, 
lying on the flexor tendons. Its course across the palm is known as the 
superficial palmar arch (arcus sublimis) and though its direction is not 
transverse, it is more or less clearly defined by a transverse line across the 
palm drawn from the bottom of the internal between the thumb and in- 
dex finger. The ulnar nerve continues its relation to the artery in the 
hand, lying to its inner side. 
Branches. 
ANTERIOR ULNAR RECURRENT. 
POSTERIOR ULNAR RECURRENT. 
INTEROSSEOUS. 
MUSCULAR. 
I. Anterior Ulnar Recurrent. 
The anterior ulnar recurrent arises from the ulnar just below its origin 
and passes upward to the front of the inner side of the elbow. 
11. Posterior Ulnar Recurrent. 
The posterior ulnar recurrent rises just below the preceding and passes 
upward and backward to the internal condyle. 
111. Interosseous. 
The interosseous is a large trunk which arises from the ulnar just be- 
low the elbow and quickly forks into an anterior and posterior interos- 
seous. 
ist. The anterior interosseous descends on the front of the interosse- 
ous membrane, between the flexor profundus digitorum and flexor longus 
pollicis muscles, to the pronator quadratus, passing beneath which it 
perforates the interosseous membrane and appear on the back of the 
forearm to inosculate with the posterior interosseous artery. It supplies 
the muscles in its route and gives off a companion branch to the median 
nerve. 
2d. The posterior interosseous, as soon as it is produced, passes be- 
tween the bones above the interosseous membrane, to reach the back of 
the forearm and descend on the back of the interosseous membrane to 
the wrist. Just as it reaches the back of the forearm it gives off a large 
branch, called the posterior interosseous recurrent, which ascends to the 
back of the elbow. 
The posterior interosseous artery is distributed to adjacent muscles. The Arteries. 
247 
IV. Muscular. 
The muscular branches of the ulnar artery are numerous twigs to 
muscles in its course. 
Branches at the Wrist 
ANTERIOR CARPAL. 
POSTERIOR CARPAL. 
I. Anterior Carpal. 
The anterior carpal is a branch which passes outward on the front of 
the wrist to inosculate with the anterior carpal of the radial. 
11. Posterior Carpal. 
The posterior carpal passes backward and then runs outward on the 
back of the wrist to anastomose with the posterior carpal of the radial. 
These branches are very small and the anterior is frequently absent. 
Branches in the Hand 
COMMUNICATING 
DIGITAL. 
I. Communicating. 
The communicating branch dips between the abductor minimi digiti 
and flexor brevis minimi digiti to join the termination of the radial. 
11. Digital. 
The thumb and each of the fingers have two palmar arteries, one on 
either side, and two dorsal, similarly arranged, running from base to tip, 
called respectively palmar and dorsal collateral digital arteries. The 
digital arteries now under consideration are four in number, from the 
superficial palmar arch. The first is a small branch which supplies the 
inner side of the little finger; the second supplies adjacent sides of the 
little and ring fingers, splitting at the cleft between the two; the third 
does the same for adjacent sides of the middle and ring fingers and the 
fourth for adjacent sides of the middle and index fingers. 248 
Notes on Anatomy. 
Radial Artery of Wrist and Hand. 
When the radial artery reaches the wrist it turns outward, backward 
and downward beneath the extensor tendons of the thumb, viz: the ex- 
tensor ossis metacarpi pollicis, extensor primi and extensor secondi in- 
termodii pollicis, in the order named, and passing through what is known 
as the snuff box—the sunken interval between the extensor ossis meta- 
carpi pollicis and extensor primi internodii pollicis on one side and the 
extensor secundi internodii pollicis on the other—reaches the back of the 
hand where its appearance is only momentary, for it immediately dips 
into the palm of the hand by passing between the two heads of the first 
dorsal interosseous muscles, and, passing across the palm of the hand 
from the outer to the inner side, terminates by anastomosing with the 
communicating branch from the superficial palmar arch. The position 
of the radial in the palm is deep, lying on the-bases of the metacarpal 
bones and beneath the flexor tendons which separate it from the superfi- 
cial palmar arch. It is called the deep palmar arch and is situated about 
half an inch nearer the wrist than the superficial arch. 
Branches of the Forearm. 
RECURRENT RADIAL. 
MUSCULAR. 
I. Recurrent Radial. 
The recurrent radial arises from the radial just below the elbow and 
passes upward and outward to the outer side of the front of the joint. 
11. Muscular. 
The muscular branches are numerous twigs to muscles in the course of 
the artery. 
Branches at the Wrist 
SUPERFICIALIS VOL.E. 
ANTERIOR CARPAL. 
POSTERIOR CARPAL. 
DORSALIS POLLICIS. 
METACARPEA. 
DORSALIS INDICTS. 
PRINCEPS POLLICIS 
I. Superficialis Volae 
The superficial volae leaves the radial just as it turns outward and The Arteries. 
249 
passes to the muscles of the thenar group, usually perforating the abduc- 
tor pollicis. 
11. Anterior Carpal. 
The anterior carpal branch passes inward on the front of the joint to 
form the anterior carpal arch by uniting with the anterior carpal of the 
ulnar artery. 
111. Posterior Carpal. 
The posterior carpal passes inward across the back of the wrist to inos- 
culate with the posterior carpal of the ulnar and form the posterior car- 
pal arch. From the posterior carpal arch there pass down on the dorsal 
interosseous muscle two branches called posterior interosseous besides 
another which runs along the dorsal aspect of the ulnar border of the 
hand to supply the ulnar side of the dorsal aspect of the little finger. 
The posterior interosseous pass downward to divide the one at the cleft 
between the little and ring fingers to form dorsal collateral digital branches 
for the adjacent sides of those fingers, while the other performs a similar 
duty for the adjacent sides of the ring and middle fingers. 
IV. Dorsalis Pollicis. 
Just as the radial is passing the root of the thumb it gives off two 
small branches which course along the sides of the dorsal aspect of the 
thumb. They are called dorsalis pollicis. 
V. Metacarpea. 
The metacarpea is a branch which descends on the second dorsal inter- 
osseous muscle to the cleft between the middle and index fingers and 
there divides to form dorsal collateral digital branches for those fingers. 
VI. Dorsalis Indicis. 
The dorsalis indicis is a small branch which passes forward to form the 
dorsal collateral digital branch for the outer side of the index finger. 
VII. Princeps Pollicis. 
The princeps pollicis arises just as the radial dips into the palm of the 
hand and passes forward and outward to divide and form collateral digi- 
tal arteries for the palmar aspect of the thumb. 250 
Notes on Anatomy. 
Branches of the Deep Palmar Arch. 
RADIALIS INDICIS. 
ANTERIOR INTEROSSEOUS. 
I. Radialis Indicis. 
The radialis indicis passes forward to form the collateral digital branch 
for the palmar aspecr of the index finger. 
11. Anterior Interosseous 
The anterior interosseous are three or four small branches which pass 
forward on the front of the interosseous muscles to unite with the digital 
branches of the superficial arch. 
Besides these the deep arch gives off two sets of unimportant branches 
called perforating and recurrent. 
The Left Subclavian Artery. 
The left subclavian artery differs from the right in its first portion only, 
which extends from its origin to the inner edge of the scalenus anticus 
muscles. It arises as the last of the three branches from the arch of the 
aorta and passes almost perpendicularly to the inner edge of the scalenus 
anticus muscle and turns suddenly outward behind that muscle to pursue 
a course corresponding to that of the artery of the opposite side. 
Relations. 
In front of it is the confluence of the left internal jugular and left sub- 
clavian veins to form the left vena innominata; and the left pneumogastric 
and left phrenic nerves descend on its front into the thorax. To its inner 
side are the left common carotid artery and the trachea. Behind it is the 
thoracic duct. The pleura almost surrounds the artery, being in contact 
with it in front, behind and to the outer side. 
Branches of the Thoracic Aorta 
BRONCHIAL. 
MEDIASTINAL. 
INTERCOSTAL. 
PERICARDIAC. 
CESOPHAGEAL. 
I. Bronchial. 
The bronchial arteries, usually three to the left lung and one to the The Arteries. 
251 
right, course along the bronchi to the lungs and ramify with the bron- 
chial tubes. 
11. Intercostal. 
The intercostal are ten pairs of arteries which arise from both sides of 
the thoracic aorta and run out in the intercostal spaces, the upper inter- 
costal space being supplied by the superior intercostal of the subclavian. 
Each intercostal artery passes outward in the intercostal space to run 
along the lower border of the rib above and, after going some distance, 
give off a branch, which sinks to course along the upper border of the 
rib below. The intercostal arteries for the right side are longer than 
those of the left, owing to the position of the aorta which forces them to 
cross the vertebral column. 
These branches of the thoracic aorta are sometimes known as the pos- 
terior intercostal arteries to distinguish them from the anterior intercostals 
of the internal mammary and the superior of the subclavian. 
111. CEsophageal. 
The oesophageal are four or five small twigs which are successively 
furnished the oesophagus. 
IV and V. Mediastinal and Pericardiac 
These are small branches furnished to the posterior mediastinum and 
to the pericardium respectively. 
Branches of the Abdominal Aorta 
The branches of the abdominal aorta are nine in number, arranged in 
three sets, viz: those distributed to the abdominal wall and called parietal 
branches; those distributed to the abdominal viscera—the organs of 
digestion and those accessory thereto—and those distributed to the 
genito-urinary organs. There are three arteries in each of these sets, 
but some are double, i. e., one on each side. 
Parietal Branches. 
PHRENIC. 
SACRA MEDIA. 
LUMBAR. 
I. Phrenic Arteries. 
The phrenic are a pair of small arteries arising from the aorta soon 252 
Notes on Anatomy. 
after it enters the abdomen, sometimes singly, sometimes by a common 
trunk and sometimes from neighboring arteries. Each artery runs up- 
ward and outward on the under surface of the diaphragm and is there 
distributed by two branches, one passing inward to inosculate over the 
oesophageal opening with the opposite one, while the other runs outward 
to supply the circumference of the diaphragm. 
11. Lumbar Arteries 
The lumbar arteries are four or five pairs of small branches which 
spring successively from the back of the aorta and run outward to ramify 
in the broad muscles of the abdomen, resembling the intercostal branches 
of the thoracic aorta. 
111. Sacra Media. 
The sacra media is a small slender artery which arises just at the foot 
of the aorta, or sometimes from one of its fork, and runs down on the 
front of the sacrum to the coccyx. 
Visceral Branches. 
CCELIAC AXIS. SUPERIOR MESENTERIC. 
INFERIOR MESENTERIC. 
Coeliac Axis. 
The coeliac axis is a short trunk about one-half an inch in length, which 
arises from the front of the abdominal aorta near its commencement. It 
runs directly forward from the front of the abdominal aorta. Below it is 
the head of the pancreas upon which it rests; in front is the lesser omen- 
tum; above and to the right is the lobus Spigelii. The semilunar ganglia 
lie upon its sides, while the solar plexus of nerves surround the artery. 
Its branches are three, gastric, splenic, and hepatic. 
i. The Gastric Artery. 
The gastric artery passes to the left to reach the cardiac end of the 
stomach and then turns to the right to run along the lesser curvature 
to near the pylorus where it inosculates with the pyloric branch of the 
hepatic artery. It distributes branches to both sides of the stomach. The Arteries. 
2. The Splenic Artery. 
The splenic artery passes tortuously to the left along the upper border 
of the pancreas to the hilum of the spleen where it splits into numerous 
branches to be distributed to that organ. Its branches are as follows: 
(a) Pancreatic, numerous small branches which descend into the pan- 
creas as the splenic artery is coursing along its upper border. 
Cb) Vasa brevia, five or six branches which leave the splenic artery 
near its terminal branches and pass to the splenic end of the stomach. 
(V) Gastro-epiploica sinistra, the left gastro-epiploic, a large branch 
which leaves the splenic artery near the spleen and runs to the right along 
the greater curvature of the stomach until it meets the right gastro-epi- 
ploic about the middle of that curvature. It gives off ascending branches 
to both faces of the stomach and descending branches to the great omen- 
tum. 
3, The Hepatic Artery. 
The hepatic is a large branch which passes upward and to the right to 
the under surface of the liver where it divides into three branches, one to 
each lobe of the liver and a third called the cystic which is distributed to 
the coats of the gall-bladder. Besides its three terminal branches the 
hepatic artery produces two others. 
(a) The pyloric branch passes to the left along the lesser curvature of 
the stomach until it meets the gastric artery, being distributed to both 
faces of the stomach. 
Cb) The gastro duodenalis is a large branch which descends from the 
hepatic behind the pancreas and divides into two branches. 
Ist. Pancreatico-duodenalis superior which descends between the pan- 
creas and duodenum and is there distributed. 
2d. Gastro-epiploica dextra, which passes to the left along the greater 
curvature of the stomach to meet the gastro-epiploica sinistra, a branch 
of the splenic. 
11. Superior Mesenteric Artery 
The superior mesenteric is a large artery which arises from the front 
of the aorta iust below the coeliac axis and behind the head of the pan- 
creas. It descends between the lower border of the pancreas and the 
transverse duodenum to reach the right iliac fossa, presenting in its course 
a curve whose convexity is to the left, and lying between the layers of the 
mesentery. 254 
Notes on Anatomy. 
Branches, 
Besides a small branch called pancreatico-duodenalis inferior, which 
ascends between the head of the pancreas and the duodenum, the branches 
of the superior mesenteric are as follows: 
i. Vasa Intestini Tenuis. 
Arising successively from the convex aspect of the superior mesenteric 
artery are fifteen or twenty branches which are distributed to the small 
intestine from the duodenum to near the ileo-ccecal aperture. They are 
called vasa intestini tenuis. After running a short distance these branches 
divide and unite with adjacent ones, forming arches from which spring 
other branches which in turn unite to form a second series of arches; and 
from these spring another set of branches which form the third series of 
arches from which straight vessels pass out to supply both faces of the 
gut. 
2. Ileo-Colic Artery. 
The ileo-colic is the lowest of the three branches given off from the 
concave aspect of the superior mesenteric and is distributed to the ter- 
mination of the ileum and beginning of the large intestine. 
3. Colica Dextra, 
The colica dextra is the middle of the three branches arising from the 
right side of the superior mesenteric and is distributed to the ascending 
colon. 
4. Colica Media. 
The colica media is the first of the three arteries which arise from the 
right aspect of the superior mesenteric. It turns upward and is distri- 
buted to the right half of the transverse colon and to the termination of 
the ascending colon. All these branches of the superior mesenteric 
anastomose with each other successively in the order in which they are 
given off, and the colica media anastomose with the colica sinistra branch 
of the inferior mesenteric. 
111. Inferior Mesentric. 
The inferior mesenteric, smaller than the superior, arises from the front 
of the aorta near its termination and descends obliquely to the left iliac 
fossa, giving off the following branches; The Arteries. 
255 
i. Colica Sinistra. 
The colica sinistra passes downward and to the left, and divides into 
two branches, one of which is distributed to the descending colon, while 
the other ascends to supply the left half of the transverse colon and inos- 
culate with the colica media branch of the superior mesenteric. 
2. Sigmoideal. 
The sigmoideal are several branches distributed to the sigmoid flexure 
of the colon. 
3. Superior Hemorrhoidal 
The superior hemorrhoidal is the continuation of the inferior mesenteric. 
It descends along the posterior aspect of the rectum to about its middle, 
where it divides, being distributed to the rectum. 
The branches of the inferior mesenteric anastomose with each other 
and its colica sinistra branch anastomoses with the colica media of the 
superior mesenteric. 
SUMMARY. 
The stomach is supplied with blood by the following arteries: the lesser 
curvature by the gastric artery and the pyloric branch of the hepatic; 
the greater curvature by the right gastro-epiploic for its right half and 
the left gastro-epiploic for its left half; the former being a branch of the 
gastro-duodenalis, a branch of the hepatic, and the latter a branch of the 
splenic. The splenic end of the stomach is supplied by the vasa brevia 
of the splenic artery. 
The duodenum is chiefly supplied by the pancreatico-duodenalis supe- 
rior branch of the gastro-duodenalis of the hepatic. 
The small intestine, from the duodenum to near the large intestine, is 
supplied by the vasa intestini tenuis of the superior mesenteric. The 
termination of the small intestine and the commencement of the large are 
supplied by the ileo-colic branch of the superior mesenteric. The as- 
cending colon is supplied by the colica dextra, and the right half of the 
transverse colon by the colica media branch of the same artery. The 
left half of the transverse colon and the descending colon are supplied by 
the colica sinistra of the inferior mesenteric. The sigmoid flexure is sup- 
plied by the sigmoidal branches, and the upper half of the rectum by the 
superior hemorrhoidal branch from the inferior mesenteric. 256 
Notes on Anatomy. 
Genito-Urinary Branches. 
SPERMATIC. 
SUPRA-RENAL. 
RENAL. 
Spermatic Arteries. 
The spermatic are a pair of small arteries which arise from the front of 
the aorta and descend behind the peritoneum to the brim of the pelvis, 
one on each side. In the male the artery passes then to the internal ab- 
dominal ring, and accompanies the other elements of the cord to the 
testicle. In the female this artery is known as the ovarian, and is ex- 
pended on the ovaries and Fallopian tubes. 
Renal Arteries. 
Each renal artery arises from the side of the aorta and passes outward 
to be distributed to the kidney. The left renal artery is somewhat higher 
than the right owing to the relative position of the two kidneys. 
Supra-Renal Arteries. 
The supra-renal are a pair of small arteries which arise from the side 
of the aorta about the origin of the renal arteries and pass out, one on 
either side, to be distributed to the supra-renal capsule. 
Common Iliac Arteries. 
The common, or primitive, iliac artery of each side begins where the 
abdominal aorta bifurcates at the left side of the lower border of the body 
of the fourth lumbar vertebra, as a rule, though the exact point of divi- 
sion may vary as much as an inch. From this point the common iliac 
passes downward and outward to the brim of the pelvis, where it termi- 
nates on the side of the disk between the fifth lumbar vertebra and the 
sacrum by dividing into the external and internal iliac arteries. The 
right artery is slightly the longer, the average length of each being about 
two inches. 
Relations Right Common Iliac 
The right common iliac is crossed in front, near its termination, by the 
right ureter. To its outer side is the psoas magnus muscle. Behind and The Arteries. 
257 
somewhat external is the right common iliac vein and crossing behind it 
is the left common iliac vein. 
Relations Left Common Iliac. 
The left common iliac is crossed in front by the sigmoid flexure of the 
colon, by the superior hemorrhoidal artery and by the left ureter, near its 
termination. External to it is the psoas magnus muscle. Its vein is be- 
hind and internal to it. It is thus seen that each vein is more or less to 
the right of its artery and behind, the left vein being forced to cross be- 
hind the right artery in order to unite with the right vein to form the 
inferior vena cava, which lies to the right of the aorta. 
Internal Iliac Artery. 
The internal iliac artery, one of the two terminal branches of the com- 
mon iliac, begins where that artery forks, on the brim of the pelvis on the 
disk between the fifth lumbar vertebra and the sacrum and descends into 
the pelvis on the front of the sacro-iliac symphysis to the upper margin 
of the great sacro-sciatic notch, and there divides into an anterior and a 
posterior trunk. The artery varies in length from an inch to two inches. 
The only relation besides those given is that the vein is immediately be- 
hind it. 
The distribution of the internal iliac is to the viscera and walls of the 
pelvis; and it will be found, with trifling exceptions, that the parietal 
branches spring from the posterior trunk while the visceral are the off- 
spring of the anterior. It should be remembered that the hypogastric 
artery of the foetus is a branch of the internal iliac; passing from it up- 
ward and inward to the bladder and up beside it to reach the umbilicus 
after coursing along the posterior aspect of the anterior abdominal wall, 
and that after birth it is impervious from the umbilicus as far back as the 
side of the bladder, but from this point to its origin it remains open and 
gives origin to some arteries which supply the bladder, viz; those which 
supply its upper and middle portions, called the superior and middle 
vesical arteries. 258 
Notes on Anatomy. 
Branches of the Anterior Trunk 
HYPOGASTRIC. 
INFERIOR VESICAL. 
MIDDLE HEMORRHOIDAL. 
OBTURATOR. 
ISCHIATIC. 
INTERNAL PUDIC. 
Inferior Vesical 
The inferior vesical is distributed to the base of the bladder and, in 
the male, also to the prostate gland and seminal vesicles. 
Middle Hemorrhoidal. 
The middle Hemorrhoidal artery aids in supplying the rectum and de- 
rives its name from the fact that there are two other hemorrhoidal arteries, 
one supplying the upper and one the lower part of the gut, while this 
takes the intermediate portion. 
Besides these two branches, there are some peculiar to the female, viz; 
vaginal, to supply the vagina, and uterine to the uterus. 
Obturator. 
The obturator artery passes forward along the wall of the pelvis just 
below the brim and escapes through the upper part of the obturator fora- 
men to divide into an internal and an external branch which are distribu- 
ted around the front of the obturator foramen. The obturator artery is 
frequently a branch from the posterior trunk, and once in three dissections 
will be found descending to the obturator foramen from the epigastric 
branch of the external iliac. 
After giving off the foregoing branches the anterior trunk divides into 
two branches, the ischiatic or sciatic and the internal pudic. 
Ischiatic Artery. 
The ischiatic artery, one of the two terminal branches of the anterior 
trunk of the internal iliac, leaves the pelvis through the greater sacro- 
sciatic foramen below the pyriformis muscle and descending between the 
trochanter major and the tuberosity of the ischium breaks into numerous 
branches, most of which are muscular. 
Internal Pudic. 
The internal pudic artery, the second of the two terminal branches of The Arteries. 
259 
the anterior trunk of the internal iliac, leaves the pelvis through the 
greater sacro-sciatic foramen below the pyriformis muscle, and passing 
across the spine of the ischium re-enters the pelvis through the lesser 
sacro-sciatic foramen and runs forward and upward about an inch above 
the lower edge of the tuber ischii, and then along the inner aspect of the 
rami of the ischium and pubes towards the symphysis pubis. 
Branches. 
Inferior Hemorrhoidal. 
The inferior hemorrhoidal are several small branches given to the anus 
as the internal pudic is passing near it. 
Superficial Perineal. 
The superficial perineal passes forward through the perineum as far as 
the scrotum and in its course gives off the transversus perinaei branch 
which crosses the perineum. 
The Artery of the Bulb 
The artery of the bulb enters the bulb of the corpus spongiosum and 
is there distributed. 
Artery of the Corpus Cavernosum. 
The artery of the corpus cavernosum enters the crus penis and is dis- 
tributed to the corpus cavernosum. 
Dorsal Artery of the Penis 
The dorsal artery of the penis runs along the dorsum of the penis as 
far as the glans. 
Branches of the Posterior Trunk 
LATERAL SACRAL. 
GLUTEAL. 
ILIO-LUMBAR. 
Lateral Sacral Arteries. 
The lateral sacral are a pair of small arteries the superior of 
which enters the first anterior sacral foramen and the inferior passes down 
on the side of the front of the sacrum and sends a branch into each an- 
terior sacral foramen except the first. 260 
Notes on Anatomy. 
Ilio-Lumbar' Artery. 
The ilio-lumbar is a recurrent branch which ascends beneath the ex- 
ternal iliac artery and divides into two branches, one of which continues 
upward to the psoas magnus and quadratus lumborum muscles, while the 
other turns outward. 
Gluteal Artery 
The gluteal artery is the continuation of the posterior trunk of the in- 
ternal iliac. It passes backward through the upper part of the great 
sacro-sciatic foramen above the pyriformis muscle and divides into three 
branches, a superficial which is distributed between the gluteus maximus 
and gluteus medius muscles and two deep branches which lie between the 
gluteus medius and minimus. 
External Iliac Artery. 
The external iliac begins where the common iliac forks into it and the 
internal iliac on the side of the disk between the fifth lumbar vertebra 
and the sacrum and continues the course of its parent downward and 
outward to enter the thigh and become the femoral artery by passing 
beneath Poupart’s ligament at a point midway between the anterior supe- 
rior spinous process of the ilium and the symphysis pubis. Its course 
and that of the common iliac may be indicated by drawing a line from a 
point just to the left of the umbilicus, which corresponds to the bifurca- 
tion of the aorta, downward to a point half way between the anterior 
superior spinous process of the ilium and the symphysis pubis. 
Relations. 
To the outer side of the artery is the psoas magnus muscle separated 
from it by the iliac fascia which throws a covering over them. In front 
is the peritoneum and some fascia. Each artery is accompanied by a 
vein, the relation to which is different on the two sides. The vein of the 
left side is internal throughout; that of the right is first behind and ex- 
ternal, then behind and then internal and abreast, so that at Poupart’s 
ligament each vein is internal to and fully abreast of its artery. The Arteries. 
261 
Branches. 
EPIGASTRIC. 
CIRCUMFLEX ILIAC. 
Epigastric Artery 
The epigastric artery arises from the inner side of the external iliac 
near Poupart’s ligament and runs upward and inward on the posterior 
face of the anterior abdominal wall, lying just beneath the peritoneum 
and transversalis fascia, which it raises into a ridge and enters the sheath 
of the rectus muscle, where it anastomoses with the inferior epigastric 
branch of the internal mammary, thus forming the most remarkable 
anastomosis in the body. Soon after its origin the epigastric artery gives 
off a communicating branch which descends to the obturator artery, and, 
indeed, sometimes supplies the place of that artery. 
Circumflex Iliac Artery. 
The circumflex iliac arises from the outer side of the external iliac just 
above Poupart’s ligament and passes upward and outward along the crest 
of the ilium and about the middle of it gives off a large branch which is 
distributed between the internal oblique and transversalis muscles. 
The Femoral Artery. 
The femoral artery is the continuation of the external iliac, commencing 
where that artery terminates, beneath Poupart’s ligament, at a point mid- 
way between the anterior superior spinous process of the ilium and the 
symphysis pubis, where it can be felt pulsating, it descends the front of 
the thigh to its lower third, where it pierces the insertion of the adductor 
magnus muscle to reach the back of the thigh and become the popliteal. 
As long as it lies on the front of the thigh, that is, for the upper two- 
thirds of its course, it is known as the femoral artery; as soon as it 
reaches the lower third and appears on the back of the thigh it is called 
popliteal. 
A line drawn from about the middle of Poupart’s ligament to the inner 
aspect of the internal condyle will indicate the course of the femoral 
artery, which lies behind the upper two-thirds of the line. 
Relations. 
For the first half or third of its course the femoral artery is superficial, 262 
Notes on Anatomy. 
lying in Scarpa’s triangle, having the sartorius to its outer side and the 
adductor longus to its inner side. It enters the triangle about the middle 
of the base and passing through the centre leaves it usually about at its 
apex by passing beneath the sartorius. It then descends, lying on the 
front of the insertion of the adductor longus, which relation it maintains 
to within about an inch or so of its termination, and for that distance it is 
separated from the posterior face of the sartorius by a tendinous arch 
which the adductor longus and adductor magnus throw over the artery 
to the vastus internus; so that the last inch or two of the femoral artery 
is the deepest portion, being covered by the skin, superficial fascia, fascia 
lata, sartorius and the tendinous arch above mentioned. Throughout its 
course the artery lies between the sartorius and adductor longus. 
In the upper part of its course these muscles lie one on either side, 
while below the sartorius is in front and the adductor longus behind. 
For the last inch or two the sartorius is separated from the artery by the 
tendinous arch. 
Relation to cords: It lies in a sheath which also contains the femoral 
vein. At Poupart’s ligament the vein is internal and abreast of the 
artery, but as it descends it gradually gets behind the artery and then 
external. For the first few inches of its course the artery has from one- 
fourth to one-half an inch to its outer side the anterior crural nerve 
which here divides into numerous branches, some of which cross 
in front of the artery, while one, the long saphenous, descends 
to its outer side until it reaches Hunter’s canal when it gets in 
front. It is not in the sheath of the artery. From one to two inches 
below Poupart’s ligament the artery gives off a large branch, the deep 
femoral. At first this branch is external to the femoral, but it quickly 
passes behind, remaining a posterior relation until they are separated by 
the adductor longus muscle. Between the two arteries are interposed 
the corresponding veins, the femoral vein being in front. 
Branches. 
SUPERFICIAL EPIGASTRIC. 
SUPERFICIAL CIRCUMFLEX ILIAC. 
SUPERFICIAL EXTERNAL PUDIC. 
DEEP EXTERNAL PUDIC. 
PROFUNDA FEMORIS. 
ANASTOMOTIC MAGNA. 
MUSCULAR. 
Soon after its commencement the femoral artery gives off four small 
branches which are all cutaneous. They are the first four named above. The Arteries. 
263 
Superficial Epigastric. 
The superficial epigastric passes upward and inward toward the um- 
bilicus lying beneath the skin and superficial fascia. 
Superficial Circumflex Iliac. 
The superficial circumflex iliac runs upward and outward along the 
crest of the ilium. 
Superficial External Pudic 
The superficial external pudic passes inward in front of the femoral 
vein towards the genital organs. 
Deep External Pudic 
The deep external pudic runs inward behind the femoral vein to be 
distributed to the integument of the external organs of generation. 
Profunda Femoris. 
At a variable distance from its commencement, generally from one to 
two inches though sometimes less and sometimes more, the femoral 
artery gives off from its outer posterior aspect a branch called the pro- 
funda femoris which is almost as large as the continuation of the femoral 
itself. The direction of the profunda is for a short distance downward 
and outward, then curving inward, almost immediately after its origin, it 
descends vertically lying behind the femoral artery and having no muscle 
interposed between them until the two reach the upper edge of the ad- 
ductor longus which muscle thence forward separates them, the femoral 
passing down on its front and the profunda behind it for some distance 
and then, perforating the adductor magnus, passes to the back of the 
thigh where it is distributed. 
The profunda artery is contained in a sheath in which lies also its vein, 
which is in front of the artery. As the profunda descends behind the 
femoral it is separated from it by two veins, profunda and femoral; so that 
from the origin of the profunda down to the adductor longus muscle, the 
structures lie in the following order from before backward: femoral artery, 
femoral vein, profunda vein, profunda artery. 264 
Notes on Anatomy. 
Branches of the Profunda. 
EXTERNAL CIRCUMFLEX. 
INTERNAL CIRCUMFLEX. 
THREE PERFORATING. 
External Circumflex. 
The external circumflex arises early from the profunda and passes 
outward around the upper extremity of the femur, giving off two sets of 
branches, one ascending to the gluteal region and the other descending 
to the outer aspect of the thigh and knee-joint. 
Internal Circumflex. 
The internal circumflex arises from the profunda near its commence- 
ment and is much smaller than the external circumflex. It passes inward 
around the upper extremity of the femur and anastomoses with the ex- 
ternal. 
The Three Perforating Arteries. 
As the profunda femoris is descending it gives off in succession three 
branches, each called perforating, superior, middle and inferior. They 
derive their names from the fact that they perforate the adductor mag- 
nus muscle (the superior perforating the adductor brevis also) to reach 
the back of the thigh and supply the posterior femoral muscles. 
Anastomotica Magna. 
The anastomotica magna, the last branch of the femoral artery, arises 
from it just as that artery is about to pierce the adductor magnus and 
descends toward the knee after dividing into a superficial and a deep 
branch. 
Besides the six foregoing branches the femoral artery gives off mus- 
cular branches to the muscles in its course. 
The Popliteal Artery. 
The popliteal artery is the continuation of the femoral. It begins 
where that artery terminates by piercing the insertion of the adductor 
magnus at the junction of the middle and lower thirds of the thigh, to 
appear on the back of the thigh, and passes downward and outward 
(the outward inclination being greatest at first) through the popliteal The Arteries. 
265 
space, to terminate at the lower border of the popliteus muscle, where it 
is passing beneath the tendinous arch of the soleus, by dividing into the 
anterior and posterior tibial arteries. 
The artery rests successively on the posterior aspect of the femur, the 
posterior ligament of the knee-joint and the popliteal fascia which sepa- 
rates it from the popliteus muscle. It is surrounded by the mass of fat 
which fills the popliteal space. On its outer side it has above the tendon 
of the biceps and below the outer head of the gastrocnemius. On the 
inner side are the internal hamstring muscles and the inner head of the 
gastrocnemius. 
Relations to Cords 
The artery is accompanied by the popliteal vein and the internal pop- 
liteal nerve. The artery is the deepest of the three cords; next it and 
hugging it closely is the vein, which is external to the artery as well as 
superficial; while the nerve is the most superficial and is somewhat ex- 
ternal to the vein separated from it by some fat. When the artery 
reaches the commencement of the lower third of its course these rela- 
tions change, for here the vein and nerve cross superficially to its inner 
side, where they remain to the termination of the artery. 
At the commencement both the artery and vein lie some distance to 
the inner side of the internal popliteal nerve, because the nerve enters 
the space at its superior apex while the artery and vein enter some little 
distance down on the inner side; but since the vein and artery have an 
outward inclination and the nerve slightly the opposite they soon come 
into close relation. The internal popliteal nerve is one of the terminal 
branches of the great sciatic which descends the middle of the back of 
the thigh and divides at the popliteal space sending its other branch, the 
external popliteal, downward along the outer side of the space. 
Branches. 
SUPERIOR EXTERNAL ARTICULAR. 
SUPERIOR INTERNAL ARTICULAR. 
AZYGOS ARTICULAR. 
INFERIOR EXTERNAL ARTICULAR. 
INFERIOR INTERNAL ARTICULAR. 
MUSCULAR. 
The superior articular arteries surround the low'er extremity of the 
femur just above the knee, the external passing beneath the tendon of the 
biceps and the internal beneath the adductor magnus. 
The inferior articular arteries surround the upper extremity of the 
tibia just below the knee. 266 
Notes on Anatomy. 
The azygos articular is a single branch which perforates the posterior 
ligament to enter the knee-joint. 
The muscular branches are divided into two sets, superior muscular, 
distributed to the hamstring muscles, and inferior muscular, or sural, dis- 
tributed to the gastrocnemius. 
The Posterior Tibial Artery 
The posterior tibial artery, one of the two terminal branches of the 
popliteal, begins where that artery terminates at the lower border of the 
popliteus muscle, beneath tne tendinous arch of the soleus and descends 
the back of the leg with a steady inclination inward to the inner aspect 
of the os calcis where it divides, between the internal malleolus and tendo 
Achilles into the internal and external plantar arteries. 
Relations. 
The posterior tibial artery for about the upper two-thirds of its course 
lies deep, covered by the triceps surse, but for the rest of its course it is 
superficial, having emerged to the inner side of the tendo Achilles, be- 
cause of its own inward inclination and because of the narrowing of the 
triceps surae to a tendon. 
The artery is accompanied by satellite veins and by the posterior tibial 
nerve. The nerve for the first few inches of the artery (to the lower 
part of the upper third of the leg) lies to the inner side of the artery and 
then crosses it posteriorly to assume a continuous external relation. The 
nerve crosses about where the peroneal branch arises. 
Branches 
PERONEAL. 
TERMINAL. 
INTERNAL CALCANEAN. 
Besides muscular branches to the muscles in its course, and its two ter- 
minal branches, the posterior tibial produces two branches, peroneal and 
internal calcanean. One of its earliest muscular branches gives off a 
recurrent branch which passes upward to the knee-joint. 
I. Peroneal Artery. 
The peroneal artery is nearly as large as the continuation of the pos- 
terior tibial, and arises from that artery high up, near its origin, the dis- 
tance being about two inches. It first passes obliquely downward and The Arteries. 
267 
outward to the origin of the flexor Jongus poilicis muscle and then de- 
scends vertically beneath that muscle to terminate on the outer side of 
the os calcis. 
Relations. 
The peroneal in the upper, oblique, part of its course is covered, like 
its parent, by the triceps surge muscle, but after reaching the flexor lon- 
gus poilicis it is covered by that muscle in addition. In the lower part 
of the leg the difference between the two arteries in depth is very con- 
siderable, since the posterior tibial is here superficial while the peroneal 
is still covered by the flexor longus poilicis and the tendo Achilles. 
Branches. 
Just above the posterior tuberosity of the os calcis the peroneal and 
posterior tibial arteries are connected by a small transverse communica- 
ting branch. The peroneal gives muscular branches to the muscles in its 
course. About the lower third of the leg the peroneal gives off a large 
branch called the anterior peroneal which pierces the interosseous mem- 
brane to reach the front of the leg. The termination of the peroneal is 
distributed on the outer side of the heel by branches called external cal- 
canean. 
11. Internal Calcanean Branches. 
The internal calcanean branches of the posterior tibial are three or 
four in number and are distributed to the inner side of the heel. 
The Internal Plantar Artery. 
The internal plantar, much the smaller of the two terminal branches of 
the posterior tibial, begins where that artery bifurcates midway between 
the posterior tuberosity of the os calcis, and the internal malleolus and 
passes forward along the inner side of the sole to terminate on the inner 
side of the great toe having given off muscular branches in its course. 
The External Plantar Artery. 
The external plantar, the larger and more important of the two termi- 
nal branches of the posterior tibial, begins where that artery bifurcates 
midway between the posterior tuberosity of the os calcis and the internal 
malleolus, and passes forward and outward between the first and second 
layers of muscles in the sole to the base of the fifth metatarsal bone where 268 
Notes on Anatomy. 
it turns inward beneath the third layer of the muscles to cross to the inner 
side of the sole and terminate there at the posterior extremity of the first 
interosseous space by anastomizing with a communicating branch from 
the dorsalis pedis artery. That portion of the artery which crosses the 
sole from the outer to the inner side is called the plantar arch. 
Branches. 
Besides muscular branches, the external plantar gives off the following: 
digital and posterior perforating. 
I. Digital. 
The digital branches are four in number. They run forward to the 
cleft between the toes and there divide to supply plantar collateral 
branches to the sides of the toes, except the great toe and the inner side 
of the second toe. The outermost of the four is appropriated by the 
outer side of the little toe. Just before the digital arteries divide at the 
clefts of the toes, they each send up between the metatarsal bones a 
branch called perforating (anterior), to open into the digital branches on 
the dorsum of the foot. 
11. Posterior Perforating 
The posterior perforating, three in number, pass up between the heads 
of the three outer interosseous muscles to anastomose with the metatarsea 
artery on the dorsum of the foot. 
The Anterior Tibial Artery 
The anterior tibial artery begins where the popliteal forks, at the lower 
border of the popliteus muscle, beneath the tendinous arch of the soleus, 
and passes directly forward between the tibia and fibula to the front of the 
leg which it descends, lying, for the upper two thirds of its course, on the 
interosseous membrane, and for the lower third on the front of the tibia, to 
terminate on the middle of the front of the ankle joint, beneath the an- 
nular ligament, by assuming the name of dorsalis pedis. 
Relations, 
The anterior tibial is divided into three portions, upper, middle and 
lower thirds. 
In its upper third it lies on the front of the interosseous membrane The Arteries. 
269 
between the tibialis anticus internally and the extensor longus digitorum 
externally. In its middle third it still lies on the interosseous membrane, 
but has reached the origin of the extensor proprius pollicis and this 
muscle lies on the outer side, while the tibialis anticus still remains 
internal. 
In its lower third it lies on the front of the tibia and is crossed obliquely 
by the tendon of the extensor proprius pollicis, which displaces the tibialis 
anticus and becomes the internal relation, while the extensor longus digi- 
torum again comes into relation with it externally. 
The artery is accompanied by satellite veins and the anterior tibial 
nerve. The nerve is at first to its outer side; then for a short distance in 
front of it and then again to the outer side. 
Branches. 
The branches of the anterior tibial artery are muscular, a recurrent 
branch, which ascends to the front of the knee through the tibialis anti- 
cus muscle, and two malleolar branches, external and internal, which sur- 
round the tibia just above the ankle-joint and supply that joint. 
The Dorsalis Pedis Artery. 
The dorsalis pedis artery is the continuation of the anterior tibial. It 
begins beneath the annular ligament, about the middle of the front of the 
ankle-joint, and passes forward along the inner side of the dorsum of the 
foot to terminate at the posterior extremity of the first interosseous space 
by dividing into the dorsalis hallucis and the communicating. 
Relations. 
It has the same relations to muscles and cords as the lower third of the 
anterior tibial. To its inner side is the extensor proprius pollicis ten- 
don, to its outer side the extensor longus digitorum and near its termi- 
nation it is crossed by the tendon of the extensor brevis digitorum to the 
great toe. It lies between satellite veins and has the anterior tibial nerve 
to its outer side. 
Branches. 
TARSEA. 
METATARSEA. 
DORSALIS HALLUCIS, 
COMMUNICATING. 
I. Tarsea. 
The tarsea branch passes outward on the tarsus 270 
Notes on Anatomy. 
11. Metatarsea. 
The metatarsea branch passes outward on the bases of the metatarsal 
bones and receives the posterior perforating- branches from the plantar 
arch. The metatarsea sends forward three branches called interosseous, 
which, after receiving the anterior perforating branches of the plantar 
digital arteries, divide at the clefts of the toes to form collateral digital 
branches for the dorsal aspect of the fifth, fourth and third toes and the 
outer side of the second toe. 
111. Dorsalis Hallucis 
The dorsalis hallucis is one of the two terminal branches of the dorsa- 
lis pedis and runs forward to supply dorsal collateral digital branches for 
the great toe and inner side of the second toe. 
IV. Communicating. 
The communicating passes through the first interosseous space to anas- 
tomose with the termination of the external plantar, giving off a branch, 
the magna pollicis, which passes forward and divides to form plantar col- 
lateral digital branches for the great toe and inner side of the second toe. 
The Internal Carotid Artery. 
The internal carotid artery is one of the two terminal branches of the 
common carotid and begins where that artery terminates on a level with 
the upper border of the thyroid cartilage and ascends on the front of the 
transverse processes of the three upper cervical vertebrae to the carotid 
aperture situated about the centre of the basilar face of the petrous por- 
tion of the temporal bone; it then runs forward and inward along the 
carotid canal in this bone and emerges at its apex to pass forward in the 
cavernous groove beside the sella turcica, and, lastly, turns upward be- 
side the anterior clinoid process and divides into its four terminal branch- 
es, viz: anterior cerebral, middle cerebral, posterior communicating and 
anterior choroid. 
Relations. 
Its relations to muscles and structures other than cords are as follows : 
Behind it are the anterior tubercles of the transverse processes of the 
three upper cervical vertebrse, separated from the artery by the origin of The Arteries. 
271 
the rectus capitis anticus major. In front of it, and separating it from 
the second and third portions of the external carotid artery are the paro- 
tid gland, the stylo-glossus and stylo-pharyngeus muscles and the stylo- 
hyoid ligament. To its inner side are the pharynx and tonsil gland. 
Its relations to cords are as follows: 
At its commencement it lies external to the external carotid artery, but 
by the time the external carotid has reached the stylo-hyoid and posterior 
belly of the digastric muscles the internal has passed behind it and is 
thence forward separated from it by the structures mentioned above and 
by the glosso-pharyngeal nerve. Behind the internal carotid, where it 
is entering the carotid foramen, are situated the jugular and anterior con- 
dyloid foramina and from these emerge the internal jugular vein, the 
pneumogastric and glosso-pharyngeal nerves, consequently these cords 
are here behind the artery, but they speedily get to its outer side as they 
descend. The internal jugular vein and pneumogastric nerve continue 
external to the artery throughout, but the glosso-pharyngeal and hypo- 
glossal nerves cross over the front of the artery: the hypoglossal near its 
commencement, the glosso-pharyngeal higher up. 
The internal carotid artery is divided into four portions. The first por- 
tion, which is also known as the cervical portion, extends from its origin 
to the carotid aperture. Its relations were given above. The second, 
or petrous, portion is that part of the artery which lies in the carotid 
canal of the petrous portion of the temporal bone; the third, or caver- 
nous, portion extends from the apex of the petrous bone along the sella 
turcica in the cavernous sinus to the anterior clinoid process, the fourth, 
or cerebral, portion ascends beside the anterior clinoid process. 
Branches 
The first portion gives off no branches. The second portion produces 
one unimportant branch, the tympanic, which passes to the tympanum. 
The third portion gives origin to three branches. Two of these, the 
arteria receptaculi, are unimportant and are distributed to the cavernous 
sinus and dura mater; the third is an important branch, the opthalmic 
artery. 
The Opthalmic Artery. 
The opthalmic artery springs from the internal carotid about the ter- 
mination of its third portion and passes forward into the orbit through 
the optic foramen, first lying below and external to the optic nerve, then 
crossing to the inner side of the nerve and running forward along the 272 
Notes on Anatomy. 
inner wall of the orbit to divide at the internal angle of the orbit into two 
branches, frontal and nasal. 
Branches. 
The branches of the opthalmic artery are ten in number. 
i. Lachrymal. 
The lachrymal artery runs forward along the outer wall of the orbit 
and after supplying the lachrymal gland passes on to the upper eye-lid. 
It gives off temporo-malar branches which pass through the bone to the 
temporal muscle. 
2. Supra-Orbital. 
The supra orbital runs forward on the levator palpebrae muscle and 
escaping to the forehead through the supra-orbital foramen, is there dis- 
tributed by a superficial and a deep branch. 
3 and 4. Anterior and Posterior Ethmoidal. 
The anterior and posterior ethmoidal arteries escape through the ante- 
rior and posterior ethmoidal foramina, and are distributed to the dura 
mater, ethmoidal cells and nasal fossae. 
5. Palpebral. 
The palpebral arteries, superior and inferior, arise from the opthalmic 
near its termination. The superior runs outward on the upper lid near 
its free edge, between the orbicularis palpebrarum and the tarsal cartilage 
and is there distributed; the inferior does the same for the lower lid. 
The two sometimes arise by a common trunk. 
6. Frontal. 
The frontal, one of the two terminal branches of the opthalmic artery, 
emerges at the inner angle of the orbit and ascends to be distributed 
along the middle of the forehead. 
7. Nasal. 
The nasal, the other terminal branch of the opthalmic artery, emerges 
at the inner angle of the orbit and is distributed along the bridge of the 
nose. The Arteries. 
8. Arteria Centralis Retinae. 
The arteria centralis retinae pierces the optic nerve and runs forward in 
it to reach the retina and be there distributed. 
g. Muscular. 
The opthalmic gives off numerous muscular branches in its course 
which are divided into two sets, superior and inferior, the superior spring- 
ing by one trunk and the inferior by another. 
io. Ciliary 
The ciliary arteries consist of three sets, viz: 
ist. Short ciliary branches, which are numerous small arteries which 
pierce the sclerotic around the optic nerve and supply the choroid. 
2d. Long ciliary, which are two branches piercing the sclerotic on 
opposite sides and running forward between it and the choroid to be dis- 
tributed to the iris. 
3d. Anterior ciliary branches, which are the offspring of muscular 
branches and pierce the sclerotic near the front of the eye to reach the 
iris. 
The branches from the fourth or cerebral portion are four. 
Anterior Cerebral Artery. 
The anterior cerebral artery, one of the terminal branches of the in- 
ternal carotid, runs forward in the longitudinal fissure, ascends the genu 
of the corpus callosum and runs backward along that body. 
Passing from the anterior cerebral of one side to that of the other, 
soon after their origin, is a communicating branch called the anterior 
communicating artery. 
Middle Cerebral Artery. 
The middle cerebral, arising as one of the terminal branches of the in- 
ternal carotid, passes outward along the fissure of Sylvius to be distributed 
to the anterior and middle lobes of the cerebrum and to the convolutions 
forming the island of Reil. 274 
Notes on Anatomy. 
Anterior Choroid Artery. 
The anterior choroid pierces the base of the brain to enter the descend- 
ing cornu of the lateral ventricle and form the choroid plexus. 
Posterior Communicating Artery. 
The posterior communicating artery, the last of the four terminal 
branches of the internal carotid, passes backward to anastomose with the 
posterior cerebral of the basilar artery. 
Circumscribing the six-sided space at the base of the brain is a series 
of arteries and their communications forming what is called the vascular 
circle of Willis. Beginning in front we have the anterior communicat- 
ing, and, following the arteries back on one side, they come in this or- 
der, anterior cerebral, internal carotid, posterior communicating, posteri- 
or cerebral and the termination of the basilar artery. Following them 
forward from the basilar artery they come in the reverse order. The Veins. 
275 
THE VEINS. 
The veins are the vessels which return the blood which the arteries 
have carried to the capillaries; consequently the course of the venous 
current is the opposite of the arterial, viz: towards the heart, into which 
they open after converging to form two trunks, superior and inferior ve- 
nae cavse. The veins, as a rule, accompany the arteries either singly or 
in pairs, as satellite veins, and the size of the vein, or veins, which return 
the blood, from a part is much greater than that of the arteries which car- 
ry the blood to the part. In the extremities there are two sets of veins, 
a superficial set which course just beneath the skin in the superficial fas- 
cia, and a deep set, the satellite veins; so that here the veins accompany- 
ing the arteries are remarkably small, especially in the upper extremity 
where the superficial are large and numerous. Ultimately, however, after a 
longer or shorter course, the two sets coalesce. The companion vein of 
an artery, as a rule, receives accessaries corresponding to the branches 
which are emitted by the artery, though to this there are some notable 
exceptions. 
The Veins of the Lower Extremity 
The veins of the lower extremity consist of two sets, superficial and 
deep or satellite. 
Beginning, then, with the satellite veins, we find that those of the pos- 
terior tibial artery have been formed, where that artery terminates, by the 
coalescence of the four satellite veins of the two plantar arteries, and as- 
cend receiving tributaries in correspondence with the branches of the 
artery until they reach the point where the popliteal artery terminates, 
and there unite with the satellite veins of the anterior tibial artery to form 
the popliteal vein. The satellite veins of the anterior tibial artery are the 
continuation of those of the dorsalis pedis, and, ascending and growing 
by accessaries corresponding to the branches of the artery, they termi- 
nate by coalescing with the satellite veins of the posterior tibial to form 
the popliteal vein. The popliteal vein thus formed lies at first to the 
inner side of the artery, but as it ascends it crosses superficially to the 
outer side and there remains until it terminates at the lower third of the 
thigh by becoming the femoral. The popliteal vein receives not only 276 
Notes on Anatomy. 
tributaries corresponding to the branches of the popliteal artery, but also 
one of the superficial veins called the short saphenous. The femoral 
vein, commencing where the popliteal ceases at the lower third of the 
thigh, ascends in company with its artery, lying at first to its outer side, 
then behind and finally internal to it and terminates by becoming the ex- 
ternal iliac vein at the point where the femoral artery commences. The 
femoral vein, as it advances, receives accessaries corresponding to the 
branches of its artery and also the second of the two superficial veins, the 
long saphenous, which opens into it just below Poupart’s ligament. 
Thus it is seen that from the commencement of the femoral to the termi- 
nation of the popliteal artery, the artery of the lower extremity is accom- 
panied by only one vein. 
The Superficial Veins of the Lower Extremity. 
The superficial veins of the lower extremity consist of two trunks 
called external or short and internal or long saphenous. 
Short Saphenous Vein. 
The short saphenous vein begins on the outer side of the dorsum of 
the foot, ascends behind the external malleolus and, with an inclination in- 
ward, gains the groove between the two heads of the gastrocnemius 
muscle and continues its course upward to open into the popliteal vein, 
having received numerous accessions in its course. 
Long Saphenous Vein. 
The long saphenous commences on the inner side of the dorsum of 
the foot and ascends in front of the internal malleolus, behind the inter- 
nal condyle of the femur; and then, after ascending the inner side of the 
thigh for some distance, inclines to the front and, just below Poupart’s 
ligament, pierces the fascia lata and opens into the femoral vein, gather- 
ing as it runs tribute from many smaller superficial veins and receiving, 
just as it is about to terminate, the veins from the first four branches of 
the artery. 
External Iliac Vein. 
The external iliac vein begins where the femoral terminates and passes 
upward and inward along the brim of the pelvis to unite with the inter- 
nal iliac vein on the disk between the fifth lumbar vertebra and the base 
of the sacrum to form the common iliac vein. It receives accessaries cor- The Veins. 
277 
responding to the two branches of the external iliac, epigastric and cir- 
cumflex iliac arteries. 
The two external iliac veins bear different relations to their arteries. 
The vein of the left side is internal and abreast of its artery, then inter- 
nal and on a plane posterior; while that of the right is first internal, 
then behind, then behind and external. 
Internal Iliac Vein 
The internal iliac vein is formed by the coalescence of the veins accom- 
panying the branches of the internal iliac artery. The veins of the vis- 
ceral branches are so numerous and intersecting that they form plexuses. 
The vein thus formed ascends behind its artery and unites with the ex- 
ternal iliac vein on the disk between the fifth lumbar vertebra and the sa- 
crum to produce the common iliac vein. 
The Common Iliac Vein. 
The common iliac vein results from the union of the external and inter- 
nal iliac veins on the disk between the fifth lumbar vertebra and the sa- 
crum, and passes upward and inward to unite with its fellow of the oppo- 
site side on the right side of the disk between the fourth and fifth lumbar 
vertebrae to form the inferior vena cava. The average length of the vein 
is two inches, but the vein of the left side is the longer. The relation of 
each vein to its artery is as follows: 
The left vein is behind and internal to its own artery and crosses be- 
hind the right artery. The right vein is behind and external to its artery. 
The Inferior Vena Cava. 
The inferior vena cava begins by the union of the two common iliac 
veins on the right side of the disk between the fifth and fourth lumbar 
vertebrae and ascending to the right of the abdominal aorta perforates the 
diaphragm and empties into the venous auricle. 
The inferior vena cava receives tributaries corresponding only to some 
of the branches of the aorta. Eventually it receives all of this blood; 
but the veins accompanying the arteries distributed to the organs of di- 
gestion coalesce into a trunk, the portal vein, which discharges itself into 
the capillaries of the liver, from which the blood is collected by the 
hepatic veins and by them discharged into the inferior vena cava at the 
posterior border of the liver. 278 
Notes on Anatomy. 
The Portal Vein. 
The portal vein is formed by the union of the superior mesenteric and 
splenic veins behind the head of the pancreas and ascends in the right 
border of the lesser omentum, between and behind the hepatic artery and 
duct, to the transverse fissure of the liver where it divides into a branch 
for each of the two lobes. It is about four inches long. Although the 
portal vein is formed directly by the union of the superior mesenteric and 
splenic veins, it also conveys the blood from the inferior mesenteric and 
gastric veins, for these two open into the splenic veins. As stated, the 
blood carried to the liver by the portal vein is collected by the hepatic 
veins, which emerge at three or four apertures on the posterior border 
of the liver and open into the inferior vena cava. 
The Spermatic Vein. 
The spermatic vein begins in the testicle by a plexus which ascends as 
numerous small veins along the cord to the internal abdominal ring, 
where, uniting into two veins, they pass upward and inward and soon 
unite to form a single trunk. The vein of the right side opens into the 
inferior vena cava, while that of the left empties into the left renal vein, 
having been crossed by the sigmoid flexure of the colon. 
The veins of the upper extremity are arranged in two sets, deep and 
superficial. 
The Veins of the Upper Extremity. 
The Deep Veins. 
The deep or satellite veins of the upper extremity are remarkably 
small, owing to the great amount of blood flowing through the super- 
ficial veins. 
The satellite veins of the radial and ulnar arteries, formed by the veins 
accompanying the branches of those two arteries, coalesce, a finger’s 
breadth below the middle of the front of the elbow-joint, to form the 
satellite veins of the brachial artery. The brachial satellite veins, having 
collected the blood from the veins accompanying the branches of the 
brachial artery, unite, where the axillary artery terminates, to form the 
axillary vein, which passes upward and inward, lying to the inner front 
aspect of the axillary artery to cease at the outer border of the first rib 
by becoming the subclavian vein, having received acccessions in corre- 
spondence with the branches of the axillary artery. The Veins. 
279 
The Superficial Veins. 
The superficial veins of the upper extremity are seven in number. 
Anterior Ulnar. 
The anterior ulnar vein begins on the inner side of the front of the 
forearm and ascends to unite with the posterior ulnar vein just below 
the elbow. 
Posterior Ulnar. 
The posterior ulnar vein passes up the inner side of the back of the 
forearm, turns forward and unites with the anterior ulnar, just below the 
elbow, to form the common ulnar. 
The Common Ulnar. 
The common ulnar vein ascends to the inner side of the front of the 
elbow to unite with the median basilic vein to form the basilic vein. 
Radial. 
The radial vein commences on the outer side of the back of the hand 
and ascends with an inclination forward and inward to terminate at the 
outer side of the front of the elbow by uniting with the median cephalic 
to form the cephalic veins. 
Median. 
The median vein ascends along the middle of the front of the forearm 
from the hand to a little below the front of the elbow where it divides 
into two veins, the median cephalic and median basilic. The median 
cephalic passes upward and outward to unite with the radial and form 
the cephalic vein. The median basilic passes upward and inward to join 
the common ulnar and form the basilic vein. 
Basilic. 
The basilic vein commences at the inner side of the front of the elbow 
by the union of the common ulnar and the median basilic veins, and as- 
cends the inner side of the arm, lying to the inner side of the brachial 
artery. It is first superficial to the artery, lying superficial to the invest- 
ing fascia, but pierces that fascia to reach the level of the artery, and 280 
Notes on Anatomy. 
terminates by uniting with the brachial satellite veins, where they coalesce 
to produce the axillary vein. 
Cephalic. 
The cephalic vein begins at the outer side of the front of the elbowr, 
being formed by the union of the median cephalic and radial veins, and 
ascends the arm skirting the outer edge of the biceps muscle, then lying 
in the interval between the deltoid and pectoralis major and terminates in 
the axillary near the termination of that vein. Near its termination the 
cephalic receives a communication from one of the veins of the neck, the 
external jugular. 
The Axillary Vein. 
The axillary vein is formed by the junction of the brachial satellite 
veins and the basilic, at the termination of the axillary artery. It passes 
upward, a continuous relation to the inner front aspect of the axillary 
artery, to terminate where that artery commences by becoming the sub- 
clavian vein. It increases in size as it ascends by receiving tributaries 
corresponding to the branches of the axillary artery; and, near its ter- 
mination, it receives the cephalic vein. 
The Subclavian Vein. 
The subclavian vein is the continuation of the axillary. 
It passes horizontally inward behind the clavicle to unite, behind the 
sterno-clavicular articulation, with the internal jugular vein and form the 
vena innominata, The subclavian vein is in relation with its artery at its 
termination, there lying to its inner side, and at the commencement of the 
artery where the vein is found lying below. Between these two points 
the vein is below the artery and separated from it by the scalenus anticus 
muscle. 
The Right Vena Innominata. 
The right vena innominata begins behind the right sterno clavicular 
articulation by the union of the right subclavian and internal jugular 
veins and descends nearly perpendicularly to unite with the left vena in- 
nominata to form the superior vena cava. It is about one and one-fourth 
inches long and lies external to the arteria innominata. The Veins. 
The Left Vena Innominata. 
The left vena innominata, or great transverse vein, is formed behind 
the left sterno-clavicular articulation by the union of the left subclavian 
and internal jugular veins. It passes almost horizontally to the right, 
lying upon the arch of the aorta and in front of the origin of the three 
arteries springing therefrom, and unites with the right vena innominata 
to form the superior vena cava. The vena innominata receives acces- 
sions corresponding to the branches of the subclavian artery, except the 
veins accompanying the supra-scapular and transversa colli arteries which 
open into a superficial vein of the neck, the external jugular, which in 
turn opens into the subclavian. 
Superior Vena Cava. 
The superior vena cava is formed at the lower border of the second 
costal cartilage of the right side by the confluence of the two venae 
innominatae and descends to the right of the ascending aorta for about 
three inches to open into the venous auricle of the heart. 
The Azygos Veins. 
The azygos veins, right and left, are a means of communication be 
tween the two venae cavae. 
Right Vena Azygos 
The right vena azygos begins in the right lumbar region by a commu- 
nication with one of the lumbar veins, or the. renal vein, or even the 
inferior vena cava itself, and ascends along the front of the vertebral 
column, through the aortic opening in the diaphragm, to the right of the 
descending aorta, until it reaches the third dorsal vertebra, where it arches 
forward over the right bronchus and opens into the superior vena cava. 
It receives the right intercostal veins as far up as it extends and also the 
left vena azygos. 
The Left Vena Azygos. 
The left vena azygos begins in the left lumbar region in the same way 
as the right does and ascends to pierce the left crus of the diaphragm and 
pass upward beside the vertebral column as high as the sixth dorsal ver- 
tebra, where it crosses behind the aorta and opens into the right vena 282 
Notes on Anatomy. 
azygos. It receives the left intercostal veins as high up as it extends. 
The intercostal veins of each side, which lie above the azygos veins, open 
into a vein called the superior intercostal, right or left, the right superior 
intercostal opening into the right subclavian, the left into the left vena 
innominata. 
Veins of the Head and Neck. 
The veins of the head and neck comprise three veins called jugular, 
external, internal and anterior, and their formative branches. 
The Internal Jugular Vein. 
The internal jugular vein begins at the foramen lacerum posterius by 
the convergence of the vessels from the interior of the cranium and de- 
scends the neck, lying first behind the internal carotid and then external 
to the common carotid artery to terminate behind the sterno-clavicular 
articulation by uniting with the subclavian vein to form the vena innomi- 
nata of its side. It receives nearly all the blood returned from the rami- 
fication of the external carotid artery, the veins conveying this blood 
being thus described; The temporal and internal maxillary veins, having- 
collected the blood from the distribution of their arteries, coalesce in the 
substance of the parotid gland to form a common trunk called the tem- 
poro-maxillary, which, after descending a short distance, divides into two 
branches, one mounting over the sterno-mastoid muscle to become the 
external jugular, while the other opens into the facial vein. The facial 
vein begins on the forehead under the name of the frontal vein; this de- 
scends near the centre of the forehead to the internal angle of the eye, 
where it is called the internal angular vein, and then passes downward 
with the artery, taking the name of facial vein. Soon after reaching the 
neck it is joined by a branch of the temporo-maxillary vein and then 
it opens into the internal jugular vein about on a level with the upper 
border of the thyroid cartilage. It sometimes receives the lingual and 
superior thyroid veins, though usually these open into the internal jugu- 
lar vein. 
The External Jugular Vein. 
The external jugular vein commences in the parotid gland as a branch 
of the temporo-maxillary vein, which is joined by the posterior auricular 
vein and sometimes by the occipital, and descends across the outer face 
of the sterno-cleido-mastoid muscle, thence along its posterior border, 
across the third portion of the subclavian artery to open into the subcla- The Veins, 
283 
vian vein. Just before terminating- it receives the supra-scapular and 
transversa colli veins and has a communication across the clavicle with 
the cephalic vein. 
The Anterior Jugular Vein. 
The anterior jugular vein descends the front of the neck beside the 
middle line and just above the sternum, turns outward beneath the sterno- 
cleido-mastoid muscle and opens into the subclavian vein. It is always 
small and sometimes inconspicuous. 
The Sinuses of the Dura Mater. 
The veins which return the blood from the brain consist of those upon 
the surface of the brain, called superficial cerebral, those of the interior 
of the brain and certain canals in the layers of the dura mater, which re- 
ceive the blood from the foregoing, called sinuses. 
The Superficial Cerebral Vein. 
The superficial cerebral veins, although they may be seen on the whole 
surface of the brain, are especially long and numerous on the upper as- 
pect. These veins open into the sinuses which are near them. 
Deep Cerebral Veins. 
The blood from the interior of the brain is collected by veins which 
ultimately coalesce into two (the venae Galeni) which emerge beneath the 
posterior lobes of the cerebrum, one on each side, and open into the 
straight sinus of the tentorium. 
The Sinuses of the Dura Mater. 
The sinuses of the dura mater are nine in number as follows: 
Superior Longitudinal Sinus. 
The superior longitudinal sinus is found running from before backward 
in the attached margin of the falx major. Beginning in front at the for- 
amen coecum it passes backward, grooving the vault of the cranium, to 
terminate at the anterior occipital protuberance by dividing into the two 
lateral sinuses. It receives the superior superficial veins, which open in- 
to it from behind forward. 284 
Notes on Anatomy. 
The Lateral Sinuses. 
The lateral sinuses begin at the anterior occipital protuberance and 
pass outward along the horizontal limbs of the occipital cross, then curve 
downward over the posterior inferior angle of the parietal bone, the mas- 
toid portion of the temporal bone and again on the occipital bone to ter- 
minate in the jugular vein of either side at the posterior lacerated fora- 
men. The position of these sinuses is indicated in the dried bone by a 
groove. 
The Occipital Sinuses. 
The occipital are a pair of small sinuses which commence around the 
foramen magnum and ascend in the attached margin of the falx minor to 
open, at the anterior occipital protuberance, into the commencement of 
the lateral sinuses. 
Inferior Longitudinal Sinus. 
The inferior longitudinal sinus is small and unimportant. It runs back- 
ward in the lower, free, concave margin of the falx major to terminate, 
when it reaches the tentorium in the straight sinus. 
The Straight Sinus. 
The straight sinus, triangular in shape, runs horizontally backward 
along the centre of the upper surface of the tentorium, between the layers 
of the falx major, to terminate at the anterior occipital protuberance. 
It is thus seen that four sinuses, superior longitudinal, straight and 
two occipital convey their blood to the anterior occipital protuberance, 
and that the blood is removed from this point by the lateral sinuses, 
hence the place is called the torcular Herophili. The sinuses above de- 
scribed are found at the upper and back part of the brain, but there are 
others situated at the base as follows: 
The Cavernous Sinus 
The cavernous sinus occupies the groove on either side of the sella 
turcica. It commences in front by receiving the opthalmic vein and 
passes backward to terminate at the apex of the petrous bone by dividing 
into two, superior and inferior petrosal. Passing through the cavernous 
sinus from behind forward are the internal carotid artery and several The Veins. 
3 
285 
nerves. The sinuses of the two sides are connected by transverse com- 
munications, one in front and one passing behind across the sella turcica 
thus forming an arrangement called the circular sinus or sinus of Winslow. 
The Superior Petrosal Sinus. 
The superior petrosal sinus passes outward and backward along the 
upper border of the petrous bone to open into the lateral sinus just where 
it curves downward. 
The Inferior Petrosal Sinus 
The inferior petrosal sinus passes backward and outward along the 
posterior border of the petrous bone to terminate with the lateral sinus 
at the foramen lacerum posterius to form the internal jugular vein. 
The Transverse Sinus. 
The transverse sinus consists of one or more channels of communica- 
tion, across the basilar process of the occipital bone, between the two 
inferior petrosal sinuses. 
The Veins of the Diploe. 
Ramifying between the tables of the bones of the skull are numerous 
veins called diploetic. They take the name of the region they occupy 
and finally converge to four trunks which open either into the sinuses of 
the interior or the veins of the exterior. Connecting the sinuses of the 
interior with the veins of the exterior of the head are several veins which 
pass through foramina such as the mastoid and parietal. 
The Spinal Veins. 
The spinal veins consist of three sets, as follows: 
Dorsal Spinal Veins. 
The dorsal spinal veins are numerous veins forming a net-work on the 
exterior of the vertebrae. 
Meningo-Rachidian Veins. 
The meningo-rachidian are four veins perpendicular in direction, which 286 
Notes on Anatomy. 
lie within the spinal canal between the bone and dura mater, two in front 
and two behind. 
Medulli-Spinal Veins. 
The medulli-spinal are numerous veins ramifying beneath the arach 
noid membrane of the spinal cord. 
The Cardiac Veins. 
The veins of the heart are two, as follows: 
The Great Cardiac Vein. 
The great cardiac vein ascends in the anterior ventricular groove, 
winds around the left auriculo-ventricular groove and opens into the 
right auricle. The last inch of its course is known as the coronary sinus. 
The Posterior Cardiac Vein, 
The posterior cardiac vein is small and ascends in the posterior ven- 
tricular groove to open into the great cardiac vein. The Lymphatic System. 
287 
THE LYMPHATIC SYSTEM. 
The lymphatic system consists of numerous small vessels ramifying in 
nearly every tissue of the body, and of small, reddish, pea-like bodies 
called lymphatic glands, found at intervals along the lymphatic vessels. 
The lymphatic vessels are intended for the most part to remove from the 
tissues the detritus of assimilation, consisting mainly of unexpended 
plasma; consequently the course of their circulation is from the circum- 
ference towards the centre, and in their route they will be found to accom- 
pany the veins. 
Wherever they are found the lymphatics consist of two sets, super- 
ficial and deep. In the extremities the superficial set is found just 
beneath the skin; the deep in and among the muscles. In the viscera 
the superficial set ramifies on the surface, while the deep is found in the 
structure. The greater portion of the lymphatics of the body converge 
to form one large vessel, the thoracic duct, which empties into the venous 
current near the heart. 
The Thoracic Duct. 
The thoracic duct begins on the front of the body of the second lum- 
bar vertebra by a considerable dilatation called receptaculum chyli, 
which, narrowing to a tube the size of a goose quill, ascends the front of 
the vertebral column behind the descending aorta, passes through the 
aortic opening of the diaphragm and continues upward as high as the 
fourth dorsal vertebra, where it inclines to the left and continues thence 
an oblique ascent behind the arch of the aorta to a point on a 
level with the seventh cervical vertebra, where it arches forward 
and downward and opens into the commencement of the left vena 
innominata. Opening into the commencement of the right vena innomi- 
nata is another and much smaller lymphatic duct (ductus lymphaticus 
dexter) which conveys lymph furnished it by the right upper extremity 
and right side of the head and neck. 288 
Notes on Anatomy. 
Lymphatics of the Lower Extremity. 
The superficial lymphatics of the lower extremity are found crowding 
upward in immense numbers along the course of the saphenous veins 
and, reaching the saphenous opening in the fascia lata, where the vein 
terminates near Poupart’s ligament, they then pass through a set of lym- 
phatic glands. The deep lymphatic vessels accompany the deep veins 
upward to the groin, where they are connected with a set of glands, 
lying beneath the fascia lata and superficial muscles, called the deep lym- 
phatic glands of the groin. Along the course of these vessels are found 
a few glands, some in the popliteal space and one on the front of the 
interosseous membrane of the leg. The lymphatic vessels from the ex- 
ternal organs of generation and from the abdominal parietes can be traced 
to a third set of glands, which form a chain along Poupart’s ligament, 
lying superficial and above the glands around the saphenous opening. 
All these vessels pass beneath Poupart’s ligament to become the ex- 
ternal iliac lymphatics which accompany the external iliac vessels and 
unite with the internal iliac lymphatics to form the common iliac lympha- 
tics, which accompany the common iliac vessels and unite with those of 
the opposite side to form the lumbar lymphatics. Scattered at intervals 
along these vessels from Poupart’s ligament are lymphatic glands. The 
lumbar lymphatics ascend along the aorta, constantly increasing in size 
by accessions from the abdominal viscera, and having passed through 
numerous glands, and lessened in number as they increased in size, they 
eventually open into the receptaculum chyli, which is so named from the 
fact that the lymphatics which it receives from the small intestine are, 
during the process of digestion, filled with chyle. 
The Lymphatics of the Upper Extremity. 
The lymphatics of the upper extremity, like those of the lower, consist 
of a superficial and a deep set. The superficial ascend in company with 
the superficial veins and the deep accompany the deep veins, both con- 
verging to the arm pit where there are some twelve or fifteen lymphatic 
glands. Besides the vessels from the upper extremity these glands also 
receive those from the chest wall and mammary gland. A few glands are 
found along the course of the lymphatics before they reach the axilla, 
some at the elbow and some along the brachial vessels; these, however, 
are small and unimportant. From the axillary glands the vessels proceed 
along the course of the subclavian vein, opening on the left side into the The Lymphatic System. 
289 
termination of the thoracic duct and on the right into the ductus lym- 
phaticus dexter. 
Lymphatics of the Head and Neck 
The lymphatics of the head and neck consist of vessels which have 
come from the exterior of the head and others which have converged from 
veins supplying the internal and external jugular veins, no lymphatics, 
however, being found in the substance of the brain. 
These vessels descend along the external, and especially the internal, 
jugular veins and on the right side open into the ductus lymphaticus 
dexter while on the left they join the thoracic duct. 
The Lymphatics of the Thorax. 
The lymphatics accompanying the intercostal vessels open into the 
thoracic duct. Those from the right lung, some portion of the thoracic 
parietes, diaphragm and even some portion of the upper surface of the 
liver and the short border of the heart seek the ductus lymphaticus dex- 
ter; while those from the left lung, left side of the thorax and most of 
the heart join the thoracic duct. The vessels from the lungs pass through 
a set of glands situated around the bifurcation of the trachea called the 
bronchial glands. The Nervous System. 
291 
THE NERVOUS SYSTEM. 
The Cranial Nerves. 
The cranial nerves comprise twelve pairs, one on each side, those of 
one side having their counterpart on the other. 
The definition of a cranial nerve is that it appears at the base of the 
brain and emerges through an aperture in the skull. The point on the 
base of the brain where the nerve appears is called its apparent origin, 
since it may be traced into the interior of the brain to what is called its 
real origin. The real origin of many of the nerves is still a matter of 
dispute. 
The cranial nerves are named numerically in pairs from before back- 
ward; besides which each pair is known by another or several other 
names derived from the part to which the nerve is distributed. The fol- 
lowing table gives the synonymes of the twelve pairs: 
First Pair, Olfactory. 
Second Pair, Optic. 
Third Pair, Motores Oculorum. 
Fourth Pair, Pathetic (Trochleares). 
Fifth Pair, Trifacial (Trigeminus). 
Sixth Pair, Abducentes. 
Seventh Pair, Facial, Portio Dura. 
Eighth Pair, Auditory, Portio Mollis. 
Ninth Pair, Glosso-Pharyngeal. 
Tenth Pair, Pneumogastric, Par Vagum, Vagus. 
Eleventh Pair, Spinal Accessory. 
Twelfth Pair, Hypoglossal (Lingual). 
These twelve pairs were formerly considered as only nine from the fact 
that, as will be seen, they emerge through nine foramina in the cranium. 
The classification into nine pairs is known as that of Willis and the one 
just given as that of Sommering. The two classifications are similar for 
the first six pairs, the seventh pair in Willis’ classification consisted of the 292 
Notes on Anatomy. 
seventh and eighth, while the eighth consisted of the glosso-pharyngeal, 
pneumogastric and spinal accessory and the ninth of the hypoglossal. 
A general outline of the cranial nerves successively, from their appa- 
rent origin to their point of emergence, will first be given and afterwards 
each pair will be taken up and described. 
The first seen on the base of the brain from before backward is the 
first pair. The first nerves lie on the under surface of the anterior lobe 
of the cerebrum in a groove a little external to the longitudinal fissure, 
having its commencement by a three forked origin just in front of the 
anterior perforated space. Near the anterior extremity of the anterior 
cerebral lobe it enlarges into an oval-shaped mass which lies upon the 
cribriform plate of the ethmoid bone and sends its branches of distribu- 
tion through the foramina seen there. 
The second nerve is first seen under the name of the optic tract, ap- 
proaching its fellow from the outer aspect of the crus cerebri and passing 
beside the tuber cinereum and uniting in front of it with its fellow to form 
the optic chiasm or commissure from which the two optic nerves diverge 
forward to enter the orbit through the optic foramina. 
The third nerve is seen emerging to the inner side of the crus cerebri, 
just in front of the pons Varolii, and runs forward to leave the cranium 
through the anterior foramen lacerum. 
The fourth nerve has its apparent origin external to the third, on the 
optic side of the crus cerebri, and also has its exit through the anterior 
foramen lacerum. 
The fifth is the largest of the cranial nerves and is first seen just be- 
hind the origin of the fourth. It pierces the lateral aspect of the pons 
Varolii and splits into three portions, opthalmic, superior and inferior 
maxillary, which require three apertures of exit from the cranium. 
The opthalmic leaves through the anterior foramen lacerum, the supe- 
pior maxillary through the foramen rotundum, the inferior maxillary 
through the foramen ovale. 
The sixth nerve takes its apparent origin behind that of the fifth from 
the upper constricted portion of the medulla oblongata, just behind the 
pons Varolii, and passes forward to gain egress through the anterior fora- 
men lacerum, which is thus seen to transmit three entire cranial nerves, 
viz; third, fourth and sixth, and a part of another, viz: the opthalmic 
branch of the fifth. 
The seventh, eighth, ninth, tenth and eleventh all arise in the order 
named, from above downward, in the groove between the corpora olivare 
and restiformia of the medulla oblongata. The seventh and eighth leave The Nervous System. 
293 
the cranium through the same opening, the internal auditory meatus, 
while the ninth, tenth and eleventh all gain exit through the posterior 
foramen lacerum. 
The twelfth has its apparent origin to the inner side of the five pre- 
ceding nerves, from the groove between the corpora olivare and pyrami- 
dale, by numerous filaments which are speedily collected into two cords, 
which unite to form the nerve as it emerges through the anterior condy- 
loid foramen. 
The First Nerve. 
The first or olfactory nerve arises by a three forked origin close to the 
anterior perforated space. The external or long root consists of white 
fibres and may be traced along the fissure of Sylvius into the middle lobe 
of the cerebrum; the middle root is of gray matter and springs from the 
posterior part of the anterior lobe; the inner or short root is of white 
fibres and also arises from the posterior part of the anterior lobe. The 
three roots unite to form the nerve, just in front of the anterior perforated 
space, which passes forward, triangular in shape and grayish in color, 
lying in a groove on the under surface of the anterior lobe of the cere- 
brum a little external to the longitudinal fissure. The nerve swells into 
an oblong grayish enlargement, called the bulbus olfactorius, which lies 
beside the crista galli on the cribriform plate of the ethmoid bone. From 
the under surface of the olfactory bulb are given off some twenty fila- 
ments, which descend into the nose through the foramina of the cribriform 
plate to be distributed to the mucous membrane of the nose as far down 
as the middle turbinated bone. These filaments may be arranged in 
three sets, viz: those to the septum, those to the external wall and those 
to the roof of the nose. 
Second Nerve 
The second or optic nerve has its apparent origin just external to the 
crus cerebri, whence it may be traced to its deep or real origin from 
various parts of the optic thalamus and from the corpora quadrigemina. 
Winding around the outer side of the crus cerebri, it passes forward and 
inward beside the tuber cinereum and in front of it unites with its fellow 
to form the optic commissure or chiasm. The portion extending from 
the origin to the optic chiasm is called the optic tract. From the optic 
chiasm the two optic nerves diverge anteriorly to enter the orbit through 
the optic foramina, each piercing the sclerotic and choroid coats of the 
eye-ball to expand into the retina. 294 
Notes on Anatomy, 
The connection between the optic tract, chiasm and nerve is as fol- 
lows: The optic tract is composed of filaments, the outermost of which 
pass into the nerve of that side, while the innermost curve over, through 
the chiasm, to form the innermost fibres of the opposite tract, and the 
middle fibres of the tract of one side pass through the chiasm to form 
the middle fibres of the nerve of the opposite side; and the innermost 
fibres of one nerve pass through the chiasm and become the innermost 
fibres of the opposite nerve, thus accounting for all the filaments. 
Third Nerve. 
The third nerve, or motor oculi, leaves the brain to the inner side of 
the crus cerebri close to the front of the pons Varolii, passes forward in 
the outer wall of the cavernous sinus, enters the orbit through the fora- 
men lacerum anterius and divides into two branches, which supply all the 
muscles of the orbit except the superior oblique and external rectus. As 
it enters the orbit it lies between the two heads of the external rectus 
muscle and thence one of its branches ascends to supply the superior 
rectus and levator palpebrse, while the other is distributed to the internal 
and inferior recti and the inferior oblique. All its fibres enter the muscles 
on their ocular aspects. 
Fourth Nerve 
The fourth nerve, or patheticus, appears external to the apparent origin 
of the third, viz: to the outer side of the crus cerebri, and passing for- 
ward in the outer wall of the cavernous sinus, enters the orbit through 
the foramen lacerum anterius and is distributed to the superior oblique 
from its orbital surface. 
Fifth Nerve 
The fifth nerve, or trifacial, or trigeminal, appears just behind the 
fourth emerging from the lateral aspect of the pons Varolii. It arises by 
two roots which are known as the anterior, small or motor root and the 
posterior, large or sensitive root. The large root passes forward over 
the superior border of the petrous bone near its apex, and then swells 
into a ganglion known as that of Gasser, which lies in the digital depres- 
sion seen on the anterior face of the petrous bone. The small root 
passes forward beneath the large and is found lying under the ganglion 
of Gasser without participating in its formation. The Nervous System. 
295 
The ganglion divides into three branches, opthalmic, superior maxillary 
and inferior maxillary. The latter is joined bodily by the small root of 
the nerve and is, therefore, the only one of the three divisions possessing 
motor endowments. 
I. The Opthalmic Nerve. 
The opthalmic branch passes forward and soon divides into three 
branches, lachrymal, frontal and nasal, which enter the orbit through the 
foramen lacerum anterius. 
i. Lachrymal Nerve. 
The lachrymal nerve passes forward along the outer wall of the orbit 
to supply the lachrymal gland, and, not being exhausted in this duty, 
continues its course to emerge at the outer angle of the orbit and supply 
the adjacent integument. 
2. Frontal Nerve. 
The frontal branch passes forward on the levator palpebrse muscle and 
divides into two branches, supra-orbital and supra-trochlear. 
ist. The supra-orbital branch emerges from the orbit at the supra- 
orbital foramen to supply the upper lid and muscles and integument of 
the forehead as far back as the vertex of the skull. 
2d. The supra-trochlear branch advances to the inner angle of the 
orbit where it emerges above the fovea trochlearis, hence its name, and is 
distributed to the inner angle of the eye and the integument of the root 
of the nose and middle of the forehead. 
3. Nasal Nerve. 
The nasal branch crosses the optic nerve, advances along the inner 
wall of the orbit, re-enters the cranium through the anterior ethmoidal 
foramen and is there found lying in the slit beside the crista galli, whence 
it sinks into the cavity of the nose and divides into a branch for the 
mucous membrane of the nose, and another to descend along the poste- 
rior aspect of the nasal bone to its lower edge, where it emerges through 
the notch found there and supplies the integument of the nose to its tip. 
Just as the nasal nerve is entering the ethmoidal foramen it gives off a 
branch called the infra-trochlear, which passes forward to emerge at the 
inner angle of the orbit below the fovea trochlearis and supply the lach- 296 
Notes on Anatomy. 
rymal sac and inner angle of the eye. Besides the infra-trochlear it 
gives off in the orbit three other branches; one to the opthalmic ganglion 
of the sympathetic system and two ciliary branches which pierce the 
sclerotic coat, pass forward between it and the choroid and are distribu- 
ted to the iris. 
11. Superior Maxillary Nerve. 
The superior maxillary branch of the fifth nerve, like the opthalmic, 
has a forward course. It gains egress through the foramen rotundum, 
continues its forward direction across the spheno-maxillary fossa, along 
a groove on the floor of the orbit, sinks beneath the floor and emerges 
at the infra-orbital foramen on the face to give sensibility to adjacent 
parts, viz: the lower lid, cheek, side of the nose and upper lip. 
Branches 
Besides the terminal ones, the branches of the superior maxillary are 
the following, emitted in the order given: 
i. Orbital 
The orbital, or temporo-malar, branch enters the orbit through the 
spheno-maxillary fissure and divides into two branches, temporal and 
malar. The temporal branch enters the temporal fossa through the outer 
wall of the orbit, while the malar branch continues along the outer wall 
of the orbit to emerge on the cheek at the outer angle. 
2. Spheno-Palatine. 
The spheno-palatine are two branches of communication which de- 
scend to Meckel’s ganglion of the sympathetic in the spheno-maxillary 
fossa. 
3. Dental Branches. 
The chief distribution of the superior maxillary is to the teeth and 
gums of the upper jaw and this is effected by two branches, anterior and 
posterior dental. The posterior dental is first emitted and supplies the 
molar and bicuspid teeth. The anterior dental leaves the main trunk 
just as it is about to emerge on the face and supplies the two incisors, 
the canine and the front bicuspid. The anterior and posterior dental 
nerves anastomose in the bone and supply each tooth with as many fila- 
ments as the tooth has fangs, besides giving twigs to the gums. The Nervous System. 
297 
111. Inferior Maxillary Nerve. 
The inferior maxillary branch of the fifth nerve consists of a branch from 
the ganglion of Gasser and the small motor root of the fifth nerve, which 
unite and pass downward through the foramen ovale, immediately after 
emerging from which the nerve divides into an anterior and a posterior 
trunk. The distribution of each trunk is as follows: 
i. The anterior trunk breaks up into branches which supply the mus- 
cles of mastication, each branch bearing the name of the muscle to which 
it is distributed and conveying motor influence. 
2. The posterior trunk divides into three branches, inferior dental, 
gustatory and auriculo-temporal. 
ist. Inferior Dental. 
The inferior dental branch curves forward and downward to enter the 
dental foramen of the lower jaw and run along a canal in the bone giving 
filaments to all the teeth of the lower jaw. As it passes the mental fora- 
men it gives off a branch which escapes through that foramen and sup- 
plies the integument of the lower lip. Just before entering the dental 
foramen the nerve gives off a branch called the mylo-hyoidean, which 
descends along the groove on the inner surface of the inferior maxilla and 
is distributed to the mylo-hyoid muscle and the anterior belly of the 
digastric. 
2d. Gustatory Branch. 
The gustatory nerve passes downward and forward, first behind the 
external pterygoid muscle, then between the pterygoid muscles and then 
between the internal pterygoid and ramus of the lower jaw, and reaching 
the side of the tongue splits into many filaments to supply the anterior 
part of that organ. While between the two pterygoid muscles it receives 
at an acute angle the chorda tympani nerve, a branch of the seventh 
nerve, which it transmits to the submaxillary ganglion of the sympathetic. 
Beneath the tongue the gustatory gives off a branch of communication 
to the twelfth. 
3d. Auriculo-Temporal. 
The auriculo-temporal branch arises by two roots. It first passes 
backward behind the articulation of the lower jaw, then ascends between 
the meatus auditorius externus and condyle of the lower jaw and emerging 
from beneath the parotid gland divides into branches called anterior and 298 
Notes on Anatomy. 
posterior temporal which supply the integument of the temporal region. 
It gives off branches to the articulation of the lower jaw, to the parotid 
gland, to the pinna, to the meatus auditorius and two communicating 
branches to the facial nerve. 
Sixth Nerve. 
Gray Mass—Floor of the Fourth Ventricle 
The sixth nerve, or abducens, has its apparent origin from the upper 
constricted portion of the medulla just behind the pons Varolii and ad- 
vances along the inner wall of the cavernous sinus to enter the orbit 
through the anterior foramen lacerum and be distributed, often passing 
between its two heads, to the ocular face of the external rectus muscle. 
Seventh Nerve. 
The seventh, or facial, nerve (the motor nerve of the face) is the up- 
permost of the five nerves which spring from the groove between the 
corpora olivare and restiformia. Just beneath it, in the same groove, is 
another nerve called the portio intermedia which unites with it. If this 
be counted as a separate nerve, it may be said that there are six nerves 
springing successively from this groove. It makes for the internal audi- 
tory meatus which it enters in company with the auditory nerve; and 
when the two reach the bottom of the canal the facial parts from its com- 
panion and enters another canal in the petrous bone called the aqueduct 
of Fallopius, which conducts it first outward, then backward and then 
downward to the stylo-mastoid foramen, emerging from which it passes 
forward through the parotid gland, over the external carotid artery, and 
divides into numerous branches which are distributed to all the muscles 
of the face except those of mastication, and of these the buccinator gets 
a branch. 
Branches. 
Besides its terminal filaments on the face; the facial gives off the fol 
lowing branches: 
ist. Auditory, which is furnished the auditory nerve while the facial 
is in the internal auditory meatus. 
2d. Tympanic, which arises from the facial while it is in the aqueduct 
of Fallopius and is distributed to a muscle of the tympanic cavity. 
3d. Chorda tympani, which is emitted from the facial just above the The Nervous System. 
299 
stylo-mastoid foramen and first ascends through the petrous bone and 
enters the tympanium at the base of the pyramid on its posterior wall, 
then crosses on the inner surface of the membrana tympani and leaves 
through the fissure of Glaser, having emerged from which it joins the 
gustatory branch between the two pterygoid muscles and continues with 
it to the submaxillary ganglion. 
After emerging from the stylo-mastoid foramen, the facial gives off the 
following branches: 
sth. Digastric, which is distributed to the posterior belly of the digas- 
tric muscle. 
4th. Stylo-hyoid, which supplies the stylo-hyoid muscle. 
6th. Posterior auricular, which ascends behind the ear and after com- 
municating with the auricular branch of the pneumogastric is distributed 
by an anterior branch to the auricle and by a posterior to the back of the 
head. 
Besides the foregoing the facial has numerous communicating branches. 
Three of these proceed from a gangliform swelling of the nerve called 
the intumescentia gangliformis, situated at the hiatus Fallopii. They are 
the nervus petrosus superficialis major to Meckel’s ganglion and the ner- 
vus petrosus superficialis minor to the otic ganglion and the external 
petrosal to the carotid plexus. 
After emerging the facial nerve communicates with the glosso-pha- 
ryngeal, and the auricularis magnus from the cervical plexus and receives 
two large branches from the auriculo-temporal. 
Eighth Nerve. 
Floor of the Fourth Ventricle. 
The eighth nerve, or portio mollis, or auditory, is the second of the 
nerves arising from the groove between the corpora olivare and resti- 
forme. It passes forward and enters, along with the seventh, the internal 
auditory meatus, at the bottom of which it divides into a cochlear and 
three vestibular branches, which are distributed to corresponding parts 
of the labyrinth. 
Ninth Nerve. 
Floor of the Fourth Ventricle. 
The ninth nerve, or glosso-pharyngeal, is the third nerve arising in the 
groove between the corpora olivare and restiforme. It escapes from the 
cranium, along with the tenth and eleventh, through the posterior fora- 300 
Notes on Anatomy. 
men lacerum, lying behind the internal carotid artery; it then passes for- 
ward between the artery and the internal jugular vein to the outer side 
of the artery, then crosses the artery in front of the posterior border of 
the stylo-pharyngeus, and then crosses that muscle to be distributed by 
its terminal filaments to the mucous membrane of the posterior part of 
the tongue. 
Branches. 
Besides its terminal branches the ninth nerve gives off four branches 
of distribution. While in the jugular foramen the nerve presents two 
gangliform enlargements. The uppermost of these, small and unimpor- 
tant, is called the jugular ganglion; while the lower is large and is called 
the petrous ganglion. From the latter there is one branch of distribution 
given off to the tympanum. 
ist. The tympanic branch passes to the tympanum through a canal 
which opens on the ridge of bone between the carotid and jugular fora- 
mina. After reaching the tympanum it is distributed by six branches, as 
follows: 
(a) One to the lining membrane of the tympanum and Eustachian 
tube. 
(b) One to the fenestra rotunda. 
(V) One to the fenestra ovalis. 
(d) One to the carotid plexus of the sympathetic. 
(<?) One to the great superficial petrosal nerve. 
(_/) One to the lesser superficial petrosal nerve. 
2d. A muscular branch which supplies the stylo-pharyngeus, posterior 
belly of the digastric and the stylo-hyoid. 
3d. The pharyngeal branches, which are found on the posterior part 
of the pharynx aiding to form a plexus called the pharyngeal from which 
the pharynx is supplied. The other nerves entering into the formation 
of this plexus are the pharyngeal and superior laryngeal of the tenth and 
the sympathetic. 
4th. The tonsillar branches which form a plexus on the tonsils. 
The branches of communication of the ninth nerve are as follows: 
ist. One to the ganglion of the tenth nerve. 
2d. One to the superior cervical ganglion of the sympathetic. 
3d. One to the seventh nerve. 
4th. Carotid filaments which descend with the carotid artery. The Nervous System. 
301 
Tenth Nerve, 
Floor of the Fourth Ventricle. 
The tenth nerve, or pneumogastric, or par vagum, is the fourth nerve 
arising from the groove between the corpora olivare and restiforme. It 
escapes from the cranium through the jugular foramen and descends the 
neck, enters the thorax through which it passes along with the oesopha- 
gus and gains the abdomen where it is found running from left to right 
along the lesser curvature of the stomach. In the neck the course and 
relations of the nerve are the same on both sides, i. <?., the nerve lies first 
between the internal jugular vein and the internal carotid artery, then 
between the internal jugular vein and common carotid artery until it 
reaches the root of the neck and the relations thenceforward vary accord- 
ing to the side. The right nerve at the root of the neck crosses the first 
portion of the subclavian artery, enters the chest, reaches the posterior 
aspect of the root of the right lung; descends thence along the posterior 
aspect of the oesophagus to the stomach and runs along the lesser curva- 
ture of that organ, being distributed by its terminal filaments to its pos- 
terior face. The left enters the thorax lying on the front of the first por- 
tion of the left subclavian, crosses the front of the arch of the aorta, 
reaches the posterior aspect of the root of the left lung and thence passes 
down the front of the oesophagus to the stomach, runs along its lesser 
curvature and is distributed to its anterior face. While in the jugular 
foramen the nerve presents a gangliform enlargement called the ganglion 
of the root, and about half an inch below this a second and larger one 
called the ganglion of the trunk. 
Branches. 
Besides the terminal or gastric branches, its branches of distribution 
are as follows: 
i. Pharyngeal, 
The pharyngeal branch arises from the ganglion of the root and de- 
scends to the posterior aspect of the pharynx to aid in forming the pha- 
ryngeal plexus. 
2. Superior Laryngeal 
The superior laryngeal branch arises from the ganglion of the trunk 
and descending pierces the thyro-hyoid membrane and is distributed to 302 
Notes on Anatomy. 
the mucous membrane of the larynx, giving a filament to the arytenoid 
muscle. Just below the thyro-hyoid membrane it gives off a branch, 
called the external laryngeal, which is distributed to the thyroid gland 
and crico-thyroid muscle and furnishes some filaments to the pharyngeal 
plexus. 
3. Recurrent Laryngeal. 
The recurrent or inferior laryngeal branch arises at a different point on 
each side; on the left it arises as the pneumogastric is crossing the aorta 
and winds backward around the aorta; on the right it arises as the nerve 
is crossing the first portion of the subclavian and winds around that 
artery. After its origin each nerve ascends in the groove between the 
trachea and oesophagus, giving filaments to those parts, and is distribu- 
ted to all the muscles of the larynx except the crico-thyroid. 
4. Posterior Pulmonary. 
The posterior pulmonary branches form an intricate plexus on the back 
of the root of the lung, whence filaments are sent along the bronchial 
tubes into the lungs. 
5. Anterior Pulmonary 
The anterior pulmonary branches form a smaller plexus on the front 
of the root of the lung. 
6. CEsophageal. 
The oesophageal branches are filaments furnished the oesophagus before 
the nerves are in relation with it. 
The two nerves communicate frequently around the tube, surrounding 
it with numerous anastomoses, thus forming the oesophageal plexus. 
7. Cardiac. 
The cardiac branches are numerous. They arise in the upper part of 
the neck, the lower part of the neck, the thorax and from the recurrent 
laryngeal nerve and are destined for the heart. 
The communications of the pneumogastric are as follows: The gang- 
lion of the root communicates with the ninth and eleventh nerves and 
with the superior cervical ganglion of the sympathetic, besides which it 
gives off an unimportant branch called the auricular which joins the facial The Nervous System. 
303 
nerve in the aqueductus Fallopii. The ganglion of the trunk communi- 
cates with the twelfth nerve and with the loop between the first and 
second cervical nerves. 
Eleventh Nerve. 
The eleventh nerve, or spinal accessory, is the fifth nerve arising in the 
groove between the corpora olivare and restiforme and escapes from the 
cranium through the posterior foramen lacerum along with the ninth and 
tenth nerves. The nerve consists of two portions: ist, a cranial or ac- 
cessary portion which arises from the groove mentioned and, after com- 
municating with the cervical portion, goes to the pneumogastric; 2d, a 
spinal portion which arises by successive filaments from the side of the 
spinal cord as low as the sixth cervical nerve and ascends between the 
two roots of the spinal nerves. It enters the cranium through the fora- 
men magnum and after communicating with the accessory portion 
emerges through the jugular foramen, passes downward and outward, 
pierces the sterno-cleido-mastoid muscle and reaches the trapezius to 
which it is distributed, giving, on its way, filaments to the sterno-cleido- 
mastoid. The two portions of this nerve are never closely united, but 
after the spinal portion has ascended to the cranium several communica- 
ting branches pass between them. 
Twelfth Nerve 
The twelfth nerve, or hypoglossal, arises from the groove between the 
corpora olivare and pyramidale by ten or twelve filaments which are 
gathered into two bundles: these pass outward and, just as they are 
leaving the cranium through the anterior condyloid foramen, unite to 
form the trunk of the nerve. The nerve then descends between the in- 
ternal jugular vein and internal carotid artery and, when it reaches a 
point on a level with the jaw, curves forward in front of both internal and 
external carotid arteries, and after communicating with the gustatory 
nerve is distributed to the muscles of the tongue. 
Branches. 
The branches of distribution, besides the terminal, are two, the de- 
scendens noni, a very important branch, and the thyro-hyoidean of small 
importance. 
ist. Descendens Noni Nerve. 
The descendens noni leaves the hypoglossal just as it is crossing the 304 
Notes on Anatomy. 
external carotid artery and derives its name from its direction and from 
the fact that the twelfth nerve was, in Willis’ classification, called the 
ninth. It passes down the neck on the front of the sheath of the ex- 
ternal, carotid artery, and then on the sheath of the common carotid, 
occasionally descending in the sheath. About the middle of the neck it 
anastomoses with filaments from the second and third cervical nerves, the 
communicans noni, forming what is called the arch of Scarpa, which lies 
in front of the sheath of the common carotid artery about the middle of 
the neck. From this arch branches are given to the depressor muscles 
of the hyoid bone, except the thyro hyoid. 
2. Thyro-Hyoidean. 
The thyro-hyoidean branch descends from near the termination of the 
hypoglossal nerve to supply the thyro-hyoid muscle. 
The Spinal Cord. 
The spinal cord, or marrow, or medulla spinalis, is that portion of the 
cerebro-spinal axis which is found in the spinal canal. In the adult it 
does not extend the whole length of the canal, but, beginning at the fora- 
men magnum, terminates in a pointed extremity at the lower border of 
the body of the first lumbar vertebra, from which point the canal is 
occupied by nerves to which the cord has given birth. In the young 
subject the cord reaches the whole length of the canal, but as development 
advances the canal increases in length much faster than the cord. 
The spinal marrow, like the brain, is enveloped by three membranes, 
dura mater, arachnoid and pia mater, which are continuous with similar 
membranes of the brain. The dura mater of the cord, however, is not 
adherent to the interior of the wall of the canal but is separated from it 
by a considerable interval, the wall being provided with a proper peri- 
osteum. 
The spinal cord is composed of white matter externally and gray mat- 
ter within, and is marked down its middle, both in front and behind, by 
grooves called anterior and posterior median fissures, the posterior being 
much the deeper. The lateral halves of the cord, thus divided, are con- 
nected by a band whose thickness is measured by the interval between 
the bottom of the two median fissures. The front and back of this band 
are made up of white fibres and are called the white commissures of the 
cord; but in the centre the band is gray and is called the gray commis- 
sure. The white commissure connects the white matter on the exterior The Nervous System. 
305 
of each lateral half and the gray commissure, the gray matter of the in- 
terior. This gray matter is placed in the interior of each half in a cres- 
centic form, the convexity of the crescent looking towards the opposite 
half and receiving the gray commissure while the horns of the crescent 
pass, the anterior outward and forward, and the posterior outward and 
backward in the white matter, the posterior horn coming nearer the surface 
than the anterior. Each lateral half of the spinal cord is marked by two 
longitudinal fissures which are much less marked than the anterior and 
posterior median fissures: thus each lateral half is subdivided into three 
columns by the grooves known as the antero-lateral and postero-lateral 
sulci, in contra-distinction to the median fissures. The Spinal Nerves. 
307 
THE SPINAL NERVES. 
Emerging from each lateral aspect of the spinal marrow, and proceed- 
ing as the result of its termination, are nerves called the spinal nerves. 
There are thirty-one pairs of these, consisting of two exactly similar 
nerves placed one on each side. A spinal nerve arises by two roots, one 
from the antero-lateral sulcus of the cord called its anterior or motor 
root, the other from the postero-lateral sulcus and called the posterior or 
sensory root. Soon after its origin the posterior root presents a gangli- 
form enlargement immediately after the formation of which the two roots 
combine to form the nerve which escapes from the spinal canal through 
an inter-vertebral foramen, except the first nerve which makes its exit 
between the atlas and occipital bone, and the last two which leave the canal 
through the aperture at the lower extremity of the sacrum. 
The thirty-one pairs are arranged in groups named from the region of 
the spine in which they emerge. Thus: 
Cervical nerves, consisting of the first eight pairs. 
Dorsal nerves, consisting of the next twelve pairs. 
Lumbar nerves, consisting of the next five pairs. 
Sacral nerves, consisting of the next six pairs. 
It is sometimes said that the last six pairs consist of five sacral and one 
coccygeal. 
Immediately after each nerve has emerged from the spinal canal it 
divides into two branches or cords, one, the posterior, intended to supply 
the structures of the back, and as these are of small importance the pos- 
terior cords will be no further considered. The other branches, called 
the anterior cords, are of vast importance as they supply all the struc- 
tures on the front of the body and the extremities. In all the regions of 
the spine, except the dorsal, the nerves before proceeding to their distri- 
bution inter-communicate and form separate intricate net-works in the 
various regions called plexuses, from which branches pass to supply the 
parts for which the nerves are intended. Four or five nerves usually 
unite to form a plexus. The first plexus formed by the spinal nerves is 
the cervical. Notes on Anatomy. 
The Cervical Spinal Nerves. 
The cervical nerves are eight pairs, the anterior cords of which go, for 
the upper four, to the cervical plexus, and the lower four the brachial 
plexus. The posterior cords go to the structures at the back of the neck. 
The Cervical Plexus. 
The cervical plexus is formed by the intercommunication of the anterior 
cords of the four upper cervical nerves, and is found beneath the middle 
of the sterno-cleido-mastoid muscle. Its principal distribution is to the 
muscles and integument of the neck. The branches are divided into a 
superficial set to the skin and a deep set to muscles. 
The superficial branches are the four following : 
I. Superficialis Colli. 
Second and Third Cervical. 
The superficialis colli emerges around the posterior border of the 
sterno-cleido-mastoid muscle about its middle and runs forward and up- 
ward on that muscle to be distributed to the integument of the front of 
the neck as high as the chin giving off in its course a descending branch. 
11. Auricularis Magnus. 
Second and Third Cervical 
The auricularis magnus branch comes out about the middle of the pos- 
terior border of the sterno-cleido-mastoid muscle, ascends on that muscle 
and is distributed by two branches to the front and back of the ear, 
having giving off filaments to the skin in its course. 
111. Occipitalis Minor—of Second Cervical. 
The occipitalis minor branch ascends parallel with the posterior border 
of the sterno-cleido-mastoid muscle and is distributed on the side of the 
head behind the ear as high as the vertex. 
IV. Descending Superficial Branches of Third and Fourth. 
The descending superficial branches supply the integument of the lower 
part of the neck and crossing the clavicle terminate in the integument of The Spinal Nerves. 
309 
the upper part of the thoracic wall from the sternum to the acromion 
process. These branches are sometimes divided into three sets, sternal, 
clavicular and acromial, the names indicating the direction of the fibres. 
The deep branches of the plexus are three, as follows 
I. Muscular Branches 
The muscular branches supply the praevertebral group of muscles, i. 
e., all the muscles of the neck except the depressors of the hyoid bone. 
11. Communican’s Noni 
The communican’s noni is formed by filaments from the second and 
third nerve, and curving downward and forward communicates with the 
descendens noni, forming Scarpa’s arch, on the front of the sheath of the 
common carotid, from which filaments supply the depressor muscles of 
the hyoid bone, except the thyro-hyoid. 
111. The Phrenic Nerve 
The phrenic nerve is formed by contributions from the third and fourth 
cervical nerves and these, after descending a short distance, are reinforced 
by a filament from the fifth. The course of the nerve on the two sides 
is different. Descending on the front of the scalenus anticus muscles on 
the right side it generally slips to the inner side of that muscle and 
crosses in front of the first portion of the right subclavian artery, be- 
tween it and its vein, and continues its downward course in the thorax, 
beside the right vena innominata and the superior vena cava, passes in 
front of the root of the right lung, thence onward between the pleura and 
pericardium and finally pierces the diaphragm and is distributed to it 
from its under surface. The left nerve differs from this in but two par- 
ticulars, it enters the chest lying on the first portion of the subclavian 
artery and then crosses the arch of the aorta, its course thence being the 
same as the right, except that it has no relation to the left vena innomi- 
nata or the superior vena cava. Occasionally the right nerve does not 
get to the inner side of the scalenus anticus muscle until it has passed the 
subclavian, in which case it crosses the second portion of that artery. 
Brachial Plexus. 
The brachial or axillary plexus is the second, formed by the anterior 
cords of the spinal nerves. It is the result of the inter-communications 310 
Notes on Anatomy. 
between the four lower cervical nerves (fifth, sixth, seventh and eighth) 
and the greater portion of the first dorsal. The manner of its formation 
is as follows: the fifth and sixth cervical unite at once, and the cord thus 
formed is soon joined by the seventh cervical; the eighth cervical and 
first dorsal unite to form one cord, and thus at one time there are but 
two cords in the plexus, but soon these two each give off a branch, and 
these branches unite to form a third cord. The course of the plexus is 
downward and outward; it first lies between the two scaleni muscles and 
then lies in relation with the second and third portions of the subclavian 
artery above and to its outer side; it then comes into relation with the 
axillary artery, lying first to its outer side, then to the outer side and be- 
hind, then to the outer side, behind and to the inner side, and finally, the 
two lateral cords each produce a branch and these unite over the front of 
the artery to form the median nerve and the artery is entirely enveloped. 
The median is formed on the front of the commencement of the third 
portion of the axillary, and the plexus here breaks up into its terminal 
branches. This point about corresponds to the coracoid process of the 
scapula. 
Branches. 
The distribution of the brachial plexus is chiefly to the upper extremity’ 
supplying its muscles and skin; but before reaching the upper extremity 
it gives off some muscular branches. The branches of the plexus are 
divided into two sets, muscular and terminal. 
Muscular Branches 
As the brachial plexus is crossing with the subclavian and axillary 
arteries it gives off numerous filaments to neighboring muscles, viz; the 
scaleni, rhomboid and subclavius, which are collectively known as the 
superior muscular branches. Besides these there are other muscular 
branches bearing specific names, as follows: 
Supra-Scapular Branch. 
The supra-scapular branch arises from the outer cord, passes outward 
to gain the dorsum of the scapula, through the supra-scapular notch, 
and be distributed to the supra and infra spinati. 
Anterior Thoracic Nerves. 
The anterior thoracic nerves arise the one from the outer and the other The Spinal Nerves. 
311 
from the inner cord, and after forming a loop of communication over the 
axillary artery are distributed to the pectoral muscles. 
Posterior Thoracic Nerve. 
Fifth and Sixth Cervical. 
The posterior thoracic nerve, or external respiratory, is the nerve for 
the serratus magnus muscle. It is formed by a filament from the fifth 
and another from the sixth cervical nerves, and descending behind the 
axillary vessels is distributed to the serratus magnus. 
Subscapular Branches. 
Posterior Cord, 
The subscapular are three branches which go to the subscapularis, 
teres major and latissimus dorsi muscles. 
Terminal Branches. 
The terminal branches of the plexus are seven in number, as follows; 
musculo-cutaneous, internal cutaneous, lesser internal cutaneous, median 
ulnar, musculo-spiral and posterior circumflex. They arise in the follow- 
ing manner: the internal cord produces the internal cutaneous, lesser in- 
ternal cutaneous, ulnar and one head of the median, the external cord 
produces the musculo-cutaneous, and one head of the median, the poste- 
rior cord gives rise to the musculo-spiral and posterior circumflex. 
I. Musculo-Cutaneous Nerve. 
The musculo-cutaneous pierces the coraco-brachialis and passes down- 
ward and outward between the biceps and brachialis anticus muscles to 
become superficial at the outer side of the front of the elbow, where it 
divides into two cutaneous branches (external cutaneous) which are dis- 
tributed to the integument of the outer side and outer portion of the 
front of the forearm as far as the wrist. Besides its terminal distribution 
it supplies the coraco-brachialis, biceps and brachialis anticus muscles. 
11. Internal Cutaneous Nerve. 
The internal cutaneous nerve descends to the inner side of the axillary 
and brachial arteries and about the middle of the arm pierces the deep 312 
Notes on Anatomy. 
fascia to become superficial and divides into branches which are distribu- 
ted to the inner side and inner part of the front of the forearm as far as 
the wrist. It gives filaments also to supply the integument of the front 
of the arm. 
111. Lesser Internal Cutaneous Nerve 
The lesser internal cutaneous nerve, or nerve of Wrisberg, descends 
the inner side of the arm and divides into filaments which are lost in the 
integument of the lower third of the posterior aspect of the arm. It is 
the smallest of the terminal branches of the plexus and is soon exhausted. 
It communicates with the lateral cutaneous branch of the second inter- 
costal nerve, or intercosto-humeral. 
IV. Median Nerve. 
The median nerve arises by two roots, one from each lateral cord of 
the plexus, which unite in front of the axillary artery just in front of the 
pectoralis minor muscle. It descends first to the outer side of the axil- 
lary, then to the outer side of the brachial artery, and then crossing the 
brachial about the middle of the arm, usually in front, it passes to the 
inner side of the brachial, which relation it maintains to the elbow when 
it first earns the name median, being here for the first time in the middle 
of the limb. From its origin to the elbow it is superficial; entering the 
forearm it becomes deep, for passing into it between the two heads of the 
pronator radii teres, it descends the forearm beneath the flexor sublimis 
digitorum and enters the palm of the hand beneath the anterior annular 
ligament where it divides into terminal branches which are distributed as 
follows: two to supply the sides of the palmar aspect of the thumb, one 
to the radial side of the index finger, one which divides to supply ad- 
jacent sides of the index and middle fingers, one for the adjoining sides 
of the ring and middle fingers and a muscular branch which supplies the 
following muscles of the thenar eminence: abductor pollicis, flexor ossis 
metacarpi pollicis and the superficial head of the flexor brevis pollicis (z. 
£., all the muscles arising from the trapezium and annular ligament). 
Until it reaches the elbow the median emits no branches. While at the 
elbow and lying beneath the aponeurotic slip of the biceps it produces a 
number of muscular branches which supply all the muscles of the front 
of the forearm except one and a half, i. e., flexor carpi ulnaris and the 
ulnar half of the flexor profundus digitorum, which are supplied by the 
ulnar nerve. The branch to the pronator quadratus descends on the The Spinal Nerves. 
front of the interosseous membrame from the elbow and is called the an- 
terior interosseous nerve. At the lower part of the forearm the median 
gives off a cutaneous branch which descends in front of the anterior an- 
nular ligament to the skin of the palm. 
V. Ulnar Nerves. 
The ulnar nerve descends at first to the inner side of the axillary and 
brachial arteries, but as it passes down the inner side of the arm it di- 
verges from the brachial artery, making for the inner side of the back of 
the elbow where it lies in the groove between the internal condyle and 
the olecranon, forming what is called the funny bone. It enters the fore- 
arm between the two heads of the flexor carpi ulnaris muscle and at the 
commencement of the middle third of the forearm comes into relation 
with the ulnar artery and, lying to the inner side of that vessel, enters the 
palm of the hand and divides into a superficial and a deep palmar branch. 
The superficial palmar branch supplies the palmaris brevis, the integu- 
ment of the inner side of the hand and then divides into two branches, 
one of which supplies the inner side of the little finger and the other, 
after giving off a communication to the median, divides to supply the 
adjacent sides of the little and ring fingers. The deep branch disappears 
between the abductor minimi digiti and flexor brevis minimi digiti and 
supplying the muscles of the hypothenar eminence passes across the 
palm with the deep palmar arch and is distributed to one muscle and a 
half of the thenar eminence, adductor pollicis and deep head of the 
flexor brevis pollicis. On the forearm the ulnar nerve emits the following 
branches: 
ist. Muscular branches to the flexor carpi ulnaris and the ulnar half 
of the flexor profundis digitorum. 
2d. An unimportant cutaneous branch which descends superficially 
into the palm to be lost in the skin. 
3d. A dorsal cutaneous branch which arises about two inches above 
the wrist and passes backward beneath the tendon of the flexor carpi 
ulnaris muscle to the dorsum of the hand where it communicates with 
the radial nerve and divides into branches which supply the integument 
of the inner portion of the dorsum and two fingers and a half, viz: the 
little and ring fingers and the ulnar side of the middle finger. 
VI. Musculo-Spiral Nerve. 
The musculo-spiral springs from the posterior cord of the brachial 
plexus, and is the largest cord of that plexus. It passes downward and Notes on Anatomy. 
outward behind the humerus between it and the triceps muscle, lying in 
the musculo-spiral groove on the posterior surface of the humerus, until 
it reaches the space between the spinator longus and brachialis anticus 
and then descends to the outer side of the front of the elbow, where it 
divides into two branches, radial and posterior interosseous. Besides its 
two terminal branches the musculo-spiral gives off cutaneous branches 
which supply one the front and one the back of the arm and one the 
back of the forearm. It also gives branches to the following muscle's: 
triceps, brachialis anticus, supinator longus, extensor carpi radialis lon- 
gior and anconeus. 
i. The Radial Nerve. 
The radial nerve, derived from the musculo-spiral at the outer side of 
the front of the elbow, descends the radial side of the front of the fore- 
arm lying at first too remotely to the outer side of the radial artery to be 
considered a relation of it, but coming into relation with it at the middle 
third of the forearm and lying to its outer side until it reaches the lower 
third, about three inches above the wrist, when it seeks the back of the 
forearm by passing beneath the tendon of the supinator longus and 
divides into an outer branch, which supplies the two sides of the thumb, 
and an inner branch, which supplies the index finger and radial side of 
the middle finger. The radial nerve communicates with the dorsal branch 
of the ulnar on the dorsum of the hand. 
2. Posterior Interosseous Nerve, 
The posterior interosseous branch of the musculo-spiral immediately 
pierces the supinator brevis muscle to reach the back of the forearm and 
then descends between the superficial and deep layers of muscles, being 
distributed to all the muscles of the back of the forearm except the three 
supplied by the musculo-spiral, supinator longus, extensor carpi radialis 
longior and anconeus. 
VII. Posterior Circumflex Nerve. 
The posterior circumflex nerve, arising from the posterior cord of the 
brachial plexus, winds around behind the surgical neck of the humerus, 
in company with the posterior circumflex artery, and is distributed by an 
upper branch to the deltoid muscle, and by a lower branch to the teres 
minor and the integument covering the shoulder. The Spinal Nerves. 
315 
Dorsal Spinal Nerves. 
The dorsal spinal nerves are twelve pairs, the posterior branches of 
which are distributed to the structures of the back, while the anterior 
cords form the intercostal nerves, and, unlike other spinal nerves, do not 
form a plexus but are distributed separately. 
The Intercostal Nerves. 
The intercostal nerves are the anterior cords of the twelve dorsal 
nerves, and derive their name from their course forward between the ribs. 
The first dorsal nerve sends almost all its bulk to the brachial plexus, and 
the twelfth usually given a branch to the lumbar plexus. The intercostal 
nerves are intended for the supply of the muscles among which they 
course, and of the integument of the front and sides of the thorax and 
abdomen. Each intercostal nerve runs forward in the intercostal space 
between the intercostal muscles to near the edge of the sternum where it 
turns forward and becomes superficial, being called the anterior cuta- 
neous. It is then distributed to the integument of the front of the chest 
and abdomen, most of the filaments passing outward in a recurrent 
course. The six upper nerves appear as the anterior cutaneous through 
the corresponding intercostal spaces, while the six lower pierce the 
sheath of the rectus muscle, and are called the anterior cutaneous of the 
abdomen. After reaching the extremities of the intercostal spaces these 
last nerves pass on between the broad muscles of the abdomen, and the 
last one, though called intercostal, is really not one since it lies below the 
last rib. Whilst running forward the intercostal nerves supply the inter- 
costal muscles and the broad muscles of the abdomen, and about midway 
its course each nerve gives off' a branch called lateral cutaneous, which 
divides into two, one branch passing forward and the other backward, 
both being distributed to the integument of the side of the chest or 
abdomen. The first intercostal nerve, owing to the fact that most of the 
cord from which it is derived goes to the brachial plexus, gives off no 
lateral branch, and to compensate for this delinquency the lateral cuta- 
neous branch of the second nerve is remarkably large, and not only fulfils 
the office of the lateral cutaneous branches for itself and the first, but 
under the name of intercosto-humeral, passes into the axilla, where it 
communicates with the lesser internal cutaneous. The lateral cutaneous 
branch of the twelfth nerve descends over the crest of the ilium, and is 
distributed to the integument of the gluteal region. 316 
Notes on Anatomy. 
The Lumbar Spinal Nerves. 
The lumbar spinal nerves are five pairs, the posterior cords of which 
supply the structures of the back in their region, while the anterior cords 
have the following disposition; The upper four, usually with a branch 
from the twelfth dorsal, constitute by their communication the lumbar 
plexus. The fifth, having been joined by the communicating branch 
from the lumbar plexus, descends into the pelvis (under the name of 
lumbo-sacral cord) to join the sacral plexus. 
The Lumbar Plexus. 
The lumbar plexus is formed by the intercommunication of the anterior 
cords of the four upper lumbar nerves, usually aided by a branch from 
the twelfth dorsal. It lies entangled in the back part of the psoas mag- 
nus muscle and behind that muscle. It is distributed to all of the thigh, 
except the posterior femoral region, to the inner side of the leg and foot 
and to the lowest part of the anterior abdominal parietes, by the following 
branches: ilio hypogastric, ilio-inguinal, external cutaneous, anterior 
crural, genito-crural, obturator and a communicating branch to the sacral 
plexus. Although this is the order in which the branches spring from 
the plexus from above downward, it will be more convenient to describe 
them in a, somewhat different order. The first three branches have a 
course outward and downward, one above the other, across the posterior 
wall of the abdomen and disappear from it on its lateral aspect. 
I. Ilio-Hypogastric Nerve. 
First Lumbar. 
The ilio hypogastric branch passes outward across the quadratus lum- 
borum muscle to pierce the transversalis muscle, and run forward piercing 
successively the internal and external oblique to become cutaneous just 
above the external abdominal ring, beside the linea alba, and be distri- 
buted to the integument of the hypogastric region, having furnished on 
its route branches to the broad muscles of the abdomen and given off a 
branch called iliac, which descends over the crest of the ilium to supply 
the skin of the hip. The Spinal Nerves. 
317 
11. Ilio inguinal Nerve. 
First Lumbar. 
The ilio-inguinal passes outward parallel with and a little below the 
ilio-hypogastric to pierce the transversalis and the internal oblique and, 
thus gaining the external abdominal ring, escape to supply the integu- 
ment of the scrotum and upper part of the inner aspect of the thigh. On 
its way it gives branches to the broad muscles of the abdomen and com- 
municates with the ilio-hypogastric. 
111. External Cutaneous Nerve. 
Second and Third Lumbar. 
The external cutaneous nerve passes downward and outward, across 
the iliacus internus muscle, to escape into the thigh through the notch 
below the anterior superior spinous process of the ilium, where, after a 
course of a few inches in the thickness of the fascia lata, it becomes 
superficial and is distributed to the integument of the outer front aspect 
of the thigh, by a posterior branch encroaching on the back of the thigh. 
IV. Genito-Crural Nerve. 
First and Second Lumbar. 
The genito-crural branch pierces the psoas magnus muscle from be- 
hind forward and then runs down on the front of that muscle to divide 
just above Poupart’s ligament into two branches, genital and crural. 
The genital branch enters the internal abdominal ring and descends along 
the spermatic canal to be lost in the cremaster muscle or round ligament. 
The crural branch passes beneath Poupart’s ligament to be distributed to 
the integument of the front of the thigh as far as the middle. 
V. Obturator Nerve. 
Third and Fourth Lumbar. 
The obturator nerve passes forward just below the brim of the pelvis, 
in company with the obturator artery, to escape through the upper part 
of the obturator foramen, grooving the under surface of the pubes, and 
divides into an anterior and a posterior branch, which are distributed to 318 
Notes on Anatomy. 
the three adductors and the pectineus and to the obturator externus. 
The posterior branch lies behind the adductor brevis; the anterior 
descends in front of that muscle and is distributed to the integument 
of the inner side of the thigh, furnishing filaments to a plexiform com- 
munication of different nerves over the front of the lower part of the 
femoral artery, called the femoral plexus. 
VI. Anterior Crural Nerve. 
Second, Third and Fourth Lumbar. 
The anterior crural is the largest branch of the lumbar plexus. It de- 
scends in the interval between the iliacus internus and psoas magnus 
muscles and entering the thigh beneath Poupart’s ligament lies about 
one-fourth or one-half of an inch to the outer side of the femoral artery. 
Almost immediately upon entering the thigh it splits into branches which 
may be divided into two sets, a superficial or cutaneous set and a deep or 
muscular set. The cutaneous branches are middle cutaneous, internal 
cutaneous and internal saphenous. 
i. Middle Cutaneous Branches. 
The middle cutaneous branches are distributed to the integument of 
the front of the thigh to the knee, one or more of them piercing the 
sartorius and giving filaments to it. 
2. Internal Cutaneous Branch. 
The internal cutaneous branch passes inward over the femoral artery 
and divides into an anterior and a posterior branch, which are distribu- 
ted to the integument of the inner front aspect of the thigh as far as the 
knee. The posterior branch descends along the posterior edge of the 
sartorius muscle and pierces the fascia lata about the knee. The anterior 
branch becomes superficial about the lower third of the thigh. 
3. Internal Saphenous Branch. 
The internal or long saphenous nerve descends in close contact with 
the outer side of the sheath of the femoral vessels until it reaches Hun- 
ter’s canal, when it becomes superficial to them; it then descends 
between the sartorius and gracilis muscles, and continues its course down 
the inner side of the leg in front of the ankle and along the inner side of The Spinal Nerves. 
319 
the foot as far as the great toe, being distributed to the integument of the 
inner side of the leg, inner side of the foot and inner side of the great 
toe. 
The long saphenous furnishes filaments to the femoral plexus, the 
elements of which are derived from it, from the obturator and from the 
internal cutaneous. Just above the knee the long saphenous gives ofif a 
branch called the cutaneus patellae, which is joined by filaments from 
the external, middle and internal cutaneous nerves, to form an intricate 
intercommunication over the front of the patella called the plexus 
patellae. 
Muscular Branches. 
The muscular branches of the anterior crural are distributed to the 
anterior femoral muscles, i. e. rectus, and two vasti and sometimes the 
pectineus. The sartorius is supplied by the middle cutaneous branches 
as these pierce it, and the tensor vaginae femoris is supplied by the glu- 
teal branch of the sacral plexus. 
VII. Communicating Branch. 
The communicating branch joins the anterior cord of the fifth lumbar 
and descends into the pelvis to aid in forming the sacral plexus, by the 
name of lumbo-sacral. 
The Sacral Plexus. 
The sacral plexus is formed by the fusion of the lumbo-sacral nerve 
with the three anterior cords of the three upper sacral nerves with half 
the anterior cord of the fourth sacral. This plexus differs from others in 
this, that it is not a simple intercommunication, but the elements blend 
into a broad continuous band. The plexus extends from its base formed 
by its roots downward and outward to the great sacro-sciatic foramen, 
where it breaks up into its four terminal branches. It lies on the lateral 
front face of the sacrum and on the front of the pyriformis muscle. The 
distribution of the plexus is to the viscera and walls of the pelvis, to the 
gluteal region, to the posterior femoral region of the thigh, to all the leg 
except the inner side, to all the foot except the inner side, and to all the 
toes except the inner side of the great toe. 
Branches. 
Besides its four terminal branches the sacral plexus produces a set of 
visceral branches to the pelvic viscera, which are in part supplied by 320 
Notes on Anatomy. 
branches derived from that portion of the fourth sacral nerve which does 
not enter into the plexus, and a second set to muscles, viz: the levator 
ani and all the outward rotators of the thigh, except the obturator exter- 
nus, which gets its supply from the obturator nerve. The four terminal 
branches of the plexus are superior gluteal, internal pudic, lesser and 
greater sciatic. 
1. Gluteal Nerve. 
The superior gluteal nerve comes off from the upper part of the 
sacral plexus and leaves the cavity of the pelvis through the greater 
sacro-sciatic foramen, above the pyriformis muscle, and divides into two 
branches, which ramify between the gluteus medius and minimus, being 
distributed to those two muscles and by terminal filaments to the tensor 
vaginae femoris. 
11. Internal Pudic Nerve 
The internal pudic nerve arises from the lower part of the plexus and 
leaves the pelvis through the greater sacro-sciatic foramen, below the 
pyriformis muscle, crosses the spine of the ischium and re-enters the 
pelvis through the lesser sacro-sciatic foramen, dividing into two branches, 
a superior, or dorsalis penis, and an inferior, or perineal, having emitted 
before dividing the inferior hemorrhoidal branch, which is distributed to 
the sphincter ani and the integument around the anus. 
i. Dorsalis Penis Nerve. 
The dorsalis penis branch passes upward and forward along the ramus 
of the ischium and pubes, pierces the suspensary ligament of the penis, 
continues its course forward on the dorsum of the penis, supplying the 
integument and corpus cavernosum and terminates in the glans penis. 
It gives off a lateral cutaneous branch to the side of the organ. 
2. Perineal Nerve. 
The perineal branch divides into two sets of branches, cutaneous and 
muscular. The cutaneous branches are two, anterior and posterior, and 
pass forward being distributed to the integument of the scrotum, peri- 
neum and under surface of the penis. The muscular branches are 
directed to the muscles of the perineum, viz; tranversus perinei, erector 
penis, accelerator urinae and compressor urethrae. Several of the deep 
filaments also supply the corpus spongiosum. The Spinal Nerves. 
321 
111. Lesser Sciatic Nerve. 
The lesser sciatic nerve, usually arising by two roots, escapes through 
the greater sacro-sciatic foramen below the pyriformis muscle along with 
but superficial to the great sciatic nerve, and descends the middle of the 
back of the thigh beneath the fascia lata to terminate on the back of the 
upper part of the leg. 
Branches. 
The branches of the lesser sciatic are chiefly cutaneous but it supplies 
one mifscle, the gluteus maximus. The cutaneous distribution comprises 
the filaments distributed to the integument in the downward course of 
the nerve on the back of the thigh and upper part of the back of the 
leg, and may be called descending cutaneous branches. Secondly, it 
sends cutaneous branches upward to the integument of the lower por- 
tion of the gluteal region, and these are known as ascending cutaneous 
branches. Thirdly, it gives off internal or perineal cutaneous branches 
which supply the integument along the inner posterior aspect of the 
thigh; one of these is known as the inferior pudendal nerve which curves 
upward and forward to communicate with the perineal branch of the 
internal pudic, and aid in supplying the integument of the perineum. 
IV. Great Sciatic Nerve. 
The great sciatic is the longest nerve in the system and seems a contin- 
uation of the plexus through the great sacro-sciatic foramen, below the 
pyriformis muscle, being the last structure which has to be traced through 
that aperture. These structures are eight in number of which the pyri- 
formis muscle is the bulkiest, almost filling the foramen. Besides it there 
are four nerves and three arteries which emerge through the foramen, 
one artery and one nerve passing above the muscle, viz: the gluteal 
artery and nerve, and two arteries and three nerves passing below, viz: 
the internal pudic and ischiatic arteries and the greater and lesser sciatic 
and internal pudic nerves. 
After escaping the great sciatic descends the middle of the back of the 
thigh, lying on the adductor magnus muscle beneath the biceps which 
separates it from the lesser sciatic. It divides usually, at the upper angle 
of the popliteal space, into the internal and external popliteal nerves; 
but it may divide before reaching that point and its two terminal branches 
may even come off separately from the plexus. Before dividing it gives 
off branches to the posterior femoral muscles and to the adductor 
magnus. 322 
Notes on Anatomy. 
i. Internal Popliteal Nerve. 
The internal popliteal nerve descends through the popliteal space to 
pass beneath the tendinous arch of the soleus muscle and there become 
the posterior tibial nerve. It is a relation of the popliteal artery, lying, 
for the upper two-thirds of that vessel, superficial and external to it and 
then crossing superficially to its inner side, which relation it maintains to 
the termination of both. 
Branches. 
The internal popliteal gives off muscular branches to the triceps surae 
and to the popliteus muscle, besides which it produces a cutaneous 
branch called the external saphenous. The branches to the popliteus 
run to its lower border and then turn upward to the under surface of the 
muscle. 
The External Saphenous Nerve. 
The external or short saphenous nerve descends from the internal pop- 
liteal in company with the external saphenous vein, lying first in the 
groove between the two heads of the gastrocnemius muscle, then beside 
the outer edge of the tendo Achilles and, passing behind the external 
malleolus, runs forward on the outer side of the dorsum of the foot to the 
little toe. About the middle of the back of the leg it is joined by a 
branch of the external popliteal called the communicans peronei. The 
external saphenous is distributed to the integument of the outer side of 
the heel, outer side of the dorsum of the foot and outer side of the little 
toe. 
Posterior Tibial Nerve 
The posterior tibial nerve, the continuation of the internal popliteal, 
begins at the tendinous arch of the soleus, descends the back of the leg 
lying beneath the triceps surae and terminates midway between the pos- 
terior tuberosity of the os calcis and the internal malleolus by dividing 
into the internal and external plantar nerves. The posterior tibial nerve 
is a companion of the posterior tibial artery, lying at first to its inner 
side, but crossing it superficially after a course of a few inches to become 
a continuous external relation. 
Branches. 
Besides its terminal branches the posterior tibial nerve gives off mus- 
cular branches to the deep layers of muscles on the back of the leg The Spinal Nerves. 
323 
except the popliteus and a cutaneous branch, called the internal calcanean, 
to the integument of the heel. 
The Internal Plantar Nerve 
The internal plantar nerve runs forward between the abductor pollicis 
and flexor brevis digitorum and divides into four branches, which are dis- 
tributed as digital branches to the inner side of the great toe, the adjacent 
sides of the great and second, second and third toes and the inner side 
of the fourth toe. Besides these the nerve emits cutaneous branches to 
the integument of the inner side of the sole and muscular branches to 
muscles in its course, viz: abductor pollicis, flexor brevis digitorum and 
flexor brevis pollicis. Finally, the digital branches furnish filaments to 
the two inner lumbricales. 
The External Plantar Nerve 
The external plantar nerve takes the course of the external plantar 
artery, running at first outward on the musculus accessorius and then 
forward between the flexor brevis digitorum and abductor minimi digiti, 
it divides into two digital branches which supply the little toe and outer 
side of the fourth toe. This digital distribution is exactly similar to the 
ulnar nerve in the hand, while that of the internal plantar is the counter- 
part of the median nerve. Besides its digital branches the external plan- 
tar gives off filaments to the integument of the outer side of the sole and 
branches to the muscles in its course, viz: musculus accessorius, abductor 
minimi digiti, flexor brevis minimi digiti, two outer lumbricales and two 
outer interossei, sends a communication to the internal plantar and lastly 
gives off a branch which accompanies the plantar arch and supplies the 
adductor pollicis, transversus pedis and all the interosseous muscles 
except those in the outer metatarsal space. 
2. External Popliteal Nerve. 
The external popliteal nerve, very much smaller than the internal, 
passes outward and ■ downward from its origin as one of the terminal 
branches of the great sciatic, and crossing the outer head of the gastroc- 
nemius muscle enters the substance of the peroneus longus and just be- 
low the head of the fibula divides into two branches, anterior tibial and 
musculo cutaneous. 
Branches. 
Besides the terminal branches, the external popliteal emits cutaneous 324 
Notes on Anatomy. 
filaments to supply the integument of the outer side of the leg, and a 
communicating branch to the external saphenous which is called com- 
municans peronei. 
Communicans Peronei. 
The communicans peronei leaves the external popliteal near the head 
of the fibula and crossing downward and inward on the back of the leg 
joins the external saphenous about the middle of the leg, having given 
filaments to the integument in its course. 
Anterior Tibial Nerve. 
The anterior tibial branch of the external popliteal nerve passes inward 
through the fibres of the extensor longus digitorum m uscle to gain the outer 
side of the anterior tibial artery with which it descends the front of the 
leg lying first to the outer side, then in front and then again to the outer 
side of the artery, first on the interosseous membrane and then on the 
front of the tibia. Having reached the termination of the anterior tibial 
artery it passes forward on the dorsum of the foot lying to the outer side 
of the dorsalis pedis artery and where that artery terminates, at the base 
of the first metatarsal space, it also divides into two branches which supply 
the adjacent sides of the dorsal aspect of the great and second toes. 
Branches. 
Besides its two terminal branches the anterior tibial nerve produces 
muscular branches to the muscles in its course, viz: those of the anterior 
tibial region and the extensor brevis digitorum, the latter muscle being 
supplied by a branch which passes outward on the tarsus to be distributed 
to it and to the articulations. 
Musculo-Cutaneous Nerve. 
The musculo-cutaneous nerve, the second terminal branch of the ex- 
ternal popliteal, descends in and among the muscles of the external 
region of the leg, lying first in the peroneus longus, then between it and 
the peroneus brevis and then between the two peronei and the extensor 
longus digitorum, and at the lower third of the outer aspect of the leg 
pierces the deep fascia and thus becoming superficial is distributed to the 
dorsum of the foot by two branches, inner and outer, not only supplying 
the integument of the dorsum of the foot but giving digital branches to The Spinal Nerves. 
325 
the adjacent sides of the second and third, third and fourth, and fourth 
and fifth toes, the inner branch giving off a twig which aids the internal 
saphenous in supplying the inner side of the great toe. Whilst coursing 
among the peronei it also supplies those two muscles. 
Nervous Supply to the Dorsum of the Foot. 
The nervous supply to the dorsum of the foot is chiefly derived from 
the musculo-cutaneous, but it is aided on the inner side of the dorsum and 
on the inner side of the great toe by the long saphenous, while the outer 
side of the little toe is supplied by the short saphenous, and the adjacent 
sides of the great and second toes are supplied by the termination of the 
anterior tibial. 
Fourth, Fifth and Sixth Sacral Nerves. 
The fourth sacral nerve sends half its bulk to aid in forming the sacral 
plexus. Of the other half a part goes to furnish visceral branches to the 
pelvic viscera and a part aids the small fifth and sixth nerves in supply- 
ing the coccygeus and levator ani muscles and the integument over the 
coccyx and between it and the anus. 
Sympathetic Nerves. 
The sympathetic nervous system consists of a vertebral and a cranial 
portion. 
The Vertebral Portion. 
The vertebral portion of the sympathetic consists of two similar series 
of ganglia, lying one on each side of the vertebral column, extending 
from the skull to the coccyx, and the nerves which are connected with 
these ganglia. Of these ganglia there are about twenty-four divided 
into cervical, of which there are three, dorsal, of which there are twelve, 
lumbar, of which there are four or five and sacral, of which there are 
about four. Each ganglion is provided with four sets of branches: 
ist, ascending to connect it with the ganglion above; 2d, descending to 
connect it with the ganglion below; 3rd, external to connect it with a 
contiguous spinal nerve; 4th, internal or branches of distribution. The 
first three sets of branches are the communicating branches, and each of 
the connections, viz : with the ganglion above, the ganglion below and 
the spinal nerves, is effected by two filaments, one of which is gray and 
the other white. The fourth set of branches, the internal or distributing, 326 
Notes on Anatomy. 
pass, as a rule, inward and forward to supply the organs of their various 
regions; these branches going either singly to their destination, or, as in 
some cases, several branches from one side meet similar ones from the 
opposite side and communicating with them on the front of the vertebral 
column, form plexuses from which the branches of distribution proceed. 
Three of these plexuses exist, known as the cardiac, solar and hypogas- 
tric, these constituting what is called the praevertebral sympathetic. As 
a rule each ganglion is connected with but one spinal nerve, but to this 
there are exceptions, which will be found in the cervical portion. 
Cervical Portion 
The cervical portion of the sympathetic is that part of the chain or 
trunk which is found in the cervical region. Although there are eight 
cervical spinal nerves, there are only three sympathetic ganglia, known 
respectively as superior, middle and inferior. 
Superior Cervical Ganglion. 
The superior cervical ganglion lies on the front lateral aspect of the 
second and third cervical vertebrte, being of a fusiform shape and pinkish 
color. 
Its external branches connect it with the first four cervical spinal 
nerves and also with three of the cranial nerves, viz: glosso-pharyngeal, 
pneumogastric and hypoglossal. 
Its ascending branches pass up along the internal carotid artery, one 
on the inner side of that vessel to form the cavernous plexus by com- 
munications in the cavernous sinus; the other, on the outer side of the 
artery to form the carotid plexus. 
Its descending branches connect it with the middle cervical ganglion. 
This ganglion gives off branches from its front face which twine around 
the external carotid artery and are called nervi molles. 
The internal branches, or branches of distribution, are three, as fol- 
lows : 
ist. Pharyngeal, which join in the pharyngeal plexus. 
2d. Laryngeal, which are distributed to the larynx. 
3d. Superior cardiac, distributed to the heart in a manner which will 
hereafter be explained. This is called the superior cardiac because each 
of the three cervical ganglia give off a cardiac branch which are distin- 
guished as superior, middle and inferior. The Spinal Nerves. 
327 
Middle Cervical Ganglion. 
The middle cervical ganglion is situated opposite the fifth cervical ver- 
tebra, is small and sometimes altogether wanting. 
Its external branches communicate with the fifth and sixth cervical 
spinal nerves. 
Its ascending and descending branches connect it with the superior and 
inferior cervical ganglia respectively. 
Its branches of distribution are two; 
ist. Middle cardiac; 2d, thyroid, which joins the inferior thyroid 
artery just where it makes its inward turn and accompanies it to the thy- 
roid gland. 
Inferior Cervical Ganglion. 
The inferior cervical ganglion lies opposite the seventh cervical verte- 
bra. Its external branches connect it with the seventh and eighth cer- 
vical spinal nerves. 
Its ascending branches bring it into connection with the middle cervical 
ganglion. 
Its descending branches are to the first dorsal ganglion. Its branches 
of distribution are as follows: 
ist. Inferior cardiac; 2d, a branch which comes off from the outer side 
of the ganglion and forms a plexus along the vertebral artery. 
The Cardiac Nerves. 
The cardiac branches from the cervical sympathetic are three on each 
side, superior, middle and inferior. Proceeding from their respective 
ganglia they descend into the thorax and form the cardiac plexus, the 
first of the praevertebral plexuses. 
The cardiac plexus consists of two portions, a superficial, or the lesser 
cardiac plexus and a deep, or the greater cardiac plexus. 
The superficial portion is found on the ductus arteriosus, is quite small 
and often contains a ganglion. It is formed by the superior cardiac nerve 
of the left side and by the cardiac branch of the pneumogastric. The 
deep portion, very much larger than the superficial, is situated in the 
bifurcation of the trachea and is formed by the three cardiac nerves of 
the right side and the middle and inferior cardiac nerves of the left side 
with the cardiac branches of the right pneumogastric. From these two 
portions, which are connected by a communicating branch, filaments de- 328 
Notes on Anatomy. 
scend to the heart along the anterior coronary artery, the anterior coro- 
nary plexus, and along the posterior coronary artery, the posterior 
coronary plexus. 
Thoracic or Dorsal Sympathetic. 
The dorsal portion of the sympathetic consists of twelve ganglia on 
each side connected by ascending and descending branches with contigu- 
ous ganglia. Each ganglion lies on the front of the head of a rib, and 
besides its ascending and descending branches of communication is con- 
nected with a neighboring spinal nerve. 
The internal branches of the dorsal ganglia have the following distri- 
bution: Those from the upper five ganglia (about) are furnished to the 
aorta and the oesophagus, giving a few filaments to the lungs and heart. 
The internal branches from the lower seven descend to the abdomen, as 
they are not needed in the thorax, forming as they do so what are known 
as the splanchnic nerves, whose formation and destination are as follows: 
the internal branches from the sixth, seventh, eighth and ninth and a part 
of those from the tenth dorsal ganglia unite successively to form a large 
cord called the greater splanchnic nerve, wnich pierces the crus of the 
diaphragm and terminates in a ganglionic body called the semilunar 
ganglion. The two semilunar ganglia, right and left, surround the cceliac 
axis and give off an immense number of branches, which, radiating like 
rays of the sun, constitute the solar plexus. The internal branches of the 
eleventh dorsal ganglion and part of that of the tenth unite to form the 
lesser splanchnic which descends to pierce the diaphragm and terminate 
in the semilunar ganglion of that side. The internal branches of the 
twelfth dorsal ganglion, usually aided by a branch from the lesser 
splanchnic, form the least splanchnic nerve which proceeds to the kidney. 
The branches of distribution of the semilunar ganglia forming the solar 
plexus are intended to supply the abdominal viscera and walls. The 
nerves proceed along the artery to any viscus and are known as plexuses 
which bear the name of the artery they accompany. The plexuses are 
accordingly as many as the arteries to the abdomen. 
ist. The phrenic plexus accompanies the phrenic artery to the dia- 
phragm. 
2d. The gastric plexus, accompanying the various gastric arteries to 
the stomach. 
3d. The hepatic plexus, accompanying the hepatic artery to the liver. 
4th. The splenic plexus accompanying the splenic artery to the spleen. The Spinal Nerves. 
329 
sth. The supra-renai plexus, accompanying the supra-renal artery to 
the supra-renal gland. 
6th. The renal plexus, accompanying the renal artery to the kidney. 
yth. The superior mesenteric plexus, accompanying the superior me- 
senteric artery to the small intestine. 
Bth. The spermatic plexus, accompanying the spermatic artery to the 
testes. 
9th. The inferior mesenteric plexus, accompanying the inferior mesen- 
teric artery to the large intestine. 
10th. The aortic plexus, which descends along the aorta and after pro- 
ducing by most of its bulk the inferior mesenteric plexus continues into 
the pelvis to aid in forming a prsevertebral plexus on the front of the 
sacrum known as the hypogastric. 
The renal and supra-renal plexuses are remarkable for the large size 
and number of their nerves, the kidney receiving some fifteen large fila- 
ments. 
The Lumbar Sympathetic 
The lumbar portion of the sympathetic system is continuous above 
with the dorsal by means of branches which pass beneath the ligamentum 
arcuatum externum, inferiorly its descending branches communicate with 
the sacral portion. Besides the ascending and descending branches each 
ganglion, of which there are four or five found lying along the inner 
edge of the psoas magnus muscle, has external branches to a lumbar 
spinal nerve. Of the internal branches the upper pass to the aortic 
plexus and the lower descend to the front of the promontory of the 
sacrum where they join the hypograstric plexus which is distributed to 
the pelvic viscera by plexuses accompanying the branches of the internal 
iliac artery. 
Sacral Sympathetic 
The sacral portion of the spmpathetic consists of four or five ganglia 
with the usual communicating branches and with branches of distribution 
to aid the hypograstric plexus in supplying the pelvic viscera. These 
ganglia lie on the front of the lateral aspect of the sacrum near the ante- 
rior sacral foramina, the ganglia of each side approaching below until 
the last pair, meeting in the middle line, fuse into one called the ganglion 
imprar. 330 
Notes on Anatomy. 
The Cranial Sympathetic. 
The cranial portion of the sympathetic consists of four ganglia, lying 
in and around the skull, with their branches of communication and distri- 
bution, and of the carotid and cavernous plexuses formed by the ascend- 
ing branches of the superior cervical ganglion. Each cranial ganglion is 
connected with two cranial nerves or two branches of the same nerve, 
receiving from one a motor and from the other a sensitive branch, and is 
also connected with the rest of the sympathetic system by a communi- 
cating branch. These various communicating branches form the roots of 
the ganglion. The four cranial ganglia are the ophthalmic, the spheno- 
palatine, the otic and the submaxillary. 
Ophthalmic Ganglion 
The ophthalmic or lenticular ganglion is found in the orbit lying on the 
outer side of the optic nerve close to the optic foramen. 
Its sensitive root is furnished by the nasal nerve; its motor root by the 
branch of the third nerve sent to the inferior oblique muscle; its sympa- 
thetic root by the cavernous plexus. 
Its branches of distribution, known as ciliary, five or six in number, 
pierce the sclerotic coat around the optic nerve and ramifying between 
the tunics of the eye-ball terminate in the iris. 
Spheno-Palatine Ganglion. 
The spheno-palatine, or Meckel’s ganglion, is the largest of the cranial 
ganglia and is found lying in the spheno-maxillary fossa just beneath the 
superior maxillary division of the fifth nerve. 
Its sensitive root consists of two filaments from the superior maxillary 
nerve: its motor root is derived from the facial nerve; its sympathetic 
root is from the carotid plexus. The last two roots reach the ganglion 
together, i. e., they are in the same sheath and form apparently one 
nerve; but the motor root, coming from the vidian, separates from the 
other branch of that nerve at the termination of the vidian canal, the other 
branch, the great superficial petrosal nerve, going to the facial through 
the hiatus Fallopii. The branches of distribution of this ganglion are 
four, palatine pharyngeal, superior nasal and naso-palatine. 
ist. The three palatine branches, anterior, middle and posterior, de- 
scend to supply the roof of the mouth, soft palate and tonsils. The The Spinal Nerves. 
331 
anterior descends through the posterior palatine foramen and gives off 
branches which pass forward. One of these (the inferior nasal) enters 
the nasal fossa and is distributed to the mucous membrane of the inferior 
and middle meatuses. 
2d. The pharyngeal branch passes backward through the pterygo- 
palatine canal to be distributed to the mucous membrane of the pharynx. 
3d. The superior nasal are four or five branches which enter the nose 
through the spheno-palatine foramen and are distributed to the superior 
meatus of the nose. 
4th. Naso-palatine enters the nose through the spheno-palatine fora- 
men, runs inward to the septum and, after giving branches to it, enters 
the palate through the naso-palatine canal. 
Otic Ganglion. 
The otic, or Arnold’s ganglion, small and oval-shaped, is situated on 
the inner side of the inferior maxillary branch of the fifth nerve, just 
after its exit through the foramen ovale. Its sensitive root comes from the 
auriculo-temporal branch of the inferior maxillary; its motor root from 
the nerve to the pterygoideus internus; its sympathetic root from the 
plexus on the middle meningeal artery. Its branches of distribution are 
three, as follows: 
Ist. A branch which passes backward to the tensor tympani muscle. 
2d. A branch which passes forward to the tensor palati muscle. 
3d. The nervus petrosus superficialis minor, which first enters the 
cranium through a canal between the foramen ovale and foramen spino- 
sum and passing backward enters the tympanum, to join the tympanic 
plexus, through a canal near the base of the petrous bone. It gives off 
a branch (nerve of Longet) which enters the hiatus Fallopii to join the 
intumescentia gangliformis of the facial nerve. 
The Outlet of the Pelvis. 
The outlet of the pelvis, which in the recent subject, is closed by 
various soft parts, in the skeleton is seen to be surrounded by the follow- 
ing parts : in front it is limited by the pubic arch, behind by the tip of 
the coccyx, on each side, about the centre, by the tuberosity of the 
ischium and running forward from this the rami of the ischium and pubes 
and backward from it the greater sacro-sciatic ligament or, in the recent 
subject, the lower border of the gluteus maximus muscle. In the recent 332 
Notes on Anatomy. 
subject the outlet of the pelvis is divided into two portions by a trans- 
verse line passing between the anterior edges of the two tuberosities of 
the ischia, or, in other words, from the indefinite point on one side where 
the ramus and tuberosity of the ischium meet to a similar point on the 
opposite side. The portion lying in front of this line is called the peri- 
neum and that lying behind it the ischio-rectal region. 
Ischio-Rectal Region. 
The ischio-rectal region is bounded in front by the transverse line, 
behind by the apex of the coccyx, laterally by the great sacro-sciatic 
ligament or the lower edge of the gluteus maximus muscle and the 
tuberosity of the ischium. It contains three parts to be examined, the 
anal orifice with its sphincter muscle and, on each side of this, a sub- 
division known as the ischio-rectal fossa. 
Anus. 
The anus is the termination of the rectum, and is kept habitually closed 
by the tonic contraction of muscles called sphincters internal and external. 
The sphincter ani internus was described with the structure of the rectum, 
it being a muscular ring around the gut formed by an aggregation of its 
circular muscular fibres about an inch above the anal orifice. Surround- 
ing the anal orifice, which is seen in the centre of the ischio rectal region, 
is a thin elliptical muscle called the sphincter ani externus. It arises from 
and around the tip of the coccyx and passes forward just beneath and 
closely adherent to the skin to surround the anal orifice, and be inserted 
in front of it into a point in the centre of the perineal line called the cen- 
tral point of the perineum. 
Ischio-Rectal Fossa. 
The ischio-rectal fossa is the triangular or wedge-shaped space lying 
beside the anus, one on each side. It is about two inches deep, the base 
being at the surface and its limits being indicated by the anus within, the 
tuberosity of the ischium without, the transverse line in front and the 
lower edge of the gluteus maximus muscle behind. The apex is above, 
and is formed by the coming together of two sides of the space, the inner 
side being a muscle, called levator ani, which is inserted into the side of 
the lower part of the rectum, while the outer side is the obturator inter- 
nus muscle. The levator ani muscle is thin and flat and has a most pecu- The Spinal Nerves. 
333 
liar origin, to understand which some preliminary remarks are necessary. 
The transversalis fascia, which lies between the transversalis abdominis 
muscle and the parietal layer of the peritoneum, when it reaches the iliac 
fossa, where it covers the iliacus internus muscle, takes the name of iliac 
fascia, which, in turn, when it reaches the brim of the pelvis, assumes 
the name of pelvic fascia, and this descending into the pelvis when it 
reaches the commencement of the obturator foramen, divides into two 
layers, one of which, the external, passes over the inner face of the ob- 
turator internus, as the obturator fascia; while the other passes to the 
base of the bladder and the side of the rectum as the recto-vesical fascia. 
Now just in the interval left by the splitting of the pelvic fascia the leva- 
tor ani rises, having internal to it the recto-vesical fascia and external, 
with a widening interval between them, the obturator fascia. Besides 
this origin from the fascia, it arises posteriorly from the spine of the 
ischium and anteriorly from the back of the pubes. The ischio-rectal 
region thus described is found filled with adipose tissue, the absorption 
of which, in long-continued, debilitating disease, is the cause of the 
sunken appearance seen there. 
Perineum—In the Male. 
The perineum is that sub-division of the outlet of the pelvis which lies 
in front of the transverse line. Its limits are as follows: In front the 
pubic arch, behind the transverse line, on each side the rami of the pubes 
and ischium. Crossing along its centre from behind forward, and con- 
tinued on to the scrotum, is a ridge of the integument called the raphe. 
Upon careful dissection the perineum is found to be formed of the fol- 
lowing constituents from the surface upward, viz: 
ist. Integument. 
2d, Several layers of superficial fascia which in no wise differ from the 
general superficial fascia found beneath the integument everywhere. 
3d. A layer of fascia called the superficial perineal fascia, since it is 
peculiar to the perineum, being attached to the rami of ischium and 
pubes on each side, in front continuous with the dartos of the scrotum 
and behind attached to nothing but terminating by changing its name, 
at the transverse line making a bend on itself and running back toward 
the pubic arch under tne name of deep perineal fascia. It is separated 
from the superficial perineal fascia by the root of the penis and the mus- 
cles connected with it. 
4th. Removing the superficial perineal fascia there are exposed the Notes on Anatomy. 
root of the penis and its muscles. The root of the penis consists of the 
two crura attached, one on each side, to the rami of the pubes and 
ischium, and of the bulb of the corpus spongiosum, which lies between 
these. 
The muscles which are exposed are three pairs— 
ist. Transversus perinei, which arises on each side from the spot 
where the ramus of the ischium is continued into the tuberosity, and 
passes transversely inward to meet its fellow in the centre. The point 
where the two perinei are inserted into each other is called the perineal 
centre. It should be observed that the course of these muscles corre- 
sponds with the transverse line. 
2d. Accelerator urinae. This muscle arises from the perineal centre 
and from the raphe between it and its fellow. The greater portion of its 
fibres surround the corpus spongiosum to meet the opposing muscle on 
the top of the corpus, but some of the fibres, posteriorly, are inserted 
into the deep perineal fascia and ramus of the pubes, while some in front 
are lost in the corpus cavernosum. Its chief action is to drive the urine 
forward by contracting on the corpus spongiosum, in which is the urethra. 
3d. Erector penis arises from the rami of the ischium and pubes, and 
passing forward is lost on the upper aspect of the corpus cavernosum. 
After removing these muscles and the root of the penis the deep peri- 
neal fascia is displayed. This, as stated, is continuous at the transverse 
line with the superficial perineal fascia, the line of reflection being around 
the posterior aspect of the transverse perineal muscles. From this point 
it passes forward to the arch of the pubes, attached on either side to the 
rami of the ischium and pubes. Just below the arch of the pubes it pre- 
sents a small, round opening for the passage of the urethra. When the 
deep perineal fascia is dissected it is found to consist of two layers, called 
the superficial and deep layers of the deep perineal fascia, which is some- 
times called the triangular ligament of the pubes. Between the two 
layers are found blood vessels and nerves and a pair of muscles called 
compressors urethrae. The compressor urethrae arises from the point of 
union between the rami of the pubes and ischium and running trans- 
versely inward divides into two fasciculi, which meet those of the oppo- 
site side and surround the urethra. Inguinal Hernia. 
335 
INGUINAL HERNIA. 
Inguinal hernia is the protrusion of some portion of the abdominal 
contents through the abdominal wall, making its way along the inguinal 
canal. The parts concerned are the lower fibres of the broad muscles of 
the abdomen, their superficial and deep coverings, and the structures 
composing the scrotum. 
There is no deep fascia investing the broad muscles of the abdomen. 
When the integument is removed, two layers of superficial fascia are 
seen, separated from each other by the superficial blood vessels and 
nerves, the deeper of the two being the stronger. The removal of the 
deep layer exposes the lower portion of the aponeurosis of the external 
oblique muscle, known as Poupart’s ligament, which extends from the 
anterior superior spinous process of the ilium to the spine of the pubes, 
the inner portion forming the outer, or lower, pillar of the external, or 
superficial, abdominal ring. Poupart’s ligament is folded upon itself, 
backward and upward, forming a groove, directed upward and inward. 
To its posterior face is attached the transversalis fascia, where it becomes 
continuous with the iliac, while its anterior face is continuous with the 
fascia lata and has adherent to it the deep layer of the superficial fascia. 
Before reaching the spine of the pubes, Poupart’s ligament sends down- 
ward and backward a mass of fibres, with its base outward and apex 
inward, to be attached to the spine and pectineal line of the pubes, under 
the name of Gimbernat’s ligament. Turning down Poupart’s ligament 
we expose the combined origin of the internal oblique and transversalis 
muscles, which arches upward and inward, muscular, to form the con- 
joined arch, becomes tendinous and arches downward and inward as the 
conjoined tendon, which is inserted into the crest and pectineal line of the 
pubes behind the superficial abdominal ring. The outer abutment of this 
arch is at the middle of Poupart’s ligament, the inner one-half inch ex- 
ternal to the spine of the pubes, while the centre of the arch is one-half 
inch above Poupart’s ligament. Cutting away these structures we come 
to the transversalis fascia, behind which is the parietal layer of the peri- 
toneum, the two being separated by some loose connective tissue and fat. 
In the transversalis fascia is a second opening, called the deep or internal 
abdominal ring. At the lower, inner, part of the aponeurosis of the ex- Notes on Anatomy. 
ternal oblique muscle there is a triangular opening, caused by the diver- 
gence of the fibres of the aponeurosis, known as the superficial or external 
abdominal ring; the apex of the opening being directed upward and 
outward, its base downward and inward and corresponding to the crest 
of the pubes. The lateral boundaries of this ring are known as its pil- 
lars—internal, or superior, attached to the front of the symphysis pubis, 
external, or inferior, attached to the spine of the pubes. The latter is 
simply the inner portion of Poupart’s ligament. Around the margins of 
this ring the deep layer of the superficial fascia is attached, forming what 
is called the inter-columnar fascia. The two layers become continuous 
below with the dartos of the scrotum. The apex of the triangle is ob- 
scured by a few fibres which cross the others at right angles and prevent 
a further divergence of the fibres and consequent widening of the tri- 
angle. These are called the inter-columnar fibres. 
About one and one-half inches above and external to this opening, 
nearly opposite the centre of Poupart’s ligament, there is a hole in the 
transversalis fascia called the deep or internal abdominal ring, situated a 
little less than one-half an inch above Poupart’s ligament and internal to 
the outer abutment of the arch. Externally this ring is bounded by the 
conjoined arch, internally by the deep epigastric artery, below by Poupart’s 
ligament. The ring does not exist in a healthy subject. Through this 
ring the testicle descends in the foetus, and to its margins is attached a 
prolongation of the transversalis fascia, the infundibuliform tube of fascia, 
which forms one of the coats of a hernia. Extending between the two 
rings there is a canal, about one and one-half inches long, the inguinal or 
spermatic canal, which, in health, transmits the spermatic cord, in the 
male, or the round ligament, in the female, while, pathologically, it trans- 
mits the gut in a hernia. 
The spermatic canal is limited internally by the superficial abdominal, 
externally by the deep, abdominal ring, and its walls are formed as fol- 
lows; Below by the grooved upper surface of Poupart’s ligament; above 
by the conjoined arch; in front by the aponeurosis of the external oblique; 
behind, by the transversalis fascia and parietal layer of peritoneum 
throughout its extent, while, for about its inner half, the conjoined tendon 
lies in front of those structures. The canal contains the neck of the 
infundibuliform tube of fascia, arteries, nerves, lymphatics and the duct 
from the testicle. 
On the visceral face of the peritoneum there may sometimes be seen a 
dimple which corresponds to the deep abdominal ring, and, internal to 
this, a ridge which is formed by the deep epigastric artery. The space Inguinal Hernia. 
337 
between the ridge and the mid line of the body is called the internal 
inguinal fossa, that external to the ridge, the external inguinal fossa. 
The testicles, in their descent, enter at the deep ring, pass through the 
inguinal canal and make their exit at the superficial ring. The cause of 
this descent is not accurately known, but it is aided by the gubernaculum 
testis, a mass of unstriated muscular fibres, attached by one extremity to 
the testicle and by the other to the margins of the superficial abdominal 
ring. In its descent the testicle carries with it the structures closing the 
two abdominal rings. Thus, it presses upon the peritoneum at the deep 
abdominal ring, invaginates it and forces along a process of this mem- 
brane which becomes the deepest layer investing the testicle and is known 
as the tunica vaginalis; next it forces along a process of the transversalis 
fascia, which, after the descent of the testicle, becomes attached to the 
deep ring forming the infundibuliform tube of fascia; then, while passing 
beneath the conjoined arch, muscular fibres, arranged in loops around the 
cord, are contributed forming the cremaster muscle, which is attached 
internally to the sheath of the rectus and externally to Poupart’s 
ligament. These loops are attached to each other by fascia called the 
cremasteric fascia. Lastly, the testicle carries with it a process of the 
intercolumnar fascia, forming the external covering of the cord, which is, 
of course, covered by the superficial fascia and integument. Shortly 
after birth the tunica vaginalis is obliterated from the internal ring to 
within a short distance of the testicle. 
When, from weakening of the abdominal wall, or other cause, an ingui- 
nal hernia is produced, it usually follows the course of the testicle in its 
descent, and, hence, its coverings would be similar to those of the testicle. 
This form is known as an oblique inguinal hernia, subdivided into com- 
plete, when it escapes from the superficial abdominal ring, and incom- 
plete, or bubonocele, when it remains in the inguinal canal. A complete 
inguinal hernia pushes before it the peritoneum closing the deep abdomi- 
nal ring, which forms the hernial sac, enters the inguinal canal, receiving 
an investment from the infundibulum tube of fascia and the cremaster 
muscle, passes through the superficial abdominal ring, carrying with it a 
covering furnished by the intercolumnar fascia, descends in front of the 
cord into the scrotum and is invested by the superficial fascia and the 
integument. In incomplete hernia the coverings cease at the superficial 
abdominal ring. 
When the peritoneal pouch is not obliterated, there is a direct commu- 
nication between the abdominal and scrotal cavities, and the peritoneal 
covering of the hernia is the tunica vaginalis. This form of hernia con- 
stitutes what is known as congenital hernia. 338 
Notes on Anatomy. 
In infantile hernia the pouch is closed at the deep abdominal ring only, 
and the gut descends behind the tunica vaginalis, having three peritoneal 
layers in front, viz; the two layers of the tunica vaginalis and one layer 
of the proper investing sac of the hernia. 
In the encysted form the gut, carrying its own sac, projects into the 
tunica vaginalis, leaving in front of it but two serous layers, viz; one of 
its own sac and one from the tunica vaginalis. 
Direct Inguinal Hernia.—Hesselbach’s triangle is bounded ex- 
ternally by the deep epigastric artery, internally by the rectus abdominis, 
below by Poupart’s ligament. It is crossed by the conjoined tendon of 
internal oblique and transversalis muscles. Hernia may occur either ex- 
ternal to or through this tendon. When the hernia is external to the 
tendon it follows a part of the inguinal canal and has the same coverings 
as an oblique inguinal hernia, except that the infundibuliform tube is 
replaced by another prolongation of the transversalis fascia. When 
through the tendon the latter is pushed before the gut, which has the same 
coverings as in the oblique form, except that the infundibuliform tube is 
replaced by another portion of the transversalis fascia, and the con- 
joined tendon replaces the cremaster muscle. Occasionally the hernia 
may split the tendon instead of pushing it before it. Femoral Hernia. 
339 
FEMORAL HERNIA. 
Definition.—The protrusion of an abdominal viscus through the 
femoral or crural ring. 
Parts Concerned.—Behind the femoral arch is found the upper 
border of the pubic bone, marked, from within outward, by the angle, 
crest, spine, pectineal line, triangle and eminence and the psoas groove. 
Stretching from the anterior superior spinous process of the ilium to the 
pubic spine and pectineal line, is Poupart’s ligament, forming the femoral 
or crural arch. Gimbernat’s ligament is the portion of Poupart’s liga- 
ment which is inserted into the pectineal line. The other structures 
concerned are the iliac artery and vein and their sheath, the peritoneum 
and fascia closing the mouth of the ring, the fascia lata, cribriform and 
superficial fasciae and the integument. 
The space between Poupart’s ligament and the upper border of the 
pubes is filled from without inward by the psoas and iliacus muscles, the 
anterior crural nerve and the femoral sheath containing the femoral artery 
and vein and having in it an unoccupied space internal to the vein. This 
sheath is formed in front by the transversalis, behind by the iliac fascia. 
Femoral Ring.—The femoral ring is the upper opening of the 
femoral canal. Internally it is bounded by the outer edge of Gimber- 
nat’s ligament; externally by a septum in the sheath separating the open 
space from the femoral vein; above is Poupart’s ligament; below, the 
upper border of the pubes and the origin of the pectineus muscle. The 
femoral canal extends downward in the sheath for about one inch and is 
lined by a prolongation of fascia which covers the vessels and is known 
as the fascia propria. The canal terminates by the contraction of the 
sheath so as to closely hug the vessels. The femoral ring is closed 
above by the peritoneum and a thin layer of fascia called septum crurale, 
or femorale, which usually has lying upon it a lymphatic gland. 
Blood Vessels.—Just beneath Poupart’s ligament the external iliac 
vessels terminate by becoming the femoral; but, before its termination, 
the external iliac artery gives off a large branch called the deep epigas- 
tric, which lies above and external to the femoral ring and between it 
and the deep abdominal ring. The external iliac vein lies to the outer 340 
Notes on Anatomy. 
side of the ring, so that in all cases there are blood vessels above and 
external to the ring. The deep epigastric artery sometimes gives ofif a 
branch called the obturator, which may descend next the iliac vein and 
on the outer side of the ring; but it sometimes passes inward and down- 
ward, arching above and internal to the femoral ring, which is thus sur- 
rounded by blood vessels on all sides except below. The epigastric also 
gives off a small pubic branch which lies above the ring, but is, from its 
size, unimportant. 
Fascia Lata.—The investing fascia of the thigh, or fascia lata, pre- 
sents, about one inch below Poupart’s ligament, an oval opening called 
the saphenous opening. The opening is closed in the recent state. It 
runs obliquely downward and outward, is about one inch in its vertical 
by three-quarters of an inch in its transverse diameter; its inner edge is 
straight and prolonged outward behind the outer edge; its outer is 
curved, runs downward and outward from Gimbernat’s ligament to the 
inferior cornu and is called Key’s ligament or the falciform process of 
Burns. The external part of the fascia is known as the iliac portion and 
is attached to the crest of the ilium and the outer portion of Poupart’s 
ligament, sending inward a spur which is attached to the pectineal line, 
runs over the femoral vessels and forms the outer boundary of the saphe- 
nous opening. The inner part, called the pubic portion, is thin and 
weak, is attached to the ischio-pubic ramus and is prolonged beneath 
the femoral vessels. The saphenous opening is covered by the skin and 
two layers of superficial fascia, of which the deep, under the name of 
cribriform fascia, becomes adherent to the margins of the opening. The 
cribriform fascia is attached more firmly below than above, and hence 
tends to direct a protruding gut upward. 
Course.—A femoral hernia passes downward through the femoral 
ring, thence down the canal as far as the saphenous opening, turns for- 
ward through this opening and then runs upward on the front of the 
thigh. The main causes of the ascent are the firmer attachment of the 
cribriform fascia below, the narrowing of the femoral canal and the move- 
ments of the thigh. 
Coverings.—Femoral hernia pushes before it, first the parietal layer 
of peritoneum and fat covering the femoral ring, then the septum femo- 
rale, fascia propria, cribriform fascia, superficial layer of the superficial 
fascia and, lastly, the skin. Organs of Generation in the Female. 
341 
ORGANS OF GENERATION IN THE FEMALE. 
The organs of generation in the female are divided into those within 
and those external to the pelvic cavity. The external organs, vulva, cli- 
toris, &c., occupy the perineal space. The boundaries of the outlet of 
the pelvis are the same in both male and female subjects, but the ischio- 
rectal region is wider and longer in the female. In the mid-line are seen 
the opening of the vagina and the anus, separated by a mass of tissue 
about one inch thick called the perineal body. The external organs con- 
sist of two labia majora, surrounding the aperture of the vagina, com- 
posed externally of skin, which is covered with hairs and internally of 
mucous membrane, and united both in front and behind. Internal to 
these are two thinner projecting folds, one on each side, called labia 
minora, which enclose in front a projecting body, the clitoris. Between 
the clitoris and the mouth of the vagina is a space about one inch long 
called the vestibule, at the hinder part of which, near the mouth of the 
vagina, is an opening, the meatus urinarius. 
The pelvic organs consist of an egg-producing body—the ovary—and 
a channel to convey the egg to the exterior. This channel is modified 
to perform the function of hatching—the uterus—and that of copula- 
tion—the vagina. The uterus consists of an upper part or fundus, a 
middle portion or body, and a lower part or neck. The vagina is a 
short, bent canal which serves the double function of conveying the 
semen to the uterus and of conducting the foetus to the external world. 
The relations which the uterus and its so-called appendages bear to 
neighboring structures constitutes the remainder of the study of the 
female generative organs. 
The peritoneum passes over the brim of the pelvis, enveloping the 
first portion of the rectum completely, and covering the upper one inch 
of the second portion in front, as in the male. From the front of the 
rectum it passes to the posterior wall of the vagina, which it covers for its 
upper one inch or inch and a half; passes to the back of the uterus and 
mounts upon it to its top, where it spreads out upon either side to en- 
velop the appendages of the uterus; descends upon the front of the 
uterus, covering all of the front except that part contained within the 
vagina, and thence passes to the bladder, which is covered, as in the 
male, for its posterior half, the peritoneum leaping from the top of the 342 
Notes on Anatomy. 
bladder to the posterior surface of the anterior abdominal wall, forming 
the false ligaments of the bladder as in the male. That fold of perito- 
neum which extends transversely outward from the top of the uterus, 
envelops the appendages of that organ in a double-layered fold which 
forms a vertical septum extending transversely across the pelvic cavity, 
striking the lateral pelvic walls a little behind their middle, is known as 
the broad ligament of the uterus. The folds of peritoneum between the 
uterus and vagina and rectum posteriorly and the uterus and bladder 
anteriorly are known as the posterior and anterior ligaments of the 
uterus respectively, divided by the mid-line into two anterior and two 
posterior. Another ligament, a round cord, extends, in the folds of the 
broad ligament, from the lateral aspect of the uterus to the internal ab- 
dominal ring, to follow the inguinal canal and be finally lost in the labium 
majus, under the name of the round ligament. The depression between 
the vagina and uterus in front and the rectum behind is known as the 
pouch of Douglas, the posterior ligaments bounding it on either side. 
The broad ligament encloses between its folds the fallopian tube, liga- 
ment of the ovary, round ligament and ovary. The fallopian tubes oc- 
cupy the highest part of the broad ligament, extending outward from the 
upper angle of the uterus to become closely connected with the ovary. 
They enlarge as they pass outward and form at the extremity a trumpet- 
shaped mouth, fringed by diverging processes or fimbriae, one of which 
is attached to the ovary. The tube is tortuous through the greater part 
of its course and when stretched out is about five inches long. A little 
behind and below the fallopian tube is a small round cord, the ligament 
of the ovary, which attaches the ovary to the upper part of the side of 
the uterus. 
The ovary is about one and a half inches long, one inch wide and half 
an inch thick. One end looks toward the uterus, one end outward, one 
surface upward and forward, the other downward and backward. It is 
completely invested by peritoneum, bulging the posterior fold of the 
broad ligament and appearing not to be in contact with the anterior fold. 
It is held to the uterus by its ligament and the ova formed by it are con- 
ducted to the uterus by the fallopian tube. 
The lower end of the uterus projects into the vagina, which thus sur- 
rounds the neck of the uterus, cutting off the lower portion of that organ 
from relation with surrounding viscera. The vagina extends higher up 
on the uterus posteriorly than anteriorly. 
The rectum is about the same length as in the male, and is divided into 
three portions tor study. Its lateral and posterior relations are the same Organs of Generation in the Female. 
343 
as in the male, while the anterior relations are different. The first part 
of the rectum has in front of it the uterus, separated from it by convolutions 
of the small intestine. The upper inch of the second portion, that part 
covered by peritoneum in front, is separated, by convolutions of the 
small intestine, from the posterior wall of the vagina, which in turn cuts 
off the neck of the uterus. The remainder of the second portion is ad- 
herent to the posterior wall of the vagina. The third part of the rectum 
passes downward and backward, diverging from the vagina, the interval 
between the two being filled by a triangular mass of connective tissue 
forming the perineal body and corresponding to the tissue between the 
bulb of the corpu*s spongiosum and the rectum in the male. The ureter 
bears the same relation to the rectum as in the male, and lies upon the 
side of the vagina which cuts it off from relation with the neck of the 
uterus. 
The female bladder occupies the same position as in the male, lying 
behind the symphysis pubis and bearing the same relation to the perito- 
neum. The anterior and lateral relations are also the same, except that 
there is no vas deferens, the position of this structure being in part occu- 
pied by the round ligament, which lies above and internal to "the external 
iliac artery. The posterior surface of the bladder is separated from the 
anterior wall of the uterus by some convolutions of the small intestine. 
The base of the bladder looks more nearly downward than in the male 
and rests for its anterior three-fourths upon the anterior wall of the 
vagina, to which it is firmly adherent, its posterior one-fourth being cov- 
ered by peritoneum. The urethra is nearly straight, but has a slight up- 
ward concavity. It lies on the anterior wall of the vagina, is about two 
inches long, runs through an opening in the triangular ligament about 
one inch below the symphysis pubis, is surrounded by muscular fibres 
forming what is called the compressor urethrae, and terminates in the ves- 
tibule at the meatus urinarius. 
The vagina is the canal of communication between the uterus and the 
vulva. It is directed obliquely downward and forward, corresponding to 
the axis of the outlet of the pelvis, while the uterus corresponds to the 
axis of the brim, the two thus forming a curve whose concavity is forward. 
It is compressed, so that its anterior and posterior walls are in contact. 
Its anterior wall is about two and a half inches in length, its posterior 
about three and a half. It is partly closed in the virgin by the hymen. 
The relations of the vagina have been given in connection with other 
structures. 344 
Notes on Anatomy. 
THE AXILLA. 
The space known by this name lies between the chest wall internally, 
the humerus externally and the muscles in front and behind. In the 
skeleton only the apex of the space is complete, being bounded in front 
by the clavicle, behind by the upper border of the scapula, internally by 
the first rib. Below the apex the space corresponds to the upper five 
ribs internally, the scapula behind and the bottom of the bicipital groove 
externally. In the recent'subject the space has the shape of a three-sided 
pyramid. The apex is above, the base below and the sharp angle exter- 
nal at the bicipital groove. The whole space is closed in by soft struc- 
tures. The anterior wall is furnished by the pectoralis major, which 
covers the whole of the space, while beneath this, forming only the mid- 
dle of the anterior wall, is the pectoralis minor. The posterior wall is 
formed by three muscles, subscapularis, teres major and latissimus dorsi; 
but the order in which they come changes in different parts of the space. 
Near the inner wall the order, from above downward, is subscapularis, 
teres major, latissimus dorsi; but near the external wall, owing to the fact 
that the tendon of the latissimus dorsi winds around the teres major and 
is inserted above it, the order is subscapularis, latissimus dorsi, teres 
major. The inner wall is formed by the upper six serrations of the serra- 
tus magnus muscle and the intercostal muscles corresponding to the upper 
five intercostal spaces. The lower border of the muscles which enter into 
the anterior and posterior boundaries of the axilla form the anterior and 
posterior axillary folds, of which the posterior is the' thicker and more 
prominent. Stretching across from one fold to the other, and continuous 
with the investing fascia of the arm, is a strong fascia which forms the 
floor of the space. The contents of this space are the brachial plexus 
of nerves and its terminal branches, the axillary artery and vein and 
their branches, lymphatic glands and a quantity of areolar tissue and fat. INDEX. 
Abdomen, boundaries of, - • - - 105 
lymphatics of, - - - - 287 
muscles, - - - 184 
regions, - - - - 105 
viscera, - 117 
Abdominal aorta, ----- 225 
branches of, - - - 251 
ring, external, - 335 
“ internal, - 336 
viscera, position of, - 109 
Abducent nerve, - 298 
Abductor minimi digiti (hand), - - - 203 
“ “ (foot), - - - 218 
pollicis (hand), - - - - 203 
“ (foot), - - - - 218 
Accelerator urinae, ----- 334 
Accessorius muscle, - 219 
Acetabulum, r - - - -27 
Acromial muscle, - - - - 192 
thoracic artery, - - - - 242 
Acromio-clavicular joint, - - - 85 
Acromion process, - - - - - 17 
Al?e of vomer, ----- 51 
Alar ligaments, - - - - 93 
thoracic artery, - 242 
Alimentary canal, - - - - - 98 
Alveolar process, lower jaw, 58 
upper jaw, - - - - 55 
Anconeous muscle, - - - - 201 
Angle, jaw, - - - - 59 
pubes, - - - - - 26 
rib, - - - - 13 346 
Index 
Angular convolutions, - - - -152 
movements, - - - 77 
process, external and internal, - - 39 
Ankle joint, - - - - . - 94 
Annulus ovalis, - - - - , - 141 
Anterior ethmoidal cells, - - - - 48 
fossa skull, 63 
region skull, - - - - 65 
Antitragus, ----- 156 
Antrum of Highmore, - - - - 52 
Anus, 121 
Aorta, ------ 222 
abdominal, - 225 
branches of, - - - - 226 
arch of, - - - - - 223 
descending, ----- 225 
Aortic opening diaphragm, - - - 184 
semilunar valves, - - - - 144 
sinuses, - - - - 144 
Appendages of eye, ----- 163 
Appendix, right auricle, - - - - 141 
left auricle, - - - - 143 
vermiform, - 111 
Aqueductus vestihuli, - - - 42 
Fallopii, 43 
Sylvius, _ _ _ _ 155 
Aqueous humor, - - - - 167 
Arachnoid of brain, ----- 145 
cord, _ - . _ 304 
Arm, arteries of, - - - - - 243 
fascia, - - - - - 194 
lymphatics, ----- 288 
muscles, - - - - - 194 
nerves, - - - - - 311 
veins, - - - - - 278 
Artery, or Arteries : 
acromial thoracic, - 242 
alar thoracic, - 242 Index 
347 
Artery, or Arteries (Continued) ; 
angular, ----- 231 
anterior cerebra 1, - 273 
choroid, _ . . . 274 
ciliary, - - - - 273 
communicating’, - - - 274 
articular of knee, - 265 
axillary, ----- 240 
basilar, ----- 238 
brachial, - 243 
calcanean, - - - - - 267 
carotid, common, ... 227 
external, - 229 
internal, - - - 270 
circumflex, arm, - 242 
thigh, - 264 
colica dextra, - 254 
media, - 254 
sinistra, - 255 
coronary, heart, - 226 
lips, - 231 
digital, - - - - - 247 
epigastric, - - - - - 261 
facial, ----- 231 
femoral, - - - - - 261 
deep, _ - . - 263 
gastric, - 252 
gastro-epiploica dextra, - - - 253 
sinistra, - - - 253 
gluteal, ----- 260' 
hepatic, - - - - - 253 
ileo-colic, - - - - 254 
iliac, common, - - - - 256 
external, - 260 
internal, - - - - 267 
innominata, - - - - 227 
internal mammary, - 239 Index 
Artery, or Arteries (Continued): 
maxillary, ... 233 
plantar, - - - - 267 
intestini tennis, - 254 
lateralis nasi, - - - - 231 
lingual, ----- 230 
long thoracic, - 242 
obturator, - 258 
occipital, ----- 232 
optbalmic, - 271 
plantar, ----- 267 
perineal, - 259 
peroneal, ----- 266 
phrenic, - - - - 251 
radial, - 244, 248 
renal, - - - - - 256 
sciatic, - - - - 258 
splenic, ----- 253 
temporal, - 232 
thyroid axis, - 239 
tibial, anterior, - 268 
posterior, - 266 
transversalis colli, - 239 
ulnar, ----- 245, 247 
vertebral, - 238 
Articulations in general, - - - - 75 
Articulation, ankle, - - - - - 94 
calcaneo-astragaloid, 95 
cuboid, - - - - 96 
carpal, 90 
costo-vertebral, - - - - 82 
costo-sternal, 84 
elbow, - - - - - 88 
hip, 91 
knee, - - - - - 92 
occipito-atloid, - - - 80 
pelvis, - - - - 84 Index 
349 
Articulation, radio-carpal, - - - 89 
ulnar, - - - 87 
shoulder, 86 
sterno-clavicular, - - - 85 
temporo-maxillary, 83 
tibio-fibular, - - - - 94 
vertebral column, - - - 78 
wrist, - - - - - 89 
Arytenoid cartilage, - - - - 133 
Ascending colon, - - - - - 111 
Astragalus, ----- 34 
Atlas, - - - - - - 7 
Auditory nerve, - - - - 299 
Auricle of ear, - - - - 156 
heart, - 141 
Axilla, - - - - - - 344 
Axillary artery, ----- 240 
vein, - 280 
Axis, ------ 8 
B. 
Back, muscles of, - - - - - 175 
Base of brain, ----- 145 
skull, superior surface, - * - 63 
inferior surface, 64 
Basilic vein, - - - - - 279 
Bicipital fascia, ----- 195 
groove, - - - - - 18 
Bladder, relations in female, - 343 
male, - 115 
description of, - - - - 127 
Bone, or Bones : 
astragalus, - - - - - 34 
atlas, ----- 7 
axis, - - - - 8 
calcaneum, - 33 
carpal, - - - - - 21 350 
Index. 
Bone, or Bones [Continued): 
clavicle, - - - - - 15 
coccyx, - - - - 11 
cranial, - - - - 86 
cuboid, - - - - -84 
ethmoid, - - - - 47 
articulations of, - - 70 
femur, ----- 29 
fibula, - - - - - 82 
frontal, ----- 89 
articulations of, - 68 
humerus, - - - - 17 
hyoid, - - - - - 73 
ilium, ----- 25 
inferior maxillary, - - - - 58 
turbinated, - - - 50 
articulations of, - - 72 
innominata, 24 
ischium, - - - - - 25 
lachrymal, - - - 50 
malar, - - - - 51 
articulations of, - - - 78 
nasal, - - - - - 49 
articulations of, - - 70 
occipital, - - - - - 36 
articulations of, - - - 67 
palate, - - - - - 55 
articulations of, - - - 71 
parietal, - - - - 88 
articulations of, - - - 68 
patella, - - - - - 82 
radius, - - - - 20 
rib, - - - - - - 13 
sacrum, ----- 9 
scaphoid, - - - - - 34 
scapula, ----- 16 
sphenoid, - - - - - 44 Index, 
351 
Bone, or Bones (Continued): 
sphenoid, articulations of, - - - 69 
sternum, - - - - - 11 
superior maxillary, - - - 52 
articulations of, - - 71 
temporal, 41 
articulations of, - - - 68 
tibia, ----- 31 
ulna, - - - - 19 
vomer, ----- 51 
articulations of, - - - - 72 
Brain, ----- 144 
base of, ----- 145 
convolutions, - - - - 151 
interior, - - - - - 147 
membranes, - 144 
Bronchi, ------ 137 
C. 
Canal, auditory, - - - - 157 
Capsular ligament, hip, - - - - 91 
shoulder, 86 
Cartilage, arytenoid, - - - - 133 
cricoid, - 133 
Cava, inferior, - - - - - 277 
superior, ----- 281 
Cerebellum, ----- 154 
Cerebrum, ----- 144 
Clavicle (See Bones). 
Cceliac, axis (See Arteries). 
Coraco-acromial ligament (See Articulations), 
clavicular (See Articulations). 
Corpus callosum, ----- 145 
fimbriatum, - - - - 150 
Costal cartilages, - - - - - 14 
Cranial bones, ----- 36 
nerves, ----- 291 352 
Index 
Cranial nerves, eighth, - - - - 299 
eleventh, - 303 
filth, 294 
first, - 293 
fourth, - - - - 294 
ninth, - - - - 299 
second, - 293 
seventh, - - - - 296 
sixth, - _ . _ 296 
tenth, - 301 
third, - 294 
twelfth, - 303 
Crystalline lens, - - - - 167 
E. 
Ear, ------ 156 
Elbow, bend of, - - - - - 243 
joint, - - - - - 88 
Epididymis, ----- 131 
Epiglottis, ------ 133 
Ethmoid bone (See Bones). 
articulations of (See Bones). 
Eye, ------ 163 
tunics of, 165 
muscles of, - 169 
F. 
Face, arteries of, - - - - 231 
bones, ----- 49 
muscles, - 172 
Fauces, isthmus of, - - - 100 
Female, generative organs, - 341 
Femoral artery, - - - - 261 
canal, - - - - - 339 
hernia, - 339 
Fifth nerve (See Cronial Nerves). 
First nerve (See Cronial Nerves). Index 
353 
Fissures of brain, ----- 151 
Foot, arteries of, - 267, 269 
. bones, - - - - 33 
muscles, ----- 217 
ligaments, - - - - - 95 
nerves, ----- 323,325 
Fossa, spheno-maxillary, - - - 62 
of skull, anterior, 63 
middle and posterior, - - - 63 
temporal, ----- 61 
zygomatic, - - - - - 61 
G. 
Ganglion, cervical, - 326 
Meckel’s, - - - - 330 
otic, ----- 331 
semilunar, - - - - 328 
11. 
Hand, bones of, - - - - - 21 
ligaments, - - - 90 
Heart, - 140 
Hernia, femoral, - 339 
inguinal, - - - 335 
Hip joint, - - - - - 91 
I. 
Ileum, - 110 
Iliac arteries, common (See Arteries). 
external, “ 
internal, “ 
veins, external (See Veins). 
internal, “ 
Ilium (See Bones). 
Inferior vena cava, - - - - - 277 354 
Index 
Inguinal canal, - - - - 336 
hernia, - 335 
Intestine, large, - - - - 111 
small, ----- HO 
Iris, ------ 166 
Ischio-rectal region, ----- 332 
Ischium (See Bones). 
Island of Eeil (See Brain). 
Kidney, relations of, - - - - 114 
structure of, - 125 
Knee joint, ----- 92 
K. 
L. 
Larynx, cartilages of, - 132 
ligaments of, - , - - 133 
muscles of, .... 183 
Ligaments : 
acromio-clavicular, - - - 85 
ankle, - - - - - 94 
atlonto-axoid, - - - - 79 
calcaneo-astragaloid, - - - 95 
“ cuboid, 96 
“ scaphoid, - - - - 96 
common vertebral, - - - 78 
costo-vertebral, - - - - 82 
of elbow, 88 
of hip, - - - - 91 
of jaw, 83 
of knee, - - - - - 92 
radio-carpal, 89 
radio-ulnar, - - - -87 
sacro-sciatic, 84 
of shoulder, - - - 86 
tibio-fibular, 94 
Liver, relations of, - - - - 114 
structure of, - - - - 121 
Lungs, relations of, - - - - - 137 
structure of, - - - - 137 Index 
355 
Lymphatics : 
arm, ----- 288 
cervical, - - - - 289 
lower extremity, - - - - 288 
M. 
Malar bone, articulation of (See Bones). 
Manubrium (See Sternum). 
Mediastinum, - - - - - 189 
Medulla oblongata, - 146 
Membranes of brain, - - - 144 
cord, - 304 
Munro, foramen of (See Brain). 
Mouth, - - - - - 98 
Muscle, or Muscles : 
abductor minimi digit! (hand), ... 208 
(foot), - - 218 
pollicis (hand), - 203 
hallucis, - - - 218 
accessorius, .... 219 
adductor brevis, - 212 
longus, - - - 212 
magnus, - - - 212 
anconeus, - - - - - 201 
arytsenoideus, - - - - 183 
biceps (arm), - - - - 195 
(thigh), - - - 207 
brachialis anticus, - - - - 195 
buccinator, - - - 174 
compressor nasi, - 174 
constrictor pharyngeus, inferior, - - 102 
medius, - - 103 
superior, - - 103 
coraco-brachialis, - - - - 195 
crico-arytoenoideus lateralis, - - 183 
posticus, - 183 
crico-thyroid, - - - - 183 356 
Index, 
Muscle, or Muscles {Continued) : 
deltoid, 192 
diaphragm, - 188 
digastric, ----- 180 
extensor carpi radialis brevior, - - 200 
longior, - 200 
ulnaris, - - - 201 
communis digitornm, - 200 
indicis, - 201 
longns digitornm, - - - 216 
minimi digiti, - - - 201 
ossis metacarpi pollicis, - - 201 
primi internodii pollicis, - - 201 
proprius pollicis, - - - 216 
of face, ... - 172 
flexor brevis minimi digiti, (hand), - - 204 
(foot), - - 220 
digitornm, - 218 
pollicis (hand), - - 208 
(foot), - - - 219 
flexor carpi radialis, - - - 198 
nlnaris, - 198 
longns digitornm, - - - 215 
pollicis (hand), - - - 199 
(foot), - - 214 
ossis metacarpi pollicis, - 203 
profundus digitornm, - - 198 
sublimis digitornm, - - - 198 
gastrocnemius, - - - 218 
gemellus, superior, - 206 
inferior, - 206 
genio-hyo-glossns, - - - - 181 
genio-hyoid, - 181 
glutens maxim us, - 205 
medius, - 205 
minimus, - 206 
gracilis, - 210 Index 
357 
Muscle, oh Muscles {Continued): 
of hand, ----- 202 
of hip, ----- 204 
iliacus, ----- 211 
infraspinatus, - - - - 193 
intercostal, ----- 177 
of larynx, - - - - 183 
latissimus dorsi, - - - - 176 
levator an gull scapulae, - - - 176 
masseter, - - - - - 174 
mylo-hyoid, - - - - 180 
of neck, ----- 178 
obliquus abdominus externus, - - 184 
internus, - - - 185 
obturator externus, - 207 
internus, - 206 
omo-hyoid, - - - - 179 
of palate, ----- 100 
pectineus, - 212 
pectoralis major, - 190 
minor, - - - 191 
of perineum, - - - - 234 
peroneus brevis, - 216 
longus, - - - 217 
plantaris, - - - - 214 
platysma myoides, - - - - 178 
popliteus, . . . _ 214 
pronator quadratus, - - - - 199 
radii teres, - 197 
psoas magnus, - - - - 210 
pterygoid, external, - - - 175 
internal, - - - - 175 
pyramidalis abdominis, - - - 188 
pyriformis, ----- 205 
quadratus femoris, - - - 206 
lurnborum, - - - 190 358 
Index. 
Muscle, or Muscles (Continued): 
rectus abdominis, ... 187 
femoris, - 210 
rhomboid, - - - - 179 
sartorius, ----- 209 
scalenus anticus, - - - 182 
posticus, . _ - . 182 
semimembranosus, - - - 208 
semitendinosus, - - - - 208 
serratus magnus, - - - 192 
posticus, inferior, - - - 176 
superior, - - 177 
soleus, - - - - 218 
splenius, - - - - 177 
sterno-cleido-mastoid, - - - 178 
ster no-hyoid, - - - - 179 
sterno-thyroid, - - - - 179 
stylo-hyoid, - 180 
stylo-pharyngeus, - - - - 103 
subclavius, - 191 
subscapularis, - 193 
supinator brevis, - - - 200 
longus, - 199 
supraspinatus, - - - - 193 
temporal, - - - - - 174 
teres major, - 194 
minor, ----- 194 
thyro-arytsenoideus, - - - 184 
thyro-hyoid, - - - - 179 
tibialis anticus, - 215 
posticus, - 215 
trails'versalis abdominis, - - - 186 
trapezius, - - - - - 175 
triceps extensor cubiti, - - - 196 
cruris, - - - 211 
vastus externus, - - - - 211 
interims, - - - - 211 Index 
359 
N. 
Nares, anterior, - - - - 67 
posterior, - - - - - 67 
Nasal bones, ----- 49 
articulations of, - - - - 70 
nerve, - 295 
Neck, muscles of, - - - - - 178 
triangles of, - - - - 181 
veins of, - - - - - 282 
.Nerves, or Nerve : 
anterior crural, - - - 318 
auditory, - - - - 299 
auricularis magnus, - - - 308 
chorda tympani, - 298 
ciliary, - 330 
circumflex, - 314 
cranial, - - - - 291 
dental, anterior, - 296 
inferior, - 297 
posterior, - - - - 296 
descendens noni, - - - 303 
eighth pair, - - - - 299 
eleventh pair, - - - 303 
facial, ----- 298 
fifth, - - - - 294 
fourth, - 294 
frontal, - - - - 295 
genito-crural, - - - - 317 
glosso-pharyngeal, - - - 299 
gluteal, superior, - - - - 320 
great petrosal, - - - 330 
gustatory, - - - - 297 
hypoglassal, - - - 303 
ilio-hypogastric, ... - 316 
ilio-inguinal, - - - 317 
inferior maxillary, - 297 360 
Index 
Serves, or Nerve (Continued): 
intercostal, - - - - 315 
iiitercosto-humeral, - - - 312 
lachrymal, - 295 
laryngeal, recurrent, - - - 302 
superior, - - - 301 
long saphenous, - 318 
thoracic, - - . 311 
lumbar, - 316 
maxillary, inferior, - - 297 
superior, - - - 296 
median, - - - - 312 
muse nlo-cutaneous (arm), - 311 
(leg), - - 324 
musculo-spiral, - - 313 
ninth, - 299 
obturator, - - - 317 
occipital, small, - 308 
olfactory, - 293 
opthalmic, - - - - 295 
optic, - 293 
orbital, - - - - 296 
perineal, - 320 
peroneal, - - - - 324 
phrenic, . - - - - 309 
plantar, external, - - - 323 
internal - 323 
pneumogastric, - - - 301 
popliteal, external, - 323 
internal, - - - 322 
pudic, - 320 
radial, - 314 
recurrent laryngeal, ... 302 
■sacral plexus, - - - 319 
saphaneous, long, - 318 
short, - 322 
sciatic, great, - 321 Index, 
361 
Serves, or ISTerye {Continued)-. 
sciatic, small, - - - 321 
sixth, - 298 
spinal, accessory, - 303 
splanchnic, great, - - 328 
small, - - 328 
subscapular, - - - 311 
superficialis colli, - - 308 
suprascapular, - - - 310 
sympathetic, - - - 325 
tenth, - - - - 301 
third, - - - 294 
thoracic, anterior, - - - 310 
posterior, - - 310 
tibial, anterior, - 324 
posterior, - 322 
twelfth, - . . . 303 
ulnar, - - - - 313 
vagus, - - - - 301 
0. 
Obturator artery, - - - - 258 
relations of, to femoral ring, - 339 
externus muscles (See Muscles). 
internus “ “ 
Occipital artery (See Arteries). 
bone (See Bones). 
fossaee (See Skull). 
O. 
Occipito-atlantal articulation (See Ligaments) : 
Occipito-axial (See Ligaments): 
Oesophagus, - 103 
Omentum, great, - 108 
less, ----- 108 
Orbit, ------ 66 362 
Index 
Orbit, arteries of, - - - - - 271 
muscles of, 170 
Os calcis (See Bones). 
innominatum (See Bones). 
Ovary, - - - - - 342 
P. 
Palate bone (See Bones). 
articulations of (See Bones). 
hard (See Bones). 
muscles of, - - - - 100 
Palmar arch, deep, ----- 250 
superficial, - 245 
Pancreas, relations of, - - - - 114 
structure of, - 124 
Parietal bones (See Bones). 
articulations of (See Bones). 
eminence (See Bones). 
Patella (See Bones). 
Pelvis (See Bones). 
Penis, ------ 130 
Perineum, - 333 
Peritoneum, - 107 
Pharynx, - - - - - 101 
Pleura, ------ 133 
Pouch of Douglas, - - - 342 
R. 
Radial artery, - - - - 244,248 
nerve, - - - - - 314 
Radius (See Bones). 
articulations of (See Bones). 
Rectum, relations of, female, - - - 342 
male, - 112 
structure of, - - - - 121 
Renal artery, - 256 
Retina, _____ 160 Index 
363 
Ribs (See Bones). 
Ring, abdominal external, - 335 
internal, - 336 
crural, or femoral, - 339 
S. 
Sacral arteries, ----- 252 
foramina, - - - - -9 
plexus, - - - - -319 
Sacrum, - - - - - 9 
Scalene muscles, - 18- 
Scapula, - - - - - - 16 
Scarpa’s triangle, - 213 
Sciatic artery, - - - - 258 
..nerve, great, - 321 
lesser, ----- 321 
Shoulder joint, ----- 86 
Skull, anterior region, - - - - 65 
base of lower surface, 64 
upper surface, - - - - 63 
lateral region, - - 61 
vertex, - - - - - 60 
Soft palate, ----- 100 
Spermatic artery, ----- 256 
canal, - 836 
Sphenoid bone (See Bones). 
articulations of (See Bones). 
Sphenoidal fissure (See Bones). 
Spinal cord, - - - - - 304 
nerves, - - - - - 307 
Spine in general, - - - - - 11 
Splanchnic nerves, - 328 
Spleen, relations of, - - - - - 113 
structure of, - - - - 125 
sternum, - - - - - 11 
Stomach, relations of, - - - 109 
structure of, - - - -117 364 
Index 
Subclavian artery, left, - 250 
right, .... 234 
Sulci of brain (See Brain). 
Superior maxillary bone (See Bones). 
articulations of (See Bones). 
Sympathetic nerves, .... 325 
T. 
Tarsus, bones of, - - - - 33 
ligaments of, - - - - 95 
Temporal bone, - - - - - 41 
articulations of, 68 
Ternporo-maxi 1 lary articulation, - - - 83 
Testes, - 131 
Thalami optici (See Brain). 
Thyro-hyoid membrane, .... 134 
Thyroid cartilage, .... 133 
Tibia, - - - - - - 31 
Tongue, - - - - 98 
Trachea, --.... 135 
Trapezium bone (See Bones). 
Trapezoid “ “ 
Triangle of Hesselbach, - 337 
Scarpa’s, - - - - - 213 
Trochanter, greater (See Femur). 
lesser “ 
Turbinated bone, inferior (See Bones). 
middle, “ 
superior, “ 
articulations of, “ 
Tympanum (See Ear). 
U. 
Ulna, ------ 19 
Ulnar artery, - 245 
nerve, - - - - 313 
Ureter, - - - - - - 127 Index 
365 
Urethra, female, - - - - 343 
male, ----- 128 
Uterus, ----- 341 
Ah 
Vagina, ------ 843 
Valves ot heart, - - - 141 
Valvulse conniventes, - 120 
Ams deferens, - - - - - 129 
Veins, or Vein : 
axillary, ----- 280 
azygos, - - - - 281 
basilic, - - - - - 279 
cardiac, ----- 286 
cava, inferior, - - - - 277 
superior, - - - - 281 
cephalic, - - - - - 280 
cerebral, - - - 283 
deep or comites, - - - - 275 
femoral, - - - - - 276 
of Galen, - - - - - 283 
iliac, common, - - - - 277 
external, - - - - 276 
internal, - - - - 277 
inferior cava, - - - - 277 
innominata, left, - - - - 281 
right, _ - - - 280 
jugular, anterior, - 283 
external, - - - - 282 
internal, - - - - 282 
popliteal, - - - - - 275 
portal, - - - - - 278 
saphenous, long, - - - - 276 
short, - - - - 276 
spermatic, - - - - - 278 
subclavian, - - - - 280 366 
Index. 
Veins, or Vein (Continued): 
ulnar, anterior, - - - - 279 
common, - - - - 279 
posterior, - - - - 279 
Velum interpositum, - 150 
Ventricle of brain, third, .... 150 
fourth, - - - 151 
lateral, - 118 
Vertebrae, cervical, 5 
dorsal, - - - - - 5 
lumbar, 6 
peculiar, - - - - 7 
sacral, 9 
Vesiculae seminales, ----- 129 
Vocal cords, true, - 185 
false, ----- 185 
Vomer, ----- 51 
articulations of, - - - 72 
W. 
Willis, circle of, - - - - 271 
Winslow, foramen of, - 108 
Wrisberg, nerve of, - - - 812 
Wrist joint, - - - - - 89 
Z. 
Zinn, ligament of, 170 
Zygoma, - - - - - - 11 
Zygomatic fossa, - - - - 61 
muscles, - - - - - 172