Difference between revisions of "Talk:Book - Buchanan's Manual of Anatomy including Embryology 11"

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ranches.— (i) Grey rami communicantes, which spring from the  
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 +
 
 +
 
 +
 
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 +
 
 +
 
 +
 
 +
 
 +
CHAPTER XI
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
MALE PERINEUM.
 +
 
 +
 +
 
 +
Landmarks. —The ischial tuberosity can be felt on either side, as we
 +
as the ischio-pubic ramus; but the sacro-tuberous ligament cannot b
 +
felt, on account of the thickness of the lower border of the glutei]
 +
maximus. The posterior margin of the pubic symphysis and th
 +
tip of the coccyx are both to be felt, the former, however, only on dee
 +
pressure.
 +
 
 +
The perineum practically corresponds with the outlet of the pelvi*
 +
and is somewhat lozenge-shaped, having the subpubic angle in from
 +
 
 +
the tip of the coccy
 +
behind, and the ischk
 +
tuberosity on eithe
 +
side. It is convenient!
 +
divided into two part
 +
by a line connectin
 +
the ischial tuberosities
 +
each division being tri
 +
angular. The anterio
 +
constitutes the urc
 +
genital division, thi
 +
being the perineur
 +
proper, and the pos
 +
terior the anal divisior
 +
The skin of the uro
 +
genital division present
 +
an antero-posterior me
 +
dian elevation, calle<
 +
the perineal raphe
 +
which extends over th'
 +
posterior and anterior surfaces of the scrotum, and along the unde
 +
surface of the penis, indicating the bilateral origin of these parts
 +
The position of the deeply-placed perineal body is indicated by taking
 +
a point in this raphe about an inch in front of the anus.
 +
 
 +
The anus is the external opening of the anal canal. It is situatec
 +
posterior to a line connecting the front parts of the ischial tuberosities
 +
and about inches from the tip of the coccyx. A delicate white lin<
 +
surrounds the anus where the skin and mucous membrane meet; i
 +
indicates the interval between the external and internal sphinctei
 +
 
 +
674
 +
 
 +
 
 +
 
 +
Fig. 404.—Lower Aperture of Male Pelvis.
 +
 
 +
SP, subpubic ligament; ST, sacro-tuberous
 +
ligament; T, tuber ischii.
 +
 
 +
 
 +
 
 +
THE ABDOMEN 675
 +
 
 +
tuscles (Hilton). The position of each ischio-rectal fossa is indicated
 +
y a slight depression between the anus and ischial tuberosity.
 +
 
 +
Deep Boundaries of the Perineum— Anterior. — The subpubic angle
 +
id the inferior pubic ligament. Posterior. —The coccyx. Lateral .—
 +
rom behind forwards, the inferior border of the sacro-tuberous ligalent, the ischial tuberosity, and the ischio-pubic ramus.
 +
 
 +
 
 +
Ischio-rectal Division.
 +
 
 +
Cutaneous Nerves. —These are (1) the perineal branch from the
 +
iwer part of the anterior primary division of the fourth sacral, and
 +
:) the inferior hsemorrhoidal nerve, a branch of the pudendal. The
 +
>rmer supplies the skin between the tip of the coccyx and the anus,
 +
le latter the skin around the anus as far out as the ischial tuberosity.
 +
 
 +
Fascia. —The superficial fascia of this division is rich in fat, and is
 +
rolonged into the ischio-rectal fossa, where it forms an elastic pad on
 +
hich the pelvic floor rests.
 +
 
 +
Ano-coccygeal Body. —This is a collection of fibrous and muscular
 +
ssue situated between the coccyx and anal canal, the muscular
 +
ement being contributed by the levatores ani and sphincter ani
 +
luscles. Its importance lies in the fact that it gives support to the
 +
nal canal.
 +
 
 +
Muscles. —The muscles in this division are the corrugator cutis ani,
 +
dhncter ani externus, levator ani, and coccygeus.
 +
 
 +
Corrugator Cutis Ani (Ellis). —This muscle is represented by a very
 +
elicate sheet of involuntary muscular fibres, which pass in a radiating
 +
tanner from the submucous tissue of the anal aperture to be inserted
 +
tto the surrounding skin.
 +
 
 +
Action. —(1) To throw the skin around the anus into wrinkles; and
 +
’) to invert the mucous membrane of the lower end of the anal canal
 +
her it has been everted during defsecation.
 +
 
 +
For the levator ani and coccygeus, see pp. 947 and 948.
 +
 
 +
Sphincter Ani Externus — Origin. —The tip of the coccyx and the
 +
bn over it.
 +
 
 +
Insertion .—The greater part of the muscle is inserted into the
 +
erineal body. The more superficial fibres, however, are inserted
 +
ho the skin, and a certain amount of decussation takes place across
 +
ie middle line.
 +
 
 +
N erve-supply .—The part of the muscle between the coccyx and
 +
ie anus is supplied by the perineal branch of the fourth sacral, the
 +
^mainder by the inferior hsemorrhoidal and the muscular branch of the
 +
erineal nerve, both of which are derived from the pudendal.
 +
 
 +
Action .—To keep the anal aperture closed, at the same time proving a wrinkled condition of the skin.
 +
 
 +
The muscle is situated immediately beneath the skin, and is
 +
liptical. Behind and in front of the anus it is single, but around
 +
iat aperture it is arranged in two symmetrical halves, which are
 +
itimately connected with the middle portions of the levatores ani.
 +
 
 +
 
 +
676
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
Ischio-rectai Fossa. —This is a deep fossa which is situated 0
 +
either side between the ischium and rectum. It measures near!
 +
2J inches in depth, 2 inches from before backwards, and 1 inch froi
 +
side to side. In transverse section it is triangular, the base bein
 +
directed downwards and the apex upwards. The outer wall, which
 +
vertical, is formed by the lower part of the obturator internus muse
 +
covered by the obturator fascia. The inner wall, which is oblique,
 +
formed by the lower part of the rectum, the anal canal, the levatc
 +
ani muscle covered by the anal fascia, and the sphincter ani externu
 +
The base is formed by the skin and fascia, which extend between th
 +
 
 +
 
 +
Scrotum
 +
 
 +
 
 +
 
 +
Deep Layer of Superficial
 +
Perineal Fascia (right half)
 +
 
 +
 
 +
Superficial Perineal Nerves
 +
 
 +
Long Perineal Nerve
 +
 
 +
Superficial Transverse
 +
Perineal Muscle
 +
 
 +
 
 +
Inferior Haemorrhoidal Nerve
 +
 
 +
 
 +
Gluteal Cutaneous Branches
 +
of Posterior Cutaneous Nerve
 +
of Thigh
 +
 
 +
 
 +
Perforating Cutaneous Nerve
 +
 
 +
 
 +
Perineal Body
 +
Superficial Perineal Artery
 +
 
 +
Transverse Perineal Artery
 +
 
 +
Internal Pudendal Artery i
 +
the Pudendal Canal
 +
Inferior Rectal Artery
 +
 
 +
Gluteal Cutaneous Branch!
 +
of Inferior Gluteal Artery
 +
 
 +
 
 +
Perineal Branch of 4th Sacral Nerve
 +
 
 +
 
 +
Fig. 405. —Dissection of the Male Perineum.
 +
 
 +
On the left side the bulbo-spongiosus has been removed and the crus
 +
 
 +
penis cut.
 +
 
 +
ischial tuberosity and anus. The roof is just below the white line
 +
where the anal fascia springs from the obturator fascia. Anteriorly
 +
the fossa is partially limited by the deep layer of superficial perinea
 +
fascia as it is reflected round the posterior border of the superficia
 +
transverse perineal muscle on its way to join the base of the perinea
 +
membrane. Above this junction there is a forward prolongation o
 +
the fossa, called the anterior diverticulum , which extends almost U
 +
the symphysis pubis; it lies between the superior layer of the perinea
 +
membrane and the inferior surface of the anterior part of the levatoi
 +
ani muscle, and is limited by the prostate gland and pubo-prostati<
 +
ligament medially, and by the ischio-pubic ramus laterally. Posteriori
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
677
 +
 
 +
 
 +
he fossa is partially limited by the margin of the sacro-tuberous
 +
igament and the lower border of the gluteus maximus muscle. Beween these two structures it is prolonged backwards for a short
 +
[istance in the form of a posterior diverticulum, which extends outwards
 +
owards the ischial tuberosity, and inwards towards the upper part
 +
if the coccyx.
 +
 
 +
Position of Contents. —The internal pudendal vessels and the
 +
>erineal and dorsal nerve of penis, branches of the pudendal nerve, lie
 +
n the pudendal canal, which runs along the outer wall 1J inches above
 +
he lower part of the ischial tuberosity. The inferior rectal vessels
 +
,nd nerve cross the fossa transversely from the outer wall to the anal
 +
;anal. The perineal vessels and nerves, branches respectively of the
 +
nternal pudendal vessels and of the perineal branch of the pudendal
 +
lerve, lie for a short distance, as they run forwards, in the front part
 +
>f the fossa, where they anastomose and form connections with branches
 +
)f the inferior rectal vessels and the inferior haemorrhoidal nerve. At
 +
he back part of the fossa, winding round the lower border of the gluteus
 +
naximus, the gluteal cutaneous branches of the posterior cutaneous
 +
lerve of thigh and the inferior gluteal artery, as well as the perforating
 +
;utaneous branch from the sacral plexus, are to be seen.
 +
 
 +
The fossa is filled with loose fat, which also extends into the anterior
 +
ind posterior diverticula.
 +
 
 +
This fat is badly supplied with bloodvessels, and its vitality is therefore low.
 +
\.s a consequence, an ischiorectal abscess is of not infrequent occurrence. When
 +
m abscess forms, the pus has a tendency to discharge itself in two directions—
 +
lamely, through the skin forming the floor of the fossa, and through the wall of
 +
;he anal canal about inch above the anus. If the discharge is effected in either
 +
)r both of these two ways a fistulo in ano is the result.
 +
 
 +
The severe pain which accompanies an ischio-rectal abscess is due to pressure
 +
lpon the following nerves: (1) the inferior haemorrhoidal; (2) the two superficial
 +
lerineal nerves; and (3) the gluteal cutaneous branches of the posterior cutaneous
 +
lerve of thigh.
 +
 
 +
 
 +
Uro-genital Division.
 +
 
 +
Superficial Fascia. —The superficial fascia resembles that over the
 +
ower part of the anterior wall of the abdomen in being divisible into
 +
:wo layers, which are called the superficial layer and the deep layer.
 +
 
 +
The superficial layer contains a granular variety of fat which is
 +
n sharp contrast with the lobulated fat of the ischio-rectal division.
 +
When followed backwards it forms on either side the floor of the
 +
Lschio-rectal fossa. At the middle line it is continuous with the corresponding layer of the, opposite side. Laterally it passes freely over
 +
the ischio-pubic ramus, and is continuous with the superficial fascia
 +
of the inner side of the thigh. Anteriorly it passes into the scrotum,
 +
where it joins the deep layer. The resultant fascia, now free from
 +
adipose tissue, contains involuntary muscular tissue, and forms the
 +
iartos muscle. The superficial layer represents the superficial fascia
 +
of the anterior abdominal wall.
 +
 
 +
The deep layer (Fascia of Colles) is membranous and strong.
 +
 
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
678
 +
 
 +
Laterally it is attached to the anterior everted lip of the inner horde
 +
of the ischio-pubic ramus as far back as the ischial tuberosity, in
 +
mediately outside the attachment of the crus penis. Medially tt
 +
fascia of one side is continuous with that of the other at the middl
 +
line. Posteriorly the fascia turns round the posterior border of eac
 +
superficial transverse perineal muscle, and joins the base of the perine;
 +
membrane. Anteriorly it passes into the scrotum, where it joins tt
 +
superficial layer, the two forming the dartos muscle.
 +
 
 +
The deep layer of superficial perineal fascia represents the dee
 +
fascia of the anterior abdominal wall. It forms in the erect positic
 +
the floor of a space called the perineal pouch. This pouch is partial]
 +
subdivided into two compartments by an incomplete septum, whic
 +
extends upwards from the deep or superior surface of the deep lay(
 +
of superficial perineal fascia to be attached to the overlying perine;
 +
membrane. This septum is only complete at the back; elsewhere
 +
is very imperfect.
 +
 
 +
When air is blown beneath the back part of the deep layer of supei
 +
ficial perineal fascia on one side of the middle line, the perineal pouc
 +
of that side and the corresponding half of the scrotum become di;
 +
tended. As more air is blown in, the pouch of the opposite side an
 +
the corresponding half of the scrotum also become distended.
 +
 
 +
It is into the perineal pouch that urine is extravasated in rupture of the urethi
 +
in the perineum. In such cases the urine cannot pass into either ischio-rect;
 +
fossa, its backward course being arrested at the posterior borders of the superfici;
 +
transverse perineal muscles, where the deep layer of superficial perineal fascia, £
 +
a whole, turns round to join the base of the perineal membrane. Neither ca:
 +
the urine make its way down the inner side of the thigh, its passage in th:
 +
direction being stopped at the ischio-pubic ramus, to which the deep layer c
 +
superficial perineal fascia is attached. The only course, therefore, which is ope
 +
to the extravasated urine is forwards into the scrotal wall and on to the peni
 +
in each case beneath the dartos muscle, whence it passes upwards along th
 +
spermatic cord to the anterior wall of the abdomen, in which situation it lie
 +
beneath the deep fascia.
 +
 
 +
The deep layer of superficial perineal fascia covers the followin
 +
structures: the crura penis, covered by the ischio-cavernosus muscles
 +
the bulb of the penis, covered by the bulbo-spongiosus muscles; th
 +
superficial transverse perineal muscles; the superficial perineal vessel
 +
of each side; the two superficial perineal nerves and the long perinea
 +
nerve; the terminal branches of the deep division of the perineal branc
 +
of the pudendal nerve to the superficial perineal muscles, the bull
 +
and urethra; the terminal branches of the dorsal penis branch of th
 +
pudendal nerve to the corpus cavernosum and penis; and the inferio
 +
layer of the perineal membrane.
 +
 
 +
Muscles—Transversus Perinaei Superficial^ (Fig. 406)— Origin.The ramus of the ischium superficial or deep to the ischio-cavernosus.
 +
 
 +
Insertion .—The perineal body.
 +
 
 +
Nerve-supply .—The deep division of the perineal branch of th
 +
pudendal nerve.
 +
 
 +
 
 +
THE ABDOMEN 679
 +
 
 +
Action .—To draw back and fix the perineal body, and so to aid
 +
he action of the bulbo-spongiosus.
 +
 
 +
The muscle is directed obliquely inwards and forwards, being
 +
ccompanied by the transverse perineal artery, and being crossed
 +
uperficially or deeply by the superficial perineal nerves. It forms
 +
he base of a triangle, the other two sides being formed by the bulbopongiosus and ischio-cavernosus muscles.
 +
 
 +
Ischio-cavernosus (Erector Penis) — Origin. —(1) The inner aspect
 +
f the ischial tuberosity; and (2) the inner border of the ramus of the
 +
schium on either side of the crus penis.
 +
 
 +
 
 +
 
 +
Bulbo. Sp.
 +
Isch. Cav.
 +
 
 +
 
 +
Perin. Memb. (inf.).
 +
Sup. Trans. P.
 +
 
 +
 
 +
Lev. Ani
 +
Ext. Sph. Ani
 +
 
 +
Gluteus Max.
 +
 
 +
 
 +
Fig. 406. —Superficial Dissection to show Perineal Muscles and
 +
 
 +
ISCHIO-RECTAL FOSSA.
 +
 
 +
 
 +
Insertion .—The under surface of the fibrous sheath of the crus
 +
Denis in its front part, and the outer and upper surfaces of the fibrous
 +
sheath of the corpus cavernosum penis, in which latter situation it is
 +
continuous with the fascial investment of the penis and with the
 +
suspensory ligament of that organ.
 +
 
 +
Nerve-supply .—The deep division of the perineal branch of the
 +
pudendal nerve.
 +
 
 +
Action .—The muscle compresses the crus penis against the ischiopubic ramus, and, by retarding the return of venous blood, it helps
 +
to maintain the penis in a state of erection. It also contributes to the
 +
maintenance of erection by compressing the dorsal vein of the penis.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
68o
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
The anterior and outer part of the muscle is sometimes detached, and forn
 +
a separate muscle, called the compressor venae dorsalis penis. This arises froi
 +
the descending ramus of the- pubis, and terminates in an aponeurotic expansio
 +
which joins its fellow of the opposite side over the dorsal vein of the penis.
 +
 
 +
Bulbo-spongiosus (Fig. 406) (Accelerator or Ejaculator Urinse)
 +
Origin. —(1) The perineal body; and (2) the median raphe, which j
 +
continued forwards from that point towards the symphysis pubis.
 +
 
 +
Insertion .—The muscle, as regards its insertion, is convenientl
 +
divided into three parts—namely, the chief part, the anterior par
 +
and the posterior part.
 +
 
 +
Chief Part. —The fibres of this part ascend between the crus pen:
 +
and the side of the bulb, to be inserted into the medi'an raphe on tb
 +
upper surface of the bulb, where they meet the fibres of the corn
 +
sponding part of the opposite muscle.
 +
 
 +
Anterior Part. —The fibres of this part as they pass forward diverg
 +
in the form of a V and are inserted partly into the outer surface of tb
 +
fibrous sheath of the corpus cavernosum penis in front of the ischic
 +
cavernosus, and partly by means of a tendinous expansion into tb
 +
fascial investment of the penis, beneath which the dorsal vein of th
 +
penis lies; they are sometimes regarded as forming a separate musclethe constrictor radicis penis.
 +
 
 +
Posterior Part. —The fibres of this, which is also the deepest pari
 +
surround like a close-fitting cap the hemispheres of the bulb, and ar
 +
inserted into the dorsal surface of the bulb immediately in front c
 +
the point of entry of the urethra.
 +
 
 +
TV erve-supply .—The deep division of the perineal branch of th
 +
pudendal nerve.
 +
 
 +
Action. —(1) The chief part of the muscle, acting with its fellow
 +
compresses the bulb. These portions of the two muscles therefor
 +
come into play at the end of micturition, when they expel the las
 +
drops of urine from this part of the urethra. A further action is t
 +
contribute to the maintenance of erection of the penis by compressin
 +
the veins of the bulb. (2) The anterior part compresses the dorse
 +
vein of the penis, and so contributes to the maintenance of erectior
 +
(3) The posterior part, when in action, will compress not merely th
 +
hemispheres of the bulb and their bloodvessels, but also the urethr
 +
and the ducts of the bulbo-urethral glands.
 +
 
 +
The chief portions of the bulbo-spongiosus muscles complete!
 +
surround the bulb, and may be regarded as forming a sphincter muscle
 +
 
 +
Sphincter (Compressor) Urethrae— Origin. —From the inner boreie
 +
of the inferior ramus of the pubis, lying behind or above the inferio
 +
layer of the perineal membrane.
 +
 
 +
Insertion. —Near the middle line the muscle divides into two layers
 +
which, passing above and below the membranous part of the urethra
 +
are inserted into median raphes, thus constituting a sphincter muscle
 +
The lower layer, which is by far the better developed, ensheathe
 +
also the bulbo-urethral glands. The posterior fibres of the muscle
 +
which lie close to the base of the perineal membrane, are sometime
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
681
 +
 
 +
-egarded as a separate muscle—the deep transverse muscle of the
 +
perineum.
 +
 
 +
Nerve-supply .—The dorsal nerve of the penis.
 +
 
 +
Action. —(i) To constrict the membranous part of the urethra,
 +
rhe muscle comes into play at the end of micturition, and assists the
 +
Dulbo-spongiosus in emptying the urethral canal. (2) To contribute
 +
:o the maintenance of erection of the penis by compressing the veins
 +
: rom the corpora cavernosa and bulb. (3) To compress the bulborrethral glands, and so aid in the expulsion of their secretion.
 +
 
 +
 
 +
 
 +
Fig. 407. —Deep Dissection of the Male Perineum.
 +
The rectum has been turned back.
 +
 
 +
 
 +
The sphincter urethrae muscle lies between the two layers of the
 +
perineal membrane. Close to its attachment to the ischio-pubic ramus
 +
-t contains within its substance the internal pudendal vessels and the
 +
iorsal nerve of the penis.
 +
 
 +
Perineal Body (Central Tendinous Point). —Nearly 1 inch in front of
 +
the anus there is a short transverse tendinous septum about J inch
 +
tong. At its centre it presents a thickening, to which the name of
 +
berineal body is given. The muscles which meet at this point are as
 +
follows: (1) the sphincter ani externus, coming from behind; (2) the
 +
bulbo-spongiosus, coming from before; (3) the superficial transverse
 +
perineal muscles, coming from either side; and (4) the levatores ani,
 +
coming from above. The pointed process at the centre of the base
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
682
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
of the inferior layer of the perineal membrane is also attached to the
 +
perineal body.
 +
 
 +
Bulb of the Penis. —This is the first part of the corpus spongiosun
 +
penis, and is so named from its presenting a bulbous enlargement. Ii
 +
measures about if inches in length, and about § inch in breadth ai
 +
its posterior part. Its posterior extremity rests upon the inferioi
 +
layer of the perineal membrane, and extends as far back as the perinea
 +
body, where it lies nearly i inch in front of the anus. This par
 +
extends fully J inch farther back than the bulbous part of the urethra
 +
It here presents on its under surface, in the middle line, a faint groov(
 +
indicative of its having been formed by the union of two symmetrica
 +
parts. The bulb is invested by a fibrous sheath derived from th(
 +
circumference of the urethral opening in the inferior layer of the perinea
 +
membrane, superficial to which lie fibres of the bulbo-spongiosu:
 +
muscles. Each lateral wall of the bulb is pierced by the duct of the
 +
bulbo-urethral gland, which opens on either side of the middle lin<
 +
upon the floor of the bulbous part of the urethra fully i inch in fron
 +
of the inferior layer of the perineal membrane.
 +
 
 +
Crus Penis (Crus Corporis Cavernosi Penis). —This is the posterio]
 +
attached portion of the corpus cavernosum penis. It occupies and i:
 +
attached to a broad groove which, beginning near the ischial tuberosity
 +
winds spirally round the inner border of the ischio-pubic ramus super
 +
ficial to the inferior layer of the perineal membrane. Interiorly anc
 +
laterally it is covered by the ischio-cavernosus and lies beneath th<
 +
deep layer of superficial perineal fascia. The deep artery of the penis
 +
having pierced the inferior layer of the perineal membrane, enter:
 +
the deep surface of the crus, to be continued forwards in the centre o:
 +
the corpus cavernosum.
 +
 
 +
Deep Perineal Triangle—Boundaries — Lateral .—The crus penis
 +
covered by the ischio-cavernosus muscle. Medial .—The bulb of th(
 +
penis, covered by the bulbo-spongiosus muscle. Posterior, or Base.—
 +
The superficial transverse perineal muscle. The floor is formed by
 +
the deep layer of superficial perineal fascia, with the superficial perinea
 +
vessels and nerves. In the undisturbed position of the parts the are«
 +
of the triangle is concealed by the approximation of the bulbo-spongiosu:
 +
and ischio-cavernosus muscles. When, however, these muscles an
 +
held apart there is seen lying deeply in the area the inferior layer of the
 +
perineal membrane.
 +
 
 +
Inferior Ligament of Symphysis Pubis (Arcuate Ligament). —This i:
 +
a thick band which lies at the antero-superior part of the pubic arch
 +
It is attached superiorly to the lower part of the fibro-cartilaginou:
 +
disc, and laterally to the adjacent parts of the inner lips of the
 +
inferior pubic rami. It is about J inch in depth, and is slightly
 +
arched.
 +
 
 +
Transverse Ligament of Perineum. —This band extends transversely
 +
between the inferior pubic rami two or three lines below the inferioi
 +
ligament of symphysis. Inferiorly it is closely connected with the
 +
truncated apex of the inferior layer of the perineal membrane. Be
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
683
 +
 
 +
ween its upper border and the inferior ligament there is the opening
 +
or the backward passage of the dorsal vein of the penis.
 +
 
 +
Perineal Membrane (Triangular Ligament) (Fig. 408).—This ligament
 +
>ccupies the pubic arch, which it fills, except at its antero-superior part,
 +
vhere it is replaced by the inferior and transverse perineal ligaments!
 +
t is composed of two distinct layers, called inferior (perineal) and
 +
uperior (pelvic). These two layers are united by their bases, but
 +
elsewhere they are separated by an interval of about J inch, in which
 +
he membranous part of the urethra in the male, and the vagina and
 +
irethra in the female, along with other structures to be presently
 +
aiumerated, lie.
 +
 
 +
The inferior layer is also called the deep perineal fascia. It is
 +
 
 +
riangular, the apex being truncated. The apex is closely connected
 +
 
 +
 
 +
Crus Penis (cut).
 +
Deep Artery of Penis
 +
 
 +
 
 +
pening for Artery of the Bulb
 +
Opening for Duct of Bulbourethral Gland
 +
Inferior Layer of Perineal -Membrane
 +
 
 +
Openings for Superficial - ?
 +
 
 +
Perineal Vessels and Nerves
 +
 
 +
 
 +
Deep Layer of Superficial
 +
Perineal Fascia
 +
 
 +
 
 +
 
 +
Opening for Dorsal Vein
 +
of Penis
 +
 
 +
Dorsal Artery of Penis
 +
Artery of the Bulb
 +
 
 +
 
 +
Urethral Opening
 +
Base of Perineal Membrane
 +
 
 +
 
 +
Superior Layer of Perineal
 +
Membrane
 +
 
 +
 
 +
Fig. 408. —The Perineal Membrane.
 +
 
 +
The antero-inferior layer has been removed on the left side.
 +
 
 +
 
 +
yith the transverse perineal ligament, which may be regarded as a
 +
>art of it. Each lateral margin is attached behind or to the posterior
 +
; dge of the inner border of the ischio-pubic ramus, on which it extends
 +
ls far back as the ischial tuberosity, lying between the attachments
 +
)t the crus penis and ischio-cavernosus anteriorly and the sphincter
 +
irethrae posteriorly. In this direction it measures fully 2 inches,
 +
me base is directed downwards and backwards, and is joined by the
 +
)ase of the postero-superior layer and the deep layer of superficial
 +
)ermeal fascia. In the middle line the base is projected into a slight
 +
irocess, which is connected with the perineal body. On either side of
 +
his median process the base presents a concave margin where it sweeps
 +
iownwards and outwards to the ischial tuberosity. The length of the
 +
'Vfl° r l a y er * n the middle line is about ij inches. Its fibres are
 +
Tiefly disposed transversely. The structures which pierce this layer
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
684
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
are as follows: the urethra, the arteries of the bulb, the deep arteries
 +
of the penis, the dorsal arteries and the dorsal nerves of the penis,
 +
the superficial perineal vessels and nerves, and the ducts of the bulbourethral glands. # .
 +
 
 +
Urethral Opening. —This aperture is situated in the middle line
 +
fully i inch below the pubic angle. From the circumference of the
 +
opening an extension is given off, which forms a fascial investment
 +
for the bulb.
 +
 
 +
Openings for the Arteries of the Bulb. —These are situated one on
 +
 
 +
either side of the urethral opening.
 +
 
 +
Openings for the Deep Arteries of the Penis. —These are found near
 +
the lateral attached border, under cover of the crus penis, about i inch
 +
below the level of the pubic angle.
 +
 
 +
Openings for the Dorsal Arteries and Nerves of the Penis. —These
 +
are two in number on either side, and are situated far forward, near
 +
the pubic angle, and close to the inferior pubic ramus, the opening
 +
for the artery being medial to that for the nerve. It is to be noted that
 +
the dorsal vein of the penis has a special opening, which is situated in
 +
the median line between the inferior and transverse perineal ligaments.
 +
 
 +
Openings for the Superficial Perineal Vessels and Nerves . These
 +
are situated on either side, in the base at the line of junction with
 +
the deep layer of superficial perineal fascia.
 +
 
 +
Openings for the Ducts of the Bulbo-urethrat Glands. —Each of these
 +
is situated on either side of the urethral aperture a little behind and
 +
below the opening for the artery of the bulb.
 +
 
 +
Chief Relations — Antero-inferior. —The bulb of the penis and the
 +
crura penis, covered by their respective muscles, the superficial transverse perineal muscles, and the deep layer of superficial perineal fascia.
 +
Postero-superior. —The membranous part of the urethra, the bulbourethral glands, and the sphincter urethrae muscle.
 +
 
 +
The superior layer is weak, and is formed by the parietal pelvic
 +
fascia. It lies about \ inch above and behind the inferior layer, and
 +
extends inwards to the urethra from the back of each ischio-pubic
 +
ramus, where it lies behind the sphincter urethrae muscle. Anteriorly
 +
it blends with the sheath of the prostate posteriorly; its base joins that
 +
of the inferior layer. At each ischio-pubic ramus it is continuous with
 +
the parietal pelvic fascia. When it arrives at the urethra it changes
 +
its course, and passes backwards over the anterior border of the levator
 +
ani muscle to blend with that portion of the visceral pelvic fascia which
 +
ensheathes the prostate gland. Antero-inferiorly it is in contact with
 +
the membranous part of the urethra and sphincter urethrae muscle,
 +
whilst postero-superiorly it is related to the anterior fibres of the levator
 +
ani of each side, and forms the floor of the anterior diverticulum of
 +
the ischio-rectal fossa. The structures which pierce this layer are
 +
as follows: the urethra in the male, and the vagina and urethra in the
 +
female; and the internal pudendal vessels and dorsal nerves of the penis.
 +
 
 +
Urethral Opening. — This is often a mere cleft, in which case the
 +
superior layer may be described as being arranged in two symmetrical
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
685
 +
 
 +
halves. At this opening or cleft it becomes continuous superiorly
 +
with the capsule of the prostate gland.
 +
 
 +
Openings for the Internal Pudendal Vessels and Dorsal Nerves of the
 +
Penis .—These are situated close to the base, on either side, near the
 +
ischial ramus.
 +
 
 +
Much of the difficulty which the student experiences in understanding the anatomy of the perineum is due to the fasciae or so-called
 +
ligaments which divide the region into compartments. These fasciae
 +
are to be regarded as due to the strain thrown upon the connective
 +
tissue which everywhere surrounds here, as elsewhere, muscles, bloodvessels, glands, and other structures. In the perineum the connective
 +
tissue is particularly exposed to strain owing to its position and the
 +
support which it is called upon to give to various structures, some of
 +
which pass through it, and several of which are subject to considerable
 +
variations in size. Naturally individual differences are met not merely
 +
in the development of these fasciae, but also in the relation which they
 +
bear to the vessels and nerves. The student is advised to obtain a
 +
clear general idea of the course of the various vessels and nerves, and of
 +
their respective branches, and to remember that they are but little, if
 +
at all, deflected from a direct course to their destination.
 +
 
 +
Structures between the Layers of the Perineal Membrane.— These
 +
are as follows:
 +
 
 +
1. The membranous portion of the urethra in great part.
 +
 
 +
2. The bulbo-urethral glands..
 +
 
 +
3. The sphincter urethrae muscle.
 +
 
 +
4. The internal pudendal arteries, each lying close to the ischiopubic ramus in the sphincter urethrae muscle, and each giving off the
 +
following branches: (a) the artery of the bulb, which in turn gives off
 +
the artery to Cowper’s gland; ( b ) the deep artery of the penis; and
 +
(c) the dorsal artery of the penis.
 +
 
 +
5. A plexus of veins which receives its tributaries from the crus
 +
(corpus cavernosum) and bulb, and in which the internal pudendal
 +
venae comites take their origin.
 +
 
 +
6. The deep lymphatics of the penis and urethra.
 +
 
 +
7. The dorsal nerves of the penis, each of which lies lateral to the
 +
corresponding internal pudendal artery.
 +
 
 +
Bulbo-urethral Glands (Cowper’s). —These glands are two in number,
 +
right and left. They are situated between the two layers of the perineal
 +
membrane, where they lie above the bulb and behind the membranous
 +
portion of the urethra, one on either side of the median line. Each
 +
gland is a firm, round, and lobulated mass about the size of a small pea.
 +
Both glands are ensheathed by the lower layer of the sphincter urethrae
 +
muscle, and within this there is the special fibrous capsule which has
 +
an admixture of plain muscular tissue. The glands belong to the
 +
class of racemose or acino-tubular glands, and each is composed of
 +
several lobules. The alveoli or acini are lined with columnar cells.
 +
The ducts are two in number, right and left. They are lined with
 +
cubical epithelium, and their walls contain plain muscular tissue.
 +
 
 +
 
 +
 
 +
686
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
Each duct pierces the inferior layer of the perineal membrane on eithe
 +
side of the urethral opening a little behind and below the artery of th
 +
bulb. The duct then pierces the side of the bulb, and opens upon th
 +
floor of the bulbous part of the urethra fully i inch in front of the ir
 +
ferior layer of the perineal membrane. Each gland receives a branc'
 +
from the artery of the bulb.
 +
 
 +
 
 +
The bulbourethral glands are developed from the epithelial lining of the urc
 +
genital sinus.
 +
 
 +
 
 +
jateral
 +
 
 +
 
 +
 
 +
 
 +
Sacral
 +
 
 +
 
 +
l
 +
 
 +
 
 +
«. . T-T&T*
 +
 
 +
Superior J —■——
 +
 
 +
 
 +
superior T'^T'
 +
 
 +
Gluteal I I /AT
 +
Inferior Jfl
 +
 
 +
Gluteal
 +
 
 +
 
 +
Sacro-spinous
 +
 
 +
Ligament
 +
 
 +
 
 +
 
 +
Left Common Iliac
 +
 
 +
 
 +
Anterior Superioi
 +
Iliac Spine
 +
 
 +
 
 +
Internal Iliac
 +
Ilio-lumbar
 +
 
 +
_Posterior Division
 +
 
 +
_External Iliac
 +
 
 +
Anterior Division
 +
 
 +
 
 +
Sacro-tuber.
 +
 
 +
Ligament
 +
 
 +
 
 +
_Superior Vesical
 +
 
 +
_ __ Inferior Vesical
 +
- Deep Circumflex Iliac
 +
 
 +
-Deep Epigastric
 +
 
 +
-Obturator Nerve
 +
 
 +
-Obturator Artery
 +
 
 +
Obturator Vein
 +
 
 +
^ .Obturator
 +
Membrane
 +
 
 +
jS--* Symphysis Pubis
 +
 
 +
 
 +
Internal Pudendal Artery
 +
 
 +
Inferior Rectal
 +
 
 +
 
 +
Superficial Perineal
 +
 
 +
 
 +
Transverse Perineal
 +
 
 +
 
 +
'• Dorsal Artery of Penis
 +
j Deep Artery of Penis
 +
Artery of the Bulb
 +
 
 +
 
 +
Fig. 409.— Plan of Left Internal Iliac Artery.
 +
 
 +
 
 +
Internal Pudendal Artery. —This vessel is one of the terminal
 +
branches of the anterior division of the internal iliac, the other and
 +
larger terminal branch being the inferior gluteal. Lying at first
 +
within the pelvis, the artery passes downwards over the pyriformis
 +
muscle and sacral nerves, having the inferior gluteal artery usually
 +
behind it, and it emerges from the cavity through the lower compartment of the greater sciatic foramen. It then crosses the back of the
 +
spine of the ischium, after which it passes through the lesser sciatic
 +
foramen, and so enters the ischio-rectal division of the perineum.
 +
The vessel now courses along the outer wall of the ischio-rectal fossa,
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
687
 +
 
 +
 
 +
here, contained in the pudendal canal, it lies about ij inches above
 +
tie lower part of the ischial tuberosity. On approaching the anterior
 +
art of the fossa the artery gradually becomes more superficial, and,
 +
fter leaving the fossa, it enters the interspace between the two
 +
lyers of the perineal membrane by piercing the superior layer close
 +
d its base and near the ischial ramus. It now passes forwards and
 +
pwards, embedded in the sphincter urethrae muscle, and lying close
 +
d the ischio-pubic ramus, where it is comparatively superficial,
 +
laving given off the artery of the bulb about f inch above the base of
 +
fe perineal membrane, the vessel finally divides, about 1 inch below
 +
fe subpubic angle, into its two terminal branches, the deep and dorsal
 +
rteries of the penis.
 +
 
 +
In considering the relations and branches of the internal pudendal
 +
rtery it is convenient to divide the vessel into four parts—first, second,
 +
aird, and fourth.
 +
 
 +
 
 +
The first part represents the intrapelvic portion of the vessel, and
 +
all be found described on p. 925.
 +
 
 +
The second part is the portion of the vessel which lies upon the
 +
ack of the spine of the ischium. For a description of it see p. 539.
 +
 
 +
The third part is the part of the vessel which lies on the outer
 +
adl of the ischio-rectal fossa. It is here contained in the pudendal
 +
anal, and is situated about if inches above the lower part of the
 +
;chial tuberosity. For its relation see the pudendal canal.
 +
 
 +
Branches. —These are as follows: the inferior rectal, the superficial
 +
erineal, and the transverse perineal.
 +
 
 +
The inferior rectal (hsemorrhoidal) artery arises, either singly or
 +
1 two or three branches, from the internal pudendal immediately after
 +
: h as taken up its position in the pudendal canal. The branches pass
 +
lwards to the anal canal through the loose fat which fills the ischiosctal fossa. They are distributed to the external sphincter, levator
 +
ni, wall of the anal canal, and superficial structures of the ischiosctal division of the perineum, and they anastomose with the middle
 +
nd superior rectal arteries and the inferior rectal branches of the
 +
pposite side.
 +
 
 +
 
 +
The superficial perineal artery arises from the internal pudendal at
 +
ae anterior part of the ischio-rectal fossa. It pierces the base of
 +
tie inferior layer of the perineal membrane, and passes superficial
 +
3 (sometimes on the deep surface of) the superficial transverse perineal
 +
luscle. Its subsequent course is forwards under cover of the deep
 +
iyer of superficial perineal fascia, on the floor of the deep perineal
 +
uangle, in company with the superficial perineal nerves. On approach*g the scrotum it divides into several long slender branches, which
 +
a PPty the back of the scrotum and anastomose with the external
 +
udendal branches of the femoral artery.
 +
 
 +
The transverse perineal artery, as a rule, arises in common with
 +
superficial perineal, of which it is sometimes regarded as a branch,
 +
t may, however, arise directly from the internal pudendal immediately
 +
1 front of the origin of the superficial perineal. It is directed inwards
 +
 
 +
 
 +
688
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
and forwards to the perineal body, lying superficial to the superfici
 +
transverse perineal muscle, and beneath the deep layer of superfici
 +
perinea] fascia. It supplies the muscles which meet at the perine
 +
body, and anastomoses with its fellow of the opposite side.
 +
 
 +
The Pudendal (Alcock’s) Canal. —This canal is situated in the out*
 +
wall of the ischio-rectal fossa, and is formed by the obturator fasci
 +
Its contents from below upwards are as follows: (i) the perineal divisic
 +
of the pudendal nerve; (2) the third part of the internal pudendal artei
 +
with its venae comites; and (3) the dorsal nerve of the penis.
 +
 
 +
The fourth part of the internal pudendal artery lies between tl
 +
two layers of the perineal membrane. It enters this interspace t
 +
piercing the superior layer of that membrane close to its base ar
 +
near the ischial ramus. It is embedded in the sphincter urethr
 +
muscle, and is comparatively superficial. As it lies near the ischii
 +
pubic ramus it has a vena comes on either side of it, and the dors;
 +
nerve of the penis is lateral to it.
 +
 
 +
Branches. —These are as follows: the artery of the bulb, the dee
 +
artery of the penis, and the dorsal artery of the penis.
 +
 
 +
The artery of the bulb arises from the internal pudendal about \ inc
 +
above the base of the perineal membrane, and passes transverse]
 +
inwards in the substance of the sphincter urethrae muscle. On a]
 +
proaching the urethra it turns forwards, and, having pierced tl
 +
sphincter urethrae, it passes through an opening in the inferior lay*
 +
of the perineal membrane at the side of the urethral aperture. ]
 +
then enters the bulb, and is continued onwards in the corpus spoi
 +
giosum as far as the glans penis, the erectile tissue of which parts
 +
supplies. It anastomoses with its fellow of the opposite side and wit
 +
the dorsal arteries of the penis; whilst between the two layers of tl
 +
perineal membrane the artery furnishes a branch to the bulbo-urethr;
 +
gland of the corresponding side.
 +
 
 +
The deep artery of the penis is one of the two terminal branches (
 +
the internal pudendal, and is somewhat larger than the dorsal arter
 +
of the penis, which is the other terminal branch. It arises abor
 +
1 inch below the subpubic angle, and piercing the sphincter urethr
 +
muscle and the inferior layer of the perineal membrane close to th
 +
ischio-pubic ramus, enters the crus on its inner surface. Giving a fe 1
 +
branches backwards, it is continued forwards in the centre of the corpr
 +
ca,vernosum as far as the distal end of that body, the erectile tissue c
 +
which it supplies.
 +
 
 +
The dorsal artery of the penis is the continuation of the interne
 +
pudendal. For a very short distance it lies between the two layei
 +
of the perineal membrane embedded in the sphincter urethrae musclt
 +
Piercing this muscle and the inferior layer of the membrane near it
 +
upper part, it ascends between the crus and the symphysis pubis
 +
Its subsequent course is between the two layers of the suspensor
 +
ligament of the penis, and then along the dorsum of the organ, wher
 +
it has the centrally-placed dorsal vein on its inner side and the dorsa
 +
nerve of the penis on its outer. On arriving at the neck of the peni
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
689
 +
 
 +
 
 +
ends in branches for the supply of the glans and prepuce, anastomosing
 +
th its fellow of the opposite side and the arteries of the bulb. In its
 +
urse along the dorsum of the penis the artery gives off many branches,
 +
me of which supply the skin and anastomose with the superficial
 +
;ternal pudendal of the femoral, while others pierce the fibrous sheath
 +
 
 +
the corpus cavernosum to supply its erectile tissue, these latter
 +
Lastomosing with the deep artery of the penis.
 +
 
 +
Varieties of the Internal Pudendal Artery—1. Trunk. —The vessel is occasionly of small size, and may terminate in the artery of the bulb, or in the superial perineal artery. In these cases an accessory pudendal artery is present,
 +
lich supplies the deficiencies. This vessel usually arises from the first or
 +
trapelvic part of the internal pudendal, though it may spring from an inferior
 +
:sical artery. Its course is forwards along the side of the bladder, then along
 +
e side of the prostate gland to the perineal membrane, which it pierces above
 +
e membranous part of the canal, and so reaches the root of the penis. The
 +
cessory pudendal furnishes the deep artery of the penis and the dorsal artery of
 +
e penis, and in some cases the artery of the bulb.
 +
 
 +
2. Artery of the Bulb. —Sometimes two arteries are present on one side;
 +
metimes the artery is absent on one side; and sometimes it is of very small
 +
le. A much more important variety of this artery affects its origin. It may
 +
ise from the third part, at ±he front of the ischio-rectal fossa, reaching the bulb
 +
Dm behind. In these cases the artery cannot escape division in the operation
 +
 
 +
lateral lithotomy. In other cases it may arise from an accessory pudendal
 +
tery, when it will lie farther forwards than usual.
 +
 
 +
3. Dorsal Artery of the Penis. —This vessel may arise from the obturator
 +
tery in the obturator canal, or from one of the external pudendal branches of
 +
ie femoral artery.
 +
 
 +
Veins. —Lying in each sphincter urethrae muscle there is a plexus
 +
: veins, which receives its tributaries from the corresponding corpus
 +
ivernosum and one half of the corpus spongiosum and bulb. The
 +
iternal pudendal venae comites arise on either side from this plexus,
 +
id accompany the internal pudendal artery as far back as the upper
 +
irder of the spine of the ischium, one lying on either side of the
 +
essel. Here they join to form one trunk, which enters the pelvis
 +
irough the lower compartment of the greater sciatic foramen, and
 +
irminates in the internal iliac vein. They receive as tributaries the
 +
'ansverse perineal, superficial perineal, and inferior rectal veins, as
 +
ell as a few veins from the gluteus maximus and lateral rotator muscles,
 +
he inferior rectal (hsemorrhoidal) veins take their origin in a plexus
 +
f veins which is situated immediately underneath the mucous memrane of the anal canal. Having pierced the external sphincter muscle,
 +
ley cross the ischio-rectal fossa through its loose fat and, being ultilately reduced to two or three in number, join the internal pudendal
 +
enae comites.
 +
 
 +
It is to be noted that, though there are two dorsal arteries, there
 +
> only one dorsal vein, which takes the following course: after leaving
 +
tie dorsum of the penis it passes through an opening between the in^rior and transverse perineal ligaments, where it communicates on
 +
tiller side with the venous plexuses from which the internal pudendal
 +
eins take their origin. Having entered the cavity of the pelvis, it
 +
 
 +
44
 +
 
 +
 
 +
 
 +
690
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
divides into two branches, right and left, which join the prostat
 +
plexus of veins.
 +
 
 +
Lymphatics. —The superficial lymphatics of the perineum, includii
 +
those of the anus, pass to the superficial inguinal glands , which 1
 +
immediately below the inguinal ligament, while the deep lymphatl
 +
accompany the internal pudendal vessels through the ischio-rectal fos;
 +
and buttock into the pelvis and pass to the internal iliac glands.
 +
 
 +
Pudendal Nerve. —The pudendal nerve is one of the termin
 +
branches of the sacral plexus, and derives its fibres from the ventr
 +
division of the second, the lower branch of the third, and the upp<
 +
 
 +
 
 +
Scrotum
 +
 
 +
 
 +
Deep Layer of Superficial
 +
Perineal Fascia (right half)
 +
 
 +
 
 +
Superficial Perinealf
 +
Nerves f
 +
 
 +
 
 +
Long Perineal Nerve
 +
 
 +
 
 +
Superficial Transverse
 +
Perineal Muscle
 +
 
 +
 
 +
Inferior Hasmorrhoidal
 +
Nerve
 +
 
 +
 
 +
Gluteal Cutaneous
 +
Branches of Posterior
 +
Cutaneous Nerve of Thigh
 +
 
 +
 
 +
Perforating Cutaneous Nerve
 +
 
 +
 
 +
 
 +
-Perineal Body
 +
 
 +
-Superficial Perineal Artery
 +
 
 +
-Transverse Perineal Artery
 +
 
 +
__ Internal Pudendal Artery ii
 +
the Pudendal Canal
 +
V— Inferior Rectal Artery
 +
 
 +
 
 +
- Gluteal Cutaneous Branche:
 +
of Inferior Gluteal Artery
 +
 
 +
 
 +
Perineal Branch of 4th Sacral Nerve
 +
 
 +
Fig. 410.—Dissection of the Male Perineum.
 +
 
 +
On the left side the bulbo-spongiosus has been removed and the crus
 +
 
 +
 
 +
penis cut.
 +
 
 +
 
 +
branch of the fourth sacral nerves, the majority of its fibres bein
 +
derived from the lower branch of the third. Leaving the pelvi
 +
through the lower compartment of the greater sciatic foramen, th
 +
nerve crosses the sacro-spinous ligament near its attachment to th
 +
spine of the ischium, lying under cover of the gluteus maximus an*
 +
on the inner side of the internal pudendal vessels. It then passe
 +
through the lesser sciatic foramen, and so enters the pudendal cana
 +
in the outer wall of the ischio-rectal fossa. Immediately after doinj
 +
so, it divides into three branches—namely, inferior haemorrhoidal
 +
perineal, and dorsal nerve of the penis.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
691
 +
 
 +
 
 +
The inferior hsemorrhoidal nerve, which may have an independent
 +
-igin from the sacral plexus, passes inwards across the ischio-rectal
 +
issa to the region of the anus, and is distributed to the external
 +
>hincter muscle and the skin around the anus.
 +
 
 +
The perineal nerve is a large branch which passes forwards in the
 +
udendal canal, being the lowest of its contents. It ultimately divides
 +
ito superficial and deep branches.
 +
 
 +
The superficial branches are two in number, and are called the
 +
iteral and medial scrotal nerves. Both nerves, having emerged from
 +
le pudendal canal into the ischio-rectal fossa, pass forwards and
 +
ierce the base of the inferior layer of the perineal membrane. They
 +
ien run forwards with the superficial perineal artery under cover of
 +
re deep layer of superficial perineal fascia, and on approaching
 +
tie back of the scrotum they divide into long slender cutaneous
 +
ranches.
 +
 
 +
In the anterior division of the perineum the two superficial perineal
 +
erves communicate freely, and are accompanied by the long perineal
 +
erve (of Soemmering), which is a branch of the posterior cutaneous
 +
erve of the thigh. This nerve, having pierced the fascia lata about
 +
inch in front of the ischial tuberosity, passes inwards over the ischioubic ramus and through the deep layer of superficial perineal fascia,
 +
t then runs forwards and inwards beneath this fascia to the scrotum,
 +
^ing on the ischio-cavernosus muscle, close to the ischio-pubic ramus,
 +
upplying the skin of the scrotum, and communicating with the
 +
ateral posterior scrotal nerve.
 +
 
 +
The deep branch of the perineal nerve furnishes offsets which, with
 +
>ne exception, are muscular in their distribution, and supply the
 +
interior part of the external sphincter, the anterior part of the levator
 +
mi, the superficial transverse perineal, the ischio-cavernosus, and the
 +
mlbo-spongiosus. The non-muscular branch, called the nerve of the
 +
)ulb, pierces the bulbo-spongiosus muscle and the wall of the bulb,
 +
0 be distributed to the erectile tissue of the corpus spongiosum and
 +
he mucous membrane of the spongy part of the urethra.
 +
 
 +
The dorsal nerve of the penis is at first contained in the pudendal
 +
:anal, where it lies above the internal pudendal vessels. Having
 +
emerged from that canal, it pierces the superior layer of the perineal
 +
nembrane near its base. It then passes forwards and upwards, with
 +
:he fourth part of the internal pudendal artery, between the two
 +
ayers of the perineal membrane, in which situation it lies on the outer
 +
fide of the internal pudendal vessels, and close to the ischio-pubic
 +
ramus, being embedded in the sphincter urethrae muscle. Its subsequent course is similar to that of the dorsal artery of the penis, which
 +
it accompanies. On the dorsum of the penis, where it lies lateral to
 +
the dorsal artery, it is continued as far as the glans, where it ends in
 +
branches for the glans and prepuce. As the nerve lies between the
 +
two layers of the perineal membrane, it gives branches to the sphincter
 +
urethrae muscle, and it also furnishes the nerve of the corpus cavernosum. This latter nerve, having pierced the sphincter urethrae and
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
692
 +
 
 +
inferior layer of the perineal membrane, enters the crus and is continue
 +
forwards in the corpus cavernosum to supply its erectile tissue. A
 +
the nerve passes along the dorsum of the penis, it supplies numerou
 +
cutaneous branches.
 +
 
 +
Structures divided in Left Lateral Lithotomy. —The structures divided in thi
 +
operation are as follows: (1) the skin; (2) the subcutaneous layer of the super
 +
ficial fascia; (3) the deep layer of the superficial fascia or the fascia of Colies
 +
(4) the transverse perineal vessels; (5) the superficial transverse perineal muscle
 +
(6) the inferior hsemorrhoidal nerve and the inferior rectal vessels; (7) the bass
 +
part of the inferior layer of the perineal membrane; (8) the sphincter urethr;
 +
muscle and the plexus of veins embedded in it; (9) the membranous part of th
 +
urethra; (10) the superior layer of the perineal membrane; (11) the anterior fibre
 +
of the levator ani muscle; (12) a portion of the left lateral lobe of the prostat
 +
gland, with its capsule and some of the veins of the prostatic plexus; and (13) th
 +
prostatic urethra.
 +
 
 +
Structures to be avoided. —The structures to be avoided are as follows: (1) th
 +
rectum; (2) the internal pudendal vessels as they lie in the pudendal canal
 +
(3) the artery of the bulb; and (4) the common ejaculatory duct.
 +
 
 +
 
 +
FEMALE PERINEUM.
 +
 
 +
The female perineum is divided into three regions—uro-genita
 +
perineum proper (as defined by the obstetrician), and anal. The uro
 +
genital division is situated at the anterior part, and comprises th
 +
pudendum and uro-genital cleft. The perineum proper is situate<
 +
between the posterior part of the uro-genital cleft and the anus* Th'
 +
anal division is situated as in the male.
 +
 
 +
Uro-genital Division.
 +
 
 +
The uro-genital division contains the external uro-genital organs
 +
These collectively constitute the pudendum muliebre or vulva, am
 +
comprise the following parts: the mons pubis; labia majora; labi;
 +
minora; clitoris; vestibule; external urethral orifice; vaginal orifice
 +
including the hymen of the carunculse hymenales; frsenulum pudendi
 +
vestibular fossa; bulbs of the vestibule; and the greater vestibula
 +
glands.
 +
 
 +
The mons pubis (Veneris) is an eminence situated in front of anc
 +
above the upper part of the symphysis pubis. It is produced by c
 +
collection of adipose tissue, the skin over which is more or less freei}
 +
provided with hair after the age of puberty.
 +
 
 +
The labia majora are two thick, round folds of skin, which ar(
 +
directed from before backwards, with a slight inclination downwards
 +
The length of each is about 3 inches. Posteriorly they become thin
 +
and fading away lose themselves in the anterior part of the perineun
 +
proper, about 1 inch in front of the anus. The junction to which the
 +
name of the posterior commissure has been given is of rare occurrence
 +
Anteriorly they retain their thick, round character, and become con
 +
tinuous with the mons pubis, forming the so-called anterior commissure. Each labium majus has two surfaces, outer and inner. Tht
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
693
 +
 
 +
 
 +
tin covering the outer convex surface is somewhat dark in colour,
 +
ke that of the scrotum, and contains numerous sebaceous glands of
 +
trge size. It is also more or less freely provided with hair after the
 +
ge of puberty, except towards the posterior part. The inner flat
 +
jrface forms the lateral boundary of the uro-genital cleft, and touches
 +
lat of the opposite side. The skin covering this surface is smooth
 +
nd free from hair, and presents the openings of the ducts of sebaceous
 +
lands. Each labium majus contains adipose and areolar tissues, and
 +
small amount of dartos tissue. The ligamentum teres uteri of each
 +
ide loses itself in this labium, and superficial and deep fasciae from
 +
tie lower part of the anterior abdominal wall also enter it. The
 +
ssure between these labia is called the uro-genital cleft (rima pudendi),
 +
nd is almost horizontal, its direction being antero-posterior. The
 +
 
 +
 
 +
Mons Pubis—«=.
 +
 
 +
 
 +
M\u
 +
 
 +
Anterior Commissure
 +
 
 +
jf
 +
 
 +
 
 +
 
 +
Labium Majus
 +
 
 +
 
 +
- Labium Minus
 +
' External Urethral Orifice
 +
 
 +
 
 +
-External Orifice of Vagina
 +
 
 +
 
 +
Vestibular Fossa
 +
Frenulum Labiorum
 +
Posterior Commissure
 +
 
 +
 
 +
Fig. 411.—The External Genital Organs of the Female.
 +
 
 +
lood-supply and nerve-supply of the labia majora correspond with
 +
hose of the scrotum.
 +
 
 +
The lymphatics arise from a rich network in each labium majus, these networks being connected with each other across the median line. The efferent
 +
essels pass to the superficial inguinal glands. Some vessels are said to cross
 +
tie median line and terminate in the glands of the opposite side.
 +
 
 +
The labia minora (nymphse) are two narrow, more or less pendulous
 +
olds of integument, which are situated in the uro-genital space, each
 +
png internal to the corresponding labium majus. They become coninuous with each other anteriorly, in the region of the clitoris, a
 +
hort distance from the anterior commissure, in a manner to be presently
 +
lescribed. From this point they diverge as they pass backwards, and
 +
0 form the lateral boundaries of the space called the vestibule. Each
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
694
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
terminates posteriorly by blending with the inner surface of the com
 +
sponding labium majus, or in some cases by becoming continuous wit'
 +
its fellow, forming the frenulum labiorum. Each labium minus ha
 +
two surfaces, outer and inner, and two borders, superior and inferioi
 +
The outer surface is in contact with the inner surface of the labiur
 +
majus of the same side, and the inner surface touches that of the oppc
 +
site labium minus. Each surface is covered by a modified form of skir
 +
that on the inner surface being extremely delicate, and being some
 +
what like mucous membrane. The true mucous membrane, howevei
 +
only commences at the inner side of the base or superior attache
 +
border of the labium minus. The labia minora, previous to thei
 +
union anteriorly, divide each into two laminae. The upper and large
 +
lamina passes over the clitoris, and becomes continuous with that c
 +
the opposite side, thus forming a cap for that organ, called the prepuc
 +
of clitoris. The lower and smaller lamina passes below the clitoris
 +
where it also becomes continuous with that of the opposite side. A
 +
the line of junction of the two lower laminae they are attached to th
 +
under surface of the clitoris, thus forming the frenulum of clitoris
 +
The labia minora are destitute of both hair and fat, but they contai
 +
sebaceous glands. They sometimes attain a large degree of develop
 +
ment, in which cases they project through the uro-genital cleft. I:
 +
some African women they become so much developed as to reach dow:
 +
to the knees. When this occurs they form what has been called th
 +
Hottentot apron. The labia minora are homologous with the floo
 +
of the spongy part of the urethra, the skin of the penis, and the prepuc
 +
in the male.
 +
 
 +
Development of the Labia. —The opening of the uro-genital sinus extend
 +
ventrally on to the base of the genital eminence. The opening is bordered by th
 +
labio-scrotal folds, which also extend to the eminence. These folds, enlargin
 +
slightly, become the labia minora ; the labia minora thus extend to the lowe
 +
aspect of the eminence, which becomes the clitoris. The labia majora are modi
 +
fications of the genital swellings, which in the male become the scrotum. Th
 +
fusion of the labio-scrotal folds in the male converts what is, in the female, th
 +
vestibule of the vulva into the spongy urethra, and the laterally placed genitc
 +
swellings, meeting over the closed folds, constitute the scrotum.
 +
 
 +
The clitoris is situated in the uro-genital cleft a little behind th
 +
anterior commissure, and is composed of two corpora cavernosa an<
 +
a glans. Each corpus cavernosum occupies, by means of a crus, \
 +
groove which winds spirally round the inner border of the ischio-pubi
 +
ramus, the crus being covered by the ischio-cavernosus or erecto
 +
clitoridis muscle, and lying superficial to the inferior layer of th
 +
perineal membrane. The two corpora cavernosa unite by their inne
 +
flattened surfaces, and so form the body of the clitoris, which is abou
 +
ij inches long. The septum, which is interposed at the line of junctioi
 +
of the corpora cavernosa, is interrupted by vertical clefts, and is calle(
 +
the commissure of bulb (septum pectiniforme). The dorsal surface o
 +
the clitoris at its upper end is attached to the front of the symphysi
 +
pubis by a small suspensory ligament, and the distal end of the orgai
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
695
 +
 
 +
 
 +
; capped by an imperforate glans. The glans, which caps the corpora
 +
avernosa, is composed of erectile tissue, and is extremely sensitive,
 +
t is provided with a prepuce and a frenulum, both of which are continous with the labia minora. The organ is composed of erectile tissue.
 +
 
 +
The clitoris is the homologue of the penis, from which it differs in
 +
he following respects: (1) the only part of a corpus spongiosum which
 +
: possesses is the glans (the part of the corpus spongiosum of the male
 +
diich lies between the bulb and the glans penis being represented in
 +
he female by the pars intermedia of the bulb of the vestibule; (2) it
 +
.oes not contain the female urethra; and (3) its component parts are
 +
auch smaller than those of the penis. In reality the clitoris is a
 +
liminutive penis, minus the corpus spongiosum and the urethra. It is
 +
leveloped from the genital eminence.
 +
 
 +
Lymphatics. —The lymphatics of the prepuce of the clitoris accompany those
 +
if the labia majora, and pass to the superficial inguinal glands.
 +
 
 +
The lymphatics of the glans clitoridis run on the dorsum of the clitoris towards
 +
he front of the symphysis pubis, where they form a network. The vessels
 +
vhich emerge from either side of this network have the following destinations:
 +
1) Some pass to the deep inguinal glands, and thence through the femoral canal
 +
o the internal chain of the external iliac glands ; and (2) others traverse the
 +
nguinal canal and terminate in the lowest gland of the outer chain of the external
 +
 
 +
liac glands. . .
 +
 
 +
The lymphatics of the corpora cavernosa pass to the internal iliac glands on
 +
 
 +
iither side.
 +
 
 +
The vestibule is the space which is enclosed by the labia minora, and
 +
s so called because it is the ‘ porch ’ of the vagina. It is triangular, the
 +
ipex, which is in front, being formed by the glans clitoridis, the lateral
 +
Doundaries by the labia minora, and the base by the frenulum labiorum.
 +
It is 2 inches or more in length, and presents a smooth surface covered
 +
by a mucous membrane of stratified squamous epithelium. Half-way
 +
ilong the vestibule in the middle line, and immediately in front of the
 +
external orifice of the vagina, is a slight prominence with somewhat
 +
irregular margins. Upon this prominence the external urethral orifice
 +
is situated at a point 1 inch behind the clitoris. The irregular prominence
 +
serves as a guide to this opening.
 +
 
 +
The vestibule represents the remains of the uro-genital sinus.
 +
 
 +
The external orifice of the vagina is an antero-posterior cleft, having
 +
an elliptical shape when partially dilated. The portion of the vagina
 +
close above it is the narrowest part of the passage. For the description of the vagina, see Female Pelvis.
 +
 
 +
The hymen in its normal condition is a thin semilunar fold of
 +
mucous membrane which is stretched across the posterior third, or
 +
half, of the external orifice of the vagina. Its concave border, which
 +
is free, is directed forwards and upwards. Sometimes the hymen completely surrounds the circumference of the orifice, an aperture being
 +
left in its centre. In other cases it stretches over the entire opening,
 +
but is perforated by apertures which give it a cribriform appearance.
 +
In rare cases it is an entire membrane, completely shutting off the
 +
vaginal canal from the uro-genital cleft, and it is then spoken of as an
 +
 
 +
 
 +
 
 +
6g6
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
imperforate hymen. In some cases, even in the virgin, it is entire
 +
absent.
 +
 
 +
The hymen begins to appear about the fifth month of intra-uterine life
 +
a fold of mucous membrane at the point where the vagina opens into the ui
 +
genital sinus.
 +
 
 +
The carunculae hymenales (myrtiformes) are small elevations whii
 +
represent the remains of the hymen after its rupture. Though calli
 +
carunculce (fleshy), they are really mucous excrescences.
 +
 
 +
The frenulum labiorum (fourchette) is a crescentic fold formed 1
 +
the union posteriorly of the two labia minora. It is not always reco
 +
nizable, and is best marked in early life.
 +
 
 +
 
 +
 
 +
Right Greater Vestibular Gland
 +
and its Duct
 +
 
 +
Fig. 412.—Dissection showing the Bulbs of Vestibule and Greater
 +
Vestibular Glands (modified from Kobelt).
 +
 
 +
The cross on either side of the vaginal orifice shows the position of the
 +
opening of the duct of the greater vestibular gland.
 +
 
 +
The vestibular fossa (navicularis) is a small depression which lie
 +
between the hymen and the frenulum labiorum.
 +
 
 +
The bulbs of vestibule (Fig. 412) are two ovoid masses of erectil
 +
tissue 1 inch in length, which are situated on either side of the vestibul
 +
beneath the mucous membrane. Each bulb is covered by a delicat
 +
fibrous capsule derived from the inferior layer of the perineal membran(
 +
superficial to which the bulb of either side lies. The outer surface i
 +
convex, and is covered by one half of the bulbo-spongiosus muscle
 +
the inner surface is slightly concave, and is covered by the vagina
 +
mucous membrane. Posteriorly the bulbs diverge, and anteriorly
 +
having become narrow, they pass upwards and forwards, and ultimate!
 +
meet in the middle line, where they are attached to the inferior layer 0
 +
the perineal membrane. In front of the bulbs there is a plexus of vein
 +
which is continuous behind with their erectile tissue, and in front witl
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
697
 +
 
 +
 
 +
that of the glans clitoridis. This plexus of veins is known as the pars
 +
intermedia. It receives veins from the labia minora, and its blood is
 +
conveyed into the vaginal plexus.
 +
 
 +
The bulbs of the vestibule together represent the bulb of the male
 +
urethra, which latter presents on its under surface a faint groove in
 +
the middle line, indicating a bilateral origin. The pars intermedia
 +
is regarded as representing that part of the male corpus spongiosum
 +
which extends from the bulb to the glans penis.
 +
 
 +
The greater vestibular glands (Bartholin’s glands) belong to the class
 +
of racemose or acino-tubular glands. They are two in number, right
 +
and left, and each resembles a small bean. They lie on either side of
 +
the external orifice of the vagina, immediately behind the posterior
 +
extremities of the bulbs of the vestibule, into which certain of their
 +
lobules may project. The duct of each gland is about £ inch long, and
 +
opens in the angle between the attached border of the labium minus
 +
 
 +
 
 +
 
 +
Fig. 413.—The External Genital Organs at the End of the Indifferent
 +
Stage seen from the Front and from the Side.
 +
 
 +
GF, labio-scrotal fold; GS, genital swelling; GT, genital tubercle.
 +
 
 +
and the hymen or its remains a little in front of the vestibular fossa.
 +
The orifices of these ducts are usually plainly visible to the naked eye.
 +
 
 +
These glands are homologous with the bulbo-urethral glands, and
 +
their structure is similar.
 +
 
 +
The greater vestibular glands are developed from the lining epithelium of the
 +
uro-genital sinus.
 +
 
 +
The external uro-genital organs of the female have received the
 +
name of vulva. As this word, however, literally signifies a ‘ covering/ it is strictly applicable only to the labia majora, which by their
 +
approximation form a covering for the uro-genital cleft and its contents.
 +
 
 +
Development of the External Genital Organs.
 +
 
 +
In the early stages no sexual differences are apparent in the development of the external genital organs. The chief parts concerned
 +
are (1) the genital eminence, (2) the genital groove, (3) the labio-scrotal
 +
folds, and (4) the genital swellings.
 +
 
 +
 
 +
6 g8
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
Female External Organs. —The surface-depression corresponding
 +
the cloacal membrane, which bounds the cloaca postero-inferior]
 +
is known as the cloacal depression. As the cloaca becomes divide
 +
into two compartments—dorsal or intestinal, and ventral or ur
 +
genital—by the cloacal or uro-rectal septum, the cloacal membra;
 +
is also divided into two parts—dorsal or anal, and ventral or ur
 +
genital. Moreover, the superficial cloacal depression is likewi
 +
divided into two parts—dorsal, which is called the anal depressn
 +
or proctodceum ; and ventral, which is known as the uro-genital a
 +
pression, and is somewhat cleft-like. When the uro-genital portic
 +
of the cloacal membrane ruptures, the uro-genital sinus or canal cor
 +
municates with the exterior by means of the uro-genital opening <
 +
cleft.
 +
 
 +
The formation of the subdivisions of the cloaca is described ar
 +
figured on p. 98, and the slit-like opening of the uro-genital sim
 +
 
 +
 
 +
Male. Female.
 +
 
 +
RapM of Penis^ Gians Penis Gians Clitoridis Genital Swelling
 +
 
 +
 
 +
 
 +
Fig. 414.—Development of the External Genital Organs.
 +
 
 +
is seen to extend forward on the lower aspect of the growing genita
 +
tubercle.
 +
 
 +
The female external genital organs are developed around the uro
 +
genital opening. At the cephalic part of the primitive vestibule ;
 +
small tubercle, called the genital eminence or tubercle, makes it
 +
appearance in the median line. On the lower, or vestibular, surfac<
 +
of this eminence a furrow, called the genital groove, marks the forwarc
 +
prolongation of the uro-genital opening. The lips of this groove
 +
which are laterally disposed, are called the labio-scrotal folds. Or
 +
either side of the genital eminence, external to the corresponding genita
 +
fold, a low ridge makes its appearance. These ridges are known as
 +
the genital swellings. They are continuous with each other on the
 +
ventral aspect of the genital eminence, and they extend dorsalwards ;
 +
lying on either side of the vestibule, and finally meeting behind in the
 +
perineum.
 +
 
 +
The genital eminence undergoes lengthening, and gives rise to the
 +
plitons, The terminal extremity of the eminence becomes enlarged,
 +
 
 +
 
 +
 
 +
THE ABDOMEN 699
 +
 
 +
md forms the glans clitoridis, whilst the remainder gives rise to the
 +
zorpora cavernosa clitoridis.
 +
 
 +
The labio-scrotal folds, which in the male fuse, enclosing the spongy
 +
part of the urethra, and forming the corpus spongiosum penis, remain
 +
separate in the female, and form the labia minora. The genital swellings, which in the male come together and form the scrotum, remain
 +
separate in the female, and give rise to the labia majora. The ventral
 +
portions of the external swellings, which are continuous with each
 +
Dther on the ventral aspect of the genital eminence, form the mons
 +
pubis.
 +
 
 +
The hymen appears as a semilunar fold of mucous membrane,
 +
extending as a rule over the dorsal part of the external orifice of the
 +
vagina.
 +
 
 +
 
 +
 
 +
Fig. 415.— Figures of Male and Female Organs at the End of
 +
 
 +
the Second Month.
 +
 
 +
 
 +
The labio-scrotal fold (GF) is being carried forward on the base of the penile
 +
prominence in the male. The clitoris is very long in the female, but the
 +
folds and the genital swellings (GS) are less prominent.
 +
 
 +
The greater vestibular glands are developed laterally as evaginations
 +
of the epithelial lining of the caudal part of the uro-genital sinus, which
 +
part, when expanded, forms the vestibule.
 +
 
 +
The bulbs of the vestibule and the pars intermedia are developed as
 +
masses of erectile tissue close to the labia minora and clitoris.
 +
 
 +
Male External Organs. —The genital tubercle undergoes lengthening,
 +
although this is not so marked a feature in the male at first as it is in
 +
the female. The lengthening, occurring later, appears to be of a
 +
different nature than in the female, for the parts of the labio-scrotal
 +
folds which are related to the tubercle seem to be drawn out with it in
 +
its growth, and help to form the shaft of the penis. The eminence
 +
forms the glans , and the corpora cavernosa are developed partly from
 +
the tubercle, but mainly from the genital folds. With the elongation
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
700
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
and general growth the groove on the lower surface is drawn out arj
 +
deepened. The labio-scrotal folds forming the lips of the groove, whic
 +
remain open in the female, close over it in the male, so that the groo\
 +
is converted into the spongy urethra.
 +
 
 +
It is difficult to decide whether the lips fuse from behind forward, or the
 +
hinder junction is simply carried forward with the folds on the lengthening peni
 +
The presence of a raphe on the scrotal aspect of the penis seems to suggest the
 +
fusion occurs.
 +
 
 +
The opening of the uro-genital sinus on the surface is thus carrie
 +
forward more and more, reaching the lower surface of the penil
 +
prominence (Fig. 416). Continuation of the closing process shuts 0:
 +
the spongy urethra from the surface, but about the time this take
 +
place the urethra in the glans is formed by hollowing out of the ectc
 +
dermal plate which occupied the (potential) groove on the eminence
 +
 
 +
 
 +
 
 +
Fig. 416. —Male External Organs during the Third and Early
 +
 
 +
Part of Fourth Month.
 +
 
 +
the canal formed in this way becomes continuous with the spongy
 +
urethra.
 +
 
 +
The spongy part of the urethra extends as far as the uro-genital
 +
sinus, from the lower part of which the prostatic and membranous
 +
parts of the canal are developed.
 +
 
 +
In rare cases the genital folds fail to unite over some portion of the
 +
genital groove. In such cases the spongy urethra opens externally
 +
on the under, or scrotal, aspect of the penis, and the condition is
 +
known as hypospadias.
 +
 
 +
The labio-scrotal folds, which enclose the spongy part of the urethra,
 +
acquire erectile tissue and constitute the corpus spongiosum penis.
 +
The genital eminence, having lengthened considerably, and having
 +
acquired erectile tissue, gives rise to parts of the corpora cavernosa
 +
penis, whilst its terminal enlargement forms the glans penis.
 +
 
 +
The genital swellings, which in the female remain separate and form
 +
the labia majora,, unite in the male and give rise to the scrotum. The
 +
line of fusion is indicated in adult life by the scrotal raphe.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
701
 +
 
 +
 
 +
It is to be noted that, whilst the prostatic and membranous portions
 +
 
 +
the male urethra are developed from the lower part of the urolital sinus, and are therefore non-penile , the spongy portion of the
 +
aal is developed from (1) the genital groove on the lower surface of the
 +
aital eminence, and (2) the internal genital folds. The spongy part
 +
the urethra is therefore penile.
 +
 
 +
The bulb of the corpus spongiosum penis represents the bulbs of
 +
! vestibule of the female, and the portion of the corpus spongiosum
 +
nis between the bulb and the glans penis represents the pars inter'dia of the body of the clitoris in the female.
 +
 
 +
Perineum Proper.
 +
 
 +
The perineum proper is the region which lies between the anus and
 +
e vestibule. It is in this division that the perineal body is situated.
 +
 
 +
Perineal Body. —It is situated between the anus and the vaginal
 +
[fice. It is triangular in outline, and is about ib inches in breadth.
 +
 
 +
 
 +
 
 +
Fig. 417. —Female Bony Pelvis from Below.
 +
 
 +
ST =sacro-tuberous ligament; IP =ischio-pubic ramus.
 +
 
 +
is bounded in front by the posterior wall of the vagina, behind by the
 +
iterior wall of the anal canal, and inferiorly by the skin. The perineal
 +
>dy is produced by a thickening of connective tissue, with a free
 +
Imixture of elastic tissue and a few muscular fibres derived from the
 +
:ternal sphincter, levatores ani, and bulbo-spongiosus muscles. It
 +
rves as a support to the posterior wall of the vagina. During parturi3 n it becomes greatly stretched, but its elastic tissue usually guards
 +
against rupture.
 +
 
 +
Perineal Membrane. —The perineal membrane resembles that of
 +
te male in being composed of two layers, inferior and superior.
 +
 
 +
The inferior layer, on account of the greater width of the pubic
 +
xh in the female, is broader than in the male, though it is more
 +
^definite on account of its being pierced by the vagina. It is attached
 +
t either side to the posterior margin of the inner border of the ischioubic ramus, and anteriorly blends with the transverse perineal ligament. In the middle line, where it is pierced by the vagina, it blends
 +
ith the wall of that canal. Its base is joined by a somewhat indefinite
 +
 
 +
 
 +
 
 +
 
 +
 
 +
702
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
layer of fascia representing the deep layer of superficial perineal fasc
 +
in the male, and by the superior layer. The openings in the inferi
 +
layer are similar to those in the male, with this exception, that t
 +
ducts of the greater vestibular glands do not pierce it as the ducts
 +
the bulbo-urethral glands do in the male, the greater vestibular glan
 +
being situated superficial to this layer. The urethral opening is situab
 +
i inch below the symphysis pubis. The opening for the vagina, whi<
 +
is of large size, lies below the urethral orifice, from which it is separati
 +
by a few fibres. The openings for the arteries of the bulbs of £
 +
vestibule are situated one on either side of the vaginal opening. T
 +
openings for the deep artery of clitoris, for the dorsal artery and ner
 +
of the clitoris, and for the superficial perineal vessels and nerves, a
 +
situated as in the male.
 +
 
 +
It is to be noted that the dorsal vein of the clitoris, like the corr
 +
sponding vessel in the male, passes between the inferior and transver
 +
perineal ligaments.
 +
 
 +
The superior layer is similar to the corresponding layer in the mal
 +
and presents openings for the urethra, vagina, and internal pudend
 +
vessels and pudendal nerves of each side.
 +
 
 +
Anal Division.
 +
 
 +
The chief characters of the anal division in the female are as follow
 +
the aperture of the anus is somewhat nearer the coccyx than in tl
 +
male, the distance between the ischial tuberosities is greater than
 +
the male, and the ischio-rectal fossae are wider and shallower than
 +
the male.
 +
 
 +
Muscles. —The muscles of the female perineum, as compared wil
 +
those of the male, present certain differences.
 +
 
 +
Levatores Ani. —The anterior fibres of these muscles embrace tl
 +
vagina instead of the prostate gland, as in the male.
 +
 
 +
Ischio-cavernosus (Erector Clitoridis). —This muscle replaces tl
 +
ischio-cavernosus of the penis, and is of small size.
 +
 
 +
Bulbo-spongiosus (Sphincter Vaginae). —This muscle arises from tl
 +
perineal body, where it meets the external sphincter and superfici;
 +
transverse perineal muscles. It then passes forwards and divid<
 +
into two symmetrical parts which surround the vaginal orifice an
 +
vestibule, each part closely embracing the outer surface of the corn
 +
sponding bulb of vestibule. Anteriorly the two parts become vei
 +
narrow, and each is inserted into the fibrous sheath of the corpi
 +
spongiosum. A few fibres are here detached to be inserted into
 +
tendinous expansion on the dorsum of the clitoris covering the dors;
 +
vein, which vessel would be thereby compressed when the muscle
 +
in action. Some of the inner fibres of the bulbo-spongiosus are inserte
 +
into the mucous membrane of the vestibule.
 +
 
 +
Sphincter Urethrae. —This muscle, as in the male, lies between tb
 +
two layers of the perineal membrane. It is attached on either sid
 +
to the inner margin of the ischio-pubic ramus, and in the middle lin
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7°3
 +
 
 +
 
 +
: is almost completely divided into two parts by the vagina. The
 +
nterior part passes transversely across the pubic arch in front of the
 +
rethra, whilst the posterior and larger part passes inwards, partly
 +
ransversely and partly obliquely, to blend with the vaginal wall.
 +
 
 +
The external sphincter and superficial transverse perineal muscles
 +
re similar to those in the male.
 +
 
 +
Internal Pudendal Artery. —This vessel is of smaller size than in the
 +
lale, but it takes a similar course. The difference, therefore, in the
 +
wo sexes affects chiefly the branches of the artery.
 +
 
 +
The superficial perineal artery is larger than in the male, and is
 +
istributed to the labium majus.
 +
 
 +
The artery of the bulb is of comparatively small size, and is disributed to the bulb of the vestibule.
 +
 
 +
 
 +
Ischio-cav., on
 +
Crus. Cavernosus
 +
 
 +
Bulbo. Sp. on Bulb
 +
Perineal Membrane
 +
Sup. Trans. Perinei
 +
 
 +
 
 +
Fig. 418. —Ischio-rectal Fossa and Muscles of Female Perineum.
 +
 
 +
The deep artery of the clitoris, having pierced the inferior layer of
 +
fe perineal membrane, enters the crus clitoridis, and is then continued
 +
nwards in the centre of the corpus cavernosum.
 +
 
 +
The dorsal artery of the clitoris, like the preceding, is comparatively
 +
mall in size. Having pierced the inferior layer of the perineal memrane, it passes between the crura clitoridis, and also between the
 +
wo layers of the suspensory ligament of the clitoris. It is then coninued along the dorsum of that organ as far as the glans, having the
 +
orsal vein of the clitoris on its inner side and the dorsal nerve of the
 +
litoris on its outer side. On reaching the glans it divides into branches
 +
Dr the supply of the glans and its prepuce. As it passes along the
 +
orsum of the clitoris it gives off several branches, which enter the
 +
orpus cavernosum by piercing its fibrous sheath.
 +
 
 +
The veins of the female perineum are so similar to those in the male
 +
s not to require any special description. An exception, however, has
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
7 o 4
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
to be made in the case of the dorsal vein of the clitoris. This vein i
 +
formed by branches which return the blood from the glans and pre
 +
puce, and also to a certain extent from the corpora cavernosa. I
 +
passes backwards in the groove between the corpora cavernosa, when
 +
it has on either side of it the dorsal artery, and lateral to this the dorsa
 +
nerve, of the clitoris. In this part of its course it receives tributarie
 +
from the corpora cavernosa. On reaching the root of the organ i
 +
passes between the two layers of the suspensory ligament of the clitoris
 +
and then between the inferior and transverse perineal ligaments, anc
 +
so enters the pelvic cavity, where it terminates in the plexus of vein:
 +
at the neck of the bladder.
 +
 
 +
Lymphatics. —The lymphatics of the vulva, including those of the
 +
prepuce of clitoris, terminate in the superficial inguinal glands , whicf
 +
lie immediately below the inguinal ligament. The lymphatics of the
 +
glans clitoridis, like those of the glans penis, pass to the deep inguinal
 +
and external iliac glands. The lymphatics of the vagina and urethra
 +
run with the vaginal vessels, those of the bulb and corpora cavernosa
 +
clitoridis with the internal pudendal vessels, both sets of lymphatics
 +
terminating in the internal iliac glands.
 +
 
 +
The pudendal nerve and its branches are similar to those in the male,
 +
the superficial perineal nerves being distributed to the labia majora.
 +
 
 +
 
 +
ABDOMINAL WALL.
 +
 
 +
Landmarks. —The position of the linea alba is indicated by the
 +
mid-abdominal groove, which extends from the xiphoid process of the
 +
sternum to the umbilicus, and by the mid-abdominal line, which
 +
extends from the umbilicus to the upper part of the symphysis pubis.
 +
After removal of the skin the linea alba presents a dense white appearance, and is slightly depressed below the level of the adjacent
 +
surfaces. It is produced by the decussation of the aponeuroses of the
 +
abdominal muscles of opposite sides, except the recti, and is divided
 +
into two parts, supra-umbilical and infra-umbilical. The supraumbilical part is about J inch broad, the recti being here separated to
 +
that extent. The infra-umbilical part is only about J inch wide on
 +
account of the approximation of the recti in this situation. Over
 +
the whole extent of its posterior or abdominal surface it is invested by
 +
the parietal peritoneum, unless in cases of abnormal distension of the
 +
bladder, when the peritoneum is stripped from the lower part to an
 +
extent corresponding with the height to which the distended bladder
 +
ascends. The anterior abdominal wall is thinner and less vascular
 +
along the linea alba than at any other part. This line is therefore
 +
selected for such operations as suprapubic lithotomy, tapping a distended bladder above the symphysis pubis, and ovariotomy.
 +
 
 +
The structures which are divided in opening the abdominal cavity along
 +
the linea alba are as follows: the skin, the decussating fibres of the aponeuroses
 +
of opposite sides, fascia transversalis, subperitoneal areolar tissue, and parietal
 +
peritoneum. There are no bloodvessels of any importance in this situation.
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7°5
 +
 
 +
 
 +
The posterior aspect of the linea alba has important visceral rela;ions. The left lobe of the liver lies behind it for about 2 inches below
 +
;he xiphoid process of the sternum. The relation of the stomach to it
 +
s variable. When the viscus is moderately distended it lies behind the
 +
inea alba below the margin of the liver. In the empty condition,
 +
lowever, it recedes from the linea alba, and this gives rise superficially
 +
;o the epigastric depression, or scrobiculus cordis (‘ small trench of the
 +
ieart ’). The transverse colon, covered by the greater omentum, as
 +
t crosses from right to left, usually lies behind the linea alba just above
 +
:he umbilicus. The coils of the jejunum and ileum, also covered by the
 +
greater omentum, lie behind it below the umbilicus.
 +
 
 +
In young persons the upper part of the bladder, being extra-pelvic,
 +
ies behind the lowest part of the linea alba. In adults the upper part
 +
}f that viscus, when abnormally distended, also lies behind the lowest
 +
Dart of this line.
 +
 
 +
The umbilicus takes the form of a cicatricial depression which is
 +
situated in the linea alba at the junction of the upper three-fifths and
 +
ower two-fifths. As seen from the front it is irregularly circular, the
 +
skin being more or less puckered according to the state of distension
 +
Df the abdomen. When viewed from the back it is smaller in size, and
 +
its long measurement lies transversely. Besides cicatricial tissue and
 +
[at, the lower part of it contains the upper ends of the urachus and
 +
Dbliterated hypogastric arteries, whilst the upper part is occupied by
 +
part of the obliterated umbilical vein. The upper part is weaker than
 +
the lower. The umbilicus is on the same horizontal plane as the disc
 +
between the bodies of the third and fourth lumbar vertebrae.
 +
 
 +
In embryonic life there is an opening in the middle line of the
 +
ventral abdominal wall, through which the intra-embryonic and extraembryonic portions of the gut are continuous with one another. The
 +
body-stalk or umbilical cord is attached to the caudal margin of this
 +
opening, extending for a little distance along its sides also, especially
 +
on the left side. When the intestines enter the abdomen, in the
 +
tenth week, the edges of the opening come together, joining medially
 +
in a few days, but the umbilical cord, of course, retains its attachment.
 +
After birth, when the foetal end of the cord sloughs off, the area of its
 +
previous attachment forms a scar, which is the umbilicus. If the
 +
original opening were to persist, it would be in front (above) this scar,
 +
though close to it, and on the right-hand side of the umbilical end of
 +
the ligamentum teres of the liver, the remnant of the left umbilical vein.
 +
 
 +
The linese semilunares (Fig. 419) coincide with the outer borders
 +
of the recti abdominis. The position of each is indicated by a line
 +
drawn from the lowest part of the eighth costal cartilage to the pubic
 +
tubercle. This line is curved, with the convexity outwards, and at
 +
the level of the umbilicus it is about 3 inches from it. Over the upper
 +
three-fourths of the rectus abdominis it indicates the splitting of the
 +
aponeurosis of the internal oblique into two laminae, which encase that
 +
extent of the muscle in a sheath. Over the lower fourth it indicates
 +
where the aponeurosis of the external oblique and part of the aponeurosis
 +
 
 +
45
 +
 
 +
 
 +
 
 +
706
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
of the internal oblique separate from the remainder of the aponeuros
 +
of the internal oblique and the aponeurosis of the transversus, tl
 +
former aponeuroses passing forward in front of the rectus, while ti
 +
latter pass with a curved course downward along the outer edge
 +
the rectus.
 +
 
 +
The substance of the rectus abdominis is traversed by three hoi
 +
zontal tendinous intersections (linea transverse) which cross the recti
 +
in the following situations: one at the level of the umbilicus, one ;
 +
 
 +
 
 +
 
 +
the level of the lower margin of the thorax, and one about miawa;
 +
between these two. The positions of the intersections are indicate*
 +
by three faint grooves. The anterior wall of the sheath of the rectu
 +
is closely bound down to the tendinous intersections, and so each muscf
 +
above the umbilicus is mapped out into quadrangular areas, and th<
 +
interior of the sheath, anterior to the muscle, is also divided int<
 +
distinct compartments. An abscess may form in one or other of thes<
 +
compartments, or there may be a spasmodic contraction of one o
 +
other of these quadrangular areas of the muscle, a condition in eacl
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
707
 +
 
 +
 
 +
case which would necessarily have a circumscribed limit, and might
 +
lead to error in diagnosis.
 +
 
 +
The spino-umbilical lines are two in number, right and left, and
 +
each extends from the anterior superior iliac spine to the umbilicus.
 +
 
 +
The anterior superior spine of the ilium is situated at the anterior
 +
extremity of the iliac crest, and, being very superficial, can be readily
 +
felt. It is on the same level with that of the opposite side, and therefore a line connecting the two should be quite horizontal. The plane
 +
of this interspinous line is rather lower than the promontory of the
 +
sacrum. The anterior superior iliac spine is one of the points from
 +
which the measurement of the lower limb is taken, the other point
 +
being the medial malleolus. This spine is also a good ready guide to
 +
the position of the greater trochanter, which is situated about 4 inches
 +
below it, and about 4J inches behind a line passing vertically through it.
 +
 
 +
The pubic tubercle is situated at the lower and inner part of the
 +
anterior abdominal wall, about ij inches outside the upper part of
 +
the symphysis pubis. It is sometimes a sharp-pointed process, and
 +
then can readily be felt beneath the skin. In most persons, however,
 +
it takes the form of a more or less indistinct tubercle, and cannot
 +
readily be made out. In such cases the scrotal integument may be
 +
invaginated with the finger, and so the adipose tissue raised from over
 +
the spine. If it cannot be felt in this way, the thigh should be well
 +
abducted to render prominent the adductor longus muscle, the tendon
 +
of origin of which will serve as a guide to the spine, which lies above
 +
and to the outer side of it. The pubic tubercle is the guide to the
 +
superficial inguinal ring, the femoral ring, and the saphenous opening.
 +
The superficial inguinal ring is situated immediately above the pubic
 +
tubercle. In exploring the ring, the best way to proceed is to invaginate the scrotal integument, and carry the examining finger up
 +
the inner side of the spermatic cord, when the ring will be reached.
 +
In normal circumstances it should admit the point of the little finger.
 +
In making this examination the spermatic cord is readily felt, and the
 +
vas deferens can be distinguished as a firm cord-like structure lying
 +
posteriorly, and easily separable from the other constituents of the
 +
cord. In the female the ligamentum teres of the uterus takes the place
 +
of the spermatic cord, but, being a very ill-defined structure, it usually
 +
escapes detection. The femoral ring is situated fully 1 inch lateral to
 +
the pubic tubercle in a line drawn transversely outwards from that
 +
spine across the front of the thigh. The saphenous opening is situated
 +
below, and lateral to, the pubic tubercle.
 +
 
 +
The pubic crest extends transversely inwards for about ij inches
 +
from the pubic tubercle, and terminates in the pubic angle, which surmounts the medial surface of the pubic body, and is usually a rudimentary tubercle. The crest may be felt with the finger as the superficial inguinal ring, of which it forms the base, is being explored.
 +
 
 +
The inguinal ligament can be felt as a tense band, especially when
 +
the thigh is extended, abducted, and rotated outwards, passing between
 +
the anterior superior iliac spine and the pubic tubercle.
 +
 
 +
 
 +
708
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
The deep inguinal ring is situated inch above the mid-point o
 +
the inguinal ligament.
 +
 
 +
The inguinal canal extends for i-| inches obliquely downwards
 +
forwards, and inwards from the deep to the superficial inguinal ring
 +
and is situated immediately above the inner half of the inguina
 +
ligament.
 +
 
 +
Topography of Arteries, Triangles, and Iliac Fossae. —The bifur
 +
cation of the aorta into right and left common iliac arteries usualh
 +
takes place opposite the centre of the body of the fourth lumba
 +
vertebra, a finger’s breadth to the left of the middle line. The positioi
 +
of the bifurcation is indicated in one of two ways: (i) a point J incl
 +
below and to the left of the umbilicus; (2) a more definite guide is ;
 +
point in the line which connects the highest parts of the iliac crest:
 +
a finger’s breadth to the left of where it intersects the linea alba.
 +
 
 +
The common and external iliac arteries are indicated by a line
 +
drawn from a point midway between the anterior superior iliac spine
 +
and the symphysis pubis to the point corresponding to the bifurcatior
 +
of the aorta. This line should be slightly curved, with the convexity
 +
directed outwards. Its upper 2 inches indicate the course of the
 +
common iliac artery, and the remainder represents the external
 +
iliac.
 +
 
 +
The inferior epigastric artery, in its first or oblique part, is indicated
 +
by a line drawn from the inner border of the deep inguinal ring to the
 +
outer border of the rectus abdominis at a point midway between the
 +
upper border of the symphysis pubis and the umbilicus. The subsequent course of the vessel is represented by a line corresponding to the
 +
centre of the rectus abdominis, and reaching to a point about 2 inches
 +
above the umbilicus. This latter line is about ij inches distant from
 +
the linea alba.
 +
 
 +
I he inguinal triangle (Hesselbach’s) is situated on the inner side
 +
of the first or oblique part of the inferior epigastric artery, and above
 +
the inner half of the inguinal ligament.
 +
 
 +
The lumbar triangle (of Petit) is situated immediately above the
 +
centre of the iliac crest. In this region a lumbar hernia may protrude,
 +
and a lumbar abscess may here come to the surface.
 +
 
 +
The right iliac fossa contains the terminal part of the ileum, the
 +
caecum, the vermiform appendix, and beginning of the ascending
 +
colon.
 +
 
 +
I he left iliac fossa contains the iliac part of the descending colon.
 +
 
 +
McBurney’s point is situated in the right spino-umbilical line between _i J and 2 inches from the anterior superior iliac spine. According
 +
to McBurney, it corresponds very accurately in the living subject to
 +
the base of the vermiform appendix. Practically it coincides with the
 +
centre of the right iliac fossa. The point is now regarded as indicating
 +
approximately the situation of the ileo-colic valve, and not the base
 +
of the vermiform appendix. The guide to the base or opening of the
 +
 
 +
appendix is a point on an average rather more than 1 inch below the
 +
ileo-colic valve.
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7 ° 9
 +
 
 +
 
 +
Anterior Abdominal Fasciae. —The superficial fascia of the anterior
 +
vail of the abdomen, from the inguinal ligament to a line drawn transversely from the anterior superior iliac spine to the linea alba, resembles
 +
he superficial fascia of the uro-genital division of the perineum in
 +
)eing divisible into two layers. The layer immediately beneath the
 +
kin is called the fatty superficial layer, and the other layer is called
 +
he deeper membranous layer.
 +
 
 +
The fatty superficial layer (fascia of Camper) is composed of areolar
 +
issue containing adipose tissue in its meshes. When traced upwards,
 +
t blends with the deep layer above the level of the line connecting the
 +
.nterior superior iliac spine with the linea alba. When followed inwards, it is continuous with the corresponding layer of the opposite
 +
ide. In a downward direction it is freely continuous over the inguinal
 +
igament with the superficial layer of the superficial fascia of the
 +
ront of the thigh. When traced downwards and inwards, it passes
 +
long the spermatic cord into the scrotal wall and over the penis, in
 +
vhich situations, more especially the former, it contains involuntary
 +
nuscular fibres, which replace its adipose tissue, and so, with the deep
 +
ayer which it here joins, it forms the dartos muscle. In the female,
 +
he fatty superficial fascia passes along the ligamentum teres of the
 +
items into the labium majus.
 +
 
 +
The deeper membranous layer (fascia of Scarpa) is a strong membrane which contains yellow elastic tissue. It is separated from the
 +
uperficial layer by the superficial epigastric vessels, and in the region
 +
f the inguinal ligament by the inguinal glands. Its deep aspect is
 +
aosely connected by areolar tissue to the subjacent aponeurosis of
 +
he external oblique muscle. Superiorly, above the line connecting
 +
he anterior superior iliac spine with the linea alba, it blends with
 +
uperficial layer. At the middle line it is firmly bound down by fibrous
 +
•ands to the linea alba. Interiorly it blends medially with the inguinal
 +
gament, but laterally it passes over that ligament for a distance of
 +
n inch or so, and then becomes incorporated with the fascia lata of
 +
he thigh. When traced downwards and inwards, it passes along the
 +
permatic cord into the scrotal wall and over the penis. In the former
 +
ituation it forms, along with the superficial layer, the dartos muscle.
 +
n the female, the deeper layer passes along the ligamentum teres of
 +
he uterus into the labium majus.
 +
 
 +
The superficial layer is continuous through the dartos muscle with
 +
he superficial layer of the superficial fascia of the uro-genital division
 +
f the perineum, and the deeper layer is similarly continuous with the
 +
eep layer of the superficial fascia. In the middle line the deeper layer
 +
5 continued down in the form of a collection of fibres which, separating
 +
ito two bundles, pass on either side of the penis to blend with the
 +
heath. To these fibres the term superficial suspensory ligament of
 +
he penis has been applied.
 +
 
 +
The disposition of the deeper membranous layer at the line of the
 +
rom explains why, in cases of extravasation of urine beneath the deep
 +
l yer of superficial perineal fascia, the urine, when it reaches the
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
710
 +
 
 +
anterior abdominal wall, does not pass downwards to the front of th
 +
thigh, but takes an upward course.
 +
 
 +
The deeper layer of superficial fascia represents the tunica abdominalis c
 +
quadrupeds, which is composed almost entirely of elastic tissue, and serves as a
 +
important adjunct to the abdominal parietes.
 +
 
 +
The separation, entirely artificial, of the superficial fascia int
 +
a superficial fatty layer and a deep membranous layer, the so-calle*
 +
deep fascia, obtains "throughout the body, but in the lower part c
 +
the anterior abdominal wall is more apparent than elsewhere. Th
 +
reasons are (1) the frequent accumulation of fat in this region makin
 +
the superficial layer very distinct; (2) the presence in considerabl
 +
abundance of strong fibres, some of which are said to be elastic, ii
 +
the deep layer, accentuating its membranous character; (3) the exist
 +
ence beneath the deep layer of an aponeurosis, and the consequen
 +
tendency for the formation of a membranous covering. While else
 +
where the two layers are named superficial and deep fascia respectively
 +
it is customary in the region of the anterior abdominal wall for historica
 +
reasons to speak of both layers as forming the superficial fascia, and t<
 +
make no reference to any deep fascia.
 +
 
 +
Cutaneous Nerves. —The anterior cutaneous nerves are the termina
 +
branches of the lower five intercostal nerves and of the anterior primar
 +
division of the twelfth thoracic nerve (subcostal nerve). Having
 +
emerged through the anterior wall of the sheath of the rectus abdomini
 +
in a straggling manner, they give a few twigs inwards, and then turi
 +
outwards to supply the anterior abdominal integument, in which the>
 +
communicate with the anterior branches of the lateral cutaneous nerves
 +
The" nerves pursue a tortuous course, and are therefore not so subjec
 +
to strain during the movements of the anterior abdominal wall as the^
 +
would be if their course were straight.
 +
 
 +
The anterior cutaneous branch of ilio-hypogastric nerve pierces th<
 +
external oblique aponeurosis about 1 inch above the superficial inguina
 +
ring, and is distributed to the skin of the suprapubic region. It i‘
 +
serially continuous with the anterior cutaneous nerves.
 +
 
 +
The skin below the xiphoid process is supplied by the seventh thoracic nerve
 +
that on a level with the umbilicus by the tenth thoracic; and that over the lowe:
 +
half of the infra umbilical region by the subcostal and the ilio-hypogastric.
 +
 
 +
The lateral cutaneous nerves are branches of the lower five inter
 +
costal nerves. Having emerged between the digitations of the externa
 +
oblique muscle in the mid-axillary line, each divides into an anterio]
 +
and a posterior branch. The posterior branch turns backwards tc
 +
supply the skin over the lower part of the back. The anterior brand
 +
passes forwards to supply the skin of the anterior abdominal wall
 +
communicating with an anterior cutaneous nerve.
 +
 
 +
Cutaneous Arteries.— The superficial external pudendal artery arises from the
 +
femoral about f inch below the inguinal ligament, after which it pierces the
 +
femoral sheath and cribriform fascia. Having emerged through the saphenous
 +
opening, it passes inwards and upwards over the spermatic cord or ligamentun
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
711
 +
 
 +
sres of the uterus, according to the sex, to be distributed to the skin of the
 +
uprapubic region, the adjacent portion of the scrotum in the male and the
 +
ibium majus in the female, and the dorsum of the penis by a branch which
 +
xtends as far as the prepuce, lying lateral to the dorsal artery of penis. The
 +
essel in its course gives branches to the inguinal glands, and the covering of
 +
he spermatic cord, or of the ligamentum teres of the uterus. It anastomoses
 +
nth the following arteries: (a) the cremasteric branch of the inferior epigastric,
 +
 
 +
 
 +
 
 +
Fig. 420. —Cutaneous Nerves of the Trunk (Antero-lateral
 +
 
 +
View) (after Henle).
 +
 
 +
1-12, anterior cutaneous; 2-12, lateral cutaneous.
 +
 
 +
 
 +
Jr in the female the artery to the ligamentum teres of the uterus; (b) its fellow
 +
}f the opposite side; (c) the deep external pudendal; (d) the superficial perineal;
 +
md (e) the dorsal artery of penis.
 +
 
 +
The venae comites of this artery terminate in one vessel, which joins the long
 +
■saphenous vein.
 +
 
 +
The superficial epigastric artery arises from the femoral about | inch below
 +
the inguinal ligament. Having pierced the femoral sheath and cribriform fascia,
 +
3r the outer border of the saphenous opening, it turns upwards over the inguinal
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
712
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
ligament a little to the inner side of the centre, and then ascends as high as t
 +
level of the umbilicus. As it turns upwards it supplies branches to the supe
 +
ficial inguinal glands, and on the abdominal wall anastomoses with branches
 +
the inferior epigastric artery.
 +
 
 +
There are at first two venae comites with this artery, but these eventual
 +
join to form one vessel which terminates in the long saphenous vein. T\
 +
radicles of these venae comites communicate with the following vessels: the par
 +
umbilical veins in the region of the umbilicus, which lie on the surface of t]
 +
ligamentum teres of the liver, and communicate with the branches of the vei
 +
portae; the lateral thoracic and subscapular veins, upon the side of the thora
 +
which are tributaries of the axillary vein; and the superior epigastric veir
 +
which are tributaries of the internal mammary veins. In the superficial epigastr
 +
vein and its tributaries the blood can flow in either direction. In cases of port
 +
obstruction the venous anastomoses in the neighbourhood of the umbilicus u
 +
infrequently become engorged, resulting in a system of subcutaneous vei]
 +
radiating from the umbilicus and known as the Caput Medusce.
 +
 
 +
The superficial circumflex iliac artery often arises in common with the supe
 +
ficial epigastric from the femoral about inch below the inguinal ligamen
 +
Having pierced the fascia lata on the outer side of the saphenous opening,
 +
passes outwards below the outer part of the inguinal ligament to the anteri<
 +
part of the iliac crest, where it is distributed to the adjacent abdominal integi
 +
ment. In its course it gives branches to the iliacus and sartorius muscles ar
 +
the outer inguinal glands, and it anastomoses with (a) the deep circumflex ilk
 +
of the external iliac, and (b ) the superior gluteal of the internal iliac.
 +
 
 +
The vein corresponding to this artery terminates in the long saphenous veil
 +
 
 +
The anterior cutaneous arteries are derived from the inferior and superb
 +
epigastric arteries. They emerge through the anterior wall of the sheath of tl
 +
rectus abdominis in an irregular manner, and accompany more or less close]
 +
the anterior cutaneous nerves.
 +
 
 +
The veins corresponding to these arteries terminate in the inferior and superb
 +
epigastric veins.
 +
 
 +
The lateral cutaneous arteries are branches of the lower five posterior inte
 +
costal and subcostal arteries, and they emerge with the lateral cutaneous nerv
 +
between the digitations of the external oblique muscle in the mid-axillary line
 +
 
 +
The veins corresponding to these arteries are tributaries of the lower frv
 +
posterior intercostal and subcostal veins.
 +
 
 +
Superficial Lymphatics. —The superficial lymphatics below the lev<
 +
of the umbilicus accompany the superficial epigastric vessels, an
 +
terminate in the superficial inguinal glands. Those above the lev(
 +
of the umbilicus pass to the axillary glands. The superficial lymphatic
 +
of the lateral abdominal wall terminate in two ways. Some accompan
 +
the superficial circumflex iliac vessels, and terminate in the superfick
 +
inguinal glands; others accompany the abdominal branches of th
 +
lumbar arteries, and terminate in the deeply-placed aortic group c
 +
lumbar glands. For the deep lymphatics of the antero-latera .1 at
 +
dominal wall, see p. 733.
 +
 
 +
Penis—Coverings. —The skin at the free extremity of the glam
 +
being doubled upon itself, passes backwards until it reaches the cor
 +
striction behind the corona glandis called the neck. Here it is reflecte*
 +
forwards, closely investing the neck, corona glandis, and body of th
 +
glans. On reaching the lips of the external orifice of urethra it become
 +
continuous with the mucous membrane of the urethra. The ski]
 +
covering the glans is provided with papillae, but these do not appea
 +
on the surface, The duplicature, which the skin forms in the regio]
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7 i 3
 +
 
 +
 
 +
the glans, is called the prepuce. The under part of the prepuce
 +
connected to the under surface of the glans by a median, laterally
 +
npressed, triangular fold, called the frenulum, which extends as far
 +
the lower part of the external orifice of urethra. Sebaceous glands
 +
ve been described by Kolliker as present on the inner surface of the
 +
ipuce, particularly in the region of the frenulum, and less constantly
 +
the glans and at the corona. Glands in these regions were first
 +
ted by Tyson in the orang, and are sometimes in consequence named
 +
er him. Whether they exist in man or not is a matter of some doubt;
 +
•tain histologists do not hesitate to deny their presence, and attribute
 +
3 so-called secretion under the prepuce—the smegma preputii —to the
 +
making down of desquamated epithelial cells. The dartos muscle is
 +
uated immediately beneath the skin, and is destitute of adipose
 +
sue. It is continuous with fatty superficial and deeper membranous
 +
 
 +
Superficial Dorsal Vein
 +
(Deep) Dorsal Vein
 +
Dorsal Artery
 +
Dorsal Nerve
 +
 
 +
Corpus Cavernosum Penis
 +
Artery of Corp. Cav. Penis
 +
Fascial Sheath
 +
 
 +
Corpus Spongiosum
 +
Urethra
 +
 
 +
Artery of Corp. Spong.
 +
 
 +
 
 +
 
 +
Fig. 421.—Diagram of Section across the Penis (Enlarged).
 +
 
 +
/ers of the fascia of the anterior abdominal wall, and with the dartos
 +
iscle of the scrotum, like which latter it contains involuntary muscular
 +
•sue. The fascial investment or sheath is rich in elastic fibres, and
 +
vers the penis, with the exception of the glans. It is situated beneath
 +
e dartos muscle, from which it is separated by loose areolar tissue,
 +
id at the neck blends with the skin of the glans. Towards the root
 +
the organ it receives expansions from the ischio-cavernosus and
 +
ilbo-spongiosum muscles, and covers the dorsal vessels and nerves.
 +
 
 +
* this way the dorsal vein is compressed during the action of these,
 +
t the root of the organ the fascial investment blends with the two
 +
Vers of the suspensory ligament.
 +
 
 +
Suspensory Ligament. —This ligament, sometimes called the deep
 +
-spensory ligament, is strong and triangular in outline, and is combed of fibrous and elastic tissues. It is attached superiorly to the
 +
ont of the symphysis pubis, where it is single, and inferiorly it divides
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
7 M
 +
 
 +
into two laterally-disposed, diverging laminae, which blend with t
 +
fascial sheath of the penis. The interval between the two laminae
 +
occupied by the dorsal vessels and nerves. The ligament is part
 +
formed from fibres continued into it from the aponeurosis of t
 +
external oblique muscle.
 +
 
 +
The Dorsal Arteries. —For the description of these arteries, s
 +
 
 +
p. 688.
 +
 
 +
In addition to the dorsal artery, the skin of the organ is suppli<
 +
by the superficial external pudendal arteries, the branch from each
 +
these vessels lying lateral to the dorsal artery or penis.
 +
 
 +
Deep Dorsal Vein. —The tributaries which give rise to this ve
 +
come from the glans and corpora cavernosa. They form at first tv
 +
dorsal veins, but these soon unite into one vessel, which passes bac'
 +
wards in the middle line, occupying the groove between the corpo:
 +
cavernosa, where it is under cover of the fascial sheath of the pem
 +
At the root of the organ it passes between the two laminae of the su
 +
pensory ligament, and then between the inferior and transverse perine
 +
ligaments. In this part of its course it communicates with the venoi
 +
plexus in the sphincter urethrae muscle in which the internal pudend
 +
venae comites arise. On entering the pelvis it divides into two branche
 +
 
 +
which terminate in the right ar
 +
left portions of the prostat
 +
plexus of veins.
 +
 
 +
In addition to the deep dors
 +
vein, there are two superficial dors
 +
veins which take up blood from tl
 +
glans and skin. Each accompani
 +
a branch of the superficial extern
 +
pudendal artery, and opens into tl
 +
superficial external pudendal vein
 +
 
 +
For a description of tl
 +
dorsal nerves of the penis, sf
 +
p. 689.
 +
 
 +
The relation of the stru<
 +
tures on the dorsum of the peni
 +
from the middle line outward
 +
is as follows: deep dorsal veil
 +
dorsal artery, and dorsal nerv
 +
Composition of the Penis.The penis has two surfacesupper or dorsal, and under c
 +
scrotal. Viewed as a who!
 +
the organ is composed of thrf
 +
cylindrical bodies—namely, tw
 +
corpora cavernosa and a corpi
 +
spongiosum—closely applied t
 +
each other. It is divisible int
 +
a root, body, neck, and glans. The root is formed by the crura (
 +
the corpora cavernosa, which are attached to the inner margins (
 +
 
 +
 
 +
 
 +
Fig. 422.—Plans to show Structure
 +
of Penis.
 +
 
 +
A, ventral aspect; B, lateral; C, terminal,
 +
showing glans covering the ends of corp.
 +
cav. penis ; CCP, corp. cav. penis ;
 +
CCU, corp. spongiosum ; GL, glans ;
 +
susp., suspensory ligament.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7 i 5
 +
 
 +
 
 +
3 ischio-pubic rami. The upper surface of the root is also connected
 +
the symphysis pubis by the suspensory ligament. The upper or
 +
rsal surface of the body is formed by the corpora cavernosa, the
 +
der or scrotal surface being formed by the corpus spongiosum in the
 +
ddle line and the corpora cavernosa at either side. The corpora
 +
/ernosa and corpus spongiosum at their meeting become flattened,
 +
d so the shape of the body is subcylindrical. The corpora cavernosa
 +
minate in round extremities, in front of which the corpus spongiosum
 +
rns upwards, and, becoming much enlarged, forms the glans penis.
 +
ie neck is the constriction between the body and the glans. The
 +
ins penis is formed by the corpus spongiosum. It is somewhat
 +
tiical, and has been likened to an acorn, from which circumstance it
 +
s been called the balanus. At the base there is a wheel-like rim,
 +
Lied the corona glandis. The part anterior to the corona is called
 +
3 body of the glans, and presents anteriorly a vertical fissure
 +
Lied the external orifice of urethra. For the structure of the penis,
 +
i p. 682.
 +
 
 +
Lymphatics. —These are divided into a superficial and deep set.
 +
The lymphatics of the prepuce form a finely meshed plexus which
 +
the region of the corona communicates with the lymphatics of the
 +
ms. The collecting trunks from the plexus pass backwards, forming
 +
single median vessel, double bilateral, or more frequently multiple
 +
ssels, which run on the dorsum of the penis and receive as they go
 +
butary lymphatic vessels from the suprathecal portion of the penis.
 +
1 reaching the symphysis the vessels turn some to the right, others
 +
the left—a single vessel dividing—and running immediately under
 +
e skin terminate in the superficial inguinal glands. Owing to the
 +
ie anastomosis which exists between the vessels, the glands of either
 +
le may become infected from a septic focus on one side.
 +
 
 +
The lymphatics of the glans form a very finely meshed plexus,
 +
e collecting trunks from which pass downwards, at the side of the
 +
3 nulum, and then, after communicating with the lymphatics of the
 +
epuce and the anterior part of the urethra, pass dorsally surrounding
 +
e corona glandis, after which they run backwards along the dorsum
 +
irallel with those from the prepuce, but lying deep to, instead of
 +
perficial to, the sheath of the penis, receiving in their course tributary
 +
mphatics from the intrathecal portion of the penis. On reaching the
 +
mphysis they form a plexus in which occasionally small presymphysial
 +
mph nodules are to be found, and then pass outwards either to the
 +
:e P inguinal glands or through the femoral and inguinal canals to the
 +
ands forming the medial and lateral chains respectively of the external
 +
ac glands.
 +
 
 +
The lymphatics of the clitoris correspond with those of the penis.
 +
Scrotum. —The wall of the scrotum is complex, and its constituent
 +
irts will be made more evident if they are enumerated in the order
 +
which the testes receive them in their original descent from the
 +
)dommal cavity. It may be premised that the descent of each
 +
stis is preceded by a process of peritoneum, called the processus
 +
 
 +
 
 +
 
 +
716
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
vaginalis, the lower part of which remains permanent as the tun
 +
vaginalis testis, the upper part becoming obliterated, and be:
 +
normally represented in the adult, if at all, by a fibrous cord. 1
 +
constituent parts of the scrotal wall, enumerated from within outwar
 +
are as follows: tunica vaginalis testis, subperitoneal areolar tiss
 +
internal spermatic fascia, cremasteric muscle and fascia, exter:
 +
spermatic fascia, dartos muscle, and skin.
 +
 
 +
 
 +
 
 +
Fig. 423.—Plan of Structure
 +
of Scrotal Walls.
 +
 
 +
TV, tunica vaginalis; C, cord;
 +
T, testis. The coverings, deep
 +
to the corrugated skin, are
 +
(1) external spermatic fascia
 +
(from external oblique) shown
 +
by a fine line; (2) dotted line,
 +
cremasteric fascia from internal oblique; (3) interrupted
 +
line, internal spermatic fascia
 +
from trailsversalis fascia.
 +
 
 +
 
 +
The tunica vaginalis testis is the park
 +
 
 +
layer of the tunica vaginalis.
 +
 
 +
The subperitoneal areolar tissue is compo
 +
of areolar and adipose tissues, and a cert
 +
amount of plain muscular tissue.
 +
 
 +
The internal spermatic fascia is derh
 +
from the fascia transversalis at the margin'
 +
the deep inguinal ring, in which vicinity il
 +
called the infundibuliform fascia. In assoc
 +
tion with the subperitoneal areolar tissue
 +
forms the fascia propria of Cooper.
 +
 
 +
The cremasteric fascia is composed
 +
striated muscular tissue, forming the cremas
 +
muscle, and of areolar and elastic tissues,
 +
is traceable superiorly to the lower border
 +
the internal oblique, the deep surface of 1
 +
inguinal ligament, and the pubic tubercle.
 +
 
 +
The external spermatic fascia is compos
 +
of connective tissue, and is derived from t
 +
intercrural fibres which extend between t
 +
columns of the superficial inguinal ring. T
 +
above three layers of fasciae are so closely :
 +
corporated as to be indistinguishable frc
 +
one another.
 +
 
 +
The dartos muscle lies immediately with
 +
the skin. It is derived from the fatty sup(
 +
ficial and deeper membranous layers of t
 +
fascia of the anterior abdominal wall. It
 +
chiefly composed of plain muscular tissue, b
 +
it also contains fibro-areolar and elastic tissue
 +
and it has a brick-red colour.
 +
 
 +
The skin is thin, very extensible, dark
 +
colour, and provided with hairs, sweat-gland
 +
and sebaceous glands. It is more depende:
 +
on the left side on account of the low
 +
position of the left testis. In the middle lii
 +
it presents a raphe,which is continuous behir
 +
with that of the anterior part of the perineur
 +
 
 +
 
 +
and in front with that on the under surface
 +
the penis. This raphe is an external indication of the bilateral symmetry
 +
the scrotum. On either side of the raphe the skin is thrown into a number
 +
transverse rugae, the corrugated condition being due to the plain muscular tiss
 +
of the dartos muscle.
 +
 
 +
 
 +
The interior of the scrotum is divided into two compartments
 +
each of which lodges the corresponding testis. This division is effecte
 +
by the scrotal septum, formed by the fusion of the contiguous walls c
 +
the two scrotal chambers, except the skin, which forms one continuou
 +
investment to both. Interiorly the septum is attached to the botton
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
717
 +
 
 +
 
 +
he scrotal chamber and superiorly to the under surface of the root
 +
he penis.
 +
 
 +
Blood-supply. —The scrotum receives its chief arterial supply from
 +
superficial and deep external pudendal branches of the femoral of
 +
h side, and the superficial perineal branches of the internal pudendal
 +
3ries.
 +
 
 +
The veins corresponding to these arteries terminate in the long
 +
henous and internal pudendal veins.
 +
 
 +
The cremasteric branch of the inferior epigastric of each side also
 +
es part in the supply of the scrotal wall, the venous blood being
 +
irned into the inferior epigastric vein, which at its termination is
 +
lie.
 +
 
 +
Lymphatics. —The lymphatics of the scrotum are divided into a
 +
erior and an inferior set. They pass upwards and outwards to
 +
ninate in the superior and inferior groups respectively of the superil inguinal glands.
 +
 
 +
Nerve-supply. —The nerves of the scrotum are as follows: (1) the
 +
;ral and medial posterior scrotal branches of the pudendal; (2) the
 +
y perineal nerve from the posterior cutaneous nerve of thigh;
 +
the ilio-inguinal from the lumbar plexus; and (4) twigs of the
 +
ital branch of the genito-femoral nerve from the lumbar plexus.
 +
Development. —The genital swellings.
 +
 
 +
Muscles of Abdominal Wall—Obliquus Externus Abdominis— Origin.
 +
'he outer surfaces of the lower eight ribs by means of eight flesh) 7
 +
s, the upper five of which interdigitate with slips of the serratus
 +
erior, and the lower three with slips of the latissimus dorsi.
 +
Insertion. —fi) The anterior half of the outer lip of the iliac crest
 +
fleshy fibres. (2) By means of an aponeurosis into (a) the linea
 +
a, and so into the xiphoid cartilage and symphysis pubis; (b) the
 +
>ic tubercle and crest of the opposite side by means of the reflected
 +
t of inguinal ligament; (c) the pubic tubercle and anterior superior
 +
2 spine of the same side by means of the inguinal ligament; and
 +
the first inch of the pectineal line by means of the pectineal part
 +
;he inguinal ligament.
 +
 
 +
Nerve-supply .—The lower five intercostal nerves and the subcostal
 +
 
 +
ve.
 +
 
 +
Action. —(1) The two muscles, acting conjointly, diminish the size of the
 +
ominal cavity, and so compress the viscera, as in defaecation. (2) The two
 +
ides, acting conjointly from their origins, raise the front part of the pelvis
 +
flex it upon the thorax. (3) Acting conjointly from their insertions, they
 +
the thorax upon the pelvis, the vertebral column being also flexed in the
 +
er thoracic and lumbar regions; but, if the column is fixed, the two muscles
 +
ress the lower eight ribs. (4) One muscle, acting from its origin, is a lateral
 +
or of the pelvis. When it acts from its insertion it flexes the thorax towards
 +
)wn side and rotates it to the opposite side.
 +
 
 +
Most of the fibres of the external oblique pass downwards and
 +
wards, coinciding in direction with those of the external intercostal
 +
scles. The only parts of the muscle which are free are the part
 +
 
 +
 
 +
718
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
between the last rib and the iliac crest, and the part opposite the pc
 +
crest. The aponeurosis attains its greatest width and strength
 +
and below, the level of the anterior superior iliac spine, and ii
 +
narrowest opposite the umbilicus. Superiorly it gives origin to fit
 +
of the pectoralis major. Crossing the fibres of the aponeurosis in
 +
upward and inward direction there are several superadded fibres,
 +
the lower part of the abdominal wall these are specially well mark
 +
 
 +
 
 +
Pectoralis Major
 +
 
 +
 
 +
Serratus Anterior _
 +
 
 +
 
 +
Latissimus Dorsi
 +
 
 +
Obliquus Externus
 +
Abdominis
 +
 
 +
 
 +
Lumbar Triangle
 +
 
 +
 
 +
 
 +
Middle Tendinous
 +
, l|u i Intersection
 +
 
 +
 
 +
^.-Umbilicus
 +
 
 +
 
 +
_Rectus Abdominis
 +
 
 +
 
 +
_.Anterior Superior
 +
 
 +
Iliac Spine
 +
 
 +
 
 +
.Inguinal Ligament
 +
 
 +
 
 +
Spermatic Cord at
 +
4 jri- Superficial Inguinal
 +
Ring
 +
 
 +
 
 +
Fig. 424.—The External Oblique Muscle.
 +
 
 +
 
 +
and are here spoken of as the inter crural fibres. Under this nai
 +
they spring from the outer third of the inguinal ligament, whence th
 +
pass upwards and inwards in a curved manner, the convexity bei
 +
downwards. On arriving at the upper and outer part of the superfic
 +
inguinal ring they extend from one column to the other. They rou
 +
off and close the ring, and are prolonged upon the spermatic cord
 +
form the external spermatic fascia.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
710
 +
 
 +
The following parts of the external oblique aponeurosis require
 +
cial description: inguinal ligament, pectineal part of inguinal ligaat, the reflected part of inguinal ligament, the superficial inguinal
 +
y, and the linea alba.
 +
 
 +
Inguinal ligament (Poupart’s) is the thickened lower border of the
 +
ernal oblique aponeurosis, which is folded backwards. Laterally
 +
s attached to the anterior superior iliac spine, and medially to the
 +
)ic tubercle, from which it is reflected outwards and backwards
 +
>n the pectineal line for fully 1 inch to form its pectineal part. The
 +
iment is curved, the convexity being directed downwards and outrds, due to the attachment of the iliac lamina of the fascia lata to its
 +
'er border. The convexity is greatest when the thigh is extended,
 +
lucted, and rotated outwards, in which position the fascia lata on
 +
front of the thigh is tightened.
 +
 
 +
Relations — Superficial. —Skin; the superhcial and deeper layers of the fascia
 +
he anterior abdominal wall; superficial epigastric vessels, a little to the inner
 +
! of the centre; superficial circumflex iliac vessels just below its outer part; and
 +
superficial inguinal glands along its lower border. Deep .—Internal oblique,
 +
lsversus abdominis, and cremaster muscles, which take part of their origin
 +
n its deep surface; the ilio-psoas and pectineus; the fascia transversalis and
 +
:ia iliaca, which are attached to its lateral portion, forming a canal containing
 +
deep circumflex iliac vessels; the fascia transversalis, forming the anterior
 +
1 of the femoral sheath; the deep femoral arch, femoral vessels, deep inguinal
 +
ids, and lymphatic vessels; the femoral and genito-femoral nerves, and the
 +
:ral cutaneous nerve of thigh.
 +
 
 +
The deep femoral arch is a thickening of the fascia transversalis as it passes
 +
mwards beneath the inguinal ligament to form the anterior wall of the femoral
 +
ith. The thickening is due to superadded fibres which extend inwards from
 +
centre of the inguinal ligament on its deep aspect to the pectineal line, where
 +
y are attached behind its pectineal part near its base.
 +
 
 +
The pectineal part of inguinal ligament (Gimbernat’s) is the reflection
 +
:he inguinal ligament from the pubic tubercle along the pectineal line,
 +
length is fully 1 inch, and it is triangular, the apex being at the
 +
:>ic tubercle. It presents three borders and two surfaces. Two of
 +
! borders are fixed, one, called the inguinal border, being continuous
 +
:h the inner end of the inguinal ligament, and the other, called the
 +
tineal border, being implanted on the pectineal line. The third
 +
~der is free, and is called the base. It is sharp, wiry, and concave,
 +
I is situated immediately to the inner side of the femoial ring. The
 +
'faces of the ligament are femoral and abdominal. They occupy
 +
oblique plane, the femoral surface looking downwards, forwards, and
 +
?htly outwards, whilst the abdominal surface looks upwards, backrds, and slightly inwards. This latter surface, along its line of juncn with the inguinal ligament, forms the floor of the inguinal canal in
 +
lower third, where it supports the spermatic cord in the male, and
 +
* ligamentum teres of the uterus in the female. The fascia transrsalis is attached to the base of the ligament on its abdominal
 +
}ect, and the conjoint tendon and fascia transversalis lie behind it
 +
the pectineal line. A few of the fibres of the superior cornu of the
 +
dienous opening terminate on the femoral surface of the ligament,
 +
 
 +
 
 +
720
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
and the pectineus muscle and pubic lamina of the fascia lata are
 +
front of its pectineal attachment.
 +
 
 +
The reflected part of inguinal ligament (triangular fascia), also knov
 +
as the ligament of Colies, is situated behind the spermatic cord ar
 +
superior crus of the superficial inguinal ring. Its fibres are derive
 +
from the external oblique aponeurosis of the opposite side; havir
 +
crossed the linea alba, they gain insertion into the pubic tubercle ar
 +
 
 +
 
 +
 
 +
Fig. 425. —Anterior View of Muscles and Aponeuroses.
 +
 
 +
External oblique removed on one side to expose the internal oblique. Termini
 +
cutaneous branches of nerves shown on one side, coming through sheat
 +
of rectus.
 +
 
 +
crest. A portion of the fascia is seen lying in the lower and inner par
 +
of the superficial inguinal ring.
 +
 
 +
The superficial inguinal (external abdominal) ring is an opening fi
 +
the aponeurosis of the external oblique, and is situated immediately
 +
above the pubic tubercle. It serves for the passage of the spermatf
 +
cord in the male, and the ligamentum teres of the uterus in the female
 +
In the natural condition no opening is perceptible, the intercrura
 +
fibres rounding it off, and being prolonged downwards upon the trans
 +
mitted structure. When the intercrural fibres and fascia have beer
 +
removed, the ring is seen to be formed in the following manner: the
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
721
 +
 
 +
 
 +
Dres of the external oblique aponeurosis, as they approach the os
 +
ibis, are disposed in two diverging bundles. One bundle, which
 +
presents the inner end of the inguinal ligament, is fixed to the pubic
 +
ibercle. The other bundle passes to be attached to the front of the
 +
unphysis pubis, where its fibres decussate with those of its fellow
 +
: the opposite side, the fibres from the right side being superficially
 +
laced. An interval is thus left between these diverging bundles,
 +
hich is widest at the lower and inner part, where it corresponds with
 +
 
 +
Pectoralis Major
 +
 
 +
 
 +
 
 +
i portion of the pubic crest. This interval is the superficial inguinal
 +
■ing. Its direction is upwards and outwards, and it is parallel with
 +
-he inner part of the inguinal ligament. Its length is from 1 inch to
 +
£2 inches, and its breadth at the base about J inch. It is triangular,
 +
the base being formed by part of the pubic crest, and the apex being
 +
directed upwards and outwards. The margins of the ring are called
 +
the crura. From the oblique position of the ring one crus is lateral
 +
and inferior, the other being medial and superior. The superior crus,
 +
which is thin and straight, passes to be attached to the front of the
 +
 
 +
46
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
722
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
symphysis pubis. The inferior crus is at first thin, but it soon becomes
 +
thick and prismatic, and is fixed to the pubic tubercle. It presents
 +
superiorly a concavity which lodges the spermatic cord in the male
 +
and the ligamentum teres of the uterus in the female. The external
 +
spermatic fascia is attached to both crura, lying upon the spermatic
 +
cord. Certain of the lower intercrural fibres are directed with their
 +
concavity downwards, and, passing beneath the cord, serve to round
 +
off the lateral margins of the ring. The presence of the fascia
 +
explains why urine, extravasated into the perineum, does not find its
 +
way into the inguinal canal. Within the lower and inner part of the
 +
ring is the reflected part of inguinal ligament, and directly behind the
 +
ring is the conjoint tendon, which strengthens what would otherwise
 +
be a weak part of the abdominal wall. The ring is smaller in the
 +
female than in the male.
 +
 
 +
The linea alba has been already described (see p. 704).
 +
 
 +
The lumbar triangle (triangle of Petit) is only present when the latissimus dorsi and external oblique do not meet. It is situated immediately
 +
above the centre of the iliac crest, and is bounded in front by the
 +
posterior border of the external oblique, behind by the anterior border
 +
of the latissimus dorsi, and below by the central portion of the iliac crest.
 +
It is covered only by skin and fascia, and its floor is formed by a part
 +
of the internal oblique. In this situation a lumbar hernia may occur,
 +
or a lumbar abscess may find its way to the surface.
 +
 
 +
Obliquus Internus Abdominis — Origin. —(1) The deep or abdominal
 +
surface of the inguinal ligament over its outer half or two-thirds;
 +
 
 +
(2) the middle lip of the iliac crest over its anterior two-thirds; and
 +
 
 +
(3) the posterior layer of the lumbar fascia of the transversus abdominis.
 +
 
 +
Insertion. —(1) The lower borders of the cartilages of the lower
 +
 
 +
three ribs; (2) the lower borders of the cartilages of the seventh, eighth,
 +
and ninth ribs, and the side of the xiphoid process of the sternum;
 +
(3) the linea alba in its whole length; (4) the pubic crest; and (5) the
 +
medial portion of the pectineal line for \ inch.
 +
 
 +
Nerve-supply. —This is similar to that of the external oblique, with
 +
the addition of twigs from the ilio-inguinal nerve and the anterior
 +
branch of the ilio-hypogastric, both of which are derived from the
 +
lumbar plexus, more particularly the first lumbar nerve.
 +
 
 +
Action —This is similar to that of the external oblique. When
 +
the right internal oblique acts simultaneously with the left external
 +
oblique, the trunk is rotated to the right side, and vice versa. To
 +
understand this action, it is to be noted that the fibres of the internal
 +
oblique of one side coincide in direction with those of the external
 +
oblique of the opposite side.
 +
 
 +
Most of the fibres pass upwards and forwards across those of the
 +
external oblique, coinciding in direction with those of the internal
 +
intercostal muscles. The fibres from the inguinal ligament, however,
 +
pass downwards and inwards, and join the corresponding fibres of the
 +
transversus abdominis to form the conjoint tendon. The aponeurosis
 +
is broader above than below. In its upper three-fourths it divides at
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
723
 +
 
 +
 
 +
e outer border of the rectus abdominis into two laminae, one of which
 +
sses in front of the muscle and the other behind it. The anterior
 +
Inina joins the aponeurosis of the external oblique, and the posterior
 +
mina joins the anterior aponeurosis of the transversus. It is this
 +
tter lamina which has an insertion into the seventh, eighth, and ninth
 +
>stal cartilages and xiphoid process. In its lower fourth the aponeurosis
 +
r a in divides at the outer border of the rectus, but the division is not
 +
! apparent; the fibres forming the anterior lamina pass as before in
 +
3 nt of the rectus to join the aponeurosis of the external oblique;
 +
L e fibres forming the posterior
 +
mina, on the other hand, curve
 +
iwnwards, and, passing along
 +
ie outer border of the rectus,
 +
iin the aponeurosis of the transsrsus, the fibres of which are
 +
milarly directed, to form the
 +
Dnjoint tendon, which in certain
 +
ises may be said to form a slot
 +
1 which the outer border of the
 +
ictus fits. The fibres of the
 +
mscle which arise from the inuinal ligament are at their
 +
rigin in front of the spermatic
 +
ord as it lies in the upper third
 +
f the inguinal canal. They then
 +
rch over it, and finally descend
 +
>ehind it as it lies in the lower
 +
wo-thirds of the inguinal canal,
 +
n this latter situation the fibres
 +
Lave terminated in the conjoint
 +
endon.
 +
 
 +
Cremaster — Origin .—The deep
 +
.spect of the inguinal ligament
 +
n its inner part. A few fibres
 +
ire also derived from the lower
 +
)order of the internal oblique.
 +
 
 +
Qie fibres descend in a series
 +
)f loops upon the outer and
 +
interior aspects of the spermatic cord. The lowest loops reach the
 +
:unica vaginalis of the testis, upon the upper part of which they
 +
spread out in an arched manner, some of the fibres terminating on
 +
t. The other loops are successively shorter from below upwards, and
 +
ascend on the inner and posterior aspects of the cord, where they
 +
become tendinous and indefinite, to gain insertion into the pubic tubercle
 +
and anterior lip of the pubic crest. The loops of the muscle are
 +
separated by intervals occupied .by areolar tissue. This combination
 +
of muscular loops and areolar tissue forms the cremasteric fascia. The
 +
cremaster muscle lies in series with the lower border of the internal
 +
 
 +
 
 +
 
 +
Fig. 426A. —Diagram to show how the
 +
Lower Fibres of Internal Oblique
 +
form a Cremaster Muscle (CM)
 +
 
 +
CONTINUOUS WITH CREMASTERIC FASCIA (CF).
 +
 
 +
I.Sp.F., internal spermatic fascia;
 +
 
 +
C, conjoint tendon.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
724
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
oblique, and is peculiar to the male. It is occasionally represented i
 +
the female by a few fibres which descend on the ligamentum teres c
 +
the uterus in the inguinal canal.
 +
 
 +
Nerve-supply .—The genital branch of the genito-femoral nerv
 +
from the lumbar plexus, more particularly from the first and th
 +
ventral division of the second lumbar nerves.
 +
 
 +
Action .—To support and raise the testis towards the superfici;
 +
inguinal ring. The fibres composing the muscle are of the striate
 +
variety, but the action is involuntary, and of a reflex character.
 +
 
 +
 
 +
 
 +
Cremasteric Reflex. —The afferent nerve involved in the cremasteric reflex
 +
either the ilio-inguinal, which is distributed to the side of the scrotum and inn(
 +
side of the thigh, or the femoral branch of the genito-femoral, which is distribute
 +
to the integument over the femoral triangle. The efferent nerve is the geniti
 +
branch of the genito-femoral.
 +
 
 +
Transversus Abdominis — Origin. — : (i) The deep aspect of the it
 +
guinal ligament over its outer third; (2) the inner lip of the iliac ere::
 +
over its anterior two-thirds; (3) the lumbar fascia, which by its postern
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
725
 +
 
 +
 
 +
xr is connected with the spinous processes of the lumbar and sacral
 +
:tebne and the posterior fourth of the outer lip of the iliac crest, by
 +
middle layer with the tips of the lumbar transverse processes, and
 +
its anterior layer with the anterior surfaces of the lumbar transrse processes; and (4) the inner surfaces of the cartilages of the
 +
ver six ribs by six slips which interdigitate with slips of the
 +
iphragm.
 +
 
 +
Insertion. —(1) The linea alba; (2) the pubic crest; and (3) the
 +
Mial portion of the pectineal line for 1 inch.
 +
 
 +
Nerve-supply. —This is similar to that of the internal oblique.
 +
Action. —To diminish the capacity of the abdominal cavity, and
 +
compress the viscera. To a limited extent the two muscles aid
 +
e external and internal oblique muscles in elevating the pelvis, flexing
 +
e thorax, and depressing the ribs.
 +
 
 +
Most of the fibres pass transversely forwards, and terminate in the
 +
iterior aponeurosis. The fibres, however, from the inguinal ligament
 +
iss downwards and inwards, and join the corresponding fibres of the
 +
ternal oblique to form the conjoint tendon. The anterior aponeurosis
 +
narrow above, but broad below. The narrowness above is due to
 +
Le fact that for some distance below the xiphoid process the muscular
 +
ires of the transversus are continued behind the rectus, and only
 +
scome aponeurotic on nearing the linea alba. In its upper threelurths the aponeurosis passes behind the rectus muscle, but in its
 +
wer fourth it passes down along its lateral margin. The transversus
 +
idominis is continuous superiorly with the transversus thoracis muscle,
 +
id its lower border is free where it arches over the spermatic cord or
 +
le ligamentum teres of the uterus.
 +
 
 +
For the posterior aponeurosis of the muscle, see p. 840.
 +
 
 +
Conjoint Tendon. —This is the tendon which gives a common inseron to the fibres of the internal oblique and transversus abdominis
 +
luscles which arise from the inguinal ligament. It is inserted into
 +
[) the pubic crest, and (2) the medial portion of the pectineal line
 +
ir 1 inch. The tendon is formed principally by the transversus
 +
bdominis, which extends for 1 inch along the pectineal line, whilst the
 +
iternal oblique only extends along that line for \ inch.
 +
 
 +
Relations — Superficial .—The structures in front of the conjoint tendon, from
 +
he middle line outwards, are as follows: the lower part of the superior crus of the
 +
uperficial inguinal ring; the triangular fascia; the insertion of the cremaster;
 +
ectineal part of inguinal ligament; the inner part of the inguinal ligament; and
 +
he spermatic cord. Deep .—The fascia transversalis.
 +
 
 +
The conjoint tendon varies greatly in development, and in many cases is
 +
tardly distinguishable. As a rule, it covers the inner two-thirds of the floor
 +
»f the inguinal triangle, where it lies behind the inner two-thirds of the inguinal
 +
anal, and has the spermatic cord, or the ligamentum teres of the uterus, as a
 +
uperficial relation. It also lies directly behind the superficial inguinal ring, and
 +
0 strengthens what would otherwise be a weak part of the abdominal wall.
 +
 
 +
Interfoveolar Ligament. —In normal circumstances the conjoint tendon is
 +
united to the first inch of the medial portion of the pectineal line. Sometimes,
 +
lowever, the anterior aponeurosis of the transversus abdominis is prolonged
 +
outwards beyond the normal limit of the conjoint tendon in the form of a thin
 +
 
 +
 
 +
726
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
semilunar expansion which extends as far as the inner and lower parts of
 +
deep inguinal ring, and is attached interiorly to the deep crural arch. 1
 +
semilunar expansion of the conjoint tendon is known as the interfoveolar ligame
 +
Its concavity is directed outwards, and, when present, it covers the outer th
 +
of the floor of the inguinal triangle, where it lies behind the spermatic cord, i
 +
is closely connected with the subjacent fascia transversalis, to which it imps
 +
strength.
 +
 
 +
An inspection of the external oblique, internal oblique, and tra:
 +
versus abdominis muscles shows that they cross each other at differc
 +
angles, the external oblique passing downwards and forwards, t
 +
internal oblique upwards and forwards (these two muscles thus crossi
 +
like the limbs of the letter X), and the transversus horizontally forwan
 +
They thus form an intricate lattice-work which renders the abdomii
 +
wall very strong, and is a powerful safeguard against hernial pi
 +
trusions.
 +
 
 +
Rectus Abdominis — Origin .—This muscle arises by two hea<
 +
both of which are tendinous. The lateral head, broad and flat, ark
 +
from the pubic crest, and the medial head, narrow and somewhat rour
 +
from the fibrous structures in front of the symphysis pubis, where if
 +
closely connected with its fellow of the opposite side. The two hea
 +
join about i inch above the symphysis pubis.
 +
 
 +
Insertion .—By means of three flat slips, which are at first flesl
 +
and subsequently tendinous, into the anterior surfaces of the fift
 +
sixth, and seventh costal cartilages. The most medial slip is som
 +
times partially inserted into the side of the xiphoid process of t
 +
sternum.
 +
 
 +
Nerve-supply .—The lower five intercostal nerves and the subcosf
 +
nerve.
 +
 
 +
Action .—The action is similar to that of the two oblique ai
 +
transversus muscles, with the exception that it does not produ
 +
lateral rotation of the thorax.
 +
 
 +
The muscle is long, flat, and strap-like, its fibres being direct<
 +
vertically upwards by the side of the linea alba. It is narrow belc
 +
and broad above, its greatest breadth being about 3 inches. Belc
 +
the umbilicus the two muscles are very near each other, the interv
 +
between them being not more than about J inch. Above the umbilicr
 +
however, the muscles are separated by an interval of about J inc'
 +
Each muscle is marked by tendinous intersections which cross it in
 +
somewhat irregular manner at certain intervals. They are usual,
 +
three in number, and are situated as follows: one at the level of tl
 +
umbilicus, a second opposite the margin of the thorax, and a thii
 +
about midway between these two. Sometimes there is a fourth inte
 +
section, which crosses the muscle a little below the umbilicus, but th
 +
one is faint, and does not usually extend the whole width. These inte
 +
sections, which do not usually penetrate to the posterior surface, ma
 +
out the upper part of the muscle into quadrangular areas, and ai
 +
firmly bound to the anterior wall of its sheath. Above the level of tl
 +
umbilicus, therefore, the interior of the sheath, anterior to the muscl
 +
is divided into distinct compartments.
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
727
 +
 
 +
 
 +
The tendinous intersections are the intersegmental parts of the lateral sheets
 +
)f mesoderm. The muscles of the abdominal wall, including the rectus, are
 +
'ormed from ventral downgrowths derived from the somites, and therefore
 +
segmental in nature. The downgrowths pass ventrally in the lateral mesodermal
 +
sheet, and the parts of the lateral sheet remaining between the separate downgrowths are hence intersegmental; they are best marked between the ventral
 +
extremities of the downgrowths, which are not so broad here. The lateral sheet
 +
mly forms the simple connective tissues in the trunk, never muscular tissue,
 +
md in most cases the intersegmental lines show as the tendinous lines in the
 +
rectus; in some animals, however, such as the crocodile, the connective tissue
 +
becomes fibro-cartilaginous in nature, making what are sometimes termed
 +
abdominal ribs ' in these animals. In man they serve the purpose of strengthening the muscle.
 +
 
 +
Pyramidalis — Origin .—The front of the pubic crest.
 +
 
 +
Insertion .—The linea alba for 2 inches or more above the symphysis
 +
pubis.
 +
 
 +
Nerve-supply .—The subcostal nerve.
 +
 
 +
Action .—To render tense the linea alba.
 +
 
 +
The muscle is sometimes present only on one side; sometimes it is
 +
absent on both sides; and sometimes it is double on one or both sides.
 +
In man it is a small muscle, and vestigial like the plantaris; but it
 +
attains a large size in marsupials and monotremes, and is attached
 +
to the epipubic bone of these mammals. It is frequently separated
 +
in man from the rectus by a fascial expansion from the conjoint
 +
tendon.
 +
 
 +
Sheath of Rectus Abdominis. —Above the level of the thoracic
 +
margin the sheath of the rectus is deficient posteriorly, and is formed
 +
anteriorly by the aponeurosis of the external oblique; from the thoracic
 +
margin to a level about midway between the umbilicus and the
 +
symphysis pubis the anterior wall is formed by the anterior lamina of
 +
the internal oblique aponeurosis and the external oblique aponeurosis,
 +
the two being closely connected, and the posterior wall is formed by
 +
the posterior lamina of the internal oblique aponeurosis and the anterior
 +
aponeurosis of the transversus abdominis, these two being likewise
 +
closely connected. Below a line midway between the umbilicus and
 +
symphysis the anterior wall is formed by the aponeurosis of the external
 +
oblique reinforced by fibres derived from the aponeurosis of the internal
 +
oblique, and the posterior wall is only represented by the fascia transversalis, since part of the aponeurosis of the internal oblique here blends
 +
with the aponeurosis of the transversus to form the conjoint tendon,
 +
which, instead of passing inwards, curves downwards, skirting the
 +
lateral border of the rectus.
 +
 
 +
The line along which this transition occurs is curved with the concavity downwards, and is known as the arcuate line (fold of Douglas).
 +
This so-called fold is extremely variable, sometimes scarcely apparent,
 +
at other times multiple. When well developed it is traceable to the
 +
linea alba at its upper and inner extremity, and to the pubic crest,
 +
where it blends with the inner edge of the conjoint tendon at its lower
 +
and outer extremity. It thus bounds supero-laterally a large oval
 +
area, within which the inferior epigastric vessels pierce the fascia trans
 +
 
 +
 
 +
728
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
versalis, and so enter the sheath of the rectus. These vessels, as th
 +
course upwards, pass anterior to the fold.
 +
 
 +
The contents of the sheath are as follows: the rectus abdomin
 +
pyramidalis, inferior epigastric vessels, superior epigastric vessels, ai
 +
terminal parts of the lower five intercostal and subcostal nerves.
 +
 
 +
Relation of Structures at the Pubic Crest. —The relation of structures fn
 +
 
 +
before backwards is as follows:
 +
 
 +
1. The reflected part of inguinal ligament.
 +
 
 +
2. The conjoint tendon splitting medianly to enclose the lateral margins
 +
the pyramidalis and rectus.
 +
 
 +
3. The pyramidalis.
 +
 
 +
4. The outer head of the rectus abdominis.
 +
 
 +
5. The fascia transversalis.
 +
 
 +
A few fibres of the cremaster are inserted into the pubic crest close to the pul
 +
tubercle.
 +
 
 +
Relation of Structures at the Medial Portion of the Pectineal Line. —The relati<
 +
 
 +
of structures from before backwards is as follows:
 +
 
 +
1. The pubic lamina of the fascia lata, incorporated with which is the pectinc
 +
(ligament of Cooper) ligament.
 +
 
 +
2. The pectineus.
 +
 
 +
3. Pectineal part of inguinal ligament.
 +
 
 +
4. The conjoint tendon.
 +
 
 +
5. The fascia transversalis and the deep femoral arch.
 +
 
 +
Deep Nerves of the Abdominal Wall. —The lower five intercost
 +
nerves, after leaving the intercostal spaces, lie between the intern
 +
oblique and transversus abdominis, and pass downwards and forwar<
 +
to the outer border of the rectus. Here they pierce in succession tl
 +
posterior wall of the sheath, the rectus, and the anterior wall of tl
 +
sheath, after which they terminate as the anterior cutaneous nerve
 +
In their course they supply the two oblique, the transversus, and tl
 +
rectus muscles. Each nerve gives off a lateral cutaneous branch :
 +
the mid-axillary line. These lateral cutaneous branches, having pierce
 +
the internal oblique, appear between the slips of the external oblique ar
 +
divide into anterior and posterior branches.
 +
 
 +
The subcostal nerve is the anterior primary division of the twelft
 +
thoracic nerve. It is in series with the eleventh intercostal, but
 +
not ranked as an intercostal nerve, inasmuch as it lies along the low*
 +
border of the twelfth rib. It is commonly spoken of as the last thorac
 +
nerve. Its abdominal relations, course, and distribution are simik
 +
to the preceding nerves, with an additional distribution to the pyram
 +
dalis abdominis. Its lateral cutaneous branch, which is undivide*
 +
having pierced the internal and external oblique muscles, descenc
 +
over the anterior part of the iliac crest 1 inch behind the anteric
 +
superior iliac spme, and is distributed to the skin of the anterior pai
 +
of the gluteal region as low as the greater trochanter of the femur; th
 +
nerve is very variable in size, and is not infrequently absent.
 +
 
 +
The ilio-hypogastric nerve, having pierced the posterior part of tb
 +
transversus abdominis a little above the iliac crest, furnishes its latere
 +
cutaneous' branch, which perforates the internal and external obliqu*
 +
and, having crossed the iliac crest at the junction of its middle an
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7 2 9
 +
 
 +
 
 +
aterior thirds, is distributed to the skin of the adjacent part of the
 +
luteal region. The nerve then continues its course forwards between
 +
re internal oblique and transversus, supplying branches to these
 +
mscles and communicating with the ilio-inguinal nerve. About
 +
inch in front of the anterior superior iliac spine it pierces the internal
 +
blique, and runs forwards between that muscle and the external
 +
blique aponeurosis. Finally, it pierces that aponeurosis about i inch
 +
bove the superficial inguinal ring, and is distributed to the skin of the
 +
iprapubic region, where
 +
 
 +
is in series with the
 +
nterior cutaneous nerves.
 +
 
 +
The ilio-inguinal nerve,
 +
s it passes forwards, lies
 +
ist above, or it may be
 +
ledial to the inner lip of,
 +
le iliac crest, beneath
 +
tie transversus muscle.
 +
 
 +
[ear the anterior part of
 +
tie iliac crest it pierces
 +
tie transversus, and here
 +
ommunicates with the
 +
nterior cutaneous branch
 +
f the ilio - hypogastric,
 +
t subsequently perforates
 +
he internal oblique, after
 +
diich it descends through
 +
he lower two-thirds of
 +
he inguinal canal, and
 +
merges through the
 +
uperficial inguinal ring,
 +
 
 +
/here it lies lateral to the
 +
permatic cord. Finally,
 +
t is distributed to the
 +
kin of the inner side of
 +
he thigh in its upper
 +
hird, and to the skin of
 +
he scrotum or labium
 +
fiajus, according to the
 +
ex. The nerve in its course supplies branches to the internal oblique
 +
nd transversus muscles. The fibres of the ilio-hypogastric and ilionguinal nerve often run for a variable distance within the same sheath.
 +
 
 +
Deep Arteries of the Abdominal Wall.— The inferior epigastric
 +
artery arises from the inner side of the external iliac, about \ inch
 +
hove the inguinal ligament. At first for a very short distance it
 +
)asses inwards between the inguinal ligament and the lower border
 +
>f the deep inguinal ring, lying in the extraperitoneal fatty tissue. It
 +
hen changes its course, and passes upwards and inwards, lying close to
 +
he inner side of the deep inguinal ring, only the external vena comes
 +
 
 +
 
 +
 
 +
Fig. 428. —Deep Nerves of Abdominal Wall
 +
 
 +
LYING BETWEEN TRANSVERSUS AND INTERNAL
 +
 
 +
Oblique (IO).
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
730
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
intervening. On arriving at the outer border of the rectus abdomir
 +
at a point about midway between the upper border of the symphy
 +
pubis and the umbilicus, it pierces the fascia transversalis, and ascen
 +
within the sheath over the arcuate line of the sheath of the recti
 +
It then changes its course, and ascends vertically between the mus<
 +
and the posterior wall of the sheath as high as the umbilicus. Here
 +
enters the muscle, and about 2 inches above the umbilicus ends in
 +
terminal branches, which anastomose with branches of the super:
 +
epigastric artery. The inferior epigastric lies at first in the subpe
 +
toneal areolar tissue, having the parietal peritoneum on its deep surfa
 +
 
 +
 
 +
P 1
 +
 
 +
 
 +
 
 +
Fig. 429.— Scheme of Vascular Anastomosis on the Posterior Wall
 +
 
 +
Sheath of Rectus.
 +
 
 +
and the fascia transversalis superficial to it. Shortly after passing t
 +
deep inguinal ring the vessel pierces the fascia transversalis, and in i
 +
course to the outer border of the rectus forms the outer boundary
 +
the inguinal triangle. As the vessel turns from the lower border
 +
the inner sides of the deep inguinal ring it has the spermatic cord
 +
front of it, and the vas deferens here hooks round its outer side. Ti
 +
course of the vessel in its first or oblique part is indicated by a lii
 +
drawn from the inner border of the deep inguinal ring to the out
 +
border of the rectus abdominis at a point about midway between t]
 +
umbilicus and the upper border of the symphysis pubis. The cour
 +
of the second or vertical part of the vessel is represented by a vertic
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
73 i
 +
 
 +
 
 +
ne corresponding with the centre of the rectus, and distant from the
 +
nea alba about i| inches.
 +
 
 +
Branches. —These are as follows: cremasteric, pubic, muscular,
 +
iitaneous, peritoneal, and terminal or anastomotic.
 +
 
 +
The cremasteric artery enters the spermatic cord and supplies the
 +
remaster muscle and the other coverings of the cord. It anastomoses
 +
ith the testicular artery, the superficial and deep external inferior
 +
rteries, and the superficial perineal artery. The cremasteric artery
 +
; replaced in the female by the artery of the ligamentum teres of the
 +
ter us.
 +
 
 +
The pubic artery passes inwards behind the inner half of the inuinal ligament to the back of the body of the os pubis, where it anastoloses with the pubic branch of the obturator artery and its fellow of
 +
tie opposite side.
 +
 
 +
The muscular branches arise chiefly from the outer side of the
 +
iferior epigastric, and supply the two oblique, transversus, and rectus
 +
mscles. They anastomose with the lower two posterior intercostal
 +
rteries, the subcostal artery, the abdominal branches of the lumbar
 +
rteries, and a large ascending branch of the deep circumflex iliac
 +
rtery.
 +
 
 +
The cutaneous branches perforate the rectus and the anterior wall
 +
f its sheath, to be distributed to the skin, in which they anastomose
 +
nth branches of the superficial epigastric.
 +
 
 +
The peritoneal branches pierce the posterior wall of the sheath of
 +
he rectus, to be distributed to the adjacent parietal peritoneum.
 +
 
 +
The terminal or anastomotic branches enter the rectus above the
 +
svel of the umbilicus, and anastomose with the superior epigastric of the
 +
nternal mammary.
 +
 
 +
For the abnormal obturator artery, see p. 566.
 +
 
 +
There are two venae comites with the inferior epigastric artery, one
 +
>n either side. These ultimately join to form one vessel, which
 +
erminates in the external iliac vein.
 +
 
 +
The superior epigastric artery is one of the terminal branches of the
 +
nternal mammary from the first part of the subclavian. It descends
 +
)ehind the seventh costal cartilage, passes between the sternal and
 +
:ostal portions of the diaphragm, and enters the sheath of the rectus,
 +
vhere it lies at first between the muscle and the posterior wall of its
 +
heath. It then enters the muscle and anastomoses with the inferior
 +
pigastric. Its branches are as follows: sternal , which crosses in front
 +
>f the xiphoid process and anastomoses with its fellow of the opposite
 +
'ide; phrenic , to the diaphragm; muscular, to the muscles of the ablominal wall; anterior cutaneous, to the skin; hepatic (present only on
 +
he right side), which passes to the liver in the falciform ligament and
 +
mastomoses with the hepatic artery; and peritoneal, which pierce the
 +
posterior wall of the sheath of the rectus, to be distributed to the
 +
adjacent parietal peritoneum. The vessel is accompanied by two
 +
^enae comites, which terminate in those of the internal mammary
 +
utery.
 +
 
 +
 
 +
732
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
The deep circumflex iliac artery arises from the outer side of 1
 +
external iliac, nearly opposite the origin of the inferior epigastric,
 +
passes outwards and upwards behind the outer half of the ingui]
 +
ligament, where it is contained in a canal formed at the junction
 +
the fascia transversalis and fascia iliaca. Having arrived at 1
 +
anterior superior iliac spine, it pierces the fascia transversalis, a
 +
courses outwards and backwards along the iliac crest on its ini
 +
aspect. At its termination it anastomoses with the lumbar brar
 +
of the ilio-lumbar from the internal iliac. Over about the anter
 +
half of the iliac crest the artery lies beneath the transversus muse
 +
but about the centre of the crest it pierces that muscle, and sub
 +
quently lies between it and the internal oblique.
 +
 
 +
Branches. —In the first part of its course the vessel gives branches
 +
the ilio-psoas, sartorius, and tensor fasciae latae, in which latter mus
 +
it anastomoses with the ascending branch of the external circumfl
 +
from the arteria profunda femoris. As it courses along the iliac cr<
 +
it furnishes branches to the muscles of the abdominal wall, some
 +
which reach the gluteal region, where they anastomose with the super:
 +
gluteal of the internal iliac and the superficial circumflex iliac of t
 +
femoral. It also gives branches to the iliacus muscle, which anasi
 +
mose with the iliac branch of the ilio-lumbar from the internal ill;
 +
One of the muscular branches of the artery is very constant and
 +
large size. It springs from the vessel near the anterior superior ili
 +
spine, and, having pierced the fascia transversalis and transvers
 +
muscle, it ascends vertically between that muscle and the interr
 +
oblique, where it anastomoses with the abdominal branches of t
 +
lumbar arteries. This branch is usually spoken of as the ascendi
 +
branch.
 +
 
 +
The deep circumflex iliac artery is accompanied by two vei
 +
comites. These ultimately join to form one vessel, which crosses t
 +
external iliac artery from without inwards about \ inch above t
 +
inguinal ligament, and terminates in the external iliac vein.
 +
 
 +
The lower two posterior intercostal arteries ultimately leave t
 +
tenth and eleventh intercostal spaces, and pass towards the rect
 +
muscle, lying in their course between the internal oblique and trar
 +
versus. They anastomose with the superior epigastric, inferi
 +
epigastric, and subcostal arteries.
 +
 
 +
The subcostal artery lies below the last rib, and is in series wi
 +
the posterior intercostal arteries above and the lumbar arteries bekr
 +
In the abdominal wall it anastomoses with the last intercostal, tl
 +
abdominal branch of the first lumbar, and the superior epigastr
 +
arteries.
 +
 
 +
The abdominal branches of the lumbar arteries pass forwan
 +
towards the rectus abdominis. They anastomose with the inferi<
 +
epigastric, subcostal, and ascending branch of the deep circumfk
 +
iliac.
 +
 
 +
The veins corresponding to the lower two posterior intercost:
 +
arteries terminate in the corresponding intercostal veins. The subcost;
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
733
 +
 
 +
 
 +
ein of the right side terminates in the azygos vein, and that of the
 +
:ft side in the inferior vena hemiazygos. The veins accompanying
 +
re abdominal branches of the lumbar arteries terminate in the lumbar
 +
eins, which are tributaries of the inferior vena cava.
 +
 
 +
Deep Lymphatics. —The deep lymphatics of the lower part of the
 +
nterior abdominal wall accompany the inferior epigastric and deep
 +
ircumflex iliac vessels, and terminate in the external iliac glands;
 +
lose of the upper part accompany the superior epigastric artery, and
 +
irminate in the sternal glands.
 +
 
 +
The deep lymphatics of the lower part of the lateral abdominal
 +
r all accompany the abdominal branches of the lumbar arteries, and
 +
 
 +
 
 +
 
 +
Intercrural Saphenous Superficial X Interfoveolar
 +
 
 +
Fibres Opening Inguinal Ring Ligament
 +
 
 +
 
 +
ig. 430. —Superficial and Deep Dissection of the Lower Part of the
 +
Anterior Abdominal Wall (after Cooper).
 +
 
 +
E. O.A. External Oblique Aponeurosis I.A.R. Deep Inguinal Ring
 +
 
 +
O.I.A. Obliquus Internus Abdominis S.C. Spermatic Cord
 +
 
 +
T.A. Transversus Abdominis D.E.V. Inferior Epigastric Vessels
 +
 
 +
F. T. Fascia Trans versalis X. Reflected Part of Inguinal Ligament
 +
 
 +
 
 +
srminate in the lateral group of lumbar glands; those of the upper
 +
art accompany the adjacent anterior intercostal and musculo-phrenic
 +
rteries, and terminate in the sternal glands.
 +
 
 +
For the superficial lymphatics of the antero-lateral abdominal
 +
fall, see p. 712.
 +
 
 +
Fascia Transversalis. —The fascia transversalis is situated undereath the transversus abdominis muscle. It is of greatest strength
 +
ver the lower part of the abdominal wall, particularly between the
 +
)wer free border of the transversus and the inguinal ligament. When
 +
faced upwards to the costal margin it becomes very thin, and is there
 +
ontinuous with the fascia which covers the abdominal surface of the
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
734
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
diaphragm. Along the linea alba it is continuous with the fascia
 +
the opposite side. In the lumbar region it is continuous with t]
 +
anterior wall of the sheath of the quadratus lumborum. In the regi<
 +
of the iliac crest it is attached to the anterior two-thirds of the ere
 +
immediately medial to its inner lip, where it meets and becomes co
 +
tinuous with the fascia iliaca, both of these fasciae being here interpos<
 +
between the transversus and iliacus muscles. The most importa:
 +
disposition of the fascia is along the line of the groin, where its attac
 +
ments are as follows: along the outer half of the inguinal ligament it
 +
firmly attached to that ligament on its deep aspect, and over th;
 +
extent it meets and is continuous with the fascia iliaca, the two fasci
 +
 
 +
 
 +
Gbliquus Internus Abdominis
 +
 
 +
 
 +
Transversus Abdominis-/ r
 +
 
 +
Gbliquus Externus,.
 +
Abdominis
 +
 
 +
 
 +
Pectineus_—- 0
 +
 
 +
 
 +
Sartorius _
 +
Adductor Longus
 +
 
 +
 
 +
Umbilicus
 +
 
 +
I
 +
 
 +
 
 +
 
 +
_Rectus Abdominis
 +
 
 +
 
 +
— Spermatic Cord
 +
 
 +
 
 +
. Suspensory Ligament of Penis
 +
 
 +
 
 +
Ilio-inguinal Nerve
 +
 
 +
 
 +
Fig. 431.— Dissection of the Inguinal Region.
 +
 
 +
 
 +
here forming a canal, which contains the deep circumflex iliac vessels
 +
In the situation of the external iliac vessels, and as far inwards as th
 +
base of the pectineal part of inguinal ligament, it is only loosely attache<
 +
to the inguinal ligament, and is here prolonged downwards beneat]
 +
the ligament to the thigh, where it lies in front of the femoral vessels
 +
and forms the anterior wall of the femoral sheath. As the fascia i
 +
prolonged beneath the inguinal ligament it is strengthened by super
 +
added fibres, which are known as the deep femoral arch. In the regior
 +
of the pectineal part of inguinal ligament the fascia is attached in succession to the medial portion of the pectineal line behind the conjoinl
 +
tendon, and to the pubic crest. Behind the symphysis pubis the fascia
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
735
 +
 
 +
lescends into the pelvis, and becomes continuous with the pubo-prosatic, or anterior true, ligaments of the bladder. The strongest part
 +
f the fascia transversalis, as before stated, is between the lower free
 +
•order of the transversus muscle and the inguinal ligament, this part
 +
f fhe abdominal wall being uncovered by muscular structures. It is
 +
i this situation that the fascia is pierced by the spermatic cord in
 +
he male and the ligamentum teres of the uterus in the female.
 +
 
 +
Deep Inguinal Ring. This ring is situated in the fascia transversalis
 +
t a point midway between the symphysis pubis and the anterior superior
 +
iac spine, and ^ inch above the inguinal ligament. It serves for the
 +
assage of the spermatic cord in the male and the ligamentum teres of
 +
tie uterus in the female. As viewed from the front, no opening is
 +
isible in the undissected state, because the fascia transversalis is pronged like the finger of a glove round the spermatic cord as the internal
 +
permatic fascia. When fully dissected the ring is oval, with the long
 +
xis lying vertically, in which direction it measures § inch, the transerse measurement being f inch. The inferior epigastric artery lies at
 +
 
 +
 
 +
 
 +
M. Oblig. Interims
 +
Transversalis Fascia
 +
Conjoint Tendon
 +
 
 +
Aponeurosis of Oblig. Ext.
 +
 
 +
Ext. Spermatic Fascia
 +
Cremasteric Fascia
 +
Int. Spermatic Fascia
 +
Spermatic Cord.
 +
 
 +
ig. 432. —Scheme to show the Composition of the Front and Back Walls
 +
of Inguinal Canal, and Derivations of Coverings of the Cord.
 +
 
 +
 
 +
rst below, and then on the inner side of, the ring, the vessel being
 +
sre beneath the fascia transversalis. The interfoveolar ligament may
 +
2 upon the inner side of, and below, the ring. In front of the ring
 +
~ e the lower fibres of the internal oblique, and above is the lower free
 +
irder of the transversus. The fascia at the outer and lower parts
 +
the ring is stronger than elsewhere.
 +
 
 +
Inguinal Canal. —The inguinal canal is the oblique passage in the
 +
wer part of the anterior abdominal wall, which transmits the spermatic
 +
)rd or ligamentum teres of the uterus, according to the sex, and also
 +
Ie inguinal nerve in its lower two-thirds. It is situated immediately
 +
)ove the inner half of the inguinal ligament, its direction being downards, forwards, and inwards, and it is ij inches in length. The inlet
 +
> the canal is the deep inguinal ring, the outlet being the superficial
 +
guinal ring. Its component parts are a floor, a roof, an anterior wall,
 +
id a posterior wall. The floor in its upper two-thirds is formed by
 +
 
 +
meeting between the fascia transversalis and the inguinal ligament,
 +
ms portion of it presents a groove, which lodges the spermatic cord.
 +
 
 +
1 the lower third the floor is formed by the abdominal surface of the
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
736
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
pectineal part of inguinal ligament along its line of junction with 1
 +
latter. The roof is formed by the approximation of the anterior a
 +
posterior walls, separated only by the lower border of the transvers
 +
The anterior wall is formed by the following structures from bef<
 +
backwards: (i) the skin; (2) the superficial fatty and deeper me
 +
branous layers of the fascia of the anterior abdominal wall; (3) exter]
 +
oblique aponeurosis (all these four structures extending over the wh
 +
length of the anterior wall); and (4) the lower fibres of the interi
 +
oblique over the outer third. The posterior wall is formed by t
 +
following structures, in order from behind forwards: (1) the parie
 +
peritoneum; (2) subperitoneal fat; (3) fascia transversalis; (4) conjo:
 +
tendon over the inner two-thirds, and it may be the interfoveolar I4
 +
ment over the outer third; and (5) the outer portion of the reflect
 +
part of inguinal ligament (provided that ligament is well developer
 +
which forms anteriorly the extreme inner part of this wall.
 +
 
 +
In early life the inguinal canal is very short. Indeed, at one peri
 +
of life it is non-existent, inasmuch as the deep inguinal ring in ve
 +
early life lies directly behind the superficial ring. As the pelvis, ho
 +
ever, increases in breadth, the deep ring is gradually shifted outwan
 +
and so the inguinal canal becomes formed.
 +
 
 +
The inguinal canal in the female differs from that in the male
 +
being of smaller size, and in containing the ligamentum teres of t
 +
uterus.
 +
 
 +
Inguinal Triangle (Hesselbach’s Triangle). —This triangle is situat
 +
at the lower part of the anterior abdominal wall above the inner h;
 +
of the inguinal ligament.
 +
 
 +
Boundaries — Medial .—The outer border of the rectus abdomii
 +
over about its lower 2 inches. Lateral .—The inferior epigastric vesse
 +
Inferior (base).—The inner half of the inguinal ligament. The ap
 +
corresponds with the point where the inferior epigastric vessels pa
 +
beneath the outer border of the rectus. The floor is covered over i
 +
whole extent by the fascia transversalis, superficial to which, ov
 +
the inner two-thirds, is the conjoint tendon, and over the outer thi
 +
sometimes the interfoveolar ligament. The floor is, therefore, co
 +
veniently divided into an inner two-thirds, where the conjoint tend<
 +
lies, and an outer third, where the interfoveolar ligament may 1
 +
situated. 1 he triangle is covered superficially by the skin, both laye
 +
of the fascia of the anterior abdominal wall, and the external obliqi
 +
aponeurosis. The triangle is further crossed obliquely by a fibro
 +
cord, the obliterated hypogastric artery, which divides the triangle in
 +
median and lateral portions.
 +
 
 +
Spermatic Cord. —The spermatic cord extends from the deep i
 +
guinal ring to the upper part of the posterior border of the testis. F
 +
the first 1^ inches of its course it lies in the inguinal canal, and is direch
 +
downwards, forwards, and inwards. After passing through the supe
 +
ficial inguinal ring it enters the scrotum, in which it descends almo
 +
vertically, dhe relations of the cord in the inguinal canal will 1
 +
understood on referring to the description of that canal. In the low
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
737
 +
 
 +
 
 +
thirds of the canal it is accompanied by the ilio-inguinal nerve,
 +
:h lies to its outer side.
 +
 
 +
'he spermatic cord is composed of the following structures: the vas
 +
rens; three arteries—namely, the testicular artery, the artery of
 +
vas deferens, and the cremasteric artery; the pampiniform plexus
 +
eins; the lymphatics of the testis and epididymis; the testicular
 +
us of sympathetic nerves; and the genital branch of the genito)ral nerve. These structures are connected by areolar tissue, and
 +
:ord receives certain coverings to be presently described.
 +
 
 +
'he vas deferens is the excretory duct of the testis. It commences
 +
le tail or globus minor of the epididymis, and terminates at the
 +
 
 +
 
 +
 
 +
r iG. 433 - —Transverse Section of the Vas Deferens, showing its
 +
 
 +
Minute Structure.
 +
 
 +
! of the prostate gland by joining the duct of seminal vesicle to form
 +
ejaculatory duct. This latter duct, having passed between the
 +
die and lateral lobes of the prostate gland for about i inch, opens
 +
a the lateral margin of the orifice of the prostatic utricle on the
 +
■ of the prostatic portion of the urethra. The vas deferens at its
 +
mencement is slightly tortuous, but it soon becomes straight. It
 +
at first on the inner side of the epididymis, and along the posterior
 +
ler of the testis. After entering the cord it is placed behind all the
 +
‘r elements, where it can be readily felt and recognized from a resemice to whipcord. It maintains this position until it arrives at the
 +
) inguinal ring, where it lies on the inner side of the other elements
 +
he cord. After passing through the deep inguinal ring it hooks
 +
 
 +
47
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
738
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
round the outer side of the inferior epigastric artery, and, having cros
 +
the external iliac vessels from without inwards, it dips down on
 +
inner side of the external iliac vein, and so enters the pelvis under co
 +
of the peritoneum, where it will be afterwards described. The
 +
deferens in its natural state measures about i foot in length, but w]
 +
straightened attains a length of about if feet.
 +
 
 +
Structure of the Vas Deferens. —The vas deferens has a very thick wall, ;
 +
feels like a piece of whip-cord. Its outer coat consists of fibrous tissue. Wit
 +
this there is a thick muscular coat composed of plain muscular tissue, wl
 +
is arranged in three layers—an outer longitudinal, a middle circular (both
 +
which are thick), and an inner thin longitudinal layer. Within the musci
 +
coat is the mucosa, which is covered by non-ciliated columnar epithelium.
 +
 
 +
Development. —The Wolffian or mesonephric duct is converted into the
 +
deferens in the male, becoming connected with the testis through some of
 +
tubules of the mesonephros. It degenerates in women.
 +
 
 +
The artery of the vas deferens is usually a branch of the super
 +
vesical of the internal iliac, though it may arise from the infer
 +
vesical; it divides into a descending and an ascending branch. 1
 +
descending branch passes downwards to supply the lower part of 1
 +
vas deferens and the seminal vesicle. The ascending branch acco
 +
panies the vas deferens through the inguinal canal to the testis, supp
 +
ing the vas deferens, and giving a few twigs to the tail of the epididyn
 +
in which latter situation it anastomoses with the epididymal brar
 +
of the testicular artery. The artery to the vas is sometimes of lai
 +
size, and may take the place of the testicular artery when that ves
 +
is absent.
 +
 
 +
The vein from the vas opens into the vesical plexus of veins, a
 +
thence into the internal iliac vein.
 +
 
 +
1 he testicular artery arises from the abdominal aorta about i in
 +
below the renal artery. On approaching the upper part of the tes
 +
it divides into glandular and epididymal branches, the former supplyi
 +
the testis and the latter the epididymis. As the artery descends in t
 +
spermatic cord it supplies branches to its coverings which anastomc
 +
with the cremasteric artery; its epididymal branches anastomose wi
 +
the artery of the vas.
 +
 
 +
For the cremasteric artery, see p. 731.
 +
 
 +
The testicular veins issue from the testis along its posterior bordc
 +
In the cord they form a copious plexus, called the pampiniform plexi
 +
At the deep inguinal ring two veins emerge from this plexus, whi<
 +
range themselves on either side of the testicular artery. These, as th(
 +
ascend, soon join to form one vessel, that of the right side opening in
 +
the inferior vena cava, and that of the left side into the left renal vei
 +
The veins of the pampiniform plexus have valves, but they are n<
 +
competent. There is, however, a competent valve as a rule at tl
 +
termination of each testicular vein.
 +
 
 +
The lymphatics of the testis and spermatic cord, the testicuk
 +
plexus of sympathetic nerves, and the genital branch of the genih
 +
femoral nerve will be afterwards described.
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
739
 +
 
 +
 
 +
Coverings of the Spermatic Cord. —The coverings, enumerated from
 +
Tin outwards, are as follows:
 +
 
 +
1. The subperitoneal areolar tissue, which is continuous with that
 +
the abdominal wall through the deep inguinal ring.
 +
 
 +
2. The fascia transversalis, prolonged from the margins of the
 +
sp inguinal ring, and known as the internal spermatic fascia. This
 +
/ering near the ring is funnel-shaped, and is hence called the inidibuliform fascia, but lower down it becomes incorporated with
 +
j subperitoneal areolar tissue and forms the fascia propria of Cooper.
 +
 
 +
3. The cremasteric fascia.
 +
 
 +
 
 +
Testicular Artery
 +
 
 +
 
 +
Pampiniform Plexus of Vein.
 +
 
 +
Epididymal Branch of
 +
Testicular Artery
 +
 
 +
Glandular Branch of
 +
Testicular Artery
 +
 
 +
 
 +
Appendices Testis
 +
 
 +
 
 +
 
 +
Artery of the Vas Deferens
 +
Vas Deferens
 +
 
 +
 
 +
Pampiniform Plexus of Veins
 +
 
 +
 
 +
— Sinus of Epididymis
 +
 
 +
 
 +
Fig. 434. —Dissection of the Spermatic Cord, showing the
 +
Bloodvessels and Duct of the Testis (after Sappey).
 +
 
 +
 
 +
4. The external spermatic fascia.
 +
 
 +
5- The dartos muscle.
 +
 
 +
6. The skin.
 +
 
 +
Within the innermost of these coverings there are a few scattered
 +
uscular fibres, which constitute the internal cremaster of Henle, and
 +
fich are regarded as representing the gubernaculum testis of the
 +
;tus.
 +
 
 +
The fibres of the cremaster proper are of the striated variety, but
 +
ose of the internal cremaster are of the plain variety.
 +
 
 +
Descent of Testis and Formation of Inguinal Canal.— The testis originally
 +
s m the lumbar region of the abdomen, on the mesial side of the Wolffian body
 +
mesonephros. The conditions in the sixth week are shown in Fig. 63.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
740
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
The elongated gonad is attached to the inner side of the mesonephros by
 +
mesorchium (or mesovarium in the female). The mesonephros is attache*
 +
the dorsal wall by the mesonephric mesentery (or mesonephric ligament). M
 +
the mesonephros atrophies, the gonad has the appearance of having more di
 +
dorsal attachment, made by the combination of the original mesorchial
 +
mesonephric attachments, and this is known as the uro-genital mesentery.
 +
 
 +
Gubernaculum Testis. —Near the lower end of the mesonephros a perito
 +
fold is found at a fairly early stage, connecting the uro-genital mesentery 1
 +
the inguinal region at a point corresponding with the site of the future deep 1
 +
The fold is the plica gubernatrix br plica inguinalis. It is seen in Fig. 63, an
 +
a later stage and much thickened in Fig. 69.
 +
 
 +
In the female this fold, as it descends, becomes connected with the cc
 +
sponding para-mesonephric (Mullerian) duct at the level where this duct f
 +
with its fellow to form the rudiment of the uterus and vagina.
 +
 
 +
Within the plica gubernatrix fold a fibro-muscular cord is developed, 1
 +
sisting of connective tissue and plain muscular tissue. This cord is called
 +
gubernaculum testis. Inferiorly it is attached at first to the posterior sur
 +
of the anterior abdominal wall in the inguinal region at a point correspondin
 +
 
 +
 
 +
 
 +
Fig. 435. —Diagram showing the Descent of the Testis.
 +
A, first stage; B, second stage; C, final stage.
 +
 
 +
1 . Testis (in Abdomen) 4. Subperitoneal Areolar Tissue
 +
 
 +
2. Primitive Peritoneum (Tunica Adnata) 5. Fascia Transversalis
 +
 
 +
3 ; Parietal Peritoneum 6. Deep Inguinal Ring
 +
 
 +
3. Processus Vaginalis 7. Integument
 +
 
 +
 
 +
the situation of the future deep inguinal ring, whence it, or the greater par
 +
it, ultimately extends to the bottom of the corresponding scrotal cham
 +
Superiorly its attachment is twofold: (i) it is principally attached to the lo
 +
part of the epididymis at the junction of the tail and vas deferens. (2) A por
 +
of it ascends within the inferior testicular fold to be attached to the cai
 +
end of the testis. According to some authors, the lower part of the gubernacu'
 +
testis is reinforced by striated muscular fibres derived from the internal obli
 +
and transversus abdominis muscles. These fibres, which form the so-ca
 +
inguinal cone, are superadded to the fibro-muscular cord just referred to, wl
 +
constitutes the core of the gubernaculum. Superiorly these superadded fil
 +
from the inguinal cone are described as being attached to the testis and epididyi
 +
Inferiorly, three attachments are ascribed to them as follows: (1) the outer bw
 +
is attached to the deep aspect of the inguinal ligament near its centre; (2)
 +
middle or principal bundle accompanies the gubernaculum testis to the botl
 +
of the scrotal chamber; and (3) the inner bundle is attached to the pubic crest
 +
Two views are thus entertained regarding the structure of the gubernacu]
 +
testis. According to one view it consists solely of plain muscular tissue ;
 +
connective tissue arranged as a cord within the peritoneal fold, called the p
 +
gubernatrix or plica inguinalis. According to the other view, in addition
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
74i
 +
 
 +
 
 +
ese fibro-muscular elements, there are superadded striated muscular fibres
 +
rived from the internal oblique and transversus abdominis muscles in the form
 +
 
 +
the inguinal cone. However constituted, the gubernaculum testis soon
 +
comes a stout thick cord, the final destination of which will be presentlyerred to.
 +
 
 +
The descent, or more properly the migration, of the organ commences before the
 +
ird month of intra-uterine life, and its usual destination is the corresponding
 +
•otal chamber. The migration is accomplished in four stages —pelvic, inguinal,
 +
;raparietal, and scrotal—and throughout all these stages it follows the lead
 +
the gubernaculum, which necessarily undergoes shortening.
 +
 
 +
The pelvic stage soon brings the testis into the iliac fossa, where it lies near
 +
3 brim of the true pelvis, having the epididymis laterally and the vas deferens
 +
idially, the latter dipping into the pelvic cavity.
 +
 
 +
The inguinal stage takes the testis to the posterior aspect of the inguinal
 +
rtion of the anterior abdominal wall at a point corresponding to the future
 +
ep inguinal ring, where it arrives about the sixth to seventh month.
 +
 
 +
Some time previous to this a path has been made for its further progress by
 +
3 formation of the inguinal canal and scrotal cavity. In the immediate
 +
inity of the lower or inguinal end of the gubernaculum testis a peritoneal
 +
 
 +
B C
 +
 
 +
Parietal A —-^— -- N ^
 +
 
 +
 
 +
 
 +
 
 +
Fig. 436. —Varieties of the Tunica Vaginalis.
 +
 
 +
A, normal type; B, congenital type; C, infantile type.
 +
 
 +
pression is formed, and the principal part of the inguinal end of the guberculum now slowly penetrates the Compact anterior abdominal wall in the
 +
?uinal region, thus giving rise to the inguinal canal and inguinal rings. In
 +
sparing this path for the testis, its gubernaculum takes with it the parietal
 +
ritoneum forming the peritoneal depression just alluded to, which accord?ly constitutes a peritoneal process, called the vaginal process. This process
 +
iy be likened to the finger of a glove, being open towards the peritoneal or
 +
dominal cavity, but closed at its distal end. The principal part of the guberculum lies behind the vaginal process, which latter aids the stout gubernaculum
 +
the formation of the inguinal canal.
 +
 
 +
As the vaginal process penetrates the inguinal portion of the abdominal wall,
 +
slongates before it the several elements which compose the wall in the following
 +
ler from within outwards :
 +
 
 +
1. Extraperitoneal areolar tissue.
 +
 
 +
2. Fascia transversalis.
 +
 
 +
3. Lowermost inguinal fibres of internal oblique muscle (cremaster).
 +
 
 +
4. External oblique aponeurosis.
 +
 
 +
5- Both layers - of anterior abdominal wall fascia (dartos muscle).
 +
 
 +
6. Skin of scrotum.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
742
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
In the foregoing manner the deep inguinal ring, inguinal canal, and su
 +
ficial inguinal ring are formed by the gubernaculum testis and vaginal proc
 +
Beyond the superficial inguinal ring these two structures enter the correspon<
 +
scrotal chamber, the lower part of the vaginal process forming a serous lining
 +
it. The lower part of the gubernaculum extends lower down than the lc
 +
end of the vaginal process, and this portion is attached to the fundus of
 +
scrotal chamber.
 +
 
 +
The intraparietal stage in the migration of the testis consists in the pass
 +
of the organ through the inguinal canal. This stage commences about
 +
seventh month of intra-uterine life, and the testis follows the lead of the mi(
 +
or principal bundle of the gubernaculum testis, gliding along the posterior ’
 +
of the vaginal process, and being post-vaginal in position.
 +
 
 +
The scrotal stage consists in the entrance of the testis into the corresponc
 +
scrotal chamber, which usually takes place about the end of the eighth mont
 +
intra-uterine life. The organ still lies behind the lower part of the vaginal proc
 +
which it invaginates from behind to form the tunica vaginalis. The middl
 +
principal bundle of the gubernaculum testis has now become very short, an
 +
ultimately represented by an indefinite fibrous bundle, spoken of as the remi
 +
of the gubernaculum, which connects the lower parts of the epididymis and te
 +
to the fundus of the scrotal chamber. The testis lies just outside the superfi
 +
ring during the ninth month, and descends to the fundus of the scrotum after bi
 +
 
 +
As the testis descends into the scrotum, the outer and inner bundles of
 +
gubernaculum testis, according to the view that there is a conus inguinalis,
 +
drawn downwards on the sides of the spermatic cord.
 +
 
 +
There are two theories regarding the migration of the testis, which may
 +
called developmental and muscular. According to the developmental the
 +
the migration is not an active process due to muscular contraction, but is brou
 +
about by developmental changes of the nature of disproportionate or unec
 +
growth, which take place in the lumbar, iliac, and inguinal regions of the tru
 +
According to the muscular theory, maintained by those who favour the existe
 +
of a conus inguinalis, the migration is brought about by muscular contractioi
 +
follows: All three bundles of the muscular inguinal cone would draw the te
 +
down to the mguino-pubic region and thereafter the middle bundle would di
 +
it down into the scrotal chamber, the outer and inner bundles being elonga
 +
downwards. The non-striated muscular fibres in the core of the gubernacul
 +
may also take part in the descent, and the descent may be aided by the ‘ reti
 +
tion of the connective tissue of the gubernacular core.
 +
 
 +
Female. The portion of the plica gubernatrix or plica inguinalis (of wh
 +
plica the embryonic inferior ovarian fold forms a part) between the caudal <
 +
of the ovary and the fusion of the para-mesonephric duct with its fellow to fc
 +
^ if- ^h e uterus represents the ligament of the ovary; and the p
 +
 
 +
which extends from the para-mesonephric fusion through the inguinal canal
 +
the labium majus contains the ligamentum teres of the uterus, which is
 +
homologue of part of the gubernaculum testis. In other words, the entire pi
 +
gubernatrix in the male contains the gubernaculum testis; whereas in the fern
 +
it pertains to (i) the ligament of the ovary, and (2) the ligamentum teres of
 +
uterus. The urogenital mesentery of either side, which is formed by the me
 +
vanum, mesonephric mesentery, and uro-genital fold (within which latter
 +
para-mesonephric duct lies along with the mesonephric duct) becomes the cor
 +
sponding broad ligament of the uterus (see p. 101).
 +
 
 +
Metamorphosis of the Vaginal Process. —As stated, the vaginal process
 +
originally a tubular process or diverticulum of the parietal peritoneum of 1
 +
inguinal region, resembling the finger of a glove, which precedes the descent
 +
the testis, and behind which the testis descends, following the lead of the mid'
 +
bundle of the gubernaculum testis. After the testis has reached the scro
 +
chamber it invaginates the vaginal process from behind to form the tun
 +
vaginalis, and that process now undergoes certain changes. To understa
 +
these changes, familiarity with the following facts is necessary: (1) The vagii
 +
process is closed below and open above; (2) the lumen of the process is sim]
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
743
 +
 
 +
 
 +
liverticulum of the cavity of the peritoneum; (3) the part of the process related
 +
the testis is called the testicular portion ; and (4) the part in front of the spermatic
 +
rd is referred to as the funicular portion.
 +
 
 +
The changes are as follows: (1) About the period of birth the vaginal process
 +
rally becomes constricted and closed superiorly at the deep inguinal ring,
 +
d then the process is an elongated tube, closed at each end, its lumen being
 +
w shut off from the cavity of the peritoneum. (2) A few days after birth the
 +
rcess usually becomes constricted and closed a little above the testis. (3) The
 +
iicular portion of the process usually becomes impervious and converted into
 +
ibrous thread, which as a rule disappears in the course of the first month after
 +
■th. (4) The testicular portion of the process persists as a shut serous sac,
 +
led the tunica vaginalis. Normally the persistent remains of the embryonic
 +
ginal process in the adult are (1) the testicular portion, which forms the tunica
 +
ginalis; and (2) a small nodule on the parietal peritoneum immediately behind
 +
3 deep inguinal ring. Instead of a mere nodule, however, a slender fibrous
 +
read, called the ligamentum vaginale, may extend downwards from this part
 +
the parietal peritoneum in front of the spermatic cord as low as the superficial
 +
;uinal ring, and sometimes as low as the tunica vaginalis.
 +
 
 +
In the female the vaginal process is represented by a tubular process of the
 +
ritoneum, which lies in front of the ligamentum teres of the uterus for a short
 +
stance in the inguinal canal. When this process remains open superiorly, it
 +
known as the canal of Nuck.
 +
 
 +
Abnormal Conditions of the Vaginal Process—Congenital Type. —(1) The
 +
 
 +
ginal process may remain permanently open throughout, under which circummces the cavity of the tunica vaginalis is in direct communication with the
 +
neral peritoneal cavity. (2) The vaginal process may be closed just above the
 +
nica vaginalis, but may remain as a permanently open tube above this point.
 +
Infantile or Funicular Type. —(1) The vaginal process may be closed only at its
 +
per end near the deep inguinal ring. In these cases the tunica vaginalis,
 +
stead of being limited to the region of the testis, is prolonged upwards as an
 +
ragated tube in front of the spermatic cord into the inguinal canal. (2) The
 +
ginal process may be closed above near the deep inguinal ring, and also below
 +
st above the tunica vaginalis, the portion of it intervening between these two
 +
ints remaining as an elongated tube, closed at either end, and lying in front
 +
the spermatic cord. (3) The vaginal process is sometimes closed at intervals
 +
mg the course of the spermatic cord, and when serous fluid accumulates in the
 +
tervening patent portions, the condition is known as encysted hydrocele of
 +
e cord.
 +
 
 +
Abnormal Positions of Testis. —(1) The testis may remain permanently in
 +
e abdominal cavity. (2) Its descent may be arrested in the inguinal canal, or
 +
the superficial inguinal ring. Such conditions constitute what is known as
 +
Jptor chism.
 +
 
 +
Ectopia Testis. —The testis may occupy unusual situations. (1) It may be
 +
jnd in the anterior part of the perineum. (2) It may be found on the front of
 +
e thigh in the region of the saphenous opening, in which cases it might simulate
 +
femoral hernia. (3) It may be found dorsal to the penis, in front of the symTsis pubis.
 +
 
 +
For the structure and development of the testis, see pp. 750 and 752.
 +
Extraperitoneal Tissue.—This is situated between the fascia trans:rsalis and the parietal peritoneum. Its condition is subject to
 +
uch variety, being fairly well marked in some bodies, and in others
 +
irdly perceptible. Medial to the external iliac vein at the inguinal
 +
lament it forms the femoral septum, which closes the upper end of the
 +
moral canal, and at the internal abdominal ring it is carried downirds round the spermatic cord underneath the internal spermatic
 +
ifundibuliform part) fascia.
 +
 
 +
 
 +
744
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
Parietal Peritoneum.—This is the innermost covering of the
 +
dominal wall, and it is connected with the fascia transversalis by
 +
subperitoneal areolar tissue. Behind the deep inguinal ring it forr
 +
slight projection, which in some cases enters the ring, the correspom
 +
depression on its abdominal aspect at this point being known as
 +
digital fossa. The projecting part of the parietal peritoneum co
 +
sponds with the upper end of the original processus vaginalis, and i
 +
be continued into a slender thread-like process, the obliterated upper ]
 +
of the processus vaginalis. It is here in the female that a divertici
 +
process may extend for a short distance into the inguinal canal in fi
 +
of the ligamentum teres of the uterus, forming the canal of Nuck.
 +
 
 +
 
 +
Umbilicus
 +
 
 +
 
 +
 
 +
Intermediate Inguinal Recess
 +
 
 +
 
 +
Medial Inguinal Recess
 +
 
 +
Fig. 437 -—The Folds and Recesses on the Posterior Surface of
 +
 
 +
the Anterior Abdominal Wall.
 +
 
 +
 
 +
Peritoneal Folds and Inguinal Recesses.—The peritoneum lining i
 +
posterior surface of the anterior abdominal wall below the umbili<
 +
presents folds and recesses.
 +
 
 +
The folds are five in number, one being situated in the middle li
 +
and two on either side. The median fold extends from the apex
 +
the bladder to the umbilicus, and contains the urachus. It is called 1
 +
median umbilical fold. Of the two lateral folds, the more medial c
 +
contains the obliterated hypogastric artery, and is called the late
 +
umbilical fold. It is oblique in direction, and meets the medi
 +
umbilical fold and its fellow of the opposite side at the umbilicus,
 +
corresponds to the junction of the inner two-thirds and outer thi
 +
of the inguinal triangle. The lateral of the two lateral folds is pi
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
7 45
 +
 
 +
duced by the inferior epigastric artery, and is called the fold of the
 +
inferior epigastric artery.
 +
 
 +
The inguinal recesses are six in number, three right and three left,
 +
and are called medial, intermediate, and lateral. The medial inguinal
 +
recess is situated between the median and lateral umbilical folds, and
 +
lies behind the inner two-thirds of the inguinal triangle, the conjoint
 +
tendon, and the superficial inguinal ring. The intermediate inguinal
 +
recess is situated between the lateral umbilical fold and the fold of the
 +
inferior epigastric artery, and lies behind the outer third of the inguinal
 +
triangle. The lateral inguinal recess is situated on the outer side of
 +
the fold of the inferior epigastric artery, and its lower and inner part
 +
is behind the deep inguinal ring.
 +
 
 +
 
 +
Inguinal Hernia.
 +
 
 +
By an inguinal hernia is meant a protrusion of a viscus (usually bowel, or,
 +
it may be, greater omentum) from the abdominal cavity in the inguinal region.
 +
This region is predisposed to such an occurrence from the presence of the two
 +
inguinal rings and inguinal canal, and the inguinal recesses. All forms of inguinal
 +
hernia, if complete, ultimately protrude through the superficial inguinal ring,
 +
and enter the scrotum. Relatively to the inferior epigastric artery there are two
 +
varieties of inguinal hernia—namely, lateral and medial, the former leaving the
 +
abdominal cavity lateral to that vessel, and the latter escaping medial to it.
 +
Inasmuch, however, as the region inside the inferior epigastric artery—namely,
 +
the inguinal triangle—is divisible into an inner two-thirds and an outer third,
 +
there may be two forms of medial hernia. Viewing, therefore, inguinal hernia in
 +
its relation to the abdominal wall, there are three varieties—namely, lateral
 +
oblique, medial direct, and medial oblique.
 +
 
 +
Lateral Oblique Inguinal Hernia. —This variety is called lateral because the
 +
hernia, as it leaves the abdominal cavity, is lateral to the inferior epigastric
 +
artery; and oblique, from its oblique course. The course of the hernia is as
 +
follows: it enters the lateral inguinal fossa, and stretches over it the peritoneum
 +
forming that fossa. It then passes through the deep inguinal ring, and traverses
 +
the entire length of the inguinal canal, from which it emerges through the superficial inguinal ring into the scrotum, thus forming a complete lateral oblique
 +
inguinal hernia. Throughout its entire course the hernia lies in front of the
 +
spermatic cord, and its descent is arrested at the upper part of the testis, which
 +
can be felt at its lower and back part. The bowel may be arrested at any part
 +
of the inguinal canal, the hernia being then called incomplete, and forming what
 +
is known as a bubonocele. In its descent the bowel elongates and carries before
 +
it certain investments from the structures to which it is related, these investments
 +
being called the coverings of the hernia. The first covering of this form of hernia,
 +
as of the other varieties, is derived from the parietal peritoneum, the particular
 +
part being that which forms the lateral inguinal fossa, and this constitutes the sac.
 +
the other coverings are simply those of the spermatic cord, which are all superadded to the sac. F
 +
 
 +
The coverings, enumerated in order from within outwards, are as follows:
 +
 
 +
1. Parietal peritoneum, which forms the sac.
 +
 
 +
2. Extraperitoneal tissue.
 +
 
 +
3 - Fascia transversalis, from the margins of the deep inguinal ring, forming
 +
 
 +
the internal spermatic fascia.
 +
 
 +
4 - Cremasteric fascia, at the lower border of the internal oblique muscle.
 +
 
 +
5 - External spermatic fascia, from the crura of the superficial inguinal ring.
 +
 
 +
6. Dartos muscle.
 +
 
 +
7 - Skin.
 +
 
 +
 
 +
 
 +
746
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
A short distance beflow the internal abdominal ring the subperitoneal fat am
 +
internal spermatic fascia become united, and are known as the fascia propria.
 +
 
 +
The sac is composed of the following parts: (i) the mouth, which is the openin
 +
by which its interior communicates with the general peritoneal cavity; (2) th
 +
neck, which is the constricted part immediately beyond the mouth; and (3) th
 +
body. The neck of the sac is on a level with the margins of the deep inguina
 +
ring, and the inferior epigastric vessels lie imrriediately on its inner side.
 +
 
 +
The seat of stricture may be (1) at the superficial inguinal ring; (2) at th
 +
lower border of the internal oblique muscle; or (3) at the neck of the sac, the las
 +
being the most common situation.
 +
 
 +
Medial Direct Inguinal Hernia. —This variety is called medial because th
 +
hernia, as it leaves the abdominal cavity, is internal to the inferior epigastrii
 +
artery; and direct, from its straight course through the abdominal parietes. Th(
 +
course of this variety is as follows: the hernia enters the medial inguinal fossa
 +
stretching over it the peritoneum forming that fossa. It then passes througl
 +
the inner two-thirds of the inguinal triangle, and so reaches directly the superficia
 +
inguinal ring without traversing the inguinal canal. Having emerged througl
 +
the superficial ring, it descends into the scrotum, thus forming a complete media
 +
direct inguinal hernia, which is in front of, and medial to, the spermatic cord
 +
It is to be noted (1) that there is no natural opening in the fascia transversali:
 +
over the inner two-thirds of the inguinal triangle, as there is external to thf
 +
inferior epigastric artery; and (2) that the conjoint tendon covers the inner two
 +
thirds of the inguinal triangle. The coverings of this variety, enumerated ir
 +
order from within outwards, are as follows:
 +
 
 +
 
 +
1. Parietal peritoneum.
 +
 
 +
2. Extraperitoneal tissue.
 +
 
 +
3. Fascia transversalis.
 +
 
 +
4. Conjoint tendon.
 +
 
 +
 
 +
5. Fascia triangularis.
 +
 
 +
6. External spermatic fascia.
 +
 
 +
7. Dartos muscle.
 +
 
 +
8. Skin.
 +
 
 +
 
 +
If the hernia occurs suddenly, rupture of the conjoint tendon may take
 +
place, in which cases the bowel would pass through the fissure. The seat of
 +
stricture in a medial direct inguinal hernia may be (1) at the superficial inguina]
 +
ring; (2) at the fissure in the conjoint tendon, if that structure should be ruptured;
 +
or (3) at the neck of the sac. The latter situation is the most common, and it
 +
is to be noted that the inferior epigastric vessels lie on the outer side of the neck
 +
of the sac.
 +
 
 +
Medial Oblique Inguinal Hernia. —This variety is called medial because the
 +
hernia, as it leaves the abdominal cavity, is medial to the inferior epigastric
 +
artery; and oblique, because it has to descend through the lower two-thirds of
 +
the inguinal canal. The course of this variety is as follows: the hernia enters
 +
the intermediate inguinal fossa, stretching over it the peritoneum forming that
 +
fossa. It then passes through the outer third of the inguinal triangle, and
 +
descends through the lower two-thirds of the inguinal canal, from which it
 +
emerges through the supeificial inguinal ring into the scrotum, thus forming a
 +
complete medial oblique inguinal hernia. Practically the only difference between
 +
the course of a medial oblique and a lateral oblique inguinal hernia is that the
 +
lateral oblique variety enters the inguinal canal by its natural inlet—namely,
 +
the deep inguinal ring—whereas the medial oblique variety obtrudes itself into
 +
the upper part of the inguinal canal through its posterior wall. It is to be noted
 +
(1) that there is no natural opening in the fascia transversalis over the outer
 +
third of the inguinal triangle, as there is external to the inferior epigastric artery;
 +
and (2) that there is no conjoint tendon over the outer third of the inguinal
 +
triangle. The coverings of this variety, enumerated in order from within outwards, are as follows:
 +
 
 +
1. Parietal peritoneum. 5. External spermatic fascia.
 +
 
 +
2. Extraperitoneal tissue. 6. Dartos muscle.
 +
 
 +
3. Fascia transversalis. 7. Skin.
 +
 
 +
4. Cremasteric fascia.
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
747
 +
 
 +
 
 +
If the coverings of a lateral oblique and a medial oblique inguinal hernia are
 +
compared with each other, it will be seen that the former has a tube of fascia
 +
;ransversalis already prepared for it—namely, the infundibuliform fascia—
 +
vhereas the latter has to elongate before it a fresh portion of fascia transversalis.
 +
[n some cases the fascia transversalis over the outer third of the inguinal triangle
 +
s covered by an expansion from the conjoint tendon, which is known as the
 +
nterfoveolar ligament. In such cases that ligament must be added as a covering
 +
)f medial oblique inguinal hernia, its position being immediately superficial to
 +
;he covering formed by the fascia transversalis. The relation of a medial oblique
 +
nguinal hernia to the spermatic cord is similar to that of a lateral oblique, and
 +
:he possible seats of stricture are also similar. The neck of the sac is the most
 +
common situation, and the inferior epigastric vessels lie immediately on its outer
 +
side. The extreme difficulty which must be experienced in diagnosing between
 +
i lateral oblique and a medial oblique hernia is explained by the fact that the
 +
former leaves the abdominal cavity immediately lateral to the inferior epigastric
 +
vessels, and the latter immediately medial to them. Hence, the practical rule
 +
followed in operating is to cut upwards and not transversely. The propriety
 +
of this rule is further enhanced if it be remembered that a lateral oblique inguinal
 +
hernia of old standing may so drag upon the deep inguinal ring as to displace
 +
it downwards and inwards to a point behind the superficial ring, and thus a
 +
hernia which is really lateral oblique may simulate one of the medial direct
 +
variety.
 +
 
 +
Varieties of Lateral Oblique Inguinal Hernia. —There are two varieties of this
 +
form of hernia, the special features of which depend upon abnormal conditions
 +
of the processus vaginalis (see p. 742). These varieties are named congenital
 +
and infantile.
 +
 
 +
Congenital Hernia. —There are two forms of congenital hernia. (1) The
 +
processus vaginalis may remain permanently open throughout, in which case
 +
the bowel descends within that process into the cavity of the tunica vaginalis
 +
at its lower extremity. The tunica vaginalis thus represents the sac of the
 +
hernia, and this form is therefore spoken of as a hernia into the tunica vaginalis.
 +
In such cases the bowel more or less completely envelops the testis. (2) The
 +
vaginal process may be shut off only just above the testis, the part above this
 +
remaining as a funicular process communicating above with the general peritoneal cavity. In such cases the bowel descends into the funicular process,
 +
which thus forms the sac of the hernia. This form is therefore spoken of as a
 +
hernia into the funicular process.
 +
 
 +
Infantile Hernia. —There are two forms of infantile hernia— infantile hernia
 +
proper and encysted hernia. In both there is a funicular process which is closed
 +
above towards the deep inguinal ring. It may also be closed below just above
 +
the testis, being thus distinct from the tunica vaginalis, or it may simply be
 +
an upward extension of the tunica vaginalis. In either case it is situated in
 +
front of the spermatic cord. In infantile hernia proper the bowel, having elongated
 +
the parietal peritoneum to form a sac, descends between the spermatic cord and
 +
the funicular process. Its importance consists in the fact that, before the
 +
bowel can be exposed in operating, three serous layers must be divided, two of
 +
these belonging to the funicular process and the other representing the wall of
 +
the hernial sac. In this form the descent of the bowel is arrested at the upper
 +
part of the testis. In encysted hernia the bowel, having elongated the parietal
 +
peritoneum to form a sac, pushes against the upper part of the funicular process
 +
so as to invaginate it in a downward direction in the form of a cup, in which
 +
the bowel, enclosed in its sac, lies. The condition of matters is therefore very
 +
much like an egg set in its cup, assuming that the top of the shell is removed,
 +
and that the wall of the cup is formed of two layers. To bring out this simile,
 +
the contents of the egg may be taken as representing the bowel, the shell of the
 +
egg being the sac of the hernia, and the assumed two layers of the wall of the cup
 +
representing the two serous layers of the doubled-down or invaginated funicular
 +
process, the cavity thus formed representing the inside of the cup. In this form,
 +
as m infantile hernia proper, three serous layers must be divided before the bowel
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
748
 +
 
 +
is exposed in operating, two of these belonging to the invaginated funicular proc(
 +
and the other representing the wall of the hernial sac.
 +
 
 +
Umbilical Hernia. —By an umbilical hernia is meant a protrusion of bovi
 +
or of greater omentum from the abdominal cavity in the neighbourhood of t
 +
umbilicus. The protrusion rarely occurs through the umbilicus, and is me
 +
frequent above the umbilicus than below. The coverings of an umbilical herr
 +
are as follows:
 +
 
 +
1. Parietal peritoneum.
 +
 
 +
2. Extraperitoneal tissue.
 +
 
 +
3. Fascia transversalis.
 +
 
 +
4. An expansion from the decussating fibres of the aponeuroses
 +
 
 +
of the abdominal muscles of opposite sides.
 +
 
 +
5. Superficial fascia.
 +
 
 +
6. Skin.
 +
 
 +
There is no vessel liable to be injured in operating on this form of hernia, t]
 +
inferior epigastric artery being about 1^ inches from the linea alba.
 +
 
 +
The congenital form of umbilical hernia (exomphalos) consists in a protrusic
 +
of bowel or omentum through the centre of the umbilicus into the umbilical cor
 +
in which it may descend for some distance? Its possible presence will show t]
 +
propriety of carefully examining the cord before ligaturing it after birth.
 +
 
 +
The anterior abdominal wall above the umbilicus has attached 1
 +
it posteriorly, an inch or so to the right of the middle line, an anter<
 +
posterior fold of parietal peritoneum, which represents a part of tt
 +
upper border of the falciform ligament of the liver. This fold contair
 +
at its lower margin a portion of the obliterated umbilical vein, the s(
 +
called ligamentum teres of the liver, which extends upwards from th
 +
umbilicus to the umbilical notch on the anterior border of the live:
 +
through which it passes to enter the fissure for ligamentum teres 0
 +
the under surface of the viscus. As the round ligament ascends to tb
 +
liver the peritoneum, within which it lies, is being gradually elongate
 +
in the form of two closely applied laminae, which form a part of th
 +
falciform ligament. The apex of this ligament is therefore at th
 +
umbilicus.
 +
 
 +
 
 +
The Tunica Vaginalis and Testis.
 +
 
 +
Tunica Vaginalis Testis.—This is a closed serous sac, behind whid
 +
the testis lies. It is formed by the lower part of the vaginal process
 +
or peritoneal diverticulum, which precedes the descent of the testi
 +
from the abdomen. Like all serous membranes, it is composed of tw<
 +
layers, parietal and visceral. The parietal layer is known as the tunict
 +
vaginalis scroti, from the circumstance that it lines the scrotal chambe:
 +
of its own side. It is much larger and looser than the visceral layer
 +
with which it is continuous along the posterior border of the testis
 +
and on the spermatic cord about | inch above the organ. The viscera
 +
layer closely invests the tunica albuginea of the testis, to which it is
 +
inseparably united. It also invests the epididymis except at its
 +
posterior border, where the constituents of the spermatic cord enter 01
 +
leave the testis. Between the epididymis and the testis it forms a
 +
recess, called the sinus of epididymis (digital fossa), and it extends
 +
upwards on the spermatic cord for about \ inch above the testis,
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
749
 +
 
 +
 
 +
Along the posterior border of the organ, where this layer becomes
 +
continuous with the parietal layer, there is a narrow strip which is
 +
free from serous investment. The portion of the tunica vaginalis
 +
which is related to the spermatic cord is called the funicular part.
 +
When fluid accumulates between the parietal and visceral layers, the
 +
condition is known as hydrocele of the tunica vaginalis.
 +
 
 +
Testis.—The testis is suspended obliquely by the spermatic cord
 +
in its scrotal compartment, to the bottom of which it is loosely attached
 +
by the fibrous remains of the gubernaculum testis. The left testis is
 +
a little lower than the right. The organ is oval, and compressed from
 +
side to side. Its exterior, which is smooth, is closely invested by the
 +
visceral layer of the tunica vaginalis, except where the constituents of
 +
the cord enter or leave the organ. The surfaces are lateral and medial,
 +
the former looking slightly backwards and the latter forwards. The
 +
extremities are superior and inferior, the former being inclined forwards
 +
 
 +
Spermatic Cord
 +
 
 +
Paradidymis
 +
 
 +
Parietal Layer of Tunica Vaginalis
 +
 
 +
Epididymis
 +
Sinus of Epididymis
 +
 
 +
 
 +
Fig. 438.—The Testis and its Coverings.
 +
 
 +
and the latter backwards. The borders are anterior and posterior.
 +
The anterior border looks slightly downwards and outwards, and is
 +
free. The posterior border looks upwards and inwards, and is attached.
 +
The average weight of the testis is about 7 drachms.
 +
 
 +
Epididymis.—This is an elongated narrow body, composed of the
 +
convolutions of the canal of epididymis, and lying along the posterior
 +
border and adjacent portion of the lateral surface of the testis. Its
 +
upper extremity, which is above the upper end of the testis, is enlarged,
 +
and is called the head (globus major); the lower and smaller end is
 +
called the tail (globus minor); and the intervening narrow portion
 +
represents the body. The head and tail are connected to the testis
 +
by fibrous tissue, and by a reflection of the tunica vaginalis, the former
 +
being further connected to the organ by the efferent ducts. The
 +
body, except at its posterior border, is free, being separated from the
 +
testis by the sinus of epididymis. The epididymis is completely invested by the visceral layer of the tunica vaginalis except at its posterior
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
750
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
border, where there is a duplicature of that membrane containin
 +
bloodvessels and attaching it to the testis.
 +
 
 +
Appendices Testis (Hydatids of Morgagni).—These are small pyramid;
 +
bodies which are situated on the anterior aspect of the head of epididym
 +
at its lower part, or on the front of the upper end of the testis belo’
 +
the head; they vary in position, number, and size; they may be pedunci
 +
lated or sessile. They are composed of connective tissue and blooc
 +
vessels, covered by the visceral layer of the tunica vaginalis, and ai
 +
to be regarded as vestiges of the mesonephros.
 +
 
 +
Paradidymis (Organ of Giraldes).—This organ is situated on tb
 +
front of the spermatic cord, immediately above the head of epididymi:
 +
and under cover of the funicular part of the tunica vaginalis. It cor
 +
sists of a few irregular nodules of convoluted tubules, lined with ciliate
 +
columnar epithelium. These nodules are remains of the mesonephros.
 +
 
 +
Arterial Supply of the Testis and Epididymis.—The testis derive
 +
its arterial supply from the glandular branch of the testicular (whic
 +
enters the posterior border of the organ), and the epididymis derives it
 +
supply from the epididymal branch of the testicular, which vessel arise
 +
from the abdominal aorta about I inch below the renal artery. Th
 +
tail of the epididymis also receives a few twigs from the artery to th
 +
vas, which is usually a branch of the superior vesical from the interne
 +
iliac.
 +
 
 +
The veins of the testis issue at the upper part of the posterio
 +
border, and, along with those of the epididymis, enter the spermati
 +
cord, where they form the pampiniform plexus. The right testicula
 +
vein, in which the right plexus ultimately ends, opens directly into th
 +
inferior vena cava, and the left into the left renal vein.
 +
 
 +
Lymphatics.—These ascend in the spermatic cord, and accompan;
 +
the spermatic vessels as high as the aortic groups of lumbar glands i:
 +
which they terminate. On the right side the glands to which the;
 +
pass lie in front of the inferior vena cava.
 +
 
 +
Nerve-supply.—The testicular plexus of the sympathetic system
 +
which derives its fibres from the aortic and renal plexuses.
 +
 
 +
The testis is homologous to the ovary of the female (testis muliebris)
 +
 
 +
General Structure of the Testis and Epididymis. —The testis is an aggregatio;
 +
of convoluted seminiferous tubules collected into lobes, which are encased withi;
 +
a capsule called the tunica albuginea. This tunic is a dense, bluish-white, in
 +
elastic membrane, composed of bundles of fibrous tissue. Its outer surface i
 +
closely covered by the tunica vaginalis testis. Its inner surface is invested by ;
 +
copious vascular network, known as the tunica vasculosa. At the posterio
 +
border of the testis the tunica albuginea passes for a certain distance into th
 +
interior, this inflection being called the mediastinum testis. This mediastinun
 +
extends into the organ for one-fourth of its antero-posterior measurement, anc
 +
fiom its sides and anterior border a number of septa, containing plain muscula
 +
tissue, pass off, which extend in various directions as far as the inner surface o
 +
the tunica albuginea, to which they are attached. By means of these the interio
 +
of the testis is mapped out into a number of lobes, the septa which enclose then
 +
containing the branches of the testicular artery as they make their way to th'
 +
tunica vasculosa. These compartments contain the convoluted seminiferou
 +
tubules collected into bundles called the lobes of the testis, which vary in numbe
 +
from ioo to 200. Each lobe contains from two to four tubules, and is conical
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
75i
 +
 
 +
 
 +
the base being directed towards the circumference of the testis and the apex
 +
towards the mediastinum. Each tubule is about 1 inch in diameter and is
 +
convoluted. When the coils are undone the tubule measures about 2 feet in
 +
length. The tubules of each lobule
 +
 
 +
 
 +
 
 +
Parietal Layer of Tunica
 +
Vaginalis
 +
 
 +
— Visceral Layer of Tunica
 +
Vaginalis
 +
 
 +
Tunica Albuginea
 +
Lobe of Testis
 +
 
 +
 
 +
Mediastinum Testis
 +
 
 +
[.Sinus of Epididymis
 +
- - Epididymis
 +
 
 +
Testicular Artery
 +
 
 +
 
 +
Vas Deferens
 +
 
 +
 
 +
! Testicular Veins
 +
 
 +
«
 +
 
 +
Artery of the Vas Deferens
 +
 
 +
 
 +
Fig. 439. —Diagram showing a Transverse
 +
Section of the Testis and Scrotum.
 +
 
 +
 
 +
unite into one, and the tubules of Wall 0 f Scrotum
 +
 
 +
adjacent lobules unite in turn, and
 +
so give rise to the straight tubules,
 +
each of which is about inch in
 +
diameter, and about ^ inch in
 +
length. These straight tubules
 +
enter the mediastinum, where they
 +
form by their division a network,
 +
called the rete testis. From this
 +
rete, tubules called efferent ducts
 +
proceed, which are about -fa inch
 +
in diameter, their number varying
 +
from twelve to twenty. These
 +
leave the testis at the upper part
 +
of its posterior border. For a short
 +
distance they remain straight, but
 +
they are soon thrown into convolutions, which form conical
 +
masses, called lobules of the
 +
epididymis. The length of each
 +
lobule of epididymis is about
 +
| inch, and its apex is directed towards the testis. When the convolutions
 +
are undone, the tube assumes a length of about 8 inches, its diameter
 +
gradually diminishing from about Aq inch at its commencement to about inch
 +
at its termination. The lobules open by separate orifices into the canal of the
 +
epididymis.
 +
 
 +
The epididymis consists of one tube, having a diameter of about ^ inch
 +
 
 +
in the head, where it commences in a blind extremity. In the body it
 +
diminishes a little in diameter, and in the tail it again
 +
enlarges. The tube presents a great number of
 +
convolutions, which, being
 +
folded upon themselves
 +
and connected together by
 +
loose tissue, give rise to a
 +
series of lobules. When
 +
the convolutions are undone the length of the
 +
epididymis has been variously estimated at from
 +
12 to 20 feet. At its upper
 +
extremity it receives the
 +
lobules, and beyond the
 +
tail it terminates in the
 +
vas deferens. At the point
 +
where it terminates in
 +
the vas deferens there is
 +
. a diverticulum connected
 +
 
 +
n it, called the aberrant ductules, which extend upwards in a convoluted
 +
anner between the epididymis and the adjacent part of the vas deferens,
 +
^e^th Grran ^ w ^ en coils are undone, is from 8 to 12 inches in
 +
 
 +
 
 +
Vas Deferens
 +
 
 +
Aberrant
 +
 
 +
Ductule
 +
 
 +
 
 +
 
 +
Head of Epididymis
 +
 
 +
 
 +
•"Lobules of Epididymis
 +
 
 +
 
 +
Body of Epididymis
 +
 
 +
 
 +
"Mediastinum Testis
 +
 
 +
 
 +
l—Lobe of Testis
 +
 
 +
 
 +
''Tunica Albuginea
 +
 
 +
 
 +
Tail of Epididymis
 +
 
 +
Fig. 440.—The Structure of the Testis and
 +
 
 +
Epididymis.
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
75 2
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
Minute Structure. —The convoluted seminiferous tubules are composed oj
 +
hyaline basement membrane, lining which there are several layers of epithel
 +
cells, (i) The most external layer consists of cubical cells, known as the parie
 +
cells. They line the basement membrane of the tubule, and are of two kirn
 +
The majority of them give rise to the spermatozoa, and these are called 1
 +
spermatogenic cells, or spermatogonia. Others are of a supporting nature, a
 +
are called the sustentacular cells, or cells of Sertoli, which subsequently form i
 +
columns of Sertoli. (2) The spermatogonia undergo mitotic division and gi
 +
rise to a second layer of cells, called the primary spermatocytes, or rnother-ce ,
 +
 
 +
(3) The primary spermatocytes a
 +
 
 +
 
 +
undergo mitotic division, and give rise
 +
a third layer of cells, called the seconds
 +
spermatocytes, or daughter-cells. T
 +
mitosis which the primary spermatocy
 +
undergo is of the heterotypical varie and results in the chromosomes present
 +
the secondary being half the number
 +
those present in the primary spermai
 +
cytes. (4) The secondary spermatocyi
 +
also undergo mitotic division, and gi
 +
rise to a fourth layer of cells, called t
 +
spermatoblasts, or spermatids. The
 +
spermatids, having undergone considi
 +
able modifications, give rise to the spi
 +
matozoa. These spermatozoa lie wi
 +
their heads buried between the me
 +
deeply placed cells, their long tails pi
 +
jecting free into the lumen of the tubu
 +
The enlarged ends or heads of the sp<
 +
Fig. 441.— Section through Semi- matozoa, whilst they lie buried betwe
 +
niferous Tubule (Magnified), the deeper cells, are connected with t
 +
showing Various Stages of sustentacular cells of the lining epitheliu:
 +
Development of Spermatozoa. The straight tubules are composed of
 +
 
 +
S, Sertoli cell; P, interstitial cells. basement membrane lined with a sin£
 +
 
 +
layer of cubical epithelium. The tubu]
 +
of the rete testis are destitute of a basement membrane, its place being taken 1
 +
the connective tissue of the mediastinum. The lining membrane of the tubu]
 +
consists of a single layer of cubical cells. The efferent ducts and the lobules
 +
epididymis are composed of a basement membrane, external to which there is
 +
layer of plain muscular fibres arranged in a circular manner. The lining epitt
 +
lium is of the ciliated columnar variety.
 +
 
 +
The structure of the epididymis is similar to that of the efferent ducts ai
 +
lobules.
 +
 
 +
 
 +
 
 +
Development of the Internal Sexual Organs.
 +
 
 +
A short account is given on p. 100 of the formation of the male and fema
 +
glands from the indifferent stage. In the testis are found medullary or sex cort
 +
composed of small epithelioid and large sex cells. Rete cords connect these wi
 +
the tubular structures of a part of the mesonephros.
 +
 
 +
Development of the Testis. —The medullary cords form cylindrical colum
 +
in which the cells slowly arrange themselves, so that lumina begin to appe
 +
in them about the seventh month. At the same time, or earlier, lumina a
 +
found in the rete cords, and by extension in each case those of the medullai
 +
and rete cords become continuous. Of the set of tubules formed in this wa
 +
those derived from the rete cords make the straight tubules and network of t]
 +
rete testis, while the larger parts, formed from the medullary cords, constitu
 +
the seminiferous tubules. The cells between the cords condense to form tl
 +
septa, continuous at the surface with the tunica albuginea. The tunica albugin
 +
is recognizable at a much earlier stage, half-way through the second monti
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
753
 +
 
 +
 
 +
development at this time ensures that, from now on, no further ingrowth
 +
cells from the surface layer can take place. Here and there, between the
 +
astomosing cell cords, are certain epithelioid cells, which seem to have been
 +
t off from the neighbouring cords; these are said to develop at a late stage into
 +
e interstitial cells of the testis.
 +
 
 +
The seminiferous tubes of the growing testis of later stages are lined by several
 +
^ers of cells, as described above. Spermatozoa remain quiescent in their
 +
sition up to the time of puberty, when, becoming motile, they free themselves
 +
d pass into the lumen, which has become considerably larger at this period.
 +
The structure and development of spermatozoa are dealt with on pp. 12 and
 +
, and the nuclear (reduction) changes on p. 17.
 +
 
 +
The convoluted canal of the epididymis, the vas deferens, and the ejaculatory
 +
,ct are developed from the mesonephric duct. The seminal vesicle is formed
 +
rly in the fourth month as a blind diverticulum of the caudal part of the
 +
ssonephric duct, and the aberrant ductule is a slender diverticulum of that
 +
irtion of the mesonephric duct which forms the tail of the epididymis; it is
 +
remnant of the mesonephros, as is also the paradidymis at a higher level.
 +
 
 +
Development of Ovary.—Medullary cords become apparent in the ovary at
 +
much later stage than in the testis, and are not so well defined, giving the imession of being little more than rudimentary formations. The same may be
 +
id of the rete cords, which, however, seem to be better formed, and even develop
 +
mina in some cases. The rete cords effect junction with the glomerular strucres of the neighbouring part of the mesonephros, at any rate in some instances,
 +
id are said to join also with the rudimentary medullary cords, but the whole
 +
t of structures is only of temporary existence. During the third month vessels
 +
ow into the hilum of the organ, and by their extension produce the appearance of
 +
complete septa within it. About a month later cells begin to invade the gland
 +
3m its covering ‘ peritoneal ’ cells, and this ingrowth displaces the rudimentary
 +
:ord ’ structures towards the hilum, where they ultimately break up and dis>pear. Ova are formed in the cells of the cords before the secondary ingrowth
 +
kes place from the surface, but when this occurs they degenerate, and ova
 +
e then derived from the ingrowing cells. Degeneration occurs even among
 +
ese, it being asserted, in fact, that the majority of ova degenerate after their
 +
rmation. It is not impossible that more than one invasion of cells may take
 +
ace from the surface, even during the first years of life, but nothing is certainly
 +
lown about this matter in the human subject.
 +
 
 +
In some animals the ingrowth from the surface takes place in the form of
 +
rds of celH, known as PfUiger’s cords, but this does not seem to be the case
 +
man, the appearance of such cords being produced only later by the aggredion of cells, which, being surrounded by indifferent cells as a tunic, make the
 +
-rly stages of the follicles of the ovary. Each follicle, then, contains cells derived
 +
Dm the surface, surrounded by indifferent mesodermal cells of the ovarian
 +
roma. One of the surface cells enlarges as the ovum, the rest, proliferating
 +
pidly, making the stratum granulosum and discus proligerus in which the ovum
 +
embedded, and also secreting the fluid (liquor folliculi) filling the follicle. The
 +
grounding stroma cells make the theca folliculi.
 +
 
 +
Development of the Epoophoron. —The horizontal tubule, which lies parallel
 +
the uterine tube, is a persistent part of the mesonephric duct, and represents the
 +
nal of the epididymis in the male. In some animals— e.g., the sow—the mesophric duct remains persistent, and, under the name of the duct of epoophoron
 +
drtner’s duct), can be traced from the broad ligament of the uterus along the
 +
le of that organ to the lateral wall of the vagina in its upper part, where it
 +
^appears. In the human female it sometimes takes a similar course, and the
 +
•rtion of it on the uterine and vaginal walls is to be regarded as representing
 +
e vas deferens in the male. The transverse tubules of the epoophoron, extend? from the region of the ovary to the horizontal tubule (so-called duct of epo'horon), into which they open at right angles, are vestiges of the anterior
 +
gmental tubes of the mesonephros, and represent the straight tubules, rete
 +
dis, efferent ducts, and lobules of epididymis of the testis in the male.
 +
 
 +
48
 +
 
 +
 
 +
 
 +
 
 +
754
 +
 
 +
 
 +
A MANUAL OF ANATOMY
 +
 
 +
 
 +
Development of the Paroophoron. —These vestigial tubules are derived i
 +
the more posterior segmental tubes of the mesonephros, and they represent
 +
paradidymis in the male.
 +
 
 +
 
 +
ABDOMINAL CAVITY.
 +
 
 +
The abdominal cavity is somewhat ovoid, the vertical meas
 +
ment greatly exceeding the transverse. Its superior boundary
 +
formed by the diaphragm, which here presents a concave surf
 +
The inferior boundary is formed by the levatores ani and coco
 +
muscles, covered superiorly by the visceral pelvic fascia and inferr
 +
by the anal fascia. This boundary is concave on its upper asp
 +
 
 +
 
 +
 
 +
 
 +
hie. 442 .—Diagrams to show Extent and Disposition of Abdominal Ca\
 +
from Reconstructions in Coronal and Sagittal Planes.
 +
 
 +
D, diaphragm; LA, levator ani; A, abdominal cavity; P, pelvic cavity; FP, 1
 +
pelvis; b, brim of pelvis, made by psoas major muscle.
 +
 
 +
I he superior and inferior boundaries, being fleshy, are capable of c
 +
tracting and relaxing alternately. During contraction the diaphra
 +
descends on each side and the levatores ani ascend, thus diminish
 +
the vertical measurement of the cavity. During relaxation the rev(
 +
takes place, the diaphragm ascending and the levatores ani descend]
 +
and so the cavity is increased in its vertical measurement,
 +
anterior and lateral boundaries are partly osseous and partly musci
 +
aponeurotic; the osseous boundaries are formed by the lower i
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
755
 +
 
 +
 
 +
>ove and the pelvis below; elsewhere these boundaries are formed by
 +
le musculo-aponeurotic planes of the abdominal muscles. The
 +
)sterior boundary is formed by the bodies and discs of the lumbar
 +
irtebrae, psoas major and quadratus lumborum muscles with their
 +
Lscial investments, the sacrum and coccyx. The cavity is divided
 +
ito two regions, the abdomen proper and the pelvis. The abdomen
 +
roper is limited below by the brim of the pelvis, and its visceral con:nts are the abdominal portion of the alimentary canal, with the
 +
tception of the pelvic colon and rectum; the liver, pancreas, spleen,
 +
idneys, and suprarenal bodies. The pelvis is situated below the level
 +
[ the brim, and contains the pelvic colon, rectum, and internal uromital organs.
 +
 
 +
Abdomen Proper.
 +
 
 +
Division into Regions.—The abdomen proper is divided into nine
 +
jgions by means of two horizontal and two vertical lines, with their
 +
Drresponding planes. The horizontal lines are called subcostal and
 +
itertubercular. The subcostal line encircles the abdomen proper on
 +
level with the lowest parts of the tenth costal cartilages, and the
 +
lane corresponding to it is called the subcostal plane. The interabercular line connects the tubercles of the iliac crests, which can
 +
sually be felt about 2 \ inches behind the anterior superior iliac spine,
 +
he plane corresponding to this line is called the intertubercular plane,
 +
he vertical lines are called the lateral lines, right and left, and each
 +
xtends vertically upwards from the centre of the inguinal ligament,
 +
'he subcostal and intertubercular lines, with their corresponding
 +
(lanes, map out the abdomen proper into three horizontal zones,
 +
ailed costal, umbilical, and hypogastric. The two lateral lines, with
 +
heir corresponding planes, subdivide each of these zones into three
 +
egionS'—two lateral, right and left, and a central. The abdomen
 +
>roper is thus eventually divided into nine regions, three in each of
 +
he three horizontal zones, as follows: the costal zone is subdivided
 +
nto right hypochondriac, epigastric, and left hypochondriac regions ;
 +
he umbilical zone is subdivided into right lumbar, umbilical, and left
 +
umbar regions ; and the hypogastric zone is subdivided into right iliac,
 +
lypogastric, and left iliac regions.
 +
 
 +
The regions just described and named are in general clinical use,
 +
md serve the purpose of allowing clinical description of location
 +
-vith great exactitude. Where more accurate placing is desirable, and
 +
n surface-marking of organs, it is customary to adopt the system
 +
ntroduced by Addison. This is a simple method, in which the whole
 +
trunk is halved and quartered horizontally, while vertical lines are only
 +
right and left lateral in addition to the median plane; here also the
 +
right and left lines are obtained by halving the distance between the
 +
tniddle line and the anterior superior iliac spine.
 +
 
 +
Fig. 443 shows Addison’s lines in position. The median plane is
 +
flanked by lateral lines, each half-way between it and the anterior
 +
superior spine. It is evident, therefore, that these lines do not corre
 +
 
 +
 
 +
75 ^ A MANUAL OF ANATOMY
 +
 
 +
spond with mid-Poupart lines. The transpyloric plane (TP) is half-w
 +
between the symphysis pubis and the suprasternal notch, dividi
 +
the trunk into upper and lower halves, each of which is again bisecti
 +
The upper plane (TT) gained in this way is the transthoracic, which
 +
 
 +
not used, being put in oi
 +
to complete the system. T
 +
lower plane (IT) is t
 +
intertubercular , extending 1
 +
tween the tuberculated pi
 +
minences on the iliac cre<
 +
it usually corresponds me
 +
or less with Cunninghan
 +
‘ intertubercular ’ plane, b
 +
is not obtained in the sar
 +
way, and should not be co
 +
fused with it.
 +
 
 +
It may be mentioned ht
 +
that the transpyloric plane is
 +
the level of the first lumt
 +
vertebral body. For clink
 +
purposes it can be found
 +
practice by taking a level ha
 +
way between the umbilicus ai
 +
the infrasternal notch—not t
 +
xiphoid cartilage; this is only
 +
way of getting the level witho
 +
exposure, but it is not the actu
 +
transpyloric plane, which is ha!
 +
way between the symphysis ar
 +
suprasternal notch.
 +
 
 +
Superficial View of tl
 +
Contents. — On taking
 +
superficial view of the coi
 +
tents of the abdomen prop*
 +
the sharp anterior border (
 +
the liver is seen on the rigt
 +
side projecting beyond th
 +
right costal margin, and als
 +
bulk of the organ, howevei
 +
lies concealed in the right hypochondrium, and the extent t
 +
which it passes into the left hypochondrium usually corresponds t
 +
the left mammary line. In the middle line it projects beyond th
 +
xiphoid process for about 2 inches, but along the right costal margi:
 +
it does not usually project more than about J inch. The anterio
 +
border presents two notches. One, which is well defined, is called th
 +
umbilical notch. It is situated fully i inch to the right of the middl
 +
line, and transmits the obliterated umbilical vein or ligamentum tere
 +
of liver. I he other, which is situated about 2 inches to the right of th<
 +
umbilical notch, is usually somewhat indefinite, and is called th<
 +
cystic notch. It allows the fundus of the gall-bladder to come forwarc
 +
 
 +
 
 +
 
 +
Fig. 443.
 +
 
 +
-Addison’s Lines on the Abdomen,
 +
 
 +
AS DESCRIBED IN TEXT.
 +
 
 +
 
 +
beyond the xiphoid process. The great
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
THE ABDOMEN
 +
 
 +
 
 +
757
 +
 
 +
 
 +
posite the ninth right costal cartilage at a point coinciding with the
 +
ter border of the right rectus muscle. The falciform ligament is
 +
nspicuous as it takes attachment to the supero-anterior surface of
 +
s liver, which it divides into two lobes, right and left.
 +
 
 +
On the left side a portion of the stomach is visible, though a large
 +
rt of the viscus lies deeply in the left hypochondrium. The portion
 +
lich is seen in the epigastrium is partially covered by the left lobe of
 +
e liver, but a part of it in contact with the anterior abdominal wall,
 +
ovided the viscus is not empty. Descending from the greater curva
 +
 
 +
 
 +
mall Intestine
 +
 
 +
 
 +
Gall Bladder
 +
Stomach
 +