Talk:Book - Buchanan's Manual of Anatomy including Embryology 11

ranches.— (i) Grey rami communicantes, which spring from the rlia. and pass to the anterior primary divisions of the sacral and ygeal nerves. These rami are very short. (2) Visceral branches nail size which pass from the upper part of the pelvic sympathetic l. (3) Parietal branches, which are distributed over the front of sacrum, and which communicate with those of the opposite side, s to form a plexus upon the median sacral artery. From the terminal 1 and ganglion impar (when present) branches proceed to the front tie coccyx and glomus coccygeum. The ganglia of the sacral trunk lot receive any white rami communicantes from the sacral nerves,

e, under the name of the pelvic splanchnics, going directly to the

dc plexus.

Levator Ani — Origin. —(1) The posterior surface of the body of the is in its lower part, below the attachment of the medial pubostatic or anterior true ligaments of the bladder, and above the ichment of the parietal pelvic fascia; (2) the internal surface of the ietal pelvic fascia along the arcus tendineus (white line) ; and (3) the dc surface of the spine of the ischium in its lower part, below the

ygeus.

Insertion. —(1) The side of the lower part of the coccyx; (2) the -coccygeal raphe, where it meets its fellow of the opposite side; the wall of the anal canal, where the fibres blend with the longiinal fibres of the gut, and ultimately pass with them between the srnal and internal sphincter muscles to be attached to the skin and the anus; and (4) the anal raphe and the perineal body, where muscle again meets its fellow of the opposite side.

The levator ani is a broad, flat, and thin fleshy muscle, the direc1 of which is downwards, inwards, and backwards; with its fellow he opposite side it forms an incomplete muscular floor to the pelvic ity. It is covered on its pelvic aspect by the visceral portion of the dc fascia, and on its perineal aspect by the anal fascia, and in this mer a separation is formed between one half of the pelvic cavity and ischio-rectal fossa of the same side.

The anterior border is free close to the body of the pubis, but a little her back it passes downwards upon the side of the prostate gland he male, or vagina in the female; farther back still it meets its fellow he opposite side, between the prostate gland and the commencement he membranous part of the urethra on the one hand and the rectum the other, or between the vagina in the female and the rectum, the Ting taking place in the anal raphe. Between the anterior borders

he two muscles the membranous part of the urethra in the male,

!• the vagina and urethra in the female, leaves the pelvic cavity. The erior or pubo-prostatic fibres are sometimes spoken of as the levator statae. The posterior border adjoins the coccygeus muscle.

The muscle is often divided on morphological grounds into two ts, the pubo-coccygeus and the ilio-coccygeus, the coccygeus muscle If constituting the ischio-coccygeus. The anterior fibres of the >o-coccygeus descend on the sides of the prostate gland and vagina,

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supporting these, and in strong contraction compressing them; posterior fibres of this part pass almost directly backwards, lying on i superior surface of the ilio-coccygeus muscle; but not all of these fib reach the coccyx, some ending immediately behind the anal canal joining the corresponding fibres of the opposite side to form the so-cal pubo-analis muscle. The ilio-coccygeus arises mainly from the ar< tendineus and the pelvic surface of the ischial spine, but its fibres cam infrequently be traced upwards underneath the arcus, particularly front, to become continuous with the outer surface of the upper part the parietal layer of pelvic fascia.

Nerve-supply. —(i) The anterior primary divisions of the third a fourth sacral nerve on its superior surface, and (2) the perineal brar of the pudendal nerve (deep division) on its deep surface.

Action. —(1) To elevate and support the floor of the pelvis, tl diminishing the vertical measurement of the abdominal cavity; (2) pull up the wall of the anal canal over the contained faeces, and so ass in their expulsion; (3) to pull the anal canal towards the symphy through the action of the pubo-analis muscle, and so straighten to soi extent this portion of the alimentary canal; (4) to elevate and compn the prostate gland in the male and the vagina in the female; and (5) flex the coccyx.

Coccygeus (Ischio-coccygeus) — Origin. —(1) The pelvic surface the spine of the ischium, above the origin of the posterior fibres of t levator ani; and (2) slightly from the inner surface of the parietal peh fascia, above the ischial spine.

Insertion. —The side of the upper two coccygeal and lower b sacral vertebrae.

Nerve-supply. —The anterior primary divisions of the fourth a: fifth sacral nerves.

Action. —To flex the coccyx.

The coccygeus is a thin, flat, triangular muscle, the fleshy fibi having a large admixture of tendinous fibres. The internal or peh surface is related to the visceral pelvic fascia, coccygeal plexus ai rectum, and the external surface to the sacro-spinous ligament. T superior border is adjacent to the pyriformis, with the intervention the structures which leave the pelvis below that muscle. The inferi border adjoins the posterior border of the levator ani. The muscle continuous with the sacro-spinous ligament, which is made by chang in its fibres.

The coccygeus muscle is to be regarded as a detached portion the levator ani.

The levatores ani and coccygei muscles form the pelvic diaphragm which presents a superior concave and an inferior convex surfac The greater part of this diaphragm is formed by the levatores ani, ar this part of it gives passage in the middle line to the rectum.

Pyriformis— Origin. — (1) By three fleshy slips from the anteri< surfaces of the second, third, and fourth sacral vertebrae, which a interposed between and lie lateral to the adjacent anterior sacr

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nina; (2) the deep surface of the sacro-tuberous ligament; and tie posterior border of the ilium immediately below the posterior ior spine.

nsertion. —An impression on the upper border of the greater troter of the femur near its centre.

Verve-supply. —Two branches from the sacral plexus, more Ocularly from the dorsal divisions of the first and second sacral es.

ction. —Lateral rotator of the thigh.

he intrapelvic portion of the muscle is covered by a prolongaof the parietal pelvic fascia, called the fascia of the pyriformis, it supports the nerves of the sacral plexus, branches of the anterior

ion of the internal iliac artery, and pelvic colon. For the extraic portion, see Gluteal Region.

Ibturator Internus. — Origin. —(1) The internal surface of the rator membrane; (2) the posterior surface of the body and inferior is of the pubis, and ramus of the ischium; (3) the inclined plane of ischium, extending as far back as the greater sciatic foramen, and ly as high as the iliac portion of the pectineal line; and (4) the stal pelvic fascia covering the muscle.

'nsertion. —The medial surface of the greater trochanter above and ont of the trochanteric fossa.

Verve-supply. —The nerve to the obturator internus from the sacral us.

1 ction. —Lateral rotator of the thigh.

Relations of Intrapelvic Part— Medial.— As low as the arcus tenus the internal surface of the muscle is covered by the parietal ic fascia and peritoneum with the extra-peritoneal areolar tissue, is directed towards the pelvic cavity. The obturator vessels and ie here lie between the extra-peritoneal areolar tissue and the etal pelvic fascia. Below the level of the arcus tendineus the Lial surface is still covered by the parietal pelvic fascia, which concts the pudendal canal. This portion of the muscle lies upon the ral wall of the ischio-rectal fossa. Lateral.— The internal surface the obturator membrane, and the surrounding bone. For the ‘a-pelvic part of the muscle, see p. 535.

Structure of the Viscera of the Male Pelvis.

The Bladder.

The wall of the bladder is composed of four coats serous, muscular, mucous, and mucous.

The serous coat is formed by the peritoneum, and is confined to superior surface and upper part of the base. It forms the false

ments of the viscus. . .

The muscular coat consists of plain muscular tissue, which is mged in three layers—external longitudinal, middle circular, and Tnal longitudinal.

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A MANUAL OF ANATOMY

The external longitudinal fibres are most apparent on the supei and inferior surfaces. Laterally they are scarce, and are dispo: in an interlacing manner. They have an independent bony atta ment to the posterior aspects of the bodies of the pubic bones n the lower part of the symphysis, where they constitute the so-cal pubo-vesical muscles. They then pass within the medial pubo-prosta ligaments to the prostate gland. Having covered the infero-late surfaces of the bladder as far forwards as the apex, some of them ; there prolonged along the median umbilical ligament for a short c tance, whilst others turn to the superior surface, over which they p to the base. Having descended upon the base, they enter the prost; gland, where they blend with its muscular tissue. The longitudi stratum has been called the detrusor urinse muscle from its suppos function in expelling the urine from the bladder.

The middle circular fibres are somewhat indistinct, and more less reticular over the greater part of the viscus. In the region wh the fundus and infero-lateral surfaces meet they become more distin and near the spot where the urethral opening is situated they forn tolerably well-marked annular bundle, known as the sphincter vesi( beyond which they are continuous with the muscular tissue of i prostate gland.

The internal longitudinal fibres are somewhat indefinite, and c chiefly recognizable on the inferior surface.

When portions of the mucous membrane project between 1 scattered muscular bundles, the bladder is said to be sacculated. Wh on the other hand, the muscular bundles become hypertrophied fr< any cause, such as enlarged prostate or stricture, they give rise inward projections of the mucous coat, which are arranged in a coarsi reticular manner, a condition known as the fasciculated bladder.

The submucous coat is situated between the muscular and muco coats, which it connects in a loose manner for the most part, and composed of areolar tissue with an admixture of elastic tissue, serves as a bed in which the arteries and nerves subdivide befc entering the mucous coat.

The mucous coat is soft in consistence, and of a pinkish colour health. It is continuous with the mucous membrane of the urete and urethra, and over the greater part of the empty bladder is thnn into folds, which, however, disappear as the viscus becomes distende This rugose condition is explained by the loose connection which exit between the mucous and muscular coats through means of the su mucous coat. Over the internal trigonum vesicae, however, to presently described, the mucous membrane is quite smooth, and al very sensitive. The mucous coat is covered by stratified transitior epithelium, similar to that of the ureters. In the most superficial lay the cells are cubical, and they present depressions on their deep si faces, which receive the round ends of the pyriform cells of the lay beneath. In the second layer the cells are pyriform, the round en being capped by the cubical cells of the first layer, and the narrow en

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deeply placed amongst the deeper cells. In the third and fourth

the cells are round or oval.

)rifices of the Bladder. —These are three in number—namely, ral, and two ureteric. The internal orifice of urethra is the ng by which the urine leaves the bladder, and it is situated at osterior extremity of the infero-lateral surfaces, where they meet ase. This is the most dependent part of the viscus, and is surled by the base of the prostate gland. Immediately above the ral orifice the mucous membrane presents a short median vertical , which projects forwards over the orifice. This ridge is called the vesicce. It is produced by the middle lobe of the prostate gland, 3 much more conspicuous when that lobe is enlarged. The ureteric ngs assume the form of small, slit-like, somewhat elliptical aper, which are about i| inches apart, and an equal distance from the aal orifice, their direction being obliquely downwards and inwards, ureters, before so terminating, have pierced the vesical wall uely, lying in it for about £ inch, and in this manner reflux of is prevented.

rigonum Vesicae. —This is situated at the lower part of the basal ce, and the mucous membrane over it is so closely connected to the ular coat that it is always smooth, and so presents a marked •ast to the rugose condition of the mucous membrane over the of the empty bladder. The trigone (Fig. 546) assumes the form 1 equilateral triangle, the angles of which correspond with the iral and ureteric openings, whilst the sides are constructed by s connecting these openings. The interureteric ridge, called ier’s bar, is produced by a bundle of muscular fibres, and is slightly ex, with the convexity directed downwards towards the urethral

e. The fibres constituting the ridge, on reaching the ureteric

es, run for some distance within Waldeyer’s sheath along and

3 rior to the ureter, with the longitudinal fibres of which they are lately continuous. When the fibres contract they pull the ureters iwards and inwards, increasing their obliquity, and thus diminishmy tendency to regurgitation of urine when contraction of the ier occurs; they moreover bring the duct more definitely within the 3 of the arched muscular fibres which surround the intraparietal ion of its course, and so still further diminish any such tendency, urethro-ureteric ridge on either side is also produced by a bundle of 'ular fibres, which are, however, very often indistinct, these bundles ^ known as the muscles of Bell. The uvula vesicae is situated at lower part of the trigone in the middle line above the urethral

e.

rtimen of the Empty Bladder. —This is very small, and is composed wo limbs, anterior and posterior. The anterior limb, which is , lies almost horizontally in front of the urethral orifice, and is ted by the juxtaposition of the superior and inferior walls. The ’rior limb, which is short, is directed upwards and backwards, and rmed by the juxtaposition of the back part of the superior wall

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and the base. The anterior and posterior limbs join each other at t urethral orifice, and are there continued onwards into the lumen the prostatic urethra. A triradiate appearance is thus impart to the lumen of the empty bladder and of the prostatic urethra, t three rays diverging from a central point—namely, the internal orifi of urethra—one ray being urethral and two vesical, of which latter o: is the anterior limb of the vesical lumen and the other the posted limb.

The Infantile Bladder. —The bladder in early life is pyriform. T narrow end is directed downwards, and is on a level with the upp border of the symphysis pubis, from which point it gradually descen as age advances. The broad end is directed upwards, and lies in t hypogastric region of the abdomen. The base is absent at this perio and the anterior surface of the viscus, devoid of peritoneum, is in co tact with the posterior surface of the anterior wall of the abdome which is likewise destitute of peritoneum. There being no base, t bottom of the recto-vesical pouch of peritoneum lies close to the ba of the prostate gland.

Ligaments of the Bladder. —These are classified as false and tri ligaments. The false ligaments are formed by the peritoneum, ai are five in number as follows: two posterior , which represent the laterall disposed lips of the mouth of the recto-vesical pouch; two lateral , rig] and left, which represent the reflection of the peritoneum from eac lateral border of the bladder to the corresponding lateral wall of tl pelvis; and superior , which is the reflection of the peritoneum from tl apex of the bladder to the posterior surface of the anterior abdomin wall along the median umbilical ligament. The true ligaments a: also five in number as follows: two lateral pubo-prostatic y right and lef which are formed by the vesical layers of the visceral portion of tl pelvic fascia on the sides of the bladder; two medial pubo-prostati which are the reflections of the visceral pelvic fascia from the back * the bodies of the pubic bones near the lower part of the symphysis i the neck of the bladder, and which pass in their course over the anteri< surface of the prostate gland; and superior , which is the median un bilical ligament. Each medial pubo-prostatic ligament contains son of the external or longitudinal muscular fibres of the bladder.

Blood-supply—Arteries. —These are as follows: (i) superior vesica from the umbilical artery; (2) inferior vesical, from the anterior divisic of the internal iliac; (3) vesical, from the intrapelvic portion of tl obturator; (4) vesical, from the intrapelvic portion of the inferior glutea and (5) branches from the uterine and vaginal arteries in the female.

Veins. —These are very copious, and are arranged in two plexusesvesical and prostatic. The vesical plexus is situated over the fundi and sides of the bladder, and its blood is conveyed into the prostat plexus. The prostatic plexus is composed of two parts continuous wit each other. Its blood is conveyed by one or more veins into the intern; iliac vein.

Lymphatics. —These pass to the external and internal iliac glands.

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erves. —Each half of the bladder receives sympathetic and spinal 3 from the following sources: (i) the pelvic plexus of the symetic, which contains spinal fibres from the third and fourth sacral es (sometimes also from the second), these being known as th epelvic ichnics ; and (2) special twigs from the pelvic splanchnics, which )e traced independently to the bladder. It is to be noted that the ler also receives spinal fibres from the upper two or three lumbar es through (a) the ganglia of the lumbar sympathetic trunk, (b) the c plexus, ( c ) the hypogastric plexus, and ( d) the pelvic plexus.

Structure of the Penis.

lorpora Cavernosa. —Each corpus cavernosum has a strong capsule, d the tunica albuginea. This tunic is composed of fibrous, plain

ular, and elastic tissues. It is disposed in two laminae—external

internal. The fibres of the external lamina are arranged longilally, and are common to both corpora cavernosa. The fibres of nternal lamina run circularly round each corpus cavernosum, and le middle line those of each side meet and are prolonged inwards septum, which is imperfect except near the roots of the penis, e* traversed by vertical clefts. This partition is called the septum, n the inner surface of the tunica albuginea strong trabeculae are n off, which penetrate into the interior of the corpus cavernosum. le trabeculae, which aie fibro-muscular and elastic in character, are nged in a reticular manner, and enclose the cavernous spaces of the tile tissue. The deep artery of penis lies in the centre, and, in tion to this chief vessel, several other arteries, derived from the al artery of the penis, enter it from the surface. The branches of e arteries run in the trabeculae, and terminate in capillaries, which

their blood directly into the cavernous or intertrabecular spaces,

e of the small arteries in the trabeculae are thrown into spiral loops,

h project into the intertrabecular spaces. Such vessels are called

helicine (spiral) arteries (Muller). From the intertrabecular spaces radicle veins proceed, and by them the blood is returned from the

in.

Corpus Spongiosum. —This differs from the corpora cavernosa in g destitute of any bony attachments. Its length is about 6 inches, it is expanded at either end. It is divided into a bulb, body, and s. The glans has been already described (see p. 713 et seq .) The bulb esents about the first i\ inches of the corpus spongiosum, and at widest part it measures § inch. It is surrounded by the bulbolgiosus muscles, and its enlarged posterior extremity rests upon the t of the inferior layer of the perineal membrane, where it is about ch in front of the anus. The body is cylindrical. It has a capsule unica albuginea, but this is very thin. Within the capsule there is erectile tissue, which resembles that of the corpora cavernosa, igh of a finer texture and not so well developed; in the centre is the igy portion of the urethra. The corpus spongiosum is traversed

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A MANUAL OF ANATOMY

by the arteries of the bulb, right and left, which are branches of 1 internal pudendal arteries. They are situated underneath the ureth canal, one on either side of the middle line.

The venous blood of the corpora cavernosa and corpus spongiosi is returned by the dorsal vein of the penis, and by the internal puden< venae comites.

For the structure of the different parts of the urethra, see p. 940

The glans penis and corpora cavernosa are developed from the genital ei nence, and the corpus spongiosum is developed from the genital folds.

Development of the Bladder and Urethra—The Allantois (see pp. 31, 32, s

45)-—The intra-embryonic part of the allantois is at first directly continu<

Dorsal Vein of Penis

Dorsal Artery of Penis

Dorsal Nerve of Penis

Septum

Skin

Dartos Muscle

Fibrous Sheath-- ■ of Penis

Fibro-elastic Capsule of Corpus Cavernosum

Deep Artery of Penis

Corpus Cavernosum

' _Corpus Spongiosum

Urethra

Arteries of Bulb of Penis

Fig. 554. —Transverse Section of the Penis of a Child as seen

under a Low Power.

with the upper part of the bladder, but in the course of the second month lumen usually disappears, and then this portion is transformed into a fibre cord, which is called the urachus. It is, however, to be noted that the lum of the intra-embryonic part of the allantois may remain persistent for soi time, thus giving rise to the condition which is known after birth as an umbilic urinary fistula.

The cloaca, which is the common terminal chamber of the hind-gut ai allantois (Fig. 555), is divided by the cloacal septum into ventral and dors parts. These changes are illustrated in the figure, where the dividing ‘ septun ib seen to deepen from above. The dorsal compartment gives rise to the rectui the ventral compartment constitutes the uro-genital sinus, so termed becau the excretory ducts and subsequently the genital ducts open into it.

These ducts are indicated in Fig. 555. The mesonephric (or Wolffian) due reach the lateral walls of the cloaca, and when the septum extends down behii

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m they are left opening into the dorso-lateral aspect of the ventral compartnt. Later, as will be shown in the next paragraph, the ureteric outgrowth m the duct comes to open into the cavity, and the ultimate opening of the duct t a lower level. Th e para-mesonephric (or Mullerian) ducts now reach this lower el by passing along the mesonephric ducts, and thus reach the uro-genital sinus ow the dilatation which forms the bladder.

In the meantime the cloacal derivatives are changing their form rapidly, e cloacal membrane (shown as a black line in the first two stages in Fig. 555) es cranially at first, but is quickly swung round so that it comes to face in opposite direction. This is brought about by rapid mesodermal formation men the base of the body-stalk ( BS) and the membrane, along the sides of which extends for some distance; in this way the genital tubercle (G) comes into dence, and the mesodermal growth beside the membrane makes the genital Is continuous with the tubercle. Thus not only is the area of the membrane mg round on its non-growing caudal extremity, but the whole mesodermal

Fig. 555.— Outlines to show Cloaca at Different Stages.

Observe rotation of plane of cloacal membrane and division of the cavity.

wth encloses a new cavity which is added to the length of the uro-genital sinus; 3 can be appreciated from Fig. 556.

The urinary bladder is developed from the cephalic part of this elongated '-genital sinus. In the first section in Fig. 556 the mesonephric duct (W) ches a dilated part of the sinus above the lower end of the septum (S). In the ond section the duct is not shown, but the marked elongation of the sinus, in ping with the great external growth, is well shown, and the dilatation of the dder is much more evident. Each duct had a metanephric bud (ureter) sning into it at first some distance from the sinus. The upper part of the sinus,

held by the lower thickenings of mesoderm, begins to expand, extending

n g the mesonephric duct in doing so; this expansion (Fig. 557) goes on round duct, the end of which is thus passively invaginated or intussuscepted into the dder cavity, where it rapidly atrophies, breaks up and disappears. This process s on until the expanding bladder reaches the ureteric opening, which is affected the same way, at its extreme end only, when the expansion ceases. Thus the ter comes to open into the bladder apart from the duct, and to its lateral side l above it.

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About this time the infra-umbilical portion of the belly-wall, hardly exist up to now, begins to grow, and the upper part of the sinus is gradually dra up with it; the lower part is, of course, fixed in the mesodermal condensatio Thus the bladder, carrying the ureter with it, is elongated in an upward directs The mesonephric duct, however, embedded in the topmost part of the cond sation, is held in position here. Thus its terminal piece, held below but dra up at its upper end, is embedded in and fused with the lining cells of the cor sponding wall of the sinus. This is indicated schematically in Fig. 558, wh the first diagram shows the dorsal wall of the sinus here including the end-piecf the duct (W), still visible almost as far as the level of the entrance of the ureter ( The next diagram shows how, by the breaking down of the (dotted line) vent wall of this included duct, its ultimate opening is left at the low level, while 1 ureteric opening is moving up. In this way the ejaculatory ducts come to oj below the level of the bladder.

Fig. 556. —Entodermal Cloaca of Embryos of 8-5 and 16 Mm., somewh

Schematized.

This part of the uro-genital sinus, in which the openings of the duct are k becomes the prostatic urethra or, in women, the whole urethra.

Membranous Urethra. —The membranous portion of the urethra is develoj from the caudal part of the uro-genital sinus.

Spongy Portion of Urethra. —The cloaca, the cavity (p. 45) common to 1 allantoic and intestinal terminations, is shut off from the exterior by the cloa membrane, consisting of entoderm and ectoderm, with a certain amount mesodermal cells between these layers. It extends at first from the tail pvoi nence to the body-stalk, and corresponds with the situation of the primitive stre> later it is more restricted in extent, being separated from the body-stalk mesodermal thickenings which make the genital eminence and the lower part the belly-wall, and from the tail prominence by a much smaller mesoderi growth which makes the ano-coccygeal region. The restricted area of cloa membrane, limited in this way, lies at the bottom of an external cloacal depress

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fossa, or ectodermal cloaca ; this is the cavity included between the external >odermal growths already mentioned. The internal or entodermal cloaca livided into rectal and uro-genital compartments in the course of the second

557.—Schemes to show how the Terminal Piece of the Mesonephric (Wolffian) Duct becomes invaginated within the Bladder as a Result of the Expansion of this Structure.

expansion finally involves the extreme end of the ureter, so that, when the invaginated parts disappear, the ureter and duct open separately into the cavity of the bladder.

Fig. 558.—Diagrams to illustrate Descriptions in the Text.

first two figures show the way in which the low level of insertion of mesonephric duct is gained. The third shows the curved uro-genital sinus, comprising the bladder dilatation (B); a pars pelvina (PP), into which the ducts (D) open; and a pars phallica (PPH), opening externally and prolonged on to the genital tubercle (T).

fih, and as this takes place a corresponding division of the external fossa )mes . apparent, due to a transverse mesodermal thickening—the perineal coinciding in position with the transversely disposed internal septum

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(which has divided the internal cloaca) as this completes its growth. The and outer transverse septa thus become continuous as the division of the ( is completed.

The part of the cloacal fossa behind the perineal fold forms the anal di sion or proctodaeum, and the portion of the cloacal membrane which for is called the anal membrane. When the anal membrane disappears (; the third month) the anus becomes formed, and the rectal compartment ( cloaca now opens into the back part of the cloacal fossa. The uro-genital opens into the cloacal fossa in front of the perineal fold by means of a n; vertical cleft, called the uro-genital cleft. Leading backwards from the gi eminence there is a furrow, which ends at the uro-genital cleft. The g< eminence is continuous at the sides with the labio-SCrotal folds, which, exte: backwards, enclose the cloacal fossa and the cloacal membrane. The pos surface of the genital eminence presents a groove, which is continuous wit uro-genital furrow. The lips of this groove, by their subsequent meeting fusion, form a canal, which represents the part of the spongy urethra cont in the glans penis. Posterior to this the lips of the uro-genital furrow together and unite as far back as the uro-genital cleft, and thus convert the part of the cloacal fossa into a canal, which represents the spongy part c

o

Fig. 559 -—Four Simple Outlines to show Closure of Urethra Development of External Male Characters.

R, raphe formed by fusion of genital folds (GF).

urethra behind the glans. The spongy part is thus to be regarded as a for extension of the uro-genital sinus, which opens at the uro-genital cleft. \ the lips of the uro-genital furrow fail to meet and unite at any part, the c( tion known as hypospadias is produced, in which the spongy urethra o externally on the under surface of the body of the penis. It is to be n that, whilst the prostatic and membranous portions of the urethra are devel from the ventral or uro-genital compartment of the entodermal cloaca, the sp portion is developed from the anterior part of the ectodermal cloacal fossa posterior part of that fossa giving rise to the anus and anal canal.

Structure of the Seminal Vesicles.

Each seminal vesicle consists of a tube which is thrown int number of coils, these being held together by fibrous tissue. W these coils are undone, and the tube straightened out, it measi from 5 to 6 inches in length. Its upper end is closed, and along course several diverticula are met. Each seminal vesicle in its nat sacculated condition is surrounded by a sheath, which is derived f the recto-vesical lamina of the visceral portion of the pelvic fae:

.

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in this sheath the tube has a fibrous wall composed of delicate is tissue, and within this there is a muscular coat, which is formed rin muscular tissue arranged in two layers—outer longitudinal nner circular. Within the muscular coat is the mucous coat, i presents a number of reticular ridges with intervening alveoli, ns bears a resemblance to honeycomb, in which respect it corre1 s with the mucous membrane of the ampulla of the vas deferens )f the gall-bladder, the last named having coarser meshes. The elium which covers the mucous membrane is of the columnar non?d variety.

ood-supply—Arteries. —These are derived from the inferior vesical, liddle rectal, the descending branch of the artery to the vas, and itrapelvic portion of the inferior gluteal.

tie veins are fairly large and numerous, and are disposed in a iorm manner. They communicate with the prostatic plexus, junphatics. —These go to the internal iliac glands.

Brves. —These are derived from the pelvic plexus.

ivelopment. —Each seminal vesicle is developed early in the fourth month liverticulum from the posterior or caudal part of the mesonephric duct, which the vas deferens originates. It begins to show dilatations at the e of this month.

Structure of the Ejaculatory Ducts.

he wall of each duct is composed of three layers as follows: an ' fibrous layer, which is very delicate; a middle muscular layer, >osed of an outer circular and inner longitudinal stratum; and an mucous layer, lined by columnar non-ciliated epithelium.

ivelopment. —Each duct is developed from the caudal part of the mesoic duct. The level of its opening is gained as described on p. 956 (Fig. 558).

Structure of the Prostate Gland.

he prostate gland is encased in a strong capsule, which is formed y by the visceral portion of the pelvic fascia, and partly by the tal pelvic fascia, in the following manner: the anterior wall of capsule is formed by the prostatic lamina, and the posterior wall ie recto-prostatic lamina, of the visceral portion of the pelvic 1; and on either side the capsule is joined by the corresponding of the superior layer of the perineal membrane (which is formed tie parietal pelvic fascia) after it has passed backwards over the ■ior border of the corresponding levator ani muscle. The capsule - material influence in fixing the prostate gland in its position. The ule is formed of concentric layers of fibrous tissue, within and een which lies the prostatic plexus of veins. The substance of the 1 is composed of two elements—muscular and glandular. The mlar tissue, which is of the plain variety, is arranged as (1) an mal, partly longitudinal and partly transverse layer, which lies

960

A MANUAL OF ANATOMY

beneath the fibrous capsule; and (2) an internal circular layer, wl surrounds the prostatic urethra, being continuous above with fibres of the sphincter vesicae, and below with those around the m branous portion of the urethra. Between these two layers the muse fibres pervade the gland in a decussating manner, so as to constru muscular reticulum, the meshes of which contain the glandular tis The chief part of the gland in front of the urethra is compose( muscular tissue. The glandular element consists of branched tub alveoli or acini, the walls of which are formed by a basement membi covered internally by columnar epithelium. The tubular alveoli into the prostatic ducts, the structure of which is similar to that ol gland-tubes. The ducts average twenty in number, ten on either 5 and they open by independent orifices upon the posterior wall of prostatic portion of the urethra, for the most part into the prost sinus on either side of the crest. The outer portion of the gk consists mainly of muscular tissue, and has received the name of a to distinguish it from the inner glandular portion—the medulla.

Blood-supply—Arteries. —These are derived from the inferior ves the middle rectal, and the intrapelvic portion of the inferior gluten

The veins form a copious prostatic plexus, which is most plen over the anterior and lateral surfaces. It receives in front the d( vein of the penis in two divisions, and discharges its blood by on more veins into the internal iliac vein. The prostatic plexus is li to become much enlarged in old age.

Lymphatics. —These pass to the external iliac, internal iliac, sa 1 and common iliac glands.

Nerves. —These are derived from the pelvic sympathetic plexus

Development. —The glandular part of the prostate is developed from epithelium of the uro-genital sinus. The epithelial cells in the course oj third month send out ramifying branches, which are at first solid, but si quently become tubular, and so form the glandular part. The outgro arise above and below the entrance of the mesonephric ducts, and from the of the urethra, and a small inconstant group may arise from its front 1 The muscular tissue develops during the fourth month from the surrour mesoderm.

Structure of the Rectum.

The wall of the rectum is composed of five coats—serous, fas muscular, submucous, and mucous.

The serous coat is formed by the peritoneum, and, as has 1 stated, is imperfect.

The fascial coat represents a sheath which is derived from visceral pelvic fascia. In front of the rectum it is composed of recto-vesical and recto-prostatic laminae, whilst posteriorly it is for by the rectal lamina of that fascia. It is best marked over the k third of the rectum, where the peritoneum is absent. Elsewhere comparatively thin, and over the peritoneal area it merges into subperitoneal areolar tissue.

The muscular coat is well developed, and is composed of p

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cular tissue, arranged as an external longitudinal and internal a lar layer. The longitudinal layer is present all round the gut, attains its greatest development along the anterior and posterior s, where it forms two broad stout laminae. Along the sides it is ewhat sparse. The circular fibres form a continuous covering for rectum, and inferiorly they become increased in amount around anal canal, and so give rise to the sphincter ani internus. rhe submucous coat is composed of areolar tissue, and connects muscular and mucous coats in a very loose manner, so that the sr is thrown into a number of temporary folds in the empty conm of the gut. The internal haemorrhoidal plexus of veins is >edded in this coat.

rhe mucous coat is characterized by great thickness and vascularity, ealth, therefore, it has a reddish colour, and is capable of free movet upon the muscular coat. The mucous membrane is covered by mnar epithelium, and is provided with crypts of Lieberkiihn and phoid nodules. It is thrown into a number of folds in the empty e, but the majority of these are temporary, and become effaced n the gut is distended. There are, however, at least three permanent s, which constitute the horizontal folds of rectum. The mucous ibrane is also studded over with a number of minute tubular dessions, called rectal pits, which are surrounded at their deep ends by phoid tissue (Birmingham).

rhe horizontal folds of rectum (Houston’s valves) are horizontal

ldings of the wall of the rectum in certain situations. Each fold is centic or semilunar, and consists of (1) the rectal mucous membrane, the submucous areolar tissue, and (3) a variable amount of the ular muscular fibres. The folds are very variable both in number position, but are usually described as three in number. The most stant and best-developed fold is situated on the right wall about ches from the anus on a level with the body of the fifth sacral vertebra the bottom of the recto-vesical pouch of peritoneum. It is there: related to the fundus of the bladder. This fold is sometimes referred is the plica transversalis recti, and is occasionally annular. The

al muscular fibres (circular) which it contains constitute the soed sphincter ani tertius, or sphincter of Nelaton. The other folds

much less definite, and are usually found one about an inch above the other about the same distance below the fold just described.

The horizontal folds are probably sustentacular in function, serving support the rectal contents. They may give rise to obstruction ing the introduction of instruments.

Structure of the Anal Canal.

The wall of the anal canal is composed of three coats muscular, imucous, and mucous. The muscular coat is composed of plain ocular tissue, arranged as an external longitudinal and internal ular layer. The longitudinal fibres are continuous with those of the

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A manual of anatomy

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rectum, and blending with them there are fibres of the ievator Inferiorly they pass between the internal and external sphincter be attached to the skin round the anus. Associated with the longitudinal fibres oil the posterior wall of the anal canal there an minute muscles (sometimes united into one), called the redo-coc muscles. These spring from the front of the coccyx and descend the posterior wall, where they blend with the longitudinal fibres.

There is nothing specially noteworthy in the submucous coat.

The mucous coat presents the anal columns and the anal va The anal columns (Morgagni) are six or more in number, and the form of permanent vertical folds, which are confined to the u two-thirds of the anal canal, where they are separated from each c

by longitudinal grooves. They composed of inflections of the mi membrane, which contain plain cular tissue belonging to the musci mucosae and small bloodvessels, stop short about § inch above the j T he anal valves are situated at lower ends of the anal columns a \ inch above the anus. They 1: the lower ends of the longitu* grooves, where they extend beb adjacent columns, and they be; resemblance to the valves which met with in veins. They are semil folds of the mucous membrane, ' free margins being directed upw; and above each valve there is a s recess or f sinus. 5 The anal valves sinuses are best seen in the child, tend to disappear as age advai The mucous membrane of the canal is replaced in the lower t (below the anal valves) by modified 5 and finally for the last few lines by ac skin with sebaceous glands and hair follicles; this skin in the neg pigmented like the skin covering the body, and terminates by joi the modified skin along a fine wavy line. In white races the junc is known as the white line of Hilton. In the upper two-thirds of canal the mucous membrane is lined by columnar epithelium , and in upper third it is provided with a few intestinal glands and lymp nodules. The wall of the lower third of the anal canal is linec epithelium, which gradually becomes more and more stratified as anal orifice is approached, and which is continuous at the anal ma with the epidermis. It is at the margins of the anal valves where modified epidermic epithelium gives place to the columnar epithel of the mucous membrane, and here also the modified skin of the k

Fig. 560. —Diagram of Structure of Rectum and Anal Canal.

L, C, longitudinal and circular fibres of wall : the circular fibres thicken below to form the internal sphincter (IS); ES, external sphincter; LA, levator ani.

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1 of the canal becomes continuous with the mucous membrane of ipper two-thirds.

phincter Ani Internus. —This so-called muscle is merely a thickenif the circular plain muscular fibres of the gut. It is confined to the >n of the anal canal, and viewing it as an independent muscle, or er thickening of muscular tissue, it begins very near the upper end Le anal canal, and terminates about \ inch above the anus. Though liary to the external sphincter, the principal action of the internal ncter is to expel the contents of the anal canal.

lood-supply of the Rectum and Anal Canal—Arteries. —The rectum and anal l receive their arterial supply from (1) the superior rectal, which is a single

1; (2) the middle rectals, right and left; (3) the inferior rectals, right and left;

[4) branches from the median sacral and inferior gluteal arteries, he superior rectal artery (superior hsemorrhoidal artery) is of large size, and e direct continuation of the inferior mesenteric. Having crossed the left non iliac vessels, it descends within the root of the pelvic meso-colon as is the third sacral vertebra, where the rectum commences. Here it divides two branches, right and left, which descend upon the sides of the rectum. 1 each of these divisions six or more branches are given off, which pierce ciuscular coat of the rectum about half-way down, and so enter the submucous in which they descend to lie ultimately within the anal columns. As these inal branches descend they give off twigs, which, by anastomosing with ches of the middle and inferior rectals, give rise to an arterial anastomotic ork in the submucous coat. The disposition of the two primary divisions e superior rectal artery on the sides of the rectum is to be borne in mind in )erformance of operations in this region.

t is important to bear in mind that while there is a free anastomosis between ower left colic arteries in the pelvic meso-colon, the anastomosis between the st branch of the lower left colic and the superior rectal is more restricted. a,ses, therefore, where it is desirable in the course of an operation to render pelvic colon more mobile by cutting through its mesentery, care should be n not to interfere with this low anastomosis, but instead to divide and tie 3r other of the upper branches of the lower left colic arteries.

•he middle rectal arteries (middle hsemorrhoidal arteries) are two in number, t and left, and are branches of the anterior divisions of the internal iliacs, 1 arising in common with the inferior vesicals. Having reached the sides ie rectum about its middle, they divide into branches, some of which supply muscular wall, whilst others enter the submucous coat to take part, along The superior and inferior rectals, in the anastomotic network.

"he inferior rectal arteries (inferior hsemorrhoidal arteries) are two in number, t and left, and each may be a single artery, or there may be two or three on side. In any case, they are branches of the internal pudendal, immediately

that vessel has taken up its position in the pudendal canal on the outer wall

ie ischio-rectal fossa. Having pierced the wall of the pudendal canal, and ersed the fat of the ischio-rectal fossa, they approach the wall of the anal T where they break up into branches, some of which supply the muscular , including the external sphincter and adjacent fibres of the levator ani, st others pass into the submucous coat, where they take part, along with the

nor and middle rectals, in the anastomotic network already referred to.

middle and inferior haemorrhoidal arteries of one side anastomose with F fellows of the opposite side.

he rectum also receives twigs from the median sacral and inferior gluteal ties.

feins. —The veins, all of which are destitute of valves, form two rich plexuses ternal rectal, situated in the submucous coat, and external rectal, lying § the exterior of the rectum, both being confined to its lower third. The

A MANUAL OF ANATOMY

964

internal rectal plexus, situated in the submucous coat, receives its radicles a set of vessels, termed anal veins, which commence beneath the skin of the c These anal veins ascend in the wall of the anal canal, some of them lying w the anal columns, and are reinforced by other veins from the anal wall. Ha given rise by their communications to the internal rectal plexus over the 1 third of the rectum, the blood is conveyed away from the plexus in two chai as follows: (1) the veins from the upper part of the plexus pierce the wall o: rectum, and open into the external rectal plexus; and (2) the veins from lower part of the plexus pass through the external sphincter to end in a pi on the outer surface of that muscle, in which the inferior rectal veins origii The external rectal plexus is situated on the outer wall of the rectum ove lower third, and is continuous below with the plexus on the outer surface ol external sphincter. It is from this external rectal plexus that the rectal v which correspond with the rectal arteries, arise. The superior rectal vein (supi hsemorrhoidal vein) leaves the plexus in two divisions, right and left, w ultimately join to form one vessel, the inferior mesenteric vein. It is there an indirect tributary of the vena portal vein. The middle rectal veins (mi hsemorrhoidal veins), right and left, terminate in the internal iliac veins. inferior rectal veins (inferior hsemorrhoidal veins), right and left, pass to internal pudic veins. Through means of the external rectal plexus a free ( munication is established between the systemic and portal venous channels, there being no valves, when the portal circulation is obstructed the condi known as haemorrhoids frequently results.

Lymphatic Vessels of Rectum, Anal Canal, and Anus—(1) Rectun

The lymphatics of the rectum can be divided into two groups, an up and a lower; the upper accompany the superior rectal vessels, after passing through small pararectal glands, which to the numbe four to seven lie directly on the muscular coat of the rectum underne its fascial covering, enter the glands in the pelvic meso-colon; the lo accompany the middle rectal vessels, and pass to a gland situated r the origin of the middle rectal artery.

(2) Anal Canal. —The lymphatics of the anal canal mainly acc< pany the inferior rectal vessels, coursing therefore below the levc ani, and draining into one of the internal iliac glands near the or of the internal pudendal artery; certain of them, however, upwards in the anal columns and join the lymphatics from rectum.

(3) Anus. —The lymphatic vessels of the anus pass to the superfi inguinal glands.

Nerves. —These are partly sympathetic and partly spinal, superior rectal artery conducts to the rectum and anal canal superior hsemorrhoidal sympathetic plexus, which is an offshoot fi the inferior mesenteric plexus, that in turn coming from the a0| plexus. The middle rectal arteries conduct the middle haemorrho sympathetic plexuses, which are offshoots from the pelvic plexus The spinal fibres are derived from the third and fourth sacral ner (sometimes also the second), and they belong to the pelvic splanchr They are further derived from the upper two or three lumbar ner all in the manner described in connection with the innervation of bladder. The fibres from the pelvic splanchnics carry motor impu to the longitudinal muscular fibres of the rectum and inhibitory pulses to the circular fibres; whilst the sympathetic fibres are moto

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ards the circular fibres, and inhibitory as regards the longitudinal res. The anal canal, close to the external sphincter, receives twigs m the inferior haemorrhoidal branch of the pudendal nerve.

Development of the Rectum, Anal Canal, and Anus.

In man the cloaca becomes partitioned off into two tubular compartments by Did, called the cloacal or uro-rectal septum. The two compartments or canals dorsal and ventral respectively. The dorsal canal gives rise to (1) the rectum, 1 (2) the upper two-thirds of the anal canal, or the part above the anal valves, s ventral canal leads caudalwards from the opening of the allantoic diverticulum, 1 is called the uro-genital sinus or canal. The allantoic diverticulum and

uro-genital ducts open into it.

The recto-anal and uro-genital canals are directed towards the cloacal mem,ne, which closes both of them ventrally and caudalwards. The uro-rectal turn is connected inferiorly with the cloacal membrane, and this membrane livided into two parts—namely, dorsal or anal, known as the anal membrane, 1 ventral or uro-genital.

The anal and uro-genital parts of the cloacal membrane are separated externj by a transverse fold, known as the perineal fold. This fold undergoes conerable thickening, and gives rise to the perineal body.

The anal membrane is soon sunk below the surface, producing thereby the il depression or proctodaeum. The depression consists of invaginated ectoderm ich meets the intestinal entoderm, and the two layers construct the anal memme, or anal part of the cloacal membrane. The condition of matters may be npared to the invagination of ectoderm, which forms the primitive oral cavity stomodaeum, and which, meeting with the entoderm of the pharyngeal part the fore-gut, forms the bucco-pharyngeal membrane.

The rupture of the anal part of the cloacal membrane gives rise to an aperture led the anus, through which the hind-gut and proctodaeum become continuous, e lower one-third of the anal canal—that is to say, the limited portion below i anal valves—is formed by the ectoderm of the anal fossa or proctodaeum. e time of disappearance of the anal membrane varies somewhat, but seems to usually in the third month.

In some cases the anal membrane—namely, that part of the cloacal memme which separates the hind-gut from the anal fossa or proctodaeum—is rsistent. Such a condition is known as atresia ani or imperforate anus.

The uro-genital part of the cloacal membrane becomes depressed, and so r es rise to the uro-genital fossa. When this part of the membrane ruptures,

5 uro-genital opening or Cleft is formed, by which the uro-genital compartment the cloaca—namely, the uro-genital sinus or canal—communicates with the terior.

THE FEMALE PELVIS.

The female pelvis contains the pelvic colon and rectum, with a few ils of the small intestine; the bladder and urethra; the uterus and gina; and the uterine appendages connected with the broad ligasnts—namely, the uterine tubes, the ovaries, with the epoophoron d paroophoron (the latter in early life); and the ligamenta teres of the erus. The arteries are the same as in the male, with the addition of •rtions of the ovarian arteries and the uterine arteries, and the subtution of the vaginal arteries for the inferior vesical arteries in the de. The venous plexuses are rectal, vesical, pudendal, ovarian, erine, and vaginal. The nerve-plexuses peculiar to the female are e uterine, ovarian, and vaginal.

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A MANUAL OF ANATOMY

General Position of the Viscera. —The pelvic colon and rectum

situated as in the male pelvis. The bladder lies anteriorly, b situated immediately behind the bodies of the pubic bones, and urethra is very closely related to the anterior wall of the vagina, virgin uterus lies upon the superior surface of the bladder, and the hi ligaments extend from either side of it to the lateral wall of the pe The vagina leads from the lower end of the uterus, and in its outv course lies between the base of the bladder and the rectum.

Peritoneum. —The peritoneum is related to the pelvic colon rectum as in the male. On leaving the rectum at a point fully 3 in above the anus it passes to the posterior wall of the vagina, whi( covers for about its upper fourth. It then mounts upwards over posterior surface of the supravaginal portion of the cervix uteri and

Fig. 561. —Female Pelvic Viscera seen from Above.

Ureter

Rectum

Sacro-gen. Fold Infundib. Pelvic Lig.

Ovary Uterine Tube

Round Ligament

body of the uterus. On reaching the fundus it turns round to anterior surface, which it invests as low as the junction of the b and cervix. On leaving the viscus it passes to the upper part of the 1 of the bladder, whence it extends forwards over the superior surf which it covers as far as the apex. Its later course is as in the rr Along each lateral border of the bladder the peritoneum is refle< on to the lateral wall of the pelvis. Along either side of the uteri is reflected on to the lateral wall of the pelvis, and in this manner broad ligaments are formed. Between the rectum and the upper ] tion of the posterior wall of the vagina and supravaginal portion of cervix uteri the peritoneum forms a recess, called the recto-uterine po (pouch of Douglas), which corresponds to the recto-vesical pouch in male. The mouth of this pouch is bounded on either side by a semilr peritoneal fold, which extends from the front of the sacrum over the

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the rectum to the cervix uteri. These folds are known as the rectorine folds (folds of Douglas) . Each fold contains a collection of fibrous i plain muscular tissues, connected on the one hand with the fibrous uctures in front of the lower part of the sacrum, and on the other

h the cervix uteri. They become continuous with each other over

»back of the isthmus uteri (junction of body and cervix), and there »y give rise to a transverse ridge, called the torus uterinus. The to-uterine pouch is bounded in front by the upper part of the posterior

1st Sacral Vertebra

Uterine Tube

Fundus Uteri

Bladder

Parietal Peritoneum

1st Coccygeal Vertebra

Symphysis Pubis

Urethra

Anterior Wall of Vagina , ; , Anal Canal

Anterior Fornix | R ec to-uterine Pouch Posterior Fornix

Fig. 562. —Vertical Sagittal Section of the Female Pelvis.

ill of the vagina and the supravaginal portion of the cervix uteri, and hind by the rectum. In front of the uterus the peritoneum gives >e to a small recess, called the vesico-uterine pouch, the entrance to tiich is bounded laterally by two folds, called the vesico-uterine folds. 5 regards the bladder, the peritoneum forms for it false ligaments as the male—namely, one superior, two lateral, and two posterior, tie latter are simply the vesico-uterine folds, and may be regarded not ily as posterior ligaments of the bladder, but also as anterior ligaments the uterus.

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A MANUAL OF ANATOMY

Pelvic Fascia. —The parietal pelvic fascia in the female is sim to the corresponding fascia in the male. The visceral pelvic fas however, is complicated by the interpolation of the vagina. On eit side of the pelvic viscera it divides into four laminae as follows: vesi which forms on either side the lateral pubo-prostatic ligament of bladder; vesico-vaginal , which passes between the bladder and vagina; recto-vaginal , which passes between the vagina and the rectr and rectal , which passes over the sides and posterior wall of the recti

Broad Ligaments of the Uterus. —These are also called the . vespertilionis , from their supposed resemblance to a bat’s wings. E; is an extensive fold of peritoneum composed of two layers, anterior c posterior, which pass between the side of the uterus and the late wall of the pelvis. The broad ligament has associated with it following important structures: (i) the uterine tube or oviduct, wh lies within the superior border of the ligament; (2) the ovary and ligament, which lie within a backward extension of the posterior la; of the broad ligament at a lower level than the uterine tube; (3) i ligamentum teres of the uterus, which lies within a forward project of the anterior layer of the broad ligament, also at a lower level tt the uterine tube; (4) the epoophoron, which lies within the ligam( between the ovary and the uterine tube; and (5) the paroophoron early life), which also lies within the ligament, medial to the epoophoi and near the uterus. The double fold of peritoneum attaching 1 anterior border of the ovary over its whole length to the back of 1 broad ligament forms a short mesentery for it, called the mesovariu which contains between its two layers the bloodvessels and nerves the ovary. The portion of the broad ligament which lies between 1 uterine tube and the ovary with its ligament is called the meso-salpi: It is somewhat falciform, and is narrow medially but broad lateral It is bounded above by the uterine tube, below by the ovary and ligament, medially by the uterus, and laterally by the ovarian limb and the suspensory ligament of the ovary.

Ligamentum Tere Uteri (Round Ligament). —This is a narrow, f band, about 5 inches long, which is attached to the upper part of t side of the uterus in front of, and a little below, the medial end of t uterine tube. It is composed of fibrous connective tissue, which m the uterus has an admixture of plain muscular fibres continuous w: those of the uterus. It lies within the anterior layer of the bro ligament, where it gives rise to a slight prominence. Its direction outwards, upwards, and forwards over the obliterated umbilical arh and pelvic brim to the deep inguinal ring, close to which it hooks rou the outer side of the inferior epigastric artery, and crosses the exteri iliac vessels from within outwards. Escaping by the deep inguii ring, it traverses the inguinal canal, and, emerging through the sup ficial inguinal ring, ends in the subcutaneous tissue of the labium maj For a short distance after entering the inguinal canal it is covered bj process of the peritoneum, which represents the processus vaginalis the male foetus. This process is at first tubular, and receives the na]

I

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the vestige of processus vaginalis (canal of Nuck). It is usually, yever, obliterated in the adult, though it may remain pervious, ler which circumstances the condition known as hydrocele of the mentum teres may occur. A few muscular fibres may be found in it of the ligamentum teres in the inguinal canal, which are conious with the lower fibres of the internal oblique, and represent the master in the male.

The ligamentum teres is supplied by two arteries as follows: the mentous branch of the ovarian artery, which supplies it as far as inguinal canal; and the ligamentous branch of the inferior epigastric,

Fundus

Cavity of Body of Uterus i

Ligament of Ovary

Uterine Tube

,Epoophoron

Cavity of Cervix ~4

External Os. (Anterior Lip)

Ostium Abdominale

Appendix Vesiculosa

Ovary

Ligamentum Teres of Uterus Broad Ligament

Fig. 563. —The Uterus and its Appendages.

A, the uterus opened, and the right broad ligament (posterior view);

B, the os uteri externum.

ich supplies it beyond the deep inguinal ring, and corresponds to cremasteric artery in the male. The principal venous blood is irned by a ligamentous vein, which is a tributary of the ovarian xus.

The ligamentum teres uteri represents the gubernaculum testis in ■ male.

Ovaries.—The ovaries are two small flattened bodies, each of which within a backward extension of the posterior layer of the broad tfnent, with which it is connected by the mesovarium. The ovary derally compressed, and usually lies with its long axis almost vertical, inclining a little downwards and backwards, against the lateral

97°

A MANUAL OF ANATOMY

wall of the pelvis in a peritoneal depression called the ovarian ft It may, however, lie obliquely, and may even be shifted, near to uterus. In size it may be likened to the half of a small walnut average length being from i inch to if inches, its breadth about f i: and its thickness (from side to side) from \ to \ inch. Its ave: weight is about 2 drachms. It presents two surfaces, two borders, two extremities.

The surfaces are laterally disposed, and are called medial , rel; to the uterine tube, and lateral, related to the ovarian fossa, borders are anterior and posterior. The anterior or mesovarian bo is straight. Along it are attached the two layers of the mesovan and between these it presents a hilum for the passage of the bli vessels, nerves, and lymphatics. The posterior or free border is cor and lies in close relation to the ureter. The extremities are na: ends (poles), superior and inferior respectively. The superior is na: the tubal end, because the ovarian fimbria is attached to it or nea Connected with it there is also a fold of peritoneum, which pa upwards to join the peritoneum over the psoas major near the u] part of the external iliac vessels. This fold, which is termed the pensory ligament of the ovary, or the ovario-pelvic ligament, is < tinuous with the outer part of the broad ligament, and contains ovarian vessels and nerves. The inferior end is known as the ute end, and is connected with the superior angle of the uterus by a io cord, called the ligament of the ovary, or the ovario-uterine ligam The attachment of this ligament to the uterus is behind and a 1 below the medial end of the uterine tube.

The surface of the ovary is covered by modified peritoneum, < tinuous with the mesovarium, the only exception being along anterior border, where the hilum exists. The connective-tissue elen of this peritoneum is inseparably blended with the so-called tu albuginea of the ovary, and it is covered by an epithelium the cel] which present a striking contrast to those of the endothelial cove elsewhere. It is composed of short columnar cells, and imparts a so what dull appearance to the surface, which contrasts with the polis appearance elsewhere. The ovarian epithelium is the remains of germinal epithelium, from which the ovary is developed, and at circumference of the organ it passes abruptly into the endothelial < of the adjacent peritoneum. Prior to puberty the surface of the o\ is smooth, but after that period it gradually assumes a pitted scarred appearance, which is due to the periodical escape of the from the vesicular ovarian follicles.

Descent of the Ovary. —The ovary, like the testis, originally lies in the lun region of the body-cavity by the side of the vertebral column. At this pe the inguinal fold, as stated, extends from the caudal end of the ovary to inguinal region, where it traverses the inguinal canal, and terminates within labium majus. As the ligament descends it becomes connected, as stated, ' the para-mesonephric duct at the level where this duct fuses with its fello’' form the uterus; the portion above the point of fusion becomes the ligamer the ovary, the portion below the ligamentum teres. About the third mont

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i-uterine life the ovary begins to descend towards the brim of the pelvis, ing arrived at the pelvic brim, it remains there for some time, and is still lat level at the period of birth. At a later period it descends into the pelvic ty as a rule, and assumes its normal position within a backward extension of broad ligament of the uterus.

rwo factors are probably concerned in the descent of the ovary—namely,

he shortening of that part of the inguinal fold which extends from the ovary

he side of the uterus close to the medial end of the uterine tube; and (2) the tion exercised by the fusion of the two para-mesonephric ducts to form the us and vagina.

(\.s each ovary descends, its mesovarium is taken along with it. This mesoum is intimately connected with the uro-genital fold, which contains the onephric and para-mesonephric ducts; and the uro-genital fold in turn is bined with the mesonephric ‘ mesentery ’ or ligament. The vestigial portions he mesonephros in the female are therefore carried down along with the sending ovary, these vestigial portions representing (1) the so-called duct of epoophoron or duct of Gartner, (2) the epoophoron, and (3) the paroophoThe combined mesovarium, uro-genital fold, and mesonephric ‘ mesentery ’ igament of each side become continuous medianly, and form one continuous it. Within this sheet the uterus is formed by the fusion of the two paraonephric ducts; each lateral part of the sheet constitutes the broad ligament be uterus.

Abnormal Positions of the Ovary. —(1) The ovary, in its original descent, r pass into the inguinal canal, and even into the labium majus; (2) it may 3 through the femoral ring into the femoral canal, and lie over the saphenous ning, where it may simulate a femoral hernia; (3) an ovary, when enlarged, / become prolapsed, and pass downwards and inwards behind the uterus ) the recto-uterine pouch, where it may be palpated through the posterior lix of the vagina.

For the structure and development of the ovary, see p. 980 et seq. Epoophoron.—The epoophoron is situated in that portion of the so-salpinx which lies between the ovary and the uterine tube. It is nposed of a number of small blind tubules, lined with epithelium, ich converge towards the ovary, but do not meet. Their tubal ends united by a longitudinal tube, which lies parallel with and a little ow the uterine tube, the duct of the epoophoron.

Paroophoron.—The paroophoron is situated in that part of the so-salpinx which lies between the ligament of the ovary and the !rine tube, where it is placed near the uterus. It is composed of a 1 minute blind tortuous tubules, which usually become shortly after th invisible to the naked eye.

For the development of the epoophoron and paroophoron, see

987. _

Uterine Tubes (Fallopian Tubes).—The uterine tubes, right and left, ve to convey the ova, after their escape from the vesicular ovarian Licles, into the cavity of the uterus. They are, therefore, functionally ' ducts of the ovaries, and are hence spoken of as the oviducts. Each is contained within the superior border of the broad ligament, except its extreme inner end, where the tube is embedded in the uterine wall, is fully 4 inches in length. Proceeding from the uterus, it passes at d horizontally outwards for about 1 inch towards the lower or uterine 1 01 the ovary. It then ascends vertically for a short distance upon 5 lateral wall of the pelvis, where it lies medial to the anterior or

97 2

A MANUAL OF ANATOMY

attached border of the ovary. Having arrived at the upper or ti end, it arches backwards and descends along the posterior convex bo and adjacent portion of the medial surface of the ovary. Each ute tube is divided into the following parts: pars uterina, isthmus, ampi neck, and corpus fimbria turn; and each has two openings, ost uterinum and ostium abdominale.

The pars uterina is the limited portion which is contained wi the uterine wall at the superior angle, and it presents the ost uterinum, which is about i millimetre in diameter. The isth succeeds to the pars uterina, and represents about one-third of tube. It is straight, round, and firm to the touch, due to the dominance of circular muscular fibres in this portion. Its diam is about 2\ millimetres. The ampulla succeeds to the isthmus, forms rather more than half of the tube. It is larger than theisthr less resistant (being chiefly mucous in structure), and tortuous, diameter gradually increases in the distal direction, the average b about 7 millimetres. The ampulla at its outer end becomes constri( to form the neck, which presents the ostium abdominale, opening the pelvic cavity, its diameter being about 2 millimetres. It is in situation where the general cavity of the peritoneum in the fema] continuous with the lumen of the uterine tube, and through it with cavity of the uterus and vagina. Beyond the neck the tube expa in the form of a funnel, called the infundibulum, near the centr which the ostium abdominale is situated. The circumference of infundibulum is broken up into a number of irregular fringes, ca fimbrice, and the outer end of the tube is hence called the corpus fiml turn. The larger fimbriae are broken up into smaller filiform proces The outer surfaces of the fimbriae, which look into the pelvic cavity, covered by peritoneum, but the inner surfaces, which look into infundibulum, are covered by mucous membrane continuous with 1 of the uterine tube. At the free margins of the fimbriae the peritone with its endothelial cells, becomes continuous with the mucous m brane, which is covered by ciliated columnar epithelium. One of fimbriae, which is larger and longer than the others, is called the ova\ fimbria, and is either directly connected with the upper or tubal of the ovary, or indirectly by means of a delicate fibrous band deri from and continuous with the broad ligament. This fimbria pres< a longitudinal furrow, which serves as a channel of communica between the ostium abdominale and the ovary.

For the structure and development of the uterine tubes, see p. <

Uterus.—The uterus is a hollow muscular organ, which receive: its superior angles the uterine tubes, and opens below through the up part of the anterior wall of the vagina. Through the uterine tube receives the ova at periodical intervals, and when an ovum becoi impregnated the uterus retains it during development, and therea expels the foetus through the vagina. The virgin uterus lies upon superior surface of the bladder, and is usually inclined to the righ the middle line. Above it there are a portion of the pelvic colon

THE ABDOMEN

973

jually a few coils of the ileum. At its lower end is the vagina, and le broad ligament stretches from either side. It is somewhat pyriform, le wide end being directed upwards and forwards, and is flattened

om before backwards. It is -m and resistant to the touch 1 account of its very thick uscular walls. Its average ngth is 3 inches, the breadth the upper part being 2 inches, id the thickness i inch. The gan is divided into a fundus, )dy, and cervix.

The fundus is that portion hich lies above the level of a le connecting the superior igles, where the uterine tubes iss through the uterine wall, is convex from side to side, d also from before backwards, le lateral borders of the erus are sloped downwards d inwards, and at the junction the upper two-thirds and ver third of the organ there a slight constriction or convity, called the isthmus, which also present in front and hind, and is most conspicuous early life. The part between s fundus and the isthmus is 3 body, and the part below s isthmus is the cervix.

Fig. 564. —Side View of Uterus and Upper Part of Vagina, to show Reflections of Peritoneum.

F, uterine end of tube; O, L, ovarian and round ligament; V, between the reflections of layers of broad ligament, marks region where branches of uterine artery enter the organ; SUS, suspensory ligament (Mackenrodt) ; UV, uterovesical fold; R, rectal fold; T, torus uterinus.

The body, which is 2 inches long, is triangular and presents two ooth surfaces, anterior and posterior, and two lateral borders. The terior or vesical surface, which has an inclination downwards, is flat slightly convex. The posterior or rectal surface, which has an inlation upwards, is very markedly convex. This difference in the flour of the two surfaces permits of their easy identification. Each wal border extends from the superior angle to the isthmus, and sloped downwards and inwards. The superior angles are situated the point of entrance of the uterine tubes, and correspond with ' portions of the uterus which are elongated into cornua in some mals.

The cervix, which measures 1 inch in length, is cylindrical, and rower than the body. It is received into the upper part of the erior wall of the vagina, the walls of which are attached to it in h a manner as to divide it into two portions—supravaginal and ravaginal. The posterior wall of the vagina extends higher upon the

974

A MANUAL OF ANATOMY

cervix behind than the anterior wall does in front. The antei surface of the supravaginal portion, which is about J inch in exte is related to the base of the bladder, with the intervention of so loose cellular tissue. The posterior surface of the supravaginal porti which is about J inch in extent, forms a part of the anterior wal] the recto-uterine pouch, and is crossed transversely by the to uterinus. At the lower end of the intravaginal portion, where cervix is slightly protuberant, there is an opening, called the exter os of uterus, through which the cavity of the cervix communica with that of the vagina. This opening is also known as the os tinea, cause it is supposed to resemble the mouth of the tench fish, on accoi of its lips being of unequal size. In early life this opening is circu but later, in the virgin, it assumes the form of a transverse slitab X2 inch long. It is bounded by two lips, anterior and posterior, wh in the virgin are smooth, but in multipart they are often more or ] fissured, especially the posterior lip. The anterior lip is thick, rou and short, whilst the posterior is thin, sharp, and long. The ante] lip descends lower into the vagina than the posterior, by reason of oblique manner in which the cervix uteri passes into the canal. I the anterior lip which first meets the finger in making vaginal exami tions. The greater length of the posterior lip is due to the fact that posterior wall of the vagina extends higher on the back of the cer than the anterior wall does in front. The external os is directed do) wards and backwards, towards the posterior wall of the vagina, i being due to the oblique position of the cervix.

Surrounding the vaginal portion of the cervix there is a vaul recess, which is divided into anterior, posterior, and lateral fornit In the region of the lateral fornix the ureter is situated f inch from cervix.

General Relations of the Uterus.—The anterior surface of the be rests upon the superior surface of the bladder, and the anterior surf of the supravaginal portion of the cervix is related to the base of bladder. The lateral relations are the uterine tubes, ligamenta tei ligaments of the ovaries, broad ligaments, and a certain amount adipose tissue, containing large bloodvessels, which lies upon either s of the cervix, and extends upwards over the lateral border between layers of the broad ligament. This collection is known as the pa metrium. The posterior surface of the body is related to the recti and the posterior surface of the supravaginal portion of the cer forms a part of the anterior boundary of the recto-uterine pouch.

Peritoneal Relations.—The following parts of the uterus are cove by peritoneum: the supravaginal portion of the cervix posterio: the posterior surface of the body, the fundus, and the anterior surf of the body as low as the front of the cervix. The following parts free from peritoneal covering: the intravaginal portion of the cen the supravaginal portion of the cervix anteriorly, and a narrow st along each lateral border where the two layers of peritoneum pass i to form the broad ligament. The uterine peritoneal folds are as folio

THE ABDOMEN

975

3 utero-vesical, sometimes called the anterior uterine ligaments, but

y may also be regarded as the posterior false ligaments of the bladder;

recto-uterine folds, with the torus uterinus; the ligaments of the

iry, the ligamentum teres on each side, and the broad ligaments. Position of the Uterus. —The virgin uterus occupies a position of

eflexion and anteversion, assuming the bladder and rectum to be

pty. In speaking of the uterus as being anteflexed it is to be underod that the body of the organ is bent forwards at the isthmus in

h a manner that it forms with the cervix an angle which is open

eriorly. This is brought about in the following manner

the cervix

Fundus

Cavity of Body of Uterus

Ligament of Ovary

Cavity of Cervix

External Os of Uterus (Anterior Lip)

Uterine Tube

v Epoophoron

Ostium Abdominale

' - Appendix Vesiculosa

Ovary

Ligamentum Teres of Uterus Broad Ligament

Fig. 565. —The Uterus and its Appendages.

A, the uterus opened, and the right broad ligament (posterior view);

B, the external os of uterus.

ri is more fixed than the body, from its connection with the vaginal

Us and base of the bladder; and the cervix is less yielding than the ly. In speaking of anteversion of the uterus it is to be understood it the entire uterus is inclined forwards, so that its long axis forms angle with the longitudinal axis of the trunk. The anterior surface 5 therefore a downward inclination towards the superior surface of

bladder, and the posterior surface has an upward inclination, and

supports a portion of the pelvic colon and a few coils of the ileum. ien the bladder is distended, the position of the uterus becomes ered. The organ is raised along with the distended bladder, the eflexion and anteversion become less, and the uterus may even

976

A MANUAL OF ANATOMY

assume a vertical position. Any coils of the ileum lying in con with its posterior surface, as well as the pelvic colon, would be displa and the organ would come to be closely related to the rectum.

Interior of the Uterus. —The interior is divided into two portior the cavity of the body and the cervical canal. The cavity of the l is very small compared with the thickness of the uterine walls, an triangular, with the base directed upwards towards the fundus, three sides are convex towards the cavity, and its anterior and poste walls are in contact. In the vicinity of each superior angle it narrc and gradually tapers to the medial end of the"uterine tube, with

Fig. 566. —Bladder, Vagina, and Rectum, exposed from the Right, show Peritoneal Reflections and Visceral Relations.

lumen of which it is continuous. Interiorly the cavity also becor narrow, and at the junction of the body and cervix it ends in a circu opening, called the internal os of uterus, which is smaller than external os. Through this opening it becomes continuous with cavity of the cervix. The canal of cervix is spindle-shaped, being wi< at the centre than at either end. It is somewhat flattened from bef< backwards, and is continuous above with the cavity of the be through the internal os, and below with the cavity of the vagina thror the external os. Its mucous membrane presents two longitude ridges, anterior and posterior, from each of which a number of ru

THE ABDOMEN

977

id in an upward and outward direction, the appearance thus prod being known as the arbor vita. The length of the cavity of the is is 2 \ inches, the difference between its length and that of the is, as measured externally, being due to the thickness of the fundus to the fact that the external os lies at the centre of a depression, ’terus at Birth. —At birth the neck of the uterus is larger than Dody, and there is no fundus. At each superior angle it tapers much, and resembles somewhat a uterus bicornis. The arbor extends all along the interior.

arieties. —These are as follows: (i) uterus bicornis; (2) uterus unicornis; 3) double uterus. These variations are due to the partial or complete perlce of foetal conditions.

'or the structure and development of the uterus, see pp. 983

V

r agina. —This is a musculo-membranous passage which extends t the cervix uteri to the vulva. It is from 3 to 3J inches long,

• 3 inches along the anterior wall and 3-J inches along the posterior.

slightly curved, and its direction is downwards and forwards,

ixis forms an obtuse angle with that of the uterus (ioo° to no°). re erect posture it forms with the horizontal an angle of about 6o°. iriorly it is closely connected with the cervix uteri, the posterior rising higher than the anterior. It is rather narrower at either than at the centre, the lower end being the narrowest part of the age. The walls are anterior and posterior, and they are in contact, ransverse section the vagina appears as an H-shaped fissure at its

r end, as a transverse fissure at the centre, while at its upper end it

ents a lumen which is almost circular.

■delations — Anterior .—The base of the bladder and the urethra. erior .—From above downwards there are the recto-vaginal pouch 1 short distance, the rectum, with the intervention of the rectonal lamina of the visceral pelvic fascia, and the anal canal, from

h it is separated by the perineal body. The posterior wall is

ired by peritoneum over about its upper fourth. Lateral .—The er at the upper end for a short distance, and the levatores ani cles.

rhe vagina passes through the perineal membrane, and its lower has a bulb of the vestibule on either side, with the bulbo-spongiosus ounding the external orifice. When the finger is passed into the terior fornix, which is the recess between the posterior lip of the irnal os of uterus and the posterior wall of the vagina, the rectoinal pouch can be palpated and a few coils of the ileum, or a prosed ovary, may be felt in it. The base of the bladder may be paled through the anterior fornix, and the urethra through the interior i of the vagina lower down. In the lateral fornices the ureters

Y be felt.

For the structure and development of the vagina, see p. 986. Bladder. —The base is directed backwards, and is related to the it of the supravaginal portion of the cervix uteri and a portion of the

62

A MANUAL OF ANATOMY

978

anterior wall of the vagina, the vesico-uterine pouch of the peritone intervening. The superior surface is in contact with the ante surface of the body of the uterus. The false ligaments formed by peritoneum are at least three in number—namely, one superior ; two lateral. The peritoneal folds on either side of the vesico-ute] pouch are usually regarded as the anterior uterine ligaments, but t may also be looked upon as the posterior false ligaments of the blad< The true ligaments are similar in both sexes.

Ureters. —Each ureter lies for a short distance on the side of cervix uteri and upper part of the wall of the vagina, being cros

antero-superiorly near the

vix from without inwards the uterine artery.

Urethra. — The urethra very closely related to the terior wall of the vagina.

length is ij inches, and

transverse diameter is ab J inch, the narrowest part be

at the external orifice, direction of the canal is do 1 wards and forwards, and walls are anterior and poster these being in contact exc during micturition. In course it passes between two layers of the perineal mi brane, where it is embraced the sphincter urethrae mus The canal is capable of c siderable distension, and m under anaesthetics, admit index finger. The external 1 fice of urethra is situated in middle line immediately in fr of the external orifice of vagina, and is placed on a sli prominence, the margins which are somewhat irregul;

For the structure and development of the urethra, see p. 987. Rectum—Relations — Anterior .—The uterus and vagina, the rec vaginal pouch intervening for a short distance in the vicinity of cervix uteri. Posterior .—As in the male.

Anal Canal. —This is separated from the vagina by the perir body.

Ovarian Artery in the Pelvis. —This vessel, which arises from abdominal aorta about 1 inch below the renal artery, enters the pe by crossing the commencement of the external iliac. It then pa*

Fig. 567. —Diagram to show Lateral Relations of Vagina, and of Ureter, etc.

THE ABDOMEN

979

in the broad ligament of the uterus, where it is very tortuous, and ranches to the ovary enter that organ through the hilum on the rior border without piercing the peritoneum. Besides supplying ovary, the vessel furnishes the following branches: uterine to the ns, near the superior angle, where it anastomoses with branches of iterine artery from the internal iliac; tubal to the uterine tube; and nentous to the ligamentum teres of the uterus, which it accompanies ir as the inguinal canal.

'he ovarian vein of each side originates as two vessels in the ovarian ampiniform plexus, which lies within the broad ligament. This us receives the veins which emerge through the hilum of the ovary,

Fig. 568. —The Ovarian, Uterine, and Vaginal Arteries (Posterior View) (after Hyrtl).

fell as tributaries from the uterine tube and the ligamentum teres he uterus, and it communicates freely with the uterine plexus, two ovarian veins, having emerged from the ovarian plexus, leave pelvis, and soon join to form a single vein, that of the right side ling into the inferior vena cava, and that of the left side into the renal vein.

Uterine Artery.— This vessel is derived from the anterior division tie internal iliac artery. It is directed downwards and inwards to side of the cervix uteri, near which it crosses the ureter. On reachthe cervix it turns upwards along the lateral border of the body in Ty tortuous manner, lying between the two layers of the broad

A MANUAL OF ANATOMY

980

ligament. As it descends it gives off tortuous branches to the front a back of the body, and near the inner end of the uterine tube it anas moses freely with the uterine branch of the ovarian artery. Along 1 side of the body it also gives offsets to the ligamentum teres ut< ligament of the ovary, and uterine tube. At the cervix the uter artery furnishes two branches—cervical and vaginal. The cervi branch supplies offsets to the cervix. One of these, called the coron> artery , divides into two branches, which with their fellows of the < posite side form an arterial circle around the cervix. The vagi branch divides into two, anterior and posterior, which descend in middle line of the anterior and posterior walls of the vagina, where tl anastomose with branches of the vaginal arteries.

The uterine veins, which are destitute of valves, form a copi< plexus within the broad ligament close to the uterus, where it is e bedded in the parametrium. The blood from the lower part of t plexus is conveyed away by two uterine veins, which are tributaries the internal iliac vein. A large proportion of the blood, howe\ passes from the upper part of the plexus into the ovarian plexus. 1 uterine plexus communicates below with the vaginal plexus.

Vaginal Artery. —This vessel, which usually replaces the infer vesical of the male, arises from the anterior division of the inter iliac, occasionally in common with the uterine or the middle rec artery. It passes downwards and inwards to the wall of the vagi where it divides into branches which anastomose with their felk of the opposite side, the vaginal branches of the uterine arteries, c towards the lower end of the vagina with branches of the inter pudendal. Along the anterior and posterior walls, in the median li an arterial chain is constructed by the vaginal arteries and the vagi branches of the uterine arteries, thus forming the vessels known as azygos arteries of the vagina. The vaginal artery also furnishes branc. to the bladder, rectum, and bulb of the vestibule.

The veins of the vagina form a rich plexus in the muscular cc which is more copious towards the lower end. They communic above with the uterine plexus, in front with the pudendal pie: around the urethra, behind with the rectal plexus, and below with veins of the bulb of the vestibule. The vaginal vein leaves the up part of the vaginal plexus and opens into the internal iliac vein.

The Structure of the Special Viscera of the Female Pel 1

The Ovaries.

The ovary is covered by a layer of short columnar epithelial c< These are the remains of the germinal epithelium from which organ is developed, and they rest upon a delicate connective-tk membrane, which is blended with the so-called tunica albugir Interposed between the columnar cells there are a few spheroidal c of larger size, which are primordial ova. The connective-tissue m

THE ABDOMEN

981

e is continuous with the peritoneum, which forms the mesovarium y the margins of the hilum, and is covered by endothelium. Within membrane, and blended with it, there is a continuous covering, isting of fibrous connective tissue, which is called the tunica albu1, from its supposed resemblance to the tunica albuginea of the s. It is, however, really a condensation of the ovarian stroma at surface. This stroma pervades the interior of the ovary, and is Dosed of fibrous connective tissue, which is richly provided with lie-shaped cells and elastic tissue. There are also a few plain

ular fibres in the deeper part of the ovary close to the hilum. The

lie-shaped cells are regarded by some authorities as muscular fibre, but they probably belong to the connective tissue of the stroma, stroma is freely permeated by bloodvessels, and contains the nilar ovarian follicles. Immediately within the surface there is a

Small Ovarian Follicles Mature Ovarian Follicle

Ovarian Stroma

Fig. 569.—Section of the Ovary, showing its Minute Structure.

r of the stroma which presents a granular appearance, especially in ig persons, due to the presence of an immense number of ovarian

les, with their contained ova, in an early stage. This part of the

y is called the cortex, the remainder being known as the medulla.

ig more deeply in the stroma there is another set of ovarian follicles, numerous but of larger size, these being in a more advanced stage, more deeply there is another and less numerous set of follicles, of larger size, which are almost in a state of maturity. When these sr have attained full development they pass towards the surface, re they may sometimes be seen as clear follicles causing slight proions. When fully developed, they attain a diameter of about ich. At periodical intervals one or more of these mature follicles ture, this being accompanied by the discharge of a fluid—the liquor culi—and the simultaneous escape of the contained ovum or ova. ir the discharge of its contents the follicle becomes filled with blood

982

A MANUAL OF ANATOMY

and cellular tissue, and assumes a yellow colour. It is then known a corpus luteum. This undergoes atrophy in the virgin, and, assumi a white colour, is known as a corpus albicans.

Structure of the Vesicular Ovarian Follicles (Graafian Follicles). The smallest follicles near the surface, which are about inch diameter, consist of a single investing layer of flattened cells clos< embracing the contained ovum. It is computed that the ovaries 0 child at birth contain as many as 70,000 of these follicles. In follic a little more advanced the investing epithelium becomes column and is arranged in two layers—outer and inner, the latter surroundi the ovum. In more mature follicles fluid, called the liquor follioi accumulates between the outer and inner cellular layers, except at 1 point where the ovum lies. The outer layer is then known as i membrana granulosa, and the inner as the discus proligerus. The c( of these two layers became continuous at the part* where the liqi folliculi is absent, so that in this manner the ovum is anchored to c point of the wall of the follicle. In the most mature follicles the liqi folliculi has increased in amount, and the cells of the membrana grai losa and discus proligerus have multiplied so as to form several stra Each of these follicles has a distinct wall, called the theca folliculi , wk is formed by a condensation of the surrounding stroma, and in whi two layers can be recognized—an outer fibrous and an inner vascul There is usually only one ovum in each follicle.

For structure of the ovum, see p. 14.

Blood-supply of the Ovary. —The ovary receives its blood from t ovarian artery.

Nerves. —These come from the ovarian sympathetic plexus, wh derives its fibres from the renal and aortic plexuses, and accompan the ovarian artery.

Lymphatics. —The lymphatic vessels of the ovary accompany 1 ovarian bloodvessels, and terminate in the juxta-aortic glands on eitl side. They are joined by most of the lymphatics of the body of 1 uterus and by those of the uterine tube.

The ovaries represent the testes in the male, and they have b< called the testes muliebres.

Ligament of the Ovary. —This is composed of plain muscular 3 fibrous tissues, the former being continuous with the muscular tis of the uterus. It derives its blood-supply from the ovarian art' and represents the upper part of the gubernaculum testis in the mj foetus.

Structure of the Uterine Tubes.

The wall of the uterine tube is composed of four coats—sere muscular, submucous, and mucous. The serous coat is formed the peritoneum. The muscular coat is composed of plain mused tissue arranged as an outer longitudinal and inner circular layer, latter being the thicker. The submucous coat is areolar in structi The mucous coat is continuous with that of the uterus on the one ha)

THE ABDOMEN

983

with the peritoneum on the other at the margins of the fimbriae. 3 thrown into longitudinal folds, which are simple in the isthmus, complex in the ampulla, where they are beset with secondary folds, communicate in such a manner as to give rise to alveolar spaces, 3 imparting an almost glandular appearance to the coat. In trans>e section the tube presents a branched lumen, which is nearly filled the leaf-like processes formed by the mucous folds. The mucous nbrane is covered by ciliated columnar epithelium, which, at the

margins of the fimbriae, passes into the endothelium of the perieum.

Blood-supply. —The ovarian and uterine arteries.

Fig. 570. —Transverse Section of the Uterine Tube (magnified).

Nerves. —These are derived from the ovarian and uterine sympadic plexuses.

Lymphatics. —These pass to the median lumbar glands along with )se of the ovary and upper part of the body of the uterus.

Structure of the Uterus.

The wall of the uterus consists of three coats—serous, muscular, d mucous—there being no submucous coat.

The serous coat is formed by the peritoneum, already described. The muscular coat is composed of plain muscular tissue, with an mixture of areolar tissue, and it imparts great thickness to the wall. ie muscular tissue is disposed in three strata- outer, middle, and ler. The outer stratum is thin, and its fibres are disposed longitudinally

984

A MANUAL OF ANATOMY

over the front and back of the organ, becoming continuous with ( another by turning over the fundus. Those nearest the lateral bord incline outwards, and are prolonged into the ligamenta teres, uter tubes, and ligaments of the ovaries. Some from the back of the sup vaginal portion of the cervix are prolonged into the recto-uterine fol The middle stratum is very thick, and is composed of fibres which int lace in a complex manner over the body, but in the neck they ; arranged circularly. The bloodvessels and nerves are freely int spersed throughout this layer. The inner stratum , which is also v<

Fm. 571. —Upper Figure, Diagram to show Composition of Uterine Wa:

M, muscular wall. The lower sections show on the left a piece of premenstr mucosa; on the right one from an early pregnancy. The stroma-cells ; enlarging, and in the last specimen are very evident as decidual cells.

thick, has its fibres disposed longitudinally in the cervix. As th ascend over the body they become oblique, and at the superior ang they run circularly. The uterine glands project into this stratuj and it contains a free admixture of areolar tissue. It is right to menti that the inner stratum is regarded as a very much thickened muscula mucosae, according to which view it would form a part of the muco coat (Williams).

The mucous membrane of the cavity of the body is smooth, and sc in consistence, and is covered by ciliated columnar epithelium. Itj

THE ABDOMEN

985

t with a number of openings, which are the mouths of the uterine tricular glands. These are simple tubular glands, which extend somewhat convoluted manner through the entire thickness of the ous coat, and project by their deep blind ends into the inner cular stratum, there being no submucous coat. Each gland is posed of a basement membrane, which is lined with ciliated mnar epithelium, continuous with that of the cavity of the body, h has a distinct lumen, except at its deep end, where it is filled l cells. The mucous membrane of the canal of cervix is of firmer dstence than that of the cavity of the body, and, as has been stated, resents the appearance known as the arbor vitae. It is provided 1 papillae, and is covered olumnar epithelium, except - the os externum, where epithelium is of the stratisquamous variety, like that sring the intravaginal porof the cervix and lining vagina. On the summits he rugae the columnar cells ciliated, but in the furrows veen them they are devoid cilia. The mucous mem(ie is freely provided with smose glands, which in the >er part of the cervix are d with columnar cells, and he lower part with cubical s. In both regions the s are non-ciliated. The ids in the lower part of cervix have each a large ten, and they secrete a very acious mucus during pregicy, which in the later ges of that period plugs the external os of uterus.

In addition to these glands clear vesicles of a yellowish colour, called ovula Nabothi, may be seen in the mucous membrane between the

ae of the arbor vitae, which are supposed to result from the blockage

some of the racemose glands.

Blood-supply. —The uterus is supplied with blood by the uterine eries, and the uterine branches of the ovarian arteries.

Nerves.— The chief nerves are derived from the uterine sympaitic plexus, which is an offshoot from the pelvic plexus, and accomlies the uterine artery. It is to be noted that the pelvic plexus itains spinal fibres derived from the third and fourth sacral nerves metimes also the second), and from the upper two or three lumbar 'ves, as in the case of the bladder and rectum. The uterus also

Fig. 572. — Scheme of the Lymphatic Drainage of the Uterus (after Cuneo et Marcille).

986

A MANUAL OF ANATOMY

receives sympathetic fibres from the ovarian plexus, which is deri from the renal and aortic plexuses.

Lymphatics—Cervix Uteri. —The lymphatic vessels of the ce: have a threefold destination—namely, (i) the middle chain of external iliac glands, (2) the internal iliac glands , and (3) the inner gt of the common iliac glands.

Body. —(1) Most of the lymphatics of the body of the uterus the lymphatics of the ovary, and pass to the juxta-aortic glands. (2 few lymphatics pass to the middle chain of the external iliac gla: (3) Some lymphatics accompany the ligamentum teres of the ute and terminate in the superficial inguinal glands.

The lymphatics of the cervix communicate freely with those the body and with those of the upper part of the vagina.

Structure of the Vagina.

The wall of the vagina is composed of three coats—fibrous, n cular, and mucous.

The fibrous coat is composed of dense connective tissue.

The muscular coat consists of plain muscular tissue arranged an outer longitudinal and inner circular layer, both being closely c nected. Embedded in this coat there is a network of anastomos veins, representing erectile tissue, which is well developed round lower part of the passage. The plain muscular coat is replaced at external orifice by the striated bulbo-spongiosus muscle.

The mucous membrane is covered by stratified squamous epithelii and is provided with papillae. In the upper part of the passage it c tains mucous glands. Along the middle line of the anterior and poste walls it presents a ridge, these ridges being called the columns of vagina, or columnce rugarum. Passing off from them at right anj there are, in the virgin, numerous transverse rugae, these appearar being well marked in the lower part of the passage and absent in upper part.

Blood-supply. —The vagina is supplied with blood by the vagi arteries, the vaginal branches of the uterine arteries, and branches the internal pudendal arteries.

Nerves. —These are derived from the vaginal sympathetic pie: of each side, which is an offshoot from the pelvic plexus.

Lymphatics. —The lymphatic vessels are disposed in two set superior and inferior. The superior lymphatics come from about upper two-thirds of the vagina, and they pass to (1) the middle ch of the external iliac glands, and (2) the internal iliac glands on eit side. The inferior lymphatics come from about the lower third, ; include those from the vaginal surface of the hymen; they pass the inner group of the common iliac glands. The lymphatics fi the perineal surface of the hymen pass to the superficial ingu\ glands.

The superior and inferior vaginal lymphatics communicate fr

THE ABDOMEN

987

one another; the superior lymphatics communicate with those Le cervix uteri, and the inferior set communicate with those of the a.

Development of the Uterine Tubes, Uterus, and Vagina.

he uterine tubes, uterus, and vagina are developed from the para-mesonephric i, as described on pp. 101 and 102.

he two para-mesonephric ducts have been seen to meet and fuse into a single in the transverse pelvic ridge of mesoderm, the single tube passing to the ,1 wall of the uro-genital sinus and lying in the central thickened part of the verse ridge, which is termed the genital cord. The fused tubes within ord make the mucous lining of the uterus and vagina, the thick mesoderm e cord forming the walls of these parts ; the lateral portions of the transridge become the central parts of the broad ligament on each side of the is.

he transverse ridge is continuous on each side with the mesonephric ridge, ls, in fact, to be considered as made by the continuation of each ridge into elvis, where it meets its fellow of the other side. Hence the para-mesonephric 5, which are in the free edges of the mesonephric ridges, are also in the free 5 of the transverse ridge on each side of the central thickened ‘ cord ’; when equalities of growth-rate the ducts become altogether intrapelvic in position, necessarily lie in the free edge of the broad ligament on each side as the Qe tubes. Their fimbria begin to be apparent in the second month, are

r marked in the third month, and grow slowly after this. Accessory abnal ostia are sometimes found in the embryo, and are well known to occur

e adult. The dilatations of the tubes appear during the later foetal months, ter birth. The narrowed uterine ends are due to the inclusion of these ends le mesodermal thickening that forms the muscular uterine wall. This gening begins in the third month, and not only takes in the ends of the tubes, includes also the attachment to these of the inguinal folds, thus leading to livision of each of these into ligamentum teres and ligament of ovary. In the

h month the vaginal lumen is blocked by solid epithelial masses; these break

1 centrally in the sixth month, and the lumen is re-established.

'he remnants of the mesonephric duct and its associated tubules, being among structures included within the mesonephric ridge, find their way into the d ligament with the para-mesonephric ducts as growth proceeds. The mephric duct becomes the duct of the epoophoron, and the tubules form the igial remnants known as the paroophoron and epoophoron; it is probable the ‘ appendix vesiculosa ’ also belongs to this series, but some maintain that a persisting remnant of the pronephric system.

"he abnormal condition of the uterus known as uterus bicornis is brought it by the fact that the two para-mesonephric ducts have united at a more erior (caudal) level than they usually do. The condition known as uterus ornis is due to imperfect development of one or other para-mesonephric duct, xtremely rare cases the para-mesonephric ducts fail to unite, and by opening pendently into the uro-genital sinus they give rise to a double uterus and 'uble vagina.

Structure of the Urethra.

The wall of the urethra is composed of three coats—muscular, 'tile, and mucous. The muscular coat, which is continuous with t of the bladder, is composed of plain muscular tissue arranged as outer circular and an inner longitudinal layer. The circular fibres well developed, especially at the upper end, where they partake tewhat of the nature of a sphincter muscle. Superficial to the

988

A MANUAL OF ANATOMY

circular fibres the urethra, as it lies between the two layers of 1 perineal membrane, is embraced by the striated fibres of the sphinc urethras. The erectile coat is composed of a rich plexus of veins, si ported and pervaded by areolar and elastic tissues. This plexus continuous above with that around the neck of the bladder. 1 mucous coat is covered by transitional epithelium in its upper pa and stratified squamous epithelium in its lower part. It is provic with papillae, and is thrown into longitudinal folds, which are tempore above, but permanent below. One fold, situated on the posterior w; is larger than the others, and is known as the crest. The mucous me brane is furnished with tubular mucous glands, and between t permanent folds in the lower part there are crypts or lacunae.

Lymphatics. —The lymphatic vessels of the female urethra join th< of the bladder, which pass to the external iliac , internal iliac , and comn, iliac glands.

Development of the Urethra.— The female urethra is developed from ventral or uro-genital compartment of the cloaca, caudal to that part wh gives rise to the bladder. It represents the prostatic portion of the male uret] as low as the prostatic utricle.

The Articulations of the Pelvis.

Lumbo-sacral Articulation. —The union between the fifth lmnt vertebra and the base of the sacrum is effected by means of the folio ing ligaments: an intervertebral disc, prolongations of the anter and posterior longitudinal ligaments of the bodies of the verteb above, capsular ligaments and synovial membranes for the articu processes, ligamenta flava for the laminae, and interspinous and sup: spinous ligaments for the spinous processes. These are similar to i corresponding ligaments above the level of the fifth lumbar verteb The articulation between the bodies of the fifth lumbar and the fb sacral vertebrae belongs to the class of secondary cartilaginous join and the joints between the articular processes belong to the class synovial joints, and the subdivision plane joints. In addition to t foregoing ligaments there are two special ligaments, called luml sacral and ilio-lumbar. The lumbo-sacral ligament at either si extends from the lower aspect of the transverse process of the fii lumbar vertebra anteriorly to the upper surface of the ala of the sacn at its anterior and outer part close to the sacro-iliac articulation. II somewhat fan-shaped, and corresponds to the intertransverse ligamei of the lumbar vertebrae and the superior costo-transverse ligaments the thoracic region. The ilio-lumbar ligament extends from the of the transverse process of the fifth lumbar vertebra to the inner of the iliac crest, where it is attached for about 2 inches above i back part of the iliac fossa. It is triangular, and its direction is oi wards and slightly backwards. It is closely associated with the lov part of the anterior layer of the lumbar fascia.

Arterial Supply. —Ilio-lumbar and superior lateral sacral arteriei

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J erve-supply .—Fourth and fifth lumbar nerves, and sympathetic ients.

Movements. —Flexion, extension, and lateral movements between opposed bodies, and gliding and rotation between the articular esses.

acro-coccygeal Articulation.—This belongs to the class of secondary laginous joints. The bony elements are the fifth sacral and first ygeal vertebrae. The opposed surfaces are transversely oval, and separated by an intervertebral disc, unless in advanced life, when flosis takes place, this occurrence being earlier and more frequent le male than in the female. The ligaments are as follows: anterior superficial posterior sacro-coccygeal, which are continuations of

r. 573.— View of Pelvic Skeletal Structures from Above and in Front.

anterior and posterior longitudinal ligaments of the bodies of the tebrae; intercornual, which pass between the sacral and coccygeal nua; and lateral sacro-coccygeal, which pass between the inferior iral angles of the sacrum and the transverse processes of the first cygeal vertebra. The latter ligament is liable to become ossified. Arterial Supply .—Inferior lateral and median sacral arteries.

A 1 erve-supply .—Lower two sacral and coccygeal nerves.

Movements .—Forward and backward movements are allowed. Intercoccygeal Articulations.—These only exist prior to middle

. The union between the coccygeal segments is effected by inter'tebral discs, and anterior and posterior ligaments. The adjacent

res of the sacro-tuberous and sacro-spinous ligaments serve as lateral unents.

990

A MANUAL OF ANATOMY

Sacro-iliac Articulation. — This belongs to the class of syno joints. The bony elements are the auricular surfaces of the sacrum ; ilium. The cartilages of the auricular surface are about x \ inch th and exist as two plates, one for each surface, a small but definite syno cavity existing between the two plates. The ligaments at the j( are anterior, and long and short posterior. The anterior sacro-i ligament is composed of short fibres which are placed in front of joint. The short posterior sacro-iliac ligament, which is very strc extends from the ligamentous surface of the ilium to the ligament surface of the sacrum and the tubercles on the dorsum of the bone,

Fig. 574. —Ligaments of the Right Half of the Pelvis

(Posterior View).

direction of the fibres being downwards and inwards. The 1 ( posterior sacro-iliac ligament lies superficial to the posterior, s extends from the posterior superior iliac spine and the adjacent p of the iliac crest to the third and fourth series of tubercles on the dors of the sacrum. It is really a detached part of the short posterior sac iliac ligament. The great and small sacro-sciatic ligaments are acc sory to this joint.

The sacro-tuberous ligament (great sacro-sciatic ligament) is

tached by one extremity to the posterior inferior iliac spine, and sides of the last three sacral and first coccygeal vertebrae, and by

i

THE ABDOMEN

99i

extremity to the inner border of the ischial tuberosity. From atter point it sends forwards an expansion, called the falciform ss, which is attached to a sharp ridge on the lower part of the inner

e of the ramus of the ischium close to its medial border. The

ent is broad at its attached ends, especially the upper, but in

n g towards the ischial tuberosity it becomes narrow. Its direction

inwards and forwards, aild its ischial fibres are continuous with endinous origin of the long head of the biceps femoris. By its Trial surface it gives origin to part of the gluteus maximus, and lg on this surface are the plexiform loops formed by the lateral dies of the posterior primary divisions of the first three sacral

s. Its deep surface gives origin to some fibres of the pyriformis,

lower down is intimately connected with the sacro-spinous ligaThe falciform process affords attachment to the lower part of jarietal pelvic fascia. The sacro-tuberous ligament is pierced by

occygeal branch of the inferior gluteal artery, the sacral branch

e internal pudendal artery, and the perforating cutaneous nerve the sacral plexus. The ligament assists in the formation of the

er and lesser sciatic foramina.

ie sacro-tuberous ligament is to be regarded as a detached portion of the lead of the biceps femoris muscle.

he sacro-spinous ligament (small sacro-sciatic ligament), which is gular, is attached by its base to the sides of the last two sacral first coccygeal vertebrae, where it is intimately connected with the i superficially placed sacro-tuberous ligament. Its apex is attached Le tip of the spine of the ischium. Its deep surface is incorporated the coccygeus muscle, and along with the spine of the ischium it s the separation between the greater and lesser sciatic foramina.

he sacro-spinous ligament is to be regarded as resulting from the fibrous leration of the superficial part of the coccygeus muscle.

I rterial Supply of the S acro-iliac Articulation. —Ilio-lumbar, superior al sacral, and superior gluteal arteries.

lerve-supply .—Superior gluteal and anterior primary divisions, lateral branches of the posterior primary divisions of the first- two il nerves.

Movements .—Stability being required at this joint, it is almost ovable. The two hip bones by their union at the pubic articulation 1 an arch, the convexity of which is directed downwards and forts. The piers of this arch are separated by a wide interval into

h the sacrum fits. The sacrum being narrower behind than in

t, the superincumbent weight of the trunk has a tendency to dise it downwards into the pelvic cavity, but this is resisted partly the powerful posterior sacro-iliac ligaments, which suspend the 3 , and partly by the strong hold which the sacrum has upon the a, in virtue of the irregularities of the opposed surfaces. Under influence of the superincumbent weight there is a tendency on the

992

A MANUAL OF ANATOMY

Anterior Pubic Ligament

Inferior Pubic Ligament

Fig. 575. —The Ligaments of the

Symphysis Pubis (Anterior Aspect)

part of the sacrum to rotate round an axis passing transversely thro the sacro-iliac joints. This tendency, however, is checked by sacro-spinous and sacro-tuberous ligaments. The ilio-lumbar 1 Superior Pubic Ligament ments prevent displacement of

fifth lumbar vertebra over base of the sacrum.

The Pubic Symphysis.—1 belongs to the class of seconc cartilaginous joints. The artici surfaces are the symphysial pects of the pubic bones, ligaments are anterior, postei superior, inferior, and interpi disc. The anterior pubic ligair is strong, and is composed superficial and deep fibres, superficial fibres are arranged an obliquely decussating man] and are chiefly constructed by aponeurotic fibres of the extei oblique and inner heads of recti abdominis muscles. The deep fibres are disposed transvers The posterior and superior pubic ligaments are weak, and consis scattered fibres. The inferior ligament (arcuate ligament) is a strc thick band of fibres, which lies at the antero-superior part of pubic arch, where it fills up and rounds off the subpubic angle. I attached superiorly to the lower part of the interpubic disc, and laterally to the adjacent parts of the inner lips of the inferior pubic rami. It is about | inch in depth, and is slightly arched, from which latter circumstance it is known as the arcuate ligament. The interpubic disc lies between the plates of cartilage which cover the bony articular surfaces. It is composed of fibro-cartilage, is thicker in front than behind, and usually contains a fissure at its upper and back part, which may extend for one-half, or even the whole length, of the disc as an oblique cleft parallel to the plane of the bony surfaces. This fissure is brought

Fig. 576. —-Vertical Section the Pubic Symphysis.

about by absorption of the tissues in that situation, and it does appear until about the tenth year of life. It is larger in the fer than in the male.

Ihe depth of the symphysis pubis is less in the female than in male.

THE ABDOMEN

993

rterial Supply .—Pubic branches of the inferior epigastric and rator, and superficial external pudendal arteries.

J erve-supply .—Probably the hypogastric branch of the ilio-hypo•ic, ilio-inguinal, and pudendal nerves.

iovements .—Very slight separation is allowed at this joint, due to ing of the connecting structures. This is most apparent during nancy and parturition.

heater Sciatic Foramen. —This foramen is formed by the greater ic notch, the spine of the ischium, the sacro-tuberous ligament, the sacro-spinous ligament. For its compartments and the struc3 which pass through them, see p. 534.

,esser Sciatic Foramen. —This foramen is formed by the lesser

ic notch, the spine of the ischium, the sacro-tuberous ligament, and

sacro-spinous ligament. For the structures which pass through it, iluteal Region.

Obturator Membrane and Obturator Canal.

die obturator membrane is attached to the posterior margin of the imference of the obturator foramen, except superiorly opposite the Lrator groove; this last it converts into a hbro-osseous canal for passage of the obturator vessels and nerve. In this situation it is sd posteriorly by the parietal pelvic fascia. Its fibres are arranged n irregular, decussating manner. Its posterior or pelvic surface is dy covered by the obturator internus muscle. The anterior or oral surface is in like manner covered by the obturator externus cle, and at its circumference there is an arterial loop formed by the

erior and anterior terminal branches of the obturator artery,

rhe obturator canal is a hbro-osseous canal, which is situated above upper border of the obturator membrane. Its upper boundary,

h represents the osseous element, is formed by the obturator groove

he inferior surface of the superior pubic ramus, the direction of the

we being downwards, forwards, and inwards. The lower boundaiy, ch represents the fibrous element, is formed by the junction of the ietal pelvic fascia with the upper border of the obturator membrane r the upper border of the obturator internus. d he canal transmits obturator vessels and obturator nerve, the nerve being above the jry.

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