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

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A MANUAL OF ANATOMY

front wall. Its opening looks to the right; it is attached here, and continu< with the meso-duodenum and general mesentery. Otherwise it lies free betw< the mesentery and left lobe of liver. When the umbilical sac discharges ■ intestinal coils, they displace the lesser sac and stomach to the left and upwa and push the colon and median meso-colon to the left and backwards, so tl these lie behind the coils and are overhung by the lower part of the lesser s projecting below the stomach (see Figs. 511 and 512). This projection of 1 lesser sac, at first unattached to the colon, on which it lies, is the early grea omentum. The lesser sac fuses with the peritoneum of the back wall, as a does the meso-colon, so far as its originally median part is concerned; thus 1 lesser sac is fixed above, while below this is the primitive transverse meso-coli On referring to Fig. 463, it will be seen that in this region there are four layers peritoneum at this stage. The upper two layers are continuous with the two p

Fig. 462. —The Retro-c,ecal Recess (after Jonnesco).

terior or ascending layers of the greater omentum, and represent the origir meso-gastrium. The lower two layers belong to the primitive transverse met colon. Subsequently the lower of the upper two layers and the upper of t] lower two layers unite and disappear. There are thus left only two layers of pei toneum, which constitute the transverse meso-colon of the adult, the lower lay of which is part of the primitive transverse meso-colon, whilst the upper layer part of the greater omentum. In fact, both layers are ultimately derived frc the two posterior or ascending layers of the greater omentum. As the resi of these changes, the pancreas comes eventually to lie behind the peritoneu whereas it was originally contained between the two layers of the meso-gastriu The inferior mesenteric vessels reach the intra-abdominal colon by runni between the layers of the median mesentery (meso-colon); when this is fore against the left dorsal wall by the pressure of the coils of gut, and adheres the the vessels are left behind the peritoneum.

THE ABDOMEN

795

The ascending and descending meso-colon, as a rule, disappear as a result of Ihesion.

The pelvic meso-colon persists and the meso-rectum disappears.

Structure of the Peritoneum. —The peritoneum is a typical serous membrane

e the pleura, the serous portion of the pericardium, and the tunica vaginalis,

•iefly stated, it consists of a homogeneous connective-tissue basement memane, containing elastic tissue, and lined with endothelium.

s. 463.— Scheme, based on Embryonic Conditions, to show Fcetal Arrangements of Peritoneum and Composition of Transverse Mesocolon.

The wall of the lesser sac is really composed of two layers, but these

layers are not shown in the figure.

Development. —'The parietal peritoneum is developed from the somatic meso'Ul of the somatopleure of the body-wall. The visceral peritoneum is developed

m the splanchnic mesoderm of the splanchnopleure of the primitive intestinal

)e.

Blood-supply of the Intestinal Canal. —The intestinal canal receives blood-supply from the superior and inferior mesenteric arteries, th the exception of the upper portion of the duodenum and a portion the rectum.

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A MANUAL OF ANATOMY

Superior Mesenteric Artery. —This vessel springs from the front c the abdominal aorta about \ inch below the coeliac artery. It is a first directed downwards behind the body of the pancreas and th splenic vein. It then passes downwards and forwards in front of th uncinate process of the pancreas and third part of the duodenum, a the lower border of which latter it takes up its position between th two layers of the mesentery proper. The vessel then passes down wards near the root of the mesentery, its course being slightly curve*

Sup. Mesenteric Vein Sup. Mesenteric Art.

Fig. 464.—The Superior Mesenteric Artery and its Branches

(after Spalteholz).

with the convexity towards the left side, and it terminates near the ileo-colic junction in the last ileal artery, which anastomoses with the ileal branch of the ileo-colic artery. The vessel is surrounded by a tough sheath formed by the superior mesenteric sympathetic plexus.

Branches — Left Branches .—These are called the jejunal and ileal arteries (rami intestini tenuis), and are at least twelve in number. They pass downwards and to the left between the two layers of the mesentery proper, and supply the jejunum and ileum. After a course of about 2 inches each divides into two branches, which by their junction with

THE ABDOMEN

797

)ntiguous branches give rise to primary arcades. From the conexities of these arcades small branches .are given off, which act in a milar manner, and give rise to secondary arcades. This disposition of rteries goes on so as to form tertiary, quaternary, and even quinary rcades. The minute vessels arising from the arcades of the last er enter the wall of the jejunum and ileum along the mesenteric order, where each divides into two branches, which encircle the owel beneath its serous covering, thus providing for an equal arterial apply to all parts of the wall. From the rings thus formed branches enetrate deeply to reach the mucous coat. Each jejunal and ileal rtery, as well as its various branches, conducts to the bowel an offshoot f the superior mesenteric sympathetic plexus.

The branches from the terminal arcades divide some distance away

om the intestine, and diverging leave an interval into which the

itestine can expand without throwing undue strain on the vessels, 'his arrangement obtains generally all along the abdominal portion f the alimentary canal.

Right Branches — Ileo-colic Artery. —This vessel is the lowest of tie right branches, and in many cases it arises in common with the ight colic. Its course is downwards and outwards towards the right iac fossa behind the peritoneum, and it divides into two branches, scending and descending. The ascending branch (colic branch) passes pwards and forms an arcade with the descending branch of the right olic, from which branches proceed to the lower part of the ascending olon. The descending branch (ileo-ccecal branch) passes to the upper •art of the ileo-colic junction, where it furnishes the following branches: leal, to the terminal part of the ileum, where it anastomoses with the ist ileal artery; appendicular , which, descending behind the terminal >art of the ileum, passes between the two layers of the meso-appendix, nd so reaches the vermiform appendix; anterior ccEcal , to the front of he caecum; and posterior ccecal, to its posterior aspect.

Right Colic Artery. —This is the second branch in order from below ipwards, and in many cases it arises in common with the ileo-colic. ts course is transversely to the right behind the peritoneum, and it livides into two branches, descending and ascending. The descendng branch anastomoses with the ascending branch of the ileo-colic, and he ascending branch with the right branch of the middle colic. The ircades thus formed furnish branches to the ascending colon, which n their course form secondary and tertiary arcades.

Middle Colic Artery. —This vessel arises from the right side and ront of the main trunk about 2 inches above the right colic on a level vith the lower border of the third part of the duodenum. Its course s forwards between the two layers of the transverse meso-colon, and it livides into a short right and a long left branch. The right branch mastomoses with the ascending branch of the right colic, and the eft branch with the ascending branch of the upper left colic from the nferior mesenteric. The arcades thus formed furnish branches to the niddle colon, which in their course form secondary and tertiary arcades.

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A MANUAL OF ANATOMY

Inferior Pancreatico-duodenal Artery.— This small vessel usual; arises from the right side of the main trunk opposite the upper bord< of the third part of the duodenum, but it may spring from the fir; jejunal artery. Its course is to the right behind the superior mesenter vein, and between the head of the pancreas and the third part of tl duodenum. It terminates by dividing into two branches, anteri< and posterior, which ascend one in front of the other behind the hea of the pancreas supplying it and the adjacent portions of the duodenur and anastomosing with the anterior and posterior branches respective; of the superior pancreatico-duodenal of the gastro-duodenal from tl

SP

Fig. 465. —Schematic Drawing to show Upper Branches of Superic

Mesenteric Artery.

Non-peritoneal area stippled; A, TT, ascending and transverse meso-colon M, middle colic; R, right colic; IC, ileo-colic; I VC, inferior vena cava.

hepatic. The vessel is accompanied by an offshoot from the superi( mesenteric sympathetic plexus, and when it arises from the first jejun; artery it passes behind the superior mesenteric artery.

Superior Mesenteric Vein.— This vein is formed by tributaries whic return the blood from the parts of the intestinal canal supplied by tl superior mesenteric artery, and it receives in addition the right gastr* epiploic vein. It ascends on the right -side of the superior mesenter artery. After leaving the mesentery it passes over the third part «  the duodenum and uncinate process of the pancreas, and finally, behir the neck of the latter organ, joins the splenic vein to form the port

THE ABDOMEN

799

n. The vessel and its tributaries are destitute of valves, so that the od can regurgitate in cases of portal obstruction.

Superior Mesenteric Sympathetic Plexus. —This plexus is derived n the solar plexus. It closely surrounds the superior mesenteric sry in the form of a tough sheath, and furnishes offshoots which ompany all the branches of that vessel.

Lymphatic Vessels of Small Intestine. —These, which are called

eals, originate in the villi of the mucous membrane of the small

sstine (see p. 866). They leave the wall of the bowel at the mesenlc border, those of the jejunum exceeding in number those of the im. Within the mesentery they take a course inwards and up:ds, becoming in succession the afferent and efferent vessels of the ups of mesenteric glands. At the root of the superior mesenteric 5 ry the lacteals, which have now emerged from the innermost

Fig. 466. —Portion of Jejunum with its Mesentery, showing Lacteal Vessels and Mesenteric Glands.

senteric glands, terminate in from one to four lymphatic trunks, ich open into the cisterna chyli.

Superior Mesenteric Glands. —These are about 150 in number, and situated within the mesentery proper and along the course of the nk of the superior mesenteric artery. In health their average size ibout that of a small pea, except along the course of the main artery, ere they are somewhat larger; they are more numerous in the jejunal m in the ileal mesentery. They receive the lacteals from the lower "t of the duodenum, the jejunum, and the ileum, and also the lymatics from the ascending and transverse colon. The glands may divided into three groups: a group of large and important glands the root of the mesentery, particularly numerous along the upper d of the superior mesenteric vessels; a second group in the neighboured of the first arterial arcades; and a third group of small glands in 5 neighbourhood of the terminal arcades; certain of this last group L V lie, especially in the upper jejunal region, in close proximity to i intestine or even upon it.

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A MANUAL OF ANATOMY

In the ileo-colic angle there is a special group of glands, called ileo-colic glands. These receive afferent vessels from' the termi part of the ileum, the caecum, the vermiform appendix, and beginn of the ascending colon; their efferent vessels pass to the innerm group of superior mesenteric glands. The efferent vessels of superior mesenteric glands usually unite with those of the coe glands to form one or more intestinal trunks, which, joining the effer

Rt. Gastroepiploic Art. Liver

Fig. 467. —The Inferior Mesenteric Artery and its Branches

(after Spalteholz).

lymphatics from the pre-aortic and retro-aortic glands, form 1 cisterna chyli.

Lymphatic Vessels of Ascending and Transverse Colon. —The ly

phatics of the ascending colon terminate in two ways as follow those from the lower part pass to the innermost group of super mesenteric glands, whilst those from the upper part go to the me: colic glands. The lymphatics of the transverse colon become affen vessels of the meso-colic glands, the efferent vessels of which j<

THE ABDOMEN

801

e terminal intestinal lymphatic trunks from the superior mesenteric mds. The lymphatic vessels from the transverse colon freely comLinicate with those in the greater omentum.

Inferior Mesenteric Artery. —This vessel arises from the front of e abdominal aorta towards its left side about ij inches above the Eurcation. Its course is downwards and to the left towards the t iliac fossa. It is behind the peritoneum, and lies first upon the rta, and then on its left side, where it is supported by the psoas ijor. Subsequently it is continued as the superior rectal artery er the left common iliac vessels. The artery is surrounded by the Eerior mesenteric sympathetic plexus.

Branches—Upper Left Colic Artery. —This vessel passes transversely the left, behind the peritoneum and over the lower part of the left Iney, and divides into two anches, ascending and deeding. The ascending inch anastomoses with the t branch of the middle lie, and the descending mch with the ascending anch of the lower left colic tery. The arcades thus rmed supply branches to e left extremity of the msverse colon and the

scending colon, which in

eir course form secondary Ld tertiary arcades.

Lower Left Colic Arteries igmoid Arteries) . — These e usually three in number -superior, middle, and inrior—but they are very triable and may arise as single trunk. They pass )wnwards and to the left 7 er the psoas major, ureter, and testicular vessels, and supply te lower part of the descending colon and the pelvic colon. The [perior lower left colic artery , which lies, as a rule, behind the perineum, divides into two branches, ascending and descending. The sending branch forms an arcade with the descending branch of the pper left colic, and the descending branch passes between the two yers of the pelvic meso-colon, where it anastomoses with the middle wer left colic artery; this artery, or one of its branches, may lie in the iterior wall of the intersigmoid recess. The middle and inferior wer loft colic arteries pass between the two layers of the pelvic meso)lon, where they form arcades with the descending branch of the iperior lower left colic, with one another, and with the superior rectal

5i

Fig. 467A. —Schematic Drawing to show the Lymphatic Arrangements for Ascending and Greater Part of Transverse Colon.

The glands are grouped along branches of the superior mesenteric artery.

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A MANUAL OF ANATOMY

a

artery. The branches of these arcades form secondary, or ev< tertiary, arcades before the terminal branches are given off.

The superior rectal artery (superior hsemorrhoidal artery) is tl

continuation of the inferior mesenteric, and will be found describ( on p. 961.

Inferior Mesenteric Vein.—This vein is formed by tributaries whi( return the blood from the parts of the large intestine supplied 1 the inferior mesenteric artery. It lies at first near the left side of i artery, but soon leaves it and ascends on the left psoas major, whe it lies on the left side of the aorta behind the peritoneum. In th course it crosses the left testicular artery and left renal vein. It pass<

to the left of the duodeno-jejun flexure lying in the anterior wall 1 the paraduodenal recess, and the curving sharply to the right, passi behind the pancreas to join the splen vein near its termination in the port vein. It may, however, open ini the angle of junction of the splen and superior mesenteric veins, or ini the superior mesenteric vein near i termination. The inferior mesenter vein and its tributaries are destitui of valves, so that the blood can n gurgitate in cases of portal obstru< tion.

Inferior Mesenteric Sympathet: Plexus.—This plexus is derived froi the left half of the aortic plexus. ] forms a tough sheath round tt artery, and furnishes offshoots wit its branches.

Inferior Mesenteric Glands.—Thes glands are situated around the roc and along the trunk and branches c the inferior mesenteric artery. Thos around the root of the vessel cor

Fig. 467B. — Scheme to illustrate the Lymphatic Drainage of Descending Colon and Iliac Loop, and Terminal Portion of Transverse Colon.

stitute the inferior mesenteric group of the pre-aortic glands.

The afferent vessels are derived from (1) the lower part of the descent ing colon , (2) the iliac part of descending colon, (3) the pelvic color and (4) some of the lymphatics of the rectum.

Their efferent vessels pass to the inferior mesenteric group of pre aortic glands.

Lymphatic Vessels of Descending and Pelvic Colon.—The lymphatic of the descending colon are singularly scanty; they terminate in two way as follows: those of the upper part pass to the meso-colic glands, whils those of the lower part with the lymphatics of the pelvic colon pas to the inferior mesenteric group of pre-aortic glands.

THE ABDOMEN

803

Lymphatic Glands of Large Intestine (Colic Glands).—The glands i arranged in groups, named according to the portion of intestine which they are related, and they are situated behind the respective rts, except those belonging to the transverse colon, which lie between 3 two layers of the transverse meso-colon, and are known as the iso-colic glands.

Position and Connections of the Duodenum.—The duodenum is 3 first part of the small intestine. It measures from 10 to 11 inches length and is the widest and least movable part. It extends from

Kidneys (RK, LK).

SP, testicular vessels; U, ureter; A, aorta; I VC, inferior vena cava.

s pylorus to the left side of the body of the second lumbar vertebra, lere it ends in the jejunum. It describes a somewhat U-shaped rve with the concavity directed upwards and to the left in close aptation to the head of the pancreas. It is devoid of a mesentery, d is divided into three parts—first, second, and third.

First or Superior Part.—The first part extends from the pylorus the right side of the neck of the gall-bladder. It lies in the epistnc region, and is about 2 inches in length, its direction being wards, backwards, and to the right when the stomach is empty, but ectly backwards when that organ is distended. The lesser omentum

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A MANUAL OF ANATOMY

furnishes a complete covering to about the first inch; the remainder i covered by peritoneum only in front. The first part is therefore com paratively movable.

Relations— Superior. —The caudate process of the liver and th hepatic artery. Anterior.— The quadrate lobe of the liver and the gal] bladder. Posterior. —The portal vein, gastro-duodenal artery, bile duct, and neck of the pancreas. Inferior. —The head of the pancrea and the division of the gastro-duodenal artery into its terminal branches The first part lies below the opening into lesser sac.

Second or Descending Part.—This part extends from the right sid of the neck of the gall-bladder to the right side of the body of the thin (sometimes fourth) lumbar vertebra. It lies at first in the epigastric and subsequently in the umbilical region; its length is from 3 to 4 inches and its direction is almost vertically downwards behind the right ex tremity of the transverse colon. The anterior surface is covered b; peritoneum, except opposite the transverse colon. If there is n< transverse meso-colon at this point, there is a distinct area left un covered and connected to the colon by areolar tissue. If, however there is a transverse meso-colon present at this point, the bare area i trifling. The posterior surface is destitute of peritoneum. The secom part is therefore very immovable.

Relations— Anterior. —From above downwards the liver and th gall-bladder near its neck, the right extremity of the transverse colon and some coils of the small intestine. Posterior. —The anterior surfac of the right kidney near the hilum, the inferior vena cava, and th psoas muscle. Right. —The right flexure of the colon, and the righ lobe of the liver. Left. —The head of the pancreas, which may encroacl upon it both anteriorly and posteriorly, the bile-duct, and the anterio and posterior branches of the superior and inferior pancreatico-duodena arteries. The bile-duct and pancreatic duct enter the wall of this par at the junction of the inner and posterior aspects a little below th centre.

Third or Inferior Part.—This part extends from the right side 0 the body of the third (sometimes fourth) lumbar vertebra to the lef side of the body of the second on a level with its upper border. A this point it makes a sharp bend forwards, and terminates in th jejunum, thus forming the duodeno-jejunal flexure. It lies at first h the umbilical, and subsequently in the epigastric region; its lengt is about 5 inches, and its direction is at first obliquely to the left an< upwards, and afterwards vertically upwards. Its anterior surface i covered by peritoneum derived from the descending layer of the trans verse meso-colon, except where it has the superior mesenteric vessel in front of it. There is no peritoneum behind it, and consequently i is fixed in position.

Relations— Anterior. —The superior mesenteric vessels and the uppe' part of the root of the mesentery, with portions of the small intestinf on either side of these. Posterior .—The inferior vena cava, aortj (below the origin of the superior mesenteric artery), left renal vein

THE ABDOMEN

805

ft psoas major, and left crus of the diaphragm. Superior .—The

>wer part of the head of the pancreas (including its uncinate process), nd the inferior pancreatico-duodenal vessels.

The terminal portion of the third part is sometimes spoken of as he fourth or ascending part of Treves. It is covered by peritoneum n the left side, as well as in front, and in cases where a retro-duodenal scess is present it is partially covered by peritoneum behind towards re left side. The duodenal recesses of the peritoneum are met with n the left side of this portion. The duodeno-jejunal flexure is sus

Hepatic Artery Left Gastric Artery

Fig. 469.—The Arteries of the Stomach, Duodenum, Pancreas,

and Spleen.

ended from the right crus of the diaphragm by a fibro-muscular undle, called the suspensory muscle of duodenum. The muscle consists f both striped and unstriped muscular fibres, as well as of elastic ^ssue; as it passes downwards it lies in a fold of peritoneum called the uodeno-jejunal fold immediately to the right of the coeliac artery. Its bres are inserted mainly into the posterior surface of the duodeno"junal flexure, but certain of them are continued into the mesentery.

Blood and Nerve Supply of the Duodenum.—The arteries of the uodenum are as follows: (1) the right gastric branch of the hepatic; 2) the superior pancreatico-duodenal branch of the gastro-duodenal

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A MANUAL OF ANATOMY

of the hepatic; and (3} the inferior pancreatico-duodenal branch of t superior mesenteric, ?&»&*&**£** »

The veins terminate in the superior mesenteric, splenic, and pori veins.

The nerves are derived from the hepatic and superior mesentei sympathetic plexuses.

The lymphatic vessels of the first part of the duodenum pass to t retro-pyloric glands, and those of the second and third parts pass the prepancreatico-duodenal and retro-pancreatico-duodenal glanc which lie along the anastomotic chains formed by the anterior ai posterior branches of the pancreatico-duodenal arteries.

Position and Connections of the Pancreas.—The pancreas is a loi narrow gland which is situated behind the stomach on a level with i first and second lumbar vertebrae. Its right extremity occupies i. duodenal curve, and its somewhat pointed left extremity is in conta with the spleen. The greater part of the organ lies in the epigasti region, but its left extremity is situated in the left hypochondriur The .anterior surface is covered by the ascending layer of the transver me9L-colon, and the inferior surface by the descending layer, but tl posterior surface is destitute of serous covering. The length of tl organ is from 6 to 8 inches, its depth from 1 to ij inches, except at tl right and left extremities, and its thickness from 1 to £ inch. I weight is about 3J ounces. It has been likened in shape to the capit letter J laid thus c- (Birmingham). For convenience of descriptic it is divided into a head, neck, body, and tail.

The head is the enlarged flattened right extremity. It chief corresponds with, and is closely attached to, the second and thii parts of the duodenum as far almost as the duodeno-jejunal flexur The expansion of the head to the left along the upper part of the thii portion of the duodenum is called the uncinate process.

Relations— Anterior. —The transverse colon with its meso-coloi and the superior mesenteric vessels crossing the uncinate proces The formation of the portal vein may occur in front of the upturne extremity of the uncinate process. Posterior— The inferior-vena cav right renal vessels, right crus of the diaphragm, aorta, and left ren; vein. Superior. —The first part of the duodenum and the superic pancreatico-duodenal artery. Inferior. —The third part of the du< denum, and the inferior pancreatico-duodenal artery. Right. —Tl second part of the duodenum, with the bile-duct behind, as low e a little below the centre, and the anastomoses between the superi( and inferior pancreatico-duodenal arteries. '

The neck may be defined as the part in front of the origin of the ver portae and the termination of the superior mesenteric vein. It. spring from the anterior surface of the head near its upper part; and. i*s aboij 1 inch in length. Its direction is upwards and to the left, and forms the connecting link between the head and body. The gastr* duodenal and superior pancreatico-duodenal arteries occupy groov| on its right side; the commencement of the first part of the duodenu,

THE ABDOMEN 807

in front of it, whilst the origin of the portal vein and the termination

f the superior mesenteric vein are behind it.

The body passes to the left with a slight inclination backwards fter it has crossed the aorta. It is triangular, and presents three arfaces (anterior, posterior, and inferior) and three borders (superior, nterior, and posterior).

The anterior surface, which is covered by peritoneum, is in relation ith the posterior surface of the stomach. At its right extremity, 1st below the coeliac artery, it presents a prominence, called the fiber omentale from its relation to the lesser omentum. The tuber mentale of the pancreas, it will be noticed, lies behind the lesser mentum, whereas that of the liver lies in front of it. The posterior urface, which is destitute of peritoneum, is related to the following tructures: the aorta below the coeliac artery, with a portion of the oeliac plexus; the origin of the superior mesenteric artery; the left iprarenal gland; and the left kidney with its vessels. The.splenic ein passes from left to right in contact with this surface near the iperior border. The inferior surface, which is covered by peritoneum,

moulded on the duodeno-jejunal flexure, some coils of the jejunum,

nd the left extremity of the transverse colon. The coeliac artery promts forwards over the superior border above the tuber omentale. To he left of this artery the splenic artery pursues its tortuous course to he spleen, and to the right of it the hepatic artery lies for a short istance. The transverse meso-colon is attached to the anterior border, long which its separation into ascending and descending layers takes lace, the former covering the anterior surface of the organ, and the itter, on its way backwards, investing the inferior surface. The osterior border presents nothing noteworthy.

T 1 j tail corresponds with the left extremity where the pancreas is arrowest, and is in contact with the lower end of the gastric surface f the spleen behind the hilum. The terminal part is in the lieno-renal igamentt

For the structure and development of the pancreas, see pp. 891, 894.

Coeliac (Solar) Plexus et the Sympathetic System. —The coeliac plexus 3 of large size, and is situated deeply in the epigastric region, behind he stomach and in front of the crura of the diaphragm and the aorta lose to the origins of the coeliac artery and superior mesenteric artery, t extends from one suprarenal gland to the other, and is composed f nerve-fibres and ganglia. The plexus receives its chief fibres from he greater and lesser splanchnic nerves of each side, which contain a irge number of spinal fibres. The greater splanchnic nerve is formed >y rqots derived usually from the fifth to the ninth or tenth thoracic ympathetic ganglia inclusive, and it enters the abdomen by piercing he crus of the diaphragm. The lesser splanchnic nerve arises by two oots from the ninth and tenth thoracic ganglia, and it also enters he abdomen by piercing the crus of the diaphragm. The plexus also eceives fibres from the right vagus nerve. Two of the ganglia of the 'celiac plexus are of large size, and are situated one at either lateral

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A MANUAL OF ANATOMY

Aorta (Esophagus

Greater Splanchnic Nerve

Phrenic Plexus

Diaphragm

,Left Vagus

_. Stomach (cut)

,, Right Vaj

Hepatic Plexus.

Gr. Splanchnic N.--vj Lesser Splanchnic N.AffiJ

Super

I

Suprarenal Plexus 'A

Lowest Splanchnic^ \' Nerve *

Renal Plexus

Lumbar Sympathetic.. Trunk

Testicular Plexus..]

Ureter (cut)_\

Hypogastn (Presacr

Right Pelvic Plexus.—

' — Communications bet.i

Pelvic Sympathetic Ti

Pelvic Sympathetic Cord

-.Sacral Plexus

_Ganglion Impar

Fig. 470. —The Sympathetic System in the Abdomen and Pelvis

(Hirschfeld and Leveille).

R.K., right kidney; R.T., right testis,

THE ABDOMEN

809

le. They are called the cceliac ganglia (semilunar ganglia), right and t. Each lies over the corresponding crus of the diaphragm close the suprarenal gland, that of the right side being under cover of e inferior vena cava, and each receives at its upper part the greater lanchnic nerve. The lower part of each ganglion is more or less tached, and is known as the aortico-renal ganglion, which lies over e root of the renal artery, and in which the lesser splanchnic nerve rminates. From each cceliac ganglion branches proceed in a radiating inner upwards, outwards, downwards, and inwards. The inner oup of fibres extend from one ganglion to the other, embracing the diac artery as they cross the aorta, and forming the cceliac plexus, lich receives fibres from the right vagus nerve, and contains numerous lall ganglia.

The cceliac plexus furnishes three secondary plexuses—superior stric, splenic, and hepatic. The superior gastric plexus accompanies e left gastric artery to the lesser curvature of the stomach, and supies branches to the adjacent portions of the anterior and posterior rfaces of that organ. The splenic plexus goes with the splenic artery, id receives branches from the right vagus nerve. It is distributed, th the branches of the artery, to the pancreas, cardiac extremity of e stomach, left half of its greater curvature and adjacent portions its surfaces, and the spleen. The hepatic plexus accompanies the tery of that name, and receives branches from the left vagus nerve, s distribution corresponds with that of the artery, and its offshoots e as follows: pyloric to the lesser curvature of the stomach; gastrolodenal, dividing into right gastro-epiploic to the greater curvature the stomach, and superior pancreatico-duodenal to the head of the .ncreas, and the first and second parts of the duodenum; cystic to the 11 -bladder; and hepatic to the liver.

The diaphragmatic or phrenic plexus receives its fibres from the >per part of the coeliac ganglion, and it accompanies the phrenic artery the diaphragm, giving branches in its course to the suprarenal plexus. The suprarenal plexus receives its fibres from the coeliac ganglion d coeliac plexus. It contains small ganglia, and is joined from »ove by branches from the phrenic plexus, and below by branches )m the renal plexus. It is distributed to the suprarenal gland.

The renal plexus derives its fibres from the aortico-renal ganglion, e coeliac and aortic plexuses, and the lowest splanchnic nerve when esent. (The lowest splanchnic nerve arises from the eleventh oracic ganglion, and enters the abdomen behind the medial arcuate

ament, or through the crus of the diaphragm.) The fibres of the

nal plexus, which contain ganglia here and there, are distributed th the renal artery to the kidney, branches being also given to the prarenal plexus, testicular plexus (ovarian in the female), and to the eter.

The superior mesenteric plexus is a continuation of the coeliac exus, and also receives fibres from the coeliac ganglia. It contains ganglion, called superior mesenteric, in contact with the origin of

8 io

A MANUAL OF ANATOMY

Fig. 471. —Scheme of the Sympathetic Nerve in the Abdomen

and Pelvis (Flower).

S.C. Sympathetic Trunk 1,2,3,4. Lumbar Ganglia a,b,c,d, Pelvic Ganglia G.I. Ganglion Impar

G. S. Greater Splanchnic S.S. Lesser Splanchnic L.S. Lowest Splanchnic D.P. Phrenic Plexus

S.R.P. Suprarenal Plexus

R. P. Renal Plexus

S. P. Testicular Plexus A.P. Aortic Plexus

I.M.P. Inferior Mesenteric Plexus L.C.P. Upper Left Colic Plexus S.P. Lower Left Colic Plexus S.H.P. Superior Rectal Plexus

H. P. Hypogastric Plexus

R.I.P. Jejunal and

P.P. Pelvic Plexus E.P. Epigastric Plexus C.P. Cceliac Plexus S.P. Splenic Plexus Pa.P. Pancreatic Plexus

L. G.P. Left Gastro-epiploic Plexus

B. S. Branches to Spleen

G. P. Superior Gastric Plexus

H. P. Hepatic Plexus Pvl.P. Pyloric Plexus

G.D.P. Gastro-duodenal Plexus

C. P. Cystic Plexus B.L. Branches to Liver

S.M.P. Superior Mesenteric Plexus I.C.P. Ileo-colic Plexus R.C.P. Right Colic Plexus

M. C.P. Middle Colic Plexus Plexuses

THE ABDOMEN

811

ie artery of that name, and it accompanies that vessel and its branches d be distributed to the intestinal canal from the middle of the duoenum to the commencement of the descending colon. Its secondary lexuses are as follows: jejunal and ileal, ileo-colic, right colic/middle Dlic, and inferior pancreatico-duodenal.

The abdominal aortic plexus derives its fibres from the coeliac ganglia nd the coeliac plexus. It extends along the aorta, beyond the origin f the superior mesenteric artery, in the form of two lateral strands hich communicate freely with one another over the vessel by many iterlacing fibres. It is reinforced laterally by branches from the imbar portion of the gangliated sympathetic trunk. The two lateral irands of the plexus ultimately cross the common iliac arteries, and nite in front of the body of the fifth lumbar vertebra to form the ypogastric plexus. The aortic plexus furnishes, on either side, ranches to the lenal and testicular (or ovarian) plexuses, and supplies le coats of the aorta. The right strand gives branches to the inferior ena cava, and the left furnishes the chief fibres of the inferior mesenteric lexus.

The testicular (spermatic) plexus derives its fibres from the renal ad aortic plexuses, and accompanies the testicular artery to the testis, i the female it is called the ovarian plexus, which goes with the artery f that name to the ovary.

The inferior mesenteric plexus is derived chiefly from the left strand f the aortic plexus, and contains a ganglion, called inferior mesenteric, hich lies below the root of the inferior mesenteric artery. The plexus companies the inferior mesenteric artery, and furnishes upper left )lic, lower left colic, and superior rectal plexuses, which supply the sscending colon, pelvic colon, and rectum.

The hypogastric plexus is formed by the fusion of the two halves of ie aortic plexus after these have crossed the common iliac arteries. It reinforced by branches from the lumbar ganglia, and is situated in ont of the body of the fifth lumbar vertebra between the common ac vessels. It is a large flat plexus, measuring about i \ inches in readth, and it ends in two divisions, which become the right and left dvic plexuses.

Coeliac Artery (Coeliac Axis).—The coeliac artery is a short thick trunk hich arises from the front of the aorta between the crura of the aphragm just below the aortic opening. Its direction is forwards id slightly downwards over the superior border of the body of the mcreas, and after a course of about 4 inch it divides into three radiatg branches—left gastric, splenic, and hepatic. Of these the splenic ^the largest, except during foetal life, when it is exceeded by the -patic. The branches of the coeliac artery supply the stomach, ■lodenum, pancreas, spleen, liver, and gall-bladder.

Relations.—The caudate lobe of the liver above, the superior border | body of the pancreas and splenic vein below, the lesser omentum ' J ron l, and a coeliac ganglion on either side. The artery is closely Grounded by the coeliac sympathetic plexus.

8 l2

A MANUAL OF ANATOMY

The left gastric artery (coronary artery) is directed upwards and

the left as far as the lesser curvature of the stomach on the right s: of the oesophagus. It then, on reaching the bare area at the back the stomach, bends sharply forwards and downwards, and passi between the two layers of the lesser omentum descends in two divisic from left to right along the lesser curvature towards the pylorus, wh it anastomoses with the two divisions of the right gastric branch of 1 hepatic. The artery is surrounded by the superior gastric sympathe plexus.

Branches. —These are oesophageal, cardiac, and gastric. The cesopi geal branches arise when the artery reaches the lesser curvature, a they ascend through the oesophageal opening of the diaphragm anastomose on the gullet with the lower oesophageal branches of t thoracic aorta. The cardiac branches are distributed to the card: end of the stomach, where they anastomose with the short gast branches of the splenic. The gastric branches arise from the t divisions of the artery on the lesser curvature, and pass to the frc and back of the stomach, where they anastomose with branches of t gastro-epiploic arteries.

The left gastric vein ascends from right to left along the les: curvature of the stomach as far as the oesophagus, where it receh a few oesophageal tributaries, after which it turns to the right a opens into the portal vein.

The splenic artery takes a tortuous course to the left along t superior border of the body of the pancreas behind the lesser s; On reaching the front of the left kidney it enters the lieno-renal li£ ment, and breaks up into several splenic branches which enter t spleen through the hilum. The artery is invested by the splenic sy pathetic plexus; the splenic vein lies below it, and behind the pancre

Branches .—These are pancreatic, left gastro-epiploic, short gastr and splenic. The pancreatic branches arise at intervals along t superior border of the pancreas, which they enter. One of the known as the arteria pancreatica magna , enters the organ towai its left end, and passes from left to right, lying a little above the pa creatic duct. The left gastro-epiploic artery arises near the spleen, a passes within the gastro-splenic ligament to the greater curvature of t stomach, along which it descends from left to right between the b layers of the greater omentum as far as the centre, where it anastomoJ with the right gastro-epiploic. It furnishes gastric branches to the fro and back of the stomach, which anastomose with branches of the 1< gastric artery, and epiploic branches, which descend into the greai omentum, these latter being long and slender. The short gash branches arise from the terminal part of the splenic and from its spier branches. They are about five in number, and having passed with the gastro-splenic ligament to the cardiac extremity of the stomac they anastomose with branches of the left gastro-epiploic and k gastric arteries. The splenic branches are about five in number, ai pass to the spleen within the lieno-renal ligament.

THE ABDOMEN

813

The splenic vein is formed by the union of about five veins which nerge from the spleen. It is of large size, and passes from left to ght behind the pancreas near its superior border, where it lies below le splenic artery. Having crossed the aorta, it joins the superior lesenteric vein to form the portal vein behind the neck of the pan•eas. The vein receives the following tributaries: the short gastric, le left gastro-epiploic, many pancreatic veins, and the inferior mesen^ric (as a rule).

Gastroduodenal Artery Portal Vein j Pyloric Artery

Fig. 472. —The Arteries of the Stomach, Liver, and Spleen

(after Merkel).

The hepatic artery passes at first to the right along the superior order of the pancreas for a short distance, where it lies behind the

sser sac. It then turns forwards below the opening into lesser sac

D the upper border of the first part of the duodenum near the pylorus, od it subsequently ascends between the two layers of the lesser centum in front of the opening into lesser sac towards the porta epatis of the liver, on approaching which it divides into a right and tt hepatic branch. The vessel is accompanied by the hepatic symathetic plexus. As it ascends between the two layers of the lesser

A MANUAL OF ANATOMY

814

omentum it has the bile-duct on its right side, the portal vein beii behind both.

Branches .—These are right gastric, gastro-duodenal, and right ai left hepatic. The right gastric artery [pyloric artery), of small siz arises near the pylorus, and passes to the lesser curvature of t] stomach, where it divides into two branches. These lie between t] two layers of the lesser omentum, and supply offsets to the front ai back of the stomach. They anastomose with the two divisions of t] left gastric artery. The gastro-duodenal artery also arises near t] pylorus, and descends behind the first part of the duodenum, havii the bile-duct on its right and the portal vein behind it. Havii

reached the lower bord of the first part of tl duodenum, it occupies groove on the right of tl neck of the pancreas, ar here divides into its tv terminal branches—rig] gastro-epiploic and si perior pancreatico-duod nal. The right gastr epiploic artery passes froi right to left along tl greater curvature of tl stomach as far as i centre between the tv layers of the great< omentum, and its distr bution and anastomos< are similar to those of tl left gastro-epiploic arter The superior pancreatic 1 duodenal artery, havir divided into anterior an posterior branches, d< scends between the hea of the pancreas and tf second part of the duodenum, towards the lower end of which latter i anastomoses with the inferior pancreatico-duodenal branches of th superior mesenteric. It supplies the first and second parts of the due denum, and furnishes branches to the adjacent portion of the pancreas The hepatic branches are the terminal divisions of the trunk. The righ which is the larger, enters the porta hepatis at its right end, whilst th left, small in size, enters that porta at its left end, having previous! furnished a branch to the caudate lobe. The right branch gives ol the cystic artery, and this divides into two branches, superior an< inferior, which ramify on the upper and under surfaces of the gall bladder.

Fig. 473.—Plan of the Relations of Portal Vein, Hepatic Artery (HA), and Bile-Ducts Behind the Duodenum (Interrupted Line), and in Lesser Omentum.

RG, right gastric; and SD, supra-duodenal

arteries.

THE ABDOMEN

815

Variations of the Hepatic Artery. —A knowledge of the variations of the right nch of the hepatic artery is of considerable importance, owing to the frency with which operations are performed on the gall-bladder and the biliary sages. The right hepatic artery arises in about 20 per cent, of cases from superior mesenteric artery, while in about 4 per cent, of cases there are sent two right hepatic arteries, one arising from the main hepatic trunk, the er usually from the superior mesenteric artery. While the right hepatic

ry usually passes behind the common hepatic duct, it passes in about 12 per

t. of cases in front of it. The cystic artery most usually arises from the it hepatic, the most frequent site of origin being immediately after the artery made its appearance to the right of the duct. Accessory cystic arteries are infrequent. The left hepatic artery may arise from the left gastric artery, s important to remember that *the cystic artery, when it arises from an sual place—which is not very uncommon—always lies anterior to the duct nt).

The pre-pyloric vein passes from left to right, and opens into the ■tal vein near the pylorus.

The right gastro-epiploic vein passes from left to right, and opens d the superior mesenteric vein near its termination.

The superior pancreatico-duodenal vein takes up blood from the right 1 of the pancreas and from the duodenum, and opens into the superior senteric vein near its termination. Very constantly a small vein

n the pancreatico-duodenal area passes upwards in the greater

entum, lying anteriorly near its free margin, and opens into the ■tal vein.

The cystic vein usually ends in the right division of the portal

n.

All the veins which return the blood from the stomach, duodenum, lcreas, and spleen are destitute of valves, so that the blood can urgitate in cases of portal obstruction.

Coeliac Glands. —The glands of this group are numerous. They round the coeliac axis, and extend over the aorta as low as the T n of the superior mesenteric artery. They receive their afferent sels from the gastric, pancreatic, splenic, and hepatic glands, and ir efferent vessels either join the intestinal lymphatic trunk (or nks) of the superior mesenteric glands, or open independently into

cisterna chyli.

Gastric Lymphatic Glands. —These are arranged in two groups, >enor and inferior, the former lying along the lesser curvature of

stomach, and being almost entirely confined to the left part of this

'vature, and the latter below and behind the pyloric canal, forming

subpyloric and retro-pyloric groups. It is noteworthy that there

no glands in the neighbourhood of the fundus or along the greater vature until the pylorus is reached. They receive their afferent

'Sels from the stomach, and their efferent vessels pass to the coeliac -nds.

Pancreatic Glands. —These lie along the superior border of the icreas. They receive their afferent vessels from that organ, and their

• en t vessels pass to the coeliac glands.

Splenic Glands. —These are numerous, and are situated near the

8 i6

A MANUAL OF ANATOMY

hilum of the spleen in contact with the tail of the pancreas. T! receive their afferent vessels from the spleen, and their efferent vessi having been joined by some of those from the left half of the grea curvature of the stomach, pass to the cceliac glands.

Hepatic Glands. —These are situated between the two layers of 1 lesser omentum near the porta hepatis. They receive as affen vessels those of the deep lymphatics of the liver, which accompany i branches of the portal vein, and also some of the superficial lymphat of the inferior surface of the liver, and their efferent vessels pass to t coeliac glands.

All these glands are closely interconnected through anastomoses betwe their respective afferent and efferent vessels, and so infection of one group liable to be followed by infection of other groups.

Portal Vein. —This vein is formed by the union of the super mesenteric and splenic veins, and is about 3 inches in length, commences on a level with the body of the first lumbar vertel a little to the right of the middle line, where it lies behind the ne of the pancreas. It ascends behind the first part of the duodenu and then between the two layers of the lesser omentum in front the opening into lesser sac, where it has anterior to it the hepa artery and bile-duct, the artery being on the left of the duct. Wh the vessel arrives at the right extremity of the porta hepatis of the In it presents a slight enlargement, called the portal sinus , and then divic into two branches, right and left, the former being the larger a shorter of the two. The right branch, having received the cystic ve enters the right lobe of the liver. The left branch, having traversed t porta hepatis from right to left, and furnished branches to the quadrc and caudate lobes, crosses the fissure for ligamentum teres and enti the left lobe. As it crosses this fissure it is joined in front by t ligamentum teres of the liver, which is the remains of the umbili< vein of foetal life. Posteriorly, and slightly to the right of this poi] it is connected with the fibrous cord which represents the foetal duel venosus. The portal vein near the pylorus receives the prepyloric a left gastric veins. The distinctive character of the vessel is that behaves like an artery, its blood ultimately entering the intralobu] plexuses of the liver.

The sources from which the vein receives its blood are as follow (1) the stomach, (2) the small and large intestine, except a porti of the anal canal, (3) the pancreas, (4) the spleen, and (5) the ga bladder.

Summary of the Tributaries of the Portal Vein. —(1) The superior mesente: vein, which takes up (a) the right gastro-epiploic, ( b ) the pancreatico-duoder veins, ( c ) the jejunal and ileal veins, ( d) the ileo-colic, ( e ) the right colic, a (/) the middle colic. (2) The splenic vein, which takes up (a) the short gast veins, ( b ) the left gastro-epiploic, (c) many pancreatic veins, and ( d ) the infer mesenteric (as a rule), which in turn takes up the superior rectal, lower left col and upper left colic veins. (3) The prepyloric vein. (4) The left gastric ve (5) The cystic vein.

THE ABDOMEN 817

The portal vein and its tributaries are destitute of valves, so that blood can regurgitate in cases of portal obstruction.

Development of the Portal Vein. —-The lower portion of the vein results from union of the two vitelline veins. The upper portion is developed from the half of the lower venous ring and the right half of the upper venous ring, aed by the vitelline veins around the primitive duodenum.

For a description of the bile-duct, see p. 779.

/

Ileo-colic Vein

Bile-duct

ight Colic Vein.

Left Gastroepiploic Vein

Inf. Mesenteric Vein Sup. Mesenteric Art. Sup. Mesenteric Vein

Left Colic Vein

Inf. Mesenteric Artery

Gastro-epiploic'

Vein

ncreatico-duod.

Veins

!G. 474.— The Portal Vein and its Tributaries (after Spalteholz).

Kidneys. —The kidneys are two in number, right and left, and are ^ated deeply at the posterior part of the abdomen, where they lie md the peritoneum. They chiefly occupy portions of the epigastric ^ hypochondriac regions, but also extend slightly into the umbilical ^ lumbar regions. Relatively to the vertebral column they extend u the level of the upper border of the last thoracic vertebra to about centre of the body of the third lumbar, the right kidney being

52

8 i8

A MANUAL OF ANATOMY

usually somewhat lower than the left. The long axis of each 01 is directed downwards and slightly outwards, so that their upper c are rather nearer the middle line than the lower. The superior 1 of the right kidney is usually the lower border of the eleventh rib, wl that of the left is usually the upper border of the eleventh rib. feriorly the organs approach the iliac crests, from which they are dis about i to 2 inches, the right being the nearer of the two. Each kid

(Esophagus

— ' /

Diaphragm

Superior Suprarenal Arteries

Suprarenal Gland

Mid. Suprarenal Artery. Inf. Suprarenal Artery..

Renal Artery.

Inferior Vena Cava— Right Testicular Artery_

Right Ureter Aorta

Right Common Iliac... Artery

inf. Phrenic Ar

■ pjjjj - Coeliac Artery

.Superior Mesen Artery

Lumbar Artery

_ .Quadratus Lum Psoas Major

Inferior Mesent Artery

Iliacus

Left Testicular Artery

External Iliac Artery External Iliac Vein

Left Common Iliac Veir '* Median Sacral Artery

Rectum Bladder

Fig. 475. —Dissection of the Posterior Abdominal Wall.

is surrounded by a quantity of areolar and adipose tissues, constitut the paranephric fat, which is in turn enclosed by a fibrous tissue co\ ing known as the perirenal capsule (Gerota), and which, along with adjacent viscera, anchors the organ. The capsule is thicker beh than in front, and encloses the suprarenal gland as well as the kidfl The suprarenal gland is attached to the under surface of the diaphra by a strand of fibrous tissue forming a suspensory ligament. Ther no communication or connection between the glands of either s.

THE ABDOMEN

819

ie length of a kidney is about 4 inches, the breadth about 2\ inches, d the thickness about i| inches. The right kidney is usually shorter d broader than the fefT. The weight of the organ is about 5 \ ounces, form the kidney is bean-shaped. It presents two smooth surfaces, 0 extremities, and two borders. The anterior surface looks outads as well as forwards, and presents important visceral impressions, lilst the posterior surface looks inwards as well as backwards, and ssents muscular impressions. The extremities are enlarged and and, the superior more so than the inferior, the latter often assuming iomewhat pointed appearance. The lateral border has an inclination ckwards, and is convex and free. The medial border has an inclina

Fig. 476. —The Visceral Areas of the Kidneys. In this case the right renal vein was higher than usual.

n forwards, is concave, and is connected with the renal vessels and s pelvis of the kidney.

Relations — Anterior Surface of the Right Kidney. —This surface is erlapped by the right suprarenal gland for a very short distance at

upper and inner part. It presents three visceral areas—hepatic, odenal, and colic. The hepatic area lies somewhat obliquely, and uipies about the upper two-thirds, being in contact with the renal pression on the under surface of the right lobe of the liver. It is ^ered by peritoneum. The duodenal area corresponds with an elongated rrow strip lying close to the hilum, and reaching a little above and tow it. It is in contact with the posterior wall of the second part of ' duodenum, both being destitute of peritoneum. The colic area 5 below the hepatic, and, like it, is oblique. It is in contact with the

820

A MANUAL OF ANATOMY

upper end of the ascending colon and the right colic flexure withe the intervention of peritoneum. Between the lower part of the di denal and the colic impressions—that is, at the lower and inner p; of the anterior surface—there is often a small area covered by pi toneum which is in contact with a portion of the small intestine.

Anterior Surface of the Left Kidney. —This surface is overlaps by the left suprarenal gland for a somewhat greater distance at its up] and inner part than obtains on the right side. It presents five visce areas—splenic, gastric, pancreatic, colic, and jejunal. The sple\ area is situated at the upper and outer part close to the lateral bord

Fig. 477. —-Diagram showing the Relations of the Kidneys from Behini

R.L. Right Lung L L. Left Lung S. Spleen

R.K. Right Kidney L.K. Left Kidney IX. Ninth Rib X. Tenth Rib

XI. Eleventh Rib XII. Twelfth Rib

I. L. First Lumbar Vertebra

II. L. Second Lumbar Vertebra

III. L. Third Lumbar Vertebra

IV. L. Fourth Lumbar Vertebra V.L. Fifth Lumbar Vertebra

and is in contact with the renal surface of the spleen, the peritonei of the greater sac intervening. The gastric area , somewhat triangul; lies at the upper end between the splenic and suprarenal areas, and abo the pancreatic area. It is in contact with the postero-inferior surface the stomach, with the intervention of the peritoneum of the small s; The pancreatic area lies transversely below the gastric area, and exten as low as about the centre of the hilum. It is in relation with t posterior surface of the body of the pancreas and the splenic vessi without peritoneum. The colic area is situated at the lower and ou part, and is in contact with the left colic flexure and the commencemii of the descending colon, without peritoneum. # At the lower and ini'

THE ABDOMEN

821

rt there is a small area covered by peritoneum, which is related to a rt of the jejunum.

Posterior Surface. —This surface is readily recognized by observing at the pelvis of the kidney is posterior at the hilum. The inner rtion of it rests upon (a) the psoas major and its sheath, and (b) the is of the diaphragm. The outer portion rests, from above downirds, upon (a) the twelfth rib (in the case of the left kidney the venth rib also), (b) the diaphragm, and (c) the quadratus lumborum, vered by the anterior layer of the lumbar fascia. An important rgical relation of the upper part of this division of the posterior rface is that the pleura, in descending between the diaphragm and 3 twelfth rib, lies behind the kidney. Three nerves pass downwards d outwards behind the organ—namely, the subcostal, ilio-hypogastric, d ilio-inguinal. Kidneys hardened in situ usually show impressions educed by the last rib and the transverse processes of the upper nbar vertebrae.

The superior extremity is capped by the suprarenal gland, which also tends for a little over the anterior surface and adjacent portion of 3 medial border.

The lateral border, which is convex, rests on the posterior aponeurosis the transversus abdominis. The lateral border of the right kidney, er about its upper two-thirds, is in contact with the liver, whilst the eral border of the left kidney at its upper end is in contact with the

een.

Near this border a small collection of fat is often found which

upies the interval between the kidney and spleen on the left side,

d between the kidney and liver on the right side; this fat lies outside 3 fibrous capsule, and has been named the paranephric body to itinguish it from the paranephric fat which lies within the capsule. The medial border of the right kidney lies very near the inferior na cava, whilst that of the left is situated fully 1 inch from the rta. This border is concave, and presents a longitudinal fissure, Ued the hilum, which extends over about its middle third. It ssents two somewhat thick lips, anterior and posterior, and it leads a cavity within the organ, called the renal sinus. It transmits 3 following structures in order from before backwards: the branches the renal vein, the branches of the renal artery, with branches of the ial sympathetic plexus and lymphatics, and the pelvis of the kidney. The side to which a kidney belongs may be ascertained if the uctures at the hilum are in situ by noting that the hilum looks ^ards, that the ureter is posterior and inclines downwards. If, on 5 other hand, the structures at the hilum have been removed, the ^ to which a kidney belongs can usually be easily determined by ting that the anterior lip of the hilum shows two indentations [responding to the two prepelvic branches of the renal artery, [ereas the posterior lip only shows one indentation, which, moreer > points downwards, corresponding to the single retro-pelvic anch of the artery.

822

A MANUAL OF ANATOMY

Varieties—Form. —The kidneys may be much elongated, or somewhat rou or triangular. The lobulated condition (Fig. 478), which is characteristic the kidney in early life, may persist in the adult.

Size. —One kidney may be diminished in size, in which case there may t proportionate increase in the other organ.

Position. —It is very rare to find the kidneys higher than usual, but on( both not infrequently extend into the iliac fossa, or over the pelvic brim.

Number — Diminution .—One kidney (usually the left) may be entirely s pressed, in which case the solitary kidney usually occupies its normal posit:

and may, or may not, be of large s Increase .—The number may be creased to three, the additional or being lateral or median in position.

Horseshoe Kidney. —This condil is brought about by the fusion of lower parts of the organ, the c necting band of renal substance tending across the vertebral columi Preternatural Mobility. —The kid is usually anchored in its normal p tion by its capsule and the adjac viscera, but it is sometimes mova which may be due to one of 1 causes: (1) the capsule may be v loose, giving rise to the condit known as movable kidney ; or (2) organ may be attached to the poste: abdominal wall by a peritoneal fold, called the meso-nephron, in which case condition known as floating kidney occurs, this being said to be more frequ on the right side.

Movable kidney is more frequent in the female than in the male, a peculiar which has been attributed to the fact that in the female the renal fossae cylindrical, whereas in the male they are pear-shaped, with the narrow end be] (Southam).

For the structure and development of the kidney, see pp. 900 a

910.

Ureter.—The ureter is the excretory duct of the kidney, and conve the urine to the bladder. It is a cylindrical, thick-walled tube, li a goose-quill, its average length being about 12 inches, and its diame about \ inch. The ureter commences towards the lower end of t kidney, where it is the continuation of the pelvis, and terminates in t bladder. The pelvis is funnel-shaped, and flattened from before bac wards. It lies partly in the renal sinus, where it receives the calic and partly outside the hilum, where it lies behind the other transmitt structures. Its direction is downwards and inwards, and, havi: become narrow, it passes into the ureter towards the lower end of t kidney.

The ureter passes downwards and inwards behind the peritoneu in contact with the posterior abdominal wall. It rests at first up< the psoas major and its sheath, being here crossed superficially by t. testicular (or ovarian) vessels, which are taking a course downwar and outwards, and deeply by the genito-femoral nerve, which is taki a similar course. In this part of its course the right duct has the infer! vena cava near it on its inner side, whilst the left duct has the aor

Fig. 478. —Kidney of a Child shortly before Birth.

THE ABDOMEN

823

its inner side, but at some little distance. On the right side the )er end of the ureter lies behind the second part of the duodenum; the left side the ureter is crossed by the upper and lower left colic sels. The ureter next crosses the terminal part of the common iliac sry (or the commencement of the external iliac), after which it ers the pelvic cavity, the right ureter being crossed by the lower t of the root of the mesentery proper, and the left by a portion of pelvic meso-colon, its position here corresponding with that of the ^rsigmoid recess. In the pelvis the ureter first passes downwards,

kwards, and slightly outwards, lying in front of the internal iliac

sels and the sacro-iliac joint, following the curvature of the pelvic il in this region. It then turns forwards, downwards, and inwards, lg beneath the peritoneum, and crossing medially the obturator sels and nerve, and the umbilical artery. It subsequently passes rards to the bladder, being crossed medially by the vas deferens, ving arrived at the postero-lateral or ureteric angle of the bladder, it nmences to pierce the vesical wall anterior to the upper free end of the rinal vesicle, being here about 2 inches distant from its fellow, and )ut 1J inches from the base of the prostate gland. It now pursues an ique course through the wall of the bladder, lying in it for about nch, and finally opens into the interior by a very small slit-like jrture placed obliquely at one angle of the base of the trigonum

icse, where it is distant from its fellow and from the urethral orifice

)ut ij inches. In the female the ureter, in its pelvic course, passes ng the side of the cervix uteri and upper part of the vagina, being tant f inch from the cervix, and being here crossed antero-laterally the uterine artery.

Varieties. —(1) The pelvis may be absent, its place being taken by two, very rarely three, tubes. (2) Double Ureter. —The foregoing tubes may lain separate for some distance beyond the hilum, or even as low as the bladder, s giving rise to a double or a triple ureter. (3) Dilated Ureter. —This conon is liable to result in consequence of urethral stricture, enlarged prostate, L vesical calculus.

For the structure and development of the ureter, see pp. 907 I 910.

Suprarenal Glands (Suprarenal Capsules). —The suprarenal glands Irenals) are two in number, right and left, and are situated in the gastric region. Each is compressed from before backwards, broad m side to side, and set upon the superior extremity of the corrernding kidney, to which it is bound by connective tissue. Each ^sule encroaches upon the adjacent parts of the anterior surface i medial border of the kidney, the left being mainly situated upon the dial border. The dimensions of the organ are so variable that they 1 only be stated approximately as follows: the length is about ij 'hes, and the breadth rather less than 2 inches. The weight, on an erage, is about 4 grammes, and they are almost as large at birth as later years.

The right suprarenal gland is rather smaller than the left, and is

824

A MANUAL OF ANATOMY

quadrangular. It is pressed between the diaphragm and the post( surface of the right lobe of the liver, and its surfaces are anterior posterior, the former having an inclination outwards and the la inwards. The anterior surface , close to the inner border, is in con with the inferior vena cava, and elsewhere it is related to the poste surface of the right lobe of the liver. At its upper and inner part t is a small fissure, called the hilum, through which the single right su

CEsophagus

Diaphragm

Superior Suprarenal Arteries

Suprarenal Gland ..

Mid.Suprarenal Artery-. Inf. Suprarenal Artery-. Renal Artery.

Inferior Vena Cava..

Right Testicular Artery

Right UreterAorta—

Right Common Iliac Artery

■ill- Phrenic Arterie:

- Coeliac Artery

■'(/-.Superior Mesenl Artery

., - Lumbar Artery

- -Quadratus Lum

Psoas Major

_-Inferior Mesente Artery

—Iliacus --.Left Testicular 1

External Iliac Arte

External Iliac Vein

Left Common Iliac Vein Median Sacral Artery

Rectum bladder

F!g. 479. —Dissection of the Posterior Abdominal Wall.

renal vein emerges. The peritoneum gives a partial covering to t surface at its lower and outer part. The posterior surface is in conk with the diaphragm and the upper part of the anterior surface of i right kidney. The right coeliac ganglion lies on the inner side of i right gland.

The left suprarenal gland is somewhat semilunar. The anter surface is related above to the postero-inferior surface of the stoma] with the intervention of the lesser sac, which furnishes it with a p<

THE ABDOMEN

825

meal covering. Below this it is related to the posterior surface of the ody of the pancreas and the splenic vessels, without peritoneum, he hilum, through which the left suprarenal vein emerges, is situated t the lower and inner part of this surface. The posterior surface at its pper part is in contact with the left crus of the diaphragm, and below

rests upon The upper and inner part of the front of the left kidney,

s well as upon its medial border. Its upper lateral angle is usually in ontact with the apex of the spleen.

For the structure and development of the suprarenal gland, see . 897.

Abdominal Aorta. —The abdominal aorta commences at the aortic pening of the diaphragm on a level with the lower border of the body of he twelfth thoracic vertebra, where it lies in the middle line, and it sually terminates opposite the centre of the body of the fourth lumbar * ertebra, a finger’s breadth to the left of the middle line, by dividing into he right and left common iliac arteries. The position of the bifurcation lay be indicated in one of two ways as follows: (1) by taking a point inch belo\v and to the left of the umbilicus; or (2) by taking a point 1 the line which connects the highest parts of the iliac crests a finger’s •readth to the left of where it intersects the linea alba. The bifurcaion may take place a little lower down or higher up than the normal wel. The length of the vessel is about 5 inches. It occupies the pigastric and umbilical regions, where it lies very deeply behind the •eritoneum, and its direction is downwards with a slight inclination to he left.

Relations — Anterior .—The direct anterior relations, from above lownwards, are as follows: the origins of the phrenic arteries, the oeliac artery, coeliac glands, and cceliac plexus, the ascending layer f the transverse meso-colon, the pancreas and splenic vein, the root I the superior mesenteric artery, the third part of the duodenum nd left renal vein, the origins of the testicular (or ovarian) arteries, he aortic plexus, the pre-aortic group of lumbar glands, the peritoneum »f the greater sac, and the origin of the inferior mesenteric artery, die more remote anterior relations are the lesser omentum, stomach, ransverse colon with its meso-colon, coils of the small intestine, root >f the mesentery proper, and greater omentum. Posterior .—The disc >etween the twelfth thoracic and first lumbar vertebrae, the bodies and liscs of the upper four lumbar vertebrae, and the anterior longitudinal igament, the left lumbar veins, and the origins of the lumbar and nedial sacral arteries. Right .—The right crus of the diaphragm, vith the cisterna chyli and vena azygos lying deeply between the vessel aid the right crus, the cisterna chyli being nearest the aorta, and lightly covered by it; and the inferior vena cava. Left .—The left 'rus of the diaphragm, the left coeliac ganglion, the terminal portion >f the third part of the duodenum, and the left sympathetic gangliated runk.

Branches. —These are nine in number, and are arranged in two Toups, visceral and parietal, four of them being single and five arranged

826

A MANUAL OF ANATOMY

in pairs. The four single branches are the coeliac artery, super mesenteric, inferior mesenteric, and median sacral. The five pa are the inferior phrenic, middle, suprarenal, renal, testicular (ovari

Fig. 480.—Dissection of Structures on Posterior Wall. Inferior mesenteric artery is laid down (with some of its branches) in positioi

in the female), and the lumbar. Excluding the lumbar arteries, tb order of origin of the branches is as follows: (1) phrenic, (2) coelia artery, (3) superior mesenteric and (4) middle suprarenal, both 0 the same level, (5) renal, (6) testicular (or ovarian), (7) inferior meser

THE ABDOMEN 827

c, and (8) median sacral. In what follows, the letter P after an sry signifies parietal, and V visceral.

The phrenic arteries (P) are two in number, right and left. They se, either separately or by a common trunk, from the front of the ta, as soon as the vessel has passed through the aortic opening of diaphragm. They at once diverge, each passing outwards and vards over the crus of the diaphragm, the right vessel lying behind inferior vena cava, and the left behind the oesophagus. Each ends dividing into two branches, medial and lateral. The medial branch ises forwards and inwards in a curved manner in front of the central don, and anastomoses with its fellow of the opposite side, and the sculo-phrenic of the internal mammary. The lateral branch passes wards, and anastomoses with the musculo-phrenic and the lower srcostal arteries. Each phrenic artery furnishes a superior supraal branch (or branches) to the suprarenal gland, the right vessel d giving off a few branches to the inferior vena cava, whilst the

supplies a few branches to the oesophagus.

The right phrenic vein opens into the inferior vena cava, and the terminates in the left suprarenal vein, left renal vein, or inferior 1a cava.

The cceliac artery (V) and superior mesenteric artery (V) will be ind described on pp. 811 and 796.

The middle suprarenal arteries (V) are of small size, and are two in mber, right and left, each arising from the side of the aorta on a el with the origin of the superior mesenteric artery. The vessel sses outwards and upwards over the crus of the diaphragm to the Drarenal gland, in which it anastomoses with the superior suprarenal the phrenic and the inferior suprarenal of the renal.

The right suprarenal vein opens into the inferior vena cava, and the t into the left renal vein.

The suprarenal veins originally open mainly into the subcardinal system, e right suprarenal vein thus opens into the upper segment of the inferior 1a cava (above the right renal vein). The left suprarenal vein, as the remnant the left subcardinal vein, joins the left renal vein.

The renal arteries (V) are remarkable for their large size, and are 0 in number, right and left. They arise from the side of the aorta out \ inch below the superior mesenteric on a level with the body the first lumbar vertebra, the right artery being usually a little ver than the left. They form right angles with the aorta, and cross 3 crura of the diaphragm on their way to the hila of the kidneys, e right vessel passing behind the inferior vena cava, second part of e duodenum, and head of the pancreas, whilst the left passes behind e body of the pancreas. Each vessel has its own vein in front of it, d the aortico-renal ganglion lies over its root. On approaching the lal hilum each vessel divides into three or four branches, one of which, town as the retro-pelvic branch, usually passes behind the pelvis of e kidney, whilst the others lie between the renal vein in front and the

828

A MANUAL OF ANATOMY

pelvis behind. For the subsequent distribution of the branches the kidney, see p. 904.

Before breaking up into its proper renal branches the vessel g] off an inferior suprarenal artery to the suprarenal gland, paranep , branches to the capsule, and ureteric to the upper part of the ureter

Varieties. —(1) Very often there is an accessory renal artery present, ari close to the main vessel, and usually above it. (2) The renal artery may di 1 into its renal branches close to its origin. (3) There may be an aberrant r artery, which may arise from the phrenic, testicular (or ovarian), inferior me

Fig. 481.—To show the Arrangement of Veins joining to form the Pori

Vein, and their Relations to the Aorta.

teric, common or external iliac, or median sacral. An aberrant renal arte when present, is usually confined to one side, more frequently the right; 1 artery more often passes behind the ureter than in front (Hutchinson). (4) cases of variations, or even in the normal condition, one or more of the rei branches may fail to enter the hilum, and may pierce the kidney on its anter surface, or near the upper or lower end.

The renal veins, like the arteries, are of large size. Each lies front of its artery, and receives tributaries from the paranephric i and the upper part of the ureter. The vessels are tributaries of t inferior vena cava, which they join almost at a right angle, the k

THE ABDOMEN

829

ittle higher than the right. The left vein crosses in front of the ta, taking up in its course the left suprarenal and left testicular ovarian) veins. In some cases there is a single semilunar valve at

lower part of the opening of each renal vein into the inferior vena

r a.

The renal veins originally join the periganglionic veins. Subsequently the it renal vein opens into the junction of the upper and lower segments of the

rior vena cava. When the left cardinal vein becomes obliterated, in great

t the left renal vein becomes continuous with the primitive inferior vena cava.

mesial portion of the left renal vein is developed from the pre-aortic venous

ms. For details see Chapter XIII.

The testicular arteries (spermatic arteries) (V) are two in number, ht and left, and they arise from the front of the aorta about 1 inch ow the renal arteries. If they arise separately they are close to each ler, but they sometimes spring by a common trunk. They are long, nder, somewhat tortuous vessels, which at once diverge, each passing iquely downwards and outwards behind the peritoneum. In this irse the vessel rests upon the aorta for a short distance, and then on the psoas major and its sheath, where it crosses the ureter, e right artery passes in front of the inferior vena cava and behind i terminal part of the ileum, whilst the left passes behind the left ic vessels and the iliac part of descending colon. Subsequently the

ery, on its way to the deep inguinal ring, lies upon the terminal part

the external iliac. At the deep ring it approaches the vas deferens form, with other structures, the spermatic cord. The vessel then sses through the deep inguinal ring, along the inguinal canal, and rough the superficial inguinal ring into the scrotum, where it divides

o glandular and epididymal branches. In the abdomen the testicular

ery furnishes ureteric branches to the ureter, and in the scrotum

skives off cremasteric branches to the coverings of the spermatic cord, rich anastomose with the cremasteric branch of the inferior epigastric, iring foetal life the vessel is very short, and takes a transverse course the testis, which is then lying near the kidney. As the testis, hower, descends into the scrotum the vessel gradually becomes much rngated.

Varieties. —(1) One or both testicular arteries may be absent, in which cases

• testis is supplied chiefly by the artery to the vas deferens. (2) A testicular

ery may arise from a renal artery.

The testicular veins (spermatic veins) spring from the pampiniform 2 xus of the spermatic cord at the deep inguinal ring, and are at first r o in number on each side, which lie one on either side of the correonding artery. They subsequently unite to form a single vessel, rich on the right side opens at an acute angle into the inferior vena va, and on the left at a right angle into the left renal vein. There is ually a valve at the point of termination of each vein, though this ay be absent. In the left testicular vein, where it joins the left renal

in, the valve directs the current of blood entering by the testicular

in in the direction of the inferior vena cava. It also prevents the

830

A MANUAL OF ANATOMY

blood in the left renal vein from entering the testicular vein by direc the current over the mouth of the latter vessel. The left testici vein is rather longer than the right.

The testicular (or ovarian) veins drain the embryonic gonad into the cardinal venous system. Part of the abdominal vena cava (Chapter XII) is veloped from the subcardinal vein, so that the right testicular vein opens into ■ On the left side the subcardinal system drains by pre-aortic anastomosis the right subcardinal (inferior vena cava), the anastomosis forming part of left renal vein; hence the left testicular vein or ovarian vein opens into the renal vein.

The ovarian arteries (V) in the female take the place of the testici arteries in the male, and their course and relations in the abdor correspond with those of the testiculars. The ovarian arteries ; however, shorter than the testiculars, and they do not pass out throi the inguinal canal, but enter the pelvis by crossing the commencem of the external iliac artery. In the pelvis each vessel becomes v tortuous, and passes between the two layers of the broad ligamen the uterus to be distributed to the ovary. In the abdomen the art supplies branches to the ureter, and in the pelvis it furnishes the folli ing offsets: tubal to the uterine tube; a uterine branch to the side of uterus; and a ligamentous branch to the ligamentum teres of the utei which it accompanies as far as the inguinal canal. The ovarian arter like the testicular, are very short and transverse in direction dur foetal life, when the ovary occupies a position similar to that of testis. They, however, gradually become elongated as the ov; descends to its future abode in the pelvis.

The ovarian veins spring from the ovarian or pampiniform pie: between the two layers of the broad ligament close to the ovary. A 1 emerging therefrom their subsequent course and mode of terminat resemble those of the testicular veins.

For the inferior mesenteric artery (V) and vein, see p. 801; the median sacral artery (P) and vein, see p. 946; and for the lum' arteries (P) and veins, see p. 847.

Inferior Vena Cava. —The inferior vena cava commences oppos the upper border of the body of the fifth lumbar vertebra a little the right of the middle line, where it is formed by the union of 1 right and left common iliac veins, and it terminates at the poste inferior angle of the right atrium of the heart. It ascends along 1 right side of the aorta, resting upon the anterior and right aspects the lumbar vertebrae as high as the level of the second. Beyond t point it diverges from the aorta, and is supported by the right cj of the diaphragm. It then occupies the fossa for vena cava on 1 posterior surface of the right lobe of the liver. On leaving this fossa passes through the caval opening in the central tendon of the diaphrag and almost immediately afterwards opens into the postero-infer angle of the right atrium of the heart. As the vein passes through i caval opening, its walls are connected with the margins of that openii and so the patency of the vessel is maintained.

THE ABDOMEN

831

Relations — Anterior .—From below upwards, the right common c artery, lower part of the root of the mesentery proper, right ticular (or ovarian) vessels, third part of the duodenum, head of

pancreas, origin of the portal vein, first part of the duodenum,

ming into lesser sac, and posterior surface of the liver. Posterior .— e bodies, discs, and anterior longitudinal ligament of the lower three ibar vertebras, the corresponding right lumbar vessels, inner border

ug. 482. —Scheme of the Inferior Vena Cava and its Tributaries.

the right psoas major and its sheath, right sympathetic gangliated ink, right renal artery, right coeliac ganglion, right crus of the diaragm, right suprarenal gland, and right phrenic artery. Right .— 3 m below upwards, the right ureter and the medial border of the ht kidney. Left .—From below upwards, the aorta and the right is of the diaphragm.

Tributaries. —These are as follows: the right and left common •c veins, right and left lumbar veins, the right testicular (or ovarian)

832

A MANUAL OF ANATOMY

vein, the right and left renal veins, the right suprarenal vein, the ri^ phrenic vein (and sometimes the left), and the hepatic veins at i fossa for vena cava of the liver.

Chief Varieties. —(1) The vessel may be found on the left side of the ao: in its lower part, in which cases it subsequently crosses that vessel to take its usual position on its right side. This may be due to a transposition of visce or to a permanent patency of the lower part of the left cardinal vein of foetal li (2) The two common iliac veins, instead of uniting at the level of the fifth luml vertebra, may run up on either side of the aorta until they have received th renal tributaries, after which the left crosses the aorta to join the right, a form the inferior vena cava about the level of the first lumbar vertebra. (3) T. inferior vena cava in very rare cases may terminate in a large azygos vein, a through means of that in the superior vena cava. Under these circumstam the hepatic veins open into the right auricle of the heart.

Development .—The postrenal segment of the inferior vena cava is develop from the lower portion of the right supracardinal or periganglionic veins. 1 prerenal segment is developed from (1) the upper portion of the right subcardii vein; (2) the hepatic sinusoids; and (3) the common hepatic vein (Lewis). £ development of vessels, in Chapter XIII.

Aortic Lymphatic Glands. —These glands are very numerous, ai are arranged in four groups , which lie around the abdominal aori The groups are spoken of as pre-aortic, juxta-aortic, right and left, a] retro-aortic, respectively.

Pre-aortic Glands. —These are usually disposed in three setsnamely, (1) cceliac glands, which constitute a very distinct set aroui the origin of the coeliac artery; (2) superior mesenteric glands, in tl region of the origin of the superior mesenteric artery, and along t] trunk of the vessel; and (3) inferior mesenteric glands,in the region the origin of the inferior mesenteric artery.

The afferent vessels of the pre-aortic glands are derived from tl following sources:

1.

2.

3 4 5 6 .

Rectum.

Pelvic colon.

Descending colon.

Transverse colon.

Ascending colon.

Caecum.

13. Juxta-aortic

7. Vermiform appendix.

8. Small intestine.

9. Stomach.

10. Liver.

11. Pancreas.

12. Spleen, glands.

The coeliac glands more particularly receive their chief affere\ vessels from the following glands:

1. Gastric glands. 3. Hepatic glands.

2. Retro-pyloric glands. 4. Splenic glands.

5. Pancreatic glands.

The efferent vessels of the pre-aortic glands usually unite to fori one trunk, called the intestinal lymphatic trunk, which with the lumbc lymphatic trunks from the juxta-aortic glands forms the cisterna chyl A few of them pass to the retro-aortic glands.

THE ABDOMEN

833

Tuxta-aortic Glands (Lateral Lumbar Glands). —These are disposed wo groups— right and left. The right glands lie both in front of, behind, the inferior vena cava, whilst the glands of the left side n a single chain on the left side of the abdominal aorta, rhe juxta-aortic glands of either side receive their afferent vessels a the following sources:

1. Common iliac glands. 4. Suprarenal gland.

2. Testis. 5. Kidney.

3. Ovary, uterine tube, and ad- 6. Abdominal wall.

jacent half of body of uterus.

rheir efferent vessels for the most part unite on either side to form mbar lymphatic trunk, right and left, which opens into or forms the -rna chyli. Some pass to the pre-aortic glands, and others to the o-aortic glands.

Retro-aortic Glands. —These glands are about four in number, and j lie behind the abdominal aorta in front of the bodies of the third fourth lumbar vertebrae. Their afferent vessels are derived from pre-aortic and lateral aortic glands, as well as from the vertebral ies and ligaments to which they are related. Their efferent vessels

e to form a single trunk, called the intestinal lymphatic trunk , which

is into the cisterna chyli.

Diaphragm — Origin. — Sternal Portion. —By two fleshy slips from back of the xiphoid process close to its lower end. Costal Portion.— six fleshy slips at either side from the inner surfaces of the lower costal cartilages, which interdigitate with slips of the transversus ominis. Lumbar Portion.— From the lateral and medial arcuate nents, and from the anterior surfaces of the bodies of lumbar ebrae, as well as the intervertebral discs and anterior longitudinal nent, by two crura, the right crus reaching usually as low as the between the third and fourth lumbar bodies, and the left as low as disc between the second and third.

T nsertion. —The central tendon on all sides.

V erve-supply .—The right and left phrenic nerves, each of which figs chiefly from the anterior primary division of the fourth cervical r e, and usually receives a branch from the fifth, and sometimes from third. Each phrenic nerve, on approaching the diaphragm, des into a dorsal and two ventral branches, the dorsal branch being ributed to the lumbar portion, the two ventral branches accomping the two branches of the phrenic artery. On the right side, re a communication takes place between the right phrenic nerve and right phrenic sympathetic plexus, a small ganglion, called the \lion diaphragmaticum, is situated at the place of communication, milar connection is established on the left side, but no ganglion is ent.

Arterial Supply. —(1) The phrenic branches of the abdominal (2) the pericardiaco-phrenic and musculo-phrenic, both branches be internal mammary of each side; (3) the phrenic branch of the

53

834

A MANUAL OF ANATOMY

superior epigastric of the internal mammary of each side; and (4) bram from the lower intercostal arteries.

Lymphatics .—These are arranged in two groups, one on the thor; aspect, the other on the abdominal aspect; there is a free communicai between the two groups on each side of the middle line, but not so : between the groups of the two sides. The free communication refei to is promoted by the movements of respiration, for during inspirat when the pressure in the thorax is reduced, and that in the abdoi is increased, the lymph flows from the abdominal to the thor surface of the diaphragm, while during expiration the movemen reversed. The lymph is drained from the diaphragm superiorly by

Xiphoid Process / y Sternal Origin

. Central Tendon

Vena Caval Opening ^

CEsophageal x Opening

Lateral Arcuate Ligament

Aortic Opening

r

Quadratus Lumborum / j

Medial Arcuate Ligament

Psoas Major

Left Crus

Right Crus

Intervertebral Disc

Fig. 483. —The Diaphragm (Inferior View).

supradiaphragmatic glands, which send their efferents to the intei mammary, posterior mediastinal, and intercostal glands, and from diaphragm inferiorly by the upper juxta-aortic glands of either si the pre-aortic and oesophageal glands. The lymphatics of the vari viscera in relation with the diaphragm are separate from those of diaphragm except in the case of the liver.

Action .—The diaphragm by its contraction increases the vert] diameter of each half of the thorax, and is therefore a muscle of spiration. The middle portion of the central tendon is fixed by rea: of the fibrous portion of the pericardium, which is implanted into being connected above with the deep cervical fascia. The fle;

THE ABDOMEN

835

rtion, however, becomes flattened, and descends towards the abdomen, placing the viscera, and so increasing the vertical diameter of each If of the thorax. The diaphragm also elevates the lower ribs, except

last, which is fixed by the quadratus lumborum muscle.

The muscular fibres pass in an arched manner upwards and inwards to the Aral tendon, upon which they converge from all points. The sternal portion separated on either side from the costal portion by a small interval occupied areolar tissue, through which the superior epigastric vessels and some of the •erficial lymphatics of the upper surface of the liver pass. Above and below 3 interval are the pleura and peritoneum respectively. In this situation a phragmatic hernia may take place, involving one or other of the abdominal cera. Between the lowest costal fibres of the corresponding lateral arcuate iment there is sometimes another areolar interval of small size. The crura strong, thick, musculo-tendinous bundles disposed vertically, the left being

smaller, shorter, and more posterior of the two. Each crus is fleshy laterally,

1 strongly tendinous medially, the lower extremity of each being entirely idinous. On a level with the lower border of the body of the twelfth thoracic •tebra the inner tendinous fibres of the crura are connected by a fibrous band, led the median arcuate ligament, which lies in front of the aorta. The muscular res of the crura pass upwards in a diverging manner to be inserted into the iterior border of the central tendon. The innermost muscular fibres on either e, reinforced by fibres springing from the median arcuate ligament, decussate ore reaching the central tendon, and enclose between them the oesophageal ming. In the decussation the bundle derived from the right crus passes in nt of that from the left, which latter is of small size.

The central tendon is also called the cor diform or trefoil tendon, is much elongated from side to side, convex in front, and conve behind. It is divided into three lobes or alse—right, median, d left, of which the right is the largest, and the left the smallest d narrowest.

The diaphragm presents three foramina—namely, aortic, vena val, and oesophageal.

The aortic opening is situated in the middle line between the upper rtions of the crura, and in front of the disc between the bodies of e twelfth thoracic and first lumbar vertebrae. It is bounded on her side by a crus, in front by the median arcuate ligament, and hind by the anterior longitudinal ligament of the vertebral column, is therefore not really an opening in the diaphragm, but is situated hind it. It transmits the aorta, thoracic duct, and azygos vein, in is order from left to right.

The vena caval opening is situated in the central tendon close to its sterior border and at the junction of the right and median lobes, is somewhat four-sided, with rounded angles, and transmits the ferior vena cava, twigs from the right phrenic nerve, and some of e deep lymphatics of the liver.

The oesophageal opening is situated in the fleshy-part of the muscle, is elliptical, and lies in front, and a little to the left, of the aortic 'ening, being separated from it behind by the inner decussating >res of the crura. It transmits the oesophagus, the right and left gus nerves, and the oesophageal branches of the left gastric

836

A MANUAL OF ANATOMY

In addition to the foregoing foramina, the diaphragm presents certain sr fissures as follows: each crus is pierced by the greater and lesser splanct nerves, and sometimes by the lowest. The left crus is also pierced by the infe vena hemiazygos vein. The musculo-phrenic artery pierces the costal port and the branches of the phrenic nerve are also transmitted through the mus A small vein pierces the central aponeurosis on the left side at a point co sponding to that of the vena caval opening on the right side; it is believed represent the left vitelline vein of the embryo.

The arcuate ligaments are five in number, as follows: lateral, rij and left; medial, right and left; and median. The lateral arcu ligament is a thickening of the upper part of the anterior wall of sheath of the quadratus lumborum, and extends from the last to the tip of the transverse process of the first lumbar vertebra. 1 subcostal artery and anterior primary division of the last thora

Central Tendon

Fig. 484.—The Diaphragm (Superior View) (after L. Testut’s

‘ Anatomie Humaine ’).

nerve pass downwards and outwards behind it. The medial arcui ligament is a thickening of the upper part of the sheath of the psc major, and extends from the tip of the transverse process of the fi lumbar vertebra to the side of its body, and sometimes to that of 1 second vertebra. The gangliated trunk of the sympathetic pas: into the abdomen behind it, and sometimes the lowest splanchnic ner The median arcuate ligament is a fibrous band which connects t innermost tendinous fibres of the crura on a level with the lower bore of the body of the twelfth thoracic vertebra, and arches over the aort

Relations of the Diaphragm — Superior .—The right and left pleurae with lungs, and the pericardium with the heart. Inferior .—The peritoneum, exo opposite the bare area of the posterior surface of the liver; the liver with j falciform, coronary, and right and left triangular ligaments; the stomach; spiel! pancreas; kidneys; and suprarenal glands.

THE ABDOMEN

837

Development. —Ihe diaphragm is developed in four parts—ventral and dorsal l lateral (R. and L.).

The ventral part, central, is the first to appear, and is developed from the turn transversum. It lies between the pericardial and peritoneal cavities, l has the primitive oesophagus passing on its dorsal aspect in the mid-line, with ericardio-peritoneal passage on each side of this ; these are the primitive pleural

Right Lymphatic Duct

Right Innominate Vein' 1

Superior Vena Cava-; Right Superior Intercostal Vein

Vena Azygos ~ v

Thoracic Duct -

Posterior Intercostal Glands

Cistern a Chyli

Right Ascending Lumbar Vein

Inferior Vena Cava

Thoracic Duct

- Left Innominate Vein

- Left Superior Intercostal Vein «- • Arch of Aorta

- Superior Vena Hemiazygos

/If/lljh

Upper Transverse Azygos Vein

Lower Transverse Azygos Vein Ninth Intercostal Vein Inferior Vena Hemiazygos

Left Subcostal Vein Quadratus Lumborum

1 i.

ji-r'rf- Left Ascending Lumbar Vein

Abdominal Aorta 1 Iliac Crest - Psoas Major

— Iliacus

'- Common Iliac Arteries

Fig. 485.— The Thoracic Duct, Azygos Veins, and Posterior

Intercostal Glands.

hes, from which the secondary pleurae will start their extension into the 7-wall.

iach of the lateral parts is brought into existence as the result of extension of sural sac. This, enlarging in the body-wall, splits this into inner and outer rs. The extension of the cavity caudally brings the inner layer into evidence Fe pleuroperitoneal membrane, separating the growing pleura from the ttnmal cavity. Extension of muscle cells from the central part into these

838

A MANUAL OF ANATOMY

lateral membranes makes them into the lateral portions of the diaphragm, fusion between these pleuro-peritoneal membranes and the ventral part o diaphragm may be incomplete on one or other side, in which cases a commu tion is left between the thoracic and abdominal cavities, through which a phragmatic hernia may occur. The persistent opening is just lateral to the si renal gland.

The central dorsal part of the diaphragm is formed from the common d mesentery, or meso-oesophagus (see p. 61), into which muscular fibres ex to form the crura.

Gangliated Trunk of the Sympathetic. —This cord enters the al men behind the inner portion of the medial arcuate ligament. It i descends along the inner border of the psoas major, where it lie front of the bodies of the lumbar vertebrae, and having passed be] the common iliac artery, it enters the pelvis. The right lumbar tr is under cover of the inferior vena cava, whilst the left lies a little tc left of the aorta, and the lumbar vessels of each side pass beneath corresponding cord. Each cord usually possesses four ganglia.

Branches. —These are arranged in two sets—namely, rami c municantes, and branches of distribution. The rami communicai which are long, are of two kinds, white and grey, the latter b

the more numerous. The u rami are composed of me< lated nerve-fibres, and are more than three in num They are derived from anterior primary division: the first two or possibly tl lumbar nerves, and procee< the ganglia. The grey r pass from all four ganglia join the anterior primary d sions of the five lumbar ner One or more rami may div and so pass to one or ir ganglia. Both white and g rami pass together bene the fibrous arches of the ps Fig. 485A.— Two Common Modes of Origin major in company with of the Thoracic Duct (after Rouviere). lumbar vessels, and the C(

L, lumbar ducts; I, intestinal duct. In one case there is a definite cisterna (C). Some juxta-aortic glands are seen below.

munications with the lum nerves are established d to the intervertebral forami The branches of distribul proceed partly from the ganglia and partly from the connecting cc and are distributed to the coats of the aorta, the bodies and ligame of the lumbar vertebrae, and the hypogastric plexus, the last branc crossing the common iliac artery.

Cisterna Chyli (Receptaculum Chyli). —This is the dilated commer ment of the thoracic duct. It is situated deeply at the upper pari

THE ABDOMEN

839

posterior abdominal wall in front of the bodies of the first and second bar vertebrae, where it has the aorta on its left side and slightly in t, and the vena azygos on its right side. It is overlapped by the t crus of the diaphragm. It is somewhat elliptical, being about

h broad at its widest part, and about 2 inches in length. Superiorly

ccomes narrow, and is continued into the thoracic duct, which

rs the thorax through the aortic opening of the diaphragm. It

ives the following efferent vessels from below upwards: the right left lumbar lymphatic trunks from the juxta-aortic glands, which its lower narrow end; the efferent vessels from the retro-aortic ids; and the intestinal lymphatic trunk (or trunks) from the preic glands.

fVzygos Veins. —These are three in number—namely, the vena

• os, the inferior vena hemiazygos, and the superior vena hemi*os.

rhe vena azygos usually commences in the right ascending lumbar , which is formed by longitudinal anastomosing branches passing veen the lumbar veins in front of the lumbar transverse processes, so disposed as to form one vein which communicates with the rior vena cava, and with one or other of the following veins of the t side: the common iliac, the internal iliac, the ilio-lumbar, or the ral sacral. Sometimes, however, the azygos vein springs from the

erior aspect of the inferior vena cava close to the right renal vein,

rom that renal vein itself, or from the first right lumbar vein. It

nds upon the body of the first lumbar vertebra, where it lies on the

it side of the cisterna chyli under cover of the right crus of the )hragm, and it enters the thorax through the aortic opening of t muscle. For its subsequent course in the thorax, where it ninates in the superior vena cava, see the section of the thorax. The inferior vena hemiazygos commences in the left ascending bar vein, through which it has communications similar to those he azygos vein. It may, moreover, spring from the left renal vein, he first left lumbar vein. It enters the thorax through the left crus he diaphragm, and subsequently terminates in the azygos vein.

The azygos and inferior hemiazygos veins are persistent portions of right and left cardinal veins of foetal life.

The azygos and inferior hemiazygos veins, through their connections h the ascending lumbar veins, establish communications with the

rior vena cava, and with the common iliac veins or some of their

•utaries. They therefore form important channels by which a siderable quantity of blood is returned from the lower limbs and Lominal wall in cases of obstruction of the inferior vena cava.

The superior vena hemiazygos will be found described in connection h the thorax.

Fasciae of the Posterior Abdominal Wall—Iliac Fascia. —This fascia ers the iliacus and psoas major muscles. Above the level of the c crest it is related only to the psoas major, and the part covering t muscle is spoken of as the psoas sheath. Superiorly it forms the

840

A MANUAL OF ANATOMY

medial arcuate ligament, which extends between the tip of the lumbar transverse process and the side of the body of that verte Medially it is attached to {a) the intervertebral discs and contigi margins of the bodies of the lumbar vertebrae, and (b) the fibrous ar over the lumbar vessels opposite the centre of each lumbar b< Laterally , near the tips of the lumbar transverse processes, it ble with the anterior layer of the lumbar fascia which covers the quadr; lumborum. Below the level of the iliac crest the iliac fascia covers iliacus as well as the psoas major. This part of it is known as fascia iliaca , and it passes uninterruptedly from the iliacus on to psoas major. Laterally it is attached to the anterior two-thirds of iliac crest immediately within its inner lip, and 'medially to the al the sacrum and the iliac portion of the pectineal line. Inferiorl is disposed in the following manner: along the outer half of the ingu ligament on its deep aspect the fascia is firmly attached to that 1 ment, and joins the fascia transversalis, the two constructing a a which contains the first part of the deep circumflex iliac artery, posite the external iliac vessels the fascia passes downwards bet them and the inguinal ligament to form the posterior wall of the fern* sheath. Medial to the external iliac vessels it is continuous with pubic lamina of the fascia lata, as that covers the upper part of pectineus. From the point of junction between the iliac fascia and pubic fascia lata an intermuscular septum (ilio-pectineal) passes bs wards between the pectineus and the psoas major to be attached to ilio-pubic eminence and the front of the capsular ligament of the 1 joint.

The importance of the iliac fascia has reference to the course taken by in cases of lumbar (psoas) abscess. The pus cannot pass outwards over quadratus lumborum without bursting through the psoas sheath, because psoas sheath is bound down to the anterior wall of the fascia covering quadratus lumborum at the outer border of the psoas muscle. It cannot ] across the vertebral column on account of the attachments of the psoas she in that situation. The usual course, therefore, taken by the pus is to dif itself downwards within the psoas sheath. On reaching the iliac fossa it 1 diffuse outwards beneath the iliac fascia as that covers the iliacus muscle, br cannot enter the pelvic cavity on account of the attachment of the iliac fa to the pelvic brim, unless it bursts through the psoas sheath. Consequen the pus usually treks along the psoas major within its sheath, and, pas: behind the inguinal ligament and the femoral sheath containing the fem vessels, it may point in the region of the saphenous opening on a level with lesser trochanter, simulating a femoral hernia, or it may accompany one or ol of the large vessels in this region, more particularly perhaps the medial fem' circumflex artery, which may conduct it to the back and inner side of the th

Lumbar Fascia (Aponeurosis). —This is situated between the ] rib and the iliac crest, and is often regarded as the posterior aponeurc of the transversus abdominis muscle. Strictly speaking, only middle layer is the posterior aponeurosis of this muscle. When follo\ backwards it divides into three layers—anterior, middle, and poster: The anterior layer, which is thin, covers the quadratus lumbort and is attached medially to a vertical ridge on the anterior surface

THE ABDOMEN

841

e transverse processes of the lumbar vertebrae some distance medial their tips. In this situation it is interposed between the quadratus mborum and psoas major, and receives the iliac fascia which forms e psoas sheath. At the outer border of the quadratus lumborum it ins the middle layer, and is here also continuous with the fascia transTsalis. Superiorly it forms the lateral arcuate ligament, which tends between the last rib and the tip of the first lumbar transverse ocess. Interiorly it is attached to the ilio-lumbar ligament and the ntiguous part of the inner lip of the iliac crest. The middle layer, tiich is of considerable strength, is attached medially to the tips of e lumbar transverse processes, and laterally, at the outer border of e quadratus lumborum, it is joined by the anterior lamina, whilst the outer border of the sacro-spinalis it receives the posterior layer.

Sacro-spinalis Transverse Process

Body'of 3rd Lumbar Psoas Major, covered by

Vertebra Psoas Fascia

Fig. 486. —Diagram of the Lumbar Fascia.

iperiorly it is attached to the lower border of the last rib, and inriorly to the back part of the summit of the iliac crest. The middle yer lies between the quadratus lumborum and the sacro-spinalis. ie posterior layer, which is also very strong, is attached to the spinous ocesses of the lumbar and sacral vertebrae, and the posterior fourth the outer lip of the iliac crest. It lies behind the sacro-spinalis, at the her border of which it blends with the middle layer, and so the uscle is enclosed in a sheath. The posterior layer is joined by the scia covering the latissimus dorsi, and affords attachment to the tter muscle and serratus posterior inferior.

Muscles of the Posterior Abdominal Wall—Psoas Major (Magnus)— 'igin. —(1) The inner part of the anterior surface of the transverse ocesses of the lumbar vertebrae; (2) the lateral aspects of the inter

842

A MANUAL OF ANATOMY

vertebral discs, and of the adjacent borders of the twelfth thorac and all the lumbar vertebrae; and (3) a series of fibrous arches whi cross the lumbar vessels at the centres of the bodies of the lumb vertebrae.

Insertion .—The lesser trochanter of the femur, by a tendon whi receives on its outer side the greater part of the iliacus.

Nerve-supply .—The lumbar plexus. The branches come me particularly from the anterior primary divisions of the second ai third lumbar nerves.

Action .—Acting from its origin, the muscle is a powerful flexor the thigh upon the pelvis, coming into play in walking, or ascendi a stair; it is a weak medial rotator of the hip. Acting from its i sertion, it is a flexor of the lumbar portion of the vertebral colun upon the pelvis, and of the pelvis upon the thigh, as in the act of stoo ing. The muscle of one side, acting from its insertion, is capable producing lateral flexion of the lumbar portion of the vertebral colum

As the muscle descends close to the pelvic brim the fibres of t iliacus begin to join the outer side of its tendon, and they contin to do so as far as the insertion, thus giving rise to a conjoined mus( known as the ilio-psoas.

Psoas Minor (Parvus). —This muscle is present in man on one or both sic in about 45 per cent, of bodies. It arises from the lateral aspect of the inti vertebral disc between the twelfth thoracic and first lumbar vertebrae, and fre the contiguous borders of their bodies, by means of a small fleshy belly, which usually about 2 inches long. It is then replaced by a long, narrow, flat tendc which expands as it is about to take insertion into the middle of the pectin* line and the ilio-pubic eminence, in which latter situation it blends with the il pectineal intermuscular septum. It also gives an aponeurotic expansion to t whole length of the inguinal ligament.

The nerve-supply is the anterior primary division of the first lumbar nen Acting from its origin, the muscle tends to flex the pelvis upon the vertebi column, and is a tensor of the psoas sheath. Acting from its insertion, it ten to flex the lumbar portion and lower part of the thoracic portion of the vertebi column upon the pelvis. Its characteristic action is seen in the position assum by saltatory animals preparatory to the act of leaping, that position consisti in a drawing forwards of the pelvis and vertebral column.

The psoas minor lies along the anterior aspect of the psoas major close to inner border, except at the pelvic brim, where its expanded tendon turns to t inner side of that muscle.

Iliacus — Origin. — (1) The lateral part of the upper surface of the a of the sacrum; (2) the anterior sacro-iliac, ilio-lumbar, and lumb sacral ligaments; and (3) the upper half of the iliac fossa, reachii anteriorly as low as the anterior inferior iliac spine.

Insertion. —(1) The outer aspect of the tendon of the psoas majo (2) the triangular surface which is situated below, and in front c the lesser trochanter of the femur (between it and the spiral line and (3) the ilio-femoral ligament. The fibres inserted into the ili femoral ligament are those which arise in the region of the anterior i ferior iliac spine. They are sometimes separated from the rest of tj muscle, and are then known as the ilio-capsularis.

THE ABDOMEN

843

Nerve-supply .—The femoral nerve.

Action .—Acting from its origin, the muscle is a flexor of the thigh pon the pelvis. Acting from its insertion, it is a flexor of the pelvis pon the thigh.

Quadratus Lumborum — Origin. —(1) The ilio-lumbar ligament;

) the inner lip of the crest of the ilium for about 2 inches behind

id outside the ilio-lumbar ligament; and (3) the tips of the transverse rocesses of the lower three or four lumbar vertebrae.

Insertion. — (1) The lower border of the last rib along its inner half, id (2) the tips of the transverse processes of the upper three or four

Obturator Externus

Fig. 487.—The Psoas, Iliacus, and Quadratus Lumborum Muscles.

imbar vertebrae, by tendinous slips which lie behind the slips of origin, he fibres of the muscle are so arranged as to form deep and supernal layers; the deep layer consists of ilio-transverse fibres, the supercial layer of transverso-costal fibres medianly and of ilio-costal fibres derally.

. Nerve-supply .—The subcostal nerve and the anterior primary l visions of the first two lumbar nerves.

Action .-—Acting from its origin, the muscle depresses and fixes le . last rib, and is therefore a muscle of inspiration, inasmuch as ls auxiliary to the diaphragm. In depressing the last rib the

844 A MANUAL OF ANATOMY

muscle is also capable of producing lateral flexion of the vertebi column. Acting from the last rib, it will produce lateral flexion the pelvis.

The muscle is encased in a sheath, the anterior wall of which formed by the anterior layer of the lumbar fascia, and the posteri wall by the middle layer.

Lumbar Plexus. —The lumbar plexus is situated deeply in front the transverse processes of the first three lumbar vertebrae in the su stance of the psoas major. It is formed by the anterior prima divisions of the first three lumbar nerves and the greater part of th

of the fourth. In addition, ti anterior primary division of the fir lumbar is usually reinforced by small communicating branch fro the subcostal nerve, called the dors lumbar nerve. The nerves concern! in the lumbar plexus first furnish tl following branches: (i) the first giv twigs to the psoas minor when pre ent; (2) the first and second supp branches to the quadratus lur borum; (3) the second and thii give branches to the psoas majo and (4) the upper two or three fu nish white rami communicantes 1 the lumbar sympathetic gangliate trunk. The mode of formation ar branches of the plexus are as follow the first lumbar, having been, as rule, reinforced by the dorso-lumb; from the subcostal, furnishes, froi above downwards, the ilio-hyp< gastric and ilio-inguinal, and the it descends to join a branch from tl second. The second, third, and th; part of the fourth which enters ini the plexus break up into a sma anterior or ventral, and a large po: terior or dorsal division. The descending branch from the first joir a branch from the ventral division of the second to form th genito-femoral nerve, which arises next in order to the ilio-inguina The lateral cutaneous nerve of thigh arises by two roots from th dorsal divisions of the second and third. The femoral nerve arise by three roots from the dorsal divisions of the second, third, an fourth, the root from the third being the largest. The obturator nerv arises usually by three roots from the ventral divisions of the seconc third, and fourth, but the root from the second may be absent. Thj accessory obturator nerve, when present, arises by two roots from th

Fig. 488. —Diagram of the Right Lumbar Plexus.

THE ABDOMEN 845

ird and fourth, which are interposed between the roots of the femoral id main obturator nerves.

The branches of the lumbar plexus are accordingly as follows:

1. Muscular to psoas minor (when present), from first lumbar.

2. Muscular to quadratus lumborum, from first and second lumbar.

3. Muscular to psoas major, from second and third lumbar.

4. Two or three white rami communicantes, to the lumbar sympaetic gangliated trunk, from the upper two or three lumbar.

5. Ilio-hypogastric and ilio-inguinal, from first lumbar.

6. Genito-femoral, from first and ventral division of second lumbar.

7. Lateral cutaneous nerve of thigh, from dorsal divisions of second Ld third lumbar.

8. Femoral, from dorsal divisions of second, third, and fourth mbar.

9. Obturator, from ventral divisions of second, third, and fourth mbar.

10. Accessory obturator (when present), from third and fourth mbar, between the roots of the femoral and main obturator.

The ilio-hypogastric nerve, having pierced the outer border of the oas major near its upper part, passes outwards and downwards over e quadratus lumborum, lying below the subcostal nerve and behind e kidney. It then pierces the posterior part of the transversus >dominis a little above the iliac crest, and furnishes its lateral cutaneous anch, which, perforating the internal and external oblique, crosses e iliac crest at the junction of its middle and anterior thirds to be stributed to the integument of the adjacent part of the gluteal region, le nerve continues its course forwards between the internal oblique id transversus abdominis, supplying branches to these muscles and mmunicating with the ilio-inguinal nerve.' About 1 inch in front of e anterior .superior iliac spine it pierces the internal oblique, and then ns forwards between the fibres of that muscle which arise from the guinal ligament and the external oblique aponeurosis. Finally, it erces that aponeurosis 1 inch above the superficial inguinal ring, and distributed to the integument of the suprapubic region, where it is

series with the anterior cutaneous nerves. The ilio-hypogastric irve is serially continuous with the intercostal nerves; like these it ves off a lateral cutaneous branch, and then ends as an anterior itaneous nerve.

The ilio-inguinal nerve, having pierced the outer border of the psoas ajor lower down than, but close to, the ilio-hypogastric, passes diquely outwards and downwards over the quadratus lumborum, here it may lie below the lower end of the kidney or behind it. It en passes forwards immediately above the inner lip of the iliac crest meath the transversus abdominis. In this part of its course it may I st upon the iliac fascia and iliacus muscle. Near the anterior part the iliac crest it pierces the transversus, and here communicates with e anterior cutaneous branch of the ilio-hypogastric. It subsequently rforates the internal oblique, after which it descends through the

A MANUAL OF ANATOMY

846

lower two-thirds of the inguinal canal, and emerges through the sup ficial inguinal ring, where it lies lateral to the spermatic cord. Fina] having pierced the external spermatic fascia, it is distributed to ' integument of the inner side of the thigh in its upper third, and integument of the scrotum or labium majus, according to the s The ilio-inguinal nerve in its course supplies branches to the inter oblique and transversus abdominis muscles. It differs from the f hypogastric and intercostal nerves in the following two respects: it d< not give off any lateral cutaneous branch, and it is not distribui to the skin of the abdominal wall. The ilio-hypogastric and ilio-ingui nerves often arise by a common trunk, and their fibres for a considera part of their course are often contained in the same sheath.

The genito-femoral nerve (genito-crural nerve) passes forwa: through the psoas major, and appears on its superficial surface ab( the level of the body of the third lumbar vertebrae, where it lies close the inner border of the muscle. It sometimes pierces the muscle two parts, due to an early division of the nerve into its genital a femoral branches. It then descends upon the psoas sheath, passi slightly outwards, and crossing behind the ureter. At a variable c tance above the inguinal ligament (sometimes in the psoas major) 1 nerve divides into two branches, genital and femoral. The gem branch lies upon the external iliac artery close above the inguinal lij ment, and enters the inguinal canal through the deep inguinal n to be distributed to the cremaster muscle. The femoral branch descer on the outer side of the external iliac artery, and passes out behi the inguinal ligament, having just prior to this crossed the deep circu flex iliac artery. On entering the thigh it lies for about J inch wit] the femoral sheath, and subsequently, piercing the outer wall of tl sheath, is distributed to the skin over the femoral triangle.

The lateral cutaneous nerve of thigh pierces the outer border of 1 psoas major near its centre, and takes a direction downwards and 0 wards over the back part of the iliac crest into the iliac fossa. It tl crosses the iliacus under cover of the fascia iliaca towards the anter superior iliac spine, where it enters the thigh behind the outer end the inguinal ligament. For the distribution of the nerve in the thij see p. 564.

The femoral nerve (anterior crural nerve) pierces the outer bon of the psoas major about the level of the back part of the pelvic bri It then passes forwards, lying deeply between the psoas major a iliacus, and appears in the thigh behind the inguinal ligament. Whi in the abdominal cavity it gives branches to the iliacus muscle. I course and distribution of the nerve in the thigh will be found

P- 575 The obturator nerve pierces the inner border of the psoas maj at the back part of the pelvic brim, and lies upon the ala of the sacru having the lumbo-sacral trunk deep to it on its inner side. Passi deeply behind the common iliac artery it enters the pelvic cavity, ai passes along the outer wall a little below the pelvic brim, where it 1

THE ABDOMEN

>

847

ove the obturator artery. -It then enters the thigh through the turator canal. For the course and distribution of the nerve in the [gh, see p. 579.

The accessory obturator nerve (when present) pierces the inner border of the >as major close to the main obturator nerve, but, unlike it, does not enter the vie cavity. Its course is forwards along the inner border of the psoas major derneath the external iliac vessels, and it emerges on to the thigh by passing sr the superior pubic ramus beneath the pectineus muscle. Under cover of it muscle it divides into the following three branches: articular to the hipnt; muscular to the deep surface of the pectineus; and a reinforcing branch join the superficial or anterior division of the main obturator nerve. It is netimes very small and only represented by articular branches. At its origin s more closely associated with the femoral nerve than with the main obturator, is present in about 30 per cent, of cases.

Varieties of the Lumbar Plexus. —These assume the form of two types, high prefixed, and low or postfixed. In the prefixed type the anterior primary dsion of the third lumbar is a nervus furcalis, and takes part in the sacral

xus; whilst in the postfixed type the anterior primary division of the fifth

nbar is a nervus furcalis, and takes part in the lumbar plexus.

Lumbo-sacral Trunk. —This is formed by the union of the ventral d dorsal divisions of the descending branch of the fourth lumbar

rve with the ventral and dorsal divisions of the anterior primary

vision of the fifth lumbar. It is a large double trunk, which rests >on the ala of the sacrum, being at first under cover of the psoas ajor, and subsequently lying on its inner side, where it has the •turator nerve lateral and superficial to it. In its course it passes hind the common and internal iliac vessels, and in the pelvis, its two visions having joined those of the anterior primary division of the st sacral nerve, it takes part in the sacral plexus, entering more .rticularly the upper or outer band of that^plexus which is continued to the sciatic nerve.

The anterior primary division of the fourth lumbar nerve is known a nervus furcalis from the fact that it is distributed partly to the mbar and partly to the sacral plexus.

Lumbar Arteries. —These are branches of the abdominal aorta, mg parietal in their distribution, and serially continuous with the •sterior intercostal and subcostal arteries. They are eight in number, ur right and four left, and they arise in pairs, separately or conjointly, )m the posterior aspect of the parent trunk. They occupy the grooves the centres of the bodies of the first four lumbar vertebrae. As each tery winds round a vertebral body it passes beneath one of the fibrous ches of the psoas major and the lumbar sympathetic gangliated ^mk. It then passes behind the psoas major and lumbar plexus, and L reaching the interval between two adjacent lumbar transverse prosses it gives off a posterior branch. The upper two arteries pass neath the corresponding crus of the diaphragm, and those of the (ht side also pass beneath the cisterna chyli and the azygos vein.

1 four arteries on the right side pass beneath the inferior vena cava. le trunk of each lumbar artery gives off a few vertebra, branches to e body and ligaments of the adjacent vertebral and muscular branches

848

A MANUAL OF ANATOMY

to the psoas major. The posterior branch passes backwards betv the adjacent transverse processes in company with the posh primary division of a spinal nerve, and divides into a medial and lat branch. The medial branch supplies the multifidus, and the lat branch supplies the sacro-spinalis, giving also cutaneous branches w. accompany the cutaneous nerves to the skin. Opposite an ir vertebral foramen the dorsal branch furnishes a spinal branch , wi enters the vertebral canal through the foramen, to be distributee the spinal cord and its coverings, as well as to the wall of the cana

The continuations of the arteries then usually pass behind quadratus lumborum, with the exception, as a rule, of that of the fou At the outer border of that muscle they pierce the aponeurosis of transversus abdominis, and pass forwards between that muscle and internal oblique as far as the lower part of the rectus abdominis, w] they enter. They furnish the following offsets: muscular to the qr ratus lumborum; extraperitoneal to the extraperitoneal arei tissue, which anastomoses with branches of the ilio-lumbar, thephre and the hepatic colic, and renal arteries, thus forming the ex peritoneal arterial plexus of Turner; muscular to the abdonr muscles, which anastomose above with the lower two intercostal ; subcostal arteries, below with the ascending branch of the deep circi flex iliac and ilio-lumbar, and in front with the inferior epigast Sometimes there are five lumbar arteries on each side, the fifth ] coming usually from the median sacral artery. Each of these pa: beneath the corresponding common iliac vessels, and having furnis' a lumbar branch, usually to the gluteus maximus, is distributed o the lateral mass of the sacrum, and ends in the iliacus, where it ar tomoses with the deep circumflex iliac artery.

The lumbar veins open into the inferior vena cava, those of left side passing behind the abdominal aorta. The vessels of e; side are connected by a series of longitudinal anastomosing veins front of the lumbar transverse processes, and the longitudinal ve: thus formed is called the ascending lumbar vein.

Subcostal Artery. —This vessel is the last parietal branch of thoracic aorta. It lies below the last rib, and is in series with posterior intercostals above and the lumbar arteries below. It wii round the side of the body of the twelfth thoracic vertebra, and coui along the lower border of the twelfth rib with the subcostal ner passing behind the lateral arcuate ligament of the diaphragm and front of the quadratus lumborum. This part of the vessel is beh: the kidney and the ascending or descending colon according to the si Its subsequent course corresponds with that of the lumbar arteries, anastomoses with the lower two intercostal arteries, the termi branches of the lumbar arteries, the ascending branch of the d< circumflex iliac, and the inferior epigastric artery. This vessel has be borne in mind in such operations as nephrotomy, nephrorrhap] and nephrectomy.

The subcostal vein of each side enters the thorax behind the late'

i

THE ABDOMEN 849

uate ligament of the diaphragm, the right opening into the azygos

n, and the left into the inferior vena hemiazygos.

Subcostal Nerve. —This is the anterior primary division of the elfth thoracic nerve, and is in series with the eleventh or last internal. It accompanies the subcostal artery, and ultimately enters J sheath of the rectus abdominis, which muscle it pierces from behind wards to become an anterior cutaneous nerve. In its course it gives an undivided lateral cutaneous branchy which pierces the internal 1 external oblique muscles, and descends ir the iliac crest to be distributed to the n of the anterior part of the gluteal

ion; this branch may be small or absent,

sides this branch it furnishes the follow; offsets: (x) dorso-lumbar to the anterior mary division of the first lumbar nerve;

I (2) branches to the quadratus lumborum, nsversus abdominis, internal oblique, and ramidalis.

Lumbar Glands. —These are very numer>, and are divided into four groups—

!-aortic, retro-aortic, and juxta-aortic, ht and left. They lie behind the parietal 'itoneum, in front of, behind, and along J sides of the aorta and inferior vena cava, e lower glands are continuous with the per members of the group of the common .c glands. The lumbar glands receive iir afferent vessels from the following irees: (1) the alimentary canal down to

anal orifice; (2) the liver and gall-bladder;'

the pancreas; (4) the spleen; (5) the testes the male; the ovaries, uterine tubes, and per end of the uterus in the female; the kidneys; (7) the suprarenal glands; the vertebral part of the diaphragm; the common iliac glands; and (10) the iominal wall. Their efferent vessels unite form the lymphatic intestinal and the nphatic lumbar trunks, which in turn

n to form the cisterna chyli at the level of the body of the second nbar vertebra.

Common Iliac Arteries. —These vessels are the terminal branches of i abdominal aorta. They arise from that vessel opposite the centre the body of the fourth lumbar vertebra, a finger’s breadth to the t of the middle line, and they at once diverge from each other. Their irse is obliquely downwards and outwards over the lower portion the body of the fourth and the whole of that of the fifth lumbar -tebra, as well as the disc between the two. Each artery, on arriving

54

Fig. 488A.— Scheme illustrating the ‘ Groups ’ of Aortic Glands (modified FROM RoUVIERE).

Glands in front of aorta are pre-aortic, PA; those beside aorta are right and left lateral aortic, RL, LL ; the right lateral group is composed of sub-groups: A-V, between

• aorta and vena cava inferior ; PV, prevenous; RV, retro-venous ; and LV, latero-venous. Glands behind the aorta are not shown, being made up of derivatives from one or both lateral groups.

8 5 o

A MANUAL OF ANATOMY

opposite the lumbo-sacral articulation, ends by dividing into exter and internal iliac arteries. The length of the right common iliac about 2 inches, and that of the left about if inches. The left ve< is less oblique in direction than the right, and the course of each may indicated in the following manner: draw a line from a point £ ir below the umbilicus, a finger’s breadth to the left of the middle li to a point at the groin midway between the anterior superior iliac sp and the symphysis pubis, and let this line be slightly curved with 1 convexity directed outwards. About the upper 2 inches of this 1: indicate the course of the common iliac artery, and the remainder tl of the external iliac vessel.

Inferior Vena Cava

Aorta Suprarenal Lymphatics

Renal Lymphatics

Right Common Iliac Glands

Right External Iliac Glands

- Median Group of Lumbar Glands

Lymphatics ol Left Testis

-r- Sacral Glands

Right Internal Iliac Glands

Fig. 489.—Lymphatics of the Abdomen (after Mascagni).

Relations Anterior. The peritoneum, coils of the small intestin one halt of the aortic sympathetic plexus, and the ureter, which lath crosses the artery close to its termination, though it may be transferre o e commencement of the external iliac vessel. An additional supei hcial relation of the left common iliac artery is that it is crossed by tb superior rectal vessels.

Posterior.— Each artery rests upon the lower half of the body c

e +L OU ^- W ^°^ e that of the fifth lumbar vertebra, as we

as the disc above and below the latter, and the gangliated sympatheti trunk, the right vessel is separated from the foregoing structures b;

te commencement of the inferior vena cava, the terminal part of th lett common iliac vein, and the right common iliac vein, whilst the lei

THE ABDOMEN

851

'essel is free from posterior venous relations. Lying deeply behind ach artery there are the obturator nerve, lumbo-sacral trunk, and >etween them the ilio-lumbar artery.

External. —On the outer side of the right vessel there are, from hove downwards, the inferior vena cava, right common iliac vein, nd psoas major. On the outer side of the left vessel is the psoas najor.

Internal. —On the inner side of the right vessel, from below upwards, there are the right common iliac vein, the left common iliac rein, and the hypogastric sympathetic plexus. On the inner side of he left vessel there are the left common iliac vein and the hypogastric )lexus.

Pelvic Colon Greater Omentum

1 ig . 490. — Transverse Section at the Level of the Disc between the Body of the Fifth Lumbar Vertebra and the Sacrum (after Symington).

_ It is to be noted that the left artery is related only to its own r ein, which lies on its inner side. The right artery, on the other [and, is related to three veins as follows: the inferior vena cava, which ies partly behind its upper end and partly on its outer side; the terminal >art of the left common iliac vein, which lies partly on its inner side nd partly behind it; and the right common iliac vein, which, from >elow upwards, lies first on its inner side, then behind it, and finally >n its outer side.

The inner, outer, and middle chains of common iliac glands lie on he inner, outer, and posterior aspects respectively of the common liac vessels.

Branches. —These are as follows: peritoneal to the peritoneum md extraperitoneal areolar tissue; muscular to the psoas major;

852

A MANUAL OF ANATOMY

ureteric to the ureter (all of small size and unimportant); exter iliac; and internal iliac. In some cases the common iliac gives one or other of the folJpwing vessels: ilio-lumbar, median sacral, late sacral, lumbar, or an aberrant renal artery.

Varieties. —The chief variety affects the length of the vessel. It may very short, which is due either to a low bifurcation of the aorta or a high bifui tion of the artery itself; or it may be very long, which is due to exactly oppo causes. When abnormally long, the vessel is usually more or less tortuous.

Collateral Circulation. —After ligature of a common iliac artery, the cl channels by which the circulation is carried on are as follows: (1) the supe: epigastric of the internal mammary from the first part of the subclavian ana: moses with the inferior epigastric of the external iliac; (2) the lumbar branc of the aorta anastomose with (a) the ascending branch of the deep circumj iliac from the external iliac, and ( b) the ilio-lumbar of the internal iliac; (3) superior rectal of the inferior mesenteric from the aorta anastomoses with (a) middle rectal of the internal iliac, and (b) the inferior rectal of the inter pudendal from the internal iliac; (4) the median sacral from the aorta anastomc with the lateral sacral branches of the internal iliac; and (5) the pubic branc' of the obturator from the internal iliac and of the inferior epigastric from external iliac, both of one side, anastomose across the middle line with the coi sponding branches of the opposite side. The vesical and middle and inferior rec arteries of one side anastomose in a similar manner with those of the oppo: side.

Common Iliac Veins. —Each vein is formed by the union of t external and internal iliac veins opposite the corresponding sac] iliac articulation on a level with the brim of the pelvis. They un to form the inferior vena cava opposite the upper border of the bo of the fifth lumbar vertebra a little to the right of the middle lb behind and on the right side of the right common iliac artery. T right vein is necessarily shorter than the left, and it ascends almc vertically, lying at first medial to, then behind, and finally on t outer side of its own artery. The left vein ascends very oblique from left to right, lying medial to its own artery, and then behind tb of th right side. It crosses the median sacral artery, and is cross by the superior rectal vessels and the left half of the aortic plexi The common iliac veins are usually destitute of valves.

Tributaries. —These are chiefly the external iliac, internal ilia and ilio-lumbar. In addition, the left vein receives the median sacr vein.

Ihe left common iliac vein is mainly the persistent and enlarged transve1 branch (transverse iliac) which connects the right and left supracardinal periganglionic veins of the embryo above the back part of the pelvic brim. I commencement, however, is developed from the left veins. The right comrn< iliac vein is developed from the part of the right cardinal vein which interven between the termination of the right external iliac vein and the right extremi of the transverse iliac vein.

Common Iliac Lymphatic Glands. —These glands are about m

in number, and are arranged in three groups —lateral, intermediate, ai medial—which lie along the common iliac artery. The afferent vesse of the lateral and intermediate groups are derived from the external ai internal iliac glands; the afferent vessels of the medial group procee

THE ABDOMEN

853

1 the other hand, directly from the viscera, from (1) the prostate and, (2) the base of the bladder, (3) the lower part of the vagina, and ) the cervix uteri.

The efferent vessels of all the common iliac glands of one side pass the juxta-aortic glands of the same side.

External Iliac Artery.—This vessel is the larger of the two terminal visions of the common iliac in the adult. It extends from the lumbocral articulation to the lower margin of the inguinal ligament, where is continued into the femoral artery. Its course is along the pelvic im, and at the groin it passes through the vascular lacuna at a point idway between the anterior superior iliac spine and the symphysis

Pelvic Colon Bladder

l /

G - 49i- —Transverse Section at the Level of the Second Sacral Vertebra

(after Symington).

ibis. The course of the vessel may be indicated in the following anner: draw a line from a point f inch below the umbilicus; a finger’s 'eadth to the left of the middle line, to a point at the groin midway 'tween the anterior superior iliac spine and the symphysis pubis, and t this line be slightly curved with the convexity directed outwards, bout the upper 2 inches of this line indicate the course of the common ac artery, and the remainder that of the external iliac vessel. The le indicating the course of the vessel corresponds to the lower part of tat which has been given as indicating the course of the common iliac, be vessel is from 3J to 4 inches long, and its direction is downwards, itwards, and forwards.

§54

A MANUAL OF ANATOMY

Relations —A nterior .—The artery is covered by the parietal p toneum aild extraperitoneal areolar tissue, the portion of the la which is related to it being known as Abernethy’s fascia. The ri vessel at its commencement is crossed by the terminal part of ileum, and sometimes by the vermiform appendix, whilst the left its commencement is crossed by the pelvic colon, and each may crossed by the ureter. In the female both arteries are crossed superic by the ovarian vessels. Near the inguinal ligament each vesse crossed by the deep circumflex iliac vein, and the genital branch of genito-femoral nerve lies upon it. The testicular vessels in the rr also lie for a short distance upon it in this situation, and the vas defer for ligamentum teres of the uterus) arches over it from without inwai The external iliac glands lie along the artery. Posterior .—The art rests upon the iliac fascia at the pelvic brim, except for a little ab the inguinal ligament, where it lies upon the psoas muscle with intervention of the fascia which forms its sheath. The right art at its commencement has its own vein behind it for a short distance, c each vessel may have the accessory obturator nerve as a deep poste] relation. Lateral .—The psoas major covered by the iliac fascia, genito-femoral nerve, and its femoral branch. Internal .—The p< toneum, the extraperitoneal areolar tissue (Abernethy’s fascia), wh binds the artery with its vein to the iliac fascia, the external iliac v (except for a short distance above on the right side, where the veir behind the artery), and the vas deferens near the inguinal ligamen

Branches.—These are as follows: muscular to the psoas maj glandular to the external iliac glands (both unimportant); infer epigastric; and deep circumflex iliac. For the latter two, see pp. ' and 732.

Varieties of the Branches. —(1) The origin of the inferior epigastric maytransferred to the femoral, or to the arteria profunda femoris, and the dc circumflex iliac may be transferred to the femoral. (2) The medial circumfl obturator, or arteria profunda femoris may arise from the external iliac, in wh latter case two large arteries would emerge on to the thigh beneath the ingui ligament.

The external iliac vein is the continuation of the femoral vein, extends from the lower border of the inguinal ligament to the sac iliac articulation on a level with the brim of the pelvis, where it jo: the internal iliac, and so forms the common iliac vein. The right v< lies at first medial to its artery, and then behind it. The left vein 1 medial to its artery throughout. Its chief tributaries are the infer epigastric and deep circumflex iliac veins.

The external iliac vein of adult life is preceded in function by the infer] gluteal vein of the embryo, which is the primitive vein of the lower limb. In i process of development the upper part of the femoral and the whole of 1 external iliac vein of the adult are continued upwards from the long saphenc vein to the cardinal portion of each common iliac vein, and the inferior glut* vein is now a tributary of the internal iliac.

Collateral Circulation. —When the external iliac artery is ligatured, tj collateral circulation is carried on through the following channels: (1) t

t

i.

THE ABDOMEN

855

iperior epigastric of the internal mammary from the first part of the subclavian nastomoses with the inferior epigastric of the external iliac; (2) the pubic ranch of the obturator from the internal iliac anastomoses with the pubic ranch of the inferior epigastric; (3) the ilio-lumbar and superior gluteal, both om the internal iliac, and the abdominal branches of the lumbar arteries from le aorta anastomose with the deep circumflex iliac of the external iliac; (4) the Dturator from the internal iliac anastomoses with the medial circumflex of the •teria profunda femoris; (5) the inferior gluteal from the internal iliac anas>moses with the medial and lateral circumflex, and the first perforating of the •teria profunda femoris; (6) the gluteal anastomoses with the external circum3X and the ascending branch of the medial circumflex from the arteria pronda femoris; (7) the companion artery of sciatic nerve of the inferior gluteal lastomoses with the perforating branches of the arteria profunda femoris; and ) the superficial perineal and dorsal artery of penis of the internal pudendal from ie internal iliac anastomose with the superficial and deep external pudendal of le femoral.

External Iliac Lymphatic Glands.—These glands are related to the eternal iliac vessels, and are about twelve in number. They are usually rranged in three chains —lateral, intermediate, and medial—there eing about four glands in each chain. The lateral chain lies on the der side of the external iliac artery, between it and the psoas major tuscle, except the lowest gland, which lies upon that muscle. The iter mediate chain lies in front of the interval between the external iac artery and vein. The medial chain lies below the level of the exjrnal iliac vein, upon the upper part of the lateral wall of the pelvis, bove the obturator nerve. One of the glands of this chain may lie ithin the pelvic entrance to the- obturator canal, and is spoken of 5 the obturator gland, but it is not constant. The lowest gland of ich chain lies close to the deep aspect of the inguinal ligament, and lese are known as the retro-femoral glands—* lateral, intermediate, and ledial respectively.

The afferent vessels of the external iliac glands convey lymph from tie following sources:

1. The deep inguinal glands.

2. Some of the superficial inguinal glands.

3. The deep structures of the antero-lateral abdominal wall below tie umbilicus.

4* To a certain extent the glans penis or glans clitoridis, these unphatics passing along the inguinal canal.

5. The adductor muscles.

6. The prostate gland and prostatic urethra in part.

7- The bladder.

8. Part of the membranous and the bulbar portions of the urethra.

9- The upper part of the vagina.

10. The body and cervix of the uterus.

The efferent vessels of all the external iliac glands pass to the ommon iliac glands.

Lacunar Region.—The lacunar region is situated between the Jguinal ligament and the anterior margin of the hip bone, and is ivided into two compartments—muscular and vascular.

8 5 6

A MANUAL OF ANATOMY

The muscular lacuna is subdivided into two portions, lateral iliac, and medial or pectineal, by the ilio-pectineal septum , wl separates the psoas magnus from the pectineus. This septum pa; between the ilio-pubic eminence and the fascia iliaca at its poini junction with the upper part of the pubic portion of the fascia 1; The lateral compartment, which is of large size, is bounded in front the outer part of the inguinal ligament and the iliac fascia, behind the anterior margin of the ilium, and medially by the ilio-pectir septum. It transmits (i) the ilio-psoas muscle, (2) the lateral cutane nerve of thigh, and (3) the femoral nerve. The medial compartmen situated between the superior pubic ramus behind and the upper p of the pubic lamina of the fascia lata in front, the ilio-pectineal sept being lateral tout. It contains the origin of the pectineus muscle, £ is shut off from the abdominal cavity by the attachment of the pn lamina of the fascia lata to the medial portion of the pectineal line, connection with this portion of the fascia lata there is a bundle fibres, known as the pectineal ligament [of Cooper ). This ligam extends between the ilio-pubic eminence and the pubic tubercle, tween which points it is attached to the medial portion of the pectir line in front of the pectineal part of inguinal ligament, being clos incorporated with the pubic lamina of the fascia lata.

The vascular lacuna is situated anterior to the other two. Il bounded posteriorly by the connection between the iliac fascia £ the pubic lamina of the fascia lata, whilst anteriorly it is bounded the central portion of the inguinal ligament and the downward p longation of the fascia transversalis to form the anterior wall of femoral sheath, that fascia being here strengthened by the deep feme arch. It gives passage to (1) the external iliac vessels, the vein be medial to the artery; and (2) the femoral branch of the genito-femo nerve, which lies close to the outer side of the artery. The part of t lacuna medial to the external iliac vein forms the femoral ring, wh is closed by the femoral septum.

STRUCTURE AND DEVELOPMENT OF THE ABDOMINAL

VISCERA.

Structure of the Stomach.

The wall of the stomach is composed of four coats—serous, mi cular, submucous, and mucous.

The serous coat is formed by the peritoneum, which covers eve part of the organ except (1) along the lesser and greater curvatur and (2) the uncovered trigone, situated on the posterior surface, bel( and a little to the left of the cardiac orifice.

The muscular coat (muscularsi externa) is composed of plain muscui tissue disposed in three layers—external or longitudinal, middle circular, and internal or oblique. The external or longitudinal fib) are continuous with the longitudinal fibres of the oesophagus, and

THE ABDOMEN

CEsophagus

857

pyloric end of the stomach they are continuous with the longitudinal

• es of the duodenum. They are most abundant along the lesser

vature, and partially separate off in that region a tubular portion the cavity known as the intergastric canal, which is thought provide for the rapid trans;sion of fluids. The middle or ular fibres completely surround stomach from the fundus to pyloric end. At first they are 1 and irregular in position, Longitudniaijiuscuiar-j

over the pyloric canal they thick. At the pylorus they ome augmented, and are gathi together into a thick muscular l, called the pyloric sphincter, ich lies within a circular fold the mucous membrane. The ermost fibres of this ring bele continuous with the circular es of the duodenum. Some of circular fibres appear to be itinuous with the superficial 'ular fibres of the right side of the lower end of the oesophagus.

3 internal or oblique fibres are continuous with the circular fibres of

the left side of the lower end of the oesophagus. They loop over the stomach immediately to the left of the cardiac orifice, and run very obliquely downwards and to the right for a considerable distance on both surfaces of the organ. They cannot be traced as far as the pylorus, but end by inclining downwards to the greater curvature, where they blend with the circular fibres.

The submucous coat situated between the

Pyloric Sphincter

Fig. 492. — Dissection showing the Muscular Layers of the Stomach.

Cardiac Orifice

CEsophagus

Fundus

sser Curvature

mmon tic Duct

Stic Duct

Pylorus

■ile Duct '

--Greater

Curvature

-Pancreatic Duct

Duodenum

493.—The Stomach and Duodenum opened.

is

muscular and mucous coats. It is composed of areolar tissue, and serves partly as a connecting medium, and % as a bed in which the arteries subdivide before entering the cous coat.

8 5 8

A MANUAL OF ANATOMY

The mucous coat is covered by a single layer of columnar epithe It is soft and pulpy, and in the empty state of the viscus is th into folds, which are for the most part longitudinal, and are due t loose connection between the muscular and mucous coats. T however, are readily effaced when the stomach becomes distei It is thickest towards the pyloric end, and in healthy adults it ] light crimson colour, while in early life this is heightened into a b rosy tint. After death, however, it presents a mottled appear being marked with grey-brown patches. When examined with a it presents a great number of polygonal depressions, varying in diar from T Jo to -lo inch, the largest being near the pylorus. These in

to it a honeycomb appear

Duct

Mucosa with Cardiac Glands

Muscularis Mucosae

Submucosa

) Muscular Coat

The mucous membrane surrc ing them is elevated into r by subjacent capillary netw and in the region of the py these ridges present proc( called plicce villosce. The gonal depressions are beset minute pores, which are the hces of the gastric glands. 1 glands, which belong to the tui variety, are placed perpen larly in the mucous coat, are closely packed together upright stakes. They are of kinds, cardiac and pyloric, tween which there are ce differences.

The cardiac glands are siti the cardiac two-thirds.

in

Peritoneal Coat

duct of each forms about oneof the entire length of the g It is lined with a single lay

Fig. 494.—The Cardiac Glands of

'A, 1 , A. L AO AAAA^VJ. VV i- LAA CL OAAA£;A^ ACL

the Stomach (highly magnified). columnar epithelium. The

end of the duct is connected with two or three gland-tubes, 1 represent two-thirds of the entire gland. Each gland-tube is dfv into a neck, body, and fundus. The neck is the part connected the duct, and it forms one-third of the length of the gland-tub( is narrower than the body, and is lined with coarsely granular polyt cells, which almost completely fill it, thus leaving a very small li These are called the central or chief cells. Between these am basement membrane there are interposed large oval or sph granular cells, each having a clear nucleus. These, which are < the parietal or oxyntic (‘ acid-forming ’) cells, do not form a contii layer, but are placed at intervals, and they give rise to small swe on the wall of the neck. The body is wider than the neck, and i two-thirds of the length of the gland-tube. It is lined by a prolong

THE ABDOMEN

Mucosa with Pyloric Glands

Muscularis Mucosae

859

he central or chief cells of the neck, which almost completely fill it, which have now become somewhat columnar and transparent, ween these cells and the basement membrane there are a few ietal or oxyntic cells here and

e. The parietal cells of the

k and body impart the characstic beaded appearance to the id-tube. The fundus is the d deep end of the gland-tube.

The pyloric glands are situated he pyloric third. The duct of 1 forms one-half of the entire (th of the gland. It is lined 1 a single layer of columnar helium. The deep end of the t is connected with two or re gland-tubes, which represent -half of the entire gland. The k of each tube is comparatively rt, and the body is branched ts deep extremity. The neck body are lined with cubical mlar cells, representing the tral or chief cells of the cardiac ids, and they are not so vded as in the cardiac glands,

Tat there is a very distinct en. There is an entire absence of parietal or oxyntic cells, and body of each gland-tube has an undulating, convoluted outline.

pyloric glands are serially continuous with Brunner’s glands of

small intestine.

} Submucosa

K Muscular Coat

Peritoneal Coat

Fig. 495.— The Pyloric Glands of the Stomach (highly magnified).

Summary of the Cardiac and Pyloric Glands.

Cardiac Glands.

)ucts short.

hand-tubes long.

hand-tubes almost filled with coarsely granular polyhedral cells, called central or chief cells.

arnien very small.

dand-tubes have parietal or oxyntic cells between the central cells and the basement membrane.

Pyloric Glands.

1. Ducts long.

2. Gland-tubes short.

3. Gland-tubes lined with cubical

granular cells.

4. Lumen distinct.

5. Gland-tubes destitute of parietal

or oxyntic cells.

At the deepest part of the mucous coat, and forming a part of ii re is a stratum of plain muscular tissue, called the muscularis mucos> 'scularis interna), which is disposed in two layers—outer longitudim ^ inner circular. The mucous membrane is also provided wit l phoid tissue in the interspaces between the deep ends of the gastri

86 o

A MANUAL OF ANATOMY

glands. In the cardiac part of the stomach this lymphoid tissue oci in the form of isolated collections, called lymph follicles, which be; resemblance to the solitary glands of the intestinal mucous membr; In the neighbourhood of the pylorus these lymph follicles bec< aggregated, and so resemble somewhat the aggregated lymph nodules of the small intestine.

Blood-supply—Arteries.—Along the lesser curvature there

(1) the left gastric branch of the coeliac artery in two divisions,

(2) the right gastric branch of the hepatic, also in two divisions. A 1 the greater curvature there are (1) the right gastro-epiploic of gastro-duodenal of the hepatic from the coeliac artery, and (2) the gastro-epiploic of the splenic from the coeliac artery. At the fur there are the short gastrics of the splenic artery.

The branches arising from all these arteries enter the muscular < without piercing the peritoneum. They subsequently make t way inwards to the submucous coat, where they break up into bram which freely anastomose with one another. Fine branches then e] the mucous coat, which run upwards between the closely-packed gas glands, round which they form by their anastomoses a delicate capil] network with its meshes elongated in the direction of the gland-tu From their network somewhat larger vessels proceed upwards, wl by their anastomoses form a coarser and more superficial netw around the orifices of the ducts of the glands. The arteries along lesser curvature are smaller, longer, and not so tortuous as those al the greater curvature; further, they do not anastomose so fre features which are probably attributable to the fact that the le curvature, unlike the greater curvature, undergoes relatively li change in distension of the stomach.

Veins.—These arise from the superficial network of capilla round the orifices of the ducts of the glands. They take a downw course between the gland-tubes, and on reaching their deep ends t form a plexus. From this plexus branches proceed outwards to submucous coat, in which they form another plexus. The branc arising from this latter plexus, having passed through the musci coat, terminate in the following veins: (1) the right gastro-epipl which opens into the superior mesenteric; (2) the left gastro-epiploic ■ short gastrics, which open into the splenic; (3) the left gastric; < (4) the prepyloric, the latter two opening directly into the portal v The veins of the stomach contain numerous valves, which are si ciently competent in early life to oppose the return of venous blc but in the adult they are incompetent.

Lymphatics.—These commence near the free surface of the muc membrane either in loups or in enlargements, and they take a do ward course between the gland-tubes, where they open into a 1 work of lacunar spaces. The branches which proceed from ' network, on reaching the deep ends of the glands, form a ple> and the vessels issuing from this plexus, on entering the submuc coat, form another plexus, the lymphatics of which are furnished v

86i

THE ABDOMEN

yes. The vessels which emerge from this latter plexus accompany bloodvessels, and pass to the lesser and greater curvatures, and vicinity of the hilum of the spleen. At the lesser curvature y are connected with the coronary glands, at the greater curvature i the subpyloric glands,

1 st those which accomy the short gastric

ries pass through the

nic glands, the efferent >els of all these glands mately passing to the iac glands. In addition the lymphatic vessels described there is a peritoneal lymphatic

[US.

Nerves.—These are ded from (i) the two i nerves, and (2) symletic plexuses from the

ac plexus. The right

us nerve descends upon Fig - 49 5 A -— Scheme (after Rouviere) of the .posterior surface of the Chains of Lymph Glands accompanying the nach, whilst the left r Ranches of the Celiac Artery (CA)

ve descends upon the V * £ T. 1 •? 7 l"

rinr wvfnr? cT/rrr Also shows the lymphatic territories of the stomach

v jace. ine sym- corresponding with the vascular supplies. ietic plexuses closely

)mpany the arteries. The nerves form two gangliated plexuses posed of non-medullated nerve-fibres. One of these is situated veen the longitudinal and circular fibres of the external muscular and corresponds to the plexus myentericus of Auerbach of the stine. The other plexus is situated in the submucous coat, and esponds to the plexus of Meissner of the intestine.

■ he explanation of the right vagus nerve descending upon the posterior tee, and the left upon the anterior surface, of the stomach is found in the

ion assumed by the stomach in the early embryo. Briefly stated, at that

)d of life the stomach is a straight tube, and its surfaces are right and left, two vagi nerves, therefore, right and left, naturally descend on the right left surfaces of the viscus. When, however, the stomach turns over on its owing to the enlargement of the omental bursa towards the left, the surface h was originally right becomes posterior, and the surface which was originally becomes anterior. Thus the right nerve eventually descends on the posterior mally the right) surface, and the left nerve descends on the anterior (originally eft) surface.

Pylorus.—The opening between the pyloric end of the stomach the duodenum is provided with a sphincter muscle, called the nc sphincter. This is formed by an aggregation of the circular cular fibres, which causes the mucous membrane to project in form of an annular fold, thus giving rise to the pyloric valve. The

862

A MANUAL OF ANATOMY

pyloric sphincter is only relaxed when the contents of the sto are being passed into the duodenum. At all other times it is condition of firm contraction, and the pyloric orifice then take form of a cleft.

The average length of the stomach is about io inches, and its average at the widest part about 5 inches. Its capacity is very variable.

Development of the Stomach (for general relations, etc., of the early stc see p. 79).—The cavity of the stomach begins to show a dilatation befoi 5 mm. stage. The dilatation increases fairly rapidly, possibly in assoc with the freedom ensured by the fact that the organ is carried on the wall of the lesser sac; the area of the fundus is quite distinct before the e the first month as an enlargement to the left of the line of the wall of the 1 which is only connected with the body and pyloric portion. The fundus not begin to grow out to its proper size, however, before the end of the s month.

Fig. 496.—Three Sections in Region of Stomach at Differeni

Developmental Stages.

The first shows the condition of the wall at 10 mm. The second show nature of the pits in the lining layer during the third month. The section illustrates the sudden changes seen in the disposition of the 1 membrane, etc., in passing from the pyloric region (P) to the duodenuir

The lining layer of the stomach is fairly thick, and is embedded in a mesodermal coat. In the fifth week (Fig. 496) a faint indication of the civ muscular coat can be seen on the right side of the viscus (left in figure) lining epithelium shows several tiers of cells where cut obliquely, but prob as in the lower part of the section, there are really some three or four layers the middle of the second month the circular coat is more or less complete, some indications of the other coats are to be found. The lining layer, beco thinner as the stomach grows, shows irregularities on its free surface, espec in the pyloric portion. The organ is now very vascular. During the 1 month the surface irregularities of the epithelium, now a single cell layer, definite short pits (Fig. 496), which are not—at any rate at first—mad folding of the layer as a whole, but by inequalities in height of its cells mesoderm grows in later between the pits. This pitting of the epithe appears to be more marked in the pyloric region. The pit-like appearan

due to section; they are really of the nature of cleft-like sinkings in the sin layer.

In the fifth month and subsequently glands are formed as secondary growths of the floors of these pits, starting apparently from certain eosino

THE ABDOMEN

863

>, which constitute altogether or in part the floors. These eosinopile cells [i to be the direct precursors of the parietal cells of the cardiac glands, rhe cavity of the stomach presents certain folds or grooves which appear >e fairly constant. Among these are two grooves which run longitudinally ig the lines, more or less, of the two curvatures, and two folds project into cavity on either side of the future lesser curvature. These folds enclose the - of the ‘ internal gastric canal/ which is thus almost as well marked in the >ryo of the second month as in many adult bodies. These folds and grooves lot pass into the pyloric part.

rhe pyloric portion of the stomach is, in the embryo, a contracted, tube-like il, much longer compared with the rest of the organ than in the adult. It )t, however, to be looked on as part of the duodenum, from which it may be mguished very early (Fig. 496).

Structure of the Intestinal Canal.

Small Intestine. The wall of the small intestine, which is cylin al, is composed of four coats—serous, muscular, submucous, and

ous.

The serous coat is formed by peritoneum derived from the mesenT P ro per. In the case of the duodenum it is incomplete, but it ns a complete investment to the jejunum and ileum, except along irrow interval corresponding to the mesenteric border of the bowel, re the peritoneal investment becomes continuous with the two

rs of the mesentery proper.

rhe muscular coat (muscularis externa) is composed of plain musr tissue, disposed in two layers, external or longitudinal, .land rnal or circular.. The external or longitudinal fibres are continuous 1 the corresponding fibres of the stomach, and they are best marked tg the anti-mesenteric border. The internal or circular fibres are tmuous with the outermost fibres of the sphincter pylori, and form uch thicker layer than the longitudinal. The muscular coat attains greatest thickness in the duodenum, whence it gradually diminishes, ween the two muscular layers there is a gangliated plexus of nonaillated nerve-fibres, called the myenteric plexus (Auerbach’s plexus), also a plexus of lymphatic vessels.

Hie submucous coat is situated between the muscular and mucous s. It is composed of loose areolar tissue, and serves partly as a lectmg medium and partly as a bed in which the arteries subtle. It contains a gangliated plexus of non-medullated nerve^s, called the plexus of the submucosa (Meissner’s plexus), and a “Us of lymphatic vessels. In the duodenum this coat lodges the denal glands, and the deep ends of the solitary nodules project it throughout. ^ J

rhe mucous coat is red and thick in the upper part of the small stme, but pale and thin in the lower part. It is covered by a e layer of columnar epithelium. The protoplasm of the cells is Itudmally fibrillated. Underneath the epithelium there is a baseb ^ m .k rane > known as the subefiithelial endothelium , and underf s * s main part of the mucous coat, which is essentially corn'd of adenoid tissue—that is to say, retiform tissue containing in

864 A MANUAL OF ANATOMY

its meshes lymph corpuscles. At the deepest part of the mucous and forming a part of it, there is a stratum of plain muscular ti called the muscularis mucosce (muscularis interna ), which in i situations is disposed in two layers—outer longitudinal and circular. In some places, however, only the outer longitudinal is present. The mucous coat is beset all over with minute projecl called villi, and is sometimes called the villous coat. These impart to it a woolly appearance like the nap of velvet. It dimm in thickness from above downwards, and is characterized by the folic structures: (i) circular folds, (2) villi, (3) duodenal glands, (4) intes glands, (5) lymphoid nodules, and (6) aggregated lymphoid nodule Of the foregoing structures the circular folds, villi, and aggre^ nodules constitute the macroscopical (naked-eye) characters ol mucous membrane, the others forming its microscopical character The circular folds (valvulae conniventes) are permanent folds 0 mucous membrane which cannot be effaced. They are absent

the first part of the duodenum for a disl of from 1 to 2 inches from the pylorus. ( mencing about the upper end of the second of the duodenum as small straggling folds, become large and distinct at the place oj trance of the bile-duct and pancreatic (about 4 inches from the pylorus). Throug the rest of the duodenum and in the upper of the jejunum they are still prominent, am placed close to each other. In the lower of the jejunum they become smaller, and placed farther apart. In the upper part oi ileum they become still smaller and more gular, and they finally disappear just be] the centre of the ileum. They are cresc( folds placed across the bowel, and each con of two layers of mucous membrane applied 1 to back, with a little submucous areolar ti Fig. 497. —The Circu- intervening. Their average length is a lar Folds. 2J inches, and the average breadth of eac

about J inch. The majority of them ex round the bowel for from one-half to two-thirds of its circumfere Some, however, describe complete circles, whilst a few are arrai in a spiral manner so as to describe from one to three turns round tube. Some of them begin and terminate in bifurcated extremi whilst others present abrupt single extremities. The purpose sei by the circular folds is a twofold one. In the first place they incr the extent of the absorbing and secreting surface of the mucous m brane, and in the second place they delay the passage of the intest contents, and so afford time for digestion and absorption.

In connection with the circular folds of the duodenum the com] orifice of the bile-duct and pancreatic duct has to be noted. At

1

THE ABDOMEN

865

ction of the inner and posterior aspects of the second part of the )denum, where the upper two-thirds and lower third of that part st, there is a small eminence of the mucous membrane, called the

idenal papilla. It lies at the

er end of a vertically-placed 1 , which bifurcates so as to form ind of hood for it. From the er part of the papilla a fold ends downwards for some disce, which acts as a bridle, and es the apex a downward direc1. On the summit of this papilla re is an opening which reprets the common orifice of the > ducts. These ducts, having versed the wall of the second t of the duodenum obliquely f inch, unite to form one duct, ch, before piercing the mucous t, presents an enlargement

Fig. 498.— Duodenal Papilla. A, papilla; B, circular folds.

Goblet Cell

ed the ampulla, but subsequently narrows at its final ending. In ampulla a gallstone may become lodged and delayed in its down'd progress toward the duodenum. About 1 inch above the duodenal papilla there is another small papilla upon which there is another minute opening. This represents the orifice of the accessory pancreatic duel.

The villi commence at the beginning of the duodenum on the outer side of the pylorus, and extend as far as the margins of the segments of the ileo-colic valve. They are minute projections of the mucous membrane, to which they impart a velvety appearance, and may be visible to the naked eye, but are more readify seen with the aid of an ordinary lens if a portion of bowel is floated in water. They are closely set upon the mucous

Fig. 499.—Two Villi.

villus, Showing striated basilar are C K l0SeI y Set "P 0 * the mucous )r der, columnar epithelium, goblet membrane (circular folds included),

hmp -- epithelium, goblet v ils, and lacteal vessel; B, villus, except over the solitary glands, mowing the capillary bloodvessels. Their total number is said to be

about four millions (Krause). The are conical, cylindrical, leaf-like or finger-like processes, varying ^ngth from To to To inch. They are larger and more numerous e lower part of the duodenum and in the jejunum, especially at

55

866 A MANUAL OF ANATOMY

its upper part, than in the ileum, and they diminish both in size number from above downwards, becoming somewhat filiform in ileum. Each villus is an elevation of the mucous membrane coverec a single layer of columnar epithelium. It is composed of (i) adei tissue, (2) a capillary network of bloodvessels, (3) one or more lac vessels ensheathed by plain muscular tissue, and (4) arborization nerve-fibrils derived from the plexus of the submucosa.

Between the columnar epithelial cells of the free surface there amoeboid lymph corpuscles. Beneath the epithelium is a basen membrane composed of flattened cells, and known as the subepith endothelium. The cells of this basement membrane send procc between the columnar cells of the free surface, and also are conne< with the branched cells of the retiform tissue of the adenoid tis One artery (sometimes two) enters the base of the villus and asc( to near the centre. Here it breaks up into a number of branc which form a copious capillary network. From this plexus the bi is returned by one or two venous radicles, which leave the villu its base, where they open into the venous plexus of the mucous m brane. In the centre of the villus there is a lacteal vessel, which c mences near the tip in a blind bulbous extremity, or if there shoul<

two lacteals, they originate in the fom a loop. The wall of the lacteal vess( formed by a single layer of endothelial pk which are connected by processes with branched cells of the retiform tissue of adenoid tissue. The vessel is ensheathec longitudinal plain muscular fibres der; from the muscularis mucosae, their fi cells being connected with the basen membrane of the villus. The villus is vaded by adenoid tissue—that is to retiform tissue with its meshes filled a amoeboid lymph corpuscles. The branc cells of this retiform tissue are connectec processes, on the one hand, with the er thelial plates which compose the wall of lacteal vessel, and on the other hand ^ the cells of the basement membrane near surface, and these latter in turn send processes between the columnar epith cells of the free surface.

The villi play a most important par absorption, partly through their cop capillary networks, and partly through t lacteals. The lacteals serve specially for absorption of fats, which is probably effected in the following man the columnar epithelial cells at the free surface take up the sapon) and emulsified fats, which they transfer to the amoeboid lymph )

Duodenal Glands

Fig. 500.—Section of the Duodenum, showing Duodenal Glands (highly magnified).

THE ABDOMEN

867

iscles between them. These corpuscles then carry the fats inwards rough the adenoid tissue into the lacteal vessel.

Duodenal glands (Brunner’s glands) are confined to the duodenum, id are serially continuous with the pyloric glands of the stomach, ley are very numerous in the commencement of the duodenum, iere they form a continuous layer of gland tissue extending as low the entrance of the bile-duct and pancreatic duct. Beyond this ant they gradually diminish in number, and ultimately disappear ar the duodeno-jejunal flexure. They belong to the class of race3 se or acmo-tubular glands,, and they differ from the pyloric glands the stomach in having their tubules more branched and in having

Villus ____

Intestinal Gland

Solitary Nodule Muscularis Mucosas

Submucosa

Circular Muscular Fibres

>ngitudinal Muscular Fibres

Peritoneal Coat __=§§§=

’Mucosa

Fig. 501. —Vertical Transverse Section of the Small Intestine

(highly magnified).

iger ducts. Otherwise the structure of the two kinds of glands is nlar. The duodenal glands lie embedded in the submucous coat, i their long ducts pass through the whole thickness of the mucous d, upon the surface of which they open between the intestinal glands, tte of them, however, open into these glands. The glands can easily displayed by removing the peritoneal and muscular coats of the ^denum and a little of the submucous areolar tissue, when they ^ear as small, round, grey-coloured masses like millet seeds, varying diameter from T V to inch.

the intestinal glands (crypts of Lieberkiihn) are found in large fibers over the whole of the mucous membrane of the small intestine, well as that of the large bowel. They belong to the class of simple

868

A MANUAL OF ANATOMY

tubular glands, and are to be regarded as small diverticula of tl mucous membrane. Each gland takes the form of a simple tub which is closed and slightly enlarged at its deep extremity, and opei by its other end on the surface between the villi. The glands a] present on the circular folds as well as in the intervening parts. The are placed vertically and close together, and are confined entirely to tf mucous coat, in which they extend from the free surface to the musci laris mucosae. In length they vary from ^ to yTq inch. Each glan is composed of a basement membrane lined with columnar epitheliun and the lumen is of large size.

The solitary nodules are present over the whole extent of the mucoi membrane of the small intestine. They assume the form of small, whit round, or oval nodules, which project by their deep ends into the sul mucous coat, whilst their superficial ends give rise to slight elevatior of the free surface, where they have the openings of the intestin; glands placed around them. They are found upon, as well as betweei the circular folds. In structure each solitary nodule is composed ( adenoid tissue containing large numbers of lymph corpuscles, and pe: meated by capillary networks. Each nodule is surrounded at its dee part by a copious plexus of lymphatic vessels, or by lymphatic sinuse The solitary nodules are simply lymphoid tissue.

The aggregated nodules (Peyer’s patches) are peculiar to the sma intestine, and average about thirty in number in the adult, bein

more numerous in early life. They are situate along the free or anti-mesenteric border of th bowel, which must therefore be opened alon its attached or mesenteric border in order t preserve them. They are largest, best market and most plentiful in the lower half of the ileun In the upper part of the ileum and lower pai of the jejunum they become smaller and mor scarce, and they disappear as a rule above th centre of the jejunum. They vary in lengt from inch to 4 inches, their breadth rangin from J inch to 1 inch. They are for the mos part oblong, their long axis coinciding with tha of the bowel. In the upper part of the ileui and lower part of the jejunum, however, the are somewhat circular. Each aggregated nodul is composed of a group of solitary lymphoi nodules, surrounded by lymphatic plexuses c lymphatic sinuses. The area of each aggregate nodule is slightly elevated, and there are no vil over the lymphoid nodules, whilst the opening of the intestinal glands are arranged in

Fig. 502.—An Aggregated Lymphoid Nodule.

circular manner round each nodule. There are no circular folds ove the aggregated nodules. The aggregated nodules are best marke in young persons. Towards middle life they fade away, and in ol

THE ABDOMEN 869

persons they are usually only distinguishable as discoloured portions of the mucous membrane.

Blood-supply—Arteries.—The duodenum receives its arteries from the superior pancreatico-duodenal of the gastro-duodenal from the hepatic, and the inferior pancreatico-duodenal of the superior mesenteric. The jejunum receives its arteries from the jejunal branches of the superior mesenteric. The ileum receives its arteries from the ileal arteries, and its terminal part in addition receives its arterial supply from the ileal branch of the ileo-colic from the superior mesenteric.

Veins.—The destination of the venous blood of the small intestine is the superior mesenteric vein, and thereafter the portal vein. The veins are provided with valves which are competent in early life, but in the adult they are incompetent, and therefore allow regurgitation of blood to take place towards the small intestine, as happens in cases of portal obstruction.

Lymphatics.—These form a copious plexus of valved vessels, which is situated in the submucous coat. This plexus receives the lymphatics of the mucous membrane and the lacteals of the villi, and it surrounds the deep ends of the solitary nodules. Its efferent vessels pierce the muscular coat, and in doing so they take up the lymph from an intramuscular plexus of lymphatics, which lies between the longitudinal and circular layers. They then leave the bowel at the mesenteric border, where they pass between the two layers of the mesentery, and on their way to the cisterna chyli they traverse the superior mesenteric glands.

Nerves.—These are derived from the superior mesenteric sympathetic plexus, and they form two gangliated plexuses of nonmedullated nerve-fibres. One of these is situated in the muscular coat between the longitudinal and circular layers, and is known as the myenteric plexus (Auerbach’s plexus) (plexus of the muscular coat of the intestine). The other is situated in the submucous coat, and is called the plexus of the submucosa (Meissner’s plexus). The branches of this latter plexus are distributed to the muscularis mucosae and the mucous membrane with its villi.

Characters of Different Parts of the Small Intestine—Duodenum — Peritoneum. —There is no mesentery and only a partial investment of peritoneum. Muscular coat. —This is very thick. Submucous Coat.- —-This contains the tubular portions of the duodenal glands. Mucous Coat .—The characters of this coat are as follows: (1) circular folds, except in the first 1 or 2 inches, (2) villi, (3) intestinal glands, (4) solitary nodules, (5) ducts of the duodenal glands, (6) common orifice of the bile-duct and pancreatic duct, and (7) orifice of the accessory pancreatic duct.

The diameter of the duodenum is from 1^ to 2 inches.

Jejunum — Peritoneum. —There is a mesentery, and the bowel is surrounded by peritoneum except along its mesenteric border. Muscular Coat .—This is comparatively thin. Mucous Coat .—This has the following characters: (1) circular folds, (2) villi in abundance, (3) intestinal glands, (4) solitary nodules, and (5) aggregated lymphoid nodules in its lower half.

The diameter of the jejunum is about i-| inches.

Ileum — Peritoneum. —In this respect the ileum resembles the jejunum.

870

A MANUAL OF ANATOMY

Muscular Coat. —This is very thin. Mucous Coat. —The characters of this co, are as follows: (1) circular folds in upper half, but small and sparse, there beii none in the lower half; (2) villi, but in fewer numbers; (3) intestinal gland (4) solitary nodules; and (5) aggregated lymphoid nodules.

The diameter of the ileum is about 1^ inches.

Development of Small Intestine. —The epithelial lining is at first like th

of the stomach, and the muscular coat develops also in a similar way. Vacuol appear in the epithelium, leading in the duodenum to subdivision of the lume but not in the rest of the gut, where, however, they may produce pouches. Vi appear in the upper part first, about the seventh week, and are found throughoi the gut in the fourth month. They may form by the breaking up of longitudin ridges, or may form separately. Glands develop as simple pits between villi the fourth month, first in the upper gut. They tend to branch later. T, duodenal glands seem to be formed from the simple forms by lateral branchii and growth in length during the fourth month. They are not fully formed ; birth, however.

Large Intestine.—The wall of the large intestine, which is sacculate* is composed of four coats—serous, muscular, submucous, and mucou

The serous coat forms a complete investment to the vermifori appendix, caecum, transverse colon, and pelvic colon. As regarc the ascending colon and descending colon, it is incomplete, being absei behind.

The muscular coat (muscularis externa) is composed of plain muscuk tissue disposed in two layers—external or longitudinal, and internal ( circular.

The longitudinal muscular fibres are for the most part collected ini three flat bands, called taeniae coli, except upon the rectum. In tl intervals between these bands there are some longitudinal fibres, but the are very few and scattered. The taeniae, which are about J inch i breadth, commence upon the caecum at the base of the vermiform a] pendix, and they extend along the several parts of the large intestir as far as the rectum, where they spread out and form a continuot covering, which completely surrounds that part of the bowel. Upc the caecum, ascending colon, descending colon, and iliac colon the teni from their disposition are called anterior, postero-internal, and poster* external. Upon the transverse colon they are so placed as to be calle anterior or omental (greater omentum), postero-inferior or free, an superior or meso-colic (transverse meso-colon). They are shorter tha the bowel to which they are applied, with the result that the tube drawn together or puckered, and thus thrown into sacculi. Thei being three taeniae, there are three rows of sacculi between them, an inasmuch as the taeniae are placed at nearly equal distances from eac other, the sacculi are pretty much of equal dimensions. Between th successive sacculi there are constrictions, usually containing fat. Th sacculi give rise internally to large pouches, and the constrictior between the sacculi produce internally sharp crescentic rugae, whic separate the pouches from each other. When the taeniae are divide*: the sacculi and constrictions entirely disappear, and the large bow* becomes elongated into a smooth cylindrical tube. Along the cours of the taeniae there are a number of small processes of peritoneum cor

THE ABDOMEN

871

ining fat, called appendices epiploicae. They are best marked on the ansverse colon and on the upper part of the pelvic colon, and are least arked, as a rule, on the caecum. Except in the case of the transverse )lon, these are chiefly found along the postero-internal taenia, but in le case of the transverse colon they are principally met with along the Dstero-inferior taenia.

The circular fibres are thin and scattered over the sacculi, but in le constrictions between them they become aggregated. Upon the ctum and anal canal they form a thick layer, which in the latter tuation is known as the sphincter ani internus.

The submucous coat is in all respects similar to that of the small Ltestine.

The mucous coat is pale and greyish in colour, except in the rectum, here it is red. Its epithelium is similar to that of the small intestine.

is destitute of circular folds and villi, and consequently presents a

nooth surface. It contains large numbers of intestinal glands, which iound in mucus-secreting goblet cells. It also contains solitary anphoid nodules, which are especially prevalent in the vermiform ppendix and caecum. The deepest part of the mucous coat is formed y the musculans mucosce ( muscularis interna).

Blood-supply—Arteries.—These are as follows: (1) appendicular, >r the vermiform appendix; (2) anterior and posterior caecal, for the mim; (3) colic of ileo-colic and right colic, for the ascending colon; |.) middle colic, for the transverse colon (all branches of the superior lesenteric); (5) left colic, for the descending colon; and (6) sigmoid rteries, for the iliac colon and pelvic colon (the latter two being branches f the inferior mesenteric).

Veins.—The destination of the venous blood of the vermiform ppendix, caecum, ascending colon, and transverse colon is the superior lesenteric vein, whilst the blood of the descending colon, iliac colon, nd pelvic colon is carried into the inferior mesenteric vein. In both ases the further destination of the blood is the vena portae. As in the mall intestine, the veins have valves which are competent in early life, ut not so in the adult.

The lymphatics will be found described on pp. 799 and 802.

Nerves.—These are derived from the superior mesenteric sympathetic plexus and the inferior mesenteric plexus, which latter is an ffshoot from the aortic plexus. The disposition of the nerves correponds with that in the small intestine.

The large intestine diminishes gradually in size from its commencement to its termination. Its diameter varies in different parts, the xtremes being 2\ inches and 1 inch.

Characters of the Large Intestine — Peritoneal Coat. —This presents at frequent ntervals small projections called appendices epiploicae. Muscular Coat. —The ongitudinal fibres are for the most part arranged in three taeniae. Mucous "oat. —This is destitute of ( a ) circular folds, (b) villi, (c) duodenal glands, and d ) aggregated nodules, but it is provided with (1) intestinal glands, and (2) solitary lodules. Outline of Tube. —The bowel presents three rows of sacculi, except in -he vermiform appendix and rectum.

872

A MANUAL OF ANATOMY

Development. —There is nothing remarkable about the epithelial grow which resembles that of the small gut. The lumen is at first very small and walls thick. The bowel begins to enlarge about the time of its entrance ii the belly, but even then is much smaller than the small intestine. Villi deve' in it during the fourth month, but become smaller and less distinct during succeeding months. Glands form between the villi, but the details of their forr tion are not known with certainty. Villi are found in the vermiform appea in the fourth month, with gland formation.

Structure of the Vermiform Appendix.—The vermiform appenc is entirely covered by peritoneum, which forms a more or less compk

Solitary Nodules

Fig. 503.—Transverse Section of the Vermiform Appendix

(magnified).

meso-appendix or appendicular mesentery. It has a muscular coa composed of an external longitudinal and internal circular layer, both < which completely surround it. The submucous coat contains in gre; abundance solitary nodules of large size, and the mucous coat contaii a few solitary nodules, as well as a few intestinal glands. The base < the appendix is situated at a point on an average rather more tha 1 inch below the ileo-colic valve, according to Treves. The openir by which the appendix communicates with the caecum is occasional guarded by a fold of mucous membrane, which is known as the ileo-coll valve (valve of Gerlach).

THE ABDOMEN

873

The vermiform appendix is usually regarded as the remains of the herbivorous aecum. It is also looked upon as an appendage of the lymphoid system, and as ich it would belong to the class of structures represented by aggregated nodules -namely, lymphoid organs.

Ileo-colic Valve (Valve of Tulpius).—This valve is situated at the oint where the terminal part of the ileum opens into the junction etween the caecum and ascending colon. The orifice, as seen from the iterior of the large intestine, has the form of a slightly oblique cleft bout J inch long, and running in an antero-posterior direction. It is ounded above and below by the two segments which form the valve, nd which project into the large intestine. The upper or ileo-colic egment is prominent, and occupies an almost horizontal plane. The

Dwer or ileo-ccecal segment, longer than the upper, is concave superiorly, nd occupies an oblique plane. The anterior part of the cleft is rounded h, whilst the posterior part tapers to a point. The segments meet in ront of and behind the cleft, and form two prominent folds, which are >rolonged round the wall of the bowel for some distance. These folds re known as the frenula. Each segment is composed of two layers »f mucous membrane, one of which belongs to the ileum, and the other 0 the caecum or colon, as the case may be. These two layers are coninuous with each other at the free margin of the segment, and they ontain between them submucous areolar tissue and circular muscular Tres, both of which are derived partly from the ileum and partly from he large intestine. The longitudinal muscular fibres and the serous or >eritoneal coat take no part in the formation of the segments, being

874

A MANUAL OF ANATOMY

continued uninterruptedly from the ileum to the large intestine. ' mucous membrane which covers the opposed surfaces of the segrm belongs to the ileum, and is therefore provided with villi. The muc membrane of the other surfaces—that is to say, the surfaces which I away from each other (downwards and upwards respectively)—be! to the caecum and colon, and are destitute of villi. The villi thus < appear at the margins of the segments. The valve may be descril as being formed by an inversion of the terminal part of the ileum i the large intestine. That part of the ileum, having passed upwa and to the right with a slight inclination backwards, enters the la intestine. As it does so it leaves behind its serous and longitudi muscular coats, and takes with it its circular muscular, submucc and mucous coats, the corresponding coats of the large intest accompanying it in the inversion. The ileo-colic valve prevents regurgitation of the contents of the caecum into the ileum. It generally believed that the mode of action of the valve is as folio 1 when the caecum becomes distended the frenula of the valve are stretcl and exercise traction upon its segments, which are thereby brou| together. The valve is usually represented in figures as it appears wl the caecum has been inflated and dried. In the fresh condition segments of the valve are thick and tumid, and the appearance is ] unlike that of the pyloric valve as seen from the duodenum or of cervix uteri as seen from the vagina; the frenula, again, are much 1 apparent in such a caecum.

For the structure of the rectum, see p. 960.

Development of Positions of the Stomach and Intestinal Canal.

This subject is dealt with shortly on pp. 61-65 and 79-81. These pa should be studied before reading what follows.

Dorsally, the roof of the mid-gut is at first close to the notochord, but, growth goes on, it comes away from this close relationship, drawing out mesoderm between them as it does so, to form the dorsal mesentery, the man in which this change is effected is not quite clear.

At an early stage, therefore, the alimentary tube in the abdomen can described as being short, median in position, extending from the septum tra versum to the cloaca, and, between these limits, making a short curve, com ventrally, and suspended by a median dorsal mesentery. The vitelline duct attached to it at the lowest part of its curve, and as development proceeds 1 intestinal loop lengthens, so that this lowest part of it passes out of the abdon into the ‘ umbilical sac.’ The elongation of the loop implies a correspond! lengthening of the dorsal mesentery opposite it (see Fig. 44).

Stomach. —This is a dilatation of that part of the tube which is resting the septum transversum. Its attachment here lengthens and thins as the li 1 grows in the septum, and at the same time its dorsal mesentery (meso-gastriu is pouched out to the left, carrying the stomach with it, and turning it so tl its left surface becomes somewhat ventral. The pouch of dorsal meso-gastrii is known as the omental bursa.

Intestinal Canal. —This canal is at first very short and almost straight, aij gs has been stated, it communicates freely with the yolk-sac. At this sh there is no indication of a division into small and large intestine. When wide opening leading to the yolk-sac becomes constricted and converted i: the vitelline duct, the intestinal canal undergoes lengthening, and a conspicu'

THE ABDOMEN

8 75

) is formed, which projects into the cavity of the proximal part of the umbilical i, this cavity being a direct prolongation of the coelom or body-cavity. This ) is spoken of as the U-loop. The convexity of the bend of the loop is directed ! ralwards, and the vitelline duct is connected with the convexity. The loop two limbs, which lie at first parallel to each other. One limb is cephalic, >er, or proximal, and leads from the duodenal loop of the gut; the other limb audal, lower, or distal, and leads to the caudal end of the gut. Upon the al limb a bud makes its appearance. This assumes the form of a blind diverlum, or cul-de-sac, which is the rudiment of the ceecum. The appearance of caecal evagination is the first indication of the division of the intestinal canal > small and large intestine. The primitive small intestine is the part on the

Fig. 5 ° 5 - —The U-Loop, 8 mm., just projecting into the Umbilical Sac. Left and right views. Vitelline duct cut Short.

)ximal side of the rudimentary cascum, and the primitive large intestine is the ft extending from the rudimentary caecum to the caudal end of the gut.

The portion of mesentery which is drawn out as the proper mesentery of the loop contains the superior mesenteric artery between its layers. The artery originally continued on beyond the loop as the vitelline artery, but this soon appears and leaves its trunk as the superior mesenteric.

As the stomach lies in the front wall of the rudimentary lesser sac (bursa lentalis), its pyloric end is directed towards the right, and the very short piece the tube which comes next, the future duodenum, lies rather to the right of the ddle line, and is attached to the median common dorsal mesentery by a thick so-duodenum, which projects on that side of it, just below the opening of the ser sac.

8y6

A MANUAL OF ANATOMY

The intestinal tract is thus seen to consist of intra- and extra-abdorr portions, part of the colon being in the abdomen, and the anterior limb of loop being connected with the duodenum by an intra-abdominal duod umbilical loop of gut.

These different parts of the intestinal tract can be seen in Fig. 505, in w the conditions in a 8 mm. embryo simplified are shown from both sides; the lobe of the liver has been cut away to expose the mesentery and gut, for it cc down at this stage on the left side of the bursa omentalis and mesentery a: as the right lobe on the other side. The neck of the umbilical loop of gut p< out between the two lobes of the liver in a deep notch in the ventral edge oJ

Fig. 506.—Left-sided Views of Umbilical Loop at 9 mm. (Above) and 10 1

(Lower Figure).

organ. An angled bend is seen where the hind-gut is continuous with the hin limb of the loop; this is produced by the attachment here to the gut of a retent band in the mesentery, extending from the peri-aortic region in the neighbourhc of the cceliac artery. The angle must not be mistaken for the left colic flexu with which it has nothing to do; it is gradually effaced as development procee and its ultimate position, if it persisted, would be some little distance to 1 left of the mid-point of the transverse colon.

With the exception of the short length of the duodeno-umbilical piece, wh becomes the first coil of the jejunum, the small intestine is formed in the umbili sac, as are those parts of the large gut which become the ascending and right k of the transverse colon. Formed in this sac, the gut enters the abdomen a

THE ABDOMEN

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ain stage, and within this cavity is finally disposed in its proper situations.

processes that lead to the ‘ rotation ’ of the intestine can thus be divided

descriptive purposes into three stages—the development outside the belly, entrance into the abdomen and the immediate mechanical results of this nge, and the subsequent assumption of the definitive positions.

Fig. 507.—Two Diagrams to show Earlier Stages of Gut and Mesentery within the Belly and in the Umbilical Sac.

First Stage. —The general disposition in the earlier part of this stage can be a in Fig. 507, A and B. It is marked by the fairly rapid growth in length of anterior or proximal limb of the umbilical loop, forming coils. The ruditttary lesser sac enlarges, passing down on the left side of the median abdominal sentery, between it and the liver. Two or three points in connection with the

1. 508.—Schemes of the Umbilical Loop showing the Sort of Growthchanges THAT OCCUR WITHIN IT (SEE TEXT).

ngating proximal limb must be noted, as they are concerned with the subseent entry and disposal of the gut within the belly cavity: in the first place, ' proximal limb lies, from an early stage on the right side * of the loop, as can

• The immediate cause of this is not certain. It may be due to the position

the stomach, making the duodenum pass towards the right, or it may be iociated with the development of the vitello-umbilical anastomosis, which 3 in the concavity of this part of the limb of the loop, but any definite state"nt on the subject would be unwarranted.

A MANUAL OF ANATOMY

878

be seen in the figures; secondly, the growth of the proximal limb is associated w marked increase in the depth of the corresponding mesentery of the loop, that the distance between the coils of this limb and the superior mesente artery is much increased; the hinder limb of the loop does not grow like 1 proximal limb, and its distance from the artery remains unchanged, whence comes about that the artery gets relatively nearer and nearer to the hinder lii of the loop. At the back of the loop, where it is passing through the open: in the abdominal wall, the artery is still approximately midway between the t limbs, and it is only distal to this that the unequal growth of the constituent pa of the mesentery of the loop leads to the one-sided position of the vessel.

Fig. 509 illustrates the appearance at the end of the first stage. The cseci is now a large dilatation with a conical extremity, placed on the left side of • mass of coils of small intestine. The mesentery of the small gut is long, and 1 superior mesenteric artery is close to the colon and caecum. The bursa omenh really extends caudally along the whole extent of the left side of the int abdominal colon and meso-colon, separating these from the left lobe of the liv in the figure, however, it is shown as somewhat pushed up, to allow the med: colon and meso-colon to be seen. At the end of this stage, then, the intesti: coils are on the right of the caecum and colon in the umbilical sac, the super mesenteric artery is close to the colon and far from the coils, and the bu omentalis is on the left of a ‘ median abdominal septum ’ made of abdominal coi and meso-colon.

Second Stage. —The recession of the umbilical gut within the belly is brou^ about by a fall in ‘ intra-abdominal tension ' resulting from lessened growth-r of the liver. This organ fills all the available space in the abdomen during 1 second month, growing pari passu with the surrounding parts, but in the ea part of the third month its rate of growth falls behind that of these parts. T does not at first affect the mass in the umbilical sac, and is met by increase in 1 amount of blood in the liver vessels, which are consequently dilated. In 1 tenth week, however, approaching the 40 mm. stage, this dilatation of lr vessels may be considered to have reached its maximum, and any further incre; in the capacity of the abdomen calls for the appearance of some additional si stance to fill the space which otherwise must come into being. The umbili coils are alone able to fulfil this role, and the extra-abdominal or amniotic pressi not being lessened by the fall in the growth-rate of the liver, the contents of 1 umbilical sac are pushed by it into the abdomen to compensate for the inter: fall. It is to be noted now that as the coils enter the abdomen the liver can retr; before them by the discharge of blood from its over-dilated vessels. Thus 1 distension of the liver not only leads to the beginning of the intestinal mo ment, but, by its disappearance and the tendency of the organ to return to undistended condition, leads to the completion of the recession and the provis: of space for the entering coils when and where it is needed, without any pressi on these coils.

The movement having started, all the evidence points to it being rapi( completed. Owing to the size of the caecum, possibly also owing to the gr< size of the dilated venous spaces found round it at this stage, and to the srr size and thick wall of the colon, the ccecum is retained in the sac to the last, a the proximal limb passes first into the abdomen. It does this, not en masse, 1 in continuity, slipping into the belly with its mesentery, the elongation of wh allows it to enter the abdomen, although the superior mesenteric vessels a the colic part of the distal limb are still in the sac. But the proximal limb already been seen to be on the right-hand side of the distal limb, so that it ent the abdomen below the right lobe of the liver, which retreats before it—that the coils of intestine enter the belly on the right-hand side of the median colic ‘ septu (Fig. 509) already mentioned. This ‘ septum ' of abdominal colon and mecolon is thus pushed over to the left by the coils, as seen in Fig. 510, and 1 back against the left dorsal wall of the abdomen, the coils lying on its vent (originally right) surface. Crossing in this way to the left, the coils necessak pass below the colic part of the distal limb of the loop and the mesenteric artery, wb*

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509

■The Condition within the Gut enters the Abdomen:

Umbilical Sac shortly before the Left and Right Views.

88 o

A MANUAL OF ANATOMY

is, as already seen, associated with this limb. Moreover, in going to the le and in pushing the median septum to this side, the coils have passed on tl dorsal side of the lower part of the omental bursa, which now hangs down ov them; this is the first form of the greater omentum of the definitive state, althou^ there is as yet no adhesion between the overhanging layers and the colon, ( between it and the dorsal wall.

The ccecum is the last structure to enter the abdomen, and, on entering, it li (Fig. 512) on the mass of coils of small intestine. It forms an angle, howeve with the rest of the colon when it lies in this situation, and as the colon is thic' walled, there is a tendency for the bent piece to straighten itself and come in line with the rest; this, and doubtless also the rapid increase in size of the coils the small gut, which now begins, cause the caecum to assume a right dors

Fig. 510.—Diagram of Section through Root of the Loop, showing ho its Cranial Limb, being below and on the Right of the Other, mu:

PASS BELOW THE CAUDAL LlMB AND THE MAIN VESSELS AND PUSH TP

Intra-abdominal Meso-colon to the Left.

Overhanging omental bursa is represented as rolled up.

position with reference to the mass of coils, on the right side of the neck of tl mass, and thus to come into its proper plane. This is found to occur a few da; after the entrance of the gut into the belly, and with its occurrence the secor stage comes to an end.

Third Stage. —It can be understood from a consideration of the figures that tl caecum and end of the colon, when they move to the right, must pass over ti line of the superior mesenteric artery, for the mesentery of the small intestn is attached along the line of the artery on its lower aspect. Thus the cole will come to lie across the duodenum, and the caecum below and to the rig! of this, and the artery will cross the duodenum lower down. This complet the twist of the mesentery of the loop, which finishes the second stage, ar leaves the peritoneal layers now in a position which can be understood from tl scheme in Fig. 463.

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881

The intestines are now essentially in their proper ‘planes/ and the third t e comprises only the developments and extensions in these positions that l to the conditions found m the adult. The descending meso-colon, laid

. 511.— Scheme to show Result >f Entry of Proximal Limb to rHE Right of Median Septum,

VHICH IT PUSHES TO THE LEFT >lND Dorsally against the Dorsal Wall: Cecum remains n the Sac.

Fig. 512.—Conditions immediately

AFTER THE ENTRANCE IS ACCOMPLISHED.

The caecum and mesenteric vessels lie on the mass of coils, the vessels to the right.

k against the left dorsal wall, as seen in Fig. 463, is, at the beginning of this

• e, relatively short, so that the left colon only reaches the inner edge of the

it aspect of the left kidney; as growth proceeds, this meso-colon lengthens,

5 r 3 -—Actual Conditions in Embryo just after Cecum has entered the Belly at the End of Second Stage.

1 the colon thus comes to lie farther out, finally reaching its definitive position, 1 the meso-colon becomes adherent to the dorsal wall. This dorsal adhesion presses from within outwards, and when the colon has reached its final posi 56

882

A MANUAL OF ANATOMY

tion, extends to the line of the gut, and thus fixes the bowel in situ. Or right side the colon, about the end of the third month, becomes attached v it crosses the duodenum, and at its caecal end. Between these two fixed the colon and meso-colon are free at first, but attachment of the meson just to the right of the superior mesenteric vessels is soon found. The l between the fixed parts slowly lengthens as the liver gets relatively sm and as it lengthens it becomes curved out with a convexity upwards and t right, ultimately forming in this way the hepatic flexure with the ascei and right portion of the tranvserse colon. The formation of these parts slow process, not really completed at birth. It is accompanied by an extei of the area of meso-colic adhesion, this, however, falling short of the lii advancing colon, so that this is free to lengthen farther. Thus the mesopart of the original loop mesentery becomes attached to the dorsal wall, the

Fig. 514.— Schemes to show Position of Meso-colon and Colon at Var

Stages, indicated by the Measurements.

a, b, left and right mesocolons; t, position at birth.

remaining free as the mesentery of descriptive anatomy; the line of attack of the mesentery is therefore in reality the limit of adhesion of the right meso-cc Between the upper end of the fixed meso-colon on the left and the att ment to the duodenum on the right the free colon and meso-colon are apj to the dorsal aspct of the lower part of the rudimentary lesser sac, invagina this somewhat. The colon stands away from the dorsal wall here, and it is dorsal surface of the meso-colon, the surface continuous with the adhe surfaces of the right and left meso-colons, that is applied (see Fig. 463) to wall of lesser sac. The adhesion of these applied parts to each other, extendir far as the position of the pancreas in the wall of lesser sac, brings into existence transverse meso-colon and the incidental attachment of the greater omentum tc transverse colon', by extension of the adherent area the bursal wall above pancreatic line becomes fixed to the dorsal wall, and constitutes the posU wall of the small sac.

Caecum and Vermiform Appendix. —The caecum appears about the week of embryonic life as a bud in connection with the distal limb of the U

THE ABDOMEN

883

intestine. It assumes the form of a blind diverticulum, which is at first of liform dimensions. It soon, however, becomes conical. The proximal part idergoes enlargement, and represents the permanent caecum. The distal part mains long and narrow, and represents the vermiform appendix, which ultimately jcomes connected with the left and posterior part of the caecum. The various )sitions occupied by the caecum and its migration to the right iliac fossa have st been referred to. Suffice it to say that it lies at first on the left side of the edian line, then it crosses to the right side, being at this stage below the liver, id finally is left in position as the liver retracts.

Peritoneal Structures.

1. Meso-gastrium. —It has been pointed out that the part of the dorsal minion mesentery which carries the stomach becomes pouched out to the left ; ie resulting sac is frequently termed the meso-gastrium, but more appropriately le rudimentary lesser sac (bursa omentalis). Its opening, to the right, is just x>ve the thick part of the mesentery known as the meso-duodenum, and is datively small. The sac is the result of rapid increase of a right-sided depression

the mesentery, the pneumato-enteric recess ; a left-sided recess shows itself

sry early, but disappears almost at once. The opening corresponds in the iult with the line of the pancreatico-gastric folds. The portion of the lesser sac etween these and the opening into lesser sac is added later as an additional

cess to the right of the mesenteric line, associated with the growth of the

iferior vena cava.

The rudimentary lesser sac is at first ‘ free ’ towards the left. After the return E the bowel, which (see Fig. 511) has caused the colon to invaginate its lower rail, the dorsal wall of the sac becomes attached to the abdominal wall, while the olon becomes fixed to its lower aspect. Thus the left half of the transverse leso-colon comes into existence, attached dorsally, while the pancreas, which ad extended in the back layers of the sac, now becomes fixed dorsally, the tyers behind it disappearing. The spleen forms in the outer part of the sac all, which, as the result of the fixation just described, has now a dorsal attachlent towards the left.

The outer part of the sac wall, thus left still ' free,’ is therefore the structure

rmed the ‘ meso-gastrium’ in the adult; the spleen, placed in this, is held by

to the dorsal wall on the one hand (lieno-renal fold) and, on the other, to the

omach (gastro-splenic ligament).

The greater omentum is evidently made by the bulging of the front and lower art of the rudimentary sac over the colon, to which it acquires a secondary ttachment. The lesser omentum (ventral mesentery) is drawn out from the upturn transversum.

2. The meso-duodenum is a thickening of the median mesentery just below the pening into the lesser sac. The duodenum is attached on its right front, and 1 at first a very short segment of the tube. The two pancreatic outgrowths ccur into the meso-duodenum, the upper one being immediately below the pening into lesser sac and opposite the attachment of its lower and back wall, ito which it extends. The lower growth, forming the head of the gland, enlarges 1 the meso-duodenum, with corresponding lengthening of the duodenum, which Iso begins to assume a curved form round the growing head. The whole curve f the duodenum is ultimately formed in this way as a result of the growth of the ead of the pancreas. It is clear, then, that this curve has nothing to do with tie rotation of the gut returning to the abdomen, but it is possible that the xtreme end of the duodenum may belong to the commencement of the proximal nib of the loop, secondarily fixed in position.

3 - Caecum. —The caecum, being originally a bud or outgrowth of the gut, has o mesentery, and is originally entirely surrounded by peritoneum.

4 - Vermiform Appendix. —The vermiform appendix, being originally the find narrowed end of the caecum, or, in other words, a diverticulum of the ‘Scum, is also destitute of a mesentery, properly so called, and is invested by

884

A MANUAL OF ANATOMY

an extension of the peritoneal envelope of the caecum. There is, however, most cases a fold of peritoneum pertaining to the vermiform appendix, whi extends along it for about one-half or two-thirds of its length. This fold called the meso-appendix or appendicular mesentery, and it is derived from t left or inferior layer of the mesentery proper, close to the ileo-colic junctic Its presence is due to the drawing out of vessels as the appendix is formed.

Structure of the Liver.

The liver has two coats, external and internal. The external serous coat is formed by the peritoneum, and is incomplete (see p. 77* Within the serous coat is the fibrous or areolar coat, which is kno\ as the fibrous capsule of the organ. It is for the most part thin, exce where the peritoneal coat is deficient. It is continuous all over t surface with the scanty amount of areolar tissue which pervades t interior of the organ and connects the hepatic lobules. At the por hepatis it surrounds the common hepatic duct, hepatic artery, ai vena portae, under the name of the capsule ofiGlisson. The subdivisio of this capsule accompany the various branches of the duct, arter and vein as these ramify throughout the liver in the portal cana'

The liver substance is composed of a gre number of small polyhedral masses, call hepatic lobules, which are closely pack< together, and at the centre of each of whi< is an intralobular or central vein. In m< there is very little areolar tissue between t] lobules, which are therefore for the most pa confluent. In some animals, however, notab the pig and camel, there is a very distin amount of areolar tissue between the lobule which therefore stand clearly apart from ea( other.

The average diameter of a hepatic lobule aV inch. One of its surfaces is called the has It is by this surface that the lobule is set upc the wall of a sublobular vein, and the intr lobular or central vein, having emerged fro: the lobule through the centre of its bas

Fig. 515.—Section of the Liver, showing a Large Hepatic Vein and its Tributaries (after Kiernan).

opens at once into the sublobular vein. The lobules, therefore, rel tively to the sublobular veins, on which they are ranged, are sessil When a sublobular vein is opened and viewed from within, an appearara something like mosaic work presents itself, the closely-set bases of tt lobules being visible through the thin wall of the vein, and the minut opening of the intralobular or central veins appearing in the centre ( each base. Each lobule is composed of hepatic cells, permeated b capillary networks of bloodvessels and bile-capillaries.

Bloodvessels. —The liver derives its blood from two sources—namely the portal vein and the hepatic artery. These two vessels, togethe with the hepatic duct, are invested by the capsule of Glisson at th

THE ABDOMEN

885

>rtal iissure. Iheir several branches, ensheathed by prolongations of lisson's capsule, ramify from this point throughout the liver, being intained in the system of canals known as portal canals. Each of these nals contains (1) a branch of the portal vein, (2) a branch of the jpatic artery accompanied by a plexus of nerves, (3) lymphatic vessels, id (4) a minute duct, all these being loosely surrounded by a prolonuaDn of Glisson’s capsule.

The portal vein ramifies within the liver like an artery. In the irtal canals its branches receive as tributaries small capsular and ginal veins , and they go on ramifying until they arrive at the interbular areas. Here they anastomose freely with one another around e lobules, and so form the interlobular plexuses . The branches which ise from these plexuses enter the lobules on all sides except their tses, and form in the interior of each lobule an intralobular plexus. -om this plexus a few radicles converge towards the centre of the bule, where they form by their lion the intralobular or central vein. le portal blood, though dark in lour, is very rich, being derived Dm, amongst other sources, the Dmach and small intestine.

The hepatic artery is a branch of n e coeliac artery. As its branches iverse the portal canals they give f capsular branches to the fibrous psule of the liver, and vaginal inches, which supply the walls of e vessels in the portal canals, as ill as their Glissonian sheaths. The anches of the artery finally end minute interlobular arteries , which pply the walls of the interlobular

ins and bile-ducts. According to Fig. 516.—Two Hepatic Lobules me authorities they send minute (highly magnified).

pillary branches into the interior lobule showing the intralobular each lobule to join the mtra- plexus; B, lobule showing the

Dular plexus of the portal vein, but hepatic cells,

is view is not held by others.

The function of the hepatic artery and its branches is to nourish e tissues of the liver, whilst the portal blood supplies the materials fich are elaborated by the hepatic cells.

( The hepatic veins commence in the centre of each lobule as an ralobular or central vein. The intralobular veins open into the blobular veins, which are closely adherent to the bases of the lobules.

sublobular veins join to form larger sublobular veins, and these turn terminate in the hepatic veins, which are not in direct contact th the lobules. The hepatic veins pass to the fossa for vena cava on 2 posterior surface of the liver, towards which they converge, taking

886

A MANUAL OF ANATOMY

up sublobular veins in their course. The passages which contain t veins are known as the hepatic canals. On arriving at the upper p; of the fossa for vena cava they are reduced to two or three in numb which pour their contents directly into the inferior vena cava. It is be noted that the hepatic veins converge to the fossa on the poster surface, whilst the branches of the portal vein radiate in all directic from the portal fissure. The hepatic veins are accompanied only lymphatic vessels, and are surrounded by a very scanty amount areolar tissue, which explains why they present open mouths when c across.

Distinguishing Characters of the Hepatic and Portal Veins—Hepatic Veins

(i) These present open mouths when cut across. (2) They are accompan only by lymphatic vessels. (3) Their walls are very thin, and are practica in direct contact with the substance of the liver. (4) They converge towa: the caval fossa on the posterior surface.

Portal Veins. —(1) The mouths of these veins are practically closed or c lapsed when cut across. (2) The veins are accompanied by branches of hepatic artery, and by ducts. (3) Their walls are fairly thick, and are separa from the substance of the liver by the sheaths derived from Glisson’s capsi (4) They radiate in all directions from the porta hepatis in portal canals.

Hepatic Cells.— These are situated within the lobules. 1 hey c polyhedral, granular cells, having a diameter of T 7 T u_ inch, and ea contains a round nucleus. They have no cell-wall, properly so call* and they are connected by a delicate supporting tissue. Ihe ce. which are capable of amoeboid movement, lie between and around t capillary vessels, where they are arranged in radiating rows convergi towards the centre of the lobule.

Bile-ducts. —These commence within the lobules as bile-capillar or bile-canaliculi , which are in reality intercellular passages. Th have a very delicate wall, and are bounded on all sides by the hepa cells—hence the name intercellular passages. According to Pflih and Kupffer, the cells contain vacuoles, which communicate by int: cellular passages with the bile-capillaries. The hepatic cells intern between the bile-capillaries and the capillary bloodvessels. At t circumference of the lobule the bile-capillaries pass into the sm interlobular bile-ducts. These join to form larger ducts, and these turn go on joining until, on arriving at the porta hepatis, only t ducts result, which emerge one from each lobe. These now join to fo: the common hepatic duct, and this joins the cystic duct to form the bi duct. The walls of the interlobular ducts are very thin, being co posed of a basement membrane lined with polygonal epithelium. Tlarger ducts in the portal canals have thicker walls, which, from withe inwards, are composed of a fibro-elastic coat, containing plain muscu tissue, arranged longitudinally and circularly, and a mucous coat lir with columnar epithelium. The mucous membrane of the larger du< presents numerous openings, which lead into blind mucus-secreti recesses. The structure of the hepatic and bile-ducts is similar to t preceding, though on an increased scale.

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v,HEP

887

Lymphatics.—The lymphatic vessels of the liver are arranged in 0 groups—superficial and deep.

Superficial Lymphatics.—These form plexuses beneath the perileal coat, and have different destinations.

Supero-anterior Surface. —(1) The lymphatics from the vicinity of 3 falciform ligament enter that ligament, and, passing through the iphragm into the thorax, they terminate in the anterior group of the pradiaphragmatic glands. (2) The lymphatics from the right part the superior surface and those from the right lateral surface enter 3 right triangular ligament, and, ssing through the diaphragm, they -minate in the middle group of the perior diaphragmatic glands of the r ht side. (3) The lymphatics from 3 left part of the superior surface d those from the left extremity ter the left triangular ligament, and ss to the peri-cesophageal glands in ation to the lower end of the >ophagus, the efferent vessels of lich terminate in the cceliac glands.

1 The lymphatics from the anterior rt of the supero-anterior surface, cept those from the vicinity of the ciform ligament, turn round the terior border of the liver, and end the hepatic glands within the lesser lentum. (5) The lymphatics from ^ 517 ' Lymph Glands in the

e posterior surface of the right lobe Rouviere). ss between the two layers of the HEP, hepatic group,round the artery ronary ligament, and, having pierced and concerned with deep hepatic e diaphragm, they terminate in the na caval group of diaphragmatic mds within the thorax.

Inferior Surface. — (1) The lymtatics from the greater part of the ferior surface of the right lobe, intding those of the quadrate lobe, ss to the hepatic glands. (2) The lymphatics from the posterior ad of the inferior surface of the right lobe pierce the diaphragm, td end in the caval glands. (3) The lymphatics from the greater ad of the caudate lobe pierce the diaphragm, and end in the caval mds ; whilst those from the lower part of this lobe pass to the hepatic mds. (4) The lymphatics from the inferior surface of the left lobe ss to the hepatic glands.

Deep Lymphatics.—These vessels form two distinct sets. Some them accompany the branches of the portal vein, and having emerged rough the porta hepatis, they terminate in the hepatic glands. Others

drainage; B, a cystic gland above, and (below) a gland connected with this and with the retroduodenal gland ; D, above the head of pancreas. These glands are njore particularly concerned with the drainage of the system of biliary ducts.

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A MANUAL OF ANATOMY

pass with the hepatic veins to the caval fossa of the liver, and thereal they enter the thorax along with the inferior vena cava, their destinat being the caval glands.

Nerves.—The nerves of the liver are derived from the hepatic plex which is an offshoot of the coeliac plexus. The coeliac plexus, thoi principally composed of sympathetic fibres, is reinforced by a 1 twigs from the right vagus nerve. The hepatic plexus accompanies hepatic artery to the porta hepatis, where it receives branches from left vagus nerve, which have ascended from the antero-superior surf of the stomach between the two layers of the lesser omentum. In liver the nerves, which are chiefly non-medullated, are distributed the walls of the bloodvessels and ducts, penetrating as far as the inf spaces between the hepatic cells.

Development of the Liver.

Liver. —The hepatic cells and the epithelium of the bile-ducts are of er dermic origin, whilst the connective tissue of the gland and its vascular c stituents are developed from the mesoderm.

The rudiment of the liver appears as a longitudinal groove on the inner asp of the ventral wall of the duodenal portion of the primitive gut. This gro<

Fig. 518.— Sagittal Section through Septum Transversum and Caud End of Fore-gut in an Embryo of 4-5 Mm., to show Hepatic Divi

TICULUM AND GROWTH OF HEPATIC CYLINDERS AND GALL-BLADDER.

The cylinders have broken up the vitelline veins, represented here by the por vein, into sinusoids. The entoderm is shown by solid black.

gives origin to a diverticulum or evagination of the entoderm of the vent duodenal wall, called the hepatic diverticulum or liver-bud, which has at firsi wide communication with the gut. At a later period this communication becon constricted, and forms a pedicle, which, after undergoing elongation, gives r to the bile-duct. From this pedicle, close to the duodenal wall, the venti diverticulum of the pancreas arises.

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889

The hepatic diverticulum or liver-bud invades the lower or caudal layer of septum transversum, composed of mesoderm, within which it bifurcates > two divisions, the right and left hepatic ducts.

The cells of these two divisions of the hepatic diverticulum undergo proration within the mesoderm of the lower layer of the septum transversum, thereafter each division breaks up into a number of solid trabeculae, which known as the hepatic cylinders. These cylinders give off secondary solid Deculae, and these again ramify extensively. The subdivisions of the various eeculae anastomose freely, and in this manner intricate networks are formed und the vitelline and umbilical veins, which veins traverse the septum isversum as they pass to the sinus venosus. The hepatic cylinders invade se veins, carrying the endothelial walls of the vessels before them. The is are thus freely subdivided into ad-channels, which are known as sinuIs. These sinusoids form capillary works, which occupy the meshes of net-works formed by the hepatic inders.

Many of the solid trabeculas become •ular, and give rise to the bile-capiles or bile-canaliculi, and bile-ducts.

iers give rise to the hepatic cells.

3 liver thus consists originally of incite reticula of solid cellular trabeculce, hepatic cylinders, disposed around the lline and umbilical veins.

As the liver increases in size it profs downwards, carrying with it the r er layer of the septum transversum, ich forms its capsule and connective

ue. The organ now lies between the

a layers of the ventral mesentery, ich gives rise to—(1) the falciform iment; (2) the coronary ligament; and the lesser omentum (see p. 79).

About the middle of intra-uterine life

liver occupies a large part of the

lominal cavity, and the right and left >es are of equal size. In the latter If of intra-uterine life, however, the ht lobe gradually attains greater size in the left. About the period of birth s liver extends almost as low as the ibilicus. After birth it undergoes dimition in size, the circulation of placental >od through it by the umbilical vein having been permanently arrested at th. The liver decreases in relative size largely owing to slower growth, but ire is also actual degeneration of part of its substance already formed. This plains the occurrence of degenerated remnants, vasa aberrantia and Kiernan s 1 ules, found near its edge, in the left triangular ligament and by the inferior tia cava.

At an early period in development the liver has indications of four lobes, 0 vitelline and two umbilical, but these are not so well marked as in some ier animals. The umbilical lobes form the two lateral lobes, but the vitelline )es are lost in the parts round the vena cava. The other small lobes on the

ceral surface are secondary, formed round large vessels or from surface relays; the free extremity of the caudate lobe has a small process which is the

nnant of a part originally projecting into the bursa omentalis through its sning.

Fig. 519. —The Excretory Apparatus of the Liver.

G, gall-bladder; F, fundus; CD, cystic duct; H, common hepatic duct; B, bile duct; P, pancreatic duct; A, ampulla in duodenal wall into which both ducts open.

8 go

A MANUAL OF ANATOMY

The hepatic cylinders appear solid, but they contain no doubt poten lumina. These become apparent as bile-capillaries about the beginning of fourth month.

Hepatic lobules are not well formed before the first few years after bi] They are produced as a result of growth and branching of terminal twigs of hepatic veins, round which the cylinder cells group themselves, with their po vessels.

Structure of the Gall-bladder. —The wall of the gall-bladder composed of three coats—serous, fibro-muscular, and mucous.

The serous coat is formed by the peritoneum, and is usually inco plete, being confined to the inferior and lateral surfaces. Son times, however, the peritoneum completely surrounds the organ, a attaches its superior surface to the fossa for gall-bladder of the liver a ligamentous fold.

The fibro-muscular coat is composed of fibrous and plain muscu tissues. The fibrous bands are disposed in all directions, and int lace freely with one another. The muscular fibres, which int

mingle with the fibre bands, are arranged be longitudinally and trai versely. Around the t minations of the bile-di and pancreatic duct a their continuation ir the ampulla the circul muscular fibres are abr dant, forming the sphino of Oddi (Fig. 520).

The mucous coat covered by columnar ej tfiehum. Its surface presents a great number of small ridges, whi interlace in all directions and enclose polygonal depressions or alve of various sizes. This pitted appearance bears a resemblance honeycomb, and the mucous membrane of the seminal vesicle of t male is similarly arranged. The mucous coat is richly provided wi mucous glands. In the neck of the gall-bladder, which describes t\ cui ves, there are two fibro-mucous folds, which project into the interie one opposite each curve, and serve as valves.

Structure of the Cystic Duct. —The wall of the duct is compos* of a fibro-elastic and muscular coat and a mucous coat. The form 1 esembles that of the gall-bladder. The mucous coat, which is cover* Li' co ^ umnar epithelium, presents several crescentic folds dispos* obliquely round the wall in a spiral or somewhat corkscrew manne and succeeding each other at frequent intervals. When the duct distended, its exterior presents a series of spiral constrictions wii intervening swellings. The spiral folds in the interior serve as valve which are known as the spiral valve (valves of Heister).

Blood-supply. —The gall-bladder is supplied by the cystic arter which is a branch of the right division of the hepatic. Its cour:

Sph. of Pancreatic Duct

.Sph. of Bile Duct

r ^ Longitud. Fibres

Duodenal Pap.

Iug. 520.—Sphincter of Oddi (after

Hendrickson).

THE ABDOMEN

891

forwards between the hepatic and cystic ducts to the neck of the gan, where it divides into two branches, superior and inferior. ie superior branch ramifies on the upper surface of the organ, between and the fossa for gall-bladder of the liver, whilst the inferior branch distributed over the inferior surface beneath the peritoneum. The stic vein, which is formed by the union of superior and inferior anches, usually opens into the right division of the portal vein. >me of the veins from the gall-bladder may enter the liver to join e right branch of the portal vein. This fact explains the venous emorrhage which sometimes occurs when the gall-bladder is lifted it of its fossa.

Lymphatics. —These pass between the two layers of the lesser nentum to the hepatic glands.

Nerves. —These are derived from the hepatic sympathetic plexus.

Development of Gall-bladder and Duct.— An early stage is seen in Fig. 518. ie hepatic diverticulum is elongated in the line of the gut, and its lower end dilated to form the gall-bladder, the upper part alone giving origin to hepatic linders. The lower part of the groove is blocked by cell-growth, the bladder us opening into the upper part which will become the liver-duct. The bladder; latation grows ventrally in the mesoderm below the liver, its neck thus being retched out between the duct and the bladder, and becoming the cystic duct.

Structure of the Pancreas.

The pancreas belongs to the class of compound racemose or acinolbular glands, and bears a close resemblance to a serous or true ilivary gland— e.g., the parotid. It has a greyish-pink colour, and somewhat soft in consistence. It is from 6 to 8 inches long, from to 1^ inches deep, except at the right and left extremities, and from to | inch thick. Its weight is about 3^ ounces. It is destitute of fibrous capsule, properly so called, and is invested merely by a thin onnective-tissue covering, which readily allows the outline of the )bules to be seen.

It is composed of a number of lobules, which are loosely held ogether by ducts and areolar tissue. Each lobule consists of a group f alveoli or acini which are long, tubular, and convoluted, wherein hey differ from the saccular alveoli of such a gland as the parotid. Tom each lobule a duct passes off, which unites with the ducts of djacent lobules in the left extremity of the gland to form the commencement of the principal duct. Within the lobule the lobular duct 5 formed from junctional ducts, each of which belongs to an acinus, nd is lined with flattened cells.

The alveoli or acini are each composed of a basement membrane, eticular in structure, and lined with secreting columnar epithelium, he basement membrane being continuous with the wall of the junctional luct. The lumen of each acinus is small, and is usually occupied by pindle-shaped cells, known as the centro-acinar cells of Langerhans, vhich are continuous with the cells of the junctional duct, dhe

892 A MANUAL OF ANATOMY

connective tissue which covers the pancreas sends expansions inw between the lobules, along which the bloodvessels are condu( Further, the interlobular connective tissue penetrates into the lob and so conducts the bloodvessels into their interior. The interalv i

connective tissue has a loose position, and in certain parts tains small groups of epithelium cells, surrounded by large convol capillary vessels. These gr< constitute the islets of Langerh which are characteristic of pancreas.

Excretory Apparatus of the 1 creas. —There is one principal d called the pancreatic duct (due Wirsung). It is buried in the i stance of the gland, and is rea recognized by its white colour, lies nearer the posterior than anterior surface, and rather ne; the lower than the upper part of gland. It commences in the whence it runs through the b as far as the neck, receiving in course a great many tributai On arriving at the neck it eff< a communication with the ac< sory pancreatic duct, then descri a bend, and passes into the head in a direction downwards, backwai and to the right. Finally, on leaving the pancreas it meets the t duct, and the two, entering the wall of the second part of the duodem terminate in the manner already described (see p. 779).

The accessory pancreatic duct (duct of Santorini) is comparativ small, and varies much in size. If well developed, it commen in the lower part of the head, where it takes up the ducts of the lobi of that part. It then passes upwards with an inclination to the right, c divides into two branches. One of these joins the pancreatic main d 1 in the neck, whilst the other opens into the second part of the duoden at a point about 1 inch above the common opening of the bile-di and the pancreatic duct. The secretion conveyed by the access( duct is believed in early life to flow into the duodenum, whereas in 1 adult it is largely diverted into the pancreatic duct.

The tributaries of the principal duct, as well as of the accessc duct, when followed into the pancreas, become in succession int lobular and intralobular ducts. The intralobular ducts pass wit! the lobules, and end in intermediary , junctional, or intercalary* due with which the alveoli or acini are directly connected. The p£

Interposed or inserted between the alveoli and the intralobular ducts.

Alveoli Islets of Langerhans

Fig. 521. — Structure of the Pancreas (highly magnified).

THE ABDOMEN

893

he duct between the intermediary and the intralobular duct is 3d the neck. The walls of the intermediary ducts are thin, and formed of a basement membrane covered by flattened epithelial 5, the neck being lined by polyhedral cells. In the larger ducts Dnnective-tissue coat is superadded to the basement membrane, ch is now covered by columnar epithelium. The pancreatic duct, igh of comparatively large size, has a thin wall destitute of muscular 3s except near its termination, and composed of two coats— irnal fibrous and internal mucous. The mucous coat is smooth and ered by columnar epithelium.

Varieties— (1) Small Pancreas. —This consists in a permanent detachment he unciform process, or that part of the pancreas which extends along the er aspect of the third part of the duodenum and has the superior mesenteric els in front of it. (2) The head of the pancreas may surround the second

of the duodenum more or less completely. (3) Accessory Pancreas.—

n an accessory pancreas is present it is usually met with in the wall of the

Fig. 522.—The Pancreas and its Ducts (Posterior View).

A

>er part of the jejunum, but it may be found in the wall of the stomach or >er part of ileum. (4) The pancreatic duct sometimes opens into the duodenum 3 pendently of, but close to, the bile-duct.

Blood-supply. —The pancreas derives its arteries from (1) the lcreatic branches of the splenic artery, one of which accompanies principal duct from left to right, and is known as the arteria panitic magna; (2) the superior pancreatico-duodenal of the gastro)denal from the hepatic; and (3) the inferior pancreatico-duodenal

he superior mesenteric.

The veins are (1) the pancreatic veins, which open into the splenic n; and (2) the pancreatico-duodenal veins, which terminate in

superior mesenteric or portal veins. All the pancreatic venous

od eventually passes into the portal vein.

Lymphatics. —These commence as lymphatic clefts around the eoli, and pass chiefly to the cceliac glands. Some of them, however, minate first in the superior mesenteric glands in contact with the per part of the superior mesenteric artery.

Nerves. —These are derived from offshoots of the hepatic, splenic, i superior mesenteric plexuses, and accompany the arteries. They 5 chiefly composed of non-medullated fibres.

Uncinate Process

Pancreatic Duct

Pancreatic Duct

Accessory Duct

Bile Duct

894

A MANUAL OF ANATOMY

Development of the Pancreas. —The tubular portion of the pancreas entodermic origin, but its connective tissue and vascular elements are deve from mesoderm.

The pancreas is developed from two entodermic diverticula—dorsa ventral. The dorsal diverticulum is an evagination of the entoderm of the wall of the duodenal portion of the primitive gut. The ventral diverti( springs from the primitive hepatic diverticulum close to the ventral wall ( duodenum, which diverticulum subsequently forms the bile-duct. The < diverticulum extends between the two layers of the meso-gastrium, wh comes into relation with the developing spleen. This diverticulum giv lateral epithelial tubes, which ramify freely, and so build up an acino-tu

Fig. 523. —Diagram to show the Relations of the Pancreatic Outgrowths to the Median Mesentery.

The dorsal wall of the duodenum is left on the meso-duodenum, and bet this and the oesophagus the stomach has been removed with the front of the bursa omentalis, leaving the posterior wall and opening of the The ventral outgrowth A is growing in the meso-duodenum, but the d growth, being higher up, is able to extend into the wall of the primitive The portal vein passes backwards, upwards, and to the right betweei two outgrowths.

gland. The acini appear as enlargements of the walls of the terminal t By means of the ramifications of the dorsal diverticulum the greater part o head, body, and tail of the adult pancreas are formed.

The ventral diverticulum is at first double, right and left outgrowths ar from the liver-hud. The left formation quickly disappears, while the right coming into relation with the portal vein, grows round this into the meso-duode\ where it enlarges, being placed with the vein behind the duodenum as this ci out toward the right. It forms the pancreatic duct, and gives outgrowtl form the lower part of the head of the pancreas.

The ventral and dorsal parts of the pancreas join, and the dorsal d ticulum (pancreatic duct) and ventral diverticulum now communicate by fi anastomosing branches. Thereafter the duodenal portion of the pancr»

THE ABDOMEN

895

ict usually atrophies and disappears. It may, however, persist, and open as l independent duct into the second part of the duodenum. The accessory iiicreatic duct is persistent, and constitutes the principal duct of the fully iveloped pancreas. From its mode of development it necessarily opens into e bile-duct.

The islets of Langerhans, which are characteristic of the pancreas, are formed cells derived from the walls of the original epithelial tubes. These cells become fferentiated, and by their multiplication they give rise to isolated cell-groups, ing in the mesodermic connective tissue between the lobules of the gland, where ey are soon permeated by bloodvessels.

The development of the head of the pancreas proceeds within the meso-duonum (Fig. 523) dorsal and caudal to the vitelline vein, which enters the mesolodenum here to form the beginning of the portal vein. The head, by its large owth, widens out the meso-duodenum to a very considerable extent, and oduces the curve of the duodenum round its mass. The body and tail of the gan extend into the dorsal wall of the bursa omentalis, growing rapidly in this ward the left. They thus come to be directed transversely, and are laid down the dorsal wall of the abdomen. When the peritoneum of this wall adheres the bursal wall, and the two adherent layers disappear, the gland is left in a ro-peritoneal position behind the completed lesser sac; rarely, however, the hesion and disappearance of the layers is incomplete, and thus a cyst may be

med behind the gland from fluid within a persisting part of the peritoneum

re.

Structure of the Spleen.

The spleen is the largest ductless gland in the body. It has two ats, serous and fibrous, inseparably connected together. The serous at is formed by the peritoneum. The fibrous coat or tunica propria composed of fibrous tissue, with a considerable admixture of elastic

sue, and a certain amount of plain muscular tissue, all of which

lild up a strong distensible tunic.

The organ is composed of a trabecular network, the spleen pulp, oodvessels, and Malpighian corpuscles.

The tunica propria sends into the organ a number of trabecube fich, like the tunica propria, are composed of fibrous, elastic, and ain muscular tissues. These divide and subdivide, and unite with e another, as well as with processes derived from the sheaths which e bloodvessels carry in with them at the hilum. There is thus pied a trabecular network, which pervades the interior, and conins in its meshes the splenic pulp, capillary tufts, and lymphatic 'dules.

The splenic pulp occupies the meshes of the network formed by the ibeculae. It is soft, and has a dark red colour, which, however, comes brighter on exposure to the air. The matrix of the spleen [ lp is reticular, and is formed by branched connective-tissue coracles, which constitute the sustentacular cells of the organ, the drix is, therefore, in reality retiform tissues. The interstices of e reticulum contain blood, in which there is a large number of white rpuscles, and also special cells characteristic of the spleen, and fied the splenic cells. These latter are of large size, and are amoeboid. iey contain pigment, and red blood-corpuscles in various stages of integration.

8 g6

A MANUAL OF ANATOMY

Bloodvessels and Lymphatic Nodules (Malpighian Corpuscle! Arteries.—The splenic artery furnishes five or six large branches wl enter the organ at the hilum, and carry in with them trabecular shea from the tunica propria. In the interior they divide and subdiv and finally terminate in pencil-like clusters of capillary vessels, which time they have laid aside all their coats except the endotht lining. The endothelial cells then become separated from each ot by spaces, and being continuous with the sustentacular cells of spleen pulp, the blood flows directly into the interstices of the reticu] of the pulp. The arteries, which are at first accompanied by trabeci sheaths, ultimately lose these sheaths, and enter the splenic pulp

end in clusters of capillaries, fore they terminate in these c' ters their external coat underg an important modification, wl consists in its transformation i lymphoid or adenoid tissue. 1 lymphoid tissue forms at inten small round or oval enlargemei called lymphatic nodules (Ma ghian corpuscles), which on sect appear as minute white speck; the dark red spleen pulp. Tb corpuscles are simply local! expansions of the lymphoid tis which forms the external coat the small arteries. The expans may be confined to one side the artery, or it may include whole of its circumference. E; corpuscle receives minute tv from the artery on which it is i and contains large numbers lymph corpuscles, as well capillary bloodvessels.

Veins.—The arterial blood, on leaving the capillary vessels, tie directly into the interstices of the reticular matrix of the spleen pr and from these it is taken up by radicle veins which commence b manner similar to that in which the capillaries end. Endothe cells, continuous with the sustentacular cells of the pulp, come togetl and cohere, so as to form very delicate tubular vessels having clo! walls. As these radicle veins unite and become larger the other co are superadded to the endothelial lining. Ultimately five or six ve leave the spleen at the hilum, which unite to form the splenic vei

this in turn uniting with the superior mesenteric vein to form the poi vein.

It is to be noted that, in the circulation through the spleen, j arterial blood leaves tubular vessels and flows through the interstij

Capsule Trabecula

Lymphatic Nodules Splenic Pulp

Fig. 524. —Section of the Spleen.

THE ABDOMEN

897

he reticulum of the spleen pulp, where it bathes the Malpighian niscles, after which it enters tubular vessels of the nature of veins, rhe cells of the spleen are of three kinds as follows: (1) the sustenilar cells of the retiform tissue of the spleen pulp; (2) the splenic>; and (3) lymphoid corpuscles.

Lymphatics. —These are arranged in two groups—trabecular and vascular. The trabecular lymphatics are contained in the trails, and communicate with a lymphatic network in the tunica pria underneath the peritoneal coat. The perivascular lymphatics mence in the lymphoid tissue which forms the external coat of smaller arteries. At the hilum both sets of lymphatics meet and 3 to the splenic glands, and thence to the coeliac glands.

Nerves. —These are derived from the splenic plexus, which is an hoot from the coeliac plexus. The fibres, which are mostly nonLullated, are derived partly from the sympathetic system and partly n the right vagus nerve.

)evelopment of the Spleen. —The spleen is formed from the mesodermal of the bursa omentalis. In the fifth week the sac wall in its upper, dorsal, left part shows a certain amount of thickening, with vascularization, and 2ase in size of the mesothelial cells covering its outer surface. A little later e covering cells proliferate, and cells pass from the layer into the mesenchyme le wall. As the mass enlarges it projects outwards into the peritoneal cavity.

he processes take place at several points the organ is lobed; although the

d appearance is lost by subsequent fusion, the original divisions are indicated

he fissures. The cells arrange themselves in trabecular bands, and small

gather round the small branches of the splenic artery and form the lymphatic lies (Malpighian corpuscles) about the seventh month. When the dorsal of the bursa omentalis becomes adherent to the wall of the abdomen, the sn, lying just outside the area of adhesion, is now attached to the outer edge his area by the intervening strip of non-adherent sqc wall— i.e., by what is wn as the lieno-renal fold. As it projects toward the left, away from the ty of the sac, it is covered by peritoneum of the greater sac, and is separated 1 that of the lesser sac by the vessels in the wail of the latter.

Structure of the Suprarenal Glands.

The suprarenal glands [adrenals) belong to the so-called ductless ids. Each gland is enclosed in a thin sheath of connective tissue, n the deep part of which processes are given off into the interior, ire they form a supporting stroma. The proper substance of the id is divided into an external or cortical, and internal or medullary t.

The cortex has a somewhat yellowish tint, due to the presence of poid substance, and is composed of cells supported by a fibrous )ma. The cells being variously arranged in different parts, the tex is divisible into three zones, named, from without inwards, zona nerulosa, zona fasciculata, and zona reticularis. The zona glomerul > which is narrow, lies immediately within the external capsule, I- is so named because its component cells are grouped in such tanner as to form glomeruli, which are embedded in a fibrous stroma.

57

898

A MANUAL OF ANATOMY

The cells are polyhedral, and each contains a clear round nucl The zona fasciculata forms the chief part of the cortex, and is so na] because its component cells are arranged in columns or fasciculi, cells are similar to those of the zona glomerulosa, and the cell coin are separated from one another by fibrous trabeculae, which aci carriers of the bloodvessels, nerves, and lymphatics. The zona ret laris, which is narrow, lies within the zona fasciculata, and is so nai because its component groups of polyhedral cells are connected \ one another in such a manner as to form a reticulum.

The medulla is confi

Capsule \

Cortex

Medulla

Zona Glomerulosa

> Zona Fasciculata

Zona Reticularis

Fig. 525. —Section of the Suprarenal

Capsule.

to the centre of the gl in the adult, is soft in c sistence, and has a redd brown colour, due to contained venous blood, supporting fibrous strom; the cortex pervades it, ; is arranged in a retici manner. The meshes of 1 reticulum are occupied cells, larger and more irre lar than those of the corl further differing from tf in containing granules wf stain deeply with chromi salts.

Blood-supply—Arteries

These are (1) the supei suprarenal of the phre from the abdominal aoi (2) the middle suprare from the abdominal aoi and (3) the inferior sup renal from the renal.

The veins of each gh eventually unite to form <

suprarenal vein. This vessel emerges through the hilum, and on right side it opens directly into the inferior vena cava, whilst on left side it terminates in the left renal vein.

The lymphatics terminate in the juxta-aortic glands . The lyi vessels accompany the vessels connected with the glands. T1 issuing with the main vein drain the medullary region, and ] (Fig. 526) to aortic glands below the levels of the renal pedicles; on two pass behind these to glands behind the renal arteries. Yes accompanying the suprarenal arteries drain the cortex, and reach gla above the renal pedicles; on the right some pass behind the infe vena cava. Additional lymphatics, shown in the figure by interruj lines, run up on the diaphragm, which they pierce, to enter glands

THE ABDOMEN 899

thoracic aorta at about the level of the ninth or tenth thoracic tebrae.

Nerves. —-The suprarenal glands are very richly supplied with nerves, ch are derived from (1) the phrenic plexus from the coeliac ganglion . coeliac plexus, (2) the suprarenal plexus from the coeliac ganglion . coeliac plexus, and (3) offshoots from the renal plexus. According Bergmann, the suprarenal glands also receive fibres from the phrenic . vagi nerves. The fibres, which are chiefly non-medullated, form l plexuses in the medulla, where they have numerous ganglion cells nected with them.

Fig. 526. —Lymphatics of Suprarenal Glands (after Rouviere).

Development. —The suprarenal gland makes its appearance medial to the •onephros. The cortex is of mesodermic origin, and the medulla is developed n the cells of the primitive abdominal sympathetic system.

The cortex is developed from cellular outgrowths of the mesothelium of the om, or body-cavity, on the mesial aspect of the mesonephros. These outwths soon become separated from the ccelomic mesothelium, and unite to n a solid mass, which constitutes the cortex.

The medulla is derived from the primitive abdominal sympathetic cells, 'ups of cells grow out from the ganglia (these cells being consequently of Mermic origin), and they invade the cortex. They become differentiated ^ two groups. The cells of one group are chromaffivi cells, and stain a dark ow colour with chromic acid salts. The cells of the other group are ganglion All the cells developed from the sympathetic ganglia gradually pass to the tre, where they constitute the medulla.

900

A MANUAL OF ANATOMY

The suprarenal gland thus develops in two parts—cortex, derived fron coelomic mesothelium (mesoderm), and medulla, derived from the abdor sympathetic ganglia, and therefore of ectodermic origin. The cortical begins to form in the fourth week, and the ganglion cells begin their inv: three weeks later; the process goes on till after birth, and ill-understood fc tive changes continue for some years.

Structure of the Kidneys.

The kidneys are compound tubular glands. Each organ is vested by a capsule, composed of fibrous tissue with a certain aim of elastic fibres. The deep surface of this capsule is attached tc peripheral portion of the renal substance by fine fibrous processes

small bloodvessels. Ur neath it there is a cei amount of plain muse fibre, arranged in a sc what plexiform manner, the hilum on the inner bo it is prolonged inwarck line a cavity to which hilum leads, called the t sinus, where it becomes tinuous with the fibrous c of the calyces.

When a kidney is into two halves by a lc tudinal incision carried f the outer to the inner bo it is seen to be comp< of two parts—cortex medulla.

The medulla, whicl internal in position, is ranged in conical bum termed renal pyramids (pyramids of Malpighi), which vary in nun from eight to eighteen, the average number being about twe The bases of these pyramids are directed towards the circumfere: whilst their apical parts, called renal papillae, project into the sinus, wl they are grasped by the calyces. Each renal pyramid is divided : three parts—namely, the basal part, the papillary zone, and the a ; The basal parts of the pyramids form collectively the boundary zon the kidney. They abut against the cortical substance, which se prolongations between them, called renal columns (columnar BerU These prolongations extend as far as the commencement of the ap parts of the papillary zones, where they cease, so that these ap parts project into the calyces free from cortical investments. E renal pyramid is composed of straight, slightly converging urinifei tubules (tubuli recti ) and straight bloodvessels, the number of tub

Renal Pyramid

Calyx

-Pelvis

— Ureler

Fig. 527.—Diagram of the Kidney in Longitudinal Section.

THE ABDOMEN

901

ig very much greater in the basal part than elsewhere. This ight arrangement of tubules and bloodvessels imparts to each amid a longitudinally striated appearance from apex to base. The al parts have a dark reddish-brown colour, which becomes brighter he papillary zones.

The cortex of the kidney is mainly situated within the fibrous sule. It has a reddish-brown colour, and, as already stated, sends longations between the renal pyramids. Like the medullary part,

composed of uriniferous tubules and bloodvessels, but the tubules

principally convoluted (tubuli contorti), though there are also dies of straight tubules (tubuli recti) which have issued from the il pyramids, and form the medullary rays.

Cortex. —The cortical part is composed of the labyrinth and the lullary rays.

Labyrinth .—This portion of the cortex is so named from the very iplicated arrangement of its tubules. It is situated in the internes between the medullary rays, and is composed of convoluted dferous tubules, bloodvessels, and glomeruli, each of the latter being losed within a capsule of Bowman.

Uriniferous Tubules. —Each tubule commences in the labyrinth he cortex in a spherical dilatation, called the capsule of Bowman, tiin which there is a tuft of convoluted capillary bloodvessels, known i Malpighian glomerulus (Malpighian corpuscle). Bowman s capsule sents two poles. One of these is formed by two bloodvessels, afferent efferent, which pierce the capsule at separate points, but close to each er. At the other pole Bowman’s capsule becomes constricted, and ns the neck of a cylindrical tubule. After the tubule has passed the k it becomes convoluted, and forms the first convoluted tubule. The

sment membrane and lining epithelium of Bowman’s capsule are conious with the basement membrane and lining epithelium of the first voluted tubule, and the space between Bowman’s capsule and the nerulus is continuous with the lumen of the tubule. The first voluted tubule soon becomes straight, though slightly wavy, and, Ting a medullary ray, it forms the spiral tubule. This tubule, on 'hing the junction of the cortex and boundary zone, becomes denly very narrow, and traverses the basal part of a renal pyramid, s known as the descending limb of Henle’s loop. On leaving the ndary zone it enters the papillary zone, and after a short course escribes a very sharp bend, called the loop of Henle. It now re'es its steps from the papillary zone into the boundary zone of a al pyramid, in which latter situation it becomes suddenly enlarged, s part, which retraces its steps, is called the ascending limb of Henle’s »• It re-enters the cortex, where it becomes narrower, and passes > a medullary ray, in which it lies for a short distance. It subaently, however, leaves the ray, and, entering the labyrinth, ds between the convoluted tubules as the irregular or zigzag tubule, ch has become slightly enlarged. This irregular tubule then passes 1 the second convoluted tubule. This tubule, becoming narrow,

go2

A MANUAL OF ANATOMY

passes into the junctional tubule, which is slightly wavy. The tional tubule leads into the straight or collecting tubule, which is slij enlarged, and is situated in a medullary ray. This straight colle tubule now passes to the basal part of a renal pyramid, taking i

Fig. 528. —Diagram of the Uriniferous Tubules of the Kidney (Ki

a and a', outer and inner zones of cortex, which are free from

Malpighian bodies.

1. 1. Capsule of Bowman 4. 4. Spiral Tubule

2. 2. Neck of Capsule 5. 5. Descending Limb of Henle’s Loop

3. 3. First Convoluted Tubule 6 6. Loop of Henle

7. 7., 8. 8., 9. 9., Ascending Limb of Henle’s Loop

10. 10. Irregular Tubule 13. 14. Collecting Tubule

11. 11. Second Convoluted Tubule 15. Duct of Bellini

12. 12. Junctional Tubule

its course other junctional tubules from the labyrinth. In pa through the various parts of a renal pyramid the collecting tu unite at acute angles, and so become less numerous and at the same larger. They run in straight, slightly converging lines toward

THE ABDOMEN

903

x of a papilla, where they are very much reduced in numbers, but of (e size. In this final part of their course each collecting tubule ns the duct of Bellini. These excretory tubes open on the apex of ipilla, where there is often a foveola or small depression, and through se openings the urine escapes into a calyx.

The diameter of the ducts of Bellini is about inch.

Summary of a Tubule from Beginning to End.

[. The capsule of Bowman, containing a glomerulus in the labyrinth .

>. The neck, in the labyrinth.

5. The first convoluted tubule, in the labyrinth. j.. The spiral tubule, in a medullary ray.

5. The descending limb of Henle’s loop (small), in a basal part, and in part papillary zone, of a renal pyramid.

). The loop of Henle, in a papillary zone.

7. The ascending limb of Henle’s loop (large), in part of a papillary zone, a l part, and the cortex, in which latter it is in a medullary ray.

The irregular or zigzag tubule, in the labyrinth.

). The second convoluted tubule, in the labyrinth.

o. The junctional tubule, in the labyrinth on its way to a medullary ray.

[i. The collecting tubule, in a medullary ray of the cortex, and in a basal part renal pyramid.

[2. The duct of Bellini, in a papillary zone of a renal pyramid.

Structure of the Uriniferous Tubules. —The tubules are composed of a baset membrane lined with a single layer of epithelial cells. The basement ibrane itself consists of flattened epithelial cells. The tubules vary in but their average diameter may be stated as inch. The characters he lining epithelial cells present differences in the different tubules, which now be considered in order.

[. The capsule of Bowman is lined with a single layer of flattened epithelium,

h is reflected over the glomerulus, where it is more distinct in early life than

ie adult.

-• The neck is lined with cubical epithelium.

5. The first convoluted tubule is also lined with cubical epithelium, but the cells,

h are thick, are peculiar. The inner part of each cell—that is, the part next

lumen of the tubule—including the spherical nucleus, has granular protoplasm, st the outer part—that is, the part next the basement membrane—has its pplasm striated or fibrillated, owing to the presence of rod-shaped fibrils disposed ically to the basement membrane (Heidenhain). These fibrillated cells are dded laterally with processes by which they embrace one another. The en of the tubule is distinct.

p The spiral tubule is lined with epithelium similar ’to that of the first* conned tubule, and its lumen is distinct.

5- The descending limb of Henle’s loop is lined with clear, thin, flattened cells. tubule, though narrow, has a distinct lumen.

5 . The loop of Henle is lined with epithelium which resembles that of the lending limb.

7- The ascending limb of Henle’s loop is lined with fibrillated, cubical epithelial like those of the first convoluted and spiral tubules. Though it is of comffively large size, its lumen is small.

3 - The irregular or zigzag tubule is lined with cubical epithelial cells, which markedly fibrillated, and its lumen is minute.

3 - The second convoluted tubule is lined with epithelium which resembles t of the first convoluted tubule, with the following differences: (a) the cells longer; and (b) they are highly refractive. In size it corresponds with the ' convoluted tubule.

9o 4 A MANUAL OF ANATOMY

10. The junctional tubule is lined with clear, flattened, cubical epithelial , and its lumen is large.

11. The collecting tubule is lined with epithelial cells, which in its earlier are clear and cubical, but in its later part they are columnar, and the lum< very distinct.

12. The duct of Bellini is lined with epithelial cells which are clear

columnar.

Medullary Rays or Pyramids of Ferrein. —These take the torn pyramidal bundles of uriniferous tubules, which are separated f: each other by portions of the labyrinth. The tubules are straij and emerge from the basal parts of the pyramids. As these medul] rays are followed from the basal parts to the periphery, each gradu diminishes in breadth, and ultimately tapers to a point, which si a short distance from the fibrous capsule, being separated from it a portion of the labyrinth. The rays are thus conical, their bases b( at the basal parts of the renal pyramids, and their apices near the fibi capsule—hence the name ‘ pyramids.’ The explanation of this sh is that the tubules at the circumference of a medullary ray enter labyrinth sooner than those in the centre, which latter form the a of the ray.

Summary of a Medullary Ray. —Each contains the following tubules: (i) sj tubules; (2) ascending limbs of Henle’s loops; and (3) collecting tubules.

Medulla of the Kidney. —The medullary portion has been alre; generally described. It is composed of renal pyramids, consisl of uriniferous tubules and bloodvessels (true and false).

The tubules in the various parts of the renal pyramids are as folio

1. Basal Part. —This contains the following tubules:

Portions of the descending limbs of Henle’s loops.

Portions of the ascending limbs of Henle’s loops.

Collecting tubules.

2. Papillary Zone. —This contains the following tubules:

Portions of the descending limbs of Henle’s loops.

The loops of Henle.

Portions of the ascending limbs of Henle’s loops.

The ducts of Bellini.

3. Apex of the Papillary Zone. —This contains only the ducts Bellini.

Bloodvessels of the Kidneys — Arteries. —Each kidney receives large amount of blood from the renal artery, which is a branch of abdominal aorta. This vessel, as it approaches the hilum, divides i] four or five branches, which enter the sinus, where they are embedc in fat along with the calyces. They then subdivide into interlo' branches, which pass between the renal pyramids, where they contir to subdivide. On arriving at the junction of the cortex and bound; zone they form a series of arches, which are independent of one anotb and are called the cortico-medullary arches. Alongside of these th< are venous arches, which, unlike the arterial arches, anastomose fre<

THE ABDOMEN

905

ith one another. The convexities of the incomplete arterial arches

e directed towards the cortex, and the concavities towards the renal

yramids. The branches of the arches are interlobular and arteriae

ctae.

The interlobular arteries (cortical) arise from the convexities of the rches and enter the labyrinth of the cortex, in which they pass outards between the medullary rays, hey give off afferent and capsular ranches.

The afferent branches are so named ecause they carry blood to the 'omeruli. They arise from the in^rlobular arteries at frequent interals, and each passes to a capsule f Bowman without giving off any ranch. Having pierced the capsule t one pole, the afferent vessel breaks p into a number of convoluted ipillary vessels, which form a small ascular ball, called a glomerulus Malpighian corpuscle). The blood is onveyed away from the glomerulus y an efferent vessel, which is variously sgarded as an artery and a vein, his efferent vessel is smaller than tie afferent artery. It pierces bowman’s capsule at the same pole s the afferent artery, but separate

om, though close to, it. Therefter it breaks up into a network of

apillary vessels, which invest the orresponding first convoluted urinierous tubule, the meshes of the network being polygonal. The efferent r essels of those glomeruli which lie learest to the renal pyramids are iisposed in a different manner. They >reak up into bundles of straight vessels, called false vasa recta, which nter the basal parts of the pyramids, diere they supply to a large extent the uriniferous tubules, upon the mils of which they form capillary networks with elongated meshes, t is, however, to be noted that the renal pyramids also receive true irterise rectae from the cortico-medullary arterial arches.

The Glomerulus (Malpighian Corpuscle). —A glomerulus of the kidney s a small ball of convoluted capillary bloodvessels, having two vessels connected with it, one of which is an afferent artery and the other an 'fferent vessel. The vessels of many of the glomeruli are collected into

VESSELS OF THE KlDNEY.

A, cortex; B, medulla.

1. Arterial Arch

2. Interlobular Artery

3. Afferent Artery of Glomerulus

4. Capsular Branches

5. Efferent Vessel of Glomerulus

6. Glomerulus

7. First Convoluted Tubule

8. True Arteria Recta

9. False Arteria Recta

10. Venous Arch

11. Interlobular Vein

12. Venae Stellatae

13. Venae Rectae

9o6 A MANUAL OF ANATOMY

bundles, an arrangement which renders these glomeruli tabulated, number of lobules varying from two to five. Each glomerulus within a capsule of Bowman, and the flattened epithelium of the caps is reflected over the glomerulus from the points of entrance and exil the afferent and efferent vessels. The epithelial cells covering the c puscle are thicker and less flattened than those lining the capsule Bowman, and are better marked in early life than in the adult, the case of the tabulated glomeruli the epithelial investment dips between the component lobules. The epithelium of Bowman’s caps and the epithelium of the glomerulus, which in each case forms a sin layer, are separated from one another by a slight interspace. 1

diameter of a glomerulus is about ¥ To * n The glomeruli are confined to the cortex of i kidney, where they lie in rows in the labyrii between the medullary rays. There is a narr zone immediately within the external capsi and another narrow zone close to the re: pyramids, from both of which glomeruli ; absent.

The capsular branches of the interlobu arteries supply the external fibrous capsule the kidney, in which they anastomose w: branches of the lumbar arteries from the c dominal aorta.

The arteriae rectae (medullary), or vasa rec (true), arise from the concavities of the corti( medullary arterial arches, and at once enter t basal parts of the renal pyramids. Here th break up into bundles of straight, sligh diverging arterioles, which run between t bundles of straight, slightly converging uri: ferous tubules, a mutual arrangement whi imparts to the renal pyramids a longitudina striated appearance. The capillary networ formed by these arterioles have necessar: elongated meshes. It is to be noted that t renal pyramids derive their blood-supply frc two sources—namely, (i) the arteriae rectae, or vasa recta (true), frc the cortico-medullary arterial arches; and (2) the false vasa recta frc the efferent vessels of those glomeruli which lie nearest the rer pyramids. It is also to be noted that a glomerulus of the kidney is ball of convoluted capillary bloodvessels, which is enclosed with a capsule of Bowman, whereas a Malpighian body of the spleen is collection of lymphoid or adenoid tissue which is a localized expansi< of the external or lymphoid coat of the small arteries in the interi of that organ.

Veins — Veins of the Cortex. —These are called the interlobular vein Some of them commence on the surface of the kidney beneath tl

showing a Glomerulus OF THE Kidney with its Afferent and Efferent Vessels, and a Proximal Convoluted Tubule with ITS Venous Plexus (Bowman).

1. Glomerulus

2. Bowman’s Capsule

3. Uriniferous Tubule

4. Interlobular Artery

5. Afferent Vessel

6. Efferent Vessel

7. Venous Plexus around

Tubule

8. Interlobular Vein

THE ABDOMEN

907

psule, from which they return blood, and these are called vence stellatce, cause the venous radicles which give rise to them converge to a int, and so present a star-like appearance. Others originate in the sxuses around the uriniferous tubules. The interlobular veins rminate by joining the convexities of the venous arches, which are uated between the cortex and the renal pyramids.

Veins of the Medulla. —The veins of the renal pyramids commence plexuses which surround the ducts of Bellini in the apical parts of the pillary zones, and they are called vencB rectcB. As these traverse the aamids they are collected into bundles of straight vessels, which ien into the concavities of the cortico-medullary venous arches.

Cortico-medullary Venous Arches. —These arches, which are comste, are situated between the cortex and the renal pyramids, where ey lie alongside of the incomplete arterial arches. They derive their Dod from the interlobular veins of the cortex and the venae rectae the renal pyramids. The veins which proceed from these arches „ss between the pyramids to the sinus of the kidney, where they Lite to form the renal vein, which terminates in the inferior vena cava. Lymphatics. —These consist of two groups, superficial and deep, le superficial lymphatics, which are few in number, form a plexus in e fibrous capsule, and communicate with lymph spaces between the iniferous tubules in the outer part of the cortex. They terminate r joining the deep lymphatics at the hilum. The deep lymphatics company the bloodvessels, and communicate with lymph spaces itween the uriniferous tubules of the cortex and boundary zone, n emerging at the hilum they receive the superficial lymphatics, id then pass to the juxta-aortic group of lumbar glands.

Nerves. —The kidney receives numerous nerves from the renal exus, which derives its fibres from (1) the aortico-renal ganglion, which the lesser splanchnic nerve terminates; (2) the coeliac plexus; id (3) the aortic plexus. If there is a lowest splanchnic nerve present reinforces the renal plexus. The nerve-fibres are partly sympathetic, irtly spinal through the lesser and lowest splanchnic nerves, and in irt derived from the right vagus through the coeliac plexus. I hey ^company the arterial branches, and ramify upon the walls of the sssels and uriniferous tubules.

Excretory Apparatus of the Kidney. —This consists of the calyces,

elvis, and ureter.

Ureter. —This is the excretory duct of the kidney, and it has the >rm of a cylindrical tube, like a goose-quill, its colour being a dull hite. Its length varies from 12 to 16 inches, and its diameter is bout 1 inch. At its lower extremity it opens into the bladder, and t the hilum of the kidney it joins the pelvis of the kidney, which is mnel-shaped, being wide above and narrow below. Ihe pelvis is attened from before backwards, and lies partly in the sinus and artly outside the hilum, its direction being downwards and inwards, t is formed by the union of two or three primary divisions or greater alyces (infundibula) within the sinus, and these again are formed by

9o8

A MANUAL OF ANATOMY

the union of about nine secondary divisions, called lesser calyces. 1 number of lesser calyces thus usually falls short of the number of re pyramids (8 to 18), the explanation being that one lesser calyx n grasp two papillae or even three. The lesser calyces embrace i papillae of the renal pyramids, which thus project into them, and tl receive the urine as it oozes through the pores on the apices of 1 papillae, these pores being the openings of the ducts of Bellini. 1 interspaces between the lesser calyces in the renal sinus are occup; by the branches of the renal bloodvessels and by fat.

Structure of the Ureter. —The ureter is a thick-walled muscu tube, lined with mucous membrane, and consists of three coats external or fibrous, middle or muscular, and internal or muco’

Middle Circular Muscular Fibres

Outer Longitudinal Muscular Fibres

53 1 • Transverse Section of the Lower Part of the Ureter, showing its Minute Structure.

The fibrous coat is composed of fibrous tissue, very compactly arrange^ and contains the bloodvessels and nerves, which here subdivide. Tl muscular coat is composed of plain muscular tissue, which is dispose in three layers —outer longitudinal, middle circular, and internal long tudinal. The outer longitudinal layer is best marked in the lower ha of the ureter, where it forms a continuous investment. In the uppf half of the tube its bundles are somewhat scattered. The mucoi coat superiorly is continued over the papillae of the renal pyramids, an interiorly becomes continuous with the mucous membrane of tb bladder. It is covered by stratified transitional epithelium, the celbeing arranged in four layers. In the most superficial layer (nearer the lumen of the tube) the cells are cubical, and present depressions o

THE ABDOMEN

909

eir deep surfaces, which receive the round ends of the pyriform cells the layer beneath. In the second layer the cells are pyriform, the und superficial ends being capped by the cubical cells of the first ^er, and the narrow deep ends projecting between the deeper cells, the third and fourth layers the cells are round or oval. The mucous smbrane is thrown into longitudinal folds, and the lumen of the be, which is of small size, presents under the microscope a branched •pearance on cross-section.

Around the lower end of the ureter for a distance of 3 or 4 mm. a fibrous-tissue covering known as Waldeyer’s sheath. Between is sheath and the ureteral wall proper is some loose bursal tissue, lich serves to facilitate the slight but important movement which kes place between the lower end of the ureter and the vesical wall contraction and relaxation of the bladder, and which has for its irpose the prevention of regurgitation of urine.

Blood-supply—Arteries. —The ureter receives branches from the nal, testicular (ovarian in the female), common iliac, and superior

sical arteries.

The veins terminate in the vessels corresponding to these arteries. Lymphatics. —These pass to the juxta-aortic group of lumbar glands , Ld to the internal iliac glands.

Nerves. —These accompany the arteries, and are derived from e renal, testicular (ovarian in the female), and pelvic plexuses. The )res form plexuses in the fibrous and muscular coats, which contain lall ganglia.

Structure of the Pelvis and Calyces. —The structure of these parts the excretory apparatus resembles that of the ureter, with the

ception that they have only two layers of plain muscular tissue,

stead of three as in the ureter. The layer which is wanting is the tier longitudinal layer. The lesser calyces are attached to the bases the papillae, and in these situations their fibrous coats become coniuous with that part of the fibrous capsule of the kidney which is 'olonged inwards through the hilum to line the sinus. The internal ngitudinal muscular fibres disappear towards the papilla, but the rcular muscular fibres accompany a lesser calyx to its termination, here they are arranged in the form of a circular band, which surrounds base of a papilla at the line of attachment of a calyx. The stratified ansitional epithelium of the mucous coat of a lesser calyx is pronged over the apex of each papilla.

Stroma of the Kidneys. —Between the uriniferous tubules and oodvessels there is a certain amount of connective tissue, which present in greatest abundance in the region of the papillary zones, his constitutes what is known as the fibrous or intestinal stroma, which there is a very small amount.

Early Condition of the Kidneys. —The kidneys of a child at the period of birth e lobulated, each lobule representing a renal pyramid surrounded by cortical bstance. In this respect they resemble the permanently lobulated kidneys of rtain animals— e.g., the ox. The lobules first become apparent towards the

9io

A MANUAL OF ANATOMY

end of the third month of intra-uterine life, and all traces of them have usi

disappeared by the eighth or tenth year.

Fig. 532. —-Kidney of a Child shortly before Birth.

They may, however, remain persh to a greater or less extent throug life, though this condition is of rare occurrence. It is, however, uncommon to find the surface o adult kidney marked by faint gro indicative of its original lobul condition. The disappearance of lobulated condition is brought a’ by the adjacent lobules coalescing, being accompanied by an incre development of cortical substanc the surface. The portions of cor substance which remain in the sp between the renal pyramids (ex their apical parts) form the r columns.

Development of the Kidney and Ureter.

The metanephros, or permanent kidney, is the last of the serie: excretory organs formed in the human embryo. For the acco of these organs, see p. 94 et seq.

The ureteric bud, the earliest formation in association with metanephros, begins to grow from the mesonephric duct when embryo is about 5 mm. long. It is a club-shaped, hollow outgrow which (Fig. 533) is surmounted from an early stage by a blastemal c formed by metanephric mesoderm. The markedly condensed d or inner layer of this cap is a very noticeable feature. The hoi outgrowth elongates fairly rapidly, growing in a cranial directi dorsal to the mesonephros, and carrying its blastemal cap on extremity as it grows. The bulbous end soon divides into two, c from these secondary outgrowths take place, each process carrying own blastemal cap upon it. In this way the cavities of the gret and lesser calyces are marked out. The process continues of elongat of outgrowth, subdivision, and consequent new outgrowths, and so and thus the collecting tubes of the kidney are made, each advanc end being covered by its metanephric cap of blastemal tissue.

At a later stage the earliest formed generations of these collecting-t systems are taken up into the calyces, so that the final number of collecting tu is not the same as the whole number formed, and more tubes come to open i the calyces directly than originally grew from them.

the formation of outgrowths goes on during the second, thi and fourth months, and probably for a considerable time after tl About the beginning of the third month, however, some of the tul subdivisions have reached their terminal stages, and the blasten caps of these terminal outgrowths begin to show activities whi ultimately lead to the formation of the secretory parts of the tubi system. 1 he inner zone of the cap forms a solid mass of cells, whi

THE ABDOMEN

911

>n becomes hollow, and is termed the renal vesicle. A curved short mle grows from this towards the bent end of the terminal collecting >e, with which it becomes connected. The renal vesicle is in the antime invaginated, and thus constitutes a glomerulus. The short ■ved tubule, somewhat in the shape of an S, elongates slowly. The

Fig. 533. —Schematic Drawings to illustrate the Formation of the Tubular System of the Kidneys.

A the ureteric outgrowth is shown arising from the mesonephric duct close to where this enters the cloaca. The enlarged end of the bud is covered by its blastemal cap. The enlarged end becomes bilobed. B, each lobe covered by its cap. Further subdivisions are seen in C. Terminal subdivisions are shown in D, where the cap is forming, on the left, a rounded ‘ renal vesicle/ R.V. On the right a tubule is growing from the vesicle toward the end of the collecting terminal. In E and F the tubule has fused with the terminal, and by elongating is making convoluted tubules and a loop of Henle. A vascular loop V grows against the renal vesicle and the adjoining part of its tubule, and invaginates them, producing a glomerulus.

'ond convoluted tubule is formed from the upper limb of the curve, s first convoluted tubule from its lower limb, and the intervening rtion is lengthened into Henle’s loop. Henle’s loops can be disL °tly recognized during the fourth month. The other descriptive rts of the system of tubules are gradually formed as elongation pn> isses.

912

A MANUAL OF ANATOMY

It is seen, then, that the tubule system, from the glomerulus to i arched collecting duct, is derived from the metanephric mesodei while the whole system of collecting ducts is formed by outgrov from the original ureteric growth. The junction between the t parts of the whole tubule system is effected shortly after the blaster tubule begins its growth; it is the failure of this junction which ir lead to one of the varieties of congenital cystic kidney.

The secondary junction between outgrowths from the mesonephric duct on one hand, and tubules formed separately in the mesoderm on the other ha is not in itself an extraordinary or out-of-the-way occurrence. It is well knc to occur in several species of animals, and it is apparently represented in development of the secondary tubules of the human mesonephros, which, wl

Suprarenal Glands

Fig. 534. —The Mesonephro, Mesonephric, and Para-mesonephric Due

and Contiguous Parts (Allen Thomson).

they are formed, extend toward the mesonephric duct, and meet secondary p jections from this duct in their direction. In the case of the metanephros t may, in the light of what has just been said, be looked on as corresponding w these secondary tubules of the mesonephros coming into relation with enormou elongated outgrowths from the mesonephric duct.

The vascular constituents, the interstitial connective-tissue stroma, renal columns, and the renal capsule are developed from the metanephric blaster

The ureter of either side, which originally opens into the uro-genital sii in common with the mesonephric duct, becomes detached from that duct a opens by an independent orifice into the uro-genital sinus on its dorsal aspe It may here be stated that the urinary bladder is developed from the u genital sinus.

Summary. —The pronephros is functional in lower vertebrates— e.g., cert; Fishes, and Amphibia during the larval stage. In Man it is rudimentary, d pronephric duct persists as the mesonephric duct.

THE ABDOMEN

913

Pronephros'

Diaphragmatic - Ligament of Pri/nit/t/e /t/cfney

Mesoneph . ' M( sorter hr Duct

Duct of Epoophoron

Prostatic

Utricle

6/rooep/fai S/pus fi/est/pp/e)

535 -—Development of the Uro-genital System (after Heisle).

58

914

A MANUAL OF ANATOMY

The mesonephros or Wolffian body succeeds to the pronephros, and pe as the functional kidney in Fishes and Amphibia. In Man it atrophies large extent, and is replaced by the metanephros.

The metanephros is the permanent human kidney.

THE PELVIS.

The pelvis is the lower division of the abdomen which lies b the level of the pectineal lines and sacral promontory. Unlike abdomen proper, the walls of the pelvis are chiefly osseous, posterior wall is constructed by the sacrum and coccyx, with the ori of the pyrif ormes muscles. Each lateral wall is formed by the body spine of the ischium, and is covered by the obturator internus mu

Pelvic Colon Gt. Omentum

Fig. 536. —Transverse Section at Level of Lumbo-sacral Junction

(after Symington).

The anterior wall is formed by the bodies of the pubic bones, whicJ the median line construct the symphysis pubis. Between the poste: wall and each lateral wall is a large space, which is partly closed by powerful sacro-tuberous and sacro-spinous ligaments. This spact divided into two parts by the sacro-spinous ligament and the spin( the ischium. The upper part forms the greater sciatic foramen, wb transmits the pyrif ormis muscle; the superior gluteal vessels, lymphat and nerves; the inferior gluteal vessels, lymphatics, sciatic nerve, < posterior cutaneous nerve of thigh; the internal pudendal vessels c lymphatics and pudendal nerve; the nerve to the obturator inter] and gemellus superior; and the nerve to the quadratus femoris c gemellus inferior. The lower part forms the lesser sciatic foram which transmits the obturator internus muscle and its nerve, 1

THE ABDOMEN

915

rnal pudendal vessels, and the pudendal nerve. At each lateral t of the anterior wall is the obturator foramen, which is closed, -pt superiorly, by the obturator membrane, covered by the obturator rnus muscle. Below the symphysis pubis is the pubic arch, which •ccupied by the perineal membrane. The pelvic wall, thus conicted, is clothed by the pelvic fascia. Superiorly the pelvic cavity uite open and in free communication with the abdomen proper, jrioily it is for the most part closed, a complex septum separating rom the perineum underneath. This septum is partly muscular partly fascial. The muscles entering into it are the levatores ani the coccygei, which construct the pelvic diaphragm. The fascial rent is formed on either side by the visceral pelvic fascia, which hes the superior or pelvic surface of the muscular diaphragm, and the anal fascia, which covers its inferior or perineal surface. The

Fig. 537. —Male Pelvic Region seen from Above.

r of the pelvis is consequently movable, being capable of ascending descending. It affords passage to the rectum and urethra, and, in ition, in the female to the vagina.

Contents of the Pelvis. —The contents of the male pelvis are as

)ws: the pelvic colon and rectum; the bladder, with the lower tions of the ureters and the prostate gland, the latter containing prostatic part of the urethra; the seminal vesicles and the lower tions of the vasa deferentia; the internal iliac vessels and their fiches; portions of the superior rectal and median sacral vessels; rectal, vesical, and prostatic venous plexuses, the latter receiving dorsal vein of the penis in two divisions; the sacral and coccygeal uises and their branches; the pelvic portions of the gangliated ip a thetic trunks; and the obturator nerves in part of their course. The differences in the contents of the female pelvis, as compared h those of the male, are as follows:

A MANUAL OF ANATOMY

916

For the prostate gland and prostatic portion of the urethra sul tute the female urethra, uterus, and vagina. For the seminal vesi and portions of the vasa deferentia substitute the broad ligament the uterus and their contents—namely, the uterine tubes, the ova with their ligaments, and the ligamenta teres of the uterus. Ad< portions of the superior rectal and median sacral vessels portions of ovarian vessels. For the prostatic venous plexus substitute the pu< dal plexus, and add the uterine and ovarian venous plexuses.

THE MALE PELVIS.

General Position of the Viscera. —The pelvic colon and reel are situated upon the posterior wall, the pelvic colon reaching as lo\ the third sacral vertebra, and the rectum extending thence downwa

Comm. Iliac a. 1 ** 11 **** 1

Ureter- •

Lumbo-sacral Trunk Ext. Iliac A.

Obtur. N

Sup. Ves. A

Obtur. A

Vas Def Lat. Umbil. Lig.

Fig. 538. —Structures on Side Wall of Male Pelvis.

and forwards to the interval between the levatores ani muscles, wh< it is succeeded by the anal canal. The bladder is anterior in positi< being situated behind the bodies of the pubic bones, and resting by base upon the rectum. The seminal vesicles and the lower portions

THE ABDOMEN

917

vasa deferentia lie in contact with the base of the bladder, between nd the rectum. The prostate gland surrounds the prostatic part he urethra.

Peritoneum. —The disposition of the peritoneum will be simplified iefining the limits of the pelvic colon and rectum, and the different ts of the bladder. The pelvic colon extends from the inner border he left psoas major, just anterior to the left sacro-iliac articulation, he level of the third sacral vertebra. The rectum extends from the d sacral vertebra to a point t\ inches in front of and below the tip he coccyx, where it pierces the pelvic diaphragm to terminate in anal canal, which is the part of the large gut surrounded by the incter muscles. The bladder, when empty, presents the following ts: (1) an apex, which is directed forwards, and lies behind the upper

Pelvic Colon

i

/

Line of Peritoneal Reflection Ureter

t- Vas Deferens

Seminal Vesicle Bladder

/ Urachus

Symphysis Pubis

Levator Ani (cut) /

Anus

Corpus Cavernosum , Corpus Spongiosum Bulb and Bulbo-spongiosus ' Deep Layer of Sup. Perineal Fascia » Perineal Pouch Membranous Urethra Bulbo-urethral Gland Prostate Gland and Capsule

Perineal Membrane

Fig. 539.— The Viscera of the Male Pelvis (Lateral View).

of the symphysis pubis, where it has connected with it the median

rilical ligament lepresenting the urachus; (2) a fundus (base) or terior surface, directed backwards and downwards towards the ■um, from which it is separated by the seminal vesicles and vasa irentia; and (3) a body which has a superior and two infero-lateral aces. Four borders are described, two being lateral, and serving separate the superior and infero-lateral surfaces; one posterior, mating the fundus from the superior surface, and stretching between two ureters as they pierce the bladder wall; and one faintly marked mior border, which separates the two infero-lateral surfaces. The

er enters the bladder at the junction of the fundus with the superior

infero-lateral surfaces at what is known as the lateral angle.

The peritoneum, having descended from the posterior wall of the omen over the common iliac vessels, enters the back part of the

918

A MANUAL OF ANATOMY

pelvic cavity, where it invests the pelvic colon, forming behind il expanded, wavy mesentery, called the pelvic meso-colon, which attac it to the front of the sacrum as low as the third sacral vertebra. ' peritoneum is then prolonged upon the rectum, the upper third of wl it covers anteriorly and laterally , but not posteriorly, the middle t! being covered by it only anteriorly , whilst the lower third is destil of peritoneal covering. The point at which the peritoneum leaves rectum is fully 3 inches above the anus. The membrane is now can forwards to the upper ends of the seminal vesicles and the adjac portions of the vasa deferentia, which it covers. It then pa: forwards over the superior surface of the bladder, which it comple

Pelvic Colon Bladder

Fig. 540. —Transverse Section through the Second Sacral Vertebr

(after Symington).

covers as far as the apex. Here it meets the median umbilical ligame and by this is conducted from the bladder to the posterior surface the anterior abdominal wall. Along each lateral border of the blad< the peritoneum is reflected over the corresponding lateral wall of 1 pelvis. In passing from the rectum to the upper part of the base the bladder the peritoneum forms the recto-vesical pouch. The both of this pouch is, as a rule, fully 1 inch distant from the base of 1 prostate gland, thus leaving the part of the base of the bladder, cat the external trigone, quite free from peritoneum. The peritoneum, it passes to and from the bladder, forms certain folds, which constiti the false ligaments of the viscus. These are five in number as follow

THE ABDOMEN

919

posterior , which represent the laterally-disposed lips of the mouth

he recto-vesical pouch; two lateral, right and left, which represent

reflection of peritoneum from each lateral border of the bladder the corresponding lateral wall of the pelvis; and superior, which he reflection of the peritoneum from the apex of the bladder to posterior surface of the anterior abdominal wall along the median bilical ligament. The parts of the bladder which are left uncovered peritoneum are (1) the inferior surface, and (2) the external trigone.

The pelvic peritoneum on either side of the bladder and rectum presents recesses when these viscera are moderately distended, which are named, a before backwards, paravesical and pararectal.

Retro-pubic Cellular Tissue. —This is a collection of areolar and pose tissues which lies between the posterior aspect of the bodies

he pubic bones, the bladder, and medial pubo-prostatic ligaments.

Pelvic Fascia. —This fascia clothes the inner wall of the pelvis, and lishes inward expansions, which have an intricate connection with,

Parietal Pelvic Fascia

Visceral Pelvic Fascia Levator Ani Anal Fascia Obturator Internus Parietal Pelvic Fascia

i | v —*

Prostate Gland, with Urethra Pudendal Canal..

Fig. 541.—The Pelvic Fascia (Anterior View).

1 serve to support, the contained viscera. It is divisible into two 'tions—parietal and visceral.

Parietal Portion .—Over the posterior wall of the pelvic cavity

parietal portion of the pelvic fascia, which is here very thin, covers

1 intrapelvic portion of each pyriformis muscle and the corresponding ral plexus, this portion being known as the fascia of the pyriformis. er the lateral wall the fascia attains considerable strength, and is ached superiorly to the back part of the iliac portion of the pectineal 3 for a short distance, where it becomes continuous with the iliac cia. In front of this the fascia falls short of the pectineal line, and ixed to the lateral wall of the pelvis a little below the line, its attachnt being oblique, and accurately following the upper border of the turator internus muscle. When it arrives at the upper part of the turator foramen there is a break in the osseous attachment of the cia, which here joins the upper border of the obturator membrane sr the upper border of the obturator internus, and so converts the turator groove into a canal for the passage of the obturator vessels

920

A MANUAL OF ANATOMY

and nerve. At the upper and inner part of the obturator foramen fascia resumes its osseous attachment, but falls more and more st of the pelvic margin, its connection with the back of the body of os pubis being in a direction downwards and inwards till it reac a point just below the lower part of the symphysis pubis. The fas descends from the foregoing line of attachment, closely covering obturator internus, to be attached as follows from before backwar (i) to the pelvic aspect of the ischio-pubic ramus near the pubic ar medial to the obturator internus; (2) to the inner margin of the falcifc process of the sacro-tuberous ligament at the lower part of the iscl ramus, and also to the sacro-tuberous ligament itself, where thai attached to the inner margin of the ischial tuberosity; and (3) t< portion of the sacro-tuberous ligament near its ischial attachment, e to the anterior margin of the greater sciatic notch The lateral port of the parietal pelvic fascia, from its relation to the obturator inten

Parietal Pelvic Fascia

Levator Ani..

Anal Fascia

Obturator Internus..-N$!/ Parietal Pelvic Fascia-

Pudendal Canal

Visceral Pelvic Fascia

--- Seminal Vesicle

Vas Deferens

h J G. 542. —Diagram of the Pelvic Fascia from Behind.

muscle, is sometimes called the obturator fascia. From its lower attac ment the fascia is continued backwards and inwards over the great sciatic foramen, pyriformis, and sacral plexus to the sacrum, as t. fascia of the pyriformis. As it covers the foramen it is perforated 1 the superior and inferior gluteal, and internal pudendal vessels, and m consequence indistinct.

At the anterior part of the pelvic cavity the fascia, after takii attachment to the pelvic surface of the ischio-pubic ramus near t] pubic arch, is continued inwards over that arch, where it lies behii the sphincter urethrae muscle, and forms one half of the superior lay ot the perineal membrane, the other half being formed by the corr spondmg portion of the fascia of the opposite side. When it arrives ; the urethra it changes its course, and passes backwards over the anterii border of the levator ani to blend with that portion of the visceral pelv fascia which ensheathes the prostate gland.

THE ABDOMEN

921

In the direction of a line passing from the inner aspect of the ischial ine to the back of the body of the os pubis, near its lower end and close the symphysis, the lateral pelvic fascia is strengthened by fibres dch impart to it a white colour. This part is called the arcus tenleus [white line), and it serves to divide the fascia into two portions— per or pelvic proper, and lower or perineal. The pelvic portion )ks into the pelvic cavity, and covers the upper part of the obturator

ernus, whilst it is itself covered by the peritoneum. The perineal

rtion covers the lower part of the obturator internus, and lies on the ter wall of the ischio-rectal fossa, where it constructs the pudendal rial. The under aspect of the arcus tendineus affords extensive [gin to the levator ani muscle.

Visceral Portion of the Pelvic Fascia. —The visceral portion is stined to support the lower part of the bladder, seminal vesicles, rminal portions of the vasa deferentia, prostate gland, and rectum, is a laminar offshoot of the parietal portion, from which it springs mg the arcus tendineus. Though, however, this is its principal urce, it has an independent origin anteriorly on either side of the ddle line from the posterior aspect of the body of the os pubis near e lower part of the symphysis. In this latter situation it lies a little ove the attachment of the parietal portion, the anterior fibres of the rator ani taking origin from the portion of bone between the two seise. Though the visceral portion forms one continuous sheet along pelvic attachment, its ultimate disposition is so intricate that it is nvenient to consider its arrangement under three divisions.

1. Opposite the bladder, seminal vesicle, and rectum. In this region e visceral portion of the fascia passes inwards as far as the outer rder of the seminal vesicle. In doing so it covers the upper surfaces of e levator ani and coccgyeus, and is in turn covered by the peritoneum.

the outer border of the seminal vesicle it divides into three laminae—'per, middle, and lower. The upper or vesical lamina ascends upon e lateral aspect of the bladder for a short distance, and ultimately >es itself in the muscular tissue of the vesical wall. This portion at ch side forms the lateral pubo-prostatic ligament of the bladder. The ddle or recto-vesical lamina passes inwards between the base of the idder and the rectum, and is continuous with the corresponding nina of the opposite side. As it passes inwards it furnishes a sheath the seminal vesicle and adjacent portion of the vas deferens, closely 'apping these structures to the base of the bladder. The lower or 3tal lamina descends upon the side of the rectum, and passes to its sterior surface, where it is continuous with the rectal lamina of the posite side.

2. Opposite the lateral aspect of the prostate gland. I11 this situa>n the visceral portion of the fascia also divides into three laminae upper, middle, and lower. The upper or prostatic lamina passes vards over the anterior surface of the prostate gland, and is congous with the prostatic lamina of the opposite side. The middle recto-prostatic lamina passes inwards between the posterior surface

922

A MANUAL OF ANATOMY

of the prostate gland and the rectum, and is continuous with corresponding lamina of the opposite side. The lower or rectal lam is unaltered in its disposition. The upper or prostatic and middle recto-prostatic laminse furnish a stout sheath to the prostate gland.

3. Between the pubic bodies and the anterior aspect of the pros gland. The portion of the visceral fascia in this region represe the upper lamina in the other regions, and may be called the pu prostatic lamina. It is arranged in the form of two stout cords, wb are known as the medial pubo-prostatic ligaments or the anterior i ligaments of the bladder. Each is attached anteriorly to the poste] aspect of the body of the os pubis, near the lower part of the symphy and a little above the attachment of the parietal portion of the pe] fascia in this region, the anterior fibres of the levator ani taking ori from the portion of bone between the two fasciae. As the cord -1 fascial bands pass backwards they are connected by a portion of visceral fascia which covers the dorsal vein of the penis and lies deef thus giving rise to a small pouch, which is capable of admitting ■ point of a finger. This pouch is filled with fat, which is continuous w the retro-pubic pad of fat. The anterior portion of the visceral fas lies upon the anterior surface of the prostate gland, and on reach the bladder it passes forwards on its inferior surface, where it sc disappears in the muscular tissue of the vesical wall. The mec pubo-prostatic ligaments are largely composed of plain muscular tiss which is derived from the longitudinal fibres on the inferior surface the bladder as they pass to take attachment to the back of the bod of the pubic bones on either side of the middle line. These fib constitute the so-called pubo-vesical muscles.

Anal Fascia. —This very thin sheet of fascia is an offshoot fr< the parietal pelvic fascia just below the white line and the origin the levator ani. It closely covers the ischio-rectal surface of tl muscle and of the coccygeus, upon which it descends to the region the anus, where it blends with the aponeurotic investment of t sphincter ani externus.

Sympathetic Plexuses in the Pelvis. —These are derived from t hypogastric plexus, which is formed by the fusion of the two latei strands of the aortic plexus after they have crossed the common ili arteries. It is reinforced by branches from the ganglia of the lumb sympathetic trunks, and is situated in front of the body of the fif lumbar vertebra between the common iliac vessels. It is a lar£ flattened plexus, measuring about ij inches in breadth, and breaks 1 into two divisions, which form the right and left pelvic plexuses. Ea< of these enters the pelvis on the inner side of the internal iliac arte and takes up a position on the side of the rectum. The pelvic plexi of each side is reinforced by branches from the upper one or two gangl of the pelvic sympathetic trunk, and by spinal fibres from the anter! primary divisions of the third and fourth sacral nerves (sometimes at the second), there being very small ganglia at the places of junctio From each plexus the following secondary plexuses are given off, whic

THE ABDOMEN

923

xompany the corresponding branches of the internal iliac artery: aemorrhoidal, vesical, and prostatic, the latter being replaced in the male by the vaginal and uterine plexuses.

Internal Iliac Artery. —This vessel arises from the common iliac Dposite the sacro-iliac joint at the level of the lumbo-sacral joint, id terminates opposite the upper border of the greater sciatic notch y.dividing into an anterior and a posterior division. The length of le vessel is about ij inches, and its direction is downwards and ickwards.

Relations — Anterior. —The artery is covered by the peritoneum, id the ureter descends over it. In front of the ureter are the ovary id the fimbriated extremity of the uterine tube. The terminal part i the ileum forms an anterior relation of the right vessel, whilst the dvic colon is similarly related to the left. Posterior. —The vessel ‘sts chiefly upon its own vein, but near its origin it is placed over the )mmencement of the common iliac vein. Behind the veins there are le lumbo-sacral trunk and sacro-iliac joint. Lateral. —The psoas tajor, with the intervention of the external iliac vein, and subsequently le lateral wall of the pelvis, with the intervention of the obturator srve. Medial. —The peritoneum.

Varieties. —The chief variety affects the length of the vessel. It may be lorter or longer than usual, according as the common iliac is longer or shorter lan normal, or according to the height at which the internal iliac ends in its vo divisions.

Foetal Condition. —During foetal life the internal iliac is represented by the mbilical artery, the size of which greatly exceeds that of the external iliac. The mction of this artery is to carry the impure blood from the foetus to the placenta

the mother. The umbilical artery passes forwards to the posterior surface of

le anterior wall of the abdomen, being crossed by the vas deferens. It then scends to the lower part of the umbilicus, where it leaves the abdomen with its llow. The two umbilical arteries, together with the umbilical vein, form the mbilical cord, in which the arteries describe spiral coils around the vein. The •teries convey the impure blood to the placenta, where it is purified, after which is returned to the abdomen of the foetus by the umbilical vein. After birth, lere being no further use for the placental circulation, the umbilical cord is tied, id the child separated from the mother. The umbilical arteries become imperious, and each is converted into a fibrous cord. The obliteration, however, does it involve the first i-J inches of the vessel, which persists as the internal iliac rtery of the adult. Moreover, the proximal end of the fibrous cord representing ie obliterated umbilical remains pervious also, and being connected with the iterior division of the internal iliac, it furnishes the superior vesical artery or "teries. This pervious portion lies along the side of the pelvis beneath the eritoneum, where it is crossed by the vas deferens in the male and the ligatentum teres of the uterus in the female. The foetal umbilical artery gives off ie inferior gluteal, which is the primitive main artery of the lower limb, until ie external iliac, which becomes the femoral, is developed.

Branches.—These are subject to much variation. In normal ases they arise from the two terminal divisions, anterior and posterior, xne of them being parietal in their distribution, which will be indicated y the letter P, whilst others are visceral, which will be indicated by he letter V. The branches are as follows:

924

A MANUAL OF ANATOMY

Anterior Division.

Visceral.

Umbilical (which gives off superior vesical). Inferior vesical.

Middle rectal.

Parietal.

Obturator.

Internal pudendal. Inferior gluteal.

Posterior Division

Parietal.

Uio-lumbar. Lateral sacral. Superior gluteal.

In the female the inferior vesical artery may be replaced by t vaginal, or the vaginal may be an independent branch; the uteri artery is always a special branch.

Lateral J Sacral \

„■ Left Common Iliac

Anterior Superioi Iliac Spine

Internal Iliac

_- Ilio-lumbar

_Posterior Division

_External Iliac

Anterior Division

c • rrp

Superior Gluteal

Inferior Gluteal

Sacro-spinous ^

Ligament A

Sacro-tuberous'

Ligament

Internal Pudendal'

Inferior Rectal

Umbilical - - - ' Inferior Vesical Deep Circumflex Iliac Inferior Epigastric

....Obturator Nerve

-Obturator Artery

Obturator Vein

.Obturator Membrane

....Symphysis Pubis

Superficial Perineal ‘

Transverse Perineal

Dorsal Artery of Penis Deep Artery of Penis

Artery of the Bulb

^ IG - 543 -—The Left Internal Iliac Artery and its Branches.

Anterior Division. — 1 he superior vesical artery (V) arises from th pervious portion of the fibrous cord which represents the fcetal umbilica artery, and at once breaks up into several twigs which frequently hav independent origins. They are distributed to the upper portion of th bladder, and anastomose with the vesical of the obturator, and th mfeiior vesical of the same side, and with the superior vesical of th opposite side. The superior vesical furnishes the following branches urachal to the medial umbilical ligament; ureteric to the lower end c

THE ABDOMEN

925

L e ureter; and deferential (as a rule) to the vas deferens, though this •anch may arise from the inferior vesical. The artery to the vas deferens, tiich is usually of small size, divides into a descending and an ascendg branch. The descending branch passes downwards to supply the npulla of the vas deferens and the seminal vesicle. The ascending ■anch accompanies the vas deferens through the deep inguinal ring id inguinal canal into the scrotum, supplying the vas deferens, and ving a few twigs to the tail of the epididymis, in which latter situation anastomoses with the epididymal branch of the testicular artery, i the spermatic cord it also anastomoses with the cremasteric branch the inferior epigastric. The artery to the vas is sometimes of large ze, and then takes the place of the testicular artery if that vessel Lould be absent. One of the branches of the superior vesical artery is unetimes spoken of as the middle vesical.

The inferior vesical artery (V) takes an inward course to the lower )rtion of the bladder, which it supplies, giving branches to the seminal isicle, ampulla of the vas deferens, and prostate gland, and in the male to the vagina. It sometimes gives off the artery to the vas derens, and it may give origin to an accessory pudendal. It anastooses with the superior vesical and middle rectal of its own side, and ith its fellow of the opposite side.

The middle rectal artery (middle hsemorrhoidal artery) (V) often 'ises in common with the inferior vesical. It is distributed to the ctum, and gives branches to the seminal vesicle, ampulla of the vas derens, and prostate gland. The anastomoses which it establishes 'e with the superior rectal of the inferior mesenteric, the inferior

ctal of the internal pudendal, the inferior vesical of its own side, and

s fellow of the opposite side.

The obturator artery (P) passes along the outer wall of the pelvic ivity on its way to the obturator canal, lying between the parietal dvic fascia and the peritoneum. It has the obturator nerve above , and its own vein below it. In entering the obturator canal, by which emerges from the pelvis, the artery does not pierce the parietal pelvic

scia, but passes over its upper border, where that joins the upper part

• the obturator membrane. As the artery passes along the pelvic wall furnishes the following branches: muscular to the obturator internus ; iac to the iliac fossa, which supplies the bone, psoas major, and iliacus, id anastomoses with the iliac branch of the ilio-lumbar; vesical, which caches the side of the bladder within the lateral false ligament; and ubic to the back of the body of the os pubis, where it anastomoses with ie pubic branch of the inferior epigastric from the external iliac, and s fellow of the opposite side.

For the distribution of the obturator artery outside the pelvis, P- 589 The obturator artery sometimes arises from the inferior epigastric iee P. 566).

The internal pudendal artery (internal pudic artery) (P) is one of

ie terminal branches of the anterior division. It descends with the

926

A MANUAL OF ANATOMY

inferior gluteal artery upon the pyriforrnis and sacral nerves, a emerges from the pelvis through the lower compartment of the grea sciatic foramen, having previously pierced the parietal pelvic fas( The intrapelvic branches of the vessel are unimportant, and are c tributed to the pyriforrnis, coccygeus, obturator internus, and pel fascia. For the further course and distribution of the artery, see 1 gluteal region and the perineum, pp. 539 and 686.

The inferior gluteal artery (sciatic artery) (P) is the other and lap terminal branch of the anterior division. It descends, usually behi the internal pudendal, upon the pyriforrnis and sacral nerves, a emerges from the pelvis through the lower compartment of the grea sciatic foramen, having previously pierced the parietal pelvic fasc Within the pelvis the artery gives off branches to the pyriforrnis, levai ani, coccygeus, rectum, bladder, seminal vesicle, and prostate glar Although very variable in their origin and course, the inferior gluti artery as it runs backwards frequently passes between the anter: primary divisions of the first and second sacral nerves and the interi pudendal between those of the second and third sacral nerves.

For the extrapelvic course and distribution of the vessel, see p. 5'

Posterior Division. —The ilio-lumbar artery (P) passes upwards a: outwards in front of the sacro-iliac articulation, between the lurnt sacral trunk and obturator nerve. In its course it passes behind t external iliac, or, it may be, the common iliac, vessels, and also behi] the psoas major and iliacus. On reaching the back part of the ili fossa it divides into two branches, iliac and lumbar. The iliac brant passing transversely, ramifies in the iliacus and ilium, and anastomos with the iliac branch of the obturator and branches of the deep circui flex iliac from the external iliac. The lumbar branch ascends benea the psoas major on to the quadratus lumborum, where it anastomos with the terminal part of the deep circumflex iliac, and the last lumb of the abdominal aorta. In its course it furnishes a spinal branch, whi< enters the vertebral canal through the intervertebral foramen betwe^ the fifth lumbar and first sacral vertebrae, to be distributed in a mann similar to the other spinal arteries.

The lateral sacral arteries (P) are usually two in number, superi and inferior. They course downwards and inwards to the front the lateral mass of the sacrum, passing in front of the pyriforrnis ar sacral nerves. Upon the sacrum both arteries lie lateral to the anterf sacral foramina, the superior being confined to the region of the fir two foramina, whilst the inferior descends as low as the coccyx, whe: it anastomoses with the median sacral artery. They are distributf to the pyriforrnis and sacral nerves, and furnish spinal branches, whic enter the anterior sacral foramina, and so reach the sacral canal, whe] they supply its contents. Each spinal branch, before entering tl sacral canal, gives off a posterior branch, which emerges through tl posterior sacral foramen, and anastomoses with branches of the superk and inferior gluteal and internal pudendal. The lateral sacral arterk anastomose with each other and with the median sacral.

THE ABDOMEN

927

The superior gluteal artery (P) is a large vessel, which is the connation of the posterior division. It is destined for the supply of the iteal region, and lies within the pelvis for a very short distance. Its ■ection is backwards through the parietal pelvic fascia, and between 3 lumbo-sacral trunk and the anterior primary division of the first

ral nerve, its escape from the pelvis being through the upper comrtment of the greater sciatic fordfaten. The branches of the artery

thin the pelvis are unimportant.

For the extrapelvic course and distribution of the vessel, see p. 536. The branches of the internal iliac, with one exception, have to irce the pelvic fascia. The exception is the obturator artery, which, stated, passes over the upper border of the parietal pelvic fascia at e obturator canal.

Internal Iliac Vein. —This vessel results from the union of tributaries lich correspond, for the most part, with branches of the internal ic artery. The ilio-lumbar vein, however, is an exception, inasmuch it is a tributary of the common iliac vein. Moreover, during foetal 3 the umbilical vein, which corresponds to the umbilical artery, passes the liver after entering the abdomen of the foetus. The internal iliac in extends from the upper part of the greater sciatic notch to the

ro-iliac articulation on a level with the pelvic brim, where it joins

e external iliac, and so the common iliac vein is formed. In its course lies behind the corresponding artery. There are no valves in the vein elf, but its branches are freely provided with them.

The internal iliac vein is developed from the lower part of the cardinal in.

Internal Iliac Lymphatic Glands. —These glands are about ten in mber, and are associated with the origins of the branches of the ternal iliac artery. They are arranged in a curve, which usually gins in front in a gland situated between the obliterated umbilical d obturator arteries, and then is formed in succession by uterine prostatic, inferior gluteal and internal pudendal, middle rectal, perior gluteal and sacral glands. They are situated immediately ider the peritoneum, between it and the parietal layer of pelvic fascia, though occasionally some of them may be formed lateral to this scia.

The afferent vessels of the internal iliac glands return lymph from e parts supplied by the branches of the internal iliac artery. Thus, ey receive afferent vessels from the following parts:

1. The anal canal, but not the anal margin.

2. Lower part of the rectum.

3- Bladder.

4- Seminal vesicle and vas deferens.

5 - Prostate gland.

6. Prostatic, membranous, and bulbar portions of the urethra, part.

7 - Uterus (cervix).

8. Vagina.

928

A MANUAL OF ANATOMY

9. Deep structures of gluteal region, supplied by superior glu artery.

10. Deep structures of upper part of back of thigh, supplied inferior gluteal artery.

11. Obturator region.

12. Deep structures of perineum.

The efferent vessels of the internal iliac glands pass to the mic group of common iliac glands.

Anterior Primary Divisions of the Sacral and Coccygeal Ner

—There are five sacral nerves and one coccygeal nerve on either s The anterior primary divisions of the first four sacral nerves enter

pelvis through the anterior sa< foramina, and that of the fifth sa< passes between the inferior lab angle of the sacrum and the trt verse process of the first coc geal vertebra, through the coccyg muscle. The anterior primary d sion of the coccygeal nerve enl the pelvis below the transverse j: cess of the first coccygeal verte through the coccygeus muscle. ' first and second sacral nerves of large size, and their course obliquely downwards and outwai Beyond the second they dimin rapidly in size, and pass more h< zontally. They receive grey rz communicantes from the adjao ganglia of the pelvic sympathy trunk, and the third and fou] nerves (sometimes also the secoi furnish white rami communican to the corresponding pelvic plex The anterior primary divisions of 1 first and second sacral nerves divi each into an anterior or ventral and a posterior or dorsal bran< dhe anterior primary division of the third sacral nerve divides ir an upper and a lower branch and is known as the nervus bigemin\ The anterior primary division of the fourth sacral nerve also divic into an upper and a lower branch, and it is known as a nervus furcal The lumbo-sacral trunk in two divisions, ventral and dorsal, the anted primary divisions c>f the first two sacral nerves, the upper and low branches of the third sacral, and the small upper branch of the four sacral form the sacral plexus, whilst the large lower branch of the four sacral, the fifth sacral, and the coccygeal form the coccygeal plexus.

Sacral Plexus. —This plexus, formed as stated, is a large flatten mass, lying upon the pyriformis muscle, and behind the parietal pel\

Fig. 544.— Plan of Position of Structures lying on the Front of the Sacrum.

LSA, lateral sacral arteries; MSA, middle sacral arteries; C, coccygeal ganglion ; SS lig., sacrospinous ligament.

THE ABDOMEN

929

cia, which separates it from the inferior gluteal and pudendal vessels. 3 mass ultimately forms two bands, upper and lower. The upper sciatic band, which is the larger of the two, receives the lumbo-sacral nk, first sacral, larger portion of the second sacral, and upper branch the third sacral nerves. It is flat and somewhat triangular, and is itinued into the sciatic nerve, whjch leaves the pelvis through the r er part of the greater sciatic foramen below the pyriformis without rcing the parietal pelvic fascia. The upper band and its contributory ves are sometimes spoken of as the sciatic plexus . The lower or

A

^ IG - 545-— A, The Sacral Plexus; B, The Sacro-Coccygeal Plexus.

A B

c > 1 , 1 . Nerve to Quadratus Femoris 4 .S. Fourth Sacral, giving a Branch to Sacral Plexus

l > 2 > 2 - Nerve to Obturator Internus V. Visceral Branches

b 3> 3- Posterior Cutaneous Nerve of Thigh M. Muscular Branches

T.C. Terminal Cutaneous Branches

endal band, the smaller of the two, receives fibres from the second er branch of the third, and upper branch of the fourth sacral nerves, ^ is continued into the pudendal nerve, which leaves the pelvis, like the tic, through the lower compartment of the greater sciatic foramen hout piercing the parietal pelvic fascia. The lower band and its tributory nerves are sometimes spoken of as the pudendal plexus. ' sciatic and pudendal nerves are thus the terminal branches of the r al plexus. The reason of the name nervus bigeminus, as applied to third sacral nerve, is because it enters into the sciatic band by its )er branch, and into the pudendal band by its lower branch.

59

930

A MANUAL OF ANATOMY

Branches. —The branches of the sacral plexus are arranged in groups—collateral and terminal.

Collateral Group. —The branches of this group form three sel visceral, muscular, and cutaneous.

Visceral Branches. —These are derived from the third sacral that part of the fourth which enters into the sacral plexus (someti: also from the second). They are white rami communicantes, wl reinforce the pelvic plexus of the sympathetic, a few of them b( traceable independently to the pelvic viscera. They are known as pelvic splanchnics.

Muscular Branches .—The superior gluteal nerve arises by< tl roots from the dorsal divisions of the descending branch of the for lumbar, fifth lumbar, and first sacral nerves. It passes outwards backwards, and leaves the pelvis with the superior gluteal artery thro the upper compartment of the greater sciatic foramen, to be distribr to the gluteus medius, gluteus minimus, and tensor fasciae latae muse The inferior gluteal nerve arises by three roots from the do divisions of the fifth lumbar and first and second sacral nerves, leaves the pelvis through the lower compartment of the greater sci foramen, below the pyriformis and dorsal to the sciatic nerve, to distributed to the gluteus maximus. It is usually intimately associa with the posterior cutaneous nerve of thigh.

The nerves to the pyriformis, which are usually two in numl spring from the dorsal divisions of the first and second sacral nerve The nerve to the obturator internus and gemellus superior ar by three roots from the ventral divisions of the fifth lumbar and t and second sacral nerves. It leaves the pelvis through the lo compartment of the greater sciatic foramen, crosses the back of ischial spine, where it lies lateral to the internal pudendal vessels, ; then passes through the lesser sciatic foramen to the outer wall of ischio-rectal fossa, where it enters the inner or pelvic surface of obturator internus. In the gluteal region it gives a branch to gemellus superior when that muscle is present.

The nerve to the quadratus femoris and gemellus inferior arises three roots from the ventral divisions of the descending brand] the fourth lumbar, fifth lumbar, and first sacral nerves. It leaves pelvis through the lower compartment of the greater sciatic foran and then lies between the ischium and the sciatic nerve. It s sequently descends over the back of the capsular ligament of the 1 joint, to which it usually gives a branch, and beneath the gemelli; obturator internus to the deep surface of the quadratus femoriSj which it ends, having previously given a branch of the gemellus infer Cutaneous Branches .—The posterior cutaneous nerve of thigh (sr sciatic nerve) arises by three roots from the posterior aspects of first, second, and third sacral nerves. It leaves the pelvis through lower compartment of the greater sciatic foramen, and is distribu to (i) the lower and outer part of the gluteal region by its glui cutaneous branches, (2) the skin of the scrotum by the long perir

THE ABDOMEN

93 i

rve, (3) the skin of the back of the thigh, and (4) the skin of the back the leg as low as about the centre of the calf.

The perforating cutaneous nerve arises by two roots from the sterior aspects of the second and third sacral nerves. It passes ckwards through the sacro-tuberous ligament, after which it turns and the lower border of the glutefis maximus near the coccyx to be stributed to the skin over the lower and inner part of that muscle. Terminal Group. —This group is comprised of two nerves—namely, e sciatic and the pudendal.

The sciatic nerve is the continuation of the upper or sciatic band of e sacral plexus. In reality it is made up of the two divisions in which ultimately ends—namely, the lateral and medial popliteal—which lie >se together within the same sheath. Sometimes, however, these two visions arise separately from the sacral plexus, in which cases the

eral popliteal nerve may pass through the pyriformis. Again,

ough the sciatic nerve may be apparently single, a careful dissection it, after the removal of its sheath, will reveal the lateral and medial pliteal nerves, which can be shown to have independent origins. The

eral popliteal nerve derives its fibres from the dorsal divisions of the

scending branch of the fourth lumbar, fifth lumbar, and first and

ond sacral nerves; and the medial popliteal nerve derives its fibres

>m the ventral divisions of the foregoing nerves, and in addition from e upper branch of the third sacral.

The sciatic nerve leaves the pelvis through the lower compartment the greater sciatic foramen below the pyriformis.

The pudendal nerve (pudic nerve) is the continuation of the lower pudendal band of the sacral plexus. It arises by three roots from e ventral division of the second, the lower branch of the third, and e upper branch of the fourth sacral, the root from the third being e largest. The nerve leaves the pelvis through the lower compartsnt of the greater sciatic foramen, crosses the back of the ischial ine, where it lies medial to the internal pudendal vessels, passes rough the lesser sciatic foramen, and then traverses the outer wall of e ischio-rectal fossa. Having given off the inferior haemorrhoidal rve, it divides into the perineal and dorsal nerve of penis, which th the internal pudic vessels are contained in the pudendal canal.

The sacral plexus and its branches being situated behind the parietal fvic fascia, the branches do not pierce the fascia as they leave the Ivis. The branches of the internal iliac artery, on the other hand, ing placed in front of the parietal pelvic fascia, have to pierce it, th the single exception of the obturator artery.

Coccygeal Plexus. —The nerves which form the plexus are the wer branch of the anterior primary division of the fourth sacral, the terior primary division of the fifth sacral, and the anterior primary vision of the coccygeal nerve. The upper branch of the fourth sacral ters the pudendal band of the sacral plexus, and the fourth sacral therefore a nervus fur calls, inasmuch as it gives a branch to the sacral exus and one to the coccygeal plexus. Before entering the coccygeal

932

A MANUAL OF ANATOMY

plexus the lower branch of the fourth sacral nerves gives off visce: and muscular branches. The visceral branches for the most part re: force the pelvic plexus of the sympathetic as white rami commu: cantes, but a few of them pass independently to the pelvic visce: The muscular branches supply the levator ani, coccygeus, and sphincl ani externus. The branch to the latter muscle reaches the perinei either by piercing the coccygeus, or by passing between it and t levator ani, and besides supplying the external sphincter, it gi\ branches to the skin between the coccyx and the anus. The nerve known as the perineal branch of the fourth sacral. The lower bran of the fourth sacral nerve, having parted with the foregoing offse descends upon the coccygeus, where it joins the fifth sacral, which h just entered the pelvis through that muscle. The conjoined nerve n< descends, and is soon reinforced by the coccygeal nerve, which a] enters the pelvis by piercing the coccygeus. In this manner t coccygeal plexus is formed. It lies at the lower part of the posted wall of the pelvis upon the coccygeus, and the nervous loop takes downward course. Subsequently it divides into several twigs, whi leave the pelvis by piercing the coccygeus, the sacro-spinous ligamei and the adjacent portion of the gluteus maximus to be distributed the skin over the coccyx.

Ureters. —The ureter of each side, having crossed the terminati of the common iliac, or the commencement of the external iliac artei enters the pelvis. It then passes downwards, describing a curve wi its convexity backwards and outwards, lying in front of the interr iliac artery. It next runs along the outer wall of the pelvis, lyi: beneath the peritoneum, and crossing medially the obturator vess< and nerve, and the obliterated umbilical artery. It subsequent passes inwards to the bladder, being crossed medially by the vas deferer Haying arrived at the lateral or ureteric angle of the bladder, it pass obliquely through the vesical wall anterior to the upper free end of t seminal vesicle, being here about 2 inches distant from its fellow, ai about 1 \ inches from the base of the prostate gland.

Bladder. —The bladder, when empty, or only moderately d: tended, lies entirely within the cavity of the pelvis. When, howeve it is fully distended, the apical part of the viscus rises above the le\ of the symphysis pubis into the hypogastric region of the abdonn for at least 2 inches, and in cases of marked over-distension it may rea< to the umbilicus, or even higher. The bladder, therefore, has to 1 considered under two aspects—namely, when empty or only moderate distended, and when fully distended.

The bladder, when empty or moderately distended , is triangular, ai presents the following component parts: an apex, a base, and a bod the latter presenting a superior surface, two inferior lateral surface two lateral borders, a posterior border, an antero-median border, ai two lateral angles.

The apex is directed forwards, and lies behind the upper part of t] symphysis pubis. It has connected with it the median umbilic

THE ABDOMEN

933

lament representing the urachus , which ascends on the posterior rface of the anterior abdominal wall to the lower part of the umlicus. The base or fundus is directed backwards and downwards wards the rectum, from which it is separated by the seminal vesicles id terminal portions of the vasa deferentia, and the recto-vesical mina of the visceral portion of the pelvic fascia. The base is separated Dm the superior surface by the posterior border, and from each unded inferior lateral surface by a slight elevation, which extends Dm the lateral or ureteric angle of either side to the urethral opening, le superior surface is three-sided and slightly convex. It is usually lated to a few coils of the small intestine, and a loop or two of the lvic colon. The inferior lateral surfaces , which are convex, rest

d. 546.—Showing the Internal Trigone of the Bladder and the Relations of the Vas Deferens (DD), Ureter, etc., in its Neighbourhood.

'On (1) the symphysis pubis and the adjacent portions of the posterior rfaces of the bodies of the pubic bones, (2) the retro-pubic pad of “» ( 3 ) the medial pubo-prostatic ligaments, (4) the fasciae covering e u pper part of the obturator internus muscle and the upper surface the levator ani, and (5) the prostate gland. The lateral borders start )m the apex, whence they pass backwards in a diverging manner, and ch marks the separation between the superior surface and the correonding inferior lateral surface. Posteriorly each lateral border meets e posterior border. The posterior border extends transversely beeen the superior surface and the base. At either end it is joined by s lateral border. The lateral or ureteric angles are situated on either e at the junction of the lateral with the posterior border. At these gles the ureters pass through the vesical wall (Fig. 546). At its

934

A MANUAL OF ANATOMY

most dependent point the bladder is continuous with the uretl There is, however, no contraction of the bladder at or near this poi in other words, no neck.

The external trigone is the name given to a limited triangular sp upon the exterior of the base, which is bounded as follows: above, the bottom of the recto-vesical pouch of peritoneum; laterally, by ampulla of the vas deferens, lateral to which is the seminal vesic and below, by the approximation of the ejaculatory ducts at the b of the prostate gland. The length of the space from the apex be] to the base above is, as a rule, fully i inch, but its breadth is limi by the encroachment upon it of the ampullae of the vasa deferen There is no peritoneum over this region.

The Bladder during Distension and when fully distended. —As bladder becomes distended very little alteration takes place in a doi,

ward direction. The

Left Ureter

Line of

Reflection of-' Peritoneum

External Trigone

Ejaculatory Duct of Right Side

THE

marcations between i component parts of i viscus gradually disappe and it becomes ovoid. 1 apex appears above 1 symphysis pubis, and the organ increases in s the apex and the super portion of the body asce into the hypogastrium such a manner as to st: off the parietal peritonei from the back of the lin alba. In this way a p< tion of the original inferi lateral surface, devoid

Fig. 547. —Dissection of the Base of . . , , .

Bladder, showing the Seminal Vesicles, peritoneum, is brought in Vasa Deferentia, and External Trigone, direct contact with t

back of the linea all which is now also free from peritoneal covering. A distended bladd may therefore be punctured or opened through the linea alba abo the symphysis pubis without doing any injury to the peritoneui The bladder is now becoming spheroidal, and its long axis is direct downwards and backwards. The part which rises highest is not t original urachal apex, but that part of the superior surface which immediately adjacent to, and behind, the apex.

Peritoneal Relations. —The only part of the bladder which is coven by peritoneum is the superior surface. The peritoneum is reflect! from the apex along the urachus, and at either side it leaves the org; along the lateral border. When the bladder is distended the latei reflection of peritoneum appears to take place along the course of t; obliterated umbilical artery, but this is due to the lateral distensh and elevation of the viscus, the obliterated umbilical itself lying aloi

THE ABDOMEN

935

outer wall of the pelvis. For the structure and development of bladder, see pp. 949 and 955.

Vas Deferens in the Pelvis. —The vas deferens enters the abdomen )ugh the deep inguinal ring, where it lies on the inner side of the er constituents of the spermatic cord.- It then hooks round the er side of the inferior epigastric artery, and having crossed the ernal iliac vessels from without inwards, it dips down on the inner

of the external iliac vein. In this way it enters the pelvis under

er of the peritoneum. It now passes backwards and downwards >n the lateral wall, crossing median to the obliterated umbilical ery, the ureter, and the obturator vessels and nerve. It is then

Symph. Pub.

Fig. 548. —Transverse Section through Last Piece of Sacrum

(after Symington).

ected inwards to the inner aspect of the upper end of the seminal side, whence it passes downwards, inwards, and forwards along the se of the bladder, where it lies close to the inner side of the seminal side. This part of the vas deferens, which comes very near its fellow, lilated and sacculated, like the adjacent seminal vesicle, and is known the ampulla. Close to the base of the prostate gland the sacculans disappear, and the duct, having become very narrow, is joined the outer side at an acute angle by the duct of the seminal vesicle, and the ejaculatory duct is formed, which will be presently described. t the structure and development of the vas deferens, see pp. 737 d 753

936

A MANUAL OF ANATOMY

Seminal Vesicles. —These are two in number, right and left, and between the base of the bladder and the rectum. They are sacculat reservoirs for the seminal fluid, and each is conical, being about 2 incl long, and about J inch broad at the widest part. The broad end free, and looks upwards, outwards, and backwards. It is covei posteriorly in its upper part by the peritoneum, which forms the rec vesical pouch, while anterior to it is the ureter as that is about to p; through the bladder. The upper ends of the two seminal vesicles ; wide apart, and the bottom of the recto-vesical pouch descends betwf

AnalCanal

Bulb of Corp.

Spong.

Ureter

V. Def. Bladder

Prostate

Fig. 549.—Median Sagittal Section through Male Pelvis.

them for a short distance. The lower end of each, which is nari and free from sacculations, approaches its fellow, the vasa deferer intervening. This lower end represents the duct, which, as stat joins the vas deferens at an acute angle close to the base of the prost gland, and so gives rise to the ejaculatory duct. For the struct and development of the seminal vesicles, see p. 958.

Ejaculatory Ducts. —These are two in number, right and left. E«  is formed by the union of the duct of the seminal vesicle with the deferens close to the base of the prostate gland; it is about 1 inch

THE ABDOMEN

937

ngth. The two ducts pass downwards, forwards, and inwards through e prostate gland between the middle and lateral lobes, and each enters e lateral wall of the prostatic utricle to terminate in a minute aperture i the lateral margin of the opening of the prostatic utricle. For the ructure and development of the ejaculatory ducts, see p. 955. Prostate Gland. —This gland surrounds the first ij inches of the ethra. It is firm in consistence, and in shape and colour resembles chestnut—that is to say, it is conical and of a reddish-brown colour, is subject to much variety in size, but its average measurements ay be stated as follows: the transverse diameter at the base is about inches; the vertical diameter from base to apex is about ij inches;

Sperm. Cord Corp. Cavern.

t \

/ \ >

Coccyx Rectum

Fig. 550 -—Transverse Section at Level of Coccyx (after Symington).

id the antero-posterior diameter is about f inch. The average weight

the organ is about \\ drachms.

The gland is situated fully ij inches from the anus, and its anterior irface is about f inch below and behind the lower part of the symphysis ubis. It presents a base, an apex, a posterior or rectal surface, an iterior or pubic surface, and two lateral surfaces. The base, which directed upwards, surrounds the urethra, and is intimately connected ith the vesical wall. Notwithstanding this, however, there is a supernal line of demarcation between the two, which takes the form of an mular groove, occupied by a portion of the prostatic venous plexus, be ejaculatory ducts enter the base close to the upper part of the asterior or rectal surface, where there is a small transverse cleft died the prostatic fissure. The apex is directed downwards, and is

938

A MANUAL OF ANATOMY

the most dependent part of the organ. It is in contact with the super layer of the perineal membrane. The posterior or rectal surface is f and triangular. It is directed backwards and slightly downwar and is set upon the anterior wall of the rectum, from which it is separal by the recto-prostatic lamina of the visceral portion of the pelvic fast This surface is accessible to manipulation on introducing the finger ir the anal canal, and carrying it up for fully ij inches. The anterior pubic surface, which is convex, is so much projected as to be really anterior round border which separates the two lateral surfaces. Itl about § inch behind the lower part of the symphysis pubis, from wh: it is separated by a portion of the prostatic venous plexus, the ret pubic pad of fat, and the medial pubo-prostatic ligaments. 1 anterior surface projects between the anterior borders of the levato ani muscles. The lateral surfaces are convex, and stand out in 1 relief. Each is embraced by the anterior fibres of the correspond] levator ani, which constitute the so-called levator prostatae muse When an accessory pudendal artery is present it passes over the late surface, and might be endangered in lateral lithotomy.

The gland is usually regarded as composed of three lobes, t 1 lateral and a middle, but, though the middle lobe can usually demarcated without much difficulty, there is no external indicati of any separation between the lateral lobes. The lateral lobes foi the chief bulk of the gland, and they meet and become continuous front of and behind the prostatic portion of the urethra, forming t anterior and posterior commissures. The middle lobe represents tl part of the basal portion of the gland which is wedged in between t ejaculatory ducts and prostatic utricle behind and the urethra in fra and which lies just below the apex of the trigonum vesicse. It is i: portant to note that the middle lobe lies behind the commencement the urethra. It is liable to become hypertrophied in old age, and m then produce undue elevation of the uvula vesicae in the interior of t bladder, which is a natural product of it. In this manner, by blocki the internal orifice of urethra, it may not only give rise to difficulty micturition, but may also obstruct catheterization.

The prostate gland is traversed by the first i J inches of the ureth: The ejaculatory ducts are also contained within the gland, in which th pass downwards and inwards between the middle and lateral lob' For the structure and development of the prostate gland, see pp. 9 and 960.

Urethra. —The male urethra commences at the internal orifice urethra of the bladder, and terminates at the extremity of the gla penis in a vertical fissure, called the external orifice of urethra. It about 8 inches in length, and is divided into three portions, whit from the bladder outwards, are called prostatic, membranous, a spongy. The prostatic and membranous portions constitute t non-penile part of the canal, and the spongy portion, being contain within the corpus spongiosum of the penis, represents the per part.

THE ABDOMEN

939

rhe prostatic portion of the urethra is the part of the canal which ontained within the prostate gland. It is inches in length, its course is almost vertical, there being a slight curve with the

avity directed forwards. It is spindle-shaped, being wider at the

re than at either end, and at its upper or vesical end it is rather

sr than at the lower end. Its diameter at the centre, which is the est part of the entire canal, is rather more than ^ inch; at the upper r esical end it is rather less than this, and at the lower end it is still . This portion of the urethra, though surrounded by the -prostate id, is the most dilatable part of the whole canal. Close to the Ider, however, it usually offers some resistance to the passage of an rument. Its walls are anterior and posterior, the latter being often ken of as the floor. These walls are in contact with each other, spt during the passage of fluid, and the mucous membrane is thrown ) longitudinal folds. The posterior wall presents along the middle

Median Umbilical Ligament

ig. 551.—Section of the Bladder and Penis to show the Urethra.

i a prominent narrow elevation of the mucous membrane, called the thral crest (verumontanum). It is about f inch long, and comnces either a little below the urethral orifice of the bladder or at the r er end of the uvula vesicas. As it descends it gradually becomes re prominent, assuming a height of about J inch, and then rapidly >sides. It is due to a thickening of the submucous tissue, which lses an elevation of the mucous membrane. On account of this protion a transverse section of this portion of the urethra is curved or scentic, with the convexity directed forwards. On either side of the st there is a longitudinal groove, called the prostatic sinus, into which ^ majority of the prostatic ducts open. A few of these ducts, howT from the middle lobe open in the median line above the crest, or, he crest commences at the lower end of the uvula vesicae, upon its per part. Immediately below the most prominent part of the crest

• e is the opening of a small blind recess, called the prostatic utricle

94°

A MANUAL OF ANATOMY

(sinus pocularis). Its direction is upwards and backwards behind t' middle lobe of the prostate, and it is from £ to J inch in length. It somewhat flask-shaped, being narrow at its urethral orifice, but e panded at its deep csecal end. It may extend beyond the prostate ai is sometimes bifid. Upon the lateral margins of its orifice are the minu openings of the ejaculatory ducts. The utricle represents the uter and vagina in the female, being developed from the fusion of the posted or caudal ends of the para-mesonephric ducts.

When the middle lobe of the prostate becomes hypertrophied blocks the urethral orifice of the bladder, as has been stated, by press! the uvula vesicae over it from behind, and so gives rise to difficulty micturition, and obstructs catheterization. When both lateral lob become uniformly hypertrophied, the prostatic portion of the ureth undergoes increase in length. When only one lateral lobe is involv in the hypertrophy it presses against the urethra, and, producing d tortion of the canal, gives rise to difficulty in micturition, and oft considerable obstruction in catheterization.

Structure. —The mucous membrane of the prostatic urethra surrounded externally by the inner circular muscular fibres of t prostate, and is covered internally by transitional epithelium.

The membranous portion of the urethra si;cceeds to the prostai portion, and extends from the apex of the prostate gland to the coi mencement of the spongy portion. It is contained, for the most pa: between the two layers of the perineal membrane, but it also exten for a short distance (J inch) beyond the inferior layer of that structm It is the shortest and narrowest part of the canal, with the except! of the external orifice of urethra. Its length is £ inch along the anteri wall, and J inch along the posterior, the difference being due to t fact that the membranous urethra passes into the spongy part in slanting manner at a point £ inch in front of the posterior extremi of the bulb. The back part of the bulb projects backwards for £ in over the posterior wall of the membranous urethra, and is here lyi in front of the inferior layer of the perineal membrane. It is in tl situation where a false passage is liable to be made in catheterizatic partly because the walls are here very thin, and partly by reason the backward extension of the posterior extremity of the bulb. T. diameter of the membranous urethra is £ inch. It lies about i m behind and below the inferior ligament of symphysis pubis, and ] direction is downwards and slightly forwards. It describes a geni curve, the concavity of which looks forwards and upwards towards t lower part of the symphysis pubis. As the membranous urethra pass through the superior layer of the perineal membrane, which is form by the parietal pelvic fascia, the fascia is prolonged upwards to foi part of the capsule of the prostate gland. Moreover, as it pierces t inferior layer of the perineal membrane about i inch below the syi physis pubis, it carries with it a prolongation from the margins of t urethral opening, which forms a fascial investment for the bulb, h tween the two layers of the perineal membrane the membranous ureth

THE ABDOMEN

94 1

irrounded by the fibres of the sphincter urethrae muscle, and the o-urethral glands lie behind it, one on either side of the middle

Structure. —External to the mucous membrane there is a layer of tile tissue, and outside this there is a layer of circularly-disposed 1 muscular fibres,

h are continuous I "* e ™ laic: vesic*

/e with the circular Bell’s Muscle I ; Left Ureteric Opening

cular fibres of the itate around the proic urethra. External his, again, there are sphincter fibres of sphincter urethrae, mucous membrane is ned by columnar epium. The membranportion of the urethra ransverse section pre:s the appearance of ircular opening, the len of which is iched, this being due the longitudinal folds • which the mucous nbrane is thrown.

The spongy portion of urethra succeeds to membranous portion, is contained within corpus spongiosum of penis, and extends n a point \ inch in it of the posterior exility of the bulb and the inferior layer of perineal membrane the external orifice of thra on the extremity the glans penis. It is

nit 6 inches in length, External Orifice of Urethra

1 its calibre is unequal Fig oughout. It presents i dilatations, one situated in the bulb, the intrabulbar fossa (which •resents about the first ij inches of the corpus spongiosum), and

other in the glans penis, the latter being called the terminal

sa (fossa navicularis). The intrabulbar fossa is about ij inches in gth, whilst the terminal fossa is about J inch long. The diameter

-Crest

-Opening of Utricle

Prostate Gland in Section (showing Prostatic Portion of Urethra)

-Membranous Portion of Urethra

Bulbo-urethral Gland of Left Side

Left Half of Bulb of Urethra

Left Crus Penis

Openings of Ducts of Bulbourethral Glands

-Spongy Portion of Urethra

- [-Left Corpus Cavernosum

-Urethral Glands and Lacunas

Urethrales

-Terminal Fossa

-Left Half of Glans Penis

-The Interior of the Male Urethra.

94 2

A MANUAL OF ANATOMY

of that part of the spongy urethra which intervenes between the in bulbar fossa and the terminal fossa is about J inch. At the extei orifice of urethra the calibre of the canal is diminished, this being narrowest part of the entire canal. The spongy portion at its o mencement is directed forwards for a short distance, and then be downwards. It thus describes a curve, which is situated about 2 inc from its commencement, the concavity being directed downwa: This curve is fixed, and corresponds with the angle of the penis, the sit tion of which is immediately in front of the penile attachment of suspensory ligament, where drooping of the organ takes place, walls of the spongy part of the urethra are in contact, except dui the passage of fluid. A transverse section of it, except in the gk presents a transverse slit with anterior and posterior lips. In the gk however, the slit is vertical with its lips laterally disposed. At upper end of the terminal fossa—that is, the end most remote from external orifice of urethra-—the vertical slit is modified by the addil of a short transverse slit, and so presents the shape of an inverted as follows, J_.

Structure. —The mucous membrane of the spongy portion is j vided with elastic tissue, and is very vascular. It is covered columnar epithelium , except in the glans, where it is of the strati squamous variety. Outside the mucous membrane is the subrnuc coat, which contains two layers of plain muscular tissue—inner loi tudinal and outer circular. External to the submucous coat ther a plexus of veins, which forms part of the corpus spongiosum. ' mucous membrane contains both simple and compound mucous glar called the urethral glands (glands of Littre), the openings of the dr of which are studded over the surface. In addition to these there other openings, which lead into small blind recesses, called the lacr urethrales, these openings being directed forwards. One lacuna, large size, called the lacuna magna, is situated on the roof of the fc navicularis about 1 inch from the meatus urinarius. The muc membrane which surrounds this lacuna is known as the valvule Guerin. Besides the foregoing openings, the ducts of the bul urethral glands open upon the floor of the bulbous portion of the uret. about 1 inch in front of the inferior layer of the perineal membrane.

There is sometimes a congenital deficiency in the floor of the spoi urethra, constituting the condition known as hypospadias. In ot cases the deficiency may be on the roof, and it is then known epispadias.

Lymphatics of the Male Urethra—Spongy Portion. —The lymphs vessels of the spongy portion communicate with those of the glans £ with the deep lymphatics of the penis, and in part through this conn tion drain to the deep inguinal and external iliac glands. Much of' lymph, however, from this region drains into vessels which, accc panying first the vessels of the bulb and later the internal pudic vess< finally pass to the gland or glands of the internal iliac chain , which situated near the origin of the internal pudendal artery.

THE ABDOMEN

943

ulbar and Membranous Portions. —The lymphatics of these portions to (i) the internal iliac glands, and (2) the inner chain of the external glands.

rostatic Portion. —The lymphatics of this portion join those of the

ance of the prostate gland, and pass to (1) the middle chain of

xternal iliac glands, (2) the internal iliac glands, (3) the lateral l glands, and (4) the inner group of the common iliac glands. elvic Colon. —The pelvic colon succeeds to the iliac colon. It nences at the inner border of the left psoas major just anterior to jft sacro-iliac articulation, and terminates in front of the third sacral ibra, where it becomes continuous with the rectum. It is very ible in length, but measures on an average about 15 inches, and lly lies in the pelvic cavity, resting upon the bladder and rectum, ascending on either side of these viscera. It is surrounded by peri11m, which forms behind it an expanded wavy mesentery, called the 0 meso-colon, which contains between its two layers the branches ie lower left colic arteries and the superior rectal artery, with the jsponding veins. The root of this mesentery is composed of two 3, which become continuous at an acute angle. One limb takes an ird course along the inner border of the psoas major, and the other ss downwards over the sacral promontory to be attached to the rior surfaces of the first three sacral vertebrae. At its extremities, h are near each other, the mesentery is short, and the extremities of pelvic colon are necessarily fixed. The intervening portion, how, is long, and so allows of considerable mobility on the part of the ter portion of the attached gut. A very common course for the ic colon to take is to pass from the left wall to the right wall of the is, resting upon the bladder or uterus, then to pass backwards wing the posterior wall of the pelvic cavity until it arrives at the lie line, when it turns vertically downwards. A portion of it is itimes met with in the abdominal cavity.

tructure. —The chief difference in the structure of the pelvic colon, impared with the other divisions of the colon, affects the arranget of the longitudinal muscular fibres. Though arranged at first iree taeniae, these gradually become disposed as two broad taeniae, rior and posterior. When this has taken place, the longitudinal s almost surround the gut, except along the sides, in which situa3 the usual sacculations are formed. Appendices epiploicae are met over the pelvic colon.

Wood-supply. —The pelvic colon receives its arteries from the lower colic arteries, which are branches of the inferior mesenteric. The s pass to the inferior mesenteric vein, and ultimately into the al vein.

die lymphatics pass to the left lower pre-aortic glands.

die nerves are derived from the inferior mesenteric sympathetic

us.

tectum. —The rectum succeeds to the pelvic colon, and extends 1 the front of the third sacral vertebra to a point 1J inches in front of

944

A MANUAL OF ANATOMY

and below the tip of the coccyx, where it pierces the pelvic diaphra^ and terminates in the anal canal. Its direction is at first downwa and slightly backwards, then vertically downwards, and finally doi wards and forwards. It is fully 5 inches in length, and its diameter the most part is about ij inches in the empty state, but it becor enlarged above the anal canal, this dilated part being called the ampi recti. When empty, its anterior and posterior walls are in contact, c in transverse section it appears as a transverse slit. The rectun destitute of a mesentery. The peritoneum covers the upper th laterally and anteriorly , but not posteriorly, the middle third be covered by peritoneum only anteriorly , whilst the lower third is f from serous covering. The level at which the peritoneum leaves 1 anterior surface of the rectum is usually about 3 inches above the an opposite the body of the fifth sacral vertebra.

The rectum, so far from being straight in man, presents both ante posterior and lateral curvatures. The antero-posterior flexures ; two in number, upper and lower. The upper curve extends from 1 third sacral vertebra to the posterior or rectal surface of the prost; gland, and its concavity is directed forwards. The lower curve, wh] is abrupt, corresponds with the rectal surface of the prostate, its c( cavity looking backwards, and containing the ano-coccygeal body. T lateral flexures are of importance, because they tend to obstruct t passage of instruments by giving rise to the rectal valves (Housto These flexures are usually three in number—upper, middle, and low The upper and lower flexures have their convexities directed towai the right, whilst the middle flexure has its convexity directed towai the left. In the concavities of these flexures the rectal wall becoir inflected, and so gives rise to more or less prominent shelves of mucc membrane, which are known as the rectal valves. The lateral infk tions and resultant valves are associated with the erect posture of rm which posture throws considerable pressure upon the anal aperture ai its sphincter muscles. They are best marked in the distended recta and the lateral flexures are brought about in the following manner: T longitudinal muscular fibres of the rectum are rather shorter than t gut to which they are applied. Moreover, they are principally dispos' in two stout broad sheets, one on the anterior and the other on t. posterior wall, there being very few longitudinal fibres along the latei walls. The shortness of these longitudinal fibres therefore throws tl rectum into lateral flexures on account of the sparseness of the lon£ tudinal fibres at the sides. These lateral flexures may be taken representing the sacculations of the other parts of the colon.

Relations— Anterior. —The recto-vesical pouch of peritoneum f ( a short distance, usually containing coils of small intestine or of pelv colon; the base of the bladder, seminal vesicles, and vasa deferentia, wf the intervention of the recto-vesical lamina of the visceral pelvic fasci; and the posterior or rectal surface of the prostate gland, with the inte vention of the recto-prostatic lamina of the visceral pelvic fascia. J the female the anterior relations are (1) the recto-uterine pouch

THE ABDOMEN

945

ritoneum (pouch of Douglas), with a few coils of small intestine or dvic colon, in front of which are the posterior surface of the body of e uterus and the upper part of the posterior wall of the vagina; and ) the greater portion of the posterior wall of the vagina. Posterior .— le lower three sacral vertebrae, coccyx, levatores ani, and ano-coccygeal idy; the median and lateral sacral vessels, sacral lymphatic glands, cral nerves, and sacral sympathetic trunk. Behind the rectum there a large amount of areolar tissue. Lateral .—The pelvic sympathetic sxuses, levatores ani, and coccygei muscles, the lateral divisions of e superior rectal artery, and the corresponding veins.

Anal Canal. —This is the terminal portion of the large intestine, extends from the lower end of the rectum, where that has pierced e pelvic diaphragm at a point correonding to the apex of the prostate md, to the anus, and it is the part rich is surrounded by the sphincter uscles. It is about i-| inches in igth, and its lateral walls are in ntact, so that in transverse section appears as an antero-posterior slit, which respect it differs from the ctum proper. Its direction is downirds and backwards, and its antero(sterior diameter is from \ to f inch.

Relations. — Anterior. —The bulb of e penis, the base of the perineal smbrane, and the membranous part the urethra. In the female the rineal body is anterior to it, and parates it from the lower end of e vagina. Posterior .—The ano-coccyal body. Lateral .—The fat of the ririo-rectal fossae. The anal canal is )sely guarded by muscles in the folding manner and to the following tent: most internally is the sphincter

i internus continuous with the circular muscular fibres of the rest the gut; outside this are the longitudinal muscular fibres markedly enforced by the fibres of the levator ani, which here run longidinally; and most externally is the sphincter ani externus. For e structure and development of the rectum and anal canal, see 960.

Fig. 553.—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.

Parts felt per Rectum in Catheterization. —A catheter having been passed k) the bladder, the following parts, in order from before backwards, may be t through the anterior wall of the bowel on the introduction of the index S er: (1) the membranous portion of the urethra; (2) the posterior or rectal rface of the prostate gland; and (3) the apical part of the external trigone of 3 bladder, destitute of peritoneum, with a vas deferens on either side, and very

946

A MANUAL OF ANATOMY

near each other—indeed, almost touching. During this examination the fin may come in contact with the lower left, and perhaps the right horizontal folc rectum.

Median Sacral Artery. —This vessel arises from the posterior asp of the abdominal aorta just above the bifurcation. Its course downwards in the middle line, behind the left common iliac vein a the hypogastric sympathetic plexus, and it rests in succession uj the following parts: the lower half of the body of the fourth luml vertebra and the disc between it and the fifth, the body of the fr lumbar and the disc between it and the first sacral vertebra, and 1 pelvic surfaces of the sacrum and coccyx. In the pelvis it lies wit] the root of the pelvic meso-colon, being covered by a portion of i pelvic colon, as low as the third sacral vertebra, and beyond that il placed behind the rectum. On reaching the tip of the coccyx terminates in the coccygeal body. The branches of the artery are follows: anterior or rectal to the posterior wall of the rectum, where tl anastomose with the superior and middle rectal arteries; lateral to i front of the sacrum and coccyx, which anastomose with the late sacral arteries; and terminal to the coccygeal gland. The vessel usua furnishes a fifth pair of lumbar arteries, which wind round the sides the body of the fifth lumbar vertebra.

The median sacral artery represents the caudal aorta of anima and its lateral branches are serially homologous with the lumt branches of the abdominal aorta.

The median sacral vein is at first arranged as two venae comiti but these subsequently unite to form a single vessel, which usuaj terminates in the left common iliac vein.

Glomus Coccygeum. —This so-called gland is situated in front of t tip of the coccyx. It is about the size of a small pea, and is compos of a few nodules which are held together and invested by connecti tissue. It receives the terminal twigs of the median sacral artery, structure it consists of groups of polyhedral cells united by connecti tissue, and permeated by blood-capillaries and sympathetic ner\ filaments. It is in some respects similar to the carotid body , whi is situated behind the common carotid artery of each side close

its bifurcation, but differs from it in not containing chromap] cells.

Sacral Glands. —This group comprises a few lymphatic glands whi< he in front of the sacrum to the inner side of the second and third saci foramina. They receive their afferent vessels from the various peh viscera, as well as from the posterior wall of the pelvis; their effere vessels pass to the middle chain of common iliac glands.

Sacral Sympathetic Trunk. —This is situated close to the inner si( of the anterior sacral foramina. The two trunks, right and left, co verge as they descend, and in front of the coccyx they are connect* by a loop which sometimes presents a single ihedian ganglion, called tl ganglion impar or coccygeal ganglion. The number of ganglia on ea( trunk is usually four.

THE ABDOMEN

947

b

Branches.— (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,

94 8

A MANUAL OF ANATOMY

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

THE ABDOMEN

949

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.

95°

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

THE ABDOMEN

95i

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

952

A MANUAL OF ANATOMY

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.

THE ABDOMEN

953

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

954

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.

956

A MANUAL OF ANATOMY

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

95§

A MANUAL OF ANATOMY

(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

61

A manual of anatomy

962

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.

968

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

THE ABDOMEN

969

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

THE ABDOMEN

971

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)

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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

t

THE ABDOMEN

989 *

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.

63