The iliac region of the right side is occupied by the ccecum or caput coli, and in the lumbar region of the same side the ascending colon is visible, sometimes when distended projecting considerably, at other times so contracted as to appear sunk towards the posterior wall of this region, and to allow of being overlapped and concealed froin view by some of the convo lutions of the small intestine. In the corres ponding regions of the left side the remaining portions of the colon are seen, and they too are very frequently, if not generally, closely applied to the posterior wall : in the lumbar region the descending colon is much more frequently in a contracted than in a distended state, and in the iliac region, not occupying it to the same extent as its fellow is occupied by the ccecum, we find the sigmoid flexure of the colon winding its curved course over the psoas muscle, and sinking into the pelvis to assume the name of rectum. The lower convolutions of the small intestine invariably fill up the superior outlet of the pelvis, and are found to a greater or less extent in that cavity, in pro portion as the bladder and rectum are empty or the reverse.
Such being the position of the parts as they appear when the anatomist lays open the ab domen in a recent subject, we proceed now to examine what parts are found in each com partment of this cavity, and the relation which they bear to each other. We may observe, in passing, that there cannot be much difference in the position of the abdominal organs during life, even in the varied attitudes of the body, from that which we find them to possess in a body recently dead. Making allowance for the pressure which is maintained upon them by the abdominal parietes, it is obvious that the position of each organ during life will be higher in the abdomen than that which it occu pies in the dead body ; all the organs are more firmly applied to one another and to the pos terior wall of the abdomen.
It is not, however, unimportant to bear in mind .that such is the nature of the contents of the hollow abdominal viscera, and such the rapidity with which they become accumulated, that changes of relation. may be rapidly effected. Thus the stomach, or any part of the intestinal canal, may by a rapid accumulation of air or any other matter within it, occupy a much more atensive portion of the abdo men than it usually does in the natural state. This is allowed by the extraordinary com pressibility of the other viscera, a com pressibility which is every day exemplified in pregnancy, aud in cases of ovarian dropsy, of ascites, &c.
1. The epigastric region.—The right extre mity of this region or the right hypochondrium is occupied almost entirely by the liver, which is connected with the diaphragm and anterior wall of the abdomen by the folds of perito neum which form what are called the ligaments of the liver. When the left lobe of the liver is raised up, we see the lesser or gastro-hepatic omentum extended between the lesser curvature of the stomach and the transverse fissure of the liver. A defined margin terminates the gastro-hepatic omentum on the right side, just adjoining the neck of the gall-bladder : if the finger be pushed underneath this margin from right to left, it passes through an opening which leads into the cavity of the omentum, and if continued downwards behind the stomach will separate the laminm of the great omentum. This opening is commonly known under the name of the Foramen of Winslow: the lesser omentum bounds it in front, behind it lie the supra-renal capsule, the vena cava ascendens, and the psoas muscle, covered by a lamina of perito neum which ascends towards the diaphragm, after having partly covered the duodenum.* The lesser splanchnic nerve will also be found in this situation lying on the quadratus lum borum muscle and on the psoas, and descend ing to throw itself into the renal plexus. On a plane posterior to the lesser omentum the inferior surface of the liver is in contact with the kidney, and with the angle of junction of the ascending and transverse portions of the colon, as is proved by the frequent adhesion of this intestine to the liver. The situation of the gall-bladder in this region demands atten tion ;—its fundus corresponds to the cartilage of the ninth rib, beneath which it sometimes projects to an extent proportionate to the de gree to which it is distended ; hence it is evi dent that an unusually distended gall-bladder is not unlikely to form a tumour below the margin of the ribs presenting all the characters of an hepatic abscess.t The gall-bladder is, in this region, in close connexion either by its neck or body, with the duodenum or tranverse colon, a fact which explains the evacuation of gall stones into either of those intestines. The left
lobe of the liver projects more or less into the central portion of the epigastric region, or that which is called the proper epigastrium. Here it is in contact by its concave surface with the anterior superior surface of the pyloric half or third of the stomach. This latter viscus when contracted lies very far back in the epigastric excavation, and extends towards the left side, so as to occupy the left hypochondrium to a great extent. Its pyloric third or half is in contact with the liver, the remaining or cardiac portion is in contact with the diaphragm ; hence it is always the displaced organ in dia phragmatic hernia. This close connexion of the stomach and diaphragm likewise explains the peculiar sonorousness which percussion frequently elicits over the left hypochondrium and even for some distance up the anterior surface of the thorax, so that when the sto mach is large and flatulent, it is often very difficult to ascertain whether the sound pro duced and heard in this region results from an effusion of air and liquid into the thorax, or from such a stomach filled partly with liquid and partly with air. When the stomach is full, the aspect of its superior surface is more directly upwards and less forwards than in the empty state ; but a considerable portion of the anterior part of this surface, as well as of the greater curvature, is in contact with the abdo minal parietes. The great curvature of the stomach for three-fifths of its extent towards the pylorus is closely connected with the upper surface of the transverse arch of the colon, and with the two anterior lamin of the great omentum which come in contact along the line of that curvature, enclosing between them the anastomosis of the gastro-epiploic arteries. IIence we sometimes find that, in cases of per foration of the stomach, the opening is filled up by the adhesion of the wall of tbe colon to the serous coat of the formerviscus, and the effusion of its contents is thereby prevented ; and it has been said that fluids may pass through an ulcer of the great curvature and be effused between the laminw of the omentum, so as to point externally as an abscess.* The extent of the relation of the stomach to the liver varies ; in some instances it extends as far outwards as the gall-bladder ; and Cruveilhier mentions a case in which gall-stones were discharged into the stomach in consequence of an adhesion formed by its anterior surface with the gall bladder. The stomach rests by its posterior and inferior surface on the superior lamina of the transverse mesocolon, which forms a natural floor to the epigastric region, and separating it from the umbilical region. Posteriorly the same lamina of the transverse mesocolon sepa rates it from the inferior transverse portion of the duodenum and from the head of the pan creas, which again are separated from the spine by the aorta and crura of the diaphragm. The lobulus Spigelii of the liver is seen behind, and to the left of the lesser curvature of the stomach, and when the latter is drawn down wards and the liver forwards, this lobe projects, pushing the gastro-hepatic omentum before it ; the lesser curvature has likewise among its connections posteriorly the cceliac axis and solar plexus, and like the great curvature has an arterial anastomosis running along it formed by the superior pyloric and gastric arteries. The spleen is very intimately connected by the gastro-splenic omentum to the left extremity or great cul-de-sac of the stomach, and seems, as it were, moulded upon it, following it in its movements, and each accompanying the other in its displacements : behind this portion of the stomach are the tail of the pancreas, the left kidney, and supra-renal capsule. The point of entrance of the cesophagus into the cardiac extremity of the stomach is overlapped by the left lobe of the liver and its left lateral ligament, and it rests upon the decussating muscular bundles of the diaphragm.t In the epigastric region we likewise find the first portion of the duodenum passing from left to right slightly upwards and backwards, terminating at the neck of the gall-bladder, with which it often contracts preternatural adhesions. Behind this superior portion of the duodenum, a little to the left of its ter mination, the ductus communis choledochus descends to enter the middle portion of this intestine, the upper part of which is likewise found in this region. Here, too, we have the upper half of the head of the pancreas, the right gastro-epiploic and the gastro-duodenalis arteries.