In proceeding to remove the parts which lie most superficially in the epigastric region, we notice on the right side the vessels and nerves enclosed between the laminw of the lesser omentum, viz. the hepatic artery and its terminal branches, the vena port, and the hepatic and cystic ducts, with the com mencement of the ductus communis *chole doehus, and entwining its filaments chiefly around the hepatic arteries is the hepatic plexus of nerves ; several lymphatic vessels of considerable size are also found here, and some lymphatic ganglions, the enlargement of which latter, wh ether acute or chronic, may retard the passage of the bile and give rise to jaundice. All these parts are invested and connected to each other by the dense cellular membrane called the capsule of Glisson. Behind the liver, and closely lodged in a groove, and sometimes a canal in its posterior thick margin, is the vena cava ascendens, which is still more intimately connected with the liver through the branches of the vena cava hepatica, which open into that portion of the ascending vein which is lodged in the groove. To the right of the vein are the supra-renal capsule and the upper part of the kidney, and to its left, and closely connected with the supra-renal capsule, is the semilunar ganglion. Here, likewise, are the renal or emulgent vessels and the renal plexus of nerves.
In the centre of the epigastric region, on removing the stomach, we open into the lesser cavity of the peritoneum, of which the stomach forms, in part, the anterior and superior boun dary. This cavity is bounded inferiorly and posteriorly by the descending layer of the trans, verse meso-colon, which covers the upper part of the pancreas; above this latter gland is the cceliac axis, surrounded .by the solar plexus of nerves, giving off its terminal branches, of which the hepatic passes towards the right side, and forwards to the transverse fissure of the liver, while the splenic directs itself tortuously towards the left side, along the upper margin of the pancreas. The pancreas itself is to be counted among the parts contained in this region ; here it is covered by the superior layer of the trans verse mesocolon, which alone separates it from the posterior surface of the stomach ; hence this gland has sometimes, by contracting an adhesion with the stomach, serVed to fill up a perfomtion by an ulcer. Behind the pan creas are the vena portm and the conflux of the splenic and superior mesenteric veins, the superior mesenteric artery, and the nervous plexus of the same name; by all of which the gland is separated from the aorta, which, again, with the pillars of the diaphragm and some lymphatic glands, separates the pancreas from the spine. To the right of the aorta, and intervening between it and the right crus, are the thoracic duct and the vena azygos, and external to each crus of the diaphragm the great splanchnic nerve is seen to connect itself with the semilunar ganglion.
On the left side the gastro-splenic omentum contains the vasa brevia and splenic arteries, the splenic plexus of nerves, and the com mencement of the left gastro-epiploic artery ; the great cul-de-sac of the stomach, and the spleen cover here the left supra-renal capsule, the semilunar ganglion and great splanchnic nerve, the upper part of the left kidney, and the renal vessels and nerves.
From the vast number and importance of the parts contained in the epigastric region, it cannot be a matter of surprise that it is fre quently the seat of disease, and that the most serious consequences will often ensue upon strong pressure or violence inflicted upon it. It is universally known that syncope may be induced or even sudden death occasioned by a blow upon the epigastrium, even in a healthy individual ; and it seems to be the favourite opinion that such results arise from the influence exerted upon the immense nervous plexus which is found here. Sometimes, however, one or more of the viscera have experienced injury, and cases of rupture of the spleen, liver, gall-bladder,.or duodenum from violence
inflicted on this region are not uncommon.s Every practitioner is familiar with the existence of epigastric pulsations, which, as they arise from a variety of causes, form a subject of great interest. Dr. Copland thus enumerates these causes, and, indeed, most of them may be deduced a priori from a knowledge of the anatomy of the region : a, nervous suscepti bility ; b, inflammation of the aorta ; c, aneu rism of the aorta; d, adhesion of the pericar diurn to the heart ; e, tumours at the root of the mesentery; j; tumours of the stomach or scirrhus of the pylorus ; g, enlargement of the pancreas ; h, hypertrophy of the heart, parti cularly of its right side ; enlargement of the inferior vena cava; k, hepatisation of the lower portion of the lungs ; /, enlargement of, or abscess in, the Event Umbilical region.—This region is distinctly and naturally separated from the epigastrium by the transverse arch of the colon and the transverse mesocolon. It is almost entirely occupied in the centre by the small intestines, and on each side by the colon, either ascending or descending. Deep seated and at the upper part of the region, we notice the inferior portion of the duodenum, which is covered by the infe rior lamina of the transverse mesocolon, and ter minates on the left side of the spine, just where the mesentery commences. The superior me senteric artery crosses above and in front of the duodenum, a few lines to the right of its termination, and when the body is laid on the back the intestine seems to suffer a constriction from the artery. Such a constriction can hardly exist during life, when the viscera of the abdo men are under the influence of the action of its walls, for then the direction of the superior mesenteric artery is so little downwards and so much forwards that it cannot_ be said to exert any pressure upon the intestine; yet it is remarkable that in many cases of ruptured intestine, the seat of the rupture has been a very short way below the continuation of the duodenum into the jejunum. The inferior portion of. the duodenum rests upon the vena cava and the aorta, and is in contact with these vessels by its posterior wall. The inferior margin of this intestine descends to very near the bifurcation of the aorta, leaving no more than from one-half to three-fourths of an inch interval. We notice, moreover, in this region the obliquity of the mesentery, the arterial and venous, nervous and lacteal ramifications existing between its lamince and the mesenteric glands or ganglions connected with the lacteals, which ganglions are often very few and much atrophied in old subjects. The convolutions of the small intestine are covered in front by the omentum, and are very closely in apposition with each other : hence they become ' matted together' by the lymph effused in peritonitis, and hence, too, in per forations, effusion of the intestinal contents by no means necessarily takes place. The looseness of the intestinal convolutions and of the mesentery by which those convolutions are tied to the spine, admits not only of their being liable to frequent introsusception, but also of being strangulated by the twisting of a knuckle of intestine. For the same reason it is that we find this intestine forming most of the hernim which protrude from the various regions of the abdomen. The small intestine occupies the whole central umbilical region, extending likewise on either side into the lum bar regions and downwards into the pelvis. Thus it forms a considerable mass interposed between the anterior and posterior abdominal walls, and it is easy to conceive how, during an irregularly distended state of the intestine, violence applied to the abdomen in front can cause a rupture of a part of it without occa sioning any solution of continuity in the wall of the abdomen.