The Pancreas, about 6 inches long, runs almost horizontally across the abdomen at the level of the first lumbar vertebra, about 3 inches above the umbilicus. The tail is in contact with the spleen ; the body is prismatic in shape, one edge pointing anteriorly ; while at the attenuated neck the organ describes a semicircle, so that the head is directed downwards and to the left, being lodged in the concavity formed by the loop of the duodenum. In front the head is in relation to the transverse colon, and behind to the vena cava, renal vessels, and aorta. The uncinate process of the head is sometimes separate, forming the lesser pancreas. The neck is narrow, lies in front of the portal vein, and presents a notch on the left side at its junction with the head, through which the superior mesenteric vessels pass, separating the head and neck from the duodenojejunal flexure. The posterior surface of tlie body has no peritoneal covering, but is attached by areolar tissue to the posterior abdominal wall and the organs lying on it-namely, aorta, and origin of superior mesenteric artery, left renal vessels, left suprarenal capsule, and left kidney. The splenic artery (with the vein below it) runs behind the upper border of the pancreas. The upper surface of the body presents a small projection, the tuber omentale, at its junction with the neck. This upper surface is covered by the posterior layer of .the lesser peritoneal sac, which separates it from the stomach which rests on it. The inferior surface is covered by descending peritoneum derived from the transverse mesocolon, and is in contact with the duodeno-jejunal flexure, small intestine, and splenic flexure of the colon. The pancreatic duct (of Wirsung) runs almost from the tail forward, till, on reaching the neck, it meets the bile-duct and opens, as already described, about 4 inches beyond the pylorus. It receives many branches in its course, and frequently an accessory duct (of Santorini) opens into the duodenum § inch above the main duct, with which it previously anastomoses. The blood-supply is derived from the superior and inferior pancreatico-duodenal arteries (from the gastro-duodenal and superior mesenteric respectively), inferior pancreatic (from either gastro-duodenal or superior mesenteric), and branches from splenic and hepatic arteries. The veins open into the superior mesenteric, portal, and splenic veins. The lymphatics pass to the cceliac glands, and the nerves are derived from the solar plexus, through the superior mesenteric, cceliac, and splenic plexuses.
In addition to secreting the pancreatic juice for digestion of carbohydrates, the pancreas is supposed to supply an ' internal secretion,' the destruction of the pancreas by disease giving rise to pancreatic diabetes. Owing to its important functions, obscurity of its pathological phenomena, and to its difficult position, the pancreas has not been much subjected to surgical interference. Recently attention has frequently been called to pancreatitis, sometimes giving rise to suppuration, and necessitating surgical interference to prevent peritonitis. Pancreatic cysts occasionally arise from obstruction of the duct, from a calculus or pressure on it from without. The cyst generally commences in the tail, and as it increases in size presents between stomach and transverse colon, pushing the great omentum before it. Such cysts sometimes attain a very large size. Both cysts and abscesses are generally best reached by a median incision above the umbilicus, and then opening through the omentum. Carcinoma not infrequently occurs in the head, rapidly involving the pancreatic and bile ducts, and pressing on the portal vein, pylorus, and other surrounding parts. Removal by operation is generally out of the question. Rarely it has been found in a diaphragmatic hernia, or sloughed off after having been invaginated into the sac. Attempts have been made in cases of pancreatic diabetes to implant portions of healthy pancreatic tissue in the subcutaneous tissues.