26 PANCREAS SPLEEN. 



THE PANCREAS. 



The pancreas is a long, flattened, conglomerate gland, analogous to the 

 salivary glands. It is about six inches in length, and between three ind 

 four ounces in weight ; is situated transversely across the posterior wall 

 of the abdomen, behind the stomach, and resting on the aorta, vena portse, 

 inferior vena cava, the origin of the superior mesenteric artery, and the left 

 kidney and supra-renal capsule ; opposite the first and second lumbar 

 vertebrae. It is divided into a body, a greater and a smaller extremity : 

 the great end or head is placed towards the right, and is surrounded by 

 the curve of the duodenum ; the lesser end extends to the left as far as 

 the spleen. The anterior surface of the body of the pancreas is covered 

 by the ascending posterior layer of peritoneum, and is in relation with the 

 stomach, the first portion of the duodenum, and the commencement of the 

 transverse arch of the colon. The posterior surface is grooved for the 

 splenic vein, and tunnelled by a complete canal for the superior mesenteric 

 and portal vein, and superior mesenteric artery. The upper border pre- 

 sents a deep groove, sometimes a canal, for the splenic artery and vein, 

 and is in relation with the oblique portion of the duodenum, the lobus 

 Spigelii, and cceliac axis. And the lower border is separated from the 

 transverse portion of the duodenum by the superior mesenteric artery and 

 vein. Upon the posterior part of the head of the pancreas is a lobular fold 

 of the gland which completes the canal of the superior mesenteric vessels, 

 and is called the lesser pancreas. 



In structure, the pancreas is composed of reddish-yellow polyhedral 

 lobules ; these consist of smaller lobules, and the latter are made up of the 

 arborescent ramifications of minute ducts, terminating in ca3cal pouches. 



The pancreatic duct commences at the papilla on the inner and posterior 

 surface of the perpendicular portion of the duodenum by a small dilatation 

 which is common to it and the ductus communis choledochus, and, pass- 

 ing obliquely between the mucous and muscular coats, runs from right to 

 left through the middle of the gland, lying nearer its anterior than its pos- 

 terior surface. At about the commencement of the apicial third of its 

 course it divides into two parallel terminal branches. The duct gives off 

 numerous small branches, which are distributed through the lobules, and 

 constitute, with the latter, the substance of the gland. The duct which 

 receives the secretion from the lesser pancreas is called the ductus pancre- 

 aticus minor; it opens in the principal duct near the duodenum, and some- 

 times passes separately into that intestine. As a variety, two pancreatic 

 ducts are occasionally met with. 



Vessels and Nerves. The arteries of the pancreas are branches of the 

 splenic, hepatic, and superior mesenteric ; the veins open into the splenic 

 vein ; the lymphatics terminate in the lumbar glands. The nerves are fila- 

 ments of the splenic plexus. 



THE SPLEEN. 



Ine spleen is an oblong flattened organ, of a dark bluish-red colour, 

 situated in the left hypochondriac region. It is variable in size and weight, 

 spongy and vascular in texture, and exceedingly friable. The external 

 surface is convex, the internal slightly concave, indented along the middle 

 line, and pierced by several large and irregular openings for the entrance 



