PANCREAS. 



683 



which they are contained. It is sometimes detached from the rest of the gland, 

 and is called the lesser pancreas. 



The lesser end or tail of the pancreas is narrow; it extends to the left as far 

 as the spleen, and is placed over the left kidney and supra-renal capsule. 



The body of the pancreas is convex in front, and covered by the ascending 

 layer of the transverse mesocolon and the posterior surface of the stomach. 



The posterior surface is concave, and has the following structures interposed 

 between it and the first lumbar vertebra: the superior mesenteric artery and vein, 

 and commencement of the vena portas, the vena cava, the aorta, the left kidney, 

 supra-renal capsule, and corresponding renal vessels. 



The upper border is thick, and has resting upon it, near its centre, the coeliac 

 axis; the splenic artery and vein are lodged in a deep groove or canal in this 



Fig. 346. The Pancreas and its Relations. 



border, and, to the right, the first part of the duodenum and the hepatic artery are 

 in relation with it. 



The lower border, thinner than the upper, is separated from the transverse 

 portion of the duodenum by the superior mesenteric artery and vein ; to the left 

 of these the inferior mesenteric vein ascends behind the pancreas to join the splenic 

 vein. 



The pancreatic duct, called also the canal of Wirsung from its discoverer, extends 

 transversely from left to right through the substance of the pancreas, nearer to its 

 lower than its upper border, and lying nearer its anterior than its posterior sur- 

 face. In order to expose it, the superficial portion of the gland must be removed. 

 It commences by an orifice common to it and the ductus communis choledochus 

 upon the summit of an elevated papilla, situated at the inner side of the descending 

 portion of the duodenum, a little below its middle. Passing very obliquely 

 through the mucous and muscular coats, it separates itself from the common 

 choledoch duct, and, ascending slightly, runs from right to left through the middle 

 of the gland, giving off numerous branches, which pass to be distributed to its 

 lobules. 



Sometimes the pancreatic and common choledoch ducts open separately into the 



