1070 



THE ORGANS OF DIGESTION. 



over the narrow inferior surface (Fig. 679). Thus the posterior surface is devoid 

 of peritoneum. 



The tail of the pancreas rests upon the lower part of the inner surface of the 

 spleen, or is bound to it by a fold of peritoneum, the lig. pancreatico-lienale. It 

 crosses over the middle of the left kidney, or kidney and capsule, or capsule 

 alone. In front of this portion is the left gastro-epiploic artery. 



The excretory duct of the gland, ductus pancreaticus or canal of Wirsung runs 

 (1643) from left to right in the long axis of the gland, sometimes approaching 

 the anterior surface, but more often the posterior surface. It begins with a very 

 small calibre, formed by union of small ducts from the lobules, in the tail part, 

 and gradually increases in size on the receipt of tributaries from every side ; so 

 that near its mouth it attains the size of the classical quill, about one-ninth of an 

 inch in diameter. It can be found by its white color and close relation to the 

 large pancreatic artery. After reaching the neck it turns downward, backward, 

 and to the right in the head, and reaches the left side of the common bile-duct, 

 and both go to the descending duodenum. 



It receives numerous branches in the head of the gland, a large one from 

 below, and the ductus pancreaticus accessorius or ductus Santorini from above 

 (1775) (Fig. 682). 



This latter duct opens into the duodenum independently on a papilla about 

 one inch above the orifice of the others. 1 The usual course of its contents, how- 



FIG. 682. Pancreas and duodenum from behind. The pan- 

 creatic duct is dissected free and the posterior wall of the du- 

 odenum removed. (Henle.) 



Ductus 

 choledochus Wa u of duodenum 



Fold of mucous 

 membrane 



Diverticuhtm Vateri 

 Papilla Vateri 



FIG. 683. Section of duodenal wall 

 through the papilla on which the bile 

 and pancreatic ducts open. (Henle.) 



ever, is below into the pancreatic duct. Should this become occluded near its 

 orifice then a reverse flow might occur in the duct of Santorini. 



The bile and pancreatic ducts do not unite outside the duodenal wall. They 

 enter it obliquely and run obliquely a short distance between its coats and then 

 unite at an acute angle and empty into a common receptacle just under the 

 mucous membrane (Fig. 683). This little bladder-like pouch is called the diver- 

 ticulum Vateri (1720). It throws up a papilla of mucous membrane situated on 

 the free edge of one of the valvulae conniventes. This is the papilla of Voter. 

 It has a single opening, which can be best found by the presence of a drop 

 of fluid intruded by pressure on the gall-bladder or pancreas. The papilla 

 is still farther concealed by a mucous fold, which covers it from above 

 (Fig. 683). 



Abnormal forms occur ; the descending duodenum mny be surrounded by a 

 ring of pancreatic tissue ; the tail may be bifid ; a part of the head curving 

 around behind the mesenteric vessels may form the lesser pancreas. Accessory 

 glands (pancreas accessorium) are found most often in the walls of the jejunum 

 and in those of the stomach. 



1 This is of interest, as the pancreas originally budded from the duodenum as two outgrowths. 

 At about the sixth week the processes and their ducts join, as here seen. 



