1194 DIGESTIVE SYSTEM 



small intestine. Upon this surface are also the pancreatico-duodenal and (in 

 part) the superior mesenteric vessels. The margin of the head of the pancreas is 

 C-shaped, corresponding to the inner aspect of the duodenal loop, with which it 

 is closely related. Superiorly the margin is in contact with the pylorus and first 

 part of the duodenum; on the right, with the descending duodenum and the ter- 

 minal portion of the common bile duct; inferiorly, with the horizontal, and on the 

 left, with the terminal ascending portion of the duodenum. 



The lower and left portion of the head of the pancreas is hooked around behind 

 the superior mesenteric vessels, forming the processus uncinatus or pancreas of 

 Winslow (fig. 922). A groove, the pancreatic notch [incisura pancreatis], is thus 

 formed for the vessels. The morphology of this process is explained later under 

 development (fig. 958). 



In the adult condition, the head of the pancreas is largely retroperitoneal. 

 The only portions covered by peritoneum are (1) a small area above the attach- 

 ment of the colon, and in relation with a pocket-like recess of the bursa omentalis, 

 and (2) a small area below the transverse colon, which is in relation with coils of 

 small intestine. The mesentery of the small intestine begins where the superior 

 mesenteric vessels pass downward from in front of the processus uncinatus. 



The junction of the upper and left aspect of the head with the body of the 

 panel eas is called the neck. This is a somewhat constricted portion grooved 

 posteriorly by the superior mesenteric vessels, the vein here joining with the splenic 

 to form the portal vein (fig. 955). Anterior to the neck is the pyloric portion of 

 the stomach. The upper portion of the neck (together with a variable area on the 

 left end of the body) projects above the lesser curvature of the stomach. This 

 projection [tuber omentale] is related, through the lesser omentum, with a similar 

 tuberosity on the left lobe of the liver. The anterior aspect of the neck is covered 

 with peritoneum of the bursa omentalis (lesser sac), and is continuous with the 

 anterior surface of the body of the pancreas (fig. 922). 



The body [corpus pancreatis] is the triangularly prismatic portion of the pan- 

 creas extending from the neck on the right to the tail on the left. Its direction is 

 transversely to the left and (usually) somewhat upward. It is therefore usually 

 placed at a somewhat higher level than the head, opposite the first lumbar verte- 

 bra. It presents three surfaces — ^anterior, posterior, and inferior — and three 

 borders— superior, anterior, and posterior. 



Of the surfaces, the anterior [facies anterior] faces forward and somewhat 

 upward. It is covered with the peritoneum of the posterior wall of the bursa 

 omentalis (lesser sac), and forms a slightly concave area which is in contact with 

 the posterior surface of the stomach (figs. 904, 906). The posterior surface [f. 

 posterior] of the body of the pancreas is flattened and retroperitoneal. From right 

 to left it crosses the anterior aspect of aorta, left suprarenal body and left kidney. 

 The splenic vessels also run along the posterior surface, the artery, which is above, 

 corresponding more nearly with the superior border. The inferior surface [f. 

 inferior] is usually the narrowest of the three. It is covered by peritoneum (con- 

 tinuous with the lower layer of the transverse mesocolon) and is in contact with 

 the duodeno-jejunal angle medially and with coils of jejunum laterally. 



Of the borders, the superior [margo superior] is related with the splenic artery 

 along its whole length from its origin in the ccEliac, and the posterior [margo 

 posterior] separates posterior and inferior surfaces. The anterior border [margo 

 anterior] is sharp and prominent. It gives attachment to the transverse meso- 

 colon, whose upper layer (belonging to the lesser sac) is continuous with that on 

 the anterior surface of the pancreas, and whose lower layer (belonging to the 

 greater sac) is continuous with that on the inferior surface. 



The tail of the pancreas [cauda pancreatis] is at the left extremity of the body. 

 It is variable in form, but usually somewhat blunted and upturned. It is almost 

 invariably in contact laterally with the medial aspect of the spleen, and inferiorly 

 with the splenic flexure of the colon. The splenic vessels often cross from above 

 in front of the tail of the pancreas on their way to join the spleen. 



Ducts. — The pancreas has usually two ducts, the main pancreatic duct and the 

 accessory duct. The main pancreatic or duct of Wirsung [ductus jjancreaticus; 

 Wirsungi] begins in the tail of the ])ancreas, and extends to the right within the 

 body of the pancreas, about midway between upi)er and posterior borders, but 

 nearer the posterior surface (figs. 922, 957). It runs a slightly sinuous course 



