THE PANCREAS. 523 



The Biliary ducts are, the ductus communis choledochus, the 

 cystic and the hepatic duct. 



The Ductus communis choledochus (%oX>) bilis, Se^o^ou recipio) is 

 the common excretory duct of the liver and gall-bladder ; it is about 

 three inches in length, and commences upon the papilla, situated on 

 the inner side of the cylinder of the perpendicular portion of the 

 duodenum. Passing obliquely between the mucous and muscular 

 coats, it ascends behind the duodenum, and through the right border 

 of the lesser omentum ; and divides into two branches, the cystic 

 duct and the hepatic duct. It is constricted at its commencement 

 in the duodenum, and becomes dilated in its progress upwards. 



The Cystic 'duct, about an inch in length, passes outwards to the 

 neck of the gall-bladder, with which it is continuous. 



The Hepatic duct continues onwards to the transverse fissure of 

 the liver, and divides into two branches, which ramify through the 

 portal canals to every part of the liver. 



The coats of the hepatic ducts are an external or fibrous, and an 

 internal or mucous. 



The external coat is composed of a contractile fibrous tissue, 

 which is probably muscular ; but its muscularity has not yet been 

 demonstrated in the human subject. The mucous coat is continuous 

 on the one hand with the lining membrane of the hepatic ducts and 

 gall-bladder, and on the other with that of the duodenum. 



Vessels and Nerves. The gall-bladder is supplied with blood by 

 the cystic artery, .a branch of the hepatic. Its veins return their 

 blood into the portal vein. The nerves are derived from the hepatic 

 plexus. 



* 



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 or four ounces in weight, and is situated transversely across 

 the posterior wall of the abdomen, behind the stomach, and resting 

 upon the aorta, vena portse, inferior vena cava, the origin of the 

 superior mesenteric artery, and the left kidney and supra-renal 

 capsule ; opposite to 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 the 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 pos- 

 terior surface is grooved for the splenic vein, and tunneled by a 

 complete canal for the superior mesenteric and portal vein, and 

 for the superior mesenteric artery. The upper border presents a 

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

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



