1188 



DIGESTIVE SYSTEM 



The ductus choledochus or common bile-duct is about 7.5 cm. in length and 

 6 mm. in width. It passes down between the layers of the lesser omentum, in 

 front of the portal vein, and to the right of the hepatic artery (fig. 946) ; it then 

 passes behind the first part of the duodenum, then between the second part and the 

 head of the pancreas, being almost completely embedded in the substance of the 

 pancreas, and ends a little below the middle of the descending duodenum by open- 

 ing into that part of the intestine on its left side and somewhat behind (figs. 921, 



Fig. 949. 



-Interior of the Gall Bladder and Ducts. (From Toldt's Atlas.) 

 Tunica mucosa of gall bladder 



Plies tunics mucosa 



Spiral valve (of Heister) 



Common bile duct (ductus choledochus) 



Biliary mucous glands 



922, 957). It pierces the intestinal wail very obHquely, running between the 

 muscular layers for a distance of about 1 to 2 cm. There is a slight constriction 

 at its termination. The pancreatic duct is generally united with the ductus 

 choledochus just before its termination, and there is a slight papilla at their place 

 of opening on the mucous surface of the duodenum. This papilla is about 8 or 

 10 cm . from the pylorus. After the pancreatic duct has entered the bile-duct there 

 is (in about half the cases) a dilatation of the common tube called the ampulla of 

 Vater. 



