THE BILE DUCT 



263 



(p. 264) and they may also tend to obstruct the inferior vena 

 cava, which lies behind it. 



At its lower end the bile duct pierces the muscular wall of 

 the duodenum very obliquely and opens into a small space, 

 termed the ampulla of Vater (Fig. 98), which lies in the 

 submucous tissue. The main duct of the pancreas (p. 269) 



FIG. 98. Diagram of the Bile Duct and the Pancreatic Ducts, 

 showing how they open into the Duodenum. 



i. Gall bladder. 



2 Right hepatic duct. 



3. Bile duct. 



4. Wall of duodenum. 



5. Ampulla of Vater. 



6. Accessory pancreatic duct. 



7. Pancreatic duct. 



8. Communication between 6 and 7. 



also opens into the ampulla, which possesses a single small 

 opening into the interior of the duodenum. Owing to the 

 obliquity with which the duct pierces the duodenal wall, gall- 

 stones may become impacted before they reach the ampulla of 

 Vater. In this case they are not so likely to obstruct the 

 pancreatic duct, but they may do so if they succeed in entering 

 the ampulla and are unable to pass through the small orifice 

 into the duodenum. 



