Sphincter of ampulla

The sphincter of ampulla (sphincter of Oddi) is a muscular valve responsible for controlling the flow of bile and pancreatic secretions through the ampulla of Vater into the second part of the duodenum. It is composed of three layers of concentric smooth muscle that surround the common bile duct, the main pancreatic duct, and the heapatopancreatic ampulla (ampulla of Vater).

The sphincter of ampulla (of Oddi) has at least three functions:

• Prevent reflux of duodenal contents, thereby preventing the accumulation of sludge and particulate matter in the bile ducts and thus helps to reduce the risk of cholangitis.

• Regulate the flow of bile and pancreatic secretions.

• Allow retrograde filling of the gallbladder to occur

The sphincter of ampulla (sphincter of Oddi) is one of the complex of four smooth muscle sphincters composing the hepatopancreatic ampulla (ampulla of Vater):

• Sphincter of ampulla (hepatopancreatic sphincter; sphincter of Oddi).

• Sphincter of the pancreatic duct (of Boyden)

• The two muscles composing the sphincter of the bile duct (sphincter of choledocus)

  • Superior sphincter of bile duct

  • Inferior sphincter of bile duct