Rotation of the Pancreatic & Biliary Ducts
final arrangement of the biliary and pancreatic ducts
In two diagrams.
Top Diagram
- The abdominal accessory digestive organs arise as outgrowths of the foregut, prior to stomach and duodenal rotation.
- The dorsal pancreatic bud extends dorsally.
- The ventral pancreatic bud, gallbladder, and liver buds (aka, hepatic diverticulum) extend ventrally.
- The liver buds develop as an outgrowth of the foregut into the septum transversum.
The connection between the liver buds and foregut narrows to form the bile duct; the bile duct then gives rise to its own outgrowth, which becomes the gallbladder and cystic duct.
- The proximal duodenum rotates clockwise.
By week 11, rotation is complete, and the organs are in their final locations.
- The ventral and dorsal pancreatic buds and their ducts fuse.
- The complete pancreas nestles into the c-curve of the duodenum and extends towards the left side of the body.
- The uncinate process is the portion derived from the ventral pancreatic bud.
- The main pancreatic duct, which drains smaller ducts and empties into the duodenum via the major papilla.
- The accessory pancreatic duct drains via the minor papilla. In many individuals, this structure degenerates and is absent in the adult.
- The bile and pancreatic ducts join to drain bile and pancreatic juices at the major papilla.
- The liver drains bile into the hepatic duct.
- The gallbladder drains bile into the cystic duct;
- The hepatic and cystic ducts merge to form the common bile duct.
- Because of the rotation of the foregut and the displacement of the papillae, the common bile duct wraps posteriorly around the duodenum;
- It joins with the main pancreatic duct to drain bile at the major papilla to the duodenum.
- Thus, the major papilla provides an entryway for both bile and pancreatic juices.