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Rotation of the Pancreatic & Biliary Ducts

Biliary and Pancreatic Duct Rotation

Let's see how rotation of the stomach and proximal duodenum determine the final arrangement of the biliary and pancreatic ducts.

Abdominal accessory organs arise as outgrowths of the foregut, as follows:

The dorsal pancreatic bud extends dorsally; the ventral pancreatic bud, gallbladder, and hepatic bud (aka, hepatic diverticulum) extend ventrally.

The hepatic bud develops as an outgrowth of the foregut into the septum transversum; the connection between the hepatic bud and foregut narrows to form the bile duct. The bile duct gives rise to its own outgrowth, which becomes the gallbladder and cystic duct.

As the stomach rotates clockwise, it swings the proximal duodenum to the right, bringing the ventral pancreatic bud posteriorly toward the dorsal pancreatic bud.

By week 8, rotation is mostly complete, and the organs are in their final locations.

The ventral and dorsal pancreatic buds and their ducts fuse, and the bile and pancreatic ducts join to drain bile and pancreatic juices at the major papilla.

The fused 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 and accessory pancreatic ducts, which drain smaller ducts and empty into the duodenum.

On the right side of the diagram, the liver drains into the hepatic duct, and the gallbladder drains into the cystic duct; the hepatic and cystic ducts merge to form the common bile duct.

The rotation of the foregut displaces its connection with the bile and pancreatic ducts, so, now, the common bile duct travels posteriorly around the duodenum, where it joins with the main pancreatic duct to drain bile into the duodenum.

In our notes, you can learn about the papillae that drain bile from the ducts to the interior of the duodenum.

Annular pancreas

An annular pancreas forms when the left portion of the ventral pancreatic bud migrates counterclockwise, while the right portion rotates clockwise (the normal direction).

Consequently, the proximal duodenum becomes wrapped in pancreatic tissue, which can cause constriction and obstruct passage of duodenal contents.

Rotation of the Pancreatic & Biliary Ducts

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