Duodenum

DigestiveOrgansAbdomen

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What it is

First part of the small intestine: a C-shaped loop in four parts (superior, descending, horizontal, ascending) wrapped around the head of the pancreas, mostly fixed to the back wall of the abdomen.

Function

Receives chyme from the stomach plus bile and pancreatic juice through the major duodenal papilla in its descending part, neutralising the acid and starting most chemical digestion.

Size

About 25 cm long and 3-4 cm wide; the flexure where it becomes the jejunum lies left of L2.

Clinical note

Its name means "twelve finger-breadths". Most peptic ulcers occur in its first 2-3 cm, the duodenal bulb.