Duodenojejunal flexure

Last revised by Assoc Prof Craig Hacking on 13 Oct 2022

The duodenojejunal (DJ) flexure or junction is the anatomical border between the duodenum and the jejunum.

The duodenojejunal flexure is located anterolateral to the aorta at the level of the upper border of the second lumbar vertebra. It makes a sharp turn anteroinferiorly to become the jejunum.

The duodenojejunal flexure is suspended from the ligament of Treitz, which serves as its surgical landmark and gives it its unique shape. It also marks the small bowel's transition from the retroperitoneum, which invests the duodenum, into the peritoneal cavity.

  • venous anatomy not well characterized
  • veins accompany arteries of corresponding names and may drain directly into the superior mesenteric vein

For uncommon variant anatomy of the duodenojejunal flexure, see

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Cases and figures

  • Case 1: normal position of the DJ flexure
    Drag here to reorder.
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