Duodenojejunal Flexure of the Male Small Intestine

Description

Centered on the duodenojejunal junction, the duodenojejunal flexure marks the abrupt transition from the ascending (fourth) part of the duodenum to the proximal jejunum in an anterior view of the male abdomen. The flexure sits left of the midline at approximately the L2 level, posterior to the transverse colon and its mesocolon and just inferior to the body of the pancreas. The suspensory ligament of the duodenum (ligament of Treitz) is shown tethering the flexure superiorly and posteriorly toward the right crus of the diaphragm. A sharp, fixed angle. Recognition of this landmark matters because it is the practical border between foregut and midgut, with implications for arterial supply (superior pancreaticoduodenal branches of the gastroduodenal artery versus jejunal branches of the superior mesenteric artery) and lymphatic drainage patterns. Surgeons and radiologists use the position of the duodenojejunal flexure to judge intestinal rotation, and abnormal location supports the diagnosis of malrotation and potential midgut volvulus. Its fixation by Treitz also explains why obstruction proximal to this point behaves differently than a more distal small-bowel obstruction, and why the angle can be distorted by pancreatic or retroperitoneal processes. Educators will find this asset well suited for gross anatomy labs, GI block teaching on embryologic rotation and mesenteric attachments, and exam figures that require a clean definition of the duodenojejunal angle. Publishers can pair it with diagrams of SMA territory, upper GI contrast studies identifying the ligament of Treitz, or surgical discussions of duodenal mobilization (Kocher maneuver) and jejunal anastomosis planning. Anatomical accuracy verified by SciePro's Medical Advisory Board.