Male Duodenojejunal Flexure of the Intestine

Description

Arcing across the upper abdomen, the duodenojejunal flexure (flexura duodenojejunalis) marks the transition from the ascending (fourth) part of the duodenum to the first jejunal loop. The junction sits left of the midline at about the level of L2, posterior to the transverse colon and its mesentery, where the retroperitoneal duodenum becomes intraperitoneal jejunum. Suspensory fibers of the ligament of Treitz (musculus suspensorius duodeni) attach to the duodenojejunal angle and course superiorly toward the right crus of the diaphragm and adjacent connective tissue near the celiac axis. This location is a radiologic and operative landmark, because the duodenojejunal junction defines the proximal limit of the jejunum on contrast studies and helps confirm normal intestinal rotation. Failure to place this flexure in the left upper quadrant raises concern for malrotation and midgut volvulus, and its tethering effect is also discussed in superior mesenteric artery syndrome, where the third part of the duodenum may be compressed between the SMA and aorta. Surgeons use the ligament of Treitz to orient bowel runs and to distinguish proximal from distal small bowel during trauma laparotomy, adhesiolysis, or when selecting a Roux limb. Useful for gross anatomy teaching of the foregut to midgut transition, this illustration also supports radiology modules on upper GI series interpretation and surgical education on upper abdominal landmarks. It fits well in textbooks, operative atlases, and patient education materials that explain the duodenojejunal angle and ligament of Treitz in clear anatomical context. Anatomical accuracy verified by SciePro's Medical Advisory Board.