Location and Relations
The flexure is located to the left of the vertebral column at the level of the 2nd and 3rd lumbar vertebrae, directly beneath the root of the transverse mesocolon (mesocolon transversum).
Topographically, the flexure is closely related to the following structures:
- Root of the mesentery (radix mesenterii) — originates near the flexura duodenojejunalis and extends obliquely downward and to the right toward the right iliac fossa, crossing anteriorly over the terminal duodenum, abdominal aorta, inferior vena cava, right ureter, and psoas major muscle.
- Inferior mesenteric vein (v. mesenterica inferior) — runs to the left of the flexure beneath the body of the pancreas before draining into the splenic vein.
Suspensory Apparatus and Treitz Recess
Fixation of the flexure is maintained by the suspensory ligament of Treitz (lig. suspensorium duodeni), formed by a peritoneal fold covering the suspensory muscle of the duodenum (m. suspensorius duodeni). The muscle originates from the circular muscular layer of the intestine at the flexure, travels superiorly behind the pancreas, expands in a fan-like fashion, and blends into the fascia and muscular fibers of the left crus of the diaphragm.
A peritoneal recess—the duodenojejunal recess (recessus duodenojejunalis, or Treitz recess)—is formed near the flexure. Its walls are bounded by:
- Anteriorly — the plica duodenojejunalis (peritoneal fold between the flexure and the root of the mesocolon transversum).
- Posteriorly — the parietal peritoneum of the posterior abdominal wall.
- Superiorly — the transverse mesocolon.
- Inferiorly — the superior margin of the flexure.
Blood Supply
The flexura duodenojejunalis is supplied by:
- Anterior inferior pancreaticoduodenalis artery (a. pancreaticoduodenalis inferior anterior).
- Posterior inferior pancreaticoduodenalis artery (a. pancreaticoduodenalis inferior posterior).
- First jejunal artery.
Clinical and Surgical Significance
The flexure serves as a critical anatomical landmark in abdominal surgery:
- Locating the origin of the small intestine (Gubarev maneuver): To find the flexure, the surgeon grasps the greater omentum and transverse colon, retracts them superiorly, and sweeps the fingers of the right hand along the root of the transverse mesocolon toward the spine, sliding leftward to capture the first fixed loop of the small intestine.
- Bowel exploration: Small bowel examination begins at the flexura duodenojejunalis, inspecting each loop sequentially along its antimesenteric and mesenteric borders. If a lesion is found, it is not immediately closed; instead, the loop is wrapped in a moist sponge, secured with a soft atraumatic clamp, and exploration continues.
- Witzel jejunostomy: In cases of advanced gastric cancer or chemical gastric burns where gastrostomy is impossible, a loop of the jejunum is selected 40–50 cm distal to the duodenojejunal flexure for feeding tube placement.
- Treitz hernia: Pathological enlargement of the Treitz recess (recessus duodenojejunalis) can form a hernial sac, leading to an internal internal hernia.