The duodenojejunal flexure or duodenojejunal junction, also known as the angle of Treitz,[1][2] is the border between the duodenum and the jejunum.
Structure
The ascending portion of the duodenum ascends on the left side of the aorta, as far as the level of the upper border of the second lumbar vertebra. At this point, it turns abruptly forward to merge with the jejunum, forming the duodenojejunal flexure. This forms the beginning of the jejunum.[3] The duodenojejunal flexure is surrounded by the suspensory muscle of the duodenum.[4]: 274 It is retroperitoneal, so is less mobile than the jejunum that comes after it, helping to stabilise the jejunum.[5]
^Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN978-0-8089-2306-0.