point along the course of the gastrointestinal tract where the duodenum ends and the jejunum begins; occurs approximately at the level of the L2 vertebra, 2-3 cm to the left of the midline; usually takes the form of an acute angle, the duodenojejunal flexure, and is supported by the attachment of the suspensory muscle (ligament) of the duodenum.duodenojejunal flexure.