Ascending part

The ascending part of duodenum (Pars ascendens duodeni) is the terminal segment of duodenum. It is very long in Ruminants and Rabbits, somewhat shorter in Carnivores, it is short in Humans and barely formed in Equids. In all species it lies to the left of the mesenteric root, reaching the ventral surface of the left kidney or its vicinity, and, attached to the lumbar region by a narrow mesentery, ends at the duodenojejunal flexure (Flexura duodenojejunalis), generally abrupt and oriented ventro-caudally.