Anatomical Position of the Right Ascending Part of the Male Duodenum, Lateral View

Description

Shown in right lateral profile, the ascending (fourth) part of the duodenum is positioned superior to the horizontal (third) part and continues proximally from the duodenojejunal flexure toward the jejunum, lying to the right of the midline structures that it will ultimately approach. Its wall is represented with mucosa and luminal folds internally, a submucosal layer, and a muscularis externa with inner circular and outer longitudinal smooth muscle, consistent with small-bowel anatomy. The terminal limb of the duodenum sits posterior to the anterior abdominal wall and anterior to retroperitoneal planes, a relationship that explains why subtle changes in fixation can alter its contour on lateral views. For surgeons and radiologists, this segment matters because the duodenojejunal junction acts as a fixed point against which small-bowel mobility is judged, and the ascending duodenum is closely tied to the ligament of Treitz and the root of the mesentery. Malrotation, paraduodenal hernia, or adhesive kinking can present with obstruction near this transition, and a lateral depiction helps clarify why the fourth part can be compressed or angulated as it ascends. Short and tight. That mechanical concept is hard to teach without a clean profile. Use this artwork for GI anatomy teaching in medical and PA curricula, for operative atlases describing mobilization of the duodenum (Kocher maneuver context and limits), or for radiology publications correlating the distal duodenum with upper GI contrast studies and CT enterography landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.