Posterior Position of the Intermediate Lateral Flexure of the Male Rectum

Description

Posteriorly oriented, the intermediate lateral flexure (Kohlrausch fold, plica transversalis media) is shown as a transverse mucosal shelf projecting into the lumen of the rectal ampulla, offset to the left lateral wall in the adult male. The sacrum and coccyx lie immediately posterior to the rectum, while the anal canal continues inferiorly toward the pelvic floor. Proximally, the rectum transitions toward the sigmoid colon, and distally the ampulla narrows as it approaches the anorectal junction. Recognition of this middle rectal fold matters because it is a consistent internal landmark when you correlate endoscopic appearance with pelvic anatomy and when you teach the anteroposterior and lateral curvatures of the rectum. The flexure contributes to the physiologic shelving that can trap fecal material and is often referenced when discussing defecatory disorders and rectal intussusception patterns. It also helps orient the examiner during digital rectal examination and rigid proctoscopy, where a left-sided transverse fold can be mistaken for a pathologic ridge if you do not expect it. Suitable for colorectal anatomy lectures, proctology and gastroenterology teaching files, and atlas plates describing the rectal ampulla and its plicae transversales, this posterior view supports clear labeling for students learning Terminologia Anatomica and for authors illustrating endoscopic landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.