Anatomical Presentation of the Lateral Flexure of the Male Rectum

Description

Oblique lateral anatomy of the adult male rectum emphasizes the lateral rectal flexure as the rectal ampulla transitions superiorly into the rectosigmoid junction. The rectum courses inferiorly and anteriorly from the level of S3, conforming to the sacral concavity (flexura sacralis recti) before angling toward the pelvic floor. Posteriorly, the sacrum and coccyx frame the rectal curve, while anterior relationships commonly include the prostate and seminal vesicles separated from the anterior rectal wall by Denonvilliers’ fascia. Small but readable changes in caliber are apparent from the rectosigmoid curve to the ampulla. Orientation of the rectal curvatures matters when you pass instruments. During flexible sigmoidoscopy or colonoscopy, the rectosigmoid junction and sacral flexure are frequent points of looping and patient discomfort, and recognizing the expected lateral bend helps guide torque, withdrawal, and repositioning. The same landmarks guide surgical planning for low anterior resection and total mesorectal excision, where pelvic curvature, proximity to the prostate, and the distal reach toward the anorectal junction influence stapler angle and safe dissection planes. A practical teaching point. Ideal for anatomy and colorectal surgery teaching in pelvic anatomy blocks, endoscopy training materials, and procedural atlases that discuss scope navigation across the rectosigmoid curve and into the rectal ampulla. Editors will also find it useful for urology and proctology texts when explaining anterior rectal relations in the male pelvis and the role of Denonvilliers’ fascia in separating rectum from prostate. Anatomical accuracy verified by SciePro's Medical Advisory Board.