Colon of a Male With Colorectal Cancer, Posterior View

Description

Posterior anatomy of the male lower abdomen and pelvis is rendered with the large bowel traced in semi-transparent pink from the ascending colon on the patient’s right, across the transverse colon, then inferiorly along the left-sided descending colon into the sigmoid colon and rectum in the midline. A prominent mass expands from the sigmoid segment, positioned left and inferior to the transverse colon and anterior to the sacrum and posterior abdominal wall. The rectum continues inferiorly within the pelvic cavity, where its posterior relationship to the presacral space and sacral curvature becomes evident. Orientation is clear. Sigmoid colorectal cancer often declares itself late, and posterior extension has direct implications for T stage and resectability because tumor penetration beyond the muscularis propria can tether the bowel to retroperitoneal fascia, the presacral plane, or adjacent pelvic structures. A posterior perspective helps you think in operative planes: mobilization along the left paracolic gutter, protection of retroperitoneal structures (including the ureter coursing anterior to the iliac vessels), and the importance of an intact mesocolic or mesorectal envelope when disease approaches the posterior body wall. It also frames common patterns of spread, from regional lymphatics along the inferior mesenteric vessels to possible peritoneal reflection involvement near the rectosigmoid junction. Use this artwork in colorectal surgery and oncology teaching to introduce anatomic staging, posterior surgical access, and why posterior fixation can complicate sigmoid colectomy or low anterior resection planning. It also fits pathology atlases, patient education handouts about left-sided bowel cancer, and conference slides discussing cross-sectional correlation with CT or MRI for local invasion. Anatomical accuracy verified by SciePro's Medical Advisory Board.