Anatomical Steps of the Sigmoidectomy Procedure

Description

Running from the cecum in the right lower quadrant to the rectum in the midline pelvis, the large intestine is presented as a continuous tube with the ascending colon rising superiorly to the hepatic flexure, the transverse colon crossing the upper abdomen, and the descending colon tracking inferiorly along the left flank. Inferior and anterior to the descending segment, the sigmoid colon forms the characteristic S-shaped loop before continuing distally as the rectum and anal canal. The sigmoid sits inferior to the transverse colon and medial to the left lateral abdominal wall, a mobile segment that bridges the fixed descending colon and the pelvis. Sigmoidectomy most often targets disease concentrated in this distal colonic segment, classically diverticulitis with recurrent inflammation, stricture, fistula, or perforation, but also obstructing carcinoma at the sigmoid-descending junction. Orientation matters: the inferior mesenteric vessels and their branches supply the left colon, and the left ureter and gonadal vessels course retroperitoneally posterior to the sigmoid mesocolon, where they are at risk during mobilization and ligation. Clear depiction of proximal and distal transection points supports teaching of a tension-free colorectal anastomosis and the logic of resecting to healthy, well-perfused bowel. Surgical educators use this type of stepwise sigmoidectomy diagram in general surgery and colorectal fellowship curricula to brief laparoscopic or open approaches, from lateral-to-medial mobilization through specimen extraction and anastomosis planning. It also fits operative notes, patient education for elective colectomy after complicated diverticulitis, and publisher atlases that need a clean reference model of colon anatomy without distracting surrounding viscera. Anatomical accuracy verified by SciePro's Medical Advisory Board.