The sigmoid colon commences at the termination of the descending colon, opposite the lateral border of the psoas muscle in the left iliac fossa. It terminates opposite the middle piece of the sacrum, at the lower limit of the pelvic mesocolon. It is the narrowest portion of the colon. Although the peritoneum usually begins to surround the gut at this level, it frequently occurs that the meso is exceedingly short until the lower portion of the sigmoid colon is approached. Here it lies in contact with the bladder, the uterus and its appendages, and those coils of the small intestine which lie in the pelvis. The rectosigmoid curve is the abrupt bend formed at the junction of the sigmoid colon and the rectum. It is caused by gravitation of the movable sigmoid colon to the floor of the pelvis and the immobility of the rectum.

Colon sigmoideum

Côlon sigmoïde