Sigmoid colon

Last revised by Dr Daniel J Bell on 12 Oct 2021

The sigmoid colon is the continuation of the descending colon.

After the distal descending colon has curved medially it enters the pelvis, where it gains a mesentery and is then called the sigmoid colon. It measures approximately 15 cm in length. 

It has a "S" (Greek letter sigma (σ)) shape and has a variable length and course - its apex may be as high as the umbilicus. It lies on its own mesentery - the inverted V-shaped sigmoid mesocolon.

The sigmoid colon continues as the rectum when it loses its mesentery, at approximately S3 level. 

Lymphatics travel with vessels to the inferior mesenteric group.

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Cases and figures

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