Sigmoid colon

Last revised by Craig Hacking on 13 Oct 2022

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

  • Figure 1
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