Sigmoid mesocolon

The mesocolon sigmoid is the fold of peritoneum that attaches the sigmoid part of the colon to the dorsal body wall.

It contains blood vessels, lymphatics, and nerves that supply the sigmoid colon. While this structure is more clearly defined in humans, in domestic animals, the sigmoid colon may be less prominent or absent depending on the species, especially in carnivores like dogs and cats.

In large animals such as ruminants and pigs, the equivalent mesenteric regions are more developed and complex due to the greater length and coiling of the large intestine. The sigmoid flexure, when present (especially in pigs and ruminants), is supported by a mesentery that can be referred to as the sigmoid mesocolon.