Sigmoid mesocolon

The sigmoid mesocolon is the fold of peritoneum which retains the sigmoid colon in connection with the pelvic wall.

Its line of attachment forms a V-shaped curve, the apex of the curve being placed about the point of division of the left common iliac artery.

The curve begins on the medial side of the left Psoas major, and runs upward and backward to the apex, from which it bends sharply downward, and ends in the median plane at the level of the third sacral vertebra.

The sigmoid and superior hemorrhoidal vessels run between the two layers of this fold.