The ascending colon is smaller in calibre than the cecum from where it starts.

It is retained in contact with the posterior wall of the abdomen by the peritoneum, which covers its anterior surface and sides, its posterior surface being connected by loose areolar tissue with the iliacus, quadratus lumborum, aponeurotic origin of transversus abdominis, and with the front of the lower and lateral part of the right kidney.

Sometimes the peritoneum completely invests it and forms a distinct but narrow mesocolon.

Parasympathetic innervation to the ascending colon is supplied by the vagus nerve.

This article incorporates text in the public domain from page 1180 of the 20th edition of Gray's Anatomy (1918)