The caecum and vermiform appendix are supplied by the ileo-colic; the ascending colon by the right colic; and the transverse colon by the middle colic of the superior mesenteric ; while the descending colon is supplied by the left colic, and the iliac and pelvic colon by the sigmoid arteries of the inferior mesenteric. The rectum is supplied by the three haemorrhoidal arteries. The veins present similar arrangements.

The middle colic artery supplying the transverse colon runs in the transverse mesocolon ; and in performing a gastroenterostomy, in which the mesocolon is perforated, care is necessary to avoid injury to the artery, which would probably be followed by gangrene of the transverse colon.

The nerve-supply is derived from the superior mesenteric from the solar plexus, and from the inferior mesenteric from the aortic plexus.

The lymphatics draining the bowel from caecum to upper portion of descending colon pass to the mesocolic glands, which lie behind the ascending and descending colon, between the layers of the transverse mesocolon. Those draining the lower half of the descending colon, and iliac and pelvic colons, join the left lymphatic trunk of the lumbar glands.