The middle mesenteric artery: an unusual source for colonic hemorrhage.

To the authors' knowledge, colonic hemorrhage from anomalous ventral aortic mesenteric arteries has not been described previously. They report a case in which a middle mesenteric artery with unusual vascular distribution supplied a splenic flexure hemorrhage in a 62-year-old man. Although this is a rare anomaly, a thorough understanding of the middle mesenteric artery may have important diagnostic and therapeutic implications.