Arc of Riolan: A Vascular Boon in Colonic Ischemia - A Rare Case Report

Large intestine is supplied partly by the branches of superior mesenteric artery (SMA) and partly by inferior mesenteric artery (IMA). These branches further at the peripheral aspect form anastomotic channel called as marginal artery of Drummond which gives branches to all parts of large intestine. Arc of Riolan is a collateral channel that connects the proximal superior mesenteric artery (SMA) or its middle colic branch and the proximal inferior mesenteric artery (IMA) or its left colic branch. It is found only in 10% of the individuals. If present it become prominent whenever there is SMA or IMA obstruction or compression due to arterial plaques or any other surrounding growing visceral tumor mass. With increasing laproscopic abdominal surgical procedures like colonic interposition or divisional surgeries, knowledge of vascular anatomy of colon is prerequisite to prevent unwanted complications.