A 60 year-old male presented with acute severe abdominal pain. CT shows twisting of small bowel and mesentery around superior mesenteric artery (whirl sign).

Malrotation is incomplete rotation of the bowel during embryologic development. As a result, the mesenteric root, which extends from the duodenojejunal junction (ligament of Treitz) to ilioceacal junction is shortened. The resultant short mesenteric root predisposes to volvulus of midgut (the portion of bowel supplied by the superior mesenteric artery). Midgut volvulus is the subsequent twisting of bowel around the superior mesenteric artery leading to bowel obstruction and ischemia. Urgent surgical repair is often required to prevent ischemia or to resect infarcted bowel loops.

Reference: WE Berdon: Midgut Volvulus with Whirlpool sign. AJR;1999:172:1689-1690.

Credit: Dr Ahmed Haroun