The whirlpool sign, also known as the whirl sign, is seen in a number of settings when a structure twists upon its pedicle. It is most commonly described in the abdomen where bowel rotates around its mesentery, with mesenteric vessels creating the whirls. It can also be seen in omental and ovarian torsion.

Omental torsion is a rare cause of acute abdominal pain that occurs in the third to fifth decade of life with slight male predominance. It can be primary or secondary.

• primary omental torsion: No identifiable cause but may be related to local omental anatomical variations that allow a movable segment of omentum to twist around the proximal fixed point.
• secondary omental torsion: More frequent than primary omental torsion. It occurs secondary to hernial sacs, surgical scars or wounds, tumors, and cysts. Inguinal hernias are the most common cause of secondary omental torsion.

Special thanks to Dr. Naina Hakobyan, "AMC" Hospital, Armenia Department of Radiology, for contributing this case.