The mesodiverticular band is an embryologic remnant of the vitelline circulation which carries the arterial supply to the Meckel's diverticulum. In the event of an error of involution, a patent or nonpatent arterial band persists and extends from the mesentery to the apex of the antimesenteric diverticulum. This creates a snare-like opening through which bowel loops may herinate and become obstruced. Clinical and radiological findings of acute, low, small-bowel obstruction are produced by this band.