twisting of a portion of the digestive tract on its mesentery (the fold of membrane that attaches the intestine to the posterior abdominal wall), resulting in intestinal obstruction, severe pain, distension of the involved segment, and interference with circulation to the affected area. Volvulus may be congenital or acquired; the areas most frequently affected are the sigmoid colon, the ileocecal region, and the stomach. Treatment of severe volvulus is usually surgical; removal of part of the organ may be necessary to prevent recurrence.