On supine simple radiography, falciform ligament (arrow) is well demonstrated in RUQ area, suggesting large amount of free air in the nondependent abdominal cavity. This is called the falciform ligament sign. Bowel wall is also well delineated as a smooth line because of luminal and extraluminal air. This is called the Rigler sign or double-wall sign. On the cross-lateral table view, free gas is evident (asterisks). Laparotomy showed ileal perforation. dewagacor
