<prompt> Air on either side of the bowel wall on a radiograph is called:Air under diaphragm signCupola signDoges cap signRigler sign  <response>: The Rigler sign, also known as the double-wall sign, is a sign of pneumoperitoneum seen on an abdominal radiograph when gas is outlining both sides of the bowel wall, i.e. gas within the bowels lumen and gas within the peritoneal cavity. It is seen with large amounts of pneumoperitoneum 1000 mL. 