'''Rigler's sign''', also known as the '''double wall sign''', is seen on an X-ray of the Abdomen when air is present on both sides of the Intestine; a Rigler's sign is present when air is present on the inside (lumenal side) and the outside (peritoneal side). Air in the Peritoneum is considered abnormal, unless the patient had a recent Abdominal_surgery. ==See also== *Football_sign - another sign of Pneumoperitoneum. ==References== *Harkin DW, Blake G. Small bowel obstruction in a young adult. Postgrad Med J. 1999 Mar;75(881):173-5. PMID 10448501. Free Full Text. ==External links== *A film of Rigler's sign and the Football_sign - learningradiology.com Category:Eponymous_medical_signs Category:Gastroenterology Category:Radiology