<unk> , 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<unk>  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.
A false double wall sign can result from two loops of bowel being in contact with one another.
Rigler's sign
Pemberton's sign
Adson's sign
Goodell's sign
Hegar's sign
Cullen's sign
Kussmaul's sign
Rovsing's sign