Telltale triangle sign

The telltale triangle sign, also known as the triangle sign or telltale triangle, is a radiographic sign seen on plain abdominal radiographs in a supine, cross table lateral or decubitus view that signifies presence of pneumoperitoneum, of any cause .

It describes the appearance of a radiolucent triangle of gas formed between three loops of bowel or between two loops of bowel and the abdominal wall .