The "inverted V" sign of pneumoperitoneum.
On the supine radiograph, an inverted "V" may be seen over the pelvis in a patient with pneumoperitoneum. While in infants this is produced by the umbilical arteries, in adults it appears to be created by the inferior epigastric vessels.
D000009:Abdominal Muscles / Q000098:blood supply; D000328:Adult; D000792:Angiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D011027:Pneumoperitoneum / Q000000981:diagnostic imaging*; D014469:Umbilical Arteries / Q000000981:diagnostic imaging