On a supine abdominal X-ray, free intraperitoneal gas outlines BOTH sides of the bowel wall, making the wall visible as a thin white line. This sign is called:
- A Rigler's sign (double wall sign) ✓
- B Cupola sign
- C Football sign
- D Telltale triangle sign
Correct answer: A. Rigler's sign (double wall sign)
Explanation
Rigler's sign (double-wall sign) occurs when free intraperitoneal air accumulates on both sides of the bowel wall, allowing both the inner (mucosal) and outer (serosal) surfaces to be visible, making the bowel wall appear as a thin opaque line — unlike normal where only the mucosal surface is seen against intraluminal gas. The cupola sign is subdiaphragmatic free air collecting under the central tendon of the diaphragm. The football sign is a large oval lucency in neonates from massive pneumoperitoneum. The telltale triangle is triangular lucency between bowel loops.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.