Which sign indicates appendicitis when passive extension of the thigh causes abdominal pain?

• A. Rovsing's sign
• B. Rebound tenderness
• C. Psoas sign
• D. Rectal exam

Answer: (C)

The sign being tested is irritation of the iliopsoas muscle by an inflamed appendix. When the thigh is passively extended, the iliopsoas is stretched; if the appendix lies near or irritates this muscle (often retrocecal), the stretch provokes pain in the right lower quadrant, pointing toward appendicitis. This distinguishes it from other signs: Rovsing’s sign involves pain in the RLQ with palpation of the LLQ, rebound tenderness is general peritoneal irritation, and a rectal exam is not a specific indicator of appendicitis.