Which sign is used to diagnose lunate dislocation?

• A. Murphy's sign
• B. Finkelstein's test
• C. Phalen's test
• D. Watson test

Answer: (A)

Murphy's sign is used to diagnose lunate dislocation. When a patient makes a tight fist, the normal appearance is that the knuckles peak at similar heights. If the lunate is dislocated, the capitate shifts proximally and the third metacarpal head loses its normal prominence, so the third knuckle appears flattened or level with the others. This alteration—the loss of the expected third-knuckle elevation when the fist is made—is a positive Murphy’s sign and points to lunate dislocation. The other signs test different conditions: Finkelstein’s for de Quervain’s tenosynovitis, Phalen’s for carpal tunnel syndrome, and the Watson test for scapholunate instability, not lunate dislocation.