What does a positive Murphy sign indicate in a clinical examination?

A positive Murphy sign is indicative of a dislocated lunate. This clinical sign is tested by having the patient make a fist and then examining the position of the third metacarpophalangeal joint. If the patient's third metacarpal is level with or below the second and fourth, it suggests that the lunate bone has shifted out of its normal position, typically due to a dislocation.

Other conditions listed, such as fracture of the radius, tendon injury, and carpal tunnel syndrome, do not specifically elicit the positive Murphy sign. A fracture of the radius might present with pain, swelling, or deformity in the wrist area but does not result in the specific alignment change associated with the Murphy sign. Similarly, tendon injuries will often manifest through range of motion limitations or pain but would not produce the characteristic sign associated with lunate dislocation. Carpal tunnel syndrome is associated with symptoms of numbness and tingling in the hand due to median nerve compression, rather than changes in the anatomical relationship that the Murphy sign reveals. Thus, the indication of dislocated lunate is what makes this sign clinically significant.