Which condition is tested by direct percussion at the median nerve of the wrist?

The direct percussion at the median nerve of the wrist is used to assess for the presence of Tinel's sign. This maneuver involves tapping over the median nerve at the wrist, which can reproduce symptoms such as tingling or numbness in the fingers innervated by this nerve, particularly the thumb, index, and middle fingers. The presence of these symptoms indicates irritation or compression of the median nerve, commonly associated with conditions like carpal tunnel syndrome.

In contrast, the bulge sign is used to assess for fluid in the knee joint and is unrelated to nerve assessment. Phalen's test evaluates for median nerve compression as well, but it involves flexing the wrists in a certain position to see if symptoms arise, rather than direct percussion. Carpal compression involves applying pressure over the carpal tunnel to elicit symptoms, but it is not the same as directly tapping the nerve. Thus, the use of direct percussion specifically aligns with identifying Tinel's sign.