Validation of a diagnostic sign in carpal tunnel syndrome.

Of three signs in carpal tunnel syndrome, Phalen's, Tinel's and the Flick sign, the last of these was the most valid and reliable. The presence of a positive Flick sign predicted electrodiagnostic abnormality in 93% of cases and had a false positive rate of under 5% among other neural lesions in the arm. The key question consists of an enquiry as to what the patient does with the affected hand at times when symptoms are at their worst; a flicking movement of the wrist and fingers demonstrated by the patient constitutes a positive response.