A patient reports numbness and tingling in the thumb, index, and middle fingers. The nurse asks the patient to press the backs of both hands together while flexing the wrists at 90 degrees for 60 seconds. If the maneuver triggers symptoms, it is considered a positive:

Phalen's test assesses for median nerve compression within the carpal tunnel. Sustained hyperflexion increases interstitial pressure, eliciting paresthesia or hypoesthesia in the lateral 3.5 digits. This clinical diagnostic tool identifies carpal tunnel syndrome resulting from tenosynovitis or anatomical narrowing. A. Tinel's sign: Percussion of the volar carpal ligament elicits distal tingling or electric shock sensations in the median nerve distribution. This maneuver identifies nerve irritability rather than compression from sustained flexion. It serves as a secondary clinical indicator for focal entrapment. B. Allen test: This vascular assessment evaluates the patency of the radial and ulnar arteries supplying the palmar arch. Compression and release of these vessels demonstrate collateral circulation through skin reperfusion. It is not used for neurological or sensorimotor nerve entrapment. C. Finkelstein test: Passive ulnar deviation of the wrist with the thumb flexed into the palm identifies de Quervain tenosynovitis. This maneuver stretches the abductor pollicis longus and extensor pollicis brevis tendons. It focuses on stenosing tenosynovitis rather than carpal nerve compression. D. Phalen's test: Maintaining 90 degree wrist flexion for 60 seconds mechanically constricts the carpal tunnel. The resulting ischemia triggers tingling in the thumb, index, and middle fingers. This positive finding specifically correlates with the entrapment of the median nerve described.