"Straight Thumb Sign"
"Straight Thumb Sign"
Median nerve lesions in the forearm cause weakness of flexor pollicis longus, which normally flexes the distal phalanx of the thumb. Hence the thumb remains straight when the patient attempts to grasp something or make a fist. The "pinch sign" may also be present.
References
Cherington M. Anterior interosseous nerve syndrome straight thumb sign. Neurology 1977; 27: 800-801
Cross References
