"Pinch Sign"

"Pinch Sign"

The "pinch sign" is an inability to make a small circle ("form the letter O") by approximating the distal phalanges of the thumb and index finger, due to weakness of flexor digitorum profundus in the index finger and flexor pollicis longus in the thumb as a consequence of median nerve lesions in the forearm, e.g., anterior interosseous syndrome, pronator teres syndrome. This results in a pinching posture of thumb and index finger. The "straight thumb sign" may also be present (q.v.).

Cross References

Froment’s sign; "Straight thumb sign"