Froment's sign

Froment's sign tests for palsy of the ulnar nerve, specifically, the action of adductor pollicis. To perform the test, a patient is asked to hold an object, usually a piece of paper, between the thumb and a flat palm. The object is then is pulled away.

A normal individual will be able to maintain a hold the object without difficulty. However, with ulnar nerve palsy, the patient will experience difficultly maintaining a hold and will compensate by flexing the flexor pollicis longus of the thumb.

Clinically, this compensation manifests as flexion of the DIP joint of the thumb (rather than extension, as would occur with correct use of the adductor pollicis). Note that the flexor pollicis longus is normally innervated by the anterior interosseous branch of the median nerve.

Another way to perform this test is to have the patient hold the piece of paper between the tip of the thumb and the tip of the index finger. Then, pull the paper out from between their fingers asking patient not to let go of it. If the patient has to resort to pad-to-pad pinch, the patient is positive for Froment's sign.

Froment-Zeichen