Froment's sign

Froment's sign is a special test of the wrist. It tests for palsy of the ulnar nerve, specifically, the action of adductor pollicis. ^[1] Froment sign can also refer to cogwheel effect seen in essential tremor.

Process of examination

To perform the test, a patient is asked to hold an object, usually a flat object such as a piece of paper, between their thumb and index finger (pinch grip). The examiner then attempts to pull the object out of the subject's hands.^[2]

• A normal individual will be able to maintain a hold on the object without difficulty.
• However, with ulnar nerve palsy, the patient will experience difficulty maintaining a hold and will compensate by flexing the FPL (flexor pollicis longus) of the thumb to maintain grip pressure causing a pinching effect.^[3]
• Clinically, this compensation manifests as flexion of the IP joint of the thumb (rather than extension, as would occur with correct use of the adductor pollicis).
• The compensation of the affected hand results in a weak pinch grip with the tips of the thumb and index finger, therefore, with the thumb in obvious flexion.^[4]
• Note that the FPL is normally innervated by the anterior interosseous branch of the median nerve.
• Please be aware, anterior interosseous branch comes off more proximally than the wrist, in evaluating lacerations near the wrist.
• Simultaneous hyperextension of the thumb MCP joint is indicative of ulnar nerve compromise. This is also known as Jeanne's Sign.^[5]

Eponym

It is named for Jules Froment.^[6][7]

References