Froment has two eponymous signs:
- Activated rigidity or synkinesis (q.v.).
- In an ulnar nerve lesion, flexion of the distal phalanx of the thumb (flexor pollicis longus, innervated by the median nerve) is seen when attempting to squeeze a sheet of paper between the thumb and the index finger, as a compensation for the weakness of thumb adduction (adductor pollicis, innervated by the ulnar nerve), also known as Froment’s prehensile thumb sign or the signe du journal. The term is also sometimes used for weakness of little finger adduction, evident when trying to grip a piece of paper between the ring and little finger.