The Froment sign is defined as compensatory flexion of the distal phalanx of the thumb by the flexor pollicis longus muscle, which occurs with paralysis of the adductor pollicis muscle.
Historical background
The Froment sign is named after the French neurologist Jules Froment (1878–1946), who observed the sign in patients with injuries to the ulnar nerve[^1].
Assessment
The Froment sign can be assessed by asking the patient to hold a sheet of paper firmly.
Interpretation
A positive Froment sign may occur with a distal lesion of the Ulnar nerve, as in patients with cubital tunnel syndrome. In the presence of concomitant Median nerve palsy, the Froment sign may be negative despite a distal ulnar nerve lesion.