Froment sign

Froment's sign

Froment's sign is a clinical sign used in the field of neurology to evaluate for ulnar nerve palsy, specifically, the functionality of the adductor pollicis muscle. It is named after Jules Froment, a French neurologist who first described the sign.

Overview

Froment's sign is elicited by asking the patient to hold a piece of paper between their thumb and the lateral aspect of their index finger (pinch grip). The examiner then attempts to pull the paper away. A positive Froment's sign is indicated by the patient's inability to maintain grip on the paper, leading to compensation through flexion of the thumb's interphalangeal joint. This compensation is due to weakness of the adductor pollicis muscle, which is innervated by the ulnar nerve, and the recruitment of the flexor pollicis longus muscle, which is innervated by the median nerve.

Pathophysiology

The ulnar nerve is responsible for the innervation of several muscles in the hand, including the adductor pollicis. Damage or compression of the ulnar nerve, therefore, can lead to weakness or paralysis of these muscles, manifesting clinically as Froment's sign among other symptoms. Ulnar nerve palsy can result from various causes, including trauma, elbow or wrist fractures, and chronic compression from repetitive movements.

Clinical Significance

Froment's sign is a valuable diagnostic tool in assessing ulnar nerve function. A positive sign suggests ulnar nerve dysfunction, which can guide further diagnostic evaluation and management. It is particularly useful in distinguishing between ulnar nerve lesions and other conditions that may cause hand weakness, such as carpal tunnel syndrome or cervical radiculopathy.

Management

Management of a positive Froment's sign involves addressing the underlying cause of ulnar nerve dysfunction. This may include conservative measures such as rest, splinting, and physical therapy, or more invasive approaches like surgery to decompress the nerve or repair nerve damage.

See Also

• Hand of Benediction
• Tinel's Sign
• Phalen's Maneuver
• Carpal Tunnel Syndrome
• Ulnar Nerve Entrapment