Froment sign

Clinical sign of ulnar nerve dysfunction

Froment's sign is a clinical test used to assess the function of the ulnar nerve, particularly its innervation to the adductor pollicis muscle. This sign is named after the French neurologist Jules Froment.

Clinical Significance

Froment's sign is primarily used to detect ulnar nerve palsy, which can result from various conditions such as cubital tunnel syndrome, Guyon's canal syndrome, or trauma to the elbow or wrist. The ulnar nerve is responsible for innervating several muscles in the hand, including the adductor pollicis, which is crucial for thumb adduction.

Test Procedure

To perform the test, the patient is asked to hold a piece of paper between the thumb and index finger, using a lateral pinch grip. The examiner then attempts to pull the paper away. In a normal response, the patient will maintain the grip using the adductor pollicis muscle, which is innervated by the ulnar nerve.

Froment's sign test

Positive Froment's Sign

A positive Froment's sign is indicated by the patient's inability to maintain the grip with the thumb flat against the index finger. Instead, the patient compensates by flexing the thumb's interphalangeal joint, using the flexor pollicis longus muscle, which is innervated by the median nerve. This compensatory action is due to weakness or paralysis of the adductor pollicis muscle.

Associated Conditions

Froment's sign is often associated with conditions that affect the ulnar nerve, including:

• Cubital tunnel syndrome
• Guyon's canal syndrome
• Ulnar nerve entrapment
• Trauma to the elbow or wrist

Differential Diagnosis

While Froment's sign is indicative of ulnar nerve dysfunction, it is important to differentiate it from other conditions that may affect hand function, such as:

• Carpal tunnel syndrome
• Radial nerve palsy
• Cervical radiculopathy

Management

Management of a positive Froment's sign involves addressing the underlying cause of ulnar nerve dysfunction. Treatment options may include:

• Physical therapy
• Occupational therapy
• Surgical intervention for nerve decompression
• Splinting to prevent further nerve damage

Related Pages

• Ulnar nerve
• Cubital tunnel syndrome
• Guyon's canal syndrome
• Nerve conduction study