Anatomical Basis of Claw Hand

Nerve Involvement: Ulnar and Median Nerve Pathology

Claw hand is a deformity resulting from damage to the ulnar and median nerves, affecting intrinsic hand muscles.

Anatomical Considerations

• Ulnar Nerve: Controls most intrinsic hand muscles, including lumbricals of digits 4 and 5.
• Median Nerve: Responsible for lumbricals of digits 2 and 3 and thumb opposition.

Pathophysiology

When the ulnar nerve is damaged, the lumbricals of digits 4 and 5 fail to flex at the metacarpophalangeal joints while the extensor muscles remain active, creating a claw-like appearance.

Clinical Presentation

• Hyperextension at the metacarpophalangeal joints.
• Flexion at the interphalangeal joints of digits 4 and 5.
• Loss of fine motor movements in the hand.

Causes and Risk Factors

Common causes include:

• Trauma to the ulnar nerve.
• Compression syndromes (e.g., cubital tunnel syndrome).
• Diabetic neuropathy.

Diagnosis

Diagnosis involves neurological examination, electromyography (EMG), and imaging studies to assess nerve integrity.

Treatment and Management

• Physical therapy to improve strength and mobility.
• Surgical intervention in severe cases.
• Orthotic devices for functional assistance.

Early intervention can significantly improve outcomes and hand function.