Claw hand is associated with injury to which nerve?

• A. Median nerve
• B. Radial nerve
• C. Axillary nerve
• D. Ulnar nerve

Answer: (D)

Claw hand shows loss of intrinsic hand muscle control, specifically those muscles that polarize finger movements and balance the action of the finger flexors. The ulNAR nerve supplies the interossei and the medial two lumbricals, which normally flex the metacarpophalangeal joints while extending the PIP and DIP joints. When the ulnar nerve is injured, these intrinsic muscles can no longer oppose the extrinsic finger flexors and extensors. The extensor digitorum dominates at the MCP joints, causing hyperextension there, while the PIP and DIP joints remain flexed, producing the characteristic clawing, especially in the ring and little fingers. This pattern can occur with a lesion at the wrist or higher up in the arm.

Understanding contrast helps: injury to the median nerve affects different intrinsic muscles and often presents as a hand with benediction when attempting to make a fist, while radial nerve injury leads to wrist drop, and axillary nerve injury causes loss of shoulder abduction. None of these produce the same clawing pattern seen with ulnar nerve palsy. Sensory involvement in the ulnar distribution may accompany the motor pattern as well.