In hand ROM, inability to extend the wrist during examination suggests injury to which nerve?

In hand ROM, inability to extend the wrist during examination suggests injury to which nerve?

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

Answer: (C)

Wrist extension is carried out by the extensor muscles of the posterior forearm, all of which are innervated by the radial nerve. When the radial nerve is damaged, these extensors—especially the extensor carpi radialis longus and brevis, and the extensor carpi ulnaris—cannot contract to lift or extend the dorsum of the hand, producing a wrist drop during ROM. The median and ulnar nerves mainly control finger flexors and intrinsic hand muscles, and the axillary nerve supplies the deltoid and teres minor, not wrist extension. Thus, inability to extend the wrist points to radial nerve injury.

Wrist extension is carried out by the extensor muscles of the posterior forearm, all of which are innervated by the radial nerve. When the radial nerve is damaged, these extensors—especially the extensor carpi radialis longus and brevis, and the extensor carpi ulnaris—cannot contract to lift or extend the dorsum of the hand, producing a wrist drop during ROM. The median and ulnar nerves mainly control finger flexors and intrinsic hand muscles, and the axillary nerve supplies the deltoid and teres minor, not wrist extension. Thus, inability to extend the wrist points to radial nerve injury.