Wrist Drop: Radial Nerve Injury Causes and Presentation

Wrist drop (inability to extend wrist/fingers) results from radial nerve damage.

Anatomy

Radial nerve (C5–T1) runs posterior arm → forearm; innervates triceps (elbow extension) and wrist/finger extensors.

Common Injury Mechanisms

• Humeral shaft fracture (mid-spiral groove)
• Elbow dislocation/fracture
• Compression (Saturday night palsy, crutch palsy)
• Laceration or stretch injury

Presentation

• Wrist/finger extension paralysis → hand hangs flaccid
• Weak elbow extension (if high injury)
• Sensory loss: dorsal hand/web space

Urgent evaluation needed; recovery depends on injury severity (neuropraxia vs. axonotmesis).