Radial Nerve Palsy: Wrist Drop Causes, Recovery & Physiotherapy Treatment

Radial Nerve Palsy: Physiotherapy Rehabilitation for Wrist Drop

The radial nerve is the largest branch of the brachial plexus (C5-C8, T1) and innervates all the extensor muscles of the wrist and fingers, as well as the brachioradialis and triceps. Radial nerve palsy at the spiral groove level (the most common site) produces the classic wrist drop deformity — inability to extend the wrist, fingers, or thumb.

Clinical Assessment

Motor deficits: Wrist drop (inability to extend wrist). Loss of finger and thumb extension. Weakness of brachioradialis (forearm semi-flexion).

Sensory deficits: Loss of sensation over the posterior forearm and dorsum of the hand (the anatomical snuffbox region and proximal dorsum of digits 1–3).

Preserved function (spiral groove lesion): Triceps (branches higher up are spared). Sensation of posterior arm.

Physiotherapy Management Phases

Phase 1: Splinting & Prevention of Contracture

Wrist drop causes a mechanical disadvantage for finger flexion (the flexor tendons cannot generate grip force without the wrist being extended). A cock-up wrist splint (wrist in 20–30° extension) is applied immediately:

• Restores functional grip ability
• Prevents wrist and finger flexor contracture from maintained wrist flexion
• Worn throughout the day; removed for exercises

Phase 2: Maintaining Passive Range of Motion

Daily therapist-performed passive extension of wrist and all finger IP and MCP joints. Prevents flexion contractures that would impede recovery even after nerve regeneration.

Phase 3: Electrotherapy for Denervated Muscles

Faradic stimulation (alternating current): Applied over the wrist extensors, finger extensors, and abductor pollicis longus to maintain muscle bulk and reduce atrophy during the denervation period. 15–20 minutes, 5 days/week.

NMES (Neuromuscular Electrical Stimulation): Once voluntary motor unit activity begins returning (often 6–8 weeks post-injury), NMES combined with active intention amplifies early motor re-learning.

Phase 4: Active Exercise Restoration

As radial nerve function returns (follow with monthly MMT grading):

• Wrist extension against gravity: Progress from gravity-eliminated to against gravity to resisted
• Finger extension: Begin with support under the wrist, progress to full wrist extended position
• Thumb abduction and extension: Key for pinch function

Functional Retraining

• Writing simulation, keyboard use
• Grasp-and-release task training
• Return to occupation-specific tasks