Radial nerve lesions - Disorders of Peripheral nerves

Radial nerve lesions

Definition

The radial nerve supplies the extensor muscles of the upper arm and forearm. It is a branch of the brachial plexus.

Aetiology

Injuries to the radial nerve may occur due to elbow fracture/dislocations, in the upper arm due to humerus fractures or prolonged pressure due to hanging an arm over the back of a chair (Saturday night palsy), or in the axilla (crutch palsy). Radial nerve lesions cause weakness in the brachioradialis and triceps muscles.

Clinical features

Wrist drop and sensory loss over the back of the hand at the base of the thumb (the anatomical snuffbox). If there is paralysis of triceps (weakness of elbow extension), this is evidence of a lesion above the upper third of the upper arm, e.g. in the axilla. Low lesions, i.e. at the elbow result in failure to extend the metacarpophalangeal joints.

Management

Compression due to crutch palsy or Saturday night palsy may take up to 3 months to recover. Open wounds should be explored immediately with nerve repair or graft. Other trauma should be given 6 weeks, with surgery if there is no sign of recovery.

Prognosis

Lesions that do not recover can often be overcome by suitable tendon transfers.