radialisnerven

The radialisnerven, or nervus radialis, is a major peripheral nerve of the upper limb. It arises from the posterior cord of the brachial plexus (C5–T1) and supplies the posterior compartments of the arm and forearm, as well as providing cutaneous innervation to the dorsolateral aspect of the hand.

Course and branches: The nerve travels down the arm in the radial groove with the profunda brachii artery and gives motor branches to the triceps, anconeus, and the extensors of the forearm. Near the lateral epicondyle it divides into a superficial branch (sensory) and a deep branch (motor). The deep branch passes between the heads of the supinator, through the arcade of Frohse, and becomes the posterior interosseous nerve, which innervates most of the forearm’s extensor muscles.

Innervation specifics: The superficial branch provides sensation to the dorsolateral hand and the dorsal surfaces of the lateral three and a half digits. The deep branch, after transforming into the posterior interosseous nerve, supplies the majority of the finger and thumb extensor muscles.

Clinical significance: Trauma or compression of the radial nerve can cause radial nerve palsy, with weakness of elbow, wrist, and finger extension and sensory loss on the dorsolateral hand, depending on the injury site. Classic presentations include wrist drop after humeral shaft fracture or compression syndromes such as radial tunnel syndrome and posterior interosseous nerve syndrome, where motor loss may occur with variable sensory deficit. Diagnosis relies on clinical examination and electrodiagnostic studies. Treatment ranges from conservative management with splinting and rehabilitation to surgical decompression or nerve repair, guided by the lesion location and severity.