Radial nerve
Latin: Nervus radialis sinistra
Paired structure: one on the left and one on the right side of the body.
View the radial nerve in 3DRoots
Posterior cord (C5–T1).
Course
The largest branch of the plexus: descends behind the axillary artery, spirals the humeral shaft in the radial groove with the profunda brachii between the medial and lateral heads of triceps, pierces the lateral intermuscular septum, and enters the forearm anterior to the lateral epicondyle, dividing into a superficial sensory branch and the deep posterior interosseous nerve.
Motor supply
All extensors of the elbow, wrist and fingers; triceps, brachioradialis, anconeus and the forearm's extensor compartment.
Sensory supply
Posterior arm and forearm, the dorsum of the radial hand (its autonomous zone: the first dorsal web space).
Clinical relevance
Mid-shaft humeral fractures in the radial groove cause wrist drop — the examination classic. Saturday-night palsy compresses it against the humerus in drunk sleep; the posterior interosseous branch's arcade of Frohse spares the wrist extensors when compressed, dropping only the fingers.
Educational anatomy reference, not medical advice. About this content.