The radial nerve is the major nerve serving the extensor compartment of the arm. This article describes the anatomic features, clinical features based on lesion location, electrodiagnostic assessment, prognosis, and treatment of radial neuropathies. Numerous traumatic causes have been reported to result in radial neuropathies, including compression or stretch injury, surgical insult, or trauma. Entrapment is a rare cause of radial neuropathy. Electrodiagnostic testing has been used to distinguish radial neuropathy from other disorders presenting with wrist or finger drops. In addition, its use may aid in determining the prognosis for recovery of functional movement.