The radial n. is formed from spinal roots C5, C6, C7, C8, T1. It innervates the following muscles: Triceps, Brachialis, Brachioradialis, Anconeus, Supinator, Extensor carpi radialis longus, Extensor carpi radialis brevis, Extenfor carpi ulnaris, Extensor digitorum communis, Extensor digiti minimi, Abductor pollicis longus, Extensor pollicis brevis, Extensor pollicis longus, and Extensor indicis.