Spinal nerve root C7 innervates proximal, forearm, and hand muscles. Distally, C7 fibers form the median and radial nerves. The muscles innervated by C7 are: Latissimus dorsi, Pectoralis major, Triceps, Pronator teres, Flexor carpi radialis, Extensor carpi radialis, Palmaris longus, Extensor digitorum communis, Extensor indicis proprius, flexor digitorum superficialis, Abductor policis longus, Extensor policis brevis, Extenosr policis longus, Extensor carpi ulnaris, and Flexor carpi ulnaris.