Spinal nerve root C6 innervates both proximal and distal upper extremity muscles. Distally, C6 fibers form the median nerve. The muscles innervated by C6 are: Serratus anterior, Deltoid, Infraspinatus, Teres minor, Supraspinatus, Teres major, Pectoralis major, Latissimus dorsi, Biceps, Brachialis, Brachioradialis, Supinator, Pronator teres, Flexor carpi radialis, Extensor carpi radialis, Extensor digitorum communis, and Extensor indicis proprius.