The shoulder’s motor nerves emerge from the front branches of the lower four cervical nerves and the first thoracic nerve, which produce the brachial plexuses. These networks of nerve fibers are located deep within the shoulders between the neck and the axillae (armpits). The major branches emerging from the brachial plexuses include musculocutaneous nerves, which supply muscles of the arms on the Continue Scrolling To Read More Below...