innerbody
Diagram

Shoulder (Motor)

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...

Continued From Above... front side and skin of the forearms; radial nerves, which supply muscles on the back of the arms and the skin of the forearms and hands; and axillary nerves, which supply muscles and skin of the upper, lateral, and posterior regions of the arms.