Left shoulder nerve plexus. Artwork of the nerves (yellow), arteries (red), muscles (red-brown) and bones (light brown) of the left shoulder, seen from the front. This nerve plexus lies between the clavicle bone (bottom) and the carotid artery (red). The nerve running from left is the phrenic nerve. The muscles are the infrahyoid (upper left), the sternocleidomastoid (top right), and the trapezius (centre right). The muscles of the nerve plexus are (left to right): the anterior scalene, middle scalene, and posterior scalene. For the right shoulder, see C016/6815.