An interactive Flash diagram of the location and function of the Accessory Nerve CNXI. This nerve has two roots—the cranial root and the spinal root—and the first controls the muscles of the soft palate and pharynx (joining with the Vagus Nerve), while the second supplies the Sternocleidomastoid (SCM) and trapezius muscles of the neck, to help you turn/tilt your head and shrug your shoulders. Highlight, paint, or label individual pieces.