Spinal pa of accesory nerve supplies: March 2009

Ans. C: SternocleidomastoidThe spinal root arises from nerve cells in the anterior gray column (horn) of the upper five segments of the cervical pa of the spinal cord. The nerve ascends alongside the spinal cord and enters the skull through the foramen magnum. It then turns laterally to join the cranial root.The two roots unite and leave the skull through the jugular foramen.The roots then separate:The cranial root joins the vagus nerves and is distributed in its branches to the muscles of the soft palate and pharynx ( the pharyngeal plexus) and to the muscles of the larynx (except the cricothyroid muscle).The spinal root runs downward and laterally and enters the deep surface of the sternocleidomastoid muscle, which it supplies, and then crosses the posterior triangle of the neck to supply the trapezius muscle.The accessory nerve thus brings about movements of the soft palate, pharynx, and larynx and controls the movements of the sternocleidomastoid and trapezius muscles.