glossary

accessory nerve

Definition accessory nerve

accessory nerve

accessory nerve (spinal accessory nerve) the eleventh *cranial nerve (XI), which arises from two roots, cranial and spinal. Fibres from the cranial root travel with the nerve for only a short distance before branching to join the vagus and then forming the recurrent laryngeal nerve, which supplies the internal laryngeal muscles. Fibres from the spinal root supply the sternomastoid and trapezius muscles, in the neck region (front and back).