Accessory Nerve (XI)

Accessory nerve is the eleventh pair of cranial nerves. It is a motor nerve fibers formed by the cranial (by about 30%.), Originating from the top of the brain stem, and spinal cord (70%), which comes from the top of the bone. These fibers combine to form the accessory nerve (XI), which supplies the trapeze muscles (neck and back) and sternocleidomastoid (neck).