Neuroanatomy, Cranial Nerve 11 (Accessory)

The accessory spinal nerve or XI cranial nerve is essential for neck and shoulder movement, the intrinsic musculature of the larynx, and the sensitive afferences of the trapezius and sternocleidomastoid musculature. It can suffer an injury with daily movements or behaviors that exceed the elastic capacity of the nerve structure, such as excessive stretching or carrying heavyweights. These types of injuries are generally benign. The nerve may be seriously injured if the patient undergoes extensive tumor mass-removal surgery in the neck area, and there is a lack of blood nutrition or partial removal. When necessary, its removal becomes essential to compensate for a peripheral nerve lesion, transfer the cranial nerve where electrical activity is lacking, and efforts to restore limb function.