Accessory nerve (XI) lesions - Disorders of cranial nerves

Accessory nerve (XI) lesions

Anatomy

Spinal accessory branch arises from upper cervical cord segments and passes through the foramen magnum to join the cranial accessory branch. They leave the skull separately through the jugular foramen.

Function

Cranial nerves join the pharyngeal plexus and supply the muscles of the palate, pharynx and larynx. The spinal part supplies trapezius and sternocleidomastoid.

Specific causes

Polio, syringomyelia, tumours near the jugular foramen.

Clinical features

Weakness of lifting ipsilateral shoulder and turning head against resistance towards the contralateral side.