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Cranial Nerves

The cranial nerves are composed of twelve pairs of nerves that emanate from the nervous tissue of the brain. In order to reach their targets they must ultimately exit/enter the cranium through openings in the skull. Hence, their name is derived from their association with the cranium. The following are the list of cranial nerves, their functions, and tumor examples:

# Name Function Tumor Example
I olfactory The olfactory nerve carries impulses for the sense of smell. Esthesioneuronblastoma
II optic The optic nerve carries impulses for the sense of sight. Optic nerve glioma
III occulomotor The occulomotor nerve is responsible for motor enervation of upper eyelid muscle, extraocular muscle and pupillary muscle. Schwannoma
IV trochlear The trochlear nerve controls an extraocular muscle. Schwannoma
V trigeminal The trigeminal nerve is responsible for sensory enervation of the face and motor enervation to muscles of mastication (chewing). Malignant peripheral nerve sheath tumor (MPNST)
VI abducent The abducent nerve enervates a muscle, which moves the eyeball. Schwannoma
VII facial The facial nerve enervates the muscles of the face (facial expression). Schwannoma (rare)
VIII vestibulocochlear The vestibulocochlear nerve is responsible for the sense of hearing and balance (body position sense). Vestibular Schwannoma
IX glossopharyngeal The glossopharyngeal nerve enervates muscles involved in swallowing and taste. Lesions of the ninth nerve result in difficulty swallowing and disturbance of taste. Glomus tumor
X vagus The vagus nerve enervates the gut (gastrointestinal tract), heart and larynx. MPNST, paraganglioma
XI accessory The accessory nerve enervates the sternocleidomastoid muscles and the trapezius muscles. Schwannoma
XII hypoglossal The hypoglossal nerve enervates the muscles of the tongue. Schwannoma

For more information about anatomy of brain and CNS, go to the Nervous System section of the Anatomy & Physiology module on this Web site.