TABLE 14.1 The Cranial Nerves Function

CN X: Vagus nerve

In the head and the neck it provides some sensory innervation from the skin of the head and the pharynx, motor axons to muscles involved in speech and swallowing, and motor axons to certain salivary glands. Outside the head and the neck it innervates most of the thoracic and abdominal viscera as the main nerve of the parasympathetic nervous system. (is the only cranial nerve that "wanders" outside of the head and neck ("vagus" means "wanderer"))

CN XI: Accessory nerve

Its motor axons innervate the muscles that move the head and the neck, (such as the trapezius and sternocleidomastoid muscles) (only cranial nerve that has both a cranial component originating from the brainstem and a spinal component originating from the spinal cord)

CN VII: Facial nerve

innervate many structures and provide for the following: motor to the muscles of facial expression; taste from the anterior two-thirds of the tongue; motor to the glands that produce tears (the lacrimal glands), mucus, and saliva; and sensory from part of the face and mouth.

CN III: Oculomotor nerve

innervates four of the six extrinsic eye muscles that move the eyeball (the muscle that opens the eyelid, the muscle that constricts the pupil, and the muscle that changes the shape of the lens for near vision, an adjustment called accommodation)

CN IV: Trochlear nerve

innervates one of the six extrinsic eye muscles that moves the eyeball (the superior oblique muscle).

CN VI: Abducens nerve

innervates the final extrinsic eye muscle (the lateral rectus muscle).

CN XII: Hypoglossal nerve

innervates the muscles that move the tongue. (Note that the hypoglossal nerve moves the tongue but does not provide any taste sensation to the tongue.)

CN VIII: Vestibulocochlear nerve

innervates the structures of the inner ear and provides for the senses of hearing and equilibrium.

CN V: Trigeminal nerve

innervation to the muscles of mastication (chewing).

CN IX: Glossopharyngeal nerve

muscles of the pharynx (throat) involved in swallowing and sensory fibers from the posterior one-third of the tongue for taste sensation.

CN I: Olfactory nerve

sense of smell

CN II: Optic nerve

sense of vision