Cranial Nerves: there are 12 paired cranial nerves which arise from the brain or brainstem and which are responsible for a variety of critical neurological sensory and motor functions. They include:

• CN I – olfactory nerves; for olfaction (sense of smell)
• CN II – optic nerves; for sight
• CN III – oculomotor nerves; for most eye movements
• CN IV – trochlear nerves; for moving the eyes down and inward
• CN V – trigeminal nerves; for facial sensation and muscles of mastication (chewing muscles)
• CN VI – abducens nerves; for moving the eyes outward
• CN VII – facial nerves; for facial muscle innervation
• CN VIII – vestibulo-cochlear nerves – for hearing and balance
• CN IX – glossopharyngeal nerves – for sensation of the posterior 1/3 of the tongue, tonsils and pharnynx, for swallowing and the gag reflex and for parasympathetic innervation of the parotid gland
• CN X – vagal nerves – for muscles in the mouth and larynx and for parasympathetic innervation of many organs in the body
• CN XI – spinal accessory nerves – for neck movements through the trapezius and sternocleidomastoid muscles
• CN XII – hypoglossal nerves – for tongue movements