Cranial nerves (Table)

Cranial nerves

The following table includes the basic information required on the cranial nerves. The cranial nerves are actually very complex and this is a very simplified overview. Questions regarding their origin and function are common.

Number	Nerve	Origin	Skull exit	Modality	Functions
I	Olfactory	Telencephalon	Cribiform plate	Sensory	Sense of smell
II	Optic	Diencephalon	Optic foramen	Sensory	Vision
III	Oculomotor	Midbrain	Superior orbital fissure	Motor	Eye movement, pupillary constriction, lens accommodation
IV	Trochlear	Midbrain	Superior orbital fissure	Motor	Eye movement
V	Trigeminal	Pons	Superior orbital fissure (ophthalmic V1) Round foramen (maxillary V2) Oval foramen (mandibular V3)	Mixed	Chewing, sensation of anterior 2/3 of scalp, tenses tympanic membrane*
VI	Abducens	Pons	Superior orbital fissure	Motor	Eye movement
VII	Facial	Pons	Internal auditory canal	Mixed	Facial expression, taste anterior 2/3 of tongue, tension on stapes*
VIII	Vestibulocochlear nerve	Pons	Internal auditory canal	Sensory	Hearing
IX	Glossopharyngeal nerve	Medulla	Jugular foramen	Mixed	Taste posterior 1/3 of tongue, elevation of larynx and pharynx, swallowing
X	Vagus	Medulla	Jugular foramen	Mixed	Swallowing, voice production, parasympathetic supply to nearly all thoracic and abdominal viscera
XI	Accessory nerve	Medulla	Jugular foramen	Motor	Shoulder shruging and head turning
XII	Hypoglossal nerve	Medulla	Hypoglossal canal	Motor	Tongue movement

* The tension on the stapes and tympanic membrane act to dampen loud noises

Posted in: Notes : Neuroscience