Algonquin College
8.3 - Cranial Nerves
Cranial nerves extend from the base of the brain and cervical spinal cord and control several functions of both the autonomic and somatic nervous systems. The cranial nerves are a part of the peripheral nervous system and most are mixed nerve, although some are purely sensory or motor.

There are twelve pairs of cranial nerves which project from the skull through openings called foramina (each opening is called a foramen). Each cranial nerve is numbered in roman numerals (I through XII) according to where it exits the brain. The exit for cranial nerve I is the most superior and the exit for cranial nerve XII is the most inferior.

Cranial Nerves
Figure 8.3.1

By Brain_human_normal_inferior_view.svg: Patrick J. Lynch, medical illustrator derivative work: Beao (Brain_human_normal_inferior_view.svg) [CC-BY-2.5 (www.creativecommons.org/licenses/by/2.5)], via Wikimedia Commons

Table 8.3.1 - The Functions of the Cranial Nerves

# Name Sensory Functions Motor Functions
I Olfactory Sensory information for smell (olfaction) None
II Optic Sensory information for sight (vision) None
III Oculomotor None Motor information for eye muscles controlling movement of the eyeball, eyelid, lens shape and pupil size
IV Trochlear None Motor information for the external oblique eye muscle
V Trigeminal Sensory information from the facial skin and mucosa of the oral and nasal cavities Motor information for chewing muscles
VI Abducens None Motor information for lateral movement of the eye
VII Facial Sensory information for anterior tongue taste buds Motor information for facial expression muscle and salivary glands
VIII Vestibulocochlear Sensory information from the ear for balance (vestibular branch) and hearing (cochlear branch) None
IX Glossopharyngeal Sensory information from the posterior tongue taste buds and carotid artery pressure receptors Motor information for the pharynx for swallowing and salivation
X Vagus Sensory and motor information for the pharynx, larynx, and visceral organs of the thorax and abdomen. Most motor fibers are parasympathetic
XI Accessory None Motor information for the sternocleidomastoid and trapezius muscles of the neck
XII Hypoglossal Sensory information from the tongue Motor information for tongue movements

Click here for an digital activity on the cranial nerves