Cranial nerves
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Reverted edits by [[Special:Contributions/222.127.154.144|222.127.154.144]] to last version by 66.192.63.133 (using [[WP:HG|Huggle]])
'''Cranial nerves''' are [[nerve]]s that emerge directly from the [[brain]] in contrast to [[spinal nerve]]s which emerge from segments of the [[spinal cord]]. Although thirteen cranial nerves in [[human anatomy|humans]] fit this description, twelve are conventionally recognized. The nerves from the third onward arise from the [[brain stem]].
Except for the tenth and the eleventh nerve, they primarily serve the [[motor system|motor]] and [[sensory system|sensory]] systems of the [[Head and neck anatomy|head and neck]] region. However, unlike [[peripheral nerve]]s which are separated to achieve [[segmental innervation]], cranial nerves are divided to serve one or a few specific functions in wider anatomical territories.
==Names of Nerves==
The 12 pairs of cranial nerves are traditionally abbreviated by the corresponding [[Roman numeral]]s. They are numbered according to where their [[nucleus (neuroanatomy)|nuclei]] lie in the brain stem, e.g. Cranial Nerve III (the Oculomotor nerve) leaves the brainstem at a higher position than Cranial nerve XII, whose origin is located more caudally (lower) than the other cranial nerves.
{| class="wikitable"
| '''#''' || '''Name''' || '''Nuclei''' || '''Function'''
|-
| 0 || [[Cranial nerve zero]] (''CN0 is not traditionally recognized.'')<ref>Fuller GN, Burger PC. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2286018&dopt=Abstract "Nervus terminalis (cranial nerve zero) in the adult human."] ''Clin Neuropathol'' 9, no. 6 (Nov-Dec 1990): 279-283.</ref>
|| [[olfactory trigone]], [[medial olfactory gyrus]], and [[lamina terminalis]] ||
Still controversial
New research indicates CN0 may play a role in the detection of pheromones <ref>Merideth, Michael. [http://chemse.oxfordjournals.org/cgi/content/full/26/4/433 "Human Vomeronasal Organ Function."] ''Oxford Journals: Chemical Senses'', 2001.</ref><ref>Fields, R. Douglas. [http://www.sciammind.com/article.cfm?articleID=792DDD7C-E7F2-99DF-397429B8BB8ED7ED&ref=sciam "Sex and the Secret Nerve."] ''Scientific American Mind'', February 2007.</ref>
|-
| I || [[Olfactory nerve]] || [[Anterior olfactory nucleus]] || Transmits the sense of smell; Located in [[olfactory foramina]] of ethmoid
|-
| II || [[Optic nerve]] || [[Lateral geniculate nucleus]] || Transmits visual information to the brain; Located in [[optic canal]]
|-
| III || [[Oculomotor nerve]] || [[Oculomotor nucleus]], [[Edinger-Westphal nucleus]] || Innervates [[levator palpebrae superioris]], [[superior rectus]], [[medial rectus]], [[inferior rectus]], and [[inferior oblique]], which collectively perform most eye movements; Located in [[superior orbital fissure]]
|-
| IV || [[Trochlear nerve]] || [[Trochlear nucleus]] || Innervates the [[superior oblique muscle]], which depresses, pulls laterally, and [[intort]]s the eyeball; Located in [[superior orbital fissure]]
|-
| V || [[Trigeminal nerve]] || [[Principal sensory trigeminal nucleus]], [[Spinal trigeminal nucleus]], [[Mesencephalic trigeminal nucleus]], [[Trigeminal motor nucleus]] || Receives sensation from the face and innervates the [[muscles of mastication]]; Located in [[superior orbital fissure]] (ophthalmic branch), [[foramen rotundum]] (maxillary branch), and [[foramen ovale]] (mandibular branch)
|-
| VI || [[Abducens nerve]] || [[Abducens nucleus]] || Innervates the [[lateral rectus]], which abducts the eye; Located in [[superior orbital fissure]]
|-
| VII || [[Facial nerve]] || [[Facial nucleus]], [[Solitary nucleus]], [[Superior salivary nucleus]] || Provides motor innervation to the [[muscles of facial expression]] and [[stapedius]], receives the special sense of taste from the [[anterior 2/3 of the tongue]], and provides [[secretomotor]] innervation to the [[salivary gland]]s (except parotid) and the [[lacrimal gland]]; Located and runs through [[internal acoustic canal]] to [[facial canal]] and exits at [[stylomastoid foramen]]
|-
| VIII || [[Vestibulocochlear nerve]] (or ''auditory-vestibular nerve'' or ''statoacustic nerve'') || [[Vestibular nuclei]], [[Cochlear nuclei]] || Senses sound, rotation and gravity (essential for balance & movement; Located in [[internal acoustic canal]]
|-
| IX || [[Glossopharyngeal nerve]] || [[Nucleus ambiguus]], [[Inferior salivary nucleus]], [[Solitary nucleus]] || Receives taste from the posterior 1/3 of the tongue, provides secretomotor innervation to the parotid gland, and provides motor innervation to the [[stylopharyngeus]] (essential for tactile, pain, and thermal sensation). Sensation is relayed to opposite thalamus and some hypothalamic nuclei. Located in [[jugular foramen]]
|-
| X || [[Vagus nerve]] || [[Nucleus ambiguus]], [[Dorsal motor vagal nucleus]], [[Solitary nucleus]] || Supplies branchiomotor innervation to most laryngeal and pharyngeal muscles; provides [[parasympathetic]] fibers to nearly all thoracic and abdominal viscera down to the [[splenic flexure]]; and receives the special sense of taste from the epiglottis. A major function: controls muscles for voice and resonance and the soft palate. Symptoms of damage: [[dysphagia]] (swallowing problems). Located in [[jugular foramen]]
|-
| XI || [[Accessory nerve]] (or ''cranial accessory nerve'' or ''spinal accessory nerve'') || [[Nucleus ambiguus]], [[Spinal accessory nucleus]] || Controls muscles of the neck and overlaps with functions of the vagus. Examples of symptoms of damage: inability to shrug, weak head movement, [[velopharyngeal insufficiency]]; Located in [[jugular foramen]]
|-
| XII || [[Hypoglossal nerve]] || [[Hypoglossal nucleus]] || Provides motor innervation to the muscles of the tongue and other glossal muscles. Important for swallowing (bolus formation) and speech articulation. Located in [[hypoglossal canal]]
|}
==Cranial nerves in non-human vertebrates==
Human cranial nerves are [[evolution]]arily [[homology (biology)|homologous]] to those found in many other [[vertebrate]]s.
Cranial nerves XI and XII evolved in the common ancestor to [[amniote]]s (non-amphibian tetrapods) thus totalling twelve pairs. These characters are [[synapomorphies]] for their respective [[clades]]. In some primitive cartilagenous fishes, such as the [[dogfish]] (''Squalos acanthos''), there is a terminal nerve numbered [[cranial nerve 0|zero]] (as it exits the brain before the first cranial nerve).
==Mnemonic devices==
As the list is important to keep in mind during the examination of the nervous system, there are many [[mnemonic]] devices in circulation to help remember the names and order of the cranial nerves. Because the mind recalls rhymes well, the best mnemonics often use rhyming schemes. The best known example is, "'''''O'''n '''O'''ld '''O'''lympus' '''T'''owering '''T'''ops '''A''' '''F'''inn '''A'''nd '''G'''erman '''V'''iewed '''S'''ome '''H'''ops'',"<ref name="pmid2254946">{{cite journal |author=Herlevich NE |title=Reflecting on old Olympus' towering tops |journal=Journal of ophthalmic nursing & technology |volume=9 |issue=6 |pages=245–6 |year=1990 |pmid=2254946 |doi= |accessdate=2007-11-06}}</ref> where '''A'''nd represents ''auditory vestibular'' and '''S'''ome represents ''spinal accessory''. The version most used in most Anatomy textbooks is "'''O'''hh, '''O'''hh, '''O'''h, '''T'''o '''T'''ouch '''A'''nd '''F'''eel '''V'''ery '''G'''ood '''V'''elvet, '''AH'''".
For additional memonics, see [[b:Transwiki:List of mnemonics for the cranial nerves]]
==See also==
* [[Cranial nerve nucleus]]
* [[List of mnemonics for the cranial nerves]]
==External links==
*[http://icarus.med.utoronto.ca/NeuroExam/ Examination of the cranial nerves] - [[University of Toronto]] Medicine
*{{NormanAnatomy|cranialnerves}}
*[http://www.rahulgladwin.com/blog/2006/07/cranial-nerves-and-cranial.html CN Medical Notes on rahulgladwin.com]
*[http://remus.rutgers.edu/~emtklein/anatomy/cn.html Information about the Cranial Nerves]
==References==
{{Refimprove|date=January 2008}}
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{{Cranial nerves}}
[[Category:Peripheral nervous system]]
[[Category:Cranial nerves|*]]
[[ar:أعصاب قحفية]]
[[da:Kranienerve]]
[[de:Hirnnerv]]
[[es:Par craneal]]
[[fr:Nerf crânien]]
[[ko:뇌신경]]
[[hr:Mozgovni živci]]
[[it:Nervi cranici]]
[[he:עצבי הגולגולת]]
[[lt:Galviniai nervai]]
[[nl:Hersenzenuw]]
[[ja:脳神経]]
[[no:Hjernenerve]]
[[pl:Nerwy czaszkowe]]
[[pt:Nervos cranianos]]
[[ru:Черепномозговые нервы]]
[[sk:Hlavový nerv]]
[[fi:Aivohermo]]
[[te:కపాల నాడులు]]
[[th:เส้นประสาทสมอง]]
[[vi:Thần kinh sọ não]]
[[zh:脑神经]]
[[sv:kranialnerv]]