{{Short description|Sensory nerve of the face}} {{Infobox Nerve | Name = Mental nerve | Latin = nervus mentalis | Image = Gray778.png | Caption = Distribution of the [[maxillary nerve|maxillary]] and [[mandibular nerve]]s, and the [[submaxillary ganglion]]. (Mental nerve visible at bottom right, at [[chin]].) | Image2 = Gray784.png | Caption2 = Sensory areas of the head, showing the general distribution of the three divisions of the fifth nerve. (Mental nerve labeled at bottom left, near chin, in yellow.) | Innervates = [[Chin]], [[lower lip]] | BranchFrom = [[Inferior alveolar nerve]] | BranchTo = | MeshName = | MeshNumber = }}
The '''mental nerve''' is a [[sensory nerve]] of the [[face]]. It is a branch of the posterior trunk of the [[inferior alveolar nerve]], itself a branch of the [[mandibular nerve]] (CN V<sub>3</sub>), itself a branch of the [[trigeminal nerve]] (CN V). It provides sensation to the front of the [[chin]] and the [[Lip|lower lip]], as well as the [[gums]] of the anterior mandibular (lower) teeth. It can be blocked with [[Local anesthesia|local anaesthesia]] for procedures on the chin, lower lip, and [[mucous membrane]] of the inner cheek. Problems with the nerve cause chin numbness.
== Structure == The mental nerve is a branch of the posterior trunk of the [[inferior alveolar nerve]]. This is a branch of the mandibular nerve (CN V<sub>3</sub>), itself a branch of the [[trigeminal nerve]] (CN V).<ref name=":3">{{Cite book|last=Gwathmey|first=Kelly G.|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780128111611000177|title=Handbook of Clinical Neurology|publisher=[[Elsevier]]|year=2018|isbn=978-0-12-811161-1|volume=149|pages=257–279|language=en|chapter=17 - Plexus and peripheral nerve metastasis|doi=10.1016/B978-0-12-811161-1.00017-7|pmid=29307357 |issn=0072-9752}}</ref> It emerges from the [[mental foramen]] in the [[Human mandible|mandible]].<ref name=":2">{{Cite book|last1=Clarke|first1=K. W.|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780702027932000116|title=Veterinary Anaesthesia|last2=Trim|first2=C. M.|last3=Hall|first3=L. W.|publisher=[[Saunders (imprint)|Saunders]]|year=2014|isbn=978-0-7020-2793-2|edition=11th|pages=245–311|language=en|chapter=11 - Anaesthesia of the horse|doi=10.1016/B978-0-7020-2793-2.00011-6}}</ref> It divides into three branches beneath the [[depressor anguli oris muscle]]. One branch descends to the skin of the [[chin]]. Two branches ascend to the skin and mucous membrane of the [[lower lip]]. These branches communicate freely with the [[facial nerve]].
== Function == The mental nerve provides sensation to the front of the chin and the lower lip. It also provides sensation to some of the [[gums]] of the anterior mandibular (lower) teeth.
== Clinical significance ==
=== Anaesthesia === The mental nerve can be blocked with [[local anesthesia]]. This can be used in surgery of the [[chin]], the [[Lip|lower lip]], and the buccal mucosa from midline to the second premolar. In animals, it can be used in [[surgery]] of the lower lip,<ref name=":2" /> and lower teeth anterior to the site of administration.<ref name=":0">{{Cite book|last1=Gorrel|first1=Cecilia|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780702049439000077|title=Veterinary Dentistry for the General Practitioner|last2=Andersson|first2=Susanne|last3=Verhaert|first3=Leen|publisher=[[Saunders (imprint)|Saunders]]|year=2013|isbn=978-0-7020-4943-9|edition=2nd|pages=15–29|language=en|chapter=2 - Anesthesia and analgesia|doi=10.1016/B978-0-7020-4943-9.00007-7}}</ref> Local anesthetic is injected into the soft tissue surrounding the [[mental foramen]], or more rarely into the mental foramen itself (although this can cause damage).<ref name=":0" />
=== Chin numbness === Problems with the mental nerve can cause numbness over the chin.<ref name=":3" /> This can be caused by many different illnesses.<ref name=":3" />
=== Reflexes === When the mental nerve is stimulated with electricity, muscles that close the jaw (particularly [[temporalis muscle]] and [[masseter muscle]]) are inhibited.<ref name=":1">{{Cite book|last1=Sandrini|first1=Giorgio|url=https://www.sciencedirect.com/science/article/pii/S0072975210970309|title=Handbook of Clinical Neurology|last2=Rossi|first2=Paolo|publisher=[[Elsevier]]|year=2010|isbn=978-0-444-52139-2|volume=97|pages=367–376|language=en|doi=10.1016/S0072-9752(10)97030-9|pmid=20816436 |issn=0072-9752}}</ref> This is a brainstem [[reflex]].<ref name=":1" />
== References == {{Gray's}} {{Reflist}}
== External links == * {{SUNYAnatomyLabs|23|st|06|10}} - "Anatomy of the Superficial Face - Nerves" * {{LoyolaMedEd|GrossAnatomy/h_n/cn/cn1/cnb3.htm}} * {{NormanAnatomy|cranialnerves}} ({{NormanAnatomyFig|V}})
{{Trigeminal nerve}} {{Portal bar|Anatomy}} {{Authority control}}
{{DEFAULTSORT:Mental Nerve}} [[Category:Nerves]]