View source for Foramen ovale (skull)

{{short description|Hole in the sphenoid bone of the skull}}
{{Infobox bone
| Name        = Foramen ovale of sphenoid bone
| Latin       = foramen ovale ossis sphenoidalis
| Image       = File:Gray145.png
| Caption     = [[Sphenoid bone]]. Upper surface. (foramen ovale labeled at left, third from bottom)
| Image2      = File:Gray191.png
| Caption2    = Horizontal section of nasal and orbital cavities.
|PartOf=[[Sphenoid bone]]|System=[[Skeletal system|Skeletal]]}}{{Not to be confused with|Foramen ovale (heart)}}
The '''foramen ovale''' (En: oval window) is a hole in the posterior part of the [[sphenoid bone]], posterolateral to the [[foramen rotundum]]. It is one of the larger of the several holes (the [[Foramina of the skull|foramina]]) in the skull. It transmits the [[mandibular nerve]], a branch of the [[trigeminal nerve]].

== Structure ==
[[File:Base of skull 12.jpg|thumb|left|Foramen ovale]]

The [[foramen]] ovale is an opening  in the greater wing of the [[sphenoid bone]].<ref name=":0">{{Cite journal|last=Ray|first=Biswabina|last2=Gupta|first2=Nirupma|last3=Ghose|first3=Supriya|year=2005|title=Anatomic variations of foramen ovale|url=http://t.kumj.com.np/issue/9/64-68.pdf|journal=Kathmandu University Medical Journal|volume=3|issue=9|pages=64 - 68}}</ref> The foramen ovale is one of two [[cranial foramina]] in the greater wing, the other being the [[foramen spinosum]].<ref name="GRAYS2005">{{cite book|last=Drake|first=Richard L.|title=Gray's anatomy for students|year=2005|publisher=Elsevier/Churchill Livingstone|location=Philadelphia|isbn=978-0-8089-2306-0|author2=Vogl, Wayne |author3=Tibbitts, Adam W.M. Mitchell  |author4=illustrations by Richard |author5= Richardson, Paul }}</ref> {{rp|771}} The foramen ovale is posterolateral to the [[foramen rotundum]] and anteromedial to the [[foramen spinosum]]. Posterior and medial to the foramen is the opening for the [[carotid canal]].<ref name=GRAYS2005 /> {{rp|776}}

=== Contents ===
The following structures pass through foramen ovale: 
* [[mandibular nerve|mandibular nerve (CN V{{sub|3}})]] (a branch of the [[trigeminal nerve|trigeminal nerve (CN V)]])<ref name=":0" />
*[[accessory meningeal artery]]<ref name=":0" />
*[[lesser petrosal nerve]] (a branch of the [[glossopharyngeal nerve]])<ref name=":0" /><ref name="GRAYS2005" /><!-- (note: the lesser superficial petrosal nerve sometimes passes through a special canal ([[Foramen petrosum|''canaliculus innominatus'' of Arnold]]), situated medial to the [[foramen spinosum]]) -->
* an [[emissary vein]] connecting the [[cavernous sinus]] with the [[pterygoid plexus]]<ref name=":0" />
* (occasionally) [[meningeal branch of the mandibular nerve]]<ref name=":0222">{{Cite book |last=Sinnatamby |first=Chummy S. |title=Last's Anatomy |vauthors= |publisher= |year=2011 |isbn=978-0-7295-3752-0 |edition=12th |pages=}}</ref>{{Rp|page=364, 496}}

=== Variation ===
In a study conducted on 100 skulls, the foramen ovale was divided into 2 or 3 components in 4.5% of the cases. The borders of the foramen in some skulls were also irregular and rough. This may suggest, based on radiological images, the presence of morbid changes, which might be the sole anatomical variation in the foramina ovalia of humans.<ref name="Folia">{{cite journal |vauthors=Reymond J, Charuta A, Wysocki J |year=2005 |title=The morphology and morphometry of the foramina of the greater wing of the human sphenoid bone |journal=Folia Morphologica |volume=64 |issue=3 |pages=188–93 |pmid=16228954}}</ref>

In newborn, the foramen ovale is about 3.85 mm and in the adults about 7.2 mm in length. The average maximal length is about 7.48 mm and its average minimal length is 4.17 mm in the adult. The width extends from 1.81 mm in the newborn to 3.7 mm in adults.<ref name="Yanagi">{{cite journal |author=Yanagi S |year=1987 |title=Developmental studies on the foramen rotundum, foramen ovale and foramen spinosum of the human sphenoid bone |journal=The Hokkaido Journal of Medical Science |volume=62 |issue=3 |pages=485–96 |pmid=3610040}}</ref><ref name="AnatAnz">{{cite journal |vauthors=Lang J, Maier R, Schafhauser O |year=1984 |title=Postnatal enlargement of the foramina rotundum, ovale et spinosum and their topographical changes |journal=Anatomischer Anzeiger |volume=156 |issue=5 |pages=351–87 |pmid=6486466}}</ref>

=== Development ===
Similar to other foramina, the foramen ovale differs in shape and size throughout life. In a study using over 350 skulls, the earliest perfect ring-shaped formation of the foramen ovale was observed in the 7th month of fetal life, and the latest in 3 years after birth.<ref name="Yanagi" />

== Clinical significance ==
The foramen ovale is used as the entry point into the skull when conducting a percutaneous rhizotomy using either radio-frequency ablation, balloon compression or glycerol injection. These are performed to treat [[trigeminal neuralgia]]. In the procedure, the electrode is introduced through the cheek of an anesthetized patient and radiologically guided into the foramen ovale, with the intention of partially or fully ablating one or more of the divisions (typically the mandibular) to relieve pain.<ref>{{cite web|last1=Tew|first1=John|title=Percutaneous stereotactic rhizotomy (PSR) for facial pain|url=http://www.mayfieldclinic.com/PE-PSR.htm|website=Mayfield Brain & Spine|access-date=5 December 2016}}</ref>

This entry point is also used to surgically place local electrodes directly on the surface of the [[temporal lobe|mesial temporal lobe]], in order to observe neural activity of patients with suspected focal epilepsy.<ref>{{cite journal | pmid = 16922874 | doi=10.1111/j.1528-1167.2006.00547.x | volume=47 | title=Foramen ovale electrodes can identify a focal seizure onset when surface EEG fails in mesial temporal lobe epilepsy | journal=Epilepsia | pages=1300–7 | last1 = Velasco | first1 = TR | last2 = Sakamoto | first2 = AC | last3 = Alexandre | first3 = V Jr | last4 = Walz | first4 = R | last5 = Dalmagro | first5 = CL | last6 = Bianchin | first6 = MM | last7 = Araújo | first7 = D | last8 = Santos | first8 = AC | last9 = Leite | first9 = JP | last10 = Assirati | first10 = JA | last11 = Carlotti | first11 = C Jr| year=2006 | issue=8 | doi-access =  }}</ref>

== History ==

=== Etymology ===
The name "foramen ovale" comes from the [[Latin]] "oval hole / window".

== See also ==
{{Anatomy-terms}}
* [[Foramina of the skull]]

== References ==
{{Gray's}}
{{Reflist|2}}

== External links ==
* {{SUNYAnatomyLabs|22|os|09|04}}
* {{NormanAnatomy|cranialnerves}} ({{NormanAnatomyFig|IX}})
* {{cite web|url=http://www.tk.de/rochelexikon/pics/s34257.000-1.html|title=Anatomy diagram: 34257.000-1|work= Roche Lexicon - illustrated navigator|publisher= Elsevier|archive-url=https://web.archive.org/web/20140101000000/http://www.tk.de/rochelexikon/pics/s34257.000-1.html|archive-date=2014-01-01}}
* [http://zemlin.shs.uiuc.edu/Skull/slide-Pages/10.htm Adult skull as seen from beneath at uiuc.edu]

{{Skull}}
{{Foramina of skull}}
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[[Category:Foramina of the skull]]