# Pterion

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> Source: https://en.wikipedia.org/wiki/Pterion
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{{Short description|Meeting point between the frontal, parietal, temporal, and sphenoid bones of the skull}}
{{Use dmy dates|date=April 2017}}
{{Infobox anatomy
| Name        = Pterion
| Latin       = pterion
| Image       = Pterion.PNG
| Caption     = Side view of head, showing surface relations of bones (Pterion labeled at center)
| Image2      = Gray188-Sphenoparietal suture.png
| Caption2    = Side view of the skull with arrow pointing to the Pterion
| System      =
| Precursor   =
}}
[[File:Sphenoparietal suture.png|thumb|[Sphenoparietal suture](/source/Sphenoparietal_suture) highlighted in red]]
The '''pterion''' is the region where the [frontal](/source/frontal_bone), [parietal](/source/parietal_bone), [temporal](/source/temporal_bone), and [sphenoid](/source/sphenoid_bone) bones join.<ref>R.M. McMinn.Last's anatomy regional and applied, 9th edition. Edinburgh (UK): Churchill Livingstone; 1994. Page 645</ref> It is located on the side of the [skull](/source/skull), just behind the [temple](/source/temple_(anatomy)). It is also considered to be the weakest part of the skull, which makes it clinically significant, as if there is a [fracture](/source/Bone_fracture) around the pterion it could be accompanied by an [epidural hematoma](/source/epidural_hematoma).

== Structure ==
The pterion is located in the [temporal fossa](/source/temporal_fossa), approximately 2.6&nbsp;cm behind and 1.3&nbsp;cm above the posterolateral margin of the [frontozygomatic suture](/source/frontozygomatic_suture).<ref name="Surface Anatomy">{{cite journal|last=Siyan|first=MA |author2=Louisa J.M. Baillie |author3=Mark D. Stringer|title=Reappraising the surface anatomy of the pterion and its relationship to the middle meningeal artery|journal=Clinical Anatomy|date=April 2012|volume=25|issue=3|pages=330–339|doi=10.1002/ca.21232|pmid=21800374|s2cid=24390399 }}</ref>

It is the junction between four bones:
* the [parietal bone](/source/parietal_bone).
* the [squamous part](/source/Squamous_part_of_temporal_bone) of [temporal bone](/source/temporal_bone).
* the [greater wing](/source/Greater_wing_of_sphenoid_bone) of [sphenoid bone](/source/sphenoid_bone).
* the [frontal bone](/source/frontal_bone).

These bones are typically joined by five [cranial sutures](/source/cranial_sutures):
* the [sphenoparietal suture](/source/sphenoparietal_suture) joins the sphenoid and parietal bones.
* the [coronal suture](/source/coronal_suture) joins the frontal bone to the sphenoid and parietal bones.
* the [squamous suture](/source/squamous_suture) joins the temporal bone to the sphenoid and parietal bones.
* the [sphenofrontal suture](/source/sphenofrontal_suture) joins the sphenoid and frontal bones.
* the [sphenosquamosal suture](/source/sphenosquamosal_suture) joins the sphenoid and temporal bones.

== Clinical significance ==

=== Hematoma ===
The pterion is known as the weakest part of the skull.<ref>{{cite book |last1=Garner |first1=Jeff |last2=Goodfellow |first2=Peter |year=2004 |title=Questions for the MRCS Vivas |url=https://archive.org/details/questionsformrcs00garn |url-access=limited |page=[https://archive.org/details/questionsformrcs00garn/page/n137 123]|isbn=9780340812921 }}</ref>  The anterior division of the [middle meningeal artery](/source/middle_meningeal_artery) runs underneath the pterion.<ref>{{cite web|last=Weston|first=Gabriel|title=Mapping the Body: The Temple|url=https://www.theguardian.com/lifeandstyle/2011/aug/22/mapping-the-body-the-temple|work=The Guardian|access-date=4 April 2012|date=22 August 2011}}</ref> Consequently, a traumatic blow to the pterion may rupture the middle meningeal artery causing an [epidural haematoma](/source/epidural_haematoma). The pterion may also be fractured indirectly by blows to the top or back of the head that place sufficient force on the skull to fracture the pterion.

=== Surgery ===
The pterion is a structural landmark for [neurosurgical](/source/Neurosurgery) approach to middle cerebral artery [aneurysm](/source/aneurysm)s.<ref>{{Cite journal|last1=Urzì|first1=Filippo|last2=Iannello|first2=Annalisa|last3=Torrisi|first3=Antonio|last4=Foti|first4=Pietro|last5=Mortellaro|first5=Nicola Filippo|last6=Cavallaro|first6=Marco|date=2003-04-01|title=Morphological variability of pterion in the human skull|url=https://europepmc.org/article/med/14503657|journal=Italian Journal of Anatomy and Embryology = Archivio Italiano di Anatomia ed Embriologia|volume=108|issue=2|pages=83–117|issn=2038-5129|pmid=14503657}}</ref>

== Etymology ==
The pterion receives its name from the [Ancient Greek](/source/Ancient_Greek) root {{lang|grc|πτερόν}} {{lang|grc-Latn|pteron}}, meaning '[wing](/source/wing)'. In [Greek mythology](/source/Greek_mythology), [Hermes](/source/Hermes), messenger of the gods, was enabled to fly by winged sandals, and wings on his head, which were attached at the pterion.

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

== External links ==
{{Commons category|Pterion}}
* {{SUNYAnatomyFigs|22|01|04}}
* [https://web.archive.org/web/20070109063133/http://face-and-emotion.com/dataface/anatomy/media/Morris_skull-lateralview.jpg Diagram - look for #24] (source [https://web.archive.org/web/20060416081054/http://face-and-emotion.com/dataface/anatomy/skullviews.jsp here])

{{Sutures}}
{{Portal bar|Anatomy}}
{{Authority control}}

Category:Skull
Category:Otorhinolaryngology

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Adapted from the Wikipedia article [Pterion](https://en.wikipedia.org/wiki/Pterion) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Pterion?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.