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{{Infobox Bone |
Name = {{PAGENAME}} |
Latin = os zygomaticum, zygoma |
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Image = Gray164.png |
Caption = Left zygomatic bone ''in situ.'' |
Image2 = Gray995.png |
Caption2 = Side view of the teeth and jaws. (Zygomatic visible in center.) |
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Articulations = |
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The '''zygomatic bone''' ('''malar bone''') is a paired bone of the human [[skull]]. It articulates with the [[maxilla]], the [[temporal bone]], the [[sphenoid bone]] and the [[frontal bone]]. It forms part of the [[Orbit (anatomy)|orbit]] and is commonly referred to as the cheekbone. It is situated at the upper and lateral part of the face: it forms the prominence of the cheek, part of the lateral wall and floor of the orbit, and parts of the temporal and infratemporal fossae [Fig. 1]. It presents a malar and a temporal surface; four [[Process (anatomy)|processes]], the frontosphenoidal, orbital, maxillary, and temporal; and four borders.
== Surfaces Code==
<pre>
The ''malar surface'' is convex and perforated near its center by a small aperture, the [[zygomaticofacial foramen]], for the passage of the zygomaticofacial nerve and vessels; below this foramen is a slight elevation, which gives origin to the [[Zygomaticus]].
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The ''temporal surface'', directed backward and medialward, is concave, presenting medially a rough, triangular area, for articulation with the maxilla, and laterally a smooth, concave surface, the upper part of which forms the anterior boundary of the temporal fossa, the lower a part of the [[infratemporal fossa]]. Near the center of this surface is the [[zygomaticotemporal foramen]] for the transmission of the [[zygomaticotemporal nerve]].
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== Processes ==
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The ''frontosphenoidal process'' is thick and serrated, and articulates with the [[Zygomatic_process of frontal bone|zygomatic process]] of the frontal bone. On its orbital surface, just within the orbital margin and about 11 mm below the zygomaticofrontal suture is a tubercle of varying size and form, but present in 95 per cent of skulls (Whitnall 43).
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The ''orbital process'' is a thick, strong plate, projecting backward and medialward from the orbital margin.
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* Its ''antero-medial surface'' forms, by its junction with the orbital surface of the maxilla and with the great wing of the [[sphenoid]], part of the floor and lateral wall of the orbit. On it are seen the orifices of two canals, the [[zygomatico-orbital foramina]]; one of these canals opens into the [[temporal fossa]], the other on the malar surface of the bone; the former transmits the [[zygomaticotemporal]], the latter the [[zygomaticofacial nerve]].
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* Its ''postero-lateral surface,'' smooth and convex, forms parts of the temporal and infratemporal fossae.
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* Its ''anterior margin,'' smooth and rounded, is part of the circumference of the orbit.
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* Its ''superior'' ''margin,'' rough, and directed horizontally, articulates with the frontal bone behind the zygomatic process.
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* Its ''posterior margin'' is serrated for articulation, with the great wing of the sphenoid and the orbital surface of the maxilla.
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* At the angle of junction of the sphenoidal and maxillary portions, a short, concave, non-articular part is generally seen; this forms the anterior boundary of the inferior orbital fissure: occasionally, this non-articular part is absent, the fissure then being completed by the junction of the maxilla and sphenoid, or by the interposition of a small sutural bone in the angular interval between them.
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The ''maxillary process'' presents a rough, triangular surface which articulates with the maxilla.
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The ''temporal process'', long, narrow, and serrated, articulates with the zygomatic process of the temporal.
</pre>
== Borders ==
The ''antero-superior'' or ''orbital'' border is smooth, concave, and forms a considerable part of the circumference of the orbit.
The ''antero-inferior'' or ''maxillary'' border is rough, and bevelled at the expense of its inner table, to articulate with the maxilla; near the orbital margin it gives origin to the [[Quadratus labii superioris]].
The ''postero-superior'' or ''temporal'' border, curved like an italic letter ''f,'' is continuous above with the commencement of the temporal line, and below with the upper border of the zygomatic arch; the temporal fascia is attached to it.
The ''postero-inferior'' or ''zygomatic border'' affords attachment by its rough edge to the [[Masseter]].
==Ossification==
The zygomatic bone is generally described as [[Ossification|ossifying]] from three centers - one for the malar and two for the orbital portion; these appear about the eighth week and fuse about the fifth month of fetal life.
Mall describes it as being ossified from one center which appears just beneath and to the lateral side of the orbit.
After birth, the bone is sometimes divided by a horizontal suture into an upper larger, and a lower smaller division.
In some [[quadrumana]] the zygomatic bone consists of two parts, an orbital and a malar.
== Articulations ==
The zygomatic articulates with ''four'' bones: the frontal, sphenoidal, temporal, and maxilla.
==Additional illustrations==
<gallery>
Image:Illu facial bones.jpg|Facial bones.
Image:Gray165.png|Left zygomatic bone. Malar surface.
Image:Gray166.png|Left zygomatic bone. Temporal surface.
Image:Gray167.png|Articulation of left palatine bone with maxilla.
Image:Gray188.png|Side view of the skull.
Image:Gray189.png|Left infratemporal fossa.
Image:Gray190.png|The skull from the front.
Image:Gray191.png|Horizontal section of nasal and orbital cavities.
</gallery>
== Beauty ==
High cheek bones are seen as a sign of beauty in many cultures and is a characteristic of many high fashion [[models]].
== See also ==
*[[Bone#Terminology|Bone terminology]]
*[[Terms for anatomical ___location]]
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{{Gray's}}
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{{Facial bones}}
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[[Category:Skeletal system]]
[[Category:Skull]]
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[[cs:Kost lícní]]
[[de:Jochbein]]
[[es:Hueso cigomático]]
[[eo:Zigomo]]
[[fr:Os zygomatique]]
[[it:Osso zigomatico]]
[[lt:Skruostakaulis]]
[[nl:Jukbeen]]
[[ja:頬骨]]
[[pl:Kość jarzmowa]]
[[sk:Jarmová kosť]]
[[sv:Okben]]
[[zh:颧骨]]
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