View source for Zygomatic bone

{{Short description|Facial bone}}
{{Infobox bone
| Name          = Zygomatic bone
| Latin         = os zygomaticum, zygoma
| Image         = Zygomatic bone anterior.png
| Caption       = Position of the zygomatic bone
| Image2        = Zygomatic bone - animation 02.gif
| Caption2      = Animation of the zygomatic bone
| Origins       =
| PartOf        = [[Skull]]
| Insertions    =
| Articulations = [[Maxilla]],  [[temporal bone]], [[sphenoid bone]] and [[frontal bone]]
}}

In the [[human skull]], the '''zygomatic bone''' (from {{langx|grc|ζῠγόν|zugón|yoke}}), also called '''cheekbone''' or '''malar bone''', is a paired [[irregular bone]], situated at the upper and lateral part of the face and forming part of the lateral wall and floor of the [[orbit (anatomy)|orbit]], of the [[temporal fossa]] and the [[infratemporal fossa]]. It presents a malar and a temporal surface; four [[Process (anatomy)|processes]] (the frontosphenoidal, orbital, maxillary, and temporal), and four borders.

== Etymology ==
The term ''zygomatic'' derives from the [[Ancient Greek]] {{lang|grc|Ζυγόμα}}, ''zygoma'', meaning "yoke".  The zygomatic bone is occasionally referred to as the [[zygoma]], but this term may also refer to the [[zygomatic arch]].

== Structure ==

=== Surfaces ===
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 major muscle|zygomaticus muscle]].

The ''temporal surface'', directed posteriorly and medially, is concave, presenting medially a rough, triangular area, for articulation with the maxilla (articular surface), 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]].

The ''orbital surface'' forms the lateral part and some of the inferior part of the bony orbit. The [[zygomatic nerve]] passes through the zygomatic-orbital foramen on this surface. The lateral palpebral ligament attaches to a small protuberance called the orbital tubercle.

=== Processes ===
Each zygomatic bone is diamond-shaped and composed of three processes with similarly named associated bony articulations: frontal, temporal, and maxillary. Each process of the zygomatic bone forms important structures of the skull.

The orbital surface of the frontal process of the zygomatic bone forms the anterior lateral orbital wall, with usually a small paired foramen, the zygomaticofacial foramen opening on its lateral surface. The temporal process of the zygomatic bone forms the zygomatic arch along with the zygomatic process of the temporal bone, with a paired zygomaticotemporal foramen present on the medial deep surface of the bone. The orbital surface of the maxillary process of the zygomatic bone forms a part of the infraorbital rim and a small part of the anterior part of the lateral orbital wall.<ref>{{cite book|title=Illustrated Anatomy of the Head and Neck|last1=Fehrenbach|last2=Herring|publisher=Elsevier|date=2012|page=54}}</ref>

=== Orbital process ===
The '''orbital process''' is a thick, strong plate, projecting backward and medialward from the orbital margin. Its ''antero-medial surface'' forms, by its junction with the orbital surface of the [[maxilla]] and with the great wing of the [[Sphenoid bone|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]].
* Its ''postero-lateral surface,'' smooth and convex, forms parts of the temporal and infratemporal fossae.
* Its ''anterior margin,'' smooth and rounded, is part of the circumference of the orbit.
* Its ''superior'' ''margin,'' rough, and directed horizontally, articulates with the frontal bone behind the zygomatic process.
* Its ''posterior margin'' is serrated for articulation, with the great wing of the sphenoid and the orbital surface of the maxilla.

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.

=== 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]].

=== Articulations ===
The zygomatic bone articulates with the [[frontal bone]], [[sphenoid bone]], and paired [[temporal bone]]s, and [[maxilla|maxillary bones]].

=== Development ===
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 consisted of two parts, an orbital and a malar.

== Society and culture ==
{{multiple image
 | width = 125
 | image1 = Natasha Poly in Zac Posen Spring 2009, Photo by Ed Kavishe fashionwirepress.jpg
 | image2 = Lincoln O-21 by Marsh, 1860.jpg
 | footer = The high cheekbones of model [[Natasha Poly]] (left) and [[Abraham Lincoln]] (right)
}}

Zygomatic arches, also known as high cheek bones, are considered [[physical attractiveness|physically attractive]] in some cultures, in both males and females.<ref name="Sex and Society">{{cite book|title=Sex and Society|url=https://books.google.com/books?id=aVDZchwkIMEC&pg=PA91|access-date=2 November 2012|date=September 2009|publisher=Marshall Cavendish|isbn=978-0-7614-7906-2|page=91}}</ref><ref name="Cartwright2000">{{cite book|last=Cartwright|first=John|title=Evolution and Human Behavior|url=https://books.google.com/books?id=FWnb2oFnS6IC&pg=PA259|access-date=2 November 2012|date=24 July 2000|publisher=MIT Press|isbn=978-0-262-53170-2|page=259}}</ref>

Ancient [[China|Chinese]] sculptures of goddesses typically have a "broad forehead, raised [[eyebrows]], high cheekbones, and large, sensuous mouth".<ref name="HowardLi2006">{{cite book|last1=Howard|first1=Angela Falco|last2=Li|first2=Song|last3=Wu|first3=Hung|author3-link=Wu Hung|last4=Yang|first4=Hong |title=Chinese Sculpture|url=https://books.google.com/books?id=PGuPsNCaJdwC&pg=PA1|access-date=2 November 2012|date=28 April 2006|publisher=Yale University Press|isbn=978-0-300-10065-5|page=1}}</ref> Similarly, many depictions of Qin warriors in the [[Terracotta Army]] are depicted with "broad [[forehead]]s, high cheekbones, large eyes, thick eyebrows, and stiff [[beards]]."<ref name="HowardLi2006" />

For this reason some individuals undergo [[cheek augmentation]], a form of [[cosmetic surgery]].<ref name="SiemionowEisenmann-Klein2010">{{cite book|last=Siemionow|first=Maria Z.|title=Plastic and Reconstructive Surgery|url=https://books.google.com/books?id=9WFZ1pE0AFMC&pg=PA48|access-date=2 November 2012|date=19 March 2010|publisher=Springer|isbn=978-1-84882-512-3|page=48}}</ref>

== Animals ==
The zygomatic is [[Homology (biology)|homologous]] to the [[jugal]] bone of other [[tetrapods]].

=== Non-mammalian vertebrates ===
[[File:Gegenbaur 1870 skull homology color.png|thumb|Diagram showing homologous bones of the skulls of a [[Monitor lizard]] and a [[Crocodile]].  Jugal bone labelled ''Ju'', in pale green, at centre left.]]
{{Stack|[[File:The Childrens Museum of Indianapolis - Jugal from Edmontosaurus - detail.jpg|alt=|thumb|upright=0.75|This jugal bone from an [[Edmontosaurus]] is over three feet (1 meter) long]]}}

In non-[[mammal]]ian vertebrates, the zygomatic bone is referred to as the [[jugal]] bone, since these animals have no zygomatic arch. It is  found in most [[reptile]]s, [[amphibian]]s, and [[bird]]s. It is connected to the [[quadratojugal]] and [[maxilla]], as well as other bones, which may vary by species.

This bone is considered key in the determination of general traits of the skull, as in the case of creatures, such as [[dinosaur]]s in [[paleontology]], whose entire skull has not been found. In [[coelacanth]]s and early [[tetrapod]]s the bone is relatively large. Here, it is a plate-like bone forming the lower margin of the orbit and much of the side of the face. In [[ray-finned fish]]es it is reduced or absent, and the entire cheek region is generally small. The bone is also absent in living [[amphibian]]s.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 217–241|isbn= 0-03-910284-X}}</ref>

With the exception of [[turtle]]s, the jugal bone in [[reptile]]s forms a relatively narrow bar separating the orbit from the inferior [[temporal fenestra]], of which it may also form the lower boundary. The bone is similarly reduced in [[bird]]s. In mammals, it takes on broadly the form seen in humans, with the bar between the orbit and fenestra vanishing entirely, and only the lower boundary of the fenestra remaining, as the zygomatic arch.<ref name=VB/>

== Additional images ==
{{Gallery|width=150|height=150
 |File:Gray165.png|Left zygomatic bone, malar surface
 |File:Gray166.png|Left zygomatic bone, temporal surface
 |File:Gray189.png|Left infratemporal fossa
}}
{{Clear}}

== See also ==
{{Portal|Anatomy}}
{{Anatomy terms}}
* [[Treacher Collins syndrome]]
* [[Zygoma fracture]]
* [[Zygomatic arch]]
* [[Tripod fracture|Zygomatic complex fracture]]
* [[Zygomatic fossa]]

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

== External links ==
{{Commons}}
* {{EMedicine|article|835401|Facial Bone Anatomy}}

{{OrbitalBones}}
{{Facial bones}}
{{Authority control}}

[[Category:Skull bones]]
[[Category:Facial features]]
[[Category:Irregular bones]]