Dictionary Definition
cheekbone n : the arch of bone beneath the eye
that forms the prominence of the cheek [syn: zygomatic
bone, mala, malar bone,
jugal
bone, os
zygomaticum]
User Contributed Dictionary
English
Noun
- The small prominent bone of the cheek.
Synonyms
Translations
bone
Extensive Definition
The zygomatic bone came from the latin tearm
zyosislymore meaning malar 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 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 processes,
the frontosphenoidal, orbital, maxillary, and temporal; and four
borders.
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.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.
Process
The zygomatic process is a protrusion from the rest of the skull, like the bumper of a car. Most of it belongs to the zygomatic bone, but there are other bones contributing to it too, namely the frontal bone, maxilla and temporal bone.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 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
Image:Orbital_bones.png|The seven bones which
articulate to form the orbit. Image:Illu facial bones.jpg|Facial
bones.