In
anatomy
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...
, the zygomatic arch, or cheek bone, is a part of the
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
formed by the
zygomatic process of the
temporal bone (a bone extending forward from the side of the skull, over the opening of the ear) and the temporal
process of the
zygomatic bone (the side of the cheekbone), the two being united by an oblique
suture
Suture, literally meaning "seam", may refer to:
Arts, entertainment, and media
* ''Suture'' (album), a 2000 album by American Industrial rock band Chemlab
* ''Suture'' (film), a 1993 film directed by Scott McGehee and David Siegel
* Suture (ban ...
(the
zygomaticotemporal suture
The zygomaticotemporal suture (or temporozygomatic suture) is the cranial suture between the zygomatic bone and the temporal bone. This is part of the zygomatic arch. Movement at the suture decreases with development during aging. It has a complex ...
);
the
tendon
A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...
of the
temporal muscle
In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomat ...
passes medial to (i.e. through the middle of) the arch, to gain insertion into the
coronoid process of the mandible
In human anatomy, the mandible's coronoid process (from Greek ''korōnē'', denoting something hooked) is a thin, triangular eminence, which is flattened from side to side and varies in shape and size. Its anterior border is convex and is continuou ...
(jawbone).
The jugal point is the point at the anterior (towards face) end of the upper border of the zygomatic arch where the
masseteric and
maxillary edges meet at an angle, and where it meets the process of the zygomatic bone.
The arch is typical of ''
Synapsida'' (“fused arch”), a
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...
of
amniotes that includes
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
s and their extinct relatives, such as ''
Moschops'' and ''
Dimetrodon''.
Structure
The zygomatic process of the temporal arises by two roots:
* an ''anterior'', directed inward in front of the
mandibular fossa, where it expands to form the articular tubercle.
* a ''posterior'', which runs backward above the
external acoustic meatus and is continuous with the supramastoid crest.
The upper border of the arch gives attachment to the
temporal fascia;
the lower border and medial surface give origin to the
masseter.
Society and culture
High cheekbones are pronounced zygomatic arches, causing the upper part of the cheeks to jut out and form a line cut into the sides of the face. High cheekbones, forming a
symmetrical face shape, are very common in
fashion models and may be considered a
beauty trait in both males and females within Eurocentric beauty standards.
Etymology
The term ''zygomatic'' derives from the Greek ζύγωμα zygōma, meaning "bolt, bar", derived from ζυγο-, "yoke, join". The Greek word was already used with this anatomical sense by
Galen
Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be o ...
(2.437, 746) in the 2nd century AD. The zygomatic arch is occasionally referred to as the
zygoma, but this term usually refers to the zygomatic bone or occasionally the
zygomatic process.
Other animals
The zygomatic arch is significant in
evolutionary biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life ...
, as it is part of the structures derived from the ancestral single
temporal fenestra of the
synapsid ancestor of
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
s.
Additional images
File:Gray137.png, Left temporal bone, outer surface
File:Gray165.png, Left zygomatic bone, malar surface
File:Gray187.png, Base of skull, inferior surface
File:Gray382.png, The temporalis; the zygomatic arch and masseter have been removed.
File:Gray1024.png, Dissection, showing salivary glands of right side
File:Sygomafracture.png, Fracture of the zygomatic arch as seen on plain X-ray
File:Slide6JAN.JPG, Zygomatic arch, base of skull
See also
*
Zygoma fracture
*
Zygomasseteric system
The zygomasseteric system (or zygomasseteric structure) in rodents is the anatomical arrangement of the masseter muscle of the jaw and the zygomatic arch of the skull. The anteroposterior or propalinal (front-to-back) motion of the rodent jaw is ...
*
Zygomatic complex fracture
*
Zygomaticotemporal suture
The zygomaticotemporal suture (or temporozygomatic suture) is the cranial suture between the zygomatic bone and the temporal bone. This is part of the zygomatic arch. Movement at the suture decreases with development during aging. It has a complex ...
References
External links
* ()
*
{{Authority control
Skull