Masseter muscle
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2008-07-17T00:35:17Z
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Reverted edits by [[Special:Contributions/72.75.200.67|72.75.200.67]] to last version by Scohoust (using [[WP:HG|Huggle]])
{{Infobox Muscle |
Name = {{PAGENAME}} |
Latin = musculus masseter |
GraySubject = 109 |
GrayPage = 385 |
Image = Illu_head_neck_muscle.jpg |
Caption = Muscles of the head and neck. |
Image2 = Gray1024.png |
Caption2 = Dissection, showing salivary glands of right side. (Masseter visible at center.) |
Width = 300 |
Origin = [[zygomatic arch]] and [[maxilla]] |
Insertion = [[coronoid process]] and [[ramus of mandible]] |
Blood = [[masseteric artery]] |
Nerve = [[masseteric nerve]] (V3) |
Action = [[Elevation (kinesiology)|elevation]] (as in closing of the mouth) and [[Retraction (kinesiology)|retraction]] of [[ mandible]] |
Antagonist = [[Platysma muscle]] |
MeshName = |
MeshNumber = |
DorlandsPre = m_22 |
DorlandsSuf = 12549768 |
}}
In human anatomy, the '''masseter''' is one of the [[Mastication#Muscles_of_mastication|muscles of mastication]].
It is particularly powerful in [[herbivores]] to assist when they are chewing plants.
==Origin and insertion of the two heads==
The masseter is a thick, somewhat quadrilateral muscle, consisting of two portions, superficial and deep.
The fibers of the two portions are continuous at their insertion. The masseter muscle is sometimes the target of plastic [[jaw reduction]] surgery.
===Superficial===
The ''superficial portion'', the larger, arises by a thick, tendinous [[aponeurosis]] from the [[zygomatic process]] of the [[maxilla]], and from the anterior two-thirds of the lower border of the [[zygomatic arch]].
Its fibers pass downward and backward, to be inserted into the angle and lower half of the lateral surface of the [[ramus]] of the [[mandible]].
===Deep===
The ''deep portion'' is much smaller, and more muscular in texture.
It arises from the posterior third of the lower border and from the whole of the medial surface of the zygomatic arch
Its fibers pass downward and forward, to be inserted into the upper half of the ramus and the lateral surface of the [[coronoid process]] of the mandible.
The deep portion of the muscle is partly concealed, in front, by the superficial portion; behind, it is covered by the [[parotid gland]].
==Innervation==
Along with the other three [[Mastication#Muscles_of_mastication|muscles of mastication]] ([[temporalis]], [[medial pterygoid muscle| medial pterygoid]] and [[lateral pterygoid]]), the masseter is innervated by the [[mandibular nerve|mandibular division]] of the [[trigeminal nerve]].
==Additional images==
<gallery>
Image:Gray137.png|Left temporal bone. Outer surface.
Image:Gray141.png|Left temporal bone. Inferior surface.
Image:Gray166.png|Left zygomatic bone. Temporal surface.
Image:Gray176.png|Mandible. Outer surface. Side view.
Image:Gray187.png|Base of skull. Inferior surface.
Image:Gray508.png|The arteries of the face and scalp.
Image:Gray557.png|Veins of the head and neck.
Image:Gray781.png|Mandibular division of the trifacial nerve.
Image:Musculusmasseter.png|Muscles of the head, face, and neck.
</gallery>
==External links==
* {{MuscleLoyola|mass}}
* {{GPnotebook|-100270003}}
* {{eMedicineDictionary|Masseter+muscle}}
{{muscle-stub}}
{{Muscles of head}}
[[Category:Muscles of the head and neck]]
[[ar:عضلة ماضغة]]
[[de:Musculus masseter]]
[[es:Masetero]]
[[fr:Muscle masséter]]
[[it:Massetere]]
[[he:שריר המלעס]]
[[hu:Rágóizom]]
[[nl:Musculus masseter]]
[[ja:咬筋]]
[[pl:Mięsień żwacz]]
[[pt:Masseter]]
[[sr:Масетерични мишић]]
[[sl:Žvekalka]]
[[sh:Maseterični mišić]]
[[fi:Ulompi puremalihas]]
[[zh:嚼肌]]