Omohyoid muscle
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{{Muscle infobox |
Name = Omohyoid muscle |
Latin = musculus omohyoideus |
GraySubject = 112 |
GrayPage = 392 |
Image = Gray1210.png |
Caption = Side of neck, showing chief surface markings. (Omohyoideus visible at center.) |
Image2 = Musculus omohyoideus.png |
Caption2 = Muscles of the neck. Anterior view. Omohyoid is labeled on both sides. |
Origin = [[Upper border of the scapula]] |
Insertion = [[Hyoid bone]] |
Action = Depresses the larynx and hyoid bone. Also carries hyoid bone backward and to the side. |
Blood = |
Nerve = [[Ansa cervicalis]] |
MeshName = |
MeshNumber = |
DorlandsPre = m_22 |
DorlandsSuf = 12549956 |
}}
The '''omohyoid muscle''' is a [[muscle]] at the front of the [[neck]] that consists of two bellies separated by an intermediate [[tendon]]. It belongs to the group of [[infrahyoid muscles]].
==Structure==
It arises from the upper border of the [[scapula]], and occasionally from the [[superior transverse scapular ligament]] which crosses the [[scapular notch]], its extent of attachment to the scapula varying from a few millimetres to 2.5 cm.
From this origin, the ''inferior belly'' forms a flat, narrow [[fasciculus]], which inclines forward and slightly upward across the lower part of the neck, being bound down to the clavicle by a fibrous expansion; it then passes behind the [[sternocleidomastoideus]], becomes tendinous and changes its direction, forming an obtuse angle.
It ends in the ''superior belly'', which passes almost vertically upward, close to the lateral border of the [[sternohyoideus]], to be inserted into the lower border of the body of the [[hyoid bone]], lateral to the insertion of the [[sternohyoideus]].
The central [[tendon]] of this muscle varies much in length and form, and is held in position by a process of the deep cervical fascia, which sheaths it, and is prolonged down to be attached to the [[clavicle]] and first rib; it is by this means that the angular form of the muscle is maintained.
==Triangles==
The inferior belly of the Omohyoideus divides the [[posterior triangle of the neck]] into an upper or [[occipital triangle]] and a lower or [[subclavian triangle]].
Its superior belly divides the [[anterior triangle]] into an upper or [[carotid triangle]] and a lower or [[muscular triangle]].
The Omohyoid muscle is proximally attached to the [[scapula]] and distally attached to the [[hyoid bone]].
==Variations==
Doubling; absence; origin from clavicle; absence or doubling of either belly.
==Innervation==
The omohyoid is innervated by a branch of the [[cervical plexus]], and mostly acts to stabilise the hyoid bone.
==Additional images==
<gallery>
Image:Gray186.png|Hyoid bone. Anterior surface. Enlarged.
Image:Gray203.png|Left scapula. Dorsal surface.
Image:Gray384.png|Section of the neck at about the level of the sixth cervical vertebra. Showing the arrangement of the fascia coli.
Image:Gray385.png|Muscles of the neck. Lateral view.
Image:Gray507.png|Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries.
Image:Gray558.png|The veins of the neck, viewed from in front.
Image:Gray794.png|Hypoglossal nerve, cervical plexus, and their branches.
Image:Gray808.png|The right brachial plexus with its short branches, viewed from in front.
Image:Musculi colli omohyoideus.svg|Musculi colli omohyoideus
</gallery>
The omohyoid muscle is innervated by the ansa cervicalis from the cervical plexus (C1-3)
==External links==
* {{GPnotebook|-1335164848}}
* {{SUNYAnatomyLabs|24|06|01|00}}
* {{SUNYAnatomyFigs|24|01|09}}
* {{MuscleLoyola|omo}}
* {{NormanAnatomy|lesson6}}
{{Gray's}}
{{Muscles of neck}}
[[Category:Muscles of the head and neck]]
{{muscle-stub}}
[[de:Musculus omohyoideus]]
[[es:Omohioideo]]
[[hr:Ramenopodjezični mišić]]
[[ja:肩甲舌骨筋]]
[[pl:Mięsień łopatkowo-gnykowy]]
[[sr:Омохиоидни мишић]]