|Side of neck, showing chief surface markings. (Omohyoideus visible at center.)|
|Muscles of the neck. Anterior view. Omohyoid is labeled on both sides.|
|Gray's||subject #112 392|
|Origin:||Upper border of the scapula|
|Action:||Depresses the larynx and hyoid bone. Also carries hyoid bone backward and to the side.|
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.
Doubling; absence; origin from clavicle; absence or doubling of either belly.
The omohyoid is innervated by a branch of the cervical plexus, and mostly acts to stabilise the hyoid bone.
The omohyoid muscle is innervated by the ansa cervicalis from the cervical plexus (C1-3)
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