Insertion Hyoid bone | Latin Musculus geniohyoideus | |
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Origin Inferior mental spine of mandible Artery Branches of the lingual artery. Nerve C1 via the hypoglossal nerve Actions Carry hyoid bone and the tongue upward during deglutition | ||
The geniohyoid muscle is a narrow muscle situated superior to the medial border of the mylohyoid muscle. It is named for its passage from the chin ("genio-" is a standard prefix for "chin") to the hyoid bone.
Contents
Structure
It arises from the inferior mental spine, on the back of the mandibular symphysis, and runs backward and slightly downward, to be inserted into the anterior surface of the body of the hyoid bone. It lies in contact with its fellow of the opposite side. It thus belongs to the suprahyoid muscles. The muscle is supplied by branches of the lingual artery.
Innervation
The geniohyoid muscle is innervated by fibres from the first cervical nerve travelling alongside the hypoglossal nerve. These fibers are called ansa cervicalis.
Variations
It may be blended with the one on opposite side or double; slips to greater cornu of hyoid bone and Genioglossus occur.
Function
The geniohyoid muscle brings the hyoid bone forward and upwards. This dilates the upper airway, assisting respiration. During the first act of deglutition, when the mass of food is being driven from the mouth into the pharynx, the hyoid bone, and with it the tongue, is carried upward and forward by the anterior bellies of the Digastrici, the Mylohyoidei, and Geniohyoidei. It also assists in depressing the mandible
History
The inclined position of the geniohyoid muscle has been contrasted to the horizontal position in neanderthals.