Geniohyoid muscle

The geniohyoid muscle is a narrow paired 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")^[1] to the hyoid bone.

Geniohyoid muscle
Anterior view. Geniohyoid muscle labeled at upper center left
Extrinsic muscles of the tongue. Left side.
Details
Origin	Inferior mental spine of mandible
Insertion	Hyoid bone
Artery	Branches of the lingual artery.
Nerve	C1 via the hypoglossal nerve
Actions	Carry hyoid bone and the tongue upward during deglutition
Identifiers
Latin	musculus geniohyoideus
TA98	A04.2.03.007
TA2	2166
FMA	46325
Anatomical terms of muscle [edit on Wikidata]

Structure

The geniohyoid is a paired short muscle that 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.^[2]: 346 It lies in contact with its fellow of the opposite side. It thus belongs to the suprahyoid muscles. The muscle receives its blood supply from branches of the lingual artery.^[3]

Innervation

The geniohyoid muscle is innervated by fibres from the first cervical spinal nerve travelling alongside the hypoglossal nerve.^[2][4][5] Although the first three cervical nerves give rise to the ansa cervicalis, the geniohyoid muscle is said to be innervated by the first cervical nerve, as some of its efferent fibers do not contribute to ansa cervicalis.^{[clarification needed]}

Variations

It may be blended with the one on opposite side or double; slips to greater cornu of hyoid bone and genioglossus occur.^{[citation needed]}

Function

The geniohyoid muscle brings the hyoid bone forward and upwards.^[2] This dilates the upper airway, assisting respiration.^[4] 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.^[3]

History

The inclined position of the geniohyoid muscle has been contrasted to the horizontal position in neanderthals.^[6]

Additional images

• 
  Illustration of the hyoid bone showing the insertion point of the geniohyoid muscle
• 
  Sagittal section of nose mouth, pharynx, and larynx.
• 
  Geniohyoid muscle
• 
  Geniohyoid muscle
• 
  Geniohyoid muscle

See also

This article uses anatomical terminology.