The thyrohyoid muscle is a small

skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...

of the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

. Above, it attaches onto the

greater cornu The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verteb ...

of the

hyoid bone The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ...

; below, it attaches onto the oblique line of the thyroid cartilage. It is innervated by fibres derived from the cervical spinal nerve 1 that run with the hypoglossal nerve (CN XII) to reach this muscle. The thyrohyoid muscle depresses the

and elevates the

larynx The larynx (), commonly called the voice box, is an organ (anatomy), organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal ...

during swallowing. By controlling the position and shape of the larynx, it aids in making sound.

Structure

The thyrohyoid muscle is a small, broad and short muscle. It is

quadrilateral In Euclidean geometry, geometry a quadrilateral is a four-sided polygon, having four Edge (geometry), edges (sides) and four Vertex (geometry), corners (vertices). The word is derived from the Latin words ''quadri'', a variant of four, and ''l ...

in shape. It may be considered a superior-ward continuation of sternothyroid muscle. It belongs to the infrahyoid muscles group and the outer laryngeal muscle group.

Attachments

Its superior attachment is the inferior border of the

of the

and adjacent portions of the

body of hyoid bone The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ...

. Its inferior attachment is the oblique line of the thyroid cartilage (alongside the sternothyroid muscle).

Innervation

The thyrohyoid muscle is innervated (along with the

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") to the hyoid bone. Structure The geniohyoid is ...

) by a branch of the

cervical plexus The cervical plexus is a nerve plexus of the anterior rami of the first (i.e. upper-most) four cervical spinal nerves C1-C4. The cervical plexus provides motor innervation to some muscles of the neck, and the diaphragm; it provides sensory inne ...

- the nerve to thyrohyoid muscle (thyrohyoid branch of ansa cervicalis) - which is formed by fibres of the cervical spinal nerve 1 (C1) (and - according to some sources -

cervical spinal nerve 2 The cervical spinal nerve 2 (C2) is a spinal nerve of the cervical segment.American Medical Association

as well) that join and travel with the hypoglossal nerve (CN XII) before splitting away from it distal to the superior root of ansa cervicalis. The thyrohyoid muscle is the only infrahyoid muscle that is not innervated via the

ansa cervicalis The ansa cervicalis (or ansa hypoglossi in older literature) is a loop formed by muscular branches of the cervical plexus formed by branches of cervical spinal nerves C1-C3. The ansa cervicalis has two roots - a superior root (formed by branch o ...

Blood supply

The muscle is provided with arterial blood by branches of the

superior thyroid artery The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland. Structure From its origin under the anterior border of the sternocleidomastoid the super ...

, and of the lingual artery.

Relations

The thyrohyoid muscle forms the inferior boundary of the carotid triangle. It is situated deep to (beneath) the (depending upon the source) superior portion of/superior belly of the

sternohyoid muscle The sternohyoid muscle is a bilaterally paired, long, thin, narrow strap muscle of the anterior neck. It is one of the infrahyoid muscles. It is innervated by the ansa cervicalis. It acts to depress the hyoid bone. The sternohyoid muscle is ...

, and the superior portion of the omohyoid muscle.

Function

The thyrohyoid muscle depresses and fixates the

. It elevates the

during swallowing. By controlling the position and shape of the larynx, it aids in making sound.

Additional images

File:Gray186.png, Hyoid bone. Anterior surface. Enlarged. File:Gray560.png, The veins of the thyroid gland. File:Gray794.png, Hypoglossal nerve, cervical plexus, and their branches. File:Gray808.png, The right brachial plexus with its short branches, viewed from in front. File:Gray957.png, Side view of the larynx, showing muscular attachments. File:Slide8e.JPG, Thyrohyoid muscle

Notes

References

External links

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PTCentral
{{Authority control Muscles of the head and neck

Structure

Attachments

Innervation

Blood supply

Relations

Function

Additional images

See also

Notes

References

External links