The Muscular System Logo

All Muscles

Search Icon Search Icon

Thyrohyoid

By

Della Barnes, an MS Anatomy graduate, blends medical research with accessible writing, simplifying complex anatomy for a better understanding and appreciation of human anatomy.

Avatar photo Della Barnes, MS Anatomy

Last updated:

02/12/2025
Avatar photo
Della Barnes, MS Anatomy
UX/UI Designer at - Adobe

Della Barnes, an MS Anatomy graduate, blends medical research with accessible writing, simplifying complex anatomy for a better understanding and appreciation of human anatomy.

What is the Thyrohyoid

Thyrohyoid is a small paired muscle located in the neck, below the mandible or lower jaw. It belongs to the group of infrahyoid muscles along with the sternohyoid, sternothyroid, and omohyoid muscles. Being located beneath the hyoid bone, its primary function involves depressing the hyoid bone and helping with swallowing. 

Anatomy

Location and Attachments

OriginOblique line on the lamina of the thyroid cartilage
InsertionGreater horn (cornu) and body of the hyoid bone

Origin

It originates from the oblique line along the lamina of the thyroid cartilage, the same cartilagenous ridge where the sternothyroid muscle ends. Because of this shared attachment site, the thyrohyoid is often regarded as a superior continuation of the sternothyroid.

Insertion

The muscle fibers arise as a thin sheet along the oblique line and ascend vertically, gradually thickening to form the quadrilateral muscle belly. As they approach their insertion, the fibers converge slightly before attaching along the inferior border of the greater horn (cornu) of the hyoid bone and the adjoining portion of the hyoid body.

Relations With Surrounding Muscles and Structures

It lies in the deep layer of the infrahyoid group, enclosed by the pretracheal layer of the deep cervical fascia. The upper part of the sternothyroid muscle, the only other deep infrahyoid muscle, lies superficial to the thyrohyoid’s inferior part. The superior belly of the omohyoid crosses the anterior surface of the muscle.

Superiorly, the muscle is related to the stylohyoid and the posterior belly of the digastric, both of which pass superficial to it. Deep to its upper portion lies the lateral part of the thyrohyoid membrane.

The muscle’s quadrilateral belly contributes to the medial boundary of the carotid triangle, an anterolateral neck region containing several important neurovascular structures. Among these, the superior thyroid artery and vein, which branch off the external carotid system, descend along the lateral side of the thyrohyoid, forming one of its key vascular relationships.

Function

ActionElevating the larynx and depressing the hyoid bone to help with swallowing and vocalization

When the suprahyoid muscles stabilize the hyoid bone, the thyrohyoid, working with the infrahyoid group, helps elevate the larynx (voice box). This upward movement protects the airway during swallowing and also contributes to sound production by positioning the vocal cords.

Following the pharyngeal phase of swallowing, the thyrohyoid helps depress the hyoid bone, returning it to its resting position.

The thyrohyoid muscle is also thought to assist in producing high-pitched notes, although it is not considered a primary muscle for pitch control.

Antagonists

The thyrohyoid muscle has no direct anatomical antagonist. However, as part of the infrahyoid group, its action of depressing the hyoid is functionally opposed by the suprahyoid muscles, mylohyoid, stylohyoid, digastric, and geniohyoid, which elevate the hyoid bone.

Innervation

NerveVentral rami of the C1 nerve, via the hypoglossal nerve

The muscle’s innervation comes from the ventral rami of the first cervical (C1) spinal nerve, via the CN XII, also known as the hypoglossal nerve. Thyrohyoid is the only infrahyoid muscle that does not receive innervation via the ansa cervicalis.

Blood Supply

ArterySuperior laryngeal and infrahyoid branches of the superior thyroid artery

The primary blood supply to the muscle comes from the superior thyroid artery, specifically through its superior laryngeal and infrahyoid branches. Additional supply is provided by the lingual artery. All arteries supplying this muscle originate from the external carotid artery.

References

  1. Thyrohyoid: TeachMeAnatomy.info
  2. Thyrohyoid Muscle: Kenhub.com
  3. Thyrohyoid Muscle:  Elsevier.com
  4. Thyrohyoid: HealthLine.com
  5. Thyrohyoid Muscle: Radiopaedia.org
Avatar photo
Della Barnes, MS AnatomyUX/UI Designer at - Adobe

Della Barnes, an MS Anatomy graduate, blends medical research with accessible writing, simplifying complex anatomy for a better understanding and appreciation of human anatomy.

Leave a comment

Your email address will not be published. Required fields are marked *

5 + 3 =