Thyrohyoid

General information

Thyrohyoid is a small, quadrilateral muscle located in the neck’s anterior triangle. It belongs to a group of muscles known as the infrahyoid muscles. There are four infrahyoid muscles in total - the others being the sternohyoid, sternothyroid and omohyoid.

Literal meaning

Shield shape or form.

Interesting information

The Infrahyoid muscles are divided into superficial and deep layers, with the thyrohyoid situated in the deeper layer alongside the sternothyroid, while the others are situated in the superficial layer.

This muscle has two main actions: to depress the hyoid bone with the other muscles in the group, which is necessary after the swallowing action and also to elevate the larynx when the hyoid bone has been stabilised. This is significant for singers who need to reach high notes.

Origin

Oblique line of thyroid cartilage.

Insertion

Inferior border of body and greater horn of hyoid bone.

Function

Depresses hyoid bone.

Elevates larynx.

Nerve supply

Anterior ramus of spinal nerve C1 via hypoglossal nerve (CN XII).

Blood supply

Branches of lingual and superior thyroid arteries.

Relevant research

The objective of the study was to review clinical results for the thyrohyoid approach for an in-office vocal fold augmentation and calcium hydroxyapatite. The charts for everyone who underwent the procedure from June 1, 2005 through June 1, 2007 were analysed. Information was collecting regarding the demographics, complications, indications and outcome of the patients.

51 different procedures were performed on 33 patients, of which 26 were men with an average age of 66. Six procedures ended up being aborted due to the inability to achieve the appropriate angle for injection. Two self-limited complications resulted in a small ulcer located near the petiole of the epiglottis and a vasovagal episode. 62.5% of the cases had pre- and post-procedure data available. Average voice index improved from 27.9 to 13.5 after the procedure. The study authors concluded that in-office vocal fold augmentation using the thyrohyoid approach gives excellent clinical results, with few complications, and is their technique of choice.

Rees CJ, Mouadeb DA, Belafsky PC. Thyrohyoid vocal fold augmentation with calcium hydroxyapatite. Otolaryngol Head Neck Surg. 2008;138(6):743-746. doi:10.1016/j.otohns.2008.02.023

Thyrohyoid exercises

Neck flexion

Sit in a chair and move the head back to the point where the face is looking at the ceiling. Place the hands behind the head and use them as a means of building resistance. Perform this movement 10 times.