The thyroarytenoid muscle is a broad, thin muscle that forms the body of the

vocal fold In humans, the vocal cords, also known as vocal folds, are folds of throat tissues that are key in creating sounds through Speech, vocalization. The length of the vocal cords affects the pitch of voice, similar to a violin string. Open when brea ...

and that supports the wall of the ventricle and its appendix. It functions to shorten the vocal folds.

Structure

It arises in front from the lower half of the angle of the thyroid cartilage, and from the middle cricothyroid ligament. Its fibers pass backward and laterally, to be inserted into the base and anterior surface of the

arytenoid cartilage The arytenoid cartilages () are a pair of small three-sided pyramids which form part of the larynx. They are the site of attachment of the vocal cords. Each is pyramidal or ladle-shaped and has three surfaces, a base, and an apex. The arytenoid ...

Parts

The lower and deeper fibers of the muscle can be differentiated as a triangular band which is inserted into the vocal process of the arytenoid cartilage, and into the adjacent portion of its anterior surface; it is termed the ''Vocalis'', and lies parallel with the

vocal ligament In humans, the vocal cords, also known as vocal folds, are folds of throat tissues that are key in creating sounds through vocalization. The length of the vocal cords affects the pitch of voice, similar to a violin string. Open when breathing a ...

, to which it is adherent.Frank H. Netter, MD "Atlas of Human anatomy", 7th Edition, 2019, Plate 91, superior view The vocal muscle is the upper portion of the thyroarytenoid muscle which is primarily involved in producing speech. A considerable number of the fibers of the thyroarytenoid muscle are prolonged into the

aryepiglottic fold The aryepiglottic folds are triangular folds of mucous membrane of the larynx. They enclose ligamentous and muscular fibres. They extend from the lateral borders of the epiglottis to the arytenoid cartilages, hence the name 'aryepiglottic'. The ...

, where some of them become lost, while others are continued to the margin of the epiglottis. They have received a distinctive name,

thyroepiglottic muscle A considerable number of the fibers of the thyroarytenoid muscle are prolonged into the aryepiglottic fold, where some of them become lost, while others continue to the margin of the epiglottis. They have received a distinctive name, thyroepiglot ...

, ''thyreoepiglotticus'' or ''thyroepiglottic'', and are sometimes described as a separate muscle. A few fibers extend along the wall of the ventricle from the lateral wall of the arytenoid cartilage to the side of the epiglottis and constitute the ''ventricularis'' muscle.

Function

The thyroarytenoid muscle, consisting of two parts having different attachments and different directions, is rather complicated regarding its action. Its main use is to draw the arytenoid cartilages forward toward the thyroid, thus relaxing and shortening the vocal folds. But, owing to the connection of the deeper portion with the vocal fold, this part, if acting separately, is supposed to modify its elasticity and tension, while the lateral portion rotates the arytenoid cartilage inward, and thus narrows the

rima glottidis The rima glottidis is the opening between the two true vocal cords anteriorly, and the two arytenoid cartilages posteriorly. It is part of the larynx. Anatomy The rima glottidis is the narrowest part of larynx. It is longer (~23 mm) in ...

by bringing the two vocal folds together.

Additional images

File:Gray959.png, Muscles of larynx. Side view. Right lamina of thyroid cartilage removed. File:Vocalis muscle.JPG, Cross sectional cut of vocalis muscle

References

External links

* * {{Authority control Muscles of the head and neck