Larynx: action of vocalis and thryoarytenoid muscles (English)

The thyroarytenoid muscle is a wide, paired muscle arising from the inner surface of thyroid cartilage, near the midline, as well as the cricothyroid ligament. Its fibers pass posterolaterally to insert into the anterolateral surface of the arytenoid cartilage. The vocalis muscle is a small, paired strand-like muscle which sits parallel to the vocal ligament. It originates at the lateral surface of the vocal process of arytenoid cartilage, runs anteromedially across the laryngeal inlet and attaches to the anterior part of the ipsilateral vocal ligament near the thyroid cartilage. The thyroarytenoid and vocalis muscles both draw the arytenoid cartilages anteriorly allowing the vocal ligaments to shorten, thicken and relax. This means they play a crucial part in controlling and changing the tonal quality of the voice. Concurrently, both muscles rotate the arytenoid cartilages medially which helps in closing the rima glottidis. The narrow/wedge-shaped appearance of the rima glottidis in this image represents that seen during normal respirations (‘resting’ position).