Larynx: action of posterior cricoarytenoid muscle (English)

The proximal attachment of posterior cricoarytenoid muscle is on the posterior surface of the cricoid cartilage and its corresponding insertion point is on the muscular process of the arytenoid cartilage. Contraction of the posterior cricoarytenoid muscle rotates the arytenoid cartilages laterally and pulls them posterolaterally. Therefore, it is the only muscle of the larynx that abducts the vocal cords and opens the rima glottidis. This action makes the posterior cricoarytenoid muscle the most important muscle in the larynx in the act of respiration. The open appearance of the rima glottidis in this image represents that seen during forced respiration.