Larynx: action of posterior cricoarytenoid muscle (Latin)

The proximal attachment of musculus cricoarytenoid posterior is on the posterior surface of the cartilago cricoidea and its corresponding insertion point is on the processus muscularis of the cartilago arytenoidea. Contraction of the musculus cricoarytenoid posterior rotates the cartilagines arytenoideae laterally and pulls them posterolaterally. Therefore, it is the only muscle of the larynx that abducts the plicae vocales and opens the rima glottidis. This action makes the musculus cricoarytenoid posterior 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.