The posterior cricoarytenoids (Figures 5-8) originate on the posterior surface of the cricoid cartilage and insert into the muscular process of each arytenoid cartilage. Their action (cf.Fig.6) is to pivot the arytenoids, separating their opposing vocal processes and thus abducting the vocal cords or in other words, opening the glottis. This set of muscles would be involved in the production of all voiceless pulmonic phones.