(pos-tēr'ē-ŏr krī'kō-ar-i-tē'noyd mŭs'ĕl) Intrinsic muscle of larynx; origin, depression on posterior surface of lamina of cricoid; insertion, muscular process of arytenoid; action, abducts vocal folds, widening rima glottidis during deep inhalation; nerve supply, recurrent laryngeal. Synonym(s): musculus cricoarytenoideus posterior.