Larynx: action of transverse and oblique arytenoid muscles (English)

The transverse arytenoid muscle is the only unpaired intrinsic muscle of the larynx and runs horizontally between the arytenoid cartilages. The oblique arytenoid muscle is a paired muscle and originates from the muscular process of the arytenoid cartilage. It extends obliquely towards its superiorly located insertion on the contralateral arytenoid cartilage. Along its path, the oblique arytenoid muscle crosses its counterpart from the opposite side, forming the letter “X”. Upon contraction, the transverse and oblique arytenoid muscles adduct the vocal folds, closing the posterior portion of the rima glottidis and narrow the aditus laryngis. The closed/slit-like appearance of the rima glottidis in this image represents that seen during phonation (production of speech sounds).