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

The musculus arytenoideus transversus is the only unpaired intrinsic muscle of the larynx and runs horizontally between the cartilagines arytenoideae. The musculus arytenoid obliquus is a paired muscle and originates from the processus muscularis of the cartilago arytenoidea. It extends obliquely towards its superiorly located insertion on the contralateral cartilago arytenoidea. Along its path, the musculus arytenoid obliquus crosses its counterpart from the opposite side, forming the letter ‘X’. Upon contraction, the musculus arytenoideus transversus and obliquus 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).