The intrinsic muscles of the larynx (Table 8.19) adjust tension in the vocal ligaments, open and close the rima glottidis, control the inner dimensions of the vestibule, close the rima vestibuli, and facilitate closing of the laryngeal inlet. They do this mainly by: acting on the cricothyroid and crico-arytenoid joints, adjusting the distance between the epiglottis and arytenoid cartilages, pulling directly on the vocal ligaments, and forcing soft tissues associated with the quadrangular membranes and vestibular ligaments toward the midline.