The lateral cricoarytenoid (also anterior cricoarytenoid) muscles extend from the lateral cricoid cartilage to the ipsilateral arytenoid cartilage

Arytenoid cartilage

The arytenoid cartilages are a pair of small three-sided pyramids which form part of the larynx, to which the vocal folds are attached...

. By rotating the arytenoid cartilages medially, these muscles adduct the vocal cords and thereby close the rima glottidis

Rima glottidis

The rima glottidis is the opening between the true vocal cords and the arytenoid cartilages.It is normally subdivided into two parts, that between the arytenoid cartilages is called the intercartilaginous part , and that between the vocal folds the intermembranous part or glottis vocalis.It is...

, protecting the airway. (Their action is antagonistic to that of the posterior cricoarytenoid muscle

Posterior cricoarytenoid muscle

The posterior cricoarytenoid muscles are extremely small, paired muscles that extend from the posterior cricoid cartilage to the arytenoid cartilages in the larynx. By rotating the arytenoid cartilages laterally, these muscles abduct the vocal cords and thereby open the rima glottidis. Their action...

s.) The lateral cricoarytenoid muscles receive innervation from the recurrent laryngeal branch of the vagus nerve

Vagus nerve

The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...

(CN X).