Interarytenoids

Interarytenoids, or interarytenoid muscles, are intrinsic muscles of the larynx positioned on the posterior aspect of the larynx between the arytenoid cartilages. They comprise two muscles: the transverse interarytenoid and the oblique interarytenoid. The transverse interarytenoid runs horizontally between the posterior surfaces of the arytenoid cartilages, while the oblique interarytenoid extends from the base of one arytenoid to the apex of the opposite arytenoid, forming an oblique, crossing arrangement.

Their primary function is to adduct the vocal folds by approximating the arytenoid cartilages, thereby closing the posterior part of the glottis. This action supports phonation and also plays a role in protective reflexes during coughing and swallowing.

Innervation is provided by the inferior laryngeal nerve, a continuation of the recurrent laryngeal nerve, a branch of the vagus nerve. The muscles receive blood supply from laryngeal branches of the superior and inferior thyroid arteries.

Interarytenoids are part of the intrinsic laryngeal muscle group and work in concert with other muscles that move the vocal folds, such as the posterior cricoarytenoid (which abducts the vocal folds) and the cricothyroid (which tensions the vocal cords). Lesions affecting the recurrent laryngeal nerve can impair interarytenoid function, leading to reduced glottal closure, hoarseness, or aspiration risk.