Oblique arytenoid muscle

The oblique arytenoid muscles are paired intrinsic muscles of the larynx that play a key role in closing the laryngeal inlet during swallowing.

Origin and Insertion

Each oblique arytenoid muscle originates from the muscular process of one arytenoid cartilage and ascends obliquely across the posterior surface of the larynx to insert into the apex of the opposite arytenoid cartilage. The fibres of the right and left muscles cross each other in the midline, forming an X-shaped pattern over the posterior surface of the transverse arytenoid muscle.

Action

Contraction of the oblique arytenoids adducts the arytenoid cartilages, thereby closing the posterior part of the rima glottidis and narrowing the laryngeal inlet. The oblique arytenoids together with the transverse arytenoid and the thyroarytenoid work as a sphincter and close the larynx as we swallow or cough, preventing aspiration of food or fluid into the airway.

Innervation

Both muscles are supplied by the recurrent laryngeal nerve, a branch of the vagus nerve (cranial nerve X).

Aryepiglottic part of oblique arytenoids

A fibres of the oblique arytenoids continue upward into the aryepiglottic fold to insert into the lateral margin of the epiglottis, acting to narrow the laryngeal inlet during swallowing. This is referred to as the aryepiglottic part of oblique arytenoid muscle (a.k.a. the Aryepiglotticus).