The oblique arytenoid muscle consists of two fibres that cross over the back of the larynx in an X pattern, each running from the muscular process of one arytenoid to the apex of the opposite. Their superior fibres continue as the aryepiglottic muscle to the margin of the epiglottis. Together with the transverse arytenoid, the oblique arytenoid closes the posterior glottis, and via its aryepiglottic continuation, it narrows the laryngeal inlet during swallowing to protect the airway.
| Origin | Muscular process of one arytenoid cartilage |
|---|---|
| Insertion | Apex of the opposite arytenoid cartilage, continuing as the aryepiglottic muscle to the epiglottis |
| Nerve Supply | Recurrent laryngeal nerve (CN X) |
| Blood Supply | Superior and inferior laryngeal arteries |
| Actions | Adducts the arytenoid cartilages (assists transverse arytenoid); Folds the aryepiglottic folds, narrowing the laryngeal inlet during swallowing (via aryepiglottic continuation) |
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The oblique arytenoid and its aryepiglottic continuation play an essential role in airway protection during swallowing by adducting the arytenoids and tilting the epiglottis posteriorly. Neurological conditions affecting the recurrent laryngeal nerve bilaterally (motor neurone disease, brainstem stroke, bilateral RLN palsy) impair these muscles and cause silent aspiration. In omega-shaped epiglottis (a variant of supraglottic anatomy), the aryepiglottic folds are prominent and sometimes surgically reduced.
Not directly palpable; assessed by laryngoscopy.
Bilateral weakness of the oblique arytenoid and aryepiglottic muscles in neurological disease reduces laryngeal inlet closure during swallowing, allowing silent aspiration of liquids that is detected by flexible endoscopic evaluation of swallowing (FEES) and managed with thickened fluids and swallowing rehabilitation.
