The posterior cricoarytenoid is the only muscle that opens the vocal folds, making it the most critical of all laryngeal muscles for airway patency. Bilateral PCA paralysis causes stridor and potentially fatal airway obstruction.
| Origin | Posterior surface of the cricoid lamina |
|---|---|
| Insertion | Muscular process of the arytenoid cartilage |
| Nerve Supply | Recurrent laryngeal nerve (CN X) |
| Blood Supply | Laryngeal branch of inferior thyroid artery |
| Actions | Abducts the vocal folds — the ONLY laryngeal abductor; Opens the glottis for breathing; Critical for airway patency during inspiration |
|---|
Bilateral PCA palsy from bilateral RLN injury (rare, but occurring in re-operative thyroid surgery or central neck dissection) produces acute airway obstruction requiring emergency tracheostomy. Unilateral PCA palsy from RLN injury produces the classic vocal fold paralysis in the paramedian position. Posterior cordotomy or arytenoidectomy widens the airway by destroying the adductor structures.
Not palpable externally — assessed by laryngoscopy showing vocal fold abduction on inspiration.
Bilateral recurrent laryngeal nerve injury denervating both posterior cricoarytenoid muscles producing acute bilateral vocal fold adduction and airway obstruction, requiring emergency tracheostomy.
