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Posterior Cricoarytenoid Detail

musculus cricoarytenoideus posterior detail

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.

Nerve: Recurrent laryngeal nerve (CN X) Blood Supply: Laryngeal branch of inferior thyroid artery Region: Head & Skull

Anatomical Data

Origin, Insertion & Supply

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

Biomechanics

Function & Actions

Actions	Abducts the vocal folds — the ONLY laryngeal abductor; Opens the glottis for breathing; Critical for airway patency during inspiration

Clinical Relevance

Clinical Notes

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.

Palpation

Not palpable externally — assessed by laryngoscopy showing vocal fold abduction on inspiration.

Pathology

Common Injuries & Conditions

Bilateral PCA Paralysis — Airway Emergency

Bilateral recurrent laryngeal nerve injury denervating both posterior cricoarytenoid muscles producing acute bilateral vocal fold adduction and airway obstruction, requiring emergency tracheostomy.