Head and neck muscles (chewing, facial, and throat muscles)
Posterior cricoarytenoid
Musculus cricoarytenoideus posterior
- Origin
- Posterior surface (lamina) of the cricoid cartilage
- Insertion
- Muscular process of the arytenoid cartilage
- Function
- The only abductor of the vocal folds: rotates the arytenoid cartilage so the vocal process moves laterally and the rima glottidis opens, essential for breathing
- Innervation
- Recurrent laryngeal nerve (branch of the vagus nerve, CN X)
- Movement & chain
- The sole abductor of the vocal folds; acts antagonistically to the adductors (lateral cricoarytenoid, interarytenoid) during breathing and phonation.
- Palpation
- Not palpable; situated on the posterior lamina of the cricoid cartilage.
- Clinical
- Bilateral paralysis (for example after thyroid surgery damaging both recurrent laryngeal nerves) causes life-threatening airway obstruction because the vocal folds can no longer be abducted.
- Segmental innervation
- Motor via the nucleus ambiguus, vagus nerve (X); no spinal segment.
- In clinical practice
- The SOLE abductor of the vocal folds (opens the glottis); bilateral recurrent laryngeal nerve injury causes acute stridor and life-threatening airway obstruction requiring emergency tracheostomy.
- Region in the model
- Head and neck muscles (chewing, facial, and throat muscles)