The Posterior Cricoarytenoid Muscle Is Essential for Airway Patency Through the Larynx
The posterior cricoarytenoid muscle is the primary and only muscle responsible for abducting the vocal folds, which is essential for allowing air movement through the larynx. 1
Anatomical and Functional Importance
The posterior cricoarytenoid (PCA) muscle plays a critical role in respiratory function by:
- Acting as the sole abductor of the vocal folds, opening the glottic airway during inspiration 1
- Working in coordination with the cricothyroid muscle to accentuate laryngeal opening 1
- Creating the necessary glottic width required for adequate airflow during breathing 2
During respiration, particularly during increased ventilatory demands, the PCA demonstrates increased electromyographic activity that directly correlates with widening of the vocal cords in both inspiratory and expiratory phases of the respiratory cycle 2.
Functional Anatomy
The PCA muscle functions within the cricoarytenoid articulation, which has three degrees of freedom during vocal fold movement:
- Anteroposterior rocking movement
- Anteromedial shift of the arytenoid on the cricoid
- Axial rotation (less pronounced) 3
This complex joint mobility allows the PCA to effectively pull the arytenoid cartilages posteriorly and laterally, thereby abducting the vocal folds and opening the airway.
Clinical Significance
The critical importance of the PCA muscle is evident in pathological conditions:
- Bilateral vocal fold paralysis affecting the PCA muscles can lead to severe airway compromise requiring tracheostomy 4
- Damage to the recurrent laryngeal nerve (RLN), which innervates the PCA, is a serious complication of thyroid surgery that can result in vocal fold immobility 5
- The RLN carries motor fibers to all intrinsic laryngeal muscles except the cricothyroid, with the PCA being the only abductor among these muscles 5
Implications of PCA Dysfunction
When PCA function is compromised:
- Patients may experience dyspnea, especially during physical activity 4
- Bilateral PCA paralysis can cause life-threatening airway obstruction 4
- Surgical reinnervation of the PCA muscles may be necessary to restore inspiratory vocal fold abduction 4
Diagnostic Considerations
Laryngeal electromyography (LEMG) can be used to assess PCA function and diagnose vocal fold paresis or paralysis 5. This is particularly important in cases where visual examination alone may not reveal the underlying neurological dysfunction.
Understanding the crucial role of the posterior cricoarytenoid muscle in maintaining airway patency is essential for proper diagnosis and management of laryngeal disorders that affect breathing and voice production.