Muscle
Posterior cricoarytenoid
The muscle that opens each vocal fold
High-yield
Posterior cricoarytenoid is the only intrinsic laryngeal muscle whose principal action is direct vocal-fold abduction. Recurrent nerve injury can weaken both abductors and adductors.
Overview
From the back of the cricoid, fibers converge on the arytenoid's muscular process. Their pull moves the vocal process laterally through combined joint movements. This widens the glottic airway during inspiration.
Reference facts
- Origin
- Posterior surface of the cricoid lamina.
- Insertion
- Muscular process of the arytenoid on the same side.
- Innervation
- Recurrent laryngeal branch of the vagus, continuing as the inferior laryngeal nerve.
- Action
- Moves the vocal process outward and enlarges the rima glottidis.
- Blood supply
- Laryngeal arterial network, including inferior laryngeal branches and connections with the superior supply.
Mnemonic
Picture a pull from behind the cricoid opening the airway.
Clinical correlation
Bilateral vocal-fold paralysis can cause severe stridor when the folds remain close together. Position and severity vary with the lesion and subsequent nerve recovery; permanent midline fixation is not inevitable. Unilateral injury more often affects voice and glottic closure.
Frequently asked questions
What does the posterior cricoarytenoid do?
The posterior cricoarytenoid moves the vocal process outward and enlarges the rima glottidis.
What nerve innervates the posterior cricoarytenoid?
The posterior cricoarytenoid is innervated by the recurrent laryngeal branch of the vagus, continuing as the inferior laryngeal nerve.
Where does the posterior cricoarytenoid attach?
Origin: Posterior surface of the cricoid lamina. Insertion: Muscular process of the arytenoid on the same side.
What is the blood supply of the posterior cricoarytenoid?
The posterior cricoarytenoid is supplied by the laryngeal arterial network, including inferior laryngeal branches and connections with the superior supply.