Musculus cricoarytaenoideus posterior, also known as the posterior cricoarytenoid muscle, is a paired muscle located in the posterior part of the larynx, or voice box. This muscle plays a vital role in the opening and closing of the vocal folds and is responsible for controlling the tension and movement of the vocal cords.
The posterior cricoarytenoid muscle originates from the posterior surface of the cricoid cartilage, which is a ring-shaped structure located just below the thyroid cartilage in the larynx. From there, it inserts into the muscular process of the arytenoid cartilage, which is another small cartilaginous structure within the larynx.
The main function of the musculus cricoarytaenoideus posterior is to abduct the vocal folds. This means that it pulls the vocal cords apart, opening up the glottis and allowing air to flow freely through the larynx during inhalation. This action is crucial for the production of sound and speech.
Additionally, the musculus cricoarytaenoideus posterior is the only muscle in the larynx that is capable of actively and directly opening the vocal folds. It also plays a crucial role in protecting the airway during certain reflex actions, such as coughing and sneezing.
Overall, the musculus cricoarytaenoideus posterior is a key muscle in the larynx that controls the movement and tension of the vocal folds, facilitating the process of breathing, sound production, and protecting the airway.
