Which muscle is responsible for adducting the vocal processes of the arytenoids?

The lateral cricoarytenoid muscle is primarily responsible for adducting the vocal processes of the arytenoid cartilages. When this muscle contracts, it rotates the arytenoids inward, bringing the vocal folds together and thus closing the glottis. This action is essential for phonation as it allows for the production of sound by enabling the vibration of the vocal folds when air is passed through them.

In contrast, other muscles mentioned in the choices have different functions. For example, the posterior cricoarytenoid is the only muscle that abducts the vocal folds, pulling the arytenoids apart to open the airway. The oblique arytenoid muscle assists in adducting the vocal folds as well, but its primary role is in bringing the arytenoids closer together in a more oblique manner, which contributes to closure but is not as direct as the lateral cricoarytenoid's action. The cricothyroid muscle primarily functions to adjust the tension of the vocal folds to modulate pitch and does not play a significant role in adduction. Therefore, the choice of the lateral cricoarytenoid accurately identifies the muscle that is responsible for the specific action of adducting the vocal processes of the ary