Final answer:
The epiglottis is the muscle that closes the larynx during swallowing. It works with the infrahyoid and suprahyoid muscles to lift the larynx and prevent aspiration.
Step-by-step explanation:
The muscle that closes the larynx during swallowing is the epiglottis. This flexible piece of elastic cartilage is connected to the thyroid cartilage and functions as a lid over the opening to the trachea. When swallowing, the larynx is pulled upwards and the epiglottis folds downward to cover the glottis. This action prevents food and beverages from entering the trachea, facilitating their proper passage through the esophagus. The laryngeal elevation is aided by the infrahyoid and suprahyoid muscles, which work to control the position and upward movement of the hyoid bone and the larynx.