Closure of the laryngeal vestibule during deglutition.

With the aid of high-speed cineradiography (up to 100 frames per second) the closure of the laryngeal vestibule during deglutition was studied in 150 volunteers free from swallowing complaints. The closure was observed to be effected by a peristaltic-like wave from below. This was accomplished in two steps. First the caudal segment of the vestibule, the supraglottic space, was closed by an apposition of the side walls. Then the cranial segment of the vestibule, the supraglottic space, was closed by an apposition of the fixed part of the epiglottis to the arytenoid region. The subdivision of the vestibule was made by an imaginary plane between the interarytenoid incisure and incisure of the thyroid cartilage. This subdivision corresponds to the location of the thyroarytenoid muscles lateral to the supraglottic space and the thyroepiglottic muscles lateral to the subepiglottic space. In this way the two muscle pairs contribute indifferent and distinct ways to the closure of the vestibule during deglutition.