The Mechanics of the Cricoarytenoid Joint

The mechanics of the cricoarytenoid joint control abduction and adduction of the vocal cords, and thereby facilitate respiration, protect the airway, and permit phonation and other functions of the larynx. Unfortunately, the obscure position of this joint and its complex structure have led to several misconceptions of arytenoid motion in current textbooks. The common monocular inspection of the larynx, for instance, leads the observer to the conclusion that the motions of the cricoarytenoid joint may be based on a vertical axis of rotation, or on a linear lateral glide. Recent anatomic, cinematographic, and mathematical studies necessitate a revision of this traditional concept. Anatomic dissections readily establish a shallow elongated ball-and-socket joint on the lateral aspect of the cricoid rim; the location and configuration countermand the customary description of arytenoid motion. The structural arrangement of the cricoarytenoid joint permits 2 principal types of motion: (1) a rocking or rotating movement around