Ultrastructure of the vocal process of the arytenoid cartilage.

An investigation of the ultrastructure of the vocal process of the arytenoid cartilage was performed on excised human adult larynges. The results are summarized as follows. 1) The size of the chondrocytes is small and their density is high at the tip of the vocal process. 2) The size of the chondrocytes increases and their density decreases toward the posterior portion of the vocal process. 3) At the tip of the vocal process, the collagenous fibers are thin and run in various directions. 4) The thickness of the collagenous fibers increases and they form thick bundles toward the posterior portion of the vocal process. 5) The elastic fibers are dense at the tip of the vocal process, and their number decreases toward the posterior portion of the vocal process. 6) The elastic fibers, which are slender, branched, and anastomosed to form a loose network, run among the collagenous fibers at the tip of the vocal process. 7) Elaunin fibers are the predominant elastic fibers at the tip of the vocal process. 8) Even in the hyaline cartilage portion of the vocal process, elastic fibers are found. 9) The vocal processes are firm in forming the framework of the glottis and are more pliable toward the tip. 10) The 3-dimensional structure of the gradual changes in stiffness between the vocal fold and the vocal process makes a functional contribution to the roles of the vocal folds and the vocal processes.