Abstract
The structure of the crico-arytenoid joint was demonstrated by computer graphics of the human larynx reconstructed from serial cross sections. The cricoid facet was more or less oval, and its sagittal cross section could be approximated to part of a circle. In frontal cross sections of the cricoid facet, the medial part was more sharply curved than the lateral part. At the anterior part of the facet, these curvature radii became similar.
Computer simulation of the movement of the arytenoid cartilage was then performed. Simulation of the sliding motion of the arytenoid cartilage showed the vocal process to move less in the antero-posterior direction than in the other direction. Simulation of the rocking motion of the arytenoid cartilage showed the arytenoid cartilage to move more widely at the median position than at the anteriorly- or posteriorly-sliding position. The movement of the vocal process was greatest at this median position.
It will be necessary to identify the direction of the internal laryngeal muscle fibers by examination of the reconstructed larynx. Then it will be possible to simulate the relationship between the condition of the laryngeal muscles and the glottal shape.
