USING JOINT GEOMETRY TO DETERMINE THE MOTION OF THE CRICOARYTENOID JOINT

Facet surfaces of the cricoarytenoid joints from two cadaver larynges were digitized. The data were used to compute the optimal axis of rota tion for each of the joints in the sense that the computed axis minimi zed the variance of the joint gap over the full range of joint motion. The optimal axis corresponded to a rocking motion of the arytenoid on the corresponding cricoid. This motion was consistent with experiment al data from digitized recordings of vocal fold movement. Using the ri gid laryngoscopic view, a similarity in vocal process movement, over t he range in motion, between the rocking axis and the vertical axis des cribed in the literature was found, resolving the controversy between two conflicting views of motion of the vocal processes. (C) 1998 Acous tical Society of America. [S0001-4966(98)04902-9].