Interaction Between the Thyroarytenoid and Lateral Cricoarytenoid Jun Yin1 Muscles in the Control Speech Production Laboratory, Department of Head and Neck Surgery, of Vocal Fold Adduction University of California, Los Angeles, 31-24 Rehabilitation Center, 1000 Veteran Avenue, and Eigenfrequencies Los Angeles, CA 90095-1794 2 Although it is known vocal fold adduction is achieved through laryngeal muscle activa- Zhaoyan Zhang tion, it is still unclear how interaction between individual laryngeal muscle activations Speech Production Laboratory, affects vocal fold adduction and vocal fold stiffness, both of which are important factors Department of Head and Neck Surgery, determining vocal fold vibration and the resulting voice quality. In this study, a three- University of California, Los Angeles, dimensional (3D) finite element model was developed to investigate vocal fold adduction 31-24 Rehabilitation Center, and changes in vocal fold eigenfrequencies due to the interaction between the lateral cri- 1000 Veteran Avenue, coarytenoid (LCA) and thyroarytenoid (TA) muscles. The results showed that LCA con- Los Angeles, CA 90095-1794 traction led to a medial and downward rocking motion of the arytenoid cartilage in the e-mail:
[email protected] coronal plane about the long axis of the cricoid cartilage facet, which adducted the pos- terior portion of the glottis but had little influence on vocal fold eigenfrequencies. In con- trast, TA activation caused a medial rotation of the vocal folds toward the glottal midline, resulting in adduction of the anterior portion of the glottis and significant increase in vocal fold eigenfrequencies. This vocal fold-stiffening effect of TA activation also reduced the posterior adductory effect of LCA activation.