Anatomy General 0fc29d23 Thyroarytenoid muscle causes A Adduction of vocal cord B Tenses vocal cord C Relaxes vocal cord D Closes inlet of larynx High-Yield Explanation Thyroarytenoid muscle is relaxor of vocal cord. Vocalis muscle which is medial fibre of thyroarytenoid, causes tension in anterior ⅓ and relaxation in posterior ⅔ of vocal cord.