<prompt> Abductor of vocal cords isThyroarytenoidLateral cricoarytenoidPosterior cricoarytenoidCricothyroid  <response>: Abduction of vocal cords is by Posterior cricoarytenoid only. Posterior Cricoarytenoid is a triangular muscle. - Origin: Posterior surface of the lamina of the cricoid cailage. Origin is medial to inseion. - Inseion: Its fibres pass upwards and backward to the inseed into, the anterior aspect of muscular process of the arytenoid cailage. Ref: BD Chaurasias HUMAN ANATOMY, Volume 3, 4th edition. 