This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
Abductor of vocal cords is 
Select and explain. 
A. Thyroarytenoid, B. Lateral cricoarytenoid, C. Posterior cricoarytenoid, D. Cricothyroid
C: Posterior cricoarytenoid
Answer: C: Posterior cricoarytenoid 
Explanation: 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 Chaurasia's HUMAN ANATOMY, Volume 3, 4th edition.