Which muscle is primarily responsible for vocal fold abduction?

• A. Posterior cricoarytenoid
• B. Cricothyroid
• C. Interarytenoid
• D. Lateral cricoarytenoid

Answer: (A)

Opening the vocal folds, or abduction, is carried out mainly by the posterior cricoarytenoid. When this muscle contracts, it rotates the arytenoid cartilages, pulling the vocal folds away from the midline and widening the glottal opening. This action is essential for breathing.

Other muscles have different roles: the cricothyroid tilts the thyroid cartilage forward to lengthen and tense the vocal folds, increasing pitch; the lateral cricoarytenoid and the interarytenoids bring the vocal folds together (adduct) to close the glottis for phonation and protection. So, the posterior cricoarytenoid is the primary muscle responsible for vocal fold abduction.