Which muscles are the vocal fold adductors in Adductor SD?

• A. Lateral Cricoarytenoid, Interarytenoid, Thyroarytenoid
• B. Posterior Cricoarytenoid
• C. Cricothyroid
• D. Superior Thyroarytenoid

Answer: (A)

In Adductor SD, the voice becomes strained because the vocal folds are pulled together by the adductor muscles. The muscles that actually close the glottis are the lateral cricoarytenoid, the interarytenoid, and the thyroarytenoid (including the vocalis portion). Lateral cricoarytenoid rotates the arytenoids toward the midline, bringing the vocal processes together. Interarytenoid fibers run between the arytenoids to help seal the posterior glottis. Thyroarytenoid lies within the vocal folds and shortens/thickens them, aiding edge-to-edge contact. Together, these muscles produce the adduction characteristic of Adductor SD.

The posterior cricoarytenoid is the main abducter, pulling the vocal folds apart, so it’s not responsible for the excessive closing seen in this condition. The cricothyroid mainly lengthens and tenses the vocal folds to adjust pitch, not to close the glottis. A muscle term sometimes encountered as superior thyroarytenoid isn’t typically treated as a separate primary adductor in standard descriptions; the key adductors are the lateral cricoarytenoid, interarytenoid, and thyroarytenoid.