Which muscles are responsible for tense (tensor) action of the vocal folds?

• A. Thyromuscularis
• B. Lateral cricoarytenoid and posterior cricoarytenoid
• C. Cricothyroid (CT) and Thyrovocalis (Vocalis)
• D. Oblique arytenoid and interarytenoid

Answer: (C)

The amount of tension in the vocal folds is controlled mainly by two muscles. The cricothyroid tilts the thyroid cartilage forward, which lengthens the vocal folds and makes them stiffer. The thyrovocalis, the vocalis portion of the thyroarytenoid, lies within the vocal folds and, when it contracts, tightens them from inside, increasing tension further. This combination is what produces the tense, stretched state of the folds needed for higher pitches.

The other muscles mentioned don’t tense the folds: lateral cricoarytenoid and posterior cricoarytenoid mainly abduct (open) the vocal folds, while oblique arytenoid and interarytenoid contribute to closing or stabilizing the glottis rather than increasing tension.