Which of the following is an intrinsic laryngeal muscle?

• A. Stylohyoid
• B. Thyroarytenoid
• C. Omohyoid
• D. Sternohyoid

Answer: (B)

Intrinsic laryngeal muscles stay inside the larynx and move the vocal folds themselves, directly shaping phonation. The thyroarytenoid is part of the vocal folds, forming their main body and including the vocalis portion that can fine-tune tension. When it contracts, the vocal folds shorten and relax, altering pitch and voice quality from within the larynx.

The other muscles listed are extrinsic—they attach the larynx to outside structures like the hyoid bone or sternum. They move the entire larynx up or down or change its position, rather than adjusting the tension or length of the vocal folds themselves.

So, the muscle that is intrinsic to the larynx and directly influences the vocal cords is the thyroarytenoid.