Which intrinsic muscle elongates the vocal cords?

The cricothyroid muscle plays a crucial role in elongating the vocal cords. This muscle is primarily responsible for adjusting the tension and length of the vocal folds, which influences pitch during phonation. When the cricothyroid muscle contracts, it pulls the thyroid cartilage downward and the cricoid cartilage upward, resulting in an increased distance between the two cartilages. This elongation of the vocal cords causes them to become taut, allowing for higher pitches.

The other muscles mentioned have different roles in vocal cord function. The thyroarytenoid muscle generally shortens the vocal folds and reduces tension, thereby lowering pitch. The lateral cricoarytenoid muscle aids in adducting the vocal folds, helping to bring them together during phonation but does not elongate them. The posterior cricoarytenoid muscle, which is the only muscle responsible for opening the vocal cords, is essential for breathing but also does not contribute to elongating the vocal cords. Therefore, the function of the cricothyroid muscle is critical for the elongation of the vocal cords, making it the correct answer.