What is the function of the cricothyroid muscle in relation to vocal folds?

The cricothyroid muscle plays a crucial role in modulating the tension and length of the vocal folds, making it primarily a glottal tensor. When the cricothyroid muscle contracts, it causes the thyroid cartilage to tilt forward and downward relative to the cricoid cartilage. This action effectively stretches the vocal folds, increasing their tension. Higher tension in the vocal folds contributes to higher pitch in the sound produced, which is essential in phonation.

By increasing the tension of the vocal folds, the cricothyroid muscle allows the larynx to produce a wider range of pitches. This control over pitch modulation is vital for speech and singing. Therefore, its function as a glottal tensor directly impacts vocal quality and pitch regulation, highlighting its significance in the anatomy and physiology of speech.