Cricothyroid muscle

The cricothyroid muscle attaches to the anterolateral aspect of the cricoid and the inferior cornu and lower lamina of the thyroid cartilage, tilting the thyroid forwards and tensing the vocal cords. It is the only laryngeal muscle supplied by the external laryngeal nerve (rather than the recurrent laryngeal nerve).

Action
The Cricothyreoidei produce tension and elongation of the vocal folds by drawing up the arch of the cricoid cartilage and tilting back the upper border of its lamina; the distance between the vocal processes and the angle of the thyroid is thus increased, and the folds are consequently elongated.

Innervation
This muscle is innervated by the external laryngeal branch of the vagus nerve.