On each side, the cricothyroid muscle is one of muscles of the larynx affecting the vocal folds. It originates from anterior and lateral parts of the cricoid cartilage. It passes posteriorly and superiorly to insert into the:
- anterior aspect of the inferior horn of the thyroid cartilage
- inferior border of the lamina of the thyroid cartilage
It acts to tilt the thyroid cartilage anteriorly. This has the effect of increasing the distance between the thryroid and arytenoid cartilages. Consequently, the vocal ligaments are made more taut. This increases the pitch of the voice.
Cricothyroid is innervated by the external laryngeal nerve, a branch of the superior laryngeal branch of the vagus nerve (X). It is the only intrinsic laryngeal muscle not supplied by the recurrent laryngeal nerve.