The Cricothyroid is classified as an external laryngeal muscle. The cricothyroid arises from the anterior arch of the cricoid and has two parts: a straight medial part which is inserted into the lower margin of the thyroid cartilage, and an oblique part which is inserted into the anterior border of the inferior horn.

With the thyroid cartilage fixed in postion, the cricothyroid tilts the cricoid and produces a rough adjustment of the tension of the vocal folds. The actions of the laryngeal muscles are either tensor (cricothyroid and vocalis) or postioning-opening (posterior cricoarytenoid) or closing (lateral cricoarytenoid and transverse arytenoid).