High Quality Content by WIKIPEDIA articles! The vocal muscle is the upper portion of the thyroarytenoid muscle which is primarily involved in producing speech.It arises in front from the lower half of the angle of the thyroid cartilage, and from the middle cricothyroid ligament. Its fibers pass backward and laterally, to be inserted into the base and anterior surface of the arytenoid cartilage.The lower and deeper fibers of the muscle can be differentiated as a triangular band which is inserted into the vocal process of the arytenoid cartilage, and into the adjacent portion of its anterior surface; it is termed the Vocalis, and lies parallel with the vocal ligament, to which it is adherent