The conus elasticus is a membrane that lies under the mucous membrane connecting the cricoid cartilage with the thyroid and arytenoid cartilages. It is composed of dense fibroconnective tissue with abundant elastic fibres. It extends superiorly from the anterior arch of the cricoid cartilage and attaches to the thyroid cartilage anteriorly and the vocal processes of the arytenoid cartilages posteriorly. The free superior margin of the conus elasticus is thickened to form the vocal ligament, which forms the deep part of the vocal folds. It has a thickened middle portion known as the middle crocothyroid ligament and a thinner lateral part known as the lateral crocothyroid membrane.