To get a correct idea of the throat we should look into the wide-open mouth of some friend. Depressing the tongue we can readily see the back wall of the pharynx, which is common to the two main avenues leading to the lungs and the stomach. Above, we notice the air passages, which lead to the posterior cavities of the nose. We have already described the hard palate, the soft palate, the uvula, and the tonsils (Fig. 46). On looking directly beyond these organs, we see the beginning of the downward passage,—the pharynx. If now the tongue be forcibly drawn forward, a curved ridge may be seen behind it. This is the epiglottis, which, as we have already learned shuts down, like the lid of a box, over the top of the larynx (secs. 137 and 203). The throat is lined with mucous membrane covered with ciliated epithelium, which secretes a lubricating fluid which keeps the parts moist and pliable. An excess of this secretion forms a thick, tenacious mass of mucus, which irritates the passages and gives rise to efforts of hawking and coughing to get rid of it. 350. The Larynx. The larynx, the essential organ of voice, forms the box-like top of the windpipe. It is built of variously shaped cartilages, connected by ligaments. It is clothed on the outside with muscles; on the inside it is lined with mucous membrane, continuous with that of the other air passages. Illustration: Fig. 148.—View of the Cartilages in front project and form the lages and Ligaments of the “Adam’s apple,” plainly seen and Larynx. (Anterior view.) A, hyoid bone; B, thyro-hyoid membrane; C, thyroid cartilage; D, erico-thyroid membrane; E, cricoid cartilage, lateral ligaments seen on each side; F, upper ring of the trachea. (“Adam’s apple” is in the V-shaped groove on a line with B and C.) The larynx has for a framework two cartilages, the thyroid and the cricoid, one above the other. The larger of these, called the thyroid, from a supposed resemblance to a shield, consists of two extended wings which join in front, but are separated by a wide interval behind. The united edges in front project and form the “Adam’s apple” plainly seen and easily felt on most people, especially on very lean men. Above and from the sides rise two horns connected by bands to the hyoid bone from which the larynx is suspended. This bone is attached by muscles and ligaments to the skull. It lies at the base of the tongue, and can be readily felt by the finger behind the chin at the angle of the jaw and the neck (sec. 41 and Fig. 46). From the under side of the thyroid two horns project downwards to become jointed to the cricoid. The thyroid thus rests upon, and is movable on, the cricoid cartilage.