The glottis is a part of the larynx; an orifice that is visible at the back of the throat. Situated between the two vocal cords, its opening allows air to pass into the lungs, between the trachea and the laryngopharynx. The air in the glottis also causes the vocal cords to vibrate, making it indispensable to phonation. Finally, the glottis prevents the passage of liquids and solid elements into air passages, especially during the swallowing of food. Diseases of the glottis may engender dysphonia or paralysis, in the case of laryngitis or a tumor.