The larynx is a cartilaginous segment of the respiratory tract located in the anterior aspect of the neck. The primary function of the larynx in humans and other vertebrates is to protect the lower respiratory tract from aspirating food into the trachea while breathing. It also contains the vocal cords and functions as a voice box for producing sounds, i.e., phonation. From a phylogenetic view, the larynx in humans has achieved its highest evolutionary development with the capacity to articulate speech, which is absent in invertebrates and fishes. The larynx is about 4 to 5cm in length and width, with a slightly shorter anterior-posterior diameter. It is smaller in women than men, and larger in adults than children owing to its growth in puberty. A large larynx correlates with a deeper voice.