The larynx, which is the upper part of the airway, connects to the pharynx from above and goes down into the trachea (figure 8-3). Three odd-shaped cartilages (discoid, annular, and hypoglossal) and three even-shaped (funnel-shaped, pinkish, and wedge-shaped) form the laryngeal scaffold. The odd thyroid cartilage forms on the neck a characteristic hauteur called the”Adam’s Apple”. The laryngeal cartilages are connected to the hyoid bone, the trachea and ligaments between them.
The part of one of the ligaments connecting the thyroid cartilage with the annular forms the vocal ligaments, which limit the glottis. The internal muscles of the larynx expand and narrow the gap. The larynx as a whole is covered with a mucous membrane of the respiratory type. For clinical purposes, the larynx is divided into three floors:
the upper floor of the so-called laryngeal vestibule is bounded from the front by the free edge of the vocal folds, laterally by the nasolabial folds and from the back by the nasolabial folds (nasolabial cartilages), to the bottom reaches the level of the vocal folds,
the middle floor is a vocal chasm bounded by vocal folds,
the lower floor is the area below the vocal folds called the sub-vocal area.
The larynx, in addition to being a section of the respiratory tract, is an organ of the voice. Voice acting is the result of vibration of the vocal cords called vocal folds. The pitch of the voice depends on the length of the vocal folds, their tension, frequency of vibration and exhaust air pressure. The timbre of the voice depends on the structure of the pharynx, the nasal cavity and partly the paranasal sinuses.