The pharynx is a tube made of fibers and muscle enclosing a musculomembranous lined passage continuous with the nasal cavity (nasal pharynx), oral cavity (oral pharynx), and the larynx (laryngeal pharynx). Accordingly, The pharynx is multi-functional. As a component of the digestive system, it aids food in beginning its passage to the stomach. It also helps route air to the larynx, trachea, and the lungs. Finally, the pharynx acts as a resonating chamber for the sounds produced in the larynx.

The outer walls of the pharynx are made of three circularly arranged muscles, which are called constrictors. The superior pharyngeal constrictor overlaps with the middle pharyngeal constrictor, which itself overlaps with the inferior pharyngeal constrictor. The arrangement has been described as three rings stacked one inside the other.

The inner walls of the pharynx are made of three muscles that are oriented...