The pharynx is a muscular tube located behind the nose, mouth and larynx. It is wider at the upper end and divided into three parts - the nasopharynx behind the nose, the oropharynx behind the mouth, and the laryngopharynx connecting to the esophagus. The pharynx serves as an airway for breathing and a passageway for food and acts to warm, humidify, and protect the air and assist in speech. It is associated with structures like the skull, vertebrae, tonsils, and auditory tubes.