Left and right Eustachian tubes connect the corresponding left and right middle ears (tympanic cavities) to the back of the nose and throat, and function to allow the equalization of pressure in the middle ear air cavity with the outside (ambient) air pressure. The membrane-lined tubes, also called the auditory tubes, serve to drain secretions from the middle ear to the nasopharynx region. The Eustachian tubes are normally closed to prevent a back fill of fluid and particulate debris from the mouth and nose. Muscles in the throat and palate area control the opening and closing of the tubes. When subjected to pressure the tubes may collapse or fail to open unless pressurized. Some disease processes, especially chronic ear infections, may obstruct the tubes and result in a painful difference in pressure between the middle ear and the pressure found in the nose and throat.

Chronic...