The pharynx is divided into three sections from top to bottom: the nasal pharynx, which is situated behind the back of the nasal openings, the oral pharynx, found behind the entrance of the oral cavity; and the laryngeal pharynx, located behind the opening of the larynx. First, the nasal pharynx is connected only to the respiratory system, allowing air to flow from the nasal cavities through it. Additionally, on the lateral surface at the back of the nasopharynx, there are two openings, one on each side, known as the auditory tubes (Eustachian tubes or pharyngotympanic tubes), which are surrounded by raised areas of mucous membrane called tubal elevations. These tubes link to the middle ears (tympanic cavities) at the back and primarily help equalize pressure and drain secretions from the middle ears. Second, the oral pharynx continues from the oral cavity and serves to move the bolus down to the laryngeal pharynx below.