What is the pharynx?

Structure and Functions

The pharynx, or throat, is the tube-shaped passageway that begins at the back of the nasal cavity, extends downward behind the mouth, and terminates at the fork of the esophagus and trachea, or windpipe. It comprises three sections: the nasopharynx, just behind the nose; the oropharynx, behind the mouth; and the laryngopharynx or hypopharynx, the remaining area above the esophagus. The pharynx contains lymphatic tissue to fight infection: the adenoids in the nasopharynx and the tonsils in the oropharynx. The left and right Eustachian tubes connect the nasopharynx to the ears and balance air pressure between the middle and outer ear.

Food enters the pharynx from the mouth, while air enters from the nose and mouth. The act of swallowing begins as a voluntary contraction of muscles and continues involuntarily until food passes into the esophagus. In the laryngopharynx, the epiglottis, a flap of connective tissue, prevents food and water from entering the trachea, while the soft palate of the mouth rises to block the nasopharynx so that material stays out of the nose. During vocalization, the pharynx plays a role in shaping the sounds made by the vocal cords, located just below it in the larynx.

Disorders and Diseases

Most problems in the pharynx arise from infection and inflammation. Pharyngitis, or sore throat, is an acute infection, usually from a virus or streptococcus bacteria, that is most common in children. Similarly, tonsillitis is an infection of the tonsils, quinsy (peritonsillar cellulitis and abscess) affects tissue near the tonsils, and epiglottitis is a bacterial infection of the epiglottis. Abscesses, with or without inflammation, may also occur in the pharynx; cysts known as Tornwaldt cysts may occur in the midline of the nasopharynx; and contact ulcers may result from damage to the pharyngeal tissue caused by swallowing something chemically harsh or physically abrasive or jagged.

Although not common, throat cancers
can occur in the nasopharynx and tonsils. They are usually squamous cell carcinomas and occur predominantly in males, usually due to smoking and alcohol consumption.

People with cleft palates may not have complete closure of the nasal passage during swallowing, a condition called velopharyngeal insufficiency. The condition can impair speech and give it a marked nasal sound.

Bibliography

Beers, Mark H., et al., eds. The Merck Manual of Medical Information. 2nd home ed. Whitehouse Station, N.J.: Merck Research Laboratories, 2003.

Parker, Steve. The Human Body Book. 2nd ed. New York: DK Adult, 2013.

PM Medical Health News. 21st Century Complete Medical Guide to Throat and Pharynx Disorders: Authoritative Government Documents, Clinical References, and Practical Information for Patients and Physicians. Mount Laurel, N.J.: Progressive Management, 2004.

Sasaki, Clarence T. "Introduction: Throat Disorders." Merck Manual Home Health Handbook, July 2008.

Thibodeau, Gary A., and Kevin T. Patton. Structure and Function of the Human Body. 14th ed. St. Louis, Mo.: Mosby/Elsevier, 2012.

"Throat Disorders." MedlinePlus, June 16, 2013.