What Is the Pharynx?

The pharynx (Greek pharynx = throat; pharanx = gulf, chasm) is a cavity within the throat that serves as an air and food passage. The other main part of the throat is the larynx.

Functions of the Pharynx

Functions of the pharynx include:

1. Swallowing

When food or fluid enters the pharynx, muscle contraction — swallowing reflex — pushes it toward the esophagus. Disorders of swallowing — dysphagia — can be caused by dry mucous membrane, dry food, disorders in the pharyngeal wall, psychological reasons or neurological disorders.

Touching of the soft palate or the back wall of the pharynx with the finger can trigger vomiting reflex.

2. Breathing

Pharynx carries air from the nose and mouth toward the larynx. Inflamed adenoids or tonsils, sudden swelling from an insect bite or allergic reaction, stuck food or detached dentures, or injury of the pharynx can all impede breathing.

3. Speech

Pharynx, together with the larynx, tongue and soft palate, helps to form sounds.

4. Equilibration of the Pressure in the Middle Ear

The pharynx is connected with the middle ear on both sides with Eustachian tubes (Picture 1). These enable equilibration of pressure differences between the throat and the middle ear built during quick changes of altitude, diving or in disorders of the middle ear.

5. Immunity

Tonsils and (in children) adenoids (Picture 1) can catch some microbes and foreign particles thus preventing them to enter the lungs.

Picture 1: Tonsils are located on both sides of the oropharynx and
adenoids on the top of the nasopharynx.
Eustachian tube connects the nasopharynx and the middle ear.
(source: Healcentral.org)

Pharynx Anatomy

Pharynx is a vertical tube lying behind the nasal and oral cavity. Its walls are built from striated (voluntary) muscles, covered by mucosal layer on its inner side.

The part of the pharynx lying behind the nasal cavity is called the nasopharynx (Lat. nasus = nose). In children, a mass of lymphatic tissue — the pharyngeal tonsil or adenoids – is protruding into the nasopharynx from its roof. Above the pharynx roof, the sphenoidal sinus — one of the paranasal sinuses — is located.

The part of the pharynx seen through the mouth is called the oropharynx (Lat. os, or- = mouth). The lingula is hanging down from its frontal edge. There is one tonsil located on each side. Normal tonsils can be small and not visible or quite prominent when checked in a mirror (Picture 2). Symmetrically enlarged and reddened tonsils are seen in acute inflammation; in chronic inflammation, tonsils can be shrunk. From asymmetric tonsils or lingula pharyngeal a pharyngeal cancer can be suspected.

Phto of pharynx, soft palate, lingula and tonsils

Picture 2: Oral part of the pharynx as seen through the mouth.
(source: Wikimedia)

The bottom part of the pharynx, lying behind the larynx is called the laryngopharynx.

The back part of the pharynx continues downward into the esophagus, and its front part into the larynx. During swallowing, the entrance of the larynx is covered by a muscular fold – epiglottis.

Common Conditions Involving Pharynx

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Article reviewed by Dr. Greg. Last updated on January 7, 2012