Oropharynx

At a glance

English

Oropharynx

Latin (TA2)

Pars oralis pharyngis

System

Digestive

Region

Whole body

Side

Single, on the midline

About the oropharynx

The oropharynx lies directly behind the oral cavity. Above, it is bounded by the underside of the soft palate with its uvula, where it meets the nasopharynx; below, it reaches the hyoid bone and the tip of the epiglottis, where the laryngopharynx starts. Its back wall lies in front of the second and third cervical vertebrae, covered by the constrictor muscles and the mucous membrane.

In front, it opens into the mouth through the oropharyngeal isthmus, the gap framed by the soft palate above, the palatoglossal arches on either side and the tongue below. Below that opening, the front wall is formed by the pharyngeal (back) third of the tongue. Between the root of the tongue and the epiglottis lie two small pits, the epiglottic valleculae, separated by a midline fold. On each side wall, between the palatoglossal arch in front and the palatopharyngeal arch behind, is the tonsillar fossa holding the palatine tonsil.

Both food and air use this passage, so its lining is a tougher, non-keratinised stratified squamous epithelium that resists wear. During swallowing the tongue pushes the food back, the soft palate seals off the nose above, and the larynx rises under the epiglottis so that the bolus slides past the airway. The palatine and lingual tonsils, with the pharyngeal tonsil above, form most of Waldeyer's lymphoid ring.

Sore throat with inflamed tonsils (tonsillitis) is common, and a collection of pus beside a tonsil, a quinsy, can push the uvula to the other side and make opening the mouth painful. Small objects such as fish bones often catch in the tonsils or valleculae. The oropharynx is also a site for squamous cell cancers, which are often first noticed as a painless lump in the neck.

Function and supply

Function

Shared passage for air between nose and larynx and for food from mouth to oesophagus; its tonsils trap inhaled and swallowed infection.

Nerve supply

Sensory and most motor supply from the pharyngeal plexus, built from the glossopharyngeal and vagus nerves; the glossopharyngeal nerve also carries the gag reflex afferents.

Blood supply

The ascending pharyngeal artery, tonsillar and ascending palatine branches of the facial artery, and dorsal lingual branches of the lingual artery.