Nasopharynx

At a glance

English

Nasopharynx

Latin (TA2)

Pars nasalis pharyngis

System

Digestive

Region

Whole body

Side

Single, on the midline

About the nasopharynx

The nasopharynx is the top chamber of the throat. It sits under the body of the sphenoid and the basilar part of the occipital bone and continues down to the level of the soft palate, below which the oropharynx begins. In front it opens widely into the two nasal cavities through the choanae. Its roof and back wall run in a continuous curve down to the level of the atlas. Unlike the lower parts of the pharynx it is a purely respiratory passage, and because it is held open by bone above, it does not collapse.

Each side wall carries the opening of the auditory (pharyngotympanic) tube, about level with the lower nasal concha. The opening is ringed above and behind by a rounded ridge, the torus tubarius, raised by the end of the tube's cartilage. Two folds of mucous membrane run down from that ridge: the salpingopharyngeal fold, containing the muscle of the same name, and in front a smaller salpingopalatine fold. Behind the torus lies a deep slit, the pharyngeal recess.

Lymphoid tissue in the roof and back wall forms the pharyngeal tonsil, called the adenoids when enlarged. Smaller patches surround the tube openings as the tubal tonsils. These are the upper part of Waldeyer's ring, the ring of lymphoid tissue guarding the entrance to the air and food passages. The lining here is mostly ciliated, pseudostratified respiratory epithelium that moves mucus downwards.

The auditory tube lets air into the middle ear so that pressure on both sides of the eardrum is equal; it opens during swallowing and yawning. In children, enlarged adenoids can block the nose, causing mouth breathing and snoring, and can obstruct the tubes, leading to repeated middle-ear infections or fluid in the ear. The pharyngeal recess is the most common starting point for nasopharyngeal carcinoma, which may first show as a lump in the neck or a blocked ear on one side.

Function and supply

Function

Conducts air from the nasal cavities to the oropharynx and ventilates the middle ear through the auditory tubes; its lymphoid tissue guards against inhaled infection.

Nerve supply

Sensory supply mainly from the maxillary nerve via the pharyngeal branch from the pterygopalatine ganglion, with glossopharyngeal fibres lower down.

Blood supply

The ascending pharyngeal artery, pharyngeal branches of the maxillary artery and the ascending palatine artery.