Nasopharynx

The nasopharynx is that part of the nasal passage that lies above the free border of the soft palate. The anterior wall extends from the choanae to include the incomplete floor formed by the postero-superior surface of the soft palate. On its lateral walls the nasopharynx communicates with the right and left tympanic cavities by the Eustachian tubes.

The two main types of epithelia lining the nasopharynx are stratified squamous (comprising approximately 60% of nasopharyngeal epithelium) and pseudostratified columnar respiratory-type epithelium containing ciliated cells, goblet cells and basal cells. The interphase between these two epithelia is sharp in some areas with an intermediate epithelium intervening in other areas. Both the pseudostratified columnar and intermediate epithelium comprises approximately 40% of the nasopharyngeal epithelium.

Numerous seromucinous glands and collections of small lymphocytes are present in the submucosa throughout the nasopharynx, with higher density at the opening of the eustachian tubes into the nasopharynx.