The Nasopharynx

The upper part of the pharynx above and behind the hard palate is referred to as the nasopharynx. It lies close to the skull base and the posterior openings (choanae) of the nose. It contains the adenoids and the openings of the Eustachian tubes (Figure 22.1).

Adenoids

Adenoids are a collection of lymphoid tissue (Figures 22.2 and 22.3). They are part of a circle of lymphoid tissue known as Waldeyer’s ring that surrounds the entrance to the pharynx and respiratory tract. The other parts of the ring include the lingual tonsils on the base of the tongue and the pharyngeal tonsils.

Adenoids are very small at birth, reach maximum size at the age of about 5–7 years, and then regress. Adults have little or no adenoid tissue. They have the same function as lymphoid tissue elsewhere (i.e. to mount an immunological response to infection).

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