The ring consists of the following (from top to bottom): • 1
pharyngeal tonsil (or "adenoid"), located on the roof of the nasopharynx, under the sphenoid bone. • 2
tubal tonsils on each side, where each
auditory tube opens into the nasopharynx • 2
palatine tonsils (commonly called "the tonsils") located in the oropharynx •
lingual tonsils, a collection of lymphatic tissue located on the back part of the
tongue Terminology Some authors speak of two pharyngeal tonsils/two adenoids. These authors look at the left and right halves of the pharyngeal tonsil as two tonsils. Many authors also speak of lingual tonsils (in the plural), because this accumulation of lymphoid tissue consists of several little prominences – many smaller rounded masses. Whether to collectively call all these a single tonsil or separate tonsils is to an extent an arbitrary decision.
Variation There also normally is a good amount of
mucosa-associated
lymphoid tissue (
MALT) present between all these tonsils (intertonsillar) around the ring, and more of this lymphoid tissue can variably be found more or less throughout at least the naso- and oropharynx.
Development The tubal tonsils usually develop from an accumulation of lymphoid tissue in the pharyngeal tonsil. ==Clinical significance==