To better understand tonsillitis, it helps to understand the anatomy of the throat and tonsils.

The pharynx is the back, upper part of the throat behind the tongue. It starts at the base of the tongue and ends at the larynx.

Anatomy examples:

• Normal pharynx in an adult
• Normal pharynx in a child
• Normal tongue

The tonsils are collections of lymphoid tissue in the back of the throat. They are located on both sides of the throat, near the base of the tongue. The tonsils generally shrink over time. At puberty, the tonsils are normally about the size of an almond.

Anatomy examples:

• Normal anatomy of the pharynx
• Normal tonsils in a child