Understanding the Anatomy
The tongue is a thick and muscular organ. The base of tongue is very important to swallowing.
The tongue is divided into two main parts, the oral tongue and the base of tongue.

There is a line of taste buds way in the back of the tongue called the circumvallate papilla; everything behind that is the base of tongue (part of the oropharynx), and everything in front of that is the oral tongue (part of the oral cavity). If your cancer is in the oral tongue, see the article on oral tongue cancer instead.

 Oral tongue: This is the front two-thirds of the tongue. It is the part of the tongue that you can see when you open your mouth. This part of the tongue is in the oral cavity.
 Base of tongue: This part of the tongue is part of the oropharynx, which is part of the throat. The base of tongue is not part of the oral cavity. You can’t see the base of tongue just by looking in your mouth, but you can feel it if you slide your finger all the back into your throat.

The base of tongue is composed of a blanket of lymphoid tissue like the tonsils (but called lingual tonsils) sitting on the surface of the base of tongue. The tonsil tissue is covered by mucosa as the outer layer, and there is muscle that lies deep in the tonsils and is responsible for the movement of the tongue base.

The base of tongue can’t really be seen just by looking in your mouth, but tumours in the area can be felt by sliding a finger way back along the tongue (careful, this might make you gag). Other anatomical structures that are important to know about include:
 Vallecula: This is bottom end of the base of tongue, where it joins with the epiglottis via the glossoepiglottic fold.
 Lateral pharyngoepiglottic folds: This is where the base of tongue transitions over to the side wall of the pharynx.