The muscles that attach the tongue are the extrinsic muscles of the tongue. Inside the tongue, there are four pairs of intrinsic muscles that can alter the shape of the tongue for talking and swallowing.
The dorsum (top side) of the tongue can be divided into two parts, an oral part that lies mostly in the mouth, and a pharyngeal part (posterior third of the tongue) which faces backwards to the oropharynx. The two parts are separated by a V-shaped groove, the sulcus terminalis (or terminal sulcus).
The dorsal side of the anterior two-thirds (oral part) of the tongue is covered in taste buds (or papillae), and the tongue appears velvety and pink. There are four types of taste buds: filiform, fungiform, vallate and foliate. At the back of the oral part of the tongue there are 3-14 vallate papillae arranged in a V-shape in front of the sulcus terminalis.
There are no lingual papillae on the underside of the tongue. It is covered with a smooth mucous membrane, with a fold (the lingual frenulum) in the centre.
The upper side of the posterior tongue (pharyngeal part) has no visible taste buds, but it is bumpy because of the lymphatic follicles lying underneath. These follicles are known as the lingual tonsil.