The diagrams above show the tongue and muscles in the tongue. These muscles are
not, strictly speaking, muscles of facial expression but can make visible changes in facial appearance nevertheless.
There are more muscles in these areas than illustrated here.
Bottom: Tongue muscles.
The tongue is composed of muscle tissue with a coating of sensors (dorsal surface)
for taste, heat, pain, and tactile information.
In the lower diagram, the upper sensory surface of the tongue is shown
on the upper right side of the drawing,
and the tip of the tongue is visible above the sectioned mandible.
The side of the tongue is then peeled-away to show the muscles.
Some tongue muscles are inside the tongue, make up most of the mass of the tongue,
and shape and move the tongue.
These muscles include the Lingualis inferior (and superior, transverse, and vertical, not shown).
Other tongue muscles begin outside the tongue with only terminal fibers inside it,
and control its movement.
These muscles include the Styloglossus, the Hyoglossus, Palatoglossus, Pharyngoglossus, and Genioglossus.