Tongue Musculature : Types , Origin and Insertion of tongue muscles
The extrinsic tongue musculature includes the :
- genioglossus, and
- hyoglossus muscles.
They connect the body of the tongue to the nearby bone structures to give it its ample mobility within the oral cavity (Thiele et al. 1992).
The intrinsic tongue musculature is made up of the :
- transverse, and
- vertical muscles of the tongue.
They help to change the shape of the tongue.
Extrinsic tongue musculature
The styloglossus muscles pull the tongue back and up. If one muscle acts unilaterally, the tongue becomes concave. With hypofunction the third phase of the swallowing reflex will be absent (Thiele et al. 1992). The genioglossus can move the dorsum of the tongue downward, pull the border of the tongue forward, and help extend the tongue. Hyperfunction of the genioglossus results in tongue thrusting. The hyoglossus lowers the body of the tongue and pulls the tongue back. Its hyperfunction results in a sunken tongue (Thiele et al. 1992).
Intrinsic tongue musculature
Diagram of the internal tongue muscles and their positions in relation to the muscles of the floor of the mouth. The longitudinal muscles of the tongue shorten the tongue. The transverse muscles bring the borders of the tongue closer together. Hypotonus of these fibers leads to a widened tongue. The vertical muscles make the tongue flatter and wider, and their hyperfunction frequently accompanies lateral tongue thrusting, which can cause widening of the dental arch.