It is a well-known fact that tongue is one of the strongest muscles in the body, but it isn’t a single muscle out there. The movement of the tongue is important in not just speaking but also in swallowing and manipulation of food for mastication. The tongue is kept moist by the saliva and it is richly supplied by the blood vessels and nerves.
Let’s talk about the muscles of the tongue. These are classified into intrinsic and extrinsic muscles. How do they differ?
The intrinsic muscles of the tongue are not attached to the bone and they are responsible for altering the shape of the tongue. There is a total of four pairs of intrinsic muscles.
The extrinsic muscles are paired, a total of four pairs of muscles help in changing the position of the tongue and they are attached to a bone.
Extrinsic muscles of the tongue
It arises from the mandible (lower jaw) and it is helpful in protruding the tongue. The upper fibers of this muscle retract the lip, middle fibers depresses the tongue and lower fibers are responsible in protrusion of the tongue. Genioglossus is also called the safety muscle of the tongue as it is the only one that moves the tongue forward.
It arises from the Hyoid bone and the function of this muscle is to retract and depress the tongue.
It arises from the styloid process of the temporal bone, and the function of this muscle is to draw the sides of the tongue up, so as to create a trough that helps in swallowing of the food.
It arises from palatine aponeurosis, and the function is to depress the soft palate and move the palatoglossal fold towards the midline so as to elevate the back of the tongue helping in swallowing or deglutition of the food.
Intrinsic muscles of the tongue
These muscles are attached to only the other parts of the tongue, and they originate and attach within the tongue without having any attachment to a bone. The intrinsic muscles help in altering the shape of the tongue, lengthen and shorten it, curling and uncurling of the apex and edges of the tongue when rolling it, and flattening and rounding of the surface.
The ultimate function of the intrinsic muscles is to facilitate speech, swallowing, and eating.
Superior longitudinal muscle
This muscle runs along the upper surface, lying just under the mucous membrane. It elevates itself to assist in retraction of, or deviation of the tip of the tongue. The dorsum of the tongue is made concave by this muscle and shortens it too.
Inferior longitudinal muscle
This muscle is joined to the styloglossus muscle and it lines the sides of the tongue. The action of this muscle is to make the tongue shorter and dorsum of the tongue convex.
This muscle is located in the middle of the tongue. It attaches to the superior and inferior longitudinal muscles. The action of the Verticalis muscle is to broaden and flatten the tongue.
This muscle is responsible for the division of the tongue at the middle and is attached to the mucous membrane that runs along the sides of the tongue. The function of this muscle is to narrow the tongue and elongate it.
These were the extrinsic and intrinsic muscles of the tongue.