The temporalis muscle is a masseter muscle in humans. The skeletal muscle is located at the level of the temple. It helps to close the jaw.
What is the temporalis muscle?
The temporalis muscle is a skeletal muscle located in the facial region of the human face. It is called the temporalis muscle because it extends below the temple on both sides of the face. At the same time, it extends down to the lower jaw. Its function is to help close the lower jaw. The masticatory muscles of the human jaw include a total of four muscles. They all have different functions in regulating the masticatory process. The four muscles perform all the functions involved, such as opening or forcefully closing the lower jaw. Mobility in all directions is controlled by them. The four masseter muscles are the masseter muscle, the temporalis muscle, the pterygoid medialis muscle and the pterygoid lateralis muscle. While the masseter muscle works very closely with the pterygoid medialis muscle, the pterygoid lateralis muscle and temporalis muscle have other roles. Beyond jaw closure, the temporalis muscle is responsible for enabling mandibular retraction. Of all four masticatory muscles, the temporalis muscle is the strongest muscle of the masticatory apparatus.
Anatomy and structure
The Vth cranial nerve is the trigeminal nerve. It supplies large parts of the face with its nerve branches. In addition, it is responsible for the motor function of the masticatory apparatus with its branches. The mandibular nerve in particular assumes this function. It is the second branch of the trigeminal nerve. It contains sensitive nerve fibers which, among other things, supply the facial masticatory system. In addition, it accommodates motor parts. These are further divided into several sub-branches. They include the masseteric nerve, which innervates the masseter muscle. The nervi temporales profundi supply the temporalis muscle. The pterygoid nerves are responsible for supplying the lateral pterygoid muscle and the medial pterygoid muscle. The last sub-branch is the mylohyoid nerve, which is responsible for supplying the floor muscles of the mouth. The temporalis muscle begins its course at the temporal fossa. This is a bulge on the skull near the temple. Extensive and fan-shaped, the temporalis muscle spreads out in this area. It extends to the mandible of the masticatory apparatus.
Function and tasks
Like all other muscles of the masticatory apparatus, the temporalis muscle has an important role in the movement of the lower jaw. Its main functions are to close the mandible and to allow the mandible to move backward. The masseter muscle forms a unit together with the pterygoideus mediales muscle. They wrap around the mandible like a sling, increasing their force during the closing process. In contrast, the temporalis muscle works largely alone. In direct comparison with the other masticatory muscles, the temporalis muscle is the strongest sphincter of the masticatory apparatus. It raises the lower jaw and thus enables the mouth to close. The masticatory muscles are significantly involved in the comminution of food. The movements of the jaw break down the ingested food into small pieces so that subsequent digestion can take place. This involves chewing until the individual elements of the food are of a size that can initiate the swallowing process. Elements that are too large make the swallowing process difficult or impossible. Closing the lower jaw enables biting off during food intake. Only by closing the lower jaw can this possibility of food intake take place at all. In addition, the muscles of the masticatory apparatus are significantly involved in the formation of speech. Without them, the sound formation required for speaking or singing would not be possible to a sufficient degree. Some sounds are only formed by raising and lowering the lower jaw. The preliminary work of sound formation takes place in the larynx and the glottis. It is refined and completed by the movement of the jaw.
Diseases
Occurring pain in the masticatory system is experienced by people as particularly painful. Many patients report attacks of pain, usually related to the teeth.Teeth complaints have a direct effect on the entire masticatory apparatus. Misalignments, faulty dentures or inflammation of the nerves in the entire mouth and throat area cause problems when chewing. The masticatory muscles are closely connected to the head, neck and back muscles. As soon as there are problems with the chewing muscles, there is usually pain with the other muscles as well. Headaches or tension are among the most common symptoms. Others are nocturnal teeth grinding or jaw misalignment. As soon as the temporalis muscle suffers lesions, the lower jaw can no longer be moved backwards. This has a direct impact on the grinding of food. Furthermore, rotational movements of the mandible are then no longer possible. Lesions are conceivable after accidents, fractures of the jaw or during surgical procedures in the throat or mouth area. In addition, impairment of the temporalis muscle can lead to changes as well as restrictions in speech formation. Sounds can no longer be pronounced correctly if the jaw cannot make its movements to a sufficient degree. This can lead to misunderstandings in everyday life and even make professional singing impossible.
