Tasks | Trigeminal nerve

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The motor fibers of the trigeminal nerve are mainly responsible for innervating the masticatory muscles. In addition, they also supply small muscles of the palate, which are important for the swallowing process, and of the ear to protect it from excessive noise. Muscles of the mouth floor are also innervated by this nerve.

These are also relevant for the swallowing process. The sensitive fibers of all three branches of the nerve are used for the sensation of touch and pain in the entire face. The eye branch is responsible for the orbit, the nasal cavity and the forehead area, the upper branch for the middle face and also for parts of the nasal cavity, as well as for the upper jaw with gums and teeth. The lower jaw branch supplies the lower face, the oral cavity and parts of the tongue.

Paralysis

Trigeminal paresis or trigeminal paralysis can manifest itself in various symptoms. This depends on where the lesion occurs and which branch of the nerve is affected. If the branch of the eye is affected, it leads to sensory disturbances in the upper part of the face.

In addition, the eyelid closure reflex is weakened or even no longer triggerable. Then the eye is no longer closed reflexively when a foreign body touches the cornea. Paralysis of the maxillary branch impairs the sensation in the central part of the face.

Paresis of the lower jaw branch also manifests itself in sensory disturbances in the corresponding area. In addition, however, there is a loss of function of the chewing muscles. This leads to a deviation of the lower jaw from the paralyzed side in the case of unilateral paralysis.

Paralysis of the individual branches is often caused by an increase in pressure on the affected nerves, for example due to a brain tumor or aneurysm. Circulatory disorders and inflammation of the nerves can also lead to these symptoms. Paralysis of the entire trigeminal nerve, on the other hand, is caused by the complete severing of the nerve.

This is where all symptoms come together. Paralysis can occur on one or both sides. If paralysis of the lower jaw branch occurs on both sides, chewing is impossible and if the paralysis lasts for a long time, the chewing muscles regress.