Why does my face feel numb?

Facial numbness is a very common phenomenon. If the facial numbness is occasional and short-term, you can observe it first. If the symptoms disappear, you don’t have to worry too much. If the facial numbness persists for a long time and it is always a numb feeling and does not disappear for a long time, then you need to pay attention to it. It may be caused by a facial disease, and the facial numbness may be caused by facial neuritis.

What causes facial neuritis?

Facial nerve edema, myelin sheath, etc., when the face is blown by cold wind, the nutritional microvessels of the facial nerve spasm, causing local tissue ischemia and hypoxia leading to facial neuritis. Facial neuritis is also related to viral infection. For example, geniculate ganglion syndrome is caused by herpes zoster virus infection, which causes inflammation of the geniculate ganglion and facial nerve, leading to facial neuritis.

Facial neuritis is a common and frequently occurring disease in life, regardless of age. Patients with facial neuritis often cannot complete even the most basic movements such as raising eyebrows, closing eyes, and puffing lips. Patients with facial neuritis generally show symptoms of facial paralysis.

Facial neuritis is more common among cranial nerve diseases, which is related to the anatomical structure of the facial nerve canal, which is a long and narrow bony canal. Some patients with facial neuritis may have a narrower facial nerve canal, which may be the intrinsic cause of facial neuritis. Otogenic, traumatic, tumoral, central, etc. can also cause facial neuritis.

What are the symptoms of facial nerve palsy?

Bell's sign: This sign is an important sign of peripheral facial nerve paralysis. When the eye is closed, the paralyzed eyeball moves upward (or inward), exposing the sclera under the cornea. This phenomenon is a coordinated movement and is essentially a physiological phenomenon. When the facial nerve is paralyzed, this phenomenon is easy to observe. When a normal person closes his eyes, if his upper eyelid is turned up, the Bell's phenomenon can also be seen.

Hyperacusis: It is occasionally seen in peripheral facial nerve paralysis. The mechanism of hyperacusis (exaggerated hearing) is: the tensor tympani muscle that keeps the eardrum tense is innervated by the internal pterygoid nerve which is a branch of the trigeminal nerve, and the stapedius muscle is innervated by the facial nerve. The two muscles are in an antagonistic relationship to maintain balance. When the facial nerve is paralyzed, the stapedius muscle is paralyzed. As a result, the tensor tympani muscle is relatively tense, the tension of the tympanic membrane is high, and small sounds produce strong vibrations, resulting in hyperacusis and lesions of the facial nerve above the branches of the stapedius muscle.

Platysma sign: This sign occurs in both central and peripheral facial nerve palsy. The patient is asked to flex his head forward, and the examiner applies resistance on the patient's forehead. At this time, the platysma muscle on the healthy side contracts, while the paralyzed side does not contract.

Tongue deviation: It is mostly an illusion and is related to the incorrect position of the lips. After the corners of the mouth are artificially corrected, the tongue will no longer be deviated. However, tongue deviation may be seen in some cases. If this phenomenon occurs, the tongue always deviates to the healthy side, which is exactly the opposite direction of the tongue deviation associated with central facial nerve paralysis. The explanation for the tongue deviation caused by peripheral facial nerve paralysis is that it is caused by paralysis of the styloglossus and palatoglossus muscles innervated by the facial nerve.