Definition of Bell's palsy

Bell's palsy: Paralysis of the facial nerve, the nerve that supplies the facial muscles on one side of the face. Bell's palsy is also called facial nerve paralysis.

The cause of facial nerve paralysis is often not known, but is thought to be due to a virus. The facial nerve is the 7th cranial nerve.

The disease typically starts suddenly and causes paralysis of the muscles of the side of the face on which the facial nerve is affected.

Treatment is directed toward protecting the eye on the affected side from dryness during sleep. Massage of affected muscles can reduce soreness. Sometimes prednisone is given to reduce inflammation during the first weeks of illness.

The prognosis (outlook) with Bell's palsy is generally good. About 80% of patients recover within weeks to months. Conversely, about 20% of patients do less well.

The condition was originally described in 1830 by the great Scottish-born anatomist and neurologist Sir Charles Bell (1774- 1842). The word "palsy" is a corruption (and contracture) of the French word "paralysie" which means "paralysis."

See also: Bell, Charles for more about the man who dicovered this condition.