Seventh cranial nerve paralysis: Known as Bell's palsy, this is paralysis of the facial nerve, the nerve that supplies the facial muscles on one side of the face. The cause of Bell's palsy is not known, but it is thought to be related to a virus (or to various viruses). Bell's palsy typically starts suddenly and causes paralysis of the muscles of the side of the face on which the facial nerve is affected. (The facial nerve is also known as the 7th cranial nerve). The treatment of Bell's palsy 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) of Bell's palsy is generally good. About 80 percent of patients recover within weeks to months. Conversely, about 20% of patients do less well. The condition was originally described in 1830 by the Scottish anatomist and neurologist Sir Charles Bell (1774- 1842). The word "palsy" is a corruption (and contracture) of the French word "paralysie" which means "paralysis."