Bell's palsy is an unexplained episode of facial muscle weakness or paralysis. It begins suddenly and worsens over 48 hours. This condition results from damage to the facial nerve (the 7th cranial nerve). Pain and discomfort usually occur on one side of the face or head.

The facial nerve services the muscles of the face, the ear, salivary and tear glands, and provides some of the sensations of taste on the tongue. This nerve enters the skull via a small opening in the petrous temporal bone at the base of the skull.

In Bell's palsy, the facial nerve swells and the resulting inflammation disrupts the relay of nervous system messages. The paralysis can be partial or total. It is thought that the inflammation and swelling of the facial nerve is caused by some type of viral infection or autoimmune system response.

Bell's palsy is not considered permanent, but in rare cases, it does not disappear. Currently, there is no known cure for Bell's palsy; however, recovery usually begins 2 weeks to 6 months from the onset of the symptoms. Most people with Bell's palsy recover full facial strength and expression.

Learn more about Bell's Palsy through our educational images: