Within facial paralysis there are numerous causes. One of the reasons of facial paralysis is something called Bell's Palsy. What Bell's Palsy is, is the actual inflammation of the facial nerve, and it could occur from a variety of causes, but it's most notably associated with a viral infection such as that which occurs with a common cold. it is sort of a widely used term for facial paralysis, but it really should be used as a focus term for that particular condition where we just don't know why the paralysis has occurred. The causes of facial paralysis can be many. Patients can be born with it or have the congenital types and there are various syndromes and conditions that go along with that such as Moebius Syndrome. Or they can have a traumatic incident later in life, such as in a car accident or an injury of or laceration to the nerve itself. Other causes can include more rare phenomenon such as a brain tumor or an arterial venous malformation in the brain that can compress a very critical part of the brainstem itself where the nerve originates. There are many more causes of facial paralysis, and it's important for the clinician to diagnose and differentiate what it is that's causing the actual paralysis because the treatments are then, tailored based on that particular diagnosis.