Trigeminal neuralgia is a disorder of the trigeminal nerve, which provides the sense of pressure, touch, pain and temperature in the head and face. The trigeminal nerve also provides some control of jaw movement but it does not control other face movement such as closing eyes or smiling. You have two trigeminal nerves, one on each side of your head. These nerves originate deep inside your brain near the base of your skull. After the trigeminal nerve leaves your brain and and travels through your skull, it divides into three smaller branches which provide sensation throughout your face. In most cases, the pain is due to a malfunction of the trigeminal nerve. The exact causes of malfunction are not known but are felt to include:

• Pressure of a blood vessel on the root of the trigeminal nerve where the nerve leaves the brain(this is believed to be the most common cause)
• Pressure of a tumor on the trigeminal nerve
• A symptom of inflammatory disease of the brain such as multiple sclerosis (usually in advanced stages of MS)
• Physical damage to the nerve caused by dental or surgical procedures or injury to the face or infections
• A stroke affecting the lower part of your brain