The trigeminal nerve is a mixed cranial nerve that originates from just above the jawline of the face. It is responsible for the transmission of sensory data like pressure, temperature and pain as well as for motor function of the muscles involved in chewing.
There are several theories regarding the causes of trigeminal neuralgia. It was initially thought to have been caused by the compression of the trigeminal nerve in the opening from the inside to the outside of the skull. Newer research suggests that the pressure on the trigeminal nerve originates from an enlarged blood vessel, probably the superior cerebellar artery. The pressure results in damage to the myelin sheath that protects the nerve, resulting in hypersensitivity and an erratic functioning of the nerve. This results in shooting pain at the slightest stimulation of the area around the nerve. At the end of the stimulation, the nerve may be unable to shut off the pain signals.
Other possible causes of trigeminal neuralgia include: