Trigeminal Neuralgia in its ‘classic’ form occurs when a blood vessel or artery is compressing the 5th cranial nerve called the Trigeminal Nerve. There are two Trigeminal nerves, one located on the right side of the brain and one on the left. The nerve controls all facial and oral sensitivity and muscle/tissue interaction. The compression from the artery or blood vessel wears away the myelin sheathing causing the brain to trigger seizure like lightning bolts to the affected side of the head and face.
Trigeminal Neuralgia affects 1 in 15,000 people. It currently has no cure and is not typically subject to manageable treatments. It has been described as the suicide disease and "the worst pain known to humankind".