The trigeminal nerve is the fifth cranial nerve and runs down each side of the face; medically you will see it written as a roman numeral (V). Therefore, the three branches of the nerve are referred to as V1 (ophthalmic), V2 (maxillary), and V3 (mandibular). Most of the function of the trigeminal nerve is sensory, which means it transmits pressure, touch, pain, and temperature signals to the brain. Only the mandibular branch of the trigeminal nerve has some motor (controls movement) function.
In some atypical trigeminal cases, other nerves may be affected, including the 9th cranial nerve, which may send pain down the back of the tongue and down the throat. Sometimes symptoms may be felt in the scalp or the ear.