Part One: Characteristics and Causes of Trigeminal Neuralgia

II.  Anatomy of the Trigeminal Nerve



     The trigeminal nerve is the fifth of twelve pairs of cranial nerves enervating the face and head, and is denoted by the Roman Numeral V. It has three divisions which enervate the forehead and eye (ophthalmic V1), cheek (maxillary V2) and lower face and jaw (mandibular V3). The trigeminal nerves function in sensing facial touch, pain and temperature, as well as controlling muscles used for chewing. The trigeminal nerve functions should be distinguished from the facial nerve (cranial nerve VII), which controls all other facial movements.     

     The three divisions of the trigeminal nerve come together in an area called the Gasserion ganglion.  From there, the trigeminal nerve root continues back towards the side of the brain stem, and inserts into the pons. Within the brain stem, the signals traveling through the trigeminal nerve reach specialized clusters of neurons called the trigeminal nerve nucleus.  Information brought to the brain stem by the trigeminal nerve is then processed before being sent up to the brain and cerebral cortex, where a conscious perception of facial sensation is generated.