The trigeminal nerve is the fifth pair of cerebral nerves, the thickest pair of cerebral nerves in the skull (the left and right branches are called a pair), and is a mixed nerve. What is a mixed nerve? The nervous system refers to nerves that manage both motor and sensory functions as mixed nerves. After the trigeminal nerve originates from the pontocerebral center, it divides into motor and sensory roots. The former innervates the movement of the temporalis and masticatory muscles; the latter manages the sensation of pain, temperature and touch in the face. The sensory root is thicker than the motor root and divides into three branches within the trigeminal hemimelia. The perineurium of the anterior medial part of the trigeminal hemimelia forms the first branch, the ophthalmic branch; the middle part forms the second branch, the maxillary nerve; and the posterior lateral part forms the third branch, the mandibular nerve. These three nerves exit the skull via the superior orbital fissure, foramen ovale and foramen ovale respectively, and are distributed in the frontal area, brow arch, orbit, nasal cavity, paranasal area, upper lip, cheek and zygomatic area, lower lip, mandible, preauricular area, external auditory canal and temporal skin; as well as the oral mucosa, palate, tongue, upper alveolus, lower alveolus and tooth roots. ”The nature of pain can be described as lightning or electric shock-like, knife-like, burning and needle-like severe pain; the duration of pain often varies from a few seconds to several minutes, and the duration of pain in advanced patients is significantly longer, which can reach half an hour to several hours; the pattern of pain is sudden onset There are “trigger points” in the upper lip, nasal side, lower lip and jaw skin and oral mucosa, tongue and upper and lower teeth, etc., and touching or pressing this “trigger point” can induce Therefore, patients are afraid to speak loudly, and eating, washing, brushing or breezing can lead to recurrent pain attacks. If a patient with similar pain is relieved by the drug carbamazepine, the pain can be diagnosed as “trigeminal neuralgia”. In addition, the trigeminal nerve innervates the upper and lower alveoli. One third of trigeminal neuralgia is clinically manifested as severe toothache, and patients often go to dentistry first, where the teeth and gums are normal. In addition to toothache, trigeminal neuralgia also has pain in the skin of the face, oral mucosa, tongue and other parts of the face, and there are “trigger points” when touching the upper lip, lower lip, paranasal area and jaw. The prevalence of trigeminal neuralgia is 182 per 100,000 people, with an annual incidence of 3-5 per 100,000 people, mostly occurring in adults and the elderly, with the age of onset between 28-89 years old, 70%-80% of cases occurring above 40 years old, with a peak age of 48 years old The onset of the disease is mostly unilateral, with right-sided pain accounting for 61%, left-sided 38% and bilateral 1%. The pain of branch I is 5%, branch II is 41%, branch III is 37%, branch I + II is 3%, branch II + III is 13%, branch I + II + III is 1%. Trigeminal neuralgia caused by tumor compression is called secondary trigeminal neuralgia, which accounts for about 7.3% of trigeminal neuralgia. Among them, cholesteatoma is the most common, accounting for 3%, followed by trigeminal nerve sheath tumor, auditory neuroma, meningioma, hemangioma and nasopharyngeal tumor. It is worth noting that 26% of trigeminal neuralgia occurring under the age of 30 is caused by tumors. Therefore, those who have trigeminal neuralgia, especially young patients, must undergo systemic examinations such as cranial CT and magnetic resonance imaging (MRI) in a timely manner.