The etiology and pathogenesis of primary trigeminal neuralgia are still unclear. Most believe that the lesion is within the trigeminal meningeal ganglion and its sensory nerve roots, but it may also be related to mechanical compression and pull on the nerve caused by small vascular malformations, bony malformations in the rocky bone and other factors, as well as nutritional and metabolic disorders. Secondary trigeminal neuralgia, also called symptomatic trigeminal neuralgia, is often a clinical symptom of a disease, such as caused by tumors, inflammation, trauma and lesions in the cerebellar pontine angle and its adjacent areas, as well as in the branches of the trigeminal nerve. It is classified according to the site of occurrence: into bilateral and unilateral trigeminal neuralgia. It can be further divided into: first branch pain; second branch pain; third branch pain; first and second branch pain; second and third branch pain, first, second and third branch pain. The site of onset is more on the right side than on the left side. Pain involvement is most common in 2 and 3 branches at the same time, respectively, and single branch involvement is more frequent in the second branch. Clinical features: the onset of pain is paroxysmal. Except for the fear of prolonged pain, the patient does not have any pain during the second attack. When seizures occur, they seem like lightning-like stabs. Pain episodes often appear as sudden, paroxysmal, and can last 15 min or longer, with the frequency of episodes ranging from a few times a day to several times a month. The characteristics are as follows: 1. The site of pain does not extend beyond the innervation of the trigeminal nerve and is often confined to one side. Although all three branches can be involved, the second and third branches are most frequently involved, accounting for about 95%. 2.The nature of the pain is episodic electric shock-like, knife-like and tear-like pain, with sudden onset and stop. The pain starts from the jaw or alveolus and radiates along the innervation area, each pain lasts for several seconds to tens of seconds, and may last for several minutes. The seizures often increase in frequency, shorten the interval and intensify the pain with the prolongation of the disease, and frequent seizures may affect eating and rest. 3, triggering factors and “trigger points” Pain attacks are often triggered by random facial movements such as talking, chewing, brushing teeth and washing face, or by touching a certain area of the face (such as the upper lip, paranasal, supraorbital orifice, infraorbital orifice and oral gums). These sensitive areas are called “trigger points” or trigger points. 4. Other symptoms The attack may be accompanied by twitching of the same side muscles, facial flushing, lacrimation and salivation, which is also called painful twitching. In order to relieve the pain, the patient often rubs the same side of the face to relieve the pain (in fact, it does not relieve the pain). Over time, the facial skin becomes rough, thickened and the eyebrows fall off. To avoid seizures, patients are afraid to eat and wash their faces, and their faces are emaciated and depressed. 5. Physical signs Objective examination is mostly free of trigeminal nerve deficits and other limited neurological signs. Occasionally, herpes may appear in one of the innervation areas, which is caused by herpes zoster virus infection in the semilunar ganglion. Secondary trigeminal neuralgia refers to pain in the area of the trigeminal nerve distribution caused by various lesions involving the trigeminal nerve roots, the hemianopsia or the nerve trunk. It is characterized by long duration of pain attacks, often lasting several minutes to tens of minutes, or persistent pain with paroxysmal aggravation. On examination, the pain is characterized by hyperalgesia, loss of sensation or hypersensitivity in the area of trigeminal nerve innervation, mostly involving the first and third branches. The involvement of the first branch may result in a blunted corneal reflex, while the involvement of the third branch may result in weakness and atrophy of the masticatory muscles. In addition, other positive signs of the primary disease may also be present.