The trigeminal nerve is a mixed cranial nerve, and is the thickest facial nerve in the body. The trigeminal nerve is the fifth pair of cranial nerves, which consists of general somatosensory fibers and special visceral motor fibers, including three branches of the ophthalmic nerve, maxillary nerve and mandibular nerve. The ophthalmic nerve contains somatosensory fibers, which emanate from the trigeminal ganglion and eventually travel to the skin of the head and face above the fissure of the eye, the eyeball, the conjunctiva, and part of the mucosa of the paranasal sinuses, including the frontal nerve, the lacrimal nerve, and the nasociliary nerve: 1. The nasociliary nerve: in the deep surface of the superior rectus muscle, it can be divided into several branches, which are distributed in the skin of the lacrimal sac, nasal mucosa, eyeball, lower lid, and nasal dorsum. The maxillary nerve contains general somatosensory fibers and is a sensory nerve, consisting of the infraorbital nerve, superior alveolar nerve and zygomatic nerve: 1, infraorbital nerve: distributed on the skin of the lower lid, upper lip, lateral part of the nose and cheek, once damaged, it will lead to disorders in the innervated area. The zygomatic nerve is relatively small and is located in the skin of the zygomatic area, and if it is damaged, it will lead to sensory impairment in the distribution area. The mandibular nerve is composed of special visceral motor fibers and general somatosensory fibers, and is a mixed nerve. The motor nerve innervates the temporalis muscle, the occlusal muscle, and the pterygoid muscle. A common clinical condition is trigeminal neuralgia. Patients often experience unbearable knife-like pain, which seriously affects normal life and work and requires early treatment to relieve the discomfort.