The maxillary nerve is a branch of the trigeminal nerve, which consists of the ophthalmic nerve, the maxillary nerve and the mandibular nerve, while the maxillary nerve is a sensory nerve, which generally passes through the round foramen to exit the cranium, and can be basically divided into four segments, including the pterygopalatine fossa segment, the mid-cranial fossa segment, the intra-orbital segment, and the facial segment; the mid-cranial fossa segment distributes in the dura mater, while the pterygopalatine fossa generally emits the zygomatic nerve, and the facial segment issues in the infra-orbital foramen, and the intraorbital segment enters into the infraorbital fissure and can be changed to the infraorbital nerve, which generally gives off the middle superior alveolar nerve and the anterior superior alveolar nerve. The maxillary nerve is usually smaller than the mandibular nerve, which is the largest. The maxillary nerve manages pain sensation in the location of the maxillary posterior teeth, so when treating posterior teeth intraorally, a block anesthesia of the maxillary nerve can be performed, usually injected in the location of the maxillary tuberosity, which ensures that the number of anesthesia sessions can be reduced to a good effect when treating the posterior teeth or when extracting multiple posterior teeth.