Orthognathic malformation refers to abnormalities in the volume and shape of the jaws, the relationship between the upper and lower jaws and other bones of the craniofacial skeleton caused by abnormalities in the development of the jaws, and the accompanying abnormalities in the relationship between the jaws, teeth, and the function of the oral and maxillofacial system, as well as abnormalities in the shape of the face. The main target of orthognathic surgery is developmental dentofacial deformity. Maxillofacial deformities can be categorized into: anteroposterior developmental abnormalities of the jaws, such as maxillary protrusion, maxillary retrusion, mandibular protrusion, mandibular retrusion, etc.; vertical developmental abnormalities of the jaws, such as open-close, long-face syndrome, short-face syndrome, etc.. Abnormalities of horizontal development of the jaw, such as wide face deformity occlusal hypertrophy, mandibular angle hypertrophy and other chin deformities, such as underdevelopment or overdevelopment of the chin; facial asymmetry deformities, such as hemifacial short deformity, unilateral overdevelopment of the mandible, hemi-mandibular angular hypertrophy, and progressive hemifacial atrophic deformity. Tips: The angle of mandible (angleofmandible) is the intersection of the posterior edge of the mandibular branch and the lower edge of the mandibular body, and the size of the angle is related to the age and the size of the chewing force. The bone surface of the inner and outer areas of the angle of the mandible is rough and astringent, with the attachment of the masticatory muscle, the attachment of the internal pterygoid muscle and the attachment of the mandibular ligament in the stem, the angle of the mandible is one of the bony anatomical symbols on the surface of the maxillofacial area, and is commonly used in the measurement of the craniofacial area.