With the improvement of people’s quality of life, people’s demand for beauty is also getting higher and higher, and the facial appearance of the jaw has become the focus of most attention, and Oriental women recognize “melon face” and “goose egg face” as a beautiful face shape. The “square face” formed when the jaw angle is enlarged is considered to be more manly. For women with an enlarged jaw angle, more often with the help of jaw surgery to obtain the appearance of beauty. First, the anatomy of the mandible The mandible is bow-shaped, by the “U” shape of the mandibular body and the mandibular body is nearly perpendicular to the mandibular ascending branch, the intersection of the two parts that is the mandibular angle. The outer part of the mandibular angle is the coarctation of the bite muscle, with the attachment of the bite muscle, and the inner part is the coarctation of the pterygoid muscle, with the attachment of the internal pterygoid muscle. The tendon attachment of the mandibular angle needs to be fully stripped during surgery. The inferior alveolar nerve and vascular bundle enter through the mandibular foramen of the ascending branch of the mandible and travel through the mandibular canal and exit through the chin foramen. The mandibular marginal branch of the facial nerve is located behind the facial artery at the jaw margin and is covered by fascia on the surface. On the deep side of the fascia, the nerve passes between the submuscular tendon of the broad cervical muscle and the mandibular body. In normal face, the mandibular angle on both sides of the same individual is basically symmetrical, but it varies greatly from individual to individual, and the average normal angle is 120 degrees. 1. Adjacent structures of the mandible The relationship between the facial artery and the mandible. The facial artery emanates from the external carotid artery and enters the face at the anterior edge of the occlusal muscle at the lower edge of the mandible, flattening the plane of the lower edge of the mandible. The inferior chin artery branches from the facial artery to the skin and subcutaneous tissue of the mandibular fossa, the submandibular lymph nodes, the submandibular glands, and the periosteum of the mandible. An additional 8.3% have a paracentral subchin artery, which is located in the superficial structures of the subchin region. The subchin artery gives off dermal, muscular, and glandular branches as it travels medially and anteriorly, and 83.3% of the submandibular periosteal branches are present. The subchin artery has one to two accompanying veins, mostly one branch, all of which converge into the facial vein. 2.The relationship between the mandibular margin branch of facial nerve, buccal branch and parotid duct and mandible The mandibular margin branch of facial nerve is mostly single trunk type, accounting for 57.6%, double trunk type accounting for 25.7%, and combined trunk type accounting for 16.7%. The branches traveled above the mandibular rim (76.6%) and below the mandible (23.4%), and were located within 1.5 cm above and below the mandibular rim, respectively. The location of the parotid gland is near the intersection of the angle of the mandible and the posterior border of the mandibular branch 1 cm above the angle of the mandible, 4 cm from the posterior border of the mandibular branch and 1 cm from the inferior border of the mandible. 3. The morphology and blood supply of the buccal fat body The buccal fat body is located on the deep side of the superficial musculotendinous system of the face, and there is a small lobulated yellow mass of adipose tissue between the masticatory muscles. It is covered with a thin connective tissue membrane. The overdeveloped cheek fat body can make the cheek tissue protrude, the “cheek fossa” disappear, the facial contour line is not obvious, presenting a plump, obese face, and lose the harmonious beauty, and this kind of hypertrophy of the cheek fat body will not shrink with the decrease of subcutaneous fat due to the increase of age, and can be removed by surgery. Second, the cause of jaw angle hypertrophy and diagnostic criteria Etiology The specific causes of jaw angle hypertrophy have reached a consensus on two aspects: the bony factors of the mandible and the soft tissue factors of the bite muscle. The bony factors of the mandible include localized bone tissue hyperplasia of the mandibular angle, exostosis of the ascending mandible, hypertrophy of the mandibular body, and abnormal development of the entire mandible. Soft tissue factors of the bite muscle include use-related hypertrophy of the bite muscle and hyperplasia of the muscle fibers due to genetic factors. For example, due to dietary habits, more women in areas where chewing-resistant pancakes are the main food have an aspect type. Classification Oriental jaw angle hypertrophy is generally divided into 3 categories: 1. hypertrophy of the jaw angle protruding downward and backward; 2. rolled outward; 3. a combination of the first two types. At the same time, some scholars also classify mandibular hypertrophy into four categories according to the etiology and clinical manifestations: 1, mild hypertrophy: the facial shape is not square, but the angle of the mandibular angle becomes smaller when observed from the side; 2, moderate hypertrophy: the mandibular angle is obviously protruding; 3, severe hypertrophy: the mandibular angle is obviously protruding and accompanied by bite muscle hypertrophy; 4, compound type: the mandibular angle is obviously protruding and accompanied by chin deformity. The latter classification in terms of etiology and clinical manifestations provides a basis for the selection of clinical procedures and facilitates the guidance of clinical operation and communication. Diagnostic criteria Due to regional and racial differences and different aesthetic concepts of individuals, the diagnostic criteria of mandibular angle hypertrophy are not uniform. Third, the treatment of jaw angle hypertrophy jaw angle hypertrophy treatment there are three ways: 1, chewing muscle hypertrophy injection face slimming technology: due to various reasons, such as night grinding teeth, lateral chewing and other habits lead to chewing muscle hypertrophy, the face is square. Treatment: injecting face slimming injection, about two weeks face automatically slim down. 2, excessive cheek fat liposuction: one is a specific part of the fat mass (medically known as cheek fat pad); the other is the same as the belly subcutaneous fat accumulation. Treatment: Through a special suction needle, the fat is sucked out or set aside to achieve the purpose of slimming the face. 3, jaw angle osteotomy: the doctor removed the widest part of the face bone – jaw angle bone part, from the frontal view of the face width narrowed, so that the face into a slim “goose egg face” or “melon face” and the development of the method. According to the operation, the main factors are: simple mandibular angle osteotomy for bony factors, mandibular plate splitting, mandibular angle osteotomy plus mandibular plate splitting, and mandibular angle osteotomy combined with other osteotomies (zygomatic bone reduction, chinplasty, etc.) and selective partial bite muscle excision, Botox A injection, selective bite muscle neurectomy and buccal fat pad removal for soft tissue factors. The procedures are classified according to the site of the surgical entrance. According to the site of the surgical entrance, there are: 1. extra-oral approach 2. intra-oral approach 3. combined intra-oral and extra-oral approach 4. Prospects With the development of computer technology, three-dimensional reconstruction technology has been gradually applied to the preoperative simulation of clinical surgery, which can more clearly carry out surgical treatment, and the aesthetic effect will be improved later. The application of endoscopic technology makes the intraoral approach more intuitive, with clearer vision, more minimally invasive surgery and better postoperative aesthetic results. With the development of industrial technology and continuous innovation in clinical operation, new instruments more suitable for surgical operation will continue to appear, which will be more conducive to the convenience of operation and better achieve bilateral symmetry.