The jaw angle is enlarged, mostly accompanied by bite muscle hypertrophy, the patient’s facial shape is wider and more trapezoidal facial shape, the side view is male jaw angle, lack of soft, smooth contour. Treatment is based on jaw angle osteotomy and partial bite muscle resection The biggest difficulty of jaw angle hypertrophy osteotomy is the exposure of the jaw angle. The intra-oral method has a small and deep field of view, revealing about 3cm of incision in the angle of the jaw, which is easier to reveal and has a clear field of view, but the scar of the surgical incision that is revealed locally is regretted by patients and doctors. There are four main types of Oriental facial shapes: melon, oval, round and square. The oval face shape can show the feminine, gentle and quiet. The aspect type can set off the male’s swartness and rigidity. Therefore, face shape has gender characteristics to a certain extent. Not only does it weaken women’s temperament and charm, but it is also not conducive to the change of hair style, so women often have the requirement to change their square face to oval face. A harmonious and beautiful midface and lower face depends on a well-developed mandible (especially the angle of the jaw) and a clearly discernible slight depression in the cheek. If the cheek fat pad is further removed to make the cheek slightly depressed, a more beautiful oval shape can be obtained. Buccal fat pad is a fatty tissue located in the cheek, which still exists even in extremely thin people, and is the main cause of cheek bloating and round face shape. The buccal fat pad is a “sacrificial” tissue, its function is mainly in the masticatory muscle between the smooth liner role, after the removal of no obvious adverse effects ah. Many scholars believe that muscle function and soft tissue tension are factors that affect the shape of the jaw. Dutedoo’s study found that the growth rate of bone is particularly high in the mandible attached to the strongly contracted bite muscle, and the strong contraction of the bite muscle exerts force on the mandibular angle where the muscle is attached, causing hyperplasia of the bone cortex during the growth period, which may be one of the reasons for the excessive distance between the mandibular angle. Therefore, removing the inner layer of the bite muscle not only reduces the distance between the jaw angle, but also prevents the recurrence of bone growth in the jaw angle after osteotomy. The reduced function after removal of the inner layer of the occlusal muscle can be compensated by the temporalis muscle, the internal pterygoid muscle and other ascending jaw muscles, and the function of opening and closing the mouth will not be significantly affected. Some people use the method of measuring the circumference of the cut muscle to estimate the amount of resection, although this method is not precise enough, but it is desirable to make the left and right symmetry based on the evidence. The square face is characterized by a wide angle of the jaw and the front of the ear, first described by Legg in 1880 and surgically corrected by Gurney in 1947. The traditional procedure is to remove the bulging jaw angle and the hypertrophied bite muscle. Although this procedure can change the face shape, it often fails to achieve the oval face shape desired by oriental women, but a round face (i.e. baby face). For this reason, our improved method is to adopt a comprehensive reshaping surgery by amputating the enlarged mandibular angle and part of the hypertrophic bite muscle as well as removing the buccal fat pad, so that the postoperative shape becomes more oval. The buccal fat pad is located between the occlusal muscle, smiling muscle and zygomaticus major muscle, and the superficial surface of the posterior part of the buccal muscle, and is a leaf-like raised fatty mass covered by a membrane, extending upward to the temporal fossa and downward into the pterygomandibular space. Its blood supply comes from a rich network of vascular anastomoses between the external maxillary artery and facial veins. The buccal fat pad is the main supporting tissue of the cheek. Bite muscle: an oblong muscle located lateral to the ascending branch of the mandible. Although it can be anatomically divided into three layers, it can only be divided into an outer (i.e. superficial) and inner (i.e. middle) layer in the mandibular angle. The outer layer is the largest, starting from the maxillary zygomatic process and the first 2/3 of the lower edge of the zygomatic arch, and ending at the mandibular angle and the lower half of the ascending mandibular branch. The inner layer starts in the deeper part of the anterior 2/3 of the zygomatic arch and ends at the upper part of the ascending branch of the mandible and the rostral process. The blood supply is mainly branches of the internal maxillary artery and the returning vein is the posterior facial vein. Mandible: divided into the body, ascending branch and angle. The mandibular canal is located in the lower skull, and its entrance is 15.70±l.70mm from the posterior edge of the ascending branch of the mandible, and the ascending branch descends in the middle of the ascending branch of the mandible, 20.45±2.09mm from the angle of the mandible, and the body section is located in the upper part of the mandibular body, 11.6l±1.83mm from the lower edge of the mandible, and then ends at the chin hole, with a total length of 54.46±3.09mm. 13mm from the posterior edge of the ascending branch of the mandible, and 15mm from the angle of the mandible. It is safe to osteotomy in the L-shaped area which is 13mm from the posterior edge of the mandibular ascending branch, 15mm from the mandibular angle and 9mm from the lower edge of the mandibular body, and the possibility of damaging the inferior alveolar neurovascular bundle is small. The thickest part of the mandible was the molar area (13.00±l.22mm), followed by the joint (11.13±1.70mm) and the chin hole area (10.49±1.13mm), while the thinnest part was the mandibular angle (6.33±1.38mm) and the posterior margin of the mandibular ascending branch (6.94±1.0lmm). This indicates that the main masticatory pressure-bearing area of the mandible is in the molar region, while the inferior frontal angle and the posterior edge of the ascending branch are non-main masticatory pressure-bearing areas, and amputation of part of the mandibular angle and the posterior edge of the ascending branch will not affect the function of the mandible. X-ray surface tomography The comparative analysis of X-ray surface tomography measurements of square face women and normal dentition women shows that the ascending mandible, mandibular angle and mandibular body of square face women are significantly larger than those of normal dentition women, especially the mandibular angle, which can be osteotomized in a wider range and is therefore safer. Surgical methods: 1. Osteotomy of the mandibular angle: a 6-8 cm long incision is made in the mouth along the anterior line of the mandibular ascending branch down to the vestibular groove of the mandibular second molar, reaching the periosteum, and the occlusal muscle is completely separated from the lateral plate of the mandibular ascending branch together with the medial periosteum by using a periosteal stripper, and the parotid duct and the external maxillary artery as well as the anterior vein are not damaged during the operation. The medial pterygoid muscle of the mandibular angle is then dissected with a periosteal dislodger. The Linder f retractor is placed on the posterior edge of the ascending mandible and the angle to fully expose the mandibular angle. The desired bone block is removed with a rifling or oscillating saw while flushing. The type of osteotomy is divided into vertical sagittal osteotomy, oblique osteotomy, inverted L-shaped osteotomy and T-shaped osteotomy. If the operation is difficult, a small auxiliary incision can be made along the lower edge of the mandible 1-2cm so that the saw can be extended into the surgical area to complete the osteotomy operation. 2. Partial bite muscle resection: insert the periosteal stripper from the anterior edge of the bite muscle between the inner and outer layers of the muscle, downward to the submandibular edge and upward to the plane of the near zygomatic arch, so that the inner and outer layers of the bite muscle are completely separated. Use a long hemostatic forceps to clamp the lower end of the inner layer of the bite muscle as far as possible at the lower edge of the jaw and the lower frontal angle, and another hemostatic forceps to clamp the upper end of the inner layer without reaching the lower edge of the zygomatic arch (because the main muscle that causes the aspect type is the lower part of the bite muscle), remove the muscle between the two forceps, and measure its circumference to estimate the amount of resection to ensure symmetry between the left and right. 3, removal of buccal fat pad: use hemostatic forceps to purely separate the buccal muscle fibers from the mucosa and submucosa layer of the incision, cut the buccal fat pad envelope, gently press the cheek, the buccal fat pad can be herniated from the incision, clamp and lift for blunt separation, except for its posterior side, the buccal fat pad is very easy to separate from the surrounding tissues, try to remove it all. 4.After the removal of soft and hard tissues in the mandibular angle, the wound was rinsed, a drainage strip was placed, the incision was closed with mattress plus interrupted method, and pressure bandage was applied for 2 days. Dexamethasone was given for 3 days after surgery to prevent oropharyngeal edema and antibiotics for 3-6 days to prevent infection, and the stitches were removed after 1 week.