The Study On The Applied Anatomy Of Mandibular Angle Region And Related Measurement By Three-dimensional Reconstruction

BackgroundAsian facial contours traditional aesthetic standard is "oval face" or "goose egg face ".The basifacial contour is an important factor in affecting the overall facial contour. If the mandibular angle is hypertrophy or the basifacial width is too great, it will be regarded as an ugly face. Which is the square face or the trapezoidal face, and thus lose their gentle characteristic and beautiful temperament in oriental women,. With the improvement of people's living standard and the enhancement of aesthetic consciousness, the people who has mandibular angle hypertrophy call for changing basifacial contour by plastic and cosmetic surgery is increasing. Such surgery has become one important surgery of facial plastic and cosmetic surgery.The concept of prominent mandibular angle or mandibular angle hypertrophy was put forward by Baek et al in 1989. The cause of mandibular angle hypertrophy is still not entirely clear at present, but the pathological changes is the anormal growth of mandible and/or masseteric hypertrophy, which is currently accepted by the most people. The anormal growth of mandible is more common in mandibular angle hypertrophy of Asians. The human face is to emphasize harmony and unity, but in the whole facial contours, the diagnosis of mandibular angle hypertrophy is the results of comprehensive considerations,and which is subject to influence different ethnicity, different cultural background,and so on, so there is no uniform standards of the diagnosis of mandibular angle hypertrophy. Domestic and foreign doctors and scholars did a lot of research in the diagnosis of mandibular angle hypertrophy by imageology and other means, and put forward their reasonable diagnostic criteria. Wang Xia et al did some statistics on the lateral X-ray films of the mandibular angle and thought the angle of mandibular angle less than 110°can be diagnosed the mandibular angle hypertrophy. TAO Hong-Wei et al thought the width of mandibular angle equal to or greater than the width of the zygoma can be diagnosed the mandibular angle hypertrophy and thought the angle of mandibular angle less than 120°also can be diagnosed it. Hu Jing et al according to the X-ray film of mandibular angle hypertrophy thought that the diagnostic criteria of mandibular angle hypertrophy include:(1) The region of the mandibular angle is hypertrophy. (2) Mandibular plane angle (MP. FH angle) is less than normal. (3) In the lateral X-ray films, the opening degree of the mandibular angle become smaller than normal. (4) Lower 1/3 height of face is too short. (5) Asymmetry change. Zhou Zhi et al according to a large number of Han people dry skull measurements, thought that the ratio of facial width and mandibular width (midface width/mandibular width) for men and women are relatively concentrated around 1.33, the ratio of facial width and mandibular width can be used as one of the diagnostic criteria for male and female mandibular angle hypertrophy, Li Hui Chao et al according to the results of three-dimensional measurements of craniofacial mandibular angle hypertrophy women and proposed a clinical reference for the mandibular angle hypertrophy of diagnostic criteria on the three-dimensional measurement:①Ratio of bigonial breadth and morphological facial height is greater than 0.8;②Angle of mandibular angle is less than 120°;③∠GoMeGo is greater than 65°;④Bigonial breadth is greater than 95mm;⑤Mandibular ascending branch length is greater than 57mm;⑥Length of mandibular body is greater than 82mm,maximum width ofⅦmandibular angle region is greater than 35mm.Three-dimensional measurements with the first standard and comply with any two other standards is defined as the mandibular angle hypertrophy. The type of the mandibular angle, domestic and foreign scholars had their own point of view. Kim et al mandibular angle hypertrophy is divided into four types:(1) Mild degree:face is not square, but angle of mandibular angle was observed smaller from the side;(2) Moderate degree:mandibular angle clear abduction and predominance;(3) Severe degree:mandibular angle significant bduction and predominance associated with masseteric hypertrophy; (4) Compound type: mandibular angle significant abduction and predominance associated with microgenia deformity.Classification and operation project of mandibular angle hypertrophy:Li Hui Chao et al according to the shape of hypertrophic mandibular angle and their clinical experience they classified mandibular angle hypertrophy:Ⅰtype -- eversion type:the preferred operation project of this type is mandibular angle osteotomy plasty;Ⅱtype---decocted later predominance:the preferred operation project of this type is mandibular angle osteotomy plasty;Ⅲtype --adduction type:the preferred operation project of this type is mandibular angle osteotomy plasty or mandibular external circumferential lamella ablation;Ⅳtype--mandibular angle hypertrophy with microgenia:the preferred operation project of this type is mandibular angle osteotomy plasty or mandibular external circumferential lamella ablation with level osteotomy genioplasty or synthetic materials chin augmentation;Ⅴtype--mandibular angle hypertrophy associated with masseteric hypertrophy:selected the osteotomy plasty or mandibular external circumferential lamella ablation, according to the condition of postoperative masseter muscle atrophy determined whether need toxin injection or not; VI type-light:the preferred operation project of this type is mandibular angle osteotomy plasty.With the in-depth research and the launching of clinical related surgery, in recent years the choice of surgical procedures, complications treatment, and other aspects had been further understood and improved. Mandibular angle hypertrophy plasty in our country had become an important project in facial plastic and cosmetic surgery. As the launching of the operation, serious complications were also emerging. Mandibular angle region's main blood vessels and branches of the facial nerve injury were the most common in serious surgical complications, because the anatomical structure of mandibular angle region's blood vessels and nerves had no enough knowledge and had no good protection of these important anatomical structures. Due to lack of the recognition of overall facial contour., resulting in excessive or inadequate osteotomy, so that the proportional relationship was imbalance. As lack of knowledge for the anatomical structure of the influencement of mandibular contour, which could not be satisfactorily resolved the fluent problems of the frontal and lateral contours, result was ineffective. Such as the second mandibular angle, bilateral asymmetry, inadequate or excessive narrowing the frontal width,the lateral profile is not smooth, " horse face" deformity and so on. These complications restricted further development of such operations to some extent, increased the dispute chances between doctors and patients.Purpose and SignificanceThrough the research of the topic,we better understood the characteristics of regional anatomy of the mandibular angle,discussed the proportional relationship of the frontal head and facial skeletal contour in normal adult female,related angles of mandibular angle and their correlation of them and bigonial breadth,identified the anatomical structure of the influencement of mandibular contour, undertook the related measurement by three-dimensional reconstruction,improved the relevant diagnostic criteria of the mandibular angle hypertrophy,put forward a more reasonable note and methods to prevent the surgical complications. The research of the topic from two aspects:applied anatomy of mandibular angle region and associated measurement of mandibular angle by three-dimensional reconstruction, The findings will provid anatomical basis and theoretical basis in reducing and preventing the surgical complications and improving safety and effectiveness of the surgery. And it will help further enhance the results of operations.Methods1.1 Applied anatomical research of the mandibular angle region 1.1.1 Anatomical layer observation of the mandibular angle regionSelected 10 adult head specimens by the formalin fixation, red latex carotid artery infusion (7 males and 3 females), total 20 sides, layer by layer dissected, detailed observation anatomical level of the mandibular angle region from the shallow into the deep.1.1.2 Applied anatomy of major blood vessels in the mandibular angle regionSelected 10 adult head specimens by the formalin fixation, red latex carotid artery infusion (7 males and 3 females), total 20 sides, layer by layer dissected, determined the mandibular angle point:marked the most down, the most backward, the most predominance point of the mandibular angle as measurement point. Made general and microscopic anatomy,observe and measure. Observed courser characteristics of the facial artery, facial vein, retromandibular vein; measured the position relationship between them and the mandibular angle point.1.1.3 Applied anatomy of important nerves in the mandibular angle regionSelected 10 adult head specimens by the formalin fixation, red latex carotid artery infusion (7 males and 3 females), total 20 sides, layer by layer dissected, determined the mandibular angle point:marked the most down, the most backward, the most predominance point of the mandibular angle as measurement point. Made general and microscopic anatomiy,observe and measure.Observed Courser and branch characteristics of marginal mandibular branch of facial nerve and cervial branch of facial nerve, measured the position relationship between them and the mandibular angle point when they away from the parotid gland, measured and observed the position relationship between the marginal mandibular branch of facial nerve and the inferior border of mandible.1.1.4 Position relationship between mandibular canal and the mandibular angle,the inferior border of mandible (or the posterior border of mandibular ascending branch)Selected 10 adult head specimens by the formalin fixation, red latex carotid artery infusion (7 males and 3 females), total 20 sides, layer by layer dissected, determined the mandibular angle point:marked the most down, the most backward, the most predominance point of the mandibular angle as measurement point. Made general and microscopic anatomiy,observe and measure.The surface structure was stripped from the mandibular periosteum,mandibular angle point and third molar point were marked as the main indicator line. Separate indicator line was A:outer margin of third molar to posterior border of mandibular ascending branch,B:outer margin of third molar to mandibular angle,C:outer margin of third molar to inferior border of mandible,D, E: trisected between line C and line F and set line D and line E,F:from posterior border of mental foramen to inferior border of mandible. And sawed mandible along the indicator line, measured the distance between mandibular canal and the mandibular angle point,the inferior border of mandible (or the posterior border of mandibular ascending branch) on the transverse cross-section and observed the position relationship between the mandibular canal and inside and outside plate of mandible.1.2 Related measurements of mandibular angle by spiral CT three-dimensional reconstruction1.2.1 Measured the proportions of frontal head and facial skeletal contourRandomly selected 60 cases head spiral CT data of adult women which met the test requirements (age 20-50 years old), imported DICOM format into mimics software and carried out three-dimensional reconstruction, measured 7 items about the proportion of frontal head and facial skeletal contour on the image of three-dimensional reconstruction and calculated the relative proportions.1.2.2 Measured the related angles of mandibular angleRandomly selected 60 cases head spiral CT data of adult women which met the test requirements (age 20-50 years old), imported DICOM format into mimics software and carried out three-dimensional reconstruction, measured 8 items about the mandibular angle on the image of three-dimensional reconstruction,analyzed the correlation between the various angles, the correlation of the associated angles and bigonial breadth (basifacial breadth) by SPSS13.0 statistical software.1.2.3 Measured the anatomical structures of the influencement of mandibular contour.Randomly selected 60 cases head spiral CT data of adult women which met the test requirements (age 20-50 years old), imported DICOM format into mimics software and carried out three-dimensional reconstruction, fixed points on the four regions (the posterior border of mandibular ascending branch area, the mandibular angle area, the inferior border of mandible area,the slash area)which influenced mandibular contour (front view, lateral view) on the image of three-dimensional reconstruction, A point:2cm above the transition point between the posterior border of mandibular ascending branch area and the mandibular angle area (along the posterior border of mandibular ascending branch direction); B point:1cm above the transition point between the posterior border of mandibular ascending branch area and the mandibular angle area (along the posterior border of mandibular ascending branch direction); C point:the transition point between the posterior border of mandibular ascending branch area and the mandibular angle area; D point:the mandibular angle point; E point:the transition point between the mandibular angle area and the inferior border of mandible;F points:1cm ahead the transition point between the mandibular angle area and the inferior border of mandible area (along the inferior border of mandible direction); G points:2cm ahead the transition point between the mandibular angle area and the inferior border of mandible area (along the inferior border of mandible direction); H point:the fusion point between the slash and the inferior border of mandible;Ⅰpoint:1cm ahead of the fusion point between the slash and the inferior border of mandible (along the inferior border of mandible direction) J points:the fusion point between the slash and the mandible body; K point: the mid-point of the H point and the J point (along the slash direction). All these points were measured the thickness of mandible and the thickness of outside plate of mandible. Combined analysis of data obtained the average thickness of the mandible and the average thickness of the outside plate of mandible on the four regions.1.3 Statistical treatmentMeasurement results were input SPSS13.0 software, the first to use hypothesis testing of Kolomogorov-Smirnov normal distribution, confirmed that measurement data is normally distributed, and calculated the mean, standard deviation of the results, analyzed the proportion relationship of frontal head and facial skeletal contour and analyzed the linear correlation between the various angles, the linear correlation of the associated angles and bigonial breadth (basifacial breadth). Left and right side data carry out paired-samples t test, if P> 0.05 indicated no significant difference; if P<0.05 indicated the significant differences.1.4 Retrospective analysis of surgical options on basifacial contours plastyWe took 95 cases patients who undertook basifacial contours plasty in our hospital as research objects. We combined diagnostic criteria of mandibular angle hypertrophy on the basis of the comprehensive examination, and classified the condition of patient's basifacial contours, and choosed surgical options according to classification.Results2.1 The characteristic of anatomical layers of mandibular angle regionAnatomical layers are skin, subcutaneous fat, SMAS fascia and platysma, fascia parotidea masseterica,.which parcels parotid gland and masseter muscle,masseter muscle, periosteum of mandible, from the shallow into the deep. The large platysma-auricular ligament, fence-like masseteric ligament could be observed among the skin, SAMS fascia and fascia parotidea masseterica. Facial artery, facial vein, retromandibular vein, marginal mandibular branch of facial nerve and cervial branch of facial nerve are located in the same anatomical level. The level was under the fascia parotidea masseterica.2.2 Applied atomical characteristics of major blood vessels in the mandibular angle regionFacial artery origin from the anterior wall of the external carotid artery, through the stylohyoid muscle and posterior digastric and the deep surface of the hypoglossal nerve, to the submental triangle, through facial nerve groove above submandibular gland, to the anterior border of masseter muscle, around the inferior border of mandibular body to the face. Facial vein company with facial artery on the inferior border of mandibular body,80%(16 sides) of the facial artery located in front of facial veins,20%(4 sides) of the facial artery is located in the deep and front of facial vein. Facial vein and the mandibular vein converge the common facial vein in the submandibular area. At the anterior border of mandibular, facial artery and facial vein located superficially, marginal mandibular branch of facial nerve, platysma, thin subcutaneous fat and skin on the surface of them; deep surface of them close to the periosteum of mandible. The distance between facial artery and the mandibular angle point is (30.06±4.25)mm, the distance between facial vein and the mandibular angle point is (27.55±4.02) mm at the inferior border of mandibular.The superficial temporal vein and the maxillary vein converged the retromandibular vein behind the neck of mandible,penetrated the parotid gland, courser at the surface of the external carotid artery in front of the external acoustic pore. The retromandibular vein and the facial nerve or its main branches near a cross intersection, little parotid gland organization between them, most paste directly. The retromandibular vein and the posterior border of mandibular ascending branch is almost flat, where the wall is thin and diameter of caliber is coarse, pasted the posterior border of mandibular ascending ramus only had the periosteum,or thin-layer parotid organization between them. After the lower pole of the parotid gland,it is divided into anterior and posterior,the two branches 16 sides (80%); anterior branch injected into the facial vein, the posterior branch with posterior auricular vein merged into the external jugular vein. Four sides (20%) no anterior and posterior branch vein directly merged into facial vein. The relationship between retromandibular vein and the mandibular angle is divided into two kinds of types:①Tight connection type: retromandibular vein and its tributaries which form the arc structure is closely pasted the mandibular angle,8 sides accounted for 40%;②Loose connection type: retromandibular vein and its tributaries which form the arc structure is loosely pasted the mandibular angle,12 sides accounted for 60%. The more decoct later prominent of mandibular angle, the closer the retromandibular vein and the mandibular angle. The distance was (3.00±0.56)mm between the retromandibular vein and the posterior border of mandibular ascending branch, the distance was (12.20±1.09)mm between the retromandibular vein and the mandibular angle point.2.3 Applied atomical characteristics of important nerves in the mandibular angle regionThe marginal mandibular branch of the facial nerve is one-two, mostly one, origin from the facial cervical stem of the facial nerve after that, had undergone on the top of mandibular angle and posterior border of the masseter muscle, the location is more constant. The marginal mandibular branch of facial nerve from the parotid gland after that its courser under the masseteric fascia, cross the facial artery at anterior border of masseter muscle, the location is more constant,was not found there was no cross the facial artery; finally controlled platysma,depressor anguli oris,depressor labii inferioris, mentalis. The distance was (10.36±0.41)mm between marginal mandibular branch of the facial nerve and mandibular angle point when it was away from the parotid gland, after that its position relationship with the inferior border of mandible can be divided into three conditions:①It parallel run on the top of the inferior border of mandible,the distance was (6.84±0.70)mm between it and the inferior border of mandible,12 sides accounted for 60%, it was almost parallel crossed with facial artery at the anterior border of masseter muscle;②It generally flat the inferior border of mandible, equivalent to in thegroove between the inferior border of mandible and the submandibular gland 6 sides accounted for 30%, it was oblique crossed with facial artery at the anterior border of masseter muscle;③It run below the inferior border of mandible, the maximum of the distance between it and the inferior border of mandible was not more than 1.2cm,2 sides accounted for 10%, it was oblique crossed with facial artery at the anterior border of masseter muscle. The relationship of the marginal mandibular branch of facial nerve crossing with the facial artery can be divided into three conditions:①The marginal mandibular branch of facial nerve is located superficial to the facial artery,16 sides accounted for 80%;②It is located in the deep surface of the facial artery,2 sides accounts for 10%;③It separate two branches which retain or encircle facial artery, and then compose one branch,2 sides account for 10%. we also found that four sides,20% of the marginal mandibular branch of facial nerve anastomose with the buccal branch of facial. The distance was (6.93±0.42)mm between the marginal mandibular branch of the facial nerve and the the inferior border of mandible at the crossing of facial artery.Cervical branch of the facial nerve is the terminal branch of the facial cervical stem of the facial nerve, away from the inferior border of the parotid gland, pass behind the mandibular angle point (9.92±0.40) mm, and run the deep surface of the platysma, finally controlled platysma.2.4 Running characteristics of mandibular canal and the position relationship between mandibular canal and the mandibular angle, the inferior border of mandible (or the posterior border of mandibular ascending branch)Mandibular angle point and third molar point were marked as the main indicator line. The distance between the inferior border of mandibular canal and the mandibular angle, the inferior border of mandible or the posterior border of mandibular ascending branch in each section of mandible., separately was A:(14.52±1.21) mm; B:(16.64±0.88)mm;C:(14.1±1.00)mm;D:(12.03±0.91) mm; E:(10.26±0.98) mm;F:(15.22±1.29) mm. Observed the relationship between mandibular canal and inside and outside plate of mandible and discovered:mandibular canal full-length almost run tightly to the inside plate, the more near the rear of the mandible the tighter it attached inside plate.2.5 Measurement of the proportions of of frontal head and facial skeletal cont our by three-dimensional reconstructionThe relevant data of proportion of frontal head and facial skeletal contou r were measured on the images of head and facial three-dimensional reconstru ction:maximum cranial breadth,eu-eu:(145.13±2.95)mm;facial breadth (bizygom atic breadth),zy-zy:(133.77±4.52)mm;bigonialbreadth,go-go:(97.18±2.38)mm; eu-e u/zy-zy:1.09±0.02;zy-zy/go-go:1.38±0.03;eu-eu/go-go:1.49±0.03.v-n:(105.40±3.10) mm; upper facial height,n-sd:(69.00±2.95) mm;pr-gn:(46.58±1.97) mm; morphol ogical facial height,n-gn:(111.49±4.17)mm;v-n/n-sd:1.53±0.03;n-sd/pr-gn:1.48±0. 07; v-n/pr-gn:2.27±0.09;n-sd/n-gn:0.62±0.02;pr-gn/n-gn:0.42±0.02;v-n/n-gn:0.95±0.02.eu-eu/v-n:1.38±0.05;zy-zy/n-sd:1.94±0.10;go-go/pr-gn:2.09±0.10.2.6 The measurement of the related angles of mandible angle by three-dimensi onal reconstructionThe related data of the mandibular angle were measured on the image of three-dimensional reconstruction,the mandibular angle (left):(124.10±4.03)°; the mandibular angle (right):(124.46±4.22)°;the mandibular elevated angle (left):(25. 42±2.17)°; the mandibular elevated angle (right):(25.61±2.28)°; the valgus angle of mandibular angle (left):(9.23±7.72)°; the valgus angle of mandibular angle (right):(9.47±8.03)°; the mandiblular included angle:(77.32±2.34)°; the tangent a ngle of mandible:(105.53±1.79)°.The linear correlation analysis of the related angles of mandibular angle and bigonial breadth:the valgus angle of mandibular angle,bigonial breadth,the mandibluar included angle,the tangent angle of mandible showed significantly positive correlation r range(0.617～0.976),(P<0.01).The mandibular angle with bigonial breadth,the mandiblular included angle, the valgus angle of mandibular angle and the tangent angle of mandible showed no significant correlation (P=0.048,P=0.019,P=0.184,P=0.019). The mandibular elevated angle with bigonial breadth,the mandiblular included angle, the valgus angle of mandibular angle and the tangent angle of mandible showed no significant correlation(P=0.303,P=0.143,P=0.709,P=0.095).The mandibular angle and the mandibular elevated angle showed a significantly positive correlation (r=0.884, P=0.000).2.7 The anatomical structure measurement of the influencement of mandibular contour by three-dimensional reconstruction.We marked points in the influencement area of mandibular contour on theimage of three dimensional reconstruction,.All these points were measured the thickness of mandible and the thickness of outer plate of mandible.The mean results of measurement right and left respectively is A point:(7.20±0.64)mm,(3.32±0.36)mm;B point:(6.58±0.66)mm,(2.85±0.34)mm;Cpoin(7.10±0.65)mm,(3.21±0.39)mm;Epoint:( 7.52±0.79)mm,(3.35±0.38)mm;Fpoint:(9.83±0.94)mm,(3.62±0.33)mm;Gpoint:(12.72±1.01)mm,(4.54±0.37)mm;Hpoint:(12.33±0.94)mm,(4.32±0.39)mmIpoint:(11.29±0.9 9)mm,(4.01±0.39);Dpoint,the thickness of the mandible:(6.66±0.85)mm;the thickness of outer plate of mandible Jpoint:(6.34±0.47)mm;K point:(5.31±0.46)mm.2.8 Surgical options on basifacial contour plastySuitable and surgical compositive options on basifacial contour plasty were choosed and carried out through preoperative classification. Mandibular angle hypertrophy plasty combined with other assistant aesthetic operations were ideal methods to recontour basifacial contour. The result was satisfaction.ConclusionThrough the study on applied anatomy of the mandibular angle region,disscussed the safe operative region and the more secure osteotomy region on mandibula rangle hypertrophy plasty;related measurrment of mandibular angle was done by spiral CT three-dimensional reconstruction and disscussed the harmonious proportional relationship of the frontal head and facial skeletal contour in normal adult female and the relationship between related angles of mandibular angle and bigonial breadth, identified the anatomical structure of the influencement of mandibular contour and associated thickness of mandible and the thickness of the outer plate of mandible. The subject ranged from applied anatomy of the mandibular angle region and the measurement of three-dimensional reconstruction to research, the results will provid anatomical basis and theoretical basis on improving safety of mandibular angle hypertrophy plasty, such as reduce bleeding, nerve damage, inferior alveolar neurovascular bundle damage and other complications; improving the effect of mandibular angle hypertrophy plasty such as reduce the bilateral asymmetry, the second mandibular angle, "horse face" deformity, excessive or too little osteotomy, insufficient or excessive narrowing of the face and other complications; improving the clinical three-dimensional diagnostic criteria of mandibular angle hypertrophy.Throng etrospectively analyzed surgical options on basifacial contour plasty of patients. Suitable and compositive surgical options on basifacial contour plasty were choosed and carried out through preoperative classification. Mandibular angle hypertrophy plasty combined with other assistant aesthetic operations were ideal methods to recontour basifacial contour. The result was satisfactory.The main innovations of this topic were:①Aim at bleeding, facial nerve damage, inferior alveolar neurovascular bundle damage and other serious complications in the clinical mandibular angle hypertrophy plasty, we studied the applied anatomy of the mandibular angle region and took the mandibular angle as the center, observed and measured the mandibular angle region's main blood vessel, nerve and mandibular canal and the position relationship between them and the mandibular angle (the exterior border of the mandible). With a view to provide anatomical basis for the safe operative region and the more secure osteotomy plane of the mandibular angle hypertrophy plasty,avoid to damage these important structures and improve the safety of mandibular angle hypertrophy plasty.②We used mimics software measure specimens by three-dimensional reconstruction, the software has many advantages such as easy installation, the computer configuration requirement is not high, reconstruction and high measuring accuracy and is equipped with a variety of measurement tools, it is easy for clinicians to master and so on.③by spiral CT three-dimensional reconstruction measurement of front view of the head and facial horizontal, vertical, vertical and horizontal proportion, studied the proportional relationship of head and facial skeletal contours more detail than the previous studies. With a view to find some rules of of horizontal,vertical as well as vertical and horizontal proportional relationship.④Related angles measurement of the mandibular angle by three-dimensional reconstruction and statistical analysis, identified the relationship between all relevant angle of mandibular and the bigonial breadth.⑤Measurement by three-dimensional reconstruction and observation, identified the the main anatomical influence factors of front and side contour of mandible and these factors were measured through the fixed-point method.And measured the thickness of mandible and the thickness of outer plate of mandible. Provided basises for the osteotomy and treatment operations on outside plate of mandible in mandibular angle hypertrophy plasty,provide theoretical supportfor doctors preoperative design and postoperative evaluated results of operations.In summary, the findings of the topic will play an active role in reducing complications and improving safety of mandibular angle hypertrophy plasty to a certain extent, provide plastic surgery mandibular angle in order to to; supply helpness for a comprehensive understanding of the frontal proportions of head and facial skeletal contour in normal adult female, theoretical support for enriching the clinical diagnosis of mandibular angle hypertrophy,improving results of operations, improving surgical satisfaction and so on.